Purpose: We investigated the role of vascular endothelial growth factor C (VEGF-C) in esophageal squamous cell carcinoma (ESCC) by knocking down VEGF-C expression in the ESCC cell line EC9706.
Methods: Immunohistochemistry and in situ hybridization techniques were used to detect the expression of VEGF-C expression in ESCC tissues. We also investigated the relationship between VEGF-C expression and lymph node metastasis. We designed a siRNA expression plasmid for VEGF-C and transfected it into EC9706 cells. Stable clones were selected, and VEGF-C expression was analyzed by RT-PCR and western blotting. Cells were inoculated into nude mice. The expression of VEGF-C in the resulting tumors was analyzed by immunohistochemistry and in situ hybridization.
Results: VEGF-C is highly expressed in ESCC and correlated with lymph node metastasis, as high levels were observed in patients presenting with lymph node metastases relative to those who did not (P < 0.01). Transfection with VEGF-C-siRNA decreased the expression of VEGF-C mRNA and protein. ESCC cells stably transfected with VEGF-C-siRNA expressed very low levels of VEGF-C (P < 0.01 compared with control). This knockdown effect persisted when the cells were inoculated into nude mice and allowed to form tumors.
Conclusions: The siRNA-targeted knockdown of VEGF-C led to a significant reduction in VEGF-C expression. This siRNA technique could be used for gene therapy in ESCC.