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Cellular Senescence in Normal Mammary Gland and Breast Cancer. Implications for Cancer Therapy. Genes (Basel) 2022; 13:genes13060994. [PMID: 35741756 PMCID: PMC9223240 DOI: 10.3390/genes13060994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 01/10/2023] Open
Abstract
Cellular senescence (CS) is a major homeostatic biological process, which plays a key role in normal tissue development and provides protection from stressful cell insults. The role of CS in mammary-gland development and breast cancer is not well understood. While there is a lack of experimental data on the role of CS in the development of the pre-pubertal mammary gland, there is evidence for a biphasic senescence response in adult normal-mammary-epithelial cells, where the bypass of the first senescence barrier (M0) seems to be a key step in the development of premalignant lesions, with genetic abnormalities that resemble in situ breast carcinoma. Further, there is accumulating evidence for the role of cellular senescence in breast-cancer response, regarding treatment and patient outcome. Here, we review the current literature on cellular senescence, in epithelial-mammary cells, breast-cancer cells, and breast-tumor-microenvironment-resident cells. Furthermore, we discuss its putative role in breast-cancer response, regarding treatment and disease progression. In addition, we provide preliminary evidence of CS in breast-cancer-microenvironment cells, such as tumor-associated fibroblasts and tumor-infiltrating lymphocytes, by employing the novel GL13 lipofuscin stain, as a marker of cellular senescence.
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2
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Li J, Guan X, Fan Z, Ching LM, Li Y, Wang X, Cao WM, Liu DX. Non-Invasive Biomarkers for Early Detection of Breast Cancer. Cancers (Basel) 2020; 12:E2767. [PMID: 32992445 PMCID: PMC7601650 DOI: 10.3390/cancers12102767] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/24/2022] Open
Abstract
Breast cancer is the most common cancer in women worldwide. Accurate early diagnosis of breast cancer is critical in the management of the disease. Although mammogram screening has been widely used for breast cancer screening, high false-positive and false-negative rates and radiation from mammography have always been a concern. Over the last 20 years, the emergence of "omics" strategies has resulted in significant advances in the search for non-invasive biomarkers for breast cancer diagnosis at an early stage. Circulating carcinoma antigens, circulating tumor cells, circulating cell-free tumor nucleic acids (DNA or RNA), circulating microRNAs, and circulating extracellular vesicles in the peripheral blood, nipple aspirate fluid, sweat, urine, and tears, as well as volatile organic compounds in the breath, have emerged as potential non-invasive diagnostic biomarkers to supplement current clinical approaches to earlier detection of breast cancer. In this review, we summarize the current progress of research in these areas.
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Affiliation(s)
- Jiawei Li
- The Centre for Biomedical and Chemical Sciences, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland 1010, New Zealand; (J.L.); (X.G.); (Y.L.)
| | - Xin Guan
- The Centre for Biomedical and Chemical Sciences, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland 1010, New Zealand; (J.L.); (X.G.); (Y.L.)
- Department of Breast Surgery, the First Hospital of Jilin University, Jilin University, Changchun 130021, China;
| | - Zhimin Fan
- Department of Breast Surgery, the First Hospital of Jilin University, Jilin University, Changchun 130021, China;
| | - Lai-Ming Ching
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand;
| | - Yan Li
- The Centre for Biomedical and Chemical Sciences, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland 1010, New Zealand; (J.L.); (X.G.); (Y.L.)
| | - Xiaojia Wang
- Department of Breast Medical Oncology, Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital & Institute of Cancer and Basic Medicine (IBMC), Chinese Academy of Sciences, Hangzhou 310022, China;
| | - Wen-Ming Cao
- Department of Breast Medical Oncology, Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital & Institute of Cancer and Basic Medicine (IBMC), Chinese Academy of Sciences, Hangzhou 310022, China;
| | - Dong-Xu Liu
- The Centre for Biomedical and Chemical Sciences, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland 1010, New Zealand; (J.L.); (X.G.); (Y.L.)
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3
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Abstract
Could reprogramming the pretumor microenvironment transform cancer care?
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Affiliation(s)
- Thea D Tlsty
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - Philippe Gascard
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
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4
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Goh CW, Wu J, Ding S, Lin C, Chen X, Huang O, Chen W, Li Y, Shen K, Zhu L. Invasive ductal carcinoma with coexisting ductal carcinoma in situ (IDC/DCIS) versus pure invasive ductal carcinoma (IDC): a comparison of clinicopathological characteristics, molecular subtypes, and clinical outcomes. J Cancer Res Clin Oncol 2019; 145:1877-1886. [DOI: 10.1007/s00432-019-02930-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 05/06/2019] [Indexed: 12/26/2022]
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5
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Regional methylome profiling reveals dynamic epigenetic heterogeneity and convergent hypomethylation of stem cell quiescence-associated genes in breast cancer following neoadjuvant chemotherapy. Cell Biosci 2019; 9:16. [PMID: 30774927 PMCID: PMC6367786 DOI: 10.1186/s13578-019-0278-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/28/2019] [Indexed: 12/17/2022] Open
Abstract
Background Neoadjuvant chemotherapy (NAC) induces a pathological complete response (pCR) in ~ 30% of patients with breast cancer. However, aberrant DNA methylation alterations are frequent events during breast cancer progression and acquisition of chemoresistance. We aimed to characterize the inter- and intra-tumor methylation heterogeneity (MH) in breast cancer following NAC. Methods DNA methylation profiles of spatially separated regions of breast tumors before and after NAC treatment were investigated using high-density methylation microarray. Methylation levels of genes of interest were further examined using multiplexed MethyLight droplet digital PCR (ddPCR). Results We have discovered different levels of intra-tumor MH in breast cancer patients. Moreover, NAC dramatically altered the methylation profiles and such changes were highly heterogeneous between the patients. Despite the high inter-patient heterogeneity, we identified that stem cell quiescence-associated genes ALDH1L1, HOPX, WNT5A and SOX9 were convergently hypomethylated across all the samples after NAC treatment. Furthermore, by using MethyLight ddPCR, we verified that the methylation levels of these 4 genes were significantly lower in breast tumor samples after NAC than those before NAC. Conclusions Our study has revealed that NAC dramatically alters epigenetic heterogeneity in breast cancer and induces convergent hypomethylation of stem cell quiescence-associated genes, ALDH1L1, HOPX, WNT5A and SOX9, which can potentially be developed as therapeutic targets or biomarkers for chemoresistance. Electronic supplementary material The online version of this article (10.1186/s13578-019-0278-y) contains supplementary material, which is available to authorized users.
