SPOP Mutation Drives Prostate Tumorigenesis In Vivo through Coordinate Regulation of PI3K/mTOR and AR Signaling

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Recurrent point mutations in the Speckle-type POZ protein (SPOP) gene identify a specific molecular subtype of prostate cancer.
• Understanding the role of SPOP mutations in prostate cancer development is crucial for targeted therapies.

Purpose of the Study:

• To develop and characterize a mouse model that recapitulates SPOP-driven prostate tumorigenesis.
• To investigate the molecular mechanisms by which mutant SPOP contributes to prostate cancer progression.
• To identify key signaling pathways affected by SPOP mutations in prostate cancer.

Main Methods:

• Development of a conditional mouse model for inducible expression of mutant SPOP in the prostate.
• Analysis of prostate tissue phenotypes, including high-grade prostatic intraepithelial neoplasia and invasive carcinoma.
• Utilizing mouse prostate organoids to study cellular proliferation and transcriptional changes.
• Integration of data from mouse models and human prostate cancer samples.

Main Results:

• Mutant SPOP expression in the mouse prostate, particularly with Pten loss, led to aggressive neoplastic lesions and invasive carcinoma.
• Mouse prostate organoids with mutant SPOP exhibited increased proliferation and a transcriptional profile mirroring human prostate cancer.
• SPOP mutations were shown to activate both PI3K/mTOR and androgen receptor signaling pathways.
• These mutations disrupt the normal negative feedback loop between PI3K/mTOR and androgen receptor signaling.

Conclusions:

• Mutant SPOP is a driver of prostate tumorigenesis in vivo, defining a distinct molecular subclass.
• The mouse model and organoids provide valuable tools for studying SPOP-mutant prostate cancer.
• SPOP mutation-induced activation of PI3K/mTOR and androgen receptor signaling is a key mechanism in prostate cancer progression.