Acute myeloid leukemia (AML) is an aggressive cancer with a poor prognosis, for which mainstream treatments have not changed for decades. To identify additional therapeutic targets in AML, we ...optimize a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screening platform and use it to identify genetic vulnerabilities in AML cells. We identify 492 AML-specific cell-essential genes, including several established therapeutic targets such as DOT1L, BCL2, and MEN1, and many other genes including clinically actionable candidates. We validate selected genes using genetic and pharmacological inhibition, and chose KAT2A as a candidate for downstream study. KAT2A inhibition demonstrated anti-AML activity by inducing myeloid differentiation and apoptosis, and suppressed the growth of primary human AMLs of diverse genotypes while sparing normal hemopoietic stem-progenitor cells. Our results propose that KAT2A inhibition should be investigated as a therapeutic strategy in AML and provide a large number of genetic vulnerabilities of this leukemia that can be pursued in downstream studies.
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•Optimized CRISPR platform for identification of genome-wide genetic vulnerabilities•Catalog of genetic vulnerabilities in acute myeloid leukemia cell lines•KAT2A inhibition induces myeloid differentiation and apoptosis•KAT2A inhibition arrests the growth of primary AML cells, but not of normal progenitors
Tzelepis et al. optimize a CRISPR-Cas9-based platform for the performance of genome-wide recessive screens and apply it to identify genetic vulnerabilities of human AML cells. They identify several known therapeutic targets including BRD4, DOT1L, and MEN1, and numerous additional candidates. They provide data proposing KAT2A as a potential therapeutic target.
Clonal hemopoiesis driven by leukemia-associated gene mutations can occur without evidence of a blood disorder. To investigate this phenomenon, we interrogated 15 mutation hot spots in blood DNA from ...4,219 individuals using ultra-deep sequencing. Using only the hot spots studied, we identified clonal hemopoiesis in 0.8% of individuals under 60, rising to 19.5% of those ≥90 years, thus predicting that clonal hemopoiesis is much more prevalent than previously realized. DNMT3A-R882 mutations were most common and, although their prevalence increased with age, were found in individuals as young as 25 years. By contrast, mutations affecting spliceosome genes SF3B1 and SRSF2, closely associated with the myelodysplastic syndromes, were identified only in those aged >70 years, with several individuals harboring more than one such mutation. This indicates that spliceosome gene mutations drive clonal expansion under selection pressures particular to the aging hemopoietic system and explains the high incidence of clonal disorders associated with these mutations in advanced old age.
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•Clonal hemopoiesis is an almost inevitable consequence of aging in humans•Spliceosome gene mutations drove clonal hemopoiesis only in persons aged ≥70 years•NPM1 mutations behave as gatekeepers for leukemogenesis
McKerrell et al. employ ultra-deep sequencing to show that age-related clonal hemopoiesis is much more common than previously realized. They find that clonal hemopoiesis, driven by mutations in spliceosome genes SF3B1 and SRSF2, was noted exclusively in individuals aged 70 years or older and that NPM1 mutations are not seen in association with this phenomenon, endorsing their close association with leukemogenesis.
T-Cell Cancer after CAR T-Cell Therapy Mitchell, Emily; Vassiliou, George S.
The New England journal of medicine,
06/2024, Letnik:
390, Številka:
22
Journal Article
Recenzirano
The last three decades have seen dramatic advances in the use of immunotherapies to treat cancer, primarily in the form of monoclonal antibodies targeting cancer cells directly or recruiting the ...immune system against them. More recently, immune cells themselves are being used as anticancer treatments, led by chimeric antigen receptor (CAR) T cells, genetically modified autologous T cells that are manufactured to express a CAR gene. CAR genes are engineered to code for a transmembrane protein with an extracellular antigen recognition and intracellular T-cell–activating domains that enable CAR T cells to recognize and attack cancer cells that express its target . . .
Age-related change in human haematopoiesis causes reduced regenerative capacity
, cytopenias
, immune dysfunction
and increased risk of blood cancer
, but the reason for such abrupt functional ...decline after 70 years of age remains unclear. Here we sequenced 3,579 genomes from single cell-derived colonies of haematopoietic cells across 10 human subjects from 0 to 81 years of age. Haematopoietic stem cells or multipotent progenitors (HSC/MPPs) accumulated a mean of 17 mutations per year after birth and lost 30 base pairs per year of telomere length. Haematopoiesis in adults less than 65 years of age was massively polyclonal, with high clonal diversity and a stable population of 20,000-200,000 HSC/MPPs contributing evenly to blood production. By contrast, haematopoiesis in individuals aged over 75 showed profoundly decreased clonal diversity. In each of the older subjects, 30-60% of haematopoiesis was accounted for by 12-18 independent clones, each contributing 1-34% of blood production. Most clones had begun their expansion before the subject was 40 years old, but only 22% had known driver mutations. Genome-wide selection analysis estimated that between 1 in 34 and 1 in 12 non-synonymous mutations were drivers, accruing at constant rates throughout life, affecting more genes than identified in blood cancers. Loss of the Y chromosome conferred selective benefits in males. Simulations of haematopoiesis, with constant stem cell population size and constant acquisition of driver mutations conferring moderate fitness benefits, entirely explained the abrupt change in clonal structure in the elderly. Rapidly decreasing clonal diversity is a universal feature of haematopoiesis in aged humans, underpinned by pervasive positive selection acting on many more genes than currently identified.
