Mechanism of oxymatrine promoting the apoptosis of osteosarcoma MG63 cell line through mitophagy mediated by COX-2/PINK1/Parkin signaling pathway / 中国药房

ABSTRACT

OBJECTIVE To study the mechanism of oxymatrine inducing apoptosis of osteosarcoma MG63 cell line based on mitophagy mediated by cyclooxygenase-2 （COX-2）/PTEN-induced putative kinase-1 （PINK1）/Parkinson disease protein-2 （Parkin） signaling pathway. METHODS MG63 cells were treated with 2.0， 4.0， 8.0 mg/mL oxymatrine and 6 μmol/L 5-fluorouracil， then the apoptotic rate， the expression of apoptosis-related proteins [B-cell lymphoma-2 （Bcl-2）， Bcl-2 related X protein （Bax）]， the proportion of decrease in mitochondrial membrane potential， the level of mitophagy as well as the protein expressions of PINK1， Parkin， and microtubule-associated protein 1 light chain-3Ⅱ （LC3-Ⅱ） were detected. PINK1 small interfering RNA （siRNA） was adopted to intervene in the expression of PINK1， the cells were divided into control group， PINK1 siRNA group， oxymatrine group， and PINK1 siRNA+oxymatrine group； the protein expressions of PINK1， Parkin， and LC3-Ⅱ， the proportion of decrease in mitochondrial membrane potential （MMP） as well as apoptotic rate were detected. The lentivirus infection technique was used to overexpress COX-2， the cells were divided into control group， oxymatrine group， COX-2 group， and COX-2+oxymatrine group. The protein expressions of COX-2， PINK1， and Parkin， as well as the proportion of decrease in MMP were detected. RESULTS After being treated with oxymatrine， the apoptotic rate， the protein expressions of Bax， PINK1， Parkin， and LC3-Ⅱ， the level of mitophagy as well as the proportion of decrease in MMP were significantly increased （P＜0.05）， while the protein expression of Bcl-2 was significantly decreased （P＜0.05）. Compared with the oxymatrine group， the protein expressions of PINK1， Parkin， and LC3-Ⅱ， apoptotic rate and the proportion of decrease in MMP were significantly decreased in PINK1 siRNA+oxymatrine group （P＜0.05）. Compared with the oxymatrine group， the protein expression of COX-2 in the COX-2+oxymatrine group was increased significantly （P＜0.05）， while the protein expressions of PINK1 and Parkin as well as the proportion of 526087266@qq.com decrease in MMP were decreased significantly （P＜0.05）. CONCLUSIONS Oxymatrine can mediate the overactivity of mitophagy based on the PINK1/Parkin signaling pathway by inhibiting COX-2 expression， thus promoting the apoptosis of the MG63 osteosarcoma cell line.