Combretastatin A-4 inhibits cell growth and metastasis in bladder cancer cells and retards tumour growth in a murine orthotopic bladder tumour model.
OBJECTIVE
Bladder cancer is a highly recurrent cancer after intravesical therapy, so new drugs are needed to treat this cancer. Hence, we investigated the anti-cancer activity of combretastatin A-4 (CA-4), an anti-tubulin agent, in human bladder cancer cells and in a murine orthotopic bladder tumour model.


METHODS
Cytotoxicity of CA-4 was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, propidium iodide (PI) staining assay and clonogenic survival assay. In vivo microtubule assembly assay, cell cycle analyses, Western blot and cell migration assay were used to study the mechanism of CA-4. The effect of intravesical CA-4 therapy on the development of tumours was studied in the murine orthotopic bladder tumour model.


RESULTS
CA-4 inhibited microtubule polymerization in vivo. Cytotoxic IC(50) values of CA-4 in human bladder cancer cells were below 4 nM. Analyses of cell-cycle distribution showed CA-4 obviously induced G(2)-M phase arrest with sub-G(1) formation. The analyses of apoptosis showed that CA-4 induced caspase-3 activation and decreased BubR1 and Bub3 in cancer cells. In addition to apoptosis, CA-4 was also found to induce the formation of multinucleated cells. CA-4 had a significantly reduced cell migration in vitro. Importantly, the in vivo study revealed that intravesical CA-4 therapy retarded the development of murine bladder tumours.


CONCLUSIONS
These data demonstrate that CA-4 kills bladder cancer cells by inducing apoptosis and mitotic catastrophe. It inhibited cell migration in vitro and tumour growth in vivo. Hence, CA-4 intravesical therapy could provide another strategy for treating superficial bladder cancers.
Shen
Cheng-Huang
CH
Department of Urology, Chiayi Christian Hospital, Chiayi, Taiwan.
Shee
Jia-Jen
JJ
Wu
Jin-Yi
JY
Lin
Yi-Wen
YW
Wu
Jiann-Der
JD
Liu
Yi-Wen
YW
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D008810:Mice, Inbred C57BL; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology*; D013997:Time Factors; D050257:Tubulin Modulators / Q000494:pharmacology*; D047368:Tumor Burden / Q000187:drug effects; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology
D000972:Antineoplastic Agents, Phytogenic; D013267:Stilbenes; D050257:Tubulin Modulators; D051057:Proto-Oncogene Proteins c-akt; C058728:fosbretabulin