scholarly journals Human Herpesvirus-6 U14 Induces Cell-Cycle Arrest in G2/M Phase by Associating with a Cellular Protein, EDD

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137420 ◽  
Author(s):  
Junko Mori ◽  
Akiko Kawabata ◽  
Huamin Tang ◽  
Kenjiro Tadagaki ◽  
Hiroyuki Mizuguchi ◽  
...  
2010 ◽  
Vol 84 (15) ◽  
pp. 7683-7694 ◽  
Author(s):  
Julius L. C. Chulu ◽  
Wei R. Huang ◽  
L. Wang ◽  
Wen L. Shih ◽  
Hung J. Liu

ABSTRACT The effects of avian reovirus (ARV) p17 protein on cell cycle progression and host cellular protein translation were studied. ARV infection and ARV p17 transfection resulted in the accumulation of infected and/or transfected cells in the G2/M phase of the cell cycle. The accumulation of cells in the G2/M phase was accompanied by upregulation and phosphorylation of the G2/M-phase proteins ATM, p53, p21cip1/waf1, Cdc2, cyclin B1, Chk1, Chk2, and Cdc25C, suggesting that p17 induces a G2/M cell cycle arrest through activation of the ATM/p53/p21cip1/waf1/Cdc2/cyclin B1 and ATM/Chk1/Chk2/Cdc25C pathways. The G2/M cell cycle arrest resulted in increased virus replication. In the present study, we also provide evidence demonstrating that p17 protein is responsible for ARV-induced host cellular protein translation shutoff. Increased phosphorylation levels of the eukaryotic translation elongation factor 2 (eEF2) and initiation factor eIF2α and reduced phosphorylation levels of the eukaryotic translation initiation factors eIF4E, eIF4B, and eIF4G, as well as 4E-BP1 and Mnk-1 in p17-transfected cells, demonstrated that ARV p17 suppresses translation initiation factors and translation elongation factors to induce host cellular protein translation shutoff. Inhibition of mTOR by rapamycin resulted in a decrease in the levels of phosphorylated 4E-BP1, eIF4B, and eIF4G and an increase in the levels eEF2 but did not affect ARV replication, suggesting that ARV replication was not hindered by inhibition of cap-dependent translation. Taken together, our data indicate that ARV p17-induced G2/M arrest and host cellular translation shutoff resulted in increased ARV replication.


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 501
Author(s):  
So Hyun Park ◽  
Ji-Young Hong ◽  
Hyen Joo Park ◽  
Sang Kook Lee

Oxypeucedanin (OPD), a furocoumarin compound from Angelica dahurica (Umbelliferae), exhibits potential antiproliferative activities in human cancer cells. However, the underlying molecular mechanisms of OPD as an anticancer agent in human hepatocellular cancer cells have not been fully elucidated. Therefore, the present study investigated the antiproliferative effect of OPD in SK-Hep-1 human hepatoma cells. OPD effectively inhibited the growth of SK-Hep-1 cells. Flow cytometric analysis revealed that OPD was able to induce G2/M phase cell cycle arrest in cells. The G2/M phase cell cycle arrest by OPD was associated with the downregulation of the checkpoint proteins cyclin B1, cyclin E, cdc2, and cdc25c, and the up-regulation of p-chk1 (Ser345) expression. The growth-inhibitory activity of OPD against hepatoma cells was found to be p53-dependent. The p53-expressing cells (SK-Hep-1 and HepG2) were sensitive, but p53-null cells (Hep3B) were insensitive to the antiproliferative activity of OPD. OPD also activated the expression of p53, and thus leading to the induction of MDM2 and p21, which indicates that the antiproliferative activity of OPD is in part correlated with the modulation of p53 in cancer cells. In addition, the combination of OPD with gemcitabine showed synergistic growth-inhibitory activity in SK-Hep-1 cells. These findings suggest that the anti-proliferative activity of OPD may be highly associated with the induction of G2/M phase cell cycle arrest and upregulation of the p53/MDM2/p21 axis in SK-HEP-1 hepatoma cells.


