<scp>HIF</scp>‐1 at the crossroads of hypoxia, inflammation, and cancer

Balamurugan, Krishnaswamy

doi:10.1002/ijc.29519

Cited by 446 publications

(358 citation statements)

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“…This observation is similar to the phenotype previously described in mice with in vivo overexpression of HIF1α in hepatocytes (HIF1dPA) 14,41 . Here we found that reduction of MIR122 in hepatocytes with chronic alcohol (MIR122-TuD+Et), resulted in a dramatic increase in hepatic injury, greater than alcohol or MIR122 reduction alone (Fig.…”

Section: Discussionsupporting

confidence: 90%

MicroRNA 122, Regulated by GRLH2, Protects Livers of Mice and Patients From Ethanol-Induced Liver Disease

et al. 2018

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Background & Aims Chronic, excessive alcohol consumption leads to alcoholic liver disease (ALD) characterized by steatosis, inflammation, and eventually cirrhosis. The hepatocyte specific microRNA 122 (MIR122) regulates hepatocyte differentiation and metabolism. We investigated whether an alcohol-induced decrease in level of MIR122 contributes to development of ALD. Methods We obtained liver samples from 12 patients with ALD and cirrhosis and 9 healthy individuals (controls) and analyzed them by histology and immunohistochemistry. C57Bl/6 mice were placed on a Lieber-DeCarli liquid diet, in which they were fed ethanol for 8 weeks, as a model of ALD, or a control diet. These mice were also given injections of CCl4, to increase liver fibrosis, for 8 weeks. On day 28, mice with ethanol-induced liver disease and advanced fibrosis, and controls, were given injections of recombinant adeno-associated virus 8 vector that expressed the primary miR-122 transcript (pri-MIR122, to overexpress MIR122 in hepatocytes) or vector (control). Two weeks before ethanol feeding, some mice were given injections of a vector that expressed an anti-MIR122, to knock down its expression. Serum and liver tissues were collected; hepatocytes and liver mononuclear cells were analyzed by histology, immunoblots, and confocal microscopy. We performed in silico analyses to identify targets of MIR122 and chromatin immunoprecipitation quantitative PCR analyses in Huh-7 cells. Results Levels of MIR122 were decreased in liver samples from patients with ALD and mice on the Lieber-DeCarli diet, compared with controls. Transgenic expression of MIR122 in hepatocytes of mice with ethanol-induced liver disease and advanced fibrosis significantly reduced serum levels of alanine aminotransferase (ALT) and liver steatosis and fibrosis, compared to mice given injections of the control vector. Ethanol feeding reduced expression of pri-MIR122 by increasing expression of the spliced form of the transcription factor grainyhead like transcription factor 2 (GRHL2) in livers tissues from mice. Levels of GRHL2 were also increased in liver tissues from patients with ALD, compared with controls; increases correlated with decreases in levels of MIR122 in human liver. Mice given injections of the anti-MIR122 before ethanol feeding had increased steatosis, inflammation, and serum levels of ALT compared to mice given a control vector. Levels of hypoxia inducible factor 1 alpha (HIF1A) mRNA, a target of MIR122, were increased in liver tissues from patients and mice with ALD, compared with controls. Mice with hepatocyte-specific disruption of Hif1a developed less-severe liver injury following administration of ethanol, injection of anti-MIR122, or both. Conclusions Levels of MIR122 decrease in livers from patients with ALD and mice with ethanol-induced liver disease, compared with controls. Transcription of MIR122 is inhibited by GRHL2, which is increased in livers of mice and patients with ALD. Expression of an anti-MIR122 worsened the severity of liver damage followin...

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Section: Discussionsupporting

confidence: 90%

MicroRNA 122, Regulated by GRLH2, Protects Livers of Mice and Patients From Ethanol-Induced Liver Disease

et al. 2018

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“…The high expression of HIF-1α was reported to correlate with tumor metastasis and poor clinical outcomes (13). Research has demonstrated that hypoxia induced the expression of HIF-1α to activate the process of EMT (25). A variety of biomarkers have been used to demonstrate EMT, such as epithelial markers (E-cadherin and cytokeratin) and mesenchymal markers [N-cadherin, vimentin, fibronectin and α smooth muscle actin (α-SMA)] (26).…”

Section: Discussionmentioning

confidence: 99%

Hypoxia-inducible factor 1α participates in hypoxia-induced epithelial-mesenchymal transition via response gene to complement 32

