Xue Fei, Liu Yanhui, Zhang Hongwei, Wen Yu, Yan Lei, Tang Qiang, Xiao Erhui, Zhang Dongyi
Department of Hepatobiliary and Pancreatic Surgery, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, People's Republic of China.
Department of Hematology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, People's Republic of China.
Onco Targets Ther. 2016 Nov 28;9:7253-7261. doi: 10.2147/OTT.S116127. eCollection 2016.
Let-7 miRNAs are reported to play an inhibitory role in carcinogenesis, tumor progression, recurrence, and pluripotency of cancer. However, few studies have reported the relationship between let-7 and drug sensitivity, especially for let-7a (a subtype of let-7). This study aimed to investigate the function of let-7a in regulating the sensitivity of hepatocellular carcinoma (HCC) cell lines to cetuximab.
The cytotoxicity of cetuximab on HCC cell lines (Huh7, Hep3B, HepG2, SNU449, and SNU387) was evaluated using a cell viability assay (the Cell Counting Kit-8 assay) and a cell proliferation assay (the Click-iT EdU Imaging Kit) in the presence of a control, a let-7a mimic, and a let-7a inhibitor. Small interfering RNA to knockdown the expression of signal transducer and activator of transcription 3 (STAT3) were employed. Protein and mRNA expression levels were determined using quantitative polymerase chain reaction and Western blot analysis.
It was found that let-7a enhances the sensitivity of HCC cells with an epithelial phenotype (Huh7, Hep3B, and HepG2) to cetuximab, but has no effect on cells with the mesenchymal phenotype (SNU449 and SNU387). It was determined that STAT3 was a target mRNA of let-7a using TargetScan. Expression of STAT3 and let-7a mRNA were negatively correlated in HCC cell lines. Moreover, let-7a altered the protein and mRNA expression of STAT3. Furthermore, STAT3 knockdown enhanced the function of cetuximab on HCC cell lines with epithelial phenotypes, but not on HCC cell lines with mesenchymal phenotypes. Finally, a rescue experiment confirmed that let-7a affected the sensitivity of HCC cell lines to cetuximab by interacting with STAT3.
There is a functional link between let-7a and STAT3 in enhancing the sensitivity of HCC cells with an epithelial phenotype to cetuximab. Our results provide novel insight into new methodologies for combating HCC drug resistance.
据报道，Let-7微小RNA（miRNA）在癌症的发生、肿瘤进展、复发及多能性方面发挥抑制作用。然而，鲜有研究报道Let-7与药物敏感性之间的关系，尤其是Let-7a（Let-7的一种亚型）。本研究旨在探讨Let-7a在调节肝癌（HCC）细胞系对西妥昔单抗敏感性中的作用。
在存在对照、Let-7a模拟物和Let-7a抑制剂的情况下，使用细胞活力测定法（细胞计数试剂盒-8测定法）和细胞增殖测定法（Click-iT EdU成像试剂盒）评估西妥昔单抗对HCC细胞系（Huh7、Hep3B、HepG2、SNU449和SNU387）的细胞毒性。采用小干扰RNA敲低信号转导和转录激活因子3（STAT3）的表达。使用定量聚合酶链反应和蛋白质印迹分析测定蛋白质和mRNA表达水平。
发现Let-7a增强具有上皮表型的HCC细胞（Huh7、Hep3B和HepG2）对西妥昔单抗的敏感性，但对具有间充质表型的细胞（SNU449和SNU387）无影响。使用TargetScan确定STAT3是Let-7a的靶mRNA。在HCC细胞系中，STAT3和Let-7a mRNA的表达呈负相关。此外，Let-7a改变了STAT3的蛋白质和mRNA表达。此外，敲低STAT3增强了西妥昔单抗对具有上皮表型的HCC细胞系的作用，但对具有间充质表型的HCC细胞系无作用。最后，一项拯救实验证实Let-7a通过与STAT3相互作用影响HCC细胞系对西妥昔单抗的敏感性。
Let-7a与STAT3之间存在功能联系，可增强具有上皮表型的HCC细胞对西妥昔单抗的敏感性。我们的结果为对抗HCC耐药性的新方法提供了新见解。
