Prolyl oligopeptidase participates in cell cycle progression in a human neuroblastoma cell line

► We examined the effects of prolyl oligopeptidase (POP) inihibitors on cell growth. ► POP inhibitors suppressed the cell growth without cell death. ► The growth inhibition was associated with G0/G1 arrest. ► Knockdown of POP also led to inhibition of cell growth. ► POP is a part of the machinery that controls the cell cycle.