A perspective on molecular therapy in cholangiocarcinoma: present status and future directions

Genomic perturbations reveal distinct regulatory networks in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma remains a highly heterogeneous malignancy that has eluded effective patient stratification to date. The extent to which such heterogeneity can be influenced by individual driver mutations remains to be evaluated. Here, we analyzed genomic (whole-exome sequencing, targeted exome sequencing) and epigenomic data from 496 patients and used the three most recurrently mutated genes to stratify patients (IDH, KRAS, TP53, "undetermined"). Using this molecular dissection approach, each subgroup was determined to possess unique mutational signature preferences, comutation profiles, and enriched pathways. High-throughput drug repositioning in seven patient-matched cell lines, chosen to reflect the genetic alterations specific for each patient group, confirmed in silico predictions of subgroup-specific vulnerabilities linked to enriched pathways. Intriguingly, patients lacking all three mutations ("undetermined") harbored the most extensive structural alterations, while isocitrate dehydrogenase mutant tumors displayed the most extensive DNA methylome dysregulation, consistent with previous findings.

CONCLUSION

Stratification of intrahepatic cholangiocarcinoma patients based on occurrence of mutations in three classifier genes (IDH, KRAS, TP53) revealed unique oncogenic programs (mutational, structural, epimutational) that influence pharmacologic response in drug repositioning protocols; this genome dissection approach highlights the potential of individual mutations to induce extensive molecular heterogeneity and could facilitate advancement of therapeutic response in this dismal disease. (Hepatology 2018).

High mobility group A1 enhances tumorigenicity of human cholangiocarcinoma and confers resistance to therapy

High mobility group A1 (HMGA1) protein has been described to play an important role in numerous types of human carcinoma. By the modulation of several target genes HMGA1 promotes proliferation and epithelial-mesenchymal transition of tumor cells. However, its role in cholangiocarcinoma (CCA) has not been addressed yet. Therefore, we determined HMGA1 mRNA expression in CCA samples in a transcriptome array (n = 104) and a smaller cohort (n = 13) by qRT-PCR. Protein expression was evaluated by immunohistochemistry in a tissue microarray (n = 67). In addition, we analyzed changes in cell proliferation, colony formation, response to gemcitabine treatment, and target gene expression after modulation of HMGA1 expression in CCA cell lines. mRNA levels of HMGA1 were found to be upregulated in 15-62% depending on the cohort analyzed. Immunohistochemistry showed HMGA1 overexpression in 51% of CCA specimens. Integration with clinico-pathological data revealed that high HMGA1 expression was associated with reduced time to recurrence and a positive lymph node status in extrahepatic cholangiocellular carcinoma. In vitro experiments showed that overexpression of HMGA1 in CCA cell lines promoted cell proliferation, whereas its suppression reduced growth rate. HMGA1 further promoted colony formation in an anchorage independent growth and conferred resistance to gemcitabine treatment. Finally, HMGA1 modulated the expression of two genes involved in CCA carcinogenesis, iNOS and ERBB2. In conclusion, our findings indicate that HMGA1 expression is increased in a substantial number of CCA specimens. HMGA1 further promotes CCA tumorigenicity and confers resistance to chemotherapy.

LTβR signalling preferentially accelerates oncogenic AKT-initiated liver tumours

OBJECTIVES

The relative contributions of inflammatory signalling and sequential oncogenic dysregulation driving liver cancer pathogenesis remain incompletely understood. Lymphotoxin-β receptor (LTβR) signalling is critically involved in hepatitis and liver tumorigenesis. Therefore, we explored the interdependence of inflammatory lymphotoxin signalling and specific oncogenic pathways in the progression of hepatic cancer.

