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Buono MF, Benavente ED, Daniels M, Mol BM, Mekke JM, de Borst GJ, de Kleijn DPV, van der Laan SW, Pasterkamp G, Onland-Moret C, Mokry M, den Ruijter HM. X chromosome inactivation skewing is common in advanced carotid atherosclerotic lesions in females and predicts secondary peripheral artery events. Biol Sex Differ 2023; 14:43. [PMID: 37408072 DOI: 10.1186/s13293-023-00527-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/24/2023] [Indexed: 07/07/2023] Open
Abstract
BACKGROUND AND AIM Sex differences in atherosclerosis have been described with female plaques being mostly perceived as stable and fibrous. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men have been linked to cardiovascular health. In women, X-linked mechanisms such as X chromosome inactivation (XCI) skewing is common in several tissues. Yet, information on the role of XCI in female atherosclerotic plaques is lacking. Here, we investigated the presence of XCI skewing in advanced atherosclerotic lesions and its association with cardiovascular risk factors, histological plaque data, and clinical data. METHODS XCI skewing was quantified in 154 atherosclerotic plaque and 55 blood DNA samples of women included in the Athero-Express study. The skewing status was determined performing the HUMARA assay. Then, we studied the relationship of XCI skewing in female plaque and cardiovascular risk factors using regression models. In addition, we studied if plaque XCI predicted plaque composition, and adverse events during 3-years follow-up using Cox proportional hazard models. RESULTS XCI skewing was detected in 76 of 154 (49.4%) plaques and in 27 of 55 (67%) blood samples. None of the clinical risk factors were associated with plaque skewing. Plaque skewing was more often detected in plaques with a plaque hemorrhage (OR [95% CI]: 1.44 [1.06-1.98], P = 0.02). Moreover, skewed plaques were not associated with a higher incidence of composite and major events but were specifically associated with peripheral artery events during a 3-year follow-up period in a multivariate model (HR [95%CI]: 1.46 [1.09-1.97]; P = 0.007). CONCLUSIONS XCI skewing is common in carotid plaques of females and is predictive for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.
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Affiliation(s)
- Michele F Buono
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Ernest Diez Benavente
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Mark Daniels
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Barend M Mol
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Joost M Mekke
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Gert J de Borst
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dominique P V de Kleijn
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sander W van der Laan
- Central Diagnostics Laboratory, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Gerard Pasterkamp
- Central Diagnostics Laboratory, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Charlotte Onland-Moret
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Michal Mokry
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Central Diagnostics Laboratory, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Hester M den Ruijter
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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2
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Roberts AL, Morea A, Amar A, Zito A, El-Sayed Moustafa JS, Tomlinson M, Bowyer RCE, Zhang X, Christiansen C, Costeira R, Steves CJ, Mangino M, Bell JT, Wong CCY, Vyse TJ, Small KS. Age acquired skewed X chromosome inactivation is associated with adverse health outcomes in humans. eLife 2022; 11:78263. [PMID: 36412098 PMCID: PMC9681199 DOI: 10.7554/elife.78263] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Ageing is a heterogenous process characterised by cellular and molecular hallmarks, including changes to haematopoietic stem cells and is a primary risk factor for chronic diseases. X chromosome inactivation (XCI) randomly transcriptionally silences either the maternal or paternal X in each cell of 46, XX females to balance the gene expression with 46, XY males. Age acquired XCI-skew describes the preferential selection of cells across a tissue resulting in an imbalance of XCI, which is particularly prevalent in blood tissues of ageing females, and yet its clinical consequences are unknown. METHODS We assayed XCI in 1575 females from the TwinsUK population cohort using DNA extracted from whole blood. We employed prospective, cross-sectional, and intra-twin study designs to characterise the relationship of XCI-skew with molecular and cellular measures of ageing, cardiovascular disease risk, and cancer diagnosis. RESULTS We demonstrate that XCI-skew is independent of traditional markers of biological ageing and is associated with a haematopoietic bias towards the myeloid lineage. Using an atherosclerotic cardiovascular disease risk score, which captures traditional risk factors, XCI-skew is associated with an increased cardiovascular disease risk both cross-sectionally and within XCI-skew discordant twin pairs. In a prospective 10 year follow-up study, XCI-skew is predictive of future cancer incidence. CONCLUSIONS Our study demonstrates that age acquired XCI-skew captures changes to the haematopoietic stem cell population and has clinical potential as a unique biomarker of chronic disease risk. FUNDING KSS acknowledges funding from the Medical Research Council [MR/M004422/1 and MR/R023131/1]. JTB acknowledges funding from the ESRC [ES/N000404/1]. MM acknowledges funding from the National Institute for Health Research (NIHR)-funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust in partnership with King's College London. TwinsUK is funded by the Wellcome Trust, Medical Research Council, European Union, Chronic Disease Research Foundation (CDRF), Zoe Global Ltd and the National Institute for Health Research (NIHR)-funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust in partnership with King's College London.
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Affiliation(s)
- Amy L Roberts
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Alessandro Morea
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom.,Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Ariella Amar
- Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Antonino Zito
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | | | - Max Tomlinson
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom.,Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Ruth C E Bowyer
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Xinyuan Zhang
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Colette Christiansen
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Ricardo Costeira
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Claire J Steves
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Massimo Mangino
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom.,NIHR Biomedical Research Centre, Guy's and St Thomas' Foundation Trust, London, United Kingdom
| | - Jordana T Bell
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
| | - Chloe C Y Wong
- Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Timothy J Vyse
- Department of Medical and Molecular Genetics, King's College London, London, United Kingdom
| | - Kerrin S Small
- Department of Twin Research & Genetic Epidemiology, King's College London, London, United Kingdom
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3
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Yu WY, Zhang Y, Li MK, Yang ZY, Fung WK, Zhao PZ, Zhou JY. BEXCIS: Bayesian methods for estimating the degree of the skewness of X chromosome inactivation. BMC Bioinformatics 2022; 23:193. [PMID: 35610583 PMCID: PMC9128296 DOI: 10.1186/s12859-022-04721-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/09/2022] [Indexed: 11/10/2022] Open
Abstract
Background X chromosome inactivation (XCI) is an epigenetic phenomenon that one of two X chromosomes in females is transcriptionally silenced during early embryonic development. Skewed XCI has been reported to be associated with some X-linked diseases. There have been several methods measuring the degree of the skewness of XCI. However, these methods may still have several limitations. Results We propose a Bayesian method to obtain the point estimate and the credible interval of the degree of XCI skewing by incorporating its prior information of being between 0 and 2. We consider a normal prior and a uniform prior for it (respectively denoted by BN and BU). We also propose a penalized point estimate based on the penalized Fieller’s method and derive the corresponding confidence interval. Simulation results demonstrate that the BN and BU methods can solve the problems of extreme point estimates, noninformative intervals, empty sets and discontinuous intervals. The BN method generally outperforms other methods with the lowest mean squared error in the point estimation, and well controls the coverage probability with the smallest median and the least variation of the interval width in the interval estimation. We apply all the methods to the Graves’ disease data and the Minnesota Center for Twin and Family Research data, and find that SNP rs3827440 in the Graves’ disease data may undergo skewed XCI towards the allele C. Conclusions We recommend the BN method for measuring the degree of the skewness of XCI in practice. The R package BEXCIS is publicly available at https://github.com/Wen-YiYu/BEXCIS. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-022-04721-y.
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Affiliation(s)
- Wen-Yi Yu
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou, China
| | - Yu Zhang
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou, China
| | - Meng-Kai Li
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou, China
| | - Zi-Ying Yang
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.,Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou, China
| | - Wing Kam Fung
- Department of Statistics and Actuarial Science, The University of Hong Kong, Hong Kong, China
| | - Pei-Zhen Zhao
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Ji-Yuan Zhou
- Department of Biostatistics, State Key Laboratory of Organ Failure Research, Ministry of Education, and Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China. .,Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou, China.
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4
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Preferential X Chromosome Inactivation as a Mechanism to Explain Female Preponderance in Myasthenia Gravis. Genes (Basel) 2022; 13:genes13040696. [PMID: 35456502 PMCID: PMC9031138 DOI: 10.3390/genes13040696] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/04/2022] [Accepted: 04/13/2022] [Indexed: 11/17/2022] Open
Abstract
Myasthenia gravis (MG) is a neuromuscular autoimmune disease characterized by prevalence in young women (3:1). Several mechanisms proposed as explanations for gender bias, including skewed X chromosome inactivation (XCI) and dosage or sex hormones, are often involved in the development of autoimmunity. The skewed XCI pattern can lead to an unbalanced expression of some X-linked genes, as observed in several autoimmune disorders characterized by female predominance. No data are yet available regarding XCI and MG. We hypothesize that the preferential XCI pattern may contribute to the female bias observed in the onset of MG, especially among younger women. XCI analysis was performed on blood samples of 284 women between the ages of 20 and 82. XCI was tested using the Human Androgen Receptor Assay (HUMARA). XCI patterns were classified as random (XCI < 75%) and preferential (XCI ≥ 75%). In 121 informative patients, the frequency of skewed XCI patterns was 47%, significantly higher than in healthy controls (17%; p ≤ 0.00001). Interestingly, the phenomenon was observed mainly in younger patients (<45 years; p ≤ 0.00001). Furthermore, considering the XCI pattern and the other clinical characteristics of patients, no significant differences were found. In conclusion, we observed preferential XCI in MG female patients, suggesting its potential role in the aetiology of MG, as observed in other autoimmune diseases in women.
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5
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Dhabhai B, Sharma A, Maciaczyk J, Dakal TC. X-Linked Tumor Suppressor Genes Act as Presumed Contributors in the Sex Chromosome-Autosome Crosstalk in Cancers. Cancer Invest 2021; 40:103-110. [PMID: 34519229 DOI: 10.1080/07357907.2021.1981364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Since the human genome contains about 6% of tumor suppressor genes (TSGs) and the X chromosome alone holds a substantial share (2%), herein, we have discussed exclusively the relative contribution of X-linked human TSGs that appear to be primarily involved in 32 different cancer types. Our analysis showed that, (a) the majority of X-linked TSGs are primarily involved in the dysregulation of breast cancer, followed by prostate cancer, (b) Despite being escaped from X chromosome inactivation (XCI), a clear pattern of altered promoter methylation linked to the mutational burden was observed among them. (c) X-linked TSGs (mainly on the q-arm) maintain spatial and genetic interactions with certain autosomal loci. Corroborating our previous findings that loss/gain of entire sex chromosomes (in XO and XXY syndromes) can profoundly affect the epigenetic status of autosomes we herein suggest that X-linked TSGs alone can also contribute significantly in the dynamics this sex chromosome-autosome crosstalk to restructure the cancer genome.
