miR-448 downregulates MPPED2 to promote cancer proliferation and inhibit apoptosis in oral squamous cell carcinoma.

The incidence of oral squamous cell carcinoma (OSCC) is continuously increasing while its survival rate has not notably improved. There is a pressing need for improved understanding of the genetic regulation of OSCC tumorigenesis and progression. In this study, the function of miR-448 in the regulation of OSCC growth and its putative target were thoroughly analyzed in vitro. The expression of miR-448 was detected in human OSCC specimens and OSCC cell lines (Cal-27 and Scc-9) by reverse transcription-quantitative polymerase chain reaction. The function of miR-448 was investigated in Cal-27 cells transfected with miR-448 inhibitor, and its putative target determined using a luciferase reporter assay. MTT and wound healing assays and flow cytometry were used to evaluate the effects of miR-448 on OSCC proliferation, metastasis and apoptosis. The level of miR-448 was significantly elevated in human OSCC tissues and the Cal-27 cell line. Suppression of miR-448 expression attenuated cell proliferation and migration, and induced apoptosis of Cal-27 cells. Furthermore, miR-448 bound with the 3'-untranslated region of metallophosphoesterase domain containing 2 (MPPED2) mRNA, thereby reducing the MPPED2 protein level. Thus, it appears that miR-448 acts as a tumor inducer, causing OSCC growth by inhibiting the expression of its target MPPED2. These results demonstrate that miR-448 plays a critical role in OSCC tumorigenesis, and is a potential therapeutic target.