Preventive Effects of Heat-Killed Enterococcus faecalis Strain EC-12 on Mouse Intestinal Tumor Development

• Published in: International journal of molecular sciences Vol. 18; no. 4; p. 826
• Main Authors: Miyamoto, Shingo, Komiya, Masami, Fujii, Gen, Hamoya, Takahiro, Nakanishi, Ruri, Fujimoto, Kyoko, Tamura, Shuya, Kurokawa, Yurie, Takahashi, Maiko, Ijichi, Tetsuo, Mutoh, Michihiro
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.04.2017; MDPI
• Subjects: Animals; Bacteria; beta Catenin - metabolism; Carcinogenesis; Cell Line, Tumor; Chemoprevention; Colorectal cancer; Colorectal Neoplasms - prevention & control; Cyclin D1 - genetics; Cyclin D1 - metabolism; Diet; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; Enterococcus faecalis; Enterococcus faecalis - genetics; Enterococcus faecalis - physiology; Face - microbiology; Female; Females; Functional Food - microbiology; HCT116 Cells; Hot Temperature; Humans; Intestinal Polyps - pathology; Male; Mice; Mice, Inbred C57BL; Promoter Regions, Genetic; Proto-Oncogene Proteins c-myc - genetics; Proto-Oncogene Proteins c-myc - metabolism; RNA, Messenger; Signal Transduction; TCF Transcription Factors - genetics; TCF Transcription Factors - metabolism; Transcriptional Activation; functional foods; colorectal cancer chemoprevention; heat-killed EC-12; intestinal polyps; Min mice
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms18040826

Establishing effective methods for preventing colorectal cancer by so-called “functional foods” is important because the global burden of colorectal cancer is increasing. Enterococcus faecalis strain EC-12 (EC-12), which belongs to the family of lactic acid bacteria, has been shown to exert pleiotropic effects, such as anti-allergy and anti-infectious effects, on mammalian cells. In the present study, we aimed to evaluate the preventive effects of heat-killed EC-12 on intestinal carcinogenesis. We fed 5-week-old male and female Apc mutant Min mice diets containing 50 or 100 ppm heat-killed EC-12 for 8 weeks. In the 50 ppm treated group, there was 4.3% decrease in the number of polyps in males vs. 30.9% in females, and significant reduction was only achieved in the proximal small intestine of female mice. A similar reduction was observed in the 100 ppm treated group. Moreover, heat-killed EC-12 tended to reduce the levels of c-Myc and cyclin D1 mRNA expression in intestinal polyps. Next, we confirmed that heat-killed EC-12 suppressed the transcriptional activity of the T-cell factor/lymphoid enhancer factor, a transcriptional factor involved in cyclin D1 mRNA expression in intestinal polyps. Our results suggest that heat-killed EC-12 very weakly suppresses intestinal polyp development in Min mice, in part by attenuating β-catenin signaling, and this implies that heat-killed EC-12 could be used as a “functional food”.