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Pendleton E, Ketner A, Ransick P, Ardekani D, Bodenstine T, Chandar N. Loss of Function of the Retinoblastoma Gene Affects Gap Junctional Intercellular Communication and Cell Fate in Osteoblasts. BIOLOGY 2024; 13:39. [PMID: 38248470 PMCID: PMC10813623 DOI: 10.3390/biology13010039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/08/2023] [Accepted: 01/05/2024] [Indexed: 01/23/2024]
Abstract
Loss of function of the Retinoblastoma gene (RB1) due to mutations is commonly seen in human osteosarcomas. One of the Rb1 gene functions is to facilitate cell fate from mesenchymal stem cells to osteoblasts and prevent adipocyte differentiations. In this study, we demonstrate that a stable reduction of Rb1 expression (RbKD) in murine osteoblasts causes them to express higher levels of PPAR-ɣ and other adipocyte-specific transcription factors while retaining high expression of osteoblast-specific transcription factors, Runx2/Cbfa1 and SP7/Osterix. Inhibition of gap junctional intercellular communication (GJIC) in osteoblasts is another mechanism that causes osteoblasts to transdifferentiate to adipocytes. We found that preosteoblasts exposed to osteoblast differentiating media (DP media) increased GJIC. RbKD cells showed reduced GJIC along with a reduction in expression of Cx43, the protein that mediates GJIC. Other membrane associated adhesion protein Cadherin 11 (Cad11) was also decreased. Since PPAR-ɣ is increased with Rb1 loss, we wondered if the reduction of this transcription factor would reverse the changes observed. Reduction of PPAR-ɣ in control osteoblasts slightly increased bone-specific expression and reduced adipocytic expression as expected along with an increase in Cad11 and Cx43 expression. GJIC remained high and was unaffected by a reduction in PPAR-ɣ in control cells. Knockdown of PPAR-ɣ in RbKD cells reduced adipocyte gene expression, while osteoblast-specific expression showed improvement. Cx43, Cad11 and GJIC remained unaffected by PPAR-ɣ reduction. Our observations suggest that increased PPAR-ɣ that happens with Rb1 loss only affects osteoblast-adipocyte-specific gene expression but does not completely reverse Cx43 gene expression or GJIC. Therefore, these effects may represent independent events triggered by Rb1loss and/or the differentiation process.
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Affiliation(s)
- Elisha Pendleton
- Department of Biochemistry and Molecular Genetics, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (E.P.); (A.K.); (T.B.)
| | - Anthony Ketner
- Department of Biochemistry and Molecular Genetics, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (E.P.); (A.K.); (T.B.)
| | - Phil Ransick
- Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA; (P.R.); (D.A.)
| | - Doug Ardekani
- Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA; (P.R.); (D.A.)
| | - Thomas Bodenstine
- Department of Biochemistry and Molecular Genetics, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (E.P.); (A.K.); (T.B.)
| | - Nalini Chandar
- Department of Biochemistry and Molecular Genetics, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA; (E.P.); (A.K.); (T.B.)
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Ramirez Moreno M, Stempor PA, Bulgakova NA. Interactions and Feedbacks in E-Cadherin Transcriptional Regulation. Front Cell Dev Biol 2021; 9:701175. [PMID: 34262912 PMCID: PMC8273600 DOI: 10.3389/fcell.2021.701175] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/04/2021] [Indexed: 01/07/2023] Open
Abstract
Epithelial tissues rely on the adhesion between participating cells to retain their integrity. The transmembrane protein E-cadherin is the major protein that mediates homophilic adhesion between neighbouring cells and is, therefore, one of the critical components for epithelial integrity. E-cadherin downregulation has been described extensively as a prerequisite for epithelial-to-mesenchymal transition and is a hallmark in many types of cancer. Due to this clinical importance, research has been mostly focused on understanding the mechanisms leading to transcriptional repression of this adhesion molecule. However, in recent years it has become apparent that re-expression of E-cadherin is a major step in the progression of many cancers during metastasis. Here, we review the currently known molecular mechanisms of E-cadherin transcriptional activation and inhibition and highlight complex interactions between individual mechanisms. We then propose an additional mechanism, whereby the competition between adhesion complexes and heterochromatin protein-1 for binding to STAT92E fine-tunes the levels of E-cadherin expression in Drosophila but also regulates other genes promoting epithelial robustness. We base our hypothesis on both existing literature and our experimental evidence and suggest that such feedback between the cell surface and the nucleus presents a powerful paradigm for epithelial resilience.
