PI3K-CCL2-CCR2-MDSCs axis: A potential pathway for tumor Clostridia-promoted CD 8+ T lymphocyte infiltration in bile tract cancers

BACKGROUND

Most patients with resected bile tract cancers (BTCs) survive for less than 5 years; however, some achieve better prognosis. The tumor microbiome can improve survival by regulating the tumor immune microenvironment. However, whether the tumor microbiome promotes immune cell infiltration in BTCs is unknown. This study aimed to determine the association between CD8+ T lymphocyte infiltration and the tumor microbiome in patients with resected BTCs.

METHODS

Archived formalin-fixed paraffin-embedded tumor specimens were collected from patients with resected BTCs and analyzed using 16S rRNA gene sequencing to identify that prognosis-related and significantly differentially enriched taxa. Gene ontology (GO) analysis of the differentially enriched taxa was used to assess how CD8+ T lymphocyte infiltration is affected by the tumor microbiome of BTCs.

RESULTS

We enrolled 32 patients with resected BTCs. The high CD8+ lymphocyte-infiltration (CD8hi) group had four significantly enriched taxa, and in the low CD8+ lymphocyte-infiltration (CD8low) group comprised one significantly enriched taxon. Patients with higher Clostridia abundance (enriched in the CD8hi group) experienced longer overall survival than those with lower abundance. The enrichment of Clostridia in the CD8hi group corresponded with lower CCL2 expression and downregulation of phosphatidylinositol 3-kinase activity, which might decrease myeloid-derived suppressor cell recruitment to the tumor milieu, thus increasing CD8+ lymphocyte infiltration in BTCs.

CONCLUSIONS

The tumor microbiome is related to CD8+ T lymphocyte infiltration in patients with resected BTCs. The relationship between tumor Clostridia and high infiltration of CD8+ T lymphocytes might reflect decreased recruitment of myeloid-derived suppressor cells via the PI3K-CCL2-CCR2 axis.

Association of Chronic Opisthorchis Infestation and Microbiota Alteration on Tumorigenesis in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a common hepatobiliary cancer in East and Southeast Asia. The data of microbiota contribution in CCA are still unclear. Current available reports have demonstrated that an Opisthorchis viverrini (OV) infection leads to dysbiosis in the bile duct. An increase in the commensal bacteria Helicobacter spp. in OV-infected CCA patients is associated with bile duct inflammation, severity of bile duct fibrosis, and cholangiocyte proliferation. In addition, secondary bile acids, major microbial metabolites, can mediate cholangiocyte inflammation and proliferation in the liver. A range of samples from CCA patients (stool, bile, and tumor) showed different degrees of dysbiosis. The evidence from these samples suggests that OV infection is associated with alterations in microbiota and could potentially have a role in CCA. In this comprehensive review, reports from in vitro, in vivo, and clinical studies that demonstrate possible links between OV infection, microbiota, and CCA pathogenesis are summarized and discussed. Understanding these associations may pave ways for novel potential adjunct intervention in gut microbiota in CCA patients.

Association between small intestinal bacterial overgrowth and toll-like receptor 4 in patients with pancreatic carcinoma and cholangiocarcinoma

BACKGROUND/AIMS

Multiple factors have been linked to pathogenesis of pancreatic cancer and cholangiocarcinoma. Until now, few studies have investigated the role of small intestinal bacterial overgrowth (SIBO) and toll-like receptor 4 (TLR-4) signaling in these diseases. This study aimed to examine the relationship between the prevalence of SIBO and the TLR-4 expression in patients with pancreatic carcinoma and cholangiocarcinoma.

MATERIALS AND METHODS

A total of 90 human subjects suffering from pancreatic carcinoma (n=30), cholangiocarcinoma (n=30), and healthy controls (n=30) were enrolled in the study. A glucose hydrogen breath test (GHBT) was used to evaluate SIBO. The TLR4 protein expression was measured by immunohistochemistry (IHC).

RESULTS

The positive rate of SIBO was 63.3% in the pancreatic cancer group and 46.7% in patients with cholangiocarcinoma, which was significantly greater than 13.3% in the healthy control group (p<0.05). An IHC analysis revealed that the TLR-4 protein expression in the SIBO-positive pancreatic carcinoma patients was significantly higher than that in the SIBO-negative patients (p<0.05), and the same result was in the cholangiocarcinoma subjects. In addition, a correlation analysis identified the positive relationship between the prevalence of SIBO and the TLR-4 protein expression in pancreatic carcinoma (r=0.489), and the same result was in the cholangiocarcinoma subjects.

