| Popis: |
Receptors for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] have been described in several human breast cancer cell lines and more recently in human melanoma. The presence of 1,25-(OH)2D3 receptor (1,25-DR) in two cultured breast cancer cell lines was associated with receptors for calcitonin, another hormone thought to have effects on calcium handling. Therefore, it seemed important to examine a range of established human cancer cell lines for the presence of receptors for 1,25-(OH)2D3 and calcitonin. Thirty-three cancer cell lines were examined. 1,25-DR was found to be present in 23 lines, while calcitonin receptors were not detected in any of them. The 1,25-DR from several cell lines sedimented at about 3.5S in sucrose density gradients, had the appropriate specificity for vitamin D metabolites, had Kds of 0.8 to 2.2 x 10(-11) M, and had receptor concentrations of 12 to 99 fmol/mg protein. Ten malignant melanoma and nine colonic carcinoma lines constituted the largest groups of carcinoma cell lines, and seven and eight, respectively, of these were 1,25-DR positive. The high frequency of 1,25-DR positivity in the cultured colonic carcinoma cells is quite different from the low frequency of 1,25-DR in primary colonic carcinomas. It was also interesting that both of two cell lines derived from patients who had had both bone metastases and malignant hypercalcemia were 1,25-DR positive. These various cell lines may provide useful models for the examination of 1,25-(OH)2D3 action in vitro. |
