Malignant pleural mesothelioma (MPM) is an aggressive, treatment-resistant tumour. Cisplatin (cis-diamminedichloroplatinum (II)) is the best single-agent chemotherapy for MPM, but platinum-based combination therapies give the best overall response rates. However, cisplatin use is limited by resistance and severe side effects. This thesis has increased the knowledge concerning cisplatin-induced cell death in MPM by describing a novel potential therapeutic target, and three novel phenotypes of cisplatin-resistance in a human MPM cell line (P31) and its cisplatin-resistant sub-line (P31res1.2). The novel potential therapeutic target, and one of the novel phenotypes, was cisplatin-resistant pro-apoptotic BH3-only proteins. In the P31 cells, cisplatin transiently increased pro-apoptotic BH3-only proteins during 6 h of exposure. This response was almost completely abrogated in the P31res1.2 cells. De-regulated caspase activity and activation was the second novel phenotype identified. The P31res1.2 cells had earlier, possibly mitochondria-independent, caspase-3 activation, increased basal caspase-3 activity and increased basal cleavage of caspase-8 and -9. Despite these differences, 6-h equitoxic cisplatin exposures rendered 50-60% of the cells apoptotic in both cell lines. The third novel phenotype was abrogated Na+K+2Cl--cotransporter (NKCC1) activity. Although NKCC1 activity was dispensable for cisplatin-induced apoptosis, balanced potassium transport activity was essential for P31 cell survival. Finally, the survival signalling protein Protein Kinase B (PKB or Akt) isoforms α and γ were constitutively activated in a PI3K-independent manner in P31 cells. In the P31res1.2 cells, PKBα and γ activities were increased, and there was PI3K-dependent activation of PKBβ. However, this increase in PKB isoform activity was not strongly associated to the cisplatin-resistance of the P31res1.2 cells.

Homeostasis is an indispensable phenomenon in the maintenance of living organisms. Genetic defects which disrupt negative feedback processes can impact homeostatic regulation, potentially resulting in disease. To uncover the molecular mechanisms governing these and other diseases potentially related to defective homeostasis, I used the Drosophila neuromuscular junction as a model system. I characterized two potential mechanisms that regulate homeostasis within the nervous system. First, in Drosophila larval motor neurons, ligand activation of Drosophila metabotropic glutamate receptor A (DmGluRA) mediates a Phosphoinositide 3-kinase (PI3K)-dependent downregulation of neuronal activity, but the mechanism by which mGluR activates PI3K remains incompletely understood. Here, I identified Ca 2+ /Calmodulin-dependant protein kinase II (CaMKII) and the Focal adhesion kinase (DFak) as critical intermediates in the DmGluRA-dependent activation of PI3K at Drosophila motor nerve terminals. I found that transgene-induced CaMKII inhibition or the DFak CG1 null mutation each block the ability of glutamate application to activate PI3K in larval motor nerve terminals, whereas transgene-induced CaMKII activation increases PI3K activity in motor nerve terminals in a DFak-dependent manner, even in the absence of glutamate application. I conclude that the activation of PI3K by DmGluRA is mediated by CaMKII and DFak. Second, I observed that Push, a putative E3-ubiquitin ligase and Ca 2+ /Calmodulin binding protein, regulates both neurotransmitter release and retrograde signaling in the Drosophila neuromuscular junction. I found that RNAi-mediated Push inhibition in the neuron increases but, in the muscle decreases, neurotransmitter release. Similar results were obtained from RNAi knock down of PLCβ and IP3R, which mediates Ca 2+ release from the endoplasmic reticulum. I conclude that Push mediation of the ubiquitin proteasome system may be important in the regulation of PLCβ/IP3R-mediated intracellular Ca 2+ release, and that this Ca 2+ release in the neuron inhibits neurotransmitter release, but in the muscle activates neurotransmitter release via a retrograde signal.

