Type 2 diabetes mellitus (T2DM) ensues from diminished insulin sensitivity and abated compensatory insulin secretion. While diminished insulin secretion has a strong genetic origin, environmental factors are central in the development of insulin resistance; these include hyperinsulinemia and lipotoxicity. Insulin resistance results in the dysregulation of hypothalamic neurons that mediate its central actions: a key intermediary neuron is the neuropeptide Y/agouti-related peptide (NPY/AgRP) neuron. The hypothesis therefore was generated that insulin directly regulates NPY/AgRP neurons, and that prolonged insulin or palmitate, a prevalent free fatty acid (FFA), exposure inhibits neuronal insulin signaling. Using well characterized hypothalamic cell lines, mHypoE-46 or mHypoE-44, which express NPY, AgRP and insulin receptor signaling machinery, this hypothesis was examined in three studies. Correspondingly, insulin decreased NPY and AgRP mRNA expression in the mHypoE-46 cells, through an extracellular signal-regulated kinase (ERK) dependent mechanism; whereas prolonged exposure of NPY/AgRP cells to insulin or palmitate attenuated insulin signaling, determined by analysis of phosphorylated Akt. Insulin induced insulin receptor substrate-1 (IRS-1) serine 1101 phosphorylation in mHypoE-46 cells, utilizing the mTOR-S6K1 pathway, as the mTOR inhibitor rapamycin prevented IRS-1 serine phosphorylation. Insulin also decreased insulin receptor and IRS-1 protein levels; this was prevented by lysosomal and proteasomal pathway inhibitors, 3-methyladenine and epoxomicin, respectively. Importantly, rapamycin, epoxomicin or 3-methyladenine pre-treatment decreased the attenuation of insulin signaling during long-term insulin exposure. On the other hand, palmitate activated c-Jun N-terminal kinase (JNK), the apoptosis effector caspase 3, and induced endoplasmic reticulum (ER) stress in mHypoE-44 cells: JNK inhibition prevented ER stress. In an attempt to avert the deleterious effects of palmitate, the neuronal cells were treated with the 5`AMP-activated protein kinase (AMPK) activator AICAR, a possible insulin sensitizer. Interestingly, AICAR attenuated JNK and caspase 3 activation, and restored insulin signaling. These findings demonstrate that insulin directly regulates NPY/AgRP neuronal cells, and that insulin and palmitate provoke neuronal insulin resistance through different mechanisms. These findings substantiate the idea that environmental factors known to trigger peripheral insulin resistance may have consequences at the level of the individual hypothalamic neuron, which may ultimately contribute to the resulting pathophysiological states of obesity and T2DM.

Type 2 diabetes mellitus (T2DM) ensues from diminished insulin sensitivity and abated compensatory insulin secretion. While diminished insulin secretion has a strong genetic origin, environmental factors are central in the development of insulin resistance; these include hyperinsulinemia and lipotoxicity. Insulin resistance results in the dysregulation of hypothalamic neurons that mediate its central actions: a key intermediary neuron is the neuropeptide Y/agouti-related peptide (NPY/AgRP) neuron. The hypothesis therefore was generated that insulin directly regulates NPY/AgRP neurons, and that prolonged insulin or palmitate, a prevalent free fatty acid (FFA), exposure inhibits neuronal insulin signaling. Using well characterized hypothalamic cell lines, mHypoE-46 or mHypoE-44, which express NPY, AgRP and insulin receptor signaling machinery, this hypothesis was examined in three studies. Correspondingly, insulin decreased NPY and AgRP mRNA expression in the mHypoE-46 cells, through an extracellular signal-regulated kinase (ERK) dependent mechanism; whereas prolonged exposure of NPY/AgRP cells to insulin or palmitate attenuated insulin signaling, determined by analysis of phosphorylated Akt. Insulin induced insulin receptor substrate-1 (IRS-1) serine 1101 phosphorylation in mHypoE-46 cells, utilizing the mTOR-S6K1 pathway, as the mTOR inhibitor rapamycin prevented IRS-1 serine phosphorylation. Insulin also decreased insulin receptor and IRS-1 protein levels; this was prevented by lysosomal and proteasomal pathway inhibitors, 3-methyladenine and epoxomicin, respectively. Importantly, rapamycin, epoxomicin or 3-methyladenine pre-treatment decreased the attenuation of insulin signaling during long-term insulin exposure. On the other hand, palmitate activated c-Jun N-terminal kinase (JNK), the apoptosis effector caspase 3, and induced endoplasmic reticulum (ER) stress in mHypoE-44 cells: JNK inhibition prevented ER stress. In an attempt to avert the deleterious effects of palmitate, the neuronal cells were treated with the 5`AMP-activated protein kinase (AMPK) activator AICAR, a possible insulin sensitizer. Interestingly, AICAR attenuated JNK and caspase 3 activation, and restored insulin signaling. These findings demonstrate that insulin directly regulates NPY/AgRP neuronal cells, and that insulin and palmitate provoke neuronal insulin resistance through different mechanisms. These findings substantiate the idea that environmental factors known to trigger peripheral insulin resistance may have consequences at the level of the individual hypothalamic neuron, which may ultimately contribute to the resulting pathophysiological states of obesity and T2DM.

