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Chen X, Adhikary G, Newland JJ, Xu W, Keillor JW, Weber DJ, Eckert RL. Transglutaminase 2 Binds to the CD44v6 Cytoplasmic Domain to Stimulate CD44v6/ERK1/2 Signaling and Maintain an Aggressive Cancer Phenotype. Mol Cancer Res 2023; 21:922-932. [PMID: 37227250 DOI: 10.1158/1541-7786.mcr-23-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/08/2023] [Accepted: 05/24/2023] [Indexed: 05/26/2023]
Abstract
Transglutaminase 2 (TG2) is a key cancer cell survival protein in many cancer types. As such, efforts are underway to characterize the mechanism of TG2 action. In this study, we report that TG2 stimulates CD44v6 activity to enhance cancer cell survival via a mechanism that involves formation of a TG2/CD44v6/ERK1/2 complex that activates ERK1/2 signaling to drive an aggressive cancer phenotype. TG2 and ERK1/2 bind to the CD44v6 C-terminal intracellular cytoplasmic domain to activate ERK1/2 and stimulate cell proliferation and invasion. This is the same region that binds to ERM proteins and ankyrin to activate CD44v6-dependent cell proliferation, invasion, and migration. We further show that treatment with hyaluronan (HA), the physiologic CD44v6 ligand, stimulates CD44v6 activity, as measured by ERK1/2 activation, but that this response is severely attenuated in TG2 or CD44v6 knockdown or knockout cells. Moreover, treatment with TG2 inhibitor reduces tumor growth and that is associated with reduced CD44v6 level and ERK1/2 activity, and reduced stemness and epithelial-mesenchymal transition (EMT). These changes are replicated in CD44v6 knockout cells. These findings suggest that a unique TG2/CD44v6/ERK1/2 complex leads to increased ERK1/2 activity to stimulate an aggressive cancer phenotype and stimulate tumor growth. These findings have important implications for cancer stem cell maintenance and suggest that cotargeting of TG2 and CD44v6 with specific inhibitors may be an effective anticancer treatment strategy. IMPLICATIONS TG2 and CD44v6 are important procancer proteins. TG2 and ERK1/2 bind to the CD44v6 C-terminal domain to form a TG2/CD44v6/ERK1/2 complex that activates ERK1/2 to stimulate the cancer phenotype.
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Affiliation(s)
- Xi Chen
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gautam Adhikary
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - John J Newland
- Department of Surgery Division of Thoracic Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Wen Xu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jeffrey W Keillor
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - David J Weber
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, Maryland
| | - Richard L Eckert
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, Maryland
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Chen X, Adhikary G, Ma E, Newland JJ, Naselsky W, Xu W, Eckert RL. Sulforaphane inhibits CD44v6/YAP1/TEAD signaling to suppress the cancer phenotype. Mol Carcinog 2023; 62:236-248. [PMID: 36285644 PMCID: PMC9851963 DOI: 10.1002/mc.23479] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 01/25/2023]
Abstract
Sulforaphane (SFN) is a promising cancer prevention and treatment agent that strongly suppresses the cutaneous squamous cell carcinoma (CSCC) cell cancer phenotype. We previously showed that yes-associated protein 1 (YAP1)/TEAD signaling is a key procancer stimulator of the aggressive CSCC cell cancer phenotype. However, SFN-responsive upstream regulators of YAP1/TEAD signaling are not well characterized and so there is a pressing need to identify these factors. We show that CD44v6 knockdown reduces YAP1/TEAD-dependent transcription and target gene expression, and that this is associated with reduced spheroid formation, invasion and migration. CD44v6 knockout cell lines also display reduced YAP1/TEAD activity and target gene expression and attenuated spheroid formation, invasion, migration and tumor formation. An important finding is that SFN treatment suppresses CD44v6 level leading to a reduction in YAP1/TEAD signaling and marker gene expression. Sox2 level and epithelial-mesenchymal transition (EMT) are also reduced. Forced expression of constitutive active YAP1 in CD44v6 knockdown cells partially restores the aggressive cancer phenotype. These important findings suggest that CD44v6 drives YAP1/TEAD signaling to enhance the CSCC cell cancer phenotype and that SFN treatment reduces CD44v6 level/function which, in turn, reduces YAP1/TEAD signaling leading to reduced stemness, EMT and tumor growth.
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Affiliation(s)
- Xi Chen
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gautam Adhikary
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Emily Ma
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - John J. Newland
- Department of Surgery Division of Thoracic Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Warren Naselsky
- Department of Surgery Division of Thoracic Oncology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Wen Xu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Richard L. Eckert
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland
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Grandi F, Miot HA, Rocha RM, Gomes CMS, Queiroz‐Hazarbassanov N, Montoya‐Florez LM, Cogliati B, Rocha NS. Immunophenotypic and molecular profile of cancer stem‐cell markers in ex vivo canine transmissible venereal tumour (CTVT). Vet Med Sci 2022; 8:2297-2306. [DOI: 10.1002/vms3.828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Fabrizio Grandi
- Department of Pathology, Botucatu Medical School Universidade Estadual Paulista, UNESP Botucatu São Paulo Brazil
| | - Hélio Amante Miot
- Department of Dermatology and Radiotherapy Botucatu Medical School Universidade Estadual Paulista, UNESP Botucatu São Paulo Brazil
| | | | | | | | | | - Bruno Cogliati
- Department of Pathology School of Veterinary Medicine and Animal Science University of Sao Paulo São Paulo Brazil
| | - Noeme Sousa Rocha
- Department of Pathology, Botucatu Medical School Universidade Estadual Paulista, UNESP Botucatu São Paulo Brazil
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Evrard C, Lambert de Rouvroit C, Poumay Y. Epidermal Hyaluronan in Barrier Alteration-Related Disease. Cells 2021; 10:3096. [PMID: 34831319 PMCID: PMC8618819 DOI: 10.3390/cells10113096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 12/13/2022] Open
Abstract
In skin, although the extracellular matrix (ECM) is highly developed in dermis and hypodermis, discrete intercellular spaces between cells of the living epidermal layers are also filled with ECM components. Herein, we review knowledge about structure, localization and role of epidermal hyaluronan (HA), a key ECM molecule. HA is a non-sulfated glycosaminoglycan non-covalently bound to proteins or lipids. Components of the basal lamina maintain some segregation between the epidermis and the underlying dermis, and all epidermal HA is locally synthesized and degraded. Functions of HA in keratinocyte proliferation and differentiation are still controversial. However, through interactions with partners, such as the TSG-6 protein, HA is involved in the formation, organization and stabilization of the epidermal ECM. In addition, epidermal HA is involved in the formation of an efficient epidermal barrier made of cornified keratinocytes. In atopic dermatitis (AD) with profuse alterations of the epidermal barrier, HA is produced in larger amounts by keratinocytes than in normal skin. Epidermal HA inside AD lesional skin is located in enlarged intercellular spaces, likely as the result of disease-related modifications of HA metabolism.
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Affiliation(s)
| | | | - Yves Poumay
- Research Unit for Molecular Physiology (URPhyM), Department of Medicine, Namur Research Institute for Life Sciences (NARILIS), University of Namur, B-5000 Namur, Belgium; (C.E.); (C.L.d.R.)
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The Molecular Basis of Different Approaches for the Study of Cancer Stem Cells and the Advantages and Disadvantages of a Three-Dimensional Culture. Molecules 2021; 26:molecules26092615. [PMID: 33947095 PMCID: PMC8124970 DOI: 10.3390/molecules26092615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/13/2021] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
Cancer stem cells (CSCs) are a rare tumor subpopulation with high differentiation, proliferative and tumorigenic potential compared to the remaining tumor population. CSCs were first discovered by Bonnet and Dick in 1997 in acute myeloid leukemia. The identification and isolation of these cells in this pioneering study were carried out through the flow cytometry, exploiting the presence of specific cell surface molecular markers (CD34+/CD38−). In the following years, different strategies and projects have been developed for the study of CSCs, which are basically divided into surface markers assays and functional assays; some of these techniques also allow working with a cellular model that better mimics the tumor architecture. The purpose of this mini review is to summarize and briefly describe all the current methods used for the identification, isolation and enrichment of CSCs, describing, where possible, the molecular basis, the advantages and disadvantages of each technique with a particular focus on those that offer a three-dimensional culture.
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Chen L, Fu C, Zhang Q, He C, Zhang F, Wei Q. The role of CD44 in pathological angiogenesis. FASEB J 2020; 34:13125-13139. [PMID: 32830349 DOI: 10.1096/fj.202000380rr] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023]
Abstract
Angiogenesis is required for normal development and occurs as a pathological step in a variety of disease settings, such as cancer, ocular diseases, and ischemia. Recent studies have revealed the role of CD44, a widely expressed cell surface adhesion molecule, in promoting pathological angiogenesis and the development of its associated diseases through its regulation of diverse function of endothelial cells, such as proliferation, migration, adhesion, invasion, and communication with the microenvironment. Conversely, the absence of CD44 expression or inhibition of its function impairs pathological angiogenesis and disease progression. Here, we summarize the current understanding of the roles of CD44 in pathological angiogenesis and the underlying cellular and molecular mechanisms.
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Affiliation(s)
- Li Chen
- Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P.R. China.,Key Laboratory of Rehabilitation Medicine in Sichuan Province, West China Hospital, Sichuan University, Chengdu, P.R. China.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Chenying Fu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Qing Zhang
- Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P.R. China.,Key Laboratory of Rehabilitation Medicine in Sichuan Province, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Chengqi He
- Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P.R. China.,Key Laboratory of Rehabilitation Medicine in Sichuan Province, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Feng Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Quan Wei
- Department of Rehabilitation Medicine Center, West China Hospital, Sichuan University, Chengdu, P.R. China.,Key Laboratory of Rehabilitation Medicine in Sichuan Province, West China Hospital, Sichuan University, Chengdu, P.R. China
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Kleiser S, Nyström A. Interplay between Cell-Surface Receptors and Extracellular Matrix in Skin. Biomolecules 2020; 10:E1170. [PMID: 32796709 PMCID: PMC7465455 DOI: 10.3390/biom10081170] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/01/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
Skin consists of the epidermis and dermis, which are connected by a specialized basement membrane-the epidermal basement membrane. Both the epidermal basement membrane and the underlying interstitial extracellular matrix (ECM) created by dermal fibroblasts contain distinct network-forming macromolecules. These matrices play various roles in order to maintain skin homeostasis and integrity. Within this complex interplay of cells and matrices, cell surface receptors play essential roles not only for inside-out and outside-in signaling, but also for establishing mechanical and biochemical properties of skin. Already minor modulations of this multifactorial cross-talk can lead to severe and systemic diseases. In this review, major epidermal and dermal cell surface receptors will be addressed with respect to their interactions with matrix components as well as their roles in fibrotic, inflammatory or tumorigenic skin diseases.
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Affiliation(s)
- Svenja Kleiser
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Hauptstraße 7, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
| | - Alexander Nyström
- Department of Dermatology, Faculty of Medicine and Medical Center, University of Freiburg, Hauptstraße 7, 79104 Freiburg, Germany
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Lugović-Mihić L, Novak-Bilić G, Vučić M, Japundžić I, Bukvić I. CD44 expression in human skin: High expression in irritant and allergic contact dermatitis and moderate expression in psoriasis lesions in comparison with healthy controls. Contact Dermatitis 2020; 82:297-306. [PMID: 31900953 DOI: 10.1111/cod.13463] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/05/2019] [Accepted: 01/02/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Previous research using animal models demonstrated that CD44 expression may contribute to directing inflammatory cells into skin lesions during inflammation development in allergic contact dermatitis (ACD). OBJECTIVES To examine CD44 expression in patients with ACD and irritant contact dermatitis (ICD), and to compare it to patients with psoriatic lesions and healthy controls' (HCs) skin. METHODS This study included 200 patients comprising four groups of 50 each: ACD, ICD, psoriasis vulgaris, and HCs. CD44 expression was determined by immunohistochemical analysis using an optical microscope, and the results were visualized semiquantitatively by determining the percentage of immunoreactive cells in the epidermis, dermis, and on lymphocytes. RESULTS The highest CD44 expression was found in ICD, followed by ACD, psoriasis vulgaris, and lastly, the HCs (P < .001). Epidermal CD44 expression was significantly higher in contact dermatoses (especially in ICD) compared with psoriasis and healthy skin (P < .001). Similarly, CD44 expression in the dermis and on lymphocytes was strongest in ICD, although less pronounced than in the epidermis. CONCLUSIONS Because significantly elevated CD44 expression in ICD might be related to its function in maintaining and preserving the skin barrier in affected patients, further research on disease pathogenesis and new treatment options is needed.
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Affiliation(s)
- Liborija Lugović-Mihić
- Department of Dermatovenereology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Gaby Novak-Bilić
- Department of Dermatovenereology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Majda Vučić
- Department of Pathology Ljudevit Jurak, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Iva Japundžić
- Department of Dermatovenereology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Iva Bukvić
- Department of Dermatovenereology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
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Moreira IB, Pinto F, Gomes C, Campos D, Reis CA. Impact of Truncated O-glycans in Gastric-Cancer-Associated CD44v9 Detection. Cells 2020; 9:cells9020264. [PMID: 31973075 PMCID: PMC7072479 DOI: 10.3390/cells9020264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 02/06/2023] Open
Abstract
CD44 variant isoforms are often upregulated in cancer and associated with increased aggressive tumor phenotypes. The CD44v9 is one of the major protein splice variant isoforms expressed in human gastrointestinal cancer cells. Immunodetection of CD44 isoforms like CD44v9 in tumor tissue is almost exclusively performed by using specific monoclonal antibodies. However, the structural variability conferred by both the alternative splicing and CD44 protein glycosylation is disregarded. In the present work, we have evaluated the role of O-glycosylation using glycoengineered gastric cancer models in the detection of CD44v9 by monoclonal antibodies. We demonstrated, using different technical approaches, that the presence of immature O-glycan structures, such as Tn and STn, enhance CD44v9 protein detection. These findings can have significant implications in clinical applications mainly at the detection and targeting of this cancer-related CD44v9 isoform and highlight the utmost importance of considering glycan structures in cancer biomarker detection and in therapy targeting.
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Affiliation(s)
- Inês B. Moreira
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Filipe Pinto
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Catarina Gomes
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Diana Campos
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
- Correspondence: (D.C.); (C.A.R.)
| | - Celso A. Reis
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
- Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- Correspondence: (D.C.); (C.A.R.)
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Overexpression of CD44 Variant 9: A Novel Cancer Stem Cell Marker in Human Cholangiocarcinoma in Relation to Inflammation. Mediators Inflamm 2018; 2018:4867234. [PMID: 30402042 PMCID: PMC6198546 DOI: 10.1155/2018/4867234] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/29/2018] [Accepted: 09/09/2018] [Indexed: 12/15/2022] Open
Abstract
Various CD44 isoforms are expressed in several cancer stem cells during tumor progression and metastasis. In particular, CD44 variant 9 (CD44v9) is highly expressed in chronic inflammation-induced cancer. We investigated the expression of CD44v9 and assessed whether CD44v9 is a selective biomarker of human cholangiocarcinoma (CCA). The expression profile of CD44v9 was evaluated in human liver fluke Opisthorchis viverrini-related CCA (OV-CCA) tissues, human CCA (independent of OV infection, non-OV-CCA) tissues, and normal liver tissues. CD44v9 overexpression was detected by immunohistochemistry (IHC) in CCA tissues. There was a higher level of CD44v9 expression and IHC score in OV-CCA tissues than in non-OV-CCA tissues, and there was no CD44v9 staining in the bile duct cells of normal liver tissues. In addition, we observed significantly higher expression of inflammation-related markers, such as S100P and COX-2, in OV-CCA tissues compared to that in non-OV and normal liver tissues. Thus, these findings suggest that CD44v9 may be a novel candidate CCA stem cell marker and may be related to inflammation-associated cancer development.
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Parte SC, Smolenkov A, Batra SK, Ratajczak MZ, Kakar SS. Ovarian Cancer Stem Cells: Unraveling a Germline Connection. Stem Cells Dev 2017; 26:1781-1803. [PMID: 29078734 PMCID: PMC5725638 DOI: 10.1089/scd.2017.0153] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022] Open
Abstract
Ovarian cancer is most lethal among gynecological cancers with often fatal consequences due to lack of effective biomarkers and relapse, which propels ovarian cancer research into unique directions to establish solid targeted therapeutics. "Ovarian stem cells" expressing germline pluripotent markers serve as novel paradigm with potential to address infertility, menopause, and probably influence tumor initiation. Cancer stem cells (CSCs) pose vital role in tumor recurrence and hence it is extremely important to study them with respect to ovarian stem cells across various cancer stages and normal ovaries. Pluripotent (OCT4, NANOG, SOX2, SSEA1, and SSEA4), germline (IFITM3, VASA/DDX4), and cancer stem (CD44, LGR5) cell specific markers were characterized for protein and mRNA expression in tumor tissues to understand their distribution in the surface epithelium and ovarian cortex in benign, borderline, and high-grade malignant stages. To elucidate whether pluripotent ovarian germline stem cells and CSCs are common subset of stem cells in tumor tissues, VASA was colocalized with known pluripotent stem (OCT4, SSEA1, SSEA4) and CSC (CD44, LGR5) specific markers by confocal microscopy. Single, smaller spherical (≤5 μm), and larger elliptical fibroblast like (≥10 μm) cells (also in clusters or multiples) were detected implying probable functional behavioral significance of cells in tumor initiation and metastasis across various cancer stages. Cells revealed characteristic staining pattern in ovarian surface epithelium (OSE) and cortex regions exclusive for each marker. Co-expression studies revealed specific subpopulations existing simultaneously in OSE and cortex and that a dynamic hierarchy of (cancer) stem cells with germline properties prevails in normal ovaries and cancer stages. Novel insights into CSC biology with respect to ovarian and germline stem cell perspective were obtained. Understanding molecular signatures and distribution within ovarian tissue may enable identification of precise tumor-initiating CSC populations and signaling pathways thus improving their efficient targeting and strategies to prevent their dissemination causing fatal relapse.
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Affiliation(s)
- Seema C. Parte
- Department of Physiology, University of Louisville, Louisville, Kentucky
- James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
| | - Andrei Smolenkov
- James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Mariusz Z. Ratajczak
- James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
- Department of Medicine, University of Louisville, Louisville, Kentucky
| | - Sham S. Kakar
- Department of Physiology, University of Louisville, Louisville, Kentucky
- James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
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