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Affiliation(s)
- Bhanupriya Dhabhai
- Genome and Computational Biology Lab, Department of Biotechnology, Mohanlal Sukhadia University, Udaipur, India
| | - Amit Sharma
- Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Bonn, Bonn, Germany
| | - Jarek Maciaczyk
- Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Bonn, Bonn, Germany.,Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Tikam Chand Dakal
- Genome and Computational Biology Lab, Department of Biotechnology, Mohanlal Sukhadia University, Udaipur, India
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6
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Zhang Y, Li X, Gibson A, Edberg J, Kimberly RP, Absher DM. Skewed allelic expression on X chromosome associated with aberrant expression of XIST on systemic lupus erythematosus lymphocytes. Hum Mol Genet 2021; 29:2523-2534. [PMID: 32628254 DOI: 10.1093/hmg/ddaa131] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/27/2020] [Accepted: 06/11/2020] [Indexed: 12/24/2022] Open
Abstract
A common feature of autoimmune diseases, including systemic lupus erythematosus (SLE), is an increased prevalence in women. However, the molecular basis for sex disparity in SLE remains poorly understood. To examine the role of X-linked transcription in SLE adaptive immune cells, we performed RNA-seq in T cell and B cell subsets from either healthy donors or patients with SLE. Analyses of allelic expression (AE) profiles identified a pattern of increased allelic imbalance across the entire X chromosome in SLE lymphocytes. X-linked genes exhibiting AE in SLE had an extensive overlap with genes known to escape X chromosome inactivation (XCI). XIST RNA was overexpressed in SLE patients. Differential XIST expression correlated with AE profiles more positively at X-linked genes than the genome-wide background. Analysis of three independent RNA-seq data verified the XIST-associated skewed AE on X chromosome in SLE. Integrative analyses of DNA methylation profiles showed an increased variability of DNA methylation levels at these AE-related X-linked genes. In cultured lymphoblastic cells, knockdown of XIST specifically altered allelic imbalance patterns between X chromosomes. Our study provides genetic evidence that upregulation of XIST accompanied with more skewed allelic expression on X chromosome is associated with the pathogenesis of SLE and may provide mechanistic insights into the increased incidence of SLE in females.
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Affiliation(s)
- Yanfeng Zhang
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Xinrui Li
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Andrew Gibson
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jeffrey Edberg
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Robert P Kimberly
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Devin M Absher
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
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7
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Sharma A, Liu H, Herwig-Carl MC, Chand Dakal T, Schmidt-Wolf IGH. Epigenetic Regulatory Enzymes: mutation Prevalence and Coexistence in Cancers. Cancer Invest 2021; 39:257-273. [PMID: 33411587 DOI: 10.1080/07357907.2021.1872593] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epigenetic regulation is an important layer of transcriptional control with the particularity to affect the broad spectrum of genome. Over the years, largely due to the substantial number of recurrent mutations, there have been hundreds of novel driver genes characterized in various cancers. Additionally, the relative contribution of two dysregulated epigenomic entities (DNA methylation and histone modifications) that gradually drive the cancer phenotype remains in the research focus. However, a complex scenario arises when the disease phenotype does not harbor any relevant mutation or an abnormal transcription level. Although the cancer landscape involves the contribution of multiple genetic and non-genetic factors, herein, we discuss specifically the mutation spectrum of epigenetically-related enzymes in cancer. In addition, we address the coexistence of these two epigenetic entities in malignant human diseases, especially cancer. We suggest that the study of epigenetically-related somatic mutations in the early cellular differentiation stage of embryonic development might help to understand their later-staged footprints in the cancer genome. Furthermore, understanding the co-occurrence and/or inverse association of different disease types and redefining the general definition of "healthy" controls could provide insights into the genome reorganization.
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Affiliation(s)
- Amit Sharma
- Department of Integrated Oncology, CIO Bonn, University Hospital Bonn, Bonn, Germany.,Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Hongde Liu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing, China
| | | | - Tikam Chand Dakal
- Department of Biotechnology, Mohanlal Sukhadia University, Rajasthan, India
| | - Ingo G H Schmidt-Wolf
- Department of Integrated Oncology, CIO Bonn, University Hospital Bonn, Bonn, Germany
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8
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Hao M, Zhao X, Xu W. Competing risk modeling and testing for X-chromosome genetic association. Comput Stat Data Anal 2020. [DOI: 10.1016/j.csda.2020.107007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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9
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Han D, Hao M, Qu L, Xu W. A novel model for the X-chromosome inactivation association on survival data. Stat Methods Med Res 2020; 29:1305-1314. [PMID: 31258049 DOI: 10.1177/0962280219859037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The X-linked genetic association is overlooked in most of the genetic studies because of the complexity of X-chromosome inactivation process. In fact, the biological process of the gene at the same locus can vary across different subjects. Besides, the skewness of X-chromosome inactivation is inherently subject-specific (even tissue-specific within subjects) and cannot be accurately represented by a population-level parameter. To tackle this issue, a new model is proposed to incorporate the X-linked genetic association into right-censored survival data. The novel model can present that the X-linked genes on different subjects may go through different biological processes via a mixed distribution. Further, a random effect is employed to describe the uncertainty of the biological process for every subject. The proposed method can derive the probability for the escape of X-chromosome inactivation and derive the unbiased estimates of the model parameters. The Legendre-Gauss Quadrature method is used to approximate the integration over the random effect. Finite sample performance of this method is examined via extensive simulation studies. An application is illustrated with the implementation on a cancer genetic study with right-censored survival data.
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Affiliation(s)
- Dongxiao Han
- Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
| | - Meiling Hao
- School of Statistics, University of International Business and Economics, Beijing, China
| | - Lianqiang Qu
- School of Mathematics and Statistics, Central China Normal University, Wuhan, China
| | - Wei Xu
- Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
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10
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Heritability of skewed X-inactivation in female twins is tissue-specific and associated with age. Nat Commun 2019; 10:5339. [PMID: 31767861 PMCID: PMC6877649 DOI: 10.1038/s41467-019-13340-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 11/04/2019] [Indexed: 12/16/2022] Open
Abstract
Female somatic X-chromosome inactivation (XCI) balances the X-linked transcriptional dosages between the sexes. Skewed XCI toward one parental X has been observed in several complex human traits, but the extent to which genetics and environment influence skewed XCI is largely unexplored. To address this, we quantify XCI-skew in multiple tissues and immune cell types in a twin cohort. Within an individual, XCI-skew differs between blood, fat and skin tissue, but is shared across immune cell types. XCI skew increases with age in blood, but not other tissues, and is associated with smoking. XCI-skew is increased in twins with Rheumatoid Arthritis compared to unaffected identical co-twins. XCI-skew is heritable in blood of females >55 years old (h2 = 0.34), but not in younger individuals or other tissues. This results in a Gene x Age interaction that shifts the functional dosage of all X-linked heterozygous loci in a tissue-restricted manner. Skewing of X chromosome inactivation (XCI) occurs when the silencing of one parental X chromosome is non-random. Here, Zito et al. report XCI patterns in lymphoblastoid cell lines, blood, subcutaneous adipose tissue samples and skin samples of monozygotic and dizygotic twins and find XCI skew to associate with tissue and age.
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11
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Li F, Li H, Zhang L, Li W, Deng J, An M, Wu S, Lu X, Ma R, Wang Y, Guo B, Lu J, Zhou Y. X chromosome-linked long noncoding RNA lnc-XLEC1 regulates c-Myc-dependent cell growth by collaborating with MBP-1 in endometrial cancer. Int J Cancer 2019; 145:927-940. [PMID: 30698832 DOI: 10.1002/ijc.32166] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 12/12/2018] [Accepted: 12/20/2018] [Indexed: 01/05/2023]
Abstract
LncRNAs (long noncoding RNAs) are noncoding transcripts that are more than 200 nt long and have been described as the largest subclass in the noncoding transcriptome in humans. Although studies of lncRNAs in cancer have been continuing for a long time, no much has been known about X chromosome-linked lncRNAs. Here, by using RNA-seq we report the identification of a new X chromosome-linked lncRNA (lnc-XLEC1) that is aberrantly downregulated during the development of endometrial carcinoma (EC). The overexpression of lnc-XLEC1 reduces the migration and proliferation of EC cells. Flow cytometry analysis indicated that lnc-XLEC1 overexpression resulted in a substantial accumulation of EC cells in the G1 phase. In addition, lnc-XLEC1 had inhibitive effects that may result from its collaboration with MBP-1 during the suppression of the c-Myc expression and the negative regulating of the Cdk/Rb/E2F pathway. The anti-tumor effects of lnc-XLEC1 on EC progression suggest that lnc-XLEC1 has some potential value in anti-carcinoma therapies and deserves further investigation. Our study reported for the first time that the lnc-XLEC1 might be related to the incidence and prognosis of EC. Moreover, we discovered that this process might be related to somatic X dosage compensation and skewed X chromosome inactivation (SXCI).
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Affiliation(s)
- Fang Li
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Hua Li
- Department of Obstetrics and Gynecology, Third Hospital, Peking University, Beijing, China
| | - Liyuan Zhang
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Wei Li
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Jieqiong Deng
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Mingxing An
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Siqi Wu
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Xiaoxiao Lu
- Department of English study, Faculty of Languages and Literatures, Ludwig Maximilian University (LMU), Munich, Germany
| | - Rui Ma
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Yirong Wang
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Binbin Guo
- Department of Genetics, Medical College of Soochow University, Suzhou, China
| | - Jiachun Lu
- Department of Epidemiology, The State Key Lab of Respiratory Disease, The First Affiliated Hospital, The Institute for Chemical Carcinogenesis, School of Public Health, Guangzhou Medical University, Guangzhou, China
| | - Yifeng Zhou
- Department of Genetics, Medical College of Soochow University, Suzhou, China
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12
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Li W, Zhang L, Guo B, Deng J, Wu S, Li F, Wang Y, Lu J, Zhou Y. Exosomal FMR1-AS1 facilitates maintaining cancer stem-like cell dynamic equilibrium via TLR7/NFκB/c-Myc signaling in female esophageal carcinoma. Mol Cancer 2019; 18:22. [PMID: 30736860 PMCID: PMC6367809 DOI: 10.1186/s12943-019-0949-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023] Open
Abstract
Background Though esophageal cancer is three to four times more common among males than females worldwide, this type of cancer still ranks in the top incidence among women, even more than the female specific cancer types. The occurrence is currently attributed to extrinsic factors, including tobacco use and alcohol consumption. However, limited attention has been given to gender-specific intrinsic genetic factors, especially in female. Methods We re-annotated a large cohort of microarrays on 179 ESCC patients and identified female-specific differently expressed lncRNAs. The associations between FMR1-AS1 and the risk and prognosis of ESCC were examined in 206 diagnosed patients from eastern China and validated in 188 additional patients from southern China. The effects of FMR1-AS1 on the malignant phenotypes on female ESCC cells were detected in vitro and in vivo. ChIRP-MS, reporter gene assays and EMSA were conducted to identify the interaction and regulation among FMR1-AS1, TLR7 and NFκB. Results We found FMR1-AS1 expression is exclusively altered and closely associated with the level of sXCI in female ESCC patients, and its overexpression may correlate to poor clinical outcome. ChIRP-MS data indicate that FMR1-AS1 could be packaged into exosomes and released into tumor microenvironment. Functional studies demonstrated that FMR1-AS1 could bind to endosomal toll-like receptor 7 (TLR7) and activate downstream TLR7-NFκB signaling, promoting the c-Myc expression, thus inducing ESCC cell proliferation, anti-apoptosis and invasion ability. Exosome incubation and co-xenograft assay indicate that FMR1-AS1 exosomes may secreted from ESCC CSCs, transferring stemness phenotypes to recipient non-CSCs in tumor microenvironment. Furthermore, we also found a correlation between the serum levels of FMR1-AS1 and the overall survival (OS) of the female ESCC patients. Conclusions Our results highlighted exosomal FMR1-AS1 in maintaining CSC dynamic interconversion state through the mechanism of activating TLR7-NFκB signaling, upregulating c-Myc level in recipient cells, which may be taken as an attractive target approach for advancing current precision cancer therapeutics in female patients. Electronic supplementary material The online version of this article (10.1186/s12943-019-0949-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei Li
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Liyuan Zhang
- Department of Radiotherapy & Oncology, The Second Affiliated Hospital of Soochow University, San Xiang Road No. 1055, Suzhou, 215004, China
| | - Binbin Guo
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Jieqiong Deng
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Siqi Wu
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Fang Li
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Yirong Wang
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China
| | - Jiachun Lu
- The Institute for Chemical Carcinogenesis, The State Key Lab of Respiratory Disease, Guangzhou Medical University, Guangzhou, 510182, China
| | - Yifeng Zhou
- Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China.
