RESUMO
Oncolytic viruses (OVs) selectively replicate in and destroy cancer cells resulting in anti-tumor immunity. However, clinical use remains a challenge because of virus clearance upon intravenous delivery. OV packaging using a nanomedicine approach could overcome this. Here we encapsulate an oncolytic adenovirus (Ad[I/PPT-E1A]) into CCL2-coated liposomes in order to exploit recruitment of CCR2-expressing circulating monocytes into tumors. We demonstrate successful encapsulation of Ad[I/PPT-E1A] into CCL2-coated liposomes that were preferentially taken up by CCR2-expressing monocytes. No complex-related toxicities were observed following incubation with prostate tumor cells and the encapsulation did not affect virus oncolytic activity in vitro. Furthermore, intravenous administration of our nanomedicine resulted in a significant reduction in tumor size and pulmonary metastasis in prostate cancer-bearing mice whereby a 1000-fold less virus was needed compared to Ad[I/PPT-E1A] alone. Taken together our data provide an opportunity to target OVs via circulation to inaccessible tumors using liposome-assisted drug delivery.
Assuntos
Adenoviridae , Terapia Viral Oncolítica , Adenoviridae/genética , Animais , Linhagem Celular Tumoral , Quimiocina CCL2/genética , Vetores Genéticos , Humanos , Lipossomos , Masculino , Camundongos , Monócitos , Terapia Viral Oncolítica/métodosRESUMO
The binding of vascular endothelial growth factor (VEGF) to VEGF receptor-2 (VEGFR-2) on the surface of vascular endothelial cells stimulates many steps in the angiogenic pathway. Inhibition of this interaction is proving of value in moderating the neovascularization accompanying age-related macular degeneration and in the treatment of cancer. Tissue inhibitor of metalloproteinases-3 (TIMP-3) has been shown to be a natural VEGFR-2 specific antagonist-an activity that is independent of its ability to inhibit metalloproteinases. In this investigation we localize this activity to the C-terminal domain of the TIMP-3 molecule and characterize a short peptide, corresponding to part of this domain, that not only inhibits all three VEGF-family receptors, but also fibroblast growth factor and platelet-derived growth factor receptors. This multiple-receptor inhibition may explain why the peptide was also seen to be a powerful inhibitor of tumour growth and also a partial inhibitor of arthritic joint inflammation in vivo.
Assuntos
Artrite/tratamento farmacológico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Peptídeos/farmacologia , Inibidor Tecidual de Metaloproteinase-3/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Artrite/metabolismo , Artrite/patologia , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Degeneração Macular/tratamento farmacológico , Degeneração Macular/metabolismo , Degeneração Macular/patologia , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/química , Inibidor Tecidual de Metaloproteinase-3/química , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
The paradigm for macrophage characterization has evolved from the simple M1/M2 dichotomy to a more complex model that encompasses the broad spectrum of macrophage phenotypic diversity, due to differences in ontogeny and/or local stimuli. We currently lack an in-depth pan-cancer single cell RNA-seq (scRNAseq) atlas of tumour-associated macrophages (TAMs) that fully captures this complexity. In addition, an increased understanding of macrophage diversity could help to explain the variable responses of cancer patients to immunotherapy. Our atlas includes well established macrophage subsets as well as a number of additional ones. We associate macrophage composition with tumour phenotype and show macrophage subsets can vary between primary and metastatic tumours growing in sites like the liver. We also examine macrophage-T cell functional cross talk and identify two subsets of TAMs associated with T cell activation. Analysis of TAM signatures in a large cohort of immune checkpoint inhibitor-treated patients (CPI1000 + ) identify multiple TAM subsets associated with response, including the presence of a subset of TAMs that upregulate collagen-related genes. Finally, we demonstrate the utility of our data as a resource and reference atlas for mapping of novel macrophage datasets using projection. Overall, these advances represent an important step in both macrophage classification and overcoming resistance to immunotherapies in cancer.
