scholarly journals Epigenetic Drug Combination Chemo-Sensitizes Pediatric AML By Reducing Cell Adhesion and Dislodging AML Cells from the Bone Marrow

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2637-2637
Author(s):  
Samantha Weber ◽  
Anilkumar Gopalakrisnapillai ◽  
E. Anders Kolb ◽  
Sonali Barwe
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Drug Combination ◽  
Epigenetic Therapy ◽  
Cell Contact ◽  
Advisory Committees ◽  
Epigenetic Drugs ◽  
Epigenetic Drug ◽  
Direct Cell ◽  
Pediatric Aml

Abstract Background We showed earlier that prolonged treatment with a combination of azacitidine (DNMT1 inhibitor) and panobinostat (HDAC inhibitor) induced complete remission in a disseminated xenograft model of KMT2A rearranged AML (Gopalakrishnapillai et al., 2017, Leuk Res). Pretreatment with epigenetic drugs has been shown to induce chemo-sensitivity in some malignancies. However, studies on the use of epigenetic drugs in overcoming chemoresistance mediated by the bone marrow microenvironment are limited. The aim of this study was to determine the merit of incorporating epigenetic therapy with chemotherapy in AML treatment regimen and to identify the mechanism by which epigenetic drugs can chemosensitize AML. Methods AML cell lines and PDX lines were co-cultured with HS5 bone marrow stromal cells. Cell viability following drug treatment was assessed by flow cytometry. For determination of cell adhesion, violet proliferation dye stained AML cells were co-cultured with HS5 cells. Following treatment, non-adherent cells were removed by washes with phosphate buffered saline. The number of adherent AML cells was determined by flow cytometry. NSG-B2m mice were engrafted with MV4;11 cells and bled regularly to evaluate disease progression. Once engraftment was confirmed mice were assigned to treatment groups. Epigenetic therapy constituted azacitidine and panobinostat (2.5 mg/Kg each; Qd5). Chemotherapy constituted cytarabine (50 mg/Kg; Qd5) and daunorubicin (1.5 mg/Kg; Qd3). Mice were euthanized when they reached predetermined experimental endpoints. All animal studies were approved by the Institutional Animal Care and Use Committee. Results AML cells in co-culture with HS5 bone marrow stromal cells were less sensitive to chemotherapeutics cytarabine and daunorubicin compared to AML cells in monoculture. This chemoprotection was not achieved when AML cells were cultured in HS5 conditioned media or in Transwell inserts suspended over HS5 monolayers, suggesting that direct cell-to-cell contact was required. MV4;11 cells exposed to epigenetic drugs or cytarabine alone retained 70% viability. Pre-treatment with the epigenetic drug combination of azacitidine and panobinostat prior to cytarabine exposure greatly reduced cell viability in MV4;11 cells harboring KMT2A fusion (Fig. 1A). Similar chemo-sensitization was observed when four distinct KMT2A rearranged PDX lines were used ex vivo. This sensitization was accompanied by reduced binding of AML cells to HS5 cells following treatment with epigenetic drugs (Fig. 1B). We evaluated the efficacy of the epigenetic therapy and chemotherapy combination in disseminated xenograft models of pediatric AML. NSG-B2m mice transplanted with MV4;11 cells via the tail vein were randomly assigned to four groups - 1) vehicle, 2) epigenetic therapy 3) chemotherapy (cytarabine + daunorubicin), and 4) epigenetic therapy followed by chemotherapy. The mice receiving the epigenetic therapy and chemotherapy combination survived significantly longer than mice treated with any other condition (Fig. 1C). To assess the leukemic cell distribution in peripheral blood, bone marrow and spleen following treatment, a cohort of mice receiving epigenetic therapy alone or chemotherapy alone were euthanized a day after treatment concluded. The percentage of leukemic cells in bone marrow and spleen was lower in mice treated with epigenetic therapy than those treated with chemotherapy, consistent with the survival data. Surprisingly, the peripheral blood counts were significantly higher in mice receiving epigenetic drug combination. These results together with our in vitro data indicate that epigenetic therapy induces mobilization of AML cells to the blood stream. This increased availability of AML cells may promote enhanced sensitivity to chemotherapy. Conclusion Our data suggest that direct cell-to-cell contact plays a major role in mediating chemoprotective effects of the bone marrow microenvironment. These chemoprotective effects can be overcome by pretreatment with epigenetic drug combination azacitidine and panobinostat. Epigenetic drugs interfere with AML cell interactions with the microenvironment and dislodge AML cells from their protective niche. Thus, mobilization of AML cells to peripheral blood is a potential mechanism of chemo-sensitization mediated by epigenetic drugs. Disclosures Kolb: Servier: Membership on an entity's Board of Directors or advisory committees; Roche- Genentech: Membership on an entity's Board of Directors or advisory committees.

