Oncogene-induced replication stress has been recognized as a major cause of genome instability in cancer cells. Increased expression of cyclin E1 caused by amplification of the CCNE1 gene is a common cause of replication stress in various cancers. Protein phosphatase magnesium-dependent 1 delta (PPM1D) is a negative regulator of p53 and has been implicated in termination of the cell cycle checkpoint. Amplification of the PPM1D gene or frameshift mutations in its final exon promote tumorigenesis. Here, we show that PPM1D activity further increases the replication stress caused by overexpression of cyclin E1. In particular, we demonstrate that cells expressing a truncated mutant of PPM1D progress faster from G1 to S phase and fail to complete licensing of the replication origins. In addition, we show that transcription-replication collisions and replication fork slowing caused by CCNE1 overexpression are exaggerated in cells expressing the truncated PPM1D. Finally, replication speed and accumulation of focal DNA copy number alterations caused by induction of CCNE1 expression was rescued by pharmacological inhibition of PPM1D. We propose that increased activity of PPM1D suppresses the checkpoint function of p53 and thus promotes genome instability in cells expressing the CCNE1 oncogene.

• MeSH
• cyklin E genetika   metabolismus   MeSH
• lidé MeSH
• nádorový supresorový protein p53 * genetika   metabolismus   MeSH
• nádory * MeSH
• nestabilita genomu MeSH
• proteinfosfatasa 2C genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

From four molecules, inspired by the structural features of fascaplysin, with an interesting potential to inhibit cyclin-dependent kinases (CDKs), we designed a new series of tri-heterocyclic derivatives based on 1H-pyrrolo[2,3-b]pyridine (7-azaindole) and triazole heterocycles. Using a Huisgen type [3 + 2] cycloaddition as the convergent key step, 24 derivatives were synthesized and their biological activities were evaluated. Comparative molecular field analysis (CoMFA), based on three-dimensional quantitative structure-activity relationship (3D-QSAR) studies, was conducted on a series of 30 compounds from the literature with high to low known inhibitory activity towards CDK2/cyclin E and was validated by a test set of 5 compounds giving satisfactory predictive r(2) value of 0.92. Remarkably, it also gave a good prediction of pIC50 for our tri-heterocyclic series which reinforce the validation of this model for the pIC50 prediction of external set compounds. The most promising compound, 43, showed a micro-molar range inhibitory activity against CDK2/cyclin E and also an antiproliferative and proapoptotic activity against a panel of cancer cell lines.

• MeSH
• cyklin E antagonisté a inhibitory   metabolismus   MeSH
• cyklin-dependentní kinasa 2 antagonisté a inhibitory   metabolismus   MeSH
• heterocyklické sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• indoly chemická syntéza   chemie   farmakologie   MeSH
• inhibitory enzymů chemická syntéza   chemie   farmakologie   MeSH
• kvantitativní vztahy mezi strukturou a aktivitou MeSH
• lidé MeSH
• molekulární modely * MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• proliferace buněk účinky léků   MeSH
• protinádorové látky chemická syntéza   chemie   farmakologie   MeSH
• screeningové testy protinádorových léčiv MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Current knowledge about pathogenesis of vulvar lesions including genital warts, precancerous lesions, vulvar cancer has led to an update of classification of precancerous lesions. The aim is to find optimal algorithms for each entity and to enhance our knowledge on predictive factors which can be used for clinical praxis. In this project we plan to correlate HPV profiles of lesions with histopathological characteristics especially morphological diagnostic sings of HPV positive and HPV negative lesions. HPV profiles will be correlated with expression of immunohistochemical markers, mainly p161NK4a(p16). Another predictive factors will be assessed including minichromosome maintenance protein 2 (MCM2), DNA topoisomerase II Alfa (TOP IIA), cycline E and ProExC (mixture of antibodies against MCM2 and TOP IIA). When combined the predictive factors could improve sensitivity and specificity of histopathological examination. Diagnostic and therapeutic algorithms should be clinical outcome of the project.

