Abstract
We found that two markers of differentiation, tyrosinase (monophenol, dihydroxyphenylalanine:oxygen oxidoreductase, EC 1.14.18.1) activity and melanin synthesis, are induced by diazepam in B16/C3 mouse melanoma cells. We also demonstrated high-affinity binding sites for [3H]diazepam in these cells by radioreceptor assay, and we visualized binding to the cell surface by fluorescence microscopy with a benzodiazepine analog conjugated to a fluorescein-labeled protein. Our studies also showed that there are differences between the binding characteristics in intact cells and in membrane fractions prepared from these cells. Scatchard analysis of the binding data from membrane fractions gave a linear plot (Kd = 9.1 X 10(-8) M). With intact cells, a curvilinear Scatchard plot was obtained. This was resolved into two components defining binding sites with affinity constants of 1.7 X 10(-9) M and 4.6 X 10(-7) M. Thus, it appears that [3H]diazepam binding in intact cells is more complex than in isolated membranes. Several related benzodiazepines, including flunitrazepam, Ro-5-4864, nitrazepam, oxazepam, lorazepam, Ro-5-3072, chlordiazepoxide, and clonazepam also induced melanogenesis. When these compounds were tested for their ability to inhibit [3H]diazepam binding, flunitrazepam, diazepam, and Ro-5-4864 were found to be the most effective inhibitors. These three compounds were also the most potent in inducing melanogenesis. Our results suggest that the benzodiazepines modulate cell differentiation. The presence of high-affinity binding sites in this homogeneous, easily grown cell line may provide a useful model for studies on the mechanism of action of these compounds.
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- Baraldi M., Guidotti A., Schwartz J. P., Costa E. GABA receptors in clonal cell lines: a model for study of benzodiazepine action at molecular level. Science. 1979 Aug 24;205(4408):821–823. doi: 10.1126/science.462192. [DOI] [PubMed] [Google Scholar]
- Bosmann H. B., Penney D. P., Case K. R., Averill K. Diazepam receptor: specific nuclear binding of [3H]flunitrazepam. Proc Natl Acad Sci U S A. 1980 Feb;77(2):1195–1198. doi: 10.1073/pnas.77.2.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Braestrup C., Albrechtsen R., Squires R. F. High densities of benzodiazepine receptors in human cortical areas. Nature. 1977 Oct 20;269(5630):702–704. doi: 10.1038/269702a0. [DOI] [PubMed] [Google Scholar]
- Braestrup C., Squires R. F. Pharmacological characterization of benzodiazepine receptors in the brain. Eur J Pharmacol. 1978 Apr 1;48(3):263–270. doi: 10.1016/0014-2999(78)90085-7. [DOI] [PubMed] [Google Scholar]
- Braestrup C., Squires R. F. Specific benzodiazepine receptors in rat brain characterized by high-affinity (3H)diazepam binding. Proc Natl Acad Sci U S A. 1977 Sep;74(9):3805–3809. doi: 10.1073/pnas.74.9.3805. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dudai Y., Yavin Z., Yavin E. Binding of [3H]flunitrazepam to differentiating rat cerebral cells in culture. Brain Res. 1979 Nov 16;177(2):418–422. doi: 10.1016/0006-8993(79)90798-4. [DOI] [PubMed] [Google Scholar]
- Duka T., Höllt V., Herz A. In vivo receptor occupation by benzodiazepines and correlation with the pharmacological effect. Brain Res. 1979 Dec 21;179(1):147–156. doi: 10.1016/0006-8993(79)90498-0. [DOI] [PubMed] [Google Scholar]
