Molecular patterns of response and treatment failure after frontline venetoclax combinations in older patients with AML.

The BCL-2 inhibitor venetoclax combined with hypomethylating agents or low-dose cytarabine represents an important new therapy for older or unfit patients with acute myeloid leukemia (AML). We analyzed 81 patients receiving these venetoclax-based combinations to identify molecular correlates of durable remission, response followed by relapse (adaptive resistance), or refractory disease (primary resistance). High response rates and durable remissions were typically associated with NPM1 or IDH2 mutations, with prolonged molecular remissions prevalent for NPM1 mutations. Primary and adaptive resistance to venetoclax-based combinations was most commonly characterized by acquisition or enrichment of clones activating signaling pathways such as FLT3 or RAS or biallelically perturbing TP53. Single-cell studies highlighted the polyclonal nature of intratumoral resistance mechanisms in some cases. Among cases that were primary refractory, we identified heterogeneous and sometimes divergent interval changes in leukemic clones within a single cycle of therapy, highlighting the dynamic and rapid occurrence of therapeutic selection in AML. In functional studies, FLT3 internal tandem duplication gain or TP53 loss conferred cross-resistance to both venetoclax and cytotoxic-based therapies. Collectively, we highlight molecular determinants of outcome with clinical relevance to patients with AML receiving venetoclax-based combination therapies.

Glycaemic management during the inpatient enteral feeding of people with stroke and diabetes.

This paper is an abridged and modified version of guidelines produced by the Joint British Diabetes Societies for inpatient care on glycaemic management during the enteral feeding of people with stroke and diabetes. These were revised in 2017 and have been adapted specifically for Diabetic Medicine. The full version can be found at: www.diabetes.org.uk/joint-british-diabetes-society or https://abcd.care/joint-british-diabetes-societies-jbds-inpatient-care-group. Many people have both diabetes and an acute stroke, and a stanv dard approach to the management of people with stroke is the provision of adequate nutrition. Frequently, this involves a period of enteral feeding if there is impaired ability to swallow food safely. There is currently considerable variability in the management of people with diabetes fed enterally after a stroke, and the evidence base guiding diabetes management in this clinical situation is very weak, although poor glycaemic outcomes in people receiving enteral feeding after stroke may worsen recovery and cause harm. The aim of this document is to provide sensible clinical guidance in this area, written by a multidisciplinary team; this guideline had input from diabetes specialist nurses, diabetologists, dietitians, stroke physicians and pharmacists with expertise in this area, and from UK professional organizations. It is aimed at multidisciplinary teams managing people with stroke and diabetes who require enteral feeding. We recognize that there is limited clinical evidence in this area.

Enhancing venetoclax activity in acute myeloid leukemia by co-targeting MCL1.

Targeted therapies are frequently combined with standard cytotoxic drugs to enhance clinical response. Targeting the B-cell lymphoma 2 (BCL-2) family of proteins is an attractive option to combat chemoresistance in leukemia. Preclinical and clinical studies indicate modest single-agent activity with selective BCL-2 inhibitors (for example, venetoclax). We show that venetoclax synergizes with cytarabine and idarubicin to increase antileukemic efficacy in a TP53-dependent manner. Although TP53 deficiency impaired sensitivity to combined venetoclax and chemotherapy, higher-dose idarubicin was able to suppress MCL1 and induce cell death independently of TP53. Consistent with an MCL1-specific effect, cell death from high-dose idarubicin was dependent on pro-apoptotic Bak. Combining higher-dose idarubicin with venetoclax was able to partially overcome resistance in Bak-deficient cells. Using inducible vectors and venetoclax to differentially target anti-apoptotic BCL-2 family members, BCL-2 and MCL1 emerged as critical and complementary proteins regulating cell survival in acute myeloid leukemia. Dual targeting of BCL-2 and MCL1, but not either alone, prolonged survival of leukemia-bearing mice. In conclusion, our findings support the further investigation of venetoclax in combination with standard chemotherapy, including intensified doses of idarubicin. Venetoclax should also be investigated in combination with direct inhibitors of MCL1 as a chemotherapy-free approach in the future.

