Anti-Leukemia Activity of the Selective BCL-2 Inhibitor ABT-199 in Childhood B-Cell Precursor Acute Lymphoblastic Leukemia Is Characterized By MCL-1/BCL-2 Expression Serving As Biomarker for Treatment Response

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1081-1081
Author(s):  
Felix Seyfried ◽  
Salih Demir ◽  
Rebecca Hörl ◽  
Stefan Köhrer ◽  
Annika Scheffold ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
Cell Lines ◽  
Research Funding ◽  
Lymphoblastic Leukemia ◽  
High Ratio ◽  
Cell Precursor ◽  
Free Survival ◽  
Ic50 Values

Abstract Despite superior outcome and survival of patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), relapse occurs in 10-20% and is associated with poor outcome, clearly indicating future challenges including reduction of relapse rates and effective treatment of reoccurred leukemia. Deficiencies in cell death and survival pathways have been implicated in therapy failure and treatment resistance in BCP-ALL. Members of the BCL-2 family are key regulators of these pathways and are therefore of interest as therapeutic targets. The small molecule ABT-199 binds selectively to BCL-2, inhibits its anti-apoptotic function and leads to release of pro-apoptotic molecules. Recently, ABT-199 has demonstrated clinical activity, particularly in poor prognosis CLL. However, insensitivity and resistance in different cases clearly emphasize the need of predictive markers for upfront identification of ABT-199 responsive leukemias. Here, we analyzed sensitivity for ABT-199 in a series of individual BCP-ALL samples, addressed mechanisms of resistance and evaluated markers indicating response to ABT-199. Anti-leukemic activities of ABT-199 were investigated in BCP-ALL cell lines (n=6) and patient-derived BCP-ALL primograft samples (n=17), which were established by transplantation of primary patient ALL cells obtained at diagnosis onto NOD/SCID mice. Half maximal inhibitory concentrations (IC50) for ABT-199 were analyzed for each sample. Expression of apoptosis regulating molecules was investigated by western blot analysis and associated with ABT-199 responsiveness. Two MCL-1 deficient ALL cell lines were generated by CRISPR/Cas9 gene editing. Leukemia free-survival of ALL bearing animals was analyzed after in vivoABT-199 treatment. The majority of BCP-ALL samples showed sensitivity for ABT-199 induced cell death in the nanomolar range, both in cell lines (n=4, IC50: 29 - 422 nM) and patient-derived primograft samples (n=10, IC50: 1.7 - 74 nM), while 2 cell lines and 7 primograft leukemias showed insensitivity with IC50 values above 1 µM. ABT-199 binds directly to BCL-2 and upon binding, pro-apoptotic Bcl-2 family molecules like Bim are dislocated from BCL-2 and induce apoptosis. The anti-apoptotic BCL-2 family member MCL-1 is not bound by ABT-199, but sequesters pro-apoptotic molecules dislocated from BCL-2 leading to interruption of apoptosis induction. Therefore, we addressed expression levels of BCL-2 and MCL-1. We found high BCL-2 levels in ABT-199 sensitive and low BCL-2 levels in resistant leukemia samples and an opposite pattern for MCL-1 (high in resistant and low MCL-1 in sensitive ALL), in line with previous reports. Most interestingly, a high ratio of MCL-1 to BCL-2 expression (high MCL-1, low BCL-2) was significantly associated with high IC50 values/resistance (Spearman Rho correlation, p= .01), whereas a low MCL-1/BCL-2 ratio indicated ABT-199 sensitivity. Two of the 6 cell lines showed ABT-199 resistance (IC50 > 1 µM) and high Mcl-1 expression. Effective MCL-1 knock-out in both cell lines led to a clear sensitization for ABT-199 with up to 40-fold reduced IC50 values, clearly indicating MCL-1 as a key mediator of ABT-199 resistance in BCP-ALL. Finally, we also evaluated the anti-leukemia activity of ABT-199 in a preclinical setting in vivo. Two patient-derived leukemias, one with a low MCL-1/BCL-2 ratio of 0.9 and the other with a high ratio of 16.1, indicative of ABT-199 sensitivity or resistance, were transplanted onto NOD/SCID mice and treated with ABT-199 for 10 days after ALL engraftment. Most interestingly, a significantly increased leukemia free survival was observed in ABT-199 as compared to vehicle treated recipients (p<0.001) of the leukemia with the low MCL-1/BCL-2 ratio, in contrast to similar survival times of vehicle or ABT-199 treated animals bearing the high MCL-1/BCL-2 ratio ALL, clearly showing the predictive value of BCL-2 and MCL-1 levels in BCP-ALL. Taken together, ABT-199 shows anti-leukemia activity in the majority of BCP-ALL samples, with a strong association of high BCL-2 and low MCL-1 levels with ABT-199 sensitivity. Silencing of MCL-1 clearly revealed a crucial role for MCL-1 as mediator of ABT-199 resistance. Importantly, in vivo evaluation of ABT-199 in a preclinical setting highlighted the predictive value of BCL-2/MCL-1 expression for the identification of patients who would benefit from future BCL-2 directed therapies. Disclosures Stilgenbauer: Genzyme: Consultancy, Honoraria, Other: Travel grants , Research Funding; Genentech: Consultancy, Honoraria, Other: Travel grants , Research Funding; Janssen: Consultancy, Honoraria, Other: Travel grants , Research Funding; Sanofi: Consultancy, Honoraria, Other: Travel grants , Research Funding; Hoffmann-La Roche: Consultancy, Honoraria, Other: Travel grants , Research Funding; Novartis: Consultancy, Honoraria, Other: Travel grants , Research Funding; GSK: Consultancy, Honoraria, Other: Travel grants , Research Funding; Gilead: Consultancy, Honoraria, Other: Travel grants , Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel grants , Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel grants, Research Funding; Mundipharma: Consultancy, Honoraria, Other: Travel grants , Research Funding; Celgene: Consultancy, Honoraria, Other: Travel grants , Research Funding; Amgen: Consultancy, Honoraria, Other: Travel grants, Research Funding; Boehringer Ingelheim: Consultancy, Honoraria, Other: Travel grants , Research Funding.

