AIM: To investigate the effect and mechanism of blockade of the CXC chemokine receptor-4 (CXCR4) signaling pathway by AMD3100, a small non-peptide CXCR4 inhibitor, on invasion and metastasis of colorectal cancer cells...AIM: To investigate the effect and mechanism of blockade of the CXC chemokine receptor-4 (CXCR4) signaling pathway by AMD3100, a small non-peptide CXCR4 inhibitor, on invasion and metastasis of colorectal cancer cells in vitro. METHODS: Human colorectal cancer cell line SW480 was treated with AMD3100 at different final concentrations. 3-(4,5-dimethylthiazole-2-yl)-2.5-dipheny-ltetrazolium bromide (MTT) assay was used to detect the effect of AMD3100 on cell proliferation. The invasion ability of SW480 cells was determined by cell invasion assay kit. In the presence of AMD3100, the CXCL12-mediated migratory response of SW480 cells was tested by classical chemotaxis assays. RT-PCR analysis and Western blotting were used to detect the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in SW480 cells. RESULTS: Cell viability was significantly suppressed by AMD3100 in a dose-dependent manner. AMD3100 (100 and 1000 ng/mL) significantly inhibited the invasion ability of SW480 cells. Treatment with AMD3100 markedly reduced the expression of VEGF and MMP-9 but not MMP-2 in SW480 cells. CONCLUSION: The CXCL12/CXCR4 system is an important mediator of proliferation and invasion of CXCR4-expressing colorectal cancer cells. AMD3100 inhibited invasion and metastasis activity of the colorectalcancer cell line SW480 through down-regulation of VEGF and MMP-9 expression.展开更多
AIM： To investigate the inhibitory effect of natural taurine （NTau） on portal hypertension （PHT） in rats with experimentally-induced liver cirrhosis （LC）. METHODS： Experimentally-induced LC Wistar rats （20 ra...AIM： To investigate the inhibitory effect of natural taurine （NTau） on portal hypertension （PHT） in rats with experimentally-induced liver cirrhosis （LC）. METHODS： Experimentally-induced LC Wistar rats （20 rats/group） were treated with either oral saline or oral NTau for 6 consecutive weeks. Evaluation parameters included portal venous pressure （PVP）, portal venous resistance （PVR）, portal venous flow （PVF）, splanchnic vascular resistance （SVR） and mean arterial pressure （NAP）. Vasoactive substance levels including nitric oxide （NO）, nitric oxide synthase （NOS） and cyclic guanosine monophosphate （cGMP） were also measured. Histological investigation of type Ⅰ and Ⅲ collagen （COL Ⅰ and Ⅲ） and transforming growth factor-β1 （TGF-β1） was also performed. RESULTS： Treatment with NTau （1） significantly decreased PVP, PVR and PVF, and increased MAP and SVP; （2） markedly increased the vascular compliance and reduced the zero-stress of the portal vein; （3） markedly decreased the amount of NO and cGMP and activity of NOS; and （4） improved the pathological status of the liver tissue and reduced the expression of COL Ⅰ, COL Ⅲ and TGF-β1. CONCLUSION： NTau inhibited the LC-induced PHT by improving hyperdynamic circulation, morphology of liver and biomechanical properties of the portal vein in experimentally-induced LC rats.展开更多
AIM:To investigate the effects of curcumin on the expression of peroxisome proliferator-activated receptorδ(PPARδ)and related genes in HT-29 cells. METHODS:HT-29 cells were treated with curcumin (0-80μmol/L)for 24 ...AIM:To investigate the effects of curcumin on the expression of peroxisome proliferator-activated receptorδ(PPARδ)and related genes in HT-29 cells. METHODS:HT-29 cells were treated with curcumin (0-80μmol/L)for 24 h.The effects of curcumin on the morphology of HT-29 cells were studied by Hoechst 33342 staining.The activity of caspase-3 was determined using DEVD-p NA as substrate.The levels of peroxisome PPARδ,14-3-3εand vascular endothelial growth factor(VEGF)in HT-29 cells were determined by Western blotting analysis and their mRNA expression was determined by real-time quantitative RT-PCR. RESULTS:Treatment with 10-80μmol/L curcumin induced typical features of apoptosis and activated the caspase-3 in HT-29 cells.The expression of PPARδ, 14-3-3εand VEGF was reduced and the activity of β-catenin/Tcf-4 signaling was inhibited by curcumin treatment. CONCLUSION:Curcumin can induce apoptosis of HT-29 cells and down-regulate the expression of PPARδ,14-3-3εand VEGF in HT-29.展开更多
