The development of targeted therapy has contributed tremendously to the treatment of patients with cancer. The use of highly specific affinity proteins to target cancer cells has become a standard in treatment strategies for several different cancers. In light of this, many cancer cell markers are investigated for their potential use in diagnostics and therapy. One such marker is the human epidermal growth factor receptor 3, HER3. It has been established as an important contributor to many cancer types. The function of HER3 is to relay cell growth signals from outside of the cell to the inside. Interfering with- and inhibit- ing the function of HER3 has emerged as an interesting strategy for cancer therapeutics. The studies presented in this thesis aim to target HER3 with small, engineered affinity domain proteins for therapeutic purposes. Monomeric affibody molecules have previously been engineered to bind and inhibit HER3 in vitro. Due to the relatively low expression of HER3, an increase in valency appears promising to strengthen the therapeutic potential. Affibody molecules targeting the receptor were thus linked to form bivalent and bispecific constructs and evaluated both in vitro and in vivo. In the first study of this thesis affibody molecules specific for HER3 and HER2 were fused to an albumin binding domain to form bivalent and bispecific construct. The constructs inhibited ligand-induced receptor phos- phorylation of both HER2 and HER3 more efficiently than monomeric affibody molecules. A second approach to enhance the potential of affibody molecules in tumor targeting is described in the second study, where monomeric HER3-binding affibody molecules were engineered to increase their affinity for HER3. The resulting variants showed a 20-fold in- creased affinity and higher capacity to inhibit cancer cell growth. Combining the findings of the first two studies, the third study describes the evaluation of a HER3-targeting bivalent affibody construct for potential application as a therapeutic. Here, the bivalent construct inhibited cancer cell growth in vitro and was found to slow down tumor growth in mice, while being well tolerated and showing no visible toxicity. The fourth study built upon these findings and compares a very similar bivalent construct to the clinically-investigated HER3-specific monoclonal antibody seribantumab. The affibody construct showed very comparable efficacy with the antibody in terms of decreasing tumor growth rate and ex- tending mouse survival. Collectively, these works describe for the first time the use of alternative affinity protein constructs with therapeutic potential targeting HER3. / <p>QC 20170330</p>

Dissertation (Ph.D.)--University of South Florida, 2007. / Title from PDF of title page. Document formatted into pages; contains 154 pages. Includes vita. Includes bibliographical references.

Growth factor receptors have significant effects on various normal function of body such as cell proliferation, differentiation and apoptosis. They are also involved in neuronal function and dysfunction, cardiovascular diseases, and malignancies. Recently, multiple G protein-coupled receptors (GPCRs) have been shown to transactivate receptor tyrosine kinases (RTKs). Since both classes of receptors have complicated downstream cascades individually, understanding the signaling differences between GPCR-induced growth factor receptor transactivation and direct ligand activation is an important challenge. To clarifying this phenomenon we investigated the phosphorylation profile and downstream effectors of ligand-activated vs. transactivated PDGF?? receptors. Dopamine receptors (one of the receptors of the GPCRs family) were used to compare the PDGF?? receptor phosphorylation and activity during direct activation and transactivation. Dose-response and time-course data between these two stimuli were evaluated. Furthermore, the phosphorylation site profiles and the intracellular signaling pathways of PDGF?? receptor after direct activation and transactivation were examined. In addition, possible synergic effects between transactivation and direct activation were explored. The results of this project showed that the phosphorylation profile and downstream effectors of ligand activated receptors versus transactivated receptors are different. Our data indicated that transactivation-induced pathways are more involved in survival and proliferation effects compared to ligand activation. This research answered basic questions about transactivation phenomena and proposes that these transactivation pathways could be exploited as a therapeutic approach for neurodegenerative diseases.

Dissertation (Ph.D.)--University of South Florida, 2007. / Includes vita. Includes bibliographical references (leaves 123-154). Also available online.

