Department of Obstetrics and Gynecology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China.
Int J Gynecol Cancer. 2012 Jan;22(1):15-22. doi: 10.1097/IGC.0b013e3182322834.
The phosphoinositide 3 kinase (PI3K)/v-akt murine thymoma viral oncogene homolog (AKT)/mammalian target of rapamycin (mTOR) pathway is frequently aberrantly activated in ovarian cancer and confers the chemoresistant phenotype of ovarian cancer cells. LY294002 (PI3K inhibitor) and metformin (5'-adenosine monophosphate [AMP]-activated protein kinase [AMPK] activator) are 2 drugs that were known to inhibit mTOR expression through the AKT-dependent and AKT-independent pathways, respectively. In this study, we explored the effectiveness of LY294002 and metformin in combination on inhibition of ovarian cancer cell growth.
Western blotting was used to detect the changes of PI3K/AKT/mTOR and AMPK/acetyl-CoA carboxylase (ACC) signaling activities, cell cycle control, and apoptosis. Cell growth was evaluated by cell proliferation, colony formation, and soft agar assays. Flow cytometry was used to study cell cycle distribution and cell death upon drug treatment.
Our study showed that LY294002 and metformin in combination could simultaneously enhance the repression of the PI3K/AKT/mTOR pathway and the activation of the AMPK/ACC pathway. The downstream target of AKT and AMPK, mTOR, was cooperatively repressed when the drugs were used together. The cell cycle regulatory factors, p53, p27, and p21, were up-regulated. On the other hand, caspase 3 and poly (ADP-ribose) polymerase activities involved in apoptosis were also activated. Cell growth assays indicated that LY294002 and metformin could effectively inhibit ovarian cancer cell growth. Flow cytometry analysis showed that the treatment of the 2 drugs mentioned above induced cell cycle arrest at G1 phase and increased sub-G1 apoptotic cells.
The combinational use of LY294002 and metformin can enhance inhibition of the growth and induction of the apoptosis of ovarian cancer cells. Our results may provide significant insight into the future therapeutic regimens in ovarian cancer.
磷酸肌醇 3 激酶（PI3K）/v-akt 鼠胸腺瘤病毒癌基因同源物（AKT）/哺乳动物雷帕霉素靶蛋白（mTOR）途径在卵巢癌中经常异常激活，并赋予卵巢癌细胞的化疗耐药表型。LY294002（PI3K 抑制剂）和二甲双胍（5'-腺苷一磷酸 [AMP]-激活的蛋白激酶 [AMPK] 激活剂）是两种通过 AKT 依赖性和 AKT 非依赖性途径分别抑制 mTOR 表达的药物。在这项研究中，我们探讨了 LY294002 和二甲双胍联合使用对抑制卵巢癌细胞生长的效果。
使用 Western 印迹检测 PI3K/AKT/mTOR 和 AMPK/乙酰辅酶 A 羧化酶（ACC）信号通路、细胞周期调控和细胞凋亡的变化。通过细胞增殖、集落形成和软琼脂测定评估细胞生长。流式细胞术用于研究药物处理后细胞周期分布和细胞死亡。
我们的研究表明，LY294002 和二甲双胍联合使用可以同时增强 PI3K/AKT/mTOR 通路的抑制和 AMPK/ACC 通路的激活。当药物联合使用时，AKT 和 AMPK 的下游靶标 mTOR 被协同抑制。细胞周期调节因子 p53、p27 和 p21 上调。另一方面，参与细胞凋亡的 caspase 3 和多聚（ADP-核糖）聚合酶活性也被激活。细胞生长测定表明，LY294002 和二甲双胍可以有效抑制卵巢癌细胞生长。流式细胞术分析表明，上述两种药物的联合处理诱导细胞周期停滞在 G1 期，并增加了亚 G1 凋亡细胞。
LY294002 和二甲双胍的联合使用可以增强对卵巢癌细胞生长的抑制和诱导凋亡。我们的结果可能为卵巢癌的未来治疗方案提供重要的见解。
