GLI3-dependent repression of DR4 mediates hedgehog antagonism of TRAIL-induced apoptosis.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through its cognate receptors death receptor 4 (DR4) and death receptor 5 (DR5), preferentially in malignant cells. However, many malignant cells remain resistant to TRAIL cytotoxicity by poorly characterized mechanisms. Here, using cholangiocarcinoma cells, as a model for TRAIL resistance, we identified a role for the oncogenic Hedgehog (Hh)-GLI pathway in the regulation of TRAIL cytotoxicity. Blockade of Hh using pharmacological and genetic tools sensitizes the cells to TRAIL cytotoxicity. Restoration of apoptosis sensitivity coincided with upregulation of DR4 expression, while expression of other death effector proteins remained unaltered. Knockdown of DR4 mimics Hh-mediated resistance to TRAIL cytotoxicity. Hh regulates the expression of DR4 by modulating the activity of its promoter. Luciferase, chromatin immunoprecipitation and expression assays show that the transcription factor GLI3 binds to the DR4 promoter and Hh requires an intact GLI3-repression activity to silence DR4 expression. Finally, small interfering RNA (siRNA)-targeted knockdown of GLI3, but not GLI1 or GLI2, restores DR4 expression and TRAIL sensitivity, indicating that the Hh effect is exclusively mediated by this transcription factor. In conclusion, these data provide evidence of a regulatory mechanism, which modulates TRAIL signaling in cancer cells and suggest new therapeutic approaches for TRAIL-resistant neoplasms.

Prognostic role of vascular endothelial growth factor in hepatocellular carcinoma: systematic review and meta-analysis.

Hepatocellular carcinoma (HCC) is a highly vascular tumour that expresses vascular endothelial growth factor (VEGF). Various studies have evaluated the prognostic value of VEGF levels in HCC. Its overall test performance remains unclear, however. The aim was to perform a systematic review and meta-analysis of prognostic cohort studies evaluating the use of VEGF as a predictor of survival in patients with treated HCC. Eligible studies were identified through multiple search strategies. Studies were assessed for quality using the Newcastle-Ottawa Tool. Data were collected comparing disease-free and overall survival in patients with high VEGF levels as compared to those with low levels. Studies were pooled and summary hazard ratios were calculated. A total of 16 studies were included for meta-analysis (8 for tissue and 8 for serum). Methodological analysis indicated a trend for higher study quality with serum studies as compared to tissue-based investigations. Four distinct groups were pooled for analysis: tissue overall survival (n=251), tissue disease-free survival (n=413), serum overall survival (n=579), and serum disease-free survival (n=439). High tissue VEGF levels predicted poor overall (HR=2.15, 95% CI: 1.26-3.68) and disease-free (HR=1.69, 95% CI: 1.23-2.33) survival. Similarly, high serum VEGF levels predicted poor overall (HR=2.35, 95% CI: 1.80-3.07) and disease-free (HR=2.36, 95% CI 1.76-3.16) survival. A high degree of inter-study consistency was present in three of four groups analysed. Tissue and serum VEGF levels appear to have significant predictive ability for estimating overall survival in HCC and may be useful for defining prognosis in HCC.

Proteasome inhibition causes apoptosis of normal human plasma cells preventing alloantibody production.

Antibody production by normal plasma cells (PCs) against human leukocyte antigens (HLA) can be a major barrier to successful transplantation. We tested four reagents with possible activity against PCs (rituximab, polyclonal rabbit antithymocyte globulin (rATG), intravenous immunoglobulin (IVIG) and the proteasome inhibitor, bortezomib) to determine their ability to cause apoptosis of human bone marrow-derived PCs and subsequently block IgG secretion in vitro. IVIG, rituximab and rATG all failed to cause apoptosis of PCs and neither rituximab nor rATG blocked antibody production. In contrast, bortezomib treatment led to PC apoptosis and thereby blocked anti-HLA and antitetanus IgG secretion in vitro. Two patients treated with bortezomib for humoral rejection after allogeneic kidney transplantation demonstrated a transient decrease in bone marrow PCs in vivo and persistent alterations in alloantibody specificities. Total IgG levels were unchanged. We conclude that proteasome activity is important for PC longevity and its inhibition may lead to new techniques of controlling antibody production in vivo.

Surgery for cholangiocarcinoma: the role of liver transplantation.

