ORCID Profile
0000-0001-9690-0879
Current Organisations
Royal Melbourne Hospital
,
Walter and Eliza Hall Institute of Medical Research
,
Peter MacCallum Cancer Centre
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 13-06-2020
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 11-11-2023
DOI: 10.1111/EJH.13890
Abstract: Multi‐parametric flow cytometry (MFC) has a well‐established role in measurable residual disease (MRD) monitoring in patients with B‐lymphoblastic leukemia (B‐ALL). However, the optimal time‐point (TP) for early MRD testing and associated prognostic impact remain undefined in adult B‐ALL patients receiving Hyper‐CVAD induction chemotherapy. To evaluate the utility of MRD analysis after one cycle (TP1) in comparison to MRD analysis after two cycles (TP2) of induction treatment with Hyper‐CVAD chemotherapy, we studied 49 adult B‐ALL patients over a 10‐year period (2010–2020) who had available bone marrow s les for morphological and MFC MRD assessments at the two separate TPs. Median times to TP1 and TP2 relative to start of treatment were 21 and 45 days, respectively. When censored at transplant, achievement of MRD negativity at TP1 was not associated with a statistically significant improvement in either event‐free survival (EFS) ( p = .426) or overall survival (OS) ( p = .335) when compared to patients with MRD positivity. In contrast, achieving MRD negativity at TP2 was associated with a statistically significant improvement in both EFS ( p = ·005) and OS ( p = .047) over patients who remained MRD positive. Multivariate analysis demonstrated that KMT2A ‐rearrangement and MRD positivity at TP2 were the only significant predictors of outcome, correlating with worse EFS and OS. Therefore, in the absence of residual morphologic disease, MRD analysis after one cycle of Hyper‐CVAD induction chemotherapy did not provide additional benefit with regard to risk stratification or correlation with survival outcomes when compared to MRD testing after two cycles of Hyper‐CVAD in adult B‐ALL patients.
Publisher: Springer Science and Business Media LLC
Date: 07-10-2019
Publisher: Research Square Platform LLC
Date: 27-10-2023
Publisher: Springer Science and Business Media LLC
Date: 25-08-2022
Publisher: Springer Science and Business Media LLC
Date: 16-04-2015
Abstract: Navitoclax (ABT-263), an inhibitor of the pro-survival BCL-2 family proteins BCL-2, BCL-X L and BCL-W, has shown clinical efficacy in certain BCL-2-dependent haematological cancers, but causes dose-limiting thrombocytopaenia. The latter effect is caused by Navitoclax directly inducing the apoptotic death of platelets, which are dependent on BCL-X L for survival. Recently, ABT-199, a selective BCL-2 antagonist, was developed. It has shown promising anti-leukaemia activity in patients whilst sparing platelets, suggesting that the megakaryocyte lineage does not require BCL-2. In order to elucidate the role of BCL-2 in megakaryocyte and platelet survival, we generated mice with a lineage-specific deletion of Bcl2 , alone or in combination with loss of Mcl1 or Bclx . Platelet production and platelet survival were analysed. Additionally, we made use of BH3 mimetics that selectively inhibit BCL-2 or BCL-X L . We show that the deletion of BCL-2, on its own or in concert with MCL-1, does not affect platelet production or platelet lifespan. Thrombocytopaenia in Bclx -deficient mice was not affected by additional genetic loss or pharmacological inhibition of BCL-2. Thus, BCL-2 is dispensable for thrombopoiesis and platelet survival in mice.
Publisher: Cold Spring Harbor Laboratory
Date: 30-05-2020
DOI: 10.1101/2020.05.28.120188
Abstract: Extrinsic regulation of single haematopoietic stem and progenitor cell (HSPC) fate is crucial for immune cell development. Here, we examine the aetiology of Flt3 ligand (Flt3L)-mediated emergency development of type 1 conventional dendritic cells (cDC1s), which results in enhanced immunity against infections and cancer. Using cellular barcoding, we demonstrate a predominant role of enhanced clonal expansion and moderate contribution via recruitment of additional cDC1-generating HSPCs. The selective cDC1 expansion occurs primarily via multi-/oligo-potent clones, without compromising output to other lineages. To understand the molecular hallmarks early during a Flt3L response, we develop Divi-Seq to simultaneously profile cell ision history, surface phenotype and transcriptional state of single HSPCs. We discover that Flt3L-responsive HSPCs maintain a proliferative ‘early progenitor’-like state, which leads to selective emergence of CD11c + cKit + transitional precursors with high cellular output to cDC1s. These findings inform the mechanistic action of Flt3L in natural immunity and immunotherapy at a clonal level.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1111/JTH.13843
