Anthracyclines, small-molecule inhibitors of hypoxia-inducible factor-1 alpha activation

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Hypoxia-Inducible Factor-1 (HIF-1) is a key regulator of cellular response to low oxygen.
• HIF-1 is a significant therapeutic target for treating solid tumors.
• Developing small molecule inhibitors of HIF-1 transcriptional activation is crucial for cancer therapy.

Purpose of the Study:

• To identify novel small molecule inhibitors of HIF-1 transcriptional activation.
• To screen a library of microbial broths for compounds targeting HIF-1.
• To evaluate the anti-angiogenic potential of identified compounds.

Main Methods:

• Established a high-throughput assay using mammalian cells with a HIF-1 binding site-luciferase reporter construct.
• Screened 5000 cultured microbial broths.
• Assessed the effect of compounds on hypoxia-induced reporter activity and Vascular Endothelial Growth Factor (VEGF) protein levels in HepG2 cells.

Main Results:

• Cinerubin (1-hydroxy aclacinomycin B) significantly inhibited HIF-1 reporter activity under hypoxic conditions.
• Aclarubicin also inhibited HIF-1 transcriptional activity, while doxorubicin and daunorubicin did not.
• Cinerubin and aclarubicin suppressed hypoxic induction of VEGF protein, indicating anti-angiogenic properties.

Conclusions:

• Certain anthracyclines, specifically cinerubin and aclarubicin, can inhibit HIF-1 transcriptional activity.
• These compounds demonstrate potential as angiogenesis inhibitors for solid tumor therapy.
• The study identified novel HIF-1 inhibitors from microbial sources.