Long non-coding RNA CASC2 suppresses the proliferation of gastric cancer cells by regulating the MAPK signaling pathway

Long non-coding RNAs (lncRNAs) have been shown to play important roles in tumorigenesis. However, the biological functions and molecular mechanisms underlying aberrantly expressed lncRNAs in gastric cancer (GC) is still unclear. In this study, a novel lncRNA CASC2 was chosen to evaluate the effect on GC cell growth and the possible mechanism. Our results showed that CASC2 was significantly downregulated in human GC tissues and cell lines by quantitative RT-PCR. Overexpression of CASC2 in GC cells significantly inhibited the cell growth in vitro and in vivo. We further found that MAPK pathway especially the ERK1/2 and JNK component were involved in the CASC2 mediated GC cell proliferation. Moreover, combination treatment of CASC2 overexpression and suppression ERK1/2 or JNK produced synergistic inhibitory effects in vitro. Thus, these results indicated that CASC2 might serve as a tumor suppressor lncRNA that suppressed cell proliferation by inactivation of MAPK pathway. These findings suggested that CASC2 could be a potential therapeutic target for the treatment of GC patients.