Abstract: Essentials The phenotypes of different growth factor-independent 1B (GFI1B) variants are not established. GFI1B variants produce heterogeneous clinical phenotypes dependent on the site of mutation. Mutation of the first non-DNA-binding zinc-finger causes a mild platelet and clinical phenotype. GFI1B regulates the CD34 promoter platelet CD34 expression is an indicator of GFI1B mutation. Background Mutation of the growth factor-independent 1B (GFI1B) fifth DNA-binding zinc-finger domain causes macrothrombocytopenia and α-granule deficiency leading to clinical bleeding. The phenotypes associated with GFI1B variants disrupting non-DNA-binding zinc-fingers remain uncharacterized. Objectives To determine the functional and phenotypic consequences of GFI1B variants disrupting non-DNA-binding zinc-finger domains. Methods The GFI1B C168F variant and a novel GFI1B c.2520 + 1_2520 + 8delGTGGGCAC splice variant were identified in four unrelated families. Phenotypic features, DNA-binding properties and transcriptional effects were determined and compared with those in in iduals with a GFI1B H294 fs mutation of the fifth DNA-binding zinc-finger. Patient-specific induced pluripotent stem cell (iPSC)-derived megakaryocytes were generated to facilitate disease modeling. Results The DNA-binding GFI1B variant C168F, which is predicted to disrupt the first non-DNA-binding zinc-finger domain, is associated with macrothrombocytopenia without α-granule deficiency or bleeding symptoms. A GFI1B splice variant, c.2520 + 1_2520 + 8delGTGGGCAC, which generates a short GFI1B isoform that lacks non-DNA-binding zinc-fingers 1 and 2, is associated with increased platelet CD34 expression only, without quantitative or morphologic platelet abnormalities. GFI1B represses the CD34 promoter, and this repression is attenuated by different GFI1B zinc-finger mutations, suggesting that deregulation of CD34 expression occurs at a direct transcriptional level. Patient-specific iPSC-derived megakaryocytes phenocopy these observations. Conclusions Disruption of GFI1B non-DNA-binding zinc-finger 1 is associated with mild to moderate thrombocytopenia without α-granule deficiency or bleeding symptomatology, indicating that the site of GFI1B mutation has important phenotypic implications. Platelet CD34 expression appears to be a common feature of perturbed GFI1B function, and may have diagnostic utility.
Publisher: Informa UK Limited
Date: 05-03-2013
Publisher: Springer Science and Business Media LLC
Date: 08-02-2023
DOI: 10.1038/S41418-023-01119-Y
Abstract: The importance of c-MYC in regulating lymphopoiesis and promoting lymphomagenesis is well-established. Far less appreciated is the vital supporting role of MYC’s relative MNT. Using Rag1Cr e-mediated Mnt deletion in lymphoid progenitor cells, we show here that, during normal T cell development, MNT loss enhances apoptosis, at least in part by elevating expression of the pro-apoptotic BH3-only protein BIM. Moreover, using T lymphoma-prone VavP- MYC transgenic mice, we show that Mnt deletion reduces the pool of pre-malignant MYC-driven T lymphoid cells and abrogates thymic T lymphomagenesis. In addition, we establish that Mnt deletion prevents T lymphoma development in γ-irradiated mice, most likely by enhancing apoptosis of T lymphoid cells repopulating the depleted thymus. Taken together with our recent demonstration that MNT is vital for the survival of MYC-driven pre-malignant and malignant B lymphoid cells, these results suggest that MNT represents an important new drug target for both T and B lymphoid malignancies.
Publisher: Springer Science and Business Media LLC
Date: 03-2021
Publisher: Wiley
Date: 16-04-2009
DOI: 10.1111/J.1445-5994.2008.01637.X
Abstract: Thrombotic thrombocytopenic purpura (TTP) is a rare condition characterized by microangiopathic haemolytic anaemia, thrombocytopenia, renal and/or neurological dysfunction secondary to microvascular or macrovascular thrombosis. Despite advances in treatment, TTP remains a serious condition with significant morbidity and mortality. We undertook an audit of patients with TTP over 14 years to assess remission, relapse, survival and factors predictive of outcome using current therapy based on plasma exchange with fresh-frozen plasma. Forty patients were identified between January 1992 and December 2005. Thirty-one (82%) achieved complete response (CR) to therapy using plasma exchange with fresh-frozen plasma (median 11 exchanges) and steroids. Twelve (37%) relapsed a median of 14 days following cessation of therapy, with multiple relapses occurring in two patients. TTP-related death occurred in four patients during their initial presentation and in two during subsequent relapse. Four patients were only partially responsive to first-line therapy. The absence of neurological features at presentation was the only factor predicting a sustained CR to first-line therapy (P = 0.027, log-rank analysis). The mean duration of inpatient treatment was 18 days (range 4-38 days) with 30% of patients requiring intensive care admission. Thirty-four per cent of patients acquired central venous line infection, with a median of two episodes of line sepsis per patient. Our results indicate the need for better treatments to reduce the high early relapse rate and significant mortality associated with current therapy.
