Characterization of Platelet Activation in Patients with Eisenmenger Syndrome

Abstract Background Eisenmenger Syndrome (ES) is an extremely rare and serious complication of congenital heart disease in which pulmonary vascular resistance overcomes that of the systemic circulation causing bidirectional or reversed flow across an intracardiac shunt. Patients with ES have an increased incidence of both thrombotic and bleeding complications which occur through poorly understood mechanisms. We have recently demonstrated a critical mechanistic role for platelets in supporting abnormal hypercoagulability in patients with ES using calibrated automated thrombography (Kevane & Ní Áinle et al., J Thromb Haemost 2018). Aims Based upon our published data, we further hypothesized that patients with ES would have higher plasma concentrations of platelet activation markers. Therefore, the aim of this study was to measure plamsa levels of soluble P-Selectin (sP-Selectin) and soluble glycoprotein VI (sGPVI) in patients with ES and in matched healthy controls. Methods Patients over the age of 18 with Eisenmenger Syndrome and healthy controls were recruited from the cardiology service at a large tertiary referral centre (Mater Misericordiae University Hospital) incorporating the Irish national congenital heart disease service. Platelet poor plasma (PPP) was generated from participants' blood by centrifugation at 2000xg for 10 minutes at room temperature. Commercially available ELISA assays employing quantitative sandwich immunoassay techniques were performed according to manufacturer protocol to measure plasma sP-Selectin and sGPVI levels. All experiments were performed in duplicate with results expressed as mean +/- standard error of mean. Comparisons between groups were made utilising the Student's t-test with a p-value < 0.05 deemed to represent statistical significance. Results During the study period, >14,000 patients attended the MMUH cardiology service. Of these, 14 consecutive patients with a diagnosis of ES and 10 matched healthy controls were recruited. Patients with ES had significantly elevated plasma concentrations of both soluble P-Selectin [38.5 +/- 8.3 vs. 11.3 +/- 4.2 ng/ml (p < 0.05)] and soluble GPVI [10.5 +/- 2.4 vs. 1.5 +/- 1.4 ng/ml (p < 0.01)] compared to healthy controls. Conclusion Building upon our recently published data in this population, a large cohort given the extreme rarity of this condition, increased concentrations of markers of platelet activation in individuals with ES further suggest a mechanistic role for platelets in ES-mediated hypercoagulability. This phenotype may be a consequence of vascular pathology associated with pulmonary hypertension in these patients. As such, therapies targeted at underlying vascular pathologies may act to ameliorate prothrombotic tendencies and we aim to characterize response to therapy during this ongoing study. Disclosures Ni Ainle: Leo Pharma: Research Funding; Actelion: Research Funding; Bayer: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Boehringer: Membership on an entity's Board of Directors or advisory committees.

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Increased Soluble GPVI Levels in Cirrhosis: Evidence for Collagen Induced Platelet Activation In Vivo

Blood ◽

10.1182/blood.v126.23.1114.1114 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1114-1114

Author(s):

Karl Egan ◽

Eimear Dunne ◽

Audrey Dillon ◽

Barry Kevane ◽

Zita Galvin ◽

...

Keyword(s):

Liver Disease ◽

Board Of Directors ◽

Platelet Activation ◽

Research Funding ◽

Decompensated Cirrhosis ◽

Dependent Manner ◽

Healthy Controls ◽

Advisory Committees ◽

Significant Difference

Abstract Background Cirrhosis is a consequence of prolonged inflammation arising from chronic liver disease of different aetiologies. It is characterised by tissue fibrosis, the deposition of collagen-rich extracellular matrix tissue within the liver. Glycoprotein VI (GPVI) is platelet-specific collagen receptor that is shed from the platelet surface in a metalloproteinase-dependent manner in response to GPVI ligation. The shed extracellular region of GPVI can be detected in plasma and used as a measure of GPVI-dependent platelet activation in vivo. Several lines of evidence suggest that GPVI-dependent platelet activation occurs in cirrhosis. Platelets have been shown to accumulate at sites of collagen-rich fibrotic tissue. Circulating levels of collagen are increased in cirrhosis. Collagen-induced platelet aggregation responses are reduced in vitro with cirrhosis. Based on these results, we hypothesised that soluble GPVI (sGPVI) levels are increased in patients with cirrhosis. As such, the aim of this study was to quantify sGPVI levels in patients with cirrhosis and compare to healthy controls. Methods Compensated cirrhotic patients were recruited at the Mater Misericordiae University Hospital, Dublin, Ireland. The diagnosis of cirrhosis was based on clinical examination, blood tests, and radiological examination (nodular surface, larger right lobe, coarse echotexture). Exclusion criteria were decompensated cirrhosis, recent thrombotic events, and antiplatelet and/or anticoagulant therapies. Healthy controls were recruited at the Royal College of Surgeons in Ireland and Beaumont Hospital, Dublin, Ireland. Blood samples were collected into vacutainers containing 3.2 % sodium citrate as anticoagulant. sGPVI levels in platelet poor plasma were measured using an in house custom ELISA. Results 57 patients with mixed aetiology cirrhosis and 55 healthy controls were recruited. In the patient group, 42% of patients had alcoholic liver disease (ALD), 30% had hepatitis C (HCV), 7% had non alcoholic fatty liver disease (NAFLD), 5% had Hepatitis B (HBV), 5% had autoimmune hepatitis (AIH), 5% had cryptogenic liver disease, 4% had hereditary haemochromatosis (HH), and 2% had primary biliary cholangitis (PBC). sGPVI levels were significantly increased in patients with cirrhosis (5.8 ± 0.6 ng/ml, n = 57) compared to healthy controls (3.2 ± 0.4 ng/ml, n = 55, p < 0.0001). There was no significant difference between sGPVI levels in AIH (4 ± 1 ng/ml, n = 3), ALD (5.6 ± 1 ng/ml, n = 24), cryptogenic (12 ± 5 ng/ml, n = 3), HBV (3.1 ± 1 ng/ml, n = 3), HCV (5 ± 0.6 ng/ml), or NAFLD (5.3 ± 1.1 ng/ml, n = 4). sGPVI levels did not correlate with platelet count (r = 0.12, p = 0.3) or parameters of liver cell function (albumin, bilirubin, prothrombin time, and liver stiffness measurements). Conclusion sGPVI levels are significantly increased in patients with mixed aetiology cirrhosis. This indicates collagen induced platelet activation is occurring in vivo and suggests the presence of an underlying coagulopathy in patients with cirrhosis. Disclosures Ní Áinle: Actelion Pharma: Research Funding; Leo Pharma: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees.

