Publications by authors named "Parvathi Ranganathan"

27 Publications

  • Page 1 of 1

Inhibition of Bromodomain and Extra Terminal (BET) Domain Activity Modulates the IL-23R/IL-17 Axis and Suppresses Acute Graft--Host Disease.

Front Oncol 2021 15;11:760789. Epub 2021 Oct 15.

Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States.

Acute graft--host disease (GVHD) is the leading cause of non-relapse mortality following allogeneic hematopoietic cell transplantation. The majority of patients non-responsive to front line treatment with steroids have an estimated overall 2-year survival rate of only 10%. Bromodomain and extra-terminal domain (BET) proteins influence inflammatory gene transcription, and therefore represent a potential target to mitigate inflammation central to acute GVHD pathogenesis. Using potent and selective BET inhibitors Plexxikon-51107 and -2853 (PLX51107 and PLX2853), we show that BET inhibition significantly improves survival and reduces disease progression in murine models of acute GVHD without sacrificing the beneficial graft--leukemia response. BET inhibition reduces T cell alloreactive proliferation, decreases inflammatory cytokine production, and impairs dendritic cell maturation both and . RNA sequencing studies in human T cells revealed that BET inhibition impacts inflammatory IL-17 and IL-12 gene expression signatures, and Chromatin Immunoprecipitation (ChIP)-sequencing revealed that BRD4 binds directly to the IL-23R gene locus. BET inhibition results in decreased IL-23R expression and function as demonstrated by decreased phosphorylation of STAT3 in response to IL-23 stimulation in human T cells as well as in mouse donor T cells . Furthermore, PLX2853 significantly reduced IL-23R+ and pathogenic CD4+ IFNγ+ IL-17+ double positive T cell infiltration in gastrointestinal tissues in an acute GVHD murine model. Our findings identify a role for BET proteins in regulating the IL-23R/STAT3/IL-17 pathway. Based on our preclinical data presented here, PLX51107 will enter clinical trial for refractory acute GVHD in a Phase 1 safety, biological efficacy trial.
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http://dx.doi.org/10.3389/fonc.2021.760789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8554203PMC
October 2021

Modulating endothelial cells with EGFL7 to diminish aGVHD after allogeneic bone marrow transplantation in mice.

Blood Adv 2021 Oct 15. Epub 2021 Oct 15.

Hopital Maisonneuve-Rosemont, Canada.

Acute graft versus host (aGVHD) is the second cause of death after allogeneic-hematopoietic stem cell transplant (allo-HSCT) underscoring the need for novel therapies. Based on previous work that endothelial cell dysfunction is present in aGVHD and that epidermal growth factor-like domain 7 (EGFL7) plays a significant role in decreasing inflammation by repressing endothelial cell activation and T cell migration, we hypothesized that increasing EGFL7 levels after allo-HSCT will diminish the severity of aGVHD. Here, we show that treatment with recombinant EGFL7 (rEGFL7) in two different murine models of aGVHD decreases aGVHD severity and improves survival in recipient mice after allogeneic transplantation with respect to controls without affecting graft versus leukemia effect. Furthermore, we showed that rEGFL7 treatment results in higher thymocytes, T, B and dendritic cells in recipient mice after allo-HSCT. This study constitutes a proof of concept of the ability of rEGFL7 therapy to reduce GHVD severity and mortality after allo-HSCT.
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http://dx.doi.org/10.1182/bloodadvances.2021005498DOI Listing
October 2021

Targeting Wnt signaling in acute myeloid leukemia stem cells.

Haematologica 2021 Sep 16. Epub 2021 Sep 16.

The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA; Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH.

Not available.
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http://dx.doi.org/10.3324/haematol.2020.266155DOI Listing
September 2021

PRMT5 regulates T cell interferon response and is a target for acute graft-versus-host disease.

JCI Insight 2020 04 23;5(8). Epub 2020 Apr 23.

Division of Hematology, Department of Internal Medicine, Comprehensive Cancer Center.

Acute graft-versus-host disease (aGVHD) is a T cell-mediated immunological disorder and the leading cause of nonrelapse mortality in patients who receive allogeneic hematopoietic cell transplants. Based on recent observations that protein arginine methyltransferase 5 (PRMT5) and arginine methylation are upregulated in activated memory T cells, we hypothesized that PRMT5 is involved in the pathogenesis of aGVHD. Here, we show that PRMT5 expression and enzymatic activity were upregulated in activated T cells in vitro and in T cells from mice developing aGVHD after allogeneic transplant. PRMT5 expression was also upregulated in T cells of patients who developed aGVHD after allogeneic hematopoietic cell transplant compared with those who did not develop aGVHD. PRMT5 inhibition using a selective small-molecule inhibitor (C220) substantially reduced mouse and human allogeneic T cell proliferation and inflammatory IFN-γ and IL-17 cytokine production. Administration of PRMT5 small-molecule inhibitors substantially improves survival, reducing disease incidence and clinical severity in mouse models of aGVHD without adversely affecting engraftment. Importantly, we show that PRMT5 inhibition retained the beneficial graft-versus-leukemia effect by maintaining cytotoxic CD8+ T cell responses. Mechanistically, we show that PRMT5 inhibition potently reduced STAT1 phosphorylation as well as transcription of proinflammatory genes, including interferon-stimulated genes and IL-17. Additionally, PRMT5 inhibition deregulates the cell cycle in activated T cells and disrupts signaling by affecting ERK1/2 phosphorylation. Thus, we have identified PRMT5 as a regulator of T cell responses and as a therapeutic target in aGVHD.
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http://dx.doi.org/10.1172/jci.insight.131099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205431PMC
April 2020

EGFL7 Antagonizes NOTCH Signaling and Represents a Novel Therapeutic Target in Acute Myeloid Leukemia.

