PURPOSE: Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1alpha (HIF-1alpha) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1alpha-induced invasive characteristics. MATERIALS AND METHODS: Cells were cultured under controlled hypoxic environments (1% O2) or normoxic conditions. The effect of hypoxia on HIF-1alpha, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1alpha and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1alpha, tissue analysis was done. RESULTS: Hypoxia induces HIF-1alpha expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1alpha via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1alpha with RNA interference suppressed hypoxia-induced HIF-1alpha and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1alpha. These were confirmed in the orthotopic FTC model. CONCLUSION: Hypoxia induced HIF-1alpha, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.
Adenocarcinoma, Follicular/*genetics/metabolism ; Animals ; Anoxia/*genetics ; Cadherins/genetics ; Epithelial-Mesenchymal Transition/*genetics ; Gene Expression Regulation, Neoplastic ; Hypoxia-Inducible Factor 1, alpha Subunit/*genetics/metabolism ; Lymphokines ; Mice ; Neoplasm Invasiveness ; Phenotype ; Real-Time Polymerase Chain Reaction ; Signal Transduction/drug effects ; Thyroid Neoplasms/*genetics/metabolism ; Transcriptional Activation ; Twist Transcription Factor/*genetics/metabolism ; Vimentin/metabolism

OBJECTIVETo explore the in vitro methods of isolation and culture of human fetal epidermal stem cells (HFESCs) and the feasibility of the cultured cells as the target cells for gene transfection.

METHODSThe HFESCs were isolated by means of type IV collagen rapid adhering method. The culture medium for HFESCs was prepared according to that for human fetal fibroblasts. The cultured cells were identified by immunohistochemistry staining of keratin-19 and integrin-beta1, cell cycle analysis and clone forming rate determination. Then the cultured cells were gene transfected in vitro by liposome mediating method in which eukaryon expression vector pcDNA3.1/VEGF165 containing vascular endothelial growth factor 165 (VEGF165) were transfected into cultured cells, or by virus vector mediating method in which recombinant adenovirus accompanied vector (raav) containing green fluorescent protein (GFP) (raav/GFP) were transfected into the cultured cells, respectively. The results of in vitro gene transfection of HFESCs were observed by immunohistochemisty staining and fluorescence microscope.

RESULTSHFESCs grew well and formed large clones with higher cloning efficiency and higher ratio of G1 cells than keratinocytes. The cultured cells were strongly positive with immunohistochemistry staining of keratin-19 and integrin-beta1. After being gene-transfected by pcDNA3.1/VEGF165, the VEGF165 of HFESCs showed positive immunohistochemistry staining property, while the HFESCs transfected by raav/GFP exhibited strong fluorescence.

CONCLUSIONHFESCs could be isolated and cultured in vitro by means of rapid adherence to type IV collagen. It seemed feasible that HFESCs were gene transfected with liposome or adeno-associated virus as the vector.

Cell Adhesion ; Cell Cycle ; physiology ; Cells, Cultured ; Endothelial Growth Factors ; genetics ; metabolism ; Epidermis ; Fetus ; G1 Phase ; Green Fluorescent Proteins ; Humans ; Immunohistochemistry ; Integrin beta1 ; analysis ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; Keratinocytes ; cytology ; Keratins ; analysis ; Luminescent Proteins ; genetics ; metabolism ; Lymphokines ; genetics ; metabolism ; Microscopy, Fluorescence ; Plasmids ; genetics ; Stem Cells ; chemistry ; cytology ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

OBJECTIVETo explore the response of nasal mucosa epithelial cells to hypoxia in terms of formation of nasal polyps (NP).

METHODSEpithelial cells of NP and inferior turbinate (IT) were cultured serum-free under normal oxygen and hypoxic circumstances with stimulation of IL-1 beta and TNF alpha. The vascular endothelial growth factor (VEGF) mRNA and VEGF protein levels of the cultured cells were detected using in situ hybridization and ELISA, respectively.

RESULTSThe expression of VEGF mRNA was significantly higher in epithelial cells of NP than in IT exposed to pro-inflammatory cytokines or hypoxia (P < 0.01). VEGF levels were higher in NP epithelial cells than those of IT (P < 0.01) under hypoxia.

CONCLUSIONVEGF-induced by hypoxia is very important for the early stages of forming polyps.

