scholarly journals Intratumoral platelet aggregate formation in a murine preclinical glioma model depends on podoplanin expression on tumor cells

2019 ◽  
Vol 3 (7) ◽  
pp. 1092-1102 ◽  
Author(s):  
Barbara Costa ◽  
Tanja Eisemann ◽  
Jens Strelau ◽  
Ingrid Spaan ◽  
Andrey Korshunov ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Tumor Cells ◽  
Cell Types ◽  
Platelet Receptor ◽  
Increased Risk ◽  
Platelet Aggregates ◽  
Glioma Model ◽  
Novel Strategy

Abstract Binding of the sialomucin-like transmembrane glycoprotein podoplanin (PDPN) to the platelet receptor C-type lectin-like receptor 2 induces platelet activation and aggregation. In human high-grade gliomas, PDPN is highly expressed both in tumor cells and in tumor-associated astrocytes. In glioma patients, high expression of PDPN is associated with worse prognosis and has been shown to correlate with intratumoral platelet aggregation and an increased risk of venous thromboembolism (VTE). To functionally assess the role of PDPN in platelet aggregation in vivo, we established a syngeneic orthotopic murine glioma model in C57/Bl6 mice, based on transplantation of p53- and Pten-deficient neural stem cells. This model is characterized by the presence of intratumoral platelet aggregates and by the upregulation of PDPN both in glioma cells and in astrocytes, reflecting the characteristics of human gliomas. Deletion of PDPN either in tumor cells or in astrocytes resulted in glioma formation with similar penetrance and grade compared with control mice. Importantly, only the lack of PDPN in tumor cells, but not in astrocytes, caused a significant reduction in intratumoral platelet aggregates, whereas in vitro, both cell types have similar platelet aggregation-inducing capacities. Our results demonstrate a causative link between PDPN and platelet aggregation in gliomas and pinpoint the tumor cells as the major players in PDPN-induced platelet aggregation. Our data indicate that blocking PDPN specifically on tumor cells could represent a novel strategy to prevent platelet aggregation and thereby reduce the risk of VTE in glioma patients.

Accumulation of Macromolecular Particles in the Reticuloendothelial System (RES) Mediated by Platelet Aggregation and Disaggregation

1969 ◽  
Vol 22 (03) ◽  
pp. 496-507 ◽  
Author(s):  
W.G van Aken ◽  
J Vreeken
Keyword(s):  
Platelet Aggregation ◽  
Degradation Products ◽  
Reticuloendothelial System ◽  
Caproic Acid ◽  
Carbon Particles ◽  
Carbon Clearance ◽  
Aggregation And Disaggregation ◽  
Platelet Aggregates

SummaryCarbon particles cause platelet aggregation in vitro and in vivo. Prior studies established that substances which modify thrombocyte aggregation also influence the rate at which carbon is cleared from the blood.This study was performed in order to elucidate the mechanism by which the carbon-platelet aggregates specifically accumulate in the RES.Activation of fibrinolysis by urokinase or streptokinase reduced the carbon clearance rate, probably due to generated fibrinogen degradation products (FDP). Isolated FDP decreased the carbon clearance and caused disaggregation of platelets and particles in vitro. Inhibition of fibrinolysis by epsilon-amino-caproic acid (EACA), initially accelerated the disappearance of carbon and caused particle accumulation outside the RES, predominantly in the lungs. It is supposed that platelet aggregation and locally activated fibrinolysis act together in the clearance of particles. In the normal situation the RES with its well known low fibrinolytic activity, becomes the receptor of the particles.

scholarly journals Assessment of phagocytic activity in live macrophages-tumor cells co-cultures by Confocal and Nomarski Microscopy

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Dalia Martinez-Marin ◽  
Courtney Jarvis ◽  
Thomas Nelius ◽  
Stéphanie Filleur
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Cells ◽  
Phagocytic Activity ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Functional Assay ◽  
Loss Of Function ◽  
Multiple Cancer

