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Wang J, Xiang H, Lu Y, Wu T. Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review). Int J Mol Med 2021; 47:55. [PMID: 33604683 PMCID: PMC7895515 DOI: 10.3892/ijmm.2021.4888] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/27/2021] [Indexed: 12/24/2022] Open
Abstract
The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.
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Affiliation(s)
- Junmin Wang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Hongjiao Xiang
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Yifei Lu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Tao Wu
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
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Inhibition of Epstein-Barr Virus Replication in Human Papillomavirus-Immortalized Keratinocytes. J Virol 2019; 93:JVI.01216-18. [PMID: 30381489 DOI: 10.1128/jvi.01216-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022] Open
Abstract
Epstein-Barr virus (EBV) is implicated in the pathogenesis of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OSCC). EBV-associated cancers harbor a latent EBV infection characterized by a lack of viral replication and the expression of viral oncogenes. Cellular changes promoted by HPV are comparable to those shown to facilitate EBV latency, though whether HPV-positive cells support a latent EBV infection has not been demonstrated. Using a model of direct EBV infection into HPV16-immortalized tonsillar cells grown in organotypic raft culture, we showed robust EBV replication in HPV-negative rafts but little to no replication in HPV-immortalized rafts. The reduced EBV replication was independent of immortalization, as human telomerase-immortalized normal oral keratinocytes supported robust EBV replication. Furthermore, we observed reduced EBV lytic gene expression and increased expression of EBER1, a noncoding RNA highly expressed in latently infected cells, in the presence of HPV. The use of human foreskin keratinocyte rafts expressing the HPV16 E6 and/or E7 oncogene(s) (HPV E6 and E7 rafts) showed that E7 was sufficient to reduce EBV replication. EBV replication is dependent upon epithelial differentiation and the differentiation-dependent expression of the transcription factors KLF4 and PRDM1. While KLF4 and PRDM1 levels were unaltered, the expression levels of KLF4 transcriptional targets, including late differentiation markers, were reduced in HPV E6 and E7 rafts compared to their levels in parental rafts. However, the HPV E7-mediated block in EBV replication correlated with delayed expression of early differentiation markers. Overall, this study reveals an HPV16-mediated block in EBV replication, through E7, that may facilitate EBV latency and long-term persistence in the tumor context.IMPORTANCE Using a model examining the establishment of EBV infection in HPV-immortalized tissues, we showed an HPV-induced interruption of the normal EBV life cycle reminiscent of a latent EBV infection. Our data support the notion that a persistent EBV epithelial infection depends upon preexisting cellular alterations and suggest the ability of HPV to promote such changes. More importantly, these findings introduce a model for how EBV coinfection may influence HPV-positive (HPV-pos) OSCC pathogenesis. Latently EBV-infected epithelial cells, as well as other EBV-associated head-and-neck carcinomas, exhibit oncogenic phenotypes commonly seen in HPV-pos OSCC. Therefore, an HPV-induced shift in the EBV life cycle toward latency would not only facilitate EBV persistence but also provide additional viral oncogene expression, which can contribute to the rapid progression of HPV-pos OSCC. These findings provide a step toward defining a role for EBV as a cofactor in HPV-positive oropharyngeal tumors.
