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Nadel G, Yao Z, Hacohen-Lev-Ran A, Wainstein E, Maik-Rachline G, Ziv T, Naor Z, Admon A, Seger R. Phosphorylation of PP2Ac by PKC is a key regulatory step in the PP2A-switch-dependent AKT dephosphorylation that leads to apoptosis. Cell Commun Signal 2024; 22:154. [PMID: 38419089 PMCID: PMC10900696 DOI: 10.1186/s12964-024-01536-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 02/17/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Although GqPCR activation often leads to cell survival by activating the PI3K/AKT pathway, it was previously shown that in several cell types AKT activity is reduced and leads to JNK activation and apoptosis. The mechanism of AKT inactivation in these cells involves an IGBP1-coupled PP2Ac switch that induces the dephosphorylation and inactivation of both PI3K and AKT. However, the machinery involved in the initiation of PP2A switch is not known. METHODS We used phospho-mass spectrometry to identify the phosphorylation site of PP2Ac, and raised specific antibodies to follow the regulation of this phosphorylation. Other phosphorylations were monitored by commercial antibodies. In addition, we used coimmunoprecipitation and proximity ligation assays to follow protein-protein interactions. Apoptosis was detected by a TUNEL assay as well as PARP1 cleavage using SDS-PAGE and Western blotting. RESULTS We identified Ser24 as a phosphorylation site in PP2Ac. The phosphorylation is mediated mainly by classical PKCs (PKCα and PKCβ) but not by novel PKCs (PKCδ and PKCε). By replacing the phosphorylated residue with either unphosphorylatable or phosphomimetic residues (S24A and S24E), we found that this phosphorylation event is necessary and sufficient to mediate the PP2A switch, which ultimately induces AKT inactivation, and a robust JNK-dependent apoptosis. CONCLUSION Our results show that the PP2A switch is induced by PKC-mediated phosphorylation of Ser24-PP2Ac and that this phosphorylation leads to apoptosis upon GqPCR induction of various cells. We propose that this mechanism may provide an unexpected way to treat some cancer types or problems in the endocrine machinery.
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Affiliation(s)
- Guy Nadel
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Zhong Yao
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Avital Hacohen-Lev-Ran
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Ehud Wainstein
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Galia Maik-Rachline
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Ziv
- Smoler Proteomic Center, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zvi Naor
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Arie Admon
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rony Seger
- Department of Immunology and Regenerative Biology, the Weizmann Institute of Science, Rehovot, Israel.
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2
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Guo LC, Lv Z, Zhu T, He G, Hu J, Xiao J, Liu T, Yu S, Zhang J, Zhang H, Ma W. Associations between serum polychlorinated biphenyls, halogen flame retardants, and renal function indexes in residents of an e-waste recycling area. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159746. [PMID: 36306844 DOI: 10.1016/j.scitotenv.2022.159746] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 10/22/2022] [Accepted: 10/22/2022] [Indexed: 06/16/2023]
Abstract
E-waste handling activities release large quantities of polychlorinated biphenyls (PCBs) and halogen flame retardants (HFRs) into the surrounding area, creating a high exposure risk for local residents. However, the possibility of PCBs and HFRs exposure contributing to renal injury has not been extensively studied. To fill this knowledge gap, we conducted an epidemiological analysis of adolescents and adults recruited from an e-waste recycling area and a control area. Some PCBs and HFRs compounds were statistically significantly associated with the levels of β2-microglobulin (β2-MG), blood urea nitrogen (BUN), serum creatinine (SCr), and uric acid, with thyroid hormone-related genes found to partly mediate these associations. The interactions of PCBs and HFRs with metals also influenced renal function indexes. Exposure to high concentrations of PCBs and HFRs resulted in higher levels of β2-MG and lower levels of BUN and SCr in the exposed group. As indicated by the elevated β2-MG levels, high exposure to PCBs and HFRs may increase the risk of early renal injury for adolescents. These findings help to clarify the impacts of PCBs and HFRs on renal function and highlight the need to protect the health of residents in regions impacted by e-waste handling activities.
