Expression of suppressor genes 53 and bcl-2 as well as of protein p21 (partly induced by p53 gene) was analyzed in a group of 77 resection specimens and bronchial excision of lung carcinomas (of all basic histological types--squamous cell, neuroendocrine, adenocarcinoma, undifferentiated). Simultaneously the relation of tumor immunophenotype and level of differentiation, cell death and 2-year-survival of patients was evaluated. Gene p53 showed non-only an expected strong expression in squamous cell carcinomas but especially in adenocarcinomas, which were newly characterized by exceptional hyper-expression of p53 in lowly differentiated variants. Expression level of protein p21 and gene p53 was parallel only in adenocarcinomas and undifferentiated carcinomas but discordant in squamous cell and neuroendocrine carcinomas. Positivity of p21 slightly prevailed in well-differentiated variants of the histological types but an exceptional positivity was found even in all the undifferentiated carcinomas. Gene bcl-2 revealed a paradox of strong expression in lowly differentiated neuroendocrine and undifferentiated carcinomas. The level of bcl-2 expression in squamous cell carcinomas was found higher than in references. Among tumors with cell death there was an inverted relation of bcl-2 and p53 expression (high/low) in neuroendocrine carcinomas but both of them were mostly negative in squamous cell carcinomas. A more frequent 2-year-survival of squamous cell carcinomas was verified for bcl-2 positive tumors and newly for p53 positive squamous cell carcinomas. Evaluation of the expression of p53, p21 and bcl-2 in lung carcinomas is so equivocal that its prognostic usage was found to be only complementary to the direct immunohistochemical investigation of the growth activities.

• MeSH
• imunohistochemie MeSH
• lidé MeSH
• nádorové biomarkery analýza   MeSH
• nádorový supresorový protein p53 analýza   MeSH
• nádory plic diagnóza   genetika   MeSH
• prognóza MeSH
• protoonkogenní proteiny c-bcl-2 analýza   MeSH
• protoonkogenní proteiny p21(ras) analýza   MeSH
• retrospektivní studie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• HRAS protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• nádorový supresorový protein p53 MeSH
• protoonkogenní proteiny c-bcl-2 MeSH
• protoonkogenní proteiny p21(ras) MeSH

AIM: To examine by means of immunohistochemistry the expression of the tumor suppressing gene p53 and gene p21 in cells of malignant melanoma of the uvea from formalin-paraffin material from patients, who were during the period 2000 - 2006 surgically treated due to malignant melanoma of the uvea at the Department of Ophthalmology in the University Hospital in Brno (Brunn), Czech Republic, E.U., and to correlate the results of the immunohistochemical detection with clinical signs of the tumor of each patient. METHODS: Twenty-nine malignant melanomas of the uvea were examined by means of monoclonal antibody DO-1 (Novocastra company) and all 29 samples of malignant melanoma of the uvea were immunohistochemically examined for the p21 gene expression by means of the monoclonal antibody SX 118 (DAKO company). We evaluated the percentage of positive nuclei and the intensity of the staining in immunohistochemically detected p53 and p21 genes expression. RESULTS: Results suitable for evaluation we obtained in 28 samples of malignant melanomas, one sample was not suitable for evaluation due to extremely high presence of melanin pigment. In 3 patients, weak nuclear p53 gene expression was detected in 5-15% of cells, in 1 patient, the very weak intensity of staining in 5-15% of cells was found. In three patients, in 5-15% of cells, weak expression of p21 gene, and in one patient, very weak expression of p21 gene in 5-15% of cells (in all 4 cases, the p53 expression was established) were found. In one of those 4 patients with p53 gene expression it was the malignant melanoma of the iris, in one of them it was malignant melanoma of the ciliary body, and in 2 of them it was malignant melanoma of the choroid. CONCLUSION: The expression of the p53 gene and the expression of the gene p21 were established in 4 out of 28 patients (14.3%). From the above-mentioned results we can assume that stabilizing mutations of p53 gene are rare in the melanoma of the uvea. The proved expression p53 in 4 patients is probably result of the expression of the standard (wild-type) p53 gene, especially according to the ability to induce the expression of p21 gene. In our group, there were not proved marked nuclear accumulation of p53, which would suggest the presence of p53 gene mutation.

