Activated pp60c-Src leads to elevated hypoxia-inducible factor (HIF)-1alpha expression under normoxia

Area of Science:

• Molecular Biology
• Cancer Research
• Cellular Metabolism

Background:

• Hypoxia-inducible factor (HIF)-1 regulates key cellular processes like glycolysis and angiogenesis.
• The Warburg effect, or aerobic glycolysis, is a hallmark of cancer cells but its mechanism remains unclear.
• HIF-1alpha accumulation in normoxic tumor cells contributes to aerobic glycolysis.

Purpose of the Study:

• To investigate the mechanism by which Hypoxia-inducible factor (HIF)-1alpha accumulates in normoxic tumor cells.
• To determine the role of pp60(c-Src) (Src) in regulating HIF-1alpha levels and the Warburg effect.

Main Methods:

• Utilized transformed cells expressing constitutively active pp60(c-Src) (Src).
• Assessed HIF-1alpha protein levels under normoxic conditions.
• Investigated protein synthesis and degradation rates of HIF-1alpha.
• Analyzed the role of cap-dependent translation.

Main Results:

• Transformed cells expressing Src exhibited HIF-1alpha protein accumulation under normoxia.
• This accumulation led to the expression of multiple HIF-1alpha target genes.
• The increase in HIF-1alpha was attributed to enhanced protein synthesis, not reduced degradation.
• Src-induced protein synthesis resulted from increased cap-dependent translation.

Conclusions:

• Constitutively active Src signaling promotes HIF-1alpha protein synthesis under normoxia.
• This mechanism contributes to the Warburg effect in cancer cells.
• Targeting Src-mediated translation may offer a strategy to inhibit cancer metabolism.