Project description:Nucleophosmin mutated AML (NPM1mut-AML) patients have a high rate of complete remission (CR) to induction chemotherapy. However, the mechanisms responsible for such effects are unknown. Since miR-10 family members are expressed at high levels in NPM1mut-AML, we evaluated whether these microRNAs could predict chemotherapy response in AML. We found that high baseline miR-10 family expression in 54 untreated cytogenetically heterogeneous AML patients was associated with achieving CR. However, when we included NPM1 mutation status in the multivariable model, there was a significant interaction effect between miR-10a-5p expression and NPM1 mutation status. Similar results were observed when using a second cohort of 183 cytogenetically normal older (ageM-bM-^IM-%60 years) AML patients. Loss and gain of function experiments using miR-10a-5p in cell lines and primary blasts did not demonstrate any effect in apoptosis or cell proliferation at baseline or after chemotherapy. These data support a bystander role for the miR-10 family in NPM1mut-AML. Pretreatment miRNA expression was analyzed in 54 de novo adult AML patients obtained from the MD Anderson Cancer Center Leukemia Tissue Bank (LTB) using the Ohio State University (OSU) miRNA microarray (ver.3).
Project description:Nucleophosmin mutated AML (NPM1mut-AML) patients have a high rate of complete remission (CR) to induction chemotherapy. However, the mechanisms responsible for such effects are unknown. Since miR-10 family members are expressed at high levels in NPM1mut-AML, we evaluated whether these microRNAs could predict chemotherapy response in AML. We found that high baseline miR-10 family expression in 54 untreated cytogenetically heterogeneous AML patients was associated with achieving CR. However, when we included NPM1 mutation status in the multivariable model, there was a significant interaction effect between miR-10a-5p expression and NPM1 mutation status. Similar results were observed when using a second cohort of 183 cytogenetically normal older (age≥60 years) AML patients. Loss and gain of function experiments using miR-10a-5p in cell lines and primary blasts did not demonstrate any effect in apoptosis or cell proliferation at baseline or after chemotherapy. These data support a bystander role for the miR-10 family in NPM1mut-AML.
Project description:Multilineage dysplasia (MLD) has no impact on biological, clinico-pathological and prognostic features of AML with mutated nucleophosmin (NPM1) NPM1-mutated AML is a provisional entity in the WHO-2008 classification of myeloid neoplasms. The significance of concomitant multilineage dysplasia (MLD) in NPM1-mutated AML is unclear. Thus, in the WHO-2008 classification, NPM1-mutated AML with MLD is classified as AML with myelodysplasia(MD)-related changes. We evaluated the MLD impact in 378 NPM1-mutated AML patients. MLD was found in about 25% cases. Except for a lower WBC and FLT3-ITD incidence in MLD+ group, no significant differences were observed in age, sex, cytogenetics and FLT3-TKD between NPM1-mutated AML with and without MLD. Notably, NPM1-mutated AML with/without MLD showed overlapping immunophenotype (CD34-negativity) and GEP (CD34 downregulation and HOX genes upregulation). Moreover, OS and EFS did not differ among NPM1-mutated AML patients, independently of whether they carried or not MLD, the NPM1-mutated/FLT3-ITD negative cases showing the better prognosis. Lack of MLD impact on survival was confirmed by multivariate analysis that highlighted FLT3-ITD as the most significant prognostic parameter in NPM1-mutated AML. Our findings indicate that NPM1 mutations rather than MLD dictate the distinctive features of NPM1-mutated AML. Thus, irrespective of MLD, NPM1-mutated AML should be considered as one disease entity clearly distinct from AML with MD-related changes. These findings have important diagnostic and prognostic implications in AML. 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. 48 samples
Project description:Multilineage dysplasia (MLD) has no impact on biological, clinico-pathological and prognostic features of AML with mutated nucleophosmin (NPM1) NPM1-mutated AML is a provisional entity in the WHO-2008 classification of myeloid neoplasms. The significance of concomitant multilineage dysplasia (MLD) in NPM1-mutated AML is unclear. Thus, in the WHO-2008 classification, NPM1-mutated AML with MLD is classified as AML with myelodysplasia(MD)-related changes. We evaluated the MLD impact in 378 NPM1-mutated AML patients. MLD was found in about 25% cases. Except for a lower WBC and FLT3-ITD incidence in MLD+ group, no significant differences were observed in age, sex, cytogenetics and FLT3-TKD between NPM1-mutated AML with and without MLD. Notably, NPM1-mutated AML with/without MLD showed overlapping immunophenotype (CD34-negativity) and GEP (CD34 downregulation and HOX genes upregulation). Moreover, OS and EFS did not differ among NPM1-mutated AML patients, independently of whether they carried or not MLD, the NPM1-mutated/FLT3-ITD negative cases showing the better prognosis. Lack of MLD impact on survival was confirmed by multivariate analysis that highlighted FLT3-ITD as the most significant prognostic parameter in NPM1-mutated AML. Our findings indicate that NPM1 mutations rather than MLD dictate the distinctive features of NPM1-mutated AML. Thus, irrespective of MLD, NPM1-mutated AML should be considered as one disease entity clearly distinct from AML with MD-related changes. These findings have important diagnostic and prognostic implications in AML.
