Oncogenic RUNX3: A Link between p53 Deficiency and MYC Dysregulation

RUNX3-activated apelin signaling inhibits cell proliferation and fibrosis in diabetic nephropathy by regulation of the SIRT1/FOXO pathway

BACKGROUND

Diabetic nephropathy is a major secondary cause of end-stage renal disease. Apelin plays an important role in the development of DN. Understanding the exact mechanism of Apelin can help expand the means of treating DN.

METHODS

Male C57BL/6 mice was used and STZ treatment was implemented for DN model establishment. Lentivirus systems including Lv-sh-RUNX3 and Lv-Apelin were obtained to knockdown RUNX3 and overexpress Apelin, respectively. A total of 36 mice were divided into 6 groups (n = 6 in each group): control, DN, DN + LV-Vector, DN + Lv-Apelin, DN + LV-Apelin + LV-sh-NC and DN + Lv-Apelin + Lv-sh-RUNX3 group. In vitro studies were performed using mesangial cells. Cell viability and proliferation was assessed through CCK8 and EDU analysis. Hematoxylin and eosin staining as well as Masson staining was implemented for histological evaluation. RT-qPCR was conducted for measuring relative mRNA levels, and protein expression was detected by western blotting. The interaction between SIRT1 and FOXO were verified by co-immunoprecipitations, and relations between RUNX3 and Apelin were demonstrated by dual luciferase report and chromatin immunoprecipitation.

RESULTS

The DN group exhibited significantly lower Apelin expression compared to control (p < 0.05). Apelin overexpression markedly improved blood glucose, renal function indicators, ameliorated renal fibrosis and reduced fibrotic factor expression (p < 0.05) in the DN group, accompanied by elevated sirt1 levels and diminished acetylated FOXO1/FOXO3a (p < 0.05). However, RUNX3 knockdown combined with Apelin overexpression abrogated these beneficial effects, leading to impaired renal function, exacerbated fibrosis, increased fibrotic factor expression and acetylated FOXO1/FOXO3a versus Apelin overexpression alone (p < 0.05). In mesangial cells under high glucose, Apelin overexpression significantly inhibited cell proliferation and fibrotic factor production (p < 0.05). Conversely, RUNX3 interference enhanced cell proliferation and the secretion of fibrotic factors. (p < 0.05). Remarkably, combining Apelin overexpression with RUNX3 interference reversed the proliferation and fibrosis induced by RUNX3 interference (p < 0.05). Mechanistic studies revealed RUNX3 binds to the Apelin promoter, with the 467-489 bp site1 as the primary binding region, and SIRT1 physically interacts with FOXO1 and FOXO3a in mesangial cells.

CONCLUSION

RUNX3 activated Apelin and regulated the SIRT1/FOXO signaling pathway, resulting in the suppressed cell proliferation and fibrosis in diabetic nephropathy. Apelin is a promising endogenous therapeutic target for anti-renal injury and anti-fibrosis in diabetic nephropathy. RUNX3 may serve as an endogenous intervention target for diseases related to Apelin deficiency.

Myc upregulates Ggct, γ-glutamylcyclotransferase to promote development of p53-deficient osteosarcoma

Osteosarcoma (OS) in humans is characterized by alterations in the TP53 gene. In mice, loss of p53 triggers OS development, for which c-Myc (Myc) oncogenicity is indispensable. However, little is known about which genes are targeted by Myc to promote tumorigenesis. Here, we examined the role of γ-glutamylcyclotransferase (Ggct) which is a component enzyme of the γ-glutamyl cycle essential for glutathione homeostasis, in human and mouse OS development. We found that GGCT is a poor prognostic factor for human OS, and that deletion of Ggct suppresses p53-deficient osteosarcomagenesis in mice. Myc upregulates Ggct directly by binding to the Ggct promoter, and deletion of a Myc binding site therein by genome editing attenuated the tumorigenic potential of p53-deficient OS cells. Taken together, these results show a rationale that GGCT is widely upregulated in cancer cells and solidify its suitability as a target for anticancer drugs.

