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1.
Background
Genotoxic stress, such as by exposure to bromodeoxyuridine (BrdU) and cigarette smoke, induces premature cell senescence. Recent evidence indicates that cellular senescence of various types of cells is accelerated in COPD patients. However, whether the senescence of airway epithelial cells contributes to the development of airway diseases is unknown. The present study was designed to test the hypothesis that premature senescence of airway epithelial cells (Clara cells) impairs repair processes and exacerbates inflammation after airway injury.Methods
C57/BL6J mice were injected with the Clara-cell-specific toxicant naphthalene (NA) on days 0, 7, and 14, and each NA injection was followed by a daily dose of BrdU on each of the following 3 days, during which regenerating cells were allowed to incorporate BrdU into their DNA and to senesce. The p38 MAPK inhibitor SB202190 was injected 30 minutes before each BrdU dose. Mice were sacrificed at different times until day 28 and lungs of mice were obtained to investigate whether Clara cell senescence impairs airway epithelial regeneration and exacerbates airway inflammation. NCI-H441 cells were induced to senesce by exposure to BrdU or the telomerase inhibitor MST-312. Human lung tissue samples were obtained from COPD patients, asymptomatic smokers, and nonsmokers to investigate whether Clara cell senescence is accelerated in the airways of COPD patients, and if so, whether it is accompanied by p38 MAPK activation.Results
BrdU did not alter the intensity of the airway epithelial injury or inflammation after a single NA exposure. However, after repeated NA exposure, BrdU induced epithelial cell (Clara cell) senescence, as demonstrated by a DNA damage response, p21 overexpression, increased senescence-associated β-galactosidase activity, and growth arrest, which resulted in impaired epithelial regeneration. The epithelial senescence was accompanied by p38 MAPK-dependent airway inflammation. Senescent NCI-H441 cells impaired epithelial wound repair and secreted increased amounts of pro-inflammatory cytokines in a p38 MAPK-dependent manner. Clara cell senescence in COPD patients was accelerated and accompanied by p38 MAPK activation.Conclusions
Senescence of airway epithelial cells impairs repair processes and exacerbates p38 MAPK-dependent inflammation after airway injury, and it may contribute to the pathogenesis of COPD. 相似文献2.
Background
We have previously reported that glycerol acts as a chemical chaperone to restore the expression of WAF1 in some human cancer cell lines bearing mutant p53. Since the expression of WAF1 is up-regulated by activated wildtype p53, glycerol appears to restore wtp53 function. The aim of the present study is to examine the restoration of heat-induced p53-dependent apoptosis by glycerol in human glioblastoma cells (A-172) transfected with a vector carrying a mutant p53 gene (A-172/mp53 cells) or neo control vector (A-172/neo cells). 相似文献3.
Background
P53 is a key tumor suppressor protein. In response to DNA damage, p53 accumulates to high levels in differentiated cells and activates target genes that initiate cell cycle arrest and apoptosis. Since stem cells provide the proliferative cell pool within organisms, an efficient DNA damage response is crucial. 相似文献4.
Vasanthi Govindaraju Marie-Claire Michoud Pasquale Ferraro Janine Arkinson Katherine Safka Hector Valderrama-Carvajal James G Martin 《Respiratory research》2008,9(1):1-11
Background
Clara cells are the epithelial progenitor cell of the small airways, a location known to be important in many lung disorders. Although migration of alveolar type II and bronchiolar ciliated epithelial cells has been examined, the migratory response of Clara cells has received little attention.Methods
Using a modification of existing procedures for Clara cell isolation, we examined mouse Clara cells and a mouse Clara-like cell line (C22) for adhesion to and migration toward matrix substrate gradients, to establish the nature and integrin dependence of migration in Clara cells.Results
We observed that Clara cells adhere preferentially to fibronectin (Fn) and type I collagen (Col I) similar to previous reports. Migration of Clara cells can be directed by a fixed gradient of matrix substrates (haptotaxis). Migration of the C22 cell line was similar to the Clara cells so integrin dependence of migration was evaluated with this cell line. As determined by competition with an RGD containing-peptide, migration of C22 cells toward Fn and laminin (Lm) 511 (formerly laminin 10) was significantly RGD integrin dependent, but migration toward Col I was RGD integrin independent, suggesting that Clara cells utilize different receptors for these different matrices.Conclusion
Thus, Clara cells resemble alveolar type II and bronchiolar ciliated epithelial cells by showing integrin mediated pro-migratory changes to extracellular matrix components that are present in tissues after injury. 相似文献5.
