Publications by authors named "Gary S Stein"

372 Publications

Hypoxia-inducible factor 2α is a novel inhibitor of chondrocyte maturation.

J Cell Physiol 2021 Mar 21. Epub 2021 Mar 21.

Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, Korea Mouse Phenotyping Center, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.

Hypoxic environment is essential for chondrocyte maturation and longitudinal bone growth. Although hypoxia-inducible factor 1 alpha (Hif-1α) has been known as a key player for chondrocyte survival and function, the function of Hif-2α in cartilage is mechanistically and clinically relevant but remains unknown. Here we demonstrated that Hif-2α was a novel inhibitor of chondrocyte maturation through downregulation of Runx2 stability. Mechanistically, Hif-2α binding to Runx2 inhibited chondrocyte maturation by Runx2 degradation through disrupting Runx2/Cbfβ complex formation. The Hif-2α-mediated-Runx2 degradation could be rescued by Cbfβ transfection due to the increase of Runx2/Cbfβ complex formation. Consistently, mesenchymal cells derived from Hif-2α heterozygous mice were more rapidly differentiated into hypertrophic chondrocytes than those of wild-type mice in a micromass culture system. Collectively, these findings demonstrate that Hif-2α is a novel inhibitor for chondrocyte maturation by disrupting Runx2/Cbfβ complex formation and consequential regulatory activity.
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http://dx.doi.org/10.1002/jcp.30356DOI Listing
March 2021

Mesenchymal stem cells overexpressing BMP-9 by CRISPR-Cas9 present high in vitro osteogenic potential and enhance in vivo bone formation.

Gene Ther 2021 Mar 8. Epub 2021 Mar 8.

Bone Research Lab, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

Cell therapy is a valuable strategy for the replacement of bone grafts and repair bone defects, and mesenchymal stem cells (MSCs) are the most frequently used cells. This study was designed to genetically edit MSCs to overexpress bone morphogenetic protein 9 (BMP-9) using Clustered Regularly Interspaced Short Palindromic Repeats/associated nuclease Cas9 (CRISPR-Cas9) technique to generate iMSCs-VPR, followed by in vitro evaluation of osteogenic potential and in vivo enhancement of bone formation in rat calvaria defects. Overexpression of BMP-9 was confirmed by its gene expression and protein expression, as well as its targets Hey-1, Bmpr1a, and Bmpr1b, Dlx-5, and Runx2 and  protein expression of SMAD1/5/8 and pSMAD1/5/8. iMSCs-VPR displayed significant changes in the expression of a panel of genes involved in TGF-β/BMP signaling pathway. As expected, overexpression of BMP-9 increased the osteogenic potential of MSCs indicated by increased gene expression of osteoblastic markers Runx2, Sp7, Alp, and Oc, higher ALP activity, and matrix mineralization. Rat calvarial bone defects treated with injection of iMSCs-VPR exhibited increased bone formation and bone mineral density when compared with iMSCs-VPR- and phosphate buffered saline (PBS)-injected defects. This is the first study to confirm that CRISPR-edited MSCs overexpressing BMP-9 effectively enhance bone formation, providing novel options for exploring the capability of genetically edited cells to repair bone defects.
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http://dx.doi.org/10.1038/s41434-021-00248-8DOI Listing
March 2021

A Peer-Based Strategy to Overcome HPV Vaccination Inequities in Rural Communities: A Physical Distancing-Compliant Approach.

Crit Rev Eukaryot Gene Expr 2021 ;31(1):61-69

KM Consulting, New Jersey, USA.

The human papilloma virus (HPV) vaccine is the world's first proven and effective vaccine to prevent cancers in males and females when administered pre-exposure. Like most of the US, barely half of Vermont teens are up-to-date with the vaccination, with comparable deficits in New Hampshire and Maine. The rates for HPV vaccine initiation and completion are as low as 33% in rural New England. Consequently, there is a compelling responsibility to communicate its importance to unvaccinated teenagers before their risk for infection increases. Messaging in rural areas promoting HPV vaccination is compromised by community-based characteristics that include access to appropriate medical care, poor media coverage, parental and peer influence, and skepticism of science and medicine. Current strategies are predominantly passive access to literature and Internet-based information. Evidence indicates that performance-based messaging can clarify the importance of HPV vaccination to teenagers and their parents in rural areas. Increased HPV vaccination will significantly contribute to the prevention of a broadening spectrum of cancers. Reducing rurality-based inequities is a public health priority. Development of a performance-based peer-communication intervention can capture a window of opportunity to provide increasingly effective and sustained HPV protection. An effective approach can be partnering rural schools and regional health teams with a program that is nimble and scalable to respond to public health policies and practices compliant with COVID-19 pandemic-related modifications on physical distancing and interacting in the foreseeable future.
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http://dx.doi.org/10.1615/CritRevEukaryotGeneExpr.2021036945DOI Listing
March 2021

Bioactivity-Guided Isolation and Identification of Anti-adipogenic Constituents from the n-Butanol Fraction of Cissus quadrangularis.

Crit Rev Eukaryot Gene Expr 2020 ;30(6):519-541

School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore, Pakistan.

Obesity is marked by the buildup of fat in adipose tissue that increases body weight and the risk of many associated health problems, including diabetes and cardiovascular disease. Treatment options for obesity are limited, and available medications have many side effects. Thus there is a great need to find alternative medicines for treating obesity. This study explores the anti-adipogenic potential of the n-butanol fraction of Cissus quadrangularis (CQ-B) on 3T3-L1 mouse preadipocyte cell line. The expression of various lipogenic marker genes such as adiponectin, peroxisome proliferator-activated receptor gamma, leptin, fatty acid-binding proteins, sterol regulatory element-binding proteins, fetal alcohol syndrome, steroyl-CoA desaturase-1, lipoproteins, acetyl-CoA carboxylase alpha, and acetyl-CoA carboxylase beta were variously significantly downregulated. After establishing the anti-adipogenic potential of CQ-B, it was fractionated to isolate anti-adipogenic compounds. We observed significant reduction in neutral lipid content of differentiated cells treated with various fractions of CQ-B. Gas chromatography-mass spectrometry analysis revealed the presence of thirteen compounds with reported anti-adipogenic activities. Further studies to purify these compounds can offer efficacious and viable treatment options for obesity and related complications.
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http://dx.doi.org/10.1615/CritRevEukaryotGeneExpr.2020036843DOI Listing
January 2020

Inhibition of the RUNX1-CBFβ transcription factor complex compromises mammary epithelial cell identity: a phenotype potentially stabilized by mitotic gene bookmarking.