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6
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Abdallah MOE, Algizouli UK, Suliman MA, Abdulrahman RA, Koko M, Fessahaye G, Shakir JH, Fahal AH, Elhassan AM, Ibrahim ME, Mohamed HS. EBV Associated Breast Cancer Whole Methylome Analysis Reveals Viral and Developmental Enriched Pathways. Front Oncol 2018; 8:316. [PMID: 30151354 PMCID: PMC6099083 DOI: 10.3389/fonc.2018.00316] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/24/2018] [Indexed: 01/18/2023] Open
Abstract
Background: Breast cancer (BC) ranks among the most common cancers in Sudan and worldwide with hefty toll on female health and human resources. Recent studies have uncovered a common BC signature characterized by low frequency of oncogenic mutations and high frequency of epigenetic silencing of major BC tumor suppressor genes. Therefore, we conducted a pilot genome-wide methylome study to characterize aberrant DNA methylation in breast cancer. Results: Differential methylation analysis between primary tumor samples and normal samples from healthy adjacent tissues yielded 20,188 differentially methylated positions (DMPs), which is further divided into 13,633 hypermethylated sites corresponding to 5339 genes and 6,555 hypomethylated sites corresponding to 2811 genes. Moreover, bioinformatics analysis revealed epigenetic dysregulation of major developmental pathways including hippo signaling pathway. We also uncovered many clues to a possible role for EBV infection in BC. Conclusion: Our results clearly show the utility of epigenetic assays in interrogating breast cancer tumorigenesis, and pinpointing specific developmental and viral pathways dysregulation that might serve as potential biomarkers or targets for therapeutic interventions.
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Affiliation(s)
- Mohammad O E Abdallah
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Ubai K Algizouli
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Maram A Suliman
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Rawya A Abdulrahman
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Mahmoud Koko
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Ghimja Fessahaye
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Jamal H Shakir
- Department of Surgery, Khartoum Teaching Hospital, Khartoum, Sudan
| | - Ahmed H Fahal
- Department of Surgery, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Ahmed M Elhassan
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Muntaser E Ibrahim
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan
| | - Hiba S Mohamed
- Department of Molecular Biology, Institute of Endemic Disease, University of Khartoum, Khartoum, Sudan.,Department of Biology, Taibah University, Medina, Saudi Arabia
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7
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Mansoori Y, Tabei MB, Askari A, Izadi P, Daraei A, Naghizadeh MM, Zendehbad Z, Bastami M, Nariman-Saleh-Fam Z, Mansoori H, Tavakkoly-Bazzaz J. A link between expression level of long-non-coding RNA ZFAS1 in breast tissue of healthy women and obesity. Int J Biol Markers 2018; 33:500-506. [PMID: 29690801 DOI: 10.1177/1724600818762258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Epidemiological and experimental literature indicates that the risk of breast cancer incidence is strongly linked to hormone-dependent factors, including reproductive history and obesity. However, the molecular mechanisms underlying the association between these factors and breast cancer risk are poorly understood. The aim of this study, therefore, was to determine whether obesity and reproductive history are associated with expression levels of two breast cancer-related long non-coding RNAs (lncRNAs), namely ZFAS1 and SRA1 in cancer-free breast tissues of women. METHODS In the current research, 145 healthy women were recruited, and the quantitative expression levels of the two lncRNAs were determined through qPCR assay after gathering the mammoplasty breast tissue samples. RESULTS It was found that women with body mass index (BMI)≥30 kg/m2 and BMI 25-29 kg/m2 show a low expression of ZFAS1 compared to the BMI<25 kg/m2 (P=0.031 and P=0.027, respectively). Then, the correlation analysis disclosed a negative correlation of ZFAS1 low expression with increasing BMI (r=-0.194, P=0.019). Interestingly, this analysis demonstrated a negative correlation between low expression of the ZFAS1 and high BMI in women with menarche age below 14 (r=-221; P=0.028). Lastly, it was also revealed that there was a negative association of the low expression level of ZFAS1 with increasing BMI in women through regression models (B=-0.048, P=0.019). CONCLUSIONS These findings suggest interesting clues about the links between high BMI and the expression levels of ZFAS1 in non-diseased breasts that may help us better understand the underlying mechanisms through which obesity contributes to breast carcinogenesis. However, such results need more validations in future research.
