Hypoxia-inducible Factor-1α Protein Research Articles

A lineage-tracing tool to map the fate of hypoxic tumour cells.

ABSTRACTIntratumoural hypoxia is a common characteristic of malignant treatment-resistant cancers. However, hypoxia-modification strategies for the clinic remain elusive. To date, little is known on the behaviour of individual hypoxic tumour cells in their microenvironment. To explore this issue in a spatial and temporally controlled manner, we developed a genetically encoded sensor by fusing the O2-labile hypoxia-inducible factor 1α (HIF-1α) protein to eGFP and a tamoxifen-regulated Cre recombinase. Under normoxic conditions, HIF-1α is degraded but, under hypoxia, the HIF-1α-GFP-Cre-ERT2 fusion protein is stabilised and in the presence of tamoxifen activates a tdTomato reporter gene that is constitutively expressed in hypoxic progeny. We visualise the random distribution of hypoxic tumour cells from hypoxic or necrotic regions and vascularised areas using immunofluorescence and intravital microscopy. Once tdTomato expression is induced, it is stable for at least 4 weeks. Using this system, we could show in vivo that the post-hypoxic cells were more proliferative than non-labelled cells. Our results demonstrate that single-cell lineage tracing of hypoxic tumour cells can allow visualisation of their behaviour in living tumours using intravital microscopy. This tool should prove valuable for the study of dissemination and treatment response of post-hypoxic tumour cells in vivo at single-cell resolution.This article has an associated First Person interview with the joint first authors of the paper.

The epigallocatechin gallate derivative Y6 reduces the cardiotoxicity and enhances the efficacy of daunorubicin against human hepatocellular carcinoma by inhibiting carbonyl reductase 1 expression

Ethnopharmacological relevanceGreen tea is the most ancient and popular beverage worldwide and its main constituent epigallocatechin-3-gallate (EGCG) has a potential role in the management of cancer through the modulation of cell signaling pathways. However, EGCG is frangible to oxidation and exhibits low lipid solubility and bioavailability, and we synthesized a derivative of EGCG in an attempt to overcome these limitations. Aim of the studyThe anthracycline antibiotic daunorubicin (DNR) is a potent anticancer agent. However, its severe cardiotoxic limits its clinical efficacy. Human carbonyl reductase 1 (CBR1) is one of the most effective human reductases for producing hydroxyl metabolites and thus may be involved in increasing the cardiotoxicity and decreasing the antineoplastic effect of anthracycline antibiotics. Accordingly, in this study, we investigated the co-therapeutic effect of Y6, a novel and potent adjuvant obtained by optimization of the structure of EGCG. Material and methodsThe cellular concentrations of DNR and its metabolite DNRol were measured by HPLC to determine the effects of EGCG and Y6 on the inhibition of DNRol formation. The cytotoxic effects of EGCG and Y6 were tested by MTT assay in order to identify non-toxic concentrations of them. To understand their antitumor and cardioprotective mechanisms, hypoxia-inducible factor-1α (HIF-1α) and CBR1 protein expression was measured via Western blotting and immunohistochemical staining while gene expression was analyzed using RT-PCR. Moreover, PI3K/AKT and MEK/ERK signaling pathways were analyzed via Western blotting. HepG2 xenograft model was used to detect the effects of EGCG and Y6 on the antitumor activity and cardiotoxicity of DNR in vivo. Finally, to obtain further insight into the interactions of Y6 and EGCG with HIF-1α and CBR1, we performed a molecular modeling. ResultsY6(10 μg/ml or 55 mg/kg) decreased the expression of HIF-1α and CBR1 at both the mRNA and protein levels during combined drug therapy in vitro as well as in vivo, thereby inhibiting formation of the metabolite DNRol from DNR, with the mechanisms being related to PI3K/AKT and MEK/ERK signaling inhibition. In a human carcinoma xenograft model established with subcutaneous HepG2 cells, Y6(55 mg/kg) enhanced the antitumor effect and reduced the cardiotoxicity of DNR more effectively than EGCG(40 mg/kg). ConclusionsY6 has the ability to inhibit CBR1 expression through the coordinate inhibition of PI3K/AKT and MEK/ERK signaling, then synergistically enhances the antitumor effect and reduces the cardiotoxicity of DNR.

