Medicine and Health Sciences Commons^™

Apc-Β-Catenin-Tcf Signaling Silences The Intestinal Guanylin-Gucy2c Tumor Suppressor Axis., Erik S Blomain, Jeffrey A Rappaport, Amanda M Pattison, Babar Bashir, Ellen Caparosa, Jonathan Stem, Adam E Snook, Scott A Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Sporadic colorectal cancer initiates with mutations in APC or its degradation target β-catenin, producing TCF-dependent nuclear transcription driving tumorigenesis. The intestinal epithelial receptor, GUCY2C, with its canonical paracrine hormone guanylin, regulates homeostatic signaling along the crypt-surface axis opposing tumorigenesis. Here, we reveal that expression of the guanylin hormone, but not the GUCY2C receptor, is lost at the earliest stages of transformation in APC-dependent tumors in humans and mice. Hormone loss, which silences GUCY2C signaling, reflects transcriptional repression mediated by mutant APC-β-catenin-TCF programs in the nucleus. These studies support a pathophysiological model of intestinal tumorigenesis in which mutant APC-β-catenin-TCF transcriptional regulation …

Functional Blockade Of E-Selectin In Tumor-Associated Vessels Enhances Anti-Tumor Effect Of Doxorubicin In Breast Cancer, Yoshihiro Morita, Macall Leslie, Hiroyasu Kameyama, Ganesh L R Lokesh, Norihisa Ichimura, Rachel Davis, Natalie Hills, Nafis Hasan, Roy Zhang, Yuji Kondo, David G Gorenstein, David E Volk, Inna Chervoneva, Hallgeir Rui, Takemi Tanaka

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Chemotherapy is a mainstay of treatment for solid tumors. However, little is known about how therapy-induced immune cell infiltration may affect therapy response. We found substantial CD45+ immune cell density adjacent to E-selectin expressing inflamed vessels in doxorubicin (DOX)-treated residual human breast tumors. While CD45 level was significantly elevated in DOX-treated wildtype mice, it remained unchanged in DOX-treated tumors from E-selectin null mice. Similarly, intravenous administration of anti-E-selectin aptamer (ESTA) resulted in a significant reduction in CD45+ immune cell density in DOX-treated residual tumors, which coincided with a delay in tumor growth and lung metastasis in MMTV-pyMT mice. Additionally, both …

Unexpected Cell Type-Dependent Effects Of Autophagy On Polyglutamine Aggregation Revealed By Natural Genetic Variation In C. Elegans., J Alexander-Floyd, S Haroon, M Ying, A A Entezari, C Jaeger, M Vermulst, T Gidalevitz

Department of Pharmacology and Experimental Therapeutics Faculty Papers

BACKGROUND: Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown.

RESULTS: We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to …

Autocatalytic Tissue Polymerization Reaction Mechanism In Colorectal Cancer Development And Growth., Bruce M Boman, Arthur Guetter, Ryan M Boman, Olaf A Runquist

Department of Pharmacology and Experimental Therapeutics Faculty Papers

The goal of our study was to measure the kinetics of human colorectal cancer (CRC) development in order to identify aberrant mechanisms in tissue dynamics and processes that contribute to colon tumorigenesis. The kinetics of tumor development were investigated using age-at-tumor diagnosis (adenomas and CRCs) of familial adenomatous coli (FAP) patients and sporadic CRC patients. Plots of age-at-tumor diagnosis data as a function of age showed a distinct sigmoidal-shaped curve that is characteristic of an autocatalytic reaction. Consequently, we performed logistics function analysis and found an excellent fit (p < 0.05) of the logistic equation to the curves for age-at-tumor diagnoses. These findings indicate that the tissue mechanism that becomes altered in CRC development and growth involves an autocatalytic reaction. We conjecture that colonic epithelium normally functions as a polymer of cells which dynamically maintains itself in a steady state through an autocatalytic polymerization mechanism. Further, in FAP and sporadic CRC patients, mutation in the adenomatous polyposis coli (APC) gene increases autocatalytic tissue polymerization and induces tumor …