1,721,098 research outputs found
Use of the comet test in the evaluation of multidrug resistance of human cell lines
No full textThe comet test is a reported method for measuring DNA damage in individual mammalian cells, In the present report, the ability of this test to detect multidrug resistance (MDR) was evaluated. For this purpose, two human leukemia, well-characterized parental cell lines, HL60 and GEM, and their derived multidrug-resistant cells, HL60/DNR and CEM/VBL, were cultured with or without different anti-cancer agents. To evaluate the comet test, two DNA-damaging agents were used: daunorubicin (DNR), which is involved in MDR, and ambamustine (AMBA), which is independent from MDR. Moreover, in order to evaluate the specificity of the comet test, the activity of vinblastine (VBL), an MDR-related, DNA-independent anti-cancer drug, was also tested. Finally, the specificity of the comet test in detecting MDR was confirmed by culturing parental or resistant cells with DNR with or without the revertant agent verapamil (VER). Results confirm that the comet test is able to predict cellular chemoresistance when DNA damaging agents are tested. Finally, experiments on the role of the comet test in evaluating certain aspects of DNA repair are discussed
A morphological study of the expression of the small G protein RhoA in resting and activated MDCK cells
No full textThe small G protein Rho subfamily controls several cellular events such as growth, movement, proliferation and differentiation by rearranging actin and cytoskeleton proteins. Most of these effects are mediated by the activation of growth factor and extracellular matrix molecule receptors, suggesting a role for Rho molecules in the transduction pathway of these receptors. Despite the importance of Rho peptides in fundamental cellular events, data on their subcellular immunolocalisation are sparse: here we investigated the expression and subcellular localisation of RhoA in resting (cultured on plastic) and activated (Matri-cell or hepatocyte growth factor) MDCK cells by immunoperoxidase and immunogold techniques. Resting MDCK cells contain detectable amounts of RhoA mainly localised in the cytoplasm; RhoA expression is significantly enhanced by Matri-cell substrates that promote translocation of RhoA at the membrane level. This enhancing effect is reduced after exposure to hepatocyte growth factor
Cellular distribution of RhoA in human embryonic and adult renal tissues and renal cell lines: morphofunctional implications.
No full textTGF-alpha mRNAexpression in renal organogenesis: a study in rat and human embryos.
No full textThe peptides belonging to the epidermal growth factor (EGF) family play a significant role in kidney development by binding the EGF receptor. Transforming growth factor-alpha (TGF alpha), a member of this family, is thought to be the fetal ligand of the EGF receptor. The present study aims to localize the TGF alpha transcripts in rat and human embryonic kidneys using a nonradioactive in situ hybridization method on paraffin-embedded embryonic samples. The results obtained in this study, beside demonstrating the usefulness of the nonradioactive technique for the detection of TGF alpha mRNA in paraffin sections, allowed TGF alpha-producing cells to be seen in developing kidneys. TGF alpha mRNA and its respective peptide were found in the primitive mesonephric structures and within metanephric blastema and ureteric bud cells. The presence of the TGF alpha gene transcript in the developing rat and human kidney suggests that the TGF alpha peptide is of embryonic origin and that it may contribute to renal organogenetic processes together with other growth factors
Cellular distribution of RhoA in human embryonic and adult renal tissues and renal cancer cell lines: morphofunctional implications
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The small peptide OGP(10-14) reduces proliferation and induces differentiation of TPO-primed M07-e cells through RhoA/TGFbeta1/SFK pathway
No full textBackground: Osteogenic growth peptide (OGP) is a 14-mer peptide found in relevant concentration in blood, and its carboxy-terminal fragment [OGP(10-14)] represents the active portion of the full-length peptide. In addition to stimulating bone formation, OGP(10-14) shows hematological activity. In fact, it highly enhances hematopoiesis-affecting stem progenitors. Moreover, OGP(10-14) reduces the growth and induces the differentiation of the hematological tumour cell line trombophoietin(TPO)- primed M07-e by interfering with RhoA and Src kinase pathways. In the present report, we went deeper into this mechanism and evaluated the possible interference of the OGP(10-14) signal pathway with TGFß1 and TPO receptor Mpl. Material/Methods: In OGP(10-14)-treated M07-e cells cultured with or without RhoA and Src kinases inhibitors (C3 and PP2), expression of TGFß1, Mpl, and Src kinases was analyzed by immunoperoxidase technique. Activated RhoA expression was studied using the G-LISATM quantitative test. Results: In M07-e cells, both OGP(10-14) and PP2 activate RhoA, inhibit Src kinases, reduce Mpl expression and increase TGFß1 expression. OGP(10-14) and PP2 show the same behavior, causing an additive effect when associated. Conclusions: OGP(10-14) induces TPO-primed M07-e cells differentiation through RhoA/TGFß1/SFKs signaling pathway. In particular OGP(10-14) acts as a Src inhibitor, showing the same effects of PP2
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