Existing literature has highlighted the tumour suppressive capacity of microRNA-15a (miR-15a); however, its role in hepatocellular carcinoma (HCC) remains relatively unknown. This study aimed to investigate the role of miR-15a in HCC and the associated underlying mechanism. Initially, RT-qPCR was performed to detect the expression of miR-15a in HCC tissues and cells. Bioinformatics analysis, Pearson correlation coefficient, dual-luciferase reporter assay, and molecular approaches were all conducted to ascertain the interaction between miR-15a and O-linked N-acetylglucosamine (GlcNAc) transferase (OGT). PUGNAc treatment and cycloheximide (CHX) assay were performed to evaluate O-GlcNAc and the stabilization of the enhancer of zeste homolog 2 (EZH2). Finally, gain- and loss-of-function studies were employed to elucidate the role of P53 and the miR-15a/OGT/EZH2 axis in the progression of HCC, followed by in vivo experiments based on tumour-bearing nude mice. Our results demonstrated that the miR-15a expression was decreased in the HCC tissues and cells. P53 upregulated miR-15a expression, which inhibited the proliferation, migration and invasion of HCC cells, while inducing apoptosis and triggering a G0/G1 cell cycle phase arrest. OGT stabilized EZH2 via catalysing O-GlcNAc, which reversed the effect of P53 and miR-15a. The results of our in vivo study provided evidence demonstrating that P53 could suppress the development of HCC via the miR-15a/OGT/EZH2 axis. P53 was found to inhibit the OGT expression by promoting the expression of miR-15a, which destabilized EZH2 and suppressed the development of HCC. The key findings of our study highlight a promising novel therapeutic strategy for the treatment of HCC.

中文翻译：

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P53 通过降低 OGT 表达和 EZH2 稳定化通过 miR-15a 抑制肝细胞癌的进展

现有文献强调了 microRNA-15a (miR-15a) 的肿瘤抑制能力；然而，它在肝细胞癌（HCC）中的作用仍然相对未知。本研究旨在探讨 miR-15a 在 HCC 中的作用及其相关的潜在机制。最初，进行 RT-qPCR 以检测 miR-15a 在 HCC 组织和细胞中的表达。生物信息学分析、Pearson 相关系数、双荧光素酶报告基因分析和分子方法均用于确定 miR-15a 和 O-连接的 N-乙酰氨基葡萄糖 (GlcNAc) 转移酶 (OGT) 之间的相互作用。进行 PUGNAc 处理和放线菌酮 (CHX) 测定以评估 O-GlcNAc 和 zeste 同源物 2 (EZH2) 增强剂的稳定性。最后，获得和丧失功能研究用于阐明 P53 和 miR-15a/OGT/EZH2 轴在 HCC 进展中的作用，然后是基于荷瘤裸鼠的体内实验。我们的结果表明，miR-15a 在 HCC 组织和细胞中的表达降低。P53 上调 miR-15a 的表达，从而抑制 HCC 细胞的增殖、迁移和侵袭，同时诱导细胞凋亡并触发 G0/G1 细胞周期期阻滞。OGT 通过催化 O-GlcNAc 稳定 EZH2，从而逆转 P53 和 miR-15a 的作用。我们的体内研究结果提供了证据，证明 P53 可以通过 miR-15a/OGT/EZH2 轴抑制 HCC 的发展。发现 P53 通过促进 miR-15a 的表达来抑制 OGT 的表达，这使 EZH2 不稳定并抑制了 HCC 的发展。我们研究的主要发现强调了一种治疗 HCC 的有前景的新型治疗策略。