Clinical significance of RUNX2 expression in patients with nonsmall cell lung cancer: a 5-year follow-up study

Chb-M', an Inhibitor of the RUNX Family Binding to DNA, Induces Apoptosis in p53-Mutated Non-Small Cell Lung Cancer and Inhibits Tumor Growth and Repopulation In Vivo

Runt-related transcription factor (RUNX) proteins are considered to play various roles in cancer. Here, we evaluated the anticancer activity of Chb-M', a compound that specifically and covalently binds to the consensus sequence for RUNX family proteins, in p53-mutated non-small cell lung cancer cells. Chb-M' killed the cancer cells by inducing apoptosis. The compound showed an anticancer effect comparable to that of the clinically used drugs alectinib and ceritinib in vivo. Notably, Chb-M' extended the cancer-free survival of mice after ending treatment more effectively than did the other two drugs. The results presented here suggest that Chb-M' is an attractive candidate as an anticancer drug applicable to the treatment of non-small cell lung cancer and various other types of cancers.

Roles of NOLC1 in cancers and viral infection

BACKGROUND

The nucleolus is considered the center of metabolic control and an important organelle for the biogenesis of ribosomal RNA (rRNA). Nucleolar and coiled-body phosphoprotein 1(NOLC1), which was originally identified as a nuclear localization signal-binding protein is a nucleolar protein responsible for nucleolus construction and rRNA synthesis, as well as chaperone shuttling between the nucleolus and cytoplasm. NOLC1 plays an important role in a variety of cellular life activities, including ribosome biosynthesis, DNA replication, transcription regulation, RNA processing, cell cycle regulation, apoptosis, and cell regeneration.

PURPOSE

In this review, we introduce the structure and function of NOLC1. Then we elaborate its upstream post-translational modification and downstream regulation. Meanwhile, we describe its role in cancer development and viral infection which provide a direction for future clinical applications.

METHODS

The relevant literatures from PubMed have been reviewed for this article.

CONCLUSION

NOLC1 plays an important role in the progression of multiple cancers and viral infection. In-depth study of NOLC1 provides a new perspective for accurate diagnosis of patients and selection of therapeutic targets.

Cigarette smoke induces epithelial-to-mesenchymal transition, stemness, and metastasis in lung adenocarcinoma cells via upregulated RUNX-2/galectin-3 pathway

AIMS

An elevated level of galectin-3, a carbohydrate-binding lectin implicated in tumorigenesis, metastasis, and epithelial-mesenchymal transition (EMT), has been found in cigarette smokers. However, the regulation of its expression and role in the pathogenesis of CS-induced EMT and lung cancer metastasis is unclear. Here, we have investigated the mechanism of CS-induced and galectin-3-mediated EMT in airway epithelial cells (AECs).

MAIN METHODS

A549 adenocarcinoma cells and primary small airway epithelial cells cultured on an air-liquid interface (ALI) were exposed to cigarette smoke extract (CSE), and MTT, trypan blue, migration, invasion, tumor spheroid and colony formation assays were performed to assess EMT phenotype. Immunoblotting was performed to assess EMT and stemness markers and other regulatory proteins.

KEY FINDINGS

CSE exposure affected cell survival and morphology, migration, invasion, and clonogenicity of AECs, which were concomitant with an increase in the expression of EMT markers, galectin-3, and runt-related transcription factor-2 (RUNX-2), an osteogenic transcription factor and upstream regulator of galectin-3. Chemical inhibition or silencing of RUNX-2 downregulated galectin-3 and modulated EMT marker expression, migration, invasion, and clonogenicity in CSE-exposed AECs. Recombinant human galectin-3 also induced EMT and stemness-associated changes in the AECs, and GB1107, a galectin-3 inhibitor, ameliorated these changes. Further, CSE-induced intracellular ROS enabled an increase in RUNX-2 and galectin-3 expression, which were reversed by n-acetyl-cysteine.

SIGNIFICANCE

These results provide a novel mechanistic insight into CSE-induced EMT via RUNX-2/galectin-3 axis mediated through ROS, which promoted EMT-associated changes, including invasion, migration, and stemness in AECs, which could be implicated in CS-induced lung cancer progression.

RUNX2 promotes the suppression of osteoblast function and enhancement of osteoclast activity by multiple myeloma cells

RUNX2 is a transcription factor that participates in osteoblast differentiation and chondrocyte maturation and plays an important role in the invasion and metastasis of cancers. With the deepening of research, evidence has indicated the correlation between RUNX2 and bone destruction in cancers. However, the mechanisms underlying its role in multiple myeloma remain unclear. By observing the induction effects of conditioned medium from myeloma cells on preosteoblasts (MC3T3-E1) and preosteoclasts (RAW264.7) and constructing myeloma-bearing mice, we found that RUNX2 promotes bone destruction in multiple myeloma. In vitro, conditioned medium from RUNX2-overexpressing myeloma cells reduced osteoblast activity and increased osteoclast activity. In vivo, RUNX2 expression was positively correlated with bone loss in myeloma-bearing mice. These results suggest that therapeutic inhibition of RUNX2 may protect against bone destruction by maintaining the balance between osteoblast and osteoclast activity in multiple myeloma.

Identification of the Transcriptional Regulatory Role of RUNX2 by Network Analysis in Lung Cancer Cells

The use of a new bioinformatics pipeline allowed the identification of deregulated transcription factors (TFs) coexpressed in lung cancer that could become biomarkers of tumor establishment and progression. A gene regulatory network (GRN) of lung cancer was created with the normalized gene expression levels of differentially expressed genes (DEGs) from the microarray dataset GSE19804. Moreover, coregulatory and transcriptional regulatory network (TRN) analyses were performed for the main regulators identified in the GRN analysis. The gene targets and binding motifs of all potentially implicated regulators were identified in the TRN and with multiple alignments of the TFs' target gene sequences. Six transcription factors (E2F3, FHL2, ETS1, KAT6B, TWIST1, and RUNX2) were identified in the GRN as essential regulators of gene expression in non-small-cell lung cancer (NSCLC) and related to the lung tumoral process. Our findings indicate that RUNX2 could be an important regulator of the lung cancer GRN through the formation of coregulatory complexes with other TFs related to the establishment and progression of lung cancer. Therefore, RUNX2 could become an essential biomarker for developing diagnostic tools and specific treatments against tumoral diseases in the lung after the experimental validation of its regulatory function.