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Affiliation(s)
- Yaser Mansoori
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran
| | - Mohammad Bagher Tabei
- Department of Medical Genetics, School of Medical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alireza Askari
- Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran.,Bone and Joint Reconstraction Research Center, Shafa Orthopedic Haspital, Iran University of Medical Sciences, Tehran, IR Iran
| | - Pantea Izadi
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdolreza Daraei
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
| | | | - Zahra Zendehbad
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Milad Bastami
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ziba Nariman-Saleh-Fam
- Women's Reproductive Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hosein Mansoori
- Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran.,Department of Medical Genetics, School of Medical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Javad Tavakkoly-Bazzaz
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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8
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Croes L, de Beeck KO, Pauwels P, Vanden Berghe W, Peeters M, Fransen E, Van Camp G. DFNA5 promoter methylation a marker for breast tumorigenesis. Oncotarget 2018; 8:31948-31958. [PMID: 28404884 PMCID: PMC5458261 DOI: 10.18632/oncotarget.16654] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/16/2017] [Indexed: 12/28/2022] Open
Abstract
Background Identification of methylation markers that are sensitive and specific for breast cancer may improve early detection. We hypothesize that DFNA5 promoter methylation can be a valuable epigenetic biomarker, based upon strong indications for its role as tumor suppressor gene and its function in regulated cell death. Results Statistically different levels of methylation were seen, with always very low levels in healthy breast reduction samples, very high levels in part of the adenocarcinoma samples and slightly increased levels in part of the normal tissue samples adjacent the tumor. One of the CpGs (CpG4) showed the best differentiation. A ROC curve for DFNA5 CpG4 methylation showed a sensitivity of 61.8% for the detection of breast cancer with a specificity of 100%. Materials and Methods We performed methylation analysis on four CpGs in the DFNA5 promoter region by bisulfite pyrosequencing on 123 primary breast adenocarcinomas and 24 healthy breast reductions. For 16 primary tumors, corresponding histological normal tissue adjacent to the tumor was available. Conclusions We conclude that DFNA5 methylation shows strong potential as a biomarker for detection of breast cancer. Slightly increased methylation in histologically normal breast tissue surrounding the tumor suggests that it may be a good early detection marker.
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Affiliation(s)
- Lieselot Croes
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium.,Center for Oncological Research, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium
| | - Ken Op de Beeck
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium.,Center for Oncological Research, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium
| | - Patrick Pauwels
- Center for Oncological Research, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium
| | - Wim Vanden Berghe
- Laboratory of Protein Chemistry, Proteomics and Epigenetic Signaling (PPES), Antwerp B-2610, Belgium
| | - Marc Peeters
- Center for Oncological Research, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium
| | - Erik Fransen
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium.,StatUa Center for Statistics, University of Antwerp, Antwerp B-2000, Belgium
| | - Guy Van Camp
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem B-2650, Belgium
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9
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Abstract
SUMMARYEpigenetic changes are present in all human cancers and are now known to cooperate with genetic alterations to drive the cancer phenotype. These changes involve DNA methylation, histone modifiers and readers, chromatin remodelers, microRNAs, and other components of chromatin. Cancer genetics and epigenetics are inextricably linked in generating the malignant phenotype; epigenetic changes can cause mutations in genes, and, conversely, mutations are frequently observed in genes that modify the epigenome. Epigenetic therapies, in which the goal is to reverse these changes, are now one standard of care for a preleukemic disorder and form of lymphoma. The application of epigenetic therapies in the treatment of solid tumors is also emerging as a viable therapeutic route.
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Affiliation(s)
- Stephen B Baylin
- Cancer Biology Program, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287
| | - Peter A Jones
- Van Andel Research Institute, Grand Rapids, Michigan 49503
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10
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Danforth DN. Genomic Changes in Normal Breast Tissue in Women at Normal Risk or at High Risk for Breast Cancer. BREAST CANCER-BASIC AND CLINICAL RESEARCH 2016; 10:109-46. [PMID: 27559297 PMCID: PMC4990153 DOI: 10.4137/bcbcr.s39384] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/17/2016] [Accepted: 04/19/2016] [Indexed: 12/12/2022]
Abstract
Sporadic breast cancer develops through the accumulation of molecular abnormalities in normal breast tissue, resulting from exposure to estrogens and other carcinogens beginning at adolescence and continuing throughout life. These molecular changes may take a variety of forms, including numerical and structural chromosomal abnormalities, epigenetic changes, and gene expression alterations. To characterize these abnormalities, a review of the literature has been conducted to define the molecular changes in each of the above major genomic categories in normal breast tissue considered to be either at normal risk or at high risk for sporadic breast cancer. This review indicates that normal risk breast tissues (such as reduction mammoplasty) contain evidence of early breast carcinogenesis including loss of heterozygosity, DNA methylation of tumor suppressor and other genes, and telomere shortening. In normal tissues at high risk for breast cancer (such as normal breast tissue adjacent to breast cancer or the contralateral breast), these changes persist, and are increased and accompanied by aneuploidy, increased genomic instability, a wide range of gene expression differences, development of large cancerized fields, and increased proliferation. These changes are consistent with early and long-standing exposure to carcinogens, especially estrogens. A model for the breast carcinogenic pathway in normal risk and high-risk breast tissues is proposed. These findings should clarify our understanding of breast carcinogenesis in normal breast tissue and promote development of improved methods for risk assessment and breast cancer prevention in women.
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Affiliation(s)
- David N Danforth
- Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Lesurf R, Aure M, Mørk H, Vitelli V, Lundgren S, Børresen-Dale AL, Kristensen V, Wärnberg F, Hallett M, Sørlie T, Sauer T, Geisler J, Hofvind S, Borgen E, Børresen-Dale AL, Engebråten O, Fodstad Ø, Garred Ø, Geitvik G, Kåresen R, Naume B, Mælandsmo G, Russnes H, Schlichting E, Sørlie T, Lingjærde O, Kristensen V, Sahlberg K, Skjerven H, Fritzman B. Molecular Features of Subtype-Specific Progression from Ductal Carcinoma In Situ to Invasive Breast Cancer. Cell Rep 2016; 16:1166-1179. [DOI: 10.1016/j.celrep.2016.06.051] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/03/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022] Open
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12
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Abstract
Aberrant DNA methylation is considered to be one of the most common hallmarks of cancer. Several recent advances in assessing the DNA methylome provide great promise for deciphering the cancer-specific DNA methylation patterns. Herein, we present the current key technologies used to detect high-throughput genome-wide DNA methylation, and the available cancer-associated methylation databases. Additionally, we focus on the computational methods for preprocessing, analyzing and interpreting the cancer methylome data. It not only discusses the challenges of the differentially methylated region calling and the prediction model construction but also highlights the biomarker investigation for cancer diagnosis, prognosis and response to treatment. Finally, some emerging challenges in the computational analysis of cancer methylome data are summarized.
