Kämmerer, Elke (2014)
Influence of the extracellular matrix on
cellular behaviour – Development and
application of a bioengineered 3D cell
culture system for cancer research and high
resolution microscopy.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
The aim of this thesis was the application and establishment of a semi-synthetic, bioengineered model system for ovarian cancer and a naturally based, optimised hydrogel system for non-invasive high resolution microscopy analysis of plasma membrane dynamics in a physiological relevant microenvironment. Providing ex vivo models for cancer research with physiologically relevant 3D conditions combined with controllable physical and chemical composition is an ongoing challenge in the field of tissue engineering and cell biology. In this study a semi-synthetic GelMA-based hydrogel system was successfully applied to the study of ovarian cancer cells. Thereby GelMA provided a biomaterial approach combining natural binding and cleavage sites with tuneable properties in an easy to handle and cost-effective hydrogel system. Using this model system, the unique metastatic pattern of ovarian cancer, found in patients with late stage disease, was replicated in vitro and in vivo. The polymer concentration (2.5-7% w/v) did directly impact the hydrogel stiffness (0.5± 0.2 kPa – 8.9 kPa ± 1.8 kPa) but had only minor impact on solute diffusion. Diffusion of FITC labelled 70 kDa dextran was in all tested hydrogels (2.5-7% w/v; 29.9±3.3 till 16.9 μm2/s) close to the diffusion coefficient measured in water (39.2 ± 2.8 μm2/s). In the stiffest tested hydrogel the diffusion coefficient was decreased by only 2.3 times. Spheroid formation, occurring in the tumour fluid (ascites) of ovarian cancer patients with late stage disease, combined with the highest metabolic and proliferation rates was reflected in medium stiff hydrogels (5%, 3.4 kPa). Inhibition of hydrogel degradation, with a MMP inhibitor, reduced spheroid growth and metabolic activity. Additional ECM components, Laminin-411 and hyaluronic acid increased spheroid growth, metabolic and proliferation activity significantly. Furthermore this hydrogel system allowed bio-molecular analysis of mRNA and protein levels. Ovarian cancer cells showed an increased mRNA level of integrin β1 compared to monolayer or other 3D cultures. Next to the ex vivo experiments it was shown that GelMA-based hydrogels can be successfully used as spheroid-based cancer cell carrier system for in vivo studies. Spheroid-seeded hydrogels were intraperioteneally implanted into female NOD/SCID mice, resulting in tumour development and metastasis, known from the clinical sequence of the disease. The developed tumours showed a response rate of 33% to the anti-cancer drug paclitaxel, but not the integrin antagonist ATN-161. Combined treatment using both therapeutics resulted in 37.8% treatment response, while treatment with ATN-161 alone had no effect.Collagen-based hydrogel systems are widely used for investigations of cell-ECM crosstalk; however, they often lack reproducible, well characterised properties and are mostly not suitable for high resolution microscopy. A small volume collagen-based hydrogel system provided a 3D cell culture model utilised for high resolution microscopy approaches with optimised sample properties, such as sample immobilisation and minimised sample thickness. This study provided evidence of an alternative fluorescent labelling of collagen fibres after hydrogel polymerisation with E133 and Sirius Red. In particular E133 was a cost and timeeffective staining method, compatible with single photon CLSM and simultaneous cell-ECM imaging. Diffusion through collagen-based hydrogels was affected by surface properties of the diffusive particles rather than a size exclusive filtering. Carboxylated mircospheres (Ø 20 nm) did not diffuse through the hydrogel pores; they showed a high binding affinity towards collagen fibres. Also after 72 h, a gradient from the outer hydrogel parts to the centre was observable. This small volume collagen-based hydrogel system allowed culture of 4 different cell lines, showing high cell viability and being suitable for short and long term cultures. Compared to 2D cultures, adherent cell lines showed a different morphology in 3D, while non-adherent K562 cells did not show a morphological change. Studies on COS7 cells showed that next to morphology also cytoskeleton organisation was a function of the local microenvironment. In contrast, no differences in the intracellular organelle organisation between cells cultured in 2D or 3D was observed. Additionally this small volume collagenbased hydrogel system was suitable for single molecule microscopy measurements using the lipid like tracer molecule CellMask™Orange; a specific probe for plasma membrane labelling without biological function. This model system, combined with confined HILO excitation and a customised algorithm allowed single molecule microscopy also in a more complex, 3D microenvironment. Overall it was shown that mimicking a more natural, bioengineered microenvironment in a realistic experimental model can deepen the understanding of cancer cell behaviour and reaction to anti-cancer treatment. Moreover a 3D microenvironment does not exclude quantitative molecular assessment using single molecule microscopy, but therefore model system and analysis methods had to be adapted to this more complex situation.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2014 | ||||
Autor(en): | Kämmerer, Elke | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Influence of the extracellular matrix on cellular behaviour – Development and application of a bioengineered 3D cell culture system for cancer research and high resolution microscopy | ||||
Sprache: | Englisch | ||||
Referenten: | Meckel , PD Dr. Tobias ; Thiel, Prof. Dr. Gerhard | ||||
Publikationsjahr: | 2014 | ||||
Datum der mündlichen Prüfung: | 5 September 2014 | ||||
