Hypoxia-inducible-factor 2 alpha mediates cisplatin resistance in the lung adenocarcinoma cell line A549

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10573-10573
Author(s):  
F. Rose ◽  
B. Eul ◽  
G. Kwapiszewska ◽  
L. Marsh ◽  
F. Kamlah ◽  
...  

10573 Background: Hypoxia in solid tumors is associated with cancer progression, metastasis and resistance to chemotherapy. The hypoxia inducible factors (HIF-1a and HIF-2a) are key players in the response to hypoxia affecting angiogenesis, proliferation and apoptosis. Here we investigated the role of HIF-1a and HIF-2a in cellular resistance to cisplatin in non small lung cancer cells (A549). Results: Hypoxia reduced the efficiency of cisplatin treatment on A549 cells via enhancement of drug efflux activity. In addition, hypoxia induced the hypoxia-responsive-element (HRE) reporter gene assay, demonstrating the transcriptional activity of HIF-1a and HIF-2a. Administration of cisplatin further increased the reporter activity under both normoxic and hypoxic conditions. This correlated with the induction of HIF-2a protein expression upon cisplatin treatment in normoxia and hypoxia, whereas HIF-1a was suppressed. Additionally, cisplatin induced nuclear accumulation of HIF-2a. Suppression of HIF-2a by RNA interference potentiated the sensitivity to cisplatin treatment in hypoxic A549 cells. In vivo growth delay assay gave analogues results for subcutaneous A549 tumors treated with cisplatin and suppression of HIF-2a. In comparison, other cytostatic drugs such as doxorubicin and gemcitabine differed with respect to HIF signalling. Doxorubicin induced both HIF-1a and HIF- 2a. Cellular sensitivity to doxorubicin was increased via suppression of HIF-1a and HIF-2a. Gemcitabine appeared to act independent of HIF. The underlying mechanism of hypoxia-induced resistance was due to increased mRNA expression of drug resistance proteins such as MDR1, MRP1 and LRP. These were found to be HIF-2a but not HIF-1a dependent. Conclusion: This data identified HIF-2a as a key player in the hypoxia induced cisplatin resistance and show on the molecular level that HIF-2a is a credible target for therapeutic strategies. No significant financial relationships to disclose.

2021 ◽  
Author(s):  
Hongwei Liu ◽  
Xiujin Hu ◽  
Weihe Tan ◽  
Peng Zhou ◽  
Yanmei Liu ◽  
...  

Abstract Tumor vascular mimicry (VM) is the process of new blood vessels formed by tumor cells rather than endothelial cells. An increasing number of researches have revealed that VM process is associated with cancer progression and metastasis. miR-138-5p has been reported to act as a tumor suppressor in many cancers. However, the role and underlying mechanism of miR-138-5p in hepatocellular carcinoma (HCC) VM remain unclear. In this study, VM density was detected by CD31/periodic acid-Schiff double staining in HCC clinical specimens. We found that miR-138-5p expression correlated strongly negatively with microvessel density. Additionally, miR-138-5p mimic or inhibitor decreased or increased, respectively, tube formation capacity in HepG2 and Hep3B cells. Consistent with this, miR-138-5p repressed vessel density in vivo. Moreover, miR-138-5p targeted hypoxia-inducible factor 1α (HIF-1α) and regulated expression of HIF-1α and vascular endothelial growth factor A (VEGFA), which are established classical markers of angiogenesis. Consistent with these findings, the HIF-1α inhibitor CAY10585 effectively blocked HCC cell VM and VEGFA expression. In conclusion, miR-138-5p inhibits HepG2 and Hep3B cell VM by blocking the HIF-1α/VEGFA pathway. Therefore, miR-138-5p may serve as a useful therapeutic target for miRNA-based HCC therapy.


Tumor Biology ◽  
2021 ◽  
Vol 43 (1) ◽  
pp. 11-26
Author(s):  
Maike Busch ◽  
Natalia Miroschnikov ◽  
Jaroslaw Thomas Dankert ◽  
Marc Wiesehöfer ◽  
Klaus Metz ◽  
...  

