Knockdown of microRNA-181a inhibits osteosarcoma cells growth and invasion through triggering NLRP3-dependent pyroptosis.

Abstract

This study aimed to investigate the physiological function and molecular mechanism of microRNA-181a (miRNA-181a) in the carcinogenesis of osteosarcoma. The relative expression of miRNA-181a in tissues and cultured cells was detected by quantitative real time-polymerase chain reaction (qRT-PCR). MiR-181a inhibitor and miR-181a mimics were used to manipulate its level in cells. Cell proliferation and invasion were measured using Cell Counting Kit-8 (CCK-8) assay and transwell assay, respectively. The protein levels of the targeted genes were detected by Western blotting and immunohistochemistry. Terminal Deoxynucleotidyl Transferase (TdT)-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to detect cell apoptosis. Moreover, a xenograft tumor bearing mice model was used to evaluate the effect of miR-181a in vivo. We found that miRNA-181a was aberrantly elevated in osteosarcoma tissues and cells. Moreover, the overexpression of miRNA-181a could facilitate cell proliferation and migration. By contrast, miRNA-181a knockdown reverses these effects. Additionally, downregulation of miRNA-181a could activate NOD-like receptor protein 3 (NLRP3)-dependent pyroptosis, as evidenced by the increase of pyroptosis-related genes (NLRP3, caspase-1, interleukin-18, and interleukin-1β) in miRNA-181a inhibitor transfected cells compared with the control. Further mechanistic studies identified that miRNA-181a knockdown suppresses cell proliferation and invasion by activating NLRP3-dependent pyroptosis. Silencing NLRP3 could effectively reverse the effects mediated by miRNA-181a inhibitor. Consistently, in vitro results also demonstrated that blockade of miRNA-181a notably suppresses tumor growth via activating pyroptosis. These results provide that miRNA-181a might serve as potential therapeutic target for osteosarcoma patients.