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13
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Xu SQ, Zhang Y, Wang P, Liu W, Wu XB, Zhou JY. A statistical measure for the skewness of X chromosome inactivation based on family trios. BMC Genet 2018; 19:109. [PMID: 30518319 PMCID: PMC6282303 DOI: 10.1186/s12863-018-0694-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 11/08/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND X chromosome inactivation (XCI) is an important gene regulation mechanism in females to equalize the expression levels of X chromosome between two sexes. Generally, one of two X chromosomes in females is randomly chosen to be inactivated. Nonrandom XCI (XCI skewing) is also observed in females, which has been reported to play an important role in many X-linked diseases. However, there is no statistical measure available for the degree of the XCI skewing based on family data in population genetics. RESULTS In this article, we propose a statistical approach to measure the degree of the XCI skewing based on family trios, which is represented by a ratio of two genotypic relative risks in females. The point estimate of the ratio is obtained from the maximum likelihood estimates of two genotypic relative risks. When parental genotypes are missing in some family trios, the expectation-conditional-maximization algorithm is adopted to obtain the corresponding maximum likelihood estimates. Further, the confidence interval of the ratio is derived based on the likelihood ratio test. Simulation results show that the likelihood-based confidence interval has an accurate coverage probability under the situations considered. Also, we apply our proposed method to the rheumatoid arthritis data from USA for its practical use, and find out that a locus, rs2238907, may undergo the XCI skewing against the at-risk allele. But this needs to be further confirmed by molecular genetics. CONCLUSIONS The proposed statistical measure for the skewness of XCI is applicable to complete family trio data or family trio data with some paternal genotypes missing. The likelihood-based confidence interval has an accurate coverage probability under the situations considered. Therefore, our proposed statistical measure is generally recommended in practice for discovering the potential loci which undergo the XCI skewing.
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Affiliation(s)
- Si-Qi Xu
- State Key Laboratory of Organ Failure Research, Ministry of Education and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou, China
| | - Yu Zhang
- State Key Laboratory of Organ Failure Research, Ministry of Education and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou, China
| | - Peng Wang
- State Key Laboratory of Organ Failure Research, Ministry of Education and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou, China
| | - Wei Liu
- State Key Laboratory of Organ Failure Research, Ministry of Education and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou, China
| | - Xian-Bo Wu
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, China.
| | - Ji-Yuan Zhou
- State Key Laboratory of Organ Failure Research, Ministry of Education and Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Biostatistics, School of Public Health, Southern Medical University, Guangzhou, China.
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14
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Wang J, Talluri R, Shete S. Selection of X-chromosome Inactivation Model. Cancer Inform 2017; 16:1176935117747272. [PMID: 29308008 PMCID: PMC5751921 DOI: 10.1177/1176935117747272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/18/2017] [Indexed: 11/15/2022] Open
Abstract
To address the complexity of the X-chromosome inactivation (XCI) process, we previously developed a unified approach for the association test for X-chromosomal single-nucleotide polymorphisms (SNPs) and the disease of interest, accounting for different biological possibilities of XCI: random, skewed, and escaping XCI. In the original study, we focused on the SNP-disease association test but did not provide knowledge regarding the underlying XCI models. One can use the highest likelihood ratio (LLR) to select XCI models (max-LLR approach). However, that approach does not formally compare the LLRs corresponding to different XCI models to assess whether the models are distinguishable. Therefore, we propose an LLR comparison procedure (comp-LLR approach), inspired by the Cox test, to formally compare the LLRs of different XCI models to select the most likely XCI model that describes the underlying XCI process. We conduct simulation studies to investigate the max-LLR and comp-LLR approaches. The simulation results show that compared with the max-LLR, the comp-LLR approach has higher probability of identifying the correct underlying XCI model for the scenarios when the underlying XCI process is random XCI, escaping XCI, or skewed XCI to the deleterious allele. We applied both approaches to a head and neck cancer genetic study to investigate the underlying XCI processes for the X-chromosomal genetic variants.
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Affiliation(s)
- Jian Wang
- Department of Biostatistics–Unit 1411, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Rajesh Talluri
- Department of Data Science, The University of Mississippi Medical Center, Jackson, MS, USA
| | - Sanjay Shete
- Department of Biostatistics–Unit 1411, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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15
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Sharma A, Kaut O, Pavlova A, Fröhlich H, Ahmad A, Schmitt I, El-Maarri O, Oldenburg J, Wüllner U. Skewed X-chromosome inactivation and XIST locus methylation levels do not contribute to the lower prevalence of Parkinson's disease in females. Neurobiol Aging 2017; 57:248.e1-248.e5. [PMID: 28663000 DOI: 10.1016/j.neurobiolaging.2017.05.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 05/19/2017] [Accepted: 05/27/2017] [Indexed: 10/19/2022]
Abstract
Parkinson's disease (PD) is a degenerative disorder of the nervous system and the cause of the majority of sporadic cases is unknown. Females are relatively protected from PD as compared with males and linkage studies suggested a PD susceptibility locus on the X chromosome. To determine a putative association of skewed X-chromosome inactivation (XCI) and PD, we examined XCI patterns using a human androgen receptor gene-based assay (HUMARA) and did not identify any association of skewed or random X inactivation with clinical heterogeneity among female PD patients. In addition, we sought to determine methylation-specific changes at the X-inactive specific transcript (XIST) locus, which is known to be responsible for initiating X inactivation. We observed a trend towards hypomethylation in the gene body region of the XIST locus in PD females which did not reach significance. Furthermore, we extended our analysis of DNA methylation across the entire X-chromosome which revealed no methylation-specific differences between PD females and healthy controls. Thus, we propose that skewed XCI and methylation levels on the entire X chromosome did not reveal changes which could account for the decreased PD susceptibility in females or suitable to use as a biomarker.
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Affiliation(s)
- Amit Sharma
- Department of Neurology, University Clinic Bonn, Bonn, Germany; Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany
| | - Oliver Kaut
- Department of Neurology, University Clinic Bonn, Bonn, Germany
| | - Anna Pavlova
- Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany
| | - Holger Fröhlich
- Bonn-Aachen International Center for IT (B-IT), Bonn, Germany; UCB Biosciences GmbH, Monheim, Germany
| | - Ashar Ahmad
- Bonn-Aachen International Center for IT (B-IT), Bonn, Germany
| | - Ina Schmitt
- Department of Neurology, University Clinic Bonn, Bonn, Germany
| | - Osman El-Maarri
- Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany; Department of Natural Sciences, Lebanese American University, Byblos, Beirut, Lebanon
| | - Johannes Oldenburg
- Institute of Experimental Hematology and Transfusion Medicine, Bonn, Germany
| | - Ullrich Wüllner
- Department of Neurology, University Clinic Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
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16
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Wu C, Sun Z. X chromosome abnormal inactivation: a unique factor for women's diseases? Epigenomics 2016; 8:447-50. [DOI: 10.2217/epi.16.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Cuijiao Wu
- Department of Histology & Embryology, Qingdao University Medical School, Qingdao, Shandong, China
| | - Zhifu Sun
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
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17
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Vacca M, Della Ragione F, Scalabrì F, D'Esposito M. X inactivation and reactivation in X-linked diseases. Semin Cell Dev Biol 2016; 56:78-87. [PMID: 26994527 DOI: 10.1016/j.semcdb.2016.03.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/22/2022]
Abstract
X chromosome inactivation (XCI) is the phenomenon by which mammals compensate for dosage of X-linked genes in females (XX) versus males (XY). XCI patterns can be random or show extreme skewing, and can modify the mode of inheritance of X-driven phenotypes, which contributes to the variability of human pathologies. Recent findings have shown reversibility of the XCI process, which has opened new avenues in the approaches used for the treatment of X-linked diseases.
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Affiliation(s)
- Marcella Vacca
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
| | | | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
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18
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Androgen Receptor CAG Repeat Length and Estrogen Receptor Status in Postmenopausal Breast Cancer Prognosis. Int J Biol Markers 2015; 30:e418-24. [DOI: 10.5301/jbm.5000176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2015] [Indexed: 11/20/2022]
Abstract
Purpose The influence of the androgen receptor (AR) CAG repeat polymorphism on breast cancer is controversial. We investigated the combined effects of CAG repeat length and estrogen receptor (ER) status on prognosis in 355 postmenopausal women with primary breast cancer. Methods CAG repeat length was determined by the HUMARA test. Relapse-free survival (RFS) and overall survival (OS) according to the X-weighted CAG repeat biallelic mean (XWBM) were investigated by univariate and multivariate analysis. Results XWBM was not associated with RFS or OS, but a significant interaction between XWBM and ER status (p = 0.002) was found for OS. ER-negative patients with median XWBM <20 showed lower OS than ER-negative/XWBM ≥20 patients (HR = 0.270; 95% Cl: 0.073-0.999). ER-negative/XWBM <20 patients also had significantly lower OS than ER-positive women, irrespective of CAG repeat length (p<0.001). Accordingly, estimated OS was lowest in ER-negative patients with XWBM <20 (OS: 0.63, 95% CI: 0.41-0.79) and highest in ER-positive patients with XWBM <20 (OS: 0.95, 95% CI: 0.90-0.97). Conclusions Our data suggest that short CAG repeat length is associated with increased risk of death in ER-negative disease but is related to better survival when ER is expressed. These findings are in agreement with the hypothesis that AR may stimulate or inhibit breast cancer growth depending on ER status, AR transactivation, and the endocrine-metabolic environment of breast tumors. Evaluation of CAG repeat length together with ER status could help improve the estimation of the risk of death, with possible implications for the optimization of standard breast cancer treatment and implementation of prevention strategies.
