Tsutsumi Yoko, Nomiyama Takashi, Kawanami Takako, Hamaguchi Yuriko, Terawaki Yuichi, Tanaka Tomoko, Murase Kunitaka, Motonaga Ryoko, Tanabe Makito, Yanase Toshihiko
Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
PLoS One. 2015 Oct 6;10(10):e0139709. doi: 10.1371/journal.pone.0139709. eCollection 2015.
Recently, the pleiotropic benefits of incretin-based therapy have been reported. We have previously reported that Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, attenuates prostate cancer growth. Metformin is known for its anti-cancer effect. Here, we examined the anti-cancer effect of Exendin-4 and metformin using a prostate cancer model.
Prostate cancer cells were treated with Exendin-4 and/or metformin. Cell proliferation was quantified by growth curves and 5-bromo-2'-deoxyuridine (BrdU) assay. TUNEL assay and AMP-activated protein kinase (AMPK) phosphorylation were examined in LNCaP cells. For in vivo experiments, LNCaP cells were transplanted subcutaneously into the flank region of athymic mice, which were then treated with Exendin-4 and/or metformin. TUNEL assay and immunohistochemistry were performed on tumors.
Exendin-4 and metformin additively decreased the growth curve, but not the migration, of prostate cancer cells. The BrdU assay revealed that both Exendin-4 and metformin significantly decreased prostate cancer cell proliferation. Furthermore, metformin, but not Exendin-4, activated AMPK and induced apoptosis in LNCaP cells. The anti-proliferative effect of metformin was abolished by inhibition or knock down of AMPK. In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment. Immunohistochemistry on tumors revealed that the P504S and Ki67 expression decreased by Exendin-4 and/or metformin, and that metformin increased phospho-AMPK expression and the apoptotic cell number.
These data suggest that Exendin-4 and metformin attenuated prostate cancer growth by inhibiting proliferation, and that metformin inhibited proliferation by inducing apoptosis. Combined treatment with Exendin-4 and metformin attenuated prostate cancer growth more than separate treatments.
最近，基于肠促胰岛素疗法的多效性益处已有报道。我们之前曾报道，胰高血糖素样肽-1（GLP-1）受体激动剂艾塞那肽-4可减弱前列腺癌的生长。二甲双胍以其抗癌作用而闻名。在此，我们使用前列腺癌模型研究了艾塞那肽-4和二甲双胍的抗癌作用。
用艾塞那肽-4和/或二甲双胍处理前列腺癌细胞。通过生长曲线和5-溴-2'-脱氧尿苷（BrdU）测定法对细胞增殖进行定量。在LNCaP细胞中检测TUNEL测定法和AMP活化蛋白激酶（AMPK）磷酸化。对于体内实验，将LNCaP细胞皮下移植到无胸腺小鼠的胁腹区域，然后用艾塞那肽-4和/或二甲双胍进行处理。对肿瘤进行TUNEL测定法和免疫组织化学检测。
艾塞那肽-4和二甲双胍可累加降低前列腺癌细胞的生长曲线，但不影响其迁移。BrdU测定法显示，艾塞那肽-4和二甲双胍均显著降低前列腺癌细胞增殖。此外，二甲双胍而非艾塞那肽-4可激活LNCaP细胞中的AMPK并诱导细胞凋亡。抑制或敲低AMPK可消除二甲双胍的抗增殖作用。在体内，艾塞那肽-4和二甲双胍可显著减小肿瘤大小，联合治疗后观察到肿瘤大小进一步显著减小。对肿瘤进行的免疫组织化学检测显示，艾塞那肽-4和/或二甲双胍可降低P504S和Ki67表达，且二甲双胍可增加磷酸化AMPK表达和凋亡细胞数量。
这些数据表明，艾塞那肽-4和二甲双胍通过抑制增殖减弱前列腺癌生长，且二甲双胍通过诱导凋亡抑制增殖。艾塞那肽-4与二甲双胍联合治疗比单独治疗更能减弱前列腺癌生长。
