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Insulin-like growth factor-I rescue of primary keratinocytes from pre- and post-ultraviolet B radiation effects. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 209:111951. [DOI: 10.1016/j.jphotobiol.2020.111951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 01/13/2023]
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2
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Andrade MJ, Van Lonkhuyzen DR, Upton Z, Satyamoorthy K. Unravelling the insulin-like growth factor I-mediated photoprotection of the skin. Cytokine Growth Factor Rev 2019; 52:45-55. [PMID: 31767341 DOI: 10.1016/j.cytogfr.2019.11.004] [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: 10/17/2019] [Revised: 11/12/2019] [Accepted: 11/14/2019] [Indexed: 10/25/2022]
Abstract
Chronic exposure of human skin to solar ultraviolet radiation (UVR) induces a range of biological reactions which may directly or indirectly lead to the development of skin cancer. In order to overcome these damaging effects of UVR and to reduce photodamage, the skin's endogenous defence system functions in concert with the various exogenous photoprotectors. Growth factors, particularly insulin-like growth factor-I (IGF-I), produced within the body as a result of cellular interaction in response to UVR demonstrates photoprotective properties in human skin. This review summarises the impact of UVR-induced photolesions on human skin, discusses various endogenous as well as exogenous approaches of photoprotection described to date and explains how IGF-I mediates UVR photoprotective responses at the cellular and mitochondrial level. Further, we describe the current interventions using growth factors and propose how the knowledge of the IGF-I photoprotection signalling cascades may direct the development of improved UVR protection and remedial strategies.
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Affiliation(s)
- Melisa J Andrade
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India; Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Derek R Van Lonkhuyzen
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Zee Upton
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; Institute of Medical Biology, A⁎STAR, Singapore
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India.
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Zehlila A, Schaumann A, Mlouka AB, Bourguiba I, Hardouin J, Masmoudi O, Cosette P, Amri M, Jouenne T. Glioprotective effect of Ulva rigida extract against UVB cellular damages. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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Wu Q, Wu S. The role of lipid raft translocation of prohibitin in regulation of Akt and Raf-protected apoptosis of HaCaT cells upon ultraviolet B irradiation. Mol Carcinog 2017; 56:1789-1797. [PMID: 28218425 DOI: 10.1002/mc.22636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/31/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022]
Abstract
Prohibitin (PHB) plays a role in regulation of ultraviolet B light (UVB)-induced apoptosis of human keratinocytes, HaCaT cells. The regulatory function of PHB appears to be associated with its lipid raft translocation. However, the detailed mechanism for PHB-mediated apoptosis of these keratinocytes upon UVB irradiation is not clear. In this report, we determined the role of lipid raft translocation of PHB in regulation of UVB-induced apoptosis. Our data show that upon UVB irradiation PHB is translocated from the non-raft membrane to the lipid rafts, which is correlated with a release of both Akt and Raf from membrane. Overexpression of Akt and/or Raf impedes UVB-induced lipid raft translocation of PHB. Immunoprecipitation analysis indicates that UVB alters the interactions among PHB, Akt, and Raf. Reduced expression of PHB leads to a decreased phosphorylation of Akt and ERK, as well as a decreased activity of Akt, and increased apoptosis of the cells upon UVB irradiation. These results suggest that PHB regulates UVB-induced apoptosis of keratinocytes via a mechanism that involves detachment from Akt and Raf on the plasma membrane, and sequential lipid raft translocation.
