Mesenchymal stem cells derived from bone marrow favor tumor cell growth in vivo

Controversial issue: Is it safe to employ mesenchymal stem cells in cell-based therapies?

“…There is also evidence that MSC, when injected subcutaneously together with tumor cells, can increase tumor growth by increasing the rates of tumor necrosis and angiogenesis (Zhu et al, 2006). In a breast cancer xenograft model, though having no effect on tumor growth per se, MSC greatly increased the metastasis rate through secretion of CCL5 (also called RANTES) (Karnoub et al, 2007).…”

Extracellular acidity strengthens mesenchymal stem cells to promote melanoma progression

“…4 Role of MSC in modulating cancer progression is still under debate, with some indications suggesting antitumor activity, 5,6 and some others showing promoting activity. 4,[7][8][9] MSC, whether mixed with low metastatic breast cancer cells, induce an increased metastatic dissemination through a paracrine manner elicited by the CCL5 chemokine-CCR5 receptor interactions 9 or interleukin 17B/IL-17B receptor signaling. 4 MSC also trigger in human colorectal cancer cells an increased invasiveness, which requires a cell-to-cell contact mediated by TGFb.…”

Mesenchymal stem cells inhibit proliferation and apoptosis of tumor cells: impact on in vivo tumor growth

“…10,11 Although some studies have observed that these cells inhibit tumor growth in murine 12 and rat 13,14 models, others have demonstrated an opposite effect. 15,16 Depending on the system used, MSC have been shown to favor tumor growth either by promoting their invasive abilities via the activation of matrix metalloproteinases 15 and neoangiogenesis 16 or by preventing tumor cells recognition by the immune system. 17 Regardless of the effect on tumor growth and progression, most studies have documented a selective migration of MSC to the tumor site and this property has been successfully exploited in animal models to deliver therapeutic molecules using MSC transduced with specific genes.…”