Novel lncRNA LINC01614 Facilitates Bladder Cancer Proliferation, Migration and Invasion Through the miR-217/RUNX2/Wnt/β-Catenin Axis

Background

LncRNA plays a vital role in tumorigenesis and development. This study aimed to explore the novel lncRNA affecting bladder cancer progression.

Methods

The open-access data of bladder cancer patients, including transcriptome profiles and corresponding clinical information were all obtained from The Cancer Genome Atlas database. All the statistical analysis were performed using R software, SPSS and GraphPad Prism 8. CCK8, colony formation, apoptosis detection and tumorigenicity assay were used to assess cell proliferation ability. Transwell assay and wound-healing assay were used to evaluate cell metastasis potential.

Results

Our result showed that the lncRNA LINC01614 was highly expressed in bladder cancer tissue and cell lines. Meanwhile, patients with high LINC01614 expression level tend to have poor clinical features and shorter survival time. Further experiments demonstrated that the inhibition of LINC01614 could significantly hamper the proliferation and invasion of bladder cancer cells. Then, we found that the LINC01614 could regulate RUNX2 expression through miR-137. GSEA analysis indicated that the Wnt/β-catenin signaling pathway might be the downstream pathway of LINC01614. Further experiments showed that the LINC01614 act as an oncogene in bladder cancer partly depending on the RUNX2/Wnt/β-catenin axis, making it an underlying therapeutic target.

Conclusion

In all, LINC01614 facilitates bladder cancer cells proliferation, migration and invasion through the miR-217/RUNX2/Wnt/β-catenin axis.

RUNX2 and LAMC2: promising pancreatic cancer biomarkers identified by an integrative data mining of pancreatic adenocarcinoma tissues

Pancreatic carcinoma (PC) is a severe disease associated with high mortality. Although strategies for cancer therapy have made great progress, outcomes of pancreatic carcinoma patients remain extremely poor. Therefore, it is urgent to find novel biomarkers and therapeutic targets. To identify biomarkers for early diagnosis and therapy, three mRNA microarray datasets and two miRNA datasets were selected, and combinative analysis was performed by GEO2R. Functional and pathway enrichment analysis were performed using DAVID database. MiRTarBase, miRWalk and Diana Tools were used to get key genes. TCGA, HPA and western blotting were used to verify diagnostic and prognostic value of key genes. By integrating mRNA and miRNA expression profiles, we identified 114 differentially expressed genes and 114 differentially expressed miRNAs, respectively. Then, three overlapping key genes, RUNX2, LAMC2 and FBXO32, were found. Their protein levels in pancreatic tissue from PC patients and normal people were analyzed by immunohistochemical staining and western blotting. RUNX2 showed a potential property to identify PC. Aberrant over-expression of LAMC2 was associated with poor prognosis of PC patients, tumor status and subtypes. In summary, our current study identified that RUNX2 and LAMC2 may be promising targets for early diagnosis and therapy of PC patients.

RUNX2/miR‑31/SATB2 pathway in nickel‑induced BEAS‑2B cell transformation

Nickel (Ni) compounds are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) and are known to be carcinogenic to the lungs. In our previous study, special AT‑rich sequence‑binding protein 2 (SATB2) was required for Ni‑induced BEAS‑2B cell transformation. In the present study, a pathway that regulates the expression of SATB2 protein was investigated in Ni‑transformed BEAS‑2B cells using western blotting and RT‑qPCR for expression, and soft agar, migration and invasion assays for cell transformation. Runt‑related transcription factor 2 (RUNX2), a master regulator of osteogenesis and an oncogene, was identified as an upstream regulator for SATB2. Ni induced RUNX2 expression and initiated BEAS‑2B transformation and metastatic potential. Previously, miRNA‑31 was identified as a negative regulator of SATB2 during arsenic‑induced cell transformation, and in the present study it was identified as a downstream target of RUNX2 during carcinogenesis. miR‑31 expression was reduced in Ni‑transformed BEAS‑2B cells, which was required to maintain cancer hallmarks. The expression level of miR‑31 was suppressed by RUNX2 in BEAS‑2B cells, and this increased the expression level of SATB2, initiating cell transformation. Ni caused the repression of miR‑31 by placing repressive marks at its promoter, which in turn increased the expression level of SATB2, leading to cell transformation.

Wrong place, wrong time: Runt-related transcription factor 2/SATB2 pathway in bone development and carcinogenesis

Upregulation or aberrant expression of genes such as special AT-rich sequence-binding protein 2 (SATB2) is necessary for normal cell differentiation and tissue development and is often associated with carcinogenesis and metastatic progression. SATB2 is a critical transcription factor for biological development of various specialized cell lineages, such as osteoblasts and neurons. The dysregulation of SATB2 expression has recently been associated with various types of cancer, while the mechanisms and pathways by which it mediates tumorigenesis are not well elucidated. Runt-related transcription factor 2 (RUNX2) is a master regulator for osteogenesis, and it shares common pathways with SATB2 to regulate bone development. Interestingly, these two transcription factors co-occur in several epithelial and mesenchymal cancers and are linked by multiple cancer-related proteins and microRNAs. This review examines the interactions between RUNX2 and SATB2 in a network necessary for normal bone development and the circumstances in which the expression of RUNX2 and SATB2 in the wrong place and time leads to carcinogenesis.

A Zic2/Runx2/NOLC1 signaling axis mediates tumor growth and metastasis in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignancies with rapid growth and high metastasis, but lacks effective therapeutic targets. Here, using public sequencing data analyses, quantitative real-time PCR assay, western blotting, and IHC staining, we characterized that runt-related transcription factor 2 (Runx2) was significantly upregulated in ccRCC tissues than that in normal renal tissues, which was associated with the worse survival of ccRCC patients. Overexpression of Runx2 promoted malignant proliferation and migration of ccRCC cells, and inversely, interfering Runx2 with siRNA attenuates its oncogenic ability. RNA sequencing and functional studies revealed that Runx2 enhanced ccRCC cell growth and metastasis via downregulation of tumor suppressor nucleolar and coiled-body phosphoprotein 1 (NOLC1). Moreover, increased Zic family member 2 (Zic2) was responsible for the upregulation of Runx2 and its oncogenic functions in ccRCC. Kaplan-Meier survival analyses indicated that ccRCC patients with high Zic2/Runx2 and low NOLC1 had the worst outcome. Therefore, our study demonstrates that Zic2/Runx2/NOLC1 signaling axis promotes ccRCC progression, providing a set of potential targets and prognostic indicators for patients with ccRCC.