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Affiliation(s)
- Qiong Wu
- Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio
| | - Shiyong Wu
- Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, Ohio
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5
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Dong TK, Ona K, Scandurra AE, Demetriou SK, Oh DH. Deficient Nucleotide Excision Repair in Squamous Cell Carcinoma Cells. Photochem Photobiol 2016; 92:760-6. [PMID: 27499003 DOI: 10.1111/php.12625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/10/2016] [Indexed: 11/30/2022]
Abstract
Squamous cell carcinomas (SCCs) are associated with ultraviolet radiation and multiple genetic changes, but the mechanisms leading to genetic instability are unclear. SCC cell lines were compared to normal keratinocytes for sensitivity to ultraviolet radiation, DNA repair kinetics and DNA repair protein expression. Relative to normal keratinocytes, four SCC cell lines were all variably sensitive to ultraviolet radiation and, except for the SCC25 cell line, were deficient in global repair of cyclobutane pyrimidine dimers, although not 6-4 photoproducts. Impaired DNA repair of cyclobutane pyrimidine dimers was associated with reduced mRNA expression from XPC but not DDB2 genes which each encode key DNA damage recognition proteins. However, levels of XPC or DDB2 proteins or both were variably reduced in repair-deficient SCC cell lines. p53 levels did not correlate with DNA repair activity or with XPC and DDB2 levels, but p63 levels were deficient in cell lines with reduced global repair. Repair-proficient SCC25 cells depleted of p63 lost XPC expression, early global DNA repair activity and UV resistance. These results demonstrate that some SCC cell lines are deficient in global nucleotide excision repair and support a role for p63 as a regulator of nucleotide excision repair in SCCs.
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Affiliation(s)
- Tiffany K Dong
- Dermatology Research Unit, San Francisco VA Medical Center, San Francisco, CA.,Department of Dermatology, University of California at San Francisco, San Francisco, CA
| | - Katherine Ona
- Dermatology Research Unit, San Francisco VA Medical Center, San Francisco, CA
| | - Amy E Scandurra
- Dermatology Research Unit, San Francisco VA Medical Center, San Francisco, CA
| | - Stephanie K Demetriou
- Dermatology Research Unit, San Francisco VA Medical Center, San Francisco, CA.,Department of Dermatology, University of California at San Francisco, San Francisco, CA
| | - Dennis H Oh
- Dermatology Research Unit, San Francisco VA Medical Center, San Francisco, CA. .,Department of Dermatology, University of California at San Francisco, San Francisco, CA.
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Belleudi F, Purpura V, Caputo S, Torrisi MR. FGF7/KGF regulates autophagy in keratinocytes: A novel dual role in the induction of both assembly and turnover of autophagosomes. Autophagy 2014; 10:803-21. [PMID: 24577098 PMCID: PMC5119059 DOI: 10.4161/auto.28145] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy is a degradative pathway through which cells overcome stressful conditions and rapidly change their phenotype during differentiation. Despite its protective role, when exacerbated, autophagy may lead to cell death. Several growth factors involved in cell survival and in preventing differentiation are able to inhibit autophagy. Here we investigated the autophagic role of FGF7/KGF, an important player in epithelial cell protection and differentiation. Biochemical and quantitative fluorescence approaches showed that FGF7 and its signaling induce autophagy in human keratinocytes and the use of specific inhibitors indicated that this effect is independent of the PI3K-AKT-MTOR pathway. The selective block of autophagosome-to-lysosome fusion clarified that FGF7 induces autophagy stimulating autophagosome formation. However, quantitative fluorescence approaches also indicated that, upon a prolonged autophagic stimulus, FGF7 is able to accelerate autophagosome turnover. Moreover, in differentiating keratinocytes, the use of the autophagic inhibitor 3-MA as well as the depletion of BECN1 and ATG5, 2 essential regulators of the process, counteracted the FGF7-induced increase of the differentiation marker KRT1/K1, suggesting that autophagy is required for the FGF7-mediated early differentiation. These results provide the first evidence of a role of FGF7 in the regulation of sequential steps of the autophagic process and strengthen the hypothesis of a direct interplay between autophagy and differentiation. On the other hand, the ability of FGF7 to accelerate autophagosome turnover, preventing their dangerous accumulation, is consistent with the well-established protective role played by the growth factor in epithelial cells.