[Truncated abstract] Reactive oxygen species (ROS) have been implicated to play a major role in many pathological conditions including heart attack and stroke. Their ability to modulate the extracellular signal-regulated protein kinase (ERK) and c-Jun Nterminal kinase (JNK) signalling pathways, thereby influencing cellular response has been well-documented. Recent studies implicate a central role for mitochondria in ERK and JNK activation by ROS although the mechanisms remained unresolved. Using Jurkat T-lymphocyte as a cell model, this study demonstrated increased mitochondrial ROS production as a result of decreased mitochondrial complex activities mediated by hydrogen peroxide treatment. This is the first study to show that mitochondria are not essential for activating ERKs, however damaged mitochondria producing ROS can be expected to cause sustained ERK activation . . . This study revealed that JNK and its upstream kinases MKK4, MKK7 and ASK1 are associated with the mitochondria. Furthermore, findings from this study imply that JNK resides in the mitochondrial matrix. This study is the first to demonstrate that mitochondrial JNK can be activated in a cell-free environment by signals originating from the mitochondria. Experimental work using isolated mitochondria demonstrated that mitochondrial JNK can be activated by ROS generated from the mitochondria themselves. Flavin-containing proteins appear to be the main sources of mitochondrial-ROS which signal through redoxsensitive proteins to activate mitochondrial JNK.

O câncer de endométrio tem incidência crescente, principalmente nos países desenvolvidos, devido ao estilo de vida moderno, aumento de casos de obesidade e diabetes, e diversos outros fatores que, em conjunto, estão tornando esta neoplasia na mais comum no trato reprodutor feminino. Ele é bastante influenciado pelo estado hormonal e por fatores reprodutivos das pacientes. Assim, é mais frequente no período pós-menopausa, quando pode ocorrer um desequilíbrio na sinalização do estrogênio. A diabetes e a obesidade são causadas, principalmente, pelo excesso de triglicerídeos e glicose circulantes, e pela resistência à insulina. A hiperglicemia leva à produção excessiva de insulina e do fator de crescimento semelhante à insulina tipo 1 (IGF1), sendo que estes hormônios são considerados antiapoptóticos e promotores da proliferação celular. Sabe-se que eles agem por vias semelhantes e que, provavelmente, o mecanismo responsável pela proliferação provocada por eles está associado à via PI3K/Akt/mTOR. Desta forma, avaliamos a expressão gênica de 92 genes na rota de sinalização do IGF1R em câncer de endométrio (n=3) e endométrio normal (n=2), através da técnica de qRT-PCR (ensaio TaqMan® Array Human IGF1R Signaling). Dentro destes genes, alguns estão envolvidos diretamente com a via PI3K/Akt/MAPK, outros estão implicados em processos como proliferação, diferenciação, tumorigênese, apoptose, resposta imune, síntese proteica, entre outros. Avaliamos, também, os níveis proteicos do receptor do fator de crescimento semelhante à insulina (IGF1R), IGF1 e receptor da insulina (IR) pela técnica de imunohistoquímica, além da funcionalidade geral dos 4 genes mais diferencialmente expressos no câncer de endométrio Observamos que, dos 92 genes, 26 foram expressos somente no grupo câncer - CACNA1H, CRK, EIF2B5, ELK1, FRAP1 (MTOR), GYS1, HRAS, IGF2, IKBKB, IKBKE, ITPR3, KRAS, NFAT5, NFATC1, NFKB1, NFKBIB, NFKBIE, PIK3CA, PIK3CB, PLCB1, PLCB2, PLCG2, PRKCZ, RELB, SHC1 e YWHAZ; 46 tiveram expressão aumentada no grupo câncer de endométrio - AKT1, AKT2, ARAF, ATF4, BAD, BRAF, CACNA1C, CALM1, CALM2, CALM3, CREB1, EIF4E, FOXO3, GSK3B, IGF1, IGF1R, IKBKG, IRS1, MAP2K1, MAP2K2, MAPK3, MEF2C, MEF2D, NFATC2, NFATC3. NFKB2, NFKBIA, NRAS, PDPK1, PIK3CD, PIK3R1, PIK3R2, PLCG1, PPP3CA, PPP3R1, PRKCI, RAF1, RAPGEF1, RELA, RPS6, RPS6KB1, SOS1, YWHAB, YWHAE, YWHAH e YWHAQ, um não apresentou expressão em nenhum dos grupos (SLC2A4) e não foi possível analisar os restantes 20 genes, pois não foram expressos em todas as amostras. Quanto à expressão das proteínas IGF1R, IGF1 e IR, todas se mostraram mais expressas no câncer de endométrio e que se encontram localizadas principalmente no citoplasma das células. Assim, este trabalho mostra que a sinalização do