L’objectif de ce travail était d’évaluer, selon une approche épidémiologique et thérapeutique transversale multimodale, les facteurs pronostiques de survie du CHC dans le cadre de sa prise en charge chirurgicale après transplantation hépatique ou résection chirurgicale. La première étape a été de déterminer les données de survie de la littérature après ces deux traitements chirurgicaux. Nous avons donc réalisé une méta-analyse des données de la littérature afin de comparer les résultats de la survie globale et de la survie sans récidive chez les patients transplantés ou réséqués pour CHC. La deuxième étape a consisté à étudier le score AFP, outil utilisé pour la sélection des patients en vue d’une transplantation hépatique, et de son intérêt pronostique sur la survie dans une cohorte de patients traités par une résection chirurgicale pour CHC. Enfin, la troisième étape a été d’étudier l’impact des inégalités socio-économiques, au moyen de l’index de défavorisation développé par notre équipe, sur la survie des patients transplantés pour carcinome hépatocellulaire.La méta-analyse a montré que le bénéfice de la transplantation hépatique pour carcinome hépatocellulaire en termes de survie globale pour les patients dans les critères de Milan, n’avait pas de bénéfice avant 10 ans après la chirurgie contrairement à la survie sans récidive où il existait une différence significative dès 3 ans après la chirurgie.La deuxième étude a cherché à déterminer si le score AFP, outil de sélection des patients pour transplantation hépatique pour CHC était lui aussi un bon outil de sélection pour les patients à opérer d’une chirurgie. Nous avons pu montrer que ce score était prédictif de récidive après résection hépatique et que si les patients étaient dans le score, cette récidive pouvait bénéficier d’un traitement curateur. / The objective of this work was to assess in an epidemiological and a surgical ways prognosis factors of HCC after liver transplantation or liver resection. First step was to determine in a methodological review the overall and disease free survival results of these two techniques. Second step was to use the AFP-score, selection tool for patients with HCC who need liver transplantation in France, as selection tool for a group of patients who underwent surgical resection for transplantable HCC. Final step was to study influence of social deprivation on survival of patients who underwent liver transplantation for HCC in a Nation-wide study.The meta-analysis showed that Liver Transplantation, in patients with HCC meeting the Milan criteria had no benefits before 10 years for OS, compared to Liver resection. For DFS, the benefit is obtain after 3 years.AFP-score is a useful tool for the patient’s management who are suffering from solitary HCC developed on CLD. In patients “in AFP-score”, up-front LR is not associated with a loss of chance, when compare to up-front LT, based on theoretical 5-years OS.European Deprivation Index does not impact mortality after LT for HCC. Number of HCC and time on waiting-list are independent prognostic factors of survival after liver transplantation for HCC.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23369号 / 医博第4738号 / 新制||医||1051(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 松田 道行, 教授 小川 誠司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Introduction : Le récepteur TLR3 (Toll-like receptor 3) détecte l'ARN double brin viral ou cellulaire; il est exprimé dans les hépatocytes humains dans lesquels son activation engendre une réponse proinflammatoire médiée par la production d’interféron de type I. Dans les cellules cancéreuses, TLR3 peut entraîner l’apoptose par sa capacité à activer la voie extrinsèque des caspases. Notre objectif était de caractériser l’expression et la fonctionnalité de TLR3 dans les carcinomes hépatocellulaires (CHC). Matériels et Méthodes : Ce travail a été mené de manière translationnelle. In vitro : le rôle de TLR3 a été analysé dans un modèle de transformation