scholarly journals High uptake of 68Ga-PSMA and 18F-DCFPyL in the peritumoral area of rat gliomas due to activated astrocytes

2020 ◽  
Author(s):  
Dennis Oliveira ◽  
Carina Stegmayr ◽  
Alexander Heinzel ◽  
Johannes Ermert ◽  
Bernd Neumaier ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Tumor Model ◽  
Blue Dye ◽  
High Uptake ◽  
Dioic Acid ◽  
Cellular Targets ◽  
Rat Glioma ◽  
Tumor Bearing ◽  
Cerebral Gliomas ◽  
Ex Vivo Autoradiography

Abstract Background Recent studies reported on high uptake of the PSMA ligands [ 68 Ga]HBED-CC ( 68 Ga-PSMA) and 18 F-DCFPyL in cerebral gliomas. This study explores the regional uptake and cellular targets of 68 Ga-PSMA and 18 F-DCFPyL in three different rat glioma models. Methods F98, 9L or U87 rat gliomas were implanted into the brains of 38 rats. After 13 days of tumor growth, 68 Ga-PSMA (n=21) or 18 F-DCFPyL (n=17) were injected intravenously and animals were sacrificed 40 min later. Five animals for each tracer and tumor model were additionally investigated by micro-PET at 20-40 min postinjection. Cryosections of the tumor bearing brains were analyzed by ex vivo autoradiography and immunofluorescence staining for blood vessels, microglia, astrocytes and presence of PSMA. Blood-brain barrier (BBB) permeability was tested by coinjection of Evans blue dye (EBD). 68 Ga-PSMA uptake after restoration of BBB integrity by treatment with dexamethasone (Dex) was evaluated in four animals with U87 gliomas. Competition experiments using the PSMA-receptor inhibitor 2-(Phosphonomethyl)pentane-1,5-dioic acid (PMPA) were performed for both tracers in two animals each. Results Autoradiography demonstrated a strong 68 Ga-PSMA and 18 F-DCFPyL binding in the peritumoral area and moderate binding in the center of the tumors. PMPA administration led to complete inhibition of 68 Ga-PSMA and 18 F-DCFPyL binding in the peritumoral region. Restoration of BBB by Dex treatment reduced EBD extravasation but 68 Ga-PSMA binding remained unchanged. Expression of activated microglia (CD11b) was low in the intra- and peritumoral area but GFAP staining revealed strong activation of astrocytes in congruency to the tracer binding in the peritumoral area. All tumors were visualized in micro PET, showing a lower tumor/brain contrast with 68 Ga-PSMA than with 18 F-DCFPyL. Conclusions High uptake of 68 Ga-PSMA and 18 F-DCFPyL in the peritumoral area of all glioma models is presumably caused by activated astrocytes. This may represent a limitation for the clinical application of PSMA ligands in gliomas.

scholarly journals High uptake of 68Ga-PSMA-HBED-CC and 18F-DCFPyL in the peritumoral area of rat gliomas due to activated astrocytes

2020 ◽  
Author(s):  
Dennis Oliveira ◽  
Carina Stegmayr ◽  
Alexander Heinzel ◽  
Johannes Ermert ◽  
Bernd Neumaier ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Blue Dye ◽  
High Uptake ◽  
Dioic Acid ◽  
Cellular Targets ◽  
Rat Glioma ◽  
Minor Influence ◽  
Ex Vivo Autoradiography ◽  
Bbb Permeability ◽  
A Minor

Abstract Background Recent studies reported on high uptake of the PSMA ligands [68Ga]HBED-CC (68Ga-PSMA) and 18F-DCFPyL in cerebral gliomas. This study explores the regional uptake and cellular targets of 68Ga-PSMA and 18F-DCFPyL in three different rat glioma models.Methods F98, 9L or U87 rat gliomas were implanted into the brains of 38 rats. After 13 days of tumor growth, 68Ga-PSMA (n=21) or 18F-DCFPyL (n=17) were injected intravenously and animals were sacrificed 40 min later. Cryosections of the tumor bearing brains were analyzed by ex vivo autoradiography and immunofluorescence staining for blood vessels, microglia, astrocytes and presence of PSMA. Blood-brain barrier (BBB) permeability was tested by coinjection of Evans blue dye (EBD). 68Ga-PSMA uptake after restoration of BBB integrity by treatment with dexamethasone (Dex) was evaluated in four animals with U87 gliomas. Competition experiments using the PSMA-receptor inhibitor 2-(Phosphonomethyl)pentane-1,5-dioic acid (PMPA) were performed for both tracers in two animals each.Results All tumors showed a strong 68Ga-PSMA and 18F-DCFPyL binding in the peritumoral area and moderate binding in the center of the tumors. PMPA administration led to complete inhibition of 68Ga-PSMA and 18F-DCFPyL binding in the peritumoral region. Restoration of BBB by Dex treatment reduced EBD extravasation but 68Ga-PSMA binding remained unchanged. Expression of activated microglia (CD11b) was low in the intra- and peritumoral area but GFAP staining revealed strong activation of astrocytes in congruency to the tracer binding in the peritumoral area. Conclusions High uptake of 68Ga-PSMA and 18F-DCFPyL in the peritumoral area of all glioma models is presumably caused by activated astrocytes. This may represent a limitation for the clinical application of PSMA ligands in gliomas. BBB permeability had a minor influence on tracer binding.