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Genomic and Transcriptomic Differences of Myelodysplastic Syndrome/Myeloproliferative Neoplasm with Ring Sideroblasts and Thrombocytosis (MDS/MPN-RS-T) and Myelodysplastic Syndrome with Ring Sideroblasts (MDS-RS)

Blood ◽

10.1182/blood-2020-139983 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 18-19

Author(s):

Guillermo Montalban Bravo ◽

Rashmi Kanagal-Shamanna ◽

Faezeh Darbaniyan ◽

Irene Ganan-Gomez ◽

Koji Sasaki ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Myeloproliferative Neoplasm ◽

Enrichment Analysis ◽

Cytokine Signaling ◽

Healthy Controls ◽

Kinase Signaling ◽

Advisory Committees ◽

Ring Sideroblasts

INTRODUCTION: Myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is a rare hematological disorder characterized by anemia, bone marrow dysplasia with ring sideroblasts and persistent thrombocytosis, and high frequency of SF3B1 and JAK2 mutations. Despite clinical, histological and molecular similarities with MDS with ring sideroblasts (MDS-RS), the clinical outcomes of these entities are diverse. To date, there is no data evaluating specific functional pathways which might explain phenotypic and clinical differences beyond diverse frequencies of JAK2 mutation. METHODS: We evaluated a total of 24 patients (pts) with MDS/MPN-RS-T and 27 pts with MDS-RS. Diagnosis was based on WHO 2017 criteria and confirmed by two independent hematopathologists. Whole bone marrow DNA was subject to 81 gene targeted next-generation sequencing (NGS) analysis. CD34+ cells from bone marrow samples of 4 pts with MDS/MPN-RS-T, 7 pts with MDS-RS and 17 healthy individuals obtained from AllCells (Emeryville, CA) were isolated using the CD34 MicroBead Kit and RNA was isolated using the PicoPure RNA isolation kit. Fastq files were mapped to the human genome (build GRCh38) in TopHat2 using the default options. Differential gene expression analysis was conducted using DESeq2 in R version 3.6.2. Pathway enrichment analysis was performed using gene set enrichment analysis, with the fgsea library in R. RESULTS: Patients with MDS/MPN-RS-T had higher median bone marrow ring sideroblast percentage (47% vs 32%, p=0.04) and absolute neutrophil count (4.34x109/L vs 2.99x109/L, p=0.001). Frequency of identified mutations and their VAFs compared to MDS-RS are shown in Figure 1A. The median number of mutations was higher in MDS/MPN-RS-T than in MDS-RS (3 vs 2, p<0.001). SF3B1 mutations were the most frequent in both entities (MDS/MPN-RS-T: 92%, MDS-RS: 82%), had similar median VAF (34% vs 32%, p=0.619), and involved the hot spot codon K700E in 64% and 43% of MDS-RS and MDS/MPN-RS-T (p=0.227), respectively. As expected, 58% of pts with MDS/MPN-RS-T had JAK2 V617F mutations but were also more likely to have mutations in kinase signaling genes (NF1, SETBP1, CBL, CBLB, FLT3 TKD, MPL) compared to MDS-RS (29% vs 4%, p=0.019). Four (40%) of JAK2 negative MDS/MPN-RS-T had mutations in kinase signaling genes. There were no differences in frequency of TET2 mutations between both entities. However, there was a trend for the median VAF of TET2 mutations in MDS/MPN-RS-T to be lower than in MDS-RS (1.5% vs 21.1%, p=0.177) suggesting a likely subclonal nature of these mutations compared to MDS-RS in which they appeared as dominant events. MDS/MPN-RS-T showed distinct transcriptomic profile compared to both healthy controls and MDS-RS. Compared to healthy controls, a total of 2 pathways were significantly upregulated and 58 were downregulated in MDS/MPN-RS-T while 5 pathways were upregulated and 69 were downregulated in MDS-RS. Compared to MDS-RS, a total of 29 pathways were significantly upregulated and 26 were downregulated in MDS/MPN-RS-T. The most significantly upregulated pathways in MDS/MPN-RS-T included genes involved in platelet activation and aggregation, cytokine signaling, and signaling through GPC receptors (Figure 1C). Compared to both healthy control and MDS-RS, MDS/MPN-RS-T was characterized by downregulation of genes involved in DNA damage response, regulation of apoptosis, telomere maintenance and RNA synthesis (Figure 1D). MDS-RS was characterized by downregulation of genes involved in signaling by GPC receptors and MAPK signaling, mRNA splicing, cytokine signaling and signaling through interleukins compared to both control and MDS/MPN-RS-T (Figure 1C). CONCLUSIONS: MDS/MPN-RS-T is characterized by co-dominance of SF3B1 and JAK2 mutations and presence of minor kinase signaling mutations not observed in MDS-RS. Upregulation of cytokine and interleukin signaling mediated through GPC receptors, and downregulation of genes involved in apoptosis and DNA damage are unique transcriptomic features of MDS/MPN-RS-T likely driven by genotype. These unique genomic and transcriptomic characteristics of MDS/MPN-RS-T supports the classification of MDS/MPN-RS-T based on genomic features beyond presence of SF3B1 mutation, and might represent potential therapeutic avenues for this rare disease. Figure Disclosures Sasaki: Otsuka: Honoraria; Pfizer Japan: Consultancy; Novartis: Consultancy, Research Funding; Daiichi Sankyo: Consultancy. Kantarjian:Sanofi: Research Funding; Abbvie: Honoraria, Research Funding; Janssen: Honoraria; BMS: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive biotechnologies: Honoraria; Aptitute Health: Honoraria; Immunogen: Research Funding; Jazz: Research Funding; Daiichi-Sankyo: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; BioAscend: Honoraria; Novartis: Honoraria, Research Funding; Delta Fly: Honoraria; Pfizer: Honoraria, Research Funding; Oxford Biomedical: Honoraria; Ascentage: Research Funding. Garcia-Manero:Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amphivena Therapeutics: Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding; Onconova: Research Funding; Merck: Research Funding; Novartis: Research Funding; H3 Biomedicine: Research Funding; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy.

