Possible role of Porphyromonas gingivalis in orodigestive cancers

Exploring preventive and treatment strategies for oral cancer: Modulation of signaling pathways and microbiota by probiotics

The evidence suggests that the microbiome plays a crucial role in cancer development. The oral cavity has many microorganisms that can influence oral cancer progression. Understanding the mechanisms and signaling pathways of the oral, gum, and teeth microbiome in tumor progression can lead to new treatment strategies. Probiotics, which are friendly microorganisms, have shown potential as anti-cancer agents. These positive characteristics of probiotic strains make them suitable for cancer prevention or treatment. The oral-gut microbiome axis supports health and homeostasis, and imbalances in the oral microbiome can disrupt immune signaling pathways, epithelial barriers, cell cycles, apoptosis, genomic stability, angiogenesis, and metabolic processes. Changes in the oral microbiome in oral cancer may suggest using probiotics-based treatments for their direct or indirect positive roles in cancer development, progression, and metastasis, specifically oral squamous cell carcinoma (OSCC). Here, reported relationships between probiotics, oral microbiota, and oral cancer are summarized.

Comparative analysis of bacterial abundance and diversity in tumour tissue of oral squamous cell carcinoma and non-tumour tissue: insights from a systematic review of 16S ribosomal RNA sequencing

BACKGROUND

As per the recent research findings, there is a significant difference between the bacteriome of normal tissue (NT) and tumor tissues (TT) of oral squamous cell carcinoma (OSCC). Identifying this distinct bacteriome is crucial for understanding their potential contribution to oral carcinogenesis. This systematic review (SR) aims to identify exclusive and relative bacterial abundance and bacterial diversity in TT and NT.

METHODOLOGY

The review was conducted following the PRISMA guidelines. PUBMED and SCOPUS databases were searched for studies in English published till 31st August 2024. The inclusion criteria focused on identifying bacteriome in NT versus TT at either species,/genus, and/or phylum level through 16 s ribosomal RNA sequencing. Quality assessment was performed using an eleven-parameter tool combining the Newcastle-Ottawa Scale and customized criteria.

RESULT

Evaluating the selected 13 articles, we have identified the exclusive and relative abundance of bacteriome in TT and NT at phylum, genus, and species levels. Three phyla such as Chloroflexota, Deinococcus-Thermus, and Mycoplasmatota, are found exclusively in TT. Seven genus such as Eubacterium, Campylobacter, Aeromonas, Oceanivigra, Rheinheimera, Weissella, and Catonella are exclusively found in TT. Ten species such as Micrococcus luteus, Prevotella melaninogenica, Exiguobacterium oxidotolerans, Fusobacterium naviforme, Staphylococcus aureus, Veillonella parvula, Parvimonas sp oral taxon 110, Eubacterium II G1 infirmum, Eubacterium XI G3 Brachy, Weissella viridescens are found in TT. Six genus such as Capnocytophaga, Selenomonas, Leptothrix, Desulfovibrio, Desulfoplanes, Pelospora are found exclusively in NT. Eleven species, such as Streptococcus sp. Oral taxon 071,Selenomonas sputigena, Treponema pedis, Acholeplasmatales bacterium, Capnocytophaga haemolytica, Eubacterium sp., Syntrophomonadaceae genomosp.,Treponema putidum, Mitsuokella sp., Actinomyces sp. Oral taxon 848 str. F0332, p- 2534 - 18B5-gut-group are found in NT. Seven common genera within which different species are identified in TT and NT, suggesting differences in bacterial behaviour and characteristics within the same genus. A total of 12 phyla, 35 genera, and 54 species were found to be relatively more abundant in TT compared to NT. Conversely, 7 phyla, 32 genera, and 45 species were relatively more abundant in NT than in TT. Considerable variations in diversity metrics were found between TT and NT.

CONCLUSION

This systematic review is the first to identify a distinct bacteriome exclusive to OSCC tumour tissue compared to normal tissue using 16S ribosomal RNA sequencing. This pioneering work lays the foundation for future studies on the oral microbiome as a potential diagnostic or therapeutic target in oral cancer management. It emphasizes the importance of exploring species-level differences for a deeper understanding of their roles in OSCC.

TRIAL REGISTRATION

Not applicable.

Exploring the role of oral bacteria in oral cancer: a narrative review

A growing body of research indicates that a wide range of cancer types may correlate with human microbiome components. On the other hand, little is known about the potential contribution of the oral microbiota to oral cancer. However, some oral microbiome components can stimulate different tumorigenic processes associated with the development of cancer. In this line, two prevalent oral infections, Porphyromonas gingivalis, and Fusobacterium nucleatum can increase tumor growth. The microbiome can impact the course of the illness through direct interactions with the human body and major modifications to the toxicity and responsiveness to different kinds of cancer therapy. Recent research has demonstrated a relationship between specific phylogenetic groupings and the results of immunotherapy treatment for particular tumor types. Conversely, there has been a recent upsurge in interest in the possibility of using microbes to treat cancer. At the moment, some species, such as Salmonella typhimurium and Clostridium spp., are being explored as possible cancer treatment vectors. Thus, understanding these microbial interactions highlights the importance of maintaining a healthy oral microbiome in preventing oral cancers. From this perspective, this review will discuss the role of the microbiome on oral cancers and their possible application in oral cancer treatment/improvement.

Causal Association Between Microbiome and Oral-Oropharyngeal Cancer: A Mendelian Randomization Study

INTRODUCTION AND AIMS

This study aimed to examine the causal link between oral microbiome and the risk of oral and oropharyngeal squamous cell carcinoma (OOPSCC) using Mendelian randomization (MR).

METHODS

Utilizing single nucleotide polymorphisms as instrumental variables, we applied the MR inverse-variance weighted approach to assess the impact of salivary and tongue microbiome on OOPSCC. The data were obtained from the CNGBdb database and the UK Biobank, and analytical procedures were performed using the R package 'TwoSampleMR'. To ensure the robustness of our findings, we conducted sensitivity studies, which included the MR-Egger intercept test, to establish strong correlations and eliminate the phenomenon of horizontal pleiotropy.

RESULT

Our large-scale MR study revealed a genetically predisposed causal relationship between 13 microbial taxa, each from saliva and tongue, with OOPSCC. Notably, microbial taxa from six genera, including Prevotella, Neisseria, Veillonella, Granulicatella, Treponema, and Streptococcus, in both salivary and tongue microbiomes, showed this relationship. Conversely, several taxa, including Hemophilus, Solobacterium, Campylobacter, and Porphyromonas, predominantly demonstrated an inverse relationship, suggesting a protective effect. The robustness of our findings was further confirmed through sensitivity analyses, providing additional confidence in our results.

CONCLUSION

Our MR study indicates that the oral microbiota has a significant causal impact on the risk of oral and oropharyngeal cancers. The microbial biomarkers we identified, which are linked to OOPSCC, have the potential to uncover the underlying mechanisms and pave the way for new therapeutic approaches for targeted treatment of these malignancies.

Intra-tumoral bacteria in head and neck cancer: holistic integrative insight

Intra-tumoral bacteria are pivotal in the initiation and progression of head and neck squamous cell carcinoma (HNSCC), exerting a significant influence on tumor cell biology, immune responses, and the tumor microenvironment (TME). Different types and distribution of bacteria threaten the balance of metabolism and the immune environment of tumor cells. Taking advantage of this disrupted homeostasis, intra-tumoral bacteria stimulate the secretion of metabolites or influence specific immune cell types to produce inflammatory or chemokines, thereby influencing the anti-tumor immune response while regulating the level of inflammation and immunosuppression within the TME. Some intra-tumoral bacteria are used as diagnostic and prognostic markers in clinical practice. Based on the unique characteristics of bacteria, the use of engineered bacteria and outer membrane vesicles for drug delivery and biological intervention is a promising new therapeutic strategy. The presence of intra-tumoral bacteria also makes chemoradiotherapy tolerable, resulting in a poor treatment effect. However, due to the immune-related complexity of intra-tumoral bacteria, there may be unexpected effects in immunotherapy. In this review the patterns of intra-tumoral bacteria involvement in HNSCC are discussed, elucidating the dual roles, while exploring the relevance to anti-tumor immune responses in the clinical context and the prospects and limitations of the use of bacteria in targeted therapy.

