Runt Domain Transcription Factor Research Articles

Inactivation of runt domain transcription factor 3 via cytoplasmic existence under oxidative stress

Inactivation of runt domain transcription factor 3 via cytoplasmic existence under oxidative stress

Oxidative Stress-Mediated RUNX3 Mislocalization Occurs Via Jun Activation Domain-Binding Protein 1 and Histone Modification.

Runt domain transcription factor 3 (RUNX3) suppresses many different cancer types and is disabled by mutations, epigenetic repression, or cytoplasmic mislocalization. In this study, we investigated whether oxidative stress is associated with RUNX3 accumulation from the nucleus to the cytoplasm in terms of histone modification. Oxidative stress elevated histone deacetylase (HDAC) level and lowered that of histone acetyltransferase. In addition, oxidative stress decreased the expression of mixed lineage leukemia (MLL), a histone methyltransferase, but increased the expression of euchromatic histone-lysine N-methyltransferase 2 (EHMT2/G9a), which is also a histone methyltransferase. Moreover, oxidative stress-induced RUNX3 phosphorylation, Src activation, and Jun activation domain-binding protein 1 (JAB1) expression were inhibited by knockdown of HDAC and G9a, restoring the nuclear localization of RUNX3 under oxidative stress. Cytoplasmic RUNX3 localization was followed by oxidative stress-induced histone modification, activated Src along with RUNX3 phosphorylation, and induction of JAB1, resultingin RUNX3 inactivation.

Cytology, function and dynamics of stem and progenitor cells in decapod crustaceans.

Stem cells play key roles in development, tissue homeostasis, regeneration, ageing and diseases. Comprehensive reviews on stem cells are available for the determinately growing mammals and insects and some lower invertebrates like hydra but are rare for larger, indeterminately growing invertebrates that can live for many decades. This paper reviews the cytology, function and dynamics of stem and progenitor cells in the decapod crustaceans, a species-rich and ecologically and economically important animal group that includes mainly indeterminate growers but also some determinate growers. Further advantages of decapods for stem cell research are almost 1000-fold differences in body size and longevity, the regeneration of damaged appendages and the virtual absence of age-related diseases and tumours in the indeterminately growing species. The available data demonstrate that the Decapoda possess a remarkable variety of structurally and functionally different stem cells in embryos and larvae, and in the epidermis, musculature, haematopoietic tissue, heart, brain, hepatopancreas, olfactory sense organs and gonads of adults. Some of these seem to be rather continuously active over a lifetime but others are cyclically activated and silenced in periods of days, weeks and years, depending on the specific organ and function. Stem cell proliferation is triggered by signals related to development, moulting, feeding, reproduction, injury, infection, environmental enrichment and social status. Some regulatory pathways have already been identified, including the evolutionarily conserved GATA-binding and runt-domain transcription factors, the widespread neurotransmitter serotonin, the arthropod-specific hormone 20-hydroxyecdysone and the novel astakine growth factors. Knowledge of stem cells in decapods primarily refines our picture on the development, growth and maintenance of tissues and organs in this animal group. Cultured decapod stem cells have good potential for toxicity testing and virus research with practical relevance for aquaculture. Knowledge of stem cells in decapods also broadens our understanding of the evolution of stem cells and regeneration in the animal kingdom. The stem cells of long-lived, indeterminately growing decapods may hold the key to understanding how stem and progenitor cells function into old age without adverse side effects, possibly evoking new ideas for the development of anti-ageing and anti-cancer treatments in humans.

The Polymorphism at PLCB4 Promoter (rs6086746) Changes the Binding Affinity of RUNX2 and Affects Osteoporosis Susceptibility: An Analysis of Bioinformatics-Based Case-Control Study and Functional Validation.