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Affiliation(s)
- Francesca Belleudi
- Istituto Pasteur-Fondazione Cenci Bolognetti; Dipartimento di Medicina Clinica e Molecolare; Sapienza Università di Roma; Rome, Italy
| | - Valeria Purpura
- Istituto Pasteur-Fondazione Cenci Bolognetti; Dipartimento di Medicina Clinica e Molecolare; Sapienza Università di Roma; Rome, Italy
| | - Silvia Caputo
- Istituto Pasteur-Fondazione Cenci Bolognetti; Dipartimento di Medicina Clinica e Molecolare; Sapienza Università di Roma; Rome, Italy
| | - Maria Rosaria Torrisi
- Istituto Pasteur-Fondazione Cenci Bolognetti; Dipartimento di Medicina Clinica e Molecolare; Sapienza Università di Roma; Rome, Italy; Azienda Ospedaliera S. Andrea; Rome, Italy
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Yelskaya Z, Carrillo V, Dubisz E, Gulzar H, Morgan D, Mahajan SS. Synergistic inhibition of survival, proliferation, and migration of U87 cells with a combination of LY341495 and Iressa. PLoS One 2013; 8:e64588. [PMID: 23724064 PMCID: PMC3664620 DOI: 10.1371/journal.pone.0064588] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 04/16/2013] [Indexed: 11/18/2022] Open
Abstract
Glioblastomas exploit various molecular pathways to promote glutamate- dependent growth by activating the AMPA (2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propanoic acid) receptor, the group II metabotropic glutamate receptor, mGluR, and the epidermal growth factor receptor, EGFR. We hypothesized that targeting more than one of these pathways would be more effective in inhibiting glutamate-dependent growth. Using a model of U87 cell line, we show that blocking glutamate release by Riluzole inhibits cell proliferation. Glutamate-dependent growth is effectively inhibited by a combination of Iressa, an inhibitor of EGFR activation and LY341495, a group II mGluR inhibitor. Treatment of U87 cells with a combination of Iressa and LY341495 inhibits proliferation as indicated by Ki-67 staining, induces apoptosis and inhibits migration of U87 cells more effectively than the treatment by Iressa or LY341495 alone. These results demonstrate that a combinatorial therapy with Iressa and LY341495 is more effective due to synergistic effects of these drugs in inhibiting the growth of glioblastoma.
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Affiliation(s)
- Zarina Yelskaya
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Vangie Carrillo
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Ewa Dubisz
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Hira Gulzar
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Devon Morgan
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
| | - Shahana S. Mahajan
- Department of Health Sciences, Hunter College, City University of New York, New York, New York, United States of America
- * E-mail:
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Chen CF, Chu CY, Chen TH, Lee SJ, Shen CN, Hsiao CD. Establishment of a transgenic zebrafish line for superficial skin ablation and functional validation of apoptosis modulators in vivo. PLoS One 2011; 6:e20654. [PMID: 21655190 PMCID: PMC3105106 DOI: 10.1371/journal.pone.0020654] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 05/09/2011] [Indexed: 01/31/2023] Open
Abstract
Background Zebrafish skin is composed of enveloping and basal layers which form a first-line defense system against pathogens. Zebrafish epidermis contains ionocytes and mucous cells that aid secretion of acid/ions or mucous through skin. Previous studies demonstrated that fish skin is extremely sensitive to external stimuli. However, little is known about the molecular mechanisms that modulate skin cell apoptosis in zebrafish. Methodology/Principal Findings This study aimed to create a platform to conduct conditional skin ablation and determine if it is possible to attenuate apoptotic stimuli by overexpressing potential apoptosis modulating genes in the skin of live animals. A transgenic zebrafish line of Tg(krt4:NTR-hKikGR)cy17 (killer line), which can conditionally trigger apoptosis in superficial skin cells, was first established. When the killer line was incubated with the prodrug metrodinazole, the superficial skin displayed extensive apoptosis as judged by detection of massive TUNEL- and active caspase 3-positive signals. Great reductions in NTR-hKikGR+ fluorescent signals accompanied epidermal cell apoptosis. This indicated that NTR-hKikGR+ signal fluorescence can be utilized to evaluate apoptotic events in vivo. After removal of metrodinazole, the skin integrity progressively recovered and NTR-hKikGR+ fluorescent signals gradually restored. In contrast, either crossing the killer line with testing lines or transiently injecting the killer line with testing vectors that expressed human constitutive active Akt1, mouse constitutive active Stat3, or HPV16 E6 element displayed apoptosis-resistant phenotypes to cytotoxic metrodinazole as judged by the loss of reduction in NTR-hKikGR+ fluorescent signaling. Conclusion/Significance The killer/testing line binary system established in the current study demonstrates a nitroreductase/metrodinazole system that can be utilized to conditionally perform skin ablation in a real-time manner, and provides a valuable tool to visualize and quantify the anti-apoptotic potential of interesting target genes in vivo. The current work identifies a potential use for transgenic zebrafish as a high-throughput platform to validate potential apoptosis modulators in vivo.
