2009;114:3008C3017. typifies acute monocytic leukemia when compared with all other AML sub-types. We validated expression of this signature in cell lines and main cells from AML patients. Interestingly, this signature is usually enriched for genes that control cell motility at different levels. As a consequence, inhibiting HIF-1 impaired leukemia cell migration, chemotaxis, invasion and transendothelial migration gene on chromosome 11q23, and mutations in and [10C13, 9], with mutations associated with favorable prognosis, and and mutations and rearrangements associated with adverse prognosis [14]. Hypoxia inducible transcription factors (HIFs) are the main regulators of adaptive responses to low oxygen concentrations and are often up-regulated in solid tumors as a result of intra-tumoral hypoxia or activation of specific oncogenic pathways [15]. HIFs regulate a vast array of cellular responses in tumors, including metabolism, cell migration, invasion, metastasis and angiogenesis, and their expression often correlates with poor clinical end result and patients survival [15C19]. In leukemia, the study of HIF factors has lagged behind for a number of years, and only recently their expression and function are beginning to be characterized. In AML in particular, a number of studies with human cells and xenograft mouse models have recently suggested that HIF-1 and HIF-2 play pro-leukemogenic functions by regulating leukemia Rabbit Polyclonal to ZNF134 progression and maintenance of leukemia initiating cells (LICs). As a consequence, their inhibition prospects to leukemia de-bulking and eradication [20C25]. In apparent contrast with these results however, recent evidence obtained in mouse models of AML suggests that genetic deletion of or may rather promote development and/or maintenance of LICs in the presence of specific leukemogenic mutations, such as KRas G12C inhibitor 4 MLL rearrangements or AML1-ETO, while having no apparent effect on the progression of established leukemia [26C27]. Therefore, further characterization of the role of these factors in different AML sub-types is needed to reconcile these contrasting results and conclusively elucidate the potential of HIF inhibition for leukemia treatment. Here, to better elucidate the involvement of hypoxia signaling in unique AML sub-types, we applied a previously explained list of HIF-1 target genes [24, 28] to the transcriptomic profiles of AML patients sub-categorized according to the FAB classification. We found that besides AML-M3, which we had previously identified as an AML sub-type with specific up-regulation of hypoxia signaling [24, 28], AML-M5 patients display specific up-regulation of a number of HIF-1-target genes implicated in cell migration, invasion and transendothelial migration. In accordance with these data, inhibition of HIF-1 in a number of AML-M5 cell lines impairs leukemia motility and delays leukemia propagation (adj. p-value = 2.40e-02), and a number of genes contained in this list are known mediators of cell migration, invasion and transendothelial migration not only in sound tumors but also in haematological malignancies (Physique ?(Figure1A).1A). LGALS1 belongs to the galectins family of beta-galactoside-binding proteins that modulate cell-cell and cell-matrix interactions, its expression correlates with tumor cell motility and invasiveness [31, 32], and is up-regulated in leukemia [33C35]. S100A4 (S100 Calcium-Binding Protein A4) is usually a protein involved in cell motility, invasion, and tubulin polymerization [36]; it is implicated in tumor metastasis [37, 36] and maintenance of KRas G12C inhibitor 4 malignancy stem cells [38]. CAPG is usually a member of the gelsolin/villin family of actin-regulatory proteins that promotes cell migration and is over-expressed in different solid tumors [39, 40]. ITGB2 (integrin beta chain 2) regulates cell adhesion and signaling in combination with different alpha chains, and has been associated with the formation of invadosomes that facilitate leukemia cell invasion through transendothelial migration [41]. CXCR4, the receptor of stromal cell-derived factor-1 (SDF-1), is usually up-regulated in different leukemic contexts and is an important regulator of chemotaxis towards protective niches in the bone marrow [42, 43]. In addition, within the top 10 genes up-regulated in AML-M5, we also found CDKN1A, which encodes a cyclin-dependent kinase inhibitor that promotes maintenance of leukemia stem cells KRas G12C inhibitor 4 [44], and the ZEB2 transcription factor, a grasp regulator of epithelial to mesenchymal transition [45] that also has been implicated in malignancy and leukemia stem cell maintenance [46C48]. In order to validate the data obtained by analysis, we measured the expression of the top up-regulated HIF-1-target genes in main leukemic bone marrow samples from AML KRas G12C inhibitor 4 patients diagnosed and treated at San Raffaele Hospital. Real time PCR analysis confirmed up-regulation of LGALS1, S100A4, CAPG, ITGB2, CDKN1A, ZEB2 and CXCR4 in AML-M5 patients compared with other AML FAB sub-types (Physique ?(Figure2A2A). Open in a separate window Physique 2 Validation of the top up-regulated HIF-1-target genes in AML-M5 cellsA. Real-time PCR analysis of LGALS1, S100A4, CAPG, ITGB2, CDKN1A,.