Background: Integrin signal transduction pathways provide an important basis for molecular targeting therapy of cancerin tumor growth

infiltration and transfer.Existing research data have shown that small molecular peptide labeled with radionuclide has good clinical application prospects

but the successful researches on lung cancer have not been reported so far.It is considered that the main reason is the lack of small molecule peptide for specific targeting lung cancer.Purpose: Based on the small molecular peptide cNGQGEQc for specifically identifying integrin α3 and β1 found previously

polypeptide cNGQGEQc is selected and radiolabelled with 131I.And the inhibitory effect of131I-cNGQGEQc in nude mice bearing lung adenocarcinoma is observed.Methods: The coupling of cNGQGEQc and tyrosine was done in the processing of solid phase synthesis of small molecular peptide.Chloramine-T method was used for radiolabelling of cNGQGEQc with 131I.Twenty nude mice bearing NCI-H1975 were built and randomly divided into four groups with five mice in each group

including the group of 131I-cNGQGEQc

the group of131I-cNAQAEQc

the group of 131I and the saline control group.The general condition was observed in nude mice bearing tumor after tail vein injection of corresponding drugs.And the tumor sizes after grafting were measured per 3 days in 30 days.The inhibitory rate of tumor in each group was calculated.Results: The labeling efficiencies of 131I-cNGQGEQc and131I-cNAQAEQc were greater than 90% with the radiochemical purity of more than 95%

and 131I-cNGQGEQc had obvious inhibitory effect for transplantation tumor in nude mice bearing NCI-H1975 adenocarcinoma of lung.After a treatment for 30 days the tumor inhibitory rates were 60.93% for the group of131I-cNGQGEQc

11.63% for the group of131I-cNAQAEQ and 10.70% for the group of131I.Conclusion: 131I-cNGQGEQc has a good affinity and effective inhibit effect for the NCI-H1975 lung adenocarcinoma.Integrin is a promising targeting therapy agent for non-small cell lung cancer.