title: Cinnarizine and flunarizine improve the tumour radiosensitisation induced by erythrocyte transfusion in anaemic mice.
abstract: The ability of the calcium antagonists, cinnarizine and flunarizine, to enhance the radiosensitisation produced by the administration of an erythrocyte transfusion to anaemic, RIF-1 or SCCVII/St tumour bearing mice was determined. Erythrocyte transfusion alone increased radiation cell killing 10-fold in the RIF-1 tumour when given 0-4 h before X-rays. In contrast, the SCCVII/St showed only a 4-fold increase in sensitivity, apparent when erythrocytes were given 2-6 h before irradiation. The administration of 50 mg kg-1 cinnarizine or flunarizine to anaemic mice followed by erythrocyte transfusion 0 h before X-rays produced the same level of cell survival for both tumours, a 20-fold increase in cell killing for cinnarizine, and a 30-40-fold effect for flunarizine, even though at this time interval, the erythrocyte transfusion alone did not sensitise the SCCVII/St tumour to X-rays. Further investigations indicated, however, that the erythrocyte transfusion was necessary to achieve the sensitisation with the calcium antagonists, since giving flunarizine to anaemic mice alone only achieved a 4-fold increase in radiation cell killing. In addition, flunarizine given with erythrocyte transfusion 4 h before X-rays, in SCCVII/St, the optimal time for radiosensitisation in this tumour, did not further increase the level of cell killing achieved by flunarizine plus erythrocyte transfusion 0 h before X-rays.
authors: Department of Radiation Oncology, Stanford University School of Medicine, CA 94305.
authors: P J
authors: PJ
authors: Wood
authors: D G
authors: DG
authors: Hirst
mesh_terms: D000740:Anemia / Q000150:complications*; D000818:Animals; D001803:Blood Transfusion; D002936:Cinnarizine / Q000627:therapeutic use*; D017707:Erythrocyte Transfusion; D005260:Female; D005444:Flunarizine / Q000627:therapeutic use*; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000150:complications / Q000532:radiotherapy*; D011838:Radiation-Sensitizing Agents
chemical_list: D011838:Radiation-Sensitizing Agents; D002936:Cinnarizine; D005444:Flunarizine