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13
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MiRNAs and Other Epigenetic Changes as Biomarkers in Triple Negative Breast Cancer. Int J Mol Sci 2015; 16:28347-76. [PMID: 26633365 PMCID: PMC4691037 DOI: 10.3390/ijms161226090] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 10/30/2015] [Accepted: 11/12/2015] [Indexed: 02/06/2023] Open
Abstract
Triple negative breast cancer (TNBC) is characterised by the lack of receptors for estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2). Since it cannot be treated by current endocrine therapies which target these receptors and due to its aggressive nature, it has one of the worst prognoses of all breast cancer subtypes. The only treatments remain chemo- and/or radio-therapy and surgery and because of this, novel biomarkers or treatment targets are urgently required to improve disease outcomes. MicroRNAs represent an attractive candidate for targeted therapies against TNBC, due to their natural ability to act as antisense interactors and regulators of entire gene sets involved in malignancy and their superiority over mRNA profiling to accurately classify disease. Here we review the current knowledge regarding miRNAs as biomarkers in TNBC and their potential use as therapeutic targets in this disease. Further, we review other epigenetic changes and interactions of these changes with microRNAs in this breast cancer subtype, which may lead to the discovery of new treatment targets for TNBC.
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14
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Yaglom JA, McFarland C, Mirny L, Sherman MY. Oncogene-triggered suppression of DNA repair leads to DNA instability in cancer. Oncotarget 2015; 5:8367-78. [PMID: 25252808 PMCID: PMC4226689 DOI: 10.18632/oncotarget.2259] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
DNA instability is an important contributor to cancer development. Previously, defects in the chromosome segregation and excessive DNA double strand breaks due to the replication or oxidative stresses were implicated in DNA instability in cancer. Here, we demonstrate that DNA instability can directly result from the oncogene-induced senescence signaling. Expression of the activated form of Her2 oncogene, NeuT, in immortalized breast epithelial cells led to downregulation of the major DNA repair factor histone H2AX and a number of other components of the HR and NHEJ double strand DNA breaks repair pathways. H2AX expression was regulated at the transcriptional level via a senescence pathway involving p21-mediated regulation of CDK and Rb1. The p21-dependent downregulation of H2AX was seen both in cell culture and the MMTV-neu mouse model of Her2-positive breast cancer. Importantly, downregulation of H2AX upon Her2/NeuT expression impaired repair of double strand DNA breaks. This impairment resulted in both increased DNA instability in the form of somatic copy number alterations, and in increased sensitivity to the chemotherapeutic drug doxorubicin. Overall, these findings indicate that the Her2/NeuT oncogene signaling directly potentiates DNA instability and increases sensitivity to DNA damaging treatments.
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Affiliation(s)
- Julia A Yaglom
- Department Biochemistry, Boston University School of Medicine, Boston, MA
| | | | - Leonid Mirny
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA
| | - Michael Y Sherman
- Department Biochemistry, Boston University School of Medicine, Boston, MA
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15
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Field cancerization in mammary carcinogenesis — Implications for prevention and treatment of breast cancer. Exp Mol Pathol 2012; 93:391-8. [DOI: 10.1016/j.yexmp.2012.10.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 10/20/2012] [Indexed: 02/07/2023]
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16
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Locke WJ, Clark SJ. Epigenome remodelling in breast cancer: insights from an early in vitro model of carcinogenesis. Breast Cancer Res 2012; 14:215. [PMID: 23168266 PMCID: PMC4053120 DOI: 10.1186/bcr3237] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Epigenetic gene regulation has influence over a diverse range of cellular functions, including the maintenance of pluripotency, differentiation, and cellular identity, and is deregulated in many diseases, including cancer. Whereas the involvement of epigenetic dysregulation in cancer is well documented, much of the mechanistic detail involved in triggering these changes remains unclear. In the current age of genomics, the development of new sequencing technologies has seen an influx of genomic and epigenomic data and drastic improvements in both resolution and coverage. Studies in cancer cell lines and clinical samples using next-generation sequencing are rapidly delivering spectacular insights into the nature of the cancer genome and epigenome. Despite these improvements in technology, the timing and relationship between genetic and epigenetic changes that occur during the process of carcinogenesis are still unclear. In particular, what changes to the epigenome are playing a driving role during carcinogenesis and what influence the temporal nature of these changes has on cancer progression are not known. Understanding the early epigenetic changes driving breast cancer has the exciting potential to provide a novel set of therapeutic targets or early-disease biomarkers or both. Therefore, it is important to find novel systems that permit the study of initial epigenetic events that potentially occur during the first stages of breast cancer. Non-malignant human mammary epithelial cells (HMECs) provide an exciting in vitro model of very early breast carcinogenesis. When grown in culture, HMECs are able to temporarily escape senescence and acquire a pre-malignant breast cancer-like phenotype (variant HMECs, or vHMECs). Cultured HMECs are composed mainly of cells from the basal breast epithelial layer. Therefore, vHMECs are considered to represent the basal-like subtype of breast cancer. The transition from HMECs to vHMECs in culture recapitulates the epigenomic phenomena that occur during the progression from normal breast to pre-malignancy. Therefore, the HMEC model system provides the unique opportunity to study the very earliest epigenomic aberrations occurring during breast carcinogenesis and can give insight into the sequence of epigenomic events that lead to breast malignancy. This review provides an overview of epigenomic research in breast cancer and discusses in detail the utility of the HMEC model system to discover early epigenomic changes involved in breast carcinogenesis.
