Prognostic assessment of three single-nucleotide polymorphisms (GNB3 825C>T, BCL2-938C>A, MCL1-386C>G) in extrahepatic cholangiocarcinoma

The Role of Single-Nucleotide Polymorphisms in Cholangiocarcinoma: A Systematic Review

Single-nucleotide polymorphisms (SNPs) play an essential role in various malignancies, but their role in cholangiocarcinoma (CCA) remains to be elucidated. Therefore, the purpose of this systematic review was to evaluate the association between SNPs and CCA, focusing on tumorigenesis and prognosis. A systematic literature search was carried out using PubMed, Embase, Web of Science and the Cochrane database for the association between SNPs and CCA, including literature published between January 2000 and April 2022. This systematic review compiles 43 SNPs in 32 genes associated with CCA risk, metastatic progression and overall prognosis based on 34 studies. Susceptibility to CCA was associated with SNPs in genes related to inflammation (PTGS2/COX2, IL6, IFNG/IFN-γ, TNF/TNF-α), DNA repair (ERCC1, MTHFR, MUTYH, XRCC1, OGG1), detoxification (NAT1, NAT2 and ABCC2), enzymes (SERPINA1, GSTO1, APOBEC3A, APOBEC3B), RNA (HOTAIR) and membrane-based proteins (EGFR, GAB1, KLRK1/NKG2D). Overall oncological prognosis was also related to SNPs in eight genes (GNB3, NFE2L2/NRF2, GALNT14, EGFR, XRCC1, EZH2, GNAS, CXCR1). Our findings indicate that multiple SNPs play different roles at various stages of CCA and might serve as biomarkers guiding treatment and allowing oncological risk assessment. Considering the differences in SNP detection methods, patient ethnicity and corresponding environmental factors, more large-scale multicentric investigations are needed to fully determine the potential of SNP analysis for CCA susceptibility prediction and prognostication.

A Novel Machine Learning 13-Gene Signature: Improving Risk Analysis and Survival Prediction for Clear Cell Renal Cell Carcinoma Patients

Simple Summary

Clear cell renal cell carcinoma is a type of kidney cancer which comprises the majority of all renal cell carcinomas. Many efforts have been made to identify biomarkers which could help healthcare professionals better treat this kind of cancer. With extensive public data available, we conducted a machine learning study to determine a gene signature that could indicate patient survival with high accuracy. Through the min-Redundancy and Max-Relevance algorithm we generated a signature of 13 genes highly correlated with patient outcomes. These findings reveal potential strategies for personalized medicine in the clinical practice.

Abstract

Patients with clear cell renal cell carcinoma (ccRCC) have poor survival outcomes, especially if it has metastasized. It is of paramount importance to identify biomarkers in genomic data that could help predict the aggressiveness of ccRCC and its resistance to drugs. Thus, we conducted a study with the aims of evaluating gene signatures and proposing a novel one with higher predictive power and generalization in comparison to the former signatures. Using ccRCC cohorts of the Cancer Genome Atlas (TCGA-KIRC) and International Cancer Genome Consortium (ICGC-RECA), we evaluated linear survival models of Cox regression with 14 signatures and six methods of feature selection, and performed functional analysis and differential gene expression approaches. In this study, we established a 13-gene signature (AR, AL353637.1, DPP6, FOXJ1, GNB3, HHLA2, IL4, LIMCH1, LINC01732, OTX1, SAA1, SEMA3G, ZIC2) whose expression levels are able to predict distinct outcomes of patients with ccRCC. Moreover, we performed a comparison between our signature and others from the literature. The best-performing gene signature was achieved using the ensemble method Min-Redundancy and Max-Relevance (mRMR). This signature comprises unique features in comparison to the others, such as generalization through different cohorts and being functionally enriched in significant pathways: Urothelial Carcinoma, Chronic Kidney disease, and Transitional cell carcinoma, Nephrolithiasis. From the 13 genes in our signature, eight are known to be correlated with ccRCC patient survival and four are immune-related. Our model showed a performance of 0.82 using the Receiver Operator Characteristic (ROC) Area Under Curve (AUC) metric and it generalized well between the cohorts. Our findings revealed two clusters of genes with high expression (SAA1, OTX1, ZIC2, LINC01732, GNB3 and IL4) and low expression (AL353637.1, AR, HHLA2, LIMCH1, SEMA3G, DPP6, and FOXJ1) which are both correlated with poor prognosis. This signature can potentially be used in clinical practice to support patient treatment care and follow-up.

