PRO-APOPTOTIC EFFECTS OF PTH IN INTESTINAL CELLS

CALVO N; GERMAN O L; RUSO DE BOLAND A; GENTILI C

BIOCHEMISTRY AND CELL BIOLOGY (ONLINE)

Biochemistry and Cell Biology NRC Research Press

Año: 2009 vol. 87 p. 389 - 400

1208-6002

Apoptosis, a form of programmed cell death, is a process fundamental to normal growth and development, immune response, tissue remodeling after injury or insult, and plays a critical role in maintaining homeostasis of the intestinal epithelium. Recently, it has become apparent that apoptosis is a crucial process in skeletal development and homeostasis and that signaling by the PTH receptor can either promote or suppress apoptosis depending on the cellular context. In this study we evaluate the role of PTH in the intestinal apoptosis using the human colonic Caco-2 cells. To that end, Caco-2 cells were exposed during 1 to 5 days to PTH (10-8 M). Evaluation of the cell survival using resazurin staining, 3-(4,5-dimethylthiazol-2-yl) -5-(3-carboxymethoxyphenyl) -2-(4-sulfophenyl)-2H-tetrazolium (MTS) staining and crystal violet staining reveals that PTH treatment diminishes the number of viable cells. Assessment of dead cells after PTH treatment by propidium iodide shows that the hormone increases the number of red-stained cells (+ 178%, 5 days). Moreover, we found that the hormone induces disruption of actin filaments with changes of cellular shape, alteration of cell-to-cell junctions, externalization of membrane phosphatidylserine and also chromatin condensation and DNA fragmentation of the nucleus, morphological features consistent with apoptosis. In addition, PTH treatment revealed a cytosolic staining pattern of 14-3-3. However, the significance of such differential localization for 14-3-3 function remains unknown. Taken together, the present study suggests that, PTH promotes the apoptosis of Caco-2 intestinal cells.