Tyrosine kinase receptor inhibitor-targeted combined chemotherapy for metastatic bladder cancer

• Published in: The Kaohsiung journal of medical sciences 2012-04, Vol.28 (4), p.194-203
• Main Authors: Wu, Chia-Lun, Ping, Szu-Yuan, Yu, Cheng-Ping, Yu, Dah-Shyong
• Format: Article
• Language: English
• Subjects: Angiogenesis inhibitors; Animals; Antineoplastic Agents - pharmacology; Antineoplastic Agents - therapeutic use; Apoptosis - drug effects; Cancer; Cell Cycle - drug effects; Cell Line, Tumor; Chemotherapy; Epirubicin - pharmacology; Epirubicin - therapeutic use; Ethylenediaminetetraacetic acid; Female; Humans; Indoles - pharmacology; Indoles - therapeutic use; Internal Medicine; Metastasis; Metastatic bladder cancer; Mice; Neoplasm Metastasis; Phenols; Pyrroles - pharmacology; Pyrroles - therapeutic use; Receptor Protein-Tyrosine Kinases - antagonists & inhibitors; RNA; Target therapy; TKRi; Transitional cell carcinoma; Tyrosine; Urinary Bladder Neoplasms - drug therapy; Urinary Bladder Neoplasms - metabolism; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - genetics
• ISSN: 1607-551X; 2410-8650
• DOI: 10.1016/j.kjms.2011.06.020

Abstract Overexpression of hypoxia-inducible factor-1 alpha is noted during the invasive and metastatic process of transitional cell carcinoma. It will upregulate vascular endothelial growth factor (VEGF) and drive proliferation, invasiveness, metastasis, and antiapoptotic ability of cancer cells. We proposed that tyrosine kinase receptor inhibitor, sunitinib malate—(Sutent; Pfizer Inc., Taiwan), combined with chemotherapeutic drug may present synergistic cytotoxic enhancement to transitional cell carcinoma cells with subsequent inhibition of their cellular behaviors, including proliferation, invasiveness, and metastatic activity. The contents of VEGF-A in mouse bladder tumor cells (MBT-2) and culture medium were detected by quantification-polymerase chain reaction and Western blot individually. The inhibitory concentrations of various chemotherapeutic drugs, sunitinib, and their combination treatment in MBT-2 were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Microchamber transmembrane migration assay was applied in evaluation of the inhibitory effects of different dosages of sunitinib and combination treatment on tumor cells. The cell cycle and apoptosis were analyzed after combination therapy by flow cytometry. Variation in apoptotic pathway was elucidated by Western blot using specific antibodies with cleaved PARP and caspase-3. Metastatic animal model mimicked by tail vein injection of MBT-2 cells was used to evaluate the treatment efficiency in tumor weight and survival rate. The mRNA and protein level of VEGF-A in MBT-2 cells increased by 70% at 48 hours interval under hypoxia stress condition. In MTT assay, MBT-2 cells had shown the highest sensitivity to epirubicin. Sunitinib combined with epirubicin had shown a synergistic cytotoxic effect to MBT-2 cells. Sunitinib and its combination with epirubicin showed significant inhibition on MBT-2 cells migration in microchambers. G2/M phase arrest and increased subG1 in cell cycle was seen in the epirubicin and sunitinib combination treatment group. The activation of apoptosis pathway was confirmed by increased cleaved caspase-3 and cleaved PARP in MBT-2 cells. In tail vein tumor inoculation C3H mice model, epirubicin alone and sunitinib combination therapy decreased tumor growth in lungs with marginal effect. Sunitinib and epirubicin combination had shown a synergistic cytotoxic effect and inhibited cell migration ability in MBT-2 cells. The combination can