linoleic-acid and Adenocarcinoma

During a study of the mechanism of cancer cachexia, a debilitating condition in which catabolism of host muscle and adipose tissue occurs, it has been observed that the process can be effectively reversed in vivo by the polyunsaturated fatty acid, eicosapentaenoic acid (EPA), but not by other PUFA of either the n-3 or n-6 series. In vitro studies showed that EPA blocked the action of a tumour-produced catabolic factor at the level of the adipocyte, and that the effect of EPA also extended to beta-adrenergic stimuli and polypeptide hormones. Again the effect was specific to EPA and appeared to arise from an inhibition of the elevation of cyclic AMP levels in adipocytes in response to varied stimuli. Using isoprenaline stimulated lipolysis as a model system we have shown that EPA has a direct inhibitory effect on isoprenaline-stimulated adenylate cyclase in isolated plasma membrane fractions with half maximal inhibition at a concentration of 165 microM. The inhibitory effect was specific for EPA and was not shown by docosahexaenoic or arachidonic acids. The inhibitory effect of EPA on adenylate cyclase showed properties similar to hormonal inhibition of the enzyme in that it was (i) GTP-dependent, (ii) non-competitive with isoprenaline, (iii) eliminated following treatment of either adipocytes or plasma membrane fractions with pertussis toxin, which is known to ADP-ribosylate the alpha-subunit of an inhibitory guanine nucleotide-regulatory protein (Gi), thus leading to its inactivation. This suggests that inhibition of cyclic AMP formation by EPA was due, at least in part, to a Gi-mediated inhibition of adenylate cyclase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenocarcinoma; Adenylyl Cyclases; Adipose Tissue; Animals; Cachexia; Colonic Neoplasms; Cyclic AMP; Dietary Fats; Eicosapentaenoic Acid; Enzyme Activation; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Gene Expression Regulation; Genes, ras; GTP-Binding Proteins; Humans; Isoproterenol; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Lipolysis; Mice; Neoplasms; Signal Transduction

The aim of this study was to determine the effects of some polyunsaturated fatty acids plus phytomelatonin from walnuts in the development of mammary gland adenocarcinoma.. BALB/c mice were fed a semisynthetic diet supplemented with either 6% walnut oil and 8% walnut flour containing phytomelatonin (walnut diet: WD); or 6% corn oil plus commercial melatonin (melatonin diet: MD), or the control group (CD), which received only 6% of corn oil. Membrane fatty acids of tumor cells (TCs) were analyzed by gas liquid chromatography, cyclooxygenase (COX) and lipoxygenase (LOX) derivatives, and plasma melatonin by high-performance liquid chromatography; apoptosis and tumor-infiltrating lymphocytes by flow cytometry.. TCs from the MD and WD mice showed significant decreases in linoleic acid compared with the CD group (P < 0.05). Significantly lower levels of LOX-[13(S)-HODE] were found in TCs from the MD and WD group than in CD (P < 0.0001). COX-[12(S)-HHT] was lower and 12 LOX-[12(S)-HETE] was higher in TCs from the MD group than form the WD and CD arms (P < 0.05). Plasma melatonin, apoptosis, tumor infiltration, and survival time were significantly lower in CD mice than in MD and WD mice (P < 0.05).. This study shows that melatonin, along with polyunsaturated fatty acids, exerts a selective inhibition of some COX and LOX activities and has a synergistic anti-tumor effect on a mammary gland adenocarcinoma model.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cyclooxygenase Inhibitors; Diet; Disease Models, Animal; Drug Synergism; Fatty Acids, Omega-3; Female; Juglans; Linoleic Acid; Lipoxygenase; Male; Melatonin; Mice, Inbred BALB C; Nuts; Phytotherapy; Prostaglandin-Endoperoxide Synthases

Lung cancer is the leading cause of cancer-related mortality. Surgical removal of the tumor at an early stage can be curative. However, lung cancer diagnosis at an early stage remains challenging. There is evidence that free fatty acids play a role in cancer development.. Serum samples from 55 patients with lung cancer were propensity matched with samples from 165 similar pulmonary patients without known cancer. Patients were propensity matched on age, sex, smoking history, family history of lung cancer, and chronic diseases that might affect free fatty acid levels.. Free fatty acids arachidonic acid (AA) and linoleic acid (LA) and their metabolites hydroxyeicosatetraenoic acids (HETEs)(5-HETE, 11-HETE, 12-HETE, and 15-HETE) were an estimated 1.8- to 3.3-fold greater in 37 patients with adenocarcinoma vs 111 patients without cancer (all P < .001). Areas under the receiver operating characteristic curve were significantly > 0.50, discriminating patients with lung cancer and control subjects for six of eight biomarkers and two of seven phospholipids tested, and ranged between 0.69 and 0.82 (all P < .001) for patients with lung cancer vs control subjects. AA, LA, and 15-HETE had observed sensitivity and specificity > 0.70 at the best cutpoint. Concentrations of free fatty acids and their metabolites were similar in 18 patients with squamous cell carcinoma and 54 control subjects without cancer.. Serum fatty acids and their metabolites demonstrate good sensitivity and specificity for the identification of adenocarcinoma of the lung.

