Vascular endothelial growth factor (VEGF)/ pigment epithelium derived factor (PEDF) balance in uveal melanoma

Abstract

Abstract: : Purpose: To determine the vascular endothelial growth factor (VEGF)/ pigment epithelium growth factor (PEDF) ratio in melanoma cell lines in the presence of anti–angiogenic agents. Methods: Frozen human uveal melanoma cell lines (Mel 290, Mel 285, Mel 270, OMM) and murine melanoma cell lines (B16LS9, B16F10, Queens) were thawed and grown to confluence in 6–well plates. The cells were exposed to varying concentrations of angiostatin and kringle 1–5 (K1–5). Controls were exposed to RPMI1650. Total RNA was extracted and the protein was purified for each cell line for VEGF and PEDF (caspin for murine cell lines). Quantitative real–time reverse transcription PCR (RT–PCR) was used to detect levels of VEGF and PEDF mRNA. Western blot was used to determine VEGF and PEDF protein expression. Results: All cell lines expressed VEGF and PEDF. The VEGF and PEDF ratios varied with increasing concentrations of angiostatin and K1–5. In general, VEGF/PEDF was 1 at angiostatin concentrations of 50 µg/ml. Conclusions: The VEGF/PEDF ratio for melanoma cell lines varies with concentration of angiostatin or K1–5. This may correlate with decreased micrometastasis in vivo with low–dose angiostatin therapy.

Keywords: melanoma • cytokines/chemokines • oncology