Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA253468 | ENA |
REPOSITORIES: ENA
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Project description:Fucoidan is a high-molecular polysaccharide whose main constituent is sulfated fucose. Extensive studies have demonstrated numerous interesting biological activities for fucoidan. We specifically focused on the anti-proliferation activity of fucoidan and examined the underlying mechanism in MKN45 gastric cancer cells. BrdU assay revealed that fucoidan impeded the MKN45 cell cycle by approximately 50%, and clonogenic assay also showed that fucoidan inhibited cell proliferation. Preliminary examinations of fucoidan using LDH assay showed no immediate cytotoxic effects at 24-h exposure. However, longer time courses revealed inhibition of cell growth at 4 days in a dose-dependent manner. Microarray analysis in MKN45 cells treated with fucoidan identified genes that were upregulated and downregulated in response to fucoidan, including MAP3K5, or ASK1 (apoptosis signal-regulating kinase), which was upregulated by 1.38-fold. Western blot confirmed that fucoidan increased ASK1 protein levels, while reducing the levels of phosphorylated ASK1. Reduction of ASK1 by siRNA decreased proliferation of MKN45 cells. Our findings show that fucoidan may suppress cellular proliferation and DNA synthesis in MKN45 cells by suppressing the ASK1-p38 signaling pathway through reduction of phosphorylated ASK1 levels.
2017-02-09 | GSE58774 | GEO
Project description:Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor that negatively regulates cell survival and proliferation by antagonizing phosphatidylinositol 3-kinase(PI3K)/protein kinase B(PKB/Akt) signaling. Loss of heterozygosity (LOH) of PTEN, reduced expression of PTEN and overexpression of phosphorylated Akt are frequently found in human gastric cancer, and their changes correlate with tumor progression and prognosis. Previous studies have shown that the deregulated miRNAs in human gastric cancer play important roles in gastric cancer cell proliferation, apoptosis and inflammation. However, miRNAs downstream PTEN/Akt signaling is poorly investigated. To clarify whether PTEN is involved in gastric tumorigenesis, we have generated a gastric epithelium specific PTEN knockout mouse which exhibited gastric tumor formation with enhanced cell proliferation.So the objectives of the microarray experiment were to, a) screen miRNAs which might be regulated by PTEN/Akt signaling by comparing the miRNA expression profiles between PTEN deficient and control gastric epithelia. 2) explore the microRNA mechanism involved in gastric cell proliferation and gastric tumorigenesis. miRNA profiling of mouse gastric epithelium,comparing Pten mutant mouse with controls. 4 samples. Experiments in 2 different time point, 20 days and 60 days after birth, 2 Biological replicates. Mutant tissue vs. controls from mixture of 3-4 mouse.
2013-09-02 | E-GEOD-27047 | biostudies-arrayexpress
Project description:In order to explore the effect of miRNA on TRAIL sensitivity of gastric cancer, we selected TRAIL-sensitive MKN45 and TRAIL-resistant BGC823 gastric cancer cell line. The expression of miRNA in MKN45 and BGC823 was detected by miRNA chip. "3" is the miRNA expression file of BGC823. "4" is the miRNA expression file of MKN45.
2020-05-24 | E-MTAB-9151 | biostudies-arrayexpress
Project description:Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor that negatively regulates cell survival and proliferation by antagonizing phosphatidylinositol 3-kinase(PI3K)/protein kinase B(PKB/Akt) signaling. Loss of heterozygosity (LOH) of PTEN, reduced expression of PTEN and overexpression of phosphorylated Akt are frequently found in human gastric cancer, and their changes correlate with tumor progression and prognosis. Previous studies have shown that the deregulated miRNAs in human gastric cancer play important roles in gastric cancer cell proliferation, apoptosis and inflammation. However, miRNAs downstream PTEN/Akt signaling is poorly investigated. To clarify whether PTEN is involved in gastric tumorigenesis, we have generated a gastric epithelium specific PTEN knockout mouse which exhibited gastric tumor formation with enhanced cell proliferation.So the objectives of the microarray experiment were to, a) screen miRNAs which might be regulated by PTEN/Akt signaling by comparing the miRNA expression profiles between PTEN deficient and control gastric epithelia. 2) explore the microRNA mechanism involved in gastric cell proliferation and gastric tumorigenesis.