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Affiliation(s)
- Miguel Ramirez Moreno
- Department of Biomedical Science and Bateson Centre, The University of Sheffield, Sheffield, England
| | | | - Natalia A Bulgakova
- Department of Biomedical Science and Bateson Centre, The University of Sheffield, Sheffield, England
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Pendleton E, Chandar N. In Vitro Differentiation of Preosteoblast-Like Cells, MC3T3-E1, to Adipocytes Is Enhanced by 1,25(OH) 2 Vitamin D 3. Front Endocrinol (Lausanne) 2017; 8:128. [PMID: 28670298 PMCID: PMC5472651 DOI: 10.3389/fendo.2017.00128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 05/26/2017] [Indexed: 12/25/2022] Open
Abstract
Osteoblasts and adipocytes originate from common mesenchymal progenitor cells and are controlled by specific transcription factors. While 1,25-dihydroxyvitamin D3 (vitamin D) is known to be an important factor for osteoblast differentiation, there are conflicting reports regarding its effect on adipogenesis. In this study, we attempted to understand the effect of exposure of preosteoblasts (MC3T3-E1) to adipogenic media with and without vitamin D and determined the expression of adipogenic genes during this process. Our studies show that while transdifferentiation of preosteoblasts occurred on exposure to adipogenic media, the effect of vitamin D treatment was synergistic resulting in several hundred fold increase in adipocyte transcription factors C/EBPα and peroxisome proliferator-activated receptor-gamma (P < 0.001) along with an increase in markers of adipogenesis and accumulation of lipid droplets in cells. Vitamin D treatment was also accompanied by 100-fold to 700-fold increases in vitamin D receptor expression during the treatment period (P < 0.001). To determine how the effect of vitamin D might compare to other genetic manipulations that promote adipogenic differentiation, we stably knocked down retinoblastoma expression in MC3T3-E1 cells. Recent studies have suggested retinoblastoma (Rb1) tumor suppressor gene function to be critical to maintain osteoblasts function and inhibit adipocyte differentiation. We exposed MC3T3-E1 cells with reduced Rb1 expression to adipogenic media and found an increase in adipogenic differentiation when compared to cells with a full complement of Rb dosage. However, the extent of the change was not as dramatic as seen with vitamin D. These studies show that preosteoblasts are sensitive and respond to these manipulations that favor the adipocytic phenotype. While vitamin D is not known to directly affect targets in adipogenesis, our observations may have resulted from the malleability of preosteoblast genome in MC3T3-E1 cells, which allowed adipocyte specific gene expression under appropriate stimuli. Why this pathway is influenced and subverted by an anabolic bone factor such as vitamin D remains to be determined.
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Affiliation(s)
- Elisha Pendleton
- Department of Biochemistry, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, United States
| | - Nalini Chandar
- Department of Biochemistry, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, United States
- *Correspondence: Nalini Chandar,
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Commentary on Alfred G. Knudson, Jr.: “Hereditary Cancer, Oncogenes, and Antioncogenes”. Cancer Res 2016; 76:2851-3. [DOI: 10.1158/0008-5472.can-16-1142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 04/20/2016] [Indexed: 11/16/2022]
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Osteosarcoma: prognosis plateau warrants retinoblastoma pathway targeted therapy. Signal Transduct Target Ther 2016; 1:16001. [PMID: 29263893 PMCID: PMC5657420 DOI: 10.1038/sigtrans.2016.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/31/2015] [Accepted: 01/04/2016] [Indexed: 02/06/2023] Open
Abstract
Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents, affecting ~560 young patients in the United States annually. The term OS describes a diverse array of subtypes with varying prognoses, but the majority of tumors are high grade and aggressive. Perhaps because the true etiology of these aggressive tumors remains unknown, advances in OS treatment have reached a discouraging plateau, with only incremental improvements over the past 40 years. Thus, research surrounding the pathogenesis of OS is essential, as it promises to unveil novel therapeutic targets that can attack tumor cells with greater specificity and lower toxicity. Among the candidate molecular targets in OS, the retinoblastoma (RB) pathway demonstrates the highest frequency of inactivation and thus represents a particularly promising avenue for molecular targeted therapy. This review examines the present thinking and practices in OS treatment and specifically highlights the relevance of the RB pathway in osteosarcomagenesis. Through further investigation into RB pathway-related novel therapeutic targets, we believe that a near-term breakthrough in improved OS prognosis is possible.
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Marie PJ, Haÿ E, Saidak Z. Integrin and cadherin signaling in bone: role and potential therapeutic targets. Trends Endocrinol Metab 2014; 25:567-75. [PMID: 25034128 DOI: 10.1016/j.tem.2014.06.009] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 12/16/2022]
Abstract
Cell-cell and cell-matrix interactions mediated by cell adhesion molecules are important mechanisms controlling cell fate and function. Here, we review recent advances in the implication of the cell adhesion molecules integrins and cadherins in the control of osteoblastogenesis and bone formation. We discuss emerging evidence indicating that signaling pathways mediated by integrins and cadherins and their crosstalk with the Wnt/β-catenin signaling pathway regulate osteogenic differentiation and mechanotransduction. We also offer a comprehensive view of the mechanisms by which some integrins and cadherins control the differentiation of cells of the osteoblast lineage in bone marrow niches. Understanding how specific integrins or cadherins may promote osteogenic cell differentiation, bone formation, and repair may lead to novel therapeutic strategies.
