Notch 1/2 genes play tumor-suppressing functions in squamous cell carcinoma (SCC), a very common malignancy in skin and internal organs. In contrast with Notch, we show that the transcription factor CSL (also known as RBP-Jκ), a key effector of canonical Notch signaling endowed with intrinsic transcription-repressive functions, plays a tumor-promoting function in SCC development. Expression of this gene decreased in upper epidermal layers and human keratinocytes (HKCs) undergoing differentiation, while it increased in premalignant and malignant SCC lesions from skin, head/neck, and lung. Increased CSL levels enhanced the proliferative potential of HKCs and SCC cells, while silencing of CSL induced growth arrest and apoptosis. In vivo, SCC cells with increased CSL levels gave rise to rapidly expanding tumors, while cells with silenced CSL formed smaller and more differentiated tumors with enhanced inflammatory infiltrate. Global transcriptomic analysis of HKCs and SCC cells with silenced CSL revealed major modulation of apoptotic, cell-cycle, and proinflammatory genes. We also show that the histone demethylase KDM6B is a direct CSL-negative target, with inverse roles of CSL in HKC and SCC proliferative capacity, tumorigenesis, and tumor-associated inflammatory reaction. CSL/KDM6B protein expression could be used as a biomarker of SCC development and indicator of cancer treatment.
Dania Al Labban, Seung-Hee Jo, Paola Ostano, Chiara Saglietti, Massimo Bongiovanni, Renato Panizzon, G. Paolo Dotto
Little is known about the repertoire dynamics and persistence of pathogenic T cells in HLA-associated disorders. In celiac disease, a disorder with a strong association with certain HLA-DQ allotypes, presumed pathogenic T cells can be visualized and isolated with HLA-DQ:gluten tetramers, thereby enabling further characterization. Single and bulk populations of HLA-DQ:gluten tetramer–sorted CD4+ T cells were analyzed by high-throughput DNA sequencing of rearranged TCR-α and -β genes. Blood and gut biopsy samples from 21 celiac disease patients, taken at various stages of disease and in intervals of weeks to decades apart, were examined. Persistence of the same clonotypes was seen in both compartments over decades, with up to 53% overlap between samples obtained 16 to 28 years apart. Further, we observed that the recall response following oral gluten challenge was dominated by preexisting CD4+ T cell clonotypes. Public features were frequent among gluten-specific T cells, as 10% of TCR-α, TCR-β, or paired TCR-αβ amino acid sequences of total 1813 TCRs generated from 17 patients were observed in 2 or more patients. In established celiac disease, the T cell clonotypes that recognize gluten are persistent for decades, making up fixed repertoires that prevalently exhibit public features. These T cells represent an attractive therapeutic target.
Louise F. Risnes, Asbjørn Christophersen, Shiva Dahal-Koirala, Ralf S. Neumann, Geir K. Sandve, Vikas K. Sarna, Knut E.A. Lundin, Shuo-Wang Qiao, Ludvig M. Sollid
Critical immune-suppressive pathways beyond programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) require greater attention. Nectins and nectin-like molecules might be promising targets for immunotherapy, since they play critical roles in cell proliferation and migration and exert immunomodulatory functions in pathophysiological conditions. Here, we show CD155 expression in both malignant cells and tumor-infiltrating myeloid cells in humans and mice. Cd155–/– mice displayed reduced tumor growth and metastasis via DNAM-1 upregulation and enhanced effector function of CD8+ T and NK cells, respectively. CD155-deleted tumor cells also displayed slower tumor growth and reduced metastases, demonstrating the importance of a tumor-intrinsic role of CD155. CD155 absence on host and tumor cells exerted an even greater inhibition of tumor growth and metastasis. Blockade of PD-1 or both PD-1 and CTLA4 was more effective in settings in which CD155 was limiting, suggesting the clinical potential of cotargeting PD-L1 and CD155 function.
Xian-Yang Li, Indrajit Das, Ailin Lepletier, Venkateswar Addala, Tobias Bald, Kimberley Stannard, Deborah Barkauskas, Jing Liu, Amelia Roman Aguilera, Kazuyoshi Takeda, Matthias Braun, Kyohei Nakamura, Sebastien Jacquelin, Steven W. Lane, Michele W.L. Teng, William C. Dougall, Mark J. Smyth
Eya proteins are critical developmental regulators that are highly expressed in embryogenesis but downregulated after development. Amplification and/or re-expression of Eyas occurs in many tumor types. In breast cancer, Eyas regulate tumor progression by acting as transcriptional cofactors and tyrosine phosphatases. Intriguingly, Eyas harbor a separate threonine (Thr) phosphatase activity, which was previously implicated in innate immunity. Here we describe what we believe to be a novel role for Eya3 in mediating triple-negative breast cancer–associated immune suppression. Eya3 loss decreases tumor growth in immune-competent mice and is associated with increased numbers of infiltrated CD8+ T cells, which, when depleted, reverse the effects of Eya3 knockdown. Mechanistically, Eya3 utilizes its Thr phosphatase activity to dephosphorylate Myc at pT58, resulting in a stabilized form. We show that Myc is required for Eya3-mediated increases in PD-L1, and that rescue of PD-L1 in Eya3-knockdown cells restores tumor progression. Finally, we demonstrate that Eya3 significantly correlates with PD-L1 in human breast tumors, and that tumors expressing high levels of Eya3 have a decreased CD8+ T cell signature. Our data uncover a role for Eya3 in mediating tumor-associated immune suppression, and suggest that its inhibition may enhance checkpoint therapies.
