RESUMO
Mast cells (MCs) are tissue resident sentinels that mature and orchestrate inflammation in response to infection and allergy. While they are also frequently observed in tumors, the contribution of MCs to carcinogenesis remains unclear. Here, we show that sequential oncogenic events in gut epithelia expand different types of MCs in a temporal-, spatial-, and cytokine-dependent manner. The first wave of MCs expands focally in benign adenomatous polyps, which have elevated levels of IL-10, IL-13, and IL-33, and are rich in type-2 innate lymphoid cells (ILC2s). These vanguard MCs adhere to the transformed epithelial cells and express murine mast cell protease 2 (mMCP2; a typical mucosal MC protease) and, to a lesser extent, the connective tissue mast cell (CTMC) protease mMCP6. Persistence of MCs is strictly dependent on T cell-derived IL-10, and their loss in the absence of IL-10-expressing T cells markedly delays small bowel (SB) polyposis. MCs expand profusely in polyposis-prone mice when T cells overexpress IL-10. The frequency of polyp-associated MCs is unaltered in response to broad-spectrum antibiotics, arguing against a microbial component driving their recruitment. Intriguingly, when polyps become invasive, a second wave of mMCP5+/mMCP6+ CTMCs expands in the tumor stroma and at invasive tumor borders. Ablation of mMCP6 expression attenuates polyposis, but invasive properties of the remaining lesions remain intact. Our findings argue for a multistep process in SB carcinogenesis in which distinct MC subsets, and their elaborated proteases, guide disease progression.
Assuntos
Quimases/metabolismo , Citocinas/metabolismo , Neoplasias Intestinais/patologia , Intestino Delgado/patologia , Linfócitos/patologia , Mastócitos/patologia , Mucosa/patologia , Animais , Células Cultivadas , Neoplasias Intestinais/imunologia , Neoplasias Intestinais/metabolismo , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Linfócitos/imunologia , Linfócitos/metabolismo , Mastócitos/imunologia , Mastócitos/metabolismo , Camundongos , Mucosa/imunologia , Mucosa/metabolismo , Estadiamento de NeoplasiasRESUMO
OBJECTIVES: Lung cancer is the leading cause of cancer-related death in the USA. Regulatory T cells (Tregs) normally function to temper immune responses and decrease inflammation. Previous research has demonstrated different subsets of Tregs with contrasting anti- or pro-inflammatory properties. This study aimed to determine Treg subset distributions and characteristics present in non-small cell lung cancer (NSCLC) patients. METHODS: Peripheral blood was collected from healthy controls (HC) and NSCLC patients preceding surgical resection, and mononuclear cells were isolated, stained, and analyzed by flow cytometry. Tregs were defined by expression of CD4 and CD25 and classified into CD45RA(+)Foxp3(int) (naïve, Fr. I) or CD45RA(-)Foxp3(hi) (activated Fr. II). Activated conventional T cells were CD4(+)CD45RA(-)Foxp3(int) (Fr. III). RESULTS: Samples from 23 HC and 26 NSCLC patients were collected. Tregs isolated from patients with NSCLC were found to have enhanced suppressive function on naive T cells. Cancer patients had significantly increased frequencies of activated Tregs (fraction II: FrII), 17.5 versus 3.2% (P < 0.001). FrII Tregs demonstrated increased RORγt and IL17 expression and decreased IL10 expression compared to Tregs from HC, indicating pro-inflammatory characteristics. CONCLUSIONS: This study demonstrates that a novel subset of Tregs with pro-inflammatory characteristics preferentially expand in NSCLC patients. This Treg subset appears identical to previously reported pro-inflammatory Tregs in human colon cancer patients and in mouse models of polyposis. We expect the pro-inflammatory Tregs in lung cancer to contribute to the immune pathogenesis of disease and propose that targeting this Treg subset may have protective benefits in NSCLC.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Neoplasias Pulmonares/imunologia , Linfócitos T Reguladores/imunologia , Idoso , Feminino , Humanos , Ativação Linfocitária , MasculinoRESUMO
