A pilot study on clinicopathological features and intestinal microflora changes in colorectal cancer patients born over a nine-year period encompassing three years before and after the Great Chinese famine

Microbiota composition and its impact on DNA methylation in colorectal cancer

Colorectal cancer is a complex disease resulting from the interaction of genetics, epigenetics, and environmental factors. DNA methylation is frequently found in tumor suppressor genes to promote cancer development. Several factors are associated with changes in the DNA methylation pattern, and recently, the gastrointestinal microbiota could be associated with this epigenetic change. The predominant phyla in gut microbiota are Firmicutes and Bacteroidetes; however, an enrichment of Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus bovis, among others, has been reported in colorectal cancer, although the composition could be influenced by several factors, including diet, age, sex, and cancer stage. Fusobacterium nucleatum, a gram-negative anaerobic bacillus, is mainly associated with colorectal cancer patients positive for the CpG island methylator phenotype, although hypermethylation in genes such as MLH1, CDKN2A, MTSS1, RBM38, PKD1, PTPRT, and EYA4 has also been described. Moreover, Hungatella hathewayi, a gram-positive, rod-shaped bacterium, is related to hypermethylation in SOX11, THBD, SFRP2, GATA5, ESR1, EYA4, CDX2, and APC genes. The underlying epigenetic mechanism is unclear, although it could be implicated in the regulation of DNA methyltransferases, enzymes that catalyze the transfer of a methyl group on cytosine of CpG sites. Since DNA methylation is a reversible event, changes in gut microbiota could modulate the gene expression through DNA methylation and improve the colorectal cancer prognosis.

Translation of nutrigenomic research for personalised and precision nutrition for cancer prevention and for cancer survivors

Personalised and precision nutrition uses information on individual characteristics and responses to nutrients, foods and dietary patterns to develop targeted nutritional advice that is more effective in improving the diet and health of each individual. Moving away from the conventional 'one size fits all', such targeted intervention approaches may pave the way to better population health, including lower burden of non-communicable diseases. To date, most personalised and precision nutrition approaches have been focussed on tackling obesity and cardiometabolic diseases with limited efforts directed to cancer prevention and for cancer survivors. Advances in understanding the biological basis of cancer and of the role played by diet in cancer prevention and in survival after cancer diagnosis, mean that it is timely to test and to apply such personalised and precision nutrition approaches in the cancer area. This endeavour can take advantage of the enhanced understanding of interactions between dietary factors, individual genotype and the gut microbiome that impact on risk of, and survival after, cancer diagnosis. Translation of these basic research into public health action should include real-time acquisition of nutrigenomic and related data and use of AI-based data integration methods in systems approaches that can be scaled up using mobile devices.

Energy balance‐related factors in childhood and adolescence and risk of colorectal cancer expressing different levels of proteins involved in the Warburg‐effect

Early‐life (childhood to adolescence) energy balance‐related factors (height, energy restriction, BMI) have been associated with adult colorectal cancer (CRC) risk. Warburg‐effect activation via PI3K/Akt‐signaling might explain this link. We investigated whether early‐life energy balance‐related factors were associated with risk of Warburg‐subtypes in CRC. We used immunohistochemistry for six proteins involved in the Warburg‐effect (LDHA, GLUT1, MCT4, PKM2, P53, and PTEN) on tissue microarrays of 2399 incident CRC cases from the prospective Netherlands Cohort Study (NLCS). Expression levels of all proteins were combined into a pathway‐based sum score and categorized into three Warburg‐subtypes (Warburg‐low/‐moderate/‐high). Multivariable Cox‐regression analyses were used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter; Second World War [WWII]; Economic Depression) and adolescent BMI with Warburg‐subtypes in CRC. Height was positively associated with colon cancer in men, regardless of Warburg‐subtypes, and with Warburg‐low colon and Warburg‐moderate rectal cancer in women. Energy restriction during the Dutch Hunger Winter was inversely associated with colon cancer in men, regardless of Warburg‐subtypes. In women, energy restriction during the Hunger Winter and WWII was inversely associated with Warburg‐low colon cancer, whereas energy restriction during the Economic Depression was positively associated with Warburg‐high colon cancer. Adolescent BMI was positively associated with Warburg‐high colon cancer in men, and Warburg‐moderate rectal cancer in women. In conclusion, the Warburg‐effect seems to be involved in associations of adolescent BMI with colon cancer in men, and of energy restriction during the Economic Depression with colon cancer in women. Further research is needed to validate these results.

In utero and childhood exposure to the Great Chinese Famine and risk of cancer in adulthood: the Kailuan Study

BACKGROUND

The risk of cancer in adulthood can be influenced by exposure to environmental factors (e.g., food shortage and stress) in early life.

OBJECTIVES

This study compared the risk of cancer morbidity and mortality between Chinese adults who were or were not exposed to the Great Chinese Famine (1959-1961) in utero or during early childhood.

METHODS

The Kailuan Study participants (n = 101,095) were classified into 5 famine exposure groups by birth year collected at study baseline (2006-2007): after 1961 (unexposed), 1959-1961 (in utero exposed), 1956-1958 (infancy and early childhood exposed, aged 0.1-2.9 y), 1953-1955 (childhood exposed, aged 3.0-5.9 y), and before 1953 (exposed, aged 6+ y). They were further classified by the severity of famine exposure. Cancer and cancer mortality cases from 2006 to 2016 were confirmed by reviewing medical records. Cox proportional hazard models were computed, adjusting for sex, socioeconomic status, and other time-varying cancer-related covariates.

