A new understanding of how normal brain development can be hijacked to fuel aggressive childhood tumors is emerging from research led by scientists at Baylor College of Medicine, St. Jude Children’s Research Hospital and Texas Children’s Hospital. The findings, published in the journal Nature, pinpoint a mechanism driving the growth of pediatric supratentorial ependymoma (EPN), the third most common malignant brain tumor in children. This discovery offers potential new avenues for treatment, particularly for these often chemo-resistant cancers.
For years, researchers have known that pediatric brain tumors often arise during critical stages of brain development. However, the precise steps that transform healthy, developing brain cells into cancerous ones have remained largely elusive. This new work suggests that a specific genetic anomaly doesn’t *initiate* the cancerous process by directly altering DNA, but rather by exploiting the natural openness of DNA during rapid cell division, a hallmark of early brain growth. Understanding this process is crucial for developing more targeted therapies for pediatric brain tumors.
Unlocking the Mystery of ZR Fusion-Positive Ependymomas
The research focused on a subtype of ependymoma known as ZFTA-RELA (ZR) fusion-positive ependymoma. These tumors predominantly affect young children and are characterized by a fusion between the ZFTA and RELA genes. This fusion creates an abnormal protein that activates genes promoting cancer development. What puzzled scientists was why this fusion protein only caused tumors in early childhood and specifically within the brain cortex – the outer layer of the brain responsible for higher-level cognitive functions.
“We reasoned that the answer might lie in the developmental plan of the brain,” explained Alisha Kardian, the study’s first author and a graduate student in the Cancer and Cell Biology Graduate Program at Baylor College of Medicine. During fetal development and early infancy, stem-like cells rapidly divide to generate the diverse array of brain cells, including neurons and glial cells, which support and protect neurons. This rapid division necessitates a more accessible DNA structure, allowing genes to be readily expressed.
Normally, as these stem cells mature, their DNA condenses, restricting access to genes and stabilizing cell identity. However, the researchers found that the ZR fusion protein doesn’t *cause* this DNA to open. instead, it takes advantage of the already open DNA structure present in these rapidly dividing cells. It then interacts with the genetic material, altering gene expression in ways that promote tumor formation. This is a critical distinction, as it suggests that the timing and location of tumor development are dictated by the brain’s natural developmental processes.
A ‘Founder’ Clone and the Immature State of Tumor Cells
Further investigation revealed that once activated by the ZR fusion protein, a single, dominant cancer cell – a “founder” clone – emerges and drives the growth of the tumor. This clone doesn’t simply replicate itself; it creates a heterogeneous tumor, meaning the tumor cells are diverse, yet they all share a common characteristic: they remain locked in an immature state, partially mimicking normal brain development but failing to fully mature.
“We found that these tumors partially mimic normal brain development, but become arrested in an immature state,” said Dr. Stephen Mack, co-corresponding author and associate member in the Department of Developmental Neurobiology at St. Jude Children’s Research Hospital. “This suggests that the tumor cells are still reliant on the developmental programs that were active during early brain formation.”
Implications for Future Therapies
The implications of this research are significant for the development of new therapies. “Understanding these developmental vulnerabilities opens the door to new therapeutic approaches aimed at pushing tumor cells toward full differentiation or targeting the early progenitor population that fuels tumor growth,” explained Dr. Benjamin Deneen, professor and Dr. Russell J. And Marian K. Blattner Chair in the Department of Neurosurgery at Baylor College of Medicine, and director of the Center for Cancer Neuroscience. Essentially, researchers may be able to exploit the tumor’s reliance on developmental pathways to force the cancer cells to mature and lose their malignant properties, or to specifically target the immature progenitor cells that drive tumor expansion.
This research builds on a growing understanding of the link between cancer and normal developmental processes. While the focus here is on ependymoma, the principles uncovered could potentially inform the treatment of other cancers that arise during development. The team’s findings highlight the importance of studying the intricate interplay between genetics and development in the fight against childhood cancers.
The researchers are now focused on identifying specific targets within these developmental pathways that can be exploited for therapeutic intervention. Further studies are needed to translate these findings into clinical trials and improved outcomes for children diagnosed with ZR fusion-positive ependymoma. The study’s findings are available in full in Nature.
Disclaimer: This article provides information for general knowledge and informational purposes only, and does not constitute medical advice. We see essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
If you or someone you know is affected by pediatric cancer, resources are available. The American Childhood Cancer Organization offers support and information at https://www.acco.org/.
This groundbreaking research offers a beacon of hope for families facing the challenges of pediatric brain tumors. The next steps involve rigorous preclinical testing of potential therapies and, clinical trials to assess their safety and efficacy. Share this article to raise awareness and support ongoing research into childhood cancers.
