The role of Fusobacterium nucleatum in colorectal cancer: from carcinogenesis to clinical management

Toll-Like Receptor 2 at the Crossroad between Cancer Cells, the Immune System, and the Microbiota

Toll-like receptor 2 (TLR2) expressed on myeloid cells mediates the recognition of harmful molecules belonging to invading pathogens or host damaged tissues, leading to inflammation. For this ability to activate immune responses, TLR2 has been considered a player in anti-cancer immunity. Therefore, TLR2 agonists have been used as adjuvants for anti-cancer immunotherapies. However, TLR2 is also expressed on neoplastic cells from different malignancies and promotes their proliferation through activation of the myeloid differentiation primary response protein 88 (MyD88)/nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) pathway. Furthermore, its activation on regulatory immune cells may contribute to the generation of an immunosuppressive microenvironment and of the pre-metastatic niche, promoting cancer progression. Thus, TLR2 represents a double-edge sword, whose role in cancer needs to be carefully understood for the setup of effective therapies. In this review, we discuss the divergent effects induced by TLR2 activation in different immune cell populations, cancer cells, and cancer stem cells. Moreover, we analyze the stimuli that lead to its activation in the tumor microenvironment, addressing the role of danger, pathogen, and microbiota-associated molecular patterns and their modulation during cancer treatments. This information will contribute to the scientific debate on the use of TLR2 agonists or antagonists in cancer treatment and pave the way for new therapeutic avenues.

Fate of Hematopoiesis During Aging. What Do We Really Know, and What are its Implications?

There is an ongoing shift in demographics such that older persons will outnumber young persons in the coming years, and with it age-associated tissue attrition and increased diseases and disorders. There has been increased information on the association of the aging process with dysregulation of hematopoietic stem (HSC) and progenitor (HPC) cells, and hematopoiesis. This review provides an extensive up-to date summary on the literature of aged hematopoiesis and HSCs placed in context of potential artifacts of the collection and processing procedure, that may not be totally representative of the status of HSCs in their in vivo bone marrow microenvironment, and what the implications of this are for understanding aged hematopoiesis. This review covers a number of interactive areas, many of which have not been adequately explored. There are still many unknowns and mechanistic insights to be elucidated to better understand effects of aging on the hematopoietic system, efforts that will take multidisciplinary approaches, and that could lead to means to ameliorate at least some of the dysregulation of HSCs and HPCs associated with the aging process. Graphical Abstract.

Could Periodontal Disease through Periopathogen Fusobacterium Nucleatum be an Aggravating Factor for Gastric Cancer?

Periodontal disease affects the supporting tissues of the teeth, being a chronic inflammatory disease caused by specific microorganisms from subgingival biofilm. Fusobacterium nucleatum is a Gram-negative anaerobic bacterium that acts as a periodontal pathogen, being an important factor in linking Gram-positive and Gram-negative bacteria in the periodontal biofilm, but its involvement in systemic diseases has also been found. Several studies regarding the implication of Fusobacterium nucleatum in gastro-enterological cancers have been conducted. The present review aims to update and systematize the latest information about Fusobacterium nucleatum in order to evaluate the possibility of an association between periodontal disease and the evolution of gastroenterological cancers through the action of Fusobacterium nucleatum, highlighting gastric cancer. This would motivate future research on the negative influence of periodontal pathology on the evolution of gastric cancer in patients suffering from both pathologies.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

Use of the synbiotic VSL#3 and yacon-based concentrate attenuates intestinal damage and reduces the abundance of Candidatus Saccharimonas in a colitis-associated carcinogenesis model

Individuals with inflammatory bowel disease are at high risk of developing colitis-associated cancer; thus, strategies to inhibit disease progression should be investigated. The study aimed to explore the role of the synbiotic (probiotic VSL#3® and yacon-based concentrate) in a colitis-associated carcinogenesis model. IL-10^-/- mice were induced to carcinogenesis with 1,2-dimethylhydrazine and divided into two experimental groups: control and synbiotic. Manifestations of colitis, colon histology, expression of antioxidant enzymes, production of organic acids and intestinal microbiota were evaluated. The use of the synbiotic showed benefits, such as the preservation of intestinal architecture, increased expression of antioxidant enzymes and the concentration of organic acids, especially butyrate. It was also observed different microbial community profiles between the groups during the study. Together, these factors contributed to mitigate the manifestations of colitis and improve intestinal integrity, suggesting the potential benefit of the synbiotic in intestinal diseases.

