methyl-jasmonate and Prostatic-Neoplasms

Broccoli is rich in bioactive components, such as sulforaphane and indole-3-carbinol, which may impact cancer risk. The glucosinolate profile of broccoli can be manipulated through treatment with the plant stress hormone methyl jasmonate (MeJA). Our objective was to produce broccoli with enhanced levels of indole glucosinolates and determine its impact on prostate carcinogenesis. Brassica oleracea var. Green Magic was treated with a 250 μM MeJA solution 4 days prior to harvest. MeJA-treated broccoli had significantly increased levels of glucobrassicin, neoglucobrassicin, and gluconasturtiin (P < .05). Male transgenic adenocarcinoma of mouse prostate (TRAMP) mice (n = 99) were randomized into three diet groups at 5-7 weeks of age: AIN-93G control, 10% standard broccoli powder, or 10% MeJA broccoli powder. Diets were fed throughout the study until termination at 20 weeks of age. Hepatic CYP1A was induced with MeJA broccoli powder feeding, indicating biological activity of the indole glucosinolates. Following ∼ 15 weeks on diets, neither of the broccoli treatments significantly altered genitourinary tract weight, pathologic score, or metastasis incidence, indicating that broccoli powder at 10% of the diet was ineffective at reducing prostate carcinogenesis in the TRAMP model. Whereas broccoli powder feeding had no effect in this model of prostate cancer, our work demonstrates the feasibility of employing plant stress hormones exogenously to stimulate changes in phytochemical profiles, an approach that may be useful for optimizing bioactive component patterns in foods for chronic-disease-prevention studies.

Topics: Acetates; Animals; Brassica; Carcinogenesis; Cyclopentanes; Glucosinolates; Indoles; Male; Mice, Inbred C57BL; Oxylipins; Plant Extracts; Plant Growth Regulators; Prostatic Neoplasms

Although the anti-cancer agent methyl jasmonate (MJ) has been shown to selectively target malignant cells while sparing normal ones, hormone-refractory prostate cancer cells are relatively resistant to MJ than other cancer cells. In the present study, we investigated the effect of cell permeable seven-residue peptide of Smac (SmacN7), an antagonist of the inhibitor of apoptosis proteins (IAPs), on MJ-induced apoptosis. SmacN7 significantly enhanced the growth inhibition effect of MJ in human prostate cancer cells, but not in proximal tubular epithelial cells. Moreover, SmacN7 sensitizes MJ-induced apoptosis through both caspase-9-dependent and -independent pathways. Thus, blockade of the over-expressed IAPs in cancer cells could yield a potential therapeutic benefit in jasmonates-based chemotherapy.

Topics: Acetates; Amino Acid Sequence; Apoptosis; Blotting, Western; Caspase 3; Caspase 9; Cell Line; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclopentanes; Dose-Response Relationship, Drug; Down-Regulation; Drug Synergism; Humans; Inhibitor of Apoptosis Proteins; Male; Oligopeptides; Oxylipins; Prostatic Neoplasms; Signal Transduction; X-Linked Inhibitor of Apoptosis Protein

Hormone refractory human prostate cancer cell lines are known to be radioresistant, a feature attributed to their ability to induce anti-apoptotic proteins of the Bcl-2 family when exposed to radiation. We investigated whether pro-apoptotic compounds such as methyl jasmonate, a plant stress hormone, can counteract the radiation-induced anti-apoptotic mechanism in a human prostate cancer cell line PC-3. Significant (p<0.05) increase in cytotoxicity was observed in the combined treatment groups compared to single treatments with methyl jasmonate or gamma-radiation. Treatment of irradiated PC-3 cells with methyl jasmonate resulted in suppression of anti-apoptotic Bcl-2 protein and elevation of caspase-3 activity. Our results showed increased apoptosis in the combined treatment group as compared to the irradiated group or the untreated control. In summary, methyl jasmonate suppressed the radiation-induced Bcl-2 expression and enhanced the radiation sensitivity of human prostate cancer cells.

Topics: Acetates; Adenocarcinoma; Annexin A5; Apoptosis; Caspase 3; Cell Death; Cell Line, Tumor; Cell Proliferation; Cyclopentanes; Dose-Response Relationship, Drug; Down-Regulation; Gamma Rays; Humans; Male; Oxylipins; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Radiation Tolerance; Radiation-Sensitizing Agents

Advanced prostate cancer cells are typically hormone independent, resistant to apoptosis and do not respond to chemotherapeutic agents. The ability of methyl jasmonate (MJ) and cis-jasmone (CJ) to inhibit growth in hormone independent prostate cancer cell lines, PC-3 and DU-145, was evaluated. CJ and MJ inhibited cell growth, induced cell cycle arrest and apoptosis. Detailed studies with the PC-3 cell line revealed that 2 mM CJ or MJ treatment resulted in caspase 3 activation and Tumor Necrosis Factor Receptor 1 (TNFR1) activation, all hallmarks of apoptosis. These phytochemicals could be useful in the management of advanced prostate cancer.

Topics: Acetates; Antineoplastic Agents, Phytogenic; Apoptosis; Caspase 3; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclopentanes; Humans; Male; Oxylipins; Prostatic Neoplasms; Receptors, Tumor Necrosis Factor, Type I

Methyl jasmonate--a plant stress hormone with striking resemblance to lipoxygenase products have been reported to induce apoptosis in several cancers. However, 5-HETE--a product of the lipoxygenase pathway has been implicated in human prostate cancer progression and yet possible interaction between methyl jasmonate and the lipoxygenase pathway has not been reported, thus, leaving some unanswered questions on the mechanism(s) of action by methyl jasmonate. Using cytotoxicity and flow cytometry assays (BrdU assay) as well as fluorescence microscopy, we investigated the effects of the methyl jasmonate on the proliferation of human prostate adenocarcinoma cell lines (DU-145, PC-3) in vitro and the potential interaction between methyl jasmonate and the lipoxygenase pathway. Methyl jasmonate (MJ) significantly (p = 0.01) inhibited the proliferation of human prostate carcinoma cells in dose- and kinetic-dependent manners and showed specific interaction with 5-lipoxygenase (5-LOX) enzyme pathway. Flow cytometric analyses and fluorescence microscopy confirmed that the inhibition of proliferation was via the induction of apoptosis. Based on our findings, it can be proposed that the interaction of methyl jasmonate with 5-lipoxygenase pathway may participate in the observed anticarcinogenic property.

Topics: Acetates; Anticarcinogenic Agents; Apoptosis; Arachidonate 5-Lipoxygenase; Cell Cycle; Cell Line, Tumor; Cyclopentanes; Humans; Male; Oxylipins; Prostatic Neoplasms