Hypoxia-inducible factor 1alpha (HIF-1alpha), which transactivates a variety of hypoxia-induced genes, is rapidly degraded under nomoxia through the hydroxylation-ubiquitination-proteasome pathway. In this study, we addressed how HIF-1alpha is stabilized by proteasome inhibitors. The ubiquitin pool was rapidly reduced after proteasome inhibition, followed by the accumulation of non-ubiquitinated HIF-1alpha. The poly-ubiquitination of HIF-1alpha was resumed by restoration of free ubiquitin, which suggests that the HIF-1alpha stabilization under proteasome inhibition is attributed to depletion of the free ubiquitin pool. Ni2+ and Zn2+ also stabilized HIF-1alpha with depletion of the free ubiquitin pool and these effects of metal ions were attenuated by restoration of free ubiquitin. Ni2+ and Zn2+ may disturb the recycling of free ubiquitin, as MG132 does. Based on these results, the state of the ubiquitin pool seems to be another critical factor determining the cellular level of HIF-1alpha.
Cell Hypoxia/physiology ; Cell Line, Tumor ; HCT116 Cells ; HEK293 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis/*metabolism ; Leupeptins/pharmacology ; Nickel/chemistry ; Proteasome Endopeptidase Complex/*metabolism ; Proteasome Inhibitors/*pharmacology ; Ubiquitin/*metabolism ; Ubiquitination/*physiology ; Up-Regulation ; Zinc/chemistry

The purpose of this study was to devise an expanded ischemic flap model and to investigate the role of AMD-3100 (Plerixafor, chemokine receptor 4 inhibitor) in this model by confirming its effect on mobilization of stem cells from the bone marrow. Male Sprague-Dawley rats were used as an animal research model. The mobilization of stem cells from the bone marrow was confirmed in the AMD-3100-treated group. The fractions of endothelial progenitor cells (EPC) and the vascular endothelial growth factor receptor (VEGFR) 2+ cells in the peripheral blood were increased in groups treated with AMD-3100. The expression of vascular endothelial growth factor (VEGF) was increased in response to expansion or AMD injection. The expression of stromal cell derived factor (SDF)-1 and VEGFR2 were increased only in unexpanded flap treated with AMD-3100. Treatment with AMD-3100 increased both the number and area of blood vessels. However, there were no statistically significant differences in the survival area or physiologic microcirculation in rats from the other groups. This endogenous neovascularization induced by AMD-3100 may be a result of the increase in both the area and number of vessels, as well as paracrine augmentation of the expression of VEGF and EPCs. However, the presence of a tissue expander under the flap could block the neovascularization between the flap and the recipient regardless of AMD-3100 treatment and expansion.
Animals ; Anti-HIV Agents/pharmacology ; Bone Marrow Cells/cytology ; Chemokine CXCL12/biosynthesis ; Endothelial Progenitor Cells/*cytology ; Hematopoietic Stem Cells/*cytology ; Heterocyclic Compounds/*pharmacology ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism ; Male ; Neovascularization, Physiologic ; Nitric Oxide Synthase Type III/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, CXCR4/antagonists & inhibitors ; Surgical Flaps/*blood supply/surgery ; Tissue Expansion/*methods ; Vascular Endothelial Growth Factor A/biosynthesis ; Vascular Endothelial Growth Factor Receptor-2/biosynthesis/metabolism

In order to investigate the expression of nerve growth factor (NGF) and hypoxia inducible factor-1&alpha; (HIF-1&alpha;) and its correlation with angiogenesis in non-small cell lung cancer (NSCLC), paraffin-embedded tissue blocks from 20 patients with NSCLC were examined. Twenty corresponding para-cancerous lung tissue specimens were obtained to serve as a control. The expression of NGF, HIF-1&alpha;, and vascular endothelial growth factor (VEGF) in the NSCLC tissues was detected by using immunohistochemistry. The microvascular density (MVD) was determined by CD31 staining. The results showed that the expression levels of NGF, HIF-1&alpha; and VEGF in the NSCLC tissues were remarkably higher than those in the para-cancerous lung tissues (P<0.05). There was significant difference in the MVD between the NSCLC tissues (9.19±1.43) and para-cancerous lung tissues (2.23±1.19) (P<0.05). There were positive correlations between NGF and VEGF, between HIF-1&alpha; and VEGF, and between NGF and HIF-1&alpha; in NSCLC tissues, with the spearman correlation coefficient being 0.588, 0.519 and 0.588, respectively. In NSCLC tissues, the MVD had a positive correlation with the three factors (P<0.05). Theses results suggest that NGF and HIF-1&alpha; are synergically involved in the angiogenesis of NSCLC.
Adult ; Aged ; Carcinoma, Non-Small-Cell Lung ; blood supply ; metabolism ; Female ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; Immunohistochemistry ; Lung ; blood supply ; metabolism ; pathology ; Lung Neoplasms ; blood supply ; metabolism ; Male ; Middle Aged ; Neovascularization, Pathologic ; metabolism ; Nerve Growth Factor ; biosynthesis ; Vascular Endothelial Growth Factor A ; metabolism ; Young Adult