RG2 glioma growth in rat cerebellum after subdural implantation

1986 ◽  
Vol 65 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Stanislaw Krajewski ◽  
Jürgen C. W. Kiwit ◽  
Wolfgang Wechsler
Keyword(s):  
Light And Electron Microscopy ◽  
Tumor Model ◽  
Nerve Tissue ◽  
Blue Dye ◽  
Histological Techniques ◽  
Content Type ◽  
Rat Glioma ◽  
Glioma Growth ◽  
Microsurgical Techniques ◽  
Fine Print

✓ The nitrosourea-induced rat glioma clone RG2 was tested for its capacity to form multicellular tumor spheroids (MTS's). Resulting spheroids were investigated by light and electron microscopy with regard to their proliferation patterns and morphological features. Using microsurgical techniques and avoiding mechanical injury of the brain tissue, the authors successfully transplanted avascular MTS's under the dura of the cerebellum, above the vermis, in 43 adult syngeneic Fischer CD rats. The rate of tumor establishment was 93%, and the tumors that were solid and spheroid in shape grew exponentially. Neovascularization could be observed at 3 days after implantation, and invasion of the cerebellum occurred by 3 to 5 days. Neurological deterioration, including ataxia, impairment of walking, and apathy, could be observed after 10 days. The mean survival time was approximately 16 days. The subdural cerebellar tumors were studied by histological techniques, and two morphometric methods were applied to check the growth of implanted spheroids. All tumors were deeply stained with the Evans blue dye-albumin complex, demonstrating disturbance of the blood-brain barrier. The easy accessibility of the cerebellar vermis in rats, the microsurgical implantation of glioma spheroids under the dura avoiding nerve tissue disruption, and the high percentage of reproducible establishment of tumors favor this experimental brain-tumor model. This should be an excellent model for study of experimental therapies.

scholarly journals Preclinical PET imaging of bispecific antibody ERY974 targeting CD3 and glypican 3 reveals that tumor uptake correlates to T cell infiltrate

2020 ◽  
Vol 8 (1) ◽  
pp. e000548 ◽  
Author(s):  
Stijn JH Waaijer ◽  
Danique Giesen ◽  
Takahiro Ishiguro ◽  
Yuji Sano ◽  
Naofumi Sugaya ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Cells ◽  
Tumor Targeting ◽  
Bispecific Antibody ◽  
Ex Vivo ◽  
Tumor Uptake ◽  
Immunodeficient Mice ◽  
Tumor Bearing ◽  
Ex Vivo Autoradiography ◽  
Human Immune

BackgroundBispecific antibodies redirecting T cells to the tumor obtain increasing interest as potential cancer immunotherapy. ERY974, a full-length bispecific antibody targeting CD3ε on T cells and glypican 3 (GPC3) on tumors, has been in clinical development However, information on the influence of T cells on biodistribution of bispecific antibodies, like ERY974, is scarce. Here, we report the biodistribution and tumor targeting of zirconium-89 (89Zr) labeled ERY974 in mouse models using immuno-positron emission tomography (PET) imaging.MethodsTo study both the role of GPC3 and CD3 on the biodistribution of [89Zr]Zr-N-suc-Df-ERY974,89Zr-labeled control antibodies targeting CD3 and non-mammalian protein keyhole limpet hemocyanin (KLH) or KLH only were used. GPC3 dependent tumor targeting of [89Zr]Zr-N-suc-Df-ERY974 was tested in xenograft models with different levels of GPC3 expression. In addition, CD3 influence on biodistribution of [89Zr]Zr-N-suc-Df-ERY974 was evaluated by comparing biodistribution between tumor-bearing immunodeficient mice and mice reconstituted with human immune cells using microPET imaging and ex vivo biodistribution. Ex vivo autoradiography was used to study deep tissue distribution.ResultsIn tumor-bearing immunodeficient mice, [89Zr]Zr-N-suc-Df-ERY974 tumor uptake was GPC3 dependent and specific over [89Zr]Zr-N-suc-Df-KLH/CD3 and [89Zr]Zr-N-suc-Df-KLH/KLH. In mice engrafted with human immune cells, [89Zr]Zr-N-suc-Df-ERY974 specific tumor uptake was higher than in immunodeficient mice. Ex vivo autoradiography demonstrated a preferential distribution of [89Zr]Zr-N-suc-Df-ERY974 to T cell rich tumor tissue. Next to tumor, highest specific [89Zr]Zr-N-suc-Df-ERY974 uptake was observed in spleen and lymph nodes.Conclusion[89Zr]Zr-N-suc-Df-ERY974 can potentially be used to study ERY974 biodistribution in patients to support drug development.

