| 1. |
- Cunha, Sara I., et al.
(författare)
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Endothelial ALK1 Is a Therapeutic Target to Block Metastatic Dissemination of Breast Cancer.
- 2015
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Ingår i: Cancer Research. - 1538-7445 .- 0008-5472. ; 75:12, s. 2445-2456
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Tidskriftsartikel (refereegranskat)abstract
- Exploration of new strategies for the prevention of breast cancer metastasis is justifiably at the center of clinical attention. In this study, we combined a computational biology approach with mechanism-based preclinical trials to identify inhibitors of activin-like receptor kinase (ALK) 1 as effective agents for blocking angiogenesis and metastasis in breast cancer. Pharmacologic targeting of ALK1 provided long-term therapeutic benefit in mouse models of mammary carcinoma, accompanied by strikingly reduced metastatic colonization as a monotherapy or part of combinations with chemotherapy. Gene-expression analysis of breast cancer specimens from a population-based nested case-control study encompassing 768 subjects defined endothelial expression of ALK1 as an independent and highly specific prognostic factor for metastatic manifestation, a finding that was corroborated in an independent clinical cohort. Overall, our results suggest that pharmacologic inhibition of endothelial ALK1 constitutes a tractable strategy for interfering with metastatic dissemination of breast cancer. Cancer Res; 75(12); 2445-56. ©2015 AACR.
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| 2. |
- Eleftheriou, Nikolas, et al.
(författare)
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Entrapment of Living Bacterial Cells in Low-Concentration Silica Materials Preserves Cell Division and Promoter Regulation
- 2013
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 25:23, s. 4798-4805
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Tidskriftsartikel (refereegranskat)abstract
- The entrapment of bacterial cells within inorganic silica materials was reported almost 20 years ago. However, almost all studies to date have shown that these entrapped cells are unable to divide and thus should be expected to have reduced promoter activity. In view of the importance of bacteria as model systems for both fundamental and applied biological studies, it is crucial that immobilized cells retain solutionlike properties, including the ability to divide and display normal promoter activity. Herein we report on a method to immobilize bacterial cells within low-density inorganic silica-based materials, where the cells retain both cell division and promoter activity. Sol gel processing was used to entrap Escherichia coli cells carrying a variety of green fluorescent protein-linked promoters into sodium silicate-derived materials that were formed in microwell plates. Using a series of assays, we were able to demonstrate that (1) the entrapped cells can divide within the pores of the silica matrix, (2) cellular pathways are regulated in a similar manner in both solution and the sol-gel-derived materials, and (3) promoters in entrapped cells can be specifically induced with small molecules (e.g., antimicrobial compounds) in a concentration-dependent manner to allow assessment of both potency and mode of action. This solid-phase assay system was tested using multiple antimicrobial pathways and should enable the development of solid-phase assays for the discovery of new small molecules that are active against bacteria.
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| 3. |
- Eleftheriou, Nikolas M., et al.
(författare)
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Compound genetically engineered mouse models of cancer reveal dual targeting of ALK1 and endoglin as a synergistic opportunity to impinge on angiogenic TGF-β signaling
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:51, s. 84314-84325
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis occurs early in tumor development, sustains primary tumor growth and provides a route for metastatic escape. The TGF-β family receptors modulate angiogenesis via endothelial-cell specific pathways. Here we investigate the interaction of two such receptors, ALK1 and endoglin, in pancreatic neuroendocrine tumors (PanNET). Independently, ALK1 and endoglin deficiencies exhibited genetically divergent phenotypes, while both highly correlate to an endothelial metagene in human and mouse PanNETs. A concurrent deficiency of both receptors synergistically decreased tumor burden to a greater extent than either individual knockdown. Furthermore, the knockout of Gdf2 (BMP9), the primary ligand for ALK1 and endoglin, exhibited a mixed phenotype from each of ALK1 and endoglin deficiencies; overall primary tumor burden decreased, but hepatic metastases increased. Tumors lacking BMP9 display a hyperbranching vasculature, and an increase in vascular mesenchymal-marker expression, which may be implicit in the increase in metastases. Taken together, our work cautions against singular blockade of BMP9 and instead demonstrates the utility of dual blockade of ALK1 and endoglin as a strategy for antiangiogenic therapy in PanNET.
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| 4. |
- Eleftheriou, Nikolas
(författare)
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TGF-β Family Signaling in Tumor Angiogenesis
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis provides growing tumors a source of nutrients and oxygen, and a route for metastatic dissemination. In recent years anti-angiogenic therapies that primarily target the vascular endothelial growth factor (VEGF) signaling cascade have entered the clinic. However in practice, these have encountered unexpected mechanisms of resistance in many solid tumors, highlighting the need for further understanding of the basic biology behind alternative signaling pathways that drive angiogenesis. The transforming growth factor (TGF)-β superfamily of ligands and receptors are critical for vascular development and are widely implicated in cancer. Here we investigate the TGF-β signaling activity through endothelial cells (EC), including their impact on tumor angiogenesis and metastatic dissemination, through genetic modification and therapeutic inhibition.In papers I, II and IV we investigated the in vivo activing receptor-like kinase (ALK)1/bone morphogenetic protein (BMP)9 signaling axis in various mouse models of cancer. ALK1-Fc, a soluble ALK1 receptor domain ligand trap for BMP9 and BMP10, was evaluated in preclinical models of pancreatic and breast cancer, showing a decrease in angiogenesis, tumor growth and number of metastases. These reductions were enhanced when combined with chemotherapy. In the adjuvant setting, ALK1-Fc had fewer metastases in orthotopic breast cancer cell models following tumor resection. Combined deficiency of the genes encoding ALK1 and endoglin synergistically decreased the volume of pancreatic neuroendocrine tumors, whereas BMP9 knockout mice display decrease in primary tumor burden, but an increase in vessel hypersprouting and hepatic micrometastases.In papers III and IV we investigated the roles of ALK5 and TGFBR2 in pancreatic neuroendocrine tumor models with genetic modifications limited to endothelial cells (EC). Mice undergo EC-specific recombination prior to the tumor angiogenic switch for deletion of TGFBR2, ALK5, or expression of a constitutively active ALK5 mutant. EC deletion of ALK5 induced blood vessel hypersprouting in tumors and increased lymph node metastases, whereas constitutive activation of ALK5 in ECs increased hepatic metastases. TGFBR2 deletion in ECs strongly inhibits tumorigenesis, decreasing the number of tumors and tumor volume, and tumors presented with highly irregular vasculature.Our studies emphasize the impact of TGF-β signaling on tumor angiogenesis and metastatic dissemination, and this pathway presents potential targets in the development of clinical therapies. However the mechanism of action following pathway inhibition remains unclear, and further investigation is warranted.
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| 5. |
- Ge, Xin, et al.
(författare)
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Sol-Gel-Derived Materials for Production of Pin-Printed Reporter Gene Living-Cell Microarrays
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 85:24, s. 12108-12117
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Tidskriftsartikel (refereegranskat)abstract
- We report the fabrication of three-dimensional living-cell microarrays via pin-printing of soft sol-gel-derived silica materials containing bacterial cells. Bacterial cells entrapped in the silica-glycerol microarray spots can express reporter genes and produce strong fluorescence signals. The signals responded to the presence and concentration of inducers or repressors as expected, indicating that the entrapped cells remained metabolically active. Microscopic imaging of individual microarray spots at different culture times suggests that the entrapped cells can grow and divide, phenomena further confirmed by experiments in bulk sol-gel materials that demonstrated the increases of entrapped cell density and fluorescence during incubation in culture media. The cell microarrays can also be printed into 96-well glass bottom microtiter plates in a multiplexed manner, and the fluorescence signals generated were able to quantitatively and selectively respond to the concentration of inducers, thus demonstrating the potential for multitarget biosensing and high-throughput/high-content cell-based screening. The signal levels of bacterial cells in silica were significantly higher than those in alginate arrays, presumably due to viability of the entrapped cells in silica sol-gels. Microarray stability assays proved that the entrapped cells retained their physiological activity after storage for four weeks. Given that a large number of fluorescent and luminescent protein-based cell assays have been developed, the reporter gene living-cell microarrays demonstrated in this paper are expected to be applicable to a wide variety of research areas ranging from bioanalysis and chemical biology to drug discovery and probing of cell-material interactions.
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