Thieno[3,2-b]pyridine: Attractive scaffold for highly selective inhibitors of underexplored protein kinases with variable binding mode.

Protein kinases are key regulators of numerous biological processes and aberrant kinase activity can cause various diseases, particularly cancer. Herein, we report the identification of new series of highly selective kinase inhibitors based on the thieno[3,2-b]pyridine scaffold. The weak interaction of the thieno[3,2-b]pyridine core with the kinase hinge region allows for profoundly different binding modes all of which maintain high kinome-wide selectivity, as illustrated by the isomers MU1464 and MU1668.

A novel thrombocytopenia-4-causing CYCS gene variant decreases caspase activity: Three-generation study.

The CYCS gene is highly evolutionarily conserved, with only a few pathogenic variants that cause thrombocytopenia-4 (THC4). Here, we report a novel CYCS variant NM_018947.6: c.

CD20 expression regulates CD37 levels in B-cell lymphoma - implications for immunotherapies.

Rituximab (RTX) plus chemotherapy (R-CHOP) applied as a first-line therapy for lymphoma leads to a relapse in approximately 40% of the patients. Therefore, novel approaches to treat aggressive lymphomas are being intensively investigated. Several RTX-resistant (RR) cell lines have been established as surrogate models to study resistance to R-CHOP.

Lyn Phosphorylates and Controls ROR1 Surface Dynamics During Chemotaxis of CLL Cells.

Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) are malignancies characterized by the dependence on B-cell receptor (BCR) signaling and by the high expression of ROR1, the cell surface receptor for Wnt-5a. Both, BCR and ROR1 are therapeutic targets in these diseases and the understanding of their mutual cross talk is thus of direct therapeutic relevance. In this study we analyzed the role of Lyn, a kinase from the Src family participating in BCR signaling, as a mediator of the BCR-ROR1 crosstalk.

A Variant in a Czech Family with Monoallelic Bernard-Soulier Syndrome.

Bernard-Soulier syndrome (BSS) is a rare inherited disorder characterized by unusually large platelets, low platelet count, and prolonged bleeding time. BSS is usually inherited in an autosomal recessive (AR) mode of inheritance due to a deficiency of the GPIb-IX-V complex also known as the von Willebrand factor (VWF) receptor. We investigated a family with macrothrombocytopenia, a mild bleeding tendency, slightly lowered platelet aggregation tests, and suspected autosomal dominant (AD) inheritance.

Hypermethylation of CD19 promoter enables antigen-negative escape to CART-19 in vivo and in vitro.

Background: Anti-CD19 chimeric antigen receptor T cells (CART-19) frequently induce remissions in hemato-oncological patients with recurred and/or refractory B-cell tumors. However, malignant cells sometimes escape the immunotherapeutic targeting by gene mutations, alternative splicing or lineage switch, commonly causing lack of CD19 expression on the surface of neoplastic cells. We assumed that, in addition to the known mechanisms, other means could act on CD19 to drive antigen-negative relapse.

Current State of CAR T-Cell Therapy in Chronic Lymphocytic Leukemia.

Chimeric antigen receptor (CAR) T-cell therapy has already achieved remarkable remissions in some difficult-to-treat patients with B-cell malignancies. Although the clinical experience in chronic lymphocytic leukemia (CLL) patients is limited, the proportion of remissions reached in this disease is clearly the lowest from the spectrum of B-cell tumors. In this review, we discuss the antigenic targets exploited in CLL CAR-T therapy, the determinants of favorable responses, as well as the mechanisms of treatment failure specific to this disease.

Functional analysis of germline mutation causing inherited thrombocytopenia and secondary acute lymphoblastic leukemia or essential thrombocythemia.

Germline mutations in gene cause inherited thrombocytopenia with leukemia predisposition. Here, we report on functional validation of W380R mutation segregating with thrombocytopenia in a family where two family members also suffered from acute lymphoblastic leukemia (ALL) or essential thrombocythemia (ET). analysis predicted impaired DNA binding due to W380R mutation.

