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Jiang M, Salari A, Stock C, Nikolovska K, Boedtkjer E, Amiri M, Seidler UE. The electroneutral Na +-HCO 3- cotransporter NBCn1 (SLC4A7) modulates colonic enterocyte pH i, proliferation, and migration. Am J Physiol Cell Physiol 2024; 326:C1625-C1636. [PMID: 38646790 PMCID: PMC11371319 DOI: 10.1152/ajpcell.00079.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/05/2024] [Accepted: 04/06/2024] [Indexed: 04/23/2024]
Abstract
NBCn1 (SLC4A7) is one of the two major Na+-HCO3- cotransporters in the human colonic epithelium, expressed predominantly in the highly proliferating colonocytes at the cryptal base. Increased NBCn1 expression levels are reported in tumors, including colorectal cancer. The study explores its importance for maintenance of the intracellular pH (pHi), as well as the proliferative, adhesive, and migratory behavior of the self-differentiating Caco2BBe colonic tumor cell line. In the self-differentiating Caco2BBe cells, NBCn1 mRNA was highly expressed from the proliferative stage until full differentiation. The downregulation of NBCn1 expression by RNA interference affected proliferation and differentiation and decreased intracellular pH (pHi) of the cells in correlation with the degree of knockdown. In addition, a disturbed cell adhesion and reduced migratory speed were associated with NBCn1 knockdown. Murine colonic Nbcn1-/- enteroids also displayed reduced proliferative activity. In the migrating Caco2BBe cells, NBCn1 was found at the leading edge and in colocalization with the focal adhesion markers vinculin and paxillin, which suggests that NBCn1 is involved in the establishment of cell-matrix adhesion. Our data highlight the physiological significance of NBCn1 in modulating epithelial pH homeostasis and cell-matrix interactions in the proliferative region of the colonic epithelium and unravel the molecular mechanism behind pathological overexpression of this transporter in human colorectal cancers.NEW & NOTEWORTHY The transporter NBCn1 plays a central role in maintaining homeostasis within Caco2BBe colonic epithelial cells through its regulation of intracellular pH, matrix adhesion, migration, and proliferation. These observations yield valuable insights into the molecular mechanism of the aberrant upregulation of this transporter in human colorectal cancers.
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Affiliation(s)
- Min Jiang
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Azam Salari
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Christian Stock
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Katerina Nikolovska
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Mahdi Amiri
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Ursula E Seidler
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Hannover, Germany
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2
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Pedersen SHF. Acid-base transporters in the context of tumor heterogeneity. Pflugers Arch 2024; 476:689-701. [PMID: 38332178 DOI: 10.1007/s00424-024-02918-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/20/2024] [Accepted: 01/29/2024] [Indexed: 02/10/2024]
Abstract
The copious metabolic acid production and -extrusion by cancer cells render poorly vascularized regions of solid tumors highly acidic. A growing list of proton - and bicarbonate transporters has been suggested to contribute to net acid extrusion from cancer cells, and/or been shown to be dysregulated and favor malignant development in various cancers. The great majority of these roles have been studied at the level of the cancer cells. However, recent advances in understanding of the cellular and physicochemical heterogeneity of solid tumors both enable and necessitate a reexamination of the regulation and roles of acid-base transporters in such malignancies. This review will briefly summarize the state-of-the-art, with a focus on the SLC9A and SLC4A families, for which most evidence is available. This is followed by a discussion of key concepts and open questions arising from recent insights and of the challenges that need to be tackled to address them. Finally, opportunities and challenges in therapeutic targeting of the acid-base transportome in cancers will be addressed.
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Affiliation(s)
- Stine Helene Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.
