Diffuse midline glioma is an aggressive pediatric brain cancer that infiltrates the brainstem, a critical region regulating vital functions such as breathing, heartbeat, and swallowing.
Nearly all pediatric patients diagnosed with this disease succumb to it within a single year, as conventional treatments struggle to halt its relentless progression without inflicting severe damage on surrounding healthy neural tissue.
Engineered Cells Target Proteins and Persist for 70 Days
- Targeted Activation: The engineered cells remain dormant until they encounter a specific brain protein, preventing off-target damage elsewhere in the body.
- Lasting Surveillance: The modified immune cells persist for more than 70 days, actively patrolling and successfully rejecting newly introduced tumor cells.
- Human Trials Ahead: Backed by preclinical data published in Science Translational Medicine, researchers are preparing for patient trials at UCSF Health.
Engineering a Molecular Switch for Brain Cancer
Traditional chimeric antigen receptor T-cell therapies program a patient’s immune cells to hunt specific proteins found on tumors. However, these conventional treatments have historically struggled against brain tumors like glioblastoma and diffuse midline glioma. To overcome this hurdle, UC San Francisco researchers Hideho Okada and Wendell Lim previously developed a two-step molecular sensing system known as synNotch.
In 2021, their earlier iteration, E-SYNC, targeted a mutant protein called EGFRvIII in glioblastoma. Yet, because only about 20% of patients express that specific mutation—and because tumors can lose the protein during treatment—scientists needed a more reliable activation signal.
The team identified brevican, a protein distributed widely throughout the brain, as a dependable trigger. They redesigned the synNotch system so that the engineered T cells, termed B-SYNC CAR-T, only switch on their cancer-fighting machinery when they encounter brevican. Once activated within the neural environment, these cells hunt down tumor targets such as EphA2 and IL13Rα2, even if the cancer cells lack the original mutation.
“By limiting B-SYNC’s CAR expression to when and where it matters — in the brain — we saw consistent, total shutdown of DMG tumors in the lab,” said Hideho Okada, MD, PhD, a professor of Neurological Surgery at UCSF and co-corresponding author of the study published October 28 in Science Translational Medicine, ScienceDaily reported.
Direct Delivery Clears Tumor Cells
To test the efficacy of this approach, postdoctoral researcher Senthilnath Lakshmanachetty administered B-SYNC cells intravenously to mice implanted with human diffuse midline glioma cells. While intravenous delivery allowed some cells to cross into the brain and trigger the targeted receptors, cells circulating elsewhere in the body remained inactive.
Seeking a more potent delivery method, researchers administered the therapy directly into the fluid-filled ventricles of the brain via intracerebroventricular injection. In two separate mouse models, this direct delivery completely cleared the tumors in every test subject, whereas conventional CAR-T cells failed to control the disease.
Beyond destroying existing growths, the treatment provided durable protection against recurrence. Nearly seven weeks post-treatment, researchers introduced a new batch of cancer cells, and every treated mouse successfully rejected them. “We didn’t expect B-SYNC CAR-T cells to necessarily persist,” Lakshmanachetty told ScienceDaily.
“But they are still patrolling for cancer over 70 days out — and they’re still very functional.” While scientists suspect that restricting early activation helps prevent T-cell exhaustion—a state where immune cells lose their potency due to prolonged over-activation—the exact mechanism behind this enhanced potency remains under investigation.
| Therapy Approach | Delivery Method | Efficacy in Mouse Models | Immune Persistence |
|---|---|---|---|
| Conventional CAR-T | Standard Infusion | Unable to control tumors | Prone to rapid exhaustion |
| B-SYNC CAR-T | Intravenous (IV) | Targeted activation in brain | Maintained functionality |
| B-SYNC CAR-T | Intracerebroventricular (ICV) | Total elimination in every mouse tested | Exceeded 70 days |
Preparing for UCSF Health Clinical Trials
After successful laboratory results, researchers are collaborating with UCSF cancer specialists to begin human testing of the therapy. The upcoming clinical trials will utilize each patient’s own T cells, which will be genetically modified in a laboratory to carry the B-SYNC architecture.
The trial will be led by UCSF physicians Marie Jaeger-Krause, MD, and Sabine Mueller, MD, PhD. To facilitate repeated dosing without requiring multiple invasive surgeries, surgical teams plan to implant a shunt connecting the brain’s ventricles to a subcutaneous reservoir beneath the scalp.
“Diffuse midline glioma is a heartbreaking diagnosis for patients and their families,” said Sabine Mueller, director of the UCSF Pediatric Brain Tumor Center and professor of Neurology, Neurosurgery, and Pediatrics. “This preclinical data is very promising. Mice with DMG are being cured, and we are incredibly excited to bring this therapy to the children and young adults we care for. This is exactly the kind of innovative approach they deserve.”
Independent clinical observers emphasize that while the laboratory data generated by the UCSF team and supported by investigations from outlets like Newsweek represents a major advance, safety and efficacy in human patients must still be established through formal clinical evaluation.
Consult Specialists Regarding Experimental Therapy and Symptoms
Because B-SYNC CAR-T remains an experimental therapy tested exclusively in animal models, it is not currently available for general clinical administration. Patients diagnosed with diffuse midline glioma or glioblastoma must consult neuro-oncology specialists to discuss standard-of-care options, ongoing clinical trial eligibility, and institutional enrollment criteria. Individuals experiencing persistent neurological deficits, sudden severe headaches, cranial nerve palsies, or balance disturbances should seek immediate evaluation by a qualified medical professional.
References
- Science Translational Medicine: SynNotch-regulated CAR-T cells targeting brain-specific proteins
- Newsweek Coverage: Scientists Wipe Out Deadly Childhood Brain Tumors in Every Mouse Tested
Disclaimer: This article is intended for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions regarding a medical condition.
