In a FLASH: reducing toxicity and enhancing cure for pediatric brain tumors

Although treatment advancements have increased survival rates for pediatric brain tumors, side effects remain a major issue. Recalling new information (memory), promptly completing mental tasks (processing speed), and maintaining focus (attention) are particularly affected in patients treated with radiation therapy (RT). We will address this problem by investigating FLASH, a method of delivering RT quickly, which has been shown to reduce short- and long-term neurocognitive problems in young mice compared to conventional RT. Originally, FLASH was delivered using electrons and X-rays, but these methods cannot reach deep parts of the brain where most brain tumors are located. A new technique, pencil beam scanning proton therapy, uses protons to deliver FLASH (pFLASH) to treat brain tumors. While promising, this approach cannot be translated to clinical practice because the correct dose for curing tumors and the best delivery method are still unknown. We aim to characterize the toxicity, cognitive function, and survival after p-FLASH compared to conventional RT in healthy mice and in mice with metastatic medulloblastoma and atypical teratoid/rhabdoid tumor, both of which are aggressive pediatric brain tumors. Our study will define optimal radiation doses and schedules to protect cognition and effectively treat these aggressive pediatric brain tumors with the long-term goal of translating this new technique into clinical practice.

Identify Genetic Drivers Metastasis Using an Established Zebrafish Model of High-Risk Neuroblastoma

Metastatic disease is difficult to treat in neuroblastoma (NB) and is the number one cause of death. Unfortunately, we know little about the mechanisms that control metastasis in NB due to the lack of an appropriate animal model. Patients are designated as high-risk (HR) for having MYCN-amplification or being over 18-months-of-age with metastatic disease. In addition, segmental chromosomal aberrations (SCA) are the most common genetic alteration in HR-NB, where large chromosomal regions are lost or gained disrupting 100s of genes. Determining which genes are critical to metastatic disease within a SCA is difficult, as many are passengers genes that are not important in disease pathology. The zebrafish is important in vivo model for defining the role of new genetic mutations in HR-NB. MYCN_TT zebrafish are unique NB animal model that spontaneously metastasize. Our preliminary data shows that MYCN_TT tumors evolve through copy number alterations (CNA), like HR-NB. We will perform whole genome sequencing to detect CNA in highly metastatic MYCN_TT zebrafish. Next, we will use a cross-species genomics approach to identify CNA shared in both metastatic MYCN_TT and human NB. CNAs shared between species separated by 450 million years of evolution are strong candidate drivers of metastatic disease in NB. Finally, we will test our top 5 driver CNA in human NB cell lines to see their impact on metastatic phenotypes (invasion and migration).

Precision Epigenetic Therapies for Pediatric Burkitt Lymphoma

Burkitt lymphoma is one of the fastest growing childhood cancers, yet children who relapse have very limited treatment options. This project focuses on a newly discovered weakness in Burkitt lymphoma: mutations in the BAF complex, a group of proteins that normally control how DNA is packaged and which genes are turned on or off. More than half of children with Burkitt lymphoma carry these mutations, which change how immune cells develop and make them more likely to become cancerous. We hypothesize that when these genetic changes co-occur together with chronic inflammation, such as from virus infection or even diet-related inflammation, immune cells are prone to enter a dangerous cycle of repeated growth and mutation. This sets the stage for lymphoma to form and progress. We have identified a new drug that blocks the altered BAF complex and selectively kills Burkitt lymphoma cells with these mutations, while sparing normal cells. In this project we will use advanced models and engineered pediatric lymphoma cells to learn exactly how BAF mutations and inflammation cooperate to drive cancer. We will also test whether combining BAF inhibitors with anti-inflammatory or immune-based therapies can more effectively eliminate tumors. The goal is to create precision treatments for children with Burkitt lymphoma, especially those with relapsed or high-risk disease. We aim to develop safer and more effective therapies that improve survival and quality of life for young patients.

Deciphering mutually exclusive T-ALL and neurodevelopmental mutations in the ARD domain of the ZMIZ1 coactivator

There is an urgent need to find new drugs for ETP leukemia because the usual ones don’t work. It is also a large subtype, comprising 20% of pediatric T-ALL patients. Little is known about ETP cancer since it was recently defined. When scientists try to find a cure for a cancer, a popular idea is to find a drug that blocks a specific genetic mutation. But this approach would be inefficient for ETP leukemia because each mutation is rare. To overcome this challenge, our vision is to target the cell state that is shared by all ETP cancers rather than a specific mutation. What gives an ETP cell its state of "ETP-ness"? The answer is a genetic circuit inside cells that we call the "ETP gene network". This network turns on stem cell genes. Recently, my lab reported that the ZMIZ1 protein activates this network. We examined a part of ZMIZ1 called the ARD that is mutated in T-ALL and a neurodevelopmental disorder. Our initial work modeling these mutations suggests that the mutant ARD protects ZMIZ1 from being degraded and helps it rope together several control centers in the ETP gene network to construct "super control centers" with extraordinarily high activity. In our B+ project, we will learn how these mutations protect ZMIZ1 in order to find ways to overcome this protection and degrade ZMIZ1. Importantly, ZMIZ1 is not essential for health. Therefore, drugs that degrade ZMIZ1 might be a new kind of therapy that avoids the toxic effects of chemotherapy and help all ETP patients.

