1
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Luo J, Ren Q, Liu X, Zheng Q, Yang L, Meng M, Ma H, He S. LncRNA MALAT-1 modulates EGFR-TKI resistance in lung adenocarcinoma cells by downregulating miR-125. Discov Oncol 2024; 15:379. [PMID: 39196297 PMCID: PMC11358566 DOI: 10.1007/s12672-024-01133-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 06/28/2024] [Indexed: 08/29/2024] Open
Abstract
Molecular targeted therapy resistance remains a major challenge in treating lung adenocarcinoma (LUAD). The resistance of Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs, epidermal growth factor receptor-tyrosine kinase inhibitor) plays a dominant role in molecular targeted therapy. Our previous research demonstrated the role of MALAT-1 (Metastasis-associated lung adenocarcinoma transcript 1) in the formation of Erlotinib-resistant LUAD cells. This study aims to uncover the mechanism of MALAT-1 overexpression in Erlotinib-resistant LUAD cells. The RT2 LncRNA PCR array system was used to explore MALAT-1 regulation in Erlotinib-resistant LUAD cells through patient serum analysis. Dual luciferase reporter experiments confirmed the binding between MALAT-1 and miR-125, leading to regulation of miR-125 expression. Functional assays were performed to elucidate the impact of MALAT1 on modulating drug resistance, growth, and Epithelial-mesenchymal transition (EMT, Epithelial-mesenchymal transition) in both parental and Erlotinib-resistant LUAD cells. The investigation unveiled the mechanism underlying the competing endogenous RNA (ceRNA, competing endogenouse RNA) pathway. MALAT1 exerted its regulatory effect on miR-125 as a competing endogenous RNA (ceRNA). Moreover, MALAT1 played a role in modulating the sensitivity of LUAD cells to Erlotinib. Rab25 was identified as the direct target of miR-125 and mediated the functional effects of MALAT1 in Erlotinib-resistant LUAD cells. In conclusion, our study reveals overexpress MALAT-1 cause the drug resistance of EGFR-TKIs in non-small cell lung cancer (NSCLC) through the MALAT-1/miR-125/Rab25 axis. These findings present a potential novel therapeutic target and perspective for the treatment of LUAD.
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Affiliation(s)
- Jie Luo
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Zunyi Medical University, Zunyi, China
| | - Qiaoya Ren
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Zunyi Medical University, Zunyi, China
| | | | - Qian Zheng
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Zunyi Medical University, Zunyi, China
| | - Ling Yang
- Department of Pathology, Suining Central Hospital, Suining, Sichuan, China
| | - Mi Meng
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Hu Ma
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China.
- Zunyi Medical University, Zunyi, China.
| | - Sisi He
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Zunyi Medical University, Zunyi, China
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2
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Chaudhary A, Patel M, Singh S. Current Debates on Etiopathogenesis and Treatment Strategies for Vitiligo. Curr Drug Targets 2022; 23:1219-1238. [PMID: 35388753 DOI: 10.2174/1389450123666220406125645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/12/2021] [Accepted: 12/31/2021] [Indexed: 01/25/2023]
Abstract
Vitiligo is an acquired, chronic, and progressive depigmentation or hypopigmentation characterized by the destruction of melanocytes and the occurrence of white patches or macules in the skin, mucosal surface of eyes, and ears. Melanocytes are the melanin pigment-producing cells of the skin which are destroyed in pathological conditions called vitiligo. Approximately 0.5 - 2.0% of the population is suffering from vitiligo, and a higher prevalence rate of up to 8.8% has been reported in India. It is caused by various pathogenic factors like genetic predisposition, hyperimmune activation, increased oxidative stress, and alteration in neuropeptides level. Genetic research has revealed a multi- genetic inheritance that exhibits an overlap with other autoimmune disorders. However, melanocytes specific genes are also affected (such as DDR1, XBP1, NLRP1, PTPN22, COMT, FOXP3, ACE, APE, GSTP1, TLR, SOD, and CTLA-4). A number of therapeutic options are employed for the treatment of vitiligo. The topical corticosteroids and immunomodulators are currently in practice for the management of vitiligo. Phototherapies alone and in combinations with other approaches are used in those patients who do not respond to the topical treatment. The main focus of this review is on the etiopathological factors, pharmacological management (phototherapy, topical, systemic, and surgical therapy), and herbal drugs used to treat vitiligo.
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Affiliation(s)
- Ankit Chaudhary
- Department of Pharmacology, Neuropharmacology Division, ISF College of Pharmacy, Moga, Punjab 142001, India
| | - Mayank Patel
- Department of Pharmacology, Neuropharmacology Division, ISF College of Pharmacy, Moga, Punjab 142001, India
| | - Shamsher Singh
- Department of Pharmacology, Neuropharmacology Division, ISF College of Pharmacy, Moga, Punjab 142001, India
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3
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Hayazaki M, Hatano O, Shimabayashi S, Akiyama T, Takemori H, Hamamoto A. Zebrafish as a new model for rhododendrol-induced leukoderma. Pigment Cell Melanoma Res 2021; 34:1029-1038. [PMID: 34310852 DOI: 10.1111/pcmr.13005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/29/2021] [Accepted: 07/16/2021] [Indexed: 01/12/2023]
Abstract
Idiopathic leukoderma is a skin disorder characterized by patchy loss of skin pigmentation due to melanocyte dysfunction or deficiency. Rhododendrol (RD) was approved as a cosmetic ingredient in Japan in 2008. However, it was shown to induce leukoderma in approximately 20,000 customers. The prediction of cytotoxicity, especially to melanocytes in vivo, is required to avoid such adverse effects. Since the use of higher vertebrates is prohibited for medicinal and toxicological assays, we used zebrafish, whose melanocytes were regulated by mechanisms similar to mammals. Zebrafish larvae were treated with RD in breeding water for 3 days, which caused body lightening accompanied by a decrease in the number of melanophores. Interestingly, black particles were found at the bottom of culture dishes, suggesting that the melanophores peeled off from the body. In addition, RT-PCR analysis suggested that the mRNA levels of melanophore-specific genes were significantly low. An increase in the production of reactive oxygen species was found in larvae treated with RD. The treatments of the fish with other phenol compounds, which have been reported to cause leukoderma, also induced depigmentation and melanophore loss. These results suggest that zebrafish larvae could be used for the evaluation of leukoderma caused by chemicals, including RD.
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Affiliation(s)
- Masumi Hayazaki
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, Japan
| | - Osamu Hatano
- Department of Basic Medicine, Nara Medical University School of Medicine, Kashihara, Japan
| | - Saki Shimabayashi
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, Japan
| | - Takumi Akiyama
- Division of Environmental Chemistry, National Institute of Health Sciences, Kawasaki, Japan
| | - Hiroshi Takemori
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, Japan
| | - Akie Hamamoto
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, Japan
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4
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Wu X, Yang Y, Xiang L, Zhang C. The fate of melanocyte: Mechanisms of cell death in vitiligo. Pigment Cell Melanoma Res 2020; 34:256-267. [PMID: 33346939 DOI: 10.1111/pcmr.12955] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/10/2020] [Indexed: 01/20/2023]
Abstract
Loss of melanocytes (MCs) is the most notable feature of vitiligo. Hence, it is critical to clarify the mechanisms of MC destruction in vitiligo. Apoptosis is most widely studied cell death pathways in vitiligo. In addition, the other two forms of cell death, conventional necrosis and autophagy seem to be involved in the death of vitiligo MCs under certain situations. Moreover, new types of regulated cell death including necroptosis, pyroptosis, and ferroptosis may also participate in the pathogenesis of vitiligo. Anoikis is likely to be connected with the death of detached MCs, which is provoked specifically by loss of anchorage. Primary phagocytosis, later called phagoptosis can execute death of viable cells, probably partly responsible for the loss of MCs in vitiligo. In this review, we aim to summarize the latest insights into various forms of MC death in vitiligo and discuss the corresponding mechanisms.
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Affiliation(s)
- Xiuyi Wu
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Yiwen Yang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Leihong Xiang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Chengfeng Zhang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
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5
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Abstract
Vitiligo is an autoimmune disease of the skin that targets pigment-producing melanocytes and results in patches of depigmentation that are visible as white spots. Recent research studies have yielded a strong mechanistic understanding of this disease. Autoreactive cytotoxic CD8+ T cells engage melanocytes and promote disease progression through the local production of IFN-γ, and IFN-γ-induced chemokines are then secreted from surrounding keratinocytes to further recruit T cells to the skin through a positive-feedback loop. Both topical and systemic treatments that block IFN-γ signaling can effectively reverse vitiligo in humans; however, disease relapse is common after stopping treatments. Autoreactive resident memory T cells are responsible for relapse, and new treatment strategies focus on eliminating these cells to promote long-lasting benefit. Here, we discuss basic, translational, and clinical research studies that provide insight into the pathogenesis of vitiligo, and how this insight has been utilized to create new targeted treatment strategies.
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Affiliation(s)
- Michael L. Frisoli
- University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA;, ,
| | - Kingsley Essien
- University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA;, ,
| | - John E. Harris
- University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA;, ,
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6
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Pérez-Albaladejo E, Lacorte S, Porte C. Differential Toxicity of Alkylphenols in JEG-3 Human Placental Cells: Alteration of P450 Aromatase and Cell Lipid Composition. Toxicol Sci 2020; 167:336-346. [PMID: 30247713 DOI: 10.1093/toxsci/kfy243] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alkylphenols (APs) are a diverse class of chemicals that can cross the placental barrier and interfere with embryonic and fetal development. This work investigates the comparative toxicity, ability to inhibit aromatase activity, and to alter the lipid composition of 10 alkylphenols in the human placenta choriocarcinoma cell line JEG-3. Among the selected APs, 4-dodecylphenol (DP), 4-heptylphenol (HP), and 4-cumylphenol (CP) showed the highest cytotoxicity (EC50: 18-65 µM). Aromatase inhibition was closely related to the hydrophobicity of APs. HP significantly induced the generation of reactive oxygen species (ROS) (43-fold), inhibited placental aromatase activity (IC50: 41 µM), and induced a general dose-dependent depletion of polyunsaturated lipids (10-20 µM), which were attributed to high levels of oxidative stress. In contrast, 2,4,6-tri-tert-butylphenol (TTBP) significantly induced the intracellular accumulation of triacylglycerides (TGs), whereas DP increased the synthesis of phosphatidylcholines (PCs) and TGs at the expense of diacylglycerides (DGs). Overall, this study evidences the different modes of action of alkylphenols in human placental JEG-3 cells, describes differential lipidomic fingerprints, and highlights DP, HP, CP, and TTBP as the ones that caused the most harmful effects.
