Expression of p53 and PCNA in cholangiocarcinoma and primary sclerosing cholangitis

SERPINE1: Role in Cholangiocarcinoma Progression and a Therapeutic Target in the Desmoplastic Microenvironment

A heterogenous population of inflammatory elements, other immune and nonimmune cells and cancer-associated fibroblasts (CAFs) are evident in solid malignancies where they coexist with the growing tumor mass. In highly desmoplastic malignancies, CAFs are the prominent mesenchymal cell type in the tumor microenvironment (TME), where their presence and abundance signal a poor prognosis. CAFs play a major role in the progression of various cancers by remodeling the supporting stroma into a dense, fibrotic matrix while secreting factors that promote the maintenance of cancer stem-like characteristics, tumor cell survival, aggressive growth and metastasis and reduced sensitivity to chemotherapeutics. Tumors with high stromal fibrotic signatures are more likely to be associated with drug resistance and eventual relapse. Identifying the molecular underpinnings for such multidirectional crosstalk among the various normal and neoplastic cell types in the TME may provide new targets and novel opportunities for therapeutic intervention. This review highlights recent concepts regarding the complexity of CAF biology in cholangiocarcinoma, a highly desmoplastic cancer. The discussion focuses on CAF heterogeneity, functionality in drug resistance, contributions to a progressively fibrotic tumor stroma, the involved signaling pathways and the participating genes.

EIF3B stabilizes PCNA by counteracting SYVN1-mediated ubiquitination to serve as a promotor in cholangiocarcinoma

Cholangiocarcinoma, a prevalent hepatic malignancy, exhibits a progressively rising incidence. While Eukaryotic translation initiation factor 3 subunit B (EIF3B) has been implicated in the occurrence and development of various cancers, its specific roles in cholangiocarcinoma remain unexplored. Immunohistochemical (IHC) analysis was employed to detect EIF3B/PCNA expression in cholangiocarcinoma. Cells were manipulated using short hairpin RNA (shRNA)-mediated lentiviruses or overexpression plasmids. Statistical significance was assessed using the Student's t-test and one-way ANOVA, with P < 0.05 considered statistically significant. EIF3B exhibited robust expression in cholangiocarcinoma, demonstrating a significant correlation with the pathological grade of cholangiocarcinoma patients. Furthermore, modulation of EIF3B expression, either depletion or elevation, demonstrated the ability to inhibit or enhance cholangiocarcinoma cell survival and migration in vitro. Mechanistically, we identified Proliferating Cell Nuclear Antigen (PCNA) as a downstream gene of EIF3B, driving cholangiocarcinoma. EIF3B stabilized PCNA by inhibiting PCNA ubiquitination, a process mediated by E3 ligase SYVN1. Similar to EIF3B, PCNA levels were also abundant in cholangiocarcinoma, and knocking down PCNA impeded cholangiocarcinoma development. Intriguingly, silencing PCNA attenuated the promotion induced by EIF3B overexpression. Furthermore, the elevated P21 protein level in shEIF3B RBE cells was partially attenuated after UC2288 (P21 signaling pathway inhibitor) treatment. Our findings underscored the potential of EIF3B as a therapeutic target for cholangiocarcinoma. Unraveling its functions holds promise for the development of more specific and effective targeted therapy strategies.

Knockout of liver fluke granulin, Ov-grn-1, impedes malignant transformation during chronic infection with Opisthorchis viverrini

Infection with the food-borne liver fluke Opisthorchis viverrini is the principal risk factor for cholangiocarcinoma (CCA) in the Mekong Basin countries of Thailand, Lao PDR, Vietnam, Myanmar and Cambodia. Using a novel model of CCA, involving infection with gene-edited liver flukes in the hamster during concurrent exposure to dietary nitrosamine, we explored the role of the fluke granulin-like growth factor Ov-GRN-1 in malignancy. We derived RNA-guided gene knockout flukes (ΔOv-grn-1) using CRISPR/Cas9/gRNA materials delivered by electroporation. Genome sequencing confirmed programmed Cas9-catalyzed mutations of the targeted genes, which was accompanied by rapid depletion of transcripts and the proteins they encode. Gene-edited parasites colonized the biliary tract of hamsters and developed into adult flukes. However, less hepatobiliary tract disease manifested during chronic infection with ΔOv-grn-1 worms in comparison to hamsters infected with control gene-edited and mock-edited parasites. Specifically, immuno- and colorimetric-histochemical analysis of livers revealed markedly less periductal fibrosis surrounding the flukes and less fibrosis globally within the hepatobiliary tract during infection with ΔOv-grn-1 genotype worms, minimal biliary epithelial cell proliferation, and significantly fewer mutations of TP53 in biliary epithelial cells. Moreover, fewer hamsters developed high-grade CCA compared to controls. The clinically relevant, pathophysiological phenotype of the hepatobiliary tract confirmed a role for this secreted growth factor in malignancy and morbidity during opisthorchiasis.

Molecular Diagnostics in the Neoplasms of the Pancreas, Liver, Gallbladder, and Extrahepatic Biliary Tract: 2018 Update

Pancreatic neoplasms, including ductal adenocarcinoma, solid pseudopapillary neoplasm, pancreatic endocrine neoplasms, acinar cell carcinoma, and pancreatoblastoma, are associated with different genetic abnormalities. Hepatic adenomas with beta-catenin exon 3 mutation are associated with a high risk of malignancy. Hepatic adenoma with arginosuccinate synthetase 1 expression or sonic hedgehog mutations are associated with a risk of bleeding. Hepatocellular carcinoma and choangiocarcinoma display heterogeneity at both morphologic and molecular levels Cholangiocellular carcinoma is most commonly associated with IDH 1/2 mutations.

Progress in diagnosis and surgical treatment of perihilar cholangiocarcinoma

Cholangiocarcinomas are heterogeneous biliary tract tumors that cause devastating disease. Perihilar cholangiocarcinoma (PHC) is the most common type of biliary tract cancer and are associated with a high mortality. Diagnoses of PHC depend on the results of its clinical presentation, serum biomarkers and imaging techniques. Pre-operative managements including pre-operative biliary drainage (PBD) and portal vein embolization (PVE) could reduce mortality. The best chance of long-term survival and potential cure is surgical resection with negative surgical margin. Lymph node metastasis over N2 nodes precludes long-term survival. The benefit of concomitant vascular resection remains uncertain. Liver transplantation combined with neoadjuvant chemotherapy with radiotherapy is a promising option in highly selected patients with unresectable tumors. Herein, an overview is provided of developments in diagnosis, peri-operative management and surgical treatment among patients with PHCs.

mRNA expression of CDH3, IGF2BP3, and BIRC5 in biliary brush cytology specimens is a useful adjunctive tool of cytology for the diagnosis of malignant biliary stricture

Although advances have been made in diagnostic tools, the distinction between malignant and benign biliary strictures still remains challenging. Intraductal brush cytology is a convenient and safe method that is used for the diagnosis of biliary stricture, but, low sensitivity limits its usefulness. This study aimed to demonstrate the usefulness of mRNA expression levels of target genes in brush cytology specimens combined with cytology for the diagnosis of malignant biliary stricture. Immunohistochemistry for cadherin 3 (CDH3), p53, insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3), homeobox B7 (HOXB7), and baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5) was performed in 4 benign and 4 malignant bile duct tissues. Through endoscopic or interventional radiologic procedures, brush cytology specimens were prospectively obtained in 21 and 35 paitents with biliary strictures. In the brush cytology specimens, the mRNA expressions levels of 5 genes were determined by real-time polymerase chain reaction. Immunohistochemistry for CDH3, p53, IGF2BP3, HOXB7, and BIRC5 all showed positive staining in malignant tissues in contrast to benign tissues, which were negative. In the brush cytology specimens, the mRNA expression levels of CDH3, IGF2BP3, HOXB7, and BIRC5 were significantly higher in cases of malignant biliary stricture compared with cases of benign stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.001). The receiver-operating characteristic curves of these 4 mRNAs demonstrated that mRNA expression levels are useful for the prediction of malignant biliary stricture (P = 0.006, P < 0.001, P < 0.001, and P = 0.002). The sensitivity and specificity, respectively, for malignant biliary stricture were 57.1% and 100% for cytology, 57.1% and 64.3% for CDH3, 76.2% and 100% for IGF2BP3, 71.4% and 57.1% for HOXB7, and 76.2% and 64.3% for BIRC5. When cytology was combined with the mRNA levels of CDH3, IGF2BP3, or BIRC5, the sensitivity for malignant biliary stricture improved to 90.5%. The measurement of the mRNA expression levels of CDH3, IGF2BP3, and BIRC5 by real-time polymerase chain reaction combined with cytology was useful for the differentiation of malignant and benign biliary strictures in brush cytology specimens.

Retinoid X receptor α enhances human cholangiocarcinoma growth through simultaneous activation of Wnt/β-catenin and nuclear factor-κB pathways

Retinoid X receptor α (RXRα) plays important roles in the malignancy of several cancers such as human prostate tumor, breast cancer, and thyroid tumor. However, its exact functions and molecular mechanisms in cholangiocarcinoma (CCA), a chemoresistant carcinoma with poor prognosis, remain unclear. In this study we found that RXRα was frequently overexpressed in human CCA tissues and CCA cell lines. Downregulation of RXRα led to decreased expression of mitosis‐promoting factors including cyclin D1and cyclin E, and the proliferating cell nuclear antigen, as well as increased expression of cell cycle inhibitor p21, resulting in inhibition of CCA cell proliferation. Furthermore, RXRα knockdown attenuated the expression of cyclin D1 through suppression of Wnt/β‐catenin signaling. Retinoid X receptor α upregulated proliferating cell nuclear antigen expression through nuclear factor‐κB (NF‐κB) pathways, paralleled with downregulation of p21. Thus, the Wnt/β‐catenin and NF‐κB pathways account for the inhibition of CCA cell growth induced by RXRα downregulation. Retinoid X receptor α plays an important role in proliferation of CCA through simultaneous activation of Wnt/β‐catenin and NF‐κB pathways, indicating that RXRα might serve as a potential molecular target for CCA treatment.

Perioperative Management of Hilar Cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma is the most common primary tumor of the biliary tract although it accounts for only 2 % of all human malignancies. We herein review hilar cholangiocarcinoma including its risk factors, the main classification systems for tumors, current surgical management of the disease, and the role chemotherapy and liver transplantation may play in selected patients.

