THE BETA-CORE FRAGMENT OF HUMAN CHORIONIC-GONADOTROPIN INHIBITS GROWTH OF KAPOSIS-SARCOMA-DERIVED CELLS AND A NEW IMMORTALIZED KAPOSIS-SARCOMA CELL-LINE

Objective: Kaposi's sarcoma (KS), a condition often associated with HI V infection, is more common in men than in women; pregnancy and sex ho rmones could be involved. Urinary human chorionic gonadrotrophin (hCG) has been reported to inhibit the growth of KS cell lines, with great variability among preparations. Urinary hCG often contains free forms of the hCG subunits and a fragment of the free beta-subunit, the beta- core, which may have biological activity. We compared the effect of th e beta-core fragment, the beta-subunit recombinant and urinary hCG on KS immortal and spindle cells. Design and methods: A new immortal KS c ell line was phenotypically and karyotypically characterized. The effe cts on growth of this cell line and of primary KS spindle cells by hCG and its purified derivatives were tested. induction of apoptosis was demonstrated using acridine orange/ethidium bromide staining. Results: The beta-core fragment harboured the most potent growth inhibitory ac tivity on a molar basis. After 72 h of treatment with the beta-core, 6 0-70% of KS cells show apoptotic nuclei. No effects were observed on e ndothelial cells. Conclusions: The beta-core fragment of hCG proved to be the most effective part of the hCG molecule, inducing growth inhib ition and apoptosis of KS cells. Thus, the beta-core could be the most appropriate hCG derivative for the therapy of KS.