Investigación

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Investigación contiene los documentos generados por los docentes e investigadores de la Universidad en su labor de investigación. Este depósito tiene como objetivos el almacenamiento, la gestión, la preservación y la difusión de estos documentos, y pretende contribuir al aumento de la visibilidad del trabajo desarrollado por los miembros de la comunidad universitaria.

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Now showing 1 - 20 of 75

Open Access
3,4,5-Trimethoxybenzoate of Catechin, an Anticarcinogenic Semisynthetic Catechin, Modulates the Physical Properties of Anionic Phospholipid Membranes
(MDPI, 2022-05-03) Aranda, Elisa; Teruel, José A.; Antonio Ortiz, Antonio; Pérez-Cárceles, María Dolores; Rodríguez-López, José N.; Aranda, Francisco J.; Bioquímica y Biología Molecular A
3,4,5-Trimethoxybenzoate of catechin (TMBC) is a semisynthetic catechin which shows strong antiproliferative activity against malignant melanoma cells. The amphiphilic nature of the molecule suggests that the membrane could be a potential site of action, hence the study of its inter action with lipid bilayers is mandatory in order to gain information on the effect of the catechin on the membrane properties and dynamics. Anionic phospholipids, though being minor components of the membrane, possess singular physical and biochemical properties that make them physiologically essential. Utilizing phosphatidylserine biomimetic membranes, we study the interaction between the catechin and anionic bilayers, bringing together a variety of experimental techniques and molecular dynamics simulation. The experimental data suggest that the molecule is embedded into the phos phatidylserine bilayers, where it perturbs the thermotropic gel to liquid crystalline phase transition. In the gel phase, the catechin promotes the formation of interdigitation, and in the liquid crystalline phase, it decreases the bilayer thickness and increases the hydrogen bonding pattern of the interfacial region of the bilayer. The simulation data agree with the experimental ones and indicate that the molecule is located in the interior of the anionic bilayer as monomer and small clusters reaching the carbonyl region of the phospholipid, where it also disturbs the intermolecular hydrogen bonding between neighboring lipids. Our observations suggest that the catechin incorporates well into phos phatidylserine bilayers, where it produces structural changes that could affect the functioning of the membrane
Open Access
A way to increase the bioaccesibility and photostability of roflumilast, a COPD treatment, by cyclodextrin monomers
(MDPI, 2019-04-30) Matencio, Adrián; Hernández García, Samanta; García Carmona, Francisco; López Nicolás, José Manuel; Bioquímica y Biología Molecular A
Roflumilast is an orally available inhibitor of phosphodiesterase (PDE) type 4, which is widely used in chronic obstructive pulmonary diseases. However, it has low solubility and adverse effects include diarrhea and nausea. Since its solubilization may improve treatment and, dismissing any adverse effects, its interaction with cyclodextrins (CDs) was studied. The Higuchi-Connors method was used to determine the complexation constant with different CDs, pH values and temperatures. Molecular docking was used to predict interaction between the complexes. An in vitro digestion experiment was carried out to test roflumilast protection. Finally, the photostability of the complex was evaluated. The complex formed with β-CD had the highest K11 value (646 ± 34 M−1), although this value decreased with increasing temperature. Similarly, K11 decreased as the pH increased. In vitro digestion showed that CDs protect the drug during digestion and even improve its bioaccessibility. Finally, CDs reduced the drug’s extreme photosensitivity, originating a fluorescence signal, which is described for first time. The kinetic parameters of the reaction were obtained. This study not only completes the complexation study of roflumilast-CD, but also points to the need to protect roflumilast from light, suggesting that tablets containing the drug might be reformulated.
