methyl-jasmonate and Urinary-Bladder-Neoplasms

Gambogic acid (GA) and methyl jasmonate (MJ) are increasingly being recognized as novel natural anticancer compounds. Here, we investigated the antitumour effects of GA in combination with MJ on human bladder cancer cells.. Cell viability was detected by cell counting kit-8 assay. Cell apoptosis was assessed by Hoechst 33258 staining and flow cytometry. Protein levels were determined by immunoblotting and expressions of mRNA and miRNAs by RT-PCR. Differential expressions of a group of downstream genes were identified using microarray analysis.. MJ significantly sensitized bladder cancer cells to GA-induced growth inhibition and apoptosis while sparing normal fibroblasts. MJ enhanced GA-induced activation of caspase-3 and caspase-9, and down-regulated the expression of XIAP. Furthermore, treatment of bladder cancer cells with a combination of GA and MJ induced synergistic inhibition of the enhancer of zeste homologue 2 (EZH2) expression, whereas miR-101 expression was up-regulated. Conversely, knockdown of miR-101 restored this decreased expression of EZH2 and suppressed the inhibitory effect of GA and MJ on the growth of bladder cancer cells. Microarray analysis showed that genes closely associated with bladder cancer development were significantly down-regulated by GA and MJ. In a s.c. xenograft mouse model of human bladder carcinoma, the combination of GA and MJ exerted an increased antitumour effect compared with GA alone.. MJ sensitizes bladder cancer cells to GA-induced apoptosis by down-regulating the expression of EZH2 induced by miR-101. Thus, the combination of selective anti-cancer agents MJ and GA could provide a novel strategy for treating human bladder cancer.

Topics: Acetates; Animals; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cyclopentanes; Drug Synergism; Enhancer of Zeste Homolog 2 Protein; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Mice, Nude; MicroRNAs; Middle Aged; Neoplasm Proteins; Oxylipins; Polycomb Repressive Complex 2; Random Allocation; RNA, Neoplasm; Tumor Cells, Cultured; Urinary Bladder; Urinary Bladder Neoplasms; Xanthones; Xenograft Model Antitumor Assays

Methyl jasmonate (MJ) has recently attracted attention as a promising antitumoral compound because of its highly specific proapoptotic properties in a wide range of malignancies. However, the high doses required to achieve a therapeutic benefit have limited its clinical development. Here, we hypothesize that the family of inhibitor of apoptosis proteins (IAPs) may inhibit MJ-mediated apoptosis in cancer cells. We combined MJ with the IAPs inhibitor, the second mitochondria-derived activator of caspases (Smac) peptide to treat bladder cancer cells. The results showed that the combination of MJ and Smac peptide enhanced the apoptosis-inducing effect in a synergistic manner by releasing and activating IAPs-bounding caspase-3. These findings suggest that the inhibition of IAPs could overcome the resistance of cancer cells to MJ.

Topics: Acetates; Antennapedia Homeodomain Protein; Antineoplastic Agents; Apoptosis; Bisbenzimidazole; Caspase 3; Caspase 9; Cell Survival; Cyclopentanes; Drosophila Proteins; Drug Evaluation, Preclinical; Drug Synergism; Fluorescent Dyes; HEK293 Cells; Humans; Inhibitor of Apoptosis Proteins; Molecular Targeted Therapy; Oligopeptides; Oxylipins; Survivin; Tumor Cells, Cultured; Urinary Bladder Neoplasms; X-Linked Inhibitor of Apoptosis Protein