Metabolic rewiring is essential for tumor growth and progression to metastatic disease, yet little is known regarding how cancer cells modify their acquired metabolic programs in response to different metastatic microenvironments. We have previously shown that liver-metastatic breast cancer cells adopt an intrinsic metabolic program characterized by increased HIF-1α activity and dependence on glycolysis. Here, we confirm by in vivo stable isotope tracing analysis (SITA) that liver-metastatic breast cancer cells retain a glycolytic profile when grown as mammary tumors or liver metastases.
View Article and Find Full Text PDFThe C-C motif chemokine receptor 8 (CCR8) is a class A G-protein coupled receptor that has emerged as a promising therapeutic target in cancer. Targeting CCR8 with an antibody has appeared to be an attractive therapeutic approach, but the molecular basis for chemokine-mediated activation and antibody-mediated inhibition of CCR8 are not fully elucidated. Here, we obtain an antagonist antibody against human CCR8 and determine structures of CCR8 in complex with either the antibody or the endogenous agonist ligand CCL1.
View Article and Find Full Text PDFThe drug discovery landscape is ever-evolving and constantly demands revolutionary technology advancements in protein expression and production laboratories. We have built a higher-throughput mid-scale semi-automated protein expression and screening platform to accelerate drug discovery research. The workflow described here enables comprehensive expression and purification screening assessment of challenging or difficult-to-express recombinant proteins in a fast and efficient manner by delivering small but sufficient amounts of high-quality proteins.
View Article and Find Full Text PDFEngineered destruction of target proteins by recruitment to the cell's degradation machinery has emerged as a promising strategy in drug discovery. The majority of molecules that facilitate targeted degradation do so via a select number of ubiquitin ligases, restricting this therapeutic approach to tissue types that express the requisite ligase. Here, we describe a new strategy of targeted protein degradation through direct substrate recruitment to the 26S proteasome.
View Article and Find Full Text PDFThe epidermis is a barrier that prevents water loss while keeping harmful substances from penetrating the host. The impermeable cornified layer of the stratum corneum is maintained by balancing continuous turnover driven by epidermal basal cell proliferation, suprabasal cell differentiation, and corneal shedding. The epidermal desquamation process is tightly regulated by balance of the activities of serine proteases of the Kallikrein-related peptidases (KLK) family and their cognate inhibitor lymphoepithelial Kazal type-related inhibitor (LEKTI), which is encoded by the serine peptidase inhibitor Kazal type 5 gene.
View Article and Find Full Text PDFUnlike classical voltage-gated sodium (Na) channels, Na has been characterized as a voltage-insensitive, tetrodotoxin-resistant, sodium (Na)-activated channel involved in regulating Na homeostasis. However, Na remains refractory to functional characterization in traditional heterologous systems. Here, to gain insight into its atypical physiology, we determine structures of the human Na channel in complex with the auxiliary β3-subunit.
View Article and Find Full Text PDFDepolarizing sodium (Na) leak currents carried by the NALCN channel regulate the resting membrane potential of many neurons to modulate respiration, circadian rhythm, locomotion and pain sensitivity. NALCN requires FAM155A, UNC79 and UNC80 to function, but the role of these auxiliary subunits is not understood. NALCN, UNC79 and UNC80 are essential in rodents, and mutations in human NALCN and UNC80 cause severe developmental and neurological disease.
View Article and Find Full Text PDFNanolipoprotein particles (NLPs) have been evaluated as an delivery vehicle for a variety of molecules of therapeutic interest. However, delivery of peptide-like drugs in combination with therapeutic Fabs has not yet been evaluated. In this study, we describe the development and characterization of cystine-knot peptide (CKP)-containing NLPs and Fab-CKP-NLP conjugates.
View Article and Find Full Text PDFDespite the need to monitor the impact of Cancer Immunotherapy (CI)/Immuno-Oncology (IO) therapeutics on neoantigen-specific T-cell responses, very few clinical programs incorporate this aspect of immune monitoring due to the challenges in high-throughput (HTP) generation of Major Histocompatibility Complex Class I (MHCI) tetramers across a wide range of HLA alleles. This limitation was recently addressed through the development of MHCI complexes with peptides containing a nonnatural UV cleavable amino acid (conditional MHCI ligands) that enabled HTP peptide exchange upon UV exposure. Despite this advancement, the number of alleles with known conditional MHCI ligands is limited.
View Article and Find Full Text PDFDespite the development of effective therapies, a substantial proportion of asthmatics continue to have uncontrolled symptoms, airflow limitation, and exacerbations. Transient receptor potential cation channel member A1 (TRPA1) agonists are elevated in human asthmatic airways, and in rodents, TRPA1 is involved in the induction of airway inflammation and hyperreactivity. Here, the discovery and early clinical development of GDC-0334, a highly potent, selective, and orally bioavailable TRPA1 antagonist, is described.
View Article and Find Full Text PDFIn many tissues, stem cell (SC) proliferation is dynamically adjusted to regenerative needs. How SCs adapt their metabolism to meet the demands of proliferation and how changes in such adaptive mechanisms contribute to age-related dysfunction remain poorly understood. Here, we identify mitochondrial Ca uptake as a central coordinator of SC metabolism.
