The bad and the good of mesenchymal stem cells in cancer: Boosters of tumor growth and vehicles for targeted delivery of anticancer agents

Figure 1 Diagram of mesenchymal stem cell hierarchy. At top of diagram are indicated the MAPCs that posses a higher proliferative and differentiative potential compared to classical MSCs. These may represent a more primitive subset of stem cells that could be the common precursor of MSCs, HSCs and EPCs. In the diagram are indicated the mesenchymal and non-mesenchymal cell types that originate from these different classes of stem cells. The dashed lines indicate putative differentiation pathways. MSCs: Mesenchymal stem cells; MAPCs: Multipotent adult progenitor cells; HSCs: Hematopoietic stem cells; EPCs: Endothelial progenitor cells.

Figure 2 MSCs may contribute to tumor growth in several ways: Promoting angiogenesis; Creating a niche to support cancer stem cells survival; Modulating the organism’s immune response against cancer cells; Promoting formation of metastasis.

Figure 3 Mesenchymal stem cells as vehicle for anticancer drug. In the Figure are indicated the vectors used to engineer MSCs and the “therapeutical genes”. Target cancer cells are in parenthesis. MSCs: Mesenchymal stem cells; IL12: Interleukin-12; IFN-γ: Interferon-gamma; TRAIL: Tumor necrosis (TNF)-related apoptosis-inducing ligand.