• MeSH
• geny p53 * MeSH
• imunohistochemie MeSH
• inhibitor p21 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• lidé MeSH
• melanom genetika   metabolismus   MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• nádory uvey genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• CDKN1A protein, human MeSH Prohlížeč
• inhibitor p21 cyklin-dependentní kinasy MeSH
• nádorový supresorový protein p53 MeSH

P21-activated kinases (PAK) regulate processes associated with cytoskeleton dynamics. PAK expression in leukemia cells was measured on protein and mRNA levels. In functional assays, we analyzed the effect of PAK inhibitors IPA-3 and FRAX597 on cell adhesivity and viability. PAK2 was dominant in cell lines, whereas primary cells also expressed comparable amount of PAK1 transcription isoforms: PAK1-full and PAK1Δ15. PAK1Δ15 and PAK2 levels correlated with surface density of integrins β1 and αVβ3. PAK1-full, but not PAK2, was present in membrane protrusions. IPA-3, which prevents PAK activation, induced cell contraction in semi-adherent HEL cells only. FRAX597, which inhibits PAK kinase activity, increased cell-surface contact area in all leukemia cells. Both inhibitors reduced the stability of cell attachment and induced cell death.

• Klíčová slova
• AML, ECIS, IRM, PAK, acute myeloid leukemia, cell adhesion,
• MeSH
• buněčná adheze MeSH
• buněčné linie MeSH
• fibronektiny genetika   MeSH
• leukemie * genetika   MeSH
• lidé MeSH
• p21 aktivované kinasy * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibronektiny MeSH
• p21 aktivované kinasy * MeSH

The radial position of a gene within its chromosome territory (CT) in the interphase nucleus is thought to depend on the transcriptional activity of the gene and on transcriptional activity, gene density, and conformation of the chromosomal surrounding. In this study we analyzed the position of the cell cycle regulator gene p21 within the CT of human chromosome 6 (HSA6) upon transcriptional activation. Whereas the majority of active p21 genes is located in the interior of the CT of HSA6, induction of p21 transcription correlates with increased variation of gene localization within the CT and with a higher percentage of p21 genes located at the periphery of the CT. Additionally it demonstrates once more that transcription can take place throughout CTs. Comparison of the p21 locus with two non-coding regions on HSA6 showed that both non-coding sequences are located more frequently in the interior of the CT than p21 genes although they are situated in chromosomal neighborhoods with widely differing gene density and regional transcriptional activity. Thus our data support models describing an influence of the transcriptional activity of a gene on the localization within its CT. However, our data also indicate that additional factors such as chromatin remodeling are implicated in the positioning of genes within the respective chromosome territory.

• MeSH
• aktivace transkripce genetika   fyziologie   MeSH
• chromozomy metabolismus   MeSH
• hybridizace in situ fluorescenční MeSH
• inhibitor p21 cyklin-dependentní kinasy genetika   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• inhibitor p21 cyklin-dependentní kinasy MeSH

p21/ WAF1/ Cip1 (p21), a cyclin-dependent kinase inhibitor, may act as an antioncogene, but may also behave as a tumor promoting factor by inhibiting apoptosis. p21 is also a transcriptional regulator, exerting this activity independently of cyclin-dependent kinases. Increased p21 protein levels were found in a subset of melanomas. However, the mechanism(s) contributing to the tolerance of high p21 levels in melanoma cells remains unexplained. Here, we show that the p21 protein positively regulates the promoter of microphthalmia-associated transcription factor (MITF), a transcription factor which plays a central role in the expression of melanocyte-specific genes, lineage determination, and survival of melanoma cells. p21 activated the MITF promoter-reporter, occupied the promoter in vivo and cooperated with cAMP response element binding protein (CREB) in promoter activation. In addition, p21 knockdown by shRNA resulted in a decrease of MITF protein and promoter activity, and p21 protein levels correlated with MITF mRNA in most cell lines tested. As the p21 gene is a known transcriptional target of MITF, the reciprocal stimulation of transcription may constitute a positive-feedback loop reinforcing MITF expression in melanoma cells. Our results might help explain the tolerance of increased p21 levels found in some melanomas.

• MeSH
• inhibitor p21 cyklin-dependentní kinasy metabolismus   MeSH
• lidé MeSH
• melanom genetika   metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese u nádorů * MeSH
• transkripční faktor spojený s mikroftalmií genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• inhibitor p21 cyklin-dependentní kinasy MeSH
• messenger RNA MeSH
• MITF protein, human MeSH Prohlížeč
• transkripční faktor spojený s mikroftalmií MeSH

The cyclin-dependent kinase inhibitor p21(WAF1/CIP1) (p21) is a cell-cycle checkpoint effector and inducer of senescence, regulated by p53. Yet, evidence suggests that p21 could also be oncogenic, through a mechanism that has so far remained obscure. We report that a subset of atypical cancerous cells strongly expressing p21 showed proliferation features. This occurred predominantly in p53-mutant human cancers, suggesting p53-independent upregulation of p21 selectively in more aggressive tumour cells. Multifaceted phenotypic and genomic analyses of p21-inducible, p53-null, cancerous and near-normal cellular models showed that after an initial senescence-like phase, a subpopulation of p21-expressing proliferating cells emerged, featuring increased genomic instability, aggressiveness and chemoresistance. Mechanistically, sustained p21 accumulation inhibited mainly the CRL4-CDT2 ubiquitin ligase, leading to deregulated origin licensing and replication stress. Collectively, our data reveal the tumour-promoting ability of p21 through deregulation of DNA replication licensing machinery-an unorthodox role to be considered in cancer treatment, since p21 responds to various stimuli including some chemotherapy drugs.

