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Loftus SN, Gharaee-Kermani M, Xu B, Moore TM, Hannoudi A, Mallbris MJ, Klein B, Gudjonsson JE, Kahlenberg JM. Interferon alpha promotes caspase-8 dependent ultraviolet light-mediated keratinocyte apoptosis via interferon regulatory factor 1. Front Immunol 2024; 15:1384606. [PMID: 38660315 PMCID: PMC11039837 DOI: 10.3389/fimmu.2024.1384606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 03/27/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction Ultraviolet (UV) light is a known trigger of both cutaneous and systemic disease manifestations in lupus patients. Lupus skin has elevated expression of type I interferons (IFNs) that promote increased keratinocyte (KC) death after UV exposure. The mechanisms by which KC cell death is increased by type I IFNs are unknown. Methods Here, we examine the specific cell death pathways that are activated in KCs by type I IFN priming and UVB exposure using a variety of pharmacological and genetic approaches. Mice that overexpress Ifnk in the epidermis were exposed to UVB light and cell death was measured. RNA-sequencing from IFN-treated KCs was analyzed to identify candidate genes for further analysis that could drive enhanced cell death responses after UVB exposure. Results We identify enhanced activation of caspase-8 dependent apoptosis, but not other cell death pathways, in type I IFN and UVB-exposed KCs. In vivo, overexpression of epidermal Ifnk resulted in increased apoptosis in murine skin after UVB treatment. This increase in KC apoptosis was not dependent on known death ligands but rather dependent on type I IFN-upregulation of interferon regulatory factor 1 (IRF1). Discussion These data suggest that enhanced sensitivity to UV light exhibited by lupus patients results from type I IFN priming of KCs that drives IRF1 expression resulting in caspase-8 activation and increased apoptosis after minimal exposures to UVB.
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Affiliation(s)
- Shannon N. Loftus
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, United States
| | - Mehrnaz Gharaee-Kermani
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
| | - Bin Xu
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Tyson M. Moore
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Andrew Hannoudi
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Mischa J. Mallbris
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Benjamin Klein
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | | | - J. Michelle Kahlenberg
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
- Department of Dermatology, University of Michigan, Ann Arbor, MI, United States
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2
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Cloete I, Smith VM, Jackson RA, Pepper A, Pepper C, Vogler M, Dyer MJS, Mitchell S. Computational modeling of DLBCL predicts response to BH3-mimetics. NPJ Syst Biol Appl 2023; 9:23. [PMID: 37280330 PMCID: PMC10244332 DOI: 10.1038/s41540-023-00286-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023] Open
Abstract
In healthy cells, pro- and anti-apoptotic BCL2 family and BH3-only proteins are expressed in a delicate equilibrium. In contrast, this homeostasis is frequently perturbed in cancer cells due to the overexpression of anti-apoptotic BCL2 family proteins. Variability in the expression and sequestration of these proteins in Diffuse Large B cell Lymphoma (DLBCL) likely contributes to variability in response to BH3-mimetics. Successful deployment of BH3-mimetics in DLBCL requires reliable predictions of which lymphoma cells will respond. Here we show that a computational systems biology approach enables accurate prediction of the sensitivity of DLBCL cells to BH3-mimetics. We found that fractional killing of DLBCL, can be explained by cell-to-cell variability in the molecular abundances of signaling proteins. Importantly, by combining protein interaction data with a knowledge of genetic lesions in DLBCL cells, our in silico models accurately predict in vitro response to BH3-mimetics. Furthermore, through virtual DLBCL cells we predict synergistic combinations of BH3-mimetics, which we then experimentally validated. These results show that computational systems biology models of apoptotic signaling, when constrained by experimental data, can facilitate the rational assignment of efficacious targeted inhibitors in B cell malignancies, paving the way for development of more personalized approaches to treatment.
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Affiliation(s)
- Ielyaas Cloete
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK
| | - Victoria M Smith
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
- The Ernest and Helen Scott Haematological Research Institute, Leicester Cancer Research center, University of Leicester, Leicester, UK
| | - Ross A Jackson
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
- The Ernest and Helen Scott Haematological Research Institute, Leicester Cancer Research center, University of Leicester, Leicester, UK
| | - Andrea Pepper
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK
| | - Chris Pepper
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK
| | - Meike Vogler
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany
| | - Martin J S Dyer
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
- The Ernest and Helen Scott Haematological Research Institute, Leicester Cancer Research center, University of Leicester, Leicester, UK
| | - Simon Mitchell
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK.
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Brash DE. Rethinking Causation for Data-intensive Biology: Constraints, Cancellations, and Quantized Organisms: Causality in complex organisms is sculpted by constraints rather than instigators, with outcomes perhaps better described by quantized patterns than rectilinear pathways. Bioessays 2020; 42:e1900135. [PMID: 32484248 PMCID: PMC7518294 DOI: 10.1002/bies.201900135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 03/19/2020] [Indexed: 12/22/2022]
Abstract
Complex organisms thwart the simple rectilinear causality paradigm of "necessary and sufficient," with its experimental strategy of "knock down and overexpress." This Essay organizes the eccentricities of biology into four categories that call for new mathematical approaches; recaps for the biologist the philosopher's recent refinements to the causation concept and the mathematician's computational tools that handle some but not all of the biological eccentricities; and describes overlooked insights that make causal properties of physical hierarchies such as emergence and downward causation straightforward. Reviewing and extrapolating from similar situations in physics, it is suggested that new mathematical tools for causation analysis incorporating feedback, signal cancellation, nonlinear dependencies, physical hierarchies, and fixed constraints rather than instigative changes will reveal unconventional biological behaviors. These include "eigenisms," organisms that are limited to quantized states; trajectories that steer a system such as an evolving species toward optimal states; and medical control via distributed "sheets" rather than single control points.
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Affiliation(s)
- Douglas E Brash
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, 06520-8040, USA
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4
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Xia Y, Wang L, Ma X, Li X. Investigation on the Genomic Characterization of Uterine Sarcoma for rAd- p53 Combined with Chemotherapy Treatment. Hum Gene Ther 2020; 31:881-890. [PMID: 32013587 DOI: 10.1089/hum.2019.305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The aim is to investigate the genomic characterization of uterine sarcoma for rAd-p53 (Gendicine®) combined with chemotherapy treatment. We recently published an article on 12 cases of uterine sarcomas, which were treated with rAd-p53 combined with chemotherapy. We found that rAd-p53 combined with chemotherapy is effective for various uterine sarcomas. Pretreatment pathological specimens of four uterine sarcoma patients were collected from the above recent clinical research and numbered 1-4A/B. Tumor samples were subjected to targeted sequencing by using a 416 genes panel. We profiled the mutation spectrum and tumor mutation burden in the tumors, identified mutated genes, and explored their gene function. We also verified the p53 protein expression using immunohistochemistry. We identified a total of 30 mutated genes that were found from the next-generation sequencing test results. The average number of mutated genes was up to seven in the five samples. TP53 gene was mutated in two of the four patients, No. 1 and No. 4B. They are c.C833G (p.P278R) missense mutation and a point mutation (C141*) that result in a premature stop codon. We did not find a mutated TP53 gene in the other two cases, but we identified mutated genes, including CREBBP, LYN, CDKN2A, and JAK2, which were located upstream of the TP53 gene; they may have an impact on TP53. We also identified 11 additional genes which are involved in p53-related signaling pathways or have interaction with p53. Compared to solid tumor mutational burden (TMB) distribution, none of their TMB was ranking in the top 25%. Mutant p53 protein expression was positive in two specimens. Our results demonstrated that the TP53 signaling pathway plays an important role in uterine sarcoma tumorigenesis. TP53 and the upstream genes such as CREBBP, LYN, CDKN2A, and JAK2 may be involved in the genomic characterization for rAd-p53 (Gendicine) combined with chemotherapy in uterine sarcoma. Besides, the average amount of mutated genes from every patient is large.
