Loss of RUNX3 expression significantly affects the clinical outcome of gastric cancer patients and its restoration causes drastic suppression of tumor growth and metastasis

RUNX transcription factors are essential in maintaining epididymal epithelial differentiation

Apart from the androgen receptor, transcription factors (TFs) that are required for the development and formation of the different segments of the epididymis have remained unknown. We identified TF families expressed in the developing epididymides, of which many showed segment specificity. From these TFs, down-regulation of runt related transcription factors (RUNXs) 1 and 2 expression coincides with epithelial regression in Dicer1 cKO mice. Concomitant deletion of both Runx1 and Runx2 in a mouse epididymal epithelial cell line affected cell morphology, adhesion and mobility in vitro. Furthermore, lack of functional RUNXs severely disturbed the formation of 3D epididymal organoid-like structures. Transcriptomic analysis of the epididymal cell organoid-like structures indicated that RUNX1 and RUNX2 are involved in the regulation of MAPK signaling, NOTCH pathway activity, and EMT-related gene expression. This suggests that RUNXs are master regulators of several essential signaling pathways, and necessary for the maintenance of proper differentiation of the epididymal epithelium.

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.

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.

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

Background

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

Methods

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

Results

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

Conclusion

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

β-catenin S45F mutation results in apoptotic resistance

Wnt/β-catenin signaling is one of the key cascades regulating embryogenesis and tissue homeostasis; it has also been intimately associated with carcinogenesis. This pathway is deregulated in several tumors, including colorectal cancer, breast cancer, and desmoid tumors. It has been shown that CTNNB1 exon 3 mutations are associated with an aggressive phenotype in several of these tumor types and may be associated with therapeutic tolerance. Desmoid tumors typically have a stable genome with β-catenin mutations as a main feature, making these tumors an ideal model to study the changes associated with different types of β-catenin mutations. Here, we show that the apoptosis mechanism is deregulated in β-catenin S45F mutants, resulting in decreased induction of apoptosis in these cells. Our findings also demonstrate that RUNX3 plays a pivotal role in the inhibition of apoptosis found in the β-catenin S45F mutants. Restoration of RUNX3 overcomes this inhibition in the S45F mutants, highlighting it as a potential therapeutic target for malignancies harboring this specific CTNNB1 mutation. While the regulatory effect of RUNX3 in β-catenin is already known, our results suggest the possibility of a feedback loop involving these two genes, with the CTNNB1 S45F mutation downregulating expression of RUNX3, thus providing additional possible novel therapeutic targets for tumors having deregulated Wnt/β-catenin signaling induced by this mutation.

MicroRNA‑301a‑3p overexpression promotes cell invasion and proliferation by targeting runt‑related transcription factor 3 in prostate cancer

MicroRNAs (miRNAs) are known to serve a role in tumorigenic programs. The dysregulated expression of miR‑301a‑3p may affect the progression of various types of human cancer; however, the expression and the role of miR‑301a‑3p in prostate cancer are still unclear. The present study aimed to clarify the role and molecular mechanism of miR‑301a‑3p in prostate cancer. The results demonstrated that the expression of miR‑301a‑3p was significantly upregulated in human prostate cancer tissues and in several prostate cancer cell lines. In vitro overexpression of miR‑301a‑3p notably increased prostate cancer cell proliferation and invasion. Bioinformatics analysis revealed that runt‑related transcription factor 3 (RUNX3) may be a target of miR‑301a‑3p, which was confirmed by Dual‑luciferase reporter assay. Western blot analysis also demonstrated that miR‑301a‑3p regulated the protein expression levels of RUNX3. In addition, the results indicated that miR‑301a‑3p may regulate the Wnt signaling pathway, and rescue experiments indicated that RUNX3 contributed to the effects of miR‑301a‑3p on cell proliferation and invasion through Wnt signaling. In conclusion, these findings suggested that miR‑301a‑3p may promote prostate cancer cell invasion and proliferation by targeting RUNX3, and provided insight into understanding prostate cancer pathogenesis. miR‑301a‑3p may be a potential therapeutic candidate to treat prostate cancer.

RUNX3 inhibits glioma survival and invasion via suppression of the β-catenin/TCF-4 signaling pathway

INTRODUCTION

Runt-related transcription factor 3 (RUNX3) exerts a tumor suppressor gene associated with gastric and other cancers, including glioma. However, how its anti-tumor mechanism in functions glioma is unclear.