No / Activation of fibroblast growth factor receptors (FGFR) is a common oncogenic event. Little is known about the determinants of sensitivity to FGFR inhibition and how these may vary between different oncogenic FGFRs. Using parallel RNA interference (RNAi) genetic screens, we show that the EGF receptor (EGFR) limits sensitivity to FGFR inhibition in FGFR3-mutant and -translocated cell lines, but not in other FGFR-driven cell lines. We also identify two distinct mechanisms through which EGFR limits sensitivity. In partially FGFR3-dependent lines, inhibition of FGFR3 results in transient downregulation of mitogen-activated protein kinase signaling that is rescued by rapid upregulation of EGFR signaling. In cell lines that are intrinsically resistant to FGFR inhibition, EGFR dominates signaling via repression of FGFR3, with EGFR inhibition rescued by delayed upregulation of FGFR3 expression. Importantly, combinations of FGFR and EGFR inhibitors overcome these resistance mechanisms in vitro and in vivo. Our results illustrate the power of parallel RNAi screens in identifying common resistance mechanisms to targeted therapies. SIGNIFICANCE: Our data identify a novel therapeutic approach to the treatment of FGFR3-mutant cancer, emphasizing the potential of combination approaches targeting both FGFR3 and EGFR. Our data extend the role of EGFR in mediating resistance to inhibitors targeting a mutant oncogene, showing that EGFR signaling can repress mutant FGFR3 to induce intrinsic resistance to FGFR targeting.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

No description available.

Thesis evaluated by: Dr. Rémy Sauvé, Dr. Puttaswamy Manjunath and Dr. Madhu Anand-Srivastava. Thank you for all your help. / L’hypertension est associée au remodelage vasculaire dû à l’hyperprolifération et l’hypertrophie des cellules musculaires lisses vasculaires (CMLVs). Nous avons démontré par le passé l’implication de l’expression élevée des protéines Gqα et PLCβ1 dans les CMLVs de rats spontanément hypertendus (RSH) âgés de 16 semaines. Le C-ANP4-23 est un agoniste du récepteur au peptide natriurétique de type C (NPR-C) qui possède la capacité d’inhiber la synthèse de protéines en réponse aux peptides vasoactifs dans les CMLVs. Cette étude a eu pour but d’examiner si le C-ANP4-23 pouvait atténuer l’hypertrophie dans un modèle de rat souffrant d’hypertrophie cardiaque et d’explorer les mécanismes responsables de cette inhibition. Pour ce faire, des CMLVs aortiques de RSH âgés de 16 semaines ont été utilisées. Le taux de synthèse de protéines, un marqueur d’hypertrophie, a été déterminé par l’incorporation de (3H)leucine et l’expression des protéines a été déterminée par la technique d’immunobuvardage de type Western. Le volume cellulaire a été estimé par imagerie confocale tridimensionnelle. Le taux de synthèse de protéines et le volume cellulaire étaient considérablement accrus dans les CMLVs des RSH comparativement aux rats WKY et ont été largement atténués par le traitement au C-ANP4-23. De plus, le traitement au C-ANP4-23 a normalisé l’expression élevée du récepteur AT1 et des protéines Gqα et PLCβ1, des niveaux intracellulaires d’anions superoxide (O2-), de l’activité de la NADPH (de l’anglais nicotinamide adenine dinucleotide phosphate) oxydase, ainsi que l’expression des protéines Nox4 et de p47phox dans les CMLVs des RSH. En outre, le C-ANP4-23 a réduit l’activation des récepteurs à L’EGF (de l’anglais epidermal growth factor), au PDGF (de l’anglais platelet-derived growth factor), et à l’IGF-1 (de l’anglais insulin-like growth factor 1). Le C-ANP4-23 a également atténué la phosphorylation des ERK1/2 (de l’anglais extracellular regulated kinase1/2), AKT et c-Src. Ces résultats indiquent que l’activation du NPR-C par C-ANP4-23 a atténué l’hypertrophie des CMLVs par sa capacité à diminuer la surexpression du récepteur AT1, l’expression élevée des protéines Gqα/PLCβ1, le stress oxydatif accru, l’activation augmentée des facteurs de croissance et l’augmentation de la phosphorylation des voies de signalisation MAPK/AKT. Ainsi, ces travaux suggèrent que le C-ANP4-23 peut être utilisé comme agent thérapeutique pour le traitement des complications vasculaires associées à l’hypertension et à l’athérosclérose. / Hypertension is associated with vascular remodelling due to hyperproliferation and hypertrophy of vascular smooth muscle cells (VSMCs). We earlier showed the implication of enhanced expression of Gqα and PLCβ1 proteins in VSMCs from 16- week-old spontaneously hypertensive rats (SHR). The present study was undertaken to investigate whether C-ANP4-23, a natriuretic peptide receptor-C (NPR-C) agonist that has been shown to inhibit vasoactive peptide-induced enhanced protein synthesis in VSMCs, could attenuate VSMC hypertrophy in rat models of cardiac hypertrophy and to explore the underlying mechanisms contributing to this inhibition. For these studies, aortic VSMCs from 16-week-old SHR were used. The protein synthesis, a marker of hypertrophy, was determined by (3H)leucine incorporation and the expression of proteins was determined by Western blotting. Cell volume was determined by three-dimensional confocal imaging. The protein synthesis was significantly enhanced in VSMC from SHR as compared to WKY and C-ANP4-23 treatment attenuated the enhanced protein synthesis to WKY control levels. In addition, the enhanced expression of the AT1 receptor as well as Gqα and PLCβ1 proteins, enhanced levels of superoxide anion (O2 -), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, as well as the increased expressions of NADPH oxidase 4 (Nox4) and p47phox exhibited by VSMC from SHR were all attenuated by C-ANP4-23 treatment. Furthermore, C-ANP4-23 also attenuated the enhanced activation of epidermal growth factor receptor (EGF-R), platelet-derived growth factor receptor (PDGF-R), insulin-like growth factor 1 receptor (IGF-1R) and the enhanced phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), AKT and c-Src. These results indicate that C-ANP4-23, via the activation of NPR-C, attenuates VSMC hypertrophy through its ability to decrease the overexpression of the AT1 receptor and Gqα/PLCβ1 proteins, the enhanced oxidative stress, the increased activation of growth factors and the enhanced phosphorylation of the MAPK/AKT signalling pathway. Thus, it can be suggested that C-ANP4-23, an activator of NPR-C, may be used as a therapeutic agent for the treatment of vascular complications associated with hypertension and atherosclerosis.

