Obtaining compounds from nature, such as opioids from poppies or taxol from yew trees, is hard and time-consuming. So researchers, including Stanford's Christina Smolke, PhD, are working to synthesize medically useful compounds by reengineering nature.
Smolke, a professor of bioengineering, describes her efforts to engineer yeast to make opioids on a recent episode of the “Future of Everything” radio show.
“These are compounds in nature that the opioid poppy has evolved to make. And to date, our chemists have not been able to develop efficient processes to make these compounds,” Smolke told show host Russ Altman, MD, PhD, a professor of bioengineering, of genetics, of medicine and of biomedical data science. “So we still farm this drug crop of opioid poppy to produce these molecules and the raw materials to make these molecules. And there are many limitations that come about from doing that.” These limitations include environmental and geopolitical risks, she said.
Smolke explained that she tackled the project even though many experts in the field viewed it as impossible — because it involved reengineering a complicated set of reactions and mix of enzymes that work together within the opioid poppy to build the opioid molecules. Over 10 years, her research team developed the very challenging platform technology to "prove that it could be used with any compound found in nature."
“The final yeast strain that made the initial opioid molecules had 23 different enzymes put into it. So one of the challenges was identifying the enzymes from the opioid poppy and then moving them into yeast,” Smolke said.
But the trickiest part, she explained, was getting them to work in yeast, which is a very different organism than opioid poppies. The researchers had to modify each of the enzymes to create a yeast strain that could churn out opioid molecules.
There is more work to do though, including developing yeast that are more efficient at making the opioid compounds, as well as using the technology to make better opioids with fewer side effects so they are less addictive. Luckily, Smolke expects her new research projects to go more quickly now that they’ve developed the basic tools.
“We’re probably around five years away from molecules coming from yeast-based platforms to actually be in the medications that you’re taking,” Smolke explained. “Some of that lag is due to the engineering that we have to do to make the processes efficient enough so they can be scaled up at a commercial setting. And others are [due to] regulatory approvals.”
Previously: Repeal of ACA would worsen opioid epidemic, Stanford researcher says, Existing drug found to limit some side effects of opioids in mice and Cancer drug produced in common plant
Thumbnail photo by papaya45