Implications of intratumoral microbiota in tumor metastasis: a special perspective of microorganisms in tumorigenesis and clinical therapeutics

Tumor metastasis is the main cause of therapeutic failure and mortality in cancer patients. The intricate metastastic process is influenced by both the intrinsic properties of tumor cells and extrinsic factors, such as microorganisms. Notably, some microbiota have been discovered to colonize tumor tissues, collectively known as intratumoral microbiota. Intratumoral microbiota can modulate tumor progression through multiple mechanisms, including regulating immune responses, inducing genomic instability and gene mutations, altering metabolic pathways, controlling epigenetic pathways, and disrupting cancer-related signaling pathways. Furthermore, intratumoral microbiota have been shown to directly impact tumor metastasis by regulating cell adhesion, stem cell plasticity and stemness, mechanical stresses and the epithelial-mesenchymal transition. Indirectly, they may affect tumor metastasis by modulating the host immune system and the tumor microenvironment. These recent findings have reshaped our understanding of the relationship between microorganims and the metastatic process. In this review, we comprehensively summarize the existing knowledge on tumor metastasis and elaborate on the properties, origins and carcinogenic mechanisms of intratumoral microbiota. Moreover, we explore the roles of intratumoral microbiota in tumor metastasis and discuss their clinical implications. Ongoing research in this field will establish a solid foundation for novel therapeutic strategies and clinical treatments for various tumors.

Preclinical in vitro models of HNSCC and their role in drug discovery - an emphasis on the cancer microenvironment and microbiota

INTRODUCTION

Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide. Treatment options and patient outcomes have not improved significantly over the past decades, increasing the need for better preclinical models. Holistic approaches that include an intact and functional immune compartment along with the patient's individual tumor microbiome will help improve the predictive value of novel drug efficacy.

AREAS COVERED

In this review, we describe the challenges of modeling the complex and heterogeneous tumor landscape in HNSCC and the importance of sophisticated patient-specific 3D in vitro models to pave the way for clinical trials with novel immunomodulatory drugs. We also discuss the impact of the tumor microbiome and the potential implications for prospective drug screening and validation trials.

EXPERT OPINION

The repertoire of well-characterized preclinical 3D in vitro models continues to grow. With the increasing attention to the complex cellular, immunological, molecular, and spatio-temporal characteristics of tumors, well-designed proof-of-concept studies to test novel drug efficacy are on the verge of providing valuable, practice-changing insights for clinical trials. Bringing together expertise and improving collaboration between clinicians, academics, and regulatory agencies will facilitate the translation of preclinical findings into clinically meaningful outcomes.

The Oral Microbiome and Cancer

There is growing evidence suggesting a strong association between members of the oral microbiota and various types of cancer, including oral cancer, colorectal cancer, esophageal squamous cell carcinoma, and pancreatic cancer. Periodontal diseases closely associated with pathogenic bacteria in the oral cavity have been shown to be correlated with the occurrence and development of cancers. Among the periodontal disease-associated bacteria in the oral cavity, two prominent oral pathogens, Porphyromonas gingivalis and Fusobacterium nucleatum, have been found to promote tumor cell proliferation, invasion, and migration, as well as to inhibit immune cell function, thereby facilitating tumor progression. The presence of other oral pathogenic bacteria, such as Treponema denticola, Tannerella forsythia, Parvimonas micra, and Aggregatibacter actinomycetemcomitans, has also been found to be associated with cancer worsening. Oral commensal bacteria play a crucial role in maintaining the normal oral homeostasis. However, the relationship between oral commensal bacteria and the occurrence and development of cancers remains controversial. Some studies suggest an increase in oral commensal bacteria during tumor development, while others suggest an association of certain commensal bacteria with lower tumor risk. The microbiota can significantly alter responses and toxicity to various forms of cancer treatment through interactions with the human body, thereby influencing disease progression. In this chapter, we provide a concise overview of current understanding of the role of the oral microbiota in cancer.

Correlation of Porphyromonas gingivalis with esophageal squamous cell carcinoma: a systematic review

OBJECTIVES

This study aimed to assess the correlation of Porphyromonas gingivalis (P. gingivalis) with esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

This systematic review evaluated case-control, cohort, and cross-sectional studies published between 1990 and 2024 that compared ESCC patients and healthy controls regarding the presence of P. gingivalis, risk of ESCC development, overall survival rate and prognosis of ESCC, lymph node metastasis, clinical stage of the disease, cancer cell proliferation and migration, efficacy of chemotherapy, invasion depth, and cell differentiation. Searching process was conducted in Web of Science, Scopus, PubMed, and Cochrane Library. The quality of included studies was assessed by the Newcastle Ottawa scale (NOS).

RESULTS

Of 270 articles, 11 underwent a systematic review with NOS scores ranging from 7 to 9. 5 studies found a correlation between P.gingivalis and overall survival rate of ESCC patients (P < 0.05). 5 studies found a significant correlation between P.gingivalis count and the risk of ESCC development (P < 0.05). 2 studies showed a significant correlation between lymph node metastasis and 3 studies showed a significant correlation between clinical TNM stage and P.gingivalis (P < 0.05).

CONCLUSIONS

High P. gingivalis count increases the risk of development of ESCC, lymph node metastasis, progression to stages 3 and 4, proliferation and migration of cancer cells, and depth of invasion, decreases the overall survival rate and prognosis of the disease, and efficacy of chemotherapy, and results in poorer differentiation of cells.

CLINICAL RELEVANCE

According to our findings, dental clinicians and patients should be informed about the significance of oral hygiene and its relationship with ESCC to prevent future life-threatening diseases.

The oral microbial odyssey influencing chronic metabolic disease

INTRODUCTION

Since the oral cavity is the gateway to the gut, oral microbes likely hold the potential to influence metabolic disease by affecting the gut microbiota.

METHOD

A thorough review of literature has been performed to link the alterations in oral microbiota with chronic metabolic disease by influencing the gut microbiota.

RESULT

A strong correlation exists between abnormalities in oral microbiota and several systemic disorders, such as cardiovascular disease, diabetes, and obesity, which likely initially manifest as oral diseases. Ensuring adequate oral hygiene practices and cultivating diverse oral microflora are crucial for the preservation of general well-being. Oral bacteria have the ability to establish and endure in the gastrointestinal tract, leading to the development of prolonged inflammation and activation of the immune system. Oral microbe-associated prophylactic strategies could be beneficial in mitigating metabolic diseases.

CONCLUSION

Oral microbiota can have a profound impact on the gut microbiota and influence the pathogenesis of metabolic diseases.

Effect of Ultrasonic Cleaning Combined with Antibacterial Polypeptide Periodontal Gel on Inflammatory Reaction and Incidence of Adverse Reactions in Patients with Chronic Gingivitis

The purpose of this investigation was to evaluate the efficacy of ultrasonic subgingival curettage in conjunction with antibacterial polypeptide periodontal gel in the management of chronic periodontitis of moderate to severe severity. Methods included dividing 500 hospitalised patients with moderate to severe chronic periodontitis evenly between an observation group and a control group. Subgingival ultrasonic curettage was performed on the placebo group. The non-treatment group received ultrasonic subgingival curettage and a periodontal gel rinse containing polypeptides. Results were compared before and after treatment in terms of the periodontal index, inflammation in the gingival crevicular fluid, and occlusal and masticatory efficiency. Both groups saw significant reductions in occlusal duration and occlusal force balance after treatment compared to pre-treatment levels, though the observation group saw a more dramatic decrease in these indices than the control group with P ≤ 0.05. The treatment and observation groups both saw significant reductions in the masticatory efficiency standard deviation afterward, but the index in the observation group was significantly lower than that of the control group with P ≤ 0.05.The authors claim that moderate to severe chronic periodontitis can be effectively treated with a combination of polypeptide periodontal gel and ultrasonic subgingival curettage. Substantial decreases from pre-treatment levels for both groups, with the Observation Group's index being significantly lower than the Control Group's index (P ≤ 0.05). It is possible that this treatment will help reduce inflammation and improve your periodontal health. Biting strength and occlusion stability can both be improved at the same time to help patients improve their chewing efficiency. Therefore, this method can be used securely in real-world patient care settings.