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17
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Abstract
Changes in gene expression that reset a cell program from a normal to a diseased state involve multiple genetic circuitries, creating a characteristic signature of gene expression that defines the cell's unique identity. Such signatures have been demonstrated to classify subtypes of breast cancers. Because DNA methylation is critical in programming gene expression, a change in methylation from a normal to diseased state should be similarly reflected in a signature of DNA methylation that involves multiple gene pathways. Whole-genome approaches have recently been used with different levels of success to delineate breast-cancer-specific DNA methylation signatures, and to test whether they can classify breast cancer and whether they could be associated with specific clinical outcomes. Recent work suggests that DNA methylation signatures will extend our ability to classify breast cancer and predict outcome beyond what is currently possible. DNA methylation is a robust biomarker, vastly more stable than RNA or proteins, and is therefore a promising target for the development of new approaches for diagnosis and prognosis of breast cancer and other diseases. Here, I review the scientific basis for using DNA methylation signatures in breast cancer classification and prognosis. I discuss the role of DNA methylation in normal gene regulation, the aberrations in DNA methylation in cancer, and candidate-gene and whole-genome approaches to classify breast cancer subtypes using DNA methylation markers.
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Affiliation(s)
- Moshe Szyf
- Department of Pharmacology and Therapeutics, Sackler Program in Epigenetics and Psychobiology, McGill University, 3,655 Sir William Osler Promenade, Montreal H3G1Y6, Canada
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18
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Abstract
Cancer patients' outcome and survival depends on the early diagnosis of malignant lesions. Several investigation methods used for the prevention and early detection strategies have specific limitations. More recently, epigenetic changes have been considered one of the most promising tools for the early diagnosis of cancer. Some of these epigenetic alterations including promoter hypermethylation of genes like P16INK4a, BRCA1, BRCA2, ERα and RARβ2, APC, and RASSF1A have been associated with early stages of mammary gland tumorigenesis and have been suggested to be included in the models that evaluate individual breast cancer risk. In lung cancer, P16INK4a and MGMT gene hypermethylation was observed in sputum years before clinical manifestation of the squamous cell carcinoma among smokers. Loss of GSTP1 function by DNA hypermethylation together with changes in the methylation levels of repetitive elements like LINE-1 and Sat2 was reported in prostatic preneoplastic lesions. Also, DNA hypermethylation for hMLH1 and MGMT DNA repair genes was reported in precursor lesions to colorectal cancer. These epigenetic alterations may be influenced by factors such as xenoestrogens, folate, and multivitamins. Detection of these changes may help determining cancer susceptibility and early diagnosis.
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Harrison MK, Adon AM, Saavedra HI. The G1 phase Cdks regulate the centrosome cycle and mediate oncogene-dependent centrosome amplification. Cell Div 2011; 6:2. [PMID: 21272329 PMCID: PMC3038874 DOI: 10.1186/1747-1028-6-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 01/27/2011] [Indexed: 11/10/2022] Open
Abstract
Because centrosome amplification generates aneuploidy and since centrosome amplification is ubiquitous in human tumors, a strong case is made for centrosome amplification being a major force in tumor biogenesis. Various evidence showing that oncogenes and altered tumor suppressors lead to centrosome amplification and aneuploidy suggests that oncogenes and altered tumor suppressors are a major source of genomic instability in tumors, and that they generate those abnormal processes to initiate and sustain tumorigenesis. We discuss how altered tumor suppressors and oncogenes utilize the cell cycle regulatory machinery to signal centrosome amplification and aneuploidy.
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Affiliation(s)
- Mary K Harrison
- Emory University, Department of Radiation Oncology, Winship Cancer Institute, 1701 Uppergate Drive, Atlanta, Georgia, 30322, USA.
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20
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Zeng X, Shaikh FY, Harrison MK, Adon AM, Trimboli AJ, Carroll KA, Sharma N, Timmers C, Chodosh LA, Leone G, Saavedra HI. The Ras oncogene signals centrosome amplification in mammary epithelial cells through cyclin D1/Cdk4 and Nek2. Oncogene 2010; 29:5103-12. [PMID: 20581865 DOI: 10.1038/onc.2010.253] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Centrosome amplification (CA) contributes to carcinogenesis by generating aneuploidy. Elevated frequencies of CA in most benign breast lesions and primary tumors suggest a causative role for CA in breast cancers. Clearly, identifying which and how altered signal transduction pathways contribute to CA is crucial to breast cancer control. Although a causative and cooperative role for c-Myc and Ras in mammary tumorigenesis is well documented, their ability to generate CA during mammary tumor initiation remains unexplored. To answer that question, K-Ras(G12D) and c-Myc were induced in mouse mammary glands. Although CA was observed in mammary tumors initiated by c-Myc or K-Ras(G12D), it was detected only in premalignant mammary lesions expressing K-Ras(G12D). CA, both in vivo and in vitro, was associated with increased expression of the centrosome-regulatory proteins, cyclin D1 and Nek2. Abolishing the expression of cyclin D1, Cdk4 or Nek2 in MCF10A human mammary epithelial cells expressing H-Ras(G12V) abrogated Ras-induced CA, whereas silencing cyclin E1 or B2 had no effect. Thus, we conclude that CA precedes mammary tumorigenesis, and interfering with centrosome-regulatory targets suppresses CA.
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Affiliation(s)
- X Zeng
- Department of Radiation Oncology, Emory University School of Medicine, and Emory Winship Cancer Institute, Atlanta, GA 30322, USA
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21
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Sommer J, Itani DM, Homlar KC, Keedy VL, Halpern JL, Holt GE, Schwartz HS, Coffin CM, Kelley MJ, Cates JMM. Methylthioadenosine phosphorylase and activated insulin-like growth factor-1 receptor/insulin receptor: potential therapeutic targets in chordoma. J Pathol 2010; 220:608-17. [PMID: 20140939 DOI: 10.1002/path.2679] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Currently there is no effective chemotherapy for chordoma. Recent studies report co-expression of insulin-like growth factor-1 receptor (IGF1R) and its cognate ligand in chordoma, but it is unknown whether this receptor tyrosine kinase is activated in these tumours. Additionally, genetic studies have confirmed frequent deletions of chromosome 9p in chordomas, which encompasses the cyclin-dependent kinase inhibitor 2A (CDKN2A) locus. Another gene in this region, methylthioadenosine phosphorylase (MTAP), is an essential enzyme of the purine salvage pathway and has therapeutic relevance because MTAP-deficient cells are particularly sensitive to inhibitors of de novo purine synthesis. We investigated whether these pathways might be potential therapeutic targets for chordoma. Paraffin-embedded tissue samples from 30 chordomas were analysed by immunohistochemistry for expression of the phosphorylated isoforms of IGF1R or the insulin receptor (pIGF1R/pIR) and selected downstream signalling molecules, including BCL2-associated agonist of cell death protein (BAD). Expression of CDKN2A and MTAP proteins was also assessed. Skeletal chondrosarcomas, benign notochordal cell tumours, and fetal notochord were studied for comparison. Phosphorylated IGF1R/IR was detected in 41% of chordomas, together with activated downstream signalling molecules, and pIGF1R/pIR was absent in benign notochordal cell tumours and fetal notochord. Thirty-nine per cent of chordomas were negative for MTAP immunoreactivity. Patients with pIGF1R/pIR-positive tumours showed significantly decreased median disease-free survival in multivariate survival analysis (p = 0.036), whereas phosphorylation of BAD at serine-99 was found to be associated with a favourable prognosis (p = 0.002). Approximately 40% of chordomas demonstrate evidence of activation of the IGF1R/IR signalling pathway or loss of a key enzyme in the purine salvage pathway. Aberrant signalling cascades and disrupted metabolic pathways such as these may represent opportunities for novel targeted therapeutic approaches for the treatment of chordoma.
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Affiliation(s)
- Josh Sommer
- Chordoma Foundation, Greensboro, NC, USA, and Division of Medical Oncology, Department of Medicine, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC, USA.
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22
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Korkola J, Gray JW. Breast cancer genomes--form and function. Curr Opin Genet Dev 2010; 20:4-14. [PMID: 20060285 DOI: 10.1016/j.gde.2009.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 11/25/2009] [Accepted: 11/27/2009] [Indexed: 01/23/2023]
Abstract
This review summarizes advances in our understanding of the genomic and epigenomic abnormalities in breast cancers that are being revealed by the increasingly powerful suite of genomic analysis technologies. It summarizes the remarkable genomic heterogeneity that characterizes the disease, describes mechanisms that shape cancer genomes as they evolve toward metastasis, summarizes important recurrent aberrations that exist in spite of the genomic chaos and that contribute to breast cancer pathophysiology, and describes the use of preclinical models to identify drugs that will be effective against subsets of breast cancers carrying specific genomic and epigenomic abnormalities.
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Affiliation(s)
- James Korkola
- Life Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS977-250, Berkeley, CA 94127, United States
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23
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Thompson PA, Hsu CH, Green S, Stopeck AT, Johnson K, Alberts DS, Chow HHS. Sulindac and sulindac metabolites in nipple aspirate fluid and effect on drug targets in a phase I trial. Cancer Prev Res (Phila) 2010; 3:101-7. [PMID: 20051377 PMCID: PMC3993089 DOI: 10.1158/1940-6207.capr-09-0120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Regular use of nonsteroidal anti-inflammatory drugs (NSAID) has been associated with reduced risk of breast cancer. Sulindac, a nonselective NSAID with both cyclooxygenase-2-dependent and -independent activities, is a candidate for breast chemoprevention. We conducted a phase Ib trial in 30 women at increased risk for breast cancer to evaluate the breast tissue distribution of sulindac at two dose levels (150 mg daily and 150 mg twice daily for 6 weeks), using nipple aspirate fluid (NAF) as a surrogate of breast tissue drug exposure. We also explored the effect of sulindac on drug-induced biomarkers in NAF. We show that sulindac and its metabolites partition to human breast as measured by NAF levels. Sulindac intervention did not decrease 13,14-dihydro-15-keto prostaglandin A(2), a stable derivative of prostaglandin E(2), in NAF, but exposure was associated with a significant trend towards higher levels of growth differentiation factor 15 in NAF in women receiving 150 mg twice daily (P = 0.038). These results are the first to show partitioning of sulindac and metabolites to human breast tissue and the first evidence for a potential dose-dependent effect of sulindac on growth differentiation factor 15 levels in NAF.