- FITZPATRICK T. B., BECKER S. W., Jr, LERNER A. B., MONTGOMERY H. Tyrosinase in human skin: demonstration of its presence and of its role in human melanin formation. Science. 1950 Aug 25;112(2904):223–225. doi: 10.1126/science.112.2904.223. [DOI] [PubMed] [Google Scholar]
- Feldman H. A. Mathematical theory of complex ligand-binding systems of equilibrium: some methods for parameter fitting. Anal Biochem. 1972 Aug;48(2):317–338. doi: 10.1016/0003-2697(72)90084-x. [DOI] [PubMed] [Google Scholar]
- Frazier W. A., Boyd L. F., Bradshaw R. A. Properties of the specific binding of 125I-nerve growth factor to responsive peripheral neurons. J Biol Chem. 1974 Sep 10;249(17):5513–5519. [PubMed] [Google Scholar]
- Gonda M. A., Gilden R. V., Hsu K. C. An unlabeled antibody macromolecule technique using hemocyanin for the identification of type B and type C retrovirus envelope and cell surface antigens by correlative fluorescence, transmission electron, and scanning electron microscopy. J Histochem Cytochem. 1979 Nov;27(11):1445–1454. doi: 10.1177/27.11.117048. [DOI] [PubMed] [Google Scholar]
- Huang A., Barker J. L., Paul S. M., Moncada V., Skolnick P. Characterization of benzodiazepine receptors in primary cultures of fetal mouse brain and spinal cord neurons. Brain Res. 1980 May 26;190(2):485–491. doi: 10.1016/0006-8993(80)90290-5. [DOI] [PubMed] [Google Scholar]
- Lader M. Benzodiazepines--the opium of the masses? Neuroscience. 1978;3(2):159–165. doi: 10.1016/0306-4522(78)90098-2. [DOI] [PubMed] [Google Scholar]
- Laskin J. D., Mufson R. A., Weinstein I. B., Engelhardt D. L. Identification of a distinct phase during melanogenesis that is sensitive to extracellular pH and ionic strength. J Cell Physiol. 1980 Jun;103(3):467–474. doi: 10.1002/jcp.1041030312. [DOI] [PubMed] [Google Scholar]
- Limbird L. E., Lefkowitz R. J. Negative cooperativity among beta-adrenergic receptors in frog erythrocyte membranes. J Biol Chem. 1976 Aug 25;251(16):5007–5014. [PubMed] [Google Scholar]
- Möhler H., Okada T. Benzodiazepine receptor: demonstration in the central nervous system. Science. 1977 Nov 25;198(4319):849–851. doi: 10.1126/science.918669. [DOI] [PubMed] [Google Scholar]
- Möhler H., Okada T. Properties of 3H-diazepam binding to benzodiazepine receptors in rat cerebral cortex. Life Sci. 1977 Jun 15;20(12):2101–2110. doi: 10.1016/0024-3205(77)90191-6. [DOI] [PubMed] [Google Scholar]
- Nørby J. G., Ottolenghi P., Jensen J. Scatchard plot: common misinterpretation of binding experiments. Anal Biochem. 1980 Mar 1;102(2):318–320. doi: 10.1016/0003-2697(80)90160-8. [DOI] [PubMed] [Google Scholar]
- Oikawa A., Nakayasu M., Claunch C., Tchen T. T. Two types of melanogenesis in monolayer cultures of melanoma cells. Cell Differ. 1972 Aug;1(3):149–155. doi: 10.1016/0045-6039(72)90024-3. [DOI] [PubMed] [Google Scholar]
- Paul S. M., Syapin P. J., Paugh B. A., Moncada V., Skolnick P. Correlation between benzodiazepine receptor occupation and anticonvulsant effects of diazepam. Nature. 1979 Oct 25;281(5733):688–689. doi: 10.1038/281688a0. [DOI] [PubMed] [Google Scholar]
