A novel GPI-anchored dominant-negative TGF-ß receptor II renders T cells unresponsive to TGF-ß signaling.

Transforming growth factor ß (TGF-ß) is a pleiotropic cytokine expressed by a wide range of cell types and is known for hampering the effectiveness of cancer immune cell therapeutic approaches. We have designed a novel construct containing the extracellular domain of the TGF-ß receptor II linked to a glycosylphosphatidylinositol (GPI) anchor (GPI-ecto-TßRII) lacking the transmembrane and cytoplasmic signaling domain of TGF-ß receptor II (TßRII). T cells transduced with lentivirus expressing the GPI-ecto-TßRII construct show 5 to 15 times higher membrane expression compared with a previously established dominant-negative receptor carrying a truncated signaling domain. GPI-ecto-TßRII expression renders T cells unresponsive to TGF-ß-induced signaling seen by a lack of SMAD phosphorylation upon exogeneous TGF-ß treatment. Transduced T cells continue to express high levels of IFNγ and granulocyte-macrophage colony-stimulating factor (GM-CSF), among other cytokines, in the presence of TGF-ß while cytokine expression in untransduced T cells is being markedly suppressed. Furthermore, T cells expressing GPI-ecto-TßRII constructs have been shown to efficiently capture and inactivate TGF-ß from their environment. These results indicate the potential benefits of GPI-ecto-TßRII expressing cytotoxic T cells (CTLs) in future cell therapies.

Themis controls T cell activation, effector functions, and metabolism of peripheral CD8+ T cells.

Themis is important in regulating positive selection of thymocytes during T cell development, but its role in peripheral T cells is less understood. Here, we investigated T cell activation and its sequelae using a tamoxifen-mediated, acute Themis deletion mouse model. We find that proliferation, effector functions including anti-tumor killing, and up-regulation of energy metabolism are severely compromised. This study reveals the phenomenon of peripheral adaptation to loss of Themis, by demonstrating direct TCR-induced defects after acute deletion of Themis that were not evident in peripheral T cells chronically deprived of Themis in dLck-Cre deletion model. Peripheral adaptation to long-term loss was compared using chronic versus acute tamoxifen-mediated deletion and with the (chronic) dLck-Cre deletion model. We found that upon chronic tamoxifen-mediated Themis deletion, there was modulation in the gene expression profile for both TCR and cytokine signaling pathways. This profile overlapped with (chronic) dLck-Cre deletion model. Hence, we found that peripheral adaptation induced changes to both TCR and cytokine signaling modules. Our data highlight the importance of Themis in the activation of CD8+ T cells.

A phase I study of an adenoviral vector delivering a MUC1/CD40-ligand fusion protein in patients with advanced adenocarcinoma.

Cancer vaccines as immunotherapy for solid tumours are currently in development with promising results. We report a phase 1 study of Ad-sig-hMUC1/ecdCD40L (NCT02140996), an adenoviral-vector vaccine encoding the tumour-associated antigen MUC1 linked to CD40 ligand, in patients with advanced adenocarcinoma. The primary objective of this study is safety and tolerability. We also study the immunome in vaccinated patients as a secondary outcome. This trial, while not designed to determine clinical efficacy, reports an exploratory endpoint of overall response rate. The study meets its pre-specified primary endpoint demonstrating safety and tolerability in a cohort of 21 patients with advanced adenocarcinomas (breast, lung and ovary). The maximal dose of the vaccine is 1 ×1011 viral particles, with no dose limiting toxicities. All drug related adverse events are of low grades, most commonly injection site reactions in 15 (71%) patients. Using exploratory high-dimensional analyses, we find both quantitative and relational changes in the cancer immunome after vaccination. Our data highlights the utility of high-dimensional analyses in understanding and predicting effective immunotherapy, underscoring the importance of immune competency in cancer prognosis.

ZAKα-driven ribotoxic stress response activates the human NLRP1 inflammasome.