PurposeGenome-wide association studies have identified numerous genetic variants that are associated with osteoporosis risk; however, most of them are present in the non-coding regions of the genome and the functional mechanisms are unknown. In this study, we aimed to investigate the potential variation in runt domain transcription factor 2 (RUNX2), which is an osteoblast-specific transcription factor that normally stimulates bone formation and osteoblast differentiation, regarding variants within RUNX2 binding sites and risk of osteoporosis in postmenopausal osteoporosis (PMOP).MethodsWe performed bioinformatics-based prediction by combining whole genome sequencing and chromatin immunoprecipitation sequencing to screen functional SNPs in the RUNX2 binding site using data from the database of Taiwan Biobank; Case-control studies with 651 postmenopausal women comprising 107 osteoporosis patients, 290 osteopenia patients, and 254 controls at Tri-Service General Hospital between 2015 and 2019 were included. The subjects were examined for bone mass density and classified into normal and those with osteopenia or osteoporosis by T-scoring with dual-energy X-ray absorptiometry. Furthermore, mRNA expression and luciferase reporter assay were used to provide additional evidence regarding the associations identified in the association analyses. Chi-square tests and logistic regression were mainly used for statistical assessment.ResultsThrough candidate gene approaches, 3 SNPs in the RUNX2 binding site were selected. A novel SNP rs6086746 in the PLCB4 promoter was identified to be associated with osteoporosis in Chinese populations. Patients with AA allele had higher risk of osteoporosis than those with GG+AG (adjusted OR = 6.89; 95% confidence intervals: 2.23–21.31, p = 0.001). Moreover, the AA genotype exhibited lower bone mass density (p < 0.05). Regarding mRNA expression, there were large differences in the correlation between PLCB4 and different RUNX2 alleles (Cohen’s q = 0.91). Functionally, the rs6086746 A allele reduces the RUNX2 binding affinity, thus enhancing the suppression of PLCB4 expression (p < 0.05).ConclusionsOur results provide further evidence to support the important role of the SNP rs6086746 in the etiology of osteopenia/osteoporosis, thereby enhancing the current understanding of the susceptibility to osteoporosis. We further studied the mechanism underlying osteoporosis regulation by PLCB4.

Runx Transcription Factors in T Cells-What Is Beyond Thymic Development?

Runx proteins (also known as Runt-domain transcription factors) have been studied for a long time as key regulators of cellular differentiation. RUNX2 has been described as essential for osteogenesis, whereas RUNX1 and RUNX3 are known to control blood cell development during different stages of cell lineage specification. However, recent studies show evidence of complex relationships between RUNX proteins, chromatin-modifying machinery, the cytoskeleton and different transcription factors in various non-embryonic contexts, including mature T cell homeostasis, inflammation and cancer. In this review, we discuss the diversity of Runx functions in mature T helper cells, such as production of cytokines and chemokines by different CD4 T cell populations; apoptosis; and immunologic memory acquisition. We then briefly cover recent findings about the contribution of RUNX1, RUNX2 and RUNX3 to various immunologic diseases. Finally, we discuss areas that require further study to better understand the role that Runx proteins play in inflammation and immunity.

Role of Runx2 in prostate development and stem cell function.

RUNX2, a critical transcription factor in bone development, is also expressed in prostate and breast where it has been linked to cancer progression and cancer stem cells. However, its role in normal prostate biology has not been previously examined. Selective growth of murine prostate epithelium under non-adherent conditions was used to enrich for stem cells. Expression of runt domain transcription factors, stem cell and prostate marker messenger RNAs (mRNAs) was determined by quantitative reverse transcription polymerase chain reaction. Effects of Runx2 loss and gain-of-function on prostate epithelial cells were assessed using cells isolated from Runx2loxp/loxp mice transduced with Adeno-Cre or by Adeno-Runx2 transduction of wild type cells. Cellular distribution of RUNX2 and prostate-associated proteins was assessed using immunofluorescence microscopy. In vivo Runx2 knock out was achieved by tamoxifen treatment of Nkx3.1CreERT; Runx2loxp/loxp mice. Prostate epithelium-derived spheroids, which are enriched in stem cells, were shown to contain elevated levels of Runx2 mRNA. Spheroid formation required Runx2 since adenovirus-Cre mediated knockout of Runx2 in prostatic epithelial cells from Runx2loxp/loxp mice severely reduced spheroid formation and stem cell markers while Runx2 overexpression was stimulatory. In vivo, Runx2 was detected during early prostate development (E16.5) and in adult mice where it was present in basal and luminal cells of ventral and anterior lobes. Prostate-selective deletion of Runx2 in tamoxifen-treated Nkx3.1CreERT; Runx2loxp/loxp mice severely inhibited growth and maturation of tubules in the anterior prostate and reduced expression of stem cell markers and prostate-associated genes. This study demonstrates an important role for Runx2 in prostate development that may be explained by actions in prostate epithelial stem cells.

