Cancer Cell-Type-Dependent Modifications of Metastatic Parameters by SLIT2-ROBO1 and RHOA cAMP Signaling in Response to TGFß1 and FGF2.

The epithelial to mesenchymal transition (EMT) is a multistep process involving structural and functional alterations that are required for cancer metastasis, as well as loss of epithelial markers (e.g., E-cadherin/CDH1) and gain of mesenchymal markers (e.g., N-cadherin/CDH2, vimentin/VIM). Pathological events modify cell-cell interactions, cell-matrix adhesion and extra cellular matrix integrity leading to cell migration, evasion from the primary tumor and augmented invasiveness in the metastatic niche. This transformation is modulated by multiple paracrine factors (e.g., chemokines, growth factor), as well as SLIT2-ROBO1 signaling that collectively regulate expression of RHO GTPases (e.g., RHOA) and EMT marker genes. Yet, the roles of SLIT proteins in cancer remain enigmatic. In some cancer types, SLIT2 is anti-tumorigenic, while in other cancers it contributes towards the metastatic phenotype. Here we investigated the ambivalent metastatic activity of SLIT2 by analyzing how cAMP/RHOA signal transduction modulates SLIT-ROBO controlled metastatic parameters in response to the phosphodiesterase inhibitor IBMX (3-isobutyl-1-methylxanthine) and paracrine factors (TGF-ß/TGFß1 and FGF2). Upon SLIT2 administration cell migration and proliferation increases in colon cancer cells and decreases in cervical cancer cells, while altering cell morphology and proliferation in both cancer types. These effects are reinforced by TGF-ß/TGFß1 and FGF2, but attenuated by elevation of cAMP with IBMX, depending on the cancer cell type. Our data indicate that SLIT2 represents a potential biomarker for cancer diagnosis, prognosis, and therapy.

Evidence-Based Storytelling for a Strategic Roadmap to Promote Cancer Prevention via Adolescent HPV Vaccination in Northern New England.

Vaccination rates for the human papillomavirus (HPV) among rural youth in northern New England lag those of more urbanized areas. Reasons include a lack of available medical offices, time constraints, perceptions of vaccines and HPV, and, to a smaller degree, delays caused by the COVID-19 pandemic. We have a responsibility to increase vaccinations in these communities. To do so, vaccination experts recommend addressing the three C's of vaccination hesitation: confidence, complacency, and convenience. With this framework as our foundation, in this article we detail a plan to address these important elements, and we add several more C's: clinics, communication, collaboration, community, capacity, and commitment to the list as we discuss the essential pieces-human, infrastructural, and perceptual-needed to create and promote successful, community-supported, school-based HPV vaccination clinics to serve youths aged nine to 18. We then integrate research and storytelling science into an innovative Persuasion Playbook, a guide for local opinion leaders to use in creating evidence-based, pro-vaccine messages on the community level to promote the clinics via evidence-based, pro-vaccination messages.

RUNX2 as a Prognostic Factor in Human Cancers.

The RUNX2 transcription factor was discovered as an essential transcriptional regulator for commitment to osteoblast lineage cells and bone formation. Expression of RUNX2 in other tissues, such as breast, prostate, and lung, has been linked to oncogenesis, cancer progression, and metastasis. In this study, we sought to determine the extent of RUNX2 involvement in other tumors using a pan-cancer analysis strategy. We correlated RUNX2 expression and clinical-pathological parameters in human cancers by interrogating publicly available multiparameter clinical data. Our analysis demonstrated that altered RUNX2 expression or function is associated with several cancer types from different tissues. We identified three tumor types associated with increased RUNX2 expression and four other tumor types associated with decreased RUNX2 expression. Our pan-cancer analysis for RUNX2 revealed numerous other discoveries for RUNX2 regulation of different cancers identified in each of the pan-cancer databases. Both up and down regulation of RUNX2 was observed during progression of specific types of cancers in promoting the distinct types of cancers.

Multispectral Imaging of Metabolic Fluorophores: Comparing In Vivo and Fresh Ex Vivo Tissue.

The enhanced uptake of glucose by cancer cells via aerobic glycolysis occurs when the lactic acid pathway is favored over the citric acid cycle. The lactic acid cycle in cancer cells influences the cytosolic concentration of metabolic fluorophores including NADH (the reduced form of nicotinamide adenine dinucleotide) and flavin adenine dinucleotide (FAD). In particular, the literature has shown that breast cancer influences the relative magnitude of fluorescence from NADH and FAD. A multispectral imaging system has been developed for rapid non-destructive imaging of intrinsic fluorescence in tissue. This paper compares in vivo data to fresh ex vivo data gathered as a function of time in mouse models. The data indicate that, if measured within 30 min of excision, a cancer diagnosis in fresh ex vivo tissue correlates with a cancer diagnosis in in vivo tissue. These results justify a plan to evaluate fresh ex vivo human tissue to quantify the sensitivity and specificity of the multispectral system.

