Possible involvement of Enterococcus infection in the pathogenesis of chronic pancreatitis and cancer

Peptides for microbe-induced cancers: latest therapeutic strategies and their advanced technologies

Cancer is a significant global health concern associated with multiple distinct factors, including microbial and viral infections. Numerous studies have elucidated the role of microorganisms, such as Helicobacter pylori (H. pylori), as well as viruses for example human papillomavirus (HPV), hepatitis B virus (HBV), and hepatitis C virus (HCV), in the development of human malignancies. Substantial attention has been focused on the treatment of these microorganism- and virus-associated cancers, with promising outcomes observed in studies employing peptide-based therapies. The current paper provides an overview of microbe- and virus-induced cancers and their underlying molecular mechanisms. We discuss an assortment of peptide-based therapies which are currently being developed, including tumor-targeting peptides and microbial/viral peptide-based vaccines. We describe the major technological advancements that have been made in the design, screening, and delivery of peptides as anticancer agents. The primary focus of the current review is to provide insight into the latest research and development in this field and to provide a realistic glimpse into the future of peptide-based therapies for microbe- and virus-induced neoplasms.

Alterations of the bile microbiome is associated with progression-free survival in pancreatic ductal adenocarcinoma patients

BACKGROUND

Patients with pancreatic ductal adenocarcinoma (PDAC) display an altered oral, gastrointestinal, and intra-pancreatic microbiome compared to healthy individuals. However, knowledge regarding the bile microbiome and its potential impact on progression-free survival in PDACs remains limited.

METHODS

Patients with PDAC (n = 45), including 20 matched pairs before and after surgery, and benign controls (n = 16) were included prospectively. The characteristics of the microbiomes of the total 81 bile were revealed by 16  S-rRNA gene sequencing. PDAC patients were divided into distinct groups based on tumor marker levels, disease staging, before and after surgery, as well as progression free survival (PFS) for further analysis. Disease diagnostic model was formulated utilizing the random forest algorithm.

RESULTS

PDAC patients harbor a unique and diverse bile microbiome (PCoA, weighted Unifrac, p = 0.038), and the increasing microbial diversity is correlated with dysbiosis according to key microbes and microbial functions. Aliihoeflea emerged as the genus displaying the most significant alteration among two groups (p < 0.01). Significant differences were found in beta diversity of the bile microbiome between long-term PFS and short-term PFS groups (PCoA, weighted Unifrac, p = 0.005). Bacillota and Actinomycetota were identified as altered phylum between two groups associated with progression-free survival in all PDAC patients. Additionally, we identified three biomarkers as the most suitable set for the random forest model, which indicated a significantly elevated likelihood of disease occurrence in the PDAC group (p < 0.0001). The area under the receiver operating characteristic (ROC) curve reached 80.8% with a 95% confidence interval ranging from 55.0 to 100%. Due to the scarcity of bile samples, we were unable to conduct further external verification.

CONCLUSION

PDAC is characterized by an altered microbiome of bile ducts. Biliary dysbiosis is linked with progression-free survival in all PDACs. This study revealed the alteration of the bile microbiome in PDACs and successfully developed a diagnostic model for PDAC.

Absence of a pancreatic microbiome in intraductal papillary mucinous neoplasm

OBJECTIVE

This study aims to validate the existence of a microbiome within intraductal papillary mucinous neoplasm (IPMN) that can be differentiated from the taxonomically diverse DNA background of next-generation sequencing procedures.

DESIGN

We generated 16S rRNA amplicon sequencing data to analyse 338 cyst fluid samples from 190 patients and 19 negative controls, the latter collected directly from sterile syringes in the operating room. A subset of samples (n=20) and blanks (n=5) were spiked with known concentrations of bacterial cells alien to the human microbiome to infer absolute abundances of microbial traces. All cyst fluid samples were obtained intraoperatively and included IPMNs with various degrees of dysplasia as well as other cystic neoplasms. Follow-up culturing experiments were conducted to assess bacterial growth for microbiologically significant signals.

RESULTS

Microbiome signatures of cyst fluid samples were inseparable from those of negative controls, with no difference in taxonomic diversity, and microbial community composition. In a patient subgroup that had recently undergone invasive procedures, a bacterial signal was evident. This outlier signal was not characterised by higher taxonomic diversity but by an increased dominance index of a gut-associated microbe, leading to lower taxonomic evenness compared with the background signal.

CONCLUSION

The 'microbiome' of IPMNs and other pancreatic cystic neoplasms does not deviate from the background signature of negative controls, supporting the concept of a sterile environment. Outlier signals may appear in a small fraction of patients following recent invasive endoscopic procedures. No associations between microbial patterns and clinical or cyst parameters were apparent.

The bacterial metabolite, lithocholic acid, has antineoplastic effects in pancreatic adenocarcinoma

Lithocholic acid (LCA) is a secondary bile acid. LCA enters the circulation after bacterial synthesis in the gastrointestinal tract, reaches distantly located cancer cells, and influences their behavior. LCA was considered carcinogenic, but recent studies demonstrated that LCA has antitumor effects. We assessed the possible role of LCA in pancreatic adenocarcinoma. At the serum reference concentration, LCA induced a multi-pronged antineoplastic program in pancreatic adenocarcinoma cells. LCA inhibited cancer cell proliferation and induced mesenchymal-to-epithelial (MET) transition that reduced cell invasion capacity. LCA induced oxidative/nitrosative stress by decreasing the expression of nuclear factor, erythroid 2-like 2 (NRF2) and inducing inducible nitric oxide synthase (iNOS). The oxidative/nitrosative stress increased protein nitration and lipid peroxidation. Suppression of oxidative stress by glutathione (GSH) or pegylated catalase (pegCAT) blunted LCA-induced MET. Antioxidant genes were overexpressed in pancreatic adenocarcinoma and decreased antioxidant levels correlated with better survival of pancreatic adenocarcinoma patients. Furthermore, LCA treatment decreased the proportions of cancer stem cells. Finally, LCA induced total and ATP-linked mitochondrial oxidation and fatty acid oxidation. LCA exerted effects through the farnesoid X receptor (FXR), vitamin D receptor (VDR), and constitutive androstane receptor (CAR). LCA did not interfere with cytostatic agents used in the chemotherapy of pancreatic adenocarcinoma. Taken together, LCA is a non-toxic compound and has antineoplastic effects in pancreatic adenocarcinoma.

Heterogeneous changes in gut and tumor microbiota in patients with pancreatic cancer: insights from clinical evidence

BACKGROUND

Pancreatic cancer is the foremost contributor to cancer-related deaths globally, and its prevalence continues to rise annually. Nevertheless, the underlying mechanisms behind its development remain unclear and necessitate comprehensive investigation.

METHODS

In this study, a total of 29 fresh stool samples were collected from patients diagnosed with pancreatic cancer. The gut microbial data of healthy controls were obtained from the SRA database (SRA data number: SRP150089). Additionally, 28 serum samples and diseased tissues were collected from 14 patients with confirmed pancreatic cancer and 14 patients with chronic pancreatitis. Informed consent was obtained from both groups of patients. Microbial sequencing was performed using 16s rRNA.

RESULTS

The results showed that compared with healthy controls, the species abundance index of intestinal flora in patients with pancreatic cancer was increased (P < 0.05), and the number of beneficial bacteria at the genus level was reduced (P < 0.05). Compared with patients with chronic pancreatitis, the expression levels of CA242 and CA199 in the serum of patients with pancreatic cancer were increased (P < 0.05). The bacterial richness index of tumor microorganisms in patients with pancreatic cancer increased, while the diversity index decreased(P < 0.05). Furthermore, there was a change in the species composition at the genus level. Additionally, the expression level of CA242 was found to be significantly positively correlated with the relative abundance of Acinetobacter(P < 0.05).

CONCLUSION

Over all, the expression levels of serum tumor markers CA242 and CA19-9 in patients with pancreatic cancer are increased, while the beneficial bacteria in the intestine and tumor microenvironment are reduced and pathogenic bacteria are increased. Acinetobacter is a specific bacterial genus highly expressed in pancreatic cancer tissue.

