Inhibition of hypoxia inducible factor by phenethyl isothiocyanate

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Phenethyl isothiocyanate (PEITC) is a natural compound with demonstrated anti-cancer properties.
• PEITC's ability to inhibit angiogenesis is known, but the underlying molecular mechanisms remain unclear.
• Hypoxia-inducible factor (HIF) is a key transcription factor regulating pro-angiogenic factors and is implicated in cancer progression.

Purpose of the Study:

• To investigate the molecular mechanisms by which PEITC exerts its anti-angiogenic and anti-cancer effects.
• To determine if PEITC affects the activity or expression of hypoxia-inducible factor (HIF).

Main Methods:

• Cells were exposed to hypoxia or cobalt chloride (hypoxia mimetic) with or without PEITC treatment.
• HIF-dependent reporter constructs, HIF1alpha protein accumulation, and HIF target gene expression (CAIX, GLUT1, BNIP3, VEGF-A) were analyzed.
• Mechanisms of HIF1alpha regulation, including prolyl hydroxylases, Von-Hippel-Landau protein, proteasome activity, RNA levels, and translation regulator 4E-BP1 phosphorylation, were assessed.

Main Results:

• PEITC effectively inhibited HIF-dependent reporter construct activation under hypoxic conditions.
• PEITC treatment led to decreased accumulation of HIF1alpha protein and reduced expression of HIF target genes.
• PEITC's inhibitory effect on HIF activity was independent of canonical HIF regulation pathways (prolyl hydroxylases, VHL, proteasome).
• PEITC appeared to inhibit HIF activity by suppressing HIF1alpha translation, evidenced by unchanged HIF1alpha RNA levels and decreased 4E-BP1 phosphorylation.

Conclusions:

• PEITC is a potent inhibitor of hypoxia-inducible factor (HIF) activity.
• PEITC inhibits HIF activation by interfering with HIF1alpha translation.
• The inhibition of HIF activity by PEITC may contribute to its observed anti-angiogenic and anti-cancer effects.