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Updated: Apr 17, 2026
A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer
Published on: July 6, 2017
A novel immunotoxin - rCCK8PE38 targeting of CCK-R overexpressed colon cancers
Shiqi Gao1, Jie Song, Fengge Chen
1Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University , Changchun , PR China .
Background:
Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, such as pancreatic, colon and gastric cancers. Previous studies have shown that the specific receptor-binding property of CCK for CCK receptors (CCKRs) can be exploited to produce immunotoxins (ITs) that target cancer cells overexpressing CCK receptors.
Purpose:
Construct a new IT-targeting CCKR-overexpressing colon cancers.
Methods:
To construct the CCKR-targeted IT, a reverse CCK8 peptide was fused with a modified 38-kDa truncated form of the Pseudomonas exotoxin (PE38KDEL). An efficient immunoaffinity purification procedure was used to produce a PE38-based IT. Several analyses, including CCK8 competition and indirect immunofluorescence assays, were performed to confirm the interaction between rCCK8 and CCKR. After cytotoxic assays on several cell lines, the anti-tumor activity of the new IT was detected in nude mice.
Results:
The rCCK8PE38 IT showed specific cytotoxicity for two colon cancer cell lines and one gastric cancer cell line. After purification, 18-26 mg of pure rCCK8PE38 per 1 L of culture was obtained. Purified rCCK8PE38 showed high cytotoxicity in colon cancer cell lines with IC50 values of 0.8-3.5 ng/mL. The results of the CCK8 competition and indirect immunofluorescence assays showed that rCCK8 had a specific interaction with CCKR. Nude mice inoculated with HCT-8 tumor xenografts were treated with rCCK8PE38, which efficiently decreased the tumor size in those mice.
Conclusions And Discussion:
All of these data suggest that rCCK8PE38 has potential as a new immunotherapy agent. Furthermore, the results of this study further support the high value of the immunoaffinity method for IT purification procedures.
