Deborah Bongiovanni, Gloria Milani, Annalisa Martines, Alberto Amadori, Pieter Van Vlierberghe, Wouder Van Loocke, Sonia Minuzzo, Filip Matthijssens, Barbara Buldini, Valeria Tosello, Erich Piovan, Nadia Macri, Richard Fabian Schumacher, Tosello, Valeria, Milani, Gloria, Martines, Annalisa, Macri, Nadia, Van Loocke, Wouder, Matthijssens, Filip, Buldini, Barbara, Minuzzo, Sonia, Bongiovanni, Deborah, Schumacher, Richard Fabian, Amadori, Alberto, Van Vlierberghe, Pieter, and Piovan, Erich
MYC-translocated T-lineage acute lymphoblastic leukemia (T-ALL) is a rare subgroup of T-ALL associated with CDKN2A/B deletions, PTEN inactivation, and absence of NOTCH1 or FBXW7 mutations. This subtype of T-ALL has been associated with induction failure and aggressive disease. Identification of drug targets and mechanistic insights for this disease are still limited. Here, we established a human NOTCH1-independent MYC-translocated T-ALL cell line that maintains the genetic and phenotypic characteristics of the parental leukemic clone at diagnosis. The University of Padua T-cell acute lymphoblastic leukemia 13 (UP-ALL13) cell line has all the main features of the above described MYC-translocated T-ALL. Interestingly, UP-ALL13 was found to harbor a heterozygous R882H DNMT3A mutation typically found in myeloid leukemia. Chromatin immunoprecipitation coupled with high-throughput sequencing for histone H3 lysine 27 (H3K27) acetylation revealed numerous putative super-enhancers near key transcription factors, including MYC, MYB, and LEF1. Marked cytotoxicity was found following bromodomain-containing protein 4 (BRD4) inhibition with AZD5153, suggesting a strict dependency of this particular subtype of T-ALL on the activity of super-enhancers. Altogether, this cell line may be a useful model system for dissecting the signaling pathways implicated in NOTCH1-independent T-ALL and for the screening of targeted anti-leukemia agents specific for this T-ALL subgroup.