MiR-21 promotes pterygium cell proliferation through the PTEN/AKT pathway

PURPOSE: To evaluate the effect of the overexpression of miR-21 on the properties of pterygium and examine whether miR-21 promotes the proliferation of pterygium cells through targeting the PTEN/AKT signaling pathway. METHODS: Information regarding patient gender, age, and pterygium severity was gathered. Expression of miR-21 was obtained through examination of excised pterygium tissues and superior conjunctiva tissues with real-time PCR. Human pterygium fibroblasts (HPFs) were obtained from pterygium surgery and subjected to primary culture. The HPF cell lines were divided into a negative control group, an miR-21 inhibitor group, and an miR-21 inhibitor + VO-Ohpic trihydrate group, and then the cell viability and apoptosis and the expression of PTEN and AKT were examined. RESULTS: Fifty-eight subjects with unilateral primary pterygium were included. An increase in the miR-21 levels in pterygium tissue was evident compared with that in the paired normal conjunctival tissues (independent-samples t test, p<0.01). As the severity of the pterygium increased, the miR-21 levels increased (p=0.004, rs=0.373, Spearman’s rank correlation coefficient). The miR-21 inhibitor suppressed the proliferation and induced apoptosis of HPF cells through increasing the PTEN expression, and further decreasing the expression of p-AKT, which could be reversed by the PTEN inhibitor VO-Ohpic trihydrate. CONCLUSIONS: Aberrant miR-21 overexpression in the pterygium could target PTEN, which contributes to abnormal proliferation of the HPF cells through depressing the PTEN/AKT pathway. The results also suggested the potential of miR-21 and the PTEN/AKT pathway as a novel therapeutic strategy for pterygium.