Azepine derivative T4FAT, a new copper chelator, inhibits tyrosinase

Okajima, Sayaka; Hamamoto, Akie; Asano, Masataka; Isogawa, Kenta; Ito, Hironari; Kato, Shinya; Hirata, Yoko; Furuta, Kyoji; Takemori, Hiroshi

doi:10.1016/j.bbrc.2018.12.105

Cited by 18 publications

(18 citation statements)

References 26 publications

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“…Tyrosinase (EC 1.14.18.1) is the central rate-limiting enzyme in the melanogenesis pathway, as it catalyzes the hydroxylation of l -Tyrosine to l -3,4-dihydroxyphenylalanine ( l -DOPA) as well its subsequent oxidation to Dopachrome [ 12 , 13 ]. As tyrosinase is a metalloenzyme with two copper ions; chelators that can sequester copper have also shown promise as a target for pigmentation disorders [ 14 , 15 , 16 ]. The intracellular transport of tyrosinase is regulated by copper uptake and the N-glycosylation process [ 17 ]; the role of the enzyme α-glucosidase has been implicated in this glycosylation process in previous reports [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

CMT-308, a Nonantimicrobial Chemically-Modified Tetracycline, Exhibits Anti-Melanogenic Activity by Suppression of Melanosome Export

Goenka

Simon

2020

Biomedicines

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CMT-308 is a nonantimicrobial chemically-modified tetracycline (CMT), which we have previously shown exhibits antifungal activity and pleiotropic anti-inflammatory activities, including inhibition of the enzymatic activity of matrix metalloproteinases (MMPs). Based on its chemical structure, we hypothesized that CMT-308 could inhibit melanogenesis and might be a candidate for the treatment of skin hyperpigmentation disorders which occur due to unregulated melanin biosynthesis and/or transport. CMT-308 was first studied for any effects on activity of the enzyme tyrosinase in vitro using a purified preparation of mushroom tyrosinase; the mode of inhibition of the soluble fungal enzyme was evaluated by Lineweaver-Burk and Dixon plots as well as by non-linear least squares fitting. Next, the effects of CMT-308 were tested in mammalian cell cultures using B16F10 mouse melanoma cells and further validated in darkly-pigmented human melanocytes (HEMn-DP). Our results showed that micromolar concentrations of CMT-308 inhibited mushroom tyrosinase enzyme activity, using the first two substrates in the melanogenesis pathway (l-tyrosine and l-3,4-dihydroxyphenylalanine (l-DOPA)); CMT-308 inhibited mushroom tyrosinase primarily via a mixed mode of inhibition, with the major contribution from a competitive mode. In B16F10 cell cultures, CMT-308 (10 µM) significantly diminished total melanin levels with a selective reduction of extracellular melanin levels, under both basal and hormone-stimulated conditions without any cytotoxicity over a duration of 72 h. Studies of potential mechanisms of inhibition of melanogenesis in B16F10 cells showed that, in mammalian cells, CMT-308 did not inhibit intracellular tyrosinase activity or the activity of α-glucosidase, an enzyme that regulates maturation of tyrosinase. However, CMT-308 suppressed MITF protein expression in B16F10 cells and showed copper chelating activity and antioxidant activity in a cell-free system. The significantly lower extracellular melanin levels obtained at 10 µM indicate that CMT-308’s anti-melanogenic action may be attributed to a selective inhibition of melanosome export with the perinuclear aggregation of melanosomes, rather than a direct effect on the tyrosinase-catalyzed steps in melanin biosynthesis. These results were validated in HEMn-DP cells where CMT-308 suppressed dendricity in a fully reversible manner without affecting intracellular melanin synthesis. Furthermore, the capacity of CMT-308 to inhibit melanosome export was retained in cocultures of HEMn-DP and HaCaT. In summary, our results offer promise for therapeutic strategies to combat the effects of hyperpigmentation by use of CMT-308 at low micromolar concentrations.

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Section: Introductionmentioning

confidence: 99%

CMT-308, a Nonantimicrobial Chemically-Modified Tetracycline, Exhibits Anti-Melanogenic Activity by Suppression of Melanosome Export

Goenka

Simon

2020

Biomedicines

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“…To explore new melanogenesis inhibitors, we screened a chemical library composed of 2000 compounds 23 and identified 4‐OST as a candidate inhibitor (Figure 1A). A total of 10 µM of 4‐OST inhibited melanogenesis in B16F10 cells that were stimulated with 10 µM of forskolin (cAMP agonist) (Figure 1B).…”

Section: Resultsmentioning

confidence: 99%

Thioxothiazolidin derivative, 4‐OST, inhibits melanogenesis by enhancing the specific recruitment of tyrosinase‐containing vesicles to lysosome