RUNX2 as a promising therapeutic target for malignant tumors

The transcription factor runt-related protein 2 (RUNX2) has an important impact on the transformation of bone marrow mesenchymal stem cells to osteoblasts. Further studies have shown that RUNX2 plays a key role in the invasion and metastasis of cancers. RUNX2 is a "key" molecule in the regulatory network comprised of multiple signaling pathways upstream and its target downstream molecules. Due to the complex regulatory mechanisms of RUNX2, the specific mechanism underlying the occurrence, development and prognosis of malignant tumors has not been fully understood. Currently, RUNX2 as a promising therapeutic target for cancers has become a research hotspot. Herein, we reviewed the current literature on the modulatory functions and mechanisms of RUNX2 in the development of malignant tumors, aiming to explore its potential clinical application in the diagnosis, prognosis and treatment of tumors.

CircRNA_102272 Promotes Cisplatin-Resistance in Hepatocellular Carcinoma by Decreasing MiR-326 Targeting of RUNX2

Background

Hepatocellular carcinoma (HCC) is the leading cause of tumor-associated death in males and females worldwide. HCC is mostly diagnosed at advanced stages and the chemotherapeutic cisplatin is one of the major therapeutic options in the treatment of patients with treating advanced HCC. Despite several reports on HCC multidrug resistance, the underlying regulatory mechanisms are still unclear.

Methods

RT-PCR was performed to detect circRNA_102272, miR-326 and RUNX2 expression. The CCK8 assay was used to examine cell proliferation and cisplatin IC₅₀ values. The luciferase reporter assay was performed to verify complementary combinations between circRNA_102272 and miR-326 and between miR-326 and RUNX2.

Results

CircRNA_102272 expression was upregulated in HCC tissues and cells. CircRNA_102272 knockdown suppressed HCC cell proliferation and decreased cisplatin-resistance. In addition, circRNA_102272 facilitated HCC cisplatin-resistance by regulating the miR-326/RUNX2 axis.

Conclusion

CircRNA_102272 is significantly increased in HCC tissues and cells and promotes HCC cell proliferation and cisplatin-resistance. More importantly, circRNA acts as a ceRNA to suppress the expression and activity of miR-326, leading to the increase in RUNX2 expression. By elucidating circRNA_102272 role and mechanism of action in HCC, our study provides insights and an opportunity to overcome cisplatin-resistance in HCC.

Clinical significance of transcription factor RUNX2 in lung adenocarcinoma and its latent transcriptional regulating mechanism

RUNX family transcription factor 2 (RUNX2) overexpression has been found in various human malignancies. However, the expression levels of RUNX2 mRNA and protein in lung adenocarcinoma (LUAD) were not investigated. This study aims to thoroughly analysis the expression level and potential mechanisms of RUNX2 mRNA in LUAD. We applied in-house immunohistochemistry, high-throughput RNA-sequencing, and gene microarrays to comprehensively investigate the expression level of RUNX2 in LUAD. A pool standard mean difference (SMD) and summary receiver operating characteristic curves (SROC) were calculated to assess the integrated expression value of RUNX2 in LUAD. The hazard ratios (HRs) were integrated to evaluate the overall prognostic effect of RUNX2 on the LUAD patients. The differentially expressed genes (DEGs) of LUAD, the potential target genes of RUNX2, and its co-expressed genes were overlapped to obtain a set of specific genes for GO and KEGG enrichment analyses. RUNX2 overexpression in LUAD was validated using a large number of cases (2 418 LUAD and 1 574 non-tumor lung samples). The pooled SMD was 0.85 (95 % CI: 0.64-1.05) and the area under the curve (AUC) of the SROC was 0.86 (95 %CI: 0.83-0.89). The integrated HR was 1.20 [1.04-1.38], indicating that increased expression of RUNX2 was an independent risk factor for the poor survival of the LUAD patients. RUNX2 and its transcriptionally regulates potential target genes may promote cell proliferation and drug resistance of LUAD by modulating the cell cycle and MAPK signaling pathways. RUNX2 can provide new research directions for targeted drug therapy and drug resistance for LUAD treatment.

Integrated expression analysis revealed RUNX2 upregulation in lung squamous cell carcinoma tissues

This study aimed to investigate the clinicopathological significance and prospective molecular mechanism of RUNX family transcription factor 2 (RUNX2) in lung squamous cell carcinoma (LUSC). The authors used immunohistochemistry (IHC), RNA-seq, and microarray data from multi-platforms to conduct a comprehensive analysis of the clinicopathological significance and molecular mechanism of RUNX2 in the occurrence and development of LUSC. RUNX2 expression was significantly higher in 16 LUSC tissues than in paired non-cancerous tissues detected by IHC (P < 0.05). RNA-seq data from the combination of TCGA and genotype-tissue expression (GTEx) revealed significantly higher expression of RUNX2 in 502 LUSC samples than in 476 non-cancer samples. The expression of RUNX2 protein was also significantly higher in pathologic T3-T4 than in T1-T2 samples (P = 0.031). The pooled standardised mean difference (SMD) for RUNX2 was 0.87 (95% CI, 0.58-1.16), including 29 microarrays from GEO and one from ArrayExpress. The co-expression network of RUNX2 revealed complicated connections between RUNX2 and 45 co-expressed genes, which were significantly clustered in pathways including ECM-receptor interaction, focal adhesion, protein digestion and absorption, human papillomavirus infection and PI3K-Akt signalling pathway. Overexpression of RUNX2 plays an essential role in the clinical progression of LUSC.

Epigenomic State Transitions Characterize Tumor Progression in Mouse Lung Adenocarcinoma

Regulatory networks that maintain functional, differentiated cell states are often dysregulated in tumor development. Here, we use single-cell epigenomics to profile chromatin state transitions in a mouse model of lung adenocarcinoma (LUAD). We identify an epigenomic continuum representing loss of cellular identity and progression toward a metastatic state. We define co-accessible regulatory programs and infer key activating and repressive chromatin regulators of these cell states. Among these co-accessibility programs, we identify a pre-metastatic transition, characterized by activation of RUNX transcription factors, which mediates extracellular matrix remodeling to promote metastasis and is predictive of survival across human LUAD patients. Together, these results demonstrate the power of single-cell epigenomics to identify regulatory programs to uncover mechanisms and key biomarkers of tumor progression.

