mTOR Inhibition Is Most Beneficial After Liver Transplantation for Hepatocellular Carcinoma in Patients With Active Tumors

OBJECTIVE

The aim of this study was to evaluate the survival benefit of sirolimus in patients undergoing liver transplantation (LT) for hepatocellular carcinoma (HCC) (exploratory analysis of the SiLVER-trial).

SUMMARY AND BACKGROUND DATA

Patients receiving LT) for HCC are at a high risk for tumor recurrence. Calcineurin inhibitors have shown evidence to promote cancer growth, whereas mammalian target of rapamycin (mTOR) inhibitors like sirolimus have anticancer effects. In the SiLVER-trial (Clinicaltrials.gov: NCT00355862), the effect of sirolimus on the recurrence of HCC after LT was investigated in a prospective randomized trial. Although the primary endpoint of improved disease-free survival (DFS) with sirolimus was not met, outcomes were improved for patients in the sirolimus-treatment arm in the first 3 to 5 years. To learn more about the key variables, a multivariate analysis was performed on the SiLVER-trial data.

PATIENTS AND METHODS

Data from 508 patients of the intention-to-treat analysis were included in exploratory univariate and multivariate models for overall survival (OS), DFS and a competing risk analysis for HCC recurrence.

RESULTS

Sirolimus use for ≥3 months after LT for HCC independently reduced the hazard for death in the multivariate analysis [hazard ratio (HR): 0.7 (95% confidence interval, CI: 0.52-0.96, P = 0.02). Most strikingly, patients with an alpha-fetoprotein (AFP) ≥10 ng/mL and having used sirolimus for ≥3 months, benefited most with regard to OS, DFS, and HCC-recurrence (HR: 0.49-0.59, P = 0.0079-0.0245).

CONCLUSIONS

mTOR-inhibitor treatment with sirolimus for ≥3 months improves outcomes in LT for HCC, especially in patients with AFP-evidence of higher tumor activity, advocating particularly for mTOR inhibitor use in this subgroup of patients.

CLINICAL TRIAL REGISTRATION

EudraCT: 2005-005362-36 CLINICALTRIALS.GOV:: NCT00355862.

Impact of Inter-Laboratory Variability on Model of End-Stage Liver Disease (MELD) Score Calculation

BACKGROUND The model for end-stage liver disease (MELD) is a laboratory-based scoring system for assessing the severity of liver disease. Since 16 December 2006, MELD-based organ allocation for liver transplantation (LT) has been established in Germany to prioritize the sickest patients. The present study was designed to evaluate the effect of using different laboratories on the calculated MELD score, despite the use of mandatory round-robin testing for comparable of inter-laboratory results. MATERIAL AND METHODS Blood samples were taken from 10 patients with liver disease. Bilirubin, creatinine, and INR were measured in 6 different laboratories. The patients' MELD scores were calculated and the inter-laboratory variability was compared. RESULTS The highest discrepancy between the laboratories was 5 MELD score points and the highest inter-laboratory difference for bilirubin, INR, and creatinine was 4.6, 1.2, and 0.99 mg/dl, respectively. Pairwise comparison of the laboratory values showed a significant inter-laboratory difference (p<0.05). CONCLUSIONS Results clearly demonstrate, for the first time, that liver allocation for LT in Germany is based on nationwide noncomparable laboratory readouts for the MELD score.

Resminostat plus sorafenib as second-line therapy of advanced hepatocellular carcinoma - The SHELTER study

BACKGROUND & AIMS

No established therapies for patients with hepatocellular carcinoma (HCC) and progression on first-line sorafenib treatment currently exist. This phase I/II trial investigated safety, pharmacokinetics and potential biomarkers of the histone deacetylase inhibitor resminostat and a combination therapy with resminostat and sorafenib.

METHODS

Patients with HCC and radiologically confirmed progression on sorafenib were treated in an exploratory, multi-center, open-label, uncontrolled, non-randomized, parallel group phase I/II study. In the combination group (n=38) four dose levels ranged from daily 200 to 600mg resminostat plus 400 to 800mg sorafenib. The monotherapy group (n=19) received 600mg resminostat.

RESULTS

57 patients received treatment. Most common adverse events were gastrointestinal disorders, thrombocytopenia and fatigue. Median maximal histone deacetylase inhibition and highest increase in H4-acetylation matched Tmax of resminostat. Sorafenib or the Child-Pugh score did not affect typical pharmacokinetics characteristics of resminostat. Efficacy assessment as progression-free survival-rate after 6 treatment cycles (12weeks, primary endpoint) was 12.5% for resminostat and 62.5% for resminostat plus sorafenib. Median time to progression and overall survival were 1.8 and 4.1months for resminostat and 6.5 and 8.0months for the combination, respectively. Zinc finger protein 64 (ZFP64) baseline expression in blood cells was found to correlate with overall survival.

CONCLUSIONS

The combination of sorafenib and resminostat in HCC patients was safe and showed early signs of efficacy. Sorafenib did not alter the pharmacokinetic profile of resminostat or its histone deacetylase inhibitory activity in vivo. A prognostic and potentially predictive role of ZFP64 for treatment with resminostat should be further investigated in HCC and possibly other cancer indications.

LAY SUMMARY

No established therapy for patients with advanced hepatocellular carcinoma and progression under first-line systemic treatment with sorafenib currently exists. Epigenetic modulation by inhibition of histone deacetylases might be able to overcome therapy resistance. This exploratory phase I/II clinical study in patients with radiologically confirmed progression under first-line treatment with sorafenib investigated the histone deacetylases inhibitor resminostat as single agent or in combination with continued application of sorafenib.

CLINICAL TRIAL REGISTRATION

The clinical trial has been registered at www.clinicaltrials.gov as NCT00943449.

Cancer cell-autonomous TRAIL-R signaling promotes KRAS-driven cancer progression, invasion, and metastasis

Many cancers harbor oncogenic mutations of KRAS. Effectors mediating cancer progression, invasion, and metastasis in KRAS-mutated cancers are only incompletely understood. Here we identify cancer cell-expressed murine TRAIL-R, whose main function ascribed so far has been the induction of apoptosis as a crucial mediator of KRAS-driven cancer progression, invasion, and metastasis and in vivo Rac-1 activation. Cancer cell-restricted genetic ablation of murine TRAIL-R in autochthonous KRAS-driven models of non-small-cell lung cancer (NSCLC) and pancreatic ductal adenocarcinoma (PDAC) reduces tumor growth, blunts metastasis, and prolongs survival by inhibiting cancer cell-autonomous migration, proliferation, and invasion. Consistent with this, high TRAIL-R2 expression correlates with invasion of human PDAC into lymph vessels and with shortened metastasis-free survival of KRAS-mutated colorectal cancer patients.

