Apoptosis and cytolysis induced by giganteosides and hederacolchisides in HL-60 cells.

UNLABELLED: The viability, cytolysis and apoptosis-mediated cellular death induced by giganteosides D and E (Gig-D and Gig-E) and hederacolchisides A and A1 (Hcol-A and Hcol-A1) were analysed in HL-60 cells. MATERIALS AND METHODS: The end-point metabolic (WST1) and lactate dehydrogenase (LDH) assays were used. Cell cycle analysis and apoptosis were measured by flow cytometry, DNA laddering and caspase-3 analyses. RESULTS: the HL-60 cell line was more sensitive to Hcol-A1 and Gig-D (IC50 3-5 microM) than to Gig-E and Hcol-A (IC50 8-13 microM; WST1 assay). This was related to LDH release. The induction of apoptosis could be detected without caspase-3 activation after 24 h of treatment. DNA fragmentation could be detected only with Gig-D. With Hcol-A1 and Gig-D, an accumulation of cells in the S-phase and an increase of cells in sub-G1 peak were observed. By the annexinV-fluorescein isothiocyanate (FITC)/7-amino-actinomycin D (AAD) assay, the majority of cells were in late apoptosis with Gig-D, and in necrosis with Hcol-A1. CONCLUSION: Hcol-A1 is more cytotoxic than Gig-D, followed by Gig-E and finally Hcol-A. This is related to a membrane permeabilization effect, leading to cytolysis.

Pores formation on cell membranes by hederacolchiside A1 leads to a rapid release of proteins for cytosolic subproteome analysis.

Hederacolchiside A1 was used to progressively permeabilize the membrane of human melanoma MEL-5 cells. Holes formation was followed by Scanning Electron Microscopy and interaction of the saponin with cholesterol and phospholipids by TOF-SIMS. 2D-LC-MS/MS and 2D-SDS-PAGE show that the release of soluble proteins into serum-free culture media increases with time. This can lead to a new rapid and efficient strategy to analyze the cytosolic subproteome and it opens the door to get information from the cytosolic compartment for clinical proteomic studies.