Endometriumkrebs ist eine der häufigsten gynäkologischen Malignomen weltweit und wird in einen Typ I eingeteilt, welcher östrogenabhängig ist, und in eine Typ-II-Östrogen-unabhängige Form. Typ I ist der häufigste Fall und kommt in etwa für 75% bis 85% aller diagnostizierten Fälle in Frage. Erhöhte Östrogenspiegel haben gezeigt, das Risiko von Gebärmutterkrebsentwicklung zu erhöhen, genauso wie Östrogen die Proliferation von Endometriumzellen stimuliert und die Apoptose hemmt. Die Insulinresistenz scheint eine zentrale Rolle in der endometrialen Karzinogenese zu spielen und darüber hinaus werden Erkrankungen mit Insulinresistenz, wie zum Beispiel das polyzystische Ovarialsyndrom (PCOS) und Adipositas, sowie Typ II-Diabetes mellitus (DM) als signifikantes Risiko angesehen, Faktoren für die Entwicklung und Progression von Typ-I-Endometrium-Krebs zu sein. Zusätzlich können PCOS-Patienten durch eine Fettleibigkeit in einem normoglykämischen Status eine unabhängige Insulin-Resistenz haben. In diesem Fall scheint die Hyperinsulinämie der fördernde Faktor zu sein, nicht nur für die Entwicklung als auch für die Tumorprogression.Aber auch erhöhte Blutzuckerspiegel tragen zum Wachstum und die Karzinogenese in Endometriumkarzinom bei und dienen als wichtige Verbindung zwischen dem beobachteten erhöhten Krebsrisiko bei Patienten mit Typ-II-DM. Die Behandlung mit einem Anti-Diabetikum, welches den Insulinspiegel senken kann, könnte einen allgemeinen Ansatz bieten gegen die Entwicklung von Krebs und zur Verringerung der Metastasierung. Das Ziel dieser Studie war es, die Wirkung einer 0,1 mM Metformin-Dosis auf das proliferative und metastatische Potential von Endometriumkrebszellen bewerten zu können, sowie die Analyse der Auswirkungen von kurz- und langfristigen Behandlungen auf intrazelluläre Signalwege der Endometriumkrebszellen.(Fortsetzung) (Fortsetzung)Ebenso soll der Zusammenhang der Entwicklung und der Progression von Krebszellen untersucht werden, wenn sie einer Umgebung mit unterschiedlichen Glucosekonzentrationen und hohen Insulinspiegeln ausgesetzt werden. Darüber hinaus ist eine endometriale dreidimensionale (3D) Cokultur zu standardisieren, für eine viabele Kultur bei 20 Tagen Kultivierung. Das proliferative Potential wurde unter Verwendung des CellTitle-Glo-Tests durchgeführt, und das metastatische Potential wurde unter Verwendung von Transwell-Migration und Invasion untersucht. Die mRNAExpression von MKI67, mTOR, NOTCH1, NOTCH3 und JAG1 Gene wurden durch real-time PCR gemessen. Die kumulative Populationsverdopplungsrate wurde durch das Replikationsverhalten einer Endometriumkrebszelllinie durchgehend von 20 Tagen nach einer Behandlungsdauer bestimmt. In allen Assays wurden die Zellen durch Medien mit normaler (5,5 mM) oder hoher (17 mM) Glucosekonzentration, sowie in verschiedenen Gruppen behandelt: Kontrolle, Insulin, Metformin und Insulin+Metformin. Das 3D-Kokulturmodell wurde unter Verwendung von endometrialen Primärzellen und einer Endometriumkrebszelllinie hergestellt, wobei die Modellkonstruktion durch Matrigel® als extrazelluläre Matrix verwendet wurde. In dieser Studie hemmte die 0,1 mM Metformin-Dosis die Insulinwirkung stark und verringerte die Fähigkeit der endometrialen Krebszelllinie, in einer hohen und normalen Glukoseumgebung zu migrieren und einzudringen.(Fortsetzung) (Fortsetzung) Auf das proliferative Potential wurde dieser Effekt nicht beobachtet, allerdings reagierte die relative Zellproliferation empfindlich auf Metformin im Bereich zwischen 1 und 5 mM, unabhängig von der vorliegenden Glucosekonzentration. In den intrazellulären molekularen Mechanismen wurde beobachtet, dass die hohe Glukosekonzentration eine optimale Umgebung für endometriale Krebszellen schafft, um einen aggressiveren Genotyp und eine Resistenz gegenüber Metformin während einer Langzeitbehandlung zu zeigen. Darüber hinaus blieb das endometriale 3DKokulturmodell über 20 Kulturtage lebensfähig. Daher zeigte sich, trotz der Endometriumkrebszellen, eine Resistenz