RUNX1 Mutation Leads to Megakaryocyte-Primed Hematopoietic Stem Cell Expansion and Familial Platelet Disorder

Backgrounds: Recently it is shown that there exists a subpopulation of hematopoietic stem cells (HSCs) with relatively high expression of VWF and CD41+ at the apex of the hematopoietic stem cell hierarchy. This subset of HSCs, termed mega-HSCs, can give rise to megakaryocytes and platelets directly by bypassing the traditional trajectory of megakaryocyte development from HSC via MPP and MEP. To date, aside from phenotypic marker and transplantation studies, there has been limited understanding of the mechanisms involved in the regulation of mega-HSCs. Runx1 belongs to the RUNT domain transcription factors, and is a key regulator of hematopoiesis especially for the megakaryocyte and platelet differentiation. Loss of RUNX1 in mice causes thrombocytopenia through a blockage of megakaryocyte maturation. One allele RUNX1 loss-of-function mutation is associated with familial platelet disorder (FPD) with a predisposition to developing leukemia. Here we hypothesize that Runx1 plays a role in regulating mega-HSCs to impact on platelet generation, and correcting RUNX1 mutation that causes FPD can therapeutically rescue thrombocytopenia in a mouse model. Methods: We have examined the hematopoiesis and cellularity of various bone marrow (BM) stem/progenitor populations and peripheral blood (PB) in two mouse models. Firstly, conditional knock-out of Runx1flox/flox was mediated by Mx1-Cre upon poly I:C induction. Secondly, the tetracycline-inducible RUNX1 S291fsX300 mutation was knock-in at the collagen a1 locus and the mice was crossed to MLL-PTD knock-in. The mutant RUNX1 is only expressed when the mice are fed with doxycycline and the RUNX1 mutant is "corrected" upon doxycycline withdrawn. In the second model, PB and BM were also tracked after a removal of DOX-induced RUNX1 mutation. The LSK CD150+ HSCs from the mouse BM were isolated by FACS sorting, and 10x Genomics' single-cell RNA-seq (scRNA-seq) analyses were performed to define and track HSPCs. We applied the Louvain algorithm to the scRNA-seq data to identify the cell type clusters and annotated the cell types using the marker genes of each cell cluster. MAST was employed to identify the cell-type specific, differentially expressed genes. Results: In the Runx1 KO mice, two weeks after deletion of Runx1 platelet count showed an ~2-fold decrease to 400~600 k/ul in PB. In the LSK CD150+CD48- or the LSK CD34- FLT3- compartment of BM, the CD41+ mega-HSCs increased ~2-3 fold. In the RUNX1 mutant-on model, mutant mice developed thrombocytopenia 16 weeks after DOX induction with the average platelet count dropping to ~600 k/ul and being maintained at this level. In transplant recipients, the RUNX1 mutant-on mice contained drastically increased mega-HSCs compared with RUNX1 mutant-off mice, synchronous with a decrease of the platelet count in PB. Consistent with these observations, sc-RNAseq data show that in Runx1 KO, among the sequenced LSK CD150+ cells ~70% are HSCs and ~15% are MPP2. Among the HSCs, mega-primed HSCs consist ~33% while non-mega primed HSCs are ~67%. The mega-primed HSCs are distinct by virtual of upregulated platelet-related genes and relative dormant cell cycle status. In the RUNX1 mutant-on model, we found that among the sequenced LSK CD150+ cells ~50% are HSCs and ~12% are MPP2. Interestingly, the mega-primed HSCs are significantly increased in RUNX1 mut-on HSCs compared with mut-off HSCs. Similarly, we saw highly upregulated platelet-driven pathways in mega-HSCs in the mutant-on HSCs. Finally, one month after a withdraw of DOX from the RUNX1 mutant expressing mice when the RUNX1 mutant gene became undetectable, the platelet count returned from ~600 to ~1,000 k/ul in PB, a reversal of the thrombocytopenia phenotype caused by the RUNX1 S291fsX300 expression. Importantly, the correction of Runx1 mutation significantly decreased the proportion of mega-HSCs and restored platelet related pathways in this subset of HSCs. Conclusions: Mega-HSCs contain a high level of platelet-driven gene expression. In addition to its role in regulating the HSC-MPP-MEP mediated megakaryocyte development, RUNX1 is important in regulating mega-HSCs by maintaining proper expression of mega-platelet leaning genes. Correction of RUNX1 mutation that causes FPD can rescue mega-HSC population and revert FPD, providing a rationale for future treatment strategies by gene editing in RUNX1 mutation bearing FPD patients. Disclosures No relevant conflicts of interest to declare.