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Affiliation(s)
- Ling-Chuan Guo
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Zhanlu Lv
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Tingting Zhu
- State Environmental Protection Key Laboratory of Drinking Water Source Management and Technology, Shenzhen Key Laboratory of Emerging Contaminants Detection and Control in Water Environment, Guangdong Engineering Research Center of Low Energy Sewage Treatment, Shenzhen Academy of Environmental Sciences, Shenzhen 518001, China
| | - Guanhao He
- School of Medicine, Jinan University, Guangzhou 510632, China
| | - Jianxiong Hu
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Jianpeng Xiao
- Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Tao Liu
- School of Medicine, Jinan University, Guangzhou 510632, China
| | - Shengbing Yu
- Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
| | - Jinliang Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Han Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Wenjun Ma
- School of Medicine, Jinan University, Guangzhou 510632, China.
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3
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Black JD, Affandi T, Black AR, Reyland ME. PKCα and PKCδ: Friends and Rivals. J Biol Chem 2022; 298:102194. [PMID: 35760100 PMCID: PMC9352922 DOI: 10.1016/j.jbc.2022.102194] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/13/2022] [Accepted: 06/21/2022] [Indexed: 01/06/2023] Open
Abstract
PKC comprises a large family of serine/threonine kinases that share a requirement for allosteric activation by lipids. While PKC isoforms have significant homology, functional divergence is evident among subfamilies and between individual PKC isoforms within a subfamily. Here, we highlight these differences by comparing the regulation and function of representative PKC isoforms from the conventional (PKCα) and novel (PKCδ) subfamilies. We discuss how unique structural features of PKCα and PKCδ underlie differences in activation and highlight the similar, divergent, and even opposing biological functions of these kinases. We also consider how PKCα and PKCδ can contribute to pathophysiological conditions and discuss challenges to targeting these kinases therapeutically.
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Affiliation(s)
- Jennifer D Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE.
| | - Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus
| | - Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus.
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4
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Black AR, Black JD. The complexities of PKCα signaling in cancer. Adv Biol Regul 2021; 80:100769. [PMID: 33307285 PMCID: PMC8141086 DOI: 10.1016/j.jbior.2020.100769] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/15/2020] [Indexed: 01/06/2023]
Abstract
Protein kinase C α (PKCα) is a ubiquitously expressed member of the PKC family of serine/threonine kinases with diverse functions in normal and neoplastic cells. Early studies identified anti-proliferative and differentiation-inducing functions for PKCα in some normal tissues (e.g., regenerating epithelia) and pro-proliferative effects in others (e.g., cells of the hematopoietic system, smooth muscle cells). Additional well documented roles of PKCα signaling in normal cells include regulation of the cytoskeleton, cell adhesion, and cell migration, and PKCα can function as a survival factor in many contexts. While a majority of tumors lose expression of PKCα, others display aberrant overexpression of the enzyme. Cancer-related mutations in PKCα are uncommon, but rare examples of driver mutations have been detected in certain cancer types (e. g., choroid gliomas). Here we review the role of PKCα in various cancers, describe mechanisms by which PKCα affects cancer-related cell functions, and discuss how the diverse functions of PKCα contribute to tumor suppressive and tumor promoting activities of the enzyme. We end the discussion by addressing mutations and expression of PKCα in tumors and the clinical relevance of these findings.
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Affiliation(s)
- Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jennifer D Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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5
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Ha M, Huang X, Li L, Lu D, Liu C. PKCα mediated by the PI3K/Akt-FOXA1 cascade facilitates cypermethrin-induced hyperthyroidism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143727. [PMID: 33250241 DOI: 10.1016/j.scitotenv.2020.143727] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/14/2020] [Accepted: 10/31/2020] [Indexed: 06/12/2023]
Abstract
Cypermethrin (CYP), a broad-spectrum pyrethroid insecticide is extensively used. CYP is also considered as a potential endocrine disruptor with the thyroid-disturbing property. Protein kinase C alpha (PKCα) is a pleiotropic signal transduction molecule that functions crucially in thyroid hormone (TH) homeostasis and thyroid functions. To explore underlying roles of PKCα in CYP-mediated disturbance of TH homeostasis, Sprague-Dawley rats and rat thyroid cells were used in this study. Results showed that β-CYP stimulated TH biosynthesis, as shown by the increase in plasma levels of TT4, FT4, TT3, FT3, and TSH. After β-CYP treatment, expressions of PKCα, three miRNAs (miR-17-5p, miR-330-3p, and miR-331-3p), thyroid transcription factor TTF-1, and thyroid-specific proteins (TSHr, TPO, and Tg) were significantly increased, while expressions of PI3K p110α, p-Akt, FOXA1, and thyroid transcription factors (TTF-2 and Pax8) were decreased. Further studies found that β-CYP induced PKCα translation by the miR-330-3p-targeted PI3K/Akt-FOXA1 cascade and then PKCα positively regulated TTF-1 to promote TPO and Tg expressions, which in turn facilitated TH biosynthesis. Likewise, PKCα positively modulated TSHr expressions to strengthen the TSH/TSHr signal in the HPT axis, thereby synergistically contributing to TH biosynthesis. Moreover, β-CYP also disturbed TH biotransformation and biotransport by inducing DIO1 and inhibiting DIO3 in thyroids and TTR expressions in livers. Taken together, β-CYP has the thyroid-disturbing effect and could promote TH biosynthesis, and PKCα plays vital roles in β-CYP-caused hyperthyroidism.
