# Cancer Epigenetics:  A novel PRC2 Dysregulation Mechanism in Multiple Myeloma

> **NIH NIH R01** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2020 · $390,643

## Abstract

PROJECT SUMMARY/ABSTRACT
Multiple myeloma (MM) is a common, devastating hematological cancer with a low rate of overall survival and
a need for development of new treatments. Recent genome-wide profiling of MM patient samples has revealed
a globally perturbed pattern of histone methylations underlying MM pathogenesis; in particular, an enhanced
level of H3K27me3 (tri-methylation of histone H3, lysine 27) correlates well with aberrant gene silencing and
with MM progression to the aggressive stage. H3K27me3 is produced by Polycomb Repressive Complex 2
(PRC2), a histone methyltransferase complex that employs either EZH2 or EZH1 as an enzymatic subunit.
However, direct sequencing of MM patient samples identified no mutation of EZH2, EZH1 or other PRC2
genes. The mechanisms responsible for H3K27me3 dysregulation during pathogenesis of MM remain elusive.
We recently found that aberrant amplification and over-expression of PHD Finger Protein 19 (PHF19), a gene
previously reported by us to encode a new regulator of PRC2, occurs frequently in MM patients and predicts a
poor clinical prognosis. We also found that aberrantly expressed PHF19, as well as its interaction with PRC2,
is required for tumorigenicity of MM in vitro and in vivo. Mechanistically, PHF19 dramatically enhances
chromatin occupancy of PRC2, causing H3K27 hypermethylation in MM cells. Intriguingly, MM differs from
many cancers by the high expression of EZH1, a less studied H3K27 methyltransferase enzyme, which
significantly contributes to MM cell growth and H3K27me3 dysregulation. We hypothesize that aberrant PHF19
amplification and overexpression represents an important MM-promoting mechanism that confers aggressive
tumor features and epigenetic perturbations through hyper-activation of EZH1 and EZH2 H3K27 methyl-
transferase enzymes. Dissecting the molecular events and mechanisms underlying PHF19-mediated MM
tumorigenicity should provide critical insights into new anti-MM strategies. Towards this goal, we will determine
whether overexpression of PHF19 is necessary and sufficient to promote tumorigenesis in rigorous cancer
models of MM including a patient-derived xenograft model (aim 1); we will characterize effects of PHF19
overexpression on chromatin occupancy of PRC2 and epigenetic gene deregulations in MM cells through
unbiased ChIP sequencing and transcriptome profiling approaches (aim 2); and third, we will use a combined
genetic (CRISPR/cas9) and pharmacological (inhibitor) approach to determine whether both EZH1 and EZH2
are crucial effectors of PHF19-mediated tumorigenesis in MM (aim 3). Significant to the proposed research is
that we will evaluate anti-MM therapeutic effects of a unique small-molecule inhibitor of EZH1 and EZH2
recently discovered by our laboratories. We expect to fully delineate an important, yet unexplored oncogenic
pathway in MM by functionally characterizing PHF19 with rigorous cancer models, gain a mechanistic
understanding, and determine oncogenic effector...

## Key facts

- **NIH application ID:** 9852883
- **Project number:** 5R01CA211336-04
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** G Greg Wang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $390,643
- **Award type:** 5
- **Project period:** 2017-02-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9852883

## Citation

> US National Institutes of Health, RePORTER application 9852883, Cancer Epigenetics:  A novel PRC2 Dysregulation Mechanism in Multiple Myeloma (5R01CA211336-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9852883. Licensed CC0.

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