RESUMO
Macrophages and conventional dendritic cells (cDCs) are distributed throughout the body, maintaining tissue homeostasis and tolerance to self and orchestrating innate and adaptive immunity against infection and cancer. As they complement each other, it is important to understand how they cooperate and the mechanisms that integrate their functions. Both are exposed to commensal microbes, pathogens, and other environmental challenges that differ widely among anatomical locations and over time. To adjust to these varying conditions, macrophages and cDCs acquire spatiotemporal adaptations (STAs) at different stages of their life cycle that determine how they respond to infection. The STAs acquired in response to previous infections can result in increased responsiveness to infection, termed training, or in reduced responses, termed paralysis, which in extreme cases can cause immunosuppression. Understanding the developmental stage and location where macrophages and cDCs acquire their STAs, and the molecular and cellular players involved in their induction, may afford opportunities to harness their beneficial outcomes and avoid or reverse their deleterious effects. Here we review our current understanding of macrophage and cDC development, life cycle, function, and STA acquisition before, during, and after infection.We propose a unified framework to explain how these two cell types adjust their activities to changing conditions over space and time to coordinate their immunosurveillance functions.
Assuntos
Imunidade Adaptativa , Células Dendríticas , Animais , Diferenciação Celular , Humanos , Tolerância Imunológica , MacrófagosRESUMO
Breast cancer is a heterogeneous disease. Tumor cells and associated healthy cells form ecosystems that determine disease progression and response to therapy. To characterize features of breast cancer ecosystems and their associations with clinical data, we analyzed 144 human breast tumor and 50 non-tumor tissue samples using mass cytometry. The expression of 73 proteins in 26 million cells was evaluated using tumor and immune cell-centric antibody panels. Tumors displayed individuality in tumor cell composition, including phenotypic abnormalities and phenotype dominance. Relationship analyses between tumor and immune cells revealed characteristics of ecosystems related to immunosuppression and poor prognosis. High frequencies of PD-L1+ tumor-associated macrophages and exhausted T cells were found in high-grade ER+ and ER- tumors. This large-scale, single-cell atlas deepens our understanding of breast tumor ecosystems and suggests that ecosystem-based patient classification will facilitate identification of individuals for precision medicine approaches targeting the tumor and its immunoenvironment.
Assuntos
Neoplasias da Mama , Tolerância Imunológica , Linfócitos do Interstício Tumoral , Macrófagos , Microambiente Tumoral/imunologia , Antígeno B7-H1/imunologia , Neoplasias da Mama/imunologia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Intervalo Livre de Doença , Feminino , Humanos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/patologia , Macrófagos/imunologia , Macrófagos/patologia , Proteínas de Neoplasias/imunologia , Taxa de SobrevidaRESUMO
Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in non-small cell lung cancer (NSCLC). Higher expression of JAG2 in NSCLC negatively correlated with survival. In NSCLC pre-clinical models, deletion of Jag2, but not Jag1, in cancer cells attenuated tumor growth and activated protective anti-tumor T cell responses. Jag2-/- lung tumors exhibited higher frequencies of macrophages that expressed immunostimulatory mediators and triggered T cell-dependent anti-tumor immunity. Mechanistically, Jag2 ablation promoted Nr4a-mediated induction of Notch ligands DLL1/4 on cancer cells. DLL1/4-initiated Notch1/2 signaling in macrophages induced the expression of transcription factor IRF4 and macrophage immunostimulatory functionality. IRF4 expression was required for the anti-tumor effects of Jag2 deletion in lung tumors. Antibody targeting of Jagged2 inhibited tumor growth and activated IRF4-driven macrophage-mediated anti-tumor immunity. Thus, Jagged2 orchestrates immunosuppressive systems in NSCLC that can be overcome to incite macrophage-mediated anti-tumor immunity.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Fatores Reguladores de Interferon , Proteína Jagged-2 , Neoplasias Pulmonares , Camundongos Knockout , Macrófagos Associados a Tumor , Animais , Humanos , Camundongos , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Fatores Reguladores de Interferon/metabolismo , Fatores Reguladores de Interferon/genética , Proteína Jagged-1/metabolismo , Proteína Jagged-1/genética , Proteína Jagged-2/metabolismo , Proteína Jagged-2/genética , Proteína Jagged-2/imunologia , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Receptor Notch1/metabolismo , Receptor Notch1/genética , Receptores Notch/metabolismo , Transdução de Sinais , Evasão Tumoral/imunologia , Macrófagos Associados a Tumor/imunologia , Macrófagos Associados a Tumor/metabolismoRESUMO