Bromodomain Proteins Epigenetically Regulate the Mitotically Associated lncRNA MANCR in Triple Negative Breast Cancer Cells.

Long non-coding RNA (lncRNA)-mediated control of gene expression contributes to regulation of biological processes that include proliferation and phenotype, as well as compromised expression of genes that are functionally linked to cancer initiation and tumor progression. lncRNAs have emerged as novel targets and biomarkers in breast cancer. We have shown that mitotically associated lncRNA MANCR is expressed in triple-negative breast cancer (TNBC) cells and that it serves a critical role in promoting genome stability and survival in aggressive breast cancer cells. Using an siRNA strategy, we selectively depleted BRD2, BRD3, and BRD4, singly and in combination, to establish which bromodomain proteins regulate MANCR expression in TNBC cells. Our findings were confirmed by using in situ hybridization combined with immunofluorescence analysis that revealed BRD4, either alone or with BRD2 and BRD3, can support MANCR regulation of TNBC cells. Here we provide evidence for MANCR-responsive epigenetic control of super enhancers by histone modifications that are required for gene transcription to support cell survival and expression of the epithelial tumor phenotype in triple negative breast cancer cells.

Fundamentals and Translational Applications of Stem Cells and Biomaterials in Dental, Oral and Craniofacial Regenerative Medicine.

Regenerative dental medicine continuously expands to improve treatments for prevalent clinical problems in dental and oral medicine. Stem cell based translational opportunities include regenerative therapies for tooth restoration, root canal therapy, and inflammatory processes (e.g., periodontitis). The potential of regenerative approaches relies on the biological properties of dental stem cells. These and other multipotent somatic mesenchymal stem cell (MSC) types can in principle be applied as either autologous or allogeneic sources in dental procedures. Dental stem cells have distinct developmental origins and biological markers that determine their translational utility. Dental regenerative medicine is supported by mechanistic knowledge of the molecular pathways that regulate dental stem cell growth and differentiation. Cell fate determination and lineage progression of dental stem cells is regulated by multiple cell signaling pathways (e.g., WNTs, BMPs) and epigenetic mechanisms, including DNA modifications, histone modifications, and non-coding RNAs (e.g., miRNAs and lncRNAs). This review also considers a broad range of novel approaches in which stem cells are applied in combination with biopolymers, ceramics, and composite materials, as well as small molecules (agonistic or anti-agonistic ligands) and natural compounds. Materials that mimic the microenvironment of the stem cell niche are also presented. Promising concepts in bone and dental tissue engineering continue to drive innovation in dental and non-dental restorative procedures.

A MicroRNA Approach to Evaluating Elevated Prostate Cancer Risk in Cancer-Free Men.

Objective criteria are required for prostate cancer (PCa) risk assessment, treatment decisions, evaluation of therapy, and initial indications of recurrence. Circulating microRNAs were utilized as biomarkers to distinguish PCa patients from cancer-free subjects or those encountering benign prostate hyperplasia. A panel of 60 microRNAs was developed with established roles in PCa initiation, progression, metastasis, and recurrence. Utilizing the FirePlex® platform for microRNA analysis, we demonstrated the efficacy and reproducibility of a rapid, high-throughput, serum-based assay for PCa biomarkers that circumvents the requirement for extraction and fractionation of patient specimens supporting feasibility for expanded clinical research and diagnostic applications.

Hinfp is a guardian of the somatic genome by repressing transposable elements.

Germ cells possess the Piwi-interacting RNA pathway to repress transposable elements and maintain genome stability across generations. Transposable element mobilization in somatic cells does not affect future generations, but nonetheless can lead to pathological outcomes in host tissues. We show here that loss of function of the conserved zinc-finger transcription factor Hinfp causes dysregulation of many host genes and derepression of most transposable elements. There is also substantial DNA damage in somatic tissues of Drosophila after loss of Hinfp. Interference of transposable element mobilization by reverse-transcriptase inhibitors can suppress some of the DNA damage phenotypes. The key cell-autonomous target of Hinfp in this process is Histone1, which encodes linker histones essential for higher-order chromatin assembly. Transgenic expression of Hinfp or Histone1, but not Histone4 of core nucleosome, is sufficient to rescue the defects in repressing transposable elements and host genes. Loss of Hinfp enhances Ras-induced tissue growth and aging-related phenotypes. Therefore, Hinfp is a physiological regulator of Histone1-dependent silencing of most transposable elements, as well as many host genes, and serves as a venue for studying genome instability, cancer progression, neurodegeneration, and aging.

