Scientists have uncovered a surprising new role for hydralazine, a long-used blood pressure medication. While the drug has been prescribed since the 1950s, its precise mechanism of action was unclear. A new study from the University of Pennsylvania reveals that hydralazine directly interferes with a key cellular enzyme linked to the survival of aggressive tumors, offering a potential path toward repurposing the medication for cancer therapy.
How Hydralazine Interacts with Cancer Cells
Researchers discovered that hydralazine targets an enzyme called 2-aminoethanethiol dioxygenase, or ADO. This enzyme acts as a cellular oxygen sensor, helping cells endure low-oxygen environments. Tumor types such as glioblastoma rely heavily on this mechanism because they grow so rapidly that their blood supply cannot keep up. As oxygen levels fall, ADO enables the cancer cells to survive and continue dividing.
Advanced techniques, including X-ray crystallography, showed that hydralazine binds directly to ADO and shuts it down. By disabling this oxygen-response system, the drug forces cancer cells to stop dividing, disrupting one of their core survival pathways.
Laboratory Results Offer Early Insight
To evaluate the discovery, the research team treated human glioblastoma cells with hydralazine. Within three days, the cells stopped multiplying and entered a state known as senescence, a permanent growth-arrested condition. Although the drug did not kill the cells outright, it removed their ability to grow and spread, a major challenge in treating cancers known for recurring even after aggressive intervention.
A Potential Path to Faster Cancer Therapies
Because hydralazine is already FDA-approved for hypertension, researchers hope that any future cancer-related use could progress more quickly than that of new experimental drugs. The findings, however, are still at an early stage. All experiments so far have involved cell cultures, and further work is needed to understand whether blocking ADO is safe and effective in living organisms.
Scientists emphasize that this discovery marks a starting point rather than a ready-to-use treatment. Understanding hydralazine’s molecular behavior opens the door to developing more selective therapies that target tumor survival mechanisms with greater precision.
Conclusion
The identification of hydralazine’s interaction with ADO sheds new light on an old medication and provides a promising foundation for cancer research. While clinical applications remain distant, the study offers a potential pathway toward future therapies for some of the most treatment-resistant tumors.