Lithium inhibits terminal differentiation of erythroleukemia cells. Evidence for a pre-commitment 'priming' event

Cancer morbidity in psychiatric patients: influence of lithium carbonate treatment

The relationship between mental diseases and cancer development has been examined in a number of studies but the findings are still inconclusive and suffer from methodological problems. Studies conducted to examine the effect of lithium on malignant cells yielded inconsistent results. The study group included 609 patients treated by lithium carbonate and 2396 controls. A lower but non significant risk (RR = 0.79; CI = 0.17-3.60) to develop non-epithelial tumors was found among lithium carbonate treated psychiatric patients as compared to controls. A significantly (P = 0.05) inverse trend of cancer with lithium dose was observed. The risk of cancer development among each group of psychiatric patients was significantly lower than in the general population (RR = 0.68 for the lithium treated group versus 0.78 for controls). Mental patients have a lower cancer prevalence than the general population and lithium may have a protective effect.

Induction of the differentiation of HL-60 and WEHI-3B D+ leukemia cells by lithium chloride

The use of lithium chloride in manic-depressive patients and in patients receiving myelo-suppressive cancer chemotherapeutic agents is accompanied by a sustained leukocytosis due to an increase in granulocyte production. This property suggests that lithium chloride may have effects on hematopoietic differentiation. Treatment of cultured WEHI-3B D+ murine myelomonocytic and HL-60 human promyelocytic leukemia cells with millimolar concentrations of lithium chloride resulted in concentration-dependent increases in the number of differentiated myeloid cells, as determined by the ability of the cells to reduce nitroblue tetrazolium and by the binding of myeloid specific antibodies, and was associated with an inhibition of cellular proliferation. The effects of lithium chloride on growth and differentiation were antagonized by KCl, whereas NaCl had little effect. The induction of leukemic cell maturation by lithium chloride was markedly enhanced by the addition of low levels of retinoic acid. In contrast, other differentiation inducing agents (i.e. dimethyl sulfoxide and selenazofurin) had no effect on the degree of maturation induced by lithium. These findings suggest that the combination of lithium chloride and retinoic acid may have clinical utility in the treatment of leukemia through the induction of terminal differentiation.

Effects of lithium on dimethyl sulfoxide induced differentiation of HL-60 promyelocytic leukemia cells

The human promyelocytic leukemia cell line, HL-60, was used to investigate the effects of lithium on dimethyl sulfoxide (DMSO)-induced granulocytic differentiation of these cells. Dose-response studies showed an optimal increase of cellular proliferation when cells were incubated with 5 mM lithium for 5 days (127 +/- 5% of DMSO only treated cells). This enhancement in growth was preceded by significantly increased [methyl-3H]thymidine incorporation (143 +/- 4% of DMSO only treated controls) after 2 days. However, no significant changes in the ability of cells to reduce NBT could be detected irrespective of whether the cells were incubated with 1.25% (v/v) DMSO only, or with DMSO plus non-toxic concentrations (less than or equal to 10 mM) lithium. From the results obtained it would appear as if the arrest of growth induced by DMSO and the stimulation of proliferation effected by lithium occurs along independent pathways and that lithium exerts its mitogenic effect prior to the onset of terminal differentiation initiated by DMSO.