Eric J. Rellinger

Neuroblastoma is a devastating pediatric solid tumor that, despite significant recent advances, still accounts for nearly 15% of all childhood cancer deaths. Patients are risk stratified based on a number of features, including amplification of the MYCN oncogene, yet targeting MYCN itself has been unsuccessful to date. The complex interplay between this oncogene and its many metabolic targets has proven challenging and is only beginning to be understood in the context of pediatric tumors. It is increasingly recognized, however, that MYCN-driven metabolic rewiring and concomitant increases in biosynthetic precursors has the potential to drive many aspects of tumor development. Furthermore, emerging research suggests that improving overall therapeutic outcomes for neuroblastoma patients may well require individual metabolic profiling, allowing personalized simultaneous targeting of multiple metabolic nodes. In this review, we outline clinically relevant research involving MYCN-driven metabolic derangements, including increased glucose uptake, polyamine synthesis, glycosylation, and others, and attempt to summarize the influence of MYCN on important metabolic genes and druggable protein targets. We spotlight emerging research in glycosylation and its modulation as an often overlooked but increasingly promising therapeutic area. It is our hope that this document will provide utility for both clinicians and scientists seeking to understand how the MYCN oncogene and metabolism are critically intertwined.

MYCN-amplification is a genetic hallmark of ~40% of high-risk neuroblastomas (NBs). Altered glycosylation is a common feature of adult cancer progression, but little is known about how genetic signatures such as MYCN-amplification alter glycosylation profiles. Herein, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) revealed increased core fucosylated glycan abundance within neuroblast-rich regions of human MYCN-amplified NB tumors. GDP-mannose 4,6-dehydratase (GMDS) is responsible for the first-committed and rate-limiting step of de novo GDP-fucose synthesis. High GMDS expression was found to be associated with poor patient survival, advanced stage disease, and MYCN-amplification in human NB tumors. Chromatin immunoprecipitation and promoter reporter assays demonstrated that N-MYC directly binds and activates the GMDS promoter in NB cells. When GMDS was blocked through either genetic or pharmacological mechanisms, NBs were found to be dependent upon de novo GDP-fucose production to sustain cell surface and secreted core fucosylated glycan abundance, as well as adherence and motility. Moreover, genetic knockdown of GMDS inhibited tumor formation and progression in vivo. These critical findings identify de novo GDP-fucose production as a novel metabolic vulnerability that may be exploited in designing new treatment strategies for MYCN-amplified NBs.

MYCN-amplification is a genetic hallmark of ~ 40% of high-risk neuroblastomas (NBs). Altered glycosylation is a common feature of adult cancer progression, but little is known about how genetic signatures such as MYCN-amplification alter glycosylation profiles. Herein, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) revealed increased core fucosylated glycan abundance within human MYCN-amplified NB tumors. GDP-mannose 4,6-dehydratase (GMDS) is responsible for the first committed step of de novo GDP-fucose synthesis. High GMDS expression was found to be associated with poor patient survival, advanced stage disease, and MYCN-amplification in human NB tumors. Chromatin immunoprecipitation and promoter reporter assays demonstrated that N-MYC directly binds and activates the GMDS promoter in NB cells. When GMDS was blocked through either genetic or pharmacological mechanisms, NBs were found to be dependent upon de novo GDP-fucose production to sustain cell surface and secreted core fucosylated glycan abundance, as well as adherence and motility. Moreover, when de novo fucose synthesis was inhibited in vivo, tumor formation and progression were blocked. These critical findings identify de novo GDP-fucose production as a novel metabolic vulnerability that may be exploited in designing new treatment strategies for MYCN-amplified NBs.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in the pediatric and adolescent population, with 350 new cases diagnosed each year. While they can develop anywhere in the body, the genitourinary tract is the second most common primary location for an RMS to develop. Overall survival has improved through the increased use of protocols and multidisciplinary approaches. However, the guidelines for management continue to change as systemic and radiation therapeutics advance. Given the relative rarity of this disease compared to other non-solid childhood malignancies, healthcare providers not directly managing RMS may not be familiar with their presentation and updated management. This review aims to provide foundational knowledge of the management of RMSs with an emphasis on specific management paradigms for those arising from the genitourinary tract. The genitourinary tract is the second most common location for an RMS to develop but varies greatly in symptomology and survival depending on the organ of origin. As the clinical understanding of these tumors advances, treatment paradigms have evolved. Herein, we describe the breadth of presentations for genitourinary RMSs with diagnostic and treatment management considerations, incorporating the most recently available guidelines and societal consensus recommendations.