Pro-apoptotic effects of parathyroid hormone in intestinal cells

GENTILI C; CALVO N; RUSSO DE BOLAND A

Mar del Plata, Buenos Aires

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Depending on the cell type involved, parathyroid hormone (PTH) has been shown to inhibit or promote the apoptosis. The objective of this study was to further delineate the role of PTH in the intestinal apoptosis using the human colonic Caco-2 cells. To that end, Caco-2 cells were exposed during 3 to 5 days to PTH (10-8 M). The hormone increases spontaneous Caco-2 cell apoptosis according as DNA laddering formation by agarose gel electrophoresis. Analysis of the reduction in the nuclear size by the nuclear-specific colorant DAPI reveals that PTH treatment increases the number of apoptotic nuclei in a time-dependent fashion, with the maximum effects achieved at 5 days (+600%). In addition, assessment of dead cells after PTH treatment by propidium iodide shows that the hormone increases the number of red-stained cells (+ 500%, 5 days). Evaluation of the cell survival by quantification of cell number using crystal violet staining reveals that PTH treatment diminishes the number of cells (- 58%, 5 days). Cell viability assays using resazurin, a dye that measure the metabolic capacity of cells, shows that PTH diminishes the number of viable cells (- 52% , 5 days). Taken together, our results confirm that PTH promotes the apoptosis of Caco-2 intestinal cells.