Novel Melatonin, Estrogen, and Progesterone Hormone Therapy Demonstrates Anti-Cancer Actions in MCF-7 and MDA-MB-231 Breast Cancer Cells

A novel melatonin, estrogen, and progesterone hormone therapy was developed as a safe bio-identical alternative hormone therapy for menopausal women based on the Women’s Health Initiative findings that PremPro™ increased breast cancer risk and mortality of all types of breast cancer in postmenopausal women. For HER2 breast cancer, melatonin, estrogen, and progesterone delayed tumor onset and reduced tumor incidence in neu female mice. For other breast cancers, its actions are unknown. In this study, melatonin, estrogen, and progesterone hormone therapy were assessed in human ER+ (MCF-7) and triple negative breast cancer (MDA-MB-231) cells, and found to decrease proliferation and migration of both breast cancer lines. Inhibition of MEK1/2 and 5 using PD98059 and BIX02189, respectively, inhibited proliferation and migration in MDA-MB-231 cells and proliferation in MCF-7 cells; however, when combined with melatonin, estrogen, and progesterone, BIX02189 blocked melatonin, estrogen, and progesterone–mediated inhibition of migration in MCF-7 cells and induced Elf-5. For MDA-MB-231 cells, BIX02189 combined with melatonin, estrogen, and progesterone inhibited proliferation and increased pERK1/2 and β1-INTEGRIN; levels of pERK5 remained low/nearly absent in both breast cancer lines. These findings demonstrate novel anti-cancer actions of melatonin, estrogen, and progesterone in ER+ and triple negative breast cancer cells through intricate MEK1/2- and MEK5-associated signaling cascades that favor anti-proliferation and anti-migration.

The significance of Runx2 mediating alcohol-induced Brf1 expression and RNA Pol III gene transcription

Runx2 (Runt-related transcription factor 2) is a key transcription factor which is associated with osteoblast differentiation and expressed in ER+ (estrogen receptor positive) human breast cancer cell lines. Runx2 also participates in mammary gland development. Deregulation of RNA Pol III genes (polymerase III-dependent genes) is tightly linked to tumor development, while Brf1 (TFIIB-related factor 1) specifically regulates these gene transcription. However, nothing is known about the effect of Runx2 on Brf1 expression and Pol III gene transcription. Expression of Runx2, Brf1 and Pol III genes from the samples of human breast cancer and cell culture model were determined by the assays of RT-qPCR, immunoblot, luciferase reporter activity, immunohistochemistry, chromatin immunoprecipitation and Immunofluorescence. High expression of Runx2 is observed in the cases of breast cancer. The patients of high Runx2 expression at early stages display longer survival period, whereas the cases of high Runx2 at advanced stages reveal faster recurrence. The identification of signaling pathway indicates that JNK1 and c-Jun mediate Runx2 transcription. Repression of Runx2 reduces Brf1 expression and Pol III gene transcription. Further analysis indicates that Runx2 is colocalized with Brf1 in nucleus of breast cancer tissue. Both Runx2 and Brf1 synergistically modulate Pol III gene transcription. These studies indicate that Brf1 overexpression is able to be used as an early diagnosis biomarker of breast cancer, while high Runx2 expression indicates long survival period and faster recurrence. Runx2 mediates the deregulation of Brf1 and Pol III genes and its abnormal expression predicts the worse prognosis of breast cancer.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

HDACs control RUNX2 expression in cancer cells through redundant and cell context-dependent mechanisms

Background

RUNX2 is a Runt-related transcription factor required during embryogenesis for skeletal development and morphogenesis of other organs including thyroid and breast gland. Consistent evidence indicates that RUNX2 expression is aberrantly reactivated in cancer and supports tumor progression. The mechanisms leading to RUNX2 expression in cancer has only recently began to emerge. Previously, we showed that suppressing the activity of the epigenetic regulators HDACs significantly represses RUNX2 expression highlighting a role for these enzymes in RUNX2 reactivation in cancer. However, the molecular mechanisms by which HDACs control RUNX2 are still largely unexplored. Here, to fill this gap, we investigated the role of different HDACs in RUNX2 expression regulation in breast and thyroid cancer, tumors that majorly rely on RUNX2 for their development and progression.

Methods

Proliferation assays and evaluation of RUNX2 mRNA levels by qRT-PCR were used to evaluate the effect of several HDACi and specific siRNAs on a panel of cancer cell lines. Moreover, ChIP and co-IP assays were performed to elucidate the molecular mechanism underneath the RUNX2 transcriptional regulation. Finally, RNA-sequencing unveiled a new subset of genes whose transcription is regulated by the complex RUNX2-HDAC6.

Results

In this study, we showed that Class I HDACs and in particular HDAC1 are required for RUNX2 efficient transcription in cancer. Furthermore, we found an additional and cell-specific function of HDAC6 in driving RUNX2 expression in thyroid cancer cells. In this model, HDAC6 likely stabilizes the assembly of the transcriptional complex, which includes HDAC1, on the RUNX2 P2 promoter potentiating its transcription. Since a functional interplay between RUNX2 and HDAC6 has been suggested, we used RNA-Seq profiling to consolidate this evidence in thyroid cancer and to extend the knowledge on this cooperation in a setting in which HDAC6 also controls RUNX2 expression.

Conclusions

Overall, our data provide new insights into the molecular mechanisms controlling RUNX2 in cancer and consolidate the rationale for the use of HDACi as potential pharmacological strategy to counteract the pro-oncogenic program controlled by RUNX2 in cancer cells.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1350-5) contains supplementary material, which is available to authorized users.

