101
|
The “good-cop bad-cop” TGF-beta role in breast cancer modulated by non-coding RNAs. Biochim Biophys Acta Gen Subj 2017; 1861:1661-1675. [DOI: 10.1016/j.bbagen.2017.04.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/08/2017] [Accepted: 04/10/2017] [Indexed: 02/07/2023]
|
102
|
Hepatocyte Growth Factor, a Key Tumor-Promoting Factor in the Tumor Microenvironment. Cancers (Basel) 2017; 9:cancers9040035. [PMID: 28420162 PMCID: PMC5406710 DOI: 10.3390/cancers9040035] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/05/2017] [Accepted: 04/13/2017] [Indexed: 01/13/2023] Open
Abstract
The tumor microenvironment plays a key role in tumor development and progression. Stromal cells secrete growth factors, cytokines and extracellular matrix proteins which promote growth, survival and metastatic spread of cancer cells. Fibroblasts are the predominant constituent of the tumor stroma and Hepatocyte Growth Factor (HGF), the specific ligand for the tyrosine kinase receptor c-MET, is a major component of their secretome. Indeed, cancer-associated fibroblasts have been shown to promote growth, survival and migration of cancer cells in an HGF-dependent manner. Fibroblasts also confer resistance to anti-cancer therapy through HGF-induced epithelial mesenchymal transition (EMT) and activation of pro-survival signaling pathways such as ERK and AKT in tumor cells. Constitutive HGF/MET signaling in cancer cells is associated with increased tumor aggressiveness and predicts poor outcome in cancer patients. Due to its role in tumor progression and therapeutic resistance, both HGF and MET have emerged as valid therapeutic targets. Several inhibitors of MET and HGF are currently being tested in clinical trials. Preclinical data provide a strong indication that inhibitors of HGF/MET signaling overcome both primary and acquired resistance to EGFR, HER2, and BRAF targeting agents. These findings support the notion that co-targeting of cancer cells and stromal cells is required to prevent therapeutic resistance and to increase the overall survival rate of cancer patients. HGF dependence has emerged as a hallmark of therapeutic resistance, suggesting that inhibitors of biological activity of HGF should be included into therapeutic regimens of cancer patients.
Collapse
|
103
|
Wang B, Chen Q, Cao Y, Ma X, Yin C, Jia Y, Zang A, Fan W. LGR5 Is a Gastric Cancer Stem Cell Marker Associated with Stemness and the EMT Signature Genes NANOG, NANOGP8, PRRX1, TWIST1, and BMI1. PLoS One 2016; 11:e0168904. [PMID: 28033430 PMCID: PMC5199039 DOI: 10.1371/journal.pone.0168904] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/05/2016] [Indexed: 12/31/2022] Open
Abstract
Background Accumulating evidence supports the hypothesis that cancer stem cells (CSCs) are essential for cancer initiation, metastasis and drug resistance. However, the functional association of gastric CSC markers with stemness and epithelial-mesenchymal transition (EMT) signature genes is unclear. Methods qPCR was performed to measure the expression profiles of stemness and EMT signature genes and their association with putative CSC markers in gastric cancer tissues, cancer cell lines and sphere cells. Western blot analysis was used to confirm the results of the transcript analysis. Cell proliferation, cell migration, drug resistance and sphere cell growth assays were conducted to measure the expansion and invasion abilities of the cells. Tumor xenograft experiments were performed in NOD/SCID mice to test cell stemness in vivo. Flow cytometry and immunofluorescence staining were used to analyze cell subpopulations. Results The expression of LGR5 was strikingly up-regulated in sphere cells but not in cancer tissues or parental adherent cells. The up-regulation of LGR5 was also positively associated with stemness regulators (NANOG, OCT4, SOX2, and AICDA) and EMT inducers (PRRX1, TWIST1, and BMI1). In addition, sphere cells exhibited up-regulated vimentin and down-regulated E-cadherin expression. Using gene-specific primers, we found that the NANOG expression primarily originates from the retrogene NANOGP8. Western blot analysis showed that the expression of both LGR5 and NANOG is significantly higher in sphere cells. LGR5 over-expression significantly enhanced sphere cell growth, cell proliferation, cell migration and drug resistance in MGC803 cells. Tumor xenografts in nude mice showed that sphere cells are at least 10 times more efficient at tumor initiation than adherent cells. Flow cytometry analysis showed that ~20% of sphere cells are LGR5+/CD54+, but only ~3% of adherent cells are Lgr5+/CD54+. Immunofluorescence staining supports the above results. Conclusion The LGR5-expressing fraction of CD54+ cells represents gastric cancer CSCs, in which LGR5 is closely associated with stemness and EMT core genes, and NANOG expression is mainly contributed by the retrogene NANOGP8. Sphere cells are the best starting materials for the characterization of CSCs.