Prognostic and Predictive Molecular Markers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary liver cancer and subsumes a heterogeneous group of malignant tumors arising from the intra- or extrahepatic biliary tract epithelium. A rising mortality from CCA has been reported worldwide during the last decade, despite significant improvement of surgical and palliative treatment. Over 50% of CCAs originate from proximal extrahepatic bile ducts and constitute the most common CCA entity in the Western world. Clinicopathological characteristics such as lymph node status and poor differentiation remain the best-studied, but imperfect prognostic factors. The identification of prognostic molecular markers as an adjunct to traditional staging systems may not only facilitate the selection of patients who would benefit the most from surgical, adjuvant or palliative treatment strategies, but may also be helpful in defining the aggressiveness of the disease and identifying patients at high-risk for tumor recurrence. The purpose of this review is to provide an overview of currently known molecular prognostic and predictive markers and their role in CCA.

Cholangiocarcinoma and liver transplantation: What we know so far?

Cholangiocarcinoma (CCA) is a type of cancer with increasing prevalence around the world that originates from cholangiocytes, the epithelial cells of the bile duct. The tumor begins insidiously and is distinguished by high grade neoplasm, poor outcome, and high risk for recurrence. Liver transplantation has become broadly accepted as a treatment option for CCA. Liver transplantation is expected to play a crucial role as palliative and curative therapy for unresectable hilar CCA and intrahepatic CCA. The purpose of this study was to determine which cases with CCA should be subjected to liver transplantation instead of resection, although reported post-transplant recurrence rate averages approximately 20%. This review also aims to highlight the molecular current frontiers of CCA and directions of liver transplantation for CCA.

Correlation Between BCL2 and Mcl1 Single Nucleotide Polymorphisms and Chemotherapy Response in Jordanian Patients with Colorectal Cancer

BACKGROUND

Colorectal cancer is one of the most common types of cancer worldwide and a leading cause of death in Jordan. BCL-2 and MCL-1 are anti-apoptotic proteins that inhibit programmed cell death and their over-expression has been shown to be associated with reduced sensitivity to chemotherapy and poor survival in cancer patients.

OBJECTIVES

In the present study, three SNPs in the promoter region of antiapoptotic genes were investigated in an effort to inspect the occurrences of SNPs (rs2279115, rs4987852) in the promoter region of BCL2 and SNP (rs9803935) in the promoter region of MCL1 in Jordanian patients with CRC, and investigate correlations between BCL2 and MCL1 SNPs and clinical outcomes.

METHODS

PCR-restriction fragment length polymorphism (RFLP)-based analysis was used for samples genotyping.

RESULTS

The BCL2 rs2279115 and MCL1 rs9803935 SNPs showed significant distribution where mutant and hetero genotypes are more prominent in CRC patients. Additionally, the rs2279115 genotypes and alleles were associated with stages of disease, its recurrence and metastasis. The MCL1 rs9803935 genotypes were associated disease metastasis. However, for BCL2 rs4987852 SNP, there was no association of genotypes or alleles with any of the disease variables.

CONCLUSION

The BCL2 SNPs (rs2279115) and MCL1 SNP (rs9803935) present as important determinants of the progress of CRC in Jordanian patients.

BAX -248 G>A and BCL2 -938 C>A Variant Lowers the Survival in Patients with Nasopharyngeal Carcinoma and Could be Associated with Tissue-Specific Malignancies: A Multi-Method Approach

BACKGROUND

The association of BAX -248 G>A and BCL2 -938 C>A with different cancers created conflicts.  We studied the correlation and the effect of these polymorphisms in patients with Nasopharyngeal Carcinoma (NPC).  Methods: PCR-RFLP and Sanger sequencing were used to detect polymorphisms. Statistical analysis including forest plot and Kaplan-Meier Log-rank test was conducted to investigate the association and effect of these SNPs on the NPC patients' survival. The computational study was performed to investigate the possible regulatory role between these polymorphisms and the poor survival of NPC patients. Meta-analysis was executed to check the tissue-specific association of these polymorphisms in the context of global cancer prognosis.

