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Selective covalent targeting of GPX4 using masked nitrile-oxide electrophiles
John K Eaton1, Laura Furst1, Richard A Ruberto1
1Broad Institute, Cambridge, MA, USA.
Abstract:
We recently described glutathione peroxidase 4 (GPX4) as a promising target for killing therapy-resistant cancer cells via ferroptosis. The onset of therapy resistance by multiple types of treatment results in a stable cell state marked by high levels of polyunsaturated lipids and an acquired dependency on GPX4. Unfortunately, all existing inhibitors of GPX4 act covalently via a reactive alkyl chloride moiety that confers poor selectivity and pharmacokinetic properties. Here, we report our discovery that masked nitrile-oxide electrophiles, which have not been explored previously as covalent cellular probes, undergo remarkable chemical transformations in cells and provide an effective strategy for selective targeting of GPX4. The new GPX4-inhibiting compounds we describe exhibit unexpected proteome-wide selectivity and, in some instances, vastly improved physiochemical and pharmacokinetic properties compared to existing chloroacetamide-based GPX4 inhibitors. These features make them superior tool compounds for biological interrogation of ferroptosis and constitute starting points for development of improved inhibitors of GPX4.
Insights
Researchers discovered novel compounds targeting glutathione peroxidase 4 (GPX4) to combat therapy-resistant cancers via ferroptosis. These new inhibitors offer improved selectivity and properties for cancer cell killing.
Area of Science:
- Biochemistry
- Chemical Biology
- Oncology
Background:
- Glutathione peroxidase 4 (GPX4) is a key target for inducing ferroptosis in therapy-resistant cancers.
- Cancer cells developing resistance often exhibit high polyunsaturated lipids and depend on GPX4.
- Existing GPX4 inhibitors have limitations in selectivity and pharmacokinetic properties due to their chemical structure.
Purpose of the Study:
- To discover novel covalent cellular probes for selective GPX4 targeting.
- To develop improved inhibitors of GPX4 with enhanced selectivity and pharmacokinetic profiles.
- To explore masked nitrile-oxide electrophiles as a new class of chemical probes.
Main Methods:
- Synthesis and chemical characterization of novel masked nitrile-oxide electrophiles.
- Evaluation of chemical transformations and cellular activity of the new probes.
- Assessment of proteome-wide selectivity and pharmacokinetic properties of the inhibitors.
- Comparison with existing chloroacetamide-based GPX4 inhibitors.
Main Results:
- Masked nitrile-oxide electrophiles undergo effective chemical transformations within cells.
- The new compounds selectively target GPX4, inducing ferroptosis.
- These novel inhibitors demonstrate unexpected proteome-wide selectivity.
- Some compounds exhibit significantly improved physiochemical and pharmacokinetic properties compared to current inhibitors.
Conclusions:
- Masked nitrile-oxide electrophiles represent a promising new strategy for selective GPX4 inhibition.
- The developed compounds serve as superior tools for studying ferroptosis.
- These findings provide a foundation for developing next-generation GPX4 inhibitors for cancer therapy.
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