Assuntos
Imunoterapia , Neoplasias , Macrófagos Associados a Tumor , Humanos , Imunoterapia/métodos , Macrófagos Associados a Tumor/imunologia , Macrófagos Associados a Tumor/metabolismo , Neoplasias/imunologia , Neoplasias/terapia , Neoplasias/patologia , Neoplasias/genética , Microambiente Tumoral/imunologia , Análise de Célula Única , Linfócitos T/imunologia , RNA-Seq , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/farmacologia , Macrófagos/imunologia , Regulação Neoplásica da Expressão GênicaRESUMO
BACKGROUND: Androgen deprivation therapy (ADT) is a front-line treatment for prostate cancer. In some men, their tumors can become refractory leading to the development of castration-resistant prostate cancer (CRPC). This causes tumors to regrow and metastasize, despite ongoing treatment, and impacts negatively on patient survival. ADT is known to stimulate the accumulation of immunosuppressive cells like protumoral tumor-associated macrophages (TAMs), myeloid-derived suppressor cells and regulatory T cells in prostate tumors, as well as hypofunctional T cells. Protumoral TAMs have been shown to accumulate around tumor blood vessels during chemotherapy and radiotherapy in other forms of cancer, where they drive tumor relapse. Our aim was to see whether such perivascular (PV) TAMs also accumulate in ADT-treated prostate tumors prior to CRPC, and, if so, whether selectively inducing them to express a potent immunostimulant, interferon beta (IFNß), would stimulate antitumor immunity and delay CRPC. METHODS: We used multiplex immunofluorescence to assess the effects of ADT on the distribution and activation status of TAMs, CD8+T cells, CD4+T cells and NK cells in mouse and/or human prostate tumors. We then used antibody-coated, lipid nanoparticles (LNPs) to selectively target a STING agonist, 2'3'-cGAMP (cGAMP), to PV TAMs in mouse prostate tumors during ADT. RESULTS: TAMs accumulated at high density around blood vessels in response to ADT and expressed markers of a protumoral phenotype including folate receptor-beta (FR-ß), MRC1 (CD206), CD169 and VISTA. Additionally, higher numbers of inactive (PD-1-) CD8+T cells and reduced numbers of active (CD69+) NK cells were present in these PV tumor areas. LNPs coated with an antibody to FR-ß selectively delivered cGAMP to PV TAMs in ADT-treated tumors, where they activated STING and upregulated the expression of IFNß. This resulted in a marked increase in the density of active CD8+T cells (along with CD4+T cells and NK cells) in PV tumor areas, and significantly delayed the onset of CRPC. Antibody depletion of CD8+T cells during LNP administration demonstrated the essential role of these cells in delay in CRPC induced by LNPs. CONCLUSION: Together, our data indicate that targeting a STING agonist to PV TAMs could be used to extend the treatment window for ADT in prostate cancer.
Assuntos
Macrófagos , Proteínas de Membrana , Masculino , Animais , Camundongos , Proteínas de Membrana/metabolismo , Proteínas de Membrana/agonistas , Macrófagos/metabolismo , Macrófagos/imunologia , Macrófagos/efeitos dos fármacos , Humanos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/patologia , Antagonistas de Androgênios/uso terapêutico , Antagonistas de Androgênios/farmacologia , Macrófagos Associados a Tumor/metabolismo , Macrófagos Associados a Tumor/efeitos dos fármacos , Macrófagos Associados a Tumor/imunologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Resistencia a Medicamentos AntineoplásicosRESUMO
Macrophages play an essential role in tissue homeostasis, innate immunity, inflammation, and wound repair. Macrophages are also essential during development, severely limiting the use of mouse models in which these cells have been constitutively deleted. Consequently, we have developed a transgenic model of inducible macrophage depletion in which macrophage-specific induction of the cytotoxic diphtheria toxin A chain (DTA) is achieved by administration of doxycycline. Induction of the DTA protein in transgenic animals resulted in a significant 50% reduction in CD68+ macrophages of the liver, spleen, and bone over a period of 6 weeks. Pertinently, the macrophages remaining after doxycycline treatment were substantially smaller and are functionally impaired as shown by reduced inflammatory cytokine production in response to lipopolysaccharide. This inducible model of macrophage depletion can now be utilized to determine the role of macrophages in both development and animal models of chronic inflammatory diseases.
