Issue published November 15, 2022 Previous issue | Next issue
On the cover: Impaired DNA repair activates c-GAS/STING in pediatric glioma
Haase et al. report that H3.3-G34 mutations in pediatric high-grade glioma impair DNA repair, increasing susceptibility to DNA damage response inhibitors and inducing cGAS/STING-mediated immune responses. Image credit: Ella Marushchenko.
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Commentaries
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Abstract
Pediatric high-grade gliomas (pHGGs) are aggressive diseases with poor outcomes. The diverse molecular heterogeneity in these rare tumors and inadequate tumor models have limited the development of effective therapies. In this issue of the JCI, Haase et al. produced a genetically engineered mouse model of H3.3-G34R–mutant pHGG to help identify vulnerabilities in DNA repair pathways. The authors designed a therapy that combined radiation with DNA damage response inhibitors to induce an adaptive immune response and extend survival. These findings suggest that combinations of small-molecule therapies with immunotherapies could drive a more durable response and improve mortality for patients with pHGG.
Authors
Connor P. Hall, James C. Cronk, Jeffrey A. Rubens
×Abstract
Healthy individuals are generally immunologically tolerant to proteins derived from one’s self (termed self proteins). However, patients with monogenic clotting disorders, like hemophilia A (HemA), lack central tolerance to the absent self protein. Thus, when exposed to replacement therapy, such as procoagulant factor VIII, they may mount an immune response against the very self protein that is missing. In the current issue of the JCI, Becker-Gotot, Meissner, et al. present data on a possible mechanism for tolerance to factor VIII in healthy individuals and the immune response in patients, involving a role of PD-1 and T regulatory cells. The findings suggest that treatment with PD-1– and PD-1L–specific reagents may induce tolerance in patients with autoimmune disease, especially those with HemA who also possess inhibiting antibodies.
Authors
David W. Scott
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Research Articles
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Abstract
Preterm birth is the leading cause of death in children under 5 years of age. Premature infants who receive life-saving oxygen therapy often develop bronchopulmonary dysplasia (BPD), a chronic lung disease. Infants with BPD are at a high risk of abnormal neurodevelopment, including motor and cognitive difficulties. While neural progenitor cells (NPCs) are crucial for proper brain development, it is unclear whether they play a role in BPD-associated neurodevelopmental deficits. Here, we show that hyperoxia-induced experimental BPD in newborn mice led to lifelong impairments in cerebrovascular structure and function as well as impairments in NPC self-renewal and neurogenesis. A neurosphere assay utilizing nonhuman primate preterm baboon NPCs confirmed impairment in NPC function. Moreover, gene expression profiling revealed that genes involved in cell proliferation, angiogenesis, vascular autoregulation, neuronal formation, and neurotransmission were dysregulated following neonatal hyperoxia. These impairments were associated with motor and cognitive decline in aging hyperoxia-exposed mice, reminiscent of deficits observed in patients with BPD. Together, our findings establish a relationship between BPD and abnormal neurodevelopmental outcomes and identify molecular and cellular players of neonatal brain injury that persist throughout adulthood that may be targeted for early intervention to aid this vulnerable patient population.
