Project description:Molm13 AML cell line both control and MPI KO, treated with AC220 (quizartinib) and mannose at 24 and 72 hours after drug treatment. 2 reads and 2 repeats for each condition, 2 timepoints, 48 total files.
Project description:FLT3 is a receptor tyrosine kinase that is frequently mutated in AML. Inhibition of FLT3 induces myeloid differentiation in AML patients. We identified a role of FLT3 inhibition in decreasing EZH2 expression. To assess the impact of this regulation on PRC2 function, we performed H3K27me3 ChIP-Seq in a FLT3 mutated human AML cell line.
Project description:The FLT3-ITD mutation is associated with poor prognosis in acute myeloid leukemia (AML). FLT3 tyrosine kinase inhibitors (TKIs) demonstrate clinical efficacy but fail to target leukemia stem cells (LSC) and do not generate sustained responses. Autophagy is an important cellular stress response contributing to hematopoietic stem cells (HSC) maintenance and promoting leukemia development. Here we investigated the role of autophagy in regulating FLT3-ITD AML stem cell function and response to TKI treatment. We show that autophagy inhibition reduced quiescence and depleted repopulating potential of FLT3-ITD AML LSC, associated with mitochondrial accumulation and increased oxidative phosphorylation. However, TKI treatment reduced mitochondrial respiration and unexpectedly antagonized the effects of autophagy inhibition on LSC attrition. We further show that TKI-mediated targeting of AML LSC and committed progenitors was p53-dependent, and that autophagy inhibition enhanced p53 activity and increased TKI-mediated targeting of AML progenitors, but decreased p53 activity in LSC and reduced TKI-mediated LSC inhibition. These results provide new insights into the role of autophagy in differentially regulating AML stem and progenitor cells, reveal unexpected antagonistic effects of combined oncogenic tyrosine kinase inhibition and autophagy inhibition in AML LSC, and suggest an alternative approach to target AML LSC quiescence and regenerative potential.
Project description:FLT3ITD are common mutations in Acute Myeloid Leukemia (AML) and carry a particularly bad prognosis. Although new generation FLT3 tyrosine kinase inhibitors (TKI) have shown promising results, the outcome of FLT3-mutated AML patients remains poor and demands the identification of novel, specific and validated therapeutic targets for this highly aggressive AML subtype. Utilizing an unbiased genome-wide CRISPR/Cas9 screen, we identify GLS, the first enzyme in glutamine metabolism, as synthetically lethal with FLT3 TKI treatment. Using complementary metabolomic and gene-expression analysis, we demonstrate that glutamine metabolism, through its ability to support both mitochondrial function and cellular redox metabolism, becomes a metabolic dependency of FLT3ITD AML, specifically unmasked by FLT3-TKI treatment. We extend these findings to AML subtypes driven by other tyrosine kinase activating mutations, and validate the role of GLS as a clinically actionable therapeutic target in both primary AML and in vivo models. Our work highlights the role of metabolic adaptations as a resistance mechanism to several TKI inhibitors, and suggests glutaminolysis as a therapeutically targetable vulnerability when combined with specific TKI in FLT3ITD and other TK activating mutation driven leukemias.
Project description:Fms-like tyrosine kinase 3 (Flt3) is a regulator of hematopoietic progenitor cells. It is a target of tyrosine kinase inhibitors (TKIs) used for acute myeloid leukemia treatment. Flt3 and its ligand (Flt3L) are expressed in the heart and cardiac side effects occur under Flt3-targeting TKIs. Whether Flt3/Flt3L also regulate cardiac progenitor cells (CPCs), however, is not known. The cardiac side population (SP) is a pool of heterogenous CPCs that can give rise to all cardiac lineages, hence contributing to cardiovascular homeostasis. Here we show that SP-CPCs produce and are responsive to Flt3L. Compared to wild-type, SP-CPCs from flt3L-/- mice are less abundant, with less contribution of CD45-CD34+ cells, and lower expression of gene sets related to epithelial-to-mesenchymal transition, cardiovascular development and stem cell differentiation. Upon culturing and compared to wild-type, flt3L-/- Sca1+CD31- SP-CPCs show increased proliferation and less vasculogenic commitment, but differentiation can be induced in the presence of receptor tyrosine kinase-activating growth factors. The observed differences are associated with decreased microvascularisation and global systolic function of flt3L-/- hearts. Thus, Flt3 contributes to a receptor tyrosine kinase signature necessary for the maintenance and functionality of SP-CPCs. These findings have potential implications regarding cardiovascular side effects observed under TKI therapy.
Project description:In this study, we screened a group of newly synthesized tyrosine kinase inhibitors, and discovered MZH29 was a potent FLT3 inhibitor. Remarkably, MZH29 is well tolerated and effective in the clinically known FLT3 mutants in the constructed BaF3 model cells. MZH29 could also lead to complete tumor regression in the mouse xenograft model and increases survival in the bone marrow engraftment model. Further proteomics study indicates that the inhibition effects of MZH29 and AC220 are in a similar manner. All the results present here support that MZH29 could be a promising candidate for both the FLT3 WT and drug resistance mutant AML.
Project description:Kinase hyperactivity is a common driver of acute myeloid leukemia (AML) and serves as a therapeutic target. The most frequent genetic aberration leading to hyperactive kinase signaling and poor prognosis is internal tandem duplication (ITD) of the FMS-tyrosine-like Kinase 3-gene (FLT3). FLT3-ITD induces ligand independent activation of FLT3 and downstream pathways leading to proliferation, decreased apoptosis and partial differentiation block. Combined with chemotherapy, FLT3-Tyrosine Kinase Inhibitor (FLT3-TKI) midostaurin improves overall survival (OS) of newly diagnosed FLT3-mutated AML patients, whereas single agent gilteritinib proved superior to chemotherapy in relapsed/refractory FLT3-mutated AML patients . As the primary targets of currently approved FLT3-TKIs are tyrosine (Y) kinases, we hypothesized that direct evaluation of tyrosine phosphorylation status could reveal pY phosphorylation profiles associated with FLT3-TKI response. Therefore, we used label-free pTyr-based phosphoproteomics in 35 primary AML samples (18 FLT3-WT, 17 FLT3-ITD), to identify differentially phosphorylated proteins underlying response to the FLT3-TKIs gilteritinib and midostaurin. We identified a total of 3024 unique phosphosites (median 1299 per sample, range 286 – 1612, pS:pT:pY 11.9%:9.5%:78.6%). Due to low number of identified phosphosites, we excluded two samples from further analyses. On the remaining 33 samples, we additionally performed IMAC global phosphoproteomics and on 17 samples protein expression analysis.
Project description:Constitutively activating internal tandem duplication (ITD) alterations of the receptor tyrosine kinase FLT3 (Fms-like tyrosine kinase 3) are common in acute myeloid leukemia (AML) and classifies FLT3 as an attractive therapeutic target. So far, application of FLT3 small molecule inhibitors such as Sorafenib has resulted only in partial and transient clinical responses in FLT3-ITD+ patients. Only recently, a prolonged event-free survival has been observed in AML patients who were treated with Sorafenib in addition to standard therapy. Here, we studied the Sorafenib effect on proliferation in a panel of 13 FLT3-ITD- and FLT3-ITD+ AML cell lines. Sorafenib IC50 values ranged from 0.001 to 5.6 µM, whereas FLT3-ITD+ cells (MOLM-13, MV4;11) were found more sensitive to Sorafenib than FLT3-ITD- cells. However, we identified two FLT3-ITD- cell lines (MONO-MAC-1 and OCI-AML-2) which were also Sorafenib sensitive. Phosphoproteome analyses revealed that the affected pathways differed in Sorafenib sensitive FLT3-ITD- and FLT3-ITD+ cells. In MV4;11 cells Sorafenib suppressed mTOR signalling by inhibiting direct inhibition of FLT3. In MONO-MAC-1 cells Sorafenib inhibited the MEK/ERK pathway by inhibition of the RET tyrosine kinase. These data suggest that the FLT3 status in AML patients might not be the only predictive factor for a response to Sorafenib.
Project description:Acute myeloid leukemia with normal karyotype (NK-AML) represents a cytogenetic grouping with intermediate prognosis but substantial molecular and clinical heterogeneity. Within this subgroup, presence of FLT3 (FMS-like tyrosine kinase 3) internal tandem duplication (ITD) mutation predicts less favorable outcome. The goal of our study was to discover gene-expression patterns correlated with FLT3-ITD mutation, and to evaluate the utility of a FLT3 signature for prognostication. The dataset comprises gene-expression profiles of 137 normal karyotype acute myeloid leukemia (NK-AML) specimens carried out using Stanford cDNA microarrays, to accompany the study of L Bullinger et al. For each array, Channel 2 represents Cy5-labeled NK-AML RNA, and Channel 1 Cy3-labeled universal reference RNA. Keywords: Logical Set DNA microarrays were used to profile gene expression in a training set of 65 NK-AML cases. Supervised analysis was applied to build a gene expression-based predictor of FLT3-ITD mutation status. The predictor was then evaluated by classifying expression profiles from an independent test set of 72 NK-AML cases.
Project description:This data set was used to study FLT3 wild type and mutants in childhood AML samples from the Pediatric Oncology Group Study 9421. Abstract: Fms-like tyrosine kinase 3 (FLT3) mutations are associated with unfavorable outcomes in children with acute myeloid leukemia (AML). We used DNA microarrays to identify gene expression profiles related to FLT3 status and outcome in childhood AML. Among 81 diagnostic specimens, 36 had FLT3 mutations (FLT3-MUs), 24 with internal tandem duplications (ITDs) and 12 with activating loop mutations (ALMs). In addition, 8 of 19 specimens from patients with relapses had FLT3-MUs. Predictive analysis of microarrays (PAM) identified genes that differentiated FLT3-ITD from FLT3-ALM and FLT3 wild-type (FLT3-WT) cases. Among the 42 specimens with FLT3-MUs, PAM identified 128 genes that correlated with clinical outcome. Event-free survival (EFS) in FLT3-MU patients with a favorable signature was 45% versus 5% for those with an unfavorable signature (P = .018). Among FLT3-MU specimens, high expression of the RUNX3 gene and low expression of the ATRX gene were associated with inferior outcome. The ratio of RUNX3 to ATRX expression was used to classify FLT3-MU cases into 3 EFS groups: 70%, 37%, and 0% for low, intermediate, and high ratios, respectively (P < .0001). Thus, gene expression profiling identified AML patients with divergent prognoses within the FLT3-MU group, and the RUNX3 to ATRX expression ratio should be a useful prognostic indicator in these patients. A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Computed