MDM2 and DNMT1 inhibitors induce neuroblastoma cell death through p53-dependent and independent pathways

Neuroblastoma, a highly aggressive pediatric cancer, presents significant treatment challenges due to its rapid proliferation, and resistance to conventional therapies. Growing evidence emphasizes the critical role of epigenetic modifications in tumor progression.

In this study, we explored the therapeutic potential of the MDM2 inhibitor RG-7388 alongside the DNMT inhibitors CM-272 and SGI-1027 in SK-N-SH and IMR-32 neuroblastoma cells. We hypothesized that RG-7388, CM-272, and SGI-1027 would induce p21 upregulation, leading to cell cycle arrest and activation of cell death pathways.

Cells treated with the above listed drug exhibited significant cell death, as determined by cell viability and caspase-3/7 activation assays. qRT-PCR and Western blot analyses revealed increased expression of p21 and pro-apoptotic BAX, along with decreased levels of the anti-apoptotic protein BCL-XL. Notably, RG-7388 treatment induced substantial PARP cleavage, consistent with activation of apoptosis.These findings suggest that MDM2 and DNMT1 inhibition promotes apoptosis through a p21-driven mechanism. Importantly, DNMT1 inhibition could provide a therapeutic alternative for neuroblastomas with p53 mutations, where p53 dependent mechanism is ineffective.

Our results suggest that, if validated further, RG-7388, CM-272, and SGI-1027 could become effective therapeutic agents for treating aggressive neuroblastoma that may become resistant to first or second line of treatment.