Collapse
MESH Headings
- Animals
- Biomarkers, Tumor/deficiency
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Cadherins/genetics
- Carcinogenesis/genetics
- Cell Adhesion
- Cell Line, Tumor
- Cell Movement
- Cell Proliferation
- Cell Transformation, Neoplastic
- Down-Regulation
- Drug Resistance, Neoplasm/genetics
- Epithelial-Mesenchymal Transition/genetics
- Female
- Gene Deletion
- Gene Expression Regulation, Neoplastic
- Homeodomain Proteins/genetics
- Humans
- Mice
- Mitogen-Activated Protein Kinase 7/genetics
- Nanog Homeobox Protein/genetics
- Neoplastic Stem Cells/pathology
- Organoplatinum Compounds/pharmacology
- Oxaliplatin
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Stomach Neoplasms/genetics
- Stomach Neoplasms/metabolism
- Stomach Neoplasms/pathology
- Twist-Related Protein 1/genetics
- Up-Regulation
- Vimentin/genetics
Collapse
Affiliation(s)
- Bei Wang
- Molecular Biology Lab of Gastric Cancer, School of Life Sciences, Hebei University, Baoding, Hebei Province, China
| | - Queting Chen
- Department of Medical Oncology, Affiliated Hospital of Hebei University, Baoding, Hebei Province, China
| | - Yang Cao
- Molecular Biology Lab of Gastric Cancer, School of Life Sciences, Hebei University, Baoding, Hebei Province, China
| | - Xia Ma
- Molecular Biology Lab of Gastric Cancer, School of Life Sciences, Hebei University, Baoding, Hebei Province, China
| | - Chenxing Yin
- Molecular Biology Lab of Gastric Cancer, School of Life Sciences, Hebei University, Baoding, Hebei Province, China
| | - Youchao Jia
- Department of Medical Oncology, Affiliated Hospital of Hebei University, Baoding, Hebei Province, China
| | - Aimin Zang
- Department of Medical Oncology, Affiliated Hospital of Hebei University, Baoding, Hebei Province, China
| | - Wufang Fan
- Molecular Biology Lab of Gastric Cancer, School of Life Sciences, Hebei University, Baoding, Hebei Province, China
- * E-mail:
| |
Collapse
|
104
|
Esparza-López J, Ramos-Elías PA, Castro-Sánchez A, Rocha-Zavaleta L, Escobar-Arriaga E, Zentella-Dehesa A, León-Rodríguez E, Medina-Franco H, Ibarra-Sánchez MDJ. Primary breast cancer cell culture yields intra-tumor heterogeneous subpopulations expressing exclusive patterns of receptor tyrosine kinases. BMC Cancer 2016; 16:740. [PMID: 27645148 PMCID: PMC5028979 DOI: 10.1186/s12885-016-2769-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 09/06/2016] [Indexed: 12/26/2022] Open
Abstract
Background It has become evident that intra-tumor heterogeneity of breast cancer impact on several biological processes such as proliferation, migration, cell death and also might contribute to chemotherapy resistance. The expression of Receptor Tyrosine Kinases (RTKs) has not been analyzed in the context of intra-tumor heterogeneity in a primary breast cancer cell culture. Several subpopulations were isolated from the MBCDF (M serial-breast cancer ductal F line) primary breast cancer cells and were successfully maintained in culture and divided in two groups according to their morphology and RTKs expression pattern, and correlated with biological processes like proliferation, migration, anchorage-independent cell growth, and resistance to cytotoxic chemotherapy drugs and tyrosine kinase inhibitors (TKIs). Methods Subpopulations were isolated from MBCDF primary breast cancer cell culture by limiting dilution. RTKs and hormone receptors were examined by Western blot. Proliferation was measure by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT assay). Cell viability was evaluated by Crystal Violet. Migration was assessed using Boyden chambers. Anchorage-independent cell growth was evaluated by colony formation in soft agar. Results Several subpopulations were isolated from the MBCDF breast cancer cells that were divided into two groups according to their