RESULTS

We observed an increased and significant association of BAX -248 G>A [GA:OR=5.29, 95%CI=1.67,16.67, P=0.004; GA+AA:OR=5.71, 95%CI=1.82,17.90, P =0.002; A:OR=5.33, 95%CI=1.76,16.13, P=0.003], and BCL2 -938 C>A [CA:OR=2.26, 95%CI=1.03,4.96, P=0.04; AA:OR=3.56, 95%CI=0.97,13.05, P=0.05; CA+AA:OR=3.10, 95%CI=1.51,6.35, P=0.002; A:OR=2.90, 95% CI=1.59,5.29, P=0.0005] with the risk of NPC. Also, these SNPs were strongly correlated with poor survival in NPC patients (lower estimated survival mean, lower estimated proportion surviving at 5 years with p <0.05). The computational study showed that these SNPs altered the binding affinity of transcription factors HIF1, SP1, PAX3, PAX9 and CREB towards promoter (Lower p indicates strong affinity). The meta-analysis revealed the tissue-specific association of these polymorphisms. BAX -248 G>A showed a significant correlation with carcinomas [A vs G:OR=1.60, 95%CI=1.09,2.34, P=0.01; AA vs GG:OR=2.61, 95%CI=1.68,4.06, p <0.001; AA+GA vs GG:OR=1.53,95%CI=1.04,2.25, P=0.02); AA vs GG+GA:OR=2.53, 95%CI=1.65,3.87, p <0.001], and BCL2 -938 C>A with other malignancies [A vs C:OR=1.45, 95%CI=1.26,1.66, p <0.001; AA vs CC:OR=2.07, 95%CI: 1.15,3.72, P=0.01; AA+CA vs CC:OR=1.42, 95%CI=1.18,1.72, p <0.001; AA vs CC+CA:OR=1.89, 95%CI=1.02,3.50, P=0.04].

CONCLUSIONS

BAX -248 G>A and BCL2 -938 C>A was associated with poor survival in NPC patients. It may increase cancer susceptibility through transcriptional regulation. Moreover, these SNPs' effects could be tissue-specific.
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Biliary Tract Cancers: Molecular Heterogeneity and New Treatment Options

Most patients with biliary tract cancer (BTC) are diagnosed with advanced disease, relapse rates are high in those undergoing surgery and prognosis remains poor, while the incidence is increasing. Treatment options are limited, and chemotherapy is still the standard of care in both adjuvant and advanced disease setting. In recent years, different subtypes of BTC have been defined depending on the anatomical location and genetic and/or epigenetic aberrations. Especially for intrahepatic cholangiocarcinoma (iCCA) novel therapeutic targets have been identified, including fibroblast growth factor receptor 2 gene fusions and isocitrate dehydrogenase 1 and 2 mutations, with molecularly targeted agents having shown evidence of activity in this subgroup of patients. Additionally, other pathways are being evaluated in both iCCA and other subtypes of BTC, alongside targeting of the immune microenvironment. The growing knowledge of BTC biology and molecular heterogeneity has paved the way for the development of new therapeutic approaches that will completely change the treatment paradigm for this disease in the near future. This review provides an overview of the molecular heterogeneity of BTC and summarizes new targets and emerging therapies in development. We also discuss resistance mechanisms, open issues, and future perspectives in the management of BTC.

Molecular Features and Targeted Therapies in Extrahepatic Cholangiocarcinoma: Promises and Failures

Biliary tract cancers (BTCs) include a heterogenous group of aggressive malignancies with limited therapeutic options. According to their anatomical location, these hepatobiliary tumors are usually classified into intrahepatic cholangiocarcinoma (iCCA), extrahepatic cholangiocarcinoma (eCCA), and gallbladder cancer (GBC). Unfortunately, BTCs are often diagnosed when already metastatic, and although the advent of genomic sequencing has led to a deeper understanding of iCCA pathogenesis, very little data are currently available about the molecular landscape of eCCA. Moreover, despite novel systemic treatments emerging in BTC, the grim prognosis of eCCA patients has not changed in the past decade, and no targeted therapies have been approved so far. The aim of the current review is to provide an overview regarding molecular features and potential targeted therapies in eCCA, together with novel therapeutic approaches and future directions of translational and clinical research on this highly aggressive disease that poses many unanswered questions.

Molecular and Immunological Characterization of Biliary Tract Cancers: A Paradigm Shift Towards a Personalized Medicine

Biliary tract cancers (BTCs) are a group of rare cancers that account for up to 3-5% of cancer patients worldwide. BTCs include cholangiocarcinoma (CCA), gallbladder cancer (GBC), and ampulla of Vater cancer (AVC). They are frequently diagnosed at an advanced stage when the disease is often found disseminated. A late diagnosis highly compromises surgery, the only potentially curative option. Current treatment regimens include a combination of chemotherapeutic drugs gemcitabine with cisplatin that have a limited efficiency since more than 50% of patients relapse in the first year. More recently, an inhibitor of fibroblast growth factor receptor 2 (FGFR2) was approved as a second-line treatment, based on the promising results from the NCT02924376 clinical trial. However, novel secondary treatment options are urgently needed. Recent molecular characterization of CCA and GBC highlighted the molecular heterogeneity, etiology, and epidemiology in BTC development and lead to the classification of the extrahepatic CCA into four types: metabolic, proliferating, mesenchymal, and immune type. Differences in the immune infiltration and tumor microenvironment (TME) have been described as well, showing that only a small subset of BTCs could be classified as an immune "hot" and targeted with the immunotherapeutic drugs. This recent evidence has opened a way to new clinical trials for BTCs, and new drug approvals are highly expected by the medical community.

