S100A4 and cancer: To further characterize the potency of thephenylproline derivatives on cancer cells, their effect on proliferationhas been measured on HeLa and A549 cell lines, which are known toexpress S100A4.44,45 A cell proliferation assay wasperformed by cultivating cells for 48 h in complete media with variousconcentrations of inhibitors, up to 30 μM.