Figure 1. Calcitriol and astemizole antiproliferative effects in cultured breast cancer cells.

Cells were incubated in the presence of different astemizole (A) or calcitriol (B) concentrations during 6 days. The culture media was not changed during the incubation period. Proliferation was determined measuring the metabolic activity of viable cells by using the XTT colorimetric method. Both calcitriol and astemizole inhibited cell proliferation in a concentration-dependent manner. Results are the mean ± S.D. of sextuplicate determinations and represent at least three different experiments. Based on the IC₅₀ values, the sensitivity to astemizole was: IDC-2> SUM-229PE > T-47D > IDC-1, while for calcitriol was: IDC-2> IDC-1> SUM-229PE. T-47D was rather resistant to calcitriol and therefore omitted from the graph. One-way ANOVA followed by Dunnett's test indicated a significant statistical significance (P<0.001) for each concentration tested vs vehicle, starting from 1.5 µM (A) and 1 nM (B). The only exception was IDC-2 in panel (A), which was significant (P<0.001) starting from 1.0 µM.