Constitutive upregulation of hypoxia-inducible factor-1α mRNA occurring in highly metastatic lung carcinoma cells leads to vascular endothelial growth factor overexpression upon hypoxic exposure

Neoangiogenesis is crucial for tumor growth and metastasis and is regulated by various angiogenic factors including vascular endothelial growth factor (VEGF). However, little is known whether highly metastatic cells express higher level of VEGF in response to various stimuli, thereby increasing neoangiogenesis compared to low-metastatic cells. Here we report that hypoxia markedly induced the expression of VEGF mRNA in the cell lines with...