Role of GPCRs in cancer

G Protein-Coupled Receptors (GPCRs) comprise the largest family of receptors in mammalian cells, whose activity mediates a variety of neuronal and nonneuronal cellular functions. GPCRs have been implicated in a variety of diseases and recently they have been proposed as possible mediators in cancer development, for example, protease activated receptors that normally function in thrombin signaling but have been reported to increase cell proliferation and angiogenesis. Chemokine receptors function in immune cell motility, yet their activity appears to play a part in cancer metastasis to other organs. Metabotropic glutamate receptor 1 is an excitatory neuronal receptor whose aberrant expression in melanocytes correlates with cell transformation in vitro and spontaneous metastatic melanoma development in vivo. Frizzled receptors functioning in stem cell proliferation have been implicated in colon and liver cancer initiation and progression. Current drugs that target these receptors are being explored as potential alternatives/compliments to available cancer therapies to treat cancer. This chapter will review how the activities of different GPCRs participate in cancer initiation and progression, in addition to some therapeutic options that have been applied to target these receptors.