Hypoxia-inducible Factor-1α Protein Expression Research Articles

Stabilization of the c-Myc Protein via the Modulation of Threonine 58 and Serine 62 Phosphorylation by the Disulfiram/Copper Complex in Oral Cancer Cells.

MYC has a short half-life that is tightly regulated through phosphorylation and proteasomal degradation. Many studies have claimed that treatment with disulfiram (DSF) with or without copper ions can cause cancer cell death in a reactive oxygen species (ROS)-dependent manner in cancer cells. Our previous study showed that the levels of c-Myc protein and the phosphorylation of threonine 58 (T58) and serine 62 (S62) increased in DSF-Cu-complex-treated oral epidermoid carcinoma Meng-1 (OECM-1) cells. These abovementioned patterns were suppressed by pretreatment with an ROS scavenger, N-acetyl cysteine. The overexpression of c-Myc failed to induce hypoxia-inducible factor 1α protein expression, which was stabilized by the DSF-Cu complex. In this study, we further examined the regulatory mechanism behind the induction of the c-Myc of the DSF-Cu complex in an OECM-1 cell compared with a Smulow–Glickman (SG) human normal gingival epithelial cell. Our data showed that the downregulation of c-Myc truncated nick and p62 and the induction of the ratio of H3P/H3 and p-ERK/ERK might not be involved in the increase in the amount of c-Myc via the DSF/copper complexes in OECM-1 cells. Combined with the inhibitors for various signaling pathways and cycloheximde treatment, the increase in the amount of c-Myc with the DSF/copper complexes might be mediated through the increase in the stabilities of c-Myc (T58) and c-Myc (S62) proteins in OECM-1 cells. In SG cells, only the c-Myc (T58) protein was stabilized by the DSF-Cu (I and II) complexes. Hence, our findings could provide novel regulatory insights into the phosphorylation-dependent stability of c-Myc in DSF/copper-complex-treated oral squamous cell carcinoma.

Estrogen Receptor-positive Ductal Carcinoma In Situ Frequently Overexpresses HER2 Protein Without Gene Amplification

Overexpression of human epidermal growth factor receptor 2 (HER2) protein is well known to be more frequent in ductal carcinoma in situ (DCIS) than in invasive ductal carcinoma (IDC). However, the reasons for this difference are poorly understood. On the basis of the high frequency of estrogen receptor-positive (ER+) and HER2-positive (HER2+) DCIS, we hypothesized that this tumor type overexpresses HER2 protein without gene amplification and retrospectively investigated the HER2/neu gene status of 71 ER(+)HER2(+) DCIS, surgically removed during the 2007 to 2017 period, employing fluorescence in situ hybridization (FISH). To compare HER2 protein expressions between in situ and invasive components of individual tumors, 86 pT1mi/1a IDC with predominantly in situ disease were also examined. Furthermore, for comparison of FISH status between in situ and coexisting invasive components, another patient cohort, 78 FISH-positive IDC cases, were employed. To elucidate biological differences among DCIS with various combinations of ER and HER2 protein expressions, we also analyzed public microarray data of mRNA. HER2 gene amplification was observed in 35% of ER(+) and HER2 protein-overexpressing specimens, significantly lower than the 94% in ER-negative (ER-) and HER2 protein-overexpressing specimens (P<0.001). HER2 protein expression was decreased in the invasive component as compared with coexisting in situ portions in 40% of individual tumors, whereas the FISH status of these 2 components was well preserved. Moreover, ER(+) and HER2 protein-overexpressing DCIS showed significantly higher hypoxia-inducible factor-1α protein expression than the ER(+) and HER2 protein-nonoverexpressing tumors (P=0.016). We revealed that ER(+) and HER2 protein-overexpressing DCIS, especially ER-high tumors, frequently overexpress HER2 protein without gene amplification. Our data may provide novel insights for understanding the biology of DCIS.

