On December 9, 2025 Promega reported a new study published in Nature Communications reveals technological advances that accelerate breakthroughs in precision medicine. Conducted as a collaboration between Promega, the Center for Advanced Study of Drug Action at the State University of New York at Stony Brook, and the Centre for Medicines Discovery at the University of Oxford, the work leverages bioluminescent NanoBRET Target Engagement (TE) technology developed by Promega to characterize inhibitors that selectively target cancer cells without harming noncancerous cells. Their results demonstrate a connection between drug efficacy and tumor metabolic state, offering a mechanistic bridge between cancer metabolism and precision oncology.
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"To our knowledge, this is the first time anyone has characterized this type of uncompetitive inhibitor mechanism directly in live cells." -Ani Michaud, Sr Research Scientist at Promega
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"The methods in this study enable us to characterize inhibitors that bind much more tightly in tumor cells with specific mutations," says Ani Michaud, Sr Research Scientist at Promega and co-first author of the Nature Communications paper. "To our knowledge, this is the first time anyone has characterized this type of uncompetitive inhibitor mechanism directly in live cells."
PRMT5: Top Target for Drug Discovery
The published study focuses on a gene-regulating protein called PRMT5, which has long been considered a top target for drug discovery. In normal cells, PRMT5 interacts with a molecule called SAM. However, in the tumor cells of approximately 10-15% of cancers, a deletion of the MTAP gene leads to PRMT5 interacting with the molecule MTA instead, reducing its function. This difference creates a key vulnerability for targeting cancer cells with a mutation to MTAP while leaving normal cells unaffected.
The University of Oxford team designed and developed CBH-002, a cell-permeable BRET probe that binds to a genetically encoded PRMT5-NanoLuc biosensor to report drug target engagement in live cells.
Dr Elisabeth Mira Rothweiler, Postdoctoral Researcher, Centre for Medicines Discovery, University of Oxford and co-first author, says: "CBH-002 could measure various PRMT5 inhibitor types in live cells, prompting us to test its sensitivity to the cofactor SAM. When we discovered the probe’s ability to sense metabolite levels, it established its utility as a metabolic biosensor. Through collaboration with Promega, we demonstrated how MTA influences drug selectivity, revealing why certain inhibitors are so effective in MTAP-deleted cancers."
Dr Rothweiler’s research further enables a strategy for developing molecules that exploit the metabolic vulnerabilities specific to MTAP-deleted cancers, potentially offering highly targeted treatments with minimal effects on healthy tissue.
Uncompetitive Binding in Live Cells
While past studies have characterized this mechanism-of-action (MoA) in biochemical assays, this is the first to use NanoBRET TE technology to characterize uncompetitive, or cooperative, binding in live cells. Biochemical assays can reveal uncompetitive MoAs, but there is often a discrepancy between biochemical data and functional assays like selective cell killing. The NanoBRET TE assay used in this study bridges the two modalities, showing binding MoA in a cellular context that aligns with functional assay results.
Professor Kilian Huber, Associate Professor, Centre for Medicines Discovery, University of Oxford and co-senior author of the study, says, "The biosensor lets us examine, in living cells, how different PRMT5 inhibitors behave under the specific metabolic conditions that make some tumors uniquely vulnerable. This provides unprecedented insight into why certain inhibitors are much more effective in cancers lacking MTAP and paves the way for highly targeted cancer treatment in the future. It’s like turning on the lights inside the cell so we can finally see which key actually fits the lock."
"Selectivity is one of the most critical challenges in cancer therapy, as most treatments also damage healthy cells, leading to dose-limiting toxicities and reduced therapeutic effectiveness," says Peter Tonge, distinguished professor of chemistry and director of the Center for Advanced Study of Drug Action at the State University of New York at Stony Brook and visiting professor at the University of Rochester. "A new class of tumor-specific drugs addresses this by acting uncompetitively with a metabolite that accumulates only in cancer cells, limiting activity to tumor tissue. We have now developed the first technology to quantify the activity of these drugs directly in live cells, providing a foundation for optimizing and advancing next-generation precision oncology therapeutics."
Collaboration Between Academia and Industry
This study was the result of collaboration between Promega, the Center for Advanced Study of Drug Action at the State University of New York at Stony Brook, and the Centre for Medicines Discovery at the University of Oxford, with additional contributions from researchers at Boston University and the Structural Genomics Consortium at the University of Toronto.
"This work underscores the value of research collaborations between academia and industry," says Matt Robers, Associate Director of R&D at Promega and co-senior author of the study. "By combining our complementary expertise in chemical biology and assay design, we were able to dissect how cooperativity can drive cancer cell selectivity. These findings have real potential to guide the development of future precision medicines."
Read the paper "A BRET biosensor for measuring uncompetitive engagement of PRMT5 complexes in cells" in Nature Communications here: View Source
(Press release, Promega, DEC 9, 2025, View Source [SID1234661337])