Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Balic, M.
Disseminating breast cancer stem cells and their molecular characterization
[ Dissertation ] Medical University of Graz; 2013. pp. 76
[OPEN ACCESS]
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- Autor*innen der Med Uni Graz:
- Balic Marija
- Betreuer*innen:
- Samonigg Hellmut
- Speicher Michael
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- Abstract:
- The cancer stem cell model hypothesizes the existence of a small proportion of tumor cells capa-ble to sustain tumor formation, self-renewal and differentiation. In breast cancer, these cells were associated with CD44+CD24-low and aldehydedehydrogenase positive phenotype. While the possi-ble presence of early tumor dissemination and micrometastases is the rationale behind the use of systemic adjuvant treatment in patients who have undergone definitive surgery of the primary tumor [1, 2], the presence of cancer stem cells (CSC) may explain the failure of adjuvant chemo-therapy in a proportion of early stage breast cancer patients. In this master thesis the suitability of current approaches for breast cancer stem cell analyses to evaluate heterogeneity of breast can-cer cells through their extensive molecular characterization was investigated. Furthermore, ap-proaches for evaluation of disseminating tumor cells, and their association with CSC were opti-mized. First, the breast cancer cell lines MCF7 and SUM159 were cultured in adherent conditions and as mammospheres. Flow cytometric sorting for breast cancer stem cell markers was performed. Sorted and unsorted populations, mammospheres and adherent cell cultures were subjected to DNA profiling by array-CGH and methylation profiling. Further, methods for analyses of dissemi-nating breast CSC were optimized, including CTC microchip enrichment and analyses of on chip DNA profiling. Array CGH did not reveal any genomic differences and there is evidence that epigenetic differ-ences cannot in cell lines are indecisve. After CTC microchip optimization sufficient sensitivity was reproduced, and can be further used as method for evaluation of peripheral blood of breast can-cer patients for CTC and putative breast cancer stem cell markers. Established breast cancer stem cell models in breast cancer cell lines may not be suitable to de-fine molecular heterogeneity of breast CSC. The percentage of breast CSC in the enriched fraction remains unknown. This work underscores requirement of additional approaches to reveal intra-tumoral heterogeneity of breast cancer and disseminating cells and their association with breast CSC.