Fig. 1.
Serotonin modulates MCF-7 cells proliferation and metabolism. a Proliferation rate, b cell viability, c apoptotic cells, d 5-HT receptor expression, e glucose consumption, f lactate production, g lactate production/glucose consumption ratio and h mitochondrial activity of MCF-7 cells treated with different 5-HT concentrations in the absence or the presence of 0.1 µM ketanserin (5-HT2A/C receptor antagonist). These plotted values are the mean ± S.E.M. of six independent experiments (n = 6). For a, b, c and d, the data were analysed by two-way ANOVA, followed by Sidak’s post test and * means P < 0.05 compared with the black bar of the same group. For e, f and h, except for the results in the absence of 5-HT, the differences between each value in the absence and in the presence of ketanserin were significant (P < 0.05; two-way ANOVA, followed by Sidak’s post test). For g, the differences were significant at the concentrations of 5, 10 and 20 µM 5-HT (P < 0.05; two-way ANOVA, followed by Sidak’s post test). The enzymatic activity of PK (i) and the levels of mRNA of PKM2 (j) are shown. For PK activity, plotted values are the mean ± S.E.M. of six independent experiments (n = 6; data were analysed by two-way ANOVA, followed by Sidak’s post test and * means P < 0.05 compared with the black bar of the same group). For PKM2 mRNA expression, plotted values are the mean ± S.E.M. of six independent experiments (n = 6; * means P < 0.05, Student’s t test). k Representative western blot of evaluation of PKM2 expression. l Quantification of the western blots of evaluation of PKM2 expression of three independent experiments (n = 3). Quantification (m) and representative western blots (o) of phosphorylation of ERK1/2 in MCF-7 cells treated with 5-HT and ketanserin (n = 3; * means P < 0.05 as compared with control in the absence of 5-HT, Student’s t test). Quantification (o) and representative western blots (n) of phosphorylation of cPLA2 in MCF-7 cells treated with 5-HT, ketanserin and LY3214996 (n = 3; * means P < 0.05 as compared with control in the absence of 5-HT, Student’s t test). q Pyruvate kinase activity in the absence or presence of 10 µM 5-HT and 50 nM LY3214996 (ERK1/2 inhibitor). The results for enzyme activity are from five independent experiments (n = 5, * means P < 0.05 as compared with control in the absence of LY3214996 and the bracket indicates P < 0.05 as compared with the absence of 5-HT; two-way ANOVA, followed by Sidak’s post test). Plotted results are expressed as mean ± S.E.M.