scholarly journals Acute vs. Chronic vs. Cyclic Hypoxia: Their Differential Dynamics, Molecular Mechanisms, and Effects on Tumor Progression

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 339 ◽  
Author(s):  
Saxena ◽  
Jolly
Keyword(s):  
Tumor Progression ◽  
Intermittent Hypoxia ◽  
Molecular Mechanisms ◽  
Total Duration ◽  
Adaptation To Hypoxia ◽  
Hallmarks Of Cancer ◽  
Obstructive Sleep ◽  
Risk Of Cancer

Hypoxia has been shown to increase the aggressiveness and severity of tumor progression. Along with chronic and acute hypoxic regions, solid tumors contain regions of cycling hypoxia (also called intermittent hypoxia or IH). Cyclic hypoxia is mimicked in vitro and in vivo by periodic exposure to cycles of hypoxia and reoxygenation (H–R cycles). Compared to chronic hypoxia, cyclic hypoxia has been shown to augment various hallmarks of cancer to a greater extent: angiogenesis, immune evasion, metastasis, survival etc. Cycling hypoxia has also been shown to be the major contributing factor in increasing the risk of cancer in obstructive sleep apnea (OSA) patients. Here, we first compare and contrast the effects of acute, chronic and intermittent hypoxia in terms of molecular pathways activated and the cellular processes affected. We highlight the underlying complexity of these differential effects and emphasize the need to investigate various combinations of factors impacting cellular adaptation to hypoxia: total duration of hypoxia, concentration of oxygen (O2), and the presence of and frequency of H–R cycles. Finally, we summarize the effects of cycling hypoxia on various hallmarks of cancer highlighting their dependence on the abovementioned factors. We conclude with a call for an integrative and rigorous analysis of the effects of varying extents and durations of hypoxia on cells, including tools such as mechanism-based mathematical modelling and microfluidic setups.

scholarly journals Intermittent Hypoxia-Induced Activation of Endothelial Cells Is Mediated via Sympathetic Activation-Dependent Catecholamine Release

2021 ◽  
Vol 12 ◽  
Author(s):  
Rengul Cetin-Atalay ◽  
Angelo Y. Meliton ◽  
David Wu ◽  
Parker S. Woods ◽  
Kaitlyn A. Sun ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Adult Population ◽  
Cardiovascular Effects ◽  
Catecholamine Release ◽  
Obstructive Sleep ◽  
Underlying Mechanisms ◽  
Circulating Levels ◽  
Pharmacologic Inhibition

Obstructive sleep apnea (OSA) is a common breathing disorder affecting a significant percentage of the adult population. OSA is an independent risk factor for cardiovascular disease (CVD); however, the underlying mechanisms are not completely understood. Since the severity of hypoxia correlates with some of the cardiovascular effects, intermittent hypoxia (IH) is thought to be one of the mechanisms by which OSA may cause CVD. Here, we investigated the effect of IH on endothelial cell (EC) activation, characterized by the expression of inflammatory genes, that is known to play an important role in the pathogenesis of CVD. Exposure of C57BL/6 mice to IH led to aortic EC activation, while in vitro exposure of ECs to IH failed to do so, suggesting that IH does not induce EC activation directly, but indirectly. One of the consequences of IH is activation of the sympathetic nervous system and catecholamine release. We found that exposure of mice to IH caused elevation of circulating levels of catecholamines. Inhibition of the IH-induced increase in catecholamines by pharmacologic inhibition or by adrenalectomy or carotid body ablation prevented the IH-induced EC activation in mice. Supporting a key role for catecholamines, epinephrine alone was sufficient to cause EC activation in vivo and in vitro. Together, these results suggested that IH does not directly induce EC activation, but does so indirectly via release of catecholamines. These results suggest that targeting IH-induced sympathetic nerve activity and catecholamine release may be a potential therapeutic target to attenuate the CV effects of OSA.