DESIGN

Pathologically distinct liver tumours were initiated by hydrodynamic transfection of oncogenic V-Akt Murine Thymoma Viral Oncogene Homolog 1 (AKT)/β-catenin or AKT/Notch expressing plasmids. To investigate the relationship of LTβR signalling and specific oncogenic pathways, LTβR antagonist (LTβR-Fc) or agonist (anti-LTβR) were administered post oncogene transfection. Initiated livers/tumours were investigated for changes in oncogene expression, tumour proliferation, progression, latency and pathology. Moreover, specific LTβR-mediated molecular events were investigated in human liver cancer cell lines and through transcriptional analyses of samples from patients with intrahepatic cholangiocarcinoma (ICC).

RESULTS

AKT/β-catenin-transfected livers displayed increased expression of LTβ and LTβR, with antagonism of LTβR signalling reducing tumour progression and enhancing survival. Conversely, enforced LTβR-activation of AKT/β-catenin-initiated tumours induced robust increases in proliferation and progression of hepatic tumour phenotypes in an AKT-dependent manner. LTβR-activation also rapidly accelerated ICC progression initiated by AKT/Notch, but not Notch alone. Moreover, LTβR-accelerated development coincides with increases of Notch, Hes1, c-MYC, pAKT and β-catenin. We further demonstrate LTβR signalling in human liver cancer cell lines to be a regulator of Notch, pAKTser473 and β-catenin. Transcriptome analysis of samples from patients with ICC links increased LTβR network expression with poor patient survival, increased Notch1 expression and Notch and AKT/PI3K signalling.

CONCLUSIONS

Our findings link LTβR and oncogenic AKT signalling in the development of ICC.

Biliary cancer: Utility of next-generation sequencing for clinical management

BACKGROUND

Biliary tract cancers (BTCs) typically present at an advanced stage, and systemic chemotherapy is often of limited benefit.

METHODS

Hybrid capture-based comprehensive genomic profiling (CGP) was performed for 412 intrahepatic cholangiocarcinomas (IHCCAs), 57 extrahepatic cholangiocarcinomas (EHCCAs), and 85 gallbladder carcinomas (GBCAs). The mutational profile was correlated with the clinical outcome of standard and experimental therapies for 321 patients. Clinical variables, detected mutations, and administered therapies were correlated with overall survival (OS) in a Cox regression model.

RESULTS

The most frequent genetic aberrations (GAs) observed were tumor protein 53 (TP53; 27%), cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B; 27%), KRAS (22%), AT-rich interactive domain-containing protein 1A (ARID1A; 18%), and isocitrate dehydrogenase 1 (IDH1; 16%) in IHCCA; KRAS (42%), TP53 (40%), CDKN2A/B (17%), and SMAD4 (21%) in EHCCA; and TP53 (59%), CDKN2A/B (19%), ARID1A (13%), and ERBB2 (16%) in GBCA. Fibroblast growth factor receptor (FGFR; 11%) and IDH mutations (20%) were mostly limited to IHCCA but appeared to be mutually exclusive. In the IHCCA group, TP53 and KRAS mutations were associated significantly with poor OS, whereas FGFR2 mutations were associated with improved OS (P = .001), a younger age at onset, and female sex. IDH1/2 mutations were not prognostic. In a multivariate model, the effects of TP53 and FGFR GAs remained significant (P < .05). Patients with FGFR GAs had superior OS with FGFR-targeted therapy versus standard regimens (P = .006). Targeted therapy in IHCCA was associated with a numerical OS improvement (P = .07).

CONCLUSIONS

This is the largest clinically annotated data set of BTC cases with CGP and indicates the potential of CGP for improving outcomes. CGP should be strongly considered in the management of BTC patients. Cancer 2016;122:3838-3847. © 2016 American Cancer Society.

The effects of miR-1207-5p expression in peripheral blood on cisplatin-based chemosensitivity of primary gallbladder carcinoma

OBJECTIVE

The aim of this study was to investigate the association between miR-1207-5p expression in peripheral blood and the chemosensitivity of primary gallbladder carcinoma (PGBC).

METHODS

A total of 85 patients with PGBC undergoing preoperative chemotherapy were divided into effective (n=18) and ineffective (n=67) groups. Another 70 healthy individuals were selected as the control group. An miR-1207-5p mimic (mimic group), an inhibitor (inhibitor group), and a negative control (NC group) sequence were transfected into human gallbladder carcinoma GBC-SD cells. Real-time quantitative polymerase chain reaction was used to determine miR-1207-5p expression. After 48 hours of cisplatin treatment, CCK-8 method was used to detect cell proliferation and flow cytometry were performed to examine cell apoptosis.

RESULTS

miR-1207-5p expression in peripheral blood was significantly associated with tumor node metastasis staging of PGBC (P<0.05). Before chemotherapy, miR-1207-5p expression in patients was higher than in healthy individuals (P<0.05). After chemotherapy, the effective group had lower miR-1207-5p expression than the ineffective group (P<0.05). The rates of positive expression of Ki67 protein in the effective group were significantly lower than those in the ineffective group (P<0.05). Receiver operating characteristic curves showed that the area under curve, sensitivity, and specificity of miR-1207-5p used to diagnose PGBC were 0.898, 77.6%, and 97.1% at a cutoff of 1.470, respectively. After 48 hours of cisplatin treatment, compared with the NC group and nontransfected (non-T) group, the mimic group had decreased rates of cell inhibition and apoptosis, but the inhibitor group had increased rates (all P<0.05). The expression levels of caspase3 protein were increased in the mimic group and decreased in the inhibitor group. Cell survival rates in the mimic group at different time points after cisplatin treatment were significantly higher than the corresponding rates in the NC and non-T groups, whereas the cell survival rates in the inhibitor group were significantly lower than the rates in the NC and non-T groups (all P<0.05). The concentration and action time of cisplatin were negatively associated with the cell survival rate in each group (all P<0.05).

CONCLUSION

Cisplatin-based chemosensitivity of PGBC increased as expression of miR-1207-5p in peripheral blood declined. Thus, miR-1207-5p appears to be a promising and novel chemosensitizer for the treatment of PGBC.

Dual-modality imaging demonstrates the enhanced antitumoral effect of herpes simplex virus-thymidine kinase/ganciclovir plus gemcitabine combination therapy on cholangiocarcinoma

Herpes simplex virus-thymidine kinase/ganciclovir (HSV-TK/GCV) therapy is one of the most promising therapeutic strategies for the treatment of cholangiocarcinoma, which is the second most common hepatobiliary cancer. The aim of the present study was to evaluate the enhanced therapeutic effects of HSV-TK/GCV with gemcitabine on cholangiocarcinoma. QBC939 cholangiocarcinoma cells and mouse models of cholangiocarcinoma (established via tumor xenografts) received one of the following treatments: i) Gemcitabine therapy (3 µg/ml); ii) HSV-TK/GCV monotherapy; iii) HSV-TK/GCV + gemcitabine; and iv) control group, treated with phosphate-buffered saline. Cell proliferation was quantified using MTT assay and post-treatment tumor alterations were monitored using ultrasound imaging and optical imaging. For the in vitro experiments, the MTT assays demonstrated that the relative cell viabilities in the gene therapy, gemcitabine and gemcitabine + gene groups were 70.37±9.07, 52.64±8.28 and 34.21±6.63%, respectively. For the in vivo experiments, optical imaging indicated significantly decreased optical signals in the combination therapy group, as compared with the gemcitabine and gemcitabine + gene groups (1.68±0.74 vs. 2.27±0.58 and 2.87±0.82, respectively; Р<0.05). As demonstrated by ultrasound imaging, reduced tumor volumes were detected in the combination therapy group, as compared with the three control groups (114.32±17.17 vs. 159±23.74, 201.63±19.26 and 298.23±36.1 mm3, respectively; P<0.05). The results of the present study demonstrated that gemcitabine enhances the antitumoral effects of HSV-TK/GCV on cholangiocarcinoma, which may provide a novel therapeutic strategy for the management and treatment of cholangiocarcinoma using gemcitabine and gene therapy.

