Long noncoding RNA CASC2c inhibited cell proliferation in hepatocellular carcinoma by inactivated ERK1/2 and Wnt/β-catenin signaling pathway

Abstract

Purpose: Long non-coding RNAs (lncRNAs) have been shown to play important roles in tumorigenesis, but their biological functions and the underlying molecular mechanisms remain unclear. Alternative splicing of five exons results in three transcript variants of cancer susceptibility 2 (CASC2): the lncRNAs CASC2a, CASC2b, and CASC2c. CASC2a/b have been found to have crucial regulatory functions in a number of malignancies, but few studies have examined the effects of CASC2c in cancers. The objective of the study was to investigate the role of CASC2c in the proliferation and apoptosis of hepatocellular carcinoma (HCC) cells. Methods: This study first investigated the expression levels of CASC2c in tumor tissues, corresponding non-tumor tissues and cells using quantitative real-time polymerase chain reaction. The function and underlying molecular mechanism of CASC2c in human HCC were investigated in QGY-7703 cell line, as well as in gastric cancer (GC) cell and colorectal cancer (CRC) cell. Results: In the present work, we observed that CASC2c was significantly down-regulated in HCC tissues and cells. Moreover, its overexpression remarkably inhibited the growth, migration, and invasion of HCC cells in vitro and promoted their apoptosis. Furthermore, we demonstrated that CASC2c overexpression decreased p-ERK1/2 levels in HCC, GC, and CRC cells. Interestingly, while overexpression of CASC2c decreased β-catenin expression in HCC and GC cells, it increased that in CRC cells. Conclusion: The lncRNA–CASC2c has a vital role in tumorigenesis and cancer progression, and may serve as a biomarker or therapeutic target in cancer treatment via down-regulation of the ERK1/2 and Wnt/β-catenin signaling pathways.