Publisher: Informa UK Limited
Date: 2007
DOI: 10.1080/10428190601099965
Abstract: Residual 2-fluoro-2-deoxyglucose (FDG) - positron emission tomography (PET) positivity during treatment of patients with diffuse large B-cell lymphoma (DLBLC) prospectively identifies a subgroup at high likelihood of subsequent treatment failure. A single institution clinical audit of FDG-PET performance for this indication was undertaken for patients with DLBCL treated with anthracycline-based chemotherapy +/- radiotherapy. Of 45 eligible patients, 14 (31%) were PET-positive after a median of three chemotherapy cycles (range 1 - 5), of which 10 (71%) progressed at a median of 6.5 months. An interim positive PET was a statistically significant adverse prognostic factor for treatment failure (P < 0.0001, log-rank analysis) with a hazard ratio for a positive interim-treatment PET of 9 (95% confidence interval = 4 - 55) and positive predictive value of 71% and negative predictive value of 90%. Notably, four patients with low-grade FDG-avidity limited to sites previously involved by biopsy-proven osseous lymphoma, remain progression-free (median follow-up 62 months). Low-grade FDG-avidity on interim restaging at sites of bone involvement by DLBCL at diagnosis, appears to be less predictive of disease progression than residual nodal or extra-nodal soft tissue abnormality by PET.
Publisher: American Society of Hematology
Date: 11-02-2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2009
Publisher: Elsevier BV
Date: 09-2016
Publisher: Proceedings of the National Academy of Sciences
Date: 27-12-2011
Abstract: Diverse mutations in the genes encoding hemoglobin (Hb) have been characterized in human disease. We describe here a mutation in the mouse Hbb-b2 gene, denoted Plt12 , that precisely mimics the human hemoglobin Hotel Dieu variant. The mutation results in increased affinity of Hb for oxygen and Plt12 mutant mice exhibited reduced partial pressure of O 2 in the blood, accompanied by erythrocytosis characterized by elevated erythropoietin levels and splenomegaly with excess erythropoiesis. Most homozygous Hbb-b2 Plt12/Plt12 mice succumbed to early lethality associated with emphysema, cardiac abnormalities, and liver degeneration. Survivors displayed a marked thrombocytopenia without significant deficiencies in the numbers of megakaryocytes or megakaryocyte progenitor cells. The lifespan of platelets in the circulation of Hbb-b2 Plt12/Plt12 mice was normal, and splenectomy did not correct the thrombocytopenia, suggesting that increased sequestration was unlikely to be a major contributor. These data, together with the observation that megakaryocytes in Hbb-b2 Plt12/Plt12 mice appeared smaller and deficient in cytoplasm, support a model in which hypoxia causes thrombocytopenia as a consequence of an inability of megakaryocytes, once formed, to properly mature and produce sufficient platelets. The Plt12 mouse is a model of high O 2 -affinity hemoglobinopathy and provides insights into hematopoiesis under conditions of chronic hypoxia.
Publisher: Proceedings of the National Academy of Sciences
Date: 30-08-2010
Abstract: Murine hematopoietic blast colony-forming cells (BL-CFCs) are able to generate up to 30,000 progeny blast cells within 10 d in agar cultures. Contained in these populations are large numbers of lineage-committed progenitor cells in the granulocytic and macrophage lineages. Sequential analyses of blast colonies revealed that self-generation of BL-CFCs occurs but is surprisingly late in clonal expansion, as is the emergence of progenitor cells committed to megakaryocytic and eosinophil lineages. Self-generating BL-CFCs were highly enriched in lineage − Kit + Sca1 + CD34 − Flt3R − populations, and colonies generated by such cells contained colony-forming units–spleen and formed erythroid and lymphoid progeny in vivo. The data suggest the existence of a hierarchical structure in BL-CFC populations with at least a subset being cells assayable as colony-forming units–spleen. Because BL-CFCs can self-generate and are able to generate lymphoid and myeloid populations, BL-CFCs appear to be ideal cells in which to analyze the processes of self-generation and lineage commitment in clonal in vitro cultures.
Publisher: Proceedings of the National Academy of Sciences
Date: 26-03-2013
Abstract: To define genetic lesions driving leukemia, we targeted cre-dependent Sleeping Beauty (SB) transposon mutagenesis to the blood-forming system using a hematopoietic-selective vav 1 oncogene ( vav1 ) promoter. Leukemias of erse lineages ensued, most commonly lymphoid leukemia and erythroleukemia. The inclusion of a transgenic allele of Janus kinase 2 ( JAK2 ) V617F resulted in acceleration of transposon-driven disease and strong selection for erythroleukemic pathology with transformation of bipotential erythro-megakaryocytic cells. The genes encoding the E-twenty-six (ETS) transcription factors Ets related gene (Erg) and Ets1 were the most common sites for transposon insertion in SB-induced JAK2V617F -positive erythroleukemias, present in 87.5% and 65%, respectively, of independent leukemias examined. The role of activated Erg was validated by reproducing erythroleukemic pathology in mice transplanted with fetal liver cells expressing translocated in liposarcoma ( TLS ) -ERG , an activated form of ERG found in human leukemia. Via application of SB mutagenesis to TLS-ERG –induced erythroid transformation, we identified multiple loci as likely collaborators with activation of Erg . Jak2 was identified as a common transposon insertion site in TLS-ERG –induced disease, strongly validating the cooperation between JAK2V617F and transposon insertion at the Erg locus in the JAK2V617F -positive leukemias. Moreover, loci expressing other regulators of signal transduction pathways were conspicuous among the common transposon insertion sites in TLS-ERG –driven leukemia, suggesting that a key mechanism in erythroleukemia may be the collaboration of lesions disturbing erythroid maturation, most notably in genes of the ETS family, with mutations that reduce dependence on exogenous signals.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1111/JTH.12368
Abstract: GFI1B is a transcription factor important for erythropoiesis and megakaryocyte development but previously unknown to be associated with human disease. 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. 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 in iduals 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. GFI1B mutation represents a novel human bleeding disorder, and the described phenotype identifies GFI1B as a critical regulator of platelet shape, number, and function.