Integrative metagenomic and metabolomic analyses reveal the potential of gut microbiota to exacerbate acute pancreatitis

Early dysbiosis in the gut microbiota may contribute to the severity of acute pancreatitis (AP), however, a comprehensive understanding of the gut microbiome, potential pathobionts, and host metabolome in individuals with AP remains elusive. Hence, we employed fecal whole-metagenome shotgun sequencing in 82 AP patients and 115 matched healthy controls, complemented by untargeted serum metabolome and lipidome profiling in a subset of participants. Analyses of the gut microbiome in AP patients revealed reduced diversity, disrupted microbial functions, and altered abundance of 77 species, influenced by both etiology and severity. AP-enriched species, mostly potential pathobionts, correlated positively with host liver function and serum lipid indicators. Conversely, many AP-depleted species were short-chain fatty acid producers. Gut microflora changes were accompanied by shifts in the serum metabolome and lipidome. Specifically, certain gut species, like enriched Bilophila wadsworthia and depleted Bifidobacterium spp., appeared to contribute to elevated triglyceride levels in biliary or hyperlipidemic AP patients. Through culturing and whole-genome sequencing of bacterial isolates, we identified virulence factors and clinically relevant antibiotic resistance in patient-derived strains, suggesting a predisposition to opportunistic infections. Finally, our study demonstrated that gavage of specific pathobionts could exacerbate pancreatitis in a caerulein-treated mouse model. In conclusion, our comprehensive analysis sheds light on the gut microbiome and serum metabolome in AP, elucidating the role of pathobionts in disease progression. These insights offer valuable perspectives for etiologic diagnosis, prevention, and intervention in AP and related conditions.

Microbial profile in bile from pancreatic and extra-pancreatic biliary tract cancer

BACKGROUND

Dysbiotic biliary bacterial profile is reported in cancer patients and is associated with survival and comorbidities, raising the question of its effect on the influence of anticancer drugs and, recently, the suggestion of perichemotherapy antibiotics in pancreatic cancer patients colonized by the Escherichia coli and Klebsiella pneumoniae.

OBJECTIVE

In this study, we investigated the microbial communities that colonize tumours and which bacteria could aid in diagnosing pancreatic and biliary cancer and managing bile-colonized patients.

METHODS

A retrospective study on positive bile cultures of 145 Italian patients who underwent cholangiopancreatography with PC and EPC cancer hospitalized from January 2006 to December 2020 in a QA-certified academic surgical unit were investigated for aerobic/facultative-anaerobic bacteria and fungal organisms.

RESULTS

We found that among Gram-negative bacteria, Escherichia coli and Pseudomonas spp were the most frequent in the EPC group, while Escherichia coli, Klebsiella spp, and Pseudomonas spp were the most frequent in the PC group. Enterococcus spp was the most frequent Gram-positive bacteria in both groups. Comparing the EPC and PC, we found a significant presence of patients with greater age in the PC compared to the EPC group. Regarding Candida spp, we found no significant but greater rate in the PC group compared to the EPC group (11.7% vs 1.96%). We found that Alcaligenes faecalis was the most frequent bacteria in EPC than the PC group, among Gram-negative bacterial species.

CONCLUSIONS

Age differences in gut microbiota composition may affect biliary habitats in our cancer population, especially in patients with pancreatic cancer. Alcaligenes faecalis isolated in the culture of bile samples could represent potential microbial markers for a restricted follow-up to early diagnosis of extra-pancreatic cancer. Finally, the prevalence of Candida spp in pancreatic cancer seems to trigger new aspects about debate about the role of fungal microbiota into their relationship with pancreatic cancer.

Understanding bacterial infiltration of the pancreas through a deformable pancreatic duct

Tiny amount of bacteria are found in the pancreas in pancreatitis and cancer, which seemed involved in inflammation and carcinogenesis. However, bacterial infiltration from the duodenum is inhibited by the physical defense mechanisms such as bile flow and the sphincter of Oddi. To understand how the bacteria possibly infiltrate the pancreas through a deformable pancreatic duct, influenced by the periodic contractions of the sphincter of Oddi, a mathematical model of bacterial infiltration is developed that considered large deformation, fluid flow, and bacterial transport in a deformable pancreatic duct. In addition, the sphincter's contraction wave is modeled by including its propagation from the pancreas toward the duodenum. Simulated structure of the deformed duct with the relaxed sphincter and simulated bile distribution agreed reasonably well with the literature, validating the model. Bacterial infiltration from the duodenum in a deformable pancreatic duct, following the sphincter's contraction, is counteracted by a gradual peristalsis-like deformation of the pancreatic duct, due to an antegrade contraction wave propagation from the pancreas to the duodenum, Parametric sensitivity analysis demonstrated that bacterial infiltration is increased with lower bile and pancreatic juice flow rate, greater contraction amplitude and frequency, thinner wall thickness, and retrograde contraction wave propagation. Since contraction waves following retrograde propagation are increased in patients with common bile duct stones and pancreatitis, they may possibly be factors for continuum inflammation of pancreas. (224 words).

Clostridium butyricum and its metabolite butyrate promote ferroptosis susceptibility in pancreatic ductal adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with limited therapeutic options. The diversity and composition of the intratumoral microbiota are associated with PDAC outcomes, and modulating the tumor microbiota has the potential to influence tumor growth and the host immune response. Here, we explore whether intervention with butyrate-producing probiotics can limit PDAC progression.

METHODS

Based on the TCGA (PAAD) database, we analyzed the differential communities of intratumoral microbiota in PDAC patients with long survival and short survival and explored the relevant mechanisms of Clostridium butyricum and its metabolite butyrate in the treatment of PDAC. Treatment with Clostridium butyricum or butyrate in combination with the ferroptosis inducer RSL3 in a PDAC mouse model has an inhibitory effect on PDAC progression. The potential molecular mechanisms were verified by flow cytometry, RNA-seq, Western blotting, qRT‒PCR and immunofluorescence.

RESULTS

We found that the tumoral butyrate-producing microbiota was linked to a better prognosis and less aggressive features of PDAC. Intervention with Clostridium butyricum or its metabolite butyrate triggered superoxidative stress and intracellular lipid accumulation, which enhanced ferroptosis susceptibility in PDAC.

CONCLUSION

Our study reveals a novel antitumor mechanism of butyrate and suggests the therapeutic potential of butyrate-producing probiotics in PDAC.

Mechanisms by which the intestinal microbiota affects gastrointestinal tumours and therapeutic effects

The intestinal microbiota is considered to be a forgotten organ in human health and disease. It maintains intestinal homeostasis through various complex mechanisms. A significant body of research has demonstrated notable differences in the gut microbiota of patients with gastrointestinal tumours compared to healthy individuals. Furthermore, the dysregulation of gut microbiota, metabolites produced by gut bacteria, and related signal pathways can partially explain the mechanisms underlying the occurrence and development of gastrointestinal tumours. Therefore, this article summarizes the latest research progress on the gut microbiota and gastrointestinal tumours. Firstly, we provide an overview of the composition and function of the intestinal microbiota and discuss the mechanisms by which the intestinal flora directly or indirectly affects the occurrence and development of gastrointestinal tumours by regulating the immune system, producing bacterial toxins, secreting metabolites. Secondly, we present a detailed analysis of the differences of intestinal microbiota and its pathogenic mechanisms in colorectal cancer, gastric cancer, hepatocellular carcinoma, etc. Lastly, in terms of treatment strategies, we discuss the effects of the intestinal microbiota on the efficacy and toxic side effects of chemotherapy and immunotherapy and address the role of probiotics, prebiotics, FMT and antibiotic in the treatment of gastrointestinal tumours. In summary, this article provides a comprehensive review of the pathogenic mechanisms of and treatment strategies pertaining to the intestinal microbiota in patients with gastrointestinal tumours. And provide a more comprehensive and precise scientific basis for the development of microbiota-based treatments for gastrointestinal tumours and the prevention of such tumours.