Clin Cancer Res 2020 02 31;26(3):669-678. Epub 2019 Oct 31.

The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.

Purpose: EGF-like domain 7 (EGFL7) is a secreted protein and recently has been shown to play an important role in acute myeloid leukemia (AML); however, the underlying mechanism by which EGFL7 promotes leukemogenesis is largely unknown.

Experimental Design: Using an antibody interaction array, we measured the ability of EGFL7 to bind directly approximately 400 proteins expressed by primary AML blasts. Primary patient samples were stimulated with recombinant EGFL7 (rEGFL7) or anti-EGFL7 blocking antibody to assess alterations in downstream signaling and the ability to effect blast differentiation and survival. We treated three independent AML models with anti-EGFL7 or IgG1 control to determine whether anti-EGFL7 could prolong survival .

Results: We found EGFL7 significantly binds several signaling proteins important for normal and malignant hematopoiesis including NOTCH. Stimulation of AML blasts with rEGFL7 reduced NOTCH intracellular domain and NOTCH target gene expression while treatment with an anti-EGFL7 blocking antibody resulted in reactivation of NOTCH signaling, increased differentiation, and apoptosis. Competitive ligand-binding assays showed rEGFL7 inhibits DELTA-like (DLL) 4-mediated NOTCH activation while anti-EGFL7 combined with DLL4 significantly increased NOTCH activation and induced apoptosis. Using three different AML mouse models, we demonstrated that treatment with anti-EGFL7 alone results in increased survival.

Conclusions: Our data demonstrate that EGFL7 contributes to NOTCH silencing in AML by antagonizing canonical NOTCH ligand binding. Reactivation of NOTCH signaling using anti-EGFL7 results in prolonged survival of leukemic mice, supporting the use of EGFL7 as a novel therapeutic target in AML.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-2479DOI Listing
February 2020

Selinexor in combination with decitabine in patients with acute myeloid leukemia: results from a phase 1 study.

Leuk Lymphoma 2020 02 23;61(2):387-396. Epub 2019 Sep 23.

Division of Hematology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA.

Current treatment options for older and relapsed or refractory (R/R) acute myeloid leukemia (AML) patients are limited and represent an unmet need. Based on preclinical studies showing strong anti-leukemic effects this phase I dose-escalation study assessed the safety and preliminary clinical activity of the oral exportin-1 inhibitor, selinexor, in combination with the hypomethylating agent, decitabine 20 mg/m, in adults with R/R AML and in older (age ≥ 60) untreated AML patients. There were no protocol-defined dose limiting toxicities. The recommended phase 2 dose of selinexor was 60 mg (∼35 mg/m) given twice-weekly. Notable grade ≥3 toxicities included asymptomatic hyponatremia (68%), febrile neutropenia (44%), sepsis (44%), hypophosphatemia (36%), and pneumonia (28%). In 25 patients, the overall response rate was 40%. Modification of selinexor to a flat dose of 60 mg, twice-weekly for two weeks after decitabine, improved tolerability of the regimen and demonstrated preliminary clinical activity in poor-risk patients with AML.
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http://dx.doi.org/10.1080/10428194.2019.1665664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552944PMC
February 2020

Correction to: Determinant roles of dendritic cell-expressed Notch Delta-like and Jagged ligands on anti-tumor T-cell immunity.

J Immunother Cancer 2019 May 7;7(1):124. Epub 2019 May 7.

Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Wexner Medical Center and The James Comprehensive Cancer Center, 460 W 12th Ave, 484 BRT, Columbus, OH, 43210, USA.

Following publication of the original article [1], the author reported the wrong version of Figs. 5 and 7 have been published. The correct version of the figures can be found below.
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http://dx.doi.org/10.1186/s40425-019-0592-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6505242PMC
May 2019

Determinant roles of dendritic cell-expressed Notch Delta-like and Jagged ligands on anti-tumor T cell immunity.

J Immunother Cancer 2019 04 2;7(1):95. Epub 2019 Apr 2.

Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Wexner Medical Center and The James Comprehensive Cancer Center, 460 W 12th Ave, 484 BRT, Columbus, OH, 43210, USA.

Background: Notch intercellular communication instructs tissue-specific T-cell development and function. In this study, we explored the roles of dendritic cell (DC)-expressed Notch ligands in the regulation of T-cell effector function.

