Identification of a novel small-molecule inhibitor of the hypoxia-inducible factor 1 pathway.

Abstract

Hypoxia-inducible factor 1 (HIF-1) is the central mediator of cellular responses to low oxygen and has recently become an important therapeutic target for solid tumor therapy. Inhibition of HIF-1 is expected to result in the attenuation of hypoxia-inducible genes, which are vital to many aspects of tumor biology, including adaptative responses for survival under anaerobic conditions. To identify small molecules inhibiting the HIF-1 pathway, we did a biological screen on a 10,000-membered natural product-like combinatorial library. The compounds of the library, which share a 2,2-dimethylbenzopyran structural motif, were tested for their ability to inhibit the hypoxic activation of an alkaline phosphatase reporter gene under the control of hypoxia-responsive elements in human glioma cells. This effort led to the discovery of 103D5R, a novel small-molecule inhibitor of HIF-1alpha. 103D5R markedly decreased HIF-1alpha protein levels induced by hypoxia or cobaltous ions in a dose- and time-dependent manner, whereas minimally affecting global cellular protein expression levels, including that of control proteins such as HIF-1beta, IkappaBalpha, and beta-actin. The inhibitory activity of 103D5R against HIF-1alpha was clearly shown under normoxia and hypoxia in cells derived from different cancer types, including glioma, prostate, and breast cancers. This inhibition prevented the activation of HIF-1 target genes under hypoxia such as vascular endothelial growth factor (VEGF) and glucose transporter-1 (Glut-1). Investigations into the molecular mechanism showed that 103D5R strongly reduced HIF-1alpha protein synthesis, whereas HIF-1alpha mRNA levels and HIF-1alpha degradation were not affected. 103D5R inhibited the phosphorylation of Akt, Erk1/2, and stress-activated protein kinase/c-jun-NH(2)-kinase, without changing the total levels of these proteins. Further studies on the mechanism of action of 103D5R will likely provide new insights into its validity/applicability for the pharmacologic targeting of HIF-1alpha for therapeutic purposes.

• Authors: Chalet Tan, Rita G de Noronha, Anthony J Roecker, Beata Pyrzynska, Fatima Khwaja, Zhaobin Zhang, Huanchun Zhang, Quincy Teng, Ainsley C Nicholson, Paraskevi Giannakakou, Wei Zhou, Jeffrey J Olson, M Manuela Pereira, K C Nicolaou, Erwin G Van Meir
• Journal: Cancer research (Cancer Res) Vol. 65 Issue 2 Pg. 605-12 (Jan 15 2005) ISSN: 0008-5472 [Print] United States
• PMID: 15695405 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• 103D5R
• Benzopyrans
• Biological Factors
• DNA-Binding Proteins
• HIF1A protein, human
• Hypoxia-Inducible Factor 1
• Hypoxia-Inducible Factor 1, alpha Subunit
• Nuclear Proteins
• RNA, Messenger
• Transcription Factors
• Vascular Endothelial Growth Factor A

Topics

• Benzopyrans (pharmacology)
• Biological Factors (pharmacology)
• Breast Neoplasms (drug therapy)
• Cell Line, Tumor
• Combinatorial Chemistry Techniques
• DNA-Binding Proteins (antagonists & inhibitors, biosynthesis, genetics, metabolism)
• Dose-Response Relationship, Drug
• Glioblastoma (drug therapy)
• Humans
• Hypoxia-Inducible Factor 1
• Hypoxia-Inducible Factor 1, alpha Subunit
• Male
• Nuclear Proteins (antagonists & inhibitors, biosynthesis, genetics, metabolism)
• Prostatic Neoplasms (drug therapy)
• RNA, Messenger (biosynthesis, genetics)
• Transcription Factors (antagonists & inhibitors, biosynthesis, genetics, metabolism)
• Transcription, Genetic (drug effects)
• Vascular Endothelial Growth Factor A (antagonists & inhibitors, biosynthesis, genetics)