Metabolic reprogramming is a common phenomenon in cancer, with aerobic glycolysis being one of its important characteristics. Hypoxia-inducible factor-1α (HIF1Α) is thought to play an important role in aerobic glycolysis. Meanwhile, naringin is a natural flavanone glycoside derived from grapefruits and many other citrus fruits. In this work, we identified glycolytic genes related to HIF1Α by analyzing the colon cancer database. The analysis of extracellular acidification rate and cell function verified the regulatory effects of HIF1Α overexpression on glycolysis, and the proliferation and migration of colon cancer cells. Moreover, naringin was used as an inhibitor of colon cancer cells to illustrate its effect on HIF1Α function. The results showed that the HIF1Α and enolase 2 (ENO2) levels in colon cancer tissues were highly correlated, and their high expression indicated a poor prognosis for colon cancer patients. Mechanistically, HIF1Α directly binds to the DNA promoter region and upregulates the transcription of ENO2; ectopic expression of ENO2 increased aerobic glycolysis in colon cancer cells. Most importantly, we found that the appropriate concentration of naringin inhibited the transcriptional activity of HIF1Α, which in turn decreased aerobic glycolysis in colon cancer cells. Generally, naringin reduces glycolysis in colon cancer cells by reducing the transcriptional activity of HIF1Α and the proliferation and invasion of colon cancer cells. This study helps to elucidate the relationship between colon cancer progression and glucose metabolism, and demonstrates the efficacy of naringin in the treatment of colon cancer.
Glycolysis ; Colonic Neoplasms/metabolism* ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Phosphopyruvate Hydratase/metabolism* ; Flavanones/pharmacology* ; Cell Line, Tumor ; Databases, Genetic ; Cell Proliferation/drug effects* ; Transfection ; Warburg Effect, Oncologic

OBJECTIVE: To investigate the the effects of leptin on the proliferation, differentiation and PTEN expression of rat retinal progenitor cells (RPCs) cultured under hypoxic condition. METHODS: SD rat RPCs were cultured in normoxic conditions or exposed to hypoxia in the presence of 0, 0.3, 1.0, 3.0, 10, and 30 nmol/L leptin for 12, 48 and 72 h, and the cell viability was assessed using cell counting kit 8 (CCK 8) assay. The RPCs in primary culture were divided into control group, hypoxia group, and hypoxia+leptin group, and after 48 h of culture, the cell medium was replaced with differentiation medium and the cells were further cultured for 6 days. Immunofluorescence staining was employed to detect the cells positive for β-tubulin III and GFAP, and Western blotting was used to examine the expression of PTEN at 48 h of cell culture. RESULTS: The first generation of RPCs showed suspended growth in the medium with abundant and bright cellular plasma and formed mulberry like cell spheres after 2 days of culture. Treatment with low-dose leptin (below 3.0 nmol/L) for 48 h obviously improved the viability of RPCs cultured in hypoxia, while at high concentrations (above 10 nmol/L), leptin significantly suppressed the cell viability (P < 0.05). The cells treated with 3.0 nmol/L leptin for 48 h showed the highest viability (P < 0.05). After treatment with 3.0 nmol/L leptin for 48 h, the cells with hypoxic exposure showed similar GFAP and β-tubulin Ⅲ positivity with the control cells (P>0.05), but exhibited an obvious down-regulation of PTEN protein expression compared with the control cells (P < 0.05). CONCLUSION In rat RPCs with hypoxic exposure, treatment with low dose leptin can promote the cell proliferation and suppress cellular PTEN protein expression without causing significant effects on cell differentiation.
Animals ; Cell Differentiation/drug effects* ; Cell Hypoxia/drug effects* ; Cell Proliferation/drug effects* ; Cells, Cultured ; Leptin/pharmacology* ; PTEN Phosphohydrolase/metabolism* ; Rats ; Rats, Sprague-Dawley ; Retina/metabolism* ; Stem Cells/metabolism* ; Tubulin