Abstract Macrophages have been recognized as the main inflammatory component of the tumor microenvironment. Although often considered as beneficial for tumor growth and disease progression, tumor-associated macrophages have also been shown to be detrimental to the tumor depending on the tumor microenvironment. Therefore, understanding the molecular interactions between macrophages and tumor cells in relation to macrophages functional activities such as phagocytosis is critical for a better comprehension of their tumor-modulating action. Still, the characterization of these molecular mechanisms in vivo remains complicated due to the extraordinary complexity of the tumor microenvironment and the broad range of tumor-associated macrophage functions. Thus, there is an increasing demand for in vitro methodologies to study the role of cell–cell interactions in the tumor microenvironment. In the present study, we have developed live co-cultures of macrophages and human prostate tumor cells to assess the phagocytic activity of macrophages using a combination of Confocal and Nomarski Microscopy. Using this model, we have emphasized that this is a sensitive, measurable, and highly reproducible functional assay. We have also highlighted that this assay can be applied to multiple cancer cell types and used as a selection tool for a variety of different types of phagocytosis agonists. Finally, combining with other studies such as gain/loss of function or signaling studies remains possible. A better understanding of the interactions between tumor cells and macrophages may lead to the identification of new therapeutic targets against cancer.

scholarly journals Induction of Apoptosis of Metastatic Mammary Carcinoma Cells In Vivo by Disruption of Tumor Cell Surface CD44 Function

1997 ◽  
Vol 186 (12) ◽  
pp. 1985-1996 ◽  
Author(s):  
Qin Yu ◽  
Bryan P. Toole ◽  
Ivan Stamenkovic
Keyword(s):  
Cell Surface ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Lung Tissue ◽  
Mammary Carcinoma ◽  
Cell Types ◽  
Pulmonary Endothelium ◽  
Soluble Cd44

To understand how the hyaluronan receptor CD44 regulates tumor metastasis, the murine mammary carcinoma TA3/St, which constitutively expresses cell surface CD44, was transfected with cDNAs encoding soluble isoforms of CD44 and the transfectants (TA3sCD44) were compared with parental cells (transfected with expression vector only) for growth in vivo and in vitro. Local release of soluble CD44 by the transfectants inhibited the ability of endogenous cell surface CD44 to bind and internalize hyaluronan and to mediate TA3 cell invasion of hyaluronan-producing cell monolayers. Mice intravenously injected with parental TA3/St cells developed massive pulmonary metastases within 21–28 d, whereas animals injected with TA3sCD44 cells developed few or no tumors. Tracing of labeled parental and transfectant tumor cells revealed that both cell types initially adhered to pulmonary endothelium and penetrated the interstitial stroma. However, although parental cells were dividing and forming clusters within lung tissue 48 h following injection, >80% of TA3sCD44 cells underwent apoptosis. Although sCD44 transfectants displayed a marked reduction in their ability to internalize and degrade hyaluronan, they elicited abundant local hyaluronan production within invaded lung tissue, comparable to that induced by parental cells. These observations provide direct evidence that cell surface CD44 function promotes tumor cell survival in invaded tissue and that its suppression can induce apoptosis of the invading tumor cells, possibly as a result of impairing their ability to penetrate the host tissue hyaluronan barrier.

scholarly journals Tumor quiescence: elevating SOX2 in diverse tumor cell types downregulates a broad spectrum of the cell cycle machinery and inhibits tumor growth

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ethan P. Metz ◽  
Erin L. Wuebben ◽  
Phillip J. Wilder ◽  
Jesse L. Cox ◽  
Kaustubh Datta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cell Cycle Machinery

Abstract Background Quiescent tumor cells pose a major clinical challenge due to their ability to resist conventional chemotherapies and to drive tumor recurrence. Understanding the molecular mechanisms that promote quiescence of tumor cells could help identify therapies to eliminate these cells. Significantly, recent studies have determined that the function of SOX2 in cancer cells is highly dose dependent. Specifically, SOX2 levels in tumor cells are optimized to promote tumor growth: knocking down or elevating SOX2 inhibits proliferation. Furthermore, recent studies have shown that quiescent tumor cells express higher levels of SOX2 compared to adjacent proliferating cells. Currently, the mechanisms through which elevated levels of SOX2 restrict tumor cell proliferation have not been characterized. Methods To understand how elevated levels of SOX2 restrict the proliferation of tumor cells, we engineered diverse types of tumor cells for inducible overexpression of SOX2. Using these cells, we examined the effects of elevating SOX2 on their proliferation, both in vitro and in vivo. In addition, we examined how elevating SOX2 influences their expression of cyclins, cyclin-dependent kinases (CDKs), and p27Kip1. Results Elevating SOX2 in diverse tumor cell types led to growth inhibition in vitro. Significantly, elevating SOX2 in vivo in pancreatic ductal adenocarcinoma, medulloblastoma, and prostate cancer cells induced a reversible state of tumor growth arrest. In all three tumor types, elevation of SOX2 in vivo quickly halted tumor growth. Remarkably, tumor growth resumed rapidly when SOX2 returned to endogenous levels. We also determined that elevation of SOX2 in six tumor cell lines decreased the levels of cyclins and CDKs that control each phase of the cell cycle, while upregulating p27Kip1. Conclusions Our findings indicate that elevating SOX2 above endogenous levels in a diverse set of tumor cell types leads to growth inhibition both in vitro and in vivo. Moreover, our findings indicate that SOX2 can function as a master regulator by controlling the expression of a broad spectrum of cell cycle machinery. Importantly, our SOX2-inducible tumor studies provide a novel model system for investigating the molecular mechanisms by which elevated levels of SOX2 restrict cell proliferation and tumor growth.

