title: Sunitinib can enhance BCG mediated cytotoxicity to transitional cell carcinoma through apoptosis pathway.
abstract: Bacillus Calmette-Guerin (BCG)-refractory generated a high risk to patients with bladder cancer during treatment. Tyrosine kinase receptor (TKR) and TKR-mediated signal transduction pathways play an important role in tumor initiation, maintenance, angiogenesis, and vascular proliferation. Theoretically, it is helpful in adjuvant treatment for transitional cell carcinoma (TCC). Hence, we proposed that sunitinib, a endothelial growth factor receptor (VEGFR) inhibitor, may have a synergistic effect with BCG in enhancing its cytotoxicity to bladder cancer. The level of VEGF in various TCC cell lines was quantified by real time PCR. High grade TCC-T24 cell line with high level of VEGF expression was selected as representative tumor cells for further study. The single drug and combined inhibitory effects of BCG and sunitinib in T24 cells were determined by MTT method. The drug mediated cell apoptosis in T24 cells was characterized by flow cytometry with PI and annexin V stain. Bcl-2 apoptotic pathway induction by BCG and sunitinib treatment was evaluated by Western blotting method. Inhibitory ability of sunitinib in BCG induced cell migration was verified by cell migration assay. The results shown that expression level of VEGF mRNA in high grade T24 cells was higher than low grade J82, TSGH 8301, and TCC 9202 cell lines. Both BCG and sunitinib treatment presented cytotoxic effect to T24 cells in a dose-dependent manner. Combination of BCG and sunitinib revealed superior cytotoxicity effect than single agent when cells were pretreated with low dosage BCG before sunitinib treatment. By Annexin V analysis it was observed that cell death associated with increased early and late apoptosis process individually. Furthermore, the bcl-2 expression was significant reduced in T24 cells in metachronous BCG and sunitinib combination treatment than single agent. Tumor cell migration activity was also markedly inhibited with BCG and sunitinib combination treatment. In conclusion, these results suggested that during BCG and sunitinib combination treatment both reagents interacted with each other and caused TCC cells apoptosis in addition to direct cytotoxicity. This combination therapeutic model may have the potential for future clinical application to bladder cancer treatment.
authors.affiliation: Graduate Institute of Life Science and Pathology, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Szu-Yuan
authors.initials: SY
authors.lastname: Ping
authors.forename: Chia-Lun
authors.initials: CL
authors.lastname: Wu
authors.forename: Dah-Shyong
authors.initials: DS
authors.lastname: Yu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001500:BCG Vaccine / Q000494:pharmacology*; D000072224:Bcl-2-Like Protein 11; D015153:Blotting, Western; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D008565:Membrane Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D000077210:Sunitinib; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D001500:BCG Vaccine; C494811:BCL2L1 protein, human; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; D007211:Indoles; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011758:Pyrroles; D042461:Vascular Endothelial Growth Factor A; D051020:bcl-X Protein; D000077210:Sunitinib