CONCLUSION

Our findings indicate a high prevalence of SIBO in pancreatic carcinoma and cholangiocarcinoma, and SIBO displays a positive correlation with the TLR-4 expression, suggesting that SIBO could be a risk factor for the pathogenesis of pancreatic carcinoma and cholangiocarcinoma, in which the TLR4 signaling may be involved.

Opisthorchiasis-Induced Cholangiocarcinoma: How Innate Immunity May Cause Cancer

Innate, inflammatory responses towards persistent Opisthorchis viverrini (OV) infection are likely to contribute to the development of cholangiocarcinoma (CCA), a liver cancer that is rare in the West but prevalent in Greater Mekong Subregion countries in Southeast Asia. Infection results in the infiltration of innate immune cells into the bile ducts and subsequent activation of inflammatory immune responses that fail to clear OV but instead may damage local tissues within the bile ducts. Not all patients infected with OV develop CCA, and so tumourigenesis may be dependent on multiple factors including the magnitude of the inflammatory response that is activated in infected individuals. The purpose of this review is to summarize how innate immune responses may promote tumourigenesis following OV infection and if such responses can be used to predict CCA onset in OV-infected individuals. It also hypothesizes on the role that Helicobacterspp., which are associated with liver fluke infections, may play in activation of the innate the immune system to promote tissue damage and persistent inflammation leading to CCA.

Infection with Helicobacter bilis but not Helicobacter hepaticus was Associated with Extrahepatic Cholangiocarcinoma

BACKGROUND AND AIMS

The biliary tract cancer or cholangiocarcinoma (CCA) represents the sixth leading cause of gastrointestinal tumors in the Western world, and mortality varies across the world, with regions such as Chile, Thailand, Japan, and northeastern India presenting the highest rates. CCA may develop in the bile duct, gallbladder, or ampulla of Vater; and risk factors include obesity, parity, genetic background, geographical and environmental factors. Inflammation induced by bacterial infections might play a role in the pathogenesis of CCA. In this work, we investigated whether there is an association between extrahepatic cholangiocarcinoma (ECCA) and infection with S. typhi, H. hepaticus, or H. bilis in a Mexican population.

METHODS

A total of 194 patients were included and divided into 91 patients with benign biliary pathology (controls) and 103 with ECCA (cases). Tumor samples were taken during endoscopic retrograde cholangiopancreatography by biliary brushing, followed by DNA extraction and PCR testing for infections.

RESULTS

We found that 44/103 cases were positive for H. bilis, compared with 19/91 controls (p = 0.002; OR 2.83, 95% CI 1.49-5.32), and when analyzed by sub-site, H. bilis infection was significantly more associated with cancer in the common bile duct (p = 0.0005; OR 3.56, 95% CI 1.77-7.17). In contrast, H. hepaticus infection was not different between cases (17/103) and controls (13/91) (p = 0.82; OR 1.19, 95% CI 0.54-2.60). None of the samples were positive for S. typhi infection.

CONCLUSION

In conclusion, infection with H. bilis but neither H. Hepaticus nor S. typhi was significantly associated with ECCA, particularly with tumors located in the common bile duct.

A microRNA profile associated with Opisthorchis viverrini-induced cholangiocarcinoma in tissue and plasma

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive tumor of the bile duct, and a significant public health problem in East Asia, where it is associated with infection by the parasite Opisthorchis viverrini. ICC is often detected at an advanced stage and with a poor prognosis, making a biomarker for early detection a priority.

METHODS

We have comprehensively profiled miRNA expression levels in ICC tumor tissue using small RNA-Seq and validated these profiles using quantitative PCR on matched plasma samples.

RESULTS

Distinct miRNA profiles were associated with increasing histological differentiation of ICC tumor tissue. We also observed that histologically normal tissue adjacent to ICC tumor displayed miRNA expression profiles more similar to tumor than liver tissue from healthy donors. In plasma samples, an eight-miRNA signature associated with ICC, regardless of the degree of histological differentiation of its matched tissue, forming the basis of a circulating miRNA-based biomarker for ICC.