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3
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Alsheikh AJ, Wollenhaupt S, King EA, Reeb J, Ghosh S, Stolzenburg LR, Tamim S, Lazar J, Davis JW, Jacob HJ. The landscape of GWAS validation; systematic review identifying 309 validated non-coding variants across 130 human diseases. BMC Med Genomics 2022; 15:74. [PMID: 35365203 PMCID: PMC8973751 DOI: 10.1186/s12920-022-01216-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/17/2022] [Indexed: 02/08/2023] Open
Abstract
Background The remarkable growth of genome-wide association studies (GWAS) has created a critical need to experimentally validate the disease-associated variants, 90% of which involve non-coding variants. Methods To determine how the field is addressing this urgent need, we performed a comprehensive literature review identifying 36,676 articles. These were reduced to 1454 articles through a set of filters using natural language processing and ontology-based text-mining. This was followed by manual curation and cross-referencing against the GWAS catalog, yielding a final set of 286 articles. Results We identified 309 experimentally validated non-coding GWAS variants, regulating 252 genes across 130 human disease traits. These variants covered a variety of regulatory mechanisms. Interestingly, 70% (215/309) acted through cis-regulatory elements, with the remaining through promoters (22%, 70/309) or non-coding RNAs (8%, 24/309). Several validation approaches were utilized in these studies, including gene expression (n = 272), transcription factor binding (n = 175), reporter assays (n = 171), in vivo models (n = 104), genome editing (n = 96) and chromatin interaction (n = 33). Conclusions This review of the literature is the first to systematically evaluate the status and the landscape of experimentation being used to validate non-coding GWAS-identified variants. Our results clearly underscore the multifaceted approach needed for experimental validation, have practical implications on variant prioritization and considerations of target gene nomination. While the field has a long way to go to validate the thousands of GWAS associations, we show that progress is being made and provide exemplars of validation studies covering a wide variety of mechanisms, target genes, and disease areas. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-022-01216-w.
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Affiliation(s)
- Ammar J Alsheikh
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA.
| | - Sabrina Wollenhaupt
- Information Research, AbbVie Deutschland GmbH & Co. KG, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Emily A King
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
| | - Jonas Reeb
- Information Research, AbbVie Deutschland GmbH & Co. KG, 67061, Knollstrasse, Ludwigshafen, Germany
| | - Sujana Ghosh
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
| | | | - Saleh Tamim
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
| | - Jozef Lazar
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
| | - J Wade Davis
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
| | - Howard J Jacob
- Genomics Research Center, AbbVie Inc, North Chicago, Illinois, 60064, USA
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4
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Zhou Z, Zhang C, Ma Z, Wang H, Tuo B, Cheng X, Liu X, Li T. Pathophysiological role of ion channels and transporters in HER2-positive breast cancer. Cancer Gene Ther 2022; 29:1097-1104. [PMID: 34997219 DOI: 10.1038/s41417-021-00407-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/21/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022]
Abstract
The incidence of breast cancer (BC) has been increasing each year, and BC is now the most common malignant tumor in women. Among the numerous BC subtypes, HER2-positive BC can be treated with a variety of strategies based on targeting HER2. Although there has been great progress in the treatment of HER2-positive BC, recurrence, metastasis and drug resistance remain considerable challenges. The dysfunction of ion channels and transporters can affect the development and progression of HER2-positive BC, so these entities are expected to be new therapeutic targets. This review summarizes various ion channels and transporters associated with HER2-positive BC and suggests potential targets for the development of new and effective therapies.
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Affiliation(s)
- Zhengxing Zhou
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Chengmin Zhang
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Zhiyuan Ma
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Hu Wang
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Xiaoming Cheng
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China
| | - Xuemei Liu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China.
| | - Taolang Li
- Department of Thyroid and Breast Surgery, Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, Guizhou Province, China.
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5
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Sodium bicarbonate transporter NBCe1 regulates proliferation and viability of human prostate cancer cells LNCaP and PC3. Oncol Rep 2021; 46:129. [PMID: 34013380 PMCID: PMC8144930 DOI: 10.3892/or.2021.8080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/29/2021] [Indexed: 12/16/2022] Open
Abstract
Studies on cultured cancer cells or cell lines have revealed multiple acid extrusion mechanisms and their involvement in cancer cell growth and progression. In the present study, the role of the sodium bicarbonate transporters (NBCs) in prostate cancer cell proliferation and viability was examined. qPCR revealed heterogeneous expression of five NBC isoforms in human prostate cancer cell lines LNCaP, PC3, 22RV1, C4-2, DU145, and the prostate cell line RWPE-1. In fluorescence pH measurement of LNCaP cells, which predominantly express NBCe1, Na+ and HCO3–-mediated acid extrusion was identified by bath ion replacement and sensitivity to the NBC inhibitor S0859. NBCe1 knockdown using siRNA oligonucleotides decreased the number of viable cells, and pharmacological inhibition with S0859 (50 µM) resulted in a similar decrease. NBCe1 knockdown and inhibition also increased cell death, but this effect was small and slow. In PC3 cells, which express all NBC isoforms, NBCe1 knockdown decreased viable cell number and increased cell death. The effects of NBCe1 knockdown were comparable to those by S0859, indicating that NBCe1 among NBCs primarily contributes to PC3 cell proliferation and viability. S0859 inhibition also decreased the formation of cell spheres in 3D cultures. Immunohistochemistry of human prostate cancer tissue microarrays revealed NBCe1 localization to the glandular epithelial cells in prostate tissue and robust expression in acinar and duct adenocarcinoma. In conclusion, our study demonstrates that NBCe1 regulates acid extrusion in prostate cancer cells and inhibiting or abolishing this transporter decreases cancer cell proliferation.