Rebecca L. Vartuli, Hengbo Zhou, Lingdi Zhang, Rani K. Powers, Jared Klarquist, Pratyaydipta Rudra, Melanie Y. Vincent, Debashis Ghosh, James C. Costello, Ross M. Kedl, Jill E. Slansky, Rui Zhao, Heide L. Ford
Tumor Necrosis Factor (TNF) is an important mediator in numerous inflammatory diseases, e.g., in inflammatory bowel diseases (IBD). In IBD, acute increases in TNF production can lead to disease flares. Glucocorticoids (GCs), which are steroids that bind and activate the glucocorticoid receptor (GR), are able to protect animals and humans against acute TNF-induced inflammatory symptoms. Mice with a poor transcriptional response of GR-dimer-dependent target genes were studied in a model of TNF-induced lethal inflammation. In contrast to the GRwt/wt mice, these GRdim/dim mice displayed a significant increase in TNF sensitivity and a lack of protection by the GC dexamethasone (DEX). Unchallenged GRdim/dim mice had a strong interferon-stimulated gene (ISG) signature, along with STAT1 upregulation and phosphorylation. This ISG signature was gut specific and, based on our studies with antibiotics, depended on the gut microbiota. GR dimers directly bound to short DNA sequences in the STAT1 promoter known as inverted repeat negative GRE (IR-nGRE) elements. Poor control of STAT1 in GRdim/dim mice led to failure to repress ISG genes resulting in excessive necroptosis induction by TNF. Our findings support a critical interplay between gut microbiota, interferons, necroptosis and GR in both the basal response to acute inflammatory challenges and in the pharmacological intervention by GCs.
Marlies Ballegeer, Kelly Van Looveren, Steven Timmermans, Melanie Eggermont, Sofie Vandevyver, Fabien Thery, Karen Dendoncker, Jolien Souffriau, Jolien Vandewalle, Lise Van Wyngene, Riet De Rycke, Nozomi Takahashi, Peter Vandenabeele, Jan Tuckermann, Holger M. Reichardt, Francis Impens, Rudi Beyaert, Karolien De Bosscher, Roosmarijn E. Vandenbroucke, Claude Libert
Kaposi’s sarcoma–associated herpesvirus (KSHV) is a gammaherpesvirus that is the etiological agent of the endothelial cell cancer Kaposi’s sarcoma (KS) and 2 B cell lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman’s disease (MCD). KSHV ORF36, also known as viral protein kinase (vPK), is a viral serine/threonine kinase. We previously reported that KSHV vPK enhances cell proliferation and mimics cellular S6 kinase to phosphorylate ribosomal protein S6, a protein involved in protein synthesis. We created a mouse model to analyze the function of vPK in vivo. We believe this is the first mouse tumor model of a viral kinase encoded by a pathogenic human virus. We observed increased B cell activation in the vPK transgenic mice compared with normal mice. We also found that, over time, vPK transgenic mice developed a B cell hyperproliferative disorder and/or a high-grade B cell non-Hodgkin lymphoma at a greatly increased incidence compared with littermate controls. This mouse model shows that a viral protein kinase is capable of promoting B cell activation and proliferation as well as augmenting lymphomagenesis in vivo and may therefore contribute to the development of viral cancers.
Penny M. Anders, Nathan D. Montgomery, Stephanie A. Montgomery, Aadra P. Bhatt, Dirk P. Dittmer, Blossom Damania
While the transcription factor forkhead box M1 (FOXM1) is well known as a proto-oncogene, its potential role in lung fibroblast activation has never been explored. Here, we show that FOXM1 is more highly expressed in fibrotic than in normal lung fibroblasts in humans and mice. FOXM1 was required not only for cell proliferation in response to mitogens, but also for myofibroblast differentiation and apoptosis resistance elicited by TGF-β. The lipid mediator PGE2, acting via cAMP signaling, was identified as an endogenous negative regulator of FOXM1. Finally, genetic deletion of FOXM1 in fibroblasts or administration of the FOXM1 inhibitor Siomycin A in a therapeutic protocol attenuated bleomycin-induced pulmonary fibrosis. Our results identify FOXM1 as a driver of lung fibroblast activation and underscore the therapeutic potential of targeting FOXM1 for pulmonary fibrosis.
Loka R. Penke, Jennifer M. Speth, Vijaya L. Dommeti, Eric S. White, Ingrid L. Bergin, Marc Peters-Golden
Many Toll-like receptors (TLRs) signal through TNF receptor–associated factor 6 (TRAF6) to activate innate immune responses. Here, we show that somatic nuclear autoantigenic sperm protein (sNASP) binds to TRAF6 to prevent TRAF6 autoubiquitination in unstimulated macrophages. Following LPS stimulation, a complex consisting of sNASP, TRAF6, IRAK4, and casein kinase 2 (CK2) is formed. CK2 phosphorylates sNASP at serine 158, allowing sNASP to dissociate from TRAF6. Free TRAF6 is then autoubiquitinated, followed by activation of downstream signaling pathways. In sNasp S158A knockin (S158A-KI) mice, LPS-treated macrophages could not phosphorylate sNASP, which remained bound to TRAF6. S158A-KI mice were more susceptible to sepsis due to a marked reduction in IL-1β, TNF-α, and IFN-γ production accompanied by an inability to clear bacteria and recruit leukocytes. Furthermore, phosphorylation-regulated release of sNASP from TRAF6 is observed following activation of TLR-1, -2, -4, -5, and -6. Thus, sNASP is a negative regulator of TLR signaling to modulate the innate immune response.
Feng-Ming Yang, Yong Zuo, Wei Zhou, Chuan Xia, Bumsuk Hahm, Mark Sullivan, Jinke Cheng, Hui-Ming Chang, Edward T.H. Yeh
Haemostasis requires conversion of fibrinogen to fibrin fibres that generate a characteristic network, interact with blood cells, and initiate tissue repair. The fibrin network is porous and highly permeable, but the spatial arrangement of the external clot face is unknown. Here we show that fibrin transitioned to the blood-air interface through Langmuir film formation, producing a protective film confining the clot. We demonstrated that only fibrin is required to form the film, and that it occurred in vitro and in vivo. The fibrin film connected to the underlying clot network through tethering fibres. It was digested by plasmin and formation of the film was prevented with surfactants. Functionally, the film retained blood cells and protected against penetration by bacterial pathogens in a murine model of dermal infection. Our data show a remarkable aspect of blood clotting, in which fibrin forms a protective film covering the external surface of the clot, defending the organism against microbial invasion.
Fraser L. Macrae, Cédric Duval, Praveen Papareddy, Stephen R. Baker, Nadira Yuldasheva, Katherine J. Kearney, Helen R. McPherson, Nathan Asquith, Joke Konings, Alessandro Casini, Jay L. Degen, Simon D. Connell, Helen Philippou, Alisa S. Wolberg, Heiko Herwald, Robert A.S. Ariëns
Receptor tyrosine kinases (RTKs) are important drivers of cancers. In addition to genomic alterations, aberrant activation of wild type RTKs plays an important role in driving cancer progression. However, the underlying mechanisms of how RTKs drive prostate cancer remain incompletely characterized. Here we show that non-proteolytic ubiquitination of RTK regulates its kinase activity and contributes to RTK-mediated prostate cancer metastasis. TRAF4, an E3 ubiquitin ligase, is highly expressed in metastatic prostate cancer. We demonstrated here that it is a key player in regulating RTK mediated prostate cancer metastasis. We further identified TrkA, a neurotrophin RTK, as TRAF4-targeted ubiquitination substrate that promotes cancer cell invasion and inhibition of TrkA activity abolished TRAF4-dependent cell invasion. TRAF4 promoted K27 and K29-linked ubiquitination at the TrkA kinase domain and increased its kinase activity. Mutation of TRAF4-targeted ubiquitination sites abolished TrkA tyrosine auto-phosphorylation and its interaction with downstream proteins. TRAF4 knockdown also suppressed NGF-stimulated TrkA downstream p38 MAPK activation and invasion-associated gene expression. Furthermore, elevated TRAF4 levels significantly correlated with increased NGF-stimulated invasion-associated gene expression in prostate cancer patients, indicating that this signaling axis is significantly activated during oncogenesis. Our results revealed a post-translational modification mechanism contributing to aberrant non-mutated RTK activation in cancer cells.
Ramesh Singh, Dileep Karri, Hong Shen, Jiangyong Shao, Subhamoy Dasgupta, Shixia Huang, Dean P. Edwards, Michael M. Ittmann, Bert W. O’Malley, Ping Yi