title: Bleomycin induced changes in growth and cell kinetics of a heterotransplanted squamous cell carcinoma of the head and neck.
abstract: Bleomycin (BLM) is often used against squamous cell carcinomas in combination with other drugs in phase-specific schedules since it has been considered a synchronizing agent. However, the reported effects on the cell cycle are contradictory. In the present study a poorly differentiated squamous cell carcinoma of the head and neck, heterotransplanted to nude mice was used for evaluation of BLM induced suppression of growth, and, measured with flow cytometric technique, cell cycle traverse and cell cycle phase distribution. BLM was administered once daily for four days. The dose-response curve exhibited a plateau-phase beginning at a total dose of 200 mg BLM/kg. A single dose of 75 mg BLM/kg caused a transient accumulation of cells in G0 + G1 phase and was followed by a synchronized passage of cells through the cell cycle. However, the induced perturbations were small. Cell kinetic analysis of tumours treated with repeated doses of BLM did not result in increased cell cycle perturbations. Thus, the present study could not confirm any major cell synchronizing effect of BLM on poorly differentiated heterotransplanted human squamous cell carcinoma.
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation
chemical_list: D001761:Bleomycin