Activation of PPARγ induces NHE1 gene repression. (A) MCF-7 and MDA-MB-231 cells were exposed to 3 μM and 5 μM 15 d-PGJ2 for 24 h before NHE1 mRNA and protein levels were assessed as described in M&M. Relative NHE1 mRNA expression is expressed as percent of untreated control. Data shown is the mean of three experiments done in duplicate +/- SD. NHE1 protein expression in (B) MCF-7 and (C) MDA-MB-231 was analyzed by Western blot following 15 d-PGJ2 at doses indicated for 24 h. Equal loading ascertained using detection of β-actin.