Project description:Acute Myeloid Leukemia (AML) represents a heterogeneous group of hematological malignancies. The t(6;9)(p23;q34) translocation, giving rise to the DEK::NUP214 fusion protein, is a rare mutation which produces a highly aggressive AML associated with extremely poor prognosis. Here, we utilise genome-wide chromatin accessibility to elucidate how a normal gene regulatory networks is disrupted by DEK::NUP214. We find that DEK::NUP214 AML forms a specific GRN related to that of mutant NPM1 AML, but also displays an elevated leukemic stem cell signature, suggesting both similar and unique therapeutic vulnerabilities.
Project description:Acute Myeloid Leukemia (AML) represents a heterogeneous group of hematological malignancies. The t(6;9)(p23;q34) translocation, giving rise to the DEK::NUP214 fusion protein, is a rare mutation which produces a highly aggressive AML associated with extremely poor prognosis. Here, we utilise genome-wide chromatin accessibility to elucidate how a normal gene regulatory networks is disrupted by DEK::NUP214. We find that DEK::NUP214 AML forms a specific GRN related to that of mutant NPM1 AML, but also displays an elevated leukemic stem cell signature, suggesting both similar and unique therapeutic vulnerabilities.
Project description:Aberrant and constitutive activation of the clustered homeobox (HOX) genes and the three-amino-acid loop extension (TALE) domain-containing HOX co-factor MEIS1 (henceforth termed HOX/MEIS) is a recurrent feature in several types of myeloid and lymphoid leukemias. HOX/MEIS misexpression is linked to aberrant self-renewal and therapy resistance in leukemia, but the therapeutic targeting of this important pathway has remained elusive. Using AF10-rearranged leukemia as a prototypical example of HOX/MEIS dysregulation, we sought to comprehensively characterize chromatin regulators that sustain aberrant expression of these genes. We deployed a GFP-MEIS1 knock-in reporter cell line to conduct small-molecule inhibitor screens and a high-density domain-focused CRISPR-Cas9 screen targeting epigenetic regulators. We identified members of at least six distinct chromatin-modifying complexes as HOX/MEIS regulators, including previously characterized HOX/MEIS regulators such as DOT1L, AF10, ENL, and HBO1 as well as less well-characterized and completely novel HOX/MEIS regulators including AFF2, JADE3, casein kinase 2 and the chromatin reader SGF29. These HOX/MEIS regulators were important for the growth of AML cell lines representing diverse leukemia subtypes characterized by HOX/MEIS dysregulation including leukemias with AF10 rearrangements, MLL rearrangements, and NPM1 mutation. Determination of gene expression changes after perturbing each of these MEIS1 regulators in parallel using CROP-seq demonstrated that the deletion of DOT1L, ENL, AFF2, or SGF29 led to the downregulation of several genes associated with stem cell self-renewal and upregulation of differentiation-associated genes.
Project description:AML with mutated NPM1 usually carries normal karyotype (NK) but it may harbor chromosomal aberrations whose significance remains unclear. We addressed this question in 631 AML patients with mutated/cytoplasmic NPM1. An abnormal karyotype (AK) was present in 93/631 cases (14.7%), the most frequent abnormalities being +8, +4, -Y, del(9q), +21. Chromosome aberrations in NPM1-mutated AML were similar to, but occurred less frequently than additional chromosome changes found in other AML with recurrent cytogenetic abnormalities according to WHO classification. Four of the 31 NPM1-mutated AML patients karyotyped at different time points had NK at diagnosis but AK at relapse: del(9q) (n=2), t(2;11) (n=1), inv(12) (n=1). NPM1-mutated AML with NK or AK showed overlapping morphological, immunophenotypic (CD34-negativity) and gene expression profile (downregulation of CD34 and upregulation of HOX genes). No difference in survival was observed among NPM1-mutated AML patients independently of whether they carried a normal or abnormal karyotype, the NPM1-mutated/FLT3-ITD negative cases showing the better prognosis. Findings in our patients point to chromosomal aberrations as secondary events, reinforce the concept that NPM1 mutation is a founder genetic lesion and indicate that NPM1-mutated AML should be clinically handled as one entity, irrespective of the karyotype. All bone marrow samples were obtained from untreated patients at the time of diagnosis. Cells used for microarray analysis were collected from the purified fraction of mononuclear cells after Ficoll density centrifugation.
Project description:Somatic mutations in cancer are a potential source of cancer specific neoantigens. Acute myeloid leukemia (AML) has common recurrent mutations shared between patients in addition to private mutations specific to individuals. We hypothesized that neoantigens derived from recurrent shared mutations would be attractive targets for future immunotherapy and sought to study the Class I and II HLA ligandomes of thirteen primary AML tumor samples and two AML cell lines (OCI-AML3 and MV4-11) using mass spectrometry. We identified two endogenous, mutation-bearing HLA Class I ligands from NPM1, which are predicted to bind the common HLA haplotypes, HLA-A*03:01 and HLA-A*02:01 respectively. We further derived CD8+ T cells from healthy donor peripheral blood samples which bound mutant-peptide loaded A*03:01 and A*02:01 tetramers, suggesting a new source of NPM1 mutation-specific T cell receptors (TCRs) for future evaluation. Since NPM1 is mutated in approximately one-third of patients with AML, the finding of endogenous NPM1 neoantigens supports future studies evaluating immunotherapeutic approaches against this target, for this subset of patients with AML.
Project description:AML with mutated NPM1 usually carries normal karyotype (NK) but it may harbor chromosomal aberrations whose significance remains unclear. We addressed this question in 631 AML patients with mutated/cytoplasmic NPM1. An abnormal karyotype (AK) was present in 93/631 cases (14.7%), the most frequent abnormalities being +8, +4, -Y, del(9q), +21. Chromosome aberrations in NPM1-mutated AML were similar to, but occurred less frequently than additional chromosome changes found in other AML with recurrent cytogenetic abnormalities according to WHO classification. Four of the 31 NPM1-mutated AML patients karyotyped at different time points had NK at diagnosis but AK at relapse: del(9q) (n=2), t(2;11) (n=1), inv(12) (n=1). NPM1-mutated AML with NK or AK showed overlapping morphological, immunophenotypic (CD34-negativity) and gene expression profile (downregulation of CD34 and upregulation of HOX genes). No difference in survival was observed among NPM1-mutated AML patients independently of whether they carried a normal or abnormal karyotype, the NPM1-mutated/FLT3-ITD negative cases showing the better prognosis. Findings in our patients point to chromosomal aberrations as secondary events, reinforce the concept that NPM1 mutation is a founder genetic lesion and indicate that NPM1-mutated AML should be clinically handled as one entity, irrespective of the karyotype.
Project description:Abstract Mutations in the gene encoding nucleophosmin (NPM1) carry prognostic value for patients with acute myeloid leukemia (AML). Various techniques are currently being used to detect these mutations in routine molecular diagnostics. Incorporation of accurate NPM1 mutation detection on a gene expression platform would enable simultaneous detection with various other expression biomarkers. Here we present an array based mutation detection using custom probes for NPM1 WT mRNA and NPM1 type A, B, and D mutant mRNA. This method was 100% accurate on a training cohort of 505 newly diagnosed unselected AML cases. Validation on an independent cohort of 143 normal karyotype AML cases revealed no false negative results, and one false positive (sensitivity 100.0%, and specificity 98.7%). Based on this, we conclude that this method provides a reliable method for NPM1 mutation detection. The method can be applied to other genes/mutations as long as the mutant alleles are sufficiently high expressed. Validation cohort of 143 AML cases analyzed using the AMLprofiler
Project description:Abstract Mutations in the gene encoding nucleophosmin (NPM1) carry prognostic value for patients with acute myeloid leukemia (AML). Various techniques are currently being used to detect these mutations in routine molecular diagnostics. Incorporation of accurate NPM1 mutation detection on a gene expression platform would enable simultaneous detection with various other expression biomarkers. Here we present an array based mutation detection using custom probes for NPM1 WT mRNA and NPM1 type A, B, and D mutant mRNA. This method was 100% accurate on a training cohort of 505 newly diagnosed unselected AML cases. Validation on an independent cohort of 143 normal karyotype AML cases revealed no false negative results, and one false positive (sensitivity 100.0%, and specificity 98.7%). Based on this, we conclude that this method provides a reliable method for NPM1 mutation detection. The method can be applied to other genes/mutations as long as the mutant alleles are sufficiently high expressed. Training cohort of 505 AML cases analyzed using the AMLprofiler