URL / URN: | http://tuprints.ulb.tu-darmstadt.de/4181 | ||||
Kurzbeschreibung (Abstract): | The aim of this thesis was the application and establishment of a semi-synthetic, bioengineered model system for ovarian cancer and a naturally based, optimised hydrogel system for non-invasive high resolution microscopy analysis of plasma membrane dynamics in a physiological relevant microenvironment. Providing ex vivo models for cancer research with physiologically relevant 3D conditions combined with controllable physical and chemical composition is an ongoing challenge in the field of tissue engineering and cell biology. In this study a semi-synthetic GelMA-based hydrogel system was successfully applied to the study of ovarian cancer cells. Thereby GelMA provided a biomaterial approach combining natural binding and cleavage sites with tuneable properties in an easy to handle and cost-effective hydrogel system. Using this model system, the unique metastatic pattern of ovarian cancer, found in patients with late stage disease, was replicated in vitro and in vivo. The polymer concentration (2.5-7% w/v) did directly impact the hydrogel stiffness (0.5± 0.2 kPa – 8.9 kPa ± 1.8 kPa) but had only minor impact on solute diffusion. Diffusion of FITC labelled 70 kDa dextran was in all tested hydrogels (2.5-7% w/v; 29.9±3.3 till 16.9 μm2/s) close to the diffusion coefficient measured in water (39.2 ± 2.8 μm2/s). In the stiffest tested hydrogel the diffusion coefficient was decreased by only 2.3 times. Spheroid formation, occurring in the tumour fluid (ascites) of ovarian cancer patients with late stage disease, combined with the highest metabolic and proliferation rates was reflected in medium stiff hydrogels (5%, 3.4 kPa). Inhibition of hydrogel degradation, with a MMP inhibitor, reduced spheroid growth and metabolic activity. Additional ECM components, Laminin-411 and hyaluronic acid increased spheroid growth, metabolic and proliferation activity significantly. Furthermore this hydrogel system allowed bio-molecular analysis of mRNA and protein levels. Ovarian cancer cells showed an increased mRNA level of integrin β1 compared to monolayer or other 3D cultures. Next to the ex vivo experiments it was shown that GelMA-based hydrogels can be successfully used as spheroid-based cancer cell carrier system for in vivo studies. Spheroid-seeded hydrogels were intraperioteneally implanted into female NOD/SCID mice, resulting in tumour development and metastasis, known from the clinical sequence of the disease. The developed tumours showed a response rate of 33% to the anti-cancer drug paclitaxel, but not the integrin antagonist ATN-161. Combined treatment using both therapeutics resulted in 37.8% treatment response, while treatment with ATN-161 alone had no effect.Collagen-based hydrogel systems are widely used for investigations of cell-ECM crosstalk; however, they often lack reproducible, well characterised properties and are mostly not suitable for high resolution microscopy. A small volume collagen-based hydrogel system provided a 3D cell culture model utilised for high resolution microscopy approaches with optimised sample properties, such as sample immobilisation and minimised sample thickness. This study provided evidence of an alternative fluorescent labelling of collagen fibres after hydrogel polymerisation with E133 and Sirius Red. In particular E133 was a cost and timeeffective staining method, compatible with single photon CLSM and simultaneous cell-ECM imaging. Diffusion through collagen-based hydrogels was affected by surface properties of the diffusive particles rather than a size exclusive filtering. Carboxylated mircospheres (Ø 20 nm) did not diffuse through the hydrogel pores; they showed a high binding affinity towards collagen fibres. Also after 72 h, a gradient from the outer hydrogel parts to the centre was observable. This small volume collagen-based hydrogel system allowed culture of 4 different cell lines, showing high cell viability and being suitable for short and long term cultures. Compared to 2D cultures, adherent cell lines showed a different morphology in 3D, while non-adherent K562 cells did not show a morphological change. Studies on COS7 cells showed that next to morphology also cytoskeleton organisation was a function of the local microenvironment. In contrast, no differences in the intracellular organelle organisation between cells cultured in 2D or 3D was observed. Additionally this small volume collagenbased hydrogel system was suitable for single molecule microscopy measurements using the lipid like tracer molecule CellMask™Orange; a specific probe for plasma membrane labelling without biological function. This model system, combined with confined HILO excitation and a customised algorithm allowed single molecule microscopy also in a more complex, 3D microenvironment. Overall it was shown that mimicking a more natural, bioengineered microenvironment in a realistic experimental model can deepen the understanding of cancer cell behaviour and reaction to anti-cancer treatment. Moreover a 3D microenvironment does not exclude quantitative molecular assessment using single molecule microscopy, but therefore model system and analysis methods had to be adapted to this more complex situation. |
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Alternatives oder übersetztes Abstract: |
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URN: | urn:nbn:de:tuda-tuprints-41816 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie | ||||
Fachbereich(e)/-gebiet(e): | 10 Fachbereich Biologie > Membrane Dynamics 10 Fachbereich Biologie |
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Hinterlegungsdatum: | 12 Okt 2014 19:55 | ||||
Letzte Änderung: | 12 Okt 2014 19:55 | ||||
PPN: | |||||
Referenten: | Meckel , PD Dr. Tobias ; Thiel, Prof. Dr. Gerhard | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 5 September 2014 | ||||
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