Long-term Survival after resection for perihilar cholangiocarcinoma: Impact of UICC staging and surgical procedure

BACKGROUND/AIMS

Perihilar cholangiocarcinoma is a rare disease with unfavorable prognosis resulting in low survival rates. This study aims to retrospectively assess the beneficial histopathological features and surgical procedures in long-term survivors (i.e., patients surviving perihilar cholangiocarcinoma for at least 2 y).

MATERIAL AND METHODS

In total, 322 patients with perihilar cholangiocarcinoma underwent surgery at our center. The follow-up ended in 2017; 76 patients survived for >2 y. The type of resection, UICC stage, and histopathological features were compared between three survival groups (>2-3, >3-5, and >5 y).

RESULTS

The >5-year-survival rate in our selected study cohort was 43.4% (>3-5 y,31.6% and >2-3 y, 25.0%), and 14.5% of the patients survived for >10 y after surgery. Patients with non-regional lymph node positive tumors and/or distant metastasis (i.e., UICC stage IVb; p=0.0112), R2 status (p=0.0288), and exploratory laparotomy only (p=0.0157) showed the poorest survival rates. Perineural invasion had no significant impact on the overall survival. However, 29.0% patients surviving for >5 y displayed the lowest perineural infiltration prevalence. Interestingly, Bismuth-Corlette stage IIIa (p=0.0467), especially caudate lobectomy (p=0.0034), was associated with disease-specific overall survival of >5y.

CONCLUSION

Complete/extended tumor resection with additional caudate lobe resection is strongly associated with long-term survival. Perineural infiltration as a negative prognostic marker for prolonged survival needs to be evaluated in larger study cohorts.

Molecular perturbations in cholangiocarcinoma: Is it time for precision medicine?

The complexity of cholangiocarcinoma (CCA) cellularity and the molecular perturbation mechanisms that underlie the diversity of growth patterns of this malignancy remain a clinical concern. Tumours of the biliary system display significant intrinsic chemoresistance, caused by significant stromal involvement and genome-wide tumour heterogeneity, hampering disease remission and palliation as well as promoting the metastatic behaviour. It is crucial to advance our present understanding of the risk and molecular pathogenesis of CCA. This will facilitate the delineation of patient subsets based on molecular perturbations and adjust for precision therapies.

Comparison of the sixth and the seventh editions of the UICC classification for intrahepatic cholangiocarcinoma

Background

The current seventh edition of the TNM classification for intrahepatic cholangiocarcinoma (ICC) includes tumor number, vascular invasion, lymph node involvement but no longer the tumor size as compared to the sixth edition. The impact of the seventh edition on stage-based prognostic prediction for patients with ICC was evaluated.

Methods

Between 03/2001 and 02/2013, 98 patients with the diagnosis of an ICC were surgically treated at our center. Median survival times were calculated for these patients after separate classification by both sixth and seventh editions.

Results

Median overall survival was increased in patients classified to the lower tumor stages I and II using the seventh as compared to the sixth edition: stage I (54.9 vs. 47.3 months), stage II (19.9 vs. 18.9 months), stage III (17.2 vs. 19.9 months), and stage IV (23.2 vs. 15.3 months), respectively. The seventh edition definition of the T category resulted in an increased median survival regarding the T1 (50.4 vs. 47.3 months) as well as the T2 category (19.9 vs. 15.6 months) and revealed a reduced median survival of patients within the T3 (21.6 vs. 24.8 months) as well as the T4 category (19.9 vs. 27.0 months).

Conclusions

The UICC seventh edition TNM classification for ICC improves separation of patients with intermediate stage tumors as compared to the sixth edition. The prognostic value of the UICC staging system has been improved by the seventh edition.

Trial registration The data for this study have been retrospectively registered and the study has been approved by the ethic committee of the medical faculty of the University Hospital of Essen, Germany (license number 15-6353-BO).