Methods: We generated mice with CD11c lineage-specific deletion of Notch Delta-like ligand (Dll)1 and Jagged (Jag)2. Using these genetically-ablated mice and engineered pharmacological Notch ligand constructs, the roles of various Delta-like and Jagged ligands in the regulation of T-cell-mediated immunity were investigated. We assessed tumor growth, mouse survival, cytokine production, immunophenotyping of myeloid and lymphoid populations infiltrating the tumors, expression of checkpoint molecules and T-cell function in the experimental settings of murine lung and pancreatic tumors and cardiac allograft rejection. Correlative studies were also performed for the expression of NOTCH ligands, NOTCH receptors and PD-1 on various subsets of myeloid and lymphoid cells in tumor-infiltrating immune cells analyzed from primary human lung cancers.

Results: Mice with CD11c lineage-specific deletion of Notch ligand gene Dll1, but not Jag2, exhibited accelerated growth of lung and pancreatic tumors concomitant with decreased antigen-specific CD8T-cell functions and effector-memory (Tem) differentiation. Increased IL-4 but decreased IFN-γ production and elevated populations of T-regulatory and myeloid-derived suppressor cells were observed in Dll1-ablated mice. Multivalent clustered DLL1-triggered Notch signaling overcame DC Dll1 deficiency and improved anti-tumor T-cell responses, whereas the pharmacological interference by monomeric soluble DLL1 construct suppressed the rejection of mouse tumors and cardiac allograft. Moreover, monomeric soluble JAG1 treatment reduced T-regulatory cells and improved anti-tumor immune responses by decreasing the expression of PD-1 on CD8Tem cells. A significant correlation was observed between DC-expressed Jagged and Delta-like ligands with Tem-expressed PD-1 and Notch receptors, respectively, in human lung tumor-infiltrates.

Conclusion: Our data show the importance of specific expression of Notch ligands on DCs in the regulation of T-cell effector function. Thus, strategies incorporating selectively engineered Notch ligands could provide a novel approach of therapeutics for modulating immunity in various immunosuppressive conditions including cancer.
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http://dx.doi.org/10.1186/s40425-019-0566-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6446314PMC
April 2019

Serum MicroRNA-155 in Acute Graft-Versus-Host-Disease (aGVHD).

Int J Bone Marrow Res 2019 16;2:079-82. Epub 2019 Aug 16.

Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA.

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http://dx.doi.org/10.29328/journal.ijbmr.1001007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168723PMC
August 2019

Knockout of both miR-15/16 loci induces acute myeloid leukemia.

Proc Natl Acad Sci U S A 2018 12 26;115(51):13069-13074. Epub 2018 Nov 26.

Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210;

MicroRNAs (miRNAs) have been extensively reported to be associated with hematological malignancies. The loss of miR-15a/16-1 at chromosome 13q14 is a hallmark of most of human chronic lymphocytic leukemia (CLL). Deletion of murine miR-15a/16-1 and miR-15b/16-2 has been demonstrated to promote B cell malignancies. Here, we evaluate the biological role of miR-15/16 clusters, crossbreeding miR-15a/16-1 and miR-15b/16-2 knockout mice. Unexpectedly, the complete deletion of both clusters promoted myeloproliferative disorders in the majority of the mice by the age of 5 months with a penetrance of 70%. These mice showed a significant enlargement of spleen and abnormal swelling of lymph nodes. Flow cytometry characterization demonstrated an expanded CD11b/Gr-1 double-positive myeloid population both in spleen and in bone marrow. The transplantation of splenocytes harvested from double-KO mice into wild-type recipient mice resulted in the development of myeloproliferative disorders, as observed in the donors. In vivo, miR-15/16 cluster deletion up-regulated the expression of Cyclin D1, Cyclin D2, and Bcl-2. Taken together, our findings identify a driver oncogenic role for miR-15/16 cluster deletion in different leukocytic cell lineages.
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http://dx.doi.org/10.1073/pnas.1814980115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6304943PMC
December 2018

Toll-Like Receptor Stimulation by MicroRNAs in Acute Graft-vs.-Host Disease.

Front Immunol 2018 5;9:2561. Epub 2018 Nov 5.

Division of Hematology, Department of Internal Medicine, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States.

Acute graft-vs.-host disease (aGVHD) is a frequent complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT), accounting for substantial morbidity and mortality associated with this treatment modality. The pathogenesis of aGVHD involves a complex cascade of humoral and cellular interactions in which donor T cells target HLA mismatched host tissues, causing tissue injury through secretion of pro-inflammatory cytokines and induction of direct cytotoxicity. Toll-like receptors (TLRs) are key components of the innate immune system that recognize endogenous danger-associated molecular patterns (DAMPs) and exogenous pathogen-associated molecular patterns (PAMPs). Patients receiving conditioning chemotherapy and/or whole-body irradiation prior to all-HSCT are prone to gastrointestinal damage and translocation of microbiota across compromised intestinal epithelium, resulting in release of PAMPs and DAMPs. These "danger signals" play critical roles in disease pathogenesis by both initiating and propagating aGVHD through dendritic cell maturation and alloreactive T cell responses. There are 10-15 TLRs identified in mammalian species, a subset of which recognize single-stranded RNA (ssRNA) and serve as a key component of viral immunity. Recently, ssRNAs other than those of viral origin have been investigated as potential ligands of TLRs. MicroRNAs (miRs) are short (19-24 nt) non-coding RNAs that play critical roles in a variety of diseases. While traditionally miRs post-translationally modulate gene expression, non-canonical functions such as regulating TLR stimulation by acting as TLR ligands have been described. Here, we review the role of TLRs in aGVHD pathogenesis, the function of miRs in TLR stimulation, and the recent literature describing miRs as TLR ligands in aGVHD.
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http://dx.doi.org/10.3389/fimmu.2018.02561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6230675PMC
September 2019