Research progress and application of single-cell sequencing in head and neck malignant tumors

Single-cell sequencing (SCS) is a technology that separates thousands of cells from the organism and accurately analyzes the genetic material expressed in each cell using high-throughput sequencing technology. Unlike the traditional bulk sequencing approach, which can only provide the average value of a cell population and cannot obtain specific single-cell data, single-cell sequencing can identify the gene sequence and expression changes of a single cell, and reflects the differences between genetic material and protein between cells, and ultimately the role played by the tumor microenvironment. single-cell sequencing can further explore the pathogenesis of head and neck malignancies from the single-cell biological level and provides a theoretical basis for the clinical diagnosis and treatment of head and neck malignancies. This article will systematically introduce the latest progress and application of single-cell sequencing in malignant head and neck tumors.

C/ebpα represses the oncogenic Runx3-Myc axis in p53-deficient osteosarcoma development

Osteosarcoma (OS) is characterized by TP53 mutations in humans. In mice, loss of p53 triggers OS development, and osteoprogenitor-specific p53-deleted mice are widely used to study the process of osteosarcomagenesis. However, the molecular mechanisms underlying the initiation or progression of OS following or parallel to p53 inactivation remain largely unknown. Here, we examined the role of transcription factors involved in adipogenesis (adipo-TFs) in p53-deficient OS and identified a novel tumor suppressive molecular mechanism mediated by C/ebpα. C/ebpα specifically interacts with Runx3, a p53 deficiency-dependent oncogene, and, in the same manner as p53, decreases the activity of the oncogenic axis of OS, Runx3-Myc, by inhibiting Runx3 DNA binding. The identification of a novel molecular role for C/ebpα in p53-deficient osteosarcomagenesis underscores the importance of the Runx-Myc oncogenic axis as a therapeutic target for OS.

Protein-protein interactions between RUNX3 and ZEB1 in chronic lung injury induced by methamphetamine abuse

Methamphetamine (MA) is the most common and highly addictive substance abuse drug. Runt-related transcription factor 3 (RUNX3) and Zinc finger E-box-binding homeobox 1 (ZEB1) are associated with lung inflammation and fibrosis. However, the protein-protein interactions (PPIs) between RUNX3 and ZEB1 and its involvement in MA-induced chronic lung injury is still unclear. In this study, we evaluated lung injury using echocardiography, hematoxylin and eosin staining, and western blot analysis. The viability of alveolar epithelial cells (AECs) was assessed using cell counting kit-8. Molecular Operating Environment software, Search Tool for the Retrieval of Interacting Genes/Proteins database, co-immunoprecipitation, assay and confocal immunofluorescence assay were used to predict and identify the PPIs between RUNX3 and ZEB1. The expression of RUNX3 and ZEB1 were knockdown in AECs using siRNA. The results revealed that MA exposure increased the peak blood flow velocity of the pulmonary artery and the acceleration time of pulmonary artery blood flow. Further, exposure to MA also causes adhesion and fusion of the alveolar walls and altered AEC activity. A decrease in the expression of RUNX3 and an increase in the expression of ZEB1 and its downstream signaling molecules were observed on MA exposure. The PPIs between RUNX3 and ZEB1 were identified. Further, an increase in the protein binding rate of RUNX3-ZEB1 was observed in MA-induced lung injury. These results show interactions between RUNX3 and ZEB1. RUNX3 protects against lung injury; however, ZEB1 expression and the PPIs between ZEB1 and RUNX3 has deleterious effects on chronic lung injury induced by MA exposure. Our results provide a new therapeutic approach for the treatment of chronic lung injury due to MA exposure.

