Gut Microbiota Manipulation as a Tool for Colorectal Cancer Management: Recent Advances in Its Use for Therapeutic Purposes

From chaos to order: optimizing fecal microbiota transplantation for enhanced immune checkpoint inhibitors efficacy

The integration of fecal microbiota transplantation (FMT) with immune checkpoint inhibitors (ICIs) presents a promising approach for enhancing cancer treatment efficacy and overcoming therapeutic resistance. This review critically examines the controversial effects of FMT on ICIs outcomes and elucidates the underlying mechanisms. We investigate how FMT modulates gut microbiota composition, microbial metabolite profiles, and the tumor microenvironment, thereby influencing ICIs effectiveness. Key factors influencing FMT efficacy, including donor selection criteria, recipient characteristics, and administration protocols, are comprehensively discussed. The review delineates strategies for optimizing FMT formulations and systematically monitoring post-transplant microbiome dynamics. Through a comprehensive synthesis of evidence from clinical trials and preclinical studies, we elucidate the potential benefits and challenges of combining FMT with ICIs across diverse cancer types. While some studies report improved outcomes, others indicate no benefit or potential adverse effects, emphasizing the complexity of host-microbiome interactions in cancer immunotherapy. We outline critical research directions, encompassing the need for large-scale, multi-center randomized controlled trials, in-depth microbial ecology studies, and the integration of multi-omics approaches with artificial intelligence. Regulatory and ethical challenges are critically addressed, underscoring the imperative for standardized protocols and rigorous long-term safety assessments. This comprehensive review seeks to guide future research endeavors and clinical applications of FMT-ICIs combination therapy, with the potential to improve cancer patient outcomes while ensuring both safety and efficacy. As this rapidly evolving field advances, maintaining a judicious balance between openness to innovation and cautious scrutiny is crucial for realizing the full potential of microbiome modulation in cancer immunotherapy.

Advances in research on the intestinal microbiota in the mechanism and prevention of colorectal cancer (Review)

The intestinal microbiota represents a diverse population that serves a key role in colorectal cancer (CRC) and its treatment outcomes. Advancements in sequencing have revealed notable shifts in microbial composition and diversity among individuals with CRC. Concurrently, animal models have elucidated the involvement of specific microbes such as Lactobacillus fragilis, Escherichia coli and Fusobacterium nucleatum in the progression of CRC. The present review aimed to highlight contributions of intestinal microbiota to the pathogenesis of CRC, the effects of traditional treatments on intestinal microbiota and the potential for microbiota modulation as a therapeutic strategy for CRC.

Beyond the Gut: Unveiling Butyrate's Global Health Impact Through Gut Health and Dysbiosis-Related Conditions: A Narrative Review

Short-chain fatty acids (SCFAs), mainly produced by gut microbiota through the fermentation process of dietary fibers and proteins, are crucial to human health, with butyrate, a famous four-carbon SCFA, standing out for its inevitably regulatory impact on both gut and immune functions. Within this narrative review, the vital physiological functions of SCFAs were examined, with emphasis on butyrate's role as an energy source for colonocytes and its ability to enhance the gut barrier while exhibiting anti-inflammatory effects. Knowledge of butyrate synthesis, primarily generated by Firmicutes bacteria, can be influenced by diets with specifically high contents of resistant starches and fiber. Butyrate can inhibit histone deacetylase, modulate gene expression, influence immune functionality, and regulate tight junction integrity, supporting the idea of its role in gut barrier preservation. Butyrate possesses systemic anti-inflammatory properties, particularly, its capacity to reduce pro-inflammatory cytokines and maintain immune homeostasis, highlighting its therapeutic potential in managing dysbiosis and inflammatory diseases. Although butyrate absorption into circulation is typically minimal, its broader health implications are substantial, especially regarding obesity and type 2 diabetes through its influence on metabolic regulation and inflammation. Furthermore, this narrative review thoroughly examines butyrate's growing recognition as a modulator of neurological health via its interaction with the gut-brain axis. Additionally, butyrate's neuroprotective effects are mediated through activation of specific G-protein-coupled receptors, such as FFAR3 and GPR109a, and inhibition of histone deacetylases (HDACs). Research indicates that butyrate can alleviate neurological disorders, including Alzheimer's, Parkinson's, autism spectrum disorder, and Huntington's disease, by reducing neuroinflammation, enhancing neurotransmitter modulation, and improving histone acetylation. This focus will help unlock its full therapeutic potential for metabolic and neurological health, rather than exclusively on its well-known benefits for gut health, as these are often interconnected.

Small Biological Fighters Against Cancer: Viruses, Bacteria, Archaea, Fungi, Protozoa, and Microalgae

Despite the progress made in oncological theranostics, cancer remains a global health problem and a leading cause of death worldwide. Multidrug and radiation therapy resistance is an important challenge in cancer treatment. To overcome this great concern in clinical practice, conventional therapies are more and more used in combination with modern approaches to improve the quality of patients' lives. In this review, we emphasize how small biological entities, such as viruses, bacteria, archaea, fungi, protozoans, and microalgae, as well as their related structural compounds and toxins/metabolites/bioactive molecules, can prevent and suppress cancer or regulate malignant initiation, progression, metastasis, and responses to different therapies. All these small biological fighters are free-living or parasitic in nature and, furthermore, viruses, bacteria, archaea, fungi, and protozoans are components of human and animal microbiomes. Recently, polymorphic microbiomes have been recognized as a new emerging hallmark of cancer. Fortunately, there is no limit to the development of novel approaches in cancer biomedicine. Thus, viral vector-based cancer therapies based on genetically engineered viruses, bacteriotherapy, mycotherapy based on anti-cancer fungal bioactive compounds, use of protozoan parasite-derived proteins, nanoarchaeosomes, and microalgae-based microrobots have been more and more used in oncology, promoting biomimetic approaches and biology-inspired strategies to maximize cancer diagnostic and therapy efficiency, leading to an improved patients' quality of life.

