Adipose‑derived mesenchymal stem cells exhibit tumor tropism and promote tumorsphere formation of breast cancer cells.

Mesenchymal stem cells reportedly have a marked effect on tumor growth or suppression. However, it remains uncertain whether adipose‑derived mesenchymal stem cells (ADSCs) from grafted fat can contribute to breast cancer growth and recurrence. In the present study, interactions between ADSCs and MCF‑7 breast cancer cells were evaluated in a Matrigel co‑culture system and in an in vivo nude mouse model. Results suggested that MCF‑7 cells exerted tumor tropism effects on ADSCs and this may be regulated by chemokines, such as the macrophage inflammatory protein (MIP)‑1δ and MIP‑3α. Additionally, ADSCs significantly induced tumorsphere formation in vitro and promoted tumorigenicity in vivo. RT‑qPCR analysis indicated that tumorsphere formation by MCF‑7 cells was associated with the induction of stem‑like properties, which was mediated by epithelial‑-mesenchymal transition. Together, the present findings indicated that ADSCs exhibit tropism and induce tumorsphere formation of MCF‑7 cells.