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Affiliation(s)
- Mei Ha
- School of Nursing, Chongqing Medical and Pharmaceutical College, Chongqing 400020, China
| | - Xu Huang
- NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, China
| | - Lianbing Li
- NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, China
| | - Daru Lu
- NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, China
| | - Changjiang Liu
- NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning Science and Technology Research Institute, Chongqing 400020, China.
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6
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Rahman MS, Thomas P. Interactive effects of hypoxia and PCB co-exposure on expression of CYP1A and its potential regulators in Atlantic croaker liver. ENVIRONMENTAL TOXICOLOGY 2018; 33:411-421. [PMID: 29316220 DOI: 10.1002/tox.22527] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/12/2017] [Accepted: 12/26/2017] [Indexed: 06/07/2023]
Abstract
Although marine and coastal environments which are contaminated with xenobiotic organic compounds often become hypoxic during the summer, the interactive effects of hypoxia and xenobiotic exposure on marine species such as teleost fishes remain poorly understood. The expression and activity of monooxygenase enzyme cytochrome P450-1A (CYP1A) in fishes are upregulated by exposure to polychlorinated biphenyls (PCBs), whereas they are down-regulated during hypoxia exposure. We investigated the interactive effects of hypoxia and PCB co-exposure on hepatic CYP1A expression in Atlantic croaker and on potential regulators of CYP1A. Croaker were exposed to hypoxia (1.7 mg/L dissolved oxygen), 3,3',4,4'-tetrachlorobiphenyl (PCB 77, dose: 2 and 8 µg/g body weight), and Aroclor 1254 (a common PCB mixture, dose: 0.5 and 1 µg/g body weight), alone and in combination for 4 weeks. PCB 77 exposure markedly increased hepatic CYP1A mRNA and protein expression, and ethoxyresorufin-O-deethylase (EROD, an indicator of CYP1A enzyme) activity and increased endothelial nitric oxide synthase (eNOS) protein expression. PCB 77 treatment also increased interleukin-1β (IL-1β, a cytokine) mRNA levels and protein carbonyl (PC, an indicator of reactive oxygen species, ROS) contents. These marked PCB 77- and Aroclor 1254-induced increases in CYP1A mRNA levels and EROD activity were significantly attenuated by co-exposure to hypoxia, whereas the increases in hepatic eNOS protein and IL-1β mRNA expression, and PC contents were augmented by hypoxia co-exposure. The results suggest that biotransformation of organic xenobiotics by CYP1A is reduced in fish during co-exposure to hypoxia and is accompanied by alterations in eNOS, ROS, and IL-1β levels.
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Affiliation(s)
- Md Saydur Rahman
- School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, Texas, 78520
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, 78373
| | - Peter Thomas
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, 78373
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7
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Long-term in vivo polychlorinated biphenyl 126 exposure induces oxidative stress and alters proteomic profile on islets of Langerhans. Sci Rep 2016; 6:27882. [PMID: 27292372 PMCID: PMC4904407 DOI: 10.1038/srep27882] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/24/2016] [Indexed: 12/15/2022] Open
Abstract
It has been recently proposed that exposure to polychlorinated biphenyls (PCBs) is a risk factor to type 2 diabetes mellitus (DM2). We investigated this hypothesis using long-term in vivo PCB126 exposure to rats addressing metabolic, cellular and proteomic parameters. Male Wistar rats were exposed to PCB126 (0.1, 1 or 10 μg/kg of body weight/day; for 15 days) or vehicle by intranasal instillation. Systemic alterations were quantified by body weight, insulin and glucose tolerance, and blood biochemical profile. Pancreatic toxicity was measured by inflammatory parameters, cell viability and cycle, free radical generation, and proteomic profile on islets of Langerhans. In vivo PCB126 exposure enhanced the body weight gain, impaired insulin sensitivity, reduced adipose tissue deposit, and elevated serum triglycerides, cholesterol, and insulin levels. Inflammatory parameters in the pancreas and cell morphology, viability and cycle were not altered in islets of Langerhans. Nevertheless, in vivo PCB126 exposure increased free radical generation and modified the expression of proteins related to oxidative stress on islets of Langerhans, which are indicative of early β-cell failure. Data herein obtained show that long-term in vivo PCB126 exposure through intranasal route induced alterations on islets of Langerhans related to early end points of DM2.
