Targeting cereblon (CRBN) is currently one of the most frequently reported proteolysis‐targeting chimera (PROTAC) approaches, owing to favorable drug‐like properties of CRBN ligands, immunomodulatory ...imide drugs (IMiDs). However, IMiDs are known to be inherently unstable, readily undergoing hydrolysis in body fluids. Here we show that IMiDs and IMiD‐based PROTACs rapidly hydrolyze in commonly utilized cell media, which significantly affects their cell efficacy. We designed novel CRBN binders, phenyl glutarimide (PG) analogues, and showed that they retained affinity for CRBN with high ligand efficiency (LE >0.48) and displayed improved chemical stability. Our efforts led to the discovery of PG PROTAC 4 c (SJ995973), a uniquely potent degrader of bromodomain and extra‐terminal (BET) proteins that inhibited the viability of human acute myeloid leukemia MV4‐11 cells at low picomolar concentrations (IC50=3 pM; BRD4 DC50=0.87 nM). These findings strongly support the utility of PG derivatives in the design of CRBN‐directed PROTACs.
IMiD‐based PROTACs rapidly hydrolyze in commonly utilized cell media, which significantly affects their cell efficacy. We designed novel BET PROTACs based on phenyl glutarimide (PG) and showed that they retained affinity for CRBN and displayed improved chemical stability. To demonstrate the utility of PG‐based PROTACs we developed SJ995973 (4 c), a uniquely potent degrader of BET proteins.
Flavin adenine dinucleotide (FAD)-dependent bacterial oleate hydratases (OhyAs) catalyze the addition of water to isolated fatty acid carbon–carbon double bonds. Staphylococcus aureus uses OhyA to ...counteract the host innate immune response by inactivating antimicrobial unsaturated fatty acids. Mechanistic information explaining how OhyAs catalyze regiospecific and stereospecific hydration is required to understand their biological functions and the potential for engineering new products. In this study, we deduced the catalytic mechanism of OhyA from multiple structures of S. aureus OhyA in binary and ternary complexes with combinations of ligands along with biochemical analyses of relevant mutants. The substrate-free state shows Arg81 is the gatekeeper that controls fatty acid entrance to the active site. FAD binding engages the catalytic loop to simultaneously rotate Glu82 into its active conformation and Arg81 out of the hydrophobic substrate tunnel, allowing the fatty acid to rotate into the active site. FAD binding also dehydrates the active site, leaving a single water molecule connected to Glu82. This active site water is a hydronium ion based on the analysis of its hydrogen bond network in the OhyA•PEG400•FAD complex. We conclude that OhyA accelerates acid-catalyzed alkene hydration by positioning the fatty acid double bond to attack the active site hydronium ion, followed by the addition of water to the transient carbocation intermediate. Structural transitions within S. aureus OhyA channel oleate to the active site, curl oleate around the substrate water, and stabilize the hydroxylated product to inactivate antimicrobial fatty acids.
Isotopically labeled amino acids are widely used to study the structure and dynamics of proteins by NMR. Herein we describe a facile, gram-scale synthesis of compounds
and
under standard laboratory ...conditions from the common intermediate
.
is obtained via simple deprotection, while
is accessed through a reductive deoxygenation/deuteration sequence and deprotection.
and
provide improved signal intensity using lower amounts of labeled precursor and are alternatives to existing labeling approaches.
3D printing is among the most exciting and rapidly advancing fields of research in materials engineering and device fabrication. The capability of developing a bottom-up approach to device ...fabrication, which eliminates wasted material and the need for complex environmental conditions, is of incredible interest to researchers. The most critical factor in the success of this technology is the development of suitable materials and inks which facilitate the fabrication of the designed functional geometry. Printing of materials on the macroscale and microscale is ultimately simpler and researchers encounter fewer problems in achieving their intended goals. As the printing technologies lead to the micron and submicron scales, the requirements for printing invariably become increasingly stringent and more difficult to overcome. In the past decade or so researchers have tried to develop suitable inks for the development of nanoscale printing of functional electronic materials, with some or little success. Current 3D deposition approaches are leading to successful nanoscale printing of micron/submicron scale functional and multifunctional materials and devices. In this context, this article provides an overview of currently utilized deposition techniques, along with presentations and analyses of successfully formulated and deposited conductive, dielectric, and magnetic inks by researchers in the field.
