Figure 7.

Preparation of a fluorescently labeled mensacarcin and activity validation. A, synthesis of the rhodamine-mensacarcin conjugate. B, evaluation of the cytotoxic and apoptotic activity of the rhodamine-mensacarcin conjugate. Shown are dose-dependent growth inhibition and cytotoxicity of the rhodamine-mensacarcin conjugate in SK-Mel-5 cells (48-h treatment) compared with treatment with unlabeled mensacarcin determined by MTT assay and LDH assay. Vehicle-treated cells were grown in the presence of 1% (v/v) DMSO. Results are presented as mean ± S.D. (error bars) (n = 3). C, apoptotic cell death in SK-Mel-5 cells induced by TMR-mensa was evaluated by immunoblot analysis of caspase-3 activation and PARP-1 cleavage. Cells were grown in the presence of various concentrations of TMR-mensa or 0.5% (v/v) DMSO for 15 h. Analyzed lysates were pools of duplicates. β-Actin levels served as loading control.