13-hydroxy-9-11-octadecadienoic-acid and Adenocarcinoma

In previous studies, we have found that expression of 15-lipoxygenase-1 (15-LOX-1) and its main product, 13-S-hydroxyoctadecadienoic acid, are decreased in human colorectal cancers and that nonsteroidal anti-inflammatory drugs (NSAIDs) can therapeutically induce 15-LOX-1 expression to trigger apoptosis in human colorectal cancer cells. NSAIDs similarly induce apoptosis in esophageal cancer cells, although the mechanisms of these effects remain to be defined. In the present study, we tested whether 15-LOX-1 is down-regulated in human esophageal cancers using paired normal and tumor human surgical samples and whether NSAIDs can up-regulate 15-LOX-1 to restore apoptosis in esophageal cancer cells. We found that: (a) 15-LOX-1 was down-regulated in human esophageal carcinomas; (b) NSAIDs induced 15-LOX-1 expression during apoptosis in esophageal cancer cells; and (c) 15-LOX-1 inhibition suppressed NSAID-induced apoptosis, which was restored by 13-S-hydroxyoctadecadienoic acid but not by its parent compound, linoleic acid. These findings demonstrate that 15-LOX-1 is down-regulated in human esophageal carcinomas and that NSAIDs induce apoptosis in esophageal cancer cells via up-regulation of 15-LOX-1. They also support the concept that the loss of the proapoptotic role of 15-LOX-1 in epithelial cancers is not limited to human colorectal cancers.

Topics: Adenocarcinoma; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Arachidonate 15-Lipoxygenase; Carcinoma, Squamous Cell; Enzyme Induction; Esophageal Neoplasms; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Linoleic Acids; Nitrobenzenes; Sulfonamides; Sulindac; Up-Regulation

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

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

Recent studies have identified a role for the oxidation product of linoleic acid, 13-hydroxyoctadecadienoic acid (13-HODE) in cell proliferation. The enzyme 13-HODE dehydrogenase catalyzes the conversion of 13-HODE to 13-oxooctadecadienoic acid. This enzyme has been shown to correlate with the degree of differentiation of intestinal cells in both in vitro and in vivo models. Higher enzyme levels are found in more differentiated cell types. The present study was done to determine if enzyme levels of 13-HODE dehydrogenase are predictive of the differentiation status of biopsies from human colonic mucosa. Twenty-eight patients who underwent diagnostic colonoscopy (10 patients with adenocarcinoma and 18 with adenomatous polyps) had biopsies taken from both normal rectal mucosa and neoplastic mucosa. The determination of 13-HODE dehydrogenase activity was conducted by high-performance liquid chromatography analysis of all biopsy samples. Sixteen of the 18 patients with polyps had lower 13-HODE dehydrogenase activity in the adenoma than in the uninvolved rectal mucosa (P = 0.001). The colon adenocarcinomas also had less 13-HODE dehydrogenase activity in the cancer biopsy tissue than in uninvolved rectal mucosa (P = 0.041) These data are consistent with a role for 13-HODE dehydrogenase in intestinal cell differentiation. Understanding the precise role of this enzymatic reaction could be important potentially in the therapy and biology of colon cancer. In addition, measurements of 13-HODE dehydrogenase may be a useful parameter by which to ascertain the differentiation status of intestinal cells in vitro.

Topics: Adenocarcinoma; Adenomatous Polyps; Adult; Aged; Biomarkers, Tumor; Biopsy; Colonoscopy; Colorectal Neoplasms; Humans; Intestinal Mucosa; Linoleic Acids; Middle Aged; Oxidoreductases; Sensitivity and Specificity