Intracavernous Injection of Human Umbilical Cord Blood Mononuclear Cells Improves Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats

IntroductionErectile dysfunction (ED) worsens in men with diabetes. Human umbilical cord blood (HUCB), because of its widespread availability and low immunogenicity, is a valuable source for stem cell-based therapies. AimTo determine the effect of intracavernous injection of HUCB mononuclear cells (MNCs) on ED in rats with diabetes induced by streptozotocin. MethodsThirty adult male Sprague-Dawley rats were equally divided into three groups: (i) control, (ii) diabetes induced by streptozotocin (35 mg/kg intravenously for 8 weeks), and (iii) diabetic rats treated with MNCs (1 × 106 cells by intracavernosal injection). The HUCB-MNCs isolated by the Ficoll-Hypaque technique were obtained from eight healthy donors and administered to diabetic rats after 4 weeks. Main Outcome MeasuresThe ratio of intracavernosal pressure to mean arterial pressure ratio; the protein expression of endothelial and neuronal markers, such as von Willebrand factor, neuronal nitric oxide synthase, hypoxia-inducible factor-1α, and vascular endothelium growth factor; and the relative area of smooth muscle to collagen using western blotting and Masson trichrome staining were determined. ResultsDiabetic rats demonstrated a significantly decreased ratio of intracavernosal pressure to mean arterial pressure (0.26 ± 0.04; P < .01) and treatment with MNCs restored erectile function in diabetic rats (0.67 ± 0.05) compared with control rats (0.56 ± 0.02). In bath studies, neurogenic relaxant and contractile responses were significantly decreased in diabetic cavernosal tissues, which were restored by treatment. The ratio of smooth muscle to collagen was partly recovered by treatment, whereas von Willebrand factor levels were not altered in any group. Neuronal nitric oxide synthase and vascular endothelium growth factor levels were decreased, which were not restored by treatment. Increased hypoxia-inducible factor-1α protein expression in the diabetic group was completely normalized in MNC-treated diabetic samples. ConclusionThese results suggest that HUCB-MNC treatment can enhance the recovery of erectile function and promote numerous activities such the contribution of the hypoxia-inducible factor-1α and von Willebrand factor pathway to the neurogenic erectile response of diabetic rats. HUCB-MNCs in the healing process could involve an adaptive regenerative response and appear to be a potential candidate for cell-based therapy in ED of men with diabetes. It is evident that HUCB could provide a realistic therapeutic modality for the treatment of diabetic ED.

Ischemia induces different levels of hypoxia inducible factor-1α protein expression in interneurons and pyramidal neurons.

IntroductionPyramidal (glutamatergic) neurons and interneurons are morphologically and functionally well defined in the central nervous system. Although it is known that glutamatergic neurons undergo immediate cell death whereas interneurons are insensitive or survive longer during cerebral ischemia, the protection mechanisms responsible for this interneuronal survival are not well understood. Hypoxia inducible factor-1 (HIF-1) plays an important role in protecting neurons from hypoxic/ischemic insults. Here, we studied the expression of HIF-1α, the regulatable subunit of HIF-1, in the different neuronal phenotypes under in vitro and in vivo ischemia.ResultsIn a primary cortical culture, HIF-1α expression was observed in neuronal somata after hypoxia (1% oxygen) in the presence of 5 or 25 mM glucose but not under normoxia (21% oxygen). Interestingly, only certain MAP2-positive neurons containing round somata (interneuron-like morphology) co-localized with HIF-1α staining. Other neurons such as pyramidal-like neurons showed no expression of HIF-1α under either normoxia or hypoxia. The HIF-1α positive neurons were GAD65/67 positive, confirming that they were interneuron-type cells. The HIF-1α expressing GAD65/67-positive neurons also possessed high levels of glutathione. We further demonstrated that ischemia induced significant HIF-1α expression in interneurons but not in pyramidal neurons in a rat model of middle cerebral artery occlusion.ConclusionThese results suggest that HIF-1α protein expression induced by ischemia is neuron-type specific and that this specificity may be related to the intracellular level of glutathione (GSH).