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Iron Overload Diminishes the Effectiveness of the Innate Immune Response in Thalassemia Major: a Possible Mechanism for Increased Infection Risk.

Blood ◽

10.1182/blood.v114.22.4071.4071 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4071-4071

Author(s):

Patrick B Walter ◽

Paul R Harmatz ◽

Annie Higa ◽

David Killilea ◽

Nancy Sweeters ◽

...

Keyword(s):

Flow Cytometry ◽

Immune Response ◽

Iron Overload ◽

Board Of Directors ◽

Innate Immune Response ◽

Research Funding ◽

Innate Immune ◽

Healthy Controls ◽

Advisory Committees ◽

Fluorescent Intensity

Abstract Abstract 4071 Poster Board III-1006 Introduction Infection is the second most common cause of death in thalassemia. The innate immune system provides a first line of defense against infection and specificity depends on pattern recognition receptors (PRRs) specific to microbial pathogens. One class of PRR called the toll-like receptors (TLRs) are important for transducing the signal for bacterial Lipopolysaccharide (LPS), resulting not only in cytokine production, but also in the control of extracellular iron levels through production of neutrophil gelatinase associated Lipocalin (NGAL). However, the exact role that NGAL plays and the expression level of PRRs are unknown in thalassemia. Thus, the goal in these studies is to investigate the relationship of iron overload to the innate immune cell expression of PRRs and NGAL in thalassemia. Patients and Methods Fifteen transfusion dependent thalassemia patients (11 – 29 yrs old) participating in the combination trial of deferasirox (an oral iron chelator) and deferoxamine were enrolled (Novartis sponsored CICL670AUS24T). Fasting blood samples were obtained i) at baseline after a 72 hr washout of chelator, and ii) at 6 and 12 months on study. Five healthy controls (13 - 18 yrs old) were also enrolled. Fresh monocytes were isolated using antibody-linked magnetic microbeads (Miltenyi Biotec Inc). Highly enriched populations of CD14+ monocytes were verified by flow cytometry. The expression of TLR4, also examined by flow cytometry is reported as the mean fluorescent intensity (MFI). In patients with thalassemia, liver iron concentration (LIC) was analyzed by biomagnetic susceptibility (“SQUID”, Ferritometer®). The plasma levels of NGAL were analyzed by ELISA. Results At baseline the expression of monocyte TLR4 (mean 18.8 ± 3.5 MFI) was reduced 30% compared to the healthy controls (mean 26.9 ± 7.6 MFI, p<0.05). The expression of TLR4 over the follow-up period of 52 weeks in patients receiving intensive combination chelator therapy significantly increased 27% / year (7 MFI / year, p=0.005). Interestingly the expression of monocyte TLR4 was negatively correlated with LIC (r=-0.6, p=0.04). Finally, thalassemia patients at baseline have significantly higher levels of NGAL (80 ± 20 ng/ml) compared to controls (42 ± 15 ng/ml, p=0.01). Conclusions These preliminary studies support the hypothesis that iron burden has a negative impact on the innate immune response in thalassemia as demonstrated by the decreased expression of TLR4. After intensive chelation, the levels of TLR4 increased, indicating that decreased iron overload with chelation may improve innate immune responsiveness. Finally, the iron transport protein NGAL is significantly elevated in thalassemia possibly acting to prevent essential iron uptake by pathogenic bacteria. Disclosures: Harmatz: Novartis: Research Funding; Apotex : Membership on an entity's Board of Directors or advisory committees; Ferrokin: Membership on an entity's Board of Directors or advisory committees. Vichinsky:Novartis: Consultancy, Research Funding.

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The Pan Histone Deacetylase Inhibitor Panobinostat and the Iso-Selective Inhibitor Romidepsin Reduce Glycoprotein VI Expression and Inhibit Platelet Activation in Response to Collagen Related Peptide

Blood ◽

10.1182/blood.v118.21.1154.1154 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1154-1154

Author(s):

Mark J Bishton ◽

Miles Prince ◽

Ricky W Johnstone ◽

Simon J. Harrison ◽

Benjamin T. Kile

Keyword(s):

