Regulation of miR-125a expression by rs12976445 single-nucleotide polymorphism is associated with radiotherapy-induced pneumonitis in lung carcinoma patients.

ABSTRACT

BACKGROUND: The expression of miR-125 is regulated by an single-nucleotide polymorphism (SNP), rs12976445, which may be involved in the risk of pneumonitis among non-small-cell lung carcinoma patients undergoing the radiotherapy. We investigated this hypothesis via clinical data analysis and in vitro experiments. METHODS: An online microRNA (miRNA) database (www.mirdb.org) and luciferase reporter assays were used to confirm the role of transforming growth factor-ß1 (TGFB1) as a target gene of miR-125a. Quantification by real-time PCR and Western blot analysis were used to measure the expression of miRNA-125a and TGFB1 among different groups (carrying CC, CT, and TT genotypes of rs12976445) or cells transfected with a scramble control, miR-125a mimics, TGFB1 siRNA, or miR-125a inhibitors. RESULTS: We evaluated 699 NSCLC patients and found that the patients carrying the TT or CT genotype of rs12976445 had a higher risk of radiotherapy-induced pneumonitis. Computational analysis and luciferase assays validated that TGFB1 is a target gene of miR-125a. The expression level of miR-125a mRNA was significantly downregulated in the CT and TT groups, while the expression levels of TGFB1 and SMAD2 were significantly upregulated in the CC group. The expression of TGFB1 and SMAD2 was regulated by miR-125a in A549 cells. CONCLUSION: The rs12976445 SNP in miR-125a is associated with the risk of pneumonitis after in lung cancer patients undergoing the radiotherapy by regulating the expression of miR-125a and TGFB1.