A Precision Medicine Approach Incorporating Both Molecular and In Vitro Functional Data to Treat Patients with Relapsed/Refractory Acute Myeloid Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4043-4043
Author(s):  
Pamela S. Becker ◽  
Sylvia Chien ◽  
Timothy J Martins ◽  
Andrew Herstein ◽  
Cody Hammer ◽  
...  

Abstract Introduction: Acute myeloid leukemia (AML) is a heterogeneous disorder such that each patient exhibits a unique pattern of mutations. Nevertheless, standard treatment approaches are largely used for all patients with the exception of those with the PML-RARA translocation or FLT3 mutations. We are conducting a feasibility study, "Individualized Treatment for Relapsed/Refractory Acute Leukemia Based on Chemosensitivity and Genomics/Gene Expression Data" (NCT02551718). This abstract summarizes the results in the AML patients. . Methods: The primary objective of this trial is to test the feasibility of rapidly assessing patient cells using a high throughput assay for in vitro drug sensitivity with individual drugs and drug combinations and mutation profiling by next generation sequencing (NGS) of 194 genes (MyAML) to enable prompt initiation of optimal therapy. The secondary objective is to evaluate the response to the chosen therapy. The eligibility criteria include diagnosis of acute leukemia, age ≥ 3, relapsed after or refractory to 2 prior lines of therapy, ECOG ≤ 3, and adequate organ function. The high throughput screen (HTS) is performed at a core facility under CLIA. The custom Oncopanel1 contains 160 drugs and drug combinations, including FDA approved and investigational agents, targeted agents including kinase, mTOR, proteasome, HDAC and other inhibitors, and chemotherapy drugs including alkylators, purine analogs, topoisomerase inhibitors and others. Patient blood or marrow samples enriched for leukemia cells are analyzed for survival after a 72-hour exposure to 8 customized drug concentrations spanning 4 logs in duplicate in 384 well plates adherent to matrix protein. DNA and RNA are isolated from the same enriched cell fractions for NGS (MyAML) and RNAseq. MyAML analyzes genes at high depth, including breakpoint hotspot loci with optimized detection of large insertion and deletions and other structural variants found in AML. Results: Fourteen patients signed consent, and 11 AML patients were enrolled in the study to date. Seven patients had unfavorable and 4 intermediate cytogenetic risk. Four were primary refractory, 5 had antecedent hematologic disorder. The average number of prior regimens was 4 (range 2 to 6). Six patients had relapsed within ≤3 months after allogeneic transplant, prior to enrollment on this study. HTS results were obtained within an average of 5.5 days; mutation testing was obtained within an average of 13 days (range 9-17), return time after receipt at MyAML was on average 8 (range 7-12) days. Drug regimens were chosen within 1-2 weeks from testing. For 2 patients, treatment start was delayed by about one month to allow recovery from toxicity from prior therapy. For the other patients, treatment was initiated on average 7.8, median 8 (range 4-11) days from start of testing. Of 7 patients treated so far, the median overall survival was 171 days, range 70 to >289 days. Regimens chosen based on HTS results, mutation analysis, and ability to obtain FDA approved drugs off label included: bortezomib (B)/daunorubicin/cytarabine, romidepsin, B/azacitidine (Aza), B/idarubicin (2 patients),cladribine, omacetaxine (HHT) then HHT/cytarabine, B/Aza/sorafenib, gemcitabine, bortezomib, sorafenib. Mutation analysis revealed previously unknown potential targets in those patients, including ABL kinase, FLT3 ITD in 2 patients, and FLT3 TKD mutations that led to choice of treatment with imatinib, sorafenib, and investigational Flt3 inhibitor for 4 patients, respectively. Other potentially targetable mutations identified included IDH1/2, NRAS, KRAS, KIT, TP53, WT1, and others (Table). None of these very heavily pre-treated patients obtained a complete remission, but 3 remain alive > 1 yr post early relapse after allogeneic transplant. One patient's marrow exhibited decline in blasts from 82% to 24%, and all patients exhibited a decline in circulating blasts with the chosen treatments. Conclusion: This trial has proven that application of rapid molecular and functional screening to choice of treatment for patients with advanced acute myeloid leukemia is feasible. Direct comparison of this precision medicine approach to results obtained with standard trials is planned. These data and the responses and correlation with gene expression data will contribute to a future algorithm to optimize precision medicine approaches to leukemia therapy. Table Table. Disclosures Becker: JW Pharmaceutical: Research Funding; Millennium: Research Funding; Glycomimetics: Research Funding; Pfizer: Other: Scientific Steering Committee for a post marketing study; Amgen: Research Funding; CVS Caremark: Other: Accordant Health Services Medical Advisory Board; Abbvie: Research Funding; Invivoscribe: Honoraria. Patay:Invivoscribe, Inc: Consultancy. Carson:Invivoscribe, Inc: Employment. Radich:Novartis: Consultancy, Other: laboratory contract; Bristol-MyersSquibb: Consultancy; TwinStrand: Consultancy; ARIAD: Consultancy; Pfizer: Consultancy.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_2) ◽  
pp. LBA-4-LBA-4 ◽  
Author(s):  
Ilaria Iacobucci ◽  
Manja Meggendorfer ◽  
Niroshan Nadarajah ◽  
Stanley Pounds ◽  
Lei Shi ◽  
...  