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8
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Murati T, Šimić B, Brozovic A, Kniewald J, Miletić Gospić A, Bilandžić N, Kmetič I. PCB 77 action in ovary cells--toxic effects, apoptosis induction and cell cycle analysis. Toxicol Mech Methods 2015; 25:302-11. [PMID: 25835094 DOI: 10.3109/15376516.2015.1028605] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT PCB 77 (3,3',4,4'-tetrachlorobiphenyl), a non-ortho congener with planar configuration, has been identified as potential endocrine disrupter capable to increase the risk of reproductive and developmental failure. OBJECTIVE In the present study, in vitro PCB 77 toxic potential, apoptosis induction and cell cycle alterations were investigated to reveal direct toxic effects on ovarian cells. METHODS Chinese Hamster Ovary (CHO-K1) cell line was selected as a model system and decreased cell viability was confirmed by application of four bioassays. Cellular morphology and quantitative analysis of apoptotic, necrotic and viable cells were determined with fluorescent microscopy and cell cycle phase distributions by measuring DNA content using flow cytometry. RESULTS We have indicated Trypan blue exclusion assay as the most sensitive for quantifying cytotoxicity of PCB 77 in terms of IC50 values, while the results obtained by other methods pointed to a possible localized effect on the lysosomes/endosomes (Neutral red), compromised intracellular metabolic processes (MTT) and possible interferation with the rate of protein synthesis (Kenacid blue). The loss of cell viability, as a consequence of treatment with 10-100 μM PCB 77, fundamentally was due to induction of apoptosis with observed common series of specific morphological changes characteristic to apoptotic phenomenon. The level of alterations of normal cell cycle progression was low without significant changes at analyzed time intervals. CONCLUSION These results indicate toxic outcomes of PCB 77 at ovarian cellular level with regard to potential direct adverse effects to female reproductive system.
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Affiliation(s)
- Teuta Murati
- a Laboratory for Toxicology, Faculty of Food Technology and Biotechnology , University of Zagreb , Zagreb , Croatia
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9
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Abella V, Santoro A, Scotece M, Conde J, López-López V, Lazzaro V, Gómez-Reino JJ, Meli R, Gualillo O. Non-dioxin-like polychlorinated biphenyls (PCB 101, PCB 153 and PCB 180) induce chondrocyte cell death through multiple pathways. Toxicol Lett 2015; 234:13-9. [DOI: 10.1016/j.toxlet.2015.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 01/08/2023]
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10
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Su K, Lv X, Song H, Luo X, Chen C. PCB77 Inducing Renal Tubular Cell Apoptosis. Ultrastruct Pathol 2014; 39:192-7. [DOI: 10.3109/01913123.2014.973130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Hamra GB, MacLehose R, Richardson D, Bertke S, Daniels RD. Modelling complex mixtures in epidemiologic analysis: additive versus relative measures for differential effectiveness. Occup Environ Med 2013; 71:141-6. [DOI: 10.1136/oemed-2013-101665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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12
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Hamra G, Richardson D, Maclehose R, Wing S. Integrating informative priors from experimental research with Bayesian methods: an example from radiation epidemiology. Epidemiology 2013; 24:90-5. [PMID: 23222512 DOI: 10.1097/ede.0b013e31827623ea] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Informative priors can be a useful tool for epidemiologists to handle problems of sparse data in regression modeling. It is sometimes the case that an investigator is studying a population exposed to two agents, X and Y, where Y is the agent of primary interest. Previous research may suggest that the exposures have different effects on the health outcome of interest, one being more harmful than the other. Such information may be derived from epidemiologic analyses; however, in the case where such evidence is unavailable, knowledge can be drawn from toxicologic studies or other experimental research. Unfortunately, using toxicologic findings to develop informative priors in epidemiologic analyses requires strong assumptions, with no established method for its utilization. We present a method to help bridge the gap between animal and cellular studies and epidemiologic research by specification of an order-constrained prior. We illustrate this approach using an example from radiation epidemiology.