METHODS

We performed a comprehensive literature search using PubMed, Medline, and the Cochrane library for the period 1980-2015 using the following MeSH terms: "hilar cholangiocarcinoma", "biliary cancer", and "cholangiocarcinoma". Only recent studies that were published in English and in peer reviewed journals were included.

FINDINGS

Hilar cholangiocarcinoma is a disease of advanced age with an unclear etiology, most frequently found in Southeast Asia and relatively rare in Western countries. The best chance of long-term survival and potential cure is surgical resection with negative surgical margins, but many patients are unresectable due to locally advanced or metastatic disease at diagnosis. As a result of recent efforts, new methods of management have been identified for these patients, including preoperative portal vein embolism and biliary drainage, neoadjuvant chemotherapy with subsequent transplantation, and chemoradiation therapy.

CONCLUSION

Current management of hilar cholangiocarcinoma depends on extent of the tumor at presentation and includes surgical resection, liver transplantation, portal vein embolization, and chemoradiation therapy. Our understanding of hilar cholangiocarcinoma has improved in recent years and further research offers hope to improve the outcome in patients with these rare tumors.

Oncogenic activity of retinoic acid receptor γ is exhibited through activation of the Akt/NF-κB and Wnt/β-catenin pathways in cholangiocarcinoma

Aberrant expression and function of retinoic acid receptor γ (RARγ) are often involved in the progression of several cancers. However, the role of RARγ in cholangiocarcinoma (CCA), chemoresistant bile duct carcinoma with a poor prognosis, remains unclear. In the present study, we found that RARγ was frequently overexpressed in human CCA specimens. Its overexpression was associated with poor differentiation, lymph node metastasis, high serum carbohydrate antigen 19-9 level, and poor prognosis of CCA. Downregulation of RARγ reduced CCA cell proliferation, migration, invasion, and colony formation ability in vitro and tumorigenic potential in nude mice. RARγ knockdown resulted in upregulation of cell cycle inhibitor P21, as well as downregulation of cyclin D1, proliferating cell nuclear antigen, and matrix metallopeptidase 9, in parallel with suppression of the Akt/NF-κB pathway. Furthermore, overexpression of RARγ contributed to the multidrug chemoresistance of CCA cells, at least in part due to upregulation of P glycoprotein via activation of the Wnt/β-catenin pathway. Molecular mechanism studies revealed that RARγ interacted with β-catenin and led to β-catenin nuclear translocation. Taken together, our results suggested that RARγ plays an important role in the proliferation, metastasis, and chemoresistance of CCA through simultaneous activation of the Akt/NF-κB and Wnt/β-catenin pathways, serving as a potential molecular target for CCA treatment.

Oncogenic activity of retinoic acid receptor γ is exhibited through activation of the Akt/NF-κB and Wnt/β-catenin pathways in cholangiocarcinoma

Aberrant expression and function of retinoic acid receptor γ (RARγ) are often involved in the progression of several cancers. However, the role of RARγ in cholangiocarcinoma (CCA), chemoresistant bile duct carcinoma with a poor prognosis, remains unclear. In the present study, we found that RARγ was frequently overexpressed in human CCA specimens. Its overexpression was associated with poor differentiation, lymph node metastasis, high serum carbohydrate antigen 19-9 level, and poor prognosis of CCA. Downregulation of RARγ reduced CCA cell proliferation, migration, invasion, and colony formation ability in vitro and tumorigenic potential in nude mice. RARγ knockdown resulted in upregulation of cell cycle inhibitor P21, as well as downregulation of cyclin D1, proliferating cell nuclear antigen, and matrix metallopeptidase 9, in parallel with suppression of the Akt/NF-κB pathway. Furthermore, overexpression of RARγ contributed to the multidrug chemoresistance of CCA cells, at least in part due to upregulation of P glycoprotein via activation of the Wnt/β-catenin pathway. Molecular mechanism studies revealed that RARγ interacted with β-catenin and led to β-catenin nuclear translocation. Taken together, our results suggested that RARγ plays an important role in the proliferation, metastasis, and chemoresistance of CCA through simultaneous activation of the Akt/NF-κB and Wnt/β-catenin pathways, serving as a potential molecular target for CCA treatment.

Expression of HBx protein in hepatitis B virus-infected intrahepatic cholangiocarcinoma

BACKGROUND

Hepatitis B virus (HBV) is an etiological factor of intrahepatic cholangiocarcinoma (ICC), but the pathogenic mechanisms remain unclear. This study aimed to investigate the expression and possible role of HBx, an HBV-encoded potentially oncogenic protein, in HBV-infected ICC.

METHODS

Tissue samples were obtained from 54 specimens of HBV-infected ICC. Forty-four specimens were of peripheral type and 10 hilar type. Formalin-fixed, paraffin-embedded sections of the specimens were immunohistochemically stained for HBx and p53.

