SHP2 is a nonreceptor protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell growth and differentiation via the MAPK signaling pathway. SHP2 also plays an important role in ...the programed cell death pathway (PD-1/PD-L1). As an oncoprotein as well as a potential immunomodulator, controlling SHP2 activity is of high therapeutic interest. As part of our comprehensive program targeting SHP2, we identified multiple allosteric binding modes of inhibition and optimized numerous chemical scaffolds in parallel. In this drug annotation report, we detail the identification and optimization of the pyrazine class of allosteric SHP2 inhibitors. Structure and property based drug design enabled the identification of protein–ligand interactions, potent cellular inhibition, control of physicochemical, pharmaceutical and selectivity properties, and potent in vivo antitumor activity. These studies culminated in the discovery of TNO155, (3S,4S)-8-(6-amino-5-((2-amino-3-chloropyridin-4-yl)thio)pyrazin-2-yl)-3-methyl-2-oxa-8-azaspiro4.5decan-4-amine (1), a highly potent, selective, orally efficacious, and first-in-class SHP2 inhibitor currently in clinical trials for cancer.
ABL1 tyrosine-kinase inhibitors (TKI) are front-line therapy for chronic myelogenous leukaemia and are among the best-known examples of targeted cancer therapeutics. However, the dynamic uptake into ...cells of TKIs of low molecular weight and their intracellular behaviour is unknown because of the difficulty of observing non-fluorescent small molecules at subcellular resolution. Here we report the direct label-free visualization and quantification of two TKI drugs (imatinib and nilotinib) inside living cells using hyperspectral stimulated Raman scattering imaging. Concentrations of both drugs were enriched over 1,000-fold in lysosomes as a result of their lysosomotropic properties. In addition, low solubility appeared to contribute significantly to the surprisingly large accumulation of nilotinib. We further show that the lysosomal trapping of imatinib was reduced more than tenfold when chloroquine is used simultaneously, which suggests that chloroquine may increase the efficacy of TKIs through lysosome-mediated drug-drug interaction in addition to the commonly proposed autophagy-inhibition mechanism.
Background: Chronic myelogenous leukemia (CML) and a subset of acute lymphoblastic leukemia (ALL) are caused by the t(9;22)(q34;q11.2) chromosome translocation, resulting in fusion of the BCR and ...ABL1 genes on the Philadelphia chromosome to encode constitutively active ABL1 kinase. Despite the dramatic progress made over the past decade with tyrosine kinase inhibitors (TKIs) in the treatment of CML, allogeneic stem cell transplant is considered the only proven curative therapy. To achieve cure or benefit from treatment-free remissions with pharmacologically-based therapies, it is estimated that patients will likely need to achieve a sustained reduction in tumor burden of 4 logs (MR4) or deeper (MR4.5). Currently, only 39% and 18% of patients achieve MR4 by 24 months of treatment with single agent nilotinib or imatinib, respectively. Furthermore, for a subset of CML patients and the majority of Ph+ ALL patients, resistance develops to current TKI’s as a result of emergence of point mutations in the ATP site of the kinase domain. ABL001 is a potent, selective BCR-ABL inhibitor that maintains activity across most mutations, including T315I, with a distinct, allosteric mechanism of action which recently entered Phase I development for the treatment of patients with CML and Ph+ ALL. ABL001 was developed to be dosed in combination with nilotinib to provide greater pharmacological coverage of BCR-ABL disease and prevent the emergence of resistance.
Methods: Based on X-ray crystallography, NMR and molecular modeling, ABL001 is the result of a structure-guided medicinal chemistry program targeting the myristoyl pocket of the ABL1 kinase. In vitro cell based assays were performed using the Ba/F3 isogenic cell system and a panel of over 300 cell lines. KCL-22 cells were used to develop an in vivo xenograft model to assess the efficacy of ABL001 and the PD marker, pSTAT5, was used to monitor the inhibition of BCR-ABL signaling.
