Abstract: Objective To explore the expression level of miR-539 in endometrial stromal cells (ESCs) of endometrium in patients with endometriosis (EM), and the effects of miR-539 targeting matrix metalloproteinase 9 (MMP-9) on the invasion and migration of ESCs. Methods The endometrial samples of 60 EM patients and 47 non-EM patients admitted to Hubei Province Maternal and Child Health Hospital from 2016 to 2020 were collected. The ESCs were isolated for primary culture. The expression levels of miR-539 and MMP-9 mRNA were detected with qPCR technology, and its targeting relationship was detected with dual luciferase reporter gene. ESCs were transfected with Lipofectamine 3000 reagent and divided into the miR-539 mimics group, the mimics NC group, the miR-539 inhibitor group and the inhibitor NC group. CCK-8 was used to detect cell proliferation in each group. Scratch test was used to detect cell migration. Transwell was used to detect cell invasion. Western blot method was used to detect the expression levels of MMP-9 protein in each group of cells. Results The level of miR-539 mRNA in endometrium was significantly lower in the EM group than that of the control group (P＜0.05), and the level of MMP-9 mRNA was significantly higher than that of the control group (P＜0.05). The results of double luciferase report showed that miR-539 had an obvious targeting relationship with MMP-9 (P＜0.05). Compared with the mimics NC group, the ESCs cell proliferation, scratch healing rate, number of invasive cells and MMP-9 protein level were significantly reduced in the miR-539 mimics group (P＜0.05). Compared with the inhibitor NC group, the ESCs cell proliferation, scratch healing rate, number of invaded cells and MMP-9 protein level were significantly increased in the miR-539 inhibitor group (P＜0.05). Conclusion MiR-539 can target and regulate the expression level of MMP-9 and affect the cell proliferation, migration and invasion abilities of ESCs.

Key words: endometriosis, matrix metalloproteinase 9, cell movement, neoplasm invasiveness, microRNAs, endometrial stromal cells, miR-539, migration and invasion