Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine

Growing evidence suggests that microbes can influence the efficacy of cancer therapies. By studying colon cancer models, we found that bacteria can metabolize the chemotherapeutic drug gemcitabine (2',2'-difluorodeoxycytidine) into its inactive form, 2',2'-difluorodeoxyuridine. Metabolism was dependent on the expression of a long isoform of the bacterial enzyme cytidine deaminase (CDDL), seen primarily in Gammaproteobacteria. In a colon cancer mouse model, gemcitabine resistance was induced by intratumor Gammaproteobacteria, dependent on bacterial CDDL expression, and abrogated by cotreatment with the antibiotic ciprofloxacin. Gemcitabine is commonly used to treat pancreatic ductal adenocarcinoma (PDAC), and we hypothesized that intratumor bacteria might contribute to drug resistance of these tumors. Consistent with this possibility, we found that of the 113 human PDACs that were tested, 86 (76%) were positive for bacteria, mainly Gammaproteobacteria.

The Pancreatic Cancer Microbiome Promotes Oncogenesis by Induction of Innate and Adaptive Immune Suppression

We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous pancreas compared with gut. Ablation of the microbiome protects against preinvasive and invasive pancreatic ductal adenocarcinoma (PDA), whereas transfer of bacteria from PDA-bearing hosts, but not controls, reverses tumor protection. Bacterial ablation was associated with immunogenic reprogramming of the PDA tumor microenvironment, including a reduction in myeloid-derived suppressor cells and an increase in M1 macrophage differentiation, promoting TH1 differentiation of CD4+ T cells and CD8+ T-cell activation. Bacterial ablation also enabled efficacy for checkpoint-targeted immunotherapy by upregulating PD-1 expression. Mechanistically, the PDA microbiome generated a tolerogenic immune program by differentially activating select Toll-like receptors in monocytic cells. These data suggest that endogenous microbiota promote the crippling immune-suppression characteristic of PDA and that the microbiome has potential as a therapeutic target in the modulation of disease progression.Significance: We found that a distinct and abundant microbiome drives suppressive monocytic cellular differentiation in pancreatic cancer via selective Toll-like receptor ligation leading to T-cell anergy. Targeting the microbiome protects against oncogenesis, reverses intratumoral immune tolerance, and enables efficacy for checkpoint-based immunotherapy. These data have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic. Cancer Discov; 8(4); 403-16. ©2018 AACR.See related commentary by Riquelme et al., p. 386This article is highlighted in the In This Issue feature, p. 371.

Pancreatic neoplasia induced by SV40 T-antigen expression in acinar cells of transgenic mice

Three lines of transgenic mice were produced that develop pancreatic neoplasms as a consequence of expression of an elastase I-SV40 T-antigen fusion gene in the acinar cells. A developmental analysis suggests at least a two-stage process in the ontogeny of this disease. The first stage is a T antigen-induced, preneoplastic state characterized by a progression from hyperplasia to dysplasia of the exocrine pancreas, by an increased percentage of tetraploid cells, and by an arrest in acinar cell differentiation. The second stage is characterized by the formation of tumor nodules that appear to be monoclonal, because they have discrete aneuploid DNA contents. The cells within the nodules as compared to normal pancreatic tissue have less total RNA by a factor of 5, less pancreas-specific messenger RNA by a factor of about 50, and increased levels of T-antigen messenger RNA. A tumor cell line has been derived that retains both pancreatic and neoplastic properties.