Human NLRP1 (NACHT, LRR, and PYD domain-containing protein 1) is an innate immune sensor predominantly expressed in the skin and airway epithelium. Here, we report that human NLRP1 senses the ultraviolet B (UVB)- and toxin-induced ribotoxic stress response (RSR). Biochemically, RSR leads to the direct hyperphosphorylation of a human-specific disordered linker region of NLRP1 (NLRP1DR) by MAP3K20/ZAKα kinase and its downstream effector, p38. Mutating a single ZAKα phosphorylation site in NLRP1DR abrogates UVB- and ribotoxin-driven pyroptosis in human keratinocytes. Moreover, fusing NLRP1DR to CARD8, which is insensitive to RSR by itself, creates a minimal inflammasome sensor for UVB and ribotoxins. These results provide insight into UVB sensing by human skin keratinocytes, identify several ribotoxins as NLRP1 agonists, and establish inflammasome-driven pyroptosis as an integral component of the RSR.

Dendritic cell therapy with CD137L-DC-EBV-VAX in locally recurrent or metastatic nasopharyngeal carcinoma is safe and confers clinical benefit.

INTRODUCTION: Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), and provides a target for a dendritic cell (DC) vaccine. CD137 ligand (CD137L) expressed on antigen presenting cells, costimulates CD137-expressing T cells, and reverse CD137L signaling differentiates monocytes to CD137L-DC, a type of DC, which is more potent than classical DC in stimulating T cells. METHODS: In this phase I study, patients with locally recurrent or metastatic NPC were administered CD137L-DC pulsed with EBV antigens (CD137L-DC-EBV-VAX). RESULTS: Of the 12 patients treated, 9 received full 7 vaccine doses with a mean administered cell count of 23.9 × 106 per dose. Treatment was well tolerated with only 4 cases of grade 1 related adverse events. A partial response was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2-3 years. The mean pre-treatment neutrophil: lymphocyte ratio was 3.4 and a value of less than 3 was associated with prolonged median PFS. Progressors were characterized by a high frequency of naïve T cells but a low frequency of CD8+ effector T cells while patients with a clinical benefit (CB) had a high frequency of memory T cells. Patients with CB had lower plasma EBV DNA levels, and a reduction after vaccination. CONCLUSION: CD137L-DC-EBV-VAX was well tolerated. The use of CD137L-DC-EBV-VAX is demonstrated to be safe. Consistent results were obtained from all 12 patients, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies in patients post effective chemotherapy. PRECIS: The first clinical testing of CD137L-DC, a new type of monocyte-derived DC, finds that CD137L-DC are safe, and that they can induce an immune response against Epstein-Barr virus-associated nasopharyngeal carcinoma that leads to tumor regression or prevents tumor progression.

Systemic inflammation, innate immunity and pathogenesis after Zika virus infection in cynomolgus macaques are modulated by strain-specificity within the Asian lineage.

Zika virus (ZIKV) is an emerging arbovirus with recent global expansion. Historically, ZIKV infections with Asian lineages have been associated with mild disease such as rash and fever. However, recent Asian sub-lineages have caused outbreaks in the South Pacific and Latin America with increased prevalence of neurological disorders in infants and adults. Asian sub-lineage differences may partially explain the range of disease severity observed. However, the effect of Asian sub-lineage differences on pathogenesis remains poorly characterized. Current study conducts a head-to-head comparison of three Asian sub-lineages that are representative of the circulating ancestral mild Asian strain (ZIKV-SG), the 2007 epidemic French Polynesian strain (ZIKV-FP), and the 2013 epidemic Brazil strain (ZIKV-Brazil) in adult Cynomolgus macaques. Animals infected intervenously or subcutaneously with either of the three clinical isolates showed sub-lineage-specific differences in viral pathogenesis, early innate immune responses and systemic inflammation. Despite the lack of neurological symptoms in infected animals, the epidemiologically neurotropic ZIKV sub-lineages (ZIKV-Brazil and/or ZIKV-FP) were associated with more sustained viral replication, higher systemic inflammation (i.e. higher levels of TNFα, MCP-1, IL15 and G-CSF) and greater percentage of CD14+ monocytes and dendritic cells in blood. Multidimensional analysis showed clustering of ZIKV-SG away from ZIKV-Brazil and ZIKV-FP, further confirming sub-lineage differences in the measured parameters. These findings highlight greater systemic inflammation and monocyte recruitment as possible risk factors of adult ZIKV disease observed during the 2007 FP and 2013 Brazil epidemics. Future studies should explore the use of anti-inflammatory therapeutics as early treatment to prevent ZIKV-associated disease in adults.

