Hepatocellular carcinoma (HCC) is the most common and devastating malignant tumor in Taiwan. The major factors involved in the molecular pathogenesis for the development of HCC have been explored in recent years. An extensive array of growth factors and their receptors have been identified and may act as positive and negative modulators in different stages of hepatocarcinogenesis. HDGF (hepatoma-derived growth factor) is a novel growth factor, identified from conditioned medium of hepatoma cell line. HDGF has growth stimulating activity for fibroblast and some hepatoma cells. The high homology of protein sequence to HMG (high mobility group) protein but with distinct structure indicate it is a novel growth factor with mitogenic effect. Recently, elevated HDGF expression was found in developing kidneys but little in adult kidney. Besides, HDGF expression was found to be correlated with angiogenic status of tissues. Thus, it is speculated that HDGF plays a role during embryonic development and angiogenesis. Besides, HDGF also plays a role in cell-to-cell interaction and cell movement. HDGF is a growth factor that is involved in stimulating vascular smooth muscle cells (SMCs) proliferation during development and in disease. HDGF contains a true bipartite nuclear localization sequence necessary for nuclear targeting. It is required for HDGF stimulation of DNA replication and cell proliferation in vascular smooth muscle cell. In present studies, have transfected HDGF cDNA to 3T3 cell and the HDGF expression was verified by Western blot analysis. HDGF expression altered the morphologies and growth rate of 3T3 cells by 2-fold. Besides, HDGF-expressing cells were more resistant to serum-starvation. Injection of 3T3-HDGF cells, but not 3T3 cells, resulted in tumor formation in nude mice, suggesting that the angiogenic and mitogenic functions of HDGF might contribute to carcinogenesis. By using various reagents including H2O2, dexamethasome, taxol, cisplatin, CoCl2 and KCN, the cellular stress studies revealed differential responses between in 3T3 and 3T3-HDGFH. analyzed dose and time-dependent effects of UV irradiation and found that 3T3-HDGF cells are more sensitive to UV irradiation than 3T3 cells and susceptible to apoptosis. hope these experiments will bring further insights into the cellular function of HDGF, particularly during angiogenic process, thereby enable to evaluate its role during HCC progression and its potential as clinical marker and therapeutic target for HCC.

Cutaneous malignant melanoma is the fastest increasing malignancy in humans. Hepatoma-derived growth factor (HDGF) is a novel growth factor identified from human hepatoma cell line. HDGF overexpression is correlated with poor prognosis in various types of cancer including melanoma. However, the underlying mechanism of HDGF overexpression during melanoma carcinogenesis remains unclear. In this study, adding exogenous HDGF stimulated the invasion and colonies formation of B16-F10 melanoma cells. Adenovirus vectors encoding HDGF and HDGF-RNAi were generated and characterized to up- and down-regulated HDGF expression in B16-F10 melanoma cells. It was found that HDGF overexpression stimulated the proliferation, invasiveness, anchorage-independent growth of B16-F10 melanoma cells whereas HDGF knockdown exerted opposite effects. In lung-metastasis model, intravenous injection of HDGF-overexpressing melanoma cells resulted in increased metastasis while HDGF-downregulated melanoma cells caused decreased metastasis. Similarly, in primary melanoma model, subcutaneous injection of HDGF-overexpressing melanoma cells enhanced while HDGF-downregulated melanoma cells reduced the tumor burden in mice. Histological analysis revealed increased tumor proliferation and neovascularization with concomitant reduction of apoptosis in HDGF-overexpressing melanoma. Moreover, HDGF-overexpressing melanoma also exhibited enhanced propensity to metastasize from the primary tumors to lymph node and lung. Finally, it was found that HDGF overexpression increased nuclear factor kappa B (NF£eB) activities and Akt phosphorylation up and down stream alternation like PI3K, PTEN, I£eB and it¡¦s subunit IKK£\, IKK£], IKK£^ in melanoma cells. It also found that HDGF overexpression influenced MITF and HIF1£\ in melanoma after gene delivery. HDGF also altered EMT changes like E,N-cadherin, vimentin, and £],£^-catenin. The present study provides conclusive evidence that HDGF upregulation promotes the growth and metastasis of melanoma by promoting the survival and vascularization. Besides, HDGF knockdown may constitute a novel strategy for melanoma control.

Untersuchung der Butyrateffekte auf die Genexpression von Zellkulturen während der Adenom-Karzinom-Sequenz mit Hilfe von Microarrays. Analyse des HDGF-Genclusters. Verwendete Zellkulturen Geki2, HT29 und SW620 / Examination of butyrate effects on genexpression of cellculteres during adenom-carcinom-sequence by use of microarrays. Analysis of hdgf-gencluster. USed cellcultures Geki2, HT29 und SW620.

