[Forkhead domain inhibitor-6 (FDI-6) increases apoptosis and inhibits invasion and migration of laryngeal carcinoma cells by down-regulating nuclear FoxM1].

Objective To study the effects of new small molecular inhibitor, forkhead domain inhibitor-6 (FDI-6), on proliferation, apoptosis, invasion and migration in human laryngeal carcinoma Hep-2 cell line and the related mechanism. Methods MTT assay was used to test the proliferation rate of Hep-2 cells before and 12, 24 hours after treated with (5, 10, 20, 40, 80) μmol/L of FDI-6. Flow cytometry (FCM) and Transwell chamber assay were respectively carried out to detect the apoptosis rate, cell invasion and migration in Hep-2 cells after treated by 10, 20 μmol/L FDI-6 for 24 hours. Real-time quantitative PCR (qRT-PCR) and Western blotting were performed to determine the mRNA and protein levels of FoxM1, Bcl-2 and BAX, respectively. Results Cell proliferation rate was inhibited by FDI-6 in a dose- and time-dependent manner. Twenty-four hours after 10, 20 μmol/L FDI-6 treatment, the apoptosis rate in Hep-2 cells was elevated and the ability of cell invasion and migration was inhibited in a dose-dependent manner. The qRT-PCR showed that there was no significant change in FoxM1 mRNA expression with or without FDI-6 treatment. Western blotting showed that the total protein level of FoxM1 was not obviously changed, but Bcl-2 was down-regulated, BAX was up-regulated. However, in the nuclear FoxM1 protein level decreased along with the ascent of FDI-6 concentration. Conclusion FDI-6 could induce cell apoptosis and inhibit cell proliferation, invasion and migration in Hep-2 cells. This may be related to the down-regulation of FoxM1 in the nucleus.