bluuebunny/crossref_metadata_2025 huggingface dataset:
Therapeutic Targeting of the Histone Ubiquitination-Methylation Axis in T Cell Leukemia
Authors: Ntziachristos Panagiotis , Arcipowski Kelly , Martinez Carlos Alberto , Zhu Yixing , Volk Andrew G. , Kumar Suresh , Thomas Paul M , Van Vlierberghe Pieter , Hijiya Nobuko , Marshall Stacy , Wang Jack , Wu Jian , Kelleher Neil L , Crispino John
Published: October 2019

Acute lymphoblastic leukemia (ALL) is a highly aggressive blood cancer affecting children and adults. Certain high-risk disease subsets have poor outcomes and often debilitating therapy-related toxicities stemming from direct inhibition of the oncogenes. We hypothesize that the process of oncogenic transformation is driven by aberrant activity of oncogene-associated chromatin modifying partners. These changes create a chromatin environment unique to the malignant state and, therefore, disruption of critical oncogenic chromatin signatures would not likely affect healthy tissues. We have generated strong evidence for the intertwined roles between the NOTCH1 oncogenic pathway and deubiquitinase enzymes in T cell leukemia, members of the ubiquitin-specific proteases (USP) family in particular. Members of the USP family physically interact with NOTCH1 and the lysine 27 on histone H3 (H3K27) demethylase JMJD3 and this methylation-ubiquitination biology-related axis coordinates regulation of transcriptional initiation and elongation, vital for the survival of leukemia cells. Interestingly transcription of USP genes is positively controlled by NOTCH1 creating a feedback loop in leukemia.

We have further characterized this oncogenic axis using a combination of small molecule inhibitors and genetic engineering of USPs in ALL cell lines, primary patient samples and primagraft models of disease. We are able to show that a) USP activity is important for certain oncogenic pathways (such as NOTCH1) in leukemia; b) Oncogenes and USP enzymes co-bind certain areas in the leukemia genome; c) Ubiquitination of histone H2B acts in a combinatorial fashion with H3K27me, is a major epigenetic change affected by the USP activity in leukemia and controls d) transcriptional elongation. Finally we demonstrate that f) chemical inhibition or down-regulation of USPs affect leukemia growth in vitro and in vivo. Ongoing and future studies include manipulation of USP levels in mouse models of leukemia as well as combinatorial use of USP inhibitors with chemotherapeutic regiments in vitro using matched diagnosis-relapsed primary samples and in xenograft studies.

Information gained from these studies will lend rationale towards the use of small molecule inhibitors against USP proteins in clinical trials for the treatment of aggressive and relapsed ALL.

Disclosures

Kumar: Progenra Inc.: Employment. Wang:Progenra Inc.: Employment. Wu:Progenra Inc.: Employment.
The miRNA-193 Family Is a Potent Tumor-Suppressor and a Biomarker for Poor Prognosis in Acute Myeloid Leukemia
Authors: Jammal Razan , Krowiorz Kathrin , Haetscher Nadine , Emmrich Stephan , Rouhi Arefeh , Heuser Michael , Bothur Sabrina , Bullinger Lars , Döhner Konstanze , Lai Courteney , Maetzig Tobias , Obulkasim Askar , Martins Vera , Mulaw Medhanie A. , Stary Jan , Baruchel Andre , De Haas Valerie , Reinhardt Dirk , Döhner Hartmut , Ruschmann Jens , Zwaan Michel , van den Heuvel-Eibrink Marry , Heckl Dirk , Fornerod Maarten , Humphries R. Keith , Rieger Michael A , Kuchenbauer Florian , Klusmann Jan-Henning
Published: October 2019

Deregulated microRNA (miRNA) expression has been implicated in the pathogenesis of acute myeloid leukemia (AML). We previously showed that miR-193b is a STAT5-regulated miRNA that controls hematopoietic stem and progenitor cell (HSPC) expansion by modulating cytokine receptor signaling. Here we demonstrate that the miR-193 family members miR-193a and 193b are potent tumor suppressors in AML. Both miRNAs were downregulated in several cytogenetically-defined subgroups of pediatric and adult AML (n=202), whereas low miR-193b expression was an independent indicator for poor prognosis and survival. Accordingly, ectopic retroviral Hoxa9-Meis1 expression in HSPCs from miR-193b-/- mice resulted in a more aggressive disease with significantly shortened latency and survival as compared to miR-193bWT/WT HSPCs. Inversely, ectopic miR-193 expression in leukemic cells belonging to various AML subgroups decreased leukemic growth in vitro and prolonged survival of mice suffering from Hoxa9-Meis1-induced leukemia through a G1/S phase block. These effects were mediated by targeting c-KIT, KRAS and SOS2 - key factors of the KIT-RAS-RAF-MEK-ERK signaling cascade - as well as the downstream cell cycle regulator CCND1. Knockdown of each of these genes partially recapitulated the anti-proliferative effect of ectopic lentiviral miR-193 expression. As the tumor suppressive function is independent of patient age or AML cytogenetic background, these observations suggest an opportunistic role for miR-193 in future AML therapies. With the notion that a single miRNA can control aberrant MAPK signaling at multiple levels, restoring miR-193 expression in AML cells with constitutive activation of this cascade would assure high antileukemic efficacy, while avoiding the fast development of resistance mechanisms.

