scholarly journals Modulation of Tumor-Associated Macrophages (TAM) Phenotype by Platelet-Activating Factor (PAF) Receptor

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ildefonso Alves da Silva Junior ◽  
Simone Cardozo Stone ◽  
Renata Marques Rossetti ◽  
Sonia Jancar ◽  
Ana Paula Lepique
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Biological Effects ◽  
Platelet Activating Factor ◽  
Host Cells ◽  
Leukocyte Infiltration ◽  
Wild Type ◽  
B16f10 Melanoma ◽  
Paf Receptor

Platelet-activating factor (PAF) plays an important role in the pathogenesis of several types of tumors. The biological effects of PAF are mediated by the PAF receptor (PAFR), which can be expressed by tumor cells and host cells that infiltrate the tumor microenvironment. In the present study, we investigated the role of PAFR expressed by leukocytes that infiltrate two types of tumors, one that expresses PAFR (TC-1 carcinoma) and another that does not express the receptor (B16F10 melanoma) implanted in mice that express the receptor or not (PAFR KO). It was found that both tumors grew significantly less in PAFR KO than inwild-type(WT) mice. Analysis of the leukocyte infiltration shown in PAFR KO increased the frequency of neutrophils (Gr1+) and of CD8+lymphocytes in B16F10 tumors and of CD4+lymphocytes in TC-1 tumors. PAFR KO also had a higher frequency of M1-like (CD11c+) and lower M2-like (CD206+) macrophages infiltrated in both tumors. This was confirmed in macrophages isolated from the tumors that showed higher iNOS, lower arginase activity, and lower IL10 expression in PAFR KO tumors than WT mice. These data suggest that in the tumor microenvironment, endogenous PAF-like activity molecules bind PAFR in macrophages which acquire an M2-like profile and this promotes tumor growth.

scholarly journals The Role of Chemoattractant Receptors in Shaping the Tumor Microenvironment

2014 ◽  
Vol 2014 ◽  
pp. 1-33 ◽  
Author(s):  
Jiamin Zhou ◽  
Yi Xiang ◽  
Teizo Yoshimura ◽  
Keqiang Chen ◽  
Wanghua Gong ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Immune Responses ◽  
Tumor Cells ◽  
Immune Cells ◽  
Malignant Tumors ◽  
G Protein Coupled Receptors ◽  
Host Cells ◽  
The Past ◽  
G Protein Coupled

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.

scholarly journals Lack of Platelet-Activating Factor Receptor Attenuates Experimental Food Allergy but Not Its Metabolic Alterations regarding Adipokine Levels

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Nathália Vieira Batista ◽  
Roberta Cristelli Fonseca ◽  
Denise Perez ◽  
Rafaela Vaz Sousa Pereira ◽  
Juliana de Lima Alves ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Food Allergy ◽  
Inflammatory Process ◽  
Platelet Activating Factor ◽  
Oral Challenge ◽  
Tissue Loss ◽  
Lack Of Information ◽  
Paf Receptor ◽  
Rolling Leukocytes

Platelet-activating factor (PAF) is known to be an important mediator of anaphylaxis. However, there is a lack of information in the literature about the role of PAF in food allergy. The aim of this work was to elucidate the participation of PAF during food allergy development and the consequent adipose tissue inflammation along with its alterations. Our data demonstrated that, both before oral challenge and after 7 days receiving ovalbumin (OVA) diet, OVA-sensitized mice lacking the PAF receptor (PAFR) showed a decreased level of anti-OVA IgE associated with attenuated allergic markers in comparison to wild type (WT) mice. Moreover, there was less body weight and adipose tissue loss in PAFR-deficient mice. However, some features of inflamed adipose tissue presented by sensitized PAFR-deficient and WT mice after oral challenge were similar, such as a higher rate of rolling leukocytes in this tissue and lower circulating levels of adipokines (resistin and adiponectin) in comparison to nonsensitized mice. Therefore, PAF signaling through PAFR is important for the allergic response to OVA but not for the adipokine alterations caused by this inflammatory process. Our work clarifies some effects of PAF during food allergy along with its role on the metabolic consequences of this inflammatory process.

scholarly journals A reassessment of the role of B7-1 expression in tumor rejection.