Authors
Marissa A. Lithopoulos, Xavier Toussay, Shumei Zhong, Liqun Xu, Shamimunisa B. Mustafa, Julie Ouellette, Moises Freitas-Andrade, Cesar H. Comin, Hayam A. Bassam, Adam N. Baker, Yiren Sun, Michael Wakem, Alvaro G. Moreira, Cynthia L. Blanco, Arul Vadivel, Catherine Tsilfidis, Steven R. Seidner, Ruth S. Slack, Diane C. Lagace, Jing Wang, Baptiste Lacoste, Bernard Thébaud
×SIRT1 inactivation switches reactive astrocytes to an antiinflammatory phenotype in CNS autoimmunity
Abstract
Astrocytes are highly heterogeneous in their phenotype and function, which contributes to CNS disease, repair, and aging; however, the molecular mechanism of their functional states remains largely unknown. Here, we show that activation of sirtuin 1 (SIRT1), a protein deacetylase, played an important role in the detrimental actions of reactive astrocytes, whereas its inactivation conferred these cells with antiinflammatory functions that inhibited the production of proinflammatory mediators by myeloid cells and microglia and promoted the differentiation of oligodendrocyte progenitor cells. Mice with astrocyte-specific Sirt1 knockout (Sirt1–/–) had suppressed progression of experimental autoimmune encephalomyelitis (EAE), an animal model of CNS inflammatory demyelinating disease. Ongoing EAE was also suppressed when Sirt1 expression in astrocytes was diminished by a CRISPR/Cas vector, resulting in reduced demyelination, decreased numbers of T cells, and an increased rate of IL-10–producing macrophages and microglia in the CNS, whereas the peripheral immune response remained unaffected. Mechanistically, Sirt1–/– astrocytes expressed a range of nuclear factor erythroid–derived 2–like 2 (Nfe2l2) target genes, and Nfe2l2 deficiency shifted the beneficial action of Sirt1–/– astrocytes to a detrimental one. These findings identify an approach for switching the functional state of reactive astrocytes that will facilitate the development of astrocyte-targeting therapies for inflammatory neurodegenerative diseases such as multiple sclerosis.
Authors
Weifeng Zhang, Dan Xiao, Xing Li, Yuan Zhang, Javad Rasouli, Giacomo Casella, Alexandra Boehm, Daniel Hwang, Larissa L.W. Ishikawa, Rodolfo Thome, Bogoljub Ciric, Mark T. Curtis, Abdolmohamad Rostami, Guang-Xian Zhang
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Cisplatin is a potent chemotherapeutic drug that is widely used in the treatment of various solid cancers. However, its clinical effectiveness is strongly limited by frequent severe adverse effects, in particular nephrotoxicity and chemotherapy-induced peripheral neuropathy. Thus, there is an urgent medical need to identify novel strategies that limit cisplatin-induced toxicity. In the present study, we show that the FDA-approved adenosine A2A receptor antagonist istradefylline (KW6002) protected from cisplatin-induced nephrotoxicity and neuropathic pain in mice with or without tumors. Moreover, we also demonstrate that the antitumoral properties of cisplatin were not altered by istradefylline in tumor-bearing mice and could even be potentiated. Altogether, our results support the use of istradefylline as a valuable preventive approach for the clinical management of patients undergoing cisplatin treatment.
Authors
Edmone Dewaeles, Kévin Carvalho, Sandy Fellah, Jaewon Sim, Nihad Boukrout, Raphaelle Caillierez, Hariharan Ramakrishnan, Cynthia Van der Hauwaert, Jhenkruthi Vijaya Shankara, Nathalie Martin, Noura Massri, Agathe Launay, Joseph K. Folger, Clémentine de Schutter, Romain Larrue, Ingrid Loison, Marine Goujon, Matthieu Jung, Stéphanie Le Gras, Victoria Gomez-Murcia, Emilie Faivre, Julie Lemaire, Anne Garat, Nicolas Beauval, Patrice Maboudou, Viviane Gnemmi, Jean-Baptiste Gibier, Luc Buée, Corinne Abbadie, Francois Glowacki, Nicolas Pottier, Michael Perrais, Rodrigo A. Cunha, Jean-Sébastien Annicotte, Geoffroy Laumet, David Blum, Christelle Cauffiez
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Myeloid lineage cells suppress T cell viability through arginine depletion via arginase 1 (ARG1). Despite numerous studies exploring the mechanisms by which ARG1 perturbs lymphocyte function, the cellular populations responsible for its generation and release remain poorly understood. Here, we showed that neutrophil lineage cells and not monocytes or macrophages expressed ARG1 in human non–small cell lung cancer (NSCLC). Importantly, we showed that approximately 40% of tumor-associated neutrophils (TANs) actively transcribed ARG1 mRNA. To determine the mechanism by which ARG1 mRNA is induced in TANs, we utilized FPLC followed by MS/MS to screen tumor-derived factors capable of inducing ARG1 mRNA expression in neutrophils. These studies identified ANXA2 as the major driver of ARG1 mRNA expression in TANs. Mechanistically, ANXA2 signaled through the TLR2/MYD88 axis in neutrophils to induce ARG1 mRNA expression. The current study describes what we believe to be a novel mechanism by which ARG1 mRNA expression is regulated in neutrophils in cancer and highlights the central role that neutrophil lineage cells play in the suppression of tumor-infiltrating lymphocytes.
Authors
Huajia Zhang, Xiaodong Zhu, Travis J. Friesen, Jeff W. Kwak, Tatyana Pisarenko, Surapat Mekvanich, Mark A. Velasco, Timothy W. Randolph, Julia Kargl, A. McGarry Houghton
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Pediatric high-grade gliomas (pHGGs) are the leading cause of cancer-related deaths in children in the USA. Sixteen percent of hemispheric pediatric and young adult HGGs encode Gly34Arg/Val substitutions in the histone H3.3 (H3.3-G34R/V). The mechanisms by which H3.3-G34R/V drive malignancy and therapeutic resistance in pHGGs remain unknown. Using a syngeneic, genetically engineered mouse model (GEMM) and human pHGG cells encoding H3.3-G34R, we demonstrate that this mutation led to the downregulation of DNA repair pathways. This resulted in enhanced susceptibility to DNA damage and inhibition of the DNA damage response (DDR). We demonstrate that genetic instability resulting from improper DNA repair in G34R-mutant pHGG led to the accumulation of extrachromosomal DNA, which activated the cyclic GMP–AMP synthase/stimulator of IFN genes (cGAS/STING) pathway, inducing the release of immune-stimulatory cytokines. We treated H3.3-G34R pHGG–bearing mice with a combination of radiotherapy (RT) and DNA damage response inhibitors (DDRi) (i.e., the blood-brain barrier–permeable PARP inhibitor pamiparib and the cell-cycle checkpoint CHK1/2 inhibitor AZD7762), and these combinations resulted in long-term survival for approximately 50% of the mice. Moreover, the addition of a STING agonist (diABZl) enhanced the therapeutic efficacy of these treatments. Long-term survivors developed immunological memory, preventing pHGG growth upon rechallenge. These results demonstrate that DDRi and STING agonists in combination with RT induced immune-mediated therapeutic efficacy in G34-mutant pHGG.
Authors
Santiago Haase, Kaushik Banerjee, Anzar A. Mujeeb, Carson S. Hartlage, Fernando M. Núñez, Felipe J. Núñez, Mahmoud S. Alghamri, Padma Kadiyala, Stephen Carney, Marcus N. Barissi, Ayman W. Taher, Emily K. Brumley, Sarah Thompson, Justin T. Dreyer, Caitlin T. Alindogan, Maria B. Garcia-Fabiani, Andrea Comba, Sriram Venneti, Visweswaran Ravikumar, Carl Koschmann, Ángel M. Carcaboso, Maria Vinci, Arvind Rao, Jennifer S. Yu, Pedro R. Lowenstein, Maria G. Castro
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Cell surface receptors, ligands, and adhesion molecules underlie development, circuit formation, and synaptic function of the central nervous system and represent important therapeutic targets for many neuropathologies. The functional contributions of interactions between cell surface proteins of neurons and nonneuronal cells have not been fully addressed. Using an unbiased protein-protein interaction screen, we showed that the human immunomodulatory ligand B7-1 (hB7-1) interacts with the p75 neurotrophin receptor (p75NTR) and that the B7-1:p75NTR interaction is a recent evolutionary adaptation present in humans and other primates, but absent in mice, rats, and other lower mammals. The surface of hB7-1 that engages p75NTR overlaps with the hB7-1 surface involved in CTLA-4/CD28 recognition, and these molecules directly compete for binding to p75NTR. Soluble or membrane-bound hB7-1 altered dendritic morphology of cultured hippocampal neurons, with loss of the postsynaptic protein PSD95 in a p75NTR-dependent manner. Abatacept, an FDA-approved therapeutic (CTLA-4–hFc fusion) inhibited these processes. In vivo injection of hB7-1 into the murine subiculum, a hippocampal region affected in Alzheimer’s disease, resulted in p75NTR-dependent pruning of dendritic spines. Here, we report the biochemical interaction between B7-1 and p75NTR, describe biological effects on neuronal morphology, and identify a therapeutic opportunity for treatment of neuroinflammatory diseases.
Authors
Nicholas C. Morano, Roshelle S. Smith, Victor Danelon, Ryan Schreiner, Uttsav Patel, Natalia G. Herrera, Carla Smith, Steven M. Olson, Michelle K. Laerke, Alev Celikgil, Scott J. Garforth, Sarah C. Garrett-Thomson, Francis S. Lee, Barbara L. Hempstead, Steven C. Almo
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The CBFA2T3-GLIS2 (C/G) fusion is a product of a cryptic translocation primarily seen in infants and early childhood and is associated with dismal outcome. Here, we demonstrate that the expression of the C/G oncogenic fusion protein promotes the transformation of human cord blood hematopoietic stem and progenitor cells (CB HSPCs) in an endothelial cell coculture system that recapitulates the transcriptome, morphology, and immunophenotype of C/G acute myeloid leukemia (AML) and induces highly aggressive leukemia in xenograft models. Interrogating the transcriptome of C/G-CB cells and primary C/G AML identified a library of C/G-fusion-specific genes that are potential targets for therapy. We developed chimeric antigen receptor (CAR) T cells directed against one of the targets, folate receptor α (FOLR1), and demonstrated their preclinical efficacy against C/G AML using in vitro and xenograft models. FOLR1 is also expressed in renal and pulmonary epithelium, raising concerns for toxicity that must be addressed for the clinical application of this therapy. Our findings underscore the role of the endothelial niche in promoting leukemic transformation of C/G-transduced CB HSPCs. Furthermore, this work has broad implications for studies of leukemogenesis applicable to a variety of oncogenic fusion-driven pediatric leukemias, providing a robust and tractable model system to characterize the molecular mechanisms of leukemogenesis and identify biomarkers for disease diagnosis and targets for therapy.
Authors
Quy Le, Brandon Hadland, Jenny L. Smith, Amanda Leonti, Benjamin J. Huang, Rhonda Ries, Tiffany A. Hylkema, Sommer Castro, Thao T. Tang, Cyd N. McKay, LaKeisha Perkins, Laura Pardo, Jay Sarthy, Amy K. Beckman, Robin Williams, Rhonda Idemmili, Scott Furlan, Takashi Ishida, Lindsey Call, Shivani Srivastava, Anisha M. Loeb, Filippo Milano, Suzan Imren, Shelli M. Morris, Fiona Pakiam, Jim M. Olson, Michael R. Loken, Lisa Brodersen, Stanley R. Riddell, Katherine Tarlock, Irwin D. Bernstein, Keith R. Loeb, Soheil Meshinchi
×Abstract
Mutations in nuclear envelope proteins (NEPs) cause devastating genetic diseases, known as envelopathies, that primarily affect the heart and skeletal muscle. A mutation in the NEP LEM domain–containing protein 2 (LEMD2) causes severe cardiomyopathy in humans. However, the roles of LEMD2 in the heart and the pathological mechanisms responsible for its association with cardiac disease are unknown. We generated knockin (KI) mice carrying the human c.T38>G Lemd2 mutation, which causes a missense amino acid exchange (p.L13>R) in the LEM domain of the protein. These mice represent a preclinical model that phenocopies the human disease, as they developed severe dilated cardiomyopathy and cardiac fibrosis leading to premature death. At the cellular level, KI/KI cardiomyocytes exhibited disorganization of the transcriptionally silent heterochromatin associated with the nuclear envelope. Moreover, mice with cardiac-specific deletion of Lemd2 also died shortly after birth due to heart abnormalities. Cardiomyocytes lacking Lemd2 displayed nuclear envelope deformations and extensive DNA damage and apoptosis linked to p53 activation. Importantly, cardiomyocyte-specific Lemd2 gene therapy via adeno-associated virus rescued cardiac function in KI/KI mice. Together, our results reveal the essentiality of LEMD2 for genome stability and cardiac function and unveil its mechanistic association with human disease.
Authors
Xurde M. Caravia, Andres Ramirez-Martinez, Peiheng Gan, Feng Wang, John R. McAnally, Lin Xu, Rhonda Bassel-Duby, Ning Liu, Eric N. Olson
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Subcutaneous phaeohyphomycosis typically affects immunocompetent individuals following traumatic inoculation. Severe or disseminated infection can occur in CARD9 deficiency or after transplantation, but the mechanisms protecting against phaeohyphomycosis remain unclear. We evaluated a patient with progressive, refractory Corynespora cassiicola phaeohyphomycosis and found that he carried biallelic deleterious mutations in CLEC7A encoding the CARD9-coupled, β-glucan–binding receptor, Dectin-1. The patient’s PBMCs failed to produce TNF-α and IL-1β in response to β-glucan and/or C. cassiicola. To confirm the cellular and molecular requirements for immunity against C. cassiicola, we developed a mouse model of this infection. Mouse macrophages required Dectin-1 and CARD9 for IL-1β and TNF-α production, which enhanced fungal killing in an interdependent manner. Deficiency of either Dectin-1 or CARD9 was associated with more severe fungal disease, recapitulating the human observation. Because these data implicated impaired Dectin-1 responses in susceptibility to phaeohyphomycosis, we evaluated 17 additional unrelated patients with severe forms of the infection. We found that 12 out of 17 carried deleterious CLEC7A mutations associated with an altered Dectin-1 extracellular C-terminal domain and impaired Dectin-1–dependent cytokine production. Thus, we show that Dectin-1 and CARD9 promote protective TNF-α– and IL-1β–mediated macrophage defense against C. cassiicola. More broadly, we demonstrate that human Dectin-1 deficiency may contribute to susceptibility to severe phaeohyphomycosis by certain dematiaceous fungi.
Authors
Rebecca A. Drummond, Jigar V. Desai, Amy P. Hsu, Vasileios Oikonomou, Donald C. Vinh, Joshua A. Acklin, Michael S. Abers, Magdalena A. Walkiewicz, Sarah L. Anzick, Muthulekha Swamydas, Simon Vautier, Mukil Natarajan, Andrew J. Oler, Daisuke Yamanaka, Katrin D. Mayer-Barber, Yoichiro Iwakura, David Bianchi, Brian Driscoll, Ken Hauck, Ahnika Kline, Nicholas S.P. Viall, Christa S. Zerbe, Elise M.N. Ferré, Monica M. Schmitt, Tom DiMaggio, Stefania Pittaluga, John A. Butman, Adrian M. Zelazny, Yvonne R. Shea, Cesar A. Arias, Cameron Ashbaugh, Maryam Mahmood, Zelalem Temesgen, Alexander G. Theofiles, Masayuki Nigo, Varsha Moudgal, Karen C. Bloch, Sean G. Kelly, M. Suzanne Whitworth, Ganesh Rao, Cindy J. Whitener, Neema Mafi, Juan Gea-Banacloche, Lawrence C. Kenyon, William R. Miller, Katia Boggian, Andrea Gilbert, Matthew Sincock, Alexandra F. Freeman, John E. Bennett, Rodrigo Hasbun, Constantinos M. Mikelis, Kyung J. Kwon-Chung, Yasmine Belkaid, Gordon D. Brown, Jean K. Lim, Douglas B. Kuhns, Steven M. Holland, Michail S. Lionakis
×Abstract
Prevalent copy number alteration is the most prominent genetic characteristic associated with ovarian cancer (OV) development, but its role in immune evasion has not been fully elucidated. In this study, we identified RAD21, a key component of the cohesin complex, as a frequently amplified oncogene that could modulate immune response in OV. Through interrogating the RAD21-regulated transcriptional program, we found that RAD21 directly interacts with YAP/TEAD4 transcriptional corepressors and recruits the NuRD complex to suppress interferon (IFN) signaling. In multiple clinical cohorts, RAD21 overexpression is inversely correlated with IFN signature gene expression in OV. We further demonstrated in murine syngeneic tumor models that RAD21 ablation potentiated anti–PD-1 efficacy with increased intratumoral CD8+ T cell effector activity. Our study identifies a RAD21–YAP/TEAD4–NuRD corepressor complex in immune modulation, and thus provides a potential target and biomarker for precision immunotherapy in OV.
Authors
Peng Deng, Zining Wang, Jinghong Chen, Shini Liu, Xiaosai Yao, Shaoyan Liu, Lizhen Liu, Zhaoliang Yu, Yulin Huang, Zhongtang Xiong, Rong Xiao, Jiuping Gao, Weiting Liang, Jieping Chen, Hui Liu, Jing Han Hong, Jason Yongsheng Chan, Peiyong Guan, Jianfeng Chen, Yali Wang, Jiaxin Yin, Jundong Li, Min Zheng, Chao Zhang, Penghui Zhou, Tiebang Kang, Bin Tean Teh, Qiang Yu, Zhixiang Zuo, Qingping Jiang, Jihong Liu, Ying Xiong, Xiaojun Xia, Jing Tan
×Abstract
A major complication of hemophilia A therapy is the development of alloantibodies (inhibitors) that neutralize intravenously administered coagulation factor VIII (FVIII). Immune tolerance induction therapy (ITI) by repetitive FVIII injection can eradicate inhibitors, and thereby reduce morbidity and treatment costs. However, ITI success is difficult to predict and the underlying immunological mechanisms are unknown. Here, we demonstrated that immune tolerance against FVIII under nonhemophilic conditions was maintained by programmed death (PD) ligand 1–expressing (PD-L1–expressing) regulatory T cells (Tregs) that ligated PD-1 on FVIII-specific B cells, causing them to undergo apoptosis. FVIII-deficient mice injected with FVIII lacked such Tregs and developed inhibitors. Using an ITI mouse model, we found that repetitive FVIII injection induced FVIII-specific PD-L1+ Tregs and reengaged removal of inhibitor-forming B cells. We also demonstrated the existence of FVIII-specific Tregs in humans and showed that such Tregs upregulated PD-L1 in patients with hemophilia after successful ITI. Simultaneously, FVIII-specific B cells upregulated PD-1 and became killable by Tregs. In summary, we showed that PD-1–mediated B cell tolerance against FVIII operated in healthy individuals and in patients with hemophilia A without inhibitors, and that ITI reengaged this mechanism. These findings may impact monitoring of ITI success and treatment of patients with hemophilia A.
Authors
Janine Becker-Gotot, Mirjam Meissner, Vadim Kotov, Blanca Jurado-Mestre, Andrea Maione, Andreas Pannek, Thilo Albert, Chrystel Flores, Frank A. Schildberg, Paul A. Gleeson, Birgit M. Reipert, Johannes Oldenburg, Christian Kurts
×Abstract
22q11.2 deletion syndrome (22q11.2DS) is the most common human chromosomal microdeletion, causing developmentally linked congenital malformations, thymic hypoplasia, hypoparathyroidism, and/or cardiac defects. Thymic hypoplasia leads to T cell lymphopenia, which most often results in mild SCID. Despite decades of research, the molecular underpinnings leading to thymic hypoplasia in 22q11.2DS remain unknown. Comparison of embryonic thymuses from mouse models of 22q11.2DS (Tbx1neo2/neo2) revealed proportions of mesenchymal, epithelial, and hematopoietic cell types similar to those of control thymuses. Yet, the small thymuses were growth restricted in fetal organ cultures. Replacement of Tbx1neo2/neo2 thymic mesenchymal cells with normal ones restored tissue growth. Comparative single-cell RNA-Seq of embryonic thymuses uncovered 17 distinct cell subsets, with transcriptome differences predominant in the 5 mesenchymal subsets from the Tbx1neo2/neo2 cell line. The transcripts affected included those for extracellular matrix proteins, consistent with the increased collagen deposition we observed in the small thymuses. Attenuating collagen cross-links with minoxidil restored thymic tissue expansion for hypoplastic lobes. In colony-forming assays, the Tbx1neo2/neo2-derived mesenchymal cells had reduced expansion potential, in contrast to the normal growth of thymic epithelial cells. These findings suggest that mesenchymal cells were causal to the small embryonic thymuses in the 22q11.2DS mouse models, which was correctable by substitution with normal mesenchyme.