2022 ◽  
Author(s):  
Selvaraj Shyamsivappan ◽  
Raju Vivek ◽  
Thangaraj Suresh ◽  
Palanivel Naveen ◽  
Kaviyarasu Adhigaman ◽  
...  

A progression of new N-(3'-acetyl-8-nitro-2,3-dihydro-1H,3'H-spiro[quinoline-4,2'-[1,3,4]thiadiazol]-5'-yl) acetamide derivatives were synthesized from potent 8-nitro quinoline-thiosemicarbazones. The synthesized compounds were characterized by different spectroscopic studies and single X-ray crystallographic studies. The compounds were...


2002 ◽  
Vol 49 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Justyna Gołebiewska ◽  
Piotr Rozwadowski ◽  
Jan Henryk Spodnik ◽  
Narcyz Knap ◽  
Takashi Wakabayashi ◽  
...  

We have demonstrated for the first time that the steroid metabolite, 2-methoxyestradiol (2-ME) is a powerful growth inhibitor of human osteosarcoma 143 B cell line by pleiotropic mechanisms involving cell cycle arrest at two different points and apoptosis. The ability of 2-ME to inhibit cell cycle at the respective points has been found concentration dependent. 1 microM 2-ME inhibited cell cycle at G1 phase while 10 microM 2-ME caused G2/M cell cycle arrest. As a natural estrogen metabolite 2-ME is expected to perturb the stability of microtubules (MT) in vivo analogously to Taxol--the MT binding anticancer agent. Contrary to 2-ME, Taxol induced accumulation of osteosarcoma cells in G2/M phase of cell cycle only. The presented data strongly suggest two different mechanisms of cytotoxic action of 2-ME at the level of a single cell.


2005 ◽  
Vol 79 (5) ◽  
pp. 2780-2787 ◽  
Author(s):  
Tomoshige Kino ◽  
Alexander Gragerov ◽  
Antonio Valentin ◽  
Maria Tsopanomihalou ◽  
Galina Ilyina-Gragerova ◽  
...  

ABSTRACT Vpr and selected mutants were used in a Saccharomyces cerevisiae two-hybrid screen to identify cellular interactors. We found Vpr interacted with 14-3-3 proteins, a family regulating a multitude of proteins in the cell. Vpr mutant R80A, which is inactive in cell cycle arrest, did not interact with 14-3-3. 14-3-3 proteins regulate the G2/M transition by inactivating Cdc25C phosphatase via binding to the phosphorylated serine residue at position 216 of Cdc25C. 14-3-3 overexpression in human cells synergized with Vpr in the arrest of cell cycle. Vpr did not arrest efficiently cells not expressing 14-3-3σ. This indicated that a full complement of 14-3-3 proteins is necessary for optimal Vpr function on the cell cycle. Mutational analysis showed that the C-terminal portion of Vpr, known to harbor its cell cycle-arresting activity, bound directly to the C-terminal part of 14-3-3, outside of its phosphopeptide-binding pocket. Vpr expression shifted localization of the mutant Cdc25C S216A to the cytoplasm, indicating that Vpr promotes the association of 14-3-3 and Cdc25C, independently of the presence of serine 216. Immunoprecipitations of cell extracts indicated the presence of triple complexes (Vpr/14-3-3/Cdc25C). These results indicate that Vpr promotes cell cycle arrest at the G2/M phase by facilitating association of 14-3-3 and Cdc25C independently of the latter's phosphorylation status.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Li Yin ◽  
Jing Wu ◽  
Jianfeng Wu ◽  
Jinjun Ye ◽  
Xuesong Jiang ◽  
...  

