Biological and molecular characterization of a rat mammary cancer stem cell: an in vitro model

The current studies on cancer focus mainly in the research and the analysis of cancer stem cells. In our laboratory we obtained a pure rat breast cancer cell line, named LA7, derived from RAMA 25 cell line, that was generated by DMBA induced ductal adenocarcinoma (Dulbecco et al., 1978). LA7 cells spontaneously differentiate into luminal hemispherical structures, called domes that recapitulate in vivo alveologenesis. The aim of my study is to characterize LA7 cells in order to assess their stem cell-like properties, using different methodologies. I developed protocols to differentiate LA7 cells in three dimensional systems and I defined how to propagate LA7 cells in suspension culture, in form of mammospheres (LA7MM), for several passages, and I demonstrate their ability to differentiate into all cell lineages of the mammary gland. I demonstrated that LA7 cells may form functional hollow tubuli, that remind branched structures present in vivo, and expressing markers for luminal and myoepithelial lineages. I also showed that LA7 cells embedded in matrigel form cysts. I analyzed putative stem and cancer stem cells markers, in order to define a molecular characterization of LA7 cells. I analyzed LA7 tumor initiating ability in vivo in NOD-SCID mice, assessing that a single LA7 cell forms a differentiated tumor. The assessement of LA7 cell line and his biological and molecular analysis will provide a great model for further studies on cancer stem cell.