[Effects of gossypol acetic acid on the proliferation and methylation level of the human MutL homologue 1 gene in human tongue carcinoma cell line Tca8113].

OBJECTIVE: This paper aims to study the effects of gossypol acetic acid (GAA) on proliferation and methylation level of human MutL homologue 1 (hMLH1) gene in human tongue cancer cell line Tca8113. METHODS: The MTT assay was used to determine the effects of the acid on the proliferation inhibition in Tca8113 cells treated with different GAA concentrations. Nested methylation-specific polymerase chain reaction (nMSP) was used to detect the change in the methylation level of hMLH1 after 48 and 72 h with 30 and 15 micro mol L(-1) GAA treatment. RESULTS: MTT assay results showed the growth and proliferation inhibition of Tca8113 cells in the experimental GAA group after 24 h to 72 h of GAA treatment. The nMSP results indicated that the average optical density of hMLH1 in the Tca8113 cells significantly changed after the GAA treatment (30 micro mol L(-1) GAA for 48 h and 15 micro mol L(-1) for 72 h) (P<0.05) compared with that of the control group. CONCLUSION: GAA does not only inhibit Tca8113 proliferation but also has a demethylation effect on the hMLH1 gene. These phenomena may be part of an underlying tumor-suppression mechanism of GAA.