In vitro anticancer studies of a small library of cyclic lipopeptides against the human cervix adenocarcinoma HeLa cells

Abstract

Various cyclic lipopeptides (CLPs, 23 compounds) were tested for their antitumor potential against human cervix adenocarcinoma HeLa cells. From the fast screening (tested concentrations: 0.01 and 10 μM) compound 10 ((12S,6S,10S,13S)-6-((R)-sec-butyl)-7-(2-(dodecylamino)-2-oxoethyl)-13-isopropyl- 82-nitro-2,5,12,15-tetraoxo-4,7,11,14-tetraaza-1(1,2)-pyrrolidina-8(1,4)-benzenacyclopentadecaphane- 10-carboxamide) was identified as active against HeLa cell line. The MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and CV (crystal violet) assays revealed at least five times higher cytotoxic potential of 10 (IC50 = 12.3±1.8 μM, MTT; 9.4±1.5 μM; CV) in comparison to control drug natural occurring CLP surfactin (IC50 = 64.9±0.8 μM, MTT; 76.2±1.6 μM; CV). The cell cycle analysis performed by DAPI (4',6-diamidino- 2-phenylindole) assay indicated the involvement of apoptosis in HeLa cell death upon treatment with 10, which was confirmed by apoptosis assay (annexin V/PI). Furthermore, during this process caspase activation could be detected (ApoStat assay, immunocytochemistry caspase-3 analysis). The flow cytometry analysis did not display induction of autophagy as a possible death mechanism in HeLa cells upon 10 treatment. The current findings could be used to design more effective CLPs based on 10 structure as potential anticancer agents.

Keywords

• cancer
• surfactin
• proliferation
• apoptosis
• cell cycle
• autophagy