Department of General Surgery, Taizhou First People's Hospital, Taizhou, Zhejiang Province 318020, P.R. China.
Department of General Surgery, The Affiliated Huangyan Hospital of Wenzhou Medical University, Taizhou, Zhejiang Province 318020, P.R. China.
Cancer Cell Int. 2014 Jun 22;14:58. doi: 10.1186/1475-2867-14-58. eCollection 2014.
MicroRNAs (miRNAs) are a large group of post-transcriptional gene regulators that potentially play a critical role in tumorigenesis. Increasing evidences indicate that miR-744 deregulated in numerous human cancers including hepatocellular carcinoma (HCC). However, its role in HCC carcinogenesis remains poorly defined. In this study, we investigated the roles of miR-744 in tumor growth of HCC.
Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was conducted to detect the expression of miR-744 and Immunohistochemistry was performed to detect expression of c-Myc in HCC specimens and adjacent normal tissues. The biological functions of miR-744 were determined by cell proliferation and cell cycle assay. Furthermore, cell lines transfected with miR-744 mimics were analyzed in vitro. Luciferase reporter assays was performed to confirm whether miR-744 regulated the expression of c-Myc.
Our results showed that the expression of miR-744 was frequently down-regulated in both HCC tissues and cells. Furthermore, restoration of miR-744 in HCC cells was statistically correlated with decrease of cell growth and restored G1 accumulation. Luciferase assay and Western blot analysis revealed that c-Myc is a direct target of miR-744. Down-regulation of miR-744 and up-regulation of c-Myc were detected in HCC specimens compared with adjacent normal tissues. Moreover, restoration of miR-744 rescues c-Myc induced HCC proliferation.
Our data suggest that miR-744 exerts its tumor suppressor function by targeting c-Myc, leading to the inhibition of HCC cell growth. miR-744 may serve as a potentially useful target for the miRNA-based therapies of HCC in the future.
微小 RNA(miRNAs)是一大类转录后基因调控因子,它们可能在肿瘤发生中发挥关键作用。越来越多的证据表明,miR-744 在包括肝细胞癌(HCC)在内的许多人类癌症中失调。然而,其在 HCC 致癌作用中的作用仍未明确定义。在这项研究中,我们研究了 miR-744 在 HCC 肿瘤生长中的作用。
采用定量逆转录聚合酶链反应(qRT-PCR)检测 miR-744 的表达,采用免疫组织化学法检测 HCC 标本和相邻正常组织中 c-Myc 的表达。通过细胞增殖和细胞周期测定来确定 miR-744 的生物学功能。此外,对转染 miR-744 模拟物的细胞系进行体外分析。进行荧光素酶报告基因测定以确认 miR-744 是否调节 c-Myc 的表达。
我们的结果表明,miR-744 的表达在 HCC 组织和细胞中均经常下调。此外,miR-744 在 HCC 细胞中的恢复与细胞生长的减少和 G1 积累的恢复呈统计学相关。荧光素酶测定和 Western blot 分析显示,c-Myc 是 miR-744 的直接靶标。与相邻正常组织相比,在 HCC 标本中检测到 miR-744 的下调和 c-Myc 的上调。此外,miR-744 的恢复可挽救 c-Myc 诱导的 HCC 增殖。
我们的数据表明,miR-744 通过靶向 c-Myc 发挥其肿瘤抑制功能,从而抑制 HCC 细胞生长。miR-744 可能成为未来 HCC 基于 miRNA 治疗的潜在有用靶点。