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.
Bolenz
Christian
C
Department of Urology, University Hospital Mannheim, Mannheim, Germany. christian.bolenz@uro.ma.uni-heidelberg.de
Becker
Andreas
A
Trojan
Lutz
L
Schaaf
Axel
A
Cao
Yanwei
Y
Weiss
Christel
C
Alken
Peter
P
Michel
Maurice Stephan
MS
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