Influence of leukotrienes on in vitro growth of human mammary carcinoma cell line MCF-7

Objectives: The aim of this work was to study the action of leukotrienes on the growth of human mammary cancer cells MCF-7. Study design: The growth of the cells was measured by incorporation of H-3-thymidine. The action of leukotriene (LT)B4, LTD4, LTC4, LTE4 or arachidonate (AA) was tested in human mammary cancer cells MCF-7 in vitro. Results: LTB4 or LTD4 but not LTC4 or LTE4 reduced significant incorporation of H-3-thymidine in MCF-7 cells up to 52% or 56% respectively, when administered in concentrations 0.1-1000 pM. Agents in concentrations of 0.01 pM or 10 000 pM did not effect 3H-thymidine incorporation. We have shown, that MCF-7 cells synthesise LTB4 when treated with calcium ionophor A23187 (10 mu M). Leukotriene-antagonist LY171883 (10 mu M) lifts inhibitory effects of LTB4 or LTD4. Arachidonic acid (10 mu M) inhibits 3H-thymidine incorporation up to 72%. 5-lipoxygenase inhibitor MK-886 (100 nM) lifts the inhibitory effect of arachidonate. Conclusions: LTB4 or LTD4 inhibits MCF-7 breast cancer cell growth. LT-receptors mediate the growth-inhibitory effect of LTB4 or LTD4. (C) 1998 Elsevier Science Ireland Ltd.