ISG Winter Meeting 2015
First Prize Basic Science
St. Vincent’s University Hospital, Dublin
Preclinical investigation of the prognostic role of KHSRP in colorectal cancer: balancing the tumor and the immune microenvironment
Francesco Caiazza, Zaid Heetun, Louise Elliott, Miriam Tosetto, Robert Power, Blathnaid Nolan, Glen A. Doherty, Elizabeth J. Ryan
Centre for Colorectal Disease, St. Vincent’s University Hospital; School of Medicine and Medical Science, University College Dublin
Inflammation is a key driver of the initiation and progression of Colorectal Cancer (CRC). Post-transcriptional regulation of the 3’ untranslated region (UTR) is a powerful regulatory process that determines the rate of protein translation from mRNA. Regulatory elements targeting the 3’ UTR such as the RNA-binding protein, K-homology splicing regulatory protein (KHSRP) can both dramatically alter the immune response and regulate cell cycle, and therefore this may be a good biomarker or therapeutic target for the control of cancer associated inflammation.
Our aim was to determine if KHSRP plays a role in establishing the inflammatory environment of CRC.
KHSRP transcript and protein expression in CRC and Inflammatory Bowel Disease (IBD) was analyzed in publicly available databases, and in tissue samples by western blot and Immunohistochemistry. Functional analysis of KHSRP was performed by siRNA-mediated knockdown of KHSRP in 2 colorectal cancer cell lines.
In silico analysis of 17 different patient cohorts showed an elevated expression of KHSRP mRNA in CRC patients.,This was confirmed at the protein level by Western blot analysis of 19 patients in both early stage and metastatic CRC. IHC analysis showed that KHSRP was expressed in both the epithelial and stromal compartments of CRC and IBD patients, however for the latter case expression of KHSRP increased specifically in the stroma of dysplastic tissue. Furthermore, KHSRP expression predicted decreased 5-year relapse-free survival in a cohort of 750 patients with stage I-IV CRC Using siRNA in two CRC cell lines we showed that KHSRP is required for secretion of the pro-angiogenic cytokines IL-8 and VEGF, whereas KHSRP reduces secretion of RANTES, a T-cell chemoattractant. Furthermore, cell proliferation, clonogenic potential and three-dimensional growth of CRC cells in extracellular matrix are also enhanced by KHSRP, through regulation of cell cycle.
Our data suggests a role for KHSRP in creating a tumor-permissive microenvironment in CRC.