Effective Killing of Acute Myeloid Leukemia by TIM-3 Targeted Chimeric Antigen Receptor T Cells.

Acute myeloid leukemia (AML) is an aggressive disease with poor outcomes, overwhelmingly due to relapse. Minimal residual disease (MRD), defined as the persistence of leukemic cells after chemotherapy treatment, is thought to be the major cause of relapse. The origins of relapse in AML have been traced to rare therapy-resistant leukemic stem cells (LSCs) that are already present at diagnosis. Effective treatment strategies for long-term remission are lacking, as it has been difficult to eliminate LSCs with conventional therapy. Here, we proposed a new approach based on the chimeric antigen receptor (CAR)-directed T lymphocytes, targeting T-cell immunoglobulin, and mucin domain 3 (TIM-3) to treat MRD in patients with AML. TIM-3 is selected as the target because it is highly expressed on AML blasts and LSCs in most subtypes regardless of the patient's genetic characteristics and treatment course. Moreover, it is absent in the normal hematopoietic stem cells, granulocytes, naïve lymphocytes, and most normal nonhematopoietic tissues. Using a naïve human Fab phage display library, we isolated an anti-human TIM-3 antibody and designed a second-generation anti-TIM-3. Our anti-TIM-3 CAR T cells exhibit potent antileukemic activity against AML cell lines and primary AML blasts, and in the mouse models. More importantly, we demonstrate efficient killing of the primary LSCs directly isolated from the patients. Hence, eradication of the LSCs present in the MRD by anti-TIM-3 CAR T-cell therapy following the first-line treatment may improve the clinical outcomes of patients with AML.

Monocytic Myeloid-Derived Suppressor Cells Underpin Resistance to Adoptive T Cell Therapy in Nasopharyngeal Carcinoma.

Advanced, late-stage Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) is incurable, and its treatment remains a clinical and therapeutic challenge. Results from a phase II clinical trial in advanced NPC patients employing a combined chemotherapy and EBV-specific T cell (EBVST) immunotherapy regimen showed a response rate of 71.4%. Longitudinal analysis of patient samples showed that an increase in EBV DNA plasma concentrations and the peripheral monocyte-to-lymphocyte ratio negatively correlated with overall survival. These parameters were combined into a multivariate analysis to stratify patients according to risk of death. Immunophenotyping at serial time points showed that low-risk individuals displayed significantly decreased amounts of monocytic myeloid-derived suppressor cells postchemotherapy, which subsequently influenced successful cytotoxic T-lymphocyte (CTL) immunotherapy. Examination of the low-risk group, 2 weeks post-EBVST infusion, showed that individuals with a greater overall survival possessed an increased frequency of CD8 central and effector memory T cells, together with higher levels of plasma interferon (IFN)-γ, and cytotoxic lymphocyte-associated transcripts. These results highlight the importance of the rational selection of chemotherapeutic agents and consideration of their impact on both systemic immune responses and downstream cellular immunotherapy outcomes.

Dominant-negative NFKBIA mutation promotes IL-1ß production causing hepatic disease with severe immunodeficiency.