OBJECTIVE: To investigate the effect of periostin on hypoxia-induced oxidative stress and apoptosis in human periodontal ligament fibroblasts and the molecular mechanism involved. METHODS: cultured human periodontal ligament fibroblasts were placed in an anaerobic gas-producing bag for hypoxia treatment for 48 h followed by treatment with periostin at low (25 ng/mL), moderate (50 ng/mL) or high (100 ng/mL) doses. MTT assay was used to measure the cell viability, and the cell apoptosis rate was determined using flow cytometry. The contents of IL-1β, IL-6 and TNF-α in the cells were determined with ELISA, and ROS levels were measured using a fluorescent plate reader. The intracellular SOD activity was detected using ELISA. The expressions of HIF-1α, P21, cyclin D1, Bax, cleaved caspase-3, Bcl-2, P38MAPK and p-p38 MAPK proteins in the cells were detected with Western blotting. RESULTS: Hypoxia treatment significantly reduced the cell viability ( < 0.05), increased P21, Bax, and cleaved caspase-3 protein levels ( < 0.05), promoted cell apoptosis ( < 0.05), and decreased cyclin D1 and Bcl-2 protein levels ( < 0.05) in the cells. Compared with the hypoxic group, the cells treated with periostin at different concentrations showed significantly increased cell viability ( < 0.05) with significantly lowered apoptotic rates ( < 0.05) and decreased expression levels of Bax and cleaved caspase-3 ( < 0.05) but significantly increased expression levels of cyclin D1 and Bcl-2 ( < 0.05). Hypoxic exposure of the cells resulted in significantly increased expression levels of HIF-1α and p-p38 MAPK ( < 0.05) and increased levels of IL-1β, IL-6, TNF-α and ROS ( < 0.05) but decreased SOD activity ( < 0.05). Periostin treatment at different concentrations significantly lowered the expression levels of HIF-1α and p-p38 MAPK ( < 0.05) and the levels of IL-1β, IL-6, TNF-α and ROS ( < 0.05) and significantly increased SOD activity in the hypoxic cells ( < 0.05). CONCLUSIONS Periostin promotes the proliferation, inhibits apoptosis, enhances cellular antioxidant capacity, and reduces inflammatory damage in human periodontal ligament fibroblasts exposed to hypoxia possibly by inhibiting the activation of the p38 MAPK signaling pathway.
Apoptosis ; drug effects ; Cell Adhesion Molecules ; administration & dosage ; Cell Hypoxia ; Fibroblasts ; drug effects ; Humans ; Oxidative Stress ; drug effects ; Periodontal Ligament ; cytology ; Signal Transduction ; drug effects ; p38 Mitogen-Activated Protein Kinases

OBJECTIVE: To investigate the effects of salvianolic acid A (SAA) on cardiomyocyte apoptosis and mitochondrial dysfunction in response to hypoxia/reoxygenation (H/R) injury and to determine whether the Akt signaling pathway might play a role. METHODS: An in vitro model of H/R injury was used to study outcomes on primary cultured neonatal rat cardiomyocytes. The cardiomyocytes were treated with 12.5, 25, 50 μg/mL SAA at the beginning of hypoxia and reoxygenation, respectively. Adenosine triphospate (ATP) and reactive oxygen species (ROS) levels were assayed. Cell apoptosis was evaluated by flow cytometry and the expression of cleaved-caspase 3, Bax and Bcl-2 were detected by Western blotting. The effects of SAA on mitochondrial dysfunction were examined by determining the mitochondrial membrane potential (△Ψm) and mitochondrial permeability transition pore (mPTP), followed by the phosphorylation of Akt (p-Akt) and GSK-3β (p-GSK-3β), which were measured by Western blotting. RESULTS: SAA significantly preserved ATP levels and reduced ROS production. Importantly, SAA markedly reduced the number of apoptotic cells and decreased cleaved-caspase 3 expression levels, while also reducing the ratio of Bax/Bcl-2. Furthermore, SAA prevented the loss of △Ψm and inhibited the activation of mPTP. Western blotting experiments further revealed that SAA significantly increased the expression of p-Akt and p-GSK-3β, and the increase in p-GSK-3β expression was attenuated after inhibition of the Akt signaling pathway with LY294002. CONCLUSION SAA has a protective effect on cardiomyocyte H/R injury; the underlying mechanism may be related to the preservation of mitochondrial function and the activation of the Akt/GSK-3β signaling pathway.
Adenosine Triphosphate ; analysis ; Animals ; Animals, Newborn ; Caffeic Acids ; pharmacology ; Cell Hypoxia ; Cells, Cultured ; Glycogen Synthase Kinase 3 beta ; physiology ; Lactates ; pharmacology ; Mitochondria, Heart ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; drug effects ; Myocytes, Cardiac ; drug effects ; Proto-Oncogene Proteins c-akt ; physiology ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism ; Signal Transduction ; physiology