RESULTS

HBx expression was found in 70.4% (38/54) of the specimens, and it was more frequently seen in the peripheral type than in the hilar type (79.5% vs 30.0%, P=0.002). All three well-differentiated ICCs expressed HBx, whereas 76.9% (30/39) moderately-differentiated and 41.7% (5/12) poorly-differentiated ICCs had HBx expression (P=0.033). Patients with HBx expression had a significantly higher prevalence of elevated serum alpha-fetoprotein (P=0.033). p53 protein expression was found in 18 of 54 cases (33.3%), and was not correlated with that of HBx.

CONCLUSIONS

HBx may contribute to the pathogenesis of ICC, particularly the peripheral type. p53 abnormality may not play a significant role in HBx-mediated oncogenicity during ICC carcinogenesis.

PRKAR1A overexpression is associated with increased ECPKA autoantibody in liver fluke-associated cholangiocarcinoma: application for assessment of the risk group

Cholangiocarcinoma (CCA) associated with Opisthorchis viverrini (Ov) chronic infection is the most frequent primary liver cancer in Thailand, and current approaches to early diagnosis and curative treatments are largely disappointing. We hypothesize a role for protein kinase A (PKA) in Ov-induced CCA. First, we studied the PKA isozyme switching in the liver from the hamster CCA model using quantitative (q) PCR, in situ hybridization, and immunohistochemical and western blot analysis. Second, the presence of extracellular PKA (ECPKA) in CCA cell lines and their conditioned media was demonstrated by western blot and PKA activity assay. Third, we determined the association between PRKAR1A expression and serum ECPKA autoantibody in patients with CCA by ELISA. We demonstrated that an increased PRKAR1A expression is restricted to the biliary cells starting from week 1, with remarkable up-regulation when CCA has completely developed by week 24. The switching of the PKA regulatory subunit isoforms from PRKAR2B/PKAII to PRKAR1A/PKAI is significantly associated with cholangiocyte proliferation. Further, we observed that human CCA cell lines express PRKAR1A but not PRKAR2B and excrete ECPKA. Finally, ECPKA autoantibodies are detected in serum of patients with CCA, adenocarcinoma, and Ov infection with periductal fibrosis, but not from Ov-infected subjects without periductal fibrosis lesion and healthy controls. We conclude that PKA isozyme switching and the PRKAR1A/PKAI pathway might contribute to the induction of cholangiocyte transformation and proliferation in Ov-induced CCA. Overexpression of PRKAR1A leads to secretion of ECPKA which is associated with serum autoantibody that may constitute a biomarker for human CCA genesis.

Adenocarcinoma with pyloric gland phenotype of the extrahepatic bile ducts: a previously unrecognized and distinctive morphologic variant of extrahepatic bile duct carcinoma

Carcinomas of the extrahepatic bile ducts are uncommon and morphologically heterogeneous. We report 3 unique examples of adenocarcinomas that show predominantly pyloric gland differentiation (80%-100%) and compare their immunohistochemical profile with that of pyloric gland adenomas of the gallbladder, foveolar, and intestinal-type adenocarcinomas of the extrahepatic bile duct. The 3 patients with pyloric gland adenocarcinomas were younger than those with conventional adenocarcinomas. The 3 tumors were very well differentiated but showed extensive perineural invasion. They consisted of a variable proportion of small, medium-sized, and cystically dilated glands separated by abundant desmoplastic stroma. The glands were lined by columnar cells with abundant mucin-containing cytoplasm and small hyperchromatic basally placed nuclei with inconspicuous nucleoli. A characteristic feature of these pyloric gland adenocarcinomas was that the glands had a stellar pattern that was not seen in foveolar-, intestinal-, or biliary-type adenocarcinomas. Two pyloric gland adenocarcinomas coexpressed MUC6 and MUC5AC. The diffuse pattern of reactivity of MUC5AC and MUC6 was similar to that of 10 pyloric gland adenomas of the gallbladder and 2 foveolar adenocarcinomas of the extrahepatic bile duct. In contrast, 5 intestinal adenocarcinomas of the extrahepatic bile duct labeled with the intestinal marker CDX2 and 3 with the colonic MUC2 but were negative for MUC6 and MUC5AC. We believe that these pyloric gland adenocarcinomas represent a previously unrecognized distinct clinicopathologic entity. Despite their deceptively benign microscopic appearance, 1 patient died with local recurrence and liver metastasis, another patient is living with tumor, and the third patient is asymptomatic but only 5 months after surgery.

The value of thioredoxin family proteins and proliferation markers in dysplastic and malignant gallbladders in patients with primary sclerosing cholangitis

BACKGROUND AND AIMS

Patients with primary sclerosing cholangitis (PSC) have an increased risk for biliary and gallbladder malignancy and markers of early malignancy in PSC are lacking. The aims were to evaluate biomarkers to look for premalignancy/malignancy.

METHODS

All available gallbladder specimens (n = 53) in patients with PSC at Karolinska University Hospital between 1985 and 2006 were reviewed. Immunohistochemical staining for p53, Ki-67, Cyclin D1 and the thioredoxin family redox proteins; Thioredoxin reductase 1 (TrxR1), isoform-TrxR1-v.2.3.5, Thioredoxin (Trx1) and Glutaredoxin1 (Grx1) was performed on tissues from patients with carcinoma (n = 6), dysplasia (n = 7) and non-cancerous gallbladder epithelium (n = 6).

