LncRNA ANCR promotes hepatocellular carcinoma metastasis through upregulating HNRNPA1 expression

LncRNA ANCR plays important roles in the modulation of epithelial mesenchymal transition (EMT) and tumour metastasis in many tumours. However, the role of ANCR in regulating hepatocellular carcinoma (HCC) metastasis is still not known. The current study aims to investigate the underlying mechanism for tumour oncogenesis of ANCR in HCC metastasis. HCC cell proliferation and migration/invasion were measured by MTT and Transwell assays. Xenograft model was established to determine the effect of ANCR on HCC growth and metastasis. ChIP assay was used to detect the H3 and H4 histone acetylation levels at the ANCR promoter region. RNA pull-down and RIP assay was performed to analyse the relationship between ANCR and heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1). Dual-luciferase reporter gene assay was conducted to determine the interaction between ANCR and miR-140-3p. The results indicated that ANCR was highly expressed in HCC tissues and cells, which promoted the proliferation and migration/invasion of HCC cells. In vivo experiments showed interfering ANCR suppressed the growth and metastasis of HCC. H3/H4 histone acetylation levels at the ANCR promoter region were elevated in HCC tissues and cells, and interfering histone deacetylases 3 (HDAC3) significantly up-regulated ANCR expression. ANCR could bind to HNRNPA1, and promoted the expression of HNRNPA1 through regulating its degradation. In addition, ANCR upregulated the expression of HNRNPA1 through sponging miR-140-3p. Finally, we found that ANCR promoted the EMT and invasion/migration of HCC cells through regulating HNRNPA1. In conclusion, ANCR promoted HCC metastasis by upregulating HNRNPA1, inhibiting HNRNPA1 degradation and sponging miR-140-3p.

长链非编码RNA ANCR（LncRNA ANCR）在多种肿瘤的上皮间质转化（epithelial mesenchymal transition，EMT）调控与肿瘤转移进程中发挥关键作用。然而，ANCR在肝细胞癌（hepatocellular carcinoma，HCC）转移中的调控功能仍未明确。本研究旨在探究ANCR在肝细胞癌转移过程中发挥促瘤作用的潜在分子机制。本研究采用MTT实验与Transwell实验分别检测肝细胞癌细胞的增殖、迁移与侵袭能力；构建裸鼠异种移植瘤模型，以明确ANCR对肝细胞癌生长与转移的调控作用。采用染色质免疫沉淀（ChIP）实验检测ANCR启动子区域的组蛋白H3与H4乙酰化水平；通过RNA pull-down与RNA免疫沉淀（RIP）实验分析ANCR与异质性核核糖核蛋白A1（heterogeneous nuclear ribonucleoprotein A1，HNRNPA1）之间的相互作用；采用双荧光素酶报告基因实验验证ANCR与miR-140-3p的靶向结合关系。实验结果显示，ANCR在肝细胞癌组织与细胞系中呈高表达状态，可显著促进肝细胞癌细胞的增殖、迁移与侵袭能力。体内实验表明，敲低ANCR的表达可显著抑制肝细胞癌的生长与转移。肝细胞癌组织与细胞系中ANCR启动子区域的H3/H4组蛋白乙酰化水平显著升高，而抑制组蛋白去乙酰化酶3（histone deacetylases 3，HDAC3）的活性可显著上调ANCR的表达水平。ANCR可与HNRNPA1相结合，并通过调控其蛋白降解过程促进HNRNPA1的表达。此外，ANCR还可通过海绵吸附miR-140-3p上调HNRNPA1的表达。最终研究发现，ANCR可通过调控HNRNPA1的表达促进肝细胞癌细胞的上皮间质转化与侵袭迁移能力。综上，ANCR可通过上调HNRNPA1的表达、抑制其蛋白降解以及海绵吸附miR-140-3p这三种途径，促进肝细胞癌的转移进程。