Funding outcome

Neuroblastoma (NB) is responsible for 15% of pediatric cancer deaths. While patient survival is high for low and intermediate-risk patients, over 60% of children diagnosed with high-risk NB do not survive past the age of 5. High-risk in NB is often associated with amplification (increased copies) of a cancer-causing gene called MYCN. DEAD box proteins are involved in all cellular functions related to RNA, and hence play a significant role in cell survival. Previous research undertaken by the Godbout lab indicates that the DEAD Box 1 (DDX1) gene is amplified along with the MYCN gene in about 50% of high-risk NB. The goal of this research project is to investigate the relationship between DDX1 expression levels and NB cell survival. Over the past year, we have compared the survival of NB cells treated with two chemotherapy drugs used in the clinic for the treatment of NB patients: doxorubicin and vincristine. We used NB cells that have MYCN amplification, and NB cells that have both MYCN and DDX1 amplification to examine the effect of DDX1 overexpression on NB cell survival. We also used an experimental approach called RNA-interference to investigate if knockdown of DDX1 (resulting in reduced levels of DDX1) played a role in NB cell survival. DDX1-knockdown in MYCN-amplified cell lines reduced NB cell survival in cells treated with doxorubicin, but no effect was observed with vincristine treatment. We will be continuing these experiments by examining the effects of DDX1-knockdown on NB cell survival in DDX1 and MYCN-amplified cell lines. I will examine additional chemotherapy drugs, such as etoposide and bleomycin. As part of my summer research, I will also examine the effects of DDX1 expression level on DNA double-stranded break repair via immunostaining with markers used to detect these breaks and their repair mechanism. Through this research, we will gain an understanding of how NB cells become resistant to treatment, which is critical for the development of more effective treatments for children with high-risk NB.