RESULTS

Dysplasia and carcinoma were found in 16/53 (30%) cases. Inflammation and fibrosis of the gallbladder wall were more common in tissue with gallbladder dysplasia/carcinoma than in benign tissue 12/25 (48%) versus 4/28 (12%) (p < 0.01) and in 13/21 (62%) versus 3/32 (9%) (p < 0.0001), respectively. Immunoreactivity for p53, Ki67, Cyclin D1 was detected in significantly more cases of dysplasia/carcinoma of the gallbladder than in non-cancerous epithelium. 2/19 (11%) of the samples were positive in non-cancerous epithelium versus 7/17 (41%) in dysplasia/carcinoma (p < 0.05) for TrxR1-v.2.3.5. Grx1 was down regulated; more specifically 15/19 (79%) positive cases in non-cancerous epithelium versus 7/17 (41%) in dysplasia/carcinoma.

CONCLUSION

PSC patients have a frequency of gallbladder dysplasia/carcinoma of 30% in operative specimens. The overexpression of TrxR1-v2,3,5 and down regulation of Grx1 in dysplastic gallbladder epithelium suggest that these proteins should be further evaluated as possible future immunohistochemical markers in the early diagnosis of biliary malignancy in PSC.

Precancerous bile duct pathology in end-stage primary sclerosing cholangitis, with and without cholangiocarcinoma

Patients with primary sclerosing cholangitis (PSC) are at increased risk for developing cholangiocarcinoma (CCA). However, the morphology of precursor lesions and the prevalence of biliary dysplasia among patients undergoing liver transplantation for PSC are incompletely defined, and the earlier studies using relatively small number of cases have yielded conflicting results. We retrospectively evaluated 100 consecutive formalin-fixed PSC liver explants (including 30 with CCA) by randomly sampling the hilar and large intrahepatic bile ducts (10 additional tissue cassettes submitted per case). The following histologic features were evaluated and quantitated according to the number of ducts involved: mucinous metaplasia, pyloric metaplasia, intestinal metaplasia, pancreatic acinar metaplasia, and biliary dysplasia [low-grade vs. high-grade (biliary intraepithelial neoplasia-2 or neoplasia-3), papillary vs. flat]. Using Fisher exact test and t test, these features were correlated with the presence or absence of CCA and with the following clinical parameters: sex, age, PSC duration, cirrhotic-stage liver disease, and inflammatory bowel disease at the time of transplant. We found high frequencies of mucinous metaplasia (77%), pyloric metaplasia (73%), and pancreatic acinar metaplasia (10%), which did not differ between CCA and non-CCA livers. However, livers with CCA were more likely to harbor intestinal metaplasia (43% vs. 19%, P=0.013), dysplasia (of any grade) (83% vs. 36%, P<0.0001), and high-grade dysplasia (60% vs. 11%, P<0.0001), and also contained greater numbers of dysplastic ducts than non-CCA cases (P<0.0001). The relative frequency of papillary (44%) versus flat (56%) dysplasia did not differ between CCA and non-CCA cases. Overall, intestinal metaplasia was a significant predictor of bile duct dysplasia (P=0.0005) and CCA (P=0.013), low-grade dysplasia predicted high-grade dysplasia (P<0.0001) and CCA (P=0.0004), and high-grade dysplasia predicted CCA (P<0.0001). Among the clinical parameters, there were no significant differences in age, sex, history of inflammatory bowel disease, or PSC duration, but patients transplanted for CCA were less likely to have cirrhosis (60% vs. 86%, P=0.008). These data strongly support a metaplasia-low-grade dysplasia-high-grade dysplasia-carcinoma sequence in PSC-associated CCA, and underscore the known lack of relationship between patient age and PSC duration in the development of CCA. Even in the absence of CCA, bile duct dysplasia is still a relatively frequent finding, seen at least focally in 36% of benign end-stage PSC explants. Dysplasia, however, is generally confined to large and septal-size bile ducts and its presence may not be recognized unless multiple sections specifically targeted to the biliary tree are examined.

Proximal biliary malignancy

Hilar cholangiocarcinoma is a rare malignancy that occurs at the bifurcation of the bile ducts. Complete surgical excision with negative histologic margins remains the only hope for cure or long-term survival. Because of its location and proximity to the vascular inflow of the liver, surgical resection is technically difficult and may require advanced vascular reconstructions to achieve complete excision. Patients who are not candidates for resection should undergo palliative biliary drainage. The role of neoadjuvant therapy and liver transplantation in the management of hilar cholangiocarcinoma remains to be defined in light of the recent promising results.

Chronic bile duct injury associated with fibrotic matrix microenvironment provokes cholangiocarcinoma in p53-deficient mice

Intrahepatic cholangiocarcinoma (CCA) is a lethal malignancy of the biliary epithelium associated with p53 mutations, bile duct injury, inflammation, and fibrosis. Here, to validate these processes in CCA, we developed a liver cirrhosis model driven by chronic intermittent toxin exposure, which provokes bile duct injury/necrosis and proliferation, fibroblast recruitment, and progressive extracellular matrix (ECM) changes. Fibrotic changes in the matrix microenvironment, typified by increased type I and III collagens and fibroblast recruitment, were shown to stimulate biliary epithelium hyperplasia with subsequent progression to malignant intrahepatic CCA only in mice harboring a p53 mutant allele. These murine CCAs bear histologic and genetic features of human intrahepatic CCA, including dense peritumoral fibrosis, increased inducible nitric oxide synthase, nitrotyrosine, and cyclooxygenase-2 expression, c-Met activation, cErbB2 overexpression, down-regulation of membrane-associated E-cadherin, and p53 codon 248 mutation. Thus, p53 deficiency, chronic bile duct injury/proliferation, and the fibrotic matrix microenvironment cooperate to induce intrahepatic CCA, highlighting the key role of the ECM microenvironment in this common liver cancer.

Biliary tract cancers: molecular profiling as a tool for treatment decisions. A literature review

Biliary tract cancer is a quite rare disease; despite recent significant advances in imaging modalities, most of the patients have advanced disease at presentation thus making radical surgery not feasible. Many different chemotherapeutic regimens have been investigated in small uncontrolled studies, with generally disappointing results. We extensively reviewed the literature on this topic trying to give an explanation to chemoresistance in this setting of patients and considering the molecular profiling as a tool for treatment decision. This review is divided in two parts, in the first one we illustrated chemotherapy results and possible mechanisms of resistance. In the second part we analysed the new molecular targets developing an hypothesis about the future therapeutics perspectives.

Adenovirus-mediated p53 gene transfer to the bile duct by direct administration into the bile in a rat cholangitis model

BACKGROUND

Hepatolithiasis is a common disease in East Asia and its aggravating factor is bile duct stenosis because of refractory cholangitis. This study investigated the feasibility of gene therapy for bile duct stenosis by administration of p53 adenoviral vectors into the bile.

MATERIALS AND METHODS

Adenoviral vectors (AxCALacZ or AxCAhp53) were injected transpapillarily into the bile in the bile duct in a rat model of cholangitis. The extent and duration of the gene expression was evaluated with X-gal staining and p53 immunostaining. The bile duct tissue was examined to evaluate the inhibitory effect on the proliferative changes at 3 and 7 days after administration, and Ki-67 labeling index was determined.

RESULTS

beta-galactosidase was expressed in the bile duct epithelia, the bile duct wall and the surrounding connective tissue. The expression of beta-galactosidase was detected at 4 weeks after the administration. Mean thickness of the bile duct wall at 7 days was 343.2 +/- 14.0 microm for the AxCAhp53 group, 446.5 +/- 25.3 microm for the AxCALacZ group and 447.1 +/- 53.4 microm for the control group. The proliferation of the bile duct wall was significantly suppressed in the AxCAhp53 group (P < 0.05). Maximum thickness was 408.0 +/- 23.9 microm for the AxCAhp53 group (P < 0.05), 650.0 +/- 49.3 microm for the AxCALacZ group, and 590.0 +/- 64.3 microm for the control group. Mean Ki-67 labeling index for the three groups was 20.7% (P < 0.05), 34.4% and 37.4%, respectively.

CONCLUSIONS

P53 gene transfer by administration of the adenoviral vector into the bile suppressed the proliferative changes in the bile duct in a rat cholangitis model.

Regulators of Apoptosis in Cholangiocarcinoma

Context.—Dysregulation of mediators of apoptosis is associated with carcinogenesis. For biliary duct cancers, p53 gene mutation is an important contributor to carcinogenesis. Mutations in the p53 gene affect transcription of the Fas gene, resulting in lack of Fas expression on cell membrane. It has been previously shown that cloned Fas-negative but not Fas-positive human cholangiocarcinoma cells are resistant to anti–Fas-mediated apoptosis and develop tumors in nude mice. In addition, interferon gamma induces Fas expression in Fas-negative cholangiocarcinoma cells and makes them susceptible to apoptosis. Therefore, it becomes important to characterize immunophenotypic expression of p53 and Fas in normal and neoplastic human tissues of the biliary tract to further understand the pathogenesis of the disease. To date, human studies to characterize differences in immunophenotypic expression of the Fas protein between intrahepatic and extrahepatic biliary duct cancers and in their precursor lesions have not been performed.

Objective.—To report the immunophenotypic expression of p53 and Fas expression in various stages in the development of bile duct cancers (intrahepatic and extrahepatic tumor location) and their association with tumor differentiation.

Design.—Thirty bile duct cancer samples (13 intrahepatic and 17 extrahepatic) from 18 men and 12 women who ranged in age from 44 to 77 years (mean age, 65.6 years) were retrieved from the surgical pathology files. Hematoxylin-eosin–stained slides were evaluated for the type and grade of tumor and dysplastic changes in the biliary tract epithelium. Additional slides were immunohistochemically stained with p53 and anti–Fas mouse monoclonal antibody. The pattern of Fas distribution and percentage of cells positive for p53 and Fas expression were determined.

Results.—The percentage of Fas-expressing cells is significantly (P = .01) more frequently noted in extrahepatic tumors compared with intrahepatic tumors. Furthermore, Fas expression decreased from dysplastic epithelium to cholangiocarcinoma (P = .01), and this decreasing trend continued from well to poorly differentiated tumors. Nuclear p53 expression was not identified in normal and dysplastic epithelium but was noted in 30% of carcinomas (P = .02).

Conclusion.—Fas expression is an early event in pathogenesis of bile duct cancers. Immunophenotypic expression of Fas is associated with well to moderately differentiated tumors but not with poor tumor differentiation.

Primary sclerosing cholangitis as a cause of false positive bile duct brushing cytology: Report of two cases

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown etiology characterized by ongoing inflammation, destruction, and fibrosis of intrahepatic and extrahepatic bile ducts. Irregular narrowing and dilation of the biliary duct system produces the characteristic beaded pattern seen on cholangiogram. Malignant degeneration resulting in cholangiocarcinoma is a well-recognized sequela of PSC. Bile duct brushing cytology is the primary screening technique for cholangiocarcinoma. It is associated with a relatively low sensitivity but high specificity. Few false positive bile duct brushings have been reported in the literature, with the majority of these having occurred in a background of PSC. We report two patients with PSC in whom bile duct brush cytologies were falsely positive for carcinoma.

Immunohistochemical analysis of biliary tract lesions

The distinction among inflammatory, benign, and malignant lesions of the biliary tract can at times be difficult. Several methods have been used, including immunohistochemistry (IHC), with variable success. We evaluated a panel of IHC stains to determine their utility in discriminating between bile duct lesions. Formalin-fixed, paraffin-embedded 4-microm sections from 12 inflammatory lesions, 10 bile duct adenomas, and 13 bile duct carcinomas were immunostained using a modified avidin-biotin-complex technique after epitope enhancement using antibodies for p53, Ki-67, and bcl-2. For p53 and bcl-2, greater than 1% of cells staining positive was interpreted as positive. The proliferation index was calculated by determining the number of Ki-67-positive cells in a 1000 cell count. In the inflammatory group, 0 of 12 reacted with anti-p53, 2 of 12 were positive with anti-bcl-2, and the proliferation index with was 22.9% +/- 3.9%. Two of 10 bile duct adenomas showed reactivity with anti-bcl-2, and none were decorated with anti-p53 or Ki-67. In the carcinoma group, 6 of 13 were positive with anti-p53, 9 of 12 were positive with anti-bcl-2, and the proliferation index was 35.3% +/- 5.5%. The proliferation rates differed significantly between groups (P < 0.05). The presence of bcl-2 and p53 immunoreactivity coupled with a high proliferative rate in a biliary tract lesion suggests a malignant process. A panel using these antibodies may be useful in difficult cases.

Identification of novel cellular targets in biliary tract cancers using global gene expression technology

Biliary tract carcinoma carries a poor prognosis, and difficulties with clinical management in patients with advanced disease are often due to frequent late-stage diagnosis, lack of serum markers, and limited information regarding biliary tumor pathogenesis. RNA-based global analyses of gene expression have led to the identification of a large number of up-regulated genes in several cancer types. We have used the recently developed Affymetrix U133A gene expression microarrays containing nearly 22,000 unique transcripts to obtain global gene expression profiles from normal biliary epithelial scrapings (n = 5), surgically resected biliary carcinomas (n = 11), and biliary cancer cell lines (n = 9). Microarray hybridization data were normalized using dCHIP (http://www.dCHIP.org) to identify differentially up-regulated genes in primary biliary cancers and biliary cancer cell lines and their expression profiles was compared to that of normal epithelial scrapings using the dCHIP software as well as Significance Analysis of Microarrays or SAM (http://www-stat.stanford.edu/ approximately tibs/SAM/). Comparison of the dCHIP and SAM datasets revealed an overlapping list of 282 genes expressed at greater than threefold levels in the cancers compared to normal epithelium (t-test P <0.1 in dCHIP, and median false discovery rate <10 in SAM). Several pathways integral to tumorigenesis were up-regulated in the biliary cancers, including proliferation and cell cycle antigens (eg, cyclins D2 and E2, cdc2/p34, and geminin), transcription factors (eg, homeobox B7 and islet-1), growth factors and growth factor receptors (eg, hepatocyte growth factor, amphiregulin, and insulin-like growth factor 1 receptor), and enzymes modulating sensitivity to chemotherapeutic agents (eg, cystathionine beta synthase, dCMP deaminase, and CTP synthase). In addition, we identified several "pathway" genes that are rapidly emerging as novel therapeutic targets in cancer (eg, cytosolic phospholipase A2, an upstream target of the cyclooxygenase pathway, and ribosomal protein S6 kinase and eukaryotic translation initiation factor 4E, two important downstream mediators of the mitogenic Akt/mTOR signaling pathway). Overexpression of selected up-regulated genes was confirmed in tissue microarrays of biliary cancers by immunohistochemical analysis (n = 4) or in situ hybridization (n = 1), and in biliary cancer cell lines by reverse transcriptase PCR (n = 2). The majority of genes identified in the present study has not been previously reported in biliary cancers, and represent novel potential screening and therapeutic targets of this cancer type.

