Epigenetic mechanisms contribute to deregulated gene expression of hematopoietic progenitors in Myelodysplastic Syndromes (MDS). Hypomethylating agents are able to improve peripheral cytopenias in MDS patients. To identify critical gene expression changes induced by hypomethylating agents, we analyzed gene expression profiling (GEP) of myelodysplastic and normal CD34+ hematopoietic stem cells treated in vitro with or without decitabine. Four MDS and two untreated early stage Hodgkins lymphomas were analyzed for GEP. Mock treated CD34+ stem cells segregate according to diagnosis and karyotype. After decitabine treatment, gene expression changes were more consistent on MDS CD34+ cells with abnormal kayotype. Comparing decitabine-induced genes with those found down-regulated in mock-treated MDS cells, we identified a list of candidate tumor suppressor genes in MDS. By real-time RT-PCR we confirmed expression changes for three selected genes CD9, CXCR4 and GATA2 in 12 MDS patients and 4 controls. CD9 was widely repressed in most MDS CD34+ cell samples, although similar levels of methylation were found in both normal and MDS total bone marrows. CXCR4 promoter methylation was absent in total bone marrows from 36 MDS patients. In conclusion, changes in gene expression changes induced by hypomethylating treatment are more pronounced in CD34+ cells from abnormal karyotype.
Gene expression profiling of myelodysplastic CD34+ hematopoietic stem cells treated in vitro with decitabine.
Sex, Age, Specimen part, Disease
View SamplesIt has long been known that leukemic cells disrupt normal patterns of blood cell formation, but little is understood about mechanisms. It has generally been assumed that normal hematopoietic stem and progenitor cells (HSPC) are simply out-competed for space by malignant cells. We designed a strategy to determine if leukemic cells alter intrinsic properties and functions of normal HSPCs. Chimeric mice were generated by transplantation of normal marrow and marrow from an inducible transgenic model of chronic myelogenous leukemia (CML). With induction of CML, the composition of the marrow changed dramatically, and normal HSPCs divided more readily and lost their ability to produce lymphocytes. In contrast, only modest changes were recorded in numbers of normal hematopoietic stem cells (HSCs). However, these stem cells were not unscathed, and had reduced reconstitution and self-renewal potential upon transplantation. Interestingly, the normal bystander cells acquired gene expression patterns resembling their neighboring malignant counterparts. This suggested that much of the leukemia signature is mediated by extrinsic factors in the environment.
Treatment of chronic myelogenous leukemia by blocking cytokine alterations found in normal stem and progenitor cells.
Specimen part
View SamplesThe estrogen-dependence of breast cancer has long been recognized, however, the role of 17-estradiol (E2) in cancer initiation was not known until we demonstrated that it induces complete neoplastic transformation of the human breast epithelial cells MCF-10F. E2-treatment of MCF-10F cells progressively induced high colony efficiency and loss of ductulogenesis in early transformed (trMCF) cells and invasiveness in Matrigel invasion chambers. The cells that
Epithelial to mesenchymal transition in human breast epithelial cells transformed by 17beta-estradiol.
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View SamplesPTEN loss or PI3K/AKT signaling pathway activation correlates with human prostate cancer progression and metastasis. However, in preclinical murine models, deletion of Pten alone fails to mimic the significant metastatic burden that frequently accompanies the end stage of human disease. To identify additional pathway alterations that cooperate with PTEN loss in prostate cancer progression, we surveyed human prostate cancer tissue microarrays and found that the RAS/MAPK pathway is significantly elevated both in primary and metastatic lesions. In an attempt to model this event, we crossed conditional activatable K-rasG12D/WT mice with the prostate conditional Pten deletion model we previously generated. Although RAS activation alone cannot initiate prostate cancer development, it significantly accelerated progression caused by PTEN loss, accompanied by epithelial-to-mesenchymal transition (EMT) and macrometastasis with 100% penitence. A novel stem/progenitor subpopulation with mesenchymal characteristics was isolated from the compound mutant prostates, which was highly metastatic upon orthotopic transplantation. Importantly, inhibition of RAS/MAPK signaling by PD325901, a MEK inhibitor, significantly reduced the metastatic progression initiated from transplanted stem/progenitor cells. Collectively, these data indicate that activation of RAS/MAPK signaling serves as a potentiating second hit to alteration of the PTEN/PI3K/AKT axis and co-targeting both pathways is highly effective in preventing the development of metastatic prostate cancers.
Pten loss and RAS/MAPK activation cooperate to promote EMT and metastasis initiated from prostate cancer stem/progenitor cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A novel crosstalk between CCAR2 and AKT pathway in the regulation of cancer cell proliferation.
Cell line
View SamplesCCAR2 is a nuclear protein recently emerged as a pivotal player of the DNA damage response since it has been found involved in both apoptosis induction and DNA repair. Differently, its role in tumorigenesis and cancer progression is still elusive. In our studies we found that CCAR2 depletion impairs the proliferation of human cancer cell lines, but leaves unaffected the growth of normal immortalized cells. To better investigate this point we performed a genome wide gene expression analyses in U2OS and BJ-hTERT depleted of CCAR2 and we found that loss of this protein causes the deregulation of genes implicated in the AKT pathway specifically in U2OS cells, but not in BJ-hTERT. In accordance with these results we found a reduction in AKT activation in all the tested cancer cell lines depleted of CCAR2, but not in the normal ones. The defective activation of AKT is caused by the upregulation of TRB3 gene in cancer cells depleted of CCAR2 and finally results in the reduction of GSK3 phosphorylation, prevention of G1/S transition and inhibition of cancer cell growth.
A novel crosstalk between CCAR2 and AKT pathway in the regulation of cancer cell proliferation.
Cell line
View SamplesCCAR2 is a nuclear protein recently emerged as a pivotal player of the DNA damage response since it has been found involved in both apoptosis induction and DNA repair. Differently, its role in tumorigenesis and cancer progression is still elusive. In our studies we found that CCAR2 depletion impairs the proliferation of human cancer cell lines, but leaves unaffected the growth of normal immortalized cells. To better investigate this point we performed a genome wide gene expression analyses in U2OS and BJ-hTERT depleted of CCAR2 and we found that loss of this protein causes the deregulation of genes implicated in the AKT pathway specifically in U2OS cells, but not in BJ-hTERT. In accordance with these results we found a reduction in AKT activation in all the tested cancer cell lines depleted of CCAR2, but not in the normal ones. The defective activation of AKT is caused by the upregulation of TRB3 gene in cancer cells depleted of CCAR2 and finally results in the reduction of GSK3 phosphorylation, prevention of G1/S transition and inhibition of cancer cell growth.
A novel crosstalk between CCAR2 and AKT pathway in the regulation of cancer cell proliferation.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
DNMT1-interacting RNAs block gene-specific DNA methylation.
Cell line, Treatment
View SamplesWe used the microarray analysis to detail the gene expression profile from the leukemic cell line HL-60
DNMT1-interacting RNAs block gene-specific DNA methylation.
Cell line
View SamplesIdentification of the all RNA species associated with DNMT1. Using a comparative genome-scale approach we identified and correlated the RNA species physically associated with DNMT1 and proximal to the annotated genes to the methylation status of the corresponding loci and expression levels of the respective genes. This comparative approach delineated the first -DNMT1 centered- 'epitranscriptome' map, a comprehensive map cross-referencing DNMT1-interacting transcripts to (i) DNA methylation and (ii) gene expression profile. Overall design: Relationship between DNMT1-RNA interactions, DNA methylation and gene expression
DNMT1-interacting RNAs block gene-specific DNA methylation.
Cell line, Subject
View Samples