2013-09-02 | GSE27047 | GEO
Project description:The LIM-only protein FHL2 acts as a transcriptional modulator that positively or negatively regulates multiple signaling pathways. We recently reported that FHL2 cooperates with CBP/p300 in the activation of Ã-catenin/TCF target gene cyclin D1. In this paper, we demonstrate that FHL2 is associated with the cyclin D1 promoter at the TCF/CRE site, providing evidence that cyclin D1 is a direct target of FHL2. We show that deficiency of FHL2 greatly reduces the proliferative capacity of spontaneously immortalized mouse fibroblasts which is associated with decreased expression of cyclin D1 and p16INK4a, and hypophosphorylation of Rb. Reexpression of FHL2 in FHL2-null fibroblasts efficiently restores cyclin D1 levels and cell proliferative capacity, indicating that FHL2 is critical for cyclin D1 activation and cell growth. Moreover, ectopic cyclin D1 expression is sufficient to override growth inhibition of immortalized FHL2-null fibroblasts. Gene expression profiling revealed that FHL2 deficiency triggers a broad change of the cell cycle program that is associated with downregulation of several G1/S and G2/M cyclins, E2F transcription factors and DNA replication machinery, thus correlating with reduced cell proliferation. This change also involves downregulation of the negative cell cycle regulators, particularly INK4 inhibitors, which could counteract the decreased expression of cyclins, allowing cells to grow. Our study illustrates that FHL2 can act on different aspects of the cell cycle program to finely regulate cell proliferation. Experiment Overall Design: Two biological genotypes, FHL2-/- and WT MEF cells. Three spontaneously immortalized clones of each genotype were analyzed using Affymetrix arrays.
2008-06-18 | E-GEOD-10902 | biostudies-arrayexpress
Project description:Persistent colonization of the gastric mucosa by Helicobacter pylori (Hp) elicits chronic inflammation and aberrant epithelial cell proliferation, which increases the risk of gastric cancer. We examined the ability of microRNAs to modulate gastric cell proliferation in response to persistent Hp infection and found that epigenetic silencing of miR-210 plays a key role in gastric disease progression. Importantly, DNA methylation of the miR-210 gene was increased in Hp-positive human gastric biopsies as compared to Hp-negative controls. Moreover silencing of miR-210 in gastric epithelial cells promoted proliferation. We identified STMN1 and DIMT1 as miR-210 target genes and demonstrated that inhibition of miR-210 expression augmented cell proliferation by activating STMN1 and DIMT1. Together, our results highlight inflammation-induced epigenetic silencing of miR-210 as a mechanism of induction of chronic gastric diseases, including cancer, during Hp infection. To identify miR-210 targets in gastric cells, whole transcriptome analysis of AGS and MKN45 cells transfected with pre-miR-210 was conducted using Affymetrix GeneChip Human Genome U133 Plus 2.0 Array.
2014-09-04 | E-GEOD-58004 | biostudies-arrayexpress
Project description:In order to define YAP1-specific gene expression patterns in gastric cancer, the constitutively active mutant YAP1 (YAP1-S127A) was over-expressed in MKN45 gastric cancer cells. Defined gene expression signature was later used to stratify gastric cancer patients according to the presence of the YAP1-activated signature. Three groups of samples are included: 1. Mock control; 2. Vector control; 3. YAP-S127A expression. Gene expression profiles of YAP-S127A mutant-expressing cells were compared to that of mock and vector control. Experiments were done in MKN45 gastric cancer cells.
