Effect of radiation and co-culture with fibroblasts on growth characteristics and invasiveness of 3D breast cancer models

Mei, Jia (2022): Effect of radiation and co-culture with fibroblasts on growth characteristics and invasiveness of 3D breast cancer models. Dissertation, LMU München: Fakultät für Biologie

Abstract

Invasiveness is a major factor contributing to cancer metastasis. Given the broad variety and plasticity of invasion mechanisms, assessing potential metastasis-promoting effects of irradiation for specific mechanisms is important for further understanding of potential adverse effects of radiotherapy. Previous investigations of radiation effects on invasion were mainly done by 2D methods that cannot differentiate different invasion mechanisms. In fibroblasts-led collective invasion mechanisms, fibroblasts degrade the extracellular matrix and produce tracks for cancer cells with epithelial traits to follow. A major goal of the present work was to establish a model for this invasion mechanism and to study the effect of radiation on it. After verifying their epithelial-like, non-invasive characteristics, breast cancer cells (MCF-7 and BT474) were co-cultured in ultra-low adhesion plates with human normal fibroblasts (BJ1-hTert and HDF). Cocultivation with fibroblasts had little effects on spheroid growth, radiation-induced growth delay and repair of DNA damage. Epithelial-like MCF-7 and BT474 cells gain ability to invade into matrix if cocultured with normal fibroblasts. High-resolution imaging showed features of fibroblast-led collective invasion. This new model was used to investigate radiation effects on invasiveness. Irradiation reduced the number of invading cells in models using BJ1-hTert, but not HDF. However, sensitivity to the radiomimetic drug neocarcinostatin was comparable in both fibroblast strains. Radiation had little effects on invasion distance, showing that with this model effects on number of invading cells and distance can be uncoupled. In conclusion, no invasion-promoting effect of irradiation could be found with this model. In proof-of-concept studies, analysis of NAD(P)H and FAD autofluorescence via TPEF and FLIM was tested as tool for label-free differentiation of cancer cells and fibroblasts in 3D situations, including invasion experiments. In addition, preliminary FLIM data suggest that MCF-7 cells undergo a transient metabolic shift towards oxidative phosphorylation after irradiation, which could be verified by mitochondrial staining experiments.

Abstract

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: 3D breast cancer models, Invasiveness, radiation effects
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
• Fakultäten: Fakultät für Biologie
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 28. November 2022
• 1. Bericht­erstatter:in: Friedl, Anna