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.