RESULTS

During a median follow-up of 10.0 y, we identified 3560 incident cancer cases and 1749 cancer deaths. Famine exposure at all ages was positively associated with the risk of cancer morbidity and mortality (P < 0.001 for all, compared with unexposed). Severe exposure to famine in early childhood, but not other ages, had a higher risk of composite cancer events [adjusted HR = 2.04 (95% CI: 1.47, 2.84) for 0.1-2.9 y; and 1.61 (95% CI: 1.15, 2.25) for 3.0-5.9 y], relative to the less severely exposed groups of the same age range. When cancer morbidity and mortality were studied separately, similar patterns were observed.

CONCLUSIONS

In utero and early childhood exposures to famine, especially severe famine, were associated with a higher risk of cancer morbidity and mortality in adulthood. Awareness should be raised regarding the long-term effect of early life nutritional status.Trial registration number: ChiCTR-TNRC-11001489 (http://www.chictr.org.cn/showprojen.aspx?proj=8050).

Emerging Evidence on the Effects of Dietary Factors on the Gut Microbiome in Colorectal Cancer

Dietary factors have important role in modulating the gut microbiome, which in-turn regulates the molecular events in colonic mucosa. The composition and resulting metabolism of the gut microbiome are decisive factors in colorectal cancer (CRC) tumorigenesis. Altered gut microbiome is associated with impaired immune response, and the release of carcinogenic or genotoxic substances which are the major microbiome-induced mechanisms implicated in CRC pathogenesis. Diets low in dietary fibers and phytomolecules as well as high in red meat are important dietary changes which predispose to CRC. Dietary fibers which reach the colon in an undigested form are further metabolized by the gut microbiome into enterocyte friendly metabolites such as short chain fatty acid (SCFA) which provide anti-inflammatory and anti-proliferative effects. Healthy microbiome supported by dietary fibers and phytomolecules could decrease cell proliferation by regulating the epigenetic events which activate proto-oncogenes and oncogenic pathways. Emerging evidence show that predominance of microbes such as Fusobacterium nucleatum can predispose the colonic mucosa to malignant transformation. Dietary and lifestyle modifications have been demonstrated to restrict the growth of potentially harmful opportunistic organisms. Synbiotics can protect the intestinal mucosa by improving immune response and decreasing the production of toxic metabolites, oxidative stress and cell proliferation. In this narrative review, we aim to update the emerging evidence on how diet could modulate the gut microbial composition and revive colonic epithelium. This review highlights the importance of healthy plant-based diet and related supplements in CRC prevention by improving the gut microbiome.

An overview of the level of dietary support in the gut microbiota at different stages of life: A systematic review

BACKGROUND & AIMS

The gut microbiome is an essential factor for the health of the host. Several factors may alter the gut's microbiota composition, including genetic factors, lifestyle, aging, and dietary intervention. This process can be an essential element in the prevention and treatment of diseases associated with microbiome dysfunction through appropriate dietary interventions. Based on this context, a systematic review was carried out in order to assess the effect of dietary intervention on the profile of the gut microbiota throughout different stages of life.

METHODS

The systematic review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA), with the eligibility criteria following the principle of PICOS. The literature search was carried out in 2019 throughout PubMed/MEDLINE, Scopus, and Science Direct. Thus, 1237 studies were selected, and 40 articles were included by criteria.

RESULTS

According to the level of evidence of Centre for Evidence-Based Medicine (OCEBM), 21 studies reached the level of evidence B1, 15 articles were classified with B2, and four articles with B3. No dietary intervention was applied at all stages of life, nor with similar proportions of intervention. No dietary intervention was applied at all stages of life, nor with similar proportions of intervention. On the other hand, dietary interventions alter the intestinal microbiota in different pathological realities.

CONCLUSIONS

Different dietary interventions change the microbiome composition at all stages of life in healthy and pathological individuals. However, more clinical studies are needed to identify the specifics of each stage in response to interventions.

Association of Helicobacter bilis Infection with the Development of Colorectal Cancer

The role of Helicobacter_bilis (H.bilis) in the development of inflammatory bowel disease (IBD) and colitis-associated carcinogenesis (CAC) has seldom been investigated. We examined the abundance of H.bilis in 58 colorectal cancers (CRCs), 20 IBDs, 40 cases of normal colorectal mucosa (NCs), and 20 adenomas (ADs) by 16S rRNA fluorescence in situ hybridization (FISH). Number of CD4⁺CD45RB⁺T cell and expression of IFN-γ and TNF-α in these tissues was determined by immunofluorescence. The abundance of H.bilis was significantly higher in CRCs than that in IBDs (P = 0.006), ADs (P < 0.001) and NCs (P < 0.0001). The abundance of H.bilis in IBDs was significantly higher than that in ADs (P = 0.013). Moreover, the average number of CD4⁺CD45RB⁺T cell was significantly higher in CRCs than that in IBDs (P = 0.017) and NCs (P = 0.009). In addition, there was a positive correlation between the H.bilis abundance and density of CD4⁺CD45RB⁺T cells in 30 colorectal tissues (P < 0.0001). The frequency of co-staining for CD4⁺CD45RB⁺T cells and IFN-γ was significantly higher in H.bilis positive group than that in H.bilis negative group (P = 0.002). H.bilis may play a role in the initiation of IBD and CAC, possibly through promoting the transformation of T cells into CD4⁺CD45RB⁺T cells and increasing the expression of proinflammatory cytokines IFN-γ.