Caspase-2 protects against ferroptotic cell death

Area of Science:

• Cellular Biology
• Molecular Oncology
• Biochemistry

Background:

• Caspase-2 is a conserved caspase involved in cellular stress responses.
• Ferroptosis, a regulated cell death, is suppressed by antioxidant pathways like glutathione peroxidase 4 (GPX4).

Purpose of the Study:

• To investigate the role of caspase-2 in regulating ferroptosis.
• To determine if caspase-2 influences ferroptosis in cancer cells, particularly those with mutant p53.

Main Methods:

• Depletion of caspase-2 using genetic techniques.
• Analysis of stress response gene expression (SESN2, HMOX1, SLC7A11).
• BioID proteomics screen to identify interacting proteins.
• Assessment of GPX4 levels and chaperone-mediated autophagic degradation.

Main Results:

• Caspase-2 depletion downregulates key stress response genes and sensitizes mutant-p53 cancer cells to ferroptosis.
• Caspase-2's protective role against ferroptosis does not require its catalytic activity.
• Caspase-2 interacts with proteins involved in cellular stress responses, including chaperones.
• Caspase-2 inhibits the autophagic degradation of GPX4, thereby promoting cancer cell survival.

Conclusions:

• Caspase-2 acts as a novel negative regulator of ferroptosis in mutant-p53 cancer cells.
• This function is mediated through non-proteolytic interactions and regulation of GPX4 stability.
• Caspase-2 represents a potential therapeutic target for exploiting ferroptosis in cancer treatment.