Review
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World J Gastroenterol. Jun 28, 2014; 20(24): 7878-7886
Published online Jun 28, 2014. doi: 10.3748/wjg.v20.i24.7878
Emerging roles of lactic acid bacteria in protection against colorectal cancer
Li Zhong, Xufei Zhang, Mihai Covasa
Li Zhong, Xufei Zhang, Mihai Covasa, Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, United States
Li Zhong, Xufei Zhang, Department of Cell Biology, College of Life Sciences, Hebei University, Baoding 071002, Hebei Province, China
Mihai Covasa, Institut National de la Recherche Agronomique (INRA), UMR1319 Micalis, Domaine de Vilvert, 78352 Jouy-en-Josas, France
Mihai Covasa, Department of Human and Health Development, University of Suceava, Suceava 720229, Romania
Author contributions: All authors conceptualized and wrote the manuscript.
Supported by Grant No. NSFC-81272444 to Zhong L; and No. PN-II-ID-PCE-2012-4-0608 Nr. 48/02.09.2013 to Covasa M
Correspondence to: Li Zhong, Associate Professor, Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309E Second Street, Pomona, CA 91766, United States. lzhong@westernu.edu
Telephone: +1-909-4698220 Fax: +1-909-4695698
Received: November 27, 2013
Revised: March 1, 2014
Accepted: March 12, 2014
Published online: June 28, 2014
Processing time: 212 Days and 7 Hours
Abstract

Colorectal cancer (CRC) is the third leading cause of cancer deaths worldwide and the fourth most common cancer diagnosed among men and women in the United States. Considering the risk factors of CRC, dietary therapy has become one of the most effective approaches in reducing CRC morbidity and mortality. The use of probiotics is increasing in popularity for both the prevention and treatment of a variety of diseases. As the most common types of microbes used as probiotics, lactic acid bacteria (LAB) are comprised of an ecologically diverse group of microorganisms united by formation of lactic acid as the primary metabolite of sugar metabolism. LAB have been successfully used in managing diarrhea, food allergies, and inflammatory bowel disease. LAB also demonstrated a host of properties in preventing colorectal cancer development by inhibiting initiation or progression through multiple pathways. In this review, we discuss recent insights into cellular and molecular mechanisms of LAB in CRC prevention including apoptosis, antioxidant DNA damages, immune responses, and epigenetics. The emerging experimental findings from clinical trials as well as the proposed mechanisms of gut microbiota in carcinogenesis will also be briefly discussed.

Keywords: Gut bacteria; Gastrointestinal; Carcinogenesis; Probiotics; Microbiota

Core tip: The gastrointestinal tract inhabits trillions of bacteria that interact with the host at multiple levels to maintain its normal functions. Disruptions in this complex cross-talk ecosystem result in physiological changes associated with colorectal tumorigenesis, including cell proliferation, immune responses and apoptosis. This review summarizes the role of lactic acid bacteria as anti-tumorigenic probiotics and suggests the possibility of altering gut microbiota to prevent or halt development of colorectal cancer.