Búsqueda selectiva de fármacos en la flora vascular andaluza que interfieran con el proceso de destoxificación celular, eficaces como coadyuvantes en la terapia antitumoral

Resumen del trabajo presentado a la 1ª Jornada de los másteres de biotecnología de la UPO, celebrada en Sevilla el 3 de mayo de 2012.El objetivo principal del tratamiento quimioterapico es conseguir la muerte de la célula tumoral. Para ello es necesario que la mayor cantidad de fármaco activo posible llegue a su diana molecular en el interior de la célula, si embargo, muchos pacientes desarrollan resistencia al tratamiento farmacológico. Cuando la resistencia farmacológica surge a fármacos no relacionados ni químicamente, ni por mecanismo de acción, se le llama resistencia a múltiples fármacos (MDR, Multi-Drug Resistance) (Dexter and Leith, 1986). Estos paciente tienen una capacidad normal para captar los fármacos, pero sus células tumorales sobre-expresan transportadores de membrana que los eliminan o destoxifican (Gottesman, 2002). Nuestro objetivo en este proyecto es la búsqueda de inhibidores de las bombas destoxificadoras que puedan ser usados como coadyuvantes en la terapia anti-tumoral. El descubrimiento de nuevos fármacos requiere de estrategias de escrutinios biológicos y de una fuente de principios activos. En nuestro laboratorio hemos desarrollado un bio-indicador de destoxificación celular basado en la levadura Schizosaccharomyces pombe. En esta levadura los mecanismos de destoxificación son muy similares a los que presentan las células humanas y dependen de los mismos transportadores. Usando este bio-indicador, estamos realizando ensayos sistemáticos de nuevos principios activos extraídos de la flora vascular andaluza.Peer reviewe

Búsqueda selectiva de fármacos en la flora vascular andaluza que interfieran con el proceso de destoxificación celular, eficaces como coadyuvantes en la terapia antitumoral

El objetivo principal del tratamiento quimioterapico es conseguir la muerte de la célula tumoral. Para ello es necesario que la mayor cantidad de fármaco activo posible llegue a su diana molecular en el interior de la célula, si embargo, muchos pacientes desarrollan resistencia al tratamiento farmacológico. Cuando la resistencia farmacológica surge a fármacos no relacionados ni químicamente, ni por mecanismo de acción, se le llama resistencia a múltiples fármacos (MDR, Multi-Drug Resistance) (Dexter and Leith, 1986). Estos paciente tienen una capacidad normal para captar los fármacos, pero sus células tumorales sobre-expresan transportadores de membrana que los eliminan o destoxifican (Gottesman, 2002). Nuestro objetivo en este proyecto es la búsqueda de inhibidores de las bombas destoxificadoras que puedan ser usados como coadyuvantes en la terapia anti-tumoral. El descubrimiento de nuevos fármacos requiere de estrategias de escrutinios biológicos y de una fuente de principios activos. En nuestro laboratorio hemos desarrollado un bio-indicador de destoxificación celular basado en la levadura Schizosaccharomyces pombe. En esta levadura los mecanismos de destoxificación son muy similares a los que presentan las células humanas y dependen de los mismos transportadores. Usando este bio-indicador, estamos realizando ensayos sistemáticos de nuevos principios activos extraídos de la flora vascular andaluza.Dexter, D. L. and Leith, J. T. (1986). Tumor heterogeneity and drug resistance. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 4, 244-57.Gottesman, M. M. (2002). Mechanisms of cancer drug resistance. Annual review of medicine 53, 615-27

Screening for natural anticancer agents using a fission yeast bioassay

A fission-yeast bioassay guided screening on several plant extracts is carried out to search for anticancer agents, and an extract from leaves of Corema album (L.) D. Don (Ericaceae) is found to have antiproliferative activity. Further fractionation afforded 2′,4′-dihydroxychalcone (DHC) as the main cytotoxic compound present in the extract. Our detailed biological analysis shows that antiproliferative activity of this flavonoid is likely due to its ability to induce DNA damage which blocks cell cycle progression.This work was supported by grants to RRD from the Spanish Ministry for Science and Innovation (Ministerio de Ciencia e Inovación) BFU2010-21310 and from La Junta de AndaluciaP09-CTS-4697 (PROYECTO DE EXCELENCIA). MAS-P was supported by a fellowship from El Consejo Andaluz de Colegios Oficiales de Farmacéuticos. AJ L-G was supported by a FPU fellowship from the Spanish Ministry for Science and Innovation (Ministerio de Ciencia e Inovación).Peer Reviewe

Yeast as a biosensor of detoxification: A tool for identifying new compounds that revert multidrug resistance

