| 1. |
- Arjonen, Antti, et al.
(author)
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Mutant p53-associated myosin-X upregulation promotes breast cancer invasion and metastasis
- 2014
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In: Journal of Clinical Investigation. - : American Society for Clinical Investigation. - 0021-9738 .- 1558-8238. ; 124:3, s. 1069-1082
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Journal article (peer-reviewed)abstract
- Mutations of the tumor suppressor TP53 are present in many forms of human cancer and are associated with increased tumor cell invasion and metastasis. Several mechanisms have been identified for promoting dissemination of cancer cells with TP53 mutations, including increased targeting of integrins to the plasma membrane. Here, we demonstrate a role for the filopodia-inducing motor protein Myosin-X (Myo10) in mutant p53-driven cancer invasion. Analysis of gene expression profiles from 2 breast cancer data sets revealed that MYO10 was highly expressed in aggressive cancer subtypes. Myo10 was required for breast cancer cell invasion and dissemination in multiple cancer cell lines and murine models of cancer metastasis. Evaluation of a Myo10 mutant without the integrin-binding domain revealed that the ability of Myo10 to transport 131 integrins to the filopodia tip is required for invasion. Introduction of mutant p53 promoted Myo10 expression in cancer cells and pancreatic ductal adenocarcinoma in mice, whereas suppression of endogenous mutant p53 attenuated Myo10 levels and cell invasion. In clinical breast carcinomas, Myo10 was predominantly expressed at the invasive edges and correlated with the presence of TP53 mutations and poor prognosis. These data indicate that Myo10 upregulation in mutant p53-driven cancers is necessary for invasion and that plasma-membrane protrusions, such as filopodia, may serve as specialized metastatic engines.
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| 2. |
- Bandaru, Sashidar, et al.
(author)
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Targeting filamin B induces tumor growth and metastasis via enhanced activity of matrix metalloproteinase-9 and secretion of VEGF-A : Role of filamin in tumor growth.
- 2014
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In: Oncogenesis. - : Springer Science and Business Media LLC. - 2157-9024. ; 3
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Journal article (peer-reviewed)abstract
- Filamins regulate cell locomotion and associate with diverse signaling molecules. We have recently found that targeting filamin A (FLNA) reduces RAS-induced lung adenocarcinomas. In this study, we explored the role of another major filamin isoform, filamin B (FLNB), in tumor development. In contrast to FLNA, we report that targeting FLNB enhances RAS-induced tumor growth and metastasis which is associated with higher matrix metallopeptidase-9 (MMP-9) and extracellular signal-regulated kinase (ERK) activity. Flnb deficiency in mouse embryonic fibroblasts results in increased proteolytic activity of MMP-9 and cell invasion mediated by the RAS/ERK pathway. Similarly, silencing FLNB in multiple human cancer cells increases the proteolytic activity of MMP-9 and tumor cell invasion. Furthermore, we observed that Flnb-deficient RAS-induced tumors display more capillary structures that is correlated with increased vascular endothelial growth factor-A (VEGF-A) secretion. Inhibition of ERK activation blocks phorbol myristate acetate-induced MMP-9 activity and VEGF-A secretion in vitro. In addition, silencing FLNB in human ovarian cancer cells increases secretion of VEGF-A that induces endothelial cells to form more vascular structures in vitro. We conclude that FLNB suppresses tumor growth and metastasis by regulating the activity of MMP-9 and secretion of VEGF-A which is mediated by the RAS/ERK pathway.
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| 3. |
- Cao, Ziquan, et al.
(author)
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Hypoxia-induced retinopathy model in adult zebrafish
- 2010
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In: Nature Protocols. - : Nature Publishing Group. - 1754-2189 .- 1750-2799. ; 5:12, s. 1903-1910
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Journal article (peer-reviewed)abstract
- Hypoxia-induced vascular responses, including angiogenesis, vascular remodeling and vascular leakage, significantly contribute to the onset, development and progression of retinopathy. However, until recently there were no appropriate animal disease models recapitulating adult retinopathy available. In this article, we describe protocols that create hypoxia-induced retinopathy in adult zebrafish. Adult fli1: EGFP zebrafish are placed in hypoxic water for 3-10 d and retinal neovascularization is analyzed using confocal microscopy. It usually takes 11 d to obtain conclusive results using the hypoxia-induced retinopathy model in adult zebrafish. This model provides a unique opportunity to study kinetically the development of retinopathy in adult animals using noninvasive protocols and to assess therapeutic efficacy of orally active antiangiogenic drugs.
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| 4. |
- Dahl Jensen, Lasse, et al.
