Project description:Little is known about the impact of DNA methylation on the evolution/progression of chronic myeloid leukemia (CML). We investigated the methylome of CML patients in chronic phase (CP-CML), accelerated phase (AP-CML) and blast crisis (BC-CML) as well as in controls by reduced representation bisulfite sequencing. While only ~600 differentially methylated CpG sites were identified in samples obtained from CP-CML patients compared to controls, ~6,500 differentially methylated CpG sites were found in cells from BC-CML patients. In the majority of affected CpG sites methylation was increased. In CP-CML patients who progressed to AP-CML/BC-CML, we identified up to 897 genes which were methylated at the time of progression but not at the time of diagnosis. Using RNA-sequencing, we observed downregulated expression of many of these genes in BC-CML compared to CP-CML-derived cells. Several of them are well-known tumor suppressor genes or regulators of cell proliferation. 5-aza-2 -deoxycytidine treatment of CML cells resulted in gene re-expression and in a dose-dependent cell growth reduction. Single nucleotide variants of certain epigenetic modifiers during CML progression were not found. Together, our results demonstrate that methylation changes occur frequently during CML progression and may provide a useful basis for revealing new targets of therapy in advanced CML.
Project description:In our previous study, the roles of zinc finger protein X-linked (ZFX) in CML cells were revealed. We showed that ZFX expression was significantly higher in CML CD34+ cells than in control cells. Overexpression and gene silencing experiments indicated that ZFX promoted the in vitro growth of CML cells, conferred imatinib mesylate (IM) resistance to these cells, and enhanced BCR/ABL-induced malignant transformation. To obtain molecular insights of how ZFX modulates the growth and imatinib response of CML stem and progenitor cells, we generated microarray data comparing ZFX silenced CML CD34+ cells with control (Scramble) cells.
Project description:The circRNAs of chronic myelelogenous leukemia (CML) accelerated phase and chronic phase (CP) were more obvious than normal subjects. QRT-PCR verified that the expressions of hsa_circ_0001523, hsa_circ_0006010 and hsa_circ_0066971 were significantly up-regulated, while the expressions of hsa_circ_000095, hsa_circ_0001801 and HSA_circ_0002903 were down-regulated in advanced patients. Bioinformatics analysis revealed that some dysregulated crRnas may be active in important biological pathways by acting as miRNA sponges during CML disease progression. These six circrnas have high diagnostic value. Our study confirms significant circrNA dysregulation in CML patients and describes a circrNA marker associated with CML disease progression.
Project description:This study compares the epigenetic signatures of CD34+ cells from chronic phase chronic myeloid leukemia (CML) samples and blast phase CML samples v.s. normal CD34+ cells from cord blood and adult bone marrow samples. H3K27me3 genomic loci were detected by ChIP-seq.
Project description:Background MicroRNAs are important regulators of transcription in hematopoiesis. Their expression deregulations were described in association with pathogenesis of some hematological malignancies. This study provides integrated microRNA expression profiling at different phases of chronic myeloid leukemia (CML) with the aim to select CML specific miRNAs and find new possible biomarkers. The functions of in silico filtered targets are in this report annotated and discussed in relation to CML pathogenesis. Results Using microarrays we identified differential expression profiles of 49 miRNAs in CML patients at diagnosis, in hematological relapse, therapy failure, blast crisis and major molecular response. The expression deregulation of miR-150, miR-20a, miR-17, miR-19a, miR-103, miR-144, miR-155, miR-181a, miR-221 and miR-222 in CML was confirmed by real-time quantitative PCR and in silico analyses identified targeted genes of these miRNAs encoding proteins that are involved in cell cycle, growth inhibition, MAPK, ErBb, transforming growth factor beta and p53 signaling pathways that are related to CML. Validated miR-150 decreased levels were detected in patients at diagnosis, in blast crisis and 67% of hematological relapses and showed significant negative correlation with miR-150 proved target MYB and with BCR-ABL transcript level. Conclusions This study revealed microRNAs that may be related to the CML pathogenesis and may reflect transformation from chronic to accelerated phases. The obtained expression patterns in peripheral blood total leukocytes during the course of CML suggest specific miRNAs as possible biomarkers. The annotated functions of in silico filtered targets of selected miRNAs outline mechanisms whereby microRNAs may be involved in CML pathogenesis.
