Browsing by Subject "Epithelial-Mesenchymal Transition"

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    Nestin Delineates Pancreatic Cancer Stem Cells in Metastatic Foci of NOD/Shi-scid IL2Rγnull (NOG) Mice
    (Elsevier B.V., 2014-03) Matsuda, Yoko; Yoshimura, Hisashi; Ueda, Junji; Naito, Zenya; Korc, Murray; Ishiwata, Toshiyuki; Department of Medicine, IU School of Medicine
    Pancreatic ductal adenocarcinoma (PDAC) is associated with a high incidence of hepatic metastases, as well as occasional pulmonary metastases. To delineate the potential role of cancer stem cells (CSCs) in PDAC metastasis, human PDAC cells were injected into the spleen of mice. The characteristics and expression of markers associated with CSC and epithelial–mesenchymal transition (EMT) of metastatic cells that developed in the liver and lung were then compared with parental cells. The metastatic cells were polygonal, and larger than parental cells. Metastatic cells also exhibited decreased proliferation and increased adhesion to extracellular matrices, as well as enhanced migration and invasion in vitro and increased metastatic capacity in vivo. The CSC markers ALDH1A1, ABCG2, and nestin were expressed at high levels in metastatic cells and exhibited changes consistent with EMT (eg, decreased E-cadherin expression). Moreover, metastatic cells readily formed spheres in culture and exhibited an increased side population by flow analysis. Nestin and ABCG2 were also expressed at high levels in metastatic lesions from PDAC patients, and silencing nestin with shRNA in PDAC cells derived from lung metastases resulted in a marked decrease in the capacity of the cells to form spheres and to yield pulmonary or hepatic metastases. Thus, the metastatic potential of human PDAC cells correlates with CSCs and with EMT characteristics and is dependent on nestin expression.
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    TGF-β induces global changes in DNA methylation during the epithelial-to-mesenchymal transition in ovarian cancer cells
    (Informa UK (Taylor & Francis), 2014-11) Cardenas, Horacio; Vieth, Edyta; Lee, Jiyoon; Segar, Mathew; Liu, Yunlong; Nephew, Kenneth P.; Matei, Daniela; Department of Medicine, IU School of Medicine
    A key step in the process of metastasis is the epithelial-to-mesenchymal transition (EMT). We hypothesized that epigenetic mechanisms play a key role in EMT and to test this hypothesis we analyzed global and gene-specific changes in DNA methylation during TGF-β-induced EMT in ovarian cancer cells. Epigenetic profiling using the Infinium HumanMethylation450 BeadChip (HM450) revealed extensive (P < 0.01) methylation changes after TGF-β stimulation (468 and 390 CpG sites altered at 48 and 120 h post cytokine treatment, respectively). The majority of gene-specific TGF-β-induced methylation changes occurred in CpG islands located in or near promoters (193 and 494 genes hypermethylated at 48 and 120 h after TGF-β stimulation, respectively). Furthermore, methylation changes were sustained for the duration of TGF-β treatment and reversible after the cytokine removal. Pathway analysis of the hypermethylated loci identified functional networks strongly associated with EMT and cancer progression, including cellular movement, cell cycle, organ morphology, cellular development, and cell death and survival. Altered methylation and corresponding expression of specific genes during TGF-β-induced EMT included CDH1 (E-cadherin) and COL1A1 (collagen 1A1). Furthermore, TGF-β induced both expression and activity of DNA methyltransferases (DNMT) -1, -3A, and -3B, and treatment with the DNMT inhibitor SGI-110 prevented TGF-β-induced EMT. These results demonstrate that dynamic changes in the DNA methylome are implicated in TGF-β-induced EMT and metastasis. We suggest that targeting DNMTs may inhibit this process by reversing the EMT genes silenced by DNA methylation in cancer.