“Cancer Cells Cast a Sweet Spell on the Immune System”
by Esther Landhuis
Science News, April 1, 2017
Here’s my proposal for one of the SN feature ideas we discussed by phone a few weeks ago. Do you know approximately when you’ll decide?
Sugars on cancer cells are fueling a revolutionary approach to immunotherapy
Drugs that unleash immune killing of tumors have taken the field by storm, saving former President Jimmy Carter and many others with cancers once incurable. These immunotherapies expose tumors to attack by blocking protein interactions that shield cancer cells from the immune system. But the wonder drugs don’t work for everyone. And they only activate the adaptive immune branch of the body’s defenses.
Researchers are unlocking a new immunotherapy approach that recruits a different line of defense—the innate immune system—and targets sugars instead of proteins.
Here’s how it works. Our cells are coated with sugars, and normally when immune cells meet a cell that “tastes” bad, they attack it. But cancer cells beat the system. They rack up certain sugars that make them deceptively tasty, so when immune cells cozy up, they think the tumor cell’s OK and leave it alone.
One leader in this emerging field is Stanford chemist Carolyn Bertozzi. Last month her lab published a PNAS paper showing it’s possible to recruit natural killer cells to attack tumors by stripping a key sugar off the surface of the cancer cells. And last week two other labs reported in Nature Immunology that another cancer-specific sugar can turn macrophages into traitors that ignore tumor cells rather than attack them.
As an immunology PhD who writes about immunotherapy (mostly for Cancer Discovery, a subscription-only site for researchers), I was stunned to have heard next to nothing about sugar-based approaches before seeing a news release on Bertozzi’s PNAS paper. The Stanford PIO who wrote it told me she didn’t know of other journalists covering the paper—or the area in general. Scientists have long known that sugars play key roles in cancer, she says, but sugars are hard to work with in the lab. Unlike proteins, sugars are not encoded by genes, and there aren’t many handy tools to study and manipulate them.
But a few 2014 papers broke ground, and besides the two recent publications Bertozzi knows others in the pipeline and predicts “a burst” later this year. Plus, some companies have caught wind of these developments and started their own preclinical programs.
So the time is ripe for a feature on this up-and-coming field. I will take readers through the troubles, tenacity and recent triumphs of Bertozzi and other “sugars in cancer” pioneers—Paul Crocker at the University of Dundee; Joy Burchell at Kings College London; Stephan von Gunten at the University of Bern; and Ajit Varki at UC San Diego.
Bertozzi’s gotten recent press in The Scientist and the American Society for Biochemistry and Molecular Biology (ASBMB). But those profiles describe her life, career and social media presence whereas the SN feature would focus on the research—and not just Bertozzi’s.
I’m an experienced science journalist who’s written a two-part SNS series on superbugs, a profile of UCSF biochemist Peter Walter for HHMI Bulletin (where Cori used to work) and various biomedical stories for Scientific American. Earlier this year I wrote an SNS news piece about a PCR-based antibody assay developed by Bertozzi’s group, and since I’m in the Bay Area I can do on-site reporting at her Stanford lab.
If you’re game for a feature about sugar-based immunotherapy, I’d love to write it!