Characterization of 5-HT transporter and receptor system in HeLaS3 cells by [3H]8-OH-DPAT and other serotonergic ligands

• Published in: Archives of biochemistry and biophysics 2011-02, Vol.506 (1), p.66-72
• Main Authors: Feng, Jin-Jye, Cheng, Fong-Chi, Lin, Chun-Hsiung, Wei, Jiann-Wu, Yang, Shiaw-Der
• Format: Article
• Language: English
• Subjects: 5-HT receptor subtypes; 5-HT transporters; 8-Hydroxy-2-(di-n-propylamino)tetralin - metabolism; [3H]8-OH-DPAT; binding sites; Binding, Competitive; Biogenic Amines - metabolism; carcinogenesis; Cocaine - analogs & derivatives; Cocaine - metabolism; dose response; drugs; Fluoxetine - metabolism; HeLa Cells; HeLaS3; Humans; Kinetics; Ligands; neoplasm cells; Paroxetine - metabolism; Radioligand Assay; Radioligand binding assay; receptors; Receptors, Serotonin - metabolism; serotonin; Serotonin Plasma Membrane Transport Proteins - metabolism; Serotonin Uptake Inhibitors - metabolism; transporters; tritium; Vesicular Biogenic Amine Transport Proteins - antagonists & inhibitors
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/j.abb.2010.10.024

▸ [3H]8-OH-DPAT not only binds to intact HeLaS3 cells with high specific binding. ▸ But also it has multiple binding sites, some of which relate to uptake. ▸ [125I]RTI-55 and [3H]paroxetine bound in a saturable fashion to HeLaS3 cells. ▸ One or more of the related to 5-HT receptor subtypes was manifested in HeLaS3 cells. ▸ Radioligand binding properties varied between membrane preparation and intact cell. [3H]8-OH-DPAT is a selective ligand for labeling 5-HT1A receptor sites. In competition binding experiments, we found that classic biogenic amine transporter inhibitors displaced [3H]8-OH-DPAT binding at its high-affinity binding sites in HeLaS3 cells. [125I]RTI-55 and [3H]paroxetine are known to specifically label amine transporter sites, and this was observed in our cells. Displacement studies showed that 8-OH-DPAT displayed affinity in a dose-dependent manner for the labeled amine transporter sites. These data suggest that [3H]8-OH-DPAT binds to amine uptake sites in HeLaS3 cells. A variety of drugs targeting different classes of receptors did not significantly affect [3H]8-OH-DPAT binding. Moreover, we determined the specific binding effects of various serotonergic ligands (i.e. [125I]cyanopindolol, [3H]ketanserin/[3H]mesulergine, [3H]GR-65630, [3H]GR-113808 and [3H]LSD) that specifically labeled 5-HT1, 5-HT2, 5-HT3, 5-HT4 and 5-HT5–7 receptors, respectively. It is suggested that HeLaS3 cells contain distinct types of the related to 5-HT receptor recognition binding sites. These observations could help elucidate the relevant characteristics of different types of 5-HT receptors and 5-HT membrane transporters in tumor cells and their role in tumorigenesis.