Mitophagy in Intestinal Epithelial Cells Triggers Adaptive Immunity during Tumorigenesis.

In colorectal cancer patients, a high density of cytotoxic CD8 T cells in tumors is associated with better prognosis. Using a Stat3 loss-of-function approach in two wnt/β-catenin-dependent autochthonous models of sporadic intestinal tumorigenesis, we unravel a complex intracellular process in intestinal epithelial cells (IECs) that controls the induction of a CD8 T cell based adaptive immune response. Elevated mitophagy in IECs causes iron(II)-accumulation in epithelial lysosomes, in turn, triggering lysosomal membrane permeabilization.

Mesenchymal Cells in Colon Cancer.

Mesenchymal cells in the intestine comprise a variety of cell types of diverse origins, functions, and molecular markers. They provide mechanical and structural support and have important functions during intestinal organogenesis, morphogenesis, and homeostasis. Recent studies of the human transcriptome have revealed their importance in the development of colorectal cancer, and studies from animal models have provided evidence for their roles in the pathogenesis of colitis-associated cancer and sporadic colorectal cancer.

IKKβ acts as a tumor suppressor in cancer-associated fibroblasts during intestinal tumorigenesis.

Cancer-associated fibroblasts (CAFs) comprise one of the most important cell types in the tumor microenvironment. A proinflammatory NF-κB gene signature in CAFs has been suggested to promote tumorigenesis in models of pancreatic and mammary skin cancer. Using an autochthonous model of colitis-associated cancer (CAC) and sporadic cancer, we now provide evidence for a tumor-suppressive function of IKKβ/NF-κB in CAFs.