Assuntos
Macrófagos/fisiologia , Camundongos Transgênicos , Modelos Animais , Animais , Antígenos CD/imunologia , Antígenos de Diferenciação Mielomonocítica/imunologia , Osso e Ossos/citologia , Citocinas/imunologia , Toxina Diftérica/genética , Doxiciclina/toxicidade , Terapia de Imunossupressão , Lipopolissacarídeos/imunologia , Fígado/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Fragmentos de Peptídeos/genética , Baço/citologiaRESUMO
Angiopoietin 2 (ANGPT2) is a proangiogenic cytokine whose expression is often upregulated by endothelial cells in tumors. Expression of its receptor, TIE2, defines a highly proangiogenic subpopulation of myeloid cells in circulation and tumors called TIE2-expressing monocytes/macrophages (TEMs). Genetic depletion of TEMs markedly reduces tumor angiogenesis in various tumor models, emphasizing their essential role in driving tumor progression. Previously, we demonstrated that ANGPT2 augments the expression of various proangiogenic genes, the potent immunosuppressive cytokine, IL-10, and a chemokine for regulatory T cells (Tregs), CCL17 by TEMs in vitro. We now show that TEMs also express higher levels of IL-10 than TIE2(-) macrophages in tumors and that ANGPT2-stimulated release of IL-10 by TEMs suppresses T cell proliferation, increases the ratio of CD4(+) T cells to CD8(+) T cells, and promotes the expansion of CD4(+)CD25(high)FOXP3(+) Tregs. Furthermore, syngeneic murine tumors expressing high levels of ANGPT2 contained not only high numbers of TEMs but also increased numbers of Tregs, whereas genetic depletion of tumor TEMs resulted in a marked reduction in the frequency of Tregs in tumors. Taken together, our data suggest that ANGPT2-stimulated TEMs represent a novel, potent immunosuppressive force in tumors.
Assuntos
Angiopoietina-2/fisiologia , Proteínas de Ciclo Celular/fisiologia , Diferenciação Celular/imunologia , Proteínas de Ligação a DNA/fisiologia , Ativação Linfocitária/imunologia , Monócitos/imunologia , Neovascularização Patológica/imunologia , Proteínas Repressoras/fisiologia , Linfócitos T Reguladores/imunologia , Fatores de Transcrição/fisiologia , Animais , Proteínas Reguladoras de Apoptose , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/patologia , Proteínas de Ciclo Celular/biossíntese , Linhagem Celular Tumoral , Técnicas de Cocultura , Proteínas de Ligação a DNA/biossíntese , Inibidores do Crescimento/biossíntese , Inibidores do Crescimento/fisiologia , Humanos , Interleucina-10/biossíntese , Interleucina-10/metabolismo , Interleucina-10/fisiologia , Macrófagos/imunologia , Macrófagos/metabolismo , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Monócitos/metabolismo , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Proteínas Repressoras/biossíntese , Linfócitos T Reguladores/citologia , Fatores de Transcrição/biossínteseAssuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Macrófagos/fisiologia , Animais , Neoplasias da Mama/imunologia , Contagem de Células , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Modelos Biológicos , Metástase Neoplásica/tratamento farmacológico , Neutrófilos/imunologia , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , Prognóstico , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/fisiologia , Microambiente Tumoral/fisiologiaRESUMO
Neutrophils are important innate immune cells that are involved in microbial clearance at sites of infection and in wound healing. The microenvironment of tumors often resembles that of chronic inflammation and increased numbers of neutrophils have been observed in several tumors and, in some cases, these positively correlate with poor prognosis. Neutrophil recruitment into tumors appears to be dependent on chemokines that bind to CXCR1 and CXCR2 expressed by neutrophils. In our study, we used lung adenocarcinoma A549 multicellular tumor spheroids and A549 tumor xenografts along with a CXCR2-specific small molecule inhibitor (AZ10397767) to investigate the recruitment and function of human neutrophils in tumors. We found that A549 spheroids constitutively secrete high levels of CXCL chemokines and that neutrophil recruitment into A549 tumors in vitro and in vivo is largely dependent on CXCR2 activation. AZ10397767 significantly reduced the numbers of infiltrating neutrophils into both in vitro and in vivo tumor models, which was associated with slower growing tumors. Neutrophil infiltration into A549 tumor spheroids increased their size compared to noninfiltrated spheroids and neutrophil-derived factors increased the proliferation of A549 tumor cells and induced endothelial cell tubule formation in vitro. In contrast, we saw no reduction in microvascular density in AZ10397767-treated A549 tumors or in tumors grown in CXCR2(-/-) mice, suggesting that angiogenesis in these tumors is CXCR2-independent. Our data show that neutrophils can contribute to lung tumor growth and that CXCR2 antagonists may be a useful therapeutic agent in the treatment of lung carcinomas.
