Funding outcome

Neuroblastoma accounts for ~6% of all childhood cancers as well as 15% of children deaths due to cancer. The DEAD Box 1 (DDX1) gene, encoding an RNA binding protein, is co-amplified with the oncogene MYCN in three childhood cancers including neuroblastoma, retinoblastoma and alveolar rhabdomyosarcoma. In neuroblastoma, DDX1 amplification and overexpression are associated with poor patient prognosis. DDX1 is known to play a role in the repair of DNA double-strand breaks. Furthermore, inhibition of DDX1 expression sensitizes neuroblastoma cells to drugs that cause DNA damage. Therefore, we hypothesize that overexpression of DDX1 in MYCN-amplified neuroblastoma increases their resistance to DNA-damaging drugs. We will test this hypothesis by examining: (i) the effect of DNA damaging radiation and chemotherapy drugs on viability, cell cycle, and apoptosis, and (ii) efficiency of DNA double-strand break repair, in MYCN-amplified versus MYCN/DDX1-co-amplified neuroblastoma cell lines. To address the importance of DDX1 overexpression in the repair of DNA double-strand breaks, we will reduce DDX1 expression in MYCN/DDX1-co-amplified neuroblastoma cell lines and assess the survival of cells when treated with radiation and chemotherapy drugs. Finally, to determine DDX1's mechanism of action, we will study DDX1's interacting partners using DDX1 co-immunoprecipitation. DDX1's interacting protein partners will be identified by mass spectrometry. This research will lead to a better understanding of the role of DDX1 in treatment-resistant neuroblastoma and may identify additional targets that can be used to improve outcome in children with MYCN/DDX1-amplified neuroblastoma.