Poster Presentation Advances in Neuroblastoma Research Congress 2016

MicroRNA-204 suppresses neuroblastoma tumour growth through down-regulation of MYCN oncogene (#196)

Chi Yan Ooi 1 , Daniel R Carter 1 , Bing Liu 1 , Anneleen Beckers 2 , Sara De Brouwer 2 , Katleen De Preter 2 , Murray D Norris 1 , Michelle Haber 1 , Frank Speleman 2 , Tao Liu 1 , Belamy B Cheung 1 , Glenn M Marshall 1 3
  1. Children’s Cancer Institute Australia for Medical Research, University of New South Wales, Sydney, Australia
  2. Center for Medical Genetics (CMGG), Ghent University, Ghent, Belgium
  3. Kids Cancer Centre, Sydney Children’s Hospital, Sydney, Australia

MYCN acts as a major oncogenic driver through pleiotropic effects controlled by multiple protein encoding genes as well as microRNAs (miRNAs) in neuroblastoma. MYCN activity is tightly regulated at the level of transcription and protein stability through various mechanisms. MYCN is further controlled by miRNAs, but the full complement of all miRNAs implicated in this process has not been determined through an unbiased approach. To elucidate the role of miRNAs in regulation of MYCN in neuroblastoma, we investigated the global miRNAs and mRNAs expression pattern in the TH–MYCN neuroblastoma mouse model and age-matched wild-type mice during the pre-tumour stage. Five miRNAs were selected to be examined further for their correlation to human patient prognosis and MYCN amplification. One of these miRNAs, miRNA-204 showed reduced expression in ganglia tissues of TH–MYCN versus wild-type mice. High miR-204 expression is significantly associated with better overall and event-free survivals, and also associated with low clinical stage. Moreover, high miRNA-204 expression correlated with non-MYCN-amplified human neuroblastoma tumour tissues. miRNA-204 expression is increased with MYCN siRNAs knockdown in MYCN-amplified BE(2)-C and Kelly neuroblastoma cells. Furthermore, chromatin immunoprecipitation assays revealed MYCN directly bound to the DNA region which encodes the miRNA-204 primary transcript in BE(2)-C cells. Importantly, transient transfection of miRNA-204 mimic or stably overexpression of miRNA-204 using doxycycline-inducible lentiviral construct significantly reduced MYCN mRNA and protein expressions, reduced cell proliferation and colony forming capacity both BE(2)-C and Kelly cell lines. Preliminary data from doxycycline-induced miRNA-204 overexpression in subcutaneous xenografts of stable BE(2)-C and Kelly cell lines showed reduced tumour growth in the animal models. For the first time, our data suggest that MYCN transcriptionally suppressed miRNA-204 by direct binding to its promoter, and miR-204 suppressed neuroblastoma cell growth through down-regulation of MYCN.