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Martins DJ, Singh JK, Jahjah T, Vessoni AT, Leandro GDS, Silva MM, Biard DSF, Quinet A, Menck CFM. Polymerase iota plays a key role during translesion synthesis of UV-induced lesions in the absence of polymerase eta. Photochem Photobiol 2024; 100:4-18. [PMID: 37926965 DOI: 10.1111/php.13879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/29/2023] [Accepted: 10/18/2023] [Indexed: 11/07/2023]
Abstract
Xeroderma pigmentosum (XP) variant cells are deficient in the translesion synthesis (TLS) DNA polymerase Polη (eta). This protein contributes to DNA damage tolerance, bypassing unrepaired UV photoproducts and allowing S-phase progression with minimal delay. In the absence of Polη, backup polymerases perform TLS of UV lesions. However, which polymerase plays this role in human cells remains an open question. Here, we investigated the potential role of Polι (iota) in bypassing ultraviolet (UV) induced photoproducts in the absence of Polη, using NER-deficient (XP-C) cells knocked down for Polι and/or Polη genes. Our results indicate that cells lacking either Polι or Polη have increased sensitivity to UVC radiation. The lack of both TLS polymerases led to increased cell death and defects in proliferation and migration. Loss of both polymerases induces a significant replication fork arrest and G1/S-phase blockage, compared to the lack of Polη alone. In conclusion, we propose that Polι acts as a bona fide backup for Polη in the TLS of UV-photoproducts.
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Affiliation(s)
- Davi Jardim Martins
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
| | - Jenny Kaur Singh
- Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
| | - Tiya Jahjah
- Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
| | - Alexandre Teixeira Vessoni
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
- Sanofi R&D, Vitry-sur-Seine, France
| | - Giovana da Silva Leandro
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
| | - Matheus Molina Silva
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
| | - Denis Serge François Biard
- Université Paris-Saclay, Institut de Biologie François Jacob, Service d'étude des prions et maladies atypiques, iRCM/IBJF, Fontenay-aux-Roses, France
| | - Annabel Quinet
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Sao Paulo, Brazil
- Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
- Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRS/iRCM/IBFJ, Fontenay-aux-Roses, France
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Munroe M, Niero EL, Fok WC, Vessoni AT, Jeong H, Brenner KA, Batista LFZ. Telomere Dysfunction Activates p53 and Represses HNF4α Expression Leading to Impaired Human Hepatocyte Development and Function. Hepatology 2020; 72:1412-1429. [PMID: 32516515 PMCID: PMC7693115 DOI: 10.1002/hep.31414] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/04/2020] [Accepted: 05/19/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND AIMS Telomere attrition is a major risk factor for end-stage liver disease. Due to a lack of adequate models and intrinsic difficulties in studying telomerase in physiologically relevant cells, the molecular mechanisms responsible for liver disease in patients with telomere syndromes remain elusive. To circumvent that, we used genome editing to generate isogenic human embryonic stem cells (hESCs) harboring clinically relevant mutations in telomerase and subjected them to an in vitro, stage-specific hepatocyte differentiation protocol that resembles hepatocyte development in vivo. APPROACH AND RESULTS Using this platform, we observed that while telomerase is highly expressed in hESCs, it is quickly silenced, specifically due to telomerase reverse transcriptase component (TERT) down-regulation, immediately after endoderm differentiation and completely absent in in vitro-derived hepatocytes, similar to what is observed in human primary hepatocytes. While endoderm derivation is not impacted by telomere shortening, progressive telomere dysfunction impaired hepatic endoderm formation. Consequently, hepatocyte derivation, as measured by expression of specific hepatic markers as well by albumin expression and secretion, is severely compromised in telomerase mutant cells with short telomeres. Interestingly, this phenotype was not caused by cell death induction or senescence. Rather, telomere shortening prevents the up-regulation and activation of human hepatocyte nuclear factor 4 alpha (HNF4α) in a p53-dependent manner. Both reactivation of telomerase and silencing of p53 rescued hepatocyte formation in telomerase mutants. Likewise, the conditional expression (doxycycline-controlled) of HNF4α, even in cells that retained short telomeres, accrued DNA damage, and exhibited p53 stabilization, successfully restored hepatocyte formation from hESCS. CONCLUSIONS Our data show that telomere dysfunction acts as a major regulator of HNF4α during hepatocyte development, pointing to a target in the treatment of liver disease in telomere-syndrome patients.
