Micro- and Mycobiota Dysbiosis in Pancreatic Ductal Adenocarcinoma Development

Characteristics of microbiomes of the saliva, duodenal bulb, and descending portion of superficial nonampullary duodenal epithelial tumors

INTRODUCTION

Nonampullary duodenal epithelial tumors are rare, but their prevalence is increasing. Various gastrointestinal cancers have been associated with microbiomes. We evaluated the characteristics of the salivary and duodenal microbiomes of patients with nonampullary duodenal epithelial tumors.

METHODS

Saliva and biopsy samples from the duodenal bulb and descending portion were obtained from 15 patients with nonampullary duodenal epithelial tumors and 10 controls. Next-generation sequencing was performed to identify bacteria for comparison.

RESULTS

Saliva samples had higher Amplicon Sequence Variants (ASVs) and more observed species than duodenal samples. Saliva samples from patients with nonampullary duodenal epithelial tumor were dominated by Bacteroidetes and Prevotella, whereas Proteobacteria and Neisseria were dominant in the control samples. The relative abundance of bacteria was higher in patients with nonampullary duodenal epithelial tumors. Most bacteria were classified as bacteria of oral origin. Oribacterium and Stomatobaculum were significantly higher in the saliva, duodenal bulb, and descending portion of patients with nonampullary duodenal epithelial tumors.

CONCLUSION

Patients with nonampullary duodenal epithelial tumors had different salivary and duodenal microbiomes than controls. Bacteria types differed between groups at each site, and most bacteria of oral origin were more abundant in patients with nonampullary duodenal epithelial tumors.

IPIAD- an augmentation regimen added to standard treatment of pancreatic ductal adenocarcinoma using already-marketed repurposed drugs irbesartan, pyrimethamine, itraconazole, azithromycin, and dapsone

This short note presents the data and rationale for adding five generic non-oncology drugs from general medical practice to gemcitabine, nab-paclitaxel, a current standard cytotoxic chemotherapy of pancreatic ductal adenocarcinoma. The regimen, called IPIAD, uses an angiotensin receptor blocker (ARB) irbesartan indicated for treating hypertension, an old antimicrobial drug pyrimethamine indicated for treating toxoplasmosis or malaria, an old antifungal drug itraconazole, an old broad spectrum antibiotic azithromycin and an old antibiotic dapsone. In reviewing selected growth driving systems active in pancreatic ductal adenocarcinoma then comparing these with detailed data on ancillary attributes of the IPIAD drugs, one can predict clinical benefit and slowing growth of pancreatic ductal adenocarcinoma by this augmentation regimen.

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.

Intratumoral microbiota: implications for cancer onset, progression, and therapy

Significant advancements have been made in comprehending the interactions between the microbiome and cancer. However, prevailing research predominantly directs its focus toward the gut microbiome, affording limited consideration to the interactions of intratumoral microbiota and tumors. Within the tumor microenvironment (TME), the intratumoral microbiome and its associated products wield regulatory influence, directing the modulation of cancer cell properties and impacting immune system functionality. However, to grasp a more profound insight into the intratumoral microbiota in cancer, further research into its underlying mechanisms is necessary. In this review, we delve into the intricate associations between intratumoral microbiota and cancer, with a specific focus on elucidating the significant contribution of intratumoral microbiota to the onset and advancement of cancer. Notably, we provide a detailed exploration of therapeutic advances facilitated by intratumoral microbiota, offering insights into recent developments in this burgeoning field.

The inflammatory response of human pancreatic cancer samples compared to normal controls

Pancreatic ductal adenocarcinoma (PDAC) is a poor prognosis cancer with an aggressive growth profile that is often diagnosed at late stage and that has few curative or therapeutic options. PDAC growth has been linked to alterations in the pancreas microbiome, which could include the presence of the fungus Malassezia. We used RNA-sequencing to compare 14 matched tumor and normal (tumor adjacent) pancreatic cancer samples and found Malassezia RNA in both the PDAC and normal tissues. Although the presence of Malassezia was not correlated with tumor growth, a set of immune- and inflammatory-related genes were up-regulated in the PDAC compared to the normal samples, suggesting that they are involved in tumor progression. Gene set enrichment analysis suggests that activation of the complement cascade pathway and inflammation could be involved in pro PDAC growth.

