The natural product mensacarcin induces mitochondrial toxicity and apoptosis in melanoma cells
The natural product mensacarcin induces mitochondrial toxicity and apoptosis in melanoma cells
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DOI：
10.1074/jbc.m116.774836
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发表时间：
2017-12-22
影响因子：
4.8
通讯作者：
Loesgen, Sandra
中科院分区：
文献类型：
--
作者：
Plitzko, Birte;Kaweesa, Elizabeth N.;Loesgen, Sandra
门sacarcin是一种高氧聚酮，最初是从土壤中的链霉菌细菌中分离出来的。它在美国国家癌症研究所(NCI)-60细胞系筛选的几乎所有细胞系中都表现出强大的细胞抑制特性（平均50%生长抑制= 0.2 μ M），对黑色素瘤细胞具有相对选择性的细胞毒性。此外，其与已知标准抗肿瘤药物的低比较相关性表明其具有独特的作用机制。治疗黑色素瘤的有效疗法是有限的，因此我们试图研究月经素独特的细胞抑制和细胞毒性作用及其作用方式。通过评估形态学和生化特征，我们证明了mensacarcin激活caspase-3/7依赖性凋亡途径并诱导黑色素瘤细胞死亡。经月经素暴露后，具有BRAFV600E突变的SK-Mel-28和SK-Mel-5黑色素瘤细胞表现出特征性的染色质浓缩以及明显的聚（adp -核糖）聚合酶-1切割。流式细胞术鉴定出大量凋亡的黑色素瘤细胞，单细胞电泳显示月经素导致遗传不稳定，这是早期细胞凋亡的标志。为了可视化月经素的亚细胞定位，我们合成了一种保留活性的月经素荧光探针。天然产物探针在处理后20分钟内定位到线粒体。活细胞生物能量通量分析证实，月经素能迅速扰乱能量产生和线粒体功能。荧光标记的月sacarcin的亚细胞定位及其在黑色素瘤细胞中不寻常的代谢作用提供了月sacarcin靶向线粒体的证据。Mensacarcin独特的作用模式表明，它可能是一种有用的探针，用于检查能量代谢，特别是在braf突变黑色素瘤中，并且代表了新的抗癌药物开发的有希望的线索。
Mensacarcin is a highly oxygenated polyketide that was first isolated from soil-dwelling Streptomyces bacteria. It exhibits potent cytostatic properties (mean of 50% growth inhibition = 0.2 mu M) in almost all cell lines of the National Cancer Institute (NCI)-60 cell line screen and relatively selective cytotoxicity against melanoma cells. Moreover, its low COMPARE correlations with known standard antitumor agents indicate a unique mechanism of action. Effective therapies for managing melanoma are limited, so we sought to investigate mensacarcin's unique cytostatic and cytotoxic effects and its mode of action. By assessing morphological and biochemical features, we demonstrated that mensacarcin activates caspase-3/7-dependent apoptotic pathways and induces cell death in melanoma cells. Upon mensacarcin exposure, SK-Mel-28 and SK-Mel-5 melanoma cells, which have the BRAFV600E mutation associated with drug resistance, showed characteristic chromatin condensation as well as distinct poly(ADP-ribose) polymerase-1 cleavage. Flow cytometry identified a large population of apoptotic melanoma cells, and single-cell electrophoresis indicated that mensacarcin causes genetic instability, a hallmark of early apoptosis. To visualize mensacarcin's subcellular localization, we synthesized a fluorescent mensacarcin probe that retained activity. The natural product probe was localized to mitochondria within 20 min of treatment. Live-cell bioenergetic flux analysis confirmed that mensacarcin disturbs energy production and mitochondrial function rapidly. The subcellular localization of the fluorescently labeled mensacarcin together with its unusual metabolic effects in melanoma cells provide evidence that mensacarcin targets mitochondria. Mensacarcin's unique mode of action suggests that it may be a useful probe for examining energy metabolism, particularly in BRAF-mutant melanoma, and represent a promising lead for the development of new anticancer drugs.