PGP and cancer: To test if the potential P-gp inhibitors were specific to DU145-TXR cancer cells, the top compounds (70, 78, 96, 97, 101, 103, 111, 122 and 124) were tested with second set of paired cancer cell lines – the P-gp overexpressing, doxorubicin resistant A2780-ADR ovarian cancer cell line, and the parental, non-P-gp overexpressing A2780 line [9,43,44].