Introdução: O objetivo foi avaliar a expressão de algumas proteínas no endométrio durante a fase lútea do ciclo menstrual de mulheres férteis e inférteis, por meio imunoistoquímica de micro-arranjos teciduais (TMA). Métodos: Analisou-se a expressão de dez proteínas em 52 amostras de endométrio obtidas nas fases lútea inicial, intermediária (janela de implantação) e final. Resultados: As proteínas, fator inibidor de leucemia (LIF), fator de crescimento insulinóide tipo 1 (IGF-1), receptor de progesterona (PR), claudina-4, receptor de fator de crescimento vascular endotelial 3 (VEGFR-3) e citoqueratina 7 (CK-7) mostraram-se expressas no endométrio nas fases lútea inicial, intermediária e final. A proteína morfogenética óssea 4 (BMP-4) expressou-se no endométrio nas fases lútea inicial e intermediária. As proteínas citoqueratina 17 (CK-17), substância solúvel 100 (S100) e calretinina não se expressaram no endométrio durante os três períodos avaliados. Houve correlação entre as expressões protéicas de LIF, IGF-1 e PR. As proteínas LIF e BMP-4 foram diferencialmente expressos no endométrio nas fases lútea inicial, intermediária e final. As proteínas claudina-4 e PR não se expressam simultâneamente no endométrio durante a fase lútea. Conclusão: Baseados nos resultados deste estudo podemos sugerir que a presença das proteínas LIF, IGF-1 e PR durante a janela implantacional teria relevância como preditor do adequado desenvolvimento do endométrio. / Introduction: The objective of this study was to evaluate endometrial protein expressions from fertile and infertile women during the luteal phase of the menstrual cycle by immunohistochemistry in tissue microarrays (TMA). Method: The expression of ten proteins obtained from 52 endometrial samples in the initial, mid (window of implantation) and late (premenstrual) phases of the menstrual cycle were evaluated. Results: The proteins leukemia inhibitory factor (LIF), insulin like growth factor 1 (IGF-1), progesterone receptor (PR), claudin-4, vascular endothelial growth factor receptor 3 (VEGFR-3), and cytokeratin 7 (CK-7) were expressed in the endometrium in the three intervals of the luteal phase. Endometrial expression of the morphogenetic bone protein 4 (BMP-4) occurred during the initial and mid luteal phases. Cytokeratin 17, substance 100 and calretinin were not expressed in the luteal phase. There were positive correlations among endometrial expressions of LIF, IGF- 1, and PR. LIF and BMP-4 were differently expressed in the initial, mid and late phases of the luteal phase. Claudin-4 and PR did not express simultaneously during the different intervals of the luteal phase. Conclusion: These findings suggest that positively correlated endometrial expressions of LIF, IGF-1 and PR at the window of implantation could characterize an adequately developed and receptive endometrium.