Open Access
Acriflavine, a Potent Inhibitor of HIF-1α, Disturbs Glucose Metabolism and Suppresses ATF4-Protective Pathways in Melanoma under Non-Hypoxic Conditions
(MDPI, 2020-12-31) Martí Díaz, Román; Montenegro Arce, María Fernanda; Cabezas Herrera, Juan; Goding, Colin; Rodríguez López, José Neptuno; Sánchez del Campo Ferrer, Luis; Bioquímica y Biología Molecular A
Hypoxia-inducible factor (HIF)-1α is constitutively expressed in melanoma cells under normoxic conditions and its elevated expression correlates with the aggressiveness of melanoma tumors. Here, we used acriflavine, a potent inhibitor of HIF-1α dimerization, as a tool to investigate whether HIF-1α-regulated pathways contribute to the growth of melanoma cells under normoxia. We observed that acriflavine differentially modulated HIF-1α-regulated targets in melanoma under normoxic conditions, although acriflavine treatment resulted in over-expression of vascular endothelial growth factor (VEGF), its action clearly downregulated the expression of pyruvate dehydrogenase kinase 1 (PDK1), a well-known target of HIF-1α. Consequently, downregulation of PDK1 by acrifavine resulted in reduced glucose availability and suppression of the Warburg effect in melanoma cells. In addition, by inhibiting the AKT and RSK2 phosphorylation, acriflavine also avoided protective pathways necessary for survival under conditions of oxidative stress. Interestingly, we show that acriflavine targets activating transcription factor 4 (ATF4) for proteasomal degradation while suppressing the expression of microphthalmia-associated transcription factor (MITF), a master regulator of melanocyte development and a melanoma oncogene. Since acriflavine treatment results in the consistent death of melanoma cells, our results suggest that inhibition of HIF-1α function in melanoma could open new avenues for the treatment of this deadly disease regardless of the hypoxic condition of the tumor.
Open Access
Analysis of Dll4 regulation reveals a combinatorial rolefor Sox and Notch in arterial development
(National Academy of Sciences, 2013-07-01) Sacilotto, Natalia; Monteiro, Rui; Fritzsche, Martin; Becker, Philipp W.; Sánchez del Campo Ferrer, Luis; Liu, Ke; Pinheiro, Philip; Ratnayakaa, Indrika; Davies, Benjamin; Goding, Colin R.; Patient, Roger; Bou Gharios, George; De Val, Sarah; Bioquímica y Biología Molecular A
The mechanisms by which arterial fate is established and main-tained are not clearly understood. Although a number of signalingpathways and transcriptional regulators have been implicated inarterio-venous differentiation, none are essential for arterialformation, and the manner in which widely expressed factorsmay achieve arterial-speciﬁc gene regulation is unclear. Using bothmouse and zebraﬁsh models, we demonstrate here that arterialspeciﬁcation is regulated combinatorially by Notch signaling andSoxF transcription factors, via direct transcriptional gene activa-tion. Through the identiﬁcation and characterization of two arte-rial endothelial cell-speciﬁc gene enhancers for the Notch ligandDelta-like ligand 4 (Dll4), we show that arterial Dll4 expressionrequires the direct binding of both the RBPJ/Notch intracellulardomain and SOXF transcription factors. Speciﬁc combinatorial,but not individual, loss of SOXF and RBPJ DNA binding ablatesall Dll4 enhancer-transgene expression despite the presence ofmultiple functional ETS binding sites, as does knockdown of sox7;sox18 in combination with loss of Notch signaling. Furthermore,triple knockdown of sox7, sox18 and rbpj also results in ablationof endogenous dll4 expression. Fascinatingly, this combinatorialablation leads to a loss of arterial markers and the absence of a de-tectable dorsal aorta, demonstrating the essential roles of SoxF andNotch, together, in the acquisition of arterial identity
Open Access
Anticarcinogenic trimethoxybenzoate of catechin stabilizes the liquid crystalline bilayer phase in phosphatidylethanolamine membranes
(Elsevier, 2022-11-11) Aranda, Elisa; Teruel, José A.; Ortiz, Antonio; Pérez-Cárceles, María Dolores; Rodríguez-López, José N.; Aranda, Francisco J.; Bioquímica y Biología Molecular A
The anticarcinogenic properties of catechins stand out among the great variety of biological actions attributed to these compounds. The capacity of catechins to interact with lipids and their participation in membrane related processes points out to the membrane as their potential site of action. Phosphatidylethanolamine is an abundant phospholipid in mammalian membranes that has tendency to form non lamellar phases, it is associated with important cellular processes, and it has been related to cancer. In order to shed light into the molecular effect of the anticarcinogenic 3,4,5- trimethoxybenzoate of catechin (TMBC) on lipid polymorphism and membrane structure and dynamics, we present a combined experimental and computational study of the interaction between this semisyn thetic catechin and biomimetic membranes composed of unsaturated phosphatidylethanolamine. Our experimental evidence reveals that TMBC is readily incorporated into unsaturated phos phatidylethanolamine system where it is able to shift the gel to liquid crystalline phase transition tem perature to lower