Long noncoding RNAs (lncRNAs) play crucial roles in tumor development of osteosarcoma (OS). LncRNA PCAT6 was involved in the progression of multiple human cancers. However, the biological function of PCAT6 in OS remains largely unknown. We found that PCAT6 was elevated in OS tissues relative to that in their adjacent normal tissues. The upregulation of PCAT6 was positively associated with metastasis status and advanced stages and predicted poor overall and progression-free survivals in patients with OS. Functionally, silencing PCAT6 inhibited the proliferation, migration and invasion abilities of OS cells. Mechanistically, PCAT6, acting as a competitive endogenous RNA, upregulated expression of TGFBR1 and TGFBR2 to activate TGF-beta pathway via sponging miR-185-5p. This study uncovers a novel underlying molecular mechanism of PCAT6-miR-185-5p-TGFBR1/2-TGF-beta signaling axis in promoting tumor progression in OS, which indicates that PCAT6 may serve as a promising prognostic factor and therapeutic target again OS. (C) 2019 Elsevier Inc. All rights reserved.