IL10 is attributed with immune-suppressive and anti-inflammatory properties, which could promote or suppress cancer in the gastrointestinal tract. Loss of IL10 exacerbates colonic inflammation, leading to colitis and cancer. Consistent with this, transfer of IL10-competent regulatory T cells (Treg) into mice with colitis or hereditary polyposis protects against disease, while IL10-deficient mice are predisposed to polyposis with increased colon polyp load. Little is known about the protective or pathogenic function of IL10 in cancers of the small intestine. We found CD4(+) T cells and CD4(+) Foxp3(+) Tregs to be the major sources of IL10 in the small intestine and responsible for the increase in IL10 during polyposis in the APC(Δ468) mouse model of hereditary polyposis. Targeted ablation of IL10 in T cells caused severe IL10 deficiency and delayed polyp growth. However, these polyps progressively lost cytotoxic activity and eventually progressed to cancer. Several observations suggested that the effect was due to the loss of IFNγ-dependent immune surveillance. IL10-incompetent CD4(+) T cells failed to secrete IFNγ when stimulated with polyp antigens and were inefficient in T-helper-1 (TH1) commitment. By contrast, the TH17 commitment was unaffected. These findings were validated using mice whose T cells overexpress IL10. In these mice, we observed high intra-polyp cytotoxic activity and attenuation of polyposis. Thus, expression of IL10 by T cells is protective and required for immune surveillance in the small intestine.
Assuntos
Vigilância Imunológica , Interleucina-10/imunologia , Neoplasias Intestinais/imunologia , Intestino Delgado/patologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
PURPOSE: Leukotrienes and prostaglandins, products of arachidonic acid metabolism, sustain both systemic and lesion-localized inflammation. Tumor-associated Inflammation can also contribute to the pathogenesis of colon cancer. Patients with inflammatory bowel disease (IBD) have increased risk of developing colon cancer. The levels of 5-lipoxygenase (5-LO), the key enzyme for leukotrienes production, are increased in colon cancer specimens and colonic dysplastic lesions. Here we report that Zileuton, a specific 5-LO inhibitor, can prevent polyp formation by efficiently reducing the tumor-associated and systemic inflammation in APCΔ468 mice. EXPERIMENTAL DESIGN: In the current study, we inhibited 5-LO by dietary administration of Zileuton in the APCΔ468 mouse model of polyposis and analyzed the effect of in vivo 5-LO inhibition on tumor-associated and systemic inflammation. RESULTS: Zileuton-fed mice developed fewer polyps and displayed marked reduction in systemic and polyp-associated inflammation. Pro-inflammatory cytokines and pro-inflammatory innate and adaptive immunity cells were reduced both in the lesions and systemically. As part of tumor-associated inflammation Leukotriene B4 (LTB4), product of 5-LO activity, is increased focally in human dysplastic lesions. The 5-LO enzymatic activity was reduced in the serum of Zileuton treated polyposis mice. CONCLUSIONS: This study demonstrates that dietary administration of 5-LO specific inhibitor in the polyposis mouse model decreases polyp burden, and suggests that Zileuton may be a potential chemo-preventive agent in patients that are high-risk of developing colon cancer.
Assuntos
Hidroxiureia/análogos & derivados , Doenças Inflamatórias Intestinais/prevenção & controle , Polipose Intestinal/prevenção & controle , Inibidores de Lipoxigenase/farmacologia , Animais , Neoplasias do Colo/patologia , Neoplasias do Colo/prevenção & controle , Modelos Animais de Doenças , Feminino , Humanos , Hidroxiureia/farmacologia , Doenças Inflamatórias Intestinais/patologia , Polipose Intestinal/patologia , Masculino , Camundongos , Camundongos MutantesRESUMO
Tumor growth requires interactions of tumor cells with a receptive and inductive microenvironment. Two major populations of tumor-infiltrating cells are considered to be essential for producing such a microenvironment: (1) proinflammatory cells that nurture the tumor with growth factors and facilitate invasion and metastasis by secreting proteases and (2) immune suppressive leukocytes including T-regulatory cells (Treg) that hinder tumor-specific CD8 T-cell responses, which otherwise could potentially reject the tumor. Among the proinflammatory cells, accumulation of mast cells (MCs) in human tumors is frequently recorded and was recently linked with poor prognosis. Causative links between mast cell infiltration and tumor progression can be deduced from animal studies. There is an interesting link between mast cells and Treg. The adoptive transfer of Treg from healthy syngeneic mice to mice susceptible to colon cancer suppresses focal mastocytosis and hinders tumor progression. Furthermore, T-cell-deficient mice susceptible to colon cancer show enhanced focal mastocytosis and tumor invasion. Here, we describe methods to assess MCs in mouse models of cancer and to investigate how MCs affect tumor epithelium. Additionally, we will detail methods used to investigate how T cells influence MCs and how MCs influence T cells.