1995 ◽  
Vol 182 (5) ◽  
pp. 1415-1421 ◽  
Author(s):  
T C Wu ◽  
A Y Huang ◽  
E M Jaffee ◽  
H I Levitsky ◽  
D M Pardoll
Keyword(s):  
T Cells ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Tumor Rejection ◽  
Type B ◽  
Wild Type ◽  
Systemic Immunity ◽  
Murine Tumor

Introduction of the B7-1 gene into murine tumor cells can result in rejection of the B7-1 transductants and, in some cases, systemic immunity to subsequent challenge with the nontransduced tumor cells. These effects have been largely attributed to the function of B7-1 as a costimulator in directly activating tumor specific, major histocompatibility class I-restricted CD8+ T cells. We examined the role of B7-1 expression in the direct rejection as well as in the induction of systemic immunity to a nonimmunogenic murine tumor. B-16 melanoma cells with high levels of B7-1 expression did not grow in C57BL/6 recipient mice, while wild-type B-16 cells and cells with low B7-1 expression grew progressively within 21 d. In mixing experiments with B7-1hi and wild-type B-16 cells, tumors grew out in vivo even when a minority of cells were B7-1-. Furthermore, the occasional tumors that grew out after injection of 100% B-16 B7-1hi cells showed markedly decreased B7-1 expression. In vivo antibody depletions showed that NK1.1 and CD8+ T cells, but not CD4+ T cells, were essential for the in vivo rejection of tumors. Animals that rejected B-16 B7-1hi tumors did not develop enhanced systemic immunity against challenge with wild-type B-16 cells. These results suggest that a major role of B7-1 expression by tumors is to mediate direct recognition and killing by natural killer cells. With an intrinsically nonimmunogenic tumor, this direct killing does not lead to enhanced systemic immunity.

scholarly journals CCL2: An Important Mediator Between Tumor Cells and Host Cells in Tumor Microenvironment

2021 ◽  
Vol 11 ◽  
Author(s):  
Jiakang Jin ◽  
Jinti Lin ◽  
Ankai Xu ◽  
Jianan Lou ◽  
Chao Qian ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cell Types ◽  
Host Cells ◽  
Specific Cell ◽  
Tumor Patients ◽  
Multiple Tumor ◽  
Inflammatory Monocytes ◽  
Immunosuppressive Cell ◽  
Tumor Types

Tumor microenvironment (TME) formation is a major cause of immunosuppression. The TME consists of a considerable number of macrophages and stromal cells that have been identified in multiple tumor types. CCL2 is the strongest chemoattractant involved in macrophage recruitment and a powerful initiator of inflammation. Evidence indicates that CCL2 can attract other host cells in the TME and direct their differentiation in cooperation with other cytokines. Overall, CCL2 has an unfavorable effect on prognosis in tumor patients because of the accumulation of immunosuppressive cell subtypes. However, there is also evidence demonstrating that CCL2 enhances the anti-tumor capability of specific cell types such as inflammatory monocytes and neutrophils. The inflammation state of the tumor seems to have a bi-lateral role in tumor progression. Here, we review works focusing on the interactions between cancer cells and host cells, and on the biological role of CCL2 in these processes.

scholarly journals Hypoxia-inducible factor (HIF): fuel for cancer progression

2021 ◽  
Vol 14 ◽  
Author(s):  
Saurabh Satija ◽  
Harpreet Kaur ◽  
Murtaza M. Tambuwala ◽  
Prabal Sharma ◽  
Manish Vyas ◽  
...  
Keyword(s):  
Biological Sciences ◽  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Cancer Progression ◽  
Oxygen Deficiency ◽  
Hypoxia Inducible Factor ◽  
Transcription Factor Activation ◽  
Underlying Mechanisms ◽  
Adaptive Reactions

Hypoxia is an integral part of tumor microenvironment, caused primarily due to rapidly multiplying tumor cells and a lack of proper blood supply. Among the major hypoxic pathways, HIF-1 transcription factor activation is one of the widely investigated pathways in the hypoxic tumor microenvironment (TME). HIF-1 is known to activate several adaptive reactions in response to oxygen deficiency in tumor cells. HIF-1 has two subunits, HIF-1β (constitutive) and HIF-1α (inducible). The HIF-1α expression is largely regulated via various cytokines (through PI3K-ACT-mTOR signals), which involves the cascading of several growth factors and oncogenic cascades. These events lead to the loss of cellular tumor suppressant activity through changes in the level of oxygen via oxygen-dependent and oxygen-independent pathways. The significant and crucial role of HIF in cancer progression and its underlying mechanisms have gained much attention lately among the translational researchers in the fields of cancer and biological sciences, which have enabled them to correlate these mchanisms with various other disease modalities. In the present review, we have summarized the key findings related to the role of HIF in the progression of tumors.