Although IKK-ß has previously been shown as a negative regulator of IL-1ß secretion in mice, this role has not been proven in humans. Genetic studies of NF-κB signaling in humans with inherited diseases of the immune system have not demonstrated the relevance of the NF-κB pathway in suppressing IL-1ß expression. Here, we report an infant with a clinical pathology comprising neutrophil-mediated autoinflammation and recurrent bacterial infections. Whole-exome sequencing revealed a de novo heterozygous missense mutation of NFKBIA, resulting in a L34P IκBα variant that severely repressed NF-κB activation and downstream cytokine production. Paradoxically, IL-1ß secretion was elevated in the patient's stimulated leukocytes, in her induced pluripotent stem cell-derived macrophages, and in murine bone marrow-derived macrophages containing the L34P mutation. The patient's hypersecretion of IL-1ß correlated with activated neutrophilia and liver fibrosis with neutrophil accumulation. Hematopoietic stem cell transplantation reversed neutrophilia, restored a resting state in neutrophils, and normalized IL-1ß release from stimulated leukocytes. Additional therapeutic blockade of IL-1 ameliorated liver damage, while decreasing neutrophil activation and associated IL-1ß secretion. Our studies reveal a previously unrecognized role of human IκBα as an essential regulator of canonical NF-κB signaling in the prevention of neutrophil-dependent autoinflammatory diseases. These findings also highlight the therapeutic potential of IL-1 inhibitors in treating complications arising from systemic NF-κB inhibition.

A multicenter phase II randomized trial of durvalumab (MEDI-4736) versus physician's choice chemotherapy in recurrent ovarian clear cell adenocarcinoma (MOCCA).

BACKGROUND: The optimal treatment of recurrent ovarian clear cell carcinoma remains unknown. There is increasing rationale to support the role of immune checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis in ovarian clear cell carcinoma. PRIMARY OBJECTIVE: To evaluate the efficacy of durvalumab (MEDI-4736) compared with standard chemotherapy in patients with recurrent ovarian clear cell carcinoma. STUDY HYPOTHESIS: Patients with recurrent ovarian clear cell carcinoma treated with durvalumab will have improved progression-free survival compared with those treated with chemotherapy of physician's choice. TRIAL DESIGN: The MOCCA study is a multicenter, open-label, randomized phase II trial in patients with recurrent ovarian clear cell carcinoma, which recruited from eight sites across Gynecologic Cancer Group Singapore (GCGS), Korean Gynecologic-Oncology Group (KGOG), and Australia New Zealand Gynecological Oncology Group (ANZGOG). Enrolled patients were randomized in a 2:1 ratio to receive durvalumab or physician's choice of chemotherapy until disease progression, intolerable toxicity, or withdrawal of patient consent. MAJOR INCLUSION/EXCLUSION CRITERIA: Eligible patients required histologically documented diagnosis of recurrent ovarian clear cell carcinoma, as evidenced by WT1 negativity. All patients must have been of Eastern Cooperative Oncology Group (ECOG) performance status 2 or better, and have had previous treatment with, and progressed or recurred after prior platinum-based chemotherapy. No more than four prior lines of treatment were allowed and prior immune checkpoint inhibitor treatment was not permitted. PRIMARY ENDPOINTS: The primary endpoint was the median progression-free survival following treatment with durvalumab, compared with physician's choice of chemotherapy. Progression-free survival was defined as the time from the first day of treatment to the first observation of disease progression, or death due to any cause, or last follow-up. SAMPLE SIZE: The target sample size was 46 patients. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Accrual has been completed and results are expected to be presented by mid-2021. TRIAL REGISTRATION: Clinicaltrials.gov: NCT03405454.

IRF-7 Mediates Type I IFN Responses in Endotoxin-Challenged Mice.

IRF-7 mediates robust production of type I IFN via MyD88 of the TLR9 pathway in plasmacytoid dendritic cells (pDCs). Previous in vitro studies using bone marrow-derived dendritic cells lacking either Irf7 or Irf3 have demonstrated that only IRF-3 is required for IFN-ß production in the TLR4 pathway. Here, we show that IRF-7 is essential for both type I IFN induction and IL-1ß responses via TLR4 in mice. Mice lacking Irf7 were defective in production of both IFN-ß and IL-1ß, an IFN-ß-induced pro-inflammatory cytokine, after LPS challenge. IFN-ß production in response to LPS was impaired in IRF-7-deficient macrophages, but not dendritic cells. Unlike pDCs, IRF-7 is activated by the TRIF-, but not MyD88-, dependent pathway via TBK-1 in macrophages after LPS stimulation. Like pDCs, resting macrophages constitutively expressed IRF-7 protein. This basal IRF-7 protein was completely abolished in either Ifnar1-/- or Stat1-/- macrophages, which corresponded with the loss of LPS-stimulated IFN-ß induction in these macrophages. These findings demonstrate that macrophage IRF-7 is critical for LPS-induced type I IFN responses, which in turn facilitate IL-1ß production in mice.

