Establishment of cisplatin-resistant human bladder cancer cell line and investigation of its resistant mechanism

Objective To establish the cisplatin (CDDP)-resistant cell line from human bladder cancer cell line T24 and to investigate its resistant mechanism to CDDP. Methods A CDDP-resistant bladder cancer cell line T24/CDDP was established by gradually increasing dose of cisplatin and high-dose stimulation.The IC50and resistance index were estimated with cell counting Kit-8 (CCK-8). Cell growth curve, doubling time, and cell cycle phase distribution were measured. The expressions of protein kinase Cα(PKCα) and P- glycoprotein (P-gp) of T24 cells and T24/CDDP cells were measured with Western blot. Results The CDDP-resistant cell line T24/CDDP was established after 11 months, with a stable resistance to cisplatin and a resistant index of 4.17. The doubling time of T24 cells and T24/CDDP cells was(33.61±0.41)h and (39.94±0.63) h, with a significant difference (t=14.59, P=0.00). Compared to the S phase of T24 cells[(30.63±2.74)%], the S-phase of T24/CDDP cells was increased[(35.38±3.31)%], without significant difference (P>0.05). The G0/G1 phase of T24/CDDP cells[(60.42±3.25)%]was significantly more than that of T24 cells[(47.25±4.17)%], and the G2/M phase of T24/CDDP cells[(8.95±2.81)%]was significantly less than that of T24 cells[(17.37±3.46)%](t=4.31, P=0.006; t=3.27, P=0.015). Western blot showed that expressions of PKCα and P-gp in T24/CDDP cells were significantly higher than T24 cells[(3.12±0.11) vs (1.37±0.06), t=24.19, P=0.00; (1.98±0.08) vs (0.47±0.03), t=30.61, P=0.00]. Conclusions T24/CDDP cell line showed a typical resistant phenotype and biological characteristics, which may be related to the overexpression of PKCα and P-gp protein. Key words: Urinary bladder neoplasms/DT; Cisplatin/TU; Drug resistance, neoplasm