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Affiliation(s)
- Chi-Fang Chen
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
| | - Che-Yu Chu
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
| | - Te-Hao Chen
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan
| | - Shyh-Jye Lee
- Institute of Zoology, National Taiwan University, Taipei, Taiwan
| | - Chia-Ning Shen
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
- Genome Research Center, Academia Sinica, NanKang, Taipei, Taiwan
- * E-mail: (C-NS); (C-DH)
| | - Chung-Der Hsiao
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taiwan
- Center for Nanotechnology, Chung Yuan Christian University, Chung-Li, Taiwan
- * E-mail: (C-NS); (C-DH)
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Papadakis ES, Cichoń MA, Vyas JJ, Patel N, Ghali L, Cerio R, Storey A, O'Toole EA. Axl promotes cutaneous squamous cell carcinoma survival through negative regulation of pro-apoptotic Bcl-2 family members. J Invest Dermatol 2011; 131:509-17. [PMID: 21068757 DOI: 10.1038/jid.2010.326] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Expression of Axl, a receptor tyrosine kinase, is increased in cutaneous squamous cell carcinoma (SCC). Examination of a series of cutaneous SCC tumors revealed positive phospho-Akt (P-Akt) staining accompanied by weak TUNEL staining in Axl-positive tumors, suggesting an anti-apoptotic role for Axl in SCC survival. The role of Axl in UV-induced apoptosis was investigated in a cutaneous SCC cell line using retroviral short hairpin RNA sequences enabling stable Axl knock-down. We show that, although Axl knock-down has no effect on cell proliferation, it sensitizes cells to UV-induced apoptosis through increased activation of the pro-apoptotic protein Bad, a change in the conformation of Bax and Bak, release of cytochrome c into the cytosol, and activation of caspases. These events are accompanied by faster Akt dephosphorylation in UV-treated Axl knock-down cells and correlate with the degree of Axl knock-down. Treatment with the pan-caspase inhibitor zVAD-fmk partially rescued cells from UV-induced apoptosis but did not affect Bid cleavage or cytochrome c release, suggesting that cells die via the mitochondrial-mediated pathway. Thus, Axl confers resistance of SCC cells to apoptosis and displays potential as a target for therapeutic intervention in cutaneous SCC.
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Affiliation(s)
- Emmanouil S Papadakis
- Centre for Cutaneous Research, Blizard Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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10
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Lei X, Liu B, Han W, Ming M, He YY. UVB-Induced p21 degradation promotes apoptosis of human keratinocytes. Photochem Photobiol Sci 2010; 9:1640-8. [PMID: 20931139 DOI: 10.1039/c0pp00244e] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Skin cancer is the most common cancer in the United States. Ultraviolet B (UVB) radiation in sunlight is the major environmental factor causing skin cancer. p21, a p53-inducible protein, plays an important role in cell cycle, DNA repair, and apoptosis. Here we have investigated the effect of UVB radiation on p21 and its molecular mechanisms and function in human HaCaT keratinocytes, which we used as a premalignant cellular model because normal skin harbors numerous clones of p53-mutated keratinocytes. We found that in human HaCaT keratinocytes UVB induces rapid p21 down-regulation via a proteasomal degradation mechanism. In p53-defective HaCaT cells, the p21 protein levels remain decreased at a later time post-UVB, but in normal human and mouse epidermal keratinocytes with wild-type p53 the p21 levels are initially reduced but later increase post-UVB. These findings indicate that loss of p53 function leads to sustained p21 down-regulation in response to UVB damage. Degradation of p21 following UVB radiation does not require ATR, ATM, or both, because either the ATR/ATM inhibitor caffeine or siRNA knockdown of ATR, ATM, or both failed to reverse p21 degradation. However, inhibiting MDM2 or GSK3β partially reduced UVB-induced p21 degradation, while inhibiting both enzymes completely prevented it. Restoring the p21 protein levels in UVB-irradiated keratinocytes reduced apoptosis. Although at the molecular level increasing p21 expression has no effect on the protein levels of the Bcl-2 family members, it enhances the activation of AKT, a critical survival pathway to protect cells from apoptosis. Our results suggest a distinct mechanism of p21 degradation in keratinocytes by UVB, and this p21 degradation may significantly enhance UVB-induced apoptosis of premalignant keratinocytes with a p53 defect to eliminate damaged cells and therefore prevent skin cancer development.
