nanaomycin-a and Neuroblastoma

Neuroblastoma is one of the most common childhood solid tumors. Because tumor suppressor genes are often hypermethylated in cancers, DNA methylation has emerged as a target for cancer therapeutics. Nanaomycin A, an inhibitor of DNA methyltransferase 3B, which mediates. To study the antitumor activity of nanaomycin A against neuroblastoma cell lines and its mechanism.. The anti-tumor effect of nanaomycin A on neuroblastoma cell lines was evaluated based on cell viability, DNA methylation levels, apoptosis-related protein expression, and neuronal-associated mRNA expression.. Nanaomycin A decreased genomic DNA methylation levels and induced apoptosis in human neuroblastoma cells. Nanaomycin A also upregulated the expression of mRNAs for several genes related to neuronal maturation.. Nanaomycin A is an effective therapeutic candidate for treating neuroblastoma. Our findings also suggest that the inhibition of DNA methylation is a promising anti-tumor therapy strategy for neuroblastoma.

Topics: Cell Line, Tumor; Child; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; DNA Methyltransferase 3B; Humans; Naphthoquinones; Neuroblastoma

After extensive research on radiochemotherapy, 5-year survival rates of children with high risk neuroblastoma still do not exceed 50%, owing to adverse side-effects exemplified by doxorubicin-induced cardiomyopathy. A promising new approach is the combination of conventional therapies with specific modulation of cell signaling pathways promoting therapeutic resistance, such as inhibition of aberrant kinase activity or re-expression of silenced tumor suppressor genes by means of chromatin remodeling. In this regard, we established a system that allows to identify potential drug targets as well as to validate respective candidate inhibitors in high-risk neuroblastoma model cell lines. Cell culture, drug exposure, shRNA-mediated knockdown and phenotype analysis are integrated into an efficient and versatile single well-based protocol. By utilizing this system, we assessed RG108, SGI-1027 and nanaomycin A, three novel DNA methyltransferase inhibitors that have not been tested in neuroblastoma cell lines so far, for their potential of synergistic anti-tumor activity in combination with doxorubicin. We found that, similarly to azacytidine, SGI-1027 and nanaomycin A mediate synergistic growth inhibition with doxorubicin independently of N-Myc status. However, they display high cytotoxicity but lack global DNA demethylation activity. Secondly, we conducted a lentiviral shRNA screen of F-box proteins, key regulators of protein stability, and identified Fbxw11/β-TrCP2 as well as Fbxo5/Emi1 as potential therapeutic targets in neuroblastoma. These results complement existing studies and underline the reliability and versatility of our single well-based protocol.

Topics: Aminoquinolines; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cell Proliferation; DNA Methylation; DNA Modification Methylases; Doxorubicin; Drug Synergism; Enzyme Inhibitors; F-Box Proteins; HEK293 Cells; Humans; Molecular Targeted Therapy; Naphthoquinones; Neuroblastoma; Phthalimides; Pyrimidines; RNA, Small Interfering; Tryptophan