Runx3 protects gastric epithelial cells against epithelial-mesenchymal transition-induced cellular plasticity and tumorigenicity

RUNX transcription factors: biological functions and implications in cancer

Runt-related transcription factors (RUNX) are a family of transcription factors that are essential for normal and malignant hematopoietic processes. Their most widely recognized role in malignancy is to promote the occurrence and development of acute myeloid leukemia. However, it is worth noting that during the last decade, studies of RUNX proteins in solid tumors have made considerable progress, suggesting that these proteins are directly involved in different stages of tumor development, including tumor initiation, progression, and invasion. RUNX proteins also play a role in tumor angiogenesis, the maintenance of tumor cell stemness, and resistance to antitumor drugs. These findings have led to the consideration of RUNX as a tumor biomarker. All RUNX proteins are involved in the occurrence and development of solid tumors, but the role of each RUNX protein in different tumors and the major signaling pathways involved are complicated by tumor heterogeneity and the interacting tumor microenvironment. Understanding how the dysregulation of RUNX in tumors affects normal biological processes is important to elucidate the molecular mechanisms by which RUNX affects malignant tumors.

Harnessing function of EMT in cancer drug resistance: a metastasis regulator determines chemotherapy response

Epithelial-mesenchymal transition (EMT) is a complicated molecular process that governs cellular shape and function changes throughout tissue development and embryogenesis. In addition, EMT contributes to the development and spread of tumors. Expanding and degrading the surrounding microenvironment, cells undergoing EMT move away from the main location. On the basis of the expression of fibroblast-specific protein-1 (FSP1), fibroblast growth factor (FGF), collagen, and smooth muscle actin (-SMA), the mesenchymal phenotype exhibited in fibroblasts is crucial for promoting EMT. While EMT is not entirely reliant on its regulators like ZEB1/2, Twist, and Snail proteins, investigation of upstream signaling (like EGF, TGF-β, Wnt) is required to get a more thorough understanding of tumor EMT. Throughout numerous cancers, connections between tumor epithelial and fibroblast cells that influence tumor growth have been found. The significance of cellular crosstalk stems from the fact that these events affect therapeutic response and disease prognosis. This study examines how classical EMT signals emanating from various cancer cells interfere to tumor metastasis, treatment resistance, and tumor recurrence.

Molecular Insight into Gastric Cancer Invasion-Current Status and Future Directions

Gastric cancer (GC) is one of the most common malignancies worldwide. There has been no efficient therapy for stage IV GC patients due to this disease's heterogeneity and dissemination ability. Despite the rapid advancement of molecular targeted therapies, such as HER2 and immune checkpoint inhibitors, survival of GC patients is still unsatisfactory because the understanding of the mechanism of GC progression is still incomplete. Invasion is the most important feature of GC metastasis, which causes poor mortality in patients. Recently, genomic research has critically deepened our knowledge of which gene products are dysregulated in invasive GC. Furthermore, the study of the interaction of GC cells with the tumor microenvironment has emerged as a principal subject in driving invasion and metastasis. These results are expected to provide a profound knowledge of how biological molecules are implicated in GC development. This review summarizes the advances in our current understanding of the molecular mechanism of GC invasion. We also highlight the future directions of the invasion therapeutics of GC. Compared to conventional therapy using protease or molecular inhibitors alone, multi-therapy targeting invasion plasticity may seem to be an assuring direction for the progression of novel strategies.

Multiple Roles of the RUNX Gene Family in Hepatocellular Carcinoma and Their Potential Clinical Implications

Hepatocellular carcinoma (HCC) is one of the most frequent cancers in humans, characterised by a high resistance to conventional chemotherapy, late diagnosis, and a high mortality rate. It is necessary to elucidate the molecular mechanisms involved in hepatocarcinogenesis to improve diagnosis and treatment outcomes. The Runt-related (RUNX) family of transcription factors (RUNX1, RUNX2, and RUNX3) participates in cardinal biological processes and plays paramount roles in the pathogenesis of numerous human malignancies. Their role is often controversial as they can act as oncogenes or tumour suppressors and depends on cellular context. Evidence shows that deregulated RUNX genes may be involved in hepatocarcinogenesis from the earliest to the latest stages. In this review, we summarise the topical evidence on the roles of RUNX gene family members in HCC. We discuss their possible application as non-invasive molecular markers for early diagnosis, prognosis, and development of novel treatment strategies in HCC patients.

Resveratrol induces the growth inhibition of CDX-deficient gastric cancer cells using CDX2 and RUNX3 via the β-catenin/TCF4 signaling pathway

This study aimed to determine the expression levels of runt-related transcription factor 3 (RUNX3) and caudal-related homeobox 2 (CDX2) in patients with chronic gastritis, intestinal metaplasia, atypical hyperplasia, and gastric cancer (GC). To analyze the overexpression of CDX2 and the effects of resveratrol (Res) on MKN7 and TMK1 cells, immunohistochemical staining was performed to determine the protein expression levels in tissue samples. The biological activity of MKN7 and TMK1 cells was determined. Relative mRNA and protein expression levels were also determined. RUNX3 expression was positively correlated with CDX2 expression and negatively correlated with β-catenin and transcription factor 4 (TCF-4) levels in GC tissues. Interestingly, RUNX3 expression was negatively correlated with CDX2 expression in other tissues. CDX2 overexpression or Res treatment inhibited cell proliferation, migration, and invasion, while inducing cell apoptosis. Furthermore, RUNX3 and B-cell lymphoma-2 (Bcl-2)-associated X protein (Bax) expression levels were increased, while those of of β-catenin, TCF-4, and Bcl-2 were decreased in the CDX2 group. Upon treatment with lithium chloride (LiCl), the proliferation, migration, and invasion of CDX2-overexpressing MKN7 and TMK1 cells were enhanced. Our results indicate that Res inhibits the growth of MKN7 and TMK1 cells by increasing RUNX3 and CDX2 expression levels, with the potential involvement of the β-catenin/TCF-4 signaling pathway.

The lncRNA HOTAIR: a pleiotropic regulator of epithelial cell plasticity

The epithelial-to-mesenchymal transition (EMT) is a trans-differentiation process that endows epithelial cells with mesenchymal properties, including motility and invasion capacity; therefore, its aberrant reactivation in cancerous cells represents a critical step to gain a metastatic phenotype. The EMT is a dynamic program of cell plasticity; many partial EMT states can be, indeed, encountered and the full inverse mesenchymal-to-epithelial transition (MET) appears fundamental to colonize distant secondary sites. The EMT/MET dynamics is granted by a fine modulation of gene expression in response to intrinsic and extrinsic signals. In this complex scenario, long non-coding RNAs (lncRNAs) emerged as critical players. This review specifically focuses on the lncRNA HOTAIR, as a master regulator of epithelial cell plasticity and EMT in tumors. Molecular mechanisms controlling its expression in differentiated as well as trans-differentiated epithelial cells are highlighted here. Moreover, current knowledge about HOTAIR pleiotropic functions in regulation of both gene expression and protein activities are described. Furthermore, the relevance of the specific HOTAIR targeting and the current challenges of exploiting this lncRNA for therapeutic approaches to counteract the EMT are discussed.