Circular RNAs: Emerging players in the pathogenesis of keloid

Circular RNAs (circRNAs) are a new type of non-coding RNAs originating from precursor messenger RNAs. Recent research has confirmed that circRNAs play a significant role in various biological and pathological processes, including cell viability, migration, and apoptosis. Emerging studies have demonstrated that the deregulated circRNA-miRNA-mRNA interaction network plays a key role in the development of many diseases. Increasing evidence has highlighted the role of ncRNAs (mainly miRNAs and lncRNAs) in the pathogenesis of keloids. Recently, several publications also indicated that circRNAs contribute to keloid development. The discovery of circRNAs changed the current understanding of the biology of keloids It is crucial to elucidate a circRNA-miRNA-mRNA network to understand the pathological mechanism of keloids. In the present review, we summarize the aberrant expression of regulatory roles of circRNAs in keloids. We discuss the potential clinical application of circRNAs in the diagnosis and treatment of keloids.

EZH2 regulates a SETDB1/ΔNp63α axis via RUNX3 to drive a cancer stem cell phenotype in squamous cell carcinoma

Enhancer of zeste homolog 2 (EZH2) and SET domain bifurcated 1 (SETDB1, also known as ESET) are oncogenic methyltransferases implicated in a number of human cancers. These enzymes typically function as epigenetic repressors of target genes by methylating histone H3 K27 and H3-K9 residues, respectively. Here, we show that EZH2 and SETDB1 are essential to proliferation in 3 SCC cell lines, HSC-5, FaDu, and Cal33. Additionally, we find both of these proteins highly expressed in an aggressive stem-like SCC sub-population. Depletion of either EZH2 or SETDB1 disrupts these stem-like cells and their associated phenotypes of spheroid formation, invasion, and tumor growth. We show that SETDB1 regulates this SCC stem cell phenotype through cooperation with ΔNp63α, an oncogenic isoform of the p53-related transcription factor p63. Furthermore, EZH2 is upstream of both SETDB1 and ΔNp63α, activating these targets via repression of the tumor suppressor RUNX3. We show that targeting this pathway with inhibitors of EZH2 results in activation of RUNX3 and repression of both SETDB1 and ΔNp63α, antagonizing the SCC cancer stem cell phenotype. This work highlights a novel pathway that drives an aggressive cancer stem cell phenotype and demonstrates a means of pharmacological intervention.

RUNX3/H3K27me3 Co-Expression Defines a Better Prognosis in Surgically Resected Stage I and Postoperative Chemotherapy-Naive Non-Small-Cell Lung Cancer

The purpose of this study is to investigate the significance of RUNX3/H3K27me3 co-expression in surgically resected non-small-cell lung cancer (NSCLC) patients. Using tissue microarray (TMA), immunohistochemistry, fluorescent double immunostaining, and western blotting, 208 NSCLC and 5 benign pulmonary patients were studied of their expression of runt-related transcription factor 3 (RUNX3), trimethylated histone H3 at lysine 27 (H3K27me3), enhancer of zeste homolog 2 (EZH2), and Ki-67. Apoptotic index in cancerous tissue was evaluated via TdT-mediated dUTP-biotin nick end labeling (TUNEL). The correlation between clinicopathologic parameters and overall survival was determined by Cox regression and Kaplan–Meier survival estimates and log-rank test. GEPIA and KM plotter were used for validation of some survival analyses. As a result, together with other regular prognostic factors, RUNX3/H3K27me3 co-expression was found to be closely correlated with better prognosis in either pTNM-I or POCT-naive NSCLC patients, which might partially result from a higher cancerous apoptotic index. In conclusion, RUNX3/H3K27me3 co-expression defined some specific NSCLC population with better prognosis and longer OS and could probably be used as a biomarker in the prediction of better postoperative outcomes.

Runx3 is required for oncogenic Myc upregulation in p53-deficient osteosarcoma

Osteosarcoma (OS) in human patients is characterized by genetic alteration of TP53. Osteoprogenitor-specific p53-deleted mice (OS mice) have been widely used to study the process of osteosarcomagenesis. However, the molecular mechanisms responsible for the development of OS upon p53 inactivation remain largely unknown. In this study, we detected prominent RUNX3/Runx3 expression in human and mouse p53-deficient OS. Myc was aberrantly upregulated by Runx3 via mR1, a consensus Runx site in the Myc promoter, in a manner dependent on p53 deficiency. Reduction of the Myc level by disruption of mR1 or Runx3 knockdown decreased the tumorigenicity of p53-deficient OS cells and effectively suppressed OS development in OS mice. Furthermore, Runx inhibitors exerted therapeutic effects on OS mice. Together, these results show that p53 deficiency promotes osteosarcomagenesis in human and mouse by allowing Runx3 to induce oncogenic Myc expression.

