OCT4 Expression Enhances Features of Cancer Stem Cells in a Mouse Model of Breast Cancer

The cancer stem cell (CSC) hypothesis proposes that CSCs are responsible for metastasis and disease recurrence. Therefore, targeting CSCs has the potential to significantly improve outcomes for cancer patients. The OCT4 transcription factor gene is a master gene that plays a key role in the self-renewal and pluripotency of stem cells. In this study, we introduced an OCT4 reporting vector into 4T1 mouse breast cancer cells and sorted OCT4 high and OCT4 low cell populations. We then determined whether OCT4 expression is associated with maintenance and expansion of CSCs. We found that OCT4(high) 4T1 cells have an increased ability to form tumorsphere and a high expression of stem cell markers such as Sca-1, CD133, CD34, and ALDH1, when compared with OCT4(low) 4T1 cells. In addition, OCT4(high) 4T1 cells have greater tumorigenic potential in vivo. These findings suggest that OCT4 expression may be a useful target for stem cell-specific cancer therapy.