Effect of colorectal cancer stem cells on the development and metastasis of colorectal cancer

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role - immune checkpoints - and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Fecal Microbiota Transplantation: Insights into Colon Carcinogenesis and Immune Regulation

Colorectal cancer (CRC) constitutes a significant global health challenge, with recent studies underscoring the pivotal role of the gut microbiome in its pathogenesis and progression. Fecal microbiota transplantation (FMT) has emerged as a compelling therapeutic approach, offering the potential to modulate microbial composition and optimize treatment outcomes. Research suggests that specific bacterial strains are closely linked to CRC, influencing both its clinical management and therapeutic interventions. Moreover, the gut microbiome's impact on immunotherapy responsiveness heralds new avenues for personalized medicine. Despite the promise of FMT, safety concerns, particularly in immunocompromised individuals, remain a critical issue. Clinical outcomes vary widely, influenced by genetic predispositions and the specific transplantation methodologies employed. Additionally, rigorous donor selection and screening protocols are paramount to minimize risks and maximize therapeutic efficacy. The current body of literature advocates for the establishment of standardized protocols and further clinical trials to substantiate FMT's role in CRC management. As our understanding of the microbiome deepens, FMT is poised to become a cornerstone in CRC treatment, underscoring the imperative for continued research and clinical validation.

Personalised medicine based on host genetics and microbiota applied to colorectal cancer

Colorectal cancer (CRC) ranks second in incidence and third in cancer mortality worldwide. This situation, together with the understanding of the heterogeneity of the disease, has highlighted the need to develop a more individualised approach to its prevention, diagnosis and treatment through personalised medicine. This approach aims to stratify patients according to risk, predict disease progression and determine the most appropriate treatment. It is essential to identify patients who may respond adequately to treatment and those who may be resistant to treatment to avoid unnecessary therapies and minimise adverse side effects. Current research is focused on identifying biomarkers such as specific mutated genes, the type of mutations and molecular profiles critical for the individualisation of CRC diagnosis, prognosis and treatment guidance. In addition, the study of the intestinal microbiota as biomarkers is being incorporated due to the growing scientific evidence supporting its influence on this disease. This article comprehensively addresses the use of current and emerging diagnostic, prognostic and predictive biomarkers in precision medicine against CRC. The effects of host genetics and gut microbiota composition on new approaches to treating this disease are discussed. How the gut microbiota could mitigate the side effects of treatment is reviewed. In addition, strategies to modulate the gut microbiota, such as dietary interventions, antibiotics, and transplantation of faecal microbiota and phages, are discussed to improve CRC prevention and treatment. These findings provide a solid foundation for future research and improving the care of CRC patients.

Inulin and Freeze-Dried Blueberry Intervention Lead to Changes in the Microbiota and Metabolites within In Vitro Studies and in Cognitive Function within a Small Pilot Trial on Healthy Children

The relationship between the gut microbiota and cognitive health is complex and bidirectional, being significantly impacted by our diet. Evidence indicates that polyphenols and inulin can impact cognitive function via various mechanisms, one of which is the gut microbiota. In this study, effects of a wild blueberry treatment (WBB) and enriched chicory inulin powder were investigated both in vitro and in vivo. Gut microbiota composition and metabolites, including neurotransmitters, were assessed upon faecal microbial fermentation of WBB and inulin in a gut model system. Secondly, microbiota changes and cognitive function were assessed in children within a small pilot (n = 13) trial comparing WBB, inulin, and a maltodextrin placebo, via a series of tests measuring executive function and memory function, with faecal sampling at baseline, 4 weeks post-intervention and after a 4 week washout period. Both WBB and inulin led to microbial changes and increases in levels of short chain fatty acids in vitro. In vivo significant improvements in executive function and memory were observed following inulin and WBB consumption as compared to placebo. Cognitive benefits were accompanied by significant increases in Faecalibacterium prausnitzii in the inulin group, while in the WBB group, Bacteroidetes significantly increased and Firmicutes significantly decreased (p < 0.05). As such, WBB and inulin both impact the microbiota and may impact cognitive function via different gut-related or other mechanisms. This study highlights the important influence of diet on cognitive function that could, in part, be mediated by the gut microbiota.

Interplay between WNT/PI3K-mTOR axis and the microbiota in APC-driven colorectal carcinogenesis: data from a pilot study and possible implications for CRC prevention

BACKGROUND

Wnt/β-catenin signalling impairment accounts for 85% of colorectal cancers (CRCs), including sporadic and familial adenomatous polyposis (FAP) settings. An altered PI3K/mTOR pathway and gut microbiota also contribute to CRC carcinogenesis. We studied the interplay between the two pathways and the microbiota composition within each step of CRC carcinogenesis.

METHODS

Proteins and target genes of both pathways were analysed by RT-qPCR and IHC in tissues from healthy faecal immunochemical test positive (FIT+, n = 17), FAP (n = 17) and CRC (n = 15) subjects. CRC-related mutations were analysed through NGS and Sanger. Oral, faecal and mucosal microbiota was profiled by 16 S rRNA-sequencing.

RESULTS

We found simultaneous hyperactivation of Wnt/β-catenin and PI3K/mTOR pathways in FAP-lesions compared to CRCs. Wnt/β-catenin molecular markers positively correlated with Clostridium_sensu_stricto_1 and negatively with Bacteroides in FAP faecal microbiota. Alistipes, Lachnospiraceae, and Ruminococcaceae were enriched in FAP stools and adenomas, the latter also showing an overabundance of Lachnoclostridium, which positively correlated with cMYC. In impaired-mTOR-mutated CRC tissues, p-S6R correlated with Fusobacterium and Dialister, the latter also confirmed in the faecal-ecosystem.

CONCLUSIONS

Our study reveals an interplay between Wnt/β-catenin and PI3K/mTOR, whose derangement correlates with specific microbiota signatures in FAP and CRC patients, and identifies new potential biomarkers and targets to improve CRC prevention, early adenoma detection and treatment.

Exploring the Relationship Between Diet, Lifestyle and Gut Microbiome in Colorectal Cancer Development: A Recent Update

Colorectal cancer (CRC) is one of the major causes of cancer-related mortality worldwide. Despite advances in treatment modalities, its prevalence continues to rise, notably among younger populations. Unhealthy dietary habits, sedentary routines, and obesity have been identified as one of the key contributors to the development of colorectal cancer, apart from genetic and epigenetic modifications. Recognizing the profound impact of diet and lifestyle on the intricate gut microbiota ecosystem offers a promising avenue for understanding CRC development and its treatment. Gut dysbiosis, characterized by imbalances favoring harmful microbes over beneficial ones, has emerged as a defining feature of CRC. Changes in diet and lifestyle can profoundly alter the composition of gut microbes and the metabolites they produce, potentially contributing to CRC onset. Focusing on recent evidence, this review discussed various dietary factors, such as high consumption of red and processed meats and low fiber intake, and lifestyle factors, including obesity, lack of physical activity, smoking, and excessive alcohol consumption, that influence the gut microbiome composition and elevate CRC risk.

