Multipotent Mesenchymal Stromal Cells - A Promising Cytotherapeutic Agent for Breast Cancer

Treating breast cancer has been quite a challenge due to drug resistance and the complexity of the tumor microenvironment. Moreover, the non-specificity of chemotherapeutic agents confers side effects while treating aggressive subtypes like triple-negative breast cancer. While targeted therapies are evolving, novel cellular therapies have a promising scope for treating breast cancer, as they can be tailored and allogeneic. Tailored cellular therapies face challenges such as cell availability and the cost of development as well as deployment. While allogeneic cellular therapies overcome these disadvantages, they face graft-versus-host disease. To overcome this, cells with no MHC-I and II, or less immunogenic cells with anti-cancer abilities, are attractive choices. One such cell type is the multipotent mesenchymal stromal cell (MSC). These cells are less immunogenic, have immunomodulatory properties, and are also known to home to tumor sites. Such properties can enable their exploitation for delivering drugs and other biotherapeutics. In addition, they seem to possess a natural tumor-inhibiting capability. However, it may be dependent on a multitude of factors, including cancer type, stage of presentation, and the tumor microenvironment. This review examines the fundamental biological mechanisms behind the anti-breast cancer effects of mesenchymal stem cells (MSCs), summarizes current advances in MSC-based therapeutic approaches for breast cancer, and explores the potential of genetically engineered MSCs in treatment, while identifying the existing research and application gaps.