Board Of Directors ◽

Histone Deacetylase ◽

Platelet Activation ◽

Western Blotting ◽

Research Funding ◽

Histone Deacetylase Inhibitors ◽

Surface Expression ◽

Selective Inhibitor ◽

Advisory Committees ◽

Related Peptide

Abstract Abstract 1154 Histone deacetylase inhibitors (HDACi) are anti-cancer drugs able to induce chromatin remodelling, alter gene expression and affect function of non-histone proteins. We recently reported that the pan-HDACi panobinostat and the iso-selective inhibitor romidepsin induce thrombocytopenia by reducing megakaryocyte proplatelet number, without effects on platelet half life (Bishton et al Blood 2011). The effect of HDACis on platelet function remains unknown, and we postulated possible interference with the expression or function of key platelet activating proteins. Platelet Glycoprotein (GP) VI is a member of the immunoglobulin superfamily, expressed exclusively on the surface of platelets and megakaryocytes, complexed with FcR g-chain dimers, predominantly responsible for adhesion of platelets to collagen. Following interaction with sub-endothelial collagen, the Src family kinases Fyn and Lyn mediate the recruitment and autophosphorylation of Syk kinase and thereby downstream signalling and platelet activation. Following the treatment of C57BL/6 mice with 10mg/kg panobinostat or 1mg/kg romidepsin intraperitoneally (IP) daily for three days, we isolated washed murine platelets for function testing. Following stimulation with thrombin, a dose-dependant increase was seen in platelet surface expression of CD62P (P-selectin), and also the conformationally active form of the integrin αIIbbIIIa, with no difference seen between groups. When collagen related peptide (CRP) was used as a platelet agonist, and activation assessed by p-selectin and activated αIIbbIIIa expression, platelets from cohorts of mice treated with panobinostat or romidepsin failed to increase the expression of either molecule in response to CRP, compared to vehicle treated mice. Co-treatment of mice with the murine thrombopoietin mimetic, AMP-4, or the proteasome inhibitor bortezomib did not alter effects of the HDACi. Ex vivo addition of panobinostat or romidepsin to naïve platelets did not however affect platelet activation, suggesting megakaryocytes rather than platelets to be the target cell responsible for these effects. Flow cytometric analysis of the expression of GPVI on platelets showed a consistent and statistically significant decrease in the median fluorescent intensity (MFI) of staining seen in both HDACi treated groups. No equivalent changes in the surface expression of the other collagen receptor integrin α2b1 were seen. Western blotting of murine platelets confirmed this reduction in GPVI and a ∼17kDa fragment was also seen with HDACi treated platelets, suggesting GPVI degradation. Following stimulation with CRP, Western blotting of platelets with a phospho-syk antibody showed a reduction in phospho-syk levels in platelets from mice treated with HDACi, consistent with decreased downstream signalling from the GPVI receptor. Western blotting of murine megakaryocytes differentiated from murine fetal liver cells by TPO, also demonstrated a reduction in GPVI expression following HDACi exposure, again suggesting an intrinsic megakaryocyte process to be responsible. qRT-PCR on HDACi treated megakaryocytes demonstrated a mild increase in GPVI mRNA levels post romidepsin, but no changes post panobinostat compared to vehicle treated cells, confirming transcriptional repression not to be responsible for these changes. We show that HDACi cause a reduction in surface expression of GPVI expression by inducing its degradation and thus inhibiting murine platelet responses to CRP. There was no evidence of an effect on gene transcription. Our work suggests a potential beneficial anti-thrombotic effect of HDACi, mediated by reduction in both platelet number and function. These findings support the need to investigate the role of HDACi and their effect on GPVI in myeloproliferative neoplasms particularly with respect to their impact on thrombotic complications. Disclosures: Off Label Use: Panobinostat and romidepsin are histone deacetylase inhibitors. We show that both reduce platelet response to collagen and therefore may have an anti-thrombotic effect. Prince:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Johnstone:N: Research Funding. Harrison:Cellgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding.

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Bone Marrow Hematopoietic Dysfunction in Untreated Chronic Lymphocytic Leukemia Is Partially Mediated By Exposure to Constituents of the Leukemic Microenvironment

Blood ◽

10.1182/blood-2018-99-118916 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3132-3132

Author(s):

Bryce Manso ◽

Kimberly Gwin ◽

Charla R Secreto ◽

Henan Zhang ◽

Wei Ding ◽

...

Keyword(s):

Bone Marrow ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

Board Of Directors ◽

Research Funding ◽

Lymphocytic Leukemia ◽

Healthy Controls ◽

Advisory Committees ◽

The Impact

Abstract Peripheral immune dysfunction in B-Chronic Lymphocytic Leukemia (CLL) is well-studied and likely relates to the incidence of serious recurrent infections and second malignancies that plague CLL patients. However, the current paradigms of known immune abnormalities are not able to consistently explain these complications and it is not easy to correct CLL patient immune status. Here, we expand on our preliminary reports that demonstrate bone marrow (BM) hematopoietic dysfunction in early and late stage untreated CLL patients. We found reduced short-term functional capacity of hematopoietic progenitors in BM using colony forming unit assays (Figure 1A-C) and flow cytometry revealed significant reductions in frequencies of hematopoietic stem and progenitor cell (HSPC) populations (exemplified by Lin-CD34+ HSPCs, Figure 1D). We further report that protein levels of the transcriptional regulators HIF-1α, GATA-1, PU.1, and GATA-2 are overexpressed in distinct HSPC subsets from CLL patient BM, providing molecular insight into the basis of HSPC dysfunction. Interestingly, sustained myelopoiesis, evaluated by limiting dilution analysis in long-term culture-initiating cell (LTC-IC) assays maintained for five weeks, revealed no difference between healthy controls and CLL patients. These new data indicate that when HSPCs are removed from the leukemic microenvironment for ample in vitro culture time, they recover the ability to sustain myelopoiesis. To further assess the impact of the CLL microenvironment on HSPC biology, isolated HSPCs (CD34+ BM cells) from healthy controls were exposed in vitro to known leukemic microenvironment constituents. Exposure to TNFα, a cytokine constitutively produced by CLL B cells, resulted in rapid increases in PU.1 and GATA-2 proteins (Figure 2A-D). Similarly, addition of TNFα to the LTC-IC assay resulted in a striking ablation of myelopoiesis, even at the highest input cell concentration. Further, overexpression of PU.1 and GATA-2 were observed in HSPCs following co-culture with CLL B cells, a result that was not recapitulated when cells were exposed to IL-10, another cytokine constitutively produced by CLL B cells. These findings indicate specific components of the leukemic microenvironment are involved in HSPC modulation. Together, these findings expand on our previous observations of BM hematopoietic dysfunction in untreated CLL patients and offer new molecular insights into the contribution of the leukemic microenvironment on immunodeficiency in CLL. Disclosures Ding: Merck: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; Janssen: Research Funding; Abbvie: Honoraria, Research Funding; Gilead: Honoraria; AstraZeneca: Honoraria, Research Funding. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Prospective Study Reveals Increased Platelet Function Associated with Multiple Myeloma and Its Treatment

Blood ◽

10.1182/blood-2020-140821 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 21-21

Author(s):

Dalia Khan ◽

Joanne Mitchell ◽

Rekha Rana ◽

Neline Kriek ◽

Amanda Unsworth ◽

...

