Regulation of Tumor Immune Microenvironment by Sphingolipids and Lysophosphatidic Acid

The tumor microenvironment (TME) consists of cancer cells that interact with stromal components such as the extracellular matrix, blood, and lymphatic networks, fibroblasts, adipocytes, and the cells of the immune system. Further, the tumor immune microenvironment, majorly represented by the tumor-infiltrating immune cells (TIIC), plays an important role in cancer therapeutics and patient prognosis. In fact, a high density of TIICs within the tumor microenvironment is known to be associated with better outcomes in several types of cancers. Towards this, two bioactive lipid molecules, lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), regulate the homing of immune cells to the TME. In the present review, we will uncover the role of LPA and S1P signaling in the tumor immune environment, highlighting the latest progress in this field.