Cell Hypoxia ; physiology ; Cells, Cultured ; Endothelial Growth Factors ; genetics ; Enzyme-Linked Immunosorbent Assay ; Erythropoietin ; genetics ; Humans ; Intercellular Signaling Peptides and Proteins ; genetics ; Interleukin-1 ; pharmacology ; Lymphokines ; genetics ; Nasal Mucosa ; metabolism ; Nasal Polyps ; etiology ; metabolism ; RNA, Messenger ; analysis ; Tumor Necrosis Factor-alpha ; pharmacology ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

By using AdEasy system, which is based on the homologous recombination in bacteria, an EGFP labled recombinant adenovirus vector containing hVEGF(165) was generated quickly and its property was studied in vitro. First, hVEGF(165) coding sequence was subcloned into the shuttle plasmid pAdTrack-CMV, then linearized and cotransferred with adenoviral backbone vector pAdEasy-1 into E. coli strain BJ(5183). After positive kanamycin-resistant colony was picked up, the recombinant adenoviral plasmid was identified by restriction analysis with PacI and transfected into HEK 293 cells to assembly replication-defective adenovirus Ad-EGFP/hVEGF(165). The further amplified recombinant adenoviruses were purified by CsCl banding at 32,000 rpm for 18 to 24 hours. Electron microscopy and PCR were performed for testing the recombinant adenovirus. The results showed that the purified particles were homogenous hexagon with a high titer up to 2 x 10(12)pfu/ml. An amplified band of 540 bp fragment demonstrated the successful insert of hVEGF(165). Under fluorescence microscopy, the expression of EGFP was easily detected in HEK 293 and other target cells. The maximal stimulating effect on the proliferation of hUVEC was obtained when the given multiplicity of infection (MOI) of Ad-EGFP/hVEGF(165) was 100. The rate of EGFP positive mouse bone marrow mononuclear cells analysed by flow cytometry was 27.3% after 24 hour-incubation with Ad-EGFP/hVEGF(165) (MOI = 100), and the expression of hVEGF(165) protein in the conditioned medium was 1385 +/- 332 pg/10(6) cells. It is concluded that the construction of adenovirus vector by homologous recombination in bacteria using AdEasy system can be quickly and easily performed, and the prepared high titer of Ad-EGFP/hVEGF(165) is an efficient helpful vector to transfer genes into target cells, all of which make the further in vivo experiments with VEGF(165) possible.
Adenoviridae ; genetics ; ultrastructure ; Animals ; Cell Division ; genetics ; Cell Line ; Cells, Cultured ; Cloning, Molecular ; methods ; Endothelial Growth Factors ; genetics ; metabolism ; Endothelium, Vascular ; cytology ; metabolism ; Genetic Vectors ; genetics ; ultrastructure ; Green Fluorescent Proteins ; Humans ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; Leukocytes, Mononuclear ; cytology ; metabolism ; Luminescent Proteins ; genetics ; metabolism ; Lymphokines ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Microscopy, Electron ; Microscopy, Fluorescence ; Recombinant Fusion Proteins ; genetics ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

To investigate the effect of vascular endothelial growth factor (VEGF) on beta1 integrin (VLA-4 and VLA-5) activation ability in K562 cells transfected with antisense VEGF121 cDNA, K562 cells were transfected with antisense (As), sense (S) and vector (V, pcDNA(3)). Flow cytometry was used to evaluate the expression rate of VLA-4 (CD49d/CD29) and VLA-5 (CD49e/CD29) and beta1 integrin activation ability in the transfected K562 cells. The results showed that the expression rates of VLA-4 and VLA-5 were more than 92% in the transfected K562 cells and there was no difference among the K562/V, K562/S and K562/As cells. However, beta1 integrin activated 9EG7 expression rate in K562/As cells was higher than that in K562/V cells [(75.6 +/- 10.5)% vs (41.2 +/- 2.1)%, P < 0.01)] after activation with beta1 integrin activator 8A2. It is concluded that function of beta1 integrin to be activated is restored in K562 cells transfected with antisense VEGF121 cDNA.
DNA ; genetics ; DNA, Antisense ; genetics ; Endothelial Growth Factors ; genetics ; metabolism ; Flow Cytometry ; Humans ; Integrin alpha4beta1 ; biosynthesis ; Integrin alpha5beta1 ; biosynthesis ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; K562 Cells ; Lymphokines ; genetics ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

