CCL20 induces colorectal cancer neoplastic epithelial cell proliferation, migration, and further CCL20 production through autocrine HGF-c-Met and MSP-MSPR signaling pathways.

Bisweswar Nandi,Jonathan Pastrana Del Valle,Jason S Gold,Mehmet K Samur,Nikhil C Munshi,Rao H Prabhala,Allison J Gibbons

doi:10.18632/oncotarget.28131

Abstract

CCL20-CCR6 interactions promote colorectal cancer through direct effects on neoplastic epithelial cells and through modulating the tumor microenvironment. The mechanism of these effects on neoplastic epithelial cells is poorly understood. This study demonstrates that CCL20 induces secretion of hepatocyte growth factor (HGF) and phosphorylation of HGF’s cognate receptor c-Met in HT29 and HCT116 colorectal cancer cell lines both in concentration- and time-dependent manners. Similar to CCL20, HGF induces migration, autofeedback CCL20 secretion, and ERK1/2 phosphorylation in the colon cancer cells. CCL20-dependent ERK1/2 phosphorylation is blocked by HGF inhibition, and CCL20-dependent migration and CCL20 secretion are blocked by inhibition of HGF or ERK. Interestingly, unlike CCL20, HGF does not induce proliferation of colon cancer cells, and CCL20-dependent cell proliferation is not blocked by direct HGF inhibition. CCL20-dependent proliferation, however, is blocked by the multi-tyrosine kinase inhibitor crizotinib. Exploring this effect, it was found that CCL20 also induces production of MSP and phosphorylation of MSP’s receptor MSPR by the colorectal cancer cells. CCL20-dependent cell proliferation is inhibited by directly blocking MSP-MSPR interactions. Thus, CCL20-mediated migration and CCL20 secretion are regulated through a pathway involving HGF, c-Met, and ERK, while CCL20-mediated proliferation is instead regulated through MSP and its receptor MSPR.

Highlights

The tumor microenvironment contains a rich signaling network of soluble factors including cytokines, chemokines, growth factors, and cellular metabolites
To further corroborate a link of C-C chemokine ligand 20 (CCL20) exposure to hepatocyte growth factor (HGF) secretion in colorectal cancer, a correlative analysis was performed between gene expression of CCL20 and HGF as well as between CCL20’s receptor, C-C chemokine receptor 6 (CCR6), and HGF and using data from human colorectal cancers collected by the Cancer Genome Atlas (TCGA) (Figure 1D)
There was a weak negative correlation between CCL20 and HGF (R2 = 0.01, Pearson’s r = –0.12). These results support a link between CCL20-CCR6 signaling and HGF secretion in human colorectal cancer but suggest that this might be regulated at the level of CCR6 rather than CCL20. (CCL20 and CCR6 expression were strongly correlated (R2 = 0.04, Pearson’s r = 0.21, Supplementary Figure 2).) To assess whether CCL20 stimulation of colorectal cancer cells induces activation of HGF’s receptor, c-Met, we measured expression of c-Met and phosphorylated c-Met by Western blots and found CCL20 to induce c-Met phosphorylation after CCL20 exposure in both a concentration-dependent (Figure 1E) and time-dependent manner (Figure 1F) in both HT-29 and HCT116

Summary

Introduction

The tumor microenvironment contains a rich signaling network of soluble factors including cytokines, chemokines, growth factors, and cellular metabolites. These factors mediate crosstalk between neoplastic epithelial cells and various stromal cells including leukocytes, fibroblasts, stem cells, endothelial cells, and pericytes. Chemokines are a family of small signaling proteins with shared structural characteristics. They are involved in the development and progression of many cancer types, www.oncotarget.com including colorectal cancer. Expression of the C-C chemokine CCL20, known as macrophage inflammatory protein-3 α (MIP-3 α) and liver activation regulated chemokine (LARC), as well as its receptor CCR6 have been observed in several malignancies including colorectal cancer. Several animal studies have confirmed the importance of these molecules in this disease [1, 2, 7,8,9,10,11]

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