Lentivirus-mediated silencing of MPHOSPH8 inhibits MTC proliferation and enhances apoptosis.

Thyroid carcinoma (TC) is the most common malignancy of the endocrine organs, and its incidence rate has steadily increased over the last decade. For medullary thyroid cancer (MTC), a type of TC, a high mortality rate has been reported. In previous studies, M-phase phosphoprotein 8 (MPHOSPH8) displayed an elevated expression in various human carcinoma cells. Thus, MPHOSPH8 may be a sensitive biomarker that could be used for the diagnosis and follow-up of MTC. In the present study, plasmids of RNA interference targeting the MPHOSPH8 gene were constructed. Once these lentiviruses targeting MPHOSPH8 were transfected into the MTC cell line TT, cell viability and proliferation were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry was used to assess the cell cycle distribution and apoptosis. The expression levels of MPHOSPH8 were detected by reverse transcription quantitative-polymerase chain reaction and western blot analyses. Depletion of MPHOSPH8 significantly inhibited cell proliferation. Furthermore, knockdown of MPHOSPH8 in TT cells led to G0/G1 phase cell cycle arrest and apoptosis. The results of the present study suggest that MPHOSPH8 promotes cell proliferation and may be a potential target for anticancer therapy of MTC.