Abstract 1200: Aurora kinase A is a potential therapeutic target regulated by the MYCN oncogene in human retinoblastoma

Abstract

Abstract Retinoblastoma (RB) is a pediatric intraocular neoplasm characterized by loss of function mutations in the RB1 gene. RB has a near-perfect prognosis in developed countries, but a significant dip in patient survival is observed in low and middle-income nations, with an overall survival rate of around 40%. Chemotherapy is a primary treatment modality in RB. However, the immediate and long-term side effects of conventional and intra-arterial chemotherapies necessitate the need for additional treatment options. Aurora kinases are serine/threonine kinases that play a pivotal role in mitosis. In recent years, Aurora kinase A (AURKA) has gained prominence as a drug target in various tumors and several small molecule inhibitors of AURKA are currently in clinical development. In this study, we have shown that AURKA is overexpressed in RB patient specimens and cell lines using immunohistochemistry and immunoblotting. Moreover, induced expression of AURKA significantly correlated with optic nerve invasion of the tumor suggesting a role of AURKA in RB progression. Inhibition of AURKA in RB cell lines and patient specimens using small molecule inhibitors or selective silencing with lentivirus-mediated shRNA knockdown led to decreased cell viability, increased apoptosis, cell cycle arrest at G2/M phase and subsequent induction of polyploidy. To further investigate the deleterious effects of AURKA inhibition within the tumor microenvironment, chorio-allantoic membrane (CAM) xenografts with RB cells were performed. The in-ovo data revealed a delay in tumor growth when treated with AURKA inhibitors. MYCN is an essential oncogene in RB progression immediately to RB1 mutations. Notably, an in-silico promoter analysis predicted the presence of MYCN binding sites upstream of the transcription start site of AURKA. Chromatin immunoprecipitation - qPCR (ChIP-qPCR) confirmed the binding of MYCN to the promoter region of AURKA. Besides, immunoblots corroborated that AURKA was downregulated in MYCN knockdown RB cells. Overall, our findings show that elevated AURKA levels in RB could be targeted in-vitro and in-ovo, and its expression is transcriptionally regulated by the MYCN oncogene. These data not only shed light on the role of AURKA in RB tumorigenesis but also unravel its potential as a therapeutic target, in isolation or through MYCN-driven downstream pathways. Acknowledgements: Department of Biotechnology - Innovative Young Biotechnologist Award (DBT-IYBA to MMR), Ministry of Science and Technology, Government of India; Hyderabad Eye Research Foundation (HERF), L V Prasad Eye Institute, Bhubaneswar, India; Indian Council of Medical Research - Senior Research Fellowship (ICMR-SRF to NAB), Ministry of Health and Family Welfare, Government of India. Citation Format: Naheed Arfin Borah, Ruchi Mittal, Devjyoti Tripathy, Swathi Kaliki, Suryasnata Rath, Srinivas Patnaik, Mamatha M. Reddy. Aurora kinase A is a potential therapeutic target regulated by the MYCN oncogene in human retinoblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1200.