Abstract
Chemoresistance remains a major challenge in addressing T-cell lymphoblastic lymphoma/leukemia (T-LBL/ALL), underscoring the necessity for novel strategies to unravel the molecular factors driving resistance. Through transcriptomic profiling, circBPTF was found to be markedly overexpressed in chemoresistant samples. Further functional experiments demonstrated that BPTF-665aa, the protein product of circBPTF, plays a pivotal role in mediating resistance. Notably, BPTF-665aa prevents the ubiquitination degradation of full-length BPTF, and promotes chromatin accessibility at key promoter sites, such as that of c-Myc promter 2 (P2), facilitating transcriptional activation crucial for cellular survival and proliferation under therapeutic stress. Structural studies confirmed the motifs of BPTF-665aa, including the Plant Homeodomain (PHD) finger and Bromodomain, essential for its chromatin remodeling function. HY-B0509 was identified as a small-molecule inhibitor of BPTF-665aa, with molecular docking and dynamics simulations showing stable binding to critical residues within the protein's active site. Overall, this study introduces a new mechanism where circBPTF affects chromatin accessibility, causing chemoresistance, making BPTF-665aa as a potential therapeutic target for treating T-LBL/ALLs.