Review Article

Targeted Delivery of siRNA Therapeutics to Malignant Tumors

Figure 3

Proposed mechanism of CendR tumor-peptides to transport NPs into tumor matrix. After a CendR peptide such as iRGD binds to av integrins, furin-like enzymes cleave the cyclic peptide (dash line) on the carboxyl side of the lysine group. With reduction of the cystine linkage (solid line), the peptide, KDGR, binds to the neuropilin receptor and activates the transcytosis pathway. The peptide together with the NP is then endocytosed and transported through the endothelial cell to the tumor milieu. E, endosome.