O gênero Leishmania apresenta espécies capazes de desenvolver doenças de grande importância para a saúde pública, as leishmanioses, que apresentam prevalência mundial de 12 milhões de pessoas. Quando os parasitos entram em contato com o hospedeiro humano passam por um processo de metaciclogênese adquirindo capacidade de interagir com os macrófagos. Inúmeras atividades biológicas são desencadeadas pela ativação de sistemas de transdução de sinais, onde as proteínas cinases e fosfatases desempenham papel fundamental. A proteína cinase CK2 parece estar presente em todas as células eucarióticas (núcleo, citoplasma e superfície). É caracterizada como enzima serina/treonina cinase, embora também seja capaz de fosforilar resíduos de tirosina em suas proteínas-alvo. No presente trabalho, demonstramos que o principal inibidor da CK2, TBB, foi capaz de inibir o crescimento de formas promastigotas de L. donovani e mostrou um mecanismo de ação irreversível, entretanto não foi capaz de induzir apoptose nas formas promastigotas de L. donovani. O pré-tratamento dos parasitos e macrófagos, assim como a adição do TBB durante o processo de infecção induziram uma redução significativa no número de amastigotas por macrófagos possivelmente pelo mecanismo de morte celular programada demosntrada pela técnica do TUNEL. O tratamento de macrófagos com TBB não induziram o aumento de óxido nítrico. Ensaios de imunofluorescência demonstraram a presença de CK2α em promastigotas. Macrófagos não infectados demonstraram pouca marcação para CK2α. Após a interação, a enzima mostrou-se distribuída preferencialmente na periferia dos macrófagos. Os dados do trabalho sugerem que a CK2 é uma importante enzima para a atividade biológica da Leishmania donovani, tendo seu estudo importante relevância para a descoberta de novos alvos terapêuticos. / The genus Leishmania contains multiple species that are responsible for a group of diseases, leishmaniasis. Current estimates suggest that 12 million people are infected. When parasites enter a human host, they undergo metacyclogenesis and acquire the ability to interact with macrophages. This interaction activites signal transduction pathways inducing numerous biological activities, including protein kinase CK2. CK2 has been observed in all eukaryotic cells residing in the nucleus, the cytoplasm and on the cell surface. It appears to have an essential function and recognizes serine/threonine or tyrosine residues in target proteins for phosphorylation. In the present study, we demonstrate that the treatment of L. donovani promastigotes with TBB resulted in inhibition of cell growth and showed an irreversible mechanism of action, however was not able to induce apoptosis in L. donovani promastigotes. The pre-treatment of promastigotes and macrophages, as well as the addition of TBB during infection induced a significant reduction in the number of amastigotes per macrophages, possibly via the mechanism of programmed cell death showed by TUNEL technique. Treatment of macrophages with TBB did not induce the increase of nitric oxide. Immunofluorescence assays demonstrated the presence of CK2α distributed throughout the surface the promastigotes. Uninfected macrophages showed little to no CK2α. After initiating the interaction of parasites with macrophages, CK2α was observed distributed preferentially in the nucleus of macrophages. Job data suggest that CK2 is an important enzyme for the biological activity of Leishmania donovani, and its study important relevance to the discovery of new therapeutic targets.

