Tumor suppressor Par-4 activates autophagy-dependent ferroptosis

Area of Science:

• Cell Biology
• Oncology
• Biochemistry

Background:

• Ferroptosis is an iron-dependent cell death marked by lipid peroxidation.
• Its regulation by autophagy is increasingly recognized, but molecular mechanisms remain unclear.
• Understanding ferroptosis regulation is key for developing novel cancer therapies.

Purpose of the Study:

• To identify novel regulators of ferroptosis.
• To elucidate the molecular mechanisms linking Par-4 to ferroptosis.
• To explore the therapeutic potential of targeting Par-4 in cancer.

Main Methods:

• Unbiased RNA-sequencing screening to identify ferroptosis-associated genes.
• Genetic manipulation (depletion and overexpression) of Par-4.
• Analysis of autophagic pathways, specifically ferritinophagy.
• Assessment of reactive oxygen species (ROS) production.
• In vivo studies using mouse xenograft models.

Main Results:

• Par-4 (PAWR) is activated during ferroptosis and acts as a tumor suppressor.
• Par-4 depletion inhibits ferroptosis; Par-4 overexpression sensitizes cells to ferroptosis.
• Par-4 promotes ferritinophagy via NCOA4, increasing labile iron and lipid peroxidation.
• Par-4 activation correlates with ROS production, essential for ferroptosis.
• Par-4 knockdown inhibits ferroptosis-mediated tumor suppression in vivo.

Conclusions:

• Par-4 plays a critical role in regulating ferroptosis through the NCOA4-mediated ferritinophagy pathway.
• Targeting Par-4 and its associated pathway offers a promising strategy for cancer therapy.