scholarly journals FOXO1 Is Involved in the Regulation of B-Cell Precursor Acute Lymphoblastic Leukemia Survival and Serves As a Novel Target for Directed Therapy

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4020-4020
Author(s):  
Salih Demir ◽  
Fan Wang ◽  
Franziska Gehringer ◽  
Clarissa Weitzer ◽  
Klaus-Michael Debatin ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
High Risk ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Cell Precursor ◽  
Free Survival

Abstract Acute lymphoblastic leukemia (ALL) is the most common pediatric and adolescent malignancy. Although current treatment provides five-year event-free survival, in up to 20% conventional chemotherapy fails resulting in relapse with inferior prognosis. FOXO1 is a member of the forkhead family of transcription factors, which is preferably expressed in B-cells with high expression at the early B-cell stage. FOXOs are involved in several cellular processes including cell death and proliferation, anti-cancer drug resistance and protection from oxidative stress. Since FOXO1 can enhance tumor growth and potentiate metastasis, we aimed to investigate the effects of FOXO1 inactivation on B-cell precursor (BCP)-ALL, including preclinical in vivo evaluation. FOXO1 expression levels were compared among 497 cancer samples using the Genevestigator online software. Expression of FOXO1 in BCP-ALL was significantly higher than in any of the other cancer types. Next, we investigated FOXO1 expression and subcellular localization in 3 BCP-ALL cell lines by cellular fractionation and fluorescent microscopy. Both methods showed localization of FOXO1 in the nucleus, indicating transcriptionally active FOXO1 in BCP-ALL. In order to study the potential anti-tumor effect of FOXO1 repression, we investigated genetically modified, FOXO1 deficient BCP-ALL cell lines (n=5) and observed no cell death induction in control transduced cells, in contrast to a clear reduction of cell viability of up to 80% upon FOXO1 knock-down, clearly indicating dependency of BCP-ALL cells on FOXO1. Moreover, lentiviral mediated FOXO1 knockdown did not induce cell death in the Hodgkin's lymphoma cell line cHL, suggesting a BCP-ALL specific importance for FOXO1. Based on these results indicating the importance of FOXO1 expression for BCP-ALL maintenance, we investigated the feasibility of pharmacological interference with FOXO1. Exposure of 7 BCP-ALL, 4 T-ALL, 3 B-cell NHL, 2 DLBCL and 3 cHL cell lines to the small molecular weight FOXO1 inhibitor AS1842856 showed effectivity in BCP-ALL lines, reflected by significantly higher half maximal inhibitory concentrations (IC50) by MTT test. The most sensitive cell line was the BCP-ALL line RS4;11, while the cHL cell line SUP-HD1 showed insensitivity for FOXO1 inhibition (IC50: 3 nM and 26 µM), again indicating that BCP-ALL is particularly dependent on FOXO1 activity. Caspase 3 cleavage detected upon exposure to AS1842856 showed induction of apoptosis as mechanism of cell death. Furthermore, we evaluated the sensitivity of primary BCP-ALL primograft samples (n=9) exposing the ALL cells to increasing pharmacologically relevant concentrations of AS1842856. The inhibitor increased cell death as measured by flow cytometry (FSC/SSC criteria) in all of the samples tested in a time and dose dependent manner. Importantly, FOXO1 inhibition also showed activity on high risk leukemias including MLL-rearranged and early or second-relapse cases. Moreover, we investigated the in vivo effectivity of AS1842856. Two different patient derived leukemias were transplanted onto NOD/SCID mice and upon leukemia manifestation vehicle or AS1842856 was administered for a time of 11 days. At the end of the experiment, all mice were sacrificed and tumor loads were quantified in spleen, bone marrow and central nervous system (CNS). Importantly, tumor loads of all compartments and spleen sizes were significantly reduced in AS1842856 treated animals (p=0.028, U-test). Moreover, in an early-relapse sample leukemia-free survival upon AS1842856 treatment was evaluated. Mice were treated by vehicle or AS1842856 (n=10/group) during 11 days. Leukemia-free survival was significantly prolonged in mice which received AS1842856 (p=0.003, Log-rank test). Taken together, we show that the active form of FOXO1 is highly expressed in BCP-ALL cells as compared to other cancers, and that viability of BCP-ALL cells is regulated by FOXO1 activity. Importantly, silencing or pharmacological inhibition of FOXO1 induces cell death in BCP-ALL primogafts including high risk cases, both ex vivo and preclinically in vivo. Thus, targeting FOXO1 provides a promising novel strategy for therapeutic intervention in these high-risk subtypes of BCP-ALL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Synergistic Activity of the MCL-1-Specific Inhibitor S63845 with Venetoclax in B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1416-1416
Author(s):  
Felix Seyfried ◽  
Felix Stirnweiß ◽  
Stefan Köhrer ◽  
Klaus-Michael Debatin ◽  
Lüder Hinrich Meyer
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
High Risk ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Specific Inhibitor ◽  
Synergistic Activity ◽  
Cell Precursor

