The Role of Mesenchymal Stem Cells in the Tumor Microenvironment

Abstract

Currently, there are many promising clinical trials using mesenchymal stem cells (MSCs) in cell-based therapies of diseases ranging widely from graft-versus-host to joint and cartilage disorders (Salem and Thiemermann 2010; Tolar, Le Blanc et al.). Increasingly, however, there is a concern over the clinical use of MSCs because they are also known to home to tumors and once resident in the tumor microenvironment (TME) to support tumor growth and spread (Karnoub, Dash et al. 2007; Kidd, Spaeth et al. 2008; Coffelt, Marini et al. 2009; Klopp, Gupta et al. 2010; Klopp, Gupta et al. 2011). Conversely, other studies have reported that MSCs found in the TME diminish tumor growth, which has further generated some controversy in this field (reviewed in (Klopp, Gupta et al. 2010; Klopp, Gupta et al. 2011). Either way as a result of the MSC propensity for the TME, genetically modified MSCs that can act as “Trojan horses” and deliver anti-cancer therapeutics into the tumor stroma are being evaluated as a promising new specific cell-based therapy for cancer.