Personal level exposure and hazard potential of particulate matter during haze and non-haze periods in Singapore.

Severe haze episodes originating from biomass burning are common in Southeast Asia. However, there is a paucity of data on the personal exposure and characteristics of Particulate Matter (PM) present in ambient air during haze and non-haze periods. Aims of this study were to monitor 24 h ambulatory exposure to PM among school children in Singapore; characterize haze and non-haze PM for their physicochemical properties, cytotoxicity and inflammatory potential, using bronchial epithelial cell culture model (BEAS-2B). Forty-six children had ambulatory PM exposure monitored using portable Aethalometer and their hourly activity recorded. The mean (±SE) PM exposure on a typical school day was 3343 (±174.4) ng/m3/min. Higher PM exposure was observed during haze periods and during commuting to and from the school. Characterization of PM collected showed a drastic increase in the proportion of ultrafine particle (UFP) in haze PM. These PM fraction showed higher level of sulphur, potassium and trace metals in comparison to those collected during non-haze periods. Dose dependent increases in abiotic reactive oxygen species generation, activation of NF-κB and cytotoxicity were observed for both haze and non-haze PM. Generally, haze PM induced significantly higher release of IL-6, IL-8 and TNFα by BEAS-2B cells in comparison to non-haze PM. In summary, this study provides experimental evidence for higher PM exposure during haze period which has the potential to elicit oxidative stress and pro-inflammatory cytokine release from airway epithelial cells.

TLR7 Protein Expression in Mild and Severe Lupus-Prone Models Is Regulated in a Leukocyte, Genetic, and IRAK4 Dependent Manner.

The global increase in autoimmunity, together with the emerging autoimmune-related side effects of cancer immunotherapy, have furthered a need for understanding of immune tolerance and activation. Systemic lupus erythematosus (SLE) is the archetypical autoimmune disease, affecting multiple organs, and tissues. Studying SLE creates knowledge relevant not just for autoimmunity, but the immune system in general. Murine models and patient studies have provided increasing evidence for the innate immune toll like receptor-7 (TLR7) in disease initiation and progression. Here, we demonstrated that the kinase activity of the TLR7-downstream signaling molecule, interleukin-1 receptor associated kinase 4 (IRAK4), is essential for mild and severe autoimmune traits of the Sle1 and Sle1-TLR7 transgenic (Sle1Tg7) murine models, respectively. Elimination of IRAK4 signaling prevented all pathological traits associated with murine lupus, including splenomegaly with leukocyte expansion, detectable circulating antinuclear antibodies and glomerulonephritis, in both Sle1 and Sle1Tg7 mice. The expansion of germinal center B cells and increased effector memory T cell phenotypes that are typical of lupus-prone strains, were also prevented with IRAK4 kinase elimination. Analysis of renal leukocyte infiltrates confirmed our earlier findings of an expanded conventional dendritic cell (cDC) within the kidneys of nephritic mice, and this was prevented with IRAK4 kinase elimination. Analysis of TLR7 at the protein level revealed that the expression in immune cells is dependent on the TLR7-transgene itself and/or autoimmune disease factors in a cell-specific manner. Increased TLR7 protein expression in renal macrophages and cDCs correlated with disease parameters such as blood urea nitrogen (BUN) levels and the frequency of leukocytes infiltrating the kidney. These findings suggest that controlling the level of TLR7 or downstream signaling within myeloid populations may prevent chronic inflammation and severe nephritis.

Enhancing Antigen Cross-Presentation in Human Monocyte-Derived Dendritic Cells by Recruiting the Intracellular Fc Receptor TRIM21.

