1
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Kelley MB, Geddes TJ, Ochiai M, Lampl NM, Kothmann WW, Fierstein SR, Kent V, DeCicco-Skinner K. Loss of Tpl2 activates compensatory signaling and resistance to EGFR/MET dual inhibition in v-RAS transduced keratinocytes. PLoS One 2022; 17:e0266017. [PMID: 35325006 PMCID: PMC8947257 DOI: 10.1371/journal.pone.0266017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/11/2022] [Indexed: 11/18/2022] Open
Abstract
Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer in the United States, affecting one million people per year. Patients with aggressive disease have limited treatment options and high mortality, highlighting the need to identify new biomarkers linked to poor clinical outcome. HRAS mutations are found in skin papillomas and cSCCs and increase in frequency when MAP3K family members are inhibited, suggesting a link between blockade of mitogen-activated protein kinase (MAPK) signaling and initiation of RAS-primed cells. Tpl2, a MAP3K gene, can serve as a tumor suppressor gene in cSCC. We have previously shown that upon Tpl2 ablation, mice have heightened sensitivity to aberrant RAS signaling. Tpl2-/- mice display significantly higher numbers of papillomas and cSCCs in two-stage chemical carcinogenesis studies and increased tumorigenicity of keratinocytes expressing oncogenic v-rasHa in nude mouse skin grafts. In part, this is mediated through increased mesenchymal-epithelial transition factor (MET) receptor activity. Epidermal Growth Factor Receptor (EGFR) is reported to be an essential factor for MET-driven carcinogenesis and MET activation may confer resistance to EGFR therapies, suggesting that the concurrent use of both an EGFR inhibitor and a MET inhibitor may show promise in advanced cSCCs. In this study we assessed whether normal or Ras-transformed Tpl2-/- keratinocytes have aberrant EGFR signaling and whether concomitant treatment with EGFR/MET tyrosine kinase inhibitors was more effective than single agents in reducing growth and angiogenic potential of Ras-transformed keratinocytes. Tpl2-/- keratinocytes exhibited increased HER-2 and STAT-3 under basal conditions and elevated p-MET and p-EGFR when transduced with oncogenic RAS. Inhibition of MET by Capmatinib increased p-EGFR in Tpl2-/- keratinocytes and papillomas, and inhibition of EGFR by Gefitinib increased HER2 and HER3 signaling in both genotypes. Treatment of keratinocytes with EGFR and MET inhibitors, in combination, significantly enhanced endothelial tube formation, MMP-9 activity and activation of other RTKs, with more pronounced effects when Tpl2 was ablated. These data indicate that Tpl2 cross-talks with both EGFR and MET signaling pathways. Upon inhibition of EGFR/MET signaling, a myriad of escape mechanisms exists in keratinocytes to overcome targeted drug effects.
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Affiliation(s)
- Mary B. Kelley
- Department of Biology, American University, Washington, DC, United States of America
| | - Taylor J. Geddes
- Department of Biology, American University, Washington, DC, United States of America
| | - Maria Ochiai
- Department of Biology, American University, Washington, DC, United States of America
| | - Noah M. Lampl
- Department of Biology, American University, Washington, DC, United States of America
| | - W. Wade Kothmann
- Department of Biology, American University, Washington, DC, United States of America
| | - Sara R. Fierstein
- Department of Biology, American University, Washington, DC, United States of America
| | - Victoria Kent
- Department of Biology, American University, Washington, DC, United States of America
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Ha Thi HT, Kim HY, Lee YJ, Kim SJ, Hong S. SMAD7 in keratinocytes promotes skin carcinogenesis by activating ATM-dependent DNA repair and an EGFR-mediated cell proliferation pathway. Carcinogenesis 2019; 40:112-120. [PMID: 30219864 DOI: 10.1093/carcin/bgy121] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/23/2018] [Accepted: 09/12/2018] [Indexed: 12/22/2022] Open
Abstract
SMA- and MAD-related protein 7 (SMAD7) is a general inhibitor of transforming growth factor-β (TGF-β) signaling that acts through interaction and degradation of TGF-β receptors. SMAD7 has been demonstrated to be transcriptionally upregulated in chemical-induced skin tumors and TGF-β-treated normal keratinocytes. To evaluate the function of SMAD7 in skin carcinogenesis in vivo, Smad7 transgenic mice that specifically express either wild-type (WT) SMAD7 (TG-Smad7-WT) or mutant SMAD7 (TG-Smad7-MT) in keratinocytes, as well as Smad7 keratinocyte-specific knockout (Smad72f/2f-K14Cre) mice, were subjected to chemical-induced skin carcinogenesis. WT-SMAD7-expressing transgenic mice showed significantly greater papilloma formation than did non-TG control and Smad7-MT mice. The expression of WT-SMAD7 attenuated DNA damage-induced apoptosis in epidermal keratinocytes by stimulating the ATM-dependent DNA repair pathway. Nonetheless, overexpression of WT-SMAD7 caused a susceptibility to 12-O-tetradecanoylphorbol-13-acetate-induced epidermal hyperproliferation through activation of epidermal growth factor (EGF) signaling. In agreement with the transgenic mouse data, keratinocyte-specific deletion of SMAD7 markedly suppressed the tumor formation by inhibiting ATM and epidermal growth factor receptor (EGFR) signaling. Moreover, specific inhibition of EGFR signaling attenuated the hyperproliferation and tumor formation in TG-Smad7-WT mice. Taken together, these data support a novel role for SMAD7 as a tumor promoter in skin carcinogenesis where SMAD7 stimulates the DNA repair pathway and EGFR signaling activation.
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Affiliation(s)
- Huyen Trang Ha Thi
- Laboratory of Cancer Cell Biology, Department of Biochemistry, Gachon University School of Medicine, Incheon, Republic of Korea
| | - Hye-Youn Kim
- Laboratory of Cancer Cell Biology, Department of Biochemistry, Gachon University School of Medicine, Incheon, Republic of Korea
| | - Young-Jae Lee
- Laboratory of Developmental Genetics, Department of Biochemistry, Gachon University School of Medicine, Incheon, Republic of Korea
| | - Seong-Jin Kim
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea
| | - Suntaek Hong
- Laboratory of Cancer Cell Biology, Department of Biochemistry, Gachon University School of Medicine, Incheon, Republic of Korea
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Gopalakrishnan T, Ganapathy S, Veeran V, Namasivayam N. Preventive effect of D-carvone during DMBA induced mouse skin tumorigenesis by modulating xenobiotic metabolism and induction of apoptotic events. Biomed Pharmacother 2018; 111:178-187. [PMID: 30583225 DOI: 10.1016/j.biopha.2018.12.071] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/11/2018] [Accepted: 12/15/2018] [Indexed: 12/14/2022] Open
Abstract
The structural integrity and excellent immune system of the skin makes it a protective covering, inspite of its exposure to hazardous compounds. In the present study, the chemopreventive efficacy of D-carvone was studied in 7, 12-dimethylbenz[a]anthracene (DMBA) induced skin carcinogenesis. DMBA (25 μg in 0.1 m L-1acetone) was used to induce skin cancer in Swiss albino mice. Animals were randomly divided into six groups of six animals in each. Different concentrations of D-carvone (10, 20, 30 mg/kg body weight) were used to assess its anticancer effect. Tumor incidence, tumor volume, tumor burden, histological examination and levels of phase I and phase II detoxification agents were analyzed in experimental animals. Further, expression of p53 and various apoptotic proteins including- Bcl-2, Bax was analyzed using immunohistochemistry and enzymatic expression of apoptotic proteins caspase-3 and caspase-9 was carried out by using ELISA. We observed 100% tumor incidence in DMBA-painted animals and our results showed that D-carvone at 20 mg dose significantly prevents skin carcinogenesis. Our results also showed decreased levels of phase I enzymes (Cyt P450 and-Cyt b5) with increased levels of phase II enzymes (GR, GST and GSH) and increased expression of Bax, caspase-3 and caspase-9 with decreased expression of mutated p53 and Bcl-2 in animals treated with DMBA and D-carvone at 20 mg dose. The results of the present study suggest that D-carvone can be used as a chemopreventive agent against skin cancer, as it induces apoptosis in cancer. However, further studies are warranted to check chemopreventive efficacy of D-carvone on cell proliferation, angiogenesis, and metastasis before going to human trial.
