Reduction In Vascular Permeability Research Articles

Depth of Radiographic Response and Time to Tumor Regrowth Predicts Overall Survival Following Anti-VEGF Therapy in Recurrent Glioblastoma.

Antiangiogenic therapies are known to cause high radiographic response rates due to reduction in vascular permeability resulting in a lower degree of contrast extravasation. In this study, we investigate the prognostic ability for model-derived parameters describing enhancing tumor volumetric dynamics to predict survival in recurrent glioblastoma treated with antiangiogenic therapy. N = 276 patients in two phase II trials were used as training data, including bevacizumab ± irinotecan (NCT00345163) and cabozantinib (NCT00704288), and N = 74 patients in the bevacizumab arm of a phase III trial (NCT02511405) were used for validation. Enhancing volumes were estimated using T1 subtraction maps, and a biexponential model was used to estimate regrowth (g) and regression (d) rates, time to tumor regrowth (TTG), and the depth of response (DpR). Response characteristics were compared to diffusion MR phenotypes previously shown to predict survival. Optimized thresholds occurred at g = 0.07 months-1 (phase II: HR = 0.2579, P = 5 × 10-20; phase III: HR = 0.2197, P = 5 × 10-5); d = 0.11 months-1 (HR = 0.3365, P < 0.0001; HR = 0.3675, P = 0.0113); TTG = 3.8 months (HR = 0.2702, P = 6 × 10-17; HR = 0.2061, P = 2 × 10-5); and DpR = 11.3% (HR = 0.6326, P = 0.0028; HR = 0.4785, P = 0.0206). Multivariable Cox regression controlling for age and baseline tumor volume confirmed these factors as significant predictors of survival. Patients with a favorable pretreatment diffusion MRI phenotype had a significantly longer TTG and slower regrowth. Recurrent glioblastoma patients with a large, durable radiographic response to antiangiogenic agents have significantly longer survival. This information is useful for interpreting activity of antiangiogenic agents in recurrent glioblastoma.

Depth of radiographic response (DpR) and time to tumor regrowth (TTG) to predict overall survival following anti-VEGF therapy in recurrent glioblastoma.

2063 Background: Anti-angiogenic therapies, anti-VEGF agents, cause high radiographic response rates due to reduction in vascular permeability. However, we theorized the degree of tumor shrinkage combined with the duration of response might be a more meaningful measure of tumor control and may better reflect real patient benefit. In the current study, we investigate the association between model-derived parameters describing enhancing tumor volumetric dynamics and overall survival (OS) in recurrent glioblastoma treated with anti-VEGF therapy from multiple clinical trials. Methods: N=134 patients treated with bevacizumab +/- irinotecan (BRAIN Trial; NCT00345163) and N=121 patients treated with cabozantinib (XL184-201; NCT00704288) were used to identify potential imaging biomarkers, and N=63 patients in the bevacizumab control arm in a phase III trial (GLOBE Trial; NCT02511405) were used as a validation dataset. Enhancing tumor volumes were estimated using T1 subtraction maps, and a biexponential model was used to model tumor response ( d) and regrowth ( g) rates, as well as time to tumor regrowth ( TTG), the inflection point where the tumor stops shrinking and starts to regrow, and the depth of response ( DpR) after initiation of anti-VEGF therapy for each patient. Log-rank, univariate, and multivariable Cox regression were used to quantify the relationship of these parameters and OS. Results: Optimized thresholds based on maximum hazard ratio occurred at d =0.11 months-1 ( P=5x10-9 training; P=0.0082 validation); g=0.07 months-1 ( P=5x10-20 training; P&lt;0.0001 validation); TTG of 3.8 months ( P=6x10-17training; P&lt;0.0001 validation); and DpR of 11.3% ( P=0.0026 training; P=0.0177 validation). Univariate and multivariable Cox regression using these thresholds and controlling for age and baseline tumor volume confirmed that d, g, TTG, and DpR were all significant and independent predictors of OS in both phase II training and phase III validation datasets ( P&lt;0.01). Additionally, patients exhibiting combinations of a high DpR and/or long TTG showed differential median OS, while patients with favorable diffusion MR phenotypes exhibited a longer OS and significantly longer TTG. Conclusions: Volumetric response and regrowth rates, TTG, and DpR using a biexponential model are significant and independent predictors of OS in recurrent glioblastoma treated with anti-VEGF therapy. Clinical trial information: NCT00345163 ; NCT00704288 ; NCT02511405 .

