Urethane dimethacrylate induces cytotoxicity and regulates cyclooxygenase-2, hemeoxygenase and carboxylesterase expression in human dental pulp cells
ACTA BIOMATERIALIA
Authors: Chang, Hsiao-Hua; Chang, Mei-Chi; Wang, Hsin-Hui; Huang, Guay-Fen; Lee, Yuan-Ling; Wang, Yin-Lin; Chan, Chiu-Po; Yeung, Sin-Yuet; Tseng, Shuei-Kuen; Jeng, Jiiang-Huei
Abstract
The toxic effect of urethane dimethacrylate (UDMA), a major dental resin monomer, on human dental pulp is not fully clear. In this study, we investigated the influence of UDMA on the cytotoxicity, cell cycle distribution, apoptosis and related gene expression of dental pulp cells. The role of reactive oxygen species, hemeoxygenase-1 (HO-1) and carboxylesterase (CES) in UDMA cytotoxicity, was evaluated. UDMA induced morphological changes of pulp cells and decreased cell viability by 29-49% at concentrations of 0.1-0.35 mM. UDMA induced G0/G1, G2/M cell cycle arrest and apoptosis. The expression of cdc2, cyclinB1 and cdc25C was inhibited by UDMA. Moreover, UDMA stimulated COX-2, HO-1 and CES2 mRNA expression of pulp cells. The cytotoxicity of UDMA was attenuated by N-acetyl-L-cysteine, catalase and esterase, but was enhanced by Zn-protoporphyrin (HO-1 inhibitor), BNPP (CES inhibitor) and loperamide (CES2 inhibitor). Exposure of UDMA may potentially induce the inflammation and toxicity of dental pulp. These findings are important for understanding the clinical response of human pulp to resin monomers after operative restoration and pulp capping, and also provide clues for improvement of dental materials. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Influence of UGT1A1 gene methylation level in colorectal cancer cells on the sensitivity of the chemotherapy drug CPT-11
BIOMEDICINE & PHARMACOTHERAPY
Authors: Xie, Fang-Wei; Peng, Yong-Hai; Wang, Wen-Wu; Chen, Xi; Chen, Xiong; Li, Jie; Yu, Zong-Yang; Ouyang, Xue-Nong
Abstract
Objective: To study the influence of the methylation level of UGT1A1 gene related to CPT-11 metabolic enzymes in colorectal cancer cells on the sensitivity of chemotherapy drugs. Methods: Test the changes in sensitivity of seven colorectal cancer cell strains that have been/not been subject to DAC treatment to CPT-11, analyze its correlation with CES2, UGT1A1 and GUSB mRNA expression according to IC50; screen the effective interference sequence of UGT1A1 siRNA, test the changes in cytotoxicity of CPT-11 after UGT1A1 siRNA is transfected, select RK0 cells and make them transfected with the chemosynthetic UGT1A1 siRNA after their UGT1A1 expression is restored with or without demethylation treatment. Results: The sensitivity of different colorectal cancer cell strains to CPT-11 showed difference (P < 0.05), UGT1A1 expression in colorectal cell lines had a negative correlation with the IC50 (r = 0.790648, P < 0.05), the interference efficiency of the screened UGT1A1 siRNA was up to 78%. The IC50 value of siRNA decreased by nearly one time after transfected with HT-29 (P < 0.01); which of methylated RK0 cells of UGT1A1 gene increased instead after the demethylation treatment. However, the IC50 value of the demethylation treatment group increased compared with the non-demethylation treatment group after UGT1A1 siRNA was transfected. Conclusions: The cytotoxicity of CPT-11 to colorectal cancer cells has a negative correlation with UGT1A1 expression, and positive correlation with CES2 and GUSB. The specific silencing UGT1A1 gene of siRNA could significantly increase the sensitivity of CPT-11 to the chemotherapy of colorectal cancer cells. UGT1A1 methylation was an important factor affecting the chemosensitivity of CPT-11. (C) 2014 Elsevier Masson SAS. All rights reserved.