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Induction of Interferon Kappa in Human Papillomavirus 16 Infection by Transforming Growth Factor Beta-Induced Promoter Demethylation. J Virol 2018; 92:JVI.01714-17. [PMID: 29437968 DOI: 10.1128/jvi.01714-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/30/2018] [Indexed: 12/18/2022] Open
Abstract
Persistent high-risk human papillomavirus (HPV) infection is the major causal factor in cervical and other anogenital cancers. Because there are currently no therapeutics capable of preventing neoplastic progression of HPV infections, understanding the mechanisms of HPV-mediated persistence, including immune evasion, is a major research priority. The multifunctional growth factor transforming growth factor beta (TGFβ) has been shown to inhibit expression of early viral transcripts from cells harboring integrated HPV genomes or cells infected with retroviruses expressing HPV oncoproteins. However, the mechanism of TGFβ-induced inhibition has not been fully defined. In this study, we have observed a previously uncharacterized ability of TGFβ to repress the differentiation-induced upregulation of late HPV16 gene expression. In addition, interferon kappa (IFN-κ), a keratinocyte-specific, constitutively expressed cytokine suppressed by differentiation, can be transcriptionally induced by TGFβ1. TGFβ-mediated IFN-κ transcription only occurs in cells containing HPV16, and this is due to TGFβ1-mediated reversal of HPV-induced methylation of the IFN-κ promoter through active DNA demethylation mediated by thymine DNA glycosylase (TDG). This novel interaction between growth factor and innate immune signaling may shed light on the mechanisms of HPV persistence and how the virus manipulates both immune and growth factor signaling to promote its life cycle.IMPORTANCE Persistent infection by high-risk HPVs is the primary risk factor for development of HPV-induced cancers. Persistence involves viral evasion of the immune response, including the IFN response. HPV is also known to suppress TGFβ signaling, which inhibits viral gene expression. Here, we show that the TGFβ and IFN pathways are interrelated in the context of HPV16 infection through the upregulation of IFN-κ by TGFβ. The ability of TGFβ to induce IFN-κ promoter demethylation and transcriptional activation provides a new explanation for why HPV has evolved mechanisms to inhibit TGFβ in infected cells.
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Songock WK, Kim SM, Bodily JM. The human papillomavirus E7 oncoprotein as a regulator of transcription. Virus Res 2016; 231:56-75. [PMID: 27818212 DOI: 10.1016/j.virusres.2016.10.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 12/12/2022]
Abstract
High-risk human papillomaviruses (HPVs) encode oncoproteins which manipulate gene expression patterns in the host keratinocytes to facilitate viral replication, regulate viral transcription, and promote immune evasion and persistence. In some cases, oncoprotein-induced changes in host cell behavior can cause progression to cancer, but a complete picture of the functions of the viral oncoproteins in the productive HPV life cycle remains elusive. E7 is the HPV-encoded factor most responsible for maintaining cell cycle competence in differentiating keratinocytes. Through interactions with dozens of host factors, E7 has an enormous impact on host gene expression patterns. In this review, we will examine the role of E7 specifically as a regulator of transcription. We will discuss mechanisms of regulation of cell cycle-related genes by E7 as well as genes involved in immune regulation, growth factor signaling, DNA damage responses, microRNAs, and others pathways. We will also discuss some unanswered questions about how transcriptional regulation by E7 impacts the biology of HPV in both benign and malignant conditions.
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Affiliation(s)
- William K Songock
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Seong-Man Kim
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Jason M Bodily
- Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
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Woodby B, Scott M, Bodily J. The Interaction Between Human Papillomaviruses and the Stromal Microenvironment. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 144:169-238. [PMID: 27865458 PMCID: PMC5727914 DOI: 10.1016/bs.pmbts.2016.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Human papillomaviruses (HPVs) are small, double-stranded DNA viruses that replicate in stratified squamous epithelia and cause a variety of malignancies. Current efforts in HPV biology are focused on understanding the virus-host interactions that enable HPV to persist for years or decades in the tissue. The importance of interactions between tumor cells and the stromal microenvironment has become increasingly apparent in recent years, but how stromal interactions impact the normal, benign life cycle of HPVs, or progression of lesions to cancer is less understood. Furthermore, how productively replicating HPV impacts cells in the stromal environment is also unclear. Here we bring together some of the relevant literature on keratinocyte-stromal interactions and their impacts on HPV biology, focusing on stromal fibroblasts, immune cells, and endothelial cells. We discuss how HPV oncogenes in infected cells manipulate other cells in their environment, and, conversely, how neighboring cells may impact the efficiency or course of HPV infection.
