Figure 1.

Delivering VEGF-specific siRNA into tumor cells resulted in the downregulation of VEGF gene expression. In the cytoplasm of the transfected tumor cell, the VEGF-specific siRNAs released from the delivery carrier are incorporated into a multi-protein RNA-inducing silencing complex (RISC). The siRNA duplex is unwound within the RISC in a process that requires ATP. Once unwound, the single-stranded antisense strand guides RISC to its homologous target: VEGF mRNA that has a complementary sequence. This results in the endonucleolytic cleavage of the target VEGF mRNA and a consequent knockdown of VEGF protein levels in the transfected tumor cells.