Transcriptional regulation of cytokine expression by diethyldithiocarbamate in human HL-60 promyelocytic leukemia cells

Diethyldithiocarbamate (DDTC) is an investigational agent used to ameliorate chemotherapy-or radiotherapy-induced myelosuppression. We studied the effects of DDTC on the regulation of hematopoietic cytokine production in human myeloid cells. The results demonstrated that DDTC decreases proliferation of human HL-60 promyelocytic leukemia cells in a concentration-dependent manner. DDTC treatment also increased interleukin-α- (IL-1α), IL-1β, and tumor necrosis factor (TNF) expression in these cells. Similar findings were obtained in normal human peripheral blood monocytes. Peak induction of these cytokines occurred 6–12 hr after exposure to DDTC; levels returned to those in control cells by 24–48 hr in HL-60 cells. This effect was specific for IL-1 and TNF in that there was no detectable increase in IL-3, macrophage colony-stimulating factor or granulocyte/macrophage colony-stimulating factor RNA expression. Transcriptional run-on analysis demonstrated that exposure to DDTC increased the rate of TNF gene transcription in HL-60 cells. These data suggest that the myeloprotective effects of DDTC may be mediated, at least in part, by the induction of TNF, IL-1α, and IL-1β.