PAF increases vascular permeability without increasing pulmonary arterial pressure in the rat

2001 ◽  
Vol 90 (1) ◽  
pp. 261-268 ◽  
Author(s):  
Leonardo C. Clavijo ◽  
Mary B. Carter ◽  
Paul J. Matheson ◽  
Mark A. Wilson ◽  
William B. Wead ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Edema ◽  
Pulmonary Arterial Pressure ◽  
Ex Vivo ◽  
Platelet Activating Factor ◽  
Microvascular Permeability ◽  
Blue Dye ◽  
E Coli ◽  
Pulmonary Arterial

In vivo pulmonary arterial catheterization was used to determine the mechanism by which platelet-activating factor (PAF) produces pulmonary edema in rats. PAF induces pulmonary edema by increasing pulmonary microvascular permeability (PMP) without changing the pulmonary pressure gradient. Rats were cannulated for measurement of pulmonary arterial pressure (Ppa) and mean arterial pressure. PMP was determined by using either in vivo fluorescent videomicroscopy or the ex vivo Evans blue dye technique. WEB 2086 was administered intravenously (IV) to antagonize specific PAF effects. Three experiments were performed: 1) IV PAF, 2) topical PAF, and 3) Escherichia coli bacteremia. IV PAF induced systemic hypotension with a decrease in Ppa. PMP increased after IV PAF in a dose-related manner. Topical PAF increased PMP but decreased Ppa only at high doses. Both PMP (88 ± 5%) and Ppa (50 ± 3%) increased during E. coli bacteremia. PAF-receptor blockade prevents changes in Ppa and PMP after both topical PAF and E. coli bacteremia. PAF, which has been shown to mediate pulmonary edema in prior studies, appears to act in the lung by primarily increasing microvascular permeability. The presence of PAF might be prerequisite for pulmonary vascular constriction during gram-negative bacteremia.

IMMU-29. B-CELL-BASED VACCINE PRODUCES GLIOBLASTOMA-REACTIVE ANTIBODIES THAT CONTRIBUTE TO TUMOR CLEARANCE

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi98-vi98
Author(s):  
Brandyn Castro ◽  
Mark Dapash ◽  
David Hou ◽  
Aida Rashidi ◽  
Deepak Kanojia ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Ex Vivo ◽  
Murine Models ◽  
Effector Functions ◽  
Tumor Bearing ◽  
Tumor Clearance ◽  
Cellular And Humoral Immunity

Abstract Glioblastomas (GBM) are characterized by a strong immunosuppressive environment, contributing to their poor prognosis and limited therapeutic response to immunotherapies. B-cells represent a unique opportunity to promote immunotherapy due to their potential to kill tumors by both cellular and humoral immunity. To generate our B-cell-based vaccine (BVax) platform, we activated 41BBL+ B cells from tumor bearing mice or GBM patient blood with BAFF, CD40, and IFNg. We have previously demonstrated that BVax potentiates radiation therapy, temozolomide and checkpoint blockade in murine models of GBM via enhancement of CD8+ T-cell based immunity. The aim of this current study is to evaluate the humoral effector functions of BVax. We examined the antibody (Ab) repertoire in vivo from serum of tumor-bearing B-cell knockout mice treated with BVax or by ex vivo stimulation of patient-derived BVax. Upon systemic administration, BVax infiltrates the tumor where it differentiates into plasmablasts. Murine BVax- and BNaive-derived serum immunoglobulin generated in vivo showed that the majority of murine BVax-derived Ab were IgG isotype, while BNaive mainly produced IgM isotype. Transfer of IgG from BVax treated mice directly into tumors of recipient animals significantly prolonged their survival, demonstrating anti-tumor cytotoxicity directly through humoral immunity. Patient-derived BVax activated ex vivo showed a plasmablast phenotype and the Ab repertoire supports the previous findings seen in our murine model. Our work suggests BVax-derived IgGs role in antibody-dependent cellular cytotoxicity and improved survival in murine models. This function, in addition to its role in cellular immunity against GBM, renders BVax a potentially effective alternative immunotherapeutic option for GBM patients.