The paper describes the expression of human protein VEGF165 in Escherichia coli and its purification. This growth factor isoform contains exon 7, which is essential for binding to extracellular domain of VEGF receptor...The paper describes the expression of human protein VEGF165 in Escherichia coli and its purification. This growth factor isoform contains exon 7, which is essential for binding to extracellular domain of VEGF receptor 2, located on endothelial cells lining the surface of blood vessels. This binding stimulates the cascade of downstream signalling events leading to process known as angiogenesis, hVEGF165 overexpressed with His-tag in BL21 E. coli cells forms inclusion bodies （insoluble protein）, so the research found the procedure for its solubilization and purification on a Nickel based affinity chromatography. Although this eukaryotic signal protein needs posttranslational processing for its full function as a homodimer, author verified the biological activity of our hVEGF165 protein, obtained as monomer, by wound healing test.展开更多
The tyrosine kinase receptor vascular endothelial growth factor receptor 2 （VEG FR2） is a key regulator of angiogenesis. Here we show that VEGFR2 is acetylated in endothelial cells both at four lysine residues formi...The tyrosine kinase receptor vascular endothelial growth factor receptor 2 （VEG FR2） is a key regulator of angiogenesis. Here we show that VEGFR2 is acetylated in endothelial cells both at four lysine residues forming a dense cluster in the kinase insert domain and at a single lysine located in the receptor activation loop. These modifications are under dynamic control of the acetyltransferase p300 and two deacetyiases HDAC5 and HDAC6. We demonstrate that VEGFR2 acetylation essentially regulates receptor phosphorylation. In par- ticular, VEGFR2 acetylation significantly alters the kinetics of receptor phosphorylation after ligand binding, allowing receptor phos- phoryiation and intraceUular signaling upon proLonged stimulation with VEGF. Molecular dynamics simulations indicate that acetylation of the lysine in the activation loop contributes to the transition to an open active state, in which tyrosine phosphorylation is favored by better exposure of the kinase target residues. These findings indicate that post-translational modification by acetyiation is a critical mechanism that directLy affects VEGFR2 function.展开更多
文摘AIM: To investigate the effect and mechanism of blockade of the CXC chemokine receptor-4 (CXCR4) signaling pathway by AMD3100, a small non-peptide CXCR4 inhibitor, on invasion and metastasis of colorectal cancer cells in vitro. METHODS: Human colorectal cancer cell line SW480 was treated with AMD3100 at different final concentrations. 3-(4,5-dimethylthiazole-2-yl)-2.5-dipheny-ltetrazolium bromide (MTT) assay was used to detect the effect of AMD3100 on cell proliferation. The invasion ability of SW480 cells was determined by cell invasion assay kit. In the presence of AMD3100, the CXCL12-mediated migratory response of SW480 cells was tested by classical chemotaxis assays. RT-PCR analysis and Western blotting were used to detect the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in SW480 cells. RESULTS: Cell viability was significantly suppressed by AMD3100 in a dose-dependent manner. AMD3100 (100 and 1000 ng/mL) significantly inhibited the invasion ability of SW480 cells. Treatment with AMD3100 markedly reduced the expression of VEGF and MMP-9 but not MMP-2 in SW480 cells. CONCLUSION: The CXCL12/CXCR4 system is an important mediator of proliferation and invasion of CXCR4-expressing colorectal cancer cells. AMD3100 inhibited invasion and metastasis activity of the colorectalcancer cell line SW480 through down-regulation of VEGF and MMP-9 expression.