Immunosuppressive macrophages restrict anti-cancer immunity in glioblastoma (GBM). Here, we studied the contribution of microglia (MGs) and monocyte-derived macrophages (MDMs) to immunosuppression and mechanisms underlying their regulatory function. MDMs outnumbered MGs at late tumor stages and suppressed T cell activity. Molecular and functional analysis identified a population of glycolytic MDM expressing GLUT1 with potent immunosuppressive activity. GBM-derived factors promoted high glycolysis, lactate, and interleukin-10 (IL-10) production in MDMs. Inhibition of glycolysis or lactate production in MDMs impaired IL-10 expression and T cell suppression. Mechanistically, intracellular lactate-driven histone lactylation promoted IL-10 expression, which was required to suppress T cell activity. GLUT1 expression on MDMs was induced downstream of tumor-derived factors that activated the PERK-ATF4 axis. PERK deletion in MDM abrogated histone lactylation, led to the accumulation of intratumoral T cells and tumor growth delay, and, in combination with immunotherapy, blocked GBM progression. Thus, PERK-driven glucose metabolism promotes MDM immunosuppressive activity via histone lactylation.
Assuntos
Glioblastoma , Glucose , Histonas , Macrófagos , Glioblastoma/imunologia , Glioblastoma/metabolismo , Glioblastoma/patologia , Animais , Histonas/metabolismo , Camundongos , Macrófagos/imunologia , Macrófagos/metabolismo , Glucose/metabolismo , Humanos , Linhagem Celular Tumoral , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Transportador de Glucose Tipo 1/metabolismo , Transportador de Glucose Tipo 1/genética , Interleucina-10/metabolismo , Glicólise , Microglia/metabolismo , Microglia/imunologia , Camundongos Endogâmicos C57BL , Linfócitos T/imunologia , Linfócitos T/metabolismo , Tolerância ImunológicaRESUMO
Some phages encode anti-CRISPR (acr) genes, which antagonize bacterial CRISPR-Cas immune systems by binding components of its machinery, but it is less clear how deployment of these acr genes impacts phage replication and epidemiology. Here, we demonstrate that bacteria with CRISPR-Cas resistance are still partially immune to Acr-encoding phage. As a consequence, Acr-phages often need to cooperate in order to overcome CRISPR resistance, with a first phage blocking the host CRISPR-Cas immune system to allow a second Acr-phage to successfully replicate. This cooperation leads to epidemiological tipping points in which the initial density of Acr-phage tips the balance from phage extinction to a phage epidemic. Furthermore, both higher levels of CRISPR-Cas immunity and weaker Acr activities shift the tipping points toward higher initial phage densities. Collectively, these data help elucidate how interactions between phage-encoded immune suppressors and the CRISPR systems they target shape bacteria-phage population dynamics.
Assuntos
Bacteriófagos/imunologia , Sistemas CRISPR-Cas/imunologia , Terapia de Imunossupressão , Pseudomonas aeruginosa/imunologia , Pseudomonas aeruginosa/virologia , Evolução Molecular , Modelos Teóricos , Pseudomonas aeruginosa/genéticaRESUMO
Glioblastoma (GBM), a highly lethal brain cancer, is notorious for immunosuppression, but the mechanisms remain unclear. Here, we documented a temporospatial patterning of tumor-associated myeloid cells (TAMs) corresponding to vascular changes during GBM progression. As tumor vessels transitioned from the initial dense regular network to later scant and engorged vasculature, TAMs shifted away from perivascular regions and trafficked to vascular-poor areas. This process was heavily influenced by the immunocompetence state of the host. Utilizing a sensitive fluorescent UnaG reporter to track tumor hypoxia, coupled with single-cell transcriptomics, we revealed that hypoxic niches attracted and sequestered TAMs and cytotoxic T lymphocytes (CTLs), where they were reprogrammed toward an immunosuppressive state. Mechanistically, we identified chemokine CCL8 and cytokine IL-1ß as two hypoxic-niche factors critical for TAM trafficking and co-evolution of hypoxic zones into pseudopalisading patterns. Therefore, perturbation of TAM patterning in hypoxic zones may improve tumor control.