Complement-mediated thrombotic microangiopathy as a link between endothelial damage and steroid-refractory GVHD.

Blood Adv 2018 10;2(20):2619-2628

Division of Hematology, Department of Internal Medicine.

Transplant-associated thrombotic microangiopathy (TA-TMA), a complication of hematopoietic cell transplant (HCT), is associated with significant morbidity and mortality. The pathophysiology and overlap of TA-TMA with other posttransplant complications such as graft-versus-host disease (GVHD) is poorly understood. We retrospectively identified cases of TA-TMA among patients with grade 3/4 gastrointestinal (GI) GVHD, reviewed intestinal biopsy specimens, and performed correlative testing of biomarkers associated with TA-TMA. TA-TMA was more common in patients with steroid-refractory GVHD compared with steroid-responsive GVHD (79.3% vs 42.1%; = .001). Among patients surviving 100 days post-HCT, 1-year survival from day 100 was significantly better for patients who had not developed TA-TMA in the first 100 days (69.5% vs 36.7%; < .001). Only 1 of 7 proposed TA-TMA histology criteria (mucosal hemorrhage) differed significantly based on GVHD steroid response. In multivariable modeling, steroid-refractory GVHD was a risk factor for development of TA-TMA (hazard ratio, 3.09; 95% confidence interval, 1.68-5.67; < .001). There were no differences in complement activation at GVHD onset; however, 2 to 6 weeks later, patients with TA-TMA had higher levels of BBPlus and C5b-9, markers of alternative and terminal pathway activation (BBPlus: median, 600 vs 209.3 ng/mL; = .0045) (C5b-9: median, 425.9 vs 258.4 ng/mL; = .029). TA-TMA is associated with poor overall survival (OS) following HCT and may be detected early by histologic findings and may be differentiated from GVHD by measurement of alternative and terminal complement pathway activation. It is unknown whether treatment of TA-TMA will improve survival in steroid-refractory GVHD.
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http://dx.doi.org/10.1182/bloodadvances.2018020321DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6199668PMC
October 2018

MicroRNA-155 Modulates Acute Graft-versus-Host Disease by Impacting T Cell Expansion, Migration, and Effector Function.

J Immunol 2018 06 2;200(12):4170-4179. Epub 2018 May 2.

Division of Hematology, Department of Internal Medicine, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210;

MicroRNA-155 (miR-155) is a small noncoding RNA critical for the regulation of inflammation as well as innate and adaptive immune responses. MiR-155 has been shown to be dysregulated in both donor and recipient immune cells during acute graft-versus-host disease (aGVHD). We previously reported that miR-155 is upregulated in donor T cells of mice and humans with aGVHD and that mice receiving miR-155-deficient (miR155) splenocytes had markedly reduced aGVHD. However, molecular mechanisms by which miR-155 modulates T cell function in aGVHD have not been fully investigated. We identify that miR-155 expression in both donor CD8 T cells and conventional CD4 CD25 T cells is pivotal for aGVHD pathogenesis. Using murine aGVHD transplant experiments, we show that miR-155 strongly impacts alloreactive T cell expansion through multiple distinct mechanisms, modulating proliferation in CD8 donor T cells and promoting exhaustion in donor CD4 T cells in both the spleen and colon. Additionally, miR-155 drives a proinflammatory Th1 phenotype in donor T cells in these two sites, and miR-155 donor T cells are polarized toward an IL-4-producing Th2 phenotype. We further demonstrate that miR-155 expression in donor T cells regulates CCR5 and CXCR4 chemokine-dependent migration. Notably, we show that miR-155 expression is crucial for donor T cell infiltration into multiple target organs. These findings provide further understanding of the role of miR-155 in modulating aGVHD through T cell expansion, effector cytokine production, and migration.
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http://dx.doi.org/10.4049/jimmunol.1701465DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5988971PMC
June 2018

Discovery and functional implications of a miR-29b-1/miR-29a cluster polymorphism in acute myeloid leukemia.

Oncotarget 2018 Jan 12;9(4):4354-4365. Epub 2017 Dec 12.

Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA.