Topics: Adenocarcinoma; Adult; Aged; Area Under Curve; Biomarkers; Case-Control Studies; Fatty Acids, Nonesterified; Fatty Acids, Unsaturated; Female; Humans; Hydroxyeicosatetraenoic Acids; Linoleic Acid; Lung Neoplasms; Male; Middle Aged; Phospholipids; Sensitivity and Specificity

In this study, we investigated the effects of linoleic acid (LA), a polyunsaturated fatty acid found in most vegetable oils and certain food products, on the growth of AGS human gastric adenocarcinoma cells. LA treatment resulted in a concentration-dependent growth inhibition of AGS cells by inducing apoptosis, as evidenced by the formation of apoptotic bodies, chromatin condensation, and the accumulation cells in the sub-G1 phase. LA treatment induced cyclin-dependent kinase inhibitor p21 in a p53-independent manner; however, this compound did not affect the cell cycle distribution. Reverse transcription-polymerase chain reaction and western blot analyses showed that treating the cells with LA caused the up-regulation of pro-apoptotic Bax expression and the down-regulation of anti-apoptotic Bcl-2 expression. The apoptosis of AGS cells by LA was found to be associated with an elevated Fas and Fas ligand expression in a concentration-dependent manner. Furthermore, a proteolytic activation of caspases (3, 8, and 9), and degradation/cleavage of poly(ADP-ribose) polymerase and phospholipase C-gamma 1 protein were noted in LA-treated AGS cells. The present results indicate that the Fas/Fas ligand pathway might be involved in LA-induced apoptosis of AGS cells.

Topics: Adenocarcinoma; Apoptosis; Caspases; Cell Division; Cell Line, Tumor; Enzyme Activation; Fas Ligand Protein; fas Receptor; Gene Expression; Humans; Linoleic Acid; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; Stomach Neoplasms; Type C Phospholipases

To study the effects of c9, t11-conjugated linoleic acid (c9, t11-CLA) on the critical enzyme (COX-2) and its product - prostaglandin E2 (PGE2) of linoleic acid metabolism path in human gastric adenocarcinoma cell line (SGC-7901).. Expression of COX-2 mRNA and protein were measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot, PGE2 was determined by radioimmunoassay (RIA).. At the concentrations of 25, 50, 100, 200 pmol/L, c9, t11-CLA suppressed the expression of COX-2 mRNA, protein and PGE.. COX-2 is involved anti-cancer action of c9, t11-CLA and is likely to act as an important target.

Topics: Adenocarcinoma; Cell Line, Tumor; Cell Proliferation; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Humans; Linoleic Acid; Linoleic Acids, Conjugated; RNA, Messenger; Stomach Neoplasms

Dietary heterocyclic aromatic amines (HCA) and polyunsaturated fatty acids (PUFA) are both believed to play a role in colon carcinogenesis, and are both substrate for the enzyme cyclooxygenase (COX). In HCA-7 cells, highly expressing isoform COX-2, we investigated the effects of PUFA on prostaglandin synthesis and DNA adduct formation by the HCA 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). Furthermore, we studied the role of COX, COX-2 in particular, and cytochrome P4501A2 (CYP1A2) by using the enzyme inhibitors indomethacin (IM), NS-398, and phenethyl isothiocyanate (PEITC), respectively. COX-mediated formation of prostaglandin E2 (PGE2) from linoleic acid (LA) showed that HCA-7 cells can convert LA into arachidonic acid (AA). Alternatively, eicosapentaenoic acid (EPA) was found to compete with AA for COX. Strongly decreased PGE2 levels by addition of IM demonstrated involvement of COX in PUFA metabolism. Both IM and NS-398 inhibited adduct formation by HCA to nearly the same extent, indicating involvement of COX-2 rather than COX-1, while CYP1A2 activity in HCA-7 cells was demonstrated by addition of PEITC. Overall, inhibiting effects were stronger for PhIP than for IQ. HCA-DNA adduct formation was stimulated by addition of PUFA, although high PUFA concentrations partly reduced this stimulating effect. Finally, similar effects for n-3 and n-6 fatty acids suggested that adduct formation may not be the crucial mechanism behind the differential effects of PUFA on colon carcinogenesis that have been described. These results show that COX, and COX-2 in particular, can play a substantial role in HCA activation, especially in extrahepatic tissues like the colon. Furthermore, the obvious interactions between PUFA and HCA in COX-2 expressing cancer cells may be important in modulating colorectal cancer risk.