[Research and Progress on the Association of Porphyromonas gingivalis with Lung Cancer]

Porphyromonas gingivalis is a key pathogenic microorganism that triggers periodontitis. It is closely associated with oral diseases such as chronic periodontitis and recently found to have a significant correlation with the occurrence, progression, and prognosis of cancer. As the leading malignant tumor in terms of both incidence and mortality worldwide, lung cancer has always been a focus and hotspot of research. The causes of lung cancer are complex and involve multiple factors, including smoking, occupational factors, air pollution, ionizing radiation, diet and nutrition, genetic factors, etc. Researchers have also begun to pay attention to the relationship between oral microbiota and overall health, especially the link with lung cancer. The article summarizes the latest advancements in research on Porphyromonas gingivalis in lung cancer, primarily encompassing etiology and pathogenic mechanisms, and explores its potential as a therapeutic target for lung cancer, aiming to provide new insights and directions for lung cancer prevention and treatment strategies.
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Periodontal pathogens and cancer development

Increasing evidence suggests a significant association between periodontal disease and the occurrence of various cancers. The carcinogenic potential of several periodontal pathogens has been substantiated in vitro and in vivo. This review provides a comprehensive overview of the diverse mechanisms employed by different periodontal pathogens in the development of cancer. These mechanisms induce chronic inflammation, inhibit the host's immune system, activate cell invasion and proliferation, possess anti-apoptotic activity, and produce carcinogenic substances. Elucidating these mechanisms might provide new insights for developing novel approaches for tumor prevention, therapeutic purposes, and survival improvement.

Mechanistic Insights on Microbiota-Mediated Development and Progression of Esophageal Cancer

Esophageal cancer (EC) is one of the most common malignant tumors worldwide, and its two major types, esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), present a severe global public health problem with an increasing incidence and mortality. Established risk factors include smoking, alcohol consumption, and dietary habits, but recent research has highlighted the substantial role of oral microbiota in EC pathogenesis. This review explores the intricate relationship between the microbiome and esophageal carcinogenesis, focusing on the following eight significant mechanisms: chronic inflammation, microbial dysbiosis, production of carcinogenic metabolites, direct interaction with epithelial cells, epigenetic modifications, interaction with gastroesophageal reflux disease (GERD), metabolic changes, and angiogenesis. Certain harmful bacteria, such as Porphyromonas gingivalis and Fusobacterium nucleatum, are specifically implicated in sustaining irritation and tumor progression through pathways including NF-κB and NLRP3 inflammasome. Additionally, the review explores how microbial byproducts, including short-chain fatty acids (SCFAs) and reactive oxygen species (ROS), contribute to DNA harm and disease advancement. Furthermore, the impact of reflux on microbiota composition and its role in esophageal carcinogenesis is evaluated. By combining epidemiological data with mechanistic understanding, this review underscores the potential to target the microbiota-immune system interplay for novel therapeutic and diagnostic strategies to prevent and treat esophageal cancer.

Microbiome-Stealth Regulator of Breast Homeostasis and Cancer Metastasis

Cumulative evidence attests to the essential roles of commensal microbes in the physiology of hosts. Although the microbiome has been a major research subject since the time of Luis Pasteur and William Russell over 140 years ago, recent findings that certain intracellular bacteria contribute to the pathophysiology of healthy vs. diseased tissues have brought the field of the microbiome to a new era of investigation. Particularly, in the field of breast cancer research, breast-tumor-resident bacteria are now deemed to be essential players in tumor initiation and progression. This is a resurrection of Russel's bacterial cause of cancer theory, which was in fact abandoned over 100 years ago. This review will introduce some of the recent findings that exemplify the roles of breast-tumor-resident microbes in breast carcinogenesis and metastasis and provide mechanistic explanations for these phenomena. Such information would be able to justify the utility of breast-tumor-resident microbes as biomarkers for disease progression and therapeutic targets.

Oral and Gut Microbiota Dysbiosis Due to Periodontitis: Systemic Implications and Links to Gastrointestinal Cancer: A Narrative Review

Periodontitis can disrupt oral and gut microbiota, leading to dysbiosis that affects overall systemic health. Besides the spread of periodontal pathogens by the hematogenous route, they can also be translocated into the gastrointestinal tract, possibly intervening in the neoplastic process in the gastrointestinal tract. This manuscript reviews the relationship between oral and gut microbiota due to periodontitis, discussing systemic health implications and potential links to gastrointestinal cancer. This article highlights the significance and effect of dysbiosis in the gut, emphasizing the importance of maintaining oral health to prevent systemic diseases. Lastly, it will go through therapeutic innovations such as probiotics and oral microbiota analysis tools for systemic disease detection. These findings will mark the integration of oral health management in clinical practice to lower systemic disease risk and improve overall patient outcomes. Aim of work: This manuscript aims to unravel the pathological interaction between oral and gut microbiota and their bidirectional effect on systemic diseases. Materials and methods: The review was performed using the MEDLINE and ScienceDirect databases. Reviewed articles were published in English between the year 2015 and 2024. The search used keywords such as ("oral microbiota" AND "periodontal disease") OR ("oral microbiota" AND "gastrointestinal cancer") OR ("Porphyromonas gingivalis" AND "periodontal disease") OR ("Helicobacter pylori" AND "gastric cancer") OR ("gut microbiome" AND "inflammatory bowel disease") OR ("oral microbiome" AND "systemic diseases"). Conclusions: The dysbiotic change in the oral cavity due to periodontitis is linked directly and indirectly to systemic diseases such as IBS, neurodegenerative diseases, muscle joint diseases, respiratory infections, and gastrointestinal cancer; this underscores the importance of maintaining oral hygiene for prophylaxis of oral diseases and the prevention of systemic diseases. A better understanding of the interconnections between oral health and systemic diseases will integrate oral health management to offer new prevention, diagnostic, and treatment opportunities to improve overall patient outcomes.

Comprehensive survival analysis of oral squamous cell carcinoma patients undergoing initial radical surgery

OBJECTIVE

This study was designed to evaluate the five-year overall survival (OS) rate and postoperative survival time of patients diagnosed with oral squamous cell carcinoma (OSCC), as well as examine the clinical and pathological factors influencing survival outcomes in OSCC patients.

METHODS

Data were collected from OSCC patients who underwent their first radical surgical intervention in the Department of Maxillofacial Surgery at the First Affiliated Hospital of Chongqing Medical University between April 2014 and December 2016. Follow-up was conducted until March 2022.

RESULTS

The study included a total of 162 patients. The observed 5-year OS rate was 59.3%. Approximately 45.7% of OSCC patients experienced postoperative recurrence or metastasis, with a 5-year overall disease-free survival rate of 49.4%. There was no significant difference in the impact of sex, age, smoking, alcohol consumption, primary tumour location, depth of invasion or primary tumour size on the 5-year survival rate (p > 0.05). Univariate analysis revealed that clinical stage (Hazard Ratio = 2.239, p = 0.004), perineural invasion (PNI) (Hazard Ratio = 1.712, p = 0.03), lymph node metastasis (pN) (Hazard Ratio = 2.119, p = 0.002), pathological differentiation (Hazard Ratio = 2.715, p < 0.001), and recurrence or metastasis (Hazard Ratio = 10.02, p < 0.001) were significant factors influencing survival. Multivariate analysis further indicated that pathological differentiation (Hazard Ratio = 2.291, p = 0.001), PNI (Hazard Ratio = 1.765, p = 0.031) and recurrence or metastasis (Hazard Ratio = 9.256, p < 0.001) were independent risk factors of survival. Intriguingly, 11 OSCC patients were diagnosed with oesophageal squamous cell carcinoma (ESCC) within 1-4 years following surgery.

CONCLUSION

The survival prognosis of OSCC patients is significantly associated with clinical stage, PNI, lymph node metastasis, pathological differentiation, and recurrence or metastasis. Pathological differentiation, PNI and recurrence or metastasis are independent risk factors affecting survival. Routine clinical screening for ESCC may be recommended for OSCC patients with a history of alcohol consumption and tobacco use.

