Epigenetic modulation by DNMT-1 inhibitor induces cell death in SK-N-AS neuroblastoma cells

Neuroblastoma (NB) is one of the most common extra-cranial solid tumors that is typically found in newborns and infants. Unfortunately, most children are present with advanced diseases and have poor prognosis at the time of diagnosis. Although the treatment of neuroblastoma has significantly improved with recent therapeutic strategies, many patients still do not benefit from them. As a result, new treatment approaches that can control aggressive and resistant tumors are urgently needed. Epigenetic regulation through DNA methylation and histone modifications have been shown to play a critical role in neuroblastoma progression, similar to the phenomenon seen in many other types of cancers. In this regard, DNMT's are commonly upregulated in aggressive neuroblastoma cells, contributing to transcriptional repression of tumor suppressor pathways. Therefore, in this study, we investigated the effect of the DNMT/G9a inhibitor CM-272 on cell survival in SK-N-AS neuroblastoma cells. Treatment of neuroblastoma cells with CM-272 at a concentration of 2 µM resulted in significant cell death, due to activation of the programmed cell death (PCD) cascade caused by elevated levels of apoptotic markers. In addition, CM-272 markedly suppressed DNMT-1 expression, confirming its ability to disrupt DNA methylation dependent gene silencing. In multiple cancer types, apoptosis induction was validated by enhanced cleavage of PARP accompanied by elevation of BAX and Caspases. Furthermore, CM-272 treatment elevated BAX expression, with downregulated BCL-2 levels, Intrinsic Pathway activation. In addition to the above analyses, miRNA expression profiling was performed using the NanoString Human miRNA panel. To fully explore post-transcriptional regulatory mechanisms that may be associated with CM-272 treatment. Together, these results demonstrate that CM-272 can induces apoptosis in SK-N-AS neuroblastoma cells by targeting epigenetic regulators and activating cell death pathways. Our findings suggest that CM-272 has strong therapeutic potential, as an epigenetic modifier drug, particularly in neuroblastoma tumors that are resistant to conventional treatments. Acknowledgements: This project was supported by the National Pediatric Cancer Foundation (NPCF). This research was also partially funded by the Bankhead Coley Infrastructure Development Grant from the Florida Department of Health that was awarded to A.R. through the Department of Pharmacology of the University of Miami (Coral Gables, Florida USA). The authors would like to thank Royal Dames of Cancer Research Inc. (Ft. Lauderdale, Florida) for their financial support in conducting this research