Clonal expansions driven by somatic mutations become pervasive across human tissues with age, including in the haematopoietic system, where the phenomenon is termed clonal haematopoiesis
. The ...understanding of how and when clonal haematopoiesis develops, the factors that govern its behaviour, how it interacts with ageing and how these variables relate to malignant progression remains limited
. Here we track 697 clonal haematopoiesis clones from 385 individuals 55 years of age or older over a median of 13 years. We find that 92.4% of clones expanded at a stable exponential rate over the study period, with different mutations driving substantially different growth rates, ranging from 5% (DNMT3A and TP53) to more than 50% per year (SRSF2
). Growth rates of clones with the same mutation differed by approximately ±5% per year, proportionately affecting slow drivers more substantially. By combining our time-series data with phylogenetic analysis of 1,731 whole-genome sequences of haematopoietic colonies from 7 individuals from an older age group, we reveal distinct patterns of lifelong clonal behaviour. DNMT3A-mutant clones preferentially expanded early in life and displayed slower growth in old age, in the context of an increasingly competitive oligoclonal landscape. By contrast, splicing gene mutations drove expansion only later in life, whereas TET2-mutant clones emerged across all ages. Finally, we show that mutations driving faster clonal growth carry a higher risk of malignant progression. Our findings characterize the lifelong natural history of clonal haematopoiesis and give fundamental insights into the interactions between somatic mutation, ageing and clonal selection.
Acute myeloid leukaemia (AML) is an uncontrolled clonal proliferation of abnormal myeloid progenitor cells in the bone marrow and blood. Advances in cancer genomics have revealed the spectrum of ...somatic mutations that give rise to human AML and drawn our attention to its molecular evolution and clonal architecture. It is now evident that most AML genomes harbour small numbers of mutations, which are acquired in a stepwise manner. This characteristic, combined with our ability to identify mutations in individual leukaemic cells and our detailed understanding of normal human and murine haematopoiesis, makes AML an excellent model for understanding the principles of cancer evolution. Furthermore, a better understanding of how AML evolves can help us devise strategies to improve the therapy and prognosis of AML patients. Here, we draw from recent advances in genomics, clinical studies and experimental models to describe the current knowledge of the clonal evolution of AML and its implications for the biology and treatment of leukaemias and other cancers.
N
-methyladenosine (m
A) is an abundant internal RNA modification
that is catalysed predominantly by the METTL3-METTL14 methyltransferase complex
. The m
A methyltransferase METTL3 has been linked to ...the initiation and maintenance of acute myeloid leukaemia (AML), but the potential of therapeutic applications targeting this enzyme remains unknown
. Here we present the identification and characterization of STM2457, a highly potent and selective first-in-class catalytic inhibitor of METTL3, and a crystal structure of STM2457 in complex with METTL3-METTL14. Treatment of tumours with STM2457 leads to reduced AML growth and an increase in differentiation and apoptosis. These cellular effects are accompanied by selective reduction of m
A levels on known leukaemogenic mRNAs and a decrease in their expression consistent with a translational defect. We demonstrate that pharmacological inhibition of METTL3 in vivo leads to impaired engraftment and prolonged survival in various mouse models of AML, specifically targeting key stem cell subpopulations of AML. Collectively, these results reveal the inhibition of METTL3 as a potential therapeutic strategy against AML, and provide proof of concept that the targeting of RNA-modifying enzymes represents a promising avenue for anticancer therapy.
Effect of Mutation Order on Myeloproliferative Neoplasms Ortmann, Christina A; Kent, David G; Nangalia, Jyoti ...
New England journal of medicine/The New England journal of medicine,
02/2015, Letnik:
372, Številka:
7
Journal Article
Recenzirano
Odprti dostop
About 10% of myeloproliferative neoplasms carry mutations in both
TET2
and
JAK2
. Clinical presentation, risk of thrombosis, and rates of tumor progression are affected by which gene mutation is ...acquired first.
Cancers evolve as a consequence of the stepwise accumulation of somatic lesions, with competition between subclones and sequential subclonal evolution.
1
,
2
Darwinian selection of variant subclones results in acquisition of biologic attributes required for tumor formation.
3
Genetic interaction is central to this process, but it is unclear how mutated genes interact to generate the phenotypic hallmarks of cancer, and the influence, if any, of the order in which mutations are acquired is unknown.
4
Cooperation between different genetic lesions has been observed in cell-line models of transformation
5
and in mouse models of several cancers.
6
,
7
Moreover, the consequences of an early . . .
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