Im Rahmen dieser Arbeit wurde die Expression des putativen Onkogens HDGF (Hepatoma Derived Growth Factor) in der humanen Kolonkarzinomzelllinie HT29 mittels RNA Interferenz herunterreguliert. Zwei unterschiedliche, für das Zielgen HDGF spezifische siRNAs wurden hierzu jeweils in einen Plasmidvektor kloniert. Zellen der Kolonkarzinomzelllinie HT29 wurden zunächst transient und stabil mit den beiden resultierenden Plasmidvektoren transfiziert, die Expression von HDGF in den transfizierten Zellen mittels Realtime-PCR quantifiziert und mit der Expression in mit Lipofektamin behandelten Kontrollzellen verglichen. Durch die stabile Transfektion beider Plasmidvektoren konnte die HDGF-Expression fast komplett supprimiert werden. Im Rahmen eines cDNA-Array konnten außer einer Expressionsverminderung von HDGF noch multiple Expressionsveränderungen anderer Gene identifiziert werden. Dies ist zum einen durch unspezifische, durch den Plasmidvektor bedingte Effekte erklärbar. Zum anderen aber ist die Deregulation vieler dieser Gene ein Effekt der Inaktivierung von HDGF. / In this thesis the expression of the putative oncogene HDGF (Hepatoma Derived Growth Factor) in a colorectal cancer cell-line was down-regulated by means of RNA interference. The expression of HDGF was almost completely suppressed. The expression of various other genes was also influenced. This is on the one hand due to unspecific effects caused by the plasmidvector. On the other hand it is also an effect of the gene silencing of HDGF.

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. An extensive array of growth factors and their receptors have been identified and may act as positive and negative modulators in different stages of liver carcinogenesis. Hepatoma-derived growth factor (HDGF) is a novel growth factor identified from conditioned medium of Huh-7 hepatoma cell line. HDGF has growth stimulating activity for various types of cells. Recent evidence indicates that HDGF upregulation is associated with poor survival outcome and tumor progression in HCC, non-small cell lung carcinoma and melanoma. However, the exact function and molecular mechanism of HDGF overexpression during HCC progression remain largely unknown. In the first project (Chapter 2) of this thesis study, we started with characterizing in HDGF release and response to exogenous HDGF between benign HepG2 and malignant SK-Hep-1 hepatoma cells. It was found that serum deprivation significantly stimulated the HDGF secretion in SK-Hep-1 cells but not HepG2 cells. Interestingly, SK-Hep-1 cells did not increase the secretion of vascular endothelial growth factor (VEGF), a potent angiogenic factor, during serum deprivation. Besides, SK-Hep-1 cells were more responsive to the growth- and migration-promoting effect of exogenous HDGF. We also validated the angiogenic functions of recombinant HDGF protein in vitro and in vivo. In the second project (Chapter 3), we investigated the influence of cellular HDGF level on the neoplastic potential of hepatoma cells. Adenovirus vectors encoding HDGF, Ad-HDGF, and antisense HDGF, Ad-HDGF (-), were generated to modulate the cellular HDGF levels in SK-Hep-1 cells. Adenovirus-mediated HDGF gene delivery increased the HDGF expression and release, and stimulated the proliferation, migration and anchorage-independent growth of SK-Hep-1 cells. In contrast, infection with Ad-HDGF (-) reduced the HDGF expression and secretion, and attenuated the oncogenic behaviors of SK-Hep-1 cells. Implanting HDGF-overexpressing SK-Hep-1 cells led to the accelerated growth of xenografted hepatoma in SCID mice while implantation of HDGF-downregulated SK-Hep-1 cells caused retarded tumor growth. Histological analysis revealed the increased proliferation and neovascularization in HDGF-overexpressing tumors. This could be attributed to elevated VEGF expression and activation of the nuclear factor kappa B (NF£eB) activities by HDGF upregulation in SK-Hep-1 cells. In the third project (Chapter 4), we delineated the mechanism underlying HDGF-induced VEGF secretion and activation of NFB pathway in SK-Hep-1 cells. Adding recombinant HDGF protein enhanced the VEGF release by SK-Hep-1 cells particularly during serum starvation. This was associated with a concomitant increment in VEGF protein and mRNA levels in SK-Hep-1 cells. Like many mitogens, HDGF increased the production of reactive oxygen species (ROS) including superoxide anion and hydrogen peroxide in a dose-dependent manner. Pretreatment with antioxidants abolished the HDGF-induced VEGF secretion. NF£eB is a pivotal transcription factor for regulation of pro-inflammatory cytokines and genes such as VEGF and cycloxygenase¡V2 (COX-2). Application of HDGF stimulated NF£eB-driven luciferase activities. This was correlated with a dose- and time-depedent increment of NF£eB (p65) by HDGF. HDGF treatment also elevated the COX-2 protein levels and activities in SK-Hep-1 cells. In addition, blockade of COX-2 by NS-398 attenuated the HDGF-induced VEGF secretion, suggesting the involvement of COX-2. Finally, it was found that HDGF stimulated the phosphorylation of Akt, Erk1/2, and p38 MAPK. Inhibition of Akt by LY294002 also diminished the HDGF-induced VEGF secretion. These studies suggest that HDGF induces oxidative stress to activate NF£eB/COX-2/Akt pathway, thereby stimulating VEGF expression and release. In summary, this thesis study brings functional and mechanistic insights on how aberrant HDGF expression contributes to angiogenesis and tumorigenesis during liver carcinogenesis.