CG Mullighan and T Haferlach: are co-senior authors Introduction: Recent genomic sequencing studies have advanced our understanding of the pathogenesis of myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and improved classification of specific subgroups. Unfortunately, these studies have mostly analyzed specific subtypes and/or used targeted DNA-sequencing, thus limiting discovery of novel mutational patterns and gene expression clusters. Here, we performed an integrated genome-wide mutational/transcriptomic analysis of a large cohort of adult AML and MDS samples to accurately define subtypes of diagnostic, prognostic and therapeutic relevance. Methods: We performed unbiased whole genome (WGS) and transcriptome sequencing (RNA-seq) of 1,304 adult individuals (598 AML and 706 MDS; Fig. 1A), incorporating analysis of somatic and presumed germline sequence mutations, chimeric fusions and structural complex variations. Transcriptomic gene expression data were processed by a rigorous bootstrap procedure to define gene expression subgroups in an unsupervised manner. Associations between genetic variants, gene expression groups and outcome were examined. Results: Genomic/transcriptome sequencing confirmed diagnosis according to WHO 2016 of AML with recurrent genetic abnormalities in 10.9% of cases. These cases had a distinct gene expression profile (Fig. 1A), good prognosis (Fig. 1B) and a combination of mutations in the following genes: KIT, ZBTB7A, ASXL2, RAD21, CSF3R and DNM2 in RUNX1-RUNXT1 leukemia; FLT3, DDX54, WT1 and CALR in PML-RARA promyelocytic leukemia; KIT and BCORL1 in CBFB-rearranged leukemia. In addition, 9% of cases showed rearrangements of KMT2A, with known (e.g. MLLT3) and non-canonical partners (e.g. ACACA, and NCBP1) and poor outcome. Although common targets of mutations have been previously described for myeloid malignancies, the heterogeneity and complexity of mutational patterns, their expression signature and outcome here described are novel. Gene expression analysis identified groups of AML and/or MDS lacking recurrent cytogenetic abnormalities (87%). The spectrum of the most frequently mutated genes (>10 cases) and associated gene expression subtypes is summarized in Figure 1A. TET2 (more frequent in MDS than AML, p=0.0011) and DNMT3A (more frequent in AML than MDS, p<0.0001) were the most frequently mutated genes. Interestingly, mutations in these genes promoting clonal hematopoiesis were significantly enriched in the subgroup with NPM1 mutations. Overall, NPM1 mutations occurred in 27.4% of AML and 1% of MDS and were characterized by four expression signatures with different combination of cooperating mutations in cohesin and signaling genes and outcome (Fig. 1C, gene expression, GE, groups 2, 3, 7 and 8). Co-occurring NPM1 and FLT3 mutations conferred poorer outcome compared to only NPM1, in contrast co-occurring mutations with cohesin genes had better outcome (Fig. 1D). Additional mutations that significantly co-occurred with NPM1 were in PTPN11, IDH1/2, RAD21 and SMC1A. Three gene expression clusters accounted for additional 9% of cases with mutual exclusive mutations in RUNX1,TP53 and CEBPA and co-occurring with a combination of mutations in DNA methylation, splicing and signaling genes (Fig. 1E, GE groups 4, 5 and 6). Interestingly, RUNX1 mutations were significantly associated with SRSF2 mutations but not with SF3B1, showed high expression of MN1 and poor outcome (Fig. 1F). In contrast to the distinct, mutation-associated patterns of gene expression in AML samples, the gene expression profile of MDS was less variable despite diversity in patterns of mutation. MDS was enriched in mutations of SF3B1 (27.2%), mutually exclusive with SFRS2 (14.4%) and U2AF1 (5.5%); TP53 (13.7%) and RUNX1 (10.5%) and a combination of mutations in epigenetic regulators with outcome dependent on mutational pattern (Fig. 1A, G-H). Moreover, structural variations and/or missense mutations of MECOM accounted for 2% of cases. Conclusions: the integration of mutational and expression data from a large cohort of adult pan myeloid leukemia cases enabled the definition of subtypes and constellations of mutations and have prognostic significance that transcends prior gene panel-based classification schema. Disclosures Meggendorfer: MLL Munich Leukemia Laboratory: Employment. Nadarajah:MLL Munich Leukemia Laboratory: Employment. Baer:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Mullighan:Illumina: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: sponsored travel; Pfizer: Honoraria, Other: speaker, sponsored travel, Research Funding; AbbVie: Research Funding; Loxo Oncology: Research Funding; Amgen: Honoraria, Other: speaker, sponsored travel. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1397-1397
Author(s):  
Diego Chacon ◽  
Ali Braytee ◽  
Yizhou Huang ◽  
Julie Thoms ◽  
Shruthi Subramanian ◽  
...  

