A first-in-class dual-chelator theranostic agent designed for use with imaging-therapy radiometal pairs of different elements.

A covalent adduct of DFOB and DOTA separated by a l-lysine residue (DFOB-l-Lys- -DOTA) exhibited remarkable regioselective metal binding, with {H}-C NMR spectral shifts supporting Zr(iv) coordinating to the DFOB unit, and Lu(iii) coordinating to the DOTA unit. This first-in-class, dual-chelator theranostic design could enable the use of imaging-therapy radiometal pairs of different elements, such as Zr for positron emission tomography (PET) imaging and Lu for low-energy β-particle radiation therapy. DFOB-l-Lys- -DOTA was elaborated with an amine-terminated polyethylene glycol extender unit (PEG4) to give DFOB- -(PEG4)-l-Lys- -DOTA (compound D2) to enable installation of a phenyl-isothiocyanate group (Ph-NCS) for subsequent monoclonal antibody (mAb) conjugation (mAb = HuJ591).

Development of [Ac]Ac-DOTA-C595 as radioimmunotherapy of pancreatic cancer: in vitro evaluation, dosimetric assessment and detector calibration.

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy which may benefit from radioimmunotherapy. Previously, [Lu]Lu-DOTA-C595 has been developed as a beta-emitting radioimmunoconjugate to target cancer-specific mucin 1 epitopes (MUC1-CE) overexpressed on PDAC. However, the therapeutic effect may be enhanced by using an alpha-emitting radionuclide such as Actinium-225 (Ac-225).

In vitro characterisation of [Lu]Lu-DOTA-C595 as a novel radioimmunotherapy for MUC1-CE positive pancreatic cancer.

Background: Pancreatic ductal adenocarcinoma (PDAC) continues to be a malignancy with an unmet clinical demand. Development of radioimmunoconjugates which target cancer-specific receptors provides an opportunity for radioimmunotherapy of both metastatic and primary PDAC. In this study, we characterised the in vitro behaviour of a novel beta-emitting radioimmunoconjugate [Lu]Lu-DOTA-C595 as a therapeutic agent against PDAC.

A digital twin for Cu production with cyclotron and solid target system.

One method for finding reliable and cost-effective solutions for designing radioisotope production systems is represented by the "digital twin" philosophy of design. Looking at cyclotron solid targets, uncertainties of the particle beam, material composition and geometry play a crucial role in determining the results. The difference between what has been designed and what can be effectively manufactured, where processes such as electroplating are poorly controllable and generate large non-uniformities in deposition, must also be considered.

Preliminary Development and Testing of C595 Radioimmunoconjugates for Targeting MUC1 Cancer Epitopes in Pancreatic Ductal Adenocarcinoma.

Mucin 1 is a transmembrane glycoprotein which overexpresses cancer-specific epitopes (MUC1-CE) on pancreatic ductal adenocarcinoma (PDAC) cells. As PDAC is a low survival and highly aggressive malignancy, developing radioimmunoconjugates capable of targeting MUC1-CE could lead to improvements in PDAC outcomes. The aim of this study was to develop and perform preliminary testing of diagnostic and therapeutic radioimmunoconjugates for PDAC using an anti-MUC1 antibody, C595.

Fc gamma receptor is not required for in vivo processing of radio- and drug-conjugates of the dead tumor cell-targeting monoclonal antibody, APOMAB®.

The Fc region of a monoclonal antibody (mAb) can play a crucial role in its biodistribution and therapeutic activity. The chimeric mAb, chDAB4 (APOMAB®), which binds to dead tumor cells after DNA-damaging anticancer treatment, has been studied pre-clinically in both diagnostic and therapeutic applications in cancer. Given that macrophages contribute to the tumor accumulation of chDAB4 and its potency as an antibody drug conjugate in vivo, we next wanted to determine whether the Fc region of the chDAB4 mAb also contributed.

Toll-like receptors change morphine-induced antinociception, tolerance and dependence: Studies using male and female TLR and signalling gene KO mice.

Toll-like receptors (TLR) have been proposed as a site of action that alters opioid pharmacodynamics. However, a comprehensive assessment of acute opioid antinociception, tolerance and withdrawal behaviours in genetic null mutant strains with altered innate immune signalling has not been performed. Nor has the impact of genetic deletion of TLR2/4 on high-affinity opioid receptor binding.

Positron Emission Tomographic Imaging of Tumor Cell Death Using Zirconium-89-Labeled APOMAB® Following Cisplatin Chemotherapy in Lung and Ovarian Cancer Xenograft Models.