Pancreatic Atrophy in Hepatocellular Carcinoma Patients Receiving Long-Term Treatment with Sorafenib

OBJECTIVE

To date, sorafenib is the only approved systemic therapy for advanced hepatocellular carcinoma (HCC). Pancreatic atrophy has recently been reported in 2 patients as a novel side effect after long-term sorafenib treatment.

METHODS

We retrospectively analyzed clinical and radiological data of patients with advanced HCC with long-term treatment of sorafenib (median 279 days, range 153-826 days). Pancreata were semi-manually segmented section by section to calculate the pancreas volumes before and under sorafenib treatment.

RESULTS

Sorafenib reduced pancreatic volume in 18/19 (95%) HCC patients with a mean pancreatic volume loss of 25% (p = 0.002). Pancreatic volume loss depended on the dose (r = 0.36) and exposure time of sorafenib (r = 0.35) and was detectable as early as after 3 months of sorafenib treatment and already after a cumulative sorafenib dose of <100 g. Median overall survival was 13.2 months (range 7.8-31.3 months) but did not correlate with sorafenib-induced pancreatic volume reduction (hazard ratio 1.002, 95% confidence interval 0.981-1.060, p = 0.24).

CONCLUSION

We could confirm pancreatic atrophy as a novel adverse event of sorafenib therapy in HCC patients, correlating with sorafenib dose and exposure time.

CYP3A activity in severe liver cirrhosis correlates with Child-Pugh and model for end-stage liver disease (MELD) scores

AIMS

Impaired liver function often necessitates drug dose adjustment to avoid excessive drug accumulation and adverse events, but a marker for the extent of the required adjustment is lacking. The aim of this study was to investigate whether Child-Pugh (CP) and model for end-stage liver disease (MELD) scores correlate with drug clearance.

METHODS

Midazolam was used as a CYP3A probe and its pharmacokinetics were analyzed in 24 patients with mild to severe liver cirrhosis (n = 4, 10 and 10 with CP class A, B and C, respectively) and six patients without liver disease.

RESULTS

Both scores correlated well with unbound midazolam clearance (CLu ), unbound midazolam fraction and half-life (all P < 0.01), whereas the unbound steady-state volume of distribution was not significantly changed. In patients with severe liver cirrhosis unbound midazolam clearance was only 14% of controls (CP C: CLu = 843 ± 346 l  h(-1), MELD ≥ 15: CLu = 805 ± 474 l  h(-1), controls: CLu = 5815 ± 2649 l  h(-1), P < 0.01).

CONCLUSION

The correlation with unbound midazolam clearance suggests that either score predicts the metabolic capacity of CYP3A, the most relevant drug metabolizing enzyme subfamily in humans.

Bortezomib sensitizes primary meningioma cells to TRAIL-induced apoptosis by enhancing formation of the death-inducing signaling complex

A meningioma is the most common primary intracranial tumor in adults. Here, we investigated the therapeutic potential of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in 37 meningiomas. Freshly isolated primary meningioma cells were treated with TRAIL with or without different sensitizing protocols, and apoptotic cell death was then quantified. Mechanisms of TRAIL sensitization were determined by a combination of Western blotting, flow cytometry, receptor complex immunoprecipitation, and siRNA-mediated knockdown experiments. Tumor necrosis factor-related apoptosis-inducing ligand receptor expression was analyzed using immunohistochemistry and quantified by an automated software-based algorithm. Primary tumor cells from 11 (29.7%) tumor samples were sensitive to TRAIL-induced apoptosis, 12 (32.4%) were intermediate TRAIL resistant, and 14 (37.8%) were completely TRAIL resistant. We tested synergistic apoptosis-inducing cotreatment strategies and determined that only the proteasome inhibitor bortezomib potently enhanced expression of the TRAIL receptors TRAIL-R1 and/or TRAIL-R2, the formation of the TRAIL death-inducing signaling complex, and activation of caspases; this treatment resulted in sensitization of all TRAIL-resistant meningioma samples to TRAIL-induced apoptosis. Bortezomib pretreatment induced NOXA expression and downregulated c-FLIP, neither of which caused the TRAIL-sensitizing effect. Native TRAIL receptor expression could not predict primary TRAIL sensitivity. This first report on TRAIL sensitivity of primary meningioma cells demonstrates that TRAIL/bortezomib cotreatment may represent a novel therapeutic option for meningiomas.

Radiological monitoring of the treatment of solid tumors in practice

PURPOSE

Thanks to advances in cancer therapy, the diagnosis of "incurable cancer" is increasingly able to be changed to a chronic disease that is manageable over long periods, resulting in a change in the clinical management of cancer patients with solid tumors. New parameters are needed to measure the success of targeted therapy in clinical trials.

MATERIALS AND METHODS

Review article on the basis of selective literature research.

RESULTS

In order to assess how well solid tumors respond to treatment, size-based criteria called RECIST (Response Evaluation Criteria in Solid tumors) have been defined. These criteria have been validated in large oncology trials and are currently used most frequently. New molecular therapies often do not - or at least do not immediately - reduce the size of a tumor. Therefore, RECIST evaluation should be critically assessed especially in the case of modern therapies. Any additional available tumor biology information should be considered. In radiology new methods and developments of RECIST have been introduced to better assess the success of targeted therapy.

CONCLUSION

Assessment according to RECIST has been proven for the follow-up of classic tumor therapy. For the monitoring of targeted therapies, new parameters are often required. Therefore, some specific tumor- and therapy-adapted criteria have already been defined to better evaluate treatment success in clinical trials.