gegenüber dem Metformin-Effekt, wenn sie einer hohen Glucoseumgebung ausgesetzt waren. Die 0,1 mM Metformin-Dosis war in der Lage, die Insulinwirkung zu hemmen und das metastatische Potential der Zellen zu verringern, was darauf hindeutet, dass Metformin klinisch in Verbindung mit Insulin wirkt, sowie die indirekten und direkten Effekte als potentieller Wirkstoff in der Krebstherapie eingesetzt werden könnten. / O câncer de endométrio é uma das neoplasias ginecológicas com maior incidência, classificado como tipo I, estrógeno dependente, e tipo II, estrógeno nãodependente. O tipo I é a forma mais comum, ocorrendo em torno de 75 – 85 % dos casos de câncer de endométrio. Altos níveis de estrogênio têm sido relacionados ao aumento do risco de desenvolvimento do câncer de endométrio, pois estimula a proliferação celular e inibe a apoptose. A resistência à insulina parece desempenhar um papel central nesta neoplasia, e as doenças associadas à resistência à insulina como obesidade, Diabetes Mellitus (DM) tipo II e Síndrome dos Ovários Policísticos (PCOS) também são consideradas fatores de risco significantes para o desenvolvimento e progressão do câncer de endométrio tipo I. Adicionalmente, pacientes com PCOS podem apresentar um quadro de resistência à insulina independente de obesidade, permanecendo em um estado glicêmico normal. Neste caso, a hiperinsulinemia isolada seria um fator tanto para a promoção, como também para a progressão do câncer. Entretanto, o aumento de níveis séricos de glicose, a hiperglicemia, também é considerada um fator independente para o desenvolvimento e progressão do câncer de endométrio sendo um elo crítico entre o aumento do risco do desenvolvimento de câncer observado em pacientes com DM tipo II Dessa forma, tratamento utilizando agentes insulino-sensibilizantes, que atuam diminuindo a resistência à insulina e consequentemente reduzindo seus níveis pode ser uma estratégia interessante para prevenir o câncer e reduzir a disseminação metastática. Os objetivos deste trabalho foram avaliar o efeito da dose de 0,1 mM de metformina sobre o potencial proliferativo e metastático das células de câncer de endométrio, assim como, avaliar o efeito do tratamento a curto e a longo prazo sobre vias de sinalização intracelular relacionadas ao desenvolvimento e progressão do câncer de endométrio quando exposta a um ambiente com diferentes concentrações de glicose e níveis elevados de insulina. Por fim, a padronização de um modelo tridimensional (3D) de cocultura de células de endométrio que permanecesse viável ao longo de 20 dias de cultivo. O potencial proliferativo foi determinado pelo método luminescente CellTitle Glo, e o potencial metastático pelo o ensaio transwell de migração e invasão. Análises de expressão do mRNA dos genes MKI67, mTOR, NOTCH1, NOTCH3 e JAG1 foram realizadas a partir da técnica de PCR em tempo real. O índice de duplicação populacional cumulativo das células determinou o comportamento de replicação da linhagem de câncer de endométrio ao longo do período de tratamento de 20 dias. Em todas os ensaios as células foram cultivadas em meio contendo concentrações normais (5,5 mM) ou altas (17 mM) de glicose, e divididas nos diferentes grupos de tratamento: controle, insulina, metformina e metformina associado a insulina. A padronização do modelo 3D de cocultura de células de endométrio foi realizado utilizando células primárias e células de linhagem de câncer de endométrio, a Matrigel® foi a matriz extracelular temporária utilizada para a construção do modelo. Neste estudo, a concentração de 0,1 mM de metformina inibiu a ação da insulina, diminuindo a habilidade de migração e invasão das células de câncer de endométrio independente da concentração de glicose presente no meio. Entretanto, este efeito não foi observado sobre o potencial proliferativo, sendo observada uma redução da proliferação das células de câncer de endométrio ao serem utilizadas concentrações maiores de metformina. Em relação aos mecanismos moleculares intracelulares, foi