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Affiliation(s)
| | - Silvia Lacorte
- Environmental Chemistry Department, IDAEA-CSIC, C/Jordi Girona 18-26, Barcelona 08034, Spain
| | - Cinta Porte
- Environmental Chemistry Department, IDAEA-CSIC, C/Jordi Girona 18-26, Barcelona 08034, Spain
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7
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Sugimoto M, Manggara AB, Yoshida K, Inoue T, Ideo T. An Electronic-structure Informatics Study on the Toxicity of Alkylphenols to Tetrahymena pyriformis. Mol Inform 2020; 39:e1900121. [PMID: 31930704 DOI: 10.1002/minf.201900121] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/18/2019] [Indexed: 01/29/2023]
Abstract
Alkylphenols (APs) dissolved in water are known to be toxic to animals including humans. In this study, regression models describing the toxicity of the 33 AP molecules were investigated for reproducing and thereby making it possible to predict a quantitative structure-activity relationship (QSAR). For this purpose, we tried to derive regression models for the experimental IGC50 (growth inhibition concentration at 50 %) to Tetrahymena pyriformis by using various descriptor sets consisting of electronic and shape descriptors. By applying the multiple linear regression (MLR) analysis, it was successful to derive a quantitative regression model for the IGC50 values. In this analysis, the size parameters of the molecules were found important, suggesting that bulky molecules should be less toxic. We could also obtain, when the size descriptors were excluded, an MLR model indicating that the electron affinity (EA) should be important, which is consistent with the previous QSAR studies. Through the correlation analysis among the descriptors, it was shown that, in the present set of molecules, EA and a size parameter are highly correlated. Since EA was calculated to be negative, indicating that the related process would be energetically unfavourable, it was concluded that the size of the molecules should be a dominant factor determining IGC50 . This implies that a molecular recognition process would play a critical role in the mode of action for the toxicity.
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Affiliation(s)
- Manabu Sugimoto
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan.,Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan
| | - Algafari Bakti Manggara
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan
| | - Kazuki Yoshida
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan
| | - Takafumi Inoue
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan
| | - Toshihiro Ideo
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, 860-8555, Kumamoto, Japan
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8
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Kammeyer A, Willemsen KJ, Ouwerkerk W, Bakker WJ, Ratsma D, Pronk SD, Smit NPM, Luiten RM. Mechanism of action of 4-substituted phenols to induce vitiligo and antimelanoma immunity. Pigment Cell Melanoma Res 2019; 32:540-552. [PMID: 30767390 PMCID: PMC6850206 DOI: 10.1111/pcmr.12774] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 12/20/2018] [Accepted: 02/01/2019] [Indexed: 12/22/2022]
Abstract
Monobenzone is a 4-substituted phenol that can induce vitiligo and antimelanoma immunity. We investigated the influence of the chemical structure on the biological activity of a series of structurally related 4-substituted phenols. All phenols inhibited cellular melanin synthesis, and eight of ten phenols inhibited tyrosinase activity, using the MBTH assay. These phenols also induced glutathione (GSH) depletion, indicative of quinone formation and protein thiol binding, which can increase the immunogenicity of melanosomal proteins. Specific T-cell activation was found upon stimulation with phenol-exposed pigmented cells, which also reacted with unexposed cells. In contrast, 4-tertbutylphenol induced immune activation was not restricted to pigment cells, analogous to contact sensitization. We conclude that 4-substituted phenols can induce specific T-cell responses against melanocytes and melanoma cells, also acting at distant, unexposed body sites, and may confer a risk of chemical vitiligo. Conversely, these phenols may be applicable to induce specific antimelanoma immunity.
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Affiliation(s)
- Arthur Kammeyer
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Karin J. Willemsen
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Wouter Ouwerkerk
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
- Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical CentersUniversity of AmsterdamAmsterdamThe Netherlands
| | - Walbert J. Bakker
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Danielle Ratsma
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Sebas D. Pronk
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
| | - Nico P. M. Smit
- Department of Clinical Chemistry and Laboratory MedicineLeiden University Medical CenterLeidenThe Netherlands
| | - Rosalie M. Luiten
- Department of Dermatology and Netherlands Institute for Pigment Disorders, Amsterdam University Medical Centers, Amsterdam Infection & Immunity Institute, Cancer Center AmsterdamUniversity of AmsterdamAmsterdamThe Netherlands
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9
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Pyo JJ, Ahn S, Jin SH, An S, Lee E, Choi J, Shin JC, Choi H, Kim HJ, Choi D, Noh M. Keratinocyte-derived IL-36γ plays a role in hydroquinone-induced chemical leukoderma through inhibition of melanogenesis in human epidermal melanocytes. Arch Toxicol 2019; 93:2307-2320. [PMID: 31256213 DOI: 10.1007/s00204-019-02506-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/26/2019] [Indexed: 01/12/2023]
Abstract
Chemical leukoderma is an acquired type of vitiligo that can be initiated by various exogenous chemicals such as hydroquinone (HQ), rhododendrol (RD), or 4-tertiary butyl phenol (4-TBP). Despite the importance of epidermal keratinocytes in diverse dermatological conditions, their toxicological role in chemical leukoderma is poorly understood. To elucidate their role in the pathogenesis of chemical leukoderma, genome-scale transcriptional analysis was performed in human epidermal keratinocytes (HEKs) treated with a sub-cytotoxic HQ concentration (10 µM). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway-based functional enrichment analysis of HQ-induced differentially expressed genes (DEGs) revealed that HQ significantly upregulated DEGs related to the IL-17 signaling pathway and significantly downregulated DEGs associated with melanogenesis in HEKs. The meta-analysis between the HQ-induced and cytokine-induced transcriptional data (GSE53751) showed that 58 DEGs were commonly upregulated between HQ- and IL-17A-treated HEKs. Notably, the expression of IL36G was significantly increased in HEKs in response to both HQ and IL-17A. IL-36γ (2 µg/ml) directly inhibits melanin biosynthesis in cultured human epidermal melanocytes (HEMs) and downregulates the gene transcription of key enzymes in the melanogenesis pathway including TYR, DCT, and TYRP1. Moreover, IL-36γ autocrinally regulated keratinocyte function to produce the proinflammatory cytokines IL-36γ, IL-6, and CXCL8/IL-8 in a concentration-dependent manner, suggesting that IL-36γ may stimulate the amplification cycle of cutaneous inflammation. In this regard, hydroquinone-induced IL-36γ from human keratinocytes plays a pivotal role in the development of chemical leukoderma by autocrinally or paracrinally modulating the crosstalk between keratinocytes and melanocytes.
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Affiliation(s)
- Jeong Joo Pyo
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sungjin Ahn
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sun Hee Jin
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seungchan An
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Eunyoung Lee
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jungmin Choi
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jeayoung C Shin
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea.,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hyunjung Choi
- AmorePacific Corporation R&D Center, Yongin, Gyeounggi-do, 17074, Republic of Korea
| | - Hyoung-June Kim
- AmorePacific Corporation R&D Center, Yongin, Gyeounggi-do, 17074, Republic of Korea
| | - Dalwoong Choi
- Department of Public Health Science, Graduate School and College of Public Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - Minsoo Noh
- College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea. .,Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
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10
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Chen J, Liu X, Xu Y, Zhang K, Huang J, Pan B, Chen D, Cui S, Song H, Wang R, Chu X, Zhu X, Chen L. TFAP2C-Activated MALAT1 Modulates the Chemoresistance of Docetaxel-Resistant Lung Adenocarcinoma Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 14:567-582. [PMID: 30771618 PMCID: PMC6374643 DOI: 10.1016/j.omtn.2019.01.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 02/07/2023]
Abstract
Chemoresistance remains a great obstacle in effective lung adenocarcinoma (LUAD) treatment. Previously, we verified the role of microRNA-200b (miR-200b) in the formation of docetaxel (DTX)-resistant LUAD cells. This study aims to investigate the mechanism underlying the low level of miR-200b in DTX-resistant LUAD cells. The real-time reverse transcription (RT2) lncRNA PCR array system was applied to explore lncRNAs that potentially regulated miR-200b in DTX-resistant LUAD cells. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) contributed to the low miR-200b level in DTX-resistant LUAD cells. Functional assays were conducted to determine the role of MALAT1 in regulating the growth and metastasis of parental and DTX-resistant LUAD cells. Investigation revealed the mechanism of the competing endogenous RNA (ceRNA) pathway. MALAT1 regulated miR-200b by acting as a ceRNA. MALAT1 modulated the sensitivity of LUAD cells to DTX. E2F transcription factor 3 (E2F3) and zinc-finger E-box binding homeobox 1 (ZEB1) were two targets of miR-200b and mediated the function of MALAT1 in DTX-resistant LUAD cells. Transcription factor AP-2 gamma (TFAP2C) and ZEB1 activated the MALAT1 transcription. In conclusion, TFAP2C-activated MALAT1 modulated the chemoresistance of LUAD cells by sponging miR-200b to upregulate E2F3 and ZEB1. Our findings may provide novel therapeutic targets and perspectives for LUAD treatment.
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Affiliation(s)
- Jing Chen
- Department of Respiratory, Zhongda Hospital, Southeast University, Nanjing, China; Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Xiaobei Liu
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Yichen Xu
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Kai Zhang
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Jiayuan Huang
- Department of Medical Oncology, Jiangsu Cancer Hospital Affiliated to Nanjing Medical University, Jiangsu Institute of Cancer Research, Jiangsu, China
| | - Banzhou Pan
- Department of Medical Oncology, Jiangsu Cancer Hospital Affiliated to Nanjing Medical University, Jiangsu Institute of Cancer Research, Jiangsu, China
| | - Dongqin Chen
- Department of Medical Oncology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Shiyun Cui
- Department of Medical Oncology, The First Affiliated Hospital of Nanjing Medical University, Suzhou, Jiangsu, China
| | - Haizhu Song
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Rui Wang
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Xiaoyuan Chu
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China
| | - Xiaoli Zhu
- Department of Respiratory, Zhongda Hospital, Southeast University, Nanjing, China.
| | - Longbang Chen
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
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11
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Abstract
Chemical-induced depigmentation of the skin has been recognized for more than 75 years, first as an occupational hazard but then extending to those using household commercial products as common as hair dyes. Since their discovery, these chemicals have been used therapeutically in patients with severe vitiligo to depigment their remaining skin and improve their appearance. Because chemical-induced depigmentation is clinically and histologically indistinguishable from nonchemically induced vitiligo, and because these chemicals appear to induce melanocyte autoimmunity, this phenomenon should be known as "chemical-induced vitiligo," rather than less accurate terms that have been previously used.