UNLABELLED: Liver transplantation alone for unresectable hilar cholangiocarcinoma (CCA) is fraught with frequent recurrence and poor long-term survival. The Mayo Clinic developed a novel therapeutic protocol combining neoadjuvant chemoradiation and orthotopic liver transplantation (OLT) in 1993 to treat patients with unresectable hilar CCA or CCA arising in the setting of PSC. AIM: We recently reviewed our experience over the past 14 years with the specific aim to evaluate the long-term outcomes of CCA patients treated according to our study protocol. METHODS: We analyzed data from all patients enrolled in the Mayo Clinic liver transplant protocol since 1993. Statistical data analysis of recurrence and survival rates was performed using the Kaplan-Meier method. RESULTS: 148 patients were enrolled in the protocol. Of 90 patients who completed neoadjuvant therapy and subsequent OLT, 71 are alive and 19 have died--only 8 due to recurrent CCA. Nineteen patients are awaiting OLT and 39 were removed from the protocol owing to disease progression or death. Overall, 1-, 3-, and 5-year patient survival was 82%, 63%, and 55%, respectively; 1-, 3-, and 5-year survival after OLT was 90%, 80%, and 71%. CONCLUSIONS: Neoadjuvant chemoradiation and OLT achieves significantly lower recurrence and higher long-term survival rates than resection, OLT alone, or medical treatment in hilar CCA. Additional experience at independent transplant centers is necessary to confirm these encouraging results, address the role of neoadjuvant therapy and liver transplantation versus conventional resection, determine appropriate inclusion/exclusion criteria, and define the risk of disease progression while awaiting transplantation.

mir-29 regulates Mcl-1 protein expression and apoptosis.

Cellular expression of Mcl-1, an anti-apoptotic Bcl-2 family member, is tightly regulated. Recently, Bcl-2 expression was shown to be regulated by microRNAs, small endogenous RNA molecules that regulate protein expression through sequence-specific interaction with messenger RNA. By analogy, we reasoned that Mcl-1 expression may also be regulated by microRNAs. We chose human immortalized, but non-malignant, H69 cholangiocyte and malignant KMCH cholangiocarcinoma cell lines for these studies, because Mcl-1 is dysregulated in cells with the malignant phenotype. By in silico analysis, we identified a putative target site in the Mcl-1 mRNA for the mir-29 family, and found that mir-29b was highly expressed in cholangiocytes. Interestingly, mir-29b was downregulated in malignant cells, consistent with Mcl-1 protein upregulation. Enforced mir-29b expression reduced Mcl-1 protein expression in KMCH cells. This effect was direct, as mir-29b negatively regulated the expression of an Mcl-1 3' untranslated region (UTR)-based reporter construct. Enforced mir-29b expression reduced Mcl-1 cellular protein levels and sensitized the cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity. Transfection of non-malignant cells (that express high levels of mir-29) with a locked-nucleic acid antagonist of mir-29b increased Mcl-1 levels and reduced TRAIL-mediated apoptosis. Thus mir-29 is an endogenous regulator of Mcl-1 protein expression, and thereby, apoptosis.

Clinical Trial of the Pan-Caspase Inhibitor, IDN-6556, in Human Liver Preservation Injury.

Cold ischemia/warm reperfusion (CI/WR) injury remains a problem in liver transplantation. The aim of the current study was to assess the utility of the pan-caspase inhibitor IDN-6556 on CI/WR injury during human liver transplantation. This report is a post hoc analysis of a Phase II, multi-center, randomized, placebo-controlled, double-blinded, parallel group study. Subjects were assigned to four treatment groups: Group 1 (Organ storage/flush: Placebo-Recipient: Placebo); Group 2 (Organ storage/flush: 15 microg/mL-Recipient: Placebo); Group 3 (Organ storage/flush: 5 microg/mL-Recipient: 0.5 mg/kg); and Group 4 (Organ storage/flush: 15 microg/mL-Recipient: 0.5 mg/kg). Liver cell apoptosis was assessed by serum concentrations of the apoptosis-associated CK18Asp396 ('M30') neo-epitope, TUNEL assay and caspase 3/7 immunohistochemistry. Liver injury was assessed by serum AST/ALT determinations. Serum markers of liver cell apoptosis were reduced in all groups receiving drug as compared to placebo. However, TUNEL, caspase 3/7 positive cells and serum AST/ALT levels were only consistently reduced in Group 2 (drug exposed to organ only). This reduction in serum transaminases was significant and observed across the study. In conclusion, IDN-6556 when administered in cold storage and flush solutions during liver transplantation offers local therapeutic protection against CI/WR-mediated apoptosis and injury. However, larger studies are required to confirm these observations.