Background: Acute myeloid leukemia (AML) is a highly heterogeneous malignancy and risk stratification based on genetic and clinical variables is standard practice. However, current models incorporating these factors accurately predict clinical outcomes for only 64-80% of patients and fail to provide clear treatment guidelines for patients with intermediate genetic risk. A plethora of prognostic gene expression signatures (PGES) have been proposed to improve outcome predictions but none of these have entered routine clinical practice and their role remains uncertain. Methods: To clarify clinical utility, we performed a systematic evaluation of eight highly-cited PGES i.e. Marcucci-7, Ng-17, Li-24, Herold-29, Eppert-LSCR-48, Metzeler-86, Eppert-HSCR-105, and Bullinger-133. We investigated their constituent genes, methodological frameworks and prognostic performance in four cohorts of non-FAB M3 AML patients (n= 1175). All patients received intensive anthracycline and cytarabine based chemotherapy and were part of studies conducted in the United States of America (TCGA), the Netherlands (HOVON) and Germany (AMLCG). Results: There was a minimal overlap of individual genes and component pathways between different PGES and their performance was inconsistent when applied across different patient cohorts. Concerningly, different PGES often assigned the same patient into opposing adverse- or favorable- risk groups (Figure 1A: Rand index analysis; RI=1 if all patients were assigned to equal risk groups and RI =0 if all patients were assigned to different risk groups). Differences in the underlying methodological framework of different PGES and the molecular heterogeneity between AMLs contributed to these low-fidelity risk assignments. However, all PGES consistently assigned a significant subset of patients into the same adverse- or favorable-risk groups (40%-70%; Figure 1B: Principal component analysis of the gene components from the eight tested PGES). These patients shared intrinsic and measurable transcriptome characteristics (Figure 1C: Hierarchical cluster analysis of the differentially expressed genes) and could be prospectively identified using a high-fidelity prediction algorithm (FPA). In the training set (i.e. from the HOVON), the FPA achieved an accuracy of ~80% (10-fold cross-validation) and an AUC of 0.79 (receiver-operating characteristics). High-fidelity patients were dichotomized into adverse- or favorable- risk groups with significant differences in overall survival (OS) by all eight PGES (Figure 1D) and low-fidelity patients by two of the eight PGES (Figure 1E). In the three independent test sets (i.e. form the TCGA and AMLCG), patients with predicted high-fidelity were consistently dichotomized into the same adverse- or favorable- risk groups with significant differences in OS by all eight PGES. However, in-line with our previous analysis, patients with predicted low-fidelity were dichotomized into opposing adverse- or favorable- risk groups by the eight tested PGES. Conclusion: With appropriate patient selection, existing PGES improve outcome predictions and could guide treatment recommendations for patients without accurate genetic risk predictions (~18-25%) and for those with intermediate genetic risk (~32-35%). Figure 1 Disclosures Hiddemann: Celgene: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Bayer: Research Funding; Vector Therapeutics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Metzeler:Celgene: Honoraria, Research Funding; Otsuka: Honoraria; Daiichi Sankyo: Honoraria. Pimanda:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Beck:Gilead: Research Funding.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1275-1275
Author(s):  
Sonja C Lück ◽  
Annika C Russ ◽  
Konstanze Döhner ◽  
Ursula Botzenhardt ◽  
Domagoj Vucic ◽  
...  

