Precision Ferroptosis Amplification via SLC7A11-Directed Proteasomal Degradation for Enhanced Cancer Therapy

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Ferroptosis is an iron-dependent cell death pathway.
• Glutathione peroxidase 4 (GPX4) limits ferroptosis efficacy through its antioxidant activity.
• Targeting GPX4 is a strategy to enhance ferroptosis in cancer therapy.

Purpose of the Study:

• To develop SLC7A11-targeting proteolysis targeting chimeras (PROTACs) to deplete GPX4.
• To enhance oxidative stress and induce ferroptosis in cancer cells.
• To evaluate the antitumor efficacy of the developed PROTAC.

Main Methods:

• Design and synthesis of a bifunctional PROTAC (dSLC7A11) by conjugating a SLC7A11 inhibitor (sulfasalazine) to a CRBN ligand (pomalidomide).
• Assessment of ubiquitin-mediated degradation of SLC7A11 by the PROTAC.
• Evaluation of System Xc- inactivation, GPX4 depletion, and oxidative stress amplification in cancer cells.
• In vivo studies to determine the antitumor efficacy of dSLC7A11.

Main Results:

• The designed PROTAC, dSLC7A11, effectively induced ubiquitin-mediated degradation of SLC7A11.
• dSLC7A11 inactivated the cystine/glutamate antiporter (System Xc-), leading to GPX4 depletion.
• This resulted in amplified oxidative stress and potent ferroptosis induction in cancer cells.
• In vivo, dSLC7A11 demonstrated superior antitumor efficacy, suppressing tumor growth by over 65% compared to sulfasalazine alone.

Conclusions:

• A novel SLC7A11-targeting PROTAC was developed for potent ferroptosis induction.
• This PROTAC effectively disrupts cellular antioxidant defense systems by depleting GPX4.
• The findings establish a promising PROTAC-based therapeutic approach for cancer treatment.