Modulation of leukaemia blast colony growth by steroid hormones

The effect of steroid hormones on in vitro colony growth of human myelogenous leukaemia cells was examined. beta-Oestradiol, testosterone and 5-beta-dihydrotesterone had little effect on HL60 promyelocytic leukaemia cells of blast colony forming cells (CFC) from eight patients with acute non-lymphocytic leukaemia (ANLL). These compounds inhibited blast colony growth at very high concentrations (10(-6)-10(-4) M). In contrast, hydrocortisone (HC) had highly variable effects on blast colony growth. HL60 cells were resistant to HC at concentrations up to 10(-4) M but blast CFC showed a wide range of response. Some patients were resistant to HC at all concentrations treated, while others were inhibited by concentrations as low as 10(-8) M. The inhibitory effect of HC was also observed on 3H-TdR incorporation by stimulated peripheral blood blasts. Inhibition by HC was not blocked by progesterone, suggesting this effect was not mediated by specific hormone receptors. These data indicate differences in the response of blast cells in ANLL and normal progenitors to steroid hormones. Cells from patients with ANLL display variable inhibition by HC which is probably not mediated by specific receptors.