SETD2 is a histone methyltransferase that catalyzes the trimethylation of lysine 36 on histone 3. SETD2 is frequently found to be mutated or deleted in a variety of human tumors, whereas the role of SETD2 in oncogenesis of osteosarcoma has never been defined. Here in our study, we uncovered that SETD2 regulates tumor growth and chemosensitivity of osteosarcoma. Overexpression of SETD2 significantly inhibited osteosarcoma cell growth in vitro and in vivo. Moreover, SETD2 significantly enhanced cisplatin-induced apoptosis in osteosarcoma cells and inhibited cancer stem cell properties in OS cells. SETD2 regulates Wnt/beta-catenin signaling and its downstream gene c-myc, CD133 and cyclin Dl. We further revealed that SETD2 upregulates H3K36me3 modification in GSK3B loci and promotes its transcription, which lead to beta-catenin degradation. Together, our study delineates SETD2 function in osteosarcoma as an important regulator of Wnt/beta-catenin signaling, and suggests SETD2 as a novel target in diagnosis and combined chemotherapy of osteosarcoma. (C) 2018 Published by Elsevier Inc.