Molecular mechanisms of microRNA-301a during tumor progression and metastasis

Cancer is known as one of the leading causes of human deaths globally. Late diagnosis is considered as one of the main reasons for the high mortality rate among cancer patients. Therefore, the introduction of early diagnostic tumor markers can improve the efficiency of therapeutic modalities. MicroRNAs (miRNAs) have a key role in regulation of cell proliferation and apoptosis. MiRNAs deregulation has been frequently reported during tumor progressions. Since, miRNAs have a high stability in body fluids; they can be used as the reliable non-invasive tumor markers. Here, we discussed the role of miR-301a during tumor progressions. MiR-301a mainly functions as an oncogene via the modulation of transcription factors, autophagy, epithelial-mesenchymal transition (EMT), and signaling pathways. This review paves the way to suggest miR-301a as a non-invasive marker for the early tumor diagnosis. MiR-301a can also be suggested as an effective target in cancer therapy.

RUNX3 in Stem Cell and Cancer Biology

The runt-related transcription factors (RUNX) play prominent roles in cell cycle progression, differentiation, apoptosis, immunity and epithelial-mesenchymal transition. There are three members in the mammalian RUNX family, each with distinct tissue expression profiles. RUNX genes play unique and redundant roles during development and adult tissue homeostasis. The ability of RUNX proteins to influence signaling pathways, such as Wnt, TGFβ and Hippo-YAP, suggests that they integrate signals from the environment to dictate cell fate decisions. All RUNX genes hold master regulator roles, albeit in different tissues, and all have been implicated in cancer. Paradoxically, RUNX genes exert tumor suppressive and oncogenic functions, depending on tumor type and stage. Unlike RUNX1 and 2, the role of RUNX3 in stem cells is poorly understood. A recent study using cancer-derived RUNX3 mutation R122C revealed a gatekeeper role for RUNX3 in gastric epithelial stem cell homeostasis. The corpora of RUNX3^R122C/R122C mice showed a dramatic increase in proliferating stem cells as well as inhibition of differentiation. Tellingly, RUNX3^R122C/R122C mice also exhibited a precancerous phenotype. This review focuses on the impact of RUNX3 dysregulation on (1) stem cell fate and (2) the molecular mechanisms underpinning early carcinogenesis.

Targeted disruption of mitochondria potently reverses multidrug resistance in cancer therapy

BACKGROUND AND PURPOSE

Multidrug resistance (MDR) is the main obstacle to cancer therapy. Ample evidence shows that ATP-binding cassette (ABC) transporters and high-energy state substantially relate to cancer drug resistance. Our previous work reported an engineered therapeutic protein named PAK, which selectively inhibited tumor progression by targeting mitochondria.

EXPERIMENTAL APPROACH

Here, we studied the effects of PAK on reversing drug resistance in MDR phenotypic cells and xenograft mice models. The effects of PAK on the process of mitochondrial energy production, ABC transporters expression, and the drugs enrichment in cancer cells were further investigated. RNA-seq and co-immunoprecipitation were employed to analyze the mechanism of PAK on the redistribution of ABC transporters.

KEY RESULTS

PAK promoted the enrichment of drugs in MDR cancer cells, thus enhancing the sensitivity of cancer cells to chemotherapy. Furthermore, PAK was colocalized in the mitochondria and initiated mitochondrial injury by selectively inhibiting the mitochondrial complex V. Besides, ABCB1 and ABCC1 were found to be redistributed from the plasma membrane to the cytoplasm through the disruption of lipid rafts, which was attributed to the low energy state and the decrease of cholesterol levels.

CONCLUSIONS AND IMPLICATIONS

Our results revealed a previously unrecognized drug resistance reversal pattern and suggested mitochondria as a clinically relevant target for the treatment of MDR malignant tumors.

Infection with a hypervirulent strain of Helicobacter pylori primes gastric cells toward intestinal transdifferentiation

BACKGROUND

Intestinal metaplasia, gastric-to-intestinal transdifferentiation, occurs as a result of the misexpression of certain regulatory factors, leading to genetic reprogramming. Here, we have evaluated the H. pylori-induced expression patterns of these candidate genes.

METHODS

The expression levels of 1) tissue-specific transcription factors (RUNX3, KLF5, SOX2, SALL4, CDX1 and CDX2), 2) stemness factors (TNFRSF19, LGR5, VIL1) and 3) tissue-specific mucins (MUC5AC, MUC2) were evaluated by quantitative real-time PCR in gastric primary cells (GPCs), in parallel with two gastric cancer (MKN45 and AGS) cell lines, up to 96h following H. pylori infection.

RESULTS

Following H. pylori infection of GPCs, RUNX3 declined at 24h post infection (-6.2 ± 0.3) and remained downregulated for up to 96h. Subsequently, overexpression of self-renewal and pluripotency transcription factors, KLF5 (3.6 ± 0.2), SOX2 (7.6 ± 0.5) and SALL4 (4.3 ± 0.2) occurred. The expression of TNFRSF19 and LGR5, demonstrated opposing trends, with an early rise of the former (4.5 ± 0.3) at 8h, and a simultaneous fall of the latter (-1.8 ± 0.5). This trend was reversed at 96h, with the decline in TNFRSF19 (-5.5 ± 0.2), and escalation of LGR5 (2.6 ± 0.2) and VIL1 (1.8 ± 0.3). Ultimately, CDX1 and CDX2 were upregulated by 1.9 and 4.7-fold, respectively. The above scenario was, variably observed in MKN45 and AGS cells.

CONCLUSION

Our data suggests an interdependent gene regulatory network, induced by H. pylori infection. This interaction begins with the downregulation of RUNX3, upregulation of self-renewal and pluripotency transcription factors, KLF5, SOX2 and SALL4, leading to the downregulation of TNFRSF19, upregulation of LGR5 and aberrant expression of intestine-specific transcription factors, potentially facilitating the process of gastric-to-intestinal transdifferentiation.

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.

Diagnostic molecular markers predicting aggressive potential in low-grade prostate cancer

Currently, clinicians rely on clinical nomograms to stratify progression risk at the time of diagnosis in patients with prostate cancer (CaP). However, these tools may not accurately distinguish aggressive potential in low-grade CaP. The current study determined the diagnostic potential of 3 molecular markers (ROCK1, RUNX3, and miR-301a) in terms of their ability to identify which low-grade tumors are likely to progress. Real-time PCR and immunohistochemical analysis were used to assess ROCK1, RUNX3, and miR-301a expression profiles in 118 serum and needle biopsy specimens. Expressions of ROCK1 and miR-301a were found to be significantly higher in Gleason 6 and 7 CaP as compared to BPH, while an inverse trend was observed with RUNX3. Further, incorporation of all 3 molecular markers significantly improved clinical nomograms' diagnostic accuracy and correlated with disease progression. Hence, in conclusion, the inclusion of these 3 molecular markers identified aggressive phenotype and predicted disease progression in low-grade CaP tumors at the time of diagnosis.

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.

Clinicopathological characteristics of mucin phenotype and its relation to the malignant potential in early differentiated gastric adenocarcinoma

Objectives

Mucin phenotype is a tool to classify gastric cancer, but the relationship between mucin phenotype and its malignancy is still controversial. This study aimed to clarify the relationship between mucin phenotype and the malignant potential of gastric cancer.

Methods

A total of 82 cases of early-stage differentiated adenocarcinoma (submucosal invasion cases) obtained from surgeries were studied by immunohistochemistry. Gastric mucin phenotype and E-cadherin expression were analyzed in the mucosal and submucosal layer. E-cadherin expression was analyzed by using imaging software (ImageJ) for objective data analysis. Furthermore, the mucin phenotypic shift was analyzed from mucosa to submucosa.

Results

We found that: (1) tumors with intestinal mucin phenotype had statistically more venous invasion in the submucosal lesion; (2) tumors with an intestinal phenotype that showed venous invasion in the submucosal lesion had a higher percentage of tumors that showed loss of phenotype; (3) no dominant change in E-cadherin expression was observed from the mucosa to submucosa.