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Affiliation(s)
- Yu Xia
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Lei Wang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xiaolin Ma
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xiuqin Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
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5
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Liu X, Wang S, Guo X, Wei F, Yin J, Zang Y, Li N, Chen D. Exogenous p53 and ASPP2 expression enhances rAdV-TK/ GCV-induced death in hepatocellular carcinoma cells lacking functional p53. Oncotarget 2017; 7:18896-905. [PMID: 26934443 PMCID: PMC4951338 DOI: 10.18632/oncotarget.7749] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 01/13/2016] [Indexed: 12/13/2022] Open
Abstract
Suicide gene therapy using herpes simplex virus-1 thymidine kinase (HSV-TK) in combination with ganciclovir (GCV) has emerged as a potential new method for treating cancer. We hypothesize that the efficacy of HSV-TK/GCV therapy is at least partially dependent on p53 status in hepatocellular carcinoma (HCC) patients. Using recombinant adenoviral vectors (rAdV), TK, p53, and ASPP2 were overexpressed individually and in combination in Hep3B (p53 null) and HepG2 (p53 wild-type) cell lines and in primary HCC tumor cells. p53 overexpression induced death in Hep3B cells, but not HepG2 cells. ASPP2 overexpression increased rAdV-TK/GCV-induced HepG2 cell death by interacting with endogenous p53. Similarly, ASPP2 reduced survival in rAdV-TK/GCV-treated primary HCC cells expressing p53 wild-type but not a p53 R249S mutant. Mutated p53 was unable to bind to ASPP2, suggesting that the increase in rAdV-TK/GCV-induced cell death resulting from ASPP2 overexpression was dependent on its interaction with p53. Additionally, γ-H2AX foci, ATM phosphorylation, Bax, and p21 expression increased in rAdV-TK/GCV-treated HepG2 cells as compared to Hep3B cells. This suggests that the combined use of HSV-TK, GCV, rAdV-p53 and rAdV-ASPP2 may improve therapeutic efficacy in HCC patients lacking functional p53.
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Affiliation(s)
- Xiuhong Liu
- Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China.,Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
| | - Shuang Wang
- Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China.,Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
| | - Xianghua Guo
- Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
| | - Feili Wei
- Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
| | - Jiming Yin
- Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
| | - Yunjin Zang
- Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China
| | - Ning Li
- Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China
| | - Dexi Chen
- Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China.,Beijing Institute of Hepatology, Capital Medical University, Beijing 100069, China
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Abstract
Background: Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism. Objective: This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation. Methods: A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation. Results: It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation. Conclusion: Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.
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Affiliation(s)
- Jeffrey Chow
- Department of Laboratory Medicine and Pathology, 4B1.19 Walter C Mackenzie Health Science Centre, University of Alberta, 8440-112th Street, Edmonton, AB, CanadaT6G 2B7
| | - Victor A. Tron
- Department of Laboratory Medicine and Pathology, 4B1.19 Walter C Mackenzie Health Science Centre, University of Alberta, 8440-112th Street, Edmonton, AB, CanadaT6G 2B7
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7
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Zeng X, Zhao J, Wu X, Shi H, Liu W, Cui B, Yang L, Ding X, Song P. PageRank analysis reveals topologically expressed genes correspond to psoriasis and their functions are associated with apoptosis resistance. Mol Med Rep 2016; 13:3969-76. [PMID: 27035208 DOI: 10.3892/mmr.2016.4999] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 02/19/2016] [Indexed: 11/06/2022] Open
Abstract
Psoriasis is an inflammatory skin disease. Deceleration in keratinocyte apoptosis is the most significant pathological change observed in psoriasis. To detect a meaningful correlation between the genes and gene functions associated with the mechanism underlying psoriasis, 927 differentially expressed genes (DEGs) were identified using the Gene Expression Omnibus database, GSE13355 [false discovery rate (FDR) <0.01; |log fold change >1] with the package in R langue. The selected DEGs were further constructed using the search tool for the retrieval of interacting genes, in order to analyze the interaction network between the DEGs. Subsequent to PageRank analysis, 14 topological hub genes were identified, and the functions and pathways in the hub genes network were analyzed. The top‑ranked hub gene, estrogen receptor‑1 (ESR1) is downregulated in psoriasis, exhibited binding sites enriched with genes possessing anti‑apoptotic functions. The ESR1 gene encodes estrogen receptor α (ERα); a reduced level of ERα expression provides a crucial foundation in response to the anti‑apoptotic activity of psoriatic keratinocytes by activating the expression of anti‑apoptotic genes. Furthermore, it was detected that the pathway that is associated most significantly with psoriasis is the pathways in cancer. Pathways in cancer may protect psoriatic cells from apoptosis by inhibition of ESR1 expression. The present study provides support towards the investigation of ESR1 gene function and elucidates that the interaction with anti‑apoptotic genes is involved in the underlying biological mechanisms of resistance to apoptosis in psoriasis. However, further investigation is required to confirm the present results.
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Affiliation(s)
- Xue Zeng
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Jingjing Zhao
- Key Laboratory of Advanced Control and Optimization for Chemical Processes of the Ministry of Education, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Xiaohong Wu
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Hongbo Shi
- Key Laboratory of Advanced Control and Optimization for Chemical Processes of the Ministry of Education, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Wali Liu
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Bingnan Cui
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Li Yang
- Department of Otorhinolaryngology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Xu Ding
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
| | - Ping Song
- Department of Dermatology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 201203, P.R. China
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8
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Tang W, Xue R, Weng S, Wu J, Fang Y, Wang Y, Ji L, Hu T, Liu T, Huang X, Chen S, Shen X, Zhang S, Dong L. BIRC6 promotes hepatocellular carcinogenesis: interaction of BIRC6 with p53 facilitating p53 degradation. Int J Cancer 2014; 136:E475-87. [PMID: 25196217 DOI: 10.1002/ijc.29194] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 08/17/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022]
Abstract
The genes that encode inhibitor of apoptosis proteins (IAPs) are frequently overexpressed in human cancers. However, the expression pattern and clinical significance of BIRC6, a member of IAPs, in hepatocellular carcinoma (HCC) remains unclear. Here we investigated the role of BIRC6 in hepatocellular carcinogenesis. We used immunoblot and immunochemical analyses to determine the levels of BIRC6 in 7 hepatoma cell lines and 160 HCC specimens. We evaluated the proognostic value of BIRC6 expression and its association with clinical parameters. A lentivirus-mediated silencing method was used to knockdown BIRC6, and the biological consequences of BIRC6 silencing in three hepatoma cell lines were investigated in vitro and in vivo. We found that BIRC6 overexpression was significantly correlated with serum ALT level and HCC vascular invasion. Patients with positive BIRC6 expression in tumor tissue had a poor survival and a high rate of recurrence. BIRC6 knockdown remarkably suppressed cell proliferation, caused G1/S arrest and sensitized hepatoma cells to sorafenib-induced apoptosis in hepatoma cells, which was partly reversed by RNA interference targeting p53. The mechanistic study revealed that BIRC6 interacted with p53 and facilitated its degradation. The in vivo study showed that BIRC6 knockdown inhibited xenograft tumor growth and increased the sensitivity of tumor cells to sorafenib in nude mice. Taken together, these findings demonstrate that BIRC6 overexpression in HCC specimens is indicative of poor prognosis and that its interaction with p53 facilitates the degradation of p53, leading to carcinogenesis and an anti-apoptotic status.
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Affiliation(s)
- Wenqing Tang
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Shanghai, Institute of Liver Disease, Fudan University, Shanghai, China
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9
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Cordyceps militaris extract protects human dermal fibroblasts against oxidative stress-induced apoptosis and premature senescence. Nutrients 2014; 6:3711-26. [PMID: 25230212 PMCID: PMC4179184 DOI: 10.3390/nu6093711] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/30/2014] [Accepted: 08/29/2014] [Indexed: 11/30/2022] Open
Abstract
Oxidative stress induced by reactive oxygen species (ROS) is the major cause of degenerative disorders including aging and disease. In this study, we investigated whether Cordycepsmilitaris extract (CME) has in vitro protective effects on hydrogen peroxide-induced oxidative stress in human dermal fibroblasts (HDFs). Our results showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CME was increased in a dose-dependent manner. We found that hydrogen peroxide treatment in HDFs increased ROS generation and cell death as compared with the control. However, CME improved the survival of HDFs against hydrogen peroxide-induced oxidative stress via inhibition of intracellular ROS production. CME treatment inhibited hydrogen peroxide-induced apoptotic cell death and apoptotic nuclear condensation in HDFs. In addition, CME prevented hydrogen peroxide-induced SA-β-gal-positive cells suggesting CME could inhibit oxidative stress-induced premature senescence. Therefore, these results suggest that CME might have protective effects against oxidative stress-induced premature senescence via scavenging ROS.
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10
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Zbytek B, Peacock DL, Seagroves TN, Slominski A. Putative role of HIF transcriptional activity in melanocytes and melanoma biology. DERMATO-ENDOCRINOLOGY 2014; 5:239-51. [PMID: 24194964 PMCID: PMC3772912 DOI: 10.4161/derm.22678] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/23/2012] [Accepted: 10/26/2012] [Indexed: 12/30/2022]
Abstract
Hypoxia-inducible factor-1α (HIF-1α) is a highly oxygen sensitive bHLH protein that is part of the heterodimeric HIF-1 transcription factor. Under hypoxic stress, HIF-1 activity is induced to control expression of multiple downstream target genes, including vascular endothelial growth factor (VEGF). The normal epidermis exists in a constant mild hypoxic microenvironment and constitutively expresses HIF-1α and HIF-2α. Expression of HIF-1α and/or HIF-2α has been suggested to correlate with the increased malignant potential of melanocytes, therefore, failures of melanoma therapies may be partially linked to high HIF activity. Notably, melanomas that have the V600E BRAF mutation exhibit increased HIF-1α expression. We have utilized a bioinformatics approach to identify putative hypoxia response elements (HREs) in a set of genes known to participate in the process of melanogenesis (includingTRPM1, SLC45A2, HRAS, C-KIT, PMEL and CRH). While some of the mechanistic links between these genes and the HIF pathway have been previously explored, others await further investigation. Although agents targeting HIF activity have been proposed as novel treatment modalities for melanoma, there are currently no clinical trials in progress to test their efficacy in melanoma.
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Affiliation(s)
- Blazej Zbytek
- Department of Pathology and Laboratory Medicine; Center for Adult Cancer Research; University of Tennessee Health Science Center; Memphis, TN USA
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11
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Huang CM, Xu H, Wang CC, Elmets CA. Proteomic characterization of skin and epidermis in response to environmental agents. Expert Rev Proteomics 2014; 2:809-20. [PMID: 16209658 DOI: 10.1586/14789450.2.5.809] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The skin and its outer epidermis layer in particular, prevent access of various environmental agents including potential allergens, irritants, carcinogens, ultraviolet radiation and microbes. Cells in the epidermis make a significant contribution to innate as well as adaptive immune reactions in skin. The skin immunity thus provides a biologic defense in response to hazardous environmental agents. Although proteomics has been utilized to establish skin proteomes and investigate skin responses to some environmental agents, it has not been extensively used to address the complexity of skin responses to various environments. This review summarizes cutaneous genes and proteins that have been characterized as related to skin exposure to environmental agents. In parallel, this review emphasizes functional proteomics and systems biology, which are believed to be an important future direction toward characterizing the skin proteome-environmental interaction and developing successful therapeutic strategies for skin diseases caused by environmental insults.
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Affiliation(s)
- Chun-Ming Huang
- Department of Dermatology, Skin Diseases Research Center, University of Alabama, Birmingham, AL 35294-0019, USA.
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12
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p53-dependent regulation of Mcl-1 contributes to synergistic cell death by ionizing radiation and the Bcl-2/Bcl-XL inhibitor ABT-737. Apoptosis 2012; 17:187-99. [PMID: 22002102 DOI: 10.1007/s10495-011-0664-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Treatment with the Bcl-2/Bcl-XL inhibitor ABT-737 is a promising novel strategy to therapeutically induce apoptotic cell death in malignant tumors such as glioblastomas. Although many studies have demonstrated that ABT-737 acts synergistically with chemotherapeutic drugs, the possibility of a combined treatment with ionizing radiation (IR) and ABT-737 has not yet been thoroughly investigated. Similarly, the relationship between p53 function and the pro-apoptotic effects of ABT-737 are still obscure. Here, we demonstrate that IR and ABT-737 synergistically induce apoptosis in glioblastoma cells. The sensitivity to ABT-737-mediated cell death is significantly increased by the IR-dependent accumulation of cells in the G2/M cell cycle phase. Wild type p53 function inhibits the efficacy of a combined IR and ABT-737 treatment via a p21-dependent G1 cell cycle arrest. Moreover, mutant as well as wild type p53 counteract the pro-apoptotic activity of ABT-737 by maintaining the expression levels of the Mcl-1 protein. Thus, p53 regulates the sensitivity to ABT-737 of glioblastoma cells. Our results warrant a further evaluation of a novel combination therapy using IR and ABT-737. The efficacy of such a therapy could be substantially enhanced by Mcl-1-lowering strategies.
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13
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Nys K, Agostinis P. Bcl-2 family members: essential players in skin cancer. Cancer Lett 2012; 320:1-13. [PMID: 22281242 DOI: 10.1016/j.canlet.2012.01.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/17/2012] [Accepted: 01/18/2012] [Indexed: 12/11/2022]
Abstract
Skin cancer has reached epidemic proportions and is considered to be a direct consequence of ultraviolet (UV) radiation exposure. Excessive exposure of epidermal cells to UV results in apoptosis of irreparably damaged cells to avoid malignant transformation. The Bcl-2 family of proteins is emerging as a crucial regulator of epidermal homeostasis and cell's fate in the stressed skin. Not surprisingly, deregulation of Bcl-2 family members is also chiefly involved in skin carcinogenesis and response to cancer therapy. Here we discuss the physiopathological role of epidermal Bcl-2 family members, their implications in skin carcinogenesis and as potential targets in cancer therapy.
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Affiliation(s)
- Kris Nys
- Cell Death Research & Therapy Unit, Department for Molecular Cell Biology, Catholic University of Leuven, Leuven, Belgium
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14
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Farrell AW, Halliday GM, Lyons JG. Chromatin structure following UV-induced DNA damage-repair or death? Int J Mol Sci 2011; 12:8063-85. [PMID: 22174650 PMCID: PMC3233456 DOI: 10.3390/ijms12118063] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 10/05/2011] [Accepted: 10/31/2011] [Indexed: 12/15/2022] Open
Abstract
In eukaryotes, DNA is compacted into a complex structure known as chromatin. The unravelling of DNA is a crucial step in DNA repair, replication, transcription and recombination as this allows access to DNA for these processes. Failure to package DNA into the nucleosome, the individual unit of chromatin, can lead to genomic instability, driving a cell into apoptosis, senescence, or cellular proliferation. Ultraviolet (UV) radiation damage causes destabilisation of chromatin integrity. UV irradiation induces DNA damage such as photolesions and subjects the chromatin to substantial rearrangements, causing the arrest of transcription forks and cell cycle arrest. Highly conserved processes known as nucleotide and base excision repair (NER and BER) then begin to repair these lesions. However, if DNA repair fails, the cell may be forced into apoptosis. The modification of various histones as well as nucleosome remodelling via ATP-dependent chromatin remodelling complexes are required not only to repair these UV-induced DNA lesions, but also for apoptosis signalling. Histone modifications and nucleosome remodelling in response to UV also lead to the recruitment of various repair and pro-apoptotic proteins. Thus, the way in which a cell responds to UV irradiation via these modifications is important in determining its fate. Failure of these DNA damage response steps can lead to cellular proliferation and oncogenic development, causing skin cancer, hence these chromatin changes are critical for a proper response to UV-induced injury.
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Affiliation(s)
- Andrew W Farrell
- Discipline of Dermatology, Bosch Institute, Sydney Cancer Centre, The University of Sydney, NSW 2006, Australia; E-Mails: (A.W.F.); (J.G.L.)