During tumour progression, cells accumulate secondary mutations and/or chromosomal aberrations that generate genetic diversity within the tumour cell population. This may result in the acquisition of new properties that increase tumour malignancy, such as invasiveness or resistance to chemotherapy. One of the important mechanisms of chemotherapy resistance is overexpression or biochemical activation of ABC family transporters. ABC transporters remove antitumour drugs from the cell, reducing their intracellular concentration and producing resistance against a wide range of chemically unrelated drugs, known as multidrug resistant phenotype (MDR). During recent decades, much effort has been devoted to the isolation of compounds able to inhibit the activity of these transporters. However, few such compounds have reached clinical practice and MDR remains a serious complication in cancer therapy. In an innovative approach to finding new ABC inhibitors, we propose using fission yeast Schizosaccharomyces pombe as a biosensor of detoxification that would enable cost-efficient screening of natural compounds and chemical libraries for molecules that revert the MDR phenotype. Existing fission yeast tools provide genetic, biochemical and cell biological analysis, thereby facilitating identification of drug targets. Putative inhibitors and modulators of ABC transporters could be used in combination with chemotherapeutic drugs for the treatment of multidrug resistant tumours.Peer reviewe

Gut Microbiota as a Potential Predictive Biomarker in Relapsing-Remitting Multiple Sclerosis

Background: The influence of the microbiome on neurological diseases has been studied for years. Recent findings have shown a different composition of gut microbiota detected in patients with multiple sclerosis (MS). The role of this dysbiosis is still unknown. Objective: We analyzed the gut microbiota of 15 patients with active relapsing-remitting multiple sclerosis (RRMS), comparing with diet-matched healthy controls. Method: To determine the composition of the gut microbiota, we performed high-throughput sequencing of the 16S ribosomal RNA gene. The specific amplified sequences were in the V3 and V4 regions of the 16S ribosomal RNA gene. Results: The gut microbiota of RRMS patients differed from healthy controls in the levels of the Lachnospiraceae, Ezakiella, Ruminococcaceae, Hungatella, Roseburia, Clostridium, Shuttleworthia, Poephyromonas, and Bilophila genera. All these genera were included in a logistic regression analysis to determine the sensitivity and the specificity of the test. Finally, the ROC (receiver operating characteristic) and AUC with a 95% CI were calculated and best-matched for Ezakiella (AUC of 75.0 and CI from 60.6 to 89.4) and Bilophila (AUC of 70.2 and CI from 50.1 to 90.4). Conclusions: There is a dysbiosis in the gut microbiota of RRMS patients. An analysis of the components of the microbiota suggests the role of some genera as a predictive factor of RRMS prognosis and diagnosis

Pseudomonas aeruginosa antibiotic susceptibility profiles, genomic epidemiology and resistance mechanisms: a nation-wide five-year time lapse analysisResearch in context

Summary: Background: Pseudomonas aeruginosa healthcare-associated infections are one of the top antimicrobial resistance threats world-wide. In order to analyze the current trends, we performed a Spanish nation-wide high-resolution analysis of the susceptibility profiles, the genomic epidemiology and the resistome of P. aeruginosa over a five-year time lapse. Methods: A total of 3.180 nonduplicated P. aeruginosa clinical isolates from two Spanish nation-wide surveys performed in October 2017 and 2022 were analyzed. MICs of 13 antipseudomonals were determined by ISO-EUCAST. Multidrug resistance (MDR)/extensively drug resistance (XDR)/difficult to treat resistance (DTR)/pandrug resistance (PDR) profiles were defined following established criteria. All XDR/DTR isolates were subjected to whole genome sequencing (WGS). Findings: A decrease in resistance to all tested antibiotics, including older and newer antimicrobials, was observed in 2022 vs 2017. Likewise, a major reduction of XDR (15.2% vs 5.9%) and DTR (4.2 vs 2.1%) profiles was evidenced, and even more patent among ICU isolates [XDR (26.0% vs 6.0%) and DTR (8.9% vs 2.6%)] (p < 0.001). The prevalence of Extended-spectrum β-lactamase/carbapenemase production was slightly lower in 2022 (2.1%. vs 3.1%, p = 0.064). However, there was a significant increase in the proportion of carbapenemase production among carbapenem-resistant strains (29.4% vs 18.1%, p = 0.0246). While ST175 was still the most frequent clone among XDR, a slight reduction in its prevalence was noted (35.9% vs 45.5%, p = 0.106) as opposed to ST235 which increased significantly (24.3% vs 12.3%, p = 0.0062). Interpretation: While the generalized decrease in P. aeruginosa resistance, linked to a major reduction in the prevalence of XDR strains, is encouraging, the negative counterpart is the increase in the proportion of XDR strains producing carbapenemases, associated to the significant advance of the concerning world-wide disseminated hypervirulent high-risk clone ST235. Continued high-resolution surveillance, integrating phenotypic and genomic data, is necessary for understanding resistance trends and analyzing the impact of national plans on antimicrobial resistance. Funding: MSD and the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea—NextGenerationEU