Search results for "Biological Phenomena"
showing 10 items of 102 documents
The role of Aurora-A inhibitors in cancer therapy
2007
Recently, new chemotherapy agents which target the non-structural components of mitosis have been developed. An important protein involved in several mitotic phases is the Aurora-A protein. By means of the phosphorylation of different substrates, Aurora-A regulates the correct development of the various phases of mitosis. The kinase activity of this protein makes Aurora-A an excellent candidate as an oncogene. The first data of Aurora-A involvement in cancer regarded the identification of Aurora-A overexpression in primary breast and colon tumour samples. With regard to the predictive role of Aurora-A, it has been shown that its overexpression disrupts the spindle checkpoint activated by pa…
Septins 2, 7 and 9 and MAP4 colocalize along the axoneme in the primary cilium and control ciliary length
2013
International audience; Septins are a large, evolutionarily conserved family of GTPases that form hetero-oligomers and interact with the actin-based cytoskeleton and microtubules. They are involved in scaffolding functions, and form diffusion barriers in budding yeast, the sperm flagellum and the base of primary cilia of kidney epithelial cells. We investigated the role of septins in the primary cilium of retinal pigmented epithelial (RPE) cells, and found that SEPT2 forms a 1:1:1 complex with SEPT7 and SEPT9 and that the three members of this complex colocalize along the length of the axoneme. Similar to observations in kidney epithelial cells, depletion of cilium-localized septins by siRN…
The Serine/Threonine Protein Phosphatase 2A (PP2A) Regulates Syk Activity in Human Platelets
2020
Distinct membrane receptors activate platelets by Src-family-kinase (SFK)-, immunoreceptor-tyrosine-based-activation-motif (ITAM)-dependent stimulation of spleen tyrosine kinase (Syk). Recently, we reported that platelet activation via glycoprotein (GP) VI or GPIb&alpha
CTCF and BORIS Regulate Rb2/p130 Gene Transcription: A Novel Mechanism and a New Paradigm for Understanding the Biology of Lung Cancer
2011
Abstract Although innumerable investigations regarding the biology of lung cancer have been carried out, many aspects thereof remain to be addressed, including the role played by the retinoblastoma-related protein Rb2/p130 during the evolution of this disease. Here we report novel findings on the mechanisms that control Rb2/p130 gene expression in lung fibroblasts and characterize the effects of Rb2/p130 deregulation on the proliferative features of lung cancer cells. We revealed for the first time that in lung fibroblasts the expression of Rb2/p130 gene is directly controlled by the chromatin insulator CCCTC-binding factor, CTCF, which by binding to the Rb2/p130 gene promoter induces, and/…
BCL2 gene polymorphisms and splicing variants in chronic myeloid leukemia.
2015
Recent data suggest that constitutional genetic variation in the antiapoptotic BCL2 gene could be associated with the susceptibility to develop chronic myeloid leukemia (CML) and the clinical outcome in several hematological malignancies. The present study examines whether BCL2 single nucleotide polymorphisms (SNPs) predispose to CML or may potentially influence the disease characteristics at diagnosis. Notably, no association was observed between the four candidate BCL2 SNPs and the risk of developing CML. Instead, the 4777C>A (rs2279115) and the 5735A>G (rs1801018) SNPs were significantly associated with the disease risk profile as determined by the Sokal score. We found that such polymor…
Differences in the mechanisms of growth control in contact-inhibited and serum-deprived human fibroblasts
1997
In the present work we studied mechanisms of growth control in contact-inhibited and serum-deprived human diploid fibroblasts. The observation that the effects on [3H]thymidine incorporation and reduction of retinoblastoma gene product-phosphorylation were additive when contact-inhibition and serum-deprivation were combined led us to the conclusion that the underlying mechanisms might be different. Both contact-inhibition and serum-deprivation led to a strong decrease of cdk4-kinase-activity and cdk2-phosphorylation at Thr 160, while the total amounts of cdk4 and cdk2 remained constant. In contact-inhibited cells, we revealed a strong protein accumulation of the cdk2-inhibitor p27 and a sli…
Cyclin dependent kinase-1 (Cdk-1) inhibition as a novel therapeutic strategy against pancreatic ductal adenocarcinoma (pdac)
2021
Simple Summary Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers in humans, due to late diagnosis and limited treatment possibilities. Improved treatment for PDAC patients is warranted. Cyclin-dependent kinase 1 (CDK1) is a stimulator of cell cycle progression and its activity is regularly enhanced in pancreatic cancer cells. Therefore, CDK1 has been proposed as a novel drug target to treat patients with PDAC. This review describes the potential of CDK1 inhibition as a treatment for PDAC by outlining the molecular pathways influenced by CDK1 inhibition and new therapeutic strategies. Abstract The role of CDK1 in PDAC onset and development is two-fold. Firstly, since …
R-Roscovitine (Seliciclib) prevents DNA damage-induced cyclin A1 upregulation and hinders non-homologous end-joining (NHEJ) DNA repair.
2010
Abstract Background CDK-inhibitors can diminish transcriptional levels of cell cycle-related cyclins through the inhibition of E2F family members and CDK7 and 9. Cyclin A1, an E2F-independent cyclin, is strongly upregulated under genotoxic conditions and functionally was shown to increase NHEJ activity. Cyclin A1 outcompetes with cyclin A2 for CDK2 binding, possibly redirecting its activity towards DNA repair. To see if we could therapeutically block this switch, we analyzed the effects of the CDK-inhibitor R-Roscovitine on the expression levels of cyclin A1 under genotoxic stress and observed subsequent DNA damage and repair mechanisms. Results We found that R-Roscovitine alone was unable …
Cleavage of CD95 by matrix metalloproteinase-7 induces apoptosis resistance in tumour cells
2004
The ability of tumour cells to resist apoptosis-inducing signals by cytotoxic T cells may decide the success or failure of tumour elimination. An important effector of apoptosis is the CD95/CD95 ligand system (APO-1/Fas) that mediates perforin-independent cytotoxic T-cell killing of tumour cells. We propose a new strategy by which tumour cells can resist CD95-induced apoptosis. We identified matrix metalloproteinase-7, MMP-7 (Martilysin), as the first physiologically relevant protease that can specifically cleave CD95. MMP-7 is of unique importance because it is produced by the tumour cells themselves at early stages of tumour development. Microsequencing of the positions in CD95 cleaved by…
Aurora-A Transcriptional Silencing and Vincristine Treatment Show a Synergistic Effect in Human Tumor Cells
2008
Aurora-A is a centrosome-associated serine/threonine kinase that is overexpressed in multiple types of human tumors. Primarily, Aurora-A functions in centrosome maturation and mitotic spindle assembly. Overexpression of Aurora-A induces centrosome amplification and G 2 /M cell cycle progression. Recently, it was observed that overexpression of Aurora-A renders cells resistant to cisplatin (CDDP)-, etoposide-, and paclitaxel-induced apoptosis.Our results indicate that already in initial stages of cancer progression Aurora-A overexpression could have a major role in inducing supernumerary centrosomes and aneuploidy, as shown by immunohistochemistry on tissue sections from various stages of hu…