Abstract (eng)
Ovarian cancer is one of the most lethal malignancies among women. It is a disease with a generally unfavorable outcome due to late diagnosis, and late stage ovarian cancer has typically already started to metastasize. For advanced stage ovarian cancer, the usual care is surgery and platinum-based chemotherapy, whereby most patients experience a relapse of cancer, and a recurring ovarian cancer is not curable, which can be attributed to a developed chemoresistance. Based on current knowledge,
two well-known factors contribute significantly to the development of chemoresistance in ovarian cancer, namely hypoxia and shear stress. Hypoxia regulates many signaling pathways and thus cancer growth
and influences post-translational modifications of various proteins. Shear Stress impacts morphology, expression of biomarkers, and aggressiveness of tumor cells, providing an ideal tumor microenvironment. Both hypoxia and shear stress are though to affect mitochondrial morphology and
protein composition of the electron transport chain Within this thesis, two human ovarian cancer cell lines (SKOV-3 and OVCAR-3) were subjected to the oxygen level (hypoxia) or the biophysical stimulation (shear stress) of an ovarian cancer environment to mimic the in vivo situation more accurately. Cells were microscopically monitored and imaged prior and after the respective treatments, to subsequently evaluate the morphological alterations with respect to area, perimeter, major and minor axes, circularity, and roundness of the cells. Furthermore, proteomic alterations were determined using mass spectrometric analysis (cell lysis, proteolytic digestion, and LC-MS/MS), and finally, regulated proteins and thus the affected signaling pathways were identified by bioinformatic analysis. Depending on the proteomic analysis (untargeted proteomic or phosphoproteome analysis), cells were treated for 24 h (long-term) or 3 h (short-term), respectively.
For both cell lines, morphological as well as proteomic alterations could be determined after 24 h treatment in the respective experimental condition, with identified proteins consistent with and exceeding those reported in literature. Based on the 3 h incubations, the different treatment groups (hypoxic, shear stress, and normoxic static control) could only be vaguely separated from each other via PCA, and almost no regulated proteins could be identified in the basic proteomic profiles of both cell lines. An exhaustive molecular interpretation and discussion of the proteomics data is beyond the scope of this master’s thesis, as the aim was to create a suitable experimental design and to gain first insights into the impacts of artificial hypoxia and fluid shear stress using the respective methods on ovarian cancer cell lines. In conclusion, we identified significant morphological and proteomic (untargeted as well as phospho-proteomic) alterations for both cells lines after both treatments compared to the control cells, suggesting the methods are suitable for mimicking the ovarian cancer microenvironment more adequately.