Abstract Abstract 1275 Poster Board I-297 Core binding factor (CBF) leukemias, characterized by translocations t(8;21) or inv(16)/t(16;16) targeting the core binding factor, constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, 40-50% of patients relapse, and the current classification system does not fully reflect the heterogeneity existing within the cytogenetic subgroups. Therefore, illuminating the biological mechanisms underlying these differences is important for an optimization of therapy. Previously, gene expression profiling (GEP) revealed two distinct CBF leukemia subgroups displaying significant outcome differences (Bullinger et al., Blood 2007). In order to further characterize these GEP defined CBF subgroups, we again used gene expression profiles to identify cell line models similar to the respective CBF cohorts. Treatment of these cell lines with cytarabine (araC) revealed a differential response to the drug as expected based on the expression patterns reflecting the CBF subgroups. In accordance, the cell lines resembling the inferior outcome CBF cohort (ME-1, MONO-MAC-1, OCI-AML2) were less sensitive to araC than those modeling the good prognostic subgroup (Kasumi-1, HEL, MV4-11). A previous gene set enrichment analysis had identified the pathways Caspase cascade in apoptosis and Role of mitochondria in apoptotic signaling among the most significant differentially regulated BioCarta pathways distinguishing the two CBF leukemia subgroups. Thus, we concluded that those pathways might be interesting targets for specific intervention, as deregulated apoptosis underlying the distinct subgroups should also result in a subgroup specific sensitivity to apoptotic stimuli. Therefore, we treated our model cell lines with the Smac mimetic BV6, which antagonizes inhibitor of apoptosis (IAP) proteins that are differentially expressed among our CBF cohorts. In general, sensitivity to BV6 treatment was higher in the cell lines corresponding to the subgroup with good outcome. Time-course experiments with the CBF leukemia cell line Kasumi-1 suggested a role for caspases in this response. Interestingly, combination treatment of araC and BV6 in Kasumi-1 showed a synergistic effect of these drugs, with the underlying mechanisms being currently further investigated. Based on the promising sensitivity to BV6 treatment in some cell lines, we next treated mononuclear cells (mostly leukemic blasts) derived from newly diagnosed AML patients with BV6 in vitro to evaluate BV6 potency in primary leukemia samples. Interestingly, in vitro BV6 treatment also discriminated AML cases into two distinct populations. Most patient samples were sensitive to BV6 monotherapy, but about one-third of cases were resistant even at higher BV6 dosage. GEP of BV6 sensitive patients (at 24h following either BV6 or DMSO treatment) provided insights into BV6-induced pathway alterations in the primary AML patient samples, which included apoptosis-related pathways. In contrast to the BV6 sensitive patients, GEP analyses of BV6 resistant cases revealed no differential regulation of apoptosis-related pathways in this cohort. These results provide evidence that targeting deregulated apoptosis pathways by Smac mimetics might represent a promising new therapeutic approach in AML and that GEP might be used to predict response to therapy, thereby enabling novel individual risk-adapted therapeutic approaches. Disclosures Vucic: Genentech, Inc.: Employment. Deshayes:Genentech, Inc.: Employment.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3456-3456 ◽  
Author(s):  
Ming-Yu Yang ◽  
Jan-Gowth Chang ◽  
Pai-Mei Lin ◽  
Jui-Feng Hsu ◽  
Cheng-Han Wu ◽  
...  

Abstract Abstract 3456 Studies in large-scale genome sequencing have shown that only 2% of the mammalian genome encodes mRNAs, but the most part is transcribed as long and short non-coding RNAs (ncRNAs). The ncRNAs with gene regulatory functions are starting to be seen as a common feature of mammalian gene regulation. Genomic imprinting is a form of epigenetic regulation and imprinted genes are silenced in a parental-specific manner. Imprinted genes tend to occur in clusters and ncRNAs have been found at all well-characterized imprinted clusters. Although the exact mechanism how imprinted ncRNA regulates gene expression remains largely unknown, it is general accepted that imprinted ncRNAs binds to chromatin modifying complexes, such as PRC2, TRX, and G9a, and generates specific silencing of genomic loci both in cis and trans. Imprinting is associated with many human diseases or syndromes (e.g. Prader-Willi, Angelman, Beckwith-Wiedemann, Retts, and Silver-Russell syndromes) and various cancers (e.g. breast, prostate, and colorectal cancers), but its role in leukemogenesis remain elusive. In this present study, a panel of 24 human imprinted ncRNAs genes, including ampd3, cpa4, snuf, rasgrf1, slc22a3, lgf2, treb3c, gabrb3, c15orf2, sfmbt2, rtl1, copg2, h19, l3mbtl, ppp1r9a, tspan32, lnpp5f, impact, nr3251, nr3252, znf215, prim2, peg3as and znf264, has been mined using