scholarly journals Oxidation state governs structural transitions in peroxiredoxin II that correlate with cell cycle arrest and recovery

2006 ◽  
Vol 175 (5) ◽  
pp. 779-789 ◽  
Author(s):  
Timothy J. Phalen ◽  
Kelly Weirather ◽  
Paula B. Deming ◽  
Vikas Anathy ◽  
Alan K. Howe ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hydrogen Peroxide ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Ectopic Expression ◽  
Structural Transitions ◽  
Mitogenic Signaling ◽  
Cycle Arrest ◽  
Subcellular Processes ◽  
Dependent Cell

Inactivation of eukaryotic 2-Cys peroxiredoxins (Prxs) by hyperoxidation has been proposed to promote accumulation of hydrogen peroxide (H2O2) for redox-dependent signaling events. We examined the oxidation and oligomeric states of PrxI and -II in epithelial cells during mitogenic signaling and in response to fluxes of H2O2. During normal mitogenic signaling, hyperoxidation of PrxI and -II was not detected. In contrast, H2O2-dependent cell cycle arrest was correlated with hyperoxidation of PrxII, which resulted in quantitative recruitment of ∼66- and ∼140-kD PrxII complexes into large filamentous oligomers. Expression of cyclin D1 and cell proliferation did not resume until PrxII-SO2H was reduced and native PrxII complexes were regenerated. Ectopic expression of PrxI or -II increased Prx-SO2H levels in response to oxidant exposure and failed to protect cells from arrest. We propose a model in which Prxs function as peroxide dosimeters in subcellular processes that involve redox cycling, with hyperoxidation controlling structural transitions that alert cells of perturbations in peroxide homeostasis.

scholarly journals Aberrant Expression of Nucleostemin Activates p53 and Induces Cell Cycle Arrest via Inhibition of MDM2

2008 ◽  
Vol 28 (13) ◽  
pp. 4365-4376 ◽  
Author(s):  
Mu-Shui Dai ◽  
Xiao-Xin Sun ◽  
Hua Lu
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Ribosomal Proteins ◽  
Cell Cycle Checkpoint ◽  
Aberrant Expression ◽  
Cycle Arrest ◽  
Reduce Cell Proliferation ◽  
Cycle Checkpoint ◽  
Dependent Cell

ABSTRACT The nucleolar protein nucleostemin (NS) is essential for cell proliferation and early embryogenesis. Both depletion and overexpression of NS reduce cell proliferation. However, the mechanisms underlying this regulation are still unclear. Here, we show that NS regulates p53 activity through the inhibition of MDM2. NS binds to the central acidic domain of MDM2 and inhibits MDM2-mediated p53 ubiquitylation and degradation. Consequently, ectopic overexpression of NS activates p53, induces G1 cell cycle arrest, and inhibits cell proliferation. Interestingly, the knockdown of NS by small interfering RNA also activates p53 and induces G1 arrest. These effects require the ribosomal proteins L5 and L11, since the depletion of NS enhanced their interactions with MDM2 and the knockdown of L5 or L11 abrogated the NS depletion-induced p53 activation and cell cycle arrest. These results suggest that a p53-dependent cell cycle checkpoint monitors changes of cellular NS levels via the impediment of MDM2 function.

scholarly journals miR-34a directly targets tRNAiMet precursors and affects cellular proliferation, cell cycle, and apoptosis

2018 ◽  
Vol 115 (28) ◽  
pp. 7392-7397 ◽  
Author(s):  
Bo Wang ◽  
Dongping Li ◽  
Igor Kovalchuk ◽  
Ingrid J. Apel ◽  
Arul M. Chinnaiyan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Breast Cancer Cells ◽  
Cellular Proliferation ◽  
Ectopic Expression ◽  
Breast Carcinogenesis ◽  
Argonaute 2 ◽  
Cycle Arrest

It remains unknown whether microRNA (miRNA/miR) can target transfer RNA (tRNA) molecules. Here we provide evidence that miR-34a physically interacts with and functionally targets tRNAiMet precursors in both in vitro pulldown and Argonaute 2 (AGO2) cleavage assays. We find that miR-34a suppresses breast carcinogenesis, at least in part by lowering the levels of tRNAiMet through AGO2-mediated repression, consequently inhibiting the proliferation of breast cancer cells and inducing cell cycle arrest and apoptosis. Moreover, miR-34a expression is negatively correlated with tRNAiMet levels in cancer cell lines. Furthermore, we find that tRNAiMet knockdown also reduces cell proliferation while inducing cell cycle arrest and apoptosis. Conversely, ectopic expression of tRNAiMet promotes cell proliferation, inhibits apoptosis, and accelerates the S/G2 transition. Moreover, the enforced expression of modified tRNAiMet completely restores the phenotypic changes induced by miR-34a. Our results demonstrate that miR-34a directly targets tRNAiMet precursors via AGO2-mediated cleavage, and that tRNAiMet functions as an oncogene, potentially representing a target molecule for therapeutic intervention.

