Activation and differentiation of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent cells and exhibit two main characteristics that define stem cells: self-renewal and differentiation. MSCs can migrate to sites of injury, inflammation, and tumor. Moreover, MSCs undergo myofibroblast-like differentiation, including increased production of alpha smooth muscle actin (α-SMA) in response to transforming growth factor-β (TGF-β), a growth factor commonly secreted by tumor cells to evade immune surveillance. Based on our previous finding, hMSCs become activated and resemble carcinoma-associated myofibroblasts upon prolonged exposure to conditioned medium from MDAMB231 human breast cancer cells. Here, we show that keratinocyte-conditioned medium (KCM) induces differentiation of MSCs to resemble dermal myofibroblast-like cells using immunofluorescence techniques demonstrating punctate vinculin staining, and F-actin filaments.