Fucoxanthin and its deacetylated product, fucoxanthinol, induce apoptosis of primary effusion lymphomas.

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin's lymphoma caused by human herpesvirus 8. Conventional chemotherapy has limited effect on PEL, and the prognosis is poor. Carotenoids are a family of natural pigments and have several biological functions. We evaluated the anti-PEL effects of carotenoid, fucoxanthin (FX) and its metabolite, fucoxanthinol (FXOH). Treatment of PEL cells with FX or FXOH induced cell cycle arrest during G₁ phase and caspase-dependent apoptosis. FX and FXOH treatment silenced NF-κB, AP-1 and Akt activation, in conjunction with down-regulation of anti-apoptotic proteins and cell cycle regulators. Importantly, proteasome degradation was responsible for the low levels of proteins after FXOH treatment. In animal studies, treatment with FX reduced the growth of PEL-cell tumors. The results provide the rationale for future clinical use of FX and FXOH for the treatment of PEL.