Publisher: Springer Science and Business Media LLC
Date: 30-03-2023
DOI: 10.1038/S41590-023-01473-6
Abstract: Missense mutations in PLCG2 can cause autoinflammation with phospholipase C gamma 2-associated antibody deficiency and immune dysregulation (APLAID). Here, we generated a mouse model carrying an APLAID mutation (p.Ser707Tyr) and found that inflammatory infiltrates in the skin and lungs were only partially ameliorated by removing inflammasome function via the deletion of caspase-1. Also, deleting interleukin-6 or tumor necrosis factor did not fully prevent APLAID mutant mice from autoinflammation. Overall, these findings are in accordance with the poor response in iduals with APLAID have to treatments that block interleukin-1, JAK1/2 or tumor necrosis factor. Cytokine analysis revealed increased granulocyte colony-stimulating factor (G-CSF) levels as the most distinct feature in mice and in iduals with APLAID. Remarkably, treatment with a G-CSF antibody completely reversed established disease in APLAID mice. Furthermore, excessive myelopoiesis was normalized and lymphocyte numbers rebounded. APLAID mice were also fully rescued by bone marrow transplantation from healthy donors, associated with reduced G-CSF production, predominantly from non-hematopoietic cells. In summary, we identify APLAID as a G-CSF-driven autoinflammatory disease, for which targeted therapy is feasible.
Publisher: Proceedings of the National Academy of Sciences
Date: 30-01-2012
Abstract: Hematopoietic progenitor cells are the progeny of hematopoietic stem cells that coordinate the production of precise numbers of mature blood cells of erse functional lineages. Identification of cell-surface antigen expression associated with hematopoietic lineage restriction has allowed prospective isolation of progenitor cells with defined hematopoietic potential. To clarify further the cellular origins of megakaryocyte commitment, we assessed the in vitro and in vivo megakaryocyte and platelet potential of defined progenitor populations in the adult mouse bone marrow. We show that megakaryocytes arise from CD150 + bipotential progenitors that display both platelet- and erythrocyte-producing potential in vivo and that can develop from the Flt3 − fraction of the pregranulocyte-macrophage population. We define a bipotential erythroid-megakaryocyte progenitor population, the CD150 + CD9 lo endoglin lo fraction of Lin − cKit + IL7 receptor alpha − FcγRII/III lo Sca1 − cells, which contains the bulk of the megakaryocyte colony-forming capacity of the bone marrow, including bipotential megakaryocyte-erythroid colony-forming capacity, and can generate both erythrocytes and platelets efficiently in vivo. This fraction is distinct from the CD150 + CD9 hi endoglin lo fraction, which contains bipotential precursors with characteristics of increased megakaryocytic maturation, and the CD150 + CD9 lo endoglin hi fraction, which contains erythroid lineage-committed cells. Finally, we demonstrate that bipotential erythroid-megakaryocyte progenitor and CD150 + CD9 hi endoglin lo cells are TPO-responsive and that the latter population specifically expands in the recovery from thrombocytopenia induced by anti-platelet serum.
Publisher: American Society of Hematology
Date: 16-03-2023
Abstract: Polycythemia Vera (PV) is a myeloproliferative neoplasm driven by activating mutations in JAK2 that result in unrestrained erythrocyte production, increasing patients' hematocrit and hemoglobin concentration, placing them at risk of life-threatening thrombotic events. Our GWAS of 440 PV cases and 403,351 controls utilizing UK Biobank data found that SNPs in HFE known to cause hemochromatosis are highly associated with PV diagnosis, linking iron regulation to PV. Analysis of the FinnGen dataset independently confirmed over-representation of homozygous HFE variants in PV patients. HFE influences the expression of hepcidin, the master regulator of systemic iron homeostasis. Through genetic dissection of PV mouse models, we show that the PV erythroid phenotype is directly linked to hepcidin expression: endogenous hepcidin upregulation alleviates erythroid disease whereas hepcidin ablation worsens it. Further, we demonstrate that in PV, hepcidin is not regulated by expanded erythropoiesis but is likely governed by inflammatory cytokines signaling via GP130 coupled receptors. These findings have important implications for understanding the pathophysiology of PV and offer new therapeutic strategies for this disease.
Publisher: American Society of Hematology
Date: 11-04-2019
Publisher: Springer Science and Business Media LLC
Date: 05-09-2018
Publisher: American Society of Hematology
Date: 16-02-2018
DOI: 10.1182/BLOODADVANCES.2017013243
Abstract: Overexpression of Hhex transcription factor blocks myeloid differentiation at the promyelocyte stage. Hhex cooperates with growth factor independence to elicit rapid promyelocytic leukemia in mice.
Publisher: Springer Science and Business Media LLC
Date: 02-11-2017
DOI: 10.1038/S41598-017-15023-2
Abstract: Thrombopoietin (TPO) is the master cytokine regulator of megakaryopoiesis. In addition to regulation of megakaryocyte and platelet number, TPO is important for maintaining proper hematopoietic stem cell (HSC) function. It was previously shown that a number of lymphoid genes were upregulated in HSCs from Tpo −/− mice. We investigated if absent or enhanced TPO signaling would influence normal B-lymphopoiesis. Absent TPO signaling in Mpl −/− mice led to enrichment of a common lymphoid progenitor (CLP) signature in multipotential lineage-negative Sca-1 + c-Kit + (LSK) cells and an increase in CLP formation. Moreover, Mpl −/− mice exhibited increased numbers of PreB2 and immature B-cells in bone marrow and spleen, with an increased proportion of B-lymphoid cells in the G1 phase of the cell cycle. Conversely, elevated TPO signaling in Tpo Tg mice was associated with reduced B-lymphopoiesis. Although at steady state, peripheral blood lymphocyte counts were normal in both models, Mpl −/− Eµ- myc mice showed an enhanced preneoplastic phase with increased numbers of splenic PreB2 and immature B-cells, a reduced quiescent fraction, and augmented blood lymphocyte counts. Thus, although Mpl is not expressed on lymphoid cells, TPO signaling may indirectly influence B-lymphopoiesis and the preneoplastic state in Myc -driven B-cell lymphomagenesis by lineage priming in multipotential progenitor cells.
Publisher: Informa UK Limited
Date: 24-10-2012
DOI: 10.3109/10428194.2012.734615
Abstract: The understanding of myeloproliferative neoplasms has changed dramatically since Dameshek proposed his classification over 50 years ago. Our knowledge of the types of cells which constitute the hematopoietic system and of how they are regulated has also appreciated significantly over this time. This review relates what is currently known about the acquired genetic mutations associated with adult myeloproliferative neoplasms to how they lead to the hematopoietic perturbations of myeloproliferative disease. There is a particular focus on how stem and progenitor cell compartments are affected by BCR-ABL1 and JAK2V617F mutations, and the particular issue of resistance of leukemic stem cells to conventional and targeted therapies.
Publisher: Oxford University Press (OUP)
Date: 09-2020
Abstract: RNA-seq datasets can contain millions of intron reads per library that are typically removed from downstream analysis. Only reads overlapping annotated exons are considered to be informative since mature mRNA is assumed to be the major component sequenced, especially for poly(A) RNA libraries. In this study, we show that intron reads are informative, and through exploratory data analysis of read coverage that intron signal is representative of both pre-mRNAs and intron retention. We demonstrate how intron reads can be utilized in differential expression analysis using our index method where a unique set of differentially expressed genes can be detected using intron counts. In exploring read coverage, we also developed the superintronic software that quickly and robustly calculates user-defined summary statistics for exonic and intronic regions. Across multiple datasets, superintronic enabled us to identify several genes with distinctly retained introns that had similar coverage levels to that of neighbouring exons. The work and ideas presented in this paper is the first of its kind to consider multiple biological sources for intron reads through exploratory data analysis, minimizing bias in discovery and interpretation of results. Our findings open up possibilities for further methods development for intron reads and RNA-seq data in general.
Publisher: Research Square Platform LLC
Date: 15-04-2022
DOI: 10.21203/RS.3.RS-1555936/V1
Abstract: The importance of c-MYC in regulating normal lymphopoiesis and promoting lymphomagenesis is well-established, but far less appreciated is the vital supporting role of MYC’s relative MNT. We show here that, during normal T cell development, MNT loss enhances apoptosis and establish the mechanism as elevated expression of the pro-apoptotic BH3-only protein BIM. Using a MYC transgenic mouse model, we also show that MNT loss reduces the pool of premalignant MYC-driven T cells and totally abrogates thymic T lymphomagenesis. Taken together with our recent demonstration that MNT is vital for the survival of MYC-driven premalignant and malignant B lymphoid cells, these results suggest that MNT represents an important new drug target for both T and B lymphoid malignancies.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2019
Publisher: Public Library of Science (PLoS)
Date: 14-05-2015
Publisher: Springer Science and Business Media LLC
Date: 28-09-2023
Publisher: Oxford University Press (OUP)
Date: 05-11-2018
DOI: 10.1093/NAR/GKY1020
Publisher: Cold Spring Harbor Laboratory
Date: 06-2018
Abstract: Activating JAK2 point mutations are implicated in the pathogenesis of myeloid and lymphoid malignancies, including high-risk B-cell acute lymphoblastic leukemia (B-ALL). In preclinical studies, treatment of JAK2 mutant leukemias with type I JAK2 inhibitors (e.g., Food and Drug Administration [FDA]-approved ruxolitinib) provided limited single-agent responses, possibly due to paradoxical JAK2 Y1007/1008 hyperphosphorylation induced by these agents. To determine the importance of mutant JAK2 in B-ALL initiation and maintenance, we developed unique genetically engineered mouse models of B-ALL driven by overexpressed Crlf2 and mutant Jak2, recapitulating the genetic aberrations found in human B-ALL. While expression of mutant Jak2 was necessary for leukemia induction, neither its continued expression nor enzymatic activity was required to maintain leukemia survival and rapid proliferation. CRLF2/JAK2 mutant B-ALLs with sustained depletion or pharmacological inhibition of JAK2 exhibited enhanced expression of c-Myc and prominent up-regulation of c-Myc target genes. Combined indirect targeting of c-Myc using the BET bromodomain inhibitor JQ1 and direct targeting of JAK2 with ruxolitinib potently killed JAK2 mutant B-ALLs.