Oncotarget 2020 Jun 30;11(26):2512-2530. Epub 2020 Jun 30.

Department of Biochemistry and University of Vermont Cancer Center, Robert Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA.

RUNX1 has recently been shown to play an important role in determination of mammary epithelial cell identity. However, mechanisms by which loss of the RUNX1 transcription factor in mammary epithelial cells leads to epithelial-to-mesenchymal transition (EMT) are not known. Here, we report that interaction between RUNX1 and its heterodimeric partner CBFβ is essential for sustaining mammary epithelial cell identity. Disruption of RUNX1-CBFβ interaction, DNA binding, and association with mitotic chromosomes alters cell morphology, global protein synthesis, and phenotype-related gene expression. During interphase, RUNX1 is organized as punctate, predominantly nuclear, foci that are dynamically redistributed during mitosis, with a subset localized to mitotic chromosomes. Genome-wide RUNX1 occupancy profiles for asynchronous, mitotically enriched, and early G1 breast epithelial cells reveal RUNX1 associates with RNA Pol II-transcribed protein coding and long non-coding RNA genes and RNA Pol I-transcribed ribosomal genes critical for mammary epithelial proliferation, growth, and phenotype maintenance. A subset of these genes remains occupied by the protein during the mitosis to G1 transition. Together, these findings establish that the RUNX1-CBFβ complex is required for maintenance of the normal mammary epithelial phenotype and its disruption leads to EMT. Importantly, our results suggest, for the first time, that RUNX1 mitotic bookmarking of a subset of epithelial-related genes may be an important epigenetic mechanism that contributes to stabilization of the mammary epithelial cell identity.
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http://dx.doi.org/10.18632/oncotarget.27637DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7335667PMC
June 2020

Mechanical strain-mediated reduction in RANKL expression is associated with RUNX2 and BRD2.

Gene X 2020 Dec 16;5:100027. Epub 2020 Jan 16.

Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.

Mechanical loading-related strains trigger bone formation by osteoblasts while suppressing resorption by osteoclasts, uncoupling the processes of formation and resorption. Osteocytes may orchestrate this process in part by secreting sclerostin (SOST), which inhibits osteoblasts, and expressing receptor activator of nuclear factor-κB ligand (RANKL/TNFSF11) which recruits osteoclasts. Both SOST and RANKL are targets of the master osteoblastic transcription factor RUNX2. Subjecting human osteoblastic Saos-2 cells to strain by four point bending down-regulates their expression of SOST and RANKL without altering RUNX2 expression. RUNX2 knockdown increases basal SOST expression, but does not alter SOST down-regulation following strain. Conversely, RUNX2 knockdown does not alter basal RANKL expression, but prevents its down-regulation by strain. Chromatin immunoprecipitation revealed RUNX2 occupies a region of the RANKL promoter containing a consensus RUNX2 binding site and its occupancy of this site decreases following strain. The expression of epigenetic acetyl and methyl writers and readers was quantified by RT-qPCR to investigate potential epigenetic bases for this change. Strain and RUNX2 knockdown both down-regulate expression of the bromodomain acetyl reader BRD2. BRD2 and RUNX2 co-immunoprecipitate, suggesting interaction within regulatory complexes, and BRD2 was confirmed to interact with the RUNX2 promoter. BRD2 also occupies the RANKL promoter and its occupancy was reduced following exposure to strain. Thus, RUNX2 may contribute to bone remodeling by suppressing basal SOST expression, while facilitating the acute strain-induced down-regulation of RANKL through a mechanosensitive epigenetic loop involving BRD2.
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http://dx.doi.org/10.1016/j.gene.2020.100027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7285908PMC
December 2020

RUNX1 and RUNX2 transcription factors function in opposing roles to regulate breast cancer stem cells.

J Cell Physiol 2020 10 17;235(10):7261-7272. Epub 2020 Mar 17.

Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, Vermont.

Breast cancer stem cells (BCSCs) are competent to initiate tumor formation and growth and refractory to conventional therapies. Consequently BCSCs are implicated in tumor recurrence. Many signaling cascades associated with BCSCs are critical for epithelial-to-mesenchymal transition (EMT). We developed a model system to mechanistically examine BCSCs in basal-like breast cancer using MCF10AT1 FACS sorted for CD24 (negative/low in BCSCs) and CD44 (positive/high in BCSCs). Ingenuity Pathway Analysis comparing RNA-seq on the CD24 versus CD24 MCF10AT1 indicates that the top activated upstream regulators include TWIST1, TGFβ1, OCT4, and other factors known to be increased in BCSCs and during EMT. The top inhibited upstream regulators include ESR1, TP63, and FAS. Consistent with our results, many genes previously demonstrated to be regulated by RUNX factors are altered in BCSCs. The RUNX2 interaction network is the top significant pathway altered between CD24 and CD24 MCF10AT1. RUNX1 is higher in expression at the RNA level than RUNX2. RUNX3 is not expressed. While, human-specific quantitative polymerase chain reaction primers demonstrate that RUNX1 and CDH1 decrease in human MCF10CA1a cells that have grown tumors within the murine mammary fat pad microenvironment, RUNX2 and VIM increase. Treatment with an inhibitor of RUNX binding to CBFβ for 5 days followed by a 7-day recovery period results in EMT suggesting that loss of RUNX1, rather than increase in RUNX2, is a driver of EMT in early stage breast cancer. Increased understanding of RUNX regulation on BCSCs and EMT will provide novel insight into therapeutic strategies to prevent recurrence.
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http://dx.doi.org/10.1002/jcp.29625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7415511PMC
October 2020

Identification of tRNA-derived small RNA (tsRNA) responsive to the tumor suppressor, RUNX1, in breast cancer.

