iRGD peptide is a 9-amino acid cyclic peptide, triggers tissue penetration of agents by first binding to av integrins , then proteolytically cleaved in the tumor to produce CRGDK/R to interact with neuropilin-1, and has tumor-targeting and tumor-penetrating properties. In Vitro iRGD peptide-mediated tumor penetration occurs in three steps: binding to αv-integrins on tumor vasculature or tumor cells, exposure by proteolysis of a C-terminal motif that binds to neuropilin-1 (NRP-1) and cell internalization. iRGD peptide inserted in the ICOVIR15K fiber C terminus enhances binding and internalization only in MCF7 cells, which express NRP-1 and integrins. iRGD insertion does not impair virus infection and replication. iRGD peptide alone has no obvious effect on gastric cancer cells, and when combined with 5-FU, iRGD peptide (0.3 μmol/mL) enhances the chemotherapy efficacy of 5-FU on gastric cancer cells through NRP1. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo iRGD inserted in the oncolytic adenovirus ICOVIR15K (ICOVIR15K-iRGD) enhances early adenovirus dissemination through the tumor mass and elevates the antitumor effect in mice . iRGD (4 mmol/kg, i.v.) in combination with 5-FU significantly suppresses the tumor growth in nude mice bearing human gastric cancer cells. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal administration Mice 12 male BALB/c nude mice (4-week-old) are assigned to 4 groups with 3 mice in each group. Among them,two groups are subcutaneously injected into the flanks by 3 × 10 6 HCG27 cells , the other two groups are conducted by NCI-N87 cells. Experimental groups are intravenously injected by 5-FU (25 mg/kg) mixed with iRGD peptide (4 mmol/kg) at every three days for 4 weeks while control groups are treated by 5-FU (25 mg/kg) mixed with PBS. And tumor volume is computed every 1 week with a digital vernier caliper using the following formula: tumor volume = (length × width 2 )/2 . aladdin has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:Integrin