The Correlation of Expression Levels of HIF-1 and HIF-2 in Hepatocellular Carcinoma with Capsular Invasion, Portal Vein Tumor Thrombi and Patients' Clinical Outcome

The roles of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α in the development of hepatocellular carcinoma have not been fully elucidated. Here, we aim to uncover the relationship between the prognosis of hepatocellular carcinoma patients and the expression of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α in tumor tissues. The protein levels of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α were detected by immunohistochemistry on paraffin sections of 126 paired hepatocellular carcinoma tissue and peritumoral tissue samples. The mRNA levels of them were detected by quantitative real-time polymerase chain reaction. High expression of hypoxia-inducible factor-1α was found in 57.1% (72/126) of tumor specimens, compared with 5.6% (7/126) in peritumoral tissues, while high expression of hypoxia-inducible factor-2α was found in only 13.5% (17/126) of tumors, compared with 47.6% (60/126) of peritumoral tissues. There was high expression of hypoxia-inducible factor-1α protein in hepatocellular carcinoma tissues closely associated with capsular infiltration and portal vein invasion, and thus lower overall survival and disease-free survival of hepatocellular carcinoma patients (P < 0.05). No significant association has been found between the expression of hypoxia-inducible factor-2α protein and capsular infiltration, portal vein invasion, overall survival and disease-free survival (P > 0.05). However, patients with high expression of both hypoxia-inducible factor-1α and hypoxia-inducible factor-2α have a significantly worse outcome than patients with low expression of both hypoxia-inducible factor-1α and hypoxia-inducible factor-2α (P < 0.05). The discordant results on expression of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α suggest that these two proteins are differentially regulated in vivo, thus reflecting distinctive protein expression and stabilization mechanisms. The association between hypoxia-inducible factor-1α expression and unfavorable outcome indicates the importance of using hypoxia-inducible factor-1α as a treatment target in hepatocellular carcinoma.

The CXCR4-CXCL12 axis in Ewing sarcoma: promotion of tumor growth rather than metastatic disease

BackgroundChemokine receptor CXCR4, together with its ligand CXCL12, plays critical roles in cancer progression, including growth, metastasis and angiogenesis. Ewing sarcoma is a sarcoma with poor prognosis despite current therapies, particularly for patients with advanced-stage disease. Lungs and bone (marrow), organs of predilection for (primary/metastatic) Ewing sarcoma, represent predominant CXCL12 sources.MethodsTo gain insight into the role of the CXCR4-CXCL12 axis in Ewing sarcoma, CXCR4, CXCL12 and hypoxia-inducible factor-1α protein expression was studied in therapy-naïve and metastatic tumors by immunohistochemistry. CXCR4 function was assessed in vitro, by flow cytometry and proliferation/ cell viability assays, in the presence of recombinant CXCL12 and/or CXCR4-antagonist AMD3100 or under hypoxic conditions.ResultsWhereas CXCR4 was predominantly expressed by tumor cells, CXCL12 was observed in both tumor and stromal areas. Survival analysis revealed an (expression level-dependent) negative impact of CXCR4 expression (p < 0.04). A role for the CXCR4-CXCL12 axis in Ewing sarcoma growth was suggested by our observations that i) CXCR4 expression correlated positively with tumor volume at diagnosis (p = 0.013), ii) CXCL12 was present within the microenvironment of virtually all cases, iii) CXCL12 induced proliferation of CXCR4-positive Ewing sarcoma cell lines, which could be abrogated by AMD3100. CXCR4 expression was not correlated with occurrence of metastatic disease. Also, therapy-naïve tumors demonstrated higher CXCR4 expression as compared to metastases (p = 0.027). Evaluation of in vivo hypoxia-inducible factor-1α expression and culture of cells under hypoxic conditions revealed no role for hypoxia in CXCR4 expression.ConclusionsTogether, our results imply a crucial role for the CXCR4-CXCL12 axis in auto- and/or paracrine growth stimulation. Integration of CXCR4-targeting strategies into first- and/or second-line treatment regimens may represent a promising treatment option for Ewing sarcoma.