Results: In contrast to TKIs that bind to the ATP-site of the ABL1 kinase domain, NMR and X-Ray crystallography studies confirmed that ABL001 binds to a pocket on the BCR-ABL kinase domain that is normally occupied by the myristoylated N-terminus of ABL1. Upon fusion with BCR, this myristoylated N-terminus that serves to autoregulate ABL1 activity is lost. ABL001 functionally mimics the role of the myristoylated N-terminus by occupying its vacant binding site and restores the negative regulation of the kinase activity. Cell proliferation studies demonstrate that ABL001 selectively inhibited the growth of CML and Ph+ ALL cells with potencies ranging from 1-10nM range. In contrast, BCR-ABL-negative cell lines remained unaffected at concentrations 1000-fold higher. With resistance emerging in the clinic to current TKI’s as a result of point mutations in the ATP-site, ABL001 was tested for activity against clinically observed mutations and found to be active in the low nM range. In the KCL-22 mouse xenograft model, ABL001 displayed potent anti-tumor activity with complete tumor regression observed and a clear dose-dependent correlation with pSTAT5 inhibition. The KCL-22 xenograft model was also used to compare the dosing of ABL001 and nilotinib as single agents to dosing a combination of ABL001 and nilotinib. Single agent dosing regimens led to tumor regressions; however, despite continuous dosing, all tumors relapsed within 30-60 days with evidence of point mutations in the resistant tumors. In contrast, animals treated with the combination of ABL001 and nilotinib achieved sustained tumor regression with no evidence of disease relapse either during the 70 days of treatment or for > 150 days after treatment stopped.
Conclusion: ABL001 selectively inhibited the proliferation of cells expressing the BCR-ABL fusion gene and was active against clinically important mutations that arise with current TKI therapy in CML. In an in vivo model of CML, the combination of ABL001 and nilotinib resulted in complete and sustained tumor regression with no evidence of disease relapse. These results provide proof-of-principle that simultaneous targeting of the myristoyl pocket and ATP-pocket by ABL001 and nilotinib, respectively, promotes a more sustained overall efficacy and prevents the emergence of resistance via acquisition of point mutations in the respective binding sites. ABL001 is currently being evaluated in a Phase 1 study in patients with CML and Ph+ ALL.
Wylie:Novartis Institutes for Biomedical Research, Inc: Employment. Schoepfer:Novartis Institutes for Biomedical Research: Employment. Berellini:Novartis Institutes for Biomedical Research: Employment. Cai:Novartis Institutes for Biomedical Research: Employment. Caravatti:Novartis Institutes for Biomedical Research: Employment. Cotesta:Novartis Institues for Biomedical Research: Employment. Dodd:Novartis Institutes for Biomedical Research: Employment. Donovan:Novartis Institutes for Biomedical Research: Employment. Erb:Novartis Institutes for Biomedical Research: Employment. Furet:Novartis Institutes for Biomedical Research: Employment. Gangal:Novartis Institutes for Biomedical Research: Employment. Grotzfeld:Novartis Institutes for Biomedical Research: Employment. Hassan:Novartis Institutes for Biomedical Research: Employment. Hood:Novartis Institutes for Biomedical Research: Employment. Iyer:Novartis Institutes for Biomedical Research: Employment. Jacob:Novartis Institutes for Biomedical Research: Employment. Jahnke:Novartis Institutes for Biomedical Research: Employment. Lombardo:Novartis Institutes for Biomedical Research: Employment. Loo:Novartis Institutes for Biomedical Research: Employment. Manley:Novartis Institutes for Biomedical Research: Employment. Marzinzik:Novartis Institutes for Biomedical Research: Employment. Palmer:Novartis Institutes for Biomedical Research: Employment. Pelle:Novartis Institutes for Biomedical Research: Employment. Salem:Novartis Institutes for Biomedical Research: Employment. Sharma:Novartis Institutes for Biomedical Research: Employment. Thohan:Novartis Institutes for Biomedical Research: Employment. Zhu:Novartis Institutes for Biomedical Research: Employment. Keen:Novartis Institutes for Biomedical Research: Employment. Petruzzelli:Novartis Institutes for Biomedical Research: Employment. Vanasse:Novartis: Employment, Equity Ownership. Sellers:Novartis: Employment.
Immunoglobulin E （IgE） plays a key role in allergic asthma and is a clinically validated target for monoclonal antibodies. Therapeutic anti-lgE antibodies block the interaction between IgE and the Fc ...epsilon （Fcε） receptor, which eliminates or minimizes the allergic phenotype but does not typically curtail the ongoing production of IgE by B cells. We generated high-affinity anti-lgE antibodies （MEDI4212） that have the potential to both neutralize soluble IgE and eliminate IgE-expressing B-cells through antibody-dependent cell-mediated cytotoxicity. MEDI4212 variants were generated that contain mutations in the Fc region of the antibody or alterations in fucosylation in order to enhance the antibody＇s affinity for FcyRIIla. All MEDI4212 variants bound to human IgE with affinities comparable to the wild-type （WT） antibody. Each variant was shown to inhibit the interaction between IgE and FcεRI, which translated into potent inhibition of FcyRI-mediated function responses. Importantly, all variants bound similarly to IgE at the surface of membrane IgE expressing cells. However, MEDI4212 variants demonstrated enhanced affinity for FcyRIIla including the polymorphic variants at position 158. The improvement in FcyRIIla binding led to increased effector function in cell based assays using both engineered cell lines and class switched human IgE B cells. Through its superior suppression of IgE, we anticipate that effector function enhanced MEDI4212 may be able to neutralize high levels of soluble IgE and provide increased long-term benefit by eliminating the IgE expressing B cells before they differentiate and become IgE secreting plasma cells.