Role of RUNX2 transcription factor in epithelial mesenchymal transition in non-small cell lung cancer: Epigenetic control of the RUNX2 P1 promoter

Lung cancer has a high mortality rate in men and women worldwide. Approximately 15% of diagnosed patients with this type of cancer do not exceed the 5-year survival rate. Unfortunately, diagnosis is established in advanced stages, where other tissues or organs can be affected. In recent years, lineage-specific transcription factors have been associated with a variety of cancers. One such transcription factor possibly regulating cancer is RUNX2, the master gene of early and late osteogenesis. In thyroid and prostate cancer, it has been reported that RUNX2 regulates expression of genes important in tumor cell migration and invasion. In this study, we report on RUNX2/ p57 overexpression in 16 patients with primary non-small cell lung cancer and/or metastatic lung cancer associated with H3K27Ac at P1 gene promoter region. In some patients, H3K4Me3 enrichment was also detected, in addition to WDR5, MLL2, MLL4, and UTX enzyme recruitment, members of the COMPASS-LIKE complex. Moreover, transforming growth factor-β induced RUNX2/ p57 overexpression and specific RUNX2 knockdown supported a role for RUNX2 in epithelial mesenchymal transition, which was demonstrated through loss of function assays in adenocarcinoma A549 lung cancer cell line. Furthermore, RUNX2 increased expression of epithelial mesenchymal transition genes VIMENTIN, TWIST1, and SNAIL1, which reflected increased migratory capacity in lung adenocarcinoma cells.

Loss of RUNX1 is associated with aggressive lung adenocarcinomas

The mammalian runt-related factor 1 (RUNX1) is a master transcription factor that regulates lineage specification of hematopoietic stem cells. RUNX1 translocations result in the development of myeloid leukemias. Recently, RUNX1 has been implicated as a tumor suppressor in other cancers. We postulated RUNX1 expression may be associated with lung adenocarcinoma etiology and/or progression. We evaluated the association of RUNX1 mRNA expression with overall survival data from The Cancer Genome Atlas (TCGA), a publically available database. Compared to high expression levels, Low RUNX1 levels from lung adenocarcinomas were associated with a worse overall survival (Hazard Ratio = 2.014 (1.042-3.730 95% confidence interval), log-rank p = 0.035) compared to those that expressed high RUNX1 levels. Further immunohistochemical examination of 85 surgical specimens resected at the University of Vermont Medical Center identified that low RUNX1 protein expression was associated with larger tumors (p = 0.038). Gene expression network analysis was performed on the same subset of TCGA cases that demonstrated differential survival by RUNX1 expression. This analysis, which reveals regulatory relationships, showed that reduced RUNX1 levels were closely linked to upregulation of the transcription factor E2F1. To interrogate this relationship, RUNX1 was depleted in a lung cancer cell line that expresses high levels of RUNX1. Loss of RUNX1 resulted in enhanced proliferation, migration, and invasion. RUNX1 depletion also resulted in increased mRNA expression of E2F1 and multiple E2F1 target genes. Our data implicate loss of RUNX1 as driver of lung adenocarcinoma aggression, potentially through deregulation of the E2F1 pathway.

Cell-specific expression of runt-related transcription factor 2 contributes to pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with limited therapeutic options and unknown etiology. IPF is characterized by epithelial cell injury, impaired cellular crosstalk between epithelial cells and fibroblasts, and the formation of fibroblast foci with increased extracellular matrix deposition (ECM). We investigated the role of runt-related transcription factor 2 (RUNX2), a master regulator of bone development that has been linked to profibrotic signaling. RUNX2 expression was up-regulated in lung homogenates from patients with IPF and in experimental bleomycin-induced lung fibrosis. The RUNX2 level correlated with disease severity as measured by decreased diffusing capacity and increased levels of the IPF biomarker, matrix metalloproteinase 7. Nuclear RUNX2 was observed in prosurfactant protein C-positive hyperplastic epithelial cells and was rarely found in myofibroblasts. We discovered an up-regulation of RUNX2 in fibrotic alveolar epithelial type II (ATII) cells as well as an increase of RUNX2-negative fibroblasts in experimental and human pulmonary fibrosis. Functionally, small interfering RNA-mediated RUNX2 knockdown decreased profibrotic ATII cell function, such as proliferation and migration, whereas fibroblasts displayed activation markers and increased ECM expression after RUNX2 knockdown. This study reveals that RUNX2 is differentially expressed in ATII cells vs. fibroblasts in lung fibrosis, which contributes to profibrotic cell function. Cell-specific targeting of RUNX2 pathways may represent a therapeutic approach for IPF.-Mümmler, C., Burgy, O., Hermann, S., Mutze, K., Günther, A., Königshoff, M. Cell-specific expression of runt-related transcription factor 2 contributes to pulmonary fibrosis.

RUNX2 expression in thyroid and breast cancer requires the cooperation of three non-redundant enhancers under the control of BRD4 and c-JUN

Aberrant reactivation of embryonic pathways is a common feature of cancer. RUNX2 is a transcription factor crucial during embryogenesis that is aberrantly reactivated in many tumors, including thyroid and breast cancer, where it promotes aggressiveness and metastatic spreading. Currently, the mechanisms driving RUNX2 expression in cancer are still largely unknown. Here we showed that RUNX2 transcription in thyroid and breast cancer requires the cooperation of three distantly located enhancers (ENHs) brought together by chromatin three-dimensional looping. We showed that BRD4 controls RUNX2 by binding to the newly identified ENHs and we demonstrated that the anti-proliferative effects of bromodomain inhibitors (BETi) is associated with RUNX2 transcriptional repression. We demonstrated that each RUNX2 ENH is potentially controlled by a distinct set of TFs and we identified c-JUN as the principal pivot of this regulatory platform. We also observed that accumulation of genetic mutations within these elements correlates with metastatic behavior in human thyroid tumors. Finally, we identified RAINs, a novel family of ENH-associated long non-coding RNAs, transcribed from the identified RUNX2 regulatory unit. Our data provide a new model to explain how RUNX2 expression is reactivated in thyroid and breast cancer and how cancer-driving signaling pathways converge on the regulation of this gene.