Abstract Deregulated cell death and survival pathways contribute to leukemogenesis and treatment failure of B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients. The intrinsic apoptosis pathway is regulated at the mitochondrial level by different pro- and anti-apoptotic molecules. Members of the BCL-2 family are key regulators of mitochondrial apoptosis signaling. Pro-apoptotic BH3-only proteins like BIM and BID activate pro-death proteins such as BAX and BAK leading to cell death. Anti-apoptotic BCL-2 family members including BCL-2, BCL-XL and MCL-1 bind to and sequester pro-apoptotic molecules, prevent activation of pro-death proteins and counter-regulate apoptosis induction. Small molecule inhibitors have been developed that block binding to anti-apoptotic molecules like BCL-2, leading to release of pro-apoptotic proteins and cell death induction. In particular, the BCL-2-specific inhibitor venetoclax (VEN) has demonstrated substantial anti-cancer activity and became an approved drug for the treatment of CLL patients. Investigating different, individual BCP-ALL samples, we and others recently identified heterogeneous sensitivities for VEN, suggesting that BCP-ALL cells might also depend on other pro-survival BCL-2 family proteins including MCL-1, leading to VEN insensitivity and resistance. A novel BH3-mimetic, S63845, that selectively targets MCL-1 has been reported. Here, we assessed the activity of S63845 and addressed a potential synergism of simultaneous blockage of BCL-2 and MCL-1 by VEN and S63845 (S) in BCP-ALL. The activity of the MCL-1 inhibitor was analyzed in a panel of BCP-ALL cell lines (N=6) and a series of primary, patient-derived BCP-ALL primograft samples (N=27) determining half-maximal effective concentrations (EC50) upon exposure to increasing concentrations of S and analysis of cell death induction. We observed heterogeneous sensitivities to S with EC50 values ranging from 16 nM to almost 10 µM. Protein expression of MCL-1 and other BCL-2 family members BCL-2, BCL-XL and BCL-W was assessed by western blot analysis and quantified, however neither association of MCL-1 levels nor expression of the other regulators and S sensitivity was found in cell lines and primograft leukemias. Moreover, we also compared sensitivities for both inhibitors but found independent activities of S and VEN in individual ALL samples. Next, we addressed the role of MCL-1 for VEN sensitivity and generated two MCL-1 knock out BCP-ALL cell lines by CRISPR/Cas9 gene editing. In both lines, clearly increased VEN sensitivities were observed upon depletion of MCL-1, indicating that MCL-1 is contributing to activity of the BCL-2 inhibitor VEN. Based on these findings, we investigated the effects of pharmacological MCL-1 inhibition for VEN sensitivity and incubated all 6 cell lines with VEN and S at increasing concentrations and observed clear synergistic effects upon combined BCL-2 and MCL-1 inhibition indicated by combination indices (CI) below 0.1. Moreover, we investigated 7 primograft BCP-ALL samples and found that MCL-1 inhibition by S clearly synergized with VEN activity (CI < 0.3). To investigate the anti-leukemia activity of co-targeting BCL-2 and MCL-1 in vivo in a pre-clinical setting, a high-risk leukemia derived from an infant, MLL/ENL rearranged pro-B ALL case was transplanted onto NOD/SCID mice. Upon ALL manifestation (presence of >5% human blasts in blood), recipients were treated with either VEN, S, the combination of both, or vehicle for 10 days. After treatment, leukemia loads were analyzed showing significantly reduced loads in the co-treated group as compared to vehicle, VEN or S alone in spleen, bone marrow, and central nervous system (p-values < 0.05), indicating synergistic activity of co-inhibition of BCL-2 and MCL-1 in vivo. Taken together, our data show heterogeneous sensitivity of individual BCP-ALL samples to MCL-1 inhibition by S, which is not associated with MCL-1 protein expression levels or VEN sensitivity. Both, genetic depletion and inhibition of MCL-1 by S synergizes with VEN leading to increased anti-leukemia activity in vitro and ex vivo. Importantly, co-targeting BCL-2 and MCL-1 significantly reduced leukemia infiltration in spleen, BM and CNS in a pre-clinical model of high-risk BCP-ALL, warranting further evaluation and possible clinical application of targeting MCL-1 alone and in combination with BCL-2 inhibition. Disclosures No relevant conflicts of interest to declare.

scholarly journals Identification of Potent BH3-Mimetic Combinations Targeting Pro-Survival Pathways in Human B-Cell Acute Lymphoblastic Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 567-567
Author(s):  
Donia M Moujalled ◽  
Diane T Hanna ◽  
Giovanna Pomilio ◽  
Veronique Litalien ◽  
Shaun Fleming ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Advisory Committee ◽  
Cell Lines ◽  
Research Funding ◽  
Kinase Inhibitors ◽  
Lymphoblastic Leukemia ◽  
Bh3 Mimetics ◽  
Nsg Mice ◽  
Bh3 Mimetic