Phase II study of first-line trebananib plus sorafenib in patients with advanced hepatocellular carcinoma (HCC)

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Background: Trebananib is a first-in-class antiangiogenic therapy that sequesters Ang1 and Ang 2, preventing their interaction with the Tie 2 receptor. A previous study of the combination of trebananib with sorafenib in renal cell carcinoma showed an acceptable toxicity profile. Elevated Ang 2 levels have been associated with a poor prognosis in HCC. We thus evaluated the safety and efficacy of trebananib plus sorafenib in HCC. Methods: Patients with HCC, ECOG ≤ 2, Childs-Pugh A, and adequate organ function received IV trebananib at 10mg/kg weekly (cohort 1) or 15 mg/kg weekly (cohort 2) plus sorafenib 400 mg PO twice daily. Thirty patients were accrued to each cohort to provide a power of 80% with the 1-sided exact test for single proportion at α = 0.20 to show a ≥ 78% PFS rate at 4 months relative to 62% reported in the sorafenib historical control. Secondary endpoints included safety and tolerability, progression free survival, objective response rate, disease control rate, time to progression, and overall survival. Results: See table. Conclusions: Trebananib at 10 mg/kg and 15 mg/kg plus sorafenib were well tolerated in patients with advanced HCC. When compared with historical controls, study results did not show an improvement in PFS rate at four months. Clinical trial information: NCT00872014. [Table: see text]

Cytosolic and nuclear caspase-8 have opposite impact on survival after liver resection for hepatocellular carcinoma

Background

An imbalance between proliferation and apoptosis is one of the main features of carcinogenesis. TRAIL (TNF-related apoptosis-inducing ligand) induces apoptosis upon binding to the TRAIL death receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2, whereas binding to TRAIL-R3 and TRAIL-R4 might promote cell survival and proliferation. The anti-tumor activity of TRAIL-R1 and TRAIL-R2 agonists is currently investigated in clinical trials. To gain further insight into the regulation of apoptosis in hepatocellular carcinoma (HCC), we investigated the TRAIL pathway and the regulators of apoptosis caspase-8, Bcl-xL and Mcl-1 in patients with HCC regarding patient survival.

Methods

We analyzed 157 hepatocellular carcinoma patients who underwent partial liver resection or orthotopic liver transplantation and healthy control liver tissue using immunohistochemistry on tissue microarrays for the expression of TRAIL-R1 to TRAIL-R4, caspase-8, Bcl-xL and Mcl-1. Immunohistochemical data were evaluated for potential associations with clinico-pathological parameters and survival.

Results

Whereas TRAIL-R1 was downregulated in HCC in comparison to normal liver tissue, TRAIL-R2 and –R4 were upregulated in HCC, especially in G2 and G3 tumors. TRAIL-R1 downregulation and upregulation of TRAIL-R2 and TRAIL-R4 correlated with tumor dedifferentiation (G2/G3). TRAIL-R3, Bcl-xL and Mcl-1 showed no differential expression in tumor tissue compared to normal tissue. The expression levels of TRAIL receptors did not correlate with patient survival after partial hepatectomy. Interestingly, in tumor tissue, but not in normal hepatocytes, caspase-8 showed a strong nuclear staining. Low cytosolic and high nuclear staining intensity of caspase-8 significantly correlated with impaired survival after partial hepatectomy, which, for cytosolic caspase-8, was independent from tumor grade.

Conclusions

Assessment of TRAIL-receptor expression patterns may have therapeutic implications for the use of TRAIL receptor agonists in HCC therapy. Tumor-specific nuclear localisation of caspase-8 in HCC suggests an apoptosis-independent function of caspase-8 and correlates with patient survival.

Sorafenib treatment is save and may affect survival of recurrent hepatocellular carcinoma after liver transplantation

INTRODUCTION

Recurrent hepatocellular carcinoma (HCC) after liver transplantation (LT) is a rare but challenging condition. In most cases, the recurrent tumor is presented with extrahepatic spread. Therefore, systemic treatment with sorafenib has to be assessed. Because of a plethora of possible drug interactions, e.g., with immunosuppressant or anti-infective therapy, safety and feasibility of sorafenib treatment requires special attention.

MATERIALS AND METHODS

We retrospectively analyzed 18 patients who suffered from recurrent advanced HCC after LT between January 2002 and December 2010 at the University Hospital Heidelberg regarding safety of sorafenib treatment and survival.

RESULTS

Results showed that 8 patients were eligible for treatment with sorafenib showing a median time to progression (TTP) of 4.5 months and an overall survival of 9 months. Most common side effects were grades I and II diarrhea and hand-foot syndrome (HFS) which could be managed by sorafenib dose reduction. No grade III or IV adverse events (AEs) were noticed. No patient had to discontinue treatment due to AEs. The ten patients not amenable for sorafenib treatment, due to initial poor performance status or its deterioration after first line treatment, were treated with surgical resection (n = 3), locoregional therapies (n = 1), or palliative radiation therapy (n = 1). They showed a median overall survival of 2.3 months.

CONCLUSION

Sorafenib may represent a therapeutic option for recurrent HCC after LT with manageable side effects. The clinical benefit of sorafenib in this setting is promising but needs to be confirmed in a prospective randomized trial.

Resminostat in advanced hepatocellular carcinoma (HCC): Overall survival subgroup analysis of prognostic factors in the SHELTER trial

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Background: Previously published results of the phase I/II SHELTER study demonstrated efficacy and safety of the novel pan-HDAC inhibitor resminostat in second-line treatment of HCC patients (pts) who had progressed under first-line sorafenib. As patient baseline characteristics might influence treatment outcome, an analysis of their potential influence on overall survival (OS) was performed. Methods: 45 pts with advanced-stage HCC and centrally confirmed radiologic progression under first-line sorafenib were included in a multi-center, two-arm trial. Resminostat was administered either alone or in combination with sorafenib. A Cox proportional-hazards model was used to evaluate the interaction between baseline characteristics and the effect of the two treatment groups on overall survival. Results: In the combination group, pts with Child-Pugh-A, ECOG 0 or absence of vascular invasion had a statistically significant lower risk of death compared to pts with Child-Pugh-B (HR 0.19, 95% CI 0.06-0.55), ECOG 1 (HR 0.15, 95% CI 0.05-0.44), or vascular invasion (HR 0.37, 95% CI 0.15-0.93), respectively. For pts with BCLC-B there was a strong trend, although not statistically significant, of a lower risk of death when compared to pts with BCLC-C (HR 0.43, 95% CI 0.13-1.49). Etiology, prior TACE therapy, extrahepatic spread and interval between first- and second-line treatment had no impact on overall survival in this study. Similar findings were observed in the monotherapy group. Comparing the impact of these baseline characteristics in the combination and monotherapy group, no statistically significant different influence on OS between both treatment groups was observed. Conclusions: Resminostat in combination with sorafenib provides a substantial OS benefit (median OS of 8.1 months) for advanced HCC patients who had developed progressive tumor disease under first-line sorafenib therapy. Subgroup analysis of patient baseline characteristics revealed a significant influence of Child-Pugh index, ECOG classification, and vascular invasion on overall survival, whereas e.g. the interval between first- and second-line treatment had no impact on overall survival. Clinical trial information: NCT00943449.

