Journal
BMC CANCER
Volume 11, Issue -, Pages -Publisher
BMC
DOI: 10.1186/1471-2407-11-33
Keywords
-
Categories
Funding
- Science Foundation Ireland [07/IN.1/B1776]
- Children's Medical and Research Foundation
- NIH [5R01CA127496]
- Assisi Foundation of Memphis
- US Public Health Service [CA23099]
- Cancer Center, National Cancer Institute [21766]
- American Lebanese Syrian Associated Charities (ALSAC)
Ask authors/readers for more resources
Background: Neuroblastoma is a paediatric cancer which originates from precursor cells of the sympathetic nervous system and accounts for 15% of childhood cancer mortalities. With regards to the role of miRNAs in neuroblastoma, miR-34a, mapping to a chromosome 1p36 region that is commonly deleted, has been found to act as a tumor suppressor through targeting of numerous genes associated with cell proliferation and apoptosis. Methods: A synthetic miR-34a (or negative control) precursor molecule was transfected into NB1691(luc) and SK-N-AS(luc) neuroblastoma cells. Quantitative PCR was used to verify increased miR-34a levels in NB1691(luc) and SK-N-AS(luc) cell lines prior to in vitro and in vivo analysis. In vitro analysis of the effects of miR-34a over expression on cell growth, cell cycle and phosphoprotein activation in signal transduction pathways was performed. Neuroblastoma cells over expressing miR-34a were injected retroperitoneally into immunocompromised CB17-SCID mice and tumor burden was assessed over a 21 day period by measuring bioluminescence (photons/sec/cm(2)). Results: Over expression of miR-34a in both NB1691(luc) and SK-N-AS(luc) neuroblastoma cell lines led to a significant decrease in cell number relative to premiR-negative control treated cells over a 72 hour period. Flow cytometry results indicated that miR-34a induced cell cycle arrest and subsequent apoptosis activation. Phosphoprotein analysis highlighted key elements involved in signal transduction, whose activation was dysregulated as a result of miR-34a introduction into cells. As a potential mechanism of miR-34a action on phosphoprotein levels, we demonstrate that miR-34a over-expression results in a significant reduction of MAP3K9 mRNA and protein levels. Although MAP3K9 is a predicted target of miR-34a, direct targeting could not be validated with luciferase reporter assays. Despite this fact, any functional effects of reduced MAP3K9 expression as a result of miR-34a would be expected to be similar regardless of the mechanism involved. Most notably, in vivo studies showed that tumor growth was significantly repressed after exogenous miR-34a administration in retroperitoneal neuroblastoma tumors. Conclusion: We demonstrate for the first time that miR-34a significantly reduces tumor growth in an in vivo orthotopic murine model of neuroblastoma and identified novel effects that miR-34a has on phospho-activation of key proteins involved with apoptosis.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available