Assuntos
Neoplasias Intestinais/imunologia , Mastócitos/citologia , Transferência Adotiva , Animais , Células da Medula Óssea/citologia , Degranulação Celular , Proliferação de Células , Separação Celular , Meios de Cultivo Condicionados , Esterases/metabolismo , Feminino , Humanos , Neoplasias Intestinais/patologia , Polipose Intestinal/imunologia , Intestinos/imunologia , Mastócitos/imunologia , Mastócitos/metabolismo , Camundongos , Invasividade Neoplásica , Coloração e Rotulagem , Linfócitos T/imunologia , Cloreto de Tolônio/metabolismo , Triptases/metabolismoRESUMO
The density and type of lymphocytes that infiltrate colon tumors are predictive of the clinical outcome of colon cancer. High densities of T helper 17 (T(H)17) cells and inflammation predict poor outcome, whereas infiltration by T regulatory cells (Tregs) that naturally suppress inflammation is associated with longer patient survival. However, the role of Tregs in cancer remains controversial. We recently reported that Tregs in colon cancer patients can become proinflammatory and tumor-promoting. These properties were directly linked with their expression of RORγt (retinoic acid-related orphan receptor-γt), the signature transcription factor of T(H)17 cells. We report that Wnt/ß-catenin signaling in T cells promotes expression of RORγt. Expression of ß-catenin was elevated in T cells, including Tregs, of patients with colon cancer. Genetically engineered activation of ß-catenin in mouse T cells resulted in enhanced chromatin accessibility in the proximity of T cell factor-1 (Tcf-1) binding sites genome-wide, induced expression of T(H)17 signature genes including RORγt, and promoted T(H)17-mediated inflammation. Strikingly, the mice had inflammation of small intestine and colon and developed lesions indistinguishable from colitis-induced cancer. Activation of ß-catenin only in Tregs was sufficient to produce inflammation and initiate cancer. On the basis of these findings, we conclude that activation of Wnt/ß-catenin signaling in effector T cells and/or Tregs is causatively linked with the imprinting of proinflammatory properties and the promotion of colon cancer.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Colite/metabolismo , Colo/metabolismo , Neoplasias do Colo/metabolismo , Mediadores da Inflamação/metabolismo , Linfócitos do Interstício Tumoral/metabolismo , beta Catenina/metabolismo , Animais , Sítios de Ligação , Linfócitos T CD4-Positivos/imunologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/imunologia , Transformação Celular Neoplásica/metabolismo , Montagem e Desmontagem da Cromatina , Colite/genética , Colite/imunologia , Colite/patologia , Colo/imunologia , Colo/patologia , Neoplasias do Colo/genética , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Genes APC , Fator 1-alfa Nuclear de Hepatócito , Humanos , Ativação Linfocitária , Linfócitos do Interstício Tumoral/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Fator 1 de Transcrição de Linfócitos T/genética , Fator 1 de Transcrição de Linfócitos T/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Células Th17/imunologia , Células Th17/metabolismo , Via de Sinalização Wnt , beta Catenina/genéticaRESUMO
PURPOSE OF REVIEW: Tumor growth elicits antigen-specific cytotoxic as well as immune suppressive responses. Interleukin-10 (IL-10) is a key immune-suppressive cytokine produced by regulatory T-cells and by helper T-cells. Here, we review pleiotropic functions of IL-10 that impact the immune pathology of cancer. RECENT FINDINGS: The role of IL-10 in cancer has become less certain with the knowledge of its immune stimulatory functions. IL-10 is needed for T-helper cell functions, T-cell immune surveillance, and suppression of cancer-associated inflammation. By promoting tumor-specific immune surveillance and hindering pathogenic inflammation, IL-10 is emerging as a key cytokine in the battle of the host against cancer. SUMMARY: IL-10 functions at the cross-roads of immune stimulation and immune suppression in cancer. Immunological mechanisms of action of IL-10 can be ultimately exploited to develop novel and effective cancer therapies.