Disclosures

Heuser: Bayer Pharma AG: Research Funding; Novartis: Consultancy, Research Funding; BerGenBio: Research Funding; Tetralogic: Research Funding; Karyopharm Therapeutics Inc: Research Funding; Celgene: Honoraria; Pfizer: Research Funding. Mulaw:NuGEN: Honoraria. Baruchel:Jazz: Consultancy; Servier: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Baxalta: Research Funding.
Microrna-494 Activation Suppresses Bone Marrow Stromal Cell-Mediated Drug Resistance in Acute Myeloid Leukemia Cells
Authors: Tian Chen , Zheng Guoguang , You M. James , Zhang Yizhuo
Published: October 2019

Acute myeloid leukemia (AML) is not sensitive to chemotherapy partially because of the protection of AML cells by mesenchymal stromal cells (MSCs). Our previous studies found that MSCs protected AML cells from apoptosis through the c-Myc-dependent pathway. However, the mechanism by which MSCs regulate c-Myc in AML cells is still unknown. To elucidate the mechanism, we performed microRNA array analysis of AML cell lines and validated by TaqMan realtime PCR. The results showed that the expression of microRNA-494 (miR-494) in AML cells after coculture with MSCs was down-regulated. Reporter gene analysis confirmed miR-494 as one of the regulators of c-Myc. In the coculture system, activation of miR-494 in AML cells suppressed proliferation and induced apoptosis of AML cells in vitro. After addition of mitoxantrone to the coculture system, the proliferation of AML cells with miR-494 activation was suppressed more than that of control cells. After subcutaneous injection of AML cell lines in combination with MSC, tumor growth was suppressed in mice injected with miR-494-overexpressing AML cells. The rate of tumor formation was even lower after mitoxantrone treatment in the miR-494 overexpressing group. Moreover, miR-494 activation resulted in a decrease of leukemic cell counts in peripheral blood and bone marrow and prolonged survival in mice injected with miR-494-overexpressing AML cellls and MSCs compared to the control mice. Our results indicate that miR-494 suppresses drug resistance in AML cells by down-regulating c-Myc through interaction with MSCs and that miR-494 therefore is a potential therapeutic target.

Disclosures

No relevant conflicts of interest to declare.
Altered Expression of Immune Checkpoint Molecules Including Programmed Cell Death-1 (PD-1) and Its Ligands PD-L1/PD-L2 in Waldenstrom's Macroglobulinemia
Authors: Jalali Shahrzad , Price-Troska Tammy , Novak Anne J. , Ansell Stephen M
Published: October 2019

Waldenstrom's Macroglobulinemia (WM) is an indolent B-cell malignancy that is characterized by bone marrow infiltration of lymphoplasmacytic cells and excessive synthesis of IgM. Despite improved treatment strategies and increased understanding of the underlying molecular mechanisms contributing to malignant disease progression, WM remains incurable. While whole exome sequencing analysis has revealed the genomic events associated with malignant B cell transformation in WM, the bone marrow (BM) microenvironment is also emerging as a major player in the pathogenesis of WM. Previously, our lab has reported that an array of cytokines, including IL-21 and IL-6 are increased in the WM BM and such increases are associated with high proliferation rates and IgM secretion by WM cells. In this study, we aimed to identify how immune checkpoint molecules in the BM microenvironment, specifically programmed cell death-1 (PD-1) and its ligands PD-L1 and PD-L2, contribute to malignant cell expansion in WM.

Using Real-Time PCR analysis, we show that the expression of PD-1, PD-L1 and PD-L2 are all significantly elevated in the cells of WM BM as compared to their normal BM counterparts. Interestingly, PD-L1 expression is also upregulated in the malignant WM cells. These findings were further confirmed by flow cytometry analysis. Subsequent in vitro analysis showed that PD-L1 and PD-L2 are cleaved from the WM cells and these soluble ligands (sPD-L1 and sPD-L2) are able to bind to the cells in the BM microenvironment, including T-cells. This results in reduced activation and proliferation of T-cells, and is accompanied by a reduction in cyclin A and p-ERK levels. In validation of the in vitro data, we also found sPD-L1 and sPD-L2 in the bone marrow plasma obtained from WM patients. While sPD-L2 was found to be present in both WM and normal BM plasma (though in a reduced level in WM), sPD-L1 was exclusive to the WM samples, implying that the function of these molecules are differentially regulated in WM. Furthermore, overexpression of PD-L1 in a WM cell line, MWCL.1, resulted in an increase in IgM secretion. Interestingly, treatment with IL-21 increased the expression of PD-L1 in WM cells, indicating that elevated IL-21 in WM BM could contribute to increased expression of PD-L1 by malignant WM cells.

In summary, our data support a role for PD-1 ligands as immune regulatory molecules in WM. Further studies are ongoing to explore the molecular mechanisms by which PD-1/PD-L1/PD-L2 signaling affects the pathophysiology of WM cells.

Disclosures

No relevant conflicts of interest to declare.
Enhancer-Promoter Looping Deciphers Dosage of the Haploinsufficient Transcription Factor, CUX1
Authors: Arthur Robert K , An Ningfei , Kahn Saira , McNerney Megan E.
Published: October 2019

One third of tumor suppressor genes encode haploinsufficient transcriptional regulators, including transcription factors and chromatin remodelers. This presents a major barrier in oncology, as tumor suppressor genes and transcription factors are inherently difficult to target therapeutically. It remains unknown how a 50% reduction of a transcriptional regulator translates at the cis-regulatory level into a malignant transcriptional program. It is imperative to address this question, in order to predict and target aberrant downstream pathways. CUX1 encodes a quintessential haploinsufficient transcription factor that is recurrently mutated or deleted, monoallelically, in high-risk myeloid neoplasms and across solid tumor types. We hypothesized that the transcriptional response to changes in CUX1 level is encoded within the cis-regulatory architecture of dosage-sensitive CUX1 target genes. In this study, we determined that CUX1 primarily binds distal enhancers, in a tissue-specific manner. CUX1 binding sites are significantly enriched for co-binding with transcriptional activators and cohesin components. Haploinsufficiency of CUX1 in K562 myeloid leukemia cells led to altered expression of mitotic and apoptotic genes with concomitant increased cellular proliferation. Surprisingly, ChIP-seq of CUX1 in the haploinsufficient state revealed a unimodal decrease in CUX1 occupancy genome-wide, with no relevance to differential gene expression. Thus we used a machine-learning algorithm to identify characteristics of CUX1 binding sites at dosage-sensitive target genes and revealed a relationship with distance to the transcription start site, chromatin accessibility, and enhancer activity. Finally, we demonstrate that CUX1 binding sites at dosage-sensitive genes loop to the promoter, and those genes with an intermediate number of Hi-C loops are most responsive to changes in CUX1 abundance. Overall, these data point to a novel mechanism of transcription factor dose-responsiveness mediated by enhancer-promoter looping.

