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Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity
BACKGROUND: Disease relapse remains common following treatment of acute myeloid leukemia (AML) and is due to chemoresistance of leukemia cells with disease repopulating potential. To date, attempts to define the characteristics of in vivo resistant blasts have focused on comparisons between leukemic...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8554867/ https://www.ncbi.nlm.nih.gov/pubmed/34711181 http://dx.doi.org/10.1186/s12885-021-08839-9 |
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author | Williams, Mark S. Basma, Naseer J. Amaral, Fabio M. R. Wiseman, Daniel H. Somervaille, Tim C. P. |
author_facet | Williams, Mark S. Basma, Naseer J. Amaral, Fabio M. R. Wiseman, Daniel H. Somervaille, Tim C. P. |
author_sort | Williams, Mark S. |
collection | PubMed |
description | BACKGROUND: Disease relapse remains common following treatment of acute myeloid leukemia (AML) and is due to chemoresistance of leukemia cells with disease repopulating potential. To date, attempts to define the characteristics of in vivo resistant blasts have focused on comparisons between leukemic cells at presentation and relapse. However, further treatment responses are often seen following relapse, suggesting that most blasts remain chemosensitive. We sought to characterise in vivo chemoresistant blasts by studying the transcriptional and genetic features of blasts from before and shortly after induction chemotherapy using paired samples from six patients with primary refractory AML. METHODS: Leukemic blasts were isolated by fluorescence-activated cell sorting. Fluorescence in situ hybridization (FISH), targeted genetic sequencing and detailed immunophenotypic analysis were used to confirm that sorted cells were leukemic. Sorted blasts were subjected to RNA sequencing. Lentiviral vectors expressing short hairpin RNAs were used to assess the effect of FOXM1 knockdown on colony forming capacity, proliferative capacity and apoptosis in cell lines, primary AML cells and CD34+ cells from healthy donors. RESULTS: Molecular genetic analysis revealed early clonal selection occurring after induction chemotherapy. Immunophenotypic characterisation found leukemia-associated immunophenotypes in all cases that persisted following treatment. Despite the genetic heterogeneity of the leukemias studied, transcriptional analysis found concerted changes in gene expression in resistant blasts. Remarkably, the gene expression signature suggested that post-chemotherapy blasts were more proliferative than those at presentation. Resistant blasts also appeared less differentiated and expressed leukemia stem cell (LSC) maintenance genes. However, the proportion of immunophenotypically defined LSCs appeared to decrease following treatment, with implications for the targeting of these cells on the basis of cell surface antigen expression. The refractory gene signature was highly enriched with targets of the transcription factor FOXM1. shRNA knockdown experiments demonstrated that the viability of primary AML cells, but not normal CD34+ cells, depended on FOXM1 expression. CONCLUSIONS: We found that chemorefractory blasts from leukemias with varied genetic backgrounds expressed a common transcriptional program. In contrast to the notion that LSC quiescence confers resistance to chemotherapy we find that refractory blasts are both actively proliferating and enriched with LSC maintenance genes. Using primary patient material from a relevant clinical context we also provide further support for the role of FOXM1 in chemotherapy resistance, proliferation and stem cell function in AML. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-021-08839-9. |
format | Online Article Text |
id | pubmed-8554867 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-85548672021-10-29 Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity Williams, Mark S. Basma, Naseer J. Amaral, Fabio M. R. Wiseman, Daniel H. Somervaille, Tim C. P. BMC Cancer Research Article BACKGROUND: Disease relapse remains common following treatment of acute myeloid leukemia (AML) and is due to chemoresistance of leukemia cells with disease repopulating potential. To date, attempts to define the characteristics of in vivo resistant blasts have focused on comparisons between leukemic cells at presentation and relapse. However, further treatment responses are often seen following relapse, suggesting that most blasts remain chemosensitive. We sought to characterise in vivo chemoresistant blasts by studying the transcriptional and genetic features of blasts from before and shortly after induction chemotherapy using paired samples from six patients with primary refractory AML. METHODS: Leukemic blasts were isolated by fluorescence-activated cell sorting. Fluorescence in situ hybridization (FISH), targeted genetic sequencing and detailed immunophenotypic analysis were used to confirm that sorted cells were leukemic. Sorted blasts were subjected to RNA sequencing. Lentiviral vectors expressing short hairpin RNAs were used to assess the effect of FOXM1 knockdown on colony forming capacity, proliferative capacity and apoptosis in cell lines, primary AML cells and CD34+ cells from healthy donors. RESULTS: Molecular genetic analysis revealed early clonal selection occurring after induction chemotherapy. Immunophenotypic characterisation found leukemia-associated immunophenotypes in all cases that persisted following treatment. Despite the genetic heterogeneity of the leukemias studied, transcriptional analysis found concerted changes in gene expression in resistant blasts. Remarkably, the gene expression signature suggested that post-chemotherapy blasts were more proliferative than those at presentation. Resistant blasts also appeared less differentiated and expressed leukemia stem cell (LSC) maintenance genes. However, the proportion of immunophenotypically defined LSCs appeared to decrease following treatment, with implications for the targeting of these cells on the basis of cell surface antigen expression. The refractory gene signature was highly enriched with targets of the transcription factor FOXM1. shRNA knockdown experiments demonstrated that the viability of primary AML cells, but not normal CD34+ cells, depended on FOXM1 expression. CONCLUSIONS: We found that chemorefractory blasts from leukemias with varied genetic backgrounds expressed a common transcriptional program. In contrast to the notion that LSC quiescence confers resistance to chemotherapy we find that refractory blasts are both actively proliferating and enriched with LSC maintenance genes. Using primary patient material from a relevant clinical context we also provide further support for the role of FOXM1 in chemotherapy resistance, proliferation and stem cell function in AML. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-021-08839-9. BioMed Central 2021-10-28 /pmc/articles/PMC8554867/ /pubmed/34711181 http://dx.doi.org/10.1186/s12885-021-08839-9 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. |
spellingShingle | Research Article Williams, Mark S. Basma, Naseer J. Amaral, Fabio M. R. Wiseman, Daniel H. Somervaille, Tim C. P. Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title | Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title_full | Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title_fullStr | Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title_full_unstemmed | Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title_short | Blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of FOXM1 activity |
title_sort | blast cells surviving acute myeloid leukemia induction therapy are in cycle with a signature of foxm1 activity |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8554867/ https://www.ncbi.nlm.nih.gov/pubmed/34711181 http://dx.doi.org/10.1186/s12885-021-08839-9 |
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