Bile Microbiome Signatures Associated with Pancreatic Ductal Adenocarcinoma Compared to Benign Disease: A UK Pilot Study

Pancreatic ductal adenocarcinoma (PDAC) has a very poor survival. The intra-tumoural microbiome can influence pancreatic tumourigenesis and chemoresistance and, therefore, patient survival. The role played by bile microbiota in PDAC is unknown. We aimed to define bile microbiome signatures that can effectively distinguish malignant from benign tumours in patients presenting with obstructive jaundice caused by benign and malignant pancreaticobiliary disease. Prospective bile samples were obtained from 31 patients who underwent either Endoscopic Retrograde Cholangiopancreatography (ERCP) or Percutaneous Transhepatic Cholangiogram (PTC). Variable regions (V3-V4) of the 16S rRNA genes of microorganisms present in the samples were amplified by Polymerase Chain Reaction (PCR) and sequenced. The cohort consisted of 12 PDAC, 10 choledocholithiasis, seven gallstone pancreatitis and two primary sclerosing cholangitis patients. Using the 16S rRNA method, we identified a total of 135 genera from 29 individuals (12 PDAC and 17 benign). The bile microbial beta diversity significantly differed between patients with PDAC vs. benign disease (Permanova p = 0.0173). The separation of PDAC from benign samples is clearly seen through unsupervised clustering of Aitchison distance. We found three genera to be of significantly lower abundance among PDAC samples vs. benign, adjusting for false discovery rate (FDR). These were Escherichia (FDR = 0.002) and two unclassified genera, one from Proteobacteria (FDR = 0.002) and one from Enterobacteriaceae (FDR = 0.011). In the same samples, the genus Streptococcus (FDR = 0.033) was found to be of increased abundance in the PDAC group. We show that patients with obstructive jaundice caused by PDAC have an altered microbiome composition in the bile compared to those with benign disease. These bile-based microbes could be developed into potential diagnostic and prognostic biomarkers for PDAC and warrant further investigation.

Pancreatic Cancer and Detection Methods

The pancreas is a vital organ with exocrine and endocrine functions. Pancreatitis is an inflammation of the pancreas caused by alcohol consumption and gallstones. This condition can heighten the risk of pancreatic cancer (PC), a challenging disease with a high mortality rate. Genetic and epigenetic factors contribute significantly to PC development, along with other risk factors. Early detection is crucial for improving PC outcomes. Diagnostic methods, including imagining modalities and tissue biopsy, aid in the detection and analysis of PC. In contrast, liquid biopsy (LB) shows promise in early tumor detection by assessing biomarkers in bodily fluids. Understanding the function of the pancreas, associated diseases, risk factors, and available diagnostic methods is essential for effective management and early PC detection. The current clinical examination of PC is challenging due to its asymptomatic early stages and limitations of highly precise diagnostics. Screening is recommended for high-risk populations and individuals with potential benign tumors. Among various PC screening methods, the N-NOSE plus pancreas test stands out with its high AUC of 0.865. Compared to other commercial products, the N-NOSE plus pancreas test offers a cost-effective solution for early detection. However, additional diagnostic tests are required for confirmation. Further research, validation, and the development of non-invasive screening methods and standardized scoring systems are crucial to enhance PC detection and improve patient outcomes. This review outlines the context of pancreatic cancer and the challenges for early detection.

Impact of gut microbiome in the development and treatment of pancreatic cancer: Newer insights

The gut microbiome plays an important role in the variation of pharmacologic response. This aspect is especially important in the era of precision medicine, where understanding how and to what extent the gut microbiome interacts with drugs and their actions will be key to individualizing therapy. The impact of the composition of the gut microbiome on the efficacy of newer cancer therapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell treatment has become an active area of research. Pancreatic adenocarcinoma (PAC) has a poor prognosis even in those with potentially resectable disease, and treatment options are very limited. Newer studies have concluded that there is a synergistic effect for immunotherapy in combination with cytotoxic drugs, in the treatment of PAC. A variety of commensal microbiota can affect the efficacy of conventional chemotherapy and immunotherapy by modulating the tumor microenvironment in the treatment of PAC. This review will provide newer insights on the impact that alterations made in the gut microbial system have in the development and treatment of PAC.

BLAB2CancerKD: a knowledge graph database focusing on the association between lactic acid bacteria and cancer, but beyond

In a broad sense, lactic acid bacteria (LAB) is a general term for Gram-positive bacteria that can produce lactic acid by utilizing fermentable carbohydrates. It is widely used in essential fields such as industry, agriculture, animal husbandry and medicine. At the same time, LAB are closely related to human health. They can regulate human intestinal flora and improve gastrointestinal function and body immunity. Cancer, a disease in which some cells grow out of control and spread to other body parts, is one of the leading causes of human death worldwide. In recent years, the potential of LAB in cancer treatment has attracted attention. Mining knowledge from the scientific literature significantly accelerates its application in cancer treatment. Using 7794 literature studies of LAB cancer as source data, we have processed 16 543 biomedical concepts and 23 091 associations by using automatic text mining tools combined with manual curation of domain experts. An ontology containing 31 434 pieces of structured data is constructed. Finally, based on ontology, a knowledge graph (KG) database, which is called Beyond 'Lactic acid bacteria to Cancer Knowledge graph Database' (BLAB2CancerKD), is constructed by using KG and web technology. BLAB2CancerKD presents all the relevant knowledge intuitively and clearly in various data presentation forms, and the interactive system function also makes it more efficient. BLAB2CancerKD will be continuously updated to advance the research and application of LAB in cancer therapy. Researchers can visit BLAB2CancerKD at. Database URL http://110.40.139.2:18095/.

Microbiota Regulates Pancreatic Cancer Carcinogenesis through Altered Immune Response

The microbiota is present in many parts of the human body and plays essential roles. The most typical case is the occurrence and development of cancer. Pancreatic cancer (PC), one of the most aggressive and lethal types of cancer, has recently attracted the attention of researchers. Recent research has revealed that the microbiota regulates PC carcinogenesis via an altered immune response. Specifically, the microbiota, in several sites, including the oral cavity, gastrointestinal tract, and pancreatic tissue, along with the numerous small molecules and metabolites it produces, influences cancer progression and treatment by activating oncogenic signaling, enhancing oncogenic metabolic pathways, altering cancer cell proliferation, and triggering chronic inflammation that suppresses tumor immunity. Diagnostics and treatments based on or in combination with the microbiota offer novel insights to improve efficiency compared with existing therapies.

Mechanisms of obesity- and diabetes mellitus-related pancreatic carcinogenesis: a comprehensive and systematic review

Research on obesity- and diabetes mellitus (DM)-related carcinogenesis has expanded exponentially since these two diseases were recognized as important risk factors for cancers. The growing interest in this area is prominently actuated by the increasing obesity and DM prevalence, which is partially responsible for the slight but constant increase in pancreatic cancer (PC) occurrence. PC is a highly lethal malignancy characterized by its insidious symptoms, delayed diagnosis, and devastating prognosis. The intricate process of obesity and DM promoting pancreatic carcinogenesis involves their local impact on the pancreas and concurrent whole-body systemic changes that are suitable for cancer initiation. The main mechanisms involved in this process include the excessive accumulation of various nutrients and metabolites promoting carcinogenesis directly while also aggravating mutagenic and carcinogenic metabolic disorders by affecting multiple pathways. Detrimental alterations in gastrointestinal and sex hormone levels and microbiome dysfunction further compromise immunometabolic regulation and contribute to the establishment of an immunosuppressive tumor microenvironment (TME) for carcinogenesis, which can be exacerbated by several crucial pathophysiological processes and TME components, such as autophagy, endoplasmic reticulum stress, oxidative stress, epithelial-mesenchymal transition, and exosome secretion. This review provides a comprehensive and critical analysis of the immunometabolic mechanisms of obesity- and DM-related pancreatic carcinogenesis and dissects how metabolic disorders impair anticancer immunity and influence pathophysiological processes to favor cancer initiation.

Microbiota in the Natural History of Pancreatic Cancer: From Predisposition to Therapy

Early microbiome insights came from gut microbes and their role among intestinal and extraintestinal disease. The latest evidence suggests that the microbiota is a true organ, capable of several interactions throughout the digestive system, attracting specific interest in the biliopancreatic district. Despite advances in diagnostics over the last few decades and improvements in the management of this disease, pancreatic cancer is still a common cause of cancer death. Microbiota can influence the development of precancerous disease predisposing to pancreatic cancer (PC). At the same time, neoplastic tissue shows specific characteristics in terms of diversity and phenotype, determining the short- and long-term prognosis. Considering the above information, a role for microbiota has also been hypothesized in the different phases of the PC approach, providing future revolutionary therapeutic insights. Microbiota-modulating therapies could open new issues in the therapeutic landscape. The aim of this narrative review is to assess the most updated evidence on microbiome in all the steps regarding pancreatic adenocarcinoma, from early development to response to antineoplastic therapy and long-term prognosis.

