[Show abstract][Hide abstract] ABSTRACT: Cancer cells can be specifically driven into apoptosis by activating Death-receptor-4 (DR4; TRAIL-R1) and/or Death-receptor-5 (DR5; TRAIL-R2). Albeit showing promising preclinical efficacy, first generation protein therapeutics addressing this pathway, especially agonistic anti-DR4/DR5-monoclonal antibodies, have not been clinically successful to date. Due to their bivalent binding mode, effective apoptosis induction by agonistic TRAIL-R antibodies is achieved only upon additional events leading to antibody-multimer formation. The binding of these multimers to their target subsequently leads to effective receptor-clustering on cancer cells. The research results presented here report on a new class of TRAIL-receptor agonists overcoming this intrinsic limitation observed for antibodies in general. The main feature of these agonists is a TRAIL-mimic consisting of three TRAIL-protomer subsequences combined in one polypeptide chain, termed single-chain-TRAIL-receptor-binding-domain (scTRAIL-RBD). In the active compounds, two scTRAIL-RBDs with three receptor binding sites each are brought molecularly in close proximity resulting in a fusion protein with a hexavalent binding mode. In the case of APG350 - the prototype of this engineering concept - this is achieved by fusing the Fc-part of a human IgG1-mutein C-terminally to the scTRAIL-RBD-polypeptide, thereby creating six receptor binding sites per drug-molecule. In vitro, APG350 is a potent inducer of apoptosis on human tumor cell-lines and primary tumor cells. In vivo, treatment of mice bearing Colo205-xenograft tumors with APG350 showed a dose dependent anti-tumor efficacy. By dedicated muteins we confirmed, that the observed in vivo-efficacy of the hexavalent scTRAIL-RBD fusion proteins is - in contrast to agonistic antibodies - independent of FcγRs based cross-linking events.
Molecular Cancer Therapeutics 10/2013; 12(12). DOI:10.1158/1535-7163.MCT-13-0323 · 6.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The invention provides novel, substituted 3-arylamino pyridine compounds, Figure US08198457-20120612-C00001, pharmaceutically acceptable salts, solvates and prodrug compounds thereof, wherein W, R1, R2, R9, R10, R11, R12, R13, R14 are as defined in the specification. Such compounds are MEK inhibitors and useful in the treatment of hyperproliferative diseases, such as cancer, restenosis and inflammation. Also disclosed is the use of such compounds in the treatment of hyperproliferative diseases in mammals, especially humans, and pharmaceutical compositions containing such compounds.
[Show abstract][Hide abstract] ABSTRACT: APG101 is a glycosylated fusion protein consisting of the extracellular domain of human CD95 (APO-1/Fas) and the Fc domain of human IgG1. Administration of APG101 blocks the interaction between CD95 and its cognate ligand CD95L, thereby inhibiting various pathways involved in e.g. proliferation, migration, differentiation and apoptosis induction. The safety and tolerability of ascending single doses of intravenously applied APG101 was examined in a randomized, double-blind, placebo-controlled, mono-centre "first in man" dose escalation study in 34 healthy male volunteers. Pharmacokinetics and pharmacodynamics were also assessed. The maximum serum concentration of 460 μg/ml was achieved following 1h infusion of the highest dose of 20 mg/kg. The systemic clearance was low (0.4 to 0.5 ml/hkg). Mean terminal elimination half-life was 12 to 15 days. Two patients suffering from malignant glioma received APG101 intravenously under compassionate use conditions. They received doses ranging from 5mg to 600 mg APG101. No adverse events and no clinical significant changes in laboratory parameters related to APG101 were reported. The presence of anti-drug-antibodies (ADA) was investigated and revealed no detectable levels of ADA. Overall, single ascending doses of APG101 up to 20 mg/kgbody weight (bw) administered as infusion over 1h were considered as safe and well tolerated in healthy volunteers. After the application of multiple doses of 400 mg in two glioma patients, steady state for APG101 seemed to be reached. These results support further clinical evaluation of APG101 at a dose of 400 mg per week in glioblastoma patients.
