Fig. 1.

Emerging areas for mesenchymal stem cells (MSCs) in bone metastasis. 1) MSCs can maintain dormancy in breast cancer cells via TGFβ2 and BMP7, but also induce proliferation of dormant cancer cells via N-cadherin. 2) Cancer cells rewire metabolism of MSCs and other stromal cells, impairing normal hematopoiesis while facilitating cancer cell survival, proliferation, and chemoresistance via transfer of reactive oxygen species (ROS), organelles, and amino acids such as glutamine. 3) Age-related changes in MSCs have profound effects on cancer progression by increased senescence, secretion of senescence associated secretory phenotypes (SASP) factors, and increased bone marrow adipocytes. 4) Immunomodulatory roles of MSCs include inhibitory effects via adhesion molecules and release of TGFβ and HGF, but engineering MSCs to deliver cargo, such as IL-7 and IL-12, offers improved efficacy of CAR-T cells. Figure created with BioRender.com.