Using proton pump inhibitors increases the risk of hepato-biliary-pancreatic cancer. A systematic review and meta-analysis

Background: More and more studies are focusing on the adverse effects and damage caused by PPI abuse, we carried out a systematic review and meta-analysis for assessing whether the proton pump inhibitor (PPI) leads to hepato-biliary-pancreatic cancer.

Methods: PubMed, EMBASE and Web of Science were searched until 1 July 2022, 25 studies (17 case-control and 8 cohort studies; 2741853 individuals) included in this study. Pooled Odd Ratios (ORs) were used for random effect models. Sensitivity analysis and dose-response analysis, subgroup analysis were all conducted.

Results: The aggregate OR of the meta-analysis was 1.69 (95% confidence interval (CI): 1.42–2.01, p = 0.01) and heterogeneity (I² = 98.9%, p < 0.001) was substantial. According to stratified subgroup analyses, the incidence of hepato-biliary-pancreatic cancer was associated, expect for study design, study quality and region. Risk of hepato-biliary-pancreatic cancer is highest when people is treated with normal doses of PPI. The risks decrease and become insignificant when the cumulative defined daily dose (cDDD) increases.

Conclusion: The use of PPI may be associated with an increased risk of hepato-biliary-pancreatic cancer. Hence, caution is needed when using PPIs among patients with a high risk of hepato-biliary-pancreatic cancer.

A systematic review on omics data (metagenomics, metatranscriptomics, and metabolomics) in the role of microbiome in gallbladder disease

Microbiotas are the range of microorganisms (mainly bacteria and fungi) colonizing multicellular, macroscopic organisms. They are crucial for several metabolic functions affecting the health of the host. However, difficulties hamper the investigation of microbiota composition in cultivating microorganisms in standard growth media. For this reason, our knowledge of microbiota can benefit from the analysis of microbial macromolecules (DNA, transcripts, proteins, or by-products) present in various samples collected from the host. Various omics technologies are used to obtain different data. Metagenomics provides a taxonomical profile of the sample. It can also be used to obtain potential functional information. At the same time, metatranscriptomics can characterize members of a microbiome responsible for specific functions and elucidate genes that drive the microbiotas relationship with its host. Thus, while microbiota refers to microorganisms living in a determined environment (taxonomy of microorganisms identified), microbiome refers to the microorganisms and their genes living in a determined environment and, of course, metagenomics focuses on the genes and collective functions of identified microorganisms. Metabolomics completes this framework by determining the metabolite fluxes and the products released into the environment. The gallbladder is a sac localized under the liver in the human body and is difficult to access for bile and tissue sampling. It concentrates the bile produced in the hepatocytes, which drains into bile canaliculi. Bile promotes fat digestion and is released from the gallbladder into the upper small intestine in response to food. Considered sterile originally, recent data indicate that bile microbiota is associated with the biliary tract’s inflammation and carcinogenesis. The sample size is relevant for omic studies of rare diseases, such as gallbladder carcinoma. Although in its infancy, the study of the biliary microbiota has begun taking advantage of several omics strategies, mainly based on metagenomics, metabolomics, and mouse models. Here, we show that omics analyses from the literature may provide a more comprehensive image of the biliary microbiota. We review studies performed in this environmental niche and focus on network-based approaches for integrative studies.

The Oncobiome in Gastroenteric and Genitourinary Cancers

Early evidence suggests a strong association of microorganisms with several human cancers, and great efforts have been made to understand the pathophysiology underlying microbial carcinogenesis. Bacterial dysbiosis causes epithelial barrier failure, immune dysregulation and/or genotoxicity and, consequently, creates a tumor-permissive microenvironment. The majority of the bacteria in our body reside in the gastrointestinal tract, known as gut microbiota, which represents a complex and delicate ecosystem. Gut microbes can reach the pancreas, stomach and colon via the bloodstream. Oral bacterial translocations can also occur. In the stomach, pancreas and colon, low microbial diversity is associated with cancer, in particular with a bad prognosis. The urogenital tract also harbors unique microbiota, distinct from the gut microbiota, which might have a role in the urinary and female/male reproductive cancers’ pathogenesis. In healthy women, the majority of bacteria reside in the vagina and cervix and unlike other mucosal sites, the vaginal microbiota exhibits low microbial diversity. Genital dysbiosis might have an active role in the development and/or progression of gynecological malignancies through mechanisms including modulation of oestrogen metabolism. Urinary dysbiosis may influence the pathogenesis of bladder cancer and prostate cancer in males. Modulation of the microbiome via pre, pro and postbiotics, fecal or vaginal microbiota transplantation and engineering bacteria might prove useful in improving cancer treatment response and quality of life. Elucidating the complex host-microbiome interactions will result in prevention and therapeutic efficacy interventions.

Elevation of enterococcus-specific antibodies associated with bacterial translocation is predictive of survival rate in chronic liver disease

Introduction/purpose

The gut-liver axis contributes to disease progression, a rise in infection rate, organ failure and a poor overall outcome in chronic liver diseases (CLD). Monitoring of the gut-liver axis is critical in understanding disease status, but biomarkers have not been elucidated. The aim of this study is to determine the level of serum antibodies against Enterococcus (E.) faecalis in evaluating patients with CLD, including those treated with rifaximin (a minimally absorbed antibiotic), and in patients with alcohol-associated liver disease (ALD).

Materials and methods

We enrolled 109 CLD patients (cohort 1), 30 hepatic encephalopathy patients treated with rifaximin (cohort 2), 53 inpatients with ALD undergoing alcohol cessation (cohort 3) and 33 healthy subjects. To assess the consequences of E. faecalis translocation, we developed an assay for the detection of a serum antibody against E. faecalis capsular polysaccharide (E.CPS).

Results

Serum E.CPS antibody titer was elevated only in those patients with advanced CLD and ALD. The E.CPS antibody titer was an independent prognostic factor (p &lt; 0.05), while Mac-2 binding protein and albumin-bilirubin score were not independent predictors of survival. The improvement of predictive model in integrated factors was significant [continuous net reclassification index (value 0.699, p &lt; 0.05) and integrated discrimination improvement (value 0.164, p = 0.051)]. Furthermore, rifaximin treatment led to a decrease of serum E.CPS antibody titer resulting in a significantly longer overall rate of survival.

Conclusion

The E.CPS antibody titer appears to be a strong predictor of survival in CLD patients. Serum E.CPS levels decrease in CLD patients receiving rifaximin, and may be associated with an overall improvement in rate of survival.

Gut microbiota: Role and Association with Tumorigenesis in Different Malignancies

The microbiota has been associated with different cancer and may vary from patient to patient. A specific microbial strain can alter the progression of cancer and therapeutic outcome in response to anti-cancer therapy. The variations in microbiota contributed due to the individual microbiome of the microorganism are responsible for diverse clinical outcomes. The expansion of microbiota subpopulation during dysbiosis can lead to toxin production, inducing inflammation and cancer. The microbiota can be a dual-edged sword because it can be tumor-suppressive or oncogenic in the case of the gut. The transition of cancer cells from early to late-stage also impacts the composition of the microbiota, and this alteration could change the behavior of cancer. Multi-omics platforms derived data from an individual's multi-dimensional data (DNA, mRNA, microRNA, protein, metabolite, microbiota, and microbiome), i.e., individualome, to exploit it for personalized tailored treatment for different cancers in a precise manner. A number of studies suggest the importance of microbiota and its add-in suitability to existing treatment options for different malignancies. Furthermore, in vitro, and in vivo studies and cancer clinical trials suggest that probiotics have driven modulation of gut microbiota and other sites discourage the aggressive behavior and progression of different cancers.