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Affiliation(s)
- Thamizharasi Gopalakrishnan
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, 608 002, Tamil Nadu, India
| | - Sindhu Ganapathy
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, 608 002, Tamil Nadu, India.
| | - Veeravarmal Veeran
- Department of Oral & Maxillofacial Pathology, Rajah Muthiah Dental College & Hospital, Annamalai Nagar, 608 002, Tamil Nadu, India
| | - Nalini Namasivayam
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, 608 002, Tamil Nadu, India
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Santinon G, Brian I, Pocaterra A, Romani P, Franzolin E, Rampazzo C, Bicciato S, Dupont S. dNTP metabolism links mechanical cues and YAP/TAZ to cell growth and oncogene-induced senescence. EMBO J 2018; 37:embj.201797780. [PMID: 29650681 DOI: 10.15252/embj.201797780] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 12/20/2022] Open
Abstract
YAP/TAZ, downstream transducers of the Hippo pathway, are powerful regulators of cancer growth. How these factors control proliferation remains poorly defined. Here, we found that YAP/TAZ directly regulate expression of key enzymes involved in deoxynucleotide biosynthesis and maintain dNTP precursor pools in human cancer cells. Regulation of deoxynucleotide metabolism is required for YAP-induced cell growth and underlies the resistance of YAP-addicted cells to chemotherapeutics targeting dNTP synthesis. During RAS-induced senescence, YAP/TAZ bypass RAS-mediated inhibition of nucleotide metabolism and control senescence. Endogenous YAP/TAZ targets and signatures are inhibited by RAS/MEK1 during senescence, and depletion of YAP/TAZ is sufficient to cause senescence-associated phenotypes, suggesting a role for YAP/TAZ in suppression of senescence. Finally, mechanical cues, such as ECM stiffness and cell geometry, regulate senescence in a YAP-dependent manner. This study indicates that YAP/TAZ couples cell proliferation with a metabolism suited for DNA replication and facilitates escape from oncogene-induced senescence. We speculate that this activity might be relevant during the initial phases of tumour progression or during experimental stem cell reprogramming induced by YAP.
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Affiliation(s)
- Giulia Santinon
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Irene Brian
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Arianna Pocaterra
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Patrizia Romani
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | | | - Silvio Bicciato
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Sirio Dupont
- Department of Molecular Medicine, University of Padova, Padova, Italy
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5
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PAD2 overexpression in transgenic mice augments malignancy and tumor-associated inflammation in chemically initiated skin tumors. Cell Tissue Res 2017; 370:275-283. [PMID: 28766045 DOI: 10.1007/s00441-017-2669-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022]
Abstract
We previously found that transgenic mice overexpressing MMTV-FLAG-hPAD2 (PAD2OE) developed spontaneous skin lesions, with a subset of these lesions progressing to invasive squamous cell carcinoma (SCC). The goal of this report was to better understand the potential mechanisms by which PAD2 overexpression promotes skin cancer. Here, PAD2OE mice were treated with the carcinogen, 9,10-dimethyl-1,2-benzanthracene and with O-tetradecanoylphorbol-13-acetate and then scored for papilloma formation. Additionally, tumor sections were evaluated for evidence of tumor cell invasion and inflammation. We found that the total number of papillomas was significantly increased in PAD2OE mice compared to controls. Histopathologic analysis of the lesions found that in PAD2OE skin tumors progressed to invasive SCC more frequently than controls. Additionally, we found that PAD2OE lesions were highly inflamed, with a dense inflammatory cell infiltrate and an associated increase in nuclear phospho-STAT3 (signal transducer and activator of transcription 3) in the transgenic tumors. These data suggest that overexpression of the hPAD2 transgene in the epidermis increases the malignant conversion rate of benign tumors by promoting an inflammatory microenvironment.
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6
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Lee P, Jiang S, Li Y, Yue J, Gou X, Chen SY, Zhao Y, Schober M, Tan M, Wu X. Phosphorylation of Pkp1 by RIPK4 regulates epidermal differentiation and skin tumorigenesis. EMBO J 2017; 36:1963-1980. [PMID: 28507225 DOI: 10.15252/embj.201695679] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/03/2017] [Accepted: 04/07/2017] [Indexed: 02/06/2023] Open
Abstract
Tissue homeostasis of skin is sustained by epidermal progenitor cells localized within the basal layer of the skin epithelium. Post-translational modification of the proteome, such as protein phosphorylation, plays a fundamental role in the regulation of stemness and differentiation of somatic stem cells. However, it remains unclear how phosphoproteomic changes occur and contribute to epidermal differentiation. In this study, we survey the epidermal cell differentiation in a systematic manner by combining quantitative phosphoproteomics with mammalian kinome cDNA library screen. This approach identified a key signaling event, phosphorylation of a desmosome component, PKP1 (plakophilin-1) by RIPK4 (receptor-interacting serine-threonine kinase 4) during epidermal differentiation. With genome-editing and mouse genetics approach, we show that loss of function of either Pkp1 or Ripk4 impairs skin differentiation and enhances epidermal carcinogenesis in vivo Phosphorylation of PKP1's N-terminal domain by RIPK4 is essential for their role in epidermal differentiation. Taken together, our study presents a global view of phosphoproteomic changes that occur during epidermal differentiation, and identifies RIPK-PKP1 signaling as novel axis involved in skin stratification and tumorigenesis.
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Affiliation(s)
- Philbert Lee
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Shangwen Jiang
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yuanyuan Li
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Jiping Yue
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Xuewen Gou
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Shao-Yu Chen
- Department of Pharmacology and Toxicology, University of Louisville Health Science Center, Louisville, KY, USA
| | - Yingming Zhao
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Markus Schober
- The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY, USA
| | - Minjia Tan
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoyang Wu
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
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7
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Yamamoto H, Ryu J, Min E, Oi N, Bai R, Zykova TA, Yu DH, Moriyama K, Bode AM, Dong Z. TRAF1 Is Critical for DMBA/Solar UVR-Induced Skin Carcinogenesis. J Invest Dermatol 2017; 137:1322-1332. [PMID: 28131816 DOI: 10.1016/j.jid.2016.12.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/27/2016] [Accepted: 12/30/2016] [Indexed: 12/15/2022]
Abstract
TRAF1 is a member of the TRAF protein family, which regulates the canonical and noncanonical NF-κB signaling cascades. Although aberrant TRAF1 expression in tumors has been reported, the role of TRAF1 remains elusive. Here, we report that TRAF1 is required for solar UV-induced skin carcinogenesis. Immunohistochemical analysis showed that TRAF1 expression is up-regulated in human actinic keratosis and squamous cell carcinoma. In vivo studies indicated that TRAF1 expression levels in mouse skin are induced by short-term solar UV irradiation, and a long-term skin carcinogenesis study showed that deletion of TRAF1 in mice results in a significant inhibition of skin tumor formation. Moreover, we show that TRAF1 is required for solar UV-induced extracellular signal-regulated kinase-5 (ERK5) phosphorylation and the expression of AP-1 family members (c-Fos/c-Jun). Mechanistic studies showed that TRAF1 expression enhances the ubiquitination of ERK5 on lysine 184, which is necessary for its kinase activity and AP-1 activation. Overall, our results suggest that TRAF1 mediates ERK5 activity by regulating the upstream effectors of ERK5 and also by modulating its ubiquitination status. Targeting TRAF1 function might lead to strategies for preventing and treating skin cancer.