Isogawa

Asano

Hayazaki

et al. 2021

J of Cellular Biochemistry

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Tyrosinase catalyzes the rate‐limiting step in melanin synthesis. Melanin is synthesized from l‐tyrosin in the melanosomes, where tyrosinase and other melanogenic factors are recruited via the vesicle transport system. Genetic and biochemical approaches have revealed a correlation between impairments in the vesicle transport system and albinism. However, the specificity of the individual transport systems for the corresponding melanogenic factors has not been well elucidated yet. Here, we report that the thioxothiazolidin derivative, 4‐OST (4‐[(5E)‐5‐[(4‐fluorophenyl)methylidene]‐4‐oxo‐2‐sulfanylidene‐1,3‐thiazolidin‐3‐yl]‐4‐azatricyclo [5.2.1.02,6]dec‐8‐ene‐3,5‐dione: CAS RN. 477766‐87‐3) strongly inhibited melanogenesis in mouse melanoma B16F10 cells. 4‐OST reduces tyrosinase protein levels without affecting its messenger RNA levels or enzymatic activity. Although a reduction in tyrosinase protein level was observed in the presence of a protein synthesis inhibitor, the reduction may be coupled with protein synthesis. Similarly, GIF‐2202 (a derivative of 4‐OST) lowers tyrosinase protein levels without affecting the levels of another melanogenic enzyme, tyrosinase‐related protein 1 (TYRP1) level. The reduction in tyrosinase protein level is associated with an increase in the levels of the lysosomal proteinase cathepsin S. Chloroquine, a lysosome inhibitor, restored the tyrosinase protein level downregulated by GIF‐2202, although no effects of other inhibitors (against proteasome, autophagy, or exocytosis) were observed. In addition, GIF‐2202 segregated the immunofluorescence signals of tyrosinase from those of TYRP1. Chloroquine treatment resulted in co‐localization of tyrosinase and cathepsin S signals near the perinuclear region, suggesting that 4‐OST and GIF‐2202 may alter the destination of the tyrosinase vesicle from the melanosome to the lysosome. 4‐OST and GIF‐2202 can be new tools for studying the tyrosinase‐specific vesicle transport system.

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“…Kojic acid can competitively inhibit TYR activity through a mechanism involving copper cheating activity [24]. In addition, numerous hydroxamic acid derivatives can chelate metal ions and inhibit metalloenzymes such as TYRs and HDACs [53,54].…”

Section: Discussionmentioning

confidence: 99%

“…Copper chelating activity was determined by using pyrocatechol violet (Sigma-Aldrich) [24]. The principle of this method is that, when the pyrocatechol violet is complexed with copper, it shows maximum absorption at 632 nm, and the test material competing with pyrocatechol violet for copper can reduce the absorbance of the copper-pyrocatechol violet complex.…”

Section: Copper Chelating Activity Assaymentioning

confidence: 99%

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Screening of an Epigenetic Drug Library Identifies 4-((hydroxyamino)carbonyl)-N-(2-hydroxyethyl)-N-Phenyl-Benzeneacetamide that Reduces Melanin Synthesis by Inhibiting Tyrosinase Activity Independently of Epigenetic Mechanisms

Song

Hwang

et al. 2020

IJMS

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The aim of this study was to identify novel antimelanogenic drugs from an epigenetic screening library containing various modulators targeting DNA methyltransferases, histone deacetylases, and other related enzymes/proteins. Of 141 drugs tested, K8 (4-((hydroxyamino)carbonyl)-N-(2-hydroxyethyl)-N-phenyl-benzeneacetamide; HPOB) was found to effectively inhibit the α-melanocyte-stimulating hormone (α-MSH)-induced melanin synthesis in B16-F10 murine melanoma cells without accompanying cytotoxicity. Additional experiments showed that K8 did not significantly reduce the mRNA and protein level of tyrosinase (TYR) or microphthalmia-associated transcription factor (MITF) in cells, but it potently inhibited the catalytic activity TYR in vitro (IC50, 1.1–1.5 µM) as compared to β-arbutin (IC50, 500–700 µM) or kojic acid (IC50, 63 µM). K8 showed copper chelating activity similar to kojic acid. Therefore, these data suggest that K8 inhibits cellular melanin synthesis not by downregulation of TYR protein expression through an epigenetic mechanism, but by direct inhibition of TYR catalytic activity through copper chelation. Metal chelating activity of K8 is not surprising because it is known to inhibit histone deacetylase (HDAC) 6 through zinc chelation. This study identified K8 as a potent inhibitor of cellular melanin synthesis, which may be useful for the treatment of hyperpigmentation disorders

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Azepine derivative T4FAT, a new copper chelator, inhibits tyrosinase

Cited by 18 publications

References 26 publications

CMT-308, a Nonantimicrobial Chemically-Modified Tetracycline, Exhibits Anti-Melanogenic Activity by Suppression of Melanosome Export

CMT-308, a Nonantimicrobial Chemically-Modified Tetracycline, Exhibits Anti-Melanogenic Activity by Suppression of Melanosome Export

Thioxothiazolidin derivative, 4‐OST, inhibits melanogenesis by enhancing the specific recruitment of tyrosinase‐containing vesicles to lysosome

Screening of an Epigenetic Drug Library Identifies 4-((hydroxyamino)carbonyl)-N-(2-hydroxyethyl)-N-Phenyl-Benzeneacetamide that Reduces Melanin Synthesis by Inhibiting Tyrosinase Activity Independently of Epigenetic Mechanisms

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