Lysophosphatidylcholine suppresses apoptotic cell death by inducing cyclooxygenase-2 expression via a Raf-1 dependent mechanism in human cholangiocytes.

PURPOSE: The high incidence of biliary tract carcinoma in patients with anomalous pancreaticobiliary ductal junction (APBDJ) implicates that a compositional alteration in bile may contribute to the genesis of this cancer. Lysophosphatidylcholine (LPC) is generated in the bile of these patients. Given the role of cyclooxygenase-2 (COX-2) in biliary tract carcinogenesis, we postulated that LPC induces COX-2 in cholangiocytes. METHODS: The effect of LPC on COX-2 expression in cholangiocytes was evaluated by immunoblot analysis, real-time PCR and reporter gene assay. Apoptosis was induced by TRAIL treatment, and quantified using DAPI staining. RESULTS: Lysophosphatidylcholine increased COX-2 protein expression in cholangiocytes in a concentration- and time-dependent manner. LPC-induced Raf-1 activation was responsible for this COX-2 induction. Accordingly, LPC increased COX-2 mRNA levels in a Raf-1 dependent manner by stabilizing COX-2 mRNA. Finally, LPC attenuated TRAIL-mediated apoptosis through a COX-2/PgE2 dependent mechanism. CONCLUSIONS: Collectively, these results implicate that LPC inhibits cholangiocyte apoptosis by inducing COX-2 expression via a Raf-1 dependent mechanism. This anti-apoptotic signaling may participate in biliary tract carcinogenesis in APBDJ patients, and therefore, its interruption may be a viable chemopreventative strategy.

TRAIL resistance results in cancer progression: a TRAIL to perdition?

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL, APO-2L) is a mediator of cell death that preferentially targets cancer cells. The potential of TRAIL as a chemotherapeutic agent is limited, however, because of the emergence of TRAIL resistance. Furthermore, recent studies have demonstrated that alternative TRAIL signaling is unmasked in TRAIL resistant cells. In these cells, the predominant effect of TRAIL receptor activation is the activation of nuclear factor-kappaB (NF-kappaB), which promotes tumor metastases and invasion. TRAIL resistance can occur at the level of the death inducing signaling complex via upregulation of cFLIP or via an increase in antiapoptotic proteins of the Bcl-2 family. A paradigm emerges from this information, that chemotherapy, targeting NF-kappaB, cFLIP, or antiapoptotic proteins of the Bcl-2 family, in combination with TRAIL maybe more rational than TRAIL therapy alone.

Review article: the modern diagnosis and therapy of cholangiocarcinoma.

Cholangiocarcinomas are epithelial neoplasms that originate from cholangiocytes and can occur at any level of the biliary tree. They are broadly classified into intrahepatic tumours, (extrahepatic) hilar tumours and (extrahepatic) distal bile duct tumours. In spite of well-understood predispositions, most cholangiocarcinomas arise in the absence of risk factors. In suspected cases, the diagnosis can be established with non-invasive imaging studies. Biliary invasion should be reserved for patients with obstruction. In high-risk patients, advanced cytological tests of aneuploidy (digital image analysis and fluorescent in situ hybridization) aid early diagnosis. In the absence of primary sclerosing cholangitis, curative surgical resection has 5-year survival rates of 2-43%, higher survival observed in patients with clear surgical margins and concomitant hepatic resection for hilar tumours. Patients with unresectable cholangiocarcinoma or pre-existing primary sclerosing cholangitis should be considered for liver transplantation with neoadjuvant chemoirradiation, in specialized centres.

Death by association: BH3 domain-only proteins and liver injury.

Apoptosis, a prominent form of cell death, is a prime feature of many acute and chronic liver diseases. Apoptosis requires mitochondrial dysfunction, which is regulated by proteins of the Bcl-2 family. Whether or not a cell should live or die is controlled by the interaction of multidomain Bcl-2 proteins with proapoptotic BH3 domain-only proteins of this family. Current models suggest multidomain, antiapoptotic Bcl-2 proteins prevent mitochondrial dysfunction by sequestering and/or preventing activation of its proapoptotic relatives. BH3-only proteins initiate cell death by neutralizing and or ligating multidomain prosurvival Bcl-2 proteins. Thus BH3 domain-only proteins are paramount in the apoptotic process as exemplified by the role of the BH3 domain-only protein Bid in liver injury. In this concise review, we will focus on how these BH3 domain-only proteins are regulated in the cell, their association with the Bcl-2 family of proteins, and finally, current information regarding their involvement in liver cell apoptosis and injury.

