A negative regulation loop of long noncoding RNA HOTAIR and p53 in non-small-cell lung cancer.

Non-small-cell lung cancer (NSCLC) is one of the leading causes of cancer-related death worldwide, and the 5-year survival rate is still low despite advances in diagnosis and therapeutics. A long noncoding RNA (lncRNA) HOX antisense intergenic RNA (HOTAIR) has been revealed to play important roles in NSCLC carcinogenesis but the detailed mechanisms are still unclear. In the current study, we aimed to investigate the regulation between the lncRNA HOTAIR and p53 in the NSCLC patient samples and cell lines. Our results showed that HOTAIR expression was significantly higher in the cancer tissues than that in the adjacent normal tissue, and was negatively correlated with p53 functionality rather than expression. When p53 was overexpressed in A549 cells, the lncRNA HOTAIR expression was downregulated, and the cell proliferation rate and cell invasion capacity decreased as a consequence. We identified two binding sites of p53 on the promoter region of HOTAIR, where the p53 protein would bind to and suppress the HOTAIR mRNA transcription. Inversely, overexpression of lncRNA HOTAIR inhibited the expression of p53 in A549 cells. Mechanistic studies revealed that HOTAIR modified the promoter of p53 and enhanced histone H3 lysine 27 trimethylation (H3K27me3). These studies identified a specific negative regulation loop of lncRNA HOTAIR and p53 in NSCLC cells, which revealed a new understanding of tumorigenesis in p53 dysfunction NSCLC cells.