Immunogenic cell death and cross-priming are reaching the clinical immunotherapy arena.
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
BACKGROUND: Lung adenocarcinoma (LUAD) is one of the most common malignant diseases worldwide. This study aimed to construct an immunogenic cell death (ICD)-related long non-coding RNA (lncRNA) signature to effectively predict the prognosis of LUAD. METHODS: The RNA-sequencing and clinical data of LUAD were downloaded from The Cancer Genome Atlas (TCGA). Least absolute shrinkage and selection operator (LASSO) and stepwise multivariate Cox proportional hazard regression analysis were utilized to construct lncRNA signature. Then, the reliability of the signature was evaluated in the training, validation and whole cohorts. The differences in the immune landscape and drug sensitivity between the low- and high-risk groups were analyzed. Finally, the expression level of the selected ICD-related lncRNAs in LUAD cell lines via reverse transcription quantitative PCR (RT-qPCR). CCK-8 and transwell assays were performed to study biological function of AC245014.3. RESULTS: A signature consisting of 5 ICD-related lncRNAs was constructed. Kaplan Meier (K-M) survival analysis showed shorter overall survival (OS) in high-risk group. The receiver operating characteristic (ROC) curves and Multivariate Cox regression analysis showed the signature was good predictive and independent prognostic factor in LUAD. Moreover, the high-risk group had a lower level of antitumor immunity and was less sensitive to some chemotherapeutics and targeted drugs. Finally, the expression level of selected ICD-related lncRNAs was validated in LUAD cell lines by RT-qPCR. Knockdown of AC245014.3 significantly suppressed LUAD proliferation, migration and invasion. CONCLUSIONS: In this study, an ICD-related lncRNA signature was constructed, which could accurately predict the prognosis of LUAD patients and guide clinical treatment.
Heat shock protein expression and release is closely associated with immunogenic forms of cell death. We show that activation of the stress response within tumor cells during cell death, using an engineered form of the heat shock transcription factor, leads to an immunogenic death. Cells dying through 'stressful death' show decreased phagocytosis by macrophages in vitro. Moreover, cells expressing heat shock proteins during cell death are significantly more protective against subsequent tumor challenge. These data demonstrate the utility of activating cellular stress programs over the course of cytotoxic therapies to enhance immune responses to dying cells.
Loss-of-function mutations in Kelch-like ECH-associated protein 1 (KEAP1) frequently occur in lung adenocarcinoma and are associated with poor prognosis and limited benefit from immunotherapy. However, the mechanisms linking KEAP1 deficiency to immune evasion remain elusive. We combined clinical data analysis, in vivo tumor models, and in vitro co-culture systems to investigate how KEAP1 deficiency shapes dendritic cell (DC) biology and response to PD-1 blockade. Ferroptosis induction assays, damage-associated molecular patterns (DAMPs) quantification, cytokine profiling, and mechanistic interrogation of the FSP1-CoQ10 axis were performed to delineate pathways.KEAP1 mutations correlated with poor response to PD-1 blockade and reduced DC infiltration. In mice, KEAP1-deficient tumors exhibited accelerated growth and reduced DC and CD8+ T-cell infiltration, consistent with an immune-cold phenotype. Mechanistically, KEAP1 loss impaired DC function in vitro, as evidenced by reduced maturation, phagocytosis, and naïve CD8+ T-cell priming capacity. This defect was linked to two mechanisms. First, KEAP1-deficient tumor cells resisted ferroptosis and failed to release immunogenic DAMPs, including extracellular ATP, HMGB1, and calreticulin. Second, KEAP1 deficiency reprogrammed the cytokine secretion profile, with downregulation of CCL2, IL-6, CXCL1, and CXCL2, thereby diminishing DC recruitment and inflammatory signaling. Notably, inhibition of the FSP1-CoQ10 antioxidant axis restored ferroptosis-associated immunogenic cell death. Our study identifies KEAP1 deficiency as a driver of immune-cold tumor microenvironments and resistance to PD-1 blockade, acting through impaired ferroptosis-induced immunogenic cell death and disrupted DC function. Genetic FSP1 deletion restored ferroptosis-associated immunogenicity and DC activation in KEAP1-deficient cells, supporting FSP1 as a potential therapeutic target for further in vivo evaluation.