Analysis of hepatitis C virus resistance to silibinin in vitro and in vivo points to a novel mechanism involving nonstructural protein 4B

Intravenous silibinin (SIL) is an approved therapeutic that has recently been applied to patients with chronic hepatitis C, successfully clearing hepatitis C virus (HCV) infection in some patients even in monotherapy. Previous studies suggested multiple antiviral mechanisms of SIL; however, the dominant mode of action has not been determined. We first analyzed the impact of SIL on replication of subgenomic replicons from different HCV genotypes in vitro and found a strong inhibition of RNA replication for genotype 1a and genotype 1b. In contrast, RNA replication and infection of genotype 2a were minimally affected by SIL. To identify the viral target of SIL we analyzed resistance to SIL in vitro and in vivo. Selection for drug resistance in cell culture identified a mutation in HCV nonstructural protein (NS) 4B conferring partial resistance to SIL. This was corroborated by sequence analyses of HCV from a liver transplant recipient experiencing viral breakthrough under SIL monotherapy. Again, we identified distinct mutations affecting highly conserved amino acid residues within NS4B, which mediated phenotypic SIL resistance also in vitro. Analyses of chimeric viral genomes suggest that SIL might target an interaction between NS4B and NS3/4A. Ultrastructural studies revealed changes in the morphology of viral membrane alterations upon SIL treatment of a susceptible genotype 1b isolate, but not of a resistant NS4B mutant or genotype 2a, indicating that SIL might interfere with the formation of HCV replication sites.

CONCLUSION

Mutations conferring partial resistance to SIL treatment in vivo and in cell culture argue for a mechanism involving NS4B. This novel mode of action renders SIL an attractive candidate for combination therapies with other directly acting antiviral drugs, particularly in difficult-to-treat patient cohorts.

Effects of mycophenolate mofetil introduction in liver transplant patients: results from an observational, non-interventional, multicenter study (LOBSTER)

The benefits of calcineurin inhibitor (CNI)-sparing regimens on renal function following liver transplantation (LT) have been demonstrated in clinical studies. This observational study assessed the real-life effects of mycophenolate mofetil (MMF) introduction in LT patients. Four hundred and ninety-seven patients in whom MMF was introduced according to local standards or clinical considerations were entered. Patients were grouped by time between transplantation and start of MMF (start of study): Group A (n = 263): ≤6 d; Group B (n = 64): >6 d to ≤1 month; Group C (n = 74): >1 month to ≤1 yr; and Group D (n = 96): >1 yr. CNI sparing occurred in all groups, particularly in Groups C and D. Mean MMF doses at 12 months were 1202.7, 1363.5, 1504.7, and 1578.1 mg/d, respectively, in Groups A-D. At introduction of MMF, median glomerular filtration rate was 73.3, 81.7, 62.7, and 53.7 mL/min/1.73 m(2) in Groups A-D. At 12 months, this decreased to 66 mL/min/1.73 m(2) in Groups A and B, remained stable in Group C, and increased in Group D (64.8 mL/min/1.73 m(2) ). Serious adverse drug reactions were lowest in Group D. In conclusion, MMF with a subsequent decrease in CNI was well tolerated and improved renal function even years after transplantation. A more forceful MMF dosing strategy with greater CNI sparing may further improve renal function.

Quantitative therapy response assessment by volumetric iodine-uptake measurement: initial experience in patients with advanced hepatocellular carcinoma treated with sorafenib

OBJECTIVES

To investigate the volumetric iodine-uptake (VIU) changes by dual-energy CT (DECT) in assessing the response to sorafenib treated hepatocellular carcinoma (HCC) patients, compared with AASLD (American Association for the Study of Liver Diseases) and Choi criteria.

MATERIALS AND METHODS

Fifteen patients with HCC receiving sorafenib, monitored with contrast-enhanced DECT scans at baseline and a minimum of one follow-up (8-12 weeks) were retrospectively evaluated. 30 target lesions in total were analyzed for tumor response according to VIU and adapted Choi criteria and compared with the standard AASLD.

RESULTS

According to AASLD criteria, 67% target lesions showed disease control: partial response (PR) in 3% and stable disease (SD) in 63%. 33% lesions progressed (PD). Disease control rate presented by VIU (60%) was similar to AASLD (67%) and Choi (63%) (P>0.05). For disease control group, change in mean VIU was from 149.5 ± 338.3mg to 108.5 ± 284.1mg (decreased 19.1 ± 42.9%); and for progressive disease group, change in mean VIU was from 163.7 ± 346.7 mg to 263.9 ± 537.2 mg (increased 230.5 ± 253.1%). Compared to AASLD (PR, 3%), VIU and Choi presented more PR (33% and 30%, respectively) in disease control group (P<0.05). VIU has moderate consistency with both AASLD (kappa=0.714; P<0.005) and Choi (kappa=0.648; P<0.005), while VIU showed a better consistency and correlation with AASLD (kappa=0.714; P<0.005; r=0.666, P<0.005) than Choi with AASLD (kappa=0.634, P<0.005; r=0.102, P=0.296).

CONCLUSION

VIU measurements by DECT can evaluate the disease control consistent with the current standard AASLD. Measurements are semi-automatic and therefore easy and robust to apply. As VIU reflects vital tumor burden in HCC, it is likely to be an optimal tumor response biomarker in HCC.

Diarrhea is a positive outcome predictor for sorafenib treatment of advanced hepatocellular carcinoma

OBJECTIVE

This study was performed to identify clinical predictors for better survival in patients with advanced hepatocellular carcinoma (HCC) under sorafenib treatment.

METHODS

Between December 2007 and January 2010, 46 patients with advanced HCC were treated with sorafenib until significant tumor progression or intolerable toxicity. We prospectively collected clinical baseline data as well as data on the incidence and severity of toxic side effects of sorafenib to be correlated with progression-free survival and overall survival (OS), respectively.

