deoxycholic-acid and Intestinal-Neoplasms

Increased levels of intestinal bile acids (BAs) are a risk factor for colorectal cancer (CRC). Here, we show that the convergence of dietary factors (high-fat diet) and dysregulated WNT signaling (APC mutation) alters BA profiles to drive malignant transformations in Lgr5-expressing (Lgr5

Topics: Animals; Bile Acids and Salts; Cell Line; Cell Proliferation; Colorectal Neoplasms; Deoxycholic Acid; Gene Expression Regulation, Neoplastic; Humans; Intestinal Neoplasms; Intestines; Liver; Mice; Mice, Inbred C57BL; Neoplastic Stem Cells; Organoids; Receptors, Cytoplasmic and Nuclear; Risk Factors; Signal Transduction; Taurocholic Acid; Wnt Signaling Pathway

Mechanisms by which gut luminal content regulates secretion and motility are ill understood. We evaluated whether neuroendocrine enterochromaffin (EC) cells act as luminal sensors for a wide variety of nutrients and defined the secretory mechanisms of this process. Pure (98-99%) FACS-sorted human EC cells and neoplastic EC cells (KRJ-I) were studied. RT-PCR identified transcripts for T2R1 (bitter), OR1G1 (class II olfactory) and trace amine (TAR1) G protein-coupled receptors (GPCRs) and transporters for glutamine (SNAT1/2), glucose (GLUT1/3/SGLT1), and bile salts (ABST). Glutamine and sodium deoxycholate stimulated 5-HT release (EC(50) = 0.002-0.2 microM; 2-fold release) but were 10-100 times more potent in neoplastic EC cells, which also secreted 6-13 times more 5-HT. Tastants (caffeine, tyramine, octopamine) and olfactants (thymol and eugenol) also stimulated normal and neoplastic EC cell 5-HT secretion (EC(50) = 1.2 nM to 2.1 microM and 0.05 nM to 0.1 microM release, respectively); 2-deoxyglucose and the artificial sweetener sucralose also stimulated (EC(50) = 9.2 and 0.38 nM). 5-HT release was associated with ERK phosphorylation (1.5-fold, P < 0.02) and could be inhibited by a somatostatin analog (IC(50) = 1 pM). Eleven secretory associated genes including the vesicle docking inhibitor STXBP3 were upregulated in response to glutamine and bile salt stimulation in neoplastic EC cells. Targeting STXBP3 expression by use of antisense knockdown significantly (P < 0.05) reduced 5-HT secretion. In conclusion, EC cells express GPCRs and transporters for luminal tastants, olfactants, glutamine, glucose, and bile salts. Activation includes a panel of secretory genes, ERK phosphorylation, and 5-HT secretion. Luminal EC cell regulation is likely to be as important as G cell regulation in gastric acid secretion; development of agents to target EC cell function is therefore a critical therapeutic goal.

Topics: Amino Acid Transport System A; Bile Acids and Salts; Caffeine; Carcinoid Tumor; Cell Line, Tumor; Deoxycholic Acid; Deoxyglucose; Enterochromaffin Cells; Extracellular Signal-Regulated MAP Kinases; Glucose Transport Proteins, Facilitative; Glutamine; Humans; Intestinal Neoplasms; Intestine, Small; Organic Anion Transporters, Sodium-Dependent; Receptors, G-Protein-Coupled; Receptors, Metabotropic Glutamate; Receptors, Odorant; Serotonin; Sodium-Glucose Transporter 1; Somatostatin; Sucrose; Symporters; Tyrosine

We examined the effect of hyodeoxycholic acid (HDCA) on plasma cholesterol levels and atherosclerosis in mice. In wild-type C57BL/6 mice, feeding increasing amounts of HDCA resulted in i) progressive decrease in dietary cholesterol absorption, ii) increased concentrations of HDCA in the gallbladder bile, iii) decreased liver cholesterol content, iv) increased liver cholesterol synthesis, and v) increased plasma concentrations of HDCA. In C57BL/6 LDL-receptor knockouts (LDLR-KO) the addition of HDCA to chow and a 0.5% cholesterol diet decreased their total plasma cholesterol levels by 21% and 62%, respectively, because of a decrease in VLDL and LDL cholesterol. Turnover studies showed that HDCA has no effect on VLDL removal from plasma. Furthermore, the addition of HDCA to chow- and 0.5% cholesterol-fed LDLR-KO mice decreased the aortic root atherosclerosis lesion area by 50% and 80%, respectively. Finally, we tested the effect of HDCA on intestinal tumor formation. Feeding C57BL/6 ApcMin mice with HDCA did not affect the number of tumors but decreased the tumor volume in these animals. These results suggest that HDCA might have beneficial effects in the treatment of increased plasma cholesterol levels and atherosclerosis.