Bioinformatics approach. We investigated the expression of these imprinted ncRNA genes using real-time quantitative RT-PCR in 67 newly-diagnosed acute myeloid leukemia patients with normal karyotypes (AML-NK), 22 AML patients with abnormal karyotypes (AML-AK), and 39 healthy individuals. In AML-NK patients, the expression of lgf2, h19, slc22a3, copg2, and impact were significantly upregulated than in healthy individuals (p < 0.0001). In AML-AK patients, besides lgf2, h19 and impact genes, ampd3 and gabrb3 were also significantly upregulated than in healthy individuals (p < 0.0001). Expression of igf2 was almost undetectable in healthy individuals but drastically increased in all AML patients. Both lgf2 and h19 were significantly increased in both AML-NK and AML-AK patients. From our preliminary results, it is reasonable to hypothesize that loss imprinting of lgf2/h19 is critical for the leukemogenesis of AML and under NK or AK conditions different additional ncRNAs are activated and affect different imprinted gene expression and thus leading to different clinical outcomes. Based on our findings, we will further perform methylation analysis of promoter CpG sites in AML patients to investigate if hypomethylation is responsible for the upregulation of these imprinted ncRNAs. We will also carry out in vitro functional analysis to elucidate the functions and mechanisms of these imprinted ncRNAs in AML tumorigenesis. Updated results of these analysis will be presented at the meeting. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2083-2083
Author(s):  
Bing Xu ◽  
Yuanfei Shi ◽  
Long Liu ◽  
Bing Z Carter

BCL-2 inhibition exerts effective pro-apoptotic activities in acute myeloid leukemia (AML) but clinical efficacy as a monotherapy was limited in part due to the treatment-induced MCL-1 increase. Triptolide (TPL) exhibits anti-tumor activities in part by upregulating pro-apoptotic BCL-2 proteins and decreasing MCL-1 expression in various malignant cells. We hypothesized that combined BCL-2 inhibition and TPL exert synergistic anti-leukemia activities and prevent the resistance to BCL-2 inhibition in AML. We here report that TPL combined with BCL-2 inhibitor ABT-199 synergistically induced apoptosis in leukemic cells regardless of p53 status through activating the intrinsic mitochondrial apoptotic pathway in vitro. Although ABT-199 or TPL alone inhibited AML growth in vivo, the combination therapy demonstrated a significantly stronger anti-leukemic effect. Mechanistically, TPL significantly upregulated BH3 only proteins including PUMA, NOXA, BID and BIM and decreased MCL-1 but upregulated BCL-2 expression in both p53 wild type and p53 mutant AML cell lines, while the combination decreased both BCL-2 and MCL-1 and further increased BH3 only BCL-2 proteins. MCL-1 and BCL-2 increases associated with respective ABT-199 and TPL treatment and resistance were also observed in vivo. Significantly downregulating MCL-1 and elevating BH3 only proteins by TPL could not only potentially block MCL-1-mediated resistance but also enhance anti-leukemic efficacy of ABT-199. Conversely, BCL-2 inhibition counteracted the potential resistance of TPL mediated by upregulation of BCL-2. The combination further amplified the effect, which likely contributed to the synthetic lethality. This mutual blockade of potential resistance provides a rational basis for the promising clinical application of TPL and BCL-2 inhibition in AML independent of p53 status. Disclosures Carter: Amgen: Research Funding; AstraZeneca: Research Funding; Ascentage: Research Funding.


2018 ◽  
Vol 1 (6) ◽  
pp. e201800153 ◽  
Author(s):  
Tanja Božić ◽  
Joana Frobel ◽  
Annamarija Raic ◽  
Fabio Ticconi ◽  
Chao-Chung Kuo ◽  
...  

De novo DNA methyltransferase 3A (DNMT3A) plays pivotal roles in hematopoietic differentiation. In this study, we followed the hypothesis that alternative splicing ofDNMT3Ahas characteristic epigenetic and functional sequels. SpecificDNMT3Atranscripts were either down-regulated or overexpressed in human hematopoietic stem and progenitor cells, and this resulted in complementary and transcript-specific DNA methylation and gene expression changes. Functional analysis indicated that, particularly, transcript 2 (coding for DNMT3A2) activates proliferation and induces loss of a primitive immunophenotype, whereas transcript 4 interferes with colony formation of the erythroid lineage. Notably, in acute myeloid leukemia expression of transcript 2 correlates with its in vitro DNA methylation and gene expression signatures and is associated with overall survival, indicating thatDNMT3Avariants also affect malignancies. Our results demonstrate that specificDNMT3Avariants have a distinct epigenetic and functional impact. Particularly, DNMT3A2 triggers hematopoietic differentiation and the corresponding signatures are reflected in acute myeloid leukemia.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3298-3298
Author(s):  
Lili Feng ◽  
Haohai Zhang ◽  
Paola de Andrade Mello ◽  
Dina Stroopinsky ◽  
Wenda Gao ◽  
...  