Disrespectful and inadequate palliative care to transgender persons.

OBJECTIVES: The purpose of this study was to describe disrespectful, inadequate, and abusive care to seriously ill patients who identify as transgender and their partners. METHODS: A cross-sectional mixed methods study was conducted. The sample included 865 nurses, physicians, social workers, and chaplains. Respondents were asked whether they had observed disrespectful, inadequate, or abusive care due to the patient being transgender and to describe such care. RESULTS: Of the 21.3% of participants who reported observing discriminatory care to a transgender patient, 85.3% had observed disrespectful care, 35.9% inadequate care, and 10.3% abusive care. Disrespectful care included insensitivity; rudeness, ridicule, and gossip by staff; not acknowledging or accepting the patient's gender identity or expression; privacy violations; misgendering; and using the incorrect name. Inadequate care included denying, delaying, or rushing care; ignorance of appropriate medical and other care; and marginalizing or ignoring the spouse/partner. SIGNIFICANCE OF RESULTS: These findings illustrate discrimination faced by seriously ill transgender patients and their spouse/partners. Providers who are disrespectful may also deliver inadequate care to transgender patients, which may result in mistrust of providers and the health-care system. Inadequate care due to a patient's or spouse's/partner's gender identity is particularly serious. Dismissing spouses/partners as decision-makers or conferring with biological family members against the patient's wishes may result in unwanted care and constitute a Health Insurance Portability and Accountability Act of 1996 (HIPAA) violation. Institutional policies and practices should be assessed to determine the degree to which they are affirming to both patients and staff, and revised if needed. Federal and state civil rights legislation protecting the LGBTQ+ community are needed, particularly given the rampant transphobic legislation and the majority of states lacking civil rights laws protecting LGBTQ+ people. Training healthcare professionals and staff to become competent and comfortable treating transgender patients is critical to providing optimal care for these seriously ill patients and their spouse/partner.

peaksat: an R package for ChIP-seq peak saturation analysis.

BACKGROUND: Epigenomic profiling assays such as ChIP-seq have been widely used to map the genome-wide enrichment profiles of chromatin-associated proteins and posttranslational histone modifications. Sequencing depth is a key parameter in experimental design and quality control. However, due to variable sequencing depth requirements across experimental conditions, it can be challenging to determine optimal sequencing depth, particularly for projects involving multiple targets or cell types. RESULTS: We developed the peaksat R package to provide target read depth estimates for epigenomic experiments based on the analysis of peak saturation curves. We applied peaksat to establish the distinctive read depth requirements for ChIP-seq studies of histone modifications in different cell lines. Using peaksat, we were able to estimate the target read depth required per library to obtain high-quality peak calls for downstream analysis. In addition, peaksat was applied to other sequence-enrichment methods including CUT&RUN and ATAC-seq. CONCLUSION: peaksat addresses a need for researchers to make informed decisions about whether their sequencing data has been generated to an adequate depth and subsequently sufficient meaningful peaks, and failing that, how many more reads would be required per library. peaksat is applicable to other sequence-based methods that include calling peaks in their analysis.

Raising the HPV Vaccination Rate in Rural Northern New England Using Local Opinion Leaders.

The human papillomavirus is associated with a range of cancers. A vaccine introduced in 2006 has dramatically decreased the incidence of these cancers, but Americans still experience over 47,000 new cases of HPV-related cancers each year. The situation is worse in rural areas, where vaccination rates lag the national average, making HPV a significant health disparity issue. This article lays out an evidence-based HPV vaccine-promotion strategy that will serve as part of a campaign to improve health equity in rural northern New England in a process that is repeatable and sustainable. The campaign includes the following elements: partnerships with state departments of health and trusted community opinion leaders, evidence-based storytelling, local social media, traditional media, and school-based pop-up vaccination clinics. Borrowing from marketing and social marketing frameworks and guided by public health perspectives, we begin with psychographic and geodemographic information about our target audience, followed by a discussion about relevant models, frameworks, and research related to persuasive storytelling. We conclude with the outline of a guidebook to foster the creation of persuasive stories as part of a sustainable, replicable HPV vaccination campaign.

Spatiotemporal Epigenetic Control of the Histone Gene Chromatin Landscape during the Cell Cycle.

