In vitro sensitivity of Kaposi's sarcoma cells to various chemotherapeuticagents including acyclic nucleoside phosphonates

The involvement of a viral agent in the pathogenesis of Kaposi's sarcoma (K S) points to antiviral agents as possible therapeutic and/or prophylactic o ptions in the management of the disease. In the present study we investigat ed the antiproliferative effects of various chemotherapeutic agents, includ ing acyclic nucleoside phosphonates, on the growth of KS-derived cells. Nes ted PCR amplification demonstrated that these cells do not contain human he rpesvirus 8 (HHV-8) DNA sequences. The cytotoxicity of the chemotherapeutic compounds was less pronounced in KS cells than in human dermal microvascul ar endothelial cells, which are considered to be the normal counterpart of KS cells. Stimulation of KS cells with basic fibroblast growth factor (bFCF ) and correction of the IC, values by the doubling times revealed that the apparent chemotherapeutic resistance of KS cells could mainly be attributed to the long doubling times of these cells. bFCF-stimulated KS cells still exhibited no particular sensitivity to the acyclic nucleoside phosphonates whose activity extends to HHV-8, which is consistent with the absence of li near HHV-8 DNA synthesis in these cells. Our data suggest that neither anti -cancer agents nor antiviral agents such as the acyclic nucleoside phosphon ates can discriminate efficiently between KS cells and normal endothelial c ells.