Assuntos
Antígenos de Neoplasias/imunologia , Imunomodulação , Interleucina-10/imunologia , Neoplasias/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Animais , Linhagem Celular Tumoral/imunologia , Proliferação de Células , Células Dendríticas/imunologia , Feminino , Humanos , Tolerância Imunológica , Interleucina-10/uso terapêutico , Ativação Linfocitária , Masculino , Camundongos , Neoplasias/patologia , Neoplasias/terapiaRESUMO
Interleukin (IL)-10 is elevated in cancer and is thought to contribute to immune tolerance and tumor growth. Defying these expectations, the adoptive transfer of IL-10-expressing T cells to mice with polyposis attenuates microbial-induced inflammation and suppresses polyposis. To gain better insights into how IL-10 impacts polyposis, we genetically ablated IL-10 in T cells in APC(Δ468) mice and compared the effects of treatment with broad-spectrum antibiotics. We found that T cells and regulatory T cells (Treg) were a major cellular source of IL-10 in both the healthy and polyp-bearing colon. Notably, T cell-specific ablation of IL-10 produced pathologies that were identical to mice with a systemic deficiency in IL-10, in both cases increasing the numbers and growth of colon polyps. Eosinophils were found to densely infiltrate colon polyps, which were enriched similarly for microbiota associated previously with colon cancer. In mice receiving broad-spectrum antibiotics, we observed reductions in microbiota, inflammation, and polyposis. Together, our findings establish that colon polyposis is driven by high densities of microbes that accumulate within polyps and trigger local inflammatory responses. Inflammation, local microbe densities, and polyp growth are suppressed by IL-10 derived specifically from T cells and Tregs.
Assuntos
Pólipos Adenomatosos/etiologia , Linfócitos T CD4-Positivos/imunologia , Neoplasias do Colo/complicações , Inflamação/etiologia , Interleucina-10/fisiologia , Microbiota/imunologia , Linfócitos T Reguladores/imunologia , Pólipos Adenomatosos/patologia , Transferência Adotiva , Animais , Antibacterianos/farmacologia , Linfócitos T CD4-Positivos/metabolismo , Colo/imunologia , Colo/metabolismo , Colo/patologia , Neoplasias do Colo/imunologia , Neoplasias do Colo/microbiologia , Citocinas/metabolismo , DNA Bacteriano/genética , Modelos Animais de Doenças , Imunofluorescência , Tolerância Imunológica , Inflamação/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Regulatory T cells (Tregs) that expand in human colon cancer express retinoid-related orphan receptor γt (RORγt) and exert potent T-cell suppressive functions while mediating pro-inflammatory effects. Similar Tregs expand and drive a vicious cycle of inflammation in murine polyposis. Targeting RORγt in Tregs interrupts such a cycle and protects mice against polyposis, suggesting that a similar intervention may provide therapeutic benefits to colon cancer patients.