Neuroprotective Effect of Acute Ethanol Administration in a Rat With Transient Cerebral Ischemia

Ethanol consumption is inversely associated with the risk of ischemic stroke, suggesting a neuroprotective effect. In a rat model of transient cerebral ischemia, we identified ethanol as a possible treatment for acute ischemic stroke. Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 2 hours. Five sets of experiments were conducted: to determine the dose-response effect of ethanol on brain infarction and functional outcome; to determine whether combining ethanol and hypothermia produces synergistic neuroprotection; to determine the therapeutic windows of opportunity for ethanol in stroke; to test whether ethanol promotes intracerebral hemorrhage in a hemorrhagic or ischemic stroke or after administration of thrombolytics; and to test the affect of ethanol on hypoxia-inducible factor-1α protein expression. Ethanol at 1.5 g/kg reduced infarct volume and behavioral dysfunction when administered at 2, 3, or 4 hours after middle cerebral artery occlusion. The protective effect of ethanol was not improved when paired with hypothermia. Ethanol did not promote cerebral hemorrhage in hemorrhagic or ischemic stroke in combination with recombinant tissue-type plasminogen activator or urokinase. Ethanol treatment (1.5 g/kg) increased protein levels of hypoxia-inducible factor-1α at 3 hours postreperfusion. Ethanol exerts a strong neuroprotective effect when administered up to 4 hours after ischemia, increases expression of hypoxia-inducible factor-1α, and does not promote intracerebral hemorrhage when used with thrombolytics. Ethanol is a potential neuroprotectant for acute ischemic stroke.

Hypoxia-inducible factor-1α protein expression is associated with poor survival in normal karyotype adult acute myeloid leukemia

We examined the predictive impact of HIF-1α protein expression on clinical outcome of 84 normal karyotype acute myeloid leukemia (NK-AML) patients (median age 66.5 years) at our institute. Thirty percent of NK-AML cells expressed cytoplasmic HIF-1α. In univariate analysis, low HIF-1α (≤5%, n = 66) was associated with improved event-free survival ( p = 0.0453, HR = 0.22). Multivariate analysis incorporating age, complete remission, FLT3-ITD mutation, and marrow blast percentage demonstrated that HIF-1α was independently associated with poorer overall and event-free survival. HIF-1α expression correlated with VEGF-C but not VEGF-A, marrow angiogenesis, FLT3 ITD or NPM1 mutations. These results support HIF-1α as an outcome marker for NK-AML.

αB-crystallin regulation of angiogenesis by modulation of VEGF

AbstractαB-crystallin is a chaperone belonging to the small heat shock protein family. Herein we show attenuation of intraocular angiogenesis in αB-crystallin knockout (αB-crystallin−/−) mice in 2 models of intraocular disease: oxygen-induced retinopathy and laser-induced choroidal neovascularization. Vascular endothelial growth factor A (VEGF-A) mRNA and hypoxia inducible factor-1α protein expression were induced during retinal angiogenesis, but VEGF-A protein expression remained low in αB-crystallin−/− retina versus wild-type mice, whereas VEGF-R2 expression was not affected. Both αB-crystallin and its phosphorylated serine59 formwere expressed, and immunoprecipitation revealed αB-crystallin binding to VEGF-A but not transforming growth factor-β in cultured retinal pigment epithelial (RPE) cells. αB-crystallin and VEGF-A are colocalized in the endoplasmic reticulum in RPE cells under chemical hypoxia. αB-crystallin−/− RPE showed low VEGF-A secretion under serum-starved conditions compared with wild-type cells. VEGF-A is polyubiquitinated in control and αB-crystallin siRNA treated RPE; however, mono-tetra ubiquitinated VEGF-A increases with αB-crystallin knockdown. Endothelial cell apoptosis in newly formed vessels was greater in αB-crystallin−/− than wild-type mice. Proteasomal inhibition in αB-crystallin−/− mice partially restores VEGF-A secretion and angiogenic phenotype in choroidal neovascularization. Our studies indicate an important role for αB-crystallin as a chaperone for VEGF-A in angiogenesis and its potential as a therapeutic target.

