Pargyline promotes inhibitory epigenetic modifications. (A) MCF-7-PELP1 cells and (B) MCF-7-HER2 cells were treated with pargyline (3 mM), and chromatin immunoprecipitation analysis was performed using H3K4me2-specific, H3K9me2-specific or H3K9ac-specific antibodies and the status of epigenetic modifications was analyzed using real-time PCR with the estrogen receptor target gene GREB1C proximal promoter-specific primers (B). Immunohistochemistry analysis of indicated epigenetic marks was done on (C) MCF-7 and (D) MCF-7-PELP1 xenografts that were treated with or without pargyline. Representative images are shown. Quantitation of staining performed as described in Materials and methods. ****P < 0.0001, ***P < 0.001, **P < 0.01, *P < 0.05. PAR, pargyline; PELP1, proline glutamic acid and leucine-rich protein 1.