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Searching for new strategies to trigger apoptosis in rhabdomyosarcoma (RMS), we investigated the effect of two novel classes of apoptosis-targeting agents, i.e. monoclonal antibodies against TNF-related apoptosis-inducing ligand (TRAIL) receptor 1 (mapatumumab) and TRAIL receptor 2 (lexatumumab) and small-molecule inhibitors of inhibitor of apoptosis (IAP) proteins. Here, we report that IAP inhibitors synergized with lexatumumab, but not with mapatumumab, to reduce cell viability and to induce apoptosis in several RMS cell lines in a highly synergistic manner (combination index <0.1). Cotreatment-induced apoptosis was accompanied by enhanced activation of caspase-8, -9, and -3; loss of mitochondrial membrane potential; and caspase-dependent apoptosis. In addition, IAP inhibitor and lexatumumab cooperated to stimulate the assembly of a cytosolic complex containing RIP1, FADD, and caspase-8. Importantly, knockdown of RIP1 by RNA interference prevented the formation of the RIP1·FADD·caspase-8 complex and inhibited subsequent activation of caspase-8, -9, and -3; loss of mitochondrial membrane potential; and apoptosis upon treatment with IAP inhibitor and lexatumumab. In addition, RIP1 silencing rescued clonogenic survival of cells treated with the combination of lexatumumab and IAP inhibitor, thus underscoring the critical role of RIP1 in cotreatment-induced apoptosis. By comparison, the TNFα-blocking antibody Enbrel had no effect on IAP inhibitor/lexatumumab-induced apoptosis, indicating that an autocrine TNFα loop is dispensable. By demonstrating that IAP inhibitors and lexatumumab synergistically trigger apoptosis in a RIP1-dependent but TNFα-independent manner in RMS cells, our findings substantially advance our understanding of IAP inhibitor-mediated regulation of TRAIL-induced cell death.
A simple and fast method of lipid analysis of isolated intact mitochondria by means of MALDI-TOF mass spectrometry is described. Mitochondria isolated from bovine heart and yeast have been employed to set up and validate the new method of lipid analysis. The mitochondrial suspension is directly applied over the target and, after drying, covered by a thin layer of the 9-aminoacridine matrix solution. The lipid profiles acquired with this procedure contain all peaks previously obtained by analyzing the lipid extracts of isolated mitochondria by TLC and/or mass spectrometry. The novel procedure allows the quick, simple, precise, and accurate analysis of membrane lipids, utilizing only a tiny amount of isolated organelle; it has also been tested with intact membranes of the bacterium Paracoccus denitrificans for its evolutionary link to present-day mitochondria. The method is of general validity for the lipid analysis of other cell fractions and isolated organelles.
The demand to develop convergent technology platforms, such as bio-functionalized medical devices, is rapidly increasing. However, the loss of biological function of the effector molecules during sterilization represents a significant and general problem. Therefore, we have developed and characterized a nano-coating (NC) formulation capable of maintaining the functionality of proteins on biological-device combination products. As a proof of concept, the NC preserved the structural and functional integrity of an otherwise highly fragile antibody immobilized on polyurethane during deleterious sterilizing irradiation (≥ 25 kGy). The NC procedure enables straight-forward terminal sterilization of bio-functionalized materials while preserving optimal conditioning of the bioactive surface.
Altered metabolism in tumor cells is increasingly recognized as a core component of the neoplastic phenotype. Because p53 has emerged as a master metabolic regulator, we hypothesized that the presence of wild-type p53 in glioblastoma cells could confer a selective advantage to these cells under the adverse conditions of the glioma microenvironment. Here, we report on the effects of the p53-dependent effector Tp53-induced glycolysis and apoptosis regulator (TIGAR) on hypoxia-induced cell death. We demonstrate that TIGAR is overexpressed in glioblastomas and that ectopic expression of TIGAR reduces cell death induced by glucose and oxygen restriction. Metabolic analyses revealed that TIGAR inhibits glycolysis and promotes respiration. Further, generation of reactive oxygen species (ROS) levels was reduced whereas levels of reduced glutathione were elevated in TIGAR-expressing cells. Finally, inhibiting the transketolase isoenzyme transketolase-like 1 (TKTL1) by siRNA reversed theses effects of TIGAR. These findings suggest that glioma cells benefit from TIGAR expression by (i) improving energy yield from glucose via increased respiration and (ii) enhancing defense mechanisms against ROS. Targeting metabolic regulators such as TIGAR may therefore be a valuable strategy to enhance glioma cell sensitivity toward spontaneously occurring or therapy-induced starvation conditions or ROS-inducing therapeutic approaches.
Introduction. Balapiravir (R1626, RG1626) is the prodrug of a nucleoside analogue inhibitor of the hepatitis C virus (HCV) RNA-dependent RNA polymerase (R1479, RG1479). This phase 2, double-blind international trial evaluated the optimal treatment regimen of balapiravir plus peginterferon alfa-2a (40KD)/ribavirin.
Material and methods. Treatment-naive genotype 1 patients (N = 516) were randomized to one of seven treatment groups in which they received balapiravir 500, 1,000, or 1,500 mg twice daily, peginterferon alfa2a (40KD) 180 or 90 Mg/week and ribavirin 1,000/1,200 mg/day or peginterferon alfa-2a (40KD)/ribavirin. The planned treatment duration with balapiravir was reduced from 24 to 12 weeks due to safety concerns.
