Koulman A, Proksch P, Ebel R, Beekman A C, van Uden W, Konings A W, Pedersen J A, Pras N, Woerdenbag H J
Department of Pharmaceutical Biology, Groningen Institute for Drug Studies (GIDS), University of Groningen, The Netherlands.
J Nat Prod. 1996 Jun;59(6):591-4. doi: 10.1021/np960167z.
Aeroplysinin-1 (1) and the structurally related dienone 2 were cytotoxic to Ehrlich ascites tumor (EAT) cells and HeLa tumor cells in the microculture tetrazolium (MTT) and clonogenic assays. Both compounds are bromotyrosine derivatives, isolated from the marine spong Aplysina aerophoba. As the effective concentrations in the MTT assay were lower than in the clonogenic assay, 1 and 2 are able to cause growth inhibition as well as actual cell death in these cell lines. With an IC50 value of 8.2 microM (MTT assay, 2-h incubation, EAT cells), 1 was the more toxic compound. When the cells were depleted of glutathione by pretreatment with buthionine sulfoximine, they were significantly more sensitive toward 1 and 2 in the MTT assay. A dose-enhancement factor as high as 11.8 was found in EAT cells after 2-h incubation with 2. Using electron paramagnetic resonance we were able to measure free radical formation of 1 and 2, yielding the semiquinone structures 3 and 4, respectively, in a culture medium with tumor cells. It is concluded that free radicals are, at least in part, responsible for the cytotoxicity of 1 and 2. This conclusion is in line with expectations derived from the chemical structures of both compounds.
气单胞菌素-1（1）和结构相关的二烯酮2在微量培养四唑盐（MTT）和克隆形成试验中对艾氏腹水瘤（EAT）细胞和人宫颈癌HeLa细胞具有细胞毒性。这两种化合物都是从海洋海绵嗜气海绵中分离出来的溴酪氨酸衍生物。由于MTT试验中的有效浓度低于克隆形成试验中的有效浓度，1和2能够在这些细胞系中引起生长抑制以及实际的细胞死亡。1的IC50值为8.2微摩尔（MTT试验，2小时孵育，EAT细胞），是毒性更强的化合物。当用丁硫氨酸亚砜胺预处理使细胞内谷胱甘肽耗尽时，它们在MTT试验中对1和2的敏感性显著增加。在与2孵育2小时后，EAT细胞中发现高达11.8的剂量增强因子。利用电子顺磁共振，我们能够测量1和2的自由基形成，在含有肿瘤细胞的培养基中分别产生半醌结构3和4。得出的结论是，自由基至少部分地导致了1和2的细胞毒性。这一结论与从这两种化合物的化学结构得出的预期一致。