LINC00152 promotes Ovarian tumor progression and Predicts Poor Prognosis by inhibiting the  ubiquitination of BCL6

2020 ◽  
Author(s):  
Shunni Wang ◽  
Weiwei Weng ◽  
Tingting Chen ◽  
Midie Xu ◽  
Ping Wei ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Tumor Progression ◽  
Protein Interactions ◽  
Ovarian Tumor ◽  
Molecular Mechanisms ◽  
Tumor Proliferation ◽  
In Vivo Experiments ◽  
Rna Immunoprecipitation

Abstract Background : Long non-coding RNA 00152 (LINC00152) has been found oncogenic in multiple somatic malignancies. But its roles in the ovarian cancer remain elusive. We aim to investigate its functions and mechanism in the ovarian tumor progression. Methods: We used RNAscope and RT-qPCR assays to detect the LINC00152 levels in 152 pairs of ovarian tumor and paratumorous tissues, conducted in vitro and in vivo experiments to evaluate its biological functions, and performed RNA immunoprecipitation, RNA-pulldown, MS/LS analysis, mutant construction and ubiquitination assays to explore the LINC00152-BCL6 binding and regulation. Results: LINC00152 was abnormally increased in the ovarian tumor tissues and its high expression predicted poorer survivals of patients; overexpression of LINC00152 promoted ovarian tumor proliferation and metastasis both in vitro and in vivo ; LINC00152 bond to Serine333 and Serine343 of BCL6 and then suppressed its ubiquitination; Finally, LINC00152 facilitated its oncogenic functions in a BCL6-mediated manner in ovarian cancer. Conclusions: LINC00152 is the independent prognostic predictor of ovarian cancer; and the abnormal expression of LINC00152 facilitates ovarian tumor proliferation and invasion by suppress the ubiquitination of BCL6. Our data might be helpful in exploring the molecular mechanisms of lncRNA-protein interactions, and might provide the potential target for the tumor pharmacology of ovarian cancer.

VE-Cadherin cleavage in sleep apnoea: new insights into intermittent hypoxia-related endothelial permeability

2021 ◽  
pp. 2004518
Author(s):  
Olfa Harki ◽  
Renaud Tamisier ◽  
Jean-Louis Pépin ◽  
Sébastien Bailly ◽  
Anissa Mahmani ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Tyrosine Kinases ◽  
Intermittent Hypoxia ◽  
Endothelial Permeability ◽  
Sleep Apnoea ◽  
Cellular Mechanisms ◽  
Atherosclerosis Progression ◽  
Obstructive Sleep

BackgroundObstructive Sleep Apnoea (OSAS) causes intermittent hypoxia (IH) that in turn induces endothelial dysfunction and atherosclerosis progression. We hypothesized that VE-Cadherin cleavage, detected by its released extracellular fragment solubilised in the blood (sVE), may be an early indicator of emergent abnormal endothelial permeability. Our aim was to assess VE-cadherin cleavage in OSAS patients and in in vivo and in vitro IH models to decipher the cellular mechanisms and consequences.MethodsSera from 7 healthy volunteers exposed to fourteen nights of IH, 43 OSAS patients and 31 healthy control subjects were analysed for their sVE content. Human aortic endothelial cells (HAEC) were exposed to 6 h of IH in vitro, with or without an antioxidant or inhibitors of HIF-1, tyrosine kinases or VEGF pathways. VE-Cadherin cleavage and phosphorylation were evaluated, and endothelial permeability was assessed by measuring trans-endothelial electrical resistance (TEER) and FITC-Dextran flux.ResultssVE was significantly elevated in sera from healthy volunteers submitted to IH and OSAS patients before treatment, but conversely, decreased in OSAS patients after 6 months of continuous positive airway pressure treatment. OSAS was the main factor accounting for sVE variations in a multivariate analysis. In in vitro experiments, cleavage and expression of VE-Cadherin increased upon HAEC exposure to IH. TEER decreased and FITC-Dextran flux increased. These effects were reversed by all the pharmacological inhibitors tested.ConclusionWe suggest that in OSAS, IH increases endothelial permeability in OSAS by inducing VE-Cadherin cleavage through ROS production and activation of HIF-1, VEGF and tyrosine kinase pathways.

scholarly journals Cell-Selective Altered Cargo Properties of Extracellular Vesicles Following In Vitro Exposures to Intermittent Hypoxia

2021 ◽  
Vol 22 (11) ◽  
pp. 5604
Author(s):  
David Sanz-Rubio ◽  
Abdelnaby Khalyfa ◽  
Zhuanhong Qiao ◽  
Jorge Ullate ◽  
José M. Marin ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Extracellular Vesicles ◽  
Intermittent Hypoxia ◽  
Adverse Outcomes ◽  
Metabolic Dysfunction ◽  
Cellular Effects ◽  
Obstructive Sleep ◽  
Cell Sources

Intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), is associated with cardiovascular and metabolic dysfunction. However, the mechanisms underlying these morbidities remain poorly delineated. Extracellular vesicles (EVs) mediate intercellular communications, play pivotal roles in a multitude of physiological and pathological processes, and could mediate IH-induced cellular effects. Here, the effects of IH on human primary cells and the release of EVs were examined. Microvascular endothelial cells (HMVEC-d), THP1 monocytes, THP1 macrophages M0, THP1 macrophages M1, THP1 macrophages M2, pre-adipocytes, and differentiated adipocytes (HAd) were exposed to either room air (RA) or IH for 24 h. Secreted EVs were isolated and characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. The effects of each of the cell-derived EVs on endothelial cell (EC) monolayer barrier integrity, on naïve THP1 macrophage polarity, and on adipocyte insulin sensitivity were also evaluated. IH did not alter EVs cell quantal release, but IH-EVs derived from HMVEC-d (p < 0.01), THP1 M0 (p < 0.01) and HAd (p < 0.05) significantly disrupted HMVEC-d monolayer integrity, particularly after H2O2 pre-conditioning. IH-EVs from HMVEC-d and THP1 M0 elicited M2-polarity changes did not alter insulin sensitivity responses. IH induces cell-selective changes in EVs cargo, which primarily seem to target the emergence of endothelial dysfunction. Thus, changes in EVs cargo from selected cell sources in vivo may play causal roles in some of the adverse outcomes associated with OSA.

scholarly journals Intermittent hypoxia mediated by TSP1 dependent on STAT3 induces cardiac fibroblast activation and cardiac fibrosis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Qiankun Bao ◽  
Bangying Zhang ◽  
Ya Suo ◽  
Chen Liu ◽  
Qian Yang ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Cardiac Fibrosis ◽  
Synergistic Effects ◽  
Cardiac Fibroblasts ◽  
Cardiac Fibroblast ◽  
Ang Ii ◽  
Fibroblast Activation ◽  
Obstructive Sleep

Intermittent hypoxia (IH) is the predominant pathophysiological disturbance in obstructive sleep apnea (OSA), known to be independently associated with cardiovascular diseases. However, the effect of IH on cardiac fibrosis and molecular events involved in this process are unclear. Here, we tested IH in angiotensin II (Ang II)-induced cardiac fibrosis and signaling linked to fibroblast activation. IH triggered cardiac fibrosis and aggravated Ang II-induced cardiac dysfunction in mice. Plasma thrombospondin-1 (TSP1) content was upregulated in both IH-exposed mice and OSA patients. Moreover, both in vivo and in vitro results showed IH-induced cardiac fibroblast activation and increased TSP1 expression in cardiac fibroblasts. Mechanistically, phosphorylation of STAT3 at Tyr705 mediated the IH-induced TSP1 expression and fibroblast activation. Finally, STAT3 inhibitor S3I-201 or AAV9 carrying a periostin promoter driving the expression of shRNA targeting Stat3 significantly attenuated the synergistic effects of IH and Ang II on cardiac fibrosis in mice. This work suggests a potential therapeutic strategy for OSA-related fibrotic heart disease.

scholarly journals Onco-Preventive and Chemo-Protective Effects of Apple Bioactive Compounds

Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 4025
Author(s):  
Linda Nezbedova ◽  
Tony McGhie ◽  
Mark Christensen ◽  
Julian Heyes ◽  
Noha Ahmed Nasef ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Causes Of Death ◽  
Epidemiological Studies ◽  
In Vivo Studies ◽  
Protective Effects ◽  
Plant Metabolites ◽  
Hallmarks Of Cancer ◽  
Secondary Plant Metabolites

Cancer is one of the leading causes of death globally. Epidemiological studies have strongly linked a diet high in fruits to a lower incidence of cancer. Furthermore, extensive research shows that secondary plant metabolites known as phytochemicals, which are commonly found in fruits, have onco-preventive and chemo-protective effects. Apple is a commonly consumed fruit worldwide that is available all year round and is a rich source of phytochemicals. In this review, we summarize the association of apple consumption with cancer incidence based on findings from epidemiological and cohort studies. We further provide a comprehensive review of the main phytochemical patterns observed in apples and their bioavailability after consumption. Finally, we report on the latest findings from in vitro and in vivo studies highlighting some of the key molecular mechanisms targeted by apple phytochemicals in relation to inhibiting multiple ‘hallmarks of cancer’ that are important in the progression of cancer.

scholarly journals LncRNA NKX2-1-AS1 As ceRNA Promotes Tumor Progression and Angiogenesis by Upregulating SERPINE1 Expression and Activating VEGFR-2 Signaling Pathway in Gastric Cancer

