Medicine and Health Sciences Commons^™

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 …

Molecular Staging Of Node Negative Patients With Colorectal Cancer., Terry Hyslop, Scott A Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Metastatic disease is the principle cause of death from colorectal cancer. In that context, the most significant indicator of overall survival and therapeutic response to adjuvant chemotherapy is the presence of metastatic tumor cells in regional lymph nodes. Although histopathologic analysis of lymph nodes is central to all colorectal cancer staging paradigms, its prognostic and predictive value is limited. Indeed, about 30% of patients with histopathology-negative lymph nodes (pN0) die from metastatic disease, reflected by microscopic lymph node metastases that are overlooked by standard techniques. These unrecognized tumor cells are especially important when considering racial disparities in outcomes in colorectal …

Phosphorylation Of Vasodilator-Stimulated Phosphoprotein Ser239 Suppresses Filopodia And Invadopodia In Colon Cancer., David S Zuzga, Joshua Pelta-Heller, Peng Li, Alessandro Bombonati, Scott A Waldman, Giovanni Mario Pitari

Department of Pharmacology and Experimental Therapeutics Faculty Papers

In colorectal cancer, the antitumorigenic guanylyl cyclase C (GCC) signalome is defective reflecting ligand deprivation from downregulation of endogenous hormone expression. Although the proximal intracellular mediators of that signal transduction system, including cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase (PKG), are well characterized, the functional significance of its distal effectors remain vague. Dysregulation of ligand-dependent GCC signaling through vasodilator-stimulated phosphoprotein (VASP), an actin-binding protein implicated in membrane protrusion dynamics, drastically reduced cGMP-dependent VASP phosphorylation levels in colorectal tumors from patients. Restoration of cGMP-dependent VASP phosphorylation by GCC agonists suppressed the number and length of locomotory (filopodia) and invasive (invadopodia) …

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 …

Enterotoxin Preconditioning Restores Calcium-Sensing Receptor-Mediated Cytostasis In Colon Cancer Cells, Giovanni Mario Pitari, Jieru E. Lin, Fawad J. Shah, Wilhelm J. Lubbe, David Zuzga, Peng Li, Stephanie Schulz, Scott A Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Guanylyl cyclase C (GCC), the receptor for diarrheagenic bacterial heat-stable enterotoxins (STs), inhibits colorectal cancer cell proliferation by co-opting Ca(2+) as the intracellular messenger. Similarly, extracellular Ca(2+) (Ca(2+)(o)) opposes proliferation and induces terminal differentiation in intestinal epithelial cells. In that context, human colon cancer cells develop a phenotype characterized by insensitivity to cytostasis imposed by Ca(2+)(o). Here, preconditioning with ST, mediated by GCC signaling through cyclic nucleotide-gated channels, restored Ca(2+)(o)-dependent cytostasis, reflecting posttranscriptional regulation of calcium-sensing receptors (CaRs). ST-induced GCC signaling deployed CaRs to the surface of human colon cancer cells, whereas elimination of GCC signaling in mice nearly abolished …