The neural mechanisms that support naturalistic learning via effective pedagogical approaches remain elusive. Here we used functional near-infrared spectroscopy to measure brain activity from ...instructor-learner dyads simultaneously during dynamic conceptual learning. Results revealed that brain-to-brain coupling was correlated with learning outcomes, and, crucially, appeared to be driven by specific scaffolding behaviors on the part of the instructors (e.g., asking guiding questions or providing hints). Brain-to-brain coupling enhancement was absent when instructors used an explanation approach (e.g., providing definitions or clarifications). Finally, we found that machine-learning techniques were more successful when decoding instructional approaches (scaffolding vs. explanation) from brain-to-brain coupling data than when using a single-brain method. These findings suggest that brain-to-brain coupling as a pedagogically relevant measure tracks the naturalistic instructional process during instructor-learner interaction throughout constructive engagement, but not information clarification.
•We investigated instruction-based naturalistic learning using fNIRS hyperscanning.•Instructor-learner brain coupling was driven by specific scaffolding behaviors.•Instructor-learner brain coupling predicted learning outcomes.•Instructor-learner brain coupling was successfully used to decode instructional approaches.
Purpose To investigate relationships between computer-extracted breast magnetic resonance (MR) imaging phenotypes with multigene assays of MammaPrint, Oncotype DX, and PAM50 to assess the role of ...radiomics in evaluating the risk of breast cancer recurrence. Materials and Methods Analysis was conducted on an institutional review board-approved retrospective data set of 84 deidentified, multi-institutional breast MR examinations from the National Cancer Institute Cancer Imaging Archive, along with clinical, histopathologic, and genomic data from The Cancer Genome Atlas. The data set of biopsy-proven invasive breast cancers included 74 (88%) ductal, eight (10%) lobular, and two (2%) mixed cancers. Of these, 73 (87%) were estrogen receptor positive, 67 (80%) were progesterone receptor positive, and 19 (23%) were human epidermal growth factor receptor 2 positive. For each case, computerized radiomics of the MR images yielded computer-extracted tumor phenotypes of size, shape, margin morphology, enhancement texture, and kinetic assessment. Regression and receiver operating characteristic analysis were conducted to assess the predictive ability of the MR radiomics features relative to the multigene assay classifications. Results Multiple linear regression analyses demonstrated significant associations (R
= 0.25-0.32, r = 0.5-0.56, P < .0001) between radiomics signatures and multigene assay recurrence scores. Important radiomics features included tumor size and enhancement texture, which indicated tumor heterogeneity. Use of radiomics in the task of distinguishing between good and poor prognosis yielded area under the receiver operating characteristic curve values of 0.88 (standard error, 0.05), 0.76 (standard error, 0.06), 0.68 (standard error, 0.08), and 0.55 (standard error, 0.09) for MammaPrint, Oncotype DX, PAM50 risk of relapse based on subtype, and PAM50 risk of relapse based on subtype and proliferation, respectively, with all but the latter showing statistical difference from chance. Conclusion Quantitative breast MR imaging radiomics shows promise for image-based phenotyping in assessing the risk of breast cancer recurrence.
RSNA, 2016 Online supplemental material is available for this article.
We investigated afferent inputs from all areas in the frontal cortex (FC) to different subregions in the rostral anterior cingulate cortex (rACC). Using retrograde tracing in macaque monkeys, we ...quantified projection strength by counting retrogradely labeled cells in each FC area. The projection from different FC regions varied across injection sites in strength, following different spatial patterns. Importantly, a site at the rostral end of the cingulate sulcus stood out as having strong inputs from many areas in diverse FC regions. Moreover, it was at the integrative conjunction of three projection trends across sites. This site marks a connectional hub inside the rACC that integrates FC inputs across functional modalities. Tractography with monkey diffusion magnetic resonance imaging (dMRI) located a similar hub region comparable to the tracing result. Applying the same tractography method to human dMRI data, we demonstrated that a similar hub can be located in the human rACC.