Assuntos
Glioblastoma , Linfócitos T Citotóxicos , Humanos , Macrófagos Associados a Tumor , Macrófagos , Terapia de Imunossupressão , Glioblastoma/patologia , Microambiente TumoralRESUMO
Immune cells in the tumor microenvironment modulate cancer progression and are attractive therapeutic targets. Macrophages and T cells are key components of the microenvironment, yet their phenotypes and relationships in this ecosystem and to clinical outcomes are ill defined. We used mass cytometry with extensive antibody panels to perform in-depth immune profiling of samples from 73 clear cell renal cell carcinoma (ccRCC) patients and five healthy controls. In 3.5 million measured cells, we identified 17 tumor-associated macrophage phenotypes, 22 T cell phenotypes, and a distinct immune composition correlated with progression-free survival, thereby presenting an in-depth human atlas of the immune tumor microenvironment in this disease. This study revealed potential biomarkers and targets for immunotherapy development and validated tools that can be used for immune profiling of other tumor types.
Assuntos
Carcinoma de Células Renais/imunologia , Carcinoma de Células Renais/patologia , Neoplasias Renais/imunologia , Neoplasias Renais/patologia , Microambiente Tumoral , Humanos , Citometria por Imagem , Tolerância Imunológica , Rim/citologia , Macrófagos/imunologia , Macrófagos/patologia , Análise de Célula Única , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
Primary tumors are drivers of pre-metastatic niche formation, but the coordination by the secondary organ toward metastatic dissemination is underappreciated. Here, by single-cell RNA sequencing and immunofluorescence, we identified a population of cyclooxygenase 2 (COX-2)-expressing adventitial fibroblasts that remodeled the lung immune microenvironment. At steady state, fibroblasts in the lungs produced prostaglandin E2 (PGE2), which drove dysfunctional dendritic cells (DCs) and suppressive monocytes. This lung-intrinsic stromal program was propagated by tumor-associated inflammation, particularly the pro-inflammatory cytokine interleukin-1ß, supporting a pre-metastatic niche. Genetic ablation of Ptgs2 (encoding COX-2) in fibroblasts was sufficient to reverse the immune-suppressive phenotypes of lung-resident myeloid cells, resulting in heightened immune activation and diminished lung metastasis in multiple breast cancer models. Moreover, the anti-metastatic activity of DC-based therapy and PD-1 blockade was improved by fibroblast-specific Ptgs2 deletion or dual inhibition of PGE2 receptors EP2 and EP4. Collectively, lung-resident fibroblasts reshape the local immune landscape to facilitate breast cancer metastasis.
Assuntos
Neoplasias Pulmonares , Receptores de Prostaglandina E Subtipo EP2 , Ciclo-Oxigenase 2/genética , Fibroblastos/patologia , Humanos , Pulmão/patologia , Neoplasias Pulmonares/patologia , Receptores de Prostaglandina E Subtipo EP4/genética , Microambiente TumoralRESUMO
Understanding the mechanisms of HIV tissue persistence necessitates the ability to visualize tissue microenvironments where infected cells reside; however, technological barriers limit our ability to dissect the cellular components of these HIV reservoirs. Here, we developed protein and nucleic acid in situ imaging (PANINI) to simultaneously quantify DNA, RNA, and protein levels within these tissue compartments. By coupling PANINI with multiplexed ion beam imaging (MIBI), we measured over 30 parameters simultaneously across archival lymphoid tissues from healthy or simian immunodeficiency virus (SIV)-infected nonhuman primates. PANINI enabled the spatial dissection of cellular phenotypes, functional markers, and viral events resulting from infection. SIV infection induced IL-10 expression in lymphoid B cells, which correlated with local macrophage M2 polarization. This highlights a potential viral mechanism for conditioning an immunosuppressive tissue environment for virion production. The spatial multimodal framework here can be extended to decipher tissue responses in other infectious diseases and tumor biology.
