Leukemia Driven By a NUP98-Phd Domain Fusion Is Highly Sensitive To Disruption Of H3K4me3-Phd Domain Binding By a Small Molecule Inhibitor

Abstract NUP98 gene fusions, created by non-random chromosomal translocations, are associated with a wide spectrum of high risk hematologic malignancies, and typically lead to overexpression of abdominal-b HOXA genes, a common theme shared by ∼50% of AML patients. We have generated a transgenic mouse model of the NUP98-PHF23 (NP23) gene fusion, initially identified in patients with AML, which develop AML, erythroleukemia, pre-T lymphoblastic leukemia (pre-T LBL), and a novel pre-B1 B cell acute lymphoblastic leukemia (pre-B1 ALL). A common theme in the leukemias and the premalignant hematopoietic tissues, is the overexpression of a Hoxa/b +Meis1 stem cell-like gene expression signature. GSEA analysis reveals this signature to be enriched in both human AML and ALL malignancies, and in human HSPC profiles. In addition, we found Bahcc1, a gene not previously associated with malignancy, to consistently segregate with the Hoxa/b+Meis1 signature in the NP23 leukemias and the premalignant tissues, independent of hematopoietic cell lineage. Furthermore, data-mining revealed BAHCC1 to be markedly overexpressed in AML patients with HOXA9/MEIS1 overexpression, and in a subset of MLL rearranged pre-B-ALL patients, suggesting BAHCC1 may be a previously unsuspected marker of leukemic transformation. NUP98-PHF23 belongs to a subset of fusion oncoproteins (including some MLL- and NUP98-fusions) that are potently tumorigenic and act by abrogating the normal reading, writing and erasure of histone methylation. Wild type PHF23 binds H3K4me3 residues via a PHD domain, therefore we used ChIP-seq to characterize global chromatin H3K4me3 and NP23 enrichment in NP23 leukemia derived cell lines. The vast majority (88%) of NP23 binding sites were enriched for H3K4me3 binding. Conversely, the NP23 protein co-localized at only 1.6% of all H3K4me3 enriched sites (including Hoxa, Hoxb and Meis1 loci) identifying these sites as direct targets of the NP23 fusion protein. Given that the NP23 fusion appears to function, at least in part, via binding to H3K4me3 sites at specific loci, we hypothesized that NP23 cells would be sensitive to disruption of the H3K4me4 binding by the NP23 PHD domain. Treatment of leukemic NP23 cells with Tetraethylthiuram disulfide (Disulfiram), a small molecule shown to inhibit PHD domain binding of H3K4me3 marks in vitro, rapidly and selectively killed NP23 myeloblasts but not control myeloblast cell lines (188G3, 189E6 and 32D) at 2 µM. Cell death was rapid, being 100% complete within 24 hours. Cell death was preceded by decreased levels of NP23 protein bound at target loci and decreased expression of these loci (e.g., Hoxa7/9/10, Hoxb5 and Meis1). We conclude that inhibitors of H3K4me3 PHD domain readers are promising therapeutic compounds that can kill leukemic cells driven by proteins that aberrantly read or write the histone code. The NP23 model provides a robust platform on which to identify and improve such compounds. Disclosures: Denu: Sirtris-GSK: Consultancy.

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IPI-504, a Novel, Orally Active HSP90 Inhibitor, Prolongs Survival of Mice with BCR-ABL T315I CML and B-ALL.

Blood ◽

10.1182/blood.v108.11.2183.2183 ◽

2006 ◽

Vol 108 (11) ◽

pp. 2183-2183 ◽

Cited By ~ 1

Author(s):

Cong Peng ◽

Julia Brain ◽

Yiguo Hu ◽

Linghong Kong ◽

David Grayzel ◽

...

Keyword(s):

