Background Dopamine exerts its effects mainly in nervous system through D1, D2 or D3 receptors. There are few reports dealing with the effects of dopamine on leukaemia cells. However, some dopamine agonists or antagonists do show biological effects on some types of leukaemia cells. Here, we report the effects of dopamine on the proliferation, differentiation and apoptosis of K562 leukaemia cells. Methods Proliferation was determined by MTT assay and cell counting both in liquid and semisolid cultures. Differentiation was verified by morphology, benzidine staining and flow cytometry. Apoptosis was checked by Hoechst 33258 staining and flow cytometry. The two groups were untreated group and treated group （dopamine 109 mol/L-104 mol/L）. Results In liquid culture, MTT assay and colony assay, dopamine inhibited proliferation of K562 cells. Inhibition rate was 29.28% at 106 mol/L and 36.10% at 10.5 mol/L after culture for 5 days in MTT assay. In benzidine staining and CD71 expression, dopamine induced K562 cells toward erythroid differentiation by increased 155% at 10^-6 mol/L and by 171% at 10^-5 mol/L after culture for 5 days in benzidine staining. In Hoechst 33258 staining and flow cytometry, dopamine induced K562 cells toward apoptosis. The sub G1 peak stained by PI was 14.23% at 104 mol/L dopamine after culture for 3 days compared with the control （0.81%） in flow cytometry. Conclusion Dopamine inhibites proliferation and induces both differentiation and apoptosis of K562 leukaemia cells.
