Immortalisierung embryonaler Fibroblasten aus Wildtyp und Hupki (Human p53 knock-in) Mäusen durch Veränderungen des p19Arf/p53 Kontrollweges und Erst-Charakterisierung des neuen Prolin 72-kodierenden Hupki-Mausstamms

Aufgrund zunehmenden Wissens um die Regulation des Wachstums maligner Zellen können neue Therapieansätze gefunden werden. Dafür ist es notwendig, mehr über die komplexen Mechanismen der Tumorentstehung und der unbegrenzten Proliferation, der Immortalisierung, von Zellen zu wissen. Immortale Zellen besitzen im Unterschied zu normalen Zellen kein begrenztes Teilungsvermögen, welches abhängig von der Anzahl der Zellteilungen und der Länge der Telomere (Harley et al., 1990) ist. Genauso unterscheiden sich Zelllinien von primären embryonalen (normalen) Zellen. Diese teilen sich bereits nach wenigen Passagen nicht mehr und treten in die Seneszenz ein, die mit charakteristischen morphologischen, zellphysiologischen, molekularen und biochemischen Veränderungen verbunden ist (Kanungo, 1994). Murine und humane Fibroblasten unterscheiden sich in den Mechanismen der Seneszenz: Der Hauptmechanismus der Seneszenz. Die 20%ige Sauerstoff Atmosphäre der Zellkulturbedingungen übt in den primären, embryonalen murinen Fibroblasten (MEFs) einen oxidativen Stress auf die Zellproliferation aus. P19/ARF-p53 scheint der wichtigste Regulationsmechanismus für die Seneszenz in diesen Zellen zu sein. Mit der Inaktivierung von Tumorsuppressorgenen wie z.B. p53 oder pRb durch Punktmutationen oder Deletionen kann die zelluläre Seneszenz unterbrochen und die Zelle zur Immortalisierung gebracht werden. Als Transkriptionsfaktor und Tumorsuppressor weist das p53- Gen Mutationen in 50% aller menschlichen Tumoren auf. Bekannt ist der p53- Polymorphismus im Codon 72 im Exon 4 in der Polyprolindomäne, das entweder für die Aminosäure Arginin (CGC) oder Prolin (CCC) kodiert. Beide Varianten zeigen biochemische Unterschiede im Zellzyklus, der Apoptose und der Tumorgenese-Regulation Gegenstand der vorliegenden Arbeit war die Untersuchung der spontanen Immortalisierungsrate der MEFs und der Hupki Maus Fibroblasten, die einen Teil des humanen Arginin p53- Gens vom Exon 4 zum Exon 9, HUFs R/R genannt, tragen (die HUFs wurden von der Humanen P53 knock in Maus (Hupki Maus) (Luo et al., 2001a) etabliert). Die MEFs weisen eine deutlich höhere Empfindlichkeit gegenüber der 20%igen Sauerstoffatmosphäre der Zellkulturbedingungen als die HUFs R/R auf. Nur ca. 10% (11 von 121) der gesamten primären Zellpopulationen überlebte die Seneszenz und traten in den Immortalisierungsprozess ein. Mehr als 60% der etablierten Zelllinien (7 von 11) weisen entweder p53 missense- Mutationen (5 von 7) vom Typ G>C oder C>G Transversion, mit einer Überexpression an p19 Protein, oder den p19/ARF- DNA Verlust (2 von7) auf. Dagegen verhielten sich die HUFs R/R, die in 90% der primären Zellklone zu immortalisierten Linien auswuchsen (109/120), deutlich resistenter gegenüber den angewandten reaktiven Sauerstoffspezies (reactive oxygene species (ROS)) als die MEFs. Nur 20% der HUFs Zellklone (4 von 20) weisen eine Punkmutation oder eine Deletion in der p53-DNA-Bindungsdomäne auf. 80% der restlichen Zelllinien sind nicht dadurch betroffen Die durchflusszytometrische Analyse der Apoptose mittels Annexin/PI- Kit zeigt, dass die stressigen in vitro Zellkulturbedingungen mehr primäre MEFs in die Apoptose treiben als HUFs R/R. Nachdem die erste Hupki Maus mit dem p53 Arginin Protein ein recht gutes Model für in vivo und in vitro Untersuchungen des humanen p53 Gens darstellt, wurde eine zweite Hupki Maus mit der Prolin- Variante hergestellt, um die multiplen Fragestellungen nach dem p53 Polymorphismus zu beantworten. Die ersten im Rahmen der vorliegenden Arbeit durchgeführten in vitro Studien zeigen in den Hupki Prolin (HUFs PP) Fibroblasten eine hohe Menge an p21 WAF in den klassischen in vitro Zellkulturbedingungen auf, die in den primären, embryonalen Hupki Arginin Fibroblasten. Erst nach Induktion mit gamma-Strahlen erreicht wurde. Dagegen weisen die HUF Zellen mit der p53 Arginin Variante eine Induktion der Perp (P53 apoptosis effactor related to PMP22) nach einer Gamma-Strahlen Exposition auf. Studien zeigten einen Zusammenhang zwischen dem heterozygoten Arg/Pro Genotyp und dem Lungenkarzinom (Fan et al., 2000). Auch das Prolin- Codon Pro/ Pro Genotyp weist eine Assoziierung mit Lungentumoren (Kawajiri et al., 1993) auf. Von 47, mit dem Prokarzinogenen Benzo(a)pyren B(a)P behandelten, primären, embryonalen heterozygoten Hupki Arginin/Prolin (HUFs RP) Zellpopulationen ließen sich 20 (42%) als Zelllinien etablieren: Davon weisen 25% der Zellklone eine p53 G>C, C>G oder C>T Punktmutation auf dem Prolin- Allel auf, gefolgt vom einem Verlust der Heterozygosität (LOH) des Arginin-Allels. Dieses Ergebnis scheint sich von der Immortalisierung der mit B(a)P behandelten Hupki hetereozygoten Arginin Fibroblasten (Liu et al., 2005) deutlich zu unterscheiden