Fusobacterium nucleatum Accelerates the Progression of Colitis-Associated Colorectal Cancer by Promoting EMT

Simple Summary

Colitis-associated cancer (CAC) are associated with the development and progression of colorectal cancer (CRC). And Fusobacterium nucleatum (F. nucleatum), a major pathogen involved in chronic periodontitis, may play an important role in CRC progression. Though the importance of F. nucleatum in CRC has attracted attention, its exact role and related mechanism in CAC progression remain unclear. We investigated the effects of F. nucleatum in both in vitro and in vivo colitis models induced with dextran sodium sulfate (DSS), a well-known colitis-inducing chemical, on the aggressiveness of CAC and its related mechanism. This study showed that F. nucleatum accelerates the progression of CAC cancer by promoting epithelial–mesenchymal transition (EMT). This study provides a novel mechanism involved F. nucleatum in the development of colitis-associated CRC.

Abstract

Recently, it has been reported that Fusobacterium nucleatum, a major pathogen involved in chronic periodontitis, may play an important role in colorectal cancer (CRC) progression. In addition, inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease represent major predisposing conditions for the development of CRC, and this subtype of cancer is called colitis-associated cancer (CAC). Although the importance of F. nucleatum in CRC has attracted attention, its exact role and related mechanism in CAC progression remain unclear. In this study, we investigated the effects of F. nucleatum in experimental colitis induced with dextran sodium sulfate (DSS), which is a well-known colitis-inducing chemical, on the aggressiveness of CAC and its related mechanism in both in vitro and in vivo models. F. nucleatum synergistically increased the aggressiveness and epithelial–mesenchymal transition (EMT) characteristics of CRC cells that were treated with DSS compared to those in non-treated CRC cells. The role of F. nucleatum in CAC progression was further confirmed in mouse models, as F. nucleatum was found to significantly increase the malignancy of azoxymethane (AOM)/DSS-induced colon cancer. This promoting effect of F. nucleatum was based on activation of the EGFR signaling pathways, including protein kinase B (AKT) and extracellular signal-regulated kinase (ERK), and epidermal growth factor receptor (EGFR) inhibition significantly reduced the F. nucleatum-induced EMT alteration. In conclusion, F. nucleatum accelerates the progression of CAC by promoting EMT through the EGFR signaling pathway.

Gut Microbiota-Mediated Inflammation and Gut Permeability in Patients with Obesity and Colorectal Cancer

Obesity is considered an important factor that increases the risk of colorectal cancer (CRC). So far, the association of gut microbiota with both obesity and cancer has been described independently. Nevertheless, a specific obesity-related microbial profile linked to CRC development has not been identified. The aim of this study was to determine the gut microbiota composition in fecal samples from CRC patients with (OB-CRC) and without obesity (L-CRC) compared to the microbiota profile present in non-obese healthy controls (L-HC), in order to unravel the possible relationship between gut microbiota and microbial-derived metabolite trimethylamine N-oxide (TMAO), the inflammatory status, and the intestinal permeability in the context of obesity-associated CRC. The presence of obesity does not induce significant changes in the diversity and richness of intestinal bacteria of CRC patients. Nevertheless, OB-CRC patients display a specific gut microbiota profile characterized by a reduction in butyrate-producing bacteria and an overabundance of opportunistic pathogens, which in turn could be responsible, at least in part, for the higher levels of proinflammatory cytokine IL-1β, the deleterious bacterial metabolite TMAO, and gut permeability found in these patients. These results suggest a possible role of obesity-related gut microbiota in the development of CRC, which could give new clues for the design of new diagnostic tools for CRC prevention.

Microbiota and Cancer: The Emerging Beneficial Role of Bifidobacteria in Cancer Immunotherapy

Many intestinal bacteria are believed to be involved in various inflammatory and immune processes that influence tumor etiology because of their metabolic properties and their ability to alter the microbiota homeostasis. Although many functions of the microbiota are still unclear, there is compelling experimental evidence showing that the intestinal microbiota is able to modulate carcinogenesis and the response to anticancer therapies, both in the intestinal tract and other body sites. Among the wide variety of gut-colonizing microorganisms, various species belonging to the Bifidobacterium genus are believed to elicit beneficial effects on human physiology and on the host-immune system. Recent findings, based on preclinical mouse models and on human clinical trials, have demonstrated the impact of gut commensals including bifidobacteria on the efficacy of tumor-targeting immunotherapy. Although the underlying molecular mechanisms remain obscure, bifidobacteria and other microorganisms have become a promising aid to immunotherapeutic procedures that are currently applied to treat cancer. The present review focuses on strategies to recruit the microbiome in order to enhance anticancer responses and develop therapies aimed at fighting the onset and progression of malignancies.