Keyword(s):

Multiple Myeloma ◽

Board Of Directors ◽

Platelet Function ◽

Research Funding ◽

Platelet Reactivity ◽

Immunoblot Analysis ◽

Healthy Controls ◽

Advisory Committees ◽

Fibrinogen Binding ◽

The Impact

Background: Multiple Myeloma (MM) is a rare incurable bone marrow cancer characterised by a malignant proliferation of plasma cells. MM is usually preceded by a premalignant and benign Monoclonal Gammopathy of Undetermined Significance (MGUS). The incidence of arterial and venous thrombosis in MM is substantially higher than in the normal population, however the cause of this increased thrombosis risk and the impact of MM on platelet function is unclear. Treatments for both newly diagnosed and relapsed/refractory patients with MM include Immunomodulatory drugs (IMiDs) such as thalidomide/lenalidomide-based combinations. These treatments improve considerably patient outcomes, however iMiD treatment also increases the risk of thrombotic complications in these patients. Aims: In this prospective study we explored the impact of MM and its treatment on platelet function. Methods: High throughput functional analysis was performed using platelets from normal healthy controls (n=31) and patients with MGUS (n=18), smouldering multiple myeloma (SMM, n= 20), and MM (26). The MM group was further divided into 3 treatment cohorts; (1) no treatment, (2) treatment with proteasome inhibitor (PI) and dexamethasone (Dex), and (3) treatment with PI, Dex, immunomodulatory drug (iMiD) and direct oral anticoagulant. Platelet aggregation and activation (fibrinogen binding and P-selectin exposure) were measured in response to a concentration range of agonists including ADP, the thrombin receptor agonist TRAP-6, collagen, collagen-related peptide (CRP), a thromboxane receptor agonist U46619 and epinephrine. Cereblon protein was detected in platelet protein extracts by immunoblot analysis. Results: Consistent with previous reports, modestly increased VWF and factor VIII levels were detected in MM patients, but no additional differences in coagulation parameters were detected in patient groups compared to normal healthy controls (other than expected due to anticoagulant usage). Platelet aggregation in response to each agonist was increased significantly in the MM patient group compared to the normal healthy controls, suggesting that platelet reactivity is elevated in MM patients through a common mechanism that is shared by different activation pathways or the involvement of multiple mechanisms. P-selectin exposure on platelets from MM patients was not significantly different from normal healthy donors, indicating that enhanced platelet reactivity in MM is specifically through modulation of integrin αIIbβ3 activation, fibrinogen binding and therefore enhanced aggregation. The effects of treatment on platelet function in patients on iMiD vs. non iMiD treatment were assessed. In the iMiD treatment group, patient platelets aggregated in response to lower concentrations of ADP, collagen, epinephrine and CRP in samples taken post-treatment compared to those taken before and during treatment. This demonstrates an increased sensitivity to platelet activation in these patients induced by treatment. Immunoblot analysis revealed that platelets contain cereblon, a therapeutic target of lenalidomide. The potential direct effects of iMiDs on platelets in vitro was therefore explored. Lenalidomide treatment (10mM) increased the ability of platelets to aggregate in response to low concentrations of each agonist tested when compared to normal controls. Conclusions: Platelet reactivity is increased in multiple myeloma and increased further upon iMiD treatment. The presence of the key therapeutic target for iMiDs in platelets and the ability of lenalidomide to modulate platelet function directly, reveals new avenues for investigation to determine the underlying mechanism of action. Disclosures Laffan: CSL: Consultancy; Pfizer: Consultancy; Sobi: Consultancy; Roche: Consultancy; LFB: Consultancy; Shire: Consultancy; Octapharma: Consultancy; Bayer: Speakers Bureau; Roche-Chugai: Speakers Bureau; Takeda: Speakers Bureau; Leo-Pharma: Speakers Bureau; Pfizer: Speakers Bureau. Shapiro:Bayer: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; NovoNordisk: Consultancy, Speakers Bureau; Sobi: Consultancy, Speakers Bureau; Chugai/Roche: Consultancy, Speakers Bureau; Shire/Takeda: Consultancy, Speakers Bureau. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ramasamy:Takeda: Research Funding; Janssen: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding; Amgen: Research Funding; Amgen: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Oncopeptides: Honoraria; Takeda: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Bristol Myers Squibb: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol Myers squibb: Membership on an entity's Board of Directors or advisory committees. Gibbins:Bristol Myers Squibb: Research Funding; Arena Pharmaceuticals: Research Funding.

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Synergistic Role of Leukemic and Non-Leukemic Immune Repertoires in CD8+ T-Cell Large Granular Lymphocytic Leukemia As Identified By Single-Cell Transcriptomics

Blood ◽

10.1182/blood-2021-146539 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1318-1318

Author(s):

Dipabarna Bhattacharya ◽

Jani Huuhtanen ◽

Matti Kankainen ◽

Tapio Lönnberg ◽

Cassandra M Kerr ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Lymphocytic Leukemia ◽