Zhu

Zhao

2017

Experimental and Therapeutic Medicine

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Abstract. The aim of the present study was to explore the function of response gene to complement 32 (RGC-32) in hypoxia-induced epithelial-mesenchymal transition (EMT) in pancreatic cancer. Three kinds of hypoxia-inducible factor 1α (HIF-1α) small interfering (si)RNA were synthesized and the different effects on the expression of HIF-1α were detected by western blotting. In human pancreatic cancer BxPC-3 cells, HIF-1α levels were diminished using siRNA transfection or HIF-1α inhibitor pretreatment, and the expression levels of RGC-32 and EMT-associated proteins were analyzed using reverse transcription-quantitative polymerase chain reaction and western blotting. Subsequently, the protein levels of epithelial marker, E-cadherin, and mesenchymal marker, vimentin, were determined by western blotting. Results demonstrated that HIF-1α-Homo-488 siRNA and HIF-1α-Homo-1216 siRNA diminished the protein level of HIF-1α. Compared with normoxia, hypoxia induced the levels of HIF-1α, RGC-32, N-cadherin and vimentin, but suppressed the expression of E-cadherin and cytokeratins. The inhibition of HIF-1α by HIF-1α-Homo-1216 siRNA transfection or HIF-1α inhibitor repressed hypoxia-induced HIF-1α, RGC-32, N-cadherin and vimentin, but increased the expression of E-cadherin and cytokeratins. When RGC-32 was knocked down, hypoxia-induced vimentin was suppressed; however, hypoxia-suppressed N-cadherin was released. In conclusion, the present results demonstrated that hypoxia induced the expression of HIF-1α to activate the levels of RGC-32, in turn to regulate the expression EMT-associated proteins for EMT. These findings revealed the function of RGC-32 in hypoxia-induced EMT and may have identified a novel link between HIF-1α and EMT for pancreatic cancer therapy. IntroductionPancreatic cancer is a highly lethal human gastrointestinal cancer (1). Although increasing methods are being applied for pancreatic cancer treatment, such as surgical resection and radiotherapy, the 5-year relative survival rate remains very dismal. A potential reason for the failure of the classical therapeutic approach may be explained by its high metastatic potential (2). Thus, it is critical to reveal the metastasis mechanism of pancreatic cancer. Epithelial-mesenchymal transition (EMT), the conversion from an epithelial to a mesenchymal phenotype, is a vital process for cancer invasion to surrounding tissues or metastasis to other organs (3). During the process of EMT, typical morphological changes occur, such as cell invasion and motility (4). The molecular indicators for EMT are the decrease of epithelial markers, such as E-cadherin, and the increase in the levels of mesenchymal markers, such as N-cadherin and vimentin (5). Significant efforts are required to investigate the mechanism of EMT for cancer control and the improvement of cure rate.Response gene to complement 32 (RGC-32), first identified in 1998, is induced by complement and involved in cell cycle activation (6). RGC-32 is comprehensively expressed in the placenta, skeletal muscle, kidney, ...

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“…Hypoxia-inducible factor-1 (HIF-1) was confirmed to be the critical response factor to hypoxia stress and was upregulated by hypoxia [25]. Hence, we investigated whether HIF-1 plays a role in enhancing the resistance of hypoxia MSCs to hypoxia stress.…”

Section: Resultsmentioning

confidence: 99%

Hypoxia-Induced Mesenchymal Stromal Cells Exhibit an Enhanced Therapeutic Effect on Radiation-Induced Lung Injury in Mice due to an Increased Proliferation Potential and Enhanced Antioxidant Ability

Zhu

et al. 2017

Cell Physiol Biochem

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Background/Aims: Radiation therapy is an important treatment for thoracic cancer; however, side effects accompanied with radiotherapy lead to limited tumor control and a decline in patient quality of life. Among these side effects, radiation-induced lung injury (RILI) is the most serious and common. Hence, an effective remedy for RILI is needed. Mesenchymal stromal cells (MSCs) are multipotent adult stem cells that have been demonstrated to be an effective treatment in some disease caused by tissue damage. However, unlike other injuries, RILI received limited therapeutic effects from implanted MSCs due to local hypoxia and extensive reactive oxygen species (ROS) in irradiated lungs. Since the poor survival of MSCs is primarily due to hypoxia and ROS generation, we hypothesize that persistent and adaptive hypoxia treatment induces enhanced resistance to hypoxic stress in implanted MSC. The aim of this study is to investigate whether persistent and adaptive hypoxia treatment of bmMSCs prior to their transplantation in injured mice enhanced survival and improved curative effects in RILI. Methods: Primary bmMSCs were obtained from the marrow of six-week-old male C57BL6/J mice and were cultured either under normoxic conditions (21% O₂) or hypoxic conditions (2.5% O₂). Mice were injected with normoxia/hypoxia MSCs after thoracic irradiation (20 Gy). The therapeutic effects of MSCs on RILI were assessed by pathological examinations that included H&E staining, Masson staining and α-SMA staining; meanwhile, inflammatory factors were measured using an ELISA. The morphology of MSCs in vitro was recorded using a microscope and identified by flow cytometry, cell viability was measured using the CCK-8 assay, the potential for proliferation was detected by the EdU assay, and ROS levels were measured using a ROS fluorogenic probe. In addition, HIF-1α and several survival pathway proteins (Akt, p-Akt, Caspase-3) were also detected by western blotting. Results: Implanted MSCs alleviated both early radiation-induced pneumonia and late pulmonary fibrosis. However, hypoxia MSCs displayed a more pronounced therapeutic effect compared to normoxia MSCs. Compared to normoxia MSCs, the hypoxia MSCs demonstrated greater cell viability, an enhanced proliferation potential, decreased ROS levels and increased resistance to hypoxia and ROS stress. In addition, hypoxia MSCs achieved higher activation levels of HIF-1α and Akt, and HIF-1α played a critical role in the development of resistance. Conclusion: Hypoxia enhances the therapeutic effect of mesenchymal stromal cells on radiation-induced lung injury by promoting MSC proliferation and improving their antioxidant ability, mediated by HIF-1α.

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HIF‐1 at the crossroads of hypoxia, inflammation, and cancer

Cited by 446 publications

References 153 publications

MicroRNA 122, Regulated by GRLH2, Protects Livers of Mice and Patients From Ethanol-Induced Liver Disease

MicroRNA 122, Regulated by GRLH2, Protects Livers of Mice and Patients From Ethanol-Induced Liver Disease

Hypoxia-inducible factor 1α participates in hypoxia-induced epithelial-mesenchymal transition via response gene to complement 32

Hypoxia-Induced Mesenchymal Stromal Cells Exhibit an Enhanced Therapeutic Effect on Radiation-Induced Lung Injury in Mice due to an Increased Proliferation Potential and Enhanced Antioxidant Ability

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