Developmental potency of human ES cell-derived mesenchymal stem cells revealed in mouse embryos following blastocyst injection

Pluripotent stem cell-derived mesenchymal stem cells for therapeutic applications, developmental study, and cancer research

Human mesenchymal stem cells (MSCs) have been widely studied and applied for the treatment of various diseases due to their crucial role in tissue repair and regeneration. Compared to MSCs isolated from somatic tissues, MSCs differentiated from human pluripotent stem cells (ps-MSCs) have demonstrated similar therapeutic effects while possessing some advantages in quality control and assurance, given their unlimited and consistent supply of source cells. This makes ps-MSCs highly druggable and promising for therapeutic applications. In this minireview, we introduce the latest progress in ps-MSC research, focusing on the therapeutic properties, origin, in vivo development, and application of ps-MSCs in cancer research. We will also discuss the perspectives and challenges of this relatively new source of MSCs.

Mesenchymal Stromal Cells Increase the Natural Killer Resistance of Circulating Tumor Cells via Intercellular Signaling of cGAS-STING-IFNβ-HLA

Circulating tumor cells (CTCs) shed from primary tumors must overcome the cytotoxicity of immune cells, particularly natural killer (NK) cells, to cause metastasis. The tumor microenvironment (TME) protects tumor cells from the cytotoxicity of immune cells, which is partially executed by cancer-associated mesenchymal stromal cells (MSCs). However, the mechanisms by which MSCs influence the NK resistance of CTCs remain poorly understood. This study demonstrates that MSCs enhance the NK resistance of cancer cells in a gap junction-dependent manner, thereby promoting the survival and metastatic seeding of CTCs in immunocompromised mice. Tumor cells crosstalk with MSCs through an intercellular cGAS-cGAMP-STING signaling loop, leading to increased production of interferon-β (IFNβ) by MSCs. IFNβ reversely enhances the type I IFN (IFN-I) signaling in tumor cells and hence the expression of human leukocyte antigen class I (HLA-I) on the cell surface, protecting the tumor cells from NK cytotoxicity. Disruption of this loop reverses NK sensitivity in tumor cells and decreases tumor metastasis. Moreover, there are positive correlations between IFN-I signaling, HLA-I expression, and NK tolerance in human tumor samples. Thus, the NK-resistant signaling loop between tumor cells and MSCs may serve as a novel therapeutic target.