Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA260209 | ENA |
REPOSITORIES: ENA
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Project description:Non mitotic tumor cells are resistant to conventional chemotherapeutic drugs. However, the mechanisms underlying this phenomenon remain unclear. Here, we found a population that is viable but remains in the G1 phase for an extended period of time (up to 48 h) by Long-term time-lapse observations in Fucci-HCT116 cells and then we conducted DNA microarray-based comparative analyses between the RR (the long-term G1-arrested cells) and R (the G1-arrested cells) fractions, to determine the molecular basis of the G1 arrest/maintenance mechanism. This study is related to GSE34940.
2015-01-27 | GSE61088 | GEO
Project description:Non mitotic tumor cells are resistant to conventional chemotherapeutic drugs. However, the mechanisms underlying this phenomenon remain unclear. Here, we found a population that is viable but remains in the G1 phase for an extended period of time (up to 48 h) by Long-term time-lapse observations in Fucci-HCT116 cells and then we conducted DNA microarray-based comparative analyses between the RR (the long-term G1-arrested cells) and R (the G1-arrested cells) fractions, to determine the molecular basis of the G1 arrest/maintenance mechanism. This study is related to GSE34940. The labeled cRNAs were hybridized on 4X44K v2 Agilent Whole Human Genome dual color Microarrays (G4845A) in two dye swap experiments, resulting in four individual microarrays.
2015-01-27 | E-GEOD-61088 | biostudies-arrayexpress
Project description:Cell size and the cell cycle are intrinsically coupled and abnormal increases in cell size are associated with senescence and permanent cell cycle arrest. The mechanism by which overgrowth primes cells to withdraw from the cell cycle remains unknown. We investigate this here using CDK4/6 inhibitors that arrest cell cycle progression during G0/G1 and are used in the clinic to treat ER+/HER2- metastatic breast cancer. We demonstrate that CDK4/6 inhibition promotes cellular overgrowth during G0/G1, causing p38MAPK-p53-p21-dependent cell cycle withdrawal. We find that cell cycle withdrawal is triggered by two waves of p21 induction. First, overgrowth during a long-term G0/G1 arrest induces an osmotic stress response. This stress response produces the first wave of p21 induction. Second, when CDK4/6 inhibitors are removed, a fraction of cells escape long term G0/G1 arrest and enter S-phase where overgrowth-driven replication stress results in a second wave of p21 induction that causes cell cycle withdrawal from G2, or the subsequent G1. We propose a model whereby both waves of p21 induction contribute to promote permanent cell cycle arrest. This model could explain why cellular hypertrophy is associated with senescence and why CDK4/6 inhibitors have long-lasting effects in patients.
2023-11-27 | PXD036519 | Pride
Project description:Early after infection, Epstein-Barr Virus (EBV) induces a transient period of hyper-proliferation that is suppressed by the activation of the DNA damage response and a G1/S phase growth arrest. This growth arrest prevents long-term outgrowth of the majority of infected cells. We developed a method to isolate and characterize infected cells that arrest after this early burst of proliferation. We used microarray analysis to uncover changes in gene expression that could give us a better understanding of the pathways that attenuate immortalization. Human PBMCs were labeled with CellTrace Violet and infected with the B95-8 strain of EBV. At 4 days post-infection, the cells were labeled with a second proliferation dye, CFSE. Cells that proliferated are called PP and those that initially proliferated and then arrested are called PA. Total mRNA was isolated from sorted PA and PP cells using an RNeasy kit . The RNA was processed using an Ambion MessageAmp Premier Package and hybridized to a Human Genome U133 Plus. 2.0 Chip by the Duke Center for Genomic and Computational Biology Microarray Core. The resultant CEL files were RMA normalized (Partek) and the data was analyzed with GenePattern and GSEA v2.
2015-12-19 | E-GEOD-76137 | biostudies-arrayexpress
Project description:Immuno-histochemistry for RelA in breast tumors revealed a range of staining intensity and negative correlation between RelA levels and proliferation-index in estrogen receptor-positive tumors. Conditional expression of RelA arrested proliferation in primary mammary and fallopian tube epithelial cells. RelA dependent CDK4 downregulation was responsible for activating the G1/S checkpoint and cell cycle arrest. RelA target genes, including Interferon Response Factors (IRF), were up-regulated in the arrested cells. Among the IRFs, IRF1 expression correlates with RelA expression. Suppressing IRF1 restored CDK4 levels and rescued RelA-dependent proliferation arrest analogous to abrogating the G1/S checkpoint or restoring CDK4 levels. Apart from cyclins, regulation of CDK4 by the RelA-IRF1 transcriptional network controls proliferation of breast tumors and predicts sensitivity to a CDK4/6 inhibitor.