Introdução: O objetivo foi avaliar a expressão de algumas proteínas no endométrio durante a fase lútea do ciclo menstrual de mulheres férteis e inférteis, por meio imunoistoquímica de micro-arranjos teciduais (TMA). Métodos: Analisou-se a expressão de dez proteínas em 52 amostras de endométrio obtidas nas fases lútea inicial, intermediária (janela de implantação) e final. Resultados: As proteínas, fator inibidor de leucemia (LIF), fator de crescimento insulinóide tipo 1 (IGF-1), receptor de progesterona (PR), claudina-4, receptor de fator de crescimento vascular endotelial 3 (VEGFR-3) e citoqueratina 7 (CK-7) mostraram-se expressas no endométrio nas fases lútea inicial, intermediária e final. A proteína morfogenética óssea 4 (BMP-4) expressou-se no endométrio nas fases lútea inicial e intermediária. As proteínas citoqueratina 17 (CK-17), substância solúvel 100 (S100) e calretinina não se expressaram no endométrio durante os três períodos avaliados. Houve correlação entre as expressões protéicas de LIF, IGF-1 e PR. As proteínas LIF e BMP-4 foram diferencialmente expressos no endométrio nas fases lútea inicial, intermediária e final. As proteínas claudina-4 e PR não se expressam simultâneamente no endométrio durante a fase lútea. Conclusão: Baseados nos resultados deste estudo podemos sugerir que a presença das proteínas LIF, IGF-1 e PR durante a janela implantacional teria relevância como preditor do adequado desenvolvimento do endométrio. / Introduction: The objective of this study was to evaluate endometrial protein expressions from fertile and infertile women during the luteal phase of the menstrual cycle by immunohistochemistry in tissue microarrays (TMA). Method: The expression of ten proteins obtained from 52 endometrial samples in the initial, mid (window of implantation) and late (premenstrual) phases of the menstrual cycle were evaluated. Results: The proteins leukemia inhibitory factor (LIF), insulin like growth factor 1 (IGF-1), progesterone receptor (PR), claudin-4, vascular endothelial growth factor receptor 3 (VEGFR-3), and cytokeratin 7 (CK-7) were expressed in the endometrium in the three intervals of the luteal phase. Endometrial expression of the morphogenetic bone protein 4 (BMP-4) occurred during the initial and mid luteal phases. Cytokeratin 17, substance 100 and calretinin were not expressed in the luteal phase. There were positive correlations among endometrial expressions of LIF, IGF- 1, and PR. LIF and BMP-4 were differently expressed in the initial, mid and late phases of the luteal phase. Claudin-4 and PR did not express simultaneously during the different intervals of the luteal phase. Conclusion: These findings suggest that positively correlated endometrial expressions of LIF, IGF-1 and PR at the window of implantation could characterize an adequately developed and receptive endometrium.