Expression of c-kit receptor in human cholangiocarcinoma and in vivo treatment with imatinib mesilate in chimeric mice

Outcome of Localized Bile Duct Carcinoma in Six Dogs Treated with Liver Lobectomy

The prognosis for bile duct carcinoma in dogs is generally believed to be poor. However, only a few studies have evaluated the postoperative outcomes in such cases. The objective of this case series was to describe the postoperative outcomes of localized intrahepatic bile duct carcinoma in dogs. The electronic medical records of 16 dogs with bile duct carcinoma were reviewed, and 6 dogs were included in the study. All cases were diagnosed as bile duct carcinoma using postoperative pathology, and five of them had already been diagnosed using preoperative core biopsy. The tumors in all of the dogs were confirmed as completely resected on histopathological examination. Two dogs received toceranib following the surgery. The median follow-up time was 693 days (range, 420-1386 days), with a median survival time of 894 days (range, 420-1386 days). Local recurrence or distant metastases were detected in two of the six dogs (33%) on 354 and 398 days following surgery, respectively. The median progression-free survival was 492 days (range, 354-1386 days). In conclusion, dogs with localized intrahepatic bile duct carcinoma had a good prognosis following complete surgical resection.

The effects of Sorafenib and Natural killer cell co-injection in combinational treatment of hepatocellular carcinoma; an in vivo approach

BACKGROUND

Natural killer cells (NKC) and Sorafenib (Sor) are two important agents for the treatment of hepatocellular carcinoma (HCC). Over the past decade, the interaction of Sor and NKC against HCC has been widely challenging. This study aimed to assess the efficacy of NKC & Sor for the treatment of HCC in vivo.

METHODS

Subcutaneous xenograft models of HCC were established in nude mice. For safety assessment of treatment, the kidney and liver functions were analyzed. Paraffin embedded tumor sections were histopathologically studied and immunohistochemistry (IHC) tests were done to evaluate the angiogenesis (CD34) and proliferation (Ki67) indexes. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to identify the tumor cells undergoing apoptosis. The serum levels of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were measured by enzyme-linked immunosorbent assay (ELISA) and expression levels of major inflammatory cytokines and cytoplasmic granules in xenograft HCC were quantified using real-time PCR.

RESULTS

NKC & Sor significantly inhibited necrosis and apoptosis in tumor cells and increased angiogenesis and proliferation of HCC compared to the monotherapy of NKC or Sor alone. The serum levels of TNF-α, IFN-γ as well as the expression levels of TNF-α, IFN-γ, interleukins (ILs)-1, 6, 10, granzyme-B and perforin in the xenograft HCC tissues of the treated mice with NKC & Sor were significantly lower than those of treated with NKC or Sor alone.

CONCLUSION

Therapy with the specific dosage of NKC & Sor could not inhibit the HCC xenograft growth rate through a synergistic effect in a mouse model of HCC.

Characterization of the erythropoietin/erythropoietin receptor axis in a rat model of liver damage and cholangiocarcinoma development

It has been recently shown that the biological effects of erythropoietin (EPO) are not limited to the hematopoietic compartment but, as pleiotropic glycoprotein, this hormone can exert pro-angiogenic and tissue-protective functions also in a wide range of non-hematopoietic organs. The role of EPO and the effective functionality of its receptor in solid tumors are still a controversial point of debate. In the present work we analyzed the gene expression of EPO and its cognate receptor (EpoR) in a rat model of thioacetamide-induced damage and tumor. An analysis of the EPO/EpoR axis was also performed on human cholangiocarcinoma (CC) cell lines. A progressive increase of EPO and EpoR mRNA can already be observed during the fibrotic–cirrhotic development with a peak of expression rising at tumor formation (24.7 ± 9.9-fold increase and 15.5 ± 1.1-fold increase, respectively, for the two genes). Co-localization studies by immunofluorescence revealed hepatocytes in the regenerative cirrhotic nodules (Hep Par-1⁺) and in the dysplastic bile duct cells (CK19⁺) as the major EPO producers in this specific condition. The same cell populations, together with endothelial cells, exhibited an increased expression of EpoR, although all the non-parenchymal cell populations in the liver exhibited modest basal mRNA levels. Challenging human CC cells, Mz-Cha-2, with a combination of EPO and SCF resulted in a synergistic effect on the gene expression of EPO, CyclinD1 and PCNA. This study suggests that the autocrine and paracrine release of endogenous EPO in the microenvironment may contribute to the development and maintenance of the CC possibly in cooperation with other signaling pathways.