Oral microbiota and oral cancer: Review

In this review, we draw attention and discuss the risk factors and causes of the development of oral squamous cell carcinoma (OSCC) focusing on oral microbiota. Recently, a breakthrough in the study of cancer has been the discovery of the relationship between the presence of certain types of bacteria and the development of cancer in the human body. Studies have shown that, Porphyromonas gingivalis (P. gingivalis) bacteria that is responsible for the destructive processes in the oral cavity, could play an important role in the development of OSCC. In our continuing search for bacteria that causes oral squamous cell carcinoma, we came across the Pseudomona aeruginosa, which due to its metabolite properties, may play important role in carcinogenesis of oral cancer. One possible mechanism is the ability of Pseudomonas to synthesize nitric oxide (NO) that modulates different cancer-related appearances such as apoptosis, cell cycle, angiogenesis, invasion, and metastasis. We think that P. aeruginosa increases the concentration of NO by converting salivary nitrite to nitric oxide, and this is how it contributes to NO-related carcinogenesis. Early diagnosis and treatment of periodontitis are very important not only for patients' oral health, but also for the prevention of OSCC development. Screening test for OSCC based on determination of salivary NO levels could be appealing and may prove to be useful assay for diagnosis and early detection of disease progression in oral cancer.

Urobiome in Gender-Related Diversities of Bladder Cancer

Bladder cancer (BC) remains the most common malignancy of urinary tract. Sex-related differences in BC epidemiology, diagnosis, therapy, and outcomes have been reported. Throughout the recent years, extensive research has been devoted to genetic and molecular alterations in BC. Apart from the molecular background, another related concept which has been speculated to contribute to gender diversities in BC is the role of urinary pathogens in bladder carcinogenesis. Microbiome studies, fueled by the availability of high-throughput DNA-based techniques, have shown that perturbation in the microbiome is associated with various human diseases. The aim of this review is to comprehensively analyze the current literature according to sex-related differences in the microbiome composition in BC.

Integrating the Tumor Microenvironment into Cancer Therapy

Tumor progression is mediated by reciprocal interaction between tumor cells and their surrounding tumor microenvironment (TME), which among other factors encompasses the extracellular milieu, immune cells, fibroblasts, and the vascular system. However, the complexity of cancer goes beyond the local interaction of tumor cells with their microenvironment. We are on the path to understanding cancer from a systemic viewpoint where the host macroenvironment also plays a crucial role in determining tumor progression. Indeed, growing evidence is emerging on the impact of the gut microbiota, metabolism, biomechanics, and the neuroimmunological axis on cancer. Thus, external factors capable of influencing the entire body system, such as emotional stress, surgery, or psychosocial factors, must be taken into consideration for enhanced management and treatment of cancer patients. In this article, we review prognostic and predictive biomarkers, as well as their potential evaluation and quantitative analysis. Our overarching aim is to open up new fields of study and intervention possibilities, within the framework of an integral vision of cancer as a functional tissue with the capacity to respond to different non-cytotoxic factors, hormonal, immunological, and mechanical forces, and others inducing stroma and tumor reprogramming.

Research trends on the relationship between Microbiota and Gastric Cancer: A Bibliometric Analysis from 2000 to 2019

Background: Hundreds of studies have found that the microbiota contributes to the development of gastric cancer in the past two decades. This study aimed to access the research trends of microbiota and gastric cancer.

Materials and Methods: Publications from January 1, 2000 to December 31, 2019 were retrieved from the Web of Science Core Collection database and screened according to inclusion criteria. Different kinds of software, SPSS21.0, HistCite, VOSviewer, CiteSpace, and the online bibliometric analysis platform were used to evaluate and visualize the results.

Results: A total of 196 publications were finally identified, and the annual number of publications showed an increasing trend. These publications were from 44 countries and the USA showed its dominant position in publication outputs, H-index, total citations, and international collaborations. The journal of Helicobacter was the most productive journal. Correa P and Peek RM published the most papers, and the most productive institution was Vanderbilt University. The keyword of “Helicobacter pylori” ranked first in research frontiers and appeared earlier, and the keyword of “microbiota” began to appear in the past 3 to 5 years.

Conclusion: The annual number of publications would continue to grow. Besides the traditional Helicobacter pylori related researches, future research hotspots will focus on microbiota and its mechanism of action.

Interplay between Dietary Polyphenols and Oral and Gut Microbiota in the Development of Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed type of cancer worldwide. Dietary features play an important role in its development, and the involvement of human microbial communities in this pathology has also recently been recognized. Individuals with CRC display alterations in gut bacterial composition and a notably higher abundance of putative oral bacteria in colonic tumors. Many experimental studies and preclinical evidence propose that dietary polyphenols have a relevant role in CRC development and progression, mainly attributed to their immunomodulatory activities. Furthermore, polyphenols can modulate oral and gut microbiota, and in turn, intestinal microbes catabolize polyphenols to release metabolites that are often more active and better absorbed than the original phenolic compounds. The current study aimed to review and summarize current knowledge on the role of microbiota and the interactions between dietary polyphenols and microbiota in relation to CRC development. We have highlighted the mechanisms by which dietary polyphenols and/or their microbial metabolites exert their action on the pathogenesis and prevention of CRC as modulators of the composition and/or activity of oral and intestinal microbiota, including novel screening biomarkers and possible nutritional therapeutic implications.