Cell-surface markers for colon adenoma and adenocarcinoma

// Kamini Sewda 1 , Domenico Coppola 2 , Steven Enkemann 3 , Binglin Yue 4 , Jongphil Kim 4 , Alexis S. Lopez 5 , Jonathan W. Wojtkowiak 1 , Valerie E. Stark 1 , Brian Morse 6 , David Shibata 7 , Shivakumar Vignesh 8 , David L. Morse 1 1 Department of Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 2 Department of Anatomic Pathology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 3 Department of Molecular Genomics, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 4 Department of Biostatistics and Bioinformatics, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 5 Department of Tissue Core, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 6 Department of Diagnostic Imaging, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA 7 Department of Surgery, University of Tennessee Health Science Center, Memphis, TN 38163, USA 8 Division of Gastroenterology and Hepatology, SUNY Health Sciences Center at Brooklyn, Brooklyn, NY 11203, USA Correspondence to: David L. Morse, email: David.Morse@moffitt.org Keywords: colorectal cancer, cell surface targets, expression profiling, immunohistochemistry, screening Received: October 19, 2015      Accepted: January 24, 2016      Published: February 15, 2016 ABSTRACT Early detection of colorectal cancer (CRC) is crucial for effective treatment. Among CRC screening techniques, optical colonoscopy is widely considered the gold standard. However, it is a costly and invasive procedure with a low rate of compliance. Our long-term goal is to develop molecular imaging agents for the non-invasive detection of CRC by molecular imaging-based colonoscopy using CT, MRI or fluorescence. To achieve this, cell surface targets must be identified and validated. Here, we report the discovery of cell-surface markers that distinguish CRC from surrounding tissues that could be used as molecular imaging targets. Profiling of mRNA expression microarray data from patient tissues including adenoma, adenocarcinoma, and normal gastrointestinal tissues was used to identify potential CRC specific cell-surface markers. Of the identified markers, six were selected for further validation ( CLDN1 , GPR56 , GRM8 , LY6G6D/F , SLCO1B3 and TLR4 ). Protein expression was confirmed by immunohistochemistry of patient tissues. Except for SLCO1B3 , diffuse and low expression was observed for each marker in normal colon tissues. The three markers with the greatest protein overexpression were CLDN1, LY6G6D/F and TLR4, where at least one of these markers was overexpressed in 97% of the CRC samples. GPR56, LY6G6D/F and SLCO1B3 protein expression was significantly correlated with the proximal tumor location and with expression of mismatch repair genes. Marker expression was further validated in CRC cell lines. Hence, three cell-surface markers were discovered that distinguish CRC from surrounding normal tissues. These markers can be used to develop imaging or therapeutic agents targeted to the luminal surface of CRC.