Browsing by Subject "cell cycle"

Now showing 1 - 4 of 4

Open Access
Differential p21 expression after ionizing and UVC radiation in EBV-transformed lymphoblastoid cells
(2000) Moyret-Lalle, C.; Lalle P.; Pedeux, R.; Guillot, C.; Martel, S.; Magaud J.-P.; Puisieux, A.; Ozturk, M.
Responses to DNA-damaging agents appear to be coordinated by p53 through transcriptional activation of critical target genes. Among them, p21WAF1 encodes a protein preventing cells from entering S phase. It is not clear whether p53-mediated response varies depending on the type of DNA damage. Here, we have decided to compare the p53-mediated response of EBV-transformed lymphoblasts to ionizing radiation and UVC irradiation. We have shown that these cells respond to ionizing radiation by a cell cycle arrest as expected. Surprisingly they failed to do so after UVC treatment. Accordingly there was no significant induction of p21 protein in UVC exposed cells despite p53 accumulation. Using isogenic EBV-transformed lymphoblastoid cells expressing E6 protein of HPV18, we have demonstrated that there was no evidence of p53-dependent cell cycle arrest after UVC irradiation. These observations suggest that the p53-mediated response to UVC, in contrast to ionizing radiation, was compromised in EBV-transformed cells and might be cell type-dependent.
Open Access
Herpes simplex virus 1 amplicon vector-mediated siRNA targeting epidermal growth factor receptor inhibits growth of human glioma cells in vivo
(2005) Saydam O.; Glauser, D.L.; Heid I.; Turkeri G.; Hilbe, M.; Jacobs, A.H.; Ackermann, M.; Fraefel, C.
In primary glioblastomas and other tumor types, the epidermal growth factor receptor (EGFR) is frequently observed with alterations, such as amplification, structural rearrangements, or overexpression of the gene, suggesting an important role in glial tumorigenesis and progression. In this study, we investigated whether posttranscriptional gene silencing by vector-mediated RNAi to inhibit EGFR expression can reduce the growth of cultured human gli36 glioma cells. To "knock down" EGFR expression, we have created HSV-1-based amplicons that contain the RNA polymerase III-dependent H1 promoter to express double-stranded hairpin RNA directed against EGFR at two different locations (pHSVsiEGFR I and pHSVsiEGFR II). We demonstrate that both pHSVsiEGFR I and pHSVsiEGFR II mediated knock-down of transiently transfected full-length EGFR or endogenous EGFR in a dose-dependent manner. The knock-down of EGFR resulted in the growth inhibition of human glioblastoma (gli36-luc) cells both in culture and in athymic mice in vivo. Cell cycle analysis and annexin V staining revealed that siRNA-mediated suppression of EGFR induced apoptosis. Overall HSV-1 amplicons can mediate efficient and specific posttranscriptional gene silencing. Copyright © The American Society of Gene Therapy.
Open Access
A ranking-based meta-analysis reveals let-7 family as a meta-signature for grade classification in breast cancer
(Public Library of Science, 2015) Oztemur, Y.; Bekmez, T.; Aydos, A.; Yulug I.G.; Bozkurt, B.; Dedeoglu, B.G.
Breast cancer is one of the most important causes of cancer-related deaths worldwide in women. In addition to gene expression studies, the progressing work in the miRNA area including miRNA microarray studies, brings new aspects to the research on the cancer development and progression. Microarray technology has been widely used to find new biomarkers in research and many transcriptomic microarray studies are available in public databases. In this study, the breast cancer miRNA and mRNA microarray studies were collected according to the availability of their data and clinical information, and combined by a newly developed ranking-based meta-analysis approach to find out candidate miRNA biomarkers (meta-miRNAs) that classify breast cancers according to their grades and explain the relation between miRNAs and mRNAs. This approach provided meta-miRNAs specific to breast cancer grades, pointing out let-7 family members as grade classifiers. The qRTPCR studies performed with independent breast tumors confirmed the potential biomarker role of let-7 family members (meta-miRNAs). The concordance between the meta-mRNAs and miRNA target genes specific to tumor grade (common genes) supported the idea of mRNAs as miRNA targets. The pathway analysis results showed that most of the let-7 family miRNA targets, and also common genes, were significantly taking part in cancer-related pathways. The qRT-PCR studies, together with bioinformatic analyses, confirmed the results of meta-analysis approach, which is dynamic and allows combining datasets from different platforms. © 2015 Oztemur et al.
Open Access
Synthesis and anticancer activity evaluation of some benzothiazole-piperazine derivatives
(Bentham Science Publishers B.V., 2015) Gurdal, E.E.; Buclulgan, E.; Durmaz I.; Cetin-Atalay, R.; Yarim, M.
Synthesis, characterization and cytotoxic activities of ten benzothiazole-piperazine derivatives were reported. In vitro cytotoxic activities of compounds were screened against hepatocellular (HUH-7), breast (MCF-7) and colorectal (HCT-116) cancer cell lines by sulphorhodamine B assay. Based on the GI50 values of the compounds, most of the benzothiazole-piperazine derivatives are active against HUH-7, MCF-7 and HCT-116 cancer cell lines. Aroyl substituted compounds 1h and 1j were found to be the most active derivatives. In addition, further investigation of compounds 1h and 1j by Hoechst staining and FACS revealed that these compounds cause apoptosis by cell cycle arrest at subG1 phase. © 2015 Bentham Science Publishers.