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Affiliation(s)
- Hiroyuki Yamamoto
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Joohyun Ryu
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Eli Min
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Naomi Oi
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Ruihua Bai
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Tatyana A Zykova
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Dong Hoon Yu
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Kenji Moriyama
- Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Hyogo, Japan
| | - Ann M Bode
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA.
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8
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Svirčev Z, Drobac D, Tokodi N, Mijović B, Codd GA, Meriluoto J. Toxicology of microcystins with reference to cases of human intoxications and epidemiological investigations of exposures to cyanobacteria and cyanotoxins. Arch Toxicol 2017; 91:621-650. [DOI: 10.1007/s00204-016-1921-6] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/15/2016] [Indexed: 10/20/2022]
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9
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Dikovskaya D, Cole JJ, Mason SM, Nixon C, Karim SA, McGarry L, Clark W, Hewitt RN, Sammons MA, Zhu J, Athineos D, Leach JDG, Marchesi F, van Tuyn J, Tait SW, Brock C, Morton JP, Wu H, Berger SL, Blyth K, Adams PD. Mitotic Stress Is an Integral Part of the Oncogene-Induced Senescence Program that Promotes Multinucleation and Cell Cycle Arrest. Cell Rep 2015; 12:1483-96. [PMID: 26299965 PMCID: PMC4562906 DOI: 10.1016/j.celrep.2015.07.055] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 06/22/2015] [Accepted: 07/27/2015] [Indexed: 12/18/2022] Open
Abstract
Oncogene-induced senescence (OIS) is a tumor suppression mechanism that blocks cell proliferation in response to oncogenic signaling. OIS is frequently accompanied by multinucleation; however, the origin of this is unknown. Here, we show that multinucleate OIS cells originate mostly from failed mitosis. Prior to senescence, mutant H-RasV12 activation in primary human fibroblasts compromised mitosis, concordant with abnormal expression of mitotic genes functionally linked to the observed mitotic spindle and chromatin defects. Simultaneously, H-RasV12 activation enhanced survival of cells with damaged mitoses, culminating in extended mitotic arrest and aberrant exit from mitosis via mitotic slippage. ERK-dependent transcriptional upregulation of Mcl1 was, at least in part, responsible for enhanced survival and slippage of cells with mitotic defects. Importantly, mitotic slippage and oncogene signaling cooperatively induced senescence and key senescence effectors p21 and p16. In summary, activated Ras coordinately triggers mitotic disruption and enhanced cell survival to promote formation of multinucleate senescent cells.
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Affiliation(s)
- Dina Dikovskaya
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK.
| | - John J Cole
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK
| | - Susan M Mason
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - Colin Nixon
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - Saadia A Karim
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - Lynn McGarry
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - William Clark
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - Rachael N Hewitt
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK
| | - Morgan A Sammons
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Jiajun Zhu
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | | | - Joshua D G Leach
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1BD, UK
| | - Francesco Marchesi
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1BD, UK
| | - John van Tuyn
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK
| | - Stephen W Tait
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK
| | - Claire Brock
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK
| | | | - Hong Wu
- Fox Chase Cancer Center, Philadelphia, PA 19111-2497, USA
| | - Shelley L Berger
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Karen Blyth
- Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
| | - Peter D Adams
- Institute of Cancer Sciences, CR-UK Beatson Laboratories, University of Glasgow, Glasgow G61 1BD, UK.
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Schwarz M, Thielmann HW, Meischner V, Fartasch M. Relevance of the mouse skin initiation-promotion model for the classification of carcinogenic substances encountered at the workplace. Regul Toxicol Pharmacol 2015; 72:150-7. [PMID: 25846367 DOI: 10.1016/j.yrtph.2015.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/25/2015] [Accepted: 03/31/2015] [Indexed: 11/29/2022]
Abstract
The Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission of the Deutsche Forschungsgemeinschaft) evaluates chemical substances using scientific criteria to prevent adverse effects on health at the work place. As part of this task there is a need to evaluate tumor promoting activity of chemicals (enhancement of formation of squamous cell carcinomas via premalignant papillomas) obtained from two-stage initiation/promotion experiments using the mouse skin model. In the present communication we address this issue by comparing responses seen in mouse skin with those in humans. We conclude that tumor promotional effects seen in such animal models be carefully analyzed on a case by case basis. Substances that elicit a rather non-specific effect that is restricted to the high dose range are considered to be irrelevant to humans and thus do not require classification as carcinogens. In contrast, substances that might have both a mode of action and a potency similar to the specific effects seen with TPA (12-O-tetradecanoylphorbol-13-acetate), the prototype tumor promoter in mouse skin, which triggers receptor-mediated signal cascades in the very low dose range, have to be classified in a category for carcinogens.
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Affiliation(s)
- Michael Schwarz
- Eberhard Karls University of Tübingen, Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany.
| | - Heinz W Thielmann
- German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
| | - Veronika Meischner
- Scientific Secretariat of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission), Hohenbachernstr. 15-17, D-85354 Freising-Weihenstephan, Germany
| | - Manigé Fartasch
- Ruhr University Bochum, Institute for Prevention and Occupational Medicine of the DGUV, Department for Clinical and Experimental Occupational Dermatology, Bürkle-de-la-Camp-Platz 1, D-44789 Bochum, Germany
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11
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Kasem RF, Hegazy RH, Arafa MAA, AbdelMohsen MM. Chemopreventive effect of Mentha piperita on dimethylbenz[a
]anthracene and formaldehyde-induced tongue carcinogenesis in mice (histological and immunohistochemical study). J Oral Pathol Med 2014; 43:484-91. [DOI: 10.1111/jop.12150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Rehab F. Kasem
- Faculty of Oral & Dental Medicine; Department of Oral Pathology; Cairo University; Cairo Egypt
| | - Radwa H. Hegazy
- Faculty of Oral & Dental Medicine; Department of Oral Biology; Cairo University; Cairo Egypt
| | - Mona A. A. Arafa
- Faculty of Medicine for Girls; Department of Anatomy; Al-Azhar University; Cairo Egypt
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12
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Svirčev Z, Drobac D, Tokodi N, Lužanin Z, Munjas AM, Nikolin B, Vuleta D, Meriluoto J. Epidemiology of cancers in Serbia and possible connection with cyanobacterial blooms. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2014; 32:319-337. [PMID: 25436472 DOI: 10.1080/10590501.2014.967053] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cyanobacteria produce toxic metabolites known as cyanotoxins. These bioactive compounds can cause acute poisoning, and some of them may promote cancer through chronic exposure. Direct ingestion of and contact with contaminated water is one of the many exposure routes to cyanotoxins. The aim of this article was to review the incidence of 13 cancers during a 10-year period in Serbia and to assess whether there is a correlation between the cancer incidences and cyanobacterial bloom occurrence in reservoirs for drinking water supply. The types of cancers were chosen and subjected to epidemiological analyses utilizing previously published data. Based on the epidemiological and statistical analysis, the group of districts in which the incidences of cancers are significant, and may be considered as critical, include Nišavski, Toplički, and Šumadijski district. A significantly higher incidence of ten cancers was observed in the three critical districts as compared to the remaining 14 districts in Central Serbia. These elevated incidences of cancer include: brain cancer, heart, mediastinum and pleura cancer, ovary cancer, testicular cancer, gastric cancer, colorectal cancer, retroperitoneum and peritoneum cancer, leukemia, malignant melanoma of skin, and primary liver cancer. In addition, the mean incidence of five chosen cancers was the highest in the three critical regions, then in the rest of Central Serbia, while the lowest values were recorded in Vojvodina. Persistent and recurrent cyanobacterial blooms occur during summer months in reservoirs supplying water to waterworks in the three critical districts. People in Central Serbia mainly use surface water as water supply (but not all the water bodies are blooming) while in Vojvodina region (control region in this study) only groundwater is used. Among the 14 "noncritical" districts, reservoirs used for drinking water supply have been affected by recurrent cyanobacterial blooms in two districts (Rasinski and Zaječarski), but the waterworks in these districts have been performing ozonation for more than 30 years. We propose that the established statistical differences of cancer incidences in Serbia could be related to drinking water quality, which is affected by cyanobacterial blooms in drinking water reservoirs in certain districts. However, more detailed research is needed regarding cyanobacterial secondary metabolites as risk factors in tumor promotion and cancerogenesis in general.
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Affiliation(s)
- Zorica Svirčev
- a Department of Biology and Ecology, Faculty of Sciences , University of Novi Sad , Novi Sad , Serbia
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Tumor promoters: from chemicals to inflammatory proteins. J Cancer Res Clin Oncol 2013; 139:1603-14. [PMID: 23756937 DOI: 10.1007/s00432-013-1455-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/25/2013] [Indexed: 01/29/2023]
Abstract
PURPOSE The classic two-stage chemical carcinogenesis in rodents is not directly linked to multistage carcinogenesis in humans. In light of our findings that tumor necrosis factor-α (TNF-α) is an endogenous tumor promoter and that TNF-α-inducing protein (Tipα) of Helicobacter pylori stimulates progression of cancer and epithelial-mesenchymal transition, we think it is necessary to re-examine the concept of tumor promoter, from chemicals to inflammatory proteins. TOPICS AND RESULTS This paper begins with "inflammation," discovered by Virchow, studies of Yamagiwa and Tsutsui, and briefly reviews numerous topics, such as (1) the classic concept of tumor promoter, (2) tumor promotion on mouse skin induced by protein kinase C activators and okadaic acid class compounds, (3) organ specificity of tumor promoters, presenting numerous tumor promoters in various organs, (4) unique tumor promotion induced by inhibitors of protein phosphatases 1 and 2A in mouse skin, rat glandular stomach, and rat liver, (5) the significant role of TNF-α in tumor-promoting inflammation, (6) progression induced by Tipα of H. pylori, and (7) enhancement of cancer treatment efficacy with the combination of anticancer drugs and green tea catechins, to inhibit tumor-promoting inflammation. CONCLUSION Human cancer development involves both durable genetic changes caused by carcinogens and proinflammatory cytokines, and simultaneous inflammation in progression induced by proinflammatory cytokines and chemokines.
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IQGAP1 scaffold-kinase interaction blockade selectively targets RAS-MAP kinase-driven tumors. Nat Med 2013; 19:626-630. [PMID: 23603816 DOI: 10.1038/nm.3165] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/14/2013] [Indexed: 12/16/2022]
Abstract
Upregulation of the ERK1 and ERK2 (ERK1/2) MAP kinase (MAPK) cascade occurs in >30% of cancers, often through mutational activation of receptor tyrosine kinases or other upstream genes, including KRAS and BRAF. Efforts to target endogenous MAPKs are challenged by the fact that these kinases are required for viability in mammals. Additionally, the effectiveness of new inhibitors of mutant BRAF has been diminished by acquired tumor resistance through selection for BRAF-independent mechanisms of ERK1/2 induction. Furthermore, recently identified ERK1/2-inducing mutations in MEK1 and MEK2 (MEK1/2) MAPK genes in melanoma confer resistance to emerging therapeutic MEK inhibitors, underscoring the challenges facing direct kinase inhibition in cancer. MAPK scaffolds, such as IQ motif-containing GTPase activating protein 1 (IQGAP1), assemble pathway kinases to affect signal transmission, and disrupting scaffold function therefore offers an orthogonal approach to MAPK cascade inhibition. Consistent with this, we found a requirement for IQGAP1 in RAS-driven tumorigenesis in mouse and human tissue. In addition, the ERK1/2-binding IQGAP1 WW domain peptide disrupted IQGAP1-ERK1/2 interactions, inhibited RAS- and RAF-driven tumorigenesis, bypassed acquired resistance to the BRAF inhibitor vemurafenib (PLX-4032) and acted as a systemically deliverable therapeutic to significantly increase the lifespan of tumor-bearing mice. Scaffold-kinase interaction blockade acts by a mechanism distinct from direct kinase inhibition and may be a strategy to target overactive oncogenic kinase cascades in cancer.
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Viarisio D, Decker KM, Aengeneyndt B, Flechtenmacher C, Gissmann L, Tommasino M. Human papillomavirus type 38 E6 and E7 act as tumour promoters during chemically induced skin carcinogenesis. J Gen Virol 2012; 94:749-752. [PMID: 23223623 DOI: 10.1099/vir.0.048991-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many findings support a possible involvement of a subgroup of human papillomaviruses (HPVs), called cutaneous beta HPV types, in the development of non-melanoma skin cancer. The skin of transgenic (Tg) mice expressing viral oncoproteins E6 and E7 from different cutaneous beta HPV types, including HPV38, showed an increased susceptibility to UV-induced and/or chemically induced skin carcinogenesis compared with wild-type animals. In this study, we show that beta HPV38 E6 and E7 oncoproteins act as promoter and progression factors in multi-stage skin carcinogenesis, strongly cooperating with the initiator and DNA damage agent 7,12-dimethylbenz[a]anthracene. In contrast, exposure of HPV38 E6/E7 Tg mice to the promoter 12-O-tetradecanoylphorbol-13-acetate did not significantly result in the development of skin lesions. These findings further support the role of beta HPV types in skin carcinogenesis, providing additional insight into their precise contribution to the multi-step process.
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Affiliation(s)
| | | | | | | | - Lutz Gissmann
- Department of Botany and Microbiology (honorary member), King Saud University, Riyadh, Saudi Arabia.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Massimo Tommasino
- International Agency for Research on Cancer, World Health Organization, Lyon, France
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Fujiki H, Suganuma M. Carcinogenic aspects of protein phosphatase 1 and 2A inhibitors. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:221-54. [PMID: 19184590 DOI: 10.1007/978-3-540-87895-7_8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Okadaic acid is functionally a potent tumor promoter working through inhibition of protein phosphatases 1 and 2A (PP1 and PP2A), resulting in sustained phosphorylation of proteins in cells. The mechanism of tumor promotion with okadaic acid is thus completely different from that of the classic tumor promoter phorbol ester. Other potent inhibitors of PP1 and PP2A - such as dinophysistoxin-1, calyculins A-H, microcystin-LR and its derivatives, and nodularin - were isolated from marine organisms, and their structural features including the crystal structure of the PP1-inhibitor complex, tumor promoting activities, and biochemical and biological effects, are here reviewed. The compounds induced tumor promoting activity in three different organs, including mouse skin, rat glandular stomach and rat liver, initiated with three different carcinogens. The results indicate that inhibition of PP1 and PP2A is a general mechanism of tumor promotion applicable to various organs. This study supports the concept of endogenous tumor promoters in human cancer development.
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Affiliation(s)
- Hirota Fujiki
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
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Li H, Xie P, Li G, Hao L, Xiong Q. In vivo study on the effects of microcystin extracts on the expression profiles of proto-oncogenes (c-fos, c-jun and c-myc) in liver, kidney and testis of male Wistar rats injected i.v. with toxins. Toxicon 2009; 53:169-75. [DOI: 10.1016/j.toxicon.2008.10.027] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/27/2008] [Accepted: 10/28/2008] [Indexed: 01/21/2023]
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18
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Fujiki H, Suganuma M. Naturally-Derived Tumor Promoters and Inhibitors of Carcinogenesis. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569549609064081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Paul VJ, Arthur KE, Ritson-Williams R, Ross C, Sharp K. Chemical defenses: from compounds to communities. THE BIOLOGICAL BULLETIN 2007; 213:226-251. [PMID: 18083964 DOI: 10.2307/25066642] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Marine natural products play critical roles in the chemical defense of many marine organisms and in some cases can influence the community structure of entire ecosystems. Although many marine natural products have been studied for biomedical activity, yielding important information about their biochemical effects and mechanisms of action, much less is known about ecological functions. The way in which marine consumers perceive chemical defenses can influence their health and survival and determine whether some natural products persist through a food chain. This article focuses on selected marine natural products, including okadaic acid, brevetoxins, lyngbyatoxin A, caulerpenyne, bryostatins, and isocyano terpenes, and examines their biosynthesis (sometimes by symbiotic microorganisms), mechanisms of action, and biological and ecological activity. We selected these compounds because their impacts on marine organisms and communities are some of the best-studied among marine natural products. We discuss the effects of these compounds on consumer behavior and physiology, with an emphasis on neuroecology. In addition to mediating a variety of trophic interactions, these compounds may be responsible for community-scale ecological impacts of chemically defended organisms, such as shifts in benthic and pelagic community composition. Our examples include harmful algal blooms; the invasion of the Mediterranean by Caulerpa taxifolia; overgrowth of coral reefs by chemically rich macroalgae and cyanobacteria; and invertebrate chemical defenses, including the role of microbial symbionts in compound production.