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Affiliation(s)
- Ghassan Hamra
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435, USA.
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13
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Zhang HM, Lin N, Dong Y, Su Q, Luo M. Protein kinase Cα is involved in impaired perinatal hypothyroid rat brain development. J Neurosci Res 2012; 91:211-9. [PMID: 23152155 DOI: 10.1002/jnr.23125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 06/28/2012] [Accepted: 07/13/2012] [Indexed: 11/07/2022]
Abstract
Protein kinase Cα (PKCα) has been implicated in the regulation of a variety of cellular functions, such as proliferation, differentiation, and apoptosis, in response to a diverse range of stimuli. Activated PKCα mediates oxidative stress, apoptosis, and inflammatory reaction. Thyroid hormone (TH) is essential for the proper development of the mammalian central nervous system. TH deficiency during critical periods of brain development results in permanent cognitive and neurological impairments. In the present study, we attempted to explore whether PKCα is involved in impaired brain function in developing hypothyroid rat brain. Severe perinatal hypothyroidism was obtained by administration of 30 mg/day propylthiouracil to dams. Brain PKC activity in hypothyroid pups was increased significantly in cytosol and membrane fractions. The change of membrane PKC activity was more marked than that of cytosol, and hypothyroidism led to a higher ratio of membrane PKC activity to that in cytosol, which means abnormal activation of PKC in developing hypothyroid rat brain. Thyroxine replacement partially corrected these changes. After being treated with bisindolmaleimide XI, a mainly selective inhibitor for PKCα, the hypothyroid pups showed improved place navigation test results, and further Western blot analysis showed that PKCα expression in cytosol fractions was increased in hypothyroid rat brain with or without bisindolmaleimide XI treatment, but, after treatment with bisindolmaleimide XI, PKCα content in membrane fractions decreased almost to normal. Therefore, we conclude that PKCα appears to be involved in the impaired brain development observed in perinatal hypothyroid rat brain.
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Affiliation(s)
- Hong-Mei Zhang
- Department of Endocrinology, Xin Hua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
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14
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Shen K, Shen C, Chen L, Chen X, Chen Y. Morphological alterations of Vero cell exposed to coplanar PCB 126 and noncoplanar PCB 153. ENVIRONMENTAL TOXICOLOGY 2012; 27:26-31. [PMID: 20549637 DOI: 10.1002/tox.20608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 03/08/2010] [Accepted: 03/13/2010] [Indexed: 05/29/2023]
Abstract
Polychlorinated biphenyls (PCBs) are widespread, persistent environmental contaminants that display a complex spectrum of toxicological properties. Exposure to PCBs has been associated with morphological anomalies in cell cultures. However, most mechanistic studies of PCBs' toxic activity have been focused on coplanar congeners. It is of importance to determine whether PCB treatment would influence cell configuration and whether these changes would depend on the structural characteristics of PCBs. In this study, we investigated cell morphological alteration in Vero cell cultures after exposure to coplanar PCB 126 and noncoplanar PCB 153. The survival of Vero cells was measured through the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test. Cytotoxicity results suggested that PCB congeners had a toxic, antiproliferative effect on Vero cells. Morphological studies described structural modifications and provided evidence that apoptosis might be the main cell death pathway in PCB 153-treated cells. The comparison between PCB 126 and PCB 153 indicated that the cell death mechanisms involved in coplanar or noncoplanar PCB congener exposure were different in Vero cells.