Role of the β1-integrin cytoplasmic tail in mediating invasin-promoted internalization of Yersinia

2002 ◽  
Vol 115 (13) ◽  
pp. 2669-2678 ◽  
Author(s):  
Anna Gustavsson ◽  
Annika Armulik ◽  
Cord Brakebusch ◽  
Reinhard Fässler ◽  
Staffan Johansson ◽  
...  
Keyword(s):  
Marked Reduction ◽  
Yersinia Pseudotuberculosis ◽  
Host Cells ◽  
Β1 Integrin ◽  
Complex Structures ◽  
Wild Type ◽  
Similar Reduction ◽  
Focal Complex ◽  
Β1 Integrins

Invasin of Yersinia pseudotuberculosis binds to β1-integrins on host cells and triggers internalization of the bacterium. To elucidate the mechanism behind the β1-integrin-mediated internalization of Yersinia, a β1-integrin-deficient cell line, GD25, transfected with wild-type β1A, β1B or different mutants of the β1A subunit was used. Both β1A and β1B bound to invasin-expressing bacteria, but only β1A was able to mediate internalization of the bacteria. The cytoplasmic region of β1A, differing from β1B, contains two NPXY motifs surrounding a double threonine site. Exchanging the tyrosines of the two NPXYs to phenylalanines did not inhibit the uptake, whereas a marked reduction was seen when the first tyrosine (Y783) was exchanged to alanine. A similar reduction was seen when the two nearby threonines (TT788-9) were exchanged with alanines. It was also noted that cells affected in bacterial internalization exhibited reduced spreading capability when seeded onto invasin, suggesting a correlation between the internalization of invasin-expressing bacteria and invasin-induced spreading. Likewise, integrins defective in forming peripheral focal complex structures was unable to mediate uptake of invasin-expressing bacteria.

scholarly journals Interleukin-1-induced leukocyte extravasation across rat mesenteric microvessels is mediated by platelet-activating factor

Blood ◽  
1995 ◽  
Vol 85 (9) ◽  
pp. 2553-2558 ◽  
Author(s):  
S Nourshargh ◽  
SW Larkin ◽  
A Das ◽  
TJ Williams
Keyword(s):  
Vessel Wall ◽  
Interleukin 1 ◽  
Platelet Activating Factor ◽  
Micron Diameter ◽  
Paf Receptor ◽  
Leukocyte Extravasation ◽  
Mesenteric Microvessels ◽  
Adherent Leukocytes

Although our understanding of the molecular interactions that mediate the adhesion of leukocytes to venular endothelial cells has greatly expanded, very little is known about the mechanisms that mediate the passage of leukocytes across the vessel wall in vivo. The aim of the present study was to investigate the role of endogenously formed platelet-activating factor (PAF) in the process of leukocyte extravasation induced by interleukin-1 (IL-1). To determine at which stage of emigration PAF was involved, we studied the behavior of leukocytes within rat mesenteric microvessels by intravital microscopy. Rats were injected intraperitoneally with saline, recombinant rat IL-1 beta (IL-1 beta), or the peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) 4 hours before the exteriorization of the mesenteric tissue. In animals treated with IL-1 beta there was a significant increase in the number of rolling and adherent leukocytes within venules (20- to 40-micron diameter) and in the number of extravasated leukocytes in the tissue. Pretreatment of rats with the PAF receptor antagonist UK-74,505 had no effect on the leukocyte responses of rolling and adhesion, but significantly inhibited the migration of the leukocytes across the vessel wall induced by IL-1 beta (76% inhibition). A structurally unrelated PAF antagonist, WEB-2170, produced the same effect (64% inhibition). However, in contrast, UK-74,505 had no effect on the leukocyte extravasation induced by FMLP, indicating selectivity for the response elicited by certain mediators. These results provide the first line of direct evidence for the involvement of endogenously formed PAF in the process of leukocyte extravasation induced by IL-1 in vivo.

scholarly journals Fluorescence-Reported Allelic Exchange Mutagenesis-Mediated Gene Deletion Indicates a Requirement for Chlamydia trachomatis Tarp during In Vivo Infectivity and Reveals a Specific Role for the C Terminus during Cellular Invasion

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Susmita Ghosh ◽  
Elizabeth A. Ruelke ◽  
Joshua C. Ferrell ◽  
Maria D. Bodero ◽  
Kenneth A. Fields ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Host Cells ◽  
Actin Binding ◽  
Wild Type ◽  
Content Type ◽  
Allelic Exchange ◽  
Binding Domains

