LncRNA LINC-PINT Inhibits Cancer Cell Proliferation, Invasion, and Migration in Osteosarcoma by Downregulating miRNA-21.

Downregulation of LncRNA LINC-PINT has been observed in different types of cancer cells, indicating its role as a tumor suppressor. Expression of LINC-PINT and miRNA-21 in tumor tissues and adjacent healthy tissues of 56 patients with osteosarcoma was detected by real-time quantitative PCR. Correlations between expression levels of LncRNA LINC-PINT and miRNA-21 were analyzed by Pearson's correlation coefficient. In this study, we found that LncRNA LINC-PINT was inhibited, whereas miRNA-21 was promoted in tumor tissues than in adjacent healthy tissues of patients with osteosarcoma. Expression levels of LncRNA LINC-PINT were affected by both tumor size and tumor metastasis. LncRNA LINC-PINT and miRNA-21 were significantly and reversely correlated in both tumor cells and adjacent healthy tissues. LncRNA LINC-PINT overexpression led to downregulated miRNA-21 expression in cancer cells, whereas miRNA-21 overexpression did not significantly affect LINC-PINT expression. Overexpression of LncRNA LINC-PINT inhibited whereas miRNA-21 overexpression promoted cancer cell proliferation, migration, and invasion. In addition, miRNA-21 overexpression partially rescued the inhibited cell proliferation, migration, and invasion mediated by LncRNA LINC-PINT overexpression. Therefore, LncRNA LINC-PINT may inhibit cancer cell proliferation, invasion, and migration in osteosarcoma by downregulating miRNA-21.