Role of the Microbiome in the Diagnosis and Management of Gastroesophageal Cancers

PURPOSE

Stomach and esophageal cancers are among the highest mortality from cancers worldwide. Microbiota has an interplaying role within the human gastrointestinal (GI) tract. Dysbiosis occurs when a disruption of the balance between the microbiota and the host happens. With this narrative review, we discuss the main alterations in the microbiome of gastroesophageal cancer, revealing its potential role in the pathogenesis, early detection, and treatment.

RESULTS

Helicobacter pylori plays a major role the development of a cascade of preneoplastic conditions ranging from atrophic gastritis to metaplasia and dysplasia, ultimately culminating in gastric cancer, while other pathogenic agents are Fusobacterium nucleatum, Bacteroides fragilis, Escherichia coli, and Lactobacillus. Campylobacter species (spp.)'s role in the progression of esophageal adenocarcinoma may parallel that of Helicobacter pylori in the context of gastric cancer, with other esophageal carcinogenic agents being Escherichia coli, Bacteroides fragilis, and Fusobacterium nucleatum. Moreover, gut microbiome could significantly alter the outcomes of chemotherapy and immunotherapy. The gut microbiome can be modulated through interventions such as antibiotics, probiotics, or prebiotics intake. Fecal microbiota transplantation has emerged as a therapeutic strategy as well.

CONCLUSIONS

Nowadays, it is widely accepted that changes in the normal gut microbiome causing dysbiosis and immune dysregulation play a role gastroesophageal cancer. Different interventions, including probiotics and prebiotics intake are being developed to improve therapeutic outcomes and mitigate toxicities associated with anticancer treatment. Further studies are required in order to introduce the microbiome among the available tools of precision medicine in the field of anticancer treatment.

Positive modulation of a new reconstructed human gut microbiota by Maitake extract helpfully boosts the intestinal environment in vitro

The human gut is a complex environment where the microbiota and its metabolites play a crucial role in the maintenance of a healthy state. The aim of the present work is the reconstruction of a new in vitro minimal human gut microbiota resembling the microbe-microbe networking comprising the principal phyla (Bacillota, Bacteroidota, Pseudomonadota, and Actinomycetota), to comprehend the intestinal ecosystem complexity. In the reductionist model, we mimicked the administration of Maitake extract as prebiotic and a probiotic formulation (three strains belonging to Lactobacillus and Bifidobacterium genera), evaluating the modulation of strain levels, the release of beneficial metabolites, and their health-promoting effects on human cell lines of the intestinal environment. The administration of Maitake and the selected probiotic strains generated a positive modulation of the in vitro bacterial community by qPCR analyses, evidencing the prominence of beneficial strains (Lactiplantibacillus plantarum and Bifidobacterium animalis subsp. lactis) after 48 hours. The bacterial community growths were associated with the production of metabolites over time through GC-MSD analyses such as lactate, butyrate, and propionate. Their effects on the host were evaluated on cell lines of the intestinal epithelium and the immune system, evidencing positive antioxidant (upregulation of SOD1 and NQO1 genes in HT-29 cell line) and anti-inflammatory effects (production of IL-10 from all the PBMCs). Therefore, the results highlighted a positive modulation induced by the synergic activities of probiotics and Maitake, inducing a tolerogenic microenvironment.

High-fat diet disrupts the gut microbiome, leading to inflammation, damage to tight junctions, and apoptosis and necrosis in Nyctereutes procyonoides intestines

Given the burgeoning Nyctereutes procyonoides breeding industry and its growing scale, it is imperative to investigate the impact of high-fat diets on the health of these animals. This study involved 30 male Nyctereutes procyonoides of comparable weights (3 kg ±0.5), randomly assigned to either a control group or a high-fat diet group (n = 15 each). The latter group was fed a mixture of lard and basal diet in a 2:5 ratio, establishing a high-fat diet model in Nyctereutes procyonoides. This diet induced diarrhea and histopathological changes in the Nyctereutes procyonoides. Analysis of the small intestine contents using 16S rRNA sequencing revealed a high-fat diet-induced disruption in the gut microbiota. Specifically, Escherichia-Shigella emerged as the biomarker in the high-fat diet group (P = 0.049), while Vagococcus was prevalent in the control group (P = 0.049), indicating a significant increase in harmful bacteria in the high-fat diet group. Furthermore, this disrupted gut flora correlated with inflammation and oxidative stress, as evidenced by marked increases in TNF-α (P < 0.01), IL-1β (P < 0.05), and IL-6 (P < 0.05) levels, measured via q-PCR, Western blot, and oxidative stress assays. In addition, q-PCR analysis revealed significant upregulation of apoptosis and necrosis markers, including Bax, Caspase3, Caspase9, Caspase12, RIPK3, and RIPK1 (P < 0.01 to P < 0.001), and a concurrent downregulation of the anti-apoptotic gene Bcl-2 (P < 0.01) in the high-fat diet group, consistent with protein expression trends. These findings suggest that a high-fat diet alters the gut microbiome toward a more harmful bacterial composition, escalating inflammatory responses and intestinal tissue permeability, culminating in intestinal cell apoptosis and necrosis.IMPORTANCEThis study examines the impact of high-fat diets on Nyctereutes procyonoides. Our research established a Nyctereutes procyonoides model on a high-fat diet, revealing significant health impacts, such as diarrhea, histological anomalies, and alterations in the gut microbiota. These findings emphasize the importance of preventing health issues and promoting sustainable industry growth. They highlight the significant impact of diet on gut microbiota and overall animal health.