Activin-A limits Th17 pathogenicity and autoimmune neuroinflammation via CD39 and CD73 ectonucleotidases and Hif1-α–dependent pathways

In multiple sclerosis (MS), Th17 cells are critical drivers of autoimmune central nervous system (CNS) inflammation and demyelination. Th17 cells exhibit functional heterogeneity fostering both pathogenic and nonpathogenic, tissue-protective functions. Still, the factors that control Th17 pathogenicity remain incompletely defined. Here, using experimental autoimmune encephalomyelitis, an established mouse MS model, we report that therapeutic administration of activin-A ameliorates disease severity and alleviates CNS immunopathology and demyelination, associated with decreased activation of Th17 cells. In fact, activin-A signaling through activin-like kinase-4 receptor represses pathogenic transcriptional programs in Th17-polarized cells, while it enhances antiinflammatory gene modules. Whole-genome profiling and in vivo functional studies revealed that activation of the ATP-depleting CD39 and CD73 ectonucleotidases is essential for activin-A-induced suppression of the pathogenic signature and the encephalitogenic functions of Th17 cells. Mechanistically, the aryl hydrocarbon receptor, along with STAT3 and c-Maf, are recruited to promoter elements on Entpd1 and Nt5e (encoding CD39 and CD73, respectively) and other antiinflammatory genes, and control their expression in Th17 cells in response to activin-A. Notably, we show that activin-A negatively regulates the metabolic sensor, hypoxia-inducible factor-1α, and key inflammatory proteins linked to pathogenic Th17 cell states. Of translational relevance, we demonstrate that activin-A is induced in the CNS of individuals with MS and restrains human Th17 cell responses. These findings uncover activin-A as a critical controller of Th17 cell pathogenicity that can be targeted for the suppression of autoimmune CNS inflammation.

Paeonol protects against testicular ischaemia-reperfusion injury in rats through inhibition of oxidative stress and inflammation.

Ischaemia-reperfusion (IR) is the most common form of testicular injury that results in oxidative damage and inflammation ending by subinfertility. Paeonol, a natural phenolic compound, exhibits antioxidant and anti-inflammatory effects. Thus, the present study investigated the role of paeonol in rat testicular IR injury. Thirty adult Wistar rats were randomly divided into five groups; sham, sham treated with paeonol, IR injury, and IR pre-treated with paeonol at low and high doses. Serum testosterone and testicular levels of malondialdehyde and reduced glutathione (GSH) besides superoxide dismutase (SOD) activity were determined. Gene quantifications for tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α) and heat shock protein 70 (HSP70) were also assessed. Histopathological pictures and the immunohistochemical expression of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were shown. Pre-treatment with paeonol prevented the drop in serum testosterone, alongside with improvement of testicular malondialdehyde and GSH levels plus SOD activity. Paeonol regained the normal spermatogenesis with prevention of IR-induced increase in TNF-α, HIF-1α and HSP70 gene expression besides IL-1β and IL-6 immunostaining and reduction in Nrf2 protein expression. Paeonol exerted a dose-dependent beneficial effect on testicular IR injury. This effect was achieved by its antioxidant and anti-inflammatory effects.

Curcumol inhibits the expression of programmed cell death-ligand 1 through crosstalk between hypoxia-inducible factor-1α and STAT3 (T705) signaling pathways in hepatic cancer