MicroRNA-218 inhibits proliferation and invasion in ovarian cancer by targeting Runx2

MicroRNA-218 (miR-218) has been implicated in the development and progression of multiple cancers. We investigated the role of miR-218 in ovarian cancer progression. We found that miR-218 expression levels were lower in ovarian cancer tissues and cell lines than in adjacent normal tissues or a normal ovarian cell line.miR-218 levels associated with International Federation of Gynecology and Obstetrics (FIGO) stage and lymph node metastasis. Exogenous expression of miR-218 inhibited cell proliferation, colony formation, migration, and invasion in vitro and suppressed tumor growth in a tumor-bearing nude mouse model. Runt-related transcription factor 2 (RUNX2) was identified as a direct functional target of miR-218, and its expression was inversely correlated with miR-218 expression in ovarian cancer tissues. RUNX2 overexpression rescued the suppressive effect of miR-218 on ovarian cancer cell proliferation, colony formation, migration, and invasion. These findings highlight an important role played bymiR-218 in the regulation of cancer growth and metastasis, in part by repressing RUNX2, and revealed the potential of miR-218 as a new therapeutic target inovarian cancer.

Association of genetic polymorphisms with survival of pancreatic ductal adenocarcinoma patients

Germline genetic variability might contribute, at least partially, to the survival of pancreatic ductal adenocarcinoma (PDAC) patients. Two recently performed genome-wide association studies (GWAS) on PDAC overall survival (OS) suggested (P < 10(-5)) the association between 30 genomic regions and PDAC OS. With the aim to highlight the true associations within these regions, we analyzed 44 single-nucleotide polymorphisms (SNPs) in the 30 candidate regions in 1722 PDAC patients within the PANcreatic Disease ReseArch (PANDoRA) consortium. We observed statistically significant associations for five of the selected regions. One association in the CTNNA2 gene on chromosome 2p12 [rs1567532, hazard ratio (HR) = 1.75, 95% confidence interval (CI) 1.19-2.58, P = 0.005 for homozygotes for the minor allele] and one in the last intron of the RUNX2 gene on chromosome 6p21 (rs12209785, HR = 0.88, 95% CI 0.80-0.98, P = 0.014 for heterozygotes) are of particular relevance. These loci do not coincide with those that showed the strongest associations in the previous GWAS. In silico analysis strongly suggested a possible mechanistic link between these two SNPs and pancreatic cancer survival. Functional studies are warranted to confirm the link between these genes (or other genes mapping in those regions) and PDAC prognosis in order to understand whether these variants may have the potential to impact treatment decisions and design of clinical trials.

Silencing of RUNX2 enhances gemcitabine sensitivity of p53-deficient human pancreatic cancer AsPC-1 cells through the stimulation of TAp63-mediated cell death

Runt-related transcription factor 2 (RUNX2) has been considered to be one of master regulators for osteoblast differentiation and bone formation. Recently, we have described that RUNX2 attenuates p53/TAp73-dependent cell death of human osteosarcoma U2OS cells bearing wild-type p53 in response to adriamycin. In this study, we have asked whether RUNX2 silencing could enhance gemcitabine (GEM) sensitivity of p53-deficient human pancreatic cancer AsPC-1 cells. Under our experimental conditions, GEM treatment increased the expression level of p53 family TAp63, whereas RUNX2 was reduced following GEM exposure, indicating that there exists an inverse relationship between the expression level of TAp63 and RUNX2 following GEM exposure. To assess whether TAp63 could be involved in the regulation of GEM sensitivity of AsPC-1 cells, small interfering RNA-mediated knockdown of TAp63 was performed. As expected, silencing of TAp63 significantly prohibited GEM-dependent cell death as compared with GEM-treated non-silencing cells. As TAp63 was negatively regulated by RUNX2, we sought to examine whether RUNX2 knockdown could enhance the sensitivity to GEM. Expression analysis demonstrated that depletion of RUNX2 apparently stimulates the expression of TAp63, as well as proteolytic cleavage of poly ADP ribose polymerase (PARP) after GEM exposure, and further augmented GEM-mediated induction of p53/TAp63-target genes, such as p21^WAF1, PUMA and NOXA, relative to GEM-treated control-transfected cells, implying that RUNX2 has a critical role in the regulation of GEM resistance through the downregulation of TAp63. Notably, ablation of TAp63 gave a decrease in number of γH2AX-positive cells in response to GEM relative to control-transfected cells following GEM exposure. Consistently, GEM-dependent phosphorylation of ataxia telangiectasia-mutated protein was remarkably impaired in TAp63 knockdown cells. Collectively, our present findings strongly suggest that RUNX2-mediated repression of TAp63 contributes at least in part to GEM resistance of AsPC-1 cells, and thus silencing of RUNX2 may be a novel strategy to enhance the efficacy of GEM in p53-deficient pancreatic cancer cells.

Myeloma cell-derived Runx2 promotes myeloma progression in bone

The progression of multiple myeloma (MM) is governed by a network of molecular signals, the majority of which remain to be identified. Recent studies suggest that Runt-related transcription factor 2 (Runx2), a well-known bone-specific transcription factor, is also expressed in solid tumors, where expression promotes both bone metastasis and osteolysis. However, the function of Runx2 in MM remains unknown. The current study demonstrated that (1) Runx2 expression in primary human MM cells is significantly greater than in plasma cells from healthy donors and patients with monoclonal gammopathy of undetermined significance; (2) high levels of Runx2 expression in MM cells are associated with a high-risk population of MM patients; and (3) overexpression of Runx2 in MM cells enhanced tumor growth and disease progression in vivo. Additional studies demonstrated that MM cell-derived Runx2 promotes tumor progression through a mechanism involving the upregulation of Akt/β-catenin/Survivin signaling and enhanced expression of multiple metastatic genes/proteins, as well as the induction of a bone-resident cell-like phenotype in MM cells. Thus, Runx2 expression supports the aggressive phenotype of MM and is correlated with poor prognosis. These data implicate Runx2 expression as a major regulator of MM progression in bone and myeloma bone disease.

miR‑338‑3p suppresses tumor growth of ovarian epithelial carcinoma by targeting Runx2

miR‑338‑3p, a recently discovered miRNA, has been shown to play important roles in tumorigenesis and metastasis in various cancers. However, the exact roles and mechanisms of miR‑338‑3p remain unknown in human ovarian epithelial carcinoma (EOC). The relationship between miR‑338‑3p expression pattern and clinicopathological features of patients with EOC were determined by real-time quantitative RT-PCR. Furthermore, the role of miR‑338‑3p and possible molecular mechanisms in EOC was investigated by several in vitro approaches and in a nude mouse model. We first showed that the expression of miR‑338‑3p was significantly downregulated in EOC tissues compared to those in adjacent normal tissues, and the value was negatively related to advanced FIGO stage, high histological grading and lymph node metastasis (P<0.01). An in vitro analysis revealed that the overexpression of miR‑338‑3p in EOC cells significantly inhibited cell proliferation, colony formation, migration and invasion, inducing cell apoptosis and enhancing caspase-3, -8, and -9 activities. Bioinformatic analysis and dual luciferase assays identified Runx2 as a direct target of miR‑338‑3p. We also found that enforced expression of miR‑338‑3p markedly inhibited the in vivo tumorigenicity in a nude mouse xenograft model system. Furthermore, overexpression of miR‑338‑3p inhibited phosphorylation of PI3K and AKT, which contributed to suppression of ovarian cancer cell growth. These findings revealed that miR‑338‑3p may act as a tumor suppressor that blocks the growth of human ovarian epithelial carcinoma through PI3K/AKT signaling pathways by targeting Runx2.

