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Genomes and Genes | Bile acid-induced colon cancer cell proliferationSummaryPrincipal Investigator: Jean Pierre Raufman Affiliation: University of Maryland Country: USA Abstract: The central hypothesis to be tested in this proposal is that bile acids induce colon cancer cell proliferation by interaction with M3 muscarinic receptors (M3R), thereby causing transactivation of epidermal growth factor receptors (EGFR). To elucidate post-receptor signaling that results in bile acid-induced colon cancer cell proliferation and to determine the requirement for, and mechanism of, transactivation of EGFR the following Specific Aims are proposed: 1. To elucidate further post-receptor signal transduction pathways which mediate cholinergic agonist-induced transactivation of EGFR and stimulate colon cancer cell proliferation. 1a. For use in the proposed studies, in addition to cells that naturally express M3R and EGFR, colon cancer cells will be transfected with cDNA clones for M3R and/or EGFR. 1b. The mechanism of cholinergic agonist-induced cell proliferation will be studied using immunoblotting to probe for activated proteins in the p44/42 MARK, p38 MARK and JNK pathways, and by examining the roles of phospholipase C and protein kinase C activation and Ca2+ mobilization.1c. The requirement for cholinergic agonist-induced transactivation of EGFR will be confirmed by examining EGFR phosphorylation and by using EGFR inhibitors, antisense oligonucleotides, and dominant negative mutants.2. To determine the requirement for co-expression of M3R and EGFR and delineate the molecular mechanisms whereby bile acids regulate colon cancer cell proliferation. 2a. Bile acid-induced post-receptor signaling and the requirement for co-expression of M3R and EGFR will be determined using radioligand binding assays, immunoblotting for activated p44/42 MARK, p38 MARK and JNK cascade proteins, and by using EGFR inhibitors, antisense oligonucleotides, and dominant negative mutants. 2b. Bile acid-induced activation and expression of transcription factors (p90RSK, p38 MARK and JNK) and genes (CREB, NF-kappaB, c-Fos and c-Jun) related to colon cancer proliferation will be elucidated. 3. To determine the molecular mechanism in human colon cancer cells of bile acid-induced transactivation of EGFR. 3a) Expression and release of EGFR ligands, including HB-EGF, will be determined using immunoblots, northern blots, and RT-PCR, and the dependence of bile acid-induced EGFR transactivation on release of EGFR ligands will be determined using EGFR antibodies, metalloproteinase inhibitors, and specific antibodies and inhibitors for EGFR. 3b) Colon cancer cell metalloproteases will be identified by immunoblotting and in situ hybridization and the role of these enzymes in mediating bile acid-induced HB-EGF release will be determined by using metalloprotease inhibitors and antisera, and by knocking down metalloprotease expression. 3c) The mechanism whereby bile acids activate metalloproteases will be determined by exploring the roles of PKC, Ca2+, and Src in bile acid-induced HB-EGF release. Funding Period: 2005-06-28 - 2010-05-31 more information: NIH RePORT Top Publications
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Akt-dependent NF-kappaB activation is required for bile acids to rescue colon cancer cells from stress-induced apoptosisJasleen Shant
Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
Exp Cell Res 315:432-50. 2009..These findings provide a mechanism whereby bile acids increase resistance of colon cancer to chemotherapy and radiation...
Bile acid-induced proliferation of a human colon cancer cell line is mediated by transactivation of epidermal growth factor receptorsKunrong Cheng
Division of Gastroenterology and Hepatology, VA Maryland Health Care System and Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, 22 S. Green Street, N3W62 Baltimore, MD 21201, USA
Biochem Pharmacol 70:1035-47. 2005..Collectively, these results suggest that in this colon cancer cell line, bile acid-induced colon cancer cell proliferation is M3R-dependent and is mediated by transactivation of EGFR...- Matrix metalloproteinase-7-catalyzed release of HB-EGF mediates deoxycholyltaurine-induced proliferation of a human colon cancer cell lineKunrong Cheng
Division of Gastroenterology and Hepatology, VA Maryland Health Care System and Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, 22 S Greene Street, N3W62, Baltimore, MD 21201, USA
Biochem Pharmacol 73:1001-12. 2007..These findings provide strong evidence that in H508 human colon cancer cells, DCT-induced transactivation of EGFR is mediated by MMP-7-catalyzed release of the EGFR ligand HB-EGF... - Human cecal bile acids: concentration and spectrumJames P Hamilton
Division of Gastroenterology and Hepatology, Department of Medicine, Veterans Affairs Maryland Health Care System and University of Maryland School of Medicine, 22 S Greene Street, Baltimore, MD 21201, USA
Am J Physiol Gastrointest Liver Physiol 293:G256-63. 2007..In the human cecum, deconjugation and dehydroxylation of bile acids are nearly complete, resulting in most bile acids being in unconjugated form at submicellar and subsecretory concentrations... - Deoxycholyltaurine rescues human colon cancer cells from apoptosis by activating EGFR-dependent PI3K/Akt signalingJean Pierre Raufman
Division of Gastroenterology and Hepatology, VA Maryland Health Care System and Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
J Cell Physiol 215:538-49. 2008..Collectively, these results indicate that DCT-induced activation of post-EGFR PI3K/Akt signaling stimulates both colon cancer cell survival and proliferation... - Genetic ablation of M3 muscarinic receptors attenuates murine colon epithelial cell proliferation and neoplasiaJean Pierre Raufman
Division of Gastroenterology and Hepatology, VA Maryland Health Care System and Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, USA
Cancer Res 68:3573-8. 2008..001). Compared with WT, azoxymethane-treated M(3)R-deficient mice have attenuated epithelial cell proliferation, tumor number, and size. M(3)R and post-M(3)R signaling are novel therapeutic targets for colon cancer... - Acetylcholine release by human colon cancer cells mediates autocrine stimulation of cell proliferationKunrong Cheng
Division of Gastroenterology and Hepatology, Veterans Affairs Maryland Healthcare System, University of Maryland School of Medicine, Department of Pathology, 22 S Greene St, N3W62, Baltimore, MD 21201, USA
Am J Physiol Gastrointest Liver Physiol 295:G591-7. 2008..005). We conclude that ACh is an autocrine growth factor in colon cancer. Mechanisms that regulate colon epithelial cell production and release of ACh warrant further investigation... - Muscarinic receptors and ligands in cancerNirish Shah
Division of Gastroenterology and Hepatology, Univ of Maryland School of Medicine, 22 South Greene St, N3W62, Baltimore, MD 21201, USA
Am J Physiol Cell Physiol 296:C221-32. 2009..Dissecting cellular mechanisms necessary for muscarinic receptor activation as well as those needed for acetylcholine production and release will identify multiple novel targets for cancer therapy... - Acetylcholine-induced activation of M3 muscarinic receptors stimulates robust matrix metalloproteinase gene expression in human colon cancer cellsGuofeng Xie
Division of Gastroenterology and Hepatology, Veterans Administration Maryland Health Care System and Program in Oncology, Greenbaum Cancer Center, University of Maryland School of Medicine, 22 S Greene St, N3W62, Baltimore, MD 21201, USA
Am J Physiol Gastrointest Liver Physiol 296:G755-63. 2009..ACh-induced activation of EGFR and downstream ERK signaling also regulates transcriptional activation of MMP7, thereby identifying a novel feed-forward mechanism for neoplastic cell proliferation...