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Affiliation(s)
- B Woodby
- Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - M Scott
- Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - J Bodily
- Louisiana State University Health Sciences Center, Shreveport, LA, United States.
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Zhu H, Luo H, Shen Z, Hu X, Sun L, Zhu X. Transforming growth factor-β1 in carcinogenesis, progression, and therapy in cervical cancer. Tumour Biol 2016; 37:7075-83. [PMID: 27010470 DOI: 10.1007/s13277-016-5028-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 03/18/2016] [Indexed: 01/20/2023] Open
Abstract
Transforming growth factor β1 (TGF-β1) is a multifunctional cytokine that plays important roles in cervical tumor formation, invasion, progression, and metastasis. TGF-β1 functions as a tumor inhibitor in precancerous lesions and early stage cancers of cervix whereas as a tumor promoter in later stage. This switch from a tumor inhibitor to a tumor promoter might be due to various alterations in TGF-β signaling pathway, such as mutations or loss of expression of TGF-β receptors and SMAD proteins. Additionally, the oncoproteins of human papillomaviruses have been shown to stimulate TGF-β1 expression, which in turn suppresses host immune surveillance. Thus, in addition to driving tumor cell migration and metastasis, TGF-β1 is believed to play a key role in promoting human papillomavirus infection by weakening host immune defense. In this article, we will discuss the role of TGF-β1 in the expression, carcinogenesis, progression, and therapy in cervical cancers. A better understanding of this cytokine in cervical carcinogenesis is essential for critical evaluation of this cytokine as a potential prognostic marker and therapeutic target.
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Affiliation(s)
- Haiyan Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, China
| | - Hui Luo
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, China
| | - Zhaojun Shen
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, China
| | - Xiaoli Hu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, China
| | - Luzhe Sun
- Department of Cellular & Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229-3900, USA
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, China.
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Popoca-Cuaya M, Diaz-Chavez J, Hernandez-Monge J, Alvarez-Rios E, Lambert PF, Gariglio P. The HPV16 E6 oncoprotein and UVB irradiation inhibit the tumor suppressor TGFβ pathway in the epidermis of the K14E6 transgenic mouse. Exp Dermatol 2015; 24:430-5. [DOI: 10.1111/exd.12689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Marco Popoca-Cuaya
- Department of Genetics and Molecular Biology; Centro de Investigación y de Estudios Avanzados (CINVESTAV); Mexico City Mexico
| | - Jose Diaz-Chavez
- Unit of Biomedical Research in Cancer; UNAM/Instituto Nacional de Cancerología (INCan); Mexico City Mexico
| | - Jesus Hernandez-Monge
- Department of Genetics and Molecular Biology; Centro de Investigación y de Estudios Avanzados (CINVESTAV); Mexico City Mexico
| | - Elizabeth Alvarez-Rios
- Department of Genetics and Molecular Biology; Centro de Investigación y de Estudios Avanzados (CINVESTAV); Mexico City Mexico
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research; University of Wisconsin School of Medicine and Public Health; Madison WI USA
| | - Patricio Gariglio
- Department of Genetics and Molecular Biology; Centro de Investigación y de Estudios Avanzados (CINVESTAV); Mexico City Mexico
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Graves CA, Abboodi FF, Tomar S, Wells J, Pirisi L. The translational significance of epithelial-mesenchymal transition in head and neck cancer. Clin Transl Med 2014; 3:60. [PMID: 25632320 PMCID: PMC4302251 DOI: 10.1186/s40169-014-0039-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 10/29/2014] [Indexed: 01/01/2023] Open
Abstract
Positive markers of epithelial-mesenchymal transition (EMT) in head and neck cancers complicate clinical management and are associated with reduced survival. We discuss recent translational discoveries in EMT and suggest additional actionable molecular pathways, biomarkers, and clinical agents.