METHODS

We assayed expression of RUNX3 with a tissue microarray (TMA), frozen cancer tissues and malignant glioma cell lines using immunohistochemistry, qRT-PCR and Western bolt analysis. Cell proliferation, invasion, cell cycle distribution and apoptosis were also examined to confirm the effect of RUNX3 medicated malignant phenotype. TOP/FOP experiment was used to detect the β-catenin/Tcf-4 transcription activity by RUNX3.

RESULTS

Enforced RUNX3 expression inhibited proliferation and invasion, induced cell cycle arrest and promoted apoptosis in vitro and in vivo, Bim siRNA partically reversed the effect of RUNX3-induced apoptosis in LN229 and U87 cells, suggesting a dependent role of Bim-caspase pathway. Moreover, Mechanism investigations revealed that restoration of RUNX3 suppressed β-catenin/Tcf-4 transcription activity.

CONCLUSIONS

RUNX3 plays a pivotal role in glioma initiation and progression as a tumor suppressor via attenuation of Wnt signaling, highlighting it as a potential therapeutic target for glioma.

MicroRNA‑199b promotes cell proliferation and invasion in Wilms' tumour by directly targeting Runt‑related transcription factor 3

Emerging evidence has demonstrated that the deregulation of microRNAs (miRNAs) contributes to Wilms' tumour (WT) malignant progression. Therefore, identifying the essential miRNAs for WT onset and progression may be a promising therapeutic method for patients with this disease. Dysregulation of miRNA‑199b (miR‑199b) serves significant roles in various types of human cancer. However, its expression patterns, possible functions and associated mechanisms in WT are largely unknown. In the present study, the expression of miR‑199b in WT tissues was detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis. The biological functions of miR‑199b overexpression in WT cells were determined using Cell counting kit‑8 and Transwell invasion assays. The mechanisms underlying the action of miR‑199b in WT cells were also investigated using bioinformatics analysis, a luciferase reporter assay, RT‑qPCR and western blot analysis. It was revealed that miR‑199b expression was upregulated in WT tissues. In addition, the downregulation of miR‑199b attenuated the proliferation and invasion of WT cells. Runt‑related transcription factor 3 (RUNX3) was mechanistically predicted as a potential target of miR‑199b. Subsequent experiments demonstrated that RUNX3 was a direct target gene of miR‑199b in WT. In addition, the downregulation of RUNX3 in the WT tissues was inversely correlated with the miR‑199b expression level. The recovered RUNX3 expression counteracted the oncogenic roles of miR‑199b in WT cells. Therefore miR‑199b may serve as an oncogene in WT progression by directly targeting RUNX3, thereby suggesting that the miR‑199b/RUNX3 axis may be a promising therapeutic target for patients with WT.

Loss of RUNX3 is significantly associated with advanced tumor grade and stage in endometrial cancers

Loss of runt-related transcription factor 3 (RUNX3) has been reported in various cancers, and one of the mechanisms mediating loss of RUNX3 expression is DNA methylation. However, the role of RUNX3 expression and its DNA methylation status as prognostic factors in endometrial cancer remain unclear. In the present study, the expression and promoter methylation of RUNX3 was examined in endometrial cancer tissues and cell lines, as well as their association with endometrial cancer prognosis. Fifty-five endometrial cancer tissues and two endometrial cancer cell lines (HEC1-α and Ishikawa) were studied. RUNX3 expression and promoter methylation were examined using reverse transcription-polymerase chain reaction (RT-PCR), methylation specific PCR (MS-PCR), and immunohistochemical staining. The demethylating agent 5-aza-2′-deoxycytidine (ADC) was used to reverse the methylation of the RUNX3 promoter. Loss of RUNX3 expression was observed in 50.9% (27/53) of endometrial cancer tissues and in the HEC1-α cell line by immunohistochemistry and RT-PCR, respectively. Methylation of the RUNX3 promoter was observed in 62.2% (33/53) of endometrial cancer tissues, 12.5% (1/8) of normal endometrial tissues, and the HEC1-α cell line by MS-PCR. Tumor grade and stage were significantly correlated with loss of RUNX3 expression. The expression of RUNX3 was restored by treatment with ADC and resulted in growth inhibition in HEC1-α cells. The present results suggested that methylation may serve a critical role in the silencing of RUNX3 and loss of RUNX3 expression may serve as a prognostic marker in endometrial cancer.

