Investigation Of Targeting Chemotherapy Of Colon Cancer Based On Specific Peptides

Objective:1.Observing the specific binding capacity of peptides to human colon cancer cells and tissue;2.Linking pepide to chemotherapeutic agents campothecin by click chemistry;3.Studying the cytotoxicity of peptide-chemotherapeutic agents on colon cancer cells in vitro.4.Exploring the role of peptides in colon cancer targeted chemotherapy in vivo.Methods:1.Using immunofluorescence and other experiments to check the binding capacity of FITC-labeled peptides to colon cancer cells.2.The specific binding capacity of peptide to human colon cancer tissues was studied by exploiting frozen section immunofluorescence.3.Predicting the binding receptor proteins of peptides and colon cancer cells based on bioinformatics blast results,and subsequently re-test at the cellular level.4.Measuring the influence of peptide on breast cancer cell proliferation through colorimetric CCK-8 assay.5.Linking pepide to chemotherapeutic agents campothecin by click chemistry method.6.Studying the effect of peptide-CPT on proliferation,apoptosis and clonality of colon cancer cells by CCK8,Edu,clone formation,flow cytometry and reactive oxygen species detection.7.The uptaking of peptide-CPT by colon cancer cells was observed under confocal laser scanning microscopy.8.The selectively binding and concentrating of ⁶⁸Ga-labelled peptide to colon cancer cells were observed in subcutaneous colon cancer nude mice by Micro PET scan;9.Evaluation of the anti-tumor effect and toxic side effects size of CPT-peptide by constructing the subcutaneous tumorigenic model of colon cancer and PDX model respectively by measuring the tumor size,tumor weight,intestinal epithelial cell damages etc.Results:1.The results showed that FITC-P-DWS and P-LPK have a remarkable binding capacity with several colon cancer cell lines,while sparing to normal colonic epithelial cells.2.FITC-P-DWS and FITC-P-LPK selectively bind to human colon cancer tissues but not with adjacent normal tissue.3.Glypican-3 may be the receptor of P-DWS.4.The peptides have no effect on the proliferation of colon cancer cells.5.P-DWS and P-LPK were linked to CPT through click chemistry method and further study found that P-DWS-CPT can not enhance the killing effect of CPT on colon cancer cells,but P-LPK-CPT significantly enhanced the targeted cytotoxicity of CPT on colon cancer cells.6.The selective uptaking of P-LPK-CPT was observed in colon cancer cells.7.The gathering of ⁶⁸Ga-P-LPK in tumors of nude mice was remarkably seen.8.P-LPK-CPT could effectively inhibit the growth of colon cancer with a prolonging survival of nude mice,however,with less side effects on liver and intestinal epithelial cells.Conclusions:1.P-DWS and P-LPK can specifically bind to colon cancer cells and human colon cancer tissues.2.The selective antitumor effect of P-LPK-CPT was seen in vitro.3.The peptide P-LPK shows good tumor targeting ability in nude mice and P-LPK-CPT effectively inhibit the growth of colon cancer while the side effects of CPT are less.Our study provides a new strategy for the treatment of colon cancer.