O gênero Leishmania apresenta espécies capazes de desenvolver doenças de grande importância para a saúde pública, as leishmanioses, que apresentam prevalência mundial de 12 milhões de pessoas. Quando os parasitos entram em contato com o hospedeiro humano passam por um processo de metaciclogênese adquirindo capacidade de interagir com os macrófagos. Inúmeras atividades biológicas são desencadeadas pela ativação de sistemas de transdução de sinais, onde as proteínas cinases e fosfatases desempenham papel fundamental. A proteína cinase CK2 parece estar presente em todas as células eucarióticas (núcleo, citoplasma e superfície). É caracterizada como enzima serina/treonina cinase, embora também seja capaz de fosforilar resíduos de tirosina em suas proteínas-alvo. No presente trabalho, demonstramos que o principal inibidor da CK2, TBB, foi capaz de inibir o crescimento de formas promastigotas de L. donovani e mostrou um mecanismo de ação irreversível, entretanto não foi capaz de induzir apoptose nas formas promastigotas de L. donovani. O pré-tratamento dos parasitos e macrófagos, assim como a adição do TBB durante o processo de infecção induziram uma redução significativa no número de amastigotas por macrófagos possivelmente pelo mecanismo de morte celular programada demosntrada pela técnica do TUNEL. O tratamento de macrófagos com TBB não induziram o aumento de óxido nítrico. Ensaios de imunofluorescência demonstraram a presença de CK2α em promastigotas. Macrófagos não infectados demonstraram pouca marcação para CK2α. Após a interação, a enzima mostrou-se distribuída preferencialmente na periferia dos macrófagos. Os dados do trabalho sugerem que a CK2 é uma importante enzima para a atividade biológica da Leishmania donovani, tendo seu estudo importante relevância para a descoberta de novos alvos terapêuticos. / The genus Leishmania contains multiple species that are responsible for a group of diseases, leishmaniasis. Current estimates suggest that 12 million people are infected. When parasites enter a human host, they undergo metacyclogenesis and acquire the ability to interact with macrophages. This interaction activites signal transduction pathways inducing numerous biological activities, including protein kinase CK2. CK2 has been observed in all eukaryotic cells residing in the nucleus, the cytoplasm and on the cell surface. It appears to have an essential function and recognizes serine/threonine or tyrosine residues in target proteins for phosphorylation. In the present study, we demonstrate that the treatment of L. donovani promastigotes with TBB resulted in inhibition of cell growth and showed an irreversible mechanism of action, however was not able to induce apoptosis in L. donovani promastigotes. The pre-treatment of promastigotes and macrophages, as well as the addition of TBB during infection induced a significant reduction in the number of amastigotes per macrophages, possibly via the mechanism of programmed cell death showed by TUNEL technique. Treatment of macrophages with TBB did not induce the increase of nitric oxide. Immunofluorescence assays demonstrated the presence of CK2α distributed throughout the surface the promastigotes. Uninfected macrophages showed little to no CK2α. After initiating the interaction of parasites with macrophages, CK2α was observed distributed preferentially in the nucleus of macrophages. Job data suggest that CK2 is an important enzyme for the biological activity of Leishmania donovani, and its study important relevance to the discovery of new therapeutic targets.

L’inhibition de protéines kinases constitue une voie pleine de promesses pour la découverte de nouvelles thérapies ciblées contre le cancer. En 2003, le criblage de la chimiothèque de l’Institut Curie/CNRS a permis de mettre en évidence une famille de composés actifs sur deux de ces enzymes : CK2 et Pim-1. L’objectif de cette thèse était de synthétiser des analogues des « hits » de la chimiothèque possédant le squelette 5-azaindole afin d’en améliorer les propriétés biologiques. La préparation de tels composés étant peu décrite dans la littérature, trois voies de synthèse flexibles et efficaces ont été développées. L’élaboration de 5-azaindoles diarylés symétriques a tout d’abord été mise au point par hétéroannélation pallado-catalysée à partir de dérivés de la 4-aminopyridine. Les composés monosubstitués en position 2 ont ensuite été obtenus par réaction domino sila-Sonogashira/cyclisation 5-endo. Enfin, un procédé one-pot couplage de Sonogashira/aminopalladation/élimination réductrice a permis d’accéder aux molécules diarylées non symétriques avec une régiosélectivité contrôlée. L’application de ces méthodologies a conduit à la préparation de 70 composés fonctionnalisés dont la cytotoxicité et l’activité inhibitrice sur CK2 ont été évaluées. Une étude structure-activité a été réalisée et les fragments d’intérêt que doit posséder une molécule de type 5-azaindole pour inhiber efficacement la kinase ont ainsi été identifiés. / Protein kinases represent promising targets for anti-cancer drug design. In 2003, inhibitors of two of these enzymes, CK2 and Pim-1, were identified by the screening of the Curie Institute/CNRS small-molecule library. The aim of this thesis was to synthesize derivatives of these hits with a 5-azaindole scaffold in order to optimize their biological activity. As the synthesis of such molecules was not reported in the literature, efficient and flexible procedures were developed to access to these structures. Diarylated symmetrical 5-azaindoles were thus prepared by palladium-catalyzed heteroannulation from 4-aminopyridines derivatives. The methodology was subsequently extended to silylalkynes and led to monoarylated products through domino sila-Sonogashira/5-endo cyclization. Finally, a one-pot Sonogashira coupling/aminopalladation/reductive elimination afforded unsymmetrical compounds with a total control of the regioselectivity. Using these methodologies, 70 functionalized molecules were easily prepared. Their cytotoxicity and biological activity as CK2 inhibitors were then evaluated. A structure-activity relationship study was performed, which led to the identification of two key structural elements for the CK2 inhibitory potency of 5-azaindoles.