Assuntos
Adenocarcinoma/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Melanoma/tratamento farmacológico , Infiltração de Neutrófilos/efeitos dos fármacos , Quinazolinas/uso terapêutico , Receptores de Interleucina-8B/antagonistas & inibidores , Triazóis/uso terapêutico , Adenocarcinoma/imunologia , Adenocarcinoma/metabolismo , Animais , Western Blotting , Proliferação de Células , Quimiotaxia , Meios de Cultivo Condicionados/farmacologia , Ensaio de Imunoadsorção Enzimática , Humanos , Técnicas Imunoenzimáticas , Técnicas In Vitro , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/metabolismo , Melanoma/imunologia , Melanoma/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , RNA Mensageiro/genética , Receptores de Interleucina-8B/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Esferoides Celulares , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
It is now established that bone marrow-derived myeloid cells regulate tumor angiogenesis. This was originally inferred from studies of human tumor biopsies in which a positive correlation was seen between the number of tumor-infiltrating myeloid cells, such as macrophages and neutrophils, and tumor microvessel density. However, unequivocal evidence was only provided once mouse models were used to examine the effects on tumor angiogenesis by genetically or pharmacologically targeting myeloid cells. Since then, identifying the exact myeloid cell types involved in this process has proved challenging because of myeloid cell heterogeneity and the expression of overlapping phenotypic markers in tumors. As a result, investigators often simply refer to them now as "bone marrow-derived myeloid cells." Here we review the findings of various attempts to phenotype the myeloid cells involved and discuss the therapeutic implications of correctly identifying-and thus being able to target-this proangiogenic force in tumors.
Assuntos
Células Mieloides/citologia , Neovascularização Patológica , Animais , Células da Medula Óssea/citologia , Linhagem da Célula , Progressão da Doença , Humanos , Macrófagos/citologia , Camundongos , Monócitos/citologia , Neoplasias/patologia , FenótipoRESUMO
The pivotal role of tumor-associated macrophages (TAMs) in tumor progression is now well established. TAMs have been shown to influence multiple steps in tumor development including the growth, survival, invasion, and metastasis of tumor cells as well as angiogenesis and lymphangiogenesis in tumors. The molecular circuits that polarize TAMs toward such a protumoral phenotype are now the focus of intense investigation. The transcription factor, nuclear factor-kappaB (NF-kappaB), is a master regulator of many cellular processes and been shown to regulate various pathways that impact on the function of TAMs. Much evidence for this has come from the use of elegant transgenic murine tumor models in which modification of single components of the NF-kappaB signaling pathway has been shown to regulate the pro-tumor repertoire of TAMs. Here, we outline this evidence and attempt to reconcile the various views that have emerged recently over the exact role of NF-kappaB in this phenomenon.
Assuntos
Macrófagos/fisiologia , NF-kappa B/fisiologia , Neoplasias/imunologia , Animais , Progressão da Doença , Humanos , Macrófagos/imunologia , Macrófagos/patologia , Modelos Biológicos , Neoplasias/patologia , Neoplasias/fisiopatologia , Transdução de Sinais/imunologia , Transdução de Sinais/fisiologiaRESUMO
Ischemia exists in many diseased tissues, including arthritic joints, atherosclerotic plaques, and malignant tumors. Macrophages accumulate in these sites and up-regulate hypoxia-inducible transcription factors (HIFs) 1 and 2 in response to the hypoxia present. Here we show that the gene expression profile in primary human and murine macrophages changes markedly when they are exposed to hypoxia for 18 hours. For example, they were seen to up-regulate the cell surface receptors, CXCR4 and GLUT1, and the potent, tumor-promoting cytokines, vascular endothelial growth factor A, interleukin (IL)-1beta and IL-8, adrenomedullin, CXCR4, and angiopoietin-2. Hypoxia also stimulated their expression and/or phosphorylation of various proteins in the nuclear factor-kappaB (NF-kappaB) signaling pathway. We then used both genetic and pharmacologic methods to manipulate the levels of HIFs-1alpha and 2alpha or NF-kappaB in primary macrophages to elucidate their role in the hypoxic induction of many of these key genes. These studies showed that both HIF-1 and -2, but not NF-kappaB, are important transcriptional effectors regulating the responses of macrophages to such a period of hypoxia. Further studies using experimental mouse models are now warranted to investigate the role of such macrophage responses in the progression of various diseased tissues, such as malignant tumors.