Cancer as microenvironmental, systemic and environmental diseases: opportunity for transdisciplinary microbiomics science

Cancer is generally regarded as a localised disease, with the well-established role of the tumour microenvironment. However, the realm of cancer goes beyond the tumour microenvironment, and cancer should also be regarded as a systemic and environmental disease. The exposome (ie, the totality of exposures), which encompasses diets, supplements, smoking, alcohol, other lifestyle factors, medications, etc, likely alters the microbiome (inclusive of bacteria, viruses, archaea, fungi, parasites, etc) and immune system in various body sites and influences tumour phenotypes. The systemic metabolic/inflammatory status, which is likely influenced by exposures and intestinal physiological changes, may affect tissue microenvironment of colorectum and any other organs. Germline genomic factors can modify disease phenotypes via gene-by-environment interactions. Although challenges exist, it is crucial to advance not only basic experimental research that can analyse the effects of exposures, microorganisms and microenvironmental components on tumour evolution but also interdisciplinary human population research that can dissect the complex pathogenic roles of the exposome, microbiome and immunome. Metagenomic, metatranscriptomic and metabolomic analyses should be integrated into well-designed population research combined with advanced methodologies of artificial intelligence and molecular pathological epidemiology. Ideally, a prospective cohort study design that enables biospecimen (such as stool) collection before disease detection should be considered to address reverse causation and recall biases. Robust experimental and observational research together can provide insights into dynamic interactions between environmental exposures, microbiota, tumour and immunity during carcinogenesis processes, thereby helping us develop precision prevention and therapeutic strategies to ultimately reduce the cancer burden.

An Exploration of Oral-Gut Pathogens Mediating Immune Escape of Pancreatic Cancer via miR-21/PTEN Axis

Oral-gut pathogens are closely associated with pancreatic cancer, such as Campylobacter jejuni, Clostridium difficile, Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Porphyromonas gingivalis, and Vibrio cholera, but the related mechanisms remain not well understood. Phosphatase and tensin homolog (PTEN, a widely known tumor suppressor) play a key role in the anti-cancer immune system. Pancreatic cancer cells with PTEN loss are often in the immunosuppressive tumor microenvironment regulated by myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and M2 macrophages, which are regarded as the mechanism in the immune escape of cancers. The miR-21, as an oncogene in human cancers, plays an important role in pancreatic cancer progression, downregulates the levels of PTEN, and may promote cancer to evade host immune surveillance. Some oral-gut pathogens have been found to promote miR-21 expression and reduce PTEN expression. On the other hand, most gut pathogens infection is thought to produce reactive oxygen species (ROS) or activate inflammatory cytokines, which may also induce ROS-mediated miR-21 expression. These pathogens' infection is involved with the cell density of MDSCs, Tregs, and M2 macrophages. Therefore, it is quite reasonable to propose that oral-gut pathogens possibly promote pancreatic cancer escaping from host immune surveillance by activating the miR-21/PTEN axis and immune-suppressive cells. The present exploration suggests that an increased understanding of the pattern of the effects of gut pathogens on the miR-21/PTEN axis will lead to better insights into the specific mechanisms associated with the immune escape of pancreatic cancer caused by oral-gut microbiota.

Role of the microbiome in oral cancer occurrence, progression and therapy

The oral cavity, like other digestive or mucosal sites, contains a site-specific microbiome that plays a significant role in maintaining health and homeostasis. Strictly speaking, the gastrointestinal tract starts from the oral cavity, with special attention paid to the specific flora of the oral cavity. In healthy people, the microbiome of the oral microenvironment is governed by beneficial bacteria, that benefit the host by symbiosis. When a microecological imbalance occurs, changes in immune and metabolic signals affect the characteristics of cancer, as well as chronic inflammation, disruption of the epithelial barrier, changes in cell proliferation and cell apoptosis, genomic instability, angiogenesis, and epithelial barrier destruction and metabolic regulation. These pathophysiological changes could result in oral cancer. Rising evidence suggests that oral dysbacteriosis and particular microbes may play a positive role in the evolution, development, progression, and metastasis of oral cancer, for instance, oral squamous cell carcinoma (OSCC) through direct or indirect action.

Complex Role of Microbiome in Pancreatic Tumorigenesis: Potential Therapeutic Implications

Pancreatic cancer (PC) is the fourth leading cause of cancer-related mortality with limited diagnostic and therapeutic options. Although immunotherapy has shown promise in the treatment of several cancers, its role in pancreatic cancer is rather limited. Several studies have focused on determining the role of the tumor microenvironment with cancer-cell-intrinsic events and tumor-infiltrating immune cellular properties. However, in the past decade, there has been emerging research aimed at delineating the role of the host microbiome, including the metabolites from microbes and host responses, on pancreatic tumorigenesis. Importantly, there is emerging evidence suggesting the beneficial role of a gut microbiome transplant to improve immunotherapeutic outcomes in cancer patients. In this review, we summarize the recent understanding of the role of the microbiome in pancreatic cancer progression, along with its clinical diagnostic and therapeutic implications.

Sequestration of Intestinal Acidic Toxins by Cationic Resin Attenuates Pancreatic Cancer Progression through Promoting Autophagic Flux for YAP Degradation

Simple Summary

Annually, more than 450,000 people are diagnosed with pancreatic cancer worldwide with over 430,000 mortalities. Pancreatic ductal carcinoma (PDAC) accounts for around 80% of pancreatic cancer cases with an extremely high mortality rate. Emerging research has demonstrated that gut dysbiosis is closely associated with pancreatic cancer, while the underlying mechanisms remain elusive. In this study, we found that elevated levels of endotoxin (LPS) and bile acids were associated with malignant progression in Kras-driven pancreatic cancer mice. Importantly, oral administration of cationic resins to sequestrate intestinal endotoxins and bile acids efficiently attenuated tumor progression. Thus, sequestration of intestinal acidic toxins by oral administration of cationic resins may have potential as an intervention strategy for pancreatic malignancy.

Abstract

Pancreatic cancer is driven by risk factors such as diabetes and chronic pancreatic injury, which are further associated with gut dysbiosis. Intestinal toxins such as bile acids and bacterial endotoxin (LPS), in excess and persistence, can provoke chronic inflammation and tumorigenesis. Of interest is that many intestinal toxins are negatively charged acidic components in essence, which prompted us to test whether oral administration of cationic resin can deplete intestinal toxins and ameliorate pancreatic cancer. Here, we found that increased plasma levels of endotoxin and bile acids in Pdx1-Cre: LSL-Kras^G12D/+ mice were associated with the transformation of the pancreatic ductal carcinoma (PDAC) state. Common bile-duct-ligation or LPS injection impeded autolysosomal flux, leading to Yap accumulation and malignant transformation. Conversely, oral administration of cholestyramine to sequestrate intestinal endotoxin and bile acids resumed autolysosomal flux for Yap degradation and attenuated metastatic incidence. Conversely, chloroquine treatment impaired autolysosomal flux and exacerbated malignance, showing jeopardization of p62/ Sqxtm1 turnover, leading to Yap accumulation, which is also consistent with overexpression of cystatin A (CSTA) in situ with pancreatic cancer cells and metastatic tumor. At cellular levels, chenodeoxycholic acid or LPS treatment activated the ligand–receptor-mediated AKT-mTOR pathway, resulting in autophagy-lysosomal stress for YAP accumulation and cellular dissemination. Thus, this work indicates a potential new strategy for intervention of pancreatic metastasis through sequestration of intestinal acidic toxins by oral administration of cationic resins.

Isolation of pancreatic microbiota from cystic precursors of pancreatic cancer with intracellular growth and DNA damaging properties

Emerging research suggests gut microbiome may play a role in pancreatic cancer initiation and progression, but cultivation of the cancer microbiome remains challenging. This pilot study aims to investigate the possibility to cultivate pancreatic microbiome from pancreatic cystic lesions associated with invasive cancer. Intra-operatively acquired pancreatic cyst fluid samples showed culture-positivity mainly in the intraductal papillary mucinous neoplasm (IPMN) group of lesions. MALDI-TOF MS profiling analysis shows Gammaproteobacteria and Bacilli dominate among individual bacteria isolates. Among cultivated bacteria, Gammaproteobacteria, particularly Klebsiella pneumoniae, but also Granulicatella adiacens and Enterococcus faecalis, demonstrate consistent pathogenic properties in pancreatic cell lines tested in ex vivo co-culture models. Pathogenic properties include intracellular survival capability, cell death induction, or causing DNA double-strand breaks in the surviving cells resembling genotoxic effects. This study provides new insights into the role of the pancreatic microbiota in the intriguing link between pancreatic cystic lesions and cancer.

