Effects of Camphorquinone on Cytotoxicity, Cell Cycle Regulation and Prostaglandin E2 Production of Dental Pulp Cells: Role of ROS, ATM/Chk2, MEK/ERK and Hemeoxygenase-1

Abstract

Camphorquinone (CQ) is a popularly-used photosensitizer in composite resin restoration. In this study, the effects of CQ on cytotoxicity and inflammation-related genes and proteins expression of pulp cells were investigated. The role of reactive oxygen species (ROS), ATM/Chk2/p53 and hemeoxygenase-1 (HO-1) and MEK/ERK signaling was also evaluated. We found that ROS and free radicals may play important role in CQ toxicity. CQ (1 and 2 mM) decreased the viability of pulp cells to about 70% and 50% of control, respectively. CQ also induced G2/M cell cycle arrest and apoptosis of pulp cells. The expression of type I collagen, cdc2, cyclin B, and cdc25C was inhibited, while p21, HO-1 and cyclooxygenase-2 (COX-2) were stimulated by CQ. CQ also activated ATM, Chk2, and p53 phosphorylation and GADD45α expression. Besides, exposure to CQ increased cellular ROS level and 8-isoprostane production. CQ also stimulated COX-2 expression and PGE2 production of pulp cells. The reduction of cell viability caused by CQ can be attenuated by N-acetyl-L-cysteine (NAC), catalase and superoxide dismutase (SOD), but can be promoted by Zinc protoporphyin (ZnPP). CQ stimulated ERK1/2 phosphorylation, and U0126 prevented the CQ-induced COX-2 expression and prostaglandin E2 (PGE2) production. These results indicate that CQ may cause cytotoxicity, cell cycle arrest, apoptosis, and PGE2 production of pulp cells. These events could be due to stimulation of ROS and 8-isoprostane production, ATM/Chk2/p53 signaling, HO-1, COX-2 and p21 expression, as well as the inhibition of cdc2, cdc25C and cyclin B1. These results are important for understanding the role of ROS in pathogenesis of pulp necrosis and pulpal inflammation after clinical composite resin filling.

Protective effect of sildenafil on the genotoxicity and cytotoxicity in apolipoprotein E-deficient mice bone marrow cells

“…It is well known that elevated ROS levels alter cell cycle progression [27][28][29][30][31][32]. In the present study, we have found that oxidative stress change cell cycling in the bone marrow cells of atherosclerotic mice, as the bone marrow cells in apoE −/− mice were less proliferative than in WT mice (more cells in G 0 /G 1 phase, and less in S phase), suggesting that hypercholesterolemia induces a G 0 /G 1 arrest in bone marrow cells.…”

Effect of Butyrate on Collagen Expression, Cell Viability, Cell Cycle Progression and Related Proteins Expression of MG-63 Osteoblastic Cells

“…Inducing cytotoxicity, genotoxicity and inflammatory mediators’ release by a number of chemicals such as cadmium, areca nut, resin monomers and camphorquinone are associated with cellular ROS production [12,17,20,35]. The sources of ROS can be derived from host cells and microorganisms such as Porphyromonas gingivalis and Enterococci faecalis [36–38].…”

“…Cells were subsequently cultured in fresh medium containing different concentrations of butyrate (1–16 mM) for 5 days. Medium was aspirated and the insoluble formazan generated by viable cells were dissolved in dimethylsulfoxide (DMSO) and read against solvent blank (DMSO) at a wavelength of 540 nm (OD540) by an enzyme-linked immunosorbant assay (ELISA) reader (Multiskan Spectrum, USA) [17]. …”

“…After 24 h of cell attachment, they were exposed to different concentrations of butyrate (0–16 mM) for 24 h. After washing with PBS, cells were disrupted in lysis buffer (10 mM Tris-HCl, pH 7; 140 mM sodium chloride; 3 mM magnesium chloride; 0.5% NP-40; 2 mM phenylmethylsulfonyl fluoride; 1% aprotinin; and 5 mM dithiothreitol) [17,18,20]. Then aliquots (20–50 μg protein) of cell lysates were subjected to 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and conveyed to a polyvinylidene fluoride (PVDF) membrane.…”

“…After washed with PBS, cells were blocked in 5% bovine serum albumin (BSA) for 1 h and then incubated in primary antibodies (against type I collagen) at room temperature overnight. After washing by PBS, cells were incubated in corresponding secondary antibody in the dark for 1 h and counterstained for 30 min with 4',6-diamidino-2-phenylindole (DAPI, 1:1000) [17]. Finally the samples were mounted and observed/photographed by an Olympus IX71 inverted microscope and DP Controller/Manager software (Olympus Corporation).…”