Assuntos
Fator 1 Induzível por Hipóxia/fisiologia , Macrófagos/fisiologia , Fatores de Transcrição/fisiologia , Animais , Técnicas de Cultura de Células , Hipóxia Celular/genética , Células Cultivadas , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Fator 1 Induzível por Hipóxia/genética , Fator 1 Induzível por Hipóxia/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Transgênicos , NF-kappa B/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Androgen deprivation therapy (ADT) is the front-line treatment for early and metastatic prostate cancer, and the development of tumor resistance to it has major clinical consequences. Cancer cells start to proliferate and tumors begin to regrow, requiring the administration of more generic anticancer treatments like surgery, radiotherapy, and/or chemotherapy. Tumor-associated macrophages are known to drive tumor resistance to a number of anti-cancer therapies. El-Kenawi and colleagues now demonstrate a novel mechanism underpinning their ability to do so in prostate tumors during ADT. This involves the accumulation of cholesterol by macrophages in tumors and its transfer to cancer cells, where it acts as a precursor for androgen biosynthesis and results in the activation of androgen receptors.See related article by El-Kenawi and colleagues, p. 5477.
Assuntos
Antagonistas de Androgênios , Neoplasias de Próstata Resistentes à Castração , Antagonistas de Androgênios/uso terapêutico , Humanos , Macrófagos , Masculino , Receptores AndrogênicosRESUMO
Oncolytic viruses (OV) have been shown to activate the antitumor functions of specific immune cells like T cells. Here, we show OV can also reprogram tumor-associated macrophage (TAM) to a less immunosuppressive phenotype. Syngeneic, immunocompetent mouse models of primary breast cancer were established using PyMT-TS1, 4T1, and E0771 cell lines, and a metastatic model of breast cancer was established using the 4T1 cell line. Tumor growth and overall survival was assessed following intravenous administration of the OV, HSV1716 (a modified herpes simplex virus). Infiltration and function of various immune effector cells was assessed by NanoString, flow cytometry of dispersed tumors, and immunofluorescence analysis of tumor sections. HSV1716 administration led to marked tumor shrinkage in primary mammary tumors and a decrease in metastases. This was associated with a significant increase in the recruitment/activation of cytotoxic T cells, a reduction in the presence of regulatory T cells and the reprograming of TAMs towards a pro-inflammatory, less immunosuppressive phenotype. These findings were supported by in vitro data demonstrating that human monocyte-derived macrophages host HSV1716 replication, and that this led to immunogenic macrophage lysis. These events were dependent on macrophage expression of proliferating cell nuclear antigen (PCNA). Finally, the antitumor effect of OV was markedly diminished when TAMs were depleted using clodronate liposomes. Together, our results show that TAMs play an essential role in support of the tumoricidal effect of the OV, HSV1716-they both host viral replication via a novel, PCNA-dependent mechanism and are reprogramed to express a less immunosuppressive phenotype.
Assuntos
Macrófagos/metabolismo , Vírus Oncolíticos/patogenicidade , Animais , Modelos Animais de Doenças , Feminino , Humanos , Neoplasias Mamárias Animais , Camundongos , TransfecçãoRESUMO
Tumor-associated macrophages (TAMs) are a prominent inflammatory cell population in many tumor types residing in both perivascular and avascular, hypoxic regions of these tissues. Analysis of TAMs in human tumor biopsies has shown that they express a variety of tumor-promoting factors and evidence from transgenic murine tumor models has provided unequivocal evidence for the importance of these cells in driving angiogenesis, lymphangiogenesis, immunosuppression, and metastasis. This review will summarize the mechanisms by which monocytes are recruited into tumors, their myriad, tumor-promoting functions within tumors, and the influence of the tumor microenvironment in driving these activities. We also discuss recent attempts to both target/destroy TAMs and exploit them as delivery vehicles for anti-cancer gene therapy.
