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• W1840802607 abstract "Research Article17 December 2010Open Access Deregulation of FoxM1b leads to tumour metastasis Hyun Jung Park Hyun Jung Park Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Both authors contributed equally to this work. Search for more papers by this author Galina Gusarova Galina Gusarova Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Both authors contributed equally to this work. Search for more papers by this author Zebin Wang Zebin Wang Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Janai R. Carr Janai R. Carr Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Jing Li Jing Li Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Ki-Hyun Kim Ki-Hyun Kim Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Jin Qiu Jin Qiu Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Search for more papers by this author Yoon-Dong Park Yoon-Dong Park Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Search for more papers by this author Peter R. Williamson Peter R. Williamson Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Section of Infectious Diseases, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Nissim Hay Nissim Hay Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Angela L. Tyner Angela L. Tyner Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Lester F. Lau Lester F. Lau Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Robert H. Costa Robert H. Costa Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Pradip Raychaudhuri Corresponding Author Pradip Raychaudhuri [email protected] Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Jesse Brown VA Medical Center, Chicago, IL, USA Search for more papers by this author Hyun Jung Park Hyun Jung Park Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Both authors contributed equally to this work. Search for more papers by this author Galina Gusarova Galina Gusarova Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Both authors contributed equally to this work. Search for more papers by this author Zebin Wang Zebin Wang Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Janai R. Carr Janai R. Carr Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Jing Li Jing Li Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Ki-Hyun Kim Ki-Hyun Kim Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Jin Qiu Jin Qiu Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Search for more papers by this author Yoon-Dong Park Yoon-Dong Park Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Search for more papers by this author Peter R. Williamson Peter R. Williamson Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA Section of Infectious Diseases, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Nissim Hay Nissim Hay Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Angela L. Tyner Angela L. Tyner Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Lester F. Lau Lester F. Lau Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Robert H. Costa Robert H. Costa Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Search for more papers by this author Pradip Raychaudhuri Corresponding Author Pradip Raychaudhuri [email protected] Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA Jesse Brown VA Medical Center, Chicago, IL, USA Search for more papers by this author Author Information Hyun Jung Park1, Galina Gusarova1, Zebin Wang1, Janai R. Carr1, Jing Li1, Ki-Hyun Kim1, Jin Qiu2, Yoon-Dong Park2, Peter R. Williamson2,3, Nissim Hay1, Angela L. Tyner1, Lester F. Lau1, Robert H. Costa1 and Pradip Raychaudhuri *,1,4 1Department of Biochemistry and Molecular Genetics, UIC-Cancer Center, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA 2Section of Translational Mycology, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA 3Section of Infectious Diseases, University of Illinois at Chicago, Chicago, IL, USA 4Jesse Brown VA Medical Center, Chicago, IL, USA *Tel: +1 312 413 0255, Fax: +1 312 355 3847 EMBO Mol Med (2011)3:21-34https://doi.org/10.1002/emmm.201000107 