Introduction: Drug delivery to solid tumors remains a significant therapeutic challenge. Mesenchymal stem/stromal cells (MSCs) home to tumor tissues and can be employed as tumor targeted drug/gene delivery vehicles. Reportedly, therapeutic gene- or anti-cancer drug-loaded MSCs have shown remarkable anti-tumor effects in preclinical studies, and some clinical trials for assessing therapeutic MSCs in patients with cancer have been registered.
Areas covered: In the present review, we first discuss the source and interdonor heterogeneity of MSCs, their tumor-homing mechanism, and the route of MSC administration in MSC-based cancer therapy. We then summarize the therapeutic applications of MSCs as a drug delivery vehicle for therapeutic genes or anti-cancer drugs and the drug delivery mechanism from drug-loaded MSCs to cancer cells.
Expert opinion: Although numerous preclinical studies have revealed significant anti-tumor effects, several clinical trials assessing MSC-based cancer gene therapy have failed to demonstrate corroborative results, documenting limited therapeutic effects. Notably, a successful clinical outcome with MSC-based cancer therapy would require the interdonor heterogeneity of administered MSCs to be resolved, along with improved tumor-homing efficiency and optimized drug delivery efficiency from MSCs to cancer cells.
Keywords: Anti-cancer drug; cancer therapy; cell engineering; cell-based drug delivery; mesenchymal stem/stromal cells; targeting; tumor homing.