PEGylated Recombinant Ink Toxin Depletes Arginine and Lysine and Inhibits the Growth of Tumor Xenografts.

In recent years, a novel treatment method for cancer has emerged, which is based on the starvation of tumors of amino acids like arginine. The deprivation of arginine in serum is based on enzymatic degradation and can be realized by arginine deaminases like the l-amino acid oxidase found in the ink toxin of the sea hare . Previously isolated from the ink, the l-amino acid oxidase was described to oxidate the essential amino acids l-lysine and l-arginine to their corresponding deaminated alpha-keto acids.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Macimorelin in Children with Suspected Growth Hormone Deficiency: An Open-Label, Group Comparison, Dose-Escalation Trial.

Background/aims: Diagnosis of growth hormone deficiency (GHD) in children requires the use of provocative growth hormone (GH) stimulation tests, which can have limited reliability and are potentially contraindicated in some patients. This is the first paediatric study to test the safety, tolerability, and pharmacokinetics (PK)/pharmacodynamics (PD) of macimorelin, an oral GH secretagogue, approved for diagnosis of adult GHD.

Methods: In this open-label, group comparison, single-dose escalation trial (EudraCT 2018-001988-23), sequential cohorts of patients (C1-C3) received ascending single doses of macimorelin: 0.

A physiologically based pharmacokinetic (PBPK) parent-metabolite model of the chemotherapeutic zoptarelin doxorubicin-integration of in vitro results, Phase I and Phase II data and model application for drug-drug interaction potential analysis.

Purpose: Zoptarelin doxorubicin is a fusion molecule of the chemotherapeutic doxorubicin and a luteinizing hormone-releasing hormone receptor (LHRHR) agonist, designed for drug targeting to LHRHR positive tumors. The aim of this study was to establish a physiologically based pharmacokinetic (PBPK) parent-metabolite model of zoptarelin doxorubicin and to apply it for drug-drug interaction (DDI) potential analysis.

Methods: The PBPK model was built in a two-step procedure.

New ligands of the ghrelin receptor based on the 1,2,4-triazole scaffold by introduction of a second chiral center.

Introducing a second chiral center on our previously described 1,2,4-triazole, allowed us to increase diversity and elongate the 'C-terminal part' of the molecule. Therefore, we were able to explore mimics of the substance P analogs described as inverse agonists. Some compounds presented affinities in the nanomolar range and potent biological activities, while one exhibited a partial inverse agonist behavior similar to a Substance P analog.

New trisubstituted 1,2,4-triazoles as ghrelin receptor antagonists.

Ghrelin receptor ligands based on a trisubstituted 1,2,4-triazole scaffold were recently synthesized and evaluated for their in vitro affinity for the GHS-R1a receptor and their biological activity. In this study, replacement of the α-aminoisobutyryl (Aib) moiety (a common feature present in numerous growth hormone secretagogues described in the literature) by aromatic and heteroaromatic groups was explored. We found potent antagonists incorporating the picolinic moiety in place of the Aib moiety.

Discovery of (7-aryl-1,5-naphthyridin-2-yl)ureas as dual inhibitors of ERK2 and Aurora B kinases with antiproliferative activity against cancer cells.

A novel series of (7-aryl-1,5-naphthyridin-2-yl)ureas was discovered as dual ERK2 and Aurora B kinases inhibitors. Several analogues were active at micromolar and submicromolar range against ERK2 and Aurora B, associated with very promising antiproliferative activity toward various cancer cell lines. Synthesis, structure activity relationship and docking study are reported.

Current view on the mechanism of action of perifosine in cancer.

Perifosine treatment exhibits a complex molecular response including the inhibition of Akt or the induction of apoptosis via clustering of death receptors in lipid rafts. However, the molecular response can vary between different tumor entities and the contribution of each target pathway to the activity of Perifosine might be distinct depending on the tumor entity or the agent combined with Perifosine. In this review we discuss the current view on the mechanism of action of perifosine in cancer and the contribution of the molecular targets of Perifosine to its activity.

Discovery of 7-aryl-substituted (1,5-naphthyridin-4-yl)ureas as aurora kinase inhibitors.