OBJECTIVE: To evaluate the effects of Celastrus Orbiculatus extracts (COE) on metastasis in hypoxia-induced hepatocellular carcinoma cells (HepG2) and to explore the underlying molecular mechanisms. METHODS: The effect of COE (160, 200 and 240 µ g/mL) on cell viability, scratch-wound, invasion and migration were studied by 3-4,5-dimethyl-2-thiazolyl-2,5-diphenyl-2-H-tetrazolium bromide (MTT), scratch-wound and transwell assays, respectively. CoCl was used to establish a hypoxia model in vitro. Effects of COE on the expressions of E-cadherin, vimentin and N-cadherin were investigated with Western blot and immunofluorescence analysis, respectively. RESULTS: COE inhibited proliferation and metastasis of hypoxia-induced hepatocellular carcinoma cells in a dose-dependent manner (P<0.01). Furthermore, the expression of epithelial-mesenchymal transition (EMT) related markers were also remarkably suppressed in a dose-dependent manner (P<0.01). In addition, the upstream signaling pathways, including the hypoxia-inducible factor 1 α (Hif-1 α) and Twist1 were suppressed by COE. Additionally, the Hif-1 α inhibitor 3-5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), potently suppressed cell invasion and migration as well as expression of EMT in hypoxia-induced HepG2 cells. Similarly, the combined treatment with COE and YC-1 showed a synergistic effect (P<0.01) compared with the treatment with COE or YC-1 alone in hypoxia-induced HepG2 cells. CONCLUSIONS COE significantly inhibited the tumor metastasis and EMT by suppressing Hif-1 α/Twist1 signaling pathway in hypoxia-induced HepG2 cell. Thus, COE might have potential effect to inhibit the progression of HepG2 in the context of tumor hypoxia.
Biomarkers, Tumor ; metabolism ; Carcinoma, Hepatocellular ; drug therapy ; pathology ; Celastrus ; chemistry ; Cell Hypoxia ; drug effects ; Cell Proliferation ; drug effects ; Cell Shape ; drug effects ; Cobalt ; Down-Regulation ; drug effects ; Epithelial-Mesenchymal Transition ; drug effects ; Hep G2 Cells ; Humans ; Liver Neoplasms ; drug therapy ; pathology ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Neoplasm Proteins ; metabolism ; Plant Extracts ; pharmacology ; therapeutic use ; Signal Transduction ; drug effects

Astragaloside Ⅳ(AS-Ⅳ) has protective effects against ischemia-reperfusion injury(IRI), but its mechanism of action has not yet been determined. This study aims to investigate the protective effects and mechanism of AS-Ⅳ on H9c2 cardiomyocyte injury induced by hypoxia-reoxygenation(H/R). The H/R model of myocardial cells was established by hypoxic culture for 12 hours and then reoxygenation culture for 8 hours. After AS-Ⅳ treatment, cell viability, the reactive oxygen species(ROS) levels, as well as the content or activity of superoxide dismutase(SOD), malondialdehyde(MDA), interleukin 6(IL-6), and tumor necrosis factor alpha(TNF-α), were measured to evaluate the effect of AS-Ⅳ treatment. The effect of AS-Ⅳ on HO-1 protein expression and nuclear Nrf2 and Bach1 protein expression was determined by Western blot. Finally, siRNA was used to knock down HO-1 gene expression to observe its reversal effect on AS-Ⅳ intervention. The results showed that as compared with the H/R model group, the cell viability was significantly increased(P<0.01), ROS level in the cells, MDA, hs-CRP and TNF-α in cell supernatant and nuclear protein Bach1 expression in the cells were significantly decreased(P<0.01), while SOD content, HO-1 protein expression in cells and expression of nuclear protein Nrf2 were significantly increased(P<0.01) in H/R+AS-Ⅳ group. However, pre-transfection of HO-1 siRNA into H9c2 cells by liposome could partly reverse the above effects of AS-Ⅳ after knocking down the expression of HO-1. This study suggests that AS-Ⅳ has significant protective effect on H/R injury of H9c2 cardiomyocytes, and Nrf2/Bach1/HO-1 signaling pathway may be a key signaling pathway for the effect.
Apoptosis ; Basic-Leucine Zipper Transcription Factors ; metabolism ; Cell Hypoxia ; Cells, Cultured ; Heme Oxygenase-1 ; metabolism ; Humans ; Myocytes, Cardiac ; drug effects ; NF-E2-Related Factor 2 ; metabolism ; Saponins ; pharmacology ; Signal Transduction ; Triterpenes ; pharmacology

