Down-regulation of vascular endothelial growth factor in human colon carcinoma cell lines by antisense transfection decreases endothelial cell proliferation.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent paracrine angiogenic factor implicated in human colon cancer angiogenesis. This study determined whether regulation of VEGF expression by human colon cancer cell lines affects endothelial cell proliferation in an in vitro model of angiogenesis.
METHODS: Human colon carcinoma cell lines were screened for VEGF mRNA expression. SW480 cells (low VEGF expresser) were transfected with the VEGF sense (VS) vector, and SW620 cells (high VEGF expresser) were transfected with the VEGF antisense (VAS) vector. Cells were transfected with the vector alone as control. Endothelial cells were grown in conditioned, serum-free medium produced from experimental cells, and proliferation was determined.
RESULTS: SW480-VS transfectants exhibited a sixfold increase in VEGF secretion. SW620-VAS transfectants exhibited a 50% reduction in VEGF secretion. Endothelial cells grown in conditioned medium from SW480-VS cells exhibited a 1.5- to 2-fold increase in proliferation. Addition of conditioned medium from SW620-VAS cells resulted in a 25% to 50% decrease in endothelial cell proliferation.
CONCLUSIONS: VEGF production by human colon cancer cells regulates endothelial cell proliferation. Antisense VEGF transfection can down-regulate VEGF secretion and biologic activity. Therapies to decrease VEGF expression may be a means of inhibiting angiogenesis in primary and metastatic colon cancer.