A pancreatic adenocarcinoma mimicking hepatoid carcinoma of uncertain histogenesis: A case report and literature review

In rare cases, metastatic adenocarcinomas of different origin may exhibit the features of hepatoid carcinoma (HC), a rare malignant epithelial tumor, most commonly occurring in the ovaries and stomach, as well as in the pancreas and biliary ducts. A case of a 72-year-old female patient who developed a highly aggressive, poorly differentiated pancreatic ductal adenocarcinoma with peritoneal carcinomatosis, demonstrating hepatoid differentiation upon conventional hematoxylin and eosin staining is reported in the present study. The patient presented with severe abdominal pain, and the radiological investigations performed revealed ovarian and hepatic tumor masses and peritoneal lesions, which were surgically removed. The gross examination of the peritoneum and omentum revealed multiple solid, firm, grey-white nodules, diffusely infiltrating the adipose tissue. The microscopic examination revealed a malignant epithelial proliferation, composed of polygonal cells with abundant eosinophilic cytoplasm and irregular, pleomorphic nuclei. Certain cells presented with intracytoplasmic mucus inclusions, raising suspicion of a HC with an uncertain histogenesis. Immunohistochemical staining was performed, and the tumor cells were found to be positive for cytokeratin (CK)7, CK18 and mucin 5AC, whereas negative staining for CK20, caudal-type homeobox transcription factor 2, α-fetoprotein, paired box gene 8, GATA-binding protein 3 and Wilms tumor 1 were documented. Thus, the diagnosis of metastatic pancreatic adenocarcinoma was established. The main aim of the present study was to provide further knowledge concerning poorly differentiated metastatic adenocarcinoma resembling HC, emphasizing the histopathological and immunohistochemical features of these malignant lesions and raising awareness of the diagnostic difficulties that may arise, as well as the importance of the use immunohistochemistry in differentiating carcinomas of uncertain histogenesis.

2bRAD-M reveals the difference in microbial distribution between cancerous and benign ovarian tissues

The development of ovarian cancer is closely related to various factors, such as environmental, genetic and microbiological factors. In previous research, bacteria were identified in human tumors by 16S rRNA sequencing. However, the microbial biomass in tumor tissue is too low and cannot be accurately identified by 16S rRNA sequencing. In our study, we employ 2bRAD sequencing for Microbiome (2bRAD-M), a new sequencing technology capable of accurately characterizing the low biomass microbiome (bacteria, fungi and archaea) at species resolution. Here we surveyed 20 ovarian samples, including 10 ovarian cancer samples and 10 benign ovarian samples. The sequencing results showed that a total of 373 microbial species were identified in both two groups, of which 90 species shared in the two groups. The Meta statistic indicated that Chlamydophila_abortus and CAG-873_sp900550395 were increased in the ovarian cancer tissues, while Lawsonella_clevelandensis_A, Ralstonia_sp001078575, Brevundimonas_aurantiaca, Ralstonia_sp900115545, Ralstonia_pickettii, Corynebacterium_kefirresidentii, Corynebacterium_sp000478175, Brevibacillus_D_fluminis, Ralstonia_sp000620465, and Ralstonia_mannitolilytica were more abundant in the benign ovarian tissues. This is the first use of 2bRAD-M technique to provide an important hint for better understanding of the ovarian cancer microbiome.

The role of the symbiotic microecosystem in cancer: gut microbiota, metabolome, and host immunome

The gut microbiota is not just a simple nutritional symbiosis that parasitizes the host; it is a complex and dynamic ecosystem that coevolves actively with the host and is involved in a variety of biological activities such as circadian rhythm regulation, energy metabolism, and immune response. The development of the immune system and immunological functions are significantly influenced by the interaction between the host and the microbiota. The interactions between gut microbiota and cancer are of a complex nature. The critical role that the gut microbiota plays in tumor occurrence, progression, and treatment is not clear despite the already done research. The development of precision medicine and cancer immunotherapy further emphasizes the importance and significance of the question of how the microbiota takes part in cancer development, progression, and treatment. This review summarizes recent literature on the relationship between the gut microbiome and cancer immunology. The findings suggest the existence of a "symbiotic microecosystem" formed by gut microbiota, metabolome, and host immunome that is fundamental for the pathogenesis analysis and the development of therapeutic strategies for cancer.