Histone Deacetylase Inhibitors Repress Tumoral Expression of the Proinvasive Factor RUNX2

Aberrant reactivation of embryonic pathways occurs commonly in cancer. The transcription factor RUNX2 plays a fundamental role during embryogenesis and is aberrantly reactivated during progression and metastasization of different types of human tumors. In this study, we attempted to dissect the molecular mechanisms governing RUNX2 expression and its aberrant reactivation. We identified a new regulatory enhancer element, located within the RUNX2 gene, which is responsible for the activation of the RUNX2 promoter and for the regulation of its expression in cancer cells. Furthermore, we have shown that treatment with the anticancer compounds histone deacetylase inhibitor (HDACi) results in a profound inhibition of RUNX2 expression, which is determined by the disruption of the transcription-activating complex on the identified enhancer. These data envisage a possible targeting strategy to counteract the oncongenic function of RUNX2 in cancer cells and provide evidence that the cytotoxic activity of HDACi in cancer is not only dependent on the reactivation of silenced oncosuppressors but also on the repression of oncogenic factors that are necessary for survival and progression.

Role of runt-related transcription factor 2 in signal network of tumors as an inter-mediator

Runt-related transcription factor 2 (RUNX2) is a member of the polyomavirus enhancer-binding protein 2/core-binding factor superfamily. RUNX2 is known for its contribution to osteoblast phenotype and bone formation. In recent years, increasing attention has been focused on the relationship of Runx2 with tumorigenesis. In different types of tumor cells, RUNX2 cooperates with its co-activators or co-inhibitors, and mediates the responses of cells to various signaling pathways that are hyperactive in tumors. Thus, several downstream target genes of RUNX2 are activated when RUNX2 interacts with its co-factors, leading to a variety of effects on tumor cells (epithelial-mesenchymal transition, metastasis, proliferation, and osteolytic lesion). This review focuses on the involvement of RUNX2 in tumor cells in the crosstalk of diverse signaling pathways and its multiple functions to develop optimal and feasible approaches for clinical treatment based on the functions of RUNX2.

Combined Runx2 and Snail overexpression is associated with a poor prognosis in breast cancer

The purpose of this study was to investigate the prognostic value of Runx2 and Snail expression in breast cancer. The expression of Runx2 and Snail in clinical specimens from 125 breast cancer patients was detected by immunohistochemistry. The results showed there is a link between Runx2 and Snail expression at protein levels (p = 0.007). The Kaplan-Meier survival analysis showed that Runx2 or Snail expression was correlated with shortened disease-free survival (DFS) (p = 0.002, p = 0.004, respectively) and overall survival (OS) (p = 0.002, p = 0.009, respectively). In addition, Runx2-positive/Snail-positive patients had the worst DFS and OS (p = 0.001, p < 0.001, respectively). In multivariate survival analysis, Runx2, Snail, and combined Runx2/Snail were still remained as independent prognostic factors for DFS (p = 0.020, p = 0.013, and p = 0.001, respectively) and OS (p = 0.027, p = 0.030 and p = 0.005, respectively). These results suggest that a combined Runx2/Snail expression could be used as a new significant prognostic biomarker for patients with breast cancer.

Altered Transcriptional Control Networks with Trans-Differentiation of Isogenic Mutant-KRas NSCLC Models

Background: The capacity of cancer cells to undergo epithelial mesenchymal trans-differentiation has been implicated as a factor driving metastasis, through the acquisition of enhanced migratory/invasive cell programs and the engagement of anti-apoptotic mechanisms promoting drug and radiation resistance. Our aim was to define molecular signaling changes associated with mesenchymal trans-differentiation in two KRas mutant NSCLC models. We focused on central transcription and epigenetic regulators predicted to be important for mesenchymal cell survival.

Experimental design: We have modeled trans-differentiation and cancer stemness in inducible isogenic mutant-KRas H358 and A549 non-small cell lung cell backgrounds. As expected, our models show mesenchymal-like tumor cells acquire novel mechanisms of cellular signaling not apparent in their epithelial counterparts. We employed large-scale quantitative phosphoproteomic, proteomic, protein–protein interaction, RNA-Seq, and network function prediction approaches to dissect the molecular events associated with the establishment and maintenance of the mesenchymal state.

Results: Gene-set enrichment and pathway prediction indicated BMI1, KDM5B, RUNX2, MYC/MAX, NFκB, LEF1, and HIF1 target networks were significantly enriched in the trans-differentiation of H358 and A549 NSCLC models. Physical overlaps between multiple networks implicate NR4A1 as an overlapping control between TCF and NFκB pathways. Enrichment correlations also indicated marked decrease in cell cycling, which occurred early in the EMT process. RNA abundance time course studies also indicated early expression of epigenetic and chromatin regulators within 8–24 h, including CITED4, RUNX3, CMBX1, and SIRT4.

Conclusion: Multiple transcription and epigenetic pathways where altered between epithelial and mesenchymal tumor cell states, notably the polycomb repressive complex-1, HP1γ, and BAF/Swi-Snf. Network analysis suggests redundancy in the activation and inhibition of pathway regulators, notably factors controlling epithelial cell state. Through large-scale transcriptional and epigenetic cell reprograming, mesenchymal trans-differentiation can promote diversification of signaling networks potentially important in resistance to cancer therapies.

The prognostic significance of RUNX2 and miR-10a/10b and their inter-relationship in breast cancer

Background

The major cancer related mortality is caused by metastasis and invasion. It is important to identify genes regulating metastasis and invasion in order to curtail metastatic spread of cancer cells.