OBJECTIVE: To investigate the effect of G protein-coupled receptor 17 (GPR17) on hypoxia injury in retinal ganglion cells . METHODS: CoCl (400 μmol/L) was used to induce hypoxic injury in RGC-5 cells. The expression of GPR17 and the effect of GPR17 ligands were investigated, and the role of GPR17 in hypoxia injury was further studied by transfection of RGC-5 cells with GPR17 small interfering RNA (siRNA). The cell viability was determined by MTT and the cell apoptosis rate was detected by flow cytometry analysis. The expression of GPR17 mRNA was determined with RT-PCR. RESULTS: mRNA expressions of GPR17 in RGC-5 cells with and without CoCl treatment were 0.36±0.05 and 0.26±0.08(<0.01). Compared with hypoxia without any treatment, pretreatment with GPR17 agonists (LTD, UDP, UDP-G) significantly reduced cell viability (the survival rates of cells decreased by 29.6%, 31.8% and 33.9%, all <0.01), while the effect of GPR17 antagonist (cangrelor) was the opposite (the survival rates of cells increased by 33.2%, <0.01). Transfection with GPR17 SiRNA inhibited hypoxia-induced up-expression of GPR17 mRNA (<0.01)and reduced cell apoptosis[rates of cell apoptosis were(39.73±2.06)%,(42.50±3.64)% and (24.98±2.16)% for blank control, NC siRNA and GPR17 siRNA groups, <0.01]. CONCLUSIONS GPR17 may mediate hypoxia injury in RGC-5 cells, while the knockdown of GPR17 can reduce the hypoxia injury.
Apoptosis ; Cell Hypoxia ; genetics ; Cell Line ; Cell Survival ; Cobalt ; Gene Expression Regulation ; drug effects ; Gene Knockdown Techniques ; Humans ; Hypoxia ; chemically induced ; genetics ; Receptors, G-Protein-Coupled ; genetics ; metabolism ; Retinal Ganglion Cells ; drug effects

OBJECTIVETo investigate the effect of telomerase activation on biological behaviors of neural stem cells after hypoxic-ischemic insults.

METHODSThe neural stem cells passaged in vitro were divided into four groups: control, oxygen-glucose deprivation (OGD), OGD+cycloastragenol (CAG) high concentration (final concentration of 25 μM), and OGD+CAG low concentration (final concentration of 10 μM). The latter three groups were subjected to OGD. Telomerase reverse transcriptase (TERT) expression level was evaluated by Western blot. Telomerase activity was detected by telomerase repeat amplification protocol (TRAP). Cell number and neural sphere diameter were measured under a microscope. The activity of lactate dehydrogenase (LDH) was examined by chemiluminescence. Cell proliferation rate and apoptosis were detected by flow cytometry.

RESULTSAfter OGD insults, obvious injury of neural stem cells was observed, including less cell number, smaller neural sphere, more dead cells, lower proliferation rate and decreased survival rate. In CAG-treated groups, there were higher TERT expression level and telomerase activity compared with the control group (P<0.05). In comparison with the OGD group, CAG treatment attenuated cell loss (P<0.05) and neural sphere diameter decrease (P<0.05), promoted cell proliferation (P<0.05), and increased cell survival rate (P<0.05). Low and high concentrations of CAG had similar effects on proliferation and survival of neural stem cells (P>0.05). In the normal cultural condition, CAG treatment also enhanced TERT expression (P<0.05) and increased cell numbers (P<0.05) and neural sphere diameter (P<0.05) compared with the control group.