Disclosures

No relevant conflicts of interest to declare.
Heterotrimeric G-Proteins Are Indispensable for FLT3-ITD autophosphorylation and Oncogenic Function
Authors: Rehage Maike , Wingert Susanne , Haetscher Nadine , Bothur Sabrina , Serve Hubert , Grez Manuel , Schwaeble Joachim , Rieger Michael A
Published: October 2019

Heterotrimeric G-proteins transmit signals of G-protein coupled receptors and regulate many basic cellular functions. However, their role in normal and malignant hematopoietic stem cells remains obscure. Activating mutations in the heterotrimeric G-protein Gaq were found in various cancers and its expression is enhanced in diffuse large B-cell lymphoma and T-ALL. Our previous data suggested the involvement of heterotrimeric G-proteins in Flt3-ITD-mediated leukemic transformation. FMS-like tyrosine kinase 3 with internal tandem duplication (FLT3-ITD) is a frequent oncoprotein in acute myeloid leukemia causing constitutive active STAT5 signaling. Here, we investigated a novel role of Gaq in Flt3-ITD-induced leukemic transformation.

We could show that Gaq is indispensable for aberrant FLT3-ITD activation and oncogenic function as Gaq activity is necessary to maintain the autophosphorylation of FLT3-ITD. Gaq abrogation resulted in diminished cell proliferation and colony formation as well as delayed leukemogenesis in vivo of Flt3-ITD leukemic cells. Importantly, the growth inhibition could be rescued by addition of IL3 and did not occur in the presence of FLT3 ligand-activated FLT3 wildtype receptor, demonstrating the specificity of Gaq requirement for FLT3-ITD oncogenic signaling. Interestingly, co-immunoprecipitations revealed a direct physical interaction between FLT3-ITD and Gaq which did not require phosphorylation of the receptor tyrosine kinase. Hence, FLT3-ITD hyperphosphorylation seems to be rather a consequence of the interaction than a prerequisite. Flt3-ITD-induced transformation of murine hematopoietic stem/progenitor cells (HSPCs) strictly depended on the presence of Gaq, and the ablation of Gaq/11 in transplanted Flt3-ITD-transduced HSPCs from conditional Gaq/11 double knock-out mice delayed leukemic burden. These findings of an unexpected, yet critical, role of Gaq place the molecule as an important target for antileukemic strategies.

Disclosures

No relevant conflicts of interest to declare.
Bacteremia, Not Coagulation Proteases Contribute to In Vivo Complement Activation in Sepsis
Authors: Keshari Ravi Shankar , Silasi-Mansat Robert , Lupu Cristina , Taylor Fletcher B. , Lupu Florea
Published: October 2019

Bacterial sepsis induces strong activation of coagulation, complement and fibrinolytic systems that contribute to disseminated intravascular coagulation, organ damage and death. While the contact of the blood with pathogens or pathogen-associated molecular patterns (PAMPs) can trigger the activation of both systems, a bidirectional complement-coagulation crosstalk is believed to occur. Although the role of complement activation products as positive regulators of coagulation is documented, direct activation of the complement proteins by thrombin or other hemostatic proteases was alluded but not demonstrated in vivo. Here we aimed to: (i) determine if in vivo generation of thrombin and other hemostatic proteases can activate the complement proteins and (ii) discriminate between the direct effect of the pathogen/PAMPs vs. hemostatic proteases on complement activation in a clinically relevant model of sepsis. We have compared the time-course of complement activation markers (C3b, C5a and C5b-9 terminal complex) in plasma of baboons exposed to 1010 cfu/kg (LD100) E. coli vs. intravenous infusion of factor Xa/PC:PS, a potent procoagulant stimulus. In baboons challenged with LD100 E. coli, complement activation markers C3b, C5a and C5b-9 reached maximum levels after 2 hrs (see figure). Complement activation coincided with the peak of bacteremia and LPS, but not with markers of thrombin generation (TAT and fibrinogen consumption; see figure) or fibrinolysis (FDP, D-dimers), which reached peak levels after 6 hours. Differently, infusion of FXa/PC:PS (36.6 pmol/L FXa and 56.3 nmol/L PC/PS per kg body weight) induced a rapid burst of thrombin and almost full consumption of fibrinogen during the first 10 min post-infusion, with no increase of complement activation markers. Based on these data we conclude that in vivo activation of the coagulation cascade does not support complement activation as was postulated by previous in vitro studies. Therefore, we conclude that pathogens and PAMPs are the main activators of the complement during sepsis while direct activation by hemostatic proteases is minor or absent.

Figure Figure.

Disclosures

No relevant conflicts of interest to declare.
Therapeutic Blockade of Macrophage Colony Stimulating Factor (CSF-1) Delays AML Progression in Mice In Vivo
Authors: Goh Sal Lee , Levesque Jean-Pierre , Petitt Allison R , Barbier Valarie , Winkler Ingrid G
Published: October 2019

Macrophage colony-stimulating factor (M-CSF or CSF-1) plays a role in regulating innate immune responses promoting macrophage growth and differentiation. We hypothesized CSF-1 may also play a role in growth and progression of Acute Myeloid Leukaemia (AML). The aim of this study is to investigate the role of CSF-1 in survival and chemo-resistance of leukaemia stem and progenitor cells (LSPC). We further hypothesized that blocking CSF-1R signalling in LSPC may dampen leukaemia survival in vitro and delay leukaemia progression in vivo.