View Article and Find Full Text PDFThe TRPA1 ion channel is activated by electrophilic compounds through the covalent modification of intracellular cysteine residues. How non-covalent agonists activate the channel and whether covalent and non-covalent agonists elicit the same physiological responses are not understood. Here, we report the discovery of a non-covalent agonist, GNE551, and determine a cryo-EM structure of the TRPA1-GNE551 complex, revealing a distinct binding pocket and ligand-interaction mechanism.
View Article and Find Full Text PDFNanolipoprotein particles (NLPs), a lipid bilayer-based nanoparticle platform, have recently been developed for delivery of a variety of molecules of therapeutic interest, but their potential to deliver Fabs with valencies that exceed those of current multivalent formats has not yet been evaluated. Here we describe the development, optimization, and characterization of Fab-NLP conjugates. NLPs were generated with maleimide reactive lipids for conjugation to a Fab with a C-terminal cysteine.
View Article and Find Full Text PDFCluster of differentiation 20 (CD20) is a B cell membrane protein that is targeted by monoclonal antibodies for the treatment of malignancies and autoimmune disorders but whose structure and function are unknown. Rituximab (RTX) has been in clinical use for two decades, but how it activates complement to kill B cells remains poorly understood. We obtained a structure of CD20 in complex with RTX, revealing CD20 as a compact double-barrel dimer bound by two RTX antigen-binding fragments (Fabs), each of which engages a composite epitope and an extensive homotypic Fab:Fab interface.
View Article and Find Full Text PDFThe expression analysis of recombinant proteins is a challenging step in any high-throughput protein production pipeline. Often multiple expression systems and a variety of expression construct designs are considered for the production of a protein of interest. There is a strong need to triage constructs rapidly and systematically.
View Article and Find Full Text PDFOuter membrane proteins (OMPs) in Gram-negative bacteria dictate permeability of metabolites, antibiotics, and toxins. Elucidating the structure-function relationships governing OMPs within native membrane environments remains challenging. We constructed a diverse library of >3000 monoclonal antibodies to assess the roles of extracellular loops (ECLs) in LptD, an essential OMP that inserts lipopolysaccharide into the outer membrane of .
View Article and Find Full Text PDFOuter membrane proteins (OMPs) in Gram-negative bacteria are essential for a number of cellular functions including nutrient transport and drug efflux. Escherichia coli BamA is an essential component of the OMP β-barrel assembly machinery and a potential novel antibacterial target that has been proposed to undergo large (~15 Å) conformational changes. Here, we explored methods to isolate anti-BamA monoclonal antibodies (mAbs) that might alter the function of this OMP and ultimately lead to bacterial growth inhibition.
View Article and Find Full Text PDFThe movement of core-lipopolysaccharide across the inner membrane of Gram-negative bacteria is catalysed by an essential ATP-binding cassette transporter, MsbA. Recent structures of MsbA and related transporters have provided insights into the molecular basis of active lipid transport; however, structural information about their pharmacological modulation remains limited. Here we report the 2.
View Article and Find Full Text PDFTo test the agreement between high-grade PCa at RP and TMA, and the ability of TMA to predict BCR. Validation of concordance between tissue microarray (TMA) and radical prostatectomy (RP) high-grade prostate cancer (PCa) is crucial because latter determines the treated natural history of PCa. We hypothesized that TMA Gleason score is in agreement with RP pathology and capable of accurately predicting biochemical recurrence (BCR).
View Article and Find Full Text PDFThe Bruton's tyrosine kinase (Btk) inhibitor ibrutinib has shown impressive clinical efficacy in a range of B-cell malignancies. However, acquired resistance has emerged, and second generation therapies are now being sought. Ibrutinib is a covalent, irreversible inhibitor that modifies Cys481 in the ATP binding site of Btk and renders the enzyme inactive, thereby blocking B-cell receptor signal transduction.
View Article and Find Full Text PDFJAK1 is a member of the Janus kinase (JAK) family of non-receptor tyrosine kinases that are activated in response to cytokines and interferons. Here, we present two crystal structures of the human JAK1 FERM and SH2 domains bound to peptides derived from the class II cytokine receptors IFN-λ receptor 1 and IL-10 receptor 1 (IFNLR1 and IL10RA). These structures reveal an interaction site in the JAK1 FERM that accommodates the so-called "box1" membrane-proximal receptor peptide motif.
View Article and Find Full Text PDFVoltage-gated sodium (Nav) channels propagate action potentials in excitable cells. Accordingly, Nav channels are therapeutic targets for many cardiovascular and neurological disorders. Selective inhibitors have been challenging to design because the nine mammalian Nav channel isoforms share high sequence identity and remain recalcitrant to high-resolution structural studies.
View Article and Find Full Text PDFIntroduction: Breast cancer cells display preferences for specific metastatic sites including the bone, lung and liver. Metastasis is a complex process that relies, in part, on interactions between disseminated cancer cells and resident/infiltrating stromal cells that constitute the metastatic microenvironment. Distinct immune infiltrates can either impair the metastatic process or conversely, assist in the seeding, colonization and growth of disseminated cancer cells.
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