Restoration of microRNA-212 causes a G0/G1 cell cycle arrest and apoptosis in adult T-cell leukemia/lymphoma cells by repressing CCND3 expression.

Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive T-cell malignancy. This study was designed to explore the expression and functional significance of microRNA (miR)-212 in ATL. The expression of miR-212 in human ATL tissues and cell lines were investigated. Gain-of-function experiments were carried out to determine the roles of miR-212 in cell proliferation, tumorigenesis, cell cycle progression, and apoptosis. We also identified and functionally characterized the target genes of miR-212 in ATL cells. Compared with normal lymph node biopsies, lymphoma samples from ATL patients displayed underexpression of miR-212 (p=0.0032). Consistently, miR-212 was downregulated in human ATL cell lines, compared with normal T lymphocytes. Restoration of miR-212 significantly (p