Emerging role of RUNX3 in the regulation of tumor microenvironment.

A number of genes have been therapeutically targeted to relieve cancer, but cancer relapse is still a growing issue. The concept that the surrounding tumor environment is critical for the progression of cancer may foster an answer to the issue of cancer malignancy. Runt domain transcription factors (RUNX1, 2, and 3) are evolutionarily conserved and have been intensively studied for their roles in normal development and pathological conditions. During tumor growth, a hypoxic microenvironment and infiltration of the tumor by immune cells are common phenomena. In this review, we briefly introduce the consequences of hypoxia and immune cell infiltration into the tumor microenvironment with a focus on RUNX3 as a critical regulator. Furthermore, based on our current knowledge of the functional role of RUNX3 in hypoxia and immune cell maintenance, a probable therapeutic intervention is suggested for the effective management of tumor growth and malignancy.

Cytoplasmic Localization of RUNX3 via Histone Deacetylase-Mediated SRC Expression in Oxidative-Stressed Colon Cancer Cells.

Runt domain transcription factor 3 (RUNX3) is a transcription factor that functions as a tumor suppressor. RUNX3 is frequently inactivated by epigenetic silencing or its protein mislocalization (cytoplasmic localization) in many cancer types. This study investigated whether oxidative stress induces redistribution of RUNX3 from the nucleus to the cytoplasm. The cytoplasmic localization of RUNX3 was associated with oxidative stress-induced RUNX3 phosphorylation at tyrosine residues via SRC activation. Moreover, oxidative stress increased expression of histone deacetylases (HDACs). RUNX3 phosphorylation and SRC expression induced by oxidative stress were inhibited by knockdown of HDAC1, restoring the nuclear localization of RUNX3 under oxidative stress. In conclusion, these results demonstrate that HDAC1- and SRC-mediated phosphorylation of RUNX3 induced by oxidative stress is associated with the cytoplasmic localization of RUNX3 and can lead to RUNX3 inactivation and carcinogenesis. J. Cell. Physiol. 232: 1914-1921, 2017. © 2016 Wiley Periodicals, Inc.

RUNX3 is oncogenic in natural killer/T-cell lymphoma and is transcriptionally regulated by MYC.

RUNX3, runt-domain transcription factor, is a master regulator of gene expression in major developmental pathways. It acts as a tumor suppressor in many cancers but is oncogenic in certain tumors. We observed upregulation of RUNX3 mRNA and protein expression in nasal-type extranodal natural killer (NK)/T-cell lymphoma (NKTL) patient samples and NKTL cell lines compared to normal NK cells. RUNX3 silenced NKTL cells showed increased apoptosis and reduced cell proliferation. Potential binding sites for MYC were identified in the RUNX3 enhancer region. Chromatin immunoprecipitation–quantitative PCR revealed binding activity between MYC and RUNX3. Co-transfection of the MYC expression vector with RUNX3 enhancer reporter plasmid resulted in activation of RUNX3 enhancer indicating that MYC positively regulates RUNX3 transcription in NKTL cell lines. Treatment with a small-molecule MYC inhibitor (JQ1) caused significant downregulation of MYC and RUNX3, leading to apoptosis in NKTL cells. The growth inhibition resulting from depletion of MYC by JQ1 was rescued by ectopic MYC expression. In summary, our study identified RUNX3 overexpression in NKTL with functional oncogenic properties. We further delineate that MYC may be an important upstream driver of RUNX3 upregulation and since MYC is upregulated in NKTL, further study on the employment of MYC inhibition as a therapeutic strategy is warranted.

