semaxinib and Brain-Neoplasms

Topics: Adult; Angiogenesis Inhibitors; Brain Neoplasms; Female; Hemangioblastoma; Humans; Indoles; Male; Middle Aged; Pyrroles; Retinal Neoplasms; Spinal Cord Neoplasms; Treatment Outcome; Vascular Endothelial Growth Factor A; von Hippel-Lindau Disease

Neovascularization and invasion are key features of malignant gliomas. Matrix metalloproteinases (MMPs) are supposed to play a major role mediating these processes. To analyze the expression patterns of MMPs in microvascular human cerebral endothelial cells (HCEC), we isolated endothelial cells from normal human brain microvessels. Characterization of cellular origin was performed by immunostaining, using the endothelial cell markers Ulex europaeus Agglutinin-1, von-Willebrand-Factor and Glucose-transporter-1. Contamination by other cell types was tracked by immunohistochemistry for GFAP (astrocytes), ASM (pericytes) and CD68 (macrophages). Secretion of MMPs was evaluated by ELISA and zymography. To determine whether HCEC show any difference in MMP expression compared to endothelial cells of other origin we analyzed human umbilical vein endothelial cells (HUVEC). HCEC show a decrease of MMP-3 and MMP-2 protein when treated with SU5416, a VEGF-R2 (KDR/flk-1) inhibitor, whereas MMP expression remained unchanged in HUVEC. To determine whether these findings show any effect in the motility of these cells we used a three-dimensional co-culture assay of avascular glioblastoma spheroids with primary HCEC spheroids. Untreated controls showed invasion of both cell populations into each other whereas treatment of the co-cultures with SU5416 resulted in complete inhibition of endothelial cell invasion hence indicating that flk-1 related motility of endothelial cells is critically involved in this process and can be studied with this assay. The results of different effects of anti-angiogenic treatment on proteolytic properties of two endothelial cell populations suggest that neovascularization of human brain tumors in vitro is dependent on the surrounding endothelial cell type and should therefore be studied with organ-specific human microvascular cerebral endothelial cells.

Topics: Angiogenesis Inhibitors; Brain Neoplasms; Cell Movement; Cerebral Cortex; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Glioblastoma; Humans; Immunoenzyme Techniques; In Vitro Techniques; Indoles; Interleukin-10; Matrix Metalloproteinases; Microcirculation; Neovascularization, Pathologic; Protein-Tyrosine Kinases; Pyrroles; Spheroids, Cellular; Tumor Cells, Cultured; Umbilical Veins; Vascular Endothelial Growth Factor Receptor-2

Human low-grade gliomas represent a population of brain tumors that remain a therapeutic challenge. Preclinical evaluation of agents, to test their preventive or therapeutic efficacy in these tumors, requires the use of animal models. Spontaneous gliomas develop in models of chemically induced carcinogenesis, such as in the transplacental N-ethyl-N-nitrosourea (ENU) rat model. However, without the ability to detect initial tumor formation, multiplicity or to measure growth rates, it is difficult to test compounds for their interventional or preventional capabilities. In this study Fisher-334 rats, treated transplacentally with ENU, underwent magnetic resonance imaging (MRI) examination in order to evaluate this approach for detection of tumor formation and growth. ENU-induced intracranial cerebral tumors were first observable in T2-weighted images beginning at 4 months of age and grew with a mean doubling time of 0.487 +/- 0.112 months. These tumors were found histologically to be predominately mixed gliomas. Two therapeutic interventions were evaluated using MRI, vitamin A (all-trans retinol palmitate, RP), as a chemopreventative agent and the anti-angiogenic drug SU-5416. RP was found to significantly delay the time to first tumor observation by one month (P = 0.05). No differences in rates of tumor formation or growth rates were observed between control and RP-treated groups. MRI studies of rats treated with SU-5416 resulted in reduction in tumor growth rates compared to matched controls. These results show that MRI can be used to provide novel information relating to the therapeutic efficacy of agents against the ENU-induced tumor model.

Topics: Angiogenesis Inhibitors; Animals; Brain Neoplasms; Carcinogens; Diet; Disease Models, Animal; Diterpenes; Ethylnitrosourea; Glioma; Indoles; Magnetic Resonance Imaging; Neoplasms, Multiple Primary; Neoplasms, Second Primary; Pyrroles; Rats; Rats, Inbred F344; Receptor Protein-Tyrosine Kinases; Receptors, Growth Factor; Receptors, Vascular Endothelial Growth Factor; Retinyl Esters; Survival Analysis; Time Factors; Vitamin A

Accumulating evidences suggest that tumor growth and metastasis depend on angiogenesis. At present, plenty of efforts are made to discover a chemical compound that specifically inhibits tumor angiogenesis either by reducing pro-angiogenic factor or increasing anti-angiogenic factors.. SU5416, a novel, synthetic, potential inhibitor of angiogenesis specifically blocks the Flk-1/KDR tyrosine kinase activity. In vivo effect of SU5416 in the treatment of intracranial tumors has not been previously described.. We transplanted GS-9L cells into the right caudate nucleus of male Fisher 344 rats and administrated SU5416 intraperitoneally (i.p.) to investigate the impact of SU5416 on tumor angiogenesis and growth in vivo. Starting on Day 1 or Day 8, forty-two animals were treated with SU5416 at three different doses (e.g. 12.5, 25.0 and 50.0 mg/kg body weight) via i.p. injection every day until the end-point. As a control, seven animals received no treatment and after implant fourteen animals were treated with vehicle (DMSO) only.. SU5416 prolonged the survival in the treated groups without any significant systemic adverse effect. Median survival in the treated group started on Day.1 was statistically longer compared to that in the control groups (p<0.01). Histological analysis of the treated tumors showed an increase in necroses and reduced in vascularity compared to the control tumors. Furthermore, the number of apoptotic cells increased in the treated tumors on a TUNEL stain.. Small molecular compounds, such as SU5416 may be useful therapeutics that specifically inhibits the enzymatic activity of Flk-1 kinase and downstream events of tumor angiogenesis.

Topics: Animals; Apoptosis; Brain; Brain Neoplasms; Enzyme Inhibitors; Glioma; Indoles; Male; Microcirculation; Pyrroles; Rats; Rats, Inbred F344; Receptor Protein-Tyrosine Kinases; Receptors, Growth Factor; Receptors, Vascular Endothelial Growth Factor; Survival Rate