Z. Aburjania1, A. Janssen1, S. Jang1, H. Chen1, R. Jaskula-Sztul1 1The University Of Alabama At Birmingham,Surgery,Birmingham, Alabama, USA
Introduction:
Neuroblastoma is a highly aggressive tumor of childhood with 5year survival rate of 68% for children aged 1 to 14 years. It is derived from sympathoadrenal lineage of the neural crest progenitor cells. Notch signaling has important role in determining cell fate during differentiation of ectodermal cells in the sympathetic nervous system. Notch pathway is associated with low differentiation of neuroblastoma, activation of proliferation and motility of cancer cells. Histone deacetylase inhibitors (HDACi) are well-known for their anti-tumor activity as well as their ability to regulate Notch signaling. We tested a novel HDACi Thailandepsin-A (TDP-A) as a treatment option for neuroblastoma.
Methods:
Methylthiazolyldiphenyl-tetrazolium bromide (MTT) rapid colorimetric assay was used to determine the IC50 of TDP-A on LA-N-5, NGP and SK-N-SH neuroblastoma cell lines. The effect of TDP-A on Notch1 and apoptotic markers p21 and p27 were assessed by western blot after treatment of neuroblastoma cells with DMSO, 3nM and 6nM TDP-A. Additionally N-myc-amplified NGP cell lysates were assessed for N-myc protein levels. Cells were also assessed for neurite outgrowth as a sign of differentiation.
Results:
IC50 was determined to be 4nM, 4nM and 6nM for LA-N-5, NGP and SK-N-SH cell lines respectively. Western blot analysis showed decrease of Notch1 in all cell lines. p27 levels increased with the treatment in LA-N-5 cells. NGP cell line showed increase of p21 protein. N-myc levels decreased in NGP cell lines with the treatment of TDP-A. Increase of neurite outgrowth was observed with the treatment in LA-N-5 cells (12.5um vs 47.8um, p=0.464).
Conclusion:
TDPA has potent anti-proliferating effect on neuroblastoma cell lines in low nanomolar concentrations. It decreased Notch1 in all cell lines together with decrease of N-myc in NGP that is known to have amplified N-myc gene, which is observed in one-third of neuroblastomas and correlated with advanced disease. These results show that TDPA is a promising drug for treatment of neuroblastoma.