Functional Characterization of Cholinergic Receptors in Melanoma Cells

Simple Summary Interest in the involvement of the cholinergic system at the non-neuronal level emerged in recent years, thereby allowing to identify different physiological and pathological processes that acetylcholine and its receptors modulate in different tissues. The cholinergic system can also take part in the activation and maintenance of pathological processes such as neurodegenerative diseases and cancer. This review summarizes studies concerning the involvement of the cholinergic system in different tumor isotypes, with a special focus on melanoma, the most lethal form of skin cancer. In the last two decades, the scientific community has come to terms with the importance of non-neural acetylcholine in light of its multiple biological and pathological functions within and outside the nervous system. Apart from its well-known physiological role both in the central and peripheral nervous systems, in the autonomic nervous system, and in the neuromuscular junction, the expression of the acetylcholine receptors has been detected in different peripheral organs. This evidence has contributed to highlight new roles for acetylcholine in various biological processes, (e.g., cell viability, proliferation, differentiation, migration, secretion). In addition, growing evidence in recent years has also demonstrated new roles for acetylcholine and its receptors in cancer, where they are involved in the modulation of cell proliferation, apoptosis, angiogenesis, and epithelial mesenchymal transition. In this review, we describe the functional characterization of acetylcholine receptors in different tumor types, placing attention on melanoma. The latest set of data accessible through literature, albeit limited, highlights how cholinergic receptors both of muscarinic and nicotinic type can play a relevant role in the migratory processes of melanoma cells, suggesting their possible involvement in invasion and metastasis.