A Comprehensive Review of the Current and Future Role of the Microbiome in Pancreatic Ductal Adenocarcinoma

Simple Summary

This review summarizes the current literature related to the microbiome and pancreatic ductal adenocarcinoma (PDAC). The aim of this review is to explore the current role of the microbiome in the disease process, screening/diagnostics and to postulate the future role with regards to therapeutic strategies including chemotherapy, immunotherapy and surgery. We further explore the future of microbiome modulation (faecal microbiome transplants, bacterial consortiums, anti-microbials and probiotics), their applications and how we can improve the future of microbiome modulation in a bid to improve PDAC outcomes.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second most common cause of cancer death in the USA by 2030, yet progress continues to lag behind that of other cancers, with only 9% of patients surviving beyond 5 years. Long-term survivorship of PDAC and improving survival has, until recently, escaped our understanding. One recent frontier in the cancer field is the microbiome. The microbiome collectively refers to the extensive community of bacteria and fungi that colonise us. It is estimated that there is one to ten prokaryotic cells for each human somatic cell, yet, the significance of this community in health and disease has, until recently, been overlooked. This review examines the role of the microbiome in PDAC and how it may alter survival outcomes. We evaluate the possibility of employing microbiomic signatures as biomarkers of PDAC. Ultimately this review analyses whether the microbiome may be amenable to targeting and consequently altering the natural history of PDAC.

The Role of Gut Microbiota in Gastrointestinal Tract Cancers

Disturbances in gastrointestinal (GI) microbiota could play a significant role in the development of GI cancers, but the underlying mechanisms remain largely unclear. While some bacteria seem to facilitate carcinogenesis, others appear to be protective. So far only one bacterium (Helicobacter pylori) has been classified by the International Agency for Cancer Research as carcinogenic in humans but many other are the subject of intense research. Most studies on the role of microbiota in GI tract oncogenesis focus on pancreatic and colorectal cancers with the following three species: Helicobacter pylori, Escherichia coli, and Porphyromonas gingivalis as likely causative factors. This review summarizes the role of bacteria in GI tract oncogenesis.

Enterococcus spp. have higher fitness for survival, in a pH-dependent manner, in pancreatic juice among duodenal bacterial flora

Background and Aim

Bacterial infection is involved in the progression of many gastrointestinal diseases, including those of pancreas; however, how and which bacteria colonize in pancreatic juice and tissue have yet to be elucidated. Recently, we reported that Enterococcus faecalis exists in the pancreatic juice and tissues of patients with chronic pancreatic disease. Here, we investigated the survival of E. faecalis in duodenal juice with different pH conditions.

Methods

Pancreatic juice samples from 62 patients with cancers of the duodeno‐pancreato‐biliary region were evaluated for the presence of E. faecalis. 16S ribosomal RNA polymerase chain reaction and 16S‐based metagenome analyses were performed to determine the bacterial composition. The survival of E. faecalis in various pancreatic juice conditions was evaluated.

Results

Of 62 samples, 27% (17/62) were positive for Enterococcus spp., among which 71% (12/17) contained E. faecalis. Enterococcus spp. showed the highest fitness for survival in alkaline pancreatic juice among various bacterial species. The microbiome of pancreatic juice from patients with pancreatic and bile duct cancer showed diversity, but Enterococcus spp. were enriched among duodenal tumors and intraductal papillary mucinous neoplasms.

Conclusions

Alkalinity is one of the important factors for the selective survival of E. faecalis among microbiota. E. faecalis can colonize the pancreatic duct when the pancreatic juice condition is altered.

Microbiota in Pancreatic Diseases: A Review of the Literature

The gut microbiota is a critical element in the balance between human health and disease. Its impairment, defined as dysbiosis, is associated with gastroenterological and systemic diseases. Pancreatic secretions are involved in the composition and changes of the gut microbiota, and the gut microbiota may colonize the pancreatic parenchyma and be associated with the occurrence of diseases. The gut microbiota and the pancreas influence each other, resulting in a "gut microbiota-pancreas axis". Moreover, the gut microbiota may be involved in pancreatic diseases, both through direct bacterial colonization and an indirect effect of small molecules and toxins derived from dysbiosis. Pancreatic diseases such as acute pancreatitis, chronic pancreatitis, autoimmune pancreatitis, and pancreatic cancer are common gastroenterological diseases associated with high morbidity and mortality. The involvement of the microbiota in pancreatic diseases is increasingly recognized. Therefore, modifying the intestinal bacterial flora could have important therapeutic implications on these pathologies. The aim of this study is to review the literature to evaluate the alterations of the gut microbiota in pancreatic diseases, and the role of the microbiota in the treatment of these diseases.

Human Gut Microbiota in Health and Selected Cancers

The majority of the epithelial surfaces of our body, and the digestive tract, respiratory and urogenital systems, are colonized by a vast number of bacteria, archaea, fungi, protozoans, and viruses. These microbiota, particularly those of the intestines, play an important, beneficial role in digestion, metabolism, and the synthesis of vitamins. Their metabolites stimulate cytokine production by the human host, which are used against potential pathogens. The composition of the microbiota is influenced by several internal and external factors, including diet, age, disease, and lifestyle. Such changes, called dysbiosis, may be involved in the development of various conditions, such as metabolic diseases, including metabolic syndrome, type 2 diabetes mellitus, Hashimoto's thyroidis and Graves' disease; they can also play a role in nervous system disturbances, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and depression. An association has also been found between gut microbiota dysbiosis and cancer. Our health is closely associated with the state of our microbiota, and their homeostasis. The aim of this review is to describe the associations between human gut microbiota and cancer, and examine the potential role of gut microbiota in anticancer therapy.

Dietary Patterns and Associated Microbiome Changes that Promote Oncogenesis

The recent increases in cancer incidences have been linked to lifestyle changes that result in obesity and metabolic syndrome. It is now evident that these trends are associated with the profound changes that occur in the intestinal microbiome, producing altered microbial population signatures that interact, directly or indirectly, with potentially pro-carcinogenic molecular pathways of transcription, proliferation, and inflammation. The effects of the entire gut microbial population on overall health are complex, but individual bacteria are known to play important and definable roles. Recent detailed examinations of a large number of subjects show a tight correlation between habitual diets, fecal microbiome signatures, and markers of metabolic health. Diets that score higher in healthfulness or diversity such as plant-based diets, have altered ratios of specific bacteria, including an increase in short-chain fatty acid producers, which in turn have been linked to improved metabolic markers and lowered cancer risk. Contrarily, numerous studies have implicated less healthy, lower-scoring diets such as the Western diet with reduced intestinal epithelial defenses and promotion of specific bacteria that affect carcinogenic pathways. In this review, we will describe how different dietary patterns affect microbial populations in the gut and illustrate the subsequent impact of bacterial products and metabolites on molecular pathways of cancer development, both locally in the gut and systemically in distant organs.

Microbiota Alterations and Their Association with Oncogenomic Changes in Pancreatic Cancer Patients

Pancreatic cancer (PC) is an aggressive disease with a high mortality and poor prognosis. The human microbiome is a key factor in many malignancies, having the ability to alter host metabolism and immune responses and participate in tumorigenesis. Gut microbes have an influence on physiological functions of the healthy pancreas and are themselves controlled by pancreatic secretions. An altered oral microbiota may colonize the pancreas and cause local inflammation by the action of its metabolites, which may lead to carcinogenesis. The mechanisms behind dysbiosis and PC development are not completely clear. Herein, we review the complex interactions between PC tumorigenesis and the microbiota, and especially the question, whether and how an altered microbiota induces oncogenomic changes, or vice versa, whether cancer mutations have an impact on microbiota composition. In addition, the role of the microbiota in drug efficacy in PC chemo- and immunotherapies is discussed. Possible future scenarios are the intentional manipulation of the gut microbiota in combination with therapy or the utilization of microbial profiles for the noninvasive screening and monitoring of PC.