J Cell Physiol 2020 06 10;235(6):5318-5327. Epub 2020 Jan 10.

Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.

Despite recent advances in targeted therapies, the molecular mechanisms driving breast cancer initiation, progression, and metastasis are minimally understood. Growing evidence indicate that transfer RNA (tRNA)-derived small RNAs (tsRNA) contribute to biological control and aberrations associated with cancer development and progression. The runt-related transcription factor 1 (RUNX1) transcription factor is a tumor suppressor in the mammary epithelium whereas RUNX1 downregulation is functionally associated with breast cancer initiation and progression. We identified four tsRNA (ts-19, ts-29, ts-46, and ts-112) that are selectively responsive to expression of the RUNX1 tumor suppressor. Our finding that ts-112 and RUNX1 anticorrelate in normal-like mammary epithelial and breast cancer lines is consistent with tumor-related activity of ts-112 and tumor suppressor activity of RUNX1. Inhibition of ts-112 in MCF10CA1a aggressive breast cancer cells significantly reduced proliferation. Ectopic expression of a ts-112 mimic in normal-like mammary epithelial MCF10A cells significantly increased proliferation. These findings support an oncogenic potential for ts-112. Moreover, RUNX1 may repress ts-112 to prevent overactive proliferation in breast epithelial cells to augment its established roles in maintaining the mammary epithelium.
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http://dx.doi.org/10.1002/jcp.29419DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238950PMC
June 2020

The epigenetic reader Brd4 is required for osteoblast differentiation.

J Cell Physiol 2020 06 23;235(6):5293-5304. Epub 2019 Dec 23.

Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.

Transcription networks and epigenetic mechanisms including DNA methylation, histone modifications, and noncoding RNAs control lineage commitment of multipotent mesenchymal progenitor cells. Proteins that read, write, and erase histone tail modifications curate and interpret the highly intricate histone code. Epigenetic reader proteins that recognize and bind histone marks provide a crucial link between histone modifications and their downstream biological effects. Here, we investigate the role of bromodomain-containing (BRD) proteins, which recognize acetylated histones, during osteogenic differentiation. Using RNA-sequencing (RNA-seq) analysis, we screened for BRD proteins (n = 40) that are robustly expressed in MC3T3 osteoblasts. We focused functional follow-up studies on Brd2 and Brd4 which are highly expressed in MC3T3 preosteoblasts and represent "bromodomain and extra terminal domain" (BET) proteins that are sensitive to pharmacological agents (BET inhibitors). We show that small interfering RNA depletion of Brd4 has stronger inhibitory effects on osteoblast differentiation than Brd2 loss as measured by osteoblast-related gene expression, extracellular matrix deposition, and alkaline phosphatase activity. Similar effects on osteoblast differentiation are seen with the BET inhibitor +JQ1, and this effect is reversible upon its removal indicating that this small molecule has no lasting effects on the differentiation capacity of MC3T3 cells. Mechanistically, we find that Brd4 binds at known Runx2 binding sites in promoters of bone-related genes. Collectively, these findings suggest that Brd4 is recruited to osteoblast-specific genes and may cooperate with bone-related transcription factors to promote osteoblast lineage commitment and maturation.
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http://dx.doi.org/10.1002/jcp.29415DOI Listing
June 2020

Switches in histone modifications epigenetically control vitamin D3-dependent transcriptional upregulation of the CYP24A1 gene in osteoblastic cells.

J Cell Physiol 2020 06 23;235(6):5328-5339. Epub 2019 Dec 23.

Faculty of Medicine and Faculty of Life Sciences, Institute of Biomedical Sciences and FONDAP Center for Genome Regulation, Universidad Andres Bello-Santiago, Santiago, Chile.

In bone cells vitamin D dependent regulation of gene expression principally occurs through modulation of gene transcription. Binding of the active vitamin D metabolite, 1,25-dihydroxy vitamin D3 (1,25(OH) D ) to the vitamin D receptor (VDR) induces conformational changes in its C-terminal domain enabling competency for interaction with physiologically relevant coactivators, including SRC-1. Consequently, regulatory complexes can be assembled that support intrinsic enzymatic activities with competency to posttranslationally modify chromatin histones at target genomic sequences to epigenetically alter transcription. Here we examine specific transitions in representation and/or enrichment of epigenetic histone marks during 1,25(OH) D mediated upregulation of CYP24A1 gene expression in osteoblastic cells. This gene encodes the 24-hydroxylase enzyme, essential for biological control of vitamin D levels. We demonstrate that as the CYP24A1 gene promoter remains transcriptionally silent, there is enrichment of H4R3me2s together with its "writing" enzyme PRMT5 and decreased abundance of the istone H3 and H4 acetylation, H3R17me2a, and H4R3me2a marks as well as of their corresponding "writers." Exposure of osteoblastic cells to 1,25(OH) D stimulates the recruitment of a VDR/SRC-1 containing complex to the CYP24A1 promoter to mediate increased H3/H4 acetylation. VDR/SRC-1 binding occurs concomitant with the release of PRMT5 and the recruitment of the arginine methyltransferases CARM1 and PRMT1 to catalyze the deposition of the H3R17me2a and H4R3me2a marks, respectively. Our results indicate that these dynamic transitions of histone marks at the CYP24A1 promoter, provide a "chromatin context" that is transcriptionally competent for activation of the CYP24A1 gene in osteoblastic cells in response to 1,25(OH) D .
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http://dx.doi.org/10.1002/jcp.29420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7401294PMC
June 2020

The Thyroid Hormone Receptor-RUNX2 Axis: A Novel Tumor Suppressive Pathway in Breast Cancer.