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19
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Sun Z, Prodduturi N, Sun SY, Thompson EA, Kocher JPA. Chromosome X genomic and epigenomic aberrations and clinical implications in breast cancer by base resolution profiling. Epigenomics 2015; 7:1099-110. [PMID: 26039248 DOI: 10.2217/epi.15.43] [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: 12/14/2022] Open
Abstract
AIM Abnormal inactivation or loss of inactivated X chromosome (Xi) is implicated in women's cancer. However, the underlying mechanisms and clinical relevance are little known. MATERIALS & METHODS High-throughput sequencing was conducted on breast cancer cell lines for copy number, RNA expression and 5'-methylcytosine in ChrX. The results were examined in primary breast tumors. RESULTS & CONCLUSION Breast cancer cells demonstrated reduced or total loss of hemimethylation. Most cell lines lost part or one of X chromosomes. Cell lines without ChrX loss were more active in gene expression. DNA methylation was corroborated with Xi control lincRNA XIST. Similar transcriptome and DNA methylation changes were observed in primary breast cancer datasets with clinical phenotype associations. Dramatic genomic and epigenomic changes in ChrX may be used for potential diagnostic or prognostic markers in breast cancer.
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Affiliation(s)
- Zhifu Sun
- Department of Health Sciences Research, Division of Biomedical Statistics & Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Naresh Prodduturi
- Department of Health Sciences Research, Division of Biomedical Statistics & Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Susan Y Sun
- Medical School, University of Minnesota, Minneapolis, MN 55455, USA
| | - E Aubrey Thompson
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Jean-Pierre A Kocher
- Department of Health Sciences Research, Division of Biomedical Statistics & Informatics, Mayo Clinic, Rochester, MN 55905, USA
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Abstract
We describe the trajectory of the human sex ratio from conception to birth by analyzing data from (i) 3- to 6-d-old embryos, (ii) induced abortions, (iii) chorionic villus sampling, (iv) amniocentesis, and (v) fetal deaths and live births. Our dataset is the most comprehensive and largest ever assembled to estimate the sex ratio at conception and the sex ratio trajectory and is the first, to our knowledge, to include all of these types of data. Our estimate of the sex ratio at conception is 0.5 (proportion male), which contradicts the common claim that the sex ratio at conception is male-biased. The sex ratio among abnormal embryos is male-biased, and the sex ratio among normal embryos is female-biased. These biases are associated with the abnormal/normal state of the sex chromosomes and of chromosomes 15 and 17. The sex ratio may decrease in the first week or so after conception (due to excess male mortality); it then increases for at least 10-15 wk (due to excess female mortality), levels off after ∼20 wk, and declines slowly from 28 to 35 wk (due to excess male mortality). Total female mortality during pregnancy exceeds total male mortality. The unbiased sex ratio at conception, the increase in the sex ratio during the first trimester, and total mortality during pregnancy being greater for females are fundamental insights into early human development.
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21
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Richard JLC, Ogawa Y. Understanding the Complex Circuitry of lncRNAs at the X-inactivation Center and Its Implications in Disease Conditions. Curr Top Microbiol Immunol 2015; 394:1-27. [PMID: 25982976 DOI: 10.1007/82_2015_443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Balanced gene expression is a high priority in order to maintain optimal functioning since alterations and variations could result in acute consequences. X chromosome inactivation (X-inactivation) is one such strategy utilized by mammalian species to silence the extra X chromosome in females to uphold a similar level of expression between the two sexes. A functionally versatile class of molecules called long noncoding RNA (lncRNA) has emerged as key regulators of gene expression and plays important roles during development. An lncRNA that is indispensable for X-inactivation is X-inactive specific transcript (Xist), which induces a repressive epigenetic landscape and creates the inactive X chromosome (Xi). With recent advents in the field of X-inactivation, novel positive and negative lncRNA regulators of Xist such as Jpx and Tsix, respectively, have broadened the regulatory network of X-inactivation. Xist expression failure or dysregulation has been implicated in producing developmental anomalies and disease states. Subsequently, reactivation of the Xi at a later stage of development has also been associated with certain tumors. With the recent influx of information about lncRNA biology and advancements in methods to probe lncRNA, we can now attempt to understand this complex network of Xist regulation in development and disease. It has become clear that the presence of an extra set of genes could be fatal for the organism. Only by understanding the precise ways in which lncRNAs function can treatments be developed to bring aberrations under control. This chapter summarizes our current understanding and knowledge with regard to how lncRNAs are orchestrated at the X-inactivation center (Xic), with a special focus on how genetic diseases come about as a consequence of lncRNA dysregulation.
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Affiliation(s)
- John Lalith Charles Richard
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Yuya Ogawa
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
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22
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High-resolution chromosomal microarray analysis of early-stage human embryonic stem cells reveals an association between X chromosome instability and skewed X inactivation. Cell Biosci 2014; 4:74. [PMID: 25506417 PMCID: PMC4265433 DOI: 10.1186/2045-3701-4-74] [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: 09/02/2014] [Accepted: 11/17/2014] [Indexed: 01/14/2023] Open
Abstract
X chromosome inactivation (XCI) is a dosage compensation mechanism that silences the majority of genes on one X chromosome in each female cell via a random process. Skewed XCI is relevant to many diseases, but the mechanism leading to it remains unclear. Human embryonic stem cells (hESCs) derived from the inner cell mass (ICM) of blastocyst-stage embryos have provided an excellent model system for understanding XCI initiation and maintenance. Here, we derived hESC lines with random or skewed XCI patterns from poor-quality embryos and investigated the genome-wide copy number variation (CNV) and loss of heterozygosity (LOH) patterns at the early passages of these two groups of hESC lines. It was found that the average size of CNVs on the X chromosomes in the skewed group is twice as much as that in the random group. Moreover, the LOH regions of the skewed group covered the gene locus of either XIST or XACT, which are master long non-coding RNA (lncRNA) effectors of XCI in human pluripotent stem cells. In conclusion, our work has established an experimentally tractable hESC model for study of skewed XCI and revealed an association between X chromosome instability and skewed XCI.
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23
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The CAG repeat polymorphism of the androgen receptor gene and breast cancer. Open Life Sci 2014. [DOI: 10.2478/s11535-014-0325-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
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24
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Wang J, Yu R, Shete S. X-chromosome genetic association test accounting for X-inactivation, skewed X-inactivation, and escape from X-inactivation. Genet Epidemiol 2014; 38:483-93. [PMID: 25043884 PMCID: PMC4127090 DOI: 10.1002/gepi.21814] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/06/2014] [Accepted: 04/17/2014] [Indexed: 11/07/2022]
Abstract
X-chromosome inactivation (XCI) is the process in which one of the two copies of the X-chromosome in females is randomly inactivated to achieve the dosage compensation of X-linked genes between males and females. That is, 50% of the cells have one allele inactive and the other 50% of the cells have the other allele inactive. However, studies have shown that skewed or nonrandom XCI is a biological plausibility wherein more than 75% of cells have the same allele inactive. Also, some of the X-chromosome genes escape XCI, i.e., both alleles are active in all cells. Current statistical tests for X-chromosome association studies can either account for random XCI (e.g., Clayton's approach) or escape from XCI (e.g., PLINK software). Because the true XCI process is unknown and differs across different regions on the X-chromosome, we proposed a unified approach of maximizing likelihood ratio over all biological possibilities: random XCI, skewed XCI, and escape from XCI. A permutation-based procedure was developed to assess the significance of the approach. We conducted simulation studies to compare the performance of the proposed approach with Clayton's approach and PLINK regression. The results showed that the proposed approach has higher powers in the scenarios where XCI is skewed while losing some power in scenarios where XCI is random or XCI is escaped, with well-controlled type I errors. We also applied the approach to the X-chromosomal genetic association study of head and neck cancer.
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Affiliation(s)
- Jian Wang
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, U.S.A
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, U.S.A
| | - Robert Yu
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, U.S.A
| | - Sanjay Shete
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, U.S.A
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, U.S.A
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Sex-biased chromatin and regulatory cross-talk between sex chromosomes, autosomes, and mitochondria. Biol Sex Differ 2014; 5:2. [PMID: 24422881 PMCID: PMC3907150 DOI: 10.1186/2042-6410-5-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/29/2013] [Indexed: 02/07/2023] Open
Abstract
Several autoimmune and neurological diseases exhibit a sex bias, but discerning the causes and mechanisms of these biases has been challenging. Sex differences begin to manifest themselves in early embryonic development, and gonadal differentiation further bifurcates the male and female phenotypes. Even at this early stage, however, there is evidence that males and females respond to environmental stimuli differently, and the divergent phenotypic responses may have consequences later in life. The effect of prenatal nutrient restriction illustrates this point, as adult women exposed to prenatal restrictions exhibited increased risk factors of cardiovascular disease, while men exposed to the same condition did not. Recent research has examined the roles of sex-specific genes, hormones, chromosomes, and the interactions among them in mediating sex-biased phenotypes. Such research has identified testosterone, for example, as a possible protective agent against autoimmune disorders and an XX chromosome complement as a susceptibility factor in murine models of lupus and multiple sclerosis. Sex-biased chromatin is an additional and likely important component. Research suggesting a role for X and Y chromosome heterochromatin in regulating epigenetic states of autosomes has highlighted unorthodox mechanisms of gene regulation. The crosstalk between the Y chromosomes and autosomes may be further mediated by the mitochondria. The organelles have solely maternal transmission and exert differential effects on males and females. Altogether, research supports the notion that the interaction between sex-biased elements might exert novel regulatory functions in the genome and contribute to sex-specific susceptibilities to autoimmune and neurological diseases.
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26
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Li G, Zhang Z, Jin T, Liang H, Tu Y, Gong L, Chen Z, Gao G. High frequency of the X-chromosome inactivation in young female patients with high-grade glioma. Diagn Pathol 2013; 8:101. [PMID: 23782947 PMCID: PMC3744161 DOI: 10.1186/1746-1596-8-101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/09/2013] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gliomas are common tumors and high-grade ones account for 62% of primary malignant brain tumors. Though current evidence have suggested that inherited risks play a role in glioma susceptibility, it was conveyed that glioma was such a complex disease, and the direct genetic contribution to glioma risk factors and its relation to other factors should be discussed more deeply. X-chromosome inactivation (XCI) is the mechanism by which gene dosage equivalence is achieved between female mammals with two X chromosomes and male mammals with a single X chromosome. As skewed XCI has been linked to development of some solid tumors, including ovarian, breast, and pulmonary and esophageal carcinomas, it is challenging to elucidate the relation of skewed XCI to high-grade gliomas development. OBJECTIVE The present study aimed to determine the general concordance between XCI pattern in blood cells and brain tissues, and SXCI frequencies in female patients with high-grade glioma compared to healthy controls. METHODS 1,103 Chinese females without a detectable tumor and 173 female high-grade glioma patients, were detected in the study. Normal brain tissues surrounding the lesions in gliomas were obtained from 49 patients among the 173 ones, with the microdissection using a laser microdissection microscope Genomic DNA was extracted from the peripheral blood cells and the normal brain tissues from the subjects. Exon 1 of androgen receptor (AR) gene was amplified, and its products of different alleles were resolved on denaturing polyacrylamide gels and visualized after silver staining. The corrected ratios (CR) of the products before and after HpaII digestion were calculated. RESULTS Occurrence of SXCI was detected in both the patients and controls at similar frequencies. However, the phenomenon, as defined as CR ≥ 3, was more frequent in the patients aging ≤ 40 (23.6%) compared to the corresponding reference group (5.1%, P <0.0001). When CR ≥ 10 was adopted, the frequencies were 5.5% and 1.6%, respectively. Their difference did not attain statistical significance (P=0.10). When detected, both blood cells and brain tissue were compared after determination of a high concordance of XCI between blood cells and brain tissue collected from the same individuals (n=48, r =0.57, P <0.01). CONCLUSIONS The data from the current study demonstrated that SXCI may be a predisposing factor for development of high-grade glioma in young female patients and further study will verify its suitability as a biomarker to assess susceptibility of young female patients to high-grade glioma. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1935066233982578.