Roles of RUNX in Hypoxia-Induced Responses and Angiogenesis.

During the past two decades, Runt domain transcription factors (RUNX1, 2, and 3) have been investigated in regard to their function, structural elements, genetic variants, and roles in normal development and pathological conditions. The Runt family proteins are evolutionarily conserved from Drosophila to mammals, emphasizing their physiological importance. A hypoxic microenvironment caused by insufficient blood supply is frequently observed in developing organs, growing tumors, and tissues that become ischemic due to impairment or blockage of blood vessels. During embryonic development and tumor growth, hypoxia triggers a stress response that overcomes low-oxygen conditions by increasing erythropoiesis and angiogenesis and triggering metabolic changes. This review briefly introduces hypoxic conditions and cellular responses, as well as angiogenesis and its related signaling pathways, and then describes our current knowledge on the functions and molecular mechanisms of Runx family proteins in hypoxic responses, especially in angiogenesis.

Roles of RUNX in Hippo Pathway Signaling.

The Runt-domain (RD) transcription factors (RUNX genes) are an important family of transcriptional mediators that interact with a variety of proteins including the Hippo pathway effector proteins, YAP and TAZ. In this chapter we focus on two examples of RUNX-TAZ/YAP interactions that have particular significance in human cancer. Specifically, recent evidence has found that RUNX2 cooperates with TAZ to promote epithelial to mesenchymal transition mediated by the soluble N-terminal ectodomain of E-Cadherin, sE-Cad. Contrastingly, in gastric cancer, RUNX3 acts as a tumor suppressor via inhibition of the YAP-TEAD complex and disruption of downstream YAP-mediated gene transcription and the oncogenic phenotype. The reports highlighted in this chapter add to the growing repertoire of instances of Hippo pathway crosstalk that have been identified in cancer. Elucidation of these increasingly complex interactions may help to identify novel strategies to target Hippo pathway dysregulation in human cancer.

PKCε is a regulator of hypertrophic differentiation of chondrocytes in osteoarthritis

Osteoarthritis (OA) is a common and highly debilitating degenerative disease whose complex pathogenesis and the multiplicity of the molecular processes involved, hinder its complete understanding. Protein Kinase C (PKC) novel isozyme PKCε recently proved to be an interesting molecule for further investigations as it can represent an intriguing, new actor in the acquisition of a OA phenotype by the chondrocyte. PKCε was modulated in primary chondrocytes from human OA patient knee cartilage samples by means of short hairpin RNA (ShRNA) and the expression of cartilage specific markers observed at mRNA and protein level. The involvement of Histone deacetylases (HDACs) signaling pathway was also investigated through the use of specific inhibitors MS-275 and Inhibitor VIII. PKCε loss induces up-regulation of Runt-domain transcription factor (RUNX2), Metalloproteinase 13 (MMP13) and Collagen X (COL10) as well as an enhanced calcium deposition in OA chondrocyte cultures. In parallel, PKCε knock-down also leads to SOX9 and Collagen II (COL2) down-modulation and to a lower deposition of glycosaminoglycans (GAGs) in the extracellular matrix (ECM). This novel regulatory role of PKCε over cartilage hypertrophic phenotype is exerted via an HDAC-mediated pathway, as HDAC2 and HDAC4 expression is modulated by PKCε. HDAC2 and HDAC4, in turn, are at least in part responsible for the modulation of the master transcription factors RUNX2 and SOX9, key regulators of chondrocyte phenotype. PKCε prevents the phenotypic progression of the OA chondrocyte, acting on cartilage specific markers through the modulation of the transcription factors SOX9 and RUNX2. The loss of PKCε enhances, in fact, the OA hypertrophic phenotype, with clear implications in the pathophysiology of the disease.

