Figure 2

Greater peroxisome proliferator-activated receptor (PPAR)-selective antiproliferative and apoptotic responses potentiated by AGN194204 in retinoid X receptor (RXR)-α-overexpressing human breast cancer cell lines. (a) Triplicate cultures of estrogen receptor positive/retinoic acid (RA)-sensitive T47D cells were treated for 6 days with vehicle (con), 100 μmol/l of the PPAR-γ ligand γ-linolenic acid (LA), 100 nmol/l AGN194204 (AGN), or both compounds simultaneously (LA+AGN). Proliferation was monitored by cell counting at 2-day intervals using a hemacytometer. (b) Triplicate cultures of estrogen receptor negative/RA-resistant MDA-MB-468 cells were treated for 6 days with vehicle (con), 100 μmol/l LA, 100 nmol/l AGN194204, or both compounds simultaneously (LA+AGN). Proliferation was monitored by cell counting at 2-day intervals using a hemacytometer. (c) LA and AGN194204 inhibit S-phase progression in human breast cancer cell lines. The indicated cell lines were treated with 100 μmol/l LA or 100 nmol/l AGN194204 (AGN). The percentage of S-phase cells was determined by bromodeoxyuridine (BrdU) incorporation assay. (d) PPAR- and RXR-selective ligands alter expression of nonoverlapping sets of cell cycle regulatory proteins. Whole cell lysates from the indicated human breast cancer cell lines treated with 100 μmol/l LA for up to 24 hours were subjected to western blot with the antibodies shown on the left. Relative expression of each protein was determined using the same membrane. (e) Whole cell lysates from the indicated human breast cancer cell lines treated with 100 nmol/l AGN194204 for up to 24 hours were subjected to western blot with the antibodies shown on the left. Relative expression of each protein was determined using the same membrane.