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Affiliation(s)
- Gang Li
- Department of Neurosurgery, Tangdu hospital, the Fourth Military Medical University, 710038 Xi'an, China. che
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Li G, Jin T, Liang H, Tu Y, Zhang W, Gong L, Su Q, Gao G. Skewed X-chromosome inactivation in patients with esophageal carcinoma. Diagn Pathol 2013; 8:55. [PMID: 23556484 PMCID: PMC3640911 DOI: 10.1186/1746-1596-8-55] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 04/01/2013] [Indexed: 11/15/2022] Open
Abstract
Abstract Skewed X-chromosome inactivation (SXCI) was found in some apparently healthy females mainly from Western countries. It has been linked to development of ovarian, breast and pulmonary carcinomas. The present study aimed to observe the SXCI frequencies in apparently healthy Chinese females and patients with esophageal carcinoma. DNA was extracted from the peripheral blood cells from 401 Chinese females without a detectable tumor and 143 female patients with esophageal carcinoma. Exon 1 of androgen receptor (AR) gene was amplified, and the products of different CAG alleles were resolved on denaturing polyacrylamide gels and visualized after silver staining. The corrected ratios (CR) of the products before and after HpaII digestion were calculated. As to the healthy females, when CR ≥ 3 was used as a criterion, SXCI was found in two (4.3%) of the 46 neonates, 13 (7.8%) of the 166 younger adults (16–50 years) and 37 (25.7%) of the 144 elderly females (51–96 years), with the frequency higher in the elderly subjects than in the two former groups (P < 0.05). When a more stringent criterion (CR ≥ 10) was used, SXCI was found in one (2.2%), two (1.2%) and 16 (11.1%) of the subjects in the three age groups, respectively, itsfrequency being higher in the elderly than in the younger age groups (P < 0.05). Occurrence of SXCI was detected in both the patients and controls at similar frequencies. However, the phenomenon, as defined as CR ≥ 3, was more frequent in the patients aging <40 years (35.7%) compared to the corresponding reference group (7.6%, P = 0.006). When CR ≥ 10 was adopted, the frequencies were 7.1% and 1.2%, respectively. Their difference did not attain statistical significance (P = 0. 217). SXCI also occurs in apparently healthy Chinese females, and is associated with age. It may be considered as a predisposing factor for the early development of esophageal carcinoma. Virtual slides The virtual slide(s) for this article can be found here http://www.diagnosticpathology.diagnomx.eu/vs/1542364337927656
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Affiliation(s)
- Gang Li
- Department of Neurosurgery, Tangdu Hospital, the Fourth Military Medical University, Xi'an, China
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Zheng J, Deng J, Jiang L, Yang L, You Y, Hu M, Li N, Wu H, Li W, Li H, Lu J, Zhou Y. Heterozygous genetic variations of FOXP3 in Xp11.23 elevate breast cancer risk in Chinese population via skewed X-chromosome inactivation. Hum Mutat 2013; 34:619-28. [PMID: 23378296 DOI: 10.1002/humu.22284] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 01/22/2013] [Indexed: 01/21/2023]
Abstract
FOXP3 (forkhead box P3: also known as IPEX, XPID) is not only a hallmark of immunosuppressive regulatory T cells (Tregs), but also an X-linked breast cancer suppressor gene expressed in tumor cells. A two-stage investigation was conducted in individuals from northern, southern and eastern China. Individuals carrying a FOXP3 rs2294021CT genotype showed about 1.5-fold increased risk of breast cancer compared with TT carriers. In a related biochemical assay, the rs2294021C allele was found to significantly enhance transcription activity, leading to higher mRNA levels of FOXP3 compared with T allele. Moreover, the number of Tregs and its corresponding interleukin-10 (IL-10) secretion were elevated whereas the proliferation of antitumor T cells was decreased in the C-allele carriers. The breast cancer oncogenes Her-2/ErbB2 and Skp2 were also found to be significantly inhibited in C-allele carriers. Moreover, skewed X-chromosome inactivation (SXCI) analysis showed that rs2294021CT carriers with SXCI showed higher risk than the homozygous carriers and CT carriers without SXCI, suggesting a possible interaction between the rs2294021CT genotype and SXCI. Taken together, these findings indicate that the rs2294021CT genotype may increase an individual's susceptibility to breast cancer by breaking the balance between Treg-mediated immune tolerance and FOXP3-controlled tumor-suppressive effect.
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Affiliation(s)
- Jian Zheng
- Soochow University Laboratory of Cancer Molecular Genetics, Medical College of Soochow University, Suzhou, China
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Microsatellites in the estrogen receptor (ESR1, ESR2) and androgen receptor (AR) genes and breast cancer risk in African American and Nigerian women. PLoS One 2012; 7:e40494. [PMID: 22792352 PMCID: PMC3394707 DOI: 10.1371/journal.pone.0040494] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/08/2012] [Indexed: 01/02/2023] Open
Abstract
Genetic variants in hormone receptor genes may be crucial predisposing factors for breast cancer, and microsatellites in the estrogen receptor (ESR1, ESR2) and androgen receptor (AR) genes have been suggested to play a role. We studied 258 African-American (AA) women with breast cancer and 259 hospital-based controls, as well as 349 Nigerian (NG) female breast cancer patients and 296 community controls. Three microsatellites, ESR1_TA, ESR2_CA and AR_CAG, in the ESR1, ESR2 and AR genes, respectively, were genotyped. Their repeat lengths were then analyzed as continuous and dichotomous variables. Analyses of continuous variables showed no association with breast cancer risk in either AA or NG at ESR1_TA; AA cases had shorter repeats in the long allele of ESR2_CA than AA controls (Mann-Whitney P= 0.036; logistic regression P = 0.04, OR= 0.91, 95% CI 0.83-1.00), whereas NG patients had longer repeats in the short allele than NG controls (Mann-Whitney P= 0.0018; logistic regression P= 0.04, OR= 1.06, 95% CI 1.00-1.11); and AA cases carried longer repeats in the short allele of AR_CAG than AA controls (Mann-Whitney P= 0.038; logistic regression P = 0.03, OR= 1.08, 95% CI 1.01-1.15). When allele sizes were categorized as dichotomous variables, we discovered that women with two long alleles of ESR2_CA had increased risk of breast cancer (OR = 1.38, 95% CI 1.10-1.74; P = 0.006). This is the first study to investigate these three microsatellites in hormonal receptor genes in relation to breast cancer risk in an indigenous African population. After adjusting for multiple-testing, our findings suggest that ESR2_CA is associated with breast cancer risk in Nigerian women, whereas ESR1_TA and AR_CAG seem to have no association with the disease among African American or Nigerian women.
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Abstract
Cancer cells silence autosomal tumor suppressor genes by Knudson's two-hit mechanism in which loss-of-function mutations and then loss of heterozygosity occur at the tumor suppressor gene loci. However, the identification of X-linked tumor suppressor genes has challenged the traditional theory of 'two-hit inactivation' in tumor suppressor genes, introducing the novel concept that a single genetic hit can cause loss of tumor suppressor function. The mechanism through which these genes are silenced in human cancer is unclear, but elucidating the details will greatly enhance our understanding of the pathogenesis of human cancer. Here, we review the identification of X-linked tumor suppressor genes and discuss the potential mechanisms of their inactivation. In addition, we also discuss how the identification of X-linked tumor suppressor genes can potentially lead to new approaches in cancer therapy.
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Affiliation(s)
- Runhua Liu
- Division of Immunotherapy, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA
- Department of Genetics, School of Medicine, University of Alabama at Birmingham and Comprehensive Cancer Center, Birmingham, AL, USA
| | - Mandy Kain
- Division of Immunotherapy, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Lizhong Wang
- Division of Immunotherapy, Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA
- Department of Genetics, School of Medicine, University of Alabama at Birmingham and Comprehensive Cancer Center, Birmingham, AL, USA
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Skewed X inactivation and survival: a 13-year follow-up study of elderly twins and singletons. Eur J Hum Genet 2011; 20:361-4. [PMID: 22146940 DOI: 10.1038/ejhg.2011.215] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In mammalian females, one of the two X chromosomes is inactivated in early embryonic life. Females are therefore mosaics for two cell populations, one with the maternal and one with the paternal X as the active X chromosome. A skewed X inactivation is a marked deviation from a 50:50 ratio. In populations of women past 55-60 years of age, an increased degree of skewing (DS) is found. Here the association between age-related skewing and mortality is analyzed in a 13-year follow-up study of 500 women from three cohorts (73-100 years of age at intake). Women with low DS had significantly higher mortality than the majority of women who had a more skewed DS (hazard ratio: 1.30; 95% CI: 1.04-1.64). The association between X inactivation and mortality was replicated in dizygotic twin pairs for which the co-twin with the lowest DS also had a statistically significant tendency to die first in the twin pairs with the highest intra-pair differences in DS (proportion: 0.71; 95% CI: 0.52-0.86). Both results suggest that lower DS is associated with higher mortality. We therefore propose that age-related skewing may be partly due to a population selection with lower mortality among those with higher DS.