ANGI-03. TARGETING ANGIOGENIC PATHWAYS IN COMBINATION WITH OHSV THERAPY IN GBM

Abstract Glioblastoma (GBM) is the most aggressive brain malignancy, which despite continuing worldwide efforts to develop new therapies, remains a deadly disease with limited treatment options. The asparagine hydroxylase factor inhibiting HIF (FIH1) is located in chromosome 10q24, a region often deleted in GBM, suggesting a tumor protective role. FIH1 has been implicated in GBM as an inhibitor of HIF1α-mediated transcription of VEGF-A, leading to decreased angiogenesis. We previously showed that oncolytic HSV (oHSV) infection reduces the expression FIH1 via a virus encoded miRNA. Furthermore, we have found that FIH1 also negatively regulates NOTCH signaling, which is elevated following oHSV treatment. Thus, we hypothesize that FIH1 reconstitution in tumors will block pro-tumorigenic NOTCH and HIF1α signaling. Using FIH1-overexpressing GBM cells we observed a reduction in vascular permeability, measured by intravital imaging, and decreased expression of angiogenesis markers. In vivo, combination of FIH1 overexpression with oHSV treatment resulted in enhanced survival in mice bearing intracranial GBM tumors. Furthermore, FIH1 overexpression correlated with the enrichment of genes associated with oxidative phosphorylation and ROS pathways, suggesting the potential for multi-modality therapeutic strategies.

Calcineurin Aα Contributes to IgE-Dependent Mast-Cell Mediator Secretion in Allergic Inflammation

Mast cells (MCs) are key mediators of allergic inflammation through the activation of cross-linked immunoglobulin E (IgE) bound to the high-affinity IgE receptor (FcϵRI) on the cell surface, leading to the release of biologically potent mediators, either from preformed granules or newly synthesized. Pharmacological inhibitors have been developed to target a key signaling protein phosphatase in this pathway, calcineurin, yet there is a lack of genetic and definitive evidence for the various isoforms of calcineurin subunits in FcϵRI-mediated responses. In this study, we hypothesized that deficiency in the calcineurin Aα isoform will result in a decreased allergic immune response by the MCs. In a model of passive cutaneous anaphylaxis, there was a reduction in vascular permeability in MC-deficient mouse tissues reconstituted with calcineurin subunit A (CnAα) gene-knockout (CnAα^−/−) MCs, and in vitro experiments identified a significant reduction in release of preformed mediators from granules. Furthermore, released levels of de novo synthesized cytokines were reduced upon FcϵRI activation of CnAα^−/− MCs in vitro. Characterizing the mechanisms associated with this deficit response, we found a significant impairment of nuclear factor of kappa light polypeptide gene enhancer in B cell phosphorylation and impaired nuclear factor kappa-light-chain-enhancer of activated B-cell inhibitor alpha (NF-κB) activation. Thus, we concluded that CnAα contributes to the release of preformed mediators and newly synthesized mediators from FcϵRI-mediated activation of MCs, and this regulation includes NF-κB signaling.

Inhalable Porous Microspheres Loaded with Metformin and Docosahexaenoic Acid Suppress Tumor Metastasis by Modulating Premetastatic Niche.

Cancer metastasis is the major cause of cancer-related death; therefore, achieving suppression of tumor metastasis is a long-sought goal in cancer therapy. As the premetastatic niche acts as a prerequisite for tumor metastasis, it serves as an effective target for metastasis suppression. This study tests the feasibility of inhalable porous microspheres loaded with two premetastatic niche modulation agents, metformin and docosahexaenoic acid, as orthotopic delivery carriers for the reversion of lung premetastatic microenvironments and targeted suppression of tumor lung metastasis. The microspheres were prepared via an improved emulsion-solvent evaporation method and exhibit an excellent lung deposition, leading to significant inhibition of circulating tumor cells (CTCs)-endothelial cells adhesion, reduction of vascular permeability, and suppression of adhesion protein expression in lung premetastatic microenvironments. As a result, inhalable microspheres can prevent tumor lung metastasis formation excellently in vivo. Overall, this study proved that the encapsulation of metformin and docosahexaenoic acid in inhalable microspheres could be a promising strategy for tumor lung metastasis inhibition via orthotopically modulating premetastatic niche in the lungs.

Modular cell-assembled adipose matrix-derived bead foams as a mesenchymal stromal cell delivery platform for soft tissue regeneration

