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  • 1
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    Online Resource
    Antiestrogen-resistant subclones of MCF-7 human breast cancer cells are derived from a common monoclonal drug-resistant progenitor
    Proceedings of the National Academy of Sciences ; 2009
    In:  Proceedings of the National Academy of Sciences Vol. 106, No. 34 ( 2009-08-25), p. 14536-14541
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 106, No. 34 ( 2009-08-25), p. 14536-14541
    Abstract: Emergence of antiestrogen-resistant cells in MCF-7 cells during suppression of estrogen signaling is a widely accepted model of acquired breast cancer resistance to endocrine therapy. To obtain insight into the genomic basis of endocrine therapy resistance, we characterized MCF-7 monoclonal sublines that survived 21-day exposure to tamoxifen (T-series sublines) or fulvestrant (F-series sublines) and sublines unselected by drugs (U-series). All T/F-sublines were resistant to the cytocidal effects of both tamoxifen and fulvestrant. However, their responses to the cytostatic effects of fulvestrant varied greatly, and their remarkably diversified morphology showed no correlation with drug resistance. mRNA expression profiles of the U-sublines differed significantly from those of the T/F-sublines, whose transcriptomal responsiveness to fulvestrant was largely lost. A set of genes strongly expressed in the U-sublines successfully predicted metastasis-free survival of breast cancer patients. Most T/F-sublines shared highly homogeneous genomic DNA aberration patterns that were distinct from those of the U-sublines. Genomic DNA of the U-sublines harbored many aberrations that were not found in the T/F-sublines. These results suggest that the T/F-sublines are derived from a common monoclonal progenitor that lost transcriptomal responsiveness to antiestrogens as a consequence of genetic abnormalities many population doublings ago, not from the antiestrogen-sensitive cells in the same culture during the exposure to antiestrogens. Thus, the apparent acquisition of antiestrogen resistance by MCF-7 cells reflects selection of preexisting drug-resistant subpopulations without involving changes in individual cells. Our results suggest the importance of clonal selection in endocrine therapy resistance of breast cancer.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0907560106
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2009
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  • 2
    Online Resource
    Online Resource
    A Comprehensive Database of Dose-Dependent Transcriptomal Effects of Xenoestrogens in MCF-7 Cells Reveals Biphasic Actions of Bisphenol A Involving a Second Peak of Gene Regulation at a Low Dose Range.
    Oxford University Press (OUP) ; 2012
    In:  Biology of Reproduction Vol. 87, No. Suppl_1 ( 2012-08-01), p. 241-241
    Details
    In: Biology of Reproduction, Oxford University Press (OUP), Vol. 87, No. Suppl_1 ( 2012-08-01), p. 241-241
    Type of Medium: Online Resource
    ISSN: 0006-3363 , 1529-7268
    URL: Article
    DOI: 10.1093/biolreprod/87.s1.241
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2012
    detail.hit.zdb_id: 1469812-2
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  • 3
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    Generation of Human Primordial Germ Cell-like Cells at the Surface of Embryoid Bodies from Primed-pluripotency Induced Pluripotent Stem Cells
    MyJove Corporation ; 2019
    In:  Journal of Visualized Experiments , No. 143 ( 2019-01-11)
    Details
    In: Journal of Visualized Experiments, MyJove Corporation, , No. 143 ( 2019-01-11)
    Type of Medium: Online Resource
    ISSN: 1940-087X
    URL: Article
    DOI: 10.3791/58297
    Language: English
    Publisher: MyJove Corporation
    Publication Date: 2019
    detail.hit.zdb_id: 2259946-0
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  • 4
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    Relevance of iPSC-derived human PGC-like cells at the surface of embryoid bodies to prechemotaxis migrating PGCs
    Proceedings of the National Academy of Sciences ; 2017
    In:  Proceedings of the National Academy of Sciences Vol. 114, No. 46 ( 2017-11-14)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 114, No. 46 ( 2017-11-14)
    Abstract: Pluripotent stem cell-derived human primordial germ cell-like cells (hPGCLCs) provide important opportunities to study primordial germ cells (PGCs). We robustly produced CD38 + hPGCLCs [∼43% of FACS-sorted embryoid body (EB) cells] from primed-state induced pluripotent stem cells (iPSCs) after a 72-hour transient incubation in the four chemical inhibitors (4i)-naïve reprogramming medium and showed transcriptional consistency of our hPGCLCs with hPGCLCs generated in previous studies using various and distinct protocols. Both CD38 + hPGCLCs and CD38 − EB cells significantly expressed PRDM1 and TFAP2C , although PRDM1 mRNA in CD38 − cells lacked the 3′-UTR harboring miRNA binding sites regulating mRNA stability. Genes up-regulated in hPGCLCs were enriched for cell migration genes, and their promoters were enriched for the binding motifs of TFAP2 (which was identified in promoters of T , NANOS3 , and SOX17 ) and the RREB-1 cell adhesion regulator. In EBs, hPGCLCs were identified exclusively in the outermost surface monolayer as dispersed cells or cell aggregates with strong and specific expression of POU5F1/OCT4 protein. Time-lapse live cell imaging revealed active migration of hPGCLCs on Matrigel. Whereas all hPGCLCs strongly expressed the CXCR4 chemotaxis receptor, its ligand CXCL12/SDF1 was not significantly expressed in the whole EBs. Exposure of hPGCLCs to CXCL12/SDF1 induced cell migration genes and antiapoptosis genes. Thus, our study shows that transcriptionally consistent hPGCLCs can be readily produced from hiPSCs after transition of their pluripotency from the primed state using various methods and that hPGCLCs resemble the early-stage PGCs randomly migrating in the midline region of human embryos before initiation of the CXCL12/SDF1-guided chemotaxis.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1707779114