Microbiota-derived 3-IAA influences chemotherapy efficacy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second most deadly cancer by 2040, owing to the high incidence of metastatic disease and limited responses to treatment1,2. Less than half of all patients respond to the primary treatment for PDAC, chemotherapy3,4, and genetic alterations alone cannot explain this5. Diet is an environmental factor that can influence the response to therapies, but its role in PDAC is unclear. Here, using shotgun metagenomic sequencing and metabolomic screening, we show that the microbiota-derived tryptophan metabolite indole-3-acetic acid (3-IAA) is enriched in patients who respond to treatment. Faecal microbiota transplantation, short-term dietary manipulation of tryptophan and oral 3-IAA administration increase the efficacy of chemotherapy in humanized gnotobiotic mouse models of PDAC. Using a combination of loss- and gain-of-function experiments, we show that the efficacy of 3-IAA and chemotherapy is licensed by neutrophil-derived myeloperoxidase. Myeloperoxidase oxidizes 3-IAA, which in combination with chemotherapy induces a downregulation of the reactive oxygen species (ROS)-degrading enzymes glutathione peroxidase 3 and glutathione peroxidase 7. All of this results in the accumulation of ROS and the downregulation of autophagy in cancer cells, which compromises their metabolic fitness and, ultimately, their proliferation. In humans, we observed a significant correlation between the levels of 3-IAA and the efficacy of therapy in two independent PDAC cohorts. In summary, we identify a microbiota-derived metabolite that has clinical implications in the treatment of PDAC, and provide a motivation for considering nutritional interventions during the treatment of patients with cancer.

Isolation of Clostridium in human infections: evaluation of 114 cases

One hundred fifty-two strains of Clostridium were isolated from 144 patients over a 14-month-peroid. These included 23 recognized species and 23 strains that were unclassified. Soft tissues or abscesses yielded 84 strains of Clostridium. Intraabdominal sites predominated, but clostridia were recovered from empyema, carcinoma, frostbite with gas gangrene, muscle abscess, aortic graft, and brain abscess. Blood cultures yielded 65 strains of Clostridium from 49 patients, representing 0.3% of 16,314 blood cultures (or 2.6% of 2,168 positive cultures). Clostridium perfringens was most common in blood, accounting for 37 isolates (57%). Clostridial bacteremia was often unrelated to the clinical setting and was found in alcoholics with aspiration or Streptococcus pneumoniae pneumonia, pulmonary tuberculosis, empyema, meningococcemia, and infantile gastroenteritis. In 20 of the 49 patients (41%), aerobic or other anaerobic bacteria were cultured concurrently from the blood. Thus, clostridial bacteremia should be interpreted with caution since there may be little correlation with the patient's clinical condition.

The Microbiomes of Pancreatic and Duodenum Tissue Overlap and Are Highly Subject Specific but Differ between Pancreatic Cancer and Noncancer Subjects

BACKGROUND

In mice, bacteria from the mouth can translocate to the pancreas and impact pancreatic cancer progression. In humans, oral bacteria associated with periodontal disease have been linked to pancreatic cancer risk. It is not known if DNA bacterial profiles in the pancreas and duodenum are similar within individuals.

METHODS

Tissue samples were obtained from 50 subjects with pancreatic cancer or other conditions requiring foregut surgery at the Rhode Island Hospital (RIH), and from 34 organs obtained from the National Disease Research Interchange. 16S rRNA gene sequencing was performed on 189 tissue samples (pancreatic duct, duodenum, pancreas), 57 swabs (bile duct, jejunum, stomach), and 12 stool samples.

RESULTS

Pancreatic tissue samples from both sources (RIH and National Disease Research Interchange) had diverse bacterial DNA, including taxa typically identified in the oral cavity. Bacterial DNA across different sites in the pancreas and duodenum were highly subject specific in both cancer and noncancer subjects. Presence of genus Lactobacillus was significantly higher in noncancer subjects compared with cancer subjects and the relative abundance of Fusobacterium spp., previously associated with colorectal cancer, was higher in cancer subjects compared with noncancer subjects.

CONCLUSIONS

Bacterial DNA profiles in the pancreas were similar to those in the duodenum tissue of the same subjects, regardless of disease state, suggesting that bacteria may be migrating from the gut into the pancreas. Whether bacteria play a causal role in human pancreatic cancer needs to be further examined.

IMPACT

Identifying bacterial taxa that differ in cancer patients can provide new leads on etiologically relevant bacteria.

