Rapid degradation of hypoxia-inducible factor-1alpha by KRH102053, a new activator of prolyl hydroxylase 2.
OBJECTIVE
Hypoxia-inducible factor (HIF) is a transcription factor induced by hypoxia and degraded by ubiquitin-dependent proteasomes in normoxic conditions. Under hypoxic conditions, hydroxylation of HIF-1alpha subunit by prolyl hydroxylase (PHD) is suppressed, thus leading to increased levels of HIF. Although PHD2 plays a key role in regulating the levels of HIF, chemical activators of PHD2 are relatively unknown. The aim of this study was to identify small molecule activators of PHD2 that could be used, eventually, to suppress the level of HIF-1alpha.


METHODS
By using the overproduced PHD2 as a target, a molecular library consisting of more than 600 small molecules with a benzopyran structure was screened with an HPLC assay method.


RESULTS
We found a potent activator of PHD2, KRH102053 (2-amino-4-methylsulphanyl-butylic acid-4-methoxy-6-(4-methoxy-benzylamino)-2,2-dimethyl-chroman-3-yl ester). The effects of KRH102053 on controlling HIF were studied in human HOS osteosarcoma, rat PC12 phaeochromocytoma and human HepG2 hepatoma cells. Under our experimental conditions, KRH102053 decreased the protein level of HIF-1alpha and the mRNA levels of HIF-regulated downstream target genes, such as vascular endothelial growth factor, aldolase A, enolase 1 and monocarboxylate transporter 4. Consistent with these results, KRH102053 also inhibited the rates of HIF-related migration and invasion of HOS cells as well as the degree of tube formation in human umbilical vein endothelium cells.


CONCLUSIONS
These results suggest that KRH102053 and its structural analogues have the potential for use as therapeutic agents against various diseases associated with HIF.
Choi
H J
HJ
Department of Dental Pharmacology, School of Dentistry, Chonbuk National University, Jeon-Ju, Republic of Korea.
Song
B-J
BJ
Gong
Y-D
YD
Gwak
W J
WJ
Soh
Y
Y
D000613:Aminobutyrates / Q000494:pharmacology*; D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology*; D017930:Genes, Reporter; D005947:Glucose / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D047468:Immunoprecipitation; D008156:Luciferases / Q000235:genetics; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D014162:Transfection
C530086:2-amino-4-methylsulfanylbutyric acid 4-methoxy-6-(4-methoxybenzylamino)-2,2-dimethylchroman-3-yl ester; D000613:Aminobutyrates; D020533:Angiogenesis Inhibitors; D001578:Benzopyrans; D020536:Enzyme Activators; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D013778:Tetrazolium Salts; D013844:Thiazoles; D008156:Luciferases; D011393:Procollagen-Proline Dioxygenase; C022616:thiazolyl blue; D005947:Glucose