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Avery-Kiejda KA, Bowden NA, Croft AJ, Scurr LL, Kairupan CF, Ashton KA, Talseth-Palmer BA, Rizos H, Zhang XD, Scott RJ, Hersey P. P53 in human melanoma fails to regulate target genes associated with apoptosis and the cell cycle and may contribute to proliferation. BMC Cancer 2011; 11:203. [PMID: 21615965 PMCID: PMC3120805 DOI: 10.1186/1471-2407-11-203] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 05/27/2011] [Indexed: 12/29/2022] Open
Abstract
Background Metastatic melanoma represents a major clinical problem. Its incidence continues to rise in western countries and there are currently no curative treatments. While mutation of the P53 tumour suppressor gene is a common feature of many types of cancer, mutational inactivation of P53 in melanoma is uncommon; however, its function often appears abnormal. Methods In this study whole genome bead arrays were used to examine the transcript expression of P53 target genes in extracts from 82 melanoma metastases and 6 melanoma cell lines, to provide a global assessment of aberrant P53 function. The expression of these genes was also examined in extracts derived from diploid human melanocytes and fibroblasts. Results The results indicated that P53 target transcripts involved in apoptosis were under-expressed in melanoma metastases and melanoma cell lines, while those involved in the cell cycle were over-expressed in melanoma cell lines. There was little difference in the transcript expression of P53 target genes between cell lines with null/mutant P53 compared to those with wild-type P53, suggesting that altered expression in melanoma was not related to P53 status. Similarly, down-regulation of P53 by short-hairpin RNA (shRNA) had limited effect on P53 target gene expression in melanoma cells, whereas there were a large number of P53 target genes whose mRNA expression was significantly altered by P53 inhibition in melanocytes. Analysis of whole genome gene expression profiles indicated that the ability of P53 to regulate genes involved in the cell cycle was significantly reduced in melanoma cells. Moreover, inhibition of P53 in melanocytes induced changes in gene expression profiles that were characteristic of melanoma cells and resulted in increased proliferation. Conversely, knockdown of P53 in melanoma cells resulted in decreased proliferation. Conclusions These results indicate that P53 target genes involved in apoptosis and cell cycle regulation are aberrantly expressed in melanoma and that this aberrant functional activity of P53 may contribute to the proliferation of melanoma.
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Affiliation(s)
- Kelly A Avery-Kiejda
- Oncology and Immunology, Calvary Mater Newcastle Hospital, University of Newcastle, Newcastle, NSW, Australia
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Nys K, Maes H, Dudek AM, Agostinis P. Uncovering the role of hypoxia inducible factor-1α in skin carcinogenesis. Biochim Biophys Acta Rev Cancer 2011; 1816:1-12. [PMID: 21338656 DOI: 10.1016/j.bbcan.2011.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 02/08/2011] [Accepted: 02/11/2011] [Indexed: 01/02/2023]
Abstract
The hypoxia inducible factor-1α (HIF-1α) is a pleiotropic transcription factor typically activated in response to low oxygen tension as well as other stress factors in normoxic conditions. Upon activation HIF-1α mediates the transcriptional activation of target genes involved in a variety of processes comprising stress adaptation, metabolism, growth and invasion, but also apoptotic cell death. The molecular mechanisms, signaling pathways and downstream targets evoked by the activation of HIF-1α in epidermal cells are becoming increasingly understood and underscore the participation of HIF-1α in crucial processes including malignant transformation and cancer progression. Recent studies have implicated HIF-1α as an integral part of the multifaceted signal transduction initiated by the exposure of keratinocytes to ultraviolet radiation B (UVB), which represents the most ubiquitous hazard for human skin and the principal risk factor for skin cancer. HIF-1α activation by UVB exposure contributes to either repair or the removal of UVB-damaged keratinocytes by inducing apoptosis, thus revealing a tumor suppressor role for HIF-1α in these cells. On the other hand, the constitutive expression of HIF-1α evoked by the mild hypoxic state of the skin has been implicated as a positive factor in the transformation of normal melanocytes into malignant melanoma, one of the most aggressive types of human cancers. Here we review the uncovered and complex role of HIF-1α in skin carcinogenesis.
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Affiliation(s)
- Kris Nys
- Cell Death Research & Therapy Laboratory, Department Molecular and Cell Biology, Faculty of Medicine, Catholic University of Leuven, Herestroat 49, box 901, B-3000, Belgium
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Cimica V, Smith ME, Zhang Z, Mathur D, Mani S, Kalpana GV. Potent inhibition of rhabdoid tumor cells by combination of flavopiridol and 4OH-tamoxifen. BMC Cancer 2010; 10:634. [PMID: 21092078 PMCID: PMC2998513 DOI: 10.1186/1471-2407-10-634] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 11/19/2010] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Rhabdoid Tumors (RTs) are highly aggressive pediatric malignancies with poor prognosis. There are currently no standard or effective treatments for RTs in part because treatments are not designed to specifically target these tumors. Our previous studies indicated that targeting the cyclin/cdk pathway is a novel therapeutic strategy for RTs and that a pan-cdk inhibitor, flavopiridol, inhibits RT growth. Since the toxicities and narrow window of activity associated with flavopiridol may limit its clinical use, we tested the effect of combining flavopiridol with 4-hydroxy-Tamoxifen (4OH-Tam) in order to reduce the concentration of flavopiridol needed for inhibition of RTs. METHODS The effects of flavopiridol, 4OH-Tam, and their combination on RT cell cycle regulation and apoptosis were assessed by: i) cell survival assays, ii) FACS analysis, iii) caspase activity assays, and iv) immunoblot analysis. Furthermore, the role of p53 in flavopiridol- and 4OH-Tam-mediated induction of cell cycle arrest and apoptosis was characterized using RNA interference (siRNA) analysis. The effect of p53 on flavopiridol-mediated induction of caspases 2, 3, 8 and 9 was also determined. RESULTS We found that the combination of flavopiridol and 4OH-Tam potently inhibited the growth of RT cells. Low nanomolar concentrations of flavopiridol induced G₂ arrest, which was correlated to down-modulation of cyclin B1 and up-regulation of p53. Addition of 4OH-Tam did not affect flavopiridol-mediated G₂ arrest, but enhanced caspase 3,7-mediated apoptosis induced by the drug. Abrogation of p53 by siRNA abolished flavopiridol-induced G₂ arrest, but enhanced flavopiridol- (but not 4OH-Tam-) mediated apoptosis, by enhancing caspase 2 and 3 activities. CONCLUSIONS Combining flavopiridol with 4OH-Tam potently inhibited the growth of RT cells by increasing the ability of either drug alone to induce caspases 2 and 3 thereby causing apoptosis. The potency of flavopiridol was enhanced by abrogation of p53. Our results warrant further studies investigating the combinatorial effects of flavopiridol and 4OH-Tam as a novel therapeutic strategy for RTs and other tumors that have been shown to respond to flavopiridol.
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Affiliation(s)
- Velasco Cimica
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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18
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Rodenberg JM, Hoggatt AM, Chen M, Touw K, Jones R, Herring BP. Regulation of serum response factor activity and smooth muscle cell apoptosis by chromodomain helicase DNA-binding protein 8. Am J Physiol Cell Physiol 2010; 299:C1058-67. [PMID: 20739623 DOI: 10.1152/ajpcell.00080.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serum response factor (SRF) is a widely expressed protein that plays a key role in the regulation of smooth muscle differentiation, proliferation, migration, and apoptosis. It is generally accepted that one mechanism by which SRF regulates these diverse functions is through pathway-specific cofactor interactions. A novel SRF cofactor, chromodomain helicase DNA binding protein 8 (CHD8), was isolated from a yeast two-hybrid screen using SRF as bait. CHD8 is highly expressed in adult smooth muscle tissues. Coimmunoprecipitation assays from A10 smooth muscle cells demonstrated binding of endogenous SRF and CHD8. Data from GST-pulldown assays indicate that the NH(2)-terminus of CHD8 can interact directly with the MADS domain of SRF. Adenoviral-mediated knockdown of CHD8 in smooth muscle cells resulted in attenuated expression of SRF-dependent, smooth muscle-specific genes. Knockdown of CHD8, SRF, or CTCF, a previously described binding partner of CHD8, in A10 VSMCs also resulted in a marked induction of apoptosis. Mechanistically, apoptosis induced by CHD8 knockdown was accompanied by attenuated expression of the anti-apoptotic proteins, Birc5, and CARD10, whereas SRF knockdown attenuated expression of CARD10 and Mcl-1, but not Birc5, and CTCF knockdown attenuated expression of Birc5. These data suggest that CHD8 plays a dual role in smooth muscle cells modulating SRF activity toward differentiation genes and promoting cell survival through interactions with both SRF and CTCF to regulate expression of Birc5 and CARD10.