CONCLUSIONSTelomerase activation can promote the proliferation and improve survival of neural stem cells under the state of hypoxic-ischemic insults, suggesting telomerase activators might be potential agents for the therapy of hypoxic-ischemic brain injury.

Animals ; Cell Survival ; drug effects ; Enzyme Activation ; Hypoxia-Ischemia, Brain ; etiology ; Neural Stem Cells ; drug effects ; physiology ; Rats ; Sapogenins ; pharmacology ; Telomerase ; physiology

Adipose tissue hypoxia has been recognized as the initiation of insulin resistance syndromes. The aim of the present study was to investigate the effects of mangiferin on the insulin signaling pathway and explore whether mangiferin could ameliorate insulin resistance caused by hypoxia in adipose tissue. Differentiated 3T3-L1 adipocytes were incubated under normal and hypoxic conditions, respectively. Protein expressions were analyzed by Western blotting. Inflammatory cytokines and HIF-1-dependent genes were tested by ELISA and q-PCR, respectively. The glucose uptake was detected by fluorescence microscopy. HIF-1α was abundantly expressed during 8 h of hypoxic incubation. Inflammatory reaction was activated by up-regulated NF-κB phosphorylation and released cytokines like IL-6 and TNF-α. Glucose uptake was inhibited and insulin signaling pathway was damaged as well. Mangiferin substantially inhibited the expression of HIF-1α. Lactate acid and lipolysis, products released by glycometabolism and lipolysis, were also inhibited. The expression of inflammatory cytokines was significantly reduced and the damaged insulin signaling pathway was restored to proper functional level. The glucose uptake of hypoxic adipocytes was promoted and the dysfunction of adipocytes was relieved. These results showed that mangiferin could not only improve the damaged insulin signaling pathway in hypoxic adipocytes, but also ameliorate inflammatory reaction and insulin resistance caused by hypoxia.
3T3-L1 Cells ; Adipocytes ; drug effects ; immunology ; Adipokines ; genetics ; immunology ; Animals ; Cell Hypoxia ; drug effects ; Glucose ; metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; immunology ; Insulin ; metabolism ; Insulin Resistance ; Mice ; NF-kappa B ; genetics ; immunology ; Oxygen ; metabolism ; Tumor Necrosis Factor-alpha ; genetics ; immunology ; Xanthones ; pharmacology

Considering the great potential of natural products as anticancer agents, the present study was designed to explore the molecular mechanisms responsible for anticancer activities of Mesua ferrea stem bark extract against human colorectal carcinoma. Based on MTT assay results, bioactive sub-fraction (SF-3) was selected for further studies using HCT 116 cells. Repeated column chromatography resulted in isolation of less active α-amyrin from SF-3, which was identified and characterized by GC-MS and HPLC methods. α-amyrin and betulinic acid contents of SF-3 were measured by HPLC methods. Fluorescent assays revealed characteristic apoptotic features, including cell shrinkage, nuclear condensation, and marked decrease in mitochondrial membrane potential in SF-3 treated cells. In addition, increased levels of caspases-9 and -3/7 levels were also observed in SF-3 treated cells. SF-3 showed promising antimetastatic properties in multiple in vitro assays. Multi-pathway analysis revealed significant down-regulation of WNT, HIF-1α, and EGFR with simultaneous up-regulation of p53, Myc/Max, and TGF-β signalling pathways in SF-3 treated cells. In addition, promising growth inhibitory effects were observed in SF-3 treated HCT 116 tumour spheroids, which give a hint about in vivo antitumor efficacy of SF-3 phytoconstituents. In conclusion, these results demonstrated that anticancer effects of SF-3 towards colon cancer are through modulation of multiple molecular pathways.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Colorectal Neoplasms ; drug therapy ; metabolism ; pathology ; physiopathology ; ErbB Receptors ; genetics ; metabolism ; HCT116 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Magnoliopsida ; chemistry ; Neoplasm Metastasis ; prevention & control ; Plant Bark ; chemistry ; Plant Extracts ; pharmacology ; Signal Transduction ; drug effects ; Wnt Proteins ; genetics ; metabolism