The temperature dependence of the dielectric properties, along with the field and frequency dependences of the magnetoelectric properties of a CoFe
2
O
4
/Pb(Zr
x
Ti
1-x
)O
3
/CoFe
2
O
4
laminate ...structure has been investigated. The longitudinal magnetoelectric experiments were performed using an AC magnetic field of 3 Oe, with DC magnetic field biases from 0 to 1000 Oe and frequencies of 100 to 92 kHz. The dielectric measurements were taken from 100 Hz to 1 MHz at three temperature conditions: 295 K, the temperature decreasing at 2°K/min to 150 K, and then increasing the temperature up to 295 K again.
Mutations of genes in tumor cells of Triple Negative subset of Breast Cancer (TNBC) deregulate pathways of signal transduction. The loss of tumor suppressor gene PTEN is the most common first event ...associated with basal-like subtype (Martins, De, Almendro, Gonen, and Park, 2012). Here we report for the first time that the functional upregulation of secreted-MMP7, a transcriptional target of Wnt-β-catenin signature pathway in TNBC is associated to the loss of PTEN. We identified differential expression of mRNAs in several key-components genes, and transcriptional target genes of the Wnt-β-catenin pathway (WP), including beta-catenin, FZD7, DVL1, MMP7, c-MYC, BIRC5, CD44, PPARD, c-MET, and NOTCH1 in FFPE tumors samples from TNBC patients of two independent cohorts. A similar differential upregulation of mRNA/protein for beta-catenin, the functional readout of WP, and for MMP7, a transcriptional target gene of beta-catenin was observed in TNBC cell line models. Genetic or pharmacological attenuation of beta-catenin by SiRNA or WP modulators (XAV939 and sulindac sulfide) and pharmacological mimicking of PTEN following LY294002 treatment downregulated MMP7 levels as well as enzymatic function of the secreted MMP7 in MMP7 positive PTEN-null TNBC cells. Patient data revealed that MMP7 mRNA was high in only a subpopulation of TNBC, and this subpopulation was characterized by a concurrent low expression of PTEN mRNA. In cell lines, a high expression of casein-zymograph-positive MMP7 was distinguished by an absence of functional PTEN. A similar inverse relationship between MMP7 and PTEN mRNA levels was observed in the PAM50 data set (a correlation coefficient of -0.54). The PAM50 subtype and outcome data revealed that the high MMP7 group had low pCR (25%) and High Rd (74%) in clinical stage T3 pathologic response in contrast to the high pCR (40%) and low residual disease (RD) (60%) of the low MMP7 group.