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2017
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  • 5
    Online Resource
    Online Resource
    Generation of Human Primordial Germ Cell-like Cells at the Surface of Embryoid Bodies from Primed-pluripotency Induced Pluripotent Stem Cells
    MyJove Corporation ; 2019
    In:  Journal of Visualized Experiments , No. 143 ( 2019-01-11)
    Details
    In: Journal of Visualized Experiments, MyJove Corporation, , No. 143 ( 2019-01-11)
    Type of Medium: Online Resource
    ISSN: 1940-087X
    URL: Article
    DOI: 10.3791/58297-v
    Language: English
    Publisher: MyJove Corporation
    Publication Date: 2019
    detail.hit.zdb_id: 2259946-0
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  • 6
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    Online Resource
    Erasure of DNA methylation, genomic imprints, and epimutations in a primordial germ-cell model derived from mouse pluripotent stem cells
    Proceedings of the National Academy of Sciences ; 2016
    In:  Proceedings of the National Academy of Sciences Vol. 113, No. 34 ( 2016-08-23), p. 9545-9550
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 113, No. 34 ( 2016-08-23), p. 9545-9550
    Abstract: The genome-wide depletion of 5-methylcytosines (5meCs) caused by passive dilution through DNA synthesis without daughter strand methylation and active enzymatic processes resulting in replacement of 5meCs with unmethylated cytosines is a hallmark of primordial germ cells (PGCs). Although recent studies have shown that in vitro differentiation of pluripotent stem cells (PSCs) to PGC-like cells (PGCLCs) mimics the in vivo differentiation of epiblast cells to PGCs, how DNA methylation status of PGCLCs resembles the dynamics of 5meC erasure in embryonic PGCs remains controversial. Here, by differential detection of genome-wide 5meC and 5-hydroxymethylcytosine (5hmeC) distributions by deep sequencing, we show that PGCLCs derived from mouse PSCs recapitulated the process of genome-wide DNA demethylation in embryonic PGCs, including significant demethylation of imprint control regions (ICRs) associated with increased mRNA expression of the corresponding imprinted genes. Although 5hmeCs were also significantly diminished in PGCLCs, they retained greater amounts of 5hmeCs than intragonadal PGCs. The genomes of both PGCLCs and PGCs selectively retained both 5meCs and 5hmeCs at a small number of repeat sequences such as GSAT_MM, of which the significant retention of bisulfite-resistant cytosines was corroborated by reanalysis of previously published whole-genome bisulfite sequencing data for intragonadal PGCs. PSCs harboring abnormal hypermethylation at ICRs of the Dlk1-Gtl2-Dio3 imprinting cluster diminished these 5meCs upon differentiation to PGCLCs, resulting in transcriptional reactivation of the Gtl2 gene. These observations support the usefulness of PGCLCs in studying the germline epigenetic erasure including imprinted genes, epimutations, and erasure-resistant loci, which may be involved in transgenerational epigenetic inheritance.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1610259113
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2016
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
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  • 7
    Online Resource
    Online Resource
    Expression of Fas ligand in liver metastases of human colonic adenocarcinomas
    Proceedings of the National Academy of Sciences ; 1997
    In:  Proceedings of the National Academy of Sciences Vol. 94, No. 12 ( 1997-06-10), p. 6420-6425
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 94, No. 12 ( 1997-06-10), p. 6420-6425
    Abstract: Fas ligand (FasL) plays a pivotal role in lymphocyte cytotoxicity and the maintenance of immunological homeostasis. Since FasL has been implicated in the existence of immunologically privileged body sites by inducing apoptosis of activated T lymphocytes, we investigated the expression of FasL in human colon cancers. We found that two out of seven primary tumors and all four hepatic metastatic tumors of surgically obtained colonic adenocarcinoma expressed FasL mRNA and protein, detected by reverse transcription-coupled PCR and by immunohistochemical staining, respectively. Expression of FasL was not detected in normal colonic epithelial cells. FasL mRNA was also expressed in some human colonic adenocarcinoma cell lines including SW480, SW1116, and LS180 cells. Cell-surface-associated FasL was detected in these human colon cancer cells by fluorescence immunocytochemical staining. In addition, the expressed FasL was demonstrated to be functional, since coculture experiments using FasL-expressing SW480 cells resulted in apoptosis of Jurkat T leukemia cells that are sensitive to Fas-mediated apoptosis, and this process was specifically inhibited by the neutralizing anti-human FasL antibody. Thus, our findings and other data suggest an alternative mechanism that enables tumors to evade immune destruction by inducing apoptosis in activated T lymphocytes. Furthermore, constitutive expression of FasL in hepatic metastatic tumors suggests that FasL may also be important in their colonization in the liver through induction of apoptosis in the surrounding Fas-expressing hepatocytes.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.94.12.6420