d’hépatocytes primaires humains (PHH) par les oncogènes SV40LT-ST et H-RasG12 V. In vivo : l’impact de TLR3 a été étudié dans un modèle de souris exprimant l’oncogène SV40 avec un TLR3 sauvage (TLR3+/+) ou invalidé (TLR3-/-). Enfin une cohorte française de 126 patients opérés d’un CHC de toutes étiologies a été analysée afin d’évaluer la valeur pronostique en termes de récidive du niveau d’expression du récepteur en ARNm (q-rt-PCR) en protéine (Western Blot) dans le foie tumoral par rapport au foie non tumoral. Résultats: In vitro, la transformation cancéreuse de PHH in vitro par SV40LT-ST et H RasG12 V s’accompagne d’une baisse drastique du niveau d’expression de TLR3 en ARNm et en protéine. L'expression forcée de TLR3 avant transduction par SV40LT-ST est responsable de l'entrée en apoptose des cellules. In vivo, dans le modèle murin SV40, les foyers de transformation cancéreuse et de CHC sont significativement plus nombreux dans les souris SV40-TLR3-/- que dans les souris SV40-TLR3+/+ à 8, 10 et 12 semaines. De plus, dans les souris SV40-TLR3-/-, l’évaluation de l’apoptose montre une diminution significative au sein du parenchyme hépatique comparée aux souris SV40-TLR3+/+ sans impact sur la prolifération hépatique ni le recrutement des cellules immunitaires. Enfin dans une série de 126 patients résequés d'un CHC, la sous-expression de l’ARNm de TLR3 (déterminée par rapport à un panel de foies sains) était significativement associée à la récidive précoce post-résection en analyse univariée (HR=1.79 [1.04 - 3.06] p=0.03) et multivariée (HR=1.73 [1.01–2.97] p=0.04). L'impact pronostique de la sous-expression de TLR3 a été validé dans une large cohorte de 306 CHC réséqués issus du TCGA. Conclusion: la sous-expression de TLR3 est un mécanisme d’échappement à la mort cellulaire des hépatocytes par apoptose durant l'hépatocarcinogenèse. L’évaluation du niveau d’expression pourrait servir de biomarqueur puisque l’absence de TLR3 est associée au risque de récidive. A contrario, la présence de TLR3 constitue une cible thérapeutique / Introduction: The receptor TLR3 (Toll-like receptor 3) detects viral or cellular double-stranded RNA; it is expressed in human hepatocytes in which its activation generates a pro-inflammatory response mediated by the production of type I interferon. In cancer cells, TLR3 can cause apoptosis by its ability to activate the extrinsic pathway of caspases. Our goal was to characterize the expression and functionality of TLR3 in hepatocellular carcinoma (HCC). Materials and Methods: This work was conducted in a translational way. In vitro: the role of TLR3 was in a model of transformation of primary human hepatocytes (PHH) by the oncogene SV40LT-ST and H-RasG12V. In vivo: the impact of TLR3 was studied in a mouse model expressing the SV40 oncogene with wild-type TLR3 (TLR3 + / +) or invalidated (TLR3 - / - ). Finally, a French cohort of 126 patients operated on with a CHC of all etiologies was analyzed in order to evaluate the prognostic value in terms of recurrence of the receptor expression at mRNA (q-rt-PCR), protein (Western Blot) levels in the tumoral compared to the non-tumoral liver. Results: In vitro, PHH trasformation by SV40LT-ST and H-RasG12V is asociated with a drastic decrease of TLR3 expression at mRNA and protein levels. A forced expression of TLR3 before SV40LT-ST transduction is responsible for the apoptosis of the cells. In vivo, in the SV40 mouse model, CHC foci were significantly higher in SV40-TLR3- / - mice than in SV40-TLR3+ / + mice at 8, 10 and 12 weeks. In addition, in SV40-TLR3- / - mice, comparison of apoptosis showed a significant decrease in hepatic parenchyma compared to SV40-TLR3+ / + mice with no impact on hepatic proliferation or immune cell infiltration. Finally, in a cohort of 126 patients with resected HCC, the downregulation of TLR3 mRNA (compared to a panel of normal livers) was significantly associated with early post-resection recurrence in univariate analysis (HR = 1.79 [1.04 - 3.06] p = 0.03) and multivariate (HR = 1.73 [1.01-2.97] p = 0.04). The prognostic impact of TLR3 downrégulation was validated in a large cohort of 306 resected CHCs from the Cancer genome Atlas (TCGA). Conclusion: TLR3 downregulation is an escape mechanism to apoptosis during hepatocarcinogenesis. TLR3 expression could be used as a prognosis biomarker since the absence of TLR3 is associated with recurrence. On the other hand, the presence of TLR3 constitutes a therapeutic target