Topics: Adenocarcinoma; Amines; Cell Survival; Colonic Neoplasms; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP1A2 Inhibitors; Dinoprostone; DNA Adducts; Enzyme Inhibitors; Fatty Acids, Unsaturated; Heterocyclic Compounds; Humans; Linoleic Acid; Prostaglandin-Endoperoxide Synthases; Tumor Cells, Cultured

Conjugated linoleic acid (CLA) has chemoprotective properties in experimental cancer models, and in vitro studies have shown that CLA inhibits HT-29 colon cancer cell growth. ErbB2 and ErbB3 have been implicated in the development of colon cancer, and both proteins are expressed at high levels in the HT-29 cell line. Activation of ErbB2/ErbB3 heterodimers is regulated by the ErbB3 ligand heregulin. To examine CLA regulation of HT-29 cell proliferation and apoptosis and the influence of CLA on the ErbB3 signaling pathway, HT-29 cells were cultured in the presence of CLA and/or heregulin. CLA inhibited DNA synthesis and induced apoptosis of HT-29 cells. Although the addition of heregulin-alpha led to an increase in cell number, it was not able to counteract the negative growth regulatory effect of CLA. Immunoprecipitation/Western blot studies revealed that CLA inhibited heregulin-alpha-stimulated phosphorylation of ErbB2 and ErbB3, recruitment of the p85 subunit of phosphoinositide 3-kinase (PI3-kinase) to the ErbB3 receptor, ErbB3-associated PI3-kinase activities, and phosphorylation of Akt. CLA decreased ErbB2 and ErbB3 mRNA and protein levels in a dose-dependent manner. In conclusion, we demonstrate that CLA inhibits cell proliferation and stimulates apoptosis in HT-29 cells and that this may be mediated by its ability to downregulate ErbB3 signaling and the PI3-kinase/Akt pathway.

Topics: Adenocarcinoma; Apoptosis; Cell Division; Colonic Neoplasms; Dose-Response Relationship, Drug; Gene Expression Regulation; Humans; Linoleic Acid; Neuregulin-1; Receptor, ErbB-3; Signal Transduction; Tumor Cells, Cultured

To study the effects of c9,t11-conjugated linoleic acid (c9,t11-CLA) on invasive ability of human gastric carcinoma cell line (SGC-7901) and to explore its possible mechanism.. Reconstituted basement membrane invasion assay was used to evaluate invasive ability of cancer cells. Expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA was measured by reverse transcription polymerase chain reaction (RT-PCR) in SGC-7901 cells.. At the concentrations of 200 micromol/L, 100 micromol/L and 50 micromol/L, c9,t11-CLA suppressed their reconstituted basement membrane invasion of SGC-7901 by 53.7%, 40.9% and 29.3%, respectively. c9,t11-CLA could induce the expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA in SGC-7901 cells.. The invasion of SGC-7901 cells could be inhibited by c9,t11-CLA through reconstituted basement membrane. Anti-invasion action of c9,t11-CLA might be associated with induction of expression of TIMP-1, TIMP-2 and nm23-H(1) mRNA in tumor cells.

Topics: Adenocarcinoma; Gene Expression; Humans; Linoleic Acid; Monomeric GTP-Binding Proteins; Neoplasm Invasiveness; NM23 Nucleoside Diphosphate Kinases; Nucleoside-Diphosphate Kinase; RNA, Messenger; Stomach Neoplasms; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2; Transcription Factors; Tumor Cells, Cultured

Conventional linoleic acid (LA) is regarded as a promotor of carcinogenesis. However, the effect of its conjugated derivative on cancer is still unknown. Therefore we investigated the influence of conventional and conjugated LA on tumor growth and lipid peroxidation in a solid model of pancreatic adenocarcinoma in Syrian hamsters. 60 male hamsters were randomized in 4 groups (Gr.) (n=15). Gr. 1 and 2 received 0.5 ml 0.9% sodium chloride subcutaneously (s.c.) once a week while Gr. 3 and 4 were injected 10 mg N-nitrosobis-2-oxopropylamine (BOP)/kg body weight weekly for 12 weeks to induce pancreatic cancer. Gr. 1 and 3 received a diet containing conventional LA, Gr. 2 and 4 were fed a diet of conjugated LA. After 29 weeks all animals were sacrificed, pancreas was weighed and examined macroscopically and histologically. The level of lipid peroxidation and activities of glutathion peroxidase and superoxide dismutase were determined in tumor-free as well as in pancreatic carcinoma tissue. Different diets did not influence the incidence of pancreatic carcinoma, however, pancreas weight was increased by conjugated LA compared to conventional LA. Furthermore both diets decreased the activity of glutathion peroxidase and increased the level of lipid peroxidation in pancreatic intratumoral tissue. The content of conjugated LA in dietary did not influence pancreatic tumor growth in a solid model of pancreatic adenocarcinoma in Syrian hamsters.

