Now That We Can Edit Cancer's Genes, We Can Make Better Drugs

The ability to edit the human genome, a sci-fi procedure made possible by a new technique called CRISPR/Cas-9, has taken the field of genetic research by storm. In the last year alone, hundreds of papers have been published using CRISPR. We're so good at using it, in fact, that those who treat diseases have bigger concerns.

At least, that's according to Jason Moffat, principal investigator at the University of Toronto's Moffat Lab. His team published a paper Wednesday in Cell describing how they used CRISPR to identify which genes express the proteins that make certain types of cancer cells grow, and knock them out. Adios, cancer.

It's impressive work, and some have already speculated that editing diseases right out of existence is the near-future of treatment. But when I spoke to him on the phone, Moffat told me that's not quite the case. While CRISPR is useful for finding the parts of the cancer cell that govern growth, they still need to be targeted by other drugs—and those are what we don't have just yet.

"With this CRISPR technology, we can now systematically go through all our biological models for cancer and map out all the tricks cancer cells have to evade drug responses," he explained. "If we can figure out what to target for every one of those cancers, we can actually build a warchest of therapeutic drugs to target all these different tricks that cancer cells use to grow and divide."

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In other words, using gene-editing to map out various cancers' weak points is the easy part. The hard part is finding the right drugs for the job. "That's the holy grail, to get to that place," Moffat said.

Moffat's team's work is the third entry in a trio of papers all published independently of one another within the span of little more than a month, all covering the same ground. Basically, they used gene editing techniques to screen cell types, including cancer, for the core genes that express the proteins most important for their growth and survival. Taken together, it's not a stretch to call these advances game-changing.

To get a little more in-depth as to how it all works, here's what Moffat's team did: first, they designed a library of 180,000 CRISPR "guides," which knock out a specific gene when applied to a cell. Next, they introduced this library to a large population of millions of cells so that each cell got one CRISPR guide, and then set up what Moffat called a kind of "fight club" competition to see which cells grew and which didn't. If a cell's growth was stifled by the applied CRISPR guide, then viola, there you have the protein that acts as the engine for that cell's growth. And those proteins are what need to be targeted in the body with drugs or other treatments.

"It's not going to be so much about our ability to edit the genome going forward, because we're actually really efficient about that now with CRISPR," said Moffat. "It's opened up a whole new world."

Welcome to the future, where apparently the ability to finely-tune and edit the building blocks of life itself is the least of our problems.