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Affiliation(s)
- Valerie J Paul
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Fort Pierce, Florida 34949, USA.
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20
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Chakravarti D, Venugopal D, Mailander PC, Meza JL, Higginbotham S, Cavalieri EL, Rogan EG. The role of polycyclic aromatic hydrocarbon-DNA adducts in inducing mutations in mouse skin. Mutat Res 2007; 649:161-78. [PMID: 17931959 DOI: 10.1016/j.mrgentox.2007.08.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 08/17/2007] [Accepted: 08/31/2007] [Indexed: 11/29/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAH) form stable and depurinating DNA adducts in mouse skin to induce preneoplastic mutations. Some mutations transform cells, which then clonally expand to establish tumors. Strong clues about the mutagenic mechanism can be obtained if the PAH-DNA adducts can be correlated with both preneoplastic and tumor mutations. To this end, we studied mutagenesis in PAH-treated early preneoplastic skin (1 day after exposure) and in the induced papillomas in SENCAR mice. Papillomas were studied by PCR amplification of the H-ras gene and sequencing. For benzo[a]pyrene (BP), BP-7,8-dihydrodiol (BPDHD), 7,12-dimethylbenz[a]anthracene (DMBA) and dibenzo[a,l]pyrene (DB[a,l]P), the codon 13 (GGC to GTC) and codon 61 (CAA to CTA) mutations in papillomas corresponded to the relative levels of Gua and Ade-depurinating adducts, despite BP and BPDHD forming significant amounts of stable DNA adducts. Such a relationship was expected for DMBA and DB[a,l]P, as they formed primarily depurinating adducts. These results suggest that depurinating adducts play a major role in forming the tumorigenic mutations. To validate this correlation, preneoplastic skin mutations were studied by cloning H-ras PCR products and sequencing individual clones. DMBA- and DB[a,l]P-treated skin showed primarily A.T to G.C mutations, which correlated with the high ratio of the Ade/Gua-depurinating adducts. Incubation of skin DNA with T.G-DNA glycosylase eliminated most of these A.T to G.C mutations, indicating that they existed as G.T heteroduplexes, as would be expected if they were formed by errors in the repair of abasic sites generated by the depurinating adducts. BP and its metabolites induced mainly G.C to T.A mutations in preneoplastic skin. However, PCR over unrepaired anti-BPDE-N(2)dG adducts can generate similar mutations as artifacts of the study protocol, making it difficult to establish an adduct-mutation correlation for determining which BP-DNA adducts induce the early preneoplastic mutations. In conclusion, this study suggests that depurinating adducts play a major role in PAH mutagenesis.
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Filler RB, Roberts SJ, Girardi M. Cutaneous two-stage chemical carcinogenesis. ACTA ACUST UNITED AC 2007; 2007:pdb.prot4837. [PMID: 21357170 DOI: 10.1101/pdb.prot4837] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTIONThe induction of cutaneous carcinogenesis in mice by topical administration of chemicals enables the local, systemic, and environmental factors that influence tumor susceptibility, growth, and progression to be studied in the laboratory. Chemical carcinogenesis in mouse skin has been used for several decades, and continues to help in the identification of important molecular and immunological pathways involved in cutaneous malignancy. This protocol describes the two-stage application of chemicals to the skin for the initiation and promotion of cutaneous tumors. In the two-stage model of induction, a single application of the chemical initiator mutagen 7,12-dimethylbenz[a]anthracene (DMBA) is followed by repeated applications of a pro-inflammatory phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA; otherwise known as phorbol 12-myristate 13-acetate [PMA]). Resulting tumors may develop in the form of benign papillomas that regress or progress to SCC, or SCC may arise without an apparent precursor lesion. Thus, two-stage chemical carcinogenesis provides an opportunity to monitor early and late events in cancer development and progression.
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Affiliation(s)
- Renata B Filler
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510, USA
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22
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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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Feng G, Ohmori Y, Chang PL. Production of chemokine CXCL1/KC by okadaic acid through the nuclear factor-kappaB pathway. Carcinogenesis 2005; 27:43-52. [PMID: 16000401 DOI: 10.1093/carcin/bgi174] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The murine chemokine CXCL1/KC is known as a chemoattractant for neutrophil infiltration and as a promoter of tumor growth. To determine its relevance in tumorigenesis, we first asked whether okadaic acid (OKA), a natural tumor promoter and a potent protein phosphatase 1 and 2A inhibitor, stimulates KC expression and if it does, through what pathway, in a promotable mouse epidermal-like JB6 cell line commonly used for studying molecules related to tumor promotion. We found that OKA stimulated the de novo synthesis of KC mRNA and protein in a dose- and time-dependent manner. To determine the mechanism by which OKA stimulated the expression of KC at the transcriptional level, transient transfection assays using serially deleted sections of KC promoter fused to luciferase reporter gene were performed. These studies showed that transactivation of KC promoter by OKA specifically involved the region between -104 and -59 containing the two nuclear factor-kappaB (NF-kappaB) response elements (kappaB1 and kappaB2). Further analyses using the mutated NF-kappaB response elements kappaB1 and kappaB2 indicated that both regions were required for optimum transactivation of KC by OKA with the former NF-kappaB response element playing a more significant role in regulating KC expression. Gel-shift and supershift analyses demonstrated the involvement of three NF-kappaB subunits, p65, p50 and c-Rel, with p65 as the major subunit in the NF-kappaB dimer complex. Additionally, immunohistochemistry and western blot analyses confirmed the presence of p65 in the nucleus with its transactivation domain phosphorylated at serine 536. In summary, this is the first report to show that the tumor promoter OKA can stimulate the de novo synthesis and secretion of KC, and that this stimulation is mediated through the NF-kappaB pathway in JB6 cells.
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Affiliation(s)
- Gong Feng
- Department of Nutrition Sciences and Comprehensive Cancer Center, University of Alabama at Birmingham, AL 35294-3360, USA
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Elegbede JA, Hayes K, Schell K, Oberley TD, Verma AK. Induction of apoptosis and inhibition of papilloma formation may signal a new role for okadaic acid. Life Sci 2002; 71:421-36. [PMID: 12044842 DOI: 10.1016/s0024-3205(02)01701-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Okadaic acid (OA), a tumor promoter in the mouse skin carcinogenesis model, has been shown to induce apoptosis in tumor cell lines that harbor H-ras mutations. We examined the effects of OA on mouse keratinocytes with (308) and without (C50) H-ras mutation in vitro and in an in vivo system. Following exposure to varying concentrations of OA over time, the effects of OA in vitro were assessed using microscopic, biochemical and flow cytometric techniques. OA effects on the cells included incorporation of propidium iodide, externalization of phosphatidylserine, and development of hypodiploidy. 308 cells demonstrated typical DNA ladder formation, rapid chromatin and nuclear condensation, while C50 cells demonstrated delayed chromatin condensation and nuclear fragmentation, but no DNA ladder formation. In vivo, OA elicited delayed papilloma formation and reduced tumor multiplicity. Though its mechanism of action is not fully known, we found that OA-induced inhibition of the clonal expansion of initiated cells may be related to the presence or absence of H-ras mutation.