Periodontitis promotes hepatocellular carcinoma in Stelic Animal model (STAM) mice

Periodontitis is a prevalent oral inflammatory disease that leads to alveolar bone loss and may exert an adverse impact on systemic health. Periodontal disease may be associated with hepatocellular carcinoma (HCC); however, the mechanism of such an association is unknown. In this study, Stelic Animal model (STAM) mice, a model of nonalcoholic steatohepatitis (NASH)-HCC, were induced to develop periodontitis and subjected to histopathological and immunological analyses. HCC progression was greater in STAM mice with experimental periodontitis compared with that in STAM mice without experimental periodontitis. Tumor necrosis factor-α (TNFα), matrix metalloproteinase-9 (MMP9), collagen 1, and angiopoietin-like protein 2 (ANGPTL2) gene expression was significantly increased in the liver of the periodontitis group. ANGPTL2 was previously reported to be involved in the pathogenesis of periodontitis, and HCC and ANGPTL2 protein tended to be more abundant in the pocket epithelium of STAM mice with experimental periodontitis than in control STAM mice. ANGPTL2 levels in the serum of STAM mice with experimental periodontitis tended to be higher than in control STAM mice. Our results indicate that ANGPTL2 is produced in chronically inflamed periodontal tissue and then travels to the liver via the bloodstream where it accumulates to promote the progression of hepatocellular carcinoma.

The role of periodontitis in cancer development, with a focus on oral cancers

Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.

Diversity and compositional differences in the oral microbiome of oral squamous cell carcinoma patients and healthy controls: a scoping review

Objectives

The human oral microbiome may play a role in the development of oral squamous cell carcinoma. The aim of this scoping review was to examine microbial diversity and differences in the composition of the oral microbiome between OSCC patients and healthy controls.

Methods

A literature search (in PubMed and Embase.com) was performed on January 9, 2023. The outcome variables used from the included studies of this review were alpha- and beta diversity and oral microbiome composition profiles for each taxonomic level (phylum-, class-, order-, genus- and species level).

Results

Thirteen out of 423 studies were included in this review compromising 1,677 subjects, of which 905 (54.0%) were OSCC patients and 772 (46.0%) were healthy controls. Most studies found a higher alpha diversity in the OSCC patient group and significantly different beta diversities between OSCC patient samples and healthy control samples. Studies reported more abundant Fusobacteria (on phylum level), Fusobacterium (on genus level), Fusobacterium nucleatum, Porphyromonas endodontalis and Prevotella intermedia (on species level) in OSCC patients. The healthy control group had more abundant Actinobacteria (on phylum level), Streptococcus and Veilonella (on genus level) and Veilonella parvula (on species level) according to most studies.

Conclusions

Our findings show differences in oral microbiome diversity and composition in OSCC patients. Clinical implications demand continuing study. Development of internationally accepted standard procedures for oral sample collection and oral microbiota analysis is needed for more conclusive and clinically relevant comparisons in future research.

Complete genome sequences of three Porphyromonas gingivalis strains, isolated from patient with esophageal squamous cell carcinoma and healthy individual in China

Here, we report the complete genome sequences of three Porphyromonas gingivalis, one from patient with esophageal cancer (LyEC01), and the other two from periodontally healthy individuals (LyG-1 and LyG-2) in 2021 and 2023. The genome sizes of LyEC01, LyG-1, and LyG-2 were 2,408,275, 2,411,440, and 2,411,481 bp, respectively.

Structure based High-Throughput Virtual Screening, Molecular Docking and Molecular Dynamics Study of anticancer natural compounds against fimbriae (FimA) protein of Porphyromonas gingivalis in oral squamous cell carcinoma

Oral cancer is among the most common cancer in the world. Tobacco, alcohol, and viruses have been regarded as a well- known risk factors of OCC however, 15% of OSCC cases occurred each year without these known risk factors. Recently a myriad of studies has shown that bacterial infections lead to cancer. Accumulated shreds of evidence have demonstrated the role of Porphyromonas gingivalis (P. gingivalis) in OSCC. The virulence factor FimA of P. gingivalis activates the oncogenic pathways in OSCC by upregulating various cytokines. It also led to the inactivation of a tumor suppressor protein p53. The present Insilico study uses High-Throughput Virtual Screening, molecular docking, and molecular dynamics techniques to find the potential compounds against the target protein FimA. The goal of this study is to identify the anti-cancer lead compounds retrieved from natural sources that can be used to develop potent drug molecules to treat P.gingivalis-related OSCC. The anticancer natural compounds library was screened to identify the potential lead compounds. Furthermore, these lead compounds were subjected to precise docking, and based on the docking score potential lead compounds were identified. The top docked receptor-ligand complex was subjected to molecular dynamics simulation. A study of this insilico finding provides potent lead molecules which help in the development of therapeutic drugs against the target protein FimA in OSCC.

Analysis of Oral and Gut Microbiome Composition and Its Impact in Patients with Oral Squamous Cell Carcinoma

The impact of gut and oral microbiota on the clinical outcomes of patients with oral squamous cell carcinoma (OSCC) is unknown. We compared the bacterial composition of dental plaque and feces between patients with OSCC and healthy controls (HCs). Fecal and dental plaque samples were collected from 7 HCs and 18 patients with OSCC before treatment initiation. Terminal restriction fragment-length polymorphism analysis of 16S rRNA genes was performed. Differences in bacterial diversity between the HC and OSCC groups were examined. We compared the occupancy of each bacterial species in samples taken from patients with OSCC and HCs and analyzed the correlation between PD-L1 expression in the tumor specimens and the occupancy of each bacterial species. The gut and oral microbiota of patients with OSCC were more varied than those of HCs. Porphyromonas and Prevotella were significantly more abundant in patients with OSCC than in HCs. The abundance of Clostridium subcluster XIVa in the gut microbiota of the PD-L1-positive group was significantly greater than that in the PD-L1-negative group. The oral and gut microbiomes of patients with OSCC were in a state of dysbiosis. Our results suggest the possibility of new cancer therapies targeting these disease-specific microbiomes using probiotics and synbiotics.

Porphyromonas gingivalis, a bridge between oral health and immune evasion in gastric cancer

Porphyromonas gingivalis (P. gingivalis) is a gram-negative oral pathogen associated with chronic periodontitis. Previous studies have linked poor oral health and periodontitis with oral cancer. Severe cases of periodontal disease can result in advanced periodontitis, leading to tissue degradation, tooth loss, and may also correlate with higher gastric cancer (GC) risk. In fact, tooth loss is associated with an elevated risk of cancer. However, the clinical evidence for this association remains inconclusive. Periodontitis is also characterized by chronic inflammation and upregulation of members of the Programmed Death 1/PD1 Ligand 1 (PD1/PDL1) axis that leads to an immunosuppressive state. Given that chronic inflammation and immunosuppression are conditions that facilitate cancer progression and carcinogenesis, we hypothesize that oral P. gingivalis and/or its virulence factors serve as a mechanistic link between oral health and gastric carcinogenesis/GC progression. We also discuss the potential impact of P. gingivalis' virulence factors (gingipains, lipopolysaccharide (LPS), and fimbriae) on inflammation and the response to immune checkpoint inhibitors in GC which are part of the current standard of care for advanced stage patients.

Porphyromonas gingivalis suppresses oral squamous cell carcinoma progression by inhibiting MUC1 expression and remodeling the tumor microenvironment

Bacteria are the causative agents of various infectious diseases; however, the anti-tumor effect of some bacterial species has attracted the attention of many scientists. The human oral cavity is inhabited by abundant and diverse bacterial communities and some of these bacterial communities could play a role in tumor suppression. Therefore, it is crucial to find oral bacterial species that show anti-tumor activity on oral cancers. In the present study, we found that a high abundance of Porphyromonas gingivalis, an anaerobic periodontal pathogen, in the tumor microenvironment (TME) was positively associated with the longer survival of patients with oral squamous cell carcinoma (OSCC). An in vitro assay confirmed that P. gingivalis accelerated the death of OSCC cells by inducing cell cycle arrest at the G2/M phase, thus exerting its anti-tumor effect. We also found that P. gingivalis significantly decreased tumor growth in a 4-nitroquinoline-1-oxide-induced in situ OSCC mouse model. The transcriptomics data demonstrated that P. gingivalis suppressed the biosynthesis of mucin O-glycan and other O-glycans, as well as the expression of chemokines. Validation experiments further confirmed the downregulation of mucin-1 (MUC1) and C-X-C motif chemokine 17 (CXCL17) expression by P. gingivalis treatment. Flow cytometry analysis showed that P. gingivalis successfully reversed the immunosuppressive TME, thereby suppressing OSCC growth. In summary, the findings of the present study indicated that the rational use of P. gingivalis could serve as a promising therapeutic strategy for OSCC.