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6
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Abstract
Acidic metabolic waste products accumulate in the tumor microenvironment because of high metabolic activity and insufficient perfusion. In tumors, the acidity of the interstitial space and the relatively well-maintained intracellular pH influence cancer and stromal cell function, their mutual interplay, and their interactions with the extracellular matrix. Tumor pH is spatially and temporally heterogeneous, and the fitness advantage of cancer cells adapted to extracellular acidity is likely particularly evident when they encounter less acidic tumor regions, for instance, during invasion. Through complex effects on genetic stability, epigenetics, cellular metabolism, proliferation, and survival, the compartmentalized pH microenvironment favors cancer development. Cellular selection exacerbates the malignant phenotype, which is further enhanced by acid-induced cell motility, extracellular matrix degradation, attenuated immune responses, and modified cellular and intercellular signaling. In this review, we discuss how the acidity of the tumor microenvironment influences each stage in cancer development, from dysplasia to full-blown metastatic disease.
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Affiliation(s)
- Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Stine F. Pedersen
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
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7
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Elingaard-Larsen LO, Rolver MG, Sørensen EE, Pedersen SF. How Reciprocal Interactions Between the Tumor Microenvironment and Ion Transport Proteins Drive Cancer Progression. Rev Physiol Biochem Pharmacol 2020; 182:1-38. [PMID: 32737753 DOI: 10.1007/112_2020_23] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Solid tumors comprise two major components: the cancer cells and the tumor stroma. The stroma is a mixture of cellular and acellular components including fibroblasts, mesenchymal and cancer stem cells, endothelial cells, immune cells, extracellular matrix, and tumor interstitial fluid. The insufficient tumor perfusion and the highly proliferative state and dysregulated metabolism of the cancer cells collectively create a physicochemical microenvironment characterized by altered nutrient concentrations and varying degrees of hypoxia and acidosis. Furthermore, both cancer and stromal cells secrete numerous growth factors, cytokines, and extracellular matrix proteins which further shape the tumor microenvironment (TME), favoring cancer progression.Transport proteins expressed by cancer and stromal cells localize at the interface between the cells and the TME and are in a reciprocal relationship with it, as both sensors and modulators of TME properties. It has been amply demonstrated how acid-base and nutrient transporters of cancer cells enable their growth, presumably by contributing both to the extracellular acidosis and the exchange of metabolic substrates and waste products between cells and TME. However, the TME also impacts other transport proteins important for cancer progression, such as multidrug resistance proteins. In this review, we summarize current knowledge of the cellular and acellular components of solid tumors and their interrelationship with key ion transport proteins. We focus in particular on acid-base transport proteins with known or proposed roles in cancer development, and we discuss their relevance for novel therapeutic strategies.