Conclusion

Tumors with loss of phenotype and submucosal intestinal phenotype showed predominantly more venous invasion, so examining the identification of phenotypes and phenotype shifts can be expected to be a factor that influences treatment strategies after endoscopic treatment or after surgical resection.

Gene expression analysis of human prostate cell lines with and without tumor metastasis suppressor CD82

BACKGROUND

Tetraspanin CD82 is a tumor metastasis suppressor that is known to down regulate in various metastatic cancers. However, the exact mechanism by which CD82 prevents cancer metastasis is unclear. This study aims to identify genes that are regulated by CD82 in human prostate cell lines.

METHODS

We used whole human genome microarray to obtain gene expression profiles in a normal prostate epithelial cell line that expressed CD82 (PrEC-31) and a metastatic prostate cell line that does not express CD82 (PC3). Then, siRNA silencing was used to knock down CD82 expression in PrEC-31 while CD82 was re-expressed in PC3 to acquire differentially-expressed genes in the respective cell line.

RESULTS

Differentially-expressed genes with a P < 0.05 were identified in 3 data sets: PrEC-31 (+CD82) vs PrEC-31(-CD82), PC3-57 (+CD82) vs. PC3-5 V (-CD82), and PC3-29 (+CD82) vs. PC3-5 V (-CD82). Top 25 gene lists did not show overlap within the data sets, except (CALB1) the calcium binding protein calbindin 1 which was significantly up-regulated (2.8 log fold change) in PrEC-31 and PC3-29 cells that expressed CD82. Other most significantly up-regulated genes included serine peptidase inhibitor kazal type 1 (SPINK1) and polypeptide N-acetyl galactosaminyl transferase 14 (GALNT14) and most down-regulated genes included C-X-C motif chemokine ligand 14 (CXCL14), urotensin 2 (UTS2D), and fibroblast growth factor 13 (FGF13). Pathways related with cell proliferation and angiogenesis, migration and invasion, cell death, cell cycle, signal transduction, and metabolism were highly enriched in cells that lack CD82 expression. Expression of two mutually inclusive genes in top 100 gene lists of all data sets, runt-related transcription factor (RUNX3) and trefoil factor 3 (TFF3), could be validated with qRT-PCR.

CONCLUSION

Identification of genes and pathways regulated by CD82 in this study may provide additional insights into the role that CD82 plays in prostate tumor progression and metastasis, as well as identify potential targets for therapeutic intervention.

RUNX3-dependent oxidative epithelial-to-mesenchymal transition in methamphetamine-induced chronic lung injury

Lung toxicity is the main cause of the death from methamphetamine (MA) abuse, but its mechanism has remained unclear. The purpose of our study was to investigate if MA can induce epithelial-to-mesenchymal transition (EMT) and if RUNX3 is involved in oxidative EMT in MA-induced chronic lung injury. The rats were divided into the control group and MA group. Extracted lungs were used for morphological measurements and Western blot. The alveolar epithelial cells were cultured or transfected and then treated with MA or/and N-acetyl cysteine (NAC) followed by flow cytometry, Western blot, and immunohistochemistry. Chronic exposure to MA resulted in the lower growth ratio of weight, increased right ventricular index, thickened alveolar walls, and reduced number of alveolar sacs. Long-term administration with MA caused oxidative stress and pulmonary EMT. NAC increased RUNX3 and alleviated EMT. However, after knockdown of RUNX3, reactive oxygen species (ROS) levels were significantly upregulated, indicating that RUNX3 was closely related to oxidative stress. Knockdown of RUNX3 aggravated MA-induced EMT by activating RUNX3-dependent TGF-β signaling. Therefore, RUNX3 may be the key to oxidative EMT in methamphetamine-induced chronic lung injury.

Circular RNA circREPS2 Acts as a Sponge of miR-558 to Suppress Gastric Cancer Progression by Regulating RUNX3/β-catenin Signaling

Circular RNAs (circRNAs) play an essential regulatory role in multiple cancers. However, the role of a large number of circRNAs in gastric cancer (GC) is still unknown. Here, hsa_circ_0139996 (circREPS2), a novel circRNA that was significantly downregulated in GC, was selected for further investigation. circREPS2 was validated and analyzed by DNA sequencing and quantitative real-time PCR. The roles of circREPS2 in GC cells were verified by gain- and loss-of-function experiments. Bioinformatics analysis, luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays were performed to evaluate the functional mechanism of circREPS2 on microRNA-558 (miR-558)/RUNX3/β-catenin axis in GC cells. In the present study, we found that circREPS2 was downregulated in GC tissues and cell lines. Low expression of circREPS2 was associated with a higher tumor-node-metastasis (TNM) stage, poor tumor differentiation, and larger tumor size in GC patients. Functionally, circREPS2 significantly inhibited GC cell proliferation, migration, invasion, and epithelial-mesenchymal transformation (EMT) in vitro and tumorigenesis in vivo. Furthermore, our data demonstrated that circREPS2 acted as a miR-558 sponge and upregulated RUNX3 expression to inactivate β-catenin signaling in GC cells. In conclusion, circREPS2 suppresses the progression of GC via miR-558/RUNX3/β-catenin signaling and is a novel promising biomarker and target for GC treatment.

Inhibition of PIM1 attenuates the stem cell-like traits of breast cancer cells by promoting RUNX3 nuclear retention

Finding out the driver gene critical for the maintenance of breast cancer stem cells (BrCSCs) is important for designing a new strategy to eradicate these cells to improve patient's prognosis. Here, in our study, we revealed that PIM1, an oncogenic serine‐threonine kinase and a well‐proven contributor to the tumorigenesis of breast cancer, was involved in BrCSCs regulation and promised to be a new target for eradicating BrCSCs. In brief, PIM1 could enhance the stem cell–like traits of breast cancer cells by promoting the phosphorylation and cytoplasmic localization of RUNX3. The nuclear dislocation of RUNX3 disabled this tumour suppressor and led to breast cancer cells gaining stem cell–like traits. Inhibition of PIM1 significantly induced the nuclear retention of RUNX3, recovered its transcriptional function and attenuated the stem cell–like properties of breast cancer cells. Those findings deepened our understanding of PIM1's oncogenic effect, underlining the significance of PIM1 in designing a new strategy aimed at BrCSCs.

Immunological Aspects of the Tumor Microenvironment and Epithelial-Mesenchymal Transition in Gastric Carcinogenesis

Infection with Helicobacter pylori, a Gram-negative, microaerophilic pathogen often results in gastric cancer in a subset of affected individuals. This explains why H. pylori is the only bacterium classified as a class I carcinogen by the World Health Organization. Several studies have pinpointed mechanisms by which H. pylori alters signaling pathways in the host cell to cause diseases. In this article, the authors have reviewed 234 studies conducted over a span of 18 years (2002-2020). The studies investigated the various mechanisms associated with gastric cancer induction. For the past 1.5 years, researchers have discovered new mechanisms contributing to gastric cancer linked to H. pylori etiology. Alongside alteration of the host signaling pathways using oncogenic CagA pathways, H. pylori induce DNA damage in the host and alter the methylation of DNA as a means of perturbing downstream signaling. Also, with H. pylori, several pathways in the host cell are activated, resulting in epithelial-to-mesenchymal transition (EMT), together with the induction of cell proliferation and survival. Studies have shown that H. pylori enhances gastric carcinogenesis via a multifactorial approach. What is intriguing is that most of the targeted mechanisms and pathways appear common with various forms of cancer.