Pancreatic cancer, inflammation, and microbiome

Pancreatic cancer is one of the most lethal cancers worldwide. No effective screening methods exist, and available treatment modalities do not effectively treat the disease. Inflammatory conditions such as pancreatitis represent a well-known risk factor for pancreatic cancer development. Yet only in the past 2 decades has pancreatic cancer been recognized as an inflammation-driven cancer, and the precise mechanisms underlying the pathogenic role of inflammation are beginning to be explored in detail. A substantial amount of preclinical and clinical evidence suggests that bacteria are likely to influence this process by activating immune receptors and perpetuating cancer-associated inflammation. The recent explosion of investigations of the human microbiome have highlighted how perturbations of commensal bacterial populations can promote inflammation and promote disease processes, including carcinogenesis. The elucidation of the interplay between inflammation and microbiome in the context of pancreatic carcinogenesis will provide novel targets for intervention to prevent and treat pancreatic cancer more efficiently. Further studies toward this direction are urgently needed.

Helicobacter pylori seropositivity as a risk factor for pancreatic cancer

BACKGROUND

Pancreatic cancer is among the most fatal cancers worldwide and one for which few preventable risk factors have been established. Gastric carriage of Helicobacter pylori, particularly cytotoxin-associated gene-A-positive (CagA+) strains, is known to be a risk factor for peptic ulcer disease and gastric cancer and may have a similar etiologic relationship with pancreatic cancer.

METHODS

We investigated the association of H. pylori carriage and exocrine pancreatic cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29 133 male Finnish smokers aged 50-69 years at baseline. Case subjects (n = 121) were matched on date of baseline serum collection, study center, age, trial intervention, and completion of the dietary questionnaire to 226 control subjects who were alive at the time the matching case subject was diagnosed and who remained free of cancer, during up to 10 years of follow-up. Levels of immunoglobulin G antibodies to H. pylori whole-cell and CagA+ antigens from stored baseline serum were measured by enzyme-linked immunosorbent assay. Smoking-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of conditional logistic regression. Statistical tests were two-sided.

RESULTS

Seroprevalence of H. pylori was 82% and 73% among case and control subjects, respectively. Compared with seronegative subjects, those with H. pylori or CagA+ strains were at statistically significantly elevated risk of pancreatic cancer (OR = 1.87 [95% CI = 1.05 to 3.34]; OR = 2.01 [95% CI = 1.09 to 3.70], respectively).

CONCLUSIONS

Our findings support a possible role for H. pylori carriage in the development of exocrine pancreatic cancer.

Association between Helicobacter pylori infection and pancreatic cancer

PURPOSE

In order to determine whether infection with Helicobacter pylori might be associated with pancreatic adenocarcinoma, we performed a study to compare the H. pylori seroprevalence rate between patients with pancreatic carcinoma and matched control subjects.

PATIENTS AND METHODS

Blood samples from 92 patients with histologically confirmed diagnosis of pancreatic adenocarcinoma admitted to our hospital between January 1994 and July 1995 were analyzed for the presence of IgG antibodies against H. pylori by a commercially available enzyme-linked immunosorbent assay. Thirty patients with gastric cancer, 35 patients with colorectal cancer, and 27 healthy volunteers served as controls. In addition to these serological analyses, tumor specimens from 20 patients with pancreatic adenocarcinoma were microscopically investigated for the presence of H. pylori.

RESULTS

65% of pancreatic cancer patients and 69% of those with gastric cancer were found to be seropositive, while only 45% of the other controls tested positive. Statistical analysis revealed no difference in seropositivity between the cohort of patients suffering from pancreatic and gastric cancer. The rate of seropositivity was more prominent, however, in pancreatic cancer patients when compared with those suffering from colorectal cancer combined with normal controls (p = 0.035), with an odds ratio of 2.1 (1.1-4.1). Microscopic evaluation of human pancreatic cancer specimens showed no evidence for the presence of H. pylori.

CONCLUSION

Our data suggest an association between H. pylori infection and pancreatic cancer. Despite demonstration of a positive relationship and its physiological plausibility, larger prospective studies are needed to confirm our preliminary findings and to assess H. pylori as a potential carcinogenic risk factor.

Association of BK virus with human brain tumors and tumors of pancreatic islets

BK virus (BKV) DNA was detected by Southern blot hybridization in 19 out of 74 (25.6%) human brain tumors and in 4 out of 9 (44.4%) human tumors of pancreatic islets. BKV DNA was free, in an episomal state and generally in a low copy number (0.2 to 2 genome equivalents per cell). Only occasional tumors contained 10 to 20 genome copies per cell. Viral DNA sequences integrated into cellular DNA were not detected. A number of tumors expressed BKV-specific RNA and T antigen. By transfection of total tumor DNA into human embryonic fibroblasts, viruses with the biological and antigenic properties of BKV were rescued from 6 brain tumors and from 2 tumors of pancreatic islets. Restriction endonuclease mapping of the genomes of the rescued viruses showed that they differ from wild-type BKV. They are all similar to each other and to BKV-IR, a virus previously rescued from a human tumor of pancreatic islets, suggesting the possible association of a BKV variant with specific types of human neoplasms. The significance of the relationship of these BKV variants to human tumors and their possible etiologic role in human oncogenesis are discussed.

Helicobacter species ribosomal DNA in the pancreas, stomach and duodenum of pancreatic cancer patients

AIM: To determine whether gastric and enteric Helicobacter species are associated with pancreatic cancer.

METHODS: Patients with exocrine pancreatic cancer (n = 40), neuroendocrine cancer (n = 14), multiple endocrine neoplasia type 1 (n = 8), and chronic pancreatitis (n = 5) were studied. Other benign pancreatic diseases (n = 10) and specimens of normal pancreas (n = 7) were included as controls. Pancreatic tissue specimens were analyzed by Helicobacter-specific PCR-assay and products were characterized by denaturing gradient electrophoresis and DNA-sequencing. From a subset of the pancreatic cancer patients, gastric and/or duodenal tissue as well as gallbladder and ductus choledochus tissue were analyzed. Gallbladder and choledochus samples were included as controls. Stomach and duodenum samples were investigated to analyze whether a gastric helicobacter might disseminate to the pancreas in pancreatic cancer patients. Pancreatic specimens were analyzed by Bacteroides-specific PCR for detecting the translocation of indigenous gut microbes to the diseased pancreas.

RESULTS: Helicobacter DNA was detected in pancreas (tumor and/or surrounding tissue) of 75% of patients with exocrine cancer, 57% of patients with neuroendocrine cancer, 38% of patients with multiple endocrine neoplasia, and 60% of patients with chronic pancreatitis. All samples from other benign pancreatic diseases and normal pancreas were negative. Thirty-three percent of the patients were helicobacter-positive in gastroduodenal specimens. Surprisingly, H. bilis was identified in 60% of the positive gastroduodenal samples. All gallbladder and ductus choledochus specimens were negative for helicobacter. Bacteroides PCR-assay was negative for all pancreatic samples.

CONCLUSION: Helicobacter DNA commonly detected in pancreatic cancer suggests a possible role of the emerging pathogens in the development of chronic pancreatitis and pancreatic cancer.

Tumor microbiome contributes to an aggressive phenotype in the basal-like subtype of pancreatic cancer

Despite the uniform mortality in pancreatic adenocarcinoma (PDAC), clinical disease heterogeneity exists with limited genomic differences. A highly aggressive tumor subtype termed 'basal-like' was identified to show worse outcomes and higher inflammatory responses. Here, we focus on the microbial effect in PDAC progression and present a comprehensive analysis of the tumor microbiome in different PDAC subtypes with resectable tumors using metagenomic sequencing. We found distinctive microbial communities in basal-like tumors and identified an increasing abundance of Acinetobacter, Pseudomonas and Sphingopyxis to be highly associated with carcinogenesis. Functional characterization of microbial genes suggested the potential to induce pathogen-related inflammation. Host-microbiota interplay analysis provided new insights into the tumorigenic role of specific microbiome compositions and demonstrated the influence of host genetics in shaping the tumor microbiome. Taken together, these findings indicated that the tumor microbiome is closely related to PDAC oncogenesis and the induction of inflammation. Additionally, our data revealed the microbial basis of PDAC heterogeneity and proved the predictive value of the microbiome, which will contribute to the intervention and treatment of disease.

