Abstract 2865: Efficacy of MDM2 and epigenetic inhibitors treatments for neuroblastoma
Authors: Momenah Tahani , Natarajan Umamaheswari , Jaganathan Shyam , Rathinavelu Appu 
Published: March 2024

Pediatric Neuroblastoma (NB) is one of the most prevalent solid tumors in children that arise from embryonic neural crest cells and poses a significant challenge in the field of oncology. There are about 700 to 800 new cases of neuroblastoma diagnosed each year in the United States, and accounts for approximately 15% of all childhood cancer mortalities. Since this malignancy predominantly affects infants and young children, it is imperative to decipher the underlying molecular factors driving its pathogenesis. The novel molecular therapeutic approach includes the use of epigenetic modifiers as drugs. This approach aims to reverse significant epigenetic events underlying cancer pathogenesis, particularly abnormalities in histone modifications and DNA methylation. The reduction of both DNA and histone methylation levels leads to the reactivation of tumor suppressor genes and inhibits cancer cell proliferation and cell growth. In this study, we used selective and reversible small molecule agents such as MDM2 inhibitor (RG7388) and epigenetic modifiers (CM272 and SAHA) to block cell proliferation by inducing cell cycle arrest via enforcing Epigenetic alterations. Our initial experiments were designed to understand the effects of RG7388, CM272, and SAHA treatments on NB and their impact on cell cycle progression. It was hypothesized that the decrease in DNA methylation and increase in histone modification- augment p21 expression via the use of MDM2 inhibitors and epigenetic modifiers. To test this hypothesis, the NB cells (SK-N-SK and IMR-32) were treated with RG7388, CM272, and SAHA for 24 hours. The extent of Cell death was determined for NB cells by using the Trypan Blue Dye Exclusion (TBDE) method, and CellTiter-Glo® Luminescent Cell Viability Assay. Induction of apoptosis was determined by using the Immunofluorescence staining method with DEVD-amc substrate. The results of our study suggested that RG7388, CM272, and SAHA were able to induce cell death in the SK-N-SH cells following 24-hour treatment.

Furthermore, we analyzed the levels of Tumor suppressor (p53), cell cycle arrest (p21, p27, AurkB, CDC25A, CyclinD) cell death (Bax, Bcl2, LC3, Beclin, PARP, Cleaved PARP, RIP1, RIP3, MLKL, p-AKT), and Epigenetic biomarker (DNMT1, DNMT3A, DNMT3B, acetyl histoneH3, H4, and H2b) protein expression levels using western blot analysis. The results showed significant elevation of p53, p21, p27, and acetylation of histone family biomarkers after treatment when compared with the control group. In summary, our results indicate that RG7388, CM272, and SAHA treatments can effectively induce cellular responses and prevent cell growth and progression by enforcing epigenetic changes in the NB cells. (This research was supported by the National Pediatric Cancer Foundation, Tampa, Florida, and the Royal Dames of Cancer Research Inc. of Ft. Lauderdale, Florida)

Citation Format: Tahani Momenah, Umamaheswari Natarajan, Shyam Jaganathan, Appu Rathinavelu. Efficacy of MDM2 and epigenetic inhibitors treatments for neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2865.