Antimicrobial efficacy of antiplaque agents of common toothpastes against Porphyromonas gingivalis and Streptococcus oralis: An in vitro study

Background

This study was designed to evaluate the antimicrobial activity of common gum protection and antiplaque toothpastes against Porphyromonas gingivalis (P. gingivalis) and Streptococcus oralis (S. oralis) as important periodontal pathogens.

Materials and Methods

This experimental study investigated the antimicrobial activity of 15 commonly used toothpastes from different companies on the two common types of periopathogens, S. oralis and P. gingivalis . The antimicrobial activity of toothpaste was evaluated at three concentrations of 100%, 50%, and 25% and analyzed by agar well diffusion plate method and zone of inhibition. The obtained data were compared and statistically analyzed by SPSS software using one-way ANOVA and the least significant difference post hoc tests (α = 0.05).

Results

One-way ANOVA showed that the mean diameter of the two-bacterial zone of inhibition was significantly different at 100%, 50%, and 25% concentrations of toothpastes (P < 0.001). In general, the mean diameter of the zone of inhibition was greater at 100% concentration than the other two concentrations in all toothpastes. The highest zone of inhibition of the S. oralis was in the toothpastes containing tin. Further, the highest zone of inhibition of P. gingivalis was found in the triclosan-containing toothpastes.

Conclusion

Toothpastes containing triclosan had the most antimicrobial activity against P. gingivalis . Moreover, toothpastes containing tin compounds had the most antimicrobial effect against S. oralis .

A pleiotropic role of sialidase in the pathogenicity of Porphyromonas gingivalis

As one of the keystone pathogens of periodontitis, the oral bacterium Porphyromonas gingivalis produces an array of virulence factors, including a recently identified sialidase (PG0352). Our previous report involving loss-of-function studies indicated that PG0352 plays an important role in the pathophysiology of P. gingivalis. However, this report had not been corroborated by gain-of-function studies or substantiated in different P. gingivalis strains. To fill these gaps, herein we first confirm the role of PG0352 in cell surface structures (e.g., capsule) and serum resistance using P. gingivalis W83 strain through genetic complementation and then recapitulate these studies using P. gingivalis ATCC33277 strain. We further investigate the role of PG0352 and its counterpart (PGN1608) in ATCC33277 in cell growth, biofilm formation, neutrophil killing, cell invasion, and P. gingivalis-induced inflammation. Our results indicate that PG0352 and PGN1608 are implicated in P. gingivalis cell surface structures, hydrophobicity, biofilm formation, resistance to complement and neutrophil killing, and host immune responses. Possible molecular mechanisms involved are also discussed. In summary, this report underscores the importance of sialidases in the pathophysiology of P. gingivalis and opens an avenue to elucidate their underlying molecular mechanisms.

Oral microbiota and oral squamous cell carcinoma: a review of their relation and carcinogenic mechanisms

Oral Squamous Cell Carcinoma (OSCC) is the most common type of head and neck cancer worldwide. Emerging research suggests a strong association between OSCC and the oral microbiota, a diverse community of bacteria, fungi, viruses, and archaea. Pathogenic bacteria, in particular Porphyromonas gingivalis and Fusobacterium nucleatum, have been closely linked to OSCC. Moreover, certain oral fungi, such as Candida albicans, and viruses, like the human papillomavirus, have also been implicated in OSCC. Despite these findings, the precise mechanisms through which the oral microbiota influences OSCC development remain unclear and necessitate further research. This paper provides a comprehensive overview of the oral microbiota and its relationship with OSCC and discusses potential carcinogenic pathways that the oral microbiota may activate or modulate are also discussed.

The Roles and Interactions of Porphyromonas gingivalis and Fusobacterium nucleatum in Oral and Gastrointestinal Carcinogenesis: A Narrative Review

Epidemiological studies have spotlighted the intricate relationship between individual oral bacteria and tumor occurrence. Porphyromonas gingivalis and Fusobacteria nucleatum, which are known periodontal pathogens, have emerged as extensively studied participants with potential pathogenic abilities in carcinogenesis. However, the complex dynamics arising from interactions between these two pathogens were less addressed. This narrative review aims to summarize the current knowledge on the prevalence and mechanism implications of P. gingivalis and F. nucleatum in the carcinogenesis of oral squamous cell carcinoma (OSCC), colorectal cancer (CRC), and pancreatic ductal adenocarcinoma (PDAC). In particular, it explores the clinical and experimental evidence on the interplay between P. gingivalis and F. nucleatum in affecting oral and gastrointestinal carcinogenesis. P. gingivalis and F. nucleatum, which are recognized as keystone or bridging bacteria, were identified in multiple clinical studies simultaneously. The prevalence of both bacteria species correlated with cancer development progression, emphasizing the potential impact of the collaboration. Regrettably, there was insufficient experimental evidence to demonstrate the synergistic function. We further propose a hypothesis to elucidate the underlying mechanisms, offering a promising avenue for future research in this dynamic and evolving field.

Intratumoural microbiota: a new frontier in cancer development and therapy

Human microorganisms, including bacteria, fungi, and viruses, play key roles in several physiological and pathological processes. Some studies discovered that tumour tissues once considered sterile actually host a variety of microorganisms, which have been confirmed to be closely related to oncogenesis. The concept of intratumoural microbiota was subsequently proposed. Microbiota could colonise tumour tissues through mucosal destruction, adjacent tissue migration, and hematogenic invasion and affect the biological behaviour of tumours as an important part of the tumour microenvironment. Mechanistic studies have demonstrated that intratumoural microbiota potentially promote the initiation and progression of tumours by inducing genomic instability and mutations, affecting epigenetic modifications, promoting inflammation response, avoiding immune destruction, regulating metabolism, and activating invasion and metastasis. Since more comprehensive and profound insights about intratumoral microbiota are continuously emerging, new methods for the early diagnosis and prognostic assessment of cancer patients have been under examination. In addition, interventions based on intratumoural microbiota show great potential to open a new chapter in antitumour therapy, especially immunotherapy, although there are some inevitable challenges. Here, we aim to provide an extensive review of the concept, development history, potential sources, heterogeneity, and carcinogenic mechanisms of intratumoural microorganisms, explore the potential role of microorganisms in tumour prognosis, and discuss current antitumour treatment regimens that target intratumoural microorganisms and the research prospects and limitations in this field.

Microbiome in Cancer Development and Treatment

Targeting the microbiome, microbiota-derived metabolites, and related pathways represents a significant challenge in oncology. Microbiome analyses have confirmed the negative impact of cancer treatment on gut homeostasis, resulting in acute dysbiosis and severe complications, including massive inflammatory immune response, mucosal barrier disruption, and bacterial translocation across the gut epithelium. Moreover, recent studies revealed the relationship between an imbalance in the gut microbiome and treatment-related toxicity. In this review, we provide current insights into the role of the microbiome in tumor development and the impact of gut and tumor microbiomes on chemo- and immunotherapy efficacy, as well as treatment-induced late effects, including cognitive impairment and cardiotoxicity. As discussed, microbiota modulation via probiotic supplementation and fecal microbiota transplantation represents a new trend in cancer patient care, aiming to increase bacterial diversity, alleviate acute and long-term treatment-induced toxicity, and improve the response to various treatment modalities. However, a more detailed understanding of the complex relationship between the microbiome and host can significantly contribute to integrating a microbiome-based approach into clinical practice. Determination of causal correlations might lead to the identification of clinically relevant diagnostic and prognostic microbial biomarkers. Notably, restoration of intestinal homeostasis could contribute to optimizing treatment efficacy and improving cancer patient outcomes.

The impacts of oral and gut microbiota on alveolar bone loss in periodontitis

Periodontitis, a chronic infectious disease, primarily arises from infections and the invasion of periodontal pathogens. This condition is typified by alveolar bone loss resulting from host immune responses and inflammatory reactions. Periodontal pathogens trigger aberrant inflammatory reactions within periodontal tissues, thereby exacerbating the progression of periodontitis. Simultaneously, these pathogens and metabolites stimulate osteoclast differentiation, which leads to alveolar bone resorption. Moreover, a range of systemic diseases, including diabetes, postmenopausal osteoporosis, obesity and inflammatory bowel disease, can contribute to the development and progression of periodontitis. Many studies have underscored the pivotal role of gut microbiota in bone health through the gut-alveolar bone axis. The circulation may facilitate the transfer of gut pathogens or metabolites to distant alveolar bone, which in turn regulates bone homeostasis. Additionally, gut pathogens can elicit gut immune responses and direct immune cells to remote organs, potentially exacerbating periodontitis. This review summarizes the influence of oral microbiota on the development of periodontitis as well as the association between gut microbiota and periodontitis. By uncovering potential mechanisms of the gut-bone axis, this analysis provides novel insights for the targeted treatment of pathogenic bacteria in periodontitis.