2020 ◽  
Author(s):  
Fei Teng ◽  
Juxiang Zhang ◽  
Yi Chen ◽  
Xiaodong Shen ◽  
Yanjiao Guo ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Progression ◽  
Molecular Mechanisms ◽  
Luciferase Assay ◽  
Luciferase Reporter ◽  
Mechanistic Study ◽  
Tumor Tissues ◽  
Vegfr2 Signaling

Abstract Background: Recent evidence indicated that the lncRNA NKX2-1-AS1 (NKX2-1 antisense RNA 1) plays an important role in cancer progression and metastasis. However, the associated molecular mechanisms of NKX2-1-AS1 in GC are still unclear. Methods: To determine the target of the study by bioinformatic analysis. NKX2-1-AS1 expression was measured in paired tumor and non-tumor tissues of 178 GC patients, by quantitative reverse transcription PCR. The in vitro and in vivo biological functions of NKX2-1-AS1 were examined by loss-of-function and gain-of-function experiments. The potential mechanisms of this competing endogenous RNA (ceRNA) were elucidated using dual-luciferase reporter assay, quantitative PCR, Western blot, and fluorescence in situ hybridization (FISH). Results: NKX2-1-AS1 expression was upregulated in GC cell lines and tumor tissues, which was correlated with tumor progression and enhanced angiogenesis. Functionally, NKX2-1-AS1 overexpression promoted GC cell proliferation, metastasis, invasion, and angiogenesis, while NKX2-1-AS1 downregulation reversed these effects, both in vitro and in vivo. Bioinformatics analysis and dual-luciferase assay showed that the microRNA miR-145-5p is a direct target of NKX2-1-AS1, and that NKX2-1-AS1 acts as a ceRNA that regulates angiogenesis in the context of GC. The mechanistic study revealed that miR-145-5p specifically targets serpin family E member 1 (SERPINE1), and that the complex NKX2-1-AS1/miR-145-5p activates VEGFR2 signaling, via SERPINE1, to promote tumor proliferation and angiogenesis. Conclusion: NKX2-1-AS1 upregulation is associated with tumor cell proliferation, increased angiogenesis, and poor prognosis in GC patients. NKX2-1-AS1 regulates SERPINE1 expression and VEGFR2 signaling by acting as a ceRNA for miR-145-5p.

scholarly journals Intermittent hypoxia induces NF-κB-dependent endothelial activation via adipocyte-derived mediators

2016 ◽  
Vol 310 (6) ◽  
pp. C446-C455 ◽  
Author(s):  
Mary Y. K. Lee ◽  
Yan Wang ◽  
Judith C. W. Mak ◽  
Mary S. M. Ip
Keyword(s):  
Endothelial Cells ◽  
Adipose Tissue ◽  
Intermittent Hypoxia ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Conditioned Media ◽  
Adipose Tissues ◽  
Nadph Oxidase 4 ◽  
Obstructive Sleep

Aberrant release of adipocytokines from adipose tissues dysregulates cardiometabolic functions. The present study hypothesizes that chronic intermittent hypoxia (IH) present in obstructive sleep apnea leads to adipose tissue dysfunction, which in turn contributes to vascular pathogenesis. The effect of IH was evaluated in adipose depots and aortic tissues in lean rats in vivo. Furthermore, the cellular and molecular mechanisms underlying pathophysiological interactions between adipocytes and endothelial cells were investigated in vitro. The in vivo results showed that IH induced upregulation of IL-6 and monocyte chemoattractant protein-1 (MCP-1) in subcutaneous and periaortic adipose tissues and downregulated phosphorylation of endothelial nitric oxide synthase [eNOS (ser1177)] in the aorta with activation of Erk and p38 MAPK. In support, cultured adipocytes demonstrated IH-induced elevations of NADPH oxidase 4, phosphorylation of Erk, NF-κBp65, and inducible NOS (iNOS) and increased expression of IL-6 and MCP-1. Likewise, endothelial EA.hy926 (EA) cells exposed to IH showed eNOS (ser1177) and intracellular cGMP reduction, whereas MCP-1 and iNOS expression were upregulated. Treatment of EA cells with conditioned media derived from IH-exposed cultured adipocytes caused nuclear translocation of NF-κBp65 and elevation of MCP-1, which were prevented by addition of neutralizing IL-6 antibodies to the conditioned media. Recombinant IL-6 in addition to IH induced further MCP-1 release and iNOS protein expression in EA cells, which were prevented by pharmacological inhibition of Erk, p38, and NF-κB. These findings suggest that IH could induce adipose tissue inflammation, which may cross talk with endothelial cells via adipocyte-derived mediators such as IL-6, and promote NF-κB-dependent endothelial dysfunction.

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