morphology. Analysis of RTKs expression pattern showed that HER1, HER3, c-Met and VEGFR2 were expressed exclusively in cells from group 1, but not in cells from group 2. PDGFR was expressed only in cells from group 2, but not in cells from group 1. HER2, HER4, c-Kit, IGF1-R were expressed in all subpopulations. Biological processes correlated with the RTKs expression pattern. Group 2 subpopulations present the highest rate of cell proliferation, migration and anchorage-independent cell growth. Analysis of susceptibility to chemotherapy drugs and TKIs showed that only Paclitaxel and Imatinib behaved differently between groups. Group 1-cells were resistant to both Paclitaxel and Imatinib. Conclusions We demonstrated that subpopulations from MBCDF primary cell culture could be divided into two groups according to their morphology and a RTKs excluding-expression pattern. The differences observed in RTKs expression correlate with the biological characteristics and chemoresistance of each group. These results suggest that intra-tumor heterogeneity contributes to generate groups of subpopulations with a more aggressive phenotype within the tumor. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2769-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- José Esparza-López
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico
| | - Pier A Ramos-Elías
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico
| | - Andrea Castro-Sánchez
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico
| | - Leticia Rocha-Zavaleta
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, CP 04500, Distrito Federal, Mexico
| | - Elizabeth Escobar-Arriaga
- Hospital Ángeles del Pedregal, Camino a Santa Teresa # 1055, México, CP 10700, Distrito Federal, Mexico
| | - Alejandro Zentella-Dehesa
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico.,Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, CP 04500, Distrito Federal, Mexico
| | - Eucario León-Rodríguez
- Departamento de Hemato-Oncología, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico
| | - Heriberto Medina-Franco
- Departamento de Cirugía, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico
| | - María de Jesus Ibarra-Sánchez
- Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Delegación Tlalpan, CP 14080, Distrito Federal, Mexico.
| |
Collapse
|
105
|
Gong JP, Yang L, Tang JW, Sun P, Hu Q, Qin JW, Xu XM, Sun BC, Tang JH. Overexpression of microRNA-24 increases the sensitivity to paclitaxel in drug-resistant breast carcinoma cell lines via targeting ABCB9. Oncol Lett 2016; 12:3905-3911. [PMID: 27895747 PMCID: PMC5104208 DOI: 10.3892/ol.2016.5139] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/25/2016] [Indexed: 12/12/2022] Open
Abstract
Paclitaxel has been widely used in the treatment of breast cancer. However, the development of drug resistance often increases the failure of chemotherapy. Growing evidence has reported the significant role of microRNAs (miRs) in drug resistance. The present study identified that miR-24 was significantly downregulated in paclitaxel-resistant (PR) breast cancer patients and in MCF-7/PR human breast carcinoma cells, and that overexpression of miR-24 could increase the effect of paclitaxel on drug-resistant breast carcinoma cells. Furthermore, miR-24 could directly bind to the 3′-untranslated region of ATP binding cassette B9 to downregulate its expression, thereby reducing drug transportation and improving the anti-tumor effect of paclitaxel on breast cancer cells. In vivo experiments also demonstrated that overexpression of miR-24 could increase the sensitivity of drug-resistant MCF-7 cells to paclitaxel. In conclusion, the present results suggested a novel function for miR-24 in reducing paclitaxel resistance in breast cancer, which may be of important clinical significance.
