SPOP mutation induces DNA methylation via stabilizing GLP/G9a.

Area of Science:

• Oncology
• Molecular Biology
• Epigenetics

Background:

• SPOP (Speckle-type POZ protein) mutations are linked to prostate cancer (PCa) and DNA hypermethylation.
• The precise mechanisms connecting SPOP mutations to aberrant DNA methylation remain unclear.

Purpose of the Study:

• To elucidate the molecular mechanisms by which SPOP mutations drive DNA hypermethylation in PCa.
• To investigate the therapeutic potential of targeting the identified pathway in SPOP-mutated PCa.

Main Methods:

• Investigated SPOP's interaction with histone methyltransferase GLP (G9a-like protein).
• Assessed the impact of SPOP mutation on GLP/G9a stability and global DNA methylation levels.
• Performed genome-wide DNA methylome analysis and gene expression profiling.
• Evaluated the efficacy of 5-azacytidine and docetaxel in preclinical models.

Main Results:

• SPOP directly binds and promotes the degradation of GLP.
• SPOP mutations lead to GLP stabilization, G9a upregulation, and global DNA hypermethylation in PCa cells.
• Key tumor suppressor genes (e.g., FOXO3, GATA5, NDRG1) are hypermethylated and downregulated in SPOP-mutated PCa.
• 5-azacytidine reversed TSG silencing, inhibited PCa cell growth, and enhanced docetaxel efficacy.

Conclusions:

• The GLP/G9a-DNMT pathway mediates DNA hypermethylation in SPOP-mutated PCa.
• SPOP mutation status may serve as a predictive biomarker for response to DNA methylation inhibitors and taxane-based therapies in PCa.