After incubation, the cells were washed with warm PBS, and the ROS production was measured by changes in fluorescence due to the intracellular production of DCF caused by the oxidation of DCFH2. 2% SDS, 10% glycerol and 5% \mercaptoethanol), and the mixture was boiled for 5?min. Equal amounts (50?g) of the denatured proteins were loaded onto each lane, separated on 8%\15% SDS polyacrylamide gels, followed by transfer of the proteins to polyvinylidene difluoride membranes overnight. Membranes were blocked with 0.1% Tween\20 in PBS containing 5% non\fat dried milk for 20?min at room temperature, and the membranes were Naftopidil (Flivas) reacted with primary antibodies overnight. The membranes were then incubated with a horseradish peroxidase\conjugated goat anti\rabbit or anti\mouse secondary antibody for 2?h. The blots were detected using an ImageQuant? LAS 4000 mini (Fujifilm, Tokyo, Japan) with an Enhanced Chemiluminescence substrate (Millipore, Billerica, MA). Densitometry analyses were performed using commercially available quantitative software (AlphaEase, Naftopidil (Flivas) Genetic Technology Inc. Miami, FL), with the control set as 1\fold, as shown below. 2.6. Immunofluorescence assay A7r5 cells (2??104 cells/well) were seeded onto an 8\well glass Tek chamber and pre\treated with FKA (2\30?M) for 2?h and then stimulated with or without TGF\1 (10?ng/mL) for 24?h. After treatment, cells were fixed in 2% paraformaldehyde for 15?min, permeabilized with 0.1% Triton X\100 for 10?min and then incubated for 1?h with anti\F\actin, anti\Smad3 or anti\Nrf\2 primary antibodies in 1.5% FBS. The cells were then incubated with a FITC (fluorescein isothiocyanate)\conjugated (488?nm) secondary antibody for an additional 1?h in 6% bovine serum albumin. Following this, cells were stained with 1?g/mL DAPI for 5?min. The stained cells were washed with PBS and visualized using a fluorescence microscope at 200 magnification. 2.7. Luciferase activity assay of Smad3 and ARE The Smad3 and ARE transcriptional activity was measured using a dual\luciferase reporter assay system (Promega, Madison, WI). A7r5 cells were cultured in 24\well plates that had reached 70%\80% confluence and incubated for 5?h with serum\free DMEM that did not contain antibiotics. The cells were then transfected with either a pcDNA vector or a Smad3 (pGL3\SBE4\Luc reporter vector) plasmid/ARE plasmid with \galactosidase using Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA). After plasmid transfection, cells were pre\treated with FKA 7.5?M for 0.5 to 4?h and then stimulated with or without TGF\1 (10?ng/mL) for 24?h. Following treatment, the cells were lysed, and their luciferase activity was measured using a luminometer (Bio\Tek instruments Inc, Winooski, VA). The luciferase activity was normalized to the \galactosidase activity in cell lysate, which was considered the basal level (100%). 2.8. In vitro wound\healing repair assay To assess the cell migration, A7r5 cells were seeded into a 12\well culture dish and grown in DMEM made up of 10% FBS to a nearly confluent cell monolayer. The cells were re\suspended in DMEM medium made Naftopidil (Flivas) up of 1% FBS, and a wound gap in the monolayers was carefully scratched using a culture insert. Cellular debris was removed by washing with PBS. Then, the cells were incubated with a non\cytotoxic concentration of FKA (2\30?M) for 2?h and stimulated with or without TGF\1 (10?ng/mL) for 24?h. The migrated cells were imaged (200 magnification) at 0 and 24?h to monitor the migration of cells into the wounded area, and the closure of the wounded area was calculated. 2.9. Cell invasion assay Invasion assay was performed using BD Matrigel invasion chambers (Bedford, MA, USA). For the assay, 10?L Matrigel (25?mg/50?mL) was applied to 8\m polycarbonate membrane filters, and 1??105 cells were seeded to the Matrigel\coated filters in 200?L of serum\free RAC1 medium containing FKA (2\30?M) and/or TGF\1 (10?ng/mL). The bottom chamber of the apparatus contained 750?L of complete growth medium. Cells were allowed to migrate for 24?h at 37C. After 24?h incubation, the non\migrated cells on the top surface of the membrane were removed with a cotton swab. The migrated cells on the bottom side of the membrane were fixed in cold 75% methanol for 15?min and washed 3 times with PBS. The cells were stained with Giemsa stain solution and then de\stained with PBS. Images were obtained using an optical microscope (200?? magnification), and invading cells were quantified by manual counting. The inhibition of invading cells was quantified and expressed on the basis of untreated control cells, which were set as 1\fold. 2.10. Measurement of intracellular ROS generation The accumulation of intracellular ROS in A7r5 cells was quantified by a fluorescence spectrophotometer using DCFH2\DA as described previously.30 Briefly, A7r5 cells at a density of 4??105 Naftopidil (Flivas) cells/well in 12\well plates were pre\treated with FKA.
After incubation, the cells were washed with warm PBS, and the ROS production was measured by changes in fluorescence due to the intracellular production of DCF caused by the oxidation of DCFH2