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Affiliation(s)
- Jennifer M Rodenberg
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5120, USA
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19
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Ikehata H, Okuyama R, Ogawa E, Nakamura S, Usami A, Mori T, Tanaka K, Aiba S, Ono T. Influences of p53 deficiency on the apoptotic response, DNA damage removal and mutagenesis in UVB-exposed mouse skin. Mutagenesis 2010; 25:397-405. [DOI: 10.1093/mutage/geq019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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A p38(MAPK)/HIF-1 pathway initiated by UVB irradiation is required to induce Noxa and apoptosis of human keratinocytes. J Invest Dermatol 2010; 130:2269-76. [PMID: 20393480 DOI: 10.1038/jid.2010.93] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The signal transduction pathways leading to apoptosis of human keratinocytes responding to UVB irradiation are complex and not completely understood. Previously, we reported that in UVB-irradiated keratinocytes, p38(MAPK) instigates Bcl-2-associated X protein (Bax) activation and mitochondrial apoptosis. However, the molecular mechanism underlying the pro-apoptotic function of p38(MAPK) remained unclear. Here, we show that in UVB-treated human primary keratinocytes the activation of p38(MAPK) is necessary to upregulate Noxa, a BH3-only pro-apoptotic dominantly induced by UVB and required for apoptosis. Whereas p53-silencing was marginally cytoprotective and poorly affected Noxa expression, p38(MAPK) inhibition in p53-silenced keratinocytes or in p53(-/-) cells could still efficiently prevent Noxa induction and intrinsic apoptosis after UVB, indicating that p38(MAPK) signals mainly through p53-independent mechanisms. Furthermore, p38(MAPK) was required for the induction and activation of hypoxia-inducible factor 1 (HIF-1) in response to UVB, and HIF-1 knockdown reduced Noxa expression and apoptosis. In UVB-irradiated keratinocytes, Noxa targeted the anti-apoptotic myeloid cell leukemia sequence 1 (Mcl-1) for degradation, and small-interfering RNA (siRNA)-mediated knockdown of Noxa or p38(MAPK) inhibition restored levels of Mcl-1 and abolished apoptosis. Thus, the pro-apoptotic mechanisms orchestrated by p38(MAPK) in human keratinocytes in response to UVB involve an HIF-1/Noxa axis, which prompts the downregulation of anti-apoptotic Mcl-1, thereby favoring Bax-mediated mitochondrial apoptosis of UVB-damaged keratinocytes.
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21
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Ruff AL, Dillman JF. Sulfur mustard induced cytokine production and cell death: Investigating the potential roles of the p38, p53, and NF-κB signaling pathways with RNA interference. J Biochem Mol Toxicol 2010; 24:155-64. [DOI: 10.1002/jbt.20321] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Ibuki Y, Akaike M, Toyooka T. PI3-kinase/Akt Pathway Mediates Expression of p53 after UVB Irradiation. Genes Environ 2010. [DOI: 10.3123/jemsge.32.85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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23
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Hattori N, Mochizuki S, Kishi K, Nakajima T, Takaishi H, D'Armiento J, Okada Y. MMP-13 plays a role in keratinocyte migration, angiogenesis, and contraction in mouse skin wound healing. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:533-46. [PMID: 19590036 DOI: 10.2353/ajpath.2009.081080] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Matrix metalloproteinases (MMPs) have been implicated in wound healing. To analyze the roles of MMP-9 and MMP-13 in wound healing, we generated full-thickness cutaneous wounds in MMP-9 knockout (KO), MMP-13 KO, MMP-9/13 double KO, and wild-type mice. Macroscopic wound closure was delayed in all of the KO mice, as compared with wild-type mice. The rate of re-epithelialization was significantly delayed in MMP-9 KO and MMP-13 KO mice and remarkably delayed in MMP-9/13 double KO mice, as compared with wild-type mice. Both MMP-9 and MMP-13 were expressed by the leading edges of epidermal cells in wild-type mice, and the migration of keratinocytes was suppressed by treatment with an MMP inhibitor or transfection of small interfering RNAs for MMP-9 or MMP-13, as compared with controls. The vascular density in wound granulation was significantly lower in both MMP-13 KO and MMP-9/13 double KO mice than in wild-type mice. Degradation of connective tissue growth factor in wound tissue was transiently prevented in MMP-13 KO mice. Morphometric analyses demonstrated a reduction in both wound contraction and myofibroblast formation in both MMP-13 KO and MMP-9/13 double KO mice. Proliferation and transforming growth factor-beta1-induced myofibroblast differentiation of dermal fibroblasts from MMP-13 KO mice were decreased, as compared with wild-type dermal fibroblasts. These data suggest that MMP-13 plays a role in keratinocyte migration, angiogenesis, and contraction in wound healing, while MMP-9 functions in keratinocyte migration.
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Affiliation(s)
- Noriko Hattori
- Department of Pathology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-0016, Japan
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24
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Mcl-1 functions as major epidermal survival protein required for proper keratinocyte differentiation. J Invest Dermatol 2009; 129:1351-60. [PMID: 19037233 DOI: 10.1038/jid.2008.363] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rapid downregulation of the antiapoptotic Bcl-2 family protein myeloid cell leukemia 1 (Mcl-1) is required for UV-induced apoptosis, underlining an important role for Mcl-1 in epidermal pathology. To determine if Mcl-1 has a specific role in normal keratinocyte (KC) biology, Mcl-1 was downregulated in human KCs by RNAi and these KCs were induced to differentiate in organotypic raft cultures. Mcl-1 shRNA organotypic cultures showed increased levels of spontaneous premature apoptosis, implicating Mcl-1 as an essential KC survival protein. Mcl-1-downregulated cultures also had reduced granular and cornified layers, and produced lower levels of cross-linked protein and cornified envelopes. Cornification could only partially be rescued with the general caspase inhibitor z-VAD, suggesting that reduced cornification was not entirely because of premature apoptosis. Differentiation markers (K1, K10, filaggrin, loricrin, cleaved caspase-14) were normally expressed in control organotypic cultures, but were expressed at reduced levels in organotypic cultures with downregulated Mcl-1. The defect in differentiation marker expression was independent of apoptosis as it could not be rescued by z-VAD. Thus, Mcl-1 serves two important, independent functions in epidermal KCs: acting as a major survival protein by inhibiting premature apoptosis in the spinous and granular layers to promote conification, and promoting the robust induction of KC differentiation markers.
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25
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Batista LFZ, Roos WP, Kaina B, Menck CFM. p53 mutant human glioma cells are sensitive to UV-C-induced apoptosis due to impaired cyclobutane pyrimidine dimer removal. Mol Cancer Res 2009; 7:237-46. [PMID: 19208740 DOI: 10.1158/1541-7786.mcr-08-0428] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The p53 protein is a key regulator of cell responses to DNA damage, and it has been shown that it sensitizes glioma cells to the alkylating agent temozolomide by up-regulating the extrinsic apoptotic pathway, whereas it increases the resistance to chloroethylating agents, such as ACNU and BCNU, probably by enhancing the efficiency of DNA repair. However, because these agents induce a wide variety of distinct DNA lesions, the direct importance of DNA repair is hard to access. Here, it is shown that the induction of photoproducts by UV light (UV-C) significantly induces apoptosis in a p53-mutated glioma background. This is caused by a reduced level of photoproduct repair, resulting in the persistence of DNA lesions in p53-mutated glioma cells. UV-C-induced apoptosis in p53 mutant glioma cells is preceded by strong transcription and replication inhibition due to blockage by unrepaired photolesions. Moreover, the results indicate that UV-C-induced apoptosis of p53 mutant glioma cells is executed through the intrinsic apoptotic pathway, with Bcl-2 degradation and sustained Bax and Bak up-regulation. Collectively, the data indicate that unrepaired DNA lesions induce apoptosis in p53 mutant gliomas despite the resistance of these gliomas to temozolomide, suggesting that efficiency of treatment of p53 mutant gliomas might be higher with agents that induce the formation of DNA lesions whose global genomic repair is dependent on p53.