Clinicopathological and prognostic significance of the RUNX3 expression in gastric cancer: a systematic review and meta-analysis

BACKGROUND

The relationship between expression of runt related transcription factor 3 (RUNX3) and clinicopathological parameters of the patients with gastric cancer (GC) is controversial.

METHODS

The studies were retrieved from those already published essay in PubMed, EMBASE, Wan Fang, CNKI (China National Knowledge Infrastructure), the Cochrane Library and Google Scholar. All statistical tests in this meta-analysis were performed using Stata 10.0 software (Stata Corp, College Station, TX). A P value less than 0.05 was considered statistically significant.

RESULTS

A total of nine studies involving 796 patients were included in final meta-analysis. The pooled data showed that expression of RUNX3 was significant correlated with tumor's differentiation (OR = 0.387; 95%CI: 0.237-0.633; P = 0.000), depth of invasion (OR = 0.443; 95%CI: 0.273-0.717; P = 0.001), lymph node metastasis (OR = 0.394; 95%CI: 0.259-0.598; P = 0.000), distant metastasis (OR = 0.403; 95%CI: 0.213-0.764; P = 0.005) and TNM stage (OR = 0.461; 95%CI, 0.322-0.659; P = 0.000) in GC. Expression of RUNX3 was significant correlated with good overall survival (OS) [1-year OS (OR = 2.735; 95%CI: 1.966-3.806; P = 0.000), 3-year OS (OR = 4.782; 95%CI: 3.634-6.292; P = 0.000), 5-year OS (OR = 5.191; 95%CI: 3.775-7.138; P = 0.000]. However, RUNX3 was not correlated with gender (OR = 1.409; 95%CI: 0.986-2.014; P = 0.060).

CONCLUSION

RUNX3 expression correlates with tumor's differentiation, depth of invasion, lymph node metastasis, distant metastasis, TNM stage and OS of GC patients.

miR106b regulates retinoblastoma Y79 cells through Runx3

MicroRNAs are increasingly recognized as important regulators of cancer. The aim of the present study was to investigate the role of miR-106b in the regulation of Y79 retinoblastoma. Y79 cells were transfected with antisense oligonucleotides (ASO) against miR-106b (ASO-miR-106b) or ASO-control. After transfection, the levels of miR-106b were monitored with real-time PCR (RT-PCR). The effects of ASO-miR-106b transfection on cell viability was evaluated by Cell Counting Kit-8 (CCK-8) analysis at 24, 48 and 72 h after transfection. Subsequently, the cells were stained with Annexin V-FITC and propidium iodide (PI) and subjected to flow cytometry to assess cell apoptosis. Transwell assay was used to analyze cell migration. Changes in Runt-related transcription factor 3 (Runx3) mRNA and proteins levels were also evaluated. miR-106b was downregulated by ASO-miR-106b at 48 and 72 h after transfection, accompanied by a decrease in cell viability and proliferation, as well as an increase in cell apoptosis. Transwell analysis indicated that cells treated with ASO-miR-106b exhibited significantly lower cell migratory abilities. The mRNA and protein level of Runx3 were upregulated after transfection. These results demonstrated that suppression of miR-106b inhibited Y79 cell proliferation and migration. The upregulation of Runx3 after miR-106b suppression ascertained that Runx3 is a tumor-suppressor in retinoblastoma and is a target of miR-106b.

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 role of microRNA-26a in human cancer progression and clinical application

MicroRNAs, a class of endogenous, small (18-25 nucleotides) noncoding RNAs, regulate gene expression by directly binding to the 3'-untranslated regions of target messenger RNAs. Evidence has shown that alteration of microRNAs is involved in cancer initial and progression. MicroRNA-26a is commonly dysregulated in diverse cancers and is involved in various biological processes, including proliferation, migration, invasion, angiogenesis, and metabolism by targeting multiple mRNAs. This review summarizes current research on the physiology and pathological functions of miR-26a and its applications for clinical therapy.

