meso-Methyl BODIPY photocages stand out for their absorption properties and easy chromophore derivatization. However, their low uncaging efficiencies often hinder applications requiring release of protected substrates in high amounts. In this study, we demonstrate that the sulfonothioated BODIPY group photocleaves a sulfonylthio group from the meso-methyl position with a 10-fold higher quantum yield than the most efficient leaving groups studied to date. Photocleavage, observed in solution and in cells, is accompanied by the spatiotemporally controlled photorelease of H2Sn. For this reason, sulfonothioated BODIPY may be applied in cell signaling, redox homeostasis, and metabolic regulation studies.
- MeSH
- signální transdukce * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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 Cu2+ in phosphate buffer (pH 7), and in two breast cancer cell lines. EPR, UV-Vis and fluorescence spectroscopy showed that WL and Cu2+ build a coordination complex with 2 : 1 stoichiometry and distorted tetrahedral geometry. WL showed strong fluorescence that was quenched by Cu2+. 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 Cu2+ 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 Cu2+ 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.
- MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza MeSH
- komplexní sloučeniny metabolismus MeSH
- kumariny farmakologie MeSH
- lidé MeSH
- měď metabolismus MeSH
- nádorové buňky kultivované MeSH
- nádory prsu farmakoterapie metabolismus patologie MeSH
- subcelulární frakce metabolismus MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Wedelolactone is a multi-target natural plant coumestan exhibiting cytotoxicity towards cancer cells. Although several molecular targets of wedelolactone have been recognized, the molecular mechanism of its cytotoxicity has not yet been elucidated. In this study, we show that wedelolactone acts as an inhibitor of chymotrypsin-like, trypsin-like, and caspase-like activities of proteasome in breast cancer cells. The proteasome inhibitory effect of wedelolactone was documented by (i) reduced cleavage of fluorogenic proteasome substrates; (ii) accumulation of polyubiquitinated proteins and proteins with rapid turnover in tumor cells; and (iii) molecular docking of wedelolactone into the active sites of proteasome catalytic subunits. Inhibition of proteasome by wedelolactone was independent on its ability to induce reactive oxygen species production by redox cycling with copper ions, suggesting that wedelolactone acts as copper-independent proteasome inhibitor. We conclude that the cytotoxicity of wedelolactone to breast cancer cells is partially mediated by targeting proteasomal protein degradation pathway. Understanding the structural basis for inhibitory mode of wedelolactone might help to open up new avenues for design of novel compounds efficiently inhibiting cancer cells.
- MeSH
- inhibitory proteasomu chemie farmakologie toxicita MeSH
- kumariny chemie farmakologie toxicita MeSH
- lidé MeSH
- měď metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory prsu metabolismus MeSH
- proteasomový endopeptidasový komplex chemie metabolismus MeSH
- proteolýza MeSH
- reaktivní formy kyslíku metabolismus MeSH
- simulace molekulového dockingu MeSH
- ubikvitinace MeSH
- vazba proteinů MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
