Androgen-independent prostate cancer cells circumvent EGFR inhibition by overexpression of alternative HER receptors and ligands

et al.The deregulation of the epidermal growth factor receptor (EGFR) pathway plays a major role in the pathogenesis of prostate cancer (PCa). However, therapies targeting EGFR have demonstrated limited effectiveness in PCa. A potential mechanism to overcome EGFR blockade in cancer cells is the autocrine activation of alternative receptors of the human EGFR (HER) family through the overexpression of the HER receptors and ligands. In the present study, we were interested in analyzing if this intrinsic resistance mechanism might contribute to the inefficacy of EGFR inhibitors in PCa. To this end, we selected two androgen-independent human prostate carcinoma cell lines (DU145 and PC3) and established DU145 erlotinib-resistant cells (DUErR). Cells were treated with three EGFR inhibitors (cetuximab, gefinitib and erlotinib) and the sensitivity to each treatment was assessed. The gene expression of the four EGFR/HER receptors and seven ligands of the HER family was analyzed by real-time PCR prior to and after each treatment. The receptors expression and activation were further characterized by flow cytometry and western blot analysis. EGFR inhibition rapidly induced enhanced gene expression of the EGF, betacellulin and neuregulin-1 ligands along with HER2, HER3 and HER4 receptors in the DU145 cells. In contrast, slight changes were observed in the PC3 cells, which are defective in the phosphatase and tensin homolog (PTEN) tumor suppressor gene. In the erlotinib-resistant DUErR cells, the expression of HER2 and HER3 was increased at mRNA and protein levels together with neuregulin-1, leading to enhanced HER3 phosphorylation and the activation of the downstream PI3K/Akt survival pathway. HER3 blockage by a monoclonal antibody restored the cytostatic activity of erlotinib in DUErR cells. Our results confirm that the overexpression and autocrine activation of HER3 play a key role in mediating the resistance to EGFR inhibitors in androgen-independent PCa cells.We acknowledge the Instituto de Salud Carlos III (grants RD06/0020/0041, RD06/0020/0028), Universitat de Girona (grant PUG2007A/10) and Generalitat de Catalunya (grant 2009SGR208) for providing funding for this project. D.C.S. and C.P. acknowledge their fellowships from Ministerio de Educación y Ciencia (grant AP2007-01953) and Universitat de Girona (grant BR08/19), respectivelyPeer Reviewe

Síntesi de pèptids relacionats amb la seqüència RGD : estudi comparatiu de la seva incorporació a la superfície de liposomes carregats amb 5-fur

Tesi de Llicenciatura per a la obtenció del Grau de Farmàcia. Facultat de Farmàcia. Universitat de Barcelona. Director: Francisca Reig Isart, Ma. Asunción Alsina Esteller. 1997

Contribució de la P-selectina en els processos inflamatoris

[cat] La P-selectina és una molècula d'adhesió que mitjança la interacció de les cèl·lules endotelials i plaquetes activades amb els leucòcits. Desenvolupa un paper determinant en la resposta inflamatòria, ja que possibilita l'adhesió inicial dels leucòcits circulants a l'endoteli activat, generant un rodament deis leucòcits sobre la paret vascular que és clau per la posterior migració i acumulació deis leucòcits als lIocs de lesió, on desenvolupen la seva resposta immunològica. La P-selectina també participa en la trombogènesi, promovent la interacció entre els leucòcits i les plaquetes, de manera que afavoreix la incorporació dels leucòcits als trombes en formació i la seva activació. La P-selectina juga un paper important en diversos models inflamatoris experimentals i s'ha vist que la seva inhibició, bé mitjançant anticossos que bloquegen la seva funció o generant animals genèticament deficients en la proteïna, millora l'evolució de la inflamació. Per tant, el bloqueig de la P-selectina en humans podria tenir un elevat potencial terapèutic. Però abans és important definir amb precisió la seva funció específica en el desenvolupament de respostes inflamatòries concretes, de cara a avaluar l’eficàcia del seu bloqueig com a tractament en desordres inflamatoris. És per això que l'objectiu general de la present tesi és caracteritzar la contribució de la P-selectina als processos inflamatoris

