Interferon-α-mediated down-regulation of angiogenesis-related genes and therapy of bladder cancer are dependent on optimization of biological dose and schedule

The purpose of this study was to identify and optimize the antiangiogenic activity of IFN-alpha against human bladder cancer cells growing in the bladder of nude mice, 253J B-V IFNR cells (resistant to antiproliferative effects of IFN-alpha or IFN-beta) were implanted into the bladder wall of nude mice, Three days later, the mice were treated with s.c. injections of IFN-alpha (70,000 units/week) at different dosing schedules (1, 2, 3, or 7 times/week), Daily therapy with IFN-alpha produced the most significant inhibition of tumor growth, tumor vascularization, and down-regulation of basic fibroblast growth factor and matrix metalloprotease-9 mRNA and protein expression. Changing dose and schedule of IFN-alpha administration had minimal effects on the expression of vascular endothelial growth factor or interleukin 8. The daily s.c. administrations of 5,000 or 10,000 units IFN-alpha-2a produced maximal inhibition of bFGF and MMP-9 expression (mRNA and protein), maximal reduction in tumor vessel density, and maximal reduction in serum levels of bFGF, Daily administration of higher doses of IFN-alpha failed to produce significant antiangiogenic effects. These data suggest that the antiangiogenic activity of IFN-alpha is dependent on frequent administration of optimal biological dose and not maximal tolerated dose.