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Insulin and insulin-like growth factor-1 stimulate specific responses in arteries, which may be disrupted by diet-induced obesity. We examined (1) temporal effects of high-fat diet compared to low-fat diet in mice on insulin receptor, insulin-like growth factor-1 receptor, insulin receptor/insulin-like growth factor-1 receptor hybrid receptor expression and insulin/insulin-like growth factor-1-mediated Akt phosphorylation in aorta; and (2) effects of high-fat diet on insulin and insulin-like growth factor-1-mediated Akt phosphorylation and vascular tone in resistance arteries. Medium-term high-fat diet (5 weeks) decreased insulin-like growth factor-1 receptor expression and increased hybrid expression (~30%) only. After long-term (16 weeks) high-fat diet, insulin receptor expression was reduced by ~30%, insulin-like growth factor-1 receptor expression decreased a further ~40% and hybrid expression increased a further ~60%. Independent correlates of hybrid receptor expression were high-fat diet, duration of high-fat diet and plasma insulin-like growth factor-1 (all p

The insulin-like growth factor (IGF) system comprises multiple growth factor receptors, including insulin-like growth factor 1 receptor (IGF-1R), insulin receptor (IR)-A and-B. These receptors are activated upon binding to their respective growth factor ligands, IGF-I, IGF-II and insulin, and play an important role in development, maintenance, progression, survival and chemotherapeutic response of ovarian cancer. In many pre-clinical studies anti-IGF-1R/IR targeted strategies proved effective in reducing growth of ovarian cancer models. In addition, anti-IGF-1R targeted strategies potentiated the efficacy of platinum based chemotherapy. Despite the vast amount of encouraging and promising pre-clinical data, anti-IGF-1R/IR targeted strategies lacked efficacy in the clinic. The question is whether targeting the IGF-1R/IR signaling pathway still holds therapeutic potential. In this review we address the complexity of the IGF-1R/IR signaling pathway, including receptor heterodimerization within and outside the IGF system and downstream signaling. Further, we discuss the implications of this complexity on current targeted strategies and indicate therapeutic opportunities for successful targeting of the IGF-1R/IR signaling pathway in ovarian cancer. Multiple-targeted approaches circumventing bidirectional receptor tyrosine kinase (RTK) compensation and prevention of system rewiring are expected to have more therapeutic potential.

The insulin-like growth factor (IGF) system comprises multiple growth factor receptors, including insulin-like growth factor 1 receptor (IGF-1R), insulin receptor (IR) -A and -B. These receptors are activated upon binding to their respective growth factor ligands, IGF-I, IGF-II and insulin, and play an important role in development, maintenance, progression, survival and chemotherapeutic response of ovarian cancer. In many pre-clinical studies anti-IGF-1R/IR targeted strategies proved effective in reducing growth of ovarian cancer models. In addition, anti-IGF-1R targeted strategies potentiated the efficacy of platinum based chemotherapy. Despite the vast amount of encouraging and promising pre-clinical data, anti-IGF-1R/IR targeted strategies lacked efficacy in the clinic. The question is whether targeting the IGF-1R/IR signaling pathway still holds therapeutic potential. In this review we address the complexity of the IGF-1R/IR signaling pathway, including receptor heterodimerization within and outside the IGF system and downstream signaling. Further, we discuss the implications of this complexity on current targeted strategies and indicate therapeutic opportunities for successful targeting of the IGF-1R/IR signaling pathway in ovarian cancer. Multiple-targeted approaches circumventing bidirectional receptor tyrosine kinase (RTK) compensation and prevention of system rewiring are expected to have more therapeutic potential.