Genetic polymorphisms of Bcl-2 promoter in cancer susceptibility and prognosis: a meta-analysis

Bcl-2 is critical for tumorigenesis. However, previous studies on the association of Bcl-2 promoter polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed this meta-analysis regarding the relationship between Bcl-2 promoter single nucleotide polymorphisms (SNPs) and cancer susceptibility and prognosis. Up to August 2016, 32 original publications were identified covering two Bcl-2 promoter SNPs (rs2279115 and rs1801018). Our results showed statistically significant association between rs2279115 and cancer susceptibility and prognosis in all four genetic models but not in rs1801018. Subgroups analysis indicated that rs2279115 was associated with a significantly higher risk of cancer susceptibility in Asia but not in Caucasian. Furthermore, rs2279115 was associated with a significantly higher risk in digestive system cancer and endocrine system cancer but not in breast cancer, respiratory cancer and hematopoietic cancer. Simultaneously, rs2279115 was correlated with a significantly higher risk of cancer prognosis in Asia but not in Caucasian. Considering these promising results, rs2279115 may be a tumor marker for cancertherapy in Asia. Sensitivity analysis show four gene model were stable, and no publication bias was observed in all four gene model. Large sample size, different ethnic population and different cancer type are warranted to validate this association.

Bcl-2 degradation is an additional pro-apoptotic effect of polo-like kinase inhibition in cholangiocarcinoma cells

AIM

To examine the influence on apoptotic mechanisms following inhibition of polo-like kinases as therapeutically approach for cholangiocellular cancer treatment.

METHODS

As most cholangiocarcinomas are chemotherapy-resistant due to mechanisms preventing tumor cell death, we investigated the effect of Cisplatin on cholangiocellular carcinoma (CCA) cell lines KMCH-1 and Mz-Ch-1. Polo-like kinases (PLK) are important regulators of the cell cycle and their inhibition is discussed as a potential therapy while PLK inhibition can regulate apoptotic mediators. Here, cells were treated with PLK inhibitor BI6727 (Volasertib), Cisplatin, and in combination of both compounds. Cell viability was assessed by MTT; apoptosis was measured by DAPI staining and caspase-3/-7 assay. Western blot and qRT-PCR were used to measure expression levels of apoptosis-related molecules Bax and Bcl-2.

RESULTS

The cell viability in the CCA cell lines KMCH-1 and Mz-Ch-1 was reduced in all treatment conditions compared to vehicle-treated cells. Co-treatment with BI6727 and cisplatin could even enhance the cytotoxic effect of cisplatin single treatment. Thus, co-treatment of cisplatin with BI6727 could slightly enhance the cytotoxic effect of the cisplatin in both cell lines whereas there was evidence of increased apoptosis induction solely in Mz-Ch-1 as compared to KMCH-1. Moreover, PLK inhibition decreases protein levels of Bcl-2; an effect that can be reversed by the proteasomal degradation inhibitor MG-132. In contrast, protein levels of Bax were not found to be altered by PLK inhibition. These findings indicate that cytotoxic effects of Cisplatin in Mz-Ch-1 cells can be enhanced by cotreatment with BI6727.

CONCLUSION

In conclusion, BI6727 treatment can sensitize CCA cells to cisplatin-induced apoptosis with proteasomal Bcl-2 degradation as an additional pro-apoptotic effect.

Polo-like kinase 3 is associated with improved overall survival in cholangiocarcinoma

BACKGROUND & AIMS

Cholangiocarcinomas (CCA) paradoxically express the death ligand TRAIL and thus, are dependent on effective survival signals to circumvent apoptosis. Hedgehog signalling exerts major survival signals in CCA by regulating serine/threonine kinase polo-like kinase (PLK)2. We here aimed to examine the role of PLK1/2/3 expression for CCA tumour biology.

METHODS

We employed CCA samples from 73 patients and human HUCCT-1/Mz-CHA1/KMCH-1 CCA cells. Immunohistochemistry for PLK1/2/3 was performed using tissue microarrays from representative tumour areas.

RESULTS

PLK1/2/3-immunoreactive cancer cells were present in most of the CCA samples. However, only PLK1 and especially PLK3 were expressed in higher amounts within CCA cells as compared to normal liver. Given that fibroblast growth factor (FGF) can induce PLK3 expression and also is present in CCA, we examined the effect of FGF on PLK3 in vitro. Indeed, rhFGF rapidly increased PLK3 mRNA expression all three CCA cell lines giving an explanation for the abundant PLK3 presence in the tissue samples. Clinicopathologically, PLK3 expression was associated with decreased tumour cell migration and lymph/blood vessel infiltration whereas higher levels of PLK1 were correlated with larger tumour sizes. Moreover, strong PLK3 expression was associated with prolonged overall survival.

CONCLUSIONS

The results suggest that PLK3 predominantly is expressed in CCA cells and that high PLK3 expression correlates with prolonged overall survival. These observations might have implications for prognosis prediction of human CCA as well as the potential therapeutic use of polo-like kinase inhibitors (i.e., PLK1/2 specifity).

Role of Bcl-2 -938 C>A polymorphism in susceptibility and prognosis of cancer: a meta-analysis

The association between B-cell lymphoma 2 (Bcl-2) polymorphism and cancer is under debate and remains elusive. This meta-analysis was performed to evaluate the relationships of Bcl-2 -938 C>A polymorphism (rs2279115) with susceptibility and prognosis of cancer. Odds ratios (ORs) were used to measure the association between Bcl-2 polymorphisms and cancer risk. Hazard ratios (HRs) were used to measure the association between Bcl-2 polymorphisms and cancer prognosis. On the basis of 26 studies about Bcl-2 -938C>A polymorphism and cancer, we found Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in dominant model (OR = 1.12, 95%CI: 1.00-1.25, P = 0.04), recessive model (OR = 1.38, 95%CI: 1.11-1.71, P = 0.004), allelic model (OR = 1.15, 95%CI: 1.04-1.28, P = 0.007) and homozygote comparison(OR = 1.44, 95%CI: 1.11-1.87, P = 0.006). Furthermore, Bcl-2 -938 C>A polymorphism was significantly associated with increased cancer risk in Asians but not in Caucasians. Moreover, Bcl-2 -938 C>A polymorphism was not significantly associated with the prognosis of cancer (AA vs CA: OR = 0.99, 95%CI: 0.77-1.27, P = 0.93; AA vs CC: OR = 0.92, 95%CI: 0.65-1.30, P = 0.63; AC vs CC: OR = 0.94, 95%CI: 0.80-1.11, P = 0.48; CC vs AA+CA: OR = 1.21, 95%CI: 0.69-2.13, P = 0.50; AA vs CC+CA: OR = 0.99, 95%CI: 0.48-2.04, P = 0.97). Studies with larger samples and gene-environment interactions are needed to validate our findings.

A review of the clinical diagnosis and therapy of cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary hepatic malignancy worldwide. The incidence of intrahepatic CCA is increasing, whereas that of extrahepatic CCA is decreasing. This review looks at the new advances that have been made in the management of CCA, based on a PubMed and Science Citation Index search of results from randomized controlled trials, reviews, and cohort, prospective and retrospective studies. Aggressive interventional approaches and new histopathological techniques have been developed to make a histological diagnosis in patients with high risk factors or suspected CCA. Resectability of the tumour can now be assessed using multiple radiological imaging studies; the main prognostic factor after surgery is a histologically negative resection margin. Biliary drainage and/or portal vein embolization may be performed before extended radical resection, or liver transplantation may be undertaken in combination with neoadjuvant chemotherapy or chemoradiotherapy. Though many advances have been made in the management of CCA, the standard modality of treatment has not yet been established. This review focuses on the clinical options for different stages of CCA.

Polo-like kinase 2 is a mediator of hedgehog survival signaling in cholangiocarcinoma

Cholangiocarcinoma (CCA) cells paradoxically express the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and thus rely on potent survival signals to circumvent cell death by TRAIL. Hedgehog (Hh) signaling is an important survival pathway in CCA. Herein, we further examine the mechanisms whereby Hh signaling mediates apoptosis resistance in CCA, revealing a pivotal role for the cell division regulating serine/threonine kinase polo-like kinase 2 (PLK2). We employed 50 human CCA samples (25 intrahepatic and 25 extrahepatic CCA) as well as human KMCH-1, Mz-CHA-1, and HUCCT-1 CCA cells for these studies. In vivo experiments were conducted using a syngeneic rat orthotopic CCA model. In human samples, polo-like kinase (PLK)1/2/3-immunoreactive cancer cells were present in the preponderance of intra- and extrahepatic CCA specimens. Inhibition of Hh signaling by cyclopamine reduced PLK2, but not PLK1 or PLK3, messenger RNA and protein expression in vehicle-treated and sonic Hh-treated CCA cells, confirming our previous microarray study. PLK2 regulation by Hh signaling appears to be direct, because the Hh transcription factors, glioma-associated oncogene 1 and 2, bind to the PLK2 promotor. Moreover, inhibition of PLK2 by the PLK inhibitor, BI 6727 (volasertib), or PLK2 knockdown was proapoptotic in CCA cells. BI 6727 administration or PLK2 knockdown decreased cellular protein levels of antiapoptotic myeloid cell leukemia 1 (Mcl-1), an effect reversed by the proteasome inhibitor, MG-132. Finally, BI 6727 administration reduced Mcl-1 protein expression in CCA cells, resulting in CCA cell apoptosis and tumor suppression in vivo.

CONCLUSION

PLK2 appears to be an important mediator of Hh survival signaling. These results suggest PLK inhibitors to be of therapeutic value for treatment of human CCA.

Molecular biomarkers in extrahepatic bile duct cancer patients undergoing chemoradiotherapy for gross residual disease after surgery

Purpose

To analyze the outcomes of chemoradiotherapy for extrahepatic bile duct (EHBD) cancer patients who underwent R2 resection or bypass surgery and to identify prognostic factors affecting clinical outcomes, especially in terms of molecular biomarkers.

Materials and Methods

Medical records of 21 patients with EHBD cancer who underwent R2 resection or bypass surgery followed by chemoradiotherapy from May 2001 to June 2010 were retrospectively reviewed. All surgical specimens were re-evaluated by immunohistochemical staining using phosphorylated protein kinase B (pAKT), CD24, matrix metalloproteinase 9 (MMP9), survivin, and β-catenin antibodies. The relationship between clinical outcomes and immunohistochemical results was investigated.

Results

At a median follow-up of 20 months, the actuarial 2-year locoregional progression-free, distant metastasis-free and overall survival were 37%, 56%, and 54%, respectively. On univariate analysis using clinicopathologic factors, there was no significant prognostic factor. In the immunohistochemical staining, cytoplasmic staining, and nuclear staining of pAKT was positive in 10 and 6 patients, respectively. There were positive CD24 in 7 patients, MMP9 in 16 patients, survivin in 8 patients, and β-catenin in 3 patients. On univariate analysis, there was no significant value of immunohistochemical results for clinical outcomes.

Conclusion

There was no significant association between clinical outcomes of patients with EHBD cancer who received chemoradiotherapy after R2 resection or bypass surgery and pAKT, CD24, MMP9, survivin, and β-catenin. Future research is needed on a larger data set or with other molecular biomarkers.

Comparison of the sixth and the seventh editions of the UICC classification for perihilar cholangiocarcinoma

BACKGROUND

The seventh edition of the TNM classification separates extrahepatic bile duct tumors into perihilar and distal tumors and further changes the definition of the TNM classification. The impact of the seventh edition on stage-based prognostic prediction for patients with perihilar cholangiocarcinoma was evaluated.

METHODS

Between January 1998 and March 2010, 223 consecutive patients with perihilar cholangiocarcinoma underwent surgery at the West German Cancer Center. Median survival times were calculated for the 195 evaluable patients (excluding those with in-hospital mortality) after separate classification by both sixth and seventh editions.

RESULTS

Median overall survival was increased in patients classified using the seventh compared with the sixth edition (UICC I: 56.5 vs 23.75 months; II: 45.9 vs 31.6 months; III: 21.3 vs. 8.76 months; IV: 7.03 vs 5.93 months). The T category of the seventh edition did not alter median survival times of T1 (54.07 months) and T4 (7.83 months) cases, but median survival was prolonged for T2 patients (29.4 vs 31.6 months), and shortened for T3 patients (19.43 vs 11.8 months) staged using the seventh edition. According to Cox proportional hazards regression analysis, patient survival was better predicted by the seventh edition UICC stage and pT categories (p=0.0014 and p=0.0396, respectively), than the corresponding sixth edition categories (p=0.4376 and p=0.0926, respectively).

CONCLUSIONS

The UICC seventh edition TNM classification for perihilar cholangiocarcinoma improves separation of patients with intermediate stage tumors compared with the sixth edition. The prognostic value of the UICC staging system has been strengthened by the introduction of the seventh edition.

Role of stress-induced NKG2D ligands in liver diseases

Cell death by apoptosis is a prominent feature in a variety of liver diseases. It is likely that apoptosis is the initial cellular response to hepatocyte and biliary injury, which then leads to the initiation of cellular and cytokine cascades culminating in hepatocyte death with subsequent fibrosis and cirrhosis. This sequence of events is of paramount clinical importance. Recently, soluble forms of the major histocompatibility complex class I-related chains A and closely related B (MIC A and B) were reported to be increased in patients with a variety of liver diseases. MIC A and B are cell surface glycoproteins that function as indicators for cellular stress and thus activate circulating cytotoxic natural killer (NK) cells. The interaction between MIC A and B with their cognate receptor natural killer group 2 member D (NKG2D) culminates in enhanced liver cell death, which is mediated in part by apoptotic mechanisms. The present overview focuses on the role of the stress-induced NKG2D ligands MIC A and B in diverse liver diseases. Critical insights into these complex relations may help to promote rationally based therapies in liver diseases. Importantly, we hope that this overview will help to stimulate further studies into mechanisms by which stress ligands mediate cell death and its sequale.

