title: Retinoic acid receptor in subclone of human salivary gland adenocarcinoma cell line HSG and effect of retinoic acid on cellular growth.
abstract: Retinoic acid (RA) binding has been detected in the nuclei of a subclone (CL-1) of human submandibular adenocarcinoma cell line HSG conditioned to grow in a serum-free defined medium. Competition assay confirmed the specificity of the RA binding. Scatchard analysis showed the binding molecule to have a high affinity and low capacity. From the analyses by gel-filtration and glycerol density gradient centrifugation, the nuclear binding molecule appears to be distinct from cellular RA binding protein (CRABP) in terms of molecular weight. Furthermore, immunoblotting analysis revealed a band (Mr 47,000) reactive with specific antibody to RA receptor (RAR) alpha in the gel containing the nuclear fraction of CL-1 cells. Northern blotting analysis with specific cDNA probes revealed the expression of RAR alpha and RAR gamma in CL-1 cells. These results indicate that CL-1 cells express two types of RAR subtype, suggesting that these receptor molecules may mediate biological effects of RA. Treatment of CL-1 cells with RA resulted in an increase in the incorporation of [3H]thymidine into TCA-insoluble materials. The maximal increase was observed at 10(-6) M around 48 h. Previously, we demonstrated the autocrine growth of HSG cells mediated by epidermal growth factor (EGF) receptors and EGF-like molecules (Kurokawa et al. (1989) Cancer Res. 49, 5136-5142) and showed that RA had no significant effect on the secretion of the EGF-like molecule. RA induced an increase in [125I]EGF binding to CL-1 cells. The increase in the EGF binding was maximal at 24 h at 10(-6) M RA. RA also increased the amount of [3H]leucine-labeled EGF receptor dose-dependently. No significant change was observed in total protein synthesis of CL-1 cells by treatment with RA. These results suggest that RA stimulates the growth of CL-1 cells by increasing EGF receptor levels.
authors.affiliation: Department of Biochemistry, Iwate Medical University School of Dentistry, Morioka, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kurokawa
authors.forename: S
authors.initials: S
authors.lastname: Kyakumoto
authors.forename: M
authors.initials: M
authors.lastname: Ota
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D002999:Clone Cells; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018168:Receptors, Retinoic Acid; D012468:Salivary Gland Neoplasms / Q000737:chemistry* / Q000473:pathology; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D002352:Carrier Proteins; D004273:DNA, Neoplasm; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D014212:Tretinoin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors