13-hydroxy-9-11-octadecadienoic-acid and Colonic-Neoplasms

The relationship between 15(S)-HETE and 13(S)-HODE from different human tumor cells exposed to n-6 and n-3 essential fatty acids (EFAs) and E-cadherin expression was studied. Colon cancer cells (HRT-18) exposed to gamma linoleic acid (18:3n-6, GLA) and eicosapentaenoic (20:5n-3, EPA) (50microM) showed an increased expression of E-cadherin. Breast cancer (MCF-7) exposed to EPA showed an increment whereas GLA had no effect on E-cadherin expression. No expression of E-cadherin was observed for urothelial cancer (T-24) after GLA or EPA treatment. Significant levels of 15(S)-HETE and 13(S)-HODE were detected after GLA or EPA treatment for all tumor lines. E-cadherin expression was inversely proportional to the 13(S)-HODE:15(S)-HETE ratio when cells were pretreated with GLA or EPA. Nevertheless, the liberation of these metabolites seems to be independent of the E-cadherin expression. The increase in the13(S)-HODE:15(S)-HETE correlates to a decrease in the expression of E-cadherin. Both factors may play a role in metastasis development.

Topics: Arachidonic Acid; Breast Neoplasms; Cadherins; Cell Differentiation; Colonic Neoplasms; Female; Humans; Hydroxyeicosatetraenoic Acids; Immunohistochemistry; Linoleic Acid; Linoleic Acids; Neoplasm Metastasis; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Urothelium

Human colon tumors have elevated levels of 15-lipoxygenase-1 (15-LO-1), suggesting that 15-LO-1 may play a role in the development of colorectal cancer. Also, 15-LO-1 metabolites can up-regulate epidermal growth factor signaling pathways, which results in an increase in mitogenesis. However, metabolites of 15-LO-1 can serve as ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), and activation of this receptor causes most colon cancer cell lines to undergo a differentiative response and reverse their malignant phenotype. Hence, the role 15-LO-1 plays in colon cancer is not clear. To clarify the role of 15-LO-1 in carcinogenesis, the effect of 15-LO-1 and its metabolites on epidermal growth factor signaling and PPARgamma was investigated. In HCT-116 cells, exogenously added 15-LO-1 metabolites, 13-(S)-hydroxyoctadecadienoic acid, 13-(R)-hydroxyoctadecadienoic acid, and 13-(S)-hydroperoxyoctadecadienoic acid, up-regulated the MAPK signaling pathway, and an increase in PPARgamma phosphorylation was observed. Furthermore, in stable overexpressing 15-LO-1 HCT-116 cells, which produce endogenous 15-LO-1 metabolites, an up-regulation in mitogen-activated protein kinase and PPARgamma phosphorylation was observed. Incubation with a MAPK inhibitor ablated MAPK and PPARgamma phosphorylation. The 15-LO-1 up-regulates MAPK activity and increases PPARgamma phosphorylation, resulting in a down-regulation of PPARgamma activity. Thus, 15-LO-1 metabolites may not only serve as ligands for PPARgamma but can down-regulate PPARgamma activity via the MAPK signaling pathway.

Topics: Arachidonate 15-Lipoxygenase; Colonic Neoplasms; Dose-Response Relationship, Drug; Down-Regulation; Humans; Isoenzymes; Linoleic Acids; MAP Kinase Signaling System; Phosphorylation; Receptors, Cytoplasmic and Nuclear; Transcription Factors; Tumor Cells, Cultured