values, decreasing the cooperativity and the enthalpy change of the transition. The presence of TMBC is able to promote the formation of gel phase immiscibility and to block the formation of the inverted hexagonal phase. In the bilayer liquid crystalline phase, the catechin decreases the inter lamellar repeat distance, it increases the fluidity of the membrane, and it alters the hydrogen bond pat tern of the interfacial region of the bilayer. Our molecular dynamics results concur with the experimental data and locate TMBC forming different domains near the interfacial region of the bilayer where it mod ifies the lateral pressure profile of the membrane leading to a stabilization of the bilayer in the liquid crystalline phase and to a potential alteration of the function of the membrane
Open Access
Antitumoral drug potential of tryptophan betaxanthin and related plant betalains in the Caenorhabditis elegans tumoral model
(MDPI, 2020-07-22) Henarejos Escudero, Paula; Hernández García, Samanta; Guerrero Rubio, M. Alejandra; García Carmona, Francisco; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
Betalains are plants pigments identified as potent antioxidant molecules, naturally present in foods like beetroot and prickly pears. Although activities described for betalain-containing formulations include cancer prevention and treatment, the use of extracts instead of purified pigments has avoided the investigation of the real chemopreventive and chemotherapeutic potential of these phytochemicals. Three betalain-rich extracts and six individual pure betalains were used in this work to characterize the activity and to explore possible molecular mechanisms. The animal model Caenorhabditis elegans (tumoral strain JK1466) was used to evaluate the effect of betalains as chemotherapeutics drugs. An objective evaluation method of tumor growth in C. elegans has been developed to assess the possible antitumoral activity of the different treatments. This protocol allowed a fast and reliable screening of possible antitumoral drugs. Among the betalains tested, tryptophan-betaxanthin reduced tumor size by 56.4% and prolonged the animal’s lifespan by 9.3%, indicating high effectiveness and low toxicity. Structure–activity relationships are considered. Assays with mutant strains of C. elegans showed that the mechanism underlying these effects was the modulation of the DAF-16 transcription factor and the insulin signaling pathway. Our results indicate that tryptophan-betaxanthin and related betalains are strong candidates as antitumoral molecules in cancer treatment.
Restricted
Applications of cyclodextrins in food science. A Review
(Elsevier, 2020-08-25) Matencio, Adrián; Navarro Orcajada, Silvia; García Carmona, Francisco; López Nicolás, José Manuel; Bioquímica y Biología Molecular A
Background: The food industry is constantly attempting to develop better products that will have a positive effect on health (commonly known as functional foods). In this respect, cyclodextrins (CDs) could be of interest because they are tasteless, non-caloric and odourless molecules with several valuable characteristics, such as a capacity to separate chiral compounds and solubilize or stabilize bioactive compounds (BaC). Scope and approach: This review represents a revision of the state-of-the-art of CDs and their uses in the food industry. Key findings and conclusions: We analysed their metabolism and regulatory aspects of current applications of CDs: as carriers, for removing components, to produce or extract BaC, their use as nanosensors or in food packaging. We study how inclusion complexed are formed referring to the most common techniques and parameters Moreover, how inclusion complexes are formed will be studied with reference to the most common techniques and parameters. In conclusion, their applications in the food and other industries will increase in the coming years without a doubt.
Embargo
Applications of cyclodextrins in food science. A review
(Elsevier, 2020-08-25) Matencio, Adrián; Navarro Orcajada, Silvia; García Carmona, Francisco; López Nicolás, José Manuel; Bioquímica y Biología Molecular A
Background: The food industry is constantly attempting to develop better products that will have a positive effect on health (commonly known as functional foods). In this respect, cyclodextrins (CDs) could be of interest because they are tasteless, non-caloric and odourless molecules with several valuable characteristics, such as a capacity to separate chiral compounds and solubilize or stabilize bioactive compounds (BaC). Scope and approach: This review represents a revision of the state-of-the-art of CDs and their uses in the food industry. Key findings and conclusions: We analysed their metabolism and regulatory aspects of current applications of CDs: as carriers, for removing components, to produce or extract BaC, their use as nanosensors or in food packaging. We study how inclusion complexed are formed referring to the most common techniques and parameters Moreover, how inclusion complexes are formed will be studied with reference to the most common techniques and parameters. In conclusion, their applications in the food and other industries will increase in the coming years without a doubt.
