AIDS-associated Kaposi's sarcoma cells secrete a neurotrophic growth factor(s).

Here we treat neuronal cells with AIDS-Kaposi's sarcoma cell conditioned medium (A-KSCM) in order to determine if AIDS-Kaposi's sarcoma (A-KS) cells secrete neurotrophic factors. PC12 and NG108-15 cells were differentiated and allowed to form neuronal processes. Under these conditions and in the presence of A-KSCM, PC12 cells exhibited more than a twofold increase in the number of branches per process and a 40% increase in the number of processes per cell. For NG108-15 cells, A-KSCM treatment resulted in a three-fold increase in the number of branches per process and nearly a twofold increase in the number of processes per cell. A-KS cells secrete at least seven known growth factors; however, when tested, none of these growth factors mimicked the effect of A-KSCM on neuronal cell processes. Therefore A-KS cells secrete a neurotrophic factor(s) which remains to be identified and may play a critical role in the progression of A-KS.