The relationship between apoptosis and non-alcoholic fatty liver disease: an evolutionary cornerstone turned pathogenic.

The data currently available favor a model for the pathogenesis of non-alcoholic fatty liver disease that is based on an apparent sequential relationship of intrahepatic apoptosis, inflammation and fibrogenesis. Based on both hepatic and peripheral insulin resistance, the hepatocellular accumulation of triglycerides, termed steatosis, initially leads to an altered metabolism of glucose and free fatty acids in the liver. In response, increased expression of death receptors in simple steatosis enhances the hepatocytes' susceptibility for pro-apoptotic stimuli, thus eliciting excessive hepatocyte apoptosis and inflammation. Evidence indicates that these processes, if prolonged, activate both hepatic stellate and Kupffer cells, thus leading to a vicious circle in which apoptosis, inflammation, cellular activation, and collagen deposition are upregulated even further.

Idiopathic benign biliary strictures in surgically resected patients with presumed cholangiocarcinoma.

OBJECTIVE: Distinguishing between malignant and benign biliary strictures remains problematic. The aim of this study was to compare and contrast the clinical features of patients with benign and malignant biliary strictures. METHODS: Medical records of patients who underwent surgical resection for presumed cholangiocarcinoma were reviewed. Immunohistochemistry for hypoxia inducible factor-1-alpha (HIF-1-alpha) was performed on all bile ductule samples. RESULTS: Twelve patients with benign strictures (group I) were compared to 26 patients with cholangiocarcinoma (group II). Group I was predominantly female (ratio 2: 1), (p<0.01), whereas the gender ratio was 1: 1 in patients in group II. Bismuth-Corlette type strictures in group I were more likely to be type I/II, whereas type III strictures predominated in group II. The CA 19-9 was <100 U/ml in 6 and >100 U/ml in 1 patient of group I and <100 in 13 and >100 in 11 patients in group II. Half of the patients in group I had positive immunoreactivity for HIF-1-alpha in bile ductules. CONCLUSION: Benign biliary strictures masquerading as cholangiocarcinomas occur more often in women, are less often Bismuth-Corlette type III, have serum CA 19-9 values <100 U/ml, and hypoxia may play a role in a subset of these strictures.

Cathepsin B inactivation attenuates hepatocyte apoptosis and liver damage in steatotic livers after cold ischemia-warm reperfusion injury.

Hepatic steatosis predisposes the liver to cold ischemia-warm reperfusion (CI/WR) injury by unclear mechanisms. Because hepatic steatosis has recently been associated with a lysosomal pathway of apoptosis, our aim was to determine whether this cell-death pathway contributes to CI/WR injury of steatotic livers. Wild-type and cathepsin B-knockout (Ctsb(-/-)) mice were fed the methionine/choline-deficient (MCD) diet for 2 wk to induce hepatic steatosis. Mouse livers were stored in the University of Wisconsin solution for 24 h at 4 degrees C and reperfused for 1 h at 37 degrees C in vitro. Immunofluorescence analysis of the lysosomal enzymes cathepsin B and D showed a punctated intracellular pattern consistent with lysosomal localization in wild-type mice fed a standard diet after CI/WR injury. In contrast, cathepsin B and D fluorescence became diffuse in livers from wild-type mice fed MCD diet after CI/WR, indicating that lysosomal permeabilization had occurred. Hepatocyte apoptosis was rare in both normal and steatotic livers in the absence of CI/WR injury but increased in wild-type mice fed an MCD diet and subjected to CI/WR injury. In contrast, hepatocyte apoptosis and liver damage were reduced in Ctsb(-/-) and cathepsin B inhibitor-treated mice fed the MCD diet following CI/WR injury. In conclusion, these findings support a prominent role for the lysosomal pathway of apoptosis in steatotic livers following CI/WR injury.

Phase II study of the efficacy and safety of cisplatin-epinephrine injectable gel administered to patients with unresectable hepatocellular carcinoma.