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

(Aim) Bacterial infection underlies the pathogenesis of many human diseases, including acute and chronic inflammation. Here, we investigated a possible role for bacterial infection in the progression of chronic pancreatitis. (Materials and Methods) Pancreatic juice was obtained from patients with pancreatic cancer (n = 20) or duodenal cancer/bile duct cancer (n = 16) and subjected to PCR using universal primers for the bacterial 16S ribosomal RNA gene. Bacterial species were identified by PCR using bile samples from four pancreatic cancer patients. PCR products were subcloned into T-vectors, and the sequences were then analyzed. Immunohistochemical and serologic analyses for Enterococcus faecalis infection were performed on a large cohort of healthy volunteers and patients with chronic pancreatitis or pancreatic cancer and on mice with caerulein-induced chronic pancreatitis. The effect of E. faecalis antigens on cytokine secretion by pancreatic cancer cells was also investigated. (Results) We found that 29 of 36 pancreatic juice samples were positive for bacterial DNA. Enterococcus and Enterobacter species were detected primarily in bile, which is thought to be a pathway for bacterial infection of the pancreas. Enterococcus faecalis was also detected in pancreatic tissue from chronic pancreatitis and pancreatic cancer patients; antibodies to E. faecalis capsular polysaccharide were elevated in serum from chronic pancreatitis patients. Enterococcus-specific antibodies and pancreatic tissue-associated E. faecalis were detected in mice with caerulein-induced chronic pancreatitis. Addition of Enterococcus lipoteichoic acid and heat-killed bacteria induced expression of pro-fibrotic cytokines by pancreatic cancer cells in vitro. (Conclusion) Infection with E. faecalis may be involved in chronic pancreatitis progression, ultimately leading to development of pancreatic cancer.

The oral microbiota in patients with pancreatic cancer, patients with IPMNs, and controls: a pilot study

PURPOSE

Poor oral health appears to be a risk factor for pancreatic cancer, possibly implicating the oral microbiota. In this pilot study, we evaluated the characteristics of the oral microbiota in patients with pancreatic ductal adenocarcinoma (PDAC), intraductal papillary mucinous neoplasms (IPMN), and healthy controls.

METHODS

Forty newly diagnosed PDAC patients, 39 IPMN patients, and 58 controls, excluding current smokers and users of antibiotics, provided saliva samples. Common oral bacterial species were comprehensively surveyed by sequencing of the 16S rRNA microbial genes. We obtained measures of diversity and the mean relative proportions of individual taxa. We explored the degree to which these measures differed according to respondent characteristics based on individual interviews.

RESULTS

PDAC cases did not differ in diversity measures from either controls or IPMN cases. PDAC cases had higher mean relative proportions of Firmicutes and related taxa, while controls had higher mean relative proportions of Proteobacteria and related taxa. Results were generally similar when comparing PDAC to IPMN cases. Among IPMNs and controls combined, younger individuals had higher levels of several taxa within the Proteobacteria. The only other variable consistently related to mean relative proportions was mouthwash use, with taxa within Firmicutes more common among users.

CONCLUSIONS

While there were no differences in diversity of the oral microbiota among these groups, there were differences in the mean relative proportions of some taxa. Characteristics of the oral microbiota are not associated with most measures of oral health.

Dual-Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor-Resident Intracellular Bacteria

The limited drug penetration and robust bacteria-mediated drug inactivation in pancreatic cancer result in the failure of chemotherapy. To fight against these issues, a dual-cascade responsive nanoparticle (sNP@G/IR) that can sequentially trigger deep penetration, killing of intratumor bacteria, and controlled release of chemo-drug, is reported. sNP@G/IR consists of a hyaluronic acid (HA) shell and glutathione (GSH)-responsive polymer-core (NP@G/IR), that encapsulates gemcitabine (Gem) and photothermal agent (IR1048). The polymer core, as an antibiotic alternative, is tailored to exert optimal antibacterial activity and selectivity. sNP@G/IR actively homes in on the tumor due to the CD44 targeting of the HA shell, which is subsequently degraded by the hyaluronidase in the extracellular matrix. The resultant NP@G/IR in decreased size and reversed charge facilitates deep tumor penetration. After cellular endocytosis, the exposed guanidine on NP@G/IR kills intracellular bacteria through disrupting cell membranes. Intracellular GSH further triggers the controlled release of the cargo. Thus, the protected Gem eventually induces cell apoptosis. Under laser irradiation, the hyperthermia of IR1048 helps further elimination of tumors and bacteria. Moreover, sNP@G/IR activates immune response, thereby reinforcing anticancer capacity. Therefore, this dual-cascade responsive sNP@G/IR eliminates tumor-resident intracellular bacteria and augments drug delivery efficacy, providing a new avenue for improving cancer therapy.

