Long non-coding RNA PTCSC3 inhibits human oral cancer cell proliferation by inducing apoptosis and autophagy

IntroductionLong non-coding RNAs (lncRNAs) have gained increased attention due to the discovery of their roles in cancer-related processes. LncRNA PTCSC3 has been shown to have tumour-suppressive effects in thyroid cancer and glioblastoma. This study investigated the role of lncRNA PTSC3 in human oral cancer.Material and methodsCell viability was determined by MTT assay. The induction of apoptosis was confirmed by 4′,6-diamidino-2-phenylindole (DAPI) and Annexin V/PI assays. Ultrastructural analysis was performed by electron microscopy. Transwell assay was used to monitor the invasion of oral cancer cells.ResultsThe results revealed significant (p < 0.05) suppression of PTCSC3 expression in human oral cancer tissues and cell lines. The overexpression of PTCSC3 caused a significant (p < 0.05) decline in the proliferation of the human oral cancer cells via induction of apoptotic cell death which was accompanied by remarkable enhancement of Bax and suppression of Bcl-2. The electron microscopic analysis showed the development of autophagic vesicles in both the SCC-1 and SCC-9 cells indicative of autophagy. The western blotting analysis showed that PTCSC3 overexpression caused a remarkable increase in LC3B-I and Beclin 1 expression. PTCSC3 overexpression caused a significant (p < 0.05) decrease in invasion of the human SCC-1 and SCC-9 oral cancer cells. The invasion of the SCC-1 and SCC-9 cells was inhibited by 62% and 69% respectively.ConclusionsOverall, the evidence suggests that lncRNA PTCSC3 acts as a tumour suppressor in human oral cancer and suppresses oral cancer proliferation via induction of apoptosis and autophagy.