Epigenetic Switches That Drive MYC Gene Amplification in Aggressive Cancers

For more than four decades, the MYC protein has stood as one of the most tantalizing and frustrating targets in cancer research. It is dysregulated in an estimated 70 percent of all human malignancies, fueling relentless cell growth, aggressive tumor behavior, and resistance to treatment. Yet because MYC lacks a defined physical binding pocket, conventional small-molecule drugs have been unable to latch onto it and shut it down, earning it a permanent place on the list of so-called undruggable cancer proteins. Now, researchers at the Cancer Epigenetics Institute at Fox Chase Cancer Center in Philadelphia report a way around that barrier, and their answer is as surprising as it is consequential: instead of attacking the MYC protein itself, they targeted the epigenetic machinery that decides whether the MYC gene gets copied in the first place.

The new study, published in the journal Molecular Cell and led by Johnathan R. Whetstine, director of the Cancer Epigenetics Institute, demonstrates that gene copy-number amplification, long viewed as a random byproduct of genomic chaos, is in fact a biologically regulated process governed by specific chromatin machinery. By identifying the enzymatic gatekeepers that control how MYC amplification begins and progresses, the team has opened a potential therapeutic route that sidesteps the protein entirely and instead constrains the DNA structural events that multiply the gene. According to Whetstine, this strategy of targeting the DNA structural assembly line rather than the finished protein could have relevance for at least 30 percent of all cancers.

The technical heart of the discovery lies in two chromatin-regulating proteins, KDM4C and SETD2, which the researchers found act as gatekeepers controlling access to the MYC gene region. SETD2 is a histone methyltransferase that helps maintain a stable, properly marked chromatin environment, while KDM4C is a histone demethylase that remodels the epigenetic landscape. Under normal conditions, these enzymes help keep DNA packaged and regulated within the cell. But when SETD2 is lost or blocked, KDM4C gains improper access to the MYC locus and alters the surrounding DNA environment. Tumors, the team found, frequently increase KDM4C levels, which further drives the deleterious amplification process.

Using human cell models, genomic analyses, and mouse studies, the researchers showed that KDM4C does more than loosen chromatin. It actively recruits the cell’s DNA-copying machinery to the MYC region, causing the gene to be copied repeatedly and generating extra MYC copies. The effect was not circumstantial. In a striking proof of causality, the team used dCas9 technology to direct KDM4C to the MYC region artificially, and that alone was sufficient to trigger amplification, even in cells with a completely normal set of chromosomes. As Benjamin I. Ferman, a PhD student in the Whetstine lab and first author of the study, explained, the findings demonstrate that MYC amplification is not simply a random byproduct of genomic instability, but a process actively controlled by specific epigenetic programs.

Copying MYC, however, is only half the story. The real danger emerges when cells carrying dangerous levels of MYC fail to eliminate themselves. MYC overactivation normally triggers programmed cell death, a built-in safeguard against runaway proliferation. The researchers found that disabling this fail-safe allowed hyperamplification and tumor formation to proceed. When cells lost their normal ability to undergo apoptosis, abnormal MYC amplifications could reach high levels and continue expanding. This effect was especially pronounced when cells also lost TP53, a crucial tumor suppressor gene that normally helps eliminate damaged cells before they can do harm.

Over time, the combination of disrupted epigenetic control and TP53 loss drove MYC amplification to high levels, including the formation of circular extrachromosomal DNA, a notoriously aggressive form of oncogene amplification that can accelerate tumor evolution and drug resistance. In mouse models, the consequences were decisive: the starting cells were non-transformed and did not cause tumors without MYC amplification, but once the epigenetic program ran its course and cellular defenses failed, tumor formation followed. The findings suggest that MYC amplification develops in stages, with chromatin changes first triggering the formation of extra gene copies, and the failure of normal defense mechanisms then allowing those abnormal cells to survive, spread, and grow more aggressive. Whetstine notes that this staged relationship echoes the Two-Hit Theory of cancer causation, the landmark concept originated at Fox Chase by Alfred Knudson.

The translational implications are significant. Because the newly identified regulatory mechanisms contain enzymatic targets, they could in principle be exploited through small-molecule drug development, opening therapeutic avenues for MYC-driven cancers that have resisted every conventional approach. The Whetstine lab found that blocking KDM4C activity, either genetically or with targeted drugs, reduced MYC amplification across multiple experimental systems, including MYC-amplified cancer cells and animal models. Notably, a clinically used KDM4 inhibitor successfully suppressed MYC amplification in vivo, an early proof of concept that a challenge long considered untouchable may be addressable in the clinic.

Beyond drug development, the work points to a new biomarker paradigm. If specific epigenetic imbalances, such as SETD2 loss combined with elevated KDM4C, reliably predict which tumors are poised to develop aggressive amplification states, clinicians could potentially identify high-risk cancers earlier and intervene before extrachromosomal DNA and treatment resistance take hold. Whetstine emphasized that MYC amplification appears to be far more dynamic and controlled than previously appreciated, raising the possibility that these amplification states could be therapeutically constrained rather than simply endured. Biomarker and therapeutic studies are already under development at the Cancer Epigenetics Institute and Fox Chase.

The research was supported by the National Institutes of Health and developmental funding from Fox Chase Cancer Center. In addition to the Fox Chase team, collaborators from Massachusetts General Hospital, Harvard Medical School, Stanford University, the Broad Institute, and the Icahn School of Medicine at Mount Sinai contributed to the study. Taken together, the findings reframe one of cancer biology’s oldest puzzles: the amplification of a master growth gene is not a stochastic accident but a regulated epigenetic program with identifiable switches, and those switches, unlike the MYC protein itself, may finally be druggable.

Subject of Research: Epigenetic regulation of MYC gene amplification in aggressive cancers

Article Title: Cracking the 'undruggable' code: Fox Chase Cancer Center researchers unveil epigenetic blueprint fueling aggressive MYC amplification driving cancer

Article References: Cracking the 'undruggable' code: Fox Chase Cancer Center researchers unveil epigenetic blueprint fueling aggressive MYC amplification driving cancer. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: MYC, gene amplification, epigenetics, KDM4C, SETD2, extrachromosomal DNA, TP53, chromatin, undruggable targets, Fox Chase Cancer Center, Molecular Cell, cancer therapy