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions Figures & Info Abstract The forkhead box M1b (FoxM1b) transcription factor is over-expressed in human cancers, and its expression often correlates with poor prognosis. Previously, using conditional knockout strains, we showed that FoxM1b is essential for hepatocellular carcinoma (HCC) development. However, over-expression of FoxM1b had only marginal effects on HCC progression. Here we investigated the effect of FoxM1b expression in the absence of its inhibitor Arf. We show that transgenic expression of FoxM1b in an Arf-null background drives hepatic fibrosis and metastasis of HCC. We identify novel mechanisms of FoxM1b that are involved in epithelial–mesenchymal transition, cell motility, invasion and a pre-metastatic niche formation. FoxM1b activates the Akt-Snail1 pathway and stimulates expression of Stathmin, lysyl oxidase, lysyl oxidase like-2 and several other genes involved in metastasis. Furthermore, we show that an Arf-derived peptide, which inhibits FoxM1b, impedes metastasis of the FoxM1b-expressing HCC cells. The observations indicate that FoxM1b is a potent activator of tumour metastasis and that the Arf-mediated inhibition of FoxM1b is a critical mechanism for suppression of tumour metastasis. The paper explained PROBLEM: Metastasis of tumour cells is the major cause of cancer-related deaths worldwide. However, the molecular mechanisms and pathways that encourage tumour cells to leave the primary site of tumour development and undergo metastasis are poorly understood. A greater understanding of the mechanisms involved in tumour cell metastasis will allow us to identify the molecular targets and then design effective therapy against metastatic tumours. RESULTS: Using liver cancer as a model, we identify that a combination of over-expression of the transcription factor FoxM1 and a loss of the tumour suppressor Arf causes primary liver cancer cells to undergo metastasis to the lung. We show that the metastatic transformation of the liver cancer cells is associated with EMT-like (epithelial to mesenchymal-like) changes. Moreover, expression of FoxM1 in Arf-deficient background induces pre-metastatic niche formation at the site of metastasis (lung). Also, we show that a treatment with an Arf-derived peptide-inhibitor of FoxM1 blocks metastasis of the tumour cells. IMPACT: Over-expression of FoxM1 and loss of Arf expression are common features in many aggressive cancers. Our observations suggest that those changes in cancer cells are related their metastatic activity. Moreover, our observations provide proof-of-principle that inhibition of FoxM1 using an Arf-derived peptide could have strong therapeutic implications. INTRODUCTION Metastasis is the leading cause of cancer-related death. Understanding the molecular mechanisms of metastasis and genetic changes required for metastasis are essential to develop novel therapeutic strategies and improve their efficacy for treatment of the metastatic disease. During tumour progression, cancer cells undergo dramatic changes in cytoskeletal organization to adopt invasive phenotype and eventually metastasize to other organs. Epithelial–mesenchymal transition (EMT), which is associated with reduced cell-surface expression of E-cadherin and altered expression of several cytoskeletal proteins, plays a significant role towards the migratory activity of the tumour cells (Kalluri & Weinberg, 2009). A recent study indicated that the microtubule (MT) destabilizing protein Stathmin/Oncoprotein 18 plays a pivotal role in cell migration/invasion. MT stability controls migration of cells through extracellular matrix, and destabilization of MT by Stathmin increases motility (Baldassarre et al, 2005). Stathmin is often over-expressed in cancer and associated with increased metastasis (Singer et al, 2007). However, the mechanism by which Stathmin is over-expressed in cancer remains elusive. Changes in cancerous cells alone are not sufficient to promote metastasis (Kopfstein & Christofori, 2006). Tumour