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Affiliation(s)
- Kaili Shen
- Institute of Environmental Science and Technology, Zhejiang University, Hangzhou, China
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15
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Ferrante M, Mattace Raso G, Esposito E, Bianco G, Iacono A, Clausi M, Amero P, Santoro A, Simeoli R, Autore G, Meli R. Effects of non-dioxin-like polychlorinated biphenyl congeners (PCB 101, PCB 153 and PCB 180) alone or mixed on J774A.1 macrophage cell line: modification of apoptotic pathway. Toxicol Lett 2011; 202:61-8. [DOI: 10.1016/j.toxlet.2011.01.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/21/2011] [Accepted: 01/25/2011] [Indexed: 11/28/2022]
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16
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Franco R, Sánchez-Olea R, Reyes-Reyes EM, Panayiotidis MI. Environmental toxicity, oxidative stress and apoptosis: ménage à trois. Mutat Res 2008; 674:3-22. [PMID: 19114126 DOI: 10.1016/j.mrgentox.2008.11.012] [Citation(s) in RCA: 350] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 11/27/2008] [Indexed: 12/21/2022]
Abstract
Apoptosis is an evolutionary conserved homeostatic process involved in distinct physiological processes including organ and tissue morphogenesis, development and senescence. Its deregulation is also known to participate in the etiology of several human diseases including cancer, neurodegenerative and autoimmune disorders. Environmental stressors (cytotoxic agents, pollutants or toxicants) are well known to induce apoptotic cell death and to contribute to a variety of pathological conditions. Oxidative stress seems to be the central element in the regulation of the apoptotic pathways triggered by environmental stressors. In this work, we review the established mechanisms by which oxidative stress and environmental stressors regulate the apoptotic machinery with the aim to underscore the relevance of apoptosis as a component in environmental toxicity and human disease progression.
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Affiliation(s)
- Rodrigo Franco
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, P. O. Box 12233, 111. T.W. Alexander Drive, Research Triangle Park, NC 27709, United States.
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17
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Different effects of PCB101, PCB118, PCB138 and PCB153 alone or mixed in MCF-7 breast cancer cells. Food Chem Toxicol 2008; 46:2561-7. [DOI: 10.1016/j.fct.2008.04.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 11/20/2022]
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Dutta SK, Ghosh S, De S, Hoffman EP. CYP1A1 and MT1K are congener specific biomarker genes for liver diseases induced by PCBs. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2008; 25:218-221. [PMID: 21783860 DOI: 10.1016/j.etap.2007.10.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have identified two most significant biomarker genes, CYP1A1 (69.81 up-regulation) and MT1K (14.66 up-regulation), showing highest overexpression at p-value <0.005. These were selected out of several hundred genes induced in vitro, using PCB exposed human liver (HepG2) cells. Over expression of the CYP1A1 (cytochrome P450) gene was specific to PCB-77 and MT1K (Metallothionein) to PCB-153. Affymetrix oligonucleotide microarrays (mRNA) were used to screen the entire genome of human liver cells in a time-dependent exposure and were further validated by quantitative real-time RT-PCR.
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Affiliation(s)
- Sisir K Dutta
- Molecular Genetics Laboratory, Department of Biology, Howard University, 415 College Street, NW, Washington DC 20059, USA
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Ghosh S, De S, Dutta SK. Altered protein expressions in chronic PCB-153-induced human liver (HepG2) cells. Int J Toxicol 2007; 26:203-12. [PMID: 17564901 DOI: 10.1080/10915810701352648] [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] [Indexed: 01/08/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a group of persistent and widely distributed environmental pollutants that have various deleterious effects, e.g., neurotoxic, endocrine disruption and reproductive abnormalities, including cancers. Chronic exposure to environmentally hazardous chemicals like PCBs is of great concern to human health. It has been reported earlier that apoptotic proteins change in rats under chronic PCB treatment. It is of importance to determine if chronically exposed human cells develop a different protein expression. In the present study, the authors chronically exposed metabolically competent human liver (HepG2) cells at 50 to 100 microM to examine the role of the well-known environmentally hazardous pollutant non-coplanar 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) to study cell death. After 12 weeks of exposure these cells showed significant changes in apoptotic death in subsequent trypan blue growth assay, fluorescence microscopy, DNA fragmentation, and immunoblotting studies. Interestingly, chronically exposed cells showed marked differences in apoptotic and/or death-related proteins (e.g., Bcl2, Bak, and the pro and active forms of caspase-9, which were up-regulated), in contrast to acutely exposed (i.e., 48-h PCB-153 exposed) cells, which maintained linear growth despite repeated exposures. Similarly, tumor suppressor protein p53, proto-oncogene c-myc, and cell cycle regulator protein p21 were also up-regulated compared to nonchronically exposed HepG2 Cells. The results indicated that PCB-153-induced chronic exposure significantly altered different apoptotic (e.g., Bcl2, Bak, caspase-3) and tumor suppressor (e.g., p21, p53, and c-myc) proteins in the cellular model. These results suggest that chronic exposure to PCB-153 can induce cell survival by altering several apoptotic and tumor suppressor proteins.
