Formaldehyde inhibits proliferation of bronchial epithelial cells by down-regulating miR-375

Objective: To study the effect of formaldehyde on the proliferation of human bronchial epithelial cells 16HBE and to explore its mechanism. Methods: MTT assay was used to detect the inhibition rate of formaldehyde-treated 16HBE cells; FCOH + miR-375 group (transfected miR-375 mimics), FCOH + miR-con group (transfected miR-con), FCOH + si-KLF4 group (transfected si-KLF4) and FCOH + si-con group (transfected si-con), were transfected into 16HBE cells by liposome method, then treated with formaldehyde 200 μmol/L for 24 h; qRT-PCR was used to detect the expression of miR-375 in each group; the protein expression of KLF4 in each group was detected by Western blot. The fluorescence activity of each group was detected by dual-fluorescein gene detection assay. Results: Compared with 16HBE cells in Control group, the expression of miR-375 was significantly decreased in FCOH group, cell proliferation was significantly decreased, and KLF4 expression was significantly increased (p < .05). Overexpression of miR-375 and KLF4 knockdown could reverse the inhibition effect of formaldehyde on proliferation of 16HBE cells; KLF4 is a target of miR-375. KLF4 could reverse the promotion of miR-375 on the proliferation of formaldehyde-treated 16HBE cells. Conclusion: Formaldehyde can inhibit the proliferation of human bronchial epithelial cells. The mechanism may be related to the down-regulation of miR-375 targeting KLF4, which will provide support for the treatment of chronic respiratory diseases.