IGF1R pode ter participação importante na aquisição do fenótipo maligno das células endometriais, e que o aumento das moléculas efetoras desta via no câncer de endométrio provavelmente está relacionado ao seu papel mitogênico. / Endometrial cancer has a growing incidence, especially in developed countries, because of the modern lifestyle, increased cases of obesity and diabetes, and several other factors that together make this disease the most common in the female reproductive tract. Endometrial cancer is strongly influenced by the hormonal state and by the reproductive factors of the patients. Thus, it is attributed to the postmenopausal period, when estrogen signaling can be unbalanced, and consequently lead to malignant proliferative patterns. Diabetes and obesity are caused mainly by the excess of circulating triglycerides and glucose, and by insulin resistance. Hyperglycemia leads to excessive production of insulin and IGF1.These hormones are considered to have antiapoptotic effects and to promote cell proliferation. It is known that they are very similar pathways, and the mechanism responsible for this proliferation is associated with the PI3K/Akt/mTOR pathway. Thus, we evaluated the expression of 92 genes in IGF1R signaling pathway in endometrial cancer (n = 3) and normal endometrium (n = 2), using qRT-PCR (TaqMan® Array Human IGF1R Signaling test). Within these genes, some are in the PI3K/Akt/MAPK pathways, others are involved in proliferation, differentiation, tumorigenesis, apoptosis, immune response, protein synthesis, among others We also evaluated the protein levels of IGF1R, IGF1 and IR by immunohistochemistry, as well as the general functionality of the 4 most differentially expressed genes in endometrial cancer. We found that 26 genes were expressed only in endometrial cancer - CACNA1H, CRK, EIF2B5, ELK1, FRAP1 (mTOR), GYS1, HRAS, IGF2, IKBKB, IKBKE, ITPR3, KRAS, NFAT5, NFATc1, NFKB1, NFKBIB, NFKBIE, PIK3CA, PIK3CB, PLCB1, PLCB2, PLCG2, PRKCZ, RELB, SHC1 and YWHAZ; 46 had increased expression in endometrial cancer, when compared to control group - AKT1, AKT2, ARAF, ATF4, BAD, BRAF, CACNA1C, CALM1, CALM2, CALM3, CREB1, eIF4E, FOXO3, GSK3B, IGF1, IGF1R IKBKG, IRS1, MAP2K1, MAP2K2, MAPK3 , MEF2C, MEF2D, NFATC2, NFATC3. NFKB2, NFKBIA, PIK3R1, PIK3R2, PLCG1, PPP3CA, PPP3R1, PRKCI, RAF1, RAPGEF1, RELA, RPS6, RPS6KB1, SOS1, YWHAB, YWHAE, YWHAH and YWHAQ, one showed no expression in neither groups (SLC2A4) and the other 20 were not expressed in all samples, so we decided not to analyze them. As for the expression of IGF1R, IGF1 and IR proteins, all them showed increased expression in endometrial cancer and were localized in the citoplasm. Thus, this work shows that IGF1R signaling may play an important role in the acquisition of a malignant phenotype by endometrial cells, and that the increase of these effectors in endometrial cancer is related to its mitogenic effects.

O câncer de endométrio tem incidência crescente, principalmente nos países desenvolvidos, devido ao estilo de vida moderno, aumento de casos de obesidade e diabetes, e diversos outros fatores que, em conjunto, estão tornando esta neoplasia na mais comum no trato reprodutor feminino. Ele é bastante influenciado pelo estado hormonal e por fatores reprodutivos das pacientes. Assim, é mais frequente no período pós-menopausa, quando pode ocorrer um desequilíbrio na sinalização do estrogênio. A diabetes e a obesidade são causadas, principalmente, pelo excesso de triglicerídeos e glicose circulantes, e pela resistência à insulina. A hiperglicemia leva à produção excessiva de insulina e do fator de crescimento semelhante à insulina tipo 1 (IGF1), sendo que estes hormônios são considerados antiapoptóticos e promotores da proliferação celular. Sabe-se que eles agem por vias semelhantes e que, provavelmente, o mecanismo responsável pela proliferação provocada por eles está associado à via PI3K/Akt/mTOR. Desta forma, avaliamos a expressão gênica de 92 genes na rota de sinalização do IGF1R em câncer de endométrio (n=3) e endométrio normal (n=2), através da técnica de qRT-PCR (ensaio TaqMan® Array Human IGF1R Signaling). Dentro destes genes, alguns estão envolvidos diretamente com a via PI3K/Akt/MAPK, outros estão implicados em processos como