Flavopiridol enhances the effect of docetaxel in vitro and in vivo in human gastric cancer cells.
Gastric cancer is one of the leading causes of cancer death throughout the world. It is a disease in desperate need of new therapeutic approaches. Docetaxel, a semisynthetic taxane, has shown potent activity against a broad range of solid tumors. However, in gastric cancer, response rates to docetaxel remain only approximately 20%. In these studies we show that flavopiridol, a cyclin-dependent kinase inhibitor, potentiates docetaxel-induced apoptosis 3-fold in MKN-74 human gastric cells. This effect is sequence dependent, such that flavopiridol must follow docetaxel to induce this effect. Docetaxel induces transient arrest in the M phase of the cell cycle. Cells exit mitosis in a specific time window without cytokinesis with a decrease in cyclin B1/cdc-2 kinase activity and MPM-2 labeling. Flavopiridol treatment of docetaxel-treated cells enhances the exit from mitosis with a more rapid decrease in mitotic markers including MPM-2 labeling and cyclin B1/cdc2 kinase activity. In contrast, pretreatment with flavopiridol prevents cells from entering mitosis by inhibiting cyclin B1/cdc-2 kinase activity, thus antagonizing the docetaxel effect. The testing of this combination against MKN-74 xenografts confirms the sequence dependency. Treatment of MKN-74 tumor-bearing xenografts with docetaxel at a dose of 10 mg/kg followed 3-7 h later by flavopiridol at a dose of 2.5 mg/kg resulted in a 1-18% decrease in tumor volume. In contrast, treatment with docetaxel alone at this same dose resulted in a 394% increase in tumor volume. When flavopiridol was given immediately after docetaxel, the effect was not statistically different from that of docetaxel alone. The reverse combination of flavopiridol followed 7 h later by docetaxel was similar to treatment with docetaxel alone. Flavopiridol alone had no effect in this tumor model. Thus, flavopiridol, when combined with docetaxel in a sequence-specific manner, may provide a completely new therapeutic approach in the treatment of gastric cancer.
Motwani
Monica
M
Gastrointestinal Oncology Research Laboratory, Division of Solid Tumor Oncology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Rizzo
Carina
C
Sirotnak
Francis
F
She
Yuhong
Y
Schwartz
Gary K
GK
D000970:Antineoplastic Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors; D002453:Cell Cycle; D045744:Cell Line, Tumor; D019926:Cyclin B / Q000037:antagonists & inhibitors / Q000378:metabolism; D056744:Cyclin B1; D000077143:Docetaxel; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D066298:In Vitro Techniques; D008938:Mitosis; D009368:Neoplasm Transplantation; D010880:Piperidines / Q000494:pharmacology*; D011419:Propidium / Q000494:pharmacology; D016160:Retinoblastoma Protein / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000628:therapy; D043823:Taxoids / Q000494:pharmacology*; D013997:Time Factors
D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010880:Piperidines; D016160:Retinoblastoma Protein; D043823:Taxoids; D000077143:Docetaxel; D011419:Propidium; C077990:alvocidib; D016203:CDC2 Protein Kinase