The Role of 5-HT1A Receptor in the Cancer as a New Opportunity in Medicinal Chemistry

The 5-HT1A receptor is a pharmacologically well characterized serotonin receptor subtype and it has long been investigated because of its involvement in several physio-pathological mechanisms and treatment of neurological diseases like ansia and depression. Serotonin (5-HT) also shows many non-neural functions such as essential hypertension, embryogenesis, follicle maturation and behavior. Moreover it exerts a growth factor function on different types of non-tumoral cells, and it was also found to be related to oncogenes. In fact, growth-stimulatory activity of serotonin in different human tumor cells has been reported. Recently, new chemical molecules binding the 5-HT1A receptor have been described as novel therapeutic entities useful in neuroprotection, cognitive impairment, Parkinson's Disease, pain treatment, malignant carcinoid syndrome and cancer. It was widely demonstrated that 5-HT1A receptor is involved in the carcinogenesis and consequently in many human tumor types, such as prostate, bladder, small cell lung, colonrectal and cholangiocarcinoma. Furthermore depending on the tumor type, 5-HT1A receptor antagonists were shown to be able to block the 5HT-induced increase in tumor growth. In this review we have focused our attention on each tumor type where the 5-HT1A receptor is involved, investigating the role of this molecular target and the different classes of compounds that have shown the capability to modulate it. The analyzed aspects could represent the hint for the medical chemists to develop novel molecules as selective 5-HT1A agents useful to further elucidate the role this therapeutic target.