Zhou Jin, Han Sheng, Qian Weichun, Gu Yuanyuan, Li Xiangcheng, Yang Kunxing
Department of General Surgery, Nanjing First Hospital, Nanjing Medical University, Nanjing, China,
Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China,
Onco Targets Ther. 2018 Jul 31;11:4451-4459. doi: 10.2147/OTT.S167614. eCollection 2018.
Metformin is one of the extensively and most commonly used oral antihyperglycemic agents, but it has been shown to exert antineoplastic effects in many cancer cells. Recent studies have confirmed that metformin has an antitumor effect on hepatocellular carcinoma (HCC). However, the molecular mechanism underlying this effect needs to be further studied.
CDK1 and miR-378 expression was analyzed by western blotting and real-time PCR assays. We confirmed the association between miR-378 and CDK1 by dual luciferase reporter assay. The role of the miR-378/CDK1 pathway in proliferation, cell cycle and apoptosis was examined in vitro. The effect of miR-378 on HCC tumor growth was evaluated in nude xenograft mouse model.
Our study found that metformin significantly inhibited the HCC cell proliferation via inducing G2/M arrest. At the same time, metformin efficiently decreased CDK1 expression and elevated miR-378 level. Moreover, the upregulation of miR-378 also repressed HCC cell proliferation by causing G2/M arrest and inhibited tumor growth. Additionally, we demonstrated that miR-378 directly targeted CDK1 3'UTR and downregulated CDK1 mRNA and protein levels. Furthermore, metformin treatment could not decrease CDK1 expression, suppress HCC cell proliferation, and induce G2/M cell cycle arrest.
Metformin-suppressed HCC cell proliferation was dependent on the inhibitory effect of miR-378 on CDK1 expression. Taken together, we concluded that metformin inhibited HCC cell proliferation via modulating miR-378/CDK1 axis.
Collectively, the current results provide the first evidence, to our knowledge, that miR-378/CDK1 axis is involved in metformin modulating the proliferation of HCC cells, which suggests a novel molecular mechanism underlying the thera peutic effect of metformin on HCC.
二甲双胍是广泛且最常用的口服抗高血糖药物之一，但已显示它在许多癌细胞中发挥抗肿瘤作用。最近的研究证实，二甲双胍对肝细胞癌（HCC）有抗肿瘤作用。然而，这种作用背后的分子机制需要进一步研究。
通过蛋白质印迹法和实时PCR分析CDK1和miR-378的表达。我们通过双荧光素酶报告基因检测证实了miR-378与CDK1之间的关联。在体外研究了miR-378/CDK1途径在增殖、细胞周期和凋亡中的作用。在裸鼠异种移植模型中评估了miR-378对HCC肿瘤生长的影响。
我们的研究发现，二甲双胍通过诱导G2/M期阻滞显著抑制HCC细胞增殖。同时，二甲双胍有效降低CDK1表达并提高miR-378水平。此外，miR-378的上调也通过引起G2/M期阻滞抑制HCC细胞增殖并抑制肿瘤生长。此外，我们证明miR-378直接靶向CDK1的3'UTR并下调CDK1的mRNA和蛋白质水平。此外，二甲双胍处理不能降低CDK1表达、抑制HCC细胞增殖并诱导G2/M期细胞周期阻滞。
二甲双胍抑制HCC细胞增殖依赖于miR-378对CDK1表达的抑制作用。综上所述，我们得出结论，二甲双胍通过调节miR-378/CDK1轴抑制HCC细胞增殖。
总体而言，据我们所知，目前的结果首次提供了证据，表明miR-378/CDK1轴参与二甲双胍调节HCC细胞增殖，这提示了二甲双胍对HCC治疗作用的一种新的分子机制。
