Suppression of long noncoding RNA MALAT1 inhibits the development of uveal melanoma via microRNA-608-mediated inhibition of HOXC4.

This study explored the effects of the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on the development of uveal melanoma. Moreover, the role of the MALAT1/microRNA-608 (miR-608)/homeobox C4 (HOXC4) axis was assessed by evaluating the proliferation, invasion, and migration, as well as the cell cycle distribution of uveal melanoma in vitro after knocking down MALAT1 or HOXC4 and/or overexpression of miR-608 in uveal melanoma cells (MUM-2B and C918). Moreover, the effects of the MALAT1/miR-608/HOXC4 axis in uveal melanoma in vivo were further evaluated by injecting the C918 cells into the NOD/SCID mice. HOXC4 was found to be a gene upregulated in uveal melanoma, while knockdown of its expression resulted in suppression of uveal melanoma cell migration, proliferation, and invasion, as well as cell cycle progression. In addition, the upregulation of miR-608 reduced the expression of HOXC4 in the uveal melanoma cells, which was rescued by overexpression of MALAT1. Hence, MALAT1 could upregulate the HOXC4 by binding to miR-608. The suppressed progression of uveal melanoma in vitro by miR-608 was rescued by overexpression of MALAT1. Additionally, in vivo assays demonstrated that downregulation of MALAT1 could suppress tumor growth through downregulation of HOXC4 expression via increasing miR-608 in uveal melanoma. In summary, MALAT1 downregulation functions to restrain the development of uveal melanoma via miR-608-mediated inhibition of HOXC4.