Die heterotetramere Proteinkinase CK2 nimmt aufgrund der großen Anzahl und Diversität ihrer Substrate, sowie aufgrund ihrer Eigenschaft Signalwege miteinander zu vernetzen eine Sonderstellung innerhalb der Kinasen ein. CK2 beeinflusst Proliferation, Differenzierung und Apoptose, Prozesse an denen auch Polyamine und der MAPK-Signalweg beteiligt sind. Eine vor kurzem durchgeführte Arbeit beschreibt die Bindung von CK2 an das Gerüstprotein KSR und die Verstärkung des MAPK-Signalwegs durch Phosphorylierung von Raf-Proteinen in Vertebraten. In dieser Arbeit konnte gezeigt werden, dass CK2 auch in Drosophila mit KSR interagiert und das einzige in Drosophila vorhandene Raf-Potein (DRaf) in vitro phosphoryliert. Im Gegensatz zur Phosphorylierung der humanen B-Raf und C-Raf Proteine an Serin 446 bzw. Serin 338 innerhalb der „negative charge regulatory region“ (N-Region), führten Kinasereaktionen und Massenspektrometrische Untersuchungen zur Identifizierung von Serin 11 als CK2 Phosphorylierungsstelle in DRaf, während ein zu Serin 446 in B-Raf äquivalentes Serin in der N-Region in Drosophila nicht durch CK2 phosphoryliert wird. Durch Überexpression von DRaf sowie von zwei DRaf-Varianten bei denen Serin 11 durch Alanin oder Aspartat substituiert wurde (DRafS11A und DRafS11D) konnte in Zellkulturexperimenten gezeigt werden, dass die Ladung an der Aminosäureposition 11 die Funktion von DRaf beeinflusst, wobei eine negative Ladung an dieser Stelle zur Phosphorylierung und Aktivierung der Effektorkinase Erk führt. Die Phosphorylierung durch CK2 ist unabhängig von regulatorischen Botenstoffen ("second messengers"), wird aber durch Bindung von Polyaminen moduliert. Intrazelluläre Polyamine entstammen zum grossen Teil dem zellulären Aminosäurekatabolismus und beeinflussen die Phosphorylierung von DRaf durch CK2 in vitro, wobei Spermin ein effizienter Inhibitor der Reaktion ist, während die Effekte von Putrescin und Spermidin gering sind. Auch in Drosophila Schneider S2 Zellen und in adulten weiblichen Fliegen hat Spermin einen inhibitorischen, CK2-abhängigen Effekt auf die Aktivierung von Erk. Ausserdem konnte gezeigt werden, dass Putrescin und Spermidin in der Lage sind die Aktivierung von Erk, im Vergleich zu Zellen die nur mit Spermin behandelt wurden, zu erhöhen. Das spricht dafür, dass die Phosphorylierung von DRaf und die davon abhängige Aktivierung von Erk durch CK2 von der Menge und Relation der verschiedenen Polyamine zueinander abhängt. Die Ergebnisse dieser Arbeit lassen den Schluss zu, dass der Polyaminmetabolismus über CK2 mit dem MAPK-Signalweg verknüpft ist. Nachdem Polyamine durch Aminosäurekatabolismus enstehen, kann auf diese Weise der MAPK-Signalweg in Abhängigkeit der Verfügbarkeit zellulärer Aminosäuren reguliert werden. Vorversuche zeigten eine Beeinflussung von Proliferation und Apoptose durch CK2 und Polyamine. Weitere Untersuchungen sind aber nötig um spezifische Einflüsse von Polyaminen und CK2 auf zelluläre Prozesse wie Proliferation, Differenzierung und Apoptose aufzudecken. / Because of its high number and diversity of substrates, as well as its ability to cross-link signalling pathways, the heterotetrameric protein kinase CK2 has an exceptional position within kinases. CK2 influences proliferation, differentiation and apoptosis, processes in which also polyamines and the MAPK-signalling pathway are involved. A recent publication delineates binding of CK2 to the scaffold protein KSR and the enhancement of the MAPK-signalling pathway by phosphorylation of Raf-proteins in vertebrates. In my thesis I could show that CK2 also interacts with KSR in Drosophila and phosphorylates the only existing Raf protein in Drosophila (DRaf) in vitro. In contrast to the phosphorylation of human B-Raf- and C-Raf-proteins on serine 446 respectively serine 338 within the "negative charge regulatory region" (N-region), kinase reactions and mass spectrometric