Development and Validation of Patient-Reported Outcome Measures for Pediatric Cancer Surgery

The diagnosis of cancer in a child or adolescent often requires chemotherapy and surgical procedures for treatment. The best patient outcomes cannot be achieved simply by looking at traditional medical history, lab tests, and imaging findings. In previous studies, families of children that have received cancer surgery have told us that they wished their care providers communicated the options for surgery thoroughly and listened more carefully. Understanding a child’s quality of life and the impact that the treatment of a childhood cancer has on the patient and family is essential to the obtain the best outcomes from surgery and overall treatment. When children undergo surgery for cancer, it's not just the medical outcomes that matter—how they feel and recover after surgery is equally important. This project aims to create a system that listens to what young patients and their families have to say about their experiences before and after surgery. By working directly with patients, we can make better decisions about their care, helping them recover more quickly and feel better overall. This project will support efforts to develop a tool that doctors can use to gather patient and family feedback, making sure every child receives care tailored to their unique needs and experiences. This will help us understand where there may be problems in the patient’s treatment journey and allow health care professionals to fix the issues before they impact long-term outcomes of treatment.

Linking the Gut Microbiome to Chemotherapy Toxicity in Pediatric ALL

Childhood acute lymphoblastic leukemia (ALL) is the most common type of cancer in children. While treatments have improved survival rates, many children experience severe adverse effects from chemotherapy, such as life-threatening infections or damage to vital organs. Current methods rely on trial-and-error approaches, while identifying which children are at higher risk for these complications before treatment starts constitutes a significant unmet clinical challenge. In this project, we will harness the gut microbiome, the community of bacteria inhabiting our gut, to predict which children are more likely to experience severe treatment-realted side effects. Together with a leading tertiary cancer center, we will collect host and microbiome data from 250 children newly diagnosed with ALL. Using AI, we will analyze the data to find patterns linked to adverse events and develop personalized AI-based prediction models for leukemia-related adverse effects. Our initial results show that utilization of personalized microbiome data from children prior to the beginning of chemotherapy, and its analysis using AI, enables robust predictability of a variety of chemotherapy-induced adverse events. To understand if and how the gut microbiome contributes to chemotherapy-induced adverse effects in ALL, we will transplant gut bacteria from patients impacted by chemotherapy-induced toxicities into germ-free mice and mechanistically decode the effect of gut commensals on these adverse effects.

Mapping Mitochondrial-localized mRNA Translational Rewiring in Radiation-resistant Pediatric DIPG

Diffuse intrinsic pontine glioma (DIPG) remains one of the most devastating pediatric cancers, with a median survival of less than one year and no effective therapies beyond radiotherapy. Despite decades of effort, chemotherapeutic interventions have failed to extend survival, in part due to intrinsic and acquired resistance to radiation. The urgent unmet clinical need for novel therapeutic strategies underscores the importance of uncovering fundamental biological mechanisms that enable DIPG survival under therapeutic stress. Mitochondria have emerged as central players in therapy resistance across many tumor types, and accumulating evidence suggests that DIPG is particularly dependent on mitochondrial oxidative phosphorylation (OXPHOS) for growth and survival. In particular, DIPG cells exhibit heightened OXPHOS activity and maintain metabolic flexibility that supports survival following radiation. Disruption of mitochondrial function can radiosensitize glioma cells, yet these approaches have shown limited translation to the clinic, in part because the systems-level rewiring of mitochondrial gene expression and local translation in DIPG remains poorly understood. This proposal addresses that gap by applying APEX-seq (Fazal et al., Cell 2019), an RNA proximity labeling approach we developed, to map the landscape of mitochondrial RNA localization and local translation in DIPG cells pre- and postradiotherapy.