Performance of anti-CD19 chimeric antigen receptor T cells in genetically defined classes of chronic lymphocytic leukemia.

Background: While achieving prolonged remissions in other B cell-derived malignancies, chimeric antigen receptor (CAR) T cells still underperform when injected into patients with chronic lymphocytic leukemia (CLL). We studied the influence of genetics on CLL response to anti-CD19 CAR T-cell therapy.

Methods: First, we studied 32 primary CLL samples composed of 26 immunoglobulin heavy-chain gene variable ()-unmutated (9 -mutated, 8 -mutated, and 9 without mutations in , , or ) and 6 -mutated samples without mutations in the above-mentioned genes.

CD20 is dispensable for B-cell receptor signaling but is required for proper actin polymerization, adhesion and migration of malignant B cells.

Surface protein CD20 serves as the critical target of immunotherapy in various B-cell malignancies for decades, however its biological function and regulation remain largely elusive. Better understanding of CD20 function may help to design improved rational therapies to prevent development of resistance. Using CRISPR/Cas9 technique, we have abrogated CD20 expression in five different malignant B-cell lines.

MEK inhibitors block growth of lung tumours with mutations in ataxia-telangiectasia mutated.

Lung cancer is the leading cause of cancer deaths, and effective treatments are urgently needed. Loss-of-function mutations in the DNA damage response kinase ATM are common in lung adenocarcinoma but directly targeting these with drugs remains challenging. Here we report that ATM loss-of-function is synthetic lethal with drugs inhibiting the central growth factor kinases MEK1/2, including the FDA-approved drug trametinib.

Treatment of chronic lymphocytic leukemia with monoclonal antibodies, where are we heading?

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in the western world and monoclonal antibodies (mAbs) are important part of CLL treatment. The goal of this article was to summarize current literature on the position of mAbs in CLL treatment and to mention factors influencing effectiveness of mAbs in CLL. Several new mAbs have been developed and investigated in CLL over the past few years.

A reversible gene trap collection empowers haploid genetics in human cells.

Knockout collections are invaluable tools for studying model organisms such as yeast. However, there are no large-scale knockout collections of human cells. Using gene-trap mutagenesis in near-haploid human cells, we established a platform to generate and isolate individual 'gene-trapped cells' and used it to prepare a collection of human cell lines carrying single gene-trap insertions.

PAG/Cbp suppression reveals a contribution of CTLA-4 to setting the activation threshold in T cells.

Background: PAG/Cbp represents a ubiquitous mechanism for regulating Src family kinases by recruiting Csk to the plasma membrane, thereby controlling cellular activation. Since Src kinases are known oncogenes, we used RNA interference in primary human T cells to test whether the loss of PAG resulted in lymphocyte transformation.

Results: PAG-depletion enhanced Src kinase activity and augmented proximal T-cell receptor signaling; exactly the phenotype expected for loss of this negative regulator.

Functional drug-gene interactions in lung cancer.

Despite the dawn of the genomic information era, the challenges of cancer treatment remain formidable. Particularly for the most prevalent cancer types, including lung cancer, successful treatment of metastatic disease is rare and escalating costs for modern targeted drugs place an increasing strain on healthcare systems. Although powerful diagnostic tools to characterize individual tumor samples in great molecular detail are becoming rapidly available, the transformation of this information into therapy provides a major challenge.

A chemical-genetic screen reveals a mechanism of resistance to PI3K inhibitors in cancer.

Linking the molecular aberrations of cancer to drug responses could guide treatment choice and identify new therapeutic applications. However, there has been no systematic approach for analyzing gene-drug interactions in human cells. Here we establish a multiplexed assay to study the cellular fitness of a panel of engineered isogenic cancer cells in response to a collection of drugs, enabling the systematic analysis of thousands of gene-drug interactions.

Integrating signals from the T-cell receptor and the interleukin-2 receptor.

T cells orchestrate the adaptive immune response, making them targets for immunotherapy. Although immunosuppressive therapies prevent disease progression, they also leave patients susceptible to opportunistic infections. To identify novel drug targets, we established a logical model describing T-cell receptor (TCR) signaling.