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Affiliation(s)
- J Abiodun Elegbede
- Chemistry Department and UNLV Cancer Institute, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4003, USA.
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Arber N, Shapira I, Ratan J, Stern B, Hibshoosh H, Moshkowitz M, Gammon M, Fabian I, Halpern Z. Activation of c-K-ras mutations in human gastrointestinal tumors. Gastroenterology 2000; 118:1045-50. [PMID: 10833479 DOI: 10.1016/s0016-5085(00)70357-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Ras genes are the most frequently detected oncogenes in human malignancies. Data regarding the frequency of c-K-ras mutations in esophageal, gastric, and small bowel tumors are limited and controversial. METHODS DNA was extracted from 262 formalin-fixed, paraffin-embedded sections of gastrointestinal samples and tumors, including Barrett's esophagus, esophageal squamous cell carcinomas and adenocarcinomas, and small and large bowel adenomas and adenocarcinomas. The presence of c-K-ras codon 12 mutations was determined using a nonradioactive polymerase chain reaction-based restriction fragment length polymorphism assay. RESULTS c-K-ras mutations were detected in 1 of 39 (2%) patients with Barrett's esophagus, 1 of 21 (5%) adenocarcinomas, 0 of 27 squamous cell carcinomas of the esophagus, and 1 of 32 (3%) gastric adenocarcinomas. It was also present in 8 of 20 (40%) and 10 of 28 (36%) small bowel adenomas and adenocarcinomas, respectively. Similar numbers were observed in 10 of 25 (40%) large bowel adenomas and 11 of 30 adenocarcinomas (37%). Mutations were not associated with age, gender, histology, grade, stage, location, or mortality. CONCLUSIONS The frequency of codon 12 c-K-ras mutations in small and large bowel tumors is approximately 10-fold higher than that of tumors in the upper gastrointestinal tract.
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Affiliation(s)
- N Arber
- GI Oncology Unit, Tel-Aviv University, Tel Aviv, Israel.
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Rehman I, Lowry DT, Adams C, Abdel-Fattah R, Holly A, Yuspa SH, Hennings H. Frequent codon 12 Ki-ras mutations in mouse skin tumors initiated byN-methyl-N?-nitro-N-nitrosoguanidine and promoted by mezerein. Mol Carcinog 2000. [DOI: 10.1002/(sici)1098-2744(200004)27:4<298::aid-mc8>3.0.co;2-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
In Asia, nontoxic dietary products are considered desirable primary prevention vehicles for conquering cancer. As early as 1978, investigators in Korea carried out extensive long-term anticarcinogenicity experiments using the mouse lung tumor model and observed an anticarcinogenic effect of Panax ginseng C.A. Meyer extract in 1980. The results showed that natural products can provide hope for human cancer prevention. A newly established nine-week medium-term model using mouse lung tumors (Yun's model) could confirm the anticarcinogenicity of ginseng that varies according to its type and age. Subsequently, the ginseng was shown by epidemiological studies to be a nonorgan-specific cancer preventive agent associated with a dose-response relationship. The anticarcinogenic effects of vegetarian foods common at every dining table in Korea and some synthetics were also studied using Yun's nine-week model. In brief, ascorbic acid, soybean lecithin, capsaicin, biochanin A, Ganoderma lucidum, caffeine, and a novel synthetic 2-(allylthio)pyrazine decrease the incidence of mouse lung tumors, whereas fresh ginseng (4 years old), carrot, spinach, Sesamum indicum, beta-carotene, and 13-cis retinoic acid do not. This result regarding beta-carotene is consistent with the ineffective findings of the ATBC trial, the CARET trial, and the Physicians' Health Study. In 1983, a cancer chemoprevention study group was first established in Japan. Subsequently, (-)-epigallocatechin gallate, cryptoporic acid E, and sarcophytol A from natural products, and synthetic acyclic retinoid and canventol were shown to be anticarcinogenic or chemopreventive in human subjects. Despite the frequent consumption of tea wordwide as a beverage and current experimental evidence of anticarcinogenesis, including controversial results of epidemiological studies, more systematic clinical trials for confirmation of preventive activity of tea against cancer are needed. Placebo-controlled intervention trials of dietary fiber are under study in Japan. In the past decade, new triterpenoids were isolated from various natural sources, and its biological activities were investigated in Asia. In the late 1970s a comprehensive chemoprevention program was established at the Institute of Materia Medica, Chinese Academy of Medical Sciences. Since then, many retinoid compounds have been synthesized and screened in the search for chemopreventive cancer agents. The National Cancer Institute (USA) and China are jointly engaged in the two-nutrition intervention in Linxian, China. The results of joint study of the general population and of dysplasia in China should stimulate further research to clarify the potential benefits of micronutrient supplements. We need to clarify if there is a connection between the lower rates of cancer mortality in Korea and the frequent consumption of anticarcinogenic vegetables or traditional foods, including ginseng and Ganoderma lucidum. The constituents of the nontoxic stable dietary products promise to be the future hope for conquering cancers in the coming years.
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Affiliation(s)
- T K Yun
- Laboratory of Experimental Pathology, Korea Cancer Center Hospital, Seoul, Korea.
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Mashour GA, Martuza RL, Kurtz A. Induction of melanogenic abnormalities in NF1+/- mutant mice by DMBA. J Invest Dermatol 1999; 113:1133-4. [PMID: 10594763 DOI: 10.1046/j.1523-1747.1999.00813.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Smith AB, Friestad GK, Barbosa J, Bertounesque E, Hull KG, Iwashima M, Qiu Y, Salvatore BA, Spoors PG, Duan JJW. Total Synthesis of (+)-Calyculin A and (−)-Calyculin B: Asymmetric Synthesis of the C(9−25) Spiroketal Dipropionate Subunit. J Am Chem Soc 1999. [DOI: 10.1021/ja992134m] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amos B. Smith
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Gregory K. Friestad
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Joseph Barbosa
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Emmanuel Bertounesque
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kenneth G. Hull
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Makoto Iwashima
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Yuping Qiu
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Brian A. Salvatore
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - P. Grant Spoors
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - James J.-W. Duan
- Contribution from the Department of Chemistry, the Laboratory for Research on the Structure of Matter, and the Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Rajesh D, Schell K, Verma AK. Ras mutation, irrespective of cell type and p53 status, determines a cell's destiny to undergo apoptosis by okadaic acid, an inhibitor of protein phosphatase 1 and 2A. Mol Pharmacol 1999; 56:515-25. [PMID: 10462539 DOI: 10.1124/mol.56.3.515] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Okadaic acid (OA), a toxin from the black sponge Halicondria okadai, is a specific inhibitor of serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A). OA is a tumor promoter but also induces apoptosis in some tumor cell lines. In this study, we determined whether ras mutation and/or p53 status are characteristics associated with the cell's sensitivity to the induction of apoptosis by OA. Several cell lines that differed in ras and p53 mutations were treated with OA (10-100 nM). At 24 to 48 h after treatment, the percentage of cells undergoing apoptosis was quantitated. The cell lines with mutations in either H-ras (human bladder carcinoma cell line T24 and mouse keratinocyte cell line 308), or K-ras (human colon carcinoma cell lines DLD-1 and HCT116; human prostate cancer cell lines LNCaP and PC-3; human lung cancer cell lines Calu-6 and SKLU-1; and human pancreatic cancer cell line MIAPaCa2) were more sensitive to OA-induced apoptosis (3- to 10-fold) than the cell lines that lacked the ras mutation (mouse epidermal cell lines C50 and JB6; murine fibroblast cell line NIH3T3; human colon cancer cell line HT29; human kidney epithelial cell line Hs715.K; and human pancreatic cancer cell line Bx-PC3). Similarly, using isogenic cell lines we found that overexpression of mutated H-ras in NIH3T3 and in SV40 immortalized human uroepithelial cells (SVHUC) enhanced their sensitivity to undergo apoptosis in response to OA treatment. The T24, DLD-1, SKLU-1, Calu-6, and MIAPaCa2 cell lines express mutated p53. The SVHUC as well as their ras-transfected counterparts have inactive p53 due to complex formation between large "T" antigen and p53. Taken together, these results imply that OA-induced apoptosis may involve a p53-independent pathway. The transfectants (NIH3T3-ras and SVHUC-ras), which express mutated H-ras, have up-regulated PP2A activity. OA treatment inhibited in vivo the levels of PP1 and PP2A activity, and induced apoptosis in SVHUC-ras and other cell lines. We conclude that OA-induced cell death pathway in ras-activated cell lines may involve a cross talk between PP1 and PP2A and ras signaling pathways. In light of the present results, the current theory that OA promotes mouse skin tumor formation by selective expansion of initiated cells that harbor ras mutations needs reevaluation.
