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Dong Y, Miao R, Feng R, Wang T, Yan J, Zhao X, Han X, Gan Y, Lin J, Li Y, Gan B, Zhao J. Edible and medicinal fungi breeding techniques, a review: Current status and future prospects. Curr Res Food Sci 2022; 5:2070-2080. [DOI: 10.1016/j.crfs.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 11/06/2022] Open
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Alotaibi A, Baumgartner A, Najafzadeh M, Cemeli E, Anderson D. <i>In Vitro</i> Investigation of DNA Damage Induced by the DNA Cross-Linking Agents Oxaliplatin and Satraplatin in Lymphocytes of Colorectal Cancer Patients. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/jct.2012.31011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Mason RS, Sequeira VB, Dixon KM, Gordon-Thomson C, Pobre K, Dilley A, Mizwicki MT, Norman AW, Feldman D, Halliday GM, Reeve VE. Photoprotection by 1alpha,25-dihydroxyvitamin D and analogs: further studies on mechanisms and implications for UV-damage. J Steroid Biochem Mol Biol 2010; 121:164-8. [PMID: 20399269 DOI: 10.1016/j.jsbmb.2010.03.082] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 02/28/2010] [Accepted: 03/26/2010] [Indexed: 10/19/2022]
Abstract
Ultraviolet (UV) irradiation causes DNA damage in skin cells, immunosuppression and photocarcinogenesis. 1alpha,25-dihydroxyvitamin D3 (1,25D) reduces UV-induced DNA damage in the form of cyclobutane pyrimidine dimers (CPD) in human keratinocytes in culture and in mouse and human skin. UV-induced immunosuppression is also reduced in mice by 1,25D, in part due to the reduction in CPD and a reduction in interleukin (IL-6. The cis-locked analog, 1alpha,25-dihydroxylumisterol3 (JN), which has almost no transactivating activity, reduces UV-induced DNA damage, apoptosis and immunosuppression with similar potency to 1,25D, consistent with a non-genomic signalling mechanism. The mechanism of the reduction in DNA damage in the form of CPD is unclear. 1,25D doubles nuclear expression of p53 compared to UV alone, which suggests that 1,25D facilitates DNA repair. Yet expression of a key DNA repair gene, XPG is not affected by 1,25D. Chemical production of CPD has been described. Incubation of keratinocytes with a nitric oxide donor, SNP, induces CPD in the dark. We previously reported that 1,25D reduced UV-induced nitrite in keratinocytes, similar to aminoguanidine, an inhibitor of nitric oxide synthase. A reduction in reactive nitrogen species has been shown to facilitate DNA repair, but in view of these findings may also reduce CPD formation via a novel mechanism.
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Affiliation(s)
- R S Mason
- Department of Physiology, Bosch Institute, Anderson Stuart Bldg F13, University of Sydney, NSW 2006, Australia.
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Genotoxic stress in plants: Shedding light on DNA damage, repair and DNA repair helicases. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2009; 681:134-149. [DOI: 10.1016/j.mrrev.2008.06.004] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 06/24/2008] [Accepted: 06/24/2008] [Indexed: 01/03/2023]
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Staszewski O, Nikolova T, Kaina B. Kinetics of gamma-H2AX focus formation upon treatment of cells with UV light and alkylating agents. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:734-740. [PMID: 18800352 DOI: 10.1002/em.20430] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Histone H2AX is rapidly phosphorylated in response to DNA double-strand breaks (DSBs) induced by ionizing radiation (IR). Here we show that DNA damage induced by alkylating agents [methyl methanesulfonate (MMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)] and ultraviolet light (UV-C) leads to a dose and time dependent accumulation of phosphorylated H2AX (gamma-H2AX). Time course experiments revealed that the number of gamma-H2AX foci reached peak levels 8 hr after MMS or MNNG treatment and declined to almost control values within 24 hr after exposure. Upon UV-C treatment, a biphasic response was observed with a maximum 12 hr after treatment. In 43-3B cells deficient in nucleotide excision repair (NER) the number of gamma-H2AX foci increased steadily. gamma-H2AX foci were preferentially formed in BrdU labeled cells. In proliferation compromised cells, the gamma-H2AX level was significantly reduced, indicating that most of the gamma-H2AX foci induced by UV-C and alkylating agent treatments were replication dependent. The data are in line with the view that DNA damage induced by UV-C light and simple alkylating agents, leads to the formation of DSBs during DNA replication giving rise to H2AX phosphorylation. In replicating NER defective cells, DSBs accumulate due to nonrepaired primary DNA lesions that produce a high level of DSBs during replication. The data support that gamma-H2AX foci are a useful marker of DSBs that are induced by S-phase dependent genotoxins during replication.