Leukemic Cells ◽

Healthy Controls ◽

Advisory Committees ◽

Cell Clones ◽

Tcr Repertoire

Abstract Background: T-cell large granular lymphocytic leukemia (T-LGLL), a rare lymphoproliferative disorder of mature T cells, is characterized by the accumulation of activated effector T cells leading to a clonally restricted T-cell receptor (TCR) repertoire. Chronic antigen stimulation together with activating somatic STAT3 mutations have been proposed to lead to clonal expansion of leukemic cells. However, no holistic research has been done to show how leukemic and non-leukemic cells liaise to sustain abnormal immune reactivity in T-LGLL. Methods: We investigated the transcriptome and TCR repertoire in T-LGLL using: 1) single-cell RNA and TCR (scRNA+TCRαβ) sequencing from CD45+ sorted blood cells (T-LGLL n=11, healthy n=6), 2) TCRβ sequencing from blood mononuclear cells (T-LGLL n=48, healthy n=823), 3) bulk RNA sequencing (T-LGLL n=15, healthy n=5), 4) plasma cytokine profiling (T-LGLL n=9, healthy n=9), and 5) flow cytometry validations (T-LGLL n=6, healthy n=6) (Figure) Results: ScRNA+TCRαβ-seq data revealed that in healthy controls, hyperexpanded CD8+ T-cell clones (at least 10 cells with identical TCRs) preferentially had an effector memory phenotype, whereas in T-LGLL, the hyperexpanded clonotypes represented a more cytotoxic (increased expression of GZMB, PRF1, KLRB1) and exhausted (LAG3 and TIGIT) phenotype. Using flow cytometry, we confirmed that upon anti-CD3/CD28/CD49 antibody stimulation, T-LGLL clones (CD8+CD57+) expressed higher levels of cytotoxic proteins (GZMA /GZMB , PRF1) but were deficient in degranulation responses and cytokine secretion as measured by expression of CD107a/b and TNFα/IFNγ, respectively. Focused re-clustering of the extracted T-LGLL clones from the scRNA+TCRαβ-seq data revealed considerable heterogeneity among the T-LGLL clones and partly separated the mutated (mt) STAT3 and wild type (wt) STAT3 clones. STAT3wt clones upregulated T-cell activation and TCR signaling pathways, with a higher cytotoxicity and lower exhaustion score as compared to STAT3mt clones. This was validated with bulk RNA-seq data. To understand the antigen specificities of the T-LGLL clones, we combined previously profiled T-LGLL TCRs with our data to form the largest described dataset of 200 T-LGLL clones from 170 patients. Notably, T-LGLL clones were found to be private to each patient. Furthermore, the analysis by GLIPH2 algorithm grouping TCRs did not reveal detectable structural similarities, suggesting the absence of a unifying antigen in T-LGLL. However, in 67% of T-LGLL patients, the TCRs of leukemic clones shared amino acid level similarities with the rest of the non-leukemic TCR repertoire suggesting that the clonal and non-clonal immune repertoires are connected via common target antigens. To analyze the non-clonal immune repertoire in T-LGLL in detail, we compared our data to other published scRNAseq data from solid tumors (n=4) and hematologic cancers (n=8) and healthy controls (n=6). The analysis revealed that in T-LGLL also the non-leukemic CD8+ and CD4+ T cells were more mature, cytotoxic, and clonally restricted. When compared to healthy controls and other cancer patients, in non-leukemic T-LGLL the most upregulated pathway was IFNγ response. Finally, most of the upregulated cytokines in T-LGLL (e.g., CCL2/3/7, CXCL10/11, IL15RA) were secreted predominantly by monocytes and dendritic cells, which also had upregulated HLA class II expression and enhanced scavenging potential in T-LGLL patients. Ligand-receptor analysis with CellPhoneDB revealed that the number of predicted cell-cell interactions was significantly higher in T-LGLL as compared to reactive T-cell clones in healthy controls. The most co-stimulatory interactions (e.g., CD2-CD58, TNFSF14-TNFRSF14) occurred between the IFNγ secreting T-LGLL clones and the pro-inflammatory cytokine secreting monocytes. Conclusions: Our study shows a synergistic interplay between the leukemic and non-leukemic immune cell repertoires in T-LGLL, where an aberrant antigen-driven immune response including hyperexpanded CD8+ T-LGLL cells, non-leukemic CD8+ cells, CD4+ cells, and monocytes contribute to the persistence of the T-LGLL clones. Our results provide a rationale to prioritize therapies that target the entire immune repertoire and not only the T-LGLL clones in patients with T-LGLL. Figure 1 Figure 1. Disclosures Loughran: Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioniz Therapeutics: Membership on an entity's Board of Directors or advisory committees; Keystone Nano: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Maciejewski: Alexion: Consultancy; Novartis: Consultancy; Regeneron: Consultancy; Bristol Myers Squibb/Celgene: Consultancy. Mustjoki: Novartis: Research Funding; BMS: Research Funding; Janpix: Research Funding; Pfizer: Research Funding.

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Dose Escalation Study of BET Inhibitor PLX2853 in Patients with Relapsed or Refractory Acute Myeloid Leukemia or High Risk Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2019-127497 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1391-1391 ◽

Cited By ~ 1

Author(s):

Naveen Pemmaraju ◽

Uma Borate ◽

Melhem Solh ◽

Gautam M. Borthakur ◽

Amy E. DeZern ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Plasma Concentrations ◽

Target Engagement ◽

Advisory Committees ◽

Refractory Acute Myeloid Leukemia ◽

Acute Myeloid ◽

Refractory Aml

Background: PLX2853 is an orally available, non-benzodiazepine BET (bromodomain and extraterminal domain) inhibitor that exhibits low nanomolar potency and a modest preference for binding to the second bromodomain (BD2) of the BET proteins. By regulating genes (e.g. MYC and BCL2) critical to leukemic cell growth and survival, PLX2853 demonstrated broad anti-leukemic activity both as a single agent and in combination with other therapeutic agents in preclinical models. The pharmacokinetic (PK) profile in solid tumor patients revealed a short half-life (< 3 hour) enabling high peak plasma concentrations and nearly complete elimination from the plasma 9 hour post dose. Since strong and prolonged suppression of BET proteins have often untoward effects in normal tissues, the PLX2853 PK profile is hypothesized to be associated with improved tolerability by allowing transient target engagement followed by time for recovery after daily dosing. Methods: We are conducting an open-label, Phase 1b (Ph1b) study of PLX2853 as a single oral agent administered daily in adult patients with relapsed or refractory acute myeloid leukemia (AML) or high risk myelodysplastic syndrome (MDS) using a modified continuous reassessment model (mCRM) with escalation with overdose control (EWOC) to determine the recommended phase 2 dose (RP2D). Up to 36 patients are expected to enroll. The dosing cycle and dose limiting toxicity window (DLT) is 21 days. Primary objectives include safety and PK. Secondary objectives include measures of preliminary efficacy, and exploratory objectives include pharmacodynamics (PD) biomarker assessments in various tissues. Enrollment through Cohort 2 (40 mg QD) is ongoing as of July 2019. Results: Five subjects with relapsed or refractory AML (median age 65 years) have received PLX2853 in escalating doses from 20 to 40 mg QD. Among these first 5 patients treated, the most common treatment emergent adverse events (AEs) regardless of causality in > 1 patient: decreased appetite (n=3), nausea (n=2), diarrhea (n=2), peripheral edema (n=2), cough (n=2), oropharyngeal pain (n=2), blood bilirubin increase (n=2), anemia (n=2), febrile neutropenia (n=2), fatigue (n=2), bacteremia (n=2), headache (n=2), dyspnea (n=2), and hypertension (n=2). Most were grade (G) 1-2. Treatment emergent AEs > G2 in > 1 patient included: anemia (n=2), febrile neutropenia (n=2) and hypertension (n=2). No treatment-related serious AEs or DLTs have been observed. Following a 20 mg daily dose of PLX2853, median time to reach maximal plasma concentrations (Tmax) is 1 hour and the absorption half-life (T1/2) is < 3 hours. Conclusions: In an ongoing Ph1b study, PLX2853 has now completed its first dosing cohort for patients with relapsed or refractory AML or high risk MDS, and no DLT has been observed yet. As dose escalation continues, PK, PD, preliminary safety and efficacy data will be assessed further to determine the clinical significance of target engagement. This clinical trial is registered at clinicaltrials.gov: NCT03787498. Disclosures Pemmaraju: mustangbio: Consultancy, Research Funding; abbvie: Consultancy, Honoraria, Research Funding; samus: Research Funding; celgene: Consultancy, Honoraria; cellectis: Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; novartis: Consultancy, Research Funding; plexxikon: Research Funding; Daiichi-Sankyo: Research Funding; sagerstrong: Research Funding; affymetrix: Research Funding; incyte: Consultancy, Research Funding. Borate:Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Solh:ADC Therapeutics: Research Funding; Amgen: Speakers Bureau; Celgene: Speakers Bureau. Borthakur:Polaris: Research Funding; Arvinas: Research Funding; Agensys: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Cantargia AB: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncoceutics, Inc.: Research Funding; Eli Lilly and Co.: Research Funding; BMS: Research Funding; AstraZeneca: Research Funding; Bayer Healthcare AG: Research Funding; Novartis: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Strategia Therapeutics: Research Funding; Cyclacel: Research Funding; Xbiotech USA: Research Funding; Eisai: Research Funding; Merck: Research Funding; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Oncoceutics: Research Funding; NKarta: Consultancy; Incyte: Research Funding; Janssen: Research Funding; GSK: Research Funding; PTC Therapeutics: Consultancy. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Zhang:Plexxikon Inc.: Employment. Powell:Plexxikon Inc.: Employment. Severson:Plexxikon Inc.: Employment. Inokuchi:Plexxikon Inc.: Employment. Matusow:Plexxikon Inc.: Employment. Halladay:Plexxikon Inc.: Employment. Hsu:Daiichi Sankyo, Inc.: Employment. Watkins:Plexxikon Inc.: Employment. Walling:Myovant Sciences: Consultancy; Nurix: Consultancy; Aduro Biotech: Consultancy; Plexxikon: Consultancy; CytomyX: Consultancy; Flag Therapeutics: Consultancy; Aminex: Consultancy; Immunext: Consultancy; SensenBio: Consultancy; Harpoon Therapeutics: Consultancy. Tsiatis:Plexxikon Inc.: Employment. Mims:PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

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Transcriptome Profiling of Pediatric Myeloproliferative Neoplasms Demonstrates Dysregulation of Platelet-Relevant Genes and Enrichment of Inflammatory and JAK2 Mediated Complement Pathways

Blood ◽

10.1182/blood-2019-125103 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4203-4203

Author(s):

Nicole Kucine ◽

Amanda R. Leonti ◽

Aishwarya Krishnan ◽

Rhonda E. Ries ◽

Ross L. Levine ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Platelet Activation ◽

Research Funding ◽

Mononuclear Cells ◽

Myeloproliferative Neoplasms ◽

Differentially Expressed ◽

Rna Seq ◽

Advisory Committees ◽

Normal Controls

Introduction : Myeloproliferative neoplasms (MPNs) are rare clonal bone marrow disorders in children characterized by high blood counts, predisposition to clotting events, and the potential to transform to myelofibrosis or acute myeloid leukemia (AML). Children with MPNs have lower rates of the known driver mutations (in JAK2, MPL, and CALR) than adult patients, and the underlying pathways and molecular derangements in young patients remain unknown. Given the lack of knowledge about pediatric MPNs, it is critical that we gain a better understanding of the dysregulated pathways in these diseases, which is necessary for improving disease understanding and broadening treatment options in children. Therefore, the objective of this work was to identify differentially expressed genes and pathways between children with MPNs and healthy controls, as well as children with AML, to guide further study. Methods : Mononuclear cells were extracted from peripheral blood of pediatric MPN patients (n=20) and pediatric and young adult AML patients (n=1410), and bone marrow of normal controls (NC, n=68). AML patient samples were being evaluated as part of a Children's Oncology Group planned analysis. To identify an expression profile unique to MPNs, transcriptome data from MPN patients was contrasted against NC and AML patients. All samples were ribodepleted and underwent Illumina RNA-Seq to generate transcriptome expression data. All analyses were performed in R. Differentially expressed genes were identified using the voom function from the limma package (v. 3.38.3), and enriched pathways were identified using the pathfindR package (v. 1.3.1). Unsupervised hierarchical clustering and heatmap generation was performed using the ComplexHeatmap package (v. 1.20.0). Results : MPN patient samples showed a unique expression signature, distinct from both AML patients and normal controls. Unsupervised PCA plot (Figure 1A) and heatmaps (Figure 1B) show that MPN samples cluster together. There were 4,012 differentially expressed (DE) genes in MPNs compared to NC and 6,743 DE genes in MPNs compared to AML patients. There were 2,493 shared genes between the 2 groups (Figure 1C.) Significantly DE genes between MPNs and other groups included multiple platelet-relevant genes including PF4 (CXCL4), PF4V1, P2RY12, and PPBP (CXCL7). Interestingly, PF4V1 was the most DE gene in MPNs compared to AML, and third highest versus NC. Dysregulation of some of these genes has been seen in adult MPNs, as well as thrombosis. Further comparison of transcriptome profiles between children with (n=13) and without (n=7)JAK2 mutations showed upregulation of three genes, CFB, C2, and SERPING1, which are all known complement genes, implicating complement activation in JAK2-mutated MPN patients. Complement activation has previously been reported in adult MPNs. Pathway enrichment analysis shows a number of immune and inflammatory pathways as enriched in MPN patients compared to both AML and NC. There were 179 enriched pathways in MPNs compared to AML and 142 compared to NC, with 134 common pathways (Figure 1D.) The systemic lupus erythematosus pathway was the most heavily enriched pathway in MPNs compared to both AML and NC. Additional pathways with significant enrichment include hematopoietic cell lineage, cytokine-cytokine interactions, DNA replication, and various infection-relevant pathways. The JAK-STAT signaling pathway was also enriched in MPNs compared to both AML and NC, as was the platelet activation pathway. Conclusion: Transcriptome evaluation of childhood MPNs shows enrichment of numerous inflammatory and immune pathways, highlighting that, as in adult MPNs, inflammation is implicated in pediatric MPNs. Furthermore, specific complement genes were upregulated in JAK2-mutant MPN. Upregulation of platelet-specific genes implies potential insights into disease mechanisms and warrants more study. Variations in the cell populations may account for some of the differences seen, however all samples were largely mononuclear cells, making their comparisons reasonable. Further analysis of this early data is needed to better assess inflammatory changes and platelet activation in pediatric MPNs, as are larger sample sizes. Individual cells may have differential expression of various genes, and future experiments with single-cell RNA-seq would be helpful to further elucidate differences. Disclosures Levine: Novartis: Consultancy; Loxo: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding; Gilead: Consultancy; Roche: Consultancy, Research Funding; Lilly: Honoraria; Amgen: Honoraria; Qiagen: Membership on an entity's Board of Directors or advisory committees; Imago Biosciences: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Prelude Therapeutics: Research Funding; Isoplexis: Membership on an entity's Board of Directors or advisory committees.

