Here we describe a miRNA, miR-380-5p, that represses p53 expression via a conserved sequence in the p53 3' untranslated region (UTR). miR-380-5p is highly expressed in mouse embryonic stem cells and neuroblastomas, and high expression correlates with poor outcome in neuroblastomas with neuroblastoma derived v-myc myelocytomatosis viral-related oncogene (MYCN) amplification. miR-380 overexpression cooperates with activated HRAS oncoprotein to transform primary cells, block oncogene-induced senescence and form tumors in mice.
Additionally, Ras family members (Hras1, Kras2 and Nras) and the downstream effectors Pik3ca and Braf, were sequenced from twenty-five neuroblastomas arising in neuroblastoma-prone transgenic mice.
Favorable outcomes of patients with advanced NB were distinguished by high Ha-ras and high trk A expression, and unfavorable outcomes were distinguished by low Ha-ras and low trk A expression.
To evaluate the correlation between telomerase activity and other biological characteristics reported as prognostic markers (MYCN gene amplification, loss of heterogeneity (LOH) in the short arm of chromosome 1, trk-A expression, Ha-ras p21 expression, and DNA ploidy), we investigated these biological features in 105 untreated neuroblastomas.
These findings from unmanipulated human neuroblastomas indicate that the Ha-ras gene product (p21) might play a role in the mechanism(s) controlling aggressiveness in this type of tumor in vivo and that the Ha-ras p21 detected by a simple and reproducible immunohistochemical procedure may be of clinical importance in predicting prognosis in patients with this malignancy.