A green light-triggerable RGD peptide for photocontrolled targeted drug delivery: synthesis and photolysis studies

We describe for the first time the synthesis and photochemical properties of a coumarin-caged cyclic RGD peptide and demonstrate that uncaging can be efficiently performed with biologically compatible green light. This was accomplished by using a new dicyanocoumarin derivative (DEAdcCE) for the protection of the carboxyl function at the side chain of the aspartic acid residue, which was selected on the basis of Fmoc-tBu SPPS compatibility and photolysis efficiency. The shielding effect of a methyl group incorporated in the coumarin derivative near the ester bond linking both moieties in combination with the use of acidic additives such as HOBt or Oxyma during the basic Fmoc-removal treatment were found to be very effective for minimizing aspartimide-related side reactions. In addition, a conjugate between the dicyanocoumarin-caged cyclic RGD peptide and ruthenocene, which was selected as a metallodrug model cargo, has been synthesized and characterized. The fact that green-light triggered photoactivation can be efficiently performed both with the caged peptide and with its ruthenocenoyl bioconjugate reveals great potential for DEAdcCE-caged peptide sequences as selective drug carriers in the context of photocontrolled targeted anticancer strategies

Grafismo, cultura de proyecto gráfico y creación de identidad visual en manifestaciones espontáneas en Barcelona y Cataluña : comparación de tres acontecimientos históricos: Boicot a los tranvías (1951), Marxa de la llibertat (1976) y No a la guerra (2003)

Comunicació presentada a la conferència anual de la Fundació Història del Disseny, celebrada el 2011 a Barcelona.Las manifestaciones son una de las formas más habituales de activismo. Se trata de actos de comunicación, generalmente multitudinarios y ejercidos en el ámbito público, que parten de una necesidad de dar a conocer el acuerdo o desacuerdo respecto a una idea para promover un cambio. Requieren, de una parte, de un esfuerzo organizativo y, del otro, de una concepción del elemento a comunicar que se concreta en soportes gráficos, generando una identidad visual ya sea de forma involuntaria o consciente. Estas manifestaciones se caracterizan por ser organizadas y llevadas a cabo por grupos de individuos sin un necesario conocimiento o preparación en el ámbito de la cultura visual o el diseño gráfico. Sin embargo, consiguen resolver las necesidades gráficas con los recursos técnicos disponibles de una manera efectiva. El boicot de tranvías del 1 de marzo de 1951 en Barcelona, la Marxa de la Llibertat (marcha por la libertad}, durante el verano de 1976 en diferentes poblaciones de Cataluña, y la manifestación multitudinaria del "No a la guerra" de 2003, también en Barcelona, constituyen tres ejemplos históricos en los que la población se organizó de forma más o menos espontánea a favor de la lucha por la igualdad, la libertad y/o la paz. El objetivo de este artículo es el de identificar y establecer posibles tendencias en cuanto al conocimiento, asimilación y uso de técnicas gráficas, creación de identidad visual o gestión del proyecto gráfico por parte de la población civil, a través del análisis de los mensajes visuales creados por estos agentes, tanto en lo referente a las técnicas gráficas utilizadas, como por el contenido de los mismos, junto con el estudio de las estrategias comunicativas diseñadas para lograr el éxito de las convocatorias. A continuación se presentan los tres acontecimientos analizados, incidiendo los elementos identitarios más destacables para posteriormente comentar, a partir de semejanzas y diferencias, las conclusiones

Solid-phase approaches for labelling targeting peptides with far-red emitting coumarin fluorophores