analyses led to the identification of serine 11 as phosphorylation site in DRaf, whereas a serine in the N-region, which corresponds to serine 446 of B-Raf, is not phosphorylated by CK2 in Drosophila. In cell culture experiments overexpression of DRaf and two DRaf-variants, in which serine 11 was substituted by alanine or aspartate (DRafS11A and DRafS11D), revealed the charge at amino acid position 11 to affect the function of DRaf, with a negative charge leading to phosphorylation and activation of the effector kinase Erk. Phosphorylation by CK2 is independent of second messengers, whereas it is modified by binding of polyamines. Intracellular polyamines mainly derive from cellular amino acid catabolism and modulate the phosphorylation of DRaf by CK2 in vitro with spermine being an efficient inhibitor of the reaction, whereas the effects of putrescine and spermidine are minor. In Drosophila Schneider S2 cells and adult flies spermine inhibits the activation of Erk in a CK2-dependent way. Furthermore administration of putrescine and spermidine in combination with spermine leads to enhanced Erk activation in cells compared to cells that are treated with spermine. These results suggest that phosphorylation of DRaf and the subsequent activation of Erk by CK2 are dependent on the amount and relative concentrations of polyamines. Altogether the results of this work demonstrate a role for CK2 in linking polyamine metabolism to the MAPK-signalling pathway. Since polyamines derive from amino acid catabolism, the MAPK-signalling pathway can be regulated dependent on the availability of cellular amino acids. Preliminary experiments point to CK2- and polyamine-dependent effects on proliferation and apoptosis. Further investigations are necessary to reveal specific effects of polyamines and CK2 on cellular processes like proliferation, differentiation and apoptosis.

This thesis explores two approaches to fragment-based drug discovery. First, protein target CK2 was chosen due to its importance in the cancer phenotype. A literature fragment, NMR154L, proved to be a promising compound for fragment development, due to its binding at the interface site of the protein rather than the highly conserved ATP pocket. Analogues were synthesised of this fragment leading to a candidate with a better IC50. Additionally, computer modelling of the interface site suggested that a series of spirocyclic compounds would inhibit this protein. These were synthesised and tested in vitro. Results from these tests were analysed and informed the synthesis of new inhibitors with the aid of crystal structures and computer modelling. Secondly, to address the lack of spirocyclic scaffolds in fragment screening libraries a number of diversity-orientated synthetic campaigns were undertaken. The first of these utilised glycine as starting material. Two terminal alkenes were installed. The alkenes were linked and the amino and acidic residues cyclised. This allowed for the formation of a diverse range of spirocyclic scaffolds from this one starting material. Having established chemistry for linking amino and acidic residues a campaign with dehydroalanine was under taken. This would allow for the installation of the second ring by pericyclic chemistry as well as using chemistry previously established. This pericyclic chemistry was also applied to synthesising spirocycles from rings with exocyclic double bonds. These being readily installed from Wittig chemistry, this allowed utilisation of starting materials which contained a cyclic ketone. Of these azetidinone was a good candidate due to the fact it was a commercially available building block and allowed access to spirocycles containing a 4-membered ring; an underrepresented ring size. Finally, computation analysis was carried out on the library to assess it diversity and any potential biological targets which these fragments may inhibit.