Targeting BCL2 With BH3 Mimetics: Basic Science and Clinical Application of Venetoclax in Chronic Lymphocytic Leukemia and Related B Cell Malignancies.

The intracellular protein B-cell-lymphoma-2 (BCL2) has been considered an attractive target for cancer therapy since the discovery of its function as a major promoter of cell survival (an anti-apoptotic) in the late 1980s. However, the challenges of targeting a protein-protein interaction delayed the discovery of fit-for-purpose molecules until the mid-2000s. Since then, a series of high affinity small organic molecules that inhibits the interaction of BCL2 with the apoptotic machinery, the so-called BH3-mimetics, have been developed. Venetoclax (formerly ABT-199) is the first to achieve US Food and Drug Administration approval, with an indication for treatment of patients with previously treated chronic lymphocytic leukemia (CLL) bearing deletion of the long arm of chromosome 17. Here, we review key aspects of the science underpinning the clinical application of BCL2 inhibitors and explore both our current knowledge and unresolved questions about its clinical utility, both in CLL and in other B-cell malignancies that highly express BCL2.

Nephrotic syndrome as a complication of chronic graft-versus-host disease after allogeneic haemopoietic stem cell transplantation.

Nephrotic syndrome (NS) is a rare complication following allogeneic haemopoietic stem cell transplantation (allo-HSCT), with limited current understanding of its pathogenesis. Here, we describe four cases of NS following allo-HSCT diagnosed at our institutions to identify key clinical and pathological features. In addition, a PubMed search was performed to identify existing reports that were pooled together with our cases for analysis. NS occurred as a late complication following allo-HSCT, with median onset 19.5 months after transplant (range: 3.9-84 months). The most common histopathology observed was membranous nephropathy; however, cases of minimal change disease have also been reported. There is a high incidence of prior extra-renal graft-versus-host disease (GvHD), with all four of our cases and 82% of published cases having prior GvHD. Glucocorticosteroids are the most common treatment, with variable degrees of response. Responses to immunosuppression with calcineurin inhibitors and rituximab have been described in steroid-refractory cases.

BET inhibition represses miR17-92 to drive BIM-initiated apoptosis of normal and transformed hematopoietic cells.

The BET (bromodomain and extraterminal domain) bromodomain-containing proteins, such as BRD4, are highly promising targets for treating lymphoid and myeloid malignancies. They act to modulate the expression of multiple genes that control diverse cellular processes including proliferation, survival and differentiation that are consequentially disrupted by small-molecule BET bromodomain inhibitors such as JQ1. By assessing the impact of these inhibitors on normal mouse hematopoietic cells or their transformed counterparts, we establish definitively that their cytotoxic action in vitro and in vivo relies predominantly on the activation of BAX/BAK-dependent mitochondrial (intrinsic) apoptosis. In large part, this is triggered by marked upregulation of the BH3-only protein BIM when the BET inhibitors suppress miR-17-92, a key post-transcriptional repressor of BIM expression. Thus, our study strongly suggests that mutations that permit the evasion of apoptosis (for example, BCL2 overexpression, BIM inactivation) are likely to blunt the activity of the BET bromodomain inhibitors and should be anticipated when therapy resistance develops. Strikingly, we also found that certain normal hematopoietic cells, especially those of lymphoid origin, are as prone to apoptosis induced by the BET inhibitors as their transformed counterparts, indicating that their susceptibility to BET inhibitors did not arise from oncogenic transformation.

Cellulose synthase gene expression profiling of Physcomitrella patens.