The State-of-the-Art Mechanisms and Antitumor Effects of Somatostatin in Colorectal Cancer: A Review

Somatostatin, a somatotropin release inhibiting factor (SST, SRIF), is a widely distributed multifunctional cyclic peptide and acts through a transmembrane G protein-coupled receptor (SST1-SST5). Over the past decades, research has begun to reveal the molecular mechanisms underlying the anticancer activity of this hormonal peptide. Among gastrointestinal tract (GIT) tumors, direct and indirect antitumor effects of SST have been documented best in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) and less well in non-endocrine cancers, including sporadic colorectal cancer (CRC). In the latter, the signaling pathways involved in the antitumor function of SST are primarily MAPK/ERK/AKT and Wnt/β-catenin. Direct (involving the MAPK pathway) and indirect (VEGF production) antiangiogenic effects of SST in CRC have also been described. The anti-inflammatory role of SST in CRC is emphasized, but detailed molecular mechanisms are still being explored. The role of SST in tumor genome/tumor microenvironment (TME)/host's gut microbiome interactions is only partially known. The results of SST analogues (SSAs)' treatment of sporadic CRC in monotherapy in vivo are not spectacular. The current review aims to present the state-of-the-art mechanisms and antitumor activity of endogenous SST and its synthetic analogues in CRC, with particular emphasis on sporadic CRC.

Acute pancreatitis is associated with gut dysbiosis in children

BACKGROUND

Pediatric acute pancreatitis (AP) is associated with significant morbidity. Therefore, improved understanding of children who will develop severe AP is critical. Adult studies have reported AP associated gut dysbiosis, but pediatric studies are lacking.

AIMS

Assess stool microbial taxonomic and functional profiles of children with first attack of AP compared to those of healthy controls (HC), and between mild and severe AP METHODS: Children under 21 years hospitalized at a tertiary center (n = 30) with first AP attack were recruited including HC (n = 34) from same region. Shotgun metagenomic sequencing was performed on extracted DNA.

RESULTS

Demographics were similar between AP and HC. Alpha diversity (-0.68 ± 0.13, p-value < 0.001), and beta-diversity (R2=0.13, p-value < 0.001) differed, in children with AP compared to HC. Species including R.gnavus, V.parvula, E.faecalis, C.innocuum were enriched in AP. MetaCyc pathways involved in amino acid metabolism and fatty acid beta-oxidation were enriched in AP. Beta-diversity (R2=0.06, p-value = 0.02) differed for severe AP compared to mild AP with enrichment in E.faecalis and C.citroniae.

CONCLUSIONS

Gut dysbiosis occurs in pediatric AP and is associated with AP severity. A multicenter study confirming these findings could pave way for interventional trials manipulating the gut microbiome to mitigate AP severity.

A perspective on emerging therapies in metastatic colorectal cancer: Focusing on molecular medicine and drug resistance

The majority of cancer cases are colorectal cancer, which is also the second largest cause of cancer-related deaths worldwide. Metastasis is the leading cause of death for patients with colorectal cancer. Metastatic colorectal cancer incidence are on the rise due to a tiny percentage of tumors developing resistant to medicines despite advances in treatment tactics. Cutting-edge targeted medications are now the go-to option for customized and all-encompassing CRC care. Specifically, multitarget kinase inhibitors, antivascular endothelial growth factors, and epidermal growth factor receptors are widely used in clinical practice for CRC-targeted treatments. Rare targets in metastatic colorectal cancer are becoming more well-known due to developments in precision diagnostics and the extensive use of second-generation sequencing technology. These targets include the KRAS mutation, the BRAF V600E mutation, the HER2 overexpression/amplification, and the MSI-H/dMMR. Incorporating certain medications into clinical trials has significantly increased patient survival rates, opening new avenues and bringing fresh viewpoints for treating metastatic colorectal cancer. These focused therapies change how cancer is treated, giving patients new hope and better results. These markers can significantly transform and individualize therapy regimens. They could open the door to precisely customized and more effective medicines, improving patient outcomes and quality of life. The fast-growing body of knowledge regarding the molecular biology of colorectal cancer and the latest developments in gene sequencing and molecular diagnostics are directly responsible for this advancement.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.

Exploring the Relationship between the Gut Mucosal Virome and Colorectal Cancer: Characteristics and Correlations

The fecal virome has been reported to be associated with CRC. However, little is known about the mucosal virome signature in CRC. This study aimed to determine the viral community within CRC tissues and their contributions to colorectal carcinogenesis. Colonic mucosal biopsies were harvested from patients with CRC (biopsies of both neoplasia and adjacent normal tissue (CRC-A)) and healthy controls (HC). The shot-gun metagenomic sequencing of virus-like particles (VLPs) was performed on the biopsies. Viral community, functional pathways, and their correlations to clinical data were analyzed. Fluorescence in situ hybridizations (FISH) for the localization of viruses in the intestine was performed, as well as quantitative PCR for the detection of Torque teno virus load in human mucosal VLP DNA. A greater number and proportion of core species were found in CRC tissues than in CRC-A and HC tissues. The diversity of the mucosal virome in CRC tissues was significantly increased compared to that in HC and CRC-A tissues. The mucosal virome signature of CRC tissues were significantly different from those of HC and CRC-A tissues at the species level. The abundances of eukaryotic viruses from the Anelloviridae family and its sub-species Torque teno virus (TTV) were significantly higher in CRC patients than in HC. Furthermore, increased levels of TTV in the intestinal lamina propria were found in the CRC group. Multiple viral functions of TTV associated with carcinogenesis were enriched in CRC tissues. We revealed for the first time that the mucosal virobiota signature of CRC is characterized by a higher diversity and more eukaryotic viruses. The enrichment of TTV species in CRC tissues suggests that they may play an oncogenic role in CRC. Targeting eukaryotic viruses in the gut may provide novel strategies for the prevention and treatment of CRC.

Gut Microbiome Composition and Its Metabolites Are a Key Regulating Factor for Malignant Transformation, Metastasis and Antitumor Immunity

The genetic and metabolomic abundance of the microbiome exemplifies that the microbiome comprises a more extensive set of genes than the entire human genome, which justifies the numerous metabolic and immunological interactions between the gut microbiota, macroorganisms and immune processes. These interactions have local and systemic impacts that can influence the pathological process of carcinogenesis. The latter can be promoted, enhanced or inhibited by the interactions between the microbiota and the host. This review aimed to present evidence that interactions between the host and the gut microbiota might be a significant exogenic factor for cancer predisposition. It is beyond doubt that the cross-talk between microbiota and the host cells in terms of epigenetic modifications can regulate gene expression patterns and influence cell fate in both beneficial and adverse directions for the host's health. Furthermore, bacterial metabolites could shift pro- and anti-tumor processes in one direction or another. However, the exact mechanisms behind these interactions are elusive and require large-scale omics studies to better understand and possibly discover new therapeutic approaches for cancer.