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.BBMT.2014.02.011
Abstract: Noninfectious pulmonary syndromes (NIPS) frequently complicate allogeneic stem cell transplantation (allo-SCT). The most common and serious is the bronchiolitis obliterans syndrome, characterized by irreversible fixed airflow obstruction, impaired quality of life, and a high mortality. Treatment for established symptomatic disease is relatively ineffective. We therefore sought to identify potential predictive factors for development of NIPS, which may identify patients at risk in whom earlier intervention may be of benefit. Spirometry and diffusing capacity for carbon monoxide were performed before allo-SCT, day 100, and 1 year after allo-SCT. We retrospectively analyzed spirometry in consecutive patients having allo-SCT from 2004 to 2010, along with computed tomography and bronchoalveolar lavage results to identify cases of NIPS. Cases of bronchiolitis obliterans syndrome were defined as per current National Institutes of Health consensus guidelines. Spirometry results and baseline variables were compared between patients with and without NIPS to identify early predictors and risk factors for NIPS. Of 235 assessable patients, 23 (9.8%) developed NIPS. Median time of onset was day 367 (interquartile range [IQR], 144 to 544 days). Changes in forced expiratory volume in 1 second (ΔFEV1.0) was the best predictor of later NIPS development. Median ΔFEV1.0 from pretransplant to day 100 in patients later developing NIPS was -12% (IQR, -25% to -1%) versus -1% (IQR, -7% to +6%) in unaffected patients, P = .002. From pretransplant to 1 year, ΔFEV1.0 was -19% (IQR, -37% to -6%) versus -3% (IQR, -10% to +4%) in patients later developing NIPS and unaffected patients, respectively, P < .001. Busulfan-based, but not total body irradiation-based, conditioning increased the risk of NIPS (hazard ratio, 9.4 [3.4 to 23.9], P < .001). No cases of NIPS were seen in the 53 patients who received in vivo T cell depletion with antithymocyte globulin (ATG, Genzyme Transplant, Cambridge, MA) (P < .0001). NIPS were associated with high transplant-related mortality relative to unaffected patients (hazard ratio, 6.6 [2.5 to 16.4], P < .001). Spirometry is a potentially useful screening test for identification of presymptomatic NIPS. We recommend 3-monthly spirometry surveillance for up to 2 years post-transplant. Our findings require prospective validation to identify patients in whom earlier intervention may potentially modify the natural history of this disease.
Publisher: Springer Science and Business Media LLC
Date: 12-08-2022
DOI: 10.1038/S41467-022-32485-9
Abstract: CRISPR technologies have advanced cancer modelling in mice, but CRISPR activation (CRISPRa) methods have not been exploited in this context. We establish a CRISPRa mouse ( dCas9a-SAM KI ) for inducing gene expression in vivo and in vitro. Using dCas9a-SAM KI primary lymphocytes, we induce B cell restricted genes in T cells and vice versa, demonstrating the power of this system. There are limited models of aggressive double hit lymphoma. Therefore, we transactivate pro-survival BCL-2 in Eµ-Myc T/+ dCas9a-SAM KI/+ haematopoietic stem and progenitor cells. Mice transplanted with these cells rapidly develop lymphomas expressing high BCL-2 and MYC. Unlike standard Eµ-Myc lymphomas, BCL-2 expressing lymphomas are highly sensitive to the BCL-2 inhibitor venetoclax. We perform genome-wide activation screens in these lymphoma cells and find a dominant role for the BCL-2 protein A1 in venetoclax resistance. Here we show the potential of our CRISPRa model for mimicking disease and providing insights into resistance mechanisms towards targeted therapies.