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Affiliation(s)
- Pierre J Marie
- UMR-1132 INSERM and University Paris Diderot, Sorbonne Paris Cité, Paris, 75475 cedex 10, France.
| | - Eric Haÿ
- UMR-1132 INSERM and University Paris Diderot, Sorbonne Paris Cité, Paris, 75475 cedex 10, France
| | - Zuzana Saidak
- UMR-1132 INSERM and University Paris Diderot, Sorbonne Paris Cité, Paris, 75475 cedex 10, France
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Haÿ E, Dieudonné FX, Saidak Z, Marty C, Brun J, Da Nascimento S, Sonnet P, Marie PJ. N-cadherin/wnt interaction controls bone marrow mesenchymal cell fate and bone mass during aging. J Cell Physiol 2014; 229:1765-75. [PMID: 24664975 DOI: 10.1002/jcp.24629] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/21/2014] [Indexed: 01/25/2023]
Abstract
Age-related bone loss is characterized by reduced osteoblastogenesis and excessive bone marrow adipogenesis. The mechanisms governing bone marrow mesenchymal stromal cell (BMSC) differentiation into adipocytes or osteoblasts during aging are unknown. We show here that overexpressing N-cadherin (Cadh2) in osteoblasts increased BMSC adipocyte differentiation and reduced osteoblast differentiation in young transgenic (Tg) mice whereas this phenotype was fully reversed with aging. The reversed phenotype with age was associated with enhanced Wnt5a and Wnt10b expression in osteoblasts and a concomitant increase in BMSC osteogenic differentiation. Consistent with this mechanism, conditioned media from young wild type osteoblasts inhibited adipogenesis and promoted osteoblast differentiation in BMSC from old Cadh2 Tg mice, and this response was abolished by Wnt5a and Wnt10b silencing. Transplantation of BMSC from old Cadh2 Tg mice into young Tg recipients increased Wnt5a and Wnt10b expression and rescued BMSC osteogenic differentiation. In senescent osteopenic mice, blocking the CADH2-Wnt interaction using an antagonist peptide increased Wnt5a and Wnt10b expression, bone formation, and bone mass. The data indicate that Cadh2/Wnt interaction in osteoblasts regulates BMSC lineage determination, bone formation, and bone mass and suggest a therapeutic target for promoting bone formation in the aging skeleton.
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Affiliation(s)
- Eric Haÿ
- Inserm UMR-1132, Paris, France; University Paris Diderot, Sorbonne Paris Cité, Paris, France
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Marie PJ, Haÿ E, Modrowski D, Revollo L, Mbalaviele G, Civitelli R. Cadherin-mediated cell-cell adhesion and signaling in the skeleton. Calcif Tissue Int 2014; 94:46-54. [PMID: 23657489 PMCID: PMC4272239 DOI: 10.1007/s00223-013-9733-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/08/2013] [Indexed: 01/01/2023]
Abstract
Direct cell-to-cell interactions via cell adhesion molecules, in particular cadherins, are critical for morphogenesis, tissue architecture, and cell sorting and differentiation. Partially overlapping, yet distinct roles of N-cadherin (cadherin-2) and cadherin-11 in the skeletal system have emerged from mouse genetics and in vitro studies. Both cadherins are important for precursor commitment to the osteogenic lineage, and genetic ablation of Cdh2 and Cdh11 results in skeletal growth defects and impaired bone formation. While Cdh11 defines the osteogenic lineage, persistence of Cdh2 in osteoblasts in vivo actually inhibits their terminal differentiation and impairs bone formation. The action of cadherins involves both cell-cell adhesion and interference with intracellular signaling, and in particular the Wnt/β-catenin pathway. Both cadherin-2 and cadherin-11 bind to β-catenin, thus modulating its cytoplasmic pools and transcriptional activity. Recent data demonstrate that cadherin-2 also interferes with Lrp5/6 signaling by sequestering these receptors in inactive pools via axin binding. These data extend the biologic action of cadherins in bone forming cells, and provide novel mechanisms for development of therapeutic strategies aimed at enhancing bone formation.
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Affiliation(s)
- Pierre J Marie
- Laboratory of Osteoblast Biology and Pathology, Inserm UMR-606, Hôpital Lariboisière, 2 rue Ambroise Paré, 75475, Paris Cedex 10, France,
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