Integrated genomic analyses identify WEE1 as a critical mediator of cell fate and a novel therapeutic target in acute myeloid leukemia

Abstract

Acute myeloid leukemia (AML) remains a therapeutic challenge despite increasing knowledge about the molecular origins of the disease, as the mechanisms of AML cell escape from chemotherapy remain poorly defined. We hypothesized that AML cells are addicted to molecular pathways in the context of chemotherapy and used complementary approaches to identify these addictions. Using novel molecular and computational approaches, we performed genome-wide shRNA screens to identify proteins that mediate AML cell fate after cytarabine exposure, gene expression profiling of AML cells exposed to cytarabine to identify genes with induced expression in this context, and examination of existing gene expression data from primary patient samples. The integration of these independent analyses strongly implicates cell cycle checkpoint proteins, particularly WEE1, as critical mediators of AML cell survival after cytarabine exposure. Knockdown of WEE1 in a secondary screen confirmed its role in AML cell survival. Pharmacologic inhibition of WEE1 in AML cell lines and primary cells is synergistic with cytarabine. Further experiments demonstrate that inhibition of WEE1 prevents S-phase arrest induced by cytarabine, broadening the functions of WEE1 that may be exploited therapeutically. These data highlight the power of integrating functional and descriptive genomics, and identify WEE1 as potential therapeutic target in AML.

MAPK signaling cascades mediate distinct glucocorticoid resistance mechanisms in pediatric leukemia

“…17 These analyses revealed 206 genes involved in modulating the cellular response to prednisolone in ALL, including 102 identified by both analyses (P , 1 3 10 230 ; Figure 1B Figure 2). Notably, genes associated with kinase signaling were the most enriched category, many of which are associated with MAPK signaling cascades ( Figure 1D and supplemental Figure 2).…”

“…Viral preparation, genome-wide shRNA screening, 17 real-time quantitative polymerase chain reaction, 18 apoptosis assays, 18 cell viability assays, 18 immunoblots, 18 phospho flow cytometry, 19 and xenograft models [20][21][22][23] were all performed as previously described with additional details and modifications available in the supplemental Methods, found on the Blood Web site.…”

Synergistic anti-leukemic interactions between panobinostat and MK-1775 in acute myeloid leukemia ex vivo

“…36,40,51,52 The combined cytarabine and MK-1775 treatments resulted in synergistic inhibition of proliferation, regardless of p53 status. 40 It has been demonstrated that cytarabine-induced S-phase cell cycle arrest was overcome by the addition of MK-1775.…”

“…40 It has been demonstrated that cytarabine-induced S-phase cell cycle arrest was overcome by the addition of MK-1775. 40, 51,52 Tibes et al used an RNAi screening approach to identify kinases involved in cytarabine sensitivity and found ATR, PKMYT1, and CHK1, among others, as kinases involved in cytarabine sensitivity. 36 In addition, they demonstrated synergistic anti-leukemic activity for combined MK-1775 and cytarabine treatment in cell line models.…”

HSC commitment–associated epigenetic signature is prognostic in acute myeloid leukemia

“…The signature mainly consisted of loci that were significantly demethylated during commitment from STHSC to CMP (516/561 loci, 92.0%). Interestingly, this stem cell commitment-associated epigenetic signature was enriched in loci associated with several genes that are commonly implicated not only in human HSC function and commitment but also in leukemogenesis, such as CEBPA (27)(28)(29), E2F1 (30), KRAS (31,32), and WEE1 (33) as well as a noncoding transcript, MIRLET7B (ref. 34 and Supplemental Table 4).…”