RUNX3 inhibits the invasion and migration of esophageal squamous cell carcinoma by reversing the epithelial‑mesenchymal transition through TGF‑β/Smad signaling

Runt‑related transcription factor 3 (RUNX3) is a candidate tumor suppressor, and its inactivation may play a crucial role in the carcinogenesis process of numerous cancer types, including esophageal squamous cell carcinoma (ESCC). We previously revealed that RUNX3 inactivation was correlated with lymph node metastasis (LNM) and ESCC recurrence. However, the exact mechanisms of this process are still under investigation. The aim of the present study was to examine the potential roles and underlying molecular mechanisms of RUNX3 in ESCC metastasis and the epithelial‑mesenchymal transition (EMT). According to the results, RUNX3 expression in ESCC tissue was significantly reduced compared with that in adjacent normal tissue (0.50±0.20 vs. 0.83±0.16; P<0.001). In addition, statistical analysis revealed a close association between decreased RUNX3 expression and T status (P=0.027) and LNM (P=0.017) in ESCC patients. Pearson's correlation coefficient analysis was then used to evaluate correlations between RUNX3 and EMT‑related marker expression. The results revealed that RUNX3 expression in ESCC tissues was negatively correlated with the expression of N‑cadherin (r=‑0.429; P<0.01) and Snail (r=‑0.364; P<0.01) and positively correlated with the expression of E‑cadherin (r=0.580; P<0.01). Moreover, Eca109 and EC9706 cell invasion, migration, MMP‑9 expression and EMT were significantly inhibited by RUNX3 overexpression. Notably, further analysis revealed that RUNX3 overexpression markedly inhibited the phosphorylation of Smad2/3; RUNX3‑overexpressing cells also displayed less sensitivity to TGF‑β1‑induced EMT than control cells. Thus, RUNX3 may inhibit the invasion and migration of ESCC cells by reversing EMT through TGF‑β/Smad signaling and may be useful as a therapeutic target.

Inflammatory and mitogenic signals drive interleukin 23 subunit alpha (IL23A) secretion independent of IL12B in intestinal epithelial cells

The heterodimeric cytokine interleukin-23 (IL-23 or IL23A/IL12B) is produced by dendritic cells and macrophages and promotes the proinflammatory and regenerative activities of T helper 17 (Th17) and innate lymphoid cells. A recent study has reported that IL-23 is also secreted by lung adenoma cells and generates an inflammatory and immune-suppressed stroma. Here, we observed that proinflammatory tumor necrosis factor (TNF)/NF-κB and mitogen-activated protein kinase (MAPK) signaling strongly induce IL23A expression in intestinal epithelial cells. Moreover, we identified a strong crosstalk between the NF-κB and MAPK/ERK kinase (MEK) pathways, involving the formation of a transcriptional enhancer complex consisting of proto-oncogene c-Jun (c-Jun), RELA proto-oncogene NF-κB subunit (RelA), RUNX family transcription factor 1 (RUNX1), and RUNX3. Collectively, these proteins induced IL23A secretion, confirmed by immunoprecipitation of endogenous IL23A from activated human colorectal cancer (CRC) cell culture supernatants. Interestingly, IL23A was likely secreted in a noncanonical form, as it was not detected by an ELISA specific for heterodimeric IL-23 likely because IL12B expression is absent in CRC cells. Given recent evidence that IL23A promotes tumor formation, we evaluated the efficacy of MAPK/NF-κB inhibitors in attenuating IL23A expression and found that the MEK inhibitor trametinib and BAY 11-7082 (an IKKα/IκB inhibitor) effectively inhibited IL23A in a subset of human CRC lines with mutant KRAS or BRAFV600E mutations. Together, these results indicate that proinflammatory and mitogenic signals dynamically regulate IL23A in epithelial cells. They further reveal its secretion in a noncanonical form independent of IL12B and that small-molecule inhibitors can attenuate IL23A secretion.

RYK, a receptor of noncanonical Wnt ligand Wnt5a, is positively correlated with gastric cancer tumorigenesis and potential of liver metastasis

Gastric cancer (GC) is the most prevalent human cancer around the globe. In GC, Wnt signaling is deregulated, and receptor-like tyrosine kinase (RYK) coreceptors have been identified to interact with noncanonical Wnt ligand Wnt5a. We, therefore, aimed to evaluate the role of RYK in GC development and metastasis. GC tumor samples were collected from 250 GC patients. Expressions of RYK, as well as markers for the epithelial-mesenchymal transition (EMT), such as N-cadherin and E-cadherin, were subjected to correlation analysis with clinicopathological features. Endogenous RYK expression levels were compared in GC cell lines with ascending metastatic potentials followed by stable RYK knockdown. Effect of RYK knockdown on GC cell migration, invasion, and EMT phenotype were assessed in vitro, and on GC tumor growth in vivo in a xenograft rodent model. Particularly, liver metastasis potential of tail vein-injected GC cells was also analyzed following RYK knockdown. RYK was highly correlated with liver metastasis of GC tumors and the expression profiles of EMT markers toward the mesenchymal tendency. RYK expression was also positively correlated with the metastasis potential of GC cells. RYK knockdown not only inhibited migration, invasion, and EMT of GC cells in vitro, but also suppressed tumorigenesis and liver metastasis of GC cells in vivo using the mouse xenograft model. RYK is highly correlated with GC tumorigenesis and potential of liver metastasis, suggesting it may be a novel oncogenic factor of the noncanonical Wnt signaling pathway contributing to GC.NEW & NOTEWORTHY RYK is highly correlated with gastric cancer tumorigenesis and the potential of liver metastasis, suggesting it may be a novel oncogenic factor of the noncanonical Wnt signaling pathway contributing to gastric cancer.

HIF-1ɑ-regulated miR-1275 maintains stem cell-like phenotypes and promotes the progression of LUAD by simultaneously activating Wnt/β-catenin and Notch signaling

Rationale: Cancer stem cells (CSCs) are considered to be essential for tumorigenesis, recurrence, and metastasis and therefore serve as a biomarker for tumor progression in diverse cancers. Recent studies have illustrated that specific miRNAs exhibit novel therapeutic potential by controlling CSC properties. miR-1275 is upregulated in lung adenocarcinoma (LUAD) and enhances its stemness. However, the underlying mechanisms have not been elucidated.

Methods: miRNA expression microarray of LUAD and adjacent nontumor tissues was used to identify miRNAs involved in LUAD malignant progression. miR-1275 expression level was determined using quantitative real-time PCR (RT-qPCR) and in situ hybridization (ISH), and its correlation with clinicopathological characteristics was analyzed in LUAD specimens. The upstream regulator of miR-1275 was validated by chromatin immunoprecipitation (ChIP). The biological functions and underlying mechanisms of miR-1275 were investigated both in vitro and in vivo.

Results: MiR-1275 was highly upregulated in lung cancer cell lines and LUAD tissues. Overexpression of miR-1275 in lung cancer patients was associated with shorter overall- and recurrence-free-survival. Proto-oncogene HIF-1ɑ was identified as the transcription mediator of miR-1275. Activation of Wnt/β-catenin and Notch signaling by miR-1275 was found to enhance the stemness of LUAD cells, while antagonizing miR-1275 or suppressing Wnt/β-catenin and Notch pathways potently reversed miR-1275-induced pathway co-activation and stemness. Enhanced stemness dramatically promoted tumorigenicity, recurrence, and metastasis. miR-1275 directly targeted multiple antagonists of Wnt/β-catenin and Notch pathways, including DKK3, SFRP1, GSK3β, RUNX3, and NUMB, respectively, which resulted in signaling activation.