Isolation of Malassezia yeasts from dogs with gastrointestinal disease undergoing duodenal endoscopy

OBJECTIVES

To culture Malassezia and other fungi from the duodenum of dogs with gastrointestinal signs undergoing routine endoscopic examination.

MATERIALS AND METHODS

Quantitative microbial culture was performed on duodenal juice aspirated from dogs with suspected enteropathy during routine upper gastrointestinal endoscopy; samples were cultured on Sabouraud's dextrose agar (30, 32 and 37°C) and modified Dixon agar (32°C) for 14 days. Isolates were identified phenotypically and by matrix-assisted laser desorption ionisation-time of flight, and internal transcribed spacer sequencing. Yeast presence was also evaluated by cytological and histopathological examination of smears and biopsy specimens.

RESULTS

Forty-five dogs were recruited with chronic inflammatory enteropathy (n=38), granulomatous colitis (n=2), gastric adenocarcinoma (n=2), duodenal small cell lymphoma (n=1) and idiopathic severe gastrointestinal haemorrhage (n=2). Fungi were cultured from 14 dogs: Malassezia pachydermatis was isolated from eight [chronic inflammatory enteropathy (n=7) (along with Candida albicans n=1); granulomatous colitis (n=1)] and Malassezia sympodialis from another (gastric adenocarcinoma). Five dogs with chronic inflammatory enteropathy yielded other yeasts (C. albicans, Candida glabrata, Kazachstania slooffiae, Kazachstania telluris, Pichia kudriavzevii [syn. C. krusei]). Yeasts were never observed in histopathological specimens. Fluorescent microscopical examination of cytological specimens showed yeast in only one case, from which K. slooffiae was subsequently isolated.

CLINICAL SIGNIFICANCE

Based on a literature search, this is the first report of isolation of M. pachydermatis, M. sympodialis, K. slooffiae and K. telluris from the canine duodenum. Further studies are needed to determine whether these are resident or transient fungi in the canine duodenum and whether their presence has a pathogenic effect on the host.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

The immune response to a fungus in pancreatic cancer samples

Pancreatic ductal adenocarcinoma (PDAC) is a poor prognosis cancer with an .aggressive growth profile that is often diagnosed at late stage and that has few curative or therapeutic options. PDAC growth has been linked to alterations in the pancreas microbiome, which could include the presence of the fungus Malassezia. We used RNA-sequencing to compare 14 paired tumor and normal (tumor adjacent) pancreatic cancer samples and found Malassezia RNA in both the PDAC and normal tissues. Although the presence of Malassezia was not correlated with tumor growth, a set of immune- and inflammatory-related genes were up-regulated in the PDAC compared to the normal samples, suggesting that they are involved in tumor progression. Gene set enrichment analysis suggests that activation of the complement cascade pathway and inflammation could be involved in pro PDAC growth.

Complement and Fungal Dysbiosis as Prognostic Markers and Potential Targets in PDAC Treatment

Pancreatic ductal adenocarcinoma (PDAC) is still hampered by a dismal prognosis. A better understanding of the tumor microenvironment within the pancreas and of the factors affecting its composition is of utmost importance for developing new diagnostic and treatment tools. In this context, the complement system plays a prominent role. Not only has it been shown to shape a T cell-mediated immune response, but it also directly affects proliferation and apoptosis of the tumor cells, influencing angiogenesis, metastatic spread and therapeutic resistance. This makes complement proteins appealing not only as early biomarkers of PDAC development, but also as therapeutic targets. Fungal dysbiosis is currently the new kid on the block in tumorigenesis with cancer-associated mycobiomes extracted from several cancer types. For PDAC, colonization with the yeast Malassezia seems to promote cancer progression, already in precursor lesions. One responsible mechanism appears to be complement activation via the lectin pathway. In the present article, we review the role of the complement system in tumorigenesis, presenting observations that propose it as the missing link between fungal dysbiosis and PDAC development. We also present the results of a small pilot study supporting the crucial interplay between the complement system and Malassezia colonization in PDAC pathogenesis.