Clinicopathological significance and potential drug target of RUNX3 in non-small cell lung cancer: a meta-analysis

BACKGROUND

Emerging evidence indicates that RUNX3 is a candidate tumor suppressor in several types of human tumors, including non-small cell lung cancer (NSCLC). However, the correlation between RUNX3 hypermethylation and clinicopathological characteristics of NSCLC remains unclear. Here, we conducted a systematic review and meta-analysis to quantitatively evaluate the effects of RUNX3 hypermethylation on the incidence of NSCLC and clinicopathological characteristics.

METHODS

A detailed literature search was made using Medline, Embase and Web of Science for related research publications written in English. The methodological quality of the studies was evaluated. The data were extracted and assessed independently by two reviewers. Analysis of pooled data was performed. The odds ratio (OR) and hazard ratio were calculated and summarized.

RESULTS

Final analysis of 911 NSCLC patients from 13 eligible studies was performed. We observed that RUNX3 hypermethylation was significantly higher in NSCLC than in normal lung tissue; the pooled OR from seven studies including 361 NSCLC and 345 normal lung tissue (OR 7.08, confidence interval 4.12-12.17, P<0.00001). RUNX3 hypermethylation may also be associated with pathological types. The pooled OR was obtained from eleven studies including 271 squamous cell carcinoma and 389 adenocarcinoma (OR 0.41, confidence interval 0.19-0.89, P=0.02), which indicated that RUNX3 hypermethylation is significantly higher in adenocarcinoma that in squamous cell carcinoma. We did not find that RUNX3 hypermethylation was correlated with clinical stage or differentiated status. However, NSCLC patients with RUNX3 hypermethylation had a lower survival rate than those without RUNX3 hypermethylation.

CONCLUSION

The results of this meta-analysis suggest that RUNX3 hypermethylation is associated with an increased risk and worse survival in NSCLC. RUNX3 hypermethylation, which induces inactivation of the RUNX3 gene, plays an important role in lung carcinogenesis and clinical outcome.

Association of promoter methylation of RUNX3 gene with the development of esophageal cancer: a meta analysis

BACKGROUND

Runt-related transcription factor 3 (RUNX3) is a member of the runt-domain family of transcription factors. Emerging evidence indicates that RUNX3 is a tumor suppressor gene in several types of human cancers including esophageal cancer. However, the association between RUNX3 promoter methylation and esophageal cancer remains unclear. Here we conducted a systematic review and meta-analysis to quantitatively evaluate the effects of RUNX3 promoter methylation on the incidence of esophageal cancer.

METHODS

A detailed literature search was made on Medline, Pubmed and Web of Science for related research publications written in English and/or Chinese. Methodological quality of the studies was also evaluated. The data were extracted and assessed by two reviewers independently. Analysis of pooled data were performed, the odds ratios (OR) were calculated and summarized respectively.

RESULTS

Final analysis of 558 patients from 9 eligible studies was performed. The result showed that RUNX3 methylation was significantly higher in esophageal cancer than in normal squamous mucosa from the proximal resection margin or esophageal benign lesions (OR = 2.85, CI = 2.01-4.05, P<0.00001). The prevalence of lymph node involvement, tumor size (T1-T2 vs T3-T4) and histological grade was significantly greater in RUNX3-negative cases (RUNX3 unmethylated groups) than in RUNX3-positive cases (OR = 0.25, CI = 0.14-0.43, P<0.00001). RUNX3 methylation was significantly higher in esophageal adenocarcinoma (EAC) than Barrett's esophagus (OR = 0.35, CI = 0.20-0.59, P<0.0001). In addition, the pooled HR for overall survival (OS) showed that decreased RUNX3 expression was associated with worse survival in esophageal cancer (HR = 4.31, 95% CI = 2.57-7.37, P<0.00001).

CONCLUSIONS

The results of this meta-analysis suggest that RUNX3 methylation is associated with an increased risk, progression as well as worse survival in esophageal cancer. RUNX3 methylation, which induces the inactivation of RUNX3 gene, plays an important role in esophageal carcinogenesis.