International immunopharmacology 03/2012; 13(1):93-100. DOI:10.1016/j.intimp.2012.03.004 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Injury to the central nervous system initiates an uncontrolled inflammatory response that results in both tissue repair and destruction. Here, we showed that, in rodents and humans, injury to the spinal cord triggered surface expression of CD95 ligand (CD95L, FasL) on peripheral blood myeloid cells. CD95L stimulation of CD95 on these cells activated phosphoinositide 3-kinase (PI3K) and metalloproteinase-9 (MMP-9) via recruitment and activation of Syk kinase, ultimately leading to increased migration. Exclusive CD95L deletion in myeloid cells greatly decreased the number of neutrophils and macrophages infiltrating the injured spinal cord or the inflamed peritoneum after thioglycollate injection. Importantly, deletion of myeloid CD95L, but not of CD95 on neural cells, led to functional recovery of spinal injured animals. Our results indicate that CD95L acts on peripheral myeloid cells to induce tissue damage. Thus, neutralization of CD95L should be considered as a means to create a controlled beneficial inflammatory response.
[Show abstract][Hide abstract] ABSTRACT: For a series of beta-homophenylalanine based inhibitors of dipeptidyl peptidase IV ADME properties were improved by the incorporation of amide replacements. These efforts led to a novel series of potent and selective inhibitors of DPP-4 that exhibit an attractive pharmacokinetic profile and show excellent efficacy in an animal model of diabetes.
[Show abstract][Hide abstract] ABSTRACT: A series of highly potent and selective inhibitors of DPP-4 was optimized for ADMET properties. The effort resulted in the discovery of inhibitor 1g, that exhibits excellent efficacy in an oral glucose tolerance test and an attractive pharmacokinetic profile.
[Show abstract][Hide abstract] ABSTRACT: Adult neurogenesis persists in the subventricular zone and the dentate gyrus and can be induced upon central nervous system injury. However, the final contribution of newborn neurons to neuronal networks is limited. Here we show that in neural stem cells, stimulation of the "death receptor" CD95 does not trigger apoptosis but unexpectedly leads to increased stem cell survival and neuronal specification. These effects are mediated via activation of the Src/PI3K/AKT/mTOR signaling pathway, ultimately leading to a global increase in protein translation. Induction of neurogenesis by CD95 was further confirmed in the ischemic CA1 region, in the naive dentate gyrus, and after forced expression of CD95L in the adult subventricular zone. Lack of hippocampal CD95 resulted in a reduction in neurogenesis and working memory deficits. Following global ischemia, CD95-mediated brain repair rescued behavioral impairment. Thus, we identify the CD95/CD95L system as an instructive signal for ongoing and injury-induced neurogenesis.
[Show abstract][Hide abstract] ABSTRACT: Modifications of DPP-4 inhibitor 5, that was discovered by structure based design, are described and structure-activity relationships discussed. With analogue 7k one of the most potent non-covalent inhibitors of DPP-4 reported to date (IC(50)=0.38nM) was discovered. X-ray structure of inhibitor 7k bound to DPP-4 revealed a hydrogen bonding interaction with Q553. First successful efforts in balancing overall properties, as demonstrated by improved metabolic stability, highlight the potential of this series.
[Show abstract][Hide abstract] ABSTRACT: 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.
Cancer cell 04/2008; 13(3):235-48. DOI:10.1016/j.ccr.2008.02.003 · 23.89 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The co-crystal structure of beta-phenethylamine fragment inhibitor 5 bound to DPP-IV revealed that the phenyl ring occupied the proline pocket of the enzyme. This finding provided the basis for a general hypothesis of a reverse binding mode for beta-phenethylamine-based DPP-IV inhibitors. Novel inhibitor design concepts that obviate substrate-like structure-activity relationships (SAR) were thereby enabled, and novel, potent inhibitors were discovered.
[Show abstract][Hide abstract] ABSTRACT: Dipeptidyl peptidase IV is a clinically validated target for type-2 diabetes and belongs to a family of peptidases with a quite unique post-proline cleavage specificity. Known inhibitors contain a limited number of molecular anchors occupying the small prototypical S1 pocket. A virtual screening approach for such S1-binding fragments was carried out using FlexX docking to evaluate its potential to confirm known and find novel compounds. Several low molecular weight inhibitors exhibiting activities in the micromolar range could be identified as starting points for structure-based design.