LINC01348 suppresses hepatocellular carcinoma metastasis through inhibition of SF3B3-mediated EZH2 pre-mRNA splicing

Oncogene. 2021 Jul;40(28):4675-4685. doi: 10.1038/s41388-021-01905-3. Epub 2021 Jun 17.

Abstract

Long non-coding RNAs (lncRNA) play crucial roles in hepatocellular carcinoma (HCC) progression. However, the specific functions of lncRNAs in alternative splicing (AS) and the metastatic cascade in liver cancer remain largely unclear. In this study, we identified a novel lncRNA, LINC01348, which was significantly downregulated in HCC and correlated with survival functions in HCC patients. Ectopic expression of LINC01348 induced marked inhibition of cell growth, and metastasis in vitro and in vivo. Conversely, these phenotypes were reversed upon knockdown of LINC01348. Mechanistically, LINC01348 complexed with splicing factor 3b subunit 3 (SF3B3) acted as a modulator of EZH2 pre-mRNA AS, and induced alterations in JNK/c-Jun activity and expression of Snail. Notably, C-terminal truncated HBx (Ct-HBx) negatively regulated LINC01348 through c-Jun signaling. Our data collectively highlight those novel regulatory associations involving LINC01348/SF3B3/EZH2/JNK/c-Jun/Snail are an important determinant of metastasis in HCC cells and support the potential utility of targeting LINC01348 as a therapeutic strategy for HCC.

MeSH terms

  • Alternative Splicing
  • Animals
  • Carcinoma, Hepatocellular* / genetics
  • Carcinoma, Hepatocellular* / metabolism
  • Carcinoma, Hepatocellular* / pathology
  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • Enhancer of Zeste Homolog 2 Protein* / genetics
  • Enhancer of Zeste Homolog 2 Protein* / metabolism
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Liver Neoplasms* / genetics
  • Liver Neoplasms* / metabolism
  • Liver Neoplasms* / pathology
  • Male
  • Mice
  • Mice, Nude
  • Neoplasm Metastasis
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA Splicing / genetics
  • RNA Splicing Factors* / genetics
  • RNA Splicing Factors* / metabolism
  • RNA, Long Noncoding* / genetics
  • RNA, Long Noncoding* / metabolism

Substances

  • Enhancer of Zeste Homolog 2 Protein
  • EZH2 protein, human
  • RNA Precursors
  • RNA Splicing Factors
  • RNA, Long Noncoding
  • SF3B3 protein, human