microenvironment also plays a pivotal role in tumour progression and metastasis (Joyce & Pollard, 2009). The importance of a pre-metastatic niche or local microenvironment at metastatic sites has emerged (Psaila & Lyden, 2009). Increased expression of lysyl oxidase (LOX) has been implicated in tumour cell invasiveness and tumour metastasis (Akiri et al, 2003; Erler et al, 2006; Sakai et al, 2009). LOX is a copper dependent amine oxidase that causes covalent crosslinking of collagen by catalysing oxidative deamination of lysine and hydroxylysine residues in collagen, leading to both inter- and intramolecular crosslinking (Payne et al, 2007). Secreted LOX induces collagen crosslinking at pre-metastatic organs to generate sites that attract Cd11b+ myeloid cells to form a receptive niche for arriving tumour cells (Erler et al, 2009). Forkhead box M1 (FoxM1) is a proliferation-specific transcription factor and plays a critical role in cell cycle progression (Laoukili et al, 2007; Wierstra & Alves, 2007). Gene expression profiling in a number of carcinomas revealed that elevated FoxM1 expression is a general phenomenon and likely to be a crucial step of disease progression in all carcinomas examined (Pilarsky et al, 2004). Moreover, over-expression of FoxM1 strongly correlates with disease progression and poor prognosis in various human malignancies (Calvisi et al, 2009; Chandran et al, 2007; Dai et al, 2007; Gialmanidis et al, 2009; Liu et al, 2006; Yang et al, 2009). The role of FoxM1 in tumour progression has been studied extensively in mice using liver carcinogenesis models. Alb-Cre-mediated deletion of FoxM1 in the livers of FoxM1 fl/fl strain rendered the mice resistant to development of hepatocellular carcinomas (HCCs) induced by the diethylnitrosamine/phenobarbital (DEN/PB) liver carcinogenesis protocol (Kalinichenko et al, 2004). Also, deletion of FoxM1 in pre-existing HCC inhibited tumour growth, indicating a persistent requirement for FoxM1 in tumour progression (Gusarova et al, 2007). Although the increased expression of FoxM1 correlates with tumour grade and metastasis in various human malignancies (Chandran et al, 2007; Dai et al, 2007), its contribution to the metastasis process remains undefined. Interestingly, there is growing evidence that the tumour suppressor p19Arf (p14Arf in human) can inhibit cell invasion and tumour metastasis (Aguirre et al, 2003; Chen et al, 2008). Deletion of p19Arf in p53-null background further facilitated malignant tumour conversion and metastasis, indicating p53-independent tumour suppressor functions of p19Arf (Kelly-Spratt et al, 2004). In fact, mounting evidence suggests that p19Arf (p14Arf in human) confers its tumour suppression activity through p53-dependent and -independent pathways (Eischen et al, 1999; Kamijo et al, 1999; Lin & Lowe, 2001; Schmitt et al, 1999). Previously, we reported that p19Arf targets FoxM1b, a splice variant of FoxM1, to the nucleolus and inhibits the transcriptional activity of FoxM1b (Kalinichenko et al, 2004). An 18 amino acid sequence between residues 26 and 44 of p19Arf is sufficient to bind and inhibit its activity. Intraperitoneal injection of a peptide corresponding to the 26–44 residues of p19Arf inhibited the proliferation of the HCC cells and stimulated their apoptosis (Gusarova et al, 2007). In this study, using a liver carcinogenesis model, we show that transgenic (Tg) expression of FoxM1b combined with the loss of its inhibitor p19Arf induces liver fibrosis and metastasis, which resemble the pathology of human HCC. In addition, we show that an Arf-derived peptide that inhibits FoxM1b inhibits metastasis of HCC cells. This work reveals novel mechanisms of FoxM1b in tumour metastasis and provides evidence that inhibition of FoxM1b will be significant in therapy for metastatic tumours. RESULTS Transgenic expression of FoxM1b in an Arf-deficient background drives aggressive HCC, hepatic fibrosis and pulmonary metastasis of liver cancer Elevated expression of FoxM1 has been reported in human HCC and its expression is