Horm Cancer 2020 02 21;11(1):34-41. Epub 2019 Dec 21.

Department of Pharmacology, University of Vermont, 89 Beaumont Avenue, Burlington, VT, 05405, USA.

Metastatic breast cancer is refractory to conventional therapies and is an end-stage disease. RUNX2 is a transcription factor that becomes oncogenic when aberrantly expressed in multiple tumor types, including breast cancer, supporting tumor progression and metastases. Our previous work demonstrated that the thyroid hormone receptor beta (TRβ) inhibits RUNX2 expression and tumorigenic characteristics in thyroid cells. As TRβ is a tumor suppressor, we investigated the compelling question whether TRβ also regulates RUNX2 in breast cancer. The Cancer Genome Atlas indicates that TRβ expression is decreased in the most aggressive basal-like subtype of breast cancer. We established that modulated levels of TRβ results in corresponding changes in the high levels of RUNX2 expression in metastatic, basal-like breast cells. The MDA-MB-231 triple-negative breast cancer cell line exhibits low expression of TRβ and high levels of RUNX2. Increased expression of TRβ decreased RUNX2 levels. The thyroid hormone-mediated suppression of RUNX2 is TRβ specific as TRα overexpression failed to alter RUNX2 expression. Consistent with these findings, knockdown of TRβ in non-tumor MCF10A mammary epithelial-like cells results in an increase in RUNX2 and RUNX2 target genes. Mechanistically, TRβ directly interacts with the proximal promoter of RUNX2 through a thyroid hormone response element to reduce promoter activity. The TRβ suppression of the oncogene RUNX2 is a signaling pathway shared by thyroid and breast cancers. Our findings provide a novel mechanism for TRβ-mediated tumor suppression in breast cancers. This pathway may be common to many solid tumors and impact treatment for metastatic cancers.
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http://dx.doi.org/10.1007/s12672-019-00373-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007220PMC
February 2020

Disruption of Broad Epigenetic Domains in PDAC Cells by HAT Inhibitors.

Epigenomes 2019 Jun 2;3(2). Epub 2019 Jun 2.

Biomedical and Health Sciences Department, University of Vermont, Burlington, VT 05405, USA.

The spreading of epigenetic domains has emerged as a distinguishing epigenomic phenotype for diverse cell types. In particular, clusters of H3K27ac- and H3K4me3-marked elements, referred to as super-enhancers, and broad H3K4me3 domains, respectively, have been linked to cell identity and disease states. Here, we characterized the broad domains from different pancreatic ductal adenocarcinoma (PDAC) cell lines that represent distinct histological grades. Our integrative genomic analysis found that human derived cell line models for distinct PDAC grades exhibit characteristic broad epigenetic features associated with gene expression patterns that are predictive of patient prognosis and provide insight into pancreatic cancer cell identity. In particular, we find that genes marked by overlapping Low-Grade broad domains correspond to an epithelial phenotype and hold potential as markers for patient stratification. We further utilize ChIP-seq to compare the effects of histone acetyltransferase (HAT) inhibitors to detect global changes in histone acetylation and methylation levels. We found that HAT inhibitors impact certain broad domains of pancreatic cancer cells. Overall, our results reveal potential roles for broad domains in cells from distinct PDAC grades and demonstrate the plasticity of particular broad epigenomic domains to epigenetic inhibitors.
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http://dx.doi.org/10.3390/epigenomes3020011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897394PMC
June 2019

Osteogenic potential of hexane and dichloromethane fraction of Cissus quadrangularis on murine preosteoblast cell line MC3T3-E1 (subclone 4).

J Cell Physiol 2019 12 26;234(12):23082-23096. Epub 2019 May 26.

School of Biological Sciences, Quaid-i-Azam Campus, University of the Punjab, Lahore, Pakistan.

In continuation of the investigation of osteogenic potential of solvent fractions of ethanolic extract of Cissus quadrangularis (CQ), an ancient medicinal plant, most notably known for its bone-healing properties, to isolate and identify antiosteoporotic compounds. In the current study, we report the effect of hexane fraction (CQ-H) and dichloromethane fraction (CQ-D) of CQ on the differentiation and mineralization of mouse preosteoblast cell line MC3T3-E1 (subclone 4). Growth, viability, and proliferation assays revealed that low concentrations (0.1, 1, and 100 ng/ml) of both solvent fractions were nontoxic, whereas higher concentrations were toxic to the cells. Differentiation and mineralization of MC3T3-E1 with nontoxic concentrations of CQ-D and CQ-H revealed that CQ-D delayed the mineralization of MC3T3-E1 cells. However, early and enhanced mineralization was observed in cultures treated with nontoxic concentrations of CQ-H, as indicated by Von Kossa staining and expression profile of osteoblast marker genes such as osterix, Runx2, alkaline phosphatase (ALP), collagen (Col1a1), integrin-related bone sialoprotein (IBSP), osteopontin (OPN), and osteocalcin (OCN). These findings suggest CQ-H as the most efficacious solvent fraction for further investigation to isolate and identify the active compounds in CQ-H.
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http://dx.doi.org/10.1002/jcp.28869DOI Listing
December 2019

The role of cell adhesion in hematopoiesis and leukemogenesis.

J Cell Physiol 2019 11 13;234(11):19189-19198. Epub 2019 Apr 13.

Department of Biochemistry, University of Vermont, Burlington, Vermont.