scholarly journals Involvement of leukocyte function-associated antigen-1 (LFA-1) in the invasion of hepatocyte cultures by lymphoma and T-cell hybridoma cells.

1987 ◽  
Vol 105 (1) ◽  
pp. 553-559 ◽  
Author(s):  
E Roos ◽  
F F Roossien
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
Cell Types ◽  
Hybridoma Cells ◽  
Lymphoma Cells ◽  
Hepatocyte Cultures ◽  
Leukocyte Function ◽  
Vitro Model

We studied the interaction of MB6A lymphoma and TAM2D2 T cell hybridoma cells with hepatocyte cultures as an in vitro model for in vivo liver invasion by these tumor cells. A monoclonal antibody against leukocyte function-associated antigen-1 (LFA-1) inhibited adhesion of the tumor cells to the surface of hepatocytes and consequently strongly reduced invasion. This effect was specific since control antibodies, directed against Thy.1 and against T200, of the same isotype, similar affinity, and comparable binding to these cells, did not inhibit adhesion. This suggests that LFA-1 is involved in the formation of liver metastases by lymphoma cells. TAM2D2 T cell hybridoma cells were agglutinated by anti-LFA-1, but not by control antibodies. Reduction of adhesion was not due to this agglutination since monovalent Fab fragments inhibited adhesion as well, inhibition was also seen under conditions where agglutination was minimal, and anti-LFA-1 similarly affected adhesion of MB6A lymphoma cells that were not agglutinated. The two cell types differed in LFA-1 surface density. TAM2D2 cells exhibited 400,000 surface LFA-1 molecules, 10 times more than MB6A cells. Nevertheless, the level of adhesion and the extent of inhibition by the anti-LFA-1 antibody were only slightly larger for the TAM2D2 cells.

scholarly journals Perfused Platforms to Mimic Bone Microenvironment at the Macro/Milli/Microscale: Pros and Cons

2022 ◽  
Vol 9 ◽  
Author(s):  
Maria Veronica Lipreri ◽  
Nicola Baldini ◽  
Gabriela Graziani ◽  
Sofia Avnet
Keyword(s):  
Extracellular Matrix ◽  
Bone Structure ◽  
Dynamic Network ◽  
Cell Types ◽  
New Drugs ◽  
Culture Methods ◽  
Increased Risk ◽  
Multiple Cell

As life expectancy increases, the population experiences progressive ageing. Ageing, in turn, is connected to an increase in bone-related diseases (i.e., osteoporosis and increased risk of fractures). Hence, the search for new approaches to study the occurrence of bone-related diseases and to develop new drugs for their prevention and treatment becomes more pressing. However, to date, a reliable in vitro model that can fully recapitulate the characteristics of bone tissue, either in physiological or altered conditions, is not available. Indeed, current methods for modelling normal and pathological bone are poor predictors of treatment outcomes in humans, as they fail to mimic the in vivo cellular microenvironment and tissue complexity. Bone, in fact, is a dynamic network including differently specialized cells and the extracellular matrix, constantly subjected to external and internal stimuli. To this regard, perfused vascularized models are a novel field of investigation that can offer a new technological approach to overcome the limitations of traditional cell culture methods. It allows the combination of perfusion, mechanical and biochemical stimuli, biological cues, biomaterials (mimicking the extracellular matrix of bone), and multiple cell types. This review will discuss macro, milli, and microscale perfused devices designed to model bone structure and microenvironment, focusing on the role of perfusion and encompassing different degrees of complexity. These devices are a very first, though promising, step for the development of 3D in vitro platforms for preclinical screening of novel anabolic or anti-catabolic therapeutic approaches to improve bone health.

