Fig. 4

Lactate treatment enhances the resistance of cervical cancer cells to chemotherapeutics. Cells were incubated in the presence or absence of 20 mM L- or D-lactate for 24 h, followed by treatment with NCS (a), DOX (b) or CDDP (c) for the next 24 h in lactate-containing medium before seeding for colony formation in drug-free medium. The results are expressed as the means ± SEM of three independent experiments; cells treated with vehicle (white columns), cells treated with L-lactate (grey columns), cells treated with D-lactate (striped columns). Statistical significance was evaluated using one-way ANOVA followed by Tukey’s test. *P < 0.05, **P < 0.01 and ***P < 0.001 indicate significant differences compared to the untreated cells