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

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 ß-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/ß-catenin signaling pathways.

Effects of long non-coding RNA (lncRNA) cancer susceptibility candidate 2c (CASC2c) on proliferation, metastasis and drug resistance of non-small cell lung cancer (NSCLC) cells through ERK1/2 and ß-catenin signaling pathways.

OBJECTIVES: This study was aimed to investigate the effects of long non-coding RNA (lncRNA) cancer susceptibility candidate 2c (CASC2c) on the proliferation, metastasis and drug resistance of non-small cell lung cancer (NSCLC) cells. METHODS: The expression of CASC2c in NSCLC tissues and cell lines was detected by real-time fluorescence quantitative PCR (RT-qPCR). MTT and Transwell assay were used to determine the proliferation and migration of NSCLC cells in the experimental group and the control group respectively. The drug sensitivity test was used to confirm whether increasing the CASC2c expression level could reverse the resistance of NSCLC cells to the chemotherapy drug cisplatin. The effects of CASC2c on the expression levels of p-ERK1/2 and ß-catenin were detected by western blot. RESULTS: The results of RT-qPCR showed that CASC2c was under-expressed in NSCLC tissues and cells compared with normal adjacent lung tissues cells (p < 0.05). In addition, the CASC2c expression was remarkably correlated with TNM staging, tumor cell differentiation, lymph node metastasis, smoking and other pathological indicators of patients with NSCLC (p < 0.05). MTT and Transwell assay showed that the high-expression of CASC2c significantly reduced the proliferation and migration of NSCLC cells compared to that of the control group (p < 0.05). Western blot assay showed that the high-expressed CASC2c can decrease the expression of phosphorylated-ERK1/2 (p-ERK1/2) and ß-catenin. CONCLUSIONS: CASC2c was low expressed in NSCLC tissues and cells. What's more, it inhibited the proliferation and migration of NSCLC cells by inhibiting the expression of p-ERK1/2 and ß-catenin and reversed NSCLC cells' resistance to the chemotherapy drug cisplatin. Therefore, CASC2c may serve as a new biomarker and therapeutic target in the diagnosis and treatment of NSCLC.