RESUMO
PURPOSE: To understand signaling pathways that shape inflamed tissue and predispose to cancer is critical for effective prevention and therapy for chronic inflammatory diseases. We have explored phosphoinositide 3-kinase (PI3K) activity in human inflammatory bowel diseases and mouse colitis models. EXPERIMENTAL DESIGN: We conducted immunostaining of phosphorylated AKT (pAKT) and unbiased high-throughput image acquisition and quantitative analysis of samples of noninflamed normal colon, colitis, dysplasia, and colorectal cancer. Mechanistic insights were gained from ex vivo studies of cell interactions, the piroxicam/IL-10(-/-) mouse model of progressive colitis, and use of the PI3K inhibitor LY294002. RESULTS: Progressive increase in densities of pAKT-positive tumor-associated macrophages (TAM) and increase in densities of mast cells in the colonic submucosa were noted with colitis and progression to dysplasia and cancer. Mast cells recruited macrophages in ex vivo migration assays, and both mast cells and TAMs promoted invasion of cancer cells. Pretreatment of mast cells with LY294002 blocked recruitment of TAMs. LY294002 inhibited mast cell and TAM-mediated tumor invasion, and in mice, blocked stromal PI3K, colitis, and cancer. CONCLUSION: The PI3K/AKT pathway is active in cells infiltrating inflamed human colon tissue. This pathway sustains the recruitment of inflammatory cells through a positive feedback loop. The PI3K/AKT pathway is essential for tumor invasion and the malignant features of the piroxicam/IL-10(-/-) mouse model. LY294002 targets the PI3K pathway and hinders progressive colitis. These findings indicate that colitis and progression to cancer are dependent on stromal PI3K and sensitive to treatment with LY294002.
Assuntos
Colite/imunologia , Neoplasias Colorretais/imunologia , Células Epiteliais/enzimologia , Macrófagos/enzimologia , Mastócitos/enzimologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Anticarcinógenos/farmacologia , Degranulação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Cromonas/farmacologia , Colite/complicações , Colite/tratamento farmacológico , Colite/patologia , Colo/patologia , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/patologia , Neoplasias Colorretais/prevenção & controle , Inibidores de Ciclo-Oxigenase/farmacologia , Avaliação Pré-Clínica de Medicamentos , Células HT29 , Humanos , Mucosa Intestinal/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Morfolinas/farmacologia , Invasividade Neoplásica , Inibidores de Fosfoinositídeo-3 Quinase , Piroxicam/farmacologia , Transdução de Sinais , Triptases/metabolismoRESUMO
In this study, we investigated the use of high-resolution magnetic resonance imaging (MRI) methods for in vivo detection and quantitative characterization of colorectal tumors in the transgenic APC(Δ468) mouse model. High-resolution T(1)-weighted (T(1)W) images, T(2)-weighted (T(2)W) images, and dynamic contrast-enhanced (DCE) measurements were performed using a 7.0 T small-animal imaging system (N = 10). Individual tumors were identified on both T(1)W and T(2)W images. Twenty-eight tumors (2.8 ± 0.9 mm, mean ± SD) were detected with high-resolution MRI across a distance of roughly 3 cm from the rectum to the splenic flexure, whereas 29 tumors were found within corresponding colon tissue samples examined at gross necropsy in the same area. T(2) values were significantly different between tumor, skeletal muscle, and normal intestinal wall tissues (p < .05). For analysis of the vascular characteristics of colon tumor tissues using DCE measurements, the initial area under the curve (IAUC) for Gd contrast concentration curve (time) (C(Gd) [t]) was calculated with integration times of 60 and 120 seconds post-contrast infusion; two integration times were selected to capture both tracer wash-in and wash-out characteristics. IAUC measurements were significantly larger in tumor tissues compared to both normal intestinal wall and skeletal muscle tissues (p < .001). In vivo anatomic and quantitative MRI measurements were readily feasible in the transgenic APC(Δ468) mouse model. These noninvasive methods should improve experimental efficiencies during longitudinal survival studies that otherwise would require single-end-point necropsy measurements.
Assuntos
Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Imageamento por Ressonância Magnética/métodos , Imagem Molecular/métodos , Polipose Adenomatosa do Colo/metabolismo , Animais , Área Sob a Curva , Neoplasias Colorretais/metabolismo , Meios de Contraste/química , Meios de Contraste/farmacocinética , Modelos Animais de Doenças , Gadolínio/química , Gadolínio/farmacocinética , Camundongos , Camundongos TransgênicosRESUMO
Cholesterol is known to modulate the physical properties of cell membranes, but its direct involvement in cellular signaling has not been thoroughly investigated. Here we show that cholesterol specifically binds many PDZ domains found in scaffold proteins, including the N-terminal PDZ domain of NHERF1/EBP50. This modular domain has a cholesterol-binding site topologically distinct from its canonical protein-binding site and serves as a dual-specificity domain that bridges the membrane and juxta-membrane signaling complexes. Disruption of the cholesterol-binding activity of NHERF1 largely abrogates its dynamic co-localization with and activation of cystic fibrosis transmembrane conductance regulator, one of its binding partners in the plasma membrane of mammalian cells. At least seven more PDZ domains from other scaffold proteins also bind cholesterol and have cholesterol-binding sites, suggesting that cholesterol modulates cell signaling through direct interactions with these scaffold proteins. This mechanism may provide an alternative explanation for the formation of signaling platforms in cholesterol-rich membrane domains.
