Cardiovascular response to small-molecule APJ activation

Heart failure (HF) remains a grievous illness with poor prognosis even with optimal care. The apelin receptor (APJ) counteracts the pressor effect of angiotensin II, attenuates ischemic injury, and has the potential to be a novel target to treat HF. Intravenous administration of apelin improves cardiac function acutely in patients with HF. However, its short half-life restricts its use to infusion therapy. To identify a longer acting APJ agonist, we conducted a medicinal chemistry campaign, leading to the discovery of potent small-molecule APJ agonists with comparable activity to apelin by mimicking the C-terminal portion of apelin-13. Acute infusion increased systolic function and reduced systemic vascular resistance in 2 rat models of impaired cardiac function. Similar results were obtained in an anesthetized but not a conscious canine HF model. Chronic oral dosing in a rat myocardial infarction model reduced myocardial collagen content and improved diastolic function to a similar extent as losartan, a RAS antagonist standard-of-care therapy, but lacked additivity with coadministration. Collectively, this work demonstrates the feasibility of developing clinical, viable, potent small-molecule agonists that mimic the endogenous APJ ligand with more favorable drug-like properties and highlights potential limitations for APJ agonism for this indication.

Abstract 4566: OncoVEXmGM-CSF (HSV-1 modified similarly to Talimogene Laherparepvec) in combination with CTLA-4 blockade leads to both local and systemic efficacy in a murine syngeneic model of metastatic melanoma

Talimogene laherparepvec is an oncolytic immunotherapy based on a modified herpes simplex virus type 1 (HSV-1) designed to kill cancer cells through two mechanisms: a) direct viral-mediated lysis and b) stimulation of a tumor antigen-specific adaptive immune response. We developed a mouse model of metastatic melanoma using the B16F10 cell line to study local and systemic responses following treatment with talimogene laherparepvec alone or in combination with CTLA-4 blockade. OncoVEXmGM-CSF, an HSV-1 modified similarly to talimogene laherparepvec (murine GM-CSF is expressed instead of human GM-CSF) was used in these studies.

B16F10 cells have been reported to be resistant to HSV-1 infection due to a lack of requisite entry receptors. To overcome resistance, we transduced B16F10 cells with a lentiviral vector expressing mouse nectin1 (mNectin1) or eGFP as a control. Expression was confirmed by ddPCR and sensitivity to OncoVEXmGM-CSF evaluated in an in vitro viability assay. B16F10-mNectin1 cells were highly sensitive to OncoVEXmGM-CSF with a multiplicity of infection (MOI) IC50 of 0.001 (B16F10-eGFP were insensitive at MOI of 100). In vivo, B16F10-mNectin1 and B16F10-eGFP cells showed similar growth when injected subcutaneously. OncoVEXmGM-CSF treatment of B16F10-mNectin1 tumors (intratumoral, 5x106 PFU/dose, 3X) caused a significant (p<0.0001) inhibition of tumor growth and prolonged median overall survival compared to control animals. To assess the local and systemic effect of OncoVEXmGM-CSF in combination with CTLA-4 blockade, we developed a model of experimental metastatic melanoma by delivering the B16F10-eGFP cells intravenously (systemic, non-injectable tumors) on day 0 and implanting the B16F10-mNectin1 cells SC (local, injectable tumors) on day 2. Mice were dosed with OncoVEXmGM-CSF and anti-CTLA-4 antibody 9D9 (100ug/dose) every 3 days between days 12 and 19. Subcutaneous tumor growth inhibition was assessed and lung metastasis were quantified on day 28. Both OncoVEXmGM-CSF and CTLA-4 treatment significantly inhibited subcutaneous tumor growth and lung metastasis. The combination of both therapeutics resulted in significantly greater local and systemic efficacy than either agent alone. The strong local and systemic anti-tumor activity of the combination resulted in a significant increase in median overall survival (p<0.0001) compared to control mice that received intravenous B16F10-eGFP cells only.

In conclusion, OncoVEXmGM-CSF in combination with CTLA-4 blockade significantly reduced systemic tumor burden and prolonged median overall survival in a B16F10 mouse model of metastatic melanoma. These data support the proposed MOA by which OncoVEXmGM-CSF treatment can cause direct tumor lysis along with potentiation of an adaptive, systemic anti-tumor immune response.

Citation Format: Keegan Cooke, Juan Estrada, Jinghui Zhan, David Hill, Andrea Boden, Jon Werner, Pedro J. Beltran. OncoVEXmGM-CSF (HSV-1 modified similarly to Talimogene Laherparepvec) in combination with CTLA-4 blockade leads to both local and systemic efficacy in a murine syngeneic model of metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4566. doi:10.1158/1538-7445.AM2017-4566

High-Energy Electron and Proton Irradiation of Cu(In,Ga)Se2 Heterojunction Solar Cells

We investigate radiation-induced defects in high-efficiency Cu(In,Ga)Se2/CdS/ZnO heterojunction solar cells after 1-MeV electron and 4-MeV proton irradiation. We use electron and proton fluences of more than 1018 cm−2 and up to 1014 cm−2, respectively. The irradiation experiments performed at three independent electron irradiation facilities consistently prove the superior radiation resistance of these Cu(In,Ga)Se2 devices compared to other types of solar cells. The reduction of the solar cell efficiency in all experiments is predominantly caused by a loss ΔVOC of the open circuit voltage VOC. An analytical model describes ΔVOC in terms of radiation-induced defects enhancing recombination in the Cu(In,Ga)Se2 absorber material. From our model we extract the defect introduction rates for recombination centers in Cu(In,Ga)Se2 for the respective particles and energies. Isochronal annealing steps fully recover VOC of the irradiated Cu(In,Ga)Se2 solar cells. Exposure to temperatures of approx. 400 K are sufficient to restore the initial VOC within less than 5 %, even after excessive irradiation. The annealing process displays an activation energy of EA = 1.1 eV. Admittance spectroscopy directly reveals the generation and the annealing of radiation-induced defects.

Platelet concentrates transfusion in cardiac surgery and platelet function assessment by multiple electrode aggregometry

BACKGROUND

Platelet dysfunction contributes to the pathophysiology of bleeding complications during and after cardiac surgery. In most surgical institutions, no peri-operative point-of-care monitoring of platelet function is used. We evaluated the usefulness of the Multiplate platelet function analyser based on impedance aggregometry for identifying groups of patients at a high risk of transfusion of platelet concentrates (PC).

METHODS

Platelet function parameters were determined in 60 patients before and after routine cardiac surgery. Impedance aggregometry measurements were performed on Multiplate using ADP (ADPtest), collagen (COLtest) and thrombin receptor activating peptide (TRAPtest) as platelet activators. The correlations between the aggregometry results and the transfusion of PC were calculated. The results of the aggregation tests were also divided into tertiles and the differences in PC transfusion between the low and the high tertile were assessed.

RESULTS

Low aggregometry delimited groups of patients with significantly higher PC transfusion. In the receiver operating characteristic curve, low pre-operative aggregation in the ADPtest identified patients with high total transfusion of PC (area under the curve 0.74, P=0.001), while the ADPtest performed at the end of the operation identified patients with high PC transfusion on the intensive care unit (ICU) (area under the curve 0.76, P=0.002).

CONCLUSIONS

Near-patient platelet aggregation may allow the identification of patients with enhanced risk of PC transfusion, both pre-operatively and upon arrival on the ICU.