Discovery and characterization of [ 3H]8-OH-DPAT binding to HeLaS3 cells

• Published in: Archives of biochemistry and biophysics 2010-03, Vol.495 (1), p.14-20
• Main Authors: Feng, Jin-Jye, Cheng, Fong-Chi, Lin, Chun-Hsiung, Wei, Jiann-Wu, Yang, Shiaw-Der
• Format: Article
• Language: English
• Subjects: 5-HT 1A receptor; 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; [ 3H]8-OH-DPAT; Binding, Competitive; Dimethyl Sulfoxide - metabolism; GPCRs; HeLa Cells; HeLaS3; Humans; Radioligand Assay; Radioligand binding assay; Receptor, Serotonin, 5-HT1A - metabolism; Receptors, G-Protein-Coupled - metabolism; Serotonin Receptor Agonists - pharmacology
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/j.abb.2009.12.012

Some G protein-coupled receptors (GPCRs) have functional links to cancer biology, yet the manifestation of GPCRs in tumor types is little studied to date. Using a battery of radioligand binding assays, we sought to characterize GPCR recognition binding sites on HeLaS3 tumor cells. High levels of binding of the selective serotonin 5-HT 1A receptor agonist [ 3H]8-OH-DPAT were observed in these cells. Saturation and homologous competition experiments indicated that [ 3H]8-OH-DPAT bound different populations of high- and low-affinity sites. In competition experiments, several serotonergic compounds displaced [ 3H]8-OH-DPAT binding with low potency from its high-affinity binding sites, suggesting that low-affinity binding is the predominant mode of binding. A variety of drugs targeting different classes of receptors did not affect [ 3H]8-OH-DPAT binding. These observations may help elucidate the pathophysiological and functional relevance of 5-HT receptors in tumor cells and link GPCRs and tumorigenic mechanisms to pharmacological and chemotherapeutic paradigms.