Assuntos
Infecções por HIV , Ácidos Nucleicos , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia , Animais , Linfócitos T CD4-Positivos , Vírus de DNA , Terapia de Imunossupressão , Macaca mulatta , Macrófagos , Vírus da Imunodeficiência Símia/fisiologia , Carga ViralRESUMO
Sepsis results in elevated adenosine in circulation. Extracellular adenosine triggers immunosuppressive signaling via the A2a receptor (A2aR). Sepsis survivors develop persistent immunosuppression with increased risk of recurrent infections. We utilized the cecal ligation and puncture (CLP) model of sepsis and subsequent infection to assess the role of adenosine in post-sepsis immune suppression. A2aR-deficient mice showed improved resistance to post-sepsis infections. Sepsis expanded a subset of CD39hi B cells and elevated extracellular adenosine, which was absent in mice lacking CD39-expressing B cells. Sepsis-surviving B cell-deficient mice were more resistant to secondary infections. Mechanistically, metabolic reprogramming of septic B cells increased production of ATP, which was converted into adenosine by CD39 on plasmablasts. Adenosine signaling via A2aR impaired macrophage bactericidal activity and enhanced interleukin-10 production. Septic individuals exhibited expanded CD39hi plasmablasts and adenosine accumulation. Our study reveals CD39hi plasmablasts and adenosine as important drivers of sepsis-induced immunosuppression with relevance in human disease.
Assuntos
Adenosina/imunologia , Antígenos CD/imunologia , Apirase/imunologia , Tolerância Imunológica/imunologia , Macrófagos/imunologia , Plasmócitos/imunologia , Sepse/imunologia , Adenosina/metabolismo , Animais , Antígenos CD/metabolismo , Apirase/metabolismo , Reprogramação Celular/imunologia , Macrófagos/metabolismo , Camundongos , Plasmócitos/metabolismo , Receptor A2A de Adenosina/imunologia , Receptor A2A de Adenosina/metabolismo , Sepse/metabolismoRESUMO
The interferon (IFN) pathway is critical for cytotoxic T cell activation, which is central to tumor immunosurveillance and successful immunotherapy. We demonstrate here that PKCλ/ι inactivation results in the hyper-stimulation of the IFN cascade and the enhanced recruitment of CD8+ T cells that impaired the growth of intestinal tumors. PKCλ/ι directly phosphorylates and represses the activity of ULK2, promoting its degradation through an endosomal microautophagy-driven ubiquitin-dependent mechanism. Loss of PKCλ/ι results in increased levels of enzymatically active ULK2, which, by direct phosphorylation, activates TBK1 to foster the activation of the STING-mediated IFN response. PKCλ/ι inactivation also triggers autophagy, which prevents STING degradation by chaperone-mediated autophagy. Thus, PKCλ/ι is a hub regulating the IFN pathway and three autophagic mechanisms that serve to maintain its homeostatic control. Importantly, single-cell multiplex imaging and bioinformatics analysis demonstrated that low PKCλ/ι levels correlate with enhanced IFN signaling and good prognosis in colorectal cancer patients.