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Affiliation(s)
- Ori Staszewski
- Department of Toxicology, University of Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany
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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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Metry KJ, Zhao S, Neale JR, Doll MA, States JC, McGregor WG, Pierce WM, Hein DW. 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine-induced DNA adducts and genotoxicity in chinese hamster ovary (CHO) cells expressing human CYP1A2 and rapid or slow acetylator N-acetyltransferase 2. Mol Carcinog 2007; 46:553-63. [PMID: 17295238 DOI: 10.1002/mc.20302] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Heterocyclic amine carcinogens such as 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) are present in diet and cigarette smoke. Bioactivation in humans includes N-hydroxylation catalyzed by cytochrome P4501A2 possibly followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). Nucleotide excision repair-deficient Chinese hamster ovary (CHO) cells were stably transfected with human CYP1A2 and either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. CYP1A2 and NAT2 catalytic activities were undetectable in untransfected CHO cell lines. CYP1A2 catalytic activity levels did not differ significantly (P > 0.05) among the CYP1A2-transfected cell lines. Cells transfected with NAT2*4 had significantly higher levels of N-acetyltransferase (P = 0.0001) and N-hydroxy-PhIP O-acetyltransferase (P = 0.0170) catalytic activity than cells transfected with NAT2*5B. PhIP caused dose-dependent decreases in cell survival and significant (P < 0.001) increases in mutagenesis measured at the hypoxanthine phosphoribosyl transferase (hprt) locus in all the CYP1A2-transfected cell lines. Transfection with NAT2*4 or NAT2*5B did not further increase hprt mutagenesis. PhIP-induced hprt mutant cDNAs were sequenced, and 80% of the mutations were single base substitutions at G:C base pairs. dG-C8-PhIP DNA adduct levels were dose-dependent in the order: untransfected < transfected with CYP1A2 < transfected with CYP1A2 and NAT2*5B < transfected with CYP1A2 and NAT2*4. Following incubation with 1.2 microM PhIP, DNA adduct levels were significantly (P < 0.05) higher in CHO cells transfected with CYP1A2/NAT2*4 versus CYP1A2/NAT2*5B. These results strongly support an activation role for CYP1A2 in PhIP-induced mutagenesis and DNA damage and suggest a modest effect of human NAT2 and its genetic polymorphism on PhIP DNA adduct levels.
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Affiliation(s)
- Kristin J Metry
- Department of Pharmacology and Toxicology and James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY 40292, USA
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Belleudi F, Leone L, Aimati L, Stirparo MG, Cardinali G, Marchese C, Frati L, Picardo M, Torrisi MR. Endocytic pathways and biological effects induced by UVB‐dependent or ligand‐dependent activation of the keratinocyte growth factor receptor. FASEB J 2005; 20:395-7. [PMID: 16354720 DOI: 10.1096/fj.05-3934fje] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
UVB exposure of epidermal cells is known to trigger early and late molecular pathways dependent on receptor tyrosine kinases and reactive oxygen species (ROS). We have recently reported that UVB irradiation induces tyrosine phosphorylation, kinase activation, and internalization of the receptor for the keratinocyte growth factor (KGFR), a paracrine mediator of epithelial growth, differentiation, and survival. Here we analyzed in more detail the UVB-induced endocytic pathway of KGFR and the role of KGFR activation and internalization in regulating UVB-promoted apoptosis and cell cycle arrest. Immunogold electron microscopy and confocal analysis revealed that the UVB-induced endocytosis of KGFR occurs through clathrin-coated pits and that the internalized receptors are sorted to the degradative route and reach the lysosomal compartment with a timing similar to that induced by their ligand KGF. Treatment with the anti-oxidant N-acetylcysteine inhibited KGFR endocytosis, suggesting that the receptor internalization is mediated by the intracellular production of ROS. The ligand-independent KGFR endocytic pathway induced by UVB requires receptor kinase activity and tyrosine phosphorylation and involves transient receptor ubiquitination. Inhibition of KGFR activity reduces both the KGF-mediated proliferative response and the UVB-promoted apoptotic cell death, indicating a different effect of ligand-induced and UVB-induced KGFR triggering. In addition, receptor internalization leads to protection from apoptosis caused by UVB exposure. Finally, we compared directly the behavior of KGFR with that of the epidermal growth factor receptor (EGFR) upon UVB exposure. Surprisingly, biochemical and immunofluorescence analysis showed that EGFR, differently from KGFR, does not undergo UVB-induced tyrosine phosphorylation and internalization. Taken together, our results suggest a differential role of KGFR and EGFR in the response of epidermal cells to UVB possibly because KGFR endocytosis could be crucial for attenuation of survival signals in the suprabasal layers of human skin.
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Affiliation(s)
- Francesca Belleudi
- Dipartimento di Medicina Sperimentale e Patologia, Università di Roma La Sapienza, Rome, Italy
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Darzynkiewicz Z, Huang X, Okafuji M. Cytometric assessment of DNA damage in relation to cell cycle phase and apoptosis. Cell Prolif 2005; 314:81-93. [PMID: 16673876 PMCID: PMC1458375 DOI: 10.1385/1-59259-973-7:081] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Reviewed are the methods aimed to detect DNA damage in individual cells, estimate its extent and relate it to cell cycle phase and induction of apoptosis. They include the assays that reveal DNA fragmentation during apoptosis, as well as DNA damage induced by genotoxic agents. DNA fragmentation that occurs in the course of apoptosis is detected by selective extraction of degraded DNA. DNA in chromatin of apoptotic cells shows also increased propensity to undergo denaturation. The most common assay of DNA fragmentation relies on labelling DNA strand breaks with fluorochrome-tagged deoxynucleotides. The induction of double-strand DNA breaks (DSBs) by genotoxic agents provides a signal for histone H2AX phosphorylation on Ser139; the phosphorylated H2AX is named gammaH2AX. Also, ATM-kinase is activated through its autophosphorylation on Ser1981. Immunocytochemical detection of gammaH2AX and/or ATM-Ser1981(P) are sensitive probes to reveal induction of DSBs. When used concurrently with analysis of cellular DNA content and caspase-3 activation, they allow one to correlate the extent of DNA damage with the cell cycle phase and with activation of the apoptotic pathway. The presented data reveal cell cycle phase-specific patterns of H2AX phosphorylation and ATM autophosphorylation in response to induction of DSBs by ionizing radiation, topoisomerase I and II inhibitors and carcinogens. Detection of DNA damage in tumour cells during radio- or chemotherapy may provide an early marker predictive of response to treatment.
