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Single-cell genomic profile-based analysis of tissue differentiation in colorectal cancer. SCIENCE CHINA-LIFE SCIENCES 2020; 64:1311-1325. [PMID: 33141303 DOI: 10.1007/s11427-020-1811-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
Colorectal cancer (CRC) progression is associated with cancer cell dedifferentiation and sternness acquisition. Several methods have been developed to identify sternness signatures in CRCs. However, studies that directly measured the degree of dedifferentiation in CRC tissues are limited. It is unclear how the differentiation states change during CRC progression. To address this, we develop a method to analyze the tissue differentiation spectrum in colorectal cancer using normal gastrointestinal single-cell transcriptome data. Applying this method on 281 tumor samples from The Cancer Genome Atlas Colon Adenocarcinoma dataset, we identified three major CRC subtypes with distinct tissue differentiation pattern. We observed that differentiation states are closely correlated with anti-tumor immune response and patient outcomes in CRC. Highly dedifferentiated CRC samples escaped the immune surveillance and exhibited poor outcomes; mildly dedifferentiated CRC samples showed resistance to anti-tumor immune responses and had a worse survival rate; well-differentiated CRC samples showed sustained anti-tumor immune responses and had a good prognosis. Overall, the spectrum of tissue differentiation observed in CRCs can be used for future clinical risk stratification and subtype-based therapy selection.
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2
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Regenerative medicine and injection therapies in stress urinary incontinence. Nat Rev Urol 2020; 17:151-161. [PMID: 31974507 DOI: 10.1038/s41585-019-0273-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2019] [Indexed: 02/06/2023]
Abstract
Stress urinary incontinence (SUI) is a common and bothersome condition. Anti-incontinence surgery has high cure rates, but concerns about mesh tapes have resulted in the resurgence of surgical procedures that involve increased abdominopelvic dissection and morbidity. Injection therapy with urethral bulking agents or stem cell formulations have been developed as minimally invasive alternatives. Many synthetic and biological bulking agents have been trialled, but several have been discontinued owing to safety concerns. The use of Macroplastique and Contigen has the largest evidence base, but, overall, success rates seem to be similar between the various agents and positive outcomes are poorly sustained for more than 6 months. Furthermore, subjective cure rates, although initially high, also deteriorate over time. The available data consistently demonstrate manifestly poorer outcomes for injection therapies than for surgery. Stem cell treatments are thought to functionally regenerate the urethral sphincter in patients with suspected intrinsic sphincter deficiency. Autologous adipose and muscle-derived stem cells seem to be the intuitive cell source, as they are comparatively abundant, can be harvested and cause minimal donor site morbidity. To date, only a few small clinical studies have been reported and most data are derived from animal models. The success rates of stem cell injection therapies seem to be comparable with those of bulking agents.
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Alguacil-Núñez C, Ferrer-Ortiz I, García-Verdú E, López-Pirez P, Llorente-Cortijo IM, Sainz B. Current perspectives on the crosstalk between lung cancer stem cells and cancer-associated fibroblasts. Crit Rev Oncol Hematol 2018; 125:102-110. [PMID: 29650269 DOI: 10.1016/j.critrevonc.2018.02.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/17/2018] [Accepted: 02/26/2018] [Indexed: 12/16/2022] Open
Abstract
Lung cancer, in particular non-small cell lung carcinoma (NSCLC), is the second most common cancer in both men and women and the leading cause of cancer-related deaths worldwide. Its prognosis and diagnosis are determined by several driver mutations and diverse risk factors (e.g. smoking). While immunotherapy has proven effective in some patients, treatment of NSCLC using conventional chemotherapy is largely ineffective. The latter is believed to be due to the existence of a subpopulation of stem-like, highly tumorigenic and chemoresistant cells within the tumor population known as cancer stem cells (CSC). To complicate the situation, CSCs interact with the tumor microenvironment, which include cancer-associated fibroblasts (CAFs), immune cells, endothelial cells, growth factors, cytokines and connective tissue components, which via a dynamic crosstalk, composed of proteins and exosomes, activates the CSC compartment. In this review, we analyze the crosstalk between CSCs and CAFs, the primary component of the NSCLC microenvironment, at the molecular and extracellular level and contemplate therapies to disrupt this communication.
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Affiliation(s)
- Cristina Alguacil-Núñez
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Inés Ferrer-Ortiz
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Elena García-Verdú
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Pilar López-Pirez
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Irene Maria Llorente-Cortijo
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Bruno Sainz
- Department of Biochemistry, Cancer Stem Cell and Tumor Microenvironment Group, Universidad Autónoma de Madrid (UAM), Madrid, Spain; Department of Cancer Biology, Instituto de Investigaciones Biomédicas "Alberto Sols" (IIBM), CSIC-UAM, Madrid, Spain; Chronic Diseases and Cancer Area 3 - Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
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4
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Colorectal Cancer: From the Genetic Model to Posttranscriptional Regulation by Noncoding RNAs. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7354260. [PMID: 28573140 PMCID: PMC5442347 DOI: 10.1155/2017/7354260] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 02/16/2017] [Indexed: 12/11/2022]
Abstract
Colorectal cancer is the third most common form of cancer in developed countries and, despite the improvements achieved in its treatment options, remains as one of the main causes of cancer-related death. In this review, we first focus on colorectal carcinogenesis and on the genetic and epigenetic alterations involved. In addition, noncoding RNAs have been shown to be important regulators of gene expression. We present a general overview of what is known about these molecules and their role and dysregulation in cancer, with a special focus on the biogenesis, characteristics, and function of microRNAs. These molecules are important regulators of carcinogenesis, progression, invasion, angiogenesis, and metastases in cancer, including colorectal cancer. For this reason, miRNAs can be used as potential biomarkers for diagnosis, prognosis, and efficacy of chemotherapeutic treatments, or even as therapeutic agents, or as targets by themselves. Thus, this review highlights the importance of miRNAs in the development, progression, diagnosis, and therapy of colorectal cancer and summarizes current therapeutic approaches for the treatment of colorectal cancer.