Abstract 15392: Inflammation and Ischemic Heart Failure: Monocyte-Mediated Cardiac Fibroblast Activation and Matrix Remodeling Through a Direct Cell-Cell Contact Mechanism

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Holly E Mewhort ◽  
Brodie D Lipon ◽  
Daniyil A Svystonyuk ◽  
David G Guzzardi ◽  
Paul W Fedak
Keyword(s):  
Peripheral Blood ◽  
Cardiac Fibroblast ◽  
Cell Contact ◽  
Β1 Integrin ◽  
Blood Monocytes ◽  
Peripheral Blood Monocytes ◽  
Fibroblast Activation ◽  
Direct Cell ◽  
Tgf Β1 ◽  
Cell Cell

BACKGROUND: Following myocardial infarction (MI), activated cardiac myofibroblasts facilitate extracellular matrix (ECM) remodeling to prevent mechanical complications. However, prolonged myofibroblast activity leads to dysregulation of the ECM, maladaptive remodeling, fibrosis and heart failure (HF). Chronic inflammation is believed to drive persistent myofibroblast activity, however, the mechanisms are unclear. In this study, we explored the effects of peripheral blood monocytes on human cardiac fibroblast activation in a 3D ECM microenvironment. METHODS/RESULTS: Human cardiac fibroblasts isolated from surgical human heart biopsies were seeded into 3D collagen matrices. Peripheral blood monocytes isolated from healthy human donors were co-cultured with fibroblasts. Monocytes increased fibroblast activation measured by collagen ECM contraction (17.9±11.1% increase; p<0.01) and resulted in local ECM remodeling observed by confocal microscopy. Under co-culture conditions that prevent cell-cell contact but allow interaction via paracrine factors, monocytes had minimal effects on fibroblast activation (6.4±7.0 vs.17.9±11.1% increase, respectively; p<0.01). Multiplex analysis of the co-culture media revealed an increase in the paracrine factors Transforming Growth Factor-beta 1 (TGF-β1) and Matrix Metalloproteinase 9 when monocytes and fibroblasts were cultured under cell-cell contact conditions (162.2±11.7pg/mL and 17.5±0.5ng/mL, respectively, vs. 21.8±5.7pg/mL and 4.9 ±0.4ng/mL; p<0.001). TGF-β1 blockade abolished monocyte induced cardiac fibroblast activation, as did β1-integrin. These data suggest direct cell-cell interaction between monocytes and cardiac fibroblasts through β1-integrin results in TGF-β1 release facilitating fibroblast activation and matrix remodeling. CONCLUSION: For the first time, we demonstrate that peripheral blood monocytes stimulate human cardiac fibroblast activation through a mechanism involving TGF-β1 release as a consequence of direct cell-cell interaction through β1-integrin. These data implicate inflammation as a driver of cardiac fibrosis post-MI, highlighting potential novel therapeutic targets for the treatment of ischemic HF.

scholarly journals Architecture of Sample Preparation and Data Governance of Immuno-Genomic Data Collected from Bone Marrow and Peripheral Blood Samples Obtained from Multiple Myeloma Patients

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 17-18
Author(s):  
Shaadi Mehr ◽  
Daniel Auclair ◽  
Mark Hamilton ◽  
Leon Rozenblit ◽  
Hearn Jay Cho ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Board Of Directors ◽  
Peripheral Blood ◽  
Large Scale ◽  
Mass Cytometry ◽  
Data Governance ◽  
Advisory Committees ◽  
Blood Samples ◽  
Data Files

Abstract: Title: Architecture of sample preparation and data governance of Immuno-genomic data collected from bone marrow and peripheral blood samples obtained from multiple myeloma patients In multiple myeloma (MM), the interactions between malignant plasma cells and the bone marrow microenvironment is crucial to fully understand tumor development, disease progression, and response to therapy. The core challenge in understanding those interactions has been the establishment of a standard process and a standard model for handling the data quality workflow and the underlying data models. Here we present the Platform (Figure 1), an integrated data flow architecture designed to create data inventory and process tracking protocols for multi-dimensional and multi-technology immune data files. This system has been designed to inventory and track peripheral blood and bone marrow samples from multiple myeloma subjects submitted for immune analysis under the MMRF Immune Atlas initiative (figure 2), and the processing and storage of Single Cell RNA-seq (scRNA-seq) and Mass Cytometry time-of-flight (CyTOF) data files derived from these immune analyses. While these methods have been previously applied on both tumor and immune populations in MM [2,3], this level of multi-institutional and multi-technology is unique. The Cloud Immune-Precision platform contains standardized protocols and bioinformatics workflows for the identification and categorization of immune cell populations and functional states based upon scRNA-seq gene signatures (ref: Bioinformatics manuscript in submission) and CyTOF protein signatures. Upon further expansion, it will contain high dimensional scRNAseq and CyTOF immune data from both bone marrow and peripheral blood samples from myeloma patients enrolled in the Multiple Myeloma Research Foundation (MMRF) CoMMpass study (NCT01454297) [1] (Figure 3). The architecture covers the automation of data governance protocols, data transformation and ETL model developments that will create an immune proteomic and profiling database and its integration into clinical and genomics databases: e.g. the MMRF CoMMpass clinical trial. This large-scale data integration will establish a cutting-edge Immune-Precision central platform supporting large scale, immune-focused advanced analytics in multiple myeloma patients. This platform will allow researchers to interrogate the relationships between immune transcriptomic and proteomic signatures and tumor genomic features, and their impact on clinical outcomes, to aid in the optimization of therapy and therapeutic sequencing. Furthermore, this platform also promotes the potential to (further) elucidate the mechanisms-of-action of approved and experimental myeloma therapies, drive biomarker discovery, and identify new targets for drug discovery. Figure 1: Cloud Immune-Precision Platform (Integrated data flow architecture designed to create data inventory and process tracking protocols for multi-dimensional and multi-technology immune data files) Figure 2: Sample tracking process architecture Figure 3: Data file creation and repository process tracking References: 1- Settino, Marzia et al. "MMRF-CoMMpass Data Integration and Analysis for Identifying Prognostic Markers." Computational Science - ICCS 2020: 20th International Conference, Amsterdam, The Netherlands, June 3-5, 2020, Proceedings, Part III vol. 12139 564-571. 22 May. 2020, doi:10.1007/978-3-030-50420-5_42 2- Ledergor, Guy et al. "Single cell dissection of plasma cell heterogeneity in symptomatic and asymptomatic myeloma." Nature medicine vol. 24,12 (2018): 1867-1876. doi:10.1038/s41591-018-0269-2 3- Hansmann, Leo et al. "Mass cytometry analysis shows that a novel memory phenotype B cell is expanded in multiple myeloma." Cancer immunology research vol. 3,6 (2015): 650-60. doi:10.1158/2326-6066.CIR-14-0236-T Figure 1 Disclosures Bhasin: Canomiiks Inc: Current equity holder in private company, Other: Co-Founder. Dhodapkar:Amgen: Membership on an entity's Board of Directors or advisory committees, Other; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Other; Janssen: Membership on an entity's Board of Directors or advisory committees, Other; Roche/Genentech: Membership on an entity's Board of Directors or advisory committees, Other; Lava Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other; Kite: Membership on an entity's Board of Directors or advisory committees, Other.

