scholarly journals Self-Renewal Pathways in Acute Myeloid Leukemia Stem Cells

2020 ◽  
Author(s):  
Jonason Yang ◽  
Nunki Hassan ◽  
Sheng Xiang Franklin Chen ◽  
Jayvee Datuin ◽  
Jenny Y. Wang

Acute myeloid leukemia (AML) is a difficult-to-treat blood cancer. A major challenge in treating patients with AML is relapse, which is caused by the persistence of leukemia stem cells (LSCs). Self-renewal is a defining property of LSCs and its deregulation is crucial for re-initiating a new leukemia after chemotherapy. Emerging therapeutic agents inhibiting aberrant self-renewal pathways, such as anti-RSPO3 monoclonal antibody discovered in our recent study, present significant clinical potential that may extend beyond the scope of leukemogenesis. In this chapter, we provide an overview of normal and malignant hematopoietic stem cells, discuss current treatments and limitations, and review key self-renewal pathways and potential therapeutic opportunities in AML.

Author(s):  
Peipei Wang ◽  
Mengdie Feng ◽  
Guoqiang Han ◽  
Rong Yin ◽  
Yashu Li ◽  
...  

N6-methyladenosine (m6A) is a commonly modification of mammalian mRNAs and plays key roles in various cellular processes. Emerging evidence reveals the importance of RNA m6A modification in maintaining stem cell function in normal hematopoiesis and leukemogenesis. In this review, we first briefly summarize the latest advances in RNA m6A biology, and further highlight the roles of m6A writers, readers and erasers in normal hematopoiesis and acute myeloid leukemia. Moreover, we also discuss the mechanisms of these m6A modifiers in preserving the function of hematopoietic stem cells (HSCs) and leukemia stem cells (LSCs), as well as potential strategies for targeting m6A modification related pathways. Overall, we provide a comprehensive summary and our insights into the field of RNA m6A in normal hematopoiesis and leukemia pathogenesis.


Blood ◽  
1995 ◽  
Vol 86 (8) ◽  
pp. 2906-2912 ◽  
Author(s):  
D Haase ◽  
M Feuring-Buske ◽  
S Konemann ◽  
C Fonatsch ◽  
C Troff ◽  
...  

Acute myeloid leukemia (AML) is a heterogenous disease according to morphology, immunophenotype, and genetics. The retained capacity of differentiation is the basis for the phenotypic classification of the bulk population of leukemic blasts and the identification of distinct subpopulations. Within the hierarchy of hematopoietic development and differentiation it is still unknown at which stage the malignant transformation occurs. It was our aim to analyze the potential involvement of cells with the immunophenotype of pluripotent stem cells in the leukemic process by the use of cytogenetic and cell sorting techniques. Cytogenetic analyses of bone marrow aspirates were performed in 13 patients with AML (11 de novo and 2 secondary) and showed karyotype abnormalities in 10 cases [2q+, +4, 6p, t(6:9), 7, +8 in 1 patient each and inv(16) in 4 patients each]. Aliquots of the samples were fractionated by fluorescence-activated cell sorting of CD34+ cells. Two subpopulations, CD34+/CD38-(early hematopoietic stem cells) and CD34+/CD38+ (more mature progenitor cells), were screened for karyotype aberations as a marker for leukemic cells. Clonal abnormalities and evaluable metaphases were found in 8 highly purified CD34+/CD38-populations and in 9 of the CD34+/CD38-specimens, respectively. In the majority of cases (CD34+/CD38-, 6 of 8 informative samples; CD34+/CD38+, 5 of 9 informative samples), the highly purified CD34+ specimens also contained cytogenetically normal cells. Secondary, progression-associated chromosomal changes (+8, 12) were identified in the CD34+/CD38-cells of 2 patients. We conclude that clonal karyotypic abnormalities are frequently found in the stem cell-like (CD34+/CD38-) and more mature (CD34+/CD38+) populations of patients with AML, irrespective of the phenotype of the bulk population of leukemic blasts and of the primary or secondary character of the leukemia. Our data suggest that, in AML, malignant transformation as well as disease progression may occur at the level of CD34+/CD38-cells with multilineage potential.