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Affiliation(s)
- Xia Lei
- Section of Dermatology, Department of Medicine, University of Chicago, Chicago, IL, USA
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Zutterman N, Maes H, Claerhout S, Agostinis P, Garmyn M. Deregulation of cell-death pathways as the cornerstone of skin diseases. Clin Exp Dermatol 2009; 35:569-75. [PMID: 19874372 DOI: 10.1111/j.1365-2230.2009.03614.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Deregulation of cell-death pathways plays a key role in the pathogenesis of various skin diseases. The different types of cell death are mainly defined by morphological criteria, and include apoptosis, autophagic cell death, and necrosis. The process of apoptosis is well characterized at the molecular level and involves the activation of two main pathways, the intrinsic and extrinsic pathways, converging into the execution of apoptosis by intracellular cysteine proteases, called caspases. The relevance and implication of these apoptotic pathways in the pathophysiology of skin diseases, such as toxic epidermal necrolysis, graft-versus-host disease and skin cancer, has been extensively studied. The role of autophagic cell death in progression of skin tumours and response to cytotoxic drugs is only beginning to be elucidated.
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Affiliation(s)
- N Zutterman
- Laboratory of Dermatology, Catholic University of Leuven, Herestraat 49, Bus 724, B-3000 Leuven, Belgium
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12
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Ibuki Y, Akaike M, Toyooka T, Goto R. Akt1-mediated intracellular oxidation after UVB irradiation suppresses apoptotic cell death induced by cell detachment and serum starvation. Photochem Photobiol 2008; 84:154-61. [PMID: 18173715 DOI: 10.1111/j.1751-1097.2007.00214.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apoptosis is an important cell death system that deletes damaged and mutated cells to prevent cancer. We have previously reported that a certain dose of UVB irradiation inhibited the apoptosis induced by serum starvation and cell detachment, leading to cell transformation. This antiapoptotic effect was partially inhibited by phosphatidylinositol 3-kinase (PI3-kinase) inhibitors. UVB irradiation is known to cause the phosphorylation of Akt via the activation of PI3-kinase; however, the Akt isoform-specific relationship has not yet been clarified. Notably, the role in antiapoptotic effect of UVB has yet to be elucidated. In this study, the role of Akt1 in the UVB-induced inhibition of apoptosis was examined by Akt1 knockdown using small interfering RNA (siRNA). NIH3T3 cells showed typical apoptotic cell death by serum starvation and cell detachment, which was significantly inhibited by UVB irradiation. Akt1 knockdown decreased the antiapoptotic effect of UVB. Hydrogen peroxide-induced suppression of cell death was also decreased in Akt1 knockdown cells. An antioxidant, N-acetylcysteine, inhibited the antiapoptotic effect by UVB irradiation, whereas no inhibition was observed in Akt1 knockdown cells. Furthermore, UVB-induced intracellular peroxidation was not observed in the knockdown cells, indicating that Akt1 played an important role in mediating the intracellular redox status. Treatment with insulin had a similar antiapoptotic effect as UVB irradiation involving intracellular peroxidation, which was also attenuated in Akt1 knockdown cells. These findings suggest that appropriate intracellular oxidation after UVB irradiation prevented apoptosis, a process which might be partially regulated by the production of reactive oxygen species mediated by Akt1.