scholarly journals A Prognostic Human Splicing Signature That Precurses Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 877-877 ◽  
Author(s):  
Meenakshi Venkatasubramanian ◽  
Xiaoting Chen ◽  
Kashish Chetal ◽  
Aishwarya Kulkarni ◽  
Kasiani C. Myers ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Alternative Splicing ◽  
Board Of Directors ◽  
Protein Isoforms ◽  
Splicing Factor ◽  
Healthy Population ◽  
Rna Seq ◽  
Advisory Committees ◽  
Factor Expression ◽  
Pediatric Aml

Abstract Alternative splicing is a primary mechanism used to achieve mRNA transcript and proteomic diversity in higher-order eukaryotes. While alternative splicing is a recognized oncogenic driver in a small percentage of adult acute myeloid leukemia (AML) cases (~10-15%), splicing factor mutations are rarely found in pediatric AML. To discover splicing heterogeneity within diverse cancers in the absence of known causal mutations we developed a new computational workflow called OncoSplice. This workflow incorporates unsupervised splicing pattern analysis to iteratively identify novel patient splicing-defined subtypes (splice-ICGS algorithm), in conjunction with new integrative methods for cis-regulatory motif, CLIP-Seq binding and splicing factor expression data analysis (Fig. 1a). Analysis of RNA-Seq data from over 800 AML diagnosis samples identified subtypes associated with nearly all known splicing factor mutations in addition to over a dozen novel splicing-defined subtypes. Novel splicing subtypes were confirmed in independent patient cohorts and were associated with the expression or mutation of oncogenes (MYC, TP53, NPM1), oncofusions (CBFB-MYH11, MLL, PML-RAR, RUNX1), or the regulation of diverse splicing factors (U2AF1, SRSF2, HNRNPK). Both adult and pediatric AML are most frequently characterized by a single predominant splicing signature which divides the majority of AML patients into subtypes with splicing events overlapping those found in patients with mutations in U2AF1 or SRSF2 (Figure 1b). These "U2AF1-covarying" or "SRSF2-covarying" (CV) occur independently of splicing-factor mutations and were principally linked to mis-splicing rather than differential gene expression. Unlike patients with U2AF1-S3F mutations, U2AF1-CV splicing events are associated with canonical rather than altered U2AF1 binding specificity (Fig. 1c). In both adult and pediatric AML, U2AF1-CV splice events result in a shift towards longer protein isoforms associated with stem and progenitor programs, have significantly worse outcomes (poor survival and increased relapse) and are persistent during relapse in adults (Fig. 1d). Survival correlated U2AF1-CV splicing events were statistically enriched in genes required for leukemic growth based on a published CRISPR dropout screen. U2AF1-CV splicing was not associated with prior described epigenetic AML subtypes, but appears to be dependent on the expression of MYC and downstream splicing regulators (WDR77 and PRMT5). Surprisingly, RNA-Seq analysis of CD34+ bone marrow progenitors in healthy donors finds the same overall skewing in a subset of U2AF1-CV or SRSF2-CV splicing events as those found in AML. Distinct sorted progenitor populations (HSC, Multi-Lin, CMP, GMP, MEP) further show consistent U2AF1-CV or SRSF2-CV skewing within progenitors from the same donors, indicating that this is not a cell-type associated splicing difference. Hence, our data suggest that healthy bone marrow is skewed in the healthy population towards either U2AF1 or SRSF2 splicing pathways and that these splicing profiles impact future oncogenic transformation and patient survival in AML. These data further suggest a paradigm shifting model, in which widespread coordinated pathogenic splicing occurs across cancers, likely via imbalances in splicing factor expression, regulation or mutation. Figure 1. a) Steps implemented in the OncoSplice splicing subtype discovery workflow for splicing event quantification (MultiPath-PSI), iterative unsupervised splicing subtype discovery (splice-ICGS), supervised splicing subtype discovery (Bridger) and RNA-regulatory splicing subtype prediction (RBP-Finder). b) Comparison of splicing events enriched in adult AML with splicing factor mutations identifies their coincidence with U2AF1-CV and SRSF2-CV splicing events. c) Analysis of U2AF1 binding-site preferences at the e-3 splice-site position for cassette-exon splicing events (U2AF1-S34-specific but not U2AF1-CV; occurring in U2AF1-S34; occurring in U2AF1-CV; U2AF1-CV-specific but not U2AF1-S34). d) Kaplan-Meier curves for overall survival in patients from TCGA (top) and TARGET (bottom) with associated coxph p-values (all splice-ICGS stringently classified U2AF1-CV versus all other considered AMLs). Analysis of TCGA was restricted to cytogenetically normal AMLs with no splicing factor mutations and under 60 years of age. Figure 1. Figure 1. Disclosures Myers: Bellicum Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Sequencing of Circulating Cell-Free DNA in Patients with AML Detects Clinically Significant Mutations Not Detected in Bone Marrow: The Role for Complementary Peripheral Blood and Bone Marrow Genomic Analysis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2592-2592
Author(s):  
Nicholas J. Short ◽  
Keyur Patel ◽  
Maher Albitar ◽  
Miguel Franquiz ◽  
Rashmi Kanagal-Shamanna ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Board Of Directors ◽  
Peripheral Blood ◽  
Research Funding ◽  
Cell Transplant ◽  
Advisory Committees ◽  
Cell Free Dna ◽  
Non Invasive ◽  
Free Dna ◽  
Circulating Cell Free Dna