We previously reported that microRNA (miR)-29b is down-regulated and has a tumor suppressor role in acute myeloid leukemia (AML). However, little is known about the mechanisms responsible for miR-29b expression downregulation in AML. In this work we screened for mutations that could affect miR-29b expression. Using Sanger sequencing, we identified a germline thymidine (T) base deletion within the miR-29b-1/miR-29a cluster precursor in 16% of AML patients. Remarkably we found a significant enrichment for the presence of the miR-29 polymorphism in core binding factor (CBF) newly diagnosed AML patients ( = 61/303; 20%) with respect to age, sex and race matched controls ( = 43/402:11%, < 0.01). Mechanistically, this polymorphism affects the expression ratio of mature miR-29b and miR-29a by dampening the processing of miR-29a. RNA immunoprecipitation assays showed reduced DROSHA binding capacity to the polymorphism with respect to the controls. Finally, we showed that this polymorphism negatively impacts the ability of miR-29b-1/miR-29a cluster to target and , both known miR-29 targets.
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http://dx.doi.org/10.18632/oncotarget.23150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5796978PMC
January 2018

Pirfenidone: a breath of fresh air for cGVHD.

Blood 2017 05;129(18):2463-2464

THE OHIO STATE UNIVERSITY.

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http://dx.doi.org/10.1182/blood-2017-03-772103DOI Listing
May 2017

Serum miR-29a Is Upregulated in Acute Graft-versus-Host Disease and Activates Dendritic Cells through TLR Binding.

J Immunol 2017 03 3;198(6):2500-2512. Epub 2017 Feb 3.

Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210;

Acute graft-versus-host disease (aGVHD) continues to be a frequent and devastating complication of allogeneic hematopoietic stem cell transplantation (HSCT), posing as a significant barrier against the widespread use of HSCTs as a curative modality. Recent studies suggested serum/plasma microRNAs (miRs) may predict aGVHD onset. However, little is known about the functional role of circulating miRs in aGVHD. In this article, we show in two independent cohorts that miR-29a expression is significantly upregulated in the serum of allogeneic HSCT patients at aGVHD onset compared with non-aGVHD patients. Serum miR-29a is also elevated as early as 2 wk before time of diagnosis of aGVHD compared with time-matched control subjects. We demonstrate novel functional significance of serum miR-29a by showing that miR-29a binds and activates dendritic cells via TLR7 and TLR8, resulting in the activation of the NF-κB pathway and secretion of proinflammatory cytokines TNF-α and IL-6. Treatment with locked nucleic acid anti-miR-29a significantly improved survival in a mouse model of aGVHD while retaining graft-versus-leukemia effects, unveiling a novel therapeutic target in aGVHD treatment or prevention.
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http://dx.doi.org/10.4049/jimmunol.1601778DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5340605PMC
March 2017

miR-146b antagomir-treated human Tregs acquire increased GVHD inhibitory potency.

Blood 2016 09 2;128(10):1424-35. Epub 2016 Aug 2.

Division of Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Cancer Center, Minneapolis, MN;

CD4(+)CD25(+)FoxP3(+) thymic-derived regulatory T cells (tTregs) are indispensable for maintaining immune system equilibrium. Adoptive transfer of tTregs is an effective means of suppressing graft-versus-host disease (GVHD) in murine models and in early human clinical trials. Tumor necrosis factor receptor-associated factor 6 (TRAF6), an ubiquitin-conjugating enzyme that mediates nuclear factor κB (NF-κB) activation, plays an essential role in modulating regulatory T cell survival and function. MicroRNAs (miRNAs) are noncoding RNAs, which mediate RNA silencing and posttranscriptional gene repression. By performing comprehensive TaqMan Low Density Array miRNA assays, we identified 10 miRNAs differentially regulated in human tTreg compared with control T cells. One candidate, miR-146b, is preferentially and highly expressed in human naive tTregs compared with naive CD4 T cells. miRNA prediction software revealed that TRAF6 was the one of the top 10 scored mRNAs involved tTreg function with the highest probability as a potential miR-146b target. Antagomir-mediated knockdown of miRNA-146b, but not another miRNA-146 family member (miRNA-146a), enhanced TRAF6 expression. TRAF6, in turn, increases NF-κB activation, which is essential for tTreg function as well as Foxp3 protein and antiapoptotic gene expression, and downregulates proapoptotic gene expression. miR-146b knockdown increased the nuclear localization and expression of genes regulated by NF-κB, which was associated with enhanced tTreg survival, proliferation, and suppressive function measured in vitro and in vivo. TRAF6 inhibition had the opposite effects. We conclude that an miR-146b-TRAF6-NF-κB-FoxP3 signaling pathway restrains regulatory T cell survival, proliferation, and suppressor function. In vitro exposure of human tTregs to miR-146b antagomirs can be exploited to improve the clinical efficacy of human adoptive tTreg transfer in a GVHD setting.
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http://dx.doi.org/10.1182/blood-2016-05-714535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5016708PMC
September 2016

XPO1 Inhibition using Selinexor Synergizes with Chemotherapy in Acute Myeloid Leukemia by Targeting DNA Repair and Restoring Topoisomerase IIα to the Nucleus.

Clin Cancer Res 2016 Dec 29;22(24):6142-6152. Epub 2016 Jun 29.

The Ohio State University, Columbus, Ohio.