With the goal of establishing a new clinically-relevant bioscaffold format to enable the delivery of high densities of human adipose-derived stromal cells (ASCs) for applications in soft tissue regeneration, a novel “cell-assembly” method was developed to generate robust 3-D scaffolds comprised of fused networks of decellularized adipose tissue (DAT)-derived beads. In vitro studies confirmed that the assembly process was mediated by remodelling of the extracellular matrix by the seeded ASCs, which were well distributed throughout the scaffolds and remained highly viable after 8 days in culture. The ASC density, sulphated glycosaminoglycan content and scaffold stability were enhanced under culture conditions that included growth factor preconditioning. In vivo testing was performed to compare ASCs delivered within the cell-assembled DAT bead foams to an equivalent number of ASCs delivered on a previously-established pre-assembled DAT bead foam platform in a subcutaneous implant model in athymic nude mice. Scaffolds were fabricated with human ASCs engineered to stably co-express firefly luciferase and tdTomato to enable long-term cell tracking. Longitudinal bioluminescence imaging showed a significantly stronger signal associated with viable human ASCs at timepoints up to 7 days in the cell-assembled scaffolds, although both implant groups were found to retain similar densities of human ASCs at 28 days. Notably, the infiltration of CD31+ murine endothelial cells was enhanced in the cell-assembled implants at 28 days. Moreover, microcomputed tomography angiography revealed that there was a marked reduction in vascular permeability in the cell-assembled group, indicating that the developing vascular network was more stable in the new scaffold format. Overall, the novel cell-assembled DAT bead foams represent a promising platform to harness the pro-regenerative paracrine functionality of human ASCs and warrant further investigation as a clinically-translational approach for volume augmentation.

Arsenic: A Cause of Cardiometabolic Syndromes

Objective: The objective of the study is to identify major pathological biomarkers and their possible mechanisms in arsenic-induced cardiometabolic syndrome. Methodology: The present review summarizes the data and literature taken from previously done studies from Research Gate, Science Direct, PubMed, PubMed Central, Medline, and some other scientific databases emphasizing the role of arsenic in cardiometabolic syndrome. The results obtained through this database were assembled, composed, critically elucidated and presented in explanatory and tabular form. Results: The major pathological target of arsenic is antioxidant defense system and increase in Reactive Oxygen Species reduces the Nitric oxide production, reduction in vascular permeability, increases adhesion and production of inflammatory mediators (IL-6, TNF-á,), TCs, TGs, LDL-C, lipid peroxidation, â-cells dysfunction. The persistent accumulation and generation of these pathological biomarkers in blood vessels can induce hyperlipidemias, dyslipidemias, atherosclerosis, hypertension and diabetes. Conclusion: There is a need to propose natural antioxidant with minimum side effects in the treatment of CMTs.

Evaluation of Angiopoietin One and Angiopoietin Two with Missed Abortion

Missed abortion (MA) is a type of miscarriage, refer to pregnancy in which there is fetal demise without intervention, and also uterine that may expel the product of conception prior to 20 weeks of gestation to assess the role of ANG1 and ANG2 level in early pregnancy and compare these level with healthy pregnancy women, ANG1 play role in new blood vessels maturation and stabilization, the inhibition of endothelial apoptosis and reduction of vascular permeability in stable environment. ANG2 is an antagonist of ANG1 and it known to enhance the plasticity, destabilization and permeability of blood vessels and vascular remodeling site. A prospective cross - study, all women were attended to obstetrics and gynecology outpatient,and this study was carried out from Jan 2019 to July 2019. Sixty Women with missed miscarriage fetus heart negative 6-8 weeks were screened to participate in the present study group, Ages were between 18 – 35 years old, and they were from center and the periphery of Kirkuk city to comparative forty apparently health women with early pregnancy fetus heart positive a control groups. A serum level of ANG1 and ANG2 was measured by ELIZA. The result shows that the mean serum level of Angiopoietin one was significantly decrease in missed mischarge compared to control women (2.92±2.4 vs. 5.6±3.2 ng/ml) respectively at a P &lt; 0.05. And this study showed that there was the significant decrease serum level of angiopoietin two in missed miscarriage patients compared with the control group women (8.12±3.5 vs. 16.81 ±12.3). This study showed that there were the positive correlations of Angiopoietin one and two with missed miscarriage. It can be conclude that the level of serum Angiopoietin -1 and level of serum angiopoietin -2 in missed abortion decrease and it is can be used as an early and effective biomarker for diagnosis of missed abortion.

Polyphenols Modulate Quiescence/Mobilization of Hematopoietic Immature Cells through APC/EPCR/PAR-1 Axis

