MYD88 L265P mutations identify a prognostic gene expression signature and a pathway for targeted inhibition in CLL.

The L265P somatic mutation in the Myeloid Differentiation Primary Response 88 (MYD88) gene is a recurrent mutation in chronic lymphocytic leukaemia (CLL). This mutation has functional effects in various haematological malignancies but its role in CLL remains to be fully elucidated. Here, we report that MYD88 L265P mutations are associated with mutated immunoglobulin heavy-chain gene (IGHV-M) status and that among IGHV-M patients, the presence of MYD88 L265P is associated with younger age at diagnosis.

Discovery of a Series of 5,11-Dihydro-6-benzo[]pyrimido[5,4-][1,4]diazepin-6-ones as Selective PI3K-δ/γ Inhibitors.

Dual inhibition of PI3K-δ and PI3K-γ is an established therapeutic strategy for treatment of hematological malignancies. Reported molecules targeting PI3K-δ/γ selectively are chemically similar and based upon isoquinolin-1(2)-one or quinazolin-4(3)-one scaffolds. Here we report a chemically distinct series of potent, selective PI3K-δ/γ inhibitors based on a 5,11-dihydro-6-benzo[]pyrimido[5,4-][1,4]diazepin-6-one scaffold with comparable biochemical potency and cellular effects on PI3K signaling.

Survival of Del17p CLL Depends on Genomic Complexity and Somatic Mutation.

Purpose: Chronic lymphocytic leukemia (CLL) with 17p deletion typically progresses quickly and is refractory to most conventional therapies. However, some del(17p) patients do not progress for years, suggesting that del(17p) is not the only driving event in CLL progression. We hypothesize that other concomitant genetic abnormalities underlie the clinical heterogeneity of del(17p) CLL.

Obatoclax in combination with fludarabine and rituximab is well-tolerated and shows promising clinical activity in relapsed chronic lymphocytic leukemia.

Obatoclax is a small molecule mimetic of the BH3 domain of BCL-2 family proteins. This phase 1 study combining obatoclax with FR was undertaken in chronic lymphocytic leukemia (CLL) patients relapsed after at least one prior therapy. Obatoclax was given as a 3-h infusion on days 1 and 3 and escalated through three dose levels, with standard dose FR days 1-5.

Targeting transcription regulation in cancer with a covalent CDK7 inhibitor.

Tumour oncogenes include transcription factors that co-opt the general transcriptional machinery to sustain the oncogenic state, but direct pharmacological inhibition of transcription factors has so far proven difficult. However, the transcriptional machinery contains various enzymatic cofactors that can be targeted for the development of new therapeutic candidates, including cyclin-dependent kinases (CDKs). Here we present the discovery and characterization of a covalent CDK7 inhibitor, THZ1, which has the unprecedented ability to target a remote cysteine residue located outside of the canonical kinase domain, providing an unanticipated means of achieving selectivity for CDK7.

A phase I study of escalated dose subcutaneous alemtuzumab given weekly with rituximab in relapsed chronic lymphocytic leukemia/small lymphocytic lymphoma.

This study assessed the safety and preliminary efficacy of escalated dose subcutaneous alemtuzumab in combination with rituximab in chronic lymphocytic leukemia. Twenty-eight patients with relapsed refractory chronic lymphocytic leukemia were treated on four dosing cohorts of weekly rituximab at 375 mg/m(2) and alemtuzumab doses that started at 30 mg three times per week and escalated to weekly dosing over four weeks, culminating with 90 mg weekly. One dose limiting toxicity of a rituximab infusion reaction was seen in cohort 2, but the regimen was otherwise well tolerated without evidence of differential toxicity by cohort.

Evolution and impact of subclonal mutations in chronic lymphocytic leukemia.

Clonal evolution is a key feature of cancer progression and relapse. We studied intratumoral heterogeneity in 149 chronic lymphocytic leukemia (CLL) cases by integrating whole-exome sequence and copy number to measure the fraction of cancer cells harboring each somatic mutation. We identified driver mutations as predominantly clonal (e.

Integrative genomic analysis implicates gain of PIK3CA at 3q26 and MYC at 8q24 in chronic lymphocytic leukemia.

Purpose: The disease course of chronic lymphocytic leukemia (CLL) varies significantly within cytogenetic groups. We hypothesized that high-resolution genomic analysis of CLL would identify additional recurrent abnormalities associated with short time-to-first therapy (TTFT).

Experimental Design: We undertook high-resolution genomic analysis of 161 prospectively enrolled CLLs using Affymetrix 6.

SF3B1 and other novel cancer genes in chronic lymphocytic leukemia.

Background: The somatic genetic basis of chronic lymphocytic leukemia, a common and clinically heterogeneous leukemia occurring in adults, remains poorly understood.

Methods: We obtained DNA samples from leukemia cells in 91 patients with chronic lymphocytic leukemia and performed massively parallel sequencing of 88 whole exomes and whole genomes, together with sequencing of matched germline DNA, to characterize the spectrum of somatic mutations in this disease.