Purpose: Selinexor, a selective inhibitor of XPO1, is currently being tested as single agent in clinical trials in acute myeloid leukemia (AML). However, considering the molecular complexity of AML, it is unlikely that AML can be cured with monotherapy. Therefore, we asked whether adding already established effective drugs such as topoisomerase (Topo) II inhibitors to selinexor will enhance its anti-leukemic effects in AML.

Experimental Design: The efficacy of combinatorial drug treatment using Topo II inhibitors (idarubicin, daunorubicin, mitoxantrone, etoposide) and selinexor was evaluated in established cellular and animal models of AML.

Results: Concomitant treatment with selinexor and Topo II inhibitors resulted in therapeutic synergy in AML cell lines and patient samples. Using a xenograft MV4-11 AML mouse model, we show that treatment with selinexor and idarubicin significantly prolongs survival of leukemic mice compared with each single therapy.

Conclusions: Aberrant nuclear export and cytoplasmic localization of Topo IIα has been identified as one of the mechanisms leading to drug resistance in cancer. Here, we show that in a subset of patients with AML that express cytoplasmic Topo IIα, selinexor treatment results in nuclear retention of Topo IIα protein, resulting in increased sensitivity to idarubicin. Selinexor treatment of AML cells resulted in a c-MYC-dependent reduction of DNA damage repair genes (Rad51 and Chk1) mRNA and protein expression and subsequent inhibition of homologous recombination repair and increased sensitivity to Topo II inhibitors. The preclinical data reported here support further clinical studies using selinexor and Topo II inhibitors in combination to treat AML. Clin Cancer Res; 22(24); 6142-52. ©2016 AACR.
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http://dx.doi.org/10.1158/1078-0432.CCR-15-2885DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161584PMC
December 2016

Dissection of the Major Hematopoietic Quantitative Trait Locus in Chromosome 6q23.3 Identifies miR-3662 as a Player in Hematopoiesis and Acute Myeloid Leukemia.

Cancer Discov 2016 09 27;6(9):1036-51. Epub 2016 Jun 27.

The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.

Unlabelled: Chromosomal aberrations and multiple genome-wide association studies (GWAS) have established a major hematopoietic quantitative trait locus in chromosome 6q23.3. The locus comprises an active enhancer region, in which some of the associated SNPs alter transcription factor binding. We now identify miR-3662 as a new functional driver contributing to the associated phenotypes. The GWAS SNPs are strongly associated with higher miR-3662 expression. Genome editing of rs66650371, a three-base-pair deletion, suggests a functional link between the SNP genotype and the abundance of miR-3662. Increasing miR-3662's abundance increases colony formation in hematopoietic progenitor cells, particularly the erythroid lineage. In contrast, miR-3662 is not expressed in acute myeloid leukemia cells, and its overexpression has potent antileukemic effects in vitro and in vivo Mechanistically, miR-3662 directly targets NF-κB-mediated transcription. Thus, miR-3662 is a new player of the hematopoietic 6q23.3 locus.

Significance: The characterization of miR-3662 has identified a new actor in the prominent hematopoietic quantitative trait locus in chromosome 6q23.3. The mechanistic insights into miR-3662's function may reveal novel or only partially known pathways for normal and malignant hematopoietic cell proliferation. Cancer Discov; 6(9); 1036-51. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 932.
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http://dx.doi.org/10.1158/2159-8290.CD-16-0023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5168803PMC
September 2016

Programmed death ligand-1 expression on donor T cells drives graft-versus-host disease lethality.

J Clin Invest 2016 07 13;126(7):2642-60. Epub 2016 Jun 13.

Programmed death ligand-1 (PD-L1) interaction with PD-1 induces T cell exhaustion and is a therapeutic target to enhance immune responses against cancer and chronic infections. In murine bone marrow transplant models, PD-L1 expression on host target tissues reduces the incidence of graft-versus-host disease (GVHD). PD-L1 is also expressed on T cells; however, it is unclear whether PD-L1 on this population influences immune function. Here, we examined the effects of PD-L1 modulation of T cell function in GVHD. In patients with severe GVHD, PD-L1 expression was increased on donor T cells. Compared with mice that received WT T cells, GVHD was reduced in animals that received T cells from Pdl1-/- donors. PD-L1-deficient T cells had reduced expression of gut homing receptors, diminished production of inflammatory cytokines, and enhanced rates of apoptosis. Moreover, multiple bioenergetic pathways, including aerobic glycolysis, oxidative phosphorylation, and fatty acid metabolism, were also reduced in T cells lacking PD-L1. Finally, the reduction of acute GVHD lethality in mice that received Pdl1-/- donor cells did not affect graft-versus-leukemia responses. These data demonstrate that PD-L1 selectively enhances T cell-mediated immune responses, suggesting a context-dependent function of the PD-1/PD-L1 axis, and suggest selective inhibition of PD-L1 on donor T cells as a potential strategy to prevent or ameliorate GVHD.
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http://dx.doi.org/10.1172/JCI85796DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4922691PMC
July 2016

Atorvastatin for the Prophylaxis of Acute Graft-versus-Host Disease in Patients Undergoing HLA-Matched Related Donor Allogeneic Hematopoietic Stem Cell Transplantation (allo-HCT).