Topics: Adenocarcinoma; Animals; Cell Division; Cricetinae; Dietary Fats; Glutathione Peroxidase; Linoleic Acid; Linoleic Acids, Conjugated; Lipid Peroxidation; Male; Mesocricetus; Pancreas; Pancreatic Neoplasms; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

It is well known that simvastatin affects cholesterol synthesis. Furthermore it inhibits growth and proliferation and perturbs fatty acid metabolism in some cell lines. We have studied the effects of simvastatin on the uptake and metabolism of exogenous fatty acid in the human lung adenocarcinoma A549 cells. Simvastatin inhibited the proliferation of A549, and caused an increment in phospholipid/cholesterol ratio due to an increment in phospholipid content without affecting cholesterol content. All the fatty acids were uptaken and metabolized in both control and treated cells. The conversion of palmitic, linoleic and dihomo-gamma-linoleic acids to their metabolites and products/precursor ratios for the desaturation and elongation reactions showed that simvastatin enhanced the Delta5 desaturation step and altered some elongating steps. The machinery for unsaturated fatty acid synthesis in A549 is quite sensitive to simvastatin and its effects could have important implication taking into account that highly unsaturated fatty acids are involved in the regulation of diverse cellular functions by themselves or through their metabolites.

Topics: Adenocarcinoma; alpha-Linolenic Acid; Anticholesteremic Agents; Cell Line; Cholesterol; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Linoleic Acid; Lung Neoplasms; Palmitic Acid; Phospholipids; Simvastatin

Topics: Adenocarcinoma; Arachidonate 15-Lipoxygenase; Arachidonic Acid; Base Sequence; Chromatography, High Pressure Liquid; DNA Primers; Humans; Linoleic Acid; Male; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription, Genetic; Tumor Cells, Cultured

We have investigated the effects of various fatty acids (FAs) on integrin-mediated MDA-MB-435 breast carcinoma cell adhesion to type IV collagen (collagen IV) in vitro. Arachidonic acid (AA) and linoleic acid both induced a dose-dependent increase in cell adhesion to collagen IV with no significant increase in nonspecific adhesion to polylysine and BSA. Oleic acid (a monounsaturated FA), AA methyl ester, and linoelaidic acid (a trans-isomer of linoleic acid) failed to stimulate adhesion to collagen IV, suggesting that these effects required cis-polyunsaturation and a free carboxylic moiety and that they were not due to membrane perturbations. Calphostin C, a protein kinase C (PKC) inhibitor, blocked cis-polyunsaturated FA (cis-PUFA)-induced cell adhesion in a dose-dependent manner, suggesting a role for a calcium-dependent PKC in this signal transduction pathway. Immunoblotting revealed that cis-PUFAs induced the translocation of PKCepsilon and PKCmu, two of the novel PKC isozymes, from the cytosol to the membrane. In contrast, a conventional PKC isozyme, PKCalpha, as well as the atypical isozymes, PKCzeta and PKCiota, did not translocate after cis-PUFA treatment. Function-blocking antibodies specific for alpha1, alpha2, and beta1, integrin subunits inhibited cell adhesion to collagen IV, whereas antibodies to alpha3 and alpha5 did not. No increase in the expression of these integrins on the cell surface was detected after the incubation of cells with cis-PUFAs, suggesting that there is an increase in the activity, but not in the amount, of these beta1, integrins. Altogether, these data suggest that cis-PUFAs enhance human breast cancer cell adhesion to collagen IV by selectively activating specific PKC isozymes, which leads to the activation of beta1 integrins.