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Affiliation(s)
- Yuko Ibuki
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka-shi, Japan.
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Lotti LV, Rotolo S, Francescangeli F, Frati L, Torrisi MR, Marchese C. AKT and MAPK signaling in KGF-treated and UVB-exposed human epidermal cells. J Cell Physiol 2007; 212:633-42. [PMID: 17458890 DOI: 10.1002/jcp.21056] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Regulation of proliferation and differentiation in keratinocyte is a complex and dynamic process that involves activation of multiple signaling pathways triggered by different growth factors. Keratinocyte growth factor (KGF) is not only a potent mitogen, but differently from other growth factors, is a potent inducer of differentiation. The MAP kinase and AKT pathways are involved in proliferation and differentiation of many cell types including keratinocytes. We investigated here the role of KGF in modulating AKT and MAPK activity during differentiation of human keratinocytes. Our results show that the mechanisms of action of KGF are dose-dependent and that a sustained activation of the MAPK signaling cascade causes a negative regulation of AKT. We also demostrated increasing expression of KGFR substrates, such as PAK4 during keratinocyte differentiation parallel to the receptor upregulation.
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Affiliation(s)
- Lavinia Vittoria Lotti
- Department of Experimental Medicine, University Sapienza, Viale Regina Elena, Rome, Italy
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14
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Claerhout S, Decraene D, Van Laethem A, Van Kelst S, Agostinis P, Garmyn M. AKT Delays the Early-Activated Apoptotic Pathway in UVB-Irradiated Keratinocytes Via BAD Translocation. J Invest Dermatol 2007; 127:429-38. [PMID: 16932738 DOI: 10.1038/sj.jid.5700533] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Upon irradiation with a high dose of UVB, keratinocytes undergo apoptosis as a protective mechanism. In previous work, we demonstrated the existence of an early-activated UVB-induced apoptotic pathway in growth factor-depleted human keratinocytes, which can be substantially delayed by the exclusive supplementation of IGF-1. We now show that in human keratinocytes, IGF-1 inhibits the onset of UVB-triggered apoptosis through a transcriptional independent, AKT-mediated mechanism, involving BAD serine 136 phosphorylation. Our results show that the early UVB-induced apoptosis in growth factor-depleted human keratinocytes is exclusively triggered through the mitochondrial pathway. It is accompanied by BAX translocation, cytochrome c release, and procaspase-9 cleavage, but not by procaspase-8 or BID cleavage. In human keratinocytes, IGF-1 supplementation inhibits these events in a transcription-independent manner. Both IGF-1 supplementation and the transduction of a membrane-targeted form of AKT result in a shift of the BH3-only protein BAD from the mitochondria to the cytoplasm, paralleled by an increase of AKT-specific Ser136 phospho-BAD bound to 14-3-3zeta protein. These data indicate that AKT-induced BAD phosphorylation and its subsequent cytoplasmic sequestration by 14-3-3zeta is a major mechanism responsible for the postponement of UVB-induced apoptosis in human keratinocytes.
