Mesenchymal Stem Cell-Mediated Effects of Tumor Support or Suppression

Abstract

Mesenchymal stem cells (MSCs) can exhibit a marked tropism towards site of tumors. Many studies have reported that tumor progression and metastasis increase by MSCs. In contrast, other studies have shown that MSCs suppress growth of tumors. MSCs contribute to tumor growth promotion by several mechanisms: (1) transition to tumor-associated fibroblasts; (2) suppression of immune response; (3) promotion of angiogenesis; (4) stimulation of epithelial-mesenchymal transition (EMT); (5) contribution to the tumor microenvironment; (6) inhibition of tumor cell apoptosis; and (7) promotion of tumor metastasis. In contrast to the tumor-promoting properties, MSCs inhibit tumor growth by increasing inflammatory infiltration, inhibiting angiogenesis, suppressing Wnt signaling and AKT signaling, and inducing cell cycle arrest and apoptosis. In this review, we will discuss potential mechanisms by which MSC mediates tumor support or suppression and then the possible tumor-specific therapeutic strategies using MSCs as delivery vehicles, based on their homing potential to tumors.

Keywords: delivery vehicles; homing; mesenchymal stem cells; tumor microenvironment.

Figure 1

Role of MSCs in tumor formation or suppression. MSCs can regulate transition to tumor-associated fibroblasts, immune response, angiogenesis, EMT, cancer stem cells, metastasis, and apoptosis. Alternatively, growing evidence shows that MSCs inhibit tumor cell function by inducing apoptosis, cell cycle arrest, and inflammatory infiltration and inhibiting the Wnt and AKT signaling pathways.