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5
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Lim B, Mun J, Kim SY. Intrinsic Molecular Processes: Impact on Mutagenesis. Trends Cancer 2017; 3:357-371. [PMID: 28718413 DOI: 10.1016/j.trecan.2017.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/23/2017] [Accepted: 03/23/2017] [Indexed: 02/07/2023]
Abstract
Mutations provide resources for genome evolution by generating genetic variability. In addition, mutations act as a driving force leading to disease pathogenesis, and thus have important implications for disease diagnosis, prognosis, and treatment. Understanding the mechanisms underlying how mutations occur is therefore of prime importance for elucidating evolutionary and pathogenic processes. Recent genomics studies have revealed that mutations occur non-randomly across the human genome. In particular, the distribution of mutations is highly associated with intrinsic molecular processes including transcription, chromatin organization, DNA replication timing, and DNA repair. Interplay between intrinsic processes and extrinsic mutagenic exposure may thus imprint a characteristic mutational landscape on tumors. We discuss the impact of intrinsic molecular processes on mutation acquisition in cancer.
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Affiliation(s)
- Byungho Lim
- Research Center for Drug Discovery Technology, Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, Daejeon, Korea
| | - Jihyeob Mun
- Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea; Department of Functional Genomics, University of Science and Technology, Daejeon, Korea
| | - Seon-Young Kim
- Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea; Department of Functional Genomics, University of Science and Technology, Daejeon, Korea.
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Abstract
Lung cancer remains a major cause of cancer-related deaths worldwide with unfavourable prognosis mainly due to the late stage of disease at presentation. High incidence and disease recurrence rates are a fact despite advances in treatment. Ongoing experimental and clinical observations suggest that the malignant phenotype in lung cancer is sustained by lung cancer stem cells (CSCs) which are putative stem cells situated throughout the airways that have the potential of initiating lung cancer formation. These cells share the common characteristic of increased proliferation and differentiation, long life span and resistance to chemotherapy and radiation therapy. This review summarises the current knowledge on their characteristics and phenotype.
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Affiliation(s)
- Georgia Hardavella
- 1 Department of Respiratory Medicine and Allergy, King's College, London, UK ; 2 Department of Respiratory Medicine, King's College Hospital, London, UK
| | - Rachel George
- 1 Department of Respiratory Medicine and Allergy, King's College, London, UK ; 2 Department of Respiratory Medicine, King's College Hospital, London, UK
| | - Tariq Sethi
- 1 Department of Respiratory Medicine and Allergy, King's College, London, UK ; 2 Department of Respiratory Medicine, King's College Hospital, London, UK
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7
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Marcucci F, Rumio C, Lefoulon F. Anti-Cancer Stem-like Cell Compounds in Clinical Development - An Overview and Critical Appraisal. Front Oncol 2016; 6:115. [PMID: 27242955 PMCID: PMC4861739 DOI: 10.3389/fonc.2016.00115] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/25/2016] [Indexed: 12/16/2022] Open
Abstract
Cancer stem-like cells (CSC) represent a subpopulation of tumor cells with elevated tumor-initiating potential. Upon differentiation, they replenish the bulk of the tumor cell population. Enhanced tumor-forming capacity, resistance to antitumor drugs, and metastasis-forming potential are the hallmark traits of CSCs. Given these properties, it is not surprising that CSCs have become a therapeutic target of prime interest in drug discovery. In fact, over the last few years, an enormous number of articles describing compounds endowed with anti-CSC activities have been published. In the meanwhile, several of these compounds and also approaches that are not based on the use of pharmacologically active compounds (e.g., vaccination, radiotherapy) have progressed into clinical studies. This article gives an overview of these compounds, proposes a tentative classification, and describes their biological properties and their developmental stage. Eventually, we discuss the optimal clinical setting for these compounds, the need for biomarkers allowing patient selection, the redundancy of CSC signaling pathways and the utility of employing combinations of anti-CSC compounds and the therapeutic limitations posed by the plasticity of CSCs.