Targeting PDGFR-β in Cholangiocarcinoma

BACKGROUND

Cholangiocarcinomas (CCAs) are highly desmoplastic neoplasms with a tumour microenvironment plentiful in myofibroblasts (MFBs). MFB-derived PDGF-BB survival signalling is a mediator of CCA cell resistance to apoptotic stimuli. This raises the concept that targeting PDGFR-β, a cognate receptor of PDGF-BB, represents a potential strategy for the treatment of human CCA.

AIMS

Herein, we examine a role for inhibiting PDGFR-β in restoring CCA cell sensitivity to apoptotic stimuli in vitro and in vivo.

METHODS

We employed human CCA samples from 41 patients (19 intrahepatic and 22 extrahepatic CCA samples), the human CCA cell lines KMCH-1 and HUCCT-1 as well as shPDGFR-β-KMCH-1 and human myofibroblastic LX-2 cells for these studies. In vivo-experiments were conducted using a syngeneic rat orthotopic CCA model.

RESULTS

Of several MFB-derived growth factors profiled, PDGF-BB and CTGF were most abundantly expressed; however, only PDGF-BB attenuated tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity. Co-culturing CCA cells with PDGF-BB-secreting MFBs significantly decreased TRAIL-induced CCA cell apoptosis when compared with monoculture conditions; this cytoprotective effect was abrogated in the presence of the tyrosine kinase inhibitors imatinib mesylate or linifanib, which inhibit PDGFR-β. Consistent with these findings, MFB-imparted cytoprotection also was abolished when PDGFR-β was knocked down as demonstrated in shPDGFR-β-KMCH-1 cells. Finally, administration of imatinib mesylate increased CCA cell apoptosis and reduced tumour growth in a rodent in vivo-CCA model that mimics the human disease.

CONCLUSIONS

Targeting PDGFR-β sensitizes CCA cells to apoptotic stimuli and appears to be therapeutic in vivo.

Myofibroblast-derived PDGF-BB promotes Hedgehog survival signaling in cholangiocarcinoma cells

Cholangiocarcinoma (CCA) cells paradoxically express the death ligand, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and, therefore, are dependent upon potent survival signals to circumvent TRAIL cytotoxicity. CCAs are also highly desmoplastic cancers with a tumor microenvironment rich in myofibroblasts (MFBs). Herein, we examine a role for MFB-derived CCA survival signals. We employed human KMCH-1, KMBC, HuCCT-1, TFK-1, and Mz-ChA-1 CCA cells, as well as human primary hepatic stellate and myofibroblastic LX-2 cells, for these studies. In vivo experiments were conducted using a syngeneic rat orthotopic CCA model. Coculturing CCA cells with myofibroblastic human primary hepatic stellate cells or LX-2 cells significantly decreased TRAIL-induced apoptosis in CCA cells, a cytoprotective effect abrogated by neutralizing platelet-derived growth factor (PDGF)-BB antiserum. Cytoprotection by PDGF-BB was dependent upon Hedgehog (Hh) signaling, because it was abolished by the smoothened (SMO; the transducer of Hh signaling) inhibitor, cyclopamine. PDGF-BB induced cyclic adenosine monophosphate-dependent protein kinase-dependent trafficking of SMO to the plasma membrane, resulting in glioma-associated oncogene (GLI)2 nuclear translocation and activation of a consensus GLI reporter gene-based luciferase assay. A genome-wide messenger RNA expression analysis identified 67 target genes to be commonly up- (50 genes) or down-regulated (17 genes) by both Sonic hedgehog and PDGF-BB in a cyclopamine-dependent manner in CCA cells. Finally, in a rodent CCA in vivo model, cyclopamine administration increased apoptosis in CCA cells, resulting in tumor suppression.

CONCLUSIONS

MFB-derived PDGF-BB protects CCA cells from TRAIL cytotoxicity by a Hh-signaling-dependent process. These results have therapeutical implications for the treatment of human CCA.

SNPs in genes encoding G proteins in pharmacogenetics

Heterotrimeric guanine-binding proteins (G proteins) transmit signals from the cell surface to intracellular signal cascades and are involved in various physiological and pathophysiological processes. Polymorphisms in the genes GNB3 (encoding the Gβ3 subunit), GNAS (encoding the Gαs subunit) and GNAQ (encoding the Gαq subunit) have been the primary focus of investigation. Polymorphisms in these genes could be associated with different complex phenotypes underlining that alterations in G-protein signaling can cause multiple disorders. G proteins present a point of convergence or ‘bottleneck’ between various receptors and effectors, thus making them a sensible tool for pharmacogenetic studies. The pharmacogenetic studies performed to date mostly demonstrate an association between G-protein polymorphisms and response to therapy or occurrence of adverse drug effects. Therefore, polymorphisms in genes encoding G-protein subunits may help to individualize drug treatment in various diseases with regard to both efficacy and safety.