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Affiliation(s)
- Line O Elingaard-Larsen
- Translational Type 2 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, Gentofte, Denmark
| | - Michala G Rolver
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Ester E Sørensen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Stine F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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8
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Rath M, Li Q, Li H, Lindström S, Miron A, Miron P, Dowton AE, Meyer ME, Larson BG, Pomerantz M, Seo JH, Collins LC, Vardeh H, Brachtel E, Come SE, Borges V, Schapira L, Tamimi RM, Partridge AH, Freedman M, Ruddy KJ. Evaluation of significant genome-wide association studies risk - SNPs in young breast cancer patients. PLoS One 2019; 14:e0216997. [PMID: 31125336 PMCID: PMC6534300 DOI: 10.1371/journal.pone.0216997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 05/02/2019] [Indexed: 02/06/2023] Open
Abstract
Purpose Genome-wide-association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) that are associated with an increased risk of breast cancer. Most of these studies were conducted primarily in postmenopausal breast cancer patients. Therefore, we set out to assess whether or not these breast cancer variants are also associated with an elevated risk of breast cancer in young premenopausal patients. Methods In 451 women of European ancestry who had prospectively enrolled in a longitudinal cohort study for women diagnosed with breast cancer at or under age 40, we genotyped 44 SNPs that were previously associated with breast cancer risk. A control group was comprised of 1142 postmenopausal healthy women from the Nurses’ Health Study (NHS). We assessed if the frequencies of the adequately genotyped SNPs differed significantly (p≤0.05) between the cohort of young breast cancer patients and postmenopausal controls, and then we corrected for multiple testing. Results Genotyping of the controls or cases was inadequate for comparisons between the groups for seven of the 44 SNPs. 9 of the remaining 37 were associated with breast cancer risk in young women with a p-value <0.05: rs10510102, rs1219648, rs13387042, rs1876206, rs2936870, rs2981579, rs3734805, rs3803662 and rs4973768. The directions of these associations were consistent with those in postmenopausal women. However, after correction for multiple testing (Benjamini Hochberg) none of the results remained statistically significant. Conclusion After correction for multiple testing, none of the alleles for postmenopausal breast cancer were clearly associated with risk of premenopausal breast cancer in this relatively small study.
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Affiliation(s)
- Michelle Rath
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Qiyuan Li
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
- National Engineering Research Center for Biochip, Shanghai Biochip Limited Corporation, Shanghai, China
| | - Huili Li
- National Engineering Research Center for Biochip, Shanghai Biochip Limited Corporation, Shanghai, China
| | - Sara Lindström
- Department of Epidemiology, University of Washington, Seattle, United States of America
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States of America
| | - Alexander Miron
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, United States of America
| | - Penelope Miron
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, United States of America
| | - Anne E. Dowton
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Meghan E. Meyer
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Bryce G. Larson
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Mark Pomerantz
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Ji-Heui Seo
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Laura C. Collins
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States of America
| | - Hilde Vardeh
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States of America
| | - Elena Brachtel
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, United States of America
| | - Steven E. Come
- Beth Israel Deaconess Medical Center, Boston, United States of America
| | - Virginia Borges
- University of Colorado Denver, Aurora, United States of America
| | - Lidia Schapira
- Stanford University Medical Center, Palo Alto, United States of America
| | - Rulla M. Tamimi
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, United States of America
| | - Ann H. Partridge
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Matthew Freedman
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States of America
| | - Kathryn J. Ruddy
- Department of Oncology, Mayo Clinic, Rochester, United States of America
- * E-mail:
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9
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Gorbatenko A, Søkilde R, Sorensen EE, Newie I, Persson H, Morancho B, Arribas J, Litman T, Rovira C, Pedersen SF. HER2 and p95HER2 differentially regulate miRNA expression in MCF-7 breast cancer cells and downregulate MYB proteins through miR-221/222 and miR-503. Sci Rep 2019; 9:3352. [PMID: 30833639 PMCID: PMC6399295 DOI: 10.1038/s41598-019-39733-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/04/2019] [Indexed: 12/18/2022] Open
Abstract
The HER2 oncogene and its truncated form p95HER2 play central roles in breast cancer. Here, we show that although HER2 and p95HER2 generally elicit qualitatively similar changes in miRNA profile in MCF-7 breast cancer cells, a subset of changes are distinct and p95HER2 shifts the miRNA profile towards the basal breast cancer subtype. High-throughput miRNA profiling was carried out 15, 36 and 60 h after HER2 or p95HER2 expression and central hits validated by RT-qPCR. miRNAs strongly regulated by p95HER2 yet not by HER2, included miR-221, miR-222, miR-503, miR-29a, miR-149, miR-196 and miR-361. Estrogen receptor-α (ESR1) expression was essentially ablated by p95HER2 expression, in a manner recapitulated by miR-221/-222 mimics. c-Myb family transcription factors MYB and MYBL1, but not MYBL2, were downregulated by p95HER2 and by miR-503 or miR-221/-222 mimics. MYBL1 3′UTR inhibition by miR-221/222 was lost by deletion of a single putative miR-221/222 binding sites. p95HER2 expression, or knockdown of either MYB protein, elicited upregulation of tissue inhibitor of matrix metalloprotease-2 (TIMP2). miR-221/222 and -503 mimics increased, and TIMP2 knockdown decreased, cell migration and invasion. A similar pathway was operational in T47D- and SKBr-3 cells. This work reveals important differences between HER2- and p95HER2- mediated miRNA changes in breast cancer cells, provides novel mechanistic insight into regulation of MYB family transcription factors by p95HER2, and points to a role for a miR-221/222– MYB family–TIMP2 axis in regulation of motility in breast cancer cells.