Higher-order genomic organization supports the activation of histone genes in response to cell cycle regulatory cues that epigenetically mediates stringent control of transcription at the G1/S-phase transition. Histone locus bodies (HLBs) are dynamic, non-membranous, phase-separated nuclear domains where the regulatory machinery for histone gene expression is organized and assembled to support spatiotemporal epigenetic control of histone genes. HLBs provide molecular hubs that support synthesis and processing of DNA replication-dependent histone mRNAs. These regulatory microenvironments support long-range genomic interactions among non-contiguous histone genes within a single topologically associating domain (TAD). HLBs respond to activation of the cyclin E/CDK2/NPAT/HINFP pathway at the G1/S transition. HINFP and its coactivator NPAT form a complex within HLBs that controls histone mRNA transcription to support histone protein synthesis and packaging of newly replicated DNA. Loss of HINFP compromises H4 gene expression and chromatin formation, which may result in DNA damage and impede cell cycle progression. HLBs provide a paradigm for higher-order genomic organization of a subnuclear domain that executes an obligatory cell cycle-controlled function in response to cyclin E/CDK2 signaling. Understanding the coordinately and spatiotemporally organized regulatory programs in focally defined nuclear domains provides insight into molecular infrastructure for responsiveness to cell signaling pathways that mediate biological control of growth, differentiation phenotype, and are compromised in cancer.

Disrespectful and inadequate palliative care to lesbian, gay, and bisexual patients.

OBJECTIVES: The study aims to describe inadequate, disrespectful, and abusive palliative and hospice care received by lesbian, gay, and bisexual (LGB) patients and their spouses/partners due to their sexual orientation or gender identity. METHODS: A national sample of 865 healthcare professionals recruited from palliative and hospice care professional organizations completed an online survey. Respondents were asked to describe their observations of inadequate, disrespectful, or abusive care to LGB patients and their spouses/partners. RESULTS: There were 15.6% who reported observing disrespectful care to LGB patients, 7.3% observed inadequate care, and 1.6% observed abusive care; 43% reported discriminatory care toward the spouses/partners. Disrespectful care to LGB patients included insensitive and judgmental attitudes and behaviors, gossip and ridicule, and disrespect of the spouse/partner. Inadequate care included denial of care; care that was delayed incomplete, or rushed; dismissive or antagonistic treatment; privacy and confidentiality violations; and dismissive treatment of the spouse/partner. SIGNIFICANCE OF RESULTS: These findings provide evidence of discrimination faced by LGB patients and partners while receiving care for serious illness. Hospice and palliative care programs should promote respectful, inclusive, and affirming care for the lesbian, gay, bisexual, transgender, and queer (LGBTQ) community, including policies and practices that are welcoming and supportive to both employees and patients. Staff at all levels should be trained to create safe and respectful environments for LGBTQ patients and their families.

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

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-VPRBMP-9+, 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-VPRBMP-9+ displayed significant changes in the expression of a panel of genes involved in TGF-ß/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-VPRBMP-9+ 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.

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

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/Cbfß complex formation. The Hif-2α-mediated-Runx2 degradation could be rescued by Cbfß transfection due to the increase of Runx2/Cbfß 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/Cbfß complex formation and consequential regulatory activity.

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

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.

Ezh2-dependent H3K27me3 modification dynamically regulates vitamin D3-dependent epigenetic control of CYP24A1 gene expression in osteoblastic cells.

Epigenetic control is critical for the regulation of gene transcription in mammalian cells. Among the most important epigenetic mechanisms are those associated with posttranslational modifications of chromosomal histone proteins, which modulate chromatin structure and increased accessibility of promoter regulatory elements for competency to support transcription. A critical histone mark is trimethylation of histone H3 at lysine residue 27 (H3K27me3), which is mediated by Ezh2, the catalytic subunit of the polycomb group complex PRC2 to repress transcription. Treatment of cells with the active vitamin D metabolite 1,25(OH)2 D3 , results in transcriptional activation of the CYP24A1 gene, which encodes a 24-hydroxylase enzyme, that is, essential for physiological control of vitamin D3 levels. We report that the Ezh2-mediated deposition of H3K27me3 at the CYP24A1 gene promoter is a requisite regulatory component during transcriptional silencing of this gene in osteoblastic cells in the absence of 1,25(OH)2 D3 . 1,25(OH)2 D3 dependent transcriptional activation of the CYP24A1 gene is accompanied by a rapid release of Ezh2 from the promoter, together with the binding of the H3K27me3-specific demethylase Utx/Kdm6a and thereby subsequent erasing of the H3K27me3 mark. Importantly, we find that these changes in H3K27me3 enrichment at the CYP24A1 gene promoter are highly dynamic, as this modification is rapidly reacquired following the withdrawal of 1,25(OH)2 D3 .

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

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)2 D3 ) 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)2 D3 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)2 D3 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)2 D3 .

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

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.

The epigenetic reader Brd4 is required for osteoblast differentiation.

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.