William R Davidson Csaba Kari Qing Ren Borbala Daroczi Adam P Dicker Ulrich Rodeck 《BMC developmental biology》2010,10(1):102
Background
The p53 protein family coordinates stress responses of cells and organisms. Alternative promoter usage and/or splicing of p53 mRNA gives rise to at least nine mammalian p53 proteins with distinct N- and C-termini which are differentially expressed in normal and malignant cells. The human N-terminal p53 variants contain either the full-length (FL), or a truncated (ΔN/Δ40) or no transactivation domain (Δ133) altogether. The functional consequences of coexpression of the different p53 isoforms are poorly defined. Here we investigated functional aspects of the zebrafish ΔNp53 ortholog in the context of FLp53 and the zebrafish Δ133p53 ortholog (Δ113p53) coexpressed in the developing embryo. 相似文献6.
Napapat Amornwichet Takahiro Oike Atsushi Shibata Hideaki Ogiwara Naoto Tsuchiya Motohiro Yamauchi Yuka Saitoh Ryota Sekine Mayu Isono Yukari Yoshida Tatsuya Ohno Takashi Kohno Takashi Nakano 《PloS one》2014,9(12)
Background and Purpose
To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies.Materials and Methods
DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively) were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs) by immunostaining of phosphorylated H2AX (γH2AX), and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3.Results
The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation.Conclusions
Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment. 相似文献7.
Cadmium-induced apoptosis of primary epithelial lung cells: Involvement of Bax and p53, but not of oxidative stress 总被引:11,自引:0,他引:11
Lag M Westly S Lerstad T Bjørnsrud C Refsnes M Schwarze PE 《Cell biology and toxicology》2002,18(1):29-42
The lung is a target organ for cadmium (Cd) toxicity. Apoptosis induced by cadmium acetate (CdAc) was studied in alveolar
type 2 cells and Clara cells isolated from rat lung. Relatively low concentrations of CdAc (1–10 μmol/L) induced apoptosis
after exposure for 20 h. Type 2 cells were more sensitive than Clara cells to Cd-induced apoptosis and loss of cell viability.
On exposure to 10 μmol/L CdAc, the levels of the apoptosis-modulating proteins p53 and Bax were increased at 2 h and 5–12
h, respectively. The expression of p53 preceded the expression of Bax and the apoptotic process. The exposure to 10 μmol/L
CdAc did not significantly increase the formation of cellular reactive oxygen species (ROS). However, after exposure to a
high concentration of CdAc (100 μmol/L), a 30% increase of the ROS level was observed. No significant nitric oxide production
was measured following CdAc exposure. Catalase, superoxide dismutase, dimethyl sulfoxide, or tetramethylthiourea did not protect
against Cd-induced apoptosis. In conclusion, the results show that Clara cells and type 2 cells are sensitive to Cd-induced
apoptosis. Increased levels of p53 and Bax are suggested to be involved in the apoptosis. The apoptosis did not appear to
be mediated by oxidative pathways.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
Tingzhe Sun Chun Chen Yuanyuan Wu Shuai Zhang Jun Cui Pingping Shen 《BMC bioinformatics》2009,10(1):190
Background
The tumor suppressor p53 plays pivotal roles in tumorigenesis suppression. Although oscillations of p53 have been extensively studied, the mechanism of p53 pulses and their physiological roles in DNA damage response remain unclear. 相似文献9.
10.
Purpose of work
Mutation of the p53 gene is the most common genetic alteration in human cancers. Our study proposes to rationally design a p53 antisense oligonucleotide (ASO) repository, which contains a series of ASOs containing single nucleotide differences to discriminate between each mutant and wild type (WT) p53. 相似文献11.
Background
The p53 tumor suppressor protein is involved in a complicated regulatory network, mediating expression of ~1000 human genes. Recent studies have shown that many p53 in vivo binding sites (BSs) reside in transposable repeats. The relationship between these BSs and functional p53 response elements (REs) remains unknown, however. We sought to understand whether the p53 REs also reside in transposable elements and particularly in the most-abundant Alu repeats. 相似文献12.