Assuntos
Neoplasias Colorretais/metabolismo , Interferons/metabolismo , Isoenzimas/metabolismo , Proteína Quinase C/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Transdução de Sinais , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Autofagia , Linfócitos T CD8-Positivos/metabolismo , Carcinogênese , Transformação Celular Neoplásica , Neoplasias Colorretais/mortalidade , Cicloeximida/química , Feminino , Células HEK293 , Humanos , Imunofenotipagem , Fator Regulador 3 de Interferon/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Pessoa de Meia-Idade , Transplante de Neoplasias , Fosforilação , Prognóstico , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição , Regulação para CimaRESUMO
Mutations affecting exon 9 of the CALR gene lead to the generation of a C-terminally modified calreticulin (CALR) protein that lacks the KDEL endoplasmic reticulum (ER) retention signal and consequently mislocalizes outside of the ER where it activates the thrombopoietin receptor in a cell-autonomous fashion, thus driving myeloproliferative diseases. Here, we used the retention using selective hooks (RUSH) assay to monitor the trafficking of CALR. We found that exon-9-mutated CALR was released from cells in response to the biotin-mediated detachment from its ER-localized hook, in vitro and in vivo. Cellular CALR release was confirmed in suitable mouse models bearing exon-9-mutated hematopoietic systems or tumors. Extracellular CALR mediated immunomodulatory effects and inhibited the phagocytosis of dying cancer cells by dendritic cells (DC), thereby suppressing antineoplastic immune responses elicited by chemotherapeutic agents or by PD-1 blockade. Altogether, our results demonstrate paracrine immunosuppressive effects for exon-9-mutated CALR.
Assuntos
Calreticulina/genética , Tolerância Imunológica/genética , Mutação , Neoplasias/genética , Neoplasias/imunologia , Animais , Calreticulina/metabolismo , Linhagem Celular Tumoral , Humanos , Camundongos , Camundongos Endogâmicos C57BL , FagocitoseRESUMO
Ferroptosis is a form of iron-dependent regulated cell death characterized by the accumulation of toxic lipid peroxides, particularly in the plasma membrane, leading to lytic cell death. While it plays a crucial role in maintaining the overall health and proper functioning of multicellular organisms, it can also contribute to tissue damage and pathological conditions. Although ferroptotic damage is generally recognized as an immunostimulatory process associated with the release of damage-associated molecular patterns (DAMPs), the occurrence of ferroptosis in immune cells or the release of immunosuppressive molecules can result in immune tolerance. Consequently, there is ongoing exploration of targeting the upstream signals or the machinery of ferroptosis to therapeutically enhance or inhibit the immune response. In addition to introducing the core molecular mechanisms of ferroptosis, we will focus on the immune characteristics of ferroptosis in pathological conditions, particularly in the context of infection, sterile inflammation, and tumor immunity.
Assuntos
Ferroptose , Humanos , Morte Celular , Tolerância Imunológica , Terapia de Imunossupressão , ImunizaçãoRESUMO
Serrated adenocarcinoma, an alternative pathway for colorectal cancer (CRC) development, accounts for 15%-30% of all CRCs and is aggressive and treatment resistant. We show that the expression of atypical protein kinase C ζ (PKCζ) and PKCλ/ι was reduced in human serrated tumors. Simultaneous inactivation of the encoding genes in the mouse intestinal epithelium resulted in spontaneous serrated tumorigenesis that progressed to advanced cancer with a strongly reactive and immunosuppressive stroma. Whereas epithelial PKCλ/ι deficiency led to immunogenic cell death and the infiltration of CD8+ T cells, which repressed tumor initiation, PKCζ loss impaired interferon and CD8+ T cell responses, which resulted in tumorigenesis. Combined treatment with a TGF-ß receptor inhibitor plus anti-PD-L1 checkpoint blockade showed synergistic curative activity. Analysis of human samples supported the relevance of these kinases in the immunosurveillance defects of human serrated CRC. These findings provide insight into avenues for the detection and treatment of this poor-prognosis subtype of CRC.