• MeSH
• cykliny genetika   metabolismus   MeSH
• inhibitor p21 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• nádory genetika   MeSH
• nestabilita genomu genetika   MeSH
• replikace DNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cykliny MeSH
• inhibitor p21 cyklin-dependentní kinasy MeSH
• nádorový supresorový protein p53 MeSH
• TP53 protein, human MeSH Prohlížeč

The Wee1 inhibitor MK1775 (AZD1775) is currently being tested in clinical trials for cancer treatment. Here, we show that the p53 target and CDK inhibitor p21 protects against MK1775-induced DNA damage during S-phase. Cancer and normal cells deficient for p21 (HCT116 p21-/-, RPE p21-/-, and U2OS transfected with p21 siRNA) showed higher induction of the DNA damage marker γH2AX in S-phase in response to MK1775 compared to the respective parental cells. Furthermore, upon MK1775 treatment the levels of phospho-DNA PKcs S2056 and phospho-RPA S4/S8 were higher in the p21 deficient cells, consistent with increased DNA breakage. Cell cycle analysis revealed that these effects were due to an S-phase function of p21, but MK1775-induced S-phase CDK activity was not altered as measured by CDK-dependent phosphorylations. In the p21 deficient cancer cells MK1775-induced cell death was also increased. Moreover, p21 deficiency sensitized to combined treatment of MK1775 and the CHK1-inhibitor AZD6772, and to the combination of MK1775 with ionizing radiation. These results show that p21 protects cancer cells against Wee1 inhibition and suggest that S-phase functions of p21 contribute to mediate such protection. As p21 can be epigenetically downregulated in human cancer, we propose that p21 levels may be considered during future applications of Wee1 inhibitors.

• Klíčová slova
• CDK activity, DNA damage, Wee1 kinase, cancer treatment, checkpoint kinase inhibition, p21 (Cip1/Waf1),
• MeSH
• antitumorózní látky farmakologie   terapeutické užití   MeSH
• checkpoint kinasa 1 antagonisté a inhibitory   MeSH
• cyklin-dependentní kinasy antagonisté a inhibitory   metabolismus   MeSH
• fosforylace účinky léků   MeSH
• HCT116 buňky MeSH
• inhibitor p21 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• kontrolní body fáze S buněčného cyklu účinky léků   MeSH
• lidé MeSH
• malá interferující RNA genetika   MeSH
• nádory farmakoterapie   metabolismus   MeSH
• poškození DNA účinky léků   genetika   MeSH
• proteiny buněčného cyklu antagonisté a inhibitory   MeSH
• pyrazoly farmakologie   terapeutické užití   MeSH
• pyrimidinony farmakologie   terapeutické užití   MeSH
• transfekce MeSH
• tyrosinkinasy antagonisté a inhibitory   MeSH
• viabilita buněk účinky léků   genetika   účinky záření   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adavosertib MeSH Prohlížeč
• antitumorózní látky MeSH
• CDKN1A protein, human MeSH Prohlížeč
• checkpoint kinasa 1 MeSH
• CHEK1 protein, human MeSH Prohlížeč
• cyklin-dependentní kinasy MeSH
• inhibitor p21 cyklin-dependentní kinasy MeSH
• malá interferující RNA MeSH
• proteiny buněčného cyklu MeSH
• pyrazoly MeSH
• pyrimidinony MeSH
• tyrosinkinasy MeSH
• WEE1 protein, human MeSH Prohlížeč

We analyzed the effect of exposure to carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in ambient air on the plasma levels of p53 and p21(WAF1) proteins among city policemen, bus drivers and controls in three European cities: Prague (Czech Republic), Kosice (Slovakia) and Sofia (Bulgaria). p53 and p21(WAF1) proteins are key regulators of the cell cycle and are accepted as universal markers of genotoxic stress and DNA damage. In total 204 exposed subjects (100 smokers, 104 nonsmokers) and 152 controls (54 smokers, 98 nonsmokers) were analyzed. Personal exposure to c-PAHs was evaluated using personal samplers during the working shift. The levels of p53 and p21(WAF1) proteins were assessed by ELISA assay. There were no differences between the levels of either protein between exposed and controls, or smokers and nonsmokers, in any city. However, we observed significant differences in p53 plasma levels in all subjects regardless of the exposure status between the individual cities (median values: 5, 31, 234pg/ml, p<0.001, for Prague, Kosice and Sofia, respectively). The levels correspond to the differences in exposure levels to c-PAHs and benzo[a]pyrene (B[a]P) in the individual cities. A multiple linear regression analysis confirmed that c-PAHs exposure is a variable significantly affecting levels of both proteins in all locations. When all subjects were divided into the group exposed to below-median levels of c-PAHs and the group exposed to above-median levels of c-PAHs we found significantly higher p53, as well as p21(WAF1) levels in the above-median exposure group (p53, 167pg/ml versus 25pg/ml, p<0.001; p21(WAF1), 2690pg/ml versus 2600pg/ml, p<0.05). Among all subjects p53 plasma levels were positively correlated with p21(WAF1) levels, exposure to B[a]P, c-PAHs and levels of total DNA adducts; for p21(WAF1) levels we observed the positive correlation with cotinine, c-PAHs exposure, total and B[a]P-like DNA adduct levels. In conclusion our results suggest that p53 and p21(WAF1) proteins plasma levels may be useful biomarkers of c-PAHs environmental exposure.