2015-09-26 | GSE65040 | GEO
Project description:Here, we investigate gene expression response of the BRAFV600E mutant cell line COLO205 to the MEK inhibitor selumetinib / AZD6244 / ARRY-142886. Although selumetinib causes long term G1 arrest, we observe cells stochastically entering the cell cycle without re-activation of ERK and initiation of a normal proliferative gene expression programme. Genes encoding DNA replication and repair factors are downregulated during G1 arrest, but many of these are transiently induced when cells escaping arrest enter S and G2. Nonetheless, mRNAs encoding key DNA replication factors including the MCM replicative helicase complex, PCNA and TIPIN remain at very low abundance.
2021-09-12 | GSE183859 | GEO
Project description:Here, we investigate gene expression response of the BRAFV600E mutant cell line COLO205 to the MEK inhibitor selumetinib / AZD6244 / ARRY-142886. Although selumetinib causes long term G1 arrest, we observe cells stochastically entering the cell cycle without re-activation of ERK and initiation of a normal proliferative gene expression programme. Genes encoding DNA replication and repair factors are downregulated during G1 arrest, but many of these are transiently induced when cells escaping arrest enter S and G2. Nonetheless, mRNAs encoding key DNA replication factors including the MCM replicative helicase complex, PCNA and TIPIN remain at very low abundance.
2021-03-23 | GSE168602 | GEO
Project description:A long-term goal in cancer research has been to inhibit the cell cycle in tumour cells without causing toxicity in proliferative healthy tissues. The best evidence that this is achievable is provided by CDK4/6 inhibitors, which arrest the cell cycle in G1, are well-tolerated in patients, and are effective in treating ER+/HER2- breast cancer. CDK4/6 inhibitors are effective because they arrest tumour cells more efficiently than some healthy cell types and, in addition, they affect the tumour microenvironment to enhance anti-tumour immunity. We demonstrate here another reason to explain their efficacy. Tumour cells are specifically vulnerable to CDK4/6 inhibition because during the G1 arrest, oncogenic signals drive toxic cell overgrowth. This overgrowth causes permanent cell cycle withdrawal by either preventing progression from G1 or by inducing replication stress and genotoxic damage during the subsequent S-phase and mitosis. Inhibiting or reverting oncogenic signals that converge onto mTOR can rescue this excessive growth, DNA damage and cell cycle exit in cancer cells. Conversely, inducing oncogenic signals in non-transformed cells can drive these toxic phenotypes and sensitize cells to CDK4/6 inhibition. Together, this demonstrates how oncogenic signals that have evolved to stimulate constitutive tumour growth and proliferation driven subverted to cause toxic cell growth and irreversible cell cycle exit when proliferation is halted in G1.
2023-11-17 | PXD043792 | Pride
Project description:Cellular proliferation is highly regulated to ensure proper tissue homeostasis and to prevent diseases such as cancer. In actively proliferating cells, entry into S phase of the cell cycle and initiation of DNA replication is promoted by inactivation of the E3 ubiquitin ligase APC/C (anaphase promoting complex/cyclosome), though the critical S phase-promoting substrates have not been fully elucidated. The APC/C is also active in cells that have exited the cell cycle and entered an arrested state, but whether APC/C activity is essential to maintain arrest is unclear. We found that APC/C inactivation is sufficient to bypass cellular arrest induced by the CDK4/6 inhibitor Palbociclib. To identify potential APC/C substrates responsible for driving the escape from cell cycle arrest, we arrested cells using Palbociclib and then induced EMI1, inactivating the APC/C. Samples were collected at 0, 8, 16 and 20h after arrest and analyzed using proteomics. We found that inactivation of the APC/C promotes cell cycle re-entry by inducing RB phosphorylation and E2F-dependent gene transcription. Stabilization of both cyclin A and cyclin B contributes to arrest bypass, but only cyclin A accumulation is absolutely required. Direct expression of APC/C-resistant cyclin A, but not cyclin B, in arrested cells induces S phase entry analogous to APC/C inactivation. Cells bypassing arrest initiate DNA replication with severely reduced origin licensing, at least in part due to premature geminin accumulation. As a result, cells exhibit reduced rates of DNA synthesis, which leads to the accumulation of replication stress and long-term proliferation defects. Our findings suggest that CDK4/6 inhibition in cancers with reduced APC/C activity may be ineffective at promoting cytostatic cell cycle arrest but may nonetheless lead to elevated levels of replication stress that ultimately leads to a more durable cell cycle withdrawal.
2024-07-18 | PXD046783 | Pride
Project description:Early after infection, Epstein-Barr Virus (EBV) induces a transient period of hyper-proliferation that is suppressed by the activation of the DNA damage response and a G1/S phase growth arrest. This growth arrest prevents long-term outgrowth of the majority of infected cells. We developed a method to isolate and characterize infected cells that arrest after this early burst of proliferation. We used microarray analysis to uncover changes in gene expression that could give us a better understanding of the pathways that attenuate immortalization.
2015-12-19 | GSE76137 | GEO