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Affiliation(s)
- Sofie Claerhout
- Laboratory of Dermatology, University of Leuven, Leuven, Belgium
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15
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Simbulan-Rosenthal CM, Daher A, Trabosh V, Chen WC, Gerstel D, Soeda E, Rosenthal DS. Id3 induces a caspase-3- and -9-dependent apoptosis and mediates UVB sensitization of HPV16 E6/7 immortalized human keratinocytes. Oncogene 2006; 25:3649-60. [PMID: 16449966 DOI: 10.1038/sj.onc.1209407] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Inhibitor of differentiation/DNA binding (Id) proteins comprise a class of helix-loop-helix transcription factors involved in proliferation, differentiation, apoptosis, and carcinogenesis. We have shown that while Id2 is induced by UVB in primary keratinocytes, Id3 is upregulated only in immortalized cells. We have now determined that the consequences of ectopic expression of Id3 protein are strikingly different between immortalized and primary keratinocytes. Overexpression of Id3 induces a significant increase in apoptotic cells as revealed by Annexin V positivity as well as proteolytic processing of caspase-3 in immortalized, but not in primary keratinocytes. Id3-green fluorescent protein (GFP)-positive cells exhibited a fivefold increase in apoptotic nuclear fragmentation compared to Id3-GFP-negative cells. These apoptotic responses were accompanied by activation of caspase-3, as shown by immunocytochemical staining with antibodies to active caspase-3. Immunostaining with antibodies to the active form of caspase-9 as well as to the active form of Bax further revealed that induction of apoptosis in Id3-overexpressing keratinocytes occurred via a mitochondrial-caspase-9-mediated pathway. Coexpression of dominant-negative caspase-9 with Id3 significantly suppressed apoptotic nuclear fragmentation, indicating that caspase-9 activation is essential for Id3-induced cell death. This response was also markedly attenuated by coexpression with the Bax antagonist antiapoptotic protein Bcl2, confirming a role for Bax activation in this apoptotic response. Id3-induced Bax activation may result from increased expression of Bax protein. Furthermore, reduction of Id3 expression by small interfering RNAs abrogated the UVB-induced proteolytic activation of caspase-3 in these cells. These data together suggest that UVB-induced apoptosis of immortalized keratinocytes is at least in part due to Id3 upregulation in these cells.
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Affiliation(s)
- C M Simbulan-Rosenthal
- Department of Biochemistry and Molecular Biology, Georgetown University School of Medicine, Washington, DC 20007, USA
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16
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Daher A, Simbulan-Rosenthal CM, Rosenthal DS. Apoptosis induced by ultraviolet B in HPV-immortalized human keratinocytes requires caspase-9 and is death receptor independent. Exp Dermatol 2006; 15:23-34. [PMID: 16364028 DOI: 10.1111/j.0906-6705.2005.00384.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ultraviolet B (UVB) induces both apoptosis and skin cancer. We found that human keratinocytes (KC) immortalized by Human Papillomavirus (HPV)16 E6/E7 were sensitized to UVB-induced apoptosis, possibly representing a transient regression-prone precancerous stage equivalent to actinic keratosis. To further examine which caspases are apical and essential, we utilized retroviral constructs expressing dominant-negative caspase-9 (caspase-9-DN) or Fas-associated protein with death domain (FADD)-DN as well as caspase inhibitor peptides. Caspase-9-DN and zLEHD-fmk both suppressed caspase-9, -3, and -8 activity after UVB exposure, as well as proteolytic processing of procaspase-3 into its active form, DNA fragmentation factor 45 cleavage, and internucleosomal DNA fragmentation. By contrast, stable expression of FADD-DN in HPV-immortalized KC did not inhibit UVB-induced activation of caspases-9, -3, and -8 nor downstream apoptotic events, although inhibition of caspase-8 with zIETD-fmk attenuated apoptosis. This study indicates that caspase-9 activation is upstream of caspases-3 and -8 and that UVB-induced apoptosis in HPV-immortalized human KC is death receptor (DR) independent and requires both caspase-9 upstream and caspase-8 downstream for maximal apoptosis. These studies further indicate that cell type as well as transformation state determine the sensitivity and mode of cell death (DR vs. mitochondrial apoptotic pathways) in response to UVB and explain the high regression rates of premalignant lesions.
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Affiliation(s)
- Ahmad Daher
- Department of Biochemistry and Molecular Biology, Georgetown University School of Medicine, Washington, DC 20007, USA
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Claerhout S, Van Laethem A, Agostinis P, Garmyn M. Pathways involved in sunburn cell formation: deregulation in skin cancer. Photochem Photobiol Sci 2006; 5:199-207. [PMID: 16465306 DOI: 10.1039/b504970a] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The incidence of squamous cell carcinoma of the skin is rising worldwide for decades. Chronic exposure to sunlight is the most important environmental risk factor for this type of skin cancer. This is predominantly due to the DNA damaging effect of ultraviolet-B (UVB) in sunlight. UVB induces also sunburn cells, i.e. apoptotic keratinocytes, which is a crucial protective mechanism against the carcinogenic effects of UVB irradiation. This process is regulated by a wide range of molecular determinants involved in the balance between pro- and anti-apoptotic pathways. Growing evidence suggests that the deregulation of this balance by chronic UVB irradiation, contributes to the development of skin cancer. This review gives a brief summary of major known pathways involved in the regulation of keratinocyte survival and cell death upon UVB damage and discusses the contribution of the deregulation of these cascades to photocarcinogenesis.
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Affiliation(s)
- Sofie Claerhout
- Laboratory of Dermatology, Faculty of Medicine, Catholic University of Leuven, Herestraat 49, bus 818, B-3000 Leuven, Belgium
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Van Laethem A, Claerhout S, Garmyn M, Agostinis P. The sunburn cell: Regulation of death and survival of the keratinocyte. Int J Biochem Cell Biol 2005; 37:1547-53. [PMID: 15896663 DOI: 10.1016/j.biocel.2005.02.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 01/24/2005] [Accepted: 02/13/2005] [Indexed: 11/17/2022]
Abstract
Sunburn cells are keratinocytes undergoing apoptosis after they have received a physiological UVB dose that irreversibly and severely damaged their DNA or other chromophores. If these cells would escape programmed cell death, a cancer prone phenotype could arise. On the other hand, if the decision to die is made too prematurely, the proliferative compartment of basal keratinocytes would be inevitably lost, thereby hampering normal skin homeostasis. Pro- and anti-apoptotic mediators carefully control crucial points of the cell death program by regulating complex signalling cascades originating at the cell membrane, the nucleus and the cytoplasm. The balance between survival and apoptogenic factors determines the final cell fate, and growing evidence suggests that the deregulation of this balance by chronic UVB stress, results in the development of skin malignancy. The present paper reviews recent data on the major pathways regulating UVB-induced sunburn cell formation and implicates the deregulation of these pathways in the development of skin cancer.
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Affiliation(s)
- An Van Laethem
- Division of Biochemistry, Catholic University of Leuven, Herestraat 49, B-3000, Belgium
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Thumiger SP, Adams TE, Werther GA, Wraight CJ, Edmondson SR. UV induced responses of the human epidermal IGF system: impaired anti-apoptotic effects of IGF-I in HaCaT keratinocytes. Growth Factors 2005; 23:151-9. [PMID: 16019437 DOI: 10.1080/08977190500153680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The insulin-like growth factor receptor (IGF-IR) is critical in epidermal development and IGF binding protein-3 (IGFBP-3), a modulator of cellular activity with or without IGF-dependence, co-localises with epidermal IGF-IRs. We have investigated whether the greater UV susceptibility of a human keratinocyte cell line (HaCaT) in comparison to normal human keratinocytes (NHKs) may involve differences in the IGF system. At 24 h after UV (960 mJ/cm(2) UVB), in comparison to NHKs, HaCaT keratinocytes exhibited significantly higher levels of apoptosis, refractoriness to IGF-I treatment and reduced IGF-IR phosphorylation. Secreted, intact IGFBP-3 (38-42 kDa) and IGFBP-3 mRNA abundance were reduced in HaCaT keratinocytes, but not consistently altered in NHKs. Immunoreactive IGFBP-3 fragments (16-11 kDa) were detected in both UV-exposed cultures. These data suggest that an altered IGF system contributes to HaCaT keratinocyte UV susceptibility and that following UV insult the IGF system may enhance keratinocyte viability and contribute to a return to epidermal homeostasis.
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Affiliation(s)
- Susan P Thumiger
- Centre for Hormone Research, Murdoch Childrens Research Institute, Royal Children's Hospital, University of Melbourne, Flemington Road, Parkville, Victoria, Australia
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