The cellulose synthase (CESA) gene family of seed plants comprises six clades that encode isoforms with conserved expression patterns and distinct functions in cellulose synthesis complex (CSC) formation and primary and secondary cell wall synthesis. In mosses, which have rosette CSCs like those of seed plants but lack lignified secondary cell walls, the CESA gene family diversified independently and includes no members of the six functionally distinct seed plant clades. There are seven CESA isoforms encoded in the genome of the moss Physcomitrella patens. However, only PpCESA5 has been characterised functionally, and little information is available on the expression of other PpCESA family members. We have profiled PpCESA expression through quantitative RT-PCR, analysis of promoter-reporter lines, and cluster analysis of public microarray data in an effort to identify expression and co-expression patterns that could help reveal the functions of PpCESA isoforms in protein complex formation and development of specific tissues. In contrast to the tissue-specific expression observed for seed plant CESAs, each of the PpCESAs was broadly expressed throughout most developing tissues. Although a few statistically significant differences in expression of PpCESAs were noted when some tissues and hormone treatments were compared, no strong co-expression patterns were observed. Along with CESA phylogenies and lack of single PpCESA mutant phenotypes reported elsewhere, broad overlapping expression of the PpCESAs indicates a high degree of inter-changeability and is consistent with a different pattern of functional specialisation in the evolution of the seed plant and moss CESA families.

Treatment of patients with multiple myeloma who are eligible for stem cell transplantation: position statement of the Myeloma Foundation of Australia Medical and Scientific Advisory Group.

The survival of patients with multiple myeloma (MM) has improved substantially since the introduction in the late 1980s of high-dose chemotherapy (HDT) supported by autologous stem cell transplantation (ASCT). Further improvements have been observed following the availability of immunomodulatory drugs (IMiD) such as thalidomide and lenalidomide, and the proteasome inhibitor, bortezomib. Here, we summarise the recommendations of the Medical Scientific Advisory Group to the Myeloma Foundation of Australia for patients considered suitable for HDT + ASCT as part of initial therapy. These recommendations incorporate the various phases of treatment: induction, HDT conditioning and maintenance therapy.

Management of systemic AL amyloidosis: recommendations of the Myeloma Foundation of Australia Medical and Scientific Advisory Group.

Systemic AL amyloidosis is a plasma cell dyscrasia with a characteristic clinical phenotype caused by multi-organ deposition of an amyloidogenic monoclonal protein. This condition poses a unique management challenge due to the complexity of the clinical presentation and the narrow therapeutic window of available therapies. Improved appreciation of the need for risk stratification, standardised use of sensitive laboratory testing for monitoring disease response, vigilant supportive care and the availability of newer agents with more favourable toxicity profiles have contributed to the improvement in treatment-related mortality and overall survival seen over the past decade. Nonetheless, with respect to the optimal management approach, there is a paucity of high-level clinical evidence due to the rarity of the disease, and enrollment in clinical trials is still the preferred approach where available. This review will summarise the Clinical Practice Guidelines on the Management of Systemic Light Chain (AL) Amyloidosis recently prepared by the Medical Scientific Advisory Group of the Myeloma Foundation of Australia. It is hoped that these guidelines will assist clinicians in better understanding and optimising the management of this difficult disease.

Targeting of acute myeloid leukemia in vitro and in vivo with an anti-CD123 mAb engineered for optimal ADCC.

Acute myeloid leukemia (AML) is a biologically heterogeneous group of related diseases in urgent need of better therapeutic options. Despite this heterogeneity, overexpression of the interleukin (IL)-3 receptor α-chain (IL-3 Rα/CD123) on both the blast and leukemic stem cell (LSC) populations is a common occurrence, a finding that has generated wide interest in devising new therapeutic approaches that target CD123 in AML patients. We report here the development of CSL362, a monoclonal antibody to CD123 that has been humanized, affinity-matured and Fc-engineered for increased affinity for human CD16 (FcγRIIIa). In vitro studies demonstrated that CSL362 potently induces antibody-dependent cell-mediated cytotoxicity of both AML blasts and CD34(+)CD38(-)CD123(+) LSC by NK cells. Importantly, CSL362 was highly effective in vivo reducing leukemic cell growth in AML xenograft mouse models and potently depleting plasmacytoid dendritic cells and basophils in cynomolgus monkeys. Significantly, we demonstrated CSL362-dependent autologous depletion of AML blasts ex vivo, indicating that CSL362 enables the efficient killing of AML cells by the patient's own NK cells. These studies offer a new therapeutic option for AML patients with adequate NK-cell function and warrant the clinical development of CSL362 for the treatment of AML.

Both leukaemic and normal peripheral B lymphoid cells are highly sensitive to the selective pharmacological inhibition of prosurvival Bcl-2 with ABT-199.

Overexpression of the prosurvival protein Bcl-2 marks many B-lymphoid malignancies and contributes to resistance to many commonly used chemotherapeutic agents. The first effective BH3 mimetic inhibitors of Bcl-2, ABT-737 and navitoclax, also target Bcl-xL, causing dose-limiting thrombocytopenia. This prompted the development of the Bcl-2-selective antagonist, ABT-199. Here we show that in lymphoid cells, ABT-199 specifically causes Bax/Bak-mediated apoptosis that is triggered principally by the initiator BH3-only protein Bim. As expected, malignant cells isolated from patients with chronic lymphocytic leukaemia are highly sensitive to ABT-199. However, we found that normal, untransformed mature B cells are also highly sensitive to ABT-199, both in vitro and in vivo. By contrast, the B-cell precursors are largely spared, as are cells of myeloid origin. These results pinpoint the probable impact of the pharmacological inhibition of Bcl-2 by ABT-199 on the normal mature haemopoietic cell lineages in patients, and have implications for monitoring during ABT-199 therapy as well as for the clinical utility of this very promising targeted agent.

GFI1B mutation causes a bleeding disorder with abnormal platelet function.

BACKGROUND: GFI1B is a transcription factor important for erythropoiesis and megakaryocyte development but previously unknown to be associated with human disease. METHODS: A family with a novel bleeding disorder was identified and characterized. Genetic linkage analysis and massively parallel sequencing were used to localize the mutation causing the disease phenotype on chromosome 9. Functional studies were then performed in megakaryocytic cell lines to determine the biological effects of the mutant transcript. RESULTS: We have identified a family with an autosomal dominant bleeding disorder associated with macrothrombocytopenia, red cell anisopoikilocytosis, and platelet dysfunction. The severity of bleeding is variable with some affected individuals experiencing spontaneous bleeding while other family members exhibit only abnormal bleeding with surgery. A single nucleotide insertion was identified in GFI1B that predicts a frameshift mutation in the fifth zinc finger DNA-binding domain. This mutation alters the transcriptional activity of the protein, resulting in a reduction in platelet α-granule content and aberrant expression of key platelet proteins. CONCLUSIONS: GFI1B mutation represents a novel human bleeding disorder, and the described phenotype identifies GFI1B as a critical regulator of platelet shape, number, and function.

The equivalents of human blood and spleen dendritic cell subtypes can be generated in vitro from human CD34(+) stem cells in the presence of fms-like tyrosine kinase 3 ligand and thrombopoietin.

Dendritic cells (DCs) are immune cells specialized to capture, process and present antigen to T cells in order to initiate an appropriate adaptive immune response. The study of mouse DC has revealed a heterogeneous population of cells that differ in their development, surface phenotype and function. The study of human blood and spleen has shown the presence of two subsets of conventional DC including the CD1b/c(+) and CD141(+)CLEC9A(+) conventional DC (cDC) and a plasmacytoid DC (pDC) that is CD304(+)CD123(+). Studies on these subpopulations have revealed phenotypic and functional differences that are similar to those described in the mouse. In this study, the three DC subsets have been generated in vitro from human CD34(+) precursors in the presence of fms-like tyrosine kinase 3 ligand (Flt3L) and thrombopoietin (TPO). The DC subsets so generated, including the CD1b/c(+) and CLEC9A(+) cDCs and CD123(+) pDCs, were largely similar to their blood and spleen counterparts with respect to surface phenotype, toll-like receptor and transcription factor expression, capacity to stimulate T cells, cytokine secretion and cross-presentation of antigens. This system may be utilized to study aspects of DC development and function not possible in vivo.

Translation inhibitors induce cell death by multiple mechanisms and Mcl-1 reduction is only a minor contributor.

There is significant interest in treating cancers by blocking protein synthesis, to which hematological malignancies seem particularly sensitive. The translation elongation inhibitor homoharringtonine (Omacetaxine mepesuccinate) is undergoing clinical trials for chronic myeloid leukemia, whereas the translation initiation inhibitor silvestrol has shown promise in mouse models of cancer. Precisely how these compounds induce cell death is unclear, but reduction in Mcl-1, a labile pro-survival Bcl-2 family member, has been proposed to constitute the critical event. Moreover, the contribution of translation inhibitors to neutropenia and lymphopenia has not been precisely defined. Herein, we demonstrate that primary B cells and neutrophils are highly sensitive to translation inhibitors, which trigger the Bax/Bak-mediated apoptotic pathway. However, contrary to expectations, reduction of Mcl-1 did not significantly enhance cytotoxicity of these compounds, suggesting that it does not have a principal role and cautions that strong correlations do not always signify causality. On the other hand, the killing of T lymphocytes was less dependent on Bax and Bak, indicating that translation inhibitors can also induce cell death via alternative mechanisms. Indeed, loss of clonogenic survival proved to be independent of the Bax/Bak-mediated apoptosis altogether. Our findings warn of potential toxicity as these translation inhibitors are cytotoxic to many differentiated non-cycling cells.

Psoas abscess formation in suboptimally controlled diabetes mellitus.

Psoas abscess formation is a rare entity for which diabetes mellitus remains a major predisposing factor. Diabetes has long been associated with a predisposition to unusual and more serious infections. Here we present two cases that demonstrate that chronically suboptimally controlled diabetes remains an important marker for the development of primary psoas abscess. It is important to include psoas abscess in the differential in such patients to ensure early diagnosis and treatment.

Low-intensity exercise enhances expression of markers of alternative activation in circulating leukocytes: roles of PPARγ and Th2 cytokines.

OBJECTIVE: Pharmacological activation of the nuclear receptor PPARγ is linked to numerous beneficial effects in the contexts of inflammation, lipid homeostasis, Type-2 Diabetes (T2D) and atherosclerosis. These beneficial effects include priming of circulating monocytes for differentiation towards an 'alternative' anti-inflammatory M2 macrophage phenotype. As we have recently shown that participation in low-intensity exercise increases PPARγ expression and activity in leukocytes from previously sedentary individuals, we aimed to elucidate whether low-intensity exercise elicited a pattern of gene expression similar to that reported for M2 monocyte-macrophage differentiation. METHODS: 17 sedentary individuals undertook an 8-week low-intensity exercise programme (walking 10,000steps/day, three times/week). Changes in expression of PPARs and the PPARγ co-activators PGC-1α and PGC-1ß; Th2 (IL-4; IL-10) and Th1 (IL-6) cytokines; and markers for the M2 (AMAC1, CD14, MR, IL-4) and the 'classical' pro-inflammatory M1 (MCP-1, TNFα, IL-6) phenotypes, were determined using RT-PCR (to assess leukocyte mRNA expression) and ELISA (to assess plasma cytokine levels). RESULTS: Exercise was associated with upregulation of M2 markers, PGC-1α and PGC-1ß, and with downregulation of M1 markers. Moreover, plasma levels of Th2 cytokines increased after exercise, while those of Th1 cytokines decreased. However, other PPARs (PPARα; PPARß/δ) did not undergo marked exercise-induced activation or upregulation. Thus, participation in low-intensity exercise may prime monocytes for differentiation towards an M2 macrophage phenotype via PPARγ/PGC-1α/ß. CONCLUSION: Given the similarities between these effects and pharmacologically induced M2 polarisation, we propose that exercise-induced PPARγ/PGC-1α/ß-mediated M2 polarisation may constitute a novel anti-inflammatory benefit of low-intensity exercise.

The BH3 mimetic compound, ABT-737, synergizes with a range of cytotoxic chemotherapy agents in chronic lymphocytic leukemia.

As chronic lymphocytic leukemia (CLL) is characterized by overexpression of pro-survival BCL2, compounds that mimic its physiological antagonists, the BH3-only proteins, may have a role in treatment of this disease. ABT-737 is a BH3 mimetic compound that selectively targets BCL2 and BCLX(L). In the present work, we report that ABT-737 is highly effective (LC(50)<50 nM) as a single agent against most (21/30) primary CLL samples, but that a sizable minority is relatively insensitive. In vitro sensitivity to ABT-737 could not be simply predicted by the patients' clinical features, including response to prior therapy or known prognostic markers (CD38 expression, 17p deletion), or the relative expression of BCL2 family proteins (BCL2, MCL1, BAX, BIM). Strikingly, co-incubation with cytotoxic agents (dexamethasone, etoposide, fludarabine, doxorubicin) sensitized most CLL samples to ABT-737, but this could not be predicted by responses to either ABT-737 or the cytotoxic agent alone. Of 17 samples least sensitive to ABT-737, 13 were sensitized by co-treatment with at least one cytotoxic agent. These data indicate that combination of ABT-737 with a second anti-leukemic agent would improve response rates and suggest a potential role for combination therapies that include BH3 mimetics for the treatment of this disease.

Lower-crustal intrusion on the North Atlantic continental margin.

When continents break apart, the rifting is sometimes accompanied by the production of large volumes of molten rock. The total melt volume, however, is uncertain, because only part of it has erupted at the surface. Furthermore, the cause of the magmatism is still disputed-specifically, whether or not it is due to increased mantle temperatures. We recorded deep-penetration normal-incidence and wide-angle seismic profiles across the Faroe and Hatton Bank volcanic margins in the northeast Atlantic. Here we show that near the Faroe Islands, for every 1 km along strike, 360-400 km(3) of basalt is extruded, while 540-600 km(3) is intruded into the continent-ocean transition. We find that lower-crustal intrusions are focused mainly into a narrow zone approximately 50 km wide on the transition, although extruded basalts flow more than 100 km from the rift. Seismic profiles show that the melt is intruded into the lower crust as sills, which cross-cut the continental fabric, rather than as an 'underplate' of 100 per cent melt, as has often been assumed. Evidence from the measured seismic velocities and from igneous thicknesses are consistent with the dominant control on melt production being increased mantle temperatures, with no requirement for either significant active small-scale mantle convection under the rift or the presence of fertile mantle at the time of continental break-up, as has previously been suggested for the North Atlantic Ocean.

Cyclosporin, methotrexate and prednisolone for graft-versus-host disease prophylaxis in allogeneic peripheral blood progenitor cell transplants.

The utility of GVHD prophylaxis with cyclosporin, MTX and prednisolone (CSA/MTX/Pred) in allogeneic PBPC transplants is not well described although there are published data using this combination after bone marrow transplants. The effectiveness of this regimen on the prevention of GVHD was assessed in 107 consecutive sibling and less-than-ideal donor transplant recipients over a 5-year period and compared to that observed in 65 patients receiving standard CSA and short-course MTX without prednisolone. Oral prednisolone was commenced on day +14 at 0.5 mg/kg per day, increased to 1 mg/kg per day on day +21 to day +34 then gradually tapered and ceased by day +100. The cumulative incidence of acute GVHD (grades II-IV) to day 100 in those receiving prednisolone prophylaxis was lower (52 versus 76%, P<0.01). The onset of symptomatic GVHD requiring systemic treatment was delayed from a median of 41 days post transplant to 92 days. When assessment of the cumulative incidence of symptomatic GVHD continued to day +180 incidence became similar (74 versus 78%), there was no difference between the two groups in rates of relapse, transplant-related mortality, infections or chronic GVHD. We conclude that the addition of prednisolone to CSA/MTX delays the onset of early acute GVHD in PBPC recipients but has no impact on the overall incidence of GVHD.