Enterococci from Raw-Milk Cheeses: Current Knowledge on Safety, Technological, and Probiotic Concerns

The present study is focused on the safety, technological characteristics, and probiotic evaluation of Enterococcus species from different artisanal raw milk dairy products, mainly cheeses with ripening. Apart from proteolytic and lipolytic activities, most enterococci show the ability to metabolize citrate and convert it to various aromatic compounds. Long-ripened cheeses therefore have a specific flavor that makes them different from cheeses produced from thermally treated milk with commercial starter cultures. In addition, enterococci are producers of bacteriocins effective against spoilage and pathogenic bacteria, so they can be used as food preservatives. However, the use of enterococci in the dairy industry should be approached with caution. Although originating from food, enterococci strains may carry various virulence factors and antibiotic-resistance genes and can have many adverse effects on human health. Still, despite their controversial status, the use of enterococci in the food industry is not strictly regulated since the existence of these so-called desirable and undesirable traits in enterococci is a strain-dependent characteristic. To be specific, the results of many studies showed that there are some enterococci strains that are safe for use as starter cultures or as probiotics since they do not carry virulence factors and antibiotic-resistance genes. These strains even exhibit strong health-promoting effects such as stimulation of the immune response, anti-inflammatory activity, hypocholesterolemic action, and usefulness in prevention/treatment of some diseases.

The Microbiome Tumor Axis: How the Microbiome Could Contribute to Clonal Heterogeneity and Disease Outcome in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers. It is characterized by a poor prognosis with a 5-year survival rate of only around 10% and an ongoing increase in death rate. Due to the lack of early and specific symptoms, most patients are diagnosed at an advanced or even metastasized stage, essentially limiting curative treatment options. However, even curative resection of the primary tumor and adjuvant therapy often fails to provide a long-term survival benefit. One reason for this dismal situation can be seen in the evolution of therapy resistances. Furthermore, PDAC is characterized by high intratumor heterogeneity, pointing towards an abundance of cancer stem cells (CSCs), which are regarded as essential for tumor initiation and drug resistance. Additionally, it was shown that the gut microbiome is altered in PDAC patients, promotes Epithelial-Mesenchymal-Transition (EMT), determines responses towards chemotherapy, and affects survival in PDAC patients. Given the established links between CSCs and EMT as well as drug resistance, and the emerging role of the microbiome in PDAC, we postulate that the composition of the microbiome of PDAC patients is a critical determinant for the abundance and plasticity of CSC populations and thus tumor heterogeneity in PDAC. Unravelling this complex interplay might pave the way for novel treatment strategies.

Pancreatic cancer in 2021: What you need to know to win

Pancreatic cancer is one of the solid tumors with the worst prognosis. Five-year survival rate is less than 10%. Surgical resection is the only potentially curative treatment, but the tumor is often diagnosed at an advanced stage of the disease and surgery could be performed in a very limited number of patients. Moreover, surgery is still associated with high post-operative morbidity, while other therapies still offer very disappointing results. This article reviews every aspect of pancreatic cancer, focusing on the elements that can improve prognosis. It was written with the aim of describing everything you need to know in 2021 in order to face this difficult challenge.

The role of microbiome in pancreatic cancer

Recent studies of the human microbiome have offered new insights into how the microbiome can impact cancer development and treatment. Specifically, in pancreatic ductal adenocarcinoma (PDAC), the microbiota has been shown to modulate PDAC risk, contribute to tumorigenesis, impact the tumor microenvironment, and alter treatment response. These findings provide rationale for further investigations into leveraging the microbiome to develop new strategies to diagnose and treat PDAC patients. There is growing evidence that microbiome analyses have the potential to become easily performed, non-invasive diagnostic, prognostic, and predictive biomarkers in pancreatic cancer. More excitingly, there is now emerging interest in developing interventions based on the modulation of microbiota. Fecal microbiota transplantation, probiotics, dietary changes, and antibiotics are all potential strategies to augment the efficacy of current therapeutics and reduce toxicities. While there are still challenges to overcome, this is a rapidly growing field that holds promise for translation into clinical practice and provides a new approach to improving patient outcomes.

The Role of the Oral Microbiota in the Etiopathogenesis of Oral Squamous Cell Carcinoma

Dysbiosis in the oral environment may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). This review aims to summarize the current knowledge about the association of oral microbiota with OSCC and to describe possible etiopathogenetic mechanisms involved in processes of OSCC development and progression. Association studies included in this review were designed as case–control/case studies, analyzing the bacteriome, mycobiome, and virome from saliva, oral rinses, oral mucosal swabs, or oral mucosal tissue samples (deep and superficial) and comparing the results in healthy individuals to those with OSCC and/or with premalignant lesions. Changes in relative abundances of specific bacteria (e.g., Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sp.) and fungi (especially Candida sp.) were associated with OSCC. Viruses can also play a role; while the results of studies investigating the role of human papillomavirus in OSCC development are controversial, Epstein–Barr virus was positively correlated with OSCC. The oral microbiota has been linked to tumorigenesis through a variety of mechanisms, including the stimulation of cell proliferation, tumor invasiveness, angiogenesis, inhibition of cell apoptosis, induction of chronic inflammation, or production of oncometabolites. We also advocate for the necessity of performing a complex analysis of the microbiome in further studies and of standardizing the sampling procedures by establishing guidelines to support future meta-analyses.

Pancreatic cancer: A review of epidemiology, trend, and risk factors

Despite rapid advances in modern medical technology and significant improvements in survival rates of many cancers, pancreatic cancer is still a highly lethal gastrointestinal cancer with a low 5-year survival rate and difficulty in early detection. At present, the incidence and mortality of pancreatic cancer are increasing year by year worldwide, no matter in the United States, Europe, Japan, or China. Globally, the incidence of pancreatic cancer is projected to increase to 18.6 per 100000 in 2050, with the average annual growth of 1.1%, meaning that pancreatic cancer will pose a significant public health burden. Due to the special anatomical location of the pancreas, the development of pancreatic cancer is usually diagnosed at a late stage with obvious clinical symptoms. Therefore, a comprehensive understanding of the risk factors for pancreatic cancer is of great clinical significance for effective prevention of pancreatic cancer. In this paper, the epidemiological characteristics, developmental trends, and risk factors of pancreatic cancer are reviewed and analyzed in detail.

Micro- and Mycobiota Dysbiosis in Pancreatic Ductal Adenocarcinoma Development

BACKGROUND

Dysbiosis of the intestinal flora has emerged as an oncogenic contributor in different malignancies. Recent findings suggest a crucial tumor-promoting role of micro- and mycobiome alterations also in the development of pancreatic ductal adenocarcinoma (PDAC).

METHODS

To summarize the current knowledge about this topic, a systematic literature search of articles published until October 2020 was performed in MEDLINE (PubMed).

RESULTS

An increasing number of publications describe associations between bacterial and fungal species and PDAC development. Despite the high inter-individual variability of the commensal flora, some studies identify specific microbial signatures in PDAC patients, including oral commensals like Porphyromonas gingivalis and Fusobacterium nucleatum or Gram-negative bacteria like Proteobacteria. The role of Helicobacter spp. remains unclear. Recent isolation of Malassezia globosa from PDAC tissue suggest also the mycobiota as a crucial player of tumorigenesis. Based on described molecular mechanisms and interactions between the pancreatic tissue and the immune system this review proposes a model of how the micro- and the mycobial dysbiosis could contribute to tumorigenesis in PDAC.

CONCLUSIONS

The presence of micro- and mycobial dysbiosis in pancreatic tumor tissue opens a fascinating perspective on PDAC oncogenesis. Further studies will pave the way for novel tumor markers and treatment strategies.

Oral-Gut Microbiome Axis in Gastrointestinal Disease and Cancer

It is well-known that microbiota dysbiosis is closely associated with numerous diseases in the human body. The oral cavity and gut are the two largest microbial habitats, playing a major role in microbiome-associated diseases. Even though the oral cavity and gut are continuous regions connected through the gastrointestinal tract, the oral and gut microbiome profiles are well-segregated due to the oral-gut barrier. However, the oral microbiota can translocate to the intestinal mucosa in conditions of the oral-gut barrier dysfunction. Inversely, the gut-to-oral microbial transmission occurs as well in inter- and intrapersonal manners. Recently, it has been reported that oral and gut microbiomes interdependently regulate physiological functions and pathological processes. Oral-to-gut and gut-to-oral microbial transmissions can shape and/or reshape the microbial ecosystem in both habitats, eventually modulating pathogenesis of disease. However, the oral-gut microbial interaction in pathogenesis has been underappreciated to date. Here, we will highlight the oral-gut microbiome crosstalk and its implications in the pathogenesis of the gastrointestinal disease and cancer. Better understanding the role of the oral-gut microbiome axis in pathogenesis will be advantageous for precise diagnosis/prognosis and effective treatment.

