Influence of Tamoxifen on Different Biological Pathways in Tumorigenesis and Transformation in Adipose-Derived Stem Cells, Mammary Cells and Mammary Carcinoma Cell Lines : an In Vitro Study

Breast carcinoma is one of the most common malignant tumors in women. In cases of
hormone-sensitive cells, tamoxifen as an anti-estrogenic substance is a first line medication in the
adjuvant setting. The spectrum of autologous breast reconstructions ranges from fat infiltrations to
complex microsurgical procedures. The influence of adipose-derived stem cells (ASC) on the tumor
bed and a possibly increased recurrence rate as a result are critically discussed. In addition, there
is currently no conclusive recommendation regarding tamoxifen-treated patients and autologous
fat infiltrations. The aim of the present study was to investigate the effect of tamoxifen on the gene
expression of a variety of genes involved in tumorigenesis, cell growth and transformation. Mammary
epithelial cell line and mammary carcinoma cell lines were treated with tamoxifen in vitro as well
as co-cultured with ASC. Gene expression was quantified by PCR arrays and showed increased
expression in the mammary carcinoma cell lines with increasing time of treatment and concentration
of tamoxifen. The data presented can be considered as an addition to the controversial discussion on
the relationship between ASC and breast carcinoma cells. Further studies are needed to quantify the
in vivo interaction of ASC and mammary carcinoma cells and to conclusively assess the impact of
tamoxifen in reconstructive cases with fat grafting.