OBJECTIVETo investigate the effect of a common polymorphism rs928508(A/G) in flanking region of miR-30c on the expression of pri, pre and mature miR-30c, and discuss the effect of this polymorphism on the maturing process of miR-30c in lung carcinoma.

METHODSThe pGL3-promoter-miR-30c-A and pGL3-promoter-miR-30c-G luciferase plasmids were created containing A or G allele of miR-30c flanking region. Taqman assay was used to genotype rs928508 polymorphism in 50 lung cancer tissues. RT-PCR was performed to determine the expression of pri-miR-30c, pre-miR-30c, mature miR-30c and miR-30c host gene NFYC in the 50 lung cancer tissues.

RESULTSThe luciferase expression level of the pGL3-promoter-miR-30c-A construct group was not significantly different compared with that in the the pGL3-promoter-miR-30c-G construct group (A549 cells, P = 0.758; 293A cells, P = 0.554; CHO cells, P = 0.175). The results demonstrated that rs928508(A/G) variant had no effect on the transcriptional regulation of pri-miR-30c. In the genotype-phenotype collection analysis of the 50 lung cancer tissues, the expression of pre-miR-30c and mature miR-30c for rs928508 AG/GG genotypes showed significantly lower levels compared with those in the AA genotype (P = 0.009, P = 0.011). However, the expression of pri-miR-30c showed no significant difference between AG/GG genotypes and AA genotype. Similarly, the expression of host NFYC gene was correlated with pri-miR-30c, showed no significant difference between AG/GG genotypes and AA genotype.

CONCLUSIONThe rs928508(A/G) polymorphism in flanking region of miR-30c could influence the processing from pri-miR-30c to mature miR-30c, but does not influence the transcription of pri-miR-30c.