Disease-initiating mutations in the transcription factor RUNX1 occur as germline and somatic events that cause leukemias with particularly poor prognosis. However, the role of RUNX1 in leukemogenesis is not fully understood and effective therapies for RUNX1-mutant leukemias remain elusive. Here, we use primary patient samples and a RUNX1 knockout model in primary human hematopoietic cells to investigate how RUNX1 loss contributes to leukemic progression and to identify targetable vulnerabilities. Surprisingly, we found that RUNX1 loss decreased proliferative capacity and stem cell function. However, RUNX1-deficient cells selectively upregulated the interleukin-3 (IL-3) receptor. Exposure to IL-3, but not other JAK/STAT cytokines, rescued RUNX1 KO proliferative and competitive defects. Further, we demonstrated that RUNX1 loss repressed JAK/STAT signaling and rendered RUNX1-deficient cells sensitive to JAK inhibitors. Our study identifies a dependency of RUNX1-mutant leukemias on IL-3/JAK/STAT signaling, which may enable these aggressive blood cancers to be targeted with existing agents.
Amy C. Fan, Yusuke Nakauchi, Lawrence Bai, Armon Azizi, Kevin A. Nuno, Feifei Zhao, Thomas Köhnke, Daiki Karigane, David Cruz-Hernandez, Andreas Reinisch, Purvesh Khatri, Ravindra Majeti
Entry of antigen-specific T cells into human tumors is critical for immunotherapy, but the underlying mechanisms are poorly understood. Here, we combined high-dimensional spatial analyses with in vitro and in vivo modeling to study the mechanisms underlying immune infiltration in human multiple myeloma (MM) and its precursor monoclonal gammopathy of undetermined significance (MGUS). Clustered tumor growth was a feature of MM but not MGUS biopsies, and this growth pattern was reproduced in humanized mouse models. MM biopsies exhibited intralesional as well as spatial heterogeneity, with coexistence of T cell–rich and T cell–sparse regions and the presence of areas of T cell exclusion. In vitro studies demonstrated that T cell entry into MM clusters was regulated by agonistic signals and CD2-CD58 interactions. Upon adoptive transfer, antigen-specific T cells localized to the tumor site but required in situ DC–mediated antigen presentation for tumor entry. C-type lectin domain family 9 member A–positive (CLEC9A+) DCs appeared to mark portals of entry for gradients of T cell infiltration in MM biopsies, and their proximity to T cell factor 1–positive (TCF1+) T cells correlated with disease state and risk status. These data illustrate a role for tumor-associated DCs and in situ activation in promoting the infiltration of antigen-specific T cells in MM and provide insights into spatial alterations in tumor/immune cells with malignant evolution.
M. Hope Robinson, Nancy Y. Villa, David L. Jaye, Ajay K. Nooka, Alyssa Duffy, Samuel S. McCachren, Julia Manalo, Jeffrey M. Switchenko, Sierra Barnes, Sayalee Potdar, Maryam I. Azeem, Ava A. Horvat, Vaunita C. Parihar, Jingjing Gong, Yan Liang, Geoffrey H. Smith, Vikas A. Gupta, Lawrence H. Boise, Jonathan L. Kaufman, Craig C. Hofmeister, Nisha S. Joseph, Sagar Lonial, Kavita M. Dhodapkar, Madhav V. Dhodapkar
Clonal hematopoiesis plays a critical role in the initiation and development of hematologic malignancies. In patients with del(5q) myelodysplastic syndrome (MDS), the transcription factor FOXM1 is frequently downregulated in CD34+ cells. In this study, we demonstrated that Foxm1 haploinsufficiency disturbed normal hematopoiesis and conferred a competitive repopulation advantage for a short period. However, it impaired the long-term self-renewal capacity of hematopoietic stem cells, recapitulating the phenotypes of abnormal hematopoietic stem cells observed in patients with MDS. Moreover, heterozygous inactivation of Foxm1 led to an increase in DNA damage in hematopoietic stem/progenitor cells (HSPCs). Foxm1 haploinsufficiency induced hematopoietic dysplasia in a mouse model with LPS-induced chronic inflammation and accelerated AML-ETO9a–mediated leukemogenesis. We have also identified Parp1, an important enzyme that responds to various types of DNA damage, as a target of Foxm1. Foxm1 haploinsufficiency decreased the ability of HSPCs to efficiently repair DNA damage by downregulating Parp1 expression. Our findings suggest that the downregulation of the Foxm1-Parp1 molecular axis may promote clonal hematopoiesis and reduce genome stability, contributing to del(5q) MDS pathogenesis.
Chunjie Yu, Yue Sheng, Fang Yu, Hongyu Ni, Alan Qiu, Yong Huang, Zhijian Qian
STAT3 deficiency (STAT3–/–) in donor T cells prevents graft-versus-host disease (GVHD), but the impact on graft-versus-leukemia (GVL) activity and mechanisms of GVHD prevention remains unclear. Here, using murine models of GVHD, we show that STAT3–/– donor T cells induced only mild reversible acute GVHD while preserving GVL effects against nonsusceptible acute lymphoblastic leukemia (ALL) cells in a donor T cell dose–dependent manner. GVHD prevention depended on programmed death ligand 1/programmed cell death protein 1 (PD-L1/PD-1) signaling. In GVHD target tissues, STAT3 deficiency amplified PD-L1/PD-1 inhibition of glutathione (GSH)/Myc pathways that regulate metabolic reprogramming in activated T cells, with decreased glycolytic and mitochondrial ATP production and increased mitochondrial ROS production and dysfunction, leading to tissue-specific deletion of host-reactive T cells and prevention of GVHD. Mitochondrial STAT3 deficiency alone did not reduce GSH expression or prevent GVHD. In lymphoid tissues, the lack of host-tissue PD-L1 interaction with PD-1 reduced the inhibition of the GSH/Myc pathway despite reduced GSH production caused by STAT3 deficiency and allowed donor T cell functions that mediate GVL activity. Therefore, STAT3 deficiency in donor T cells augments PD-1 signaling–mediated inhibition of GSH/Myc pathways and augments dysfunction of T cells in GVHD target tissues while sparing T cells in lymphoid tissues, leading to prevention of GVHD while preserving GVL effects.
Qinjian Li, Xiaoqi Wang, Qingxiao Song, Shijie Yang, Xiwei Wu, Dongyun Yang, Isabelle J. Marié, Hanjun Qin, Moqian Zheng, Ubaydah Nasri, Xiaohui Kong, Bixin Wang, Elizabeth Lizhar, Kaniel Cassady, Josh Tompkins, David Levy, Paul J. Martin, Xi Zhang, Defu Zeng
Sickle cell disease (SCD) is a hereditary hemoglobinopathy characterized by painful vaso-occlusive crises (VOC) and chronic hemolysis. The mononuclear phagocyte system is pivotal to SCD pathophysiology, but the mechanisms governing monocyte/macrophage differentiation remain unknown. This study examined the influence of hemolysis on circulating monocyte trajectories in SCD. We discovered that hemolysis stimulated CSF-1 production, partly by endothelial cells via Nrf2, promoting classical monocyte (CMo) differentiation into blood patrolling monocytes (PMo) in SCD mice. However, hemolysis also upregulated CCL-2 through IFN-I, inducing CMo transmigration and differentiation into tissue monocyte-derived macrophages. Blocking CMo transmigration by anti-P-selectin antibody in SCD mice increased circulating PMo, corroborating that CMo-to-tissue macrophage differentiation occurs at the expense of CMo-to-blood PMo differentiation. We observed a positive correlation between plasma CSF-1/CCL-2 ratios and blood PMo levels in SCD patients, underscoring the clinical significance of these two opposing factors in monocyte differentiation. Combined treatment with CSF-1 and anti-P-selectin antibody more effectively increased PMo numbers and reduced stasis compared to single-agent therapies in SCD mice. Altogether, these data indicate that monocyte fates are regulated by the balance between two heme pathways, Nrf2-CSF-1 and IFN-I-CCL-2, and suggest that the CSF-1/CCL-2 ratio may present a diagnostic and therapeutic target in SCD.
Yunfeng Liu, Shan Su, Sarah Shayo, Weili Bao, Mouli Pal, Kai Dou, Patricia A. Shi, Banu Aygun, Sally Campbell-Lee, Cheryl A. Lobo, Avital Mendelson, Xiuli An, Deepa Manwani, Hui Zhong, Karina Yazdanbakhsh
Protease activated receptor (PAR) 4 (gene: F2RL3) harbors a functional dimorphism, rs773902 A/G (encoding Thr120/Ala120, respectively) and is associated with greater platelet aggregation. The A allele frequency is more common in Black individuals, and Black individuals have a higher incidence of ischemic stroke than White individuals. However, it is not recognized whether the A allele is responsible for worse stroke outcomes. To directly test the in vivo effect of this variant on stroke, we generated mice where F2rl3 was replaced by F2RL3, thereby expressing human PAR4 (hPAR4) with either Thr120 or Ala120. Compared to hPAR4 Ala120 mice, hPAR4 Thr120 mice had worse stroke outcomes, mediated in part by enhanced platelet activation and platelet-neutrophil interactions. Analyses of 7620 Black subjects with 487 incident ischemic strokes demonstrated the AA genotype was a risk for incident ischemic stroke and worse functional outcomes. In humanized mice, ticagrelor with or without aspirin improved stroke outcomes in hPAR4 Ala120 mice, but not in hPAR4 Thr120 mice. P-selectin blockade improved stroke outcomes and reduced platelet-neutrophil interactions in hPAR4 Thr120 mice. Our results may explain some of the racial disparity in stroke and support the need for studies of non-standard anti-platelet therapies for patients expressing PAR4 Thr120.
Frederik Denorme, Nicole D. Armstrong, Michelle L. Stoller, Irina Portier, Emilia A. Tugolukova, Rikki M. Tanner, Emilie Montenont, Seema Bhatlekar, Mark Cody, John L. Rustad, Abigail Ajanel, Neal D. Tolley, Darian C. Murray, Julie L. Boyle, Marvin T. Nieman, Steven E. McKenzie, Christian Con Yost, Leslie A. Lange, Mary Cushman, Marguerite R. Irvin, Paul F. Bray, Robert A. Campbell
RAS mutations are among the most prevalent oncogenic drivers in cancers. RAS proteins propagate signals only when associated with cellular membranes as a consequence of lipid modifications that impact their trafficking. Here, we discovered that RAB27B, a RAB family small GTPase, controlled NRAS palmitoylation and trafficking to the plasma membrane, a localization required for activation. Our proteomic studies revealed RAB27B upregulation in CBL- or JAK2-mutated myeloid malignancies, and its expression correlated with poor prognosis in acute myeloid leukemias (AMLs). RAB27B depletion inhibited the growth of CBL-deficient or NRAS-mutant cell lines. Strikingly, Rab27b deficiency in mice abrogated mutant but not WT NRAS–mediated progenitor cell growth, ERK signaling, and NRAS palmitoylation. Further, Rab27b deficiency significantly reduced myelomonocytic leukemia development in vivo. Mechanistically, RAB27B interacted with ZDHHC9, a palmitoyl acyltransferase that modifies NRAS. By regulating palmitoylation, RAB27B controlled c-RAF/MEK/ERK signaling and affected leukemia development. Importantly, RAB27B depletion in primary human AMLs inhibited oncogenic NRAS signaling and leukemic growth. We further revealed a significant correlation between RAB27B expression and sensitivity to MEK inhibitors in AMLs. Thus, our studies presented a link between RAB proteins and fundamental aspects of RAS posttranslational modification and trafficking, highlighting future therapeutic strategies for RAS-driven cancers.
Jian-Gang Ren, Bowen Xing, Kaosheng Lv, Rachel A. O’Keefe, Mengfang Wu, Ruoxing Wang, Kaylyn M. Bauer, Arevik Ghazaryan, George M. Burslem, Jing Zhang, Ryan M. O’Connell, Vinodh Pillai, Elizabeth O. Hexner, Mark R. Philips, Wei Tong
During emergency hematopoiesis, hematopoietic stem cells (HSCs) rapidly proliferate to produce myeloid and lymphoid effector cells, a response that is critical against infection or tissue injury. If unresolved, this process leads to sustained inflammation which can cause life-threatening diseases and cancer. We have identified a novel role of Dpf2 in inflammation. Dpf2 is a defining subunit of the hematopoietic-specific BAF (SWI/SNF) chromatin-remodeling complex, and it is mutated in multiple cancers and neurological disorders. We uncover that hematopoietic-specific Dpf2 knock-out mice develop leukopenia, severe anemia and lethal systemic inflammation characterized by histiocytic and fibrotic tissue infiltration, resembling a clinical hyper-inflammatory state. Dpf2 loss impairs the polarization of macrophages responsible for tissue repair, induces unrestrained activation of T helper cells, and generates an emergency-like state of HSC hyperproliferation and myeloid-biased differentiation. Mechanistically, Dpf2 deficiency results in the loss of the BAF catalytic subunit Brg1 from Nrf2-controlled enhancers, impairing the anti-oxidant and anti-inflammatory transcriptional response needed to modulate inflammation. Finally, pharmacological reactivation of Nrf2 can suppress the inflammation-mediated phenotypes and lethality of Dpf2Δ/Δ mice. Our work establishes the essential role of the Dpf2/BAF complex in licensing Nrf2-dependent gene expression in HSCs and immune effector cells to prevent chronic inflammation.
Gloria Mas, Na Man, Yuichiro Nakata, Concepcion Martinez-Caja, Daniel L. Karl, Felipe Beckedorff, Francesco Tamiro, Chuan Chen, Stephanie Duffort, Hidehiro Itonaga, Adnan K. Mookhtiar, Kranthi Kunkalla, Alfredo M. Valencia, Clayton K. Collings, Cigall Kadoch, Francisco Vega, Scott C. Kogan, Lluis Morey, Daniel Bilbao, Stephen D. Nimer
Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis (CH) of indeterminate potential (CHIP) is frequent in ageing, involves expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, risk factors that contribute to CHIP-associated CH are poorly understood. Obesity induces a pro-inflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data from 47,466 individuals with validated CHIP in UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1 and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and a pro-inflammatory state can potentiate progression of CHIP to more significant hematologic neoplasia. Calcium channel blocker, nifedipine or SKF-96365, either alone or in combination with metformin, MCC950 or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in obese individuals.
Santhosh Kumar Pasupuleti, Baskar Ramdas, Sarah S. Burns, Lakshmi Reddy Palam, Rahul Kanumuri, Ramesh Kumar, Taruni R. Pandhiri, Utpal Dave, Nanda Kumar Yellapu, Xinyu Zhou, Chi Zhang, George E. Sandusky, Zhi Yu, Michael C. Honigberg, Alexander G. Bick, Gabriel K. Griffin, Abhishek Niroula, Benjamin L. Ebert, Sophie Paczesny, Pradeep Natarajan, Reuben Kapur
Excessive Erythrocytosis (EE) is a major hallmark of patients suffering from chronic mountain sickness (CMS, Monge’s disease) and is responsible for major morbidity and even mortality in early adulthood. We took advantage of unique populations, one living at high altitude (Peru) showing EE, while another population, at the same altitude and region, shows no evidence of EE (non-CMS). Through RNA-seq, we identified and validated the function of a group of long non-coding RNA (lncRNAs) that regulate erythropoiesis in Monge’s disease but not in the non-CMS population. Among these lncRNAs is HIKER (Hypoxia Induced Kinase-mediated Erythropoietic Regulator)/LINC02228 which we showed plays a critical role in erythropoiesis in CMS cells. Under hypoxia, HIKER modulated CSNK2B (the regulatory subunit of Casein kinase 2). A down-regulation of HIKER down-regulated CSNK2B, remarkably reducing erythropoiesis (<70% reduction of BFUs); furthermore, an up-regulation of CSNK2B on the background of HIKER down-regulation rescued erythropoiesis defects. Pharmacologic inhibition of CSNK2B drastically reduced erythroid colonies (50-75% reduction in BFU colonies) and knock-down of CSNK2B in zebrafish lead to a defect in hemoglobinization (<97% morphants show reduction in hemoglobin levels). We conclude that HIKER regulates erythropoiesis in Monge’s disease and acts through at least one specific target, CSNK2B, a casein kinase.
Priti Azad, Dan Zhou, Hung-Chi Tu, Francisco C. Villafuerte, David Traver, Tariq M. Rana, Gabriel G. Haddad