Background: Circulating cell-free DNA (ccfDNA) is highly fragmented DNA in plasma that is released by normal or tumor cells when they undergo apoptosis or necrosis. ccfDNA allows for non-invasive sampling of somatic genomic alterations and is informative in various solid tumors, including as a marker of measurable residual disease (MRD). We sought to assess the utility of baseline assessment and tracking of leukemia-associated mutations through peripheral blood sampling of ccfDNA in patients (pts) with acute leukemias. Methods: Plasma ccfDNA was isolated and analyzed using a next-generation sequencing (NGS) assay of 275 genes. This NGS analysis is based on Single Primer Extension library preparation with unique molecular identifier (Qiagen, Germantown, MD); a sequence coverage ≥ 100X (after removing duplicates) was required. Amplicon-based NGS was also performed on DNA extracted from the bone marrow (BM) in a CLIA-certified molecular diagnostics laboratory. This BM panel detects mutations in the coding sequence of 28 leukemia-associated genes, with an analytic sensitivity of 5-10%. The ccfDNA panel included all 28 genes evaluated on the BM NGS panel (ABL1, ASXL1, BRAF, DNMT3A, EGFR, EZH2, FLT3, GATA1, GATA2, HRAS, IDH1, IDH2, IKZF1, JAK2, KIT, KRAS, MDM2, MLL, MPL, MYD88, NOTCH1, NPM1, NRAS, PTPN11, RUNX1, TET2, TP53, WT1). Established bioinformatics pipelines were used to identify somatic variants. Results: Twenty-four pts (AML, n=22; ALL, n=2) underwent paired ccfDNA and BM sequencing at diagnosis prior to receiving frontline intensive chemotherapy. For baseline samples, ccfDNA was collected a median of 6 days after BM collection (range, 0-27 days) and a median of 0.5 days after start of induction chemotherapy (range, -7 to 7 days). Eleven pts (46%) also had ccfDNA collected at ≥1 time point during remission. Among the 28 genes of interest, the median number of mutations per pt detected in BM and in ccfDNA was 1 (range, 0-4) for both assays (P=0.39). A total of 40 mutations were detected: 18 mutations (45%) were detected by both methods, 7 (18%) were detected only in ccfDNA, and 15 (38%) were detected only in BM. Time from start of chemotherapy until ccfDNA collection did not appear to impact the concordance of ccfDNA and BM mutation analysis (P=0.87). Among mutations detected by ccfDNA in baseline samples, the median variant allelic frequency (VAF) was 33.7% (range, 2.7-90.8%). Among the 18 overlapping mutations, the concordance of VAF assessment by both methods was high (R2 = 0.849). Mutations detected by only one of the two methods were generally of lower VAF than those detected by both methods, suggesting that either method may miss small subclonal populations. The median VAF of mutations (as measured in ccfDNA) that were detected by both methods was higher than those detected only in ccfDNA (39.8% vs 25.2%, respectively; P=0.04); similarly, the median VAF of mutations (as measured in BM) that were detected by both methods was higher than those detected only in BM (40.2% vs 6.6%; P=0.001). Among the 7 mutations detected only by ccfDNA, ASXL1 was detected in 2 pts, WT1 in 1 pt, IDH1 in 1 pt, and BRAF and two EGFR mutations in 1 pt. Among the 5 pts in whom mutations were detected in ccfDNA but not BM, 2 eventually relapsed. In both pts, the discordant mutation (IDH1 and ASXL1) was detected in the relapse BM, suggesting that these were true mutations that were missed by NGS of the baseline BM. ccfDNA detected leukemia-associated mutations during remission that appeared to herald overt relapse (Figure 1). Two pts with t(8;21) AML developed new RUNX1 mutations detected by ccfDNA while in remission and subsequently relapsed 3 months and 14 months later. In both of these pts, the new RUNX1 mutation was confirmed in the BM at the time of morphological relapse. Another pt with AML had persistent TP53 and TET2 mutations detected by ccfDNA 1 month after allogeneic stem cell transplant and subsequently relapsed 1 month later. Conclusions: This study demonstrates that sequencing of ccfDNA can identify prognostic or targetable mutations not detected by BM NGS. However, true mutations were missed by both ccfDNA and BM analysis, suggesting that these methodologies may be complementary in the assessment and monitoring of pts with leukemia. The use of ccfDNA as a non-invasive method to detect mutations and track MRD in AML and other leukemias should be evaluated in larger, prospective cohorts. Disclosures Short: Takeda Oncology: Consultancy, Research Funding; AstraZeneca: Consultancy; Amgen: Honoraria. Jabbour:Amgen: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Cyclacel LTD: Research Funding; AbbVie: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Garcia-Manero:Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Kantarjian:BMS: Research Funding; Amgen: Honoraria, Research Funding; Agios: Honoraria, Research Funding; Immunogen: Research Funding; Takeda: Honoraria; Novartis: Research Funding; Ariad: Research Funding; Astex: Research Funding; Pfizer: Honoraria, Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Research Funding; Jazz Pharma: Research Funding; Cyclacel: Research Funding; AbbVie: Honoraria, Research Funding. Ravandi:Macrogenix: Consultancy, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Consultancy, Research Funding; Menarini Ricerche: Research Funding; Cyclacel LTD: Research Funding; Selvita: Research Funding.