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Huang X, Halicka HD, Traganos F, Tanaka T, Kurose A, Darzynkiewicz Z. Cytometric assessment of DNA damage in relation to cell cycle phase and apoptosis. Cell Prolif 2005; 38:223-43. [PMID: 16098182 PMCID: PMC1360473 DOI: 10.1111/j.1365-2184.2005.00344.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Reviewed are the methods aimed to detect DNA damage in individual cells, estimate its extent and relate it to cell cycle phase and induction of apoptosis. They include the assays that reveal DNA fragmentation during apoptosis, as well as DNA damage induced by genotoxic agents. DNA fragmentation that occurs in the course of apoptosis is detected by selective extraction of degraded DNA. DNA in chromatin of apoptotic cells shows also increased propensity to undergo denaturation. The most common assay of DNA fragmentation relies on labelling DNA strand breaks with fluorochrome-tagged deoxynucleotides. The induction of double-strand DNA breaks (DSBs) by genotoxic agents provides a signal for histone H2AX phosphorylation on Ser139; the phosphorylated H2AX is named gammaH2AX. Also, ATM-kinase is activated through its autophosphorylation on Ser1981. Immunocytochemical detection of gammaH2AX and/or ATM-Ser1981(P) are sensitive probes to reveal induction of DSBs. When used concurrently with analysis of cellular DNA content and caspase-3 activation, they allow one to correlate the extent of DNA damage with the cell cycle phase and with activation of the apoptotic pathway. The presented data reveal cell cycle phase-specific patterns of H2AX phosphorylation and ATM autophosphorylation in response to induction of DSBs by ionizing radiation, topoisomerase I and II inhibitors and carcinogens. Detection of DNA damage in tumour cells during radio- or chemotherapy may provide an early marker predictive of response to treatment.
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Affiliation(s)
- Xuan Huang
- Brander Cancer Research Institute, New York Medical College, Valhalla, NY 10532, USA
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Sakai Y, Khajoee V, Ogawa Y, Kusuhara K, Katayama Y, Hara T. A novel transfection method for mammalian cells using gas plasma. J Biotechnol 2005; 121:299-308. [PMID: 16216376 DOI: 10.1016/j.jbiotec.2005.08.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 08/02/2005] [Accepted: 08/19/2005] [Indexed: 01/21/2023]
Abstract
Introduction of foreign genes into target cells is a crucial step for achievement of gene therapy. We have recently developed a novel transfection system for eukaryotic cells, namely the electric pulse-activated gas plasma generator. To measure the transfection efficiency and mortality by flow-cytometry, we employed enhanced green fluorescent protein and propidium iodide staining, respectively. One day after the 1-3s plasma exposures with DNA concentration at 0.5 microg/microl, favorable transfection efficiencies (17.8-21.6%) and mortalities (0.65-2.86%) were obtained for HeLa-S3, HT-1080 and MCF-7 cells. The recipient cells became transiently permeable for plasmid DNA during the plasma exposure, suggesting that plasma-mediated transfection may involve similar mechanisms that accounts for electroporation. The relatively low mortality rates are encouraging in our attempt to apply this system to the various cell lines including the primary cell cultures.
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Affiliation(s)
- Yasunari Sakai
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
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Decome L, De Méo M, Geffard A, Doucet O, Duménil G, Botta A. Evaluation of photolyase (Photosome) repair activity in human keratinocytes after a single dose of ultraviolet B irradiation using the comet assay. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 79:101-8. [PMID: 15878115 DOI: 10.1016/j.jphotobiol.2004.11.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 11/13/2004] [Accepted: 11/30/2004] [Indexed: 10/25/2022]
Abstract
Photosome is constituted of photolyases included in liposomes. Photolyase is a bacterial enzyme that can repair ultraviolet B (UVB)-induced cyclobutane pyrimidine dimers (CPD) in eukaryotic cells. A modified version of the alkaline comet assay has been set up to evaluate the repair activity of this enzyme after a single dose of UVB (312 nm, 0.06 J/cm2) in human keratinocytes. The formation of single strand breaks (SSB) induced by the UVA photoactivation of the enzyme (1.2 J/cm2) was inhibited by the pretreatment of the cells with 4 mM L-ergothioneine (ERT) during 30 min at 37 degrees C. To increase the sensitivity of the comet assay, an additional lysis was used with a buffer containing sodium dodecyl sulfate (0.5%) and proteinase K (0.1 mg/ml) for 60 min at 37 degrees C. Unrepaired CPD by photolyase were revealed by a second enzymatic treatment with T4 endonuclease V, a CPD specific glycosylase. UVB irradiation increased the SSB level in keratinocytes and additional T4NV treatment enhanced this SSB level by 1.5-2.0-fold confirming that CPD were the major base modifications generated by UVB irradiation. UVA-photoactivated Photosome repaired CPD lesions and decreased the SSB levels by 2.6-3.3-fold. Photosome could be an additional component of sunscreens to reduce the development of skin cancer.