Suboptimal immune responses to pathogens contribute to chronic infections. One way to improve immune responses is to boost Ag presentation. In this study, we investigate the potential of the tripartite motif-containing 21 (TRIM21) pathway. TRIM21 is a ubiquitously expressed cytosolic protein that recognizes the Fc region of Abs. When Abs that are bound to pathogens enter the cell as immune complexes, binding of TRIM21 to Fc initiates downstream inflammatory signaling and targets the immune complexes for proteasomal degradation. In APCs, peptides generated by proteasomes are loaded onto MHC class I molecules to stimulate CD8 T cell responses, which are crucial for effective immunity to pathogens. We hypothesized that increasing the affinity between immune complexes and TRIM21 might markedly improve CD8 T cell responses to Ags processed by the TRIM21 pathway. Using phage display technology, we engineered the human IgG1 Fc to increase its affinity for TRIM21 by 100-fold. Adenovirus immune complexes with the engineered Fc induced greater maturation of human dendritic cells (DC) than immune complexes with unmodified Fc and stimulated increased Ag-specific CD8 T cell proliferation and IFN-γ release in cocultures of DC-PBMC. Thus, by increasing the affinity between Fc and TRIM21, Ags from immune complexes undergo enhanced cross-presentation on DC, leading to greater CD8 T cell responses. Our study reveals an approach that could potentially be used in vaccines to increase cytotoxic T cell responses against Ags that are targeted or delivered by Fc-modified Abs.

Distinct "Immunoallertypes" of Disease and High Frequencies of Sensitization in Non-Cystic Fibrosis Bronchiectasis.

RATIONALE: Allergic sensitization is associated with poor clinical outcomes in asthma, chronic obstructive pulmonary disease, and cystic fibrosis; however, its presence, frequency, and clinical significance in non-cystic fibrosis bronchiectasis remain unclear. OBJECTIVES: To determine the frequency and geographic variability that exists in a sensitization pattern to common and specific allergens, including house dust mite and fungi, and to correlate such patterns to airway immune-inflammatory status and clinical outcomes in bronchiectasis. METHODS: Patients with bronchiectasis were recruited in Asia (Singapore and Malaysia) and the United Kingdom (Scotland) (n = 238), forming the Cohort of Asian and Matched European Bronchiectasis, which matched recruited patients on age, sex, and bronchiectasis severity. Specific IgE response against a range of common allergens was determined, combined with airway immune-inflammatory status and correlated to clinical outcomes. Clinically relevant patient clusters, based on sensitization pattern and airway immune profiles ("immunoallertypes"), were determined. MEASUREMENTS AND MAIN RESULTS: A high frequency of sensitization to multiple allergens was detected in bronchiectasis, exceeding that in a comparator cohort with allergic rhinitis (n = 149). Sensitization was associated with poor clinical outcomes, including decreased pulmonary function and more severe disease. "Sensitized bronchiectasis" was classified into two immunoallertypes: one fungal driven and proinflammatory, the other house dust mite driven and chemokine dominant, with the former demonstrating poorer clinical outcome. CONCLUSIONS: Allergic sensitization occurs at high frequency in patients with bronchiectasis recruited from different global centers. Improving endophenotyping of sensitized bronchiectasis, a clinically significant state, and a "treatable trait" permits therapeutic intervention in appropriate patients, and may allow improved stratification in future bronchiectasis research and clinical trials.

Human DPP9 represses NLRP1 inflammasome and protects against autoinflammatory diseases via both peptidase activity and FIIND domain binding.