Mesenchymal Stem Cells Promote Survival of Leukemic Cells Via Integrin-Linked Kinase (ILK)-Dependent Akt and STAT3 Activation: Implications for Leukemia Therapy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3377-3377
Author(s):  
Yoko Tabe ◽  
Linhua Jin ◽  
Gordon B. Mills ◽  
Yuko Tsutsumi-Ishii ◽  
Michael Andreeff ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Annexin V ◽  
Suspension Cultures ◽  
Leukemic Cells ◽  
Cell Contact ◽  
Nb4 Cells ◽  
Stat3 Signaling ◽  
Direct Cell ◽  
Integrin Linked Kinase ◽  
Marrow Stroma

Abstract The β integrins play an important role in the cell-to-cell interactions, which trigger intracellular signal transduction pathways. Integrin-linked kinase (ILK) has been shown to directly interact with β integrins and phosphorylate Akt, which promotes cell survival. On the other hand, PI3K/Akt and JAK/STAT signaling pathways are also recognized as potent anti-apoptotic mediators activated by ligation of growth factor receptors. We have previously demonstrated that stroma cells protect acute promyelocytic leukemic (APL) cells from apoptosis (Tabe, Blood103:1815–1822, 2004). Here, we investigate the ability of bone marrow stroma cells to activate Akt, STAT3, and ILK signaling in leukemic cells co-cultured with stroma in low-serum conditions (0.5% FCS). Human mesenchymal stem cells (MSC), co-cultivated with APL-derived NB4 cells in direct cell-to-cell contact, partially inhibited spontaneous apoptosis and enhanced viability of NB4, while separation from stromal cells by transwell insert abrogated this supporting effect of MSC. Western blot analysis using phosphospecific antibodies demonstrated that direct cell-to-cell contact with MSC caused strong activation of Akt and STAT3 signaling in NB4 cells, which have low baseline phosphorylation of these proteins. Treatment with PI3K inhibitor LY294002 or JAK/STAT3 inhibitor (AG480) decreased both, Akt and STAT3 activation in NB4 cells, however, in cells co-cultured in direct contact with MSC the Akt and STAT3 phosphorylation levels were still significantly higher than in suspension cultures and in cells separated by transwell. These observations indicate cross-talk between PI3K/Akt and JAK/STAT pathways, and that Akt is activated independent from PI3K in NB4 cells through direct interaction with MSC. Both, LY294002 and AG480 induced apoptosis and decreased viability of suspension NB4 cells, but this effect was partially abrogated by MSC co-culture. Next, we examined the effects of these signal transduction inhibitors on MSC. MSC expressed both, phospho-Akt and phospho-Stat3, which was inhibited by LY294002 and AG480. LY294002 but not AG480 induced moderate apoptosis in MSC (annexin V positivity; MSC alone19.7 %; LY294002, 30.8%; AG480, 20.1% at 72 hours). Finally, we investigated Akt and STAT3 activation associated with ILK in NB4 cells. Treatment with ILK inhibitor KP004 (QLT Inc., Vancouver, Canada) decreased phosphorylation of Akt and STAT3 only in NB4 cells co-cultured with MSC and not in suspension cultures. The specific abrogation of MSC-mediated signaling resulted in higher induction of apoptosis in stroma co-cultured cells compared to suspension cells (annexin V positivity; KP004 treated suspension cultures 47.4±4.3%; MSC co-cultures 64.9±10.3%). These results indicate that bone marrow stroma cells support survival of leukemic cells through β integrin linked ILK, which activates Akt in a PI3K-independent manner and also stimulates STAT3. We propose that abrogation of ILK/Akt and STAT3 signaling may overcome protective effects of the bone marrow microenvironment on APL cells and thereby greatly enhance anti-leukemic therapies.

Identification Of Specific Hematopoietic Populations Present In Peripheral Blood Mononuclear Cells That Increase Erythroid Output Directly Or Through Feeder/Stromal Cell-Like Properties

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3414-3414
Author(s):  
Esther Heideveld ◽  
Valentina Tirelli ◽  
Francesca Masiello ◽  
Fatemehsadat Esteghamat ◽  
Nurcan Yagci ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Fold Increase ◽  
Cell Contact ◽  
Peripheral Blood Mononuclear ◽  
Effector Cells ◽  
Cd34 Cells ◽  
Blood Mononuclear Cells