Für Lebertransplantationen bei Patienten mit hepatozellulärem Karzinom stellt sich angesichts der defizitären Organspendesituation die berechtigte Frage, unter welchen Bedingungen diese Form der Therapie ein gutes Outcome für die Patienten verspricht und somit keine Verschwendung der ohnehin knappen Ressourcen darstellt. Ziel dieser Arbeit war es, ein Kollektiv aus 98 Patienten, die an einem hepatozellulären Karzinom erkrankten und im Zeitraum von 1994 bis einschließlich 2010 am Universitätsklinikum Leipzig eine Lebertransplantation erhielten, retrospektiv zu charakterisieren und den Einfluss mehrerer Faktoren auf das Outcome der Patienten zu untersuchen. Bei den Faktoren handelte es sich um die Wartezeit, den präoperativen Einsatz der TACE, den präoperativen AFP-Serumspiegel, sowie die Tumorzahl und -größe. Der Nachbeobachtungszeitraum lag bei 3 Jahren. Die Charakterisierung des Kollektivs erbrachte folgende Ergebnisse: Das Kollektiv bestand zu rund 80% aus Männern. Das mediane Alter zum Zeitpunkt der Transplantation lag bei 59 Jahren. Die Transplantationszahlen bei HCC-Patienten sind am UKL seit Einführung des MELD-Scores 2006 deutlich angestiegen. Die mediane Wartezeit hat sich seit Einführung des MELD-Scores nicht wesentlich verändert. Sie betrug 7,3 Monate in der Prä-MELD-Ära und 6,9 Monate in der MELD-Ära. Mit über 60% war der Alkoholabusus die häufigste Ursache für die Entstehung des hepatozellulären Karzinoms. An zweiter Stelle stand die Hepatitis-C-Infektion. In der Diagnostik des HCC spielte die Computertomographie die größte Rolle. Die Sensitivität des AFP zur Erfassung des HCC (>400 ng/ml) war mit Werten unter 30% sehr niedrig. Die TACE war die mit Abstand am häufigsten durchgeführte, neoadjuvante Maßnahme. Zum Zeitpunkt der Transplantation befanden sich rund 75% der Patienten in einem Stadium bis maximal T2. Das Auftreten von solitären und multifokalen HCCs war in etwa gleich häufig (46,9% vs. 53,1%). Die Milan-Kriterien waren bei knapp 39% der Patienten im postoperativen Explantat-Befund überschritten. Nach Transplantation traten bei 26 Patienten Abstoßungsreaktionen auf. 8 Patienten mussten aufgrund eines Transplantatversagens retransplantiert werden. Das postoperative Überleben (intention-to-treat) betrug 75,5% (6 Monate), 71,4% (1 Jahr) und 63,3% (3 Jahre). Die entsprechenden Rezidivraten lagen bei 11,2%, 14,3% und 22,4%. Rezidiven traten am häufigsten in der Spenderleber auf, gefolgt von einem Befall der Lymphknoten und Knochen. Ein signifikanter Einfluss auf das Outcome der Patienten konnte für das AFP, die Tumorzahl und die Milan-Kriterien nachgewiesen werden: Präoperative AFP-Spiegel unter 100 ng/ml zeigten eine signifikant niedrigere Rezidivrate. Multifokale Tumoren waren mit einem signifikant schlechteren 3-Jahres-Überleben verknüpft. Bei Erfüllung der Milan-Kriterien (im postoperativen Explantat-Befund) war die Rezidivrate signifikant und die Überlebensrate deutlich besser. Für die Wartezeit konnte seit Einführung des MELD-Scores eine positive Entwicklung festgestellt werden. Das 3-Jahresüberleben hat sich bei Wartezeiten unter 12 Monaten um 22,5% verbessert. Die Rezidivrate ist bei Wartezeiten über 12 Monate um 15,3% gesunken. Für den Einfluss der TACE auf das Outcome der Patienten konnten keine signifikanten Unterschiede festgestellt werden. Auch andere Studien belegten bisher lediglich einen Vorteil für das erfolgreiche Downstaging gegenüber Patienten, bei denen die TACE erfolglos blieb. Für die Untersuchung des