Publisher: American Society of Hematology
Date: 09-2011
DOI: 10.1182/BLOOD-2011-03-344739
Abstract: Hematopoietic stem cells (HSCs) are rare residents of the bone marrow responsible for the lifelong production of blood cells. Regulation of the balance between HSC self-renewal and differentiation is central to hematopoiesis, allowing precisely regulated generation of mature blood cells at steady state and expanded production at times of rapid need, as well as maintaining ongoing stem cell capacity. Erg, a member of the Ets family of transcription factors, is deregulated in cancers and although Erg is known to be required for regulation of adult HSCs, its precise role has not been defined. We show here that, although heterozygosity for functional Erg is sufficient for adequate steady-state HSC maintenance, Erg+/Mld2 mutant mice exhibit impaired HSC self-renewal after bone marrow transplantation or during recovery from myelotoxic stress. Moreover, although mice functionally compromised for either Erg or Mpl, the receptor for thrombopoietin, a key regulator of HSC quiescence, maintained sufficient HSC activity to sustain hematopoiesis, Mpl−/−Erg+/Mld2 compound mutant mice displayed exacerbated stem cell deficiencies and bone marrow failure. Thus, Erg is a critical regulator of adult HSCs, essential for maintaining self-renewal at times of high HSC cycling.
Publisher: Springer Science and Business Media LLC
Date: 06-04-2022
Publisher: Cold Spring Harbor Laboratory
Date: 03-12-2019
DOI: 10.1101/861542
Abstract: B-cell development is initiated by the stepwise differentiation of hematopoietic stem cells into lineage committed progenitors, ultimately generating the mature B-cells that mediate protective immunity. This highly regulated process also generates clonal immunological ersity via recombination of immunoglobulin genes. While several transcription factors that control B-cell development and V(D)J recombination have been defined, how these processes are initiated and coordinated into a precise regulatory network remains poorly understood. Here, we show that the transcription factor ETS Related Gene ( Erg ) is essential for the earliest steps in B-cell differentiation. Erg initiates a transcriptional network involving the B-cell lineage defining genes, Ebf1 and Pax5 , that directly promotes the expression of key genes involved in V(D)J recombination and formation of the B-cell receptor. Complementation of the Erg-deficiency with a productively rearranged immunoglobulin gene rescued B-cell development, demonstrating that Erg is an essential and exquisitely stage specific regulator of the gene regulatory network controlling B-lymphopoiesis.
Publisher: American Society of Hematology
Date: 24-01-2020
Abstract: Deregulated over-expression of MYC is implicated in the development and malignant progression of most (~70%) human tumors. MYC drives cell growth and proliferation but also, at high levels, promotes apoptosis. Here, we report that the proliferative capacity of MYC-driven normal and neoplastic B lymphoid cells depends on MNT, a MYC-related transcriptional repressor. Our genetic data establish that MNT synergises with MYC by suppressing MYC-driven apoptosis and that it does so primarily by reducing the level of pro-apoptotic BIM. In Em-Myc mice, which model the MYC/IGH chromosome translocation in Burkitt's lymphoma, homozygous Mnt deletion greatly reduced lymphoma incidence by enhancing apoptosis and markedly decreasing premalignant B lymphoid cell populations. Strikingly, by inducing Mnt deletion within transplanted fully-malignant Em-Myc lymphoma cells, we significantly extended transplant recipient survival. The dependency of lymphomas on MNT for survival suggests that drugs inhibiting MNT could significantly boost therapy of MYC-driven tumors by enhancing intrinsic MYC-driven apoptosis.
Publisher: Wiley
Date: 18-10-2021
DOI: 10.1111/IMCB.12505
Abstract: We hypothesize that thrombosis with thrombocytopenia syndrome recently described after administration of adenovirus‐vectored vaccines for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) occurs as a result of the unique properties of the adenovirus vectors, which can have widespread biodistribution throughout the body. The antigen is delivered to megakaryocyte cells, which act as part of the primary immune system and distribute the antigen within progeny platelets, also a key component of the immune system. The interaction of the antigen induces preformed antiplatelet factor 4 (PF4) antibodies to bind to PF4–heparan sulfate complexes in the absence of exogenous heparin, at sites where the heparan sulfate concentration in the vascular glycocalyx is optimal for complex formation, causing thrombosis and thrombocytopenia as observed clinically. This hypothesis is testable in cell culture and animal models, and potentially in vivo , and if proven correct has significant implications for vaccine development and our understanding of the links between the coagulation and immune systems.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2020
DOI: 10.1038/S41590-020-0799-X
Abstract: A classical view of blood cell development is that multipotent hematopoietic stem and progenitor cells (HSPCs) become lineage-restricted at defined stages. Lin
Publisher: Springer Science and Business Media LLC
Date: 15-06-2020
DOI: 10.1038/S41467-020-16828-Y
Abstract: B lymphoid development is initiated by the differentiation of hematopoietic stem cells into lineage committed progenitors, ultimately generating mature B cells. This highly regulated process generates clonal immunological ersity via recombination of immunoglobulin V, D and J gene segments. While several transcription factors that control B cell development and V(D)J recombination have been defined, how these processes are initiated and coordinated into a precise regulatory network remains poorly understood. Here, we show that the transcription factor ETS Related Gene ( Erg ) is essential for early B lymphoid differentiation. Erg initiates a transcriptional network involving the B cell lineage defining genes, Ebf1 and Pax5 , which directly promotes expression of key genes involved in V(D)J recombination and formation of the B cell receptor. Complementation of Erg deficiency with a productively rearranged immunoglobulin gene rescued B lineage development, demonstrating that Erg is an essential and stage-specific regulator of the gene regulatory network controlling B lymphopoiesis.
Publisher: Proceedings of the National Academy of Sciences
Date: 07-04-2014
Abstract: Blood platelets, the small circulating cells that coordinate hemostasis, are produced by specialized bone marrow cells called megakaryocytes. The cytokine thrombopoietin (TPO) is a key regulator of platelet production acting via its specific cell receptor, Mpl. Via genetic modification of the Mpl allele in mice, we precisely define the bone marrow cells that express Mpl and, by genetically removing Mpl from megakaryocytes and platelets, we show TPO signaling via Mpl is not required in megakaryocytes for their expansion, maturation, or platelet production. Rather, Mpl expression on megakaryocytes is essential for regulating TPO availability in the bone marrow microenvironment to prevent myeloproliferation, a model we suggest is important for human disease.
Publisher: Elsevier BV
Date: 07-2008
Publisher: Proceedings of the National Academy of Sciences
Date: 10-11-2009
Abstract: Two distinct bone marrow-derived blast colony-forming cells can generate colonies of lineage-restricted progenitor cells in agar cultures of murine bone marrow. Both cell types selectively had a Kit + ScaI + phenotype distinguishing them from most lineage-restricted progenitor cells. Multicentric blast colony-forming cells stimulated by stem cell factor plus interleukin-6 (IL-6) (BL-CFC-S) were separable from most dispersed blast colony-forming cells stimulated by Flt3 ligand and IL-6 (BL-CFC-F) using CD34 and Flt3R probes. Multicentric BL-CFC-S cofractionated with colony-forming units, spleen (CFU-S) supporting the possibility that the 2 cells may be identical. The colony populations generated by BL-CFC-S were similar in their phenotype and proliferative capacity to progenitor cells in whole bone marrow but the progeny of BL-CFC-F were skewed with an abnormally high proportion of Kit − Flt3R + cells whose clonogenic cells tended to generate only macrophage progeny. Both blast colony populations had a high percentage of GR1 + and Mac1 + cells but BL-CFC-F colonies also contained a significant population of B220 + and IL-7R + cells relevant to the superior ability of BL-CFC-F colony cells to generate B lymphocytes and the known dependency of this process on Flt3 ligand and IL-7. The commitment events and phenotypic changes during the generation of differing progenitor cells in blast colonies can now be clonally analyzed in a convenient in vitro culture system.
Publisher: American Society of Hematology
Date: 26-10-2023
Publisher: American Society of Hematology
Date: 22-06-2020
DOI: 10.1182/BLOODADVANCES.2019001416
Abstract: Improving survival outcomes in adult B-cell acute lymphoblastic leukemia (B-ALL) remains a clinical challenge. Relapsed disease has a poor prognosis despite the use of tyrosine kinase inhibitors (TKIs) for Philadelphia chromosome positive (Ph+ ALL) cases and immunotherapeutic approaches, including blinatumomab and chimeric antigen receptor T cells. Targeting aberrant cell survival pathways with selective small molecule BH3-mimetic inhibitors of BCL-2 (venetoclax, S55746), BCL-XL (A1331852), or MCL1 (S63845) is an emerging therapeutic option. We report that combined targeting of BCL-2 and MCL1 is synergistic in B-ALL in vitro. The combination demonstrated greater efficacy than standard chemotherapeutics and TKIs in primary s les from adult B-ALL with Ph+ ALL, Ph-like ALL, and other B-ALL. Moreover, combined BCL-2 or MCL1 inhibition with dasatinib showed potent killing in primary Ph+ B-ALL cases, but the BH3-mimetic combination appeared superior in vitro in a variety of Ph-like ALL s les. In PDX models, combined BCL-2 and MCL1 targeting eradicated ALL from Ph− and Ph+ B-ALL cases, although fatal tumor lysis was observed in some instances of high tumor burden. We conclude that a dual BH3-mimetic approach is highly effective in erse models of high-risk human B-ALL and warrants assessment in clinical trials that incorporate tumor lysis precautions.
Publisher: Hindawi Limited
Date: 2013
DOI: 10.1155/2013/164501
Abstract: The diagnosis of acute promyelocytic leukaemia (APL) is usually confirmed by cytogenetics showing the characteristic t(15 ), but a minority of patients have a masked PML/RARA fusion. We report ten patients with APL and no evidence of the t(15 ), in whom the insertion of RARA into PML could not be demonstrated by initial FISH studies using a standard dual fusion probe but was readily identified using smaller probes. Given the need for rapid diagnosis of APL, it is important to be aware of the false negative rate for large PML/RARA FISH probes in the setting of masked rearrangements.
Location: Australia
Start Date: 2017
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2017
End Date: 2019
Funder: National Health and Medical Research Council
View Funded Activity