Background: The fragile histidine triad (FHIT) gene is abnormally expressed in many kinds of tumors and plays an important role in tumor development. However, the function of the FHIT gene in muco-epidermoid carcinoma (MEC) is still unknown. This study aimed to investigate the effect of exogenous FHIT gene on the biologic properties of MEC cells.
Methods: Wild-type FHIT gene was transferred into MEC-1 cells. The in vitro proliferation, clone formation ability and apoptosis of FHIT-transfected MEC-1 cells (MEC-FHITc4) were examined by cell counting, clonal forming assay, immunochemical staining, histochemical staining, flow cytometry analysis and transmission electron microscopy. The tumorigenicity of MEC-FHITc4 cells was observed by in vivo study in nude mice.
Results: In vitro study showed that the population doubling times of MEC-1 and MEC-FHITc4 cells were 21.03 h and 26.86 h, respectively. FHIT gene transfer reduced the percentage of cells in cell cycle S phase (3.8%) and kept more cells in the G(1) phase (62.4%). Additionally, the clonal forming rates of MEC-1 and MEC-FHITc4 were 17.9+/-0.87% and 12.3+/-0.02%, respectively. In a 4-week tumor growth study in nude mice, FHIT transfection suppressed the tumor growth by 70.1+/-0.38%. Interestingly, MEC-FHITc4 cells were stained more strongly with Alician Blue and Periodic Schiffs than control cells.
Discussion: The FHIT gene might function to inhibit the proliferation and tumorigenicity of MEC-1 cells, and to induce the differentiation of MEC-1 cells, in vitro and in vivo.