Novel Treatment Strategies Utilizing Immune Reactions against Chronic Myelogenous Leukemia Stem Cells.
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ABSTRACT:
SUBMITTER: Matsushita M
PROVIDER: S-EPMC8582551 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Imatinib-insensitive leukemia stem cells (LSCs) are believed to be responsible for resistance to BCR-ABL tyrosine kinase inhibitors and relapse of chronic myelogenous leukemia (CML). Identifying therapeutic targets to eradicate CML LSCs may be a strategy to cure CML. In the present study, we discovered a positive feedback loop between BCR-ABL and protein arginine methyltransferase 5 (PRMT5) in CML cells. Overexpression of PRMT5 was observed in human CML LSCs. Silencing PRMT5 with shRNA or blocking PRMT5 methyltransferase activity with the small-molecule inhibitor PJ-68 reduced survival, serial replating capacity, and long-term culture-initiating cells (LTC-ICs) in LSCs from CML patients. Further, PRMT5 knockdown or PJ-68 treatment dramatically prolonged survival in a murine model of retroviral BCR-ABL-driven CML and impaired the in vivo self-renewal capacity of transplanted CML LSCs. PJ-68 also inhibited long-term engraftment of human CML CD34+ cells in immunodeficient mice. Moreover, inhibition of PRMT5 abrogated the Wnt/?-catenin pathway in CML CD34+ cells by depleting dishevelled homolog 3 (DVL3). This study suggests that epigenetic methylation modification on histone protein arginine residues is a regulatory mechanism to control self-renewal of LSCs and indicates that PRMT5 may represent a potential therapeutic target against LSCs.
| S-EPMC5096815 | biostudies-other
Project description:Chronic myelogenous leukemia (CML) results from transformation of a long-term hematopoietic stem cell (LTHSC) by expression of the BCR-ABL fusion gene. However, BCR-ABL-expressing LTHSCs are heterogeneous in their capacity as leukemic stem cells (LSCs). Although discrepancies in proliferative, self-renewal, and differentiation properties of normal LTHSCs are being increasingly recognized, the mechanisms underlying heterogeneity of leukemic LTHSCs are poorly understood. Using a CML mouse model, we identified gene expression differences between leukemic and nonleukemic LTHSCs. Expression of the thrombopoietin (THPO) receptor MPL was elevated in leukemic LTHSC populations. Compared with LTHSCs with low MPL expression, LTHSCs with high MPL expression showed enhanced JAK/STAT signaling and proliferation in response to THPO in vitro and increased leukemogenic capacity in vivo. Although both G0 and S phase subpopulations were increased in LTHSCs with high MPL expression, LSC capacity was restricted to quiescent cells. Inhibition of MPL expression in CML LTHSCs reduced THPO-induced JAK/STAT signaling and leukemogenic potential. These same phenotypes were also present in LTHSCs from patients with CML, and patient LTHSCs with high MPL expression had reduced sensitivity to BCR-ABL tyrosine kinase inhibitor treatment but increased sensitivity to JAK inhibitors. Together, our studies identify MPL expression levels as a key determinant of heterogeneous leukemia-initiating capacity and drug sensitivity of CML LTHSCs and suggest that high MPL-expressing CML stem cells are potential targets for therapy.
| S-EPMC4767357 | biostudies-literature
Project description:We show the molecular and functional characterization of a novel population of lineage-negative CD34-negative (Lin- CD34-) hematopoietic stem cells (HSCs) from chronic myelogenous leukemia (CML) patients at diagnosis. Molecular caryotyping and quantitative analysis of BCR/ABL transcript demonstrated that about one third of CD34- was leukemic. CML CD34- cells showed kinetic quiescence and limited clonogenic capacity. However, stroma-dependent cultures and cytokines induced CD34 expression on some HSCs, cell cycling, acquisition of clonogenic activity and increased expression of BCR/ABL transcript. CML CD34- cells showed an engraftment rate in immunodeficient mice similar to that of CD34+ cells. Gene expression profiling revealed the down-regulation of cell cycle arrest genes together with genes involved in antigen presentation and processing, while the expression of angiogenic factors was strongly up-regulated when compared to normal counterparts. Flow cytometry analysis confirmed the significant down-regulation of HLA class I and II molecules in CML CD34-cells. Increasing doses of imatinib mesilate (IM) did not affect fusion transcript levels, BCR-ABL kinase activity and the clonogenic efficiency of CML CD34- cells as compared to leukemic CD34+cells. Thus, we identified in CML a novel CD34- leukemic stem cell subset with peculiar molecular and functional characteristics which may be a potential target for CML therapeutics.
