Culture‐independent analysis of the gut microbiota in colorectal cancer and polyposis

Abstract

A role for the intestinal microbiota is routinely cited as a potential aetiological factor in colorectal cancer initiation and progression. As the majority of bacteria in the gut are refractory to culture we investigated this ecosystem in subjects with colorectal cancer and with adenomatous polyposis who are at high risk of developing colorectal cancer, using culture-independent methods. Twenty colorectal cancer and 20 polypectomized volunteers were chosen for this analysis. An exploration of the diversity and temporal stability of the dominant bacteria and several bacterial subgroups was undertaken using 16S rRNA gene denaturing gradient gel electrophoresis and ribosomal intergenic spacer analysis (RISA). Metabonomic analysis of the distal gut microbiota's environment was also undertaken. A significantly reduced temporal stability and increased diversity for the microbiota of subjects with colorectal cancer and polyposis was evident. A significantly increased diversity of the Clostridium leptum and C. coccoides subgroups was also noted for both disease groups. A clear division in the metabonome was observed for the colorectal cancer and polypectomized subjects compared with control volunteers. The intestinal microbiota and their metabolites are significantly altered in both colorectal cancer and polypectomized subjects compared with controls.

Probiotics modulated gut microbiota suppresses hepatocellular carcinoma growth in mice

“…As shown in Fig. 3B, Upper, the alpha diversity decreased drastically (50% on average) in all groups after 38 d. This loss of community diversity can be explained by the tumor-induced dysbiosis in the gut bacteria community, consistent with previous findings that some diseases could lead to an imbalanced gut microbiota and decrease the ecological diversity in the gut (21,22). When comparing the alpha diversity between the 38-d samples, we observed no significant difference between the control and ProTreat groups; however, cisplatin and ProPre groups showed significantly higher alpha diversity than both the control and ProTreat (Bonferroni adjusted P value < 0.05, Wilcoxon rank-sum test using 100 bootstrap samples).…”

Fusobacterium nucleatum associates with stages of colorectal neoplasia development, colorectal cancer and disease outcome

“…These micro-organisms are thought to create a microenvironment more favourable to CRC development [16]. It now seems that not only can the bacterial composition of the gut assist initiation and progression of colorectal tumours, but also that tumours can affect the representation of bacteria in their vicinity [10,12,17].…”

Increased rectal microbial richness is associated with the presence of colorectal adenomas in humans

“…The role of host-associated microbiota (Hope et al, 2005) has also been frequently proposed as a critical factor in CRC development (Huycke and Gaskins, 2004;Scanlan et al, 2008). Recent technological breakthroughs now allow for the study of the human-associated microbiome at a level of detail that was unimaginable only a few years ago (Margulies et al, 2005;Petrosino et al, 2009).…”