OBJECTIVETo observe the therapeutic angiogenesis effect of naotai recipe (NR) on local ischemia/reperfusion (I/R) injury of rats by observing signaling pathway of hypoxia-inducible factor-l&alpha; (HIF-1&alpha;) and vascular endothelial growth factor (VEGF).

METHODSTotally 120 Sprague-Dawley (SD) rats were randomly divided into 4 groups, namely, the normal control group (n =12), the sham-operation group (n =12), the I/R model group (n =48), and the NR group (n =48). Cerebral I/R injury models were established using thread suture method. Rats in the I/R model group and the NR group were sub-divided into 4 sub-groups according to the 1st, 3rd, 5th, and 7th I/R day (n =12). The phenomenon of neovasculization was observed by immunofluorescence staining. The protein and mRNA expression levels of HIF-la, VEGF-A, and VEGFR II receptor were detected by RT-PCR.

RESULTSThere were a large amount of labels for neovasculization in the ischemic area of the NR group. Double-immunofluorescence labeling [vWF (red) and BrdU (green)] was observed in the NR group. Compared with the model group, the HIF-1&alpha; protein expression was obviously enhanced on the 1 st day of I/R (P <0.01), and the VEGF protein expression started to enhance on the 3rd day in the NR group (P <0.01). The VEGFR protein expression level was the highest in the NR group on the 5th day of I/R (P <0.01). The protein expression of VEGF and HIF-1&alpha; started to decrease on the 7th day of I/R.

CONCLUSIONNR could strengthen angiogenesis after I/R by elevating the expression of HIF-l&alpha; and activating HIF-l&alpha;/VEGF signaling pathway.

Animals ; Brain Ischemia ; metabolism ; Cerebral Infarction ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Hypoxia-Ischemia, Brain ; metabolism ; Ischemia ; Neovascularization, Pathologic ; Rats, Sprague-Dawley ; Reperfusion Injury ; Signal Transduction ; Vascular Endothelial Growth Factor A ; biosynthesis

OBJECTIVETo investigate the influence of lyophilization on the biological activity of recombinant adenovirus-mediated triple mutant of hypoxia inducible factor-1&alpha; (Ad-HIF-1&alpha;-564/402/803).

METHODSAd-HIF-1&alpha;-564/402/803 was amplified from HEK293A cells and purified by ultracentrifugation in CsCl gradient solutions. The infection efficiency was observed by X-gal staining. The lyophilized adenovirus was prepared under appropriate conditions. Before and after lyophilization, the effect of Ad-HIF-1&alpha;-564/402/803 on hMVEC proliferation was evaluated by MTS assay. The recombinant adenovirus was confirmed by PCR and DNA sequence analysis before and 1 day, 6 months and 12 months after lyophilization, and hMVECs infected with Ad-HIF-1&alpha;-564/402/803 at these time points were examined for HIF-1&alpha; protein expression using Western blotting.

RESULTSNo significant changes were observed in the effect of lyophilized Ad-HIF-1&alpha;-564/402/803 on hMVECs proliferation at the optimal multiplicity of infection of 100 pfu/cell (P>0.05). At the 4 time points, the recombinant adenovirus HIF-1&alpha; showed no structural alterations or significant changes in the expression level of HIF-1&alpha; protein in the transfected hMVECs (P>0.05).

CONCLUSIONLyophilized Ad-HIF-1&alpha;-564/402/803 can maintain its biological activities for a long time.

Adenoviridae ; genetics ; metabolism ; Antibodies, Monoclonal ; genetics ; Freeze Drying ; Genetic Vectors ; HEK293 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Mutant Proteins ; genetics ; metabolism

OBJECTIVETo investigate the effect of recombinant adenovirus-mediated hypoxia-inducible factor-1alpha (Ad-HIF-1alpha) at different doses on angiogenesis in a rabbit model of hind limb ischemia.

