Endostatin Effects on Tumor Cells and Vascular Network of Human Renal Cell Carcinoma Implanted on Chick Embryo Chorioallantoic Membrane.

Rare and inconsistent data are reported for chorioallantoic tumor models of renal cell carcinoma and none of them has used endostatin as an inhibitory agent of tumor development. We aimed to perform a comparative analysis of tumor cells and blood vessels from renal cell carcinoma on endostatin-treated and non-treated chorioallantoic membrane (CAM) implants by the assessment of endoglin, vascular endothelial growth factor (VEGF) and smooth muscle actin expression. Endostatin triple action on tumor, endothelial and perivascular cells was observed in the present study. Differential impact of endostatin treatment on intratumor and peritumor blood vessels was noticed on the VEGF expression and behaviour of tumor cells between clear cell and papillary components of RCC. Based on our findings, a high tumor heterogenity response to endostatin has been highlighted. Interplay between VEGF, endoglin and endostatin in RCC could support a combined targeted therapy to improve prognosis of patients with RCC and reduce therapy resistance often developed by monotherapy.