Therapeutic potential and nutritional significance of Ganoderma lucidum - a comprehensive review from 2010 to 2022

With a long history in traditional Asian medicine, Ganoderma lucidum (G. lucidum) is a mushroom species suggested to improve health and extend life. Its medicinal reputation has merited it with numerous attributes and titles, and it is evidenced to be effective in the prevention and treatment of various metabolic disorders owing to its unique source of bioactive metabolites, primarily polysaccharides, triterpenoids, and polyphenols, attributed with antioxidant, anti-inflammatory, anticancer, hepatoprotective, antidiabetic activities, etc. These unique potential pharmaceutical properties have led to its demand as an important resource of nutrient supplements in the food industry. It is reported that the variety of therapeutic/pharmacological properties was mainly due to its extensive prebiotic and immunomodulatory functions. All literature summarized in this study was collated based on a systematic review of electronic libraries (PubMed, Scopus databases, Web of Science Core Collection, and Google Scholar) from 2010-2022. This review presents an updated and comprehensive summary of the studies on the immunomodulatory therapies and nutritional significance of G. lucidum, with the focus on recent advances in defining its immunobiological mechanisms and the possible applications in the food and pharmaceutical industries for the prevention and management of chronic diseases. In addition, toxicological evidence and the adoption of standard pharmaceutical methods for the safety assessment, quality assurance, and efficacy testing of G. lucidum-derived compounds will be the gateway to bringing them into health establishments.

Antibiotics, the microbiome and gastrointestinal cancers: A causal interference?

Our understanding of the gut microbiota has significantly evolved over the last two decades. Advances in the analysis of the gut microbiome continues to reveal complex microbial communities and discoveries about their role in health and diseases, including cancer development, are continuously growing. In addition, research has demonstrated that the use of antibiotics can modulate the gut microbiota composition negatively and influence cancer treatment outcomes, suggesting that antibiotics should be avoided if possible. In this article, we review the role of the gut microbiota in the formation of GI cancers. We show that specific bacterial populations can positively or negatively affect cancer formation with specific attention given to gastric and colorectal cancer. We also review the role of microbial-targeted therapies on cancer treatment outcomes.

Identification of the effect and mechanism of Yiyi Fuzi Baijiang powder against colorectal cancer using network pharmacology and experimental validation

Background: Yiyi Fuzi Baijiang powder (YFBP) is a traditional Chinese medicine used to treat colorectal cancer, although its bioactivity and mechanisms of action have not been studied in depth yet. The study intended to identify the potential targets and signaling pathways affected by YFBP during the treatment of colorectal cancer through pharmacological network analysis and to further analyze its chemical compositions and molecular mechanisms of action. Methods: The Traditional Chinese Medicine Systems Pharmacology (TCMSP), Traditional Chinese Medicine Integrated Database (TCMID), HitPredict (HIT), and Search Tool for Interactions of Chemicals (STITCH) databases were used to screen the bioactive components and promising targets of YFBP. Targets related to colorectal cancer were retrieved from the GeneCards and Gene Ontology databases. Cytoscape software was used to construct the "herb-active ingredient-target" network. The STRING database was used to construct and analyze protein-protein interactions (PPIs). Afterward, the R packages clusterProfiler and Cytoscape Hub plug-in were used to perform Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of target genes. The results of the network pharmacological analysis were also experimentally validated. Results: In total, 33 active components and 128 target genes were screened. Among them, 46 target genes were considered potential therapeutic targets that crossed the CRC target genes. The network pharmacology analysis showed that the active components of YFBP were correlated positively with CRC inflammatory target genes such as TLR4, TNF, and IL-6. The inflammation-related signaling pathways affected by the active components included the TNF-α, interleukin-17, and toll-like receptor signaling pathways. The active ingredients of YFBP, such as luteolin, β-sitosterol, myristic acid, and vanillin, may exert anti-tumor effects by downregulating SMOX expression via anti-inflammatory signaling and regulation of the TLR4/NF-κB signaling pathway. Conclusion: In the present study, the potential active components, potential targets, and key biological pathways involved in the YFBP treatment of CRC were determined, providing a theoretical foundation for further anti-tumor research.

Poria cocos polysaccharides exert prebiotic function to attenuate the adverse effects and improve the therapeutic outcome of 5-FU in ApcMin/+ mice

BACKGROUND

As a first-line chemotherapeutic agent, 5-fluorouracil (5-FU) exhibits many side effects, weakening its efficacy in cancer treatment. In this study, we hypothesize that Poria cocos polysaccharides (PCP), a traditional Chinese herbal medicine with various bioactivities and prebiotic effects, might improve the therapeutic effect of 5-FU by restoring the homeostasis of the gut microenvironment and the commensal gut microflora.

METHODS

Apc^Min/+ mice were employed to evaluate the anti-cancer effect of 5-FU in conjunction with PCP treatment. Body weight and food consumption were monitored weekly. Polyp count was used to assess the anti-cancer effect of PCP and 5-FU. Expressions of mucosal cytokines and gut epithelial junction molecules were measured using qRT-PCR. 16S rRNA gene sequencing of fecal DNAs was used to evaluate the compositional changes of gut microbiota (GM). Transplantation of Lactobacillus johnsonii and Bifidobacterium animalis were performed to verify the prebiotic effects of PCP in improving the efficacy of 5-FU.

RESULTS

The results showed that PCP treatment alleviated the weight loss caused by 5-FU treatment and reduced the polyp burden in Apc^Min/+ mice. Additionally, PCP treatment eased the cytotoxic effects of 5-FU by reducing the expressions of pro-inflammatory cytokines, increasing the anti-inflammatory cytokines; and significantly improving the gut barriers by enhancing the tight junction proteins and associated adhesion molecules. Furthermore, 16S rRNA gene sequencing data showed that PCP alone or with 5-FU could stimulate the growth of probiotic bacteria (Bacteroides acidifaciens, Bacteroides intestinihominis, Butyricicoccus pullicaecorum, and the genera Lactobacillus, Bifidobacterium, Eubacterium). At the same time, it inhibited the growth of potential pathogens (e.g., Alistipes finegoldii, Alistipes massiliensis, Alistipes putredinis., Citrobacter spp., Desulfovibrio spp., and Desulfovibrio desulfuricans). Moreover, the results showed that transplantation of L.johnsonii and B.animalis effectively reduced the polyp burden in Apc^Min/+ mice being treated with 5-FU.