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Hou RR, Chen JZ, Chen H, Kang XG, Li MG, Wang BR. Neuroprotective effects of (-)-epigallocatechin-3-gallate (EGCG) on paraquat-induced apoptosis in PC12 cells. Cell Biol Int 2007; 32:22-30. [PMID: 17936647 DOI: 10.1016/j.cellbi.2007.08.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 04/15/2007] [Accepted: 08/21/2007] [Indexed: 01/01/2023]
Abstract
Green tea, owing to its beneficial effect on health, is becoming more and more popular worldwide. (-)-Epigallocatechin-3-gallate (EGCG), the main ingredient of green tea polyphenols, is a known protective effect on injured neurons in neurodegenerative disease, such as Alzheimer's disease and Parkinson's disease. Paraquat (PQ) is a widely used herbicide that possesses a similar structure to MPP(+) and is toxic to mesencephalic dopaminergic neurons. In the present study, PQ-injured PC12 cells were chosen as an in vitro cell model of Parkinson's disease and the neuroprotective effects of EGCG were investigated. The results showed that EGCG attenuated apoptosis of PC12 cells induced by PQ. The possible mechanism may be associated with maintaining mitochondrial membrane potential, inhibiting caspase-3 activity and downregulating the expression of pro-apoptotic protein Smac in cytosol. The present study supports the notion that EGCG could be used as a neuroprotective agent for treatment of neurodegenerative diseases.
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Affiliation(s)
- Rong-Rong Hou
- Laboratory of Integrated Traditional Chinese Medicine and Western Medicine on Elderly Encephalopathy, Research Center of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, 710032 Xi'an, Shaanxi, China
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21
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Menzel R, Yeo HL, Rienau S, Li S, Steinberg CEW, Stürzenbaum SR. Cytochrome P450s and short-chain dehydrogenases mediate the toxicogenomic response of PCB52 in the nematode Caenorhabditis elegans. J Mol Biol 2007; 370:1-13. [PMID: 17499272 DOI: 10.1016/j.jmb.2007.04.058] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 04/13/2007] [Accepted: 04/19/2007] [Indexed: 11/28/2022]
Abstract
Although non-coplanar PCBs are ubiquitous organic chemicals known to induce numerous biological responses and thus are toxic to man and wildlife, little is known about the toxic mode of action. Using PCB52, an ortho-substituted, 2,2',5,5'-tetrachlorobiphenyl, it was possible to pinpoint the relationship between induced gene expression and observed toxicity in the model nematode Caenorhabditis elegans. On the basis of the calculated EC20 for brood size (5 mg/l), whole genome DNA microarray experiments were performed to identify differentially expressed genes. Gene knockdown by RNAi was used to determine the consequences in reproductive fitness in the presence and in the absence of PCB52. On the basis of altered phenotype, several gene classes were identified to have a pivotal role in PCB52 toxicogenesis, most notably cytochrome P450s, short-chain dehydrogenases and lipases. In addition to this, four of six selected cytochrome P450s were shown to be involved in fat storage, with PCB52 exposure increasing the fat content in N2 wild-type as indicated by staining with Nile red. Furthermore, exposure to PCB52 induces a general detoxification response via small heat-shock proteins and caspases. Our data provide strong evidence of the molecular mechanisms that underlie the toxicity of non-coplanar PCBs, and confirms that, despite the ability to metabolize PCB, alterations in lipid metabolism and storage are major factors that drive the toxic effect of PCB52.
