Abstract 5363: MicroArray-based MethylationToActivity: Advancing biological knowledges from DNA methylation profiles of patient tumors

Abstract DNA methylation (DNAm) is a relatively stable regulatory epigenetic mechanism. Although accurate DNAm classifiers have been built for early detection of cancer and subtype classifications, its transcriptional regulatory roles remain unclear. To address this challenge, we developed a deep-learning framework MethylationToActivity (M2A) that accurately predicts individual promoter activity from WGBS methylomes. As array-based methylome is the most common epigenetic data from patients’ tumor samples, we redesigned M2A’s raw features and model topology for array methylomes, which shows an accurate prediction of the promoter activity (R2 = 0.74), approaching its WGBS counterpart (R2 = 0.79). Transfer learning improves the prediction accuracy to 0.77. In a primary rhabdomyosarcoma cohort, M2A prioritized candidate genes with strong subtype-specific alternative promoter usage (APU) and identified distinct isoforms of a subgroup of APU genes including NAV2 expressed in the two major subtypes (aRMS and eRMS). Molecular experiments revealed that PAX3-FOXO1 directly binds to the aRMS-specific promoter and is required for its active transcription. Genetic deletion of PAX3-FOXO1 leads to NAV2 APU. Overexpression of aRMS-specific NAV2 isoform significantly promoted cell proliferation, supporting its oncogenic function. These data indicate that PAX3-FOX1 is critical for APU in aRMS. We conclude that the new M2A provides vast insight into downstream functional interpretation of differential DNAm patterns. Citation Format: Karissa Dieseldorff Jones, Waise Quarni, Daniel Putnam, Shivendra Singh, Qiong Wu, Jun Yang, Xiang Chen. MicroArray-based MethylationToActivity: Advancing biological knowledges from DNA methylation profiles of patient tumors. [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 5363.