G protein-coupled receptors in cancer stem cells

G protein-coupled receptors (GPCRs) are highly expressed on a variety of tumour tissues while several GPCR exogenous ligands become marketed pharmaceuticals since they can target GPCRs to modulate plenty of cancer cell functions. In recent decades, cancer stem cells (CSCs) become widely investigated drug targets for cancer therapy but its underlying mechanism is still not fully elucidated. There are vigorous participations of GPCRs in CSCs-related signalling and functions, such as biomarkers for CSCs, essential receptors for activating Wnt, Hedgehog (HH) and other signalling pathways to facilitate CSCs progressions. This relationship can not only uncover a novel molecular mechanism for GPCR-mediated cancer cell functions but also assist our understanding in maintaining and modulating CSCs. Moreover, GPCR antagonists and monoclonal antibodies could be applied to impair CSCs functions and consequently attenuate tumour growth, which are anticipated to turn into marketed anticancer drugs via monotherapy or combination therapy with validated chemicals after clinical studies. Therefore, this review summarizes and provides sufficient evidences on regulation of GPCR signalling in the maintenance, differentiation and pluripotency of CSCs, linking GPCRs with CSCs, and suggesting targeting GPCRs on the surface of CSCs as potential therapeutic strategies for cancer therapy.