Současné znalosti o patogenezi kondylomat, prekanceróz a karcinomů vulvy vedly k změně klasifikace prekanceróz. Projekt si klade za cíle vytvořit diagnosticko – terapeutické algoritmy pro jednotlivé jednotky, rozšířit znalosti o prediktivních faktorech. Projekt plánuje korelovat HPV profily lézí s histologickou charakteristikou, s důrazem na rozlišení morfologických znaků HPV pozitivních a HPV negativních. HPV profily budou korelovány s expresí imunohistochemických markerů, především pl6INK4a (p16). Dále bude vyhodnocen diagnostický přínos protilátek proti minichromosome maintenance protein 2 (MCM2), DNA topoisomeráze II alfa (TOP IIA), cyclinu E a ProExC (směs protilátek proti MCM2 a TOP IIA). Cílem je dosáhnout zvýšení specificity a senzitivity histopatologického vyšetření a tím nově optimalizovat diagnosticko–terapeutické algoritmy.

• MeSH
• algoritmy MeSH
• cyklin E analýza   MeSH
• imunohistochemie metody   využití   MeSH
• incidence MeSH
• inhibitory topoisomerasy II analýza   MeSH
• karcinom diagnóza   terapie   MeSH
• kondylomata akuminata diagnóza   terapie   MeSH
• kvalita života MeSH
• lymfadenektomie MeSH
• MCM proteiny analýza   antagonisté a inhibitory   MeSH
• mortalita MeSH
• nádorové biomarkery analýza   MeSH
• nádory vulvy diagnóza   terapie   MeSH
• prediktivní hodnota testů MeSH
• prekancerózy diagnóza   terapie   MeSH
• vakcinace MeSH
• ženy MeSH

• Konspekt
• Gynekologie. Porodnictví
• NLK Obory
• gynekologie a porodnictví
• onkologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

UNLABELLED: Molecular mechanisms of lapatinib resistance in breast cancer are not well understood. The aim of this study was to correlate expression of selected proteins involved in ErbB family signaling pathways with clinical efficacy of lapatinib. Study group included 270 HER2-positive advanced breast cancer patients treated with lapatinib and capecitabine. Immunohistochemical expression of phosphorylated adenosine monophosphate-activated protein (p-AMPK), mitogen-activated protein kinase (p-MAPK), phospho (p)-p70S6K, cyclin E, phosphatase and tensin homolog were analyzed in primary breast cancer samples. The best discriminative value for progression-free survival (PFS) was established for each biomarker and subjected to multivariate analysis. At least one biomarker was determined in 199 patients. Expression of p-p70S6K was independently associated with longer (HR 0.45; 95% CI: 0.25-0.81; p = 0.009), and cyclin E with shorter PFS (HR 1.83; 95% CI: 1.06-3.14; p = 0.029). Expression of p-MAPK (HR 1.61; 95% CI 1.13-2.29; p = 0.009) and cyclin E (HR 2.99; 95% CI: 1.29-6.94; p = 0.011) was correlated with shorter, and expression of estrogen receptor (HR 0.65; 95% CI 0.43-0.98; p = 0.041) with longer overall survival. Expression of p-AMPK negatively impacted response to treatment (HR 3.31; 95% CI 1.48-7.44; p = 0.004) and disease control (HR 3.07; 95% CI 1.25-7.58; p = 0.015). IN CONCLUSION: the efficacy of lapatinib seems to be associated with the activity of downstream signaling pathways - AMPK/mTOR and Ras/Raf/MAPK. Further research is warranted to assess the clinical utility of these data and to determine a potential role of combining lapatinib with MAPK pathway inhibitors.

