부산대학교 도서관

In Acute Myeloid Leukemia (AML), distinguishing between chemoresistance driver mechanisms and cell plasticity in response to chemotherapy is challenging due to their interconnectedness. To address this issue, we generated an MLL-AF9-driven syngeneic mouse model of AML, which we evolved to develop resistance to a front-line chemotherapy regimen by repetitive exposure to a maximally-tolerated combination of cytarabine and doxorubicin. An RNA sequencing (RNAseq)-based profiling of the chemoresistant (Chemo R) AML subpopulation and its naive (Chemo N) counterpart revealed a significant upregulation in the expression of 326 genes in Chemo Rcells which were markedly enriched in gene sets related to splicing/mRNA processing. Notably, single-sample GSEA analysis of relapsed AML samples from the BEAT-AML cohort supported these findings, as they were enriched for the upregulation of genes in our chemoresistance gene signature. A combined in vivofunctional screening endeavor using a pool of 2098 shRNAs targeting these upregulated genes and a motif discovery analysis performed on the set of dysregulated transcripts in Chemo Rcells identified three candidate hits, Srrm1, Sf3b3, and Prpf8, which scored as chemotherapy-specific dependencies and were found to interact with central regulators of alternative splicing ( Figure 1A). Silencing these three candidate genes in our chemoresistant mouse model and the human AML cell lines, MOLM-14, MV4-11, and U937, evolved to become resistant to the combination of cytarabine and daunorubicin, revealed that the splicing regulator, SRRM1, is a critical vulnerability of chemoresistant leukemic cells.