The role of transferrin receptor 1 and 2 in transferrin-bound iron uptake in human hepatoma cells

Transferrin receptor (TFR) 1 and 2 are expressed in the liver; TFR1 levels are regulated by cellular iron levels while TFR2 levels are regulated by transferrin saturation. The aims of this study were to 1) determine the relative importance of TFR1 and TFR2 in transferrin-bound iron (TBI) uptake by HuH7 human hepatoma cells and 2) characterize the role of metal-transferrin complexes in the regulation of these receptors. TFR expression was altered by 1) incubation with metal-transferrin (Tf) complexes, 2) TFR1 and TFR2 small interfering RNA knockdown, and 3) transfection with a human TFR2 plasmid. TBI uptake was measured using (59)Fe-(125)I-labeled Tf and mRNA and protein expression by real-time PCR and Western blot analysis, respectively. Fe(2)Tf, Co(2)Tf, and Mn(2)Tf increased TFR2 protein expression, indicating that the upregulation was not specifically regulated by iron-transferrin but also other metal-transferrins. In addition, Co(2)Tf and Mn(2)Tf upregulated TFR1, reduced ferritin, and increased hypoxia-inducible factor-1alpha protein expression, suggesting that TFR1 upregulation was due to a combination of iron deficiency and chemical hypoxia. TBI uptake correlated with changes in TFR1 but not TFR2 expression. TFR1 knockdown reduced iron uptake by 80% while TFR2 knockdown did not affect uptake. At 5 microM transferrin, iron uptake was not affected by combined TFR1 and TFR2 knockdown. Transfection with a hTFR2 plasmid increased TFR2 protein expression, causing a 15-20% increase in iron uptake and ferritin levels. This shows for the first time that TFR-mediated TBI uptake is mediated primarily via TFR1 but not TFR2 and that a high-capacity TFR-independent pathway exists in hepatoma cells.

Cyclooxygenase-2 and Hypoxia-Inducible Factor-1α protein expression is related to inflammation, and up-regulated since the early steps of colorectal carcinogenesis

Chronic mucosal inflammation is considered a risk factor for colorectal cancer. Neutrophils are a major source of oxidants, whereas cyclooxygenase 2 (COX-2) and Hypoxia Inducible Factor-1α (HIF-1α) protein expression levels are increased in inflammatory and malignant lesions. The main purpose of the present study was to evaluate myeloperoxidase (MPO) positive cell infiltration, COX-2 and HIF-1α protein expression in colorectal carcinogenesis, especially in its early phases, using immunohistochemistry and immunofluorescence confocal microscopy techniques. MPO, COX-2 and HIF-1α proteins were expressed at higher rates in the normal colorectal mucosa of patients with inflammatory bowel diseases and colorectal tumours than in patients with normal colonoscopy. A gradual increase in COX-2 and HIF-1α protein expression was observed in dysplastic aberrant crypt foci, adenomas and carcinomas, showing a strong relation to dysplasia. In conclusion, the present study supports the hypothesis of a key role of inflammation in malignant transformation of colorectal mucosa. The evaluation of some early markers related to inflammation in the mucosa of the large bowel may serve as potential tool for prognosis and therapeutic strategies.

