Gene expression profiles of different breast cancer cells compared with their responsiveness to fermented mistletoe (Viscum album L.) extracts Iscador from oak (Quercus), pine (Pinus), white fir (Abies) and apple tree (Malus) in vitro.

Cytotoxicity assays in vitro (MTT test) showed that the different breast cancer cell lines Kpl-1, MCF-7 and Mfm-223 respond differently to the mistletoe (Viscum album L.) preparations Iscador. Quercus (Qu), Abies (A), Malus (M) and Pinus (P). In order to determine the differences in the responsiveness of the cells more exactly, the gene expression profiles were determined by cells, which were treated with Mistletoe extracts, compared with untreated control cells. Such differences can be analysed in more detail by looking at the gene expression using Human Whole Genome microarray chips (41,000 genes). The results of the transcriptome analyses suggested that Iscador preparations influenced the overregulation of genes regarding immune defense, stress response, apoptosis and cell-cell adhesion pathways. Within the Mfm-223-Zellen was the Genexpression in MCF-7 and Kpl-1. The MCF-7 cells were affected on the genes which are involved in cell-cell contacts whereas Kpl-1 responded to the mistletoe extracts by changing the mRNA levels of the immune and stress response pathways. Concerning the effects of the mistletoe extract, we conclude that Iscador Qu and M have a greater influence on the immune defense and stress response genes whereas Iscador A tends to affect the cell-cell adhesion and cytoskeleton pathways. In summary, cDNA microarray analyses give us information on whether a cancer cell is sensitive to mistletoe extracts in relation to how many genes are significantly overrepresented after mistletoe treatment, and whether a particular mistletoe extract is more effective on a specific cancer cell than the other preparation.