Oral Pathogenic Bacteria and the Oral-Gut-Liver Axis: A New Understanding of Chronic Liver Diseases

Liver diseases have long been a prevalent cause of morbidity and mortality, and their development and progression involve multiple vital organs throughout the body. Recent studies on the oral-gut-liver axis have revealed that the oral microbiota is associated with the pathophysiology of chronic liver diseases. Since interventions aimed at regulating oral biological disorders may delay the progress of liver disease, it is crucial to better comprehend this process. Oral bacteria with potential pathogenicity have been extensively studied and are closely related to several types of chronic liver diseases. Therefore, this review will systemically describe the emerging role of oral pathogenic bacteria in common liver diseases, including alcoholic liver disease (ALD), non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver disease (NAFLD), cirrhosis, autoimmune liver diseases (AILD), and liver cancer, and bring in new perspectives for future research.

Subtype-Based Microbial Analysis in Non-small Cell Lung Cancer

BACKGROUND

The human lung serves as a niche for a unique and dynamic bacterial community related to the development and aggravation of multiple respiratory diseases. Therefore, identifying the microbiome status is crucial to maintaining the microecological balance and maximizing the therapeutic effect on lung diseases. Therefore, we investigated the histological type-based differences in the lung microbiomes of patients with lung cancer.

METHODS

We performed 16S rRNA sequencing to evaluate the respiratory tract microbiome present in bronchoalveolar lavage fluid. Patients with non-small cell lung cancer were stratified based on two main subtypes of lung cancer: adenocarcinoma and squamous cell carcinoma (SqCC).

RESULTS

Among the 84 patients analyzed, 64 (76.2%) had adenocarcinoma, and 20 (23.8%) had SqCC. The α- and β-diversities showed significant differences between the two groups (p=0.004 for Chao1, p=0.001 for Simpson index, and p=0.011 for PERMANOVA). Actinomyces graevenitzii was dominant in the SqCC group (linear discriminant analysis [LDA] score, 2.46); the populations of Haemophilus parainfluenza (LDA score, 4.08), Neisseria subflava (LDA score, 4.07), Porphyromonas endodontalis (LDA score, 3.88), and Fusobacterium nucleatum (LDA score, 3.72) were significantly higher in the adenocarcinoma group.

CONCLUSION

Microbiome diversity is crucial for maintaining homeostasis in the lung environment, and dysbiosis may be related to the development and prognosis of lung cancer. The mortality rate was high, and the microbiome was not diverse in SqCC. Further large-scale studies are required to investigate the role of the microbiome in the development of different lung cancer types.

The Gum-Gut Axis: Periodontitis and the Risk of Gastrointestinal Cancers

Periodontitis has been linked to an increased risk of various chronic non-communicable diseases, including gastrointestinal cancers. Indeed, dysbiosis of the oral microbiome and immune-inflammatory pathways related to periodontitis may impact the pathophysiology of the gastrointestinal tract and its accessory organs through the so-called "gum-gut axis". In addition to the hematogenous spread of periodontal pathogens and inflammatory cytokines, recent research suggests that oral pathobionts may translocate to the gastrointestinal tract through saliva, possibly impacting neoplastic processes in the gastrointestinal, liver, and pancreatic systems. The exact mechanisms by which oral pathogens contribute to the development of digestive tract cancers are not fully understood but may involve dysbiosis of the gut microbiome, chronic inflammation, and immune modulation/evasion, mainly through the interaction with T-helper and monocytic cells. Specifically, keystone periodontal pathogens, including Porphyromonas gingivalis and Fusobacterium nucleatum, are known to interact with the molecular hallmarks of gastrointestinal cancers, inducing genomic mutations, and promote a permissive immune microenvironment by impairing anti-tumor checkpoints. The evidence gathered here suggests a possible role of periodontitis and oral dysbiosis in the carcinogenesis of the enteral tract. The "gum-gut axis" may therefore represent a promising target for the development of strategies for the prevention and treatment of gastrointestinal cancers.

Specific Oral Microbial Differences in Proteobacteria and Bacteroidetes Are Associated with Distinct Sites When Moving from Healthy Mucosa to Oral Dysplasia-A Microbiome and Gene Profiling Study and Focused Review

Oral potentially malignant disorders (OPMDs) are a group of conditions that carry a risk of oral squamous cell carcinoma (OSCC) development. Recent studies indicate that periodontal disease-associated pathogenic bacteria may play a role in the transition from healthy mucosa to dysplasia and to OSCC. Yet, the microbial signatures associated with the transition from healthy mucosa to dysplasia have not been established. To characterize oral microbial signatures at these different sites, we performed a 16S sequencing analysis of both oral swab and formalin-fixed, paraffin-embedded tissue (FFPE) samples. We collected oral swabs from healthy mucosa (from healthy patients), histologically normal mucosa adjacent to dysplasia, and low-grade oral dysplasia. Additionally, FFPE samples from histologically normal mucosa adjacent to OSCC, plus low grade and high-grade oral dysplasia samples were also collected. The collected data demonstrate significant differences in the alpha and beta microbial diversities of different sites in oral mucosa, dysplasia, and OSCC, as well as increased dissimilarities within these sites. We found that the Proteobacteria phyla abundance increased, concurrent with a progressive decrease in the Firmicutes phyla abundance, as well as altered levels of Enterococcus cecorum, Fusobacterium periodonticum, Prevotella melaninogenica, and Fusobacterium canifelinum when moving from healthy to diseased sites. Moreover, the swab sample analysis indicates that the oral microbiome may be altered in areas that are histologically normal, including in mucosa adjacent to dysplasia. Furthermore, trends in specific microbiome changes in oral swab samples preceded those in the tissues, signifying early detection opportunities for clinical diagnosis. In addition, we evaluated the gene expression profile of OSCC cells (HSC-3) infected with either P. gingivalis, T. denticola, F. nucelatum, or S. sanguinis and found that the three periodontopathogens enrich genetic processes related to cancer progression, including skin keratinization/cornification, while the commensal enriched processes related to RNA processing and adhesion. Finally, we reviewed the dysplasia microbiome literature and found a significant decrease in commensal bacteria, such as the Streptococci genus, and a simultaneous increase in pathogenic bacteria, mainly Bacteroidetes phyla and Fusobacterium genus. These findings suggest that features of the oral microbiome can serve as novel biomarkers for dysplasia and OSCC disease progression.

Salivary microbiome profiles of oral cancer patients analyzed before and after treatment

BACKGROUND

Treating oral squamous cell carcinoma (OSCC) introduces new ecological environments in the oral cavity. This is expected to cause changes in the oral microbiome. The purpose of this study was to gain new information on the salivary microbiome of OSCC patients in order to improve the aftercare of OSCC patients. The aims of this study were to investigate possible changes in the salivary microbiome profiles of OSCC patients before and after cancer treatment and to compare these changes with the profiles of healthy controls.

PATIENTS AND METHODS

Paraffin-stimulated whole saliva samples were collected, and the salivary flow rate was measured from 99 OSCC patients prior to surgical resection of the tumor and other adjuvant therapy. After treatment, 28 OSCC patients were re-examined with a mean follow-up time of 48 months. In addition, 101 healthy controls were examined and sampled. After DNA extraction and purification, the V4 hypervariable region of the 16S rRNA gene was amplified and sequenced using Illumina MiSeq. The merged read pairs were denoised using UNOISE3, mapped to zero-radius operational taxonomic units (zOTUs), and the representative zOTU sequences were assigned a taxonomy using HOMD. Descriptive statistics were used to study the differences in the microbial profiles of OSCC patients before and after treatment and in comparison to healthy controls.

RESULTS

At baseline, the OSCC patients showed a higher relative abundance of zOTUs classified as Streptococcus anginosus, Abiotrophia defectiva, and Fusobacterium nucleatum. The microbial profiles differed significantly between OSCC patients and healthy controls (F = 5.9, p < 0.001). Alpha diversity of the salivary microbiome of OSCC patients was decreased at the follow-up, and the microbial profiles differed significantly from the pre-treatment (p < 0.001) and from that of healthy controls (p < 0.001).