Coordinated arrangement of bone marrow (BM) microenvironment is essential for the maintenance of hematopoietic stem cells and their progenitors (HSPC), and for the continuous supply of peripheral blood (PB) cells. Quiescence and/or mobilization of these BM cells into the circulation are tightly regulated however non-physiological or stress conditions, such as infections, can accelerate them. Our previous findings have shown that polyphenols from green tea modulate the myeloid population (Gr-1+Mac-1+) of BM, spleen and PB of mice challenged by lipopolysaccharide (LPS). We have also observed a reduction in the circulating levels of thrombin-antithrombin complex (TAT) and soluble endothelial protein C receptor (sEPCR) of these mice. It has been reported that thrombin induces the rapid HSPC mobilization through coagulation thrombin/PAR-1 axis, and quiescence is maintained across the APC/EPCR/PAR-1 axis (Nat. Med. 2015, 21:1307-17). In this context, our goal was to investigate the effects of polyphenols on the Lin-Sca-1+c-Kit+ (LSK) primitive stem cell population and mature populations including: T and B lymphocytes, monocytes, granulocytes and erythrocytes (Lin+). The expression of PAR-1 and EPCR in these cells, and the levels of sEPCR in the BM fluid were also evaluated. The 250 mg/kg dose of polyphenol from green tea extract was given once every 7 days orally (gavage) to mice (n=6/group) challenged with i.p. injection of 100µg LPS. Control group received vehicle only. After 24h, mice were sacrificed; BM and PB were collected for the assays. LPS injection induced an increase in circulating LSK, without affecting the pool of these cells in BM. Treatment with polyphenols prevented recruitment of LSK into the PB, and did not alter the percentage of BM LSK. Corroborating these findings, polyphenols also reduced the number of immature progenitors (CFU-C) in the PB, evaluated by the clonal culture assay. In addition, polyphenols did not affect the increase in the number of Lin+ cells and circulating leukocytes (total WBC) induced by LPS injection. We also observed that LPS induced a rapid increase in the number of PB LSK and Lin+ cells expressing PAR-1, while reducing BM LSK expressing EPCR. Polyphenols did not affect PAR-1 expression in both populations, but partially recovered expression of EPCR in BM LSK. Polyphenols also reduced the increased levels of sEPCR induced by LPS in the BM niche. Taken together, our results demonstrate that polyphenols promote an effect on the quiescence/mobilization of both the most primitive hematopoietic cells and their progenitors, but does not affect mature populations. The reduction in vascular permeability observed in the BM of mice using Evans blue reinforces this action of polyphenols. It appears that the effect of polyphenols is thrombin dependent; although polyphenols did not affect the expression of PAR-1, they modulated EPCR, mainly in the medullary microenvironment with maintenance of barrier integrity and consequent cellular quiescence. In addition, polyphenols appear to have an anti-inflammatory effect, possibly triggered by their effect on the EPCR. DisclosuresDe Paula:Hematology and Transfusion Medicine Center, University of Campinas: Employment. Shiraishi:Hematology and Transfusion Medicine Center, University of Campinas: Employment. Queiroz:University of Campinas: Employment.

Comparison of dynamic contrast-enhanced magnetic resonance imaging and contrast-enhanced ultrasound for evaluation of the effects of sorafenib in a rat model of hepatocellular carcinoma

ObjectivesTo compare the accuracy of contrast-enhanced ultrasound (CEUS) and Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the assessment of changes in tissue vascularization as result of sorafenib treatment in a rat model of hepatocellular carcinoma (HCC). MethodsMale Buffalo rats with orthotopic liver tumors treated daily with 7.5 mg/kg sorafenib via oral gavage for 2 weeks (n = 9) were subject to DCE-MRI and CEUS 2 weeks after tumor implantation - right before treatment initiation - and also after treatment completion - right before tumor harvest. Untreated animals (n = 10) were used as control. Tumor tissue sections were stained for hematoxylin-eosin, pimonidazole, and CD34 for quantitative assessment of necrosis, hypoxia, and microvessel density (MVD), respectively. ResultsOf all the DCE-MRI parameters that were evaluated, only volume transfer constant (Ktrans) measurements were significantly lower in sorafenib-treated tumors (0.18 vs 0.33 min−1, p < 0.01), indicating a substantial decrease in vascular permeability caused by the therapy. This reduction was associated with decreased MVD (3.9 vs 10.8% CD34+ cells, p < 0.01), higher tumor necrosis (31.9 vs 21.8%, p < 0.001) and hypoxia (19.7 vs 10.5% pimonidazole binding, p < 0.01). Moreover, statistical analysis demonstrate significant correlation of DCE-MRI Ktrans with histopathologic tissue necrosis (r = −0.537, p < 0.05) and MVD (r = 0.599, p < 0.05). Interestingly, none of the CEUS measurements were significantly different between the control and treatment groups, and did not show statistical correlation with any of the histopathological parameters assessed (p > 0.05). ConclusionsSorafenib-induced reduction in vascular permeability in this preclinical model of HCC is detected more accurately through DCE-MRI than CEUS, and DCE-MRI parameters strongly correlate with histopathological changes in tissue vascularization and tissue necrosis.

Saquinavir plus methylprednisolone ameliorates experimental acute lung injury.