The cells of the bone marrow microenvironment are emerging as important contributors and regulators of normal hematopoiesis. This microenvironment is perturbed during leukemogenesis, and evidence points toward a bidirectional communication between leukemia cells and the normal cells of the bone marrow, mediated by direct cell-cell contact as well as soluble factors. These interactions are increasingly appreciated to play a role in leukemogenesis and possibly in resistance to chemotherapy. In fact, several compounds that specifically target the bone marrow microenvironment, including inhibitors of cell adhesion, are being tested as adjuncts to leukemia therapy.
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http://dx.doi.org/10.1002/jcp.28636DOI Listing
November 2019

Inhibition of the chimeric DnaJ-PKAc enzyme by endogenous inhibitor proteins.

J Cell Biochem 2019 08 2;120(8):13783-13791. Epub 2019 Apr 2.

University of Vermont Cancer Center, Burlington, Vermont.

The chimeric DnaJ-PKAc enzymeresulting from an approximately 400-kb deletion of chromosome 19 is a primary contributor to the oncogenic transformation that occurs in fibrolamellar hepatocellular carcinoma, also called fibrolamellar carcinoma (FLC). This oncogenic deletion juxtaposes exon 1 of the DNAJB1 heat shock protein gene with exon 2 of the PRKACA gene encoding the protein kinase A catalytic subunit, resulting in DnaJ-PKAc fusion under the transcriptional control of the DNAJB1 promoter. The expression of DnaJ-PKAc is approximately 10 times that of wild-type (wt) PKAc catalytic subunits, causing elevated and dysregulated kinase activity that contributes to oncogenic transformation. In normal cells, PKAc activity is regulated by a group of endogenous proteins, termed protein kinase inhibitors (PKI) that competitively inhibit PKAc and assist with the nuclear export of the enzyme. Currently, it is scarcely known whether interactions with PKI are perturbed in DnaJ-PKAc. In this report, we survey existing data sets to assess the expression levels of the various PKI isoforms that exist in humans to identify those that are candidates to encounter DnaJ-PKAc in both normal liver and FLC tumors. We then compare inhibition profiles of wtPKAc and DnaJ-PKAc against PKI and demonstrate that extensive structural homology in the active site clefts of the two enzymes confers similar kinase activities and inhibition by full-length PKI and PKI-derived peptides.
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http://dx.doi.org/10.1002/jcb.28651DOI Listing
August 2019

Towards a more precise and individualized assessment of breast cancer risk.

Aging (Albany NY) 2019 02;11(4):1305-1316

University of Vermont Cancer Center, The Robert Larner MD College of Medicine, University of Vermont, Burlington, VT 05405, USA.

Many clinically based models are available for breast cancer risk assessment; however, these models are not particularly useful at the individual level, despite being designed with that intent. There is, therefore, a significant need for improved, precise individualized risk assessment. In this Research Perspective, we highlight commonly used clinical risk assessment models and recent scientific advances to individualize risk assessment using precision biomarkers. Genome-wide association studies have identified >100 single nucleotide polymorphisms (SNPs) associated with breast cancer risk, and polygenic risk scores (PRS) have been developed by several groups using this information. The ability of a PRS to improve risk assessment is promising; however, validation in both genetically and ethnically diverse populations is needed. Additionally, novel classes of biomarkers, such as microRNAs, may capture clinically relevant information based on epigenetic regulation of gene expression. Our group has recently identified a circulating-microRNA signature predictive of long-term breast cancer in a prospective cohort of high-risk women. While progress has been made, the importance of accurate risk assessment cannot be understated. Precision risk assessment will identify those women at greatest risk of developing breast cancer, thus avoiding overtreatment of women at average risk and identifying the most appropriate candidates for chemoprevention or surgical prevention.
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http://dx.doi.org/10.18632/aging.101803DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6402518PMC
February 2019

Participation of integrin β3 in osteoblast differentiation induced by titanium with nano or microtopography.

J Biomed Mater Res A 2019 06 23;107(6):1303-1313. Epub 2019 Feb 23.

Cell Culture Laboratory, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

The major role of integrins is to mediate cell adhesion but some of them are involved in the osteoblasts-titanium (Ti) interactions. In this study, we investigated the participation of integrins in osteoblast differentiation induced by Ti with nanotopography (Ti-Nano) and with microtopography (Ti-Micro). By using a PCR array, we observed that, compared with Ti-Micro, Ti-Nano upregulated the expression of five integrins in mesenchymal stem cells, including integrin β3, which increases osteoblast differentiation. Silencing integrin β3, using CRISPR-Cas9, in MC3T3-E1 cells significantly reduced the osteoblast differentiation induced by Ti-Nano in contrast to the effect on T-Micro. Concomitantly, integrin β3 silencing downregulated the expression of integrin αv, the parent chain that combines with other integrins and several components of the Wnt/β-catenin and BMP/Smad signaling pathways, all involved in osteoblast differentiation, only in cells cultured on Ti-Nano. Taken together, our results showed the key role of integrin β3 in the osteogenic potential of Ti-Nano but not of Ti-Micro. Additionally, we propose a novel mechanism to explain the higher osteoblast differentiation induced by Ti-Nano that involves an intricate regulatory network triggered by integrin β3 upregulation, which activates the Wnt and BMP signal transductions. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1303-1313, 2019.
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http://dx.doi.org/10.1002/jbm.a.36643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336872PMC
June 2019

The cancer-related transcription factor RUNX2 modulates expression and secretion of the matricellular protein osteopontin in osteosarcoma cells to promote adhesion to endothelial pulmonary cells and lung metastasis.

J Cell Physiol 2019 08 13;234(8):13659-13679. Epub 2019 Jan 13.

Millennium Institute on Immunology and Immunotherapy, University of Chile, Santiago, Chile.

