Objective: To examine the expressions of glyoxalase I (GLO-I) in endometrial cancer tissues and cell lines and to investigate the roles of GLO-I on proliferation and apoptosis in endometrial cancer cells.
Methods: Immunohistochemistry, western blot and RT-PCR were used to investigate the expressions of GLO-I protein and mRNA in endometrial cancer tissues and Ishikawa cell lines;enzyme activity of GLO-I in normal endometrium, endometrial cancer and paraneoplastic tissue samples was detected with spectrophotometer;proliferation and apoptosis of Ishikawa cell before and after RNA interference (RNAi) procedure were detected by the methyl thiazolyl tetrazolium (MTT) and flow cytometry, respectively.
Results: (1) There were significant differences of GLO-I expression between normal endometrium (0/19) and endometrial cancer tissues (76%, 22/29); these were also significant differences of enzyme activity of GLO-I among normal endometrium, paraneoplastic and endometrial cancer tissues (1.1, 0.8 vs 92.3 IU/mg; P < 0.01). Enzyme activity of GLO-I in fresh normal endometrium and paraneoplastic tissues was weak, while that of fresh endometrial cancer tissues was as high as 92.3 IU/mg in average. (2) The expression of GLO-I mRNA in Ishikawa cell transfected with GLO-I siRNA was significantly lower than that in negative group (0.25 ± 0.06 vs 0.93 ± 0.10, P < 0.01), and the similar results that in the expression of GLO-I protein (0.38 ± 0.06 vs 0.94 ± 0.13, P < 0.01). (3) Proliferation in Ishikawa cell was significantly inhibited after silencing RNA expression of GLO-I (P = 0.028). The apoptosis rate of cells transfected with GLO-I siRNA was significantly higher than that of negative control group and blank control group [(6.7 ± 0.8) % vs (1.2 ± 0.4)%, (1.4 ± 0.4)%; P < 0.01].
Conclusion: The expression and enzyme activity of GLO-I is significantly increased in endometrial cancer, which could promote abnormal proliferation and inhibit apoptosis in endometrial cancer cells.