PURPOSE: To study the efficacy and safety of percutaneous cisplatin-epinephrine (CDDP-EPI) injectable gel in patients with localized unresectable hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Eligible patients had histologically proven HCC, no prior treatment except for surgery, and no more than three tumors (each measured < or = 7 cm, total tumor volume < or = 200 cm(3)). They were treated percutaneously under ultrasound or computed tomography (CT) guidance, with up to 10 mL of CDDP-EPI gel (1 mL contains 4 mg of CDDP and 0.1 mg of EPI) per treatment and four treatments in 6 weeks to a maximum of eight treatments. The primary end points were tumor response, defined by change of percentage of tumor necrosis according to CT criteria, and safety. Survival parameters were secondary end points. RESULTS: From June 1997 to April 2000, 58 patients (median age, 65 years) entered the study. All patients were assessable for safety, and 51 were assessable for efficacy. The median number of treatments was four (range, one to eight treatments). Objective response rate was 53% (27 of 51 patients), including 16 complete and 11 partial responses. Of the 27 responders, 14 (52%) subsequently developed progressive disease, but in most of them (93%), a new tumor arose at untreated liver sites. Median survival was 27 months (range, 18.4 to 35.7 months). The 1-, 2-, and 3-year survival rates were 79%, 56%, and 14% respectively. The procedure was well tolerated with only minor side effects. CONCLUSION: Percutaneous local ablation with CDDP-EPI injectable gel can induce significant tumor necrosis and local control for localized unresectable HCC, and the treatment is well tolerated.

Cathepsin B knockout mice are resistant to tumor necrosis factor-alpha-mediated hepatocyte apoptosis and liver injury: implications for therapeutic applications.

Tumor necrosis factor-alpha (TNF-alpha) contributes to liver injury by inducing hepatocyte apoptosis. Recent evidence suggests that cathepsin B (cat B) contributes to TNF-alpha-induced apoptosis in vitro. The aim of the present study was to determine whether cat B contributes to TNF-alpha-induced hepatocyte apoptosis and liver injury in vivo. Cat B knockout (catB(-/-)) and wild-type (catB(+/+)) mice were first infected with the adenovirus Ad5I kappa B expressing the I kappa B superrepressor to inhibit nuclear factor-kappa B-induced survival signals and then treated with murine recombinant TNF-alpha. Massive hepatocyte apoptosis with mitochondrial release of cytochrome c and activation of caspases 9 and 3 was detected in catB(+/+) mice 2 hours after the injection of TNF-alpha. In contrast, significantly less hepatocyte apoptosis and no detectable release of cytochrome c or caspase activation occurred in the livers of catB(-/-) mice. By 4 hours after TNF-alpha injection, only 20% of the catB(+/+) mice were alive as compared to 85% of catB(-/-) mice. Pharmacological inhibition of cat B in catB(+/+) mice with L-3-trans-(propylcarbamoyl)oxirane-2-carbonyl-L-isoleucyl-L-proline (CA-074 Me) also reduced TNF-alpha-induced liver damage. The present data demonstrate that a cat B-mitochondrial apoptotic pathway plays a pivotal role in TNF-alpha-induced hepatocyte apoptosis and liver injury.

Bid antisense attenuates bile acid-induced apoptosis and cholestatic liver injury.

Bile acids cause liver injury during cholestasis by inducing hepatocyte apoptosis by both Fas-dependent and -independent mechanisms. However, the Fas-independent apoptosis also appears to be death receptor-mediated. Because death receptor-mediated apoptosis in hepatocytes requires proapoptotic Bcl-2 BH3 domain only protein Bid, we postulated that Fas-independent but death receptor-mediated bile acid cytotoxicity would be Bid-dependent. We used Fas-deficient lymphoproliferative (lpr) mouse hepatocytes for these studies, and inhibited Bid expression using an antisense approach. Glychochenodeoxycholate (GCDC) was used to induce apoptosis. Bid cleavage and translocation to mitochondria was observed in GCDC-treated cells as assessed by immunoblot analysis and confocal imaging of Bid-green fluorescent protein, respectively. Bid translocation to mitochondria was associated with cytochrome c release. A Bid antisense 2'-MOE modified oligonucleotide inhibited Bid expression in hepatocytes and markedly attenuated hepatocytes apoptosis by GCDC. Treatment of lpr mice with Bid antisense also ameliorated liver injury following bile duct ligation of the mice, a model of extrahepatic cholestasis. These results suggest that bile acid cytotoxicity is Bid-dependent despite the absence of Fas. Bid antisense therapy is a promising approach for the treatment of cholestatic liver injury.