Assuntos
Colesterol/fisiologia , Domínios PDZ/fisiologia , Transdução de Sinais/fisiologia , Sítios de Ligação , Canais de Cloreto/fisiologia , Polarização de Fluorescência , Células HEK293/fisiologia , Humanos , Regiões de Interação com a Matriz/fisiologia , Microscopia Confocal , Imagem Molecular , Fosfoproteínas/fisiologia , Trocadores de Sódio-Hidrogênio/fisiologiaRESUMO
The role of regulatory T cells (T(regs)) in human colon cancer (CC) remains controversial: high densities of tumor-infiltrating T(regs) can correlate with better or worse clinical outcomes depending on the study. In mouse models of cancer, T(regs) have been reported to suppress inflammation and protect the host, suppress T cells and protect the tumor, or even have direct cancer-promoting attributes. These different effects may result from the presence of different T(reg) subsets. We report the preferential expansion of a T(reg) subset in human CC with potent T cell-suppressive, but compromised anti-inflammatory, properties; these cells are distinguished from T(regs) present in healthy donors by their coexpression of Foxp3 and RORγt. T(regs) with similar attributes were found to be expanded in mouse models of hereditary polyposis. Indeed, ablation of the RORγt gene in Foxp3(+) cells in polyp-prone mice stabilized T(reg) anti-inflammatory functions, suppressed inflammation, improved polyp-specific immune surveillance, and severely attenuated polyposis. Ablation of interleukin-6 (IL-6), IL-23, IL-17, or tumor necrosis factor-α in polyp-prone mice reduced polyp number but not to the same extent as loss of RORγt. Surprisingly, loss of IL-17A had a dual effect: IL-17A-deficient mice had fewer polyps but continued to have RORγt(+) T(regs) and developed invasive cancer. Thus, we conclude that RORγt has a central role in determining the balance between protective and pathogenic T(regs) in CC and that T(reg) subtype regulates inflammation, potency of immune surveillance, and severity of disease outcome.
Assuntos
Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Linfócitos T Reguladores/imunologia , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Proliferação de Células , Citocinas/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Humanos , Vigilância Imunológica , Terapia de Imunossupressão , Inflamação/patologia , Pólipos Intestinais/imunologia , Pólipos Intestinais/patologia , Pólipos Intestinais/prevenção & controle , Camundongos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/deficiência , Células Th17/imunologiaRESUMO
An imbalance of commensal bacteria and their gene products underlies mucosal and, in particular, gastrointestinal inflammation and a predisposition to cancer. Lactobacillus species have received considerable attention as examples of beneficial microbiota. We have reported previously that deletion of the phosphoglycerol transferase gene that is responsible for lipoteichoic acid (LTA) biosynthesis in Lactobacillus acidophilus (NCK2025) rendered this bacterium able to significantly protect mice against induced colitis when delivered orally. Here we report that oral treatment with LTA-deficient NCK2025 normalizes innate and adaptive pathogenic immune responses and causes regression of established colonic polyps. This study reveals the proinflammatory role of LTA and the ability of LTA-deficient L. acidophilus to regulate inflammation and protect against colonic polyposis in a unique mouse model.
