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Aim To investigate the effects of isoliquiri-tigenin ( ISL) on anti-angiogenesis both in vitro and in vivo and its mechanisms. Methods We assessed the antiangiogenic activities of ISL on proliferation viabili-ty, migration and tube formation of human microvascu-lar endothelial cell line-1 (HMEC-1) in vitro. The cell proliferation viability was assessed using the Sulforho-damine B ( SRB ) assay. Modified Boyden Transwell chamber assay was done to study the effect of ISL on HMEC-1 cells migration. 2′, 7′-dichlorofluorescein di-acetate ( DCFH-DA) was used to measure the levels of intracellular reactive oxygen species ( ROS ) , which was induced by VEGF. Metalloproteinase-2 ( MMP-2 ) and metalloproteinase-9 ( MMP-9 ) expressions by HMEC-1 cells were assessed through gelatin zymogra-phy assay. HMEC-1 cells cycle was detected by flow cytometry. Moreover, we investigated the in vivo anti-angiogenic activity of ISL on chicken embryos nap al-lantoic membrane model ( CAM ) . Results ISL con-centration-dependently inhibited the growth of HMEC-1 cells as well as SW620 and A549 cells. ISL signifi-cantly and concentration-dependently suppressed the migration activity of HMEC-1 cells. Tube sample struc-ture formation further confirmed the effect of ISL on an-ti-angiogenesis. Moreover, ISL also inhibited intracel-lular ROS level, MMP-2 and MMP-9 expression by HMEC-1 cells. ISL induced endothelial cell apoptosis at a low concentration ( ISL 12 . 5 μmol · L-1 ) and blocked the cells in S phase of mitosis at higher con-centrations ( ISL 25~100 μmol·L-1 ) . Furthermore, ISL distinctly inhibited the angiogenesis of chick em-bryos in vivo. Conclusions ISL has anti-tumor and angiogenesis effects on HMEC-1 cells. The mechanism may be related to intracellular ROS scavenging and ap-optosis induction of HMEC-1 cells.
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Background: Immortalized human endothelial cells are widely used as in vitro models for debilitating conditions such as cancer, cardiovascular and ocular diseases. Human microvascular endothelial cell (HMEC-1) is immortalized via stable transfection with a gene encoding SV40 large antigen whilst telomerase-immortalized human microvascular endothelial (TIME) cells is immortalized by engineering the human telomerase catalytic protein (hTERT) into primary microvascular endothelial cells. Here, we established a three-dimensional (3D) spheroid invasion assay with HMEC-1 and TIME and compared the difference in their ability to invade through the collagen matrix in response to exogenous growth factors, namely vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Methods: TIME and HMEC-1 spheroids were embedded in a collagen matrix. The spheroids were stimulated with exogenous growth factors, namely VEGF (50ng/mL) and bFGF (200ng/mL). Twelve points of invasion length from a spheroid was measured using image analysis software, Image J. Three independent experiments were conducted and data was analysis by GraphPad Instat software, version 3.05. Results: TIME spheroid invasion was 16.5 fold higher with exogenous VEGF (50ng/mL) and bFGF (200ng/mL) treatment as compared to those cultured in complete growth medium only. In contrast, no significant difference was observed between HMEC-1 spheroids stimulated with and without exogenous growth factors, VEGF and bFGF. Conclusions: This is the first report on the establishment of a 3D-spheroid invasion assay with TIME cells. The requirement of VEGF and bFGF for TIME spheroids invasion is a novel finding. In addition, this assay offers an advantage over HMEC-1 for testing novel angiogenic agents since it is not affected by endogenously secreted growth factors.
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Aim To investigate the specificity of angiostatin to vascular endothelial cells. Methods S-180 tumor imaging and autoradiography of angiogenesis on Matrigel model was developed with 99 Tcm-recombinant human angiostatin ( 99 Tcm-rhAS) as a tracer, and FCM on human microvascular endothelial cell-1 (HMEC-1) with FITC-rhAS or rhAS antibody. The binding protein of rhAS on HMEC-1 was isolated by af-finity chromatography, and the proteins was sequenced with MS. Results 99 Tcm-rhAS was concentrated on the tumor site in vivo, and the rhAS was specific to angiogenesis of tumor. There were some binding sites on the surface of HMEC-1. Three proteins which are able to bind rhAS were obtained by affinity chromatography, among which tubulin sequenced was an important target for tumor. Conclusion The angiostatin is specific to novel vascular endothelial cell, and its mechanism targeting tumor is complicated.