Ligand/target1 Carrier siRNA and/or active moiety Cells Results Other comments References cRGD2 / v 3/ 5 Polymer (PEI)3 siVEGFR2 N2A neuroblastoma allografts, implanted SC Marked inhibition of tumor growth (versus nontargeted NP) May target physiologic angiogenesis [22 ] Blocked copolymers micelles siVEGF /siVEGFR2 HeLa xenografts, SC Marked inhibition of tumor growth Silencing both VEGFR2 /VEGF more effective than either alone [27 ] APRPG/VEGFR-1 Polymer (PEI) siVEGF MCF7 xenografts, SC Targeted and nontargeted PEG-NP inhibited tumor similarly Reduction of intratumoral VEGF and mRNA greater with targeted NP [34 ] Liposome si-mTOR B16F10, IV, tumor-laden lungs Targeted and nontargeted NP reduced tumor burden similarly Wild-type PTEN expressing tumors [35 ] cNGR/CD13 Liposome sic-MYC /doxorubicin HT-1080 (fibrosarcoma) xenografts, SC Tumor uptake and inhibition greater with targeted NP HT-1080, a CD13+ cell [38 ] F3/nucleolin Silk-polylysine-copolymer NP Plasmid-based luciferase expression MDA-MB-231 xenografts, SC Targeted NP increased gene expression in tumors Only study in vivo with F3 ligand; F3 more effective than CGKRK in vitro [44 ] Liposomes siPLK1 PC3 (in vitro study) Uptake and silencing greater with targeted therapy Cells pretreated with siPLK1 were more sensitive to the inhibitory effects of paclitaxel [42 ] CGKRK/p32 Nanoworms Mitochondria-targeting peptide Orthotopic breast cancer model (MCF10CA1a) Targeted NP gave greater tumor inhibition than nontargeted NP Addition of iRGD increased tumor inhibition of targeted NP [45 ] iRGD PEI micelles Shsurvivin/paclitaxel A549 lung cancer xenografts, SC Greater tumor size inhibition with targeted therapy Plasmid-based expression of shRNA; dose-response inhibition; no siRNA studies yet [51 ]