Metabolomic and Lipidomic Analysis of the Colorectal Adenocarcinoma Cell Line HT29 in Hypoxia and Reoxygenation.

The poor availability of oxygen and nutrients in malignant tumors drives the activation of various molecular responses and metabolic reprogramming in cancer cells. Hypoxic tumor regions often exhibit resistance to chemotherapy and radiotherapy. One approach to enhance cancer therapy is to indirectly increase tumor oxygen availability through targeted metabolic reprogramming. Thus, understanding the underlying metabolic changes occurring during hypoxia and reoxygenation is crucial for improving therapy efficacy. In this study, we utilized the HT29 colorectal adenocarcinoma cell line as a hypoxia-reoxygenation model to investigate central carbon and lipid metabolism. Through quantitative NMR spectroscopy and flow injection analysis - differential mobility spectroscopy-tandem mass spectrometry (FIA-DMS-MS/MS) analysis, we observed alterations in components of mitochondrial metabolism, redox status, specific lipid classes, and structural characteristics of lipids during hypoxia and up to 24 h of reoxygenation. These findings contribute to our understanding of the metabolic changes occurring during reoxygenation and provide the basis for functional studies aimed at metabolic pathways in cancer cells.

Recent advances in metabolomics analysis for early drug development.

The pharmaceutical industry adapted proteomics and other 'omics technologies for drug research early following their initial introduction. Although metabolomics lacked behind in this development, it has now become an accepted and widely applied approach in early drug development. Over the past few decades, metabolomics has evolved from a pure exploratory tool to a more mature and quantitative biochemical technology. Several metabolomics-based platforms are now applied during the early phases of drug discovery. Metabolomics analysis assists in the definition of the physiological response and target engagement (TE) markers as well as elucidation of the mode of action (MoA) of drug candidates under investigation. In this review, we highlight recent examples and novel developments of metabolomics analyses applied during early drug development.

Tumor microenvironment affects exogenous sodium/iodide symporter expression.

For decades, sodium/iodide symporter NIS-mediated iodide uptake has played a crucial role in the radioactive ablation of thyroid cancer cells. NIS-based gene therapy has also become a promising tool for the treatment of tumors of extrathyroidal origin. But its applicability has been hampered by reduced expression of NIS, resulting in a moderated capacity to accumulate 131I and in inefficient ablation. Despite numerous preclinical enhancement strategies, the understanding of NIS expression within tumors remains limited. This study aims at a better understanding of the functional behavior of exogenous NIS expression in the context of malignant solid tumors that are characterized by rapid growth with an insufficient vasculature, leading to hypoxia and quiescence. Using subcutaneous HT29NIS and K7M2NIS tumors, we show that NIS-mediated uptake and NIS expression at the plasma membrane of cancer cells are impaired in the intratumoral regions. For a better understanding of the underlying molecular mechanisms induced by hypoxia and quiescence (separately and in combination), we performed experiments on HT29NIS cancer cells. Hypoxia and quiescence were both found to impair NIS-mediated uptake through mechanisms including NIS mis-localization. Modifications in the expression of proteins and metabolites involved in plasma membrane localization and in energy metabolism were found using untargeted proteomics and metabolomics approaches. In conclusion, our results provide evidence that hypoxia and quiescence impair NIS expression at the plasma membrane, and iodide uptake. Our study also shows that the tumor microenvironment is an important parameter for successful NIS-based cancer treatment.

A colorimetric bioassay for quantitation of both basal and insulin-induced glucose consumption in 3T3-L1 adipose cells.

INTRODUCTION: The quantitation of glucose consumption in animal cell cultures is mainly based on the use of radiolabeled or fluorescent analogues, resulting in expensive and tedious procedures, requiring special equipment and, sometimes, with potential health and environmental risks. OBJECTIVES: The objective of this work was to evaluate the application of a blood plasma colorimetric assay to quantify glucose consumption in in vitro cultures of adipose cells. METHODS: We worked with 3T3-L1 adipose cells differentiated by 7-8 days, which were exposed to different initial glucose concentrations (5.5, 2.8 and 1.4 mM) for variable times, either in the absence or the presence of 100 nM insulin. Using a commercial colorimetric glucose assay, extracellular glucose was determined, and glucose uptake was calculated as the difference between the initial and final glucose concentration. RESULTS: The colorimetric assay allowed us to quantify glucose uptake in our cell model, observing a linear response over time (r 2 ≥0.9303) to the different glucose concentrations, both in the basal and insulin-induced condition. The insulin-stimulated glucose consumption was higher than basal consumption at all glucose concentrations evaluated, but significant differences were observed at 120-, 360- and 480-min in glucose 5.5 mM (p ≤ 0.01, n = 5), and 240 min in glucose 1.4 mM (p ≤ 0.01, n = 5). A V max of 4.1 and 5.9 nmol/ml/min (basal and insulin-induced, respectively) and a K m of 1.1 mM (same in basal vs insulin-stimulated) were calculated. The bioassay was also useful in a pharmacological context: in glucose 1.4 mM, glucose consumption showed an effect that depended on insulin concentration, with a calculated EC50 of 18.4 ± 1.1 nM. CONCLUSIONS: A simple and low-cost bioassay is proposed to quantify glucose consumption in 3T3-L1 adipose cells.

Lipid metabolism of leukocytes in the unstimulated and activated states.

Lipidomics has emerged as a powerful technique to study cellular lipid metabolism. As the lipidome contains numerous isomeric and isobaric species resulting in a significant overlap between different lipid classes, cutting-edge analytical technology is necessary for a comprehensive analysis of lipid metabolism. Just recently, differential mobility spectrometry (DMS) has evolved as such a technology, helping to overcome several analytical challenges. We here set out to apply DMS and the Lipidyzer™ platform to obtain a comprehensive overview of leukocyte-related lipid metabolism in the resting and activated states. First, we tested the linearity and repeatability of the platform by using HL60 cells. We obtained good linearities for most of the thirteen analyzed lipid classes (correlation coefficient > 0.95), and good repeatability (%CV < 15). By comparing the lipidome of neutrophils (PMNs), monocytes (CD14+), and lymphocytes (CD4+), we shed light on leukocyte-specific lipid patterns as well as lipidomic changes occurring through differential stimulation. For example, at the resting state, PMNs proved to contain higher amounts of triacylglycerides compared to CD4+ and CD14+ cells. On the other hand, CD4+ and CD14+ cells contained higher levels of phospholipids and ceramides. Upon stimulation, diacylglycerides, hexosylceramides, phosphatidylcholines, phosphoethanolamines, and lysophosphoethanolamines were upregulated in CD4+ cells and PMNs, whereas CD14+ cells did not show significant changes. By exploring the fatty acid content of the significantly upregulated lipid classes, we mainly found increased concentrations of very long and polyunsaturated fatty acids. Our results indicate the usefulness of the Lipidyzer™ platform for studying cellular lipid metabolism. Its application allowed us to explore the lipidome of leukocytes. Graphical abstract.

Recursos para la enseñanza-aprendizaje de temas complejos de Bioquímica en la educación médica / Resources for the teaching-learning of complex biochemistry topics in medical education

Introducción: las tecnologías de la información y la comunicación (TICs) han modificado la forma en que el conocimiento es transmitido y asimilado. En la educación médica son consideradas fundamentales para la optimización del proceso enseñanza-aprendizaje, por favorecer la apropiación e integración del conocimiento, y apoyar las actividades presenciales en el aula. Una efectiva aplicación de estas herramientas requiere la identificación de las temáticas de más difícil comprensión para los estudiantes, permitiendo un direccionamiento preciso de su uso para la solución de los problemas de aprendizaje. Métodos: se identificó el tópico de Bioquímica con mayor dificultad y se diseñó una herramienta virtual con diapositivas animadas, dibujos y gráficas que lo abordara. Los estudiantes recibieron orientaciones conceptuales que prepararon y discutieron con el profesor; posteriormente, accedieron a la herramienta para reforzar el estudio independiente. Se evaluó la eficacia de la herramienta al comparar los resultados de las evaluaciones antes y después de aplicarla y se evaluó la actitud de los estudiantes frente a su uso. Resultados: el índice de dificultad global identificó el metabolismo de compuestos nitrogenados como un tema crítico. La implementación de la herramienta aumentó el éxito en las evaluaciones intrasemestrales e intersemestrales. La actitud de los estudiantes frente al uso de la herramienta fue favorable, la consideraron útil para reforzar sus conocimientos y mejorar su formación académica. Conclusión: el uso orientado de las tecnologías de la información y la comunicación TICs en la educación superior favorece el proceso de autoaprendizaje y plantea la necesidad de una mayor integración e implementación estructurada y adaptada de este tipo de herramientas al entorno estudiantil(AU)

Introduction: Information and communication technologies (ICTs) have modified the way knowledge is transmitted and assimilated. In medical education, they are considered fundamental for the optimization of the teaching-learning process, to favor the appropriation and integration of knowledge, and to support classroom activities. An effective application of these tools requires the identification of the most difficult topics for students, allowing to precisely address their use for the solution of learning problems. Methods: The Biochemistry topic with more difficulties was identified and a virtual tool was designed with animated slides, drawings and graphs that would address it. Students received conceptual guidance that they prepared and discussed with the professor. Later on, they accessed the tool to reinforce homework. The efficacy of the tool was evaluated on comparing the results of the evaluations before and after applying it and evaluated the students' attitude towards their use. Results: The global difficulty index identified the metabolism of nitrogen compounds as a critical issue. The implementation of the tool increased the success in the intra- and inter-semester quizzes. The students' attitude towards the use of the tool was favorable, they considered it useful to reinforce their knowledge and to improve their academic training. Conclusion: The use of the information and communication technologies in higher education favors the process of self-learning and raises the need for a greater integration or structured and adapted implementation of this type of tools to the students' environment(AU)

[STAT3 activation by hypoxia in in vitro models of cervix cancer and endothelial cells].

INTRODUCTION: The biological behavior of cancer cells is influenced by the tumor microenvironment in which they develop. In this context, stressor stimuli such as hypoxia are considered critical for tumor development and therapeutic management. Cellular response to various stimuli is evidenced in the activation of intracellular signaling pathways such as JAK/STAT, which is one of the most important for its effects in differentiation and cell proliferation. OBJECTIVE: To evaluate the condition of the JAK/STAT pathway through the expression/activation of the STAT3 protein in cervix cancer cells (HeLa) and endothelial cells (EA.hy926) subjected to hypoxia. MATERIAL AND METHODS: Cell lines were subjected to physical (1% O2) or chemical (deferoxamine, DFO, 100 µM) hypoxia for 2, 6 and 24 hours. Changes in the expression and activation of STAT3, and its subcellular localization by indirect immunofluorescence, were determined by western blot. RESULTS: Hypoxia was evidenced by the activation and translocation to the nucleus of HIF-1. Neither physical nor chemical hypoxia altered STAT3 expression, but it did affect its activation, as seen in its phosphorylation and translocation to the nucleus in the two models under study. CONCLUSIONS: The present study highlights the importance of hypoxia as a stimulus that modifies the activation of the STAT3 protein in HeLa and EA.hy926 cells, which makes it an important factor in the design of therapeutic strategies against cancer.

Oxidative Stress Promotes Doxorubicin-Induced Pgp and BCRP Expression in Colon Cancer Cells Under Hypoxic Conditions.

P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) are ATP binding cassette (ABC) transporters that are overexpressed in different drug-resistant cancer cell lines. In this study, we investigated whether doxorubicin promotes Pgp and/or BCRP expression to induce drug resistance in colon cancer cells under hypoxic conditions. We analyzed HIF-1α activity via ELISA, Pgp, and BCRP expression by qRT-PCR and the relationship between doxorubicin uptake and ABC transporter expression via confocal microscopy in HT-29WT and HT-29 doxorubicin-resistant colon cancer cells (HT-29DxR). These cells were treated with doxorubicin and/or CoCl2 (chemical hypoxia), and reactive oxygen species inductors. We found that the combination of chemically induced hypoxia and doxorubicin promoted Pgp mRNA expression within 24 h in HT-29WT and HT-29DxR cells. Both doxorubicin and CoCl2 alone or in combination induced Pgp and BCRP expression, as demonstrated via confocal microscopy in each of the above two cell lines. Thus, we surmised that Pgp and BCRP expression may result from synergistic effects exerted by the combination of doxorubicin-induced ROS production and HIF-1α activity under hypoxic conditions. However, HIF-1α activity disruption via the administration of E3330, an APE-1 inhibitor, downregulated Pgp expression and increased doxorubicin delivery to HT-29 cells, where it served as a substrate for Pgp, indicating the existence of an indirect relationship between Pgp expression and doxorubicin accumulation. Thus, we concluded that Pgp and BCRP expression can be regulated via cross-talk between doxorubicin and hypoxia, promoting drug resistance in HT-29 WT, and HT-29DxR cells and that this process may be ROS dependent. J. Cell. Biochem. 118: 1868-1878, 2017. © 2017 Wiley Periodicals, Inc.

Activación de STAT3 por hipoxia en modelos in vitro de cáncer de cuello uterino y en células endoteliales / STAT3 activation by hypoxia in in vitro models of cervix cancer and endothelial cells

resumen Introducción: El microambiente tumoral influye en el comportamiento de las células cancerosas. Especialmente, el estímulo de agentes estresantes, como la hipoxia, se convierte en un factor crítico para la evolución y el tratamiento del cáncer. La reacción celular frente a diversos estímulos se manifiesta en la activación de vías de señalización como la JAK/STAT, una de las más importantes por sus efectos en la diferenciación y proliferación celular. Objetivo: Evaluar el estado de la vía JAK/STAT mediante la expresión o activación de la proteína STAT3 en células de cáncer de cuello uterino (HeLa) y en células endoteliales (EA.hy926) sometidas a hipoxia. Materiales y métodos: Las líneas celulares se sometieron a condiciones de hipoxia física (1 % de O2) o química (100 μM de deferoxamina, DFO) durante dos, seis y 24 horas. Mediante Western blot se determinó el cambio en la expresión y activación de STAT3, y mediante inmunofluorescencia indirecta su localización subcelular. Resultados:. La hipoxia se evidenció por la activación y translocación al núcleo del HIF-1. Ni la hipoxia física ni la química alteraron la expresión de STAT3, pero sí la activación, según se comprobó por su fosforilación y su translocación al núcleo en los dos modelos bajo estudio. Conclusiones: Se evidenció la importancia de la hipoxia como un estímulo que modifica la activación de la proteína STAT3 en las células HeLa y EA.hy926, lo cual la convierte en un elemento importante en el diseño de estrategias terapéuticas contra el cáncer.

Abstract Introduction: The biological behavior of cancer cells is influenced by the tumor microenvironment in which they develop. In this context, stressor stimuli such as hypoxia are considered critical for tumor development and therapeutic management. Cellular response to various stimuli is evidenced in the activation of intracellular signaling pathways such as JAK/STAT, which is one of the most important for its effects in differentiation and cell proliferation. Objective: To evaluate the condition of the JAK/STAT pathway through the expression/activation of the STAT3 protein in cervix cancer cells (HeLa) and endothelial cells (EA.hy926) subjected to ypoxia. Material and methods: Cell lines were subjected to physical (1% O2) or chemical (deferoxamine, DFO, 100 μM) hypoxia for 2, 6 and 24 hours. Changes in the expression and activation of STAT3, and its subcellular localization by indirect immunofluorescence, were determined by western blot. Results: Hypoxia was evidenced by the activation and translocation to the nucleus of HIF-1. Neither physical nor chemical hypoxia altered STAT3 expression, but it did affect its activation, as seen in its phosphorylation and translocation to the nucleus in the two models under study. Conclusions: The present study highlights the importance of hypoxia as a stimulus that modifies the activation of the STAT3 protein in HeLa and EA.hy926 cells, which makes it an important factor in the design of therapeutic strategies against cancer.

Contribución del programa de fortalecimiento académico a la permanencia universitaria de estudiantes de Medicina / Contributions strengthening academic program in biochemistry at the university stay in Medicine i: en

Introducción: la permanencia de los estudiantes en Medicina implicó el desarrollo de estrategias dirigidas a disminuir la deserción académica. El Programa de Fortalecimiento académico de la Universidad del Rosario, ha contribuido a este logro a partir del acompañamiento de los estudiantes en su aprendizaje. Objetivo: analizar el éxito y la calidad académicos de estudiantes de Medicina que reingresaron a la carrera luego de cursar y aprobar un Programa de Fortalecimiento Académico diseñado para reforzar las asignaturas que causaron la pérdida del cupo. Métodos: estudio tipo censo que incluyó a todos los estudiantes inscritos (n = 113) en las asignaturas de refuerzo en Bioquímica del Programa, desde el primer semestre del 2008 al segundo del 2012. Resultados: el mayor número de inscritos al Programa se presentó en las asignaturas de refuerzo en Bioquímica I y II: 42 por ciento (n = 58) y el 50 por ciento (n = 56). El 58 por ciento (n = 66) de los estudiantes que aprobaron el Programa obtuvieron el reingreso al pregrado y permanecieron activos en la carrera de Medicina. El 18 por ciento de los que permanecieron en la Universidad, superó el parámetro de buena calidad académica, con notas ≥ 4,0 una vez cursaron las asignaturas. Conclusiones: desde el ámbito de la Bioquímica, el Programa ha contribuido a la permanencia estudiantil en la carrera de Medicina, acorde con el reto de las políticas públicas. La pérdida del cupo por bajo rendimiento académico del 21,8 por ciento (n = 87) de estudiantes que reingresaron al pregrado, indica la orientación de acciones que incidan en factores como el aislamiento social, problemas familiares o de salud, y la orientación vocacional(AU)

