Expression data of multple drug resistant bladder cancer cell model constructed by repeated exposure to pirarubicin treatment

Bladder cancer has a high incidence worldwide accompanies by high recurrent rate after treatment. The emergence of primary or acquired chemotherapy resistance leads to poor efficacy in many cases. Therefore, there is an urgent need to elucidate the mechanism underlying drug resistance and enhance the sensitivity of cancer cells to chemotherapy. To explore the underlying mechanisms of drug resistance, we firstly established a drug-resistant cell model T24/THP by repeated exposure of T24 cells to pirarubicin (THP) whose concentration increases gradually. After a stable mode of drug resistance of cancer cell had been repeatedly tested, we performed a gene expression profiling by microarray. The human bladder cancer cell line T24 were bought from the Type Culture Collection of the Chinese Academy of Sciences (Shanghai, China) and cultured in RPMI-1640 supplemented with 10% fetal bovine serum (FBS) under environment where the temperature is 37°C and CO2 concentration in the air is 5%. In order to establish the multiple drug resistance (MDR) bladder cancer cell line, T24 was initially cultured in the medium containing 5ng/ml pirarubicin for 24 hours and then replaced with normal culture medium without drug. Once the cells returned to an optimal state, the exposure to pirarubicin as described above was repeated with a gradually increasing concentration gradient containing 5, 10, 20, 50, 100, 200, 500 to 1000 ng/ml. In order to maintain the resistance, we added drugs at regular interval (every 2-3 weeks depends on cell state and counts). Parent cell line T24 were also cultured during the process of resistance cell establishment so that we can measure and compare IC50 continuously to ensure the development of resistance. The whole process lasted for over 6 months and finally we obtained the MDR bladder cell line T24/THP after a series of drug resistance tests were carried out. Afterwards, total RNA of both T24 and T24/THP (3 independent samples for each cell line) was firstly extracted, purified, amplified, and labeled in order to obtain biotin labeled cDNA for microarray test and analysis in order to obtain the different expressed genes between drug sensitive and resistant cell lines.