In this study, we investigated the mechanisms of HDGF on cell migration in non-transformed NIH/3T3 cells. HDGF promoted the migration and the formation of dorsal ruffles and podosome rosettes. Besides, HDGF supply increased the PI3K expression, Akt phosphorylation and PTEN phosphorylation as well as stimulated the RhoA, Rac1, and Cdc42 activities. Furthermore, Adenoviral gene transfer of PTEN attenuated migration and PI3K/Akt/Rho GTPases signaling in HDGF-overexpressing transfectants. Pharmaceutical intervention using the PI3K inhibitor, LY294002, potently reversed HDGF-stimulated cell migration, dorsal ruffles formation and podosome formation as well as the RhoA, Rac1, and Cdc42 activities. Thus, HDGF elicits the activation of PI3K/Akt /Rho GTPases signaling cascade and promotes cytoskeleton remodeling to stimulate cellular migration. Moreover, we investigate the expression profile of HDGF during breast carcinogenesis. Immunohistochemical studies revealed elevated HDGF expression in human breast cancer. Nuclear HDGF labelling index was positively correlated with tumour grade, stage and proliferation index, but negatively correlated with survival rate in breast cancer patients. Our data also showed that HDGF over-expression was associated with lymph node metastasis and represented an independent prognostic factor for tumor recurrence. Furthermore, Immunoblot study revealed that elevated HDGF expression significantly higher in breast cancer cells (MDA-MB-231 cells) than that in non-transformed breast cells (MCF-7 cells). Consistently, higher invasive potency and colony formation also observed in MDA-MB-231 cells than in MCF-7 cells. Adenovirus-mediated HDGF over-expression and exogenous HDGF treatment stimulated the invasiveness and colony formation as well as E-cadherin down-regulation and Vimentin up-regulation. Conversely, either HDGF knockdown by RNA interference, HDGF antibody neutralization or BITC-induced EMT suppression in MDA-MB-231 cells attenuated the malignant behavior and elicited EMT reversal by enhancing E-cadherin expression while depleting Vimentin expression. In summary, HDGF elicits the activation of PI3K/Akt/Rho GTPases signaling cascade, thereby promoting cytoskeleton remodeling to stimulate cellular migration. Moreover, the formation of podosome rosettes is correlated with cell invasion, the podosome-stimulating capability of HDGF is consistent with HDGF regulates the metastasis of breast cancer through modulating of epithelial-mesenchymal transition. Therefore, our results provide not only novel insights into the role of the HDGF in cell migration and tumor metastasis, but also validate a novel prognostic indicator for breast cancer. Key words: Hepatoma-derived growth factor, PI3K, Akt, epithelal-mesenchemal transition, E-cadherin, Vimentin

Liver fibrosis, a major medical problem with significant morbidity and mortality, is considered as a wound-healing response to a variety of chronic stimuli. It is characterized by an excessive deposition of extracellular matrix (ECM) proteins, which disrupts the normal architecture of liver and ultimately leads to pathophysiological damage to liver. Hepatoma-derived growth factor (HDGF), a growth factor originally purified from hepatoma cells, is highly expressed in fetal hepatocytes and hepatoma. It is known to play multifunctional roles in mitogenesis, organogenesis, embryogenesis, and tumorigenesis. Its expression correlates with the proliferating state of hepatocellular carcinoma (HCC) and serves as a prognostic factor. Since liver fibrosis frequently occurs prior to HCC development, the specific aim of this study is to investigate the role of HDGF in the progression of liver fibrosis by using animal models of mice receiving either bile duct ligation surgery or carbon tetrachloride administration. Quantitative real-time PCR and Western blotting analysis showed a significant elevation of HDGF expression in both models. HDGF levels correlated with progression of liver fibrosis in a time-dependent manner as well as paralleled with the expression of other two fibrotic markers, transforming growth factor-b1 (TGF-b1) and