Regulation of long non-coding RNAs XIST and ROR induced by homeodomain protein TGIF2LX in colorectal cancer.

Background: Homeodomain protein transforming growth factor beta-induced factor 2 like, X-linked (TGIF2 LX) has been demonstrated to act as a transcription factor and regulate cancer cell proliferation. Long non-coding RNAs (lncRNAs) are well known as molecular regulators of colorectal cancer (CRC). Our aim was to evaluate the clinical and biological significance of TGIF2 LX and its effect on lncRNAs regulator of reprogramming (ROR) and X-inactive specific transcript (XIST) expression in CRC cells. Materials and Methods: Thirty-six CRC tissues and 22 adjacent normal colorectal tissues were subjected to RNA extraction and analysis of TGIF2 LX gene expression by quantitative real-time polymerase chain reaction (qRT-PCR). The human SW1116 cell line was transfected with cDNA for the TGIF2 LX gene. Microscopic analysis, reverse transcriptase PCR, and western blotting were used for confirming at transcriptional and translational levels. Methyl thiazolyl tetrazolium and colony formation assays were applied for evaluating the in vitro cell viability and colony-forming ability, respectively. LncRNA expression analysis was carried out using qRT-PCR. Results: The results showed that the expression levels of TGIF2 LX were significantly downregulated in CRC tissues compared to adjacent normal tissues (P = 0.032). Furthermore, the overexpression of TGIF2 LX could reduce the CRC cell line proliferation. The gene expression analysis revealed a significantly reduced level of lncRNA ROR and lncRNA XIST in TGIF2 LX-transfected SW1116 cells compared to nontransfected cells. Conclusion: Our findings provided evidence of molecular mechanisms by which TGIF2 LX may interact with lncRNAs ROR and XSIST to regulate CRC development by acting as a tumor suppressor. Thus, this protein may potentially be a promising option for CRC gene-based therapeutic strategies. [ABSTRACT FROM AUTHOR]