Project description:Leukemic stem cells (LSCs) can acquire non-mutational resistance following drug treatment leading to therapeutic failure and relapse. However, oncogene-independent mechanisms of drug persistence in LSCs are incompletely understood, which is the primary focus of this study. We integrated proteomics, transcriptomics, and metabolomics to determine the contribution of STAT3 in promoting metabolic changes in tyrosine kinase inhibitor (TKI) persistent chronic myeloid leukemia (CML) cells. Proteomic and transcriptional differences in TKI persistent CML cells revealed BCR-ABL-independent STAT3 activation in these cells. While knockout of STAT3 inhibited the CML cells from developing drug-persistence, inhibition of STAT3 using a small molecule inhibitor sensitized the persistent CML cells to TKI treatment. Interestingly, given the role of phosphorylated STAT3 as a transcription factor, it localized uniquely to genes regulating metabolic pathways in the TKI-persistent CML stem and progenitor cells. Subsequently, we observed that STAT3 dysregulated mitochondrial metabolism forcing the TKI-persistent CML cells to depend on glycolysis, unlike TKI-sensitive CML cells, which are more reliant on oxidative phosphorylation. Finally, targeting pyruvate kinase M2, a rate-limiting glycolytic enzyme, specifically eradicated the TKI-persistent CML cells. By exploring the role of STAT3 in altering metabolism, we provide critical insight into identifying potential therapeutic targets for eliminating TKI-persistent LSCs.
Project description:We identified the BCL6 protooncogene as a critical downstream effector of FoxO3A in self-renewal signaling of CML-initiating cells. BCL6 represses Arf and p53 in CML cells and is required for leukemia stem cell maintenance, colony formation and initiation of leukemia in transplant recipients. Importantly, peptide inhibition of BCL6 in human CML cells compromises colony formation and leukemia-initiation in xenotransplanted mouse recipients. These findings identify peptide-inhibition of BCL6 as a novel strategy to eradicate leukemia-initiating cells in CML. Identification of BCL6 binding sites in human CML cell line JURL-MK1
Project description:Properties of cancer stem cells (CSC) involved in drug-resistance and relapse have significant effect on clinical outcome. Although tyrosine kinase inhibitors (TKIs) have dramatically improved survival of patients with chronic myelogenous leukemia (CML), TKIs have not fully cure CML due to TKI-resistant CML stem cells. Moreover, the relapse after discontinuation of TKIs has not been predicted in CML patients with best TKI-response. In our study, pre-hematoopoietic progenitor cells (pre-HPCs), a model of CML stem cells derived from CML-iPSCs identified a novel antigen of TKI-resistant CML cells. Even in the fraction reported as TKI-sensitive, the antigen+ cells showed TKI-resistance in CML patients. In addition, residual CML cells in patients with optimal TKI-response were concentrated in the antigen+ population.
Project description:We used massively parallel DNA sequencing of paired-end ditags (DNA-PET) to identify structural genetic factors associated with disease progression and drug-resistance in representative samples from four CML patients and one CML cell line. The functional consequences of our genetic findings were evaluated in primary CML cells and cell lines, and validated in a larger CML cohort. We discovered a novel intronic deletion that correlated with imatinib-resistance, and was subsequently confirmed to be a polymorphism in normal East-Asian, but not African or Caucasian, populations. We found that the polymorphism favored expression of transcripts lacking a pro-apoptotic domain, which is critical for imatinib-induced cell death. A CML cell line containing the polymorphism also exhibited BCR-ABL-independent imatinib-resistance. Structural variations of 5 human CML samples were identified by long span paired-end sequencing
Project description:Even in the era of ABL tyrosine kinase inhibitors, eradication of chronic myeloid leukemia (CML) stem cells still remains to be a prerequisite for the complete cure of the disease. Interferon-α (IFNα), which has been used long for the treatment for CML-chronic phase, are now being re-evaluated. However, the molecular mechanism involved in the action of IFNα on CML stem cells have not been elucidated yet. In this study we have found that IFNα upregulates CCAAT/Enhancer Binding Protein β (C/EBPβ), a transcription factor required for demand-driven granulopoiesis, through activation of STAT1 and STAT5 in BCR-ABL-expressing cells. Activated STAT1 and STAT5 were recruited to the newly identified 3’ distal enhancer region of Cebpb, which contains tandemly aligned interferon-g activated sequences (GAS). Genome editing-mediated repression or deletion of the GAS elements significantly abrogated the IFNα-dependent upregulation of C/EBPβ. IFNα induces differentiation and exhaustion of CML stem cells both in vitro and in vivo in a C/EBPβ-dependent manner. In addition, IFNα upregulates C/EBPβ and induces exhaustion of CD34+ CML stem cells obtained from CML patients. Collectively, these data clearly show that C/EBPβ is a critical factor in IFNα signaling that induces differentiation and exhaustion of CML stem cells.