CONCLUSIONS

The association of unique miRNA profiles with different ICC subtypes suggests the involvement of specific miRNAs during ICC tumor progression. In plasma, an eight-miRNA signature associated with ICC could form the foundation of an accessible (plasma-based) miRNA-based biomarker for the early detection of ICC.

Helicobacter species infection may be associated with cholangiocarcinoma: a meta-analysis

OBJECTIVE

Since the discovery of Helicobacter species in human biliary system, the association between Helicobacter species infection and cholangiocarcinoma is under debate. This meta-analysis aims to explore this issue.

METHODS

Literature search was carried out to identify all eligible articles. We performed overall meta-analysis of all included studies and subgroup analysis based on regional distribution. Subgroup analysis in the light of detection methods and specimens was also conducted.

RESULTS

Ten case-control studies were included. Overall meta-analysis favoured a significant association between Helicobacter species infection and cholangiocarcinoma (cumulative OR 8.88, 95% CI 3.67-21.49). Subgroup analysis based on geographic distribution indicated that Helicobacter species infection may serve as a risk factor not only in a region with high cholangiocarcinoma incidence (Asia, OR 6.68, 95% CI 2.29-19.49) but also in low incidence region (Europe, OR 14.90, 95% CI 4.79-46.35). The other subgroup analysis showed that PCR was the most effective and efficient method to detect Helicobacter species in surgically resected tissue and bile. There was significant heterogeneity among studies and obvious publication bias.

CONCLUSION

Our meta-analysis supports the possible association between Helicobacter species infection and cholangiocarcinoma. Further investigations are required to clarify the role of Helicobacter species in this malignancy.

Promoter hypermethylation is a major event of hMLH1 gene inactivation in liver fluke related cholangiocarcinoma

Cholangiocarcinoma is a crucial health problem in Northeast Thailand where liver fluke infection is endemic. However, molecular genetic and epigenetic mechanisms involved in carcinogenesis of this cancer remain unclear. We attempted to study genetic and epigenetic alterations of hMLH1 gene in 65 intrahepatic cholangiocarcinoma using polymerase chain reaction (PCR) based microsatellite marker D3S1611 and methylation-specific PCR, respectively. Of 65 cases, 29 (44.6%) showed hypermethylation of hMLH1 promoter. Loss of heterozygosity (LOH) of hMLH1 was detected in 12 of 51 informative cases (23.5%). Five out of 29 (17.2%) methylated cases demonstrated LOH. Aberrant methylation of hMLH1 promoter was significantly associated with poorly differentiated type (P=0.013). Our study suggests that both genetic and epigenetic mechanisms cause the inactivation of hMLH1 where epigenetic is a major event resulting in mismatch repair deficiency and contributing to carcinogenesis of liver fluke related cholangiocarcinoma. Since, gene silencing by methylation is an early event in carcinogenesis, promoter hypermethylation of hMLH1 may be a molecular targeted therapy and prevention of liver fluke related cholangiocarcinoma.

Comparative analysis of Helicobacter DNAs and biliary pathology in patients with and without hepatobiliary cancer

Several Helicobacter species have recently been isolated from the bile and hepatobiliary systems of murine species, and are well recognized as a pathogen of the hepatobiliary disorder. This study was planned to investigate whether Helicobacter species possess a causative potential for human hepatobiliary disease, especially for hepatobiliary carcinogenesis. Bile and hepatobiliary tissue samples from 19 patients with hepatobiliary cancer and 19 patients with benign biliary diseases were subjected to polymerase chain reaction analyses for the detection of Helicobacter DNAs. Using a proliferating cell nuclear antigen (PCNA) staining technique, we also investigated the biliary epithelial cell kinetics with special reference to the presence of Helicobacter DNAs in the hepatobiliary system. We found that Helicobacter DNAs were positive in 10 (52.6%) of the 19 patients with hepatobiliary cancer. The incidence was significantly higher than that (15.7%) in the benign cases (P = 0.03). The PCNA labeling index in the biliary epithelium in Helicobacter DNA-positive patients was statistically higher than that in Helicobacter DNA-negative ones, regardless of whether the patient was suffering from hepatobiliary cancer and/or biliary inflammation. A close correlation between the presence of Helicobacter DNAs and an elevation of the PCNA labeling index in the biliary epithelium was demonstrated by multiple regression analysis. Our findings suggest that Helicobacter species may play a role in the pathogenesis of hepatobiliary cancer through an acceleration of biliary cell kinetics.

[Intestinal bacterial translocation in patients with biliary tract diseases]

To determine whether intestinal bacterial translocation occurs in man, the authors cultured the tissues of mesenteric lymph nodes(MLNs), bile, portal and peripheral venous blood obtained prior to and during operation in 35 patients with biliary diseases. No positive peritoneal swab, portal blood and peripheral blood culture were shown. Thirteen of 20 patients with biliary obstruction (65%) had bacteria in their MLNs, while no positive MLN culture was found in 12 patients without biliary obstruction. The most common bacteria recovered from the MLNs were Gram-negative enteric bacilli. Thus, it is considered that extrahepatic biliary obstruction may induce intestinal bacterial translocation in man.

Hepatobiliary inflammation, neoplasia, and argyrophilic bacteria in a ferret colony

Hepatobiliary disease was diagnosed in eight of 34 genetically unrelated cohabitating pet ferrets (Mustela putorios furo) during a 7-year period. The eight ferrets ranged in age from 5 to 8 years and exhibited chronic cholangiohepatitis coupled with cellular proliferation ranging from hyperplasia to frank neoplasia. Spiral-shaped argyrophilic bacteria were demonstrated in livers of three ferrets, including two with carcinoma. Sequence analysis of a 400-base pair polymerase chain reaction product amplified from DNA derived from fecal bacteria from one ferret demonstrated 98% and 97% similarity to Helicobacter cholecystus and Helicobacter sp. strain 266-1 , respectively. The clustering of severe hepatic disease in these cohabitating ferroes suggests a possible infectious etiology. The role of Helicobacter species and other bacteria in hepatitis and/or neoplasia in ferrets requires further study.

Detection of Helicobacter species in the liver of patients with and without primary liver carcinoma

BACKGROUND

Several studies have shown the presence of Helicobacter species in the human biliary tract and in the intestinal tract of animals. In this study, the presence of Helicobacter species in liver samples from patients with primary hepatic carcinomas was evaluated.

METHODS

Sixteen liver specimens were studied (8 from patients with primary liver carcinoma and 8 from patients without primary liver carcinoma). Histology with standard stains, culture, and polymerase chain reaction (PCR) amplification using two sets of primers located in the 16S ribosomal DNA (rDNA) were used to detect the presence of bacteria. Amplified products were sequenced to determine the genus and species of the bacteria. A search for other genes that were specific for Helicobacter pylori also was carried out by PCR.

RESULTS

PCR performed with the 16S rDNA primers revealed the presence of bacteria from the genus Helicobacter in all of the liver specimens from patients with primary liver carcinoma (eight of eight patients) and in one specimen from a patient without primary liver carcinoma (one of eight patients). When the nucleotide sequence of > 80% of the 16S rDNA was determined, the closest similarity was with the 16S rDNA from H. pylori in eight patients. In 1 patient sample from which only 398 nucleotides were sequenced, the closest match was Helicobacter felis.

CONCLUSIONS

The results presented in this study indicate that Helicobacter species can be present in the liver of patients with primary hepatic carcinoma, but their eventual role in the carcinogenesis process, although it is plausible, remains to be proven. Based on sequence similarity, it seems that Helicobacter species that are related closely to H. pylori but are distinct from it have been found.

Detection of Helicobacter DNA in bile from bile duct diseases

Several species of Helicobacter colonize the hepatobiliary tract of animals and cause hepatobiliary diseases. The aim of this study is to investigate Helicobacter found in the biliary tract diseases of humans. Thirty-two bile samples (15 from bile duct cancer, 6 from pancreatic head cancer, and 11 from intrahepatic duct stone) were obtained by percutaneous transhepatic biliary drainage. Polymerase chain reaction analysis using Helicobacter specific urease A gene and 16S rRNA primers, bile pH measurement, and Helicobacter culture were performed. Helicobacter DNA was detected in 37.5%, and 31.3% by PCR with ureA gene, and 16S rRNA, respectively. The bile pH was not related to the presence of Helicobacter. The cultures were not successful. In conclusion, Helicobacter can be detected in the bile of patients with bile duct diseases. The possibility of pathogenesis of biliary tract diseases in humans by these organisms will be further investigated.