Open Access
Are seven amino acid substitutions sufﬁcient to explain the evolution of high L-DOPA 4,5-dioxygenase activity leading to betalain pigmentation? Revisiting the gain-of-function mutants of Bean et al. (2018)
(Wiley, 2023-05-27) Guerrero-Rubio, M. Alejandra; Walker-Hale, Nathanael; Guo, Rui; Sheehan, Hester; Timoneda, Alfonso; Gandía Herrero, Fernando; Brockington, Samuel F.; Bioquímica y Biología Molecular A
This work revisits a publication by Bean et al. (2018) that reports seven amino acid substitu-tions are essential for the evolution of L-DOPA 4,5-dioxygenase (DODA) activity in Caryo-phyllales. In this study, we explore several concerns which led us to replicate the analyses of Bean et al. (2018). Our comparative analyses, with structural modelling, implicate numerous residues addi-tional to those identiﬁed by Bean et al. (2018), with many of these additional residues occur-ring around the active site of BvDODAα1. We therefore replicated the analyses of Bean et al.(2018) to re-observe the effect of their original seven residue substitutions in a BvDODAα2 background, that is the BvDODAα2-mut3 variant. Multiple in vivo assays, in both Saccharomyces cerevisiae and Nicotiana benthamiana,did not result in visible DODA activity in BvDODAα2-mut3, with betalain production always10-fold below BvDODAα1. In vitro assays also revealed substantial differences in both cataly-tic activity and pH optima between BvDODAα1, BvDODAα2 and BvDODAα2-mut3 proteins,explaining their differing performance in vivo. In summary, we were unable to replicate the in vivo analyses of Bean et al. (2018), and our quantitative in vivo and in vitro analyses suggest a minimal effect of these seven residues inaltering catalytic activity of BvDODAα2. We conclude that the evolutionary pathway to high DODA activity is substantially more complex than implied by Bean et al. (2018)
Embargo
Betalain health-promoting effects after ingestion in Caenorhabditis elegans are mediated by DAF-16/FOXO and SKN-1/Nrf2 transcription factors
(Elsevier, 2020-06-05) Guerrero Rubio, M. Alejandra; Hernández García, Samanta; Escribano, Josefa; Jiménez Atiénzar, Mercedes; Cabanes, Juana; García Carmona, Francisco; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
Betalain-rich extracts have been used for many years by their nutraceutical potential. However, the study of their bioactivities has always been hampered by their difficult obtention. To explain their mode of action, seventeen pure betalains were tested in vivo using the animal model C. elegans. Four betalains, named indicaxanthin, indoline carboxylic acid-betacyanin, phenylalanine-betaxanthin, and dopaxanthin, behaved as extraordinary in vivo antioxidants and anti-aging compounds, by increasing the lifespan of C. elegans up to 16.82%, 16.65%, 16.53%, and 12.93%, respectively. The first microarrays performed with betalains and biological confirmation with different mutant strains showed that this life extension is due to a reduction of oxidative stress and the activation of the transcription factors DAF-16/FOXO and SKN-1/Nrf2. They are involved in longevity and oxidative stress resistance pathways and lead to overexpression of HSPs genes, involved in resistance to cancer and Alzheimer's, opening novel research lines in the search for effective plant-based treatments.
Open Access
Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase
(MDPI, 2009-12-18) Sánchez del Campo Ferrer, Luis; Sáez Ayala, Magalí; Chazarra Parres, Soledad; Cabezas Herrera, Juan; Rodríguez López, José Neptuno; Bioquímica y Biología Molecular A
Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of DHFR with dissociation constants (K-D) of 0.9 and 1.8 mu M, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (-)-epigallocatechin (EGC) and (-)-epicatechin (EC)] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl)(-)-epicatechin; TMECG), which effectively binds to DHFR (K-D = 2.1 mu M). In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a K-D of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a K-D of 0.6 mu M. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy.
