scholarly journals Expression of COX2 and p53 in Rat Esophageal Cancer Induced by Reflux of Duodenal Contents

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Naoki Hashimoto
Keyword(s):  
Esophageal Cancer ◽  
Mucosal Injury ◽  
Duodenal Content ◽  
Nuclear Antigen ◽  
Cancer Tissue ◽  
Wild Type ◽  
Male Wistar Rats ◽  
Wild Type P53 ◽  
Proliferating Cell ◽  
Cox2 Expression

Aim. Reflux of duodenal contents can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. We examined the expression of COX2 and p53 in rat esophageal lesions induced by duodenal content reflux. Methods. Thirty 8-week-old male Wistar rats were exposed to duodenal content esophageal reflux. All animals underwent an esophagoduodenal anastomosis (EDA) with total gastrectomy in order to produce chronic esophagitis. Ten rats were the sham. Control. They were sacrificed at the 40th week. Their esophagi were examined for HE, COX2, p53, and proliferating cell nuclear antigen (PCNA). Results. After 40 weeks of reflux, dysplasia, squamous cell carcinoma (SCC), and adenocarcinoma (ADC) were found. PCNA labeling index was higher in dysplastic and cancer tissue than that in normal. Overexpression of COX2 was shown in ADC and SCC. Wild-type p53 accumulation was found in ADC, and not in SCC. Conclusion. Reflux of duodenal contents into the esophagus led to ADC and SCC in rats. COX2 may play an important role in esophageal cancer by duodenal content reflux. Our present results suggest an association between wild-type p53 accumulation and COX2 expression in ADC, with no such relation seen in SCC.

scholarly journals Wild-type human p53 transactivates the human proliferating cell nuclear antigen promoter.

1995 ◽  
Vol 15 (12) ◽  
pp. 6785-6793 ◽  
Author(s):  
C V Shivakumar ◽  
D R Brown ◽  
S Deb ◽  
S P Deb
Keyword(s):  
Binding Site ◽  
Proliferating Cell Nuclear Antigen ◽  
P53 Protein ◽  
Cellular Growth ◽  
Nuclear Antigen ◽  
Wild Type ◽  
P53 Response ◽  
Low Levels ◽  
Wild Type P53 ◽  
Proliferating Cell

The wild-type p53 protein is a transcriptional activator implicated in the control of cellular growth-related gene expression. Here, using a number of different cell lines and transient-transfection-transcription assays, we demonstrate that at low levels, wild-type p53 transactivates the human proliferating cell nuclear antigen (PCNA) promoter. When expressed at a similar level, the tumor-derived p53 mutants did not transactivate the PCNA promoter. We identified a p53-binding site on the human PCNA promoter with which p53 interacts sequence specifically. When placed on a heterologous synthetic promoter, the binding site functions as a wild-type p53 response element in either orientation. Deletion of the p53-binding site renders the PCNA promoter p53 nonresponsive, showing that wild-type p53 transactivates the PCNA promoter by binding to the site. At a higher concentration, wild-type p53 inhibits the PCNA promoter but p53 mutants activate. Transactivation by p53 mutants does not require the p53-binding site. These observations suggest that moderate elevation of the cellular wild-type p53 level induces PCNA production to help in DNA repair.

scholarly journals Characterization of the Proliferating Cell Nuclear Antigen of Leishmania donovani Clinical Isolates and Its Association with Antimony Resistance

2014 ◽  
Vol 58 (6) ◽  
pp. 2997-3007 ◽  
Author(s):  
Rati Tandon ◽  
Sharat Chandra ◽  
Rajendra Kumar Baharia ◽  
Sanchita Das ◽  
Pragya Misra ◽  
...  
Keyword(s):  
Clinical Isolate ◽  
Proliferating Cell Nuclear Antigen ◽  
Leishmania Donovani ◽  
Clinical Isolates ◽  
Resistant Isolate ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Content Type ◽  
Sensitive Isolate ◽  
Proliferating Cell

