Vitamin C decreases VEGF expression levels via hypoxia-inducible factor-1α dependent and independent pathways in lens epithelial cells

Autor: Feng Wang, Yi Zhang, Jianming Wang, Lin Zhao, Lijun Wang, Miao Yu
Jazyk: angličtina
Rok vydání: 2020
Předmět:
0301 basic medicine
posterior capsular opacification
Vascular Endothelial Growth Factor A
Cancer Research
proline hydroxylation
vitamin C
Down-Regulation
Ascorbic Acid
prolyl hydroxylase protein 2
Biochemistry
Cell Line
03 medical and health sciences
chemistry.chemical_compound
0302 clinical medicine
Lens
Crystalline
Genetics
Humans
Molecular Biology
Protein kinase B
Cell Proliferation
Gene knockdown
Oncogene
vascular endothelial growth factor
hypoxia-inducible factor-1α
Cell growth
AKT
Epithelial Cells
Transfection
Articles
Vitamins
Capsule Opacification
Hypoxia-Inducible Factor 1
alpha Subunit
Molecular biology
Vascular endothelial growth factor
030104 developmental biology
Oncology
chemistry
Hypoxia-inducible factors
Apoptosis
030220 oncology & carcinogenesis
Molecular Medicine
Signal Transduction
Zdroj: Molecular Medicine Reports
ISSN: 1791-3004
1791-2997
Popis: Posterior capsular opacification (PCO) is the main complication following cataract surgery. The proliferation of the residual lens epithelial cells (LECs) serves an important role in PCO formation. The authors' previous study revealed that vitamin C inhibited the proliferation of human LECs by increasing the rapid degradation of hypoxia-inducible factor-1 (HIF-1α), and hence inhibited the expression of vascular endothelial growth factor (VEGF). The present study aimed to further investigate the mechanisms underlying the effects of vitamin C on the expression levels of VEGF. The present study demonstrated that the HIF-1 inhibitor BAY 87–2243 significantly inhibited the cell proliferation and the expression levels of VEGF in LECs through the use of colony formation, western blotting and ELISA assays. Moreover, it was revealed that vitamin C could further inhibit the cell proliferation and the expression levels of VEGF in LECs following the cotreatment with the HIF-1 inhibitor. The proline hydroxylation of HIF-1α by prolyl hydroxylases (PHDs) was previously discovered to be responsible for the rapid degradation of HIF-1α. Thus, the present study subsequently used three PHD inhibitors to investigate their effects on the expression levels of VEGF; it was found that the PHD2 specific inhibitor increased the expression levels of VEGF to the greatest extent. Moreover, the genetic knockdown of PHD2 by lentiviral transfection also significantly increased the expression levels of VEGF, whereas the PHD2 specific inhibitor did not alter the expression levels of VEGF in the PHD2 knockdown LECs. AKT kinase activity is an important mediator known to upregulate VEGF expression. Using an immunoprecipitation assay to isolate endogenous AKT, it was demonstrated that AKT was prolyl hydroxylated by PHD2, which inhibited its activity. It was also revealed that vitamin C enhanced the proline-hydroxylation and inhibited the activity of AKT. Furthermore, an AKT inhibitor increased the effects of vitamin C on the expression levels of VEGF. However, the AKT inhibitor did not affect the expression levels of glucose transporter 1, which is a HIF-1α target gene. In conclusion, the findings of the present study suggested that vitamin C may inhibit the expression levels of VEGF via HIF-1α-dependent and AKT-dependent pathways in LECs.
Databáze: OpenAIRE
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