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Re-establishing pluripotency in adult cells derived from breast stromal tissue.

227 Background: Recent advances in pluripotent stem cell biology offer patient-specific disease models to investigate in vitro mechanisms of tumorigenesis. Induced pluripotent stem (iPS) cells were originally derived by reprogramming of human dermal fibroblasts through ectopic expression of pluripotency-associated transcription factors. A limitation to the use of dermal fibroblasts as the starting cell type for reprogramming is that it usually takes weeks to expand cells from a single biopsy, and the efficiency of the process is very low. In contrast, a large number of adipose-derived mesenchymal stromal cells (Ad-MSCs) can be easily obtained from the stroma of human breast tissue, without the time-consuming steps of cell expansion. Here we investigated the ability to induce pluripotency in committed, Ad-MSCs derived from the stroma of breast tissue.


METHODS
The aim of this study is to investigate the potential of using Ad-MSCs derived from surgically discarded breast stromal tissue to generate human iPS. Discarded tissue during surgical procedures was processed in vitro and Ad-MSCs were derived. These Ad-MSCs were then used to generate iPS cells by ectopic expression of "Yamanaka's cocktail" containing OCT4, SOX2, KLF4 and c-MYC.


RESULTS
The success rate in generating iPS cells from human Ad-MSCs derived from breast stromal tissue is very high compared to the use of dermal fibroblasts. In our study, almost all human Ad-MSC cell lines can be reprogrammed into iPS cells, which share the same characteristics as skin fibroblast-derived iPS cells and human embryonic stem cells in their morphology, gene expression profile and differentiation capacities.


CONCLUSIONS
We are now optimizing this approach and making it more clinically relevant by adopting an integration-free method to deliver the reprogramming factors. The successful reprogramming of breast stromal-derived Ad-MSCs into iPS cells may provide a valuable source of patient-specific iPS cells to study the mechanism of tumorigenesis in patients with breast cancer.