Abstract Background Precursor-B acute lymphoblastic leukemia (B-ALL) is an aggressive hematological malignancy. Relapsed disease has a poor prognosis, despite improved outcomes with tyrosine kinase inhibitors for Ph+ cases and immunotherapeutic approaches, such as blinotumomab and CAR-T cells. Targeting cell survival with novel small molecule BH3-mimetic inhibitors of BCL-2 (e.g. Souers et al Nat Med 2013, Roberts et al, NEJM 2016 and Casara et al, Oncotarget 2018), BCL-XL (Lessene et al, Nat Chem Biol, 2013) or MCL1 (Kotschy et al, Nature 2016) is an emerging therapeutic option. BCL-2 is reported to have a pro-survival role in BCR-ABL1, JAK2 fusion, ETV6-RUNX1 and MLL-r driven ALL (Brown et al., Journal Biological Chemistry 2017). BH3-mimetics targeting BCL-2 and BCL-XL has efficacy in paediatric ALL xenografts (Khaw et al., Blood 2016), while ruxolitinib combined with ABT-737 is synergistic in JAK2-mutant pre-B-ALL (Waibel et al., Cell Reports 2013). We now report that combined targeting of BCL-2 and MCL1 has broad pre-clinical efficacy in adult B-ALL samples with Ph+, Ph- and Ph-like characteristics. Methods S55746 and S63845 were obtained from Servier/Novartis, A1331852 from Guillaume Lessene (WEHI), venetoclax, daunorubicin, dexamethasone (DXM) and tyrosine kinase inhibitors (TKIs) from Selleckchem. Bliss synergy scores were determined using a checkerboard approach to evaluate combinations (previously described Bliss, Ann Appl Biol 1939). Primary ALL cells were obtained from 14 patients (4 Ph+ and 10 Ph-) providing informed consent. Ex vivo cell viability (sytox blue exclusion) at 48h was determined over a 5-log dilution range (1nM-10uM) using drugs alone or in equimolar combinations. For in vivo studies, adult B-ALL patient derived xenografts were performed in NSG; NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice. Results Dual BH3-mimetic targeting of BCL-2 and MCL1 was strongly synergistic (Bliss sum >1000) in SUPB15 (Ph+ BCR-ABL1), BV173 (lymphoid blast crisis BCR-ABL1), MUTZ5 (Ph-like) and MHHCALL4 (Ph-like) B-ALL cell lines. This was more effective than single BH3-mimetic combinations with DXM or TKIs (dasatinib or ruxolitinib) (Fig. A, B). In B-ALL patient samples, combined BCL-2 and MCL1 targeting lowered the LC50 by 10-1000 fold (to LC50<10nM) in 4/4 Ph+ ALL cases and 8/10 Ph- cases. Similarly, combined MCL1 and BCL-XL targeting demonstrated synergy in 3/4 Ph+ cases and 7/10 Ph- cases (to LC50<10nM), confirming remarkable anti-leukemic activity compared to BH3-mimetics alone or chemotherapy (daunorubicin) (Fig. C). BH3-mimetic combination therapy (S55746/S63845) compared favourably in Ph+ ALL cases to S55746 (figure D) or S63845 (Figure E) in combination with dasatinib. Preliminary data using patient-derived xenografts in NSG mice revealed in vivo efficacy of combined S55746 and S63845 therapy against 3 adult B-ALL cases (1 Ph+ and 2 Ph-). Reduction of established ALL in the bone marrow was observed in mice receiving combined S55746/S63845 after one week of treatment (p=<0.05) (Fig. F-H). Conclusions Dual BH3-mimetic targeting of BCL-2 and MCL1 induces synergistic killing of human B-ALL cell lines and primary ALL samples in vitro and rapid cytoreduction in vivo. Simultaneous inhibition of BCL-2 and MCL1 represents a novel and effective approach for targeting Ph+, Ph- and Ph-like B-ALL without need for additional DNA-damaging chemotherapy or kinase inhibition. Our results support the translational investigation of dual BH3-mimetic targeting of BCL-2 and MCL1 in the clinic. Figure legend: BLISS synergy scores for A. Ph+ and B. Ph-like ALL cell lines for drug combinations targeting BCL-2, MCL1, BCR-ABL, JAK1/2 and DXM. C. LC50 activity in primary ALL after 48hr of treatment with BH3 mimetics and combinations targeting BCL-2, MCL1, BCL-XL, compared to daunorubicin (LC50< 10nM red; ~ 100nM yellow; >1uM green). D. Comparison of BH3-mimetics targeting D.BCL-2 or E. MCL1 in combination with dasatinib in Ph+ vs Ph- primary B-ALL samples. Activity expressed as LC50 activity after 48h, with median values shown. Irradiated NSG mice were transplanted with 106 primary B-ALL cells. Engraftment of F. Ph+ and G-H. Ph- B-ALL cells was confirmed at 10 weeks by detection of hCD45 in PB. Mice were then treated with i) vehicle (d1-5), ii) S55746 100mg/kg days 1-5 by gavage, iii) S63845 25 mg/kg IV on days 2 and 4 or iv) S55746+S63845. Mice were euthanized on day 8 and hCD45+ from flushed femurs quantified. Disclosures Chanrion: Servier: Employment. Maragno:servier: Employment. Kraus-Berthier:servier: Employment. Lessene:servier: Research Funding. Roberts:Janssen: Research Funding; AbbVie: Research Funding; Genentech: Research Funding; Walter and Eliza Hall: Employment, Patents & Royalties: Employee of Walter and Eliza Hall Institute of Medical Research which receives milestone and royalty payments related to venetoclax. Geneste:servier: Employment. Wei:Pfizer: Honoraria, Other: Advisory committee; Celgene: Honoraria, Other: Advisory committee, Research Funding; Amgen: Honoraria, Other: Advisory committee, Research Funding; Servier: Consultancy, Honoraria, Other: Advisory committee, Research Funding; Novartis: Honoraria, Other: Advisory committee, Research Funding, Speakers Bureau; Abbvie: Honoraria, Other: Advisory board, Research Funding, Speakers Bureau.