"Beige" Cross Talk Between the Immune System and Metabolism

With thymic senescence the epithelial network shrinks to be replaced by adipose tissue. Transcription factor TBX-1 controls thymus organogenesis, however, the same TBX-1 has also been reported to orchestrate beige adipose tissue development. Given these different roles of TBX-1, we have assessed if thymic TBX-1 expression persists and demonstrates this dualism during adulthood. We have also checked whether thymic adipose involution could yield beige adipose tissue. We have used adult mouse and human thymus tissue from various ages to evaluate the kinetics of TBX-1 expression, as well as mouse (TEP1) and human (1889c) thymic epithelial cells (TECs) for our studies. Electron micrographs show multi-locular lipid deposits typical of beige adipose cells. Histology staining shows the accumulation of neutral lipid deposits. qPCR measurements show persistent and/or elevating levels of beige-specific and beige-indicative markers (TBX-1, EAR-2, UCP-1, PPAR-gamma). We have performed miRNome profiling using qPCR-based QuantStudio platform and amplification-free NanoString platform. We have observed characteristic alterations, including increased miR21 level (promoting adipose tissue development) and decreased miR34a level (bias toward beige adipose tissue differentiation). Finally, using the Seahorse metabolic platform we have recorded a metabolic profile (OCR/ECAR ratio) indicative of beige adipose tissue. In summary, our results support that thymic adipose tissue emerging with senescence is bona fide beige adipose tissue. Our data show how the borders blur between a key immune tissue (the thymus) and a key metabolic tissue (beige adipose tissue) with senescence. Our work contributes to the understanding of cross talk between the immune system and metabolism

Pulmonary cancers across different histotypes share hybrid tuft cell/ionocyte-like molecular features and potentially druggable vulnerabilities

Tuft cells are chemosensory epithelial cells in the respiratory tract and several other organs. Recent studies revealed tuft cell-like gene expression signatures in some pulmonary adenocarcinomas, squamous cell carcinomas (SQCC), small cell carcinomas (SCLC), and large cell neuroendocrine carcinomas (LCNEC). Identification of their similarities could inform shared druggable vulnerabilities. Clinicopathological features of tuft cell-like (tcl) subsets in various lung cancer histotypes were studied in two independent tumor cohorts using immunohistochemistry (n = 674 and 70). Findings were confirmed, and additional characteristics were explored using public datasets (RNA seq and immunohistochemical data) (n = 555). Drug susceptibilities of tuft cell-like SCLC cell lines were also investigated. By immunohistochemistry, 10–20% of SCLC and LCNEC, and approximately 2% of SQCC expressed POU2F3, the master regulator of tuft cells. These tuft cell-like tumors exhibited “lineage ambiguity” as they co-expressed NCAM1, a marker for neuroendocrine differentiation, and KRT5, a marker for squamous differentiation. In addition, tuft cell-like tumors co-expressed BCL2 and KIT, and tuft cell-like SCLC and LCNEC, but not SQCC, also highly expressed MYC. Data from public datasets confirmed these features and revealed that tuft cell-like SCLC and LCNEC co-clustered on hierarchical clustering. Furthermore, only tuft cell-like subsets among pulmonary cancers significantly expressed FOXI1, the master regulator of ionocytes, suggesting their bidirectional but immature differentiation status. Clinically, tuft cell-like SCLC and LCNEC had a similar prognosis. Experimentally, tuft cell-like SCLC cell lines were susceptible to PARP and BCL2 co-inhibition, indicating synergistic effects. Taken together, pulmonary tuft cell-like cancers maintain histotype-related clinicopathologic characteristics despite overlapping unique molecular features. From a therapeutic perspective, identification of tuft cell-like LCNECs might be crucial given their close kinship with tuft cell-like SCLC

Canonical WNT/β-Catenin Signaling Plays a Subordinate Role in Rhabdomyosarcomas

The development of skeletal muscle from immature precursors is partially driven by canonical WNT/β-catenin signaling. Rhabdomyosarcomas (RMS) are immature skeletal muscle-like, highly lethal cancers with a variably pronounced blockade of muscle differentiation. To investigate whether canonical β-catenin signaling in RMS is involved in differentiation and aggressiveness of RMS, we analyzed the effects of WNT3A and of a siRNA-mediated or pharmacologically induced β-catenin knock-down on proliferation, apoptosis and differentiation of embryonal and alveolar RMS cell lines. While the canonical WNT pathway was maintained in all cell lines as shown by WNT3A induced AXIN expression, more distal steps including transcriptional activation of its key target genes were consistently impaired. In addition, activation or inhibition of canonical WNT/β-catenin only moderately affected proliferation, apoptosis or myodifferentiation of the RMS tumor cells and a conditional knockout of β-catenin in RMS of Ptchdel/+ mice did not alter RMS incidence or multiplicity. Together our data indicates a subordinary role of the canonical WNT/β-catenin signaling for RMS proliferation, apoptosis or differentiation and thus aggressiveness of this malignant childhood tumor

WNT4 overexpression and secretion in thymic epithelial tumors drive an autocrine loop in tumor cells in vitro

