Figure 3.

Mg supplementation does not affect cancer cell sensitivity to CTX. (a) A representative dose-response curve of CaCo-2 cells exposed to CTX (24 h) in control medium (0.8 mM of MgSO₄, solid line and circles) or Mg-supplemented medium (5 mM of MgSO₄, dotted line and open circles). (b) Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 in CaCo2 cells challenged for 24h with EGF (10 ng/mL) with or without CTX (70 μg/mL) in control (0.8 mM of MgSO₄) or Mg-supplemented (5 mM of MgSO₄) medium, as assessed by Western blot analysis; a representative blot is shown. (c) Quantification of ERK1/2 phosphorylation by Western blot densitometry, normalized to total ERK1/2 levels (n = 3, mean ± SD). Two-way ANOVA indicated a very significant effect (p < 0.001) of EGF/CTX treatment, while Mg concentration had no significant effect (p = 0.70). The effect of CTX on unstimulated cells in control or Mg-supplemented medium is reported in Figure S3.