scholarly journals Induction of apoptosis and cell cycle arrest by chloroform fraction of Juniperus phoenicea and chemical constituents analysis

2021 ◽  
Vol 19 (1) ◽  
pp. 119-127
Author(s):  
Ibrahim O. Barnawi ◽  
Fahd A. Nasr ◽  
Omar M. Noman ◽  
Ali S. Alqahtani ◽  
Mohammed Al-zharani ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Cancer Cells ◽  
Chloroform Fraction ◽  
Active Fraction ◽  
Cycle Arrest ◽  
Juniperus Phoenicea ◽  
Medicinal Properties ◽  
Mcf 7

Abstract Different phytochemicals from various plant species exhibit promising medicinal properties against cancer. Juniperus phoenicea is a plant species that has been found to present medicinal properties. Herein, crude extract and fractions of J. phoenicea were examined to determine its anticancer properties against several cancer cells. The active fraction was chosen to assess its activity on cell cycle progression and apoptosis induction by annexin and propidium iodide (PI) biomarkers. Further, phytochemical screening for possible contents of active fraction using gas chromatography–mass spectrometry (GC-MS) analysis was conducted. It was demonstrated that cell proliferation was suppressed, and the MCF-7 cell line was the most sensitive to J. phoenicea chloroform fraction (JPCF), with the IC50 values of 24.5 μg/mL. The anti-proliferation activity of JPCF in MCF-7 cells was linked to the aggregation of cells in the G1 phase, increases in early and late apoptosis as well as necrotic cell death. Contents analysis of JPCF using GC-MS analysis identified 3-methyl-5-(2′,6′,6′-trimethylcyclohex-1′-enyl)-1-penten-3-ol (16.5%), methyl 8-oxooctanoate (15.61%), cubenol (13.48%), and 7-oxabicyclo [2.2.1] heptane (12.14%) as major constituents. Our present study provides clear evidence that J. phoenicea can inhibit cell proliferation, trigger cell cycle arrest, and induce apoptosis in tested cancer cells.

scholarly journals Hyperbaric oxygen promotes not only glioblastoma proliferation but also chemosensitization by inhibiting HIF1α/HIF2α-Sox2

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pan Wang ◽  
Sheng Gong ◽  
Jinyu Pan ◽  
Junwei Wang ◽  
Dewei Zou ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Hyperbaric Oxygen ◽  
Cell Cycle Progression ◽  
Malignant Progression ◽  
Cycle Progression ◽  
Chemotherapy Sensitivity ◽  
Hypoxic Conditions ◽  
Cycle Arrest

AbstractThere exists a consensus that combining hyperbaric oxygen (HBO) and chemotherapy promotes chemotherapy sensitivity in GBM cells. However, few studies have explored the mechanism involved. HIF1α and HIF2α are the two main molecules that contribute to GBM malignant progression by inhibiting apoptosis or maintaining stemness under hypoxic conditions. Moreover, Sox2, a marker of stemness, also contributes to GBM malignant progression through stemness maintenance or cell cycle arrest. Briefly, HIF1α, HIF2α and Sox2 are highly expressed under hypoxia and contribute to GBM growth and chemoresistance. However, after exposure to HBO for GBM, whether the expression of the above factors is decreased, resulting in chemosensitization, remains unknown. Therefore, we performed a series of studies and determined that the expression of HIF1α, HIF2α and Sox2 was decreased after HBO and that HBO promoted GBM cell proliferation through cell cycle progression, albeit with a decrease in stemness, thus contributing to chemosensitization via the inhibition of HIF1α/HIF2α-Sox2.

Down-Regulation of Asparagine Synthetase Induces Cell Cycle Arrest and Inhibits Cell Proliferation of Breast Cancer

2014 ◽  
Vol 84 (5) ◽  
pp. 578-584 ◽  
Author(s):  
Hongjian Yang ◽  
Xiangming He ◽  
Yabing Zheng ◽  
Weiliang Feng ◽  
Xianghou Xia ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Asparagine Synthetase ◽  
Down Regulation ◽  
Cycle Arrest
Sign in / Sign up

Export Citation Format

Share Document