Purpose: Early detection of tumor treatment responses represents an unmet clinical need with no approved noninvasive methods. DAB4, or its chimeric derivative, chDAB4 (APOMAB®) is an antibody that targets the Lupus associated antigen (La/SSB). La/SSB is over-expressed in malignancy and selectively targeted by chDAB4 in cancer cells dying from DNA-damaging treatment.

Improved non-invasive positron emission tomographic imaging of chemotherapy-induced tumor cell death using Zirconium-89-labeled APOMAB®.

Purpose: The chimeric monoclonal antibody (mAb) chDAB4 (APOMAB®) targets the Lupus associated (La)/Sjögren Syndrome-B (SSB) antigen, which is over-expressed in tumors but only becomes available for antibody binding in dead tumor cells. Hence, chDAB4 may be used as a novel theranostic tool to distinguish between responders and nonresponders early after chemotherapy. Here, we aimed to ascertain which positron emitter, Zirconium-89 ([Zr]Zr) or Iodine-124 ([I]I), was best suited to label chDAB4 for post-chemotherapy PET imaging of tumor-bearing mice and to determine which of two different bifunctional chelators provided optimal tumor imaging by PET using [Zr]Zr-labeled chDAB4.

Tumour-associated macrophages process drug and radio-conjugates of the dead tumour cell-targeting APOMAB® antibody.

APOMAB (chDAB4) is a dead tumour cell-targeting antibody which has been used preclinically as a diagnostic agent and therapeutically as a radioimmunotherapy and antibody drug conjugate (ADC). However, little is known of the intra-tumour processing of chDAB4 when bound to dead tumour cells. In this study we examine the role of macrophages in the in vitro and in vivo processing of radiolabelled chDAB4 and a chDAB4 ADC.

Advanced Resistance Studies Identify Two Discrete Mechanisms in to Overcome Antibacterial Compounds that Target Biotin Protein Ligase.

Biotin protein ligase (BPL) inhibitors are a novel class of antibacterial that target clinically important methicillin-resistant () In BPL is a bifunctional protein responsible for enzymatic biotinylation of two biotin-dependent enzymes, as well as serving as a transcriptional repressor that controls biotin synthesis and import. In this report, we investigate the mechanisms of action and resistance for a potent anti-BPL, an antibacterial compound, biotinyl-acylsulfamide adenosine (BASA). We show that BASA acts by both inhibiting the enzymatic activity of BPL in vitro as well as functioning as a transcription co-repressor.

Rapid and automated production of [Ga]gallium chloride and [Ga]Ga-DOTA-TATE on a medical cyclotron.

Introduction: The demand for Gallium-68 (Ga) for labelling PET radiopharmaceuticals has increased over the past few years. Ga is obtained through the decayed parent radionuclide Ge using commercial Ge/Ga generators. The principal limitation of commercial Ge/Ga generators is that only a limited and finite quantity of Ga (<1.

Sulfonamide-Based Inhibitors of Biotin Protein Ligase as New Antibiotic Leads.

Here, we report the design, synthesis, and evaluation of a series of inhibitors of BPL (BPL), where the central acyl phosphate of the natural intermediate biotinyl-5'-AMP () is replaced by a sulfonamide isostere. Acylsulfamide () and amino sulfonylurea () showed potent inhibitory activity ( = 0.007 ± 0.

Exploring hydroxamic acid inhibitors of HDAC1 and HDAC2 using small molecule tools and molecular or homology modelling.

Hydroxamic acid compounds 1-10 containing a N-hydroxycinnamamide scaffold and a 4-(benzylamino)methyl cap group that was either unsubstituted (1) or substituted with one (2-4) or two (5-10) methoxy groups in variable positions were prepared as inhibitors of Zn(II)-containing histone deacetylases (HDACs). The 3,4- (9) and 3,5- (10) bis-methoxy-substituted compounds were the least potent against HeLa nuclear extract, HDAC1 and HDAC2. Molecular modelling showed methoxy groups in the 3-, 4- and 5-position, but not the 2-position, had unfavourable steric interactions with the G32-H33-P34 triad on a loop at the surface of the HDAC2 active site cavity.

Analogues of desferrioxamine B (DFOB) with new properties and new functions generated using precursor-directed biosynthesis.

Desferrioxamine B (DFOB) is a siderophore native to Streptomyces pilosus biosynthesised by the DesABCD enzyme cluster as a high affinity Fe(III) chelator. Although DFOB has a long clinical history for the treatment of chronic iron overload, limitations encourage the development of new analogues. This review describes a recent body of work that has used precursor-directed biosynthesis (PDB) to access new DFOB analogues.

