Apoptotic pathways of epothilone BMS 310705.
OBJECTIVE
BMS 310705 is a novel water-soluble analog of epothilone B currently in phase I clinical evaluation in the treatment of malignancies such as ovarian, renal, bladder, and lung carcinoma. Using an early passage cell culture model derived from the ascites of a patient clinically refractory to platinum/paclitaxel therapy, we evaluated the pathway of caspase-mediated apoptosis.


METHODS
Cells were treated for 1 h and subsequently evaluated for apoptosis, survival, and caspase activity. Apoptosis was determined by fluorescent microscopy. Caspase-3, -8, and -9 activities were determined by fluorometry using target tetrapeptide substrates. Mitochondrial release of cytochrome c was determined by immunoblot analysis.


RESULTS
After treatment with BMS 310705, apoptosis was confirmed in >25% of cells at 24 h. Survival was significantly lower (P < 0.02) in cells treated with 0.05 micro M BMS 310705 vs paclitaxel. Analysis revealed an increase of caspase-9 and -3 activity; no caspase -8 activity was observed. Release of cytochrome c was detected at 12 h following treatment. SN-38 and topotecan failed to induce apoptosis.


CONCLUSIONS
BMS 310705 induces significant apoptosis, decreases survival, and utilizes the mitochondrial-mediated pathway for apoptosis in this model.
Uyar
Denise
D
The Cleveland Clinic Foundation, Experimental Therapeutics Program, Taussig Cancer Center/R40, 9500 Euclid Avenue, Cleveland, OH 44195, USA. uyard@ccf.org
Takigawa
Nagio
N
Mekhail
Tarek
T
Grabowski
Dale
D
Markman
Maurie
M
Lee
Francis
F
Canetta
Renzo
R
Peck
Ron
R
Bukowski
Ronald
R
Ganapathi
Ram
R
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation / Q000187:drug effects; D034261:Epothilones / Q000494:pharmacology*; D005260:Female; D006801:Humans; D000077146:Irinotecan; D007527:Isoenzymes / Q000378:metabolism; D009944:Organoplatinum Compounds / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology; D019772:Topotecan / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; C478223:BMS 310705; D003574:Cytochrome c Group; D034261:Epothilones; D007527:Isoenzymes; D009944:Organoplatinum Compounds; D000077146:Irinotecan; D019772:Topotecan; D020169:Caspases; D017239:Paclitaxel; D002166:Camptothecin