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Affiliation(s)
- Christian A Graves
- Department of Pathology, Microbiology & Immunology, University of South Carolina School of Medicine, Bldg. 1 Room B43 6439 Garners Ferry Rd, Columbia, SC 29208 USA ; Department of Head and Neck Surgery, Wm. Jennings Dorn VA Medical Center, Columbia, SC 29208 USA
| | - Fadi F Abboodi
- Department of Pathology, Microbiology & Immunology, University of South Carolina School of Medicine, Bldg. 1 Room B43 6439 Garners Ferry Rd, Columbia, SC 29208 USA
| | - Swati Tomar
- Department of Pathology, Microbiology & Immunology, University of South Carolina School of Medicine, Bldg. 1 Room B43 6439 Garners Ferry Rd, Columbia, SC 29208 USA
| | - James Wells
- Department of Head and Neck Surgery, Wm. Jennings Dorn VA Medical Center, Columbia, SC 29208 USA
| | - Lucia Pirisi
- Department of Pathology, Microbiology & Immunology, University of South Carolina School of Medicine, Bldg. 1 Room B43 6439 Garners Ferry Rd, Columbia, SC 29208 USA
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Six1 overexpression at early stages of HPV16-mediated transformation of human keratinocytes promotes differentiation resistance and EMT. Virology 2014; 474:144-53. [PMID: 25463612 DOI: 10.1016/j.virol.2014.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/22/2014] [Accepted: 10/07/2014] [Indexed: 11/20/2022]
Abstract
Previous studies in our laboratory discovered that SIX1 mRNA expression increased during in vitro progression of HPV16-immortalized human keratinocytes (HKc/HPV16) toward a differentiation-resistant (HKc/DR) phenotype. In this study, we explored the role of Six1 at early stages of HPV16-mediated transformation by overexpressing Six1 in HKc/HPV16. We found that Six1 overexpression in HKc/HPV16 increased cell proliferation and promoted cell migration and invasion by inducing epithelial-mesenchymal transition (EMT). Moreover, the overexpression of Six1 in HKc/HPV16 resulted in resistance to serum and calcium-induced differentiation, which is the hallmark of the HKc/DR phenotype. Activation of MAPK in HKc/HPV16 overexpressing Six1 is linked to resistance to calcium-induced differentiation. In conclusion, this study determined that Six1 overexpression resulted in differentiation resistance and promoted EMT at early stages of HPV16-mediated transformation of human keratinocytes.
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Habbous S, Pang V, Xu W, Amir E, Liu G. Human papillomavirus and host genetic polymorphisms in carcinogenesis: a systematic review and meta-analysis. J Clin Virol 2014; 61:220-9. [PMID: 25174543 DOI: 10.1016/j.jcv.2014.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 07/26/2014] [Accepted: 07/30/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND As the role of human papillomavirus (HPV) in carcinogenesis continues to rise, the role of genetic factors that modify this risk have become increasingly important. In this study, we reviewed the literature for associations between polymorphisms and HPV in carcinogenesis. OBJECTIVE To identify any associations of genetic polymorphisms with oncogenic HPV in carcinogenesis and to evaluate the methodology used. STUDY DESIGN Systematic literature review of HPV, genetic polymorphisms, and cancer risk. Odds ratios (OR), interaction terms, and p-values were tabulated. Meta-analyses and measures of heterogeneity were estimated using RevMan 5.1. RESULTS The cervix was the most frequently studied cancer site followed by the head and neck. Overall risk of cancer (cancer vs. control) was the most common comparison, whereas reports of initiation (pre-cancer vs. control) and progression (cancer vs. pre-cancer) were rare. Case-series and joint-effect of HPV and genotype on risk was evaluated frequently, but the independent effect of either risk factor alone was rarely provided. P53-Arg72Pro was the most commonly studied polymorphism studied. No consistent interaction was detected by meta-analysis in the HPV(+) [OR 0.98 (0.55-1.76)] or the HPV(-) [OR 1.10 (0.76-1.60)] subsets in head and neck cancer risk. Polymorphisms in genes known to encode proteins that physically interact with HPV were infrequently studied. CONCLUSION No consistent polymorphism-HPV interactions were observed. Study design, choice of candidate polymorphisms/genes, and a focus on overall risk rather than any specific portions of the carcinogenic pathway may have contributed to lack of significant findings.