Methods

This study investigated the association between RUNX2 and miR-10a/miR-10b and the risk of breast cancer relapse. Expression levels of RUNX2 and miR-10a/b in108 pairs of tumor and non-tumor tissue of breast cancer were assayed by quantitative PCR analysis and evaluated for their prognostic implications.

Results

The median expression levels of RUNX2 and miR-10b in tumor tissue normalized using adjacent non-tumor tissue were significantly higher in relapsed patients than in relapse-free patients. Higher expression of these three genes were significantly correlated with the hazard ratio for breast cancer recurrence (RUNX2: 3.02, 95% CI = 1.50 ~ 6.07; miR-10a: 2.31, 95% CI = 1.00 ~ 5.32; miR-10b: 3.96, 95% CI = 1.21 ~ 12.98). The joint effect of higher expression of all three genes was associated with a hazard ratio of 12.37 (95% CI = 1.62 ~ 94.55) for relapse. In a breast cancer cell line, RUNX2 silencing reduced the expression of miR-10a/b and also impaired cell motility, while RUNX2 overexpression elicited opposite effects.

Conclusions

These findings indicate that higher expression of RUNX2 and miR-10a/b was associated with adverse outcome of breast cancer. Expression levels of RUNX2 and miR-10a/b individually or jointly are potential prognostic factors for predicting breast cancer recurrence. Data from in vitro studies support the notion that RUNX2 promoted cell motility by upregulating miR-10a/b.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-014-0257-3) contains supplementary material, which is available to authorized users.

Tumor suppressor long non-coding RNA, MT1DP is negatively regulated by YAP and Runx2 to inhibit FoxA1 in liver cancer cells

Recent studies are indicative for strong carcinogenetic roles of Runt related transcription factor 2 (Runx2) and Yes associated protein (YAP) in several cancer types. However, whether and how the interaction between Runx2 and YAP plays a role in liver tumorigenesis still remain illusive. Here, we identified a close relationship between Runx2 and YAP in liver cancer cells. Runx2 had a positive role on YAP expression and vice versa. We also found that Rux2 and YAP were capable of inhibiting long non-coding RNA (lncRNA), Metallothionein 1D, Pseudogene (MT1DP) expression through direct promoter binding. Overexpression of MT1DP resulted in reduced cell proliferation and colony formation in soft agar, but increased apoptosis in liver cancer cells, whereas knockdown of this lncRNA had the opposite effect, indicating that MT1DP acts as a tumor suppressor. Furthermore, MT1DP was revealed as a negative regulator of Alfa-fetoprotein (AFP), a classic liver cancer tumor marker, through inhibiting protein synthesis of Forkhead box A1 (FoxA1), an important transcription factor in liver development and cancer progression. Furthermore, we found that FoxA1 plays a positive role on YAP and Runx2 expression. Specially, opening the compacted chromatin by FoxA1 around CREB binding site within the YAP promoter facilitates CREB-mediated YAP transcription. Finally, MT1DP-inhibited in vivo liver cancer cell growth could be rescued by a combination of overexpression of FoxA1, Runx2 and YAP. Taken together, the close relationship between Rnux2 and YAP plays a pro-carcinogenetic role in liver cancer cells through inhibiting tumor suppressor lncRNA, MT1DP in a FoxA1 dependent manner.

Runx2 activates PI3K/Akt signaling via mTORC2 regulation in invasive breast cancer cells

Introduction

The Runt-related transcription factor Runx2 is critical for skeletal development but is also aberrantly expressed in breast cancers, and promotes cell growth and invasion. A de-regulated serine/threonine kinase Akt signaling pathway is implicated in mammary carcinogenesis and cell survival; however, the mechanisms underlying Runx2 role in survival of invasive breast cancer cells are still unclear.

Methods

The phenotypic analysis of Runx2 function in cell survival was performed by gene silencing and flow cytometric analysis in highly invasive MDA-MB-231 and SUM-159-PT mammary epithelial cell lines. The expression analysis of Runx2 and pAkt (serine 473) proteins in metastatic breast cancer specimens was performed by immunohistochemistry. The mRNA and protein levels of kinases and phosphatases functional in Akt signaling were determined by real-time PCR and Western blotting, while DNA-protein interaction was studied by chromatin immunoprecipitation assays.

Results

The high Runx2 levels in invasive mammary epithelial cell lines promoted cell survival in Akt phosphorylation (pAkt-serine 473) dependent manner. The analysis of kinases and phosphatases associated with pAkt regulation revealed that Runx2 promotes pAkt levels via mammalian target of rapamycin complex-2 (mTORC2). The recruitment of Runx2 on mTOR promoter coupled with Runx2-dependent expression of mTORC2 component Rictor defined Runx2 function in pAkt-mediated survival of invasive breast cancer cells.

Conclusions

Our results identified a novel mechanism of Runx2 regulatory crosstalk in Akt signaling that could have important consequences in targeting invasive breast cancer-associated cell survival.

Inhibition of RUNX2 transcriptional activity blocks the proliferation, migration and invasion of epithelial ovarian carcinoma cells

Previously, we have identified the RUNX2 gene as hypomethylated and overexpressed in post-chemotherapy (CT) primary cultures derived from serous epithelial ovarian cancer (EOC) patients, when compared to primary cultures derived from matched primary (prior to CT) tumors. However, we found no differences in the RUNX2 methylation in primary EOC tumors and EOC omental metastases, suggesting that DNA methylation-based epigenetic mechanisms have no impact on RUNX2 expression in advanced (metastatic) stage of the disease. Moreover, RUNX2 displayed significantly higher expression not only in metastatic tissue, but also in high-grade primary tumors and even in low malignant potential tumors. Knockdown of the RUNX2 expression in EOC cells led to a sharp decrease of cell proliferation and significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as various genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon RUNX2 suppression, while a number of pro-apoptotic genes and some EOC tumor suppressor genes were induced. Taken together, our data are indicative for a strong oncogenic potential of the RUNX2 gene in serous EOC progression and suggest that RUNX2 might be a novel EOC therapeutic target. Further studies are needed to more completely elucidate the functional implications of RUNX2 and other members of the RUNX gene family in ovarian tumorigenesis.