Liu Xueqian, Jiang Dong, Liu Yang, Xie Kun, Zhao Yijun, Liu Fubao
Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Cytojournal. 2024 Nov 25;21:53. doi: 10.25259/Cytojournal_109_2024. eCollection 2024.
Long non-coding RNAs (lncRNAs) participate in the formation, progression, and metastasis of cancer. This study aimed to explore the roles of the lncRNA ST8SIA6 antisense RNA 1 (ST8SIA6-AS1) in tumorigenesis and elucidate the underlying molecular mechanism of its upregulation in hepatocellular carcinoma (HCC).
A total of 56 in-house pairs of HCC tissues were examined, and ST8SIA6-AS1 levels were determined through real-time polymerase chain reaction (PCR). The biological behavior of ST8SIA6-AS1 by Crispr-Cas9-based gene repression and activation was determined and . The binding sites and biological behavior of Myc proto-oncogene and forkhead box A on chromatin were investigated through luciferase reporter assays, chromatin immunoprecipitation-quantitative PCR, and co-immunoprecipitation (co-IP) assays. The regulatory mechanisms of ST8SIA6-AS1 expression were analyzed with encyclopedia of DNA elements and gene expression profiling interactive analysis.
The expression of ST8SIA6-AS1 significantly increased in multiple HCC cell lines and the 56 in-house pairs of HCC tissues ( = 0.0018). Functionally, high-efficiency Crispr-Cas9-based knockdown of ST8SIA6-AS1 revealed that ST8SIA6-AS1 knockdown attenuated the proliferation, migration, and infiltration of HCC cells and considerably reduced the growth rate of subcutaneous and orthotopic HCC tumors. Conversely, ST8SIA6-AS1 overexpression considerably improved the oncogenic characteristics of the HCC cells. Furthermore, ST8SIA6-AS1 upregulation was regulated by the direct binding of transcription factor Myc to the -260 bp to+155 bp and +1003 bp to +1312 bp regions of the ST8SIA6-AS1 transcription start site, which is a segment with high level of H3K27 acetylation. Myc knockdown or treatment with the BET bromodomain inhibitor JQ-1 considerably reduced ST8SIA6-AS1 RNA expression in the HCC cells.
Our study has established the oncogenic role of ST8SIA6-AS1 and elucidated the Myc-dependent upregulation mechanism of ST8SIA6-AS1 in HCC, providing a profound theoretical molecular basis for the carcinogenic function of ST8SIA6-AS1 in HCC.
长链非编码RNA（lncRNA）参与癌症的形成、进展和转移。本研究旨在探讨lncRNA ST8SIA6反义RNA 1（ST8SIA6-AS1）在肿瘤发生中的作用，并阐明其在肝细胞癌（HCC）中上调的潜在分子机制。
共检测了56对内部HCC组织样本，通过实时聚合酶链反应（PCR）测定ST8SIA6-AS1水平。利用基于Crispr-Cas9的基因抑制和激活技术确定ST8SIA6-AS1的生物学行为。通过荧光素酶报告基因检测、染色质免疫沉淀-定量PCR和免疫共沉淀（co-IP）检测研究Myc原癌基因和叉头框A在染色质上的结合位点及生物学行为。利用DNA元件百科全书和基因表达谱交互分析对ST8SIA6-AS1表达的调控机制进行分析。
ST8SIA6-AS1在多种HCC细胞系和56对内部HCC组织样本中的表达显著增加（P = 0.0018）。在功能上，基于Crispr-Cas9的高效敲低ST8SIA6-AS1显示，敲低ST8SIA6-AS1可减弱HCC细胞的增殖、迁移和浸润，并显著降低皮下和原位HCC肿瘤的生长速度。相反，ST8SIA6-AS1过表达显著改善了HCC细胞的致癌特性。此外，ST8SIA6-AS1的上调是由转录因子Myc直接结合到ST8SIA6-AS1转录起始位点的-260 bp至+155 bp和+1003 bp至+1312 bp区域所调控的，该区域是一个H3K27乙酰化水平较高的片段。敲低Myc或用BET溴结构域抑制剂JQ-1处理可显著降低HCC细胞中ST8SIA6-AS1 RNA的表达。
我们的研究确立了ST8SIA6-AS1的致癌作用，并阐明了HCC中ST8SIA6-AS1的Myc依赖性上调机制，为ST8SIA6-AS1在HCC中的致癌功能提供了深刻的理论分子基础。
