scholarly journals The Sda1 Protein Is Required for Passage through Start

2001 ◽  
Vol 12 (1) ◽  
pp. 201-219 ◽  
Author(s):  
Zachary A. Zimmerman ◽  
Douglas R. Kellogg
Keyword(s):  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Critical Role ◽  
Temperature Sensitive ◽  
G1 Cyclins ◽  
Cycle Arrest ◽  
Bud Emergence ◽  
Induce Cell Division

We have used affinity chromatography to identify proteins that interact with Nap1, a protein previously shown to play a role in mitosis. Our studies demonstrate that a highly conserved protein called Sda1 binds to Nap1 both in vitro and in vivo. Loss of Sda1 function causes cells to arrest uniformly as unbudded cells that do not increase significantly in size. Cells arrested by loss of Sda1 function have a 1N DNA content, fail to produce the G1 cyclin Cln2, and remain responsive to mating pheromone, indicating that they arrest in G1 before Start. Expression of CLN2 from a heterologous promoter in temperature-sensitive sda1 cells induces bud emergence and polarization of the actin cytoskeleton, but does not induce cell division, indicating that the sda1 cell cycle arrest phenotype is not due simply to a failure to produce the G1 cyclins. The Sda1 protein is absent from cells arrested in G0 and is expressed before Start when cells reenter the cell cycle, further suggesting that Sda1 functions before Start. Taken together, these findings reveal that Sda1 plays a critical role in G1 events. In addition, these findings suggest that Nap1 is likely to function during G1. Consistent with this, we have found that Nap1 is required for viability in cells lacking the redundant G1 cyclins Cln1 and Cln2. In contrast to a previous study, we have found no evidence that Sda1 is required for the assembly or function of the actin cytoskeleton. Further characterization of Sda1 is likely to provide important clues to the poorly understood mechanisms that control passage through G1.

A Novel Camptothecin Derivative 3j Inhibits Nsclc Proliferation Via Induction of Cell Cycle Arrest By Topo I-Mediated DNA Damage

2019 ◽  
Vol 19 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Yang Liu ◽  
Jingyin Zhang ◽  
Shuyun Feng ◽  
Tingli Zhao ◽  
Zhengzheng Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Cyclin D ◽  
Dna Relaxation ◽  
Cycle Arrest ◽  
H460 Cell ◽  
H1975 Cell

Objective: The aim of this study is to investigate the inhibitory effect of camptothecin derivative 3j on Non-Small Cell Lung Cancer (NSCLCs) cells and the potential anti-tumor mechanisms. Background: Camptothecin compounds are considered as the third largest natural drugs which are widely investigated in the world and they suffered restriction because of serious toxicity, such as hemorrhagic cystitis and bone marrow suppression. Methods: Using cell proliferation assay and S180 tumor mice model, a series of 20(S)-O-substituted benzoyl 7- ethylcamptothecin compounds were screened and evaluated the antitumor activities in vitro and in vivo. Camptothecin derivative 3j was selected for further study using flow cytometry in NSCLCs cells. Cell cycle related protein cyclin A2, CDK2, cyclin D and cyclin E were detected by Western Blot. Then, computer molecular docking was used to confirm the interaction between 3j and Topo I. Also, DNA relaxation assay and alkaline comet assay were used to investigate the mechanism of 3j on DNA damage. Results: Our results demonstrated that camptothecin derivative 3j showed a greater antitumor effect in eleven 20(S)-O-substituted benzoyl 7-ethylcamptothecin compounds in vitro and in vivo. The IC50 of 3j was 1.54± 0.41 µM lower than irinotecan with an IC50 of 13.86±0.80 µM in NCI-H460 cell, which was reduced by 8 fold. In NCI-H1975 cell, the IC50 of 3j was 1.87±0.23 µM lower than irinotecan (IC50±SD, 5.35±0.38 µM), dropped by 1.8 fold. Flow cytometry analysis revealed that 3j induced significant accumulation in a dose-dependent manner. After 24h of 3j (10 µM) treatment, the percentage of NCI-H460 cell in S-phase significantly increased (to 93.54 ± 4.4%) compared with control cells (31.67 ± 3.4%). Similarly, the percentage of NCI-H1975 cell in Sphase significantly increased (to 83.99 ± 2.4%) compared with control cells (34.45 ± 3.9%) after treatment with 10µM of 3j. Moreover, increased levels of cyclin A2, CDK2, and decreased levels of cyclin D, cyclin E further confirmed that cell cycle arrest was induced by 3j. Furthermore, molecular docking studies suggested that 3j interacted with Topo I-DNA and DNA-relaxation assay simultaneously confirmed that 3j suppressed the activity of Topo I. Research on the mechanism showed that 3j exhibited anti-tumour activity via activating the DNA damage response pathway and suppressing the repair pathway in NSCLC cells. Conclusion: Novel camptothecin derivative 3j has been demonstrated as a promising antitumor agent and remains to be assessed in further studies.