observado que na presença de altas concentrações de glicose as células de câncer de endométrio adquirem um genótipo mais agressivo e apresentam resistência ao efeito da metformina na dose de 0,1 mM durante o tratamento agudo. Além disso, foi possível a padronização de um modelo 3D de cocultura de células de câncer de endométrio que permanecesse viável ao longo dos 20 dias de cultivo. Contudo, apesar das células de câncer de endométrio apresentarem resistência ao efeito da metformina na presença de altas concentrações de glicose, a dose de 0,1 mM foi capaz de inibir o efeito da insulina e diminuir o potencial metastático dessas células, sugerindo que a metformina ao atuar clinicamente em combinação com seus efeitos indiretos e diretos pode ser um potencial agente adjuvante na terapia contra o câncer. / Endometrial cancer is one of the most common gynecological malignancies worldwide and is classified into a type I, which is estrogen-dependent, and a type II estrogen-independent form. The type I is the most common, accounting to 75%-85% of all cases of endometrial cancer. Elevated estrogen levels have been shown to increase the risk of endometrial cancer development, as estrogen stimulates endometrial cell proliferation and inhibits apoptosis. The insulin resistance seems to play a central role in endometrial carcinogenesis, furthermore, diseases associate with insulin resistance, as seen in polycystic ovary syndrome (PCOS), and obesity, as well as type II diabetes mellitus (DM) are considered as significant risk factors for the development and progression of type I endometrial cancer. Additionally, PCOS patients may have an insulin resistance independent of obesity remaining in a normoglycemic status. At this case, the hypeinsulinemia seems to be the promoter factor not only for the development but also for the cancer progression. However, also increased blood glucose levels are contributing to the growth and carcinogenesis in endometrial cancer and are acting as a critical link between the observed increased cancer risk in patients with type II DM. Therefore, the treatment with insulin-sensitizing agents that act through reducing insulin levels, could offer a general approach to prevent the development of cancer and reduce metastasis The aim of this study was to evaluate the effect of 0.1 mM metformin dose on the proliferative and metastatic potential of endometrial cancer cells, as well as, analyze the effects of short and long-term treatment on intracellular signaling pathways related to endometrial cancer development and progression when exposed to an environment with different glucose concentrations and high insulin levels. Additionally, the endometrial three-dimensional (3D) coculture standardization to remain viable over 20 culture days. The proliferative potential was performed by using CellTitle Glo assay, and the metastatic potential was performed by using transwell migration and invasion assay. The mRNA expression of MKI67, mTOR, NOTCH1, NOTCH3 and JAG1 genes were measured by real time PCR. The cumulative population doubling rate was evaluated to determine the replication behavior of an endometrial cancer cell line throughout 20 days of treatment period. In all assays the cells were cultured in medium containing normal (5.5 mM) or high (17 mM) glucose concentration, and treated in different groups: control, insulin,metformin or combined treatment The 3D coculture model was established by using endometrial primary cells and an endometrium cancer cell line, to the model construction Matrigel® was used as an extracellular matrix. In this study, the 0.1 mM metformin dose potently inhibited the insulin action, decreasing the ability of the endometrial cancer cell line to migrate and invade in a high and normal glucose environment. On the proliferative potential this effect was not observed, however, relative cell proliferation sensitivity to metformin was observed in the range between 1 and 5 mM regardless of the present glucose concentration. In