• MeSH
• chinazoliny terapeutické užití   MeSH
• cyklin E metabolismus   MeSH
• dospělí MeSH
• fosforylace účinky léků   MeSH
• hodnocení výsledků zdravotní péče metody   statistika a číselné údaje   MeSH
• imunohistochemie metody   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• Kaplanův-Meierův odhad MeSH
• kinasy ribozomálního proteinu S6, 70-kDa metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• mladý dospělý MeSH
• nádory prsu farmakoterapie   metabolismus   patologie   MeSH
• prediktivní hodnota testů MeSH
• prognóza MeSH
• proporcionální rizikové modely MeSH
• receptor erbB-2 antagonisté a inhibitory   metabolismus   MeSH
• receptory pro estrogeny metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Proper control of cyclin-dependent kinases ensures coordinated cell cycle progression and guards against tumorigenesis. A new study identifies the PARK2 E3 ubiquitin ligase as an important coordinator of G1/S-phase cyclin turnover and explains how mutations targeting this key cell cycle regulatory node contribute to a range of cancers.

• MeSH
• buněčný cyklus * MeSH
• cyklin D1 metabolismus   MeSH
• cyklin E metabolismus   MeSH
• cyklin-dependentní kinasa 4 metabolismus   MeSH
• lidé MeSH
• onkogenní proteiny metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• ubikvitinligasy genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• komentáře MeSH

MiR-34a acts as a candidate tumour suppressor gene, and its expression is reduced in several cancer types. We aimed to study miR-34a expression in breast cancer and its correlation with tumour characteristics and clinical outcome, and regulatory links with other genes. We analysed miR-34a expression in 1,172 breast tumours on TMAs. 25% of the tumours showed high, 43% medium and 32% low expression of miR-34a. High miR-34a expression associated with poor prognostic factors for breast cancer: positive nodal status (p = 0.006), high tumour grade (p<0.0001), ER-negativity (p = 0.0002), HER2-positivity (p = 0.0002), high proliferation rate (p<0.0001), p53-positivity (p<0.0001), high cyclin E (p<0.0001) and H2AX (p<0.0001). However, multivariate analysis adjusting for conventional prognostic factors indicated that high miR-34a expression in fact associated with a lower risk of recurrence or death from breast cancer (HR = 0.63, 95% CI = 0.41-0.96, p = 0.031). Gene expression analysis by differential miR-34a expression revealed an expression signature with an effect on both the 5-year and 10-year survival of the patients (p<0.001). Functional genomic analysis highlighted a novel regulatory role of the transcription factor MAZ, apart from the known control by p53, on the expression of miR-34a and a number of miR-34a targets. Our findings suggest that while miR-34a expression activation is a marker of aggressive breast tumour phenotype it exerts an independent effect for a lower risk of recurrence or death from breast cancer. We also present an expression signature of 190 genes associated with miR-34a expression. Our analysis for regulatory loops suggest that MAZ and p53 transcription factors co-operate in modulating miR-34a, as well as miR-34a targets involved in several cellular pathways. Taken together, these results suggest that the network of genes co-regulated with and targeted by miR-34a form a group of down-stream effectors that maybe of use in predicting clinical outcome, and that highlight novel regulatory mechanisms in breast cancer.

• MeSH
• cyklin E genetika   MeSH
• DNA vazebné proteiny genetika   MeSH
• duktální karcinom prsu * genetika   mortalita   sekundární   MeSH
• histony genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• lobulární karcinom * genetika   mortalita   sekundární   MeSH
• mikro RNA * genetika   MeSH
• nádory prsu * genetika   mortalita   patologie   MeSH
• staging nádorů MeSH
• stanovení celkové genové exprese MeSH
• stupeň nádoru MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH

BACKGROUND/AIM: 9-[2-(phosphonomethoxy)ethyl] guanine (PMEG) is a guanine acyclic nucleotide analog whose targeted prodrugs are being investigated for chemotherapy of lymphomas. Its antiproliferative effects have been attributed to cell cycle arrest and induction of apoptosis, however, the underlying mechanisms remain poorly understood. The objective of this study was to determine the requirements for caspase and CD95/Fas activation in PMEG-induced apoptosis. Additionally, the influence of PMEG on cell cycle regulatory proteins was explored. MATERIALS AND METHODS: CCRF-CEM cells were exposed to PMEG with/without caspase inhibitor or anti-Fas blocking antibody and assayed for phosphatidyl serine externalization, mitochondrial depolarization and the cleavage of procaspase 3 and the nuclear protein poly (ADP-ribose) polymerase (PARP). RESULTS: Despite an observed increase of caspase 3, 8 and 9 proteolytic activity, neither pretreatment of the cells with cell-permeable caspase inhibitors nor blocking the death receptor with anti-Fas antibody did prevent apoptosis induced by PMEG. CONCLUSION: PMEG-induced apoptosis is caspase- and CD95/Fas-independent.

• MeSH
• aktivace enzymů MeSH
• antigeny CD95 metabolismus   MeSH
• apoptóza účinky léků   fyziologie   MeSH
• buněčný cyklus účinky léků   fyziologie   MeSH
• cyklin E biosyntéza   genetika   MeSH
• cyklin-dependentní kinasy biosyntéza   metabolismus   MeSH
• guanin analogy a deriváty   farmakologie   MeSH
• inhibiční proteiny cyklin-dependentních kinas biosyntéza   metabolismus   MeSH
• kaspasy metabolismus   MeSH
• lidé MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondrie účinky léků   fyziologie   MeSH
• nádorové buněčné linie MeSH
• onkogenní proteiny biosyntéza   genetika   MeSH
• organofosforové sloučeniny farmakologie   MeSH
• S fáze účinky léků   MeSH
• signální transdukce MeSH
• T-lymfocyty cytologie   účinky léků   enzymologie   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: This article is to study the role of G(1)/S regulators in differentiation of pluripotent embryonic cells. MATERIALS AND METHODS: We established a P19 embryonal carcinoma cell-based experimental system, which profits from two similar differentiation protocols producing endodermal or neuroectodermal lineages. The levels, mutual interactions, activities, and localization of G(1)/S regulators were analysed with respect to growth and differentiation parameters of the cells. RESULTS AND CONCLUSIONS: We demonstrate that proliferation parameters of differentiating cells correlate with the activity and structure of cyclin A/E-CDK2 but not of cyclin D-CDK4/6-p27 complexes. In an exponentially growing P19 cell population, the cyclin D1-CDK4 complex is detected, which is replaced by cyclin D2/3-CDK4/6-p27 complex following density arrest. During endodermal differentiation kinase-inactive cyclin D2/D3-CDK4-p27 complexes are formed. Neural differentiation specifically induces cyclin D1 at the expense of cyclin D3 and results in predominant formation of cyclin D1/D2-CDK4-p27 complexes. Differentiation is accompanied by cytoplasmic accumulation of cyclin Ds and CDK4/6, which in neural cells are associated with neural outgrowths. Most phenomena found here can be reproduced in mouse embryonic stem cells. In summary, our data demonstrate (i) that individual cyclin D isoforms are utilized in cells lineage specifically, (ii) that fundamental difference in the function of CDK4 and CDK6 exists, and (iii) that cyclin D-CDK4/6 complexes function in the cytoplasm of differentiated cells. Our study unravels another level of complexity in G(1)/S transition-regulating machinery in early embryonic cells.

