Glucocorticoids suppress tumor angiogenesis and in vivo growth of prostate cancer cells: Yano A, Fujii Y, Iwai A, Kageyama Y, Kihara K, Department of Urology, Tokyo Medical and Dental University, Yushima, Tokyo, Japan

Abstract

Purpose Glucocorticoids, such as prednisone, hydrocortisone, and dexamethasone, are known to produce some clinical benefit for patients with hormone-refractory prostate cancer (HRPC). However, the underlying mechanisms by which glucocorticoids affect HRPC growth are not well established as yet. Here, we hypothesize that the therapeutic effect of glucocorticoids on HRPC can be attributed to a direct inhibition of angiogenesis through the glucocorticoid receptor by down-regulating two major angiogenic factors, vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8). Experimental Design The effects of dexamethasone on VEGF and IL-8 expression and cell proliferation were examined using DU145, which expresses glucocorticoid receptor. The effects of dexamethasone on DU145 xenografts were determined by analyzing VEGF and IL-8 gene expression, microvessel density, and tumor volume. Results Dexamethasone significantly down-regulated VEGF and IL-8 gene expression by 50% (P Conclusion Glucocorticoids suppressed androgen-independent prostate cancer growth possibly due to the inhibition of tumor-associated angiogenesis by decreasing VEGF and IL-8 production directly through glucocorticoid receptor in vivo.