The Role of CCL11 in Inflammatory and Sporadic Colorectal Cancer.

Veterans Health Administration, Decatur PA

Investigators

Abstract

With more than 3 million Americans affected, inflammatory bowel disease (IBD) causes significant morbidity and can progress to colorectal cancer (CRC). There are two main forms of IBD: ulcerative colitis (UC) and Crohn’s disease, and the associated abnormal immune response continues to be investigated with the hope that new therapeutics can be developed. CRC is the 3rd most common cancer and 2nd leading cause of death in men and women combined and colitis-associated cancer (CAC) is a subset of CRC. Sporadic CRC is also a major clinical problem in Veterans. We have previously shown in a prospectively collected cohort of adult UC patients, CCL11, classically described as an eosinophil chemoattractant, was the only analyte increased in both serum and tissue compared to non-IBD controls. Ccl11-deficient mice have been shown to be protected from colitis in an acute dextran sulfate sodium (DSS)-induced colitis model. However, acute colitis studies in mice lacking eosinophils (including ΔdblGATA mice) have been mixed, suggesting it is not simply just decreased tissue eosinophil infiltration leading to improvement in colitis. We have reported that Ccl11-deficient mice exhibit decreased tumor number and burden in the azoxymethane (AOM)-DSS CAC model. CCL11 has also been shown to be increased in sporadic CRC. We have now found that 1) mice with epithelial cell-specific loss of CCL11 (Ccl11∆GIepi) exhibit decreased tumor number and burden in the AOM-DSS model; 2) tumors from CDX2P-CreERT2Apcfl/fl mice (CRC model due to altered adenomatous polyposis coli (Apc) expression) exhibit increased CCL11 expression; 3) epithelial cell-specific loss of CCL11 in CDX2P-CreERT2Apcfl/flCcl11fl/fl mice leads to decreased tumor number and burden; 4) tumorigenesis is not altered in ΔdblGATA mice in the AOM-DSS model or in CDX2P- CreERT2Apcfl/flΔdblGATA mice, 5) human colonoids express receptors for CCL11; 6) recombinant CCL11 (rCCL11) leads to decreased colonic epithelial wound restitution; and 7) tumors from Ccl11∆GIepi mice exhibit decreased levels of pERK1/2 indicative of MAPK activation, which is frequently implicated in CRC development. We propose to investigate the role of epithelial-derived CCL11 in oncogenic epithelial dysfunction in models of CAC and sporadic CRC. We will use Veteran patient-derived colon tissues and organoids to validate our animal studies and develop rationales for future human studies. Our Hypothesis is: CCL11 dysregulates epithelial function and supports carcinogenesis via MAPK/ERK signaling in inflammatory and sporadic colon cancer. The Specific Aims are: 1. To test the hypothesis that CCL11 activates MAPK/ERK signaling predisposing to CAC via epithelial dysfunction. Ccl11∆GIepi and ΔdblGATA mice exposed to AOM-DSS will be used to test the hypothesis that CCL11 leads to epithelial dysfunction via MAPK/ERK signaling in murine models and organoids. 2. To test the hypothesis that CCL11 signaling promotes sporadic CRC driven by somatic mutations via dysregulating epithelial function and promoting oncogenic signaling. CDX2P- CreERT2Apcfl/fl and CDX2P-CreERT2Apcfl/flCcl11fl/fl mice will be used to test the hypothesis that epithelial CCL11 promotes tumor development by assessing tumor number and size and epithelial function. Epithelial function and oncogenic signaling will be assessed in murine organoids and HCT116 cells exposed to cytokine cocktails, rCCL11, an anti-CCL11 antibody, and with CCL11 receptor knockdown 3. To test the hypothesis that CCL11 signaling dysregulates epithelial function and promotes oncogenic signaling in tissues and patient- derived colon organoids (PDCOs) from Veterans. CCL11 is increased in IBD patients, CAC, and CRC. We will compare genomic alterations and transcriptional profiles in normal, IBD, CAC, and CRC samples to CCL11 expression and epithelial function and oncogenic signaling pathways. Epithelial function and oncogenic signaling will be assessed in PDCOs exposed to cytokine cocktails, rCCL11, an anti-CCL11 antibody, and with CCL11 receptor knockdown. These studies will lead to new insights that could identify molecular-based approaches to improve patient risk stratification and identify new treatment strategies based on modulation of CCL11 signaling.