Ethnopharmacological relevanceCurcuma wenyujin is a Chinese traditional herbal medicine that is commonly used as an anti-oxidant, anti-proliferative, and anti-tumorigenic agent. Curcumol is a representative index component for the quality control of the essential oil of Curcuma wenyujin, which is currently used as an anti-cancer drug, and is included in the State Pharmacopoeia Commission of the People's Republic of China (2005). However, the mechanisms of action and molecular functions of curcumol are not yet fully elucidated. Aim of the studyThis study aimed to identify new effects of curcumol from the perspective of cancer immunotherapy. Materials and methodsThe underlying mechanism of the inhibition of programmed cell death-ligand 1 (PD-L1) activation by curcumol was investigated in vitro via homology modeling, molecular docking experiments, luciferase reporter assays, MTT assays, RT-PCR, western blotting, and immunofluorescence assays. Changes in cellular proliferation, angiogenesis, and the tumor-killing activity of T-cells were analyzed via EdU labeling, colony formation, flow cytometry, wound-healing, Matrigel Transwell invasion, tube formation, and T-cell killing. The anti-tumor activity of curcumol was assessed in vivo in a murine xenograft model using Hep3B cells. ResultsCurcumol reduced the expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) via JAK1, JAK2, and Src pathways and inhibited hypoxia-inducible factor-1α (HIF-1α) protein synthesis via mTOR/p70S6K/eIF4E and MAPK pathways. Furthermore, we revealed crosstalk between STAT3 and HIF-1α pathways, which collaboratively regulated PD-L1 activation, and that curcumol played a role in this regulation. Curcumol inhibited cell proliferation, S-phase progression, tube formation, invasion, and metastasis by inhibiting PD-L1. In addition, curcumol restored the activity of cytotoxic T-cells and their capacity for tumor cell killing by inhibiting PD-L1. In vivo experiments confirmed that curcumol inhibited tumor growth in a xenograft model. ConclusionsThese results illustrated that curcumol inhibits the expression of PD-L1 through crosstalk between HIF-1α and p-STAT3 (T705) signaling pathways in hepatic cancer. Thus, curcumol might represent a promising lead compound for the development of new targeted anti-cancer therapeutics.

Isolinderalactone suppresses human glioblastoma growth and angiogenic activity in 3D microfluidic chip and in vivo mouse models.

Glioblastoma multiforme (GBM) is a lethal and highly vascular type of brain tumor. We previously reported that isolinderalactone enhances GBM apoptosis in vitro and in vivo, but its role in tumor angiogenesis is unknown. Here, we investigated the anti-angiogenic activity of isolinderalactone and its mechanisms. In a human GBM xenograft mouse model, isolinderalactone significantly reduced tumor growth and vessels. Isolinderalactone decreased the expression of vascular endothelial growth factor (VEGF) mRNA, protein, and VEGF secretion in hypoxic U-87 GBM cells and also in xenograft GMB tissue. In addition, we demonstrated that isolinderalactone significantly inhibited the proliferation, migration, and capillary-like tube formation of human brain microvascular endothelial cells (HBMECs) in the presence of VEGF. We also found that isolinderalactone decreased sprout diameter and length in a 3D microfluidic chip, and strongly reduced VEGF-triggered angiogenesis in vivo Matrigel plug assay. Isolinderalactone downregulated hypoxia-inducible factor-1α (HIF-1α) and HIF-2α proteins, decreased luciferase activity driven by the VEGF promoter in U-87cells under hypoxic conditions, and suppressed VEGF-driven phosphorylation of VEGFR2 in HBMECs. Taken together, our results suggest that isolinderalactone is a promising candidate for GBM treatment through tumor angiogenesis inhibition.

Antioxidative effect and mechanism of tert-butyl hydroquinone on rat retinal Müller cells under high glucose condition