2010-01-05 | GSE11675 | GEO
Project description:We show the molecular and functional characterization of a novel population of lineage-negative CD34-negative (Lin- CD34-) hematopoietic stem cells (HSCs) from chronic myelogenous leukemia (CML) patients at diagnosis. Molecular caryotyping and quantitative analysis of BCR/ABL transcript demonstrated that about one third of CD34- was leukemic. CML CD34- cells showed kinetic quiescence and limited clonogenic capacity. However, stroma-dependent cultures and cytokines induced CD34 expression on some HSCs, cell cycling, acquisition of clonogenic activity and increased expression of BCR/ABL transcript. CML CD34- cells showed an engraftment rate in immunodeficient mice similar to that of CD34+ cells. Gene expression profiling revealed the down-regulation of cell cycle arrest genes together with genes involved in antigen presentation and processing, while the expression of angiogenic factors was strongly up-regulated when compared to normal counterparts. Flow cytometry analysis confirmed the significant down-regulation of HLA class I and II molecules in CML CD34-cells. Increasing doses of imatinib mesilate (IM) did not affect fusion transcript levels, BCR-ABL kinase activity and the clonogenic efficiency of CML CD34- cells as compared to leukemic CD34+cells. Thus, we identified in CML a novel CD34- leukemic stem cell subset with peculiar molecular and functional characteristics which may be a potential target for CML therapeutics. Leukemic cells were obtained from 12 chronic phase Ph+ CML patients at diagnosis and before treatment. Normal samples were leukapheresis products from 12 healthy stem cell donors receiving recombinant human granulocyte colony-stimulating factor (G-CSF; Lenograstim, Sanofi-Aventis, Milan, Italy). The protocol was approved by the ethical committee of the University Hospital and each patient/donor gave written informed consent. Hemopoietic stem/progenitor cell purification and phenotypic analyses were performed as previously described (Lemoli et al, Br J Haematol, 2003; Lemoli RM et al., Blood, 1997). Aliquots of sorted Lin-CD34-, Lin-CD34+ and Lin+CD34+ were reanalyzed by FacScan (Becton Dickinson, Franklin Lakes, NJ) to assess their purities. Total cellular RNA was extracted from 0.5x105 cells of each sample using RNeasy Micro kit (Qiagen, Valencia, CA) following the protocol supplied by the manufacturer. Disposable RNA chips (Agilent RNA 6000 Nano LabChip kit, Agilent Technologies, Waldbrunn, Germany) were used to determine the concentration and purity/integrity of RNA samples using Agilent 2100 Bioanalyzer. RNAs originating from 12 normal donors or from 12 CML patients were pooled in order to obtain at least 2 mg per sample. One-cycle target labeling assays, as well as the Affymetrix Human HG-U95Av2 GeneChip arrays hybridization, staining, and scanning, were performed, using Affymetrix standard protocols (Affymetrix, Santa Clara,CA).
2010-01-04 | E-GEOD-11675 | biostudies-arrayexpress
Project description:Leukemic cells disrupt normal patterns of blood cell formation, but little is understood about the mechanism. We investigated whether leukemic cells alter functions of normal hematopoietic stem and progenitor cells. Exposure to chronic myelogenous leukemia (CML) caused normal mouse hematopoietic progenitor cells to divide more readily, altered their differentiation, and reduced their reconstitution and self-renewal potential. Interestingly, the normal bystander cells acquired gene expression patterns resembling their malignant counterparts. Therefore, much of the leukemia signature is mediated by extrinsic factors. Indeed, IL-6 was responsible for most of these changes. Compatible results were obtained when human CML were cultured with normal human hematopoietic progenitor cells. Furthermore, neutralization of IL-6 prevented these changes and treated the disease.
| S-EPMC4447336 | biostudies-literature
Project description:BackgroundChronic myelogenous leukemia (CML) is a myeloproliferative neoplasm that arises from the acquisition of constitutively active BCR-ABL tyrosine kinase in hematopoietic stem cells. The persistence of bone marrow leukemia stem cells (LSCs) is the main cause of TKI resistance and CML relapse. Therefore, finding a key target or pathway to selectively target LSCs is of great significance for the thorough treatment of CML.MethodsIn this study, we aimed to identify key microRNAs, microRNA targets and pathways for the treatment of CML LSCs by integrating analyses of three microarray data profiles. We identified 51 differentially expressed microRNAs through integrated analysis of GSE90773 and performed functional gene predictions for microRNAs. Then, GSE11889 and GSE11675 were integrated to obtain differentially expressed genes (DEGs), and the overlapping DEGs were used as models to identify predictive functional genes. Finally, we identified 116 predictive functional genes. Clustering and significant enrichment analysis of 116 genes was based on function and signaling pathways. Subsequently, a protein interaction network was constructed, and module analysis and topology analysis were performed on the network.ResultsA total of 11 key candidate targets and 33 corresponding microRNAs were identified. The key pathways were mainly concentrated on the PI3K/AKT, Ras, JAK/STAT, FoxO and Notch signaling pathways. We also found that LSCs negatively regulated endogenous and exogenous apoptotic pathways to escape from apoptosis.ConclusionWe identified key candidate targets and pathways for CML LSCs through bioinformatics methods, which improves our understanding of the molecular mechanisms of CML LSCs. These candidate genes and pathways may be therapeutic targets for CML LSCs.
