Colorectal carcinoma, the second most common cancer in men and women in the U.S., is newly diagnosed in 150,000 persons each year. Chemoprevention through cyclooxygenase-2 (COX-2) specific NSAIDs is being proposed as a viable means of reducing the incidence of colorectal polyps, the precursors of colon cancer, and of progression from polyp to cancer. COX-2 expression is found in stromal intestinal myofibroblasts (IMFs) in premalignant colorectal adenomatous polyps and there is global activation (alpha smooth muscle actin expression) in these lamina propria stromal cells. The long term goal of this research is to explore the hypothesis that, in colorectal polyp IMFs, signaling via reactive oxygen species (ROS) and transforming growth factor beta (TGF() control both the activated phenotype and the expression of COX-2 at transcriptional and post-transcriptional levels. Using molecular techniques including Northern and Western analyses, RT-PCR, siRNA knockdown, confocal microscopy of single cell cytoplasm/nuclear molecule translocation and ROS generation, chromatin immunoprecipitation and analysis, and immunohistochemistry and confocal microscopy of human archival normal colon, polyp and cancer sections and primary isolated IMFs, we will address the following specific aims: 1) Identify the mechanisms responsible for ROS-mediated COX-2 transcriptional activation in isolated IMFs, 2) Establish which ROS activated signaling pathways mediate COX-2 mRNA stabilization in isolated IMFs, 3) Identify the mechanisms by which TGFbeta induces COX-2 expression in isolated IMFs and 4) Investigate and clarify how ROS and TGFbeta influence mesenchymal/epithelial interactions in a co-culture models of normal, polyp and carcinoma epithelial and stromal (IMF) cells. These studies will identify key pathways that mediate stromal activation early in the process of colorectal carcinogenesis and create new targets for the development of preventive strategies that will prevent progression to carcinoma.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Gastrointestinal Cell and Molecular Biology Study Section (GCMB)
Program Officer
Hamilton, Frank A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Texas Medical Br Galveston
Internal Medicine/Medicine
Schools of Medicine
United States
Zip Code
Mifflin, R C; Pinchuk, I V; Saada, J I et al. (2011) Intestinal myofibroblasts: targets for stem cell therapy. Am J Physiol Gastrointest Liver Physiol 300:G684-96
Pinchuk, Irina V; Beswick, Ellen J; Saada, Jamal I et al. (2011) Human colonic myofibroblasts promote expansion of CD4+ CD25high Foxp3+ regulatory T cells. Gastroenterology 140:2019-30
Powell, D W; Pinchuk, I V; Saada, J I et al. (2011) Mesenchymal cells of the intestinal lamina propria. Annu Rev Physiol 73:213-37
Pinchuk, I V; Mifflin, R C; Saada, J I et al. (2010) Intestinal mesenchymal cells. Curr Gastroenterol Rep 12:310-8
Kosinski, Cynthia; Stange, Daniel E; Xu, Chuanrui et al. (2010) Indian hedgehog regulates intestinal stem cell fate through epithelial-mesenchymal interactions during development. Gastroenterology 139:893-903
Mittal, Sahil; Mifflin, Randy; Powell, Don W (2009) Cancer stem cells: the other face of Janus. Am J Med Sci 338:107-12
Pinchuk, Irina V; Saada, Jamal I; Beswick, Ellen J et al. (2008) PD-1 ligand expression by human colonic myofibroblasts/fibroblasts regulates CD4+ T-cell activity. Gastroenterology 135:1228-1237, 1237.e1-2
Kosinski, Cynthia; Li, Vivian S W; Chan, Annie S Y et al. (2007) Gene expression patterns of human colon tops and basal crypts and BMP antagonists as intestinal stem cell niche factors. Proc Natl Acad Sci U S A 104:15418-23
Di Mari, J F; Saada, J I; Mifflin, R C et al. (2007) HETEs enhance IL-1-mediated COX-2 expression via augmentation of message stability in human colonic myofibroblasts. Am J Physiol Gastrointest Liver Physiol 293:G719-28
Pinchuk, Irina V; Beswick, Ellen J; Saada, Jamal I et al. (2007) Monocyte chemoattractant protein-1 production by intestinal myofibroblasts in response to staphylococcal enterotoxin a: relevance to staphylococcal enterotoxigenic disease. J Immunol 178:8097-106

Showing the most recent 10 out of 21 publications