Immuno-PET of Innate Immune Markers CD11b and IL-1β Detects Inflammation in Murine Colitis.

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disease of the gastrointestinal tract. The diagnosis and monitoring of IBD are reliant on endoscopy, which is invasive and does not provide information on specific mediators. Symptom flare in IBD is associated with increased activation of innate immune pathways.

Crystal structure of highly glycosylated human leukocyte elastase in complex with an S2' site binding inhibitor.

Glycosylated human leukocyte elastase (HLE) was crystallized and structurally analysed in complex with a 1,3-thiazolidine-2,4-dione derivative that had been identified as an HLE inhibitor in preliminary studies. In contrast to previously described HLE structures with small-molecule inhibitors, in this structure the inhibitor does not bind to the S1 and S2 substrate-recognition sites; rather, this is the first HLE structure with a synthetic inhibitor in which the S2' site is blocked that normally binds the second side chain at the C-terminal side of the scissile peptide bond in a substrate protein. The inhibitor also induces the formation of crystalline HLE dimers that block access to the active sites and that are also predicted to be stable in solution.

The chemical biology and coordination chemistry of putrebactin, avaroferrin, bisucaberin, and alcaligin.

Dihydroxamic acid macrocyclic siderophores comprise four members: putrebactin (putH), avaroferrin (avaH), bisucaberin (bisH), and alcaligin (alcH). This mini-review collates studies of the chemical biology and coordination chemistry of these macrocycles, with an emphasis on putH. These Fe(III)-binding macrocycles are produced by selected bacteria to acquire insoluble Fe(III) from the local environment.

Dimeric and trimeric homo- and heteroleptic hydroxamic acid macrocycles formed using mixed-ligand Fe(III)-based metal-templated synthesis.

Macrocyclic hydroxamic acids coordinate Fe(III) with high affinity as part of siderophore-mediated bacterial iron acquisition. Trimeric hydroxamic acid macrocycles, such as desferrioxamine E (DFOE), are prevalent in nature, with fewer dimeric macrocycles identified, including putrebactin (pbH), avaroferrin (avH), bisucaberin (bsH) and alcaligin (alH). This work used metal-templated synthesis (MTS) to pre-assemble complexes between one equivalent of Fe(III) and two equivalents of 4-((4-aminobutyl)(hydroxy)amino)-4-oxobutanoic acid (BBH) or 4-((5-aminopentyl)(hydroxy)amino)-4-oxobutanoic acid (PBH).

Exploiting the biosynthetic machinery of Streptomyces pilosus to engineer a water-soluble zirconium(iv) chelator.

The water solubility of a natural product-inspired octadentate hydroxamic acid chelator designed to coordinate Zr(iv)-89 has been improved by using a combined microbiological-chemical approach to engineer four ether oxygen atoms into the main-chain region of a methylene-containing analogue. First, an analogue of the trimeric hydroxamic acid desferrioxamine B (DFOB) that contained three main-chain ether oxygen atoms (DFOB-O) was generated from cultures of the native DFOB-producer Streptomyces pilosus supplemented with oxybis(ethanamine) (OBEA), which competed against the native 1,5-diaminopentane (DP) substrate during DFOB assembly. This precursor-directed biosynthesis (PDB) approach generated a suite of DFOB analogues containing one (DFOB-O), two (DFOB-O) or three (DFOB-O) ether oxygen atoms, with the latter produced as the major species.

Octadentate Zirconium(IV)-Loaded Macrocycles with Varied Stoichiometry Assembled From Hydroxamic Acid Monomers using Metal-Templated Synthesis.

The reaction between Zr(IV) and the forward endo-hydroxamic acid monomer 4-[(5-aminopentyl)(hydroxy)amino]-4-oxobutanoic acid (for-PBH) in a 1:4 stoichiometry in the presence of diphenylphosphoryl azide and triethylamine gave the octadentate Zr(IV)-loaded tetrameric hydroxamic acid macrocycle for-[Zr(DFOT)] ([M + H] calc 887.3, obs 887.2).

New Series of BPL Inhibitors To Probe the Ribose-Binding Pocket of Biotin Protein Ligase.

Replacing the labile adenosinyl-substituted phosphoanhydride of biotinyl-5'-AMP with a N1-benzyl substituted 1,2,3-triazole gave a new truncated series of inhibitors of biotin protein ligase (BPL). The benzyl group presents to the ribose-binding pocket of BPL based on docking. Halogenated benzyl derivatives (, , , and ) proved to be the most potent inhibitors of BPL.