Abstract Hematopoietic development occurs in defined niches that ensure specific interactions and cross-talk with the surrounding stromal cells and different hematopoietic cells themselves. For instance, erythropoiesis occurs on the macrophage island within the bone marrow and the central macrophage is believed to regulate pro-erythroblast differentiation, the final stages of enucleation and reticulocyte maturation. We have observed that the expansion of erythroblasts from total peripheral blood mononuclear cells is increased compared to CD34+ Hematopoietic Stem/Progenitor Cells (HS(P)C) isolated from the same amount of blood [van den Akker, Haematologica, 2010]. This suggests i) the presence of CD34-cells that contribute to erythropoiesis and/or ii) that cell-cell contact or specific secreted growth factors by “helper” cells in these cultures can regulate hematopoiesis/erythropoiesis to increase erythroblast yield. Identifying the specific population(s) underlying the increased erythroid yield and understanding their way of action and regulatory mechanism during HSC differentiation and erythropoiesis is not only important to improve erythroblast culture conditions but may also provide clues to the function of hematopoietic effector cells in the various HS(P)C/erythroblast niches. Using specific lineage depletion (among which CD3 and CD14) we have identified and quantified various human erythroid and non-erythroid CD34+ and CD34- populations on the basis of CD36 co-expression in peripheral blood mononuclear cells (PBMC). Erythroid outgrowth from these CD34- populations and CD34+ populations and their contribution to the total erythroid yield from PBMC was assessed. Interestingly, total erythroid yield from the individual sorted populations did not reach the erythroid yield obtained from total PBMC. We hypothesized that support/feeder cells present in total PBMC are positively influencing in vitro erythropoiesis. In agreement with this, PBMC immuno-depletion of specific hematopoietic cell types identified CD14 cells (monocyte/macrophages) and to a lesser extend CD3 cells (lymphocytes) to be also partly responsible for the increased erythroblast yield. Compared to HS(P)C alone, co-culture of CD14 cells and HS(P)C isolated from PBMC resulted in a 5-10 times increase in CD71high/CD235med erythroblasts. Conditioned medium of CD14 cells as well as transwell experiments reconstituted the effect of the HS(P)C-CD14 co-cultures to 70%-80%, indicating that cell-cell contact plays a minor role. CD14 cells could elicit their effect at different stages during HSPC/HSC differentiation to erythroblasts. Co-culture of CD14 cells with pro-erythroblasts did not increase the cellular yield or proliferation rate. In contrast, two days of CD14 co-culture with CD34+ cells results in a 5 fold increase of total colony forming units without altering the colony lineage dynamics. In agreement with this a 5 fold increase in CD34+ cells was observed. These results indicate that CD14 cells elicit their effect on early hematopoietic progenitors but not on the erythroblast population. The results predict that depletion of CD14+ cells from PBMC should result in a decrease in the total number of CD34+cells. Indeed, we observed a 2 fold decrease of specifically HS(P)Cs and MEPs after two days of culture in PBMCs depleted for CD14 cells. Taken together our data i) identify previously unrecognized erythroid and non erythroid CD34- and CD34+ populations in peripheral blood that contribute to erythroid yield from total PBMC and ii) indicate modulation of HS(P)C outgrowth by specific hematopioietic effector cells present in peripheral blood that can also be found near specific hematopoietic niches in the bone marrow. The involvement of CD3 and CD14 immune cells suggests that HS(P)C and erythropoiesis may be modulated by immune-responses. Disclosures: No relevant conflicts of interest to declare.

Detailed Safety Analysis of Venetoclax Combined with Rituximab in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2033-2033 ◽  
Author(s):  
Danielle M. Brander ◽  
Michael Y. Choi ◽  
Andrew W. Roberts ◽  
Shuo Ma ◽  
L. Leanne Lash ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Chronic Lymphocytic Leukemia ◽  
Board Of Directors ◽  
Peripheral Blood ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Advisory Committees ◽  
Grade 3 ◽  
Over Time

Abstract Background: Venetoclax (VEN) is a selective, potent, orally bioavailable BCL-2 inhibitor FDA-approved for patients with del(17p) chronic lymphocytic leukemia (CLL) and who have received ≥1 prior therapy. Based on preclinical evidence of synergy, VEN plus rituximab is being assessed in an ongoing Phase 1b study. Methods: Patients with relapsed/refractory (R/R) CLL received daily VEN with stepwise ramp-up over 3-4 weeks to reach daily doses of 200-600mg. After 1 week at the target dose, monthly rituximab was added for 6 doses. Responses and progression were assessed by iwCLL criteria with CT scan and bone marrow biopsy. Bone marrow assessments were done at screening, completion of combination therapy (month 7), and 2 months after clinical/radiologic criteria of iwCLL response were met. Minimal residual disease (MRD) was assessed in peripheral blood and marrow aspirates using ≥4 color flow cytometry (min sensitivity: 0.01%). Data cutoff was 04March2016, with analysis focusing on updated safety of cytopenias experienced on the course of treatment. Results: Forty-ninepatients enrolled (48 CLL/1 SLL). Patients had received a median of 2 prior therapies (range: 1-5) and disease in 25 (51%) was considered refractory to the most recent therapy. Median time on study was 28 (<1-42) months, with 31 patients active on study. Eighteen patients discontinued: 11 due to disease progression, 3 due to toxicity (peripheral neuropathy [1], MDS [1], and death due to TLS [1]), 3 withdrew consent, and 1 was lost to follow up. Across all doses, the most common AEs of any grade were diarrhea (57%), neutropenia (55%), upper respiratory tract infection (55%), and nausea (51%). Peripheral blood cytopenias were the most common Grade 3/4 AEs (neutropenia [53%], thrombocytopenia [16%], anemia [14%], febrile neutropenia [12%], and leukopenia [12%]). Twenty-seven (55%) patients had a history of neutropenia, of whom 6 were receiving G-CSF support prior to starting VEN. Overall, in the first month of therapy, 15 (31%) experienced an AE of neutropenia (any grade). Thereafter, the rate of new AEs of neutropenia decreased over time. While there was individual patient variability, mean ANC was stable over time. Overall, 26 (53%) patients had Grade 3/4 neutropenia. Neutropenia was generally well tolerated and managed by G-CSF support in 24 patients, in addition to ≥1 dose modification in 11 of the 24 patients. Of 8 (16%) patients who experienced grade 3 infections, 2 were while neutropenic. There were no grade 4 infections. Among the 11 (22%) patients who developed any-grade thrombocytopenia, none occurred within 2 weeks of a reported bleeding-related AE. One patient had thrombocytopenia overlapping with disease progression on therapy. Objective response rate for all patients was 86% (n=42), with 51% (n=25) who had complete response (CR/CRi; 12 achieved CR/CRi by month 7). At the completion of combination therapy (month 7), 39 patients had evaluable bone marrow assessments. Thirty (77%) had no histologic evidence of CLL in the bone marrow and 22 patients (56%) had attained bone marrow MRD-negativity. In longer follow up at any point during treatment for all 49 patients, 37 (75%) patients achieved complete marrow clearance and 28 (57%) achieved marrow MRD-negativity. Conclusions: Transient manageable neutropenia was the most common AE, with first onset usually seen within the first month of treatment and the onset of new neutropenia AEs decreased over time. No patients discontinued the study due to cytopenias. Patients were able to continue on study and high rates of response to treatment were observed. VEN given with rituximab achieved rapid and profound reductions in disease burden in peripheral blood and bone marrow. 77% of evaluable patients achieved morphologic clearance by month 7, and 57% were MRD-negative at any point on study. Figure 1 Figure 1. Disclosures Brander: TG Therapeutics: Research Funding; Gilead: Honoraria. Roberts:AbbVie: Research Funding; Servier: Research Funding; Janssen: Research Funding; Genentech: Research Funding; Genentech: Patents & Royalties: Employee of Walter and Eliza Hall Institute of Medical Research which receives milestone payments related to venetoclax. Ma:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Genentech: Consultancy, Honoraria, Speakers Bureau; Novartis: Research Funding; Xeme: Research Funding; AbbVie: Research Funding. Lash:AbbVie: Employment. Verdugo:AbbVie: Employment, Other: may own stock. Zhu:AbbVie Inc.: Employment, Other: may own stock. Kim:AbbVie: Employment. Seymour:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