Oral–Gut Microbiome Axis in Gastrointestinal Disease and Cancer

It is well-known that microbiota dysbiosis is closely associated with numerous diseases in the human body. The oral cavity and gut are the two largest microbial habitats, playing a major role in microbiome-associated diseases. Even though the oral cavity and gut are continuous regions connected through the gastrointestinal tract, the oral and gut microbiome profiles are well-segregated due to the oral–gut barrier. However, the oral microbiota can translocate to the intestinal mucosa in conditions of the oral–gut barrier dysfunction. Inversely, the gut-to-oral microbial transmission occurs as well in inter- and intrapersonal manners. Recently, it has been reported that oral and gut microbiomes interdependently regulate physiological functions and pathological processes. Oral-to-gut and gut-to-oral microbial transmissions can shape and/or reshape the microbial ecosystem in both habitats, eventually modulating pathogenesis of disease. However, the oral–gut microbial interaction in pathogenesis has been underappreciated to date. Here, we will highlight the oral–gut microbiome crosstalk and its implications in the pathogenesis of the gastrointestinal disease and cancer. Better understanding the role of the oral–gut microbiome axis in pathogenesis will be advantageous for precise diagnosis/prognosis and effective treatment.

Shotgun metagenomics reveals significant gut microbiome features in different grades of acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) has a broad spectrum of severity and is associated with considerable morbidity and mortality. Dysbiosis of gut microbiota may be associated with AP severity.

AIMS

We aimed to evaluate the composition and functional effects of gut microbiota in different grades of AP severity.

METHODS

We carried out shotgun metagenomic sequencing on rectal swab samples from three patients with mild acute pancreatitis (MAP), three with moderately severe acute pancreatitis (MSAP), three with severe acute pancreatitis (SAP) and three normal control persons (NOR). Differences analysis in gut microbiota composition and functional enrichment was performed.

RESULTS

Gut microbiota in AP patients was characterized by decreased species richness. The most representative gut microbiota in mild acute pancreatitis (MAP), moderately severe acute pancreatitis (MSAP), and severe acute pancreatitis (SAP) was Streptococcus, Escherichia-coli, and Enterococcus, respectively. Each of the three AP-associated genera could differentiate AP from healthy control population. Representative pathways associated with the glutathione metabolism, lipopolysaccharide biosynthesis, and amino acid metabolism (valine, leucine and isoleucine degradation) were enriched in MAP, MSAP, and SAP, respectively.

CONCLUSIONS

The study shows a potential association of gut microbiome composition and function to the progression of AP severity.

Branched-chain amino acids protect the liver from cirrhotic injury via suppression of activation of lipopolysaccharide-binding protein, toll-like receptor 4, and signal transducer and activator of transcription 3, as well as Enterococcus faecalis translocation

OBJECTIVES

Branched-chain amino acids (BCAAs) are used as nutritional support and for improving prognosis in liver cirrhosis. Here we investigate the molecular mechanisms of BCAA treatment and liver damage focused on pathways related to lipopolysaccharide-binding protein (LBP).

METHODS

Serum LBP levels were measured in cirrhotic patients and in cirrhotic rats treated with BCAA to examine the correlation between liver function and survival. In cirrhotic rats, liver damage, Enterococcus faecalis translocation, serum capsular polysaccharide, and intestinal tight junction levels were assessed. Damaged HepG2 cells were cultured with BCAA-supplemented, BCAA-deficient, or control amino acid medium, followed by examination of LBP expression.

RESULTS

Serum LBP levels were significantly increased in deceased patients individuals with liver cirrhosis. The survival rate in patients with lower serum LBP (<3.48 μg/mL) was significantly improved. In BCAA-treated rat liver samples, protein expression of LBP, toll-like receptor 4 (TLR4), and phosphorylated signal transduction and activator of transcription 3 (STAT3) were significantly reduced. Also in BCAA-treated rats, intestinal zonula occludens gene expression was increased, whereas hepatic translocation of E. faecalis and serum capsular polysaccharide levels were reduced. In damaged HepG2 cells, lipopolysaccharide-induced elevation of LBP expression was rapidly and strongly repressed in BCAA-enriched medium.

CONCLUSIONS

Serum LBP level is a prognostic biomarker in liver cirrhosis. BCAA treatment reduced translocation of E. faecalis through intestinal tight junction recovery and reduced LBP expression in the liver, which repressed activation of LBP, toll-like receptor 4, and signal transduction and activator of transcription 3. Our findings suggest that BCAA supplementation protects the liver from damage via multiple pathways.

Research Progress of Pancreas-Related Microorganisms and Pancreatic Cancer

Pancreatic cancer is one of the most common digestive system cancers. Early diagnosis is difficult owing to the lack of specific symptoms and reliable biomarkers. The cause of pancreatic cancer remains ambiguous. Smoking, drinking, new-onset diabetes, and chronic pancreatitis have been proven to be associated with the occurrence of pancreatic cancer. In recent years, a large number of studies have clarified that a variety of microorganisms colonized in pancreatic cancer tissues are also closely related to the occurrence and development of pancreatic cancer, and the specific mechanisms include inflammatory induction, immune regulation, metabolism, and microenvironment changes caused by microorganism. The mechanism of action of the pancreatic colonized microbiome in the tumor microenvironment, as well as immunotherapy approaches require further study in order to find more evidence to explain the complex relationship between the pancreatic colonized microbiome and PDAC. Relevant studies targeting the microbiome may provide insight into the mechanisms of PDAC development and progression, improving treatment effectiveness and overall patient prognosis. In this article, we focus on the research relating to the microorganisms colonized in pancreatic cancer tissues, including viruses, bacteria, and fungi. We also highlight the microbial diversity in the occurrence, invasion, metastasis, treatment, and prognosis of pancreatic cancer in order to elucidate its significance in the early diagnosis and new therapeutic treatment of pancreatic cancer, which urgently need to be improved in clinical practice. The elimination or increase in diversity of the pancreatic microbiome is beneficial for prolonging the survival of PDAC patients, improving the response to chemotherapy drugs, and reducing tumor burden. The colonization of microorganisms in the pancreas may become a new hotspot in the diagnosis and treatment of pancreatic cancer.

The Emerging Role of Microbiota and Microbiome in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignant tumors due to the absence of biomarkers for early-stage detection and poor response to therapy. Since mounting evidence supports the role of microbiota composition in tumorigenesis and cancer treatment, the link between microbiome and PDAC has been described. In this review, we summarize the current knowledge regarding the impact of the gut and oral microbiome on the risk of PDAC development. Microenvironment-driven therapy and immune system interactions are also discussed. More importantly, we provide an overview of the clinical trials evaluating the microbiota role in the risk, prognosis, and treatment of patients suffering from PDAC and solid tumors. According to the research findings, immune tolerance might result from the microbiota-derived remodeling of pancreatic tumor microenvironment. Thus, microbiome profiling and targeting represent the potential trend to enhance antitumor immunity and improve the efficacy of PDAC treatment.

Bidirectional and dynamic interaction between the microbiota and therapeutic resistance in pancreatic cancer

Pancreatic ductal adenocarcinoma is one of the most lethal malignancies and is known for its high resistance and low response to treatment. Cancer treatments can reshape the microbiota and in turn, the microbiota influences the therapeutic efficacy by regulating immune response and metabolism. This crosstalk is bidirectional, heterogeneous, and dynamic. In this review, we elaborated on the interactions between the microbiota and therapeutic resistance in pancreatic ductal adenocarcinoma. Regulating the microbiota in pancreatic tumor microenvironment may not only generate direct anti-cancer but also synergistic effects with other treatments, providing new directions in cancer therapy.