| 1. |
- Carrasco Del Amor, Ana Maria, et al.
(författare)
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Application of Bioactive Thermal Proteome Profiling to Decipher the Mechanism of Action of the Lipid Lowering 13(2)-Hydroxy-pheophytin Isolated from a Marine Cyanobacteria
- 2019
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Ingår i: Marine Drugs. - : MDPI. - 1660-3397. ; 17:6
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Tidskriftsartikel (refereegranskat)abstract
- The acceleration of the process of understanding the pharmacological application of new marine bioactive compounds requires identifying the compound protein targets leading the molecular mechanisms in a living cell. The thermal proteome profiling (TPP) methodology does not fulfill the requirements for its application to any bioactive compound lacking chemical and functional characterization. Here, we present a modified method that we called bTPP for bioactive thermal proteome profiling that guarantees target specificity from a soluble subproteome. We showed that the precipitation of the microsomal fraction before the thermal shift assay is crucial to accurately calculate the melting points of the protein targets. As a probe of concept, the protein targets of 13(2)-hydroxy-pheophytin, a compound previously isolated from a marine cyanobacteria for its lipid reducing activity, were analyzed on the hepatic cell line HepG2. Our improved method identified 9 protein targets out of 2500 proteins, including 3 targets (isocitrate dehydrogenase, aldehyde dehydrogenase, phosphoserine aminotransferase) that could be related to obesity and diabetes, as they are involved in the regulation of insulin sensitivity and energy metabolism. This study demonstrated that the bTPP method can accelerate the field of biodiscovery, revealing protein targets involved in mechanisms of action (MOA) connected with future applications of bioactive compounds.
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| 2. |
- Carrasco Del Amor, Ana Maria, et al.
(författare)
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Insights into the mechanism of action of the chlorophyll derivative 13-2-hydroxypheophytine a on reducing neutral lipid reserves in zebrafish larvae and mice adipocytes
- 2023
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Ingår i: European Journal of Pharmacology. - : ELSEVIER. - 0014-2999 .- 1879-0712. ; 960
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is a worldwide epidemic and natural products may hold promise in its treatment. The chlorophyll derivative 13-2-hydroxypheophytine (hpa) was isolated in a screen with zebrafish larvae to identify lipid reducing molecules from cyanobacteria. However, the mechanisms underlying the lipid-reducing effects of hpa in zebrafish larvae remain poorly understood. Thus, investigating the mechanism of action of hpa and validation in other model organisms such as mice represents important initial steps.In this study, we identified 14 protein targets of hpa in zebrafish larvae by thermal proteome profiling, and selected two targets (malate dehydrogenase and pyruvate kinase) involved in cellular metabolism for further validation by enzymatic measurements. Our findings revealed a dose-dependent inhibition of pyruvate kinase by hpa exposure using protein extracts of zebrafish larvae in vitro, and in exposure experiments from 3 to 5 days post fertilization in vivo. Analysis of untargeted metabolomics of zebrafish larvae detected 940 mass peaks (66 increased, 129 decreased) and revealed that hpa induced the formation of various phospholipid species (phosphoinositol, phosphoethanolamine, phosphatidic acid). Inter-species validation showed that brown adipocytes exposed to hpa significantly reduced the size of lipid droplets, increased maximal mitochondrial respiratory capacity, and the expression of PPARy during adipocyte differentiation.In line with our data, previous work described that reduced pyruvate kinase activity lowered hepatic lipid content via reduced pyruvate and citrate, and improved mitochondrial function via phospholipids. Thus, our data provide new insights into the molecular mechanism underlying the lipid reducing activities of hpa in zebrafish larvae, and species overlapping functions in reduction of lipids.
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| 3. |
- Ribeiro, Tiago, et al.