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Affiliation(s)
- Laetitia Decome
- Laboratoire de Biogénotoxicologie et Mutagenèse Environnementale (EA 1784), Facultés de Pharmacie et de Médecine, Université de la Méditerranée, 27 Bd jean Moulin, Marseille Cedex 5, France
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Badgwell DB, Walker CM, Baker WT, Strickland FM. Ethanol and aloe emodin alter the p53 mutational spectrum in ultraviolet radiation-induced murine skin tumors. Mol Carcinog 2004; 39:127-38. [PMID: 14991742 DOI: 10.1002/mc.10170] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mutations in the p53 tumor-suppressor gene contribute to the development of skin cancer, and the spectrum of mutations in this gene correlates with specific physical and chemical carcinogens in the environment. Cosmetics may contain alcohols and/or aloe emodin (AE). Although these compounds are not carcinogenic when applied to the skin, they may increase the carcinogenicity of ultraviolet (UV) radiation. We investigated whether ethanol (EtOH) and AE alone or combined with UV radiation cause mutations in the p53 gene. In the absence of UV radiation, C3H/HeN mice chronically treated for up to 33 wk with AE in 25% EtOH-in-water vehicle or vehicle alone failed to develop tumors and had no mutations in exons 4-8 of the p53 gene. UV radiation alone induced skin tumors, which had mutations predominantly in p53 exons 5 and 8. In contrast, mutations arising in UV + EtOH-or UV + AE-treated groups were more broadly distributed throughout the p53 gene. Mutations were found in exons 4, 6, and 7, as well as in exons 5 and 8. This altered distribution of mutations across the p53 DNA sequence more closely resembles the pattern observed in TP53 from human skin tumors at sun-exposed sites than that in the p53 gene of mice treated with UV alone. Thus, treatment with UV radiation in combination with two chemicals not thought to be carcinogenic, alcohol, and AE results in a broader distribution of mutations in a critical tumor-suppressor gene.
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Affiliation(s)
- Donna B Badgwell
- Department of Immunology, The University of Texas M D Anderson Cancer Center, Houston, Texas, USA
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Liu Z, Hong SW, Escobar M, Vierling E, Mitchell DL, Mount DW, Hall JD. Arabidopsis UVH6, a homolog of human XPD and yeast RAD3 DNA repair genes, functions in DNA repair and is essential for plant growth. PLANT PHYSIOLOGY 2003; 132:1405-14. [PMID: 12857822 PMCID: PMC167080 DOI: 10.1104/pp.103.021808] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2003] [Revised: 03/30/2003] [Accepted: 04/17/2003] [Indexed: 05/18/2023]
Abstract
To evaluate the genetic control of stress responses in Arabidopsis, we have analyzed a mutant (uvh6-1) that exhibits increased sensitivity to UV light, a yellow-green leaf coloration, and mild growth defects. We have mapped the uvh6-1 locus to chromosome I and have identified a candidate gene, AtXPD, within the corresponding region. This gene shows sequence similarity to the human (Homo sapiens) XPD and yeast (Saccharomyces cerevisiae) RAD3 genes required for nucleotide excision repair. We propose that UVH6 is equivalent to AtXPD because uvh6-1 mutants carry a mutation in a conserved residue of AtXPD and because transformation of uvh6-1 mutants with wild-type AtXPD DNA suppresses both UV sensitivity and other defective phenotypes. Furthermore, the UVH6/AtXPD protein appears to play a role in repair of UV photoproducts because the uvh6-1 mutant exhibits a moderate defect in the excision of UV photoproducts. This defect is also suppressed by transformation with UVH6/AtXPD DNA. We have further identified a T-DNA insertion in the UVH6/AtXPD gene (uvh6-2). Plants carrying homozygous insertions were not detected in analyses of progeny from plants heterozygous for the insertion. Thus, homozygous insertions appear to be lethal. We conclude that the UVH6/AtXPD gene is required for UV resistance and is an essential gene in Arabidopsis.
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Affiliation(s)
- Zongrang Liu
- Departments of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA
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Marchese C, Maresca V, Cardinali G, Belleudi F, Ceccarelli S, Bellocci M, Frati L, Torrisi MR, Picardo M. UVB-induced activation and internalization of keratinocyte growth factor receptor. Oncogene 2003; 22:2422-31. [PMID: 12717419 DOI: 10.1038/sj.onc.1206301] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ultraviolet irradiation of mammalian cells induces several events that include activation of growth factor receptors and triggering of signal transduction pathway. Most of the UV responses are mediated by the production of reactive oxygen species (ROS) and can be blocked by antioxidants. In this study, we analysed the effect of UVB irradiation at physiologic doses and that of the pro-oxidant agent cumene hydroperoxide (CUH) on the activation of the receptor for keratinocyte growth factor (KGF), a key mediator of epithelial growth and differentiation. Exposure to both UVB (30-150 mJ/cm(2)) and CUH (200 microM of NIH3T3 KGFR (KGF receptors) transfectants caused a rapid tyrosine phosphorylation and activation of KGFR similar to that induced by KGF, and internalization of the activated receptor. The KGFR expression appeared unmodified by the treatments. Ultrastructural observations of both UVB- and CUH-treated cells showed a normal morphology of the plasma membranes and intracellular organelles. The antioxidant N-acetylcysteine inhibited UVB-induced receptor phosphorylation. The generation of an intracellular oxidative stress was detected as a decrease of catalase activity and of vitamin E, and reduced glutathione levels, whereas superoxide dismutase activity was not significantly modified. A peroxidation of polyunsaturated fatty acids of cell membranes was observed after both treatments, associated with the intracellular oxidative stress. Similar biochemical events were observed on NIH3T3 untransfected control cells, suggesting that KGFR activation follows intracellular generation of ROS and is not associated with a scavenging effect. Taken together our results demonstrate that exposure to UVB and to oxidant stimuli induces a rapid intracellular production of ROS, which in turn are capable of triggering KGFR activation and internalization, similar to those induced by KGF.