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.

Imatinib mesylate improves liver regeneration and attenuates liver fibrogenesis in CCL4-treated mice

BACKGROUNDS

Imatinib mesylate (STI-571), a tyrosine kinase inhibitor, has previously been demonstrated to attenuate liver fibrogenesis through inhibition of the activation of hepatic stellate cells (HSCs) in CCL(4)-treated rat models.

AIMS

This study aimed to further evaluate the role of STI-571 in liver regeneration.

MATERIALS AND METHODS

All animals were divided into four groups, and mice were treated with or without CCL(4) and STI-571 (n = 6 for each group).

RESULTS

Activated cultured HSCs in vitro with STI-571 administration showed increased apoptosis and reduced proliferation, as determined by flow cytometric analysis, 3-(4, 5-cimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay, and confocal microscopy. STI-571 treatment attenuated liver fibrosis in vivo, as was evident in the results of histology, mRNA level, and expression analysis of smooth muscle actin and type I collagen. Mice treated with STI-571 had increased liver weight ratio and the improvement in liver regeneration was compatible with the change of serum interleukin 6 levels (p < 0.05). Further, increased apoptosis and a reduced proliferation were observed in the CCL(4)-treated mice after STI-571 treatment based on the immunohistochemical staining of Annexin V, phosphorylated STAT3, and PCNA.

CONCLUSION

STI-571 treatment effectively attenuated liver fibrogenesis and improved in liver regeneration in vivo and induced apoptosis in HSCs both in vitro and in vivo.

Nuclear expression of S100A4 calcium-binding protein increases cholangiocarcinoma invasiveness and metastasization

Cholangiocarcinoma (CCA) carries a severe prognosis because of its strong invasiveness and early metastasization. In several patients, otherwise eligible for surgical resection, micrometastasis are already present at the time of surgery. The mechanisms responsible for CCA invasiveness are unclear. S100A4, a member of the S100 family of small Ca(2+)-binding proteins, is expressed in mesenchymal cells, regulates cell motility in several cell types, and is expressed in some epithelial cancers. Thus, we aimed to study the role of S100A4 in CCA invasiveness and metastasization. The expression of S100A4 was studied by immunohistochemistry in 93 human liver samples of CCA patients undergoing surgical resection and correlated with metastases development (67 cases) and patient survival following surgery using log rank tests and multivariate analysis. S100A4 expression was studied in EGI-1 and TFK-1, human CCA cell lines with and without nuclear S100A4 expression, respectively. Metastatic properties of CCA cells were assessed by xenotransplantation in severe combined immunodeficiency (SCID) mice after transduction with lentiviral vectors encoding firefly luciferase gene. Proliferation, motility (wound healing), invasiveness (Boyden chamber), and metalloproteinases (MMPs) secretion were studied in CCA cells, with or without lentiviral silencing of S100A4. Nuclear expression of S100A4 by neoplastic ducts was a strong predictor of metastasization and reduced survival after resection (P < 0.01). EGI-1 CCA cells showed stronger metastatic properties than TFK-1 when xenotransplanted in SCID mice. S100A4-silenced EGI-1 cells showed significantly reduced motility, invasiveness, and MMP-9 secretion in vitro, without changes in cell proliferation.

CONCLUSION

Nuclear S100A4 identifies a subset of CCA patients with a poor prognosis after surgical resection. Nuclear expression of S100A4 increases CCA cells invasiveness and metastasization, indicating that S100A4 may also represent a potential therapeutic target.

Emerging drugs for biliary cancer

Biliary cancer comprise carcinoma of the gallbladder as well as the intrahepatic, hilar and extrahepatic bile ducts. Furthermore, many different etiologies and risk factors are contributing to the inhomogeneity of this disease. It is often diagnosed at an advanced stage when potentially curative resection is not feasible. Due to the lack of randomised Phase III studies, there is no standard regimen for chemotherapy in biliary cancer. Recent investigations into the underlying molecular mechanisms involved in biliary carcinogenesis and tumour growth have contributed greatly to our understanding of biliary cancer. Through a better understanding of these mechanisms, improved and more specific diagnostic, therapeutic and preventive strategies may be developed. Although fluoropyrimidines and gemcitabine remain the backbone of routine chemotherapy in advanced disease, new agents such as epidermal growth factor receptor blockers and angiogenesis inhibitors may hold promise for improving the outcome for patients with biliary cancer.