13.
Shelly A Christman Byung-Whi Kong Megan M Landry Hyunggee Kim Douglas N Foster 《BMC cell biology》2006,7(1):1-12
Background
The present study was carried out to determine whether the p53 pathway played a role in the spontaneous immortalization of the SC-2 chicken embryo fibroblast (CEF) cell line that has been in continuous culture for over three years.Results
The SC-2 cell line emerged from an extended crisis period with a considerably slower growth rate than primary CEF cells. The phenotype of the SC-2 cells changed dramatically at about passage 80, appearing smaller than at earlier passages (e.g., passage 43) and possessing a small, compact morphology. This morphological change coincided with an increase in growth rate. Passage 43 SC-2 cells expressed undetectable levels of p53 mRNA, but by passage 95, the levels were elevated compared to primary passage 6 CEF cells and similar to levels in senescent CEF cells. However, the high level of p53 mRNA detected in passage 95 SC-2 cells did not correlate to functional protein activity. The expression levels of the p53-regulated p21WAF1 gene were significantly decreased in all SC-2 passages that were analyzed. Examination of the Rb pathway revealed that E2F-1 and p15INK4b expression fluctuated with increasing passages, with levels higher in passage 95 SC-2 cells compared to primary passage 6 CEF cells.Conclusion
The present study suggests that altered expression of genes involved in the p53 and Rb pathways, specifically, p53 and p21WAF1, may have contributed to the immortalization of the SC-2 CEF cell line. 相似文献14.
Yusmazura Zakaria Asmah Rahmat Azimahtol Hawariah Hawariah Lope Pihie Noor Rain Abdullah Peter J Houghton 《Cancer cell international》2009,9(1):16-21
Background
Eurycomanone is a cytotoxic compound found in Eurycoma longifolia Jack. Previous studies had noted the cytotoxic effect against various cancer cell lines. The aim of this study is to investigate the cytotoxicity against human hepato carcinoma cell in vitro and the mode of action. The cytotoxicity of eurycomanone was evaluated using MTT assay and the mode of cell death was detected by Hoechst 33258 nuclear staining and flow cytometry with Annexin-V/propidium iodide double staining. The protein expression Bax, Bcl-2, p53 and cytochrome C were studied by flow cytometry using a spesific antibody conjugated fluorescent dye to confirm the up-regulation of p53 and Bax in cancer cells. 相似文献15.
16.
Dan-Dan Li Ting Sun Xiao-Qi Wu Shu-Peng Chen Rong Deng Shan Jiang Gong-Kan Feng Jing-Xuan Pan Xiao-Shi Zhang Yi-Xin Zeng Xiao-Feng Zhu 《PloS one》2012,7(9)
Background
Topotecan produces DNA damage that induces autophagy in cancer cells. In this study, sensitising topotecan to colon cancer cells with different P53 status via modulation of autophagy was examined.Methodology/Principal Findings
The DNA damage induced by topotecan treatment resulted in cytoprotective autophagy in colon cancer cells with wild-type p53. However, in cells with mutant p53 or p53 knockout, treatment with topotecan induced autophagy-associated cell death. In wild-type p53 colon cancer cells, topotecan treatment activated p53, upregulated the expression of sestrin 2, induced the phosphorylation of the AMPKα subunit at Thr172, and inhibited the mTORC1 pathway. Furthermore, the inhibition of autophagy enhanced the anti-tumour effect of topotecan treatment in wild-type p53 colon cancer cells but alleviated the anti-tumour effect of topotecan treatment in p53 knockout cells in vivo.Conclusions/Significance
These results imply that the wild-type p53-dependent induction of cytoprotective autophagy is one of the cellular responses that determines the cellular sensitivity to the DNA-damaging drug topotecan. Therefore, our study provides a potential therapeutic strategy that utilises a combination of DNA-damaging agents and autophagy inhibitors for the treatment of colon cancer with wild-type p53. 相似文献17.
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Andrew N. Sharp Alexander E. P. Heazell Dora Baczyk Caroline E. Dunk Helen A. Lacey Carolyn J. P. Jones Jonathan E. Perkins John C. P. Kingdom Philip N. Baker Ian P. Crocker 《PloS one》2014,9(1)