tatsächlichen Nutzens einer TACE vor Transplantation werden daher Studien mit höherem Evidenzgrad benötigt.:Bibliographische Beschreibung 1 Abkürzungsverzeichnis 2 1 Einleitung 3 1.1 Hepatozelluläres Karzinom 3 1.1.1 Epidemiologie 3 1.1.2 Ätiologie 3 1.1.3 Symptome 4 1.1.4 Diagnostik 4 1.1.5 Stadieneinteilung 8 1.1.6 Staging und Therapieoptionen 10 1.2 Lebertransplantation 15 1.2.1 Indikationen 15 1.2.2 Prinzip 15 1.2.3 Nachsorge 16 1.2.4 Begriffsklärungen 17 2 Fragestellung 21 3 Patienten und Methoden 22 3.1 Patienten 22 3.2 Methoden 22 3.2.1 Datenerhebung 22 3.2.2 Statistische Auswertung 23 4 Ergebnisse 25 4.1 Charakterisierung des Kollektivs 25 4.1.1 Allgemeines 25 4.1.2 Vor der Transplantation 26 4.1.3 Histopathologischer Befund 34 4.1.4 Nach der Transplantation 39 4.2 Einflussfaktoren auf das Outcome nach LTX 44 4.2.1 Wartezeit (nach Allokationssystem) 44 4.2.2 Transarterielle Chemoembolisation 48 4.2.3 Alpha-Fetoprotein 50 4.2.4 Tumorzahl und -größe 54 5 Diskussion 58 5.1 Charakterisierung des Kollektivs 58 5.1.1 Allgemeines 58 5.1.2 Vor der Transplantation 59 5.1.3 Histopathologischer Befund 60 5.1.4 Nach der Transplantation 62 5.2 Einflussfaktoren auf das Outcome nach LTX 63 5.2.1 Wartezeit (nach Allokationssystem) 63 5.2.2 Transarterielle Chemoembolisation (TACE) 66 5.2.3 Alpha-Fetoprotein 69 5.2.4 Tumorzahl und -größe 72 6 Zusammenfassung 76 Abbildungsverzeichnis 78 Tabellenverzeichnis 79 Literaturverzeichnis 81 Danksagung 91 Erklärung zur Datenaufbewahrung 92 Erklärung über die eigenständige Abfassung der Arbeit 93

The sex-dependent pituitary growth hormone (GH) secretory profiles, pulsatile in males and persistent in females, regulate sex-biased expression of hundreds of genes in mammalian liver, contributing to sex differences in hepatic metabolism and disease. The sex-biased GH actions in the liver are mediated by STAT5b and enhanced by a network of transcription factors including the male-biased BCL6 and the female-specific CUX2, acting in the context of sex-biased chromatin states. First, the transcriptional and epigenomic changes induced by continuous-GH infusion (cGH) in male mice, which rapidly feminizes the temporal profile of liver STAT5 activity, were examined. RNA-seq analysis determined that cGH repressed the majority of male-biased genes and induced most female-biased genes within 4-days; however, several highly female-specific genes showed partial feminization. Female-biased genes already in an active chromatin state in male liver were induced early; genes in an inactive chromatin state often responded late. Early cGH-responsive genes included Cux2 and Bcl6 and their targets. DNase-seq and ChIP-seq were used to identify changes in sex-specific chromatin accessibility and histone modifications accompanying these cGH-induced gene expression changes. H3-K27me3 is a key sex-biased repressive mark found preferentially at highly female-biased genes in male mouse liver. Consistently, induction of female-biased genes by cGH was associated with loss of H3-K27me3 at their gene bodies. H3K27 methylation is catalyzed by Polycomb Repressive Complex-2 (PRC2) through its homologous catalytic subunits EZH1 and EZH2. An Ezh1-knockout mouse model with a hepatocyte-specific knockout of Ezh2 (DKO) was used to further investigate the role of H3-K27me3 in repressing sex-biased genes in mouse liver. Loss of Ezh1/Ezh2 led to a significant decrease in sex-specific gene expression, with many female-biased genes induced and male-biased genes repressed. These gene responses were more extensive in male than female liver, as was the loss of H3K27me3 sites and the reciprocal increases in active histone marks. There was substantial up-regulation of liver cancer and liver fibrosis-related genes in male and female DKO-mouse liver, with a subset of genes preferentially up-regulated in females. Thus, GH regulated sex-biased liver physiology is dictated by transcription factors arranged in a hierarchical network and by dynamic sex-biased epigenetic states. / 2020-06-12T00:00:00Z

