deoxycholic-acid and Colonic-Neoplasms

Colorectal cancer (CRC) is one of the most frequent causes of cancer death worldwide and is associated with adoption of a diet high in animal protein and saturated fat. Saturated fat induces increased bile secretion into the intestine. Increased bile secretion selects for populations of gut microbes capable of altering the bile acid pool, generating tumor-promoting secondary bile acids such as deoxycholic acid and lithocholic acid. Epidemiological evidence suggests CRC is associated with increased levels of DCA in serum, bile, and stool. Mechanisms by which secondary bile acids promote CRC are explored. Furthermore, in humans bile acid conjugation can vary by diet. Vegetarian diets favor glycine conjugation while diets high in animal protein favor taurine conjugation. Metabolism of taurine conjugated bile acids by gut microbes generates hydrogen sulfide, a genotoxic compound. Thus, taurocholic acid has the potential to stimulate intestinal bacteria capable of converting taurine and cholic acid to hydrogen sulfide and deoxycholic acid, a genotoxin and tumor-promoter, respectively.

Topics: Bile; Cholagogues and Choleretics; Colonic Neoplasms; Deoxycholic Acid; Detergents; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Hydrogen Sulfide; Mutagens; Taurocholic Acid

A high-fat diet coincides with increased levels of bile acids. This increase in bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway.

Topics: Colonic Neoplasms; Deoxycholic Acid; ErbB Receptors; Humans; Mitogen-Activated Protein Kinase Kinases; Signal Transduction; Ursodeoxycholic Acid

Topics: Animals; Anticarcinogenic Agents; Butyrates; Butyric Acid; Colonic Neoplasms; Deoxycholic Acid; Diet; Humans; Mevalonic Acid

Topics: Animals; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Feces; Humans; Lithocholic Acid; Rectal Neoplasms; Structure-Activity Relationship

Topics: Adenoma; Animals; Cell Division; Cell Line; Cells, Cultured; Colonic Neoplasms; Culture Techniques; Deoxycholic Acid; Epidermal Growth Factor; Humans; Models, Biological; Plasminogen Activators; Precancerous Conditions; Tetradecanoylphorbol Acetate

Topics: Animals; Calcinosis; Chenodeoxycholic Acid; Cholelithiasis; Cholesterol; Colonic Neoplasms; Cost-Benefit Analysis; Deoxycholic Acid; Diarrhea; Female; Humans; Liver; Macaca mulatta; Male; Transaminases; Ursodeoxycholic Acid

Topics: Bile Acids and Salts; Biliary Tract Diseases; Celiac Disease; Chenodeoxycholic Acid; Cholelithiasis; Cholestasis; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Diarrhea; Humans; Intestinal Diseases; Intestine, Small; Lipid Metabolism; Lithocholic Acid; Liver; Liver Circulation; Malabsorption Syndromes; Portal System

Topics: Bile; Cellulose; Colonic Neoplasms; Constipation; Deoxycholic Acid; Dietary Fiber; Diverticulum, Colon; Edible Grain; Feces; Humans; Intestines; Varicose Veins

In Western societies colonic cancer most frequently develops in the distal colon, largely as a result of the composition of the diet. Modulation of dietary factors is therefore an attractive modality to reduce colorectal cancer risk. This study aims to evaluate the potentially protective effects of calcium in right hemicolectomy patients.. A randomized controlled cross-over intervention trial was performed with 1000 mg of elemental calcium per day for 2 months in 15 right hemicolectomy patients. Primary endpoints were proliferative activity, determined by immunohistochemical detection of BrdU-labeled cells (LI) in rectal biopsies, and cytotoxicity and alkaline phosphatase activity of faecal water. Secondary endpoints were bile acid composition in faeces.. Calcium-reduced LI in the superficial one-third of the crypt (from 0.84 +/- 0.27% to 0.37 +/- 0.08%, P = 0.04) and a trend towards a lower total LI and LI in the mid one-third of the crypt was observed. Alkaline phosphatase activity was reduced from 6.2 +/- 2.6 U mL-1 in the placebo period to 4.6 +/- 2.2 in the calcium period (P = 0.02), and a trend toward a lower cytotoxicity of faecal water was observed. No effect on total bile acids in faeces was observed, but calcium increased the percentage of deoxycholic acid (from 49.6 +/- 7.0% to 56.5 +/- 6.2%, P = 0.03) and decreased the percentages of cholic acid (from 10.3 +/- 4.7% to 5.8 +/- 2.7%, P = 0.05) and lithocholic acid (from 26.7 +/- 3.4% to 23.9 +/- 2.9%, P = 0.04).. Calcium may have a protective effect against colorectal cancer risk in right hemicolectomy patients.

Topics: Aged; Alkaline Phosphatase; Biomarkers, Tumor; Calcium; Cell Division; Cholic Acid; Colectomy; Colonic Neoplasms; Cross-Over Studies; Deoxycholic Acid; Double-Blind Method; Epithelial Cells; Feces; Female; Humans; Lithocholic Acid; Male; Middle Aged; Neoplasm Recurrence, Local; Postoperative Period

Use of calcium supplements has increased dramatically in recent years yet little is known about the effect of calcium supplementation on colon physiology. We supplemented 22 individuals with a history of resected adenocarcinoma of the colon, but currently free of cancer, with 2000 or 3000 mg calcium for 16 wk. The effects of supplementation on duodenal bile acids and important fecal characteristics including total fecal output, wet and dry weight, pH, bile acids (in solids and in fecal water), and concentrations and total excretion of calcium, magnesium, phosphates (organic and inorganic), unesterified fatty acids and total fat were determined. Calcium supplementation significantly decreased the proportion of water in the stool (P = 0.03), doubled fecal excretion of calcium (P = 0.006), and increased excretion of organic phosphate (P = 0.035) but not magnesium. Calcium supplementation significantly decreased the proportion of chenodeoxycholic acid in bile (P = 0.007) and decreased the ratio of lithocholate to deoxycholate in feces (P = 0.06). The concentration of primary bile acids in fecal water decreased after 16 wk Ca supplementation. Together with other reports of a "healthier" bile acid profile with respect to colon cancer when changes such as those observed in this study were achieved, these results suggest a protective effect of calcium supplementation against this disease.

Topics: Adenocarcinoma; Bile; Bile Acids and Salts; Calcium; Calcium, Dietary; Colon; Colonic Neoplasms; Deoxycholic Acid; Duodenum; Fatty Acids; Feces; Food, Fortified; Humans; Hydrogen-Ion Concentration; Lithocholic Acid; Magnesium; Phosphorus

Dietary fibre possibly protects against colonic cancer by effects on bile acid metabolism. We investigated the effect of a natural high-fibre diet on secondary bile acid formation. Twelve healthy subjects on an habitual low-fibre diet (for 4 weeks) consumed a high-fibre menu for 10 weeks (experimental group). A control group of 10 subjects consumed their regular high-fibre diet during this period. Faecal and biliary acid composition, faecal weight, faecal pH and gut transit time were studied before and after 6 and 10 weeks of fibre addition. Changes in the experimental group were compared to changes in the control group. The concentration, but not the excretion, of the secondary faecal bile acids was reduced in the experimental group. Faecal weight increased, faecal pH dropped and gut transit time was not altered. The biliary deoxycholic acid content decreased and the cholic acid content increased after 6 weeks, but returned to baseline values after 10 weeks of fibre addition. This study shows that a natural high-fibre diet lowers secondary faecal bile acid concentration through an increase in stool weight. The 7 alpha-dehydroxylation of primary bile acids is probably not or only transiently inhibited.

Topics: Adult; Aged; Bile Acids and Salts; Case-Control Studies; Cholic Acid; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Dietary Fiber; Energy Metabolism; Feces; Gastrointestinal Transit; Humans; Hydrogen-Ion Concentration; Middle Aged; Nutrition Assessment; Time Factors

Recent findings suggest that supplemental calcium could lower the abnormally high proliferation rate found in the colonic mucosa of subjects at high risk for colon cancer. In this double blind controlled study, this effect in volunteers previously operated upon for a colorectal adenocarcinoma was tested. Thirty subjects were randomised to receive either elemental calcium 1200 mg/day or a placebo. Mucosal proliferation was measured with tritiated thymidine labelling before and after the 30 day intervention period. Diets, faecal pH and the concentration of calcium and bile acids in the aqueous phase of feaces were also measured. Labelling index did not differ significantly in the two groups before intervention (placebo 4.0(2.4) v calcium 4.9(2.9), but the difference approached significance afterwards (4.4(2.4) v 6.5(3.4), p = 0.06). Individual changes occurring with intervention were tabulated and comparison of the means for the groups was not significant (delta = 0.3 vs delta = 1.8, p = 0.11). Calcium concentration, faecal pH and deoxycholic acid concentration increased in the calcium group (p = 0.02, 0.005 and 0.004 respectively). Calcium does not show any effect in decreasing colonic mucosal proliferation in this high risk group for colon cancer; it may increase faecal pH and the production of deoxycholic acid in the colon.

Topics: Aged; Bile Acids and Salts; Calcium; Cell Division; Colon; Colonic Neoplasms; Deoxycholic Acid; Double-Blind Method; Feces; Female; Humans; Hydrogen-Ion Concentration; Intestinal Mucosa; Male; Random Allocation; Risk Factors

Chenodeoxycholic acid and ursodeoxycholic acid (CDCA and UDCA, respectively) have been conjugated with paclitaxel (PTX) anticancer drugs through a high-yield condensation reaction. Bile acid-PTX hybrids (BA-PTX) have been investigated for their pro-apoptotic activity towards a selection of cancer cell lines as well as healthy fibroblast cells. Chenodeoxycholic-PTX hybrid (CDC-PTX) displayed cytotoxicity and cytoselectivity similar to PTX, whereas ursodeoxycholic-PTX hybrid (UDC-PTX) displayed some anticancer activity only towards HCT116 colon carcinoma cells. Pacific Blue (PB) conjugated derivatives of CDC-PTX and UDC-PTX (CDC-PTX-PB and UDC-PTX-PB, respectively) were also prepared via a multistep synthesis for evaluating their ability to enter tumor cells. CDC-PTX-PB and UDC-PTX-PB flow cytometry clearly showed that both CDCA and UDCA conjugation to PTX improved its incoming into HCT116 cells, allowing the derivatives to enter the cells up to 99.9%, respect to 35% in the case of PTX. Mean fluorescence intensity analysis of cell populations treated with CDC-PTX-PB and UDC-PTX-PB also suggested that CDC-PTX-PB could have a greater ability to pass the plasmatic membrane than UDC-PTX-PB. Both hybrids showed significant lower toxicity with respect to PTX on the NIH-3T3 cell line.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Bile Acids and Salts; Cell Line; Cell Survival; Colonic Neoplasms; Deoxycholic Acid; Humans; Leukemia; Mice; Paclitaxel

Cholecystectomy (XGB) is widely recognized as a risk factor for colon cancer (CC). Continuous exposure of the colonic epithelium to deoxycholic acid (DCA) post-XGB may exert cytotoxic effects and be involved in the progression of CC. However, the functions of the XGB-induced DCA increase and the underlying mechanism remain unclear.. Colitis-associated CC (CAC) mouse models constructed by AOM-DSS inducement were used to confirm the effect of XGB on the CC progression. Hematoxylin & eosin staining was performed to assess the tumor morphology of CAC mouse models tissues. Various cell biological assays including EdU, live-cell imaging, wound-healing assays, and flow cytometry for cell cycle and apoptosis were used to evaluate the effect of DCA on CC progression. The correlation among XGB, DCA, and CC and their underlying mechanisms were detected with immunohistochemistry, mass spectrometry, transcriptome sequencing, qRT-PCR, and western blotting.. Here we proved that XGB increased the plasma DCA level and promoted colon carcinogenesis in a colitis-associated CC mouse model. Additionally, we revealed that DCA promoted the proliferation and migration of CC cells. Further RNA sequencing showed that 120 mRNAs were upregulated, and 118 downregulated in DCA-treated CC cells versus control cells. The upregulated mRNAs were positively correlated with Wnt signaling and cell cycle-associated pathways. Moreover, DCA treatment could reduced the expression of the farnesoid X receptor (FXR) and subsequently increased the levels of β-Catenin and c-Myc in vitro and in vivo. Moreover, the FXR agonist GW4064 decreased the proliferation of CC cells by repressing the expression of β-catenin.. We concluded that XGB-induced DCA exposure could promote the progression of CC by inhibiting FXR expression and enhancing the Wnt-β-catenin pathway. Video Abstract.

Topics: Animals; beta Catenin; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Cholecystectomy; Colitis; Colonic Neoplasms; Deoxycholic Acid; Gene Expression Regulation, Neoplastic; Mice; Wnt Signaling Pathway

Camptothecin (CPT) is known as an anticancer drug in traditional Chinese medicine. However, due to the lack of targeting, low solubility, and instability of CPT, its therapeutic applications are hampered. Therefore, we synthesized a series of CPT-bile acid analogues that obtained a national patent to improve their tumour-targeting chemotherapeutic effects on liver or colon cancers. Among these analogues, the compound G2 shows high antitumor activity with enhanced liver targeting and improved oral absorption. It is significant to further investigate the possible anticancer mechanism of G2 for its further clinical research and application.. We aimed to unearth the anticancer mechanism of G2 in HepG2 and HCT116 cells.. Cell viability was measured using MTT assay; cell cycle, Mitochondrial Membrane Potential (MMP), and cell apoptosis were detected by flow cytometer; ROS was measured by Fluorescent Microplate Reader; the mRNA and protein levels of cell cycle-related and apoptosis-associated proteins were examined by RT-PCR and western blot, respectively.. We found that G2 inhibited cells proliferation of HepG2 and HCT116 remarkably in a dosedependent manner. Moreover, G2-treatment led to S and G2/M phase arrest in both cells, which could be elucidated by the change of mRNA levels of p21, p27 and Cyclin E and the increased protein level of p21. G2 also induced dramatically ROS accumulated and MMP decreased, which contributed to the apoptosis through activation of both the extrinsic and intrinsic pathways via changing the genes and proteins expression involved in apoptosis pathway in both of HepG2 and HCT116 cells.. These findings suggested that the apoptosis in both cell lines induced by G2 was related to the extrinsic and intrinsic pathways.

Topics: Antineoplastic Agents; Apoptosis; Camptothecin; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Deoxycholic Acid; HCT116 Cells; Hep G2 Cells; Humans; Liver Neoplasms; Membrane Potential, Mitochondrial; Reactive Oxygen Species

High-fat diet, which leads to an increased level of deoxycholic acid (DCA) in the intestine, is a major environmental factor in the development of colorectal cancer (CRC). However, evidence relating to bile acids and intestinal tumorigenesis remains unclear. In this study, we investigated the effects of DCA on the intestinal mucosal barrier and its impact on the development of CRC. Here we showed that DCA disrupted cell monolayer integrity and increased proinflammatory cytokine production in intestinal cancer and precancerous cell lines (Caco-2 and IMCE). Apcmin/+ mice receiving DCA increased the number and size of intestinal adenomas and promoted the adenoma-adenocarcinoma sequence. Importantly, DCA induced the activation of the NLRP3 inflammasome, increased the production of inflammatory cytokines, and led to intestinal low grade inflammation. A reduction of tight junction protein zonula occludens 1 (ZO-1) and the number of intestinal cells including goblet cells and Paneth cells was also observed after DCA treatment. Moreover, DCA significantly reduced the level of secretory immunoglobulin A (sIgA), and promoted the polarization of M2 macrophages in the intestine of Apcmin/+ mice. In conclusion, these data suggested that DCA induced intestinal low grade inflammation and disrupted the mucosal physical and functional barriers, aggravating intestinal tumorigenesis.

Topics: Animals; Caco-2 Cells; Carcinogenesis; Colonic Neoplasms; Deoxycholic Acid; Diet, High-Fat; Female; Humans; Immunoglobulin A, Secretory; Inflammasomes; Intestinal Absorption; Intestinal Mucosa; Intestines; Mice; Zonula Occludens-1 Protein

The effects on lipid and glucose metabolism of a hazelnut skin extract (FIBEROX™) administrated during 8 weeks (HFD-FBX8w group) or during the last 4 weeks of the study (HFD-FBX4w group) to Golden Syrian hamsters fed a high-fat diet (HFD) for 8 weeks were investigated. FIBEROX™ consumption reversed the increase in total and LDL plasma cholesterol induced by the HFD feeding in both HFD-FBX groups and decreased the circulating levels of free fatty acids and triglycerides in the HFD-FBX4w animals. The higher excretion of bile acids found in the faeces of both groups of hamsters fed the FIBEROX™ suggests that this mechanism is involved in the cholesterol-lowering effects of the extract. Furthermore, FIBEROX™ intake sharply decreased the lithocholic/deoxycholic bile acid faecal ratio, a risk factor for colon cancer, in both HFD-FBX groups. In conclusion, the consumption of FIBEROX™ improves different risk factors associated with cardiovascular disease and colon cancer.

Topics: Animals; Bile Acids and Salts; Colonic Neoplasms; Corylus; Cricetinae; Deoxycholic Acid; Diet, High-Fat; Lipids; Lithocholic Acid; Male; Mesocricetus; Risk Factors

Consumption of a high-fat diet causes an increase in bile acid deoxycholic acid (DCA) in colon lumen and colon cancer risk, while butyrate, an intestinal microbiota metabolite of dietary fiber, has been shown to exhibit colon cancer-preventive effects. To distinguish these opposing effects of DCA and butyrate (two major metabolites in colon lumen), we examined the effects of physiologically relevant doses of butyrate (0.5-2 mmol/l) and DCA (0.05-0.3 mmol/l) on colon cell proliferation. We hypothesize that butyrate and DCA each modulates the cell cycle and apoptosis via common and distinct cellular signaling targets. In this study, we demonstrated that both butyrate and DCA inhibited cell proliferation by up to 89% and 92% and increased cell apoptosis rate by up to 3.1- and 4.5-fold, respectively. Cell cycle analyses revealed that butyrate led to an increase in G1 and G2 fractions with a concomitant drop in the S-phase fraction, but DCA induced an increase in only G1 fraction with a concomitant drop in the S-phase fraction when compared with the untreated cells. The examination of early cellular signaling revealed that DCA but not butyrate increased intracellular reactive oxygen species, genomic DNA breakage, the activation of ERK1/2, caspase-3 and PARP. In contrast, DCA decreased activated Rb protein level, and butyrate but not DCA increased p21 expression. Collectively, although both butyrate and DCA inhibit colonic cell proliferation, butyrate increases tumor suppressor gene expression, whereas DCA decreases tumor suppressor activation in cell cycle and apoptosis pathways.

Topics: Apoptosis; Butyrates; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Deoxycholic Acid; Genes, Tumor Suppressor; HCT116 Cells; Humans; Signal Transduction

To assess whether deoxycholic acid (DOC) and lithocholic acid (LCA) administered in a period of six months in a concentration of 0.25% may have a carcinogenic role in mice colon.. The study used C57BL6 female mice divided into four groups. The control group received a balanced diet and the others received diets supplemented with 0.25% DOC, 0.25% LCA and 0.125% DOC+0.125% LCA, respectively. After euthanasia, the lesions found in the resected gastrointestinal tracts were stained with hematoxylin-eosin and examined microscopically.. No gastrointestinal tract changes were observed in the control group, while hyperplastic Peyer's patches in the small intestine, flat adenomas with mild dysplasia and chronic colitis at the level of the colon were found in all three test groups. The colonic lesions prevailed in the proximal colon. The highest number of flat adenoma lesions (8), hyperplasia of Peyer's patches (25) and chronic colitis (2) were found in mice fed with diet and LCA.. Precancerous or cancerous pathological lesions could not be identified. Instead, adenomatous colonic injuries occurred in a shorter period of time (six months), compared to the reported data.

Topics: Adenoma; Animals; Bile Acids and Salts; Carcinogenicity Tests; Carcinogens; Cholagogues and Choleretics; Colitis; Colon; Colonic Neoplasms; Deoxycholic Acid; Disease Models, Animal; Feces; Female; Lithocholic Acid; Mice, Inbred C57BL; Peyer's Patches; Time Factors

Topics: Animals; Colonic Neoplasms; Deoxycholic Acid; Diet, High-Fat; Feces; Lithocholic Acid; Male; Vitamin B 6

We propose that the influence of diet on colon cancer risk is mediated by the microbiota. To investigate how dietary fat influences risk, we compared the colonic contents of 12 adult high-risk African Americans (AAs) and 10 Caucasian Americans (CAs) who consumed a high-fat diet (123 ± 11 g/d and 129 ± 17 g/d, respectively) to 13 native Africans (NAs) who subsisted on a low-fat (38 ± 3.0 g/d) diet, all aged 50-60 yr. The colonic bile acids were measured by LC-MS and the short-chain fatty acids (SCFAs) by GC. The chief secondary colonic bile acids, deoxycholic acid and lithocholic acid, were correlated with fat intake and similar between AAs and CAs, but 3-4 times higher than in AAs (p < 0.05). The major SCFAs were lower in AAs (p < 0.001) and CAs (p < 0.001) compared to AAs, but conversely, the branched chain fatty acids (BFCA) were higher. Our results suggest that the higher risk of colon cancer in Americans may be partly explained by their high-fat and high-protein, low complex carbohydrate diet, which produces colonic residues that promote microbes to produce potentially carcinogenic secondary bile acids and less antineoplastic SCFAs. The role of BCFA in colonic carcinogenesis deserves further study.

Topics: Bile Acids and Salts; Black or African American; Cholic Acid; Colonic Neoplasms; Deoxycholic Acid; Diet, High-Fat; Dietary Fats; Fatty Acids, Volatile; Feces; Female; Humans; Lithocholic Acid; Male; Middle Aged; Pennsylvania; Risk Factors; South Africa; White People

It is proven that nuts contain essential macro- and micronutrients, e.g. fatty acids, vitamins and dietary fibre (DF). Fermentation of DF by the gut microflora results in the formation of SCFA which are recognised for their chemopreventive potential, especially by influencing cell growth. However, little is known about cellular response to complex fermentation samples of nuts. Therefore, we prepared and analysed (pH, SCFA, bile acids, tocopherol, antioxidant capacity) fermentation supernatant (fs) fractions of nuts (almonds, macadamias, hazelnuts, pistachios, walnuts) after in vitro fermentation and determined their effects on growth of HT29 cells as well as their genotoxic/anti-genotoxic potential. The fermented nut samples contained 2- to 3-fold higher amounts of SCFA than the faeces control, but considerable reduced levels of bile acids. While most of the investigated native nuts comprised relatively high amounts of tocopherol (α-tocopherol in almonds and hazelnuts and γ- and δ-tocopherol in pistachios and walnuts), rather low concentrations were found in the fs. All nut extracts and nut fs showed a strong antioxidant potential. Furthermore, all fs, except the fs pistachio, reduced growth of HT29 cells significantly. DNA damage induced by H₂O₂ was significantly reduced by the fs of walnuts after 15 min co-incubation of HT29 cells. In conclusion, this is the first study which presents the chemopreventive effects (reduction of tumour-promoting desoxycholic acid, rise in chemopreventive SCFA, protection against oxidative stress) of different nuts after in vitro digestion and fermentation, and shows the potential importance of nuts in the prevention of colon cancer.

Topics: Adenocarcinoma; Anticarcinogenic Agents; Antimutagenic Agents; Antioxidants; Cell Proliferation; Colonic Neoplasms; Deoxycholic Acid; Digestion; DNA Damage; Fatty Acids, Volatile; Fermentation; HT29 Cells; Humans; Hydrogen-Ion Concentration; Mutagenicity Tests; Mutagens; Nuts; Oxidative Stress; Plant Extracts; Solubility

We previously demonstrated that ursodeoxycholic acid (UDC) requires prolonged (≥5 h) preincubation to exhibit effective protection of colon cancer HCT116 cells from deoxycholic acid (DC)-induced apoptosis. Although UDC diminished DC-mediated caspase-9 activation, cytochrome c release from the mitochondria was not inhibited, indicating that UDC acts on the steps of caspase-9 activation. In the present study, therefore, we investigated the effects of UDC on the factors involved in caspase-9 activation. We found that UDC had no significant effect on the expression of antiapoptotic XIAP. Furthermore, UDC did not affect the expression or release of proapoptotic Smac/DIABLO, or the association of XIAP and Smac/DIABLO. In contrast, association of Apaf-1 and caspase-9 stimulated by 500 μM DC was inhibited by UDC pretreatment. Although UDC caused remarkable activation of Akt/PKB, phosphatidylinositol-3-kinase (PI3K) inhibitor did not significantly reduce UDC-mediated cytoprotection. Furthermore, phosphorylation of threonine residues on caspase-9 after UDC pretreatment could not be detected. UDC-mediated cytoprotection was independent of the MAPK pathway, and cyclic AMP (cAMP) analogue did not inhibit DC-induced apoptosis. Our results indicate that UDC protects colon cancer cells from apoptosis induced by hydrophobic bile acids, by inhibiting apoptosome formation independently of the survival signals mediated by the PI3K, MAPK, or cAMP pathways.

Topics: Apoptosis; Apoptosomes; Apoptotic Protease-Activating Factor 1; Caspase 9; Caspase Inhibitors; Colonic Neoplasms; Deoxycholic Acid; HCT116 Cells; Humans; Mitochondria; Proto-Oncogene Proteins c-akt; Ursodeoxycholic Acid; X-Linked Inhibitor of Apoptosis Protein

To examine the effect of supplemental dietary vitamin B(6) on the colonic luminal environment, growing male rats were fed a high-fat diet containing 1, 7, or 35 mg pyridoxine HCl/kg diet for 6 wk. Food intake and growth were unaffected by the dietary treatment. Supplemental dietary vitamin B(6) significantly reduced the production of a fecal secondary bile acid, lithocholic acid (the most toxic secondary bile acid and a risk factor for colon cancer), and markedly reduced the ratio of lithocholic acid to deoxycholic acid (a less toxic secondary bile acid) in feces (p<0.05). Increasing dietary vitamin B(6) increased fecal mucin levels (a marker of intestinal barrier function) in a dose-dependent manner (p<0.05) but did not affect fecal immunoglobulin A levels (an index of intestinal immune function). Cecal levels of organic acids were not significantly affected by supplemental dietary vitamin B(6). These results suggest the possibility that dietary vitamin B(6) affects the colonic luminal environment by altering the production of secondary bile acids and mucins.

Topics: Animals; Bile Acids and Salts; Cecum; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet, High-Fat; Dietary Fats; Feces; Lithocholic Acid; Male; Mucins; Rats; Rats, Sprague-Dawley; Risk Factors; Vitamin B 6

The orphan nuclear receptor Nur77 is an immediate-early response gene whose expression is rapidly induced by various extracellular stimuli. The aims of this study were to study the role of Nur77 expression in the growth and survival of colon cancer cells and the mechanism by which Nur77 expression was regulated. We showed that levels of Nur77 were elevated in a majority of human colon tumors (9/12) compared to their nontumorous tissues and that Nur77 expression could be strongly induced by different colonic carcinogens including deoxycholic acid (DCA). DCA-induced Nur77 expression resulted in up-regulation of antiapoptotic BRE and angiogenic VEGF, and it enhanced the growth, colony formation, and migration of colon cancer cells. In studying the mechanism by which Nur77 was regulated in colon cancer cells, we found that β-catenin was involved in induction of Nur77 expression through its activation of the transcriptional activity of AP-1 (c-Fos/c-Jun) that bound to and transactivated the Nur77 promoter. Together, our results demonstrate that Nur77 acts to promote the growth and survival of colon cancer cells and serves as an important mediator of the Wnt/β-catenin and AP-1 signaling pathways.

Topics: Animals; beta Catenin; Blotting, Western; Cell Proliferation; Cell Survival; Colon; Colonic Neoplasms; Deoxycholic Acid; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Immunohistochemistry; JNK Mitogen-Activated Protein Kinases; Male; Mice; Nuclear Receptor Subfamily 4, Group A, Member 1; Phosphatidylinositol 3-Kinases; Promoter Regions, Genetic; Protein Binding; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Signal Transduction; Transcription Factor AP-1

High dietary fat causes increased bile acid secretion into the gastrointestinal tract and is associated with colon cancer. Since the bile acid deoxycholic acid (DOC) is suggested to be important in colon cancer etiology, this study investigated whether DOC, at a high physiologic level, could be a colon carcinogen. Addition of 0.2% DOC for 8-10 months to the diet of 18 wild-type mice induced colonic tumors in 17 mice, including 10 with cancers. Addition of the antioxidant chlorogenic acid at 0.007% to the DOC-supplemented diet significantly reduced tumor formation. These results indicate that a high fat diet in humans, associated with increased risk of colon cancer, may have its carcinogenic potential mediated through the action of bile acids, and that some dietary anti-oxidants may ameliorate this carcinogenicity.

Topics: Animals; Antioxidants; Bile Acids and Salts; Carcinogenicity Tests; Chlorogenic Acid; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Male; Mice; Risk

In this study, we synthesized deoxycholic acid (DA)-conjugated dextran (DexDA) and prepared doxorubicin (DOX)-encapsulated nanoparticles using DexDA conjugates. Since DexDA conjugates have amphiphilic properties, they will show self-aggregation behavior at aqueous environment. To approve self-aggregation behavior, critical aggregation concentration value of DexDA conjugates was evaluated using fluorescence spectroscopy. DOX-incorporated DexDA nanoparticles were less than 200 nm. The higher substitution degree of DA and higher drug feeding ratio resulted in increased particle size. Drug release was decreased by increase of substitution degree value of DA and increase of drug feeding ratio. At in vitro cytotoxicity test using DOX-resistant CT26 colon carcinoma cells, higher antitumor activity was obtained with DOX-incorporated nanoparticles compared to free DOX. Fluorescence microscopic observation verified this result, i.e. nanoparticles were properly entered into tumors cells and maintained longer compared to DOX itself. These results suggested that DOX-incorporated DexDA nanoparticles are promising vehicles for antitumor drug delivery.

Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; Colonic Neoplasms; Deoxycholic Acid; Doxorubicin; Drug Carriers; Mice; Nanoparticles; Particle Size; Spectrometry, Fluorescence

Topics: Animals; Chlorogenic Acid; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Male

The continuous exposure of the colonic epithelium to high concentrations of bile acids may exert cytotoxic effects and has been related to pathogenesis of colon cancer. A better knowledge of the mechanisms by which bile acids induce toxicity is still required and may be useful for the development of new therapeutic strategies. We have studied the effect of deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) treatments in BCS-TC2 human colon adenocarcinoma cells. Both bile acids promote cell death, being this effect higher for CDCA. Apoptosis is detected after 30 min-2 h of treatment, as observed by cell detachment, loss of membrane asymmetry, internucleosomal DNA degradation, appearance of mitochondrial transition permeability (MPT), and caspase and Bax activation. At longer treatment times, apoptosis is followed in vitro by secondary necrosis due to impaired mitochondrial activity and ATP depletion. Bile acid-induced apoptosis is a result of oxidative stress with increased ROS generation mainly by activation of plasma membrane enzymes, such as NAD(P)H oxidases and, to a lower extent, PLA2. These effects lead to a loss of mitochondrial potential and release of pro-apoptotic factors to the cytosol, which is confirmed by activation of caspase-9 and -3, but not caspase-8. This initial apoptotic steps promote cleavage of Bcl-2, allowing Bax activation and formation of additional pores in the mitochondrial membrane that amplify the apoptotic signal.

Topics: Adenocarcinoma; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Survival; Chenodeoxycholic Acid; Colonic Neoplasms; Deoxycholic Acid; Humans; Membrane Potential, Mitochondrial; Mitochondria; Necrosis; Oxidative Stress; Reactive Oxygen Species

The cell growth inhibition induced by bile acid deoxycholic acid (DCA) may cause compensatory hyperproliferation of colonic epithelial cells and consequently increase colon cancer risk. On the other hand, there is increasing evidence for the efficacy of certain forms of selenium (Se) as anticancer nutrients. Methylselenol has been hypothesized to be a critical Se metabolite for anticancer activity in vivo. In this study, we demonstrated that both DCA (75-300 micromol/l) and submicromolar methylselenol inhibited colon cancer cell proliferation by up to 64% and 63%, respectively. In addition, DCA and methylselenol each increased colon cancer cell apoptosis rate by up to twofold. Cell cycle analyses revealed that DCA induced an increase in only the G1 fraction with a concomitant drop in G2 and S-phase; in contrast, methylselenol led to an increase in the G1 and G2 fractions with a concomitant drop only in the S-phase. Although both DCA and methylselenol significantly promoted apoptosis and inhibited cell growth, examination of mitogen-activated protein kinase (MAPK) pathway activation showed that DCA, but not methylselenol, induced SAPK/JNK1/2, p38 MAPK, ERK1/2 activation. Thus, our data provide, for the first time, the molecular basis for opposite effects of methylselenol and DCA on colon tumorigenesis.

Topics: Apoptosis; Cell Cycle; Colonic Neoplasms; Deoxycholic Acid; Enzyme Activation; G1 Phase; G2 Phase; HCT116 Cells; Humans; Methanol; Mitogen-Activated Protein Kinases; Organoselenium Compounds; S Phase; Signal Transduction

Deoxycholic acid (DCA) is a secondary bile acid that modulates signalling pathways in epithelial cells. DCA has been implicated in pathogenesis of colon carcinoma, particularly by activation of the protein kinase C (PKC) pathway. Ursodeoxycholic acid (UDCA), a tertiary bile acid, has been observed to have chemopreventive effects. The aim of this study was to investigate the effect of DCA and UDCA on the subcellular localization and activity of PKCeta and its downstream effects on Golgi structure in a colon cancer cell model. PKCeta expression was localized to the Golgi in HCT116 colon cancer cells. DCA induced fragmentation of the Golgi in these cells following activation of PKCeta and its downstream effector protein kinase D (PKD). Pretreatment of cells with UDCA or a glucocorticoid, dexamethasone, inhibited DCA-induced PKCeta/PKD activation and Golgi fragmentation. Knockdown of glucocorticoid receptor (GR) expression using small interfering RNA or inhibition using the GR antagonist mifepristone attenuated the inhibitory effect of UDCA on Golgi fragmentation. Elevated serum and faecal levels of DCA have been previously reported in patients with ulcerative colitis (UC) and colon cancer. Analysis of Golgi architecture in vivo using tissue microarrays revealed Golgi fragmentation in UC and colorectal cancer tissue. We have demonstrated that DCA can disrupt the structure of the Golgi, an organelle critical for normal cell function. Inhibition of this DCA-induced Golgi fragmentation by UDCA was mediated via the GR. This represents a potential mechanism of observed chemopreventive effects of UDCA in benign and malignant disease of the colon.

Topics: Bile Acids and Salts; Colitis, Ulcerative; Colonic Neoplasms; Deoxycholic Acid; Dexamethasone; Golgi Apparatus; HCT116 Cells; Humans; Phosphorylation; Protein Kinase C; Receptors, Glucocorticoid; Ursodeoxycholic Acid

Topics: Adenoma; Animals; Cholagogues and Choleretics; Colon; Colonic Neoplasms; Deoxycholic Acid; Dietary Supplements; Mice; Mice, Inbred C57BL

MUC2 is a major secretory mucin normally expressed by goblet cells of the intestine, but is aberrantly expressed in colonic neoplasia. Bile acids have been implicated in colorectal carcinogenesis and, therefore, we sought to determine the effects of bile acids on MUC2 expression and regulation in colon cancer cells. Since deoxycholic acid (DCA), a secondary bile acid, has been reported to be a potent mucin secretagogue and tumor promoter, DCA-treated HM3 colon cancer cells were analyzed using promoter-reporter assays of the 5' flanking region of the MUC2 gene. Chemical inhibitors, mutant reporter constructs and EMSA showed that DCA upregulates MUC2 transcription via multiple pathways involving activation of EGFR/PKC/Ras/Raf-1/MEK1/ERK/CREB, PI3/Akt/IkappaB/NF-kappaB and p38/MSK1/CREB while DCA induced MUC2 transcription is inhibited by JNK/c-Jun/AP-1 pathway. These results provide new insight into the complex molecular mechanisms involved in the regulation of mucin gene by bile acids in colon cancer cells that may contribute to further elucidation of colorectal carcinogenesis.

Topics: 5' Flanking Region; Cell Line, Tumor; Colonic Neoplasms; Cyclic AMP Response Element-Binding Protein; Deoxycholic Acid; Dose-Response Relationship, Drug; Enzyme Inhibitors; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Neoplastic; Humans; I-kappa B Proteins; JNK Mitogen-Activated Protein Kinases; Mucin-2; Mutation; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase C; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-jun; ras Proteins; Ribosomal Protein S6 Kinases, 90-kDa; Signal Transduction; Sp1 Transcription Factor; Time Factors; Transcription Factor AP-1; Transcription, Genetic; Transfection

We show, for the first time, that hydrophobic bile acids cause aberrations of the mitotic machinery of colon cells that can give rise to aneuploidy, the chromosomal perturbations common in colon tumors. First, we show that DOC induces a statistically significant fourfold increase in the number of micronuclei in NCM-460 cells (a noncancerous colon cell line) and a threefold increase in the number of micronuclei in binucleated HT-29 colon cancer cells using the cytokinesis block micronucleus assay. Second, we observed mitotic aberrations after DOC treatment, including improper alignment of chromosomes at the metaphase plate, lagging chromosomes during anaphase, anaphase/telophase chromatin bridges, multipolar divisions, and formation of polynucleated cells. It was determined that there was a statistically significant threefold increase in the number of aberrant metaphases after short-term and long-term exposure of HT-29 and HCT-116 cells, respectively. Third, we showed with Western blots and immunohistochemistry that a likely basis for these mitosis-related perturbations included decreased expression of the spindle checkpoint proteins, Mad2, BubR1, and securin. Fourth, results of DOC treatment on nocodazole-challenged cells further indicated deficiencies in activation of the spindle assembly checkpoint. This study provides mechanisms by which hydrophobic bile acids can induce genomic instability in colon epithelial cells.

Topics: Cell Line, Tumor; Colonic Neoplasms; Deoxycholic Acid; Genomic Instability; Humans; Hydrophobic and Hydrophilic Interactions; Micronuclei, Chromosome-Defective; Mitosis; Nocodazole; Spindle Apparatus

This study was performed to examine the effect of dietary polyphenols on fecal secondary bile acids, such as deoxycholic acid and lithocholic acid, the risk factors of colon cancer, in rats fed a high-fat diet. In experiment 1, rats were fed a 30% beef tallow diet containing 0.5% polyphenols for 3 weeks. Dietary curcumin and caffeic acid significantly reduced the fecal concentration of deoxycholic acid. Dietary caffeic acid, catechin, rutin, and ellagic acid significantly reduced fecal lithocholic acid. Fecal hyodeoxycholic acid, a metabolite of lithocholic acid, was markedly lowered by dietary curcumin, caffeic acid, catechin, and rutin. In experiment 2, rats were fed a 30 or 5% beef tallow diet with or without the addition of 0.5% curcumin. In the rats without receiving curcumin, the fecal level of deoxycholic acid was significantly higher in the high-fat diet group than in the low-fat diet group. Fecal deoxycholic acid was significantly reduced by dietary curcumin in the high-fat diets but not in the low-fat diets. The results suggest novel effects of some polyphenols favorable for colon health by reducing secondary bile acids in animals fed a high-fat diet.

Topics: Animals; Anticarcinogenic Agents; Caffeic Acids; Colonic Neoplasms; Curcumin; Deoxycholic Acid; Diet; Dietary Fats; Feces; Flavonoids; Lithocholic Acid; Male; Phenols; Polyphenols; Rats; Rats, Sprague-Dawley; Risk Factors

The orphan nuclear receptor pregnane X receptor (PXR) plays an important role in the detoxification of foreign and endogenous chemicals, including bile acids. PXR promotes bile acid elimination by activating bile acid-detoxifying enzymes and transporters. Certain bile acids are known to promote colonic carcinogenesis by inducing colon cancer cell apoptosis. However, whether and how PXR plays a role in colon cancer apoptosis has not been reported. In this study, we showed that activation of PXR by genetic (using a constitutively activated PXR) or pharmacological (using PXR agonist rifampicin) means protected the PXR-overexpressing colon cancer HCT116 cells from deoxycholic acid-induced apoptosis. Interestingly, activation of PXR also protected HCT116 cells from adriamycin-induced cell death, suggesting that the antiapoptotic effect of PXR was not bile acid specific. Moreover, the antiapoptotic effect of PXR in HCT116 cells appeared to be independent of xenobiotic enzyme regulation, because these cells had little basal and inducible expression of bile acid-detoxifying enzymes. Instead, SuperArray analysis showed that PXR-mediated deoxycholic acid resistance was associated with up-regulation of multiple antiapoptotic genes, including BAG3, BIRC2, and MCL-1, and down-regulation of proapoptotic genes, such as BAK1 and TP53/p53. Treatment with rifampicin in colon cancer LS180 cells, a cell line known to express endogenous PXR, also inhibited apoptosis. Activation of PXR in transgenic mice inhibited bile acid-induced colonic epithelial apoptosis and sensitized mice to dimethylhydrazine-induced colonic carcinogenesis, suggesting that the antiapoptotic effect of PXR is conserved in normal colon epithelium. In summary, our results have established the antiapoptotic role of PXR in both human colon cancer cells and normal mouse colon epithelium.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Apoptosis Regulatory Proteins; bcl-2 Homologous Antagonist-Killer Protein; Blotting, Western; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Doxorubicin; Epithelial Cells; Flow Cytometry; HCT116 Cells; Humans; In Situ Nick-End Labeling; Inhibitor of Apoptosis Proteins; Mice; Mice, Transgenic; Myeloid Cell Leukemia Sequence 1 Protein; Pregnane X Receptor; Proto-Oncogene Proteins c-bcl-2; Receptors, Steroid; Reverse Transcriptase Polymerase Chain Reaction; Rifampin; Ubiquitin-Protein Ligases

In the human colon cancer cells HCT116, deoxycholic acid (DCA) induces apoptosis via the mitochondrial pathway by triggering the release of mitochondrial factors such as cytochrome c. To elucidate if Bax, a proapoptotic member of the Bcl-2 family known to trigger cytochrome c release in response to various types of apoptotic stimuli, is involved in DCA-induced apoptosis in HCT116 cells, we analyzed DCA-induced apoptosis in Bax-knockout (Bax(-/-)) HCT116 cells. Cytochrome c release and caspase-9 activation were detectable after 5 min in both Bax(-/-) and Bax(+/-) HCT116 cells. Caspase-3 and caspase-8 activation was observed after 15 and 30 min, respectively. Bax(-/-) cells were protected from apoptosis by treating them with ursodeoxycholic acid for 12 h prior to DCA treatment. These results are consistent with our previous observations that were obtained by using wild-type HCT116 cells and suggest that Bax is not indispensable for DCA-induced apoptosis in HCT116 cells.

Topics: Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 8; Caspase 9; Caspases; Colonic Neoplasms; Deoxycholic Acid; Enzyme Activation; HCT116 Cells; Humans; Ursodeoxycholic Acid

AKR/J mice are resistant to the tumorigenic properties of the colon carcinogen, azoxymethane (AOM). Following AOM exposure, limited numbers of preneoplastic lesions, referred to as aberrant crypt foci (ACF), are formed in the colon, and their progression to tumors rarely occurs. To determine whether genetic resistance can be overcome by exposure to a dietary tumor promoter, AOM-exposed AKR/J mice were fed a diet containing 0.25% deoxycholic acid (DCA). DCA exposure was begun 1 wk prior to or 1 wk after tumor initiation with AOM. Mice placed on the DCA diet prior to AOM treatment developed a significantly higher multiplicity of ACF compared to AOM-exposed mice fed a control diet (15.50 +/- 0.96 vs. 6.17 +/- 0.48, respectively; P < 0.05). When DCA exposure was begun after AOM treatment (post-initiation), ACF formation was further enhanced (34.00 +/- 1.22). Interestingly, increased numbers of ACF were associated with the presence of nuclear beta-catenin, assessed by immunohistochemistry. While approximately 33% of ACF from mice exposed to DCA prior to AOM treatment contained positive nuclear beta-catenin staining, approximately 77% of ACF from mice fed DCA after AOM were positive. Accumulation of nuclear beta-catenin was not associated with a loss of E-cadherin from the plasma membrane, although loss of APC staining was a consistent feature of most AOM-induced ACF, regardless of DCA exposure. These results demonstrate that exposure to DCA, an important digestive component, is sufficient to sensitize the resistant AKR/J colon to formation of high-grade dysplasia, and that nuclear translocation of beta-catenin may play an important role in this process.

Topics: Animals; Azoxymethane; beta Catenin; Cadherins; Carcinogens; Cell Nucleus; Colon; Colonic Neoplasms; Deoxycholic Acid; Detergents; Hyperplasia; Male; Mice; Mice, Inbred AKR; Precancerous Conditions; Protein Transport

Deoxycholic acid (DCA) is an endogenous secondary bile acid implicated in numerous pathological conditions including colon cancer formation and progression and cholestatic liver disease. DCA involvement in these disease processes results partly from its ability to modulate signaling cascades within the cell, presumably through both direct receptor activation and general detergent mediated membrane changes. To further explore DCA induced changes in cell signaling, we completed a total synthesis of enantiomeric deoxycholic acid (ent-DCA) from achiral 2-methyl-1,3-cyclopentanedione. Using a modified method of the synthesis of ent-testosterone that proceeds through the (R)-(-)-Hajos-Parrish ketone, we have completed the successful synthesis of ent-DCA in 25 steps with a yield of 0.3% with all stereochemical assignments of the product confirmed by X-ray crystallography. Our studies toward this synthesis also uncovered the methodology for the development of a novel A,B-cis steroidal skeleton system containing a C3-C9 single bond as well as conditions to selectively ketalize the typically less reactive 12-carbonyl in poly-keto A,B-cis androgens. The critical micelle concentration (cmc) of ent-DCA, determined by a dye solubilization method, was identical to the cmc of natural DCA. Toxicity studies toward HT-29 and HCT-116 human colon cancer cell lines demonstrated that ent-DCA had similar effects on proliferation, yet showed a markedly decreased ability to induce apoptosis as compared to natural DCA.

Topics: Antineoplastic Agents; Bile Acids and Salts; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Cyclopentanes; Deoxycholic Acid; HCT116 Cells; HT29 Cells; Humans; Time Factors

Deoxycholic acid (DCA) has been implicated in colorectal carcinogenesis in humans with effects on proliferation and apoptosis, mediated at least in part by activation of transcription factors nuclear factor kappa B (NF-kappaB), activator protein 1 (AP-1) and protein kinase C (PKC) enzymes. Ursodeoxycholic acid (UDCA) is reported to reduce the frequency of colonic carcinogenesis in ulcerative colitis patients. Hence, we postulated that it might differ from DCA in its regulation of these transcription factors. The aim of the study was to determine effects of DCA and UDCA on NF-kappaB and AP-1 activation and explore its relationship to PKC. Human colonic tumour cell lines HCT116 were treated with DCA, UDCA, alone or pretreated with UDCA followed by DCA or IL-1beta. In other experiments, cells were pretreated with PKC inhibitors and then stimulated with DCA and IL-1beta or PMA. Gel shift assays were performed on nuclear extracts of the cells for NF-kappaB and AP-1 analysis. Western blot analyses and immunofluorescence were performed for Rel A (p65) and IkappaB-alpha levels on the treated cells. DCA increased NF-kappaB and AP-1 DNA binding. UDCA did not increase DNA binding of NF-kappaB and AP-1 and UDCA pretreatment inhibited DCA-induced NF-kappaB and AP-1 DNA binding. PKC inhibitors blocked DCA-induced NF-kappaB and AP-1 activation. These results were validated by Western blot analysis for RelA and IkappaB-alpha. In conclusion, UDCA did not induce NF-kappaB and AP-1 DNA binding but also blocked DCA-induced NF-kappaB and AP-1 activation. These findings suggest a possible mechanistic role for UDCA in blocking pathways thought to be involved in colon carcinogenesis.

Topics: Binding Sites; Blotting, Western; Cholagogues and Choleretics; Colonic Neoplasms; Deoxycholic Acid; Electrophoretic Mobility Shift Assay; HCT116 Cells; Humans; Interleukin-1; NF-kappa B; Protein Kinase C; Transcription Factor AP-1; Ursodeoxycholic Acid

Apoptosis resistance, a condition favoring genomic instability, is associated with higher risk of colorectal cancer. Deoxycholate (DOC) is a hydrophobic bile salt found in high concentrations in colon cancer patients, and induces apoptosis in cultured colonic cells and ex vivo in colonic biopsies. We showed previously that the chronic exposure of colon cancer cells to increasing concentrations of DOC leads to apoptosis resistance, and the suggested mechanism involves oxidative/nitrosative stress. Nitric oxide (NO) is a key signaling molecule that regulates cell function in a variety of physiologic and pathophysiologic states. In part, NO exerts its actions by S-nitrosylation of target thiols, and several proteins are regulated through this PTM, including the caspases, the main effectors of apoptosis. Here, we performed a proteomics study in the DOC-induced apoptosis-resistant colon cell line, HCT-116RC. Its profile of S-nitrosylated proteins was compared to a control cell line not exposed to DOC. Eighteen differentially S-nitrosylated proteins were identified in the HCT-116RC cell line, 14 of these are novel targets of S-nitrosylation not previously reported. These proteins include cytoskeletal and signaling proteins, metabolic enzymes, chaperones, and redox- and differentiation-related proteins. These results broaden our knowledge of potential signal transduction pathways that may lead to the development of new biomarkers and therapy targets.

Topics: Apoptosis; Cell Line, Tumor; Colon; Colonic Neoplasms; Deoxycholic Acid; Detergents; Epithelial Cells; Humans; Intestinal Mucosa; Nitroso Compounds; Proteins; Proteome

Deoxycholic acid (DCA), a secondary bile acid, has been implicated to promote colon cancer growth and progression. However, its molecular mechanisms are largely unknown. In this study, we investigated the effects of DCA on proliferation, migration, and invasiveness of colon cancer cells (HT-29).. HT-29 cells were incubated with either medium (control) only or DCA for 24-48 hours. Time courses of RT-PCR for vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1alpha mRNA expression, Western blotting for VEGF and matrix metalloproteinase (MMP)-9, zymography for MMP-9 activation, and wound-migration assay were determined after various concentrations of DCA (0-80 microM) treatment. Moreover, these experiments were reassessed after pretreatments (2-6 hours) with specific inhibitors of various signal pathways.. DCA enhanced HIF-1alpha mRNA expression, VEGF mRNA and VEGF protein expression, MMP-9 protein expression/activation, and cell migration ability in a dose-related manner. DCA-induced VEGF protein expression was inhibited by pretreatment with NS-398 (COX-2 inhibitor), PDTC (NF-kappaB inhibitor), or tauroursodeoxycholic acid (TUDC). DCA-induced cell migration ability was inhibited by pretreatment of GF109203X, a protein kinase C inhibitor. DCA-induced MMP-9 protein expression/activation was inhibited by pretreatment with SB203580, U0126, or PDTC.. DCA significantly upregulates invasive and angiogenic potentials of human colon cancer cells through multiple signal transduction pathways.

Topics: Cell Movement; Colonic Neoplasms; Deoxycholic Acid; HT29 Cells; Humans; Hypoxia-Inducible Factor 1; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Vascular Endothelial Growth Factor A

Environmental factors, including dietary fats, are implicated in colonic carcinogenesis. Dietary fats modulate secondary bile acids including deoxycholic acid (DCA) concentrations in the colon, which are thought to contribute to the nutritional-related component of colon cancer risk. Here we demonstrate, for the first time, that DCA differentially regulated the site-specific phosphorylation of focal adhesion kinase (FAK). DCA decreased adhesion of HCA-7 cells to the substratum and induced dephosphorylation of FAK at tyrosine-576/577 (Tyr-576/577) and Tyr-925. Tyrosine phosphorylation of FAK at Tyr-397 remained unaffected by DCA stimulation. Interestingly, we found that c-Src was constitutively associated with FAK and DCA actually activated Src, despite no change in FAK-397 and an inhibition of FAK-576 phosphorylation. DCA concomitantly and significantly increased association of tyrosine phosphatase ShP2 with FAK. Incubation of immunoprecipitated FAK, in vitro, with glutathione-S-transferase-ShP2 fusion protein resulted in tyrosine dephosphorylation of FAK in a concentration-dependent manner. Antisense oligodeoxynucleotides directed against ShP2 decreased ShP2 protein levels and attenuated DCA-induced FAK dephosphorylation. Inhibition of FAK by adenoviral-mediated overexpression of FAK-related nonkinase and gene silencing of Shp2 both abolished DCA's effect on cell adhesion, thus providing a possible mechanism for inside-out signaling by DCA in colon cancer cells. Our results suggest that DCA differentially regulates focal adhesion complexes and that tyrosine phosphatase ShP2 has a role in DCA signaling.

Topics: Bile Acids and Salts; Cell Adhesion; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Enzyme Activation; Focal Adhesion Protein-Tyrosine Kinases; Humans; Intracellular Signaling Peptides and Proteins; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Protein Tyrosine Phosphatases; Signal Transduction

Depending on their physico-chemical characteristics, bile acids can be potent inducers of apoptosis in colon cancer cells. This observation contrasts with bile acids being promoters of colorectal cancer carcinogenesis. Our recent observation of caspase activation in deoxycholate (DC)-treated colon cancer cell lines prompted us to analyze the mechanisms of bile acid-induced colon cancer cell death.. CD95 expression was correlated to DC-induced cell death in four colon cancer cell lines. Mitochondrial transmembrane potential (MTP) was determined in whole cells as well as in isolated mitochondria.. On 2 of the 4 human colon cancer cell lines investigated, no CD95 was detected. These data were supported by a lack of CD95 mRNA in those cell lines that did not express CD95 on their surface. The apoptotic response to bile acids did not correlate with CD95 receptor expression on the respective cell lines. Therefore, we analyzed the MTP after the addition of toxic bile acids. MTP was destabilized early after the addition of deoxycholate to SW480 cells. These data were confirmed in isolated mitochondria, which showed strong swelling after the addition of DC. Accordingly, release of cytochrome-c from the mitochondrial intermembrane space into the cytosol, indicating dissipation of the MTP, and subsequent caspase-3 cleavage were detectable as early as 3 min after the addition of DC.. In contrast to hepatocytes and hepatic carcinoma cell lines, DC induces apoptosis in colon cancer cell lines via a CD95 receptor-independent mechanism. Direct induction of the mitochondrial permeability transition by toxic bile acids is suggested as the apoptosis-inducing mechanism in colon cancer cells.

Topics: Apoptosis; Blotting, Western; Cell Line, Tumor; Colonic Neoplasms; Deoxycholic Acid; fas Receptor; Flow Cytometry; Gene Expression; Humans; In Vitro Techniques; Membrane Potentials; Microscopy, Fluorescence; Mitochondria; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

LT97 human colonic adenoma cells reflecting early premalignant genotype and growth characteristics have been posed to tumor promoting bile acids in order to identify marker genes that permit identification of tumor promoters in vitro. Physiologically relevant concentrations of desoxycholate (DOC) and chenodesoxycholate (CDC) upregulated expression of c-fos and COX-2 in a concentration- and time-dependent manner. Transient induction of c-fos was seen with the non-promoting taurodesoxycholate (TDOC) as well as DOC, however extended induction at 3 h was only achieved by DOC and CDC reaching 3-6-fold as compared to the control. Stimulation of COX-2 expression was completely specific for the tumor promoting analogs DOC and CDC. It was about 4-fold in the 80 microM DOC and CDC groups after 3 h and increased to 12- and 7-fold respectively after 6 h. Expression of VEGF was stimulated 4-5-fold in the tumor promoter (DOC and CDC) groups and about 2-fold in the non-promoting controls TDOC and GCDC. At later times the tumor promoter specific difference was lost. Our results show that all three genes are modulated in a tumor promoter dependent way and that their upregulation in LT97 adenoma cells can be used for in vitro testing of colon tumor promoters and chemopreventive compounds.

Topics: Adenoma; Bile Acids and Salts; Biomarkers, Tumor; Cell Line, Tumor; Chenodeoxycholic Acid; Colonic Neoplasms; Cyclooxygenase 2; Deoxycholic Acid; Dose-Response Relationship, Drug; Gene Amplification; Gene Expression Regulation, Neoplastic; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Isoenzymes; Membrane Proteins; Polymerase Chain Reaction; Prostaglandin-Endoperoxide Synthases; Proto-Oncogene Proteins c-fos; RNA; Taurodeoxycholic Acid; Time Factors; Tumor Necrosis Factor-alpha; Up-Regulation; Vascular Endothelial Growth Factor A

Apoptosis competence is central to the prevention of cancer. Frequency of apoptotic cells, after a sample of colonic tissue is stressed, can be used to gauge apoptosis competence and, thus, possible susceptibility to colon cancer. The gold standard for assessment of apoptosis is morphological evaluation, but this requires an experienced microscopist. Easier-to-use immunohistochemical markers of apoptosis, applicable in archived paraffin-embedded tissue, have been commercially developed. Potentially useful apoptosis markers include cleaved cytokeratin-18 (c-CK18), cleaved caspase-3 (c-cas-3), cleaved lamin A (c-lam-A), phosphorylated histone H2AX (gammaH2AX), cleaved poly(ADP ribose) polymerase (c-PARP), and translocation of apoptosis-inducing factor (AIF). When tissue samples from freshly resected colon segments were challenged ex vivo with the bile acid deoxycholate, approximately 50% of goblet cells became apoptotic by morphologic criteria. This high level of morphologic apoptosis allowed quantitative comparison with the usefulness and specificity of immunohistochemical markers of apoptosis. The antibody to c-CK18 was almost as useful and about as specific as morphology for identifying apoptotic colonic epithelial cells. Antibodies to c-cas-3, c-lam-A, and gammaH2AX, though specific for apoptotic cells, were less useful. The antibody to c-PARP, though specific for apoptotic cells, had low usefulness, and the antibody to AIF was relatively nonspecific, under our conditions.

Topics: Apoptosis; Biomarkers; Colon; Colonic Neoplasms; Deoxycholic Acid; Humans; Immunohistochemistry; In Vitro Techniques; Intestinal Mucosa

Mucin alterations are a common feature of colonic neoplasia, and alterations in MUC2 mucin have been associated with tumor progression in the colon. Bile acids have been linked to colorectal carcinogenesis and mucin secretion, but their effects on mucin gene expression in human colon carcinoma cells is unknown. Human colon carcinoma cells were treated chenodeoxycholate > ursodeoxycholate). Treatment with the putative chemopreventive agent curcumin, which decreased AP-1 activity, also decreased MUC2 transcription. Cotransfection with a dominant negative AP-1 vector decreased MUC2 transcription, confirming the significance of AP-1 in MUC2 induction by deoxycholate. Calphostin C, a specific inhibitor of protein kinase C (PKC), greatly decreased bile acid-induced MUC2 transcription and AP-1 activity, whereas inhibitors of MAP kinase had no effect.. Bile acids induced mucin expression in human colon carcinoma cells by increasing MUC2 transcription through a process involving MAP kinase-independent, PKC-dependent activation of AP-1.

Topics: Antineoplastic Agents; Chenodeoxycholic Acid; Cholagogues and Choleretics; Cholic Acids; Colonic Neoplasms; Curcumin; Deoxycholic Acid; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Humans; Mitogen-Activated Protein Kinases; Mucin-2; Mucins; Naphthalenes; Promoter Regions, Genetic; Protein Kinase C; RNA, Messenger; Transcription Factor AP-1; Transcription, Genetic; Transcriptional Activation; Tumor Cells, Cultured; Up-Regulation; Ursodeoxycholic Acid

Hydrophobic bile acids induce apoptosis in both colon cancer cells and hepatocytes. The mechanism by which colon cancer cells respond to bile acids is thought to be different from that of hepatocytes. Therefore, we investigated the characteristics of apoptosis in colon cancer cell line HCT116. Hydrophobic bile acids, i.e., deoxycholic acid (DCA), and chenodeoxycholic acid, induced apoptosis in HCT116 cells. Apoptotic indications were detectable at as early as 30 min and the extent increased in time- and concentration-dependent manners. SDS and a hydrophilic bile acid, cholic acid, did not induce apoptosis even at cytotoxic concentrations. Pretreatment with cycloheximide failed to inhibit apoptosis, suggesting that protein synthesis is not involved in the apoptotic response. Release of cytochrome c from mitochondria and activation of caspase-9 were detectable after 5 and 10 min, respectively, whereas remarkable activation of Bid was not detected. Ursodeoxycholic acid (UDCA) protected HCT116 cells from DCA-induced apoptosis but a preincubation period of > or =5 h was required. Nevertheless, UDCA did not inhibit cytochrome c release from mitochondria. Our results indicate that hydrophobic bile acids induce apoptosis in HCT116 cells by releasing cytochrome c from mitochondria via an undefined but specific mechanism, and that UDCA protects HCT116 cells by acting downstream of cytochrome c release.

Topics: Apoptosis; Caspase 9; Caspases; Colonic Neoplasms; Cytochromes c; Deoxycholic Acid; HCT116 Cells; Humans; Hydrophobic and Hydrophilic Interactions; Mitochondria; Ursodeoxycholic Acid

Deoxycholic acid (DCA) has been implicated in colonic carcinogenesis through effects mediated by protein kinase C (PKC) activation. By contrast, ursodeoxycholic acid (UDCA) is reported to reduce colon cancer incidence in ulcerative colitis. The aim of this study was to investigate whether UDCA modulated DCA-induced PKC isoenzyme translocation to its site of activity. HCT116 cells were treated with DCA, UDCA alone or pre-treated with UDCA followed by DCA. Analysis of translocation of endogenous and enhanced green fluorescent protein (EGFP) constructs of PKC isoenzymes was performed. Both DCA and phorbol myristate acetate (PMA) but not UDCA caused translocation of endogenous PKC alpha, epsilon and delta and transfected PKC beta1-, epsilon- and delta-EGFP from cytosol to plasma membrane, reflecting isoenzyme activation. Furthermore, UDCA inhibited DCA-induced translocation of PKC isoenzymes. Inhibition of DCA-induced PKC translocation may be a mechanism for UDCA-mediated chemoprevention of colon carcinogenesis.

Topics: Anticarcinogenic Agents; Blotting, Western; Cell Line, Tumor; Cell Shape; Colonic Neoplasms; Deoxycholic Acid; Green Fluorescent Proteins; Humans; Protein Kinase C; Tetradecanoylphorbol Acetate; Transfection; Ursodeoxycholic Acid

Secondary bile acids have been implicated as an important etiological factor in colorectal cancer. We investigated the effects of ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) on the growth and cytotoxicity in HT29 human colonic adenocarcinoma cells. Proliferation assay, cell cycle analysis and cell death characterization by bile acids were performed. Both UDCA and DCA reduced their proliferation rate of HT29 over 48 h in a concentration- and time-dependent manner compared with control cultures. In terms of cell cycle effects, however, UDCA induced G2/M arrest, while DCA induced G1 arrest in a concentration- and time-dependent manner. As for the effects of each bile acid on cell toxicity, UDCA induced early apoptosis and DCA induced both early apoptosis and necrosis. Bile acids play an important role in regulating cell survival and cell death in colon adenocarcinoma cells.

Topics: Adenocarcinoma; Apoptosis; Bile Acids and Salts; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Flow Cytometry; HT29 Cells; Humans; Time Factors; Ursodeoxycholic Acid

Secondary bile acids such as deoxycholic acid (DCA) are known to promote colorectal cancer (CRC). Increasing evidence suggests that DCA-induced signaling is mediated by activation of the epidermal growth factor receptor (EGFR). We have shown that activation of the EGFR induces up-regulation of cyclooxygenase 2, basolateral release of prostaglandins (PGs), and mitogenesis in a polarizing human colon cancer cell line, HCA-7. The purpose of this study was to determine the mechanism by which DCA activates EGFR in human polarizing CRC cell lines HCA-7 and HCT-8.. A primary, non-tumor-promoting bile acid (cholic acid [CA]) and a secondary, tumor-promoting bile acid, DCA, were added to the apical and basolateral compartment of polarized HCA-7 and HCT-8 cells. These cells were pretreated with monoclonal antibody 528, a monoclonal antibody that inhibits ligand binding to EGFR, or with WAY-022, a selective inhibitor of tumor necrosis factor-alpha converting enzyme/a disintegrin and metalloprotease-17 (TACE/ADAM-17), which cleaves amphiregulin (AR) to its mature, soluble form from the basolateral cell membrane. AR levels were measured in the apical and basolateral medium and cell lysates by radioimmunoassay. PGs were measured in the apical and basolateral medium by gas chromatography/mass spectrometry.. Basolateral delivery of DCA, but not CA, preferentially stimulated release of AR into the basolateral medium compared with cell lysates of polarized HCA-7 and HCT-8 cells. Basolateral delivery of DCA resulted in increased basolateral PGE2 levels (P < .05), and this effect was attenuated by pretreatment with monoclonal antibody 528 (P < .05). Inhibiting cell surface cleavage of AR with WAY-022 before DCA treatment reduced AR (P < .05) and PGE2 (P < .05) levels in the basolateral medium.. DCA, but not CA, results in compartment-specific, ligand-dependent activation of EGFR and subsequent increased basolateral PGE2 levels. The mechanism of DCA-induced EGFR activation is ligand-dependent and is controlled, at least in part, at the level of AR release from the basolateral cell membrane.

Topics: Amphiregulin; Bile Acids and Salts; Cell Line, Tumor; Cell Membrane; Cell Polarity; Cholic Acid; Colonic Neoplasms; Deoxycholic Acid; EGF Family of Proteins; ErbB Receptors; Glycoproteins; Humans; Intercellular Signaling Peptides and Proteins; Ligands; Radioimmunoassay

The development of apoptosis resistance appears to be an important factor in colon carcinogenesis. To gain an understanding of the molecular pathways altered during the development of apoptosis resistance, we selected three cell lines for resistance to induction of apoptosis by deoxycholate, an important etiologic agent in colon cancer. We then evaluated gene expression levels for 825 proteins in these resistant lines, compared with a parallel control line not subject to selection. Eighty-two proteins were identified as either over-expressed or under-expressed in at least two of the resistant lines, compared with the control. Thirty-five of the 82 proteins (43%) proved to have a known role in apoptosis. Of these 35 proteins, 21 were over-expressed and 14 were under-expressed. Of those that were over-expressed 18 of 21 (86%) are anti-apoptotic in some circumstances, of those that were under-expressed 11 of 14 (79%) are pro-apoptotic in some circumstances. This finding suggests that apoptosis resistance during selection among cultured cells, and possibly in the colon during progression to cancer, may arise by constitutive over-expression of multiple anti-apoptotic proteins and under-expression of multiple pro-apoptotic proteins. The major functional groups in which altered expression levels were found are post-translational modification (19 proteins), cell structure (cytoskeleton, microtubule, actin, etc.) (17 proteins), regulatory processes (11 proteins) and DNA repair and cell cycle checkpoint mechanisms (10 proteins). Our findings, overall, bear on mechanisms by which apoptosis resistance arises during progression to colon cancer and suggest potential targets for cancer treatment. In addition, assays of normal-appearing mucosa of colon cancer patients, for over- or under-expression of genes found to be altered in our resistant cell lines, may allow identification of early biomarkers of colon cancer risk.

Topics: Apoptosis; Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Detergents; Drug Resistance, Neoplasm; Humans; Neoplasm Proteins; Proteomics; Tumor Cells, Cultured

Colorectal cancer is often lethal when invasion and/or metastasis occur. Tumor progression to the metastatic phenotype is mainly dependent on tumor cell invasiveness. Secondary bile acids, particularly deoxycholic acid (DCA), are implicated in promoting colon cancer growth and progression. Whether DCA modulates beta-catenin and promotes colon cancer cell growth and invasiveness remains unknown. Because beta-catenin and its target genes urokinase-type plasminogen activator receptor (uPAR) and cyclin D1 are overexpressed in colon cancers, and are linked to cancer growth, invasion, and metastasis, we investigated whether DCA activates beta-catenin signaling and promotes colon cancer cell growth and invasiveness. Our results show that low concentrations of DCA (5 and 50 microM) significantly increase tyrosine phosphorylation of beta-catenin, induce urokinase-type plasminogen activator, uPAR, and cyclin D1 expression and enhance colon cancer cell proliferation and invasiveness. These events are associated with a substantial loss of E-cadherin binding to beta-catenin. Inhibition of beta-catenin with small interfering RNA significantly reduced DCA-induced uPAR and cyclin D1 expression. Blocking uPAR with a neutralizing antibody significantly suppressed DCA-induced colon cancer cell proliferation and invasiveness. These findings provide evidence for a novel mechanism underlying the oncogenic effects of secondary bile acids.

Topics: beta Catenin; Biological Assay; Cadherins; Cell Line; Colonic Neoplasms; Cyclin D1; Cytoskeletal Proteins; Deoxycholic Acid; Gene Expression Regulation; Humans; Neoplasm Invasiveness; Phosphorylation; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator; RNA, Small Interfering; Signal Transduction; Trans-Activators; Tyrosine; Urokinase-Type Plasminogen Activator

Deoxycholic acid (DCA) has been appeared to be an endogenous colon tumor promoter. In this study, we investigated whether DCA induces nuclear factor-kappa B (NF-kappa B) activation and IL-8 expression, and tauroursodeoxycholic acid (TUDC) inhibits this signaling in HT-29 cells.. After DCA treatments, time courses of NF-kappa B binding activity were determined by electrophoretic mobility shift assay (EMSA). Also, we performed Western blotting of I kappa B alpha to confirm NF-kappa B activation. Time and concentration courses of DCA-induced secretion of IL-8 were measured with ELISA in supernatants of cultured media from the cells. To evaluate the role of NF-kappa B, IL-8 levels were assessed after pretreatment with using phosphorothioate-modified anti-sense oligonucleotides (ODN). Moreover, DCA-induced secretions of IL-8 were measured after pretreatment with TUDC.. DCA dose-dependently induced prominent NF-kappa B binding complexes from 30 min to 8 hr and degradation of I kappa B alpha. The secretions of IL-8 were increased with DCA (50-200 micro M) treatment in a time and dose-dependent manner. Pre-incubation of the cells with TUDC (0.1-10 micro M) for 2 hours caused significant decreases in DCA induced IL-8 secretion. However, transient transfection using p50 or p65 AS-ODN showed no effect on IL-8 secretion.. DCA may play as a colonic tumor promoter through anti-apoptotic effect of NF-kappa B activation and IL-8 expression, and DCA-induced NF-kappa B independent IL-8 expression is inhibited by TUDC.

Topics: Blotting, Western; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; HT29 Cells; Humans; Interleukin-8; NF-kappa B; Oligonucleotides, Antisense; Signal Transduction; Taurochenodeoxycholic Acid; Transcriptional Activation

Topics: Colon; Colonic Neoplasms; Deoxycholic Acid; Humans; Intestinal Mucosa; Taurocholic Acid

The ability of non-genotoxic colon carcinogens to induce DNA hypomethylation was evaluated. Administering 0, 0.2 and 0.4 mg/kg of 5-aza-2'-deoxycytidine to female mice for 5 days resulted in a dose-related decrease in 5-methylcytosine in colon DNA. Rutin (3.0 mg/kg) and five bile acids (4.0 mg/kg) were administered in the diet to male F344 rats for 14 days. Rutin and four bile acids that promote colon cancer, deoxycholic acid, chenodeoxycholic acid, cholic acid and lithocholic acid caused DNA hypomethylation, while ursodeoxycholic acid that prevents colon cancer did not. Bromodichloromethane (BDCM) was administered to male F344 rats and B6C3F1 mice by gavage at 0, 50 and 100 mg/kg or in their drinking water at 0, 350 and 700 mg/l for up to 28 days. In rats, BDCM decreased DNA methylation, being more effective when administered by gavage, correlating to its greater carcinogenic potency by this route. In mice, BDCM did not decrease DNA methylation, corresponding to its lack of carcinogenic activity in the colon of this species. In summary, the ability of non-genotoxic colon carcinogens to cause DNA hypomethylation correlated with their carcinogenic activity in the colon.

Topics: Animals; Azacitidine; Carcinogens; Chenodeoxycholic Acid; Cholic Acid; Colon; Colonic Neoplasms; Decitabine; Deoxycholic Acid; DNA; DNA Methylation; Dose-Response Relationship, Drug; Female; Lithocholic Acid; Male; Mice; Rats; Rats, Inbred F344; Rutin; Time Factors

Aberrant crypt foci, precursors of colonic adenoma, are frequently positive for glutathione-S-transferase P1-1. Because deoxycholic acid is an apoptosis-inducing xenobiotic in the colon, we examined the possibility that aberrant crypt foci, through the cytoprotecting function of glutathione-S-transferase P1-1, resist deoxycholic acid-induced apoptosis, thereby surviving to become adenomas and subsequently cancer.. Glutathione-S-transferase P1-1 or cyclooxygenase-2 expression and the percentage of apoptotic cells in aberrant crypt foci were examined by immunohistochemistry and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, respectively. Glutathione-S-transferase P1-1 was transfected into colon cancer cells (M7609) and human lung fibroblasts, and deoxycholic acid-induced apoptosis was evaluated by a dye-uptake assay and flow cytometry. Binding of deoxycholic acid to glutathione-S-transferase P1-1 was analyzed by circular dichroism and immunoprecipitation. Caspase activities were determined by colorimetric protease assay, and sulindac binding to glutathione-S-transferase P1-1 was determined by inhibition assay of glutathione-S-transferase P1-1 activity.. Aberrant crypt foci showed positive immunostaining for glutathione-S-transferase P1-1 but negative staining for cyclooxygenase-2. The percentage of apoptotic cells in aberrant crypt foci was significantly lower than in healthy epithelium, and the difference became more apparent with deoxycholic acid treatment. The impaired sensitivity of aberrant crypt foci to deoxycholic acid was restored by the glutathione-S-transferase P1-1-specific inhibitor gamma-glutamyl-S-(benzyl)cysteinyl-R-phenylglycine diethylester. By transfection of glutathione-S-transferase P1-1, M7609 cells became more resistant to deoxycholic acid-induced apoptosis than mock transfectants. Direct binding of glutathione-S-transferase P1-1 to deoxycholic acid was proven by circular dichroism and by immunoprecipitation. The aberrant crypt foci in adenoma patients treated with sulindac, which was shown to bind to glutathione-S-transferase P1-1, underwent apoptosis in 4 days and mostly regressed in 2-3 months.. Glutathione-S-transferase P1-1 protects aberrant crypt foci from deoxycholic acid-induced apoptosis and may play a pivotal role in early colon carcinogenesis.

Topics: Adenoma; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Colonic Neoplasms; Cyclooxygenase 2; Deoxycholic Acid; Detergents; Enzyme Inhibitors; Fibroblasts; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Glutathione; Glutathione Transferase; Humans; Intestinal Mucosa; Isoenzymes; Lung; Membrane Proteins; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Sulindac; Transfection

It has been suggested that the bile acids in the feces act as a promoter of colon cancer. Among the bile acids, deoxycholic acid (DCA), which is one kind of the secondary bile acid, is said to have strong influence. DCA/cholic acid (CA) ratio in feces is also said to have a diagnostic significance in colon cancer. With this in mind, we created a CA and DCA's monoclonal antibody (MoAb) to measure them through the enzyme linked immunosorbent assay (ELISA) method. Using these MoAb, we were able to measure CA and DCA concentrations with low cross-reaction to other bile acids compared with the method with polyclonal antibody (PoAb). We measured CA and DCA concentrations and calculated the DCA/CA ratios in healthy subjects and patients with colon cancer. All subjects had been screened for colon cancer. We then compared the healthy subjects, the cancer patients before surgery and the same cancer patients after surgery. Cancer patients after surgery had significantly low DCA/CA ratios compared to before surgery, whereas there was no significant difference between healthy subjects and the pre-operative colon cancer patients.

Topics: Antibodies, Monoclonal; Cholic Acid; Colonic Neoplasms; Deoxycholic Acid; Enzyme-Linked Immunosorbent Assay; Feces; Humans

Epidemiologic studies indicate that environmental (smoking) and dietary factors (high fat) contribute to carcinogenesis in many organ systems. The aim of our study was to test the hypothesis that nicotine, a component of cigarette smoke, and sodium deoxycholate (NaDOC), a cytotoxic bile salt that increases in concentration in the gastrointestinal tract after a high fat meal, induce similar cellular stresses and that nicotine may enhance some of the NaDOC-induced stresses. We found that nicotine, at 0.8 microM, the very low sub-micromolar level occurring in the tissues of smokers: (1). increases oxidative stress; (2). activates NF-kappaB, a redox-sensitive transcription factor; (3). activates the 78 kD glucose regulated protein promoter, an indication of endoplasmic reticulum stress; (4). induces apoptosis; (5). enhances the ability of NaDOC to activate the 153 kD growth arrest and DNA damage promoter, an indication of increased genotoxic stress; and (6). enhances the ability of NaDOC to activate the xenobiotic response element. Our findings have applicability to G.I. cancer, in general, since smoking is a risk factor in the development of esophageal, pancreatic, gastric and colon cancer, and these cancers are also promoted by bile acids.

Topics: Apoptosis; Carrier Proteins; CCAAT-Enhancer-Binding Proteins; Chloramphenicol O-Acetyltransferase; Colonic Neoplasms; Deoxycholic Acid; DNA Damage; Endoplasmic Reticulum Chaperone BiP; Enzyme-Linked Immunosorbent Assay; Heat-Shock Proteins; Humans; Membrane Potentials; Molecular Chaperones; Mutagens; NF-kappa B; Nicotine; Oxidative Stress; Promoter Regions, Genetic; Transcription Factor CHOP; Transcription Factors; Tumor Cells, Cultured; Xenobiotics

High fecal deoxycholate levels may promote colonic cancer. Phospholipids protect against bile salt-induced cytotoxicity. We therefore aimed to examine whether the dietary phospholipid sphingomyelin could decrease hyperproliferation induced by deoxycholate. In CaCo2 cells, hyperproliferation (by bromodeoxyuridine assay), phosphorylation state of cellular proteins, and apoptosis with concomitant caspase-3 activity were evaluated after incubation with 50-500 microM deoxycholate, with or without sphingomyelin. At 2 and 4 hr of incubation, deoxycholate induced dose-dependent apoptosis, with concomitant caspase-3 activation. At 16 hr, apoptosis had decreased markedly, but there was dose-dependent hyperproliferation (with changed phosphorylation status of cellular proteins) at this time point. Sphingomyelin dose-dependently reduced deoxycholate-induced apoptosis and hyperproliferation. In conclusion, sphingomyelin reduces deoxycholate-induced hyperproliferation and apoptosis. These findings may have implications for colonic cancer prevention by dietary modification.

Topics: Apoptosis; Caco-2 Cells; Caspase 3; Caspases; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Enzyme Precursors; Humans; Sphingomyelins; Time Factors

Deoxycholate, a bile salt present at high levels in the colonic lumen of individuals on a high-fat diet, is a promoter of colon cancer. Deoxycholate also causes DNA damage. BRCA-1 functions in repair of DNA and in induction of apoptosis. We show that, when cultured cells of colonic origin are exposed to deoxycholate at different concentrations, BRCA-1 expression is induced at a low noncytotoxic concentration (10 microM) but is strongly inhibited at higher cytotoxic concentrations ( > or =100 microM). Indication of phosphorylation of BRCA-1 by deoxycholate (100 microM) at a lower dose was seen by Western blot analysis, whereas, at a higher dose, deoxycholate (200 and 300 microM) caused a complete loss of BRCA-1 expression. We show that BRCA-1 is substantially lower in colon adenocarcinomas from five patients compared with associated non-neoplastic colon tissue from the same patients, suggesting that the loss of BRCA-1 expression contributes to the malignant phenotype. In the non-neoplastic colon tissue, BRCA-1 was localized to the nongoblet cells. Our results imply that reduced expression of BRCA-1 may be associated with carcinoma of the colon.

Topics: Adenocarcinoma; Adult; Aged; Apoptosis; Blotting, Western; Carcinogens; Cell Survival; Colonic Neoplasms; Deoxycholic Acid; Detergents; DNA Damage; Epithelial Cells; Gene Expression; Genes, BRCA1; Humans; Middle Aged; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured

The EphA2 receptor protein tyrosine kinase gene has been shown to be over-expressed or functionally altered in a number of human tumors, including colon cancer, but little is known about the regulation of this new oncoprotein. In order to explore the mechanism of EphA2 up-regulation in cancer cells, we examined the change of expression of EphA2 gene induced by deoxycholic acid (DCA) and elucidated its possible pathways in human colon cancer cells.. Western blot and RT-PCR were used to assess the protein expression and messenger RNA in several colon cancer cell lines, which harbor various p53 status. The inhibition study to interfere the MAPK pathway was performed by using various chemicals and by transfecting dominant negative mutant plasmids.. Up-regulation of EphA2 induced by DCA was observed in a dose- and time-dependent fashion both in mRNA and protein levels. This regulation is constant regardless of p53 status including wild, mutant or knocked out in the colon cell lines used. This induction was in part blocked by either erk1/2 inhibitors or dominant negative mutants erk1/2 plasmids.. These results suggest that DCA induced up-regulation of EphA2 in colon cancer cells is due to activation of erk1/2 cascade, and is p53-independent. Taken together with the roles of EphA2 and DCA in tumorigenesis, which have been independently reported, our observation will provide a new mechanistic basis of DCA commitment in carcinogenesis.

Topics: Blotting, Western; Carcinoma; Cell Line, Tumor; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Humans; Mitogen-Activated Protein Kinases; Receptor, EphA2; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Time Factors; Tumor Suppressor Protein p53; Up-Regulation

Hydrophobic bile acids such as deoxycholate are known tumor promoters in the gastrointestinal tract. We have previously shown that deoxycholate induces apoptosis in colon epithelial cells and that these cells can be made resistant to deoxycholate-induced apoptosis. We now show that the nitric oxide synthase/nitric oxide/guanylate cyclase/cyclic guanosine monophosphate/cGMP-activated protein kinase (NOS/NO/GC/cGMP/PKG) signaling module contributes, in part, to the observed resistance of the cultured DOC-resistant colon epithelial cells (HCT-116R) using pharmacological inhibitors/antagonists (NS2028, Rp-8pCPT-cGMP, KT5823) of members of this signaling module. A novel finding from this study is the caspase-6 mediated cleavage of guanylate cyclase alpha 1 during deoxycholate-induced apoptosis of deoxycholate-sensitive HCT-116SA cells and the absence of guanylate cyclase alpha 1 cleavage in deoxycholate-treated HCT-116R resistant cells using Western blot analyses. This cleavage was specific to caspases as lysosomal, proteasomal, serine protease, cathepsin and calpain inhibitors failed to prevent the cleavage, whereas a general caspase inhibitor and a specific caspase-6 inhibitor did prevent guanylate cyclase alpha 1 cleavage.

Topics: Animals; Apoptosis; Caspase 6; Caspases; Colonic Neoplasms; Cyclic GMP; Deoxycholic Acid; Enzyme Inhibitors; Epithelial Cells; Guanylate Cyclase; Humans; Nitric Oxide Donors; Nitric Oxide Synthase; Reactive Oxygen Species; Tumor Cells, Cultured

Micellar electrokinetic capillary chromatography (MEKC) with laser-induced fluorescence detection is used for the analysis of three classes of aminophospholipids: phosphatidylethanolamine (PE), phosphatidylserine (PS), and lysophosphatidylethanolamine (LPE) molecular species. 3-(2-Furoyl) quinoline-2-carboxaldehyde (FQ), a fluorogenic dye, was employed for labeling of these phospholipids. The FQ-labeled lipid species were then separated by sodium deoxycholate MEKC modified with methyl-beta-cyclodextrin. Baseline resolution of each class of phospholipids was achieved within 7 min. The migration time in each class increased with the carbon number of their side aliphatic chain. Separation efficiencies of approximately 3x10(5) plates were observed for most of these species. Concentration detection limits (3 sigma) were from 10(-9) to 10(-10) M for PE and LPE species and from 10(-8) to 10(-9) M for PS species. The relative standard deviations for migration time and peak area were less than 0.9% and 4.5%, respectively, for seven PE species. This method was applied to the separation of PE isolated from HT29 human colon cancer cells and roughly 30 PE species were resolved.

Topics: beta-Cyclodextrins; Chromatography, Micellar Electrokinetic Capillary; Colonic Neoplasms; Cyclodextrins; Deoxycholic Acid; Electrophoresis, Capillary; Fluorescent Dyes; Fluorometry; Humans; Indicators and Reagents; Lasers; Lysophospholipids; Phosphatidylethanolamines; Phosphatidylserines; Phospholipids; Sensitivity and Specificity; Tumor Cells, Cultured

Bile acids are believed to play a role in the etiology of colorectal cancer, and high fecal excretion of secondary bile acids was correlated with increased incidence of colon cancer. Recently, it was also reported that there is an increase in plasma of the secondary bile acid, deoxycholic acid in men with colorectal adenomas. Since deoxycholic acid is formed in the colon and absorbed into the portal systemic circulation, it was suggested that the blood concentration of this bile acid reflects the level of exposure of colonic cells to deoxycholic acid. The objective of this study was to investigate whether plasma deoxycholic acid level represents the fecal content of this bile acid in several animal species with different bile acid composition and deoxycholic acid contribution to the bile acid pool. Eight rabbits, hamsters, guinea pigs, and rats were used in this study. Blood samples and feces were collected on days 1, 3, 5 and 7. Bile samples were obtained only on day 7. The plasma, fecal and biliary bile acids were analyzed by gas chromatography-mass spectrometry. Bile acid composition and deoxycholic acid content varied greatly between the animal species studied. There was a variation in the concentration of total bile acids in the plasma and feces obtained at different times during the experiments, however, the bile acids profile remained constant throughout the study. The data obtained shows that although plasma bile acid profile was not similar to fecal bile acids profile, however, there was a significant correlation between the level of plasma and fecal deoxycholic acid. Plasma deoxycholic acid concentration might be a reliable biomarker for the degree of exposure of colon cells to this bile acid, and may be useful in further studies on the role of secondary bile acids in colon carcinogenesis.

Topics: Animals; Bile; Bile Acids and Salts; Colonic Neoplasms; Cricetinae; Deoxycholic Acid; Feces; Guinea Pigs; Male; Mesocricetus; Rabbits; Rats; Rats, Sprague-Dawley; Species Specificity

Topics: Animals; Bile Acids and Salts; Colonic Neoplasms; Cyclooxygenase 2; Deoxycholic Acid; Dose-Response Relationship, Drug; Enzyme Induction; Feces; Humans; Isoenzymes; Membrane Proteins; Prostaglandin-Endoperoxide Synthases; Tumor Cells, Cultured

Deoxycholic acid has long been attributed as a tumour promoter in the colon. It exerts its growth-related actions in a phorbol ester-like manner, by stimulating protein kinase C. The aim of this study was to investigate the effect of deoxycholic acid on proliferation and apoptosis in the colon, by exposing colon cancer cells to it in increasing concentrations.. Human colon cancer cells (Caco-2 and HT-29) were treated with deoxycholate or its two structural isomers, 3-beta-12-alpha-dihydroxy-5-beta-cholan-24-oic acid and 3-alpha-12-beta-dihydroxy-5-beta-cholan-24-oic acid. Proliferation was evaluated by cell counting, and apoptosis by estimating percentage cell survival and assessment of nuclear morphology.. Within the concentration range of up to 20 microM, deoxycholate stimulated growth of both human colon cancer cell lines. Its growth-promoting effect was abolished after inhibition of protein kinase C. At concentrations above 100 microM, deoxycholate induced apoptosis in both cell lines. Epimers of deoxycholate were significantly less potent in stimulating growth.. Low-dose deoxycholate stimulates colon cancer cell proliferation while > 100 micromol L(-1) of this secondary bile acid induces apoptosis in colon cancer cells. Deoxycholate might promote the likelihood of malignant transformation by increasing epithelial cell turnover in the colon.

Topics: Apoptosis; Bile Acids and Salts; Caco-2 Cells; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Detergents; HT29 Cells; Humans; Intestinal Mucosa; Protein Kinase C

Increased intestinal bile acids as a possible consequence of a high fat/meat, low fiber diet are believed to play an important role in the formation of colon cancer. Interactions of bile salts particularly secondary bile acids with different cell components including DNA may contribute to carcinogenesis. To further investigate DNA damage by bile salts, we assessed the effects of a bile salt mixture containing deoxycholate and chenodeoxycholate on base hydroxylation in Chelex-treated DNA from calf thymus as a model of human colonic mucosal DNA in the presence and absence of reactive oxygen metabolites (ROM).. Chelex-treated DNA from calf thymus (to remove residual iron impurities) was incubated with different bile salt concentrations (4 microM, 4.0 mM) (20.0% deoxycholate, 21.0% chenodeoxycholate) in the presence and absence of an OH generating system (25 microM FeCl3, 50 microM H2O2, 100 microM nitrilotriacetic acid) for 18 h (37 degrees C). After hydrolyzation, lyophilization and derivatization hydroxylated DNA bases were characterised and quantitated with gas chromatography-mass spectrometry (GS-MS) and SIM analysis. Two concentration ranges of bile salts were used, micromolar concentrations being present in plasma, millimolar in the gut lumen.. In the absence of ROM Chelex-treated DNA preparations contain only small amounts of hydroxylated base products. Bile salts at 4.0 mM significantly increased the amounts of 5-OH uracil and cis-thymine glycol. In the presence of ROM bile salts at 4.0 microM increased the production of 8-OH adenine and 8-OH guanine whereas bile salts at 4.0 mM inhibited ROM-induced base hydroxylation.. In the absence of ROM millimolar concentrations of a bile salt mixture with deoxycholate and chenodeoxycholate increase basal (spontaneous) DNA hydroxylation, whereas, they are without effects at micromolar concentrations. In the presence of ROM micromolar concentrations enhance oxidative DNA damage and millimolar concentrations were inhibitory. These results support the view that bile acids may cause oxidative DNA damage depending on their concentrations and the surrounding conditions both directly (enhancement of basal hydroxylation) and indirectly (enhancement of ROM-induced hydroxylation).

Topics: Adenine; Animals; Cattle; Chenodeoxycholic Acid; Colon; Colonic Neoplasms; Deoxycholic Acid; DNA; DNA Damage; Gas Chromatography-Mass Spectrometry; Gastrointestinal Agents; Guanine; Humans; Hydroxylation; Intestinal Mucosa; Models, Chemical; Reactive Oxygen Species; Salicylates; Thymus Gland

The bile acid deoxycholic acid (DCA) is a known tumor promoter and it has been suggested that DCA-induced apoptosis plays an important role in colon tumor development. In this study we have characterized the capacity of DCA to stimulate mitogen-activated protein kinase (MAPK) activity and examined the effect that MAPK activity had on DCA-induced apoptosis. Analysis of MAPK activity in DCA-treated HCT116 cells using phosphorylation-specific antibodies and in vitro kinase assays indicated that both the extracellular signal-regulated kinase (ERK) and p38 MAPK (p38), but not the c-Jun N-terminal kinase (JNK), were activated. Using pharmacological inhibitors we determined that only ERK could influence DCA cytotoxicity and that elevated ERK activity could suppress DCA-induced apoptosis. This observation was confirmed genetically. Suppressing ERK activity by overexpressing a dominant negative form of the ERK MAP kinase resulted in increased sensitivity to DCA-induced apoptosis whereas elevated ERK activity artificially produced by overexpression of the wild-type ERK kinase blunted DCA-induced apoptosis. Taken together, our results suggest that DCA can stimulate pro-apoptotic and anti-apoptotic signaling pathways and that sensitivity to DCA-induced apoptosis can be modulated by the ERK MAP kinase.

Topics: Apoptosis; Colonic Neoplasms; Deoxycholic Acid; Down-Regulation; Enzyme Activation; Enzyme Inhibitors; Flavonoids; Humans; JNK Mitogen-Activated Protein Kinases; MAP Kinase Kinase 4; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Transfection; Tumor Cells, Cultured

Diets rich in fat result in higher concentrations of secondary bile acids or their salts in the colon, which may adversely affect cells of the colonic epithelium. Because secondary bile acids are thought to be genotoxic, exposing colon epithelial cells to secondary bile acids may induce DNA damage that might lead to apoptosis. The requirement for the p53 tumor suppressor gene in such events is unknown. In particular, the effects of secondary bile acids on colon epithelial cells having different p53 tumor suppressor gene status have not been examined. Therefore, HCT-116 and HCT-15 human colon adenocarcinoma cells, which express the wild-type and mutant p53 genes, respectively, were exposed to physiological concentrations of deoxycholate. The cells were then analyzed for evidence of DNA damage and apoptosis. After 2 h of incubation with 300 microM deoxycholate, both cell lines had greater levels of single-strand breaks in DNA as assessed by the comet assay. After 6 h of exposure to deoxycholate, HCT-116 and HCT-15 cells showed morphological signs of apoptosis, i.e., membrane blebbing and the presence of apoptotic bodies. Chromatin condensation and fragmentation were also seen after staining DNA with 4',6-diamidino-2-phenylindole. Other apoptotic assays revealed greater binding of annexin V-fluorescein isothiocyanate, as well as greater post-enzymatic labeling with dUTP-fluorescein isothiocyanate, by both cell lines exposed to deoxycholate. These data suggest that deoxycholate caused DNA damage in colon epithelial cells that was sufficient to trigger apoptosis in a p53-independent manner.

Topics: Adenocarcinoma; Apoptosis; Colonic Neoplasms; Comet Assay; Deoxycholic Acid; DNA Damage; Epithelial Cells; Genes, p53; Humans; In Situ Nick-End Labeling; Microscopy, Fluorescence; Mutation; Staining and Labeling; Tumor Cells, Cultured

Bile acids, principally deoxycholic acid (DCA), have been implicated in the promotion of colon tumorigenesis in both animals and humans. Increasing evidence suggests that bile acids may exert their tumor promoting activity by modulating intracellular signaling and altering gene expression. In this study we have investigated the effect of bile acids on the tumor suppressor p53 using the human colon tumor cell line HCT116, which retains the wild-type p53 gene and functional p53 signaling in response to DNA damage. We found that exposure of the cells to elevated concentrations of DCA suppressed accumulation of p53 protein as well as p53 transactivation and impaired the p53 response of the cells to DNA damaging agents, such as ionizing radiation. Neither ursodeoxycholic acid, a putative chemopreventive agent, nor cholic acid, which is biologically inert, had any effect on p53 protein level and transactivation activity. Further examination revealed that instead of inhibition, DCA induced p53 mRNA in a dose-dependent manner, indicating that the inhibitory effect of DCA on p53 protein is mediated by a post-transcriptional mechanism. Both lactacystin, a specific inhibitor of the 26S proteasome, and leptomycin B, a specific inhibitor of the nuclear export protein CRM1, could block the effect that DCA had on p53 protein levels, suggesting that DCA suppressed p53 by stimulating the process of proteasome-mediated degradation of p53. Significantly, blocking extracellular signal-regulated kinase (ERK) signaling, but not protein kinase C (PKC), blunted suppression by DCA of p53 protein levels and transactivation activity, suggesting that DCA suppressed p53, in part, by stimulating the ERK signaling pathway. Both ERK and PKC signaling have been previously demonstrated to be stimulated by DCA. These results suggest a novel signaling mechanism of bile acids that may play an important role in colon tumor promotion mediated by bile acids.

Topics: Carcinogens; Colonic Neoplasms; Cysteine Endopeptidases; Deoxycholic Acid; Down-Regulation; Fibroblasts; Gene Expression Regulation, Neoplastic; Genes, p53; Humans; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Multienzyme Complexes; Nuclear Proteins; Phosphorylation; Proteasome Endopeptidase Complex; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-mdm2; Transcription, Genetic; Transcriptional Activation; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Fisher-344 rats, whose ileum or jejunum had been surgically removed to change the influx of bile acids into the colon, were intraperitoneally administered with azoxymethane and fed on a diet containing deoxycholate for 39 weeks to induce colon cancer. Fecal bile acids in the ileum-resected group were 1.5-times and serum bile acids were about half of those in the jejunum-resected group. As a result, the incidence and number of tumors were higher in the ileum-resected group. In the total of 59 colon tumors (40 were in the ileum-resected group and 19 in the jejunum-resected group), 56 were carcinomas, including two well-differentiated invasive and two mucinous carcinomas found in the ileum-resected rats. However, only three carcinomas, two invasive and one non-invasive, had the K-ras mutation. These results demonstrate that the K-ras mutation was not essentially involved in deoxycholate-promoted colon carcinogenesis.

Topics: Animals; Azoxymethane; Carcinogens; Carcinoma; Colonic Neoplasms; Deoxycholic Acid; Diet; Genes, ras; Mutation; Polymorphism, Single-Stranded Conformational; Rats; Reverse Transcriptase Polymerase Chain Reaction

Deoxycholic acid and other secondary bile acids have long been considered tumour promoters in the colon. However, their effect on cell migration, known to play an important role in colon carcinogenesis, has not been studied so far.. To investigate the possible effects of deoxycholic acid on colon cancer-cell migration in culture.. Human colon carcinoma cells (Caco-2) were seeded on basement membrane matrix. To evaluate replication-blocked cell migration, we wounded confluent monolayers of cells with a sterile scalpel, and inhibited cell replication with mitomycin C. Immediately after wounding, the cells were exposed to 0-100 micromol/l deoxycholic acid. Migration over 72 h was monitored using a phase contrast microscope.. Replication-blocked migration was stimulated by deoxycholic acid in a dose-dependent manner, with the maximum effect at 20 micromol/l deoxycholic acid. Enhancement of migration rate was unaffected by immunoneutralization of transforming growth factor beta (a known migration-promoting peptide). However, specific inhibition of protein kinase C markedly inhibited deoxycholic acid-induced Caco-2 cell migration.. In addition to its well-established role in the enhancement of proliferation, deoxycholic acid also stimulates colon cancer-cell migration along the basement membrane matrix. The mechanism of this stimulation is likely to involve protein kinase C. Deoxycholic acid-stimulated migration might additionally contribute to the tumour-promoting effects of secondary bile acids in the colon.

Topics: Caco-2 Cells; Cell Division; Cell Movement; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Humans; Mitomycin; Protein Kinase C; Transforming Growth Factor beta; Tumor Cells, Cultured

The response of Escherichia coli to genotoxic agents involves the triggering of a complex system of genes known as the SOS response. In E. coli PQ37, a test organism used for the assessment of genotoxicity, lacZ, the beta-galactosidase gene is placed under the control of sfiA, one of the SOS genes through an operon fusion. The induction of beta-galactosidase activity, when the organism is exposed to genotoxic agents, is an indirect measure of the genotoxic activity of the test compound. Incubation of E. coli PQ37 with either 4-nitroquinoline oxide (4-NQO) or one of the fecal mutagens, fecapentaene-12 or -14 (F-12 or F-14) in the presence of sodium taurocholate or sodium deoxycholate resulted in a significant enhancement of induction of beta-galactosidase activity. The molecular mechanisms of 4-NQO-induced mutagenesis in E. coli are similar to those of the effects of UV light in which both replication-dependent and repair-dependent pathways of mutagenesis exist. Since E. coli PQ37 is excision-repair-deficient, alternate pathways are involved in this system. Bile salts by themselves do not trigger the SOS response, and hence their role in enhancing the SOS-inducing potency of mutagens may involve the potentiation of the cleavage-inactivation of lexA (repressor of SOS) by the protein product of the SOS-controlled gene, recA. The potentiating effect of bile salts on the fecal mutagens, F-12 and F-14, has implications in their suspected role in colon carcinogenesis associated with high-fat, low-fiber diets.

Topics: 4-Nitroquinoline-1-oxide; Alkaline Phosphatase; Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Drug Synergism; Escherichia coli; Lithocholic Acid; Mutagens; Polyenes; SOS Response, Genetics; Taurocholic Acid; Ultraviolet Rays

Deoxycholic acid (DCA) has long been implicated as tumour-promoting agent in the colon. Polyamines are necessary for cell proliferation, they are accumulated in high amounts in colon cancer cells, and their concentrations in the colonic lumen can reach millimolar levels. The aim of this study was to investigate the effects of physiological DCA concentrations on proliferation and polyamine content in human colon cancer cells (Caco-2) in culture. Over an initial 48 h in culture, DCA stimulated Caco-2 cell proliferation rate three-fold, reaching a maximum with 20 microM DCA. DCA-induced increases in ornithine decarboxylase (ODC) activity corresponded to peak proliferation rates, occurring only during the initial 48 h of cell proliferation. Treatment with low-dose DCA resulted in a two-fold increase in putrescine uptake, first noted after 2 days in culture, but persisting until the cells became confluent (day 5). Both basal and DCA-stimulated putrescine uptake in Caco-2 cells were saturable. Kinetic analysis of the uptake data showed that DCA-stimulated putrescine uptake was due to an increase in the capacity of the putative putrescine transporter, without changes in its affinity, therefore implying an increased number of putrescine transporters in the cell membrane, without change in their structure.

Topics: Caco-2 Cells; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Humans; Kinetics; Ornithine Decarboxylase; Polyamines; Putrescine; Time Factors; Up-Regulation

The insoluble 'high-molecular-weight' fraction (HMF) centrifugally separable after digestion of soy protein isolate with a microbial protease of the exo-type, of which about a quarter is regarded as an indigestible 'resistant protein,' was examined for its preventive effect against colonic tumorigenesis in a model system with male F-344 rats. The rats were intraperitoneally injected with azoxymethane (15 mg/kg BW) once a week for 3 wk and were fed a 20.6% HMF diet (+0.4% DL-Met) or 14.7% casein diet (+0.3% DL-Met) supplemented with 0.2% sodium deoxycholate (DCA) or without supplementation. Twelve wk later, 5 rats of each group were inspected for formation of tumors but no tumors were visible to the naked eye. The DCA-fed casein group was conspicuous for a low count of aberrant crypt foci. At 39 wk, 6 rats of the DCA-fed casein group (n = 10) and 3 rats of the DCA-fed HMF group (n = 9) had a total of 18 tumors with a major axis of 4.0 +/- 0.4 mm and 3 tumors with an axis of 2.0 +/- 0.1 mm, respectively, in contrast to only a single tumor for the DCA-unfed casein group (nil for the DCA-unfed HMF group). The difference in tumor number and size was considered significant between these DCA-fed casein and HMF groups; that is to say, HMF feeding retarded tumor development despite the frequent occurrence of pre-neoplastic lesions. In addition, fecal bile acid excretion was much more elevated by HMF feeding than by casein feeding. It can be assumed from these observations that the antitumorigenicity of HMF is due to the inhibitory effect of soybean resistant proteins on reabsorption as well as the mucosal contact of bile acids in the intestine.

Topics: Animals; Azoxymethane; Bile Acids and Salts; Carcinogens; Caseins; Cholesterol; Colonic Neoplasms; Deoxycholic Acid; Feces; Lipids; Male; Molecular Weight; Precancerous Conditions; Rats; Rats, Inbred F344; Soybean Proteins; Steroids

In order to obtain information on the preventive effects of various food proteins against colonic cancer, six groups of azoxymethane-initiated mature Fischer rats (n = 10) were fed respective diets different in protein sources such as bovine milk casein (casein), high-molecular-weight fraction from protolytic digest of soy protein isolate (soybean HMF), hen's yolk defatted protein (yolk protein), wheat gluten and codfish meat, which had been supplemented with sodium deoxycholate (hereinafter, DCA) as a cancer promoter except for an additional DCA-unfed casein group. All of the living rats at checkpoints during the feeding period were examined by the use of a bronchus fiberscope for colonic tumor incidence at 6 wk intervals between the 10th and 34th wk, from which both blood and feces samples were taken at times of endoscopy. Tumorigenesis in the colon was perceived by endoscopy at wk 22 in the group fed DCA casein only and at wk 28 in the other groups except the DCA-unfed casein group. At wk 34, both soybean HMF and yolk protein groups ranked inferior to the DCA-unfed group in tumor incidence. When plasma steroid or lipid concentration was plotted against tumor incidence at wk 28 or 34, positive correlations were found between plasma bile acid concentration and tumor incidence at both weeks. With the exception of the DCA-unfed casein group, plasma bile acid concentration was reversely correlated to fecal bile acid excretion. Taken altogether, these results suggest that bile acids at higher concentrations in the plasma may serve as risk factors of colon tumor incidence.

Topics: Animals; Anticarcinogenic Agents; Bile Acids and Salts; Cholesterol; Colonic Neoplasms; Deoxycholic Acid; Dietary Proteins; Disease Models, Animal; Endoscopes, Gastrointestinal; Feces; Incidence; Male; Rats; Rats, Inbred F344; Triglycerides

The effects of deoxycholic acid (DCA) with and without all-trans-retinoic acid (ATRA) on the incidence of colon tumors induced by azoxymethane, the incidence of K-ras point mutation in colon tumors and the labeling index of colon mucosa were investigated in male Wistar rats. Rats received 5 weekly injections of 7.4 mg/kg body weight of azoxymethane. From the start of the experiment, all rats in 3 groups also received chow pellets containing 0.3% DCA with and without s.c. injections of 0.75 or 1.5 mg/kg body weight of ATRA every other day until the end of week 45. Oral administration of DCA significantly increased the incidence of colon tumors in week 45. Concomitant use of DCA and ATRA at either dose significantly attenuated the enhancement by DCA of colon tumorigenesis. Administration of DCA significantly increased the incidence of K-ras point mutation in colon tumors and the labeling index in the colon mucosa. Combined administration of DCA and ATRA significantly reduced the labeling index of colon mucosa, which was increased by DCA, but did not affect the incidence of K-ras point mutation in colon tumors. These findings suggest that DCA enhances development of colon tumors and that this enhancement is attenuated by ATRA. A possible mechanism of this enhancement is induction of K-ras point mutation. However, decreased cell proliferation in the colon mucosa may be closely related to the attenuation of DCA-enhanced colon tumorigenesis, but not suppression of K-ras point mutation.

Topics: Administration, Oral; Animals; Anticarcinogenic Agents; Azoxymethane; Base Sequence; Carcinogens; Colon; Colonic Neoplasms; Deoxycholic Acid; Drug Synergism; Genes, ras; Intestinal Mucosa; Male; Mitotic Index; Point Mutation; Proto-Oncogene Proteins p21(ras); Rats; Rats, Wistar; Tretinoin

Topics: Clinical Trials as Topic; Colonic Neoplasms; Confounding Factors, Epidemiologic; Deoxycholic Acid; Dietary Fiber; Edible Grain; Humans; Nutrition Surveys; Phytotherapy; United Kingdom; United States

Hyperproliferation of the colorectal mucosa is regarded as an early step in colorectal carcinogenesis. Deoxycholic acid, a secondary bile acid, stimulates colorectal epithelial proliferation in animals and is considered a tumor promoter in human colorectal carcinogenesis. The aim of this study was to investigate the correlation between colorectal mucosal proliferation and the serum deoxycholic acid level.. From each of 19 patients (10 men and 9 women) with (n = 3) or without (n = 16) colorectal adenoma, 18 biopsy specimens were obtained by colonoscopy, 3 from each of the 6 colonic segments. A crude nuclei fraction was prepared, and DNA was stained by propidium iodide to determine the proliferative index (the percentage of cells in the S and G2/M phases of the cell cycle) by flow cytometry. Serum levels of deoxycholic acid were determined by gas-liquid chromatography.. The colonic proliferation rates (median of the values obtained in all segments, 14.1%; range, 10.0-18.7%) and the fasting serum deoxycholic acid levels (median, 0.86 micromol/L; range, 0.28-1.58 micromol/L) showed a significant correlation (r = 0.51, P = 0.03). Serum lithocholic, cholic, chenodeoxycholic, and ursodeoxycholic acid levels were not correlated with the proliferation rates.. Levels of deoxycholic acid in serum are correlated with the rates of the colorectal mucosa. These results are consistent with the concept that deoxycholic acid promotes colorectal carcinogenesis.

Topics: Adenoma; Adult; Bile Acids and Salts; Biomarkers; Carcinogens; Cell Division; Colon; Colonic Neoplasms; Colonoscopy; Deoxycholic Acid; Female; Humans; Intestinal Mucosa; Male; Mitotic Index

Bile acids are important in the etiology of colorectal cancer. Bile acids induce apoptosis in colonic goblet cells at concentrations comparable to those found in fecal water after high-fat meals. Preliminary evidence indicated that cells of the normal-appearing (nontumorous) portion of the colon epithelium of colon cancer patients are more resistant to bile salt-induced apoptosis than are cells from normal individuals. In the present study, 68 patients were examined, and biopsies were taken at 20 cm from the anal verge, cecum, and descending colon. The patients included 17 individuals with a history of colorectal cancer, 37 individuals with adenomas, and 14 individuals who were neoplasia free. The mean bile salt-induced apoptotic index among normal individuals was 57.6 +/- 3.47 (SE), which differed significantly (P < 0.05) from the mean value of 36.41 +/- 3.12 in individuals with a history of colon cancer. The correlation between independent observers was 0.89 (P < 0.001), indicating good interobserver reliability. Components of variance comparing interindividual versus intraindividual sources of variation suggested that site-to-site variability, both between regions of the colon and for adjacent biopsies, was larger than the interpatient variability for individuals with a history of neoplasia. Therefore, there was "patchiness" of the susceptibility of regions of the colon to bile acid-induced apoptosis in individuals with a history of neoplasia (a patchy field effect). There was no obvious correlation of low-apoptotic index regions with regions in which previous neoplasias had been found and removed. On the other hand, for normal, i.e., neoplasia-free, individuals, there was relatively less intraindividual variation compared to interindividual variation. Our assay shows an association between resistance to bile acid-induced apoptosis, measured at 20 cm from the anal verge, and colon cancer risk. Thus, this assay may prove useful as a biomarker of colon cancer risk.

Topics: Adenoma; Anal Canal; Apoptosis; Bile Acids and Salts; Biological Assay; Colon, Sigmoid; Colonic Neoplasms; Colonic Polyps; Colorectal Neoplasms; Deoxycholic Acid; Dietary Fats; Disease Susceptibility; Drug Resistance; Feces; Humans; Intestinal Mucosa; Observer Variation; Quality Control; Rectum; Risk

A high-molecular-weight fraction after removal of water-soluble peptides from proteinase-treated soybean protein isolate (referred to as HMF) was examined for its effect on preneoplastic lesions in the rat colon. For this purpose, male Fisher-344 rats 7 wk old were divided into 8 groups (n = 5), of which 6 groups received 3 injections of azoxymethane (AOM, 15 mg/kg of body weight) for 3 wk once a week, while all were fed HMF or casein diets supplemented with or without deoxycholic acid (DCA) over a period of 4 wk. Two groups of AOM-treated rats were allowed free access to HMF or casein diets without supplemental DCA, respectively, while the others were pair-fed so as to be well matched in their food intake. There were no significant differences in growth parameters among the pair-fed groups. Feeding HMF diets raised fecal lipid and acidic steroid excretions to a greater extent than feeding casein diets, secondary bile acids being conspicuous among acidic steroids in the excreta irrespective of the presence or absence of DCA supplementation. As a result of observation for colonic aberrant crypt foci (ACF), the intake of HMF proved to reverse the reduction of ACF appearance by DCA. This result implies that secondary bile acids are caught and brought out by HMF, or rather its derivative "resistant protein," so as not to keep contact with colonic mucosae.

Topics: Animals; Azoxymethane; Bile Acids and Salts; Blood Proteins; Carcinogens; Chromatography, Thin Layer; Colonic Neoplasms; Deoxycholic Acid; Feces; Lipids; Male; Precancerous Conditions; Rats; Rats, Inbred F344; Soybean Proteins

High levels of bile acids in the colon may correlate with an increased risk of colon cancer, but the underlying mechanisms are not known. Proteoglycan structures have been shown to change when human colon cells differentiate in vitro. The expression of [(35)S]sulphated molecules was used as a phenotypic marker to study the effects of bile acids on the human-colon-carcinoma cell line CaCo-2. [(35)S]sulphated compounds were isolated from the medium of cell fractions of cells metabolically labelled with [(35)S]sulphate in the absence and presence of cholic acid, deoxycholic acid, chenodeoxycholic acid and lithocholic acid (LA). Labelled molecules were analysed by gel chromatography, HPLC and SDS/PAGE in combination with chemical and enzymic methods. The expression of (35)S-labelled proteoglycans was not affected by any of the bile acids tested. However, the level of sulphated metabolites increased 7-18-fold in different experiments during a 22 h labelling period in the presence of an LA concentration of 10 microg/ml (26.6 nmol/ml) compared with controls. Further analyses showed that this was due, at least in part, to the sulphation of LA itself. This sulphation of LA was a rapid process followed by secretion back to the medium. Brefeldin A did not reduce the sulphation of LA, indicating that this conversion takes place in the cytosol, rather than in the Golgi apparatus of the CaCo-2 cells. LA in colon may be sulphated efficiently by the colonocytes to reduce the toxic effects of this particular bile acid. Sulphation may possibly be an important protective mechanism in the colon.

Topics: Bile Acids and Salts; Caco-2 Cells; Chenodeoxycholic Acid; Cholic Acid; Chromatography, High Pressure Liquid; Colonic Neoplasms; Deoxycholic Acid; Electrophoresis, Polyacrylamide Gel; Humans; Kinetics; Lithocholic Acid; Radioisotope Dilution Technique; Sulfates; Sulfur Radioisotopes

Ileal Na+-dependent bile acid transporter (ISBT) constituting a gateway to enterohepatic circulation of bile acids occurs exclusively at the distal site of the small intestine. In the present study, we examined colonic tumorigenesis promoted by deoxycholic acid in relation to the expression of the ISBT. For this purpose, the small intestine of a Fischer-344 rat was resected a length of 20 cm above the ileo-cecal valve (ileal resection) or below the duodenum (jejunal resection). Then, rats were treated with an intraperitoneal injection of azoxymethane (15 mg/kg body wt.) once a week for 3 weeks and fed a 20% casein diet supplemented with 0.2% deoxycholate for 39 weeks. Northern blot analysis demonstrated that the ISBT mRNA was hardly detectable in ileum-resected rats. The excretion of fecal bile acids was 1.5-fold higher in the ileum-resected group than in the jejunum-resected group (P < 0.05). On the contrary, the serum bile acids concentration of ileal-resected rats was about one-half of that of jejunum-resected animals (P < 0.05). The tumor incidence and the total tumor number were significantly higher in the ileum-resected group than in the jejunum-resected one (P < 0.05). Interestingly, no tumor was found at the proximal colon in the jejunum-resected group while tumors developed frequently at the proximal site as well as mid and distal colon in the ileum-resected group. These observations demonstrate that malabsorption of bile acids owing to the lack of ISBT enhanced colon tumorigenesis.

Topics: Animal Feed; Animals; Carrier Proteins; Colonic Neoplasms; Deoxycholic Acid; Enterohepatic Circulation; Ileum; Intestine, Small; Male; Organic Anion Transporters, Sodium-Dependent; Rats; Rats, Inbred F344; Symporters

Previous work from our laboratory indicated that the bile salt sodium deoxycholate (NaDOC) induced apoptosis in cultured cells and in normal goblet cells of the colonic mucosa. We also reported that the normal-appearing flat mucosa of patients with colon cancer exhibited apoptosis resistance. Using immunofluorescence in conjunction with confocal microscopy, we now report that high physiological concentrations (0.5 mM) of NaDOC result in the formation of nitrotyrosine residues, a footprint for the formation of reactive nitrogen species, including peroxynitrite, in plasma membrane-associated proteins of HT-29 cells. Because peroxynitrite is formed from the reaction between nitric oxide and superoxide anion, we specifically looked at the role of nitric oxide and superoxide anion in NaDOC-induced apoptosis. Pretreatment of cells with the inhibitor/antioxidants, N-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase, copper (II) 3,5-diisopropyl salicylate hydrate, a superoxide dismutase mimetic compound, and Trolox, a water-soluble analog of alpha-tocopherol, alone or in combination, sensitized cells to apoptosis induced by 0.5 mM NaDOC. These results suggest that nitric oxide may be part of a signaling pathway that is responsible for apoptosis resistance. The results also indicate that nitric oxide does not appear to protect cells against NaDOC-induced apoptosis by scavenging superoxide anion.

Topics: Apoptosis; Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Enzyme Inhibitors; Fluorescent Antibody Technique; Free Radical Scavengers; Humans; Microscopy, Confocal; NG-Nitroarginine Methyl Ester; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Salicylates; Superoxides; Tumor Cells, Cultured; Tyrosine

To elucidate the role of fecal steroids in the malignant tumor formation of colonic epithelial cells, we examined the effects of dietary deoxycholic acid (DCA) and cholesterol (CHL) on fecal steroid concentrations and their impact on colonic crypt cell proliferation. Twenty 5-week-old male Fischer 344 rats were provided with either a control semisynthetic diet or the same diet supplemented with 0.15% DCA and 1% CHL (steroid diet) over a 5-week period. The effects of these two diets were compared among rats that were either injected with azoxymethane (AOM), a known gastrointestinal carcinogen, or saline. In a 2 x 2 factorial design, rats fed each of these diets were given two weekly subcutaneous injections of either AOM (15 mg/kg b.w.) or saline at 6 and 7 weeks of age. At 9 weeks of age, fecal samples were obtained for analysis of bile acids, CHL and its bacterial metabolites of intestinal microflora. At 10 weeks of age, animals were sacrificed and colonic proliferation was assessed as vincristine-accumulated mitotic figures per crypt. Rats fed the steroid diet had significantly elevated fecal bile acid (5x, P < 0.001) and neutral steroid (10x, P < 0.01) levels when compared to those fed the control diet. AOM treatment did not appear to influence these levels. However, rats injected with AOM had a significant increase (P < 0.001) in their rate of colonic cell proliferation as compared to saline-injected control animals on both diets. Furthermore, rats fed the steroid diet had a significantly higher (P < 0.001) cell proliferation rate than animals fed the control diet. The effects of AOM treatment and the steroid diet on cell proliferation were additive. Our results demonstrate that high concentrations of neutral and acid steroids in the colonic lumen can enhance carcinogen-induced elevated cell proliferation and thus may play a key role in the etiology of colon cancer.

Topics: Animals; Azoxymethane; Bile Acids and Salts; Body Weight; Carcinogens; Cell Division; Cholesterol, Dietary; Cocarcinogenesis; Colon; Colonic Neoplasms; Deoxycholic Acid; Eating; Feces; Male; Precancerous Conditions; Rats; Rats, Inbred F344; Steroids

The objective of this study was to investigate the effect of deoxycholic (DCA) and lithocholic (LCA) acids on the postinitiation phases of colon cancer. Male Sprague-Dawley rats (n = 170) were injected with azoxymethane (2 injections at 15 mg/kg body wt sc given 1 wk apart) and fed a control (CON) AIN-93 diet. Two weeks after the second azoxymethane injection, 10 animals were killed and aberrant crypt foci (ACF) were enumerated. The remaining animals were randomly assigned to four diet groups: 1) CON, 2) DCA, 3) LCA, and 4) high fat (HF, a positive control group). Bile acid diets consisted of 0.2% by weight DCA or LCA; HF diets consisted of 20% fat (5% soybean oil + 15% beef tallow by weight). Animals were killed at Weeks 3, 12, and 20 (from 1st carcinogen injection), and number and growth features of ACF and adenomatous lesions were enumerated in the colon. At Week 12, ACF number and small, medium, and large (1-3, 4-6, and > or = 7 crypts/focus, respectively) ACF were higher in the HF group than in the DCA, LCA, and CON groups (p < or = 0.05). By Week 20, ACF number and small, medium, and large ACF were similar in the LCA and HF groups, whereas the response was similar in the DCA and CON groups. Average crypt multiplicity was higher in the HF and LCA groups than in the DCA and CON groups (p < or = 0.05). Microadenoma (MA) incidence was higher in the HF group than in the CON and LCA groups (p < or = 0.05). Regional distribution patterns for ACF number were similar to MA and tumor distribution patterns within the CON, DCA, and HF groups. In the LCA group, ACF number and MA showed a proximal predominance in regional distribution, whereas tumors showed a distal predominance. HF diets provided the most stimulatory environment, immediately enhancing the number and growth of ACF and MA incidence. In conclusion, HF and LCA diets exerted distinct effects on postinitiation phases of colon cancer, whereas the DCA diet did not.

Topics: Animals; Azoxymethane; Carcinogens; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Lithocholic Acid; Male; Random Allocation; Rats; Rats, Sprague-Dawley

It has been shown that in vitro incubation of human colonic biopsies with the secondary bile acid deoxycholic acid (DCA) leads to the hyperproliferation of colonic crypt cells with an expansion of the proliferative zone, which is regarded as a biomarker of increased cancer risk. Sodium selenite (SSE), on the other hand, has been implicated as a protective agent in experimental studies, but toxic effects were reported as well, depending on the dose of SSE. To elucidate the effects of SSE on human colonic mucosa, biopsies from endoscopically normal sigmoid colon tissue of 30 subjects were incubated with 5 microM DCA or a combination of 5 microM DCA and SSE in concentrations of 5, 10, 20, 50, 80, and 100 microM, respectively. Equimolar NaCl incubations served as a control. Proliferating cells were labeled by bromodeoxyuridine immunohistochemistry, and the labeling index (LI) was computed. In the experiments using 5, 10, and 20 microM SSE, the whole crypt LI was significantly lower after DCA + SSE incubation (0.136, 0.118, and 0.110, respectively) compared to that after incubation with DCA alone (0.172, 0.157, and 0.165, respectively; P < 0.01). The corresponding LIs during DCA + SSE incubation were comparable to the LIs obtained after NaCl incubation (average LI = 0.14). Contrary to this finding, severe cell damage was observed in the biopsies that were incubated with the higher SSE concentrations of 50 microM and above. The antiproliferative effects of SSE may indicate a possible protective effect in the prevention of human colon cancer development. However, the observed toxic effects of higher SSE concentrations strongly suggest the need for additional studies before general recommendations for the use of SSE in colon cancer prevention can be made.

Topics: Adult; Aged; Anticarcinogenic Agents; Cell Division; Cells, Cultured; Cholagogues and Choleretics; Colon, Sigmoid; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Female; Humans; Intestinal Mucosa; Male; Middle Aged; Sodium Selenite

Short chain fatty acids (propionate and butyrate) and deoxycholic acid (DCA) are able to induce apoptosis in HT-29 colonic tumor cell line, but DCA induces a much higher level of apoptosis than butyrate and propionate. Mixtures of DCA with butyrate or propionate enhance the effect of the single components. Apoptosis is not affected by the PKC, PTK or de novo mRNA and protein synthesis inhibitors, so that the involvement of these enzymes and processes is ruled out. In contrast, DCA-induced apoptosis is directly related to [Ca2+]i concentration as demonstrated by the apoptosis inhibition caused by [Ca2+]i chelator BAPTA/AM.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Apoptosis; Butyrates; Butyric Acid; Calcium; Chelating Agents; Colonic Neoplasms; Cycloheximide; Dactinomycin; Deoxycholic Acid; Dose-Response Relationship, Drug; Egtazic Acid; Enzyme Inhibitors; Genistein; Humans; Isoflavones; Propionates; Protein Synthesis Inhibitors; Time Factors; Tumor Cells, Cultured

Apoptosis of tumor cells is an important growth-regulating event in tumor masses. In this study we have confirmed that deoxycholic acid (DCA) and the short-chain fatty acids (SCFA) butyrate and propionate induce a time- and concentration-dependent apoptosis in two human colon tumor cell lines: HT-29 and CaCO2. DCA is more potent, inducing effects at low concentration (50 microM) and after 24 hours of incubation, whereas SCFA (4 mM) requires 72-96 hours of treatment. Combining low concentrations of DCA (12.5-25 microM) with butyrate and propionate (4 mM) produces an additive effect on the percentage of apoptotic cells, as demonstrated by flow cytometry and DNA fragmentation. Protein kinase C, protein tyrosine kinase, and gene transcription/translation inhibitors do not significantly modify the rate of apoptosis, whereas the intracellular Ca2+ chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) completely abolishes the DCA-induced effect without affecting the SCFA-induced apoptosis. Measurement of intracellular Ca2+ by inverted fluorescence microscopy reveals that DCA induces a rapid increase of cytosolic Ca2+ that is abolished when the cells are preincubated with BAPTA-AM, whereas ethyleneglycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid has a minimal effect. In contrast, SCFA does not modify the intracellular Ca2+ concentration. Thus the DCA-induced apoptosis is a Ca(2+)-dependent process, whereas the intracellular signals responsible for the SCFA-induced effect remain unknown. The ionophore activity of DCA could be responsible for the increased intracellular Ca2+, but other mechanisms, such as activation of phospholipase C and phosphoinositide hydrolysis, have to be considered.

Topics: Apoptosis; Butyrates; Butyric Acid; Calcium; Chelating Agents; Colonic Neoplasms; Deoxycholic Acid; DNA Fragmentation; Egtazic Acid; Fatty Acids; Flow Cytometry; Humans; Propionates; Protein Biosynthesis; Protein Kinase C; Protein-Tyrosine Kinases; Transcription, Genetic; Tumor Cells, Cultured

The high incidence of colorectal cancer in Western society is believed to be strongly related to diet. Mutation of the p53 gene is a late event in colorectal carcinogenesis, and thus, the majority of pre-malignant adenomas express wild-type p53. As loss of p53 protein function is an important step in colorectal carcinogenesis, we investigated whether naturally occurring lumenal factors can modulate the expression of p53 in non-tumorigenic human colonic adenoma cell lines. Levels of p53 protein and mRNA were measured in adherent cells which had been incubated with growth-inhibitory concentrations of sodium butyrate (a by-product of dietary fibre fermentation) or sodium deoxycholate (a bile acid) for up to 48 hr. We report that both butyrate and deoxycholate can down-regulate the expression of wild-type and mutant p53. In contrast, incubation for 48 hr with the endogenous inhibitory growth factor TGFbeta1 did not alter p53 protein expression. Thus, in addition to cellular mechanisms which regulate p53 function, such as post-translational stabilisation, nuclear exclusion, negative feedback inhibition of p53 mRNA translation or binding of p53 by cellular proteins, p53 protein levels also may be regulated by changes in the level of p53 gene transcription. Furthermore, we show that lumenal factors are able to affect directly the expression of p53 protein in colonic epithelial cells.

Topics: Adenoma; Butyrates; Butyric Acid; Cell Division; Cholagogues and Choleretics; Colonic Neoplasms; Deoxycholic Acid; Down-Regulation; Gene Expression Regulation, Neoplastic; Histamine Antagonists; Humans; RNA, Messenger; Transforming Growth Factor beta; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The secondary bile acid deoxycholic acid is believed to be a promoter of large bowel cancer, in part by inducing colonic epithelial proliferation. The effects of deoxycholic acid on [3H]thymidine incorporation by the human colon cancer cell line HT29 and two differentiated subclones were measured and compared. The subclone HT29-C1 has features of mature absorptive cells and HT29-N2 cells secrete mucus under cholinergic control. The three cell lines were treated with deoxycholic acid (DCA) at concentrations of 0, 5, 10, 50, 100, 150, and 300 microM for 3, 6, 9, 15, 24, and 48 hr. A significant increase in proliferation was noted in HT29 cells only at 6 hr with 5 and 10 microM deoxycholic acid. Neither the subclone HT29-C1, nor HT29-N2 cells exhibited significant change in [3H]thymidine incorporation with DCA at these concentrations or time points. Higher doses of deoxycholic acid above 50 microM and duration of exposure greater than 24 hr were cytotoxic to all three cell lines. The proliferative effects of DCA in HT29 cells were not paralleled by changes in protein kinase C activity or protein kinase C isoform expression. Quantitative and qualitative differences in PKC isoform expression were not noted in the three cell lines used in this study. The proliferative effects of DCA on HT29 cells appear to be independent of the PKC signal transduction pathway.

Topics: Blotting, Western; Cell Division; Colon; Colonic Neoplasms; Deoxycholic Acid; Humans; Isoenzymes; Protein Kinase C; Signal Transduction; Thymidine; Tritium; Tumor Cells, Cultured

A high-fat and low-fiber diet is regarded as a major risk factor for colon cancer by increasing luminal contents of secondary bile acids. Calcium, on the other hand, has been implicated as a possible preventive agent in colon tumor development. In in vitro studies with human colonic epithelium, incubation with the secondary bile acid deoxycholic acid (DCA) induced hyperproliferation of colonic crypt cells which is regarded as a sign of preneoplastic transformation. In the present study the effects of calcium chloride (CaCl2) on DCA-induced hyperproliferation were tested at different stages of DCA-induced cell injury. Colonic biopsies from 36 patients (no tumors, polyps or IBD) were incubated with CaCl2 (1 and 10 mM) and 5 microM DCA which was added to the incubation medium either together with (experiment A), after (experiment B), or before CaCl2 (experiment C). Coincubation of the biopsies with DCA and 10 mM CaCl2 at the same time (experiment A) resulted in a significant reduction of whole crypt labeling index by 12% (p < 0.05), whereas in the other incubation experiments no significant growth-inhibitory effects could be demonstrated for CaCl2. These findings may best be explained by the formation of calcium-bound bile acid salts which lost most of their toxicity for the colonic cells.

Topics: Adult; Aged; Aged, 80 and over; Biopsy; Calcium; Cell Division; Cells, Cultured; Colon; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Female; Humans; Immunohistochemistry; Male; Middle Aged; Precancerous Conditions; Risk Factors

We studied the effects of bile acids on inducibility of the transcription factor AP-1 in human colon carcinoma LoVo cells. Firstly, cells were treated with chenodeoxycholic acid and the nuclear extracts from those cells were processed by electrophoretic mobility shift assays to analyze nuclear AP-1 DNA-binding activity. We demonstrated that chenodeoxycholic acid induced AP-1 DNA-binding activity in a dose- and time-dependent fashion. Antibody supershift experiments clearly revealed that the majority of protein components in induced AP-1 DNA-binding activity were the products of oncogenes c-fos and c-jun. On the other hand, DNA-binding activity in the nuclear extracts for either NF kappa B, Sp1, or ATF/CREB was not affected by bile acids, suggesting that the effect of bile acids was rather specific for AP-1. Transient transfection experiments supported this notion: expression of the AP-1-luciferase reporter construct was induced by bile acids in a dose-dependent manner, and expression of either reporter construct for NF kappa B, Sp1, or ATF/CREB was not influenced by treatment of the cells with bile acids. We also demonstrated that those bile acids efficiently activated AP-1-dependent promoter in DLD-1 cells, which (as well as LoVo cells), are derived from colon adenocarcinoma, but not in COLO320DM cells which are from colon carcinoid tumor. Thus, we may indicate that bile acids exclusively induce nuclear AP-1 activity in colon adenocarcinoma cells.

Topics: Activating Transcription Factor 1; Adenocarcinoma; Base Sequence; Bile Acids and Salts; Chenodeoxycholic Acid; Cholagogues and Choleretics; Cholic Acid; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; DNA Primers; DNA-Binding Proteins; DNA, Neoplasm; Enzyme Activation; Gene Expression Regulation; Genetic Vectors; Humans; Lithocholic Acid; Molecular Sequence Data; NF-kappa B; Podophyllin; Podophyllotoxin; Protein Kinase C; Tetradecanoylphorbol Acetate; Transcription Factor AP-1; Transcription Factors; Tumor Cells, Cultured; Ursodeoxycholic Acid

The objective of the present study was to examine the effect of modifying the fatty acid composition of membranes on cell growth and phosphoinositide specific phospholipase C (PLC) activity in HT-29 colon cancer cells. Cells were seeded at a density of 12 x 10(3) cells/cm2 and supplemented with 30 microM of either 18:0, 18:2 (n6) or 18:3 (n3) complexed to bovine serum albumin (BSA) in DMEM medium. Cell growth was followed for 12 days. The 18:0 supplemented cells (control) reached maximum growth at day nine which was greater than either 18:2 (n6) or 18:3 (n3) supplemented cells. There was no difference between the latter two groups in their growth. To investigate the fatty acid incorporation of the supplemented fatty acid and how they may influence composition in the cell membrane, we examined the fatty acid composition of each phospholipid (PL) species. Both phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were significantly influenced by the type of fatty acid supplemented. Supplementation with 18:0 resulted in HT-29 cell membranes having more monounsaturated fatty acids than the cells grown in the other fatty acids. Polyunsaturated fatty acid (PUFA) supplementation (both 18:2 and 18:3) resulted in the enrichment of PUFA in the PL fractions. Cells supplemented with 18:3 (n3) had the highest unsaturation index in membrane PE as compared to the other phospholipid species. PLC activity of the membranes was measured using PIP2 as a substrate in the presence of 15 micrograms alamethicin and 42 microM free calcium. The contribution of G protein to the activity of the enzyme was assessed using GTP gamma(S). PLC activity of HT-29 cells was 16% higher in the presence of GTP gamma(S) response. GTP gamma(S)-activated PLC activity of 18:3 (n3) supplemented cells was 81% of those supplemented with either 18:0 or 18:2 (n6) cells. It is concluded that the decrease in cell proliferation with supplementation with 18:3 (n3) may be mediated through its inhibitory effect on PLC, which provides the second messengers for protein kinase C (PKC) activation. PLC may be influenced by an increased unsaturation index of the PE fraction of the HT-29 tumor cell membranes.

Topics: Alamethicin; Calcium; Carbachol; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Enzyme Activation; Fatty Acids; GTP-Binding Proteins; Guanosine Diphosphate; Guanosine Triphosphate; Humans; Membrane Lipids; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylinositols; Phosphatidylserines; Phospholipids; Sphingomyelins; Tumor Cells, Cultured; Type C Phospholipases

Polyamines are low molecular weight aliphatic amines required for normal cellular growth which are ubiquitously found in all living tissues. Polyamine biosynthesis is known to increase with mitogenesis, and elevated polyamine concentrations are found in hyperproliferative tissues. Quantitation of tissue polyamine content may thus provide a biochemical measure of proliferation, with potential biomarker application to the colonic mucosa where dysregulated epithelial proliferation is associated with cancer risk. This study was performed to validate polyamine analyses as a measure of cellular proliferation, and to preliminarily assess polyamine characteristics when applied to clinical samples. Using FHC, a human colonic epithelial cell line, for in vitro experimentation, deoxycholic acid or retinol was added to freshly passaged cultures to either stimulate or inhibit proliferation, respectively. Parallel cultures were then assayed for (1) proliferation by sulforhodamine B staining; and (2) polyamine content by a high-performance liquid chromatographic method. Deoxycholic acid stimulated, and retinol inhibited proliferation in dose-dependent fashion. Polyamine content, specifically the spermidine content and the spermidine/spermine ratio, also increased or decreased in response to culture with deoxycholic acid or retinol, respectively. Significant linear correlations between proliferation and spermidine (r = 0.858, P < 0.001), and with the spermidine/spermine ratio (r = 0.574, P < 0.05) were observed. When quantitative polyamine analyses were applied to human colonic specimens, replicate mucosal sampling revealed a high degree of intra-individual variability, indicating a heterogeneous distribution of polyamines within anatomically confined colonic segments. The results support a role for quantitative polyamine analyses as a correlative measure of colonic epithelial proliferation; however, intraindividual variability may limit the utility of colorectal biomarker measurements.

Topics: Biomarkers; Cell Division; Cell Line; Cells, Cultured; Chromatography, High Pressure Liquid; Colon; Colonic Neoplasms; Deoxycholic Acid; Epithelium; Humans; Intestinal Mucosa; Kinetics; Pneumatosis Cystoides Intestinalis; Polyamines; Rectum; Spermidine; Spermine; Vitamin A

A high-fat/high-protein diet has been reported to promote colon cancer by increasing luminal bile acid and ammonia concentrations, whereas butyrate, calcium, and low colonic pH may have protective effects. In this study, bromodeoxyuridine labeling of colonic epithelium was investigated after incubating biopsies from the ascending colon of 70 patients with HCl (20 mM, pH 6.0), butyric acid (H-BUT, 20 mM, pH 6.0), sodium butyrate (Na-BUT, 10 mM, pH 8.0), CaCl2 (10 mM), calcium butyrate (Ca-BUT, 10 mM), ammonium butyrate (NH4-BUT, 10 mM), deoxycholic acid (DCA, 5 microM), and a combination of DCA and Na-BUT (DCA/Na-BUT, 5 microM/10 mM). Compared to NaCl, H-BUT and Na-BUT increased the whole crypt-labeling index significantly, whereas HCl and CaCl2 had no effect. Reduced labeling, however, occurred with Ca-BUT in comparison to equimolar Na-BUT. No differences in the labeling indexes were found for NH4-BUT compared to Na-BUT, but increased labeling with expansion of the proliferative zone to the upper 40% of the crypt was seen with DCA compared to NaCl. DCA-induced hyperproliferation was abolished by coincubation with DCA/Na-BUT. These data suggest that butyrate, calcium, and DCA have complex influences on mucosal proliferation. Since luminal concentrations of these compounds are influenced by dietary interventions, the findings of this study may be of particular interest with regard to colon cancer development and prevention.

Topics: Adult; Aged; Aged, 80 and over; Ammonia; Butyrates; Butyric Acid; Calcium; Calcium Chloride; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Female; Humans; Hydrochloric Acid; Hydrogen-Ion Concentration; Intestinal Mucosa; Male; Middle Aged

Quantitative aspects of bile acid cytotoxicity to colon cancer cell lines were investigated because of the etiological role in colon carcinogenesis attributed to the toxic effects of bile acids on colon mucosal cells. The cytotoxicity of major colonic bile acids differed. Lithocholate was the most toxic, followed by chenodeoxycholate and deoxycholate, with cholate being non-toxic over the concentration range studied. Cytotoxicity increased with time of exposure. Values for IC50 for some of the acids were determined to be in the physiological range, as estimated from their concentrations in fecal water. The results suggest dietary factors that contribute to bile acid mucosal damage. They also identify factors of possible importance in the association of high concentrations of bile acids in fecal water with risk for colon cancer.

Topics: Bile Acids and Salts; Cell Survival; Chenodeoxycholic Acid; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Feces; Humans; Least-Squares Analysis; Lithocholic Acid; Serum Albumin, Bovine; Time Factors; Tumor Cells, Cultured

A factor in colon carcinogenesis might be the partial defeat in colon epithelial cells of the protective enzymic barrier against xenobiotics, via bile acid inhibition of enzymes that detoxify mutagens. The applicability of aspects of this concept to glucuronosyltransferase, a phenol detoxification enzyme, was tested in a colon cancer cell line. Inhibition of glucuronidation of the test substrate, 4-methylumbelliferone, occurred at bile acid concentrations found in faecal water, and depended on pH for some bile acids. Lithocholate was the most inhibitory: the concentration causing 50% inhibition of the initial rate of glucuronidation (IC50) was about 3 microM at pH 7.4 and at pH 6.2. The inhibitory potency of deoxycholate and chenodeoxycholate increased when pH decreased, but still remained less than that of lithocholate: the IC50 for deoxycholate was 88.5 microM at pH 7.4, and 14.8 microM at pH 6.2, and for chenodeoxycholate the IC50 was 67.4 microM at pH 7.4, and 21.7 microM at pH 6.2. Cholate did not cause appreciable inhibition. The inhibitory effects were additive when lithocholate was present together with either deoxycholate or chenodeoxycholate. The results provide a mechanism for the comutagenicity of bile acids, a feature of which is the inter-relation of bile acid comutagenicity specifically with mutagens that are inactivated by a bile acid-inhibitable enzyme. The results are also in accord with the view that high concentrations of bile acids in solution in faecal water, especially lithocholate, are a risk factor for colon cancer.

Topics: Bile Acids and Salts; Chenodeoxycholic Acid; Colon; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Fluoresceins; Fluorescence; Fluorescent Dyes; Glucuronates; Glucuronic Acid; Glucuronosyltransferase; Glutathione Transferase; Humans; Hymecromone; Lithocholic Acid; Permeability; Tumor Cells, Cultured; Xenobiotics

Peroral sulpholithocholic acid (SLC) promoted colonic tumorigenesis in conventional rats. We then tested this compound in the mouse, a species with different bile acid metabolism from the rat. Female conventional ICR mice received 0.5 mg of N-methyl-N-nitrosourea (MNU) three times in one week intrarectally or 16 mg/kg body weight of 1,2-dimethylhydrazine (DMH) subcutaneously once a week for 10 weeks, followed by a basal diet (CE-2), or CE-2 containing SLC or lithocholic acid (LC) (both at 0.5 mmol/100 g CE-2) for 40 weeks. At autopsy, numbers of mice bearing colonic neoplasms were 4/26 (15%) in the MNU + CE-2, 4/23 (17%) in the MNU + SLC, 5/28 (18%) in the MNU + LC, 12/24 (50%) in the DMH + CE-2, 6/23 (26%) in the DMH + SLC and 11/27 (41%) in the DMH + LC group. The DMH + SLC group had less adenocarcinomas than did the DMH + CE-2 and the DMH + LC group (P < 0.05). Total faecal bile acids in the mice fed on bile salts showed threefold increases compared with those on the basal diet. Sulphates constituted an average 7% and 19% of faecal bile acids in the MNU + SLC and DMH + SLC group, respectively. These results indicated that effects of peroral SLC on colonic carcinogenesis correlated with the degree of desulphation of SLC in the intestine and sulphates per se inhibited colonic carcinogenesis.

Topics: 1,2-Dimethylhydrazine; Adenocarcinoma; Adenoma; Administration, Oral; Administration, Rectal; Animals; Bile Acids and Salts; Carcinogens; Carcinoma, Squamous Cell; Cholic Acids; Colon; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Feces; Female; Germ-Free Life; Injections, Subcutaneous; Lithocholic Acid; Methylnitrosourea; Mice; Mice, Inbred ICR

Human colon adenocarcinoma cells, treated with deoxycholate for 24 h prior to exposure to 1 mM butyrate, exhibited dose-dependent increases in the activities of three markers of colonic differentiation (alkaline phosphatase, lactase and CEA). Treatment with deoxycholate alone, for 24 h or longer, did not increase the secretion of CEA or the activities of either of the brush border-associated enzyme activities. Increases in differentiation markers were found to be bile acid-specific. Pretreatment with either dehydrocholic acid or cholic acid, even at cytotoxic concentrations, led to no significant butyrate-induced increases in brush-border associated hydrolase activities. The addition of a bacterial superoxide dismutase decreased the short-term cytotoxicity of deoxycholate and increased the maturation-potentiating effects of the bile acid in HCT-116 DO cells. The results of these studies demonstrate that bile acids, which are commonly thought to have tumor promoting activities in vivo, may also have physiological effects which serve to limit carcinogenic processes in the human colon by potentiating tumor cell differentiation.

Topics: Adenocarcinoma; Alkaline Phosphatase; beta-Galactosidase; Butyrates; Butyric Acid; Cell Differentiation; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Induction; Humans; Lactase; Superoxide Dismutase

The aim of this study was to determine whether changes in serum free radicals may be useful for the early detection of precancerous conditions in the rat colon after treatment with a direct carcinogen (N-Methyl-N'-Nitro-N-Nitrosoguanidine, MNNG) and a secondary bile acid (deoxycholic acid, DCA) as a tumor promoter. It was shown that a significant increase in the concentrations of free radicals in sera of rats following their treatment with MNNG and DCA was observed as early as the 18th week after the beginning of the treatment. Since our results have shown that these alterations occurred in parallel with neoplastic transformations in the rat colon, it suggests that the increase in serum free radicals reflected the precancerous situation in the animals and may be useful in the early detection of cancer development. The possible role of free radicals in deoxycholate-induced liver toxicity was discussed.

Topics: Animals; Colonic Neoplasms; Deoxycholic Acid; Free Radicals; Gentisates; Hydroxybenzoates; Male; Methylnitronitrosoguanidine; Precancerous Conditions; Rats; Rats, Sprague-Dawley

Protein kinase C (PKC) is the target for a number of tumor promoters. The mechanism underlying the promoting effects of bile acids in colorectal cancer is not understood. We report that sodium deoxycholate (DOC) triggered activation of PKC in physiological conditions. The biphasic effects of DOC upon PKC activation were Ca(2+)-stimulated and did not require phosphatidylserine (PtdSer) as phospholipid co-factor. The optimal rate of activation was obtained at 0.4 mM DOC and reached approximately half the maximal rate of activation obtained in the presence of PtdSer. Similarly to PtdSer, DOC supported diacylglycerol- as well as phorbol-ester-mediated PKC activation. The reciprocal effects of PtdSer and DOC upon PKC in either 0.5 mM CaCl2 or 0.5 mM EGTA suggest that DOC interacts with the phospholipid-binding domain to elicit PKC activation. DOC-supported enzyme activation exhibited substrate specificity different from that of PtdSer-supported enzyme activation. All tested primary and secondary bile acids activated PKC to various extents, with DOC being the most potent. We suggest that amphipathic bile acids acting in a PtdSer-like manner provide the hydrophobic environment required for PKC activation. Treatment of 32P-labeled platelets and colonic cells HT29 Cl.19A with DOC enhanced the phosphorylation of endogenous substrates for PKC. Colonic cells responsive at 50 microM DOC, appeared to be 10-fold more sensitive than platelets. We suggest that direct or indirect activation of PKC by bile acids may account for the promoting effects of these non-phorbol-ester-type tumor promoters.

Topics: Bile Acids and Salts; Blood Platelets; Calcium; Carcinogens; Colonic Neoplasms; Deoxycholic Acid; Enzyme Activation; Humans; Phosphorylation; Protein Kinase C; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

The antitumorigenic effect of cryptoporic acid E (CPA-E), a dimeric drimane sesquiterpenoid isolated from the fungus Cryptoporus volvatus, on colon carcinogenesis was investigated. Female F344 rats given an intrarectal instillation of 2 mg of N-methyl-N-nitrosourea 3 times weekly in weeks 1 and 2 were fed diet containing 0.2% CPA-E from week 3. Female ICR mice given 15 weekly intraperitoneal injections of 10 mg of 1,2-dimethylhydrazine/kg body weight during weeks 1 to 15 were fed diet containing 0.06% CPA-E from week 1. The experiment was terminated at week 35 for rats and at week 25 for mice. The incidence and the number of tumors per animal were reduced in CPA-E-fed animals compared to the controls: 31% vs. 75% (P less than 0.05) and 0.4 +/- 0.2 (SEM) vs. 0.9 +/- 0.2 (0.1 greater than P greater than 0.05) in rats, and 31% vs. 63% (0.1 greater than P greater than 0.05) and 0.4 +/- 0.2 vs. 2.4 +/- 0.8 (P less than 0.05) in mice (16 animals in each group). Intrarectal deoxycholic acid-induced colonic mucosal ornithine decarboxylase activity was significantly lowered in CPA-E-fed animals compared to controls. This shows an antipromoting activity of CPA-E against colon carcinogenesis. Thus, it was concluded that CPA-E inhibits colon cancer development in both rats and mice treated with 2 different colon carcinogens.

Topics: 1,2-Dimethylhydrazine; Animals; Anticarcinogenic Agents; Biomarkers, Tumor; Carcinogens; Colon; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Enzyme Induction; Feeding Behavior; Female; Intestinal Mucosa; Methylnitrosourea; Mice; Mice, Inbred ICR; Ornithine Decarboxylase; Polyporaceae; Rats; Rats, Inbred F344; Sesquiterpenes; Weight Gain

Methods of morphological, histochemical and immunohistochemical analyses were used to further characterize differences between tumourous and adjacent grossly normal tissues in chemically-induced colon cancer in rats. Colon tumors were induced by the treatment of rats with 1,2-dimethylhydrazine or with N-methyl-N'-nitro-N-nitrosoguanidine alone or with subsequent treatment with deoxycholic bile acid. Tissues were studied morphologically (for the presence of goblet cells in the colon crypts, and the extent of infiltration of lymphocytes into the crypts and between them), histochemically (for the presence of positive reaction to neutral and acid mucopolysaccharides) and immunohistochemically (for the presence of tissue polypeptide antigen). All data were evaluated quantitatively, and index of tissue damage was calculated for both tumorous and non-tumorous tissues. Significant morphological differences were found between tumorous and adjacent apparently normal tissue. Histochemically and immunohistochemically, both types of tissue reacted very similarly to exposure to the carcinogens. Index of damage was significantly different from normal untreated colon in both kinds of tissue. It was suggested that precancerous state in tissue adjacent-to-tumor could be detected using the combination of these methods.

Topics: 1,2-Dimethylhydrazine; Animals; Carcinogens; Colon; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Glycosaminoglycans; Histocytochemistry; Immunohistochemistry; Male; Methylnitronitrosoguanidine; Rats; Rats, Sprague-Dawley; Time Factors

The development of tumorigenic conditions in the carcinogen-exposed rat colon was studied using selected morphological, histochemical, immunohistochemical and biochemical methods of analysis. Rats were treated with two carcinogens: 1,2-dimethylhydrazine and N-methyl-N'-nitro-N-nitrosoguanidine alone or with deoxycholic acid as a tumor promoter. It was found that 3 months after treatment of animals with the carcinogens the following changes were developed in colonic tissue: infiltration of lymphocytes in the mucous membrane, high increase in mitotic index among epithelial cells, negative reactions of colonic cells for neutral mucopolysaccharides and sulfomucins and positive reactions to carboxyl groups, nonsulfated acid mucosubstances and tissue polypeptide antigens. An increase in the activity of ornithine decarboxylase in colonic tissue was developed within the same time period and has been seen only in those tissues which were characterized by the development of precancerous conditions. Individual variations were observed in the manifestation of the studied parameters in rat neoplastic colonic tissues. It is suggested that these differences reflect an individual sensitivity of animals to carcinogens and the magnitude of the dysplastic processes induced in the colon.

Topics: 1,2-Dimethylhydrazine; Animals; Biomarkers, Tumor; Carcinogens; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Histocytochemistry; Immunohistochemistry; Male; Methylnitronitrosoguanidine; Mitotic Index; Ornithine Decarboxylase; Peptides; Precancerous Conditions; Rats; Rats, Sprague-Dawley; Tissue Polypeptide Antigen

Calcium contributes to the progression of epithelial cells through all phases of the proliferative cycle and into stages of cell differentiation; intracellular concentrations of calcium that are required for cell renewal, however, are lower than those required for epithelial-cell differentiation. These effects of calcium are modulated by interactions with 1,25-dihydroxy-vitamin D3, phosphate, and fatty acids, all of which are partly dependent on dietary intake. In rodent models, increased dietary calcium inhibited hyperproliferation of colon epithelial cells induced by increased levels of fatty acids or bile acids present in the colon. When carcinogens induced hyperproliferation of colon epithelial cells the hyperproliferation was decreased by added dietary calcium, and in several animal models the occurrence of carcinogen-induced carcinomas of the colon decreased with increased dietary calcium. A nutritional stress diet, designed to represent human Western dietary intake of calcium, phosphate, vitamin D, and fat, produced hyperproliferation and hyperplasia in the colons of rodents; these effects were reduced by increasing dietary levels of calcium. Decreased levels of ornithine decarboxylase also were reported in human and rodent colon mucosa exposed to increasing levels of calcium. In human subjects at increased risk for familial colon cancer, hyperproliferation of colon epithelial cells was reduced after oral dietary supplementation with calcium. In epidemiological studies, several investigators reported inverse correlations between levels of dietary calcium intake and the incidence of colon cancer. Extrapolation of the data have suggested a protective effect of total calcium intakes above 1500 to 1800 mg/day.

Topics: 1,2-Dimethylhydrazine; Animals; Calcium; Calcium, Dietary; Carcinogens; Cell Division; Colon; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Humans; Mice; Rats; Vitamin D

Transmission electron microscopy (TEM) was used to study ultrastructural changes that accompanied the tumorous transformation of the descending rat colon epithelial cells, following short treatment with a direct carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), with subsequent prolonged treatment with secondary bile acids, lithocholic (LCA) and deoxycholic (DCA), which enhanced tumor formation. Colon epithelial cells after long treatment with bile acids alone were characterized by the presence of an irregular nuclear membrane, ring-shaped rough endoplasmic reticulum (RER), collagen-like tonofilaments and membrane-bound mucous vacuoles. Tumor cells which developed following treatment with MNNG alone were characterized by the irregular shape of the nuclear membrane and, sometimes, by polynuclei, accumulation of large amounts of mitochondria, loss of cell-cell contacts and by endocytosis of the cell membrane. After combined treatment with MNNG and LCA, many mitochondria lost their membranous envelope; in the cytoplasm many collagen-like tonofilaments, ring-shaped RER and many free ribosomes were present. After treatment with MNNG and DCA, many polysomes were found in the cytoplasm. It was apparent that treatment with MNNG alone caused the development of adenocarcinoma-like tumors, while additional treatment with secondary bile acids significantly enhanced these changes, which were accompanied by the development of atypia and anaplasia of epithelial cells, with many irregularities in intracellular organization.

Topics: Animals; Bile Acids and Salts; Colon; Colonic Neoplasms; Deoxycholic Acid; Epithelium; Lithocholic Acid; Male; Methylnitronitrosoguanidine; Rats; Rats, Inbred Strains; Rectum

Topics: Adenoma; Adult; Aged; Aged, 80 and over; Bile Acids and Salts; Cell Cycle; Cell Division; Chenodeoxycholic Acid; Cholesterol; Cholic Acid; Cholic Acids; Colon; Colonic Neoplasms; Colonic Polyps; Deoxycholic Acid; Feces; Female; Humans; Lithocholic Acid; Male; Middle Aged; Phytosterols; Rectum; Sterols

Topics: Bile Acids and Salts; Cohort Studies; Colonic Neoplasms; Deoxycholic Acid; Duodenal Ulcer; Feces; Female; Gastrectomy; Humans; Lithocholic Acid; Male; Risk Factors; Sex Factors; Stomach Ulcer; Vagotomy, Truncal

Soluble fecal acidic lipid concentrations and colonic epithelial cell proliferation rates, two biologic markers for colon cancer, were compared in a group of colon cancer patients and a group of healthy controls. No significant difference was found in the concentration of bile acids (155 (136) microM, n = 33, versus 103 (89) microM, n = 19) in the aqueous phase of feces from patients and controls or in proliferation rates between the two groups, the volume density of tritiated thymidine-labeled epithelial cells being 0.153 (0.050), n = 8, for the patients and 0.164 (0.072), n = 11, for the controls. When the dietary intake of three food components known to influence both of the above factors (that is, fat, fiber, and calcium) was ascertained for the year preceding the study, the only significant difference observed was the higher calcium intake in the female patients than in the controls. The authors conclude that it may be premature to rely too heavily on either of the above markers to predict risk for developing this disease.

Topics: Adult; Aged; Aged, 80 and over; Bile Acids and Salts; Biomarkers, Tumor; Cell Division; Chromatography, Gas; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet; Fatty Acids; Feces; Female; Humans; Intestinal Mucosa; Male; Middle Aged

Colon cancer is the second most common type of cancer in the United States. Bile acids have been implicated in the etiology of this disease. In a previous study, we showed that bile acids can damage DNA in vitro. In this study, we report that this damage is largely prevented when the bile acids are pretreated with cellulose fiber. Preliminary data show that cellulose may act as a catalyst to promote polyesterification of bile acid to a biologically inactive form.

Topics: Cellulose; Chenodeoxycholic Acid; Coliphages; Colonic Neoplasms; Deoxycholic Acid; Dietary Fiber; DNA Damage; Transfection

Topics: Animals; Bile Acids and Salts; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet; Dietary Fiber; Feces; Humans; Intestinal Mucosa; Rats; Water

The mechanism of the anti-promoting effect of the prostaglandin (PG) synthesis inhibitor indomethacin in colon carcinogenesis was investigated. Male Sprague-Dawley rats received 0.002% water solution of indomethacin as drinking water freely for 3 days, then a subcutaneous injection of various doses of PGE2 and/or an intrarectal instillation of 12 mumol of sodium deoxycholate as a colon tumor promoter. Ornithine decarboxylase (ODC), a marker of tumor promotion, in the distal colonic mucosa was assayed at 4 hr after deoxycholate instillation. Indomethacin significantly suppressed the deoxycholate-augmented increase of ODC activity, while exogenous PGE2 restored or further increased the augmented ODC activity. The amount of PGE2 and the level of ODC activity were well correlated. However, PGE2 alone without deoxycholate did not increase the activity. Deoxycholate markedly increased colonic mucosal PGE2 at 1 hr after the instillation, and indomethacin decreased it. The results indicate that PGE2, the production of which is stimulated in the colonic mucosa by deoxycholate, is involved in the induction of colonic mucosal ODC. This is probably why PG synthesis inhibitors may inhibit the tumor promotion and prevent cancer development in the colon.

Topics: Administration, Oral; Administration, Rectal; Animals; Carcinogens; Colonic Neoplasms; Cyclooxygenase Inhibitors; Deoxycholic Acid; Dinoprostone; Indomethacin; Injections, Subcutaneous; Male; Prostaglandins E; Rats

The fecal steroid profiles of healthy subjects were compared with those of colorectal cancer (CRC) patients. The multicomponent profiles did not differ qualitatively in that CRC patients, like control subjects, had similar fecal steroids. The major bile acids detected in fecal extracts were lithocholic acid (LCA) and deoxycholic acid (DCA). The major sterol of animal origin was cholesterol and its bacterial metabolite coprostanol, whereas the major plant sterols were beta-sitosterol, stigmasterol, campesterol, and their corresponding bacterial metabolites. CRC patients excreted higher amounts of total major bile acids (LCA and DCA) than did the control group, but this difference was not significant. However, the LCA-to-DCA ratio was much higher in the CRC group [(1.43, p less than 0.01) compared with the control group (0.72)]. The control group excreted significantly higher amounts of total neutral sterols (p less than 0.001), sterols of animal origin (p less than 0.001), and plant sterols (p less than 0.001) compared with the CRC group; the plant sterols represented a much lower proportion of excreted total neutral sterols in the CRC group (p greater than 0.001) compared with the control group. We propose the following hypotheses. The LCA-to-DCA ratio may be an important discriminant market for CRC susceptibility. The fecal LCA-to-DCA ratio may depend on the differential hepatic synthesis of their respective precursors chenodeoxycholic acid (CDCA) and cholic acid. Hepatic synthesis of CDCA may be increased by more efficient conservation of dietary cholesterol because it has been shown that cholesterol of exogenous origin is the main precursor of this bile acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Diet; Feces; Female; Humans; Lithocholic Acid; Male; Middle Aged; Rectal Neoplasms; Sterols

This study investigated whether colonic absorption of secondary bile acids, especially deoxycholate in patients with adenomas could be decreased by oral lactulose. Bile acid metabolism was studied using bile sampling and 14C-deoxycholate kinetics in patients with colonic adenomatous polyps before and after four and 12 weeks of lactulose, 60 g/day. The results indicate that lactulose decreased the deoxycholate pool size from a mean of 22.0 (SD: +/- 13.8) to 14.3 (+/- 7.6) mumol/kg (p less than 0.025). Deoxycholate absorption fell from 3.8 (+/- 2.3) to 2.9 (+/- 1.4 mumol/kg/d (ns). The biliary bile acid composition decreased significantly in deoxycholate after four and 12 weeks with a rise in primary bile acids. There was a highly significant correlation between the %-change in DCA input and the %-change in DCA pool size (r = 0.89). Intestinal transit measured by the pellet method (4.1 +/- 1.9 to 2.4 +/- 0.6 day; p less than 0.01) and faecal pH decreased, while stool frequency and weight rose significantly. Significant correlations between the %-change in gut transit time and the %-change in DCA pool size or %-change in DCA input were absent. The results show that it is possible to lower colonic secondary bile acid absorption by long term lactulose feeding. This effect can be mediated by accelerated transit and the acidification of the colonic contents.

Topics: Administration, Oral; Adult; Aged; Bile; Bile Acids and Salts; Colon; Colonic Neoplasms; Colonic Polyps; Deoxycholic Acid; Disaccharides; Feces; Female; Humans; Intestinal Absorption; Lactulose; Middle Aged

To further understand the molecular mechanisms of bile acid-mediated colon tumor promotion, we have examined the possible role of protein kinase C (PKC) in this process. Protein kinase C has been implicated in tumor promotion because it is the receptor for the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA) and mediates the action of this compound as well as that of other tumor promoters and growth factors. Our studies show that, in a manner analogous to 12-0-tetradecanoyl-phorbol-13-acetate, deoxycholic acid (DOA) can induce a time-dependent cellular redistribution of PKC as well as a concentration-dependent overexpression of the ornithine decarboxylase gene. These results taken together with our previous findings demonstrating decreased levels of PKC in human colon carcinomas compared with adjacent normal mucosa provide evidence that PKC has a role in colon carcinogenesis.

Topics: Animals; Carcinogens; Cell Membrane; Colonic Neoplasms; Cytosol; Deoxycholic Acid; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Induction; Genes; Mice; Mice, Inbred C3H; Ornithine Decarboxylase; Protein Kinase C; RNA, Neoplasm; Time Factors; Tumor Cells, Cultured

Intrarectal exposure of the colon epithelium of the C57BL/6J female mouse to deoxycholic acid [(DCA) CAS: 83-44-3] markedly increased its sensitivity to orally administered 1,2-dimethylhydrazine [(DMH) CAS: 540-73-8]. While 4 mg DMH/kg body weight by itself increased the level of nuclear damage from a background level of 0.2-0.45 aberration per crypt, DMH when combined with DCA at a dose of 150 mg/kg increased the aberrations from 0.2 to 1.75 per crypt. This effect was observed over a wide range of DCA doses (20-300 mg/kg) and was evident when DMH was given up to 10 hours after the DCA. Similar results were observed with DCA in conjunction with benzo[a]pyrene (CAS: 50-32-8) and 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (CAS: 77094-11-2), though in these cases the time at which the peak of nuclear aberrations occurred was somewhat later. No enhancement was seen with DCA and gamma-radiation. These results show that DCA can enhance the nucleotoxic effects of several carcinogens and suggest that DCA can act as a cocarcinogen. The enhancement may be due to the effect of the bile acid on proliferation of the colon epithelial cells or to its effect on the permeability of mucosal cells.

Topics: 1,2-Dimethylhydrazine; Animals; Carcinogens; Cell Nucleus; Cocarcinogenesis; Colon; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Dose-Response Relationship, Drug; Female; Mice; Mice, Inbred C57BL; Mitotic Index; Time Factors

We have developed an isotope dilution method for determination of deoxycholic acid pool size and input rate which employs oral administration of 50 mg of [24-13C]deoxycholic acid and serum sampling. The method has been validated by classical isotope dilution technique using [24-14C]deoxycholic acid and bile sampling in five patients with colonic adenomas. Excellent agreement between pool sizes and input rates determined with 13C/12C isotope ratio measurements in serum and 14C measurements in bile was obtained when isotope ratios were measured in the conjugated fraction of deoxycholic acid in serum. We conclude that pool size and input rate of deoxycholic acid can accurately be determined by blood sampling after oral administration of [24-13C]deoxycholic acid, therewith eliminating the use of radioactive tracers and the need for bile sampling.

Topics: Adenoma; Adult; Aged; Carbon Isotopes; Carbon Radioisotopes; Colonic Neoplasms; Deoxycholic Acid; Humans; Isotope Labeling; Kinetics; Middle Aged

Cogent epidemiological and experimental data implicate bile acids as endogenous co-carcinogens in colorectal cancer. A series of experiments was designed to test the ability of sodium deoxycholate (SDC) to promote intestinal hyperplasia and neoplasia in rats (n = 265). The intermediary role of faecal anaerobes was explored in animals receiving oral metronidazole. Intrarectal instillation of SDC trebled tumour yield in functioning large bowel and increased both crypt depth and crypt cell production rate. Metronidazole reduced this tumour promotion without affecting SDC-induced hyperplasia. By contrast, SDC was totally inactive in colon isolated as a Thiry-Vella fistula. Bile acids probably promote colorectal carcinogenesis by stimulating mucosal hyperplasia but only in the presence of faeces.

Topics: Animals; Colonic Neoplasms; Deoxycholic Acid; Feces; Male; Metronidazole; Rats; Rats, Inbred Strains; Rectal Neoplasms

During a state of pure vitamin A deficiency, without any clinical manifestations, in colonic mucosa: ornithine decarboxylase activity is already stimulated, in deficient animals, by instillation of NaCl 9%. Sodium deoxycholate further enhances and markedly protracts the enzyme activity, as compared to normal rats. These results lead to the conclusion that vitamin A deficiency is a state of special sensibility to the promoter action. Retinol is hence physiologically necessary for natural resistance of intestinal cells against chemically induced tumor promotion.

Topics: Animals; Cell Division; Colon; Colonic Neoplasms; Deoxycholic Acid; Enzyme Activation; Intestinal Mucosa; Male; Ornithine Decarboxylase; Rats; Rats, Inbred Strains; Vitamin A Deficiency

Topics: Animals; Bile Acids and Salts; Calcium; Cholic Acid; Cholic Acids; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet; Dietary Fats; Feces; Humans; Mice; Rats; Risk

Intrarectal administration of sodium deoxycholate (SDC) enhances experimental colorectal carcinogenesis, an effect that is partly vitiated by oral metronidazole. The effect of topical SDC with or without concurrent metronidazole on colorectal cell proliferation was explored in male Sprague-Dawley rats (n = 30) allocated to five groups. Two groups received thrice weekly intrarectal instillations of 1 ml N saline or 1 ml 0.12 M SDC. A third group received SDC plus metronidazole 22.5 mg/kg/day in the drinking water. Controls had no instillations or metronidazole alone. At time of killing (10 weeks), crypt cell production rate (CCPR) was determined by the stathmokinetic technique for four large-bowel segments. Saline had no significant effect on colorectal CCPR but SDC produced increases throughout, varying from 53% in the proximal colon to 222% in the rectum (P less than 0.01). Metronidazole did not reduce this effect, although given alone it reduced colonic CCPR by 40 to 50%. The direct tropic effect of bile acids could largely explain their cocarcinogenic properties. Since metronidazole does not prevent this increase in cell proliferation, its mildly protective role against cancer may reflect the presence of fewer anaerobes capable of degrading bile acids to carcinogenic metabolites.

Topics: Administration, Rectal; Animals; Cell Division; Colonic Neoplasms; Deoxycholic Acid; Male; Metronidazole; Rats; Rats, Inbred Strains; Rectal Neoplasms

A small amount (50-200 microM) of deoxycholate (DOC), a colon tumor-promoting bile acid, did not show a direct effect on protein kinase C activity in a cell-free system, but enhanced fibroblast growth factor (FGF)-induced diacylglycerol formation and protein kinase C activation in Swiss 3T3 cells. DOC potentiated both reactions induced by submaximal doses of FGF but showed little effect on the maximal levels of the reactions. DOC alone was inactive in eliciting both reactions in the absence of FGF. DOC did not affect the binding of FGF to the cells. Since it has been described that diacylglycerol serves as a messenger for the activation of protein kinase C in the action of FGF in Swiss 3T3 cells [(1985) FEBS Lett. 191, 205-210], these results suggest that a small amount of DOC increases the sensitivity to FGF of diacylglycerol formation and thereby potentiates protein kinase C activation in this cell line. This action of DOC was in marked contrast to that of 12-O-tetradecanoylphorbol-13-acetate, a potent tumor-promoting phorbol ester, which directly activated protein kinase C in cell-free and intact cell systems.

Topics: Animals; Cell Line; Cell-Free System; Colonic Neoplasms; Deoxycholic Acid; Diglycerides; Drug Synergism; Enzyme Activation; Fibroblast Growth Factors; Glycerides; Mice; Phosphorylation; Protein Kinase C; Tetradecanoylphorbol Acetate

In Swiss 3T3 cells, colon tumor-promoting deoxycholate (DOC) enhanced DNA synthesis which was induced by fibroblast growth factor (FGF) in the presence of insulin. This effect was observed only when DOC was added within 10 h after the addition of FGF. DOC by itself did not induce DNA synthesis irrespective of the presence or absence of insulin. Similar results were obtained with other colon tumor-promoting bile acids such as cholate, chenodeoxycholate and taurocholate. In contrast to these bile acids, 12-O-tetradecanoylphorbol-13-acetate (TPA) induced DNA synthesis fully without FGF in the presence of insulin. DOC did not affect TPA-induced DNA synthesis. Prolonged treatment of the cells with phorbol-12,13-dibutyrate caused the down-regulation of the phorbol ester receptor and rendered the cells unresponsive to TPA. In these cells, FGF still induced DNA synthesis in the presence of insulin, but the maximal level was reduced to about one third of that in the control cells. DOC did not enhance this DNA synthesis any more. DOC did not alter the binding of FGF to the cells. These results indicate that colon tumor-promoting bile acids enhance the mitogenic action of FGF and thereby stimulate DNA synthesis, although the phorbol ester substitutes for the mitogenic action of FGF.

Topics: Animals; Bile Acids and Salts; Carcinogens; Cell Line; Colonic Neoplasms; Deoxycholic Acid; DNA; Fibroblast Growth Factors; Insulin; Mice; Phorbol Esters; Thymidine

Bile acids have been implicated in carcinogenesis of the large bowel, and since epidemiological, clinical and histopathological studies suggest a link between adenomatous polyps and cancer of the large bowel, fecal bile acid profiles were studied in 33 patients with adenomatous polyps of the large bowel and these data were analyzed with particular reference to the distribution, multiplicity, size and degree of dysplasia of the polyps. The more polyps and the greater the severity of dysplasia, the higher was the excretion of total bile acids (mean mumol/day: single vs multiple polyps, 344.8 vs 369.1; mild vs moderate vs severe dysplasia, 347.5 vs 370.0 vs 399.3). However, in patients with larger polyps, total fecal bile acid excretion tended to be lower (mean mumol/day: large vs small polyps, 267.7 vs 389.5). These differences were not statistically significant. When fecal bile acid profiles were analyzed with respect to the extent of bacterial metabolism determined from the degree of dehydroxylation and oxidoreduction, there was a large variation with no consistency in relation to the factors studied among the polyp patients. Deconjugation of bile acids in feces was almost complete without difference among the patients. These results seem to indicate that the significance of bile acid in the development of adenomatous polyps in Japanese subjects is likely to be small.

Topics: Adult; Aged; Bile Acids and Salts; Chenodeoxycholic Acid; Cholic Acid; Cholic Acids; Colon; Colonic Neoplasms; Deoxycholic Acid; Feces; Female; Humans; Intestinal Polyps; Intestine, Large; Japan; Lithocholic Acid; Male; Middle Aged; Neoplasms, Multiple Primary; Rectal Neoplasms; Rectum; Statistics as Topic

The mechanism whereby bile acids promote colon tumor development was studied. Bile acids increase intestinal ornithine decarboxylase (ODC), an effect that is suppressed by indomethacin, an inhibitor of prostaglandin (PG) synthesis. Male Sprague-Dawley rats were pretreated with 0.002% indomethacin solution in drinking water for 3 days, then given a single intrarectal instillation of 20 mg of deoxycholate and/or 1 mg of PGE2. Four hours later, the rats were killed, and the ODC activity was measured in the mucosa of the distal large bowel. ODC was significantly lower in rats given indomethacin plus deoxycholate than in those given deoxycholate alone, but it was significantly higher in rats treated with indomethacin and PGE2 plus deoxycholate. Without deoxycholate, indomethacin plus PGE2 did not elevate ODC compared with indomethacin alone or no treatment. Indomethacin reduced the colonic mucosal PG level. Thus, PGE2 mediates the deoxycholate-induced colonic mucosal ODC activity, and overcomes the inhibition of this enzyme activity by indomethacin. It is concluded that the anti-promoting effect of indomethacin in colon carcinogenesis, previously demonstrated, may result from the indomethacin inhibition of PG synthesis.

Topics: Animals; Cocarcinogenesis; Colon; Colonic Neoplasms; Deoxycholic Acid; Dinoprostone; Enzyme Induction; Indomethacin; Intestinal Mucosa; Male; Ornithine Decarboxylase; Ornithine Decarboxylase Inhibitors; Prostaglandins E; Rats; Rats, Inbred Strains

Epidemiological investigations have shown an association between the incidence of colonic cancer, dietary habits, and bile acid metabolism. We analyzed the fecal bile acid excretion pattern in 23 patients with colonic carcinoma and in 21 controls. We determined the total bile acid concentration, the concentration of individual bile acids as a measure for bacterial degradation, and the degree of sulfation. Separation of nonsulfated and sulfated bile acids was achieved by the lipophilic anion-exchanger DEAP-Sephadex-LH 20, quantification of individual bile acids by gas-liquid chromatography. Corresponding with a significantly lower stool mass per day, colonic cancer patients had a lower daily bile acid excretion. But we found no statistically significant difference between the groups in the fecal concentration of total or individual bile acids or their mode of conjugation. There was a wide variation of total bile acid concentration within each group. Most bile acids were expectedly in the free state, only a low percentage in the glycine- or taurine-conjugated form. The sulfated fraction was small and not different in the two groups. Although our data do not refute the hypothesis of bile acids being implicated in the pathogenesis of colorectal cancer, they do not support it.

Topics: Bile Acids and Salts; Chenodeoxycholic Acid; Cholic Acid; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Feces; Female; Humans; Intestinal Mucosa; Lithocholic Acid; Male; Middle Aged; Ursodeoxycholic Acid

It has previously been observed that 25% of human colorectal cancers contain specific receptors to deoxycholic acid (DCA). In the present study, the effect of intrarectal instillation of DCA on tumour number, distribution, size, and DCA receptor status was measured in rats receiving the colorectal carcinogen, azoxymethane. Rats treated with azoxymethane and intrarectal DCA developed significantly more colorectal cancers than rats receiving azoxymethane and intrarectal saline (median 11.5, range 8-17 vs. median 6.0, range 3-9 tumours/rat, respectively, p less than 0.01). This reflected a significantly higher number of tumours in the distal colon of the DCA-treated group (median 8.0, range 5-10 tumours/rat) compared to the saline-treated group (p less than 0.01). In those rats receiving DCA and azoxymethane, 5 of 12 tumours tested were found to be DCA receptor-positive, compared with only 1 of 11 in the saline and azoxymethane group. These results confirm the belief that DCA acts as a tumour promoter, and suggest a possible role for DCA receptors.

Topics: Animals; Azoxymethane; Colonic Neoplasms; Deoxycholic Acid; Disease Models, Animal; Male; Rats; Rats, Inbred Strains; Receptors, Steroid; Rectal Neoplasms

Bile acids are supposed to promote colonic cancer. In Crohn's disease, colonic carcinomas are relatively rare. We, therefore, compared ileal and right colonic mucosal bile acids analysed by gas-liquid chromatography in 8 patients with ileal Crohn's disease (14-48 yrs.) and 7 patients with right colonic carcinoma (28-77 yrs.) who underwent surgery. In both ileal and colonic mucosa, nonsulphated bile acid concentrations were somewhat higher in Crohn's disease (20.98 micrograms/g +/- 4.77 SEM; 12.09 micrograms/g +/- 2.55) than in colonic carcinoma (16.06 micrograms/g +/- 3.46; 7.75 micrograms/g +/- 4.28). In ileal mucosa, percentages of lithocholic and deoxycholic acids were slightly higher in colonic carcinoma (3.9%; 23.2%) than in Crohn's disease (1.1%; 14.9%). In colonic mucosa, carcinoma patients had more lithocholic (7.6%) and less deoxycholic acid (11.9%) than patients with Crohn's disease (1.7%; 20.3%). Bile acid sulphate esters were similar in both diseases (ca. 3.0 micrograms/g in ileal, 1.4 micrograms/g in colonic mucosa). Our results show that ileal and right colonic mucosal nonsulphated bile acids tend to be even lower in right colonic carcinoma than in Crohn's disease. This agrees well with our earlier findings of low mucosal bile acid concentrations in patients with left colonic carcinoma (Tokai J Exp Clin Med 8: 59-69, 1983) and does not support the assumption that bile acids are envolved in right colonic carcinogenesis.

Topics: Adolescent; Adult; Aged; Bile Acids and Salts; Chenodeoxycholic Acid; Cholic Acids; Colon; Colonic Neoplasms; Crohn Disease; Deoxycholic Acid; Female; Humans; Ileitis; Ileum; Intestinal Mucosa; Lithocholic Acid; Male; Middle Aged; Ursodeoxycholic Acid

Topics: Animals; Colonic Neoplasms; Deoxycholic Acid; Feces; Humans; Methylcholanthrene; Rats

Topics: Animals; Chenodeoxycholic Acid; Cholecystectomy; Cholelithiasis; Cholesterol; Colonic Neoplasms; Deoxycholic Acid; Female; Humans; Male; Risk; Ursodeoxycholic Acid

Bile acids enhance colorectal carcinogenesis in animals and man, perhaps after degradation by faecal anaerobes. The promotional effect of sodium deoxycholate (SDC) and its relationship to bacteria was examined in male Sprague-Dawley rats (n = 115) which had received a 6-week course of azoxymethane (total dose 90 mg kg-1 s.c.) Two groups received 3 X weekly intrarectal (i.r.) instillations of N saline or 0.12 M SDC for 18 weeks. Another group received SDC i.r. plus metronidazole (22.5 mg kg-1) daily in the drinking water. Controls had no instillations or metronidazole alone. By 28 weeks SDC had increased mean colonic crypt depth by 9% (P less than 0.001), and had almost trebled colorectal tumour yields from 2.4 +/- 0.4 per rat (mean +/- s.e.) in controls to 6.4 +/- 0.5 (P less than 0.001). Tumour yields after SDC + metronidazole (4.2 +/- 0.5) remained 75% higher than in controls (P less than 0.01) but were 33% less than after SDC alone (P less than 0.01), and the increase in crypt depth was maintained at 7% (P less than 0.001). Neither metronidazole alone nor saline i.r. had any effect on tumour yield, but metronidazole alone reduced crypt depth by 9% (P less than 0.001). Deoxycholate is a potent cocarcinogen and also stimulates mucosal hyperplasia. Metronidazole reduces its tumour-promoting effect, suggesting that faecal anaerobes are important in bile acid cocarcinogenesis.

Topics: Animals; Azoxymethane; Cocarcinogenesis; Colonic Neoplasms; Deoxycholic Acid; Intestines; Male; Metronidazole; Rats; Rats, Inbred Strains; Rectal Neoplasms

The carcinogen 3-methylcholanthrene can be produced from deoxycholic acid and is postulated by some investigators to play a role in the pathogenesis of colon carcinoma. The small quantities of this compound which could be carcinogenic have been difficult to measure in feces because of many potentially interfering compounds. Using 3-[6-14C]methylcholanthrene as an internal standard, petroleum ether extraction, C-18 SepPak separation, preparative high performance liquid chromatography, and gas-liquid chromatography-mass spectrometry with selected ion monitoring, we developed an assay capable of detecting less than 35 ng of 3-methylcholanthrene per gram of stool. Application of this technique to stools of five patients with colon carcinoma and two normal controls revealed no detectable 3-methylcholanthrene in any stool sample. This negative result was confirmed by incubating radiolabeled cholic acid in fecal homogenates. Although greater than 90% of this radiolabeled bile acid was converted to deoxycholic acid, none of the radioactivity was found in the thin-layer chromatography fraction corresponding to 3-methylcholanthrene. These observations provide evidence against a role for 3-methylcholanthrene in pathogenesis of human colon carcinoma. Similar assays could be used for analysis of other carcinogens in stool samples.

Topics: Cholic Acid; Cholic Acids; Chromatography, High Pressure Liquid; Colonic Neoplasms; Deoxycholic Acid; Feces; Gas Chromatography-Mass Spectrometry; Humans; Methylcholanthrene; Microchemistry

Bile acids are thought to be involved in both the aetiology and development of colorectal cancer. In this study the existence of specific bile acid receptor proteins has been postulated. A receptor assay which involved labelling with 14C-deoxycholic acid was performed as well as autoradiography using 3H-deoxycholic acid. In an initial study resected colorectal cancer and adjacent histologically normal colorectal mucosa from 39 patients were studied, as were samples of normal gastric mucosa, cancers and benign colorectal tumours. Specific receptors to deoxycholic acid were detected in 12 (30.8 per cent) of the colorectal cancers, but in only 1 (2.6 per cent) of the samples from normal colorectal mucosa (X2 = 11.16, P less than 0.005). No deoxycholic acid receptors were detected in any other tissue studied. Autoradiographs of colorectal cancers showed binding of 3H-deoxycholic acid in receptor-positive tumour tissue. These findings might provide some explanation for the evidence linking bile acids with the disease.

Topics: Autoradiography; Colonic Neoplasms; Deoxycholic Acid; Gastric Mucosa; Humans; Intestinal Polyps; Receptors, Cell Surface; Receptors, Steroid; Rectal Neoplasms; Stomach Neoplasms

A promoting effect of large bowel contents on colonic carcinogenesis as seen in the animal model is still incompletely explored in man. We investigated simultaneously deoxycholate absorption (as marker of colonic mucosal exposure to tumour promoting bile salt metabolites), mouth-anus transit time, and the ratio of anaerobic to aerobic bacteria in stool in 10 persons with colonic adenomas and in 10 age matched control subjects. We found that anaerobic/aerobic ratios and colonic deoxycholate absorption were higher in patients with colonic adenomas (p less than 0.002 and p less than 0.001) and that these parameters were clearly interrelated, which also applied to intestinal transit times and the anaerobic/aerobic ratios. These data are consistent with a promoting effect of the intracolonic environment on development of adenomas in man. Long term induction of a more aerobic colon flora and shortening of intestinal transit time may diminish bile-salt induced tumour promotion in adenoma patients.

Topics: Adenoma; Bacteria; Colon; Colonic Neoplasms; Deoxycholic Acid; Feces; Female; Humans; Intestinal Absorption; Male; Middle Aged; Risk; Time Factors

Because the composition of faeces modulates colorectal carcinogenesis, promotional effects of the secondary bile salt sodium deoxycholate (SDC) were compared with those of dilute homogenised faeces (12.5% w/v) or saline alone in rat colon isolated from the faecal stream as a Thiry-Vella fistula (TVF). Each fluid was used to irrigate a group of TVFs 3 times per week for 12 weeks. Other rats had TVF without irrigation or colonic transection and reanastomosis (sham TVF). Operations followed a 6-week course of azoxymethane injections. At sacrifice 15 weeks postoperatively crypt depth and tumour yield were reduced to the same extent in both the non-irrigated TVFs and the SDC-irrigated TVFs, when compared to shams. Irrigation with faeces and saline completely restored crypt depth and partly restored tumour yields to the levels in shams. Tumours were smaller in the SDC group than in the other 4 groups. While tumours developed mainly in the left colon of shams, there was significantly more even distribution in the TVFs. Exclusion of the colon from the faecal stream leads to mucosal hypoplasia and impaired carcinogenesis. Irrigation with faeces or saline partly reverses these changes. Deoxycholate has no such effect and clearly is not co-carcinogenic in this model.

Topics: Animals; Azoxymethane; Body Weight; Cocarcinogenesis; Colonic Neoplasms; Deoxycholic Acid; Feces; Intestinal Neoplasms; Intestines; Male; Rats; Rats, Inbred Strains; Therapeutic Irrigation

The effect of a deoxycholic acid instillation on colonic epithelium was investigated and compared with the effect of an intervention scheme in which deoxycholic acid (DCA) treated mice received oral supplements of calcium lactate. The morphology of colonic tissue exposed to DCA was markedly affected when compared to that of untreated controls. Inflammation, edema, and necrosis preceded elevated numbers of mitotic figures appearing 24 h to 48 h after DCA treatment. Proliferative activity as measured by tritiated thymidine uptake and autoradiography was increased 2.5-fold in colonic crypts of DCA treated mice. In contrast mice receiving multiple oral supplements of calcium lactate showed minimal tissue necrosis due to DCA administration and the frequency of mitotic events and cellular proliferation activity remained similar to levels seen in untreated controls. Sequestration of bile acids by calcium salts may provide a scheme for inhibiting the untoward effects of bile acids on the colonic epithelium and a mechanism for blocking the reported co-carcinogenic activity of these agents.

Topics: Animals; Calcium; Carcinogens; Cell Division; Colon; Colonic Neoplasms; Deoxycholic Acid; DNA Replication; Epithelium; Female; Mice; Mice, Inbred C57BL; Mitosis; Neoplasms, Experimental

Topics: Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Feces; Female; Greece; Humans; Male; Risk

After cholecystectomy the concentration of secondary bile acids in the bile increases. These bile acids have been incriminated in the pathogenesis of carcinoma of the colon. Hence the hypothesis that cholecystectomy predisposes to the development of carcinoma of the colon. To test this hypothesis, 1681 residents of Rochester, Minnesota (460 males and 1221 females), who underwent cholecystectomy during 1950-69, were followed up. Carcinoma of the colon developed in a higher-than-expected number of patients. However, the association was significant only in females (relative risk 1.7; 95% confidence interval 1.1-2.5) and even stronger for right-sided carcinoma of the colon (relative risk 2.1; 95% confidence interval 1.1-3.6). These data support the hypothesis that cholecystectomy may be a predisposing factor in the development of cancer of the colon in women.

Topics: Aged; Bile; Cholecystectomy; Colonic Neoplasms; Deoxycholic Acid; Female; Humans; Lithocholic Acid; Male; Middle Aged; Risk; Sex Factors

It has been suggested that transformation of secondary bile acids into (co)carcinogenic compounds may have a role in the development of cancer of the large bowel. Because of age dependent differences of this disease we undertook a study of cholic and deoxycholic acid metabolism of eleven young adults (group A, 20-30 years old) and eleven elderly persons (group B, 55-75 years old) with a double isotope dilution method. Daily food intake was standardized individually and gut transit time measured with radioopaque pellets and labelled chromium chloride. The 7 alpha-dehydroxylation fractions (the ratio of deoxycholic acid input rate from the large bowel to cholic acid synthesis rate) were higher in group B (P less than 0.01) due to higher deoxycholic acid input rates (P less than 0.005), especially when individuals from both groups with rapid gut transit were compared. As contributory factor was recognized the higher fractional turnover rate of cholic acid in group B. Pool sizes and synthesis rates of cholic acid and gut transit times were similar. In group A, but not in B, gut transit times correlated with deoxycholic acid input rates (P less than 0.01). The differences in bile acid metabolism may be related to a more effective colonic absorption of deoxycholic acid in the elderly persons with a concomitant decrease of active ileal absorption of cholic acid in the elderly persons. Differences in diet or gut transit time between both groups do not seem to be the underlying mechanism.

Topics: Adult; Age Factors; Aged; Bile Acids and Salts; Cholic Acids; Cocarcinogenesis; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet; Female; Humans; Intestinal Absorption; Kinetics; Male; Middle Aged; Risk

The effects of two agents, 12-O-tetradecanoylphorbol-13-acetate (TPA) and deoxycholic acid (DOC), which act as tumor promoters in the gastrointestinal epithelium of experimental animals, were compared using primary cultures of human premalignant colonic epithelial cells at different stages in tumor progression. Both DOC and TPA enhanced the size of the proliferative fraction in colonies of early-stage premalignant cells, with DOC providing more stimulation. TPA-treated intermediate- and late-stage premalignant cells elongated and then disrupted the monolayer by forming rills several cells in thickness and then multicellular clusters. This multilayering was reminiscent of the areas of carcinoma found within adenomas. DOC had no such effects on morphology. Cell clustering was concomitant with secretion of a protease with characteristics of a plasminogen activator. Premalignant cells secreted severalfold higher levels of protease in response to TPA than did either TPA-treated primary cultures of colonic adenocarcinomas or established colon carcinoma cell lines. These results suggest that (a) DOC and TPA act sequentially during tumor promotion and (b) cell clustering and protease release may be associated with the transition of premalignant epithelial cells to colonic carcinoma.

Topics: Cell Division; Cell Line; Cell Transformation, Neoplastic; Cells, Cultured; Colonic Neoplasms; Deoxycholic Acid; DNA Replication; Epithelium; Humans; Peptide Hydrolases; Phorbols; Plasminogen Activators; Precancerous Conditions; Protease Inhibitors; Tetradecanoylphorbol Acetate

In order to examine their bile acid transforming capacities, lecithinase-lipase-negative Clostridia, 40 strains, isolate from the feces of patients with large bowel cancer, were cultivated in Schaedler broth containing either cholic, chenodeoxycholic or deoxycholic acid (250 muM). Gas chromatographic analysis of bile acids as hexafluoroisopropylester-trifluoroacetates [on QF-1] showed that 14 strains (35%) attacked cholic acid and 13 strains (32%) chenodeoxycholic acid. Deoxycholic acid, however, was not attacked. About half of the strains transformed cholic and chenodeoxycholic acids as well to one or two products respectively. The metabolites were identified as 3 alpha, 12 alpha-dihydroxy-7-keto-5 beta-cholanoic acid, 3 alpha, 7 beta, 12 alpha -trihydroxy-5 beta-cholanoic acid resp. 3 alpha-hydroxy-7-keto-5 beta-cholanoic acid, and 3 alpha, 7 beta-dihydroxy-5 beta-cholanoic acid (ursodeoxycholic acid) by gas chromatography an combined gas chromatography-mass spectrometry. The Clostridial strains tested here are the first which have proved able to epimerize the 7 alpha-hydroxyl groups of bile acids. We could, however, find no relevance to the etiology of large bowel cancer.

Topics: Bile Acids and Salts; Biotransformation; Chenodeoxycholic Acid; Cholic Acid; Cholic Acids; Clostridium; Colonic Neoplasms; Deoxycholic Acid; Feces; Humans; Lipase; Phospholipases

During the last years bile acids have gained more and more clinical importance. They play a decisive part in intestinal fat resorption. Increased bile acid content in the colon will result in diarrhea. By determination of serum bile acids the liver function can be judged exactly. It seems probable that bile acids take part in the pathogenesis of gastritis gastric ulcer and colonic cancer. By administration of chenodeoxycholic acid and ursodeoxycholic acid dissolution of cholesterol stones within the gall bladder is possible.

Topics: Bile Acids and Salts; Chenodeoxycholic Acid; Cholelithiasis; Colonic Neoplasms; Deoxycholic Acid; Gastritis; Humans; Intestinal Absorption; Liver Diseases; Oxalates; Stomach Ulcer

Some workers have associated fecal bile acids with colon cancer frequency. They suggest that the risk for colon cancer increases with a rise in the level of total and degraded fecal bile acids. The Japanese in Hawaii, who are at high risk for this cancer, had higher concentrations of deoxycholic acid (a degraded bile acid) in their fecal specimens than did the people in Akita, Japan, who are at low risk. However, the findings for the other bile acids were unremarkable or inconsistent. These data were suggestive, but not strongly supportive, of a relationship between fecal bile acid patterns and colon cancer risk.

Topics: Adult; Aged; Bile Acids and Salts; Colonic Neoplasms; Deoxycholic Acid; Diet; Epidemiologic Methods; Feces; Female; Hawaii; Humans; Japan; Male; Middle Aged; Risk

Topics: Animals; Bile Acids and Salts; Cell Division; Cells, Cultured; Chenodeoxycholic Acid; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Lithocholic Acid; Liver; Rats

Fecal samples of 165 Japanese men in Hawaii, age 43 to 74, were analyzed for bile acid content by their conversion to the methyl ester and the trimethylsilyl ether derivative followed by separation on a gas chromatograph. The arithmetic mean of total bile acids for the 165 specimens was 10.96 mg/g dry weight feces. Each of the following bile acids was detectable in over 77% of the fecal specimens: cholic, deoxycholic, lithocholic, and cholanic acid. The intake of Western foods was not positively correlated with the fecal content of secondary or modified bile acids, even though other workers have observed that these bile acids predominated in persons from Westernized countries. Two of the Japanese foods were negatively correlated with the levels of modified bile acids, which suggested that these foods contributed to a decrease in modified bile acids in fecal specimens. Fecal bile acid measurements appeared to be associated with age, but not with weight, height, or serum cholesterol levels.

Topics: Adult; Age Factors; Aged; Bile Acids and Salts; Carboxylic Acids; Cholanes; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Diet; Feces; Hawaii; Humans; Japan; Life Style; Lithocholic Acid; Male; Middle Aged

The capacity of enteric bacteria (E. coli, Salmonella, Pseudomonas, Shigella and Klebsiella) to catalyze the covalent binding of benzo(a)pyrene (BP), cholic acid, deoxycholic acid and cholesterol was investigated. In general, these bacteria were incapable of activating BP to a covalently bound product with calf thymus DNA. Metabolism studies of BP by fluorometric assay failed to indicate any accumulation of BP-3-hydroxy in the incubation medium. Detailed metabolic investigation with high-pressure liquid chromatography indicated that these bacteria did not produce any known metabolites which are formed by mammalian systems. However, radioactivity was detected in all fractions, suggesting that the bacteria were readily metabolizing BP into smaller molecules for energy and carbon sources. Although the enteric bacteria did not metabolize BP into known metabolites, some were capable of activating cholesterol, cholic acid and deoxycholic acid to covalently bound products with DNA. The binding data with cholesterol and bile acids also suggested that the binding process required NADPH as a cofactor because binding level was rather low without NADPH.

Topics: Benzopyrenes; Cholesterol; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; DNA; Enterobacteriaceae; Escherichia coli; Klebsiella; NADP; Pseudomonas; Salmonella; Shigella

The influence of cholecystectomy on the development of carcinoma of the colon is investigated. The experimental results show a significantly increased rate of carcinoma of the colon induced by subcutaneous injection of 1,2-Dimethylhydrazin (DMH) in the mouse after cholecystectomy. After 10 weekly injections of 15 mg/kg DMH, 70% of the animals with cholecystectomy developed carcinoma. Only 16% of the mice with similar treatment but without cholecystectomy had carcinoma. The cocarcinogenic effect of cholecystectomy is assumed to be due to the increased production of secondary bile salts by the colonic bacteria and the lacking of the resorptive function of the gallbladder for some carcinogenic substances passing through the liver. The background of this experimental studies are the clinical findings that 10% of patients with carcinoma of the large bowel had previous cholecystectomy.

Topics: Animals; Cholecystectomy; Colonic Neoplasms; Deoxycholic Acid; Dimethylhydrazines; Female; Mice; Neoplasms, Experimental

The effect of type (corn oil or lard) and quantity (5 or 20%) of dietary fat and 1,2-dimethylhydrazine (DMH) on the composition of biliary bile acids, fecal bile acids, and neutral sterols was studied in rats exposed to a given regimen for two generations prior to s.c. treatment with DMH for 20 weeks. Biliary excretion of total bile acids as well as cholic acid, beta-muricholic acid, ursodeoxycholic acid, and deoxycholic acid was higher in rats fed a diet containing 20% corn oil or lard than it was in rats fed diets containing 5% corn oil or lard. Treatment of animals with DMH produced an increase in biliary total bile acids, cholic acid, hyodeoxycholic acid, and deoxycholic acid irrespective of diets. High-fat (corn oil or lard at 20% level) intake was associated with an increased excretion of fecal neutral sterols and bile acids. The excretion of deoxycholic acid, lithocholic acid, and 12-ketolithocholic acid was increased in rats fed high-fat diets. The source of fat had no major influence on the excretory pattern of cholesterol metabolites and bile acids. DMH-treated animals excreted higher levels of fecal coprostanol, coprostanone, deoxycholic acid, lithocholic acid, and 12-ketolithocholic acid than did controls.

Topics: Animals; Bile; Bile Acids and Salts; Cholesterol; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Dimethylhydrazines; Feces; Female; Hydrazines; Liver; Male; Neoplasms, Experimental; Oils; Rats; Rats, Inbred F344; Sterols; Zea mays

Topics: Bacteroides; Bile Acids and Salts; Biodegradation, Environmental; Chemical Phenomena; Chemistry; Chenodeoxycholic Acid; Cholic Acids; Chromatography, Gas; Chromatography, Thin Layer; Colonic Neoplasms; Deoxycholic Acid; Evaluation Studies as Topic; Humans; Humidity; Mass Spectrometry; Steroids; Temperature

Topics: Absorption; Arteriosclerosis; Bile Acids and Salts; Cellulose; Cholelithiasis; Cholesterol; Colonic Neoplasms; Constipation; Deoxycholic Acid; Dietary Fiber; Humans; Hypercholesterolemia; Intestinal Absorption; Lipid Metabolism; Lithocholic Acid; Pectins; Water

The promoting effect of sodium deoxycholate (DC) on colon carcinogenesis was studied in female F344 germfree rats. Animals received intrarectal (ir) instillations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 4 weeks (total dose, 16 mg/rat), then weekly ir doses of DC (total dose, 3 g/rat); the rats were autopsied 52 weeks after the first injection. DC increased the number of MNNG-induced colon adenocarcinomas. No tumors were in the colons of germfree rats given DC alone. It was concluded that DC (present in high concentrations in human stools) had a promoting effect on colon carcinogenesis in rats.

Topics: Adenocarcinoma; Animals; Colonic Neoplasms; Deoxycholic Acid; Female; Methylnitronitrosoguanidine; Neoplasms, Experimental; Nitrosoguanidines; Rats; Rats, Inbred F344

Topics: Bile Acids and Salts; Chenodeoxycholic Acid; Cholestanol; Cholesterol; Cholic Acids; Colectomy; Colonic Neoplasms; Deoxycholic Acid; Feces; Humans; Ileum; Intestinal Polyps; Lithocholic Acid; Neoplasms, Multiple Primary; Rectum; Sterols; Syndrome

Topics: Bile Acids and Salts; Carcinogens; Cholesterol; Colon; Colonic Neoplasms; Coronary Disease; Deoxycholic Acid; Diet; Dietary Fats; Enterobacteriaceae; Feces; Humans; Lipid Metabolism; Male; Middle Aged

Topics: Africa; Americas; Asia; Bacterial Infections; Bile Acids and Salts; Carcinogens; Colon; Colonic Neoplasms; Deoxycholic Acid; Diet; Dietary Fats; Europe; Feces; Gastrointestinal Motility; Humans; Intestinal Absorption; Methylcholanthrene

Topics: ABO Blood-Group System; Adult; Anemia, Pernicious; Bacteria; Bile Acids and Salts; Carcinogens; Colonic Neoplasms; Deoxycholic Acid; Diet; Feces; Female; Gastritis; Gastrointestinal Neoplasms; Humans; Male; Middle Aged; Sex Factors; Stomach Neoplasms; United States

Topics: Anaerobiosis; Bacteroides; Brain; Cholic Acids; Colonic Neoplasms; Culture Media; Deoxycholic Acid; Glycocholic Acid; Growth Substances; Hemin; Humans; Species Specificity; Stimulation, Chemical; Tissue Extracts

Topics: Animals; Bile Acids and Salts; Body Weight; Carbon Radioisotopes; Carcinogens; Cholesterol; Cholic Acids; Colonic Neoplasms; Deoxycholic Acid; Dietary Fats; Feces; Hydrazines; Lithocholic Acid; Male; Rats; Sterols

Topics: Animals; Carcinogens; Colon; Colonic Neoplasms; Constipation; Deoxycholic Acid; Diet; Humans; Mice; Rabbits