Results: Nine genes that are mutated at significant frequencies were identified, including four with established roles in chronic lymphocytic leukemia (TP53 in 15% of patients, ATM in 9%, MYD88 in 10%, and NOTCH1 in 4%) and five with unestablished roles (SF3B1, ZMYM3, MAPK1, FBXW7, and DDX3X).

Aging impairs recipient T cell intrinsic and extrinsic factors in response to transplantation.

Background: As increasing numbers of older people are listed for solid organ transplantation, there is an urgent need to better understand how aging modifies alloimmune responses. Here, we investigated whether aging impairs the ability of donor dendritic cells or recipient immunity to prime alloimmune responses to organ transplantation.

Principal Findings: Using murine experimental models, we found that aging impaired the host environment to expand and activate antigen specific CD8(+) T cells.

Aging impairs IFN regulatory factor 7 up-regulation in plasmacytoid dendritic cells during TLR9 activation.

Plasmacytoid dendritic cells (pDCs) are innate sensors that produce IFN-alpha in response to viral infections. Determining how aging alters the cellular and molecular function of these cells may provide an explanation of increased susceptibility of older people to viral infections. Hence, we examined whether aging critically impairs pDC function during infection with HSV-2, a viral pathogen that activates TLR9.

Dual signaling of MyD88 and TRIF is critical for maximal TLR4-induced dendritic cell maturation.

TLR4 is a unique TLR because downstream signaling occurs via two separate pathways, as follows: MyD88 and Toll IL-1 receptor (TIR) domain-containing adaptor-inducing IFN-beta (TRIF). In this study, we compared and contrasted the interplay of these pathways between murine dendritic cells (DCs) and macrophages during LPS stimulation. During TLR4 activation, neither pathway on its own was critical for up-regulation of costimulatory molecules in DCs, whereas the up-regulation of costimulatory molecules was largely TRIF dependent in macrophages.

Acute allograft rejection occurs independently of inducible heat shock protein-70.

Dendritic cells (DCs) are key mediators of the innate response to transplantation. Yet, the substances that activate these cells during acute allograft rejection remain elusive. Previous work has suggested that heat shock protein (HSP)-70 is associated with acute allograft rejection.

Toll-like receptors and their role in transplantation.

The innate immune system is an ancient, conserved pathogen response system that lays the foundation for self/non-self discrimination. The cells of the innate immune system are responsible for recognizing the highly conserved molecular motifs of microbial pathogens and represent the first line of immunological defense as well as contributing to the activation of the adaptive immune response. Toll-like receptors are a family of 13 germline-encoded receptors on antigen presenting cells, T cells and various non-lymphoid tissues that are critically important for innate immune function and inflammatory responses.

Murine [corrected] myeloid dendritic cell-dependent toll-like receptor immunity is preserved with aging.

The immune response is the result of the interplay between innate and adaptive immunity, yet the impact of aging on this interaction is unclear. Addressing this fundamental question will be critical for the development of effective vaccines for the rapidly rising older subpopulation that manifests increased prevalence of malignancies and infections. Therefore, we undertook the current study to investigate whether aging impairs toll-like receptor (TLR) function in myeloid dendritic cells and whether this leads to reduced T-cell priming.

Absence of innate MyD88 signaling promotes inducible allograft acceptance.

Prior experimental strategies to induce transplantation tolerance have focused largely on modifying adaptive immunity. However, less is known concerning the role of innate immune signaling in the induction of transplantation tolerance. Using a highly immunogenic murine skin transplant model that resists transplantation tolerance induction when innate immunity is preserved, we show that absence of MyD88, a key innate Toll like receptor signal adaptor, abrogates this resistance and facilitates inducible allograft acceptance.

Direct antigen presentation by a xenograft induces immunity independently of secondary lymphoid organs.

The location of immune activation is controversial during acute allograft rejection and unknown in xenotransplantation. To determine where immune activation to a xenograft occurs, we examined whether splenectomized alymphoplastic mice that possess no secondary lymphoid organs can reject porcine skin xenografts. Our results show that these mice rejected their xenografts, in a T cell-dependent fashion, at the same tempo as wild-type recipients, demonstrating that xenograft rejection is not critically dependent on secondary lymphoid organs.

TH1 immune responses to fully MHC mismatched allografts are diminished in the absence of MyD88, a toll-like receptor signal adaptor protein.

Toll-like receptors (TLRs) are innate immune receptors that are critical for recognizing conserved microbial motifs by inducing TH1 immunity. The majority of TLRs utilize the adaptor protein MyD88 for signal transduction, although other adaptors have been recently described. As the role of innate immunity in transplantation is unclear, we examined the importance of the MyD88 pathway in acute rejection of fully MHC-mismatched murine allografts and specifically investigated whether MyD88 signaling is important for DC (dendritic cell) function and TH1 alloimmune responses.

Critical role of the Toll-like receptor signal adaptor protein MyD88 in acute allograft rejection.

The Toll-like receptors (TLRs) are recently discovered germline-encoded receptors on APCs that are critically important in innate immune recognition of microbial pathogens. However, their role in solid-organ transplantation is unknown. To explore this role, we employed a skin allograft model using mice with targeted deletion of the universal TLR signal adaptor protein, MyD88.