• MeSH
• adukty DNA analýza   MeSH
• benzopyren toxicita   MeSH
• dospělí MeSH
• inhibitor p21 cyklin-dependentní kinasy krev   MeSH
• karcinogeny životního prostředí toxicita   MeSH
• kotinin krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorový supresorový protein p53 krev   MeSH
• policie MeSH
• polycyklické aromatické uhlovodíky toxicita   MeSH
• senioři MeSH
• znečištění ovzduší * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• benzopyren MeSH
• CDKN1A protein, human MeSH Prohlížeč
• inhibitor p21 cyklin-dependentní kinasy MeSH
• karcinogeny životního prostředí MeSH
• kotinin MeSH
• nádorový supresorový protein p53 MeSH
• polycyklické aromatické uhlovodíky MeSH

To examine a possible involvement of p21 protein, an inhibitor of cyclin-dependent kinases (CDKs), in the transition from hyperplastic to hypertrophic growth of rat ventricular myocytes during the first postnatal week, we analysed day-by-day changes in the number of p21 positive cells using specific antibodies against this protein. Paraffin-embedded sections of the left ventricular myocardium were examined by means of immunoperoxidase technique and hematoxylin-eosin counterstaining. While during the first three postnatal days, the positive reaction for p21 was detected only in a small fraction of myocytes (12-20%), a sudden increase in positivity occurred on day 4 (54%) and continued till day 6 when the fraction of cells expressing p21 reached 87%. Our results show that the induction of CDK inhibitor p21 in rat ventricular myocytes is developmentally regulated. Moreover, the fact that the sudden increase in p21 positivity occurred at the same stage when the myocyte proliferation rapidly ceases, suggests that this protein is likely to be involved in mediating this key event of cardiac development.

• MeSH
• buněčné dělení * MeSH
• cyklin-dependentní kinasy antagonisté a inhibitory   MeSH
• cykliny biosyntéza   MeSH
• inhibitor p21 cyklin-dependentní kinasy MeSH
• inhibitory enzymů * MeSH
• krysa rodu Rattus MeSH
• myokard cytologie   metabolismus   MeSH
• novorozená zvířata * MeSH
• potkani Wistar MeSH
• stárnutí MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Cdkn1a protein, rat MeSH Prohlížeč
• cyklin-dependentní kinasy MeSH
• cykliny MeSH
• inhibitor p21 cyklin-dependentní kinasy MeSH
• inhibitory enzymů * MeSH

Studies of human embryonic stem cells (hESCs) commonly describe the nonfunctional p53-p21 axis of the G1/S checkpoint pathway with subsequent relevance for cell cycle regulation and the DNA damage response (DDR). Importantly, p21 mRNA is clearly present and upregulated after the DDR in hESCs, but p21 protein is not detectable. In this article, we provide evidence that expression of p21 protein is directly regulated by the microRNA (miRNA) pathway under standard culture conditions and after DNA damage. The DDR in hESCs leads to upregulation of tens of miRNAs, including hESC-specific miRNAs such as those of the miR-302 family, miR-371-372 family, or C19MC miRNA cluster. Most importantly, we show that the hESC-enriched miRNA family miR-302 (miR-302a, miR-302b, miR-302c, and miR-302d) directly contributes to regulation of p21 expression in hESCs and, thus, demonstrate a novel function for miR-302s in hESCS. The described mechanism elucidates the role of miRNAs in regulation of important molecular pathway governing the G1/S transition checkpoint before as well as after DNA damage.

• MeSH
• buněčná diferenciace genetika   fyziologie   MeSH
• buněčné linie MeSH
• embryonální kmenové buňky metabolismus   MeSH
• inhibitor p21 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• koncové značení zlomů DNA in situ MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• poškození DNA genetika   MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• inhibitor p21 cyklin-dependentní kinasy MeSH
• mikro RNA MeSH
• nádorový supresorový protein p53 MeSH