PRC1 Polycomb complex shown to suppress tumour formation in adult Drosophila intestinal stem cells

Researchers publishing in PLOS Genetics have used a novel Drosophila model to investigate the role of Polycomb Repressive Complex 1 (PRC1) in adult intestinal stem cells (ISCs). The study, led by Aurélia Joly and colleagues including researchers associated with Armel Gallet's and Anne-Marie Martinez's groups, reports that loss of PRC1 function disrupts ISC identity and drives tumour-like overgrowth, establishing a direct tumour-suppressive function for the complex in this tissue context.

Polycomb group (PcG) proteins are epigenetic regulators that silence gene expression through histone modification; PRC1 specifically catalyses monoubiquitination of histone H2A. PcG proteins are frequently mutated or dysregulated in human cancers, but their precise role in stem cell compartments during tumourigenesis has remained difficult to disentangle from their broad developmental functions. This work offers a genetically tractable in vivo system in which to probe those relationships.

The authors developed their Drosophila intestinal model to separate homeostatic from tumourigenic roles of PRC1, finding that the complex is required to maintain the transcriptional programme that defines ISC identity. When PRC1 was disrupted, cells lost identity markers and underwent uncontrolled proliferation. The findings add to a growing body of work linking chromatin-level gene regulation to cancer initiation in stem cell populations, with potential conceptual relevance to colorectal and other epithelial cancers where PcG mutations are observed.