Expression of Bcl-2 and Bax in cis-Diamminedichloroplatinum (II)-Resistant Bladder Cancer Cell Lines.
- Author:
Cheryn SONG
1
;
Tae jin KANG
;
Dal san YOU
;
Jun Hyuk HONG
;
Han jong AHN
Author Information
1. Department of Urology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Bladder neoplasms;
Cisplatin;
Bcl-2 genes;
Antisense oligonucleotides
- MeSH:
bcl-2-Associated X Protein;
Blotting, Western;
Cell Line*;
Cisplatin*;
Clinical Coding;
Down-Regulation;
Drug Resistance;
Drug Therapy;
Drug Therapy, Combination;
Genes, bcl-2;
Inhibitory Concentration 50;
Oligonucleotides, Antisense;
Transfection;
Up-Regulation;
Urinary Bladder Neoplasms*;
Urinary Bladder*
- From:Korean Journal of Urology
2004;45(5):472-477
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: Development of drug resistance has been the major obstacle in cis-Diamminedichloroplatinum (II) (cisplatin)-based combination chemotherapy in the treatment of advanced bladder cancer for which a variety of mechanisms has been suggested. We investigated to determine the changes of expression of apoptotic regulator proteins Bcl-2 and Bax in cisplatin-resistant bladder cancer cell lines and the reversibility of chemoresistance with antisense oligonucleotide against Bcl-2. MATERIALS AND METHODS: In T24, J82, 253J, 253J-BV and HT-1376 bladder cancer cell lines, we established cisplatin-resistance using stepwise exposure to cisplatin. The changes of Bcl-2 and Bax proteins in the resistant cell lines were determined by Western blot. Then, after administration of antisense oligonucleotide targeting the Bcl-2 coding sequence to the T24, T24-R1, and T24-R2 cell lines with lipofectamine, changes of Bcl-2 expression were determined along with cisplatin cytotoxicity before and after transfection. RESULTS: We confirmed the acquisition of cisplatin resistance in all 5 cell lines as the percent increase of IC50 in each cell lines were 210%, 175%, 181%, 280% and 153%, respectively. The expression of Bcl-2 protein increased in all 5 cisplatin-resistant cell lines, while the expressions of Bax decreased in 4 of 5 cisplatin-resistant cell lines. Treatment with antisense oligonucleotide significantly enhanced the cytotoxicity of cisplatin in T24, T24-R1 and T24-R2 cell lines. CONCLUSIONS: These results suggest that the up-regulation of Bcl-2 expression as well as down-regulation of Bax expression may be one of the mechanisms of cisplatin resistance in bladder cancer cells, and antisense Bcl-2 oligonucleotide may be helpful in chemotherapy of bladder cancer by reversing cisplatin resistance.
