Secretome within the bone marrow microenvironment: A basis for mesenchymal stem cell treatment and role in cancer dormancy.

The secretome produced by cells within the bone marrow is significant to homeostasis. The bone marrow, a well-studied organ, has multiple niches with distinct roles for supporting stem cell functions. Thus, an understanding of mediators involved in the regulation of stem cells could serve as a model for clinical problems and solutions such as tissue repair and regeneration. The exosome secretome of bone marrow stem cells is a developing area of research with respect to the regenerative potential by bone marrow cell, particularly the mesenchymal stem cells. The bone marrow niche regulates endogenous processes such as hematopoiesis but could also support the survival of tumors such as facilitating the cancer stem cells to exist in dormancy for decades. The bone marrow-derived secretome will be critical to future development of therapeutic strategies for oncologic diseases, in addition to regenerative medicine. This article discusses the importance for parallel studies to determine how the same secretome may compromise safety during the use of stem cells in regenerative medicine.

Immune modulation by a cellular network of mesenchymal stem cells and breast cancer cell subsets: Implication for cancer therapy.

The immune modulatory properties of mesenchymal stem cells (MSCs) are mostly controlled by the particular microenvironment. Cancer stem cells (CSCs), which can initiate a clinical tumor, have been the subject of intense research. This review article discusses investigative studies of the roles of MSCs on cancer biology including on CSCs, and the potential as drug delivery to tumors. An understanding of how MSCs behave in the tumor microenvironment to facilitate the survival of tumor cells would be crucial to identify drug targets. More importantly, since CSCs survive for decades in dormancy for later resurgence, studies are presented to show how MSCs could be involved in maintaining dormancy. Although the mechanism by which CSCs survive is complex, this article focus on the cellular involvement of MSCs with regard to immune responses. We discuss the immunomodulatory mechanisms of MSC-CSC interaction in the context of therapeutic outcomes in oncology. We also discuss immunotherapy as a potential to circumventing this immune modulation.