Polycomb repressive complex's evolutionary conserved function: the role of EZH2 status and cellular background

Area of Science:

• Epigenetics
• Molecular Biology
• Cancer Research

Background:

• Polycomb group (PcG) proteins, assembled into Polycomb Repressive Complexes (PRCs), epigenetically control gene activity.
• The PRC2 complex, containing embryonic ectoderm development (EED), suppressor of zeste 12 (SUZ12), and enhancer of zeste homolog 2 (EZH2), is abundant in proliferative and cancer cells.
• PRC2 establishes a repressive methylation mark on histone 3 (H3K27me3), which can promote tumor development by silencing tumor suppressor genes.

Purpose of the Study:

• To provide a critical overview of the evolutionary importance of PRC.
• To discuss EZH2 functioning within PRC, including its non-histone interactions.
• To review mutational studies on EZH2 and its relationship with H3K27me3 in cancer.

Main Methods:

• Literature review of evolutionary aspects of PRC.
• Analysis of EZH2's role in various cellular contexts and interactions.
• Stratification of EZH2 mutations based on canonical protein sequences.
• Discussion of recent data on the EZH2-H3K27me3 relationship in cancer.

Main Results:

• EZH2 function extends beyond histone methylation, involving interactions with other proteins influenced by cellular context.
• Mutational studies reveal the need for standardized classification of EZH2 mutations (somatic and germline).
• The relationship between EZH2, H3K27me3 levels, and cancer is complex and context-dependent.

Conclusions:

• EZH2 is a significant player in cancer pathogenesis through both canonical and non-canonical mechanisms.
• Standardized analysis of EZH2 mutations is crucial for understanding its role in diseases like Weaver's syndrome and cancer.
• Understanding the nuanced EZH2-H3K27me3 interplay in specific cellular environments is key to targeting EZH2 therapeutically in cancer.