RESULTS

Only 26.1% (n = 12) of patients tolerated sorafenib without requiring dose reduction. The most frequent grade 3 toxicities were diarrhea (32.6%), hand-foot skin reaction (13.0%), fatigue (4.3%), and nausea/vomiting (2.2%). Eastern Cooperative Oncology Group performance status (p = 0.034) and portal vein infiltration (p = 0.021) significantly correlated with OS. Furthermore, we found a significant correlation between OS and appearance of grade 2 or 3 diarrhea with a median actuarial survival of 11.8 months (95% CI 6.9-16.6) compared to 4.2 months in patients with grade 0 or 1 diarrhea (95% CI 0.0-9.1; p = 0.009). In contrast, appearance of hand-foot skin reaction did neither correlate with progression-free survival nor with OS.

CONCLUSION

Appearance of grade 2 or 3 diarrhea indicates a better OS of HCC patients undergoing sorafenib treatment.

Efficacy, safety, tolerability, and PK of the HDAC inhibitor resminostat in sorafenib-refractory hepatocellular carcinoma (HCC): Phase II SHELTER study

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Background: Resminostat (R), an oral HDAC inhibitor, was studied in the SHELTER trial evaluating safety, PK and efficacy in HCC patients (pts) refractory to sorafenib (S). R was explored as monotherapy and within a novel resensitization approach to overcome tolerance to S by the combination of both drugs. Methods: Pts with advanced HCC (BCLC B/C) were included in a multi-center, two-arm trial. Radiologic progression under S firstline therapy had to be confirmed by central review (RECIST) prior to study entry. A dose escalation of R (range 200 to 600 mg) combined with S (400 or 800 mg) was performed. Arm A investigated the drug combination (R+S), Arm B the monotherapy of R (600 mg). Primary objective was the progression-free survival rate (PFSR) after 12 weeks (w). Secondary objectives included safety, tolerability, tumor response, PFS, TTP, OS and the analyses of PK and biomarkers (BM), incl. AFP, VEGF, HDAC enzyme inhibition, histone acetylation and gene expressions in peripheral blood. Results: 50 pts were enrolled, dose escalation determined 600 mg R and 400 mg S for Arm A. Clinical activity results of 15 evaluable pts from combination treatment revealing a PFSR of 66.6% after 12 w, not all patients in Arm B already reached the 12 w staging. Most frequent AE were CTC grade 1-2 GI complaints (nausea, vomiting) and skin disorders (rash, pruritus, HFSR). Grade 3-4 toxicity (SAE reports) consisted mainly of non-hematological events mostly related to tumor disease. Plasma concentrations of both drugs correlated with administered doses and were in the expected range without obvious influence of preexisting liver disease. BM investigations revealed effective target modulation by R in both arms. Conclusions: The primary study objective was achieved for both treatment arms. R demonstrated a favorable PK, safety and tolerability profile, even in combination with S and despite preexisting liver disease, includig cirrhosis. The observed clinical activity emphazises the resensitizing activity of R by an epigenetic mode-of-action to overcome tolerance to S and warrants further development, in particular for combination therapy in both, first and second line HCC treatment.

Investigation of the HDAC inhibitor resminostat in patients with sorafenib-resistant hepatocellular carcinoma (HCC): Clinical data from the phase I/II SHELTER study

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Background: Resminostat (4SC-201), an oral pan-HDAC inhibitor, is in clinical development in a variety of cancer indications. The SHELTER study aims to evaluate safety, tolerability and efficacy in HCC patients (pts) exhibiting progressive disease under sorafenib first-line therapy.

Methods: Pts with advanced HCC, (BCLC B or C) are included in a multi-center, open-label, two-arm parallel group trial. Radiologic progression under sorafenib is determined acc. to RECIST by central review prior to study entry. For Arm A, dose escalation of resminostat and sorafenib is performed to determine the MTD. Resminostat is administered orally once-daily in a “5+9” schedule, consisting of 5 consecutive treatment days followed by a 9-day rest period resulting in 14 day cycles on dose levels of 200 (DL1), 400 (DL2) and 600 mg (DL3+4), either combined with continuously taken sorafenib at 400 (DL1-3) or 800 mg (DL4) (Arm A), or as resminostat monotherapy (600 mg, Arm B). Primary objective is to determine progression-free survival after 12 weeks (w) (6 cycles). Secondary objectives include safety, tolerability, tumor response, TTP, OS, PK, biomarkers.

Results: To date, 39 pts were treated with 600 mg resminostat alone or on DL1-4 in combination with sorafenib. Up to now, no DLT occurred in 5 pts treated on DL4. Most frequently AE observed include CTC grade 1-2 gastrointestinal complaints such as nausea and vomiting and skin disorders like rash, pruritus and HFSR. CTC Grade 3-4 toxicity documented in SAE reports consisted mainly of no-hematological events and was mostly related to the tumor disease. Interim results revealed that 15 out of 27 pts (56%) assessed after 6 w of treatment, and 11 out of 24 pts after 12 w displayed SD. In one patient treated on DL2, SD persisted for more than 1 year along with good long-term tolerability.

Conclusions: Preliminary clinical data show a favorable drug profile of resminostat either in mono or in combination treatment with sorafenib. No DLT was observed on the highest DL of the combination therapy up to now. Initial data on toxicity and therapeutic activity to overcome resistance to sorafenib are promising and will be updated for the meeting.

Risk factors of survival after liver transplantation for HCC: a multivariate single-center analysis

BACKGROUND

The selection criteria for liver transplantation (LT) in patients with hepatocellular cancer (HCC) are well defined. Increasing evidence suggests that the effectiveness of pre-transplant bridging influences the individual course after LT significantly. Thus, the aim of this study was to determine its impact on tumor progression during waiting time and identify patient subgroups with favorable oncological long-term outcome.

METHODS

Prospectively collected data of 78 consecutive patients undergoing LT for HCC between 2001 and 2007 were analyzed retrospectively. Survival rates were assessed using the Kaplan-Meier estimate. Clinicopathologic prognostic factors were identified by Cox regression analysis.

RESULTS

After 48.9 months of median follow-up, the five-yr overall survival rate is 57% with a five-yr recurrence-free survival rate of 74%. Progressive disease (PD) during bridging was developed in 32% of patients, and a trend toward impaired overall survival in patients with PD before LT was detected in multivariate analysis (p = 0.073). HCC ≥3 cm was associated with a three times increased risk of recurrent disease. Neither fulfillment of MILAN criteria nor bridging with transarterial chemoembolization had an impact on the outcome.

CONCLUSION

PD during waiting time influences the oncological course after LT. However, even with an increasing organ shortage, further studies are warranted to define clear selection criteria based on the biological tumor behavior and allow a more personalized treatment.

