BRAF-activated long non-coding RNA contributes to cell proliferation and activates autophagy in papillary thyroid carcinoma

Long non-coding RNAs (lncRNAs) are novel regulators in cancer biology. BRAF-activated lncRNA (BANCR) is overexpressed in melanoma and has a potential functional role in melanoma cell migration. However, little is known about the role of BANCR in the development of papillary thyroid carcinoma (PTC). In the present study, BANCR expression was examined in six pairs of PTC and matched adjacent normal tissues. The results revealed that BANCR levels were significantly higher in the PTC tissues and PTC IHH-4 cells compared with the normal controls. Knockdown of BANCR in the IHH-4 cells inhibited proliferation and increased apoptosis of the cells in vitro. Further investigation of the underlying mechanisms revealed that BANCR markedly activated autophagy. Overexpression of BANCR inhibited apoptosis in the IHH-4 cells, whereas inhibition of autophagy stimulated apoptosis in the BANCR-overexpressed cells. BANCR overexpression also increased cell proliferation and the inhibition of autophagy abrogated BANCR overexpression-induced cell proliferation. In addition, the overexpression of BANCR resulted in an increase in the ratio of LC3-II/LC3-I, a marker for autophagy, while the knockdown of BANCR decreased the ratio of LC3-II/LC3-I. These results revealed that BANCR expression levels are upregulated in PTC. Additionally, BANCR increases PTC cell proliferation, which could activate autophagy.