Hijaz M, Chhina J, Mert I, Taylor M, Dar S, Al-Wahab Z, Ali-Fehmi R, Buekers T, Munkarah A R, Rattan R
Department of Women's Health, Henry Ford Hospital, 1 Ford Place, Detroit, MI, USA.
Department of Obstetrics and Gynecology, Wayne State University, 42 W Warren Ave, Detroit, MI, USA.
Gynecol Oncol. 2016 Aug;142(2):323-31. doi: 10.1016/j.ygyno.2016.06.005. Epub 2016 Jun 16.
BRCA mutated ovarian cancers show increased responsiveness to PARP inhibitors. PARP inhibitors target DNA repair and provide a second hit to BRCA mutated tumors, resulting in "synthetic lethality". We investigated a combination of metformin and olaparib to provide "synthetic lethality" in BRCA intact ovarian cancer cells.
Ovarian cancer cell lines (UWB1.289, UWB1.289.BRCA, SKOV3, OVCAR5, A2780 and C200) were treated with a combination of metformin and olaparib. Cell viability was assessed by MTT and colony formation assays. Flow cytometry was used to detect cell cycle events. In vivo studies were performed in SKOV3 or A2780 xenografts in nude mice. Animals were treated with single agent, metformin or olaparib or combination. Molecular downstream effects were examined by immunohistochemistry.
Compared to single drug treatment, combination of olaparib and metformin resulted in significant reduction of cell proliferation and colony formation (p<0.001) in ovarian cancer cells. This treatment was associated with a significant S-phase cell cycle arrest (p<0.05). Combination of olaparib and metformin significantly inhibited SKOV3 and A2780 ovarian tumor xenografts which were accompanied with decreased Ki-index (p<0.001). Metformin did not affect DNA damage signaling, while olaparib induced adenosine monophosphate activated kinase activation; that was further potentiated with metformin combination in vivo.
Combining PARP inhibitors with metformin enhances its anti-proliferative activity in BRCA mutant ovarian cancer cells. Furthermore, the combination showed significant activity in BRCA intact cancer cells in vitro and in vivo. This is a promising treatment regimen for women with epithelial ovarian cancer irrespective of BRCA status.
携带BRCA突变的卵巢癌对PARP抑制剂显示出更高的反应性。PARP抑制剂靶向DNA修复，对携带BRCA突变的肿瘤造成“二次打击”，从而导致“合成致死”。我们研究了二甲双胍和奥拉帕利联合使用，以在BRCA基因完整的卵巢癌细胞中产生“合成致死”效应。
用二甲双胍和奥拉帕利联合处理卵巢癌细胞系（UWB1.289、UWB1.289.BRCA、SKOV3、OVCAR5、A2780和C200）。通过MTT和集落形成试验评估细胞活力。采用流式细胞术检测细胞周期事件。在裸鼠的SKOV3或A2780异种移植瘤中进行体内研究。动物接受单药、二甲双胍或奥拉帕利或联合用药治疗。通过免疫组织化学检查分子下游效应。
与单药治疗相比，奥拉帕利和二甲双胍联合使用可显著降低卵巢癌细胞的增殖和集落形成（p<0.001）。这种治疗与显著的S期细胞周期阻滞相关（p<0.05）。奥拉帕利和二甲双胍联合使用显著抑制了SKOV3和A2780卵巢肿瘤异种移植瘤，同时Ki指数降低（p<0.001）。二甲双胍不影响DNA损伤信号传导，而奥拉帕利可诱导单磷酸腺苷激活的蛋白激酶激活；在体内与二甲双胍联合使用时，这种激活作用进一步增强。
PARP抑制剂与二甲双胍联合使用可增强其在携带BRCA突变的卵巢癌细胞中的抗增殖活性。此外，该联合用药在体外和体内的BRCA基因完整的癌细胞中均显示出显著活性。对于上皮性卵巢癌患者，无论其BRCA状态如何，这都是一种有前景的治疗方案。