CONCLUSION

Our study showed that PCP could effectively improve the anti-cancer effect of 5-FU by attenuating its side effects, modulating intestinal inflammation, improving the gut epithelial barrier, and modulating the gut microbiota of Apc^Min/+ mice.

Gut microbiota: An emerging therapeutic approach of herbal medicine for prevention of colorectal cancer

The gut dysbiosis has emerged as a prominent player in the pathogenesis and development of colorectal cancer (CRC), which in turn intensifies dysregulated gut microbiota composition and inflammation. Since most drugs are given orally, this dysbiosis directly and indirectly impinges the absorption and metabolism of drugs in the gastrointestinal tract, and subsequently affects the clinical outcome of patients with CRC. Herbal medicine, including the natural bioactive products, have been used traditionally for centuries and can be considered as novel medicinal sources for anticancer drug discovery. Due to their various structures and pharmacological effects, natural products have been found to improve microbiota composition, repair intestinal barrier and reduce inflammation in human and animal models of CRC. This review summarizes the chemo-preventive effects of extracts and/or compounds derived from natural herbs as the promising antineoplastic agents against CRC, and will provide innovative strategies to counteract dysregulated microbiota and improve the lives of CRC patients.

The role of microbiota in colorectal cancer

Cancer is one of the most important causes of death throughout the world, and the mortality rate is increasing significantly due to the aging of the population. One of the most common types of cancer is colorectal cancer (CRC). Human microbial ecosystems use metabolism to make important impacts on the body physiology. An intensive literature review was made to investigate the correlations between human gut microbiota and the incidence of CRC. The results of these studies show that there are differences in the composition of microbiota between CRC patients and normal people and the microorganisms in CRC patients are very different from healthy individuals. Therefore, changes in the microbiome can be used as a biomarker for the early detection of CRC. On the other hand, the intestinal flora is may be act as a powerful weapon against CRC in the future.

Roles of gut microbiota in colorectal carcinogenesis providing a perspective for early diagnosis and treatment

Colorectal cancer (CRC) is the third most prevalent malignant neoplasm in the world. CRC is influenced by both environmental and genetic factors. Through toxin-mediated DNA damage and promotion of persistent dysregulated inflammation, the gut microbiota plays a crucial role in the development of CRC. In this review, we discussed the correlation between the bacterial microbiota and CRC carcinogenesis as well as the mechanism by which Streptococcus bovis/gallolyticus, Fusobacterium nucleatum, Bacteroides fragilis, and Escherichia coli can cause CRC.

Correlation between green tea polyphenols regulating intestinal bacteriophage and flora diversity in SPF mice

Green tea polyphenols (GTP) play an important role in shaping the gut microbiome, comprising of a range of densely colonizing microorganisms, including bacteriophages. Previous studies focused on the effect of...

Microbiota-targeted therapies in inflammation resolution

Gut microbiota has been shown to systemically shape the immunological landscape, modulate homeostasis and play a role in both health and disease. Dysbiosis of gut microbiota promotes inflammation and contributes to the pathogenesis of several major disorders in gastrointestinal tract, metabolic, neurological and respiratory diseases. Much effort is now focused on understanding host-microbes interactions and new microbiota-targeted therapies are deeply investigated as a means to restore health or prevent disease. This review details the immunoregulatory role of the gut microbiota in health and disease and discusses the most recent strategies in manipulating individual patient's microbiota for the management and prevention of inflammatory conditions.

Supplementation of Probiotic Butyricicoccus pullicaecorum Mediates Anticancer Effect on Bladder Urothelial Cells by Regulating Butyrate-Responsive Molecular Signatures

In bladder cancer, urothelial carcinoma is the most common histologic subtype, accounting for more than 90% of cases. Pathogenic effects due to the dysbiosis of gut microbiota are localized not only in the colon, but also in regulating bladder cancer distally. Butyrate, a short-chain fatty acid produced by gut microbial metabolism, is mainly studied in colon diseases. Therefore, the resolution of the anti-cancer effects of butyrate-producing microbes on bladder urothelial cells and knowledge of the butyrate-responsive molecules must have clinical significance. Here, we demonstrate a correlation between urothelial cancer of the bladder and Butyricicoccus pullicaecorum. This butyrate-producing microbe or their metabolite, butyrate, mediated anti-cancer effects on bladder urothelial cells by regulating cell cycle, cell growth, apoptosis, and gene expression. For example, a tumor suppressor against urothelial cancer of the bladder, bladder cancer-associated protein, was induced in butyrate-treated HT1376 cells, a human urinary bladder cancer cell line. In conclusion, urothelial cancer of the bladder is a significant health problem. To improve the health of bladder urothelial cells, supplementation of B. pullicaecorum may be necessary and can further regulate butyrate-responsive molecular signatures.

Gut Microbiota-Derived Metabolites in Colorectal Cancer: The Bad and the Challenges

Accumulating evidence from studies in humans and animal models has elucidated that gut microbiota, acting as a complex ecosystem, contributes critically to colorectal cancer (CRC). The potential mechanisms often reported emphasize the vital role of carcinogenic activities of specific pathogens, but in fact, a series of metabolites produced from exogenous dietary substrates or endogenous host compounds occupy a decisive position similarly. Detrimental gut microbiota-derived metabolites such as trimethylamine-N-oxide, secondary bile acids, hydrogen sulfide and N-nitroso compounds could reconstruct the ecological composition and metabolic activity of intestinal microorganisms and formulate a microenvironment that opens susceptibility to carcinogenic stimuli. They are implicated in the occurrence, progression and metastasis of CRC through different mechanisms, including inducing inflammation and DNA damage, activating tumorigenic signaling pathways and regulating tumor immunity. In this review, we mainly summarized the intimate relationship between detrimental gut microbiota-derived metabolites and CRC, and updated the current knowledge about detrimental metabolites in CRC pathogenesis. Then, multiple interventions targeting these metabolites for CRC management were critically reviewed, including diet modulation, probiotics/prebiotics, fecal microbiota transplantation, as well as more precise measures such as engineered bacteria, phage therapy and chemopreventive drugs. A better understanding of the interplay between detrimental microbial metabolites and CRC would hold great promise against CRC.