Helicobacter pylori infection and development of pancreatic cancer

BACKGROUND

Infection with Helicobacter pylori is an established risk factor for gastric cancer. Results from two studies suggest that it may also be a risk factor for pancreatic cancer.

METHODS

We conducted a nested case control study among 128,992 adult subscribers to the Kaiser Permanente Medical Care Program who had been enrolled in a multiphasic health checkup from 1964 to 1969. Serum collected during the checkup was maintained frozen, and subjects were followed for cancer. Cases consisted of 104 randomly selected subjects among 507 who developed pancreatic cancer in the cohort. Controls consisted of 262 pancreatic cancer-free subjects from a pool of 730 controls previously tested for studies conducted on this cohort. Controls were individually matched to cases on age, gender, race, site, and date of multiphasic health checkup. Control sera were compared with cases for antibodies to H. pylori and the CagA protein. The effects of smoking, alcohol consumption, obesity, and years of education were also investigated.

RESULTS

Neither H. pylori [odds ratio (OR), 0.85; 95% confidence interval (95% CI), 0.49-1.48] nor its CagA protein (OR, 0.96; 95% CI, 0.48-1.92) was associated with subsequent development of pancreatic cancer. Smoking (OR, 2.09; 95% CI, 1.17-3.74) and greater number of years of education (OR, 2.13; 95% CI, 1.23-3.69) were risk factors for pancreatic cancer, whereas alcohol consumption and obesity were not.

CONCLUSION

Our results suggest that H. pylori infection is not associated with development of pancreatic cancer.

Helicobacter pylori seropositivities and risk of pancreatic carcinoma

BACKGROUND

Pathophysiologic actions of Helicobacter pylori colonization on gastric acidity have been hypothesized to modulate the effect of pancreatic carcinogens, through CagA-negative organism strain type, hyperchlorhydria and increased risk of pancreatic cancer, or CagA-positive strain, hypochlorhydria and decreased risk of pancreatic cancer. We aimed to determine H. pylori strain-specific associations with pancreatic cancer in a population in which colonization by CagA-positive strains is common.

METHODS

We carried out a large population-based case-control study of pancreatic carcinoma in Shanghai, China. Venipuncture specimens were obtained from a representative sample of 761 case patients and 794 randomly selected control subjects matched by category of age and gender. Antibody seropositivity for H. pylori and its virulence protein CagA were determined by commercial enzyme-linked immunosorbent IgG assays.

RESULTS

Compared with individuals seronegative for both H. pylori and CagA, decreased pancreas-cancer risk was seen for CagA seropositivity [adjusted OR, 0.68; 95% confidence interval (CI), 0.54-0.84], whereas some increased risk was suggested for CagA-negative H. pylori seropositivity (OR, 1.28; 95% CI, 0.76-2.13). No risk interactions were observed between CagA seropositivity and gender, cigarette smoking, or age-21 body mass index.

CONCLUSIONS

Similar to what has been seen in animal models, our results provide suggestive evidence in humans for the involvement of gastric acidity, through its bidirectional modification according to colonization by H. pylori CagA strain type, in the risk of pancreatic carcinoma.

IMPACT

H. pylori colonization may have diverse effects on cancer risk, depending on the organism strain type as well as on the particular cancer site.

Microbiome and pancreatic cancer: A comprehensive topic review of literature

AIM

To review microbiome alterations associated with pancreatic cancer, its potential utility in diagnostics, risk assessment, and influence on disease outcomes.