Characterization of an intraperitoneal ovarian cancer xenograft model in nude rats using noninvasive microPET imaging

2007 ◽  
Vol 17 (2) ◽  
pp. 407-417 ◽  
Author(s):  
C. L. Zavaleta ◽  
W. T. Phillips ◽  
Y. C. Bradley ◽  
L. M. McMANUS ◽  
P. A. Jerabek ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Lymph Nodes ◽  
Peritoneal Cavity ◽  
Imaging Modality ◽  
Xenograft Model ◽  
Tumor Model ◽  
Fdg Uptake ◽  
Tumor Bearing ◽  
Nude Rats ◽  
Biodistribution Data

MicroPET is a noninvasive imaging modality that can potentially track tumor development in nude rats using the radiotracer fluorine 18-fluorodeoxyglucose (18F-FDG). Our goal was to determine whether microPET, as opposed to more invasive techniques, could be used to noninvasively monitor the development of ovarian cancer in the peritoneal cavity of nude rats for monitoring treatment response in future studies. Female nude rats were inoculated intraperitoneally with 36 million NIH:OVCAR-3 cells. Imaging was carried out at 2, 4, 6, or 8 weeks postinoculation. Each rat was fasted overnight and intravenously injected with 11.1 MBq (300 μCi) of 18F-FDG in 0.2 mL of saline. Thirty minutes following injection, the rats were placed in the microPET and scanned for 30 min. After imaging, rats were euthanized for ascites and tissue collection for biodistribution and histopathologic correlation. Standard uptake values (SUVs) of 18F-FDG within the peritoneal cavity were also calculated from regions of interest analysis of the microPET images. MicroPET images showed diffuse increased uptake of 18F-FDG throughout the peritoneal cavity of tumor rats (mean SUV = 4.64) compared with control rats (mean SUV = 1.03). Ascites gathered from tumor-bearing rats had increased 18F-FDG uptake as opposed to the peritoneal fluid collected from control rats. Biodistribution data revealed that the percent injected dose per gram (% ID/g) was significantly higher in tumor-bearing rats (6.29%) than in control rats (0.59%) in the peritoneal lymph nodes. Pathology verified that these lymph nodes were more reactive in tumor-bearing rats. By 6 weeks, some rats developed solid masses within the peritoneum, which could be detected on microPET images and confirmed as tumor by histopathology. 18F-FDG uptake in these tumors at necropsy was 2.83% ID/g. These results correlate with previous invasive laparoscopic studies of the same tumor model and demonstrate that microPET using 18F-FDG is a promising noninvasive tool to localize and follow tumor growth in an intraperitoneal ovarian cancer model.

scholarly journals Impact of Energy and Access Methods on Extrahepatic Tumor Spreading and the Ablation Zone: An Ex vivo Experiment Using a Subcapsular Tumor Model

2019 ◽  
Vol 20 (4) ◽  
pp. 580
Author(s):  
Jin Sil Kim ◽  
Youngsun Ko ◽  
Hyeyoung Kwon ◽  
Minjeong Kim ◽  
Jeong Kyong Lee
Keyword(s):  
Ex Vivo ◽  
Tumor Model ◽  
Ablation Zone ◽  
Access Methods

α7β1-Integrin regulates mechanotransduction and prevents skeletal muscle injury

2006 ◽  
Vol 290 (6) ◽  
pp. C1660-C1665 ◽  
Author(s):  
Marni D. Boppart ◽  
Dean J. Burkin ◽  
Stephen J. Kaufman
Keyword(s):  
Skeletal Muscle ◽  
Muscle Damage ◽  
Intracellular Signaling ◽  
Ex Vivo ◽  
Negative Regulator ◽  
Blue Dye ◽  
The Matrix ◽  
Mitogen Activated Protein ◽  
Exercise Induced

α7β1-Integrin links laminin in the extracellular matrix with the cell cytoskeleton and therein mediates transduction of mechanical forces into chemical signals. Muscle contraction and stretching ex vivo result in activation of intracellular signaling molecules that are integral to postexercise injury responses. Because α7β1-integrin stabilizes muscle and provides communication between the matrix and cytoskeleton, the role of this integrin in exercise-induced cell signaling and skeletal muscle damage was assessed in wild-type and transgenic mice overexpressing the α7BX2 chain. We report here that increasing α7β1-integrin inhibits phosphorylation of molecules associated with muscle damage, including the mitogen-activated protein kinases (JNK, p38, and ERK), following downhill running. Likewise, activation of molecules associated with hypertrophy (AKT, mTOR, and p70S6k) was diminished in mice overexpressing integrin. While exercise resulted in Evans blue dye-positive fibers, an index of muscle damage, increased integrin protected mice from injury. Moreover, exercise leads to an increase in α7β1 protein. These experiments provide the first evidence that α7β1-integrin is a negative regulator of mechanotransduction in vivo and provides resistance to exercise-induced muscle damage.

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