Osteosarcomas are bone tumors that frequently metastasize to the lung. Aberrant expression of the transcription factor, runt-related transcription factor 2 (RUNX2), is a key pathological feature in osteosarcoma and associated with loss of p53 and miR-34 expression. Elevated RUNX2 may transcriptionally activate genes mediating tumor progression and metastasis, including the RUNX2 target gene osteopontin (OPN/SPP1). This gene encodes a secreted matricellular protein produced by osteoblasts to regulate bone matrix remodeling and tissue calcification. Here we investigated whether and how the RUNX2/OPN axis regulates lung metastasis of osteosarcoma. Importantly, RUNX2 depletion attenuates lung metastasis of osteosarcoma cells in vivo. Using next-generation RNA-sequencing, protein-based assays, as well as the loss- and gain-of-function approaches in selected osteosarcoma cell lines, we show that osteopontin messenger RNA levels closely correlate with RUNX2 expression and that RUNX2 controls the levels of secreted osteopontin. Elevated osteopontin levels promote heterotypic cell-cell adhesion of osteosarcoma cells to human pulmonary microvascular endothelial cells, but not in the presence of neutralizing antibodies. Collectively, these findings indicate that the RUNX2/OPN axis regulates the ability of osteosarcoma cells to attach to pulmonary endothelial cells as a key step in metastasis of osteosarcoma cells to the lung.
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http://dx.doi.org/10.1002/jcp.28046DOI Listing
August 2019

RUNX1-dependent mechanisms in biological control and dysregulation in cancer.

J Cell Physiol 2019 06 4;234(6):8597-8609. Epub 2018 Dec 4.

Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, Vermont.

The RUNX1 transcription factor has recently been shown to be obligatory for normal development. RUNX1 controls the expression of genes essential for proper development in many cell lineages and tissues including blood, bone, cartilage, hair follicles, and mammary glands. Compromised RUNX1 regulation is associated with many cancers. In this review, we highlight evidence for RUNX1 control in both invertebrate and mammalian development and recent novel findings of perturbed RUNX1 control in breast cancer that has implications for other solid tumors. As RUNX1 is essential for definitive hematopoiesis, RUNX1 mutations in hematopoietic lineage cells have been implicated in the etiology of several leukemias. Studies of solid tumors have revealed a context-dependent function for RUNX1 either as an oncogene or a tumor suppressor. These RUNX1 functions have been reported for breast, prostate, lung, and skin cancers that are related to cancer subtypes and different stages of tumor development. Growing evidence suggests that RUNX1 suppresses aggressiveness in most breast cancer subtypes particularly in the early stage of tumorigenesis. Several studies have identified RUNX1 suppression of the breast cancer epithelial-to-mesenchymal transition. Most recently, RUNX1 repression of cancer stem cells and tumorsphere formation was reported for breast cancer. It is anticipated that these new discoveries of the context-dependent diversity of RUNX1 functions will lead to innovative therapeutic strategies for the intervention of cancer and other abnormalities of normal tissues.
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http://dx.doi.org/10.1002/jcp.27841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6395522PMC
June 2019

Ethyl acetate and n-butanol fraction of Cissus quadrangularis promotes the mineralization potential of murine pre-osteoblast cell line MC3T3-E1 (sub-clone 4).

J Cell Physiol 2019 07 15;234(7):10300-10314. Epub 2018 Nov 15.

School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore, Pakistan.

In a sequel to investigate osteogenic potential of ethanolic extract of Cissus quadrangularis (CQ), the present study reports the osteoblast differentiation and mineralization potential of ethyl acetate (CQ-EA) and butanol (CQ-B) extracts of CQ on mouse pre-osteoblast cell line MC3T3-E1 (sub-clone 4) with an objective to isolate an antiosteoporotic compound. Growth curve, proliferation, and viability assays showed that both the extracts were nontoxic to the cells even at high concentration (100 µg/ml). The cell proliferation was enhanced at low concentrations (0.1 µg/ml and 1 µg/ml) of both the extracts. They also upregulated the osteoblast differentiation and mineralization processes in MC3T3-E1 cells as reflected by expression profile of osteoblast marker genes such as RUNX2, Osterix, Collagen (COL1A1), Alkaline Phosphatase (ALP), Integrin-related Bone Sialoprotein (IBSP), Osteopontin (OPN), and Osteocalcin (OCN). CQ-EA treatment resulted in early differentiation and mineralization as compared with the CQ-B treatment. These findings suggest that low concentrations of CQ-EA and CQ-B have proliferative and osteogenic properties. CQ-EA, however, is more potent osteogenic than CQ-B.
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http://dx.doi.org/10.1002/jcp.27707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7316083PMC
July 2019

Real-time detection of breast cancer at the cellular level.

J Cell Physiol 2019 05 26;234(5):5413-5419. Epub 2018 Oct 26.

Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Burlington, Vermont.

Novel optoelectronic instrumentation has been developed for the multispectral imaging of autofluorescence emitted by metabolic fluorophores. The images resolve individual cells while spectra are collected for each pixel in the images. These datacubes are generated at a rate of 10 per second-fast enough for surgical guidance. The data is processed in real time to provide a single color-coded image to the surgeon. To date, the system has been applied to fresh, ex vivo, human surgical specimens and has distinguished breast cancer from benign tissue. The approach is applicable to in vivo measurements of surgical margins and needle-based optical biopsies. Ongoing work demonstrates that the system has great potential for translation to a hand-held probe with high sensitivity and specificity.
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http://dx.doi.org/10.1002/jcp.27451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344234PMC
May 2019

Mll-COMPASS complexes mediate H3K4me3 enrichment and transcription of the osteoblast master gene Runx2/p57 in osteoblasts.

J Cell Physiol 2019 05 7;234(5):6244-6253. Epub 2018 Sep 7.

Faculty of Medicine and Faculty of Life Sciences, Institute of Biomedical Sciences, Universidad Andres Bello, Santiago, Chile.

