Down-Regulation of Ribosomal Protein RPS21 Inhibits Invasive Behavior of Osteosarcoma Cells Through the Inactivation of MAPK Pathway

Objective: The goal of our present study was to explore the expression level, biological function, and underlying molecular mechanism of ribosomal protein s21 (RPS21) in human osteosarcoma (OS). Methods: Firstly, we evaluated the expression of RPS21 in OS tissue samples based on the Gene Expression Omnibus (GEO) datasets and also measured the RPS21 expression of OS cell lines (MG63, and U2OS) by quantitative real-time polymerase chain reaction (qRT-PCR). siRNA interference method was used to reduce the expression of RSP21 in the OS cells. Cell Counting Kit-8 (CCK-8), colony formation, wound-healing, and transwell assays were conducted to measure the proliferation, migration, and invasion of OS cells. The mitogenactivated protein kinase (MAPK) pathway-related proteins levels were examined by Western blot. Results: Our analyses showed that the expression of RPS21 was significantly increased in OS, compared with normal samples. Upregulation of RPS21 was associated with worse outcomes of OS patients. Knockdown of RPS21 suppressed OS cell proliferation, colonyforming ability, migration, and invasion capacities. Moreover, down-regulation of RPS21 inactivated the MAPK signaling pathway. Conclusion: RPS21 plays an oncogenic candidate in OS development via regulating the activity of MAPK pathway; therefore, it may serve as a novel therapeutic target for OS treatment.