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Affiliation(s)
- Luis F Z Batista
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP 05508-900, Brazil
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26
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Lewis DA, Travers JB, Spandau DF. A new paradigm for the role of aging in the development of skin cancer. J Invest Dermatol 2008; 129:787-91. [PMID: 18818672 DOI: 10.1038/jid.2008.293] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Pietrzak M, Puzianowska-Kuznicka M. p53-dependent repression of the human MCL-1 gene encoding an anti-apoptotic member of the BCL-2 family: the role of Sp1 and of basic transcription factor binding sites in the MCL-1 promoter. Biol Chem 2008; 389:383-93. [PMID: 18208354 DOI: 10.1515/bc.2008.039] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
p53 regulates transcription of one anti-apoptotic and four pro-apoptotic members of the BCL-2 family, but nothing is known about the regulation of MCL-1, another antiapoptotic member of this family, by p53. Confocal microscopic analysis of COS1, HEK 293 and HeLa cells transfected with a p53 expression plasmid demonstrated a decrease in the signal of endogenous MCL-1 compared to neighboring non-transfected cells. Transcription regulation assays showed that the 1826 bp human MCL-1 promoter fragment was repressed up to 30-fold by wild-type p53 in a dose-dependent manner. As shown by electrophoretic mobility shift assays, Sp1 binding to the sites located in the -295 to +16 MCL-1 promoter fragment was decreased in the presence of p53. However, the MCL-1 promoter devoid of all Sp1 binding sites was still repressed by p53, albeit 2-fold weaker than the wild-type promoter. Overexpression of Sp1 reduced p53-dependent repression of the MCL-1 promoter only up to 2.2-fold. Transcription regulation assays performed with MCL-1 promoter deletion mutants showed that most of the p53 inhibitory effect was mediated by the -41 to +16 bp promoter fragment containing binding sites only for TATA-binding protein and other basal transcription factors. We propose a novel, promoter-based mechanism by which p53 down-regulates expression of the antiapoptotic MCL-1 protein.
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Affiliation(s)
- Maciej Pietrzak
- Department of Endocrinology, Medical Research Center, Polish Academy of Sciences, 02-106 Warsaw, Poland
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28
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Shoemaker AR, Mitten MJ, Adickes J, Ackler S, Refici M, Ferguson D, Oleksijew A, O'Connor JM, Wang B, Frost DJ, Bauch J, Marsh K, Tahir SK, Yang X, Tse C, Fesik SW, Rosenberg SH, Elmore SW. Activity of the Bcl-2 family inhibitor ABT-263 in a panel of small cell lung cancer xenograft models. Clin Cancer Res 2008; 14:3268-77. [PMID: 18519752 DOI: 10.1158/1078-0432.ccr-07-4622] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of this study was to characterize the activity of the Bcl-2 protein family inhibitor ABT-263 in a panel of small cell lung cancer (SCLC) xenograft models. EXPERIMENTAL DESIGN A panel of 11 SCLC xenograft models was established to evaluate the efficacy of ABT-263. Single agent activity was examined on a continuous dosing schedule in each of these models. The H146 model was used to further evaluate dose and schedule, comparison to standard cytotoxic agents, and induction of apoptosis. RESULTS ABT-263 exhibited a range of antitumor activity, leading to complete tumor regression in several models. Significant regressions of tumors as large as 1 cc were also observed. The efficacy of ABT-263 was also quite durable; in several cases, minimal tumor regrowth was noted several weeks after the cessation of treatment. Antitumor effects were equal or superior to that of several clinically approved cytotoxic agents. Regression of large established tumors was observed through several cycles of therapy and efficacy was retained in a Pgp-1 overexpressing line. Significant efficacy was observed on several dose and therapeutic schedules and was associated with significant induction of apoptosis. CONCLUSIONS ABT-263 is a potent, orally bioavailable inhibitor of Bcl-2 family proteins that has recently entered clinical trials. The efficacy data reported here suggest that SCLC is a promising area of clinical investigation with this agent.
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Affiliation(s)
- Alex R Shoemaker
- Global Pharmaceutical Research and Development, Abbott, Abbott Park, IL, USA.
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Leverkus M, Diessenbacher P, Geserick P. FLIP ing the coin? Death receptor-mediated signals during skin tumorigenesis. Exp Dermatol 2008; 17:614-22. [PMID: 18558995 DOI: 10.1111/j.1600-0625.2008.00728.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Keratinocyte skin cancer is a multi-step process, during which a number of obstacles have to be overcome by the tumor cell to allow the development of a manifest tumor. Beside proliferation and immortality, apoptosis resistance is one additional and critical step during skin carcinogenesis. Over the past two decades, much has been learned about the prototypical membrane-bound inducers of apoptosis, namely the death receptors and their ligands, and the apoptosis signalling pathways activated by death receptors have been elucidated in great detail. In contrast, much less is known about the tissue-specific role of the death receptor/ligands systems during the development of skin cancer. Here, we summarize and discuss the role of this intriguing receptor family and the potential mechanistical impact of the intracellular caspase-8 inhibitor cFLIP for keratinocyte skin cancer. Given more recent data about cFLIP and its isoforms, a more complex regulatory role of cFLIP can be suspected. Indeed, cFLIP may not solely interfere with death receptor-mediated apoptosis signalling pathways, but may positively or negatively influence other, potential harmful signalling pathways such as the production of inflammatory cytokines, tumor cell migration or the activation of transcription factors such as NF-kappaB, considered crucial during skin tumorigenesis. In this respect, cFLIP may act to 'FLIP the coin' during the development of keratinocyte skin cancer.
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Affiliation(s)
- Martin Leverkus
- Department of Dermatology and Venerology, Laboratory for Experimental Dermatology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
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30
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Zeidan YH, Wu BX, Jenkins RW, Obeid LM, Hannun YA. A novel role for protein kinase Cdelta-mediated phosphorylation of acid sphingomyelinase in UV light-induced mitochondrial injury. FASEB J 2007; 22:183-93. [PMID: 17698617 DOI: 10.1096/fj.07-8967com] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Multiple studies have addressed the mechanisms by which ultraviolet (UV) light induces cell death, and a few have focused on stress mediators such as acid sphingomyelinase (ASMase) or protein kinase Cdelta (PKCdelta). Based on a recent study that identified a novel mechanism of activation of ASMase through phosphorylation, the current study was undertaken to determine the upstream mechanisms regulating ASMase in response to UV and to investigate the role of ASMase and its phosphorylation at S508 as an integral event during UV light-induced cell death. Exposure of MCF-7 breast cancer cells to UV light type C (UVC) transiently activated ASMase with maximal activity detected at 10 min postirradiation. A significant increase in C16-ceramide was detected concomitant with a decrease in C16-sphingomyelin. In marked contrast, cells overexpressing the ASMase(S508A) mutant, which could not be phosphorylated, had no change in either ASMase activity or ceramide levels post-UV radiation. Loss of PKCdelta by RNA interference or its inhibition by rottlerin blocked ASMase phosphorylation and membrane targeting, thus implicating PKCdelta upstream of ASMase activation by UV light. Further investigations revealed that UV radiation altered mitochondrial morphology from elongated tubules to fragmented perinuclear organelles, consistent with the onset of the apoptotic cascade. Importantly, cells overexpressing ASMase(S508A) were protected (>50%) from UV light-induced mitochondrial fragmentation. Mechanistically, the results showed that ASMase(S508A) cells had 50% less active Bax than ASMase(WT) cells. These molecular differences culminated in resistance of ASMase(S508) cells to UVC-induced cell death (25%) as compared to ASMase(WT) cells (46%). Taken together, this study provides key molecular insights into activation of ASMase in response to UV light, the role of PKCdelta in this activation, and the role of ASMase in mediating apoptotic responses.