Collapse
Affiliation(s)
- Jian-Ping Gong
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| | - Liu Yang
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| | - Jun-Wei Tang
- Liver Transplantation Center of The First Affiliated Hospital and Cancer Center, Nanjing Medical University, Nanjing, Jiangsu 210009, P.R. China
| | - Peng Sun
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
| | - Qing Hu
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| | - Jian-Wei Qin
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| | - Xiao-Ming Xu
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| | - Bei-Cheng Sun
- Liver Transplantation Center of The First Affiliated Hospital and Cancer Center, Nanjing Medical University, Nanjing, Jiangsu 210009, P.R. China
| | - Jin-Hai Tang
- Department of General Surgery and Breast Cancer Center, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009, P.R. China
| |
Collapse
|
106
|
Targeting Epithelial-Mesenchymal Transition (EMT) to Overcome Drug Resistance in Cancer. Molecules 2016; 21:molecules21070965. [PMID: 27455225 PMCID: PMC6273543 DOI: 10.3390/molecules21070965] [Citation(s) in RCA: 518] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 07/16/2016] [Accepted: 07/19/2016] [Indexed: 12/24/2022] Open
Abstract
Epithelial–mesenchymal transition (EMT) is known to play an important role in cancer progression, metastasis and drug resistance. Although there are controversies surrounding the causal relationship between EMT and cancer metastasis, the role of EMT in cancer drug resistance has been increasingly recognized. Numerous EMT-related signaling pathways are involved in drug resistance in cancer cells. Cells undergoing EMT show a feature similar to cancer stem cells (CSCs), such as an increase in drug efflux pumps and anti-apoptotic effects. Therefore, targeting EMT has been considered a novel opportunity to overcome cancer drug resistance. This review describes the mechanism by which EMT contributes to drug resistance in cancer cells and summarizes new advances in research in EMT-associated drug resistance.
Collapse
|
107
|
3,6-dihydroxyflavone suppresses the epithelial-mesenchymal transition in breast cancer cells by inhibiting the Notch signaling pathway. Sci Rep 2016; 6:28858. [PMID: 27345219 PMCID: PMC4921838 DOI: 10.1038/srep28858] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/10/2016] [Indexed: 02/07/2023] Open
Abstract
The epithelial to mesenchymal transition (EMT) is a critical developmental program in cancer stem cell (CSC) maintenance and in cancer metastasis. Here, our study found that 3,6-DHF could effectively inhibit EMT in BC cells in vitro and in vivo. 3,6-DHF effectively inhibits the formation and proliferation of BCSCs, and consequently reduces the tumor-initiating capacity of tumor cells in NOD/SCID mice. Optical in vivo imaging of cancer metastasis showed that 3,6-DHF administration suppresses the lung metastasis of BC cells in vivo. Further studies indicated that 3,6-DHF down-regulates Notch1, NICD, Hes-1 and c-Myc, consequently decreasing the formation of the functional transcriptional unit of NICD-CSL-MAML, causing Notch signaling inactivation in BC cells. Over-expression of Notch1 or inhibition of miR-34a significantly reduced the inhibitory effects of 3,6-DHF on EMT, CSCs, as well as cells migration and invasion in BC cells. These data indicated that 3,6-DHF effectively inhibits EMT and CSCs, as well as cells migration and invasion in BC cells, in which miR-34a-mediated Notch1 down-regulation plays a crucial role.
