Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization
| Authors | |
|---|---|
| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | Metallomics |
| MU Faculty or unit | |
| Citation | |
| Web | https://pubs.rsc.org/en/Content/ArticleLanding/2018/MT/C8MT00191J#!divAbstract |
| Doi | http://dx.doi.org/10.1039/c8mt00191j |
| Keywords | Breast cancer; copper; lysosome; redox interactions; wedelolactone |
| Description | Wedelactone (WL), a plant polyphenolic derivative of coumestan, represents a promising anti-cancer agent. The underlying mechanisms of its action are not fully understood and appear to involve interplay with copper ions. Herein, we examined coordination and redox interactions of WL with copper ions in phosphate buffer (pH 7), and in two breast cancer cell lines. EPR, UV-Vis and fluorescence spectroscopy showed that WL and copper ions build a coordination complex and distorted tetrahedral geometry. WL showed strong fluorescence that was quenched by copper ions. The sequestration of the intracellular copper pool with neocuproine led to a significant drop in the cytotoxic effects of WL, whereas the co-application of copper ions and WL and the formation of an extracellular complex suppressed both the cytotoxic effects of WL and copper loading. Fluorescence microscopy showed that WL is mainly localized in the cytosol and significantly less in the nuclei. WL fluorescence was stronger in cells pretreated with neocuproine, implying that the complex of WL and copper ions is formed inside the cells. WL caused a two-fold increase in the lysosomal level of copper as well as copper-dependent lysosome membrane permeabilization. On the other hand, the protective effects of overexpression of thioredoxin 1 imply that WL exerts the main oxidative impact inside the nucleus. The interactions of WL with copper may be essential for therapeutic performance and selectivity against cancer cells, taking into account that a number of cancer types, including breast cancer, exhibit increased intratumoral copper levels or altered copper distribution. |
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