Authors
Pratibha Bhalla, Qiumei Du, Ashwani Kumar, Chao Xing, Angela Moses, Igor Dozmorov, Christian A. Wysocki, Ondine B. Cleaver, Timothy J. Pirolli, Mary Louise Markert, Maria Teresa de la Morena, Antonio Baldini, Nicolai S.C. van Oers
×Abstract
Mutational activation of KRAS is a common oncogenic event in lung cancer, yet effective therapies are still lacking. Here, we identify B cell lymphoma 6 (BCL6) as a lynchpin in KRAS-driven lung cancer. BCL6 expression was increased upon KRAS activation in lung tumor tissue in mice and was positively correlated with the expression of KRAS-GTP, the active form of KRAS, in various human cancer cell lines. Moreover, BCL6 was highly expressed in human KRAS-mutant lung adenocarcinomas and was associated with poor patient survival. Mechanistically, the MAPK/ERK/ELK1 signaling axis downstream of mutant KRAS directly regulated BCL6 expression. BCL6 maintained the global expression of prereplication complex components; therefore, BCL6 inhibition induced stalling of the replication fork, leading to DNA damage and growth arrest in KRAS-mutant lung cancer cells. Importantly, BCL6-specific knockout in lungs significantly reduced the tumor burden and mortality in the LSL-KrasG12D/+ lung cancer mouse model. Likewise, pharmacological inhibition of BCL6 significantly impeded the growth of KRAS-mutant lung cancer cells both in vitro and in vivo. In summary, our findings reveal a crucial role of BCL6 in promoting KRAS-addicted lung cancer and suggest BCL6 as a therapeutic target for the treatment of this intractable disease.
Authors
Kun Li, Yanan Liu, Yi Ding, Zhengwei Zhang, Juanjuan Feng, Jiaxin Hu, Jiwei Chen, Zhengke Lian, Yiliang Chen, Kewen Hu, Zhi Chen, Zhenyu Cai, Mingyao Liu, Xiufeng Pang
×Abstract
Cancer immunotherapy targeting the TIGIT/PVR pathway is currently facing challenges. KIR2DL5, a member of the human killer cell, immunoglobulin-like receptor (KIR) family, has recently been identified as another binding partner for PVR. The biology and therapeutic potential of the KIR2DL5/PVR pathway are largely unknown. Here we report that KIR2DL5 was predominantly expressed on human NK cells with mature phenotype and cytolytic function and that it bound to PVR without competition with the other 3 known PVR receptors. The interaction between KIR2DL5 on NK cells and PVR on target cells induced inhibitory synapse formation, whereas new monoclonal antibodies blocking the KIR2DL5-PVR interaction robustly augmented the NK cytotoxicity against PVR+ human tumors. Mechanistically, both intracellular ITIM and ITSM of KIR2DL5 underwent tyrosine phosphorylation after engagement, which was essential for KIR2DL5-mediated NK suppression by recruiting SHP-1 and/or SHP-2. Subsequently, ITIM/SHP-1/SHP-2 and ITSM/SHP-1 downregulated the downstream Vav1/ERK1/2/p90RSK/NF-κB signaling. KIR2DL5+ immune cells infiltrated in various types of PVR+ human cancers. Markedly, the KIR2DL5 blockade reduced tumor growth and improved overall survival across multiple NK cell–based humanized tumor models. Thus, our results revealed functional mechanisms of KIR2DL5-mediated NK cell immune evasion, demonstrated blockade of the KIR2DL5/PVR axis as a therapy for human cancers, and provided an underlying mechanism for the clinical failure of anti-TIGIT therapies.
Authors
Xiaoxin Ren, Mou Peng, Peng Xing, Yao Wei, Phillip M. Galbo Jr., Devin Corrigan, Hao Wang, Yingzhen Su, Xiaoshen Dong, Qizhe Sun, Yixian Li, Xiaoyu Zhang, Winfried Edelmann, Deyou Zheng, Xingxing Zang
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)