scholarly journals Niche Recycling through Division-Independent Egress of Hematopoietic Stem Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 79-79
Author(s):  
Agnieszka Czechowicz ◽  
Deepta Bhattacharya ◽  
Lisa Ooi ◽  
Derrick J Rossi ◽  
David Bryder ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Normal Animal ◽  
Cell Types ◽  
Therapeutic Interventions ◽  
Wild Type ◽  
Advisory Committees ◽  
Hematopoietic Stem

Abstract Abstract 79 Hematopoietic stem cells (HSCs) are thought to reside in discrete niches through stable adhesion. However, previous studies through unfractionated bone marrow transplantation experiments, have suggested that host HSCs can be replaced by transplanted donor HSCs, even in the absence of cytoreductive conditioning. The need for ablating host HSCs prior to transplantation to achieve high levels of donor HSC engraftment has been a hotly debated issue over the years, with a number of groups claiming efficient HSC replacement in the absence of prior cytoreductive conditioning of the host, while experimental and clinical studies from our group and others found little evidence for extensive HSC replacement in unconditioned recipients. We specifically examined the intrinsic behavior and replacement properties of HSCs rather than that of unfractionated bone marrow, which contains a number of different cell types that have been reported to influence engraftment and replacement, such as host-reactive T cells and stromal cells. In order to study the physiologic properties of peripheral blood HSCs, we isolated KLS CD27+ IL-7Ra- CD150+ CD34- cells from peripheral blood and were the first to our knowledge to identify these cells as peripheral blood HSCs. We calculated then, through cell surface phenotyping and transplantation of unfractionated blood, that up to 1-5% of the total pool of HSCs enter into the circulation each day. Bromodeoxyuridine (BrdU) feeding of 3, 6, 9 and 12 days demonstrated that HSCs in the bone marrow incorporate BrdU at the same rate as do HSCs in the peripheral blood, suggesting that egress from the bone marrow to the blood can occur without cell division and can leave behind vacant HSC niches. Indeed, transplantation of over 10,000 purified HSCs, representing approximately 50% of the total number of HSCs in a normal animal, into unconditioned wild type mice led to the occupancy of 2-5% of the total number of appropriate niches by the donor HSCs, a similar percentage as was estimated for the fraction of HSCs that egress daily. Additionally, repetitive daily transplantations of small numbers of HSCs administered as new niches became available over the course of 7 days led to significantly higher levels of engraftment than did large single bolus transplantations of the same total number of HSCs. These data demonstrate that niche saturation following transplantation is transient and provide insight as to how HSC replacement can occur despite the residence of endogenous HSCs in niches. We, for the first time, have specifically assessed the number of available HSC niches in normal wild type animals and the rate of their emptying under steady-state conditions. Moreover, our study provides a model that is consistent with host HSC replacement following donor HSC transplantation in unconditioned recipients, yet is also consistent with data suggesting the existence of a physically discrete niche which effectively retains and regulates HSCs. Importantly these data suggest therapeutic interventions that capitalize upon physiological HSC egress, and allow for increased levels of HSC engraftment with non-myeloablative conditioning. Disclosures: Weissman: Affiliations that might be perceived to have biased this work are as follows: I.L.W. owns significant Amgen stock, cofounded and consulted for Systemix, is a cofounder and director of Stem Cells, Inc., and cofounded and is a director of Cellerant, Inc. Al: Employment, Research Funding; Affiliations that might be perceived to have biased this work are as follows: I.L.W. owns significant Amgen stock, cofounded and consulted for Systemix, is a cofounder and director of Stem Cells, Inc., and cofounded and is a director of Cellerant, Inc. Al: Consultancy; Affiliations that might be perceived to have biased this work are as follows: I.L.W. owns significant Amgen stock, cofounded and consulted for Systemix, is a cofounder and director of Stem Cells, Inc., and cofounded and is a director of Cellerant, Inc. Al: Equity Ownership; Affiliations that might be perceived to have biased this work are as follows: I.L.W. owns significant Amgen stock, cofounded and consulted for Systemix, is a cofounder and director of Stem Cells, Inc., and cofounded and is a director of Cellerant, Inc. Al: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Modulation of CD81 By Epigenetic Drug Combination Sensitizes Acute Lymphoblastic Leukemia Via Decreased BTK Signaling