Expression of Runx2/p57 is a hallmark of the osteoblast-lineage identity. Although several regulators that control the expression of Runx2/p57 during osteoblast-lineage commitment have been identified, the epigenetic mechanisms that sustain this expression in differentiated osteoblasts remain to be completely determined. Here, we assess epigenetic mechanisms associated with Runx2/p57 gene transcription in differentiating MC3T3 mouse osteoblasts. Our results show that an enrichment of activating histone marks at the Runx2/p57 P1 promoter is accompanied by the simultaneous interaction of Wdr5 and Utx proteins, both are components of COMPASS complexes. Knockdown of Wdr5 and Utx expression confirms the activating role of both proteins at the Runx2-P1 promoter. Other chromatin modifiers that were previously described to regulate Runx2/p57 transcription in mesenchymal precursor cells (Ezh2, Prmt5, and Jarid1b proteins) were not found to contribute to Runx2/p57 transcription in full-committed osteoblasts. We also determined the presence of additional components of COMPASS complexes at the Runx2/p57 promoter, evidencing that the Mll2/COMPASS- and Mll3/COMPASS-like complexes bind to the P1 promoter in osteoblastic cells expressing Runx2/p57 to modulate the H3K4me1 to H3K4me3 transition.
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http://dx.doi.org/10.1002/jcp.27355DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7261149PMC
May 2019

Suppression of Breast Cancer Stem Cells and Tumor Growth by the RUNX1 Transcription Factor.

Mol Cancer Res 2018 12 6;16(12):1952-1964. Epub 2018 Aug 6.

Department of Biochemistry and University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington, Vermont.

Breast cancer remains the most common malignant disease in women worldwide. Despite advances in detection and therapies, studies are still needed to understand the mechanisms underlying this cancer. Cancer stem cells (CSC) play an important role in tumor formation, growth, drug resistance, and recurrence. Here, it is demonstrated that the transcription factor RUNX1, well known as essential for hematopoietic differentiation, represses the breast cancer stem cell (BCSC) phenotype and suppresses tumor growth . The current studies show that BCSCs sorted from premalignant breast cancer cells exhibit decreased RUNX1 levels, whereas ectopic expression of RUNX1 suppresses tumorsphere formation and reduces the BCSC population. RUNX1 ectopic expression in breast cancer cells reduces migration, invasion, and tumor growth (57%) in mouse mammary fat pad. Mechanistically, RUNX1 functions to suppress breast cancer tumor growth through repression of CSC activity and direct inhibition of ZEB1 expression. Consistent with these cellular and biochemical results, clinical findings using patient specimens reveal that the highest RUNX1 levels occur in normal mammary epithelial cells and that low RUNX1 expression in tumors is associated with poor patient survival. IMPLICATIONS: The key finding that RUNX1 represses stemness in several breast cancer cell lines points to the importance of RUNX1 in other solid tumors where RUNX1 may regulate CSC properties.
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http://dx.doi.org/10.1158/1541-7786.MCR-18-0135DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6289193PMC
December 2018

Mitotic Gene Bookmarking: An Epigenetic Program to Maintain Normal and Cancer Phenotypes.

Mol Cancer Res 2018 11 12;16(11):1617-1624. Epub 2018 Jul 12.

Department of Biochemistry and University of Vermont Cancer Centre, University of Vermont, Burlington Vermont.

Reconfiguration of nuclear structure and function during mitosis presents a significant challenge to resume the next cell cycle in the progeny cells without compromising structural and functional identity of the cells. Equally important is the requirement for cancer cells to retain the transformed phenotype, that is, unrestricted proliferative potential, suppression of cell phenotype, and activation of oncogenic pathways. Mitotic gene bookmarking retention of key regulatory proteins that include sequence-specific transcription factors, chromatin-modifying factors, and components of RNA Pol (RNAP) I and II regulatory machineries at gene loci on mitotic chromosomes plays key roles in coordinate control of cell phenotype, growth, and proliferation postmitotically. There is growing recognition that three distinct protein types, mechanistically, play obligatory roles in mitotic gene bookmarking: (i) Retention of phenotypic transcription factors on mitotic chromosomes is essential to sustain lineage commitment; (ii) Select chromatin modifiers and posttranslational histone modifications/variants retain competency of mitotic chromatin for gene reactivation as cells exit mitosis; and (iii) Functional components of RNAP I and II transcription complexes (e.g., UBF and TBP, respectively) are retained on genes poised for reactivation immediately following mitosis. Importantly, recent findings have identified oncogenes that are associated with target genes on mitotic chromosomes in cancer cells. The current review proposes that mitotic gene bookmarking is an extensively utilized epigenetic mechanism for stringent control of proliferation and identity in normal cells and hypothesizes that bookmarking plays a pivotal role in maintenance of tumor phenotypes, that is, unrestricted proliferation and compromised control of differentiation. .
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http://dx.doi.org/10.1158/1541-7786.MCR-18-0415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6214712PMC
November 2018

Epithelial-to-mesenchymal transition and cancer stem cells contribute to breast cancer heterogeneity.

J Cell Physiol 2018 12 3;233(12):9136-9144. Epub 2018 Jul 3.

Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, Vermont.

Breast cancer is the most common cancer in women, and accounts for ~30% of new cancer cases and 15% of cancer-related deaths. Tumor relapse and metastasis are primary factors contributing to breast cancer-related deaths. Therefore, the challenge for breast cancer treatment is to sustain remission. A driving force behind tumor relapse is breast cancer heterogeneity (both intertumor, between different patients, and intratumor, within the same tumor). Understanding breast cancer heterogeneity is necessary to develop preventive interventions and targeted therapies. A recently emerging concept is that intratumor heterogeneity is driven by cancer stem cells (CSCs) that are capable of giving rise to a multitude of different cells within a tumor. Studies have highlighted linkage of CSC formation with epithelial-to-mesenchymal transition (EMT). In this review, we summarize the current understanding of breast cancer heterogeneity, links between EMT and CSCs, regulation of EMT by Runx transcription factors, and potential therapeutic strategies targeting these processes.
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http://dx.doi.org/10.1002/jcp.26847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6185773PMC
December 2018

Expression of the ectodomain-releasing protease ADAM17 is directly regulated by the osteosarcoma and bone-related transcription factor RUNX2.

