Abstract 4421: Chemotherapy-induced DNA damage triggers caspase-dependent degradation of N6-methyladenosine reader YTHDF proteins, reshaping the cancer transcriptome

Abstract N6-methyladenosine (m6A) modification plays a crucial role in DNA damage response (DDR), which is the primary mechanism targeted by most chemotherapeutic agents. Here, we investigated the dynamic regulation of m6A-related molecules during chemotherapy-induced DNA damage. Anthracycline treatment led to a significant reduction in protein levels, but not mRNA levels, of m6A readers YTHDF1, YTHDF2, and YTHDF3. It was consistently observed with other chemotherapeutic agents, including 5-fluorouracil (5-FU) and oxaliplatin. Notably, this reduction occurred independently of p53 status, as YTHDF proteins remained unchanged upon p53 overexpression alone, while their reduction was still observed in p53-knockout cells treated with doxorubicin. Mechanistic studies showed that the decrease in YTHDF proteins was primarily associated with topoisomerase II inhibition rather than reactive oxygen species (ROS) generation, which are both known mechanisms of doxorubicin. Further investigation revealed decreased protein stability of YTHDFs upon doxorubicin treatment, which was primarily attributed to activated caspase-mediated degradation during apoptosis rather than proteasomal degradation or autophagy. RNA sequencing analysis of YTHDF2-overexpressing cells showed differential enrichment of MYC targets V1, V2 pathway upon doxorubicin treatment, indicating a potential role for YTHDF2 in modulating oncogenic pathways during chemotherapy response. Collectively, our findings unveil mechanisms of m6A reader regulation during chemotherapy and suggest potential therapeutic implications for cancer treatment through manipulation of m6A-mediated gene regulation. Citation Format: Sang Eun Lee, Sung-Yup Cho. Chemotherapy-induced DNA damage triggers caspase-dependent degradation of N6-methyladenosine reader YTHDF proteins, reshaping the cancer transcriptome [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 4421.