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Graphical Abstract 2 IDH3A CLU S100A7 PCBD-1 RAB1A RAB6A SerpinB3 M u t a n t 1 DEK/CAN RpS14 RpS19 M u t a n t 2 M u t a n t 3 M u ta n t 4 Subtractive proteomics DEK/CAN SFK MYC mTOR AKT ABL RPS14 RPS19 PCBD1 SerpB3 CLU RAB6A RAB1A S100A7 RAB5A RIN1 IDH3A STAT5 AKT mTOR SRC/SFK ABL c-MYC proliferation self renewal differentiation block apoptosis block therapy resistance DEK/CAN SummaryAcute myeloid leukemias (AML) are characterized by recurrent genomic alterations, often in transcriptional regulators, which form the basis on which current prognostication and therapeutic intervention is overlaid.In AML transformation can often be attributed to single chromosomal aberrations encoding oncogenes, such as t(15;17)-PML/RARα or t(6;9)-DEK/CAN but it is unclear how these aberrant transcription factors drive leukemic signaling and influence cellular responses to targeted therapies. Here we show that by using a novel "subtractive interaction proteomics" approach, the high risk AML-inducing oncogene t(6;9)-DEK/CAN directly activates signaling pathways that are driven by the ABL1, AKT/mTOR, and SRC family kinases. The interplay of these signaling pathways creates a network with nodes that are credible candidates for combinatorial therapeutic interventions. These results reveal specific interdependencies between nuclear oncogenes and cancer signaling pathways thus providing a foundation for the design of therapeutic strategies to better address the complexity of cancer signaling.

Patients within the WHO-subgroup of t(6;9)-positive acute myeloid leukemia (AML) differ from other AML subgroups as they are characterised by younger age and a grim prognosis. Leukemic transformation can often be attributed to single chromosomal aberrations encoding oncogenes, in the case of t(6;9)-AML to the fusion protein DEK-CAN (also called DEK-NUP214). As being a rare disease there is the urgent need for models of t(6;9)-AML. The only cell line derived from a t(6;9)-AML patient currently available is FKH1. By using phospho-proteomics on FKH1 cells, we found a strongly activated ABL1 kinase. Further investigation revealed the presence of ETV6-ABL1. This finding renders necessary to determine DEK-CAN- and ETV6-ABL1-related features when using FKH1. This can be done as ETV6-ABL1 activity in FKH1 is responsive to imatinib. Nevertheless, we provided evidence that both SFK and mTOR activation in FKH1 are DEK-CAN-related features as they were activated also in other t(6;9) and DEK-CAN-positive models. The activation of STAT5 previously shown to be strong in t(6;9)-AML and activated by DEK-CAN is regulated in FKH1 by both DEK-CAN and ETV6-ABL1. In conclusion, FKH1 cells still represent a model for t(6;9)-AML and could serve as model for ETV6-ABL1-positive AML if the presence of these leukemia-inducing oncogenes is adequately considered.Taken together, all our results provide clear evidence of novel and specific interdependencies between leukemia-inducing oncogenes and cancer signaling pathways which will influence the design of therapeutic strategies to better address the complexity of cancer signaling.

The WHO classifies t(6;9)-positive acute myeloid leukemia (AML) as a subgroup of high-risk AML because of its clinical and biological peculiarities, such as young age and therapy resistance. t(6;9) encodes the DEK/NUP214 fusion oncoprotein that targets only a small subpopulation of bone marrow progenitors for leukemic transformation. This distinguishes DEK/NUP214 from other fusion oncoproteins, such as PML/RARα, RUNX1/ETO, or MLL/AF9, which have a broad target population they block differentiation and increase stem cell capacity. A common theme among most leukemogenic fusion proteins is their aberrant localization compared to their wild-type counterparts. Although the actual consequences are widely unknown, it seems to contribute to leukemogenesis most likely by a sequester of interaction partners. Thus, we applied a global approach to studying the consequences of the aberrant localization of t(6;9)-DEK/NUP214 for its interactome. This study aimed to disclose the role of localization of DEK/NUP214 and the related sequester of proteins interacting with DEK/NUP214 for the determination of the biology of t(6;9)-AML. Here we show the complexity of the biological consequences of the expression of DEK/NUP214 by an in-depth bioinformatic analysis of the interactome of DEK/NUP214 and its biologically dead mutants. DEK/NUP214’s interactome points to an essential role for aberrant RNA-regulation and aberrant regulation of apoptosis and leukocyte activation as a significant determinant of the phenotype of t(6;9)-AML. Taken together, we provide evidence that the interactome contributes to the aberrant biology of an oncoprotein, providing opportunities for developing novel targeted therapy approaches.