Approaches for prevention of colon cancer: Role of probiotics

A4 Lactic Acid Bacteria (LAB) are well known probiotics inhabiting our Gastrointestinal tract, reported to inhibit pathogenic organisms, to stimulate the intestinal immune system and also to produce nutrients such as short-chain fatty acids, vitamins, amino acids, polyamines, growth factors and antioxidants 1 . Recent studies have implicated probiotic bacteria in the prevention of cancers of the colon, modulation of immune function, control of blood cholesterol levels and suppression of allergies 2 . There is evidence that probiotics can interfere at various stages of cancer process such as prevention of DNA damage in the colonic epithelial cells by live bacteria, suppression of pre-neoplastic changes in the colon and suppression of colon tumors in animals 3,4,5 . In the present investigation LAB were isolated from normal and polypoidal human colonic mucosa and characterized for their probiotic potential such as antibacterial activity against enteric pathogens, bile tolerance and acid tolerance. Selected probiotic LAB were studied for their cytotoxicity and adherence capacity to colon cancer cell lines (HCT15) and Intestinal epithelial cell lines (HT29, Caco2). A comparative study of the most efficient anticancerous LAB strains were carried out based on cytotoxicity and bacterial adherence to cell lines. Results show that the anticancerous effect is strain specific. Studies are ongoing to understand the mechanisms of anticancerous activity in individual strains for furthur strain improvement and therapeutic applications. The results provide insights on the optimum probiotic culture and conditions for improved anticancerous potential. Acknowledgements: Authors wish to acknowledge the financial support from the Science and Engineering Research Council (SERC) of the Department of Science and Technology, Govt. of India.References Amy C. Brown, Ph.D., R.D. Ana Valiere, M.S. Probiotics and Medical Nutrition Therapy Nutr Clin Care . 2004 ; 7(2): 56-68. Daniel C, Roisin H, Colette S, Ian R. The potential mechanisms involved in the anti-carcinogenic action of probiotics Mutat Res 2005; 591: 276-289 Marteau P, Pochart P, Flourie B . Effect of chronic ingestion of a fermented dairy product containing Lactobacillus acidophilus and Bifidobacterium bifidum on metabolic activities of the colonic flora in humans. Am J Clin Nutr 1990;52:685-688. Pedrosa MC, Golner BB, Goldin BR, Barakat S, Dallal GE, Russell RM. Survival of yogurt-containingorganisms and Lactobacillus gasseri (ADH) and their effect on bacterial enzyme activity in the gastrointestinal tract of healthy and hypochlorhydric elderly subjects. Am J Clin Nutr 1995;61:353-359. Orrhage K, Sillerstrom E, Gustafsson JA, Nord CE, Rafter J. Binding of mutagenic heterocyclic amines by intestinal and lactic acid bacteria. Mutat Res 1994;311:239-248.