Objective To expore the impact of teniary butyl hydroquinone (tBHQ) on Muller cells in SD rats retina under high glucose condition, and discuss the mechanism of tBHQ. Methods The Muller cells of SD rats were cultured in vitro and the experiment was divided into normal control group, high glucose group and tBHQ intervention group.Western blot and quantitative real time PCR were used to determine the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) protein and mRNA in each group. Results Muller cells cultured in vitro were flat with irregularly sharp.The nucleus was oval, while the cytoplasm was abundant.Adjacent cells were interwoven to a network.Western blot assay showed the overall expression of Nrf2, HO-1, HIF-1α, and VEGF in Muller cells of normal control group, high glucose group, and tBHQ intervention group were significantly different (F=73.831, 148.618, 152.269, 91.217, all at P<0.001); Among them, the relative expressions of Nrf2, HO-1, HIF-1α and VEGF proteins in the high glucose group were 0.17±0.02, 0.47±0.02, 0.67±0.07, and 0.6±0.05, which were increased in comparion with 0.06±0.01, 0.19±0.03, 0.06±0.00 and 0.07±0.02 in the normal control group, with statistically significant differences (t=4.114, 9.275, 16.479, 13.353, all at P<0.001); the relative expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 0.40±0.06 and 0.72±0.05, which were increased by comparion with those in the higher glucose group, with statistically significant differences (t=7.847, 7.947, both at P<0.001); the relative expressions of HIF-1α and VEGF proteins in the tBHQ intervention group were 0.18±0.04, 0.26±0.07, which were decreased in comparion with those in the higher glucose group, but were increased in comparion with those in normal control group, with statistically significant differences (t=13.215, 8.444, both at P<0.001). Quantitative real time PCR showed that the relative mRNA expressions of Nrf2, HO-1, HIF-1α, and VEGF in Muller cells of normal control group, high glucose group, and tBHQ intervention group were significantly different (F=340.317, 1 582.911, 488.852, 185.699, all at P<0.001); the relative mRNA expressions of Nrf2, HO-1, HIF-1α, and VEGF proteins in the high-glucose group were 1.53±0.06, 1.50±0.04, 2.56±0.09, and 3.04±0.19, which were increased in comparion with 1.07±0.07, 0.95±0.05, 0.99±0.02, and 1.09±0.08 in the normal control group, with statistically significant differences (t=7.292, 15.014, 30.550, 18.573, all at P<0.001); The relative mRNA expressions of Nrf2 and HO-1 proteins in the tBHQ intervention group were 2.68±0.09 and 2.94±0.05, which were increased in comparion with those in the high-glucose group, with statistically significant differences (t=18.046, 39.458, both at P<0.001); The relative mRNA expression of HIF-1α and VEGF protein in the tBHQ intervention group were 1.48±0.05 and 1.6±0.08, which were decreased by comparion with those in the higher glucose group were increased in comparion with those in normal control group, with statistically significant differences (t=21.036, 13.739, both at P<0.001). Conclusions tBHQ protects Muller cells from damage in high glucose condition by activating anti-oxidative stress signaling pathway of Nrf2/ARE. Key words: Diabetic retinopathy; Muller cells; Teniary butyl hydroquinone; Oxidative stress; Protective mechanism

20(R)-ginsenoside Rg3, a product of high-efficiency thermal deglycosylation of ginsenoside Rd, exerts protective effects against scrotal heat-induced spermatogenic damage in mice

Heat stress (HS) reaction can lead to serious physiological dysfunction associated with cardiovascular and various organ diseases. Ginsenoside Rg3 (G-Rg3) is a representative component of ginseng rare saponin and can protect against multiple organs, also used as functional food to adjust the balance of the human body, but the therapeutic effect and molecular mechanism of G-Rg3 on male diseases under HS are underexplored. The aim of the present study, G-Rg3 was prepared through the efficient conversion of ginsenoside Rd and investigate the contribution of G-Rg3 to testicular injury induced exposure to HS. All mice were divided into four groups as follows: normal group, HS group, and HS+G-Rg3 (5 and 10 mg/kg) groups. G-Rg3 was administered orally for 14 days, then exposed to a single scrotal heat treatment (43°C, 18min) on the 7th day. After HS treatment, the morphology of testis and epididymis changes, and caused a significant loss of multinucleated giant cells, desquamation of germ cells in destructive seminiferous tubules, and degenerative Leydig cells, further destroying the production of sperm. After administration G-Rg3 (5 and 10 mg/kg/day) for 2 weeks, the spermatogenic-related indexes of testosterone levels and superoxide dismutase (SOD) activity, glutathione (GSH) content significantly (p < 0.01) increase compared with the HS group. Moreover, G-Rg3 treatment effectively ameliorated the production of malondialdehyde (MDA) (p < 0.05 or p < 0.01). Importantly, G-Rg3 exhibited the protective potential against HS-induced injury not only suppressing the protein levels of heme oxygenase-1 (HO-1), hypoxia-inducible factor-1α (HIF-1α), and heat shock protein 70 (HSP70) but also modulating the Bcl-2 family (p < 0.01 or p < 0.001) and activation of mitogen-activated protein kinase (MAPK) signaling pathways (p < 0.01). For most of the parameters tested, the HS+G-Rg3 (10 mg/kg) group exhibited potent effects compared with those exhibited by the low dose (5 mg/kg) group. In conclusion, the present study demonstrated that G-Rg3 exerted protective effects against HS-induced testicular dysfunction via inhibiting the MAPK-mediated oxidative stress and apoptosis in mice.

The role of monoamine oxidase A in HPV-16 E7-induced epithelial-mesenchymal transition and HIF-1α protein accumulation in non-small cell lung cancer cells.

