Phospho-Smad2 Timecourse 73

Cells were incubated with 0.5 µM TGFβ for 30 minutes, in the absence or presence of 1 µM CDDO-Im, washed and incubated in media containing DMSO (Control), 1 µM CDDO-Im, 10 µM SB431542 (Sigma; St. Louis, MO) or both compounds (CDDO-Im + SB431542) at 37˚C for an additional 1 or 4 hours prior to lysis. Cell lysates were then analyzed by SDS-PAGE and immunoblotted with mouse anti- Smad2 or rabbit anti-phospho-Smad2 antibodies. Quantitation of the amount of phosphorylated Smad2 was carried out using QuantityOne software and normalized to Smad2 levels.

2.3.5 Immunofluorescence Microscopy 2.3.5.1 Smad2 Nuclear Accumulation

Cells were incubated with 0.5 µM TGFβ for 30 minutes in the absence or presence of 1 µM CDDO-Im, washed and incubated in media containing DMSO (Control), 1 µM CDDO-Im, 10 µM SB431542 or both compounds (CDDO-Im +

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SB431542) at 37˚C for an additional 1, 4 or 8 hours prior to fixation and permeabilization. Cells were then immunostained with anti-Smad2/3 antibody followed by Cy2-conjugated secondary antibody. DAPI staining was used to visualize cell nuclei. To quantify the amount of Smad2 nuclear localization, nuclear vs. cytoplasmic intensity profiles were generated from individual cells using ImagePro software. The quantitation of ≥ 100 cells/condition from 3 experiments was graphed as the nuclear signal minus the cytoplasmic signal vs. time (± SD).

2.3.5.2 Receptor Traffic

Receptor internalization studies were carried out as previously described (15). Briefly, HAT cells expressing extracellularly HA-tagged TβRII receptors were incubated with biotinylated-TGFβ for 2 hours at 4°C, washed and incubated with Cy3-streptavidin (Jackson Immunoresearch, West Grove, PA). Cells were then washed and incubated at 37°C for 1 hour with or without CDDO-Im. After the 37°C incubation, cells were fixed and incubated with mouse monoclonal anti-EEA1 antibodies and rabbit polyclonal anti- caveolin-1 antibodies. Anti-EEA1 and anti-caveolin-1 were detected using anti-mouse Cy5-conjugated antibodies and anti-rabbit Cy2-conjugated antibodies (Jackson Laboratories Inc.) respectively. Acid washing was carried out as previously described (15). Images were captured using an Olympus 1X81 inverted microscope equipped with fluorescence optics and deconvolved using ImagePro software.

2.3.5.3 EEA1 Distribution

To visualize the effect of CDDO-Im on EEA1-positive endosomes I assessed the staining pattern of the EEA1 compartment via immunofluorescence microscopy as described above with the exception that Cy2-labelled secondary antibodies were used. DAPI staining was used to visualize cell nuclei.

Staining observed to be localized to an area no greater than one half of the cell area and located more intensely on one side of the nucleus was scored as ‘peri-nuclear- positive’. If the intensity and distribution of the stain was equal throughout the cell body, it was scored as ‘dispersed’. The quantitation of ≥ 100 cells/condition from 3 experiments was graphed (± SD).

2.3.5.4 Cytoskeleton Studies

To visualize the effect of CDDO-Im on the microtubule cytoskeleton, cells were incubated for 1 hour with or without 1 µM CDDO-Im or 10 µM nocodazole (Sigma; Oakville, Canada) at 37˚C. Following fixation and permeabilization, cells were incubated with monoclonal anti-tubulin antibody followed by FITC-conjugated secondary antibodies. To assess the effect of CDDO-Im on the actin cytoskeleton, cells were incubated with 1 µM CDDO-Im or 10 µM cytochalasin B for 1 hour prior to fixation and permeabilization. The cells were then incubated for 30 minutes with Texas Red-conjugated phalloidin. Images were collected from a Leica DMIRE inverted microscope.

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2.3.6 Scratch Assays

Rat2 fibroblasts were grown to confluency and the cell monolayer was scratched with a sterile pipette tip to create a ‘wound’. For brightfield or DIC microscopy, images were collected using an Olympus IX81 inverted microscope. For immunofluorescence studies, cells were fixed, permeabilized and incubated with anti-CLIP170, anti-tubulin, anti-Rac1, anti-TβRII, anti-IQGAP1, anti-Par6 or anti-PKCζ antibodies. Following fluorescently-tagged secondary antibody incubation, the nuclei of cells were stained with DAPI and cells were visualized using an Olympus IX81 microscope controlled by QED Invivo software (Olympus, Canada).

The quantitation of the number of cells containing proteins at the leading edge of the cell was carried out using ≥ 100 cells/condition from 3 experiments (± SD). Briefly, a cell containing a positive immunofluorescence signal only along the edge of the plasma membrane that was directly adjacent to the scratch was scored as positive for leading edge localization. If a cell contained no signal along the adjacent edge to the scratch or contained dispersed signal along the complete cell periphery, it was scored as negative for leading edge staining.

2.3.7 CLIP170 Movies

Rat2 fibroblasts were microinjected with 0.25 nM cDNA encoding GFP-tagged CLIP170 protein and incubated at 37˚C for 4 hours. The cells were then incubated in

control media or media containing 0.1 µM or 1 µM CDDO-Im. Expressed GFP-tagged CLIP170 was visualized by immunofluorescence and time-lapse images were collected using a Leica DMIRE inverted microscope utilizing Openlab 3.0 software.

2.3.8 Cell Transfection

Cells were transfected with the constructs described in the figure legends using the calcium phosphate method as previously described (15).

2.3.9 Immunoprecipitation

Cells were lysed (50 mM Tris-HCl, pH 7.4, 150 mM NaCl, 1 mM EDTA, 0.5 % Triton X-100, 1 mM PMSF, and cocktail protease inhibitors) and centrifuged at 15,000 × gav at 4°C for 5 minutes. Aliquots of supernatants were collected for analysis of total protein concentration. The remaining cell lysates were incubated with primary antibody followed by incubation with protein G-sepharose. The precipitates were washed 3 times with lysis buffer, eluted with Laemmli sample buffer and subjected to SDS-PAGE and immunoblot analysis.

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