The extrahepatic bile duct lesions in end-stage primary sclerosing cholangitis

We examined histologically the bile duct lesions from 53 patients with end-stage primary sclerosing cholangitis (PSC) and compared them with similar lesions found in 25 surgically excised carcinomas of the extrahepatic bile ducts not associated with PSC. Of the 53 cases of PSC, 50 bile ducts were obtained at liver transplantation, two common bile ducts were segmentally resected for almost complete obstruction, and the entire extrahepatic biliary tract of another case was obtained at autopsy. Twenty bile ducts from patients who died without evidence of biliary tract disease served as controls. A modest increase in the number of intramural glands (mild hyperplasia) was noted in 13 cases (24.5%) of PSC. A marked increase in the number of intramural glands (florid hyperplasia) was found in 14 cases (26.4%) of PSC. In one case of florid hyperplasia, there was perineural and intraneural invasion of benign hyperplastic glands, which still maintained their lobular pattern. All cases of florid hyperplasia of intramural glands were accompanied by extensive fibrosis and marked nerve proliferation. Three of 24 (12.5%) invasive adenocarcinomas of the extrahepatic bile ducts showed mild hyperplasia of intramural glands without excessive nerve proliferation. Four invasive adenocarcinomas and one in situ carcinoma of the extrahepatic bile ducts showed florid hyperplasia of intramural glands (16%). The hyperplastic intramural glands were p53 negative and had low proliferative activity as measured by the low MIB-1 labeling index. In contrast, both in situ and invasive carcinoma expressed p53 protein and had a high MIB-1 labeling index. Focal high-grade dysplasia was found in one case of PSC (1.8%) and a small invasive adenocarcinoma in another (1.8%). Hyperplasia of intramural glands of the extrahepatic bile ducts is a reactive process that lacks specificity and is part of the morphologic spectrum of end-stage PSC. The incidence of dysplasia in PSC is low. Small invasive adenocarcinomas may be incidentally found in end-stage PSC, and detecting their presence before liver transplantation may be impossible.

Malignant liver tumors

Primary malignant liver tumors can arise from different components of the liver, such as hepatocytes, bile duct epithelium, neuroendocrine cells, and mesenchymal cells. A specific diagnosis frequently can be suggested from imaging studies, but biopsy remains the gold standard for definitive diagnosis of liver tumors. Clinical history of chronic liver disease, known risk factors, or other diseases are of great importance. Patient's age is also an important discriminating feature because several tumors such as hepatoblastoma, mesenchymal hamartoma, and infantile hemangioendothelioma, are found predominantly in pediatric populations, whereas cholangiocarcinoma and hepatocellular carcinoma are rare in pediatric populations.

Sclerosing cholangitis

Primary sclerosing cholangitis in children can mimic autoimmune hepatitis in the absence of inflammatory bowel disease. Most adult patients have been identified with human leukocyte antigens that either predispose or protect against disease. Novel class I alleles and cytokine polymorphisms may also contribute to disease susceptibility. Primary alpha-hemolytic streptococci infection does not appear to directly cause primary sclerosing cholangitis. Promising diagnostic modalities such as single photon emission tomography require further study in comparison with cholangiographic techniques. Positron-emission tomography and DNA cytometry appear promising for confirming occult cholangiocarcinoma when present. The chemoprevention effects of ursodeoxycholic acid on colorectal dysplasia await further investigation. Initial results from high-dose ursodeoxycholic acid in halting disease progression, however, suggest a beneficial effect. In contrast, the impact of endoscopic therapy on natural history remains unresolved. Although liver transplantation continues to be effective for end-stage liver disease, disease recurrence in the allograft is a controversial topic.

Atypical bile duct adenoma, clear cell type: a previously undescribed tumor of the liver

A variable proportion of bile duct adenomas of the liver are still confused with metastatic well-differentiated adenocarcinoma by surgeons and pathologists. We present here three examples of previously undescribed primary hepatic bile duct tumors that were composed almost entirely of clear cells that closely mimicked metastatic renal cell carcinoma. They were interpreted as atypical bile duct adenomas and occurred in two males and one female whose ages ranged from 25 to 64 years. All three tumors were incidental findings and measured from 0.8 to 1.1 cm. The clear neoplastic cells showed mild nuclear atypia and no mitotic activity. They were arranged in tubules and nests that focally infiltrated the hepatic parenchyma. For comparison, a case of clear cell cholangiocarcinoma and 13 conventional bile duct adenomas were examined. The clear cell cholangiocarcinoma was larger (6.0 cm) and had the tubular pattern of conventional cholangiocarcinoma and an abundant desmoplastic stroma. The clear cells of this tumor exhibited greater nuclear atypia and increased mitotic activity. All three atypical bile duct adenomas expressed cytokeratin (CK) 7, p53 protein, epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA); they were negative for CK20, vimentin, Hep Par 1, chromogranin, and prostatic specific antigen (PSA) and exhibited less than 10% of Ki-67-positive nuclei. One atypical bile duct adenoma displayed luminal immunoreactivity for villin. With the exception of Ki-67 reactivity, the 13 conventional bile duct adenomas and the clear cell cholangiocarcinoma had essentially a similar immunohistochemical profile as that of the atypical clear cell bile duct adenomas. The absence of an extrahepatic primary tumor, the histologic features, the immunohistochemical profile, and the fact that all patients are symptom-free 2 months to 18 years after wedge liver biopsy support the interpretation of atypical clear cell bile duct adenoma. The differential diagnosis with clear cell hepatocellular carcinoma and metastatic clear cell carcinomas is discussed.