Assuntos
Macrófagos/fisiologia , Neoplasias/fisiopatologia , Humanos , Terapia de Imunossupressão , Linfangiogênese , Invasividade Neoplásica , Metástase Neoplásica , Neovascularização Patológica , Evasão TumoralRESUMO
BACKGROUND AND PURPOSE: White matter lesions (WML) in brain aging are linked to dementia and depression. Ischemia contributes to their pathogenesis but other mechanisms may contribute. We used RNA microarray analysis with functional pathway grouping as an unbiased approach to investigate evidence for additional pathogenetic mechanisms. METHODS: WML were identified by MRI and pathology in brains donated to the Medical Research Council Cognitive Function and Ageing Study Cognitive Function and Aging Study. RNA was extracted to compare WML with nonlesional white matter samples from cases with lesions (WM[L]), and from cases with no lesions (WM[C]) using RNA microarray and pathway analysis. Functional pathways were validated for selected genes by quantitative real-time polymerase chain reaction and immunocytochemistry. RESULTS: We identified 8 major pathways in which multiple genes showed altered RNA transcription (immune regulation, cell cycle, apoptosis, proteolysis, ion transport, cell structure, electron transport, metabolism) among 502 genes that were differentially expressed in WML compared to WM[C]. In WM[L], 409 genes were altered involving the same pathways. Genes selected to validate this microarray data all showed the expected changes in RNA levels and immunohistochemical expression of protein. CONCLUSIONS: WML represent areas with a complex molecular phenotype. From this and previous evidence, WML may arise through tissue ischemia but may also reflect the contribution of additional factors like blood-brain barrier dysfunction. Differential expression of genes in WM[L] compared to WM[C] indicate a "field effect" in the seemingly normal surrounding white matter.
Assuntos
Vias Biossintéticas/genética , Encefalopatias/genética , Encefalopatias/patologia , Encéfalo/patologia , RNA/biossíntese , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/patologia , Encéfalo/crescimento & desenvolvimento , Química Encefálica/genética , Feminino , Humanos , Imuno-Histoquímica , Imageamento por Ressonância Magnética , Masculino , Proteínas do Tecido Nervoso/genética , Análise de Sequência com Séries de Oligonucleotídeos , RNA/análise , RNA/genética , RNA Complementar/biossíntese , RNA Complementar/genética , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
It is now well known that most malignant tumours contain a significant amount of leucocytic infiltrates the presence of which has, on many occasions, been linked to poor patient prognosis. These leucocyte populations are recruited to tumours by chemotactic factors released by either viable or necrotic tumour cells, or by cells within the tumour stroma. In recent times, most studies have analysed the role that tumour-associated macrophages (TAM) have on tumour progression. However, there is now increasing evidence to show that neutrophils also actively participate in this process. Whilst there are some data to suggest that neutrophil-derived factors can promote genetic mutations leading to tumourigenesis, or secrete factors that promote tumour cell proliferation; there is now substantial evidence to show that neutrophils, like TAM, significantly affect tumour angiogenesis. In this review, we discuss the likely mechanisms by which neutrophils are recruited into the tumour and then elaborate on how these cells may induce tumour vascularization by the secretion of powerful pro-angiogenic factors. We also discuss possible future chemotherapeutic strategies that are aimed at limiting tumour angiogenesis by inhibiting neutrophil recruitment.
Assuntos
Neoplasias/irrigação sanguínea , Neovascularização Patológica/patologia , Neutrófilos/fisiologia , Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Humanos , Infiltração de Neutrófilos/efeitos dos fármacos , Neutrófilos/efeitos dos fármacosRESUMO
Recent findings indicate that tumor-associated macrophages are important drivers of tumor angiogenesis. Here, we review the essential role played by Tie2-expressing monocytes (TEM) in this phenomenon. TEMs are present in human blood and tumors and their elimination in various tumor models suppresses tumor angiogenesis. A ligand for Tie2, angiopoietin-2 (Ang-2), is produced by angiogenic tumor vessels and is a chemoattractant for TEMs. Hypoxia up-regulates Tie2 expression on TEMs and, together with Ang-2, down-regulates their antitumor functions. Learning more about the regulation of TEMs by the tumor microenvironment may yield new strategies to ablate the tumor vasculature.
