Potent and Selective PTDSS1 Inhibitors Induce Collateral Lethality in Cancers with PTDSS2 Deletion

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Therapeutics

Background:

• Phosphatidylserine (PS) is a vital membrane phospholipid.
• PTDSS2 deletion is observed in certain cancers, but its synthetic lethality is not fully understood.
• Understanding PS synthesis pathways is crucial for developing targeted cancer therapies.

Purpose of the Study:

• To investigate the role of PTDSS1 in PS synthesis after PTDSS2 deletion.
• To identify and evaluate novel PTDSS1 inhibitors as a potential therapeutic strategy.
• To explore the concept of collateral lethality in cancers with PTDSS2 loss.

Main Methods:

• Gene deletion studies to remove PTDSS2.
• Biochemical assays to measure phosphatidylserine synthesis.
• Development and testing of small molecule PTDSS1 inhibitors.
• Cell viability assays in cancer cell lines with and without PTDSS2.

Main Results:

• PTDSS1 is essential for maintaining phosphatidylserine synthesis when PTDSS2 is absent.
• Novel PTDSS1 inhibitors effectively block PS synthesis.
• PTDSS1 inhibition leads to synthetic lethality in cancer cells lacking PTDSS2.
• This establishes a collateral lethality vulnerability in PTDSS2-deficient cancers.

Conclusions:

• PTDSS1 is a critical compensatory enzyme for PS synthesis in the absence of PTDSS2.
• Targeting PTDSS1 with novel inhibitors presents a promising therapeutic avenue for PTDSS2-deficient cancers.
• This work elucidates a novel synthetic lethality vulnerability for targeted cancer therapy.