Open Access
BRN2 is a non-canonical melanoma tumor-suppressor
(Springer Nature, 2021-06-17) Hamm, Michael; Sohier, Pierre; Petit, Valérie; Raymond, Jérémy H.; Delmas, Véronique; Le Coz, Madeleine; Gesbert, Franck; Kenny, Colin; Aktary, Zackie; Pouteaux, Marie; Rambow, Florian; Sarasin, Alain; Charoenchon, Nisamanee; Bellacosa, Alfonso; Sanchez del Campo Ferrer, Luis; Mosteo, Laura; Lauss, Martin; Meijer, Dies; Steingrimsson, Eirikur; Jönsson, Göran B.; Cornell, Robert; Davidson, Irwin; Goding, Colin R.; Larue, Lionel; Bioquímica y Biología Molecular A
While the major drivers of melanoma initiation, including activation of NRAS/BRAF and loss of PTEN or CDKN2A, have been identified, the role of key transcription factors that impose altered transcriptional states in response to deregulated signaling is not well understood. The POU domain transcription factor BRN2 is a key regulator of melanoma invasion, yet its role in melanoma initiation remains unknown. Here, in a BrafV600E PtenF/+ context, we show that BRN2 haplo-insufficiency promotes melanoma initiation and metastasis. However, metastatic colonization is less efficient in the absence of Brn2. Mechanistically, BRN2 directly induces PTEN expression and in consequence represses PI3K signaling. Moreover, MITF, a BRN2 target, represses PTEN transcription. Collectively, our results suggest that on a PTEN heterozygous background somatic deletion of one BRN2 allele and temporal regulation of the other allele elicits melanoma initiation and progression
Open Access
Characterization of betalain-loaded liposomes and its bioactive potential in vivo after ingestion
(Elsevier, 2022-12-09) Martínez-Rodriguez, Pedro; Guerrero-Rubio, M.Alejandra; Hernández García, Samanta; Henarejos Escudero, Paula; García Carmona, Francisco; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
Betalains are plant pigments characterized by showing a wide range of beneficial properties for health. Its bioactive potential has been studied for the first time after its encapsulation in liposomes and subsequent administration to the animal model Caenorhabditis elegans. Phenylalanine-betaxanthin and indoline carboxylic acid-betacyanin encapsulated at concentrations of 25 and 500 μM managed to reduce lipid accumulation and oxidative stress in the nematodes. Highly antioxidant betalains dopaxanthin and betanidin were also included in the survival analyses. The results showed that phenylalanine-betaxanthin was the most effective betalain by increasing the lifespan of C. elegans by 21.8%. In addition, the administration of encapsulated natural betanidin increased the nematodes’ survival rate by up to 13.8%. The preservation of the bioactive properties of betalains manifested in this study means that the stabilization of the plant pigments through encapsulation in liposomes can be postulated as a new way for administration in pharmacological and food applications.
Embargo
Characterization of recombinant Beta vulgaris 4,5-DOPA-extradiol-dioxygenase active in the biosynthesis of betalains
(2012-01-24) Gandía-Herrero, Fernando; García-Carmona, Francisco; Bioquímica y Biología Molecular A
Betalains are water-soluble pigments with high antiradical capacity which bestow bright colors to flowers, fruits and other parts of most plants of the order Caryophyllales. The formation of the structural unit of all betalains, betalamic acid from the precursor amino acid 4,5-dihydroxyphenylalanine is catalyzed by the enzyme 4,5-DOPAextradiol-dioxygenase followed by intramolecular cyclization of the 4,5-secodopa intermediate. This paper describes the purification and the molecular and functional characterization of an active 4,5-DOPA-extradiol-dioxygenase from the best-known source of betalains—Beta vulgaris—after heterologous expression in Escherichia coli. The enzyme is a monomeric protein with a molecular mass of 32 kDa characterized by chromatography, electrophoresis and MALDITOF analysis. Enzyme kinetic properties are characterized in the production of betalamic acid, the structural, chromophoric and bioactive unit of plant pigment betalains.
