Figure 3

LDs formed by the action of hGX convey a survival advantage to MDA-MB-231 cells during serum deprivation. (A) MDA-MB-231 cells were grown in complete culture medium in the presence of hGX for 48 h (1 nM). The cells were washed, sPLA₂-free and serum-free medium containing 0.02% BSA was added, and the cells incubated further without medium renewal. Neutral lipid content was measured by Nile red staining at the indicated time points during starvation. Note that LD content gradually decreased during serum-starvation and that cells that contained pre-formed hGX-induced LDs displayed an increased survival rate after 96 h of serum-starvation, as determined by the TMRM/YO-PRO-1 apoptosis assay (B). (C) Breast cancer cell lines were grown in complete culture medium with hGX (10 nM) in the presence or absence of varespladib (Var; 50 μM) for 24 h and cellular LD content was measured by Nile red staining. Values on the graphs are means ± SD of at least two experiments performed in duplicate and results that are statistically significant over control samples are indicated (*, P < 0.05; ***, P < 0.001; one-way ANOVA with Bonferroni adjustment).