Fluorophores based on organic molecules hold great potential for ligand-targeted imaging applications, particularly those operating in the optical window in biological tissues. In this work, we have developed three straightforward solid-phase approaches based on amide-bond formation or a Cu(I)-catalyzed azide-alkyne click (CuAAC) reaction for labeling an octreotide peptide with far-red emitting coumarin-based COUPY dyes. First, the conjugatable versions of COUPY fluorophores incorporating the required functional groups (e.g., carboxylic acid, azide, or alkyne) were synthesized and characterized. All of them were found fully compatible with Fmoc/tBu solid-phase peptide synthesis, which allowed for the labeling of octreotide either through amide-bond formation or by CuAAC reaction. A near quantitative conversion was obtained after only 1 h of reaction at RT when using CuSO4 and sodium ascorbate independently of the click chemistry approach used (azido-COUPY/alkynyl-peptide resin or alkynyl-COUPY/azido-peptide resin). COUPY-octreotide conjugates were found stable in cell culture medium as well as noncytotoxic in HeLa cells, and their spectroscopic and photophysical properties were found similar to those of their parent coumarin dyes. Finally, the potential bioimaging applications of COUPY-octreotide conjugates were demonstrated by confocal microscopy through the visualization of living HeLa cells overexpressing the somatostatin subtype-2 receptor

An integrin-targeted photoactivatable Pt(IV) complex as a selective anticancer pro-drug: synthesis and photoactivation studies

A new anticancer agent based on the conjugation of a photoactivatable Pt(IV) pro-drug to a cyclic RGD-containing peptide is described. Upon visible light irradiation, phototoxicity was induced preferentially in SK-MEL-28 melanoma cancer cells overexpressing alphaVbeta3 integrin compared to control DU-145 human prostate carcinoma cells

Synthetic lethal interaction of cetuximab with MEK1/2 inhibition in NRAS-mutant metastatic colorectal cancer

KRAS mutations are an established predictor of lack of response to EGFR-targeted therapies in patients with metastatic colorectal cancer (mCRC). However, little is known about the role of the rarer NRAS mutations as a mechanism of primary resistance to the anti-EGFR monoclonal antibody cetuximab in wild-type KRAS mCRC. Using isogenic mCRC cells with a heterozygous knock-in of the NRAS activating mutation Q61K, we aimed to elucidate the mechanism(s) by which mutant NRAS blocks cetuximab from inhibiting mCRC growth. NRASQ61K/+ cells were refractory to cetuximab-induced growth inhibition. Pathway-oriented proteome profiling revealed that cetuximab-unresponsive ERK1/2 phosphorylation was the sole biomarker distinguishing cetuximab-refractory NRASQ61K/+ from cetuximab-sensitive NRAS+/+ cells. We therefore employed four representative MEK1/2 inhibitors (binimetinib, trametinib, selumetinib, and pimasertib) to evaluate the therapeutic value of MEK/ERK signaling in cetuximab-refractory NRAS mutation-induced mCRC. Co-treatment with an ineffective dose of cetuximab augmented, up to more than 1,300-fold, the cytotoxic effects of pimasertib against NRASQ61K/+ cells. Simultaneous combination of MEK1/2 inhibitors with cetuximab resulted in extremely high and dose-dependent synthetic lethal effects, which were executed, at least in part, by exacerbated apoptotic cell death. Dynamic monitoring of real-time cell growth rates confirmed that cetuximab synergistically sensitized NRASQ61K/+ cellsto MEK1/2 inhibition. Our discovery of a synthetic lethal interaction of cetuximab in combination with MEK1/2 inhibition for the NRAS mutant subgroup of mCRC underscores the importance of therapeutic intervention both in the MEK-ERK and EGFR pathways to achieve maximal therapeutic efficacy against NRAS-mutant mCRC tumors

Disseny d'un sistema d'indicadors ambientals en camins i diagnosi socioambiental del Camí de Cavalls : sector sud-oest