Assuntos
Angiopoietina-2/metabolismo , Monócitos/enzimologia , Neoplasias/irrigação sanguínea , Neoplasias/enzimologia , Receptor TIE-2/biossíntese , Angiopoietina-2/biossíntese , Angiopoietina-2/genética , Animais , Hipóxia Celular , Humanos , Neoplasias/sangue , Neoplasias/genética , Neovascularização Patológica/sangue , Neovascularização Patológica/enzimologia , Receptor TIE-2/genética , Regulação para CimaRESUMO
Cytotoxic chemotherapy is an effective treatment for invasive breast cancer. However, experimental studies in mice also suggest that chemotherapy has pro-metastatic effects. Primary tumours release extracellular vesicles (EVs), including exosomes, that can facilitate the seeding and growth of metastatic cancer cells in distant organs, but the effects of chemotherapy on tumour-derived EVs remain unclear. Here we show that two classes of cytotoxic drugs broadly employed in pre-operative (neoadjuvant) breast cancer therapy, taxanes and anthracyclines, elicit tumour-derived EVs with enhanced pro-metastatic capacity. Chemotherapy-elicited EVs are enriched in annexin A6 (ANXA6), a Ca2+-dependent protein that promotes NF-κB-dependent endothelial cell activation, Ccl2 induction and Ly6C+CCR2+ monocyte expansion in the pulmonary pre-metastatic niche to facilitate the establishment of lung metastasis. Genetic inactivation of Anxa6 in cancer cells or Ccr2 in host cells blunts the pro-metastatic effects of chemotherapy-elicited EVs. ANXA6 is detected, and potentially enriched, in the circulating EVs of breast cancer patients undergoing neoadjuvant chemotherapy.
Assuntos
Doxorrubicina/uso terapêutico , Vesículas Extracelulares/efeitos dos fármacos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Paclitaxel/uso terapêutico , Animais , Anexina A6/metabolismo , Linhagem Celular Tumoral , Quimiocina CCL2/metabolismo , Vesículas Extracelulares/metabolismo , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Nus , Camundongos TransgênicosRESUMO
The hypoxia-inducible transcription factor HIF-1 is appreciated as a promising target for cancer therapy. However, conditional deletion of HIF-1 and HIF-1 target genes in cells of the tumor microenvironment can result in accelerated tumor growth, calling for a detailed characterization of the cellular context to fully comprehend HIF-1's role in tumorigenesis. We dissected cell type-specific functions of HIF-1 for intestinal tumorigenesis by lineage-restricted deletion of the Hif1a locus. Intestinal epithelial cell-specific Hif1a loss reduced activation of Wnt/ß-catenin, tumor-specific metabolism and inflammation, significantly inhibiting tumor growth. Deletion of Hif1a in myeloid cells reduced the expression of fibroblast-activating factors in tumor-associated macrophages resulting in decreased abundance of tumor-associated fibroblasts (TAF) and robustly reduced tumor formation. Interestingly, hypoxia was detectable only sparsely and without spatial association with HIF-1α, arguing for an importance of hypoxia-independent, i.e., non-canonical, HIF-1 stabilization for intestinal tumorigenesis that has not been previously appreciated. This adds a further layer of complexity to the regulation of HIF-1 and suggests that hypoxia and HIF-1α stabilization can be uncoupled in cancer. Collectively, our data show that HIF-1 is a pivotal pro-tumorigenic factor for intestinal tumor formation, controlling key oncogenic programs in both the epithelial tumor compartment and the tumor microenvironment.
Assuntos
Neoplasias Colorretais/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Animais , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Feminino , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oncogenes , Estabilidade Proteica , Microambiente TumoralRESUMO
The cytokine MIF is over-expressed in tumors and is associated with tumor proliferation, angiogenesis and metastasis. Hypoxia, a hallmark feature of tumors, increases MIF expression from tumor cells. We examined the role of hypoxia-inducible transcription factors on MIF secretion from MCF-7 breast carcinoma cells. Secretion of MIF was induced by hypoxia after 24h but up-regulation of MIF mRNA was minimal. Inhibition of HIF-1alpha, HIF-2alpha, NF-kappaB and C/EBPbeta using siRNA had no effect on hypoxia-induced MIF secretion. However, inhibition of transcription and translation significantly decreased MIF production, suggesting that hypoxia-induced secretion of MIF in MCF-7 cells is via an alternative pathway.