Long noncoding RNA KCNQ1OT1 contributes to tumor growth and activates Wnt/β-catenin signaling in osteosarcoma by targeting the miR-3666/KLF7 axis

Abstract

Osteosarcoma (OS) is a type of primary malignant cancer occurring in the bone and poses a threat to the lives of children and young adults. Long non-coding RNAs (lncRNAs) have been certified to play important roles in various human malignant tumors, including OS. lncRNA KCNQ1OT1 has been investigated in certain types of cancer; however, its role and molecular mechanisms in OS remain to be determined. In the present study, a high KCNQ1OT1 expression was detected in human OS tissues and cell lines. Moreover, patients with OS with a high expression of KCNQ1OT1 presented a worse prognosis. Loss-of-function assays demonstrated that KCNQ1OT1 silencing suppressed cell proliferative, migratory and invasive abilities in OS. Importantly, the knockdown of KCNQ1OT1 suppressed the Wnt/β-catenin signaling pathway in OS. In vivo assays displayed the inhibitory role of the silencing of KCNQ1OT1 in OS tumor growth. As regards the underlying mechanisms, KCNQ1OT1 could sponge miR-3666, and its expression was negatively associated with that of miR-3666 in OS tissues. Thereafter, Kruppel-like factor 7 (KLF7), upregulated in OS tissues and cells, was discerned as a target gene of miR-3666. Furthermore, KLF7 expression negatively correlated with miR-3666 expression, whereas it positively correlated with KCNQ1OT1 expression. A rescue assay delineated that the overexpression of KLF7 counteracted the KCNQ1OT1 knockdown-induced suppression of OS cell proliferation, migration, invasion and Wnt/β-catenin signaling. Collectively, the present study demonstrates that KCNQ1OT1 facilitates OS progression and activates Wnt/β-catenin signaling by targeting the miR-3666/KLF7 axis.