Assuntos
Polipose Adenomatosa do Colo/imunologia , Lactobacillus acidophilus/genética , Lipopolissacarídeos/genética , Ácidos Teicoicos/genética , Polipose Adenomatosa do Colo/patologia , Animais , Camundongos , Linfócitos T Reguladores/imunologiaRESUMO
Mast cells (MC) are a bone marrow-derived, long-lived, heterogeneous cellular population that function both as positive and negative regulators of immune responses. They are arguably the most productive chemical factory in the body and influence other cells through both soluble mediators and cell-to-cell interaction. MC are commonly seen in various tumors and have been attributed alternatively with tumor rejection or tumor promotion. Tumor-infiltrating MC are derived both from sentinel and recruited progenitor cells. MC can directly influence tumor cell proliferation and invasion but also help tumors indirectly by organizing its microenvironment and modulating immune responses to tumor cells. Best known for orchestrating inflammation and angiogenesis, the role of MC in shaping adaptive immune responses has become a focus of recent investigations. MC mobilize T cells and antigen-presenting dendritic cells. They function as intermediaries in regulatory T cells (Treg)-induced tolerance but can also modify or reverse Treg-suppressive properties. The central role of MC in the control of innate and adaptive immunity endows them with the ability to tune the nature of host responses to cancer and ultimately influence the outcome of disease and fate of the cancer patient.
Assuntos
Mastócitos/patologia , Neoplasias/patologia , Animais , Apresentação de Antígeno/imunologia , Modelos Animais de Doenças , Humanos , Imunidade Celular , Mastócitos/imunologia , Camundongos , Invasividade Neoplásica/imunologia , Neoplasias/diagnóstico , Neoplasias/imunologia , Prognóstico , Linfócitos T Reguladores/imunologiaRESUMO
Arachidonic acid metabolism has been implicated in colon carcinogenesis, but the role of hematopoietic 5-lipoxygenase (5LO) that may impact tumor immunity in development of colon cancer has not been explored. Here we show that tissue-specific deletion of the 5LO gene in hematopoietic cells profoundly attenuates polyp development in the APC(Δ468) murine model of colon polyposis. In vitro analyses indicated that mast cells in particular utilized 5LO to limit proliferation of intestinal epithelial cells and to mobilize myeloid-derived suppressor cells (MDSCs). Mice lacking hemapoietic expression of 5LO exhibited reduced recruitment of MDSCs to the spleen, mesenteric lymph nodes, and primary tumor site. 5LO deficiency also reduced the activity in MDSCs of arginase-1, which is thought to be critical for MDSC function. Together, our results establish a pro-tumorigenic role of hematopoietic 5LO in the immune microenvironment and suggest 5LO inhibition as an avenue for future investigation in treatment of colorectal polyposis and cancer.
Assuntos
Araquidonato 5-Lipoxigenase/metabolismo , Polipose Intestinal/enzimologia , Polipose Intestinal/genética , Mastócitos/enzimologia , Animais , Separação Celular , Citometria de Fluxo , Imunofluorescência , Genes APC , Polipose Intestinal/patologia , Camundongos , Camundongos MutantesRESUMO
T-regulatory cells (Treg) and mast cells (MC) are abundant in colorectal cancer (CRC) tumors. Interaction between the two is known to promote immune suppression or loss of Treg functions and autoimmunity. Here, we demonstrate that in both human CRC and murine polyposis the outcome of this interaction is the generation of potently immune suppressive but proinflammatory Treg (DeltaTreg). These Treg shut down IL10, gain potential to express IL17, and switch from suppressing to promoting MC expansion and degranulation. This change is also brought about by direct coculture of MC and Treg, or culture of Treg in medium containing IL6 and IL2. IL6 deficiency in the bone marrow of mice susceptible to polyposis eliminated IL17 production by the polyp infiltrating Treg, but did not significantly affect the growth of polyps or the generation of proinflammatory Treg. IL6-deficient MC could generate proinflammatory Treg. Thus, MC induce Treg to switch function and escalate inflammation in CRC without losing T-cell-suppressive properties. IL6 and IL17 are not needed in this process.
