Image distances were calibrated using

a hemocytometer grid photographed on the same microscope and at the same magnification as the histology images, allowing a pixel to microns conversion factor to be selleck chemicals llc obtained at 400X magnification. One pixel was equal to 0.16722 μm. For each individual Selleck Compound Library mouse, twenty measurements were recorded and the values averaged for analysis. For western blot analysis, excised skin was placed on a glass plate on ice followed by removal of the epidermis with a razor blade. The epidermal scrapings were placed into RIPA lysis buffer (50 mM Tris–HCl, pH7.4, 1% NP-40, 150 mM NaCl, 1 mM EDTA, 1 mM PMSF, 1ug/mL leupeptin, 1ug/mL aprotinin, 1 mM Na3VO4, 1 mM NaF [Abcam, Cambridge, MA], screening assay and 1X protease inhibitor cocktail [Sigma-Aldrich, St. Louis, MO]), and homogenized on ice using a polytron homogenizer with 3 bursts of 30 sec each, followed by intermittent resting 10 sec between each burst and then centrifuged at 14,000 x g for 15 min at 4 °C. The supernatant (epidermal lysate) was collected, quantitated using Bio-Rad Protein Dye and according to the method of Bradford as previously described [40], and used for Western blot analysis. Epidermal lysates were separated by SDS-PAGE, electrophoretically transferred to a PVDF membrane, followed by staining with Ponceau S to assure efficient transfer. The blots were probed with antibodies

for Stat3 and PTyr705Stat3 (Cell Signaling Technology, Inc., Beverly,

MA) and signal intensity quantitated as previously described [15]. Tumor study K5.Stat3C (male Oxalosuccinic acid and female) mice (6–8 weeks of age) were initiated with 25 nmol DMBA and then treated with TPA (6.8 nmol) twice a week for the duration of the study as previously described [17]. Mice were pre-treated with 340 nmol ACA or 2.2 nmol FA 5 min prior to each TPA treatment. Mice were palpated for tumors twice weekly for the duration of the study. The numbers of subjects in each group were 14 (TPA only), 10 (ACA/TPA) and 6 (FA/TPA). At the end of the study, mice were euthanized, and skin and tumors were removed for histopathological analyses and immunohistochemistry (IHC). Statistical analysis Statistical analysis was performed using GraphPad Prism R version 3.0 software for Windows (GraphPad Software, San Diego, CA). The statistical analysis used for these studies was One way ANOVA followed by Tukey’s Multiple Comparison Test as the post test, with p < 0.05 being the level of significance. For the tumor study, multiplicity was analyzed using the Kruskal-Wallis non-parametric test (GraphPad Prism R version 5.0 for Mac). Results Effects of ACA on cells that overexpress Stat3 In order to determine whether these cells were sensitive to the antiproliferative and/or cell killing effects of ACA, a dose response viability assay was performed.