Piperlongumine inhibits the progression of osteosarcoma by downregulating the SOCS3/JAK2/STAT3 pathway via miR-30d-5p.

Abstract Aims The present study evaluated the functions of Piperlongumine (PL) in osteosarcoma (OS) cell growth and metastasis both in vitro and in vivo. Main methods MTT assay was conducted to test the cytotoxic effects of PL on the human osteoblasts line HFOB1.19 and the human normal chondrocyte line C28/I2T. FITC-Annexin V and propidium iodide (PI) were used to examine cell apoptosis. The migration, invasion and relative epithelial-mesenchymal transition were examined by Transwell assay and Western blotting. Reverse transcription-quantitative PCR (RT-qPCR) was performed to analyze the cytokine signaling 3 (SOCS3) mRNA expression. TargetScan database was used to predict the target of SOCS3. The binding association between miR-30d-5p and SOCS3 in U2OS and MG63 cells was evaluated by the dual-luciferase reporter assay. A xenograft model was constructed to evaluate the effect of PL on OS cell growth in vivo. Key findings The results revealed that PL inhibited the growth, migration, invasion, epithelial-mesenchymal transition, and promoted the apoptosis of OS cells dose-dependently. In addition, PL upregulated the protein levels of suppressor of SOCS3, while it inactivated the JAK2/STAT3 pathway, which was accompanied by a decreased level of microRNA (miR)-30d-5p. Furthermore, SOCS3was confirmed as a novel target of miR-30d-5p. Overexpression of miR-30d-5p not only led to decreased expression of SOCS3, but also dampened the antitumor effect of PL on OS. Significance The present data demonstrated that PL inhibited the progression of OS via downregulation of the SOCS3-mediated JAK2/STAT3 pathway by inhibiting miR-30d-5p.