Diffuse intrinsic pontine gliomas (DIPGs) are incurable childhood brainstem tumors with frequent histone H3 K27M mutations and recurrent alterations in PDGFRA and TP53. We generated genetically ...engineered inducible mice and showed that H3.3 K27M enhanced neural stem cell self-renewal while preserving regional identity. Neonatal induction of H3.3 K27M cooperated with activating platelet-derived growth factor receptor α (PDGFRα) mutant and Trp53 loss to accelerate development of diffuse brainstem gliomas that recapitulated human DIPG gene expression signatures and showed global changes in H3K27 posttranslational modifications, but relatively restricted gene expression changes. Genes upregulated in H3.3 K27M tumors were enriched for those associated with neural development where H3K27me3 loss released the poised state of apparently bivalent promoters, whereas downregulated genes were enriched for those encoding homeodomain transcription factors.
Display omitted
•H3.3 K27M mutation enhances neural stem cell self-renewal•Neonatal PDGFRα activation and Trp53 loss induces supratentorial and brainstem glioma•H3.3 K27M preferentially accelerates hindbrain tumorigenesis•H3.3 K27M drives bivalent gene activation associated with neurodevelopment in DIPG
Larson et al. show that H3.3 K27M cooperates with active PDGFRα mutant and loss of p53 to induce brainstem gliomas molecularly resembling human DIPG in mice. These tumors show global H3K27 modification but restricted gene expression changes, including upregulation of genes associated with neural development.
Abstract Background The complications of prostate needle biopsy (PNB) are important when considering the benefits and harms of prostate cancer screening. Studies from the United States and Canada ...have recently reported increasing numbers of hospitalizations for infectious complications after PNB. Objective Examine the risk of infectious complications and hospital admissions after PNB in a European screening trial. Design, setting, and participants From 1993 to 2011, 10 474 PNBs were performed in the European Randomized Study of Screening for Prostate Cancer (Rotterdam section). Prophylaxis originally consisted of trimethoprim-sulfamethoxazole. Beginning in 2008, it was changed to ciprofloxacin. Measurements Febrile complications and hospital admissions were assessed by questionnaires 2 wk after PNB. Logistic regression was used to identify risk factors for biopsy-related fever and hospital admission. Results and limitations Fever and hospital admission were reported on 392 of 9241 questionnaires (4.2%) and 78 of 9198 questionnaires (0.8%), respectively. Although most fevers were managed on an outpatient basis, 81% of hospital admissions were for infection. Of the 56 available blood cultures, 34 were positive with Escherichia coli as the predominant organism. On multivariable analysis, prostate enlargement and diabetes were significantly associated with an increased risk of fever after PNB, whereas later year of biopsy was the only factor significantly associated with an increased risk of hospital admission. Conclusions In a European screening trial, <5% PNBs resulted in febrile complications. Significant risk factors included diabetes and prostatic enlargement. Although most fevers were managed on an outpatient basis, infection remained the leading cause of hospital admission after PNB. Consistent with prior international reports, the frequency of hospital admissions after PNB significantly increased over time. Nevertheless, the absolute frequency of hospital admissions related to PNB was low and should not dissuade healthy men who would benefit from early prostate cancer diagnosis from undergoing biopsy when clinically indicated.
Mutations in the
PTEN,
TP53, and
RB1 pathways are obligate events in the pathogenesis of human glioblastomas. We induced various combinations of deletions in these tumor suppressors in astrocytes and ...neural precursors in mature mice, resulting in astrocytomas ranging from grade III to grade IV (glioblastoma). There was selection for mutation of multiple genes within a pathway, shown by somatic amplifications of genes in the PI3K or Rb pathway in tumors in which
Pten or
Rb deletion was an initiating event. Despite multiple mutations within PI3K and Rb pathways, elevated Mapk activation was not consistent. Gene expression profiling revealed striking similarities to subclasses of human diffuse astrocytoma. Astrocytomas were found within and outside of proliferative niches in the adult brain.
► There is selective cooperativity among tumor suppressors for glioma initiation ► Dysregulation at multiple nodes within a pathway is dictated by initiating mutations ► Mouse models recapitulate mutations and expression profiles of human gliomas ► Astrocytomas developed in proliferative and nonproliferative regions of adult brain
PDF