RUNX3 is up-regulated in abdominal aortic aneurysm and regulates the function of vascular smooth muscle cells by regulating TGF-β1

Abdominal aortic aneurysm (AAA) has been associated with the dysfunction of vascular smooth muscle cells (VSMCs) and extracellular matrix (ECM) remodelling. Runt-related transcription factor 3 (RUNX3) has been reported to be up-regulated in aneurysmal aorta samples compared with normal aorta. However, its function in VSMCs and the mechanism of function remains unknown. Therefore, our study aimed to investigate the role of RUNX3 in ECM remodelling and VSMC function, and further explore the underlying mechanism. Our results verified that RUNX3 was increased in aortic samples of AAA compared with healthy controls. Overexpression vectors of RUNX3 (ov-RUNX3) and siRNA of RUNX3 (si-RUNX3) were transfected into Human aortic smooth muscle cells (HAoSMCs). The results indicated that ov-RUNX3 promoted cell proliferation, migration, and MMP-2/3/9 secretion, and suppressed TIMP-1, collagen I/III, SM22, MYH11 and CNN1 expression in HAoSMCs. The silencing of RUNX3 has the opposite effect. Furthermore, we found that RUNX3 targets TGF-β1 and suppressed its transcription. The silencing of TGF-β1 increased cell proliferation, migration and MMP-2/3/9 expression, and inhibited TIMP-1, Collagen I/III, SM22, MYH11 and CNN1 expression. In addition, TGF-β1 reversed the effect of RUNX3 overexpression on HAoSMCs. Hence, our study indicated that RUNX3 promotes cell proliferation, migration, and ECM remodelling through suppressing TGF-β1.

Apoptosis and Cell Proliferation Markers in Inflammatory-Fibroproliferative Diseases of the Vessel Wall (Review)

Apoptosis is the main feature of inflammatory-fibroproliferative disorders of the vessel wall. Studies in animal models have shown that smooth muscle cells (SMCs) cultured from endarterectomy specimens from the affected area proliferate more slowly and display higher apoptotic indices than SMCs derived from the normal vessel wall. Apoptotic cells were found in the destabilized atherosclerotic plaques, as well as in the samples with restenosis of the reconstruction area.

Injury to the vessel wall causes two waves of apoptosis. The first wave is the rapid apoptosis in the media that occurs within a few hours after injury and leads to a marked reduction in the number of vascular wall cells. The second wave of apoptosis occurs much later (from several days to weeks) and is limited by the SMCs within the developing neointima. Up to 14% of the neointimal SMCs undergo apoptosis 20 days after balloon angioplasty. Ligation of the external carotid artery in a rabbit model led to a marked decrease in blood flow in the common carotid artery, which correlated with the increased apoptosis of endothelial cells and SMCs.

Angioplasty-induced death of SMCs is regulated by a redox-sensitive signaling pathway, and topical administration of antioxidants can minimize vascular cell loss. On the whole, studies show that apoptosis is prevalent in vascular lesions, controlling the viability of both inflammatory and vascular cells, determining the cellular composition of the vessel wall. The main markers of apoptosis (Fas, Fas ligand, p53, Bcl-2, Bax) and cell proliferation (toll receptor) have been considered in the current review.