Microbiota-Immune Interactions in Ulcerative Colitis and Colitis Associated Cancer and Emerging Microbiota-Based Therapies

Ulcerative colitis (UC) is a chronic autoimmune disorder affecting the colonic mucosa. UC is a subtype of inflammatory bowel disease along with Crohn's disease and presents with varying extraintestinal manifestations. No single etiology for UC has been found, but a combination of genetic and environmental factors is suspected. Research has focused on the role of intestinal dysbiosis in the pathogenesis of UC, including the effects of dysbiosis on the integrity of the colonic mucosal barrier, priming and regulation of the host immune system, chronic inflammation, and progression to tumorigenesis. Characterization of key microbial taxa and their implications in the pathogenesis of UC and colitis-associated cancer (CAC) may present opportunities for modulating intestinal inflammation through microbial-targeted therapies. In this review, we discuss the microbiota-immune crosstalk in UC and CAC, as well as the evolution of microbiota-based therapies.

Tumorigenic bacteria in colorectal cancer: mechanisms and treatments

Colorectal cancer (CRC) is the third most common and the second most fatal cancer. In recent years, more attention has been directed toward the role of gut microbiota in the initiation and development of CRC. Some bacterial species, such as Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis, Enterococcus faecalis, and Salmonella sp. have been associated with CRC, based upon sequencing studies in CRC patients and functional studies in cell culture and animal models. These bacteria can cause host DNA damage by genotoxic substances, including colibactin secreted by pks + Escherichia coli, B. fragilis toxin (BFT) produced by Bacteroides fragilis, and typhoid toxin (TT) from Salmonella. These bacteria can also indirectly promote CRC by influencing host-signaling pathways, such as E-cadherin/β-catenin, TLR4/MYD88/NF-κB, and SMO/RAS/p38 MAPK. Moreover, some of these bacteria can contribute to CRC progression by helping tumor cells to evade the immune response by suppressing immune cell function, creating a proinflammatory environment, or influencing the autophagy process. Treatments with the classical antibacterial drugs, metronidazole or erythromycin, the antibacterial active ingredients, M13@ Ag (electrostatically assembled from inorganic silver nanoparticles and the protein capsid of bacteriophage M13), berberine, and zerumbone, were found to inhibit tumorigenic bacteria to different degrees. In this review, we described progress in elucidating the tumorigenic mechanisms of several CRC-associated bacteria, as well as progress in developing effective antibacterial therapies. Specific bacteria have been shown to be active in the oncogenesis and progression of CRC, and some antibacterial compounds have shown therapeutic potential in bacteria-induced CRC. These bacteria may be useful as biomarkers or therapeutic targets for CRC.

Challenges in Determining the Role of Microbiome Evolution in Barrett's Esophagus and Progression to Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) claims the lives of half of patients within the first year of diagnosis, and its incidence has rapidly increased since the 1970s despite extensive research into etiological factors. The changes in the microbiome within the distal esophagus in modern populations may help explain the growth in cases that other common EAC risk factors together cannot fully explain. The precursor to EAC is Barrett's esophagus (BE), a metaplasia adapted to a reflux-mediated microenvironment that can be challenging to diagnose in patients who do not undergo endoscopic screening. Non-invasive procedures to detect microbial communities in saliva, oral swabs and brushings from the distal esophagus allow us to characterize taxonomic differences in bacterial population abundances within patients with BE versus controls, and may provide an alternative means of BE detection. Unique microbial communities have been identified across healthy esophagus, BE, and various stages of progression to EAC, but studies determining dynamic changes in these communities, including migration from proximal stomach and oral cavity niches, and their potential causal role in cancer formation are lacking. Helicobacter pylori is negatively associated with EAC, and the absence of this species has been implicated in the evolution of chromosomal instability, a main driver of EAC, but joint analyses of microbiome and host genomes are needed. Acknowledging technical challenges, future studies on the prediction of microbial dynamics and evolution within BE and the progression to EAC will require larger esophageal microbiome datasets, improved bioinformatics pipelines, and specialized mathematical models for analysis.

Cell-based immunotherapy approaches for colorectal cancer: main achievements and challenges

Immunotherapy is becoming as a major treatment modality for multiple types of solid tumors, including subsets of colorectal cancers (CRCs). The successes with immunotherapy alone has largely been achieved in patients with advanced-stage mismatch-repair-deficient and microsatellite instability-high (dMMR-MSI-H) CRCs. However, the benefits of immunotherapy have not been demonstrated to be effective in patients with proficient mismatch repair (pMMR) CRC, who are microsatellite-stable (MSS) or have low levels of microsatellite instability (MSI-L). Here, we provide a comprehensive review on the immune microenvironment of CRC tumors and describe the rapid pace of scientific changes. We discuss the tremendous promise of cell-based immunotherapy strategies that are under preclinical studies/clinical trials or being used in therapeutic paradigms.

Familial adenomatous polyposis and changes in the gut microbiota: New insights into colorectal cancer carcinogenesis

Patients with familial adenomatous polyposis (FAP), an autosomal dominant hereditary colorectal cancer syndrome, have a lifetime risk of developing cancer of nearly 100%. Recent studies have pointed out that the gut microbiota could play a crucial role in the development of colorectal adenomas and the consequent progression to colorectal cancer. Some gut bacteria, such as Fusobacterium nucleatum, Escherichia coli, Clostridium difficile, Peptostreptococcus, and enterotoxigenic Bacteroides fragilis, could be implicated in colorectal carcinogenesis through different mechanisms, including the maintenance of a chronic inflammatory state, production of bioactive tumorigenic metabolites, and DNA damage. Studies using the adenomatous polyposis coliMin/+ mouse model, which resembles FAP in most respects, have shown that specific changes in the intestinal microbial community could influence a multistep progression, the intestinal "adenoma-carcinoma sequence", which involves mucosal barrier injury, low-grade inflammation, activation of the Wnt pathway. Therefore, modulation of gut microbiota might represent a novel therapeutic target for patients with FAP. Administration of probiotics, prebiotics, antibiotics, and nonsteroidal anti-inflammatory drugs could potentially prevent the progression of the adenoma-carcinoma sequence in FAP. The aim of this review was to summarize the best available knowledge on the role of gut microbiota in colorectal carcinogenesis in patients with FAP.