An improved, laser-induced fluorescence-based micro-optical biosensor was designed and fabricated, with cyclic olefin copolymer (COC) optical waveguides, a poly(methyl methacrylate) (PMMA) fluidic ...substrate with an array of microlenses, and a COC coupling prism integrated with the waveguide substrate or cover plate. The double-sided hot embossed fluidic substrate had sampling zone microchannels on the bottom and microlenses on the top. Dissolved COC injected into polydimethylsiloxane (PDMS) lost molds embedded the waveguides in the PMMA cover plate and formed the integrated coupling prism. The embedded COC waveguide was flycut down to <inline-formula> <tex-math notation="LaTeX">50~\mu \text{m} </tex-math></inline-formula>. The cover plate and shallow, 1:20 aspect ratio, microchannels were thermal fusion bonded using a pressure-assisted boiling point control system, without sagging. The large COC prism coupled better to the waveguide. The highest intensity evanescent excitation of the waveguide was obtained near the critical angle. The maximum signal-to-noise ratio (SNR) was 119 and the lowest detection limit was 7.34 <inline-formula> <tex-math notation="LaTeX">\times 10^{\mathbf {-20}} </tex-math></inline-formula> mol at a SNR of 2 for a <inline-formula> <tex-math notation="LaTeX">100~\mu \text{m} </tex-math></inline-formula> wide by <inline-formula> <tex-math notation="LaTeX">50~\mu \text{m} </tex-math></inline-formula> deep waveguide. The microlenses highly focused the fluorescent radiation in the sampling zone. The microfabricated waveguide enables rapid, low-cost detection of fluorescent samples with high SNR, a low detection limit, and high sampling efficiency. 2020-0067
Inhibition of members of the bromodomain and extraterminal (BET) family of proteins has proven a valid strategy for cancer chemotherapy. All BET identified to date contain two bromodomains (BD; BD1 ...and BD2) that are necessary for recognition of acetylated lysine residues in the N-terminal regions of histones. Chemical matter that targets BET (BETi) also interact via these domains. Molecular and cellular data indicate that BD1 and BD2 have different biological roles depending upon their cellular context, with BD2 particularly associated with cancer. We have therefore pursued the development of BD2-selective molecules both as chemical probes and as potential leads for drug development. Here we report the structure-based generation of a novel series of tetrahydroquinoline analogs that exhibit >50-fold selectivity for BD2 versus BD1. This selective targeting resulted in engagement with BD-containing proteins in cells, resulting in modulation of MYC proteins and downstream targets. These compounds were potent cytotoxins toward numerous pediatric cancer cell lines and were minimally toxic to nontumorigenic cells. In addition, unlike the pan BETi (+)-JQ1, these BD2-selective inhibitors demonstrated no rebound expression effects. Finally, we report a pharmacokinetic-optimized, metabolically stable derivative that induced growth delay in a neuroblastoma xenograft model with minimal toxicity. We conclude that BD2-selective agents are valid candidates for antitumor drug design for pediatric malignancies driven by the MYC oncogene. SIGNIFICANCE: This study presents bromodomain-selective BET inhibitors that act as antitumor agents and demonstrates that these molecules have
activity towards neuroblastoma, with essentially no toxicity.
•Chv chimeritopes contain 18 linear epitopes from different OspC variants.•Epitope ordering in OspC chimeritopes influences antibody responses.•Inter-epitope linkers were not required for optimal ...antibody responses.•Chv chimeritopes elicit broadly cross-reactive antibody.•Immunization induced antibody has potent bactericidal activity.
Experimental Outer surface protein (Osp) C based subunit chimeritope vaccinogens for Lyme disease (LD) were assessed for immunogenicity, structure, ability to elicit antibody (Ab) responses to divergent OspC proteins, and bactericidal activity. Chimeritopes are chimeric epitope based proteins that consist of linear epitopes derived from multiple proteins or multiple variants of a protein. An inherent advantage to chimeritope vaccinogens is that they can be constructed to trigger broadly protective Ab responses. Three OspC chimeritope proteins were comparatively assessed: Chv1, Chv2 and Chv3. The Chv proteins possess the same set of 18 linear epitopes derived from 9 OspC type proteins but differ in the physical ordering of epitopes or by the presence or absence of linkers. All Chv proteins were immunogenic in mice and rats eliciting high titer Ab. Immunoblot and enzyme linked immunosorbent assays demonstrated that the Chv proteins elicit IgG that recognizes a diverse array of OspC type proteins. The panel included OspC proteins produced by N. American and European strains of the LD spirochetes. Rat anti-Chv antisera uniformly labeled intact, non-permeabilized Borreliella burgdorferi demonstrating that vaccinal Ab can bind to targets that are naturally presented on the spirochete cell surface. Vaccinal Ab also displayed potent complement dependent-Ab mediated killing activity. This study highlights the ability of OspC chimeritopes to serve as vaccinogens that trigger potentially broadly protective Ab responses. In addition to the current use of an OspC chimeritope in a canine LD vaccine, chimeritopes can serve as key components of human LD subunit vaccines.
PDF