ABSTRACTPreviously, through a proteomic analysis, proliferating cell nuclear antigen (PCNA) was found to be overexpressed in the sodium antimony gluconate (SAG)-resistant clinical isolate compared to that in the SAG-sensitive clinical isolate ofLeishmania donovani. The present study was designed to explore the potential role of the PCNA protein in SAG resistance inL. donovani. For this purpose, the protein was cloned, overexpressed, purified, and modeled. Western blot (WB) and real-time PCR (RT-PCR) analyses confirmed that PCNA was overexpressed by ≥3-fold in the log phase, stationary phase, and peanut agglutinin isolated procyclic and metacyclic stages of the promastigote form and by ∼5-fold in the amastigote form of the SAG-resistant isolate compared to that in the SAG-sensitive isolate.L. donovaniPCNA (LdPCNA) was overexpressed as a green fluorescent protein (GFP) fusion protein in a SAG-sensitive clinical isolate ofL. donovani, and modulation of the sensitivities of the transfectants to pentavalent antimonial (SbV) and trivalent antimonial (SbIII) drugs was assessedin vitroagainst promastigotes and intracellular (J774A.1 cell line) amastigotes, respectively. Overexpression of LdPCNA in the SAG-sensitive isolate resulted in an increase in the 50% inhibitory concentrations (IC50) of SbV(from 41.2 ± 0.6 μg/ml to 66.5 ± 3.9 μg/ml) and SbIII(from 24.0 ± 0.3 μg/ml to 43.4 ± 1.8 μg/ml). Moreover, PCNA-overexpressing promastigote transfectants exhibited less DNA fragmentation compared to that of wild-type SAG-sensitive parasites upon SbIIItreatment. In addition, SAG-induced nitric oxide (NO) production was found to be significantly inhibited in the macrophages infected with the transfectants compared with that in wild-type SAG-sensitive parasites. Consequently, we infer that LdPCNA has a significant role in SAG resistance inL. donovaniclinical isolates, which warrants detailed investigations regarding its mechanism.

scholarly journals APIM-Mediated REV3L–PCNA Interaction Important for Error Free TLS Over UV-Induced DNA Lesions in Human Cells

2018 ◽  
Vol 20 (1) ◽  
pp. 100 ◽  
Author(s):  
Synnøve Ræder ◽  
Anala Nepal ◽  
Karine Bjørås ◽  
Mareike Seelinger ◽  
Rønnaug Kolve ◽  
...  
Keyword(s):  
Cell Lines ◽  
Proliferating Cell Nuclear Antigen ◽  
Dna Lesions ◽  
Full Length ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Replication Foci ◽  
Multiple Cell ◽  
Mutation Spectra ◽  
Proliferating Cell

Proliferating cell nuclear antigen (PCNA) is essential for the organization of DNA replication and the bypass of DNA lesions via translesion synthesis (TLS). TLS is mediated by specialized DNA polymerases, which all interact, directly or indirectly, with PCNA. How interactions between the TLS polymerases and PCNA affects TLS specificity and/or coordination is not fully understood. Here we show that the catalytic subunit of the essential mammalian TLS polymerase POLζ, REV3L, contains a functional AlkB homolog 2 PCNA interacting motif, APIM. APIM from REV3L fused to YFP, and full-length REV3L-YFP colocalizes with PCNA in replication foci. Colocalization of REV3L-YFP with PCNA is strongly reduced when an APIM-CFP construct is overexpressed. We also found that overexpression of full-length REV3L with mutated APIM leads to significantly altered mutation frequencies and mutation spectra, when compared to overexpression of full-length REV3L wild-type (WT) protein in multiple cell lines. Altogether, these data suggest that APIM is a functional PCNA-interacting motif in REV3L, and that the APIM-mediated PCNA interaction is important for the function and specificity of POLζ in TLS. Finally, a PCNA-targeting cell-penetrating peptide, containing APIM, reduced the mutation frequencies and changed the mutation spectra in several cell lines, suggesting that efficient TLS requires coordination mediated by interactions with PCNA.

Suppression of clonogenicity by mammalian Dnmt1 mediated by the PCNA-binding domain

2004 ◽  
Vol 82 (5) ◽  
pp. 589-596 ◽  
Author(s):  
Simeon Santourlidis ◽  
Fumihiro Kimura ◽  
Johannes Fischer ◽  
Wolfgang A Schulz
Keyword(s):  
Dna Methylation ◽  
Cell Lines ◽  
Dna Methyltransferase ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Acid Domain ◽  
Safe Mechanism ◽  
Fail Safe ◽  
Proliferating Cell ◽  
Amino Acid Domain

