Bacteria enhance tumorigenesis through activating intestinal stem | 21123
Journal of Cell Science & Therapy

Journal of Cell Science & Therapy
Open Access

ISSN: 2157-7013

+44 1300 500008

Bacteria enhance tumorigenesis through activating intestinal stem cells related signaling pathways

International Conference & Exhibition on Cell Science & Stem Cell Research

29 Nov - 1 Dec 2011 Philadelphia Airport Marriott, USA

Jun Sun

Scientific Tracks Abstracts: J Cell Sci Ther

Abstract :

Th e number of microbial cells is about 10 times larger than the number of eukaryotic cells in the human body. Enteric bacteria play an important role in the pathogenesis of cancer. Due to the complexity of the gut fl ora, identifi cation of the specifi c microbial agents contributing to colon cancer remains challenging. How bacterial products directly contribute to cancer is still unknown. Bacteria can modulate the host by secreting bacterial eff ector proteins to the host cells. AvrA is a pathogenic protein of enteric bacteria that infl uences eukaryotic cell pathways utilizing ubiquitin and acetylation. We hypothesize that the bacterial eff ector AvrA activates the STAT/beta-catenin pathway to promote colonic tumorigenesis. We investigated a chronic bacterial infected cancer model with Salmonella colonization in the mouse intestine. Mice were colonized with AvrA- suffi cient or defi cient bacterial strains, then stimulated with a carcinogen azoxymethane and dextran sodium sulfate (induced colitis). We found that mice infected with AvrA-expressed bacteria had signifi cantly high incidence of tumor in colon. AvrA expression decreased the phosphorylated-beta-catenin and inhibits the ubiquitination of beta-catenin in mouse colonic epithelial cells in vivo . Additionally, AvrA expression enhanced the acetylated beta-catenin, which regulates the beta-catenin transcription activity. Moreover, infected colon had higher STAT 1 and 3 expressions. Infl ammatory cytokines such as IL-6 and INF-gamma in serum were increased. Overall, AvrA activation of the STAT/beta-catenin pathway promoted colonic tumorigenesis. Th e current study provides important insights into intestinal infection and cancer stem cells. Our fi ndings can also be applied to the risk assessment and prevention of cancer

Biography :

Dr. Jun Sun is currently an Assistant Professor at the University of Rochester. Her key achievements include identi fi cation and characterization of bacterial effector protein AvrA that activates the Wnt/beta-catenin pathway and affects intestinal epithelial stem cells in in fl ammation. Her long-range goal is to elucidate how a speci fi c bacterial effector provides a mechanistic link between in fl ammation of the intestine and the development of colon cancer. Dr. Sun is the author of 58 peer-reviewed papers, numerous chapters and invited reviews. She is an inventor of two patents. Her current researches are supported by the NIH, NY STEM, and the American Cancer Societ