Beyond Milan criteria--chances and risks of expanding transplantation criteria for HCC patients with liver cirrhosis

Orthotopic liver transplantation (OLT) is, apart from resection, one important curative treatment for hepatocellular carcinoma (HCC) in liver cirrhosis, and especially attractive because it eliminates both the tumor and the underlying liver disease. The application of restrictive inclusion criteria for OLT in HCC patients resulted in favorable long-term recurrence-free survival. These criteria, however, exclude a subgroup of patients which, despite advanced tumor size, demonstrate an acceptable outcome. As a consequence, expansion of the strict Milan criteria has been discussed. However, this will also deteriorate the average outcome of OLT in HCC patients. Considering that we run short of donor organs, more sophisticated prediction models for survival after OLT for HCC patients are needed to identify patients who benefit best from OLT. Neoadjuvant treatment that is frequently applied as a bridging technique for patients on the waiting list for OLT could provide useful information on tumor behavior to better predict the risk of post-OLT tumor recurrence. This might also allow expansion of the Milan criteria to patients with good response to downstaging methods without negatively affecting post-OLT survival. Furthermore, alternative scoring systems have been suggested to identify HCC patients that might still benefit from resection instead of OLT, and molecular tools are being explored to provide predictive information on HCC biology. This review discusses the advantages and risks of extended inclusion criteria for OLT and the currently available data on alternative prediction models and bridging methods in HCC patients.

Differential expression of the TRAIL/TRAIL-receptor system in patients with inflammatory bowel disease

TNF-related apoptosis inducing-ligand (TRAIL) is a potent inducer of apoptosis and plays an important role in immune regulation. To explore the role of TRAIL in inflammatory bowel disease (IBD), we examined the expression of the TRAIL/TRAIL-receptor system in colonic resections from patients with ulcerative colitis and Crohn's disease in comparison to normal colon and appendicitis. TRAIL and TRAIL-receptor (TRAIL-R) expression was assessed in resections of normal colon, colon of IBD patients, and appendicitis by immunohistochemistry. TRAIL was downregulated in enterocytes of patients with IBD, but was upregulated in mononuclear cells in areas of active mucosal inflammation. For TRAIL-R1, we detected a strong downregulation in the surface epithelium in IBD but not in appendicitis. TRAIL-R2 and TRAIL-R4 were strongly downregulated in the surface epithelium in any kind of mucosal inflammation. TRAIL and TRAIL-R1 are downregulated in enterocytes, and TRAIL is upregulated in mononuclear cells only in IBD but not in normal colon or appendicitis. This may point to a pathophysiologic role of the TRAIL system in inflammatory bowel disease.

Sporadic cases of acute autochthonous hepatitis E virus infection in Southwest Germany

Hepatitis E infection is usually a self-limiting disease and an important cause of acute hepatitis in tropical and subtropical regions where the virus is endemic. In industrialized countries, sporadic cases of acute hepatitis E virus (HEV) infections have been described and the number of documented autochthonous infections seems to be increasing. We report three sporadic cases of autochthonous hepatitis E infections in Southwestern Germany which presented at our university hospital within two years. All cases were men who presented with acute hepatitis, icterus and elevated liver. In case 1 and case 2, liver biopsy revealed acute hepatitis, both patients were positive for anti-HEV antibodies, case 1 was also positive for HEV RNA with a viral load of 3.0 x 10(3)copies/ml in serum. In case 3, anti-HEV antibodies were detectable and HEV RNA was detected in serum (4.3 x 10(3)copies/ml) and stool (1.4 x 10(6)copies/ml). None of the patients had a recent travel history outside Germany and close contact to animals has been denied. HEV sequence analysis of two patients revealed genotype 3 with homologies to other European isolates and isolates from swine. Thus the source of infection remains unclear. Hepatitis E should be considered in differential diagnosis in patients with unexplained hepatitis and patients with acute hepatitis, whatever their age or travel history might be, should be tested for HEV.

Bortezomib sensitizes primary human esthesioneuroblastoma cells to TRAIL-induced apoptosis

TNF-related apoptosis-inducing ligand (TRAIL), a promising novel anti-cancer cytokine of the TNF superfamily, and Bortezomib, the first-in-class clinically used proteasome inhibitor, alone or in combination have been shown to efficiently kill numerous tumor cell lines. However, data concerning primary human tumor cells are very rare. Using primary esthesioneuroblastoma cells we analyzed the anti-tumor potential and the mechanism employed by Bortezomib in combination with TRAIL for the treatment of this rare but aggressive tumor. Expression of components of the TRAIL pathway was analyzed in tumor specimens and isolated primary tumor cells at the protein level. Cells were treated with TRAIL, Bortezomib, and a combination thereof, and apoptosis induction was quantified. Clonogenicity assays were performed to elucidate the long-term effect of this treatment. Despite expressing all components of the TRAIL pathway, freshly isolated primary esthesioneuroblastoma cells were completely resistant to TRAIL-induced apoptosis. They could, however, be very efficiently sensitized by subtoxic doses of Bortezomib. The influence of Bortezomib on the TRAIL pathway was analyzed and showed upregulation of TRAIL death receptor expression, enhancement of the TRAIL death-inducing signaling complex (DISC), and downregulation of anti-apoptotic proteins of the TRAIL pathway. Of clinical relevance, TRAIL-resistant primary tumor cells could be repeatedly sensitized by Bortezomib, providing the basis for repeated clinical application schedules. This is the first report on the highly synergistic induction of apoptosis in primary esthesioneuroblastoma cells by Bortezomib and TRAIL. This combination, therefore, represents a promising novel therapeutic option for esthesioneuroblastoma.

Yes and PI3K bind CD95 to signal invasion of glioblastoma

Invasion of surrounding brain tissue by isolated tumor cells represents one of the main obstacles to a curative therapy of glioblastoma multiforme. Here we unravel a mechanism regulating glioma infiltration. Tumor interaction with the surrounding brain tissue induces CD95 Ligand expression. Binding of CD95 Ligand to CD95 on glioblastoma cells recruits the Src family member Yes and the p85 subunit of phosphatidylinositol 3-kinase to CD95, which signal invasion via the glycogen synthase kinase 3-beta pathway and subsequent expression of matrix metalloproteinases. In a murine syngeneic model of intracranial GBM, neutralization of CD95 activity dramatically reduced the number of invading cells. Our results uncover CD95 as an activator of PI3K and, most importantly, as a crucial trigger of basal invasion of glioblastoma in vivo.

Bortezomib Sensitizes Primary Human Astrocytoma Cells of WHO Grades I to IV for Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand–Induced Apoptosis

Purpose: Malignant gliomas are the most aggressive human brain tumors without any curative treatment. The antitumor effect of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) in gliomas has thus far only been thoroughly established in tumor cell lines. In the present study, we investigated the therapeutic potential of TRAIL in primary human glioma cells.

Experimental Design: We isolated primary tumor cells from 13 astrocytoma and oligoastrocytoma patients of all four WHO grades of malignancy and compared the levels of TRAIL-induced apoptosis induction, long-term tumor cell survival, caspase, and caspase target cleavage.

Results: We established a stable culture model for isolated primary human glioma cells. In contrast to cell lines, isolated primary tumor cells from all investigated glioma patients were highly TRAIL resistant. Regardless of the tumor heterogeneity, cotreatment with the proteasome inhibitor bortezomib efficiently sensitized all primary glioma samples for TRAIL-induced apoptosis and tremendously reduced their clonogenic survival. Due to the pleiotropic effect of bortezomibenhanced TRAIL DISC formation upon TRAIL triggering, down-regulation of cFLIPL and activation of the intrinsic apoptosis pathway seem to cooperatively contribute to the antitumor effect of bortezomib/TRAIL cotreatment.

Conclusion: TRAIL sensitivity of tumor cell lines is not a reliable predictor for the behavior of primary tumor cells. The widespread TRAIL resistance in primary glioma cells described here questions the therapeutic clinical benefit of TRAIL as a monotherapeutic agent. Overcoming TRAIL resistance by bortezomib cotreatment might, however, provide a powerful therapeutic option for glioma patients.

The promise of TRAIL—potential and risks of a novel anticancer therapy

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising new anticancer biotherapeutic. As shown by many preclinical studies, TRAIL efficiently induces apoptosis in numerous tumor cell lines but not in the majority of normal cells. However, an increasing number of publications report on a predominance of TRAIL resistance in primary human tumor cells, which require sensitization for TRAIL-induced apoptosis. Sensitization of cancer cells by treatment with chemotherapeutic drugs and irradiation has been shown to restore TRAIL sensitivity in many TRAIL-resistant tumor cells. Accordingly TRAIL treatment has been successfully used in different in vivo models for the treatment of tumors also in combination with chemotherapeutics without significant toxicity. However, some reports demonstrated toxicity of TRAIL alone or in combination with chemotherapeutic drugs in normal cells. This review summarizes data concerning the apoptosis-inducing pathways and efficacy of TRAIL, alone or in combination with chemotherapeutic drugs, in primary cancer cells compared to the unwanted effects of TRAIL treatment on normal tissue. We discuss the different in vitro tumor cell models and the potential of different recombinant forms of TRAIL or agonistic antibodies to TRAIL death receptors. Most preclinical studies show a high efficiency of a combinatorial TRAIL-based therapy in animal models and in primary human ex vivo tumor cells with a low toxicity in normal cells. Accordingly clinical phase I/II studies have begun and will be developed further with caution.

TRAIL/bortezomib cotreatment is potentially hepatotoxic but induces cancer-specific apoptosis within a therapeutic window

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) represents a novel promising anticancer biotherapeutic. However, TRAIL-resistant tumor cells require combinatorial regimens to sensitize tumor but not normal cells for TRAIL-induced apoptosis. Here, we investigated the mechanism of the synergistic antitumor effect of bortezomib in combination with TRAIL in hepatoma, colon, and pancreatic cancer cells in comparison to the toxicity in primary human hepatocytes (PHH). TRAIL cotreatment at high but clinically relevant concentrations of bortezomib caused toxicity in PHH which potentially limits the clinical applicability of bortezomib/TRAIL cotreatment. However, at low concentrations of bortezomib TRAIL-resistant hepatoma, colon and pancreatic cancer cell lines but not PHH were efficiently sensitized for TRAIL-induced apoptosis. RNA interference and TRAIL receptor blockage experiments revealed that in bortezomib-treated hepatoma cells TRAIL-R1/TRAIL-R2 up-regulation, enhanced TRAIL DISC formation and cFLIPL down-regulation in addition to accumulation of Bak cooperatively sensitized for TRAIL. Bim, although accumulated upon bortezomib treatment, did not play a causal role for TRAIL sensitization in Hep3b cells. Combined treatment with bortezomib and TRAIL massively reduced the clonogenic capacity of hepatoma cells in vitro. Surviving clones could be resensitized for repeated TRAIL treatment.

CONCLUSION

Bortezomib/TRAIL cotreatment bears the risk of severe hepatotoxicity at high but clinically relevant concentrations of bortezomib. However, within a wide therapeutic window bortezomib sensitized different cancer cells but not PHH for TRAIL-induced apoptosis.

Helicobacter pylori-induced apoptosis in T cells is mediated by the mitochondrial pathway independent of death receptors

BACKGROUND

Chronic infection with Helicobacter pylori is related to the pathogenesis of the noncardia carcinoma of the stomach. In this study we investigated the mechanisms of H. pylori-induced apoptosis in T lymphocytes, which could explain a mechanism of immune evasion facilitating chronic inflammation of the mucosa and gastric carcinogenesis.

MATERIALS AND METHODS

The supernatant of H. pylori culture was used to study the mechanism of apoptosis induction in human leukaemia T cell lines Jurkat and CEM and in primary T cells. The cytotoxin associated gene A (CagA) and vacuolating cytotoxin A (Vac A) positive bacterial strain H. pylori 60190 (CagA(+), VacA(+)) and as a control the less toxic H. pylori strain Tx30a (CagA(-), VacA(-)) were used to produce the supernatant. Cell death was determined by DNA fragmentation and protein expression by Western blot.

RESULTS

H. pylori 60190-induced apoptosis was neither blocked by inhibition of the death ligands TRAIL (TNF-related apoptosis-inducing ligand), CD95L/FasL and TNF-alpha (tumour necrosis factor-a) in wild type Jurkat cells nor in FADD(def) (Fas-associated death domain protein) and caspase-8(def) subclones of the Jurkat cell line. Yet, the pancaspase inhibitor zVAD-fmk could inhibit up to 90% of H. pylori-induced apoptosis. Stable transfection of Jurkat wild type cells with Bcl-x(L and) Bcl-2 resulted in marked reduction of H. pylori-induced apoptosis, showing that the mitochondrial pathway is the key regulator. This is supported by the finding that surviving primary human lymphocytes upregulate Bcl-2 when exposed to H. pylori supernatant.

CONCLUSIONS

H. pylori-induced apoptosis of T cells is mediated by the mitochondrial pathway and could create a local environment that facilitates life-long infection by immune evasion.

Preclinical differentiation between apparently safe and potentially hepatotoxic applications of TRAIL either alone or in combination with chemotherapeutic drugs

PURPOSE

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) exhibits potent antitumor activity on systemic administration in nonhuman primates without deleterious side effects for normal tissue. However, there is a controversy about the potential toxicity of TRAIL on human hepatocytes. The use of different recombinant TRAIL forms only partially explains the contradicting reports on TRAIL sensitivity in primary human hepatocytes (PHH).

EXPERIMENTAL DESIGN

To clarify this issue, we comprehensively tested four different recombinant forms of TRAIL for their apoptosis-inducing capacity on PHH obtained from a total of 55 human livers between day 1 and day 8 of in vitro culture.

RESULTS

One day after single-cell isolation, all but one recombinant form of TRAIL [i.e., an untagged form of TRAIL (TRAIL.0)] induced apoptosis in PHH. Apoptosis induction by TRAIL in these cells could only be fully inhibited by concomitant blockade of TRAIL receptor 1 and TRAIL receptor 2. At day 4 of in vitro culture, when surrogate markers indicated optimal hepatocyte in vitro function, only high doses of cross-linked FLAG-TRAIL killed PHH whereas the other three recombinant TRAIL forms did not. Strikingly, cotreatment of day 4 PHH with cisplatin sensitized for TRAIL-induced apoptosis whereas 5-fluorouracil, etoposide, gemcitabine, irinotecan, or oxaliplatin, which are commonly used in the treatment of gastrointestinal cancers, did not.

CONCLUSION

Our data show that whereas TRAIL alone or together with selected chemotherapeutic drugs seems to be safe, the combination of TRAIL with cisplatin is toxic to PHH.

Proteasome inhibition sensitizes hepatocellular carcinoma cells, but not human hepatocytes, to TRAIL

TRAIL exhibits potent anti-tumor activity on systemic administration in mice. Because of its proven in vivo efficacy, TRAIL may serve as a novel anti-neoplastic drug. However, approximately half of the tumor cell lines tested so far are TRAIL resistant, and potential toxic side effects of certain recombinant forms of TRAIL on human hepatocytes have been described. Pretreatment with the proteasome inhibitor MG132 and PS-341 rendered TRAIL-resistant hepatocellular carcinoma (HCC) cell lines but not primary human hepatocytes sensitive for TRAIL-induced apoptosis. We investigated the different levels of possible MG132-induced interference with resistance to apoptotic signal transduction. Although proteasome inhibition efficiently suppressed nuclear factor-kappaB (NF-kappaB) activity, specific suppression of NF-kappaB by mutIkappaBalpha failed to sensitize TRAIL-resistant cell lines for TRAIL-induced apoptosis. In contrast to the previously reported mechanism of sensitization by 5-fluorouracil (5-FU), cellular FLICE-inhibitory protein (cFLIP)(L) and cFLIP(S) were markedly upregulated in the TRAIL death inducing signaling complex (DISC) by proteasome inhibitor pretreatment. Compared with 5-FU pretreatment, caspase-8 was more efficiently recruited to the DISC in MG132 pretreated cells despite the presence of fewer death receptors and more cFLIP in the DISC. But downregulation of cFLIP by short interference RNA (siRNA) further sensitized the HCC cell lines. In conclusion, these results show that otherwise chemotherapy-resistant tumor cells can be sensitized for TRAIL-induced apoptosis at the DISC level in the presence of high levels of cFLIP, which suggests the existence of an additional factor that modulates the interaction of FADD and the TRAIL death receptors. Of clinical relevance, proteasome inhibitors sensitize HCC cells but not primary human hepatocytes for TRAIL-induced apoptosis.

Transforming growth factor beta can mediate apoptosis via the expression of TRAIL in human hepatoma cells

Transforming growth factor beta (TGF-beta) has been shown to induce apoptotic cell death in normal and transformed hepatocytes. However, the exact mechanism through which TGF-beta induces cell death is still unknown. We examined a potential role of various death receptor/ligand systems in TGF-beta-induced apoptosis and identified the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a mediator of TGF-beta-induced apoptosis in hepatoma cells. TGF-beta-induced apoptosis is significantly impaired upon blockage of TRAIL. We show that TRAIL is upregulated in hepatoma cells upon treatment with TGF-beta, whereas TRAIL receptor levels remain unchanged. In conclusion, our results provide evidence that the TRAIL system is critically involved in TGF-beta-induced cell death in liver pathology.

Enhanced caspase-8 recruitment to and activation at the DISC is critical for sensitisation of human hepatocellular carcinoma cells to TRAIL-induced apoptosis by chemotherapeutic drugs

Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) exhibits potent antitumour activity upon systemic administration in mice without showing the deleterious side effects observed with other apoptosis-inducing members of the TNF family such as TNF and CD95L. TRAIL may, thus, have great potential in the treatment of human cancer. However, about 60% of tumour cell lines are not sensitive to TRAIL. To evaluate the mechanisms of tumour resistance to TRAIL, we investigated hepatocellular carcinoma (HCC) cell lines that exhibit differential sensitivity to TRAIL. Pretreatment with chemotherapeutic drugs, for example, 5-fluorouracil (5-FU), rendered the TRAIL-resistant HCC cell lines sensitive to TRAIL-induced apoptosis. Analysis of the TRAIL death-inducing signalling complex (DISC) revealed upregulation of TRAIL-R2. Caspase-8 recruitment to and its activation at the DISC were substantially increased after 5-FU sensitisation, while FADD recruitment remained essentially unchanged. 5-FU pretreatment downregulated cellular FLICE-inhibitory protein (cFLIP) and specific cFLIP downregulation by small interfering RNA was sufficient to sensitise TRAIL-resistant HCC cell lines for TRAIL-induced apoptosis. Thus, a potential mechanism for TRAIL sensitisation by 5-FU is the increased effectiveness of caspase-8 recruitment to and activation at the DISC facilitated by the downregulation of cFLIP and the consequent shift in the ratio of caspase-8 to cFLIP at the DISC.