A natural plant compound may help overcome a built-in defense that allows many cancers to resist a class of drugs designed to restore normal gene activity, according to a study by researchers at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center.

The researchers found that triptolide, a natural compound from Tripterygium wilfordii, commonly known as thunder god vine, blocks an enzyme called DCTPP1 that cancer cells can use to break down DNA methyltransferase inhibitors, or DNMT inhibitors, before the drugs can fully work. When researchers combined triptolide or related compounds with the DNMT inhibitor decitabine, it dramatically boosted the drug’s ability to reactivate tumor suppressor genes and kill cancer cells in laboratory models.

The findings, published Aug. 26 in Nature Communications, suggest a potential strategy for overcoming resistance to DNMT inhibitors and expanding their use to more types of cancer.