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Ultra-Sensitive Detection of Circulating Serum microRNAs (miRNAs) in Diffuse Large B-Cell Lymphoma (DLBCL) Patient-Derived Xenograft (PDX) Models and Correlation with Disease Status in DLBCL Patient

Blood ◽

10.1182/blood-2018-99-116789 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2973-2973

Author(s):

Afshin Beheshti ◽

Kristen E. Stevenson ◽

Ravi Dashnamoorthy ◽

Charles Vanderburg ◽

David M Weinstock ◽

...

Keyword(s):

Cell Line ◽

Board Of Directors ◽

Research Funding ◽

Healthy Controls ◽

Mirna Signature ◽

Advisory Committees ◽

Dlbcl Patient ◽

Wilcoxon Rank Sum Test ◽

Circulating Levels ◽

Pdx Models

Abstract Background: MiRNAs are small non-coding RNAs that regulate post-transcriptional gene expression, contribute to various facets of cancer pathogenesis, and may serve as a sensitive diagnostic platform as well as potential novel therapeutic targets. We recently identified a 9 miRNA (miR-15a, let-7c, let-7b, miR-27a, miR10b, miR-18a, miR130a, miR24, and miR155) signature in serum of Smurf2T/T mice that was detectable many months prior to the formation of visible DLBCL (Beheshti A et al PLOS One, 2017). We hypothesized that this circulating miRNA signature would also correlate with DLBCL status in PDX models and ultimately patients (pts). Methods: We performed droplet digital PCR (ddPCR), which allows for rapid quantification of single miRNA molecules. First, we examined the 9 aforementioned miRNAs in serum collected from mice xenografted with 5 DLBCL PDXs (Townsend et al. Cancer Cell 2016) and age-matched NSG mice without xenografts as controls. We also quantified the amount of miRNAs directly from all PDX cell lines utilized and 2 commercially available DLBCL cell lines for comparison. Next, we collected and analyzed serum from 86 pts with DLBCL in the following conditions: pre-treatment with first-line therapy (n=11); progression after treatment (n=7); during treatment (n=16); and in complete remission (n=52). Seventeen healthy non-tumor bearing individuals were used as controls. Median age of healthy controls was 52 years (range, 29-70) vs 64 years (range, 21-87) for DLBCL pts (p<0.001; Wilcoxon rank-sum test). 69% of DLBCL pts were male vs 35% of healthy controls (p=0.012; Fisher exact test). Results: The miRNA signature was enriched in DLBCL PDX mice with high expression confirmed in the 9 miRNAs, including MYC single and double hit models. The overall mean amounts of the miRNAs present in the serum of PDX bearing mice were mostly equivalent to the amount present in the original PDX cell line (Fig 1), with exception of one PDX cell line (DFBL-75549) that consistently had 100x more miRNA present in the serum of the mice vs associated cell line. In addition, we identified significantly increased circulating levels of the same miRNA signature in the serum of DLBCL pts (Table 1) (two-sided Wilcoxon rank-sum test, p<0.05) with similar patterns of change as seen in the murine models. Interestingly, higher circulating levels of let-7b were associated with a higher stage at diagnosis (stage I-II vs III-IV, median 54.0 vs. 163.2; P=0.007) and higher levels of both miR-27a and miR-24 were associated with having a MYC rearrangement (median 20.0 vs. 4.8; P=0.003; median 58.4 vs. 24.4; P=0.046). Higher levels of miR-18a were associated with Myc positivity by immunohistochemistry (0-9% of cells vs. 10-59% vs. ≥60%, median 3.3 vs. 2.8 vs. 8.8; P=0.030) as well as having received a prior therapy for DLBCL (median 4.8 for previously treated vs. 1.1 for untreated; P=0.016). Using the 23 on-treatment and progression samples compared with healthy samples, we selected cut-points based on the Youden Index from receiver operating curve (ROC) analysis and were able to classify the remission samples with an accuracy of 46%-88%. miR-24 performed the best in classification with a sensitivity of 85% and a specificity of 100%, while 6 of the 9 miRs had a classification rate >80%. Using a 5 miR signature with cut-points selected from recursive partitioning, we were able to classify remission samples with an accuracy of 91% (sensitivity 90%, specificity 94%). Conclusions: Altogether, ultrasensitive detection of circulating miRNAs originally identified in a lymphoma xenograft knockout model was readily detectable and highly elevated in DLBCL PDX models. Additionally, there were significantly increased circulating levels of the miRNA signature from the serum of DLBCL pts. Particular miRs were associated with pt stage and the presence of MYC overexpression or rearrangement in pts with DLBCL. Furthermore, circulating miRNAs were able to reliably distinguish DLBCL pts in remission from healthy controls based on a novel 5 miR signature. Validation in additional cohorts is needed to confirm whether miRNA quantification from serum may be a broadly applicable strategy for diagnosis, classification and response assessment among pts with DLBCL. Disclosures Weinstock: Astra Zeneca, JAX, Samumed, Regeneron, Sun Pharma, Prescient: Patents & Royalties; Genentech/Roche, Monsanto: Consultancy; Novartis: Consultancy, Research Funding; Novartis, Astra Zeneca, Abbvie, Aileron, Surface Oncology, Daiichi Sankyo: Research Funding; Novartis, Dragonfly, Travera, DxTerity, Travera: Consultancy; Travera: Equity Ownership. Evens:Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Affimed: Consultancy; Abbvie: Consultancy; Tesaro: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Novartis: Consultancy; Acerta: Consultancy.

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