METHODS

A comprehensive literature review was conducted by all-inclusive topic review from PubMed, MEDLINE, and Web of Science. The last search was performed in October 2016.

RESULTS

Diverse microbiome alterations exist among several body sites including oral, gut, and pancreatic tissue, in patients with pancreatic cancer compared to healthy populations.

CONCLUSION

Pilot study successes in non-invasive screening strategies warrant further investigation for future translational application in early diagnostics and to learn modifiable risk factors relevant to disease prevention. Pre-clinical investigations exist in other tumor types that suggest microbiome manipulation provides opportunity to favorably transform cancer response to existing treatment protocols and improve survival.

Association of helicobacter pylori infection and chronic atrophic gastritis with risk of colonic, pancreatic and gastric cancer: A ten-year follow-up of the ESTHER cohort study

OBJECTIVES

To assess the association of H. pylori and chronic atrophic gastritis (AG) with colonic, pancreatic and gastric cancer in a population-based prospective cohort.

METHODS

Serum antibodies against H. pylori in general and specific to cytotoxin-associated gene A (CagA), as well as serum pepsinogen I and II were analyzed in 9,506 men and women, aged 50-75 years in a cohort study from Saarland, Germany. Incident cases of colonic, pancreatic and gastric cancer were ascertained by record linkage with data from the Saarland Cancer Registry.

RESULTS

During an average follow-up of 10.6 years, 108 colonic, 46 pancreatic and 27 gastric incident cancers were recorded. There was no association between H. pylori infection and colonic cancer (HR = 1.07; 95% CI 0.73-1.56) or pancreatic cancer (HR = 1.32; 0.73-2.39), regardless of either CagA seropositivity or AG status. In contrast, CagA+ infection was associated with a strongly increased risk of gastric cancer, especially non-cardia gastric cancer, and this association was particularly pronounced in the presence of AG. Compared to people without AG and without CagA+ infection, people with both risk factors had a significantly increased risk of non-cardia gastric cancer (HR = 32.4; 7.6-137.6).

CONCLUSIONS

This large cohort study did not observe an association of H. pylori infection or AG with colonic or pancreatic cancer, but underlines that the vast majority of non-cardia gastric cancers arise from AG and infection with CagA+ H. pylori strains.

Episomal DNA of a BK virus variant in a human insulinoma

BK virus (BKV) DNA was detected by blot hybridization in a human adenoma of pancreatic islets from patient I.R. BKV DNA was free, and no evidence was found of viral sequences integrated into cellular DNA. Virus was rescued by transfection of human embryonic fibroblasts with tumor DNA. The DNA from rescued virus (BKV-IR) was different from wild-type BKV DNA by restriction endonuclease mapping. The genome of BKV-IR is 235 base pairs (bp) shorter than the genome of wild-type BKV. This alteration originates from a deletion of approximately 300 bp involving HindIII fragments B and D, and an insertion of 70 bp in the region of HindIII fragment C. Transformation of hamster kidney cells was induced by total tumor DNA as well as by BKV-IR and BKV-IR DNA. No antibodies to BKV tumor (T) antigen were detected in the patient's serum by immunofluorescence. The significance of episomal BKV DNA in a human tumor is discussed.

Oral microbial community composition is associated with pancreatic cancer: A case-control study in Iran

BACKGROUND

Oral microbiota may be related to pancreatic cancer risk because periodontal disease, a condition linked to multiple specific microbes, has been associated with increased risk of pancreatic cancer. We evaluated the association between oral microbiota and pancreatic cancer in Iran.

METHODS

A total of 273 pancreatic adenocarcinoma cases and 285 controls recruited from tertiary hospitals and a specialty clinic in Tehran, Iran provided saliva samples and filled out a questionnaire regarding demographics and lifestyle characteristics. DNA was extracted from saliva and the V4 region of the 16S rRNA gene was PCR amplified and sequenced on the MiSeq. The sequencing data were processed using the DADA2 plugin in QIIME 2 and taxonomy was assigned against the Human Oral Microbiome Database. Logistic regression and MiRKAT models were calculated with adjustment for potential confounders.