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Affiliation(s)
- Andrej Gorbatenko
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, 10029, USA.,Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark
| | - Rolf Søkilde
- BioCare, Strategic Cancer Research Program, Lund, Sweden.,Department of Clinical Sciences Lund, Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Ester E Sorensen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark
| | - Inga Newie
- BioCare, Strategic Cancer Research Program, Lund, Sweden.,Department of Clinical Sciences Lund, Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Helena Persson
- BioCare, Strategic Cancer Research Program, Lund, Sweden.,Department of Clinical Sciences Lund, Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Beatriz Morancho
- Preclinical Research Program, Vall d'Hebron Institute of Oncology and CIBERONC, 08035, Barcelona, Spain
| | - Joaquin Arribas
- Preclinical Research Program, Vall d'Hebron Institute of Oncology and CIBERONC, 08035, Barcelona, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autonoma de Barcelona, Campus de la UAB, JA, Bellaterra, Spain.,Institució Catalana de Recerca i Estudis Avançats, JA, Barcelona, Spain
| | - Thomas Litman
- Department of International Health, Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Carlos Rovira
- BioCare, Strategic Cancer Research Program, Lund, Sweden.,Department of Clinical Sciences Lund, Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
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10
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Flinck M, Kramer SH, Schnipper J, Andersen AP, Pedersen SF. The acid-base transport proteins NHE1 and NBCn1 regulate cell cycle progression in human breast cancer cells. Cell Cycle 2018; 17:1056-1067. [PMID: 29895196 DOI: 10.1080/15384101.2018.1464850] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Precise acid-base homeostasis is essential for maintaining normal cell proliferation and growth. Conversely, dysregulated acid-base homeostasis, with increased acid extrusion and marked extracellular acidification, is an enabling feature of solid tumors, yet the mechanisms through which intra- and extracellular pH (pHi, pHe) impact proliferation and growth are incompletely understood. The aim of this study was to determine the impact of pH, and specifically of the Na+/H+ exchanger NHE1 and Na+, HCO3- transporter NBCn1, on cell cycle progression and its regulators in human breast cancer cells. Reduction of pHe to 6.5, a common condition in tumors, significantly delayed cell cycle progression in MCF-7 human breast cancer cells. The NHE1 protein level peaked in S phase and that of NBCn1 in G2/M. Steady state pHi changed through the cell cycle, from 7.1 in early S phase to 6.8 in G2, recovering again in M phase. This pattern, as well as net acid extrusion capacity, was dependent on NHE1 and NBCn1. Accordingly, knockdown of either NHE1 or NBCn1 reduced proliferation, prolonged cell cycle progression in a manner involving S phase prolongation and delayed G2/M transition, and altered the expression pattern and phosphorylation of cell cycle regulatory proteins. Our work demonstrates, for the first time, that both NHE1 and NBCn1 regulate cell cycle progression in breast cancer cells, and we propose that this involves cell cycle phase-specific pHi regulation by the two transporters.