the intracellular molecular mechanisms, it was observed that the high glucose concentration creates an optimal environment for endometrial cancer cells to exhibit a more aggressive genotype and resistance to metformin during a long-term treatment. Moreover, the endometrial 3D coculture model remained viable throughout 20 culture days. Therefore, despite of endometrial cancer cells show resistance to the metformin effect when exposed to high glucose environment, the 0.1 mM metformin dose was able to inhibit the insulin action and decrease the metastatic potential of the cells, suggesting that metformin is acting clinically in combination with indirectly and direct effects could emerge as a potential agent in cancer therapy.

Endometriumkrebs ist eine der häufigsten gynäkologischen Malignomen weltweit und wird in einen Typ I eingeteilt, welcher östrogenabhängig ist, und in eine Typ-II-Östrogen-unabhängige Form. Typ I ist der häufigste Fall und kommt in etwa für 75% bis 85% aller diagnostizierten Fälle in Frage. Erhöhte Östrogenspiegel haben gezeigt, das Risiko von Gebärmutterkrebsentwicklung zu erhöhen, genauso wie Östrogen die Proliferation von Endometriumzellen stimuliert und die Apoptose hemmt. Die Insulinresistenz scheint eine zentrale Rolle in der endometrialen Karzinogenese zu spielen und darüber hinaus werden Erkrankungen mit Insulinresistenz, wie zum Beispiel das polyzystische Ovarialsyndrom (PCOS) und Adipositas, sowie Typ II-Diabetes mellitus (DM) als signifikantes Risiko angesehen, Faktoren für die Entwicklung und Progression von Typ-I-Endometrium-Krebs zu sein. Zusätzlich können PCOS-Patienten durch eine Fettleibigkeit in einem normoglykämischen Status eine unabhängige Insulin-Resistenz haben. In diesem Fall scheint die Hyperinsulinämie der fördernde Faktor zu sein, nicht nur für die Entwicklung als auch für die Tumorprogression.Aber auch erhöhte Blutzuckerspiegel tragen zum Wachstum und die Karzinogenese in Endometriumkarzinom bei und dienen als wichtige Verbindung zwischen dem beobachteten erhöhten Krebsrisiko bei Patienten mit Typ-II-DM. Die Behandlung mit einem Anti-Diabetikum, welches den Insulinspiegel senken kann, könnte einen allgemeinen Ansatz bieten gegen die Entwicklung von Krebs und zur Verringerung der Metastasierung. Das Ziel dieser Studie war es, die Wirkung einer 0,1 mM Metformin-Dosis auf das proliferative und metastatische Potential von Endometriumkrebszellen bewerten zu können, sowie die Analyse der Auswirkungen von kurz- und langfristigen Behandlungen auf intrazelluläre Signalwege der Endometriumkrebszellen.(Fortsetzung) (Fortsetzung)Ebenso soll der Zusammenhang der Entwicklung und der Progression von Krebszellen untersucht werden, wenn sie einer Umgebung mit unterschiedlichen Glucosekonzentrationen und hohen Insulinspiegeln ausgesetzt werden. Darüber hinaus ist eine endometriale dreidimensionale (3D) Cokultur zu standardisieren, für eine viabele Kultur bei 20 Tagen Kultivierung. Das proliferative Potential wurde unter Verwendung des CellTitle-Glo-Tests durchgeführt, und das metastatische Potential wurde unter Verwendung von Transwell-Migration und Invasion untersucht. Die mRNAExpression von MKI67, mTOR, NOTCH1, NOTCH3 und JAG1 Gene wurden durch real-time PCR gemessen. Die kumulative Populationsverdopplungsrate wurde durch das Replikationsverhalten einer Endometriumkrebszelllinie durchgehend von 20 Tagen nach einer Behandlungsdauer bestimmt. In allen Assays wurden die Zellen durch Medien mit normaler (5,5 mM) oder hoher (17 mM) Glucosekonzentration, sowie in verschiedenen Gruppen behandelt: Kontrolle, Insulin, Metformin und Insulin+Metformin. Das 3D-Kokulturmodell wurde unter Verwendung von endometrialen Primärzellen und einer Endometriumkrebszelllinie hergestellt, wobei die Modellkonstruktion durch Matrigel® als extrazelluläre Matrix verwendet wurde. In dieser Studie hemmte die 0,1 mM Metformin-Dosis die Insulinwirkung stark und verringerte die Fähigkeit der endometrialen Krebszelllinie, in einer hohen und normalen Glukoseumgebung zu migrieren und einzudringen.(Fortsetzung) (Fortsetzung) Auf das proliferative Potential wurde dieser Effekt nicht beobachtet, allerdings reagierte die relative Zellproliferation empfindlich auf Metformin im Bereich zwischen 1 und 5 mM, unabhängig von der vorliegenden Glucosekonzentration. In den intrazellulären molekularen Mechanismen wurde beobachtet, dass die hohe Glukosekonzentration eine optimale Umgebung für endometriale Krebszellen schafft, um einen aggressiveren Genotyp und eine Resistenz gegenüber Metformin während einer Langzeitbehandlung zu zeigen. Darüber hinaus blieb das endometriale 3DKokulturmodell über 20 Kulturtage lebensfähig. Daher zeigte sich, trotz der Endometriumkrebszellen, eine Resistenz gegenüber dem Metformin-Effekt, wenn sie einer hohen Glucoseumgebung ausgesetzt waren. Die 0,1 mM Metformin-Dosis war in der Lage, die Insulinwirkung zu hemmen und das metastatische Potential der Zellen zu verringern, was darauf hindeutet, dass Metformin klinisch in Verbindung mit Insulin wirkt, sowie die indirekten und direkten Effekte als potentieller Wirkstoff in der Krebstherapie eingesetzt werden könnten. / O câncer de endométrio é uma das neoplasias ginecológicas com maior incidência, classificado como tipo I, estrógeno dependente, e tipo II, estrógeno nãodependente. O tipo I é a forma mais comum, ocorrendo em torno de 75 – 85 % dos casos de câncer de endométrio. Altos níveis de estrogênio têm sido relacionados ao aumento do risco de desenvolvimento do câncer de endométrio, pois estimula a proliferação celular e inibe a apoptose. A resistência à insulina parece desempenhar um papel central nesta neoplasia, e as doenças associadas à resistência à insulina como obesidade, Diabetes Mellitus (DM) tipo II e Síndrome dos Ovários Policísticos (PCOS) também são consideradas fatores de risco significantes para o desenvolvimento e progressão do câncer de endométrio tipo I. Adicionalmente, pacientes com PCOS podem apresentar um quadro de resistência à insulina independente de obesidade, permanecendo em um estado glicêmico normal. Neste caso, a hiperinsulinemia isolada seria um fator tanto para a promoção, como também para a progressão do câncer. Entretanto, o aumento de níveis séricos de glicose, a hiperglicemia, também é considerada um fator independente para o desenvolvimento e progressão do câncer de endométrio sendo um elo crítico entre o aumento do risco do desenvolvimento de câncer observado em pacientes com DM tipo II Dessa forma, tratamento utilizando agentes insulino-sensibilizantes, que atuam diminuindo a resistência à insulina e consequentemente reduzindo seus níveis pode ser uma estratégia interessante para prevenir o câncer e reduzir a disseminação metastática. Os objetivos deste trabalho foram avaliar o efeito da dose de 0,1 mM de metformina sobre o potencial proliferativo e metastático das células de câncer de endométrio, assim como, avaliar o efeito do tratamento a curto e a longo prazo sobre vias de sinalização intracelular relacionadas ao desenvolvimento e progressão do câncer de endométrio quando exposta a um ambiente com diferentes concentrações de glicose e níveis elevados de insulina. Por fim, a padronização de um modelo tridimensional (3D) de cocultura de células de endométrio que permanecesse viável ao longo de 20 dias de cultivo. O potencial proliferativo foi determinado pelo método luminescente CellTitle Glo, e o potencial metastático pelo o ensaio transwell de migração e invasão. Análises de expressão do mRNA dos genes MKI67, mTOR, NOTCH1, NOTCH3 e JAG1 foram realizadas a partir da técnica de PCR em tempo real. O índice de duplicação populacional cumulativo das células determinou o comportamento de replicação da linhagem de câncer de endométrio ao longo do período de tratamento de 20 dias. Em todas os ensaios as células foram cultivadas em meio contendo concentrações normais (5,5 mM) ou altas (17 mM) de glicose, e divididas nos diferentes grupos de tratamento: controle, insulina, metformina e metformina associado a