Study of mechanisms of cytotoxicity and resistance of Trastuzumab in HER2+ tumor spheroids

En este trabajo de tesis estudiamos los mecanismos de acción y resistencia al anticuerpo monoclonal Trastuzumab (Tz) anti HER2+, empleando un modelo de cultivo 3D que mimetiza tumores sólidos y avasculares. Generamos esferoides a partir de las células de adenocarcinoma mamario humano BT474 (HER2+) y evidenciamos la existencia de subpoblaciones celulares heterogéneas, con un gradiente de células proliferantes, quiescentes, hipóxicas, apoptóticas y autofágicas hacia su interior. Esta organización 3D moduló la respuesta al Tz, demostrando menor sensibilidad a su efecto antitumoral que las mismas células cultivadas como monocapas tradicionales. Para investigar la participación del sistema inmune, co-cultivamos esferoides con macrófagos y encontramos un mayor efecto antitumoral de Tz. Al analizar los mecanismos de acción de Tz, no detectamos inducción de apoptosis pero sí un arresto de las células en G0/G1. Tz disminuyó la población apoptótica descripta sólo en esferoides y fue capaz de inducir autofagia. Al inhibir la autofagia, logramos aumentar la sensibilidad al Tz y describimos una interacción clave entre apoptosis y autofagia. Confirmamos este resultado estableciendo una línea celular resistente al Tz que demostró ser más sensible a la inhibición de la autofagia que la línea parental BT474. En síntesis, este trabajo demuestra que en una organización en 3D existe una interacción entre los mecanismos de muerte y sobrevida celular en respuesta a Tz y que de su balance depende el desarrollo de resistencia. Esto podría ser la clave para reconocer nuevos blancos terapéuticos y superar la resistencia a Tz.In this thesis, we study the mechanisms of action and resistance development in the treatment with the anti HER2 monoclonal antibody Trastuzumab (Tz), using a model of cell growth in 3D that mimics the structure of solid and avascular tumors. We cultured human mammary adenocarcinoma BT474 cells (HER2+) as spheroids and observed a gradient of proliferating, quiescent, hypoxic, apoptotic and autophagic cells towards the inner core. This 3D organization modulated response to Tz, being spheroids less sensitive to its antitumoral effect than traditional monolayers. In order to study the participation of the immune system, we co-cultured spheroids with macrophages and found that their presence increased the antitumoral effect of Tz. When we studied the mechanisms of action of Tz, we did not observe apoptosis induction but found cell arrest in G0/G1 phase. Tz reduced the apoptotic population only detected in spheroids and induced autophagy. We were able to increase sensitivity to Tz by autophagy inhibition and described a link between apoptosis and autophagy. We confirmed this result by developing a Tz resistant cell line that was more sensitive to autophagic inhibition than the parental BT474 cells. In summary, our experiments shows that in 3D cell organization, there is a link between death and survival mechanisms in the response to Tz and that resistance depends on their balance. This could be the key to find new therapeutic targets and overcome Tz resistance.Fil: Rodríguez, Cristina Elisa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

El tutor como agente de cambio en la formación integral del estudiante

La tutoría es una función inherente al quehacer del docente, que se refleja en el entorno social del alumno y por lo mismo, es considerada como un elemento de cambio en la Responsabilidad Social Universitaria (RSU), la cual consiste en el acompañamiento, supervisión, orientación y guía del tutor en relación con el beneficiado al que se busca fortalecer en su desarrollo psicológico, social, académico y profesional. La labor del tutor cumple con el compromiso social del Modelo Educativo de la UANL, misma que se ve reflejada en su rendimiento académico, diversas formas de integración, participación universitaria entre otras. En la relación del tutor – tutorado debe mantenerse un ambiente de respeto y armonía entre ambos participantes y también deben aplicarse principios éticos y morales para que esta función tutorial rinda los frutos esperados

Alucinosis peduncular: descripción de un caso y revisión del tema

Elisa Demicheli: Instituto de Neurología, Facultad de Medicina, Universidad de la República, Uruguay. Contacto: [email protected] Fernanda Rodríguez Erazú: Instituto de Neurología, Facultad de Medicina, Universidad de la República, Uruguay.-- Cristina Vázquez: Instituto de Neurología, Facultad de Medicina, Universidad de la República, Uruguay.La alucinosis peduncular es el término utilizado para describir una forma rara de alucinaciones visuales complejas, vívidas, coloridas y generalmente recurrentes que ocurren en relación a lesiones del tronco encefálico y el tálamo. Es una patología infrecuente y su fisiopatología es controvertida. Describimos el caso de una mujer de 38 años con alucinosis peduncular asociada a compresión extrínseca del tronco encefálico secundaria a un schwannoma vestibular. Analizamos las características clínicas y los mecanismos fisiopatológicos subyacentes.Peduncular hallucinosis is a clinical condition characterized by vivid, colorful, complex visual hallucinations that often recur in time and are described in association with midbrain and thalamic lesions. It is a rare phenomenon and its precise pathophysiology is unknown. We describe the case of a 38-year-old woman who developed peduncular hallucinosis in relation to extrinsic compression of the midbrain secondary to a vestibular schwannoma. Clinical features and underlying pathophysiological mechanisms are discussed.A alucinose peduncular é o termo usado para descrever uma forma rara de alucinações visuais com plexas, vívidas, coloridas e geralmente recorrentes que ocorrem em relação às lesões do tronco encefálico e do tálamo. É uma patologia infreqüente e sua fisiopatologia é controversa. Descrevemos o caso de uma mulher de 38 anos de idade com alucinose peduncular associada à com pressão extrínseca do tronco encefálico secundária ao schwannoma vestibular. Analisamos as características clínicas e os mecanismos fisiopatológicos subjacentes