Dissecting Ewing Sarcoma On-Chip for Better Therapeutics

Ewing sarcoma is a rare and aggressive cancer that primarily affects the bones or soft tissues of children and young adults. For patients whose cancer has spread or returned, survival rates remain below 30% at five years. Current treatments like chemotherapy and radiation often fail in these high-risk cases. While new approaches like CAR T cell therapy have transformed care for some cancers, they’ve been ineffective in Ewing sarcoma, largely due to a poor understanding of how the tumor interacts with its surroundings, especially the bone marrow environment that supports tumor growth and immune evasion. To address this, we developed a 3D model called Sarcoma-on-a-Chip that mimics the human bone marrow. This miniaturized living system includes tumor cells along with immune cells, blood vessels, and bone-forming support cells. It enables us to study how Ewing sarcoma behaves in a realistic, human-like setting. Using this platform, we will 1)identify genes that help the tumor survive in the bone marrow using CRISPR gene-editing tools, and 2) investigate how the tumor suppresses immune responses. Early findings show that Ewing sarcoma disrupts immune cell function and creates an immune-suppressive environment. This project will uncover new vulnerabilities in Ewing sarcoma and guide the development of more effective therapies, with the ultimate goal of improving outcomes for children with this devastating cancer.

Tumor-specific PROTAC development as a new therapeutic approach for osteosarcoma

This proposal addresses a need for the development of a safe and new therapeutic approach for treating an aggressive cancer, osteosarcoma. Osteosarcoma is one of the most prevalent bone cancers in children and young adults, with a 30% 5-year survival rate when pulmonary metastases are detected. Current standard of care for localized osteosarcoma includes surgery and chemotherapy, which can achieve long-term survival in only 60% of cases. No new approaches have been developed since the 1980s. To address this gap in development, we are developing a new therapeutic strategy against two well-established targets in osteosarcoma, BRD4 and the WEE1 kinase. While inhibitors have been developed, a limitation to inhibiting these proteins is the significant dose-limiting toxicities that patients experience. To overcome these toxic side effects, we are developing first-in-class tissue-specific molecules capable of degrading either the BRD4 protein or the WEE1 kinase in tumor tissue while sparing healthy cells. Our team has significant expertise in therapeutic development for both proteins and has already developed preliminary data supporting our ability to degrade the BRD4 protein in osteosarcoma cells and downregulate the cancer oncogene c-MYC, which is dysregulated in almost 50% of all cancers. These findings can also be extended to treating additional adult and pediatric cancers, including neuroblastoma. We anticipate this new approach will be more efficacious than existing inhibitors.

Dissecting CBFA2T3-GLIS2 Fusion-Driven Leukemogenesis and Therapeutic Resistance

Some types of childhood leukemia begin before birth, when early blood cells develop harmful genetic changes. One especially aggressive form, called CBFA2T3-GLIS2 acute megakaryocytic leukemia, is difficult to treat because it often resists chemotherapy and comes back after treatment. This project aims to understand how this leukemia starts and why it returns. Dr. Hadland’s team will use advanced lab models to mimic how the disease originates in early blood cells and transforms over time to frank leukemia. By studying these models, they hope to discover how leukemia cells grow, survive treatment, and change over time. The research has two main goals: first, to find ways to stop leukemia before it becomes dangerous, and second, to identify and eliminate the cells that survive treatment and cause relapse. The team will use powerful tools to track individual cells and uncover weak points that could be targeted with new therapies. This work could lead to better treatments and even ways to prevent leukemia in children who are at risk. In the future, it may be possible to detect genetic changes associated with these leukemias at birth and treat children early—before the disease ever develops.

GLUL as a novel therapeutic target in pediatric T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy that prominently affects kids. Despite recent advances, 20% of children still relapse and the prognosis of these cases remains extremely poor, highlighting the need to discover novel targeted therapeutic approaches. We previously demonstrated the therapeutic effects of targeting metabolic routes in leukemia. In this setting, our latest results have identified a novel metabolic regulator (GLUL) as an important player in T-ALL. Indeed, with genetic tricks by which we can remove GLUL from leukemias in mice, we have observed very significant therapeutic effects, curing 50% of the mice. However, there is nothing known about GLUL in T-ALL. Thus, here we will comprehensively dissect the effects of targeting GLUL in T-ALL using state-of-the-art techniques in human T-ALL cell lines, mouse primary leukemias in vivo and patient-derived xenografts. Integration of mouse and human data will allow us to understand how T-ALL cells respond to GLUL inhibition. Our results will help us design new combinations with current treatments that will result in stronger antileukemic effects and reduced relapses in the future.

Development of a Measure of Social Connectedness for Survivors of Pediatric Brain Tumors

Children treated for a brain tumor have significant problems with social connectedness that begin early in survivorship, persist through adulthood, and cause psychological and medical morbidities. Despite the significance of this issue, these youth are not routinely identified during clinical care due to a lack of validated measures evaluating social connectedness in this population. The constellation of social difficulties and factors contributing to them are unique to this population, increasing the need for a population-specific measure. Such a measure could be integrated into routine clinical care to identify those with social difficulties at an earlier stage to facilitate services to promote social connectedness. The objectives of this proposal are to develop and validate a measure of social connectedness difficulties in pediatric brain tumor survivors. An Advisory Board, consisting of pediatric neurooncology clinicians, experts in social challenges in other populations, and parents of pediatric brain tumor survivors will offer feedback at each phase. In Phase 1, we will develop an item bank for the measure. In Phase 2, we will evaluate the psychometric properties and factor structure of the measure in a sample of survivors recruited from the Children's Hospital of Philadelphia. In Phase 3, we will refine the measure based on Phase 2 data and Advisory Board feedback. This work will establish a measure specific to survivors and suitable for clinical use.

Targeting ALT-Associated Vulnerabilities in Pediatric High-Grade Glioma

Pediatric high-grade gliomas are among the most aggressive childhood brain cancers, with few effective treatments and poor survival. Many of these tumors carry mutations in a gene called ATRX, which normally helps maintain chromosome ends, or telomeres. When ATRX is lost, the tumor cells switch on an alternative system called ALT (alternative lengthening of telomeres) to keep dividing. While this allows the cancer to grow, it also creates a weakness: these cells experience constant damage at their telomeres and must rely on backup repair pathways to survive. We discovered that ATRX-deficient, ALT-positive gliomas are especially dependent on a protein called FANCM, which helps repair damaged telomeres. When FANCM is blocked, ALT-driven tumor cells die, but healthy cells are largely unaffected. This makes FANCM a highly promising target for therapy. We have already identified small molecules that can mark FANCM for destruction inside tumor cells, a strategy known as targeted protein degradation. In this project, we will refine these FANCM degraders and test them in cell and mouse models of pediatric glioma. Our goal is to determine whether this approach can slow tumor growth and extend survival, without harming normal tissues. By exploiting a unique weakness created by ATRX loss, this research introduces a new treatment strategy for these otherwise “undruggable” pediatric brain tumors, with the potential to improve outcomes for children facing this devastating disease.

Inhibition of the RNA translation factor, eIF4E, as a novel treatment strategy in Ewing Sarcoma

Ewing sarcoma is a rare, aggressive bone cancer mainly affecting children and young adults. Patients with metastatic or recurrent forms face poor prognoses, with 5-year survival rates dropping to 15-30 percent. Treatment involves aggressive chemotherapy and clinical trials exploring innovative therapies, though recent trials have not notably improved outcomes. Current research focuses on the cancer’s biological foundations, specifically the EWSR1-FLI1 fusion protein, which hijacks normal RNA processes to propagate the cancer. Our lab targets RNA translation, the process of making proteins from RNA, as a potential treatment avenue in pediatric cancers like Ewing sarcoma. Our preliminary data show that Ewing sarcoma cells are particularly sensitive to drugs impeding RNA translation. Key components of RNA processing are abundant in these cancer cells, presenting an opportunity for novel therapies. This proposal hypothesizes that blocking EIF4E, a critical component of RNA translation, could effectively treat Ewing sarcoma. Utilizing resources at the University of Michigan, we aim to test both existing and new drugs targeting EIF4E. Our research will involve assessing the efficacy of these drugs on Ewing sarcoma models and tumors in mice, as well as exploring the molecular reasons behind the cancer's susceptibility. This work seeks to deepen our understanding of Ewing sarcoma's cancer biology while identifying small molecule inhibitors suitable for clinical development.

Enhancing GD2-CAR NKT anti-tumor efficacy against neuroblastoma by targeting BLIMP1

My research focuses on training a special type of immune cell called a natural killer T cell (NKT) to recognize and kill neuroblastoma (NB) tumor cells without causing the toxic side effects associated with traditional chemotherapy. NB is the most common and hardest to treat pediatric solid tumor outside of the brain. We initiated the first trial in humans to treat patients with their own NKT cells engineered to express a chimeric antigen receptor (CAR) that targets NB cells and spares healthy cells. While the therapy was safe and generated some clinical responses, most did not last and the NKT cells did not persist long-term in the blood. Findings from recent research in my group showed that a protein called BLIMP1 impacts how long CAR-NKTs persist in the body and that when BLIMP1 expression is lower, CAR-NKTs tend to persist longer. However, we also found that when we completely remove BLIMP1 expression through genetic “knock-out,” CAR-NKTs become less effective at killing NB cells. Thus, my current research aims to use two unique strategies with the goal of improving CAR-NKT persistence without compromising their ability to kill NB cells.