Discovery and functional characterization of a neomorphic PTEN mutation

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Identifying driver genetic lesions in cancer patients is challenging.
• Translating genomic findings into clinical strategies requires further research.
• The phosphatase and tensin homolog (PTEN) tumor suppressor is frequently altered in cancer.

Purpose of the Study:

• To identify and functionally characterize novel oncogenic activity from a PTEN point mutation in prostate cancer.
• To investigate the mechanism of PTEN gain-of-function and its impact on cancer hallmarks.
• To explore therapeutic strategies targeting this PTEN dysfunction.

Main Methods:

• Whole genome sequencing of prostate cancer tumors.
• Computational analysis to predict oncogenic activity.
• In vitro cellular assays for functional validation.
• Assessment of PI3K inhibitors for therapeutic potential.

Main Results:

• A specific PTEN point mutation (p.A126G) was identified, conferring enzymatic gain-of-function.
• This mutation shifted PTEN activity from PI 3-phosphatase to PI 5-phosphatase.
• Gain-of-function PTEN altered phosphoinositide levels, hyperactivated the PI3K/Akt pathway, and increased cell migration.
• These oncogenic effects were mitigated by PI3K inhibitors.

Conclusions:

• Mutationally altered PTEN can actively drive cancer progression through gain-of-function mechanisms.
• This represents a new paradigm in PTEN cancer biology.
• Targeting PI3K offers a potential clinical strategy for patients with this PTEN mutation, translating genomic data into therapy.