Publications by authors named "Emir Hadzijusufovic"

38 Publications

Clinical Impact of Skin Lesions in Mastocytosis: A Multicenter Study of the European Competence Network on Mastocytosis.

J Invest Dermatol 2021 Feb 11. Epub 2021 Feb 11.

Department of Internal Medicine IV, Oncology, Hematology, Hemostaseology, University Halle (Saale), Halle (Saale), Germany.

Mastocytosis is a rare neoplasm characterized by the expansion and accumulation of mast cells in various organ systems. Systemic mastocytosis (SM) may or may not present with cutaneous lesions. To examine the frequency and clinical impact of cutaneous involvement, data on 1,510 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis were analyzed. Cutaneous involvement was found in 1,195 of 1,510 patients (79.1%). Of these, 286 had cutaneous mastocytosis, and 721 had SM with skin involvement. Adult patients with skin involvement who did not have a bone marrow examination (n = 188) were defined as having mastocytosis in the skin. In 315 patients, SM without skin involvement was found. The percentage of cases with cutaneous involvement was higher in indolent SM (100%) and smoldering SM (87.9%) compared to aggressive SM (46.8%) or mast cell leukemia (38.5%). After a median follow-up of 5.6 years, no patient with cutaneous mastocytosis had died, but 2.6% of the patients with mastocytosis in the skin, 5.7% of the patients with SM with skin involvement, and 28.95% of the patients with SM without skin involvement had died. Overall survival was longer in patients with skin involvement (cutaneous mastocytosis and/or mastocytosis in the skin and/or SM with skin involvement) than in patients with SM without skin involvement (P < 0.0001). These data argue for a thorough examination of both the skin and bone marrow in adult patients with mastocytosis.
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http://dx.doi.org/10.1016/j.jid.2020.12.030DOI Listing
February 2021

Scoring the Risk of Having Systemic Mastocytosis in Adult Patients with Mastocytosis in the Skin.

J Allergy Clin Immunol Pract 2021 Apr 23;9(4):1705-1712.e4. Epub 2020 Dec 23.

Division of Allergy and Clinical Immunology, Department of Medicine, University of Salerno, Salerno, Italy.

Background: Mastocytosis in adults often presents with skin lesions. A bone marrow biopsy is necessary to confirm or exclude the presence of systemic mastocytosis (SM) in these cases. When a bone marrow biopsy is not performed, the provisional diagnosis is mastocytosis in the skin (MIS). No generally accepted scoring system has been established to estimate the risk of SM in these patients.

Objective: To develop a risk score to predict SM in adults with MIS.

Methods: We examined 1145 patients with MIS from the European Competence Network on Mastocytosis Registry who underwent a bone marrow biopsy. A total of 944 patients had SM and 201 patients had cutaneous mastocytosis; 63.7% were female, and 36.3% were male. Median age was 44 ± 13.3 years. The median serum tryptase level amounted to 29.3 ± 81.9 ng/mL. We established a multivariate regression model using the whole population of patients as a training and validation set (bootstrapping). A risk score was developed and validated with receiver-operating curves.

Results: In the multivariate model, the tryptase level (P < .001), constitutional/cardiovascular symptoms (P = .014), and bone symptoms/osteoporosis (P < .001) were independent predictors of SM (P < .001; sensitivity, 90.7%; specificity, 69.1%). A 6-point risk score was established (risk, 10.7%-98.0%) and validated.

Conclusions: Using a large data set of the European Competence Network on Mastocytosis Registry, we created a risk score to predict the presence of SM in patients with MIS. Although the score will need further validation in independent cohorts, our score seems to discriminate safely between patients with SM and with pure cutaneous mastocytosis.
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http://dx.doi.org/10.1016/j.jaip.2020.12.022DOI Listing
April 2021

Mast cells as a unique hematopoietic lineage and cell system: From Paul Ehrlich's visions to precision medicine concepts.

Theranostics 2020 29;10(23):10743-10768. Epub 2020 Aug 29.

Departments of Pathology and of Microbiology and Immunology, and the Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, USA.

The origin and functions of mast cells (MCs) have been debated since their description by Paul Ehrlich in 1879. MCs have long been considered 'reactive bystanders' and 'amplifiers' in inflammatory processes, allergic reactions, and host responses to infectious diseases. However, knowledge about the origin, phenotypes and functions of MCs has increased substantially over the past 50 years. MCs are now known to be derived from multipotent hematopoietic progenitors, which, through a process of differentiation and maturation, form a unique hematopoietic lineage residing in multiple organs. In particular, MCs are distinguishable from basophils and other hematopoietic cells by their unique phenotype, origin(s), and spectrum of functions, both in innate and adaptive immune responses and in other settings. The concept of a unique MC lineage is further supported by the development of a distinct group of neoplasms, collectively referred to as mastocytosis, in which MC precursors expand as clonal cells. The clinical consequences of the expansion and/or activation of MCs are best established in mastocytosis and in allergic inflammation. However, MCs have also been implicated as important participants in a number of additional pathologic conditions and physiological processes. In this article, we review concepts regarding MC development, factors controlling MC expansion and activation, and some of the fundamental roles MCs may play in both health and disease. We also discuss new concepts for suppressing MC expansion and/or activation using molecularly-targeted drugs.
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http://dx.doi.org/10.7150/thno.46719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7482799PMC
August 2020

In vitro effects of histamine receptor 1 antagonists on proliferation and histamine release in canine neoplastic mast cells.

Vet Med Sci 2021 01 13;7(1):57-68. Epub 2020 Sep 13.

Division of Hematology & Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria.

Canine mastocytomas (MCTs) are characterized by rapid proliferation of neoplastic mast cells (MCs) and clinical signs caused by MC-derived mediators. In dogs suffering from MCT, histamine receptor 1 (HR1) antagonists are frequently used to control mediator-related clinical symptoms. Previous studies have shown that the HR1 antagonists loratadine and terfenadine exert some growth-inhibitory effects on neoplastic MCs. We examined whether other HR1 antagonists used in clinical practice (desloratadine, rupatadine, cyproheptadine, dimetindene, diphenhydramine) affect proliferation and survival of neoplastic MCs. Furthermore, we analysed whether these HR1 antagonists counteract IgE-dependent histamine release from a MC line harbouring a functional IgE-receptor. HR1 antagonists were applied on two canine MC lines, C2 and NI-1, and on primary MCs obtained from three MCT samples. The HR1 antagonists desloratadine, rupatadine and cyproheptadine were found to be more potent in decreasing proliferation of C2 and NI-1 cells when compared with dimetindene and diphenhydramine. Similar effects were seen in primary neoplastic MCs, except for diphenhydramine, which exerted more potent growth-inhibitory effects than the other HR1 antagonists. Drug-induced growth-inhibition in C2 and NI-1 cells was accompanied by apoptosis. Loratadine, desloratadine and rupatadine also suppressed IgE-dependent histamine release in NI-1 cells. However, drug concentrations required to elicit substantial effects on growth or histamine release were relatively high (>10 µM). Therefore, it remains unknown whether these drugs or similar, more potent, HR1-targeting drugs can suppress growth or activation of canine neoplastic MCs in vivo.
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http://dx.doi.org/10.1002/vms3.336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840218PMC
January 2021

Hereditary α tryptasemia is a valid genetic biomarker for severe mediator-related symptoms in mastocytosis.

