Caspase-3 inhibitor but not proteasomal inhibitor alters fluvastatin-mediated regulation of vimentin levels in MDA-MB-231 cells.

<p>A, MDA-MB-231 cells were treated with various concentrations of fluvastatin (0–20 µM) for a period of 24 h and at the end of the treatments trypsin-like and chymotrypsin-like activities of the 26S proteasome were measured using respective fluorogenic substrates as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108890#s2" target="_blank">materials and methods</a> section. B, is same as A except that cells were treated with fluvastatin (10 µM) for various time points (0–24 h). C, MDA-MB-231 cells were treated in the presence or absence of MG-132 (1 µM) for a period of 24 h and at the end of the treatments, vimentin and β-catenin protein levels were measured by Western blot analysis. D, MDA-MB-231 cells were pre-treated with caspase-3 inhibitor (50 µM) for a period of 6 h in the presence or absence of fluvastatin (10 µM) for a period of 24 h and vimentin protein levels were measured by Western analysis. Data represented are Mean±SD from at least three independent experiments. *, significantly different compared to untreated conditions; #, significantly different compared to MG-132 and fluva+MG-132 condition; **, significantly different compared to fluvastatin alone treated condition. Statistical significance was tested at P<0.05 level by two-tailed, unpaired, Student's t-test.