indispensable for the development and progression of HCC (Calvisi et al, 2009; Gusarova et al, 2007; Kalinichenko et al, 2004; Okabe et al, 2001). However, over-expression of FoxM1 alone in a Tg mouse model had only marginal effects on liver cancer development and progression (Kalinina et al, 2003). Since the tumour suppressor p19Arf inhibits FoxM1 transcriptional activity (Kalinichenko et al, 2004), we considered the possibility that p19Arf might be a dominant inhibitor of FoxM1 in tumour development and progression. Therefore, we sought to determine the effects of FoxM1 over-expression in the absence of p19Arf. We bred p19Arf-null mice with FoxM1b Tg mice, which ubiquitously express FoxM1b driven by Rosa26 promoter. The bi-transgenic heterozygotes (Arf+/−Rosa26-FoxM1b Tg) were backcrossed for six to nine generations into the C57BL/6 background. Fourteen-day old pups from the Arf+/−Rosa26-FoxM1b Tg crosses were subjected to the DEN/PB tumour induction protocol, a well-established method that effectively generates HCC with greater than 90% penetrance. As expected, the majority of the mice developed HCC (Fig 1A and C). FoxM1b Tg;Arf−/− mice exhibited markedly increased mortality and tumour burden (Fig S1A and B of Supporting Information). Moreover, FoxM1b Tg;Arf−/− mouse livers appeared fibrotic (Fig 1A). Robust collagen deposition along with strong alpha-smooth muscle actin (α-SMA) expression was observed in a significant number (5 out of 12) of FoxM1b Tg;Arf−/− mice (Fig 1B). No collagen deposition or α-SMA staining was detected in the parenchyma of Arf−/− or FoxM1b Tg mice (Fig 1B). Figure 1. FoxM1b Tg;Arf−/− mice developed fibrosis and metastases of HCC. A.. We sacrificed the mice and harvested liver tissues after 33 weeks of DEN/PB exposure. FoxM1b Tg;Arf−/− liver tumours (a–c) and lung lesions (d) are shown. B.. Liver sections were stained for the activated HSC marker α-SMA or Masson's trichrome for collagen deposition. Magnification: ×200. Lower panel: Liver extracts were subjected to Western blotting assay using α-SMA antibody. C.. Numbers of mice bearing lung lesions and liver tumours are shown. For all panels of (B) and (D), the scale bar (indicated in the upper left panel) = 200 µm. D.. Lung lesions were stained with hematoxylin and eosin (H&E). Magnification: ×100. E.. Total RNA from the lung was extracted for RT-PCR using primers specific for albumin. 1. liver; 2. lung; 3–4. Arf−/− (A: lung); 5–13. FoxM1b Tg;Arf−/− (FA−/−: lung); 14. FoxM1b Tg;Arf−/− (FA−/−: spleen); 15–18. FoxM1b Tg;Arf+/− (FA+/−: lung). Download figure Download PowerPoint Interestingly, we found that approximately 75% (14/18) of the FoxM1b Tg;Arf−/− mice developed lesions in the lung, as shown in Fig 1A (part d) and C. We also found that one of the FoxM1b Tg;Arf−/− mice displayed nodules in the spleen. A significantly lower percentage (less than 30%) of the FoxM1b Tg;Arf+/− mice and 13% (4/27) of the Arf−/− mice exhibited nodules in the lung. Histologically, the lung nodules from Arf−/− mice resembled lung adenocarcinomas (Fig 1D). Since the Arf−/− mice are known to develop lung adenocarcinomas (Kamijo et al, 1999) and, in the DEN/PB model, lung metastasis is relatively rare, we determined the origin of the lung nodules. We assayed for albumin mRNA expression, which is only synthesized in the liver. A significant number (7 out of 9) of the lung tumour samples (and one tumour sample from spleen) from the FoxM1b Tg;Arf−/− mice expressed albumin mRNA (Fig 1E), confirming the presence of HCC-derived cells in the lung. Also, the lung lesions from FoxM1b Tg;Arf+/− mice were positive for albumin-mRNA, while the lung samples from the Arf−/− mice were negative for albumin mRNA (Fig 1E). Therefore, it is likely that the albumin-negative lung nodules observed in Arf−/− mice were indeed lung adenocarcinomas (Kamijo et al, 1999). Fewer metastases in Arf+/− background (less than 30% compared to 75% in Arf−/− background) provide strong evidence that Arf inhibits metastasis driven by FoxM1b expression. HCC cells derived from the FoxM1b Tg;Arf−/− mice are highly tumourigenic and metastatic To determine whether FoxM1b in the Arf−/− background could support metastasis in a cell-autonomous fashion, we studied the HCC cells derived from the FoxM1b Tg;Arf−/− mice and compared them with the HCC cells from the Arf−/− mice, as there was no evidence of metastasis in Arf+/+ or FoxM1b Tg; Arf+/+ mice. Also, it was difficult to obtain stable lines in the Arf +/+ background. We isolated HCC cells from the livers of three independent mice of each genotype. As expected, all three FoxM1b Tg;Arf−/− HCC lines expressed higher levels of FoxM1 than Arf−/− HCC cells (Fig S2A of Supporting Information). Also, no expression of p19Arf was observed in the isolated HCC cells (Fig S2A of Supporting Information). We then examined anchorage-independent growth ability of HCC cells. FoxM1b Tg;Arf−/− cells formed significantly more and larger colonies compared to the Arf−/− cells in soft agar (Fig 2A). The increased tumourigenicity was further confirmed by xenograft experiments. Arf−/− or FoxM1b Tg;Arf−/− HCC cells were subcutaneously injected into the flank of athymic nude mice. The Arf−/− HCC cells failed to develop tumours in 3 weeks after injection, whereas the FoxM1b Tg;Arf−/− cells started to grow exponentially with a short latency period and all mice injected developed palpable tumours (Fig 2B). Figure 2. Cells from FoxM1b Tg;Arf−/− HCC are highly tumourigenic and metastatic. A.. Soft agar assays were performed to compare anchorage-independent growth ability. Bar graph presents quantification of the representative data of three independent experiments. Data are expressed as mean ± SD (*p < 0.05). B.. 5 × 105 cells were subcutaneously injected into nude mice. The tumour diameter was measured at the indicated time points. Data are expressed as mean ± SD. C–E.. 106 RFP labelled cells were injected into 8-week-old male nude mice intravenously via tail vein. (C) Mice were subjected to fluorescence imaging. (D and E) Mice were then sacrificed and lung tissues were harvested. Lungs were weighed (D) and fixed with Bouin's solution for 24 h. Macroscopic surface tumour nodules were counted (E). Data are expressed as mean ± SD (*p < 0.05). Download figure Download PowerPoint To determine the metastatic potential of the HCC cells, cells stably expressing the Red fluorescence protein (RFP) were injected into nude mice via tail vein. The mice were imaged using a fluorescence imager after injection of the cells. As shown in Fig 2C, the mice injected with FoxM1b Tg;Arf−/− cells displayed stronger fluorescence signals in lungs compared to the mice injected with tumour cells isolated from Arf−/− HCCs. To obtain a more quantitative measure of the tumour burden, we removed lungs, weighed to compare tumour burden between two groups, and fixed the lungs in Bouin's solution to count macroscopic surface metastases. Clearly, the tumour burden and the number of tumour nodules were much higher in the mice injected with FoxM1b Tg;Arf−/− HCC cells compared to the mice injected with Arf−/−HCC cells (Fig 2D and E), providing further evidence that FoxM1b, in the absence of its inhibitor Arf, drives metastasis of the tumour cells. FoxM1b activates AKT and induces an EMT-like phenotype The FoxM1b Tg;Arf−/− HCC cells show phenotypic changes reminiscent of EMT. The cells exhibited a spindle-shape morphology (Fig 3A) and expressed low levels of E-cadherin and high levels of the mesenchymal markers vimentin and α-SMA (Fig 3B). These differences were observed in all three independent lines. Also, similar results were observed in Maden–Darby Canine kidney (MDCK) epithelial cells, which are wildly used to study EMT and express negligible amount of Arf (Fig S2B of Supporting Information). We observed, however, that MDCK cells express Arf upon ultraviolet irradiation, suggesting that these cells do have the ability to induce Arf in response to stress signalling (Fig S2B of Supporting Information). Ectopic FoxM1 expression induced dramatic changes in cell morphology (Fig S2C of Supporting