Glucocorticoid insensitivity is an important barrier to the treatment of several inflammatory diseases, including acute lung injury (ALI). Saquinavir (SQV) is an inhibitor of the human immunodeficiency virus protease, and the therapeutic effects of SQV in ALI accompanied with glucocorticoid insensitivity have not been previously investigated. In this study, the effects of SQV on lipopolysaccharide (LPS)-mediated injury in human pulmonary microvascular endothelial cells (HPMECs), human type I alveolar epithelial cells (AT I), and alveolar macrophages were determined. In addition, the effects of SQV on an LPS-induced ALI model with or without methylprednisolone (MPS) were studied. In LPS-stimulated HPMECs, SQV treatment resulted in a decrease of high mobility group box 1 (HMGB1), phospho-NF-κB (p-NF-κB), and toll-like receptor 4 (TLR4), and an increase of VE-cadherin. Compared to MPS alone, MPS plus SQV attenuated the decrease of glucocorticoid receptor alpha (GRα) and IκBα in LPS-stimulated HPMECs. HMGB1, TLR4, and p-NF-κB expression were also lessened in LPS-stimulated alveolar macrophages with SQV treatment. In addition, SQV reduced the injury in human AT I with a decrease of HMGB1 and p-NF-κB, and with an increase of aquaporin 5 (AQP 5). SQV ameliorated the lung injury caused by LPS in rats with reductions in vascular permeability, myeloperoxidase activity (MPO) and histopathological scores, and with lowered HMGB1, TLR4, and p-NF-κB expression, but with enhanced VE-cadherin expression. By comparison, SQV plus MPS increased GRα and IκBα in lung tissues of rats with ALI. This study demonstrated that SQV prevented experimental ALI and improved glucocorticoid insensitivity by modulating the HMGB1/TLR4 pathway.

Evaluation of the Response of Intracranial Xenografts to VEGF Signaling Inhibition Using Multiparametric MRI

Vascular endothelial growth factor A (VEGF-A) is considered one of the most important factors in tumor angiogenesis, and consequently, a number of therapeutics have been developed to inhibit VEGF signaling. Therapeutic strategies to target brain malignancies, both primary brain tumors, particularly in pediatric patients, and metastases, are lacking, but targeting angiogenesis may be a promising approach. Multiparametric MRI was used to investigate the response of orthotopic SF188luc pediatric glioblastoma xenografts to small molecule pan-VEGFR inhibitor cediranib and the effects of both cediranib and cross-reactive human/mouse anti-VEGF-A antibody B20-4.1.1 in intracranial MDA-MB-231 LM2–4 breast cancer xenografts over 48 hours. All therapeutic regimens resulted in significant tumor growth delay. In cediranib-treated SF188luc tumors, this was associated with lower Ktrans (compound biomarker of perfusion and vascular permeability) than in vehicle-treated controls. Cediranib also induced significant reductions in both Ktrans and apparent diffusion coefficient (ADC) in MDA-MB-231 LM2–4 tumors associated with decreased histologically assessed perfusion. B20-4.1.1 treatment resulted in decreased Ktrans, but in the absence of a change in perfusion; a non-significant reduction in vascular permeability, assessed by Evans blue extravasation, was observed in treated tumors. The imaging responses of intracranial MDA-MB-231 LM2–4 tumors to VEGF/VEGFR pathway inhibitors with differing mechanisms of action are subtly different. We show that VEGF pathway blockade resulted in tumor growth retardation and inhibition of tumor vasculature in preclinical models of pediatric glioblastoma and breast cancer brain metastases, suggesting that multiparametric MRI can provide a powerful adjunct to accelerate the development of antiangiogenic therapies for use in these patient populations.

Impact of selective anti-BMP9 treatment on tumor cells and tumor angiogenesis

The role of bone morphogenic protein 9 (BMP9) signaling in angiogenesis has been controversial, with a number of studies showing that it acts either as a pro-angiogenic or, conversely, as an anti-angiogenic factor in a context-dependent manner. Notably, BMP9 was also reported to function in both pro- or anti-tumorigenic roles during tumor progression. It has therefore remained unclear, whether selective BMP9 inhibition is a useful target for antibody therapy of cancer. To shed light on these questions, we characterized BMP9 expression in plasma of patients with different cancer indications and found elevated levels of pro-domains and precursor BMP9 with a strong response in renal cell carcinoma (RCC). These studies prompted us to evaluate the potential of selective anti-BMP9 cancer therapy in RCC. We generated a novel monoclonal therapeutic antibody candidate, mAb BMP9-0093, that selectively targets all different BMP9 variants but does not bind to the closest homolog BMP10. In vitro, mAb BMP9-0093 treatment inhibited signaling, endothelin-1 (ET-1) production and spreading of endothelial cells and restored BMP9-induced decrease in pericyte migration and attachment. Furthermore, BMP9-mediated epithelial–mesenchymal transition of renal cell carcinoma cells was reversed by mAb BMP9-0093 treatment in vitro. In vivo, mAb BMP9-0093 showed significant anti-tumor activity that was associated with an increase in apoptosis as well as a decrease in tumor cell proliferation and ET-1 release. Furthermore, mAb BMP9-0093 induced mural cell coverage of endothelial cells, which was corroborated by a reduction in vascular permeability, demonstrated by a diminished penetration of omalizumab-Alexa 647 into tumor tissue. Our findings provide new evidence for a better understanding of BMP9 contribution in tumor progression and angiogenesis that may result in the development of effective targeted therapeutic interventions.

