Epithelial Hypoxia-Inducible Factor 2α Facilitates the Progression of Colon Tumors through Recruiting Neutrophils

D Triner, X Xue, AJ Schwartz, I Jung… - … and Cellular Biology, 2017 - Taylor & Francis
D Triner, X Xue, AJ Schwartz, I Jung, JA Colacino, YM Shah
Molecular and Cellular Biology, 2017Taylor & Francis
Inflammation is a significant risk factor for colon cancer. Recent work has demonstrated
essential roles for several infiltrating immune populations in the metaplastic progression
following inflammation. Hypoxia and stabilization of hypoxia-inducible factors (HIFs) are
hallmark features of inflammation and solid tumors. Previously, we demonstrated an
important role for tumor epithelial HIF-2 α in colon tumors; however, the function of epithelial
HIF-2 α as a critical link in the progression of inflammation to cancer has not been …
Abstract
Inflammation is a significant risk factor for colon cancer. Recent work has demonstrated essential roles for several infiltrating immune populations in the metaplastic progression following inflammation. Hypoxia and stabilization of hypoxia-inducible factors (HIFs) are hallmark features of inflammation and solid tumors. Previously, we demonstrated an important role for tumor epithelial HIF-2α in colon tumors; however, the function of epithelial HIF-2α as a critical link in the progression of inflammation to cancer has not been elucidated. In colitis-associated colon cancer models, epithelial HIF-2α was essential in tumor growth. Concurrently, epithelial disruption of HIF-2α significantly decreased neutrophils in the colon tumor microenvironment. Intestinal epithelial HIF-2α-overexpressing mice demonstrated that neutrophil recruitment was a direct response to increased epithelial HIF-2α signaling. High-throughput RNA sequencing (RNA-seq) analysis of HIF-2α-overexpressing mice in conjunction with data mining from the Cancer Genome Atlas showed that the neutrophil chemokine CXCL1 gene was highly upregulated in colon tumor epithelium in a HIF-2α-dependent manner. Using selective peptide inhibitors of the CXCL1-CXCR2 signaling axis identified HIF-2α-dependent neutrophil recruitment as an essential mechanism to increase colon carcinogenesis. These studies demonstrate that HIF-2α is a novel regulator of neutrophil recruitment to colon tumors and that it is essential in shaping the protumorigenic inflammatory microenvironment in colon cancer.
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