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Liu T, Niu Y, Yu Y, Liu Y, Zhang F. Increased gamma-tubulin expression and P16INK4A promoter methylation occur together in preinvasive lesions and carcinomas of the breast. Ann Oncol 2009; 20:441-8. [PMID: 19131428 DOI: 10.1093/annonc/mdn651] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Loss of p16(INK4A) due to promoter hypermethylation is correlated with the ability to acquire centrosomal abnormalities in variant human mammary epithelial cells. gamma-Tubulin is a highly conserved component of centrosome in most animal cells and gamma-tubulin protein overexpression could lead to centrosome aberration. MATERIALS AND METHODS A large series of breast premalignant lesions and carcinoma was analyzed. Real-time quantitative PCR and immunohistochemistry were carried out to measure gamma-tubulin copy numbers and protein expression. MethyLight and immunohistochemistry were carried out to determine p16(INK4A) methylation and protein expression. RESULTS gamma-Tubulin protein expression was concordant with gene amplification; both of them were found to increase with atypical ductal hyperplasia-carcinoma sequence. The median value and positive rate of p16(INK4a) methylation increased while protein expression displayed a decreasing trend. P16(INK4a) methylation showed a firm association with gamma-tubulin gene amplification. CONCLUSION gamma-Tubulin gene amplification and the concomitant protein overexpression present not only in invasive carcinoma but also in a significant fraction of atypical hyperplasia and in situ carcinomas. P16(INK4a) methylation and gamma-tubulin gene amplification had a synergistic effect on tumor progression. The synergism might arise as a result of the combined influence that p16(INK4a) and gamma-tubulin have on the G1-S cell cycle checkpoints and centrosome.
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Affiliation(s)
- T Liu
- Breast Cancer Research Key Laboratory of National Education Ministry, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
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25
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Hu M, Polyak K. Molecular characterisation of the tumour microenvironment in breast cancer. Eur J Cancer 2008; 44:2760-5. [PMID: 19026532 PMCID: PMC2729518 DOI: 10.1016/j.ejca.2008.09.038] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 09/23/2008] [Indexed: 12/30/2022]
Abstract
The tumour microenvironment plays important roles in cancer initiation, growth, progression, invasion and metastasis, yet the molecular basis underlying these tumour-promoting effects is not fully delineated. Recent advances in gene expression, genetic and epigenetic profiling of stromal cells have improved our understanding of how mesenchymal-epithelial cell interactions may create a permissive microenvironment for malignancy and identified potential targets for cancer prevention and treatment including chemokine and cytokine networks. However, translating these findings into clinical practice may be difficult due to the complexity and redundancy of the interactions and the inherent ability of tumour epithelial cells to evolve and thrive in diverse environmental conditions.
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Affiliation(s)
- Min Hu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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26
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Stein GS, Davie JR, Knowlton JR, Zaidi SK. Nuclear microenvironments and cancer. J Cell Biochem 2008; 104:1949-52. [PMID: 18649350 DOI: 10.1002/jcb.21846] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nucleic acids and regulatory proteins are architecturally organized in nuclear microenvironments. The compartmentalization of regulatory machinery for gene expression, replication and repair, is obligatory for fidelity of biological control. Perturbations in the organization, assembly and integration of regulatory machinery have been functionally linked to the onset and progression of tumorigenesis. The combined application of cellular, molecular, biochemical and in vivo genetic approaches, together with structural biology, genomics, proteomics and bioinformatics, will likely lead to new approaches in cancer diagnostics and therapy.
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Affiliation(s)
- Gary S Stein
- Department of Cell Biology, S3-310, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, Massachusetts 01655, USA.
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27
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Sexton K, Balharry D, BéruBé KA. Genomic biomarkers of pulmonary exposure to tobacco smoke components. Pharmacogenet Genomics 2008; 18:853-60. [PMID: 18794723 DOI: 10.1097/fpc.0b013e328307bddf] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Associations between smoking and the development of tobacco-related diseases in humans have historically been assessed by epidemiological studies. These studies are further complicated by the number of chemicals used in tobacco and individual smoking habits. An alternative approach is required to assess the biological responses. OBJECTIVE Toxicogenomics was carried out to identify early molecular markers for events in pulmonary injury resulting from tobacco smoke components (TSC) exposure. MATERIALS AND METHODS EpiAirway-100 cells were exposed at the air/liquid interface to representative particle (nicotine; cadmium) and vapour phase [formaldehyde (FA) and ethyl carbamate] components of cigarette smoke. Microarray technology was used to compare expression profiles of human genes associated with toxicity and drug resistance, from control and TSC-treated respiratory epithelium (n=5/dose). RESULTS Using the GEArray 'toxicology and drug resistance' microarray followed by significance analysis of microarray analysis, 42 mRNA transcripts were found to be significantly altered by the TSC exposure. The vapour [ethyl carbamate, FA and particle (nicotine, cadmium)] phase TSC exhibited differential transcriptional responses that could not be attributed to their chemical phase. The transcriptional changes could be classified according to a functional family, where ethyl carbamate, FA and cadmium classified as carcinogens, demonstrated the highest gene homology when compared with the noncarcinogen, nicotine. DISCUSSION Analysis of the microarray data and further confirmation (reverse transcriptase-PCR) identified three potential biomarkers for TSC-induced injury. These three genes (CYP7A1, HMOX1 and PTGS1) are highly upregulated and have been linked with mechanistic pathways of disease.
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Affiliation(s)
- Keith Sexton
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, UK.
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28
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Abstract
The retinoblastoma (RB) tumour suppressor gene is functionally inactivated in a broad range of paediatric and adult cancers, and a plethora of cellular functions and partners have been identified for the RB protein. Data from human tumours and studies from mouse models indicate that loss of RB function contributes to both cancer initiation and progression. However, we still do not know the identity of the cell types in which RB normally prevents cancer initiation in vivo, and the specific functions of RB that suppress distinct aspects of the tumorigenic process are poorly understood.