- Paul S. M., Zatz M., Skolnick P. Demonstration of brain-specific benzodiazepine receptors in rat retina. Brain Res. 1980 Apr 7;187(1):243–246. doi: 10.1016/0006-8993(80)90513-2. [DOI] [PubMed] [Google Scholar]
- Pomerantz S. H. Tyrosine hydroxylation catalyzed by mammalian tyrosinase: an improved method of assay. Biochem Biophys Res Commun. 1964 Jun 1;16(2):188–194. doi: 10.1016/0006-291x(64)90359-6. [DOI] [PubMed] [Google Scholar]
- Rodbard D. Mathematics of hormone-receptor interaction. I. Basic principles. Adv Exp Med Biol. 1973;36(0):289–326. doi: 10.1007/978-1-4684-3237-4_14. [DOI] [PubMed] [Google Scholar]
- Rosenthal H. E. A graphic method for the determination and presentation of binding parameters in a complex system. Anal Biochem. 1967 Sep;20(3):525–532. doi: 10.1016/0003-2697(67)90297-7. [DOI] [PubMed] [Google Scholar]
- STERNBACH L. H., FRYER R. I., KELLER O., METLESICS W., SACH G., STEIGER N. QUINAZOLINES AND 1,4-BENZODIAZEPINES. X. NITRO-SUBSTITUTED 5-PHENYL-1,4-BENZODIAZEPINE DERIVATIVES. J Med Chem. 1963 May;6:261–265. doi: 10.1021/jm00339a010. [DOI] [PubMed] [Google Scholar]
- Schlessinger J., Shechter Y., Willingham M. C., Pastan I. Direct visualization of binding, aggregation, and internalization of insulin and epidermal growth factor on living fibroblastic cells. Proc Natl Acad Sci U S A. 1978 Jun;75(6):2659–2663. doi: 10.1073/pnas.75.6.2659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sieghart W., Karobath M. Molecular heterogeneity of benzodiazepine receptors. Nature. 1980 Jul 17;286(5770):285–287. doi: 10.1038/286285a0. [DOI] [PubMed] [Google Scholar]
- Sonne O., Berg T., Christoffersen T. Binding of 125I-labeled glucagon and glucagon-stimulated accumulation of adenosine 3':5'-monophosphate in isolated intact rat hepatocytes. Evidence for receptor heterogeneity. J Biol Chem. 1978 May 10;253(9):3203–3210. [PubMed] [Google Scholar]
- Squires R. F., Benson D. I., Braestrup C., Coupet J., Klepner C. A., Myers V., Beer B. Some properties of brain specific benzodiazepine receptors: new evidence for multiple receptors. Pharmacol Biochem Behav. 1979 May;10(5):825–830. doi: 10.1016/0091-3057(79)90341-1. [DOI] [PubMed] [Google Scholar]
- Squires R. F., Brastrup C. Benzodiazepine receptors in rat brain. Nature. 1977 Apr 21;266(5604):732–734. doi: 10.1038/266732a0. [DOI] [PubMed] [Google Scholar]
- Strittmatter W. J., Hirata F., Axelrod J., Mallorga P., Tallman J. F., Henneberry R. C. Benzodiazepine and beta-adrenergic receptor ligands independently stimulate phospholipid methylation. Nature. 1979 Dec 20;282(5741):857–859. doi: 10.1038/282857a0. [DOI] [PubMed] [Google Scholar]
- Syapin P. J., Skolnick P. Characterization of benzodiazepine binding sites in cultured cells of neural origin. J Neurochem. 1979 Mar;32(3):1047–1051. doi: 10.1111/j.1471-4159.1979.tb04592.x. [DOI] [PubMed] [Google Scholar]
- Taniguchi T., Wang J. K., Spector S. Properties of [3H] diazepam binding to rat peritoneal mast cells. Life Sci. 1980 Jul 14;27(2):171–178. doi: 10.1016/0024-3205(80)90460-9. [DOI] [PubMed] [Google Scholar]
- de Meyts P., Roth J., Neville D. M., Jr, Gavin J. R., 3rd, Lesniak M. A. Insulin interactions with its receptors: experimental evidence for negative cooperativity. Biochem Biophys Res Commun. 1973 Nov 1;55(1):154–161. doi: 10.1016/s0006-291x(73)80072-5. [DOI] [PubMed] [Google Scholar]