2010 ◽  
Vol 207 (3) ◽  
pp. 475-489 ◽  
Author(s):  
Yoon-Chi Han ◽  
Christopher Y. Park ◽  
Govind Bhagat ◽  
Jinping Zhang ◽  
Yulei Wang ◽  
...  

The function of microRNAs (miRNAs) in hematopoietic stem cells (HSCs), committed progenitors, and leukemia stem cells (LSCs) is poorly understood. We show that miR-29a is highly expressed in HSC and down-regulated in hematopoietic progenitors. Ectopic expression of miR-29a in mouse HSC/progenitors results in acquisition of self-renewal capacity by myeloid progenitors, biased myeloid differentiation, and the development of a myeloproliferative disorder that progresses to acute myeloid leukemia (AML). miR-29a promotes progenitor proliferation by expediting G1 to S/G2 cell cycle transitions. miR-29a is overexpressed in human AML and, like human LSC, miR-29a-expressing myeloid progenitors serially transplant AML. Our data indicate that miR-29a regulates early hematopoiesis and suggest that miR-29a initiates AML by converting myeloid progenitors into self-renewing LSC.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 683-683
Author(s):  
Christopher Y. Park ◽  
Yoon-Chi Han ◽  
Govind Bhagat ◽  
Jian-Bing Fan ◽  
Irving L Weissman ◽  
...  

Abstract microRNAs (miRNAs) are short, non-protein encoding RNAs that bind to the 3′UTR’s of target mRNAs and negatively regulate gene expression by facilitating mRNA degradation or translational inhibition. Aberrant miRNA expression is well-documented in both solid and hematopoietic malignancies, and a number of recent miRNA profiling studies have identified miRNAs associated with specific human acute myeloid leukemia (AML) cytogenetic groups as well as miRNAs that may prognosticate clinical outcomes in AML patients. Unfortunately, these studies do not directly address the functional role of miRNAs in AML. In fact, there is no direct functional evidence that miRNAs are required for AML development or maintenance. Herein, we report on our recent efforts to elucidate the role of miRNAs in AML stem cells. miRNA expression profiling of AML stem cells and their normal counterparts, hematopoietic stem cells (HSC) and committed progenitors, reveals that miR-29a is highly expressed in human hematopoietic stem cells (HSC) and human AML relative to normal committed progenitors. Ectopic expression of miR-29a in mouse HSC/progenitors is sufficient to induce a myeloproliferative disorder (MPD) that progresses to AML. During the MPD phase of the disease, miR-29a alters the composition of committed myeloid progenitors, significantly expedites cell cycle progression, and promotes proliferation of hematopoietic progenitors at the level of the multipotent progenitor (MPP). These changes are manifested pathologically by marked granulocytic and megakaryocytic hyperplasia with hepatosplenomegaly. Mice with miR-29a-induced MPD uniformly progress to an AML that contains a leukemia stem cell (LSC) population that can serially transplant disease with as few as 20 purified LSC. Gene expression analysis reveals multiple tumor suppressors and cell cycle regulators downregulated in miR-29a expressing cells compared to wild type. We have demonstrated that one of these genes, Hbp1, is a bona fide miR-29a target, but knockdown of Hbp1 in vivo does not recapitulate the miR-29a phenotype. These data indicate that additional genes are required for miR-29a’s leukemogenic activity. In summary, our data demonstrate that miR-29a regulates early events in normal hematopoiesis and promotes myeloid differentiation and expansion. Moreover, they establish that misexpression of a single miRNA is sufficient to drive leukemogenesis, suggesting that therapeutic targeting of miRNAs may be an effective means of treating myeloid leukemias.


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