Apoptotic events induced by a natural plastoquinone from marine algae Desmarestia menziesii on lymphoid neoplasms.

ABSTRACT New drugs development for lymphoid neoplasms treatment is an urgent necessity. The aim of this study was to evaluate the cytotoxic effect of the marine plastoquinone, 9’-hydroxysargaquinone (9’-HSQ), focusing on the investigation of its death mechanisms on lymphoid neoplastic cells. This particular plastoquinone reduced cell viability of different hematological tumor cell lines in a time-dependent and concentration-dependent manner. Intrinsic apoptosis occurred with time-dependent reduction of mitochondrial membrane potential (42.3 ± 1.1 % of Daudi and 18.6 ± 5.6 % of Jurkat cells maintained the mitochondrial membrane integrity) and AIF release (Daudi: 133.3 ± 8.1% and Jurkat: 125.7 ± 6.9%). Extrinsic apoptosis also took place, as demonstrated by an increased FasR expression (Daudi: 139.5 ± 7.1% and Jurkat: 126.0 ± 1.0%). A decrease in the expression of the Ki-67 proliferation marker (Daudi: 67.5 ± 2.5 % and Jurkat: 84.3 ± 3.8 %), survivin (Daudi: 66.0 ± 9.9% and Jurkat: 63.1 ± 6.0%) (Fig. 4B) and NF-κB expression (0.7 ± 0.04 in Jurkat cells) was observed. Finally, 9’-HSQ was cytotoxic against neoplastic cells from patients with different lymphoid neoplasms (CI50: 4.9 ± 0.6 to 34.2 ± 0.4 µM). These results provide new information about the apoptotic mechanisms of 9’-HSQ and suggest that it might be a promising alternative for the treatment of lymphoid neoplasms.