Cannabinoid receptor type 1- and 2-mediated increase in cyclic AMP inhibits T cell receptor-triggered signaling.

The aim of this study was to characterize inhibitory mechanisms on T cell receptor signaling mediated by the cannabinoid receptors CB1 and CB2. Both receptors are coupled to G(i/o) proteins, which are associated with inhibition of cyclic AMP formation. In human primary and Jurkat T lymphocytes, activation of CB1 by R(+)-methanandamide, CB2 by JWH015, and both by Delta9-tetrahydrocannabinol induced a short decrease in cyclic AMP lasting less than 1 h.

Mechanisms of opioid-mediated inhibition of human T cell receptor signaling.

Opioids are widely used for the treatment of severe pain. However, it is also known that opioids, in particular morphine, cause immunosuppression. Therefore, their use may complicate treatment of persons with an already impaired immune system, e.

Control of lymphocyte development and activation by negative regulatory transmembrane adapter proteins.

Signals emanating from antigen receptors critically regulate immune cell activation, survival, and differentiation. Transmembrane adapter proteins (TRAPs), a group of molecules that organize signaling complexes at the plasma membrane, play a pivotal role in propagating and fine-tuning antigen receptor-mediated signaling. During the last years, it has been demonstrated that most of the TRAPs possess inhibitory functions, including linker for activation of T cells (LAT), the best characterized adapter that links the T-cell receptor (TCR) to Ca(2+) flux and mitogen-activated protein kinase activation.

A displaced PAG enhances proximal signaling and SDF-1-induced T cell migration.

PAG, the phosphoprotein associated with glycosphingolipid-enriched microdomains (GEM), negatively regulates Src family kinases by recruiting C-terminal Src kinase (Csk) to the membrane, where Csk phosphorylates the inhibitory tyrosine of the Src kinases. S-acylation of a CxxC motif juxtaposed to the transmembrane domain within PAG has been proposed to be responsible for targeting PAG to the lipid rafts. Here, we present the characterization of a mutant PAG molecule lacking the palmitoylation motif.

Fyn regulates the duration of TCR engagement needed for commitment to effector function.

In naive T cells, engagement of the TCR with agonist peptide:MHC molecules leads to phosphorylation of key intracellular signaling intermediates within seconds and this peaks within minutes. However, the cell does not commit to proliferation and IL-2 cytokine production unless receptor contact is sustained for several hours. The biochemical basis for this transition to full activation may underlie how T cells receive survival signals while maintaining tolerance, and is currently not well understood.

A novel negative regulatory function of the phosphoprotein associated with glycosphingolipid-enriched microdomains: blocking Ras activation.

In primary human T cells, anergy induction results in enhanced p59Fyn activity. Because Fyn is the kinase primarily responsible for the phosphorylation of PAG (the phosphoprotein associated with glycosphingolipid-enriched microdomains), which negatively regulates Src-kinase activity by recruiting Csk (the C-terminal Src kinase) to the membrane, we investigated whether anergy induction also affects PAG. Analysis of anergic T cells revealed that PAG is hyperphosphorylated at the Csk binding site, leading to enhanced Csk recruitment and inhibitory tyrosine phosphorylation within Fyn.

Right time, right place: the organization of membrane proximal signaling.

The basic mechanisms of lymphocyte activation are well established, with stimulation via the antigen receptor inducing a rapid wave of tyrosine phosphorylation that requires the coordinated action of multiple protein tyrosine kinase families. This in turn leads to the generation of second messengers like Ca(2+), diacylglycerol (DAG) and inositoltrisphosphate (IP(3)) as well as the activation of effector molecules like Ras and the mitogen-activated protein kinases (MAPKs) and ultimately in activation of the transcription factors NFAT, AP-1, and NF-kappaB, resulting in gene transcription. Researchers, hoping to interconnect these events, have identified a multitude of proteins, among which is a relatively new group, the transmembrane adaptor proteins (TRAPs).