# Coordinate roles of histone H3K27me3 and DNA methylation in intestinal homeostasis and tumorigenesis

> **NIH NIH K01** · DANA-FARBER CANCER INST · 2020 · $14,038

## Abstract

Project Summary
Expression of distinct transcription factors and changes in chromatin states together determine cell-
specific gene expression during differentiation of stem and progenitor cells. Defective chromatin
and gene dysregulation are integral aspects of tumors such as colorectal cancer, and expression of
EZH2 – a catalytic subunit of Polycomb Repressive Complex (PRC) 2, which places the repressive
histone mark H3K27me3 – is also commonly elevated in colorectal and other cancers. However,
the roles and mechanisms of epigenetic modulation in intestinal stem cell (ISC) differentiation and
homeostasis remain poorly understood, particularly the relation of H3K27me3 to other epigenetic
modifications such as DNA methylation (DNAme). Studies in cancer cell lines or ES cells hint at
coordinated gene repression by these alternative processes. However, determinants and reciprocity
of the interactions have not been studied critically in vivo, and investigation of repressive chromatin
marks lags far behind pre-clinical and clinical development of drugs that affect various epigenetic
processes, including small-molecule EZH2 inhibitors. This proposal builds on a general principle we
recently uncovered regarding H3K27me3 function in adult tissues and on two additional unexpected
observations: Genes massively derepressed in mature PRC2-null intestinal cells are unaffected in
ISCs, and H3K27me3-marked genes acquire extensive DNA neomethylation when PRC2 is absent.
I propose to study the interdependence of DNAme and PRC2-mediated H327me3 in ISC and
mature cell gene expression, differentiation, and tumorigenesis. I will first use engineered mouse
models and crypt organoid cultures to eliminate activity of either or both these modifications (Aim1).
I will study the consequences using ChIP-seq for the H3K27me3 and other chromatin state
modifications, RNA-seq for deep transcriptome analysis, and whole-genome bisulfite sequencing
(WGBS) to assess aberrant DNAme. These experiments will elucidate the functional and temporal
interactions of H3K27me3 with DNAme for the first time in adult mammalian cells. Secondly, I will
extend the questions to mouse models that I have generated for increased or absent EZH2 activity
in intestinal tumors (Aim 2). Unexpectedly, I find that EZH2 overexpression reduces, while PRC2
deficiency increases, tumor load significantly. I will characterize tumors that arise in each condition,
establish gene expression signatures for tumors with each modulation, and test their dependence
on H3K27me3-mediated gene silencing as well as the role of altered DNAme in gene regulation in
tumor-derived ISCs. Together, these studies will shed new light on mechanisms of gene silencing in
tissue homeostasis and on the functions of specific repressive chromatin modifications in tumors.

## Key facts

- **NIH application ID:** 9830643
- **Project number:** 5K01DK113067-03
- **Recipient organization:** DANA-FARBER CANCER INST
- **Principal Investigator:** Unmesh Jadhav
- **Activity code:** K01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $14,038
- **Award type:** 5
- **Project period:** 2018-01-01 → 2019-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9830643

## Citation

> US National Institutes of Health, RePORTER application 9830643, Coordinate roles of histone H3K27me3 and DNA methylation in intestinal homeostasis and tumorigenesis (5K01DK113067-03). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9830643. Licensed CC0.

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