Effects of melittin on the cell cycle of bladder cancer cell line T24 and its mechanism

Abstract

Objective To investigate the effects of melittin on the cell cycle of bladder cancer cell line T24 and the related regulatory mechanisms.Methods In vitro cultured bladder cancer T24 cells were treated with melittin (0,7.5,10.0,and 12.5 mg/L).Flow cytometry was applied to examine the cell cycle of T24 cells.Western blotting method was applied to detect the protein expression of Cyclin A,cyclindependent kinase 2 (CDK2),CDK inhibitor p21 cip1 and cyclin dependent kinase inhibitor protein 27 (p27kip1).Results Corresponding to different concentration groups of melittin,the proportion of T24 cells in S phase was (25.73 ±2.11)％,(31.57 ±1.91)％,(45.37±0.74)％,and (53.67±1.12)％,showing significant difference between melittin-treated groups and control group (P ＜ 0.01).The protein expression of p21cip1 and p27kip1 in melittin-treated T24 cells was increased (p21cip1:0.156 1 ±0.011 6,0.209 2 ±0.010 8,0.287 9 ±0.012 9,0.351 8 ±0.013 0;p27kip1:0.250 3 ±0.012 3,0.342 1 ±0.012 3,0.400 3 ±0.009 9,0.469 2 ±0.013 0),while that of Cyclin A and CDK2 significantly decreased as compared with control group (Cyclin A:0.950 7 ± 0.017 8,0.870 6 ± 0.011 9,0.806 5 ± 0.012 0,0.726 7 ± 0.018 4;CDK2:0.965 4 ±0.014 5,0.868 3 ±0.015 3,0.755 4 ±0.008 5,0.652 6 ±0.018 3,P ＜0.01).Conclusion Melittin can cause S phase arrest of T24 cells,which may be associated with the down-regulation of Cyclin A and CDK2 expression while up-regulation of p21cip1 and p27kip1. Key words: Bladder neoplasm; Melittin; Cell cycle