Evaluation Of Sphingosine Kinase 1 As a Therapeutic Target In B-Lineage Acute Lymphoblastic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1426-1426
Author(s):  
Craig T Wallington-Beddoe ◽  
Stuart M Pitson ◽  
Jason A Powell ◽  
Kenneth F Bradstock ◽  
Linda J Bendall
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Chemotherapeutic Agents ◽  
Parp Cleavage ◽  
Signalling Pathways ◽  
Wide Range ◽  
Ic50 Values

Abstract Sphingosine 1-phosphate (S1P) is a bioactive lipid with roles in cell proliferation and survival. S1P is produced by the sphingosine kinases, SphK1 and SphK2. SphK1 is over-expressed in a number of malignancies and evidence points overwhelmingly to a pro-survival role. Furthermore, SphK1 has been shown to correlate with the clinical outcome of certain tumors. Here we focus on SphK1 as an important oncogenic target in acute lymphoblastic leukemia (ALL). We have previously shown SphK1 protein to be over-expressed and activated (Ser225 phosphorylation) in ALL cell lines and primary patient samples compared to normal CD34+CD19+ B-cell progenitors. Furthermore, we have reported the importance of SphK1 in the development of ALL by transducing B-cell progenitors isolated from WT or SphK1-/- mice with the ALL associated p185 form of the oncogenic fusion gene BCR/ABL and injecting transduced cells into sub-lethally irradiated WT mice. The absence of SphK1 significantly reduced the incidence of ALL in recipient mice (ASH 2012). Inhibition of SphK1 by the selective inhibitor SK1-I significantly reduced intra-cellular S1P concentrations (p=0.017 and p=0.003 at 24 and 48 hours respectively) in 3 cell lines examined, indicating that the drug targets this enzyme. SK1-I killed ALL cells as determined by annexin V/PI flow cytometric analysis with IC50 values ranging from 12 µM to 18 µM at 72 hours. Furthermore, SK1-I induced cell death in primary patient ALL cells by 16 hours. This agent resulted in virtually no caspase-3 cleavage and cell death was not prevented by the pan-caspase inhibitor Z-VAD-FMK (p=0.45, n=4). Marked cytoplasmic vacuolation was detected by light microscopy, with LC3 processing present by Western blot, consistent with the development of autophagy. However, the autophagy inhibitor 3MA failed to prevent SK1-I-mediated cell death. These results suggest that the cell death associated with inhibition of SphK1 in ALL cells is caspase-independent and cannot be attributed to autophagy. Surprisingly, conventional chemotherapeutic agents such as doxorubicin and vincristine failed to synergize with SK1-I, however, synergistic killing was observed when SK1-I was combined with 500 nM imatinib over 72 hours in Philadelphia-positive (BCR/ABL+) ALL cells. We have developed a novel SphK1 inhibitor, MP8, that targets the enzyme via a different mechanism to SK1-I, since it blocks ATP binding. MP8 reduced intra-cellular S1P in Jurkat cells by 43% compared to untreated controls, and killed Jurkat and SUP-B15 cells over 24 to 48 hours with IC50 values of 8 µM. Additionally, MP8 induced cell death in primary patient ALL cells by 24 hours. This agent resulted in classic apoptotic cell death, which was rescued by Bcl-2 over-expression, resulting in near complete reversal of PARP cleavage. SphK1 has indisputable tumor-promoting properties and lies downstream of a number of signalling pathways known to be dysregulated in ALL. Here we show that SphK1 is over-expressed and activated in ALL cells and targeting SphK1 has potent cytotoxic effects in a wide range of cell lines and patient samples. Furthermore, genetic deletion of Sphk1 significantly reduced the incidence of murine BCR/ABL-driven ALL. These findings suggest further examination of the role SphK1 plays in ALL will uncover novel interactions with oncogenic signalling pathways and paves the way for the inclusion of SphK1 inhibitors in future pre-clinical trials. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Identification of the Energy Stress Sensor AMPK As Therapeutic Target in Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2771-2771
Author(s):  
Lai N Chan ◽  
Jaewoong Lee ◽  
Kadriye Nehir Cosgun ◽  
Huimin Geng ◽  
Gang Xiao ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Lymphoblastic Leukemia ◽  
Cell Lineage ◽  
Glycolytic Activity ◽  
Novel Therapeutic