AML was induced in mice by injecting murine Haematopoietic Stem and Progenitor Cells (HSPC) transduced with either MLL-AF9 or AML1- ETO fusion oncogenes for the development of either monomyelocytic or granulocytic leukaemia respectively. We found CSF-1R, the main receptor for CSF-1, was expressed on these acute myeloid leukaemia cells, thus it is possible that CSF-1 provide supportive microenvironment for leukemic growth. To identify whether CSF-1 in the bone marrow (BM) niche is essential for growth of malignant LSPC, we harvested normal or- leukaemic blasts from BM for in vitro studies using Long-Term Culture-Initiating-Cell (LT-CIC) assays. In these assays AML LSPC or normal HSPC cells were co-cultured with mesenchymal stromal cells (MSC) from either wildtype mice (MSC that produce CSF-1) or MSC from OP/OP mice (unable to produce functional CSF-1). We found normal (wild-type) HSPC were able to proliferate, survive and produce LT-CIC in the absence of niche-provided CSF-1, however AML blasts could not, unless rescued by addition of recombinant CSF-1 (100 ng/mL) in vitro. Together these data suggest CSF-1 signalling may be critical for AML LSPC but not normal HSPC.

Next we investigated in mice whether therapeutic CSF-1 blockade could similarly dampen AML survival or progression in vivo. Cohorts of mice were injected with luciferase-expressing monomyelocytic (MLL-AF9) BM leukaemic blasts, then 7 days later administered the small molecule CSF-1 antagonist (GW2580, 160mg/kg daily for 10 days) or vehicle control. Leukaemia progression was tracked by biweekly bioluminescence and testbleeds for appearance of GFP+ leukaemia blasts in blood. We found therapeutic blockade of CSF-1 significantly reduced tumour burden in these mice by both bioluminescence and testbleed analysis. Mice were also monitored for duration of survival. As anticipated by the observed reduction in leukaemia burden, therapeutic CSF-1 blockade also significantly extended the duration of overall mouse survival (P<0.005, n= 8 mice/ group).

Together these studies suggest therapeutic CSF-1 blockade may show promise as an adjunct therapy to help reduce tumour burden and improve success of AML leukaemia therapies.

Disclosures

Winkler: GlycoMimetics: Research Funding.
Improved Sensitivity in Detection of FMS-like Tyrosine Kinase Internal Tandem Duplication of a Method Using Next-Generation Sequencing Data
Authors: Shin Junghoon , Kim Daeyoon , Hong Yoojin , Koh Youngil , Yun Hongseok , Shin Dong-Yeop , Yoon Sung-Soo , Kim Inho , Lee Junglim , Kim Byung-Su
Published: October 2019

We developed new ITD detection algorithm (ITDetect) based on whole exome sequencing (WES) data for FMS-like tyrosine kinase internal tandem duplication (FLT3-ITD). ITDetect is based on BWA and is specified for ITD detection including FLT3-ITD. We validated and compared result of ITDetect with other ITD detecting algorithms using nested polymerase chain reaction (PCR) method. Nested PCR uses two types of primer specified for FLT3-ITD detection.

In 81 acute myeloid leukemia patients with WES data, FLT3-ITD was positive in 11 patients (13%) when called with ITDetect, all of whom were validated with nested PCR. Meanwhile FLT3-ITD was positive only in 7/81 patients by conventional PCR. The concordance rate of ITDetect and nested PCR was 95% (77/81). ITDetect showed better ITD detection performance when compared with previously reported ITD callers. In large AML cohort (n=213), patients who were positive for FLT3-ITD with nested-PCR but not with conventional PCR had shorter survival outcomes than patients who were negative for FLT3-ITD with nested PCR, suggesting clinical significance of sensitive FLT3-ITD detection.

In conclusion, we developed more sensitive detection methods for FLT3-ITD based on WES data that is clinically meaningful. Utilization of more sensitive detection method than conventional PCR in clinic should be considered.

Figure FLT3-ITD detection procedure. Figure. FLT3-ITD detection procedure. Figure Performance of various NGS ITD detectors. Figure. Performance of various NGS ITD detectors. Figure Survival comparison between patients positive for FLT3-ITD by nested PCR method but negative by conventional PCR method and those negative by both methods. Figure. Survival comparison between patients positive for FLT3-ITD by nested PCR method but negative by conventional PCR method and those negative by both methods.

Disclosures

No relevant conflicts of interest to declare.
Dual Inhibition of Histone Deacetylases and Phosphoinositide 3-Kinase Enhances Therapeutic Activity Against B Cell Lymphoma
Authors: Mondello Patrizia , Derenzini Enrico , Asgari Zahra , Philip John , Brea Elliot J , Seshan Venkatraman E , Hendrickson Ronald , de Stanchina Elisa , Scheinberg David A , Younes Anas
Published: October 2019