J Cell Biochem 2018 11 19;119(10):8204-8219. Epub 2018 Jun 19.

Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.

Osteoblast differentiation is controlled by transcription factor RUNX2 which temporally activates or represses several bone-related genes, including those encoding extracellular matrix proteins or factors that control cell-cell, and cell-matrix interactions. Cell-cell communication in the many skeletal pericellular micro-niches is critical for bone development and involves paracrine secretion of growth factors and morphogens. This paracrine signaling is in part regulated by "A Disintegrin And Metalloproteinase" (ADAM) proteins. These cell membrane-associated metalloproteinases support proteolytic release ("shedding") of protein ectodomains residing at the cell surface. We analyzed microarray and RNA-sequencing data for Adam genes and show that Adam17, Adam10, and Adam9 are stimulated during BMP2 mediated induction of osteogenic differentiation and are robustly expressed in human osteoblastic cells. ADAM17, which was initially identified as a tumor necrosis factor alpha (TNFα) converting enzyme also called (TACE), regulates TNFα-signaling pathway, which inhibits osteoblast differentiation. We demonstrate that Adam17 expression is suppressed by RUNX2 during osteoblast differentiation through the proximal Adam17 promoter region (-0.4 kb) containing two functional RUNX2 binding motifs. Adam17 downregulation during osteoblast differentiation is paralleled by increased RUNX2 expression, cytoplasmic-nuclear translocation and enhanced binding to the Adam17 proximal promoter. Forced expression of Adam17 reduces Runx2 and Alpl expression, indicating that Adam17 may negatively modulate osteoblast differentiation. These findings suggest a novel regulatory mechanism involving a reciprocal Runx2-Adam17 negative feedback loop to regulate progression through osteoblast differentiation. Our results suggest that RUNX2 may control paracrine signaling through regulation of ectodomain shedding at the cell surface of osteoblasts by directly suppressing Adam17 expression.
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http://dx.doi.org/10.1002/jcb.26832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6317350PMC
November 2018

Corrigendum to "Pharmacological targeting of the mammalian clock reveals a novel analgesic for osteoarthritis-induced pain" [GENE 655 (2018) 1-12].

Gene 2019 01 12;680:105. Epub 2018 Jun 12.

Department of Bioengineering, University of Illinois at Chicago, IL, USA; Jesse Brown Veterans Affairs Medical Center (JBVAMC), Chicago, IL, USA. Electronic address:

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http://dx.doi.org/10.1016/j.gene.2018.06.013DOI Listing
January 2019

Nuclear organization mediates cancer-compromised genetic and epigenetic control.

Adv Biol Regul 2018 08 9;69:1-10. Epub 2018 May 9.

Department of Biochemistry and University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States. Electronic address:

Nuclear organization is functionally linked to genetic and epigenetic regulation of gene expression for biological control and is modified in cancer. Nuclear organization supports cell growth and phenotypic properties of normal and cancer cells by facilitating physiologically responsive interactions of chromosomes, genes and regulatory complexes at dynamic three-dimensional microenvironments. We will review nuclear structure/function relationships that include: 1. Epigenetic bookmarking of genes by phenotypic transcription factors to control fidelity and plasticity of gene expression as cells enter and exit mitosis; 2. Contributions of chromatin remodeling to breast cancer nuclear morphology, metabolism and effectiveness of chemotherapy; 3. Relationships between fidelity of nuclear organization and metastasis of breast cancer to bone; 4. Dynamic modifications of higher-order inter- and intra-chromosomal interactions in breast cancer cells; 5. Coordinate control of cell growth and phenotype by tissue-specific transcription factors; 6. Oncofetal epigenetic control by bivalent histone modifications that are functionally related to sustaining the stem cell phenotype; and 7. Noncoding RNA-mediated regulation in the onset and progression of breast cancer. The discovery of components to nuclear organization that are functionally related to cancer and compromise gene expression have the potential for translation to innovative cancer diagnosis and targeted therapy.
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http://dx.doi.org/10.1016/j.jbior.2018.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6102062PMC
August 2018

Thyroid Hormone Receptor β Suppression of RUNX2 Is Mediated by Brahma-Related Gene 1-Dependent Chromatin Remodeling.

Endocrinology 2018 06;159(6):2484-2494

Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont.

Thyroid hormone receptor β (TRβ) suppresses tumor growth through regulation of gene expression, yet the associated TRβ-mediated changes in chromatin assembly are not known. The chromatin ATPase brahma-related gene 1 (BRG1; SMARCA4), a key component of chromatin-remodeling complexes, is altered in many cancers, but its role in thyroid tumorigenesis and TRβ-mediated gene expression is unknown. We previously identified the oncogene runt-related transcription factor 2 (RUNX2) as a repressive target of TRβ. Here, we report differential expression of BRG1 in nonmalignant and malignant thyroid cells concordant with TRβ. BRG1 and TRβ have similar nuclear distribution patterns and significant colocalization. BRG1 interacts with TRβ, and together, they are part of the regulatory complex at the RUNX2 promoter. Loss of BRG1 increases RUNX2 levels, whereas reintroduction of TRβ and BRG1 synergistically decreases RUNX2 expression. RUNX2 promoter accessibility corresponded to RUNX2 expression levels. Inhibition of BRG1 activity increased accessibility of the RUNX2 promoter and corresponding expression. Our results reveal a mechanism of TRβ repression of oncogenic gene expression: TRβ recruitment of BRG1 induces chromatin compaction and diminishes RUNX2 expression. Therefore, BRG1-mediated chromatin remodeling may be obligatory for TRβ transcriptional repression and tumor suppressor function in thyroid tumorigenesis.
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http://dx.doi.org/10.1210/en.2018-00128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6692870PMC
June 2018