Lysophospholipid Signalling and the Tumour Microenvironment

Homeostasis is the key to survival. This is as true for the tumour cell as it is for the normal host cell. Tumour cells and normal host cells constantly interact with each other, and the balance of these interactions results in the prevailing homeostatic conditions. The interactions between the milieu of signalling molecules and their effects on the host and tumour cells are known as the tumour microenvironment. The predominant balance of effects within the tumour microenvironment will determine if the tumour cells can evade the host's responses to survive and grow or if the tumour cells will be eradicated. Lysophospholipids (LPLs) are a group of lipid signalling molecules which exert their effects via autocrinic and paracrinic mechanisms. Therefore, LPLs are being explored to determine if they are potentially key signalling molecules within the tumour microenvironment. The effects of LPLs within the tumour microenvironment include modulating cell proliferation, cell survival, cell motility, angiogenesis and the immune system. These are all important activities that affect the balance of host-tumour cell interactions. This chapter expands on these functions and also the role that LPLs could play as a potential treatment target in the future.