Interleukin 8: An Autocrine Growth Factor for Human Ovarian Cancer

We determined whether interleukin-8 (IL-8) plays a direct role in the progressive growth of ovarian cancer cells by isolating high- and low-IL-8-producing clones from the parental Hey-A8 human ovarian cancer cell line and compared their proliferative activity and tumorigenicity in nude mice. The effect of exogenous IL-8 and mouse antihuman IL-8 neutralizing antibody on ovarian cancer cell proliferation was investigated. Finally, we studied the modulation of IL-8 production in ovarian cancer cells by sense and antisense IL-8 expression vector transfection and its effect on proliferation. The Hey-A8(H) clone was selected for its overexpression of IL-8. It has a significantly higher proliferation rate than the low-IL-8-producing clone, Hey-A8(L). Recombinant IL-8 (50 ng/ml) caused a significant increase in proliferation of Hey-A8(L) clones, and 10 μg/ml neutralizing antibody against IL-8 significantly decreased proliferative activity of both Hey-A8(H) and Hey-A8(L) clones. Enforced IL-8 expression by IL-8 expression vector transfection in Hey-A8(L) clones significantly increased tumor cell proliferation, microvessel density, and hence, tumorigenicity. We conclude that IL-8 has a direct and indirect growth-potentiating activity in human ovarian cancer cells.