Overexpression of the non-coding SOX2OT variants 4 and 7 in lung tumors suggests an oncogenic role in lung cancer

Abstract

Despite the advances in cancer therapy, lung cancer still remains the most leading cause of cancer death worldwide. The long non-coding RNAs (lncRNAs) are recently introduced as novel regulators of human cancers. SOX2 overlapping transcript (SOX2OT) is a cancer-associated lncRNA gene that encodes different alternatively spliced transcripts. Here, we investigated the alterations in the preferential expression of different SOX2OTs in twenty non-small cell lung cancer (NSCLC) patients by real-time quantitative reverse transcription PCR (qRT-PCR) method. We observed preferential expression of SOX2OT4 and SOX2OT7 in lung tumor tissues. The quantitative gene expression analysis revealed that >30 % of NSCLC tumors express SOX2OT4 (mean = 7.6 times) and SOX2OT7 (mean = 5.9 times) more than normal tissues, with higher expression in squamous cell carcinoma. Further, we observed overexpression of pluripotency-associated transcription factor, SOX2 in 47 % of our samples concordant with SOX2OT (R = 0.62, P value <0.05). Overexpression of OCT4A gene was also observed in 36.8 % of tumor tissues. Then, we investigated the effects of SOX2OT suppression in lung adenocarcinoma cell line, by means of RNAi. Cell characteristics of colony formation, apoptosis, 2-D mobility, and cell cycle progression were measured in control and treated A549 cells. The SOX2OT knockdown significantly reduced the colony formation ability of cancer cells; however, no alterations in the rate of apoptosis were detected. On the other hand, SOX2OT-suppressed cells had elevated accumulation in G2/M phase of cell cycle and exhibited limited mobility. Altogether, our findings support a potential oncogenic role for SOX2OT in non-small cell lung cancer tumor genesis and SOX2OT seems a promising therapeutic candidate for NSCLC. © 2016, International Society of Oncology and BioMarkers (ISOBM)