Lysophosphatidic acid is a naturally occurring lysophospholipid that activates diverse cellular actions in various cells including proliferation and morphological changes. There are currently three known genes that encode proteins of the LPA receptor family- Edg2, Edg4 and Edg7.

Lysophosphatidic acid receptor 1 (also known as Lpa1), encoded by Edg2, belongs to G-coupled protein receptor (GPCR) superfamily. All three proteins share 50-54% identical amino-acids. Lpa1 mostly activates the G_i pathway that leads to inhibition of adenylate cyclase and thus inhibition of cAMP production. Through this pathway, Lpa1 also initiates the Ras/MAP kinase cascade which is primarily responsible for increased cell proliferation¹. Interestingly, binding of lysophosphatidic acid to the G₁₃ G-protein activates the small GTP-binding protein Rho and induces the rapid remodeling of the actin cytoskeleton².

Lpa1 has been implicated in the pathogenesis of metastatic bone cancer. Silencing of Lpa1 expression in breast and ovarian cancer cells significantly alters the progression of bone metastasis through reduction of tumor burden and inhibition of bone resorption. A specific Lpa1 antagonist exhibits specificity for tumor cell-platelet interaction without abrogating normal platelet function³.