Pargyline reduces oncogene-driven tumor growth in a postmenopausal xenograft model. (A) Ovarectomized nude mice were injected subcutaneously with MCF-7-PELP1 model cells. After 4 weeks, mice were treated with or without pargyline (n = 10). Tumor growth was measured at weekly intervals. Tumor volume is shown. (B) Ki-67 expression as a marker of proliferation was analyzed by immunohistochemistry (IHC). Quantitation of Ki-67 staining was performed using the Ki-67 index as described in Materials and methods. (C) IHC analysis of indicated epigenetic marks was done on xenograft tumors that were treated with or without pargyline. (D) MCF-7-PELP1 and MCF-7-HER2 cells were treated with pargyline (3 mM), and chromatin immunoprecipitation analysis was performed using H3K9me2 antibodies and the status of epigenetic modification was analyzed using real-time PCR with aromatase P1.3/II promoter-specific primers. PELP1, proline glutamic acid and leucine-rich protein 1.