Abstract Background and Hypothesis: While often transformed by the same oncogenes, biological and clinical characteristics of B-cell lineage and myeloid leukemias markedly differ. For instance, BCR-ABL1 tyrosine kinase drives both chronic myeloid leukemia (CML) and B cell lineage Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). While the majority of CML patients achieve long-term disease-free survival under treatment, Ph+ ALL patients invariably relapse within months after initial remission. Here, we investigated whether the distinct characteristics of Ph+ ALL and CML have a metabolic basis and identified the metabolic sensor LKB1 and its substrate AMPK as novel therapeutic targets in pre-B ALL. Results: Metabolic measurements revealed strikingly higher AMP:ATP ratios with concomitant decreases in ATP production in patient-derived Ph+ ALL cells when compared to CML cells. These findings indicate a state of chronic energy depletion in pre-B ALL cells. Energy deficit activates the LKB1-AMPK energy sensor pathway to stimulate glucose uptake to restore ATP levels. Notably, LKB1 levels and activity of its substrate AMPKα were higher in patient-derived Ph+ ALL cells compared to CML cells. To study the consequences of inducible deletion of Lkb1, murine BCR-ABL1-driven myeloid lineage (CML) and B cell precursor (Ph+ ALL) Lkb1fl/fl leukemia cells were generated. We found that Lkb1-deletion increased glycolysis, ATP levels and proliferation in myeloid leukemia, consistent with the common notion that LKB1 is an established tumor suppressor. On the contrary, loss of Lkb1 function resulted in diminished glycolytic activity, impaired mitochondrial functions and cell death in pre-B ALL cells. C/EBPa-mediated reprogramming of B-cell into myeloid identity reversed the detrimental effects of Lkb1-deletion, restoring glycolysis, energy levels and survival of B→ myeloid reprogrammed cells. To study Lkb1 early in B cell lineage in vivo, Lkb1fl/fl mice were crossed with Mb1-Cretg/+ mice. Loss of Lkb1 function strikingly eradicated early B cell progenitor cells in vivo. Reduced survival fitness upon Lkb1 deletion in pre-B ALL cells was largely rescued by metabolites that can enter the TCA cycle and thus provide ATP. Importantly, we found that inducible deletion of Lkb1 delayed onset of pre-B ALL and prolonged survival of transplant recipient mice in vivo. Similar to observations made with deletion of Lkb1 in murine BCR-ABL1 pre-B ALL cells, both loss of Ampka function and small molecule inhibition of AMPK (BML-275) resulted in cell death as well as reduced glycolytic activity and mitochondrial function in BCR-ABL1 pre-B ALL cells. Moreover, prolonged overall survival was observed in transplant recipient mice injected with Ampka-deficient pre-B ALL cells. Finally, BML-275 synergized with glucocorticoids, a central component of all main therapy regimen in pre-B ALL, in eradicating patient-derived pre-B ALL cells. Conclusions: Taken together, our findings showed that B-cell lineage leukemia, unlike myeloid leukemia, critically depend on LKB1/AMPK signaling for survival. Our findings also showed that LKB1/AMPK can be leveraged to provide a novel therapeutic avenue in pre-B ALL. Disclosures Hochhaus: BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding.

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

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 280-280 ◽  
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.

scholarly journals AT1412, a Patient-Derived Antibody in Development for the Treatment of CD9 Positive Precursor B-Acute Lymphoblastic Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4461-4461
Author(s):  
Greta De Jong ◽  
Sophie E Levie ◽  
Remko Schotte ◽  
Wouter Pos ◽  
Daniel Go ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Melanoma Cells ◽  
Employment Equity ◽  
Equity Ownership

