Distinct and Cooperative Effects of Epigenetic Inhibitors on Cell Viability and Cell Cycle Regulation in Neuroblastoma Cells

Distinct and Cooperative Effects of Epigenetic Inhibitors on Cell Viability and Cell Cycle Regulation in Neuroblastoma Cells

Alvin Sherman Library

Epigenetic dysregulation plays a central role in uncontrolled cell proliferation and therapeutic resistance in cancer. Consequently, targeting epigenetic regulators with small-molecule inhibitors has emerged as a promising strategy to disrupt cell cycle progression and induce tumor cell death. In this study, we evaluated the cytotoxic and molecular effects of two epigenetic-targeting agents, CM-272 and JNJ-64619178, administered as individual, simultaneous, and sequential treatments in neuroblastoma cell models. Cell viability was assessed using XTT assays, and changes in cell cycle regulatory proteins were analyze by Western blotting. Our results demonstrate that simultaneous combination treatment produced the greatest reduction in cell viability compared with individual or sequential regimens. Molecular analysis revealed a consistent upregulation of the cyclin-dependent kinase inhibitor p21 along with a reduction in p53 protein levels in combination-treated cells. Notably, individual treatment with CM-272 induced p21 expression without corresponding p53 activation, suggesting a p53-independent mechanism of p21 regulation. In contrast, JNJ-64619178 treatment resulted in decreased p53 levels without detectable p21 induction, indicating that these agents may modulate cell cycle arrest and cell death through distinct molecular mechanisms. Together, these findings suggest that the enhanced cytotoxicity observed with simultaneous treatment arises from complementary epigenetic effects rather than redundant pathways. Ongoing studies aim to further characterize treatment-associated epigenetic alterations by examining chromatin- and DNA methylation-related biomarkers using quantitative real-time PCR> Overall, this work highlights the importance of combinatorial epigenetic targeting strategies in impairing neuroblastoma cell viability.