Knockdown of autophagy-related protein 6, Beclin-1, decreases cell growth, invasion, and metastasis and has a positive effect on chemotherapy-induced cytotoxicity in osteosarcoma cells

Abstract Beclin-1, a well-known key regulator of autophagy, has been implicated in many disorders, including cancer, aging, and degenerative diseases. Previous studies demonstrated that Beclin-1 participated in tumorgenesis and was highly expressed in colorectal cancer cells, primary duodenal adenocarcinoma, and hepatocellular carcinoma cells, and overexpression of Beclin-1 could induce autophagic cell death in leukemia cells. However, the exact effects and molecular mechanisms of Beclin-1-mediated autophagy in osteosarcoma are still unknown up to now. Here, we evaluated the role of Beclin-1 in human osteosarcoma cell lines in vivo and in vitro. In order to characterize the endogenous expression of Beclin-1 in osteosarcoma cell lines, we performed real-time PCR and Western blot analysis. We further analyzed the level of Beclin-1 in osteosarcoma cells after chemotherapy and investigated the impact of autophagy inhibition on chemotherapy-induced cytotoxicity. We used the small interfering RNA (siRNA) directed against Beclin-1 to infect the osteosarcoma cell line with relatively high Belcin-1 expression. Furthermore, we determine the functional relevance of Beclin-1 knockdown to osteosarcoma cell growth, migration, and invasion, and investigate the expression levels of matrix metallopeptidase-2 (MMP-2), MMP-9, phosphoinositide 3-kinase p85α (PI3Kp85α), and phosphorylated AKT (p-AKT). As a result, HOS osteosarcoma cells exhibited higher Beclin-1 expression. An...
Source: Tumor Biology - Category: Cancer & Oncology Source Type: research