Novel findings about management of gastric cancer: A summary from 10th IGCC

The Tenth International Gastric Cancer Congress (IGCC) was held in Verona, Italy, from June 19 to 22, 2013. The meeting enclosed various aspects of stomach tumor management, including both tightly clinical approaches, and topics more related to basic research. Moreover, an overview on gastrointestinal stromal tumors was provided too, although here not discussed. Here we will discuss some topics related to molecular biology of gastric cancer (GC), inherent to prognostic, diagnostic and therapeutic tools shown at the conference. Results about well known subjects, such as E-cadherin loss of expression/function, were presented. They revealed that other mutations of the gene were identified, showing a continuous research to improve diagnosis and prognosis of stomach tumor. Simultaneously, new possible molecular markers with an established role for other neoplasms, were discussed, such as mesothelin, stomatin-like protein 2 and Notch-1. Hence, a wide overview including both old and new diagnostic/prognostic tools was offered. Great attention was also dedicated to possible drugs to be used against GC. They included monoclonal antibodies, such as MS57-2.1, drugs used in other pathologies, such as maraviroc, and natural extracts from plants such as biflorin. We would like to contribute to summarize the most impressive studies presented at the IGCC, concerning novel findings about molecular biology of gastric cancer. Although further investigations will be necessary, it can be inferred that more and more tools were developed, so as to better face stomach neoplasms.

Clinical significance and association of RUNX3 hypermethylation frequency with colorectal cancer: a meta-analysis

Background

The RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor family and is closely involved in a variety of cellular processes including development, differentiation, participation in the regulation of p53-dependent DNA damage response and/or tumorigenesis. Emerging evidence indicates that RUNX3 is a candidate tumor suppressor in several types of human tumors including colorectal cancer (CRC). However, the correlation of RUNX3 inactivation with CRC remains unclear. In the study reported here, we conducted a systematic review and meta-analysis to quantitatively evaluate the effects of RUNX3 hypermethylation/expression on the incidence of CRC.

Methods

A detailed search of the literature was made using Medline^® and Web of Science for related research publications written in English. The methodological quality of the studies was also evaluated. The data were extracted and assessed by two reviewers independently. Analyses of the pooled data were performed. Odds ratios (ORs) and hazard ratios were calculated and summarized, respectively.

Results

A final analysis of 1,427 CRC patients from eleven eligible studies was performed. We observed that RUNX3 hypermethylation was significantly higher in CRC than in normal colorectal mucosa. The pooled OR from six studies comprising 289 CRC and 188 normal colorectal mucosa was OR =0.07 (confidence interval [CI] =0.03–0.18, P<0.00001). Aberrant RUNX3 hypermethylation/expression was significantly higher in advanced CRC than in early staged CRC (OR =0.54, CI =0.41–0.71, P<0.0001). Aberrant RUNX3 hypermethylation/expression was also significantly higher in microsatellite instability (MSI)-positive CRC than in MSI-negative CRC (OR =0.44, CI =0.3–0.66, P<0.0001). In addition, CRC patients with RUNX3 hypermethylation or lacking RUNX3 protein expression had a lower survival rate than those without RUNX3 hypermethylation or those who did not express RUNX3 protein.

Conclusion

The results of this meta-analysis suggest that RUNX3 hypermethylation is associated with an increased risk of CRC, increased risk of progression of CRC, and a poorer CRC survival rate. RUNX3 hypermethylation, which induces the inactivation of RUNX3 gene, plays an important role in colorectal carcinogenesis, high levels of MSI, as well as CRC progression and development.

The role of microRNAs in the regulation of apoptosis in lung cancer and its application in cancer treatment

Lung cancer remains to be one of the most common and serious types of cancer worldwide. While treatment is available, the survival rate of this cancer is still critically low due to late stage diagnosis and high frequency of drug resistance, thus highlighting the pressing need for a greater understanding of the molecular mechanisms involved in lung carcinogenesis. Studies in the past years have evidenced that microRNAs (miRNAs) are critical players in the regulation of various biological functions, including apoptosis, which is a process frequently evaded in cancer progression. Recently, miRNAs were demonstrated to possess proapoptotic or antiapoptotic abilities through the targeting of oncogenes or tumor suppressor genes. This review examines the involvement of miRNAs in the apoptotic process of lung cancer and will also touch on the promising evidence supporting the role of miRNAs in regulating sensitivity to anticancer treatment.