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Sakoda LC, Blackston CR, Doherty JA, Ray RM, Lin MG, Gao DL, Stalsberg H, Feng Z, Thomas DB, Chen C. Selected estrogen receptor 1 and androgen receptor gene polymorphisms in relation to risk of breast cancer and fibrocystic breast conditions among Chinese women. Cancer Epidemiol 2010; 35:48-55. [PMID: 20846920 DOI: 10.1016/j.canep.2010.08.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 08/12/2010] [Accepted: 08/14/2010] [Indexed: 11/16/2022]
Abstract
BACKGROUND Polymorphisms in sex hormone receptor-encoding genes may alter the activity of sex hormone receptors and thereby affect susceptibility to breast cancer and related outcomes. METHODS In a case-control study of women from Shanghai, China, we examined the risk of breast cancer and fibrocystic breast conditions associated with the ESR1 PvuII (rs2234693) and XbaI (rs9340799) and AR CAG repeat ((CAG)(n)) and GGC repeat ((GGC)(n)) polymorphisms among 614 women with breast cancer, 467 women with fibrocystic conditions, and 879 women without breast disease. We also evaluated whether risk differed by the presence/absence of proliferative changes (in the extratumoral epithelium or fibrocystic lesion), menopausal status, or body mass index (BMI). Age-adjusted odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated using logistic regression. RESULTS Only associations with AR (CAG)(n) and (GGC)(n) genotypes were detected. Allocating AR (CAG)(n) genotypes into six categories, with the (CAG)(22-24)/(CAG)(22-24) genotype category designated as the reference group, the (CAG)(>24)/(CAG)(>24) genotype category was associated with an increased risk of fibrocystic breast conditions (OR, 1.8; 95% CI, 1.1-3.0). Relative to the AR (GGC)(17)/(GGC)(17) genotype, the (GGC)(17)/(GGC)(14) genotype was associated with elevated risks of incident breast cancer (OR, 2.6; 95% CI, 1.3-5.4) and fibrocystic conditions (OR, 2.3; 95% CI, 1.1-4.5). Results did not differ according to proliferation status, menopausal status, or BMI. CONCLUSION Although these data lend support for a link between AR variation and breast disease development, given the low frequency of the putative risk-conferring genotypes and other constraints, further confirmation of our results is needed.
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Affiliation(s)
- Lori C Sakoda
- Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
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Liu W, Sun X. Skewed X chromosome inactivation in diploid and triploid female human embryonic stem cells. Hum Reprod 2009; 24:1834-43. [DOI: 10.1093/humrep/dep126] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lose F, Duffy DL, Kay GF, Kedda MA, Spurdle AB. Skewed X chromosome inactivation and breast and ovarian cancer status: evidence for X-linked modifiers of BRCA1. J Natl Cancer Inst 2008; 100:1519-29. [PMID: 18957670 DOI: 10.1093/jnci/djn345] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND X chromosome inactivation, which silences gene expression from one of the two X chromosomes in females, is usually random. Skewed X inactivation has been implicated in both the expression and the suppression of X-linked disease phenotypes and has been reported to occur more frequently in breast and ovarian cancer patients, including BRCA1 or BRCA2 mutation carriers, than in control subjects. METHODS We assessed the pattern of X chromosome inactivation using methylation-specific polymerase chain reaction amplification of the exon 1 microsatellite region of the X-linked androgen receptor (AR) gene in DNA from blood samples obtained from control subjects without a personal history of breast or ovarian cancer (n = 735), ovarian cancer patients (n = 313), familial breast cancer patients who did not carry mutations in BRCA1 or BRCA2 (n = 235), and affected and unaffected carriers of mutations in BRCA1 (n = 260) or BRCA2 (n = 63). We defined the pattern of X chromosome inactivation as skewed when the same X chromosome was active in at least 90% of cells. The association between skewed X inactivation and disease and/or BRCA mutation status was assessed by logistic regression analysis. The association between skewed X inactivation and age at cancer diagnosis was assessed by Cox proportional hazards regression analysis. All statistical tests were two-sided. RESULTS The age-adjusted frequency of skewed X inactivation was not statistically significantly higher in ovarian cancer or familial breast cancer case subjects compared with control subjects. Skewed X inactivation was higher in BRCA1 mutation carriers than in control subjects (odds ratio [OR] = 2.7, 95% confidence interval [CI] = 1.1 to 6.2; P = .02), particularly among unaffected women (OR = 6.1, 95% CI = 1.5 to 31.8; P = .005). Among BRCA1 mutation carriers, those with skewed X inactivation were older at diagnosis of breast or ovarian cancer than those without skewed X inactivation (hazard ratio [HR] of breast or ovarian cancer = 0.37, 95% CI = 0.14 to 0.95; P = .04). Among BRCA2 mutation carriers, skewed X inactivation also occurred more frequently in unaffected carriers than in those diagnosed with breast or ovarian cancer (OR = 5.2, 95% CI = 0.5 to 28.9; P = .08) and was associated with delayed age at onset (HR = 0.59, 95% CI = 0.37 to 0.94; P = .03). CONCLUSIONS Skewed X inactivation occurs at an increased frequency in BRCA1 (and possibly BRCA2) mutation carriers compared with control subjects and is associated with a statistically significant increase in age at diagnosis of breast and ovarian cancer.
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Affiliation(s)
- Felicity Lose
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, Herston, Brisbane, Queensland, Australia
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Knudsen G, Riegert-Johnson D, Meling G, Boardman L, Ørstavik K. Lack of Association between Skewing of X-Chromosome Inactivation in Blood Cells and Colorectal Cancer. Int J Biol Markers 2008; 23:127-8. [DOI: 10.1177/172460080802300211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- G.P.S. Knudsen
- Faculty Division Rikshospitalet, University of Oslo, Oslo - Norway
| | | | - G.I. Meling
- Department of Surgery, Akershus University Hospital, Akershus
- Institute of Forensic Medicine, University of Oslo, Oslo
| | - L.A. Boardman
- Division of Gastroenterology, Mayo Clinic College of Medicine, Rochester - USA
| | - K.H. Ørstavik
- Faculty Division Rikshospitalet, University of Oslo, Oslo - Norway
- Department of Medical Genetics, Rikshospitalet University Hospital, Oslo - Norway
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Lose F, Arnold J, Young DB, Brown CJ, Mann GJ, Pupo GM, Khanna KK, Chenevix-Trench G, Spurdle AB. BCoR-L1 variation and breast cancer. Breast Cancer Res 2008; 9:R54. [PMID: 17697391 PMCID: PMC2206730 DOI: 10.1186/bcr1759] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 07/23/2007] [Accepted: 08/16/2007] [Indexed: 11/10/2022] Open
Abstract
Introduction BRCA1 is involved in numerous essential processes in the cell, and the effects of BRCA1 dysfunction in breast cancer carcinogenesis are well described. Many of the breast cancer susceptibility genes such as BRCA2, p53, ATM, CHEK2, and BRIP1 encode proteins that interact with BRCA1. BCL6 corepressor-like 1 (BCoR-L1) is a newly described BRCA1-interacting protein that displays high homology to several proteins known to be involved in the fundamental processes of DNA damage repair and transcription regulation. BCoR-L1 has been shown to play a role in transcription corepression, and expression of the X-linked BCoR-L1 gene has been reported to be dysregulated in breast cancer subjects. BCoR-L1 is located on the X chromosome and is subject to X inactivation. Methods We performed mutation analysis of 38 BRCA1/2 mutation-negative breast cancer families with male breast cancer, prostate cancer, and/or haplotype sharing around BCoR-L1 to determine whether there is a role for BCoR-L1 as a high-risk breast cancer predisposition gene. In addition, we conducted quantitative real-time PCR (qRT-PCR) on lymphoblastoid cell lines (LCLs) from the index cases from these families and a number of cancer cell lines to assess the role of BCoR-L1 dysregulation in cancer and cancer families. Results Very little variation was detected in the coding region, and qRT-PCR analysis revealed that BCoR-L1 expression is highly variable in cancer-free subjects, high-risk breast cancer patients, and cancer cell lines. We also report the investigation of a new expression control, DIDO1 (death inducer-obliterator 1), that is superior to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and UBC (ubiquitin C) for analysis of expression in LCLs. Conclusion Our results suggest that BCoR-L1 expression does not play a large role in predisposition to familial breast cancer.
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Affiliation(s)
- Felicity Lose
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
- School of Medicine, Central Clinical Division, University of Queensland, Royal Brisbane Hospital, Corner Butterfield Street and Bowen Bridge Road, Brisbane, Queensland, Australia, 4029
| | - Jeremy Arnold
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
| | - David B Young
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
| | - Carolyn J Brown
- Department of Medical Genetics, Molecular Epigenetics Group, University of British Columbia, 2329 West Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Graham J Mann
- Westmead Institute for Cancer Research, University of Sydney at Westmead Millennium Institute, Westmead Hospital, Darcy Road, Westmead, New South Wales, Australia, 2145
| | - Gulietta M Pupo
- Westmead Institute for Cancer Research, University of Sydney at Westmead Millennium Institute, Westmead Hospital, Darcy Road, Westmead, New South Wales, Australia, 2145
| | | | - Kum Kum Khanna
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
| | - Georgia Chenevix-Trench
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
| | - Amanda B Spurdle
- Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006
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Rocha RO, Billerbeck AEC, Pinto EM, Melo KFS, Lin CJ, Longui CA, Mendonca BB, Bachega TASS. The degree of external genitalia virilization in girls with 21-hydroxylase deficiency appears to be influenced by the CAG repeats in the androgen receptor gene. Clin Endocrinol (Oxf) 2008; 68:226-32. [PMID: 17803691 DOI: 10.1111/j.1365-2265.2007.03023.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Women with 21-hydroxylase deficiency present much variability in external genitalia virilization, even among those with similar impairments of 21-hydroxylase (21OH) activity. OBJECTIVE To evaluate if the number of CAG (nCAG) repeats of the androgen receptor gene influences the degree of external genitalia virilization in women with CYP21A2 mutations, grouped according to impairment of 21OH activity. PATIENTS The nCAG was determined in 106 congenital adrenal hyperplasia (CAH) patients and in 302 controls. The patients were divided, according to their CYP21A2 genotypes, into Groups A and B, which confer total and severe impairment of 21OH activity, respectively. METHODS The inactivation pattern of the X-chromosome was studied through genomic DNA digestion with Hpa II. The CAG repeat region was amplified by polymerase chain reaction (PCR) and analysed by GeneScan. RESULTS The nCAG and the frequency of severe skewed X-inactivation did not differ between normal women and patients. The nCAG median in genotype A was 20.7 (IQR 2.3) for Prader I + II, 22.5 (3.6) for Prader III and 21 (2.9) for Prader IV + V (P < 0.05 for Prader III and Prader IV + V). The nCAG median in genotype B was 21.3 (1.1) for Prader I + II, 20.5 (2.9) for Prader III and 22 (2.8) for Prader IV + V (P > 0.05). A significant difference was found regarding the nCAG median in patients presenting Prader III from genotypes A and B. CONCLUSIONS We observed great variability in the degree of external genitalia virilization in both CYP21A2 genotypes, and we showed that the CAG repeats of the androgen receptor gene influences this phenotypic variability.
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Affiliation(s)
- Rosana O Rocha
- Laboratório de Hormônios e Genética Molecular-LIM/42, Unidade de Endocrinologia do Desenvolvimento, Disciplina de Endocrinologia, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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Abstract
X chromosome inactivation involves a random choice to silence either X chromosome early in mammalian female development. Once silenced the inactive X is stably inherited through subsequent somatic cell divisions, and thus, females are generally mosaics, having a mixture of cells with one or the other parental X active. While in most females the number of cells with either X being active is roughly equal, skewing of X chromosome inactivation is observed in a percentage of women. In this issue of the JCI, Bolduc and colleagues address whether skewing of X chromosome inactivation in humans is influenced by an X-linked locus that can alter this initial random inactivation (see the related article beginning on page 333). Their data indicate that most of the skewing observed in humans results from secondary events rather than being due to an inherited tendency to inactivate a particular X chromosome.
