Abstract 5851: Dysregulated RNA splicing promotes AML quiescence and chemoresistance

Abstract

Abstract Chemotherapy is the first-line treatment for patients with acute myeloid leukemia (AML). Although most achieve initial remission, an estimated 50% of patients will relapse with poor clinical outcome. The paucity of genetic lesions in AML patients that relapse from chemotherapy implicate non-genetic alterations that mediate chemoresistance. In this study, we conducted a longitudinal analysis of alternative splicing changes in a cohort of 19 AML patients at diagnosis and relapse post-chemotherapy treatment. We found that the long isoform of the transcription factor-encoding gene RUNX1 (also known as RUNX1C) is upregulated in AML relapse cohorts and conferred chemotherapy resistance. Mechanistically, we show that B cell translocation gene 2 (BTG2) is an RUNX1C isoform-specific transcriptional target that promote transition into a quiescent and treatment-resistant state. Direct targeting of RUNX1C mRNA augments chemotherapy response in AML patient-derived xenograft (PDX) models in vivo. These findings uncover an isoform-specific functionality that influences chemotherapy responsiveness and offers a therapeutic strategy to sensitize leukemic cells to conventional chemotherapy treatments. Citation Format: Eric Wang, Cuijuan Han, Alexander Calderon, Abimbo Lawal, Nidhi Hariramani, Edie Crosse, Robert Bradley. Dysregulated RNA splicing promotes AML quiescence and chemoresistance [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 5851.