Neuroblastoma (NB), an embryonic malignancy of the sympathetic nervous system, is the most common extracranial solid tumor in childhood. NB is characterized by an extreme biological and genetic heterogeneity, resulting in a wide spectrum of clinical outcomes. Despite various multimodal therapies, the overall survival of patients with high-risk NB (HR-NB) struggles to exceed 50% and is associated with a high risk of late treatment-related adverse effects. As a result, immunotherapies and radiopharmaceuticals, as well as emerging treatments focusing on targeted therapies, are being investigated. However, for some of the high-priority targets, there are currently no drugs in the clinic. Continued efforts are needed to identify new targets.
TWIST1, a transcription factor well established as an oncogene, has recently been found to be implicated in NB pathogenesis and poor prognosis. Indeed, TWIST1 has been shown to regulate a transcriptional program associated with HR-NB tumors and to be a key mediator of aggressive NB phenotypes. Several key genes dysregulated by TWIST1 in NB have been identified, forming a 489-gene TWIST1-signature. As a result, TWIST1 represents a promising therapeutic target for HR-NB. While direct targeting of TWIST1 may be challenging, its signaling pathways or key effectors may offer new therapeutic options.
The aim of this study was to identify indirect TWIST1 target genes involved in HR-NB. By refining the TWIST1-mediated gene expression signature and isolating genes correlated with high risk in non-MYCN-amplified (MNA) NB, we sought to validate potential genes as prognostic biomarkers and therapeutic targets for HR-NB.
The TWIST1-signature was reduced to 240 genes by crossing TWIST1-correlated genes in 5 cohorts of primary NB transcriptomic datasets with the list of differentially expressed genes identified in orthotopic SK-N-Be2c tumors. High expression of the resulting 240-gene signature was associated with poor prognosis and low survival. A sublist of 12 potentially promising target genes for HR-NB therapy was selected from this signature by crossing it with the TWIST1- correlated genes in both HR-NB and non-MNA subcohorts. We then analyzed the individual clinical significance and performed an extensive literature review on these 12 genes. Five of them were selected to validate their dysregulation in TWIST1-positive and TWIST1-negative NB samples at the RNA level and, for some of them, at the protein level. All selected genes appeared to be clinically relevant. DDR2, one of the selected genes, may indeed be a promising potential new therapeutic target, and LMO3, LGR5, and TEAD4 deserve further functional investigations to confirm their potential as prognostic markers and/or novel therapeutic targets. RT-qPCRs showed upregulation of PCOLCE, LMO3, DDR2, CLMP and TEAD4 by TWIST1 in the MNA samples but, except for PCOLCE, not in the non-MNA samples, suggesting that the effect of TWIST1 in HR-NB may be different depending on the MYCN status of the tumor and highlighting the need for further studies on its differential role in the MNA versus non-MNA context.
Overall, this study provides new clues for a better understanding of TWIST1 function in NB pathogenesis, paving the way for new functional studies on the molecular mechanisms underlying the tumor aggressiveness, and opening new perspectives for the treatment of HR- NB.