Notch signal path plays important roles in the regulation of proliferation and differentiation of hematopoietic stem cells. An extracellular domain of human Delta-like-1 (hDll-1(ext)), one of Notch ligands, was cloned and expressed in CHO cells, and the effect of hDll-1(ext) on expansion of hematopoietic stem/progenitor cells was investigated in this study. Total RNA was isolated from human marrow mononuclear cells. hDll-1(ext) was amplified by RT-PCR and cloned to T vector, then the gene was sequenced and subcloned to pcDNA3.1/Myc-His(+)A expression vector. The constructed plasmid was transfected into CHO cells with lipofectin and the expression of secreted hDll-1(ext) in G418-resistant clones was assayed by Western blot. hDll-1(ext) high-expressed clone was cultured to collect supernatant. Fusion protein hDll-1(ext) was purified from the supernatant by immobilized metal affinity chromatography (IMAC). The results showed that expression of Notch-1 receptor was detected in cord blood-derived CD34(+) cells by RT-PCR. Human umbilical blood CD34(+) cells were cultured in serum-free medium containing SCF, IL-3, VEGF, and with or without purified hDll-1(ext) for 4 or 8 days. Effect of hDll-1(ext) on the expansion of progenitor cells was analyzed then by clonogenic assays. The number of CFU-Mix and HPP-CFC generated from the culture system containing hDll-1(ext) was 1.5 times of that from the control. In conclusion, the recombinant hDll-1(ext) promotes the expansion of primitive hematopoietic progenitors.
Animals ; Antigens, CD34 ; immunology ; Binding Sites ; genetics ; CHO Cells ; Cell Division ; drug effects ; physiology ; Colony-Forming Units Assay ; Cricetinae ; Endothelial Growth Factors ; pharmacology ; Fetal Blood ; cytology ; immunology ; metabolism ; Gene Expression ; Genetic Vectors ; genetics ; Glycoproteins ; genetics ; pharmacology ; physiology ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Intercellular Signaling Peptides and Proteins ; pharmacology ; Interleukin-3 ; pharmacology ; Lymphokines ; pharmacology ; Membrane Proteins ; genetics ; RNA ; genetics ; metabolism ; Receptor, Notch1 ; Receptors, Cell Surface ; Recombinant Proteins ; isolation & purification ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cell Factor ; pharmacology ; Transcription Factors ; Transfection ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

Vascular endothelial growth factor, VEGF, is essential for endothelial cell differentiation (vasculogenesis) and for the sprouting of new capillaries from preexisting vessels (angiogenesis). In addition, there is strong evidence that VEGF is a survival factor allowing the cells to survive and proliferate under conditions of extreme stress. Hypoxia is a key regulator of VEGF gene expression. Besides hypoxia, many cytokines, hormones and growth factors can up-regulate VEGF mRNA expression in various cell types. VEGF is present in the glomerulus of both the fetal and adult kidney. The VEGF produced by glomerular epithelial cell may be responsible for maintenance of the fenestrated phenotype of glomerular epithelial cells, thus facilitating the high rate of glomerular ultrafiltration. But there is little known about the role of VEGF in the tubule. VEGF is thought to be involved in many kinds of kidney diseases. Whereas VEGF has a beneficial role in the pathogenesis in some diseases, it does harmful action in others. Because VEGF is known to be associated with the pathogenesis of some diseases, such as diabetic nephropathy, renal tumor and polycystic kidney disease, the study about the role of VEGF is going to be a target for disease control. On the other hand, an attempt at enhancing the role of VEGF has to be made at diseases like several ARF models and experimental glomerulonephritis.
Animals ; Endothelial Growth Factors/genetics/*metabolism ; Gene Expression ; Human ; Intercellular Signaling Peptides and Proteins/genetics/*metabolism ; Kidney Diseases/*metabolism/physiopathology ; Kidney Glomerulus/*metabolism ; Kidney Tubules/*metabolism ; Lymphokines/genetics/*metabolism ; Protein Isoforms/genetics/metabolism ; Receptors, Vascular Endothelial Growth Factor/metabolism ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

OBJECTIVETo investigate the killing effect of herpes simplex virus thymidine kinase gene expression actuated by the promoter of the vascular endothelial growth factor gene on human hepatocellular tumor cells under hypoxic condition.

METHODSRecombinant adenoviral vectors, AdVEGF-tk and AdVEGF-GFP, were constructed with HSV-tk or GFP under the control of VEGF promoter through AdEasy system. Then GFP expression in hepatoma cell line HepG2 and normal liver cell line L02 transfected with AdVEGF-GFP were observed under fluorescence microscope, and the sensitivity to GCV of the AdVEGF-tk-transfected cells under normoxia or hypoxia condition were monitored by MTT method.

RESULTSGFP expression actuated by VEGF promoter was detected in sporadic L02 cells, but in almost all HepG2 cells after transfected with AdVEGF-GFP. With GCV at 10 micro g/ml and MOI at 100, L02 cells were insensitive to GCV under oxic condition, but more than 70% L02 cells were killed under hypoxic condition. Moreover, HepG2 cells infected with AdVEGF-tk showed the increased GCV sensitivity under hypoxia (over 80% killed) as compared with normoxia (over 60% killed) conditions.

CONCLUSIONHypoxia enhances the GCV sensitivity of human hepatocellular tumor cells infected with recombinant AdVEGF-tk under the control of VEGF promoter.

Adenoviridae ; genetics ; Carcinoma, Hepatocellular ; pathology ; Endothelial Growth Factors ; genetics ; Gene Expression ; drug effects ; Gene Transfer Techniques ; Genetic Vectors ; genetics ; Humans ; Hypoxia ; Intercellular Signaling Peptides and Proteins ; genetics ; Liver Neoplasms ; pathology ; Lymphokines ; genetics ; Oxygen ; pharmacology ; Promoter Regions, Genetic ; physiology ; Simplexvirus ; enzymology ; Thymidine Kinase ; genetics ; metabolism ; Tumor Cells, Cultured ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

OBJECTIVETo construct a retroviral vector carrying human vascular endothelial growth factor (hVEGF (121)) cDNA for evaluation of the possibility of VEGF gene therapy in ischemic bone disease.

METHODShVEGF(121) cDNA was obtained from the plasmid pCDI/VEGF(121) and cloned into retroviral plasmid pLXSN. Recombinant plasmid was transferred to the retro virus packaging cell, PT-67, by lipofectamine mediated gene transfer. Mouse bone marrow stromal cells (MSCs) were transfected by the retrovirus. The integration of the hVEGF(121) cDNA into MSC genomic DNA and expression of the VEGF gene was detected. Proliferation assays of human umbilical vein endothelial cells (HUVECs) by VEGF(121) in culture medium were performed.

RESULTSRecombinant pLXSN/VEGF(121) was correctly constructed and confirmed by restriction endonuclease analysis and DNA sequencing analysis. hVEGF(121) gene was integrated into MSC genomic DNA after transfection, and the VEGF(121) protein was expressed. Proliferation assays showed VEGF(121) in culture medium was a biologically active protein and had a mitogenic effect on HUVEC.

CONCLUSIONSRecombinant retroviral vector carrying hVEGF(121) cDNA was successfully constructed. VEGF (121) protein expressed by MSCs had mitogenic effect biologically. This provides a further foundation for VEGF gene therapy for bone ischemic disease and bone tissue engineering.

Animals ; Bone Marrow Cells ; metabolism ; Cell Division ; DNA, Complementary ; genetics ; Endothelial Growth Factors ; genetics ; Endothelium, Vascular ; cytology ; Genetic Therapy ; Humans ; Lymphokines ; genetics ; Mice ; Plasmids ; Retroviridae ; genetics ; Stromal Cells ; metabolism ; Transgenes ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors ; Virus Assembly

Until recently, vascular endothelial growth factor (VEGF) was the only growth factor proven to be specific and critical for blood vessel formation. Other long-known factors, such as the fibroblast growth factors (FGFs), platelet-derived growth factor, or transforming growth factor-beta, had profound effects in endothelial cells. But such factors were nonspecific, in that they could act on many other cells, and it seemed unlikely that these growth factors would be effective targets for treatment of endothelial cell diseases. A recently discovered endothelial cell specific growth factor, angiopoietin, has greatly contributed to our understanding of the development, physiology, and pathology of endothelial cells (Davis et al., 1996; Yancopoulos et al., 2000). The recent studies that identified and characterized the physiological and pathological roles of angiopoietin have allowed us to widen and deepen our knowledge about blood vessel formation and vascular endothelial function. Therefore, in this review, we describe the biomedical significance of these endothelial cell growth factors, the angiopoietins, in the vascular system under normal and pathological states.
Alternative Splicing ; Angiogenesis Factor/genetics/*metabolism ; Animal ; Cell Survival ; Endothelial Growth Factors/metabolism ; Endothelium, Vascular/cytology/*physiology ; Hematopoiesis/physiology ; Human ; Intercellular Signaling Peptides and Proteins/metabolism ; Lymphokines/metabolism ; Membrane Glycoproteins/genetics/*metabolism ; Neoplasm Proteins/metabolism ; Neovascularization, Pathologic ; Neovascularization, Physiologic ; Signal Transduction/physiology ; Urogenital System/physiology