Cell Lines ◽

Median Survival ◽

Combination Treatment ◽

Lymphoblastic Leukemia ◽

Hsp90 Inhibitor ◽

Leukemic Cells ◽

Prolonged Survival ◽

Hsp90 Inhibition ◽

T315i Mutation

Abstract Development of mutations within the kinase domain is a major drug-resistance mechanism for tyrosine kinase inhibitors (TKIs) in cancer therapy. In CML (chronic myeloid leukemia), a disease driven by the constitutively active BCR-ABL oncoprotein, no available TKIs have been effective in treating patients with the BCR-ABL T315I mutation. Heat shock protein 90 (Hsp90) is a highly conserved, constitutively expressed molecular chaperone that facilitates folding of client proteins like BCR-ABL, and affects the stability of these proteins. Several labs have shown that Hsp90 inhibition in vitro results in the degradation of BCR-ABL T315I and induces potent killing of these cell lines. However, these results have not been demonstrated in animal models for BCR-ABL-induced CML and B-ALL (B-cell acute lymphoblastic leukemia, a disease that does not respond well to TKIs including imatinib and dasatinib). Thus, IPI-504, an orally administered Hsp90 inhibitor, was evaluated in murine models of CML and B-ALL. Treatment of mice with wild type (WT)- or T315I BCR-ABL-induced CML with IPI-504 resulted in BCR-ABL protein degradation and a decrease in circulating BCR-ABL positive cells. In response to treatment with vehicle the median survival time of WT and T315I CML mice is approximately 20 days. While the T315I CML mice were resistant to imatinib with a median survival of 21 days, IPI-504 (50 and 100 mg/kg, PO TIW) demonstrated dose-dependent prolonged survival of these mice by 30 and 70 days, respectively (p<0.001 for both doses). Both imatinib and IPI-504 similarly prolonged survival of mice with BCR-ABL-WT-induced CML. In the T315I CML mice prolonged survival of the IPI-504 treated cohort was associated with decreased peripheral blood BCR-ABL positive leukemia cells during treatment, less splenomegaly and improved pulmonary histopathlogy at necropsy. In CML mice receiving mixed BCR-ABL-WT- or T315I-transduced donor bone marrow cells, Hsp90 inhibition more potently suppressed T315I-expressing leukemia clones relative to the WT clones, consistent with in vitro studies where T315I BCR-ABL was more sensitive to IPI-504 induced degradation in cell lines than WT BCR-ABL. Combination treatment with IPI-504 and imatinib was more effective than either treatment alone in prolonging survival of mice bearing both WT and T315I leukemic cells. IPI-504 also significantly prolonged survival of B-ALL mice bearing the T315I mutation (p<0.001). These results provide a rationale for use of an Hsp90 inhibitor as a novel approach to overcoming resistance to TKIs as well as the potential for first line combination treatment in CML patients. The potential for IPI-504 to eliminate mutant kinases via Hsp90 inhibition provides a new therapeutic strategy for treating BCR-ABL-induced CML, ALL as well as other cancers resistant to treatment with TKIs.

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Glucocorticoid Induced Cell Death Is Mediated by Its Effect on Cellular Metabolism and Is Independent of Caspase Activity.

Blood ◽

10.1182/blood.v110.11.3475.3475 ◽

2007 ◽

Vol 110 (11) ◽

pp. 3475-3475

Author(s):

Sandeep Gurbuxani

Keyword(s):

Cell Death ◽

Cell Lines ◽

Lymphoblastic Leukemia ◽

Lactate Concentration ◽

Cellular Metabolism ◽

Mechanisms Of Resistance ◽

Metabolic State ◽

Childhood All ◽

Mitochondrial Mass

Glucocorticoids (GCs) such as prednisone and dexamethasone are a crucial component of acute lymphoblastic leukemia (ALL) therapy protocols. Multiple studies in childhood ALL have demonstrated that resistance to GC mediated cell death in vitro and in vivo is the single most important predictor of treatment outcome in childhood ALL. However, the mechanisms of GC mediated cell death as well as the mechanisms of resistance are poorly understood. The present study was undertaken to better understand the mechanism of GC induced cell death and to delineate possible mechanisms of resistance. In the initial experiments performed, multiple ALL cell lines, when treated with dexamethasone, underwent a reduction in the amount of reactive oxygen species (ROS) followed by cell cycle arrest and finally cell death which was unaffected by the presence of a pan-caspase inhibitor z-VAD-fmk. Since the amount of ROS present in a cell is an indicator of the metabolic state of the cell, specifically the amount of oxidative phosphorylation going on in the mitochondria, additional experiments were performed to directly estimate the mitochondrial mass as well as the metabolic state of the cells treated with GCs. While the mitochondrial mass measured by Mitotracker green labeling of mitochondria in the viable cells remained unchanged in cell lines susceptible to low concentrations (nano or micromolar) of dexamethasone, there was a prominent reduction in mitochondrial mass 36 hours after dexamethasone exposure in MOLT-4 cell line that requires several fold higher (millimolar) concentration of dexamethasone to induce cell death. The reduction in ROS was not accompanied by an increase in glycolysis as determined by the measurement of lactate concentration in the culture supernatants either in the susceptible or the resistant cells. Since one possible mechanism of reduction in ROS is increased scavenging by molecules that are dependent on the presence of NADPH generated during glucose metabolism via the pentose phosphate pathway (PPP), additional experiments were performed to determine if chemical inhibition of this pathway could augment dexamethasone induced cell death in ALL cell lines. Indeed, addition of transandosterone, an inhibitor of G6PD, the rate limiting enzyme of the PPP, resulted in significantly increased dexamethasone toxicity. Based on these experiments it can be concluded that GC induced cell death is mediated by its effect on cellular metabolism. Furthermore, this cell death is caspase independent and likely proceeds via a pathway mechanistically distinct from classical apoptosis. Finally, cells resistant to GC induced cell death have evolved mechanisms to adapt to GC induced changes in cellular metabolism and may maintain energy production via alternative pathways such as the PPP shunt that are independent of mitochondria.

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Role of Erythropoietin Receptor in t(12;21) Positive Acute Lymphoblastic Leukemia.

Blood ◽

10.1182/blood.v110.11.2792.2792 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2792-2792

Author(s):

Renate Panzer-Gruemayer ◽

Gerd Krapf ◽

Dominik Beck ◽

Gerhard Fuka ◽

Christian Bieglmayer ◽

...

