Serine-Free Diet Shows Promise in Slowing Glioblastoma Growth and Enhancing Treatment Response
核心洞察
University of Michigan researchers discovered that removing the amino acid serine from the diet can slow brain tumor (搜索) growth and make existing treatments more effective in both mouse models and human patients.
The study published in Nature reveals that glioblastoma (搜索) cells rewire glucose metabolism to fuel growth, relying on blood-derived serine while healthy brain tissue can produce its own serine.
When combined with standard chemoradiation therapy, the serine-restricted diet extended survival in mice by forcing tumor cells to redirect glucose away from DNA (搜索) repair mechanisms.
University of Michigan researchers have identified a promising dietary intervention that could transform treatment approaches for glioblastoma (搜索), the most deadly form of brain cancer (搜索). Published in the journal Nature in September, the study demonstrates that removing the amino acid serine from the diet can slow tumor growth and enhance the effectiveness of standard cancer therapies.
The research, led by Dr. Dan Wahl, associate professor of radiation oncology, and neurosurgeon Dr. Wajd Al-Holou, represents the first major advancement in glioblastoma (搜索) treatment since temozolomide was introduced in 2005. The study combined laboratory research with clinical practice, analyzing tissue from eight patients undergoing brain tumor (搜索) surgery alongside extensive mouse model experiments.
Metabolic Rewiring in Brain Tumors
The research revealed fundamental differences in how healthy brain tissue and glioblastoma (搜索) cells process glucose. Healthy brain cells use glucose for essential functions like respiration and convert it into serine, a key amino acid needed for neurotransmitter production. In contrast, tumor cells redirect glucose metabolism toward producing nucleotides—the building blocks of DNA (搜索)—to fuel their rapid replication.
"Healthy cells in the brain need fuel to maintain their extensive list of functions, like electrical signaling and the release of chemical messengers. Cancer cells dispose of these normal processes as they rewire to become 'professional dividing cells,'" explained study co-author Costas Lyssiotis, a professor of oncology at the University of Michigan.
Critically, the study found that while healthy brain tissue can produce its own serine, glioblastoma (搜索) cells cannot. Instead, tumor cells must scavenge serine from the bloodstream and surrounding tissues to support their growth.
Dietary Intervention Strategy
The research team exploited this metabolic vulnerability by placing mice with human cancer cell transplants on a serine-free diet. This dietary restriction forced tumor cells to redirect their glucose metabolism back toward serine production, dramatically reducing their ability to synthesize nucleotides needed for DNA (搜索) repair.
"We put them on diets that didn't have any of this amino acid serine," Wahl said. "It had protein, just no serine, and that slowed down the tumor growth in the mice, in many of the mouse models we used, and made our normal treatments like radiation and chemotherapy work better."
The combination of serine restriction with standard chemoradiation therapy extended survival in mice compared to chemoradiation alone. This approach makes tumor cells more vulnerable to DNA (搜索)-damaging therapies by limiting their repair capabilities.
Clinical Translation Challenges
Implementing serine restriction in human patients presents significant challenges, as Al-Holou noted: "Unfortunately, (serine is) essentially found in every protein source out there." The research team is partnering with a company to develop specialized diets that could remove serine while maintaining adequate nutrition.
Lyssiotis suggested that human implementation could potentially involve "a low-protein diet supplemented with serine-free protein shakes" to achieve the necessary serine restriction.
Advanced Metabolic Analysis
The study employed sophisticated isotope tracing techniques, infusing patients with tagged glucose before surgery to track metabolic pathways in real-time. This approach allowed researchers to distinguish between tumors that produce serine from glucose versus those that rely on environmental serine uptake.
"Part of what we're excited about is that this isotope tracing protocol can tell us which tumors are making serine from glucose and which tumors are taking serine up from the environment," Wahl explained.
Rackham student Baharan Meghdadi, a co-author of the study, developed statistical models to predict how glioblastoma (搜索) cells rewire nutrient pathways and how these changes impact treatment response.
Expanding Research Scope
While the current study focused on glioblastoma (搜索), the research team is already investigating applications for other brain tumor (搜索) types. Of the eight human patients studied, two had different forms of brain tumors, leading to expanded research into pediatric brain cancers and slower-growing tumors with different molecular genetics.
"Now we are purposefully studying other types of brain cancer (搜索) with this technique—some slower-growing tumors, some tumors with other types of molecular genetics, some pediatric brain cancers," Wahl said.
Timeline for Clinical Trials
Wahl anticipates beginning follow-up clinical studies in human patients "later this year or early next year." However, he acknowledged the challenges of implementing dietary restrictions alongside intensive cancer treatment protocols.
"Going through cancer treatment is hard. We're asking people to come up for radiation every day, to take chemotherapy. I think asking someone to also follow a prescribed diet could be tricky," he noted.
The research represents a collaborative effort across multiple departments at Michigan Medicine, the College of Engineering, and external institutions. Al-Holou emphasized that "the lack of major advancements in brain tumor (搜索) research has been because a lot of people are kind of working in silos on their own."
Lyssiotis noted that the metabolic analysis has identified additional dietary modifications that could be explored in future work, suggesting that serine restriction represents "just the tip of the iceberg" for metabolic-based cancer therapies.