• MeSH
• biologické modely MeSH
• buněčná diferenciace MeSH
• buněčný rodokmen MeSH
• cyklin A metabolismus   MeSH
• cyklin D1 MeSH
• cyklin E metabolismus   MeSH
• cyklin-dependentní kinasa 4 metabolismus   MeSH
• cyklin-dependentní kinasa 6 metabolismus   MeSH
• cykliny metabolismus   MeSH
• embryo savčí cytologie   metabolismus   MeSH
• embryonální kmenové buňky metabolismus   MeSH
• financování organizované MeSH
• G1 fáze MeSH
• inhibitor p27 cyklin-dependentní kinasy metabolismus   MeSH
• intracelulární prostor metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• proliferace buněk MeSH
• S fáze MeSH
• transport proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Centrosome abnormalities are observed in human cancers and have been associated with aneuploidy, a driving force in tumour progression. However, the exact pathways that tend to cause centrosome abnormalities have not been fully elucidated in human tumours. Using a series of 68 non-small-cell lung carcinomas and an array of in vitro experiments, the relationship between centrosome abnormalities, aneuploidy, and the status of key G1 to S-phase transition cell-cycle molecules, involved in the regulation of centrosome duplication, was investigated. Centrosome amplification and structural abnormalities were common (53%), were strongly related to aneuploidy, and, surprisingly, were even seen in adjacent hyperplastic regions, suggesting the possibility that these are early lesions in lung carcinogenesis. Cyclin E and E2F1 overexpression, but not p53 mutation, was observed to correlate with centrosome abnormalities in vivo (p = 0.029 and p = 0.015, respectively). This was further strengthened by the observation that cyclin E was specifically present in the nucleus and/or cytoplasm of the cells that contained centrosome aberrations. The cytoplasmic cyclin E signal may be attributed, in part, to the presence of truncated low-molecular-weight isoforms of cyclin E. In order to isolate the effect of cyclin E on the appearance of centrosome abnormalities, a U2OS tetracycline-repressible cyclin E cell line that has a normal centrosome profile by default was used. With this system, it was confirmed in vitro that persistent cyclin E overexpression is sufficient to cause the appearance of centrosome abnormalities. Copyright 2006 Pathological Society of Great Britain and Ireland.

• MeSH
• aneuploidie * MeSH
• centrozom * ultrastruktura   MeSH
• cyklin E * genetika   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• exprese genu MeSH
• geny p53 MeSH
• hybridizace in situ MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory plic genetika   patologie   MeSH
• nemalobuněčný karcinom plic genetika   patologie   MeSH
• neparametrická statistika MeSH
• regulace genové exprese u nádorů MeSH
• rozdělení chí kvadrát MeSH
• senioři MeSH
• transkripční faktor E2F1 genetika   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH

Recent studies have indicated the existence of tumorigenesis barriers that slow or inhibit the progression of preneoplastic lesions to neoplasia. One such barrier involves DNA replication stress, which leads to activation of the DNA damage checkpoint and thereby to apoptosis or cell cycle arrest, whereas a second barrier is mediated by oncogene-induced senescence. The relationship between these two barriers, if any, has not been elucidated. Here we show that oncogene-induced senescence is associated with signs of DNA replication stress, including prematurely terminated DNA replication forks and DNA double-strand breaks. Inhibiting the DNA double-strand break response kinase ataxia telangiectasia mutated (ATM) suppressed the induction of senescence and in a mouse model led to increased tumour size and invasiveness. Analysis of human precancerous lesions further indicated that DNA damage and senescence markers cosegregate closely. Thus, senescence in human preneoplastic lesions is a manifestation of oncogene-induced DNA replication stress and, together with apoptosis, provides a barrier to malignant progression.

• MeSH
• buněčné linie MeSH
• cyklin E genetika   MeSH
• DNA MeSH
• geny mos MeSH
• inhibitor p16 cyklin-dependentní kinasy fyziologie   MeSH
• invazivní růst nádoru genetika   MeSH
• jaderné proteiny genetika   MeSH
• lidé MeSH
• myši MeSH
• nádorová transformace buněk * genetika   MeSH
• onkogeny * MeSH
• poškození DNA * MeSH
• prekancerózy genetika   patologie   MeSH
• proteiny buněčného cyklu genetika   MeSH
• replikace DNA MeSH
• stárnutí buněk * genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH