Background
Carcinoid tumors are associated with the carcinoid syndrome, a set of symptoms resulting from the peptide and amine products, including serotonin, secreted from the cancer cells. The
Conclusion
By inhibiting signaling through Akt, PTEN indirectly promotes serotonin synthesis and secretion.
Methods
PTEN was inhibited by pharmacological and molecular approaches, and the resultant secretion of serotonin and expression of tryptophan hydroxylase 1 (TPH1), the rate-limiting enzyme in serotonin synthesis, was assessed.
Results
Inhibition of PTEN in vitro, with concomitant increased Akt signaling, resulted in decreased secretion of serotonin, as well as decreased serotonin synthesis, as confirmed by reduced expression of TPH1. Inhibition of PTEN in BON cells in an animal model resulted in decreased serum serotonin.