Inhibition of histone deacetylase for the treatment of biliary tract cancer: A new effective pharmacological approach

AIM: To investigate in vitro and in vivo therapeutic effects of histone deacetylase inhibitors NVP-LAQ824 and NVP-LBH589 on biliary tract cancer.

METHODS: Cell growth inhibition by NVP-LAQ824 and NVP-LBH589 was studied in vitro in 7 human biliary tract cancer cell lines by MTT assay. In addition, the anti-tumoral effect of NVP-LBH589 was studied in a chimeric mouse model. Anti-tumoral drug mechanism was assessed by immunoblotting for acH4 and p21^WAF-1/CIP-1, PARP assay, cell cycle analysis, TUNEL assay, and immunhistochemistry for MIB-1.

RESULTS: In vitro treatment with both compounds significantly suppressed the growth of all cancer cell lines [mean IC₅₀ (3 d) 0.11 and 0.05 μmol/L, respectively], and was associated with hyperacetylation of nucleosomal histone H4, increased expression of p21^WAF-1/CIP-1, induction of apoptosis (PARP cleavage), and cell cycle arrest at G2/M checkpoint. After 28 d, NVP-LBH589 significantly reduced tumor mass by 66% (bile duct cancer) and 87% (gallbladder cancer) in vivo in comparison to placebo, and potentiated the efficacy of gemcitabine. Further analysis of the tumor specimens revealed increased apoptosis by TUNEL assay and reduced cell proliferation (MIB-1).

CONCLUSION: Our findings suggest that NVP-LBH589 and NVP-LAQ824 are active against human biliary tract cancer in vitro. In addition, NVP-LBH589 demonstrated significant in vivo activity and potentiated the efficacy of gemcitabine. Therefore, further clinical evaluation of this new drug for the treatment of biliary tract cancer is recommended.

Irinotecan With 5-FU/FA in Advanced Biliary Tract Adenocarcinomas

OBJECTIVES

Biliary cancer has a poor prognosis and lacks a standard palliative chemotherapy. The purpose of this prospective single-arm phase II study was to determine the activity and tolerability of irinotecan, 5-fluorouracil, and folinic acid in advanced biliary cancer.

PATIENTS AND METHODS

Patients with inoperable intrahepatic cholangiocarcinoma (ICC) or gallbladder cancer (GBC) and no prior chemotherapy were eligible. Irinotecan 80 mg/m2, followed by folinic acid 500 mg/m2 and 5-FU 2000 mg/m2 infused over 24 hours (Fufiri) were administered weekly 6 times, every 8 weeks. The primary endpoint was response rate, and secondary endpoints were overall survival (OS), progression-free survival (PFS), and toxicity.

RESULTS

Seventeen patients with ICC and 13 patients with GBC were enrolled. All patients were evaluable for safety. WHO grade 3/4 drug-related adverse events occurred in 8 patients (27%), consisting of diarrhea and leukopenia in 5 and 3 patients, respectively. One patient with diarrhea grade 4 finally succumbed to sepsis. Objective response rate was 10% (95% confidence interval, 2.1%-26.5%), with an additional 10% of patients showing stable disease. Median overall survival was 166 days and 273 days, and median progression-free survival was 84 days and 159 days for ICC and GBC, respectively.

CONCLUSIONS

Fufiri is a well-tolerated regimen in patients with ICC and GBC but has only modest activity in advanced biliary tract cancer.

Establishment of a novel orthotopic xenograft model of human gallbladder carcinoma

OBJECTIVE

Gallbladder cancer is characterized by high morbidity and mortality. An appropriate human xenograft animal model could serve as a research tool to investigate new therapeutic strategies.

SUMMARY BACKGROUND DATA

To date, the few reports describing a xenograft animal model showed significant limitations. We improved a murine orthotopic human xenotransplantation model by implanting human gallbladder carcinoma cells directly into the lumen of the gallbladder.

METHODS

Mz-ChA-1 cells were orthotopically injected into the gallbladder of Severe Combined Immune Deficiency (SCID) beige mice inducing the growth of solid tumors. The natural course of the disease, tumor growth, and metastases were analyzed. The cytotoxic drug gemcitabine was tested in vitro and in vitro.

RESULTS

All animals revealed solid tumors in the inoculated area with liver infiltration. The median tumor volume in the untreated group was significantly higher than in the gemcitabine-treated group. Immunohistochemical staining revealed expression of human cytokeratin 7 and cytokeratin 8. To analyze tumor cell proliferation, the tumors were stained for the antigen Ki-67, and labeling indices were calculated for both groups. Animals receiving gemcitabine treatment showed significantly lower mean labeling indices. In vitro investigation revealed a significant reduction of DNA synthesis. DNA fragmentation, as a measure of apoptosis, was elevated by roughly 20% within 24 h of treatment. With this, we successfully established an orthotopic xenotransplant animal model and investigated the in vitro and in vivo effects of gemcitabine in human xenografted Mz-ChA-1 gallbladder adenocarcinoma.

CONCLUSION

This model resembles the clinical situation as closely as possible and offers a relevant option for the preclinical testing of new therapeutic strategies.

Novel targeted approaches to treating biliary tract cancer: the dual epidermal growth factor receptor and ErbB-2 tyrosine kinase inhibitor NVP-AEE788 is more efficient than the epidermal growth factor receptor inhibitors gefitinib and erlotinib

Aberrant activation of the epidermal growth factor receptor is frequently observed in neoplasia, notably in tumors of epithelial origin. Attempts to treat such tumors with epidermal growth factor receptor antagonists resulted in remarkable success in recent studies. Little is known, however, about the efficacy of this therapy in biliary tract cancer. Protein expression of epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 was assessed in seven human biliary tract cancer cell lines by immunoblotting. In addition, histological sections from 19 patients with extrahepatic cholangiocarcinoma were analyzed for epidermal growth factor receptor, ErbB-2 and vascular endothelial growth factor receptor-2 expression by immunohistochemistry. Moreover, we sequenced the cDNA products representing the entire epidermal growth factor receptor coding region of the seven cell lines, and searched for genomic epidermal growth factor receptor amplifications and polysomy by fluorescence in-situ hybridization. Cell growth inhibition by gefitinib erlotinib and NVP-AEE788 was studied in vitro by automated cell counting. In addition, the anti-tumoral effect of erlotinib and NVP-AEE788 was studied in a chimeric mouse model. The anti-tumoral drug mechanism in this model was assessed by MIB-1 antibody staining, terminal deoxynucleotidyl transfer-mediated dUTP nick end-labelling assay, von Willebrand factor staining, and immunoblotting for p-p42/44 (p-Erk1/2, p-MAPK) and p-AKT. Immunoblotting revealed expression of epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 in all biliary tract cancer cell lines. EGFR was detectable in six of 19 (32%) extrahepatic human cholangiocarcinoma tissue samples, ErbB-2 in 16 of 19 (84%), and vascular endothelial growth factor receptor-2 in nine of 19 (47%). Neither epidermal growth factor receptor mutations nor amplifications or polysomy were found in the seven biliary tract cancer cell lines. Gefitinib, erlotinib and NVP-AEE788 caused a significant growth inhibition in vitro; however, there was a significant difference in efficacy (NVP-AEE788>erlotinib>gefitinib). After 14 days of in-vivo treatment, using the chimeric mouse model, tumors had a significantly reduced volume and mass after NVP-AEE788, but not after erlotinib treatment, as compared with placebo. Reduction of proliferation (signalling via the mitogen-activated protein kinase pathway), induction of apoptosis and inhibition of angiogenesis were the main mechanisms of drug action. No significant reduction of anti-apoptotic AKT phosphorylation, however, occurred, which may be a possible counter mechanism of the tumor. Epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 expression was detectable in biliary tract cancer, and receptor inhibition exerts marked effects on tumor growth in vitro and in vivo, which was strongest for the dual EGFR/ErbB-2 inhibitor NVP-AEE788. Therefore, further clinical evaluation of this new drug for the treatment of biliary tract cancer is recommended.