Abstract:
Objective To investigate the effect and mechanism of miR-185-5p on proliferation and apoptosis of oral squamous cell carcinoma (OSCC) cells.
Methods qRT-PCR kit was used to detect the expression of miR-185-5p and insulin-like growth factor binding protein 2 (IGFBP2) in 72 patients with OSCC, as well as in normal human oral keratinocytes Hok, oral squamous cell carcinoma cells SCC-15, HSC-3 and Cal-27. NC group (without any treatment), agomiRNA group (transfected agomiRNA), agomiR-185-5p group (transfected with agomiR-185-5p), si-NC group (transfected with si-NC), si-IGFBP2 group (transfected si-IGFBP2), agomiR-185-5p pcDNA group (co-transfected agomiR-185-5p and pcDNA), agomiR-185-5p + pcdna-IGFBP2 group (co-transfected agomiR-185-5p and pcDNA-IGFBP2) were transfected into SCC-15 cells by liposome method. Cell counting Kit (CCK8), clone formation test and 5-ethynyl-2 ′- deoxyuridine (EDU) staining were used to detect the proliferation of cells. Apoptosis was detected by flow cytometry. IGFBP2 protein was detected by western blot (WB). The binding of miR-185-5p to IGFBP2 was detected by double luciferase report assay.
Results Compared with adjacent tissues, the expression of miR-185-5p decreased and IGFBP2 increased in cancer tissues (stage Ⅰ - Ⅱ, stage Ⅲ and stage Ⅳ) (r = –0.412, P < 0.05). The high expression of miR-185-5p indicated an increase in the 3-year overall survival rate of patients. Compared with HOK group, the expression of miR-185-5p decreased in SCC-15, HSC-3 and Cal-27 groups, meanwhile the activity, clone formation rate and EDU positive rate of SCC-15 cells overexpressing miR-185-5p decreased, the apoptosis rate increased (P < 0.05). Knockdown of IGFBP2 had a similar effect. miR-185-5p targeted IGFBP2 and negatively regulated IGFBP2. Overexpression of IGFBP2 partially reversed the proliferation inhibition and apoptosis promotion of SCC-15 cells by miR-185-5p.
Conclusion miR-185-5p is low expressed in OSCC. Overexpression of miR-185-5p can inhibit the proliferation of OSCC cells, promote apoptosis and predict the prognosis of patients, which is related to targeting IGFBP2.