Role of the RAB27/SYTL Axis in Tumor Microenvironment Construction.

Crosstalk between cancer cells and the tumor microenvironment (TME) is a key event in malignant progression and metastasis. The secretion of bioactive substances by cancer cells remodels the TME, affecting the activities of its components, including blood vessels, mesenchymal cells, and immune cells. These substances are effectively delivered through intracellular trafficking and exocytosis of cytoplasmic vesicles. The small guanosine triphosphatase (GTPase) RAB27 and its effectors, synaptotagmin-like (SYTL) family proteins, play essential roles in vesicle trafficking. Our recent research demonstrates the upregulation of RAB27A/B and SYTL1/2 in alveolar soft part sarcoma and acute myeloid leukemia. This enhanced trafficking promotes angiogenesis and the occupation of leukemia cells in the bone marrow niche. This review focuses on the role of the RAB27/SYTL axis in various cancer types associated with TME modifications, with a discussion on its importance as a therapeutic target.