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Affiliation(s)
- Cinzia Marchese
- Dipartimento di Medicina Sperimentale e Patologia, Università di Roma La Sapienza, viale Regina Elena 324, Rome 00161, Italy.
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McCollum AT, Nasr P, Estus S. Calpain activates caspase-3 during UV-induced neuronal death but only calpain is necessary for death. J Neurochem 2002; 82:1208-20. [PMID: 12358768 DOI: 10.1046/j.1471-4159.2002.01057.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
While caspases have been strongly implicated in delayed neuronal death in a variety of experimental paradigms, other proteases such as calpain can also contribute to neuronal death. To evaluate the relative roles of caspase and calpain, we used a model system wherein UV treatment induced moderate or severe delayed cortical neuronal death, as quantified by propidium iodide and calcein AM. UV treatment led to increases in both caspase and calpain activation. Calpain inhibitor III (MDL-28170) reduced caspase activation, suggesting that caspase activation was mediated by calpain. Calpain contributed to neuronal death, as indicated by strong neuroprotection provided by calpain inhibitor III, calpeptin, or Ca2+-free medium. In contrast, caspase inhibitors were not neuroprotective. These results suggest that UV neurotoxicity is mediated by a loss of Ca2+ homeostasis which leads to a calpain-dependent, caspase-independent cell death. That calpain, but not caspase, may mediate death in instances involving the activation of both proteases may have relevance to other neuronal death models.
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Affiliation(s)
- Adrian T McCollum
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, USA
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Takata KI, Ishikawa G, Hirose F, Sakaguchi K. Drosophila damage-specific DNA-binding protein 1 (D-DDB1) is controlled by the DRE/DREF system. Nucleic Acids Res 2002; 30:3795-808. [PMID: 12202765 PMCID: PMC137413 DOI: 10.1093/nar/gkf490] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We succeeded in cloning the gene, termed d-ddb1, for a Drosophila homolog of the p127 subunit of the human damage-specific DNA-binding protein, thought to recognize (6-4) photoproducts and related structures. In Drosophila, the gene product (D-DDB1) also appeared to play a role as a repair factor, d-ddb1 knockout Kc cells generated with a RNAi method being sensitive to UV. In addition, UV or methyl methanesulfonate treatment increased d-ddb1 transcripts. However, we found that the gene is controlled by the DRE/DREF system, which is generally responsible for activating the promoters of proliferation-related genes. Moreover, during Drosophila development, the transcription of d-ddb1 changed greatly, with the highest levels in unfertilized eggs, indicating that external injury to DNA is not essential to D-DDB1 function. Interestingly, as with UV irradiation-induced transfer of D-DDB1 to the nucleus from the cytoplasm, during spermatogenesis the protein transiently shifted from one cell compartment to the other. The results indicate that D-DDB1 not only contributes to the DNA repair system, but also has a role in cell proliferation and development.
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Affiliation(s)
- Kei-ichi Takata
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda-shi, Chiba-ken 278-8510, Japan
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18
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Abstract
Oxaliplatin is a third generation platinum compound that differs from cisplatin and carboplatin in having a broader spectrum of antitumour activity. Molecular studies suggest that oxaliplatin adducts are recognised and processed differently than those produced by the earlier generation Pt-containing drugs. We report here studies on the kinetics of the development of oxaliplatin resistance, and the changes in the cellular pharmacology of oxaliplatin that accompany the emergence of the resistant phenotype in five parental human tumour cell lines and their sub-lines selected for acquired oxaliplatin resistance in vitro. During selection, resistance did not substantially increase until after at least six cycles of oxaliplatin treatment. Oxaliplatin demonstrated schedule-dependency with a 1-h exposure being substantially less cytotoxic than a continuous exposure. Whole cell uptake was linear with concentration, but uptake in the resistant cells averaged only 27+/-10 S.D.% of that in the sensitive cells. Pt accumulation in DNA was markedly reduced in four of the five resistant cell lines, but this did not correlate with either IC(50) or total cellular accumulation. Four of the five resistant sub-lines also demonstrated increased tolerance to adducts in DNA that ranged from 3.1 to 7.6-fold. We conclude that development of acquired resistance to oxaliplatin is accompanied by independent defects in both whole cell uptake and in adduct formation.