RESULTS

No association was observed for alpha diversity with an average of 91.11 (standard deviation [SD] 2.59) sequence variants for cases and 89.42 (SD 2.58) for controls. However, there was evidence for an association between beta diversity and case status. The association between the Bray-Curtis dissimilarity and pancreatic cancer was particularly strong with a MiRKAT P-value of .000142 and specific principal coordinate vectors had strong associations with cancer risk. Several specific taxa were also associated with case status after adjustment for multiple comparisons.

CONCLUSION

The overall microbial community appeared to differ between pancreatic cancer cases and controls. Whether these reflect differences evident before development of pancreatic cancer will need to be evaluated in prospective studies.

Molecular and biological properties of BK virus-IR, a BK virus variant isolated from a human tumor

We describe the molecular and biological properties of BK virus (BKV)-IR, a new BKV variant isolated from a human tumor of pancreatic islets. BKV-IR bears a 253-base-pair (bp) deletion and an 80-bp insertion in the early region of the genome. The deletion abolishes the expression of small-t antigen. The inserted sequences, grouped in four clusters, produce rearrangements in the first and second enhancer elements. They are bound by 12-bp direct repeats and could form a 217-base stem-loop structure suggestive of an insertion sequence. As compared with wild-type BKV, BKV-IR transformed hamster cells with a reduced efficiency and induced ependymomas in hamsters at a lower frequency and with a longer latency period. Tumors induced by BKV-IR, however, showed features of higher malignancy. The possible role of the insertion sequence-like element in transformation by BKV-IR is discussed.

Seropositivity to Helicobacter pylori and risk of pancreatic cancer

Helicobacter pylori (H. pylori) seropositivity has been inconsistently associated with pancreatic cancer. We, therefore, investigated the association between H. pylori seropositivity and pancreatic cancer in a case-control study nested within Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) cohort of Finnish male smokers. Pancreatic cancer cases (n = 353) and control subjects (n = 353) were matched on date of baseline serum collection, age at randomization, and follow-up time (up to 23.9 years). We used a multiplex serology assay to determine the sero-status of antibodies against 15 H. pylori-specific antigens in fasting serum samples. Conditional logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI). Neither targeted H. pylori antigens in serum nor the combination of all was associated with development of pancreatic cancer (combination of all: OR, 0.85; 95% CI, 0.49-1.49). Our results suggest that H. pylori is not a risk factor for pancreatic cancer.

Roles of Commensal Microbiota in Pancreas Homeostasis and Pancreatic Pathologies

The pancreas plays a central role in metabolism, allowing ingested food to be converted and used as fuel by the cells throughout the body. On the other hand, the pancreas may be affected by devastating diseases, such as pancreatitis, pancreatic adenocarcinoma (PAC), and diabetes mellitus (DM), which generally results in a wide metabolic imbalance. The causes for the development and progression of these diseases are still controversial; therefore it is essential to better understand the underlying mechanisms which compromise the pancreatic homeostasis. The interest in the study of the commensal microbiome increased extensively in recent years, when many discoveries have illustrated its central role in both human physiology and maintenance of homeostasis. Further understanding of the involvement of the microbiome during the development of pathological conditions is critical for the improvement of new diagnostic and therapeutic approaches. In the present review, we discuss recent findings on the behavior and functions played by the microbiota in major pancreatic diseases and provide further insights into its potential roles in the maintenance of pancreatic steady-state activities.

Isolation of Escherichia fergusonii from four different sites in a patient with pancreatic carcinoma and cholangiosepsis

Escherichia fergusonii was isolated from a 69-year-old male with pancreatic carcinoma and cholangiosepsis from gallbladder fluid, three blood cultures, feces, and a superficial wound of the abdomen. Biochemical reactions, antimicrobial susceptibility patterns, susceptibility to polyvalent phage 0-1, and rRNA gene restriction analysis suggested that the four strains were of clonal origin. Our data indicate that E. fergusonii possesses a pathogenic potential in humans.