Information). Interestingly, we observed increased Akt kinase activity in FoxM1b Tg;Arf−/− cells compared to Arf−/− cells (Fig 3C). Akt has been shown to induce EMT by transcriptional repression of E-cadherin (Grille et al, 2003). glycogen synthase kinase-3 beta (GSK-3β) is a target of Akt and inactivates the transcriptional repressor Snail, a potent inducer of EMT (Zhou et al, 2004). As expected, we observed increased inhibitory phosphorylation of GSK-3β and increased Snail expression in FoxM1b Tg;Arf−/− cells (Fig 3C). Similar results were observed in the MDCK cells (Fig S2D of Supporting Information). Our observations suggest that FoxM1b induces an EMT-like phenotype by activating the Akt-Snail pathway. Figure 3. FoxM1b Tg;Arf−/− cells exhibit morphological changes reminiscent of EMT. A.. Representative phase-contrast images of the cells are shown. Magnification: ×200. B.. Expression of EMT markers was determined by immunoblotting. β-Actin served as a loading control. C.. Activation of AKT/GSK-3β/Snail pathway was assessed by immunoblotting. D.. Invasion assays were performed as described in the Materials and Methods Section. E.. Arf−/− HCC cells were infected with adenovirus-expressing GFP or FoxM1b for 48 h and subjected to invasion assay. Data are expressed as mean ± SD (*p < 0.05). Download figure Download PowerPoint Previous in vitro studies indicated that over-expression of FoxM1b could stimulate cell migration/invasion (Dai et al, 2007; Liu et al, 2006). However, the mechanism remains to be elucidated. Recent studies indicate that invasion of cancer cells are critically associated with the acquisition of EMT phenotypes (Kang & Massague, 2004; Thiery et al, 2009; Yang et al, 2004). Therefore, it is likely that the EMT-like changes induced by FoxM1b contribute to tumour cell invasion. As expected, the HCC cells derived from the FoxM1b Tg;Arf−/− mice were significantly more invasive compared to those from the Arf−/− mice (Fig 3D). Moreover, over-expression of FoxM1b in the Arf−/− HCC cells stimulated EMT-like changes in cells (Fig S2E and F of Supporting Information) and increased invasiveness of the tumour cells (Fig 3E). FoxM1b stimulates Stathmin and destabilizes microtubule To further investigate the mechanism of the increased cell invasiveness, we considered Stathmin because it was demonstrated that the MT-destabilizing activity of Stathmin plays significant roles in cell migration and invasion (Baldassarre et al, 2005). All of the six FoxM1b Tg;Arf−/− tumour samples displayed greatly elevated expression of Stathmin compared to the samples from the Arf−/− tumours (Fig S3A of Supporting Information). Moreover, we found that FoxM1 directly bound to the promoter of the Stathmin gene, as judged by chromatin-IP assays (Fig S3B of Supporting Information). Stathmin was shown to increase cell migration by destabilizing MTs. Therefore, we compared the MT-destabilizing activity in the HCC cells using a tubulin dilution assay. While they express comparable levels of total tubulin, FoxM1b Tg;Arf−/− cells contained much lower levels of MT after the tubulin dilution (Fig S3C and D of Supporting Information), which is consistent with the increased expression of Stathmin. Thus, FoxM1b stimulates multiple mechanisms to increase invasiveness of the tumour cells. FoxM1b stimulates lysyl oxidase expression and pre-metastatic niche formation We determined expression of various metastasis genes in FoxM1b Tg;Arf−/− and Arf−/− liver tumours. Total RNA extracted from tumour samples was analysed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Previous in vitro studies demonstrated that FoxM1b could stimulate expression of matrix metalloprotease MMP2 and the pro-angiogenic factor vascular endothelial growth factor (VEGF) (Dai et al, 2007; Joyce & Pollard, 2009; Li et al, 2009; Zhang et al, 2008). We observed increased expression of those genes, as well as increased expression of MT1-MMP in FoxM1b Tg;Arf−/− liver samples (Fig S4 of Supporting Information). Interestingly, we also observed elevated expression