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Affiliation(s)
- Youssef H Zeidan
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
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31
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Derheimer FA, O'Hagan HM, Krueger HM, Hanasoge S, Paulsen MT, Ljungman M. RPA and ATR link transcriptional stress to p53. Proc Natl Acad Sci U S A 2007; 104:12778-83. [PMID: 17616578 PMCID: PMC1937543 DOI: 10.1073/pnas.0705317104] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanisms by which DNA-damaging agents trigger the induction of the stress response protein p53 are poorly understood but may involve alterations of chromatin structure or blockage of either transcription or replication. Here we show that transcription-blocking agents can induce phosphorylation of the Ser-15 site of p53 in a replication-independent manner. Furthermore, microinjection of anti-RNA polymerase II antibodies into the nuclei of cells showed that blockage of transcription is sufficient for p53 accumulation even in the absence of DNA damage. This induction of p53 occurs by two independent mechanisms. First, accumulation of p53 is linked to diminished nuclear export of mRNA; and second, inhibition specifically of elongating RNA polymerase II complexes results in the phosphorylation of the Ser-15 site of p53 in a replication protein A (RPA)- and ATM and Rad3-related (ATR)-dependent manner. We propose that this transcription-based stress response involving RPA, ATR, and p53 has evolved as a DNA damage-sensing mechanism to safeguard cells against DNA damage-induced mutagenesis.
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Affiliation(s)
- Frederick A. Derheimer
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
- Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI 48109; and
| | - Heather M. O'Hagan
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
- Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI 48109; and
| | - Heather M. Krueger
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
- Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI 48109; and
| | - Sheela Hanasoge
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
- Program in Toxicology, Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109
| | - Michelle T. Paulsen
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
| | - Mats Ljungman
- *Department of Radiation Oncology, Division of Radiation and Cancer Biology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-2200
- Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI 48109; and
- Program in Toxicology, Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109
- To whom correspondence should be addressed at:
University of Michigan Comprehensive Cancer Center, 2069 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200. E-mail:
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Kuo WHW, Wang Y, Wong RPC, Campos EI, Li G. The ING1b tumor suppressor facilitates nucleotide excision repair by promoting chromatin accessibility to XPA. Exp Cell Res 2007; 313:1628-38. [PMID: 17379210 DOI: 10.1016/j.yexcr.2007.02.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 02/03/2007] [Accepted: 02/12/2007] [Indexed: 11/15/2022]
Abstract
ING1b is the most studied ING family protein and perhaps the most ubiquitously and abundantly expressed. This protein is involved in the regulation of various biological functions ranging from senescence, cell cycle arrest, apoptosis, to DNA repair. ING1b is upregulated by UV irradiation and enhances the removal of bulky nucleic acid photoproducts. In this study, we provide evidence that ING1b mediates nucleotide excision repair by facilitating the access to damaged nucleosomal DNA. We demonstrate that ING1b is not recruited to UV-induced DNA lesions but enhances nucleotide excision repair only in XPC-proficient cells, implying an essential role in early steps of the 'access, repair, restore' model. We also find that ING1b alters histone acetylation dynamics upon exposure to UV radiation and induces chromatin relaxation in microccocal nuclease digestion assay, revealing that ING1b may allow better access to nucleotide excision repair machinery. More importantly, ING1b associates with chromatin in a UV-inducible manner and facilitates DNA access to nucleotide excision repair factor XPA. Furthermore, depletion of the endogenous ING1b results to the sensitization of cells at S-phase to UV irradiation. Taken together, these observations establish a role of ING1b acting as a chromatin accessibility factor for DNA damage recognition proteins upon genotoxic injury.
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Affiliation(s)
- Wei-Hung W Kuo
- Department of Dermatology and Skin Science, Jack Bell Research Centre, Vancouver Coastal Health Research Institute, The University of British Columbia, Vancouver, Canada BC V6H 3Z6
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Zhu L, Rorke EA, Eckert RL. DeltaNp63alpha promotes apoptosis of human epidermal keratinocytes. J Invest Dermatol 2007; 127:1980-91. [PMID: 17392828 DOI: 10.1038/sj.jid.5700797] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this study we show that deltaNp63alpha overexpression in primary human epidermal keratinocytes causes decreased cell proliferation and increased apoptosis. These changes are associated with increased levels of p21 and p27, decreased cyclin D1 and cyclin E levels, reduced mitochondrial membrane potential, and enhanced procaspase and poly(ADP-ribose) polymerase cleavage. Bcl-xS and Bax levels are increased and Bcl-xL level is reduced. p53 levels are increased in the deltaNp63alpha-expressing cells and p53 overexpression reproduces features of the deltaNp63alpha phenotype. Increased p53 expression results in reduced deltaNp63alpha, suggesting that p53 may negatively regulate deltaNp63alpha level. DeltaNp63alpha also induces apoptosis in HaCaT and SCC-13 cells, which encode inactive p53 genes, suggesting that the response is p53 independent in these cell lines. Both deltaNp63alpha and TAp63alpha reduce SCC-13 cell survival. These studies indicate that both deltaNp63alpha and TAp63alpha can negatively regulate keratinocyte survival.
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Affiliation(s)
- Ling Zhu
- Department of Physiology and Biophysics, Case School of Medicine, Cleveland, Ohio, USA
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Kraft CA, Efimova T, Eckert RL. Activation of PKCδ and p38δ MAPK during okadaic acid dependent keratinocyte apoptosis. Arch Dermatol Res 2007; 299:71-83. [PMID: 17256148 DOI: 10.1007/s00403-006-0727-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 10/18/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
There is substantial interest in identifying agents that differentially activate keratinocyte differentiation versus apoptosis. Okadaic acid (OA) is a tumor promoter in mouse skin that also stimulates apoptosis of murine keratinocytes. OA also enhances human keratinocyte differentiation; however, the impact of OA treatment on apoptosis in these cells has not been examined. We show that OA promotes normal human keratinocyte apoptosis as evidenced by increased accumulation of cells having sub-G1/S DNA content, decreased mitochondrial integrity, increased annexin V binding, increased cytoplasmic cytochrome c level, and increased procaspase 3 and PARP cleavage. Cyclin A, cyclin D1, cdk2, cdk4, p53 and p21 levels are reduced. These changes are associated with release of the PKCdelta catalytic domain and increased phosphorylation of PKCdelta-T(505)-responses consistent with PKCdelta activation. In contrast, phosphorylation of PKCdelta-Y(311) is not increased. The apoptotic response is enhanced in OA treated cells in the presence of p38delta, a PKCdelta target. OA treatment selectively activated p38delta, and OA-dependent apoptosis is not inhibited by treatment with the p38alpha/beta inhibitor, SB203580. These findings are consistent with the idea that the response is mediated by p38delta. Our data indicate that OA is an agent that regulates both keratinocyte differentiation and apoptosis, and that this regulation is mediated via activation of a PKCdelta/p38delta signaling cascade.
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Affiliation(s)
- Catherine A Kraft
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106-4970, USA
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Boswell SA, Ongusaha PP, Nghiem P, Lee SW. The protective role of a small GTPase RhoE against UVB-induced DNA damage in keratinocytes. J Biol Chem 2006; 282:4850-4858. [PMID: 17170105 DOI: 10.1074/jbc.m610532200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RhoE, a p53 target gene, was identified as a critical factor for the survival of human keratinocytes in response to UVB. The Rho family of GTPases regulates many aspects of cellular behavior through alterations to the actin cytoskeleton, acting as molecular switches cycling between the active, GTP-bound and the inactive, GDP-bound conformations. Unlike typical Rho family proteins, RhoE (also known as Rnd3) is GTPase-deficient and thus expected to be constitutively active. In this study, we investigated the response of cultured human keratinocyte cells to UVB irradiation. RhoE protein levels increase upon exposure to UVB, and ablation of RhoE induction through small interfering RNA resulted in a significant increase in apoptosis and a reduction in the levels of the pro-survival targets p21, Cox-2, and cyclin D1, as well as an increase of reactive oxygen species levels when compared with control cells. These data indicate that RhoE is a pro-survival factor acting upstream of p38, JNK, p21, and cyclin D1. HaCat cells expressing small interfering RNA to p53 indicate that RhoE functions independently of its known associates, p53 and Rho-associated kinase I (ROCK I). Targeted expression of RhoE in epidermis using skin-specific transgenic mouse model resulted in a significant reduction in the number of apoptotic cells following UVB irradiation. Thus, RhoE induction counteracts UVB-induced apoptosis and may serve as a novel target for the prevention of UVB-induced photodamage regardless of p53 status.
