Abstract
Finding out the driver gene critical for the maintenance of breast cancer stem cells (BrCSCs) is important for designing a new strategy to eradicate these cells to improve patient's prognosis. Here, in our study, we revealed that PIM1, an oncogenic serine-threonine kinase and a well-proven contributor to the tumorigenesis of breast cancer, was involved in BrCSCs regulation and promised to be a new target for eradicating BrCSCs. In brief, PIM1 could enhance the stem cell-like traits of breast cancer cells by promoting the phosphorylation and cytoplasmic localization of RUNX3. The nuclear dislocation of RUNX3 disabled this tumour suppressor and led to breast cancer cells gaining stem cell-like traits. Inhibition of PIM1 significantly induced the nuclear retention of RUNX3, recovered its transcriptional function and attenuated the stem cell-like properties of breast cancer cells. Those findings deepened our understanding of PIM1's oncogenic effect, underlining the significance of PIM1 in designing a new strategy aimed at BrCSCs.