Keyword(s):

Cell Lines ◽

Fusion Gene ◽

Lymphoblastic Leukemia ◽

Leukemic Cell ◽

Erythropoietin Receptor ◽

Molecular Signature ◽

Leukemic Cells ◽

Drug Induced ◽

Induced Apoptosis

Abstract The chromosomal translocation t(12;21)(p13;q22) resulting in the TEL/AML1 (also known as ETV6/ RUNX1) fusion gene is the most frequent translocation in childhood B cell precursor (BCP) ALL. This type of ALL is characterized by a unique molecular signature, which includes the overexpression of the gene for the erythropoietin receptor (EpoR). So far, it is not known what causes the overexpression of the EpoR gene or whether it has any effect on the t(12;21) positive leukemia. We therefore aimed to evaluate potential mechanisms responsible for the upregulation of the EpoR in t(12;21) leukemias and to find out whether signalling via this receptor affects survival or proliferation of leukemic cells. In addition, we planned to explore signalling pathways linked to the respective effects and to elucidate relevant mechanisms that might be essential for cell survival. We first excluded the possibility that the EpoR expression is upregulated as a consequence of high Epo levels in the plasma that are induced by the patients’ low hemoglobin (Hb) levels. While Hb levels from patients with t(12;21)+ ALL were significantly lower compared to those with other subtypes of BCP ALL (median, 6,15g/dL and 7,9g/dL, respectively; p<0.001 Wilcoxon 2- sample test), which correlated with high Epo levels in the plasma, the extent of EpoR mRNA expression of leukemic cells was independent of the respective amount of Epo in the individual patient’s plasma. Next, the influence of Epo on t(12;21) + leukemic cell lines was evaluated and revealed a consistent time and dose dependent increase in proliferation (Epo concentrations 10, 50, 100U/ml for 72 hours) determined by 3H-Thymidine incorporation. This effect was abrogated upon addition of a blocking anti-EpoR antibody thereby confirming the specificity of EpoR signalling. Since Epo may have apoptosis-modulating potential in EpoR expressing malignant cells, we tested its influence on drug-induced apoptosis. For this purpose IC50 concentrations of drugs that are commonly used for the treatment of children with BCP ALL were used. A reduction of glucocorticoid (GC)-induced apoptosis by Epo was demonstrated in t(12;21)+ cell lines while no effect was seen in combination with other drugs or in t(12;21) negative cell lines. Preliminary data indicate that NF-kappa B as well as PI3K/Akt pathways are triggered by Epo, implying that they play a role in this rescue mechanism. Given that cell lines may have intrinsic changes, we are presently evaluating whether the observed results can also be reproduced in primary leukemic cells. In support of this assumption are results in a limited number of primary t(12;21)+ leukemias showing a superior survival (MTT assay) and reduced apoptosis rate to GC when cultured in the presence of Epo. These findings are in contrast to those in t(12;21) negative BCP ALLs. In conclusion, our data indicate that overexpression of EpoR in t(12;21) positive leukemias is not induced by low Hb, a feature that is generally observed in patients with this type of leukemia. Binding of Epo to its receptor in vitro leads to enhanced survival and negatively affects the sensitivity to GCs. Whether these findings have any implications on the treatment and care of patients with t(12;21)+ leukemia needs to be addressed in further studies. Financial support: OENB10720, FWF P17551-B14 and GENAU-CHILD Projekt GZ200.136/1 - VI/1/2005 to RPG.

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Synergistic Activity of the Novel Src/Abl Inhibitor Bosutinib in Combination with Imatinib.

Blood ◽

10.1182/blood.v110.11.2930.2930 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2930-2930 ◽

Cited By ~ 2

Author(s):

Sara Redaelli ◽

Frank Boschelli ◽

Michela Viltadi ◽

Iris Meneghetti ◽

Carlo Gambacorti

Keyword(s):