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Affiliation(s)
- Fabrizio Marcucci
- Department of Pharmacological and Biomolecular Sciences, University of Milan , Milan , Italy
| | - Cristiano Rumio
- Department of Pharmacological and Biomolecular Sciences, University of Milan , Milan , Italy
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8
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Roman S, Agil A, Peran M, Alvaro-Galue E, Ruiz-Ojeda FJ, Fernández-Vázquez G, Marchal JA. Brown adipose tissue and novel therapeutic approaches to treat metabolic disorders. Transl Res 2015; 165:464-79. [PMID: 25433289 DOI: 10.1016/j.trsl.2014.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 10/16/2014] [Accepted: 11/04/2014] [Indexed: 01/08/2023]
Abstract
In humans, 2 functionally different types of adipose tissue coexist: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is involved in energy storage, whereas BAT is involved in energy expenditure. Increased amounts of WAT may contribute to the development of metabolic disorders, such as obesity-associated type 2 diabetes mellitus and cardiovascular diseases. In contrast, the thermogenic function of BAT allows high consumption of fatty acids because of the activity of uncoupling protein 1 in the internal mitochondrial membrane. Interestingly, obesity reduction and insulin sensitization have been achieved by BAT activation-regeneration in animal models. This review describes the origin, function, and differentiation mechanisms of BAT to identify new therapeutic strategies for the treatment of metabolic disorders related to obesity. On the basis of the animal studies, novel approaches for BAT regeneration combining stem cells from the adipose tissue with active components, such as melatonin, may have potential for the treatment of metabolic disorders in humans.
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Affiliation(s)
- Sabiniano Roman
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Tissue Engineering Group, Kroto Research Institute, University of Sheffield, Sheffield, UK
| | - Ahmad Agil
- Department of Pharmacology and Neurosciences Institute, Faculty of Medicine, Biosanitary Institute of Granada (ibs.GRANADA), Hospitals Unversity/University of Granada, Granada, Spain
| | - Macarena Peran
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Department of Health Sciences, University of Jaén, Jaén, Spain
| | - Eduardo Alvaro-Galue
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Wake Forest Institute for Regenerative Medicine Wake Forest School of Medicine, Winston Salem, NC
| | - Francisco J Ruiz-Ojeda
- Institute of Nutrition and Food Technology, Centre for Biomedical Research, University of Granada, Granada, Spain
| | | | - Juan A Marchal
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research, University of Granada, Granada, Spain; Department of Human Anatomy and Embryology, Biosanitary Institute of Granada (ibs.GRANADA), Hospitals Unversity/University of Granada, Granada, Spain.
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9
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Templeton AK, Miyamoto S, Babu A, Munshi A, Ramesh R. Cancer stem cells: progress and challenges in lung cancer. Stem Cell Investig 2014; 1:9. [PMID: 27358855 DOI: 10.3978/j.issn.2306-9759.2014.03.06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/07/2014] [Indexed: 12/17/2022]
Abstract
The identification of a subpopulation of tumor cells with stem cell-like characteristics first in hematological malignancies and later in solid tumors has emerged into a novel field of cancer research. It has been proposed that this aberrant population of cells now called "cancer stem cells" (CSCs) drives tumor initiation, progression, metastasis, recurrence, and drug resistance. CSCs have been shown to have the capacity of self-renewal and multipotency. Adopting strategies from the field of stem cell research has aided in identification, localization, and targeting of CSCs in many tumors. Despite the huge progress in other solid tumors such as brain, breast, and colon cancers no substantial advancements have been made in lung cancer. This is most likely due to the current rudimentary understanding of lung stem cell hierarchy and heterogeneous nature of lung disease. In this review, we will discuss the most recent findings related to identification of normal lung stem cells and CSCs, pathways involved in regulating the development of CSCs, and the importance of the stem cell niche in development and maintenance of CSCs. Additionally, we will examine the development and feasibility of novel CSC-targeted therapeutic strategies aimed at eradicating lung CSCs.
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Affiliation(s)
- Amanda K Templeton
- 1 Department of Pathology, 2 Peggy and Charles Stephenson Cancer Center, 3 Department of Radiation Oncology, 4 Graduate Program in Biomedical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Shinya Miyamoto
- 1 Department of Pathology, 2 Peggy and Charles Stephenson Cancer Center, 3 Department of Radiation Oncology, 4 Graduate Program in Biomedical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Anish Babu
- 1 Department of Pathology, 2 Peggy and Charles Stephenson Cancer Center, 3 Department of Radiation Oncology, 4 Graduate Program in Biomedical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Anupama Munshi
- 1 Department of Pathology, 2 Peggy and Charles Stephenson Cancer Center, 3 Department of Radiation Oncology, 4 Graduate Program in Biomedical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Rajagopal Ramesh
- 1 Department of Pathology, 2 Peggy and Charles Stephenson Cancer Center, 3 Department of Radiation Oncology, 4 Graduate Program in Biomedical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Abstract
Despite intense research efforts that have provided enormous insight, cancer continues to be a poorly understood disease. There has been much debate over whether the cancerous state can be said to originate in a single cell or whether it is a reflection of aberrant behaviour on the part of a 'society of cells'. This article presents, in the form of a debate conducted among the authors, three views of how the problem might be addressed. We do not claim that the views exhaust all possibilities. These views are (a) the tissue organization field theory (TOFT) that is based on a breakdown of tissue organization involving many cells from different embryological layers, (b) the cancer stem cell (CSC) hypothesis that focuses on genetic and epigenetic changes that take place within single cells, and (c) the proposition that rewiring of the cell's protein interaction networks mediated by intrinsically disordered proteins (IDPs) drives the tumorigenic process. The views are based on different philosophical approaches. In detail, they differ on some points and agree on others. It is left to the reader to decide whether one approach to understanding cancer appears more promising than the other.