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 1997
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    detail.hit.zdb_id: 1461794-8
    SSG: 11
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  • 8
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    Online Resource
    Global analysis of ligand sensitivity of estrogen inducible and suppressible genes in MCF7/BUS breast cancer cells by DNA microarray
    Proceedings of the National Academy of Sciences ; 2003
    In:  Proceedings of the National Academy of Sciences Vol. 100, No. 24 ( 2003-11-25), p. 13994-13999
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 100, No. 24 ( 2003-11-25), p. 13994-13999
    Abstract: To obtain comprehensive information on 17β-estradiol (E2) sensitivity of genes that are inducible or suppressible by this hormone, we designed a method that determines ligand sensitivities of large numbers of genes by using DNA microarray and a set of simple Perl computer scripts implementing the standard metric statistics. We used it to characterize effects of low (0–100 pM) concentrations of E2 on the transcriptome profile of MCF7/BUS human breast cancer cells, whose E2 dose-dependent growth curve saturated with 100 pM E2. Evaluation of changes in mRNA expression for all genes covered by the DNA microarray indicated that, at a very low concentration (10 pM), E2 suppressed ≈3–5 times larger numbers of genes than it induced, whereas at higher concentrations (30–100 pM) it induced ≈1.5–2 times more genes than it suppressed. Using clearly defined statistical criteria, E2-inducible genes were categorized into several classes based on their E2 sensitivities. This approach of hormone sensitivity analysis revealed that expression of two previously reported E2-inducible autocrine growth factors, transforming growth factor α and stromal cell-derived factor 1, was not affected by 100 pM and lower concentrations of E2 but strongly enhanced by 10 nM E2, which was far higher than the concentration that saturated the E2 dose-dependent growth curve of MCF7/BUS cells. These observations suggested that biological actions of E2 are derived from expression of multiple genes whose E2 sensitivities differ significantly and, hence, depend on the E2 concentration, especially when it is lower than the saturating level, emphasizing the importance of characterizing the ligand dosedependent aspects of E2 actions.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.2235866100
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2003
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    detail.hit.zdb_id: 1461794-8
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  • 9
    Online Resource
    Online Resource
    Cloning of Mouse cited4, a Member of the CITED Family p300/CBP-Binding Transcriptional Coactivators: Induced Expression in Mammary Epithelial Cells
    Elsevier BV ; 2002
    In:  Genomics Vol. 80, No. 6 ( 2002-12), p. 601-613
    Details
    In: Genomics, Elsevier BV, Vol. 80, No. 6 ( 2002-12), p. 601-613
    Type of Medium: Online Resource
    ISSN: 0888-7543
    URL: Article
    DOI: 10.1006/geno.2002.7005
    RVK:
    XA 10000
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2002
    detail.hit.zdb_id: 1468023-3
    SSG: 12
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  • 10
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    Importance of dosage standardization for interpreting transcriptomal signature profiles: Evidence from studies of xenoestrogens
    Proceedings of the National Academy of Sciences ; 2006
    In:  Proceedings of the National Academy of Sciences Vol. 103, No. 32 ( 2006-08-08), p. 12033-12038
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 103, No. 32 ( 2006-08-08), p. 12033-12038
    Abstract: To obtain insights into similarities and differences in the biological actions of related drugs or toxic agents, their transcriptomal signature profiles (TSPs) have been examined in a large number of studies. However, many such reports did not provide proper justification for the dosage criteria of each agent. Using a well characterized cell culture model of estrogen-dependent proliferation of MCF7 human breast cancer cells, we demonstrate how different approaches to dosage standardization exert critical influences on TSPs, leading to different and even conflicting conclusions. Using quantitative cellular response (QCR)-based dosage criteria, TSPs were determined by Affymetrix microarray when cells were proliferating at comparable rates in the presence of various estrogens. We observed that TSPs of the xenoestrogens (e.g., genistein or bisphenol A) were clearly different from the TSP of 17β-estradiol; namely, the former strongly enhanced expression of genes involved in mitochondrial oxidative phosphorylation, whereas the latter showed minimal effects. In contrast, TSPs for genistein and 17β-estradiol were indistinguishable by using the marker gene expression-based dosage criteria, conditions in which there was comparable expression of the mRNA transcripts for the estrogen-inducible WISP2 gene. Our findings indicate that determination and interpretation of TSPs in pharmacogenomic and toxicogenomic studies that examine the transcriptomal actions of related agents by microarray require a clear rationale for the dosage standardization method to be used. We suggest that future studies involving TSP analyses use quantitative and objective dosage standardization methods, such as those with quantitative cellular response or marker gene expression-based dosage criteria.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0605341103
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2006
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
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