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Affiliation(s)
- M Mishima
- Department of Obstetrics and Gynecology, University of Tokyo, Japan
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19
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O-Wang J, Kajiwara K, Kawamura K, Kimura M, Miyagishima H, Koseki H, Tagawa M. An essential role for REV3 in mammalian cell survival: absence of REV3 induces p53-independent embryonic death. Biochem Biophys Res Commun 2002; 293:1132-7. [PMID: 12051777 DOI: 10.1016/s0006-291x(02)00341-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The REV3 gene of budding yeast encodes the catalytic subunit of DNA polymerase zeta that carries out translesion DNA synthesis. While REV3-null yeast mutants are viable and exhibit normal growth, Rev3-deficient mice die around midgestation of embryogenesis, which is accompanied by massive apoptosis of cells within the embryo proper. We have investigated whether REV3 is required for the survival of mouse cells and whether the embryonic lethality caused by REV3 deficiency can be rescued by introduction of a Rev3 transgene or by inactivation of p53, the cellular gatekeeper that regulates DNA damage-induced apoptosis. We show that Rev3(-/-) blastocysts were unable to survive and grow in culture but expression of a Rev3 transgene restored their outgrowth. Moreover, Rev3 transgene expression suppressed the apoptosis in E7.5 Rev3(-/-) embryos. The Rev3(-/-) embryonic lethality, however, was not rescued by either Rev3 transgene expression or p53 deficiency. These results reveal an essential role for REV3 in the survival and growth of mammalian cells and suggest that Rev3(-/-) embryonic death occurs in a p53-independent pathway.
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Affiliation(s)
- Jiyang O-Wang
- Division of Pathology, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuo-ku, Chiba 260-8717, Japan.
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20
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Kim AL, Athar M, Bickers DR, Gautier J. Ultraviolet-B-induced G1 arrest is mediated by downregulation of cyclin-dependent kinase 4 in transformed keratinocytes lacking functional p53. J Invest Dermatol 2002; 118:818-24. [PMID: 11982759 DOI: 10.1046/j.1523-1747.2002.01734.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In order to identify potential novel targets for ultraviolet-B-induced skin tumorigenesis, we assessed the effect of ultraviolet-B exposure on cell cycle progression of transformed keratinocytes with mutant p53. We show that ultraviolet-B exposure of human epidermoid carcinoma A431 cells results in G1 cell cycle arrest in both asynchronously growing and synchronized cells. A significant increase in G1 cell population was observed following exposure to doses of ultraviolet-B as low as 10 mJ per cm2. When irradiated with ultraviolet-B, cells synchronized in G1 with mimosine did not exit G1. G1 cell cycle arrest was associated with a decrease in the hyperphosphorylated forms of retinoblastoma protein that was detectable within 4 h and gradually disappeared by 12 h. We also observed a decrease in cyclins D1, D2, and D3, and cyclin-dependent kinase 4 proteins, and a concomitant decrease in cyclin-dependent kinase 4/cyclin D1 associated kinase activity, whereas ultraviolet-B exposure had no effect on cyclin-dependent kinase 2 and cyclin-dependent kinase 6 levels during this time period. Incubation of cells with proteasome inhibitors MG-115 and MG-132 prevented the decrease in cyclin D1, D2, and D3, and cyclin-dependent kinase 4 protein. Taken together, our results suggest that ultraviolet-B-induced cell cycle arrest in A431 cells is mediated by cyclin-dependent kinase 4 downregulation. This identifies a novel pathway for G1 cell cycle arrest in transformed keratinocytes following ultraviolet-B irradiation.
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Affiliation(s)
- Arianna L Kim
- Department of Dermatology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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21
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Dunkern TR, Kaina B. Cell proliferation and DNA breaks are involved in ultraviolet light-induced apoptosis in nucleotide excision repair-deficient Chinese hamster cells. Mol Biol Cell 2002; 13:348-61. [PMID: 11809844 PMCID: PMC65093 DOI: 10.1091/mbc.01-05-0225] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
UV light targets both membrane receptors and nuclear DNA, thus evoking signals triggering apoptosis. Although receptor-mediated apoptosis has been extensively investigated, the role of DNA damage in apoptosis is less clear. To analyze the importance of DNA damage induced by UV-C light in apoptosis, we compared nucleotide excision repair (NER)-deficient Chinese hamster ovary cells (lines 27-1 and 43-3B mutated for the repair genes ERCC3 and ERCC1, respectively) with the corresponding DNA repair-proficient fibroblasts (CHO-9 and ERCC1 complemented 43-3B cells). NER-deficient cells were hypersensitive as to the induction of apoptosis, indicating that apoptosis induced by UV-C light is due to unrepaired DNA base damage. Unrepaired lesions, however, do not activate the apoptotic pathway directly because apoptosis upon UV-C irradiation requires DNA replication and cell proliferation. It is also shown that in NER-deficient cells unrepaired lesions are converted into DNA double-strand breaks (DSBs) and chromosomal aberrations by a replication-dependent process that precedes apoptosis. We therefore propose that DSBs arising from replication of DNA containing nonrepaired lesions act as an ultimate trigger of UV-C-induced apoptosis. Induction of apoptosis by UV-C light was related to decline in the expression level of Bcl-2 and activation of caspases. Decline of Bcl-2 and subsequent apoptosis might also be caused, at least in part, by UV-C-induced blockage of transcription, which was more pronounced in NER-deficient than in wild-type cells. This is in line with experiments with actinomycin D, which provoked Bcl-2 decline and apoptosis. UV-C-induced apoptosis due to nonrepaired DNA lesions, replication-dependent formation of DSBs, and activation of the mitochondrial damage pathway is independent of functional p53 for which the cells are mutated.