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and chronic hepatitis B virus (HBV) infection is the major risk factor of HCC. The virus encodes HBV X (HBx) protein that plays a critical role in the development of HCC. Studies have revealed numerous HBx-altered genes and signalling pathways that heavily contribute to tumourigenesis of non-tumour hepatocytes. However, the role of HBx in regulating other critical gene regulators such as microRNAs is poorly understood, which impedes the exploration of a complete HBx-associated carcinogenic network. Besides, critical microRNAs that drive the transformation of non-tumour hepatocytes are yet to be identified. Here, we overexpressed C-terminal truncated HBx protein in a non-tumour hepatocyte cell line MIHA, and measured a panel of cancer-associated miRNAs. We observed that oncogenic miR-21 was upregulated upon ectopic expression of this viral protein variant. HBx-miR-21 pathway was prevalent in HCC cells as inhibition of HBx in Hep3B and PLC/PRF/5 cells significantly suppressed miR-21 expression. Subsequently, we showed that the upregulation of miR-21 was mediated by HBx-induced interleukin-6 pathway followed by activation of STAT3 transcriptional factor. The high dependency of miR-21 expression to HBx protein suggested a unique viral oncogenic pathway that could aberrantly affect a network of gene expression. Importantly, miR-21 was essential in the HBx-induced transformation of non-tumour hepatocytes. Inhibition of miR-21 effectively attenuated anchorage-independent colony formation and subcutaneous tumour growth of MIHA cells. Our study suggested that overexpression of miR-21 was critical to promote early carcinogenesis of hepatocytes upon HBV infection.

Most cancers rely disproportionately on glycolysis for energy even in the presence of adequate oxygen supply, a condition known as "aerobic glycolysis", or the Warburg effect. Pharmacological reversal of the Warburg effect has been shown to cause selective apoptosis of tumor cells, presumably by stimulating mitochondrial respiratory chain activity and production of reactive oxygen species that, in turn, induce a caspase-mediated series of reactions leading to cell death. We reasoned that a similar effect on tumor cells might result from up-regulation of the E1α subunit gene (pda1) of the pyruvate dehydrogenase complex (PDC) that catalyzes the rate-limiting step in aerobic glucose oxidation and thus plays a major role in the control of oxidative phosphorylation. To test this postulate, we employed a self-complementary adeno-associated virus (scAAV)-based delivery and expression system for targeting pda1 to the mitochondria of primary cultures of human hepatoblastoma (HB) and hepatocellular carcinoma (HCC) cells. Serotypes 1-10 scAAV vectors that included enhanced green fluorescent (egfp) reporter gene driven by either cytomegalovirus (CMV) or chicken beta-actin (CBA) promoters were analyzed for transduction ability of HB (Huh-6) and HCC (Huh-7 and HepG2) cell lines and primary cultures of normal human hepatocytes. Serotype 3 scAAV-egfp (scAAV3-egfp) vector was the most efficient and transduced up to 90% of cells. We limited the transgene expression primarily to liver cancer cells by generating scAAV3 vectors that contained the human alpha-fetoprotein promoter (AFP)-driven reporter gene (scAAV3.AFP-egfp) and the potentially therapeutic gene scAAV3.AFP-pda1. Infection of Huh-6 cells by the scAAV3.AFP-pda1 vector increased protein expression of E1α, PDC catalytic activity, and late-stage apoptotic cell death. Apoptosis was also associated with increased protein expression of Bcl-X/S, an early marker of apoptosis, and release of cytochrome c into the cytosol of infected HB cells. These data indicate that molecular targeting of mitochondrial oxidative metabolism in liver cancer cells by AAV3-mediated delivery of pda1 holds promise as a novel and effective therapeutic approach for human hepatic tumors.