Systemic anticancer chemotherapy is immunosuppressive and mostly induces nonimmunogenic tumor cell death. Here, we show that even in the absence of any adjuvant, tumor cells dying in response to anthracyclins can elicit an effective antitumor immune response that suppresses the growth of inoculated tumors or leads to the regression of established neoplasia. Although both antracyclins and mitomycin C induced apoptosis with caspase activation, only anthracyclin-induced immunogenic cell death was immunogenic. Caspase inhibition by Z-VAD-fmk or transfection with the baculovirus inhibitor p35 did not inhibit doxorubicin (DX)-induced cell death, yet suppressed the immunogenicity of dying tumor cells in several rodent models of neoplasia. Depletion of dendritic cells (DCs) or CD8+T cells abolished the immune response against DX-treated apoptotic tumor cells in vivo. Caspase inhibition suppressed the capacity of DX-killed cells to be phagocytosed by DCs, yet had no effect on their capacity to elicit DC maturation. Freshly excised tumors became immunogenic upon DX treatment in vitro, and intratumoral inoculation of DX could trigger the regression of established tumors in immunocompetent mice. These results delineate a procedure for the generation of cancer vaccines and the stimulation of anti-neoplastic immune responses in vivo.
Explore the source record for details and available documents.
Anthracyclin-treated tumor cells are particularly effective in eliciting an anticancer immune response, whereas other DNA-damaging agents such as etoposide and mitomycin C do not induce immunogenic cell death. Here we show that anthracyclins induce the rapid, preapoptotic translocation of calreticulin (CRT) to the cell surface. Blockade or knockdown of CRT suppressed the phagocytosis of anthracyclin-treated tumor cells by dendritic cells and abolished their immunogenicity in mice. The anthracyclin-induced CRT translocation was mimicked by inhibition of the protein phosphatase 1/GADD34 complex. Administration of recombinant CRT or inhibitors of protein phosphatase 1/GADD34 restored the immunogenicity of cell death elicited by etoposide and mitomycin C, and enhanced their antitumor effects in vivo. These data identify CRT as a key feature determining anticancer immune responses and delineate a possible strategy for immunogenic chemotherapy.
BACKGROUND: Ovarian cancer (OC) remains the deadliest gynecologic malignancy, largely due to its immunosuppressive tumor microenvironment (TME) and resistance to therapy. Necroptosis, a regulated lytic cell death pathway mediated by the RIPK1-RIPK3-MLKL axis, can trigger immunogenic cell death, but its specific role in shaping the OC immune landscape and its clinical translation potential are posorly understood. METHODS: We employed multi-omics analysis (transcriptomics, genomics, clinical data) from TCGA-OV (n = 380), ICGC OV-AU, and IMvigor210 cohorts, combined with rigorous in vitro functional validation using OC cell lines (SKOV3, HEY), macrophages (THP-1 derived), and T cells (Jurkat). Computational immunology approaches (ESTIMATE, CIBERSORT, ssGSEA) quantified immune infiltration. We identified MLKL-associated immune genes, performed survival analysis (Kaplan-Meier, Cox regression), and constructed a necroptosis-immune signature (NecropImmScore) using consensus clustering and PCA of 102 prognostic genes. Drug sensitivity was predicted via pRRophetic and CellMiner. RESULTS: MLKL emerged as a protective prognostic biomarker (p = 0.018), significantly correlated with enhanced immune infiltration (ImmuneScore, StromalScore, ESTIMATEScore; p < 2.22e-16), M1 macrophage polarization (p = 0.006), activated CD4 + T cells (p = 0.003), and elevated immune checkpoint expression (PD-L1, CTLA4, LAG3, TIGIT). In vitro, MLKL overexpression in OC cells promoted M1 polarization (p < 0.05), activated Jurkat T cells (upregulated CCR4/5/7/9, CD69, CD3D/E, GZMB; p < 0.05), and induced key chemokines (CXCL9/10/11/13) critical for immune cell recruitment. Integration of MLKL-related and immune-related DEGs (n = 632) revealed enrichment in T-cell activation, chemokine signaling, and antigen presentation pathways (FDR < 0.05). Consensus clustering based on 102 survival-associated genes defined three molecular subtypes (Clusters A-C) with divergent survival (p = 0.019), necroptosis activity, and immune infiltration (Cluster C: best prognosis, highest MLKL/ImmuneScore). The derived NecropImmScore robustly stratified patients: high-score correlated with superior overall survival (TCGA: p < 0.001; ICGC: p = 0.014), inflamed TME phenotype, elevated checkpoint expression, and improved response to anti-PD-L1 in IMvigor210. Critically, high NecropImmScore predicted higher BRCA1 mutation frequency (AUC = 0.802), synergy with BRCA1 status for prognosis, higher homologous recombination deficiency (HRD) score, sensitivity to cisplatin (p = 0.014), paclitaxel (p = 0.016), gemcitabine (p = 0.017), and provided superior prognostic stratification when combined with TMB and HRD score (p < 0.001). CONCLUSION: This study establishes MLKL as a master regulator of anti-tumor immunity in OC, driving chemokine-mediated immune cell recruitment and TME reprogramming. The novel NecropImmScore is a multifaceted biomarker that effectively predicts prognosis, immunotherapy response, BRCA1 deficiency, and chemosensitivity, offering significant potential for guiding precision therapeutic strategies in OC.
Necrotic cell death yields the release of cellular components that can function in the initiation of cellular immune responses. Given the established capacity of the endoplasmic reticulum chaperone GRP94 (gp96) to elicit CD8(+) T cell activation, we have investigated the cellular fate and antigenicity of GRP94 in differing scenarios of cell death. Virally induced cell death or mechanical cell death, elicited by freeze/thaw treatment of cell suspensions, yielded GRP94 release into the extracellular space; apoptotic cell death occurring in response to serum deprivation did not elicit GRP94 release. To assess the antigenicity of GRP94 released following virally induced cell death (lethal infection of cells with rVV ES-OVA(Met258-265), a recombinant, ovalbumin epitope-expressing vaccinia virus) or mechanical cell death (freeze/thaw of ovalbumin-expressing cells), tissue culture supernatant fractions were pulsed onto antigen-presenting cells, and antigen re-presentation was assayed as activation of an ovalbumin-specific T cell hybridoma. For both cell death scenarios, released GRP94 elicited a dose-dependent, ovalbumin-specific, hybridoma activation. In contrast, calreticulin derived from rVV ES-OVA(Met258-265)-infected cell extracts did not stimulate B3Z activity. These data identify GRP94 as an antigenic component released upon pathological, but not apoptotic, cell death and provide an assay system for the identification of cellular components of related activity.
Rheumatoid arthritis (RA) is a life-long autoimmune disease caused by the confluence of genetic and environmental variables that lead to loss of self-tolerance and persistent joint inflammation. RA occurs at the highest incidence in individuals >65 years old, implicating the aging process in disease susceptibility. Transformative approaches in molecular immunology and in functional genomics have paved the way for pathway paradigms underlying the replacement of immune homeostasis with autodestructive immunity in affected patients, including the process of immune aging. Patients with RA have a signature of premature immune aging, best understood for CD4+ T cells, which function as pathogenic effectors in this HLA class II-associated disease. Premature immune aging is present in healthy HLA-DRB1*04+ individuals, placing accelerated immune aging before joint inflammation. Aging-related molecular abnormalities directly implicated in turning RA CD4+ T cells into proinflammatory effector cells are linked to malfunction of subcellular organelles, such as mitochondria, lysosomes, lipid droplets, and the endoplasmic reticulum. Resulting changes in T cell behavior include cellular hypermobility, tissue invasiveness, unopposed mammalian target of rapamycin complex (mTORC)1 activation, excessive release of tumor necrosis factor, lysosomal failure, clonal expansion, and immunogenic cell death. Aged and metabolically reprogrammed T cells in patients with RA are accompanied by age-associated B cells, which specialize in autoantibody production. Clonal hematopoiesis drives myeloid cell aging by producing aged monocytes and hypermetabolic macrophages, which sustain the process of inflammaging. Here, we synthesize insights into the relationship of RA risk and immune aging and discuss mechanisms through which immune aging can cause autoimmunity.
