Interleukin 8 is an autocrine growth factor and a surrogate marker for Kaposi's sarcoma

Kaposi's sarcoma (KS) is the most common tumor associated with HIV-1 infection. Here, we report the expression, regulation, and biological effect of interleukin (IL)-8 in KS. AIDS-KS cell lines expressed higher levels of IL-8 than either human umbilical vein endothelial cells (HUVECs), human aortic smooth muscle (AoSM) cells or fibroblast cells (T1). The inflammatory cytokine IL-1beta up-regulated IL-8 expression in a time- and concentration-dependent manner in KS cell lines. IL-8 antisense oligonucleotides specifically reduced IL-8 mRNA and protein levels and inhibited KS cell growth in a dose-dependent manner. In addition, supernatant from a KS cell line induced the growth of HUVECs and angiogenesis in chicken chorioallantoic membrane assays, both of which were inhibited by IL-8 neutralizing antibody. Serum levels of IL-8 were also elevated in KS cases compared with matched controls. Modulation of IL-8 may thus be of therapeutic value in this disease.