Figure 3
Inhibitory activity of the released analogs and prodrug 2 in comparison to ML inhibitor. (A) The potency of compounds against recombinant PACE4 (Ki values) and PCa cell lines (IC50 values) as well as LDH release percentage as a measure of analogs’ acute cytotoxicity. The inhibitory constant (Ki) was calculated from the IC50 values using the equation of Cheng and Prusoff 50. Data are the mean ± SD of three independent experiments. The concentration of peptides that inhibited cell growth by 50% (IC50) was determined by MTT cell survival assays in DU145 and LNCaP cell lines. Data represent the mean ± SEM of three independent experiments. Acute cytotoxicity of the compounds at the selected concentrations was measured by lactate dehydrogenase (LDH) assay after 4 h of incubation with DU145 cells. NC – not calculable, indicates that the curve did not converged to 50% with doses up to 300 μM; ND – not determined. (B) Dose−response curves for the anti-proliferative effect of peptide 2 in DU145 and LNCaP cells. Previously published compound: [a] ref.12. ML inhibitor was used as control and was re-assayed in presented experiments. The obtained values are comparable to previously reported.
