Search results for "53"
showing 10 items of 2908 documents
Clear signature of the (2 x 1) reconstruction of calcite (1014).
2010
Calcite is a mineral of fundamental importance that plays a crucial role in many fields of research such as biomineralization, biomolecule adsorption, and reactivity as well as industrial and daily life applications. Consequently, the most stable cleavage plane of calcite has been studied extensively using both direct imaging techniques such as atomic force microscopy as well as spectroscopic and diffraction techniques. Several surface structures have been reported for the (10 (1) over bar4) cleavage plane of calcite differing from the simple bulk-truncated structure and an ongoing controversy exists in literature whether the cleavage plane exhibits a (2 x 1) reconstruction or not. We study…
El mejor pastor descalzo, san Pascual Baylón o la incursión teatral de Ginés Campillo de Bayle
2016
Resumen: Cuando los ultimos decenios del siglo XVII iban marcando el final de la Casa de Austria en Espana, un clerigo nacido en Elche (Alicante), Gines Campillo de Bayle, intento su incursion en el mundo literario de la epoca. Su figura y obra, por un motivo u otro, siempre han estado rodeadas por un entorno de misterio, desgraciada fortuna y escasa estimacion. Valorado con precaucion por unos pocos, ignorado o criticado por la mayoria, gran parte de su produccion lirica, narrativa y teatral ha conseguido llegar, a pesar de todo, a nuestras manos. Un ejemplo de lo senalado es la comedia teatral, asi titulada por el propio autor, El mejor pastor descalzo, san Pascual Baylon ; toda una demos…
TP53 mutations and hepatocellular carcinoma: insights into the etiology and pathogenesis of liver cancer.
2007
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and the major risk factors include chronic infections with the hepatitis B (HBV) or C (HCV) virus, and exposure to dietary aflatoxin B(1) (AFB(1)) or alcohol consumption. Multiple genetic and epigenetic changes are involved in the molecular pathogenesis of HCC, for example, somatic mutations in the p53 tumor suppressor gene (TP53) and the activation of the WNT signal transduction pathway. AFB(1) frequently induces G:C to T:A transversions at the third base in codon 249 of TP53 and cooperates with HBV in causing p53 mutations in HCC. The detection of TP53 mutant DNA in plasma is a biomarker of both AFB(1) exposur…
MYCN sensitizes human neuroblastoma to apoptosis by HIPK2 activation through a DNA damage response.
2010
Abstract MYCN amplification occurs in approximately 20% of human neuroblastomas and is associated with early tumor progression and poor outcome, despite intensive multimodal treatment. However, MYCN overexpression also sensitizes neuroblastoma cells to apoptosis. Thus, uncovering the molecular mechanisms linking MYCN to apoptosis might contribute to designing more efficient therapies for MYCN-amplified tumors. Here we show that MYCN-dependent sensitization to apoptosis requires activation of p53 and its phosphorylation at serine 46. The p53S46 kinase HIPK2 accumulates on MYCN expression, and its depletion by RNA interference impairs p53S46 phosphorylation and apoptosis. Remarkably, MYCN ind…
Selective induction of apoptosis in multidrug resistant HL60R cells by the thiazolobenzoimidazole derivative 1-(2,6-difluorophenyl)-1H,3H-thiazolo [3…
1999
We investigated the antitumour effects of 1-(2,6-difluorophenyl)-1H,3H-thiazolo [3,4-a]benzimidazole (TBZ) a new anti-HIV-1 agent, on human promyelocytic HL60 leukaemia, both a parental and a multidrug resistant form (HL60R). HL60R overexpresses P-glycoprotein and, like HL60, lacks p53 protein expression. HL60 and HL60R show similar levels of Bcl-2 protein. In contrast to the conventional chemotherapeutic agents daunorubicin, etoposide and mitoxantrone, TBZ caused equal or even greater cytotoxicity in HL60R than in HL60, and this result was associated with a more marked induction of apoptosis in the drug resistant cells. The antitumour activity of TBZ occurred in the range of concentrations…
Hepatitis C Virus Core Protein Inhibits Tumor Suppressor Protein Promyelocytic Leukemia Function in Human Hepatoma Cells
2005
Abstract Tumor suppressor protein promyelocytic leukemia (PML) is implicated in apoptosis regulation and antiviral response. PML localizes predominantly to PML-nuclear bodies (PML-NB), nuclear macromolecular complexes regulating tumor suppressor protein p53 activity. Consistent with the function of PML in the cellular antiviral response, PML-NBs represent preferential targets in viral infections. In the case of hepatitis C virus (HCV) infection, important characteristics are nonresponsiveness to IFN therapy and development of hepatocellular carcinoma. However, the mechanisms which lead to the development of hepatocellular carcinoma are largely unknown. Here, we show that HCV core protein lo…
In human retinoblastoma Y79 cells okadaic acid-parthenolide co-treatment induces synergistic apoptotic effects, with PTEN as a key player.
2013
Retinoblastoma is the most common intraocular malignancy of childhood. In developing countries, treatment is limited, long-term survival rates are low and current chemotherapy causes significant morbidity to pediatric patients and significantly limits dosing. Therefore there is an urgent need to identify new therapeutic strategies to improve the clinical outcome of patients with retinoblastoma. here, we investigated the effects of two natural compounds okadaic acid (OKa) and parthenolide (PN) on human retinoblastoma Y79 cells. For the first time we showed that OKa/PN combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by lowering in p-akt levels, increasin…
Transcriptomic responses generated by hepatocarcinogens in a battery of liver-based in vitro models
2013
As the conventional approach to assess the potential of a chemical to cause cancer in humans still includes the 2-year rodent carcinogenicity bioassay, development of alternative methodologies is needed. In the present study, the transcriptomics responses following exposure to genotoxic (GTX) and non-genotoxic (NGTX) hepatocarcinogens and non-carcinogens (NC) in five liver-based in vitro models, namely conventional and epigenetically stabilized cultures of primary rat hepatocytes, the human hepatoma-derived cell lines HepaRG and HepG2 and human embryonic stem cell-derived hepatocyte-like cells, are examined. For full characterization of the systems, several bioinformatics approaches are emp…
Definitive evidence for Club cells as progenitors for mutantKras/Trp53‐deficient lung cancer
2021
Accumulating evidence suggests that both the nature of oncogenic lesions and the cell-of-origin can strongly influence cancer histopathology, tumor aggressiveness and response to therapy. Although oncogenic Kras expression and loss of Trp53 tumor suppressor gene function have been demonstrated to initiate murine lung adenocarcinomas (LUADs) in alveolar type II (AT2) cells, clear evidence that Club cells, representing the second major subset of lung epithelial cells, can also act as cells-of-origin for LUAD is lacking. Equally, the exact anatomic location of Club cells that are susceptible to Kras transformation and the resulting tumor histotype remains to be established. Here, we provide de…
Activity of O(6)-methylguanine-DNA methyltransferase in relation to p53 status and therapeutic response in ovarian cancer.
1999
The DNA-repair protein O(6)-methylguanine-DNA methyltransferase (alkyltransferase; MGMT) is a major determinant of resistance of cells to various alkylating cytostatic drugs. Its expression in tissues is highly variable, indicating complex regulatory mechanisms involved. Transfection-mediated expression of wild-type p53 has been shown to negatively regulate basal promoter activity of MGMT in vitro. To elucidate whether p53 is involved in regulation of MGMT in tumor tissue, we examined MGMT expression and the p53 status of 140 primary ovarian carcinomas and analyzed the data as to the correlation between MGMT and p53, as well as the survival response of the patients after chemotherapy. We sh…