The insulin receptor (IR) mediates both metabolic and mitogenic effects especially when overexpressed or in clinical conditions with compensatory hyperinsulinemia, due to the metabolic pathway resistance, as obesity diabetes. In many cancers, IR is overexpressed preferentially as IR-A isoform, derived by alternative splicing of exon 11. The IR-A overexpression, and the increased IR-A:IR-B ratio, are mechanisms that promote the mitogenic response of cancer cells to insulin and IGF-2, which is produced locally by both epithelial and stromal cancer cells. In cancer IR-A, isoform predominance may occur for dysregulation at both mRNA transcription and post-transcription levels, including splicing factors, non-coding RNAs and protein degradation. The mechanisms that regulate IR isoform expression are complex and not fully understood. The IR isoform overexpression may play a role in cancer cell stemness, in tumor progression and in resistance to target therapies. From a clinical point of view, the IR-A overexpression in cancer may be a determinant factor for the resistance to IGF-1R target therapies for this issue. IR isoform expression in cancers may have the meaning of a predictive biomarker and co-targeting IGF-1R and IR-A may represent a new more efficacious treatment strategy.

We compared insulin and IGF effects in adipocytes expressing IR (insulin receptors), and preadipocytes expressing IR and IGF-IR (IGF-I receptors). Treatment of adipocytes with insulin, IGF-II or IGF-I resulted in phosphorylation of IR. Order of potency was insulinIGF-IIIGF-I. In preadipocytes IR, IGF-IR and insulin/IGF-I hybrid receptors (HR) were detected. Treatment of preadipocytes with IGF-I and IGF-II 10(-8)M resulted in activation of IGF-IR and IR whereas insulin was more potent in activating IR, with no effect on IGF-IR. In adipocytes glucose transport was 100-fold more sensitive to insulin than to IGFs and the maximal effect was higher with insulin. In preadipocytes glucose accumulation and DNA synthesis was equally sensitive to insulin and IGFs but the maximal effect was higher with IGF-I. In conclusion, insulin and IGF-I activate their cognate receptors and IGF-I also HR. IGF-II activates IR, IGF-IR and HR. Insulin and IGF-I are partial agonists to each other's receptors.

Las células son dispositivos de procesamiento de información, que integran millones de señales extracelulares e intracelulares para producir una respuesta celular óptima dentro de un organismo. Muchas enfermedades, por ejemplo el cáncer, pueden ser entendidas como alteraciones patológicas en las redes de señalización. Por lo que el estudio de los mecanismos de procesamiento de señales constituye uno de los problemas más complejos y al mismo tiempo más significativos en las investigaciones biológicas. Los eventos de señalización incluyen intrincadas redes de señalización, que encierran “loops” de retroalimentación, señalización cruzada con otras redes y la integración del estado interno de la célula, todos estos, regulados espacial y temporalmente. El sistema de señalización de los IGFs es una compleja red regulatoria que tiene funciones en todo el organismo, a nivel celular y subcelular. El sistema IGF está relacionado con el desarrollo del organismo y mantenimiento de la función celular normal. Además, ha sido relacionado en diversas condiciones patológicas con un papel particularmente importante en cáncer. Las similaridades estructurales entre el receptor de IGF y el receptor de insulina, permiten la formación de receptores híbridos, en donde una cadena IGF-1R αβ está conectada a una cadena InsR-A o InsR-B. Cuando se coexpresan los receptores de IGF y de insulina en la misma célula, estos receptores híbridos pueden formarse aleatoriamente y representan el tipo de receptor más abundante. Sin embargo, se conoce muy poco sobre su importancia en la transducción de señales y de los efectos biológicos que pueden estar modulando; este trabajo aborda el problema del estudio de la señalización del sistema IGF desde una perspectiva integradora que refleja el entorno biológico en el que se encuentra; haciendo uso tanto de técnicas clásicas de análisis, como técnicas de vanguardia se buscó entender los mecanismos que subyacen en el procesamiento de señales que desencadena en un efecto biológico. Las células de trofoblasto hacen parte de la placenta y son las encargadas de invadir el endometrio materno durante el proceso de implantación del blastocisto, además, evaden los efectores de la respuesta inmune materna, siendo de vital importancia para el desarrollo fetoplacental. La invasión del trofoblasto a la matriz extracelular del útero es un ejemplo de invasión altamente controlada. Este proceso comparte muchas características con tumores metastásicos, sin embargo se encuentra regulado espacial y temporalmente. A partir de la línea de trofoblasto HTR8, se obtuvieron dos líneas celulares establemente silenciadas en los receptores IGF-1R e IGF-2R/M6P con las que se realizaron ensayos de proliferación, migración, invasión, expresión de Mmp-9 y cAMP, paralelamente se efectuó un estudio proteómico de las proteínas activadas por IGF-2 en los modelos normal y silenciados con miras a obtener una visión integral delos fenómenos biológicos inducidos en la célula luego de la estimulación con IGFs. Los resultaron mostraron que los ligandos IGF son mediadores importantes de los fenómenos malignos compartidos entre las células de trofoblasto y las células cancerosas, tales como proliferación, migración e invasión. Estos efectos son mediados por los receptores híbridos InsR/IGF-1R y en ellos participan decenas de proteínas que fueron identificadas por medio de espectrometría de masas. Se estudiaron proteínas activadas por IGF-2 y se construyeron, a partir de ellas, redes de interacción proteína-proteína relacionadas con los principales efectos mediados por este ligando en células trofoblásticas. Empleando electroforesis en dos dimensiones y el modelo celular silenciado para el receptor IGF-1R, se evaluó su papel al analizar los cambios inducidos por su depleción en los mapas activación de proteínas. Finalmente, se empleo la línea celular silenciada establemente en el receptor IGF-2/M6P para estudiar su papel en los efectos bilógicos mediados por los IGFs y en las redes de señalización. Se encontró que la presencia del receptor tipo 2 es clave en la migración, invasión y expresión de Mmp-9. Adicionalmente se obtuvo evidencia de que este receptor puede activar receptores acoplados a proteína G, probablemente con intermediación de la S1P. Este trabajo es el primer estudio que aborda el problema de la señalización del sistema IGF desde una visión que enmarca las proteínas dentro de complejas redes de señalización. Empleando técnicas de análisis de fosfoproteómica en conjunto con ensayos de actividad biológica, se presenta evidencia sólida de la estrecha relación entre los tres receptores del sistema IGF en la regulación de los efectos biológicos mediados por los ligandos IGF-1 e IGF-2. Además, muestra el papel central del receptor IGF-2/M6P en la transducción de señales del sistema IGF y como su ausencia genera cambios notorios en el fosfoproteoma que se ven reflejados en los fenómenos biológicos más importantes en cáncer, migración e invasión. Estos resultados amplían el conocimiento de la señalización mediada por los IGFs, destacan la importancia del receptor IGF-2/M6P como un mediador clave en los fenómenos de transducción de señales; representan el primer estudio a gran escala de las redes de señalización activadas por los IGFs y su relación con fenómenos biológicos importantes para el desarrollo del cáncer. Cells are information processing devices, which integrate millions of extracellular and intracellular signals to produce an optimal cellular response within of an organism. Many diseases, for example cancer, can be understood as pathological alterations in the signalling networks. Therefore, the study of the signal processing mechanisms constitutes one of the most complex and at the same time more significant in biological research questions. The signaling events include intricate signaling networks, which enclose "feedback loops, cross-signaling with other networks and the integration of the internal state of the cell, all of these, regulated spatially and temporally. The signalling system of the IGFs is a complex regulatory network that has functions throughout the body, at the cellular and sub-cellular levels. The IGF system isrelated to the development of the organism and maintenance of cell function normal. In addition, it has been linked in various pathological conditions to a role particularly important in cancer. The structural similarities between the receptor of IGF and the insulin receptor, allow the formation of hybrid receptors, where an IGF-1R αβ string is connected to an InsR-A or InsR-B string. When co-express IGF and insulin receptors in the same cell, these receptors hybrids can be formed randomly and represent the most abundant receptor form. However, very little is known about its importance in transduction of signals and the biological effects they may be modulating; this paper addresses the problem of studying the signalling of the IGF system from a that reflects the biological environment in which it is found; making use of both of classic analysis techniques, as well as avant-garde techniques, we sought to understand the mechanisms underlying the signal processing that triggers an effect biological. The