Synergistic Effect ◽

Cell Lines ◽

Synergistic Effects ◽

Lymphoblastic Leukemia ◽

Leukemic Cells ◽

Synergistic Activity ◽

Binding Modes ◽

Imatinib Resistant ◽

Wide Range

Abstract The oncogenic fusion protein Bcr-Abl is the underlying cause of Chronic Myeloid Leukemia (CML), and it is present in up to 35% of Acute Lymphoblastic Leukemia (ALL). The discovery of a selective Abl inhibitor, Imatinib mesylate, has revolutionized the treatment of CML. Recently, several new inhibitors have been developed with the aim of increasing both potency and selectivity against Abl. Bosutinib (SKI-606, Wyeth) is a dual Src/Abl inhibitor that showed an in vitro activity in the low nanomolar range on several BCR-ABL positive cells and it is, at present, in phase II clinical trials. Bosutinib is devoid of activity against some known “off-target” kinases blocked by imatinib, such as PDGFR and c-Kit. In addition structural and modelling data attribute to Bosutinib the ability to bind Bcr-Abl in the intermediate/active conformation, while Imatinib is able to bind only the inactive conformation of Bcr-Abl. In this study we analyzed in vitro the combination of Imatinib and Bosutinib in Bcr-Abl expressing cell lines to evaluate the possibility to decrease dosage of both drugs, increasing or maintaining the same efficacy but avoiding toxic effects. Combination effects were evaluated according to the method of Chou and Talalay, in which the combination index (CI) value is calculated for a combination of two drugs and allows the quantification of synergism: CI <1, =1 or >1 indicate synergistic, additive or antagonistic interactions, respectively. Proliferation assays on a panel of Imatinib-sensitive and Imatinib-resistant BCR-ABL positive cell lines were performed. Cells were treated with Imatinib and Bosutinib as single agents or in three ratio combinations (1:3, 1:10, 1:33 in favour to Imatinib) across a wide range of concentrations. Combination indexes (CI) calculated at IC50, IC75 and IC90 for K562 cells (Imatinib-sensitive), suggest a synergistic to very strong synergistic effect (CI= 0.01-0.53). Similarly, in KCl22, KU812 and Lama84 cells (Imatinib-sensitive) moderate to strong synergistic effects were observed. A slight to moderate synergism was also obtained in three Imatinib-resistant cell lines tested: Lama84R (CI=0.63-0.88), K562R (CI=0.63-0.82) and KCL22R (CI=0.62-0.92). Western blot analysis of the tyrosine phosphorylation status of K562S cells treated with a mixture of 100nM Imatinib and 10nM Bosutinib revealed a substantially more pronounced inhibition compared with either 100nM Imatinib or 10nM Bosutinib alone. The effect of the combination was also assessed in murine Ba/F3 cells transfected with either wild type (WT) or mutated forms of BCR-ABL. Parental Ba/F3 cells were not affected by the presence of both drugs, while in Ba/F3 BCR-ABL WT the CI ranged from 0.49 to 0.85, indicating moderate synergism. The combination of Imatinib and Bosutinib inhibited the growth of Ba/F3 BCR-ABL Y253F with a slight synergism (CI 0.77-0.87). No synergistic effect was observed on Ba/F3 BCR-ABL E255K and on the highly resistant T315I mutant. Fresh leukemic cells obtained from three CML patients were also studied. In these samples synergistic effects between Bosutinib and Imatinib were confirmed (CI=0.52, 0.73, 0.62). The different binding modes of Imatinib and Bosutinib may justify the synergistic effect observed in the CML lines. This results support a possible therapeutic advantage for the combination of Bosutinib and Imatinib against Philadelphia positive leukemias.

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FTY720 Has Potent Anti-Leukemic Effects on Acute Lymphoblastic Leukemia Cells and Results In Caspase Independent Cell Death

Blood ◽

10.1182/blood.v116.21.3260.3260 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3260-3260

Author(s):

Craig T. Wallington-Beddoe ◽

John Hewson ◽

Kenneth Francis Bradstock ◽

Linda J. Bendall

Keyword(s):

Flow Cytometry ◽

Cell Death ◽

Cell Lines ◽

Western Blotting ◽

Caspase 3 ◽

Lymphoblastic Leukemia ◽

Parp Cleavage ◽

Oxygen Species ◽

Ic50 Values

Abstract Abstract 3260 Introduction: Acute lymphoblastic leukemia (ALL) is the most common form of childhood cancer, which usually responds to chemotherapy. Long-term survival in adults is poor with most developing disease relapse, whilst Ph+ ALL has a particularly poor prognosis. FTY720 is an immunosuppressive drug that has recently demonstrated efficacy in phase 3 trials of relapsing/remitting multiple sclerosis. FTY720 also appears promising in a number of malignancies with the proposed mechanism being the reactivation of PP2A, a protein serine/threonine phosphatase whose activity may be reduced in malignant cells. Here we report findings of in vitro testing of FTY720 on Ph+ and negative ALL cell lines and primary patient samples, describing mechanisms of cell death. Methods: ALL cell lines and primary patient samples were treated with 1 nM - 100 μM FTY720 for 24 hours. Viability was measured by flow cytometry using propidium iodide and annexin V staining. Cellular proliferation was measured by 3H-thymidine incorporation. Flow cytometry and western blotting were used to measure caspase 3 activation whilst western blotting was used to assess caspase 3, PARP cleavage and LC3II formation. Electron microscopy permitted a detailed examination of cell ultra-structure and confocal microscopy with lysosensor blue staining enabled visualisation of acidic vacuoles. Reactive oxygen species generation was assessed by flow cytometry using the cell permeable dye carboxy-H2DCFDA. Results: FTY720 produced a profound reduction in proliferation and viability of Ph+ (ALL1 cells) and Ph− (REH, NALM6 and LK63 cells) cell lines and patient samples (n=7) in the low micromolar range. IC50 values for loss of viability at 24 hours ranged from 5.3 μM for ALL1 to 7.9 μM for LK63. The IC50 values for proliferation at 24 hours were 1.4 μM for ALL1 and 3.5 μM for REH. Caspase 3 activation was observed only at very low levels by flow cytometry whilst both caspase 3 and PARP cleavage were not detected by western blotting. Inhibition of caspases by ZVAD-FMK failed to rescue ALL cells from FTY720 induced cell death, demonstrating a caspase independent cell death mechanism. Light microscopy revealed prominent cytoplasmic vacuolation, and electron microscopy showed features consistent with autophagy and necrosis. Western blotting demonstrated strong LC3II bands and confocal microscopy, using lysosensor blue, revealed prominent acidic vacuolation, all confirming the induction of autophagy. Reactive oxygen species were generated in response to FTY720 treatment and partial reversal of this by N-acetyl-cysteine produced a concomitant increase in cell viability. PP2A inhibition with okadaic acid failed to rescue cells from FTY720-induced cell death. Conclusion: FTY720 is a highly active drug in vitro in ALL cell lines and patient samples. Evidence supports a caspase independent mechanism of cell death with the occurrence of autophagy and necrosis. PP2A activation is not solely responsible for leukemic cell death. Data on the in vivo effects of FTY720 on ALL cells in NOD-SCID mice will be presented. Disclosures: Bendall: Genzyme: Honoraria.