The Filtragometer: A New Device for Measuring Platelet Aggregation in Venous Blood of Man

1975 ◽  
Vol 34 (02) ◽  
pp. 531-544 ◽  
Author(s):  
G Hornstra ◽  
F ten Hoor
Keyword(s):  
Platelet Aggregation ◽  
Pressure Difference ◽  
Venous Blood ◽  
New Device ◽  
Platelet Aggregates ◽  
Spontaneous Platelet Aggregation ◽  
Short Time ◽  
Forearm Vein

SummaryA new device for the direct assessment of spontaneous platelet aggregation in human venous blood is described: the Filtragometer. The principle of the method is based on measurement of the pressure difference across a filter with pores of 20 μπι diameter through which blood from a forearm vein is drawn. Platelet aggregates, obstructing the filter, cause a change in the pressure difference which is proportional to the degree of platelet aggregation. The measurement takes only a short time and a small amount (5-10 ml) of blood.Platelet aggregation as measured with the Filtragometer depends on the type of anticoagulant used. The Filtragometer response decreases on inhibition of platelet stickiness in vitro by prostaglandin E1 and in vivo by aspirin ingestion. Moreover it appeared to be higher in a group with a high thrombosis tendency than in a group less susceptible to fatal arterial thrombosis.The Filtragometer seems especially useful in monitoring the results of diet and/or drug therapy.

Influence of Fibrinogen Split Products on Platelets

1967 ◽  
Vol 17 (01/02) ◽  
pp. 078-098 ◽  
Author(s):  
M. I Barnhart ◽  
D. C Cress ◽  
R. L Henry ◽  
J. M Riddle
Keyword(s):  
Platelet Aggregation ◽  
Plasma Concentration ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Platelet Response ◽  
Transient Nature ◽  
Platelet Morphology ◽  
Platelet Aggregates

SummaryBreakdown products of fibrinogen and fibrin can play a role in hemostasis and also may be of consequence in thrombosis. β2 fibrinogen derivative D is an electropositive terminal proteolysis product of fibrinolysis which has the ability to aggregate platelets. The normal plasma concentration of such nonclottable fibrinogen relatives is 0.2 mg/ml. During fibrinolysis this concentration may reach 5 mg/ml plasma. Addition of β 2 fibrinogen D (raising the plasma concentration 0.1 to 5 mg/ml) either in vivo or in vitro induced platelet aggregations. Moreover, alterations in platelet morphology occurred which were obvious by electron microscopy.Platelet depletion was a consistent response to the infusion of purified β2 fibrinogen D (8 to 55 mg/kg body weight) into dogs. Circulating platelets decreased as much as 85% but were only temporarily aggregated and reappeared in the circulation within 1 to 5 hrs. Small platelet aggregates circulated while large aggregates were trapped in the microcirculation. Thrombin was not responsible for the platelet aggregations as neither prothrombin nor clottable fibrinogen were changed significantly. The transient nature and morphological features of the platelet response according to microscopic criteria were prominent during and after infusion of β2 fibrinogen D.In vitro studies included 3 systems; washed platelets, platelet rich plasma and whole blood. Positive results were obtained with all, but platelets in whole blood were most responsive. The magnitude of platelet aggregation and morphology correlated with the concentration of β2 fibrinogen D. Platelet aggregation induced by ADP (10~5 mg/ml) was compared with that induced by β2 fibrinogen D (0.09 to 0.72 mg/ml). With either reagent aggregates were of dendritic forms. Combination of the 2 reagents was additive but did not further change the morphology. Additional factors seem necessary for development of viscous metamorphosis.

