Medicine and Health Sciences Commons^™

Guanylyl Cyclase C As A Diagnostic And Therapeutic Target In Colorectal Cancer, Adi Caspi, Ariana A. Entezari, Madison Crutcher, Adam E. Snook, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Colorectal cancer remains a major cause of mortality in the USA, despite advances in prevention and screening. Existing therapies focus primarily on generic treatment such as surgical intervention and chemotherapy, depending on disease severity. As personalized medicine and targeted molecular oncology continue to develop as promising treatment avenues, there has emerged a need for effective targets and biomarkers of colorectal cancer. The transmembrane receptor guanylyl cyclase C (GUCY2C) regulates intestinal homeostasis and has emerged as a tumor suppressor. Further, it is universally expressed in advanced metastatic colorectal tumors, as well as other cancer types that arise through intestinal metaplasia. In …

Split Tolerance Permits Safe Ad5-Gucy2c-Padre Vaccine-Induced T-Cell Responses In Colon Cancer Patients., Adam E. Snook, Trevor R. Baybutt, Bo Xiang, Tara S. Abraham, John C. Flickinger, Terry Hyslop, Tingting Zhan, Walter K. Kraft, Takami Sato, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Background: The colorectal cancer antigen GUCY2C exhibits unique split tolerance, evoking antigen-specific CD8+, but not CD4+, T-cell responses that deliver anti-tumor immunity without autoimmunity in mice. Here, the cancer vaccine Ad5-GUCY2C-PADRE was evaluated in a first-in-man phase I clinical study of patients with early-stage colorectal cancer to assess its safety and immunological efficacy.

Methods: Ten patients with surgically-resected stage I or stage II (pN0) colon cancer received a single intramuscular injection of 1011 viral particles (vp) of Ad5-GUCY2C-PADRE. Safety assessment and immunomonitoring were carried out for 6 months following immunization. This trial employed continual monitoring of both efficacy and toxicity …

Guanylate Cyclase C As A Target For Prevention, Detection, And Therapy In Colorectal Cancer., Allison A. Aka, Jeff A. Rappaport, Amanda M. Pattison, Takami Sato, Adam E. Snook, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

INTRODUCTION: Colorectal cancer remains the second leading cause of cancer death in the United States, and new strategies to prevent, detect, and treat the disease are needed. The receptor, guanylate cyclase C (GUCY2C), a tumor suppressor expressed by the intestinal epithelium, has emerged as a promising target. Areas covered: This review outlines the role of GUCY2C in tumorigenesis, and steps to translate GUCY2C-targeting schemes to the clinic. Endogenous GUCY2C-activating ligands disappear early in tumorigenesis, silencing its signaling axis and enabling transformation. Pre-clinical models support GUCY2C ligand supplementation as a novel disease prevention paradigm. With the recent FDA approval of the …

Gucy2c Lysosomotropic Endocytosis Delivers Immunotoxin Therapy To Metastatic Colorectal Cancer., Glen P Marszalowicz, Adam E. Snook, Michael Sullivan Magee, Dante Merlino, Lisa D Berman-Booty, Scott A Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

The emergence of targeted cancer therapy has been limited by the paucity of determinants which are tumor-specific and generally associated with disease, and have cell dynamics which effectively deploy cytotoxic payloads. Guanylyl cyclase C (GUCY2C) may be ideal for targeting because it is normally expressed only in insulated barrier compartments, including intestine and brain, but over-expressed by systemic metastatic colorectal tumors. Here, we reveal that GUCY2C rapidly internalizes from the cell surface to lysosomes in intestinal and colorectal cancer cells. Endocytosis is independent of ligand binding and receptor activation, and is mediated by clathrin. This mechanism suggests a design for …

Molecular Staging Individualizing Cancer Management, Alex Mejia, Stephanie Schulz, Terry Hyslop, David S. Weinberg, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Although the most important prognostic and predictive marker in colorectal cancer is tumor cells in lymph nodes, ∼30% of patients who are node-negative die from occult metastases. Molecular staging employing specific markers and sensitive detection technologies has emerged as a powerful platform to assess prognosis in node-negative colon cancer. Integrating molecular staging into algorithms that individualize patient management will require validation and the definition of relationships between occult tumor cells, prognosis, and responses to chemotherapy. J. Surg. Oncol. 2012; 105:468-474. © 2012 Wiley Periodicals, Inc.

Copyright © 2012 Wiley Periodicals, Inc.

Molecular Staging Estimates Occult Tumor Burden In Colorectal Cancer, Alex Mejia, Stephanie Schulz, Terry Hyslop, David S. Weinberg, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Tumor cells in regional lymph nodes are a key prognostic marker of survival and predictive marker of response to adjuvant chemotherapy in colorectal cancer. However, clinicopathologic techniques to detect lymph node metastases remain imperfect, and ~30% of patients with lymph nodes negative by histology (pN0) develop recurrent disease, reflecting occult metastases that escape detection. These observations underscore an unmet clinical need for accurate approaches to identify occult nodal metastases in colorectal cancer patients. GUCY2C is a receptor whose expression normally is restricted to intestinal epithelial cells, but is universally over-expressed by colorectal cancer cells. A prospective, multicenter, blinded clinical trial …