Zhang Rongrong, Zhang Ping, Wang Hong, Hou Dongming, Li Wentao, Xiao Guishan, Li Chenwei
Department of Gynecology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200092, China.
Department of Otolaryngology & Head and Neck Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200092, China.
Stem Cell Res Ther. 2015 Dec 30;6:262. doi: 10.1186/s13287-015-0249-0.
Although metformin, a first-line drug for treating diabetes, may play an important role in inhibition of epithelial ovarian cancer cell growth and cancer stem cells (CSCs), metformin at low dose showed less effect on the proliferation of ovarian cancer cells. In this study, we evaluated the effect of metformin at low dose on ovarian CSCs in order to understand the molecular mechanisms underlying.
The inhibitory effects of metformin at los dose on proliferation and population of ovarian cancer cells including SKOV3 and A2780 were assessed by cell proliferation assay and flow cytometry. Quantitative real-time PCR assay on expression of Bcl-2, Survivin and Bax was performed to determine the effect of metformin at low dose on epithelial-mesenchymal transition (EMT) of cancer cells and CSCs. Tumor sphere formation assay was also performed to evaluate the effect of metformin on spheres forming ability of CSCs. The therapeutic efficacy and the anti-CSC effects of metformin at low dose were investigated by using both SKOV3 cells and primary tumor xenografts. In addition, the CSC frequency and EMT in tumor xenograft models were also assessed by flow cytometry and quantitative real-time PCR.
Metformin at low dose did not affect the proliferation of ovarian cancer cells. However, it inhibited population of CD44(+)CD117(+) selectively, neither CD133(+) nor ALDH(+) cells. It suppressed expression of snail2, twist and vimentin significantly in cancer cells and CD44(+)CD117(+) CSCs in vitro. Low dose of metformin reduced survivin expression in CSCs. Low concentrations of metformin inhibited the secondary and the tertiary tumor sphere formation, decreased SKOV3 and primary ovarian tumor xenograft growth, enhanced the anticancer effect of cisplatin, and lowered the proportion of CD44(+)CD117(+) CSCs in the xenograft tissue. Metformin was also associated with a reduction of snail2, twist, and vimentin in CD44(+)CD117(+) ovarian CSCs in vivo.
Our results implicate that metformin at low dose inhibits selectively CD44(+)CD117(+) ovarian CSCs through inhibition of EMT and potentiates the effect of cisplatin.
尽管二甲双胍作为治疗糖尿病的一线药物，可能在抑制上皮性卵巢癌细胞生长和癌症干细胞（CSCs）方面发挥重要作用，但低剂量二甲双胍对卵巢癌细胞增殖的影响较小。在本研究中，我们评估了低剂量二甲双胍对卵巢CSCs的影响，以了解其潜在的分子机制。
通过细胞增殖试验和流式细胞术评估低剂量二甲双胍对包括SKOV3和A2780在内的卵巢癌细胞增殖和群体的抑制作用。进行定量实时PCR检测Bcl-2、Survivin和Bax的表达，以确定低剂量二甲双胍对癌细胞和CSCs上皮-间质转化（EMT）的影响。还进行了肿瘤球形成试验，以评估二甲双胍对CSCs形成球能力的影响。使用SKOV3细胞和原发性肿瘤异种移植模型研究低剂量二甲双胍的治疗效果和抗CSC作用。此外，还通过流式细胞术和定量实时PCR评估肿瘤异种移植模型中的CSC频率和EMT。
低剂量二甲双胍不影响卵巢癌细胞的增殖。然而，它选择性地抑制CD44(+)CD117(+)细胞群体，对CD133(+)和ALDH(+)细胞均无影响。它在体外显著抑制癌细胞和CD44(+)CD117(+)CSCs中snail2、twist和波形蛋白的表达。低剂量二甲双胍降低了CSCs中Survivin的表达。低浓度二甲双胍抑制二级和三级肿瘤球形成，减少SKOV3和原发性卵巢肿瘤异种移植的生长，增强顺铂的抗癌作用，并降低异种移植组织中CD44(+)CD117(+)CSCs的比例。二甲双胍还与体内CD44(+)CD117(+)卵巢CSCs中snail2、twist和波形蛋白的减少有关。
我们的结果表明，低剂量二甲双胍通过抑制EMT选择性地抑制CD44(+)CD117(+)卵巢CSCs，并增强顺铂的作用。
