TGF beta and FGF-like growth factors involved in the pathogenesis of AIDS-associated Kaposi's sarcoma

Conditioned media from cell cultures derived from AIDS-associated Kaposi's sarcoma (KS) promote the growth of KS cells, fibroblasts and endothelial cells. Application of KS cells to the chicken chorion allantoic membrane induces neo-angiogenesis similar to that caused by fibroblast growth factors (FGF). Testing for known factors of the FGF family by Northern blotting does not reveal any difference from control fibroblasts negative for such an activity in their supernatants. This indicates secretion of an unknown FGF-like factor by KS cells possessing autocrine (KS cells) and paracrine (fibroblasts, endothelial cells) activity. It was reported that transforming growth factor-beta (TGF beta) is secreted by HIV-infected lymphocytes in AIDS patients. By testing this growth factor on KS cell cultures, growth-promoting activity was observed 5 to 20 times greater than that of the control value without TGF beta.