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Affiliation(s)
- Steven Habbous
- Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9
| | - Vincent Pang
- Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9
| | - Wei Xu
- Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9; Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9
| | - Eitan Amir
- Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9; Division of Medical Oncology and Hematology, Toronto, Ontario, Canada M5G 2M9
| | - Geoffrey Liu
- Ontario Cancer Institute, Princess Margaret Cancer Centre, Toronto, Ontario, Canada M5G 2M9; Medicine and Epidemiology, Dalla Lana School of Public Health, University of Toronto, Canada M5G 2M9.
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TGF-β regulation of gene expression at early and late stages of HPV16-mediated transformation of human keratinocytes. Virology 2013; 447:63-73. [PMID: 24210100 DOI: 10.1016/j.virol.2013.08.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 07/29/2013] [Accepted: 08/27/2013] [Indexed: 01/27/2023]
Abstract
In our in vitro model for HPV16-mediated transformation, HPV16-immortalized human keratinocytes (HKc/HPV16) give rise to differentiation resistant, premalignant cells (HKc/DR). HKc/DR, but not HKc/HPV16, are resistant to growth inhibition by transforming growth factor beta (TGF-β), due to a partial loss of TGF-β receptor type I. We show that TGF-β activates a Smad-responsive reporter construct in HKc/DR to about 50% of the maximum levels of activation observed in HKc/HPV16. To investigate the functional significance of residual TGF-β signaling in HKc/DR, we compared gene expression profiles elicited by TGF-β treatment of HKc/HPV16 and HKc/DR on Agilent 44k human whole genome microarrays. TGF-β altered the expression of cell cycle and MAP kinase pathway genes in HKc/HPV16, but not in HKc/DR. However, epithelial-mesenchymal transition (EMT) responses to TGF-β were comparable in HKc/HPV16 and HKc/DR, indicating that the signaling pathways through which TGF-β elicits growth inhibition diverge from those that induce EMT in HPV16-transformed cells.
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Altomare D, Velidandla R, Pirisi L, Creek KE. Partial loss of Smad signaling during in vitro progression of HPV16-immortalized human keratinocytes. BMC Cancer 2013; 13:424. [PMID: 24047375 PMCID: PMC3848426 DOI: 10.1186/1471-2407-13-424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 09/13/2013] [Indexed: 11/16/2022] Open
Abstract
Background Disruption of the transforming growth factor-beta (TGF-β) signaling pathway is observed in many cancers, including cervical cancer, resulting in TGF-β resistance. While normal human keratinocytes (HKc) and human papillomavirus type 16-immortalized HKc (HKc/HPV16) are sensitive to the growth inhibitory effects of TGF-β, HKc/HPV16 develop resistance to TGF-β1 as they progress in vitro to a differentiation resistant phenotype (HKc/DR). The loss of sensitivity to the antiproliferative effects of TGF-β1 in HKc/DR is due, at least partially, to decreased expression of the TGF-β receptor type I. In the present study, we explored in detail whether alterations in Smad protein levels, Smad phosphorylation, or nuclear localization of Smads in response to TGF-β could contribute to the development of TGF-β resistance during in vitro progression of HKc/HPV16, and whether TGF-β induction of a Smad-responsive reporter gene was altered in HKc/DR. Methods Western blot analysis was used to assess Smad protein levels. In order to study Smad nuclear localization we performed indirect immunofluorescence. In addition, we determined Smad-mediated TGF-β signaling using a luciferase reporter construct. Results We did not find a decrease in protein levels of Smad2, Smad3 or Smad4, or an increase in the inhibitory Smad7 that paralleled the loss of sensitivity to the growth inhibitory effects of TGF-β1 observed in HKc/DR. However, we found diminished Smad2 phosphorylation, and delayed nuclear Smad3 localization in response to TGF-β1 in HKc/DR, compared to normal HKc and TGF-β sensitive HKc/HPV16. In addition, we determined that TGF-β1 induction of a Smad responsive promoter is reduced by about 50% in HKc/DR, compared to HKc/HPV16. Conclusions These results demonstrate that alterations in Smad protein levels are not associated with the loss of response to the antiproliferative effects of TGF-β in HKc/DR, but that diminished and delayed Smad phosphorylation and nuclear localization, and decreased Smad signaling occur in response to TGF-β in HKc/DR.
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Affiliation(s)
- Diego Altomare
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA.
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Ski protein levels increase during in vitro progression of HPV16-immortalized human keratinocytes and in cervical cancer. Virology 2013; 444:100-8. [PMID: 23809940 DOI: 10.1016/j.virol.2013.05.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/23/2013] [Accepted: 05/30/2013] [Indexed: 01/23/2023]
Abstract
We compared the levels of the Ski oncoprotein, an inhibitor of transforming growth factor-beta (TGF-β) signaling, in normal human keratinocytes (HKc), HPV16 immortalized HKc (HKc/HPV16), and differentiation resistant HKc/HPV16 (HKc/DR) in the absence and presence of TGF-β. Steady-state Ski protein levels increased in HKc/HPV16 and even further in HKc/DR, compared to HKc. TGF-β treatment of HKc, HKc/HPV16, and HKc/DR dramatically decreased Ski. TGF-β-induced Ski degradation was delayed in HKc/DR. Ski and phospho-Ski protein levels are cell cycle dependent with maximal Ski expression and localization to centrosomes and mitotic spindles during G2/M. ShRNA knock down of Ski in HKc/DR inhibited cell proliferation. More intense nuclear and cytoplasmic Ski staining and altered Ski localization were found in cervical cancer samples compared to adjacent normal tissue in a cervical cancer tissue array. Overall, these studies demonstrate altered Ski protein levels, degradation and localization in HPV16-transformed human keratinocytes and in cervical cancer.
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Epigenetic Alteration by DNA Promoter Hypermethylation of Genes Related to Transforming Growth Factor-β (TGF-β) Signaling in Cancer. Cancers (Basel) 2011; 3:982-93. [PMID: 24212650 PMCID: PMC3756400 DOI: 10.3390/cancers3010982] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 12/18/2022] Open
Abstract
Epigenetic alterations in cancer, especially DNA methylation and histone modification, exert a significant effect on the deregulated expression of cancer-related genes and lay an epigenetic pathway to carcinogenesis and tumor progression. Global hypomethylation and local hypermethylation of CpG islands in the promoter region, which result in silencing tumor suppressor genes, constitute general and major epigenetic modification, the hallmark of the neoplastic epigenome. Additionally, methylation-induced gene silencing commonly affects a number of genes and increases with cancer progression. Indeed, cancers with a high degree of methylation (CpG island methylator phenotype/CIMP) do exist and represent a distinct subset of certain cancers including colorectal, bladder and kidney. On the other hand, signals from the microenvironment, especially those from transforming growth factor-β (TGF-β), induce targeted de novo epigenetic alterations of cancer-related genes. While TGF-β signaling has been implicated in two opposite roles in cancer, namely tumor suppression and tumor promotion, its deregulation is also partly induced by epigenetic alteration itself. Although the epigenetic pathway to carcinogenesis and cancer progression has such reciprocal complexity, the important issue is to identify genes or signaling pathways that are commonly silenced in various cancers in order to find early diagnostic and therapeutic targets. In this review, we focus on the epigenetic alteration by DNA methylation and its role in molecular modulations of the TGF-β signaling pathway that cause or underlie altered cancer-related gene expression in both phases of early carcinogenesis and late cancer progression.
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