Menorca va ser declarada Reserva de la Biosfera per la UNESCO l'any 1993. Entre d'altres, un dels aspectes més emblemàtics de l'Illa és el Camí de Cavalls. Preservar la diversitat que aquest ofereix comporta una gestió complexa. Per això, és necessària per una millor gestió ambiental la realització prèvia d'una diagnosi per determinar en quina situació es troba actualment el Camí, i així poder optimitzar els mecanismes de gestió de l'espai. Aquesta diagnosi té com a objectius desenvolupar un sistema d'indicadors ambientals i socioeconòmics i validar-los per avaluar els canvis que es poden donar en el litoral de Menorca en els propers anys en relació a aquest espai. Dins d'aquest marc de treball, el sistema d'indicadors dissenyat a nivell teòric ha estat validat a través d'un exhaustiu treball de camp. Amb aquest objectiu s'ha volgut crear un disseny eficient, de forma que qualsevol persona que vulgui aplicar-lo al Camí de Cavalls o en altres tipologies de camí pugui fer-ho d'una manera correcte.Nota: Aquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia.Aquest projecte està relacionat amb el titulat "Disseny d'un sistema d'indicadors en camins i diagnosi socioambiental del Camí de Cavalls de Menorca 2008: sector nord-est", redactat per Dídac Masana, Marta Morros i Esther Sanyé

Rational design of mitochondria targeted thiabendazole-based Ir(III) biscyclometalated complexes for a multimodal photodynamic therapy of cancer

Despite their outstanding properties as potential photosensitizers for photodynamic therapy (PDT), Ir(III) biscyclometalated complexes need both further developments to overcome remaining limitations and in-depth investigations into their mechanisms of action to reach clinic application in the treatment of cancer. This work describes the synthesis of a family of Ir(III) complexes of general formula [Ir(C^N)2(N^N′ )]Cl (N^N′ = thiabendazole-based ligands; C^N = ppy (2-phenylpyridinate) (Series A), or dfppy (2-(2,4-difluorophenyl)pyridinate) (Series B)) and their evaluation as potential PDT agents. These complexes are partially soluble in water and exhibit cytotoxic activity in the absence of light irradiation versus several cancer cell lines. Furthermore, the cytotoxic activity of derivatives of Series A is enhanced upon irradiation, particularly for complexes [1a]Cl and [3a]Cl, which show phototoxicity indexes (PI) above 20. Endocytosis was established as the uptake mechanism for [1a]Cl and [3a]Cl in prostate cancer cells by flow cytometry. These derivatives mainly accumulate in the mitochondria as shown by colocalization confocal microscopy experiments. Presumably, [1a]Cl and [3a]Cl induce death on cancer cells under irradiation through apoptosis triggered by a multimodal mechanism of action, which likely involves damage over mitochondrial DNA and mitochondrial membrane depolarization. Both processes seem to be the result of photocatalytic oxidation processes.We acknowledge the financial support provided by the Spanish Ministerio de Ciencia, Innovacion ´ y Universidades (RTI2018-100709-BC21, RTI2018-100709-B-C22) and CTQ (QMC)-RED2018-102471-T), Junta de Castilla y Leon ´ (BU087G19), Junta de Comunidades de CastillaLa Mancha-FEDER (JCCM) (grant SBPLY/19/180501/000260) and UCLM-FEDER (grants 2019-GRIN-27183 and 2019-GRIN-27209). I. Echevarría wants to acknowledge his fellowship to both the European Social Fund and Consejería de Educacion ´ de la Junta de Castilla y Leon ´ (EDU/1100/2017). E. Zafon wants to acknowledge her predoctoral fellowship to the Generalitat de Catalunya (AGAUR; 2021 FI_B 01036). We are also indebted to Jacinto Delgado, Pilar Castroviejo and Marta Mansilla (PCT of the Universidad de Burgos) for technical support and Jos´e Vicente Cuevas Vicario for advice and support with theoretical calculations and Gabriel García-Herbosa for providing us access to CV equipment