of PDGF-C in FoxM1b Tg;Arf−/− tumour samples. PDGF-C has been reported to be a potent mitogen for hepatic stellate cells (HSCs), which leads to hepatic fibrosis and HCC (Campbell et al, 2005). Therefore, it is conceivable that sustained production of high level PDGF-C in FoxM1b Tg;Arf−/− mice activates HSC proliferation, causing increase in collagen deposition and subsequent hepatic fibrosis. In addition, we found that the chemokine receptor CXCR4, which is involved in tumour cell-homing, was up-regulated in the FoxM1b Tg;Arf−/− tumour samples. Increased expression of LOX has been implicated in tumour cell invasiveness and tumour metastasis (Akiri et al, 2003; Erler et al, 2006; Sakai et al, 2009). Interestingly, we found that LOX, LOXL2 and LOXL3 were expressed at higher levels in FoxM1 Tg;Arf−/− liver tumours than in Arf−/− tumours (Fig 4A). Also, FoxM1b Tg;Arf−/− HCC cells expressed substantially higher levels of LOX and LOXL2 than Arf−/− cells (Fig 4B and C). Moreover, over-expression of FoxM1b stimulated expression of LOX and LOXL2 mRNA (Fig 4D and E). Chromatin immunoprecipitation (ChIP) assays further confirmed that FoxM1b directly binds to the promoter region of LOX and LOXL2 (Fig 4F and G). A more detailed ChIP experiment is included in Fig S5 of Supporting Information. Figure 4. FoxM1b Tg;Arf−/− HCCs express LOX at higher levels compared to Arf−/− HCCs. A.. Semi-quantitative RT-PCR was performed using total RNA from liver tumours. B-E.. Quantitative RT-PCR was performed to determine mRNA levels of LOX and LOXL2. D,E.. Arf−/− HCC cells were infected with adenovirus expressing GFP or FoxM1b for 48 h. Data are expressed as mean ± SD (*p < 0.05; **p < 0.01). F,G.. Chromatin-immunoprecipitation (ChIP) assays were performed using a monoclonal antibody against T7-epitope to detect specific binding of FoxM1b to LOX (F) and LOXL2 (G) promoters in T7-FoxM1b-transfected Sk-hep1 cells. Download figure Download PowerPoint It was shown that LOX secreted from primary tumours accumulates at tar" @default.
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• W1840802607 title "Deregulation of FoxM1b leads to tumour metastasis" @default.
• W1840802607 cites W1964081206 @default.
• W1840802607 cites W1966056249 @default.
• W1840802607 cites W1968445925 @default.
• W1840802607 cites W1971481045 @default.
• W1840802607 cites W1974574293 @default.
• W1840802607 cites W1979147887 @default.
• W1840802607 cites W1983109993 @default.
• W1840802607 cites W1985921109 @default.
• W1840802607 cites W1987986416 @default.
• W1840802607 cites W1993203583 @default.
• W1840802607 cites W1994242450 @default.
• W1840802607 cites W2009736768 @default.
• W1840802607 cites W2011833926 @default.
• W1840802607 cites W2012247886 @default.
• W1840802607 cites W2013024419 @default.
• W1840802607 cites W2014756186 @default.
• W1840802607 cites W2033363278 @default.
• W1840802607 cites W2036008499 @default.
• W1840802607 cites W2042521915 @default.
• W1840802607 cites W2045035317 @default.
• W1840802607 cites W2051787132 @default.
• W1840802607 cites W2062265555 @default.
• W1840802607 cites W2069140606 @default.
• W1840802607 cites W2070058781 @default.
• W1840802607 cites W2074867550 @default.
• W1840802607 cites W2076880106 @default.
• W1840802607 cites W2092909221 @default.
• W1840802607 cites W2102353246 @default.
• W1840802607 cites W2116170706 @default.
• W1840802607 cites W2122129759 @default.
• W1840802607 cites W2122401755 @default.
• W1840802607 cites W2124618775 @default.
• W1840802607 cites W2126663928 @default.
• W1840802607 cites W2130512685 @default.
• W1840802607 cites W2137035181 @default.
• W1840802607 cites W2137449882 @default.
• W1840802607 cites W2138897067 @default.
• W1840802607 cites W2150608281 @default.
• W1840802607 cites W2151909352 @default.
• W1840802607 cites W2154589460 @default.
• W1840802607 cites W2155890719 @default.
• W1840802607 cites W2156122059 @default.
• W1840802607 cites W2158838322 @default.
• W1840802607 cites W2159744630 @default.
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