Despite rapid advances in immunotherapeutic options for precursor B-acute lymphoblastic leukemia (ALL), outcomes remain poor especially for adult ALL and relapsed pediatric ALL. With conventional chemotherapy, remission percentages in adult ALL range from 75 to 90%, but relapse rates are high and long-term leukemia-free survival ranges between 35-70% depending on age and risk group. The introduction of CD19 targeting immunotherapy has significantly improved patient outcomes in (relapsed) B-ALL. However, tumor escape via downregulation of CD19 occurs in a significant number of patients. Therefore an ongoing urgency remains for the identification of additional or alternative immunotherapeutic targets for the treatment of ALL. AT1412 is an antibody that was identified from the peripheral blood memory B cell pool of a patient cured of metastatic melanoma after adoptive T-cell therapy, using a B cell immortalization technology (AIMSelect) with ectopic Bcl-6 and Bcl-xL expression as described previously [Kwakkenbos et al. Nat. Med. 2010]. The antibody was selected based on differential binding to melanoma cells as compared to healthy melanocytes and was shown to be successful in killing melanoma cells in vitro and in vivo [manuscript submitted]. In addition to melanoma, AT1412 binds other tumor types including B-ALL, gastric, colon- and pancreatic cancer. The target of AT1412 is the tetraspanin CD9, which is expressed by more than half of all B-ALL. Expression of CD9 has been correlated with adverse prognosis [Liang et al. Cancer Biomark. 2018]. We assessed binding of this human CD9 antibody to a panel of ALL cell lines using flow cytometry. Binding of AT1412 to the B-ALL cell lines SUP-B15, MHH-CALL-2 and CCRF-SB varied as expected based on the CD9 levels that we detected using a commercial CD9 antibody. AT1412 induced antibody dependent cellular cytotoxicity (ADCC) on these cells, in line with the level of AT1412 binding. No binding was seen to the T-ALL cell line Jurkat. Importantly, these findings were confirmed in primary ALL samples, obtained prospectively at diagnosis from a cohort of patients with T- or B-ALL (n=30). AT1412 showed binding to 61% of B-ALL samples but not to T-ALL samples. The potential of AT1412 to induce ADCC was tested on patient samples from the same panel. Remarkably, AT1412 induced ADCC of all B-ALL samples it bound to (8 out of 14) and of none of the T-ALL samples. Cytotoxicity significantly correlated with the level of AT1412 binding. These findings were supported by the observation that AT1412 induced B-ALL cell death when a freshly drawn whole bone marrow sample from a patient with newly diagnosed B-ALL was cocultured with AT1412. AT1412-induced cell death of B-ALL blasts occurred without affecting the monocytic, granulocytic and lymphocytic populations. This cell death was not observed when this patient's ALL blasts were incubated with AML-targeting antibodies. Remarkably, AT1412 induced cell death in the absence of added effector cells or other (chemo)therapeutic agents, while the bone marrow sample contained over 80% blasts and as little as 3% lymphocytes. We are currently investigating the in vivo efficacy of the antibody in a humanized immune system mouse model with human B-ALL. Taken together, the majority of precursor B-ALL blasts express CD9 and expression of CD9 is associated with a dismal outcome. Our data demonstrate that CD9 can be successfully targeted by the human CD9 antibody AT1412, suggesting that AT1412 has the potential to be developed as a therapeutic antibody for B-ALL. AT1412 is currently being advanced through preclinical development. Disclosures De Jong: AIMM Therapeutics: Employment. Levie:AIMM Therapeutics: Employment. Schotte:AIMM Therapeutics: Employment, Equity Ownership, Patents & Royalties: Patent WO2017119811A1. Pos:AIMM Therapeutics: Patents & Royalties: Patent WO2017119811A1. Go:AIMM Therapeutics: Employment, Patents & Royalties: Patent WO2017119811A1. Yasuda:AIMM Therapeutics: Employment, Equity Ownership. Cercel:AIMM Therapeutics: Employment. van Hal-van Veen:AIMM Therapeutics: Employment. Frankin:AIMM Therapeutics: Employment. Villaudy:AIMM Therapeutics: Employment, Equity Ownership, Patents & Royalties: Patent WO2017119811A1. van Helden:AIMM Therapeutics: Employment, Equity Ownership, Patents & Royalties: Patent WO2017119811A1. van Eenennaam:AIMM Therapeutics: Employment. Spits:AIMM Therapeutics: Employment, Equity Ownership, Patents & Royalties: Patent WO2017119811A1. Hazenberg:AIMM Therapeutics: Other: Employment/equity of partner/spouse.

Vitamin K3 Selectively Induces Apoptosis in Acute Lymphoblastic Leukemia Cells with Constitutive Activation of IKKα/NF-kB Activation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 859-859
Author(s):  
Ningxi Zhu ◽  
Lubing Gu ◽  
Harry W. Findley ◽  
Kuang-Yueh Chiang ◽  
Muxiang Zhou
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
Cell Lines ◽  
Cytotoxic Effect ◽  
Human Cancer ◽  
Lymphoblastic Leukemia ◽  
Vitamin K3 ◽  
Neoplastic Cells

Abstract Although the cytotoxic effect of vitamin K3 (VK3) on human cancer cells has been repeatedly reported, no clear conclusions from either in vitro or in vivo tests have so far been made for VK3 as an anticancer agent due to marked inter-tumor variability of efficacy in response to VK3 treatment. Here, we report that sensitivity of neoplastic cells to VK3-induced killing depends on IKKα expression/NF-kB activation in the cells. We tested the sensitivity to VK3 of 14 leukemic cell lines established from children with acute lymphoblastic leukemia (ALL). The 14 lines were classified into three groups: IKKα +/NF-kB+, IKKα +/NF-kB−, IKKα−/NF-kB−. IKKα +/NFkB+ cell lines that are generally resistant to doxorubicin are more sensitive to VK3 induced cell death than are the IKKα +/NFkB− lines that are usually sensitive to doxorubicin. The median of IC 50 values of VK3 and doxorubicin as tested by WST analysis for IKKα +/NFkB+ cells were 3.92 mM and 1.58 mM, respectively, compared to IKKα +/NFkB− cells (7.3 mM of VK3 and 0.71 mM of doxorubicin, p&lt;0.01, t-test). Assays by testing activation of caspase and cleavage of death substrate PARP as well as flow cytometry showed that apoptosis was induced in a line with high levels of IKKα/NF-kB activation at 2 h after VK3 treatment. In contrast, apoptosis was not induced by VK3 even at 48 h post-treatment in two lines that lack IKKa expression and NF-kB activation. To test if IKKα/NF-kB is a molecular target of VK3 inducing apoptosis in ALL, we examined the expression and activation of IKKα/NF-kB in VK3-treated cells. VK3 specifically reduced IKKα expression and inhibited NF-kB activation, resulting in downregulation of NF-kB-mediated gene expression and apoptosis. These results suggest that inhibition of IKKα/NF-kB signaling pathway is essential for VK3 to induce cell death, and that VK3, a dietary factor with no cytotoxic effect on normal cells, would be a useful adjuvant in the treatment of ALL and other cancer patients whose neoplastic cells express constitutive NF-kB and are resistant to chemotherapy.

scholarly journals Association of relapse-linked ARID5B single nucleotide polymorphisms with drug resistance in B-cell precursor acute lymphoblastic leukemia cell lines