As part of our research projects to identify new chemical entities of biological interest, we developed a synthetic approach and the biological evaluation of (7-aryl-1,5-naphthyridin-4-yl)ureas as a novel class of Aurora kinase inhibitors for the treatment of malignant diseases based on pathological cell proliferation. 1,5-Naphthyridine derivatives showed excellent inhibitory activities toward Aurora kinases A and B, and the most active compound, 1-cyclopropyl-3-[7-(1-methyl-1H-pyrazol-4-yl)-1,5-naphthyridin-4-yl]urea (49), displayed IC₅₀ values of 13 and 107 nM against Aurora kinases A and B, respectively. In addition, the selectivity toward a panel of seven cancer-related protein kinases was highlighted.

Paclitaxel encapsulated in cationic liposomes: a new option for neovascular targeting for the treatment of prostate cancer.

Neovascular targeting is an established approach for the therapy of prostate cancer (PCa). Cationic liposomes have been shown to be absorbed by immature vascular endothelial cells due to negative electric charge of their outer cell membrane. We aimed to evaluate the antitumoural efficacy of paclitaxel encapsulated in cationic liposomes for the treatment of PCa.

Paclitaxel encapsulated in cationic liposomes increases tumor microvessel leakiness and improves therapeutic efficacy in combination with Cisplatin.

Purpose: Paclitaxel encapsulated in cationic liposomes (EndoTAG-1) is a vascular targeting formulation for the treatment of solid tumors. It triggers intratumoral microthrombosis, causing significant inhibition of tumor perfusion and tumor growth associated with endothelial cell apoptosis. Here, we quantified the effects of repeated EndoTAG-1 therapy on tumor microvascular leakiness with respect to leukocyte-endothelial cell interactions, the targeting property of cationic liposomes, and the therapeutic combination with conventional cisplatin chemotherapy.

Tumor-selective vessel occlusions by platelets after vascular targeting chemotherapy using paclitaxel encapsulated in cationic liposomes.

Paclitaxel encapsulated in cationic liposomes (EndoTAG-1) significantly impairs tumor growth by a significant reduction of functional tumor microcirculation and induction of endothelial cell apoptosis. The aim of the study was to analyze whether platelet activation within the tumor microcirculation contributes to the antivascular effects of vascular targeting chemotherapy using EndoTAG-1. In vitro, FACS analysis revealed a significant activation of platelets upon treatment with EndoTAG-1.

Cationic lipid complexed camptothecin (EndoTAG-2) improves antitumoral efficacy by tumor vascular targeting.

Neo-vascular targeting by cationic colloidal carriers enables to realize an innovative approach for tumor therapy. EndoTag-2 is a novel vascular targeting agent, comprising the mammalian topoisomerase I inhibitor camptothecin in its carboxylate form complexed to cationic lipid (cationic lipid complexed camptothecin). Here we studied tumor vascular targeting properties, antitumoral effects and mode of action of EndoTag-2.

Paclitaxel encapsulated in cationic lipid complexes (MBT-0206) impairs functional tumor vascular properties as detected by dynamic contrast enhanced magnetic resonance imaging.

Cationic lipid complexes have been shown to be bound and internalized selectively by angiogenic tumor endothelial cells after intravenous injection. Based on this phenomenon, the chemotherapeutic agent paclitaxel was encapsulated into these lipid complexes providing a vascular targeting agent (MBT-0206). As noninvasive imaging techniques are of critical importance for optimizing antivascular cancer treatment in the clinic, we have evaluated the antivascular effects of MBT-0206 in the A-MEL-3 solid tumor model using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI).

Morphology and transfection study of human microvascular endothelial cell angiogenesis: an in vitro three-dimensional model.

Microvascular endothelial cells from human neonatal foreskin were grown in vitro until a three-dimensional network of capillary-like structures was formed. All stages of the angiogenic cascade could be observed in this in vitro model, including the formation of an internal lumen. The microscopy focused on morphology, formation of an internal lumen, role of the extracellular matrix, polarity of the cells, and the time-course of the angiogenic cascade.

Protamine enhances uptake of cationic liposomes in angiogenic microvessels.

Introduction: Cationic liposomes have been shown to target angiogenic endothelial cells of solid tumours. Supposing a charge-related mechanism might be responsible for liposome-endothelial interaction, we investigated the effect of intravenous pre-injection of the charged molecules protamine, a polycationic protein, and fucoidan, a polyanionic polysaccharide on the accumulation of cationic liposomes within the blood vessels of a solid tumour.

Materials And Methods: Experiments were performed using the amelanotic hamster melanoma A-Mel-3 growing in a dorsal skinfold chamber of hamsters.

Neovascular targeting chemotherapy: encapsulation of paclitaxel in cationic liposomes impairs functional tumor microvasculature.

Cationic liposomes have been shown to be internalized selectively by angiogenic tumor endothelial cells after intravenous injection. Therefore, encapsulation of cytotoxic substances in cationic liposomes is a new approach to target tumor vasculature. It was the aim of our study to quantify the effects of paclitaxel encapsulated in cationic liposomes (MBT-0206) on tumor microvasculature and growth in vivo.

Neovascular targeting therapy: paclitaxel encapsulated in cationic liposomes improves antitumoral efficacy.

Purpose: Cationic liposomes have been shown to selectively target tumor endothelial cells. Therefore, the encapsulation of antineoplastic drugs into cationic liposomes is a promising tool to improve selective drug delivery by targeting tumor vasculature. It was the aim of our study to evaluate tumor selectivity and antitumoral efficacy of paclitaxel encapsulated in cationic liposomes in comparison with the free drug paclitaxel (Taxol(R)) in vivo.

Effect of the surface charge of liposomes on their uptake by angiogenic tumor vessels.

Recently, cationic liposomes have been shown to preferentially target the angiogenic endothelium of tumors. It was the aim of our study to investigate the influence of liposomal surface charge on the uptake and kinetics of liposomes into solid tumors and tumor vasculature. Experiments were performed in the amelanotic hamster melanoma A-Mel-3 growing in the dorsal skinfold chamber preparation of male Syrian golden hamsters.

Paclitaxel encapsulated in cationic liposomes diminishes tumor angiogenesis and melanoma growth in a "humanized" SCID mouse model.

Paclitaxel is an alkaloid that inhibits endothelial cell proliferation, motility, and tube formation at nanomolar concentrations. Cationic liposome preparations have been shown to target blood vessels. We wished to explore the possibility that paclitaxel encapsulated in cationic liposomes carries paclitaxel to blood vessels and thereby provides an antiangiogenic effect.

Immortalization of human corneal endothelial cells using electroporation protocol optimized for human corneal endothelial and human retinal pigment epithelial cells.

Purpose: In this study we established a protocol for transfection of human corneal endothelial and human retinal pigment epithelial cells. This protocol was used for immortalization of human corneal endothelial cells.

Methods: Transfection was performed by means of electroporation.

Establishment of a human placental endothelial cell line with extended life span after transfection with SV 40 T-antigens.

Studies utilizing microvascular human endothelial cells are relatively few because of substantial difficulties in isolation and cultivation, respective limited proliferation capability and functional variation of primary cells. To facilitate the closer examination of capillary endothelial characteristics, we isolated microvascular endothelial cells from full-term placenta and transfected the cells via lipofection with pRNS-1, encoding for the small and large T-antigens of SV 40. One cell line, HPEC-A1, with a largely extended life span was isolated and kept in culture for up to 80 cumulative population doublings.

Optimization of transfection of human endothelial cells.

Recently developed transfection methods for mammalian cells provide a powerful means for the study of gene function. Unfortunately, human endothelial cells were relative refractory to the classic transfection techniques. In this study we compared the usability of calcium phosphate, DEAE-dextran transfection, transferrinfection, lipofection, and electroporation for the transfection of early passage HUVECs and for the human endothelial cell lines ECV 304 and EA.

Establishment of the permanent microvascular endothelial cell line PBMEC/C1-2 from porcine brains.

Porcine brain microvascular endothelial cells (PBMEC) were isolated from fresh brains by several enzymatic digestion steps followed by a gradient centrifugation. Cells of the primary culture were transfected with pRNS-1, encoding for the small and large T-antigens of SV 40, by means of lipofection. After selection with G-418, clones were isolated and one clone, PBMEC/C1-2, was further characterized by microscopic examination of morphology, immunofluorescence, and lectin binding.

New lipid mixture for efficient lipid-mediated transfection of BHK cells.

A crude fraction of soybean lipids (azolectin) proved to be an inexpensive and effective substitute for highly purified phosphatidylethanolamine in preparation of phospholipid/dimethyldioctadecyl-ammonium bromide liposomes. Furthermore, directly suspending the components in aqueous buffer was superior to first dissolving the lipids in CHCl3.