Assuntos
Neoplasias Colorretais/imunologia , Mastócitos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Técnicas de Cocultura , Humanos , Interleucinas/deficiência , Interleucinas/imunologia , Camundongos , Camundongos Knockout , Linfócitos T Auxiliares-Indutores/imunologiaRESUMO
BACKGROUND & AIMS: Mesalamine is a mainstay therapeutic agent in chronic ulcerative colitis (CUC) in which condition it reverses crypt architectural changes and reduces colitis-associated cancer (CAC). The present study addressed the possibility that mesalamine reduces beta-catenin-associated progenitor cell activation, Akt-phosphorylated beta-catenin(Ser552) (P-beta-catenin), and colitis-induced dysplasia (CID). METHODS: Effects of mesalamine on P-beta-catenin staining and function were assessed by immunohistochemistry and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) in biopsy specimens of CUC in mild or "refractory" severe mucosal inflammation. Effects of mesalamine on epithelial proliferation and activation of Akt and beta-catenin were assessed in interleukin (IL)-10(-/-) colitis and CID by immunohistochemistry and Western blotting. Dysplasia was assessed by counting the number and lengths of lesions per colon. RESULTS: Data from IL-10(-/-) and human colitis samples show that mesalamine reduced Akt activation and P-beta-catenin levels in the middle and upper crypt. Reductions in P-beta-catenin in CUC biopsy specimens with severe inflammation suggested that mesalamine reduced P-beta-catenin levels in tissue refractory to mesalamine's anti-inflammatory effects. In IL-10(-/-) mice, mesalamine reduced CID concordant with inhibition of crypt Akt and beta-catenin signaling. CONCLUSIONS: The results are consistent with the model that mesalamine contributes to chemoprevention in CAC by reducing beta-catenin signaling within intestinal progenitors.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Colite Ulcerativa/metabolismo , Colo/metabolismo , Células Epiteliais/metabolismo , Mesalamina/farmacologia , beta Catenina/metabolismo , Animais , Biópsia , Proliferação de Células/efeitos dos fármacos , Colite Ulcerativa/patologia , Colo/efeitos dos fármacos , Colo/patologia , Modelos Animais de Doenças , Progressão da Doença , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Humanos , Interleucina-10/genética , Interleucina-10/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
T-regulatory (Treg) cells play a major role in cancer by suppressing protective antitumor immune responses. A series of observations (from a single laboratory) suggest that Treg cells are protective in cancer by virtue of their ability to control cancer-associated inflammation in an interleukin (IL)-10-dependent manner. Here, we report that the ability of Treg cells to produce IL-10 and control inflammation is lost in the course of progressive disease in a mouse model of hereditary colon cancer. Treg cells that expand in adenomatous polyps no longer produce IL-10 and instead switch to production of IL-17. Aberrant Treg cells from polyp-ridden mice promote rather than suppress focal mastocytosis, a critical tumor-promoting inflammatory response. The cells, however, maintain other Treg characteristics, including their inability to produce IL-2 and ability to suppress proliferation of stimulated CD4 T cells. By promoting inflammation and suppressing T-helper functions, these cells act as a double-edged knife propagating tumor growth.
Assuntos
Polipose Adenomatosa do Colo/complicações , Polipose Adenomatosa do Colo/imunologia , Inflamação/imunologia , Neoplasias/imunologia , Linfócitos T Reguladores/imunologia , Linfócitos T/imunologia , Transferência Adotiva , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Interleucina-10/fisiologia , Interleucina-17/biossíntese , Ativação Linfocitária , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/patologia , Fenótipo , Células-Tronco/imunologiaRESUMO
KIF16B is a newly identified kinesin that regulates the intracellular motility of early endosomes. KIF16B is unique among kinesins in that its cargo binding is mediated primarily by the strong interaction of its PX domain with endosomal lipids. To elucidate the structural basis of this unique endosomal anchoring activity of KIF16B-PX, we determined the crystal structure of the PX domain and performed in vitro and cellular membrane binding measurements for KIF16B-PX and mutants. The most salient structural feature of KIF16B-PX is that two neighboring residues, L1248 and F1249, on the membrane-binding surface form a protruding hydrophobic stalk with a large solvent-accessible surface area. This unique structure, arising from the complementary stacking of the two side chains and the local conformation, allows strong hydrophobic membrane interactions and endosome tethering. The presence of similar hydrophobic pairs in the amino-acid sequences of other membrane-binding domains and proteins suggests that the same structural motif may be shared by other membrane-binding proteins, whose physiological functions depend on strong hydrophobic membrane interactions.