Ganoderma lucidum polysaccharide modulates gut microbiota and immune cell function to inhibit inflammation and tumorigenesis in colon

This study investigated the effects of water-soluble polysaccharide extracted from the sporoderm-removed spores of Ganoderma lucidum (GLP) against AOM/DSS-induced inflammation, tumorigenesis, and gut microbiota modification, which has never been reported before. Our data revealed that GLP (200 and 300 mg/kg) decreased AOM/DSS-induced colitis and tumorigenesis, manifested by significantly reduced disease activity index score, and total number and size of tumors. Furthermore, GLP ameliorated AOM/DSS-induced microbiota dysbiosis, increased short-chain fatty acid production, and alleviated endotoxemia by inhibiting TLR4/MyD88/NF-κB signaling. Besides, GLP profoundly improved gut barrier function as evidenced by increased numbers of goblet cells, MUC2 secretion, and tight junction protein expressions. GLP treatment inhibited macrophage infiltration and downregulated IL-1β, iNOS, and COX-2 expressions. Additionally, GLP inhibited lipopolysaccharides (LPS)-induced inflammation markers and MAPK (JNK and ERK) activation in macrophage RAW264.7, intestinal HT-29, and NCM460 cells. In conclusion, these results indicate that GLP is a promising prebiotic for the treatment of colorectal cancer.

Postbiotics, Metabolic Signaling, and Cancer

Postbiotics are health-promoting microbial metabolites delivered as a functional food or a food supplement. They either directly influence signaling pathways of the body or indirectly manipulate metabolism and the composition of intestinal microflora. Cancer is the second leading cause of death worldwide and even though the prognosis of patients is improving, it is still poor in the substantial part of the cases. The preventable nature of cancer and the importance of a complex multi-level approach in anticancer therapy motivate the search for novel avenues of establishing the anticancer environment in the human body. This review summarizes the principal findings demonstrating the usefulness of both natural and synthetic sources of postbotics in the prevention and therapy of cancer. Specifically, the effects of crude cell-free supernatants, the short-chain fatty acid butyrate, lactic acid, hydrogen sulfide, and β-glucans are described. Contradictory roles of postbiotics in healthy and tumor tissues are highlighted. In conclusion, the application of postbiotics is an efficient complementary strategy to combat cancer.

Antibiotic-associated dysbiosis affects the ability of the gut microbiota to control intestinal inflammation upon fecal microbiota transplantation in experimental colitis models

BACKGROUND

The gut microbiota plays a central role in host physiology and in several pathological mechanisms in humans. Antibiotics compromise the composition and functions of the gut microbiota inducing long-lasting detrimental effects on the host. Recent studies suggest that the efficacy of different clinical therapies depends on the action of the gut microbiota. Here, we investigated how different antibiotic treatments affect the ability of the gut microbiota to control intestinal inflammation upon fecal microbiota transplantation in an experimental colitis model and in ex vivo experiments with human intestinal biopsies.

RESULTS

Murine fecal donors were pre-treated with different antibiotics, i.e., vancomycin, streptomycin, and metronidazole before FMT administration to colitic animals. The analysis of the gut microbiome, fecal metabolome, and the immunophenotyping of colonic lamina propria immune cells revealed that antibiotic pre-treatment significantly influences the capability of the microbiota to control intestinal inflammation. Streptomycin and vancomycin-treated microbiota failed to control intestinal inflammation and were characterized by the blooming of pathobionts previously associated with IBD as well as with metabolites related to the presence of oxidative stress and metabolism of simple sugars. On the contrary, the metronidazole-treated microbiota retained its ability to control inflammation co-occurring with the enrichment of Lactobacillus and of innate immune responses involving iNKT cells. Furthermore, ex vivo cultures of human intestinal lamina propria mononuclear cells and iNKT cell clones from IBD patients with vancomycin pre-treated sterile fecal water showed a Th1/Th17 skewing in CD4⁺ T-cell populations; metronidazole, on the other hand, induced the polarization of iNKT cells toward the production of IL10.

CONCLUSIONS

Diverse antibiotic regimens affect the ability of the gut microbiota to control intestinal inflammation in experimental colitis by altering the microbial community structure and microbiota-derived metabolites. Video Abstract.

Oral microbiota and vitamin D impact on oropharyngeal squamous cell carcinogenesis: a narrative literature review

An emerging body of research is revealing the microbiota pivotal involvement in determining the health or disease state of several human niches, and that of vitamin D also in extra-skeletal regions. Nevertheless, much of the oral microbiota and vitamin D reciprocal impact in oropharyngeal squamous cell carcinogenesis (OPSCC) is still mostly unknown. On this premise, starting from an in-depth scientific bibliographic analysis, this narrative literature review aims to show a detailed view of the state of the art on their contribution in the pathogenesis of this cancer type. Significant differences in the oral microbiota species quantity and quality have been detected in OPSCC-affected patients; in particular, mainly high-risk human papillomaviruses (HR-HPVs), Fusobacterium nucleatum, Porphyromonas gingivalis, Pseudomonas aeruginosa, and Candida spp. seem to be highly represented. Vitamin D prevents and fights infections promoted by the above identified pathogens, thus confirming its homeostatic function on the microbiota balance. However, its antimicrobial and antitumoral actions, well-described for the gut, have not been fully documented for the oropharynx yet. Deeper investigations of the mechanisms that link vitamin D levels, oral microbial diversity and inflammatory processes will lead to a better definition of OPSCC risk factors for the optimization of specific prevention and treatment strategies.

Gut eukaryotic virome in colorectal carcinogenesis: Is that a trigger?

The human gut microbiota is composed of bacteria and viruses that might be associated with colorectal cancer (CRC) onset and progression. Indeed, although viral infections have been reported to be the primary trigger in many diseases, the role of eukaryotic viruses populating the gut mucosa during early colorectal carcinogenesis is underinvestigated. Human eukaryotic viruses in the gut were found to induce alterations of the immune homeostasis so that some viral-dependent mechanisms likely able to induce DNA alterations in the bowel wall have been proposed, although no demonstration is available yet. However, thanks to the latest advancements in computational biology and the implementation of the bioinformatic pipelines, the option of establishing a direct causative link between intestinal virome and CRC will be possible soon, hopefully paving the way to innovative therapeutic strategies blocking or reverting the CRC pathogenesis.