Interleukin-6 stimulates cell migration, invasion and integrin expression in HTR-8/SVneo cell line.

Interleukin-6 (IL-6) is present in human endometrium throughout menstrual cycle and in pregnancy. Trophoblast also expresses IL-6. IL-6R and its associated signal transducer gp130 were found in trophoblast as well. IL-6 is generally assumed to be relevant for trophoblast invasion. This study was undertaken to determine influence of endogenous and externally added IL-6 on invasion and migration of first trimester of pregnancy trophoblast in vitro. Integrins alpha(5)beta(1) and alpha(1)beta(1) have been shown to play an important role in trophoblast invasion and the effect of IL-6 on the expression of these integrin subunits was studied. We are showing that in both isolated first trimester of pregnancy cytotrophoblast (CTB) and HTR-8/SVneo cell line IL-6 and IL-6R are present. The effect on migration was studied using cell wounding and migration test on HTR-8/SVneo cells. Effect of IL-6 and function blocking anti-IL-6 antibody in Matrigel invasion tests was studied on both cell types. The effect of IL-6 on integrin subunit expression was determined by cell-based ELISA and Western blot on HTR-8/SVneo cells. The results obtained show that exogenous IL-6 has stimulatory effect on cell migration in HTR-8/SVneo and invasion by both cell types. Function blocking anti-IL-6 inhibited unstimulated invasion by isolated first trimester cytotrophoblast and both cell migration and invasion in unstimulated HTR-8/SVneo. Integrin alpha(5) expression was stimulated by IL-6 to 134% (p<0.05), alpha(1) to 135% (p<0.005), and beta(1) to 134% (p<0.001) of control in cell-based ELISA, but also in Western blot. The data obtained show for the first time sensitivity of extravillous trophoblast cell line HTR-8/SVneo to IL-6, in addition to isolated first trimester cytotrophoblast. We conclude that both exogenous and endogenous IL-6 stimulate trophoblast cell migration and invasion, which may be partly attributable to stimulation of expression of the studied integrin subunits.