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Affiliation(s)
- John E Harris
- Department of Dermatology, University of Massachusetts Medical School, 364 Plantation Street, LRB 225, Worcester, MA 01605, USA.
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12
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Li Y, Liu H, Shao J, Xing G. miR-320a serves as a negative regulator in the progression of gastric cancer by targeting RAB14. Mol Med Rep 2017; 16:2652-2658. [PMID: 28713899 PMCID: PMC5547933 DOI: 10.3892/mmr.2017.6937] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 05/02/2017] [Indexed: 12/24/2022] Open
Abstract
Gastric cancer (GC) is one of the most common types of malignancy worldwide, with high morbidity and mortality rates. The dysregulation of microRNAs (miRs) has been found to be involved in the carcinogenesis of GC. The present study aimed to investigate the underlying association between GC and miR-320a. Analysis using reverse transcription quantitative polymerase chain reaction indicated that the expression of miR-320a was downregulated and the expression of RAB14 was upregulated in GC tissues and cells, compared with the corresponding controls. MTT, colony formation assays, and flow cytometric analyses were used to evaluate the effect of miR-320a on cell proliferation and the cell cycle. The ectopic expression of miR-320a using miR-320a mimics suppressed cell viability, inhibited G1/S transition, and induced apoptosis in AGS and MKN45 cells. In addition, RAB14 was identified as a direct target gene of miR-320a, according to the results of bioinformatics analysis and a luciferase reporter assay. Downregulation of RAB14 by RAB14-small interfering RNA inhibited the viability of GC cells, which was similar to the phenotype of miR-320a mimics. Furthermore, the reintroduction of RAB14 partially abrogated the miR-320a-mediated downregulation of RAB14 and rescued the miR-320a-induced effects on GC cell growth. These findings suggest a potential novel therapeutic target for the treatment of GC.
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Affiliation(s)
- Yongyuan Li
- Department of General Surgery, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
| | - Hongjie Liu
- Department of Radiology, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
| | - Jianping Shao
- Department of General Surgery, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
| | - Guoqiang Xing
- Department of General Surgery, The Fifth Central Hospital of Tianjin, Tianjin 300450, P.R. China
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Strassner JP, Harris JE. Understanding mechanisms of autoimmunity through translational research in vitiligo. Curr Opin Immunol 2016; 43:81-88. [PMID: 27764715 DOI: 10.1016/j.coi.2016.09.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/30/2016] [Accepted: 09/30/2016] [Indexed: 12/18/2022]
Abstract
Vitiligo is an autoimmune disease of the skin that leads to life-altering depigmentation and remains difficult to treat. However, clinical observations and translational studies over 30-40 years have led to the development of an insightful working model of disease pathogenesis: Genetic risk spanning both immune and melanocyte functions is pushed over a threshold by known and suspected environmental factors to initiate autoimmune T cell-mediated killing of melanocytes. While under cellular stress, melanocytes appear to signal innate immunity to activate T cells. Once the autoimmune T cell response is established, the IFN-γ-STAT1-CXCL10 signaling axis becomes the primary inflammatory pathway driving both progression and maintenance of vitiligo. This pathway is a tempting target for both existing and developing pharmaceuticals, but further detailing how melanocytes signal their own demise may also lead to new therapeutic targets. Research in vitiligo may be the future key to understand the pathogenesis of organ-specific autoimmunity, as vitiligo is common, reversible, progresses over the life of the individual, has been relatively well-defined, and is quite easy to study using translational and clinical approaches. What is revealed in these studies can lead to innovative treatments and also help elucidate the principles that underlie similar organ-specific autoimmune diseases, especially in cases where the target organ is less accessible.
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Affiliation(s)
- James P Strassner
- Department of Medicine, Division of Dermatology, University of Massachusetts Medical School, 364 Plantation St., LRB 225, Worcester, MA 01605, USA
| | - John E Harris
- Department of Medicine, Division of Dermatology, University of Massachusetts Medical School, 364 Plantation St., LRB 225, Worcester, MA 01605, USA.
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Wu Y, Shi J, Chen H, Zhao J, Dong W. Aqueous photodegradation of 4-tert-butylphenol: By-products, degradation pathway and theoretical calculation assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:86-92. [PMID: 27213674 DOI: 10.1016/j.scitotenv.2016.05.064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/09/2016] [Accepted: 05/10/2016] [Indexed: 05/17/2023]
Abstract
4-tert-butylphenol (4-t-BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4-t-BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC-MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4-t-BP by hydroxyl radical (HO) was also studied and H2O2 was added to produce HO. 4-tert-butylcatechol and 4-tert-butylphenol dimer were produced in 4-t-BP direct photolysis. 4-tert-butylcatechol and hydroquinone were produced by the oxidation of HO. But the formation mechanism of 4-tert-butylcatechol in the two processes was different. The benzene ring was fractured in 4-t-BP oxidation process and 29% of TOC was degraded after 16h irradiation.
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Affiliation(s)
- Yanlin Wu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jin Shi
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Hongche Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Jianfu Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Wenbo Dong
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China.
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Upregulation of MiR-196a promotes cell proliferation by downregulating p27 kip1 in laryngeal cancer. Biol Res 2016; 49:40. [PMID: 27678369 PMCID: PMC5039793 DOI: 10.1186/s40659-016-0100-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 09/22/2016] [Indexed: 12/21/2022] Open
Abstract
Background Accumulating evidence has confirmed that miR-196a plays a critical role in tumorigenesis and tumor progression in a variety of cancers. It has been demonstrated that miR-196a is highly up-regulated in laryngeal cancer by miRNA profiling analysis. However, the functional mechanism of miR-196a in laryngeal cancer remains unclear. This study aims to explore the mechanism of miR-196a in laryngeal cancer. Methods In the present study, we conducted qPCR analysis of miR-196a expression in human laryngeal cancer and showed that miR-196a was overexpressed in tumor-derived samples and laryngeal cancer cell lines compared with matched normal controls. Further functional analysis of miR-196a demonstrated that the inhibition of miR-196a could inhibit laryngeal cell-cycle progression and proliferation in vitro. Luciferase reporter assay and western blot confirmed that miR-196a directly targeted p27kip1. Moreover, in order to investigate whether miR-196a regulated cell growth in laryngeal cancer cells by targeting p27kip1, rescue studies were performed in laryngeal cancer cells. Results Results showed that overexpression of p27kip1 rescue decreased cell proliferation caused by miR-196a inhibitors. A negative relation between miR-196a and p27kip1 expression in laryngeal cancer tissues were also noted by further analyses. Conclusions The present study showed that miR-196a was upregulated in laryngeal cancer and promoted cell proliferation by downregulating p27kip1 in laryngeal cancer. However, further studies are needed to verify this finding.
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Lee CS, Joo YH, Baek HS, Park M, Kim JH, Shin HJ, Park NH, Lee JH, Park YH, Shin SS, Lee HK. Different effects of five depigmentary compounds, rhododendrol, raspberry ketone, monobenzone, rucinol and AP736 on melanogenesis and viability of human epidermal melanocytes. Exp Dermatol 2015; 25:44-9. [PMID: 26440747 DOI: 10.1111/exd.12871] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2015] [Indexed: 12/13/2022]
Abstract
Numerous medications are used to treat hyperpigmentation. However, several reports have indicated that repeated application of some agents, such as rhododendrol (RD), raspberry ketone (RK) and monobenzone (MB), can be toxic to melanocytes. Although these agents had severe side effects in human trials, no current in vitro methods can predict the safety of such drugs. This study assessed the in vitro effects of five depigmentary compounds including leukoderma-inducing agents. In particular, we determined the effects of different concentrations and exposure times of different depigmentary agents on cell viability and melanogenesis in the presence and absence of ultraviolet B (UVB) radiation. Concentrations of RD, RK and MB that inhibit melanogenesis are similar to concentrations that are cytotoxic; however, concentrations of rucinol (RC) and AP736 that inhibit melanogenesis are much lower than concentrations that are cytotoxic. Furthermore, the concentrations that cause toxic effects depend on exposure duration, and prolonged exposure to RD, RK and MB had more cytotoxic effects than prolonged exposure to RC and AP736. The cytotoxic effects of RD and RK appear to be mediated by apoptosis due to increased expression of caspase-3 and caspase-8; UVB radiation increased the cytotoxicity of these agents and also increased caspase activity. Our results indicate that different leukoderma-inducing compounds have different effects on the viability of normal epidermal melanocytes and suggest that the in vitro assay used here can be used to predict whether an investigational compound that induces leukoderma may lead to adverse effects in human trials.
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Okura M, Yamashita T, Ishii-Osai Y, Yoshikawa M, Sumikawa Y, Wakamatsu K, Ito S. Effects of rhododendrol and its metabolic products on melanocytic cell growth. J Dermatol Sci 2015; 80:142-9. [DOI: 10.1016/j.jdermsci.2015.07.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 06/10/2015] [Accepted: 07/21/2015] [Indexed: 11/26/2022]
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A convenient screening method to differentiate phenolic skin whitening tyrosinase inhibitors from leukoderma-inducing phenols. J Dermatol Sci 2015; 80:18-24. [PMID: 26228294 DOI: 10.1016/j.jdermsci.2015.07.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/01/2015] [Accepted: 07/16/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Tyrosinase is able to oxidize a great number of phenols and catechols to form ortho-quinones. Ortho-quinones are highly reactive compounds that exert cytotoxicity through binding with thiol enzymes and the production of reactive oxygen species. Certain phenolic (and catecholic) compounds are known to induce contact/occupational leukoderma through activation to ortho-quinones. OBJECTIVE We report a convenient screening method to follow the oxidation of those leukoderma-inducing phenols by mushroom tyrosinase. METHODS Oxidation of phenolic compounds by mushroom tyrosinase was followed periodically by UV-vis spectrophotometry. The production of ortho-quinones were confirmed by their absorptions around 400-420 nm. HPLC analysis after reduction with NaBH4 detected the corresponding catechols. RESULTS Leukoderma-inducing phenols, rhododendrol, raspberry ketone, 4-methoxyphenol, 4-benzyloxyphenol, 4-tert-butylphenol, and 4-tert-butylcatechol, were readily oxidized by mushroom tyrosinase to form ortho-quinones. On the other hand, phenolic skin whitening tyrosinase inhibitors, ellagic acid, 4-n-butylresorcinol, potassium 4-methoxysalicylate, and 2,2'-dihydroxy-5,5'-di-n-propylbiphenyl, were not oxidized by mushroom tyrosinase, while arbutin was only slowly oxidized. CONCLUSION This study has provided a convenient screening method to differentiate phenolic skin whitening tyrosinase inhibitors from leukoderma-inducing phenols. A common chemical feature of the latter group of compounds is that they are readily oxidized by tyrosinase to form reactive ortho-quinone species. The present results point out the necessity that tyrosinase inhibitors should also be examined as substrates if they are phenolic compounds.
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Abstract
Vitiligo is an acquired depigmenting disorder that affects 0.5% to 2% of the world population. Three different forms are classified according to the distribution of lesions; namely non-segmental, segmental and mixed vitiligo. Vitiligo is associated with polymorphisms in genes involved in the immune response and in melanogenesis. However, environmental factors are required for the development of manifest disease. In general, the diagnosis is clinical and no laboratory tests or biopsies are required. Metabolic alterations are central to current concepts in pathophysiology. They induce an increased generation of reactive oxygen species and susceptibility to mild exogenous stimuli in the epidermis. This produces a senescent phenotype of skin cells, leads to the release of innate immune molecules, which trigger autoimmunity, and ultimately causes dysfunction and death of melanocytes. Clinical management aims to halt depigmentation, and to either repigment or depigment the skin, depending on the extent of disease. New therapeutic approaches include stimulation of melanocyte differentiation and proliferation through α-melanocyte-stimulating hormone analogues and through epidermal stem cell engineering. Several questions remain unsolved, including the connection between melanocyte depletion and stem cell exhaustion, the underlying degenerative mechanisms and the biological mediators of cell death. Overall, vitiligo is an excellent model for studying degenerative and autoimmune processes and for testing novel approaches in regenerative medicine. For an illustrated summary of this Primer, visit: http://go.nature.com/vIhFSC.
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Affiliation(s)
- Mauro Picardo
- Cutaneous Physiopathology, San Gallicano Dermatologic Institute, IFO IRCCS, via Elio Chianesi 53, 00144 Rome, Italy
| | - Maria L Dell'Anna
- Cutaneous Physiopathology, San Gallicano Dermatologic Institute, IFO IRCCS, via Elio Chianesi 53, 00144 Rome, Italy
| | - Khaled Ezzedine
- Service de Dermatologie et Dermatologie Pédiatrique, Centre de référence pour les maladies rares de la peau, INSERM 1035, Université de Bordeaux, Bordeaux, France
| | - Iltefat Hamzavi
- Multicultural Dermatology Center, Department of Dermatology, Henry Ford Hospital Detroit, Michigan, USA
| | - John E Harris
- Division of Dermatology, Department of Medicine, University of Massachusetts Medical School, Worcester, USA
| | | | - Alain Taieb
- Service de Dermatologie et Dermatologie Pédiatrique, Centre de référence pour les maladies rares de la peau, INSERM 1035, Université de Bordeaux, Bordeaux, France
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Sun J, Feng X, Gao S, Xiao Z. microRNA-338-3p functions as a tumor suppressor in human non‑small‑cell lung carcinoma and targets Ras-related protein 14. Mol Med Rep 2014; 11:1400-6. [PMID: 25374067 DOI: 10.3892/mmr.2014.2880] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 05/28/2014] [Indexed: 11/06/2022] Open
Abstract
microRNAs (miRNAs) have been demonstrated to be important gene regulators with critical roles in diverse biological processes, including tumorigenesis. Accumulating evidence suggests that miR‑338-3p exerts a tumor suppressor role and is downregulated in tumors, including gastric cancer and colorectal carcinoma. However, the role of miR‑338-3p in lung cancer, particularly non‑small‑cell lung carcinoma (NSCLC), has remained elusive. In the present study, the expression levels of miR‑338-3p in NSCLC tissues were compared with those of matched normal tissues by use of polymerase chain reaction analysis. miR-338-3p was shown to be downregulated in NSCLC tissues, and the expression levels of miR‑338‑3p were significantly correlated with NSCLC cancer differentiation, pathological stage and lymph‑node metastasis. Ectopic miR-338-3p expression significantly suppressed the in vitro proliferation and colony formation of NSCLC cells and enhanced apoptosis. Of note, ectopic miR‑338-3p expression significantly inhibited Ras‑related protein 14 (RAB14) mRNA and protein expression, and reduced luciferase reporter activity containing the RAB14 3'-untranslated region through the first binding site. These findings suggested that miR‑338-3p regulated the survival of NSCLC cells partially through the downregulation of RAB14. Therefore, targeting the miR‑338-3p/RAB14 interaction may serve as a novel therapeutic application to treat NSCLC patients.
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Affiliation(s)
- Jiangtao Sun
- Institute of Cancer Research, The First Affiliated Hospital of Henan University of Science Technology, Luoyang, Henan 471003, P.R. China
| | - Xiaoshang Feng
- Institute of Cancer Research, The First Affiliated Hospital of Henan University of Science Technology, Luoyang, Henan 471003, P.R. China
| | - Shegan Gao
- Institute of Cancer Research, The First Affiliated Hospital of Henan University of Science Technology, Luoyang, Henan 471003, P.R. China
| | - Zhongyue Xiao
- Institute of Cancer Research, The First Affiliated Hospital of Henan University of Science Technology, Luoyang, Henan 471003, P.R. China
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Kasamatsu S, Hachiya A, Nakamura S, Yasuda Y, Fujimori T, Takano K, Moriwaki S, Hase T, Suzuki T, Matsunaga K. Depigmentation caused by application of the active brightening material, rhododendrol, is related to tyrosinase activity at a certain threshold. J Dermatol Sci 2014; 76:16-24. [PMID: 25082450 DOI: 10.1016/j.jdermsci.2014.07.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/03/2014] [Accepted: 07/03/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Tyrosinase, the rate-limiting enzyme required for melanin production, has been targeted to develop active brightening/lightening materials for skin products. Unexpected depigmentation of the skin characterized with the diverse symptoms was reported in some subjects who used a tyrosinase-competitive inhibiting quasi-drug, rhododendrol. OBJECTIVE To investigate the mechanism underlying the depigmentation caused by rhododendrol-containing cosmetics, this study was performed. METHODS The mechanism above was examined using more than dozen of melanocytes derived from donors of different ethnic backgrounds. The RNAi technology was utilized to confirm the effect of tyrosinase to induce the cytotoxicity of rhododendrol and liquid chromatography-tandem mass spectrometry was introduced to detect rhododendrol and its metabolites in the presence of tyrosinase. RESULTS Melanocyte damage was related to tyrosinase activity at a certain threshold. Treatment with a tyrosinase-specific siRNA was shown to dramatically rescue the rhododendrol-induced melanocyte impairment. Hydroxyl-rhododendrol was detected only in melanocytes with higher tyrosinase activity. When an equivalent amount of hydroxyl-rhododendrol was administered, cell viability was almost equally suppressed even in melanocytes with lower tyrosinase activity. CONCLUSION The generation of a tyrosinase-catalyzed hydroxyl-metabolite is one of the causes for the diminishment of the melanocyte viability by rhododendrol.
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Affiliation(s)
- Shinya Kasamatsu
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Akira Hachiya
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan.
| | - Shun Nakamura
- Analytical Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Yuka Yasuda
- Analytical Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Taketoshi Fujimori
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Kei Takano
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Shigeru Moriwaki
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Tadashi Hase
- Biological Science Laboratories, Kao Corporation, Haga 321-3497, Tochigi, Japan
| | - Tamio Suzuki
- Department of Dermatology, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Kayoko Matsunaga
- Department of Dermatology, Fujita Health University School of Medicine, 1-98, Dengakugakubo, Kutsukake-cho, Toyoake 470-1192, Aichi, Japan
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Webb KC, Eby JM, Hariharan V, Hernandez C, Luiten RM, Le Poole IC. Enhanced bleaching treatment: opportunities for immune-assisted melanocyte suicide in vitiligo. Exp Dermatol 2014; 23:529-33. [PMID: 24840876 DOI: 10.1111/exd.12449] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2014] [Indexed: 01/13/2023]
Abstract
Depigmentation in vitiligo occurs by progressive loss of melanocytes from the basal layer of the skin, and can be psychologically devastating to patients. T cell-mediated autoimmunity explains the progressive nature of this disease. Rather than being confronted with periods of rapid depigmentation and bouts of repigmentation, patients with long-standing, treatment-resistant vitiligo can undergo depigmentation treatment. The objective is to remove residual pigmentation to achieve a cosmetically acceptable result--that of skin with a uniform appearance. In the United States, only the use of mono-benzyl ether of hydroquinone (MBEH) is approved for this purpose. However, satisfactory results can take time to appear, and there is a risk of repigmentation. MBEH induces necrotic melanocyte death followed by a cytotoxic T-cell response to remaining, distant melanocytes. As cytotoxic T-cell responses are instrumental to depigmentation, we propose that combining MBEH with immune adjuvant therapies will accelerate immune-mediated melanocyte destruction to achieve faster, more definitive depigmentation than with MBEH alone. As Toll-like Receptor (TLR) agonists--imiquimod, CpG, and Heat Shock Protein 70 (HSP 70)--all support powerful Th1 responses, we propose that using MBEH in combination with these agents can achieve superior depigmentation results for vitiligo patients.
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Affiliation(s)
- Kirsten C Webb
- Department of Dermatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Sasaki M, Kondo M, Sato K, Umeda M, Kawabata K, Takahashi Y, Suzuki T, Matsunaga K, Inoue S. Rhododendrol, a depigmentation-inducing phenolic compound, exerts melanocyte cytotoxicity via a tyrosinase-dependent mechanism. Pigment Cell Melanoma Res 2014; 27:754-63. [PMID: 24890809 DOI: 10.1111/pcmr.12269] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/23/2014] [Indexed: 11/28/2022]
Abstract
Rhododendrol, an inhibitor of melanin synthesis developed for lightening/whitening cosmetics, was recently reported to induce a depigmentary disorder principally at the sites of repeated chemical contact. Rhododendrol competitively inhibited mushroom tyrosinase and served as a good substrate, while it also showed cytotoxicity against cultured human melanocytes at high concentrations sufficient for inhibiting tyrosinase. The cytotoxicity was abolished by phenylthiourea, a chelator of the copper ions at the active site, and by specific knockdown of tyrosinase with siRNA. Hence, the cytotoxicity appeared to be triggered by the enzymatic conversion of rhododendrol to active product(s). No reactive oxygen species were detected in the treated melanocytes, but up-regulation of the CCAAT-enhancer-binding protein homologous protein gene responsible for apoptosis and/or autophagy and caspase-3 activation were found to be tyrosinase dependent. These results suggest that a tyrosinase-dependent accumulation of ER stress and/or activation of the apoptotic pathway may contribute to the melanocyte cytotoxicity.
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Affiliation(s)
- Minoru Sasaki
- Innovative Beauty Science Laboratory, Kanebo Cosmetics Inc., Kanagawa, Japan
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Jeon IK, Park CJ, Lee MH, Lee DY, Kang HY, Hann SK, Choi GS, Lee HJ, Kim TH, Lee AY, Oh SH. A Multicenter Collaborative Study by the Korean Society of Vitiligo about Patients' Occupations and the Provoking Factors of Vitiligo. Ann Dermatol 2014; 26:349-56. [PMID: 24966635 PMCID: PMC4069646 DOI: 10.5021/ad.2014.26.3.349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 05/28/2013] [Accepted: 07/12/2013] [Indexed: 11/18/2022] Open
Abstract
Background It was previously thought that persons with genetic predispositions to vitiligo develop the condition after exposure to various precipitating environmental factors. However, in many cases, the aggravating factors of vitiligo have not been clearly identified. Objective To identify the aggravating factors of vitiligo in the working environment and daily life. Methods A total of 489 vitiligo patients were recruited from 10 institutions in South Korea; patients were provided with a questionnaire about environmental factors and behavior patterns in the workplace and in daily life, and their association with vitiligo. Results Ninety-five of the 470 enrolled patients (20.2%) answered that environmental risk factors in daily life and in the workplace affected the development of vitiligo. The most frequently attributed causes were trauma and burn (13.6%), followed by sunlight (12.8%), stress (12.8%), cleaning products/disinfectant/chemicals (4.9%), and hair dye (2.1%). Conclusion Vitiligo of the hand and foot was associated with frequent exposure to aggravating materials and overexposure to sunlight, along with frequent trauma of these areas, all of which could be considered important risk factors of vitiligo. The development of vitiligo could potentially be controlled through the early detection of aggravating factors.
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Affiliation(s)
- In Kyung Jeon
- Department of Dermatology, Gangnam Severance Hospital, Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Chul Jong Park
- Department of Dermatology, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea
| | - Mu-Hyoung Lee
- Department of Dermatology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Dong Youn Lee
- Department of Dermatology, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hee Young Kang
- Department of Dermatology, Ajou University School of Medicine, Suwon, Korea
| | - Seung Kyung Hann
- Korea Institute of Vitiligo Research & Drs. Woo and Hann's Skin Center, Seoul, Korea
| | - Gwang Seong Choi
- Department of Dermatology, Inha University School of Medicine, Incheon, Korea
| | - Hee Jung Lee
- Department of Dermatology, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | | | - Ai-Young Lee
- Department of Dermatology, Dongguk University Ilsan Hospital, Dongguk University Graduate School of Medicine, Goyang, Korea
| | - Sang Ho Oh
- Department of Dermatology, Severance Hospital, Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea
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Vrijman C, Hosseinpour D, Bakker JG, Wolkerstorfer A, Bos JD, van der Veen JPW, Luiten RM. Provoking factors, including chemicals, in Dutch patients with vitiligo. Br J Dermatol 2013; 168:1003-11. [PMID: 23252956 DOI: 10.1111/bjd.12162] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND In vitiligo, many provoking factors have been described, but epidemiological data, especially on the role of contact with chemicals, are scarce. OBJECTIVE To obtain an insight into the patient-reported factors provoking vitiligo, including contact with chemicals. METHODS A retrospective cohort study was conducted on all 1264 patients with vitiligo who visited the Netherlands Institute for Pigment disorders from January 2003 to December 2007. Patients for whom an exogenous provoking factor was recorded were sent a questionnaire. Subsequently, patients who mentioned a chemical provoking factor were contacted to elucidate the alleged causal relationship between exposure to the chemical and the onset of vitiligo. RESULTS A total of 300 out of the 1264 patients indicated that provoking factors had played a role in their disease. Two hundred and forty-six patients were sent a questionnaire, which was returned by 177 (response rate of 72%). Emotional stress was indicated as a provoking factor in 98 patients (55.4%), 51 patients (28.8%) recorded sunburn, 34 patients (19.2%) recorded mechanical factors and 20 patients (11.3%) other factors. Of 29 patients (16.4%) who indicated a chemical factor, a presumed causal relationship could be corroborated in four. The chemicals involved were para-tertiary butylphenol (n = 2), captan (n = 1) and diphencyprone (n = 1). CONCLUSION The majority of the patients with vitiligo from this study did not mention provoking factors, but the ones who did point to emotional stress in more than half of the cases. Of the 29 patients who assigned chemical provoking factors, solvents were mainly indicated. However, a presumed relationship with the chemical could be corroborated in only four patients.
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Affiliation(s)
- C Vrijman
- Department of Dermatology and The Netherlands Institute for Pigment Disorders (SNIP), Academic Medical Centre, University of Amsterdam, Amsterdam NL-1105AZ, the Netherlands.
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Zhang Y, Liu L, Jin L, Yi X, Dang E, Yang Y, Li C, Gao T. Oxidative stress-induced calreticulin expression and translocation: new insights into the destruction of melanocytes. J Invest Dermatol 2013; 134:183-191. [PMID: 23771121 DOI: 10.1038/jid.2013.268] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 12/21/2022]
Abstract
Increased reactive oxygen species (ROS) contribute to melanocyte apoptosis and the development of cutaneous diseases or disorders via autoimmunity. However, the mechanisms and interrelationships between ROS and autoimmunity are unknown. This study aimed to investigate the role of calreticulin (CRT) in hydrogen peroxide (H2O2)-induced apoptosis in melanocytes. Total CRT levels increased in a time-dependent manner in human immortalized normal and vitiligo melanocytes exposed to H2O2-induced oxidative stress, and surface levels of CRT were increased. Moreover, CRT overexpression increased H2O2-induced apoptosis, whereas knockdown showed the opposite results. Furthermore, CRT-treated peripheral blood mononuclear cells (PBMCs) or stressed melanocytes expressed higher levels of IL-6 and tumor necrosis factor-α (TNF-α) than untreated cells (P<0.05); this effect was inhibited with CRT knockdown. In an in vivo model, CRT levels were positively correlated with lesion area (R=0.7582, P<0.0001) and duration of vitiligo in patients (P<0.001). ELISA analyses revealed that CRT expression was higher in vitiligo patients as compared with healthy subjects (P<0.05). These data demonstrate that CRT exposure via H2O2-induced oxidative stress plays a significant role in melanocyte apoptosis and suggest a relationship between apoptosis and immune reactions during melanocyte destruction.
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Affiliation(s)
- Yajun Zhang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ling Liu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
| | - Liang Jin
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiuli Yi
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Erle Dang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yang Yang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Chunying Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
| | - Tianwen Gao
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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Muñoz-Muñoz JL, García-Molina MDM, García-Molina F, Varon R, García-Ruiz PA, Rodríguez-López JN, García-Cánovas F. Indirect inactivation of tyrosinase in its action on 4-tert-butylphenol. J Enzyme Inhib Med Chem 2013; 29:344-52. [PMID: 23578311 DOI: 10.3109/14756366.2013.782298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Under anaerobic conditions, the o-diphenol 4-tert-butylcatechol (TBC) irreversibly inactivates met and deoxytyrosinase enzymatic forms of tyrosinase. However, the monophenol 4-tert-butylphenol (TBF) protects the enzyme from this inactivation. Under aerobic conditions, the enzyme suffers suicide inactivation when it acts on TBC. We suggest that TBF does not directly cause the suicide inactivation of the enzyme in the hydroxylase activity, but that the o-diphenol, which is necessary for the system to reach the steady state, is responsible for the process. Therefore, monophenols do not induce the suicide inactivation of tyrosinase in its hydroxylase activity, and there is a great difference between the monophenols that give rise to unstable o-quinones such as L-tyrosine, which rapidly accumulate L-dopa in the medium and those like TBF, after oxidation, give rise to a very stable o-quinone.
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Affiliation(s)
- Jose Luis Muñoz-Muñoz
- GENZ: Grupo de Investigación Enzimología, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, Universidad de Murcia , Espinardo, Murcia , Spain
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Ogata Y, Toyama T, Yu N, Wang X, Sei K, Ike M. Occurrence of 4-tert-butylphenol (4-t-BP) biodegradation in an aquatic sample caused by the presence of Spirodela polyrrhiza and isolation of a 4-t-BP-utilizing bacterium. Biodegradation 2012; 24:191-202. [DOI: 10.1007/s10532-012-9570-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 06/26/2012] [Indexed: 12/01/2022]
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Feng B, Wang R, Chen LB. MiR-100 resensitizes docetaxel-resistant human lung adenocarcinoma cells (SPC-A1) to docetaxel by targeting Plk1. Cancer Lett 2012; 317:184-91. [PMID: 22120675 DOI: 10.1016/j.canlet.2011.11.024] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/21/2011] [Accepted: 11/18/2011] [Indexed: 12/14/2022]
Abstract
MicroRNAs (miRNAs) expression correlates with biological characteristics of both normal cells and cancer cells, but their roles in cancer chemoresistance remain unclear. By microarray analysis, miR-100 was found significantly down-regulated in docetaxel-resistant SPC-A1/DTX cells compared with parental SPC-A1 cells. Ectopic miR-100 expression resensitized SPC-A1/DTX cells to docetaxel by suppression of cell proliferation and induction of cell arrest in G(2)/M phase and apoptosis. Knock-down of Plk1, which was a direct target of miR-100, yielded similar effects as that of ectopic miR-100 expression. The inverse correlation between miR-100 and Plk1 expression was also detected in nude mice SPC-A1/DTX tumor xenografts and clinical lung adenocarcinoma tissues and was proved to be related with the in vivo response to docetaxel. Thus, our results suggested that down-regulation of miR-100 could lead to Plk1 over-expression and eventually to docetaxel chemoresistance of human lung adenocarcinoma.
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Affiliation(s)
- Bing Feng
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, PR China
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Sun M, Liu XH, Li JH, Yang JS, Zhang EB, Yin DD, Liu ZL, Zhou J, Ding Y, Li SQ, Wang ZX, Cao XF, De W. MiR-196a is upregulated in gastric cancer and promotes cell proliferation by downregulating p27(kip1). Mol Cancer Ther 2012; 11:842-52. [PMID: 22343731 DOI: 10.1158/1535-7163.mct-11-1015] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aberrant expression of miR-196a has been frequently reported in cancer studies. However, the expression and mechanism of its function in gastric cancer remains unclear. Quantitative real-time PCR was carried out to detect the relative expression of miR-196a in gastric cancer cell lines and tissues. SGC7901 cells were treated with miR-196a inhibitors, mimics, or pCDNA/miR-196a to investigate the role of miR-196a in cell proliferation. Higher expression of miR-196a in gastric cancer tissues was associated with tumor size, a higher clinical stage, and was also correlated with shorter overall survival of patients with gastric cancer. Exogenous downregulation of miR-196a expression significantly suppressed the in vitro cell-cycle progression, proliferation, and colony formation of gastric cancer cells, and ectopic miR-196a expression significantly enhanced the development of tumors in nude mice. Luciferase assays revealed that miR-196a inhibited p27(kip1) expression by targeting one binding site in the 3'-untranslated region (3'-UTR) of p27(kip1) mRNA. qPCR and Western blot assays verified that miR-196a reduced p27(kip1) expression at both mRNA and protein levels. The p27(kip1)-mediated repression in cell proliferation was reverted by exogenous miR-196a expression. A reverse correlation between miR-196a and p27(kip1) expression was noted in gastric cancer tissues. Our study shows that aberrant overexpression of miR-196a and consequent downregulation of p27(kip1) could contribute to gastric carcinogenesis and would be targets for gastric cancer therapies and further developed as potential prognostic factors.
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Affiliation(s)
- Ming Sun
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China
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Li J, Guo Y, Liang X, Sun M, Wang G, De W, Wu W. MicroRNA-223 functions as an oncogene in human gastric cancer by targeting FBXW7/hCdc4. J Cancer Res Clin Oncol 2012; 138:763-74. [PMID: 22270966 DOI: 10.1007/s00432-012-1154-x] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/06/2012] [Indexed: 12/26/2022]
Abstract
AIMS The aim of this study was (a) to determine the role of micro-223 (miR-223) in gastric cancer and (b) to elucidate its regulatory mechanism on the FBXW7/hCdc4 gene. MATERIALS AND METHODS Artificial miR-223 and control oligonucleotide was transfected into gastric cancer cell line SGC7901 by using Lipofectamine2000. Apoptosis of miR-223 group and control group cells was analyzed by flow cytometry, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and colony formation assays were performed to detect the cell viability, to survey migration of miR-223 group and control group cells; scratch wound-healing motility assays, Transwell Assay, and Western blot test were performed to measure the variance of hFBXW7. Luciferase Reporter Assay, which was done by pLUC-hFBXW7 WT-3'-UTR co-transfected with pLMP-hsa-miR-223 or pLMP plasmid (as control) into HEK293T cells, used to detect whether hFBXW7 is a direct target gene of miR-223. Gastric cancer cell line SGC7901 transfected with miR-223 or control oligonucleotide was resuspended in ECM gel and then was injected into the flank of nude mice, 4 weeks later, the nude mice were euthanized. The tumors were excised then were measured and weighted. SYBR-Green I-based real-time RT-PCR study was used to detect the level of miR-223 in 22 gastric cancer tissue and corresponding gastric mucosa tissues. Immunohistochemical method was applied to detect the protein of hFBXW7. RESULTS Gastric cancer cell line SGC7901, transfected with miR-223, showed significant reduction in cellular apoptosis and increased proliferation and invasion in vitro. Similar results were found in tumorigenesis assays performed in nude mice. Moreover, 19 of 22 cancer tissue samples highly expressed miR-223, when compared with patient-matched normal gastric mucosa. Specifically, patients with lymph node metastasis or metastatic disease (M1) at an advanced pathological stage showed significantly higher expression of miR-223. FBXW7/hCdc4 protein (FBW7) levels in gastric cancer cases were inversely correlated with miR-223 expression. Overexpression of miR-223 in gastric cancer cell lines decreased FBW7 expression at the translational level and decreased FBXW7/hCdc4-driven luciferase-reporter activity. CONCLUSION In summary, the data indicated that miR-223 targets FBXW7/hCdc4 expression at the post-transcriptional level and appears to regulate cellular apoptosis, proliferation, and invasion in gastric cancer. MiR-223 may serve as a novel therapeutic target in gastric cancer.
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Affiliation(s)
- Jinhai Li
- Department of Gastrointestinal Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
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Feng B, Wang R, Song HZ, Chen LB. MicroRNA-200b reverses chemoresistance of docetaxel-resistant human lung adenocarcinoma cells by targeting E2F3. Cancer 2011; 118:3365-76. [PMID: 22139708 DOI: 10.1002/cncr.26560] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/26/2011] [Accepted: 08/15/2011] [Indexed: 12/22/2022]
Abstract
BACKGROUND MicroRNAs (miRNAs) have been identified as important posttranscriptional regulators involved in various biological and pathological processes of cells, but their association with tumor chemoresistance has not been fully understood. METHODS We detected miRNA-200b (miR-200b) expression in different lung adenocarcinoma cell lines and then focused on its roles in regulation of docetaxel chemoresistance. We also identified E2F3 as a novel target of miR-200b. RESULTS Based on miRNA microarray data, miR-200b was identified as the most down-regulated miRNA in docetaxel-resistant SPC-A1/DTX cells compared with parental SPC-A1 cells. Ectopic miR-200b expression reversed docetaxel chemoresistance of lung adenocarcinoma cells through cell proliferation inhibition, apoptosis enhancement, and G(2) /M cell cycle arrest. In a nude mouse xenograft model, up-regulation of miR-200b significantly enhanced response of SPC-A1/DTX cells to docetaxel. Luciferase reporters containing the 3' untranslated region sequence of E2F3 messenger RNA were used to demonstrate that miR-200b could directly target E2F3. Small interfering RNA-mediated E2F3 knockdown revealed similar effects as that of ectopic miR-200b expression. Decreased miR-200b expression was also detected in tumor tissues sampled from lung adenocarcinoma patients treated with docetaxel-based chemotherapy and was proved to be correlated with high expression of E2F3, decreased sensitivity to docetaxel, and poor prognosis. CONCLUSIONS Our results suggest that down-regulation of miR-200b could lead to E2F3 overexpression and in turn contribute to chemoresistance of lung adenocarcinoma cells to docetaxel.
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Affiliation(s)
- Bing Feng
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
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Bajaj AK, Saraswat A, Srivastav PK. Chemical leucoderma: Indian scenario, prognosis, and treatment. Indian J Dermatol 2011; 55:250-4. [PMID: 21063517 PMCID: PMC2965911 DOI: 10.4103/0019-5154.70674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Chemical leucoderma is an industrial disorder in developed countries and the common causative chemicals are phenols and catechols. Due to stringent controls and preventive measures the incidence has come down. In the recent past various chemicals in consumer products have also been documented to produce depigmentation. In India due to lax quality control measures chemical leucoderma due to consumer items is not uncommon.The various consumer items documented to cause contact depigmentation are sticker bindis, rain shoes, plastic chappals, hair dye/ black henna(kali mehndi), alta, wallets and even mobile plastic covers.
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Abstract
Vitiligo is a disorder that causes the destruction of melanocytes. It has three important factors underlying this destruction. The depigmented skin has many aberrant functions such as a muted response to contact allergens, a phenomenon also seen in mice that depigment. The white skin of those with vitiligo does not form non-melanoma skin cancers although the white skin of albinos, which has a similar color as vitiligo, is highly susceptible to skin cancer.
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Affiliation(s)
- James J Nordlund
- Department of Dermatology, Wright State Boonshoft School of Medicine, Dayton, Ohio, USA.
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37
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Beruflich bedingte Leukoderme und Vitiligo. Hautarzt 2011; 62:209-14. [DOI: 10.1007/s00105-010-2126-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wang R, Wang ZX, Yang JS, Pan X, De W, Chen LB. MicroRNA-451 functions as a tumor suppressor in human non-small cell lung cancer by targeting ras-related protein 14 (RAB14). Oncogene 2011; 30:2644-58. [PMID: 21358675 DOI: 10.1038/onc.2010.642] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Accumulating evidence suggests that microRNAs (miRNAs) are important gene regulators, which can have critical roles in diverse biological processes including tumorigenesis. In this study, we analyzed the miRNA expression profiles in non-small cell lung carcinoma (NSCLC) by use of a miRNA microarray platform and identified 40 differentially expressed miRNAs. We showed that miRNA (miR)-451 was the most downregulated in NSCLC tissues. The expression level of miR-451 was found to be significantly correlated with tumor differentiation, pathological stage and lymph-node metastasis. Moreover, low miR-451 expression level was also correlated with shorter overall survival of NSCLC patients (P<0.001). Ectopic miR-451 expression significantly suppressed the in vitro proliferation and colony formation of NSCLC cells and the development of tumors in nude mice by enhancing apoptosis, which might be associated with inactivation of Akt signaling pathway. Interestingly, ectopic miR-451 expression could significantly inhibit RAB14 protein expression and decrease a luciferase-reporter activity containing the RAB14 3'-untranslated region (UTR). In addition,, RNA interference silencing of RAB14 gene could recapitulate the tumor suppressor function of miR-451, whereas restoration of RAB14 expression could partially attenuate the tumor suppressor function of miR-451 in NSCLC cells. Furthermore, we also showed that strong positive immunoreactivity of RAB14 protein was significantly associated with downregulation of miR-451 (P=0.01). These findings suggest that miR-451 regulates survival of NSCLC cells partially through the downregulation of RAB14. Therefore, targeting with the miR-451/RAB14 interaction might serve as a novel therapeutic application to treat NSCLC patients.
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Affiliation(s)
- R Wang
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu, PR China
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Toyama T, Momotani N, Ogata Y, Miyamori Y, Inoue D, Sei K, Mori K, Kikuchi S, Ike M. Isolation and characterization of 4-tert-butylphenol-utilizing Sphingobium fuliginis strains from Phragmites australis rhizosphere sediment. Appl Environ Microbiol 2010; 76:6733-40. [PMID: 20802076 PMCID: PMC2953011 DOI: 10.1128/aem.00258-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 08/17/2010] [Indexed: 11/20/2022] Open
Abstract
We isolated three Sphingobium fuliginis strains from Phragmites australis rhizosphere sediment that were capable of utilizing 4-tert-butylphenol as a sole carbon and energy source. These strains are the first 4-tert-butylphenol-utilizing bacteria. The strain designated TIK-1 completely degraded 1.0 mM 4-tert-butylphenol in basal salts medium within 12 h, with concomitant cell growth. We identified 4-tert-butylcatechol and 3,3-dimethyl-2-butanone as internal metabolites by gas chromatography-mass spectrometry. When 3-fluorocatechol was used as an inactivator of meta-cleavage enzymes, strain TIK-1 could not degrade 4-tert-butylcatechol and 3,3-dimethyl-2-butanone was not detected. We concluded that metabolism of 4-tert-butylphenol by strain TIK-1 is initiated by hydroxylation to 4-tert-butylcatechol, followed by a meta-cleavage pathway. Growth experiments with 20 other alkylphenols showed that 4-isopropylphenol, 4-sec-butylphenol, and 4-tert-pentylphenol, which have alkyl side chains of three to five carbon atoms with α-quaternary or α-tertiary carbons, supported cell growth but that 4-n-alkylphenols, 4-tert-octylphenol, technical nonylphenol, 2-alkylphenols, and 3-alkylphenols did not. The rate of growth on 4-tert-butylphenol was much higher than that of growth on the other alkylphenols. Degradation experiments with various alkylphenols showed that strain TIK-1 cells grown on 4-tert-butylphenol could degrade 4-alkylphenols with variously sized and branched side chains (ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, and branched nonyl) via a meta-cleavage pathway but not 2- or 3-alkylphenols. Along with the degradation of these alkylphenols, we detected methyl alkyl ketones that retained the structure of the original alkyl side chains. Strain TIK-1 may be useful in the bioremediation of environments polluted by 4-tert-butylphenol and various other 4-alkylphenols.
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Affiliation(s)
- Tadashi Toyama
- Department of Research, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
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Monobenzyl ether of hydroquinone and 4-tertiary butyl phenol activate markedly different physiological responses in melanocytes: relevance to skin depigmentation. J Invest Dermatol 2010; 130:211-20. [PMID: 19657355 DOI: 10.1038/jid.2009.214] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Monobenzyl ether of hydroquinone (MBEH) is a Food and Drug Administration approved drug used for depigmentation therapy of advanced vitiligo. Here, the working mechanism of MBEH is explored in comparison to 4-tertiary butyl phenol (4-TBP), a known causative agent for occupational vitiligo mediating apoptotic melanocytic death. Cytotoxic experiments reveal that similar to 4-TBP, MBEH induces specific melanocyte death. To compare death pathways initiated by 4-TBP and MBEH, classical apoptotic hallmarks were evaluated in treated melanocytes. MBEH induced cell death without activating the caspase cascade or DNA fragmentation, showing that the death pathway is non-apoptotic. Release of High Mobility Group Box-1 protein by MBEH-treated melanocytes and ultrastructural features further confirmed a necrotic death pathway mediated by MBEH. A negative correlation between MBEH-induced cell death and cellular melanin content supports a cytoprotective role for melanin. Moreover, MBEH exposure upregulated the levels of melanogenic enzymes in cultured melanocytes and skin explants, whereas 4-TBP reduced the expression of the same. In summary, exposure to MBEH or 4-TBP has profoundly different consequences for melanocyte physiology and activates different death pathways. As the mode of cell death defines the nature of the immune response that follows, these findings help to explain the relative efficacy of these agents in mediating depigmentation.
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Abstract
Over the years, the role of biochemical, immunological, genetic, and other biological aspects in the pathogenesis of vitiligo has been studied. So far, no convincing model describing the interplay of these contributing factors has been formulated. Based on existing research, we propose that vitiligo has a multi-factorial etiology, characterized by multiple steps, but always involving an increase of external or internal phenol/catechol concentration, serving as a preferred surrogate substrate of tyrosinase, competing with its physiological substrate tyrosine. The conversion of these substrates into reactive quinones is reinforced by a disturbed redox balance (increasing hydrogen peroxide). Such reactive quinones can be covalently bound to the catalytic centre of tyrosinase (haptenation). This could give rise to a new antigen, carried by Langerhans cells to the regional lymph node, stimulating the proliferation of cytotoxic T cells. However, the activation of such cytotoxic cells is only a first step in skin melanocyte killing, which also depends on a shift in the balance between immune defence and tolerance, e.g. resulting from a decrease in properly functioning T-regulatory cells. With this new model, based on a synthesis of several of the existing theories, in mind, the external and internal factors involved in the etiopathogenesis of vitiligo are reviewed, against the background of reported clinical data, experimental studies and existing and potential new therapies. A similar complex mechanism may also lead to some other autoimmune diseases.
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Yoshida Y, Hachiya A, Sriwiriyanont P, Ohuchi A, Kitahara T, Takema Y, Visscher MO, Boissy RE. Functional analysis of keratinocytes in skin color using a human skin substitute model composed of cells derived from different skin pigmentation types. FASEB J 2007; 21:2829-39. [PMID: 17475923 DOI: 10.1096/fj.06-6845com] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Skin color is one of the most distinct features in the human race. To assess the mechanisms of skin color variation, human skin substitutes (HSS) were constructed by grafting mixtures of cultured keratinocytes and melanocytes from a combination of donor skin types, together with light skin derived fibroblasts, into chambers inserted onto the back skin of severe combined immunodeficient (SCID) mice. The resulting complexion coloration of the HSS was relatively darker and lighter when dark and light skin derived keratinocytes, respectively, were combined with melanocytes derived from either light or dark skin. The melanin content in the epidermis and the maturation stage of melanosomes in basal keratinocytes were significantly increased in the HSS composed of dark compared to light skin derived keratinocytes. In addition, the ratio of individual/clustered melanosomes in recipient keratinocytes was increased in the former as opposed to the latter HSS. The genetic expression of endothelin-1, proopiomelanocortin, microphthalmia-associated transcription factor, tyrosinase, GP100, and MART1 were increased in HSS composed of dark vs. light skin derived keratinocytes. These data suggest that our HSS is a promising melanogenic model that demonstrates the role of the keratinocyte in regulating in part both melanogenesis and distribution of transferred melanosomes.
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Affiliation(s)
- Yasuko Yoshida
- Kao Biological Science Laboratories, Haga, Tochigi, Japan
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McNeill MS, Paulsen J, Bonde G, Burnight E, Hsu MY, Cornell RA. Cell death of melanophores in zebrafish trpm7 mutant embryos depends on melanin synthesis. J Invest Dermatol 2007; 127:2020-30. [PMID: 17290233 DOI: 10.1038/sj.jid.5700710] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a broadly expressed, non-selective cation channel. Studies in cultured cells implicate TRPM7 in regulation of cell growth, spreading, and survival. However, zebrafish trpm7 homozygous mutants display death of melanophores and temporary paralysis, but no gross morphological defects during embryonic stages. This phenotype implies that melanophores are unusually sensitive to decreases in Trpm7 levels, a hypothesis we investigate here. We find that pharmacological inhibition of caspases does not rescue melanophore viability in trpm7 mutants, implying that melanophores die by a mechanism other than apoptosis. Consistent with this possibility, ultrastructural analysis of dying melanophores in trpm7 mutants reveals abnormal melanosomes and evidence of a ruptured plasma membrane, indicating that cell death occurs by necrosis. Interestingly, inhibition of melanin synthesis largely prevents melanophore cell death in trpm7 mutants. These results suggest that melanophores require Trpm7 in order to detoxify intermediates of melanin synthesis. We find that unlike TRPM1, TRPM7 is expressed in human melanoma cell lines, indicating that these cells may also be sensitized to reduction of TRPM7 levels.
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Affiliation(s)
- Matthew S McNeill
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA
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Manga P, Sheyn D, Yang F, Sarangarajan R, Boissy RE. A role for tyrosinase-related protein 1 in 4-tert-butylphenol-induced toxicity in melanocytes: Implications for vitiligo. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:1652-62. [PMID: 17071589 PMCID: PMC1780195 DOI: 10.2353/ajpath.2006.050769] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vitiligo presents with depigmented cutaneous lesions following localized melanocyte death. Multiple factors contribute to cell death, including genetically determined susceptibility to trauma, and environmental factors, such as exposure to 4-tert-butylphenol (4-TBP). We demonstrate that 4-TBP induces oxidative stress that is more readily overcome by melanocytes from normally pigmented individuals than from two individuals with vitiligo. The antioxidant catalase selectively and significantly reduced death of melanocytes derived from two individuals with vitiligo, indicating a role for oxidative stress in vitiligo pathogenesis. In normal melanocytes, oxidative stress results in reduced expression of microphthalmia-associated transcription factor (MITF). Melanocyte-stimulating hormone-induced expression of MITF protein caused increased sensitivity to 4-TBP, whereas sensitivity of melanomas correlated with MITF expression. MITF stimulates melanin synthesis by up-regulating expression of melanogenic enzymes such as tyrosinase-related protein-1 (Tyrp1). Although melanin content per se did not affect sensitivity to 4-TBP, expression of Tyrp1 significantly increased sensitivity. Melanocytes and melanomas that express functional Tyrp1 were significantly more sensitive to 4-TBP than Tyrp1-null cells. Thus, normal melanocytes respond to 4-TBP by reducing expression of MITF and Tyrp1. We hypothesize that melanocytes in vitiligo demonstrate reduced ability to withstand oxidative stress due, partly, to a disruption in MITF regulation of Tyrp1.
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Affiliation(s)
- Prashiela Manga
- Department of Dermatology, University of Cincinnati, PO Box 670592, Cincinnati, OH 45267-0592, USA
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Chu CY, Liu YL, Chiu HC, Jee SH. Dopamine-induced apoptosis in human melanocytes involves generation of reactive oxygen species. Br J Dermatol 2006; 154:1071-9. [PMID: 16704636 DOI: 10.1111/j.1365-2133.2006.07293.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Previous studies have shown that significant increases in urinary and plasma levels of several monoamines and their metabolites characterize the onset of vitiligo and its progression. Recently, both epidermal keratinocytes and melanocytes were found to have the capacity for the biosynthesis of several catecholamines and serotonin. Some monoamines and their metabolites can induce apoptosis and cytotoxicity in neural cells. However, no previous report has investigated the potential role of these monoamines in inducing apoptosis or cytotoxicity in melanocytes. OBJECTIVES To study the effects of dopamine (DA), norepinephrine (NE), epinephrine (EP), and serotonin (5-HT) on melanocyte cytotoxicity and apoptosis. METHODS Primary cultures of normal human melanocytes established from the foreskins of normal individuals were treated with different concentrations of DA, NE, EP and 5-HT for 5 and 7 days. Cell viability was measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Melanocyte apoptosis was evaluated by morphological examination and flow cytometric analysis. We also measured the generation of reactive oxygen species (ROS) after DA treatment. RESULTS Among the four monoamines used in this study, only DA had an effect, dose-dependently decreasing the melanocyte viability at concentrations ranging from 0.01 to 100 micromol L(-1) (0.1 and 1 micromol L(-1), P < 0.05; 10 micromol L(-1), P < 0.01). In addition, DA-induced melanocyte apoptosis was evidenced by the increased percentage of sub-G1 cells from 7.71 +/- 0.28% (control) to 12.22 +/- 1.05% (0.1 micromol L(-1) DA) (P < 0.005), and treatment with the antioxidant N-acetylcysteine (NAC) reversed this apoptotic effect. DA treatment led to the generation of ROS, which could be prevented by pretreatment with NAC. CONCLUSIONS DA can induce melanocyte apoptosis, which might be related to the generation of ROS. This novel effect might play an important role in the development or progression of vitiligo, which is currently viewed as a disease process closely related to melanocyte apoptosis.
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Affiliation(s)
- C-Y Chu
- Department of Dermatology, National Taiwan University Hospital and National Taiwan University College of Medicine, 7 Chung-Shan South Road, Taipei 100, Taiwan
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Kroll TM, Bommiasamy H, Boissy RE, Hernandez C, Nickoloff BJ, Mestril R, Le Poole IC. 4-Tertiary butyl phenol exposure sensitizes human melanocytes to dendritic cell-mediated killing: relevance to vitiligo. J Invest Dermatol 2005; 124:798-806. [PMID: 15816839 PMCID: PMC1747533 DOI: 10.1111/j.0022-202x.2005.23653.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The trigger initiating an autoimmune response against melanocytes in vitiligo remains unclear. Patients frequently experience stress to the skin prior to depigmentation. 4-tertiary butyl phenol (4-TBP) was used as a model compound to study the effects of stress on melanocytes. Heat shock protein (HSP)70 generated and secreted in response to 4-TBP was quantified. The protective potential of stress proteins generated following 4-TBP exposure was examined. It was studied whether HSP70 favors dendritic cell (DC) effector functions as well. Melanocytes were more sensitive to 4-TBP than fibroblasts, and HSP70 generated in response to 4-TBP exposure was partially released into the medium by immortalized vitiligo melanocyte cell line PIG3V. Stress protein HSP70 in turn induced membrane tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and activation of DC effector functions towards stressed melanocytes. Melanocytes exposed to 4-TBP demonstrated elevated TRAIL death receptor expression. DC effector functions were partially inhibited by blocking antibodies to TRAIL. TRAIL expression and infiltration by CD11c+ cells was abundant in perilesional vitiligo skin. Stressed melanocytes may mediate DC activation through release of HSP70, and DC effector functions appear to play a previously unappreciated role in progressive vitiligo.
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Affiliation(s)
- Tara M. Kroll
- Department of Pathology/Oncology Institute, Loyola University, Chicago, Illinois, USA
| | - Hemamalini Bommiasamy
- Department of Pathology/Oncology Institute, Loyola University, Chicago, Illinois, USA
| | | | | | - Brian J. Nickoloff
- Department of Pathology/Oncology Institute, Loyola University, Chicago, Illinois, USA
| | - Ruben Mestril
- Department of Physiology/Cardiovascular Institute, Loyola University, Chicago, Illinois, USA
| | - I. Caroline Le Poole
- Department of Pathology/Oncology Institute, Loyola University, Chicago, Illinois, USA
- Address correspondence to: I. Caroline Le Poole, PhD, Cardinal Bernardin Cancer Center, Rm 203, Loyola University Medical Center, 2160 S. 1st Avenue, Maywood, Illinois 60153, USA.
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Abstract
Vitiligo is an acquired depigmentary disorder of the skin that results from the selective destruction of melanocytes, generally during the second decade of life and affecting approximately 1% of the population worldwide. Loss of cutaneous pigment appears to render the skin susceptible to premature aging and cancer. In addition this disease can be socially devastating for afflicted individuals. The etiology of vitiligo is poorly understood. The present dogma suggests that genetic factors render the melanocyte fragile thus predisposing individuals to developing vitiligo. When subjected to instigating factors, these susceptible, fragile melanocytes undergo apoptosis. Autoimmune factors then perpetuate the removal of the melanocyte component from the skin. In the majority of cases the instigating factors are not known (idiopathic vitiligo), however a small sub-set of individuals develop contact/occupational vitiligo following exposure to particular chemicals. Many of these chemicals have been implicated in both contact/occupational vitiligo and chemical leukoderma. Both conditions present with well-defined, depigmented skin lesions that develop following exposure. Only in the case of vitiligo does the depigmentation spread beyond the areas of contact, probably via an immune-mediated mechanism. The largest class of chemicals known to trigger contact/occupational vitiligo is the phenolic/catecholic derivatives. Many have been demonstrated to be preferentially cytotoxic to melanocytes, with high-dose exposure resulting in the initiation of apoptosis. Phenolic/catecholic derivatives are structurally similar to the melanin precursor tyrosine, and therefore tyrosinase was originally implicated as a mediator of cytotoxicity. However, our data suggests that tyrosinase-related protein-1, rather than tyrosinase, facilitates toxicity, possibly by catalytic conversion of the compounds, which results in the generation of radical oxygen species. The ensuing oxidative stress then triggers activation of cellular free radical scavenging pathways to prevent cell death. Genetic inability of melanocytes to tolerate and/or respond to the oxidative stress may underlie the etiology of contact/occupational vitiligo.
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Affiliation(s)
- Raymond E Boissy
- Department of Dermatology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0592, USA.
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Gauthier Y, Cario-Andre M, Lepreux S, Pain C, Taïeb A. Melanocyte detachment after skin friction in non lesional skin of patients with generalized vitiligo. Br J Dermatol 2003; 148:95-101. [PMID: 12534601 DOI: 10.1046/j.1365-2133.2003.05024.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In vitiligo, melanocytes are gradually lost in depigmented macules of the skin. The disappearance of melanocytes has, however, not been clearly observed and consequently the aetiology of the disease (autoimmune, neural, cytotoxic) is still elusive. The starting point of vitiligo macules is frequently determined by local conditions such as wounds and excoriations, but may also follow minor traumas such as pressure or repeated friction. This prominent feature is often neglected. OBJECTIVES To clarify the biological consequences of repeated friction on the attachment and survival of melanocytes in non lesional vitiligo skin. METHODS Light reproducible skin friction was performed for 4 min on the volar forearm of 18 patients with extensive vitiligo and five controls with normal healthy skin. Biopsies from the test area and control skin were taken at 1, 4, 24 and 48 h following friction. Serial sections were examined with standard light microscopy, transmission electron microscopy, histochemistry and immunohistochemistry (dihydroxyphenylalanine, HMB-45, E-cadherin and an early apoptosis marker, M30 cytoDEATH antibody). RESULTS The observation of sections at 1 and 48 h after friction on vitiligo skin and at all time points in controls revealed no changes. In contrast, in vitiligo skin at 4 and 24 h after friction, several melanocytes had undergone detachment and were found in various suprabasal positions, including the stratum spinosum, granular layer, and within and outside the stratum corneum. CONCLUSIONS Detachment and transepidermal elimination of melanocytes following minor mechanical trauma in non lesional vitiligo skin is probably the cause of depigmentation occurring in the isomorphic response (Koebner phenomenon). We propose that transepidermal elimination of melanocytes in vitiligo should be regarded as a possible mechanism of chronic loss of pigment cells, perhaps previously damaged by another process.
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Affiliation(s)
- Y Gauthier
- Department of Dermatology, Centre Hospitalier Universitaire de Bordeaux, Hôpital Saint André, 1 rue Jean Burguet, France.
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Bowen AR, Hanks AN, Allen SM, Alexander A, Diedrich MJ, Grossman D. Apoptosis regulators and responses in human melanocytic and keratinocytic cells. J Invest Dermatol 2003; 120:48-55. [PMID: 12535197 DOI: 10.1046/j.1523-1747.2003.12010.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apoptosis in keratinocytes is required for epidermal turnover, stratum corneum formation, and removal of ultraviolet-damaged premalignant cells. Its role in melanocyte homeostasis and transformation, on the other hand, has not been defined, although apoptosis resistance is a commonly recognized feature of melanoma. We examined the expression of apoptosis regulators in melanocytes, keratinocytes, melanoma, and HaCat cells. Melanocytic cells expressed relatively high levels of Bcl-2, Bcl-X(L), Mcl-1, C-IAP-1, C-IAP-2, XIAP, Livin, and Apaf-1. The only apoptotic regulator that was differentially expressed in melanoma cells and not melanocytes was Survivin, whereas Bax was expressed in melanocytes but not in most melanoma lines. Keratinocytic cells, on the other hand, expressed high levels of FLIP and were relatively deficient in Bcl-2 family proteins. Levels of p53 were highest in HaCat cells and some of the melanoma lines, and barely detectable in melanocytes and keratinocytes. Next, susceptibility of these cells types to apoptosis induced by ultraviolet B, the tyrosine analog 4-tert-butylphenol, and cytotoxic drugs was examined. Melanocytes were relatively resistant to ultraviolet B, whereas keratinocytes were unresponsive to 4-tert-butylphenol. Melanocytes and keratinocytes were generally less susceptible than melanoma lines and HaCat cells to etoposide, cisplatin, and staurosporine. Induction of apoptosis in these cell types was generally associated with decreased levels of Mcl-1, XIAP, and Livin, and increased levels of p53, whereas levels of other apoptotic regulators were unaltered. These results provide insights into the potential roles of apoptosis in the function and transformation of epidermal melanocytes and keratinocytes.
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Affiliation(s)
- Anneli R Bowen
- Department of Dermatology, University of Utah, Salt Lake City, UT 84112, USA
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Abstract
Vitiligo is a common cutaneous disorder that has significant biological and social consequences for those affected. It is characterized by a loss of melanocytes from the epidermis, which results in the absence of melanin, i.e. depigmentation. There are numerous hypotheses about the etiology of vitiligo, but no data to definitively prove one theory over another. It is likely that there are numerous causes for the loss of these melanocytes. One way to approach the identification of the etiology is to determine the mechanism by which the melanocytes are destroyed. The two known mechanisms for the destruction of cells are necrosis and apoptosis. One purpose of this paper is to review the extant data that might suggest which of the two mechanisms is operative against melanocytes in patients with vitiligo. The histological data, and some laboratory data, support apoptosis, rather than necrosis, as the mechanism for removal of melanocytes. Apoptosis can be induced by a variety of factors, including immune cytokines, some environmental chemicals (for example substituted hydroquinones such as monobenzone) or other molecular mechanisms. Current therapies, such as corticosteroids and ultraviolet light, do affect apoptosis in a variety of ways. Confirmation of apoptosis as a mechanism, and identification of how apoptosis is initiated to produce vitiligo, can serve as a basis for devising medications that might stop the progression of the disorder. The problem of vitiligo would be essentially solved if there was a medication that is well tolerated in children, adults and pregnant women, and that would halt the progression of the depigmentation. The study of apoptosis, mechanisms of its induction, and the ways to block apoptosis, is one possible way to find both the causes of depigmentation and medications to prevent its progression.
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Affiliation(s)
- Carol L Huang
- Department of Dermatology, University of Cincinnati, Pavilion A, Ohio 45267-0523, USA
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