Abstract Corresponding author: Dr. Simon. C. Robson ([email protected]). Introduction: CD39/ENTPD1 (ectonucleoside triphosphate diphosphohydrolase-1) is the prototypic member of the GDA1-CD39 superfamily of ectonucleotidases and modulates purinergic signaling pathways. CD39 expression has been noted in human acute myeloid leukemia (AML) and likely contributes to chemoresistance [1]. Our study reported here elucidates the impact of Cd39 on engraftment and invasiveness of AML TIB-49 cells using an immunocompetent murine experimental model. Methods: Wild-type (WT) mice and Cd39 -/- mice on C57BL/6 background were bred at Beth Israel Deaconess Medical Center. The syngeneic murine AML cell line TIB-49 (Cd39 negative in vitro) was purchased from American Type Culture Collection. For bioluminescence imaging experiments, TIB-49 cells were transduced with luciferase/mCherry using a lentiviral vector. For AML model, mice were administered with 1×10 6 TIB-49-luciferase cells intravenously via tail vein injection. For chloroma model, mice were subcutaneously inoculated with 1×10 6 TIB-49 cells in the right flank. Bioluminescence imaging of TIB-49-luciferase bearing mice was conducted with the IVIS TM 50 Imaging System. Blood, spleen and bone marrow (BM) were also collected from TIB-49 bearing AML mice for FACS (fluorescence activated cell sorting) analysis. To explore Cd39 in TIB engraftment and invasiveness, TIB-49 cells were further transduced with a lentiviral vector overexpressing mCd39 with TdTomato. WT mice were intravenously inoculated with 1×10 6 of either TIB-49-TdTomato cells or TIB-49-mCd39-TdTomato cells, and the above read-outs were determined. To investigate the potential of CD39 as a therapeutic target, we engineered anti-mouse Cd39 antibodies (αCd39 mAb) with isotype selection and removal of fucose to further promote Fc receptor (FcR) interactions. Results: Bioluminescence imaging results indicated that TIB-49 engraftment was decreased in global Cd39 -/- mice with decreased disease burdens noted relative to WT (Figure 1A). FACS analysis of blood, spleen and BM-derived cells from TIB-49 bearing AML-model mice (day 31) confirmed higher engraftment of TIB-49 cells (TdTomato+) at all sites in WT compared to Cd39 -/- mice (Figure 1B). TIB-49 cells did not express Cd39 in vitro, but TIB-49 cells harvested from spleen and BM of WT but not Cd39 -/- mice displayed high levels of Cd39. This indicated TIB-49 cells acquired Cd39 from host cells, in a process of antibody-independent trogocytosis (Figure 1C), as RT-PCR did not detect Cd39 mRNA expression in TIB-49 cells in vivo. Additionally, circulating TIB-49 cells from the blood of WT mice were Cd39 negative (Figure 1C), suggesting a role for the tumor microenvironment in mediating trogocytosis. TIB-49 cells expressing host Cd39 in WT mice spleen and BM lost Cd39 after being exposed to αCd39 mAb treatment. Cd39 translocated from TIB-49 cells to effector cells, at least in part, dependent on FcR mediated trogocytosis (Figure 1D). When Cd39 was overexpressed on TIB-49 cells (TIB-49-mCd39-TdTomato), the engraftment was boosted in WT mice in vivo when compared to TIB-49-TdTomato cells (day 19, Figure 1E) with higher levels of Cd39 expression than that observed on TIB-49-TdTomato cells in spleen and BM (day 26) (Figure 1F). Moreover, TIB-49-mCd39-TdTomato bearing mice displayed shorter survival times, when compared with TIB-49-TdTomato bearing AML mice (Figure 1G). The αCd39 mAb monotherapy had no effect on TIB-49 chloroma model growth. However, pretreatment with αCd39 mAb effectively boosted daunorubicin chemotherapeutic effects in vivo (Figure 1H and 1I). Conclusions: Our study suggests bidirectional trogocytosis between TIB-49 AML and host immune cells, which is further modulated by FcR interaction. Re-distribution of Cd39 from host to TIB-49 cells or induced high level expression contributes to engraftment and invasiveness, resulting in decreased survival. Targeting CD39 is a potential therapeutic approach, operational not only by boosting chemosensitivity but furthering anti-leukemic effects in experimental models. Disclosures: No relevant conflicts of interest to declare. References: [1] Nesrine Aroua, Emeline Boet, Margherita Ghisi, et al. Extracellular ATP and CD39 Activate cAMP-Mediated Mitochondrial Stress Response to Promote Cytarabine Resistance in Acute Myeloid Leukemia. Cancer Discov. 2020. Figure 1 Figure 1. Disclosures Stroopinsky: The Blackstone Group: Consultancy. Avigan: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Kite Pharma: Consultancy, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Partner Tx: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Aviv MedTech Ltd: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Chugai: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Parexcel: Consultancy; Takeda: Consultancy; Sanofi: Consultancy.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1451-1451
Author(s):  
Sigal Tavor ◽  
Tali Shalit ◽  
Noa Chapal Ilani ◽  
Yoni Moskovitz ◽  
Nir Livnat ◽  
...  