| S-EPMC6732304 | biostudies-literature
Project description:Imatinib is considered standard therapy for patients with chronic myelogenous leukemia (CML), inducing a high rate of hematologic and cytogenetic responses. Despite these excellent results, several patients develop resistance to imatinib. Mechanisms of resistance are varied and include BCR-ABL1 kinase domain mutations, decreased entry of imatinib into cells, acquisition of secondary genetic changes and activation of alternate signaling pathways. Second-generation tyrosine kinase inhibitors (TKI) (dasatinib, nilotinib) were developed as an alternative for patients that develop resistance or are intolerant to imatinib. Dasatinib is a dual Abl/Src kinase TKI that is structurally unrelated to imatinib and is approved for therapy of all phases of CML in patients who are resistant or intolerant to imatinib. Nilotinib is a compound related to imatinib that has greater specificity and improved binding characteristics, and has clinical activity in the setting of imatinib failure. Resistance to multiple TKIs does occur, particularly in patients with the T315I mutation. Several new agents are in development including new TKIs, aurora kinase inhibitors and homoharringtonine.
| S-EPMC4109296 | biostudies-literature
Project description:Chronic myelogenous leukemia (CML) caused by hematopoietic stem cells expressing the Bcr-Abl fusion gene may be controlled by Bcr-Abl tyrosine kinase inhibitors (TKIs). However, CML-initiating cells are resistant to TKIs and may persist as minimal residual disease. We demonstrate that mice deficient in Sipa1, which encodes Rap1 GTPase-activating protein, rarely develop CML upon transfer of primary hematopoietic progenitor cells (HPCs) expressing Bcr-Abl, which cause lethal CML disease in wild-type mice. Resistance requires both T cells and nonhematopoietic cells. Sipa1-/- mesenchymal stroma cells (MSCs) show enhanced activation and directed migration to Bcr-Abl+ cells in tumor tissue and preferentially produce Cxcl9, which in turn recruits Sipa1-/- memory T cells that have markedly augmented chemotactic activity. Thus, Sipa1 deficiency uncovers a host immune mechanism potentially capable of eradicating Bcr-Abl+ HPCs via coordinated interplay between MSCs and immune T cells, which may provide a clue for radical control of human CML.
| S-EPMC5834470 | biostudies-literature
Project description:We characterized leukemia stem cells (LSC) in chronic phase chronic myelogenous leukemia (CML) using a transgenic mouse model. LSC were restricted to cells with long-term hematopoietic stem cell (LTHSC) phenotype. CML LTHSC demonstrated reduced homing and retention in the bone marrow (BM), related to decreased CXCL12 expression in CML BM, resulting from increased G-CSF production by leukemia cells. Altered cytokine expression in CML BM was associated with selective impairment of normal LTHSC growth and a growth advantage to CML LTHSC. Imatinib (IM) treatment partially corrected abnormalities in cytokine levels and LTHSC growth. These results were validated using human CML samples and provide improved understanding of microenvironmental regulation of normal and leukemic LTHSC and their response to IM in CML.
| S-EPMC3332001 | biostudies-literature
Project description:Our study investigates the features and anti-tumor function of extracellular vesicles (EVs) isolated from our well described NK cell line - NK3.3 - the only published clonal, normal human cell line to date. Natural killer (NK) cells, critical for proper immune function, destroy tumor cells primarily through the release of granules containing potent cytolytic molecules. NK cells also release these molecules within membrane-bound exosomes and microvesicles collectively known as EVs. We show that NK3.3 EVs contain the cytolytic molecules perforin, granzymes A and B, and granulysin, and an array of common EV proteins. We previously showed that the E3 ubiquitin ligase identified by our laboratory, natural killer lytic-associated molecule (NKLAM/RNF19b), is localized to NK granules and is essential for maximal NK killing; our current study shows NKLAM situated within the NK3.3 EV membrane. We demonstrate that treatment of an array of hematopoietic and non-hematopoietic tumor cell lines with NK3.3 EVs inhibits proliferation and induces apoptosis and cell death while leaving normal cells unaffected. The anti-tumor effects of NK3.3EVs were evaluated via proteomic analysis of K562 leukemia cells treated with NK3.3-derived EVs compared to treatment with non-cytotoxic HEK293 cell-derived EVs or PBS. The results of this analysis suggest strong inhibitory regulation of cell cycle- and cell survival-associated proteins. Taken together, our study suggests that NK3.3 EVs have the potential to be effective immunotherapeutic agents.
2021-09-07 | PXD027221 | Pride