基金Supported by The National Natural Science Foundation of China,Grant,No.30660235Guangxi Science Foundation forYouths,Grant,No.0728080National"11th 5-year"Support Plan of China,Grant,No.2006BAI0802-07
文摘AIM： To investigate the inhibitory effect of natural taurine （NTau） on portal hypertension （PHT） in rats with experimentally-induced liver cirrhosis （LC）. METHODS： Experimentally-induced LC Wistar rats （20 rats/group） were treated with either oral saline or oral NTau for 6 consecutive weeks. Evaluation parameters included portal venous pressure （PVP）, portal venous resistance （PVR）, portal venous flow （PVF）, splanchnic vascular resistance （SVR） and mean arterial pressure （NAP）. Vasoactive substance levels including nitric oxide （NO）, nitric oxide synthase （NOS） and cyclic guanosine monophosphate （cGMP） were also measured. Histological investigation of type Ⅰ and Ⅲ collagen （COL Ⅰ and Ⅲ） and transforming growth factor-β1 （TGF-β1） was also performed. RESULTS： Treatment with NTau （1） significantly decreased PVP, PVR and PVF, and increased MAP and SVP; （2） markedly increased the vascular compliance and reduced the zero-stress of the portal vein; （3） markedly decreased the amount of NO and cGMP and activity of NOS; and （4） improved the pathological status of the liver tissue and reduced the expression of COL Ⅰ, COL Ⅲ and TGF-β1. CONCLUSION： NTau inhibited the LC-induced PHT by improving hyperdynamic circulation, morphology of liver and biomechanical properties of the portal vein in experimentally-induced LC rats.
文摘AIM:To investigate the effects of curcumin on the expression of peroxisome proliferator-activated receptorδ(PPARδ)and related genes in HT-29 cells. METHODS:HT-29 cells were treated with curcumin (0-80μmol/L)for 24 h.The effects of curcumin on the morphology of HT-29 cells were studied by Hoechst 33342 staining.The activity of caspase-3 was determined using DEVD-p NA as substrate.The levels of peroxisome PPARδ,14-3-3εand vascular endothelial growth factor(VEGF)in HT-29 cells were determined by Western blotting analysis and their mRNA expression was determined by real-time quantitative RT-PCR. RESULTS:Treatment with 10-80μmol/L curcumin induced typical features of apoptosis and activated the caspase-3 in HT-29 cells.The expression of PPARδ, 14-3-3εand VEGF was reduced and the activity of β-catenin/Tcf-4 signaling was inhibited by curcumin treatment. CONCLUSION:Curcumin can induce apoptosis of HT-29 cells and down-regulate the expression of PPARδ,14-3-3εand VEGF in HT-29.
文摘The paper describes the expression of human protein VEGF165 in Escherichia coli and its purification. This growth factor isoform contains exon 7, which is essential for binding to extracellular domain of VEGF receptor 2, located on endothelial cells lining the surface of blood vessels. This binding stimulates the cascade of downstream signalling events leading to process known as angiogenesis, hVEGF165 overexpressed with His-tag in BL21 E. coli cells forms inclusion bodies （insoluble protein）, so the research found the procedure for its solubilization and purification on a Nickel based affinity chromatography. Although this eukaryotic signal protein needs posttranslational processing for its full function as a homodimer, author verified the biological activity of our hVEGF165 protein, obtained as monomer, by wound healing test.
文摘The tyrosine kinase receptor vascular endothelial growth factor receptor 2 （VEG FR2） is a key regulator of angiogenesis. Here we show that VEGFR2 is acetylated in endothelial cells both at four lysine residues forming a dense cluster in the kinase insert domain and at a single lysine located in the receptor activation loop. These modifications are under dynamic control of the acetyltransferase p300 and two deacetyiases HDAC5 and HDAC6. We demonstrate that VEGFR2 acetylation essentially regulates receptor phosphorylation. In par- ticular, VEGFR2 acetylation significantly alters the kinetics of receptor phosphorylation after ligand binding, allowing receptor phos- phoryiation and intraceUular signaling upon proLonged stimulation with VEGF. Molecular dynamics simulations indicate that acetylation of the lysine in the activation loop contributes to the transition to an open active state, in which tyrosine phosphorylation is favored by better exposure of the kinase target residues. These findings indicate that post-translational modification by acetyiation is a critical mechanism that directLy affects VEGFR2 function.