CONCLUSIONS

OSCC patients' salivary microbiome profile had a higher abundance of potentially pathogenic bacteria compared to healthy controls. Treatment of the OSCC caused a significant decrease in alpha diversity and increase in variability of the salivary microbiome, which was still evident after several years of follow-up. OSCC patients may benefit from preventive measures, such as the use of pre- or probiotics, salivary substitutes, or dietary counseling. Video Abstract.

Oral microbiome: a doubtful predictor but potential target of cardiovascular diseases

Our oral cavity houses various types of microbes including bacteria, protozoa, fungi and viruses, harboring over 700 bacterial species. Oral dysbiosis refers to the imbalance between symbionts and pathobionts in the oral cavity, posing potential threats to host cardiovascular health. Importantly, oral dysbiosis promotes cardiovascular pathophysiology through different mechanisms. Although overgrowth of certain pathogenic bacteria have been indicated in some cardiometabolic diseases, it is still premature to consider oral microbiome as a suitable predictor for non-invasive diagnostic purpose. However, targeting oral microbiome might still provide preventive and therapeutic insights on cardiovascular diseases. Further extensive efforts are needed to deepen our understanding on oral-cardiovascular connection in the context of diagnostic and therapeutic perspectives.

Periodontal Health and Disease in the Context of Systemic Diseases

During recent years, considerable progress has been made in understanding the etiopathogenesis of periodontitis in its various forms and their interactions with the host. Furthermore, a number of reports have highlighted the importance of oral health and disease in systemic conditions, especially cardiovascular diseases and diabetes. In this regard, research has attempted to explain the role of periodontitis in promoting alteration in distant sites and organs. Recently, DNA sequencing studies have revealed how oral infections can occur in distant sites such as the colon, reproductive tissues, metabolic diseases, and atheromas. The objective of this review is to describe and update the emerging evidence and knowledge regarding the association between periodontitis and systemic disease and to analyse the evidence that has reported periodontitis as a risk factor for the development of various forms of systemic diseases in order to provide a better understanding of the possible shared etiopathogenetic pathways between periodontitis and the different forms of systemic diseases.

Molecular insights into the role of electronic cigarettes in oral carcinogenesis

Electronic cigarette (EC) usage or vaping has seen a significant rise in recent years across various parts of the world. They have been publicized as a safe alternative to smoking; however, this is not supported strongly by robust research evidence. Toxicological analysis of EC liquid and aerosol has revealed presence of several toxicants with known carcinogenicity. Oral cavity is the primary site of exposure of both cigarette smoke and EC aerosol. Role of EC in oral cancer is not as well-researched as that of traditional smoking. However, several recent studies have shown that it can lead to a wide range of potentially carcinogenic molecular events in oral cells. This review delineates the oral carcinogenesis potential of ECs at the molecular level, providing a summary of the effects of EC usage on cancer therapy resistance, cancer stem cells (CSCs), immune evasion, and microbiome dysbiosis, all of which may lead to increased tumor malignancy and poorer patient prognosis. This review of literature indicates that ECs may not be as safe as they are perceived to be, however further research is needed to definitively determine their oncogenic potential.

Insights into oral microbiome and colorectal cancer - on the way of searching new perspectives

Microbiome is a keystone polymicrobial community that coexist with human body in a beneficial relationship. These microorganisms enable the human body to maintain homeostasis and take part in mechanisms of defense against infection and in the absorption of nutrients. Even though microbiome is involved in physiologic processes that are beneficial to host health, it may also cause serious detrimental issues. Additionally, it has been proven that bacteria can migrate to other human body compartments and colonize them even although significant structural differences with the area of origin exist. Such migrations have been clearly observed when the causes of genesis and progression of colorectal cancer (CRC) have been investigated. It has been demonstrated that the oral microbiome is capable of penetrating into the large intestine and cause impairments leading to dysbiosis and stimulation of cancerogenic processes. The main actors of such events seem to be oral pathogenic bacteria belonging to the red and orange complex (regarding classification of bacteria in the context of periodontal diseases), such as Porphyromonas gingivalis and Fusobacterium nucleatum respectively, which are characterized by significant amount of cancerogenic virulence factors. Further examination of oral microbiome and its impact on CRC may be crucial on early detection of this disease and would allow its use as a precise non-invasive biomarker.

Human microbiomes in cancer development and therapy

Colonies formed by bacteria, archaea, fungi, and viral groups and their genomes, metabolites, and expressed proteins constitute complex human microbiomes. An increasing evidences showed that carcinogenesis and disease progression were link to microbiomes. Different organ sources, their microbial species, and their metabolites are different; the mechanisms of carcinogenic or procancerous are also different. Here, we summarize how microbiomes contribute to carcinogenesis and disease progression in cancers of the skin, mouth, esophagus, lung, gastrointestinal, genital, blood, and lymph malignancy. We also insight into the molecular mechanisms of triggering, promoting, or inhibiting carcinogenesis and disease progress induced by microbiomes or/and their secretions of bioactive metabolites. And then, the strategies of application of microorganisms in cancer treatment were discussed in detail. However, the mechanisms by which human microbiomes function are still poorly understood. The bidirectional interactions between microbiotas and endocrine systems need to be clarified. Probiotics and prebiotics are believed to benefit human health via a variety of mechanisms, in particular, in tumor inhibition. It is largely unknown how microbial agents cause cancer or how cancer progresses. We expect this review may open new perspectives on possible therapeutic approaches of patients with cancer.

Retrospective analysis of Porphyromonas gingivalis in patients with nasopharyngeal carcinoma in central China

Little is known about the presence and possible role of Porphyromonas gingivalis (P. gingivalis) in nasopharyngeal carcinoma (NPC), its co-infection with Epstein-Barr virus (EBV), or their association with clinical characteristics of patients with NPC in Central China, where NPC is non-endemic. A total of 45 NPC formalin-fixed paraffin-embedded (FFPE) tissues were retrospectively analyzed using immunohistochemistry (IHC) and a nested PCR combined with DNA sequencing to detect the presence of P. gingivalis, and using reverse transcription-quantitative PCR to detect the presence of EBV. Clinical data including EBV and P. gingivalis status were associated with overall survival (OS). All tumors were undifferentiated, non-keratinizing carcinomas, of which 40/45 (88.9%) were positive for EBV (EBV⁺), 26/45 (57.8%) were positive for P. gingivalis (by IHC), and 7/45 (15.6%) were positive for P. gingivalis DNA (P. gingivalis ⁺). All seven P. gingivalis DNA-positive NPCs were co-infected with EBV. The 5-year survival rates of the patients with EBV^-/P. gingivalis ^-, EBV⁺/P. gingivalis ^-, and EBV⁺/P. gingivalis ⁺ tumors were 60.0% (3/5), 39.4% (13/33) and 42.9% (3/7), respectively. No significant difference was found between the OS of NPC patients among the different infection groups (P=0.793). In conclusion, to the best of our knowledge, this is the first study to describe and confirm the presence of P. gingivalis in FFPE tissues from patients with NPC. P. gingivalis was found to co-exist with EBV in NPC tumor tissues, but is not etiologically relevant to NPC in non-endemic areas, such as Central China.

Relationship between pathogenic microorganisms and the occurrence of esophageal carcinoma based on pathological type: a narrative review

INTRODUCTION

Esophageal cancer (EC) is one of the most common malignant tumors of the upper gastrointestinal tract. The etiology of EC is complicated and increasing evidence has shown that microbial infection is closely related to the occurrence of various malignant tumors. Though many studies have been focused on this subject in recent years, the exact relationship between microbial infection and the occurrence of EC remains unclear.

AREAS COVERED

In this review, we searched all eligible literature reports, summarized the most recent studies in this research field, and analyzed the pathogenic microorganisms associated with EC, providing the latest evidence and references for the prevention of pathogenic microorganism-related EC.

EXPERT OPINION

In recent years, increasing evidence has shown that pathogenic microbial infections are closely associated with the development of EC. Therefore, it is necessary to describe in detail the relationship between microbial infection and EC and clarify its possible pathogenic mechanism, which will shed a light on clinical prevention and treatment of cancer caused by pathogenic microbial infection.