MicroRNA-130b functions as a tumor suppressor by regulating RUNX3 in epithelial ovarian cancer

AimTo evaluate the clinical significance of microRNA (miR)-130b–Runt domain transcription factor (RUNX3) axis and its effects on oncogenic phenotypes of human epithelial ovarian cancer (EOC). MethodsQRT-PCR was performed to detect the expression of miR-130b and RUNX3 mRNA in 100 EOC and 20 normal ovarian tissues. The associations between miR-130b and/or RUNX3 expression and various clinicopathological features of EOC patients were statistically analyzed. Then, the effects of miR-130b–RUNX3 axis on migration and invasion of EOC cells were assessed in vitro. ResultsmiR-130b expression was downregulated, while RUNX3 mRNA was upregulated, in EOC tissues compared to normal ovarian tissues (both P=0.001). Importantly, the expression level of miR-130b in EOC tissues was negatively correlated with that of RUNX3 mRNA significantly. Additionally, miR-130b-low and/or RUNX3-high expression were all closely correlated with advanced International Federation of Gynecology and Obstetrics (FIGO) stage (all P<0.05). Moreover, overexpression of miR-130b reduced the expression of RUNX3 and inhibited cancer cell migration and invasion of EOC cells, whereas knockdown of miR-130b increased the expression of RUNX3 and promoted cancer cell migration and invasion of EOC cells. After that, the impaired motility of the miR-130b overexpression cells was recovered partly by the expression of RUNX3. Furthermore, the knockdown of RUNX3 also gave rise to a decrease in cell migration and invasion. ConclusionOur data reveal that the dysregulation of miR-130b–RUNX3 axis may play important roles in EOC development and progression, and the loss of miR-130b may contribute to the malignant biological behavior of EOC cells via regulating the expression of RUNX3, implying their potentials as promising markers for predicting EOC progression and as candidate targets for gene therapy.

Long Noncoding RNA H19-Derived miR-675 Enhances Proliferation and Invasion via RUNX1 in Gastric Cancer Cells.

The lncRNA H19 and its mature product miR-675 have recently been shown to be upregulated and promote the progression of gastric cancer. However, the detailed function and underlying molecular mechanism of H19/miR-675 in the carcinogenesis of gastric cancer remains unclear. In this study, we found that H19 depended on miR-675 to enhance the proliferation and invasion of gastric cancer AGS cells, and the expression of miR-675 was positively correlated with H19 in patients with gastric cancer. Subsequently, the tumor-suppressor runt domain transcription factor 1 (RUNX1) was confirmed to be a downstream molecule of H19/miR-675 axis, since overexpression of H19 or miR-675 significantly decreased RUNX1 expression in AGS cells, and knockdown of H19 or miR-675 enhanced RUNX1 expression. More importantly, a series of assays further demonstrated that introduction of RUNX1 abrogated H19/miR-675-induced Akt/mTOR pathway activation and the following cellular proliferation and invasion of AGS cells. To our knowledge, this is the time to demonstrate that RUNX1 serves as a link between H19/miR-675 axis and Akt/mTOR signaling and is a pivotal mediator in gastric cancer progression induced by H19/miR-675. Thus, our study provides important clues for understanding the key roles of lncRNA-miRNA functional network and identifying new therapeutic targets for gastric cancer.

Abstract 2028: RUNX3 knockdown inhibited oral cancer-induced bone destruction via reducing TGF-β-dependent responses