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Affiliation(s)
- Ralph Menzel
- Department of Biology, Freshwater and Stress Ecology, Humboldt University at Berlin, Unter den Linden 6, 10099 Berlin, Germany
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Huang J, Wang Y, Guo J, Lu H, Lin X, Ma L, Teitz-Tennenbaum S, Chang AE, Li Q. Radiation-induced apoptosis along with local and systemic cytokine elaboration is associated with DC plus radiotherapy-mediated renal cell tumor regression. Clin Immunol 2007; 123:298-310. [PMID: 17449328 DOI: 10.1016/j.clim.2007.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 02/14/2007] [Accepted: 02/16/2007] [Indexed: 02/07/2023]
Abstract
Utilizing melanoma and sarcoma tumor models syngeneic to C57BL/6 mice, we previously reported the antitumor effects of intratumoral (i.t.) administration of dendritic cells (DC) combined with localized radiotherapy (RT). However, the mechanisms underlying the augmented therapeutic effects have yet to be fully defined. Using the BALB/c host, we explored in this study the capacity of RT to augment the therapeutic efficacy of DC in the syngeneic renal cell cancer, Renca. I.t. DC administration combined with RT inhibited tumor growth in a synergistic manner. This extends our previous findings using a different host strain and two histologically distinct tumor models. More importantly, we provide evidence in this report that RT induced significant apoptosis and necrosis in Renca tumor cells, which involved down-regulated expression of Bcl-2 and a concurrent up-regulated expression of Bax. We also found significantly elevated expression of TNFalpha in RT plus DC-treated Renca tumors. Furthermore, splenocytes isolated from DC plus RT-treated mice elaborated higher levels of IL-2, IL-4, IFNgamma and IgG, IgM in response to tumor cells compared with splenocytes from monotherapy-treated hosts. These data support the conclusion that radiotherapy enhanced DC vaccination by inducing tumor cell apoptosis in BABL/c host, and the significantly augmented therapeutic efficacy by RT+DC treatment was associated with an increased local production of TNFalpha as well as an amplified systemic antitumor responses conferred by the combined therapy. I.t. DC administration in concert with localized RT may represent a promising novel regimen for human cancer therapy.
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Affiliation(s)
- Jianhua Huang
- Department of Immunology, The PLA General Hospital, Beijing, China, and Division of Surgical Oncology, University of Michigan, Ann Arbor 48109-0666, USA
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23
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Santiago MF, López-Aparicio P, Recio MN, Pérez-Albarsanz MA. Effect of aroclor 1248 and two pure PCB congeners on phospholipase D activity in rat renal tubular cell cultures. J Biochem Mol Toxicol 2007; 21:68-75. [PMID: 17427178 DOI: 10.1002/jbt.20160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This paper elucidates the effect of different polychlorinated biphenyls (PCBs) on the phospholipase D (PLD) activity in soluble and particulate fractions of rat renal proximal tubular culture cells. Treatment with Aroclor 1248 (a commercial PCB mixture) caused a marked increase in the activity of PLD in intact renal tubular cells. The PLD activity was increased by Aroclor 1248 in the particulate fraction while the enzyme activity was unaffected in the soluble fraction. This work also shows that PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl, a di-ortho-substituted nonplanar congener) can increase the activity of PLD only in the particulate fraction. The exposure of cell cultures to PCB 77 (3,3',4,4'-tetrachlorobiphenyl, a non-ortho-substituted planar congener) does not alter PLD activity. These results suggest that PCB effects are structure dependent. Therefore, in order to clarify the molecular mechanism of activation of PLD by PCBs, the contents of immunoreactive PLD were examined by immunoblot analysis. Renal tubular cells expressed a PLD protein of 120 kDa corresponding with the PLD1 mammalian isoform in both the particulate and the soluble fraction. Aroclor 1248, PCB 153, and PCB 77 do not induce changes in the levels of PLD protein. These data indicate that PCBs, particularly nonplanar congeners, increase PLD activity. Moreover, these changes could not be demonstrated in the enzyme content in rat renal tubular cell cultures.
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Affiliation(s)
- Mercedes Fernández Santiago
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
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Weiland C, Ahr HJ, Vohr HW, Ellinger-Ziegelbauer H. Characterization of primary rat proximal tubular cells by gene expression analysis. Toxicol In Vitro 2006; 21:466-91. [PMID: 17134868 DOI: 10.1016/j.tiv.2006.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 09/27/2006] [Accepted: 10/15/2006] [Indexed: 11/29/2022]
Abstract
The kidney plays a major role in excretory and reabsorptive processes. The kidney cortex consists primarily of proximal tubular cells, which are epithelial cells that are often involved in the induction and progression of various kidney diseases. Therefore primary proximal tubular cells are widely used as a renal cell model. To further characterize this kidney in vitro model different time points in culture after isolation of the cells were compared to the cortex in vivo using gene expression analysis based on microarrays. This study revealed that many metabolic pathways and some kidney-specific functions are lacking in the in vitro model. Furthermore genes involved in RNA and protein synthesis, intracellular transport, extracellular matrix and cytoskeletal organization were upregulated in culture compared to in vivo, indicating proliferation of the cells and differentiation into a cell culture phenotype. The data represented here may help to evaluate the in vivo relevance of results obtained with this in vitro model.
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Affiliation(s)
- C Weiland
- Molecular and Special Toxicology, Bayer HealthCare AG, Aprather Weg 18a, D-42096 Wuppertal, Germany.
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