pro-collagen type I, in fibrotic livers. Intriguingly, the over-expressed HDGF protein was localized mainly in perivenous hepatocytes of fibrotic livers. Besides, adenovirus-mediated HDGF gene delivery potentiated the production of TGF-b1 and pro-collagen type I, thereby enhancing the intrahepatic collagen matrix deposits as evidenced by Sirius red stain and morphometrical analysis. In cultured hepatocytes, TGF-b1 and HDGF mutually up-regulated their de novo synthesis only when grown on collagen-coated matrix, strongly suggesting that the TGF-b1- and/or HDGF-driven pro-fibrogenic signaling is collagen-dependent and a vicious circle may exist at the initial stage of hepatic fibrogenesis. Moreover, administration with recombinant HDGF stimulated BrdU uptake and synthesis of both a-smooth muscle actin and pro-collagen type I in cultured hepatic stellate cells, implicating that a mode of paracrinal action lies between these two cell types. In conclusion, HDGF plays a pro-fibrogenic role during liver fibrosis and blockade of HDGF pathway may potentially constitute the preventive or therapeutic strategies for chronic liver diseases.

Das Ziel dieser Arbeit war die Darstellung der Einflüsse verschiedener Interleukine auf die HDGF-Expression in verschiedenen Kolonzelllinien. HDGF stellt einen Wachstumsfaktor dar, der nicht nur physiologisch bei der Entwicklung einiger Gewebe wie der Niere, der Leber und des Darms von Be-deutung ist, sondern auch eine wichtige Rolle in der Karzinogenese verschie-dener Tumoren spielt. Hierzu zählen unter anderem das hepatozelluläre Karzi-nom, das NSCLC und das Melanom. Von besonderer Relevanz ist seine Rolle in der Pathogenese des kolorektalen Karzinoms. Die verwendeten Interleukine (1beta, 4, 5, 8 und 13) zeigen sowohl inhibierende als auch fördernde Eigenschaften in Bezug auf die Karzinogenese von kolorektalen Tumoren. Dies steht im Einklang mit früheren Resultaten der Literatur. Die vier verschiedenen Zelllinien, eine Adenomzelllinie, zwei Adenokarzinomzelllinien sowie eine Zelllinie aus Lymphknotenmetastasenzellen wurden mit den verschiedenen Interleukinen inkubiert und mittels REAL TIME-RT-PCR analysiert. Die Ergebnisdarstellung in Blockdiagrammen zeigt semiquantitativ die relative HDGF-Expression. So lassen sich Aussagen über Anstieg oder Abfall der Expression durch den Einfluss der verschiedenen Interleukine machen. Die hier gezeigten Ergebnisse lassen, wie auch schon teilweise in der Literatur beschrieben, für alle Interleukine außer für IL 1beta, sowohl hemmende als auch tumorunterstützende Effekte beobachten. Interleukin 1beta zeigt in Kongruenz der vorbeschriebenen Studien, im Gegensatz zu den anderen Zytokinen, in allen Zelllinien tumorfördernde Eigenschaften. Für IL 4 ist zunächst in den Adenomzellen ein antitumoröser Effekt zu erkennen, dieser kehrt sich in der Metastasenzelllinie in eine förderndene Wirkung um. In den Adenokarzinomzelllinien sind weder eindeutige suppressive noch unterstützende Wirkungen zu verzeichnen. Über einen Zusammenhang zwischen dem Grad der malignen Transformation und unterschiedlichem Ansprechen auf IL 4 lässt sich jedoch bisher nur spekulieren. Für IL 5 ist ein ähnliches Verhalten zu beobachten. Eine anfängliche inhibitorische Wirkung auf die HDGF-Expression in den Adenomzellen sowie Adenokarzinomzellen kehrt sich in der Metastasenzelllinie in den gegenteiligen Effekt um. Auch hier lässt sich eine Umkehr der ausgelösten Effekte mit fortschreitender maligner Transformation vermuten. IL 8 zeigt kongruente Effekte zu IL 4 und IL 5, jedoch lassen sich für IL 8 in der Literatur bisher nur tumorunterstützende Wirkungen finden. Hier lässt sich in den Adenomzellen eine suppressive Wirkung verzeichnen, wohingegen in den beiden Adenokarzinomzelllinien fördernde Effekte beobachtet werden. In der Metastasenzelllinie lassen sich jedoch weder positive noch negative Auswirkungen feststellen. Des Weiteren spiegeln auch die Ergebnisse des Einflusses von IL 13 die Vielgestaltigkeit der Wirkweisen dieses Interleukins dar, mit tumorhemmenden Effekten in den Adenom- sowie Metastasenzellen und fördernder Wirkung in den HT29-Zellen. Über die genauen Mechanismen, inwiefern ein Interleukin die Expression von HDGF hochreguliert oder supprimiert, kann zum momentanen Zeitpunkt nur spekuliert werden. Es kann jedoch vermutet werden, dass ein gewisser Zu-sammenhang zwischen dem Grad der malignen Transformation und der Wirk-weise der Interleukine existiert. Entscheidend sind hier sicherlich klonal erwor-bene Alterationen einzelner Signalkaskaden. Festzuhalten ist zum einen, dass bis auf IL 1beta für alle Zytokine der Einfluss auf HDGF vom jeweiligen Zellsystem abhängt. Diese Ergebnisse machen eine Schlüsselrolle von HDGF eher unwahrscheinlich, vielmehr scheint seine Regulation hier in teilweise komplexe Regulationsmechanismen mit eingebunden zu sein. Dass diese Alterationen möglicherweise auch im Rahmen der Karzinogenese bzw. der Akquise der Metastasierungsfähigkeit entstehen könnten, zeigen die teilweise bestehenden Unterschiede zwischen der verwendeten Adenomzelllinie und den Karzinomzelllinien respektive zwischen Karzinom- und Metastasenzelllinie. Die beschriebenen Ergebnisse geben einen Anhaltspunkt, in welche Richtung die einzelnen Interleukine wirken, zumindest in wie weit hier ein Einfluß auf die Transkription von HDGF als Surrogatmarker der Mitogenese erfolgt. Um die Komplexität und Vielfalt der Effekte von Interleukinen in Bezug zu Tumorstadium, Invasivität sowie Metastasierungsfähigkeit in Einklang zu bringen, bedarf es jedoch weiterführender Studien. Es lies sich zeigen, dass die angewendeten Interleukine generell Einfluss auf die Expressionshöhe von HDGF in verschiedenen Kolonzelllinien haben und als exogene Faktoren in die Regulation eingreifen können. Dies könnte ein weiterer Ansatz zur Etablierung immunmodulatorischer Therapieoptionen in soliden Neoplasien in der Zukunft sein. / Hepatoma-derived growth factor (HDGF) is a growth factor which plays a role in physiological development of some organ tissues and in the carcinogensis of a few tumors like colorectal cancer, hepatocellular cancer, NSCLC. For this study especially the role of HDGF with regard to colorectal cancer is important. The main focus is set on the influences that different interleukins have on the expression of HDGF in different gut-tissues and colon cancer-tissues. To this end, five interleukins (1beta, 4, 5, 8 and 13) with different effects on the carcinogenesis of colorectal cancer (inhibition/promotion) were investigated. It is known from the literature that all five interleukins show different behavior. Four cell lines–one adenoma cell line, two different cell lines of adenoma carcinoma of intestine, one cell line of lymph node metastase of adenoma carcinoma of intestine–were incubated with the five interleukins and analyzed with Real Time-RT-PCR. This method allows for an observation of changes of the relative HDGF-expression. The results show that all interleukins have an influence on the HDGF-expression. The most pronounced effects are observed in dependency of the concentration of the interleukins under investigation. Interleukin 1beta exhibits throughout a tumor supporting behavior. In contrast to this, all other interleukins showed that their influence depends on the probed cell line. This suggests that there is a connection between the effect of the interleukin and the degree of malign differentiation. This complex interplay manifests itself, for instance, in a totally inversion of the effects, with depression of the HDGF-expression in the cell line of adenoma and a promotion in the cell line of metastasis in some experimental runs. These findings are partly concurrent with known properties described in the literature related to colorectal cancer. ln summary the results show that interleukins as exogenous factor can influence the HDGF-expression. However, the data do not allow to derive final statements on the mechanism of regulation. It is imaginable that an alteration of the signal pathways, presumably acquired clonal, determine whether an interleukin shows effects of inhibition or promotion on the cell lines. Therefore, further studies are required to clarify in how far interleukins influence the HDGF-expression.