Lysophosphatidic acid (LPA) receptor-mediated signaling and cellular responses to anticancer drugs and radiation of cancer cells

Lysophosphatidic acid (LPA) is a simple physiological lipid and structurally consists of a fatty, a phosphate and a glycerol. LPA binds to G protein-coupled LPA receptors (LPA1 to LPA6). LPA receptor-mediated signaling mediates a variety of biological responses, such as cell growth, migration, morphogenesis, differentiation and protection from apoptosis. It is considered that LPA receptor-mediated signaling plays an important role in the pathogenesis of human malignancies. So far, genetic and epigenetic alterations of LPA receptors have been found in several cancer cells as well as abnormal LPA production. In addition, LPA receptor-mediated signaling regulates the promotion of malignant behaviors, including chemo- and/or radiation-resistance. Chemotherapy and radiotherapy are the common approaches to the treatments of cancers. However, resistance to anticancer drugs and irradiation is the most critical limitation for chemotherapy and radiotherapy. In this review, we provide the roles of LPA receptor-mediated signaling in the regulation of cellular responses induced by chemotherapeutic agents and irradiation and its biological utility as a possible molecular target for improving cancer cell responses to chemotherapy and radiotherapy.