Vascular density and endothelial cell expression of integrin alpha v beta 3 and E-selectin in murine tumours

The endothelial cell adhesion molecules, including the integrin alpha v beta 3 (αvβ3) and E-selectin, are involved in the process of angiogenesis required for tumour growth, cell migration and metastasis. The purpose of this study was to assess and compare widely used tumour models to select the ones most suitable for angiogenesis research. Fifteen murine tumours were selected including melanoma (B16), colon (C26, C38, C51), mammary (MA13, MA16, MA16/Adr, MA17, MA17/Adr, MA25, MA44), pancreatic (PO2, PO3), Glasgow osteogenic sarcoma (GOS) and Lewis lung carcinoma (LLC). The tumour vascular density, assessed using the platelet endothelial cell adhesion molecule 1 (PECAM-1; CD31) immunostaining, revealed that B16 melanoma was poorly vascularized (<5 %), whereas the colon and mammary tumours were well vascularized (5-15 %). The most vascularized tumours (>15 %) were the pancreatic tumours (PO2 and PO3), the sarcoma (GOS) and the lung tumour (LLC). The integrin αvβ3 and E-selectin, evaluated by immunohistology, showed that 7/15 tumours expressed the αvβ3 integrin which was homogeneously distributed on all tumour sections (B16, C26, MA17/Adr, MA25, MA44, PO2, LLC). E-selectin was expressed in 4/15 tumours and its expression was restricted to the tumour periphery. Only 2/15 tumours (B16 and C26) were shown to express both integrin αvβ3 and E-selectin. In conclusion, these data not only contribute to a better understanding of the tumour biology of murine tumours but can also guide the choice of appropriate models for antiangiogenic therapy, for selective drug delivery to tumours and the validation of tumour imaging modalities targeting these endothelial cell adhesion molecules.