Hepatobiliary Department I, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, The College of Clinical Medicine of Hunan Normal University, Changsha, China.
Neoplasma. 2021 Jan;68(1):87-95. doi: 10.4149/neo_2020_200106N17. Epub 2020 Aug 27.
Liver cancer is the sixth most prevalent cancer worldwide and the third leading cause of cancer-related deaths. Adriamycin (ADR) resistance, which often leads to the progression of malignant tumors, is a major treatment obstacle for liver cancer. It has been confirmed that miR-155-5p could reverse drug resistance in human breast cancer. However, the biological function of miR-155-5p in ADR-resistant liver carcinoma (HepG2/ADR) cells remains unclear. miR-155-5p and ATG5 expression was determined by RT-qPCR and western blot. In addition, MTT, flow cytometry, immunofluorescence staining, and western blotting were performed to evaluate the proliferation, apoptosis, and autophagy of liver cancer cells. Finally, the effect of miR-155-5p on the expression of autophagy-related 5 (ATG5) was analyzed by luciferase activity assay, western blot, and RT-qPCR. Our results showed that miR-155-5p was downregulated in HepG2/ADR cells. Increasing the expression of miR-155-5p enhanced the sensitivity of liver carcinoma cells to ADR and promoted apoptosis through inhibition of autophagy in vitro. In addition, the binding site between miR-155-5p and ATG5 was identified, and miR-155-5p could directly regulate ATG5. Finally, ATG5 partially rescued the effect of miR-155-5p on autophagy and the apoptosis of HepG2/ADR cells. In conclusion, our findings showed that miR-155-5p could reverse ADR resistance in liver cancer by targeting ATG5, which may function as a potential target for liver cancer treatment.
肝癌是全球第六大常见癌症，也是癌症相关死亡的第三大主要原因。阿霉素（ADR）耐药性常常导致恶性肿瘤的进展，是肝癌治疗的主要障碍。已经证实 miR-155-5p 可以逆转人乳腺癌的耐药性。然而，miR-155-5p 在 ADR 耐药肝癌（HepG2/ADR）细胞中的生物学功能尚不清楚。通过 RT-qPCR 和 Western blot 测定 miR-155-5p 和 ATG5 的表达。此外，通过 MTT、流式细胞术、免疫荧光染色和 Western blot 评估肝癌细胞的增殖、凋亡和自噬。最后，通过荧光素酶活性测定、Western blot 和 RT-qPCR 分析 miR-155-5p 对自噬相关蛋白 5（ATG5）表达的影响。结果表明，miR-155-5p 在 HepG2/ADR 细胞中下调。增加 miR-155-5p 的表达可增强肝癌细胞对 ADR 的敏感性，并通过抑制自噬促进体外细胞凋亡。此外，鉴定出 miR-155-5p 和 ATG5 之间的结合位点，miR-155-5p 可以直接调节 ATG5。最后，ATG5 部分挽救了 miR-155-5p 对 HepG2/ADR 细胞自噬和凋亡的影响。总之，我们的研究结果表明，miR-155-5p 通过靶向 ATG5 可以逆转肝癌的 ADR 耐药性，这可能为肝癌的治疗提供一个潜在的靶点。