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2628-2628
Author(s):  
Anthony Quagliano ◽  
Anilkumar Gopalakrishnapillai ◽  
E. Anders Kolb ◽  
Sonali Barwe
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Adhesion ◽  
Drug Combination ◽  
Fold Increase ◽  
Surface Expression ◽  
Cellular Adhesion ◽  
P53 Expression ◽  
Epigenetic Drug ◽  
Pre Treatment

Background We previously discovered that the epigenetic drug combination - azacitidine (aza, DNMTi) and panobinostat (pano, HDACi) can sensitize ALL cells to chemotherapy (Quagliano et al., Leuk Res, 44:101, 2017). This sensitization occurred through a decrease in cellular adhesion and a modulation of the cell surface expression of the tetraspanin protein CD81 (Quagliano et al., Blood, 132:3957, 2018). This study aims to elucidate the molecular mechanism by which CD81 surface modulation by pre-treatment with aza/pano leads to chemosensitization. Methods CD81 knockout Nalm6 (CD81KO) cells were generated by CRISPR/Cas9 mutagenesis. IHC was performed using anti-human mitochondria antibody on femurs harvested from NSG-SGM3 mice at 72 h post transplantation with WT or CD81KO cells. For adhesion assay, ALL cells stained with VPD450 were co-cultured with Saos-2 cells for 24 h. Unbound cells were washed, and bound cells were collected for flow cytometry analysis. CD19 surface expression was determined after 48 h treatment with aza/pano (500 nM/1.5 nM) using flow cytometry. For western blot analysis, aza/pano treated cells were transferred on to Saos-2 monolayers and treated with Ara-C (30 nM) for 16 h. Results CD81KO cells not only had decreased homing and engraftment visualized by reduced ALL cell presence in bone marrow (Fig. 1A), but also had 45% reduction in cellular adhesion to osteoblasts compared to WT Nalm6 cells (Fig. 1B), indicating that CD81 downregulation results in reduced bone marrow interactions. To investigate the signaling effects downstream of aza/pano-mediated CD81 modulation, we first tested if CD19 was affected due to its prominent role in the formation of the B-cell co-receptor and because CD19 requires CD81 for proper membrane trafficking (Cherukuri et al., J Immunol, 172:370, 2004). CD19 surface expression was reduced in aza/pano-treated cells and completely knocked out in CD81KO cells (Fig. 1C). CD19 is known to prolong and amplify the activation of Bruton's tyrosine kinase (BTK), so we also analyzed the phosphorylation of BTK in aza/pano-treated cells and found it to be reduced by 63% (Fig. 1D). This reduction in BTK phosphorylation may be responsible for the decrease in cell adhesion following treatment with aza/pano because prior studies observed reduced adhesion following BTK inhibition (Herman et al., Clin Cancer Res, 21:4642, 2015). Taken together, these data suggest that aza/pano induced reduction in cell adhesion was mediated by downregulation of CD81 and BTK dephosphorylation. We studied how the expression of p53 and its target BCL2 associated X protein (BAX), which are known to be induced by Ara-C, were affected following pre-treatment with aza/pano. Cells with Ara-C treatment alone or the aza/pano pre-treatment both had minor induction of p53 expression compared to control, while aza/pano pre-treated cells that received Ara-C had further increase in p53 protein (1.7-fold increase compared to Ara-C alone, Fig. 1E). Bax mRNA and protein were increased 4.2-fold in aza/pano-treated cells following Ara-C treatment compared to Ara-C alone. Increased Bax expression following Ara-C treatment in aza/pano pre-treated cells was accompanied by a 3.9-fold increase in cleavage of caspase-3 compared to cells treated with Ara-C alone, which in turn causes cleavage of Poly-ADP Ribose Polymerase (PARP) (Fig. 1E). Both p53 and Bax protein levels were higher in CD81KO cells than in WT cells (Fig. 1E), suggesting that aza/pano-mediated reduction of CD81 is involved in inducing the expression of p53. CD81KO cells that were treated with Ara-C also had further increase in p53 and Bax expression compared to Ara-C treated WT cells (Fig. 1E), consistent with an increased sensitivity to chemotherapy. To confirm the role of BTK inhibition in the induction of p53, Nalm6 cells were treated with the BTK inhibitor fenebrutinib for 24 h (10 nM). Following treatment, expression of p53 was induced and Bax expression was 2.6-fold higher in treated cells compared to untreated cells (Fig. 1E). Taken together, these data suggest that modulation of the surface expression of CD81 and the phosphorylation of BTK by aza/pano induces sensitization via upregulation of p53 and overexpression of Bax. Conclusion We identify a novel mechanism by which aza/pano treatment induces chemosensitization by reducing cell adhesion via modulating CD81 surface expression, reducing BTK phosphorylation, and inducing p53. Figure 1 Disclosures No relevant conflicts of interest to declare.

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