Blood 2021 01;137(2):238-247

Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.

Mastocytosis is a hematopoietic neoplasm characterized by expansion of KIT D816V-mutated clonal mast cells in various organs and severe or even life-threatening anaphylactic reactions. Recently, hereditary α-tryptasemia (HαT) has been described as a common genetic trait with increased copy numbers of the α-tryptase encoding gene, TPSAB1, and associated with an increased basal serum tryptase level and a risk of mast cell activation. The purpose of our study was to elucidate the clinical relevance of HαT in patients with mastocytosis. TPSAB1 germline copy number variants were assessed by digital polymerase chain reaction in 180 mastocytosis patients, 180 sex-matched control subjects, 720 patients with other myeloid neoplasms, and 61 additional mastocytosis patients of an independent validation cohort. α-Tryptase encoding TPSAB1 copy number gains, compatible with HαT, were identified in 17.2% of mastocytosis patients and 4.4% of the control population (P < .001). Patients with HαT exhibited higher tryptase levels than patients without HαT (median tryptase in HαT+ cases: 49.6 ng/mL vs HαT- cases: 34.5 ng/mL, P = .004) independent of the mast cell burden. Hymenoptera venom hypersensitivity reactions and severe cardiovascular mediator-related symptoms/anaphylaxis were by far more frequently observed in mastocytosis patients with HαT than in those without HαT. Results were confirmed in an independent validation cohort. The high prevalence of HαT in mastocytosis hints at a potential pathogenic role of germline α-tryptase encoding TPSAB1 copy number gains in disease evolution. Together, our data suggest that HαT is a novel emerging robust biomarker in mastocytosis that is useful for determining the individual patient´s risk of developing severe anaphylaxis.
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http://dx.doi.org/10.1182/blood.2020006157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116780PMC
January 2021

STAT5 is Expressed in CD34/CD38 Stem Cells and Serves as a Potential Molecular Target in Ph-Negative Myeloproliferative Neoplasms.

Cancers (Basel) 2020 Apr 21;12(4). Epub 2020 Apr 21.

Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090 Vienna, Austria.

Janus kinase 2 (JAK2) and signal transducer and activator of transcription-5 (STAT5) play a key role in the pathogenesis of myeloproliferative neoplasms (MPN). In most patients, V617F or mutations are found and lead to activation of various downstream signaling cascades and molecules, including STAT5. We examined the presence and distribution of phosphorylated (p) STAT5 in neoplastic cells in patients with MPN, including polycythemia vera (PV, = 10), essential thrombocythemia (ET, = 15) and primary myelofibrosis (PMF, = 9), and in the V617F-positive cell lines HEL and SET-2. As assessed by immunohistochemistry, MPN cells displayed pSTAT5 in all patients examined. Phosphorylated STAT5 was also detected in putative CD34/CD38 MPN stem cells (MPN-SC) by flow cytometry. Immunostaining experiments and Western blotting demonstrated pSTAT5 expression in both the cytoplasmic and nuclear compartment of MPN cells. Confirming previous studies, we also found that JAK2-targeting drugs counteract the expression of pSTAT5 and growth in HEL and SET-2 cells. Growth-inhibition of MPN cells was also induced by the STAT5-targeting drugs piceatannol, pimozide, AC-3-019 and AC-4-130. Together, we show that CD34/CD38 MPN-SC express pSTAT5 and that pSTAT5 is expressed in the nuclear and cytoplasmic compartment of MPN cells. Whether direct targeting of pSTAT5 in MPN-SC is efficacious in MPN patients remains unknown.
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http://dx.doi.org/10.3390/cancers12041021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225958PMC
April 2020

International prognostic scoring system for mastocytosis (IPSM): a retrospective cohort study.

Lancet Haematol 2019 Dec 31;6(12):e638-e649. Epub 2019 Oct 31.

Department of Oncology, Haematology, Haemostaseology and Stem Cell Transplantation, University Hospital RWTH Aachen, Aachen, Germany.

Background: The WHO classification separates mastocytosis into distinct variants, but prognostication remains a clinical challenge. The aim of this study was to improve prognostication for patients with mastocytosis.

Methods: We analysed data of the registry of the European Competence Network on Mastocytosis including 1639 patients (age 17-90 years) diagnosed with mastocytosis according to WHO criteria between Jan 12, 1978, and March 16, 2017. Univariate and multivariate analyses with Cox regression were applied to identify prognostic variables predicting survival outcomes and to establish a prognostic score. We validated this International Prognostic Scoring System in Mastocytosis (IPSM) with data of 462 patients (age 17-79 years) from the Spanish network Red Española de Mastocitosis diagnosed between Jan 22, 1998, and Nov 2, 2017.

Findings: The prognostic value of the WHO classification was confirmed in our study (p<0·0001). For patients with non-advanced mastocytosis (n=1380), we identified age 60 years or older (HR 10·75, 95% CI 5·68-20·32) and a concentration of alkaline phosphatase 100 U/L or higher (2·91, 1·60-5·30) as additional independent prognostic variables for overall survival. The resulting scoring system divided patients with non-advanced mastocytosis into three groups: low (no risk factors), intermediate 1 (one risk factor), and intermediate 2 (two risk factors). Overall survival and progression-free survival differed significantly among these groups (p<0·0001). In patients with advanced mastocytosis (n=259), age 60 years or older (HR 2·14, 95% CI 1·42-3·22), a concentration of tryptase 125 ng/mL or higher (1·81, 1·20-2·75), a leukocyte count of 16 × 10 per L or higher (1·88, 1·27-2·79), haemoglobin of 11 g/dL or lower (1·71, 1·13-2·57), a platelet count of 100 × 10 per L or lower (1·63, 1·13-2·34), and skin involvement (0·46, 0·30-0·69) were prognostic variables. Based on these variables, a separate score for advanced mastocytosis with four risk categories was established, with significantly different outcomes for overall survival and progression-free survival (p<0·0001). The prognostic value of both scores was confirmed in 413 patients with non-advanced disease and 49 with advanced mastocytosis from the validation cohort.

Interpretation: The IPSM scores for patients with non-advanced and advanced mastocytosis can be used to predict survival outcomes and guide treatment decisions. However, the predictive value of the IPSM needs to be confirmed in forthcoming trials.

Funding: Austrian Science Fund, Deutsche Forschungsgemeinschaft, Koeln Fortune Program, Charles and Ann Johnson Foundation, Instituto de Salud Carlos III, Fondos FEDER, Research-Foundation Flanders/Fonds Wetenschappelijk Onderzoek, Clinical Research-Fund of the University Hospitals Leuven, and Research-Foundation Flanders/Fonds Wetenschappelijk Onderzoek.
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http://dx.doi.org/10.1016/S2352-3026(19)30166-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115823PMC
December 2019

Effects of ibrutinib on proliferation and histamine release in canine neoplastic mast cells.

Vet Comp Oncol 2019 Dec 13;17(4):553-561. Epub 2019 Aug 13.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Vienna, Austria.

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib is effective in the treatment of human chronic lymphocytic leukaemia and mantle cell lymphoma. Recent data have shown that ibrutinib also blocks IgE-dependent activation and histamine release in human basophils (BAs) and mast cells (MCs). The aim of this study was to investigate whether BTK serves as a novel therapeutic target in canine mast cell tumours (MCTs). We evaluated the effects of ibrutinib on two canine MC lines, C2 and NI-1 and on primary MCs obtained from canine MCTs (n = 3). Using flow cytometry, we found that ibrutinib suppresses phosphorylation of BTK and of downstream STAT5 in both MC lines. In addition, ibrutinib decreased proliferation of neoplastic MCs, with IC values ranging between 0.1 and 1 μM in primary MCT cells and between 1 and 3 μM in C2 and NI-1 cells. In C2 cells, the combination "ibrutinib + midostaurin" produced synergistic growth-inhibitory effects. At higher concentrations, ibrutinib also induced apoptosis in both MC lines. Finally, ibrutinib was found to suppress IgE-dependent histamine release in primary MCT cells, with IC values ranging from 0.05 to 0.1 μM in NI-1 cells, and from 0.05 to 1 μM in primary MCT cells. In summary, ibrutinib exerts anti-proliferative effects in canine neoplastic MCs and counteracts IgE-dependent histamine release in these cells. Based on our data, ibrutinib may be considered as a novel therapeutic agent for the treatment of canine MCT. The value of BTK inhibition in canine MCT patients remains to be elucidated in clinical trials.
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http://dx.doi.org/10.1111/vco.12520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6900099PMC
December 2019

A kinase profile-adapted drug combination elicits synergistic cooperative effects on leukemic cells carrying BCR-ABL1 in Ph+ CML.

Leuk Res 2019 03 28;78:36-44. Epub 2018 Dec 28.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Austria; Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, Austria. Electronic address:

In chronic myeloid leukemia (CML), resistance against second-generation tyrosine kinase inhibitors (TKI) remains a serious clinical challenge, especially in the context of multi-resistant BCR-ABL1 mutants, such as T315I. Treatment with ponatinib may suppress most of these mutants, including T315I, but is also associated with a high risk of clinically relevant side effects. We screened for alternative treatment options employing available tyrosine kinase inhibitors (TKI) in combination. Dasatinib and bosutinib are two second-generation TKI that bind to different, albeit partially overlapping, spectra of kinase targets in CML cells. This observation prompted us to explore anti-leukemic effects of the combination dasatinib + bosutinib in highly resistant primary CML cells, various CML cell lines (K562, K562R, KU812, KCL22) and Ba/F3 cells harboring various BCR-ABL1 mutant-forms. We found that bosutinib synergizes with dasatinib in inducing growth inhibition and apoptosis in all CML cell lines and in Ba/F3 cells exhibiting BCR-ABL1. Clear synergistic effects were also observed in primary CML cells in all patients tested (n = 20), including drug-resistant cells carrying BCR-ABL1. Moreover, the drug combination produced cooperative or even synergistic apoptosis-inducing effects on CD34/CD38 CML stem cells. Finally, we found that the drug combination is a potent approach to block the activity of major additional CML targets, including LYN, KIT and PDGFRα. Together, bosutinib and dasatinib synergize in producing anti-leukemic effects in drug-resistant CML cells. Whether such cooperative TKI effects also occur in vivo in patients with drug-resistant CML, remains to be determined in forthcoming studies.
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http://dx.doi.org/10.1016/j.leukres.2018.12.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834439PMC
March 2019

The Data Registry of the European Competence Network on Mastocytosis (ECNM): Set Up, Projects, and Perspectives.

J Allergy Clin Immunol Pract 2019 01 8;7(1):81-87. Epub 2018 Nov 8.

Division of Hematology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.

Mastocytosis is a unique hematologic neoplasm with complex biology and pathology and a variable clinical course. The disease can essentially be divided into cutaneous mastocytosis (CM) and systemic mastocytosis (SM). In adults, SM is diagnosed in most cases and manifests as either indolent or advanced disease. Patients with advanced SM have an unfavorable prognosis with reduced survival. However, so far, little is known about the prevalence of various categories of SM and about prognostic factors. In an attempt to learn more about the behavior and evolution of various forms of CM and SM, the European Competence Network on Mastocytosis (ECNM) initiated a mastocytosis registry in 2012. In this article, the set up and start phase of this registry are described. Until 2018, more than 3000 patients from 12 countries and 25 centers have been enrolled. In a majority of all patients, robust follow-up data and relevant clinical end points are available. Using this data set, a series of registry projects have been launched, with the aim to validate previously identified diagnostic and prognostic variables and to identify new disease-related and patient-related parameters in various forms of mastocytosis. Moreover, the core data set of the registry will be useful to establish multiparametric scoring systems through which prognostication and individualized management of patients with mastocytosis should improve in the foreseeable future.
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http://dx.doi.org/10.1016/j.jaip.2018.09.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115815PMC
January 2019

Comparative oncology: The paradigmatic example of canine and human mast cell neoplasms.

Vet Comp Oncol 2019 Mar 24;17(1):1-10. Epub 2018 Sep 24.

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Vienna, Austria.

In humans, advanced mast cell (MC) neoplasms are rare malignancies with a poor prognosis. Only a few preclinical models are available, and current treatment options are limited. In dogs, MC neoplasms are the most frequent malignant skin tumours. Unlike low-grade MC neoplasms, high-grade MC disorders usually have a poor prognosis with short survival. In both species, neoplastic MCs display activating KIT mutations, which are considered to contribute to disease evolution. Therefore, tyrosine kinase inhibitors against KIT have been developed. Unfortunately, clinical responses are unpredictable and often transient, which remains a clinical challenge in both species. Therefore, current efforts focus on the development of new improved treatment strategies. The field of comparative oncology may assist in these efforts and accelerate human and canine research regarding diagnosis, prognostication, and novel therapies. In this article, we review the current status of comparative oncology approaches and perspectives in the field of MC neoplasms.
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http://dx.doi.org/10.1111/vco.12440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6378619PMC
March 2019

Ludwig Boltzmann Cluster Oncology (LBC ONC): first 10 years and future perspectives.

Wien Klin Wochenschr 2018 Sep 13;130(17-18):517-529. Epub 2018 Jul 13.

Ludwig Boltzmann Cluster Oncology, Vienna, Austria.

In 2008 the Ludwig Boltzmann Cluster Oncology (LBC ONC) was established on the basis of two previous Ludwig Boltzmann Institutes working in the field of hematology and cancer research. The general aim of the LBC ONC is to improve treatment of hematopoietic neoplasms by eradicating cancer-initiating and disease-propagating cells, also known as leukemic stem cells (LSC) in the context of leukemia. In a first phase, the LBC ONC characterized the phenotype and molecular aberration profiles of LSC in various malignancies. The LSC phenotypes were established in acute and chronic myeloid leukemia, in acute lymphoblastic leukemia and in chronic lymphocytic leukemia. In addition, the concept of preleukemic (premalignant) neoplastic stem cells (pre-L-NSC) was coined by the LBC ONC and was tested in myelodysplastic syndromes and myeloproliferative neoplasms. Phenotypic characterization of LSC provided a solid basis for their purification and for the characterization of specific target expression profiles. In a second phase, molecular markers and targets were validated. This second phase is ongoing and should result in the development of new diagnostics parameters and novel, more effective, LSC-eradicating, treatment strategies; however, many issues still remain to be solved, such as sub-clonal evolution, LSC niche interactions, immunologic control of LSC, and LSC resistance. In the forthcoming years, the LBC ONC will concentrate on developing LSC-eradicating strategies, with special focus on LSC resistance, precision medicine and translation of LSC-eradicating concepts into clinical application.
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http://dx.doi.org/10.1007/s00508-018-1355-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132878PMC
September 2018

The KIT and PDGFRA switch-control inhibitor DCC-2618 blocks growth and survival of multiple neoplastic cell types in advanced mastocytosis.

Haematologica 2018 05 8;103(5):799-809. Epub 2018 Feb 8.

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Austria

Systemic mastocytosis is a complex disease defined by abnormal growth and accumulation of neoplastic mast cells in various organs. Most patients exhibit a D816V-mutated variant of , which confers resistance against imatinib. Clinical problems in systemic mastocytosis arise from mediator-related symptoms and/or organ destruction caused by malignant expansion of neoplastic mast cells and/or other myeloid cells in various organ systems. DCC-2618 is a spectrum-selective pan KIT and PDGFRA inhibitor which blocks KIT D816V and multiple other kinase targets relevant to systemic mastocytosis. We found that DCC-2618 inhibits the proliferation and survival of various human mast cell lines (HMC-1, ROSA, MCPV-1) as well as primary neoplastic mast cells obtained from patients with advanced systemic mastocytosis (IC <1 μM). Moreover, DCC-2618 decreased growth and survival of primary neoplastic eosinophils obtained from patients with systemic mastocytosis or eosinophilic leukemia, leukemic monocytes obtained from patients with chronic myelomonocytic leukemia with or without concomitant systemic mastocytosis, and blast cells obtained from patients with acute myeloid leukemia. Furthermore, DCC-2618 was found to suppress the proliferation of endothelial cells, suggesting additional drug effects on systemic mastocytosis-related angiogenesis. Finally, DCC-2618 was found to downregulate IgE-mediated histamine release from basophils and tryptase release from mast cells. Together, DCC-2618 inhibits growth, survival and activation of multiple cell types relevant to advanced systemic mastocytosis. Whether DCC-2618 is effective in patients with advanced systemic mastocytosis is currently under investigation in clinical trials.
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http://dx.doi.org/10.3324/haematol.2017.179895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5927976PMC
May 2018

Evaluation of cooperative antileukemic effects of nilotinib and vildagliptin in Ph chronic myeloid leukemia.

Exp Hematol 2018 01 12;57:50-59.e6. Epub 2017 Oct 12.

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Vienna, Austria; Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria.

Chronic myeloid leukemia (CML) is a stem cell (SC) neoplasm characterized by the BCR/ABL1 oncogene. Although the disease can be kept under control using BCR/ABL1 tyrosine kinase inhibitors (TKIs) in most cases, some patients relapse or have resistant disease, so there is a need to identify new therapeutic targets in this malignancy. Recent data suggest that leukemic SCs (LSCs) in CML display the stem-cell (SC)-mobilizing cell surface enzyme dipeptidyl-peptidase IV (DPPIV = CD26) in an aberrant manner. In the present study, we analyzed the effects of the DPPIV blocker vildagliptin as single agent or in combination with the BCR/ABL1 TKI imatinib or nilotinib on growth and survival of CML LSCs in vitro and on LSC engraftment in an in vivo xenotransplantation nonobese diabetic SCID-IL-2Rγ (NSG) mouse model. We found that nilotinib induces apoptosis in CML LSCs and inhibits their engraftment in NSG mice. In contrast, no substantial effects were seen with imatinib or vildagliptin. Nevertheless, vildagliptin was found to reduce the "mobilization" of CML LSCs from a stroma cell layer consisting of mouse fibroblasts in an in vitro co-culture model, suggesting reduced disease expansion. However, although vildagliptin and nilotinib produced cooperative effects in individual experiments, overall, no significant effects of coadministered vildagliptin over nilotinib or imatinib treatment alone were seen on the engraftment of CML cells in NSG mice. Gliptins may be interesting drugs in the context of CML and nilotinib therapy, but our preclinical studies did not reveal a major cooperative effect of the drug-combination vildagliptin + nilotinib on engraftment of CML cells in NSG mice.
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http://dx.doi.org/10.1016/j.exphem.2017.09.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115814PMC
January 2018

Risk factors and mechanisms contributing to TKI-induced vascular events in patients with CML.

Leuk Res 2017 08 12;59:47-54. Epub 2017 May 12.

Medical Clinic III for Oncology, Haematology, Immunology and Rheumatology, University Hospital Bonn (UKB), Germany.

Vascular adverse events (VAE) are an emerging problem in patients with chronic myeloid leukemia (CML) receiving second-generation BCR-ABL1 tyrosine kinase inhibitors (TKI). Relevant VAE comprise peripheral, cerebral, and coronary artery changes in patients receiving nilotinib, venous and arterial occlusive events during ponatinib therapy, and pulmonary hypertension in patients receiving dasatinib. Although each TKI binds to a unique profile of molecular targets in leukemic cells and vascular cells, the exact etiology of drug-induced vasculopathies remains uncertain. Recent data suggest that predisposing molecular factors, pre-existing cardiovascular risk factors as well as certain comorbidities contribute to the etiology of VAE in these patients. In addition, direct effects of these TKI on vascular endothelial cells have been demonstrated and are considered to contribute essentially to VAE evolution. In the current article, we discuss mechanisms underlying the occurrence of VAE in TKI-treated patients with CML, with special emphasis on vascular and perivascular target cells and involved molecular (vascular) targets of VAE-triggering TKI. In addition, we discuss optimal patient selection and drug selection through which the risk of occurrence of cardiovascular events can hopefully be minimized while maintaining optimal anti-leukemic effects in CML, thereby following the principles of personalized medicine.
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http://dx.doi.org/10.1016/j.leukres.2017.05.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115818PMC
August 2017

TKI rotation-induced persistent deep molecular response in multi-resistant blast crisis of Ph+ CML.

Oncotarget 2017 Apr;8(14):23061-23072

Department of Laboratory Medicine, Medical University of Vienna, Austria.

In chronic myeloid leukemia (CML) resistance against one or more BCR-ABL1 tyrosine kinase inhibitors (TKI) remains a clinical challenge. Preclinical data suggest that TKI combinations may overcome resistance. We report on a heavily pre-treated 78 year-old female patient with CML who developed multi-resistant blast crisis with bone marrow fibrosis and a Ph- clone. Treatment with ponatinib resulted in blast cell clearance, decrease in fibrosis, and disappearance of BCR-ABL1, but also in severe thrombocytopenia with bleedings requiring platelet transfusions. We therefore switched from ponatinib to bosutinib. During bosutinib, platelet counts recovered. However, after 6 months, BCR-ABL1 mRNA levels increased to > 1%. Therefore, we ´switched back´ to ponatinib, and this was again followed by disappearance of BCR-ABL1 and a decrease in platelets. During the next 2 years, we applied ponatinib and bosutinib in continuous rotation-cycles and added hydroxyurea in order to suppress all sub-clones and to balance between efficacy and potential side effects following the principle of personalized medicine. With this approach the patient remained in complete molecular response and reached normal blood counts and a normal quality of life without vascular or other side effects. In conclusion, TKI rotation is a novel potent approach to suppress multiple resistant sub-clones and to balance between clinical efficacy and side effects in patients with advanced CML. Clinical trials are now warranted to show that TKI-rotation is in general safe and effective in these patients.
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http://dx.doi.org/10.18632/oncotarget.15481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5410285PMC
April 2017

The JAK2/STAT5 signaling pathway as a potential therapeutic target in canine mastocytoma.

Vet Comp Oncol 2018 Mar 11;16(1):55-68. Epub 2017 Apr 11.

Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria.

Background: Mastocytoma are frequently diagnosed cutaneous neoplasms in dogs. In non-resectable mastocytoma patients, novel targeted drugs are often applied. The transcription factor STAT5 has been implicated in the survival of human neoplastic mast cells (MC). Our study evaluated the JAK2/STAT5 pathway as a novel target in canine mastocytoma.

Materials And Methods: We employed inhibitors of JAK2 (R763, TG101348, AZD1480, ruxolitinib) and STAT5 (pimozide, piceatannol) and evaluated their effects on 2 mastocytoma cell lines, C2 and NI-1.

Results: Activated JAK2 and STAT5 were detected in both cell lines. The drugs applied were found to inhibit proliferation and survival in these cells with the following rank-order of potency: R763 > TG101348 > AZD1480 > pimozide > ruxolitinib > piceatannol. Moreover, synergistic anti-neoplastic effects were obtained by combining pimozide with KIT-targeting drugs (toceranib, masitinib, nilotinib, midostaurin) in NI-1 cells.

Conclusion: The JAK2/STAT5 pathway is a novel potential target of therapy in canine mastocytoma.
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http://dx.doi.org/10.1111/vco.12311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5824979PMC
March 2018

Identification of the Ki-1 antigen (CD30) as a novel therapeutic target in systemic mastocytosis.

Blood 2015 Dec 20;126(26):2832-41. Epub 2015 Oct 20.

Department of Internal Medicine I, Division of Hematology and Hemostaseology and Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Vienna, Austria;

The Ki-1 antigen (CD30) is an established therapeutic target in patients with Hodgkin lymphoma and anaplastic large-cell lymphoma. We have recently shown that CD30 is expressed abundantly in the cytoplasm of neoplastic mast cells (MCs) in patients with advanced systemic mastocytosis (SM). In the current study, we asked whether CD30 is expressed on the surface of neoplastic MCs in advanced SM, and whether this surface structure may serve as therapeutic target in SM. As assessed by flow cytometry, CD30 was found to be expressed on the surface of neoplastic MCs in 3 of 25 patients (12%) with indolent SM, 4 of 7 patients (57%) with aggressive SM, and 4 of 7 patients (57%) with MC leukemia. The immature RAS-transformed human MC line MCPV-1.1 also expressed cell surface CD30, whereas the KIT-transformed MC line HMC-1.2 expressed no detectable CD30. The CD30-targeting antibody-conjugate brentuximab-vedotin inhibited proliferation in neoplastic MCs, with lower IC50 values obtained in CD30(+) MCPV-1.1 cells (10 µg/mL) compared with CD30(-) HMC-1.2 cells (>50 µg/mL). In addition, brentuximab-vedotin suppressed the engraftment of MCPV-1.1 cells in NSG mice. Moreover, brentuximab-vedotin produced apoptosis in all CD30(+) MC lines tested as well as in primary neoplastic MCs in patients with CD30(+) SM, but did not induce apoptosis in neoplastic MCs in patients with CD30(-) SM. Furthermore, brentuximab-vedotin was found to downregulate anti-IgE-induced histamine release in CD30(+) MCs. Finally, brentuximab-vedotin and the KIT D816V-targeting drug PKC412 produced synergistic growth-inhibitory effects in MCPV-1.1 cells. Together, CD30 is a promising new drug target for patients with CD30(+) advanced SM.
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http://dx.doi.org/10.1182/blood-2015-03-637728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4692143PMC
December 2015

Vascular safety issues in CML patients treated with BCR/ABL1 kinase inhibitors.

Blood 2015 Feb 18;125(6):901-6. Epub 2014 Dec 18.

Medical Clinic for Hematology and Oncology, Campus Virchow, Charité, Medical University of Berlin, Berlin, Germany.

Vascular safety is an emerging issue in patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKIs). Whereas imatinib exhibits a well-documented and favorable long-term safety profile without obvious accumulation of vascular events, several types of vascular adverse events (VAEs) have been described in patients receiving second- or third-generation BCR/ABL1 TKIs. Such VAEs include pulmonary hypertension in patients treated with dasatinib, peripheral arterial occlusive disease and other arterial disorders in patients receiving nilotinib, and venous and arterial vascular occlusive events during ponatinib. Although each TKI interacts with a unique profile of molecular targets and has been associated with a unique pattern of adverse events, the mechanisms of drug-induced vasculopathy are not well understood. Here, recent data and concepts around VAEs in TKI-treated patients with CML are discussed, with special reference to potential mechanisms, event management, and strategies aimed at avoiding occurrence of such events in long-term treated patients.
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http://dx.doi.org/10.1182/blood-2014-09-594432DOI Listing
February 2015

Identification of heat shock protein 32 (Hsp32) as a novel target in acute lymphoblastic leukemia.

Oncotarget 2014 Mar;5(5):1198-211

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Austria.

Heat shock proteins (Hsp) are increasingly employed as therapeutic targets in oncology. We have shown that Hsp32, also known as heme oxygenase-1 (HO-1), serves as survival factor and potential target in Ph+ chronic myeloid leukemia. We here report that primary cells and cell lines derived from patients with acute lymphoblastic leukemia (ALL) express Hsp32 mRNA and the Hsp32 protein in a constitutive manner. Highly enriched CD34+/CD38- ALL stem cells also expressed Hsp32. Two Hsp32-targeting drugs, pegylated zinc protoporphyrine (PEG-ZnPP) and styrene maleic acid-micelle-encapsulated ZnPP (SMA-ZnPP), induced apoptosis and growth arrest in the BCR/ABL1+ cell lines, in Ph- lymphoblastic cell lines and in primary Ph+ and Ph- ALL cells. The effects of PEG-ZnPP and SMA-ZnPP on growth of leukemic cells were dose-dependent. In Ph+ ALL, major growth-inhibitory effects of the Hsp32-targeting drugs were observed in imatinib-sensitive and imatinib-resistant cells. Hsp32-targeting drugs were found to synergize with imatinib, nilotinib, and bendamustine in producing growth inhibition and apoptosis in Ph+ ALL cells. A siRNA against Hsp32 was found to inhibit growth and survival of ALL cells and to synergize with imatinib in suppressing the growth of ALL cells. In conclusion, Hsp32 is an essential survival factor and potential new target in ALL.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012724PMC
http://dx.doi.org/10.18632/oncotarget.1805DOI Listing
March 2014

A new human mast cell line expressing a functional IgE receptor converts to tumorigenic growth by KIT D816V transfection.

Blood 2014 Jul 27;124(1):111-20. Epub 2014 Mar 27.

Laboratoire de Biologie et Pharmacologie Appliquée, Centre Nationale de la Recherche, Unité Mixte de Recherche 8113, Ecole Normale Supérieure de Cachan, Cachan, France; Laboratoire Central d'Hématologie, Groupe Hospitalier Pitié-Salpêtrière, Paris, France;

In systemic mastocytosis (SM), clinical problems arise from factor-independent proliferation of mast cells (MCs) and the increased release of mediators by MCs, but no human cell line model for studying MC activation in the context of SM is available. We have created a stable stem cell factor (SCF) -dependent human MC line, ROSA(KIT WT), expressing a fully functional immunoglobulin E (IgE) receptor. Transfection with KIT D816V converted ROSA(KIT WT) cells into an SCF-independent clone, ROSA(KIT D816V), which produced a mastocytosis-like disease in NSG mice. Although several signaling pathways were activated, ROSA(KIT D816V) did not exhibit an increased, but did exhibit a decreased responsiveness to IgE-dependent stimuli. Moreover, NSG mice bearing ROSA(KIT D816V)-derived tumors did not show mediator-related symptoms, and KIT D816V-positive MCs obtained from patients with SM did not show increased IgE-dependent histamine release or CD63 upregulation. Our data show that KIT D816V is a disease-propagating oncoprotein, but it does not activate MCs to release proinflammatory mediators, which may explain why mediator-related symptoms in SM occur preferentially in the context of a coexisting allergy. ROSA(KIT D816V) may provide a valuable tool for studying the pathogenesis of mastocytosis and should facilitate the development of novel drugs for treating SM patients.
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http://dx.doi.org/10.1182/blood-2013-10-534685DOI Listing
July 2014

Co-operating STAT5 and AKT signaling pathways in chronic myeloid leukemia and mastocytosis: possible new targets of therapy.

Haematologica 2014 Mar;99(3):417-29

Chronic myeloid leukemia and systemic mastocytosis are myeloid neoplasms sharing a number of pathogenetic and clinical features. In both conditions, an aberrantly activated oncoprotein with tyrosine kinase activity, namely BCR-ABL1 in chronic myeloid leukemia, and mutant KIT, mostly KIT D816V, in systemic mastocytosis, is key to disease evolution. The appreciation of the role of such tyrosine kinases in these diseases has led to the development of improved therapies with tyrosine kinase-targeted inhibitors. However, most drugs, including new KIT D816V-blocking agents, have failed to achieve long-lasting remissions in advanced systemic mastocytosis, and there is a similar problem in chronic myeloid leukemia, where imatinib-resistant patients sometimes fail to achieve remission, even with second- or third-line BCR-ABL1 specific tyrosine kinase inhibitors. During disease progression, additional signaling pathways become activated in neoplastic cells, but most converge into major downstream networks. Among these, the AKT and STAT5 pathways appear most critical and may result in drug-resistant chronic myeloid leukemia and systemic mastocytosis. Inhibition of phosphorylation of these targets has proven their crucial role in disease-evolution in both malignancies. Together, these observations suggest that STAT5 and AKT are key drivers of oncogenesis in drug-resistant forms of the diseases, and that targeting STAT5 and AKT might be an interesting approach in these malignancies. The present article provides an overview of our current knowledge about the critical role of AKT and STAT5 in the pathophysiology of chronic myeloid leukemia and systemic mastocytosis and on their potential value as therapeutic targets in these neoplasms.
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http://dx.doi.org/10.3324/haematol.2013.098442DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943304PMC
March 2014

Phenotyping of human melanoma cells reveals a unique composition of receptor targets and a subpopulation co-expressing ErbB4, EPO-R and NGF-R.

PLoS One 2014 29;9(1):e84417. Epub 2014 Jan 29.

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Vienna, Austria ; Division of Hematology & Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria.

Malignant melanoma is a life-threatening skin cancer increasingly diagnosed in the western world. In advanced disease the prognosis is grave. Growth and metastasis formation in melanomas are regulated by a network of cytokines, cytokine-receptors, and adhesion molecules. However, little is known about surface antigens and target expression profiles in human melanomas. We examined the cell surface antigen profile of human skin melanoma cells by multicolor flow cytometry, and compared their phenotype with 4 melanoma cell lines (A375, 607B, Mel-Juso, SK-Mel28). Melanoma cells were defined as CD45-/CD31- cells co-expressing one or more melanoma-related antigens (CD63, CD146, CD166). In most patients, melanoma cells exhibited ErbB3/Her3, CD44/Pgp-1, ICAM-1/CD54 and IGF-1-R/CD221, but did not express CD20, ErbB2/Her2, KIT/CD117, AC133/CD133 or MDR-1/CD243. Melanoma cell lines were found to display a similar phenotype. In most patients, a distinct subpopulation of melanoma cells (4-40%) expressed the erythropoietin receptor (EPO-R) and ErbB4 together with PD-1 and NGF-R/CD271. Both the EPO-R+ and EPO-R- subpopulations produced melanoma lesions in NOD/SCID IL-2Rgamma(null) (NSG) mice in first and secondary recipients. Normal skin melanocytes did not express ErbB4 or EPO-R, but expressed a functional KIT receptor (CD117) as well as NGF-R, ErbB3/Her3, IGF-1-R and CD44. In conclusion, melanoma cells display a unique composition of surface target antigens and cytokine receptors. Malignant transformation of melanomas is accompanied by loss of KIT and acquisition of EPO-R and ErbB4, both of which are co-expressed with NGF-R and PD-1 in distinct subfractions of melanoma cells. However, expression of EPO-R/ErbB4/PD-1 is not indicative of a selective melanoma-initiating potential.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0084417PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906015PMC
September 2014

The pan-Bcl-2 blocker obatoclax promotes the expression of Puma, Noxa, and Bim mRNA and induces apoptosis in neoplastic mast cells.

J Leukoc Biol 2014 Jan 19;95(1):95-104. Epub 2013 Sep 19.

1.Division of Hematology and Hemostaseology and Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, A-1090 Vienna, Austria.

Advanced SM is an incurable neoplasm with short survival time. So far, no effective therapy is available for these patients. We and others have shown recently that neoplastic MC in ASM and MCL express antiapoptotic Mcl-1, Bcl-2, and Bcl-xL. In this study, we examined the effects of the pan-Bcl-2 family blocker obatoclax (GX015-070) on primary neoplastic MC, the human MC leukemia cell line HMC-1, and the canine mastocytoma cell line C2. Obatoclax was found to inhibit proliferation in primary human neoplastic MC (IC₅₀: 0.057 μM), in HMC-1.2 cells expressing KIT D816V (IC₅₀: 0.72 μM), and in HMC-1.1 cells lacking KIT D816V (IC₅₀: 0.09 μM), as well as in C2 cells (IC₅₀: 0.74 μM). The growth-inhibitory effects of obatoclax in HMC-1 cells were accompanied by an increase in expression of Puma, Noxa, and Bim mRNA, as well as by apoptosis, as evidenced by microscopy, TUNEL assay, and caspase cleavage. Viral-mediated overexpression of Mcl-1, Bcl-xL, or Bcl-2 in HMC-1 cells was found to introduce partial resistance against apoptosis-inducing effects of obatoclax. We were also able to show that obatoclax synergizes with several other antineoplastic drugs, including dasatinib, midostaurin, and bortezomib, in producing apoptosis and/or growth arrest in neoplastic MC. Together, obatoclax exerts major growth-inhibitory effects on neoplastic MC and potentiates the antineoplastic activity of other targeted drugs. Whether these drug effects can be translated to application in patients with advanced SM remains to be determined.
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http://dx.doi.org/10.1189/jlb.1112609DOI Listing
January 2014

Guidelines and diagnostic algorithm for patients with suspected systemic mastocytosis: a proposal of the Austrian competence network (AUCNM).

Am J Blood Res 2013 5;3(2):174-80. Epub 2013 May 5.

Department of Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna Austria ; Ludwig Boltzmann Cluster Oncology, Medical University of Vienna Austria.

Systemic mastocytosis (SM) is a hematopoietic neoplasm characterized by pathologic expansion of tissue mast cells in one or more extracutaneous organs. In most children and most adult patients, skin involvement is found. Childhood patients frequently suffer from cutaneous mastocytosis without systemic involvement, whereas most adult patients are diagnosed as suffering from SM. In a smaller subset of patients, SM without skin lesions develops which is a diagnostic challenge. In the current article, a diagnostic algorithm for patients with suspected SM is proposed. In adult patients with skin lesions and histologically confirmed mastocytosis in the skin (MIS), a bone marrow biopsy is recommended regardless of the serum tryptase level. In adult patients without skin lesions who are suffering from typical mediator-related symptoms, the basal serum tryptase level is an important diagnostic parameter. In those with slightly elevated tryptase (15-30 ng/ml), additional non-invasive investigations, including a KIT mutation analysis of peripheral blood cells and sonographic analysis, is performed. In adult patients in whom i) KIT D816V is detected or/and ii) the basal serum tryptase level is clearly elevated (> 30 ng/ml) or/and iii) other clinical or laboratory features are suggesting the presence of occult mastocytosis, a bone marrow biopsy should be performed. In the absence of KIT D816V and other indications of mastocytosis, no bone marrow investigation is required, but the patient's course and the serum tryptase levels are examined in the follow-up.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649810PMC
May 2013

Synergistic growth-inhibitory effects of ponatinib and midostaurin (PKC412) on neoplastic mast cells carrying KIT D816V.

Haematologica 2013 Sep 28;98(9):1450-7. Epub 2013 Mar 28.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Austria.

Patients with advanced systemic mastocytosis, including mast cell leukemia, have a poor prognosis. In these patients, neoplastic mast cells usually harbor the KIT mutant D816V that confers resistance against tyrosine kinase inhibitors. We examined the effects of the multi-kinase blocker ponatinib on neoplastic mast cells and investigated whether ponatinib acts synergistically with other antineoplastic drugs. Ponatinib was found to inhibit the kinase activity of KIT G560V and KIT D816V in the human mast cell leukemia cell line HMC-1. In addition, ponatinib was found to block Lyn- and STAT5 activity in neoplastic mast cells. Ponatinib induced growth inhibition and apoptosis in HMC-1.1 cells (KIT G560V(+)) and HMC-1.2 cells (KIT G560V(+)/KIT D816V(+)) as well as in primary neoplastic mast cells. The effects of ponatinib were dose-dependent, but higher IC50-values were obtained in HMC-1 cells harboring KIT D816V than in those lacking KIT D816V. In drug combination experiments, ponatinib was found to synergize with midostaurin in producing growth inhibition and apoptosis in HMC-1 cells and primary neoplastic mast cells. The ponatinib+midostaurin combination induced substantial inhibition of KIT-, Lyn-, and STAT5 activity, but did not suppress Btk. We then applied a Btk short interfering RNA and found that Btk knockdown sensitizes HMC-1 cells against ponatinib. Finally, we were able to show that ponatinib synergizes with the Btk-targeting drug dasatinib to produce growth inhibition in HMC-1 cells. In conclusion, ponatinib exerts major growth-inhibitory effects on neoplastic mast cells in advanced systemic mastocytosis and synergizes with midostaurin and dasatinib in inducing growth arrest in neoplastic mast cells.
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http://dx.doi.org/10.3324/haematol.2012.079202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3762103PMC
September 2013

European Competence Network on Mastocytosis (ECNM): 10-year jubilee, update, and future perspectives.

Wien Klin Wochenschr 2012 Dec 20;124(23-24):807-14. Epub 2012 Nov 20.

Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.

The European Competence Network on Mastocytosis (ECNM) was initiated in 2002 as a multidisciplinary and multinational cooperative approach to increase awareness and to improve diagnosis and therapy of mastocytosis. The network is composed of local centers, physicians, and scientists who have dedicated their work to patients with mastocytosis. A strategic goal of the ECNM is to provide the best available information about the disease to patients and physicians. During the past 10 years, the ECNM has expanded to various countries and contributed successfully to the development of markers, definitions, and standards in the field of mastocytosis. Members of the ECNM organized Annual Meetings in Europe and two Working Conferences on Mastocytosis in Vienna (in 2005 and 2010), and initiated and supported several preclinical and clinical trials. In all these activities, representatives of the ECNM cooperate closely with their US colleagues, with patient-organizations in Europe and in the USA, and with other scientific networks. The ECNM also launched a mastocytosis registry that has been activated in 2012. Using the central database of this registry, cooperative multicenter studies, which should include sufficient numbers of patients and robust evaluations, will be conducted. These studies will increase our knowledge about optimal management and therapy of patients with mastocytosis in the future.
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http://dx.doi.org/10.1007/s00508-012-0293-zDOI Listing
December 2012

5-azacytidine and decitabine exert proapoptotic effects on neoplastic mast cells: role of FAS-demethylation and FAS re-expression, and synergism with FAS-ligand.

Blood 2012 May 21;119(18):4242-52. Epub 2012 Mar 21.

Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, Austria

Aggressive systemic mastocytosis (ASM) and mast cell leukemia (MCL) are advanced hematopoietic neoplasms with poor prognosis. In these patients, neoplastic mast cells (MCs) are resistant against various drugs. We examined the effects of 2 demethylating agents, 5-azacytidine and decitabine on growth and survival of neoplastic MCs and the MC line HMC-1. Two HMC-1 subclones were used, HMC-1.1 lacking KIT D816V and HMC-1.2 exhibiting KIT D816V. Both agents induced apoptosis in HMC-1.1 and HMC-1.2 cells. Decitabine, but not 5-azacytidine, also produced a G(2)/M cell-cycle arrest in HMC-1 cells. Drug-induced apoptosis was accompanied by cleavage of caspase-8 and caspase-3 as well as FAS-demethylation and FAS-re-expression in neoplastic MCs. Furthermore, both demethylating agents were found to synergize with the FAS-ligand in inducing apoptosis in neoplastic MCs. Correspondingly, siRNA against FAS was found to block drug-induced expression of FAS and drug-induced apoptosis in HMC-1 cells. Neither 5-azacytidine nor decitabine induced substantial apoptosis or growth arrest in normal MCs or normal bone marrow cells. Together, 5-azacytidine and decitabine exert growth-inhibitory and proapoptotic effects in neoplastic MCs. These effects are mediated through "FAS-re-expression" and are augmented by the FAS-ligand. Whether epigenetic drugs produce antineoplastic effects in vivo in patients with ASM and MCL remains to be determined.
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http://dx.doi.org/10.1182/blood-2011-09-382770DOI Listing
May 2012

The PI3-kinase/mTOR-targeting drug NVP-BEZ235 inhibits growth and IgE-dependent activation of human mast cells and basophils.

PLoS One 2012 27;7(1):e29925. Epub 2012 Jan 27.

Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria.

The phosphoinositide 3-kinase (PI3-kinase) and the mammalian target of rapamycin (mTOR) are two major signaling molecules involved in growth and activation of mast cells (MC) and basophils (BA). We examined the effects of the dual PI3-kinase/mTOR blocker NVP-BEZ235 on growth of normal and neoplastic BA and MC as well as immunoglobulin E (IgE)-dependent cell activation. Growth of MC and BA were determined by measuring (3)H-thymidine uptake and apoptosis. Cell activation was determined in histamine release experiments and by measuring upregulation of CD63 and CD203c after challenging with IgE plus anti-IgE or allergen. We found that NVP-BEZ235 exerts profound inhibitory effects on growth of primary and cloned neoplastic MC. In the MC leukemia cell line HMC-1, NVP-BEZ235 showed similar IC(50) values in the HMC-1.1 subclone lacking KIT D816V (0.025 µM) and the HMC-1.2 subclone expressing KIT D816V (0.005 µM). Moreover, NVP-BEZ235 was found to exert strong growth-inhibitory effects on neoplastic MC in a xenotransplant-mouse model employing NMR1-Foxn1(nu) mice. NVP-BEZ235 also exerted inhibitory effects on cytokine-dependent differentiation of normal BA and MC, but did not induce growth inhibition or apoptosis in mature MC or normal bone marrow cells. Finally, NVP-BEZ235 was found to inhibit IgE-dependent histamine release in BA and MC (IC(50) 0.5-1 µM) as well as anti-IgE-induced upregulation of CD203c in BA and IgE-dependent upregulation of CD63 in MC. In summary, NVP-BEZ235 produces growth-inhibitory effects in immature neoplastic MC and inhibits IgE-dependent activation of mature BA and MC. Whether these potentially beneficial drug effects have clinical implications is currently under investigation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029925PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3267720PMC
July 2012

KIT-D816V-independent oncogenic signaling in neoplastic cells in systemic mastocytosis: role of Lyn and Btk activation and disruption by dasatinib and bosutinib.

Blood 2011 Aug 16;118(7):1885-98. Epub 2011 Jun 16.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Vienna, Austria.

Systemic mastocytosis (SM) either presents as a malignant neoplasm with short survival or as an indolent disease with normal life expectancy. In both instances, neoplastic mast cells (MCs) harbor D816V-mutated KIT, suggesting that additional oncogenic mechanisms are involved in malignant transformation. We here describe that Lyn and Btk are phosphorylated in a KIT-independent manner in neoplastic MCs in advanced SM and in the MC leukemia cell line HMC-1. Lyn and Btk activation was not only detected in KIT D816V-positive HMC-1.2 cells, but also in the KIT D816V-negative HMC-1.1 subclone. Moreover, KIT D816V did not induce Lyn/Btk activation in Ba/F3 cells, and deactivation of KIT D816V by midostaurin did not alter Lyn/Btk activation. siRNAs against Btk and Lyn were found to block survival in neoplastic MCs and to cooperate with midostaurin in producing growth inhibition. Growth inhibitory effects were also obtained with 2 targeted drugs, dasatinib which blocks KIT, Lyn, and Btk activation in MCs, and bosutinib, a drug that deactivates Lyn and Btk without blocking KIT activity. Together, KIT-independent signaling via Lyn/Btk contributes to growth of neoplastic MCs in advanced SM. Dasatinib and bosutinib disrupt Lyn/Btk-driven oncogenic signaling in neoplastic MC, which may have clinical implications and explain synergistic drug interactions.
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http://dx.doi.org/10.1182/blood-2010-06-289959DOI Listing
August 2011