scholarly journals A Single Defined Sister Chromatid Fusion Destabilizes Cell Cycle through Micronuclei Formation

2019 ◽  
Author(s):  
Katsushi Kagaya ◽  
Naoto Noma ◽  
Io Yamamoto ◽  
Sanki Tashiro ◽  
Fuyuki Ishikawa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Sister Chromatid ◽  
Chromosome Fusion ◽  
Visualization System ◽  
Multiple Tumor ◽  
Chromosome Fragmentation ◽  
Hierarchical Bayesian Modeling ◽  
Structural Abnormalities ◽  
Fusion Visualization ◽  
Exact Timing

AbstractChromosome fusion is deleterious among oncogenic chromosome rearrangements, and has been proposed to cause multiple tumor-driving abnormalities. Conventional methodologies, however, lack the strictness of the experimental controls on the fusion such as the exact timing, the number and the types of fusion in a given cell. Here, we developed a human cell-based sister chromatid fusion visualization system (FuVis), in which a single defined sister chromatid fusion is induced by CRISPR/Cas9 concomitantly with mCitrine expression. Fused chromosome developed numerical and structural abnormalities, including chromosome fragmentation, an indicative of eventual chromothripsis. Live cell imaging and hierarchical Bayesian modeling indicated that micronucleus (MN) is generated in the first few cell cycle, and that cells with MN tend to possess cell cycle abnormalities. These results demonstrate that, although most cells can tolerate a single fusion, even a single sister chromatid fusion destabilizes cell cycle through MN formation.

scholarly journals Chromosome instability induced by a single defined sister chromatid fusion

2020 ◽  
Vol 3 (12) ◽  
pp. e202000911
Author(s):  
Katsushi Kagaya ◽  
Naoto Noma-Takayasu ◽  
Io Yamamoto ◽  
Sanki Tashiro ◽  
Fuyuki Ishikawa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Sister Chromatid ◽  
Chromosome Instability ◽  
Chromosome Fusion ◽  
Visualization System ◽  
Cell Cycles ◽  
Multiple Tumor ◽  
Experimental Systems ◽  
Chromosome Fusions ◽  
Fusion Visualization

Chromosome fusion is a frequent intermediate in oncogenic chromosome rearrangements and has been proposed to cause multiple tumor-driving abnormalities. In conventional experimental systems, however, these abnormalities were often induced by randomly induced chromosome fusions involving multiple different chromosomes. It was therefore not well understood whether a single defined type of chromosome fusion, which is reminiscent of a sporadic fusion in tumor cells, has the potential to cause chromosome instabilities. Here, we developed a human cell-based sister chromatid fusion visualization system (FuVis), in which a single defined sister chromatid fusion is induced by CRISPR/Cas9 concomitantly with mCitrine expression. The fused chromosome subsequently developed extra-acentric chromosomes, including chromosome scattering, indicative of chromothripsis. Live-cell imaging and statistical modeling indicated that sister chromatid fusion generated micronuclei (MN) in the first few cell cycles and that cells with MN tend to display cell cycle abnormalities. The powerful FuVis system thus demonstrates that even a single sporadic sister chromatid fusion can induce chromosome instability and destabilize the cell cycle through MN formation.

Anti-glioma Efficacy and Mechanism of Action of Tripolinolate A from Tripolium pannonicum

Planta Medica ◽  
2018 ◽  
Vol 84 (11) ◽  
pp. 786-794
Author(s):  
Weiyun Chai ◽  
Lu Chen ◽  
Xiao-Yuan Lian ◽  
Zhizhen Zhang
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Glioma Cells ◽  
Inhibitory Effect ◽  
Cell Cycle Regulators ◽  
Expression Levels ◽  
Multiple Tumor ◽  
Glioma Growth

AbstractTripolinolate A as a new bioactive phenolic ester was previously isolated from a halophyte of Tripolium pannonicum. However, the in vitro and in vivo anti-glioma effects and mechanism of tripolinolate A have not been investigated. This study has demonstrated that (1) tripolinolate A inhibited the proliferation of different glioma cells with IC50 values of 7.97 to 14.02 µM and had a significant inhibitory effect on the glioma growth in U87MG xenograft nude mice, (2) tripolinolate A induced apoptosis in glioma cells by downregulating the expressions of antiapoptotic proteins and arrested glioma cell cycle at the G2/M phase by reducing the expression levels of cell cycle regulators, and (3) tripolinolate A also remarkably reduced the expression levels of several glioma metabolic enzymes and transcription factors. All data together suggested that tripolinolate A had significant in vitro and in vivo anti-glioma effects and the regulation of multiple tumor-related regulators and transcription factors might be responsible for the activities of tripolinolate A against glioma.

scholarly journals Inactivation of multiple tumor-suppressor genes involved in negative regulation of the cell cycle, MTS1/p16INK4A/CDKN2, MTS2/p15INK4B, p53, and Rb genes in primary lymphoid malignancies

Blood ◽  
1996 ◽  
Vol 87 (12) ◽  
pp. 4949-4958 ◽  
Author(s):  
A Hangaishi ◽  
S Ogawa ◽  
N Imamura ◽  
S Miyawaki ◽  
Y Miura ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Tumor Suppressors ◽  
Tumor Suppressor Genes ◽  
Cell Cycle Control ◽  
Negative Regulators ◽  
Suppressor Genes ◽  
Multiple Tumor ◽  
Lymphoid Malignancies ◽  
Cell Cycle Machinery

It is now evident that the cell cycle machinery has a variety of elements negatively regulating cell cycle progression. However, among these negative regulators in cell cycle control, only 4 have been shown to be consistently involved in the development of human cancers as tumor suppressors: Rb (Retinoblastoma susceptibility protein), p53, and two recently identified cyclin-dependent kinase inhibitors, p16INK4A/MTS1 and p15INK4B/MTS2. Because there are functional interrelations among these negative regulators in the cell cycle machinery, it is particularly interesting to investigate the multiplicity of inactivations of these tumor suppressors in human cancers, including leukemias/lymphomas. To address this point, we examined inactivations of these four genes in primary lymphoid malignancies by Southern blot and polymerase chain reaction-single- strand conformation polymorphism analyses. We also analyzed Rb protein expression by Western blot analysis. The p16INK4A and p15INK4B genes were homozygously deleted in 45 and 42 of 230 lymphoid tumor specimens, respectively. Inactivations of the Rb and p53 genes were 27 of 91 and 9 of 173 specimens, respectively. Forty-one (45.1%) of 91 samples examined for inactivations of all four tumor suppressors had one or more abnormalities of these four tumor-suppressor genes, indicating that dysregulation of cell cycle control is important for tumor development. Statistical analysis of interrelations among impairments of these four genes indicated that inactivations of the individual tumor-suppressor genes might occur almost independently. In some patients, disruptions of multiple tumor-suppressor genes occurred; 4 cases with p16INK4A, p15INK4B, and Rb inactivations; 2 cases with p16INK4A, p15INK4B, and p53 inactivations; and 1 case with Rb and p53 inactivations. It is suggested that disruptions of multiple tumor suppressors in a tumor cell confer an additional growth advantage on the tumor.

scholarly journals MicroRNAs in the miR-106b Family Regulate p21/CDKN1A and Promote Cell Cycle Progression

2008 ◽  
Vol 28 (7) ◽  
pp. 2167-2174 ◽  
Author(s):  
Irena Ivanovska ◽  
Alexey S. Ball ◽  
Robert L. Diaz ◽  
Jill F. Magnus ◽  
Miho Kibukawa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Inhibitor ◽  
Phenotype Microarray ◽  
Loss Of Function ◽  
Cycle Progression ◽  
Multiple Tumor ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Expression Of Genes ◽  
Tumor Types

ABSTRACT microRNAs in the miR-106b family are overexpressed in multiple tumor types and are correlated with the expression of genes that regulate the cell cycle. Consistent with these observations, miR-106b family gain of function promotes cell cycle progression, whereas loss of function reverses this phenotype. Microarray profiling uncovers multiple targets of the family, including the cyclin-dependent kinase inhibitor p21/CDKN1A. We show that p21 is a direct target of miR-106b and that its silencing plays a key role in miR-106b-induced cell cycle phenotypes. We also show that miR-106b overrides a doxorubicin-induced DNA damage checkpoint. Thus, miR-106b family members contribute to tumor cell proliferation in part by regulating cell cycle progression and by modulating checkpoint functions.

Induction of autophagy across multiple tumor types through irreversible HER tyrosine kinase blockade.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e13517-e13517
Author(s):  
William Rayford Gwin ◽  
Leihua Liu ◽  
Sumin Zhao ◽  
Wenle Xia ◽  
Neil Spector
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Cellular Proliferation ◽  
Kinase Inhibitor ◽  
Significant Inhibition ◽  
Wild Type ◽  
Multiple Tumor ◽  
Mtorc1 Signaling

e13517 Background: Human epidermal growth factor receptor (HER) receptor tyrosine kinases play a key role in solid tumor oncogenesis. Despite broad expression of HER receptors in solid tumors, HER targeted therapies have not shown significant improvement in survival, calling into question the value of wild-type HER receptors as therapeutic targets. Here we found that an irreversible pan-HER tyrosine kinase inhibitor (TKI), neratinib, but not similar HER TKIs, induced morphologic changes in ovarian, TNBC, and prostate cancer cell lines consistent with induction of autophagy. Methods: SKOV3 (ovarian), OVCAR8 (ovarian), HBL-100 (TNBC), and LAPC4 (prostate) cancer cells were treated with lapatinib, gefitinib, CI-1033, afatinib, and neratinib (0.5mM-2.5mM). The activation state of HER2, EGFR, HER3, Akt, Erk, p70S6, 4EBP1, and Ulk1 was determined by Western blot analysis (WB) at various time points of neratinib treatment. LC3 was analyzed by immunofluorescence (IF) microscopy and WB. Analysis of proliferation, apoptosis, and cell cycle were performed using WST-1, annexin V, and PI staining, respectively. Results: Neratinib, but not similar HER TKIs, induced marked cytoplasmic vacuolization in tumors. The conversion of LC3-I to LC3-II in neratinib-treated cells was consistent with induction of autophagy. Moreover, PI3K/Akt, MAPK/Erk1/2 and mTORC1 signaling cascades were inhibited in neratinib-treated cells, and were associated with the inhibition of phospho-Ulk1, a key step in autophagy initiation. Treatment with neratinib alone resulted in G1 cell cycle arrest. Importantly, the combination of neratinib and chloroquine, an autophagy inhibitor, induced a statistically significant inhibition of cellular proliferation (p <0.01) and increased apoptosis compared to treatment with either drug alone. Conclusions: Our data suggest that more effective inhibition of wild-type HER receptors, can lead to mTORC1 inhibition, which in turn triggers autophagy. Here, autophagy appears to protect cells rather than inducing apoptosis. Consequently, targeting both HER receptors and autophagy represents an attractive therapeutic strategy to treat tumors expressing wild-type HER receptors.

Sign in / Sign up

Export Citation Format

Share Document