Imagine a world where we could precisely control the switches that turn cancer on and off. That's the promise of a groundbreaking discovery by HKU chemists, who have developed a novel inhibitor targeting a crucial epigenetic regulator. This could revolutionize how we treat non-small cell lung cancer (NSCLC), offering a new hope for patients.
Figure 1. Tumour suppression in vivo — In animal models, LS-170 treatment significantly reduced tumour volume, demonstrating its strong anti-cancer potential. (Image adapted from the relevant journal.)
A team of researchers, spearheaded by Professor Xiang David Li from the Department of Chemistry at The University of Hong Kong (HKU), in collaboration with scientists from the Shenzhen Bay Laboratory and Tsinghua University, has achieved a major breakthrough in the realm of epigenetic drug discovery. They've successfully engineered a first-in-class chemical inhibitor. This inhibitor acts with laser-like precision to target the ATAC complex. Think of the ATAC complex as a master "switch operator" within our cells, responsible for activating genes that promote tumor growth, especially in NSCLC. This discovery, recently published in Nature Chemical Biology and backed by multiple international patent applications, opens an entirely new avenue for treating this devastating disease.
But what exactly is epigenetic regulation, and why is it so important?
Let's delve into the fascinating world within our cells to understand.
Histone Modifications: The Tiny Genetic Switches Controlling Our Cells
Deep inside our cells, our DNA isn't just floating around. It's carefully packaged around protein structures called histones, forming a complex called chromatin. Now, these histones aren't just passive packaging material. They're covered in chemical modifications that act like genetic "switches," dictating whether a gene is turned on (expressed) or remains silent (repressed). It's like having a dimmer switch for each gene, controlling how brightly it shines.
Among these modifications, histone acetylation is a particularly important "on" switch. When a histone is acetylated, it's like flipping a light switch, activating gene expression. This process is orchestrated by enzyme complexes known as histone acetyltransferases (HATs).
The ATAC complex is one of these HAT complexes, and it plays a crucial role in turning on genes involved in cell growth, division, and DNA replication. In cancers like NSCLC, however, the ATAC complex goes haywire. It becomes overactive, inappropriately flipping the "on" switch for numerous cancer-driving genes. This fuels uncontrolled tumor growth and spread, turning healthy cells into cancerous ones.
The Challenge: Selective Targeting
For years, scientists have recognized the potential of targeting the ATAC complex to fight cancer. But here's where it gets controversial... Selectively inhibiting ATAC without disrupting other essential cellular processes has been a major hurdle. Previous attempts to develop drugs targeting ATAC have stumbled because they lacked the necessary precision.
Professor Li's Innovative Solution: Targeting YEATS2
Previous drug-development efforts mainly focused on inhibiting GCN5. GCN5 is the catalytic subunit responsible for histone acetylation within the ATAC complex. The problem? GCN5 isn't exclusive to ATAC. It's also shared by several other HAT complexes, meaning that blocking it would inadvertently interfere with normal cellular functions and lead to significant side effects. Imagine trying to fix a specific wire in your car's engine by just blindly cutting wires. You might fix the problem, but you'll probably break a lot of other things in the process.
To overcome this challenge, Professor Li's team devised an ingenious strategy: targeting YEATS2, a protein subunit specific to the ATAC complex. And this is the part most people miss... By focusing on a unique component, they could potentially shut down ATAC without affecting other vital cellular processes.
Using a technique called structure-guided design, the researchers developed a potent and highly selective inhibitor of YEATS2, which they named LS-170. This inhibitor works like a lock and key, specifically binding to the acetyl-lysine recognition domain of YEATS2. This prevents YEATS2 from properly anchoring the ATAC complex to chromatin, the DNA-histone complex. As a result, the ATAC complex is displaced from its target genomic regions, leading to a significant reduction in local histone acetylation and the "off" switching of oncogenes in NSCLC. It's like removing the key that turns on the cancer-promoting genes.
Promising Results: Suppressing Tumour Growth and Metastasis
In NSCLC cell lines and animal models, LS-170 demonstrated remarkable efficacy in suppressing tumor growth and metastasis. The results were so promising that they suggest LS-170 could be a game-changer in the treatment of NSCLC.
Notably, the YEATS2 gene is frequently amplified in multiple solid tumors—including lung, ovarian, and pancreatic cancers—suggesting that this targeted strategy may hold broader therapeutic potential beyond lung cancer. This means that LS-170, or similar inhibitors, might be effective against a range of different cancers.
This study represents the first chemical approach to precisely decode the function of a specific HAT complex, revealing ATAC's distinct role in maintaining gene expression programs in cancer. It also offers new insights for developing other complex-specific epigenetic drugs for human diseases. The implications are enormous.
"In this work, we didn't just create a potent and highly specific inhibitor that can suppress tumours, we also uncovered a novel strategy to target just one epigenetic complex out of several that share the same enzyme core. This approach opens up exciting possibilities for developing highly selective, complex-specific drugs that could potentially revolutionise treatments for human diseases," said Professor Xiang Li, one of the corresponding authors of the paper.
About the Research Team:
The interdisciplinary collaboration was led by Professor Xiang David LI (HKU Chemistry), together with Professor Weiping WANG (HKU Pharmacology and Pharmacy), Researcher Xin LI (Shenzhen Bay Laboratory), and Professor Haitao LI (Tsinghua University). Co-first authors included Dr Sha LIU, Dr Yin Qiao WU, Dr Jinzhao LIU, and Dr Xinyi YAO.
For more details, please refer to the journal paper: https://www.nature.com/articles/s41589-025-02132-7
The Big Question: Are Complex-Specific Drugs the Future of Cancer Treatment?
This research raises a fascinating question: Could targeting specific epigenetic complexes, like ATAC, be the key to unlocking more effective and less toxic cancer therapies? While the initial results are promising, further research is needed to fully understand the potential and limitations of this approach. What do you think? Could this be the future of cancer treatment, or are there potential drawbacks we haven't considered? Share your thoughts in the comments below!
