Screening method and application of human colon cancer cell specific binding polypeptide

Abstract

The invention relates to a polypeptide specifically bound with the surfaces of colon cancer cells and application of the polypeptide. A method for screening the polypeptide includes steps of (1), incubating clone strains with amplified bacteriophage dodecapeptide libraries and the colon cancer cells together, discarding the clone strains which are not bound with the colon cancer cells, screening the clone strains and then amplifying the screened clone strains which are bound with the colon cancer cells; (2), repeatedly carrying out the step (1) by four times, continuously enriching bacteriophage clone strains to obtain clone strains with high colon cancer cell affinity and repeatedly verifying the binding capacity of the bacteriophage clone strains in liquid phases; (3), incubating the bacteriophage clone strain obtained at the step (2) and normal colonic epithelial cells and removing non-specifically bound clone strains; (4), carrying out sequencing on positive clone strains; (5), verifying the specificity of the polypeptide on the clone cancer cells and tissues by the aid of immunofluorescence. The polypeptide and the application have the advantages that short peptides which are specifically bound with the colon cancer cells are screened by the aid of technologies for displaying peptide libraries by the aid of bacteriophage, and the polypeptide can be used as a molecular marker or targeted carrier or the like for targeted therapeutic medicines.

Description

technical field [0001] The invention relates to the field of medicine, in particular to a screening method for specific binding polypeptides on the surface of colon cancer cells and its application. Background technique [0002] Colon cancer is one of the common malignant tumors of the digestive system. Its incidence rate is second only to gastric cancer and esophageal cancer. It seriously affects human life and health. At present, there are 440,000 newly diagnosed cases of colorectal cancer in my country every year, and as many as 230,000 patients die every year. . Early detection and early resection of precancerous lesions and focal cancer can effectively reduce the mortality rate of colorectal cancer. However, due to the slow development of colon cancer, the early symptoms are not obvious. 6% of asymptomatic people over the age of 40 suffer from early colon cancer, 70%-80% of colon cancer patients have entered the middle and late stages when they are diagnosed, and more t...

AI Technical Summary

Problems solved by technology

The curative effect of metastatic colon cancer surgery is poor, the recurrence rate is high after surgery, and the 5-year survival rate of patients with unresectable tumors is almost zero

Although drug-targeted therapy has achieved great success, there are still many deficiencies such as the large molecular weight of the antibody used for targeting, low penetration in tumor tissue, and toxic effects on the liver and bone marrow; strong immunogenicity; preparation The process and cycle are long, expensive, etc.

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