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Affiliation(s)
- Torsten R Dunkern
- Institute of Toxicology, Division of Applied Toxicology, University of Mainz, D-55131 Mainz, Germany
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22
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Straface E, Giacomoni PU, Malorni W. Cultured cells as a model system for the study of UV-induced cytotoxicity. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 63:52-60. [PMID: 11684451 DOI: 10.1016/s1011-1344(01)00215-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In vivo, UV radiation induces a series of morphological and ultrastructural alterations in human epidermis. These and other changes eventually lead to well described pathological modifications including erythema and cancer. Morphological alterations are easier to detect in cultured cells, such as human keratinocytes or other epithelial cells. One can use different intensities of different radiation types (UV-A, -B and -C) and expose cell monolayers to different doses. In these experimental conditions it is possible to evaluate radiation risks and to provide additional information thanks to the reproducibility and the enormous amplification of the phenomena normally occurring in vivo. Alterations observed in structural studies can be summarized as the succession of the following events: (i) cell retraction with loss of cell-cell interactions; (ii) surface blebbing; and eventually (iii) cell death. Cytoskeletal components play a key role in this cascade. Morphogenesis of these changes can be ascribed to oxidative modifications due to reactive oxygen species formation following radiation that can modify both cell membrane and cytoskeleton. The use of in vitro systems can be of great relevance in the understanding of the pathogenetic mechanisms of UV radiation changes and to determine possible drugs capable of counteracting UV-mediated subcellular pathology.
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Affiliation(s)
- E Straface
- Department of Ultrastructures, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
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23
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Abstract
Chronic photodamage of the skin manifests itself as extrinsic skin ageing (photoageing) and photocarcinogenesis. DNA photodamage and UV-generated reactive oxygen species are the initial molecular events that lead to most of the typical histological and clinical manifestations of chronic photodamage of the skin. Knowledge of the UV-absorbing chromophores in the skin and of the molecular mechanisms leading to the unwanted effects of sun exposure provide a basis for the development of novel strategies for the prevention and repair of photoageing. This review provides an overview of the photochemistry of the major skin chromophores and their relationship to chronic photodamage.
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Affiliation(s)
- F Trautinger
- Department of Dermatology, Division of Special and Environmental Dermatology, University of Vienna, Vienna, Austria.
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24
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van den Wijngaard R, Wankowicz-Kalinska A, Pals S, Weening J, Das P. Autoimmune melanocyte destruction in vitiligo. J Transl Med 2001; 81:1061-7. [PMID: 11502857 DOI: 10.1038/labinvest.3780318] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- R van den Wijngaard
- Department of Pathology, Academic Medical Center, Amsterdam University, Amsterdam, The Netherlands
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25
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Matassa AA, Carpenter L, Biden TJ, Humphries MJ, Reyland ME. PKCδ Is Required for Mitochondrial-dependent Apoptosis in Salivary Epithelial Cells. J Biol Chem 2001; 276:29719-28. [PMID: 11369761 DOI: 10.1074/jbc.m100273200] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We report here that the novel protein kinase C isoform, PKCdelta, is required at or prior to the level of the mitochondria for apoptosis induced by a diverse group of cell toxins. We have used adenoviral expression of a kinase-dead (KD) mutant of PKCdelta to explore the requirement for PKCdelta in the mitochondrial-dependent apoptotic pathway. Expression of PKCdeltaKD, but not PKCalphaKD, in salivary epithelial cells resulted in a dose-dependent inhibition of apoptosis induced by etoposide, UV-irradiation, brefeldin A, and paclitaxel. DNA fragmentation was blocked up to 71% in parotid C5 cells infected with the PKCdeltaKD adenovirus, whereas caspase-3 activity was inhibited up to 65%. The activation of caspase-9-like proteases by all agents was also inhibited in parotid C5 cells expressing PKCdeltaKD. The ability of PKCdeltaKD to block the loss of mitochondrial membrane potential was similarly determined. Expression of PKCdeltaKD blocked the decrease in mitochondrial membrane potential observed in cells treated with etoposide, UV, brefeldin A, or paclitaxel in a dose-dependent manner. In contrast to the protective function of PKCdeltaKD, expression of PKCdeltaWT resulted in a potent induction of apoptosis, which could be inhibited by co-infection with PKCdeltaKD. These results suggest that PKCdelta is a common intermediate in mitochondrial-dependent apoptosis in salivary epithelial cells.
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Affiliation(s)
- A A Matassa
- Departments of Basic Science and Oral Research, School of Dentistry and Cell and Structural Biology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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26
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Abstract
DNA hybridization arrays simultaneously measure the expression level for thousands of genes. These measurements provide a "snapshot" of transcription levels within the cell. A major challenge in computational biology is to uncover, from such measurements, gene/protein interactions and key biological features of cellular systems. In this paper, we propose a new framework for discovering interactions between genes based on multiple expression measurements. This framework builds on the use of Bayesian networks for representing statistical dependencies. A Bayesian network is a graph-based model of joint multivariate probability distributions that captures properties of conditional independence between variables. Such models are attractive for their ability to describe complex stochastic processes and because they provide a clear methodology for learning from (noisy) observations. We start by showing how Bayesian networks can describe interactions between genes. We then describe a method for recovering gene interactions from microarray data using tools for learning Bayesian networks. Finally, we demonstrate this method on the S. cerevisiae cell-cycle measurements of Spellman et al. (1998).
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Affiliation(s)
- N Friedman
- School of Computer Science and Engineering, Hebrew University, Jerusalem, Israel.
