Proliferation inhibition, DNA damage, and cell-cycle arrest of human astrocytoma cells after acrylamide exposure
Journal
Chemical Research in Toxicology
Journal Volume
23
Journal Issue
9
Pages
1449-1458
Date Issued
2010
Author(s)
Abstract
Acrylamide (ACR) has been recognized as a neurological and reproductive toxin in humans and laboratory animals. This study aimed to determine the effects of ACR-induced DNA damage on cell cycle regulation in human astrocytoma cell lines. Treatment of U-1240 MG cells with 2 mM ACR for 48 h resulted in a significant inhibition of cell proliferation as evaluated by Ki-67 protein expression and MTT assay. The analysis of DNA damage with the comet assay showed that treatment of the cells with 0.5, 1, and 2 mM ACR for 48 h caused significant increases in DNA damage by 3.5-, 4-, and 14-fold, respectively. Meanwhile, analysis of cell-cycle arrest with flow cytometry revealed that the ACR treatments resulted in significant increases in the G0/G 1-arrested cells in a time- and dose-dependent manner. Expression of DNA damage-associated/checkpoint-related signaling molecules, including phosphorylated-p53 (pp53), p53, p21, p27, Cdk2, and cyclin D1, in three human astrocytoma cell lines (U-1240 MG, U-251 MG, and U-87 MG) was also analyzed by immunoblotting. Treatment of the three cell lines with 2 mM ACR for 48 h caused marked increases in pp53 and Cdk2, as well as decreases in cyclin D1 and p27. Moreover, increases in p53 and p21 were detected in both U-1240 and U-87 MG cells, whereas no marked change in p53 and a decrease in p21 were observed in U-251 MG cells. To address the involvement of ataxia telangiectasia mutated/ATM-Rad3-related (ATM/ATR) kinase in the signaling of ACR-induced G0/G1 arrest, caffeine was used to block the ATM/ATR pathway in U-1240 MG cells. Caffeine significantly attenuated the ACR-induced G0/G1 arrest as well as the expression of DNA damage-associated/checkpoint-related signaling molecules in a dose-dependent manner. This in vitro study clearly demonstrates the critical role of ATM/ATR in the signaling of ACR-induced cell-cycle arrest in astrocytoma cells. ? 2010 American Chemical Society.
SDGs
Other Subjects
acrylamide; ATM protein; caffeine; cyclin D1; cyclin dependent kinase 2; DNA; Ki 67 antigen; protein p21; protein p27; protein p53; article; astrocytoma cell; ataxia telangiectasia; cancer cell culture; cell cycle arrest; cell cycle G0 phase; cell cycle G1 phase; cell cycle regulation; cell proliferation; comet assay; controlled study; DNA damage; DNA determination; evaluation; flow cytometry; human; human cell; immunoblotting; in vitro study; molecule; protein expression; signal transduction; Acrylamide; Astrocytes; Astrocytoma; Cell Cycle; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Comet Assay; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; DNA Damage; DNA-Binding Proteins; G0 Phase; G1 Phase; Humans; Protein-Serine-Threonine Kinases; Tumor Suppressor Protein p53; Tumor Suppressor Proteins; Animalia; Ataxia telangiectasia
Type
journal article