CVN & SV shared first author
We have provided in vitro and in vivo evidence for BRIP1/FANCJ acting as cooperative driver gene in neuroblastoma and showed strong up regulation of this gene during TH-MYCN driven tumor formation in mice (Vanhauwaert, this meeting). BRIP1/FANCJ is a DNA helicase implicated in unwinding of G-quadruplexes (G4s) and knock down induces replication fork stalling and epigenetic instability. G4s are secondary DNA structures, formed by stable Hoogsteen hydrogen bonding guanines in planes of 4 guanines stacked on top of each other. Several studies have demonstrated that G4 structures can cause genomic instability and are prone to particular genomic rearrangement due to the action of DNA damage tolerance pathways activated to resolve replication stalling at these G4s. Consequently, G4s pose a threat to the rapid cycling and the transcriptionally active state of neuroblastoma cells as replication forks will typically stall at G4s under conditions of replicative stress. We hypothesize that neuroblastoma cells are "replicative stress resistance" addicted. To further elucidate the molecular basis for this presumed addiction, we collected several data sets allowing to perform an integrated network analysis with final aim of identifying a G4 based gene signature reflecting dependence of neuroblastoma cells to alleviating G4 driven replicative stress. First, RNA sequencing was performed on neuroblastoma cells after knock down of BRIP1/FANCJ. Secondly, RNA sequencing was done after exposure of neuroblastoma cells to selected G4-binding ligands. Finally, in vivo drugging experiments are ongoing to provide RNA sequencing on zebrafish neuroblastomas after exposure to G4 ligands in combination with selected small molecules currently under evaluation in clinical trials. In the future, we will further integrate data mining and cross species genomics analyses for the identification of G4 marked genes critically involved in maintenance of the neuroblastoma phenotype.