Cancer immunotherapy has reshaped oncology, largely through immune checkpoint inhibitors that release the brakes on tumor-reactive T cells. Yet the benefit remains uneven, and that unevenness traces back to a few basic biological limits. Checkpoint blockade amplifies immunity that is already present; it does not create tumor specificity de novo. Poor Ag quality, defective Ag presentation, a suppressive microenvironment, and epigenetically fixed T-cell exhaustion together set a ceiling on what checkpoint release can achieve. Next-generation strategies try to move past these limits by reorganizing immunotherapy around the functional layers of the immune response. Cancer vaccines define tumor-specific neoantigens and expand the responses against them. Ab-based approaches tune inhibitory signaling, draw immune cells toward the tumor, and trigger immunogenic cell death. Cellular therapies-chimeric Ag receptor T cell, TCR-engineered T cells, and tumor-infiltrating lymphocytes (TILs)-boost effector potency, with TIL therapy notable for preserving tumor-reactive repertoires shaped in vivo. Rather than rivals, these modalities are best seen as complementary layers-Ag definition, immune priming, effector optimization, and microenvironmental conditioning-to be combined in a programmable way. As genomic profiling, immunopeptidomics, and high-dimensional immune monitoring mature, the field is shifting from checkpoint-centered release toward precision immunoengineering, in which tumor-specific immunity is deliberately designed, aligned, and sustained.
Here we discuss how the mechanisms by which tumor cells are killed in vivo by gene transfer affects their immunogenicity. Our own work has shown that necrotic cell death induces immunological activation signals which recruit, load, activate and mature appropriate subsets of antigen-presenting cells. In contrast, for apoptotic cell death to be immunogenic, signals additional to cell death alone must be provided within the milieu of the dying tumor. Our conclusion is that the immunogenicity of tumor killing is determined by a combination of factors, including the mechanism of killing, the levels of cell death, the local environment that exists within the dying tumor and, as a result, the nature of the immune/scavenger cells which are present at the time of antigen release. Knowledge of how these factors can influence the immune system and lead to the breaking of tolerance to tumor-associated antigens, can potentially be exploited in the design of effective immunotherapies for cancer using gene transfer.
The mechanisms by which the immune system distinguishes normal developmental cell death from pathological immunogenic cell killing are central to effective cancer immunotherapy. Using HSVtk suicide gene therapy, we showed that macrophages can distinguish between tumor cells dying through classical apoptosis and tumor cells engineered to die through nonapoptotic mechanisms, resulting in secretion of either immunosuppressive cytokines (interleukin 10 and transforming growth factor beta) or inflammatory cytokines (tumor necrosis factor alpha or interleukin 1beta), respectively. Additionally heat shock protein 70 acts as one component of a bimodal alarm signal that activates macrophages in the presence of stressful, immunogenic tumor cell killing. These differential responses of macrophages can also be used to vaccinate mice against tumor challenge, using adoptive transfer, as well as to cure mice of established tumors.
Activation-induced cell death (AICD) of mature T cells plays an important role in the control of immune homeostasis and peripheral tolerance. TNFRs and Fas have been implicated in the induction of AICD. However, these molecules were shown to be dispensable, at least in some experimental systems, for downsizing of Ag-induced T cell expansions and development of tolerance in vivo. The conditions of T cell activation leading to T cell deletion in a death receptor-independent manner are not well characterized. Here we show that human CTLs die through a death receptor-independent apoptotic program upon triggering with a partially agonistic peptide ligand. This apoptotic process exhibits some features of T cell death due to lymphokine deprivation and is blocked by exogenous IL-2. Our data demonstrate that engagement of TCR by MHC-peptide complexes can trigger diverse apoptotic programs of AICD and that the choice between these programs is determined by the agonistic potency of MHC-peptide ligand.