Collapse
|
108
|
Singh M, Mukundan S, Jaramillo M, Oesterreich S, Sant S. Three-Dimensional Breast Cancer Models Mimic Hallmarks of Size-Induced Tumor Progression. Cancer Res 2016; 76:3732-43. [PMID: 27216179 DOI: 10.1158/0008-5472.can-15-2304] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 03/07/2016] [Indexed: 11/16/2022]
Abstract
Tumor size is strongly correlated with breast cancer metastasis and patient survival. Increased tumor size contributes to hypoxic and metabolic gradients in the solid tumor and to an aggressive tumor phenotype. Thus, it is important to develop three-dimensional (3D) breast tumor models that recapitulate size-induced microenvironmental changes and, consequently, natural tumor progression in real time without the use of artificial culture conditions or gene manipulations. Here, we developed size-controlled multicellular aggregates ("microtumors") of subtype-specific breast cancer cells by using non-adhesive polyethylene glycol dimethacrylate hydrogel microwells of defined sizes (150-600 μm). These 3D microtumor models faithfully represent size-induced microenvironmental changes, such as hypoxic gradients, cellular heterogeneity, and spatial distribution of necrotic/proliferating cells. These microtumors acquire hallmarks of tumor progression in the same cell lines within 6 days. Of note, large microtumors of hormone receptor-positive cells exhibited an aggressive phenotype characterized by collective cell migration and upregulation of mesenchymal markers at mRNA and protein level, which was not observed in small microtumors. Interestingly, triple-negative breast cancer (TNBC) cell lines did not show size-dependent upregulation of mesenchymal markers. In conclusion, size-controlled microtumor models successfully recapitulated clinically observed positive association between tumor size and aggressive phenotype in hormone receptor-positive breast cancer while maintaining clinically proven poor correlation of tumor size with aggressive phenotype in TNBC. Such clinically relevant 3D models generated under controlled experimental conditions can serve as precise preclinical models to study mechanisms involved in breast tumor progression as well as antitumor drug effects as a function of tumor progression. Cancer Res; 76(13); 3732-43. ©2016 AACR.
Collapse
Affiliation(s)
- Manjulata Singh
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shilpaa Mukundan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Maria Jaramillo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Steffi Oesterreich
- Women's Cancer Research Center, Magee-Womens Research Institute, University of Pittsburgh Cancer Institute, School of Medicine, Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Shilpa Sant
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania. Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania. McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
| |
Collapse
|
109
|
Voutsadakis IA. Epithelial-Mesenchymal Transition (EMT) and Regulation of EMT Factors by Steroid Nuclear Receptors in Breast Cancer: A Review and in Silico Investigation. J Clin Med 2016; 5:E11. [PMID: 26797644 PMCID: PMC4730136 DOI: 10.3390/jcm5010011] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 12/23/2015] [Accepted: 12/30/2015] [Indexed: 12/20/2022] Open
Abstract
Steroid Nuclear Receptors (SNRs) are transcription factors of the nuclear receptor super-family. Estrogen Receptor (ERα) is the best-studied and has a seminal role in the clinic both as a prognostic marker but also as a predictor of response to anti-estrogenic therapies. Progesterone Receptor (PR) is also used in the clinic but with a more debatable prognostic role and the role of the four other SNRs, ERβ, Androgen Receptor (AR), Glucocorticoid Receptor (GR) and Mineralocorticoid Receptor (MR), is starting only to be appreciated. ERα, but also to a certain degree the other SNRs, have been reported to be involved in virtually every cancer-enabling process, both promoting and impeding carcinogenesis. Epithelial-Mesenchymal Transition (EMT) and the reverse Mesenchymal Epithelial Transition (MET) are such carcinogenesis-enabling processes with important roles in invasion and metastasis initiation but also establishment of tumor in the metastatic site. EMT is governed by several signal transduction pathways culminating in core transcription factors of the process, such as Snail, Slug, ZEB1 and ZEB2, and Twist, among others. This paper will discuss direct regulation of these core transcription factors by SNRs in breast cancer. Interrogation of publicly available databases for binding sites of SNRs on promoters of core EMT factors will also be included in an attempt to fill gaps where other experimental data are not available.
Collapse
Affiliation(s)
- Ioannis A Voutsadakis
- Division of Medical Oncology, Department of Internal Medicine, Sault Area Hospital, Sault Ste Marie, ON P6B 0A8, Canada.
- Division of Clinical Sciences, Northern Ontario School of Medicine, Sudbury, QC P3E 2C6, Canada.
| |
Collapse
|