Runt-Related Transcription Factor 3 Promotes Acute Myeloid Leukemia Progression

Acute myeloid leukemia (AML) is an aggressive hematological malignancy with high relapse/refractory rate. Genetic and epigenetic abnormalities are driving factors for leukemogenesis. RUNX1 and RUNX2 from the Runt-related transcription factor (RUNX) family played important roles in AML pathogenesis. However, the relationship between RUNX3 and AML remains unclear. Here, we found that RUNX3 was a super-enhancer-associated gene and highly expressed in AML cells. The Cancer Genome Atlas (TCGA) database showed high expression of RUNX3 correlated with poor prognosis of AML patients. We observed that Runx3 knockdown significantly inhibited leukemia progression by inducing DNA damage to enhance apoptosis in murine AML cells. By chromatin immunoprecipitation sequencing (ChIP-seq) analysis, we discovered that RUNX3 in AML cells mainly bound more genes involved in DNA-damage repair and antiapoptosis pathways compared to that in normal bone marrow cells. Runx3 knockdown obviously inhibited the expression of these genes in AML cells. Overall, we identified RUNX3 as an oncogene overexpressed in AML cells, and Runx3 knockdown suppressed AML progression by inducing DNA damage and apoptosis.

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.

Small peptide inhibitor from the sequence of RUNX3 disrupts PAK1-RUNX3 interaction and abrogates its phosphorylation-dependent oncogenic function

P21 Activated Kinase 1 (PAK1) is an oncogenic serine/threonine kinase known to play a significant role in the regulation of cytoskeleton and cell morphology. Runt-related transcription factor 3 (RUNX3) was initially known for its tumor suppressor function, but recent studies have reported the oncogenic role of RUNX3 in various cancers. Previous findings from our laboratory provided evidence that Threonine 209 phosphorylation of RUNX3 acts as a molecular switch in dictating the tissue-specific dualistic functions of RUNX3 for the first time. Based on these proofs and to explore the translational significance of these findings, we designed a small peptide (RMR) from the protein sequence of RUNX3 flanking the Threonine 209 phosphorylation site. The selection of this specific peptide from multiple possible peptides was based on their binding energies, hydrogen bonding, docking efficiency with the active site of PAK1 and their ability to displace PAK1-RUNX3 interaction in our prediction models. We found that this peptide is stable both in in vitro and in vivo conditions, not toxic to normal cells and inhibits the Threonine 209 phosphorylation in RUNX3 by PAK1. We also tested the efficacy of this peptide to block the RUNX3 Threonine 209 phosphorylation mediated tumorigenic functions in in vitro cell culture models, patient-derived explant (PDE) models and in in vivo tumor xenograft models. These results proved that this peptide has the potential to be developed as an efficient therapeutic molecule for targeting RUNX3 Threonine 209 phosphorylation-dependent tumor phenotypes.

Runx3 Induces a Cell Shape Change and Suppresses Migration and Metastasis of Melanoma Cells by Altering a Transcriptional Profile

Runt-related transcription factor-3 (Runx3) is a tumor suppressor, and its contribution to melanoma progression remains unclear. We previously demonstrated that Runx3 re-expression in B16-F10 melanoma cells changed their shape and attenuated their migration. In this study, we found that Runx3 re-expression in B16-F10 cells also suppressed their pulmonary metastasis. We performed microarray analysis and uncovered an altered transcriptional profile underlying the cell shape change and the suppression of migration and metastasis. This altered transcriptional profile was rich in Gene Ontology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) annotations relevant to adhesion and the actin cytoskeleton and included differentially expressed genes for some major extracellular matrix (ECM) proteins as well as genes that were inversely associated with the increase in the metastatic potential of B16-F10 cells compared to B16-F0 melanoma cells. Further, we found that this altered transcriptional profile could have prognostic value, as evidenced by myelin and lymphocyte protein (MAL) and vilin-like (VILL). Finally, Mal gene expression was correlated with metastatic potential among the cells and was targeted by histone deacetylase (HDAC) inhibitors in B16-F10 cells, and the knockdown of Mal gene expression in B16-F0 cells changed their shape and enhanced the migratory and invasive traits of their metastasis. Our study suggests that self-entrapping of metastatic Runx3-negative melanoma cells via adhesion and the actin cytoskeleton could be a powerful therapeutic strategy.