[Expression of five different antigens of HBV in human intrahepatic cholangiocarcinoma and cholangiohepatocarcinoma]

Surgical specimens of 20 cases of human intrahepatic cholangiocarcinoma (n = 12) and cholangiohepatocarcinoma (n = 8) were studied immunohistochemically by ABC technique for HBxAg, pre-S1 and pre-S2 and by PAP method for HBsAg and HBcAg. The neighboring liver tissues with chronic hepatitis or cirrhosis surrounding the tumor were also examined in 19 cases. Of the cancerous tissues, 15 were positive for HBxAg (75%), 8 positive for pre-S1 and pre-S2 (40%), respectively and 2 for HBsAg (10%). Sixteen of 19 liver tissues surrounding the tumor were also positive for HBxAg (84.2%), 9 for pre-S1 and pre-S2 each (47.4%), 6 for HBsAg and HBcAg each (31.6%). The results suggest that a close relationship exists between cholangiocarcinoma and cholangiohepatocarcinoma and hepatitis B virus infection. The HBxAg might play an important role in the pathogenesis of cholangiocarcinoma.

Bile duct carcinoma in Egypt: possible etiological factors

Contrary to an old belief, bile duct carcinoma is not a rare disorder in Egypt. Among 730 patients referred for an ERCP examination, twenty-nine consecutive patients were diagnosed as having bile duct carcinoma. The cause of this type of carcinoma remains unknown. In the present study, only seven of the 29 (24.1%) with bile duct carcinoma patients had associated gallstones. In order to investigate the possible association between typhoid carrier state and bile duct carcinoma, stool cultures were performed for Salmonella typhi and Salmonella paratyphi A and B. Nine out of 23 patients (39.1%) with bile duct carcinoma, 17 out of 50 (34%) with calcular obstructive jaundice, and 1 out of 50 (2%) healthy individuals proved to be salmonella carriers. Statistical analysis of the results confirmed the presence of a significant association between chronic fecal thyphoid carrier state and bile duct carcinoma, while that between calcular obstructive jaundice and bile duct carcinoma was not significant. In conclusion, there might be an association between chronic fecal typhoid carrier state and bile duct carcinoma.

[Comprehensive study of percutaneous transhepatic aspiration bile culture and cholangiography]

In this study, the results of transhepatically aspirated bile culture, and cholangiography done in 220 cases with biliary tract diseases were presented. Aerobes and anaerobes were found in 76.4% and 64.7% of all samples respectively. Patients with partial common bile duct obstruction from stricture and choledocholithiasis had markedly higher positive cultures than that with simple gallbladder stones and complete common duct obstruction secondary to carcinomas of the pancreas or ampulla. Bile culture from patients with symptomatic cholangitis was much more often positive than those with asymptomatic cholangitis. It was also found that patients with positive bile cultures were more prone to after-PTC acute cholangitis. This study suggested that bile organisms are mainly from the gut, bile organisms and bile duct obstruction are two major causes of acute cholangitis, abrupt elevation of bile pressure during PTC procedure was also a causing factor of acute cholangitis. The authors advocate the comprehensive and prophylactic use of antibiotics both effective to aerobes and anaerobes in the treatment of biliary tract infection.

Mucoepidermoid carcinoma of the bile duct

Three patients with mucoepidermoid carcinoma of the bile duct are described. In two patients the tumor arose from the common hepatic duct. Mucoepidermoid carcinoma of the extrahepatic bile duct has not been previously reported. The clinical features and pathologic behavior of this rare type of tumor are similar to the usual biliary adenocarcinoma. The coexistence of Clonorchis sinensis infestation and primary pyogenic cholangitis raises the possibility of an etiologic association.

[Bacteriological studies on the bile in different conditions of surgical interest]

A bacteriological study was carried out on bile taken, during the course of surgery, from 235 patients suffering from a wide variety of diseases, both benign and malignant, concerning the bile ways. The investigation, initially directed to the aerobic bile flora, was afterwards extended to include germs growing in strict anaerobiosis. The highest incidence of bactibilia was found in repeat operations for post-operative stenosis of the hepatocholedochus, followed by neoplasias of the gall-bladder or main bile duct, and calculosis of the gall-bladder. For germs growing in compulsory anaerobiosis the responses to the cultural test were all negative, while in two cases microaerophilic streptococci were isolated. Finally the results of the antibiograms made on the isolated microbial species are reported.