insulina. A padronização do modelo 3D de cocultura de células de endométrio foi realizado utilizando células primárias e células de linhagem de câncer de endométrio, a Matrigel® foi a matriz extracelular temporária utilizada para a construção do modelo. Neste estudo, a concentração de 0,1 mM de metformina inibiu a ação da insulina, diminuindo a habilidade de migração e invasão das células de câncer de endométrio independente da concentração de glicose presente no meio. Entretanto, este efeito não foi observado sobre o potencial proliferativo, sendo observada uma redução da proliferação das células de câncer de endométrio ao serem utilizadas concentrações maiores de metformina. Em relação aos mecanismos moleculares intracelulares, foi observado que na presença de altas concentrações de glicose as células de câncer de endométrio adquirem um genótipo mais agressivo e apresentam resistência ao efeito da metformina na dose de 0,1 mM durante o tratamento agudo. Além disso, foi possível a padronização de um modelo 3D de cocultura de células de câncer de endométrio que permanecesse viável ao longo dos 20 dias de cultivo. Contudo, apesar das células de câncer de endométrio apresentarem resistência ao efeito da metformina na presença de altas concentrações de glicose, a dose de 0,1 mM foi capaz de inibir o efeito da insulina e diminuir o potencial metastático dessas células, sugerindo que a metformina ao atuar clinicamente em combinação com seus efeitos indiretos e diretos pode ser um potencial agente adjuvante na terapia contra o câncer. / Endometrial cancer is one of the most common gynecological malignancies worldwide and is classified into a type I, which is estrogen-dependent, and a type II estrogen-independent form. The type I is the most common, accounting to 75%-85% of all cases of endometrial cancer. Elevated estrogen levels have been shown to increase the risk of endometrial cancer development, as estrogen stimulates endometrial cell proliferation and inhibits apoptosis. The insulin resistance seems to play a central role in endometrial carcinogenesis, furthermore, diseases associate with insulin resistance, as seen in polycystic ovary syndrome (PCOS), and obesity, as well as type II diabetes mellitus (DM) are considered as significant risk factors for the development and progression of type I endometrial cancer. Additionally, PCOS patients may have an insulin resistance independent of obesity remaining in a normoglycemic status. At this case, the hypeinsulinemia seems to be the promoter factor not only for the development but also for the cancer progression. However, also increased blood glucose levels are contributing to the growth and carcinogenesis in endometrial cancer and are acting as a critical link between the observed increased cancer risk in patients with type II DM. Therefore, the treatment with insulin-sensitizing agents that act through reducing insulin levels, could offer a general approach to prevent the development of cancer and reduce metastasis The aim of this study was to evaluate the effect of 0.1 mM metformin dose on the proliferative and metastatic potential of endometrial cancer cells, as well as, analyze the effects of short and long-term treatment on intracellular signaling pathways related to endometrial cancer development and progression when exposed to an environment with different glucose concentrations and high insulin levels. Additionally, the endometrial three-dimensional (3D) coculture standardization to remain viable over 20 culture days. The proliferative potential was performed by using CellTitle Glo assay, and the metastatic potential was performed by using transwell migration and invasion assay. The mRNA expression of MKI67, mTOR, NOTCH1, NOTCH3 and JAG1 genes were measured by real time PCR. The cumulative population doubling rate was evaluated to determine the replication behavior of an endometrial cancer cell line throughout 20 days of treatment period. In all assays the cells were cultured in medium containing normal (5.5 mM) or high (17 mM) glucose concentration, and treated in different groups: control, insulin,metformin or combined treatment The 3D coculture model was established by using endometrial primary cells and an endometrium cancer cell line, to the model construction Matrigel® was used as an extracellular matrix. In this study, the 0.1 mM metformin dose potently inhibited the insulin action, decreasing the ability of the endometrial cancer cell line to migrate and invade in a high and normal glucose environment. On the proliferative potential this effect was not observed, however, relative cell proliferation sensitivity to metformin was observed in the range between 1 and 5 mM regardless of the present glucose concentration. In the intracellular molecular mechanisms, it was observed that the high glucose concentration creates an optimal environment for endometrial cancer cells to exhibit a more aggressive genotype and resistance to metformin during a long-term treatment. Moreover, the endometrial 3D coculture model remained viable throughout 20 culture days. Therefore, despite of endometrial cancer cells show resistance to the metformin effect when exposed to high glucose environment, the 0.1 mM metformin dose was able to inhibit the insulin action and decrease the metastatic potential of the cells, suggesting that metformin is acting clinically in combination with indirectly and direct effects could emerge as a potential agent in cancer therapy.

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The prevalence of childhood obesity and Type 2 Diabetes Mellitus (T2DM) has increased during recent decades. T2DM is accompanied with functional changes in the islets of Langerhans, which can be identified early in the pathogenesis. The aim of this thesis was to explore how metabolic changes caused by obesity early in life relate to islet function prior to overt T2DM. To address this, Uppsala Longitudinal Study of Childhood Obesity (ULSCO) was established (paper I). Initially, the association between palmitate and insulin secretion was investigated using a translational approach with obese and lean normoglycemic juveniles and isolated human islets (paper II). Secondly, dynamics of islet-hormones insulin and glucagon, and gut-hormones glucagon like-peptide 1 (GLP-1) and glicentin (paper III) and magnetic resonance imaging of pancreatic fat fraction (PFF) (paper IV) were studied in association to glucose tolerance and beta-cell function. Finally, a novel method of analysing shape features of oral glucose tolerance test (OGTT) curves was introduced and evaluated (paper V). Obese subjects had high prevalence of prediabetes and metabolic syndrome (MetS) (paper I). In obese pre-pubertal children with elevated palmitate levels, hyperinsulinemia was observed (paper II). In contrast, obese pubertal adolescents with similar palmitate levels showed moderate insulin levels during OGTT with delayed first phase insulin response. To explore mechanisms for these variations, isolated human islets were exposed to palmitate for different time periods in vitro. After 2 days accentuated insulin response was observed. Impaired beta-cell function and apoptosis were evident after 7 days, however. Hyperglucagonemia and disturbed GLP-1 and glicentin levels were associated with obesity and glycaemic status, with fasting glicentin being predictive of prediabetes (paper III). Furthermore, PFF was increased in obese subjects and associated to MetS and visceral adipose tissue, but not to beta-cell function (paper IV). OGTT curves were converted into geometric centres, centroids, which correlated with differences in glucose tolerance (paper V). In conclusion, the islet function in obese children was associated with elevated levels of palmitate, but not pancreatic fat. Fasting palmitate and glicentin levels, as well as centroid analyses of OGTT curves, could potentially identify obese children at risk of prediabetes and subsequent T2DM.

No description available.

No description available.