METHODSLeft hind limb ischemia was induced in 45 Zealand white rabbits by ligation of the left femoral artery. The rabbits were randomly divided into 5 groups (n=9) to receive intramuscular injections of 0.5 ml saline, 2x10(10) PFU empty vector (Ad-null), or different doses of Ad-HIF-1alpha (2x10(9), 2x10(10) or 2x10(11) PFU) immediately after the operation. On the 7th day after the operation, real-time PCR was used to detect the expression of HIF-1alpha mRNA in the skeletal muscles. Immediately and on the 14th and 28th days after the operation, contrast enhanced ultrasound (CEU) was used to observe the blood perfusion of the hind limb. On the 28th day postoperatively, immunohistochemistry for CD31 was performed to evaluate the microvascular density (MVD).

RESULTSReal-time PCR showed that Ad-HIF-1alpha significantly increased the expression of HIF-1alpha mRNA (P<0.01) in a dose-dependent manner as compared with that in the saline and Ad-null groups (P<0.01). CEU revealed greater blood perfusion in the hind limb of rabbits in association with increased dose of Ad-HIF-1alpha (P<0.05 or P<0.01); similar changes in the MVD was observed following Ad-HIF-1alpha injections as shown by immunohistochemistry (P<0.05 or P<0.01). No significant differences were found either in the blood perfusion or MVD between saline and Ad-null groups (P>0.05).

CONCLUSIONAd-HIF-1alpha can dose-dependently promote the angiogenesis in the ischemic limb of rabbits.

Adenoviridae ; genetics ; metabolism ; Animals ; Female ; Genetic Therapy ; Hindlimb ; blood supply ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Ischemia ; drug therapy ; physiopathology ; Male ; Neovascularization, Physiologic ; drug effects ; Rabbits ; Random Allocation ; Recombinant Proteins ; administration & dosage ; biosynthesis ; genetics

OBJECTIVETo investigate the effect of recombinant adenovirus-mediated triple mutant of hypoxia inducible factor-1alpha (Ad-HIF-1alpha-564/402/803) in modulating angiogenesis in vitro.

METHODSThe recombinant adenoviruses Ad-lacZ, Ad-Null, Ad-HIF-1alpha-nature, and Ad-HIF-1alpha-564/402/803 were amplified in HEK293A cells and purified by ultracentrifugation in CsCl step gradient solutions, and the adenoviral titer was determined by end-point dilution assay. The recombinant adenovirus was confirmed by PCR and DNA sequence analysis, and the infection efficiency was observed by X-gal staining. Human microvascular endothelial cells (HMVECs) were infected with Ad- HIF-1alpha-564/402/803, Ad- HIF-1alpha-nature, or Ad-Null to compare the number of capillary-like tube structures in vitro. The effect of Ad- HIF-1alpha-564/402/803, Ad-HIF-1alpha-nature, and Ad-Null on angiogenesis was evaluated using a chick embryo chorioallantoic membrane (CAM) model.

RESULTSPCR and gene sequencing suggested the correct construction of the recombinant adenovirus HIF-1alpha, and the adenoviral titer reached 1011-1012 PFU/ml. Infection of the hMVECs with Ad-HIF-1alpha-564/402/803 at the optimal multiplicity of infection of 100 pfu/cell resulted in a significantly greater number of capillary-like tube structures than infection by Ad-HIF-1alpha-nature and Ad-Null (P=0.000). Ad-HIF-1alpha-564/402/803 group showed significantly higher microvessel density than Ad-HIF-1alpha-nature, Ad-Null, and PBS groups, with also higher angiogenesis area to CAM area ratio (P=0.01, 0.000, and 0.000, respectively).

CONCLUSIONThe triple mutant Ad-HIF-1alpha-564/402/803 can obviously promote the formation of capillary-like tube structures in vitro and modulate angiogenesis in the CAM model, suggesting the capacity of Ad-HIF-1alpha-564/402/803 in promoting angiogenesis under normoxic condition.

Adenoviridae ; genetics ; metabolism ; Animals ; Capillaries ; Chick Embryo ; Chorioallantoic Membrane ; blood supply ; Endothelial Cells ; cytology ; metabolism ; HEK293 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Mutation ; Neovascularization, Physiologic ; genetics ; Recombinant Proteins ; biosynthesis ; genetics

OBJECTIVETo investigate the mechanism by which recombinant adenovirus (Ad)-mediated mutations of hypoxia inducible factor 1alpha (Ad-HIF-1alpha-Ala564-Ala803) regulates cell apoptosis.

METHODSLoVo cells were infected with recombinant Ad-HIF-1alpha-Ala564-Ala803 and control virus Ad-lacZ under normoxia condition. Real-time PCR was used to detect HIF-1alpha and p21WAF1/CIP1 mRNA expressions at different time points. Western blotting was employed to verify HIF-1alpha and p21WAF1/CIP1 protein expression. Hoechst 33342 flourescein staining was performed to observe the ratio of apoptotic LoVo cells.