Oncogenic co-operation between c-Myc and activated phosphoinositide 3-kinase (PI3K) signaling pathways is crucial in lymphomagenesis, providing an opportunity for developing mechanism-based therapy to disrupt this co-operative survival mechanism. Combining constitutive c-Myc expression with constitutive PI3K activity in mouse germinal center B (GCB) cells resulted in Burkitt lymphoma-like tumors. Furthermore, analysis of primary human Burkitt lymphoma (BL) tissue sections revealed that two-thirds of the cases expressed high levels of phosphorylated AKT and S6 proteins, indicative of PI3K and mTORC1 activation. Prior attempts to develop small molecule inhibitors that specifically and directly target c-Myc protein have been unsuccessful. However, c-Myc cellular protein abundance can be decreased by using epigenetic modifying drugs (HDAC inhibitors or bromodomain/BET inhibitors) that are known to inhibit c-Myc transcription. Several investigators attempted disrupting c-Myc and PI3K cooperation by combining HDAC inhibitors and PI3K pathway inhibitors and synergic activity was demonstrated in DLBCL irrespective of subtype. In this study, we assessed the efficacy of CUDC-907, a new rationally designed dual inhibitor of PI3K and HDACs, in a panel of lymphoma cell lines. CUDC-907 treatment resulted in a dose- and time-dependent growth inhibition and cell death of DLBCL cell lines, irrespective of the cell of origin. CUDC-907 treatment down-regulated the phosphorylation of PI3K downstream targets, including AKT, PRAS40, S6, and 4EBP1, increased histone 3 acetylation, and decreased Myc protein levels. SILAC-based quantitative mass spectrometry demonstrated that CUDC-907 treatment decreased the protein levels of several components of the B cell receptor (BCR) and Toll like receptor (TLR) pathways, including BTK, SYK, and MyD88 proteins. These cellular changes were associated with an inhibition of NF-kB activation. CUDC-907 demonstrated in vivo efficacy with no significant toxicity in a human DLBCL xenograft mouse model. Collectively, these data provide a mechanistic rationale for evaluating CUDC-907 for the treatment of patients with c-Myc and PI3K-dependent lymphomas.

Disclosures

No relevant conflicts of interest to declare.
A Common Signaling Node Constitute Non-Oncogene Addiction in Kinase Driven Leukemia:Mechanism of Oncogne Addiction in CML
Authors: Kesarwani Meenu , Kincaid Zachary , Gomma Ahmed Ramadan , Huber Erika , Rohrabaugh Sara , Grimes H. Leighton , Azam Mohammad
Published: October 2019

Disclosures

No relevant conflicts of interest to declare.
Outcomes of Chronic Phase Chronic Myeloid Leukemia Patients Following Tyrosine Kinase Inhibitors Dose-Reductions
Authors: Kong Jee Hyun , Khoury Hanna Jean , Winton Elliott F. , Heffner Leonard T. , Gaddh Manila , Arellano Martha , El-Rassi Fuad , Kim Audrey S , Jillella Anand , Bodó Imre , Kota Vamsi
Published: October 2019

Introduction: Tyrosine kinase inhibitors (TKI) are overall well tolerated in chronic myeloid leukemia (CML) s, but more than 30% require dose reduction or change to another TKIs due to intolerance. Impact of TKI dose-reduction on outcomes in a "real world" setting is unknown, thus, we evaluated the characteristics and outcomes of chronic phase (CP)-CML patients who received doses of TKI lower than the label/FDA recommendation.

Method: CP-CML with at least 12 months of follow-up, with ISBCR/ABL1 available after dose reduction were selected. Last TKI was defined as TKI which were taken at the last follow up visit or before disease progression to accelerated (AP) or blast phase (BP). FDA approved doses of imatinib (IM), dasatinib (DAS), nilotinib (NIL), bosutinib (BOS), and ponatinib (PON) were 400mg, 100mg, 600mg (300mg BID), 500mg, and 45mg, respectively .

Results: Between January 2005 and April 2016, 173 CP-CML patients, started IM (75%), DAS (18%) NIL (5%) and PON, BOS on clinical trial in 2%. Overall Fifty-eight (33.5%) patients had TKI dose reduction. IM (n=15) dose was reduced to 75% (range, 25-75), DAS (n=15) to 50% (range, 20-80), NIL (n=15) to 50% (range, 13-67), BOS (n=15) to 80% (range, 40-80) and PON (n=15) to 33% (range, 33-67). Median age for patients that received dose-reduced TKI was 55 (range, 18-88), and 27% received > 3 prior TKIs. With a median follow up of 53.6 (range 13.4-183.7) months, only 1 progressed to AP, and none to BP. Overall 60% achieved MMR. Among 35 patients who achieved MMR before dose reduction, MMR was maintained in 25 (71.4%) for a median of 17.2 (2-97.9) months from dose-reduction. CMR was achieved in patients on a maintenance dose of IM, 100mg QD (n=8); DAS, 20mg QD (n=4); NIL 300mg QD (n=3) and BOS, 200mg QD (n=3).

Conclusion: Similar to data reported from clinical trials, TKI dose reduction appears to be safe and associated with high response rates. This data confirms that the minimal effective dose for each TKI remains to be defined.

Disclosures

Heffner: Pharmacyclics: Research Funding; AbbVie: Research Funding; Millennium: Research Funding; Celgene: Research Funding. Jillella:Leukemia Lymphoma Society: Research Funding. Kota:Ariad Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Leukemia Lymphoma Society: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees.
The Novel Missense Mutation of GATA1 Caused Red Cell Adenosine Deaminase Overproduction Associated with Congenital Hemolytic Anemia
Authors: Ogura Hiromi , Yamamoto Toshiyuki , Utsugisawa Taiju , Aoki Takako , Iwasaki Takuya , Ondo Yumiko , Kawakami Takahiro , Nakagawa Shinichiro , Ozono Shuichi , Inada Hiroko , Kanno Hitoshi
Published: October 2019

Red cell adenosine deaminase (ADA) overproduction (OMIM 102730) is a rare form of congenital hemolytic anemia. To date, only four independent families have been reported. Recently, we examined the red cell enzyme activities of an 18-year-old male Japanese patient with congenital hemolytic anemia, and diagnosed a new case of ADA overproduction. His ADA activity was measured as 39.7 IU/gHb, representing an over 30-fold elevation of the normal mean value. The patient's mother also showed a high red cell ADA, 7.40 IU/gHb, and the father had normal ADA activity. To elucidate the molecular basis of the elevated ADA activity, we performed a target-captured sequencing focusing on the 67 congenital-anemia related genes. The results showed that there was no structural mutation of ADA gene, and that the proband had a novel missense mutation of GATA1, c.920G>A, p.R307H. The proband was hemizygous, and the mother was heterozygous for the mutation. Subsequently, we examined a previously reported case of ADA overproduction, and identified the identical missense mutation of GATA1. These two cases had clinical similarities, such as low birth weight with hypospadias, splenomegaly, and slightly decreased platelet counts, suggesting that these cases could be categorized as X-linked anemia with or without neutropenia and/or platelet abnormality (XLANP, OMIM#300835). The previous case showed a rare blood type, Lu(a-b-) and a low beta/alpha globin synthetic ratio, whereas the present case depicted abnormal red cell morphology, such as stomatocytosis and target cells. Taken together, the missense mutation of GATA1 might cause the aberrant expression of erythroid-genes, inducing a short life-span of red cells.

