Objective:For small molecule drug 630120 based on proteolysis-targeting chimeras(PROTAC)that targets nicotinamide phosphoribosyltransferase(NAMPT),to explore its effect on the proliferation ability of colorectal cancer cells with low expression of nicotinate phosphoribosyltransferase(NAPRT).Methods:This study detected the protein expression levels of NAMPT and Tubby in tumor tissues and adjacent normal tissues from 5 colorectal cancer patients by immunohistochemical staining.Additionally,the Gene Expression Profiling Interactive Analysis(GEPIA)platform was used to analyze the expression level of NAMPT mRNA in colorectal cancer tissues and corresponding adjacent normal tissues from The Cancer Genome Atlas(TCGA)database.Based on previous studies in hematologic malignancies,to detect the degradation of NAMPT protein in colorectal cancer(CRC)cell lines(SW480,HT29,RKO,SW620 and HCT116)treated with the drug PROTAC-630120.Furthermore,to create NAPRT knockdown and knockout colorectal cancer cell lines by using shNAPRT plasmids and CRISPR-Cas9 technology.The impact of different concentrations of PROTAC-630120 on the proliferation of NAPRT knockdown and knockout colorectal cancer cells was validated by Cell Titer-Glo(CTG)luminescence assay and colony formation assay.Finally,Western blotting was also used to detect the effect of PROTAC-630120 on the expression of downstream proteins in the MAPK signaling pathway in colorectal cancer cells.Results:In colorectal cancer tissues,the expression levels of NAMPT protein and mRNA were significantly upregulated.The drug PROTAC-630120 can effectively degrade NAMPT protein in different colorectal cancer cells.Moreover,it can significantly inhibit the proliferation of NAPRT knockdown and knockout colorectal cancer cells.The IC50 values(half-maximal inhibitory concentration)for different colorectal cancer cell lines treated with PROTAC-630120 were as follows:RKOshNAPRT～49.03 nmol/L,HCT116shNAPRT～42.28 nmol/L,SW620shNAPRT～55.59 nmol/L,HT29shNAPRT～29.66 nmol/L,SW480shNAPRT～76.17 nmol/L,and SW480sgNAPRT～27.01/34.23 nmol/L.Finally,the drug PROTAC-630120 can inhibit the MAPK-ERK signaling pathway in colorectal cancer cells.Conclusion:The small molecule drug 630120 based on PROTAC that targets NAMPT protein,can inhibit the proliferation of NAPRT knockdown and knockout colorectal cancer cells,so it is expected to become a drug option for adjuvant therapy of cancer patients.

Objective:For small molecule drug 630120 based on proteolysis-targeting chimeras(PROTAC)that targets nicotinamide phosphoribosyltransferase(NAMPT),to explore its effect on the proliferation ability of colorectal cancer cells with low expression of nicotinate phosphoribosyltransferase(NAPRT).Methods:This study detected the protein expression levels of NAMPT and Tubby in tumor tissues and adjacent normal tissues from 5 colorectal cancer patients by immunohistochemical staining.Additionally,the Gene Expression Profiling Interactive Analysis(GEPIA)platform was used to analyze the expression level of NAMPT mRNA in colorectal cancer tissues and corresponding adjacent normal tissues from The Cancer Genome Atlas(TCGA)database.Based on previous studies in hematologic malignancies,to detect the degradation of NAMPT protein in colorectal cancer(CRC)cell lines(SW480,HT29,RKO,SW620 and HCT116)treated with the drug PROTAC-630120.Furthermore,to create NAPRT knockdown and knockout colorectal cancer cell lines by using shNAPRT plasmids and CRISPR-Cas9 technology.The impact of different concentrations of PROTAC-630120 on the proliferation of NAPRT knockdown and knockout colorectal cancer cells was validated by Cell Titer-Glo(CTG)luminescence assay and colony formation assay.Finally,Western blotting was also used to detect the effect of PROTAC-630120 on the expression of downstream proteins in the MAPK signaling pathway in colorectal cancer cells.Results:In colorectal cancer tissues,the expression levels of NAMPT protein and mRNA were significantly upregulated.The drug PROTAC-630120 can effectively degrade NAMPT protein in different colorectal cancer cells.Moreover,it can significantly inhibit the proliferation of NAPRT knockdown and knockout colorectal cancer cells.The IC50 values(half-maximal inhibitory concentration)for different colorectal cancer cell lines treated with PROTAC-630120 were as follows:RKOshNAPRT～49.03 nmol/L,HCT116shNAPRT～42.28 nmol/L,SW620shNAPRT～55.59 nmol/L,HT29shNAPRT～29.66 nmol/L,SW480shNAPRT～76.17 nmol/L,and SW480sgNAPRT～27.01/34.23 nmol/L.Finally,the drug PROTAC-630120 can inhibit the MAPK-ERK signaling pathway in colorectal cancer cells.Conclusion:The small molecule drug 630120 based on PROTAC that targets NAMPT protein,can inhibit the proliferation of NAPRT knockdown and knockout colorectal cancer cells,so it is expected to become a drug option for adjuvant therapy of cancer patients.