Protein kinase CK2 phosphorylates wheat eIF2, eIF3, eIF4B, eIF5 and three 60S ribosomal proteins. The substrate specificity of CK2[alpha] toward various plant initiation factor substrates was altered in vitro through holoenzyme formation in the presence of regulatory [beta]-subunits. This presents a potential mechanism through which the differential expression and sub-cellular distribution of CK2 [beta]-subunits could regulate phosphorylation of various CK2 substrates in plants. Our analysis of initiation factor phosphopeptides produced by in vitro phosphorylation identified 20 CK2 phosphorylation sites in eIF2[alpha], eIF2[beta], eIF3c, eIF4B, and eIF5. Native wheat eIF5 was prepared in the presence of phosphatase inhibitors and analyzed by mass spectrometry. Native wheat eIF5 was determined to be a phosphoprotein containing at least 3 phosphorylation sites. The C-terminal CK2 site (S451) of native eIF5 was completely phosphorylated, and tryptic fragments containing the other in vitro CK2 two sites (S209, T240) also appear to be partially phosphorylated. Many of the CK2 phosphorylation sites identified are in conserved binding domains of the yeast multifactor complex (eIF1/eIF3/eIF5/eIF2/GTP/Met-tRNAi[superscript Met). This observation lead to the hypothesis that CK2 phosphorylation may regulate the formation of plant multifactor complexes. The results presented here suggest that plant initiation factors are capable of forming complexes similar to those previously reported in yeast. The in vitro interaction of initiation factors within these complexes appears to be enhanced by phosphorylation of eIF2, eIF3c, and eIF5 by CK2. Site-directed mutagenesis of eIF5 to remove CK2 phosphorylation sites not only prevents the CK2 mediated increase in interaction with eIF1, but also resulted in reduced stimulation of translation initiation in vitro. / text

Histone deacetylases (HDAC) 1 and 2 play crucial role in chromatin remodeling and gene expression regimes, as part of multiprotein corepressor complexes. Protein kinase CK2-driven phosphorylation of HDAC1 and 2 regulates their catalytic activities and is required to form the corepressor complexes. Phosphorylation-mediated differential distributions of HDAC1 and 2 complexes in regulatory and coding regions of transcribed genes catalyze the dynamic protein acetylation of histones and other proteins, thereby influence gene expression. During mitosis, highly phosphorylated HDAC1 and 2 heterodimers dissociate and displace from mitotic chromosomes. Our goal was to identify the kinase involved in mitotic phosphorylation of HDAC1 and 2. We postulated that CK2-mediated increased phosphorylation of HDAC1 and 2 leads to dissociation of the heterodimers, and, the mitotic chromosomal exclusions of HDAC1 and 2 are largely due to the displacement of HDAC-associated proteins and transcription factors, which recruit HDACs, from chromosomes during mitosis. We further explored the role of un- or monomodified HDAC1 and 2 complexes in immediate-early genes (IEGs), FOSL1 (FOS-like antigen-1) and MCL1 (Myeloid cell leukemia-1), regulation. Dynamic histone acetylation is an important regulator of these genes that are overexpressed in a number of diseases and cancers. We hypothesized that transcription dependent recruitment of HDAC1 and 2 complexes over the gene body regions plays a regulatory role in transcription and splicing regulation of these genes. We present evidence that CK2-catalyzed increased phosphorylation of HDAC1 and 2 regulates the formation of distinct corepressor complexes containing either HDAC1 or HDAC2 homodimers during mitosis, which might target cellular factors. Furthermore, the exclusion of HDAC-recruiting proteins is the major factor for their displacement from mitotic chromosomes. We further demonstrated that un- or monophosphorylated HDAC1 and 2 are associated with gene body of FOSL1 in a transcription dependent manner. However, HDAC inhibitors prevented FOSL1 activation independently of the nucleosome response pathway, which is required for IEG induction. Interestingly, our mass spectrometry results revealed that HDAC1 and 2 interact with a number of splicing proteins, in particular, with serine/arginine-rich splicing factor 1 (SRSF1). HDAC1 and 2 are co-occupied with SRSF1 over gene body regions of FOSL1 and MCL1, regardless of underlying splicing mechanisms. Using siRNA-mediated knockdown approaches and HDAC inhibitors, we demonstrated that alternative splicing of MCL1 is regulated by RNA-directed localized changes in the histone acetylation levels at the alternative exon. The change in histone acetylation levels correlates with the increased transcription elongation and results in change in MCL1 splicing by exon skipping mechanism. Taken together, our results contribute to further understanding of how the multi-faceted HDAC1 and 2 complexes can be regulated and function in various processes, including, but not limited to, transcription regulation and alternative splicing. This can be an exciting area of future research for therapeutic interventions.