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Affiliation(s)
- D Rajesh
- Department of Human Oncology, Medical School, University of Wisconsin, Madison, Wisconsin, USA
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31
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Abstract
The role of serine/threonine protein phosphatase type 2A (PP2A) in cellular growth control has not yet been thoroughly established. Earlier experiments with okadaic acid, a phosphatase inhibitor, suggested that PP2A may act as an anti-oncogene, although a direct role for this enzyme in the transformation process has not been demonstrated. We therefore investigated whether altered levels of PP2A expression would affect the transformation of mouse fibroblasts by the Ha-ras oncogene. Here we report that cells with elevated levels of PP2A expression were more resistant to focus formation induced by Ha-ras. At the molecular level, this was paralleled by the reduced Ha-ras-stimulated expression of the c-fos promoter, a proto-oncogene target for Ha-ras signaling. Thus, our results support a negative role for PP2A in the process of cellular transformation and may ascribe tumor-suppressing functions to this enzyme.
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Affiliation(s)
- Z Baharians
- Department of Molecular Microbiology and Immunology, K. Norris Comprehensive Cancer Center, University of Southern California, Los Angeles 90033-1034, USA
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32
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Sheppeck JE, Gauss CM, Chamberlin AR. Inhibition of the Ser-Thr phosphatases PP1 and PP2A by naturally occurring toxins. Bioorg Med Chem 1997; 5:1739-50. [PMID: 9354230 DOI: 10.1016/s0968-0896(97)00146-6] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The okadaic acid class of naturally occurring toxins is a structurally diverse group of molecules that inhibit the protein phosphatases PP1 and PP2A. Studies providing information about the mode of binding between the toxins and the phosphatases contribute to an overall understanding of the signal transduction pathways in which the phosphatases are involved.
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Affiliation(s)
- J E Sheppeck
- Department of Chemistry, University of California at Irvine 92697, USA
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33
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Sutter T, Arber N, Moss SF, Findling RI, Neugut AI, Weinstein IB, Holt PR. Frequent K-ras mutations in small bowel adenocarcinomas. Dig Dis Sci 1996; 41:115-8. [PMID: 8565742 DOI: 10.1007/bf02208591] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reasons for the relatively rare occurrence of small bowel adenocarcinomas when compared to the high frequency of colonic adenocarcinomas are unknown. Activating mutations in the K-ras oncogene occur in about 40% of colonic adenocarcinomas, possibly reflecting the consequences of carcinogenic exposure. To study whether the low incidence of small bowel adenocarcinomas might be due to the absence of activation of cellular oncogenes in small bowel adenocarcinomas, we examined the frequency of K-ras mutations in small bowel adenocarcinomas. K-ras mutations were determined using a polymerase chain reaction (PCR)-based method to detect codon 12 mutations by restriction fragment length polymorphism. PCR amplification was successful in six of nine small bowel adenocarcinoma samples, and revealed point mutations of K-ras at codon 12 in five of these six cases. We conclude that the small bowel might be exposed to carcinogens similar to those responsible for colorectal cancer, but may have developed protective mechanisms against cancer formation.
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Affiliation(s)
- T Sutter
- Columbia-Presbyterian Cancer Center, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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34
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Yamasaki H. Non-genotoxic mechanisms of carcinogenesis: studies of cell transformation and gap junctional intercellular communication. Toxicol Lett 1995; 77:55-61. [PMID: 7618169 DOI: 10.1016/0378-4274(95)03272-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
It is widely accepted that a series of genetic changes accumulate during carcinogenesis. In addition, it is likely that various non-genotoxic mechanisms also operate at different stages of carcinogenesis. It is even possible that non-genotoxic mechanisms indirectly generate genetic changes, e.g., through induction of cell proliferation, active oxygen species or cytosine methylation. This may partially explain why many carcinogens are devoid of activity when tested in the usual genetic toxicology assays. In vitro cell transformation mimics certain stages of in vivo carcinogenesis. It has therefore been proposed that both genotoxic and non-genotoxic aspects of carcinogenesis can be studied in cell transformation systems, with tumor formation by transformed cells in syngenic animals or nude mice as the endpoint. Many genotoxic as well as non-genotoxic carcinogens induce transformation of Syrian hamster embryo, murine Balb/c 3T3 and murine C3H10T1/2 cells; interaction of genotoxic and non-genotoxic mechanisms can be clearly seen in 2-stage cell transformation studies in which a genotoxic initiating agent and a non-genotoxic promoting agent act synergistically to induce transformation of rodent cells. Aberrant control of gap junctional intercellular communication (GJIC) in cell transformation and carcinogenesis is well documented. Possible genotoxic as well as non-genotoxic mechanisms involved in abnormal gap junction communication control in multistage carcinogenesis are discussed.
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Affiliation(s)
- H Yamasaki
- International Agency for Research on Cancer, Lyon, France
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35
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Tsutsumi M, Murakami Y, Kondoh S, Tsujiuchi T, Hohnoki K, Horiguchi K, Noguchi O, Kobayashi E, Okita S, Sekiya T. Comparison of K-ras oncogene activation in pancreatic duct carcinomas and cholangiocarcinomas induced in hamsters by N-nitrosobis(2-hydroxypropyl)amine. Jpn J Cancer Res 1993; 84:956-60. [PMID: 8407562 PMCID: PMC5919290 DOI: 10.1111/j.1349-7006.1993.tb00184.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The presence of K-ras point mutations in pancreatic duct carcinomas and cholangiocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) in Syrian hamsters was investigated by single-strand conformation polymorphism analysis of polymerase chain reaction products from frozen fresh materials in order to clarify the K-ras mutation rates in those two carcinomas induced simultaneously by one carcinogen, BHP. In the examined pancreatic duct carcinomas, 10 out of 16 were positive for a mutation in codon 12 while 3 out of 12 cholangiocarcinomas demonstrated mutation of K-ras gene. G-to-A transition was detected in the second position of codon 12 in both pancreatic carcinomas and cholangiocarcinomas. These results suggest that the role of genetic alteration in carcinogenesis may differ with the target organ, even when initiation is with the same carcinogen.