(author)
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Zebrafish Models to Study Hypoxia-Induced Pathological Angiogenesis in Malignant and Nonmalignant Diseases
- 2011
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In: Birth Defects Research. Part C: Embryo Today Reviews. - : John Wiley and Sons.Ltd. - 1542-975X .- 1542-9768. ; 93:2, s. 182-193
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Research review (peer-reviewed)abstract
- Most in vivo preclinical disease models are based on mouse and other mammalian systems. However, these rodent-based model systems have considerable limitations to recapitulate clinical situations in human patients. Zebrafish have been widely used to study embryonic development, behavior, tissue regeneration, and genetic defects. Additionally, zebrafish also provides an opportunity to screen chemical compounds that target a specific cell population for drug development. Owing to the availability of various genetically manipulated strains of zebrafish, immune privilege during early embryonic development, transparency of the embryos, and easy and precise setup of hypoxia equipment, we have developed several disease models in both embryonic and adult zebrafish, focusing on studying the role of angiogenesis in pathological settings. These zebrafish disease models are complementary to the existing mouse models, allowing us to study clinically relevant processes in cancer and nonmalignant diseases, which otherwise would be difficult to study in mice. For example, dissemination and invasion of single human or mouse tumor cells from the primary site in association with tumor angiogenesis can be studied under normoxia or hypoxia in zebrafish embryos. Hypoxia-induced retinopathy in the adult zebrafish recapitulates the clinical situation of retinopathy development in diabetic patients or age-related macular degeneration. These zebrafish disease models offer exciting opportunities to understand the mechanisms of disease development, progression, and development of more effective drugs for therapeutic intervention.
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| 5. |
- Hosaka, Kayoko, et al.
(author)
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Tumour PDGF-BB expression levels determine dual effects of anti-PDGF drugs on vascular remodelling and metastasis
- 2013
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In: Nature Communications. - : Nature Publishing Group: Nature Communications. - 2041-1723. ; 4:2129
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Journal article (peer-reviewed)abstract
- Anti-platelet-derived growth factor (PDGF) drugs are routinely used in front-line therapy for the treatment of various cancers, but the molecular mechanism underlying their dose-dependent impact on vascular remodelling remains poorly understood. Here we show that anti-PDGF drugs significantly inhibit tumour growth and metastasis in high PDGF-BB-producing tumours by preventing pericyte loss and vascular permeability, whereas they promote tumour cell dissemination and metastasis in PDGF-BB-low-producing or PDGF-BB-negative tumours by ablating pericytes from tumour vessels. We show that this opposing effect is due to PDGF-beta signalling in pericytes. Persistent exposure of pericytes to PDGF-BB markedly downregulates PDGF-beta and inactivation of the PDGF-beta signalling decreases integrin alpha 1 beta 1 levels, which impairs pericyte adhesion to extracellular matrix components in blood vessels. Our data suggest that tumour PDGF-BB levels may serve as a biomarker for selection of tumour-bearing hosts for anti-PDGF therapy and unsupervised use of anti-PDGF drugs could potentially promote tumour invasion and metastasis.
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| 6. |
- Lee, Samantha Lin Chiou, et al.
(author)
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Hypoxia-induced pathological angiogenesis mediates tumor cell dissemination, invasion, and metastasis in a zebrafish tumor model
- 2009
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:46, s. 19485-19490
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Journal article (peer-reviewed)abstract
- Mechanisms underlying pathological angiogenesis in relation to hypoxia in tumor invasion and metastasis remain elusive. Here, we have developed a zebrafish tumor model that allows us to study the role of pathological angiogenesis under normoxia and hypoxia in arbitrating early events of the metastatic cascade at the single cell level. Under normoxia, implantation of a murine T241 fibrosarcoma into the perivitelline cavity of developing embryos of transgenic fli1:EGFP zebrafish did not result in significant dissemination, invasion, and metastasis. In marked contrast, under hypoxia substantial tumor cells disseminated from primary sites, invaded into neighboring tissues, and metastasized to distal parts of the fish body. Similarly, expression of the hypoxia-regulated angiogenic factor, vascular endothelial growth factor (VEGF) to a high level resulted in tumor cell dissemination and metastasis, which correlated with increased tumor neovascularization. Inhibition of VEGF receptor signaling pathways by sunitinib or VEGFR2 morpholinos virtually completely ablated VEGF-induced tumor cell dissemination and metastasis. To the best of our knowledge, hypoxia- and VEGF-induced pathological angiogenesis in promoting tumor dissemination, invasion, and metastasis has not been described perviously at the single cell level. Our findings also shed light on molecular mechanisms of beneficial effects of clinically available anti-VEGF drugs for cancer therapy.
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| 7. |
- Pudelko, Linda, et al.
(author)
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Glioblastoma and glioblastoma stem cells are dependent on functional MTH1
- 2017
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In: Oncotarget. - : Impact Journals LLC. - 1949-2553. ; 8:49, s. 84671-84684
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Journal article (peer-reviewed)abstract
- Glioblastoma multiforme (GBM) is an aggressive form of brain cancer with poor prognosis. Cancer cells are characterized by a specific redox environment that adjusts metabolism to its specific needs and allows the tumor to grow and metastasize. As a consequence, cancer cells and especially GBM cells suffer from elevated oxidative pressure which requires antioxidant-defense and other sanitation enzymes to be upregulated. MTH1, which degrades oxidized nucleotides, is one of these defense enzymes and represents a promising cancer target. We found MTH1 expression levels elevated and correlated with GBM aggressiveness and discovered that siRNA knock-down or inhibition of MTH1 with small molecules efficiently reduced viability of patient-derived GBM cultures. The effect of MTH1 loss on GBM viability was likely mediated through incorporation of oxidized nucleotides and subsequent DNA damage. We revealed that MTH1 inhibition targets GBM independent of aggressiveness as well as potently kills putative GBM stem cells in vitro. We used an orthotopic zebrafish model to confirm our results in vivo and light-sheet microscopy to follow the effect of MTH1 inhibition in GBM in real time. In conclusion, MTH1 represents a promising target for GBM therapy and MTH1 inhibitors may also be effective in patients that suffer from recurring disease.
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| 8. |
- Rouhi, Pegah, et al.
(author)
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Hypoxia-induced metastasis model in embryonic zebrafish
- 2010
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In: Nature Protocols. - : Nature Publishing Group. - 1754-2189 .- 1750-2799. ; 5:12, s. 1911-1918
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Journal article (peer-reviewed)abstract
- Hypoxia facilitates tumor invasion and metastasis by promoting neovascularization and co-option of tumor cells in the peritumoral vasculature, leading to dissemination of tumor cells into the circulation. However, until recently, animal models and imaging technology did not enable monitoring of the early events of tumor cell invasion and dissemination in living animals. We recently developed a zebrafish metastasis model to dissect the detailed events of hypoxia-induced tumor cell invasion and metastasis in association with angiogenesis at the single-cell level. In this model, fluorescent DiI-labeled human or mouse tumor cells are implanted into the perivitelline cavity of 48-h-old zebrafish embryos, which are subsequently placed in hypoxic water for 3 d. Tumor cell invasion, metastasis and pathological angiogenesis are detected under fluorescent microscopy in the living fish. The average experimental time for this model is 7 d. Our protocol offers a remarkable opportunity to study molecular mechanisms of hypoxia-induced cancer metastasis.
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| 9. |
- Rouhi, Pegah, et al.
(author)
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Pathological angiogenesis facilitates tumor cell dissemination and metastasis
- 2010
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In: Cell Cycle. - : Landes Bioscience. - 1538-4101 .- 1551-4005. ; 9:5, s. 913-917
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Journal article (peer-reviewed)abstract
- Clinically detectable metastases represent an ultimate consequence of the metastatic cascade that consists of distinct processes including tumor cell invasion, dissemination, metastatic niche formation, and re-growth into a detectable metastatic mass. Although angiogenesis is known to promote tumor growth, its role in facilitating early events of the metastatic cascade remains poorly understood. We have recently developed a zebrafish tumor model that enables us to study involvement of pathological angiogenesis in tumor invasion, dissemination and metastasis. This non-invasive in vivo model allows detection of single malignant cell dissemination under both normoxia and hypoxia. Further, hypoxia-induced VEGF significantly facilitates tumor cell invasion and dissemination. These findings demonstrate that VEGF-induced pathological angiogenesis is essential for tumor dissemination and further corroborates potentially beneficial effects of clinically ongoing anti-VEGF drugs for the treatment of various malignancies.
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| 10. |
- Rouhi, Pegah
(author)
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Role of angiogenesis in cancer invasion and metastasis
- 2013
-
Doctoral thesis (other academic/artistic)abstract
- Cancer metastasis is a complex process that involves an elaborate interplay between malignant cells and various host cellular and molecular components. The metastatic cascade consists of several discrete but non-separable steps, including: 1) malignant transformation of cells; 2) intravasation and dissemination of tumor cells into the circulation or lymphatic system; 3) transport of malignant cells to distal organs and tissues; 4) adherence of tumor cells to distal sites; 5) formation of the initial metastatic niches, and 6) angiogenesis-dependent re-growth of metastatic foci to clinically detectable tumors. Despite technological advances, advanced image analyses only allow detection of a relatively large tumor-mass in human cancer patients and in various animal models. Hypoxia is one of the characteristic features of the tumor microenvironment and low oxygen is known to induce tumor angiogenesis. However, the causal link between tumor hypoxia and tumor invasion remains elusive. In this thesis work, we have developed a novel zebrafish model that allows us to investigate tumor invasion at the single cell level in living animals. Furthermore, exposure of the zebrafish in hypoxic water permits us to study the role of hypoxia in facilitating tumor invasion at the early stage of the metastatic cascade. We further investigated hypoxia-regulated genes in tumors that contribute to metastasis. In paper I, we developed a novel zebrafish model to study metastasis at the single cell level in living animals. We take advantage of the transparent nature of zebrafish embryos that are immune privileged at the early stage of development. Additionally, the availability of a transgenic zebrafish line that expresses enhanced green fluorescent protein allows us to study the interaction between tumor cells and the vasculature in a non-invasive manner. We also developed a novel hypoxia chamber in which oxygen levels in the aquarium can be adjusted to a certain desired level. Development of these novel methods allows us to study the early events of cancer metastasis, which otherwise cannot be visualized in mammalian systems. In paper II, we studied the role of hypoxia in promoting metastasis using the method described in Paper I. We have found that hypoxia induces angiogenesis in the implanted tumors and VEGF is the crucial mediator that is responsible for hypoxia-induced tumor angiogenesis. To further validate the role of VEGF in mediating tumor invasion and metastasis, blocking VEGFR signaling by tyrosine kinase inhibitors or specific morpholinos inhibits hypoxia-induced metastasis. Moreover, overexpression of VEGF in tumor cells also significantly promotes cancer metastasis through stimulation of tumor angiogenesis although VEGF lacks direct effects on tumor cells. These findings show that hypoxia plays a pivotal role in facilitating tumor cell dissemination at the early stage of the metastatic cascade and inhibition of the VEGF signaling might be an important approach for treatment of metastatic disease. In paper III, we show that a novel mechanism of hypoxia-induced angiogenesis, which involves in physical interaction between filamin A and HIF-1α. Hypoxia-induced cleavage of filamin A promotes nuclear accumulation of HIF-1α, leading to up-regulation of its target genes such as VEGF. Via this mechanism, filamin A stimulates tumor angiogenesis and tumor growth. In paper IV, we show that filamin B serves as a negative regulator for tumor invasion and metastasis. In filamin B deficient mice, increased metalloproteinase-9 (MMP-9) activity has been detected. Similarly, silencing of MMP-9 in various tumor models resulted in enhanced tumor angiogenesis and invasion by increasing the bioavailability of VEGF.
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| 11. |
- Zhao, Chunyan, et al.
(author)
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Genome-wide profiling of AP-1-regulated transcription provides insights into the invasiveness of triple-negative breast cancer.
- 2014
-
In: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 74:14, s. 3983-3994
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Journal article (peer-reviewed)abstract
- Triple-negative breast cancer (TNBC) is an aggressive clinical subtype accounting for up to 20% of all breast cancers, but its malignant determinants remain largely undefined. Here, we show that in TNBC the overexpression of Fra-1, a component of the transcription factor AP-1, offers prognostic potential. Fra-1 depletion or its heterodimeric partner c-Jun inhibits the proliferative and invasive phenotypes of TNBC cells in vitro. Similarly, RNAi-mediated attenuation of Fra-1 or c-Jun reduced cellular invasion in vivo in a zebrafish tumor xenograft model. Exploring the AP-1 cistrome and the AP-1-regulated transcriptome, we obtained insights into the transcriptional regulatory networks of AP-1 in TNBC cells. Among the direct targets identified for Fra-1/c-Jun involved in proliferation, adhesion, and cell-cell contact, we found that AP-1 repressed the expression of E-cadherin by transcriptional upregulation of ZEB2 to stimulate cell invasion. Overall, this work illuminates the pathways through which TNBC cells acquire invasive and proliferative properties.
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| 12. |
- Zheng, Xiaowei, et al.
(author)
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Hypoxia-induced and calpain-dependent cleavage of filamin-A regulates the hypoxic response. : Hypoxia-induced and calpain-dependent cleavage of filamin-A regulates the hypoxic response.
- 2014
-
In: Proceedings of the National Academy of Science of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 111:7, s. 2560-2565
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Journal article (peer-reviewed)abstract
- The cellular response to hypoxia is regulated by hypoxia-inducible factor-1α and -2α (HIF-1α and -2α). We have discovered that filamin A (FLNA), a large cytoskeletal actin-binding protein, physically interacts with HIF-1α and promotes tumor growth and angiogenesis. Hypoxia induces a calpain-dependent cleavage of FLNA to generate a naturally occurring C-terminal fragment that accumulates in the cell nucleus. This fragment interacts with the N-terminal portion of HIF-1α spanning amino acid residues 1-390 but not with HIF-2α. In hypoxia this fragment facilitates the nuclear localization of HIF-1α, is recruited to HIF-1α target gene promoters, and enhances HIF-1α function, resulting in up-regulation of HIF-1α target gene expression in a hypoxia-dependent fashion. These results unravel an important mechanism that selectively regulates the nuclear accumulation and function of HIF-1α and potentiates angiogenesis and tumor progression.
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