DNA methylation and histone modifications have emerged as key mechanisms in transcriptional regulation. The target of methylation-induced silencing 1 (TMS1) is a bipartite protein. Recent studies have indicated that methylation-associated silencing of TMS1 occurs in many cancers. However, whether and how TMS1 is regulated by epigenetic mechanisms in cancers remains unknown. In this study we showed that methylation of the TMS1 promoter occurred in five of six hepatocellular carcinoma (HCC) cell lines. TMS1 expression was reduced in four HCC cell lines and correlated with methylation status. Furthermore, the TMS1 promoter was completely methylated and mRNA expression was undetectable. TMS1 expression could be restored by 5-aza-2′-deoxycitidine (5-Aza-dC) (a DNA methyltransferase inhibitor) or trichostatin A (TSA) (a histone deacetylase inhibitor) alone and the promoter methylation. was partially reversible. TSA was more efficient than 5-Aza-dC in inducing TMS1 expression, and the combination of 5-Aza-dC and TSA resulted in markedly synergistic reactivation of the gene and completely reversed promoter methylation. Interestingly, TMS1 promoter methylation-associated gene silencing was accompanied by histone H3 Lysine 9 (H3K9) hypoacetylation and trimethylation. 5-Aza-dC and/or TSA also had some effect on conversion of methylated to acetylated H3K9 in restoring TMS1. This conversion was dynamic at the TMS1 promoter and a decrease in H3K9 trimethylation preceded an increase in H3K9 acetylation after 5-Aza-dC and/or TSA treatment. Our results thus suggest that epigenetic inactivation of TMS1 expression is regulated by promoter hypermethylation and H3K9 modifications in a coordinated way.

Partial hepatectomy (PH) is a treatment of choice for patients suffering from early stage hepatocellular carcinoma (HCC). Ablation of large proportion of the liver is rendered possible because of the ability of the liver to regenerate. Yet, a significant number of patients will experience recursion of the disease. Such relapses are unfortunately rather frequent and constitute a bad prognosis. The development of new strategies aiming at reducing the risk of recursion of HCC is thus a paramount element of the surgery-based treatment. Some previous studies have proposed that the regenerative process as well as the fate of the immune cells during the liver regeneration process is linked to this recurrence phenomenon.In this study, we investigated the impact of PH on HCC development in a pre-clinical murine model. We implanted Hepa1-6 hepatocarcinoma cells (a murine hepatocarcinoma cell line) directly in the liver of mice and compared a non-resected group with a group undergoing 40% PH one week following tumor implantation. Analysis were relying on bioluminescence imaging and flow cytometry. We demonstrated that liver regeneration increases tumoral proliferation. This proliferation was associated with a reduction in the number of liver resident macrophages, i.e. Kupffer cells (KC). KC anti-tumoral activity was also proved using conditional ablation model. We further studied the mechanisms leading to this disappearance and demonstrated that, under normal regeneration conditions, PH-induced KC number reduction was dependent on tumor necrosis factor-α (TNF-α), receptor interacting protein kinase (RIPK) 3 and caspase-8 activation whereas interleukin (IL)-6 acted as a KC pro- survival signal. In mice with previous Hepa 1-6 encounter, the KC reduction changed toward a TNF-α-RIPK3-caspase-1 activation. This data suggest a switch from apoptosis to pyroptosis induction in KC following PH. Moreover, KC disappearance associated with caspase-1 activity induced the recruitment of monocyte derived cells that are beneficial for tumor growth while caspase-8 dependent reduction did not, underlying the importance of macrophages activated death-pathway in regulating the anti-tumoral immune response. Our results show the necessity for comprehensive multidisciplinary treatment approach following PH and propose new targets in order to reduce the relapse of the disease occurring after surgery. / Doctorat en Sciences biomédicales et pharmaceutiques (Médecine) / info:eu-repo/semantics/nonPublished