Biol Blood Marrow Transplant 2016 Jan 6;22(1):71-9. Epub 2015 Aug 6.

Division of Hematology, Department of Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.

Statins possess potent immunomodulatory effects that may play a role in preventing acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). We performed a phase II study of atorvastatin for aGVHD prophylaxis when given to allo-HCT recipients and their HLA-matched sibling donors. Atorvastatin (40 mg/day) was administered to sibling donors, beginning 14 days before the anticipated start of stem cell collection. Allo-HCT recipients (n = 40) received atorvastatin (40 mg/day) in addition to standard aGVHD prophylaxis. The primary endpoint was cumulative incidence of grades II to IV aGVHD at day 100. Atorvastatin was well tolerated, with no attributable grades III to IV toxicities in donors or their recipients. Day 100 and 180 cumulative incidences of grades II to IV aGVHD were 30% (95% confidence interval [CI], 17% to 45%) and 40% (95% CI, 25% to 55%), respectively. One-year cumulative incidence of chronic GVHD was 43% (95% CI, 32% to 69%). One-year nonrelapse mortality and relapse incidences were 5.5% (95% CI, .9% to 16.5%) and 38% (95% CI, 18% to 47%), respectively. One-year progression-free and overall survival rates were 54% (95% CI, 38% to 71%) and 82% (95% CI, 69% to 94%). One-year GVHD-free, relapse-free survival was 27% (95% CI, 16% to 47%). These results did not differ from our historical control subjects (n = 96). Although safe and tolerable, the addition of atorvastatin did not appear to provide any benefit to standard GVHD prophylaxis alone.
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http://dx.doi.org/10.1016/j.bbmt.2015.07.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4706501PMC
January 2016

Decitabine priming enhances the antileukemic effects of exportin 1 (XPO1) selective inhibitor selinexor in acute myeloid leukemia.

Blood 2015 Apr 25;125(17):2689-92. Epub 2015 Feb 25.

Division of Hematology, Department of Internal Medicine, The Comprehensive Cancer Center, and.

The prognosis of acute myeloid leukemia (AML) is poor, highlighting the need for novel treatments. Hypomethylating agents, including decitabine are used to treat elderly AML patients with relative success. Targeting nuclear export receptor (exportin 1 [XPO1]) is a novel approach to restore tumor suppressor (TS) function in AML. Here, we show that sequential treatment of AML blasts with decitabine followed by selinexor (XPO1 inhibitor) enhances the antileukemic effects of selinexor. These effects could be mediated by the re-expression of a subset of TSs (CDKN1A and FOXO3A) that are epigenetically silenced via DNA methylation, and cytoplasmic-nuclear trafficking is regulated by XPO1. We observed a significant upregulation of CDKN1A and FOXO3A in decitabine- versus control-treated cells. Sequential treatment of decitabine followed by selinexor in an MV4-11 xenograft model significantly improved survival compared with selinexor alone. On the basis of these preclinical results, a phase 1 clinical trial of decitabine followed by selinexor in elderly patients with AML has been initiated.
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http://dx.doi.org/10.1182/blood-2014-10-607648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408293PMC
April 2015

Implications of the miR-10 family in chemotherapy response of NPM1-mutated AML.

Blood 2014 Apr 4;123(15):2412-5. Epub 2014 Mar 4.

Division of Hematology.

Nucleophosmin-mutated acute myeloid leukemia (NPM1mut-AML) patients have a high rate of complete remission (CR) to induction chemotherapy. However, the mechanisms responsible for such effects are unknown. Because miR-10 family members are expressed at high levels in NPM1mut-AML, we evaluated whether these microRNAs could predict chemotherapy response in AML. We found that high baseline miR-10 family expression in 54 untreated cytogenetically heterogeneous AML patients was associated with achieving CR. However, when we included NPM1 mutation status in the multivariable model, there was a significant interaction effect between miR-10a-5p expression and NPM1 mutation status. Similar results were observed when using a second cohort of 183 cytogenetically normal older (age ≥ 60 years) AML patients. Loss- and gain-of-function experiments using miR-10a-5p in cell lines and primary blasts did not demonstrate any effect in apoptosis or cell proliferation at baseline or after chemotherapy. These data support a bystander role for the miR-10 family in NPM1mut-AML.
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http://dx.doi.org/10.1182/blood-2013-10-532374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983615PMC
April 2014

Preclinical activity of a novel CRM1 inhibitor in acute myeloid leukemia.

Blood 2012 Aug 7;120(9):1765-73. Epub 2012 Jun 7.

Division of Hematology, Department of Medicine, The Ohio State University, Columbus 43210, USA.

