This study aimed to explore the role of miR-222-3p in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). MiR-222-3p expression in tumor tissues of HBV (+) or HBV (−) HCC patients and corresponding cell lines was detected by quantitative reverse transcription PCR (qRT-PCR). Cell proliferation was assessed by cell counting kit-8 (CCK-8) and colony formation assays. Cell apoptosis was evaluated by flow cytometry. The potential targets of miR-222-3p were predicted by Targetscan, and the binding relationship between miR-222-3p and thrombospondin-1 (THBS1) was determined by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. MiR-222-3p was significantly upregulated in HCC tissues and cell lines and further elevated by HBV infection. MiR-222-3p downregulation effectively inhibited the proliferation and induced the apoptosis of HBV (−) HepG2 cells, HBV (+) HepG2.2.15 cells, Huh7-V cells, and Huh7-HBV cells. In addition, miR-222-3p overexpression enhanced the proliferation of these cell lines but exhibited no obvious effect on their apoptosis. Mechanistically, miR-222-3p was directly bound to the 3’-UTR of THBS1 and acted as its competing endogenous RNA (ceRNA). Interestingly, THBS1 silencing attenuated the inhibitory effect of miR-222-3p downregulation on the proliferation of these cell lines in vitro. Our results revealed that HBV infection further increased miR-222-3p expression and promoted HCC progression via miR-222-3p-mediated THBS1 downregulation. Our findings suggest that miR-222-3p might be a potential diagnostic and therapeutic target for HCC and HBV-related HCC.

本研究旨在探讨 miR-222-3p 在乙型肝炎病毒 (HBV) 相关肝细胞癌 (HCC) 中的作用。通过定量逆转录PCR（qRT-PCR）检测HBV（+）或HBV（-）HCC患者的肿瘤组织和相应细胞系中的MiR-222-3p表达。通过细胞计数试剂盒 8 (CCK-8) 和集落形成测定法评估细胞增殖。通过流式细胞术评估细胞凋亡。通过Targetscan预测miR-222-3p的潜在靶点，通过荧光素酶报告基因分析和RNA免疫沉淀（RIP）分析确定miR-222-3p与血小板反应蛋白1（THBS1）的结合关系。MiR-222-3p 在 HCC 组织和细胞系中显着上调，并因 HBV 感染而进一步升高。MiR-222-3p下调有效抑制HBV（-）HepG2细胞、HBV（+）HepG2.2.15细胞、Huh7-V细胞和Huh7-HBV细胞的增殖并诱导其凋亡。此外，miR-222-3p过表达增强了这些细胞系的增殖，但对其凋亡没有明显影响。从机制上讲，miR-222-3p 直接与 THBS1 的 3'-UTR 结合，并充当其竞争性内源性 RNA (ceRNA)。有趣的是，THBS1 沉默减弱了 miR-222-3p 下调对这些细胞系体外增殖的抑制作用。我们的研究结果表明，HBV 感染通过 miR-222-3p 介导的 THBS1 下调进一步增加了 miR-222-3p 的表达并促进了 HCC 的进展。我们的研究结果表明，miR-222-3p 可能是 HCC 和 HBV 相关 HCC 的潜在诊断和治疗靶点。