Our previous studies have found that human papillomavirus (HPV)-16 E7 oncoprotein promotes epithelial-mesenchymal transition (EMT) and hypoxia-inducible factor-1α (HIF-1α) protein accumulation in non-small cell lung cancer (NSCLC) cells and monoamine oxidase A (MAOA) is highly expressed in NSCLC tissues. Here, we further explored the role of MAOA in HPV-16 E7-induced EMT and HIF-1α protein accumulation in A549 and NCI-H460 NSCLC cells. Our results showed that HPV-16 E7 enhanced MAOA expression in NSCLC cells. Additionally, MAOA knockout inhibited HPV-16 E7-induced migration, invasion, and EMT, and significantly reduced HPV-16 E7-induced ROS generation and HIF-1α protein accumulation via promoting its degradation. Furthermore, MAOA knockout suppressed HPV-16 E7-induced ERK1/2 activation. In vivo, MAOA knockout inhibited tumor growth, metastasis, and the expression of EMT-related markers and HIF-1α proteins induced by HPV-16 E7 in NCI-H460 NSCLC subcutaneous xenograft and in situ intrapulmonary models of nude mice. Taken together, our findings provide evidence that MAOA plays a key role in EMT and HIF-1α protein accumulation induced by HPV-16 E7 in NSCLC cells, suggesting that MAOA may be a potential therapeutic target for HPV-related NSCLC.

Inhibitory effect of exosomes secreted by human umbilical cord mesenchymal stem cells on apoptosis of oxygen-glucose deprived reoxygenation model of venous endothelial cells

Objective To explore the inhibitory effect of exosomes secreted by human umbilical cord mesenchymal stem cells(HUCMSC) on apoptosis of human umbilical vein endothelial cells(HUVEC) after model group(oxygen-glucose deprivation reoxygenation), and to clarify its possible mechanism. Methods Human umbilical cord mesenchymal stem cells were cultured. The collected cell supernatant was stored in a centrifugal tube. The exosomes secreted by human umbilical cord mesenchymal stem cells were extracted by ultracentrifugation and identified. Human umbilical vein endothelial cells were randomly divided into control group, model group and different concentrations of HUCMSC-EXO(20 μg/ml, 40 μg/ml, 60 μg/ml) treatment groups(adding HUCMSC-EXO into the model group) . The morphological changes of HUVEC cells in each group were observed by inverted phase contrast microscope, and the proliferation inhibition rate of HUVEC in each group was measured by CCK-8 reagent. Western blot was used to detect the expression of apoptosis-related proteins Caspase-3, Bax, Bcl-2 and hypoxia-associated protein hypoxia inducible factor 1α(HIF-1α). Inhibitor(HIF-1α inhibitor) + model group and HUCMSC-EXO + inhibitor + model group were added on the basis of the above experiments. Western blot analysis was performed to observe the effects of HUCMSC-EXO, inhibitor and both of them on HIF-1α and Bax expressions in HUVEC. Results HUCMSC-EXO was successfully extracted and identified. Compared with the control group, the volume of HUVEC in the model group and the HUCMSC-EXO group with different concentrations decreased, became round, connected and evacuated, and the growth state was poor under the inverted phase contrast microscope.CCK-8 detection showed that the cell viability in the HUCMSC-EXO group was significantly higher than that in the model group, the difference was statistically significant (t=9.23, P 0.05)and Bax protein ((0.363±0.069), (0.370±0.064); t=0.18, P>0.05). But both of them were down-regulated compared with the model group (HIF-1α protein (0.919±0.064), Bax protein (0.902±0.071)), the differences were significant( t=13.56, t=13.03, both P<0.05). Conclusion HUCMSC-EXO has a protective effect on OGD/R model of HUVEC, and its mechanism may be related to the down-regulation of HIF-1α expression. Key words: Human umbilical mesenchymal stem cells; Exosomes; Oxygen-glucose deprivation reoxygenation; Human umbilical venous endothelial cells; Apoptosis

HOTAIRM1 lncRNA is downregulated in clear cell renal cell carcinoma and inhibits the hypoxia pathway.