Hydrophobic air pollutants removal at one second gas contact in a multi-channel capillary bioreactor

Producción CientíficaBiological processes are increasingly applied for gas purification as a sustainable and economical alternative to conventional physical-chemical processes (chemical absorption, incineration, adsorption). Although biological gas treatment is accepted as an economical, safe, and reliable air pollution control technology, it faces important limitations when applied for the treatment of poorly water-soluble compounds due to mass transfer limitations. A twenty-five capillary channels bioreactor was studied to characterize mass transfer coefficients and the removal of hydrophobic air pollutants under segmented gas-liquid flow pattern. The removal efficiency of hexane, toluene and α-pinene vapors reached values up to about 75%, 99% and 75%, respectively, at a gas contact time of less than 1 second, which is at least one, but closer to two orders of magnitude shorter than conventional biological gas purification systems. The bioreactor displayed stable operation for 100 days and was robust against common upsets, which opens the new opportunities for expanding the application field of biological processes for air pollution control and the mitigation of greenhouse gases in dilute air streams.Ministerio de Ciencia e Innovación y Ministerio de Universidades [project RTI2018-0-096441-B-I00]Junta de Castilla y León - EU-FEDER [grant number CLU 2017-09 y CL-EI-2021-07

Sialic acid removal by trans-sialidase modulates MMP-2 activity during Trypanosoma cruzi infection

Matrix metalloproteinases (MMPs) not only play a relevant role in homeostatic processes but are also involved in several pathological mechanisms associated with infectious diseases. As their clinical relevance in Chagas disease has recently been highlighted, we studied the modulation of circulating MMPs by Trypanosoma cruzi infection. We found that virulent parasites from Discrete Typing Units (DTU) VI induced higher proMMP-2 and MMP-2 activity in blood, whereas both low (DTU I) and high virulence parasites induced a significant decrease in proMMP-9 plasma activity. Moreover, trans-sialidase, a relevant T. cruzi virulence factor, is involved in MMP-2 activity modulation both in vivo and in vitro. It removes α2,3-linked sialyl residues from cell surface glycoconjugates, which then triggers the PKC/MEK/ERK signaling pathway. Additionally, bacterial sialidases specific for this sialyl residue linkage displayed similar MMP modulation profiles and triggered the same signaling pathways. This novel pathogenic mechanism, dependent on sialic acid removal by the neuraminidase activity of trans-sialidase, can be exploited by different pathogens expressing sialidases with similar specificity. Thus, here we present a new pathogen strategy through the regulation of the MMP network.Fil: Musikant, Alejandro Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Higa, Romina Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Rodríguez, Cristina Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Edreira, Martin Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Campetella, Oscar Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Jawerbaum, Alicia Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Leguizamon, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Ectoines production from biogas in pilot bubble column bioreactors and their subsequent extraction via bio-milking

Producción CientíficaDespite the potential of biogas from waste/wastewater treatment as a renewable energy source, the presence of pollutants and the rapid decrease in the levelized cost of solar and wind power constrain the use of biogas for energy generation. Biogas conversion into ectoine, one of the most valuable bioproducts (1000 €/kg), constitutes a new strategy to promote a competitive biogas market. The potential for a stand-alone 20 L bubble column bioreactor operating at 6% NaCl and two 10 L interconnected bioreactors (at 0 and 6% NaCl, respectively) for ectoine production from biogas was comparatively assessed. The stand-alone reactor supported the best process performance due to its highest robustness and efficiency for ectoine accumulation (20–52 mgectoine/gVSS) and CH4 degradation (up to 84%). The increase in N availability and internal gas recirculation did not enhance ectoine synthesis. However, a 2-fold increase in the internal gas recirculation resulted in an approximately 1.3-fold increase in CH4 removal efficiency. Finally, the recovery of ectoine through bacterial bio-milking resulted in efficiencies of >70% without any negative impact of methanotrophic cell recycling to the bioreactors on CH4 biodegradation or ectoine synthesis.European Union's Horizon 2020 research and innovation program under grant agreement No 837998European Union's Horizon 2020 research and innovation program and the Bio-based Industries ConsortiumJunta de Castilla y León y EU-FEDER (CLU 2017–09, CL-EI-2021–07, UIC 315

