| Abstract: | We have found a relationship between sensitivity to glucocorticoid induced cell death (at 10 microM glucocorticoid) and ploidy in the human lymphoid cell line CCRF/CEM-C7. Most sensitive clones are diploid, whilst resistant clones and the resistant parent line CCRF/CEM are tetraploid. Diploid sensitive clones have a tendency to become aneuploid within a few months of isolation, with alterations in their kinetic responses to glucocorticoids. This is followed by a doubling in DNA content which results in reversion to the tetraploid glucocorticoid resistant state of the parent line CCRF/CEM. A few sensitive clones have been found to be tetraploid but with different kinetic responses to glucocorticoids as compared to diploid clones. The principal difference being an extended lag period (48-72 h) prior to lethal response. The relationship between ploidy and glucocorticoid sensitivity does not appear to extend to other human lymphoid cell lines. |