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Anti-Leukemic Activity of a Novel Pegylated Recombinant Erwinia Chrysanthemi-Derived L-Asparaginase On Lymphoid Cell Lines and Leukemia-Bearing Mouse Models.

Blood ◽

10.1182/blood.v120.21.2571.2571 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2571-2571 ◽

Cited By ~ 1

Author(s):

Wei-Wen Chien ◽

Céline Lebeux ◽

Nicolas Rachinel ◽

Soraya Allas ◽

Pierre Sahakian ◽

...

Keyword(s):

Cell Lines ◽

Lymphoblastic Leukemia ◽

Lymphoma Cell ◽

Erwinia Chrysanthemi ◽

Leukemic Cells ◽

Hypersensitivity Reactions ◽

Sensitive Cell ◽

Development Fund

Abstract Abstract 2571 Background: Bacterial-derived L-asparaginase (ASNase) is an indispensable component of the therapy of acute lymphoblastic leukemia (ALL). Despite the high rate of successful treatment, hypersensitivity reactions occur in 20–40 % of patients receiving this non-human protein, which limits the use of ASNase. Native Erwinia chrysanthemi-derived ASNase (n-crisantaspase) has been used for treating patients exhibiting allergic symptoms to native and PEGylated Escherichia coli-derived ASNases (EC-ASNase). However, hypersensitivity reactions are still observed in at least 17 % of patients receiving n-crisantaspase. A PEGylated recombinant Erwinia chrysanthemi-derived ASNase (PEG-r-crisantaspase) with improved pharmacokinetic and pharmacodynamics properties and reduced immunogenicity has been developed recently (Allas et al., abstracts #2003, #2034, ASH 2009). We present here the in vitro and in vivo evaluation of PEG-r-crisantaspase on leukemia and lymphoma cell lines and on a leukemia-bearing mouse model, respectively. Material and methods: Different cell lines (ALL, B, T and NK/T lymphoma) and bone marrow aspiration samples obtained from patients with B-ALL or T-ALL were exposed in vitro to increasing doses (0.00005 to 5 U/ml) of PEG-r-crisantaspase, n-crisantaspase, or native EC-ASNase for 3 days. The cytotoxicity of each molecule was evaluated using 3- (4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test. For the in vivo study, 5 millions of ASNase-sensitive cells, RS(4,11) were xenografted by intravenous injection (iv) into immunodeficient NOD/SCID mice. When 5% of leukemic blasts were observed in the blood of leukemia-bearing mice, 2, 5, 10 or 20 U/kg of PEG-r-crisantaspase or vehicle was injected intravenously in those mice. Two additional injections were performed with an interval of 7 days. Mice having significant weight loss (>20%) and/or extensive expansion of leukemic cells in blood (> 25%) and/or impaired general condition were sacrificed. Results: In vitro, PEG-r-crisantaspase and n-crisantaspase exhibited similar half maximal effective concentration (EC50) values for inhibiting the proliferation of leukemia and lymphoma cells. PEG-r-crisantaspase had a greater cytotoxicity effect on two high-sensitive cell lines than n-crisantaspase did, as shown by 4.5 and 8.1-fold-weaker EC50 values of PEG-r-crisantaspase relative to n-crisantaspase. PEG-r-crisantaspase, r-crisantaspase and n-crisantaspase were more efficient than EC-ASNase on less sensitive cell lines, which might be related to the 10-fold-greater glutaminase activity of crisantaspases than EC-ASNase. In vivo, after the first administration of PEG-r-crisantaspase in animals with ≥ 5% of leukemic cells, the leukemic cells were reduced to almost 0 % in mice within 4 days with all doses of PEG-r-crisantaspase tested, whereas the leukemic cells kept multiplying in the mice receiving vehicle. The 3 repeated injections of PEG-r-crisantaspase with an interval of 7 days delayed leukemia development for 17 days. All control mice receiving the vehicle had to be sacrificed at day 44 after leukemia inoculation, whereas of 28 mice receiving PEG-r-crisantaspase, 5 reached this endpoint at day 51 and the others at day 56. PEG-r-crisantaspase significantly improved the survival of leukemia-bearing mice for 7 to 12 days, regardless of the dose tested. Conclusions: These data provide evidence that PEG-r-crisantaspase has similar in vitro cytotoxic effect to n-crisantaspase on leukemia and lymphoma cell lines and significantly reduces the expansion of leukemic cells in leukemia-bearing mice, prolonging the survival of the animals. These results, together with preclinical PK/PD and immunogenicity data, support the clinical development of PEG-r-crisantaspase. A phase I dose escalation study in adult patients with relapsed or refractory hematological malignancies has been recently initiated. Research support from Alizé Pharma, the European Regional Development Fund (ERDF) and Grand Lyon. Disclosures: Allas: Alizé pharma: Employment. Sahakian:Alizé pharma: Employment. Julien:Alizé pharma: Employment. Abribat:Alizé pharma: Employment.