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Affiliation(s)
- M Tsutsumi
- Department of Oncological Pathology, Nara Medical University
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36
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Fujiki H, Suganuma M. Tumor promotion by inhibitors of protein phosphatases 1 and 2A: the okadaic acid class of compounds. Adv Cancer Res 1993; 61:143-94. [PMID: 8394044 DOI: 10.1016/s0065-230x(08)60958-6] [Citation(s) in RCA: 241] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- H Fujiki
- Cancer Prevention Division, National Cancer Center Research Institute, Tokyo, Japan
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37
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Yamasaki H, Mesnil M, Nakazawa H. Interaction and distinction of genotoxic and non-genotoxic events in carcinogenesis. Toxicol Lett 1992; 64-65 Spec No:597-604. [PMID: 1471213 DOI: 10.1016/0378-4274(92)90237-e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Multistage carcinogenesis involves genotoxic as well as non-genotoxic mechanisms. The importance of genotoxic events in human carcinogenesis is apparent from the analysis of tumours: for example, five to six genetic alterations can be found in most malignant colorectal tumours. While such measurable "footprints" (e.g. ras, p53 mutations) can be left in tumours by genotoxic events, non-genotoxic events cannot directly generate them. Thus, the lack of specific indicators of non-genotoxic events in carcinogenesis makes the identification of non-genotoxic carcinogens difficult. It is also important to emphasize that apparent "genotoxic" endpoints (mutations, chromosome aberrations) could be induced by "non-genotoxic" agents through indirect mechanisms (e.g. induced cell proliferation and/or genomic instability, oxidative damage, deamination of 5-methyl cytosine). This emphasizes the need for differentiating "events" from the actual "activities" of chemicals and the difficulty of classification of carcinogens into genotoxic and non-genotoxic. One of the best models for the study of interaction of genotoxic and non-genotoxic mechanisms during carcinogenesis is a two-stage carcinogenesis system using mouse skin, rat liver or cultured cells. Molecular analysis of tumours produced on mouse skin by the classical initiation-promotion protocol indicates that the mutation spectra of oncogenes, e.g. Ha-ras, are determined by initiating (genotoxic) and not by promoting (non-genotoxic) agents. However, since usually no tumours appear without the application of tumour-promoting agents, the manifestation of genotoxic events (Ha-ras mutation) is dependent on the action of non-genotoxic agents. Using a BALB c 3T3 two-stage cell transformation system, we have now succeeded in confirming this and have quantitated the initiation and promotion events. These studies may help us not only in understanding mechanisms of carcinogenesis but also in developing molecular quantitative risk assessment in terms of multistage carcinogenesis.
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Affiliation(s)
- H Yamasaki
- Unit of Multistage Carcinogenesis, International Agency for Research on Cancer, Lyon, France
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38
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Nishiwaki-Matsushima R, Ohta T, Nishiwaki S, Suganuma M, Kohyama K, Ishikawa T, Carmichael WW, Fujiki H. Liver tumor promotion by the cyanobacterial cyclic peptide toxin microcystin-LR. J Cancer Res Clin Oncol 1992; 118:420-4. [PMID: 1618889 DOI: 10.1007/bf01629424] [Citation(s) in RCA: 626] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Certain waterblooms of toxic cyanobacteria (blue-green algae) are a health threat because of their production of toxic peptides, termed microcystins, which cause liver damage in wild and domesticated animals. The most widely studied microcystin is microcystin-LR, a heptapeptide containing the two L-amino acids, leucine and arginine. The inhibition of protein phosphatase type 1 and type 2A activities by microcystin-LR is similar to that of the known protein phosphatase inhibitor and tumor promoter okadaic acid. We show in this report that microcystin-LR, applied below the acute toxicity level, dose-dependently increases the number and percentage area of positive foci for the placental form of glutathione S-transferase in rat liver, which was initiated with diethylnitrosamine. The result was obtained independently through two animal experiments. This observation indicates that microcystin-LR is a new liver tumor promoter mediated through inhibition of protein phosphatase type 1 and type 2A activities. This provides further evidence that the okadaic acid pathway is a general mechanism of tumor promotion in various organs, such as mouse skin, rat glandular stomach and rat liver.
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39
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Fujiki H. Is the inhibition of protein phosphatase 1 and 2A activities a general mechanism of tumor promotion in human cancer development? Mol Carcinog 1992; 5:91-4. [PMID: 1313239 DOI: 10.1002/mc.2940050202] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- H Fujiki
- Cancer Prevention Division, National Cancer Center Research Institute, Tokyo, Japan
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40
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Koskinen AM, Chen J. Enantiospecific synthesis of polyhydroxy amino acids. Synthesis of the C33C38 portion of calyculins. Tetrahedron Lett 1991. [DOI: 10.1016/0040-4039(91)80459-j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Smith AB, Duan JJW, Hull KG, Salvatore BA. Calyculin synthetic studies. Stereoselective construction of the C(14)-C(25) spiroketal subunit. Tetrahedron Lett 1991. [DOI: 10.1016/s0040-4039(00)93479-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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43
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Xu LZ, Larzul D. The polymerase chain reaction: basic methodology and applications. Comp Immunol Microbiol Infect Dis 1991; 14:209-21. [PMID: 1959316 DOI: 10.1016/0147-9571(91)90001-t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The "polymerase chain reaction" (PCR) is a high-power molecular biology technique allowing in vitro enzymatic amplification of a given DNA sequence. This exponential amplification can reach 10(7)-10(9), even a single DNA molecule can be detected. Also the use of non-radioactive probes, considered to be less sensitive than their radioactive counterparts, is possible for the molecular hybridization, to retain a high level of sensitivity. PCR is defined as a "free bacteria" cloning technique, which has many applications in fundamental research and in the clinical analysis of genetic disease, infectious diseases and cancers. Thus PCR is a revolutionary method which is capable of greatly stimulating scientific research and modifying the diagnostic area in the near future.
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44
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Kudo M, Ogura T, Esumi H, Sugimura T. Mutational activation of c-Ha-ras gene in squamous cell carcinomas of rat Zymbal gland induced by carcinogenic heterocyclic amines. Mol Carcinog 1991; 4:36-42. [PMID: 2009133 DOI: 10.1002/mc.2940040107] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The activation of the c-Ha-ras gene and its carcinogen specificity were examined in squamous cell carcinomas (SCCs) induced by the mutagenic heterocyclic amines 2-amino-3-methylimidazo [4,5-f]quinoline (IQ),2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) in the Zymbal gland in rats. DNA fragments of the c-Ha-ras gene were amplified from formalin-fixed and paraffin-embedded tissues by polymerase chain reaction and analyzed for activating mutations involving codons 12, 13, and 61 by oligonucleotide differential hybridization and sequencing. c-Ha-ras mutations were found in four of seven and two of six Zymbal gland SCCs induced by IQ and MeIQx, respectively. These mutations were located in either codon 13 or 61. In the case of MeIQ, point mutations at the second nucleotide of codon 13 were found in nine of the total 14 Zymbal gland SCCs and in one papilloma. Of the nine SCCs that had mutations in codon 13, two possessed mutations at the second nucleotide of codon 12 as well. Most reported mutations in c-Ha-ras are located at codon 12 or 61, but the heterocyclic amines in this study induced mutations not only at codons 12 and 61 but also in codon 13. Transversions were the dominant mutation induced by these heterocyclic amines.
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Affiliation(s)
- M Kudo
- Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan
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45
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Abstract
The tumour promoter okadaic acid is a potent and specific inhibitor of protein phosphatases 1 and 2A. Here we review recent studies which demonstrate that this toxin is extremely useful for identifying biological processes that are controlled through the reversible phosphorylation of proteins.
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Affiliation(s)
- P Cohen
- Department of Biochemistry, University of Dundee, UK
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46
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Abstract
Benzopyrene diol epoxide (BPDE; (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene), the ultimate carcinogen derived from the polycyclic hydrocarbon benzo[a]pyrene, reacts principally with the guanine bases in DNA. Nineteen double stranded, self-complementary oligonucleotides, containing deoxyguanosine in various sequence contexts, were each treated with tritium labelled BPDE. The extent of reaction was determined by releasing the BPDE-guanine adduct with acid, isolating it by chromatography on a reverse-phase column, and estimating it by its radioactivity. Oligonucleotides containing an isolated guanine, such as AAGTACTT, were little affected by BPDE. Reactivity was increased where the guanine was flanked by another guanine on the same strand (e.g. TACCTAGGTA) or on the complementary strand (e.g. TATTCGAATA), and was highest in mixed G-C sequences such as ATCCGGAT. The results should help predict major sites of attack of BPDE on cellular proto-oncogenes.
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Affiliation(s)
- M R Osborne
- Institute of Cancer Research, Chester Beatty Laboratory, London, U.K
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