LAUSR

Kidney injury molecule-1 (KIM-1), also known as hepatitis A virus cellular receptor-1 and T cell Ig mucin-1, is a transmembrane protein, which is not overexpressed in normal kidneys, but is significantly upregulated in damaged kidney tubular epithelial cells in toxic and ischemic acute kidney injury. Of interest, KIM-1 is overexpressed in most cases of renal cell carcinoma (RCC) and in other types of tumors including ovarian clear cell carcinoma and lung cancer. The extracellular domain of KIM-1 can be identified in the urine of patients with RCC and can thus be used as a biomarker for the detection of RCC. This study was carried out to identify a peptide that selectively binds to KIM-1 by screening a phage-displayed peptide library and to use the peptide for the detection of KIM-1-overexpressing tumors in vivo. Biopanning of a phage-displayed peptide library was performed on KIM-1-coated plates. Compared to other phage clones selected after biopanning, a phage clone displaying the CNWMINKEC peptide showed higher binding affinity to KIM-1 as examined by fluorometry and KIM-1-overexpressing 769-P renal tumor cells 1 as examined by ELISA. The CNWMINKEC peptide and a NeutrAvidin/biotin-CNWMINKEC multimer selectively bound to KIM-1 over albumin as examined by fluorometry and to KIM-1-overexpressing 769-P cells and A549 lung tumor cells compared to KIM-1-low expressing HEK293 normal cells when examined by flow cytometry. Co-localization and competition assays using an anti-KIM-1 antibody demonstrated that the binding of the CNWMINKEC peptide to 769-P cells was specifically mediated by KIM-1. Whole-body fluorescence imaging demonstrated selective homing of the CNWMINKEC peptide to KIM-1-overexpressing A498 renal tumor compared to KIM-1-low expressing HepG2 liver tumor in mice. The CNWMINKEC peptide was not cytotoxic to cells and was stable for up to 24 h in the presence of serum. These results suggest that the CNWMINKEC peptide is a promising probe for in vivo imaging and detection of KIM-1-overexpressing tumors. KeywordsIn vivo imaging, kidney injury molecule-1, peptide, phage display, renal cell carcinoma Note: This abstract was not presented at the meeting. Citation Format: Jae-Won Yoon, Soo-woong Lee, Md. Enamul Haque, Rang- Woon Park, Moon-Chang Baek, Dong-Kyu Kim, Sang Kyoon Kim, Byungheon Lee. A phage display identified peptide selectively binds to kidney injury molecule-1(KIM-1) and detects KIM-1-overexpressing tumors in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1147.