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Affiliation(s)
- Deborah L Burkhart
- Cancer Biology Program, Stanford University School of Medicine, Stanford, California 94305, USA
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29
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Carraway HE, Wang S, Blackford A, Guo M, Powers P, Jeter S, Davidson NE, Argani P, Terrell K, Herman JG, Lange JR. Promoter hypermethylation in sentinel lymph nodes as a marker for breast cancer recurrence. Breast Cancer Res Treat 2008; 114:315-25. [PMID: 18404369 DOI: 10.1007/s10549-008-0004-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 04/01/2008] [Indexed: 12/16/2022]
Abstract
PURPOSE Promoter methylation of tumor suppressor genes in histologically negative sentinel lymph nodes (HNSN) of early stage breast cancer patients has not been extensively studied. This study evaluates the methylation frequency and pattern in HNSN to determine if detection of hypermethylation of one or more genes is associated with an increased recurrence risk in node negative breast cancer. EXPERIMENTAL DESIGN In 1998, a prospective study of patients with early stage breast cancer and HNSN was initiated in order to correlate sentinel node analysis with clinical outcome. Nodal tissue was selected from 120 HNSN patients for methylation analysis in at least one and up to six sentinel nodes using a panel of nine genes. Corresponding primary breast tumors from 79 patients were also evaluated for hypermethylation. Methylation analysis was performed using nested Methylation Sensitive PCR (n-MSP). Logistical regression was used to evaluate the relationship between clinical recurrence and methylation status. RESULTS Over a median follow-up of 79 months, 13 of the 120 patients had clinical recurrence. Hypermethylation of genes was frequently observed in HNSN, but there was no correlation of methylation pattern and clinical recurrence. However, increased frequency of gene methylation of the primary tumor correlated with clinical recurrence. CONCLUSIONS Although hypermethylation of multiple genes occurs frequently in HNSN of breast cancer patients, it is not associated with breast cancer recurrence in the first 7 years of clinical follow-up.
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Affiliation(s)
- Hetty E Carraway
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins Hospital, Baltimore, MD 21231, USA.
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30
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Hinshelwood RA, Huschtscha LI, Melki J, Stirzaker C, Abdipranoto A, Vissel B, Ravasi T, Wells CA, Hume DA, Reddel RR, Clark SJ. Concordant epigenetic silencing of transforming growth factor-beta signaling pathway genes occurs early in breast carcinogenesis. Cancer Res 2008; 67:11517-27. [PMID: 18089780 DOI: 10.1158/0008-5472.can-07-1284] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Human mammary epithelial cells (HMEC) grown under standard cell culture conditions enter a growth phase referred to as selection, but a subpopulation is able to escape from arrest and continue to proliferate. These cells, called post-selection or variant HMECs, may be derived from progenitor cells found in normal mammary epithelium that subsequently acquire premalignant lesions, including p16(INK4A) promoter hypermethylation. Epigenetic silencing of tumor suppressor genes through DNA methylation and histone modification is an early event in tumorigenesis. A major challenge is to find genes or gene pathways that are commonly silenced to provide early epigenetic diagnostic and therapeutic cancer targets. To identify very early epigenetic events that occur in breast cancer, we used microarrays to screen for gene pathways that were suppressed in post-selection HMECs but reactivated after treatment with the demethylation agent 5-aza-2'-deoxycytidine. We found that several members of the transforming growth factor beta (TGF-beta) signaling pathway were consistently down-regulated in the post-selection HMEC populations, and this was associated with a marked decrease in Smad4 nuclear staining. Gene suppression was not associated with DNA methylation but with chromatin remodeling, involving a decrease in histone H3 lysine 27 trimethylation and an increase in histone H3 lysine 9 dimethylation and deacetylation. These results show for the first time that TGF-beta2, its receptors TGF-beta R1 and TGF-beta R2, and activator thrombospondin-1 are concordantly suppressed early in breast carcinogenesis by histone modifications and indicate that the TGF-beta signaling pathway is a novel target for gene activation by epigenetic therapy.
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Datta S, Hoenerhoff MJ, Bommi P, Sainger R, Guo WJ, Dimri M, Band H, Band V, Green JE, Dimri GP. Bmi-1 cooperates with H-Ras to transform human mammary epithelial cells via dysregulation of multiple growth-regulatory pathways. Cancer Res 2007; 67:10286-95. [PMID: 17974970 DOI: 10.1158/0008-5472.can-07-1636] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Elevated expression of Bmi-1 is associated with many cancers, including breast cancer. Here, we examined the oncogenic potential of Bmi-1 in MCF10A cells, a spontaneously immortalized, nontransformed strain of human mammary epithelial cells (HMEC). Bmi-1 overexpression alone in MCF10A cells did not result in oncogenic transformation. However, Bmi-1 co-overexpression with activated H-Ras (RasG12V) resulted in efficient transformation of MCF10A cells in vitro. Although early-passage H-Ras-expressing MCF10A cells were not transformed, late-passage H-Ras-expressing cells exhibited features of transformation in vitro. Early- and late-passage H-Ras-expressing cells also differed in levels of expression of H-Ras and Ki-67, a marker of proliferation. Subsets of early-passage H-Ras-expressing cells exhibited high Ras expression and were negative for Ki-67, whereas most late-passage H-Ras-expressing cells expressed low levels of Ras and were Ki-67 positive. Injection of late-passage H-Ras-expressing cells in severe combined immunodeficient mice formed carcinomas with leiomatous, hemangiomatous, and mast cell components; these tumors were quite distinct from those induced by late-passage cells co-overexpressing Bmi-1 and H-Ras, which formed poorly differentiated carcinomas with spindle cell features. Bmi-1 and H-Ras co-overexpression in MCF10A cells also induced features of epithelial-to-mesenchymal transition. Importantly, Bmi-1 inhibited senescence and permitted proliferation of cells expressing high levels of Ras. Examination of various growth-regulatory pathways suggested that Bmi-1 overexpression together with H-Ras promotes HMEC transformation and breast oncogenesis by deregulation of multiple growth-regulatory pathways by p16(INK4a)-independent mechanisms.
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Affiliation(s)
- Sonal Datta
- Division of Cancer Biology and Department of Medicine, Feinberg School of Medicine, Northwestern University, Evanston, IL 60201, USA
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