Conclusions: Our findings identified miR-1275 as a potential oncogene in LUAD that exerts its tumorigenic effect through co-activating Wnt/β-catenin and Notch signaling pathways. Thus, HIF-1ɑ-regulated miR-1275 might be a potential therapeutic target for LUAD.

Primary and Metastatic Pancreatic Cancer Cells Exhibit Differential Migratory Potentials

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) is characterized by early metastatic spread in more than 50% of patients. In this study, we sought to understand the migratory properties of (non)metastatic PDAC cells and determine whether the migration of cancer stem cell (CSC) populations accounts for the aggressive nature of this disease.

METHODS

The migratory abilities of primary and metastatic PDAC cell lines were investigated using a microfluidic device and time-lapse photography. The velocity, time of delay of mobilization, and number of migratory cells were analyzed. Cancer stem cell subpopulations were isolated by fluorescence-activated cell sorting and their migratory properties compared with their non-CSC counterparts.

RESULTS

Primary cancer cells exhibited higher velocities, greater number of migratory cells, and a shorter time of delay of mobilization in comparison to metastatic cell lines. Characterization of CSC populations revealed primary PDAC cell lines were composed of fewer CD133 and CD24CD44 CSC subpopulations than metastatic cells. Moreover, migratory analysis of CSC subpopulations revealed lower velocities, fewer migratory cells, and a greater time of delay of mobilization than non-CSC.

CONCLUSIONS

Primary cancer cells demonstrate enhanced migratory abilities in comparison to metastatic PDAC cells. Those differences may result from lower CSC subpopulations in primary cells because CSC populations demonstrated impaired migratory abilities in contrast to non-CSC.

Ethanol promotes alcohol-related colorectal cancer metastasis via the TGF-β/RUNX3/Snail axis by inducing TGF-β1 upregulation and RUNX3 cytoplasmic mislocalization

BACKGROUND

Alcohol intake is a well-known lifestyle risk factor for CRC, and an increasing number of studies have revealed that alcohol intake is also tightly associated with CRC metastasis. However, the effect of alcohol on CRC metastasis and its underlying mechanism remain unclear.

METHODS

A retrospective cohort study was performed to investigate the characteristics of patients with alcohol-related CRC. The effects of ethanol on the biological behaviours of CRC cells were assessed through in vivo and in vitro assays using the Lieber-DeCarli ethanol liquid diet and ethanol, respectively. The ethanol-mediated signalling pathway and downstream factors were screened through ELISA, western blot, immunofluorescence and co-immunoprecipitation.

FINDINGS

Most patients with alcohol-related CRC, particularly those with tumour metastasis, were characterized by a notably higher circulating ethanol level and a lower systemic acetaldehyde level. Moreover, CRC cells accumulated in ethanol, but not acetaldehyde, to notably higher levels compared with adjacent normal cells. Alcohol intake significantly promoted CRC metastasis via the ethanol-mediated TGF-β/Smad/Snail axis, and ethanol induced the cytoplasmic mislocalization of RUNX3 and further promoted the aggressiveness of CRC by targeting Snail. Pirfenidone (PFD) significantly eliminated the effects of ethanol on CRC metastasis by specifically blocking TGF-β signalling.

INTERPRETATION

Alcohol intake plays a vital role in CRC metastasis via the ethanol-mediated TGF-β/RUNX3/Snail axis, and PFD might be a novel therapeutic management strategy for CRC.

Circulating methylated RUNX3 and SFRP1 genes as a noninvasive panel for early detection of colorectal cancer

OBJECTIVE

This study was conducted to assess the methylation status of runt-related transcription factor 3 (RUNX3) and secreted frizzled-related protein 1 (SFRP1) genes in paired tissue and serum samples of colorectal cancer (CRC), adenomatous, and control subjects and elucidate the association between methylation status on RUNX3 and SFRP1 mRNA expression.

METHODS

Methylation status of RUNX3 and SFRP1 in paired tissue and serum samples and RUNX3 and SFRP1 mRNA expression in tissue from 85 patients with CRC, 40 with adenoma, and 40 healthy controls were determined using methylation-specific PCR and reverse transcription PCR.

RESULTS

The frequency RUNX3 and SFRP1 genes methylation was significantly higher in both tissues and serum of CRC patients and was significantly associated with absence of its corresponding mRNA expression. The concordance between tissue and serum methylation status was 94.4% for RUNX3 and 94.3% for SFRP1. Tissue RUNX3 methylation status detected CRC with 63.53% sensitivity and 80.00% specificity, while serum RUNX3 methylation status detected CRC with 60.00% sensitivity and 82.50% specificity. Tissue SFRP1 methylation status showed a sensitivity of 82.35% and specificity of 65.00%, while serum SFRP1 methylation status showed a sensitivity of 77.65% and specificity of 70.00% in detection of CRC. RUNX3/SFRP1/carcinoembryonic antigen (CEA) panel identified CRC with sensitivity of 89.41% in tissue and 84.71% in serum.

CONCLUSION

Our results verified the reliability of using serum RUNX3 and SFRP1 methylation status as a noninvasive biomarker for diagnosis of CRC and that combined detection of RUNX3/SFRP1/CEA panel might be a promising strategy for early detection of CRC.

ROS and Lipid Droplet accumulation induced by high glucose exposure in healthy colon and Colorectal Cancer Stem Cells

Lipid Droplets (LDs) are emerging as crucial players in colon cancer development and maintenance. Their expression has been associated with high tumorigenicity in Cancer Stem Cells (CSCs), so that they have been proposed as a new functional marker in Colorectal Cancer Stem Cells (CR-CSCs). They are also indirectly involved in the modulation of the tumor microenvironment through the production of pro-inflammatory molecules. There is growing evidence that a possible connection between metabolic alterations and malignant transformation exists, although the effects of nutrients, primarily glucose, on the CSC behavior are still mostly unexplored. Glucose is an essential fuel for cancer cells, and the connections with LDs in the healthy and CSC populations merit to be more deeply investigated. Here, we showed that a high glucose concentration activated the PI3K/AKT pathway and increased the expression of CD133 and CD44v6 CSC markers. Additionally, glucose was responsible for the increased amount of Reactive Oxygen Species (ROS) and LDs in both healthy and CR-CSC samples. We also investigated the gene modulations following the HG treatment and found out that the healthy cell gene profile was the most affected. Lastly, Atorvastatin, a lipid-lowering drug, induced the highest mortality on CR-CSCs without affecting the healthy counterpart.

miR-301a promotes lung tumorigenesis by suppressing Runx3

BACKGROUND

Our previous report demonstrated that genetic ablation of miR-301a reduces Kras-driven lung tumorigenesis in mice. However, the impact of miR-301a on host anti-tumor immunity remains unexplored. Here we assessed the underlying molecular mechanisms of miR-301a in the tumor microenvironment.

METHODS

The differentially expressed genes were identified by using deep sequencing. The immune cell counts, and cytokines expression were analyzed by realtime PCR, immunohistochemistry and flow cytometry. The role of miR-301a/Runx3 in lung tumor was evaluated on cell growth, migration and invasion. The function of miR-301a/Runx3 in regulating tumor microenvironment and tumor metastasis were evaluated in Kras transgenic mice and B16/LLC1 syngeneic xenografts tumor models.