Disclosures

No relevant conflicts of interest to declare.
Treatment Outcomes and Prognostic Factors of Patients with Relapsed Acute Myeloid Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation
Authors: Choi Yunsuk , Lee Jung-Hee , Lee Kyoo-Hyung , Park Han-Seung , Choi Eunji , Ko Sun-Hye , Seol Miee , Lee Young-Shin , Kang Young-Ah , Jeon Mijin , Lee Je-Hwan
Published: October 2019

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is the curative option for treatment of acute myeloid leukemia (AML). Even after HSCT, the relapse rate of AML ranged from 20% to 55%. The prognosis of relapsed AML after HSCT is very poor. But, treatment guideline for relapsed AML after HSCT has not been defined. Thus, we aimed to investigate treatment outcomes and prognostic factors of patients with relapsed AML after allogeneic HSCT.

Patient and Method: Among 624 patients with AML who received HSCT in Asan Medical Center, Korea between 1995 and 2014, 219 patients who had a relapse of AML after HSCT were included in this retrospective study.

Results: Seventy-two patients (32.9%) reattained complete remission (CR). Refractory AML at the time of HSCT (odds ratio [OR], 0.199, P=0.001), high BMI (> 28) (OR, 0.88, P=0.032), graft source from peripheral blood (OR, 0.299, P=0.001) and shorter relapse free interval (< 6 months) (OR, 0.199, P=0.001) were significant negative predictors for CR achievement (Table1). Of included patients, survival after relapse was median 5.2 months (95% CI, 3.96-6.44, months). Leukemia free survival of patients reattaining CR after relapse was median 10.6 months (95% CI, 8.1-13.2 months). Twenty-seven patients received second HSCT following salvage chemotherapy. Patients who had underwent upfront HSCT without chemotherapy for AML and relapse before 6months after HSCT were significantly associated with worse survival after relapse (Hazard ratio [HR], 3.106, P=0.006 and HR, 2.018, P=<0.001, respectively). Donor lymphocyte infusion following salvage chemotherapy and second HSCT had a significant impact on better survival (HR, 0.131, P=0.002 and HR, 0.423, P=0.003, respectively). Male gender (Hazard ratio [HR] 2.465, P=0.012) and extramedullary relapse (HR, 4.215, P=0.001) were negative factors affecting shorter leukemia free survival after relapse.

Conclusion: Donor lymphocyte infusion following salvage chemotherapy and second HSCT can be beneficial option for relapsed AML patients after HSCT. But, novel treatment modalities need to be investigated for improving survivals of relapsed AML patients after HSCT.

Disclosures

No relevant conflicts of interest to declare.
Mechanism of IL-10 Protective Effect in Development of Childhood B Cell Acute Lymphoblastic Leukemia
Authors: Fitch Briana , Hermiston Michelle L. , Wiemels Joseph L. , Kogan Scott C.
Published: October 2019

B-cell acute lymphoblastic leukemia (B-ALL) is the most common malignancy of childhood. While significant progress has been made in the treatment of B-ALL, the factors that influence the development of B-ALL remain poorly understood. Epidemiological studies have established a role of early childhood infections in altering leukemia risk. The focus of these studies has been on documenting the number and timing of infectious exposures; however, the role of host immune response to infections in B-ALL development is largely unknown. Low birth levels of the immunomodulatory cytokine interleukin 10 (IL-10) are associated with a 25 fold increased risk of developing childhood B-ALL. Mechanistically, IL-10 plays a critical role in controlling the neonatal immune response to infections. Together, these findings suggest that IL-10, an important regulator of host immune responsiveness, protects against childhood B-ALL.

To establish whether loss of IL-10 has an impact on leukemogenesis, we crossed Il10 knockout mice to the TEL-AML1 (ETVX6-RUNX1I) Ckdn2anull mouse model of childhood B-ALL. ETV6-RUNX1 t(12;21) is the most frequent chromosomal translocation in childhood B-ALLand one-fourth of these leukemias are observed in combination with loss of the Cdkn2a locus. The leukemia incidence in TEL-AML1 Ckdn2anull mice is 60%, therefore this is a robust and clinically relevant mouse model of childhood B-ALL. We used this model to assess the role of IL-10 in leukemogenesis by following Il10 knockout TEL-AML1 Ckdn2anull mice for the development of disease in comparison with control IL-10 expressing TEL-AML1 Ckdn2anull mice.

We found that Il10 knockout accelerated leukemogenesis in the presence of TEL-AML1. The cancer free survival of the IL-10 expressing TEL-AML1 Ckdn2anull mice (n=74) was 227 days, whereas the survival of IL-10 knockout mice (n=40) was reduced to 180 days (p<0.0005). These data support a causal role of low levels of IL-10 in the development of B-ALL and raise the possibility of using an IL-10 receptor agonist for leukemia prevention in children with high risk of B-ALL.

Thus, IL-10 loss is a defect in the host immune system that accelerates childhood B-ALL development, potentially through modifying immune responses to infections. Studies to understand the mechanism of how low IL-10 levels interact with infections to influence leukemogenesis are underway.

Disclosures

No relevant conflicts of interest to declare.
Efficacy of Pegaspargase, Etoposide, Methotrexate and Dexamethasone (PEMD) in Newly-Diagnosed Advanced-Stage Extra-Nodal Natural Killer (NK)/T-Cell Lymphoma
Authors: Xu Wei , Liang Jin-Hua , Wang Li , Fan Lei , Zhu Hua-Yuan , Li Jian-Yong
Published: October 2019

Objective: Determine efficacy and safety of PEMD (pegaspargase, etoposide, methotrexate, dexamethasone) in persons with newly-diagnosed advanced-stage extra-nodal NK/T-cell lymphoma.

Subjects and methods: Twenty-seven consecutive subjects with newly-diagnosed advanced-stage (stage III-IV) extra-nodal NK/T-cell lymphoma were prospectively studied from July, 2010 to August, 2015. All subjects received PEMD (methotrexate, 3.0 g/m2 IV over 6 h on day 1, etoposide, 100 mg/m2 IV on days 2-4, dexamethasone, 40 mg IV on days 1-4 and pegaspargase, 2500 U/m2 IM on day 2). Courses were given every 3 week. Primary co-endpoints were response and survival. Secondary endpoints were proportion of subjects completing planned therapy (4 to 6 cycles of PEMD regimen) and frequencies of adverse events.

Results: Median age was 46 y (range, 17-73 y). There were 21 males (78%). Nine subjects (33%) had non-nasal NK/T-cell lymphoma including 5 of the skin involvement, 1 of the testis involvement, 1 of the muscle involvement and 2 of the gastrointestinal tract involvement. Thirteen subjects (48%) had elevated serum LDH levels. Eleven subjects (41%) had higher level of EBV-DNA in blood (>5000 copies/mL). Twenty-one subjects (78%) had B-symptoms and 13 (48%) had an IPI score of 3-5. Subjects received a median of 4 courses of PEMD (range, 1-6). Median follow-up is 48 mo (range, 13-74 mo). Three patients had early death (within 3 mo after the diagnosis). Overall response rate (ORR) was 74% (95%CI 54%-89%) in the 27 subjects with advanced-stage disease including complete response (CR)/unconfirmed CR (CRu) in 12 (44% [95%CI 26%-65%]) and a partial response (PR) in 8 (30% [95%CI 14%-50%]). Four-year progression-free survival (PFS) was 44% (95%CI 25%-63%) and overall survival (OS) 51% (95%CI 32%-70%) (Figure 1). PFS and OS were not correlated between nasal and non-nasal types of ENKTL. There was no treatment-related death or serious allergic reactions. The most common grade-3/-4 hematologic complication was neutropenia (37% [95%CI 19%-58%]). The most common non-hematologic complications were infection (16% [95%CI 4%-34%]) and hypo-fibrinogenemia (12% [95%CI 2%-29%]).

Conclusion: PEMD is effective and safe in persons with newly-diagnosed advanced-stage extra-nodal NK/T-cell lymphoma.

Figure 1. PFS and OS for all the patients (N=27). Figure 1. PFS and OS for all the patients (N=27).

Disclosures

No relevant conflicts of interest to declare.
Decitabine Priming Enhances Mucin 1 Inhibition Mediated Disruption of Redox Homeostasis in Cutaneous T-Cell Lymphoma
Authors: Jain Salvia , Washington Abigail J. , Leaf Rebecca Karp , Bhargava Parul , Clark Rachael , Kupper Thomas S. , Stroopinsky Dina , Pyzer Athalia Rachel , Cole Leandra , Nahas Myrna R. , Apel Arie , Rosenblatt Jacalyn , Arnason Jon , Kufe Donald , Avigan David E.
Published: October 2019

Background: Cutaneous T-cell lymphoma (CTCL) is a heterogeneous neoplasm and patients with relapsed/refractory disease exhibit resistance to standard cytotoxic therapies. We have previously demonstrated that the MUC1-C oncoprotein plays a critical role in regulating apoptosis and protection from oxidative stress in CTCL. Targeting of MUC1-C with a pharmacologic inhibitor, GO-203, was associated with late apoptosis and early necrosis and slowing of tumor growth in in vitro and in vivo models of CTCL, respectively. However, disease responses following MUC1-C inhibition were incomplete underscoring the need for combinatorial strategies that could exploit the vulnerability of CTCL cells to oxidative signals. Decitabine is a DNA methyltransferase inhibitor, previously shown to modulate oxidative stress in acute myeloid leukemia models. We hypothesized that treatment with decitabine and GO-203 would present a potent novel therapeutic combination for patients with CTCL.

Method/Results: Our studies demonstrate that exposure of CTCL cells to decitabine in combination with GO-203, increased the generation of reactive oxygen species (ROS) and decreased levels of scavenger molecules, NADPH, glutathione (GSH), and TIGAR, a p53-inducible regulator of glycolysis and apoptosis, critical to intracellular redox homeostasis. This in turn led to marked increase in the ratio of stress activated proteins; phospho-p38 and phospho-JNK to Total-p38 and Total-JNK repectively. Further dual exposure to GO-203 and decitabine resulted in near abrogation of DNA methyl transferase 1 and 3b crucial for maintaining DNA methylation, demonstrating significant synergy of these agents for inducing hypomethylation. In concert with these findings, treatment with decitabine and GO-203 upregulated the ROS generating enzyme, NADPH oxidase 4 (Nox4) potentially due to their effect on epigenomic regulation of this protein. In concert with these findings, exposure to decitabine and GO-203 resulted in heightened apoptotic death of CTCL cell lines, primary patient derived samples and in a aggressive murine xenograft model.

Conclusion: These findings indicate that decitabine augments MUC1-C inhibition induced redox imbalance and provides a novel combination of targeted and epigenetic agents for treatment of patients with CTCL. Accordingly an early phase multi-institution clinical trial to to investigate this combinatorial strategy based on epigenetic modulation of redox homeostasis in patients with relapsed/refractory T cell lymphomas is being planned.

