Although breast cancer stem cells (BCSCs) display plasticity transitioning between quiescent mesenchymal-like (M) and proliferative epithelial-like (E) states, how this plasticity is regulated by metabolic or oxidative stress remains poorly understood. Here, we show that M- and E-BCSCs rely on distinct metabolic pathways and display markedly different sensitivities to inhibitors of glycolysis and redox metabolism. Metabolic or oxidative stress generated by 2DG, HO, or hypoxia promotes the transition of ROS M-BCSCs to a ROS E-state. This transition is reversed by N-acetylcysteine and mediated by activation of the AMPK-HIF1α axis. Moreover, E-BCSCs exhibit robust NRF2-mediated antioxidant responses, rendering them vulnerable to ROS-induced differentiation and cytotoxicity following suppression of NRF2 or downstream thioredoxin (TXN) and glutathione (GSH) antioxidant pathways. Co-inhibition of glycolysis and TXN and GSH pathways suppresses tumor growth, tumor-initiating potential, and metastasis by eliminating both M- and E-BCSCs. Exploiting metabolic vulnerabilities of distinct BCSC states provides a novel therapeutic approach targeting this critical tumor cell population.

Yes-associated protein 1 (YAP1) is a transcriptional coactivator in the Hippo signaling pathway. Increased YAP1- activity promotes the growth of tumors, including that of colorectal cancer (CRC). Verteporfin, a drug that enhances phototherapy to treat neovascular macular degeneration, is an inhibitor of YAP1. Here, we found that verteporfin inhibited tumor growth independently of its effects on YAP1 or the related protein TAZ in genetic or chemical-induced mouse models of CRC, in patient-derived xenografts and in enteroid models of CRC. Instead, verteporfin exhibited in vivo selectivity for killing tumor cells in part by impairing the global clearance of high molecular weight oligomerized proteins, particularly p62 (a sequestrome involved in autophagy) and STAT3 (a transcription factor). Verteporfin inhibited cytokine-induced STAT3 activity and cell proliferation and reduced the viabilty of cultured CRC cells. Although verteporfin accumulated to a greater extent in normal cells than in tumor cells in vivo, experiments with cultured cells indicated that the normal cells efficiently cleared verteporfin-induced protein oligomers through autophagic and proteasomal pathways. Culturing CRC cells in hypoxic or nutrient-deprived conditions (modeling a typical CRC microenvironment) impaired the clearance of protein oligomers and resulted in cell death; whereas culturing cells in normoxic or glucose-replete conditions protected cell viability and proliferation in the presence of verteporfin. Furthermore, verteporfin suppressed the proliferation of other cancer cell lines even in the absence of YAP1, suggesting that verteporfin may be effective against multiple types of solid cancers.

Summary Dietary iron intake and systemic iron balance are implicated in colorectal cancer (CRC) development, but the means by which iron contributes to CRC are unclear. Gene expression and functional studies demonstrated that the cellular iron importer, divalent metal transporter 1 (DMT1), is highly expressed in CRC through hypoxia inducible factor 2α-dependent transcription. Colon-specific Dmt1 disruption resulted in a tumor-selective inhibitory effect of proliferation in mouse colon tumor models. Proteomic and genomic analysis identified an iron-regulated signaling axis mediated by cyclin dependent kinase 1 (CDK1), JAK1 and STAT3 in CRC progression. A pharmacological inhibitor of DMT1 antagonized the ability of iron to promote tumor growth in a CRC mouse model and a patient-derived CRC enteroid orthotopic model. Our studies implicate a growth-promoting signaling network instigated by elevated intracellular iron levels in tumorigenesis, offering molecular insights into how a key dietary component may contribute to CRC.

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Background & Aims: Neutrophils are among the most prevalent immune cells in the microenvironment of colon tumors, are believed to promote growth of colon tumors, and their numbers correlate with outcomes of patients with colon cancer. Trials of inhibitors of neutrophil

Microfold cells (M-cells) are specialized cells of the intestine that sample luminal microbiota and dietary antigens to educate the immune cells of the intestinal lymphoid follicles. The function of M-cells in systemic inflammatory responses are still unclear. Here we show that epithelial non-canonical NFkB signaling mediated by NFkB-inducing kinase (NIK) is highly active in intestinal lymphoid follicles, and is required for M-cell maintenance. Intestinal NIK signaling modulates M-cell differentiation and elicits both local and systemic IL-17A and IgA production. Importantly, intestinal NIK signaling is active in mouse models of colitis and patients with inflammatory bowel diseases; meanwhile, constitutive NIK signaling increases the susceptibility to inflammatory injury by inducing ectopic M-cell differentiation and a chronic increase of IL-17A. Our work thus defines an important function of non-canonical NFkB and M-cells in immune homeostasis, inflammation and polymicrobial sepsis.