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Affiliation(s)
- Jakub Minks
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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Tsezou A, Tzetis M, Gennatas C, Giannatou E, Pampanos A, Malamis G, Kanavakis E, Kitsiou S. Association of repeat polymorphisms in the estrogen receptors alpha, beta (ESR1, ESR2) and androgen receptor (AR) genes with the occurrence of breast cancer. Breast 2007; 17:159-66. [PMID: 17904846 DOI: 10.1016/j.breast.2007.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 08/10/2007] [Accepted: 08/20/2007] [Indexed: 10/22/2022] Open
Abstract
Genetic variation in genes involved in estrogen biosynthesis, metabolism and signal transduction have been suggested to play a role in breast cancer. To determine the possible contribution of genetic variation in the ESR1 (ER-alpha), ESR2 (ER-beta) and AR genes in breast cancer risk the -1174(TA)(7-27), c. 1092+3607(CA)(10-26) and c. 172(CAG)(6-40) repeat variants were studied in a case-control study of 79 women with sporadic breast cancer and 155 controls. No significant difference was observed in the frequency distribution of -1174(TA)(7-27) in the ESR1 gene between patients and controls, while a significant difference was observed for repeat polymorphisms c. 1092+3607(CA)(10-26) in the ESR2 gene and c. 172(CAG)(6-40) in the AR gene (p0.0001). A significantly decreased odds ratio (OR) for breast cancer risk was observed in individuals having the LL and the SL genotypes for both the ESR2 (OR=0.010, 95% CI 0.003-0.036, p<0.001; OR=0.013, 95% CI 0.004-0.040, p<0.0001, respectively) and the AR gene (OR=0.040, 95% CI 0.011-0.138, p<0.0001; OR=0.189, 95% CI 0.10-0.359, p<0.0001, respectively), compared to SS genotype. The protective effect of these genotypes remained evident even after adjustment for various risk factors (BMI, age, age at menarche and menopause, family history). In conclusion, an association for breast cancer risk between short (SS) alleles for the repeat variants of the ESR2 and AR genes was found in women of Greek descent.
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Affiliation(s)
- A Tsezou
- Laboratory of Cytogenetics and Molecular Genetics, Medical School, University of Thessalia, University Hospital of Larissa, Larissa, Greece
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Thakur A, Rahman KW, Wu J, Bollig A, Biliran H, Lin X, Nassar H, Grignon DJ, Sarkar FH, Liao JD. Aberrant expression of X-linked genes RbAp46, Rsk4, and Cldn2 in breast cancer. Mol Cancer Res 2007; 5:171-81. [PMID: 17314274 DOI: 10.1158/1541-7786.mcr-06-0071] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The consequence of activation status or gain/loss of an X-chromosome in terms of the expression of tumor suppressor genes or oncogenes in breast cancer has not been clearly addressed. In this study, we investigated the activation status of the X-chromosomes in a panel of human breast cancer cell lines, human breast carcinoma, and adjacent mammary tissues and a panel of murine mammary epithelial sublines ranging from low to high invasive potentials. Results show that most human breast cancer cell lines were homozygous, but both benign cell lines were heterozygous for highly polymorphic X-loci (IDS and G6PD). On the other hand, 60% of human breast carcinoma cases were heterozygous for either IDS or G6PD markers. Investigation of the activation status of heterozygous cell lines revealed the presence of only one active X-chromosome, whereas most heterozygous human breast carcinoma cases had two active X-chromosomes. Furthermore, we determined whether or not an additional active X-chromosome affects expression levels of tumor suppressor genes and oncogenes. Reverse transcription-PCR data show high expression of putative tumor suppressor genes Rsk4 and RbAp46 in 47% and 79% of breast carcinoma cases, respectively, whereas Cldn2 was down-regulated in 52% of breast cancer cases compared with normal adjacent tissues. Consistent with mRNA expression, immunostaining for these proteins also showed a similar pattern. In conclusion, our data suggest that high expression of RbAp46 is likely to have a role in the development or progression of human breast cancer. The activation status of the X-chromosome may influence the expression levels of X-linked oncogenes or tumor suppressor genes.
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Affiliation(s)
- Archana Thakur
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, 110 East Warren Avenue, Detroit, MI 48201, USA
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Birrell SN, Butler LM, Harris JM, Buchanan G, Tilley WD. Disruption of androgen receptor signaling by synthetic progestins may increase risk of developing breast cancer. FASEB J 2007; 21:2285-93. [PMID: 17413000 DOI: 10.1096/fj.06-7518com] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There is now considerable evidence that using a combination of synthetic progestins and estrogens in hormone replacement therapy (HRT) increases the risk of breast cancer compared with estrogen alone. Furthermore, the World Health Organization has recently cited combination contraceptives, which contain synthetic progestins, as potentially carcinogenic to humans, particularly for increased breast cancer risk. Given the above observations and the current trend toward progestin-only contraception, it is important that we have a comprehensive understanding of how progestins act in the millions of women worldwide who regularly take these medications. While synthetic progestins, such as medroxyprogesterone acetate (MPA), which are currently used in both HRT and oral contraceptives were designed to act exclusively through the progesterone receptor, it is clear from both clinical and experimental settings that their effects may be mediated, in part, by binding to the androgen receptor (AR). Disruption of androgen action by synthetic progestins may have serious deleterious side effects in the breast, where the balance between estrogen signaling and androgen signaling plays a critical role in breast homeostasis. Here, we review the role of androgen signaling in the normal breast and in breast cancer and present new data demonstrating that androgen receptor function can be perturbed by low doses of MPA, similar to doses achieved in serum of women taking HRT. We propose that the observed excess of breast malignancies associated with combined HRT may be explained, in part, by synthetic progestins such as MPA acting as endocrine disruptors to negate the protective effects of androgen signaling in the breast. Understanding the role of androgen signaling in the breast and how this is modulated by synthetic progestins is necessary to determine how combined HRT alters breast cancer risk, and to inform the development of optimal preventive and treatment strategies for this disease.
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Affiliation(s)
- Stephen N Birrell
- Dame Roma Mitchell Cancer Research Laboratories, The University of Adelaide, Hanson Institute, PO Box 14, Rundle Mall, South Australia, 5000, Australia
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42
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Uz E, Dolen I, Al AR, Ozcelik T. Extremely skewed X-chromosome inactivation is increased in pre-eclampsia. Hum Genet 2006; 121:101-5. [PMID: 17115188 DOI: 10.1007/s00439-006-0281-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Accepted: 10/11/2006] [Indexed: 11/25/2022]
Abstract
Pre-eclampsia is a disorder that affects approximately 5% of pregnancies. We tested the hypothesis that skewed X-chromosome inactivation (XCI) could be involved in the pathogenesis of pre-eclampsia. Peripheral blood DNA was obtained from 67 pre-eclampsia patients and 130 control women. Androgen receptor (AR) was analyzed by the HpaII/polymerase chain reaction assay to assess XCI patterns in DNA extracted from peripheral-blood cells. In addition, buccal cells were obtained from seven patients, and the analysis repeated. Extremely skewed XCI was observed in 10 of 46 informative patients (21.74%), and in 2 of 86 informative controls (2.33%, P = 0.0005; chi(2) test). Our findings support a role for the X-chromosome in the pathogenesis of pre-eclampsia in a subgroup of patients.
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Affiliation(s)
- Elif Uz
- Department of Molecular Biology and Genetics, Bilkent University, Bilkent, Ankara 06800, Turkey
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43
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Retornaz F, Paris F, Lumbroso S, Audran F, Tigoulet F, Michelon C, Jeandel C, Sultan C, Blain H. Association between androgen receptor gene polymorphism and bone density in older women using hormone replacement therapy. Maturitas 2006; 55:325-33. [PMID: 16759824 DOI: 10.1016/j.maturitas.2006.04.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 04/25/2006] [Accepted: 04/28/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the relationship between bone mineral density (BMD) and both CAG repeat polymorphism of the androgen receptor (AR) gene and skewed X chromosome inactivation (SI) in postmenopausal women. METHODS BMD was measured by DEXA. Both the number and the X-weighted biallelic mean of the CAG repeats of AR were analysed by PCR, before and after DNA digestion with methylation-sensitive HpaII in 192 healthy Caucasian postmenopausal women. RESULTS The number of CAG repeats ranged from 10 to 34, with a median value of 22. CAG)(n< or =22) and CAG)(n> or =23) alleles were designated as short and long alleles, respectively. In women using hormone replacement therapy (HRT) (n=81), lumbar spine BMD was significantly lower, and femoral neck and total body BMD marginally lower in those with long-long alleles when compared with those with other genotypes. SI (> or =80%) was observed in 24% of the women and was not associated with BMD. In women using HRT, femoral neck BMD was significantly lower, and lumbar spine and total body BMD marginally lower in those whose X-weighted CAG repeat biallelic was greater than 22.59 (median value) when compared to other genotypes. These results were not found in women not using HRT. CONCLUSION In conclusion, our results suggest that BMD may be associated with AR gene polymorphism in postmenopausal women using HRT but not with SI. Further studies are needed to investigate the mechanisms of the interaction between HRT, BMD and AR found in the present study.
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Affiliation(s)
- Fréderique Retornaz
- Department of Internal Medicine and Geriatrics, University Hospital, Montpellier, France
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Helbling-Leclere A, Lenoir GM, Feunteun J. Heterozygote BRCA1 status and skewed chromosome X inactivation. Fam Cancer 2006; 6:153-7. [PMID: 16944269 DOI: 10.1007/s10689-006-9102-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Accepted: 08/02/2006] [Indexed: 10/24/2022]
Abstract
A high frequency of skewed X-chromosome inactivation has been reported in peripheral blood lymphocytes from early onset breast cancer or invasive ovarian cancer patients. Recent findings have shown that breast and ovarian carcinoma cells from BRCA1 mutation carrier women lack the hallmarks of inactive X chromatin structure. These observations suggested that loss of functional BRCA1 in female cells may perturb the process of X inactivation and have lead us to the hypothesis that analysis of skewing could be used as a predictive test for BRCA1 germline mutation in lymphocytes from breast cancer patients. In the present study, we have compared the X inactivation pattern in lymphoblastoid cell lines from 38 females carrying heterozygous BRCA1 mutation to 41 controls. X inactivation analysis was assessed on the polymorphic CAG repeat within the human androgen receptor gene. Our observations rule out an effect of a monoallelic BRCA1 germline mutation on the choice of inactivated chromosome X and therefore the possibility of using analysis of Xi skewing as a predictive test for BRCA1 germline mutation carrier status.