proliferação, diferenciação, tumorigênese, apoptose, resposta imune, síntese proteica, entre outros. Avaliamos, também, os níveis proteicos do receptor do fator de crescimento semelhante à insulina (IGF1R), IGF1 e receptor da insulina (IR) pela técnica de imunohistoquímica, além da funcionalidade geral dos 4 genes mais diferencialmente expressos no câncer de endométrio Observamos que, dos 92 genes, 26 foram expressos somente no grupo câncer - CACNA1H, CRK, EIF2B5, ELK1, FRAP1 (MTOR), GYS1, HRAS, IGF2, IKBKB, IKBKE, ITPR3, KRAS, NFAT5, NFATC1, NFKB1, NFKBIB, NFKBIE, PIK3CA, PIK3CB, PLCB1, PLCB2, PLCG2, PRKCZ, RELB, SHC1 e YWHAZ; 46 tiveram expressão aumentada no grupo câncer de endométrio - AKT1, AKT2, ARAF, ATF4, BAD, BRAF, CACNA1C, CALM1, CALM2, CALM3, CREB1, EIF4E, FOXO3, GSK3B, IGF1, IGF1R, IKBKG, IRS1, MAP2K1, MAP2K2, MAPK3, MEF2C, MEF2D, NFATC2, NFATC3. NFKB2, NFKBIA, NRAS, PDPK1, PIK3CD, PIK3R1, PIK3R2, PLCG1, PPP3CA, PPP3R1, PRKCI, RAF1, RAPGEF1, RELA, RPS6, RPS6KB1, SOS1, YWHAB, YWHAE, YWHAH e YWHAQ, um não apresentou expressão em nenhum dos grupos (SLC2A4) e não foi possível analisar os restantes 20 genes, pois não foram expressos em todas as amostras. Quanto à expressão das proteínas IGF1R, IGF1 e IR, todas se mostraram mais expressas no câncer de endométrio e que se encontram localizadas principalmente no citoplasma das células. Assim, este trabalho mostra que a sinalização do IGF1R pode ter participação importante na aquisição do fenótipo maligno das células endometriais, e que o aumento das moléculas efetoras desta via no câncer de endométrio provavelmente está relacionado ao seu papel mitogênico. / Endometrial cancer has a growing incidence, especially in developed countries, because of the modern lifestyle, increased cases of obesity and diabetes, and several other factors that together make this disease the most common in the female reproductive tract. Endometrial cancer is strongly influenced by the hormonal state and by the reproductive factors of the patients. Thus, it is attributed to the postmenopausal period, when estrogen signaling can be unbalanced, and consequently lead to malignant proliferative patterns. Diabetes and obesity are caused mainly by the excess of circulating triglycerides and glucose, and by insulin resistance. Hyperglycemia leads to excessive production of insulin and IGF1.These hormones are considered to have antiapoptotic effects and to promote cell proliferation. It is known that they are very similar pathways, and the mechanism responsible for this proliferation is associated with the PI3K/Akt/mTOR pathway. Thus, we evaluated the expression of 92 genes in IGF1R signaling pathway in endometrial cancer (n = 3) and normal endometrium (n = 2), using qRT-PCR (TaqMan® Array Human IGF1R Signaling test). Within these genes, some are in the PI3K/Akt/MAPK pathways, others are involved in proliferation, differentiation, tumorigenesis, apoptosis, immune response, protein synthesis, among others We also evaluated the protein levels of IGF1R, IGF1 and IR by immunohistochemistry, as well as the general functionality of the 4 most differentially expressed genes in endometrial cancer. We found that 26 genes were expressed only in endometrial cancer - CACNA1H, CRK, EIF2B5, ELK1, FRAP1 (mTOR), GYS1, HRAS, IGF2, IKBKB, IKBKE, ITPR3, KRAS, NFAT5, NFATc1, NFKB1, NFKBIB, NFKBIE, PIK3CA, PIK3CB, PLCB1, PLCB2, PLCG2, PRKCZ, RELB, SHC1 and YWHAZ; 46 had increased expression in endometrial cancer, when compared to control group - AKT1, AKT2, ARAF, ATF4, BAD, BRAF, CACNA1C, CALM1, CALM2, CALM3, CREB1, eIF4E, FOXO3, GSK3B, IGF1, IGF1R IKBKG, IRS1, MAP2K1, MAP2K2, MAPK3 , MEF2C, MEF2D, NFATC2, NFATC3. NFKB2, NFKBIA, PIK3R1, PIK3R2, PLCG1, PPP3CA, PPP3R1, PRKCI, RAF1, RAPGEF1, RELA, RPS6, RPS6KB1, SOS1, YWHAB, YWHAE, YWHAH and YWHAQ, one showed no expression in neither groups (SLC2A4) and the other 20 were not expressed in all samples, so we decided not to analyze them. As for the expression of IGF1R, IGF1 and IR proteins, all them showed increased expression in endometrial cancer and were localized in the citoplasm. Thus, this work shows that IGF1R signaling may play an important role in the acquisition of a malignant phenotype by endometrial cells, and that the increase of these effectors in endometrial cancer is related to its mitogenic effects.

Therapy resistance of malignant cells represents the main reason responsible for the failure of cancer therapy. The growth of malignant cells at primary tumour sites but most importantly the dissemination of tumour cells and their growth at secondary sites, are the main reasons why patients eventually succumb to the disease. Even novel immune-based therapies find their limitation in most tumour types. The therapy resistance is mediated by the tumour cells but also by other cellular components of the tumour microenvironment. Understanding the tumour cells mechanisms and the tumour microenvironment features responsible for therapy resistance enables the development of novel therapeutic strategies. Here, we show that ionizing irradiation, 5-azacytidine, and IFNγ treatments induced expression of suprabasin (SBSN) and therapy-resistant low-adherent phenotype in cancer cells. Knockdown of SBSN resulted in suppression of the phenotype. Next, we identified aberrantly elevated SBSN in the bone marrow of a subgroup of myelodysplastic syndromes (MDS) patients. SBSN was expressed by myeloid-derived suppressor cells (MDSCs) and showed significant anti-correlation with T cell abundance and CCL2 levels, hence promises a prognostic value in clinical use. We compiled the most of the relevant knowledge of SBSN...

Les mécanismes adhésifs jouent un rôle crucial en biologie. Les cadhérines classiques constituent une des principales familles d'adhésion cellulaire dépendante du calcium. Ces glycoprotéines transmembranaires sont impliquées dans des interactions principalement homophiles. Ces interactions régulent des voies de signalisation impliquées dans de nombreux phénomènes biologiques. Cette thèse porte sur l'étude comparative des dynamiques d'interactions des cadhérines E- et -11, prototypes respectivement des cadhérines classiques de type I et II. Le ciblage d'acides aminés particuliers de l'interface adhésive nous a permis de montrer que pour les cadhérines de type I, l'échange de brin avec le Trp2 ont un rôle clé ; pour les types II un mécanisme différent intervient. Nous avons aussi développé une chimie innovante pour contrôler l'immobilisation orientée et covalente de protéines. Enfin une revue décrit une étude de l'activation de voies de signalisation par engagement des cadhérines. / Cell adhesion receptors of the classical cadherin family are involved in Ca2+-dependent homophilic interactions. In order to dissect the molecular mechanisms of cadherin-based cellcell adhesion, this Ph.D. thesis describes a comparative dynamic study of interactions between cadherins E- & -11, chosen as classical type I and II cadherins prototypes respectively. Modifications of particular residues in the E-cadherin adhesive interface showed that the ?-strand exchange with its Trp2 had a prominent feature; for type II cadherins, a different mechanism was described involving a larger domain swapping. We then developed a new protocol for immobilizing proteins in an orientated and covalent manner on surfaces. These interactions regulate signalization pathways in various biological processes. Studies describing Stat3 activation through direct cadherin engagement are reviewed.

Therapy resistance of malignant cells represents the main reason responsible for the failure of cancer therapy. The growth of malignant cells at primary tumour sites but most importantly the dissemination of tumour cells and their growth at secondary sites, are the main reasons why patients eventually succumb to the disease. Even novel immune-based therapies find their limitation in most tumour types. The therapy resistance is mediated by the tumour cells but also by other cellular components of the tumour microenvironment. Understanding the tumour cells mechanisms and the tumour microenvironment features responsible for therapy resistance enables the development of novel therapeutic strategies. Here, we show that ionizing irradiation, 5-azacytidine, and IFNγ treatments induced expression of suprabasin (SBSN) and therapy-resistant low-adherent phenotype in cancer cells. Knockdown of SBSN resulted in suppression of the phenotype. Next, we identified aberrantly elevated SBSN in the bone marrow of a subgroup of myelodysplastic syndromes (MDS) patients. SBSN was expressed by myeloid-derived suppressor cells (MDSCs) and showed significant anti-correlation with T cell abundance and CCL2 levels, hence promises a prognostic value in clinical use. We compiled the most of the relevant knowledge of SBSN...