Background: Recent advances in acute myeloid leukemia(AML) targeted therapy improve overall survival. While these targeted therapies can achieve prolonged remissions, most patients will eventually relapseunder therapy. Our recent studies suggest that relapse most often originates from several sub-clones of leukemic stem cells (LSCs), present before therapy initiation, and selected due to several resistance mechanisms. Eradication of these LSCs during treatment induction /remission could thus potentially prevent relapse. The overall goal of the current study was to identify drugs which can be safely administrated to patients at diagnosis and that will target LSCs. Since simultaneously testing multiple drugs in vivo is not feasible, we used an in vitrohigh throughput drug sensitivity assay to identify new targets in primary AML samples. Methods: Drug sensitivity and resistance testing (DSRT) was assessed in vitro (N=46 compounds) on primary AML samples from patients in complete remission (N=29). We performed whole exome sequencing and RNAseq on samples to identify correlations between molecular attributes and in vitro DSRT. Results:Unsupervised hierarchical clustering analysis of in vitro DSRT, measured by IC50, identified a subgroup of primary AML samples sensitive to various tyrosine kinase inhibitors (TKIs). In this subgroup, 52% (9/17) of AML samples displayed sensitivity to dasatinib (defined as a 10-fold decrease in IC50 compared to resistant samples). Dasatinib has broad TKI activity, and is safely administered in the treatment of leukemia. We therefore focused our analysis on predicting AML response to dasatinib, validating our results on the Beat AML cohort. Enrichment analysis of mutational variants in dasatinib-sensitive and resistant primary AML samples identified enrichment of FLT3/ITD (p=0.05) and PTPN11(p=0.05) mutations among dasatinib responders. Samples resistant to dasatinib were enriched with TP53 mutations (p=0.01). No global gene expression changes were observed between dasatinib-sensitive and resistant samples in our cohort, nor in the Beat AML cohort. Following this, we tested the differential expression of specific dasatinib-targeted genes between dasatinib-responding and resistant samples. No significant differences were identified. However, unsupervised hierarchical clustering of dasatinib targeted genes expression in our study and in the Beat AML cohort identified a subgroup of AML samples (enriched in dasatinib responders) that demonstrated overexpression of three SRC family tyrosine kinases:FGR, HCK and LYN as well as PTK6, CSK, GAK and EPHB2. Analysis of the PTPN11 mutant samples revealed that the IC50 for dasatinib in 23 carriers of the mutant PTPN11 was significantly lower compared to the IC50 of PTPN11 wild type samples (p=0.005). LYN was also upregulated (p&lt;0.001) in the mutant samples. We therefore hypothesized that gene expression of dasatinib-targeted genes could be used as a predictive biomarker of dasatinib response among FLT3/ITD carriers. We found that among FLT3/ITD AML carriers in the Beat AML cohort LYN, HCK, CSK and EPHB2 were significantly over-expressed in the dasatinib responding samples (N=27) as compared to the dasatinib resistant samples (N=35). To predict response to dasatinib among FLT3/ITD carriers we used a decision tree classifier based on the expression levels of these four genes. Our prediction model yielded a sensitivity of 74% and specificity of 83% for differentiating dasatinib responders from non-responders with an AUC of 0.84. Based on our findings, we selected FLT3/ITD AML samples and injected them to NSG-SGM3 mice. We found that in a subset of these samples, dasatinib significantly inhibited LSCs engraftment. This subset of FLT3/ITD AML samples expressed higher levels of LYN, HCK,FGR and SRC as compared to the FLT3/ITD samples that were not sensitive to dasatinib therapy in vivo. In summary, we identified a subgroup of AML patients sensitive to dasatinib, based on mutational and expression profiles. Dasatinib has anti-leukemic effects on both blasts and LSCs. Further clinical studies are needed to demonstrate whether selection of tyrosine kinase inhibitors, based on specific biomarkers, could indeed prevent relapse. Disclosures Tavor: Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS companies: Membership on an entity's Board of Directors or advisory committees.


Haematologica ◽  
2020 ◽  
Vol 105 (12) ◽  
pp. 2795-2804 ◽  
Author(s):  
Sigal Tavor ◽  
Tali Shalit ◽  
Noa Chapal Ilani ◽  
Yoni Moskovitz ◽  
Nir Livnat ◽  
...  