EXTH-48. NOVEL COMBINATION THERAPY IN PRECLINICAL GLIOMA MODELS USING THE CELL CYCLE STABILIZING COMPOUND ARGYRIN F AND CHECKPOINT INHIBITION

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi174-vi174
Author(s):  
Bianca Walter ◽  
Denis Canjuga ◽  
Simge G Yuez ◽  
Michael Ghosh ◽  
Przemyslaw Bozko ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Ex Vivo ◽  
Tumor Infiltrating Lymphocytes ◽  
Clonogenic Survival ◽  
Autologous Tumor ◽  
Cycle Arrest ◽  
Resected Tissue ◽  
Infiltrating Lymphocytes

Abstract Glioblastoma are incurable aggressive tumors and remain a therapeutic challenge. Glioblastoma frequently harbor alterations in the retinoblastoma pathway with subsequent cell cycle abnormalities. Here, we aimed to investigate the anti-glioma activity of the cell cycle-stabilizing compound Argyrin F and its potential treatment-induced vulnerabilities to exploit possibilities for novel combination therapies. We investigated cell viability, clonogenic survival, cell cycle status and immunoblots of human and murine glioma cells treated with Argyrin F. Moreover, we established an ex vivo glioma model using residual freshly resected tissue from patients, i.e. patient-derived microtumors (PDMs). Additionally, we extracted autologous tumor infiltrating lymphocytes (TILs) to perform co-culturing experiments. We performed mass spectrometry-based immunopeptidomics and used the orthotopic syngeneic SMA560/VM/Dk glioma mouse model. Argyrin F displayed anti-glioma efficacy in glioma cell lines in vitro and in PDM models ex vivo. Moreover, Argyrin F treatment induced cell cycle arrest, reduced clonogenic survival in vitro and prolonged survival in vivo. Argyrin F-treated SMA560 glioma displayed 4.6-fold more glioma-infiltrating CD8+ T cells. We discovered a distinctive treatment-induced immunopeptidome. Combination of Argyrin F plus PD-1 antibody increased cellular toxicity in PDM/TILs co-cultures ex vivo and prolonged overall survival compared with monotherapies in vivo. We conclude that our experimental data suggest a novel combination of Argyrin F plus PD-1 blockade and its clinical translation.

PGM1 Suppresses Colorectal Cancer Cell Migration And Invasion by Regulating PI3K/ AKT Pathway

2021 ◽  
Author(s):  
Zhewen Zheng ◽  
Xue Zhang ◽  
Jian Bai ◽  
Long Long ◽  
Di Liu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Colony Formation ◽  
Tumor Formation ◽  
Akt Pathway ◽  
Migration And Invasion ◽  
Cycle Arrest ◽  
Cancer Pathogenesis

Abstract BackgroundPhosphoglucomutase 1(PGM1) is known for its involvement in cancer pathogenesis. However, its biological role in colorectal cancer (CRC) is unknown. Here, we studied the functions and mechanisms of PGM1 in CRC.Methods We verified PGM-1 as a DEG by a comprehensive strategy of the TCGA-COAD dataset mining and computational biology. Relative levels of PGM-1 in CRC tumors and adjoining peritumoral tissue were identified by qRT-PCR, WB, and IHC staining in a tissue microarray. PGM1 functions were analyzed using CCK8, EdU, colony formation, cell cycle, apoptosis, and Transwell migration and invasion assays. The influence of PGM1 was further investigated using tumor formation in vivo.ResultsPGM1 mRNA and protein were both reduced in CRC and the reduction was related to CRC pathology and overall survival. PGM1 knockdown stimulated both proliferation and colony formation, promoting cell cycle arrest and apoptosis while overexpression has opposite effects in CRC cells both in vivo and in vitro. Furthermore, we lined the actions of PGM1 to the PI3K/ AKT pathway. ConclusionWe verified that PGM1 suppresses CRC through the PI3K/ AKT pathway. These results suggest the potential for targeting PGM1 in CRC therapies.

scholarly journals Menadione reduces CDC25B expression and promotes tumor shrinkage in gastric cancer