Chronic disease management for patients with respiratory disease: Nurs Times 2005;101(25):46–8

Erectile dysfunction (ED) worsens in men with diabetes. Human umbilical cord blood (HUCB), because of its widespread availability and low immunogenicity, is a valuable source for stem cell-based therapies.To determine the effect of intracavernous injection of HUCB mononuclear cells (MNCs) on ED in rats with diabetes induced by streptozotocin.Thirty adult male Sprague-Dawley rats were equally divided into three groups: (i) control, (ii) diabetes induced by streptozotocin (35 mg/kg intravenously for 8 weeks), and (iii) diabetic rats treated with MNCs (1 × 106 cells by intracavernosal injection). The HUCB-MNCs isolated by the Ficoll-Hypaque technique were obtained from eight healthy donors and administered to diabetic rats after 4 weeks.The ratio of intracavernosal pressure to mean arterial pressure ratio; the protein expression of endothelial and neuronal markers, such as von Willebrand factor, neuronal nitric oxide synthase, hypoxia-inducible factor-1α, and vascular endothelium growth factor; and the relative area of smooth muscle to collagen using western blotting and Masson trichrome staining were determined.Diabetic rats demonstrated a significantly decreased ratio of intracavernosal pressure to mean arterial pressure (0.26 ± 0.04; P < .01) and treatment with MNCs restored erectile function in diabetic rats (0.67 ± 0.05) compared with control rats (0.56 ± 0.02). In bath studies, neurogenic relaxant and contractile responses were significantly decreased in diabetic cavernosal tissues, which were restored by treatment. The ratio of smooth muscle to collagen was partly recovered by treatment, whereas von Willebrand factor levels were not altered in any group. Neuronal nitric oxide synthase and vascular endothelium growth factor levels were decreased, which were not restored by treatment. Increased hypoxia-inducible factor-1α protein expression in the diabetic group was completely normalized in MNC-treated diabetic samples.These results suggest that HUCB-MNC treatment can enhance the recovery of erectile function and promote numerous activities such the contribution of the hypoxia-inducible factor-1α and von Willebrand factor pathway to the neurogenic erectile response of diabetic rats. HUCB-MNCs in the healing process could involve an adaptive regenerative response and appear to be a potential candidate for cell-based therapy in ED of men with diabetes. It is evident that HUCB could provide a realistic therapeutic modality for the treatment of diabetic ED.

Expression of Hypoxia-Inducible Factor-1α Protein Predicts Survival in Patients with Transitional Cell Carcinoma of the Upper Urinary Tract

Hypoxia-inducible factor-1 (HIF-1), identified as one of the transcription factors, has been found to play an essential role in oxygen homeostasis. HIF-1 is a heterodimer composed of HIF-1alpha and HIF-1beta. Increased levels of HIF-1alpha have been reported during the carcinogenesis and progress of several tumors. We investigated the prognostic importance of HIF-1alpha expression in transitional cell carcinoma of the upper urinary tract. In 127 cases of transitional cell carcinoma of the upper urinary tract, we examined its expression (using immunohistochemistry and in situ hybridization), and also its relation to the expression of p53 oncoprotein, as well as to proliferating cell nuclear antigen (PCNA) immunoreactivity, microvessel density, clinicopathologic parameters, and clinical outcome. A positive expression of HIF-1alpha protein was recognized in 55.1% of samples, the expression being apparent within the nucleus in tumor cells. HIF-1alpha protein expression correlated with grade, growth pattern, p53 oncoprotein expression, and PCNA index, but not with stage. Furthermore, a significant correlation was found between HIF-1alpha protein expression and both overall and disease-free survival rates in the univariate and multivariate analyses (in all tumors and in invasive tumors). A positive expression of HIF-1alpha mRNA was recognized in 69.6% of 125 samples which were available, the expression being apparent within the cytoplasm in tumor cells. The positive expression of HIF-1alpha mRNA by in situ hybridization correlated significantly with HIF-1alpha protein expression by immunohistochemistry. HIF-1alpha mRNA expression only correlated with pattern of growth (P = 0.0078). In conclusion, the detection of HIF-1alpha protein would seem to be of value in informing the prognosis of transitional cell carcinoma of the upper urinary tract.