Oral mycobiota and pancreatic ductal adenocarcinoma

Early detection of pancreatic ductal adenocarcinoma (PDAC) is essential for survival. Preliminary research demonstrated significant associations between structural alternation of mycobiota and PDAC. In this study, we investigated the associations between oral mycobiota and PDAC. We further explored mycobiota biomarkers for PDAC detection. We enrolled 34 PDAC patients and 35 matched healthy controls from West China hospital in Southwest China. Demographic data, clinical information, and salivary samples were collected. Mycobiota characteristics were defined using Internal Transcribed Spacer (ITS) ribosomal RNA sequencing. We found that the PDAC patients had significant increase in fungal abundance (P < 0.001) and significant decrease in fungal diversity (P < 0.001) in comparison to the healthy controls. A higher abundance of Basidiomycota and Unclassifed_p_Ascomycota was associated with an increased risk of PDAC. With each increase of abundance of g__unclassified_k__Fungi and g__unclassified_p__Ascomycota in PDAC patients, the risk of pancreatic cancer increased by 1.359 odds and 1.260 odds, respectively. Aspergillus (AUC = 0.983, 95% CI 0.951-1.000) and Cladosporium (AUC = 0.969, 95% CI 0.921-1.000) achieved high classification powers to distinguish PDAC patients from the healthy controls. The rapid, inexpensive tests of ITS1 sequencing of mycobiota and PCR detection of potential fungal biomarkers make it promising for the clinical practice to use oral microbes for PDAC early detection and prevention. Results of our study provide evidence that salivary mycobiota may provide insights into cancer risk, prevention, and detection.

Challenges in precision medicine in pancreatic cancer: A focus in cancer stem cells and microbiota

Pancreatic cancer adenocarcinoma (PDAC) is a lethal disease, with the lowest 5-years survival rate of all cancers due to late diagnosis. Despite the advance and success of precision oncology in gastrointestinal cancers, the frequency of molecular-informed therapy decisions in PDAC is currently neglectable. The reasons for this dismal situation are mainly the absence of effective early diagnostic biomarkers and therapy resistance. PDAC cancer stem cells (PDAC-SC), which are regarded as essential for tumor initiation, relapse and drug resistance, are highly dependent on their niche i.e. microanatomical structures of the tumor microenvironment. There is an altered microbiome in PDAC patients embedded within the highly desmoplastic tumor microenvironment, which is known to determine therapeutic responses and affecting survival in PDAC patients. We consider that understanding the communication network that exists between the microbiome and the PDAC-SC niche by co-culture of patient-derived organoids (PDOs) with TME microbiota would recapitulate the complexity of PDAC paving the way towards a precision oncology treatment-response prediction.

Identification of Malassezia globosa as a Gastric Fungus Associated with PD-L1 Expression and Overall Survival of Patients with Gastric Cancer

BACKGROUND

Microbiotas affected the prognosis of cancer patients by regulating programmed death ligand-1 (PD-L1) expression. However, the relationship between gastric fungi and PD-L1 expression is still unclear in gastric cancer (GC). We aimed at exploring the association of gastric fungi with PD-L1 expression and overall survival in GC.

METHODS

A total of 61 GC patients were divided into the two groups based on the PD-L1 combined positive scores (CPS). Fungal profiling was performed by internal transcribed spacer rDNA sequencing, and the survival analyses were performed by Kaplan-Meier curves.