Open Access
Comparison of a Pair of Synthetic Tea-Catechin-Derived Epimers: Synthesis, Antifolate Activity, and Tyrosinase-Mediated Activation in Melanoma
(WILEY, 2011-03-07) Sáez Ayala, Magalí; Sánchez del Campo Ferrer, Luis; Montenegro Arce, María Fernanda; Chazarra Parres, Soledad; Tárraga Tomás, Alberto; Cabezas Herrera, Juan; Rodríguez López, José Neptuno; Bioquímica y Biología Molecular A
Despite bioavailability issues, tea catechins have emerged as promising chemopreventive agents because of their efficacy in various animal models. We synthesized two catechin-derived compounds, 3-O-(3,4,5-trimethoxybenzoyl)-(-)-catechin (TMCG) and 3-O-(3,4,5-trimethoxybenzoyl)-(-)-epicatechin (TMECG), in an attempt to improve the stability and cellular absorption of tea polyphenols. The antiproliferative and pro-apoptotic activities of both compounds were analyzed with various cancer cell systems, and TMCG, which was easily synthesized in excellent yield, was more active than TMECG in both melanoma and non-melanoma cell lines. TMCG was also a better inhibitor of dihydrofolate reductase and was more efficiently oxidized by tyrosinase, potentially explaining the difference in activity between these epimers.
Open Access
Consumption of commonly used artificial food dyes increases activity and oxidative stress in the animal model Caenorhabditis elegans
(Elsevier, 2023-05-02) Guerrero Rubio, M. Alejandra; Hernández García, Samanta; García-Carmona, Francisco; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
In recent decades, the consumption of artificial colorants in foods and beverages has increased despite of concerns in the general population raised by studies that have shown possible injurious effects. In this study, tartrazine, sunset yellow, quinoline yellow, ponceau 4R, carmoisine and allura red were employed as pure compounds to explore their effects in vivo in the animal model Caenorhabditis elegans. The exposition of C. elegans to these artificial dyes produced damage related with aging such as oxidative stress and lipofuscin accumulation, as well as a heavy shortening of lifespan, alterations in movement patterns and alterations in the production of dopamine receptors. Besides, microarray analysis performed with worms treated with tartrazine and ponceau 4R showed how the consumption of synthetic colorants is able to alter the expression of genes involved in resistance to oxidative stress and neurodegeneration.
Open Access
Design, synthesis and gene modulation insights into pigments derived from tryptophan-betaxanthin, which act against tumor development in Caenorhabditis elegans
(MDPI, 2023-12-20) Henarejos Escudero, Paula; Méndez-García, Fernando F.; Hernández García, Samanta; Martínez Rodríguez, Pedro; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
The use of betalains, which are nitrogenous plant pigments, by the food industry is widespread and reflects their safety after intake. The recent research showed outstanding results for L-tryptophan-betaxanthin, a phytochemical present in traditional Chinese medicine, as an antitumoral agent when the activity was evaluated in the animal model Caenorhabditis elegans. Thus, L-tryptophanbetaxanthin is now presented as a lead compound, from which eleven novel structurally related betaxanthins have been designed, biotechnologically produced, purified, and characterized. The antitumoral effect of the derived compounds was evaluated on the JK1466 tumoral strain of C. elegans. All the tested molecules significantly reduced the tumoral gonad sizes in a range between 31.4% and 43.0%. Among the novel compounds synthesized, tryptophan methyl ester-betaxanthin and tryptophan benzyl ester-betaxanthin, which are the first betalains to contain an ester group in their structures, caused tumor size reductions of 43.0% and 42.6%, respectively, after administration to the model animal. Since these were the two most effective molecules, their mechanism of action was investigated by microarray analysis. Differential gene expression analysis showed that tryptophan methyl ester-betaxanthin and tryptophan benzyl ester-betaxanthin were able to down-regulate the key genes of the mTOR pathway, such as daf-15 and rict-1.