The heavy metal mercury elicits a genetically restricted autoantibody response in mice that targets the nucleolar autoantigen fibrillarin. HgCl2-induced cell death of macrophages resulted in the proteolytic cleavage of fibrillarin. A prominent feature of mercury-induced cell death was the generation of a 19-kDa fragment of fibrillarin that was not found following apoptotic or nonapoptotic cell death induced by stimuli other than mercury. Proteolysis of fibrillarin lacking cysteines, and therefore unable to bind mercury, also produced the 19-kDa fragment, suggesting that a mercury-fibrillarin interaction was not necessary for the unique cleavage pattern of this self-Ag. In contrast to immunization with full-length fibrillarin, the 19-kDa fragment produced anti-fibrillarin Abs with some of the properties of the HgCl2-induced anti-fibrillarin response. We propose that cell death following exposure to an autoimmunity-inducing xenobiotic can lead to the generation of novel protein fragments that may serve as sources of antigenic determinants for self-reactive T lymphocytes.
REGb cell line, a highly immunogenic tumor cell variant isolated from a rat colon cancer, yields regressive tumors when injected into syngeneic hosts. We previously demonstrated that REGb tumor immunogenicity was related to the capacity of releasing dead cells in vivo. Also, in vitro, REGb cell monolayers release dead cells, especially when cultured in serum-free medium. In the current study, we show that the release of dead cells results from an atypical death process associating features of necrosis and apoptosis. In spite of features considered as hallmarks of caspase-dependent apoptosis, including chromatin fragmentation and DNA oligonucleosomal cleavage, caspases are not activated and caspase inhibitors are ineffective to prevent REGb cell death. In contrast with a number of other types of cell death, the spontaneous death of REGb cells in culture depends on de novo protein synthesis as this death is blocked by low doses of the mRNA translation inhibitor cycloheximide. This unusual mode of cell death that associates necrotic and apoptotic features could provide optimal conditions for triggering a specific immune response.
Several clinical trials of prostate cancer gene therapy are underway. The therapeutic genes being evaluated by these and other, forthcoming, trials include immunogenes, cell death-inducing genes, antioncogenes, and tumor suppressor genes. Constraints of current gene transfer vectors limit, to local-regional targeting, those gene therapy strategies that do not rely on an intervening immune response. Preclinical models predict modest, if any, therapeutic effects with current forms of prostate cancer gene therapy. Using biological surrogate endpoints and applying further preclinical advances will allow clinical prostate cancer gene therapy to attain its full potential.
Recent studies have demonstrated that circulating antibodies against malondialdehyde-acetaldehyde (MAA)-haptenated proteins are significantly increased in patients with alcohol-induced cirrhosis and hepatitis and correlate with the severity of liver damage. Additionally, when proteins are haptenated with MAA, they become highly immunogenic in vivo in the absence of adjuvants. However, the mechanism(s) of this immunogenicity are currently unknown. Initial in vitro studies on the effects of MAA-modified proteins on cells demonstrated an increase in cell death at concentrations that were cell type specific and time-dependent. Since immunogenicity due to cell death has been described, we investigated the mechanism(s) by which cell death was occurring. Assessment of cell death in splenocytes after 1 h found significant levels of apoptosis as compared to controls. After 5 h, a significant and dose-dependent necrosis occurred in which cells were exposed to >62.5 microg/ml (43.1 mM) MAA-haptenated protein. After 24 h, exposure to >31.3 microg/ml (21.6 mM) MAA-haptenated protein resulted in significant levels of necrosis, although DNA laddering studies found apoptosis was occurring as well. Morphological changes in the cells were observed by light microscopy that correlated with a "low" forward scatter population by flow cytometry. Since necrosis has been implicated in enhancing both primary and secondary immune responses, and necrosis was predominantly occurring in response to MAA-haptenated proteins, a possible mechanism by which the immunogenicity of MAA modification of proteins in vivo may occur is suggested. Specifically, MAA modification of self proteins may result in the death of various cell types, most likely those in the liver. These necrotic materials may induce anti-MAA antibodies and other auto antibodies, whose levels may then correlate with the severity of ALD.