Abstract Oral cancer ranks among the top 10 commonly diagnosed cancers. It easily invades underlying jaw bones and causes severe psychological and physical problems. When oral cancer cells infiltrate into jaw bones, survival rate of the patient is significantly decreased. Therefore, attention has been focused on molecular diagnostics and targeted therapy for oral cancer-induced bone destruction. However, there remains a lack of reliable biomarkers that can distinguish between bone-invasive and non-invasive oral cancers despite the recent advances in the field. The Runt domain transcription factor, RUNX3, has been found to be a tumor suppressor in many cancers through promoting transforming growth factor-β (TGF-β)-induced growth inhibition. However, the role of RUNX3 in oral cancer remains controversial. Here, we investigated whether RUNX3 has a critical role in oral cancer-induced bone destruction. In mice inoculated with RUNX3 knockdown oral cancer cells, tumor growth and bone destruction were significantly reduced. In oral cancer cells, RUNX3 knockdown significantly reduced cell viability in TGF-β-stimulated cells compared to unstimulated cells. Cell cycle analysis revealed that RUNX3 knockdown induced G1-specific cell-cycle arrest in the cancer cells without TGF-β treatment but G2-specific cell-cycle arrest in response to TGF-β treatment. RUNX3 knockdown inhibited cell migration and invasion in the absence or presence of TGF-β by changing both basal and TGF-β-induced level of epithelial-to-mesenchymal transition-related proteins. Furthermore, RUNX3 knockdown reduced parathyroid hormone-like protein expression, a major osteolytic factor, in oral cancer cells with or without TGF-β. We confirmed that RUNX3 knockdown in cancer cells decreased receptor activator of nuclear factor-kappaB ligand/osteoprotegerin ratio in osteoblastic hFOB1.19 cells treated with cancer cell-derived conditioned media. In summary, RUNX3 promotes oral cancer-induced bone destruction by enhancing interactions between cancer cells and bone cells as well as promoting malignant behavior of cancer cells. Therefore, RUNX3 may be a useful biomarker and potential therapeutic target for bone invasion of oral cancer. Citation Format: Junhee Park, Won-Yoon Chung, Kwang-Kyun Park. RUNX3 knockdown inhibited oral cancer-induced bone destruction via reducing TGF-β-dependent responses. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2028. doi:10.1158/1538-7445.AM2015-2028

Incoherent feed-forward regulatory loops control segregation of C-mechanoreceptors, nociceptors, and pruriceptors.

Mammalian skin is innervated by diverse, unmyelinated C fibers that are associated with senses of pain, itch, temperature, or touch. A key developmental question is how this neuronal cell diversity is generated during development. We reported previously that the runt domain transcription factor Runx1 is required to coordinate the development of these unmyelinated cutaneous sensory neurons, including VGLUT3(+) low-threshold c-mechanoreceptors (CLTMs), MrgprD(+) polymodal nociceptors, MrgprA3(+) pruriceptors, MrgprB4(+) c-mechanoreceptors, and others. However, how these Runx1-dependent cutaneous sensory neurons are further segregated is poorly illustrated. Here, we find that the Runx1-dependent transcription factor gene Zfp521 is expressed in, and required for establishing molecular features that define, VGLUT3(+) CLTMs. Furthermore, Runx1 and Zfp521 form a classic incoherent feedforward loop (I-FFL) in controlling molecular identities that normally belong to MrgprD(+) neurons, with Runx1 and Zfp51 playing activator and repressor roles, respectively (in genetic terms). A knock-out of Zfp521 allows prospective VGLUT3 lineage neurons to acquire MrgprD(+) neuron identities. Furthermore, Runx1 might form other I-FFLs to regulate the expression of MrgprA3 and MrgprB4, a mechanism preventing these genes from being expressed in Runx1-persistent VGLUT3(+) and MrgprD(+) neurons. The evolvement of these I-FFLs provides an explanation for how modality-selective sensory subtypes are formed during development and may also have intriguing implications for sensory neuron evolution and sensory coding.

YAP/TAZ for cancer therapy: opportunities and challenges (review).

YAP (Yes-associated protein) and its paralog TAZ (transcriptional co-activator with PDZ-binding motif) are the main downstream effectors of the Hippo signaling pathway. This pathway is an evolutionally conserved signal cascade, which plays pivotal roles in organ size control and tumorigenesis from Drosophila to mammals. Functionally, when the Hippo pathway is activated, YAP and TAZ will be sequestered in the cytoplasm and degraded. Conversely, when the Hippo pathway is deactivated, YAP and TAZ will translocate into nucleus and promote transcription of downstream genes by forming complexes with transcription factors, such as transcriptional enhancer factors (TEF; also referred to as TEAD), runt-domain transcription factors (Runx) and others. Most of these transcription factors belong to growth promoting or apoptosis-inhibition genes. It has been reported that the deactivation of the Hippo pathway, as well as up-regulation of YAP and TAZ was observed in many human cancers with a high frequency, which suggests that the Hippo pathway may be a potent target for developing anticancer drugs. In this review, we provide an overview of the Hippo pathway and summarize recent advances with respect to the role of YAP and TAZ in Hippo signaling pathway and cancer development. Furthermore, we describe the opportunities and challenges for exploit YAP and TAZ as potential therapeutic targets in cancer.