HOXA Transcript Antisense RNA, Myeloid-Specific 1 (HOTAIRM1) is a conserved long non-coding RNA (lncRNA) involved in myeloid and neural differentiation that is deregulated in acute myeloid leukemia and other cancers. Previous studies focused on the nuclear unspliced HOTAIRM1 transcript, however cytoplasmic splice variants exist whose roles have remained unknown. Here, we report novel functions of HOTAIRM1 in the kidney. HOTAIRM1 transcripts are induced during renal lineage differentiation of embryonic stem cells and required for expression of specific renal differentiation genes. We show that the major HOTAIRM1 transcript in differentiated cells is the spliced cytoplasmic HM1-3 isoform and that HM1-3 is downregulated in >90% of clear cell renal cell carcinomas (ccRCCs). Knockdown of HM1-3 in renal cells deregulates hypoxia-responsive and angiogenic genes, including ANGPTL4. Furthermore, HOTAIRM1 transcripts are downregulated by hypoxia-mimetic stress and knockdown of the cytoplasmic HM1-3 isoform in normoxic cells post-transcriptionally induces Hypoxia-Inducible Factor 1α (HIF1α) protein, a key activator of ANGPTL4. Our results demonstrate the pervasive downregulation of the specific HOTAIRM1 cytoplasmic isoform HM1-3 in ccRCC and suggest possible roles of HOTAIRM1 in kidney differentiation and suppression of HIF1-dependent angiogenic pathways.

Serum hypoxia-inducible factor-1α protein level as a diagnostic marker of obstructive sleep apnea.

Serum hypoxia-inducible factor-1α protein level as a diagnostic marker of obstructive sleep apnea.

Expressions of hypoxia inducible factor-1α and autophagy related protein Beclin-1 in colon cancer and their clinical significances

Objective To investigate the expressions of hypoxia inducible factor-1α (HIF-1α) and autophagy related protein Beclin-1 in colon cancer and their clinical significances. Methods From January 2017 to December 2018, 120 patients with colon cancer who were admitted to Dandong First Hospital were selected. The expressions of HIF-1α and Beclin-1 in colon cancer and corresponding adjacent tissues were detected by immunohistochemical SABC method. The relationship of the expressions of HIF-1α and Beclin-1 with the clinicopathological features of colon cancer patients was also discussed. The expressions of HIF-1α and Beclin-1 in 20 pairs of fresh colon cancer and paracancerous tissues were detected by Western blot. Results The results of immunohistochemistry showed that the positive expression rates of HIF-1α and Beclin-1 proteins in colon cancer tissues were significantly higher than those in paracancerous tissues [75.0% (90/120) vs. 21.7% (26/120), 60.8% (73/120) vs. 12.5% (15/120)], and the differences were statistically significant (χ 2 values were 68.343 and 60.359, both P 0.05). There was a positive correlation between the expressions of HIF-1α and Beclin-1 proteins in colon cancer (r = 0.483, P < 0.01). Conclusion The expressions of HIF-1α and Beclin-1 proteins in colon cancer tissues are significantly increased, and the interaction between them is involved in the occurrence and development of colon cancer. Key words: Colon neoplasms; Hypoxia-inducible factor 1, alpha subunit; Gene, Beclin-1; Autophagy

Flow-Encoded Oxygen Control to Track the Time-Dependence of Molecular Changes Induced by Static or Cycling Hypoxia

Detecting the effects of low oxygen on cell function is often dependent on monitoring the expression of a number of hypoxia markers. The time dependence of the appearance and stability of these markers varies between cell lines. Assessing cellular marker dynamics is also critical to determining how quickly cells respond to transient changes in oxygen levels that occurs with cycling hypoxia. We fabricated a manifold designed to use flow-encoding to produce sequential changes in gas mixtures delivered to a permeable-bottom 96-well plate. We show how this manifold and plate design can be used to expose cells to either static or cycling hypoxic conditions for eight different time periods thereby facilitating the study of the time-response of cells to altered oxygen environments. Using this device, we monitored the time-dependence of molecular changes in human PANC-1 pancreatic carcinoma and Caco-2 colon adenocarcinoma cells exposed to increasing periods of static or cycling hypoxia. Using immunohistochemistry, both cell lines show detectable levels of the marker protein hypoxia-inducible factor-1α (HIF-1α) after 3 h of exposure to static hypoxia. Cycling hypoxia increased the expression level of HIF-1α compared to static hypoxia. Both static and cycling hypoxia also increased glucose uptake and aldehyde dehydrogenase activity. This new device offers a facile screening approach to determine the kinetics of cellular alterations under varying oxygen conditions.