Open Access
Digestive glands extraction and precise pigment analysis support the exclusion of the carnivorous plant Dionaea muscipula Ellis from the Caryophyllales order
(2018-09) Henarejos Escudero, Paula; Guadarrama-Flores, Berenice; García-Carmona, Francisco; Gandía Herrero, Fernando; Bioquímica y Biología Molecular A
In the order Caryophyllales, plants synthesize betalains instead of anthocyanins, with only two exceptions, the Caryophyllaceae and Molluginaceae. Dionaea muscipula Ellis was included in the Caryophyllales order but recent research based on genetic studies proposed the consideration of the Droseraceae family into the Nepenthales order. In this work we face the dilemma of the phylogenetic classification of Dionaea from a phytochemical point of view. Dionaea’s pigments were analyzed by using techniques of structural analysis. Extracts from the leaves, mature stem and flowers of different specimens of Dionaea were analyzed, to find possible differences in the types of pigments or in their proportion in different parts of the plant. These extracts were analyzed by spectrophotometry, HPLC co-elution and ESI-MS/MS. In addition, digestive glands were extracted from the snap trap with minor sample manipulation and by reducing the non-pigmented plant tissue. Considering only the digestive glands instead of whole snap traps, the analyses allowed to quantitate and elucidate the structure of the compounds responsible for the red coloration: delphinidin-3-O-glucoside (myrtillin), cyanidin-3-O-glucoside (kuromanin) and a third compound, the aglycone cyanidin, detected in the species for the first time. The unambiguous results of the present work support the exclusion of Dionaea from the Caryophyllales.
Open Access
Directed Phenotype Switching as an Effective Antimelanoma Strategy
(Cell Press, 2013-06-20) Sáez Ayala, Magalí; Montenegro Arce, María Fernanda; Sánchez del Campo Ferrer, Luis; Fernández Pérez, María Piedad; Chazarra Parres, Soledad; Freter, Rasmus; Middleton, Mark; Piñero Madrona, Antonio; Cabezas Herrera, Juan; Goding, Colin R.; Rodríguez López, Jose Neptuno; Bioquímica y Biología Molecular A; Cirugía, Pediatría y Obstetricia y Ginecología
Therapeutic resistance in melanoma and other cancers arises via irreversible genetic, and dynamic phenotypic, heterogeneity. Here, we use directed phenotype switching in melanoma to sensitize melanoma cells to lineage-specific therapy. We show that methotrexate (MTX) induces microphthalmia-associated transcription factor (MITF) expression to inhibit invasiveness and promote differentiation-associated expression of the melanocyte-specific Tyrosinase gene. Consequently, MTX sensitizes melanomas to a tyrosinase-processed antifolate prodrug 3-O-(3,4,5-trimethoxybenzoyl)-(−)-epicatechin (TMECG), that inhibits the essential enzyme DHFR with high affinity. The combination of MTX and TMECG leads to depletion of thymidine pools, double-strand DNA breaks, and highly efficient E2F1-mediated apoptosis in culture and in vivo. Importantly, this drug combination delivers an effective and tissue-restricted antimelanoma therapy in vitro and in vivo irrespective of BRAF, MEK, or p53 status.
Open Access
Distinctive physiological and molecular responses to cold stress among cold-tolerant and cold-sensitive Pinus halepensis seed sources
(BMC, 2018) Taibi, Khaled; Campo, Antonio D. del; Vilagrosa, Alberto; Bellés, José María; López Gresa, M.P.; López Nicolás, José Manuel; Mulet, José M.; Bioquímica y Biología Molecular A
Background: Forest species ranges are confined by environmental limitations such as cold stress. The natural range shifts of pine forests due to climate change and proactive-assisted population migration may each be constrained by the ability of pine species to tolerate low temperatures, especially in northern latitudes or in high altitudes. The aim of this study is to characterize the response of cold-tolerant versus cold-sensitive Pinus halepensis (P. halepensis) seedlings at the physiological and the molecular level under controlled cold conditions to identify distinctive features which allow us to explain the phenotypic difference. With this objective gas-exchange and water potential was determined and the photosynthetic pigments, soluble sugars, glutathione and free amino acids content were measured in seedlings of different provenances under control and cold stress conditions. Results: Glucose and fructose content can be highlighted as a potential distinctive trait for cold-tolerant P. halepensis seedlings. At the amino acid level, there was a significant increase and accumulation of glutathione, proline, glutamic acid, histidine, arginine and tryptophan along with a significant decrease of glycine. Conclusion: Our results established that the main difference between cold-tolerant and cold-sensitive seedlings of P. halepensis is the ability to accumulate the antioxidant glutathione and osmolytes such as glucose and fructose, proline and arginine.