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Affiliation(s)
- Mette Flinck
- a Section for Cell Biology and Physiology, Department of Biology , University of Copenhagen , Copenhagen Ø , Denmark
| | - Signe Hoejland Kramer
- a Section for Cell Biology and Physiology, Department of Biology , University of Copenhagen , Copenhagen Ø , Denmark
| | - Julie Schnipper
- a Section for Cell Biology and Physiology, Department of Biology , University of Copenhagen , Copenhagen Ø , Denmark
| | - Anne Poder Andersen
- a Section for Cell Biology and Physiology, Department of Biology , University of Copenhagen , Copenhagen Ø , Denmark
| | - Stine Falsig Pedersen
- a Section for Cell Biology and Physiology, Department of Biology , University of Copenhagen , Copenhagen Ø , Denmark
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11
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Na+,HCO3–-cotransporter NBCn1 (Slc4a7) accelerates ErbB2-induced breast cancer development and tumor growth in mice. Oncogene 2018; 37:5569-5584. [DOI: 10.1038/s41388-018-0353-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/07/2018] [Accepted: 05/13/2018] [Indexed: 12/20/2022]
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12
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Olesen CW, Vogensen J, Axholm I, Severin M, Schnipper J, Pedersen IS, von Stemann JH, Schrøder JM, Christensen DP, Pedersen SF. Trafficking, localization and degradation of the Na +,HCO 3- co-transporter NBCn1 in kidney and breast epithelial cells. Sci Rep 2018; 8:7435. [PMID: 29743600 PMCID: PMC5943355 DOI: 10.1038/s41598-018-25059-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/13/2018] [Indexed: 01/28/2023] Open
Abstract
The Na+;HCO3− co-transporter NBCn1 (SLC4A7) is a major regulator of intracellular pH yet its trafficking and turnover are essentially unstudied. Here, we used MDCK-II and MCF-7 cells to investigate these processes in epithelial cells. GFP-NBCn1 membrane localization was abolished by truncation of the full NBCn1 C-terminal tail (C-tail) yet did not require the C-terminal PDZ-binding motif (ETSL). Glutathione-S-Transferase-pulldown of the C-tail followed by mass spectrometry analysis revealed putative interactions with multiple sorting-, degradation- and retention factors, including the scaffolding protein RACK1. Pulldown of FLAG-tagged deletion constructs mapped the RACK1 interaction to the proximal NBCn1 C-tail. Proximity Ligation Assay and co-immunoprecipitation confirmed that native NBCn1 interacts with RACK1 in a cellular context. Consistent with a functional role of this complex, RACK1 knockdown reduced NBCn1 membrane localization without affecting total NBCn1 expression. Notably, only non-confluent cells exhibited detectable NBCn1-RACK1 plasma membrane co-localization, suggesting that RACK1 regulates the trafficking of NBCn1 to the membrane. Whereas total NBCn1 degradation was slow, with a half-life of more than 24 h, one-third of surface NBCn1 was constitutively endocytosed from the basolateral membrane within 60 min. This suggests that a fraction of NBCn1 exhibits recycling between the basolateral membrane and intracellular compartment(s). Our findings have important implications for understanding NBCn1 regulation as well as its dysregulation in disease.
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Affiliation(s)
- Christina Wilkens Olesen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jens Vogensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Ida Axholm
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Julie Schnipper
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Isabella Skandorff Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jakob Hjorth von Stemann
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Jacob Morville Schrøder
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Dan Ploug Christensen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.
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13
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Andersen AP, Samsøe-Petersen J, Oernbo EK, Boedtkjer E, Moreira JMA, Kveiborg M, Pedersen SF. The net acid extruders NHE1, NBCn1 and MCT4 promote mammary tumor growth through distinct but overlapping mechanisms. Int J Cancer 2018; 142:2529-2542. [PMID: 29363134 DOI: 10.1002/ijc.31276] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/16/2017] [Accepted: 01/17/2018] [Indexed: 01/01/2023]
Abstract
High metabolic and proliferative rates in cancer cells lead to production of large amounts of H+ and CO2 , and as a result, net acid extruding transporters are essential for the function and survival of cancer cells. We assessed protein expression of the Na+ /H+ exchanger NHE1, the Na+ - HCO3- cotransporter NBCn1, and the lactate-H+ cotransporters MCT1 and -4 by immunohistochemical analysis of a large cohort of breast cancer samples. We found robust expression of these transporters in 20, 10, 4 and 11% of samples, respectively. NHE1 and NBCn1 expression both correlated positively with progesterone receptor status, NHE1 correlated negatively and NBCn1 positively with HER2 status, whereas MCT4 expression correlated with lymph node status. Stable shRNA-mediated knockdown (KD) of either NHE1 or NBCn1 in the MDA-MB-231 triple-negative breast cancer (TNBC) cell line significantly reduced steady-state intracellular pH (pHi ) and capacity for pHi recovery after an acid load. Importantly, KD of any of the three transporters reduced in vivo primary tumor growth of MDA-MB-231 xenografts. However, whereas KD of NBCn1 or MCT4 increased tumor-free survival and decreased in vitro proliferation rate and colony growth in soft agar, KD of NHE1 did not have these effects. Moreover, only MCT4 KD reduced Akt kinase activity, PARP and CD147 expression and cell motility. This work reveals that different types of net acid extruding transporters, NHE1, NBCn1 and MCT4, are frequently expressed in patient mammary tumor tissue and demonstrates for the first time that they promote growth of TNBC human mammary tumors in vivo via distinct but overlapping mechanisms.