(författare)
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Cytotoxicity of portoamides in human cancer cells and analysis of the molecular mechanisms of action
- 2017
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- Portoamides are cyclic peptides produced and released by the cyanobacterial strain Phormidium sp. presumably to interfere with other organisms in their ecosystems (" allelopathy"). Portoamides were previously demonstrated to have an antiproliferative effect on human lung carcinoma cells, but the underlying mechanism of this activity has not been described. In the present work, the effects of portoamides on proliferation were examined in eight human cancer cell lines and two non-carcinogenic cell lines, and major differences in sensitivities were observed. To generate hypotheses with regard to molecular mechanisms of action, quantitative proteomics using 2D gel electrophoresis and MALDI-TOF/ TOF were performed on the colon carcinoma cell line HT-29. The expression of proteins involved in energy metabolism (mitochondrial respiratory chain and pentose phosphate pathway) was found to be affected. The hypothesis of altered energy metabolism was tested in further experiments. Exposure to portoamides resulted in reduced cellular ATP content, likely due to decreased mitochondrial energy production. Mitochondrial hyperpolarization and reduced mitochondrial reductive capacity was observed in treated cells. Furthermore, alterations in the expression of peroxiredoxins (PRDX4, PRDX6) and components of proteasome subunits (PSB4, PSA6) were observed in portoamide-treated cells, but these alterations were not associated with detectable increases in oxidative stress. We conclude that the cytotoxic activity of portoamides is associated with disturbance of energy metabolism, and alterations in mitochondrial structure and function.
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| 4. |
- Sousa, Maria Ligia, et al.
(författare)
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Antiproliferative Effects of the Natural Oxadiazine Nocuolin A Are Associated With Impairment of Mitochondrial Oxidative Phosphorylation
- 2019
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Ingår i: Frontiers in Oncology. - : FRONTIERS MEDIA SA. - 2234-943X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Natural products are interesting sources for drug discovery. The natural product oxadiazine Nocuolin A (NocA) was previously isolated from the cyanobacterial strain Nodularia sp. LEGE 06071 and here we examined its cytotoxic effects against different strains of the colon cancer cell line HCT116 and the immortalized epithelial cell line hTERT RPE-1. NocA was cytotoxic against colon cancer cells and immortalized cells under conditions of exponential growth but was only weakly active against non-proliferating immortalized cells. NocA induced apoptosis by mechanism(s) resistant to overexpression of BCL family members. Interestingly, NocA affected viability and induced apoptosis of HCT116 cells grown as multicellular spheroids. Analysis of transcriptome profiles did not match signatures to any known compounds in CMap but indicated stress responses and induction of cell starvation. Evidence for autophagy was observed, and a decrease in various mitochondrial respiration parameter within 1 h of treatment. These results are consistent with previous findings showing that nutritionally compromised cells in spheroids are sensitive to impairment of mitochondrial energy production due to limited metabolic plasticity. We conclude that the antiproliferative effects of NocA are associated with effects on mitochondrial oxidative phosphorylation.
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| 5. |
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| 6. |
- Sousa, Maria Ligia, et al.
(författare)
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Portoamides A and B are mitochondrial toxins and induce cytotoxicity on the proliferative cell layer of in vitro microtumours
- 2020
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Ingår i: Toxicon. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0041-0101 .- 1879-3150. ; 175, s. 49-56
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Tidskriftsartikel (refereegranskat)abstract
- Cyanobacteria are known to produce many toxins and other secondary metabolites. The study of their specific mode of action may reveal the biotechnological potential of such compounds. Portoamides A and B (PAB) are cyclic peptides isolated from the cyanobacteria Phormidium sp. due to their growth repression effect on microalgae and were shown to be cytotoxic against certain cancer cell lines. In the present work, viability was assessed on HCT116 colon cancer cells grown as monolayer culture and as multicellular spheroids (MTS), non-carcinogenic cells and on zebrafish larvae. HCT116 cells and epithelial RPE-1(hTERT) cells showed very similar degrees of sensitivities to PAB. PAB were able to penetrate the MTS, showing a four-fold high IC50 compared to monolayer cultures. The toxicity of PAB was similar at 4 degrees C and 37 degrees C suggesting energy-independent uptake. PAB exposure decreased ATP production, mitochondrial maximal respiration rates and induced mitochondrial membrane hyperpolarization. PAB induced general organelle stress response, indicated by an increase of the mitochondrial damage sensor PINK-1, and of phosphorylation of eIF2 alpha, characteristic for endoplasmic reticulum stress. In summary, these findings show general toxicity of PAB on immortalized cells, cancer cells and zebrafish embryos, likely due to mitochondrial toxicity.
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