Inhibition of Obtusifolin on retinal pigment epithelial cell growth under hypoxia.

To explore the effect of Obtusifolin on retinal pigment epithelial cell growth under hypoxia. In vitro chemical hypoxia model of ARPE-19 cells was established using cobalt chloride (CoCl2). Cell viability was tested by cell counting kit-8 (CCK-8) assay. Western blot and real-time quantitative polymerase chain reaction were applied to detect proteins and mRNAs respectively. Flow cytometry was used to examine the cell cycle. Secretion of vascular endothelial growth factor (VEGF) was tested by using enzyme linked immunosorbent assay (ELISA). Under the chemical hypoxia model established by CoCl2, hypoxia inducible factor-1α (HIF-1α) mRNA and protein levels was up-regulated. Cell viability was increased and the proportion of S phase was higher. Obtusifolin could reduce cell viability under hypoxic conditions and arrest cells in G1 phase. Obtusifolin reduced the expression of Cyclin D1 and proliferating cell nuclear antigen (PCNA) in the hypoxic environment and increased the expression of p53 and p21. The levels of VEGF, VEGFR2 and eNOS proteins and mRNA were significantly increased under hypoxia while Obtusifolin inhibited the increasing. Obtusifolin can inhibit cell growth under hypoxic conditions and down-regulate HIF-1/VEGF/eNOS secretions in ARPE-19 cells.

Geometric characteristics of collagen have independent prognostic significance in breast ductal carcinoma in situ: an image analysis study

Collagen plays a key role in normal and malignant tissue homeostasis. While the prognostic significance of collagen fiber remodeling in invasive breast cancer has been studied, its role in ductal carcinoma in situ (DCIS) remains poorly defined. Using image analysis, we aimed to evaluate the prognostic significance of the geometric characteristics of collagen surrounding DCIS. A large well-characterized cohort of DCIS comprising pure DCIS (n = 610) and DCIS coexisting with invasive carcinoma (n = 180) were histochemically stained for collagen using picrosirius red. ImageJ software was used to assess collagen density, degree of collagen fiber dispersion and directionality in relation to DCIS ducts' boundary. We developed a collagen prognostic index and evaluated its prognostic significance. A poor index was observed in 24% of the pure DCIS and was associated with determinants of high-risk DCIS including higher nuclear grade, comedo type necrosis, hormonal receptor negativity, HER2 positivity and high proliferation index. High collagen prognostic index was associated with the collagen remodeling protein prolyl-4-hydroxlase alpha subunit 2 and the hypoxia-related protein hypoxia inducible factor 1α. DCIS coexisting with invasive breast cancer had a higher collagen prognostic index than pure DCIS ( p < 0.0001). High index was an independent poor prognostic factor for DCIS recurrence for all recurrences (HR = 2.3, p = 0.005) and just invasive recurrences (HR = 3.4, p = 0.003). Interaction between collagen prognostic index and radiotherapy showed that the index was associated with poor outcome even with adjuvant radiotherapy ( p = 0.0001). Collagen reorganization around DCIS is associated with poor outcome and provides a potential predictor for disease progression and resistance to radiotherapy. Mechanistic studies are warranted to decipher the underlying mechanisms.

Hydrogen sulfide improves vessel formation of the ischemic adductor muscle and wound healing in diabetic db/db mice.

Objective(s):It has been demonstrated that hydrogen sulfide plays a vital role in physiological and pathological processes such as regulating inflammation, oxidative stress, and vessel relaxation. The aim of the study was to explore the effect of hydrogen sulfide on angiogenesis in the ischemic adductor muscles of type 2 diabetic db/db mice and ischemic diabetic wound healing.Materials and Methods:The femoral arteries of diabetic db/db mice were isolated and ligated for preparation of ischemic hind limb model. Round incision was made on ischemic and non-ischemic limbs. The wounds were treated with sodium bisulfide (hydrogen sulfide donor). Real-time PCR and Western blotting were used to measure transcription of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), platelet derived growth factor (PDGF), hypoxia inducible factor-1α (HIF-1α) and endothelial nitric oxide synthase (eNOS) and protein expression of VEGF, VEGF receptor (VEGFR) and PDGF, PDGF receptor (PDGFR), respectively. Angiogenesis and morphological changes in adductor muscles were observed.Results:Hydrogen sulfide significantly increased transcription of VEGF, EGF, PDGF, HIF-1α, eNOS and protein expression of VEGF, PDGF, and phosphorylated VEGFR and PDGFR. Treatment with hydrogen sulfide significantly improved ischemic wound healing and formation of granulation tissue, and increased the number of small vessels in the ischemic adductor muscles.Conclusion:Our data suggested that hydrogen sulfide attenuated injury of ischemic adductor muscle, and promoted the ischemic diabetic wound healing via modulating angiogenesis in type 2 diabetic db/db mice.