RESULTS

In this work, we identified 1166 up-regulated and 475 down-regulated differentially expressed genes in lung tumor tissues between KrasLA2 and miR-301a-/-; KrasLA2 mice. Immune response and cell cycle were major pathways involved in the protective role of miR-301a deletion in lung tumorigenesis. Overexpression of the miR-301a target, Runx3, was an early event identified in miR-301a-/-; KrasLA2 mice compared to WT-KrasLA2 mice. We found that miR-301a deletion enhanced CD8+ T cell accumulation and IFN-γ production in the tumor microenvironment and mediated antitumor immunity. Further studies revealed that miR-301a deficiency in the tumor microenvironment effectively reduced tumor metastasis by elevating Runx3 and recruiting CD8+ T cells, whereas miR-301a knockdown in tumor cells themselves restrained cell migration by elevating Runx3 expression.

CONCLUSIONS

Our findings further underscore that miR-301a facilitates tumor microenvironment antitumor immunity by Runx3 suppression in lung tumorigenesis.

RUNX family: Oncogenes or tumor suppressors (Review)

Runt-related transcription factor (RUNX) proteins belong to a transcription factors family known as master regulators of important embryonic developmental programs. In the last decade, the whole family has been implicated in the regulation of different oncogenic processes and signaling pathways associated with cancer. Furthermore, a suppressor tumor function has been also reported, suggesting the RUNX family serves key role in all different types of cancer. In this review, the known biological characteristics, specific regulatory abilities and experimental evidence of RUNX proteins will be analyzed to demonstrate their oncogenic potential and tumor suppressor abilities during oncogenic processes, suggesting their importance as biomarkers of cancer. Additionally, the importance of continuing with the molecular studies of RUNX proteins' and its dual functions in cancer will be underlined in order to apply it in the future development of specific diagnostic methods and therapies against different types of cancer.

INC280 inhibits Wnt/β-catenin and EMT signaling pathways and its induce apoptosis in diffuse gastric cancer positive for c-MET amplification

OBJECTIVE

Gastric cancer is more open related to genetic predisposition. In our RNA sequencing study on gastric cancer patients, Runt-related transcription factor-3 (RUNX3) expression was significantly down-regulated in gastric cancer. We showed that decreased levels of RUNX3 are significantly associated with c-MET (r = - 0.4216, P = 0.0130). In addition, c-MET expression is a candidate for targeted therapy in gastric cancer. Therefore, in the present study, the anti-cancer effects of the c-MET inhibitor on gastric cancer cells from positive or negative for c-MET amplification were evaluated.

RESULTS

INC280 treatment inhibits growth of a c-MET-amplified MKN45 (RUNX3-positive) and SNU620 (RUNX3-negative) diffuse type cells. Then, INC280 showed the highest inhibition and apoptotic rates with the lowest IC₅₀s in MKN45 cells but not in c-MET-reduced MKN28 (intestinal type) cells. We also showed that INC280 inhibits the WNT signaling pathway and SNAIL expression in MKN45 cells. The data indicate that INC280 could be used as therapeutic agents for the prevention or treatment of diffuse gastric cancer positive for c-MET amplification.

Interleukin 1 Up-regulates MicroRNA 135b to Promote Inflammation-Associated Gastric Carcinogenesis in Mice

BACKGROUND & AIMS

Gastritis is associated with development of stomach cancer, but little is known about changes in microRNA expression patterns during gastric inflammation. Specific changes in gene expression in epithelial cells are difficult to monitor because of the heterogeneity of the tissue. We investigated epithelial cell-specific changes in microRNA expression during gastric inflammation and gastritis-associated carcinogenesis in mice.

METHODS

We used laser microdissection to enrich epithelial cells from K19-C2mE transgenic mice, which spontaneously develop gastritis-associated hyperplasia, and Gan mice, which express activated prostaglandin E2 and Wnt in the gastric mucosa and develop gastric tumors. We measured expression of epithelial cell-enriched microRNAs and used bioinformatics analyses to integrate data from different systems to identify inflammation-associated microRNAs. We validated our findings in gastric tissues from mice and evaluated protein functions in gastric cell lines (SNU-719, SNU-601, SNU-638, AGS, and GIF-14) and knockout mice. Organoids were cultured from gastric corpus tissues of wild-type and miR-135b-knockout C57BL/6 mice. We measured levels of microRNAs in pairs of gastric tumors and nontumor mucosa from 28 patients in Japan.

RESULTS

We found microRNA 135b (miR-135B) to be the most overexpressed microRNA in gastric tissues from K19-C2mE and Gan mice: levels increased during the early stages of gastritis-associated carcinogenesis. Levels of miR-135B were also increased in gastric tumor tissues from gp130^F/F mice and patients compared with nontumor tissues. In gastric organoids and immortalized cell lines, expression of miR-135B was induced by interleukin 1 signaling. K19-C2mE mice with disruption of Mir-135b developed hyperplastic lesions that were 50% smaller than mice without Mir-135b disruption and had significant reductions in cell proliferation. Expression of miR-135B in gastric cancer cell lines increased their colony formation, migration, and sphere formation. We identified FOXN3 and RECK messenger RNAs (mRNAs) as targets of miR-135B; their knockdown reduced migration of gastric cancer cell lines. Levels of FOXN3 and RECK mRNAs correlated inversely with levels of miR-135B in human gastric tumors and in inflamed mucosa from K19-C2mE mice.

CONCLUSIONS

We found expression of miR-135B to be up-regulated by interleukin L1 signaling in gastric cancer cells and organoids. miR-135B promotes invasiveness and stem-cell features of gastric cancer cells in culture by reducing FOXN3 and RECK messenger RNAs. Levels of these messenger RNA targets, which encode tumor suppressor, are reduced in human gastric tumors.

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

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

The Ever-Evolving Concept of the Cancer Stem Cell in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, is the 4th most frequent cause of cancer-related death worldwide, primarily due to the inherent chemoresistant nature and metastatic capacity of this tumor. The latter is believed to be mainly due to the existence of a subpopulation of highly plastic “stem”-like cells within the tumor, known as cancer stem cells (CSCs), which have been shown to have unique metabolic, autophagic, invasive, and chemoresistance properties that allow them to continuously self-renew and escape chemo-therapeutic elimination. As such, current treatments for the majority of PDAC patients are not effective and do not significantly impact overall patient survival (<7 months) as they do not affect the pancreatic CSC (PaCSC) population. In this context, it is important to highlight the need to better understand the characteristics of the PaCSC population in order to develop new therapies to target these cells. In this review, we will provide the latest updates and knowledge on the inherent characteristics of PaCSCs, particularly their unique biological properties including chemoresistance, epithelial to mesenchymal transition, plasticity, metabolism and autophagy.

RUNX3 regulates renal cell carcinoma metastasis via targeting miR-6780a-5p/E-cadherin/EMT signaling axis

Runt-related transcription factor 3 (RUNX3) is a tumor suppressor in many human solid tumors. In this study, renal cell carcinoma (RCC) microarray analysis showed that the level of RUNX3 expression was lower in RCC tissue than in adjacent normal renal tissues, and was correlated with depth of invasion (pT stage) (P<0.001) and Tumor Node Metastasis (TNM) stage (P<0.001). RUNX3 expression was negatively correlated with poor 5-year overall and disease-free patient survival. RUNX3 suppressed RCC metastasis and invasion and increased levels of E-cadherin, an important marker of epithelial-mesenchymal transition, in vitro and in vivo. RUNX3 also inhibited microRNA-6780a-5p, which directly targeted the E-cadherin 3'untranslated region and decreased its expression. We confirmed that miR-6780a-5p mimics abrogated RUNX3-mediated E-cadherin upregulation and RCC metastasis/invasion inhibition. Thus, RUNX3 targeted the miR-6780a-5p/E-cadherin/EMT signaling axis to suppress renal carcinoma cell migration and invasion. This pathway illustrates a new RUNX3 function and provides potential targets for the treatment of RUNX3 mutant and loss-of-function RCC tumors. RUNX3 may also act as an effective prognostic indicator in RCC.