Characterization and In Vivo Anti-Inflammatory Efficacy of Copal (Dacryodes peruviana (Loes.) H.J. Lam) Essential Oil

Essential oils are natural aromatic substances that contain complex mixtures of many volatile compounds frequently used in pharmaceutical and cosmetic industries. Dacryodes peruviana (Loes.) H.J. Lam is a native species from Ecuador whose anti-inflammatory activity has not been previously reported, thus the aim of this study was to evaluate the anti-inflammatory activity of D. peruviana essential oil. To that end, essential oil from D. peruviana fruits was isolated by hydrodistillation and characterized physically and chemically. The tolerance of the essential oil was analyzed by cytotoxicity studies using human keratinocytes. The anti-inflammatory activity was evaluated by an arachidonic acid-induced edema model in mouse ear. The predominant compounds in D. peruviana essential oil were α-phellandrene, limonene, and α-pinene, with the three compounds reaching approximately 83% of the total composition. Tolerance studies showed high biocompatibility of this essential oil with human keratinocytes. In vivo studies demonstrated a moisturizing effect and an alleviation of several events occurred during the inflammatory process after topical treatment with D. peruviana essential oil such as decline in skin edema; reduction in leukocytic infiltrate; and decrease in inflammatory cytokines TNFα, IL-8, IL-17A, and IL-23. Therefore, this essential oil could be an attractive treatment for skin inflammation

Pulmonary surfactant and drug delivery: Vehiculization of a tryptophan-tagged antimicrobial peptide over the air-liquid interfacial highway

This work evaluates interaction of pulmonary surfactant (PS) and antimicrobial peptides (AMPs) in order to investigate (i) if PS can be used to transport AMPs, and (ii) to what extent PS interferes with AMP function and vice versa. This, in turn, is motivated by a need to find new strategies to treat bacterial infections in the airways. Low respiratory tract infections (LRTIs) are a leading cause of illness and death worldwide that, together with the problem of multidrug-resistant (MDR) bacteria, bring to light the necessity of developing effective therapies that ensure high bioavailability of the drug at the site of infection and display a potent antimicrobial effect. Here, we propose the combination of AMPs with PS to improve their delivery, exemplified for the hydrophobically endtagged AMP, GRR10W4 (GRRPRPRPRPWWWW-NH2), with previously demonstrated potent antimicrobial activity against a broad spectrum of bacteria under various conditions. Experiments using model systems emulating the respiratory interface and an operating alveolus, based on surface balances and bubble surfactometry, served to demonstrate that a fluorescently labelled version of GRR10W4 (GRR10W4-F), was able to interact and insert into PS membranes without affecting its biophysical function. Therefore, vehiculization of the peptide along air–liquid interfaces was enabled, even for interfaces previously occupied by surfactants layers. Furthermore, breathing-like compression-expansion dynamics promoted the interfacial release of GRR10W4-F after its delivery, which could further allow the peptide to perform its antimicrobial function. PS/GRR10W4-F formulations displayed greater antimicrobial effects and reduced toxicity on cultured airway epithelial cells compared to that of the peptide alone. Taken together, these results open the door to the development of novel delivery strategies for AMPs in order to increase the bioavailability of these molecules at the infection site via inhaled therapies

Semi-Solid Dosage Forms Containing Pranoprofen-Loaded NLC as Topical Therapy for Local Inflammation: In Vitro, Ex Vivo and In Vivo Evaluation

Pranoprofen (PRA)-loaded nanostructured lipid carriers (NLC) have been dispersed into blank gels composed of 1% of Carbomer 940 (PRA-NLC-Car) and 3% of Sepigel® 305 (PRA-NLC-Sep) as a novel strategy to refine the biopharmaceutical profile of PRA, for dermal administration in the treatment of skin inflammation that may be caused by possible skin abrasion. This stratagem intends to improve the joining of PRA with the skin, improving its retention and anti-inflammatory effect. Gels were evaluated for various parameters such as pH, morphology, rheology, and swelling. In vitro drug release research and ex vivo permeation through the skin were carried out on Franz diffusion cells. Additionally, in vivo assays were carried out to evaluate the anti-inflammatory effect, and tolerance studies were performed in humans by evaluating the biomechanical properties. Results showed a rheological profile common of semi-solid pharmaceutical forms for dermal application, with sustained release up to 24 h. In vivo studies using PRA-NLC-Car and PRA-NLC-Sep in Mus musculus mice and hairless rats histologically demonstrated their efficacy in an inflammatory animal model study. No signs of skin irritation or modifications of the skin's biophysical properties were identified and the gels were well tolerated. The results obtained from this investigation concluded that the developed semi-solid formulations represent a fitting drug delivery carrier for PRA's transdermal delivery, enhancing its dermal retention and suggesting that they can be utilized as an interesting and effective topical treatment for local skin inflammation caused by a possible abrasion