[Effect of miR-542-3p on carcinogenesis induced by anti-benzo(a) pyrene-7,8-diol-9,10-epoxide]

To explore the effect of miR-542-3p in malignant transformation of human bronchial epithelial cells (16HBE) induced by anti-benzo(a)pyrene-7,8-diol-9,10-epoxide (anti-BPDE).

The relative expression level of mature miR-542-3p in transformed cells (16HBE-T) and untransformed control cells (16HBE-N) was measured by real-time quantitative polymerase chain reaction (qRT-PCR). miRNA mimic was transiently transfected into 16HBE-T to change the expression level of miR-542-3p, and then the influenced changes of cell proliferation, cell cycle, apoptosis, and soft agar colony formation rate and the migration of transfected cells were analyzed.

Before transfection, the expression level of mature miR-542-3p in 16HBE-T was lower (39.08 ± 6.95)% than it in 16HBE-N (t = 15.18, P < 0.05). In comparison with the 16HBE-T group, the expression level of miR-542-3p in miR-542-3p mimic-transfected group was (5.23 ± 0.55) fold (t = 17.37, P < 0.05) after transfection. Cell proliferation of mimic-transfected group was decreased to (62.06 ± 5.61)% (t = -17.28, P < 0.05), percentage of cells in G(0)/G(1) phase up to (74.76 ± 4.86)% (t = 4.53, P < 0.05), rate of colony formation degrade to (5.87 ± 0.67)% (t = -6.66, P < 0.05), coverage areas ratio decreased to (0.31 ± 0.08) (t = -6.78, P < 0.05). There was no change with apoptosis.

Our studies showed that miR-542-3p played the role as a tumor suppressor, which led to a significant decrease in the proliferation capacity and degree of malignancy. These findings suggest aberrantly down-regulated miR-542-3p may be one critical factor that contributes to malignant transformation of 16HBE induced by anti-BPDE.