Prediction of postoperative survival of triple-negative breast cancer based on nomogram model combined with expression of HIF-1α and c-myc.

The aims of this study were to explore the expression of hypoxia inducible factor-1α (HIF-1α) and c-myc protein in triple-negative breast cancer (TNBC) and its clinical prognostic significance, and to establish a prediction model for postoperative survival of TNBC based on nomogram.A total of 87 patients with TNBC at the Department of Breast Surgery, Beijing Chaoyang Hospital, Capital Medical University from January 2012 to December 2015 were enrolled in this study. Immunohistochemistry was performed to detect the expression of HIF-1α and c-myc protein in breast cancer tissues. Cox regression analyses were performed to explore the correlation between HIF-1α/c-myc expression and clinical pathological parameters as well as prognosis. Receiver-operating characteristic curve was generated for cox multivariate analysis. A nomogram was generated based on the cox multivariate analysis, and a calibration curve was prepared for the nomogram to evaluate the consistency between the predicted probability of the nomogram and the actual observed probability. The stability of nomogram model was validated with an external cohort including 39 TNBC patients.The positive expression rates of HIF-1α and c-myc protein in breast cancer tissues were 41.4% (36/87) and 55.2% (48/87), respectively. HIF-1α expression was significantly correlated with age, tumor diameter, histological grade, lymph node status, and tumor TNM stage; c-myc expression was significantly associated with tumor diameter, histological grade, lymph node status, and tumor TNM stage. Cox univariate and multivariate analyses showed that HIF-1α and c-myc protein expression, histological grade, lymph node status, and tumor TNM stage were the independent risk factors for postoperative survival in TNBC patients. The AUC of prediction model was 0.843 (0.809–0.887). The nomogram could predict the probability of 3-year disease-free survival according to each patient's condition. The calibration curve displayed good agreement of the predicted probability with the actual observed probability, indicating that the nomogram model had great value of prediction. The external validation indicated the prediction model had good stability.HIF-1α-positive expression, c-myc positive expression, histological grade III, lymph node positive, and TNM stage III tumors suggested that TNBC patients had a poor prognosis. This prediction model can be used to predict postoperative survival of TNBC.

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.

The use of TLR2 modified BMSCs for enhanced bone regeneration in the inflammatory micro-environment

The repair of periodontal bone tissue defects in patients with periodontitis is one of the major challenges for dentists. Stem cell-based bone regeneration has been considered as a promising strategy to restore the lost periodontal bone tissue. However, the local inflammatory environment of periodontal tissue affects stem cell-based periodontal bone regeneration. Toll-like receptor 2 (TLR2), a member of the TLR family, plays an important role in regulating immunoreaction. Previous studies have shown that the activation of TLR2 signaling pathway is involved in enhancing tissue vascularization and wound healing. However, the mechanisms underlying the therapeutic effects of TLR2 on regulating bone marrow stromal cells (BMSCs) mediated periodontal bone tissue regeneration still need to be further investigated. In this study, we tested the effect of TLR2 on regulating BMSCs mediated alveolar bone regeneration by establishing a TLR2 gene-modified canine BMSCs using a lentivirus. Activation of TLR2 significantly enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and bone morphogenetic protein 2 (BMP-2) and then upregulated the expression of their downstream osteogenic and angiogenic related gene in BMSCs. TLR2-BMSCs mediated bone regeneration in canine tooth extraction sockets under an inflammatory environment demonstrated that activation of the TLR2 signaling pathway significantly stimulated BMSCs meditated angiogenesis and osteogenesis.