BackgroundWNT4-driven non-canonical signaling is crucial for homeostasis and age-related involution of the thymus. Abnormal WNT signaling is important in many cancers, but the role of WNT signaling in thymic tumors is largely unknown.Materials & MethodsExpression and function of WNT4 and FZD6 were analyzed using qRT–PCR, Western blot, ELISA, in biopsies of non-neoplastic thymi (NT), thymoma and thymic carcinomas. ShRNA techniques and functional assays were used in primary thymic epithelial cells (pTECs) and TC cell line 1889c. Cells were conventionally (2D) grown and in three-dimensional (3D) spheroids.ResultsIn biopsy, WHO classified B3 thymomas and TCs showed increased WNT4 expression compared with NTs. During short-term 2D culture, WNT4 expression and secretion declined in neoplastic pTECs but not in 3D spheroids or medium supplemented with recombinant WNT4 cultures. Under the latter condition, the growth of pTECs was accompanied by increased expression of non-canonical targets RAC1 and JNK. Down-regulation of WNT4 by shRNA induced cell death in pTECs derived from B3 thymomas and led to decreased RAC1, but not JNK protein phosphorylation. Pharmacological inhibition of NF-κB decreased both RAC1 and JNK phosphorylation in neoplastic pTECs.ConclusionsLack of the age-related decline of non-canonical WNT4 expression in TETs and restoration of declining WNT4 expression through exogeneous WNT4 or 3D culture of pTECs hints at an oncogenic role of WNT4 in TETs and is compatible with the WNT4 autocrine loop model. Crosstalk between WNT4 and NF-κB signaling may present a promising target for combined interventions in TETs

Precious metal carborane polymer nanoparticles: characterisation of micellar formulations and anticancer activity

YesWe report the encapsulation of highly hydrophobic 16-electron organometallic ruthenium and osmium carborane complexes [Ru/Os(p-cymene)(1,2-dicarba-closo-dodecarborane-1,2-dithiolate)] (1 and 2) in Pluronic® triblock copolymer P123 core–shell micelles. The spherical nanoparticles RuMs and OsMs, dispersed in water, were characterized by dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), and synchrotron small-angle X-ray scattering (SAXS; diameter ca. 15 and 19 nm, respectively). Complexes 1 and 2 were highly active towards A2780 human ovarian cancer cells (IC50 0.17 and 2.50 μM, respectively) and the encapsulated complexes, as RuMs and OsMs nanoparticles, were less potent (IC50 6.69 μM and 117.5 μM, respectively), but more selective towards cancer cells compared to normal cells.We thank the Leverhulme Trust (Early Career Fellowship no. ECF-2013-414 to NPEB), the University of Warwick (Grant no. RDF 2013-14 to NPEB), the Swiss National Science Foundation (Grant no. PA00P2_145308 to NPEB and PBNEP2_142949 to APB), the ERC (Grant no. 247450 to PJS), EPSRC (EP/G004897/ 1 to APB, and EP/F034210/1 to PJS), Institute of Advanced Study (IAS) – University of Warwick (Fellowship to JJSB), and Science City (AWM/ERDF) for support. We thank the Wellcome Trust (055663/Z/98/Z) for funding to the Electron Microscopy Facility, School of Life Sciences, University of Warwick

Nanomatériaux dendritiques vers l'électronique moléculaire et la médecine

Des dendrimères à cœur aromatique ayant des propriétés originales en électronique moléculaire ont été synthétisés pour des applications en tant que batteries moléculaires avec des systèmes redox robustes et pour la thérapie anti-cancer par capture de neutrons. Le premier thème a été focalisé sur les dendrimères à terminaison métallocénique ou bimétallocénique avec la recherche des propriétés électroniques y compris la stabilisation de valence mixte avec application pour la synthèse de nanoparticules métalliques contrôlée par le potentiel redox. Le second thème a impliqué la synthèse de dendrimères ayant des terminaisons carborane en collaboration avec le groupe du Prof. N. Hosmane de Chicago. Pour les deux thèmes, les assemblages ont été réalisés par réaction “click“ de type Huisguen entre des azotures terminaux des dendrimères et les alcynes terminaux. Les dendrimères ont été caractérisés à la fois à l'aide de techniques spectroscopiques et analytiques traditionnelles et à l'aide de techniques propres aux macromolécules (chromatographie d'exclusion stérique, RMN DOESY, diffusion de lumière dynamique). Le concept de base commun aux deux thèmes consiste à utiliser la topologie dendritique de grands dendrimères pour concentrer dans un nano-espace minimum une quantité élevée d'électrons pour les batteries moléculaires ou d'atomes de bore dont la densité est essentielle pour l'efficacité de la thérapie anti-cancer par capture de neutrons.Dendrimers with aromatic core with original properties in molecular electronics have been synthesized for applications as molecular batteries with robust redox systems and the anti-cancer therapy by neutron capture. The first theme was focused on metallocene-terminated or bimetallocenyl dendrimers with the research of electronic properties including the stabilization of mixed valence with application for the synthesis of metal nanoparticles controlled by the redox potential. The second theme concerned the synthesis of dendrimers with carborane termini in collaboration with the Chicago group of Prof. N. Hosman. For both subjects, the connections have been made by "click" reaction of type Huisguen between alkynes and dendrimer terminals azides. The dendrimers were characterized at a time using traditional analytical and spectroscopic techniques and using own techniques to macromolecules (size exclusion chromatography, DOESY NMR, dynamic light scattering). The basic concept common to both themes is the use of dendritic topology of large dendrimers to concentrate in a nano-space at least a high amount of electrons to molecular batteries or boron atoms whose density is essential for efficiency of the anti-cancer therapy by neutron capture

Etude hydrogeologique et simulation par modeles mathematiques de la nappe de Khemis-Miliana (bassin du Haut Chelif, Algerie)

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Nanomatériaux dendritiques vers l'électronique moléculaire et la médecine

Des dendrimères à cœur aromatique ayant des propriétés originales en électronique moléculaire ont été synthétisés pour des applications en tant que batteries moléculaires avec des systèmes redox robustes et pour la thérapie anti-cancer par capture de neutrons. Le premier thème a été focalisé sur les dendrimères à terminaison métallocénique ou bimétallocénique avec la recherche des propriétés électroniques y compris la stabilisation de valence mixte avec application pour la synthèse de nanoparticules métalliques contrôlée par le potentiel redox. Le second thème a impliqué la synthèse de dendrimères ayant des terminaisons carborane en collaboration avec le groupe du Prof. N. Hosmane de Chicago. Pour les deux thèmes, les assemblages ont été réalisés par réaction “click“ de type Huisguen entre des azotures terminaux des dendrimères et les alcynes terminaux. Les dendrimères ont été caractérisés à la fois à l'aide de techniques spectroscopiques et analytiques traditionnelles et à l'aide de techniques propres aux macromolécules (chromatographie d'exclusion stérique, RMN DOESY, diffusion de lumière dynamique). Le concept de base commun aux deux thèmes consiste à utiliser la topologie dendritique de grands dendrimères pour concentrer dans un nano-espace minimum une quantité élevée d'électrons pour les batteries moléculaires ou d'atomes de bore dont la densité est essentielle pour l'efficacité de la thérapie anti-cancer par capture de neutrons.Dendrimers with aromatic core with original properties in molecular electronics have been synthesized for applications as molecular batteries with robust redox systems and the anti-cancer therapy by neutron capture. The first theme was focused on metallocene-terminated or bimetallocenyl dendrimers with the research of electronic properties including the stabilization of mixed valence with application for the synthesis of metal nanoparticles controlled by the redox potential. The second theme concerned the synthesis of dendrimers with carborane termini in collaboration with the Chicago group of Prof. N. Hosman. For both subjects, the connections have been made by "click" reaction of type Huisguen between alkynes and dendrimer terminals azides. The dendrimers were characterized at a time using traditional analytical and spectroscopic techniques and using own techniques to macromolecules (size exclusion chromatography, DOESY NMR, dynamic light scattering). The basic concept common to both themes is the use of dendritic topology of large dendrimers to concentrate in a nano-space at least a high amount of electrons to molecular batteries or boron atoms whose density is essential for efficiency of the anti-cancer therapy by neutron capture