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Affiliation(s)
- Carlos Sonnenschein
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA
- Centre Cavaillès, École Normale Supérieure, 45 rue d’Ulm, Paris 75005, France
| | - Ana M Soto
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA
- Centre Cavaillès, École Normale Supérieure, 45 rue d’Ulm, Paris 75005, France
| | - Annapoorni Rangarajan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Prakash Kulkarni
- Department of Urology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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11
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Emlet DR, Gupta P, Holgado-Madruga M, Del Vecchio CA, Mitra SS, Han SY, Li G, Jensen KC, Vogel H, Xu LW, Skirboll SS, Wong AJ. Targeting a glioblastoma cancer stem-cell population defined by EGF receptor variant III. Cancer Res 2014; 74:1238-49. [PMID: 24366881 PMCID: PMC5661963 DOI: 10.1158/0008-5472.can-13-1407] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The relationship between mutated proteins and the cancer stem-cell population is unclear. Glioblastoma tumors frequently express EGFRvIII, an EGF receptor (EGFR) variant that arises via gene rearrangement and amplification. However, expression of EGFRvIII is restricted despite the prevalence of the alteration. Here, we show that EGFRvIII is highly coexpressed with CD133 and that EGFRvIII(+)/CD133(+) defines the population of cancer stem cells (CSC) with the highest degree of self-renewal and tumor-initiating ability. EGFRvIII(+) cells are associated with other stem/progenitor markers, whereas markers of differentiation are found in EGFRvIII(-) cells. EGFRvIII expression is lost in standard cell culture, but its expression is maintained in tumor sphere culture, and cultured cells also retain the EGFRvIII(+)/CD133(+) coexpression, self-renewal, and tumor initiating abilities. Elimination of the EGFRvIII(+)/CD133(+) population using a bispecific antibody reduced tumorigenicity of implanted tumor cells better than any reagent directed against a single epitope. This work demonstrates that a mutated oncogene can have CSC-specific expression and be used to specifically target this population.
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Affiliation(s)
- David R. Emlet
- Brain Tumor Research Laboratories, Program in Cancer Biology, Stanford University Medical Center, Stanford, CA 94305
| | - Puja Gupta
- Brain Tumor Research Laboratories, Program in Cancer Biology, Stanford University Medical Center, Stanford, CA 94305
| | - Marina Holgado-Madruga
- Department of Physiology and Pharmacology, IBSAL, School of Medicine, University of Salamanca, C/Alfonso X El Sabio s/n. 37007 Salamanca, Spain
| | | | - Siddhartha S. Mitra
- Institute of Stem Cell Biology and Regenerative Medicine, 265 Campus Drive, Stanford, CA 94305
| | - Shuang-Yin Han
- Department of Gastroenterology, Henan Provincial People’s Hospital, Zhengzhou, Henan 450003, People’s Republic of China
| | - Gordon Li
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 943005
| | - Kristin C. Jensen
- Department of Pathology, Stanford University Medical Center, Stanford, CA, 94305
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94305
| | - Hannes Vogel
- Department of Pathology, Stanford University Medical Center, Stanford, CA, 94305
| | - Linda Wei Xu
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 943005
| | - Stephen S. Skirboll
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 943005
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94305
| | - Albert J. Wong
- Brain Tumor Research Laboratories, Program in Cancer Biology, Stanford University Medical Center, Stanford, CA 94305
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12
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Affiliation(s)
- James L. Sherley
- The Adult Stem Cell Technology Center; Boston Biomedical Research Institute; Watertown; MA; USA
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14
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Economopoulou P, Kaklamani VG, Siziopikou K. The role of cancer stem cells in breast cancer initiation and progression: potential cancer stem cell-directed therapies. Oncologist 2012; 17:1394-401. [PMID: 22941971 DOI: 10.1634/theoncologist.2012-0163] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recent studies have identified a small population of highly tumorigenic cells with stem cell properties in human breast and other solid tumors that are considered to be the source of tumor initiation and maintenance; these cells are referred to as cancer stem cells (CSCs). Preclinical data suggest that current breast cancer treatment strategies lead to CSC enrichment, contributing to chemotherapy and radiotherapy resistance, although a strong correlation with clinical parameters and prognosis is yet to be established. Importantly, overcoming treatment failure by effective targeting of CSCs may be an appealing approach, potentially leading to improved clinical outcomes for patients with breast cancer. Several preclinical studies provide promising results that support this hypothesis. The purpose of this review is to summarize the role of CSCs in breast cancer recurrence and resistance and to discuss current attempts of CSC targeting.
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15
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Christ B, Stock P. Mesenchymal stem cell-derived hepatocytes for functional liver replacement. Front Immunol 2012; 3:168. [PMID: 22737154 PMCID: PMC3381218 DOI: 10.3389/fimmu.2012.00168] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 06/04/2012] [Indexed: 12/14/2022] Open
Abstract
Mesenchymal stem cells represent an alternate cell source to substitute for primary hepatocytes in hepatocyte transplantation because of their multiple differentiation potential and nearly unlimited availability. They may differentiate into hepatocyte-like cells in vitro and maintain specific hepatocyte functions also after transplantation into the regenerating livers of mice or rats both under injury and non-injury conditions. Depending on the underlying liver disease their mode of action is either to replace the diseased liver tissue or to support liver regeneration through their anti-inflammatory and anti-apoptotic as well as their pro-proliferative action.
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Affiliation(s)
- Bruno Christ
- Applied Molecular Hepatology Laboratory, Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University Hospital Leipzig Leipzig, Germany
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16
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Dobrescu A, Chang M, Kirtani V, Turi GK, Hennawy R, Hindenburg AA. Study of Estrogen Receptor and Progesterone Receptor Expression in Breast Ductal Carcinoma In Situ by Immunohistochemical Staining in ER/PgR-Negative Invasive Breast Cancer. ISRN ONCOLOGY 2011; 2011:673790. [PMID: 22091428 PMCID: PMC3200125 DOI: 10.5402/2011/673790] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 05/09/2011] [Indexed: 11/23/2022]
Abstract
Background. To our knowledge, the hormone receptor status of noncontiguous ductal carcinoma in situ (DCIS) occurring concurrently in ER/PgR-negative invasive cancer has not been studied. The current study was undertaken to investigate the ER/PgR receptor status of DCIS of the breast in patients with ER/PgR-negative invasive breast cancer. Methods. We reviewed the immunohistochemical (IHC) staining for ER and PgR of 187 consecutive cases of ER/PgR-negative invasive breast cancers, collected from 1995 to 2002. To meet the criteria for the study, we evaluated ER/PgR expression of DCIS cancer outside of the invasive breast cancer. Results. A total of 37 cases of DCIS meeting the above criteria were identified. Of these, 16 cases (43.2%) showed positive staining for ER, PgR, or both. Conclusions. In our study of ER/PgR-negative invasive breast cancer we found that in 8% of cases noncontiguous ER/PR-positive DCIS was present. In light of this finding, it may be important for pathologists to evaluate the ER/PgR status of DCIS occurring in the presence of ER/PgR-negative invasive cancer, as this subgroup could be considered for chemoprevention.
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Affiliation(s)
- Andrei Dobrescu
- Division of Oncology/Hematology, Department of Medicine, Winthrop-University Hospital, 200 Old Country Road, Suite 450, Mineola, NY 11501, USA
| | - Monique Chang
- Division of Oncology/Hematology, Department of Medicine, Winthrop-University Hospital, 200 Old Country Road, Suite 450, Mineola, NY 11501, USA
| | - Vatsala Kirtani
- Division of Oncology/Hematology, Department of Medicine, Winthrop-University Hospital, 200 Old Country Road, Suite 450, Mineola, NY 11501, USA
| | - George K. Turi
- Division of Immunohistopathology, Department of Pathology, Winthrop-University Hospital, Mineola, NY 11501, USA
| | - Randa Hennawy
- Department of Pathology, Winthrop-University Hospital, Mineola, NY11501, USA
| | - Alexander A. Hindenburg
- Division of Oncology/Hematology, Department of Medicine, Winthrop-University Hospital, 200 Old Country Road, Suite 450, Mineola, NY 11501, USA
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Noh M, Smith JL, Huh YH, Sherley JL. A resource for discovering specific and universal biomarkers for distributed stem cells. PLoS One 2011; 6:e22077. [PMID: 21818293 PMCID: PMC3139609 DOI: 10.1371/journal.pone.0022077] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 06/14/2011] [Indexed: 01/23/2023] Open
Abstract
Specific and universal biomarkers for distributed stem cells (DSCs) have been elusive. A major barrier to discovery of such ideal DSC biomarkers is difficulty in obtaining DSCs in sufficient quantity and purity. To solve this problem, we used cell lines genetically engineered for conditional asymmetric self-renewal, the defining DSC property. In gene microarray analyses, we identified 85 genes whose expression is tightly asymmetric self-renewal associated (ASRA). The ASRA gene signature prescribed DSCs to undergo asymmetric self-renewal to a greater extent than committed progenitor cells, embryonic stem cells, or induced pluripotent stem cells. This delineation has several significant implications. These include: 1) providing experimental evidence that DSCs in vivo undergo asymmetric self-renewal as individual cells; 2) providing an explanation why earlier attempts to define a common gene expression signature for DSCs were unsuccessful; and 3) predicting that some ASRA proteins may be ideal biomarkers for DSCs. Indeed, two ASRA proteins, CXCR6 and BTG2, and two other related self-renewal pattern associated (SRPA) proteins identified in this gene resource, LGR5 and H2A.Z, display unique asymmetric patterns of expression that have a high potential for universal and specific DSC identification.
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Affiliation(s)
- Minsoo Noh
- School of Pharmacy, Ajou University, Suwon, South Korea
| | - Janet L. Smith
- Programs in Regenerative Biology and Cancer Biology, Adult Stem Cell Technology Center, Boston Biomedical Research Institute, Watertown, Massachusetts, United States of America
| | - Yang Hoon Huh
- Programs in Regenerative Biology and Cancer Biology, Adult Stem Cell Technology Center, Boston Biomedical Research Institute, Watertown, Massachusetts, United States of America
| | - James L. Sherley
- Programs in Regenerative Biology and Cancer Biology, Adult Stem Cell Technology Center, Boston Biomedical Research Institute, Watertown, Massachusetts, United States of America
- * E-mail:
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Patra SK, Deb M, Patra A. Molecular marks for epigenetic identification of developmental and cancer stem cells. Clin Epigenetics 2011; 2:27-53. [PMID: 22704268 PMCID: PMC3365374 DOI: 10.1007/s13148-010-0016-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 11/24/2010] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Epigenetic regulations of genes by reversible methylation of DNA (at the carbon-5 of cytosine) and numerous reversible modifications of histones play important roles in normal physiology and development, and epigenetic deregulations are associated with developmental disorders and various disease states, including cancer. Stem cells have the capacity to self-renew indefinitely. Similar to stem cells, some malignant cells have the capacity to divide indefinitely and are referred to as cancer stem cells. In recent times, direct correlation between epigenetic modifications and reprogramming of stem cell and cancer stem cell is emerging. Major discoveries were made with investigations on reprogramming gene products, also known as master regulators of totipotency and inducer of pluoripotency, namely, OCT4, NANOG, cMYC, SOX2, Klf4, and LIN28. The challenge to induce pluripotency is the insertion of four reprogramming genes (Oct4, Sox2, Klf4, and c-Myc) into the genome. There are always risks of silencing of these genes by epigenetic modifications in the host cells, particularly, when introduced through retroviral techniques. In this contribution, we will discuss some of the major discoveries on epigenetic modifications within the chromatin of various genes associated with cancer progression and cancer stem cells in comparison to normal development of stem cell. These modifications may be considered as molecular signatures for predicting disorders of development and for identifying disease states. ELECTRONIC SUPPLEMENTARY MATERIAL The online version of this article (doi:10.1007/s13148-010-0016-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Department of Life Science, National Institute of Technology, Rourkela, Orissa 769008 India
| | - Moonmoon Deb
- Epigenetics and Cancer Research Laboratory, Department of Life Science, National Institute of Technology, Rourkela, Orissa 769008 India
| | - Aditi Patra
- Department of Animal Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal India
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Wolkenhauer O, Shibata DK, Mesarović MD. A stem cell niche dominance theorem. BMC SYSTEMS BIOLOGY 2011; 5:4. [PMID: 21214945 PMCID: PMC3030540 DOI: 10.1186/1752-0509-5-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 01/08/2011] [Indexed: 01/23/2023]
Abstract
Background Multilevelness is a defining characteristic of complex systems. For example, in the intestinal tissue the epithelial lining is organized into crypts that are maintained by a niche of stem cells. The behavior of the system 'as a whole' is considered to emerge from the functioning and interactions of its parts. What we are seeking here is a conceptual framework to demonstrate how the "fate" of intestinal crypts is an emergent property that inherently arises from the complex yet robust underlying biology of stem cells. Results We establish a conceptual framework in which to formalize cross-level principles in the context of tissue organization. To this end we provide a definition for stemness, which is the propensity of a cell lineage to contribute to a tissue fate. We do not consider stemness a property of a cell but link it to the process in which a cell lineage contributes towards tissue (mal)function. We furthermore show that the only logically feasible relationship between the stemness of cell lineages and the emergent fate of their tissue, which satisfies the given criteria, is one of dominance from a particular lineage. Conclusions The dominance theorem, conceived and proven in this paper, provides support for the concepts of niche succession and monoclonal conversion in intestinal crypts as bottom-up relations, while crypt fission is postulated to be a top-down principle.
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Affiliation(s)
- Olaf Wolkenhauer
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany.
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Shoreibah MG, Jackson CL, Price PW, Meagher R, Godwin AK, Cai Q, Gildersleeve JC. Anti-human embryonic stem cell monoclonal antibody Hesca-2 binds to a glycan epitope commonly found on carcinomas. Stem Cells Dev 2010; 20:515-25. [PMID: 20887211 DOI: 10.1089/scd.2010.0172] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hesca-2, a monoclonal antibody (mAb) IgM raised to the human embryonic stem cell (hESC) line BG-01v, binds with high affinity (nM) to the disaccharide epitope (Galβ1-3GlcNAc) on a glycan microarray. This epitope was expressed on pluripotent progenitor hESCs in culture, but not in various differentiated cells derived from hESC based on immunofluorescence microscopy. Hesca-2 stains a limited subset of cells in adult human tissues (eg, esophagus and breast). This mAb also crossreacts in immunofluorescence microscopy studies with several human ovarian cancer cell lines and is cytotoxic to them based on the release of cytosolic enzyme lactate dehydrogenase into the media. Hesca-2 immunohistochemically stained tissue from a number of human tumors, including ovary, breast, colon, and esophageal cancer. These data suggest that Hesca-2 recognizes a surface marker found both in stem cells and certain cancer cells.
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Zhang S, Han Z, Kong Q, Wang J, Sun B, Wang G, Mu L, Wang D, Liu Y, Li H. Malignant transformation of rat bone marrow-derived mesenchymal stem cells treated with 4-nitroquinoline 1-oxide. Chem Biol Interact 2010; 188:119-26. [DOI: 10.1016/j.cbi.2010.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/02/2010] [Accepted: 06/14/2010] [Indexed: 10/19/2022]
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Chegini N. Proinflammatory and profibrotic mediators: principal effectors of leiomyoma development as a fibrotic disorder. Semin Reprod Med 2010; 28:180-203. [PMID: 20414842 DOI: 10.1055/s-0030-1251476] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Leiomyomas are believed to derive from the transformation of myometrial smooth muscle cells/connective tissue fibroblasts. Although the identity of the molecule(s) that initiate such cellular transformation and orchestrate subsequent growth is still unknown, conventional evidence indicates that ovarian steroids are essential for leiomyoma growth. Ovarian steroid action in their target cell/tissue is mediated in part through local expression of various growth factors, cytokines, and chemokines. These autocrine/paracrine molecules with proinflammatory and profibrotic activities serve as major contributing factors in regulating cellular transformation, cell growth and apoptosis, angiogenesis, cellular hypertrophy, and excess tissue turnover, events central to leiomyoma growth. This review addresses the key regulatory functions of proinflammatory and profibrotic mediators and their molecular mechanisms, downstream signaling that regulates cellular events that result in transformation, and commitments of specific cells into forming a cellular environment with a possible role in development and subsequent growth of leiomyomas.
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Affiliation(s)
- Nasser Chegini
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Florida, Gainesville, Florida 32610, USA.
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Hemmings C. The elaboration of a critical framework for understanding cancer: the cancer stem cell hypothesis. Pathology 2010; 42:105-12. [PMID: 20085510 DOI: 10.3109/00313020903488773] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The cancer stem cell hypothesis suggests that malignant tumours may arise from a limited number of specialised cells possessing the key 'stem' properties of self-renewal and the ability to produce differentiated progeny. Such cells purportedly constitute a small fraction of most tumours but have greater potential to produce new tumours than their 'non-stem' counterparts. However, they have proven difficult to identify and characterise in most malignancies. Cancer stem cells are liable to be resistant to most forms of conventional chemotherapy and radiation and so may help to explain tumour recurrence after a seemingly good response to initial therapy. This review examines the evidence for the existence of such cells, the therapeutic implications of this hypothesis, and problems posed by it, as well as outlining the concept of the stem cell niche and its possible role in tumour development and progression.
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Affiliation(s)
- Chris Hemmings
- ACT Pathology at The Canberra Hospital, Canberra, Australian Capital Territory, and School of Surgery, University of Western Australia, Perth, Western Australia, Australia.
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Panteleakou Z, Lembessis P, Sourla A, Pissimissis N, Polyzos A, Deliveliotis C, Koutsilieris M. Detection of circulating tumor cells in prostate cancer patients: methodological pitfalls and clinical relevance. Mol Med 2008; 15:101-14. [PMID: 19081770 DOI: 10.2119/molmed.2008.00116] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 11/26/2008] [Indexed: 12/14/2022] Open
Abstract
Disseminated malignancy is the major cause of prostate cancer-related mortality. Circulating tumor cells (CTCs) are essential for the establishment of metastasis. Various contemporary and molecular methods using prostate-specific biomarkers have been applied to detect extraprostatic disease that is undetectable by conventional imaging techniques, assessing the risk for disease recurrence after therapy of curative intent. However, the clinical relevance of CTC detection is still controversial. We review current literature regarding molecular methods used for the detection of CTCs in the peripheral blood and bone marrow biopsies of patients with prostate cancer, and we discuss the methodological pitfalls that influence the clinical significance of molecular staging.
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Affiliation(s)
- Zacharoula Panteleakou
- Department of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, Goudi-Athens, Greece
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Berry NB, Bapat SA. Ovarian cancer plasticity and epigenomics in the acquisition of a stem-like phenotype. J Ovarian Res 2008; 1:8. [PMID: 19025622 PMCID: PMC2612659 DOI: 10.1186/1757-2215-1-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 11/24/2008] [Indexed: 02/07/2023] Open
Abstract
Aggressive epithelial ovarian cancer (EOC) is genetically and epigenetically distinct from normal ovarian surface epithelial cells (OSE) and early neoplasia. Co-expression of epithelial and mesenchymal markers in EOC suggests an involvement of epithelial-mesenchymal transition (EMT) in cancer initiation and progression. This phenomenon is often associated with acquisition of a stem cell-like phenotype and chemoresistance that correlate with the specific gene expression patterns accompanying transformation, revealing a plasticity of the ovarian cancer cell genome during disease progression.Differential gene expressions between normal and transformed cells reflect the varying mechanisms of regulation including genetic changes like rearrangements within the genome, as well as epigenetic changes such as global genomic hypomethylation with localized promoter CpG island hypermethylation. The similarity of gene expression between ovarian cancer cells and the stem-like ovarian cancer initiating cells (OCIC) are surprisingly also correlated with epigenetic mechanisms of gene regulation in normal stem cells. Both normal and cancer stem cells maintain genetic flexibility by co-placement of activating and/or repressive epigenetic modifications on histone H3. The co-occupancy of such opposing histone marks is believed to maintain gene flexibility and such bivalent histones have been described as being poised for transcriptional activation or epigenetic silencing. The involvement of both-microRNA (miRNA) mediated epigenetic regulation, as well as epigenetic-induced changes in miRNA expression further highlight an additional complexity in cancer stem cell epigenomics.Recent advances in array-based whole-genome/epigenome analyses will continue to further unravel the genomes and epigenomes of cancer and cancer stem cells. In order to illuminate phenotypic signatures that delineate ovarian cancer from their associated cancer stem cells, a priority must lie in the expansion of current technologies and further implementation of bioinformatics to handle the complexity of the cancer epigenome and the various networks that coordinate disease initiation and progression. Great potential lies in the translation of these findings into epigenetic-based therapies. Additionally, targeting chemo-resistant cancer stem cells may provide a much needed breakthrough in treatment of advanced ovarian cancer and chemoresistant disease.
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Affiliation(s)
- Nicholas B Berry
- National Centre for Cell Science, NCCS Complex, Pune University Campus, Pune 411007, INDIA
| | - Sharmila A Bapat
- National Centre for Cell Science, NCCS Complex, Pune University Campus, Pune 411007, INDIA
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Kakarala M, Wicha MS. Implications of the cancer stem-cell hypothesis for breast cancer prevention and therapy. J Clin Oncol 2008; 26:2813-20. [PMID: 18539959 DOI: 10.1200/jco.2008.16.3931] [Citation(s) in RCA: 312] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Recent research in breast biology has provided support for the cancer stem-cell hypothesis. Two important components of this hypothesis are that tumors originate in mammary stem or progenitor cells as a result of dysregulation of the normally tightly regulated process of self-renewal. As a result, tumors contain and are driven by a cellular subcomponent that retains key stem-cell properties including self-renewal, which drives tumorigenesis and differentiation that contributes to cellular heterogeneity. Advances in stem-cell technology have led to the identification of stem cells in normal and malignant breast tissue. The study of these stem cells has helped to elucidate the origin of the molecular complexity of human breast cancer. The cancer stem-cell hypothesis has important implications for early detection, prevention, and treatment of breast cancer. Both hereditary and sporadic breast cancers may develop through dysregulation of stem-cell self-renewal pathways. These aberrant stem cells may provide targets for the development of cancer prevention strategies. Furthermore, because breast cancer stem cells may be highly resistant to radiation and chemotherapy, the development of more effective therapies for this disease may require the effective targeting of this cell population.
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Affiliation(s)
- Madhuri Kakarala
- University of Michigan Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109-5942, USA
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Abstract
There is increasing evidence suggesting that stem cells are susceptive to carcinogenesis and, consequently, can be the origin of many cancers. Recently, the neoplastic potential of stem cells has been supported by many groups showing the existence of subpopulations with stem cell characteristics in tumor biopsies such as brain and breast. Evidence supporting the cancer stem cell hypothesis has gained impact due to progress in stem cell biology and development of new models to validate the self-renewal potential of stem cells. Recent evidence on the possible identification of cancer stem cells may offer an opportunity to use these cells as future therapeutic targets. Therefore, model systems in this field have become very important and useful. This review will focus on the state of knowledge on cancer stem cell research, including cell line models for cancer stem cells. The latter will, as models, help us both in the identification and characterization of cancer stem cells and in the further development of therapeutic strategies including tissue engineering.
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Affiliation(s)
- Nedime Serakinci
- Southern Denmark University, Institute for Regional Health Research (IRS), Telomere and Aging Group, Biopark Vejle, Tysklandsvej 77100 Vejle, Denmark.
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31
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Wu XZ. Origin of cancer stem cells: the role of self-renewal and differentiation. Ann Surg Oncol 2007; 15:407-14. [PMID: 18043974 DOI: 10.1245/s10434-007-9695-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/24/2007] [Accepted: 10/19/2007] [Indexed: 12/12/2022]
Abstract
BACKGROUND Self-renewal and differentiation potential is the feature of stem cells. Differentiation is usually considered to be a one-way process of specialization as cells develop the functions of their ultimate fate and lose their immature characteristics, such as self-renewal. Progenitor cells, the products of stem cells losing the activity of self-renewal, could differentiate to mature cells, which have the feature of differentiation and lose the activity of self-renewal. The roles for cancer stem cells have been demonstrated for some cancers. However, the origin of the cancer stem cells remains elusive. METHODS This review focuses on current scientific controversies related to the establishment of the cancer stem cells--in particular, how self-renewal and differentiation block might contribute to the evolution of cancer. RESULTS Cancer stem cells may be caused by transforming mutations occurring in multi-potential stem cells, tissue-specific stem cells, progenitor cells, mature cells and cancer cells. Progenitor cells obtain the self-renewal activity by activating the self-renewal-associated genes rather than dedifferentiate to tissue special stem cells. The transform multi-potential stem cells gain the differentiation feature of special tissue by differentiating to cancer cells. Mature cells and cancer cells may dedifferentiate or reprogram to cancer stem cells by genetic and / or epigenetic events to gain the self-renewal activity and lose some features of differentiation. The cancer-derived stem cells are not the "cause", but the "consequence" of carcinogenesis. The genetic program controlling self-renewal and differentiation is a key unresolved issue. CONCLUSION Cancer stem cells may be caused by disturbance of self-renewal and differentiation occurring in multi-potential stem cells, tissue-specific stem cells, progenitor cells, mature cells and cancer cells.
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Affiliation(s)
- Xiong-Zhi Wu
- Tianjin Medical University Cancer Institute and Hospital, Ti-Yuan-Bei, Huan-Hu-Xi Road, He-Xi District, Tianjin 300060, China.
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