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 hypoxiainducible factors (HIFs) are hallmark features of inflammation and solid tumors. Previously, we demonstrated an important role for tumor epithelial HIF-2␣ in colon tumors; however, the function of epithelial HIF-2␣ as a critical link in the progression of inflammation to cancer has not been elucidated. In colitis-associated colon cancer models, epithelial HIF-2␣ was essential in tumor growth. Concurrently, epithelial disruption of HIF-2␣ significantly decreased neutrophils in the colon tumor microenvironment. Intestinal epithelial HIF-2␣-overexpressing mice demonstrated that neutrophil recruitment was a direct response to increased epithelial HIF-2␣ signaling. High-throughput RNA sequencing (RNA-seq) analysis of HIF-2␣-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-2␣-dependent manner. Using selective peptide inhibitors of the CXCL1-CXCR2 signaling axis identified HIF-2␣-dependent neutrophil recruitment as an essential mechanism to increase colon carcinogenesis. These studies demonstrate that HIF-2␣ is a novel regulator of neutrophil recruitment to colon tumors and that it is essential in shaping the protumorigenic inflammatory microenvironment in colon cancer.KEYWORDS HIF-2␣, inflammation, colon cancer, cancer, colon, hypoxia, neutrophils C olon cancer remains a significant public health concern and is the second leading cause of cancer-associated deaths in the United States (1). Patients with chronic inflammation associated with inflammatory bowel disease (IBD), comprising ulcerative colitis and Crohn's disease, are at an increased lifetime risk of developing colon cancer; these tumors are termed colitis-associated cancers (CAC) (2). The genetic changes of sporadic colon cancer have been well defined, and a comprehensive genetic analysis of CAC was recently reported (3). In contrast to sporadic colon cancer, CAC are associated with early loss of the TP53 tumor suppressor and less frequent inactivation of adenomatous polyposis coli (APC) (4). Inflammation is an important component of the progression of sporadic cancer, and the inflammatory response is essential in the initiation and progression of CAC (5). The precise mechanisms that initiate the protumorigenic response following inflammation remain unknown.Hypoxia is a characteristic feature of IBD and nearly all solid tumors, including those of the colon (6). Hypoxia promotes activation of the hypoxia-inducible factors (HIFs). HIFs consist of a heterodimer of an O 2 -labile ␣-subunit (HIF-1␣, HIF-2␣, and HIF-3␣) and an O 2 -stable ␤-subunit (ARNT) (7). HIFs regulate transcription of target genes that mediate cellular responses to hypoxic microenvironments. HIFs are also essenti...

Myc-associated zinc finger (MAZ) is a transcription factor highly upregulated in chronic inflammatory disease and several human cancers. In the present study, we found that MAZ protein is highly expressed in human ulcerative colitis and colon cancer. However, the precise role for MAZ in the progression of colitis and colon cancer is not well defined. To determine the function of MAZ, a novel mouse model of intestinal epithelial cell-specific MAZ overexpression was generated. Expression of MAZ in intestinal epithelial cells was sufficient to enhance inflammatory injury in two complementary models of colitis. Moreover, MAZ expression increased tumorigenesis in an model of inflammation-induced colon cancer and was important for growth of human colon cancer cell lines and Mechanistically, MAZ is critical in the regulation of oncogenic STAT3 signaling. MAZ-expressing mice have enhanced STAT3 activation in the acute response to colitis. Moreover, MAZ was essential for cytokine- and bacterium-induced STAT3 signaling in colon cancer cells. Furthermore, we show that STAT3 is essential for MAZ-induced colon tumorigenesis using a chemical inhibitor. These data indicate an important functional role for MAZ in the inflammatory progression of colon cancer through regulation of STAT3 signaling and suggest that MAZ is a potential therapeutic target to dampen STAT3 signaling in colon cancer.