Lineage-specific RUNX3 hypomethylation marks the preneoplastic immune component of gastric cancer.

Runt domain transcription factor 3 (RUNX3) is widely regarded as a tumour-suppressor gene inactivated by DNA hypermethylation of its canonical CpG (cytidine-phosphate-guanidine) island (CGI) promoter in gastric cancer (GC). Absence of RUNX3 expression from normal gastric epithelial cells (GECs), the progenitors to GC, coupled with frequent RUNX3 overexpression in GC progression, challenge this longstanding paradigm. However, epigenetic models to better describe RUNX3 deregulation in GC have not emerged. Here, we identify lineage-specific DNA methylation at an alternate, non-CGI promoter (P1) as a new mechanism of RUNX3 epigenetic control. In normal GECs, P1 was hypermethylated and repressed, whereas in immune lineages P1 was hypomethylated and widely expressed. In human GC development, we detected aberrant P1 hypomethylation signatures associated with the early inflammatory, preneoplastic and tumour stages. Aberrant P1 hypomethylation was fully recapitulated in mouse models of gastric inflammation and tumorigenesis. Cell sorting showed that P1 hypomethylation reflects altered cell-type composition of the gastric epithelium/tumour microenvironment caused by immune cell recruitment, not methylation loss. Finally, via long-term culture of gastric tumour epithelium, we revealed that de novo methylation of the RUNX3 canonical CGI promoter is a bystander effect of oncogenic immortalization and not likely causal in GC pathogenesis as previously argued. We propose a new model of RUNX3 epigenetic control in cancer, based on immune-specific, non-CGI promoter hypomethylation. This novel epigenetic signature may have utility in early detection of GC and possibly other epithelial cancers with premalignant immune involvement.

Gene promoter polymorphism of RUNX2 and risk of osteoporosis in postmenopausal Indonesian women.

Objectives:Osteoporosis is a metabolic bone disease of reduced bone mass density (BMD) and elevated risk of fracture due to an imbalance in bone formation and resorption. The risk and incidence of osteoporosis increase towards advanced age, particularly in postmenopausal women, and the risk is known to be affected by the variation in the expression of the associated regulatory genes. This work aimed to clarify the impact of variation in RUNX2 (runt domain transcription factor 2), which is an osteoblast-specific transcription factor that normally stimulates bone formation and osteoblast differentiation, regarding single-nucleotide polymorphism within RUNX2 promoter (P1) and risk of osteoporosis in postmenopausal Indonesian women.Methods:Using DNA sampling from blood, the variation at the single-nucleotide polymorphism (-330, G→T, rs59983488) at the RUNX2 P1 promoter was investigated using polymerase chain reaction–restriction fragment length polymorphism for 180 consenting postmenopausal Indonesian women. The subjects were examined for bone mass density and classification to normal and those with osteopenia or osteoporosis by T-scoring with dual-energy X-ray absorptiometry. Chi-square testing and logistic regression were mainly used for statistical assessment.Results:The results showed a general trend with increased risk of osteoporosis associated with the genotype TT (mutant type) and the corresponding T allele of the tested polymorphism of RUNX2 promoter P1. The trend was, however, not significant in multivariate testing adjusted for age and time after menopause.Conclusion:To confirm the potential risk with TT genotype would require testing of a much larger sample of subjects. As the tested single-nucleotide polymorphism only represents one of the relevant candidate locations of RUNX2, the results are taken nevertheless to suggest an impact by overall RUNX2 variation in the risk of osteoporosis in Indonesian postmenopausal women.