Assuntos
Mucosa Intestinal/imunologia , Neoplasias Intestinais/imunologia , Isoenzimas/imunologia , Proteína Quinase C/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/imunologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/metabolismo , Feminino , Humanos , Vigilância Imunológica/genética , Vigilância Imunológica/imunologia , Mucosa Intestinal/enzimologia , Mucosa Intestinal/patologia , Neoplasias Intestinais/enzimologia , Neoplasias Intestinais/genética , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Camundongos Knockout , Camundongos Transgênicos , Pessoa de Meia-Idade , Proteína Quinase C/genética , Proteína Quinase C/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismoRESUMO
Cyclin-dependent kinase 9 (CDK9) plays a critical role in transcription initiation and is essential for maintaining gene silencing at heterochromatic loci. Inhibition of CDK9 increases sensitivity to immunotherapy, but the underlying mechanism remains unclear. We now report that RNF20 stabilizes LSD1 via K29-mediated ubiquitination, which is dependent on CDK9-mediated phosphorylation. This CDK9- and RNF20-dependent LSD1 stabilization is necessary for the demethylation of histone H3K4, then subsequent repression of endogenous retrovirus, and an interferon response, leading to epigenetic immunosuppression. Moreover, we found that loss of RNF20 sensitizes cancer cells to the immune checkpoint inhibitor anti-PD-1 in vivo and that this effect can be rescued by the expression of ectopic LSD1. Our findings are supported by the observation that RNF20 levels correlate with LSD1 levels in human breast cancer specimens. This study sheds light on the role of RNF20 in CDK9-dependent LSD1 stabilization, which is crucial for epigenetic silencing and immunosuppression. Our findings explore the potential importance of targeting the CDK9-RNF20-LSD1 axis in the development of new cancer therapies.
Assuntos
Quinase 9 Dependente de Ciclina , Histona Desmetilases , Tolerância Imunológica , Ubiquitina-Proteína Ligases , Humanos , Quinase 9 Dependente de Ciclina/genética , Quinase 9 Dependente de Ciclina/metabolismo , Epigênese Genética , Histona Desmetilases/metabolismo , Histonas/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
While fundamental in their innate role in combating infection and responding to injury, neutrophils are emerging as key modulators of adaptive immune responses. Such functions are attained via both soluble and nonsoluble effectors that enable at least two major downstream outcomes: first, to mediate and control acute inflammatory responses and second, to regulate adaptive immunity and ultimately promoting the development and maintenance of immune tolerance either by releasing immuno-modulatory factors, including cytokines, or by directly interacting with cells of the adaptive immune system. Herein, we review these novel properties of neutrophils and redefine the pathophysiological functions of these fascinating multi-tasking cells, exploring the different mechanisms through which neutrophils are able to either enhance and orchestrate T cell pro-inflammatory responses or inhibit T cell activity to maintain immune tolerance.
Assuntos
Imunidade Inata , Neutrófilos , Humanos , Linfócitos T , Inflamação , Imunidade AdaptativaRESUMO
The natural history of advanced malignant melanoma demonstrates that, in most cases, widespread tumor dissemination is preceded by regional metastases involving tumor-draining lymph nodes [sentinel lymph nodes (SLNs)]. Under physiological conditions, LNs play a central role in immunosurveillance to non-self-antigens to which they are exposed via afferent lymph. The dysfunctional immunity in SLNs is mediated by tumor secretory factors that allow the survival of metastatic melanoma cells within the LN by creating a premetastatic niche (PMN). Recent studies outline the altered microenvironment of LNs shaped by melanoma mediators. Here, we discuss tumor secretory factors involved in subverting tumor immunity and remodeling LNs and highlight emerging therapeutic strategies to reinvigorate antitumoral immunity in SLNs.
Assuntos
Melanoma , Neoplasias Cutâneas , Humanos , Metástase Linfática/patologia , Melanoma/patologia , Neoplasias Cutâneas/patologia , Linfonodos , Microambiente TumoralRESUMO
Cancer-related inflammation plays a central role in the establishment of tumor-promoting mechanisms. Tumor-associated myeloid cells, which engage in complex interactions with cancer cells, as well as stromal and tumor immune infiltrating cells, promote cancer cell proliferation and survival, angiogenesis, and the generation of an immunosuppressive microenvironment. The complement system is one of the inflammatory mechanisms activated in the tumor microenvironment. Beside exerting anti-tumor mechanisms such as complement-dependent cytotoxicity and phagocytosis induced by therapeutic monoclonal antibodies, the complement system may promote immunosuppression and tumor growth and invasiveness, in particular, through the anaphylatoxins which target both leukocytes and cancer cells. In this review, we will discuss complement-mediated mechanisms acting on leukocytes, in particular on cells of the myelomonocytic cell lineage (macrophages, neutrophils, myeloid derived suppressor cells), which promote myeloid cell recruitment and functional skewing, leading to immunosuppression and resistance to tumor-specific immunity. Pre-clinical studies, which have elucidated the role of complement in activating pro-tumor mechanisms in myeloid cells, showing the relevance of these mechanisms in human, and therapeutic approaches based on complement targeting support the hypothesis that complement directly and indirectly interferes with many of the effector pathways associated with the cancer-immunity cycle, suggesting the relevance of complement targeting to improve responses to immunotherapeutic approaches.