We previously found (I. Shureiqi et al., Carcinogenesis (Lond.), 20: 1985-1995, 1999; I. Shureiqi et al, J. Natl. Cancer Inst., 92: 1136-1142, 2000) that (a) 15-lipoxygenase-1 (15-LOX-1) protein and its product 13-S-hydroxyoctadecadienoic acid (13-S-HODE) are decreased; and (b) nonsteroidal anti-inflammatory drug (NSAID)-induced 15-LOX-1 expression is critical to NSAID-induced apoptosis in colorectal cancer cells expressing cyclooxygenase-2 (COX-2). We used the NSAIDs sulindac sulfone (COX-2-independent) and NS-398 (a COX-2 inhibitor) to assess NSAID upregulation of 15-LOX-1 in relation to COX-2 inhibition during NSAID-induced apoptosis in the DLD-1 (COX-2-negative) colon cancer cell line. We found that: (a) NSAIDs up-regulated 15-LOX-1, which preceded apoptosis; and (b) 15-LOX-1 inhibition blocked NSAID-induced apoptosis, which was restored by 13-S-HODE but not by its parent, linoleic acid. NSAIDs can induce apoptosis in colon cancer cells via up-regulation of 15-LOX-1 in the absence of COX-2.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antineoplastic Agents; Antioxidants; Antithrombins; Apoptosis; Arachidonate 15-Lipoxygenase; Arachidonic Acid; Blotting, Western; Caffeic Acids; Cell Line; Colonic Neoplasms; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Humans; Hydroxyeicosatetraenoic Acids; Isoenzymes; Linoleic Acid; Linoleic Acids; Membrane Proteins; Nitrobenzenes; Prostaglandin-Endoperoxide Synthases; Recombinant Proteins; Sulfonamides; Sulindac; Time Factors; Tumor Cells, Cultured; Up-Regulation

13-S-Hydroxyoctadecadienoic acid (13-S-HODE), the product of 15-lipoxygenase (15-LOX) metabolism of linoleic acid, enhances cellular mitogenic responses to certain growth factors. Other observations have questioned whether 13-S-HODE has tumorigenic effects. Our study evaluated the hypothesis that 15-LOX-1 is overexpressed in colon cancers resulting in an increase in intracellular 13-S-HODE. 15-LOX-1 and 13-S-HODE were quantified using western blots, ELISA and immunohistochemistry in 18 human colon cancers with paired normal colonic mucosa. Additionally, 15-LOX-1 expression was measured by western blots in three transformed colonic cell lines and in a human umbilical vein endothelial cell line. Next, we evaluated 13-S-HODE effects on cellular proliferation, cell cycle distribution and apoptosis in a transformed colonic cell line (RKO). Cell cycle distributions were measured by flow cytometry and apoptosis was assessed by phase contrast microscopy, electron microscopy, flow cytometry and DNA fragmentation assay. 15-LOX-1 immunohistochemistry staining scores were reduced in tumor tissues (P

Topics: Apoptosis; Arachidonate 15-Lipoxygenase; Blotting, Western; Cell Cycle; Cell Division; Colonic Neoplasms; Enzyme-Linked Immunosorbent Assay; Humans; Immunohistochemistry; Linoleic Acids; Tumor Cells, Cultured

The arachidonate 15-lipoxygenase is induced in peripheral human monocytes by culturing the cells for 3 days in the presence of interleukin 4 (IL-4) in concentrations as low as 40 pM. Linoleic acid is oxygenated by IL-4 treated monocytes to 13(S)-hydroxy-9Z, 11E-octadecadienoic acid [13(S)-HODE] with a specific activity of about 2 nmoles 13(S)-HODE/10(6) cells min. A screening of various permanent cell lines expressing the IL-4 receptor indicated that all monocyte/macrophage lines tested did not exhibit the effect of LOX induction. However, IL-4 treatment of the lung carcinoma cell line CCC 185 and of the colon carcinoma cell line HTB 38 induces the 15-LOX as shown by activity assay and immunohistochemistry. The IL-4 mutant Y124D which has been characterized as specific IL-4 receptor antagonist in human T-cells does not induce the 15-LOX but appears to act as competitive inhibitor for the induction. Subcellular fractionation of IL-4 treated monocytes indicated a cytosolic and a membrane bound enzyme pool. The intracellular action of the LOX leads to a specific oxygenation of the membrane phospholipids which is drastically increased after damage to the cells. The possible biological role of the 15-LOX for monocyte metabolism is discussed.

Topics: Arachidonate 15-Lipoxygenase; Cells, Cultured; Colonic Neoplasms; Cytokines; Enzyme Induction; HL-60 Cells; Humans; Interleukin-4; Linoleic Acids; Lung Neoplasms; Lymphocytes; Monocytes; Point Mutation; T-Lymphocytes; Tumor Cells, Cultured