Project description:Acute myeloid leukemia is characterized by a minor fraction of primitive leukemia stem cells (LSCs) that sustain disease propagation and may be at the origin of late relapse. Yet, LSC contribution to early therapy resistance and AML regeneration remains controversial. We prospectively identified LSCs in NPM1-mutated AML patients and xenografts by means of a microRNA-126 reporter and single cell RNA sequencing, precisely discriminating LSCs from regenerating hematopoiesis, and assessed their longitudinal response to chemotherapy. We here show that chemotherapy resulted in distinct outcomes within AML subpopulations: while the bulk leukemia proliferated and differentiated with expression of oxidative-phosphorylation signatures, persisting miR-126high LSCs enforced protective stemness and dormancy features, along with a generalized inflammatory and senescence-associated response. miR-126high LSCs were enriched at diagnosis in patients with chemotherapy-refractory AML. We derived a novel miR-126high LSC transcriptional signature, which robustly stratified patients for overall survival in large AML cohorts, shining the spotlight on LSCs as determinants of early therapy resistance.
Project description:Acute myeloid leukemia is characterized by a minor fraction of primitive leukemia stem cells (LSCs) that sustain disease propagation and may be at the origin of late relapse. Yet, LSC contribution to early therapy resistance and AML regeneration remains controversial. We prospectively identified LSCs in NPM1-mutated AML patients and xenografts by means of a microRNA-126 reporter and single cell RNA sequencing, precisely discriminating LSCs from regenerating hematopoiesis, and assessed their longitudinal response to chemotherapy. We here show that chemotherapy resulted in distinct outcomes within AML subpopulations: while the bulk leukemia proliferated and differentiated with expression of oxidative-phosphorylation signatures, persisting miR-126high LSCs enforced protective stemness and dormancy features, along with a generalized inflammatory and senescence-associated response. miR-126high LSCs were enriched at diagnosis in patients with chemotherapy-refractory AML. We derived a novel miR-126high LSC transcriptional signature, which robustly stratified patients for overall survival in large AML cohorts, shining the spotlight on LSCs as determinants of early therapy resistance.
Project description:Acute myeloid leukemia is characterized by a minor fraction of primitive leukemia stem cells (LSCs) that sustain disease propagation and may be at the origin of late relapse. Yet, LSC contribution to early therapy resistance and AML regeneration remains controversial. We prospectively identified LSCs in NPM1-mutated AML patients and xenografts by means of a microRNA-126 reporter and single cell RNA sequencing, precisely discriminating LSCs from regenerating hematopoiesis, and assessed their longitudinal response to chemotherapy. We here show that chemotherapy resulted in distinct outcomes within AML subpopulations: while the bulk leukemia proliferated and differentiated with expression of oxidative-phosphorylation signatures, persisting miR-126high LSCs enforced protective stemness and dormancy features, along with a generalized inflammatory and senescence-associated response. miR-126high LSCs were enriched at diagnosis in patients with chemotherapy-refractory AML. We derived a novel miR-126high LSC transcriptional signature, which robustly stratified patients for overall survival in large AML cohorts, shining the spotlight on LSCs as determinants of early therapy resistance.
Project description:Acute myeloid leukemia (AML) carrying NPM1 mutations and cytoplasmic nucleophosmin (NPMc+ AML) accounts for about one-third of adult AML and shows distinct features, including a unique gene expression profile. MicroRNAs (miRNAs) are small noncoding RNAs of 19-25 nucleotides in length that have been linked to the development of cancer. Here, we investigated the role of miRNAs in the biology of NPMc+ AML. The miRNA expression was evaluated in 85 adult de novo AML patients characterized for subcellular localization/mutation status of NPM1 and FLT3 mutations using a custom microarray platform. Data were analyzed by using univariate t test within BRB tools. We identified a strong miRNA signature that distinguishes NPMc+ mutated (n = 55) from the cytoplasmic-negative (NPM1 unmutated) cases (n = 30) and includes the up-regulation of miR-10a, miR-10b, several let-7 and miR-29 family members. Many of the down-regulated miRNAs including miR-204 and miR-128a are predicted to target several HOX genes. Indeed, we confirmed that miR-204 targets HOXA10 and MEIS1, suggesting that the HOX up-regulation observed in NPMc+ AML may be due in part by loss of HOX regulators-miRNAs. FLT3-ITD+ samples were characterized by up-regulation of miR-155. Further experiments demonstrated that the up-regulation of miR-155 was independent from FLT3 signaling. Our results identify a unique miRNA signature associated with NPMc+ AML and provide evidence that support a role for miRNAs in the regulation of HOX genes in this leukemia subtype. Moreover, we found that miR-155 was strongly but independently associated with FLT3-ITD mutations.
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: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.