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Affiliation(s)
- Anne Poder Andersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Samsøe-Petersen
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Eva Kjer Oernbo
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - José M A Moreira
- Section for Molecular Disease Biology, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Kveiborg
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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14
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Parker MD. Mouse models of SLC4-linked disorders of HCO 3--transporter dysfunction. Am J Physiol Cell Physiol 2018; 314:C569-C588. [PMID: 29384695 DOI: 10.1152/ajpcell.00301.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The SLC4 family Cl-/[Formula: see text] cotransporters (NBCe1, NBCe2, NBCn1, and NBCn2) contribute to a variety of vital physiological processes including pH regulation and epithelial fluid secretion. Accordingly, their dysfunction can have devastating effects. Disorders such as epilepsy, hemolytic anemia, glaucoma, hearing loss, osteopetrosis, and renal tubular acidosis are all genetically linked to SLC4-family gene loci. This review summarizes how studies of Slc4-modified mice have enhanced our understanding of the etiology of SLC4-linked pathologies and the interpretation of genetic linkage studies. The review also surveys the novel disease signs exhibited by Slc4-modified mice which could either be considered to presage their description in humans, or to highlight interspecific differences. Finally, novel Slc4-modified mouse models are proposed, the study of which may further our understanding of the basis and treatment of SLC4-linked disorders of [Formula: see text]-transporter dysfunction.
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Affiliation(s)
- Mark D Parker
- Department of Physiology and Biophysics, The State University of New York: The University at Buffalo , Buffalo, New York.,Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo: The State University of New York , Buffalo, New York.,State University of New York Eye Institutes, University at Buffalo: The State University of New York , Buffalo, New York
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15
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Park HJ, Lee S, Ju E, Jones JA, Choi I. Alternative transcription of sodium/bicarbonate transporter SLC4A7 gene enhanced by single nucleotide polymorphisms. Physiol Genomics 2017; 49:167-176. [PMID: 28087757 PMCID: PMC5374452 DOI: 10.1152/physiolgenomics.00112.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 12/31/2022] Open
Abstract
Genome-wide association studies have identified the single nucleotide polymorphism (SNP) rs3278 in the human SLC4A7 gene as one of the marker loci for addiction vulnerability. This marker is located in an intron of the gene, and its genomic role has been unknown. In this study, we examined rs3278 and three adjacent SNPs prevalent in alcoholics for their effects on an alternative promoter that would lead to the production of the NH2-terminally truncated protein NBCn1ΔN450, missing the first 450 amino acids. Analysis of the transcription start site database and a promoter prediction algorithm identified a cluster of three promoters in intron 7 and two short CpG-rich sites in intron 6. The promoter closest to rs3278 showed strong transcription activity in luciferase reporter gene assays. Major-to-minor allele substitution at rs3278 resulted in increased transcription activity. Equivalent substitutions at adjacent rs3772723 (intron 7) and rs13077400 (exon 8) had negligible effect; however, the substitution at nonsynonymous rs3755652 (exon 8) increased the activity by more than twofold. The concomitant substitution at rs3278/rs3755652 produced an additive effect. The rs3755652 had more profound effects on the promoter than the upstream regulatory CpG sites. The amino acid change E326K caused by rs3755652 had negligible effect on transporter function. In HEK 293 cells, NBCn1ΔN450 was expressed in plasma membranes, but at significantly lower levels than the nontruncated NBCn1-E. The pH change mediated by NBCn1ΔN450 was also low. We conclude that rs3278 and rs3755652 stimulate an alternative transcription of the SLC4A7 gene, increasing the production of a defective transporter.
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Affiliation(s)
- Hae Jeong Park
- Department of Pharmacology, Kyung Hee University School of Medicine, Seoul, South Korea; and
| | - Soojung Lee
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Eunji Ju
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Jayre A Jones
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Inyeong Choi
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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