2013-10-01 | E-GEOD-41387 | biostudies-arrayexpress
Project description:In addition to lipid second messengers derived from the plasma membrane, increasing evidence supports the existence of nuclear lipid-dependent signaling networks. Diacylglycerol is a key second messenger, generated at the nuclear level, which is metabolized by diacylglycerol kinases (DGKs). It has been demonstrated that nuclear DGK-ζ negatively regulates cell cycle progression. The aim of this study was to identify key determinants of nuclear DGK-ζ-dependent cell cycle arrest in C2C12 mouse myoblasts. Using DNA microarrays, Real-Time RT-PCR and western blot, we demonstrated that nuclear DGK-ζ downregulated the expression of cyclin D1 and increased the expression of TIS21/BTG2/PC3, a transcriptional regulator of cyclin D1 with a strong anti-proliferative function. Overexpression of TIS21/BTG2/PC3 blocked the cells in G1 phase of the cell cycle and decreased the levels of Ser807/811 phosphorylated retinoblastoma protein, similarly to overexpression of DGK-ζ. Moreover, during myogenic differentiation of C2C12 cells, we showed an increase of TIS21/BTG2/PC3 expression and a decrease in cyclin D1 levels. siRNA downregulation of TIS21/BTG2/PC3 impaired myogenic differentiation by opposing cell cycle arrest. In summary, these data identify TIS21/BTG2/PC3 and cyclin D1 as downstream effectors of the nuclear DGK-ζ and highlight the importance of this DGK isoform in the regulation of myoblast proliferation and differentiation.
2009-09-30 | GSE11770 | GEO
Project description:To explain the mechanism that miR-29c affects the cell proliferation, we attempted to identify the miR-29c target genes in gastric carcinoma. The expression profiles in MKN45, MKN7 and MKN74 cells transfected with miR-29c oligo or Negative control oligo were obtained from microarray analysis. Then, the genes differentially expressed (Fold change >= 2.0) in miR-29c-transfected cells compared with negative control-transfected ones were identified in each cell lines, respectively. The differentially expressed genes shared among 3 cell lines were identified as the candidates for miR-29c targets. Human gastric cancer cell lines, MKN45, MKN74 and MKN7 were transfected with miR-29c oligo or negative control oligo (n=2) (Ambion). At 24h after, total RNA was extracted and microarray analysis was performed. The genes with common expression changes among three cell lines miR-29c-transfected were identified as the candidates for miR-29c targets.
2013-03-27 | E-GEOD-38581 | biostudies-arrayexpress
Project description:The retinoblastoma tumor suppressor protein (Rb) regulates early G1 phase checkpoints, including the DNA damage response, as well as cell cycle exit and differentiation. The widely accepted model of G1 cell cycle progression proposes that cyclin D:Cdk4/6 partially inactivates the Rb tumor suppressor during early G1 phase by progressive multi-phosphorylation, termed hypo-phosphorylation, resulting in release of E2F transcription factors. However, this model remains largely unproven biochemically and the biologically active form(s) of Rb remains unknown. Here we find that Rb is un-phosphorylated in G0 cells and becomes exclusively mono-phosphorylated throughout all of early G1 phase by cyclin D:Cdk4/6. Early G1 phase mono-phosphorylated Rb is composed of 14 independent isoforms that are all targeted by the E1a oncoprotein, but each shows a preferential binding pattern to specific E2F1-4 transcription factors. At the late G1 Restriction Point, cyclin E:Cdk2 inactivates Rb by a quantum hyper-phosphorylation (>12 phosphates/Rb). Cells undergoing a DNA damage response activate cyclin D:Cdk4/6 to generate mono-phosphorylated Rb that regulates global transcription. In contrast, a non-phosphorylatable ?Cdk-Rb allele was non-functional for regulating a DNA damage response, but functional for driving cell cycle exit and differentiation during myogenesis. These observations fundamentally change our understanding of G1 cell cycle progression and show that there is no progressive multi-phosphorylation or hypo-phosphorylation inactivation of Rb during early G1 phase by cyclin D:Cdk4/6. Instead, cyclin D:Cdk4/6 generates functionally active, mono-phosphorylated Rb that is the only Rb isoform present in cells during early G1 phase. Global transcriptional analysis of murine embryonic fibroblasts (MEFs) with conditional deletion of the endogenous RB gene by treatment with cell permeable TAT-Cre. Comparison to unaltered MEFs and MEFs with physiological level of exogenous wildtype or phospho-mutant RB expressed at time of RB gene deletion.
2014-04-03 | E-GEOD-56453 | biostudies-arrayexpress