Research Paper Volume 4, Issue 4 pp 270—278

Attenuation of constitutive DNA damage signaling by 1,25-dihydroxyvitamin D3


Figure 1. Effect of the treatment of A549 cells with 1,25-VD on the level of expression of γH2AX with respect to the cell cycle phase. Exponentially growing human pulmonary carcinoma A549 cells were untreated (Ctrl) or treated with 2 or 10 nM 1,25-VD for 24 or 48 h and expression of γH2AX was detected immunocytochemically using phospho-specific Ab targeting the phosphorylated S139 epitope; the intensity of fluorescence was measured by laser scanning cytometry (LSC) [70]. The numbers above the respective arrows indicate the percent reduction in intensity of immunofluorescence of the mean values of cell populations in G1, S and G2M phases of the cell cycle (gated as shown in the Ctrl panel) in the 1,25-VD-treated cells with respect to the untreated cells (Ctrl), in the same phase of cell cycle. Inserts show cellular DNA content histograms from the respective cultures. The skewed dash line in Ctrl panel shows the maximal level of fluorescence intensity of the cells stained with isotype control Ab.