The goal of this application is to define the mechanistic link between obesity, hormone silencing of the tumor suppressor GUCY2C, and colorectal cancer risk;the reversibility of this link;and the utility of oral GUCY2C hormone replacement to mitigate that risk. GUCY2C is the intestinal receptor for the paracrine hormone guanylin in the colorectum, the most commonly lost gene product in sporadic colorectal cancer in mice and humans. GUCY2C regulates intestinal homeostasis, and its silencing by paracrine hormone loss produces epithelial dysfunction characterized by hyperproliferation, increased DNA damage, and reprogramming of cell metabolism, increasing intestinal tumorigenesis. Unexpectedly, preliminary studies revealed that guanylin expression in colon is eliminated by obesity in mice and humans. Guanylin expression appears to be reversibly modulated by ingested calories, rather than by the endocrine, adipokine or inflammatory milieu associated with obesity. These observations suggest a model of cancer risk in which ingested calories contributing to obesity recapitulate established mechanisms underlying sporadic colorectal cancer, by suppressing guanylin expression, silencing the GUCY2C tumor suppressor and disrupting epithelial homeostasis, increasing tumorigenesis. In the present application, the first aim will test the hypothesis that obesity induces epithelial dysfunction and tumorigenesis by suppressing guanylin expression and silencing GUCY2C. These studies will establish suppression of guanylin expression as a critical mechanistic link between diet, obesity, and cancer risk.
The second aim will define the contribution of reversible calorie- dependent modulation of guanylin expression to epithelial dysfunction in obesity. These studies will expand the current paradigm of cancer risk beyond obesity and its associated endocrine milieu, to include the role of ingested calories as a reversible risk factor linking obesity and cancer. Finally, the third aim will explore the utility of oral GUCY2C ligand supplementation to prevent obesity-induced epithelial dysfunction and colorectal cancer. These studies will establish the utility of oral GUCY2C ligand replacement as a chemopreventive strategy to mitigate obesity-related cancer risk. Together, these studies will define one concrete mechanism linking obesity to cancer, serving as a bridge between identification of risk factors (obesity, diet, ingested calories) and the molecular biology of cancer development through silencing of the GUCY2C tumor suppressor. Understanding these mechanisms underlying cancer risk posed by obesity will provide new strategies for countering these risks, including calorie restriction and oral hormone replacement. The potential for immediate translation of these results to mitigate colorectal cancer risk in obese patients can be appreciated in the context of the imminent regulatory approval of oral GUCY2C ligands to treat constipation.
Here we explore the relationship between obesity, cancer, and hormones regulating the intestinal tumor suppressor GUCY2C. We propose that obesity increases colorectal cancer risk by suppressing the expression of those hormones and silencing GUCY2C, an effect which can be reversed by dietary calorie restriction or oral GUCY2C hormone replacement therapy.
|Blomain, Erik S; Merlino, Dante J; Pattison, Amanda M et al. (2016) Guanylyl Cyclase C Hormone Axis at the Intersection of Obesity and Colorectal Cancer. Mol Pharmacol 90:199-204|
|Lin, Jieru E; Colon-Gonzalez, Francheska; Blomain, Erik et al. (2016) Obesity-Induced Colorectal Cancer Is Driven by Caloric Silencing of the Guanylin-GUCY2C Paracrine Signaling Axis. Cancer Res 76:339-46|
|Blomain, Erik S; Waldman, Scott A (2016) Does obesity promote the development of colorectal cancer? Expert Rev Anticancer Ther 16:465-7|
|Waldman, S A; Terzic, A (2016) Bioinnovation Enterprise: An engine driving breakthrough therapies. Clin Pharmacol Ther 99:8-13|
|Waldman, S A; Terzic, A (2016) Big Data Transforms Discovery-Utilization Therapeutics Continuum. Clin Pharmacol Ther 99:250-4|
|Pattison, Amanda M; Blomain, Erik S; Merlino, Dante J et al. (2016) Intestinal Enteroids Model Guanylate Cyclase C-Dependent Secretion Induced by Heat-Stable Enterotoxins. Infect Immun 84:3083-91|
|Marszalowicz, Glen P; Snook, Adam E; Magee, Michael S et al. (2014) GUCY2C lysosomotropic endocytosis delivers immunotoxin therapy to metastatic colorectal cancer. Oncotarget 5:9460-71|
|Waldman, S A; Terzic, A (2014) Managing the innovation supply chain to maximize personalized medicine. Clin Pharmacol Ther 95:113-8|
|Snook, Adam E; Magee, Michael S; Schulz, Stephanie et al. (2014) Selective antigen-specific CD4(+) T-cell, but not CD8(+) T- or B-cell, tolerance corrupts cancer immunotherapy. Eur J Immunol 44:1956-66|
|Wilson, Chantell; Lin, Jieru E; Li, Peng et al. (2014) The paracrine hormone for the GUCY2C tumor suppressor, guanylin, is universally lost in colorectal cancer. Cancer Epidemiol Biomarkers Prev 23:2328-37|
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