Overexpression of the major DNA methyltransferase Dnmt1 is cytotoxic and has been hypothesized to result in aberrant hypermethylation of genes required for cell survival. Indeed, overexpression of mouse or human Dnmt1 in murine and human cell lines decreased clonogenicity. By frame-shift and deletion constructs, this effect of mouse Dnmt1 was localized at the N-terminal 124 amino acid domain, which mediates interaction with proliferating cell nuclear antigen (PCNA). Mutation of the PCNA-binding site restored normal cloning efficiencies. Overexpression of Dnmt3A or Dnmt3B, which do not interact with PCNA, yielded weaker effects on clonogenicity. Following introduction of the toxic domain, no significant effects on apoptosis, replication, or overall DNA methylation were observed for up to 3 d. Suppression of clonogenicity by Dnmt1 was also observed in cell lines lacking wild-type p53, p21CIP1, or p16INK4A. Suppression of clonogenicity by Dnmt1 overexpression may act as a fail-safe mechanism against carcinogenicity of sustained Dnmt1 overexpression.Key words: carcinogenesis, DNA methyltransferase, DNA methylation, p53, PCNA.

Compensatory kidney growth in estrogen receptor-α null mice

2006 ◽  
Vol 290 (2) ◽  
pp. F319-F323 ◽  
Author(s):  
Jianhong Sun ◽  
William J. Langer ◽  
Kay Devish ◽  
Pascale H. Lane
Keyword(s):  
Estrogen Receptor ◽  
Kidney Diseases ◽  
Estrogen Receptor Α ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Kidney Weight ◽  
Kidney Growth ◽  
Igf I ◽  
Kidney Scarring ◽  
Proliferating Cell

Females are relatively protected in many progressive kidney diseases. Processes of kidney scarring and growth are intricately linked, and female kidneys are smaller than male kidneys. To better understand links between sex, growth, and the kidney, we examined compensatory kidney growth (CKG) after uninephrectomy (Unx) in wild-type and estrogen receptor-α null mice (ERKO). Mice (10 wk old) underwent Unx or sham procedure, with removal of all remaining kidney(s) 48 h later. Studies included kidney weight, renal content of protein, DNA, and insulin-like growth factor-I (IGF-I), serum IGF-I, mean glomerular area, and immunostaining for proliferating cell nuclear antigen (PCNA). Sham Unx produced no differences between left and right kidneys. Unx altered kidney weight, glomerular area, DNA content, IGF-I content, and PCNA regardless of sex or genotype. Females showed greater increases in kidney weight (26 vs. 19%) and glomerular area (73 vs. 51%) than males. Differences in kidney weight were restricted to wild-type females (32% increase); ERKO females showed an increase in kidney weight similar to males (19%). Genotype did not influence glomerular growth in this model. Both male and female mice exhibit hyperplastic growth 48 h after Unx, with more pronounced enlargement in females. Lack of estrogen receptor-α is associated with reduced CKG in females, probably via suppression of proliferation. ERKO mice did not demonstrate any alterations in compensatory glomerular enlargement. Kidney IGF-I content doubled after Unx, regardless of sex or genotype, implicating other mechanisms with regard to these findings.

scholarly journals Mutant DNA polymerase δ from thermosensitive Schizosaccharomyces pombe strains display reduced stimulation by proliferating cell nuclear antigen

1998 ◽  
Vol 335 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Mylène PERDERISET ◽  
Giovanni MAGA ◽  
Karine PIARD ◽  
Stefania FRANCESCONI ◽  
Isabelle TRATNER ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Dna Polymerase ◽  
Proliferating Cell Nuclear Antigen ◽  
Catalytic Subunit ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Low Levels ◽  
Proliferating Cell ◽  
Stimulation Of

We have isolated and characterized DNA polymerase δ (pol δ) from two thermosensitive Schizosaccharomyces pombe strains, polδts1 and polδts3, mutated in two different evolutionarily conserved domains of the catalytic subunit. At the restrictive temperature of 37 °C polδts1 and polδts3 mutant strains arrest growth in the S phase of the cell cycle. We show that at low levels of primer ends, in vitro stimulation by proliferating cell nuclear antigen (PCNA) of mutant enzymes is lower than stimulation of wild-type pol δ. Affinity for primer (3´-OH) ends and processivity of mutant enzymes do not appear different from wild-type pol δ. In contrast, Vmax values are lower than the wild-type value. The major in vitro defect appears to be decreased stimulation of mutant enzymes by PCNA, resulting in reduced velocity of DNA synthesis. In addition, ts1 pol δ is not stimulated by low PCNA concentration at 37 °C, although low concentrations stimulate activity at 25 °C, suggesting that this thermolability at low levels of primer ends could be its critical defect in vivo. Thus, both ts1 and ts3 pol δ mutations are located in regions of the catalytic subunit that seem necessary, directly or indirectly, for its efficient interaction with PCNA.

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