The Comparative Effect of Medicinal Herb Feverfew with that of a Synthetic Parthenolide to Assess the Expression of Inducible Cyclo-oxygenase and Anti-inflammatory Activity

Aims: This paper describes the expression of inducible cyclooxygenase and anti-inflammatory of medicinal herb feverfew with a synthetic parthenolide. Study Design: In vivo model to study the expression of inducible cyclooxygenase and anti-inflammatory activity of leaf extract of T. parthenium and synthetic compound parthenolide. Place and Duration of Study: Central Research Laboratory, K. S. Hegde Medical Academy, Derlakatte, Mangalore, Karnataka, India between August 2015 and November 2015. Methodology: The inhibitory effect of COX-1 and COX -2 were assessed in the serum of mice with the treated groups of aqueous and ethanolic extract of T. parthenium (100 mg/kg) and synthetic compound parthenoilde (4 mg/kg) using Cayman’s COX activity assay kit. The anti-inflammatory activity was evaluated by Ethyl phenylpropiolate induced ear edema and carrageenan induced hind paw edema. Results: The ability of the aqueous and ethanolic extract of T. parthenium (100 mg/kg) and synthetic compound parthenoilde (4 mg/kg) to inhibit cyclooxygenase enzymes (COX-1 and COX-2) was significant when compared to control. T. parthenium leaf extracts and synthetic compound reduced the Ethyl phenylpropiolate induced ear edema and carrageenan induced hind paw edema respectively. Conclusion: The result indicates that the inhibitory effect of aqueous and ethanolic extract of T. parthenium and synthetic compound parthenoilde anti-inflammatory activity by Carrageenan induced paw edema and Ethyl phenylpropiolate induced ear edema reduced the inflammation demonstrated through the reduction of vascular permeability may be due to the inhibition of cyclo-oxygenase leading to inhibition of prostaglandin synthesis. Hence the study suggests that selected plants can be considered as a resource for searching novel anti-inflammatory agents possessing COX-2 inhibition.

Abstract 397: Rebastinib potently inhibits function of perivascular TIE2 expressing macrophages in vitro and in vivo

Abstract Introduction Significant cross-talk between tumor cells and the surrounding stromal tissue are essential for tumor vascularization, survival, immunotolerance, invasion, and metastasis. The angiopoietin (ANG)/TIE2 kinase signaling pathway is a pivotal cross talk axis in the tumor microenvironment. It has been demonstrated that TIE2-expressing macrophages (TEMs) mediate invasion and metastasis in the PyMT syngeneic breast cancer model, and that TIE2 expression correlates with poor overall survival and high risk of metastasis in breast cancer patients. In this study, rebastinib was evaluated as a TIE2 inhibitor in in vitro and in vivo models, and was shown to have profound effects on the structure and function of perivascular TEMs. Procedures TIE2 kinase assays used a standard PK/LDH coupled spectrophotometric continuous assay. CHO cells were transiently transfected to express human TIE2 for cellular studies. CHOs, HUVECs and EA.hy926 cells were used to evaluate rebastinib for inhibition of ANG1-stimulated TIE2 phosphorylation. In vitro intravasation studies were performed in a transwell transendothelial migration chamber wherein TIE2HI macrophages interact with breast tumor cells to cause transendothelial migration of tumor cells across a sealed HUVEC endothelial monolayer. In vivo evaluations of rebastinib were performed using intravital high-resolution two-photon microscopy in the murine PyMT breast cancer model to evaluate effects on tumor vascular permeability and tumor cell intravasation. Results Rebastinib is a potent inhibitor of TIE2 kinase (IC50 = 0.63 nM). Rebastinib slowly dissociated from TIE2 (koff = 0.0012 minutes−1; T1/2 = 10 hr). In HUVECs or EA.hy926 cells, rebastinib inhibited ANG1-stimulated TIE2 kinase activity (IC50s of 0.018 and 0.091 nM, respectively). In TIE2 CHO cells, rebastinib inhibited TIE2 phosphorylation (IC50 2.0 nM), and demonstrated a prolonged off-rate (&amp;gt; 24 hr) against TIE2 after inhibitor washout. Rebastinib exhibited an IC50 &amp;lt; 5 nM for inhibiting macrophage-inducedbreast tumor cell intravasation in the in vitro transwell transendothelial migration assay. Rebastinib was evaluated in vivo in the PyMT syngeneic breast cancer model. Rebastinib dosed at 10 mg/kg orally twice weekly impaired tumoral perivascular TEMs, resulting in a significant reduction in vascular permeability and in tumor cell intravasation as quantified by CTCs. Conclusion Rebastinib is a potent inhibitor of TIE2 kinase and exhibits durable cellular inhibition in endothelial cells and in TIE2 macrophages. Oral dosing of rebastinib resulted in a significant reduction in TIE2-macrophage mediated tumor vascular permeability and in the intravasation of tumor cells into the circulation. Rebastinib is currently in Phase 1 clinical evaluation in solid tumors. Citation Format: Allison Harney, Jeanine Pignatelli, Edison Leung, Maja Oktay, Yarong Wang, Bryan D. Smith, Daniel L. Flynn, John S. Condeelis. Rebastinib potently inhibits function of perivascular TIE2 expressing macrophages in vitro and in vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 397. doi:10.1158/1538-7445.AM2015-397