Roles of RUNX in Solid Tumors

All RUNX genes have been implicated in the development of solid tumors, but the role each RUNX gene plays in the different tumor types is complicated by multiple interactions with major signaling pathways and tumor heterogeneity. Moreover, for a given tissue type, the specific role of each RUNX protein is distinct at different stages of differentiation. A regulatory function for RUNX in tissue stem cells points sharply to a causal effect in tumorigenesis. Understanding how RUNX dysregulation in cancer impinges on normal biological processes is important for identifying the molecular mechanisms that lead to malignancy. It will also indicate whether restoration of proper RUNX function to redirect cell fate is a feasible treatment for cancer. With the recent advances in RUNX research, it is time to revisit the many mechanisms/pathways that RUNX engage to regulate cell fate and decide whether cells proliferate, differentiate or die.

Runx3 inhibits melanoma cell migration through regulation of cell shape change

The transcription factor Runx3 is a known tumor suppressor gene, and its expression is frequently lost in melanoma. However, the potential contribution of the loss of Runx3 expression to melanoma development and progression remains unclear. In this in vitro study, we demonstrated that ectopic Runx3 re-expression in B16-F10 melanoma cells changed the cell shape from elongated and branched to spread and unbranched, which enhanced stress fiber formation, increased the number of mature and fibrillar focal adhesions, and up-regulated fibronectin expression. In association with the cell shape change, the Runx3 re-expression in B16-F10 melanoma cells inhibited cell migration. Moreover, the phenotype of the Runx3 induced cell shape change was partially resembled when the melanoma cells were cultured on a fibronectin-coated coverslip, suggesting that fibronectin may mediate the Runx3 induced cell shape change of the melanoma cells. Taken together, our findings suggest that Runx3 may regulate cell shape to inhibit melanoma cell migration partly through enhancing stress fiber formation and ECM protein production. Our present study provides further evidence for the idea that cell shape change is potentially correlated with melanoma development and progression.

Site-specific Hypermethylation of RUNX3 Predicts Poor Prognosis in Gastric Cancer

BACKGROUND AND AIMS

Methylation status of RUNX3 remains largely unknown in gastric cancer (GC). The aim of this study was to prognostically evaluate the methylation level of CpG sites within RUNX3 promoter region in GC.

METHODS

Using pyrosequencing, we quantitatively explored the methylation status of 8 CpG sites within RUNX3 promoter region for 76 gastric cancer and 24 normal gastric tissues. We then analyzed the association between methylation level of each CpG site and clinicopathological characteristics and outcomes in the cohort.

RESULTS

Methylation of RUNX3 promoter was significantly higher in GC than normal subjects. Overall methylation level was closely associated with tumor invasion and TNM stage. Positive associations were found between hypermethylation of the following concerned sites and variables: site -1392, -1397, -1403, -1415 and tumor invasion, as well as TNM stage; site -1392 and lymph node metastasis along with number of lymph node metastases; site -1415 and cancer recurrence; site -1403, -1415 and cancer-related deaths. In multivariate analysis, tumor invasion was correlated with sites -1392 and -1397. Lymph node metastasis was associated with site -1392. Most importantly, methylation of site -1415 was associated with poor survival by using Cox survival regression.

CONCLUSION

Analysis of RUNX3 gene promoter by quantitative pyrosequencing suggested methylation status of RUNX3 is different in normal and tumor tissues. RUNX3 methylation level is associated with GC, especially the methylation at site -1415 contributes to the poor prognosis in GC. Thus, RUNX3 methylation may serve as a valuable diagnostic and prognostic biomarker in GC.

The EMT spectrum and therapeutic opportunities

Carcinomas are phenotypically arrayed along an epithelial–mesenchymal transition (EMT) spectrum, a developmental program currently exploited to understand the acquisition of drug resistance through a re‐routing of growth factor signaling. This review collates the current approaches employed in developing therapeutics against cancer‐associated EMT, and provides an assessment of their respective strengths and drawbacks. We reflect on the close relationship between EMT and chemoresistance against current targeted therapeutics, with a special focus on the epigenetic mechanisms that link these processes. This prompts the hypothesis that carcinoma‐associated EMT shares a common epigenetic pathway to cellular plasticity as somatic cell reprogramming during tissue repair and regeneration. Indeed, their striking resemblance suggests that EMT in carcinoma is a pathological adaptation of an intrinsic program of cellular plasticity that is crucial to tissue homeostasis. We thus propose a revised approach that targets the epigenetic mechanisms underlying pathogenic EMT to arrest cellular plasticity regardless of upstream cancer‐driving mutations.

RUNX3 regulates hepatocellular carcinoma cell metastasis via targeting miR-186/E-cadherin/EMT pathway

Runt-related transcription factor 3 (RUNX3) has been reported as a tumor suppressor in some kinds of cancers. In the present study, hepatocellular carcinoma (HCC) microarray analysis showed that RUNX3 expression was significantly lower in HCC tissues compared with that in adjacent non-tumor tissues, and was negatively associated with metastasis and TNM stage. RUNX3 was an independently prognostic factor for 5-year overall and disease-free patient survival. Mechanically, RUNX3 repressed metastasis and invasion of HCC, and increased E-cadherin expression. RUNX3 also repressed microRNA-186 to increase E-cadherin expression. We demonstrated that miR-186 mimics attenuated RUNX3-induced increase of E-cadherin and inhibition of metastasis and invasion. In conclusion, RUNX3 suppressed HCC cell migration and invasion by targeting the miR-186/E-cadherin/EMT pathway. RUNX3 may be recommended as an effective prognostic indicator and therapeutic target for patients with HCC.

Epithelial–mesenchymal transition and gastric cancer stem cell

Gastric cancer remains a big health problem in China. Gastric cancer cells contain a small subpopulation of cells that exhibit capabilities of differentiation and tumorigenicity. A putative explanation for ineffective therapy is the presence of cancer stem-like cells. Side population cells, which have cancer stem-like cells’ property, are characterized by the high efflux ability of Hoechst 33342 dye. Side population cells have been isolated from gastric cancer cell lines in previous studies. The epithelial–mesenchymal transition is very important in the invasion and metastasis of epithelial-derived cancers. More and more studies showed that gastric cancer stem-like cells possess high invasive ability and epithelial–mesenchymal transition property. A brief overview of the recent advancements in gastric cancer stem-like cells and epithelial–mesenchymal transition will be helpful for providing novel insight into gastric cancer treatment.

Wnt10B is critical for the progression of gastric cancer

The family of Wnt proteins have been implicated in embryogenesis by regulation of cell fate and pattern formation, and also in human carcinogenesis. Wnt10B was previously shown to be involved in breast cancer development. The present study assessed the association of Wnt10B expression in human gastric cancer tissue specimens with clinicopathological data from these patients. Wnt10B expression in the regulation of gastric cancer cell proliferation and migration capacity in vitro was then investigated. The data revealed that Wnt10B mRNA and protein were upregulated in gastric cancer tissue samples and the upregulated Wnt10B mRNA was associated with gastric cancer metastasizing to lymph nodes. Knockdown of Wnt10B expression reduced gastric cancer cell proliferation and migration, as well as expression of a cell proliferation marker Ki67. Knockdown of Wnt10B expression inhibited tumor cell epithelial-mesenchymal transition by upregulation of E-cadherin and downregulation of N-cadherin. In addition, Wnt10B knockdown also suppressed tumor cell stemness by downregulation of octamer-binding transcription factor 4 and Nanog expression. The present data indicated that Wnt10B expression performs an important role in gastric cancer progression in vitro. Therefore, targeting of Wnt10B expression or activity may be investigated as a possible strategy for the control of gastric cancer.