Chromosome maintenance protein 1 (CRM1) is a nuclear export receptor involved in the active transport of tumor suppressors (e.g., p53 and nucleophosmin) whose function is altered in cancer because of increased expression and overactive transport. Blocking CRM1-mediated nuclear export of such proteins is a novel therapeutic strategy to restore tumor suppressor function. Orally bioavailable selective inhibitors of nuclear export (SINE) that irreversibly bind to CRM1 and block the function of this protein have been recently developed. Here we investigated the antileukemic activity of KPT-SINE (KPT-185 and KPT-276) in vitro and in vivo in acute myeloid leukemia (AML). KPT-185 displayed potent antiproliferative properties at submicromolar concentrations (IC50 values; 100-500 nM), induced apoptosis (average 5-fold increase), cell-cycle arrest, and myeloid differentiation in AML cell lines and patient blasts. A strong down-regulation of the oncogene FLT3 after KPT treatment in both FLT3-ITD and wild-type cell lines was observed. Finally, using the FLT3-ITD-positive MV4-11 xenograft murine model, we show that treatment of mice with oral KPT-276 (analog of KPT-185 for in vivo studies) significantly prolongs survival of leukemic mice (P < .01). In summary, KPT-SINE are highly potent in vitro and in vivo in AML. The preclinical results reported here support clinical trials of KPT-SINE in AML.
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http://dx.doi.org/10.1182/blood-2012-04-423160DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433086PMC
August 2012

Regulation of acute graft-versus-host disease by microRNA-155.

Blood 2012 May 9;119(20):4786-97. Epub 2012 Mar 9.

Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, Ohio State University, 460 West 12th Ave., Columbus, OH 43210, USA.

Acute graft-versus-host disease (aGVHD) remains a major complication of allogeneic hematopoietic stem cell transplant (alloHSCT), underscoring the need to further elucidate its mechanisms and develop novel treatments. Based on recent observations that microRNA-155 (miR-155) is up-regulated during T-cell activation, we hypothesized that miR-155 is involved in the modulation of aGVHD. Here we show that miR-155 expression was up-regulated in T cells from mice developing aGVHD after alloHSCT. Mice receiving miR-155-deficient donor lymphocytes had markedly reduced lethal aGVHD, whereas lethal aGVHD developed rapidly in mice recipients of miR-155 overexpressing T cells. Blocking miR-155 expression using a synthetic anti-miR-155 after alloHSCT decreased aGVHD severity and prolonged survival in mice. Finally, miR-155 up-regulation was shown in specimens from patients with pathologic evidence of intestinal aGVHD. Altogether, our data indicate a role for miR-155 in the regulation of GVHD and point to miR-155 as a novel target for therapeutic intervention in this disease.
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http://dx.doi.org/10.1182/blood-2011-10-387522DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367879PMC
May 2012

Somatic hypermutation of TCR γ V genes in the sandbar shark.

Dev Comp Immunol 2012 May 8;37(1):176-83. Epub 2011 Sep 8.

Department of Immunobiology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA.

In a recent publication we demonstrated that somatic hypermutation occurs in the V region of the TCR γ gene of the sandbar shark (Carcharhinus plumbeus). We hypothesize that similar mechanisms are used to generate somatic mutations in both immunoglobulin and TCR γ genes of the sharks. Two distinct patterns of mutation occur, single nucleotide mutations (point mutations) and mutations comprising 2-5 consecutive bases (tandem mutations). Our data indicates that point mutations occur by a mechanism similar to that of somatic hypermutation in immunoglobulin genes of mammals, whereas tandem mutations may be generated by an error-prone DNA polymerase with terminal deoxynucleotidyl transferase (TdT)-like activity. Shark hotspot motifs identical to those of higher vertebrates were identified. We confirm that, as in immunoglobulin of sharks and higher vertebrates, highly significant targeting of AID activity to the classical DGYW/WRCH motif occurs in somatic hypermutation of sandbar shark TCR γ V genes. Our analysis suggests that the purpose of somatic mutations in shark TCR γ V-regions is to generate a more diverse repertoire in γ/δ receptors, rather than receptors with higher affinity.
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http://dx.doi.org/10.1016/j.dci.2011.08.018DOI Listing
May 2012

Autoantibodies to the delta-opioid receptor function as opioid agonists and display immunomodulatory activity.

J Neuroimmunol 2009 Dec 30;217(1-2):65-73. Epub 2009 Oct 30.

Department of Immunobiology, University of Arizona, 1656 E. Mabel Street, PO Box 245221, Tucson, Arizona 85724, USA.

In this report, we show that affinity purified human anti-delta opioid receptor (DOR) autoantibodies from IVIG are specific to DOR and possess agonistic properties displayed by their ability to dramatically decrease forskolin stimulated cAMP accumulation. Anti-DOR autoantibody also caused phosphorylation of the opioid receptor. Anti-DOR autoantibody treatment showed a significant reduction in CXCR4 gene expression as well as surface protein expression. In contrast, anti-DOR autoantibody treatment significantly upregulated CCR5 gene and protein expression. The presence of anti-DOR autoantibodies in IVIG and their potent immunomodulatory activity is further evidence to support the cross-talk between the neuroendocrine and immune systems.
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http://dx.doi.org/10.1016/j.jneuroim.2009.10.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861486PMC
December 2009
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