Results. The percentage of patients with undetectable HCV RNA was consistently higher in all balapiravir groups from week 2 to 12. However, high rates of dose modifications and discontinuations of one/all study drugs compromised the efficacy assessment and resulted in similar sustained virological response rates in the balapiravir groups (range 32-50%) and the peginterferon alfa-2a (40KD)/ribavirin group (43%). Balapiravir was discontinued for safety reasons in 28-36% of patients (most often for lymphopenia) and the percentage of patients with serious adverse events (especially hematological, infection, ocular events) was dose related. Serious hematological adverse events (particularly neutropenia, lymphopenia) were more common in balapiravir recipients. Two deaths in the balapiravir/peginterferon alfa-2a/ribavirin combination groups were considered possibly related to study medication.
Conclusion. Further development of balapiravir for the treatment of chronic hepatitis C has been halted because of the unacceptable benefit to risk ratio revealed in this study (www.ClinicalTrials.gov NCT 00517439).
Introduction: We report on successful endovascular treatment of a hydrofluoric acid burn to the hand.
Report: A worker complained of severe pain in the fingers D II to D V after injury with 60% hydrofluoric acid. A digital subtraction angiography showed vasospasm of the common palmar digital artery. We selectively applied 20% calcium gluconate intra-arterially.
After treatment all arteries were perfused. Alprostadil, acetylsalicylic acid and clopidogrel were administered in conjunction. Pain symptoms improved and sensory and motor functions were restored.
Discussion: Immediate angiography and intra-arterial application of calcium gluconate are recommended to treat hydrofluoric acid burn to a limb.
Background: The transcription factor T-bet is pivotal for initiation of Th1-related immunoactivation. Identification of novel genes directly regulated by T-bet is crucial.
Results: Genome-wide analysis and subsequent experiments revealed that T-bet up-regulates IL-36γ/IL-1F9 in myeloid cells.
Conclusion: IL-1-related IL-36γ is a direct T-bet target in myeloid cells.
Significance: Observations suggest that IL-36γ , besides IFNγ, contributes to T-bet functions in immunopathology
By concerted action in dendritic (DC) and T cells, T-box expressed in T cells (T-bet, Tbx21) is pivotal for initiation and perpetuation of Th1 immunity. Identification of novel T-bet-regulated genes is crucial for further understanding the biology of this transcription factor. By combining siRNA technology with genome-wide mRNA expression analysis, we sought to identify new T-bet-regulated genes in predendritic KG1 cells activated by IL-18. One gene robustly dependent on T-bet was IL-36γ, a recently described novel IL-1 family member. Promoter analysis revealed a T-bet binding site that, along with a κB site, enables efficient IL-36γ induction. Using knock-out animals, IL-36γ reliance on T-bet was extended to murine DC. IL-36γ expression by human myeloid cells was confirmed using monocyte-derived DC and M1 macrophages. The latter model was employed to substantiate dependence of IL-36γ on endogenous T-bet in human primary cells. Ectopic expression of T-bet likewise mediated IL-36γ production in HaCaT keratinocytes that otherwise lack this transcription factor. Additional experiments furthermore revealed that mature IL-36γ has the capability to establish an inflammatory gene expression profile in human primary keratinocytes that displays enhanced mRNA levels for TNFα, CCL20, S100A7, inducible NOS, and IL-36γ itself. Data presented herein shed further light on involvement of T-bet in innate immunity and suggest that IL-36γ, besides IFNγ, may contribute to functions of this transcription factor in immunopathology.
Ubiquitin-binding modules are constituents of cellular proteins that mediate the effects of ubiquitylation by making transient, non-covalent interactions with ubiquitin molecules. While some ubiquitin-binding modules bind single ubiquitin moieties, others are selective for specific ubiquitin chains of different linkage types and lengths. In recent years, functions of ubiquitin chains that are polymerized through their Lys or N-terminal Met (i.e. linear chains) residues have been linked to a variety of cellular processes. Selectivity of ubiquitin-binding modules for different ubiquitin chain types appears as a key to the distinct regulatory consequences during protein quality control pathways, receptor endocytosis, gene transcription, signaling via the NF-κB pathway, and autophagy.
Recent data have clearly shown that a sustained virologic response can be achieved in different HCV infected patient populations with various interferon-free treatment regimens. Despite the successful implementation of telaprevir- and boceprevir-based triple therapies, all-oral regimens will certainly become a first choice for a number of HCV-infected patients in the very near future, as triple therapy approaches are burdened with significant side-effects and limited success in patients with advanced liver fibrosis and prior null-response to pegylated interferon-α (pegIFN-α)/ribavirin therapy. However, available data from phase I and II clinical trials evaluating interferon-free regimens have not yet revealed a clearly outstanding all-oral combination, and numerous challenges remain to be addressed by intensive ongoing and future research. In particular, thus far evaluated all-oral regimens did not cure a satisfactory percentage of patients with unfavorable baseline characteristics, namely patients infected with HCV genotype 1a, previous null-response to pegIFN-α/ribavirin, or liver cirrhosis. In this review, we summarize available data of interferon-free regimens for the treatment of chronic hepatitis C and assess implications for perspectives and challenges in the further development of all-oral therapies.