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27
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Lin X, Ramamurthi K, Mishima M, Kondo A, Howell SB. p53 interacts with the DNA mismatch repair system to modulate the cytotoxicity and mutagenicity of hydrogen peroxide. Mol Pharmacol 2000; 58:1222-9. [PMID: 11093757 DOI: 10.1124/mol.58.6.1222] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study focused on the question of how the DNA mismatch repair (MMR) system and p53 interact to maintain genomic integrity in the presence of the mutagenic stress induced by hydrogen peroxide (H(2)O(2)). The cytotoxic and mutagenic effects of H(2)O(2) were compared in four colon carcinoma sublines: HCT116, HCT116/E6, HCT116+ch3, and HCT116+ch3/E6, representing MMR(-)/p53(+), MMR(-)/p53(-), MMR(+)/p53(+), and MMR(+)/p53(-) phenotypes, respectively. Loss of p53 in MMR-proficient cells did not significantly alter cellular sensitivity to H(2)O(2), but disruption of p53 in MMR-deficient cells resulted in substantial resistance to H(2)O(2) (IC(50) values of 203.8 and 66.2 microM for MMR(-)/p53(-) and MMR(-)/p53(+) cells, respectively). The effect of loss of p53 and MMR function on sensitivity to the mutagenic effect of H(2)O(2) paralleled the effects on cytotoxic sensitivity. In MMR-deficient cells, loss of p53 resulted in a 3.5- and 2.2-fold increase in the generation of 6-thiogunaine and ouabain-resistant clones, respectively. Loss of MMR in combination with loss of p53 synergistically increased the frequency of frameshift mutations in the CA repeat tracts of the out-of-frame shuttle vector pZCA29 and further promoted instability of microsatellite sequences under H(2)O(2) stress. Flow cytometric analysis showed that H(2)O(2) treatment produced a G(l) and G(2)/M phase arrest in MMR(+)/p53(+) cells. Loss of MMR did not alter the ability of H(2)O(2) to activate either checkpoint; loss of p53 in either the MMR-proficient or deficient cells resulted in impairment of the G(l) arrest and a more pronounced G(2)/M arrest. H(2)O(2) caused a greater and more longed increase in p53 protein levels in MMR-proficient than in the MMR-deficient cells. The results demonstrate that the effect of disabling p53 function is modulated by the proficiency of the MMR system (and vice versa) and that there is an overlap between the functions of p53 and the MMR system with respect to the activation of apoptosis and mutagenesis after an oxidative stress.
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Affiliation(s)
- X Lin
- Department of Medicine and the Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
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28
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Hong CY, Huang SC, Lin SK, Lee JJ, Chueh LL, Lee CH, Lin JH, Hsiao M. Norcantharidin-induced post-G(2)/M apoptosis is dependent on wild-type p53 gene. Biochem Biophys Res Commun 2000; 276:278-85. [PMID: 11006118 DOI: 10.1006/bbrc.2000.3341] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Norcantharidin (NCTD), a synthetic analogue of phosphatase type 2A inhibitors, cantharidin, was shown to have limited effects in treating human and animal tumors. The tumor cell killing mechanisms by norcantharidin, however, remain unclear. In this report, we wished to investigate the mechanisms of norcantharidin-mediated cytotoxicity. Effort was made to investigate whether norcantharidin exerted its cytotoxicity through a p53-dependent or -independent mechanism. RT-2 (wtp53) and U251 (mutant p53) glioblastoma cell lines were exposed to norcantharidin at different dosages. Time-course fluorescent-activated cell sorting (FACS) analysis showed that high doses of norcantharidin arrested the cells at the G(2)/M phase and subsequent post-G(2)/M apoptosis in RT-2 cell line. In comparison, the U251 cell line was found resistant to norcantharidin-induced cytotoxicity. Restoring wild-type p53 gene function in the U251 cell line after adenoviral infections induced tumor cell cytotoxicity after exposure to norcantharidin. These results showed that norcantharidin kills tumor cells efficiently corresponding to their endogenous p53 gene status. The results also showed the feasibility of using adenoviral p53 gene therapy to enhance chemosensitivity of tumor cells to norcantharidin.
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Affiliation(s)
- C Y Hong
- Department of Dentistry, National Taiwan University, Taipei, Taiwan, Republic of China
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29
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Flatt PM, Pietenpol JA. Mechanisms of cell-cycle checkpoints: at the crossroads of carcinogenesis and drug discovery. Drug Metab Rev 2000; 32:283-305. [PMID: 11139130 DOI: 10.1081/dmr-100102335] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Human tumors arise from multiple genetic changes that gradually transform growth-limited cells into highly invasive cells that are unresponsive to growth controls. The genetic evolution of normal cells into cancer cells is largely determined by the fidelity of DNA replication, repair, and division. Cell-cycle arrest in response to stress is integral to the maintenance of genomic integrity. The control mechanisms that restrain cell-cycle transition or induce apoptotic signaling pathways after cell stress are known as cell-cycle checkpoints. This review will focus on the mechanisms of cell-cycle checkpoint pathways and how different components of these pathways are frequently altered in the genesis of human tumors. As our knowledge of cell-cycle regulation and checkpoints increases, so will our understanding of how xenobiotic agents can affect these processes to either initiate or inhibit tumorigenesis.
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Affiliation(s)
- P M Flatt
- Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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