2020 ◽  
Author(s):  
MINORI TAMAI ◽  
Meixian Huang ◽  
Keiko Kagami ◽  
Masako Abe ◽  
Tamao Shinohara ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Lymphoblastic Leukemia ◽  
Cell Lines ◽  
Risk Allele ◽  
Lymphoblastic Leukemia ◽  
Chemotherapeutic Agents ◽  
Nucleotide Polymorphisms ◽  
Cell Precursor ◽  
Single Nucleotide ◽  
Ic50 Values

Abstract Background The genetic variants of the ARID5B gene have recently been reported to be associated with disease susceptibility and treatment outcome in childhood acute lymphoblastic leukemia (ALL). However, few studies have explored the association of ARID5B with sensitivities to chemotherapeutic agents. Methods We genotyped susceptibility-linked rs7923074 and rs10821936 as well as relapse-linked rs4948488, rs2893881, and rs6479778 of ARDI5B by direct sequencing of polymerase chain reaction (PCR) products in 72 B-cell precursor-ALL (BCP-ALL) cell lines established from Japanese patients. We also quantified their ARID5B expression levels by real-time reverse transcription PCR, and determined their 50% inhibitory concentration (IC50) values by alamarBlue assays in nine representative chemotherapeutic agents used for ALL treatment. Results No significant associations were observed in genotypes of the susceptibility-linked single nucleotide polymorphisms (SNPs) and the relapsed-linked SNPs with ARID5B gene expression levels. Of note, IC50 values of vincristine (VCR) (median IC50: 39.6 ng/ml) in 12 cell lines with homozygous genotype of risk allele (C) in the relapse-linked rs4948488 were significantly higher (p=0.031 in Mann–Whitney U test) than those (1.04 ng/ml) in 60 cell lines with heterozygous or homozygous genotypes of the non-risk allele (T). Furthermore, the IC50 values of mafosfamide [Maf; active metabolite of cyclophosphamide (CY)] and cytarabine (AraC) tended to be associated with the genotype of rs4948488. Similar associations were observed in genotypes of the relapse-linked rs2893881 and rs6479778, but not in those of the susceptibility-linked rs7923074 and rs10821936. In addition, the IC50 values of methotrexate (MTX) were significantly higher (p=0.023) in 36 cell lines with lower ARID5B gene expression (median IC50: 37.1 ng/ml) than those in the other 36 cell lines with higher expression (16.9 ng/ml). Conclusion These observations in 72 BCP-ALL cell lines suggested that the risk allele of the relapse-linked SNPs of ARID5B may be involved in a higher relapse rate because of resistance to chemotherapeutic agents such as VCR, CY, and AraC. In addition, lower ARID5B gene expression may be associated with MTX resistance.

scholarly journals Association of relapse-linked ARID5B single nucleotide polymorphisms with drug resistance in B-cell precursor acute lymphoblastic leukemia cell lines

2020 ◽  
Author(s):  
MINORI TAMAI ◽  
Meixian Huang ◽  
Keiko Kagami ◽  
Masako Abe ◽  
Shinpei Somazu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Lymphoblastic Leukemia ◽  
Cell Lines ◽  
Risk Allele ◽  
Lymphoblastic Leukemia ◽  
Chemotherapeutic Agents ◽  
Nucleotide Polymorphisms ◽  
Cell Precursor ◽  
Single Nucleotide ◽  
Ic50 Values

Abstract Background The genetic variants of the ARID5B gene have recently been reported to be associated with disease susceptibility and treatment outcome in childhood acute lymphoblastic leukemia (ALL). However, few studies have explored the association of ARID5B with sensitivities to chemotherapeutic agents. Methods We genotyped susceptibility-linked rs7923074 and rs10821936 as well as relapse-linked rs4948488, rs2893881, and rs6479778 of ARDI5B by direct sequencing of polymerase chain reaction (PCR) products in 72 B-cell precursor-ALL (BCP-ALL) cell lines established from Japanese patients. We also quantified their ARID5B expression levels by real-time reverse transcription PCR, and determined their 50% inhibitory concentration (IC50) values by alamarBlue assays in nine representative chemotherapeutic agents used for ALL treatment. Results No significant associations were observed in genotypes of the susceptibility-linked single nucleotide polymorphisms (SNPs) and the relapsed-linked SNPs with ARID5B gene expression levels. Of note, IC50 values of vincristine (VCR) (median IC50: 39.6 ng/ml) in 12 cell lines with homozygous genotype of risk allele (C) in the relapse-linked rs4948488 were significantly higher (p=0.031 in Mann–Whitney U test) than those (1.04 ng/ml) in 60 cell lines with heterozygous or homozygous genotypes of the non-risk allele (T). Furthermore, the IC50 values of mafosfamide [Maf; active metabolite of cyclophosphamide (CY)] and cytarabine (AraC) tended to be associated with the genotype of rs4948488. Similar associations were observed in genotypes of the relapse-linked rs2893881 and rs6479778, but not in those of the susceptibility-linked rs7923074 and rs10821936. In addition, the IC50 values of methotrexate (MTX) were significantly higher (p=0.023) in 36 cell lines with lower ARID5B gene expression (median IC50: 37.1 ng/ml) than those in the other 36 cell lines with higher expression (16.9 ng/ml). Conclusion These observations in 72 BCP-ALL cell lines suggested that the risk allele of the relapse-linked SNPs of ARID5B may be involved in a higher relapse rate because of resistance to chemotherapeutic agents such as VCR, CY, and AraC. In addition, lower ARID5B gene expression may be associated with MTX resistance.

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