This study aims to evaluate the radiosensitization effect of nedaplatin on nasopharyngeal carcinoma (NPC) cell lines with different Epstein-Barr virus (EBV) status. Human NPC cell lines CNE-2 (EBV-negative) and C666 (EBV-positive) were treated with 0–100 μg/mL nedaplatin, and inhibitory effects on cell viability and IC50were calculated by MTS assay. We assessed changes in radiosensitivity of cells by MTS and colony formation assays, and detected the apoptosis index and changes in cell cycle by flow cytometry. MTS assay showed that nedaplatin caused significant cytotoxicity in CNE-2 and C666 cells in a time- and dose-dependent manner. After 24 h, nedaplatin inhibited growth of CNE-2 and C666 cells with IC50values of 34.32 and 63.69 μg/mL, respectively. Compared with radiation alone, nedaplatin enhanced the radiation effect on both cell lines. Nedaplatin markedly increased apoptosis and cell cycle arrest in G2/M phase. Nedaplatin radiosensitized human NPC cells CNE-2 and C666, with a significantly greater effect on the former. The mechanisms of radiosensitization include induction of apoptosis and enhancement of cell cycle arrest in G2/M phase.


1998 ◽  
Vol 335 (1) ◽  
pp. 43-50
Author(s):  
Dong-Hua CHEN ◽  
Chin-Tin CHEN ◽  
Yong ZHANG ◽  
Mei-Ann LIU ◽  
Roberto CAMPOS-GONZALEZ ◽  
...  

We have shown previously that oncogenic Ras induces cell cycle arrest in activated Xenopus egg extracts [Pan, Chen and Lin (1994) J. Biol. Chem. 269, 5968–5975]. The cell cycle arrest correlates with the stimulation of a protein kinase activity that phosphorylates histone H2b in vitro (designated p96h2bk) [Chen and Pan (1994) J. Biol. Chem. 269, 28034–28043]. We report here that p96h2bk is likely to be p96ram, a protein of approx. 96 kDa that immunoreacts with a monoclonal antibody (Mk-1) raised against a synthetic peptide derived from a sequence highly conserved in Erk1/Erk2 (where Erk is extracellular-signal-regulated kinase). This is supported by two lines of evidence. First, activation/inactivation of p96h2bk correlates with upward/downward bandshifts of p96ram in polyacrylamide gels. Secondly, both p96h2bk and p96ram can be immunoprecipitated by antibody Mk-1. We also studied the activity of p96h2bk/p96ram in Xenopus oocytes and eggs. p96h2bk/p96ram was inactive in stage 6 oocytes, was active in unfertilized eggs, and became inactive again in eggs after fertilization. Since stage 6 oocytes are at G2-phase of the cell cycle, unfertilized eggs arrest at M-phase and eggs exit M-phase arrest after fertilization, the results thus indicate that p96h2bk/p96ram activity is cell cycle dependent. Moreover, microinjection of oncogenic Ras into fertilized eggs at the one-cell stage arrests the embryos at the two-cell stage, and this induced arrest is correlated with an inappropriate activation of p96h2bk/p96ram. The data are consistent with the concept that inappropriate activation of p96h2bk/p96ram plays a role in the cell cycle arrest induced by oncogenic Ras.


2021 ◽  
Author(s):  
Selvaraj Shyamsivappan ◽  
Raju Vivek ◽  
Thangaraj Suresh ◽  
Adhigaman Kaviyarasu ◽  
Sundarasamy Amsaveni ◽  
...  

Abstract A progression of novel thiadiazoline spiro quinoline derivatives were synthesized from potent thiadiazoline spiro quinoline derivatives . The synthesized compounds portrayed by different spectroscopic studies and single X-ray crystallographic studies. The compounds were assessed for in vitro anticancer properties towards MCF-7 and HeLa cells. The compounds showed superior inhibition action MCF-7 malignant growth cells. Amongst, the compound 4a showed significant inhibition activity, the cell death mechanism was evaluated by fluorescent staining, and flow cytometry, RT-PCR, and western blot analyses. The in vitro anticancer results revealed that the compound 4a induced apoptosis by inhibition of estrogen receptor alpha (ERα) and G2/M phase cell cycle arrest. The binding affinity of the compounds with ERα and pharmacokinetic properties were confirmed by molecular docking studies.


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