{"title":"Low-dose imiquimod induces melanogenesis in melanoma cells through an ROS-mediated pathway","authors":"Zheng-Yi Li, Shu-Hao Chang, Kuang-Ting Liu, Alaina Edelie Wu, Chien-Sheng Hsu, Shi-Wei Huang, Mu-Chi Chung, Shih-Chung Wang, Jun-Kai Kao, Yi-Ju Chen, Jeng-Jer Shieh","doi":"10.1016/j.jdermsci.2023.12.005","DOIUrl":null,"url":null,"abstract":"<h3>Background</h3><p>Melanogenesis is the process of melanin maturation which not only protects skin from UV radiation but also plays an important role in antigenicity of melanomas. Imiquimod (IMQ) is a toll-like receptor 7 (TLR7) agonist that exhibits antiviral and anticancer activity.</p><h3>Objective</h3><p>To explore whether IMQ could induce melanogenesis in melanoma cells.</p><h3>Methods</h3><p>The mouse melanoma cell line B16F10, the mouse immortalized melanocyte Melan-A, and human melanoma cell lines MNT-1, C32 and A375 were utilized in this study. The pigmented level was observed by the centrifuged cell pellet. The intracellular and extracellular melanin levels were examined in the absorbance in NaOH-extracted cell lysate and cell-cultured medium, respectively. The expression of melanogenesis related proteins was examined by immunoblotting. The intracellular cyclic AMP amount was evaluated by the cAMP Glo assay kit. The activity of phosphodiesterase 4B (PDE4B) was investigated by CREB reporter assay with overexpressed PDE4B or not.</p><h3>Results</h3><p>We demonstrated that a low dose of IMQ could trigger melanogenesis in B16F10 cells. IMQ induced microphthalmia-associated transcription factor (MITF) nuclear translocation, upregulated the expression of melanogenesis-related proteins, increased tyrosinase (TYR) activity, and led to pigmentation in B16F10 cells. Next, we found that IMQ-induced melanogenesis was activated by excessive intracellular cAMP accumulation, which was regulated through IMQ-mediated PDE4B inhibition. Finally, IMQ-induced ROS production was found to be involved in melanogenesis by its control of PDE4B activity.</p><h3>Conclusions</h3><p>Low dose of IMQ could activate melanogenesis through the ROS/PDE4B/PKA pathway in melanoma cells.</p>","PeriodicalId":15641,"journal":{"name":"Journal of dermatological science","volume":null,"pages":null},"PeriodicalIF":3.8000,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of dermatological science","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1016/j.jdermsci.2023.12.005","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"DERMATOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background
Melanogenesis is the process of melanin maturation which not only protects skin from UV radiation but also plays an important role in antigenicity of melanomas. Imiquimod (IMQ) is a toll-like receptor 7 (TLR7) agonist that exhibits antiviral and anticancer activity.
Objective
To explore whether IMQ could induce melanogenesis in melanoma cells.
Methods
The mouse melanoma cell line B16F10, the mouse immortalized melanocyte Melan-A, and human melanoma cell lines MNT-1, C32 and A375 were utilized in this study. The pigmented level was observed by the centrifuged cell pellet. The intracellular and extracellular melanin levels were examined in the absorbance in NaOH-extracted cell lysate and cell-cultured medium, respectively. The expression of melanogenesis related proteins was examined by immunoblotting. The intracellular cyclic AMP amount was evaluated by the cAMP Glo assay kit. The activity of phosphodiesterase 4B (PDE4B) was investigated by CREB reporter assay with overexpressed PDE4B or not.
Results
We demonstrated that a low dose of IMQ could trigger melanogenesis in B16F10 cells. IMQ induced microphthalmia-associated transcription factor (MITF) nuclear translocation, upregulated the expression of melanogenesis-related proteins, increased tyrosinase (TYR) activity, and led to pigmentation in B16F10 cells. Next, we found that IMQ-induced melanogenesis was activated by excessive intracellular cAMP accumulation, which was regulated through IMQ-mediated PDE4B inhibition. Finally, IMQ-induced ROS production was found to be involved in melanogenesis by its control of PDE4B activity.
Conclusions
Low dose of IMQ could activate melanogenesis through the ROS/PDE4B/PKA pathway in melanoma cells.
期刊介绍:
Although the Journal is the official organ of the Japanese Society for Investigative Dermatology, it serves as an international forum for the work of all dermatological scientists. With an internationally renowned Editorial Board, the Journal maintains high scientific standards in the evaluation and publication of manuscripts. The Journal also publishes invited reviews, commentaries, meeting announcements and book reviews. Letters to the Editor reporting new results or even negative scientific data, if they contribute to advances in dermatology are encouraged. Letters to the Editor should be less than 1000 words with up to 2 figures or tables.