2020 ◽  
Vol 13 ◽  
pp. 175628481989543
Author(s):  
Amanda Braga Bona ◽  
Danielle Queiroz Calcagno ◽  
Helem Ferreira Ribeiro ◽  
José Augusto Pereira Carneiro Muniz ◽  
Giovanny Rebouças Pinto ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Specific Inhibitor ◽  
Gastric Carcinogenesis ◽  
In Vivo Experiments ◽  
Cycle Arrest

Background: Gastric cancer is one of the most incident types of cancer worldwide and presents high mortality rates and poor prognosis. MYC oncogene overexpression is a key event in gastric carcinogenesis and it is known that its protein positively regulates CDC25B expression which, in turn, plays an essential role in the cell division cycle progression. Menadione is a synthetic form of vitamin K that acts as a specific inhibitor of the CDC25 family of phosphatases. Methods: To better understand the menadione mechanism of action in gastric cancer, we evaluated its molecular and cellular effects in cell lines and in Sapajus apella, nonhuman primates from the new world which had gastric carcinogenesis induced by N-Methyl-N-nitrosourea. We tested CDC25B expression by western blot and RT-qPCR. In-vitro assays include proliferation, migration, invasion and flow cytometry to analyze cell cycle arrest. In in-vivo experiments, in addition to the expression analyses, we followed the preneoplastic lesions and the tumor progression by ultrasonography, endoscopy, biopsies, histopathology and immunohistochemistry. Results: Our tests demonstrated menadione reducing CDC25B expression in vivo and in vitro. It was able to reduce migration, invasion and proliferation rates, and induce cell cycle arrest in gastric cancer cell lines. Moreover, our in-vivo experiments demonstrated menadione inhibiting tumor development and progression. Conclusions: We suggest this compound may be an important ally of chemotherapeutics in the treatment of gastric cancer. In addition, CDC25B has proven to be an effective target for investigation and development of new therapeutic strategies for this malignancy.

scholarly journals Epigenetic silencing of CDKN1A and CDKN2B by SNHG1 promotes the cell cycle, migration and epithelial-mesenchymal transition progression of hepatocellular carcinoma

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Bei Li ◽  
Ang Li ◽  
Zhen You ◽  
Jingchang Xu ◽  
Sha Zhu
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Epithelial Mesenchymal Transition ◽  
Critical Role ◽  
Luciferase Assay ◽  
Bioinformatics Analyses ◽  
Mesenchymal Transition ◽  
Rna Immunoprecipitation

Abstract Enhanced SNHG1 (small nucleolar RNA host gene 1) expression has been found to play a critical role in the initiation and progression of hepatocellular carcinoma (HCC) with its detailed mechanism largely unknown. In this study, we show that SNHG1 promotes the HCC progression through epigenetically silencing CDKN1A and CDKN2B in the nucleus, and competing with CDK4 mRNA for binding miR-140-5p in the cytoplasm. Using bioinformatics analyses, we found hepatocarcinogenesis is particularly associated with dysregulated expression of SNHG1 and activation of the cell cycle pathway. SNHG1 was upregulated in HCC tissues and cells, and its knockdown significantly inhibited HCC cell cycle, growth, metastasis, and epithelial–mesenchymal transition (EMT) both in vitro and in vivo. Chromatin immunoprecipitation and RNA immunoprecipitation assays demonstrate that SNHG1 inhibit the transcription of CDKN1A and CDKN2B through enhancing EZH2 mediated-H3K27me3 in the promoter of CDKN1A and CDKN2B, thus resulting in the de-repression of the cell cycle. Dual-luciferase assay and RNA pulldown revealed that SNHG1 promotes the expression of CDK4 by competitively binding to miR-140-5p. In conclusion, we propose that SNHG1 formed a regulatory network to confer an oncogenic function in HCC and SNHG1 may serve as a potential target for HCC diagnosis and treatment.

Bound polyphenol extracted from jujube pulp triggers mitochondria-mediated apoptosis and cell cycle arrest of HepG2 cell in vitro and in vivo

2019 ◽  
Vol 53 ◽  
pp. 187-196 ◽  
Author(s):  
Shuhua Shan ◽  
Yue Xie ◽  
Huiling Zhao ◽  
Jinping Niu ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Hepg2 Cell ◽  
Cycle Arrest

scholarly journals Growth Suppression by Acute PromyelocyticLeukemia-Associated Protein PLZF Is Mediated by Repression ofc-mycExpression

2003 ◽  
Vol 23 (24) ◽  
pp. 9375-9388 ◽  
Author(s):  
Melanie J. McConnell ◽  
Nathalie Chevallier ◽  
Windy Berkofsky-Fessler ◽  
Jena M. Giltnane ◽  
Rupal B. Malani ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Target Genes ◽  
Ectopic Expression ◽  
Growth Suppression ◽  
Quiescent State ◽  
Cycle Arrest

ABSTRACT The transcriptional repressor PLZF was identified by its translocation with retinoic acid receptor alpha in t(11;17) acute promyelocytic leukemia (APL). Ectopic expression of PLZF leads to cell cycle arrest and growth suppression, while disruption of normal PLZF function is implicated in the development of APL. To clarify the function of PLZF in cell growth and survival, we used an inducible PLZF cell line in a microarray analysis to identify the target genes repressed by PLZF. One prominent gene identified was c-myc. The array analysis demonstrated that repression of c-myc by PLZF led to a reduction in c-myc-activated transcripts and an increase in c-myc-repressed transcripts. Regulation of c-myc by PLZF was shown to be both direct and reversible. An interaction between PLZF and the c-myc promoter could be detected both in vitro and in vivo. PLZF repressed the wild-type c-myc promoter in a reporter assay, dependent on the integrity of the binding site identified in vitro. PLZF binding in vivo was coincident with a decrease in RNA polymerase occupation of the c-myc promoter, indicating that repression occurred via a reduction in the initiation of transcription. Finally, expression of c-myc reversed the cell cycle arrest induced by PLZF. These data suggest that PLZF expression maintains a cell in a quiescent state by repressing c-myc expression and preventing cell cycle progression. Loss of this repression through the translocation that occurs in t(11;17) would have serious consequences for cell growth control.

scholarly journals Cell cycle regulation of the yeast Cdc7 protein kinase by association with the Dbf4 protein.

1993 ◽  
Vol 13 (5) ◽  
pp. 2899-2908 ◽  
Author(s):  
A L Jackson ◽  
P M Pahl ◽  
K Harrison ◽  
J Rosamond ◽  
R A Sclafani
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Protein Interactions ◽  
Kinase Activity ◽  
Mitotic Cell ◽  
Common Point ◽  
Temperature Sensitive ◽  
Cdc7 Kinase

Yeast Cdc7 protein kinase and Dbf4 protein are both required for the initiation of DNA replication at the G1/S phase boundary of the mitotic cell cycle. Cdc7 kinase function is stage-specific in the cell cycle, but total Cdc7 protein levels remained unchanged. Therefore, regulation of Cdc7 function appears to be the result of posttranslational modification. In this study, we have attempted to elucidate the mechanism responsible for achieving this specific execution point of Cdc7. Cdc7 kinase activity was shown to be maximal at the G1/S boundary by using either cultures synchronized with alpha factor or Cdc- mutants or with inhibitors of DNA synthesis or mitosis. Therefore, Cdc7 kinase is regulated by a posttranslational mechanism that ensures maximal Cdc7 activity at the G1/S boundary, which is consistent with Cdc7 function in the cell cycle. This cell cycle-dependent regulation could be the result of association with the Dbf4 protein. In this study, the Dbf4 protein was shown to be required for Cdc7 kinase activity in that Cdc7 kinase activity is thermolabile in vitro when extracts prepared from a temperature-sensitive dbf4 mutant grown under permissive conditions are used. In vitro reconstitution assays, in addition to employment of the two-hybrid system for protein-protein interactions, have demonstrated that the Cdc7 and Dbf4 proteins interact both in vitro and in vivo. A suppressor mutation, bob1-1, which can bypass deletion mutations in both cdc7 and dbf4 was isolated. However, the bob1-1 mutation cannot bypass all events in G1 phase because it fails to suppress temperature-sensitive cdc4 or cdc28 mutations. This indicates that the Cdc7 and Dbf4 proteins act at a common point in the cell cycle. Therefore, because of the common point of function for the two proteins and the fact that the Dbf4 protein is essential for Cdc7 function, we propose that Dbf4 may represent a cyclin-like molecule specific for the activation of Cdc7 kinase.

Lobetyol activate MAPK pathways associated with G 1 /S cell cycle arrest and apoptosis in MKN45 cells in vitro and in vivo

2016 ◽  
Vol 81 ◽  
pp. 120-127 ◽  
Author(s):  
Jie Shen ◽  
XinGang Lu ◽  
WangChun Du ◽  
Jun Zhou ◽  
HongFu Qiu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Mapk Pathways ◽  
Cycle Arrest
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