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Affiliation(s)
- Anne Helbling-Leclere
- Genomes et Cancer FRE 2939, Institut Gustave-Roussy, 39 rue Camille-Desmoulins, 94805 Villejuif, France
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Braunstein M, Özçelik T, Bağişlar S, Vakil V, Smith ELP, Dai K, Akyerli CB, Batuman OA. Endothelial progenitor cells display clonal restriction in multiple myeloma. BMC Cancer 2006; 6:161. [PMID: 16790068 PMCID: PMC1557670 DOI: 10.1186/1471-2407-6-161] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 06/22/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In multiple myeloma (MM), increased neoangiogenesis contributes to tumor growth and disease progression. Increased levels of endothelial progenitor cells (EPCs) contribute to neoangiogenesis in MM, and, importantly, covary with disease activity and response to treatment. In order to understand the mechanisms responsible for increased EPC levels and neoangiogenic function in MM, we investigated whether these cells were clonal by determining X-chromosome inactivation (XCI) patterns in female patients by a human androgen receptor assay (HUMARA). In addition, EPCs and bone marrow cells were studied for the presence of clonotypic immunoglobulin heavy-chain (IGH) gene rearrangement, which indicates clonality in B cells; thus, its presence in EPCs would indicate a close genetic link between tumor cells in MM and endothelial cells that provide tumor neovascularization. METHODS A total of twenty-three consecutive patients who had not received chemotherapy were studied. Screening in 18 patients found that 11 displayed allelic AR in peripheral blood mononuclear cells, and these patients were further studied for XCI patterns in EPCs and hair root cells by HUMARA. In 2 patients whose EPCs were clonal by HUMARA, and in an additional 5 new patients, EPCs were studied for IGH gene rearrangement using PCR with family-specific primers for IGH variable genes (VH). RESULTS In 11 patients, analysis of EPCs by HUMARA revealed significant skewing (> or = 77% expression of a single allele) in 64% (n = 7). In 4 of these patients, XCI skewing was extreme (> or = 90% expression of a single allele). In contrast, XCI in hair root cells was random. Furthermore, PCR amplification with VH primers resulted in amplification of the same product in EPCs and bone marrow cells in 71% (n = 5) of 7 patients, while no IGH rearrangement was found in EPCs from healthy controls. In addition, in patients with XCI skewing in EPCs, advanced age was associated with poorer clinical status, unlike patients whose EPCs had random XCI. CONCLUSION Our results suggest that EPCs in at least a substantial subpopulation of MM patients are related to the neoplastic clone and that this is an important mechanism for upregulation of tumor neovascularization in MM.
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Affiliation(s)
- Marc Braunstein
- Division of Hematology/Oncology, Department of Medicine; Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Tayfun Özçelik
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Sevgi Bağişlar
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Varsha Vakil
- Division of Hematology/Oncology, Department of Medicine; Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Eric LP Smith
- Division of Hematology/Oncology, Department of Medicine; Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Kezhi Dai
- Division of Hematology/Oncology, Department of Medicine; Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Cemaliye B Akyerli
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Olcay A Batuman
- Division of Hematology/Oncology, Department of Medicine; Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY, USA
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Bretherick K, Gair J, Robinson WP. The association of skewed X chromosome inactivation with aneuploidy in humans. Cytogenet Genome Res 2005; 111:260-5. [PMID: 16192703 DOI: 10.1159/000086898] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Accepted: 02/22/2005] [Indexed: 01/25/2023] Open
Abstract
Recently, we reported that skewed X chromosome inactivation (XCI) was more common in women who had experienced a trisomic pregnancy as compared to control women. Rather than an overall shift in the distribution of skewing there appears to only be an excess of extreme (= 95%) skewing. Further analysis of our data reveals that the increase in skewed XCI is dependent on which chromosome is involved in the trisomy and how many trisomies the woman has experienced, although sample sizes in each group are small. In this review we discuss limitations of the commonly used assays of XCI, which use measurements of DNA methylation to infer skewing patterns, and review the data based on current knowledge of the causes of XCI skewing. Gonadal mosaicism, premature aging, loss of methylation at some CpGs, and X-linked mutations can all be considered as potential mechanisms explaining both increased risk of trisomy and skewed XCI. While further research is needed to evaluate the role of each of these, the association of trisomy with apparent skewed XCI in the mother offers new opportunities to clarify the risk factors for and causes of the high incidence of aneuploidy in human females.
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Affiliation(s)
- K Bretherick
- Department of Medical Genetics, University of British Columbia, BC Research Institute for Children's and Women's Health, Vancouver, BC, Canada
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47
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Ozbalkan Z, Bagişlar S, Kiraz S, Akyerli CB, Ozer HTE, Yavuz S, Birlik AM, Calgüneri M, Ozçelik T. Skewed X chromosome inactivation in blood cells of women with scleroderma. ACTA ACUST UNITED AC 2005; 52:1564-70. [PMID: 15880831 DOI: 10.1002/art.21026] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Scleroderma (SSc) is an autoimmune disease of unknown etiology. The disease is 3-8 times more frequent in women than in men. The role of X chromosome inactivation (XCI) in the predisposition of women to autoimmunity has been questioned. Until now this has not been illustrated experimentally. This study was undertaken to test the hypothesis that disturbances in XCI mosaicism may be involved in the pathogenesis of the disease in female patients with SSc. METHODS Seventy female SSc patients and 160 female controls were analyzed for the androgen receptor locus by the Hpa II/polymerase chain reaction assay to assess XCI patterns in DNA extracted from peripheral blood cells. Furthermore, skin biopsy samples were obtained from 5 patients whose blood revealed an extremely skewed pattern of XCI, and the analysis repeated. Since microchimerism in SSc was reported, Y chromosome sequences were investigated in all samples. RESULTS Skewed XCI was observed in DNA from peripheral blood cells in 35 of 55 informative patients (64%), as compared with 10 of 124 informative controls (8%) (P < 0.0001). Extreme skewing was present in 27 of the patient group (49%), as compared with only 3 of the controls (2.4%) (P < 0.0001). However, XCI was random in all skin biopsy samples. The potential contribution of microchimerism to the random XCI pattern is highly unlikely based on the medical histories of the patients. CONCLUSION Skewed XCI mosaicism may play a significant role in the pathogenesis of SSc.
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Struewing JP, Pineda MA, Sherman ME, Lissowska J, Brinton LA, Peplonska B, Bardin-Mikolajczak A, Garcia-Closas M. Skewed X chromosome inactivation and early-onset breast cancer. J Med Genet 2005; 43:48-53. [PMID: 15923273 PMCID: PMC1876702 DOI: 10.1136/jmg.2005.033134] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Skewed X chromosome inactivation may be more common in women with epithelial ovarian cancer and early-onset breast cancer. We tested this hypothesis in a group of 235 breast cancer patients and 253 controls (mean age 45.8 years) from a larger population based case control study. METHODS We measured X chromosome inactivation with the AR gene assay in lymphocyte DNA digested with the methylation specific enzyme HpaII. We judged skewness using an adjusted measure (relative to the undigested sample) with a cut point of 75%, and an unadjusted measure where skewed was defined as > 90% of the signal from one allele in the HpaII digested sample. RESULTS There were no significant differences in any of the skewing measures between cases and controls. Using the adjusted skewing measure among pre-menopausal subjects under the age of 50, 14% of cases versus 11% of controls were skewed, OR = 1.2, 95% CI 0.6 to 2.3; using the unadjusted measure, OR = 0.9, 95% CI 0.4 to 2.0. CONCLUSIONS While we cannot rule out a subtle difference of approximately twofold or less, we have failed to find a significant difference in the prevalence of skewed X chromosome inactivation in younger women with breast cancer compared to controls.
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Affiliation(s)
- J P Struewing
- Laboratory of Population Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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Brum IS, Spritzer PM, Paris F, Maturana MA, Audran F, Sultan C. Association between androgen receptor gene CAG repeat polymorphism and plasma testosterone levels in postmenopausal women. ACTA ACUST UNITED AC 2005; 12:135-41. [PMID: 15695110 DOI: 10.1016/j.jsgi.2004.11.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The biologic action of androgens in target cells depends on plasma androgen levels and receptor transcriptional activity. We investigated the relationship between androgen receptor (AR) CAG repeat polymorphism, serum androgen levels, and anthropometric, metabolic, and hormonal variables in 39 postmenopausal women, taking into consideration the patterns of X-chromosome inactivation. METHODS Genomic DNA was extracted from peripheral leukocytes. Polymerase chain reactions (PCRs) were performed to amplify the polymorphic (CAG)n repeat of the human AR gene, which were analyzed with GeneScan software (Applied Biosystems, Foster City, CA). The X-chromosome inactivation analysis was based on the AR gene methylation patterns. RESULTS The mean age of participants was 54.7 years; mean age at menopause was 48 years. The number of CAG repeats ranged from 15 to 30, with a median length of 23. Analysis of X-chromosome inactivation patterns showed 19 cases with a degree of skewing (DS) > or =70% and seven with a DS > or =90%. The X-weighted CAG repeat biallelic mean was significantly lower in individuals with total testosterone (TT) greater than 0.56 ng/mL (group mean) than in the group with TT < or =0.56 (P=.018). No difference was observed between the groups regarding dehydroepiandrosterone sulfate (DHEA-S). Plasma TT was significantly higher in the group with the smaller X-weighted CAG repeat biallelic mean (P=.01). Free androgen index (FAI) was also significantly higher in this group (P=.033). Testosterone levels and FAI were inversely correlated to X-weighted CAG repeat biallelic mean. CONCLUSION Our data indicate an association between testosterone plasma levels and AR CAG repeats in postmenopausal women, and suggest that plasma levels of androgens in postmenopausal women may be related to variants of the AR gene.
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Affiliation(s)
- Ilma Simoni Brum
- Department of Physiology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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Hatakeyama C, Anderson CL, Beever CL, Peñaherrera MS, Brown CJ, Robinson WP. The dynamics of X-inactivation skewing as women age. Clin Genet 2005; 66:327-32. [PMID: 15355435 DOI: 10.1111/j.1399-0004.2004.00310.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Non-random X-chromosome inactivation (XCI) has been associated with X-linked diseases, neoplastic diseases, recurrent pregnancy loss, and trisomy risk. It also occurs more commonly in older female populations. To understand the etiology of non-random XCI and utilize this assay appropriately in clinical research and practice, the age-related alteration in XCI patterns in normal females needs to be clearly defined. In the present study, we evaluated the XCI status in 350 unselected women aged 0-88 years with unknown history of genetic disorders or abnormal pregnancies. DNA samples were extracted from peripheral blood and analyzed by a methylation-based assay at the androgen receptor locus. A weak but significant positive correlation was observed between age and degree of skewing in XCI over the whole age range (r = 0.23, p < 0.0001), and skewing values become non-normally distributed at older ages. However, the increase in skewed XCI appears to be more pronounced after age 30 than at younger ages. This trend supports the model of increased skewing with age as a consequence of hematopoietic stem cell senescence. An alternative possibility is that there is allele-specific loss of methylation with time that results in the appearance of increased XCI skewing using a methylation-based assay.
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Affiliation(s)
- C Hatakeyama
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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