Muscarinic receptors and cancer: possible implication in tumor of the nervous system.

Muscarinic receptors are expressed in several primary and metastatic tumours. In some of these, acetylcholine synthesized by the tumour cells through autocrine mechanism often mediated by muscarinic receptors, can contribute to tumour progression, modulating cell proliferation, survival, migration and angiogenesis. Acetylcholine also appears to be involved in brain tumours. In fact, patients with these pathologies show altered levels of ACh in their cerebrospinal fluid. Astrocytomas, glioblastomas and neuroblastomas express both nicotinic and muscarinic receptors, and their activation enhances different signal transduction pathways involving AKT, PIK3, MAPK and ERK. The present review is focused on recent studies demonstrating the muscarinic receptor involvement in the modulation of proliferation, survival and migration in tumours of the central and peripheral nervous system. These data together with observations reported for other pathologies, open up new interesting therapeutic perspectives for ACh and its receptors.