Disclosures

Rosenblatt: Astex: Research Funding; BMS: Research Funding; DCPrime: Research Funding. Arnason:Gilead: Consultancy. Kufe:Genus Oncology LLC: Consultancy, Equity Ownership.
Benefit of Consolidative Radiotherapy in Patients with Limited Stage Diffuse Large B-Cell Lymphoma in the Rituximab Era
Authors: Nakamura Nobuhiko , Ikoma Yoshikazu , Shibata Yuhei , Matsumoto Takuro , Ninomiya Soranobu , Kitagawa Junichi , Shimizu Masahito , Hara Takeshi , Tsurumi Hisashi
Published: October 2019

Background: Diffuse large B-cell lymphoma (DLBCL) is an aggressive type of non-Hodgkin lymphoma and the most common lymphoid neoplasm in adults. In the pre rituximab era, the standard therapy for patients with limited stage DLBCL had been three cycles of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) followed by involved-field radiotherapy (IFRT). The addition of rituximab has revolutionized the treatment of DLBCL. Rituximab combined with CHOP (R-CHOP) has been established as the standard treatment for patients with DLBCL. However, the role of consolidative radiotherapy (RT) in the treatment of limited stage DLBCL in the rituximab era is controversial.

Patients and Methods: We retrospectively analyzed 108 patients with limited stage DLBCL who received R-CHOP or R-THP-COP (rituximab plus, cyclophosphamide, pirarubicin, vincristine and prednisone) regimen between June 2004 and August 2015. We compared overall survival (OS) and progression-free survival (PFS) according to the treatment. OS was calculated from the date of initiation of chemotherapy to the date of the last follow-up or death. PFS was calculated from the date of initiation of chemotherapy to the date of progression disease, death, or last contact, whichever occurred first. Survival was estimated from Kaplan-Meier curves and compared using the log-rank test. P < 0.05 was considered statistically significant. Weighted Cox proportional hazards regression modeling with the inverse probability weighted (IPW) estimators method adjusting to propensity for RT was used to account for differences in baseline characteristics.

Results: Median age at diagnosis was 66 years (19-88 years), with 61 males and 47 females. Forty-three patients (40%) had stage I, and 65 patients (60%) received consolidative RT after chemotherapy. Patients who received consolidative RT were significantly younger (65 vs 72, P < 0.01) and were more likely to have stage I disease (51% vs 23%, P < 0.01). The median number of chemotherapy cycles was 4 (range 3-8) in patients who received RT, and 6 (range 3-8) in patients who did not. Median follow-up was 4.3 years (0.3-10.9 years), and the 5-year OS (92% vs 63%, P < 0.01) and PFS (87% vs 65%, P < 0.01) were significantly higher for patients who received RT than those who did not. Using IPW adjustment, RT remained predictive of OS (HR 0.30, CI 0.13-0.72, P < 0.01) and PFS (HR 0.47, CI 0.22-0.99, P < 0.05).

Conclusion: Our results suggest that consolidative RT improves OS and PFS in patients with limited stage DLBCL in the rituximab era. Although consolidative RT seems to be gradually phased out by chemotherapy alone, it is still an important treatment strategy.

Disclosures

No relevant conflicts of interest to declare.
The Effect of Therapy on High Grade B Cell Lymphoma, Not Otherwise Specified and Outcomes in Comparison with Double Hit Lymphoma
Authors: Rush Jonathan , Sehgal Alison R. , Roth Christine G. , Boyiadzis Michael
Published: October 2019

Background: High grade B cell lymphoma (HGBL) is a heterogeneous entity with morphologic and genetic features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (BL). Many patients with HGBL also have concurrent MYC, BCL2 and/or BCL6 rearrangements documented by FISH, the so-called double-hit lymphoma (DHL), which has now been defined as a separate entity in the updated WHO classification in 2016 as HGBL with rearrangements of MYC and BCL2 and/or BCL6. Other HGBL without MYC and BCL2 or BCL6 have been termed HGBL, NOS. HGBL, NOS and DHL are considered clinically aggressive. The best therapeutic approach for HGBL, NOS is unclear, and outcomes of patients with DHL in comparison to HGBL, NOS are not well established.

Objective: The aim of this study was to evaluate and describe the outcomes and practice patterns for patients with HGBL, NOS. Additionally, we compared the survival of patients with HGBL, NOS to those with DHL.

Materials and Methods: This retrospective cohort study was conducted at the University of Pittsburgh Medical Center. All patients identified as HGBL by pathology review at the University of Pittsburgh Hematopathology Department from 2010-2014 were included. Outcomes between standard therapy with R-CHOP and high intensity therapies with either R-EPOCH or R-HyperCVAD were compared for those patients with HGBL. Survival curves were generated with the Kaplan-Meier method, and overall survival was compared using the log-rank test. Cox-regression analysis was used to adjust for covariates.

Results: 50 patients with newly diagnosed HGBL without a double-hit genotype were identified. Of these patients, 38 received R-CHOP (63%), R-EPOCH (21%) or R-HyperCVAD (16%). Baseline characteristics between treatment groups (Table 1) revealed an older age (p=0.033) and more frequent germinal center genotype (p=0.023) in those treated with R-CHOP. Median follow-up for this group was 18 months. There was no difference in the overall survival (OS) between R-CHOP and higher intensity regimens (p=0.540) (Figure 1). Median survival was not reached in either group. 2-year survival was 76%. Only a high-risk IPI score retained prognostic significance with OS in multivariate analysis (p=0.022). This compares favorable to 13 cases of DHL treated with R-CHOP, R-EPOCH, or R-HyperCVAD during a similar time period for whom the median overall survival was 8.9 months (p=0.016)

Conclusion: Both standard therapy with R-CHOP and higher intensity therapies appear to be effective in the treatment of HGBL without double-hit genotype. IPI score remains prognostically significant. Outcomes in patients with HGBL, NOS appear favorable in comparison with patients with DHL.

Figure Figure.

Disclosures

No relevant conflicts of interest to declare.