Inhibition of melanoma growth by hemocyanin occurs via early apoptotic pathways.

ABSTRACT

BACKGROUND: We hypothesized that keyhole limpet hemocyanin (KLH) would reduce cellular proliferation and effect apoptosis of melanoma cell lines in vitro. METHODS: Two human melanoma cell lines (HTB68 and HTB72) were subjected to a dose-response treatment regimen of KLH (0.4 microg to 100 microg/well). Cell viability was tested by MTT assay (SIGMA, St Louis, MO) at 72 hours. Apoptosis and necrosis were measured by the Annexin V FITC assay (Biovision Inc, Mountain View, CA). RESULTS: Melanoma cell proliferation was significantly reduced in the HTB68 cell line treated with 6.3 microg or higher doses of KLH. A significant reduction in cell growth was also observed in the HTB72 cells at 50 and 100 microg of KLH. KLH increased early apoptotic activity, whereas both late apoptosis and necrosis were decreased by the addition of KLH. CONCLUSIONS: KLH significantly reduces cellular proliferation in vitro in melanoma, via early apoptotic pathways. The results warrant in vivo studies into the effects of KLH in melanoma.