BACKGROUND: Retinoblastoma (RB) is the most common childhood eye cancer. Chemotherapeutic drugs such as etoposide used in RB treatment often cause massive side effects and acquired drug resistances. Dysregulated genes and miRNAs have a large impact on cancer progression and development of chemotherapy resistances. OBJECTIVE: This study was designed to investigate the involvement of retinoic acid receptor alpha (RARα) in RB progression and chemoresistance as well as the impact of miR-138, a potential RARα regulating miRNA. METHODS: RARα and miR-138 expression in etoposide resistant RB cell lines and chemotherapy treated patient tumors compared to non-treated tumors was revealed by Real-Time PCR. Overexpression approaches were performed to analyze the effects of RARα on RB cell viability, apoptosis, proliferation and tumorigenesis. Besides, we addressed the effect of miR-138 overexpression on RB cell chemotherapy resistance. RESULTS: A binding between miR-138 and RARα was shown by dual luciferase reporter gene assay. The study presented revealed that RARα is downregulated in etoposide resistant RB cells, while miR-138 is endogenously upregulated. Opposing RARα and miR-138 expression levels were detectable in chemotherapy pre-treated compared to non-treated RB tumor specimen. Overexpression of RARα increases apoptosis levels and reduces tumor cell growth of aggressive etoposide resistant RB cells in vitro and in vivo. Overexpression of miR-138 in chemo-sensitive RB cell lines partly enhances cell viability after etoposide treatment. CONCLUSIONS: Our findings show that RARα acts as a tumor suppressor in retinoblastoma and is downregulated upon etoposide resistance in RB cells. Thus, RARα may contribute to the development and progression of RB chemo-resistance.


2010 ◽  
Vol 70 (2) ◽  
pp. 425-434 ◽  
Author(s):  
WR Barrionuevo ◽  
MN Fernandes ◽  
O Rocha

In order to verify the influence of chronic and acute ambient oxygen levels from egg to adult stage of the zebrafish, in vivo oxygen consumption (MO2), critical tensions of oxygen (Pcrit), heart rate (fH) and total body lactate concentration (Lc) were determined for Danio rerio (Hamilton, 1822) raised at 28 °C under normoxic (7.5 mgO2.L-1 or 80 mm.Hg-1) and hypoxic conditions (4.3 mgO2.L-1) and exposed to acute hypoxia during different developmental stages. Our findings confirmed that very early stages do not respond effectively to ambient acute hypoxia. However, after the stage corresponding to the age of 30 days, D. rerio was able to respond to acute hypoxia through effective physiological mechanisms involving aerobic and anaerobic metabolism. Such responses were more efficient for the fishes reared under hypoxia which showed that D. rerio survival capability increased during acclimation to mild hypoxia. Measurements of body mass and length showed that moderate hypoxia did not affect growth significantly until the fish reached the stage of 60 days. Moreover, a growth delay was verified for the hypoxic-reared animals. Also, the D. rerio eggs-to-larvae survival varied from 87.7 to 62.4% in animals reared under normoxia and mild hypoxia, respectively. However, the surviving animals raised under moderated hypoxia showed a better aptitude to regulate aerobic and anaerobic capacities when exposed to acute hypoxia.


2009 ◽  
Vol 424 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Jeong Hae Choi ◽  
Hyun Kook Cho ◽  
Yung Hyun Choi ◽  
JaeHun Cheong

HIF-1 (hypoxia inducible factor 1) performs a crucial role in mediating the response to hypoxia. However, other transcription factors are also capable of regulating hypoxia-induced target-gene transcription. In a previous report, we demonstrated that the transcription factor ATF-2 (activating transcription factor 2) regulates hypoxia-induced gene transcription, along with HIF-1α. In the present study, we show that the protein stability of ATF-2 is induced by hypoxia and the hypoxia-mimic CoCl2 (cobalt chloride), and that ATF-2 induction enhances HIF-1α protein stability via direct protein interaction. The knockdown of ATF-2 using small interfering RNA and translation-inhibition experiments demonstrated that ATF-2 plays a key role in the maintenance of the expression level and transcriptional activity of HIF-1α. Furthermore, we determined that ATF-2 interacts directly with HIF-1α both in vivo and in vitro and competes with the tumour suppressor protein p53 for HIF-1α binding. Collectively, these results show that protein stabilization of ATF-2 under hypoxic conditions is required for the induction of the protein stability and transactivation activity of HIF-1α for efficient hypoxia-associated gene expression.


2019 ◽  
Vol 8 (8) ◽  
pp. 1231
Author(s):  
Choi ◽  
Moon ◽  
Jung ◽  
Lim ◽  
Lee ◽  
...  

Background: The efficacy of interstitial vascular fraction (SVF) transplantation in the treatment of heart disease has been proven in a variety of in vivo studies. In a previous study, we found that bone marrow-derived mesenchymal stem cells (BM-MSCs) altered their expression of several cardiomyogenic factors under hypoxic conditions. Methods: We hypothesized that hypoxia may also induce obtained adipose-derived adherent stromal cells (ADASs) from SVFs and adipose-derived stem cells (ASCs) to differentiate into cardiomyocytes and/or cells with comparable phenotypes. We examined the differentiation markers of cell lineages in ADASs and ASCs according to time by hypoxic stress and found that only ADASs expressed cardiomyogenic markers within 24 hours under hypoxic conditions in association with the expression of hypoxia-inducible factor 1-α (HIF-1α). Results: Differentially secreted proteins in a conditioned medium (CM) from ASCs and ADASs under normoxic or hypoxic conditions were detected using an antibody assay and may be associated with a dramatic increase in the expression of cardiomyogenic markers in only ADASs. Furthermore, the cardiomyogenic factors were expressed more rapidly in ADASs than in ASCs under hypoxic conditions in association with the expression of HIF-1α, and angiogenin, fibroblast growth factor-19 (FGF-19) and/or macrophage inhibitory factor (MIF) are related. Conclusions: These results provide new insights into the applicability of ADASs preconditioned by hypoxic stress in cardiac diseases.


2019 ◽  
Vol 20 (2) ◽  
pp. 244 ◽  
Author(s):  
Kan-Yen Hsieh ◽  
Chien-Kei Wei ◽  
Chin-Chung Wu

Tissue factor (TF) expressed in cancer cells has been linked to tumor-associated thrombosis, a major cause of mortality in malignancy. Hypoxia is a common feature of solid tumors and can upregulate TF. In this study, the effect of YC-1, a putative inhibitor of hypoxia-inducible factor-1α (HIF-1α), on hypoxia-induced TF expression was investigated in human lung cancer A549 cells. YC-1 selectively prevented hypoxia-induced TF expression and procoagulant activity without affecting the basal TF levels. Surprisingly, knockdown or pharmacological inhibition of HIF-1α failed to mimic YC-1′s effect on TF expression, suggesting other mechanisms are involved. NF-κB, a transcription factor for TF, and its upstream regulator p38, were activated by hypoxia exposure. Treatment of hypoxic A549 cells with YC-1 prevented the activation of both NF-κB and p38. Inhibition of p38 suppressed hypoxia-activated NF-κB, and inhibited TF expression and activity to similar levels as treatment with an NF-κB inhibitor. Furthermore, stimulation of p38 by anisomycin reversed the effects of YC-1. Taken together, our results suggest that YC-1 prevents hypoxia-induced TF in cancer cells by inhibiting the p38/NF-κB pathway, this is distinct from the conventional anticoagulants that systemically inhibit blood coagulation and may shed new light on approaches to treat tumor-associated thrombosis.


2007 ◽  
Vol 97 (05) ◽  
pp. 774-787 ◽  
Author(s):  
Norbert Weissmann ◽  
Friedrich Grimminger ◽  
Werner Seeger ◽  
Frank Rose ◽  
Jörg Hänze

SummaryHypoxia-inducible factor (HIF) is an oxygen-dependent transcription factor that activates a diverse set of target genes, the products of which are involved in adaptive processes to hypoxia. Employing genetic manipulation of HIF expression, in-vivo and cellular studies have focused on HIF as a crucial factor affecting hypoxia-induced vascular remodeling.Vascular remodeling comprises processes which establish and improve blood vessel supply such as vasculogenesis, angiogenesis and arteriogenesis. These processes are observed during ontogenesis, tumor progression, ischemic disease or physical training. Furthermore, under hypoxic conditions, a pulmonary-specific type of vascular remodeling called pulmonary arterial remodeling occurs that is characterized by thickening of the vessel wall with a concomitant reduction in the vessel lumen area, thereby limiting blood flow.This response results in pulmonary hypertension with right ventricular hypertrophy, a lethal disease. In this review, we summarize and discuss mechanisms by which HIF interferes with the different vascular remodeling processes.


2019 ◽  
Vol 316 (3) ◽  
pp. L547-L557 ◽  
Author(s):  
Ruifeng Zhang ◽  
Hua Su ◽  
Xiuqing Ma ◽  
Xiaoling Xu ◽  
Li Liang ◽  
...  

Angiotensin-converting enzyme 2 (ACE2) protects against hypoxic pulmonary hypertension (HPH) by inhibiting the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). Under hypoxia, the hypoxia-inducible factor 1α (HIF-1α) inhibits ACE2 indirectly; however, the underlying mechanism is unclear. In the present study, we found that exposure to chronic hypoxia stimulated microRNA (miRNA) let-7b expression in rat lung via a HIF-1α-dependent pathway. Let-7b downregulated ACE2 expression by directly targeting the coding sequence of ACE2. Our in vitro and in vivo results revealed that let-7b contributed to the pathogenesis of HPH by inducing PASMCs proliferation and migration. Let-7b knockout mitigated right ventricle hypertrophy and pulmonary vessel remodeling in HPH by restoring ACE2 expression. Overall, we demonstrated that HIF-1α inhibited ACE2 expression via the HIF-1α-let-7b-ACE2 axis, which contributed to the pathogenesis of HPH by stimulating PASMCs proliferation and migration. Since let-7b knockout alleviated the development of HPH, let-7b may serve as a potential clinical target for the treatment of HPH.


2015 ◽  
Vol 37 (5) ◽  
pp. 1956-1966 ◽  
Author(s):  
Shiping Liu ◽  
Peng Feng

Background/Aims: Increasing evidence has shown that miR-203 plays important role in human cancer progression. However, little is known about the function of miR-203 in osteosarcoma (OS). Methods: The expression of miR-203 in OS tissues and cell lines were examined by qRT-PCR. The biological role of miR-20 in OS cell proliferation was examined in vitro and in vivo. The targets of miR-203 were identified by a luciferase reporter gene assay. Results: miR-203 was down regulated in OS tissues and cell lines; decreased miR-203 was associated with a poor overall survival in OS patients. Restoration of miR-203 expression reduced cell growth in vitro and suppressed tumorigenicity in vivo. In contrast, inhibition of miR-203 stimulated OS cell growth both in vitro and in vivo. In addition, TANK binding kinase 1 (TBK1) was identified as a direct target of miR-203; overexpression of TBK1 partly reversed the suppressive effects of miR-203. Furthermore, TBK1 was found up-regulated and inversely correlated with miR-203 in OS tissues. Conclusion: Taken together, these findings suggest that miR-203 acts as a tumor suppressor via regulation of TBK1 expression in OS progression, and miR-203 may be a promising therapeutic target for OS.


2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Min Yang ◽  
Nan Jiang ◽  
Qi-wei Cao ◽  
Qing Sun

Abstract Gastric cancer is the most common digestive malignant tumor worldwild. EDD1 was reported to be frequently amplified in several tumors and played an important role in the tumorigenesis process. However, the biological role and potential mechanism of EDD1 in gastric cancer remains poorly understood. In this study, we are aim to investigate the effect of EDD1 on gastric cancer progression and to explore the underlying mechanism. The results showed the significant up-regulation of EDD1 in -gastric cancer cell tissues and lines. The expression level of EDD1 was also positively associated with advanced clinical stages and predicted poor overall patient survival and poor disease-free patient survival. Besides, EDD1 knockdown markedly inhibited cell viability, colony formation, and suppressed tumor growth. Opposite results were obtained in gastric cancer cells with EDD1 overexpression. EDD1 knockdown was also found to induce gastric cancer cells apoptosis. Further investigation indicated that the oncogenic role of EDD1 in regulating gastric cancer cells growth and apoptosis was related to its PABC domain and directly through targeting miR-22, which was significantly down-regulated in gastric cancer tissues. Totally, our study suggests that EDD1 plays an oncogenic role in gastric cancer and may be a potential therapeutic target for gastric cancer.


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