Promotion of intestinal carcinogenesis by Streptococcus bovis

• Published in: Carcinogenesis (New York) Vol. 21; no. 4; pp. 753 - 756
• Main Authors: Ellmerich, Stéphan, Schöller, Marie, Duranton, Benoît, Gossé, Francine, Galluser, Michel, Klein, Jean-Paul, Raul, Francis
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-04-2000; Oxford Publishing Limited (England)
• Subjects: aberrant crypt foci; ACF; Adenoma - etiology; Animals; AOM; Azoxymethane; Bacteriology; BHI; Biogenic Polyamines - analysis; Biological and medical sciences; brain–heart infusion broth; Carcinogenesis, carcinogens and anticarcinogens; Cell Division; Cocarcinogenesis; Colon - metabolism; Foods and miscellaneous; Fundamental and applied biological sciences. Psychology; Interleukin-8 - biosynthesis; Intestinal Neoplasms - etiology; Male; Medical sciences; Microbiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; PBS; PCNA; phosphate-buffered saline; Precancerous Conditions - etiology; proliferating cell nuclear antigen; Rats; Rats, Wistar; Streptococcus bovis; Streptococcus bovis - pathogenicity; Tumors; wall-extracted antigens; WEA; Cell proliferation; Intraperitoneal administration; Premalignant lesion; Rat; Toxicity; Rodentia; Oral administration; Malignant tumor; Streptococcus bovis; Colonic disease; Antigen; Streptococcaceae; Carcinogen; Vertebrata; Azoxy compound; Mammalia; Animal; Digestive diseases; Bacteria; Intestinal disease; Micrococcales; Colon; Tumor promotion; PCNA antigen
• ISSN: 0143-3334; 1460-2180
• DOI: 10.1093/carcin/21.4.753

The involvement of Streptococcus bovis, an member of the human gut flora, in colorectal neoplastic diseases is an object of controversy. The aim of this study was to determine the effects of S.bovis and of antigens extracted from the bacterial cell wall on early preneoplastic changes in the intestinal tract. Adult rats received i.p. injections of azoxymethane (15 mg/kg body weight) once per week for 2 weeks. Fifteen days (week 4) after the last injection of the carcinogen, the rats received, by gavage twice per week during 5 weeks, either S.bovis (1010 bacteria) or wall-extracted antigens (100 μg). One week after the last gavage (week 10), we found that administration of either S.bovis or of antigens from this bacterium promoted the progression of preneoplastic lesions through the increased formation of hyperproliferative aberrant colonic crypts, enhanced the expression of proliferation markers and increased the production of IL-8 in the colonic mucosa. Our study suggests that S.bovis acts as a promoter of early preneoplastic lesions in the colon of rats. The fact that bacterial wall proteins are more potent inducers of neoplastic transformation than the intact bacteria may have important implications in colon cancer prevention.