Human oral squamous cell carcinoma cell lines promote angiogenesis via expression of vascular endothelial growth factor and upregulation of KDR/flk-1expression in endothelial cells

Angiogenesis is an important phenomenon for the growth and metastasis of so lid tumors. The present study examined the characterization of angiogenic f actors produced by human oral squamous cell carcinoma (oral SCC) cell lines established from lymph node metastatic tumors and primary tumor in differe nt patients. The conditioned medium of HSC3 with the strongest metastatic a bility among the examined lines enhanced a tube-forming activity of bovine carotid artery endothelial (BAE) cells in collagen gel cultures. The treatm ent of HSC3 with anti-vascular endothelial growth factor (VEGF) antibody or anti-basic fibroblast growth factor (bFCF) antibody, either alone or in co mbination, attenuated the activity of urokinase-type plasminogen activator (uPA) in the endothelial cells stimulated by the conditioned medium of HSC3 . In contrast, neither anti-interleukin-8 (IL-8) antibody nor anti-hepatocy te growth factor (HGF beta) antibody affected uPA activity in the endotheli al cells. Among these HSC cell lines, HSC3 secreted VEGF with the highest ( 1.92 +/- 0.24 ng/10(6) cells/24 h) level and bFGF. The level of bFGF secret ed by HSC3 was lower than that secreted by BAE cells. Other oral SCC cell l ines secreted lower levels of VEGF and undetectable levels of bFGF. By reve rse transcriptase-polymerase chain reaction analysis of mRNA the production of VEGF(121), VEGF(145), VEGF(165), VEGF(189), and VEGF(206) in these cell lines was able to be detected. Moreover, the conditioned medium of HSC3 en hanced the tyrosine phosphorylation and expression of kinase insert domain- containing receptor (KDR/flk-1) in the endothelial cells. These results sug gest that oral SCC promotes angiogenesis via expression of VEGF and upregul ation of their receptor KDR/flk-1 expression in endothelial cells. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.