Circ_0008450 downregulates Runx3 to promote the proliferation and epithelial-mesenchymal transition of human keratinized epithelial cells

Keloid is an extremely common and often overlooked benign neoplastic disease, but its consequences should not be underestimated. Therefore, a deep exploration of the pathological mechanism of keloid becomes very essential. After 22 samples were collected from each patient's keloid tissues and normal skin tissues, circ_0008450 and Runx3 expression was tested by qRT-PCR. When primary human keratinized epithelial cells were transfected by sh-circ_0008450 or sh-Runx3, cell proliferation, apoptosis, migration, and EMT process were assessed by CCK-8, BrdU assay, apoptosis assay, migration assay, and Western blot. Finally, transfection was performed to explore the effect of circ_0008450 on the TGF-β/Smad signal pathway by adopting western blot. Circ_0008450 was highly expressed in keratinized epithelial tissues. After the transfection of sh-circ_0008450 into primary human keratinized epithelial cells, cell proliferation, migration, and EMT process were inhibited, and apoptosis was stimulated. Moreover, circ_0008450 silence-induced above changes were partly reversed by transfecting sh-Runx3. In addition, transfecting sh-circ_0008450 could repress TGF-β/Smad pathway, while transfecting sh-Runx3 activated the above pathway. Circ_0008450 down-regulated Runx3 to promote the proliferation and EMT process of human keratinized epithelial cells. This discovery may be related to the activation of the TGF-β/Smad pathway.

Elevated expression of RUNX3 co-expressing with EZH2 in esophageal cancer patients from India

Background

Runt related transcription factor3 (RUNX3) is considered as a tumor suppressor gene (TSG) that functions through the TGF-β dependent apoptosis. Promoter methylation of the CpG islands of RUNX3 and overexpression of enhancer of zeste homolog 2 (EZH2) has been suggested to downregulate RUNX3 in cancer.

Methods

Here, we studied the expression of RUNX3 and EZH2 in 58 esophageal tumors along with paired adjacent normal tissue. mRNA levels, protein expressions and cellular localizations of EZH2 and RUNX3 were analyzed using real-time PCR and immunohistochemistry, respectively. DNA methylation was further assessed by the methylation specific-PCR.

Results

Compared to normal tissue, a significant increase in expression of RUNX3 mRNA in 31/57 patient’s tumor tissue (p < 0.04) was observed. The expression of EZH2 was found to be upregulated compared to normal, and a significant positive correlation between EZH2 and RUNX3 expression was observed (p = 0.002). 22 of the 27 unmethylated cases at the promoter region of the RUNX3 had elevated RUNX3 protein expression (p < 0.001).

Conclusion

The data presented in this study provide new insights into the biology of RUNX3 and highlights the need to revisit our current understanding of the role of RUNX3 in cancer.

The Role of Nuclear Receptor Subfamily 1 Group H Member 4 (NR1H4) in Colon Cancer Cell Survival through the Regulation of c-Myc Stability

Nuclear receptor subfamily group H member 4 (NR1H4), also known as farnesoid X receptor, has been implicated in several cellular processes in the liver and intestine. Preclinical and clinical studies have suggested a role of NR1H4 in colon cancer development; however, how NR1H4 regulates colon cancer cell growth and survival remains unclear. We generated NR1H4 knockout (KO) colon cancer cells using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein-9 nuclease (CAS9) technology and explored the effects of NR1H4 KO in colon cancer cell proliferation, survival, and apoptosis. Interestingly, NR1H4 KO cells showed impaired cell proliferation, reduced colony formation, and increased apoptotic cell death compared to control colon cancer cells. We identified MYC as an important mediator of the signaling pathway alterations induced by NR1H4 KO. NR1H4 silencing in colon cancer cells resulted in reduced MYC protein levels, while NR1H4 activation using an NR1H4 ligand, chenodeoxycholic acid, resulted in time- and dose-dependent MYC induction. Moreover, NR1H4 KO enhanced the anti-cancer effects of doxorubicin and cisplatin, supporting the role of MYC in the enhanced apoptosis observed in NR1H4 KO cells. Taken together, our findings suggest that modulating NR1H4 activity in colon cancer cells might be a promising alternative approach to treat cancer using MYC-targeting agents.