Figure 9.

The effect of geranylgeraniol (GGOH, 10 µM) on cell viability (MTT assay) affected by geranylgeranyl transferase I (GGTI-286, IC₅₀) in the presence or absence of chloroquine (CQ, 10 mM). Differentiating C2C12 myoblasts were exposed for 24, 72, or 120 h to GGTI-286 (IC₅₀), (Day 1—proliferating myoblasts; Day 3—differentiating myotubes; Day 5—differentiated myotubes). Neither CQ nor GGOH affected the cell viability in comparison to control untreated cells (p > 0.05); GGOH could not rescue the muscle cell viability reduced by GGTI-286 in proliferating myoblasts and differentiating and differentiated myotubes (p > 0.05). The effect of GGOH was not affected by CQ administration (p > 0.05); CQ effectively reversed the negative effect of GGTI-286 on cell viability. GGOH blocked the effect of CQ on the GGTI-286-dependent drop in cell viability in differentiating and differentiated myotubes (p < 0.001) but not in proliferating myoblasts (p > 0.05). * p < 0.05, ** p < 0.01, *** p < 0.001, for comparison between the means. Statistically significant differences from untreated control cells are marked by # (at least at the level of p < 0.05). The results are indicative of three independent experiments performed in eight replicates.