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Obinutuzumab (GA101) Significantly Enhances Cell Death and ADCC Compared to Rituximab Against CD20+ sensitive and Rituximab Resistant B-Cell Non-Hodgkin Lymphoma (NHL) and Lymphoblastic Leukemia (BLL)

Blood ◽

10.1182/blood.v120.21.4865.4865 ◽

2012 ◽

Vol 120 (21) ◽

pp. 4865-4865 ◽

Cited By ~ 1

Author(s):

Aradhana Awasthi Tiwari ◽

Janet Ayello ◽

Carmella van de Ven ◽

Danielle Glassman ◽

Anthony Sabulski ◽

...

Keyword(s):

Cell Death ◽

B Cell ◽

Nk Cells ◽

Cell Lines ◽

Caspase 3 ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Dismal Prognosis

Abstract Abstract 4865 Background: Patients who relapse with CD20+ B-NHL and B cell lymphoblastic leukemia (B-LL) have a dismal prognosis, often associated with chemotherapy resistance (Cairo et al. JCO, 2012,Mils/Cairo et al. BJH,2012) and often require alternative therapeutic strategies. Rituximab (RTX) in combination with FAB 96 chemotherapy is a safe, well-tolerated treatment that is associated with > 90% EFS in children with newly diagnosed and advanced mature B-Cell NHL (Cairo M.S. et al. ASCO, 2010). Resistance to RTX, however, may predispose patients with CD20+ NHL to an increase risk of relapse and or disease progression (Barth/Cairo et al. BJH, 2012; Tsai et al. Cl. Can. Res, 2012). Obinutuzumab (GA101), a novel type II glycoengineered CD20 antibody of the IgG1 isotype, mediates enhanced cell death vs RTX and has a glycoengineered Fc region that induces significantly enhanced ADCC (Mössner et al. Bld, 2010; Niederfellner G. et al. Bld, 2011; Bologna L et al. JI, 2012). Objective: To evaluate the in-vitro efficacy of GA101 compared to RTX against RTX sensitive and resistant CD20+ B-NHL and B-LL cell lines. Methods: Raji (CD20+,ATCC, Manhass, VA), U698-M (CD20+, DSMZ, Germany), Loucy cells (CD20−) (T-ALL) (ATCC, Manhass, VA) and Raji-2R and Raji-4RH (generously supplied by M. Barth, Roswell Park Cancer Institute) were cultured in RPMI with 10% FBS and incubated with GA101 and/or RTX at 100 μg/ml for 24 hrs (n=6), 48 and 72 hrs (n=5). Cell death was evaluated by staining with AnnexinV/7AAD and flow-cytometry. Loucy cells (CD20−) were used as the negative control. The caspase 3/7 activity was measured by FAM caspase 3/7 assay kit by FLICA™ methodology. RSCL, RRCL, U698-M and Loucy were incubated with GA101 and RTX treatment for 24, 48 and 72 hrs, and caspase3/7 activity was detected by FACS using 488 nm excitation and emission filter (n=3). ADCC were performed with K562-IL-15–41BBL expanded NK cells (Ayello/Cairo et al. ASH, 2010) as well as IL-2 expanded NK cells, at 20:1 effector: target ratio (E: T, n=3) using europium release assay (Perkin-Elmer). Results: GA101 induced significantly more cell death compared to RTX in B-NHL and BLL cell lines. (Table-1) GA101 vs RTX shows a significantly increase in caspase 3/7 activity in Raji 16.92±0.84% vs 11.76±0.08% compared to Raji2R 6.7±0.62% vs 2.8±0.7%, Raji4RH 5.8±0.35% vs 2.0±0.3% and U698-M 12.54±0.44% vs 9.6±0.95% compared to Loucy 3.22±0.45% vs 2.59±0.05%, respectively, at 24 hrs of treatment (p<0.0001). GA101 vs RTX also elicited a significant increase a ADCC with K562-IL15–41BBL expanded NK cells, in Raji 73.8±8.1% vs 56.81±4.6% compared to Raji-2R 38.0±2.0% vs 21.6±1.2%, Raji-4RH 40.0±1.6% vs 0.5±1.1% and U698-M 70.0±1.6% vs 45.56±0.1%, compared to Loucy 21.67±0.48% vs 15.92±0.52%, respectively (p<0.001) at day 7.The IL-2 alone expanded Hu-NK cells demonstrated a reduction of 10–20% cytotoxicity compared to K562-IL15–41BBL Hu-NK cells at day 7 against BLL, RSCL and RRCL, in-vitro. Conclusion: Obinutuzumab compared to RTX significantly enhanced cell death, caspase3/7 activity and NK mediated ADCC in sensitive and RTX resistant B-NHL and B-LL. Obinutuzumab represents a promising candidate for treating RTX sensitive and resistant CD20+ B-Cell Lymphomas and lymphoblastic leukemia. Further studies will investigate the combination of activated NK cells or chemotherapy that may enhance or synergize with the efficacy of GA101 (Obinutuzumab) both in -vitro and in-vivo in xenografted NOD/SCID mice. Disclosures: No relevant conflicts of interest to declare.

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Annona cherimola Seed Extract Activates Extrinsic and Intrinsic Apoptotic Pathways in Leukemic Cells

Toxins ◽

10.3390/toxins11090506 ◽

2019 ◽

Vol 11 (9) ◽

pp. 506 ◽

Cited By ~ 8

Author(s):

Tony Haykal ◽

Peter Nasr ◽

Mohammad H. Hodroj ◽

Robin I. Taleb ◽

Rita Sarkis ◽

...

Keyword(s):

Cell Death ◽

Cell Lines ◽

Apoptotic Cell ◽

Annexin V ◽

Seed Extract ◽

Leukemic Cells ◽

Western Blots ◽

Toxic Activity ◽

Annona Cherimola

Annona cherimola Mill is a large green fruit with black seeds widely known to possess toxic properties due to the presence of Annonaceous acetogenins. The present study investigates the anti-cancer properties of an Annona cherimola Mill ethanolic seed extract on Acute Myeloid Leukemia (AML) cell lines in vitro and elucidates the underlying cellular mechanism. The anti-proliferative effects of the extract on various AML cell lines and normal mesenchymal cells (MSCs) were assessed using WST-1 viability reagent. The pro-apoptotic effect of the extract was evaluated using Annexin V/PI staining and Cell Death ELISA. The underlying mechanism was deciphered by analyzing the expression of various proteins using western blots. Treatment with an A. cherimola seed ethanolic extract promotes a dose- and time-dependent inhibition of the proliferation of various AML cell lines, but not MSCs. Positive Annexin V staining, as well as DNA fragmentation, confirm an increase in apoptotic cell death by upregulating the expression of pro-apoptotic proteins which control both intrinsic and extrinsic pathways of apoptosis. GC/MS analysis revealed the presence of phytosterols, in addition to other bioactive compounds. In conclusion, Annona cherimola Mill seed extract, previously known to possess a potent toxic activity, induces apoptosis in AML cell lines by the activation of both the extrinsic and the intrinsic pathways.

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BCL-2, a Therapeutic Target for High Risk Hypodiploid B-Cell Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v128.22.280.280 ◽

2016 ◽

Vol 128 (22) ◽

pp. 280-280 ◽

Cited By ~ 5

Author(s):

Ernesto Diaz-Flores ◽

Evan Q. Comeaux ◽

Kailyn Kim ◽

Kyle Beckman ◽

Kara L. Davis ◽

...

Keyword(s):

Cell Death ◽

Acute Lymphoblastic Leukemia ◽

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Lymphoblastic Leukemia ◽

Advisory Committees ◽

Chromosomal Number ◽

Patient Derived Xenograft

Abstract Acute lymphoblastic leukemia (ALL) is the most common cancer of childhood. Specific genetic subsets, including hypodiploid ALL, are associated with particularly high rates of relapse. Despite the poor outcomes of hypodiploid B-ALL with traditional therapeutic approaches, there have been no known effective alternative therapies or novel candidates tested to improve outcome. We hypothesized that new therapeutic targets could by identified by integrated biochemical and genomic profiling, combined with functional drug assays in order to determine which pathways play an essential role in transformation. For biochemical profiling, we analyzed multiple pathways commonly deregulated in leukemias using phosphoflowcytometry (including receptor tyrosine kinases, JAK/STAT, MAPK, PI3K, PTEN, Bcl-2 survival and pro-apoptotic family members and p53). We subjected hypodiploid cell lines (NALM-16, MHH-CALL2) and patient derived xenograft samples in vitro to inhibitors against each of these pathways (PP2:Src family;Ruxolitinib: JAK/STAT; PD235901/CI1040: MAPK; GDC-0941, PI-90, PI-103, p110 (a, b, g, d): PI3K isoform specific; PP-242:mTOR; ABT-263/ABT-737: Bcl-2/Bcl-xl, and ABT-199: Bcl-2 specific). We found that the Bcl-2 inhibitors (ABT-263, ABT-737 and ABT-199) and to a lesser extent PI3K pathway inhibitors GDC-0941 and PP-242, but not the MAPK or RTK inhibitors, efficiently reduced proliferation of hypodiploid cells. However, only ABT-263/ABT-199 induced high levels of apoptosis at nanomolar concentrations. Based on the consistent efficacy observed with ABT-199 against hypodiploid patient-derived cells and cell lines in culture, we selected eight cryopreserved, previously xenografted (F3 generation) hypodiploid patient samples (4 low hypodiploid, chromosomal number between 32 and 39; and 4 Near Haploid, chromosomal number between 24 and 31) and three non-hypodiploid patient samples (Ph-positive,Ph-Like and Erg+) for a preclinical trial in immunodeficient mice. Each patient sample was engrafted into six mice, which were randomized to receive vehicle or ABT-199 daily over 60 days (Figure 1). Treatment started when the peripheral blood (PB) human CD45 count reached 15%. A rapid decrease in PB blasts was noted at 7 days (Figure 1). Eighty-five percent of the hypodiploid xenografts survived 60 days with either undetectable or low levels of leukemia in the PB. In contrastPh+ andPh-Like xenografts died within 10-20 days regardless of treatment. Importantly, hypodiploid leukemic blasts gradually emerged after discontinuing ABT-199 after 60 days. Additionally, despite low or undetectable levels of leukemic blasts in PB and reduced levels in bone marrow and spleen, all mice had high percentages of leukemic cells in the liver (Figure 2). In conclusion we have identified the survival protein Bcl-2 as a promising molecular target in hypodiploid B-ALL. ABT-199 for dramatically reduced leukemia cells in vitro and in vivo in patient-derived xenograft models of hypodiploid B-ALL. However, the liver represented a protective niche for these leukemias. In addition, our biochemical characterization of the organ infiltrating blasts collected from mice on trial indicate that the sensitivity of hypodiploid ALL to ABT-199 relies not only on high levels of Bcl-2 and deficiency for other survival proteins such as Bcl-xl but also on high levels of proapoptotic proteins, providing two different signatures that correlate with response to ABT-199. Using genome editing (CRISPR/Cas9) we interrogated the necessity for individual proapoptotic genes, including PUMA, NOXA, and BAD, for ABT-199-induced cell death. This study provides encouraging preclinical data that Bcl-2 may be a promising target for the treatment of hypodiploid B-ALL. Our studies identify signature biomarkers that correlate with drug response and identify essential proteins mediating ABT-199-induced cell death. Importantly, this report also identifies the limitations of using ABT-199 as single drug, and provides the rationale for using combinatorial therapies in order to improve the efficacy of the drug. Disclosures Mullighan: Loxo Oncology: Research Funding; Amgen: Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees. Loh:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding.

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Hydrocortisone does Not Influence in Vitro Glucocorticoid Sensitivity of Acute Lymphoblastic Leukemia Blasts

Blood ◽

10.1182/blood.v124.21.5228.5228 ◽

2014 ◽

Vol 124 (21) ◽

pp. 5228-5228

Author(s):

Lidewij T. Warris ◽

Marry M. van den Heuvel-Eibrink ◽

Ingrid M. Ariës ◽

Rob Pieters ◽

Erica L.T. van den Akker ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Side Effects ◽

Cell Lines ◽

Fluorescence Intensity ◽

Lymphoblastic Leukemia ◽

Leukemic Cell ◽

Leukemic Cells ◽

Glucocorticoid Sensitivity ◽

Leukemic Cell Lines

Abstract Introduction: Dexamethasone-induced neuropsychological side effects on mood, behavior and cognition seriously affect quality of life in children with acute lymphoblastic leukemia (ALL) during a long treatment period. Based on recent studies in animals, we hypothesized that these neuropsychological side effects are mediated by dexamethasone-induced cortisol depletion of the mineralocorticoid receptor (MR) in the brain. Therefore, we hypothesize that these side effects could be ameliorated by an intervention with hydrocortisone. For clinical application settings however, an absolute prerequisite is that MR activation does not interfere with the efficacy of the glucocorticoids, dexamethasone and prednisolone, on ALL cells. Materials and Methods: To investigate responsiveness of leukemic cell lines and fresh patients’ leukemic cells to dexamethasone and prednisolone in the presence of hydrocortisone, MTT-assays were performed. In addition MR and the glucocorticoid receptor (GR) expression on leukemic cells of different ALL subtypes was studied with a microarray-based gene expression profiling and validated by quantitative real-time PCR. Results: Leukemic cells expressed the MR at a very low level with a significantly higher (P≤0.001) expression in ETV6-RUNX1+ patients (median: 160.7 [AU] of fluorescence intensity, range: 38.1 - 760.6 [AU]) versus other ALL subtypes (median: 41.8 [AU] of fluorescence intensity, range: 25.1 - 276.2 [AU]). MR expression did not differ between glucocorticoid resistant and sensitive patients’ cells. Hydrocortisone addition did not affect glucocorticoid sensitivity of leukemic cell lines and patients’ leukemic cells of different leukemic subtypes also including ETV6-RUNX1+. Glucocorticoid sensitive patients’ cells became significantly more sensitive by hydrocortisone addition (prednisolone: P≤0.01, dexamethasone: P≤0.05). Conclusion: This present study shows that hydrocortisone does not interfere with efficacy of dexamethasone and prednisolone in vitro. These findings support a clinical randomized trial to study whether addition of hydrocortisone decreases the neuropsychological side effects of dexamethasone in children with ALL. Acknowledgments: The financial support of the KiKa® (Kinderen Kankervrij) foundation is highly appreciated. Disclosures No relevant conflicts of interest to declare.

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