World’s oldest common blood pressure drug may slow deadly brain tumor, New Research Shows

A decades-old blood pressure drug may help slow the growth of one of the deadliest forms of brain cancer, new research from Weill Cornell Medicine and the University of Pennsylvania suggests.

Hydralazine — a medication used since the 1950s to treat high blood pressure — has unexpectedly shown potential to combat aggressive tumours like glioblastoma. Scientists discovered, while studying how the drug actually works, something that had remained unclear despite its long history.


How the Discovery Happened

Dr Kyosuke Shishikura, a physician-scientist at the University of Pennsylvania, said hydralazine comes from a “pre-target era” of drug development — when medicines were tested on patients first, and the biological mechanism was understood only later.


During their research, the team uncovered that hydralazine directly targets a small but critical enzyme called 2-aminoethanethiol dioxygenase (ADO).

Why ADO Matters in Cancer

ADO works like a tiny oxygen sensor inside cells — an “alarm bell” that activates the moment oxygen levels drop, explained Dr Megan Matthews, a co-researcher and assistant professor in Penn’s Department of Chemistry.

In fast-growing tumours such as glioblastoma, cancer cells multiply so rapidly that parts of the tumour become oxygen-deprived. Normally, healthy cells die without oxygen. But cancer cells activate special survival pathways — many of which are controlled by ADO — that help them keep dividing even under low-oxygen stress.

Hydralazine Silences the Tumour’s Survival Alarm

Using advanced tools like X-ray crystallography, researchers found that hydralazine binds directly to ADO and shuts it down.
Once the enzyme is blocked:

* The tumour’s oxygen-survival response stops

* Cancer cells can no longer multiply

* The cells enter “senescence” — a permanent sleep-like state where they stay alive but cannot grow

In lab experiments on human glioblastoma cells, hydralazine stopped cell division within three days. Although the drug did not kill the cells outright, it prevented further spread — a breakthrough for tumours known to return even after surgery and chemotherapy.

Why This Matters

Glioblastoma is one of the most aggressive brain cancers, with extremely poor survival rates and high recurrence. A drug like hydralazine — already FDA-approved and widely available — could potentially fast-track new treatment approaches.

However, researchers caution that the results so far are limited to cell studies. Hydralazine has not yet been tested on animals or humans in this context.

The team’s findings mark only the beginning of what could become a promising new direction in cancer therapy through drug repurposing.