T-cell acute lymphoblastic leukemia (T-ALL) is a high-risk subtype of acute lymphoblastic leukemia (ALL) with gradually improved survival through introduction of intensified chemotherapy. However, therapy-resistant or refractory T-ALL remains a major clinical challenge. Here, we evaluated B-cell lymphoma (BCL)-2 inhibition by the BH3 mimetic ABT-199 as a new therapeutic strategy in humanT-ALL. The T-ALL cell line LOUCY, which shows a transcriptional program related to immature T-ALL, exhibited high in vitro and in vivo sensitivity for ABT-199 in correspondence with high levels of BCL-2. In addition, ABT-199 showed synergistic therapeutic effects with different chemotherapeutic agents including doxorubicin, L-asparaginase, and dexamethasone. Furthermore, in vitro analysis of primary patient samples indicated that some immature, TLX3- or HOXA-positive primary T-ALLs are highly sensitive to BCL-2 inhibition, whereas TAL1 driven tumors mostly showed poor ABT-199 responses. Because BCL-2 shows high expression in early T-cell precursors and gradually decreases during normal T-cell differentiation, differences in ABT-199 sensitivity could partially be mediated by distinct stages of differentiation arrest between different molecular genetic subtypes of human T-ALL. In conclusion, our study highlights BCL-2 as an attractive molecular target in specific subtypes of human T-ALL that could be exploited by ABT-199.

dx.doi.org/10.1182/blood-2014-05-574566, hdl.handle.net/1765/85904
Department of Pediatrics

Peirs, S, Matthijssens, F, Goossens, S, Van De Walle, I, Ruggero, K, De Bock, C.E, … van Vlierberghe, P. (2014). ABT-199 mediated inhibition of BCL-2 as a novel therapeutic strategy in T-cell acute lymphoblastic leukemia. Blood, 124(25), 3738–3747. doi:10.1182/blood-2014-05-574566