Les récepteurs métabotropiques au glutamate (mGluRs) jouent un rôle important dans la régulation de la neurotransmission excitatrice. Les mGluRs du groupe III (mGluR4, 7 et 8), sont connus pour agir en tant qu’autorécepteurs, diminuant la libération vésiculaire de glutamate. Ces récepteurs couplés aux protéines G ont une vaste distribution cérébrale, et sont ainsi souvent retrouvés au sein des mêmes structures, au niveau présynaptique, (excepté les mGluR6 uniquement présents au niveau postysnaptique dans la rétine). mGluR4 est très fortement exprimé dans le cortex cérébelleux, et plus précisément au sein des zones actives des terminaisons présynaptiques de l’une des deux afférences excitatrices, les fibres parallèles, où ils représentent les seuls mGluRs du groupe III fonctionnels, ce qui fait de cette structure un modèle idéal pour l’étude de ces récepteurs. Au cours de ce travail de thèse, à l’aide d’enregistrements électrophysiologiques (Patch-Clamp) et de mesures optiques des influx calciques présynaptiques (fluorométrie), nous nous sommes intéressé aux mécanismes d’action des mGluR4 aux synapses fibres parallèles – interneurones de la couche moléculaire, mais aussi fibres parallèles – cellule de Purkinje. Nous montrons que les mGluR4 inhibent les canaux calciques voltage-dépendants par une voie Gq/PLC/PKC-dépendante, et que ces récepteurs mettent également en jeu des mécanismes parallèles moins dépendants du calcium reposant sur des interactions plus directes avec des protéines impliquées dans les processus d’exocytose.En parallèle, nous avons également contribué à la caractérisation de deux nouveaux outils pharmacologiques (agonistes orthostériques) sélectifs pour mGluR4, dont le manque actuel constitue une limite majeure à l’étude de ces récepteurs dans nombre de structures cérébrales où ils sont exprimés. / Glutamate metabotropic receptors (mGluRs) play an important role in the regulation of excitatory neurotransmission. Group III mGluRs, namely mGluR4, 7 and 8, are known to act as autoreceptors, decreasing the vesicular release of glutamate. These G-Protein Coupled Receptors are widely distributed through the brain, and thus are often localised in the same structures, presynaptically, except for mGluR6 only present postsynaptically in the retina. However, mGluR4 are the most highly expressed in the cerebellar cortex, and more precisely in the active zones of the presynaptic terminals of one of the two excitatory afferent inputs, the parallel fibres, where they are the only group III mGluR functional, turning this structure into an ideal model to study these receptors. In this work, led through electrophysiological (Patch-Clamp) recordings and optical dynamic calcium (fluorometry) measurements, we investigated the mechanisms of action of mGluR4 at both parallel fibre – Purkinje cell synapses and parallel fibre – molecular layer interneuron synapses. We show that activation of mGluR4 inhibits voltage-gated calcium channels by way of a Gq/PLC/PKC-dependent pathway, and that activation of these receptors reduces glutamate release through a complementary mechanism, a more direct interaction with exocytosis proteins. In addition, we also contributed to the characterization of two new pharmacological tools (orthosteric agonists) selective for mGluR4, which lack constitutes a major limit to the study of these receptors throughout the brain.

Insulin and insulin-like growth factors (IGF-1 and -2) together with their receptors take part in a complex system, which affects both basal metabolism of carbohydrates, lipids and proteins as well as cell growth, proliferation, differentiation and apoptosis. Defects in action of insulin or IGFs can lead to serious diseases such as diabetes or cancer. Both of these disorders represent nowadays one of the biggest health threats to the world's population. Insulin and IGFs induce different biological effects through their cognate receptors; two isoforms of the insulin receptor (IR-A and IR-B) and the receptor for IGF-1 (IGF-1R). These receptors bind insulin and IGFs with different affinities and induce different but partially overlapping signalling events leading towards metabolic (especially insulin) or mitogenic responses (IGFs and insulin). To understand the mechanism of action of insulin and IGFs it is important to specify which structural domains of these hormones are responsible for binding to the receptors and exerting specific effects. One region that is missing in insulin is the D-domain of IGF-1 and -2. For this reason, we decided to prepare insulin analogues with the A-chain extended by either the whole D-domain of IGF-1 or IGF-2, or by fragments of the IGF-1 D-domain in order to define the...