Recent advances for the treatment of pancreatic and biliary tract cancer after first-line treatment failure

Here, we evaluate clinical trials on chemotherapy for patients with pancreatic or biliary tract cancer after first-line treatment failure. Clinical trials on conventional and innovative medical treatments for progressive pancreatic and biliary cancer were analyzed. Metronomic chemotherapy, which consists of the administration of continuative low-dose of anticancer drugs, was also considered. A significant extension of overall survival was achieved with second-line, regimens in patients with gemcitabine-refractory pancreatic cancer. Moreover, many Phase II studies, including chemotherapy and target molecules and immunotherapy, have reported promising results, in both pancreatic and biliary cancer. However, data in these patients' setting are very heterogeneous, and only few randomized studies are available.

Liver cancer oncogenomics: opportunities and dilemmas for clinical applications

Primary liver cancers are among the most rapidly evolving malignant tumors worldwide. An underlying chronic inflammatory liver disease, which precedes liver cancer development for several decades and frequently creates a pro-oncogenic microenvironment, impairs progress in therapeutic approaches. Molecular heterogeneity of liver cancer is potentiated by a crosstalk between epithelial tumor and stromal cells that complicate translational efforts to unravel molecular mechanisms of hepatocarcinogenesis with a drugable intend. Next-generation sequencing has greatly advanced our understanding of cancer development. With regards to liver cancer, the unprecedented coverage of next-generation sequencing has created a detailed map of genetic alterations and identified key somatic changes such as CTNNB1 and TP53 as well as several previously unrecognized recurrent disease-causing alterations that could contribute to new therapeutic approaches. Importantly, these investigations indicate that a classical oncogene addiction cannot be assumed for primary liver cancer. Therefore, hepatocarcinogenesis can be considered a paradigm suitable for individualized medicine.

Impact of microenvironment and stem-like plasticity in cholangiocarcinoma: molecular networks and biological concepts

Clinical complexity, anatomic diversity and molecular heterogeneity of cholangiocarcinoma (CCA) represent a major challenge in the assessment of effective targeted therapies. Molecular and cellular mechanisms underlying the diversity of CCA growth patterns remain a key issue of clinical concern. Crucial questions comprise the nature of the CCA-origin, the initial target for cellular transformation as well as the relationship with the cancer stem cells (CSC) concept. Additionally, since CCA often develops in the context of an inflammatory milieu (cirrhosis and cholangitis), the stromal compartment or tumour microenvironment (TME) likely promotes initiation and progression of this malignancy, contributing to its heterogeneity. This review will emphasize the dynamic interplay between stem-like intrinsic and TME-extrinsic pathways, which may represent novel options for multi-targeted therapies in CCA.

Multimodal treatment strategies for advanced hilar cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary malignancy of the liver arising from malignant transformation and growth of biliary ductal epithelium. Approximately 50-70 % of CCAs arise at the hilar plate of the biliary tree, which are termed hilar cholangiocarcinoma (HC). Various staging systems are currently employed to classify HCs and determine resectability. Depending on the pre-operative staging, the mainstays of treatment include surgery, chemotherapy, radiation therapy, and photodynamic therapy. Surgical resection offers the only chance for cure of HC and achieving an R0 resection has demonstrated improved overall survival. However, obtaining longitudinal and radial surgical margins that are free of tumor can be difficult and frequently requires extensive resections, particularly for advanced HCs. Pre-operative interventions may be necessary to prepare patients for major hepatic resections, including endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography, and portal vein embolization. Multimodal therapy that combines chemotherapy with external beam radiation, stereotactic body radiation therapy, bile duct brachytherapy, and/or photodynamic therapy are all possible strategies for advanced HC prior to resection. Orthotopic liver transplantation is another therapeutic option that can achieve complete extirpation of locally advanced HC in judiciously selected patients following standardized neoadjuvant protocols.