n-(n-(3-5-difluorophenacetyl)alanyl)phenylglycine-tert-butyl-ester and Glioma

To explore the suppressing effect of γ-secretase inhibitor DAPT on proliferation of human glioma cell line SHG-44 in vitro and its mechanism.. The SHG-44 cell was treated by DAPT with different concentration. The proliferation of cells was detected by MTT assay; cell cycle and TSC of CD133(+) were determined by flow cytometry analysis technique; the key factor in Notch signaling pathway (Notch-1, Delta-1, Hes-1) was measured by reverse transcriptase-polymerase chain reaction and western blotting.. DAPT inhibited the growth and proliferation of SHG-44 cells significantly(P<0.05). And the inhibiting effect on SHG-44 cells produced by DAPT showed a dose-dependent manner. DAPT increased the rate of cells in G0/G1 phase of SHG-44 cells, while it decreased the rate of cells in S phase. TSC of CD133(+) was significantly reduced after DAPT treated SHG-44 cells. The expression of protein and mRNA of Notch-1, Delta-1 and Hes-1 were gradually downregulated with the increase of DAPT doses.. DAPT can downregulate these key factor in Notch signaling pathway, reduce the TSC of CD133+ and inhibit the proliferation of SHG-44 cells.

Topics: Antineoplastic Agents; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Shape; Dipeptides; Glioma; Humans; Signal Transduction

Both the Notch-signaling pathway and extracellular signal regulated kinase (ERK) cascade are involved in a wide variety of biological processes, such as proliferation, differentiation, survival, and tumorigenesis. Their dysregulation in recent studies have been shown to be associated with glioma formation. Here, we show that transforming growth factor-alpha (TGF-alpha) stimulated glioma cell line U251 growth and can partly compensate for the inhibitory effect of Notch-signaling inhibitor DAPT. The effect of TGF-alpha on ERK1/2 phosphorylation was prompt and transient and could be inhibited by mitogen-activated/extracellular signal-regulated kinase kinase 1/2 (MEK1/2) specific inhibitor PD98059. Moreover, TGF-alpha was capable of up-regulating Hairy-enhancer of split1 (Hes1) expression which was independent of Notch1 activation, and of introducing Hes1 nuclear import in the presence of ERK1/2 activation. Collectively, our data suggest a potential linkage between ERK activation and the Notch-signaling pathway.

Topics: Active Transport, Cell Nucleus; Amyloid Precursor Protein Secretases; Basic Helix-Loop-Helix Transcription Factors; Blotting, Western; Cell Line, Tumor; Cell Nucleus; Cell Proliferation; Dipeptides; Extracellular Signal-Regulated MAP Kinases; Flavonoids; Gene Expression Regulation, Neoplastic; Glioma; Homeodomain Proteins; Humans; Immunoglobulin J Recombination Signal Sequence-Binding Protein; Phosphorylation; Protease Inhibitors; Protein Kinase Inhibitors; Protein Transport; Receptors, Notch; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transcription Factor HES-1; Transforming Growth Factor alpha; Up-Regulation