Novel targeted therapies demonstrate improved survival in specific subgroups (defined by genetic variants) of acute myeloid leukemia (AML) patients, validating the paradigm of molecularly targeted therapy. However, identifying correlations between AML molecular attributes and effective therapies is challenging. Recent advances in high-throughput in vitro drug sensitivity screening applied to primary AML blasts were used to uncover such correlations; however, these methods cannot predict the response of leukemic stem cells (LSCs). Our study aimed to predict in vitro response to targeted therapies, based on molecular markers, with subsequent validation in LSCs. We performed ex vivo sensitivity screening to 46 drugs on 29 primary AML samples at diagnosis or relapse. Using unsupervised hierarchical clustering analysis we identified group with sensitivity to several tyrosine kinase inhibitors (TKIs), including the multi-TKI, dasatinib, and searched for correlations between dasatinib response, exome sequencing and gene expression from our dataset and from the Beat AML dataset. Unsupervised hierarchical clustering analysis of gene expression resulted in clustering of dasatinib responders and non-responders. In vitro response to dasatinib could be predicted based on gene expression (AUC=0.78). Furthermore, mutations in FLT3/ITD and PTPN11 were enriched in the dasatinib sensitive samples as opposed to mutations in TP53 which were enriched in resistant samples. Based on these results, we selected FLT3/ITD AML samples and injected them to NSG-SGM3 mice. Our results demonstrate that in a subgroup of FLT3/ITD AML (4 out of 9) dasatinib significantly inhibits LSC engraftment. In summary we show that dasatinib has an anti-leukemic effect both on bulk blasts and, more importantly, LSCs from a subset of AML patients that can be identified based on mutational and expression profiles. Our data provide a rational basis for clinical trials of dasatinib in a molecularly selected subset of AML patients.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1312-1312
Author(s):  
Hanna Janke ◽  
Friederike Schneider ◽  
Daniela Schumacher ◽  
Tobias Herold ◽  
Hopfner Karl-Peter ◽  
...  

Abstract Background Internal tandem duplication (ITD) and pointmutations in the tyrosine kinase domain (TKD) of the receptor tyrosine kinase FLT3 occur in about 30% of patients with acute myeloid leukemia (AML). In contrast to the negative prognostic impact of FLT3-ITD in normal karyotype AML, FLT3 pointmutations occurring in the TKD and juxtamembrane (JM) region are less frequent and of unclear clinical impact. Although TKD mutations can induce resistance to tyrosine kinase inhibitors the individual transforming potential of FLT3 pointmutations has not been analysed in detail. In this study we have performed a comprehensive analysis of various FLT3 mutants in a comparative setting in vitro and analyzed gene expression profiles, and clinical outcome with respect to FLT3mutation status. Material and Methods We analyzed relapse and survival in 672 cytogenetically normal AML patients and the FLT3 status at diagnosis and relapse in 156 patients. In the murine Ba/F3 cell model we analyzed the transforming potential, subcellular localization, phosphorylation status and signaling properties of eight different FLT3 mutants. The investigated FLT3 mutations include three ITD of different length and insertion site, V592A in the JM region, common FLT3-TKD mutations D835V and D835Y as well as D839G and I867S in the second TKD. FLT3-D839G and -I867S were recently found in AML patients by our group during routine diagnostics but have not been functionally characterized before. The corresponding remission samples did not express these mutations. Further a gene expression profile analysis with respect to FLT3-ITD and -TKD mutation status and evaluation of differences in activation of predefined STAT5 target gene set was performed. Results In 672 normal karyotype AML patients FLT3-ITD, but not FLT3-TKD mutations were associated with an inferior relapse free and overall survival in multivariate analysis. In paired diagnosis-relapse samples FLT3-ITD showed higher stability (70%) compared to FLT3-TKD (30%). In vitro, FLT3-ITD induced a fully transformed phenotype in Ba/F3 cells, whereas FLT3 pointmutations showed a weaker but clearly transformed phenotype with gradual increase in proliferation and protection from apoptosis. The transforming capacity of the investigated mutants was associated with cell surface expression and tyrosine 591 phosphorylation of the FLT3 receptor. Western blot experiments revealed STAT5 activation only in FLT3-ITD transformed cells, further gene expression profile analyses displayed differences in predefined STAT5 target genes between FLT3-ITD and FLT3-TKD mutations. In contrast, FLT3-non-ITD mutants had an enhanced signal of AKT and MAPK activation. Further differences were found on mRNA level presenting deregulation of SOCS2, ENPP2, PRUNE2 and ART3 expression between FLT3-ITD, FLT3-TKD and FLT3-WT. Conclusion Although apparently divergent in response to treatment all functionally characterized mutants showed a clear gain-of-function phenotype with a wide range of transforming activity associated with clinical prognosis and signaling. Disclosures: No relevant conflicts of interest to declare.


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