Introduction: The retention of students in Medicine involves development of strategies aimed at reducing academic desertion. Academic Support Program of the Universidad del Rosario, has contributed to this achievement from accompanying students in their learning. Objective: The aim of this study was to analyze the success and quality in academic promotion of students from Health Sciences at the University of Rosario, who entered the Strengthening Program, and previously lost their enrollment in Medicine because Biochemistry subjects. Methods: Census study that includes all students enrolled in the program (113) with reinforcement in Biochemistry subjects from the first half of 2008 to second in 2012. Results: 58 percent (n = 66) of students remained and obtaining readmission to the University and active status likewise undergraduate students in the medical career. The highest number was registered in the subjects Biochemistry reinforcement I and II: 42 percent (n = 58) and 50 percent (n = 56) respectively. 18 percent of those who stayed in college, exceeded the parameter of good academic quality, with notes ≥ 4,0 in these subjects. Conclusions: Since Biochemistry context, the Strengthening Program has contributed to student retention in the medical career and also according to the challenge of public policy. The loss of quota for poor academic performance 21.8 percent (n = 87) of students who were readmitted to undergraduate indicates the orientation of activities influencing factors such as social isolation, family or health problems, and vocational guidance(AU)

Characterization of small-molecule inhibitors of the sodium iodide symporter.

The sodium/iodide symporter (NIS) mediates the active transport of iodide from the bloodstream into thyrocytes. NIS function is strategic for the diagnosis and treatment of various thyroid diseases. In addition, a promising anti-cancer strategy based on targeted NIS gene transfer in non-thyroidal cells is currently developed. However, only little information is available concerning the molecular mechanism of NIS-mediated iodide translocation. Ten small molecules have recently been identified using a high-throughput screening method for their inhibitory effect on iodide uptake of NIS-expressing mammalian cells. In the present study, we analyzed these compounds for their rapid and reversible effects on the iodide-induced current in NIS-expressing Xenopus oocytes. Four molecules almost completely inhibited the iodide-induced current; for three of them the effect was irreversible, for one compound the initial current could be fully re-established after washout. Three molecules showed a rapid inhibitory effect of about 75%, half of which was reversible. Another three compounds inhibited the iodide-induced current from 10 to 50%. Some molecules altered the membrane conductance by themselves, i.e. in the absence of iodide. For one of these molecules the observed effect was also found in water-injected oocytes whereas for some others the iodide-independent effect was associated with NIS expression. The tested molecules show a surprisingly high variability in their possible mode of action, and thus are promising tools for further functional characterization of NIS on a molecular level, and they could be useful for medical applications.

Immunoanalysis indicates that the sodium iodide symporter is not overexpressed in intracellular compartments in thyroid and breast cancers.

OBJECTIVE: The active transport of iodide into thyroid cells is mediated by the Na(+)/I(-) symporter (NIS) located in the basolateral membrane. Strong intracellular staining with anti-NIS antibodies has been reported in thyroid and breast cancers. Our initial objective was to screen tumour samples for intracellular NIS staining and then to study the mechanisms underlying the altered subcellular localization of the transporters. METHODS: Immunostaining using three different anti-NIS antibodies was performed on paraffin-embedded tissue sections from 93 thyroid or breast cancers. Western blot experiments were carried out to determine the amount of NIS protein in 20 samples. RESULTS: Using three different anti-NIS antibodies, we observed intracellular staining in a majority of thyroid tumour samples. Control immunohistochemistry and western blot experiments indicated that this intracellular staining was due to non-specific binding of the antibodies. In breast tumours, very weak intracellular staining was observed in some samples. Western blot experiments suggest that this labelling is also non-specific. CONCLUSIONS: Our results strongly indicate that the NIS protein level is low in thyroid and breast cancers and that the intracellular staining obtained with anti-NIS antibodies corresponds to a non-specific signal. Accordingly, to increase the efficiency of radiotherapy for thyroid cancers and to enable the use of radioiodine in the diagnosis and therapy of breast tumours, improving NIS targeting to the plasma membrane will not be sufficient. Instead, increasing the expression level of NIS should remain the major goal of this field.