• Biomolecules & Therapeutics
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• v.22 no.1
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• pp.1-9
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• 2014

Vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR) system has been shown to play central roles not only in physiological angiogenesis, but also in pathological angiogenesis in diseases such as cancer. Based on these findings, a variety of anti-angiogenic drugs, including anti-VEGF antibodies and VEGFR/multi-receptor kinase inhibitors have been developed and approved for the clinical use. While the clinical efficacy of these drugs has been clearly demonstrated in cancer patients, they have not been shown to be effective in curing cancer, suggesting that further improvement in their design is necessary. Abnormal expression of an endogenous VEGF-inhibitor sFlt-1 has been shown to be involved in a variety of diseases, such as preeclampsia and aged macular degeneration. In addition, various factors modulating angiogenic processes have been recently isolated. Given this complexity then, extensive studies on the interrelationship between VEGF signals and other angiogenesis-regulatory systems will be important for developing future strategies to suppress diseases with an angiogenic component.

• Biomolecules & Therapeutics
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• v.24 no.3
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• pp.260-267
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• 2016

Mesenchymal stem cells (MSCs) offer significant therapeutic promise for various regenerative therapies. However, MSC-based therapy for injury exhibits low efficacy due to the pathological environment in target tissues and the differences between in vitro and in vivo conditions. To address this issue, we developed adipose-derived MSC spheroids as a novel delivery method to preserve the stem cell microenvironment. MSC spheroids were generated by suspension culture for 3 days, and their sizes increased in a time-dependent manner. After re-attachment of MSC spheroids to the plastic dish, their adhesion capacity and morphology were not altered. MSC spheroids showed enhanced production of hypoxia-induced angiogenic cytokines such as vascular endothelial growth factor (VEGF), stromal cell derived factor (SDF), and hepatocyte growth factor (HGF). In addition, spheroid culture promoted the preservation of extracellular matrix (ECM) components, such as laminin and fibronectin, in a culture time- and spheroid size-dependent manner. Furthermore, phosphorylation of AKT, a cell survival signal, was significantly higher and the expression of pro-apoptotic molecules, poly (ADP ribose) polymerase-1 (PARP-1) and cleaved caspase-3, was markedly lower in the spheroids than in MSCs in monolayers. In the murine hindlimb ischemia model, transplanted MSC spheroids showed better proliferation than MSCs in monolayer. These findings suggest that MSC spheroids promote MSC bioactivities via secretion of angiogenic cytokines, preservation of ECM components, and regulation of apoptotic signals. Therefore, MSC spheroid-based cell therapy may serve as a simple and effective strategy for regenerative medicine.

• BMB Reports
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• v.39 no.5
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• pp.469-478
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• 2006

Vascular endothelial growth factor (VEGF)-A, a major regulator for angiogenesis, binds and activates two tyrosine kinase receptors, VEGFR1 (Flt-1) and VEGFR2 (KDR/Flk-1). These receptors regulate physiological as well as pathological angiogenesis. VEGFR2 has strong tyrosine kinase activity, and transduces the major signals for angiogenesis. However, unlike other representative tyrosine kinase receptors which use the Ras pathway, VEGFR2 mostly uses the Phospholipase-$C{\gamma}$-Protein kinase-C pathway to activate MAP-kinase and DNA synthesis. VEGFR2 is a direct signal transducer for pathological angiogenesis including cancer and diabetic retinopathy, thus, VEGFR2 itself and the signaling appear to be critical targets for the suppression of these diseases. VEGFR1 plays dual role, a negative role in angiogenesis in the embryo most likely by trapping VEGF-A, and a positive role in adulthood in a tyrosine kinase-dependent manner. VEGFR1 is expressed not only in endothelial cells but also in macrophage-lineage cells, and promotes tumor growth, metastasis, and inflammation. Furthermore, a soluble form of VEGFR1 was found to be present at abnormally high levels in the serum of preeclampsia patients, and induces proteinurea and renal dysfunction. Therefore, VEGFR1 is also an important target in the treatment of human diseases. Recently, the VEGFR2-specific ligand VEGF-E (Orf-VEGF) was extensively characterized. Interestingly, the activation of VEGFR2 via VEGF-E in vivo results in a strong angiogenic response in mice with minor side effects such as inflammation compared with VEGF-A, suggesting VEGF-E to be a novel material for pro-angiogenic therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1667-1674
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• 2012

Objective: To explore the differential protein expression profile in EC304 gastric cancer cells induced by alphastatin. Methods: Cultured EC304 cells in the exponential phase of growth were randomly divided into alphastatin and control groups. Total proteins were extracted and the two dimensional electrophoresis (2-DE) technique was applied to analyze differences in expression with ImageMaster 2D Platinum 5.0 software. Proteins were identified using the MASCOT database and selected differently expressed proteins were characterised by western blotting and immunofluorescence. Results: $1350{\pm}90$ protein spots were detected by the ImageMaster software in the 2-DE gel images from the control and alphastatin groups. The match rate was about 72-80% for the spectrum profiles, with 29 significantly different protein spots being identified, 10 upregulated, 16 downregulated, two new and one lost. The MASCOT search scores were 64-666 and the peptide matching numbers were 3-27 with sequence coverage of 8-62%. Twenty-three proteins were checked by mass spectrometry, including decrease in Nm23 and profilin-2 isoform b associated with the regulation of actin multimerisation induced by extracellular signals. Conclusion: The proteome in EC304 cells is dramatically altered by alphastatin, which appears to play an important role in modulating cellular activity and anti-angiogenesis by regulating protein expression and signal transduction pathways through Nm23 and profilin-2 isoform b, providing new research directions for anti-angiogenic therapy of gastric cancer.