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Affiliation(s)
- Michael Munroe
- Department of MedicineWashington University in St. LouisSt. LouisMO
| | | | - Wilson Chun Fok
- Department of MedicineWashington University in St. LouisSt. LouisMO
| | | | - Ho‐Chang Jeong
- Department of MedicineWashington University in St. LouisSt. LouisMO
| | - Kirsten Ann Brenner
- Department of MedicineWashington University in St. LouisSt. LouisMO
- Present address:
Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMI
| | - Luis Francisco Zirnberger Batista
- Department of MedicineWashington University in St. LouisSt. LouisMO
- Department of Developmental BiologyWashington University in St. LouisSt. LouisMO
- Center of Regenerative MedicineWashington University in St. LouisSt. LouisMO
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Vessoni AT, Guerra CCC, Kajitani GS, Nascimento LLS, Garcia CCM. Cockayne Syndrome: The many challenges and approaches to understand a multifaceted disease. Genet Mol Biol 2020; 43:e20190085. [PMID: 32453336 PMCID: PMC7250278 DOI: 10.1590/1678-4685-gmb-2019-0085] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 01/15/2020] [Indexed: 01/04/2023] Open
Abstract
The striking and complex phenotype of Cockayne syndrome (CS) patients combines progeria-like features with developmental deficits. Since the establishment of the in vitro culture of skin fibroblasts derived from patients with CS in the 1970s, significant progress has been made in the understanding of the genetic alterations associated with the disease and their impact on molecular, cellular, and organismal functions. In this review, we provide a historic perspective on the research into CS by revisiting seminal papers in this field. We highlighted the great contributions of several researchers in the last decades, ranging from the cloning and characterization of CS genes to the molecular dissection of their roles in DNA repair, transcription, redox processes and metabolism control. We also provide a detailed description of all pathological mutations in genes ERCC6 and ERCC8 reported to date and their impact on CS-related proteins. Finally, we review the contributions (and limitations) of many genetic animal models to the study of CS and how cutting-edge technologies, such as cell reprogramming and state-of-the-art genome editing, are helping us to address unanswered questions.
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Affiliation(s)
| | - Camila Chaves Coelho Guerra
- Universidade Federal de Ouro Preto, Instituto de Ciências Exatas e
Biológicas, Núcleo de Pesquisa em Ciências Biológicas & Departamento de Ciências
Biológicas, Ouro Preto, MG, Brazil
| | - Gustavo Satoru Kajitani
- Universidade Federal de Ouro Preto, Instituto de Ciências Exatas e
Biológicas, Núcleo de Pesquisa em Ciências Biológicas & Departamento de Ciências
Biológicas, Ouro Preto, MG, Brazil
- Universidade de São Paulo, Instituto de Ciências Biomédicas,
Departamento de Microbiologia, São Paulo,SP, Brazil
| | - Livia Luz Souza Nascimento
- Universidade de São Paulo, Instituto de Ciências Biomédicas,
Departamento de Microbiologia, São Paulo,SP, Brazil
| | - Camila Carrião Machado Garcia
- Universidade Federal de Ouro Preto, Instituto de Ciências Exatas e
Biológicas, Núcleo de Pesquisa em Ciências Biológicas & Departamento de Ciências
Biológicas, Ouro Preto, MG, Brazil
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de Oliveira Alves N, Vessoni AT, Quinet A, Fortunato RS, Kajitani GS, Peixoto MS, Hacon SDS, Artaxo P, Saldiva P, Menck CFM, Batistuzzo de Medeiros SR. Biomass burning in the Amazon region causes DNA damage and cell death in human lung cells. Sci Rep 2017; 7:10937. [PMID: 28883446 PMCID: PMC5589902 DOI: 10.1038/s41598-017-11024-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/11/2017] [Indexed: 01/26/2023] Open
Abstract
Most of the studies on air pollution focus on emissions from fossil fuel burning in urban centers. However, approximately half of the world's population is exposed to air pollution caused by biomass burning emissions. In the Brazilian Amazon population, over 10 million people are directly exposed to high levels of pollutants resulting from deforestation and agricultural fires. This work is the first study to present an integrated view of the effects of inhalable particles present in emissions of biomass burning. Exposing human lung cells to particulate matter smaller than 10 µm (PM10), significantly increased the level of reactive oxygen species (ROS), inflammatory cytokines, autophagy, and DNA damage. Continued PM10 exposure activated apoptosis and necrosis. Interestingly, retene, a polycyclic aromatic hydrocarbon present in PM10, is a potential compound for the effects of PM10, causing DNA damage and cell death. The PM10 concentrations observed during Amazon biomass burning were sufficient to induce severe adverse effects in human lung cells. Our study provides new data that will help elucidate the mechanism of PM10-mediated lung cancer development. In addition, the results of this study support the establishment of new guidelines for human health protection in regions strongly impacted by biomass burning.
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Affiliation(s)
| | - Alexandre Teixeira Vessoni
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Medicine, Washington University in St. Louis, Saint Louis, Missouri, USA
| | - Annabel Quinet
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, USA
| | - Rodrigo Soares Fortunato
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gustavo Satoru Kajitani
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | | | | | - Paulo Artaxo
- Institute of Physics, University of São Paulo, São Paulo, Brazil
| | - Paulo Saldiva
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
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Quinet A, Martins DJ, Vessoni AT, Biard D, Sarasin A, Stary A, Menck CFM. Translesion synthesis mechanisms depend on the nature of DNA damage in UV-irradiated human cells. Nucleic Acids Res 2016; 44:5717-31. [PMID: 27095204 PMCID: PMC4937316 DOI: 10.1093/nar/gkw280] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 04/06/2016] [Indexed: 12/17/2022] Open
Abstract
Ultraviolet-induced 6-4 photoproducts (6-4PP) and cyclobutane pyrimidine dimers (CPD) can be tolerated by translesion DNA polymerases (TLS Pols) at stalled replication forks or by gap-filling. Here, we investigated the involvement of Polη, Rev1 and Rev3L (Polζ catalytic subunit) in the specific bypass of 6-4PP and CPD in repair-deficient XP-C human cells. We combined DNA fiber assay and novel methodologies for detection and quantification of single-stranded DNA (ssDNA) gaps on ongoing replication forks and postreplication repair (PRR) tracts in the human genome. We demonstrated that Rev3L, but not Rev1, is required for postreplicative gap-filling, while Polη and Rev1 are responsible for TLS at stalled replication forks. Moreover, specific photolyases were employed to show that in XP-C cells, CPD arrest replication forks, while 6-4PP are responsible for the generation of ssDNA gaps and PRR tracts. On the other hand, in the absence of Polη or Rev1, both types of lesion block replication forks progression. Altogether, the data directly show that, in the human genome, Polη and Rev1 bypass CPD and 6-4PP at replication forks, while only 6-4PP are also tolerated by a Polζ-dependent gap-filling mechanism, independent of S phase.
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Affiliation(s)
- Annabel Quinet
- Institute of Biomedical Sciences, University of São Paulo, SP, 05508-000, Brazil
| | - Davi Jardim Martins
- Institute of Biomedical Sciences, University of São Paulo, SP, 05508-000, Brazil
| | | | - Denis Biard
- CEA, IMETI, SEPIA, Team Cellular Engineering and Human Syndromes, F-92265 Fontenay-aux-Roses, France
| | - Alain Sarasin
- CNRS-UMR8200, Université Paris Sud, Institut de Cancérologie Gustave Roussy, 94805 Villejuif, France
| | - Anne Stary
- CNRS-UMR8200, Université Paris Sud, Institut de Cancérologie Gustave Roussy, 94805 Villejuif, France
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de Melo JTA, de Souza Timoteo AR, Lajus TBP, Brandão JA, de Souza-Pinto NC, Menck CFM, Campalans A, Radicella JP, Vessoni AT, Muotri AR, Agnez-Lima LF. XPC deficiency is related to APE1 and OGG1 expression and function. Mutat Res 2016; 784-785:25-33. [PMID: 26811994 DOI: 10.1016/j.mrfmmm.2016.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 01/04/2016] [Accepted: 01/14/2016] [Indexed: 12/11/2022]
Abstract
Oxidative DNA damage is considered to be a major cause of neurodegeneration and internal tumors observed in syndromes that result from nucleotide excision repair (NER) deficiencies, such as Xeroderma Pigmentosum (XP) and Cockayne Syndrome (CS). Recent evidence has shown that NER aids in removing oxidized DNA damage and may interact with base excision repair (BER) enzymes. Here, we investigated APE1 and OGG1 expression, localization and activity after oxidative stress in XPC-deficient cells. The endogenous APE1 and OGG1 mRNA levels were lower in XPC-deficient fibroblasts. However, XPC-deficient cells did not show hypersensitivity to oxidative stress compared with NER-proficient cells. To confirm the impact of an XPC deficiency in regulating APE1 and OGG1 expression and activity, we established an XPC-complemented cell line. Although the XPC complementation was only partial and transient, the transfected cells exhibited greater OGG1 expression and activity compared with XPC-deficient cells. However, the APE1 expression and activity did not significantly change. Furthermore, we observed a physical interaction between the XPC and APE1 proteins. Together, the results indicate that the responses of XPC-deficient cells under oxidative stress may not only be associated with NER deficiency per se but may also include new XPC functions in regulating BER proteins.
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Affiliation(s)
- Julliane Tamara Araújo de Melo
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Ana Rafaela de Souza Timoteo
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Tirzah Braz Petta Lajus
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Juliana Alves Brandão
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Nadja Cristhina de Souza-Pinto
- Laboratório de Genética Mitocondrial, Departamento de Química, Instituto de Química, Universidade de São Paulo-USP, São Paulo, Brazil
| | - Carlos Frederico Martins Menck
- Laboratório de Reparo de DNA, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo-USP, São Paulo, Brazil
| | - Anna Campalans
- CEA, Institut de Radiobiologie Cellulaire et Moléculaire, 18 Route du Panorama, F-92265 Fontenay aux Roses, France
| | - J Pablo Radicella
- CEA, Institut de Radiobiologie Cellulaire et Moléculaire, 18 Route du Panorama, F-92265 Fontenay aux Roses, France
| | - Alexandre Teixeira Vessoni
- Laboratório de Reparo de DNA, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo-USP, São Paulo, Brazil; Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA, USA
| | - Alysson Renato Muotri
- Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA, USA
| | - Lucymara Fassarella Agnez-Lima
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
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Vessoni AT, Quinet A, de Andrade-Lima LC, Martins DJ, Garcia CCM, Rocha CRR, Vieira DB, Menck CFM. Chloroquine-induced glioma cells death is associated with mitochondrial membrane potential loss, but not oxidative stress. Free Radic Biol Med 2016; 90:91-100. [PMID: 26577174 DOI: 10.1016/j.freeradbiomed.2015.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/04/2015] [Indexed: 12/15/2022]
Abstract
Chloroquine (CQ), a quinolone derivative widely used to treat and prevent malaria, has been shown to exert a potent adjuvant effect when combined with conventional glioblastoma therapy. Despite inducing lysosome destabilization and activating p53 in human glioma cells, the mechanisms underlying cell death induced by this drug are poorly understood. Here, we analyzed in a time- and dose-dependent manner, the effects of CQ upon mitochondria integrity, autophagy regulation and redox processes in four human glioma cell lines that differ in their resistance to this drug. NAC-containing media protected cells against CQ-induced loss of mitochondrial membrane potential (MMP), autophagic vacuoles (LC3II) accumulation and loss of cell viability induced by CQ. However, we noticed that part of this protection was due to media acidification in NAC preparations, alerting for problems in experimental procedures using NAC. The results indicate that although CQ induces accumulation of LC3II, mitochondria, and oxidative stress, neither of these events is clearly correlated to cell death induced by this drug. The only event elicited in all cell lines at equitoxic doses of CQ was the loss of MMP, indicating that mitochondrial stability is important for cells resistance to this drug. Finally, the data indicate that higher steady-state MMP values can predict cell resistance to CQ treatment.
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Affiliation(s)
- Alexandre Teixeira Vessoni
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
| | - Annabel Quinet
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
| | - Leonardo Carmo de Andrade-Lima
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
| | - Davi Jardim Martins
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil
| | - Camila Carrião Machado Garcia
- Núcleo de Pesquisa em Ciências Biológicas & Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, 35400-000 Minas Gerais, MG, Brazil.
| | - Clarissa Ribeiro Reily Rocha
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
| | - Debora Braga Vieira
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
| | - Carlos Frederico Martins Menck
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Avenida Professor Lineu Prestes, 1374, 05508-000 São Paulo, SP, Brazil.
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Gomes LR, Vessoni AT, Menck CFM. Three-dimensional microenvironment confers enhanced sensitivity to doxorubicin by reducing p53-dependent induction of autophagy. Oncogene 2015; 34:5329-40. [PMID: 25619836 DOI: 10.1038/onc.2014.461] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 12/02/2014] [Accepted: 12/19/2014] [Indexed: 12/19/2022]
Abstract
Preclinical studies of anticancer drugs are typically performed using cancer cell lines maintained in two-dimensional (2D) cultures, ignoring the influences of the extracellular matrix (ECM) and three-dimensional (3D) microenvironment. In this study, we evaluated the microenvironmental control of human breast cancer cells responses to doxorubicin (DOXO) using the 3D laminin-rich ECM (3D lrECM) cell culture model. Under 3D culture conditions, MCF-7 cells displayed drastic morphological alterations, a decrease in proliferation and elevated sensitivity to DOXO. Interestingly, the chemotherapy-mediated activation of autophagy was compromised in the 3D matrix, suggesting an association between the increased cytotoxicity of DOXO and hindered autophagy induction. Indeed, while chloroquine or ATG5 knockdown potentiated DOXO-induced cell death under the 2D culture conditions, the autophagy inducer rapamycin improved the resistance of 3D-cultured cells to this drug. Moreover, in the monolayer-cultured cells, DOXO treatment led to increases in p53 and DRAM-1 expression, which is a p53-dependent activator of autophagy that functions in response to DNA damage. Conversely, p53 and DRAM-1 expression was impaired in 3D-cultured cells. The knockdown of p53 by shRNA blocked DRAM-1 activation, impaired autophagy induction and sensitized only those cells maintained under 2D conditions to DOXO. In addition, 2D-cultured MDA-MB-231 cells (a p53-mutated breast cancer cell line) not only showed increased sensitivity to DOXO compared with MCF-7 cells but also failed to induce DRAM-1 expression or autophagy. Similar to p53 silencing, DRAM-1 knockdown potentiated DOXO cytotoxicity only in 2D-cultured cells. These results suggest that the 3D tissue microenvironment controls tumor cell sensitivity to DOXO treatment by preventing p53-DRAM-autophagy axis activation.
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Affiliation(s)
- L R Gomes
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - A T Vessoni
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - C F M Menck
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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Abstract
Autophagy is a lysosome-dependent degradation pathway that allows cells to recycle damaged or superfluous cytoplasmic content, such as proteins, organelles, and lipids. As a consequence of autophagy, the cells generate metabolic precursors for macromolecular biosynthesis or ATP generation. Deficiencies in this pathway were associated to several pathological conditions, such as neurodegenerative and cardiac diseases, cancer, and aging. The aim of this review is to summarize recent discoveries showing that autophagy also plays a critical role in stem cell maintenance and in a variety of cell differentiation processes. We also discuss a possible role for autophagy during cellular reprogramming and induced pluripotent stem (iPS) cell generation by taking advantage of ATP generation for chromatin remodeling enzyme activity and mitophagy. Finally, the significance of autophagy modulation is discussed in terms of augmenting efficiency of iPS cell generation and differentiation processes.
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Affiliation(s)
- Alexandre Teixeira Vessoni
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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