Unlocking periwinkle鈥檚 potent secrets
When she was a child and had a cold, Vonny Salim 鈥07 wasn鈥檛 dosed with medicine from a bottle. Instead her mother fed her garlic, 鈥渨hich is nasty, but works,鈥 Salim said. 鈥淎nd she made a drink from the leaves of a plant to treat my dad鈥檚 high blood pressure. She taught me the power of nature to heal.鈥
Salim wondered why plants could heal. What was going on inside them to make such medicine?
鈥淚 was quite a biology nerd,鈥 she admitted.
Her questions took her from her native Indonesia to Seattle to study biology and chemistry.
鈥淚n Seattle my host family had two members suffering from cancer. That made me sad, and it focused my study. I thought, 鈥楥ouldn鈥檛 we find something from plants to cure cancer?鈥欌
The question lodged deeply. When she transferred to 17c起草社区, Salim learned from biology professor David Koetje the principles of plant biotechnology, and, in the lab with professor John Beebe, she saw how those principles played out in the breeding of hostas.
For her graduate work, she was eager to hone in on plant-based cures for cancer. Where and how to do that? An Internet search suggested: Madagascar periwinkle, Vincenzo De Luca. In September 2008 she began research in De Luca鈥檚 lab at .
Chemists have long known that a chemical compound called vinblastine, produced by the Madagascar periwinkle, inhibits the out-of-control cell growth that characterizes cancer and so is an effective chemotherapy treatment. The problem is that each periwinkle makes only a very small amount of vinblastine. Extracting and purifying these small yields makes vinblastine an expensive drug. If, however, scientists could identify the precise step-by-step pathway along which enzymes catalyze chemical reactions to form vinblastine, then the drug could be synthesized outside periwinkles. Identifying that pathway has been the decades-long work of De Luca鈥檚 lab, the work Salim joined.
Salim and her research partner discovered the reason periwinkles produce such small amounts of vinblastine. In the last step of the chemical pathway that forms the drug, two compounds, catharanthine and vindoline, join. But the plant keeps these compounds largely separated. Salim went on to discover that the reason the plant keeps catharanthine on its leaf surfaces is that the compound is toxic to fungi and larvae that eat the leaves.
The bulk of Salim鈥檚 research now is to identify the genes that control the pathway of enzymatic reactions that produce catharanthine and vindoline.
鈥淭here are multiple genes in the pathway of each compound that we haven鈥檛 identified,鈥 she explained. 鈥淭hose are the genes I鈥檓 looking for. If we know the specific genes that control every single step of the pathway, then we can transfer those genes into a yeast that will release the drug in one step. That will make the drug much more affordable. But I鈥檓 afraid that鈥檚 still a long way off.鈥
The past four years of research have made clear to Salim how long a road it is to her dream of identifying a new plant-based cure for cancer.
鈥淭he first year was rough,鈥 she said. 鈥淚 learned to pray, asking God for direction. Because these systems are complex, and without God鈥檚 direction, you鈥檙e looking for a needle in a haystack. Now it鈥檚 not a burden. I wake up in the morning and say, 鈥榃hat鈥檚 new today, God?鈥 Research isn鈥檛 just an occupation for me. It鈥檚 walking with God.鈥