Abstract 5125: Imaging the tumor microenvironment of metastasis reveals the mechanism of transient blood vessel permeability and tumor cell intravasation

Abstract Sites of direct contact between a macrophage, a tumor cell and endothelial cell [Tumor MicroEnvironment of Metastasis (TMEM)], correlates with metastasis in breast cancer patients independently of other clinical prognostic indicators suggesting a direct role for TMEM function in hematogenous dissemination. Here we show, using intravital high-resolution two-photon microscopy, that tumor cell intravasation occurs only at TMEM. Tumor cell intravasation occurs concurrently with transient, local vascular permeability at TMEM in an autochthonous mouse mammary carcinoma model and a human patient-derived xenograft model. Ablation of the presence or activity of the TMEM associated macrophages blocks tumor cell intravasation at TMEM demonstrating an essential role of perivascular macrophages in TMEM function. A subset of TMEM macrophages are identified as Tie2-expressing macrophages that are characterized by F4/80+/CD11b+/CD68+/MRC1+/Tie2Hi/VEGFAHi/CD11c-. VEGFA signaling from Tie2Hi TMEM-associated macrophages causes the local loss of vascular junctions resulting in transient vascular permeability and tumor cell intravasation at TMEM. Macrophage-specific ablation of VEGFA results in increased vascular junction stability and inhibition of intravasation, demonstrating that vascular junction dissolution at VEGFAHi/Tie2Hi TMEM-associated macrophages leads to vascular permeability and tumor cell intravasation. Inhibition of Tie2 with the first in class small molecular inhibitor rebastinib impairs TMEM function leading to a reduction in vascular permeability, tumor cell dissemination and metastasis. Further, rebastinib inhibition of Tie2 blocks tumor cell extravasation and metastatic growth in the lungs. Together, the findings that TMEM macrophages mediate vascular permeability and tumor cell intravasation demonstrate an essential role for TMEM within the primary mammary tumor as sites of tumor cell dissemination. These data reveal the mechanism of tumor cell intravasation in breast cancer, explain the prognostic value of TMEM density in predicting distant metastatic recurrence in breast cancer patients and document a strategy for inhibition of dissemination. This research is supported by the Department of Defense Breast Cancer Research Program under award number BC120227 (ASH), NIH CA100324 (JSC) and the Integrated Imaging Program. Citation Format: Allison S. Harney, Esther N. Arwert, David Entenberg, Yarong Wang, Peng Guo, Bin-Zhi Qian, Bryan D. Smith, Jeffrey W. Pollard, Joan G. Jones, Daniel L. Flynn, John S. Condeelis. Imaging the tumor microenvironment of metastasis reveals the mechanism of transient blood vessel permeability and tumor cell intravasation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5125. doi:10.1158/1538-7445.AM2015-5125

Brain perfusion and permeability in patients with advanced, refractory glioblastoma treated with lomustine and the transforming growth factor-β receptor I kinase inhibitor LY2157299 monohydrate.

Transforming growth factor-β (TGF-β) signaling is associated with tumor progression and vascularization in malignant glioma. In the present study, magnetic resonance imaging was used to evaluate changes in the size and vascularity of glioblastomas in 12 patients who were treated with lomustine and the novel inhibitor of TGF-β signaling, LY2157299 monohydrate. A response in tumor size was observed in 2 of the 12 patients; in 1 of these 2 patients, a reduction in vascular permeability and perfusion was also detected. The effect was observed following 4 cycles of treatment (~3 months). Changes in vascularity have not previously been attributed to treatment with lomustine; therefore, the effect may be associated with LY2157299 treatment. LY2157299 does not appear to have an anti-angiogenic effect when combined with lomustine, and hence may have a different mechanism of action profile compared with anti-angiogenic drugs.

