Reversing-or Rewiring-Lineage Plasticity? Lessons from EZH2 Loss in Prostate Cancer

Area of Science:

• Oncology
• Molecular Biology
• Epigenetics

Background:

• Enhancer of zeste homolog 2 (EZH2) inhibition is explored to reverse prostate cancer lineage plasticity (LP) and resensitize tumors to androgen receptor (AR) inhibition.
• Prostate cancer progression involves a transition toward a neuroendocrine (NE) phenotype, a process influenced by EZH2.

Purpose of the Study:

• To investigate the mechanistic role of EZH2 in prostate cancer progression and the transition to a neuroendocrine phenotype.
• To elucidate how EZH2 loss impacts lineage plasticity and transcription factor programs.

Main Methods:

• Utilized a genetically engineered mouse model recapitulating prostate cancer progression to a NE phenotype.
• Performed genetic deletion of Ezh2 to assess its effects on LP and NE differentiation.
• Analyzed transcription factor (TF) activation, chromatin-binding landscape of AR, and genomic site association.

Main Results:

• Genetic deletion of Ezh2 did not reverse LP but unexpectedly promoted NE differentiation.
• Loss of EZH2 activated KLF transcription factor family members, contributing to transcriptional diversification.
• EZH2 deletion altered AR chromatin binding, redirecting it to KLF-associated genomic sites, thus reshaping the AR cistrome.

Conclusions:

• EZH2 loss in prostate cancer does not simply reverse LP but rather rewires transcriptional networks and alters the AR cistrome.
• These findings refine the understanding of EZH2 function and have implications for the clinical deployment of EZH2 inhibitors in metastatic prostate cancer.
• Further research is needed to define optimal strategies for using EZH2 inhibition to modulate tumor lineage dynamics.