ABSTRACT The translocated actin recruiting phosphoprotein (Tarp) is a multidomain type III secreted effector used by Chlamydia trachomatis. In aggregate, existing data suggest a role of this effector in initiating new infections. As new genetic tools began to emerge to study chlamydial genes in vivo, we speculated as to what degree Tarp function contributes to Chlamydia’s ability to parasitize mammalian host cells. To address this question, we generated a complete tarP deletion mutant using the fluorescence-reported allelic exchange mutagenesis (FRAEM) technique and complemented the mutant in trans with wild-type tarP or mutant tarP alleles engineered to harbor in-frame domain deletions. We provide evidence for the significant role of Tarp in C. trachomatis invasion of host cells. Complementation studies indicate that the C-terminal filamentous actin (F-actin)-binding domains are responsible for Tarp-mediated invasion efficiency. Wild-type C. trachomatis entry into HeLa cells resulted in host cell shape changes, whereas the tarP mutant did not. Finally, using a novel cis complementation approach, C. trachomatis lacking tarP demonstrated significant attenuation in a murine genital tract infection model. Together, these data provide definitive genetic evidence for the critical role of the Tarp F-actin-binding domains in host cell invasion and for the Tarp effector as a bona fide C. trachomatis virulence factor.

scholarly journals The Roles of Stroma-Derived Chemokine in Different Stages of Cancer Metastases

2020 ◽  
Vol 11 ◽  
Author(s):  
Shahid Hussain ◽  
Bo Peng ◽  
Mathew Cherian ◽  
Jonathan W. Song ◽  
Dinesh K. Ahirwar ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Cancer Progression ◽  
Tumor Development ◽  
Inflammatory Cells ◽  
Host Cells ◽  
Metastatic Niche ◽  
Cancer Pathogenesis ◽  
Cancer Metastases ◽  
Cellular Components

The intricate interplay between malignant cells and host cellular and non-cellular components play crucial role in different stages of tumor development, progression, and metastases. Tumor and stromal cells communicate to each other through receptors such as integrins and secretion of signaling molecules like growth factors, cytokines, chemokines and inflammatory mediators. Chemokines mediated signaling pathways have emerged as major mechanisms underlying multifaceted roles played by host cells during tumor progression. In response to tumor stimuli, host cells-derived chemokines further activates signaling cascades that support the ability of tumor cells to invade surrounding basement membrane and extra-cellular matrix. The host-derived chemokines act on endothelial cells to increase their permeability and facilitate tumor cells intravasation and extravasation. The tumor cells-host neutrophils interaction within the vasculature initiates chemokines driven recruitment of inflammatory cells that protects circulatory tumor cells from immune attack. Chemokines secreted by tumor cells and stromal immune and non-immune cells within the tumor microenvironment enter the circulation and are responsible for formation of a “pre-metastatic niche” like a “soil” in distant organs whereby circulating tumor cells “seed’ and colonize, leading to formation of metastatic foci. Given the importance of host derived chemokines in cancer progression and metastases several drugs like Mogamulizumab, Plerixafor, Repertaxin among others are part of ongoing clinical trial which target chemokines and their receptors against cancer pathogenesis. In this review, we focus on recent advances in understanding the complexity of chemokines network in tumor microenvironment, with an emphasis on chemokines secreted from host cells. We especially summarize the role of host-derived chemokines in different stages of metastases, including invasion, dissemination, migration into the vasculature, and seeding into the pre-metastatic niche. We finally provide a brief description of prospective drugs that target chemokines in different clinical trials against cancer.

scholarly journals Inflammatory Cells in Diffuse Large B Cell Lymphoma

2020 ◽  
Vol 9 (8) ◽  
pp. 2418
Author(s):  
Roberto Tamma ◽  
Girolamo Ranieri ◽  
Giuseppe Ingravallo ◽  
Tiziana Annese ◽  
Angela Oranger ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
B Cell ◽  
Tumor Cells ◽  
Immune Cells ◽  
Tumor Antigens ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Diffuse large B cell lymphoma (DLBCL), known as the most common non-Hodgkin lymphoma (NHL) subtype, is characterized by high clinical and biological heterogeneity. The tumor microenvironment (TME), in which the tumor cells reside, is crucial in the regulation of tumor initiation, progression, and metastasis, but it also has profound effects on therapeutic efficacy. The role of immune cells during DLBCL development is complex and involves reciprocal interactions between tumor cells, adaptive and innate immune cells, their soluble mediators and structural components present in the tumor microenvironment. Different immune cells are recruited into the tumor microenvironment and exert distinct effects on tumor progression and therapeutic outcomes. In this review, we focused on the role of macrophages, Neutrophils, T cells, natural killer cells and dendritic cells in the DLBCL microenvironment and their implication as target for DLBCL treatment. These new therapies, carried out by the induction of adaptive immunity through vaccination or passive of immunologic effectors delivery, enhance the ability of the immune system to react against the tumor antigens inducing the destruction of tumor cells.

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