Association of Prevotella intermedia with oropharyngeal cancer: A patient-control study

Objective

To investigate the frequencies and bacterial load of three species of periodontal bacteria in samples from oropharyngeal cancer patients versus healthy individuals.

Study design

This is a case-control study based on biopsies collected from tumor tissues obtained from patients with oropharyngeal squamous cell carcinoma between 2016 and 2017 and shed oral mucosal epithelial cells that were collected from controls using the Cepimax® brush, carrying out several brushings towards the posterior third edge of the tongue and the cheek. Porphyromonas gingivalis, Tannerella forsythia and Prevotella intermedia detection and absolute quantification was determined through q-PCR. Statistical analysis included a U- test, X ² , Fisher's exact test, odds ratio (OR) and Conditional logistic regression analysis and unconditional regression analysis (p < 0.05).

Results

A total of 48 donors older than 55 years old participated in this study. The population was distributed into 24 patients (cases) and 24 controls. A robust association was established in cases and controls with significance regarding Prevotella intermedia (OR: 15.00) and Porphyromonas gingivalis (OR:11.00). In the comparison between the amount of each bacteria in the groups, P. intermedia showed a higher bacterial load in oropharyngeal cancer patients (p = 0.04). However, multivariate analysis adjusted to the presence of different bacteria and the diverse confounding variables did not reveal significant differences for oropharyngeal cancer association.

Conclusion

P. gingivalis and P. intermedia were detected more frequently in the group of patients with cancer. The bivariate analysis of the bacterial load evidenced significant differences for Prevotella intermedia, suggesting that it could be associated with oropharyngeal cancer.

Unlocking Modifiable Risk Factors for Alzheimer's Disease: Does the Oral Microbiome Hold Some of the Keys?

Advancing age is recognized as the primary risk factor for Alzheimer's disease (AD); however approximately one third of dementia cases are attributable to modifiable risk factors such as hypertension, diabetes, smoking, and obesity. Recent research also implicates oral health and the oral microbiome in AD risk and pathophysiology. The oral microbiome contributes to the cerebrovascular and neurodegenerative pathology of AD via the inflammatory, vascular, neurotoxic, and oxidative stress pathways of known modifiable risk factors. This review proposes a conceptual framework that integrates the emerging evidence regarding the oral microbiome with established modifiable risk factors. There are numerous mechanisms by which the oral microbiome may interact with AD pathophysiology. Microbiota have immunomodulatory functions, including the activation of systemic pro-inflammatory cytokines. This inflammation can affect the integrity of the blood-brain barrier, which in turn modulates translocation of bacteria and their metabolites to brain parenchyma. Amyloid-β is an antimicrobial peptide, a feature which may in part explain its accumulation. There are microbial interactions with cardiovascular health, glucose tolerance, physical activity, and sleep, suggesting that these modifiable lifestyle risk factors of dementia may have microbial contributors. There is mounting evidence to suggest the relevance of oral health practices and the microbiome to AD. The conceptual framework presented here additionally demonstrates the potential for the oral microbiome to comprise a mechanistic intermediary between some lifestyle risk factors and AD pathophysiology. Future clinical studies may identify specific oral microbial targets and the optimum oral health practices to reduce dementia risk.

In-silico structural characterization and phylogenetic analysis of Nucleoside diphosphate kinase: A novel antiapoptotic protein of Porphyromonas gingivalis

The Nucleoside diphosphate kinase (NDK) protein of Porphyromonas gingivalis (P. gingivalis) plays a crucial role in immune evasion and inhibition of apoptosis in host cells and has the potential to cause cancer. However, its structure has not yet been characterized. We used an in-silico approach to determine the 3D structure of the P. gingivalis NDK. Furthermore, structural characterization and functional annotation were performed using computational approaches. The 3D structure of NDK was predicted through homology modeling. The structural domains predicted for the model protein belong to the NDK family. Structural alignment of prokaryotic and eukaryotic NDKs with the model protein revealed the conservation of the domain region. Structure-based phylogenetic analysis depicted a significant evolutionary relationship between the model protein and the prokaryotic NDK. Functional annotation of the model confirmed structural homology, exhibiting similar enzymatic functions as NDK, including ATP binding and nucleoside diphosphate kinase activity. Furthermore, molecular dynamic (MD) simulation technique stabilized the model structure and provides a thermo-stable protein structure that can be used as a therapeutic target for further studies.

The Contribution of the Human Oral Microbiome to Oral Disease: A Review

The oral microbiome is an emerging field that has been a topic of discussion since the development of next generation sequencing and the implementation of the human microbiome project. This article reviews the current literature surrounding the oral microbiome, briefly highlighting most recent methods of microbiome characterization including cutting edge omics, databases for the microbiome, and areas with current gaps in knowledge. This article also describes reports on microorganisms contained in the oral microbiome which include viruses, archaea, fungi, and bacteria, and provides an in-depth analysis of their significant roles in tissue homeostasis. Finally, we detail key bacteria involved in oral disease, including oral cancer, and the current research surrounding their role in stimulation of inflammatory cytokines, the role of gingival crevicular fluid in periodontal disease, the creation of a network of interactions between microorganisms, the influence of the planktonic microbiome and cospecies biofilms, and the implications of antibiotic resistance. This paper provides a comprehensive literature analysis while also identifying gaps in knowledge to enable future studies to be conducted.

Could there be an interplay between periodontal changes and pancreatic malignancies?

The term "periodontal disease" refers to a group of chronic inflammatory illnesses caused by specific microorganisms from subgingival biofilm, that affect the tooth-supporting tissues. Recent research has also shown that periodontal infection plays a role in aggravating systemic disease states at distal sites, reinforcing the significance of the oral cavity for general health. Additionally, it has been suggested that gastroenterological malignancies may be promoted by hematogenous, enteral or lymphatic translocation of periopathogens. In the past 25 years, the global burden of pancreatic cancer (PC) has more than doubled, making it one of the major causes of cancer-related mortality. Periodontitis has been linked to at least 50% increased risk of PC and it could be considered a risk factor for this malignancy. A recent study performed on 59000 African American women with a follow up of 21 years showed that participants who had poor dental health had higher chances of PC. The findings, according to researchers, might be related to the inflammation that some oral bacteria trigger. Regarding the mortality of PC, periodontitis considerably raises the chance of dying from PC. Microbiome alterations in the gut, oral cavity and pancreatic tissues of PC patients occur when compared to healthy flora, demonstrating a link between PC and microecology. Inflammation may also contribute to PC development, although the underlying pathway is not yet known. The function of the microbiome in PC risk has drawn more focus over the last decade. Future risk of PC has been linked to the oral microbiome, specifically increased levels of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and decreased relative abundance of Leptotrichia and Fusobacteria, suggesting that it may have an impact on the inflammatory condition by expanding, altering, and regulating the commensal microbiome. Patients who received periodontal treatment had significantly decreased incidence rate ratios for PC. By analyzing patterns in the microbiome composition throughout PC development and establishing strategies to enhance the cancer-associated microbial system, we can increase the efficacy of therapy and eventually find an application for the microbial system. The development of immunogenomics and gut micro-genomics in the life sciences will result in a significant advancement in our understanding of how microbial systems and immunotherapy interact, and it may also have intriguing therapeutic implications for extending the lifetime of PC patients.

Bacteria derived extracellular vesicles in the pathogenesis and treatment of gastrointestinal tumours

Extracellular vesicles are fundamentally significant in the communication between cells. Outer Membrane Vesicles(OMVs) are a special kind of EVs produced by Gram-negative bacteria, which are minute exosome-like particles budding from the outer membrane, which have been found to play essential roles in diverse bacterial life events, including regulation of microbial interactions, pathogenesis promotion, stress responses and biofilm formation. Recently, and more researches have explored the substantial potentials of EVs as natural functional nanoparticles in the bioengineering applications in infectious diseases, cardiovascular diseases, autoimmune diseases and neurological diseases, such as antibacterial therapy, cancer drugs and immunoadjuvants, with several candidates in clinical trials showing promising efficacy. However, due to the poor understanding of sources, membrane structures and biogenesis mechanisms of EVs, progress in clinical applications still remains timid. In this review, we summarize the latest findings of EVs, especially in gastrointestinal tract tumours, to provide a comprehensive introduction of EVs in tumorigenesis and therapeutics.