The mitochondrion has emerged as a promising therapeutic target for novel cancer treatments because of its essential role in tumorigenesis and resistance to chemotherapy. Previously, we described a natural compound, 10-((2,5-dihydroxybenzoyl)oxy)decyl) triphenylphosphonium bromide (GA-TPP+C10), with a hydroquinone scaffold that selectively targets the mitochondria of breast cancer (BC) cells by binding to the triphenylphosphonium group as a chemical chaperone; however, the mechanism of action remains unclear. In this work, we showed that GA-TPP+C10 causes time-dependent complex inhibition of the mitochondrial bioenergetics of BC cells, characterized by (1) an initial phase of mitochondrial uptake with an uncoupling effect of oxidative phosphorylation, as previously reported, (2) inhibition of Complex I-dependent respiration, and (3) a late phase of mitochondrial accumulation with inhibition of α-ketoglutarate dehydrogenase complex (αKGDHC) activity. These events led to cell cycle arrest in the G1 phase and cell death at 24 and 48 h of exposure, and the cells were rescued by the addition of the cell-penetrating metabolic intermediates l-aspartic acid β-methyl ester (mAsp) and dimethyl α-ketoglutarate (dm-KG). In addition, this unexpected blocking of mitochondrial function triggered metabolic remodeling toward glycolysis, AMPK activation, increased expression of proliferator-activated receptor gamma coactivator 1-alpha (pgc1α) and electron transport chain (ETC) component-related genes encoded by mitochondrial DNA and downregulation of the uncoupling proteins ucp3 and ucp4, suggesting an AMPK-dependent prosurvival adaptive response in cancer cells. Consistent with this finding, we showed that inhibition of mitochondrial translation with doxycycline, a broad-spectrum antibiotic that inhibits the 28 S subunit of the mitochondrial ribosome, in the presence of GA-TPP+C10 significantly reduces the mt-CO1 and VDAC protein levels and the FCCP-stimulated maximal electron flux and promotes selective and synergistic cytotoxic effects on BC cells at 24 h of treatment. Based on our results, we propose that this combined strategy based on blockage of the adaptive response induced by mitochondrial bioenergetic inhibition may have therapeutic relevance in BC.
- MeSH
- apoptóza účinky léků MeSH
- doxycyklin farmakologie MeSH
- gentisáty chemie farmakologie MeSH
- heterocyklické sloučeniny chemie farmakologie MeSH
- ketoglutarátdehydrogenasový komplex antagonisté a inhibitory genetika MeSH
- lidé MeSH
- mitochondrie účinky léků patologie MeSH
- nádory prsu farmakoterapie genetika patologie MeSH
- organofosforové sloučeniny chemie farmakologie MeSH
- oxidativní fosforylace účinky léků MeSH
- proliferace buněk účinky léků MeSH
- proteinkinasy genetika MeSH
- proteosyntéza účinky léků MeSH
- protinádorové látky farmakologie MeSH
- ribozomy účinky léků MeSH
- synergismus léků MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ischemic and reperfusion injury is a serious condition related to numerous biochemical and electrical abnormalities of the myocardium. It has been repeatedly studied in various animal models. In this study, the production of hydroxyl radicals and electrophysiological parameters were compared in three species. Rat, guinea pig and rabbit isolated hearts were perfused according to Langendorff under strictly identical conditions. The heart rate and arrhythmia were monitored during ischemia and reperfusion periods at defined time intervals; the production of hydroxyl radical was determined by HPLC as 2.5-dihydroxybenzoic acid (2.5-DHBA) formed by salicylic acid hydroxylation. Relationship between arrhythmias and production of 2.5-DHBA was studied. The inter-species differences were observed in timing of arrhythmias onset and their severity, and in the production of 2.5-DHBA in both ischemia and reperfusion. The most considerable changes were observed in rats, where arrhythmias appeared early and with highest severity during ischemia on one side and the regular rhythm was restored early and completely during reperfusion. The corresponding changes in the production of 2.5-DHBA were observed. It can be concluded that rat isolated heart is the most suitable model for evaluation of ischemia/reperfusion injury under given experimental conditions.
- MeSH
- elektrokardiografie metody MeSH
- gentisáty metabolismus MeSH
- hydroxylový radikál metabolismus MeSH
- králíci MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- morčata MeSH
- potkani Wistar MeSH
- reperfuzní poškození myokardu komplikace patofyziologie MeSH
- srdeční arytmie etiologie patofyziologie MeSH
- srdeční frekvence MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- morčata MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Some time ago, we published an announcement that the azo group that closes model cyclic peptides is often reduced in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) in the presence of 2,5-dihydroxybenzoic acid (2,5-DHB) as the matrix. In this work, we demonstrate that these peptides are ionized in all DHB matrix isomers, although threshold ionization laser energies as well as the reduction ratios differ in each matrix. Using a NALDI plate, we confirmed that their reduction depends on the presence of DHB matrix and that the hydrogen atoms participating in the reaction come from the DHB matrix hydroxyl group. We show that the reduction ratio is affected by the overall covalent structure of the peptide, by the presence of a free carboxyl group in DHB matrix, by the mutual position of the hydroxyl and carboxyl groups, as well as the laser beam intensity. Based on these results, it can be concluded that the azo-group reduction in cyclic peptides is a very complex process and we are far from fully understanding its nature. We hope that our experimental results will help to shed some light on the MALDI process that still remains mysterious in some of its aspects.
- MeSH
- azosloučeniny chemie metabolismus MeSH
- cyklické peptidy chemie metabolismus MeSH
- gentisáty chemie MeSH
- hydroxylový radikál chemie MeSH
- isomerie MeSH
- oxidace-redukce MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