RUNX3 regulates vimentin expression via miR-30a during epithelial-mesenchymal transition in gastric cancer cells

Runt-related transcription factor 3 (RUNX3) is a putative tumour suppressor via regulating the expression of a series of target genes. Clinical studies demonstrated that loss of RUNX3 expression is associated with gastric cancer progression and poor prognosis, but the underlying mechanism is not entirely clear. Accumulating evidence shows that the epithelial–mesenchymal transition (EMT) plays an important role in cancer relapse and metastasis. Therefore, we addressed whether RUNX3 has a role in the EMT in gastric cancer. Knockdown of RUNX3 promoted cell invasion and increased the protein expression of the mesenchymal marker vimentin in human gastric cancer cells. Overexpression of RUNX3 suppressed cell invasion and decreased the protein expression of vimentin in the cells and inhibited gastric cancer cells colonization in nude mice. Furthermore, overexpression of RUNX3 increased the expression of microRNA-30a (miR-30a), and miR-30a directly targeted the 3′ untranslated region of vimentin and decreased its protein level. miR-30a inhibitor abrogated RUNX3-mediated inhibition of cell invasion and downregulation of vimentin. Thus, RUNX3 suppressed gastric cancer cell invasion and vimentin expression by activating miR-30a. In gastric cancer patients, levels of RUNX3 were positively correlated with miR-30a and negatively associated with the levels of vimentin. Collectively, our data suggest a novel molecular mechanism for the tumour suppressor activity of RUNX3. Effective therapy targeting the RUNX3 pathway may help control gastric cancer cell invasion and metastasis by inhibiting the EMT.

Clinicopathological significance and potential drug target of RUNX3 in breast cancer

BACKGROUND

Previous reports indicate that RUNX3 is a tumor suppressor in several types of human tumors, including breast cancer (BC). However, the correlation between RUNX3 hypermethylation and the incidence of BC remains unclear. In this study, we conducted a systematic review and meta-analysis aiming to comprehensively assess the potential role of RUNX3 hypermethylation in the pathogenesis of BC.

METHODS

A detailed literature search was made to identify studies for related research publications. Methodological quality of the studies was evaluated. Analysis of pooled data was performed. Odds ratio (OR) was calculated and summarized respectively.

RESULTS

Final analysis of 565 BC patients from eleven eligible studies was performed. The results showed that RUNX3 hypermethylation was significantly higher in BC than in normal breast tissue, the pooled OR from nine studies including 339 BC and 248 normal breast tissue (OR =24.12, 95% confidence interval [CI] =13.50-43.11, Z=10.75, P<0.00001). Further analysis also showed significantly increased OR of RUNX3 hypermethylation in estrogen receptor (ER)-positive than in ER-negative BC patients (OR =5.67, 95% CI =2.69-11.95, Z=4.57, P<0.00001). In addition, RUNX3 messenger RNA (mRNA) high expression was found to be correlated to better overall survival in 3,455 cases of BC patients that were followed up for 20 years (hazard ratio [HR] 0.79, P=8.8×10(-5)). Interestingly, RUNX3 mRNA overexpression was found to be correlated to better overall survival in only 668 cases of ER-negative patients (HR 0.72, P=0.01), but not in 1,767 cases of ER-positive patients (HR 0.87, P=0.13).

CONCLUSION

The results of this meta-analysis suggest that RUNX3 hypermethylation may be implicated in the pathogenesis of BC. Detection of RUNX3 mRNA may be a helpful and valuable biomarker for diagnosis of BC, especially in ER-negative BC. We also discussed the significance of RUNX3 as a potential drug target.

An inverse relationship between the expression of the gastric tumor suppressor RUNX3 and infection with Helicobacter pylori in gastric epithelial dysplasia

BACKGROUND/AIMS

This study was performed to determine the association between RUNX3 expression and Helicobacter pylori infection in premalignant gastric lesions.

METHODS

We examined 107 patients with gastric epithelial dysplasia who had undergone endoscopic mucosal resection or submucosal dissection. All tissue samples were evaluated by RUNX3 staining and subclassified by immunophenotype. H. pylori infection in dysplastic lesions and the normal surrounding tissue was examined by silver staining, and cagA status was assessed by polymerase chain reaction.