trophoblast cells are part of the placenta and are responsible for invading the maternal endometrium during the blastocyst implantation process, furthermore, they evade the effectors of the maternal immune response, being of vital importance for the fetoplacental development. The invasion of the trophoblast into the extracellular matrix of the uterus is an example of a highly controlled invasion. This process shares many characteristics with metastatic tumors, however it is spatially regulated and temporarily. From the HTR8 trophoblast line, two lines were obtained Stably silenced cell phones in the IGF-1R and IGF-2R/M6P receptors with which proliferation, migration, invasion, MMP-9 expression and cAMP, a parallel proteomic study of the proteins activated by IGF-2 in normal and silenced models in order to obtain a comprehensive view of biological phenomena induced in the cell after IGF stimulation. The results showed that IGF ligands are important mediators of the malignant phenomena shared between trophoblast cells and cells cancers, such as proliferation, migration and invasion. These effects are mediated by the InsR/IGF-1R hybrid receptors and involve dozens of proteins that were identified by mass spectrometry. Proteins were studied activated by IGF-2 and built from them networks of interaction protein-protein related to the main effects mediated by this ligand in trophoblastic cells. Using two-dimensional electrophoresis and the cell model silenced for the IGF-1R receptor, its role was evaluated by analyzing the induced changes for their depletion in the protein activation maps. Finally, the silenced cell line was used stably in the IGF-2/M6P to study its role in IGF-mediated bilogical effects and in the signalling networks. The presence of the type 2 receptor was found to be key in the migration, invasion and expression of Mmp-9. Additionally, evidence was obtained that this receptor can activate G-protein-coupled receptors, probably with intermediation of the S1P. This work is the first study to address the problem of system signalling IGF from a vision that frames proteins within complex networks of signaling. Using phosphoprotein analysis techniques in conjunction with biological activity tests, there is strong evidence of the close relationship between the three receptors of the IGF system in the regulation of biological effects mediated by ligands IGF-1 and IGF-2. It also shows the central role of the IGF-2/M6P receptor in the signal transduction of the IGF system and how its absence generates noticeable changes in the phosphoprotein which are reflected in the most important biological agents in cancer, migration and invasion. These results extend the knowledge of the signaling mediated by the IGFs, highlight the importance of IGF-2/M6P receptor as a key mediator in the transduction phenomena of signals; they represent the first large-scale study of signalling networks activated by the IGFs and their relationship with biological phenomena important to the development of cancer. Doctorado

The type 1 insulin-like growth factor receptor (IGF-1R) tyrosine kinase is an important mediator of the protumorigenic effects of IGF-I/II, and inhibitors of IGF-1R signaling are currently being tested in clinical cancer trials aiming to assess the utility of this receptor as a therapeutic target. Despite mounting evidence that the highly homologous insulin receptor (IR) can also convey protumorigenic signals, its direct role in cancer progression has not been genetically defined in vivo, and it remains unclear whether such a role for IR signaling could compromise the efficacy of selective IGF-1R targeting strategies. A transgenic mouse model of pancreatic neuroendocrine carcinogenesis engages the IGF signaling pathway, as revealed by its dependence on IGF-II and by accelerated malignant progression upon IGF-1R overexpression. Surprisingly, preclinical trials with an inhibitory monoclonal antibody to IGF-1R did not significantly impact tumor growth, prompting us to investigate the involvement of IR. The levels of IR were found to be significantly up-regulated during multistep progression from hyperplastic lesions to islet tumors. Its functional involvement was revealed by genetic disruption of the IR gene in the oncogene-expressing pancreatic β cells, which resulted in reduced tumor burden accompanied by increased apoptosis. Notably, the IR knockout tumors now exhibited sensitivity to anti–IGF-1R therapy; similarly, high IR to IGF-1R ratios demonstrably conveyed resistance to IGF-1R inhibition in human breast cancer cells. The results predict that elevated IR signaling before and after treatment will respectively manifest intrinsic and adaptive resistance to anti–IGF-1R therapies.