Abstract 4238: DNMT1 inhibition by SGI-1027 promotes neuroblastoma cell death through a p53-independent pathway

Abstract Introduction: Neuroblastoma is an aggressive childhood cancer originating from neural crest cells, accounting for 700-800 new cases annually and cuases15% of pediatric cancer deaths in the U.S. Treatment for high-risk neuroblastoma includes chemotherapy, stem cell transplants, radiation, and immunotherapy. Recent evidence suggests that DNMTs inhibitors such as SGI-1027 and CM-272 can potentiate apoptosis via epigenetic modulation of critical regulatory pathways in cancers. Hence, we hypothesized that SGI-1027 can induce apoptosis in SK-N-SH neuroblastoma cells by upregulating p21 through DNMT1 inhibition. Our study aimed to elucidate the underlying mechanisms and assess the potential of using SGI-1027 for treating high-risk neuroblastoma. Methods: SK-N-SH cells were treated with 2 µM of SGI -1027 for 24 hrs. The cell viability was evaluated using Trypan Blue Dye Exclusion method, while apoptotic activity was quantified through a fluorescence assay using DEVD-amc substrate for measuring caspase-3/7 activation. qRT-PCR and Western Blot analyses were conducted to assess expression levels of the cell cycle, apoptotic, and epigenetic pathway-related markers such as p53, p21, PARP, BAX, BCL-XL, and DNMT1. Apoptotic changes in cells were further confirmed through Immunofluorescence studies. Results: Our study results confirmed that SK-N-SH cells treated with SGI-1027 showed significant cell death and enhanced fluorescence in the DEVD-amc, indicating activation of apoptotic activity. Consistent with our hypothesis, we observed an elevation in p21 levels, an increased BAX/BCL-XL ratio, and a downregulation in the levels of DNMT1, suggesting that SGI-1027 may be facilitating neuroblastoma cell death through a p21-driven mechanism that is independent of p53 pathway. Conclusion: This study highlights the potential of DNMT1 inhibitor SGI-1027 to induce apoptosis in neuroblastoma cells through upregulating p21 and modulating the BAX/BCL-XL ratio. Our findings suggest that targeting DNMT1 using SGI-1027 may offer an effective pathway for inducing cell death and controlling neuroblastoma growth. We are in the process of validating DNMT1 targeted therapies as a powerful addition for treating aggressive neuroblastoma. Acknowledgments: This project was supported by the National Pediatric Cancer Foundation (NPCF) and the Royal Dames of Cancer Research Inc., Fort Lauderdale, Florida. Citation Format: Farah Naz, Shyam Sundar Jaganathan, Umamaheswari Natarajan, Appu Rathinavelu. DNMT1 inhibition by SGI-1027 promotes neuroblastoma cell death through a p53-independent pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4238.