Researchers have cracked the code on how bacteria naturally manufacture multiple versions of powerful cancer-fighting compounds, a breakthrough that could accelerate the development of next-generation therapies for hard-to-treat cancers.
The discovery, published in Nature Communications, solves a decades-old puzzle: scientists knew bacteria could produce variants of anti-cancer drugs, but had no idea how they coordinated the process. The new findings reveal that tiny molecular connectors called docking domains act as the key to nature's drug-making system, allowing different enzymes to communicate and pass their products along an assembly line with remarkable precision.
"For decades, we've known that bacteria can naturally produce multiple versions of powerful anti-cancer drugs, yet we had no idea how they achieved this," said Dr. Munro Passmore, Research Fellow in the Department of Chemistry at the University of Warwick. "This work finally cracks that code. It's the breakthrough we needed to actually engineer these drugs ourselves."
The research focuses on a class of cancer medicines called HDAC inhibitors, which work by blocking enzymes that control which genes are activated inside cells. Romidepsin (Istodax), an FDA-approved treatment for certain blood cancers like T-cell lymphomas, belongs to this family. Scientists had long identified a chemically related compound called FR-901375, but the biological pathway bacteria used to manufacture it remained a mystery until now.
Inside bacterial cells, these drugs are assembled by massive protein complexes that combine two different enzymatic systems: polyketide synthase and nonribosomal peptide synthetase. These work together to build complex ring-shaped molecules using amino acids and other chemical building blocks. The docking domains discovered in this study function as molecular connectors, allowing one enzyme to recognize and hand off its partially built product to the next enzyme in the line.
The team used a combination of cutting-edge techniques to map out this system. Researchers scanned genetic databases to identify the genes responsible for producing FR-901375 in a bacterium called Pseudomonas chlororaphis subsp. piscium. They then used laboratory experiments to show that purified protein domains could interact productively, employed artificial intelligence tools like AlphaFold to predict how the proteins fit together, and conducted genetic experiments in living bacteria to confirm their findings.
Understanding this natural "mix and match" system opens the door to what scientists call combinatorial biosynthesis: the ability to engineer bacteria to produce entirely new drug variants tailored for specific cancers. Rather than waiting for nature to stumble upon effective compounds, researchers can now deliberately design synthetic pathways that generate candidates with improved potency, better selectivity for cancer cells, and fewer side effects.
"This research gives us a blueprint to do what nature does, but better and faster," said Prof. Greg Challis, a leading researcher on the project based at the University of Warwick and Monash University. "By reverse-engineering nature's evolutionary logic, we can now design synthetic pathways that generate new anti-cancer drug candidates with properties optimized for clinical use. Our immediate goal is to build an expanded library of candidates for various cancers where new treatments are urgently needed."
The study also reveals how these natural drug-producing systems evolved. The researchers determined that FR-901375's production pathway likely arose from a related drug-producing pathway through gene duplication and recombination, a pattern that appears to be conserved across multiple bacteria that manufacture HDAC inhibitors.
The implications extend beyond cancer alone. The docking domain mechanism uncovered here may apply to other natural product biosynthetic systems, potentially accelerating drug discovery across multiple therapeutic areas. Researchers now have the tools and knowledge to systematically generate new compounds rather than relying on random screening or serendipitous discovery.
Author Jessica Williams: "This is the kind of foundational science that transforms drug development from guesswork into engineering, and for patients waiting for better cancer treatments, the timing couldn't be better."
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