ENHANCEMENT OF PROSTATE-CANCER XENOGRAFT GROWTH WITH WHOLE-BODY RADIATION AND VASCULAR ENDOTHELIAL GROWTH-FACTOR

Prostate cancer research has been limited by the slow growth of human prostate tumors In athymic rodent models. This study sought to determi ne if low-dose radiation and vascular endothelial growth factor (VEGF) could enhance the development of PC-3 human prostate adenocarcinoma x enotransplanted into nude mice. Whole body radiation (2 Gy) was delive red only once, whereas VEGF (39 ng total/mouse) was injected subcutane ously over a 17-day period. The combination of the two agents, compare d to nontreated controls, resulted in significantly higher tumor incid ence (100% versus 50%) and more-rapid tumor progression (1288 mm(3) ve rsus 190 mm(3) by day 60). Treatment-associated changes were observed in body weights and assays of blood and spleen cells. In addition, H-3 -thymidine uptake by PC-3 cells cultured in the presence of VEGF and t ransforming growth factor-beta 1 was compared These results show that low-dose, whole-body radiation and VEGF can be used in concert safely and effectively to facilitate growth of PC-3 prostate tumor and that t he mechanisms of interaction may involve leukocyte modulation.