Optimizing chemotherapy for transitional cell carcinoma by application of bcl-2 and bcl-xL antisense oligodeoxynucleotides.
OBJECTIVE
Therapy failure after intravesical and systemic chemotherapy for transitional cell carcinoma (TCC) is still high. Antiapoptotic proteins such as Bcl-2 and Bcl-xL have been reported to promote chemoresistance in TCC. Targeting bcl-2 and bcl-xL messenger ribonucleic acid with antisense oligodeoxynucleotides (AS-ODNs) may enhance the cytotoxic effects of chemotherapeutic agents. Therefore, we investigated the effects of bcl-2 and bcl-xL AS-ODNs in combined treatment with conventional and new chemotherapeutic agents to evaluate the cytotoxic effects in comparison to monotreatment.


METHODS
Western blot analysis or immunohistochemistry verified Bcl-2 and Bcl-xL expression in a panel of human TCC cell lines that had been monotreated with cisplatin, gemcitabine, mitomycin C, and paclitaxel. In addition, bcl-2 or bcl-xL AS-ODNs were applied in combination with each chemotherapeutic agent. Cell viability was determined using a standard MTT assay and Neubauer hemocytometry.


RESULTS
All cell lines responded to chemotherapeutic monotreatment in a dose-dependent manner. Maximum cell death rates after monotreatment were 47.4% (cisplatin), 39.0% (gemcitabine), 83.4% (mitomycin C), and 54.8% (paclitaxel). After combined treatment with chemotherapy and bcl-2 or bcl-xL AS-ODNs, cell death rates were significantly higher (e.g., 30.3% vs. 87.2% in HT 1197 cells for monotreatment vs. the combination of paclitaxel and bcl-xL AS-ODNs). Three-way analysis of variance revealed that combined treatment had a significant effect on all cell lines.


CONCLUSIONS
Our study confirms that the addition of bcl-2 and bcl-xL AS-ODNs enhances the cytotoxic potential of chemotherapeutic agents in TCC cell lines as a result of combined effects. Further trials in ex vivo and in vivo models have to be performed to promote clinical application in patients.
Department of Urology, University Hospital Mannheim, Mannheim, Germany. christian.bolenz@uro.ma.uni-heidelberg.de
Christian
C
Bolenz
Andreas
A
Becker
Lutz
L
Trojan
Axel
A
Schaaf
Yanwei
Y
Cao
Christel
C
Weiss
Peter
P
Alken
Maurice Stephan
MS
Michel
D000970:Antineoplastic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007150:Immunohistochemistry; D016685:Mitomycin / Q000494:pharmacology; D020320:Oligoribonucleotides, Antisense; D017239:Paclitaxel / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy*; D051020:bcl-X Protein / Q000037:antagonists & inhibitors*; D000093542:Gemcitabine
D000970:Antineoplastic Agents; D020320:Oligoribonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; D003841:Deoxycytidine; D016685:Mitomycin; D017239:Paclitaxel; D002945:Cisplatin; D000093542:Gemcitabine