Histone deacetylases (HDAC) 1 and 2 play crucial role in chromatin remodeling and gene expression regimes, as part of multiprotein corepressor complexes. Protein kinase CK2-driven phosphorylation of HDAC1 and 2 regulates their catalytic activities and is required to form the corepressor complexes. Phosphorylation-mediated differential distributions of HDAC1 and 2 complexes in regulatory and coding regions of transcribed genes catalyze the dynamic protein acetylation of histones and other proteins, thereby influence gene expression. During mitosis, highly phosphorylated HDAC1 and 2 heterodimers dissociate and displace from mitotic chromosomes. Our goal was to identify the kinase involved in mitotic phosphorylation of HDAC1 and 2. We postulated that CK2-mediated increased phosphorylation of HDAC1 and 2 leads to dissociation of the heterodimers, and, the mitotic chromosomal exclusions of HDAC1 and 2 are largely due to the displacement of HDAC-associated proteins and transcription factors, which recruit HDACs, from chromosomes during mitosis. We further explored the role of un- or monomodified HDAC1 and 2 complexes in immediate-early genes (IEGs), FOSL1 (FOS-like antigen-1) and MCL1 (Myeloid cell leukemia-1), regulation. Dynamic histone acetylation is an important regulator of these genes that are overexpressed in a number of diseases and cancers. We hypothesized that transcription dependent recruitment of HDAC1 and 2 complexes over the gene body regions plays a regulatory role in transcription and splicing regulation of these genes. We present evidence that CK2-catalyzed increased phosphorylation of HDAC1 and 2 regulates the formation of distinct corepressor complexes containing either HDAC1 or HDAC2 homodimers during mitosis, which might target cellular factors. Furthermore, the exclusion of HDAC-recruiting proteins is the major factor for their displacement from mitotic chromosomes. We further demonstrated that un- or monophosphorylated HDAC1 and 2 are associated with gene body of FOSL1 in a transcription dependent manner. However, HDAC inhibitors prevented FOSL1 activation independently of the nucleosome response pathway, which is required for IEG induction. Interestingly, our mass spectrometry results revealed that HDAC1 and 2 interact with a number of splicing proteins, in particular, with serine/arginine-rich splicing factor 1 (SRSF1). HDAC1 and 2 are co-occupied with SRSF1 over gene body regions of FOSL1 and MCL1, regardless of underlying splicing mechanisms. Using siRNA-mediated knockdown approaches and HDAC inhibitors, we demonstrated that alternative splicing of MCL1 is regulated by RNA-directed localized changes in the histone acetylation levels at the alternative exon. The change in histone acetylation levels correlates with the increased transcription elongation and results in change in MCL1 splicing by exon skipping mechanism. Taken together, our results contribute to further understanding of how the multi-faceted HDAC1 and 2 complexes can be regulated and function in various processes, including, but not limited to, transcription regulation and alternative splicing. This can be an exciting area of future research for therapeutic interventions.

Pancreatic cancer is one of the deadliest cancers with a five-year survival rate of 6%. Pancreatic cancer is resistant to conventional chemotherapy and is usually diagnosed at late stages. Current treatment options have minimal effects in extending patients' lives beyond 10 months. One significant limitation in developing treatments to combat pancreatic cancer is its immunosuppressive microenvironment. Pancreatic cancer secretes factors that activate immunosuppressive cells, such as regulatory T cells (Tregs). These Tregs suppress effector CD4+ and CD8+ T cell anti-tumor immune responses. Therefore, novel treatment options to reduce Treg-mediated immune suppression and increase the numbers and functions of CD4+ and CD8+ T cells are paramount to enhance anti-tumor immunity in pancreatic cancer tumor-bearing (TB) hosts. The alternatively spliced transcription factor Ikaros is essential for lymphocyte development and is considered a tumor suppressor in T cells. Ikaros' protein stability and function are regulated by its phosphorylation and dephosphorylation by protein kinase CK2 and phosphatase 1 (PP1), respectively. Mutations and functional inactivation of Ikaros have mainly been investigated in T cell leukemias and lymphomas. In this dissertation, we investigated the role of Ikaros in regulating T cell homeostasis in murine pancreatic cancer. In this study, we report that Ikaros proteins are degraded by the ubiquitin-proteasome pathway in response to factors produced by murine pancreatic cancer cells. Our results further suggest that an increase in CK2 activity leads to Ikaros' degradation and disrupts its localization to pericentromeric heterochromatin in our murine pancreatic TB model. This loss of Ikaros expression is accompanied by an imbalance in T cell homeostasis. More specifically, we observe a significant decrease in effector CD4+ and CD8+ T cells but an increase in Treg percentages in TB and spontaneous pancreatic cancer models. T-cell specific defects in Ikaros protein expression were also observed in TB CD3+ T cells. Apigenin, a natural plant flavonoid and CK2 inhibitor, restored expression of some Ikaros isoforms in our TB model. Apigenin also displayed immunological benefits evident by enhanced anti-tumor immunity in TB mice. These data provide mechanistic and functional evidence that pharmacological inhibition of CK2 can regulate Ikaros expression and identifies the possible involvement of Ikaros in regulating T cell immune responses in murine pancreatic cancer.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19364号 / 医博第4041号 / 新制||医||1011(附属図書館) / 32378 / 新制||医||1011 / 京都大学大学院医学研究科医学専攻 / (主査)教授 上杉 志成, 教授 山下 潤, 教授 野田 亮 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM