Stapley et al. generated a conditional mouse model to assess the role of Schlafen 14 (SLFN14) in platelets and megakaryocytes (MKs) and to better understand the molecular mechanisms driving the bleeding phenotype in humans with SLFN14 mutations. The cover shows a transmission electron micrograph of enlarged platelets from a murine model with a platelet- and MK-specific Slfn14 deletion.
Infiltration of T-cell acute lymphoblastic leukemia (T-ALL) into the meninges worsens prognosis, underscoring the need to understand mechanisms driving meningeal involvement. Here, we show that T-ALL cells expressing CXCR3 exploit normal T-cell function to infiltrate the inflamed meninges. CXCR3 deletion hampered disease progression and extramedullary dissemination by reducing leukemic cell proliferation and migration. Conversely, forced expression of CXCR3 facilitated T-ALL trafficking to the meninges. We identified the ubiquitin-specific protease 7 as a key regulator of CXCR3 protein stability in T-ALL. Furthermore, we discovered elevated levels of CXCL10, a CXCR3 ligand, in the cerebrospinal fluid from T-ALL patients and leukemia-bearing mice. Our studies demonstrate that meningeal stromal cells, specifically pericytes and fibroblasts, induce CXCL10 expression in response to leukemia, and that loss of CXCL10 attenuated T-ALL influx into the meninges. Moreover, we report that leukemia-derived proinflammatory cytokines, TNFα, IL27 and IFNγ, induced CXCL10 in the meningeal stroma. Pharmacological inhibition or deletion of CXCR3 or CXCL10 reduced T-ALL cell migration and adhesion to meningeal stromal cells. Finally, we reveal that CXCR3 and CXCL10 upregulated VLA-4/VCAM-1 signaling, promoting cell-cell adhesion and thus T-ALL retention in the meninges. Our findings highlight the pivotal role of CXCR3-CXCL10 signaling in T-ALL progression and meningeal colonization.
Nitesh D. Sharma, Esra'a Keewan, Wojciech Ornatowski, Silpita Paul, Monique Nysus, Christopher C. Barnett, Julie Wolfson, Quiteria Jacquez, Bianca L. Myers, Huining Kang, Katherine E. Zychowski, Stuart S. Winter, Mignon L. Loh, Stephen P. Hunger, Eliseo F. Castillo, Tom Taghon, Christina Halsey, Tou Yia Vue, Nicholas Jones, Panagiotis Ntziachristos, Ksenia Matlawska-Wasowska
There is an urgent need to find targeted agents for T-cell acute lymphoblastic leukemia (T-ALL). NOTCH1 is the most frequently mutated oncogene in T-ALL, but clinical trials showed that pan-Notch inhibitors caused dose-limiting toxicities. Thus, we shifted our focus to ETS1, which is one of the transcription factors that most frequently co-bind Notch-occupied regulatory elements in the T-ALL context. To identify the most essential enhancers, we performed a genome-wide CRISPR interference screen of the strongest ETS1-dependent regulatory elements. The #1-ranked element is located in an intron of AHI1 that interacts with the MYB promoter and is amplified with MYB in ~8.5% of T-ALL patients. Using mouse models, we showed that this enhancer promotes self-renewal of hematopoietic stem cells and T-cell leukemogenesis, maintains early T-cell precursors, and restrains myeloid expansion with aging. We named this enhancer the hematopoietic stem cell MYB enhancer (H-Me). The H-Me shows limited activity and function in committed T-cell progenitors but is accessed during leukemogenesis. In one T-ALL context, ETS1 binds the ETS motif in the H-Me to recruit cBAF to promote chromatin accessibility and activation. ETS1 or cBAF degraders impaired H-Me function. Thus, we identified a targetable stem cell element that is co-opted for T-cell transformation.
Carea Mullin, Karena Lin, Elizabeth Choe, Cher Sha, Zeel Shukla, Koral Campbell, Anna C. McCarter, Annie Wang, Jannaldo Nieves-Salva, Sarah Khan, Theresa M. Keeley, Shannon Liang, Qing Wang, Ashley F. Melnick, Pearl Evans, Alexander C. Monovich, Ashwin Iyer, Rohan Kodgule, Yamei Deng, Felipe da Veiga Leprevost, Kelly R. Barnett, Petri Pölönen, Rami Khoriaty, Daniel Savic, David T. Teachey, Charles G. Mullighan, Marcin Cieslik, Alexey I. Nesvizhskii, Linda C. Samuelson, Morgan Jones, Qing Li, Russell J.H. Ryan, Mark Y. Chiang
Isin Y. Comba, Tijs Louwies, Ruben A. Mars, Yang Xiao, Prabhjot Kaur Sekhon, Brian S. Edwards, Adam Willits, Robin R. Shields-Cutler, Shreya Bellampalli, Arnaldo Mercado-Perez, Dennis R. Tienter, Lisa M. Till, David R. Linden, Gianrico Farrugia, Arthur Beyder, Kristen M. Smith-Edwards, Purna C. Kashyap
The increased prevalence of GluA2-lacking, Ca2+-permeable AMPA receptors (CP-AMPARs) at spinal cord sensory synapses amplifies nociceptive transmission and maintains chronic neuropathic pain. Nerve injury–induced upregulation of α2δ-1 disrupts the assembly of GluA1/GluA2 heteromers, favoring the synaptic incorporation of GluA1 homotetramers in the spinal dorsal horn. Although GluA1-GluA3 subunits are broadly expressed, whether α2δ-1 regulates GluA3-containing AMPARs remains unknown. Here, we unexpectedly found that coexpression with α2δ-1—but not α2δ-2 or α2δ-3—diminished GluA3 AMPAR currents and protein levels, an effect blocked by pregabalin, an α2δ-1 C-terminus peptide, or proteasome inhibition. Both nerve injury and α2δ-1 overexpression reduced protein levels of GluA3 and GluA2/GluA3 heteromers in the spinal cord. Furthermore, α2δ-1 coexpression or nerve injury increased GluA3 ubiquitination, with Lys-861 at the C terminus of GluA3 identified as a key ubiquitination site mediating α2δ-1–induced GluA3 degradation. Additionally, intrathecal delivery of the Gria3 gene reversed nerve injury–induced nociceptive hypersensitivity and synaptic CP-AMPARs by restoring protein levels of GluA3 and GluA2/GluA3 heteromers in the spinal cord. These findings reveal that α2δ-1 promotes GluA1 homotetramer assembly and synaptic CP-AMPAR expression by driving ubiquitin-proteasomal degradation of GluA3, providing insights into the molecular mechanisms of neuropathic pain and the therapeutic actions of gabapentinoids.
Meng-Hua Zhou, Shao-Rui Chen, Daozhong Jin, Yuying Huang, Hong Chen, Guanxing Chen, Jiusheng Yan, Hui-Lin Pan
Harnessing the stimulator of interferon genes (STING) signaling pathway to trigger innate immune responses has shown remarkable promise in cancer immunotherapy; however, overwhelming resistance to intratumoral STING monotherapy has been witnessed in clinical trials, and the underlying mechanisms remain to be fully explored. Herein, we show that pharmacological STING activation following the intratumoral injection of a non-nucleotide STING agonist (i.e., MSA-2) results in apoptosis of the cytolytic T cells, interferon-mediated overexpression of indoleamine 2,3-dioxygenase 1 (IDO1), and evasion from immune surveillance. We leverage a noncovalent chemical strategy for developing immunomodulatory binary nanoparticles (iBINP) that include both the STING agonist and an IDO1 inhibitor for treating immune-evasive tumors. This iBINP platform developed by dual prodrug engineering and subsequent nanoparticle assembly enables tumor-restricted STING activation and IDO1 inhibition, achieving immune activation while mitigating immune tolerance. A systemic treatment of preclinical models of colorectal cancer with iBINP resulted in robust antitumor immune responses, reduced infiltration of regulatory T cells, and enhanced activity of CD8+ T cells. Importantly, this platform exhibits great therapeutic efficacy by overcoming STING–induced immune evasion and controlling the progression of multiple tumor models. This study unveils the mechanisms by which STING monotherapy induces immunosuppression in the tumor microenvironment and provides a combinatorial strategy for advancing cancer immunotherapies.
Fanchao Meng, Hengyan Zhu, Shuo Wu, Bohan Li, Xiaona Chen, Hangxiang Wang
Pancreatic ductal adenocarcinoma (PDAC) has among the poorest prognosis and highest refractory rates of all tumor types. The reviews in this series, by Dr. Ben Z. Stanger, bring together experts across multiple disciplines to explore what makes PDAC and other pancreatic cancers so distinctively challenging and provide an update on recent multipronged approaches aimed at improving early diagnosis and treatment.
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