The Emerging Roles of RUNX Transcription Factors in Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is an evolutionary conserved morphogenetic program necessary for the shaping of the body plan during development. It is guided precisely by growth factor signaling and a dedicated network of specialised transcription factors. These are supported by other transcription factor families serving auxiliary functions during EMT, beyond their general roles as effectors of major signaling pathways. EMT transiently induces in epithelial cells mesenchymal properties, such as the loss of cell-cell adhesion and a gain in cell motility. Together, these newly acquired properties enable their migration to distant sites where they eventually give rise to adult epithelia. However, it is now recognized that EMT contributes to the pathogenesis of several human diseases, notably in tissue fibrosis and cancer metastasis. The RUNX family of transcription factors are important players in cell fate determination during development, where their spatio-temporal expression often overlaps with the occurrence of EMT. Furthermore, the dysregulation of RUNX expression and functions are increasingly linked to the aberrant induction of EMT in cancer. The present chapter reviews the current knowledge of this emerging field and the common themes of RUNX involvement during EMT, with the intention of fostering future research.

Runx3 and Cell Fate Decisions in Pancreas Cancer

The RUNX family transcription factors are critical regulators of development and frequently dysregulated in cancer. RUNX3, the least well characterized of the three family members, has been variously described as a tumor promoter or suppressor, sometimes with conflicting results and opinions in the same cancer and likely reflecting a complex role in oncogenesis. We recently identified RUNX3 expression as a crucial determinant of the predilection for pancreatic ductal adenocarcinoma (PDA) cells to proliferate locally or promulgate throughout the body. High RUNX3 expression induces the production and secretion of soluble factors that support metastatic niche construction and stimulates PDA cells to migrate and invade, while simultaneously suppressing proliferation through increased expression of cell cycle regulators such as CDKN1A/p21 ^WAF1/CIP1 . RUNX3 expression and function are coordinated by numerous transcriptional and post-translational inputs, and interactions with diverse cofactors influence whether the resulting RUNX3 complexes enact tumor suppressive or tumor promoting programs. Understanding these exquisitely context-dependent tumor cell behaviors has the potential to inform clinical decision-making including the most appropriate timing and sequencing of local vs. systemic therapies.

The clinicopathological significance of RUNX3 hypermethylation and mRNA expression in human breast cancer, a meta-analysis

Aberrant promoter methylation of RUNX3 has been reported in several tumors including human breast cancer (BC). However, the association between RUNX3 hypermethylation and incidence of BC remains elusive. In this study, a detailed literature search was performed in Medline and Google Scholar for related research publications. Analysis of pooled data were executed. Odds ratios with corresponding confidence intervals were determined and summarized, respectively. Finally, 13 studies were identified for the meta-analysis. Analysis of the pooled data showed that RUNX3 hypermethylation was significantly higher in both ductal carcinoma in situ and invasive ductal carcinoma (IDC) than in normal breast tissues. In addition, RUNX3 methylation was significantly higher in IDC than in benign tumor. However, RUNX3 methylation was not significantly higher in IDC than in ductal carcinoma in situ. We also determined that RUNX3 hypermethylation was significantly higher in ER positive BC than in ER negative BC. In addition, high RUNX3 mRNA expression was found to be correlated with better overall survival and relapse-free survival for all BC patients. Our results strongly support that RUNX3 hypermethylation may play an important role in BC incidence. RUNX3 methylation is a valuable early biomarker for the diagnosis of BC. Further large-scale studies will provide more insight into the role of RUNX3 hypermethylation in the carcinogenesis and clinical diagnosis of BC patients.

DDR1 enhances invasion and metastasis of gastric cancer via epithelial-mesenchymal transition

In this study, we investigated the effects of DDR1 on the invasion and metastasis in gastric cancer (GC) via epithelial-mesenchymal transition (EMT). Immunohistochemistry analysis was used to detect DDR1, E-cadherin, and Vimentin expression in GC tissues as well as DDR1 expression in GC cell lines and normal gastric epithelial cells. The relationship between DDR1 expression and EMT in GC cell lines was explored by down and upregulating DDR1 and examining corresponding changes in the expression of EMT-related proteins and in biological characteristics. Furthermore, a nude mice model with a transplantation tumor generating from stably transfected GC cells with DDR1 overexpression was established and performed to further reveal the effects of DDR1 expression on cellular morphology and growth of GC. Our results showed that DDR1 was highly expressed in GC tissues and cell lines compared with adjacent tissues and normal cell line, and its expression was significantly higher in GC having poor differentiation (p < 0.01), advanced depth of wall invasion (p = 0.020), lymph node metastasis (p = 0.0001), liver metastasis (p < 0.01), and high TNM stage (p < 0.01). Western blot analyses revealed that DDR1 overexpression resulted in a significant decrease in the expression of E-cadherin (p < 0.01) and an increase in the expression of Vimentin and Snail (p < 0.01), while knockdown of DDR1 led to opposite outcomes. We further demonstrated that DDR1 overexpression promoted GC cell proliferation (p < 0.05), migration (p < 0.01), and invasion (p < 0.01), and accelerated the growth (p < 0.05) as well as the microvessel formation (p < 0.01) of transplantation tumor in nude mice. Our study establishes that DDR1 enhances invasion and metastasis of gastric cancer via EMT.

Stem cell technology in breast cancer: current status and potential applications

Breast cancer, the leading cause of cancer among females, is supported by the presence of a rare subset of undifferentiated cells within the tumor, identified as breast cancer stem cells (BCSCs). BCSCs underlie the mechanisms of tumor initiation and sustenance and are implicated in the dissemination of the primary tumor to metastatic sites, as they have been found circulating in the blood of breast cancer patients. The discovery of BCSCs has generated a great amount of interest among the scientific community toward their isolation, molecular characterization, and therapeutic targeting. In this review, after summarizing the literature on molecular characterization of BCSCs and methodologies used for their isolation, we will focus on recent data supporting their molecular and functional heterogeneity. Additionally, following a synopsis of the latest approaches for BCSC targeting, we will specifically emphasize on the therapeutic use of naïve or engineered normal stem cells in the treatment of breast cancer and present contradictory findings challenging their safety.

Interaction between Wnt/β-catenin pathway and microRNAs regulates epithelial-mesenchymal transition in gastric cancer (Review)

Gastric cancer (GC) is the third primary cause of cancer-related mortality and one of the most common type of malignant diseases worldwide. Despite remarkable progress in multimodality therapy, advanced GC with high aggressiveness always ends in treatment failure. Epithelial-mesenchymal transition (EMT) has been widely recognized to be a key process associating with GC evolution, during which cancer cells go through phenotypic variations and acquire the capability of migration and invasion. Wnt/β-catenin pathway has established itself as an EMT regulative signaling due to its maintenance of epithelial integrity as well as tight adherens junctions while mutations of its components will lead to GC initiation and diffusion. The E-cadherin/β-catenin complex plays an important role in stabilizing β-catenin at cell membrane while disruption of this compound gives rise to nuclear translocation of β-catenin, which accounts for upregulation of EMT biomarkers and unfavorable prognosis. Additionally, several microRNAs positively or negatively modify EMT by reciprocally acting with certain target genes of Wnt/β-catenin pathway in GC. Thus, this review centers on the strong associations between Wnt/β-catenin pathway and microRNAs during alteration of EMT in GC, which may induce advantageous therapeutic strategies for human gastric cancer.