Dopamine receptor 2 activation inhibits ovarian vascular endothelial growth factor secretion in an ovarian hyperstimulation syndrome (OHSS) animal model: implications for treatment of OHSS with dopamine receptor 2 agonists

To explore whether a dopamine receptor 2 agonist (D2-ag) can prevent ovarian hyperstimulation syndrome (OHSS) in a rat model by decreasing ovarian vascular endothelial growth factor (VEGF) production. Experimental study in an OHSS animal model. University-affiliated infertility center. Immature Wistar rats. Immature rats were stimulated with gonadotropins to mimic OHSS and treated with a D2-ag and/or D2-antagonists (D2-ant). Vascular permeability (VP) was measured at the endpoint, and ovaries were collected to assess the effects of these drugs on VEGF production. VP was estimated by measuring the peritoneal extravasation of a previously injected dye. Ovarian VEGF mRNA expression and VEGF protein levels were assessed by quantitative real-time PCR and Western blots, respectively. The D2-ag exerted a reduction in VP that was associated with a drastic decrease in VEGF protein production in OHSS rat ovaries. The effects of this D2-ag on VP and VEGF protein levels were partially reversed by concomitant administration of a D2-ant. Ovarian VEGF mRNA expression levels were unaffected by these drugs in OHSS rats. D2-ags prevent increased VP in OHSS rats by decreasing ovarian VEGF production, very likely through a D2-mediated post-transcriptional mechanism. Given the dose-dependent inhibitory effect of D2-ags on ovarian VEGF production reported herein, we infer that current OHSS therapies used in humans may be improved by increasing the intraovarian concentration of D2-ags in these patients.

O7.04 * DCE-MRI DISCRIMINATES BETWEEN RESPONDER AND NON-RESPONDER IN RECURRENT HIGH-GRADE GLIOMA PATIENTS UNDERGOING ANTI-ANGIOGENIC TREATMENT

OBJECTIVES: In this prospective phase II clinical study we analyzed whether dynamic contrast enhanced (DCE) MRI is able to distinguish between anti-vascular and anti-tumor effects in the course of anti-angiogenic treatment of recurrent high-grade glioma patients (rHGG). METHODS: Twenty-two patients with rHGG (16 glioblastoma, 5 anaplastic astrocytoma, 1 anaplastic oligoastrocytoma) were treated biweekly with bevacizumab/irinotecan. DCE-MRI scans were performed prior to (baseline) and eight weeks after treatment commencement. DCE-MRI analysis included four semiquantitative parameters, describing gadolinium contrast medium behavior: 1) initial slope of signal increase (marker for vessel permeability; slope), 2) maximum enhancement (marker for extravascular volume; ME), 3) time from starting of curve increase until ME (time-to-peak; TTP), 4) area under the curve until ME (AUC). Comparison of DCE parameters at baseline and follow-up was performed by Wilcoxon rank test. Responders to anti-angiogenic therapy were defined as having a progression free survival greater than 6 months. RESULTS: Mean PFS was 4.0 ± 2.2 months and 4 patients had a PFS greater than 6 months. At baseline there was no difference in ME, TTP, AUC and slope between responder and non-responder. At follow-up responders showed a significant decrease in ME, TTP and AUC, whereas slope did not change (mean ME 60.03% vs. 23.00%, mean TTP 579.5sec vs 367.4sec, mean AUC 55040 vs 12150, p < 0.001, respectively, slope 1.03 vs 1.04). In contrary, non-responder showed no change in ME, TTP and AUC but an increase in slope (mean ME 55.45% vs. 50.21%, mean TTP 539.0sec vs. 523.4sec, mean AUC 53440 vs. 50320 and slope 1.49 vs 1.74, p < 0.001). CONCLUSION: Semiquantitative DCE-MRI analysis may identify responders to anti-angiogenic therapy characterized by a significant decrease in extravascular volume despite lack of reduction in vascular permeability. These results may provide insights into anti-angiogenic treatment effects and serve as a new imaging biomarker in rHGG patients undergoing bevacizumab therapy.

Lung capillary injury and repair in left heart disease: a new target for therapy?

The lungs are the primary organs affected in LHD (left heart disease). Increased left atrial pressure leads to pulmonary alveolar-capillary stress failure, resulting in cycles of alveolar wall injury and repair. The reparative process causes the proliferation of MYFs (myofibroblasts) with fibrosis and extracellular matrix deposition, resulting in thickening of the alveolar wall. Although the resultant reduction in vascular permeability is initially protective against pulmonary oedema, the process becomes maladaptive causing a restrictive lung syndrome with impaired gas exchange. This pathological process may also contribute to PH (pulmonary hypertension) due to LHD. Few clinical trials have specifically evaluated lung structural remodelling and the effect of related therapies in LHD. Currently approved treatment for chronic HF (heart failure) may have direct beneficial effects on lung structural remodelling. In the future, novel therapies specifically targeting the remodelling processes may potentially be utilized. In the present review, we summarize data supporting the clinical importance and pathophysiological mechanisms of lung structural remodelling in LHD and propose that this pathophysiological process should be explored further in pre-clinical studies and future therapeutic trials.