Assuntos
Neoplasias , Humanos , Células Mieloides , Microambiente Tumoral , Terapia de Imunossupressão , Ativação do Complemento , Proteínas do Sistema Complemento/metabolismo , ImunoterapiaRESUMO
Antimicrobial resistance poses a serious threat to human health worldwide and its incidence continues to increase owing to the overuse of antibiotics and other factors. Macrolide antibiotics such as erythromycin (EM) have immunomodulatory effects in addition to their antibacterial activity. Long-term, low-dose administration of macrolides has shown clinical benefits in treating non-infectious inflammatory respiratory diseases. However, this practice may also increase the emergence of drug-resistant bacteria. In this study, we synthesized a series of EM derivatives, and screened them for two criteria: (i) lack of antibacterial activity and (ii) ability to suppress tumor necrosis factor-α (TNF-α) production in THP-1 cells stimulated with lipopolysaccharide. Among the 37 synthesized derivatives, we identified a novel 12-membered ring macrolide EM982 that lacked antibacterial activity against Staphylococcus aureus and suppressed the production of TNF-α and other cytokines. The effects of EM982 on Toll-like receptor 4 (TLR4) signaling were analyzed using a reporter assay and Western blotting. The reporter assay showed that EM982 suppressed the activation of transcription factors, NF-κB and/or activator protein 1 (AP-1), in HEK293 cells expressing human TLR4. Western blotting showed that EM982 inhibited the phosphorylation of both IκB kinase (IKK) ß and IκBα, which function upstream of NF-κB, whereas it did not affect the phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase, and c-Jun N-terminal kinase, which act upstream of AP-1. These results suggest that EM982 suppresses cytokine production by inhibiting phosphorylation of IKKß and IκBα, resulting in the inactivation of NF-κB.
Assuntos
Citocinas , Quinase I-kappa B , Inibidor de NF-kappaB alfa , Humanos , Quinase I-kappa B/metabolismo , Fosforilação/efeitos dos fármacos , Inibidor de NF-kappaB alfa/metabolismo , Citocinas/metabolismo , Eritromicina/farmacologia , Eritromicina/química , Células THP-1 , Fator de Necrose Tumoral alfa/metabolismo , Antibacterianos/farmacologia , Antibacterianos/química , Macrolídeos/farmacologia , Macrolídeos/química , NF-kappa B/metabolismo , Transdução de Sinais/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismoRESUMO
Immune checkpoint blockade (ICB) using monoclonal antibodies against programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) is the treatment of choice for cancer immunotherapy. However, low tissue permeability, immunogenicity, immune-related adverse effects, and high cost could be possibly improved using alternative approaches. On the other hand, synthetic low-molecular-weight (LMW) PD-1/PD-L1 blockers have failed to progress beyond in vitro studies, mostly due to low binding affinity or poor pharmacological characteristics resulting from their limited solubility and/or stability. Here, we report the development of polymer-based anti-human PD-L1 antibody mimetics (α-hPD-L1 iBodies) by attaching the macrocyclic peptide WL12 to a N-(2-hydroxypropyl)methacrylamide copolymer. We characterized the binding properties of iBodies using surface plasmon resonance, enzyme-linked immunosorbent assay, flow cytometry, confocal microscopy, and a cellular ICB model. We found that the α-hPD-L1 iBodies specifically target human PD-L1 (hPD-L1) and block the PD-1/PD-L1 interaction in vitro, comparable to the atezolizumab, durvalumab, and avelumab licensed monoclonal antibodies targeting PD-L1. Our findings suggest that iBodies can be used as experimental tools to target hPD-L1 and could serve as a platform to potentiate the therapeutic effect of hPD-L1-targeting small molecules by improving their affinity and pharmacokinetic properties.