Platelets, Tumor Cell Invasiveness, and Metastasis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. SCI-31-SCI-31
Author(s):  
Richard O. Hynes ◽  
Shahinoor Begum ◽  
Myriam Labelle
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Conflicts Of Interest ◽  
Cell Types ◽  
Therapeutic Interventions ◽  
Migration And Invasion ◽  
Cell Contact ◽  
Cell Arrest

Abstract Platelets have long been known to promote metastasis, and multiple mechanisms have been proposed to explain this phenomenon, including adhesion, coagulation, and protection against natural killer (NK) cells or turbulence. One mechanism that has been little explored is the possibility that platelets might secrete growth factors or provide other stimuli that could enhance the malignant properties of tumor cells. We have shown that pretreatment of carcinoma cells with platelets induces an EMT-like transformation in their properties in vitro and renders them much more metastatic after introduction into mice. TGF-β, produced by platelets and released on their activation is essential for both the in vitro and the in vivo effects. However, TGF-β alone is insufficient; platelet-tumor cell contact is also required and this contact activates NFkB signaling, which synergizes with the TGF-β signaling. Both signals are required for the enhancement of metastasis. In addition to enhancing migration and invasion in vitro, platelets enhance extravasation in vivo. Earlier work has shown that both P-selectin (expressed on platelets) and L-selectin (expressed on leukocytes) are essential for efficient metastasis, and aggregates of tumor cells, platelets, and leukocytes can be observed at sites of tumor cell arrest and extravasation. It has also been demonstrated by others that leukocytes can enhance extravasation and metastatic seeding. Therefore, we have been interested in the question of the relative roles of platelets and leukocytes in these processes. Which cell types are recruited at the sites of metastatic seeding? Does one cell type depend on another? Which cell types enhance metastasis? What roles do the platelets play in recruiting the other cell types? The involvement of platelets in enhancing metastasis also raises questions about the effects of platelets on circulating tumor cells (CTCs). Could platelets enhance the metastatic capacity of CTCs? Could it be the case that only those CTCs that are associated with platelets and/or leukocytes are functionally involved in seeding metastases? Such aggregates are not scored in most current assays for CTCs and will require new investigative approaches. Platelet participation in metastasis also raises the possibility of therapeutic interventions targeting platelet-specific targets and the paracrine interactions between them and other cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals P11.40 Development of an implantable multifunctional biodevice (GlioGel) in the treatment of recurrent glioblastoma

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii52-iii52
Author(s):  
L Déry ◽  
G Charest ◽  
M Akbari ◽  
D Fortin
Keyword(s):  
Tumor Cells ◽  
Median Survival ◽  
Complete Removal ◽  
Recurrent Glioblastoma ◽  
Control Group ◽  
Rat Glioma ◽  
F98 Rat Glioma ◽  
Glioma Model

Abstract BACKGROUND Glioblastoma (GBM) is a devastating disease with a median survival of 14–16 months. This poor prognosis can be explained by 3 factors. First, the infiltrative nature of the disease prohibits a complete removal of the tumor. Second, some of the tumor cells are brain tumor stem cells, which are highly migratory and highly resistant to treatments. Finally, the presence of the blood-brain barrier prohibits entry of therapeutics. This situation implies that new treatment approaches must be directed toward the infiltrated brain surrounding the resection cavity. To bypass this problem and improve the potency of adjuvant treatment, we have designed a new “GlioGel-device” that will have the ability to: 1- attract the migrating tumor cells into or nearby the device, and 2- subsequently deliver chemotherapy to the locally pooled tumor cells and 3- irradiate these cells with radioisotopes embedded in the GlioGel. MATERIAL AND METHODS In vitro proof of principle of chemoattraction was investigated by agarose drops method releasing chemokines molecules (CCL2, CCL11, CXCL10) with F98 and U87MG GBM cells. In vivo experiments evaluated the efficiency of chemokines and doxorubicin released by the implanted GlioGel on the tumor behaviour in our Fischer-F98 rat glioma model. An histology of tumour behaviour exposed to chemokines and survival of GBM rats treated with doxorubicin were analysed. RESULTS In vitro preliminary results for chemoattraction assays show that up to 2 times more cells invade the gel when it releases chemoattractant compared to PBS. The In vivo chemotherapy experiments with a fast, medium and slow release of doxorubicin from the GlioGel show that a local dose that represent a 1300-fold smaller dose than a normal intravenous systemic dose gave a significant reduction in tumour growth (median survival) compared to a control group. We investigated the effect provided by the GlioGel impregnated with chemokines on tumor cells migration, after implantation in the Fischer-F98 rat glioma model. CONCLUSION This preliminary study shows the ability of GlioGel releasing chemokines and doxorubicin to respectively attract and kill orthotopic glioblastoma cells. These encouraging results will be completed with a combination of short-range (high LET) radiation by embedded radioisotope into the GlioGel aiming for synergistic combination to eradicate as much tumour cells as possible, while limiting systemic side effects.

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