RESULTS

We observed a taxonomic difference of fungi between the PD-L1-High (CPS ≥ 10) and PD-L1-Low group (CPS < 10) by principal coordinates analysis (PCoA) (P = 0.014 for Bray-Curtis and P = 0.042 for Jaccard). Malassezia had a higher abundance in the PD-L1-High group compared to the PD-L1-Low group (P = 0.045). Malassezia globosa elevated significantly in the PD-L1-High group. GC patients with PD-L1 low expression and low abundance of Malassezia globosa had a longer overall survival (OS) than others (P = 0.047). Malassezia globosa was associated with PD-L1 expression (Odds Ratio = 3.509, 95% Confidence Interval: 1.056-11.656, P = 0.040). Malassezia globosa was associated with the tumor size (P = 0.031) and PD-L1 status (P = 0.024). GC patients with a high abundance of Malassezia globosa had shorter OS than others (P = 0.028). Malassezia globosa was an independent factor (Hazard Ratio = 3.080, 95% Confidence Interval: 1.140-8.323, P = 0.027) for OS after adjusting for tumor stage. Malassezia globosa was figured out to be associated with- fatty acid and lipid biosynthesis and degradation via LIPASYN pathway. Conclusions. Malassezia globosa was identified as a PD-L1 expression-associated gastric fungus and associated with OS of GC patients, which calls for more studies to further explore its potential in PD-L1/PD-1 targeted immunotherapy.

Association of oral microbiome and pancreatic cancer: a systematic review and meta-analysis

BACKGROUND

Oral microbiota reported to be associated with pancreatic diseases, including pancreatic cancer. However, the association of oral microbiome and pancreatic cancer has not been reviewed systematically.

OBJECTIVES

To systematically investigate the association between the oral microbiome and pancreatic cancer risk.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES AND METHODS

Systemic searches were conducted using PubMed, Medline, Cochrane Library, and Embase databases without any language restriction from conception to August 29, 2020. The studies that evaluated the association of oral microbiome and pancreatic cancer risk were included in this meta-analysis.

RESULTS

The six included studies encompassed a total of 863 pancreatic cancer cases and 906 controls. Four studies reported the overall oral microbiome in pancreatic cancer cases. A total of 12-17 species/clusters were correlated with pancreatic cancer. Three studies reported the odds ratios (ORs) or relative abundance of several oral microbiomes pieces/clusters, and the majority were associated with pancreatic cancer.

CONCLUSIONS

Overall, this study supports the hypothesis of associations of variations of patients' oral microbiota to pancreatic cancer. Nonetheless, due to all included studies were conducted in USA or Europe, additional original studies and meta-analysis particular studies from other countries are essential for an in-depth investigation into the role of oral bacteria in pancreatic cancer.

Fusobacterium nucleatum and Malignant Tumors of the Digestive Tract: A Mechanistic Overview

Fusobacterium nucleatum (F. nucleatum) is an oral anaerobe that plays a role in several oral diseases. However, F. nucleatum is also found in other tissues of the digestive tract, and several studies have recently reported that the level of F. nucleatum is significantly elevated in malignant tumors of the digestive tract. F. nucleatum is proposed as one of the risk factors in the initiation and progression of digestive tract malignant tumors. In this review, we summarize recent reports on F. nucleatum and its role in digestive tract cancers and evaluate the mechanisms underlying the action of F. nucleatum in digestive tract cancers.

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.

Connecting the Human Microbiome and Pancreatic Cancer

Pancreatic cancer is a deadly disease that is increasing in incidence throughout the world. There are no clear causal factors associated with the incidence of pancreatic cancer; however, some correlation to smoking, diabetes and alcohol has been described. Recently, a few studies have linked the human microbiome (oral and gastrointestinal tract) to pancreatic cancer development. A perturbed microbiome has been shown to alter normal cells while promoting cancer-related processes such as increased cell signaling, immune system evasion and invasion. In this article, we will review in detail the alterations within the gut and oral microbiome that have been linked to pancreatic cancer and explore the ability of other microbiomes, such as the lung and skin microbiome, to contribute to disease development. Understanding ways to identify a perturbed microbiome can result in advancements in pancreatic cancer research and allow for prevention, earlier detection and alternative treatment strategies for patients.