Modified FDA Drug Blocks Pediatric Brain Tumor Relapse

Summary: A precision pediatric oncology study unmasked a dual-targeting therapeutic strategy to stop the relapse of medulloblastoma, the most common malignant childhood brain tumor. While initial treatment survival rates are encouraging, roughly 30% of patients experience a devastating recurrence driven by a highly resistant subset of slow-dividing, self-renewing tumor cells.

The research demonstrates that an FDA-approved compound, pyrvinium, can successfully halt this relapse mechanism. By activating a critical protein controller, the therapy simultaneously shuts down two independent survival pathways, effectively trapping the tumor cells and preventing them from engineering a recurrence.

Key Facts

• The Recurrence Crisis: Medulloblastoma stands as the most common malignant pediatric brain tumor. While frontline therapies are initially successful at shrinking the primary mass, the cancer returns in approximately 30% of young patients, leading to a relapse where long-term survival outcomes drop close to zero.
• Evading the Silver Bullet: The root of cancer relapse hides within a small, powerful sub-population of tumor cells capable of self-renewal. Because these cells divide much slower than standard tumor mass, traditional therapies miss them entirely, leaving a hidden reservoir primed to drive aggressive regrowth.
• The Dual-Pathway Escape Route: Cancer cells are highly efficient at circumventing single-target drugs. To cut off their escape routes, the MUSC Hollings team targeted a master protein called CK1alpha, which simultaneously regulates two separate, vital cancer-signaling lines: the GLI pathway (which drives active tumor growth) and the WNT pathway (which fuels slow-burning cellular self-renewal).
• The Pyrvinium Supercharger: Investigators deployed pyrvinium, an FDA-approved drug with emerging utility in oncology. By activating the CK1alpha protein, pyrvinium successfully suppressed GLI-driven tumor expansion while completely blocking WNT-driven self-renewal—outperforming alternative single-target approaches in preclinical models by significantly delaying and reducing overall relapse risks.
• Overcoming the Blood-Brain Barrier: A major physiological hurdle is that standard pyrvinium cannot easily cross the protective blood-brain barrier. To solve this clinical delivery challenge, the research team successfully engineered and tested a modified, brain-penetrating version of the drug that successfully reaches brain tissue with highly promising results.
• Protecting Developing Minds: Shifting to targeted molecular therapies minimizes the severe, long-term developmental side effects and future cancer risks caused when adult chemotherapy protocols are bluntly adapted for young, growing children.

Source: Medical University of South Carolina

Stopping cancer from coming back is the goal of new research from MUSC Hollings Cancer Center, where scientists are targeting cells that fuel the return of an aggressive pediatric brain tumor.

For most children diagnosed with medulloblastoma, the most common malignant pediatric brain tumor, survival rates are encouraging. But for a subset, remission is not the end of the story. Roughly 30% of patients will see their cancer return, and once it does, outcomes are often devastating.

“Once the tumor comes back, long-term survival is close to zero,” said Jezabel Rodriguez Blanco, Ph.D., who holds dual appointments at Hollings and the Darby Children’s Research Institute at MUSC.“That’s the group we’re trying to help with this research.”

In a study published in Cell Death & Disease, researchers led by Blanco identified a potential way to reduce relapse in medulloblastoma by targeting the tumor cells most likely to survive treatment and drive regrowth.

Going after the root of relapse

The research centers on a small but powerful group of tumor cells that can self-renew. Unlike the rest of the tumor, these cells divide more slowly and rely on different biological pathways, allowing them to evade standard treatments and promote new tumor growth.

“These cells are resistant to therapy,” Blanco said. “They don’t divide as much, so many treatments miss them. But they’re the ones that enable the tumor to come back.”

That dynamic helps to explain a persistent challenge in medulloblastoma care. Treatments can initially shrink tumors, only for the cancer to return – often more aggressively.

To tackle this problem, the team tested an expanded strategy. Instead of targeting only tumor growth, they also set out to disrupt the signals that sustain these relapse-driving cells.

They focused on a protein called CK1α that regulates two key cancer-signaling pathways:

• Glioma-associated oncogene homolog (GLI), linked to tumor growth.
• Wingless-related integration site (WNT), which supports tumor self-renewal.

This work builds on earlier research by Blanco, showing that GLI inhibition can slow tumor growth and reduce the risk of relapse. In this new study, the researchers tested pyrvinium, a Food and Drug Administration-approved drug with emerging potential in cancer research because of its ability to block GLI.

By activating CK1α, pyrvinium suppressed GLI-signaling pathways and, therefore, attenuated tumor growth. Pyrvinium also targeted WNT-driven self-renewal, conferring an advantage over other GLI-targeting approaches. In preclinical models, pyrvinium blocked medulloblastoma self-renewal, extending the time to relapse and reducing the overall risk of relapse.

That dual targeting may be what makes the approach more effective.

“Cancer cells are very good at escaping when you hit just one pathway,” Blanco explained. “If you hit both, you have a better chance of preventing that escape.”

In comparison, treatments targeting only one pathway often shrink tumors at first – but miss the cells that drive regrowth – helping to explain why they have not delivered lasting results for some patients. The new approach may offer a workaround by hitting the same biology through a different mechanism.

Promising – but early – progress

Despite encouraging results, Blanco stressed that the work is still in early stages.

“This is working very well in our models,” she said. “But there’s a long path before it becomes a treatment for patients.”

One major hurdle is delivery. Pyrvinium does not readily cross the blood-brain barrier, limiting its direct use for brain tumors. To address that, the team tested a modified version of the drug that can reach the brain, with promising results in preclinical models. The next step will be to develop and refine the compound to ensure it is effective and safe for use in children.

For young patients with medulloblastoma, the impact extends beyond survival to life after treatment. Current therapies can leave lasting effects, from developmental challenges to increased risk of future cancers.

“We’re often adapting adult cancer treatments for children. But pediatric tumors are different, and the long-term side effects can be severe,” Blanco said. “Especially for families whose children relapse, the stakes couldn’t be higher.”

By shifting focus to the cells that drive recurrence, the research points to a new direction –one aimed not just at shrinking tumors but at stopping them from returning.

“This is about going after the root of relapse,” she said. “If we can do that, we have a real chance to change outcomes for these kids.”

Key Questions Answered:

Editorial Notes:

• This article was edited by a Neuroscience News editor.
• Journal paper reviewed in full.
• Additional context added by our staff.

About this brain cancer research news

Author: Leslie Cantu
Source: Medical University of South Carolina
Contact: Leslie Cantu – Medical University of South Carolina
Image: The image is credited to Neuroscience News

Original Research: Open access.
“CK1α agonists attenuate medulloblastoma stemness and relapse risk” by Kendell Peterson, Maria Turos-Cabal, Pritika Shahani, April D. Salvador, Marzena Swiderska-Syn, Giulia D. S. Ferretti, Carlos Alfaro-Quinde, Valentin Kliebe, Laura Finelli, Ashley J. Howell, Megan E. Vieira, Isabel Palomo-Caturla, Dennis L. Fei, Daniel T. Wynn, Vanesa Martin, Thibaut Barnoud & Jezabel Rodriguez-Blanco. Cell Death and Disease
DOI:10.1038/s41419-026-08762-6

Abstract

CK1α agonists attenuate medulloblastoma stemness and relapse risk

While outcomes for most children with medulloblastoma (MB) are relatively favorable, those in the Sonic Hedgehog (SHH) subgroup with Tumor protein P53 (TP53) mutations—known as the SHHα subtype—face a much poorer prognosis. SHHα patients relapse more frequently and rapidly, underscoring the need for therapies that prevent recurrence.

We recently identified a non-canonical Gli-driven Sox2⁺ cell population that promotes relapse in SHH MB. However, few Gli-targeting strategies have shown clinical promise to date. One translational Gli inhibitor is pyrvinium, an FDA-approved compound known to destabilize Gli through increasing Casein kinase 1α (CK1α) activity.

In this study, we tested whether pyrvinium and a brain-permeable derivative, SSTC3, affect stemness and relapse risk in mouse and human-derived SHHα MB models.

We found that pyrvinium suppresses the Gli-driven proliferation of Sox2⁺ cells. Unlike other SHH/Gli-targeting approaches, pyrvinium also impaired MB self-renewal by depleting Cluster of Differentiation 15 (CD15)⁺ cells. Mechanistic studies revealed that CD15⁺ cell self-renewal is WNT-dependent and driven by the loss of p53/microRNA-34a-mediated repression of WNT signaling.

Remarkably, pyrvinium and SSTC3 reduced Sox2⁺, CD15⁺, and dual Sox2/CD15-labeled populations in mouse and patient-derived SHHα models. Consistent with their ability to diminish tumor stemness, pyrvinium also impaired primary and secondary tumor engraftment.

Our findings show that CK1α agonists regulate stemness in SHHα MB, establishing CK1α as a therapeutically relevant vulnerability. While pyrvinium itself is not an ideal clinical candidate, these data support the development of second-generation brain-penetrant CK1α-targeting derivatives.