Topics: Adenocarcinoma; Arachidonic Acid; Breast Neoplasms; Cell Adhesion; Collagen; Dietary Fats, Unsaturated; Enzyme Activation; Fatty Acids, Unsaturated; Flow Cytometry; Humans; Immunoblotting; Integrin beta1; Isoenzymes; Linoleic Acid; Oleic Acid; Protein Kinase C; Protein Kinase C-epsilon; Stimulation, Chemical; Substrate Specificity; Tumor Cells, Cultured

The effect of overexpression of 15-lipoxygenase-1 (15-LO-1) was studied in the human prostate cancer cell line, PC-3. Stable PC-3 cell lines were generated by transfection with 15-LO-1-sense (15-LOS), 15-LO-1-antisense (15-LOAS) or vector (Zeo) and selection with Zeocin. After characterization by RT-PCR, western and HPLC, a PC3-15LOS clone was selected that possessed 10-fold 15-LO-1 enzyme activity compared with parental PC-3 cells. The PC3-15LOAS clone displayed little or no 15-LO-1 activity. These PC-3 cell lines were characterized for properties of tumorigenesis. The proliferation rates of the cell lines were as follows: PC3-15LOS > PC-3 = PC3-Zeo > PC3-15LOAS. Addition of a specific 15-LO-1 inhibitor, PD146176, caused a dose-dependent inhibition of proliferation in vitro. Overexpression of 15-LO-1 also caused [(3)H]thymidine incorporation to increase by 4.0-fold (P < 0.01). Compared with parental and PC-3-Zeo cells, PC3-15LOS enhanced whereas PC3-15LOAS reduced the ability of PC-3 cells to grow in an anchorage-independent manner, as assessed by colony formation in soft agar. These data suggested a pro-tumorigenic role for 15-LO-1 in PC-3 cells in vitro. Therefore, to clarify the role of 15-LO-1 in vivo, the effect of 15-LO-1 expression on the growth of tumors in nude mice was investigated. The PC-3 cell lines were inoculated subcutaneously into athymic nude mice. The frequency of tumor formation was increased and the sizes of the tumors formed were much larger in the PC3-15LOS compared with PC3-15LOAS, parental PC-3 and PC-3-Zeo cells. Immunohistochemistry for 15-LO-1 confirmed expression throughout the duration of the experiment. The expression of factor VIII, an angiogenesis marker, in tumor sections was increased in tumors derived from PC3-15LOS cells and decreased in those from PC3-15LOAS cells compared with tumors from parental or Zeo cells. These data further supported the evaluation by ELISA of vascular endothelial growth factor (VEGF) secretion by PC-3 cells in culture. Secretion of this angiogenic factor was elevated in PC3-15LOS cells compared with the other cell lines. These results support a role for 15-LO-1 in a novel growth-promoting pathway in the prostate.

Topics: Adenocarcinoma; Animals; Arachidonate 15-Lipoxygenase; Blotting, Western; Cell Division; Chromatography, High Pressure Liquid; Colony-Forming Units Assay; Electrophoresis, Polyacrylamide Gel; Endothelial Growth Factors; Enzyme Induction; Factor VIII; Humans; Immunoenzyme Techniques; Linoleic Acid; Linoleic Acids; Lymphokines; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transfection; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Some fatty acids are reported to inhibit tumor growth of pancreatic carcinoma. However, it is still unknown if alpha-linolenic acid (ALA) and linoleic acid (LA) inhibit liver metastasis of ductal pancreatic adenocarcinoma. Therefore we studied the effect of these fatty acids on liver metastasis in the animal model of N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic adenocarcinoma in Syrian hamsters. Since lipid peroxidation seems to be involved in carcinogenesis and metastasis, we further analyzed the intrahepatic concentration of thiobarbituric acid-reactive substances (TBARS) and activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). We observed an increase in the incidence and the number of liver metastases in response to the combination of ALA and LA. This was accompanied by a decrease in hepatic GSH-Px activity and an increase in hepatic SOD activity and TBARS concentration. The increase in hepatic lipid peroxidation seems to be one possible mechanism of increasing liver metastasis in this study.

Topics: Adenocarcinoma; alpha-Linolenic Acid; Animals; Cricetinae; Dietary Fats, Unsaturated; Glutathione Peroxidase; Linoleic Acid; Lipid Peroxidation; Liver; Liver Neoplasms; Male; Mesocricetus; Nitrosamines; Pancreas; Pancreatic Neoplasms; Random Allocation; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

The aim of this study was to analyze possible changes in the total phospholipid distribution in murine mammary adenocarcinomas induced in transgenic mice by the tissue-specific expression of the neu oncogene, as compared with normal tissues. To understand whether the altered phospholipid profile might be specifically tissue-related to the oncogene expression, phospholipid composition also has been analyzed in liver, kidney, lung, and spleen. The data indicate that only tumor mammary tissues show a drastic increase of the total phospholipid content (P < 0.0001) associated with a significant increment of phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin (P < 0.05). Moreover, gas-chromatography analysis of total phospholipid-derived fatty acids shows a decrease in the percentage content of linoleic acid in tumor tissues, suggesting an altered metabolism of this fatty acid related to the enhanced epithelial proliferation. We conclude that neu transgenic mice provide a good model to clarify the involvement of phospholipids in neu-induced neoplastic transformation and to study in vivo the metabolic pathways related to the intracellular signaling.

Topics: Adenocarcinoma; Animals; Cell Division; Chromatography, Gas; Fatty Acids; Female; Kidney; Linoleic Acid; Liver; Lung; Male; Mammary Neoplasms, Animal; Mice; Mice, Transgenic; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Receptor, ErbB-2; Signal Transduction; Sphingomyelins; Spleen

We recently reported that the mutant form of the tumor-suppressor gene p53 up-regulates 15-LO-1 gene expression in a murine cell line. Here, we examine the expression of 15-lipoxygenase (LO)-1 and mutant p53 (mtp53) in human prostatic tissues and 15-LO-1 in the human prostate adenocarcinoma cell line PC-3. Reverse transcription-PCR and western analyses conclusively demonstrated expression of 15-LO-1 in PC-3 cells. Western blotting for 15-LO-1 in freshly resected 'normal' and prostate adenocarcinoma specimens showed 15-LO-1 expression in normal tissue, but significantly higher levels were detected in prostate adenocarcinomas. Prostate adenocarcinoma tissues generated chirally pure 13-S-hydroxyoctadecadienoic acid from exogenous linoleic acid, a preferred substrate of 15-LO-1. To study the correlation of 15-LO-1 expression with mtp53 in prostate cancer, we immunostained 48 prostatectomy specimens obtained by transurethral resection of the prostate and needle biopsy (median age 68 years, range 52-93) of different Gleason grades (n = 48), using antibodies specific for 15-LO-1, mtp53 and MIB-1 (a proliferation marker). We compared staining in cancerous foci with adjacent normal appearing prostate tissues. In only 5 of 48 patients did 'normal' tissue adjacent to cancerous foci display staining for 15-LO-1. However, no staining for mtp53 was observed in any of the normal tissues. In cancer foci, robust staining was observed for both 15-LO-1 (36 of 48, 75%) and mtp53 (19 of 48, 39%). Furthermore, the intensities of expression of 15-LO-1 and mtp53 correlated positively with each other (P < 0.001) and with the degree of malignancy, as assessed by Gleason grading (P < 0.01). By immunohistochemistry, 15-LO-1 was located in secretory cells of peripheral zone glands, prostatic ducts and seminal vesicles, but not in the basal cell layer or stroma. Based on these and other studies, we propose a model describing a possible role for 15-LO-1 expression in influencing the malignant potential and pathobiological behavior of adenocarcinomas.

Topics: Adenocarcinoma; Arachidonate 15-Lipoxygenase; Arachidonic Acid; Blotting, Western; Enzyme Induction; Humans; Immunohistochemistry; Linoleic Acid; Linoleic Acids; Male; Mutation; Neoplasm Staging; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; Stereoisomerism; Tumor Cells, Cultured; Tumor Suppressor Protein p53

2,3,5-Trimethyl-6-(3-pyridylmethyl)1,4-benzoquinone (CV-6504), an inhibitor of 5-lipoxygenase and thromboxane A2 synthase and a scavenger of active oxygen species, has been shown to exhibit profound anti-tumour activity against three established murine adenocarcinomas (MACs) that are generally refractory to standard cytotoxic agents. For the cachexia-inducing MAC16 tumour, optimal anti-tumour activity was seen at dose levels of 10 and 25 mg kg-1 day-1, together with a reversal of cachexia and a doubling of the time to sacrifice of the animals through cachexia from 8 days to 17 days. The remaining tumour fragments showed extensive necrosis in regions distal from the blood supply. Growth of the MAC13 tumour was also effectively suppressed at dose levels between 5 and 50 mg kg-1 day-1, resulting in a specific growth delay between 1.0 and 1.2. Growth of the MAC26 tumour was also inhibited a concentration-related manner, with doses of 25-50 mg kg-1 day-1 being optimal. Anti-tumour activity towards all three tumours at low dose levels of CV-6504 was effectively suppressed by concurrent administration of linoleic acid (1 g kg-1 day-1), suggesting that inhibition of linoleate metabolism was responsible for the anti-tumour effect. Tumour sensitivity may be correlated with increased DT-diaphorase that are required to metabolise CV-6504 to the active hydroquinone, which inhibits 5-lipoxygenase activity.

