White-Al Habeeb Nicole M A, Garcia Julia, Fleshner Neil, Bapat Bharati
Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Prostate. 2016 Dec;76(16):1507-1518. doi: 10.1002/pros.23235. Epub 2016 Jul 12.
This study explored the biological effects of metformin on prostate cancer (PCa) cells and determined molecular pathways and epigenetic regulators implicated in its mechanism of action.
We performed mRNA expression profiling in 22Rv1 cells following 2.5 mM and 5 mM metformin treatment. Genes significantly modified by metformin treatment were ranked based on altered expression, involvement with cancer-related processes, and reported dysregulation in PCa. The effects of the top ranked gene, MMSET, on the proliferative and invasive capabilities of PCa cells were investigated via siRNA knockdown alone and also combined with metformin treatment.
Metformin treatment decreased cell growth of PCa cell line 22Rv1 and stalled cells at the G1/S checkpoint in a time- and dose-dependent manner, resulting in increased cells in G1 (P < 0.05) and decreased cells in S (P < 0.05) phase. Metformin activated the AMPK/mTOR signaling pathway as shown by increased p-AMPK and decreased p-p70S6K. mRNA expression profiling following metformin treatment identified significant changes in 136 chromatin-modifying genes. The top ranked gene, multiple myeloma SET domain (MMSET) showed increased expression in PCa cell lines (22Rv1 and DU145) when compared to the benign prostate epithelium-derived cell-line RWPE-1, and its expression was decreased upon metformin treatment. siRNA-mediated knockdown of MMSET showed decreased cellular migration and invasion in DU-145 cells. MMSET knockdown in combination with metformin treatment resulted in further reduction in the capacity of PCa cells to migrate and invade.
These data suggest MMSET may play a role in the inhibitory effect of metformin on PCa and could serve as a potential novel therapeutic target for PCa. Prostate 76:1507-1518, 2016. © 2016 Wiley Periodicals, Inc.
本研究探讨了二甲双胍对前列腺癌细胞（PCa）的生物学效应，并确定了其作用机制中涉及的分子途径和表观遗传调节因子。
我们在22Rv1细胞中进行了2.5 mM和5 mM二甲双胍处理后的mRNA表达谱分析。根据二甲双胍处理后表达改变、与癌症相关过程的参与情况以及前列腺癌中报道的失调情况，对经二甲双胍处理后显著改变的基因进行排序。通过单独的小干扰RNA（siRNA）敲低以及与二甲双胍处理联合，研究了排名最高的基因MMSET对前列腺癌细胞增殖和侵袭能力的影响。
二甲双胍处理以时间和剂量依赖性方式降低了前列腺癌细胞系22Rv1的细胞生长，并使细胞停滞在G1/S检查点，导致G1期细胞增加（P < 0.05），S期细胞减少（P < 0.05）。二甲双胍激活了AMPK/mTOR信号通路，表现为p-AMPK增加和p-p70S6K减少。二甲双胍处理后的mRNA表达谱分析确定了136个染色质修饰基因的显著变化。排名最高的基因，多发性骨髓瘤SET结构域（MMSET），与良性前列腺上皮来源的细胞系RWPE-1相比，在前列腺癌细胞系（22Rv1和DU145）中表达增加，而其表达在二甲双胍处理后降低。siRNA介导的MMSET敲低显示DU-145细胞的细胞迁移和侵袭减少。MMSET敲低与二甲双胍处理联合导致前列腺癌细胞迁移和侵袭能力进一步降低。
这些数据表明MMSET可能在二甲双胍对前列腺癌的抑制作用中发挥作用，并可能作为前列腺癌潜在的新型治疗靶点。《前列腺》76:1507 - 1518，2016年。© 2016威利期刊公司。
