GM Plants Offer New Source of Anticancer Drugs

Developing insect-proof and herbicide-tolerant plants by genetic engineering is not new. Scientists have known for years how to trick plants into producing their own insect-killing substances by inserting genes from other plants or animals. What is new, however, is the ability to induce plants to create new products by tinkering with the plants' own metabolic machinery. Using this approach, a team of researchers from the Massachusetts Institute of Technology (MIT) have successfully developed periwinkle plants accumulating novel compounds, some of which could be used as drugs against cancer and other diseases. This sort of manipulation, the scientists say, offers a new way to tweak potential drugs to make them less toxic and more effective.

Periwinkle (Catharanthus roseus) produces many compounds of pharmacological interest, including the alkaloid vinblastine which is used to treat cancers such as Non-Hodgkin’s Lymphoma, anticancer agents called serpentines and ajmalicine, a substance used to treat hypertension. Almost all of the compounds produced by periwinkle, however, are too toxic for use in humans.

Sarah O'Connor and colleagues modified an enzyme involved in an early step of the plant’s alkaloid synthesis pathway. The enzyme was also altered to accept substrates it would not normally use. This allows plants to make new compounds that they would normally never produce.

Read the complete article at http://web.mit.edu/newsoffice/2009/plant-drug-0118.html. The paper published by Nature Chemical Biology is available at http://dx.doi.org/10.1038/nchembio.141