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Affiliation(s)
- Sarah A Boswell
- Dermatology Division, University of Washington, Seattle, Washington 98109
| | - Pat P Ongusaha
- Cutaneous Biology Research Center (CBRC), Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129 and the
| | - Paul Nghiem
- Dermatology Division, University of Washington, Seattle, Washington 98109
| | - Sam W Lee
- Cutaneous Biology Research Center (CBRC), Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129 and the.
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Qin JZ, Xin H, Sitailo LA, Denning MF, Nickoloff BJ. Enhanced Killing of Melanoma Cells by Simultaneously Targeting Mcl-1 and NOXA. Cancer Res 2006; 66:9636-45. [PMID: 17018621 DOI: 10.1158/0008-5472.can-06-0747] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
By deciphering the dysregulation of apoptosis in melanoma cells, new treatment approaches exploiting aberrant control mechanisms regulating cell death can be envisioned. Among the Bcl-2 family, a BH3-only member, NOXA, functions in a specific mitochondrial-based cell death pathway when melanoma cells are exposed to a proteasome inhibitor (e.g., bortezomib). Some therapeutic agents, such as bortezomib, not only induce proapoptotic Bcl-2 family members and active conformational changes in Bak and Bax but also are associated with undesirable effects, including accumulation of antiapoptotic proteins, such as Mcl-1. To enhance the bortezomib-mediated killing of melanoma cells, the apoptotic pathway involving NOXA was further investigated, leading to identification of an important target (i.e., the labile Bcl-2 homologue Mcl-1 but not other survival proteins). To reduce Mcl-1 levels, melanoma cells were pretreated with several different agents, including Mcl-1 small interfering RNA (siRNA), UV light, or the purine nucleoside analogue fludarabine. By simultaneously triggering production of NOXA (using bortezomib) as well as reducing Mcl-1 levels (using siRNA, UV light, or fludarabine), significantly enhanced killing of melanoma cells was achieved. These results show binding interactions between distinct Bcl-2 family members, such as NOXA and Mcl-1, in melanoma cells, paving the way for novel and rational therapeutic combination strategies, which target guardians of the proapoptotic Bak- and Bax-mediated pathways, against this highly aggressive and often fatal malignancy.
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Affiliation(s)
- Jian-Zhong Qin
- Department of Pathology, Loyola University Medical Center, Maywood, IL 60153, USA
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Abstract
BACKGROUND Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism. OBJECTIVE This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation. METHODS A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation. RESULTS It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation. CONCLUSION Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.
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Affiliation(s)
- Jeffrey Chow
- Department of Laboratory Medicine and Pathology, 4B1.19 Walter C Mackenzie Health Science Centre, University of Alberta, Edmonton, AB, Canada
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Abstract
Keratinocyte (KC) apoptosis plays a critical role in regulating epidermal development and restraining carcinogenesis. Apoptosis balances proliferation to maintain epidermal thickness, contributes to stratum corneum formation and may eliminate pre-malignant cells. Apart from the normal developmental program, KC apoptosis can be triggered by UV light and other stimuli. Dysfunctional apoptosis occurs in some skin diseases, such as psoriasis and skin cancer. Here we review the current state of knowledge of KC apoptosis, with particular focus on apoptotic signaling pathways and molecular mechanisms of apoptosis control, and discuss new insights into the complex role of apoptosis in skin carcinogenesis that are emerging from mouse models.
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Affiliation(s)
- Deepak Raj
- Huntsman Cancer Institute, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
- Department of Oncological Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
| | - Douglas E. Brash
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas Grossman
- Huntsman Cancer Institute, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
- Department of Oncological Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
- Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
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Chaturvedi V, Sitailo LA, Bodner B, Denning MF, Nickoloff BJ. Defining the caspase-containing apoptotic machinery contributing to cornification in human epidermal equivalents. Exp Dermatol 2006; 15:14-22. [PMID: 16364027 DOI: 10.1111/j.0906-6705.2005.00383.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Whether terminal differentiation/stratum corneum formation of keratinocytes (KCs) represents a form of programmed cell death, utilizing mediators of classical apoptosis, is unclear. Apoptosis, an evolutionarily conserved death process, is comprised of extrinsic and intrinsic pathways, which converge using caspase 3. To define upstream and downstream caspases involved in terminal differentiation, we utilized human epidermal equivalents (EEs). Using submerged cultures comprised of human KCs, EEs were sequentially analyzed before and after being raised to an air/liquid (A/L) interface at 3-24 h intervals. At each time point, EEs were analyzed morphologically and for specific enzyme activity to distinguish different initiator (caspases 1, 2, 8, 9) and effector caspases (3, 6, 7). Terminal differentiation began at 6-8 h, as defined by stratum corneum with loricirin expression and completed at 18-24 h producing an epidermis resembling normal skin. Enzyme activity for caspases 1, 2, 3, 6, 7, 8, and 9 (but not 4, 5) was enhanced (>two-fold nmol/mg/h) at 3-6 h compared with submerged cultures. Processing of caspase 14 occurred at 18 h, and cleaved caspase 14 was increased at 24 h. Activated caspase 3-positive and terminal deoxynucleotidyl transferase-mediated nick end labeling-positive KCs were identified in EEs at 3-6 h corresponding to initiation sites of terminal differentiation. Addition of caspase inhibitors reduced levels of involucrin and loricrin in EEs raised to an A/L interface. We conclude caspases function as important death effectors strategically positioned at intersection of intrinsic and extrinsic pathways in KCs undergoing stratum corneum formation.
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Chaturvedi V, Bodner B, Qin JZ, Nickoloff BJ. Knock down of p53 levels in human keratinocytes increases susceptibility to type I and type II interferon-induced apoptosis mediated by a TRAIL dependent pathway. J Dermatol Sci 2006; 41:31-41. [PMID: 16289694 DOI: 10.1016/j.jdermsci.2005.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 09/27/2005] [Accepted: 10/05/2005] [Indexed: 11/30/2022]
Abstract
BACKGROUND Keratinocytes (KCs) in healthy skin only undergo death following differentiation to produce stratum corneum. By contrast, in inflammatory pathological conditions featuring type I (IFN-alpha) and type II (IFN-gamma) interferons KCs undergo premature apoptosis. OBJECTIVE To define apoptotic susceptibility of KCs, response to interferons was examined. Since molecular cross-talk occurs between interferons and p53, potential mechanistic roles for p53 in KC apoptosis were investigated. METHODS Knock down of p53 was performed, and apoptotic response to addition of interferons was assessed using FACS and by staining for activated caspase 3 and TUNEL. Elucidation of death pathway was accomplished by using a dominant negative death receptor construct and a neutralizing TRAIL antibody. RESULTS Reduction in p53 levels in KCs by siRNA treatment enhanced, rather than reduced, apoptotic responses to IFN-alpha plus IFN-gamma. In an immortalized human KC cell line (HaCaT cells with both p53 alleles mutated) enhanced apoptotic susceptibility to interferon exposure was also observed. The mechanism for this enhanced apoptosis involved induction of TRAIL and its interaction with death receptors, as blocking the death receptor pathway using dominant negative FADD, or by addition of neutralizing antibody against TRAIL, reduced the apoptotic response to IFN-alpha and IFN-gamma. CONCLUSION These results indicate IFN-alpha plus IFN-gamma triggers apoptosis independent of p53 in HaCaT cells, and also demonstrate an unexpected survival role for p53 in human KCs as regards apoptotic responsiveness to cytokines such as IFN-alpha and IFN-gamma involving activation of TRAIL-related death receptors. Strategies enhancing p53 regulated survival proteins in KCs may be of therapeutic benefit in skin disorders characterized by activated immunocytes triggering premature KC apoptosis.
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