ABSTRACT

Liver cancer (LC) is the third largest contributor to mortality related to malignancies worldwide. The study was directed toward exploring the effects of miR-223 on LC proliferation and apoptosis. Dual luciferase reporter assay (DLRA) was carried out to verify the direct relationship of TLR4 mRNA 3′-UTR and miR-223-3p. HepG2 cells subsequently were transfected with miR-223 mimics. MTT assay and flow cytometric assay were carried out to evaluate proliferation and cell death, respectively. Toll-like receptor 4 (TLR4) transcription and translation were examined via qRT-PCR and western blotting, respectively. We observed that the miR-223 expression in LC tissues was inhibited, accompanied by reinforced TLR4 expression. Excessive miR-223 expression noticeably inhibited cell growth and promoted apoptosis in HepG2 and Bel-7402 HCC cell lines. Additionally, knockdown of TLR4 expression could suppress cell growth and promote apoptosis in HepG2 and Bel-7402 HCC cell lines. Moreover, TLR4 expression was suppressed via miR-223 transfection. T DLRA verified that miR-223 directly targeted TLR4. TLR4 over-expression canceled the effects of miR-223 on LC proliferation and apoptosis. Collectively, our findings suggest that miR-223 is an inhibitor of malignancy and participates in the inhibition of malignancy generation and reinforcement of LC cell death by targeting TLR4.

摘要

肝癌（LC）是导致世界范围内与恶性肿瘤相关的死亡率的第三大因素。该研究旨在探索miR-223对LC增殖和凋亡的影响。进行双重荧光素酶报告基因分析（DLRA）以验证TLR4 mRNA 3'-UTR和miR-223-3p的直接关系。随后用miR-223模拟物转染HepG2细胞。进行MTT测定和流式细胞术测定以分别评估增殖和细胞死亡。Toll样受体4（TLR4）的转录和翻译分别通过qRT-PCR和Western blotting检查。我们观察到，LC组织中的miR-223表达受到抑制，并伴有增强的TLR4表达。过量的miR-223表达明显抑制HepG2和Bel-7402 HCC细胞株的细胞生长并促进其凋亡。另外，敲低TLR4表达可以抑制HepG2和Bel-7402 HCC细胞株的细胞生长并促进其凋亡。此外，经由miR-223转染抑制了TLR4表达。T DLRA证实miR-223直接靶向TLR4。TLR4的过表达取消了miR-223对LC增殖和凋亡的影响。总的来说，我们的发现表明miR-223是恶性肿瘤的抑制剂，并通过靶向TLR4参与恶性肿瘤的抑制和LC细胞死亡的增强。