The inflammasome is a critical molecular complex that activates interleukin-1 driven inflammation in response to pathogen- and danger-associated signals. Germline mutations in the inflammasome sensor NLRP1 cause Mendelian systemic autoimmunity and skin cancer susceptibility, but its endogenous regulation remains less understood. Here we use a proteomics screen to uncover dipeptidyl dipeptidase DPP9 as a novel interacting partner with human NLRP1 and a related inflammasome regulator, CARD8. DPP9 functions as an endogenous inhibitor of NLRP1 inflammasome in diverse primary cell types from human and mice. DPP8/9 inhibition via small molecule drugs and CRISPR/Cas9-mediated genetic deletion specifically activate the human NLRP1 inflammasome, leading to ASC speck formation, pyroptotic cell death, and secretion of cleaved interleukin-1ß. Mechanistically, DPP9 interacts with a unique autoproteolytic domain (Function to Find Domain (FIIND)) found in NLRP1 and CARD8. This scaffolding function of DPP9 and its catalytic activity act synergistically to maintain NLRP1 in its inactive state and repress downstream inflammasome activation. We further identified a single patient-derived germline missense mutation in the NLRP1 FIIND domain that abrogates DPP9 binding, leading to inflammasome hyperactivation seen in the Mendelian autoinflammatory disease Autoinflammation with Arthritis and Dyskeratosis. These results unite recent findings on the regulation of murine Nlrp1b by Dpp8/9 and uncover a new regulatory mechanism for the NLRP1 inflammasome in primary human cells. Our results further suggest that DPP9 could be a multifunctional inflammasome regulator involved in human autoinflammatory diseases.

Chromosomal instability-induced senescence potentiates cell non-autonomous tumourigenic effects.

Chromosomal instability (CIN), a high rate of chromosome loss or gain, is often associated with poor prognosis and drug resistance in cancers. Aneuploid, including near-polyploid, cells contain an abnormal number of chromosomes and exhibit CIN. The post-mitotic cell fates following generation of different degrees of chromosome mis-segregation and aneuploidy are unclear. Here we used aneuploidy inducers, nocodazole and reversine, to create different levels of aneuploidy. A higher extent of aneuploid and near-polyploid cells in a given population led to senescence. This was in contrast to cells with relatively lower levels of abnormal ploidy that continued to proliferate. Our findings revealed that senescence was accompanied by DNA damage and robust p53 activation. These senescent cells acquired the senescence-associated secretory phenotype (SASP). Depletion of p53 reduced the number of senescent cells with concomitant increase in cells undergoing DNA replication. Characterisation of these SASP factors demonstrated that they conferred paracrine pro-tumourigenic effects such as invasion, migration and angiogenesis both in vitro and in vivo. Finally, a correlation between increased aneuploidy and senescence was observed at the invasive front in breast carcinomas. Our findings demonstrate functional non-equivalence of discernable aneuploidies on tumourigenesis and suggest a cell non-autonomous mechanism by which aneuploidy-induced senescent cells and SASP can affect the tumour microenvironment to promote tumour progression.

Autophagy Governs Protumorigenic Effects of Mitotic Slippage-induced Senescence.

The most commonly utilized class of chemotherapeutic agents administered as a first-line therapy are antimitotic drugs; however, their clinical success is often impeded by chemoresistance and disease relapse. Hence, a better understanding of the cellular pathways underlying escape from cell death is critical. Mitotic slippage describes the cellular process where cells exit antimitotic drug-enforced mitotic arrest and "slip" into interphase without proper chromosome segregation and cytokinesis. The current report explores the cell fate consequence following mitotic slippage and assesses a major outcome following treatment with many chemotherapies, therapy-induced senescence. It was found that cells postslippage entered senescence and could impart the senescence-associated secretory phenotype (SASP). SASP factor production elicited paracrine protumorigenic effects, such as migration, invasion, and vascularization. Both senescence and SASP factor development were found to be dependent on autophagy. Autophagy induction during mitotic slippage involved the autophagy activator AMPK and endoplasmic reticulum stress response protein PERK. Pharmacologic inhibition of autophagy or silencing of autophagy-related ATG5 led to a bypass of G1 arrest senescence, reduced SASP-associated paracrine tumorigenic effects, and increased DNA damage after S-phase entry with a concomitant increase in apoptosis. Consistent with this, the autophagy inhibitor chloroquine and microtubule-stabilizing drug paclitaxel synergistically inhibited tumor growth in mice. Sensitivity to this combinatorial treatment was dependent on p53 status, an important factor to consider before treatment.Implications: Clinical regimens targeting senescence and SASP could provide a potential effective combinatorial strategy with antimitotic drugs. Mol Cancer Res; 16(11); 1625-40. ©2018 AACR.