Macrodomains recognize intracellular adenosine diphosphate (ADP)-ribosylation resulting in either removal of the modification or a protein interaction event. Research into compounds that modulate macrodomain functions could make important contributions. We investigated the interactions of all seven individual macrodomains of the human poly(ADP-ribose) polymerase (PARP) family members PARP9, PARP14, and PARP15 with five mono-ADP-ribosylated (automodified) ADP-ribosyltransferase domains using an AlphaScreen assay.
View Article and Find Full Text PDFSelective inhibitors could help unveil the mechanisms by which inhibition of poly(ADP-ribose) polymerases (PARPs) elicits clinical benefits in cancer therapy. We profiled 10 clinical PARP inhibitors and commonly used research tools for their inhibition of multiple PARP enzymes. We also determined crystal structures of these compounds bound to PARP1 or PARP2.
View Article and Find Full Text PDFChem Biol Drug Des
March 2016
PARP-family ADP-ribosyltransferases (PARPs) and sirtuin deacetylases all use NAD(+) as cosubstrate for ADP-ribosyl transfer. PARP inhibitors are important research tools and several are being evaluated in cancer treatment. With the exception of a few tankyrase inhibitors, all current PARP inhibitors mimic the nicotinamide moiety in NAD(+) and block the nicotinamide binding pocket.
View Article and Find Full Text PDFWe describe the synthesis and screening of a DNA-encoded chemical library containing 76230 compounds. In this library, sets of amines and carboxylic acids are directly linked producing encoded compounds with compact structures and drug-like properties. Affinity screening of this library yielded inhibitors of the potential pharmaceutical target tankyrase 1, a poly(ADP-ribose) polymerase.
View Article and Find Full Text PDFProtein ADP-ribosylation is a post-translational modification involved in DNA repair, protein degradation, transcription regulation, and epigenetic events. Intracellular ADP-ribosylation is catalyzed predominantly by ADP-ribosyltransferases with diphtheria toxin homology (ARTDs). The most prominent member of the ARTD family, poly(ADP-ribose) polymerase-1 (ARTD1/PARP1) has been a target for cancer drug development for decades.
View Article and Find Full Text PDFMethods for the rapid and inexpensive discovery of hit compounds are essential for pharmaceutical research and DNA-encoded chemical libraries represent promising tools for this purpose. We here report on the design and synthesis of DAL-100K, a DNA-encoded chemical library containing 103 200 structurally compact compounds. Affinity screening experiments and DNA-sequencing analysis provided ligands with nanomolar affinities to several proteins, including prostate-specific membrane antigen and tankyrase 1.
View Article and Find Full Text PDFThe racemic 3-(4-oxo-3,4-dihydroquinazolin-2-yl)-N-[1-(pyridin-2-yl)ethyl]propanamide, 1, has previously been identified as a potent but unselective inhibitor of diphtheria toxin-like ADP-ribosyltransferase 3 (ARTD3). Herein we describe synthesis and evaluation of 55 compounds in this class. It was found that the stereochemistry is of great importance for both selectivity and potency and that substituents on the phenyl ring resulted in poor solubility.
View Article and Find Full Text PDFInhibiting ADP-ribosyl transferases with PARP-inhibitors is considered a promising strategy for the treatment of many cancers and ischemia, but most of the cellular targets are poorly characterized. Here, we describe an inhibitor of ADP-ribosyltransferase-3/poly(ADP-ribose) polymerase-3 (ARTD3), a regulator of DNA repair and mitotic progression. In vitro profiling against 12 members of the enzyme family suggests selectivity for ARTD3, and crystal structures illustrate the molecular basis for inhibitor selectivity.
View Article and Find Full Text PDFInhibition of ADP-ribosyltransferases with diphtheria toxin homology (ARTD), widely known as the poly(ADP-ribose) polymerase (PARP) family, is a strategy under development for treatment of various conditions, including cancers and ischemia. Here, we give a brief summary of ARTD enzyme functions and the implications for their potential as therapeutic targets. We present an overview of the PARP inhibitors that have been used in clinical trials.
View Article and Find Full Text PDFThe diphtheria toxin-like ADP-ribosyltransferases (ARTDs) are an enzyme family that catalyzes the transfer of ADP-ribose units onto substrate proteins by using nicotinamide adenine dinucleotide (NAD(+)) as a cosubstrate. They have a documented role in chromatin remodelling and DNA repair, and inhibitors of ARTD1 and 2 (PARP1 and 2) are currently in clinical trials for the treatment of cancer. The detailed function of most other ARTDs is still unknown.
View Article and Find Full Text PDFPurpose: Affibody molecules are a novel class of tumour-targeting proteins, which combine small size (7 kDa) and picomolar affinities. The Affibody molecule Z(HER2:342) has been suggested for imaging of HER2 expression in order to select patients for trastuzumab therapy. When optimizing chelators for (99m)Tc-labelling, we have found that synthetic Z(HER2:342) conjugated with mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) and mercaptoacetyl-glycyl-seryl-glycyl (maGSG) chelators provides relatively low renal uptake of radioactivity and could be suitable for therapy.
View Article and Find Full Text PDFAffibody molecules represent a novel class of affinity proteins with a high potential as tracers for radionuclide molecular imaging. In this comparative structure-property study, a series of Affibody molecules with the (99m)Tc-chelators maGGG, maSSS, or maESE attached to the epsilon-amine of the internally positioned K49 was prepared by peptide synthesis, for comparison to molecules with similar chelators positioned at the N-terminus. The conjugates were labeled with (99m)Tc and evaluated in vitro and in vivo.
View Article and Find Full Text PDFThe human epidermal growth factor receptor HER2 has emerged as an important target for molecular imaging of breast cancer. This article presents the design and synthesis of a HER2-targeting affibody molecule with improved stability and tumor targeting capacity, and with potential use as an imaging agent. The 58 aa three-helix bundle protein was assembled using solid-phase peptide synthesis, and a chemoselective ligation strategy was used to establish an intramolecular thioether bond between the side chain thiol group of a cysteine residue, positioned in the loop between helices I and II, and a chloroacetyl group on the side chain amino group of the C-terminal lysine residue.
View Article and Find Full Text PDFThe effects of polar (mercaptoacetyl-triseryl) and negatively charged (mercaptoacetyl-triglumatyl) chelators on the biodistribution of 99mTc-labeled anti-HER2 Affibody molecules were previously investigated. With glycine, serine, and glutamate, we demonstrated that substitution with a single amino acid in the chelator can significantly influence the biodistribution properties and the excretion pathways. Here, we have taken this investigation further, by analyzing the effects of introduction of a positive amino acid residue on the in vivo properties of the 99mTc-labeled Affibody molecule.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
December 2008
Purpose: Affibody molecules are low molecular weight proteins (7 kDa), which can be selected to bind to tumour-associated target proteins with subnanomolar affinity. Because of rapid tumour localisation and clearance from nonspecific compartments, Affibody molecules are promising tracers for molecular imaging. Earlier, (99m)Tc-labelled Affibody molecules demonstrated specific targeting of tumour xenografts.
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