RESULTSThe expression levels of HIF-1alpha mRNA and protein increased after infection with Ad-HIF-1alpha- Ala564-Ala803, accompanied by an increase in p21WAF1/CIP1 mRNA and protein expressions. The apoptotic ratio was significantly higher in LoVo cells infected with recombinant Ad-HIF-1alpha-Ala564-Ala803 (16.2%) than in the control cells (5.5%, P=0.00).

CONCLUSIONHIF-1alpha may induce cell cycle arrest by up-regulating p21WAF1/CIP1 expressions to promote LoVo cell apoptosis.

Adenoviridae ; genetics ; Apoptosis ; genetics ; physiology ; Blotting, Western ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Mutagenesis, Site-Directed ; Mutation ; RNA, Messenger ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

In present study, we investigated the mechanism of regulating HIF-1alpha expression by hydroxysafflor yellow A (HSYA) in Eahy 926 cell line under 1% O2 hypoxia. Eahy 926 cells were incubated with HSYA (100, 10 and 1 micromol x L(-1)) under hypoxia for the indicated time after treatment. Cell proliferation rate was detected using MTT assays. VHL and p53 location and protein expression were analyzed by immunocytochemical stain. HIF-1alpha, VHL and p53 mRNA expression were detected by RT-PCR. Protein expression of HIF-1alpha, VHL and p53 were assayed by Western blotting method. HSYA at 100 micromol x L(-1) increased Eahy 926 cells proliferation rate under hypoxia. HIF-1alpha mRNA and protein expression were up-regulated in the presence of HSYA. VHL, p53 mRNA and protein expression decreased significantly after 8 hours of treatment under hypoxia. HSYA protected Eahy 926 cells from hypoxia, and up-regulated HIF-1alpha expression partially via its inhibition of VHL and p53 expression.
Carthamus tinctorius ; chemistry ; Cell Hypoxia ; Cell Line ; Cell Proliferation ; drug effects ; Chalcone ; analogs & derivatives ; isolation & purification ; pharmacology ; Endothelial Cells ; cytology ; metabolism ; Flowers ; chemistry ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Plants, Medicinal ; chemistry ; Quinones ; isolation & purification ; pharmacology ; RNA, Messenger ; metabolism ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics ; Umbilical Veins ; cytology ; Up-Regulation ; Von Hippel-Lindau Tumor Suppressor Protein ; biosynthesis ; genetics

OBJECTIVETo determine whether human prostate cancer cell lines undergo epithelial-mesenchymal transition (EMT) and become more invasive when induced by HIF-1alpha, and to explore the underlying molecular mechanism.

METHODSThe cell line LNCaP, appropriate for the HIF-1alpha induction test, was screened out from 4 different EMT-negative prostate cell lines through vimentin gene detection by RT-PCR. The recombinant plasmid pCDNA3. 1(-)/HIF-1alpha was constructed and transfected into LNCaP with the Lipofectamine 2000 system. The control plasmid pCDNA3.1 (-) was transfected by the same method. The positive clone cells were selected by G418 and confirmed by Western blot and immunofluorescence staining. Then a Transwell polycarbonate filter, coated with 100 micol Matrigel at 1:20 dilution in the serum-free medium, was used to analyze the invasive potency. The expression of E-cadherin and vimentin was detected by Western blot.

RESULTSAmong the 4 different EMT-negative cell lines, LNCaP was the only one that expressed the vimentin gene but not protein. The expression of HIF1alpha was obviously higher in LNCaP/HIF1alpha than in LNCaP/pCDNA3. 1 (- an LNCaP. The number of the LNCaP/HIF1alpha cells that penetrated through the Transwell polycarbonate filter was significantly larger than that of the LNCaP and LNCaP/pCDNA3. 1(-) cells. Compared with the LNCaP/pCDNA3.1(-) and LNCaP cells, the expression of vimentin was up-regulated, while that of E-cadherin down-regulated, in LNCaP/HIF1alpha.

CONCLUSIONThe over-expression of HIF-1alpha could induce EMT in the human prostate carcinoma cell line LNCaP and enhance its invasiveness through E-cadherin and vimentin regulation.

Cadherins ; biosynthesis ; Cell Line, Tumor ; metabolism ; pathology ; Epithelium ; pathology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Male ; Neoplasm Invasiveness ; Prostatic Neoplasms ; metabolism ; pathology ; Reverse Transcriptase Polymerase Chain Reaction ; Vimentin ; biosynthesis