Long noncoding RNA MALAT1 promotes uveal melanoma cell growth and invasion by silencing of miR-140.

Increasing evidences have demonstrated that long noncoding RNAs (LncRNAs) play a significant role in the development of tumor. However, the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in uveal melanoma remains unknown. In this study, we demonstrated that the expression of MALAT1 was upregulated in the uveal melanoma tissues compared to normal tissues. Among them, MALAT1 was upregulated in 72% (18/25) uveal melanoma tissues compared to their paired normal tissues. Knockdown of MALAT1 suppressed uveal melanoma cell proliferation, colony information, invasion and migration. Moreover, we showed that knockdown of MALAT1 promoted miR-140 expression and suppressed Slug and ADAM10 expression in the MUM-2C cell. In addition, we demonstrated that miR-140 was downregulated in the uveal melanoma tissues compared to normal tissues and cell lines. The expression level of MALAT1 was inversely correlated with the expression level of miR-140 in uveal melanoma tissues. These results suggested that MALAT1 served as an oncogenic LncRNA in the development of uveal melanoma.