Paracrine effects of stem cells in wound healing and cancer progression (Review)

Stem cells play an important role in tissue repair and cancer development. The capacity to self-renew and to differentiate to specialized cells allows tissue-specific stem cells to rebuild damaged tissue and cancer stem cells to initiate and promote cancer. Mesenchymal stem cells, attracted to wounds and cancer, facilitate wound healing and support cancer progression primarily by secreting bioactive factors. There is now growing evidence that, like mesenchymal stem cells, also tissue-specific and cancer stem cells manipulate their environment by paracrine actions. Soluble factors and microvesicles released by these stem cells have been shown to protect recipient cells from apoptosis and to stimulate neovascularization. These paracrine mechanisms may allow stem cells to orchestrate wound healing and cancer progression. Hence, understanding these stem cell-driven paracrine effects may help to improve tissue regeneration and cancer treatment.