Topics: Adenocarcinoma; Administration, Oral; Animals; Antineoplastic Agents; Benzoquinones; Cell Division; Colonic Neoplasms; Growth Inhibitors; Linoleic Acid; Linoleic Acids; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred Strains

The effect of the polyunsaturated fatty acids (PUFAs) linoleic acid (LA) and arachidonic acid (AA) on the growth of two murine colon adenocarcinoma cell lines (MAC26 and MAC13) has been determined both in vitro and in vivo. When the serum concentrations in the medium became growth limiting, low concentrations (18-33 microM) of both PUFAs were growth stimulatory to both cell lines, while higher concentrations were growth inhibitory. Growth stimulation by AA in both cell lines, and by LA in MAC13, was effectively inhibited by both the cyclo-oxygenase and lipoxygenase inhibitor indomethacin, and the lipoxygenase inhibitor BWA4C in a dose-dependent manner. The most effective inhibition was exerted by BWA4C, suggesting metabolism of both PUFAs through the lipoxygenase pathway for growth stimulation. In vivo studies using the MAC26 tumour showed a significant stimulation of tumour growth when LA was administered orally at concentrations higher than 0.4 g kg-1 day-1. Higher concentrations did not produce a further increase in tumour growth rate. This suggests that there is a threshold dose for growth stimulation by LA which, together with that in the diet, amounted to 3.8% of the total caloric intake. The increase in tumour volume induced by LA arose from a reduction in the potential doubling time from 41 to 28 h and was effectively reversed by indomethacin (5 mg kg-1). These results suggest that PUFAs may play an important role in tumour growth and may offer a potential target for the development of chemotherapeutic agents.

Topics: Adenocarcinoma; Analysis of Variance; Animals; Arachidonic Acid; Benzeneacetamides; Cell Division; Colonic Neoplasms; Cyclooxygenase Inhibitors; Dietary Fats, Unsaturated; Dose-Response Relationship, Drug; Hydroxamic Acids; Indomethacin; Linoleic Acid; Linoleic Acids; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred Strains; Tumor Cells, Cultured

Oral administration of eicosapentaenoic acid (EPA) (2.0 g/kg) by gavage to female NMRI mice bearing the MAC16 colon adenocarcinoma and with weight loss, prevented further loss in body weight and produced a delay in the growth of the tumour. Cell production and loss were determined by the [125I]5-iodo-2'-deoxyuridine method during the stationary and growth phase of the tumour in animals treated with EPA. Tumour stasis appeared to arise from an increase in the rate of cell loss from 38 to 71% without a significant change in the potential doubling time. During the subsequent growth phase the cell loss factor was reduced to 52% and this was combined with a reduced potential doubling time from 32 to 26 hr. The antiproliferative, but not the anticachectic effect of EPA could be reversed by oral administration of pure linoleic acid (LA), (1.9 g/kg) which acted to increase tumour growth by reducing the cell loss factor to 45%. Despite this reversal, incorporation of EPA into tumour cell lipids was not significantly different in animals administered with either EPA alone or combined with LA. This suggests that the antiproliferative effect of EPA in this system may arise from an indirect effect through the blocking of the catabolic effect of the tumour on host adipose tissue, which normally supplies fatty acids essential for tumour growth. This suggests that LA may be required by some tumours to prevent cell loss and that the catabolism of adipose tissue, which accompanies cancer cachexia effectively supplies this fatty acid to the tumour.

Topics: Adenocarcinoma; Animals; Body Weight; Cell Cycle; Colonic Neoplasms; Eicosapentaenoic Acid; Fatty Acids; Female; Linoleic Acid; Linoleic Acids; Lipids; Mice; Tumor Cells, Cultured

The growth-promoting effect of several hormones and growth factors on eight human colon tumor cell lines (SW 48, SW 403, SW 480, SW 620, SW 948, HT29, LS174T and Caco-2) was studied using seven different chemically defined serum-free media [GF3: Chee's essential medium plus insulin, transferrin and selenium; GF3F: GF3 plus fetuin; GF4: GF3 plus linoleic acid/bovine-serum albumin (BSA); GF5: GF4 plus fetuin, GF5E, GF5 plus EGF; GF5T: GF5 plus triiodothyronine; GF7: GF3 plus EGF, transferrin, insulin, linoleic acid/BSA, oleic acid/BSA and fetuin]. GF5 appears to be the best serum-free medium as it supported continuous growth of all of the colon tumor cell lines. GF5 also supported growth of five of the seven human colon and stomach tumor xenografts as primary tissue cultures. However, the stomach xenograft cells had a very slow growth rate as compared to the colon xenograft cells in the medium. Cells grown in GF5 retained their tumorigenicity in athymic (nude) mice and characteristic cellular morphology. GF7 was the poorest of all of the serum-free media studied as none of the cell lines or xenografts grew in this medium.

