Epigallocatechin 3-O-gallate Induces 67 kDa Laminin Receptor-Mediated Cell Death Accompanied by Downregulation of ErbB Proteins and Altered Lipid Raft Clustering in Mammary and Epidermoid Carcinoma Cells

2014 ◽  
Vol 77 (2) ◽  
pp. 250-257 ◽  
Author(s):  
Maria-Magdalena Mocanu ◽  
Constanţa Ganea ◽  
Laura Georgescu ◽  
Tímea Váradi ◽  
Dilip Shrestha ◽  
...  
Keyword(s):  
Cell Death ◽  
Lipid Raft ◽  
Carcinoma Cells ◽  
Epidermoid Carcinoma ◽  
Laminin Receptor ◽  
Raft Clustering ◽  
Altered Lipid

Green tea polyphenol EGCG induces lipid-raft clustering and apoptotic cell death by activating protein kinase Cδ and acid sphingomyelinase through a 67 kDa laminin receptor in multiple myeloma cells

2012 ◽  
Vol 443 (2) ◽  
pp. 525-534 ◽  
Author(s):  
Shuntaro Tsukamoto ◽  
Keisuke Hirotsu ◽  
Motofumi Kumazoe ◽  
Yoko Goto ◽  
Kaori Sugihara ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Protein Kinase ◽  
Lipid Raft ◽  
Apoptotic Cell ◽  
Acid Sphingomyelinase ◽  
Laminin Receptor ◽  
Myeloma Cells ◽  
Raft Clustering ◽  
Protein Kinase Cδ

EGCG [(−)-epigallocatechin-3-O-gallate], the major polyphenol of green tea, has cancer chemopreventive and chemotherapeutic activities. EGCG selectively inhibits cell growth and induces apoptosis in cancer cells without adversely affecting normal cells; however, the underlying molecular mechanism in vivo is unclear. In the present study, we show that EGCG-induced apoptotic activity is attributed to a lipid-raft clustering mediated through 67LR (67 kDa laminin receptor) that is significantly elevated in MM (multiple myeloma) cells relative to normal peripheral blood mononuclear cells, and that aSMase (acid sphingomyelinase) is critical for the lipid-raft clustering and the apoptotic cell death induced by EGCG. We also found that EGCG induces aSMase translocation to the plasma membrane and PKCδ (protein kinase Cδ) phosphorylation at Ser664, which was necessary for aSMase/ceramide signalling via 67LR. Additionally, orally administered EGCG activated PKCδ and aSMase in a murine MM xenograft model. These results elucidate a novel cell-death pathway triggered by EGCG for the specific killing of MM cells.

Nitric Oxide Exposure of CC531 Rat Colon Carcinoma Cells Induces γ-glutamyltransferase which May Counteract Glutathione Depletion and Cell Death

2003 ◽  
Vol 37 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Nils-Erik Huseby ◽  
Nana Asare ◽  
Silje Wetting ◽  
Idun Merete Mikkelsen ◽  
Bente Mortensen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Death ◽  
Colon Carcinoma ◽  
Carcinoma Cells ◽  
Glutathione Depletion ◽  
Rat Colon ◽  
Colon Carcinoma Cells

scholarly journals Actin Depolymerization Transduces the Strength of B-Cell Receptor Stimulation

2005 ◽  
Vol 16 (5) ◽  
pp. 2275-2284 ◽  
Author(s):  
Shengli Hao ◽  
Avery August
Keyword(s):  
B Cell ◽  
Lipid Raft ◽  
Cell Activation ◽  
Cell Receptor ◽  
Dependent Manner ◽  
B Cell Activation ◽  
Erk Activation ◽  
Actin Depolymerization ◽  
Transcription Factor Activation ◽  
Raft Clustering

Polymerization of the actin cytoskeleton has been found to be essential for B-cell activation. We show here, however, that stimulation of BCR induces a rapid global actin depolymerization in a BCR signal strength-dependent manner, followed by polarized actin repolymerization. Depolymerization of actin enhances and blocking actin depolymerization inhibits BCR signaling, leading to altered BCR and lipid raft clustering, ERK activation, and transcription factor activation. Furthermore actin depolymerization by itself induces altered lipid raft clustering and ERK activation, suggesting that F-actin may play a role in separating lipid rafts and in setting the threshold for cellular activation.

scholarly journals Cytotoxic Influence of Khat (Catha edulis (Vahl) Forssk. ex Endl) on Oral Fibroblasts, Squamous Carcinoma Cells, and Expression of α Smooth Muscle Actin

2021 ◽  
Vol 11 (8) ◽  
pp. 3524
Author(s):  
Azeem Ul Yaqin Syed ◽  
Muhammad A. Ahmed ◽  
Eman I. AlSagob ◽  
Mansour Al-Askar ◽  
Abdulrahman M. AlMubarak ◽  
...  
Keyword(s):  
Cell Death ◽  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Control Cell ◽  
Squamous Carcinoma ◽  
Carcinoma Cells ◽  
Muscle Actin ◽  
Catha Edulis ◽  
Squamous Carcinoma Cells ◽  
Dose Dependent

The aim was to determine the cytotoxicity of Khat (Catha edulis (Vahl) Forssk. ex Endl) on normal oral fibroblasts (NOFs) and SCC4 (squamous carcinoma cells) along with expression of α-smooth muscle actin (α-SMA) in fibroblasts. Khat filtrate was prepared to obtain a concentrated viscous solution. NOFs and SCC4 cells were cultured in biological cabinets and were grown in Dulbeccos’ modified Eagles medium. Frozen cells were thawed at 37 °C and cell seeding was performed. NOFs and SCC4 cells were seeded on 96 well plates and allowed to attach. The medium was removed and a fresh medium containing different concentrations of Khat was added. The group without Khat served as a negative control and 4% paraformaldehyde as the positive control. Cell viability was assessed using the MTT assay and effect of Khat on fibroblast and SCC4 phenotypes was evaluated by immunostaining. Analysis of variance was used to assess data (p < 0.05). NOF 316 showed cell death in response to 4% paraformaldehyde, 12.5, 6.25, and 3.12 mg/mL of Khat. The highest concentration of Khat (25 mg/mL) failed to cause cytotoxicity of NOF 316. NOF 319 and NOF 26 displayed cell death at all concentrations of Khat, however, cytotoxicity was not dose dependent. NOF 18 and SCC4 cells showed dose-dependent cell death. NOF 316 showed α-SMA expression after 1 mg/mL of Khat exposure. Not all fibroblasts were α-SMA-positive, suggesting specific activation of a subset of fibroblasts. Khat is cytotoxic to NOF and SCC4 cells. Furthermore, it can also cause activation and phenotypic changes in oral fibroblasts, indicating a potential role in progression of oral squamous cell carcinoma.

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