Topics: Absorption; Animals; Arteriosclerosis; Bile; Cholesterol; Cholesterol, Dietary; Cholesterol, LDL; Cholesterol, VLDL; Deoxycholic Acid; Hydroxymethylglutaryl CoA Reductases; Intestinal Neoplasms; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptors, LDL

Recent studies have implicated protein kinase C (PKC) activation in drug resistance in vitro. PKC can be activated directly by phorbol-ester tumor promoters as well as by the bile acid deoxycholate. In this report, we demonstrate that deoxycholate, at concentrations that are chronically present in the lumen of the colon in vivo, mimicked phorbol-ester tumor promoters by protecting Adriamycin (ADR)-sensitive and multidrug-resistant (MDR) murine fibrosarcoma UV-2237M cells from ADR cytotoxicity. Deoxycholate also enhanced the resistance of the MDR cell line UV-2237M-ADRR to the cytotoxic effects of vincristine and vinblastine. In contrast to cytotoxic drug-selected MDR phenotypes, deoxycholate-induced drug resistance was transient and required continuous exposure to the bile acid. The protein kinase inhibitor H7 completely reversed the protection against ADR cytotoxicity conferred on UV-2237M-ADRR cells by deoxycholate, providing evidence that deoxycholate exerts its protective effects by a mechanism that involves stimulation of protein phosphorylation and not merely by detergent effects on membrane permeability. PKC consists of a family of at least seven isozymes with distinct modes of activation and substrate specificities. We previously reported that MDR UV-2237M cell lines contain higher levels of PKC activity than the parental ADR-sensitive UV-2237M cell line (O'Brian et al., FEBS Lett 246: 78-82, 1989). The present report shows that PKC-III is a major PKC isozyme in ADR-sensitive and MDR UV-2237M cell lines. Thus, the resistance to ADR induced by the phorbol esters in UV-2237M cell lines provides strong evidence that PKC-III activation confers protection against ADR on ADR-sensitive and MDR UV-2237M cell lines. Furthermore, since deoxycholate is an endogenous molecule in the colonic epithelium, our finding that physiological concentrations of deoxycholate can render cells more resistant to chemotherapeutic drugs in vitro may have implications for the biology and therapy of intestinal cancers.

Topics: Animals; Cell Division; Dactinomycin; Deoxycholic Acid; Doxorubicin; Drug Resistance; Fibrosarcoma; Intestinal Neoplasms; Isoenzymes; Mice; Phenotype; Phorbol Esters; Protein Kinase C; Tumor Cells, Cultured; Vinblastine; Vincristine

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

When testing 36 laboratory strains of the strictly anaerobic Bacteroides species B. vulgatus, B. fragilis, B. thetaiotaomicron, and B. distasonis, we found activities for degradation of cholate (3alpha, 7alpha, 12alpha-trihydroxy-5 beta-cholanoate) (1) and chenodeoxycholate (3alpha, 7alpha-dihydroxy-5 beta-cholanoate) (2) widely, but not universally distributed in these bacteria. The same strains were also tested for their metabolic activities in regard to deoxycholate (3alpha, 12alpha-dihydroxy-5 beta-cholanoate). These tests were performed with anaerobically growing cultures and with resting cells, incubated aerobically, in media of defined composition indicated in the foregoing papers. After precultivation in a medium containing bile and deoxycholate 22 of 35 strains (63 per cent), growing anaerobically, and 28 of 36 aerobically incubated tests (78 per cent) transformed deoxycholate. In summa the number of active strains was 30 of 36 (83 per cent). All active strains, produced one metabolite only, all metabolities had the same chromatographic properties as shown by analytical thin-layer chromatography in two solvent systems. However, it has still to be decided whether only one degradation product is formed from deoxycholate, corresponding to the transformation of chenodeoxycholate (2), since the chromatographic properties of the metabolites permit the formation of 3alpha-hydroxy-12-oxo- and/or 3-oxo-12alpha-hydroxy-cholanoate. Structural evidence, however, could hitherto not be demonstrated. The enzymatic activity, responsible for the metabolism, has to be induced, it is not identical with the activity oxidizing the 7alpha-hydroxyl group. No further details concerning enzyme induction and activity regulation have as yet been discovered. The side chain of deoxycholate can not be degraded by Bacteroides species, neither by anaerobically growing cultures nor by aerobically incubated resting cells.

Topics: Aerobiosis; Anaerobiosis; Bacteroides; Bacteroides fragilis; Chromatography, Thin Layer; Deoxycholic Acid; Humans; Intestinal Neoplasms; Species Specificity

Two groups of 20 male Sprague-Dawley rats each were given sc 8 mg azoxymethane/kg body weight and fed a normal diet or one high in beef fat. Control groups were not given azoxymethane. Fat-control animals did not excrete more total bile acids than did the normal-control group but did excrete more deoxycholic acid as the result of increased cholic acid degradation. Azoxymethane itself caused an increase in fecal bile acid concentratation but tended to reduce the level of cholic acid degradation. Fatty acid content in the feces increased in the animals on the fat diet but was not affected by azoxymethane. A fat-diet-dependent increase was apparent in total fecal neutral steroids and a carcinogen-dependent increase in cholesterol degradation. Dietary fat and bile steroids altered by gut microflora were important interrelated factors in the intestinal carcinogenic process of this animal model.

Topics: Animals; Azoxymethane; Bile Acids and Salts; Cholesterol; Cholic Acids; Cocarcinogenesis; Deoxycholic Acid; Dietary Fats; Fatty Acids; Feces; Intestinal Neoplasms; Male; Meat; Neoplasms, Experimental; Rats

Topics: Bile Acids and Salts; Cellulose; Cholelithiasis; Cholic Acids; Chromatography, Thin Layer; Deoxycholic Acid; Diet; Feces; Humans; Intestinal Neoplasms; Intestine, Large; Nigeria; Taurocholic Acid