Topics: Adenocarcinoma; alpha-Fetoproteins; Cell Division; Cell Line; Colonic Neoplasms; Culture Media, Serum-Free; Culture Techniques; Epidermal Growth Factor; Humans; Insulin; Linoleic Acid; Linoleic Acids; Neoplasm Transplantation; Oleic Acid; Oleic Acids; Transferrin; Triiodothyronine; Tumor Cells, Cultured

Interpretation of studies comparing the efficacy of different dietary fat sources in promoting 7,12-dimethylbenz[a]-anthracene (DMBA)-induced rat mammary tumorigenesis often ignores the fact that about 4% (wt/wt) linoleic acid (18:2n-6) is required for optimal tumor promotion. We therefore fed DMBA-intubated or placebo-intubated female, Sprague-Dawley rats 20% fat diets containing 18:2n-6 (wt/wt) from either high-linoleic safflower oil (SL, 14.6% 18:2n-6), high-oleic safflower oil (SO, 3.4% 18:2n-6), olive oil (OO, 1.1% 18:2n-6), or OO supplemented with 18:2n-6 (OL, 3.4% 18:2n-6) for 16 weeks. Results indicated that OO-fed rats had longer tumor-free time, fewer tumors per rat, and lower tumor incidence compared with SO and OL. Addition of 2.3% 18:2n-6 to OO enhanced tumor promotion (p less than 0.04); SL, SO, and OL demonstrated similar tumor-enhancement effect. About 74% of observed mammary tumors were adenocarcinomas; a greater number of tumors appeared in the thoracic and inguinal than in the cervical and abdominal regions irrespective of diet. These results indicate that once an optimal amount of linoleic acid is provided in the diet, oleic- or linoleic-rich oils have similar effects on promotion of mammary tumors in the rat.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adenocarcinoma; Animals; Body Weight; Carcinogens; Dietary Fats, Unsaturated; Female; Insulin-Like Growth Factor I; Linoleic Acid; Linoleic Acids; Liver; Mammary Neoplasms, Experimental; Olive Oil; Organ Size; Plant Oils; Rats; Rats, Inbred Strains; Safflower Oil; Spleen

A reduction in the size of transplantable mammary adenocarcinoma IX was achieved when female BALB/c mice were fed isocaloric 10% fat diets containing either hydrogenated cottonseed oil (HCTO) or menhaden oil (MO) as opposed to those mice fed corn oil (CO). Indeed, CO increased the size of the neoplasms when fed alone at 5 or 1% of the diet, although such diets contained less fat calories than did the 10% fat diets containing the other two oils. At the 10% level of dietary fat, enhanced accumulation of tumor mass was observed even when 7.5, 5.0, and 2.5% CO was administered in combination with either HCTO or MO. Although this effect of CO could not be inhibited when nine times as much HCTO was added to the diet, such growth enhancement was abolished when the diet contained nine times as much MO. Hence these experiments emphasized the importance of the type rather than the amount of dietary fat. Whereas MO contained polyunsaturated fatty acids (PUFA's) [approximately 1% as linoleic acid, approximately 16% as 5,8,11,14,17-eicosapentaenoic acid (EPA), approximately 11% as 4,7,10,13,16,19-docosahexaenoic acid (DHA)], HCTO contained none and CO had about 60% of its constituent fatty acids in the form of linoleic acid. The rate of tumor cell loss, determined by the [125I]5-iodo-2'-deoxyuridine method, in the 10% MO-fed or the 10% HCTO-fed mice (54 or 45%, respectively) was more than twice that observed for tumors from the 10% CO-fed mice (22%). These observations were discussed in terms of the influence of the dietary PUFA linoleic acid [C 18:2 (No. of carbons:No. of double bonds), n-6], the PUFA EPA (C 20:5, n-3), and the PUFA DHA (C 22:6, n-3) on the size of mammary tumors and on the involvement of prostaglandins in this process.

Topics: Adenocarcinoma; Animals; Body Weight; Corn Oil; Cottonseed Oil; Dietary Fats; Fatty Acids; Female; Fish Oils; Linoleic Acid; Linoleic Acids; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Oils; Prostaglandins

Topics: Adenocarcinoma; Adipose Tissue; Adult; Animals; Female; Humans; Leukemia, Experimental; Linoleic Acid; Linoleic Acids; Lipid Mobilization; Male; Mice; Mice, Inbred AKR; Middle Aged; Peptides