RESULTS

The loss of RUNX3 expression was observed in 62 cases (57.9%), and an association with H. pylori infection was found in 54 cases (50.5%). The infection rate with the cagA-positive H. pylori strain was 63.0%. In RUNX3-negative lesions, the rate of H. pylori infection (p=0.03) and the frequency of category 4 lesions (according to the revised Vienna classification) were high (p=0.02). In addition, the gastric mucin phenotype was predominant. In RUNX3-negative category 4 lesions, the rate of cagA-positive H. pylori infection rate was high but not significantly increased (p=0.08).

CONCLUSIONS

Infection with H. pylori is associated with inactivation of RUNX3 in early gastric carcinogenesis. This mechanism was prominent in gastric cancer with a gastric mucin phenotype.

Overexpressed miR-301a promotes cell proliferation and invasion by targeting RUNX3 in gastric cancer

BACKGROUND

MicroRNAs can promote or suppress the evolution of malignant behaviors by regulating multiple targets. We aimed to determine the expression of miR-301a recently screened in gastric cancer, to investigate the biological effects of miR-301a and to identify the specific miR-301a target gene.

METHODS

Quantitative real-time RT-PCR was used to test miR-301a expression. Functional effects were explored by a water-soluble tetrazolium salt assay, a colony formation assay in soft agar, a migration assay, an invasion assay and cytometry used to determine apoptosis and cell cycle. Nude mice were inoculated subcutaneously by retrovirus-mediated stably expressed SGC-7901 cells. The target gene was determined by bioinformatic algorithms, dual luciferase reporter assay and Western blot.

RESULTS

Firstly, we found that miR-301a was significantly upregulated both in cells and tissues of gastric cancer. The expression level of miR-301a was inversely correlated with tumor differentiation of gastric cancer tissues. Secondly, miR-301a promoted cell growth, soft agar clonogenicity, migration, invasion, and decreased cell apoptosis induced by cisplatin in vitro, while blockage of miR-301a reduced the percentage of G2/M phase cells via flow cytometry in gastric cancer cells. Ectopic expression of miR-301a enhanced the subcutaneous tumorigenesis in vivo. Finally, miR-301a directly downregulated RUNX3 expression post-transcriptionally in gastric cancer.

CONCLUSION

Our results demonstrate that miR-301a plays important roles in the development of gastric cancer.

Molecular biomarkers in esophageal, gastric, and colorectal adenocarcinoma

Cancers of the esophagus, stomach and colon contribute to a major health burden worldwide and over 20% of all cancer deaths. Biomarkers that should indicate pathogenic process and are measureable in an objective manner for these tumors are rare and not established in the clinical setting. In general biomarkers can be very useful for cancer management as they can improve clinical decision-making regarding diagnosis, surveillance, and therapy. Biomarkers can be different types of molecular entities (such as DNA, RNA or proteins), which can be detected, in different tissues or body fluids. However, more important is the type of biomarker itself, which allows diagnostic, prognostic or predictive analyses for different clinical problems. This review aims to systematically summarize the recent findings of genetic and epigenetic markers for gastrointestinal tumors within the last decade. While many biomarkers seem to be very promising, especially if used as panels, further development is urgently needed to address practical considerations of biomarkers in cancer treatment.

Effects of paeonol on intracellular calcium concentration and expression of RUNX3 in LoVo human colon cancer cells

Paeonol, a major phenolic component of the root bark of Paeonia moutan, is known to exhibit antitumor effects. However, the underlying mechanisms remain unknown. In the present study, the effects of paeonol on cell viability, intracellular calcium concentration and the expression of runt‑related transcription factor 3 (RUNX3) were analyzed in LoVo human colon cancer cells. Results revealed that paeonol markedly reduced LoVo cell viability in a time‑ and dose‑dependent manner. Flow cytometry assays demonstrated that paeonol blocked the cell cycle at the G1 to S transition and significantly induced apoptosis in LoVo cells. Intracellular calcium accumulation occurred following a 48 h treatment with paeonol. Furthermore, RUNX3 gene expression was increased in paeonol‑treated cells. These observations indicate that paeonol possesses antiproliferative properties and apoptosis‑inducing activity. One of the antitumor mechanisms of paeonol may be its apoptosis‑inducing activity through an increased intracellular calcium concentration and the upregulation of RUNX3 expression. Paeonol may be a promising antitumor agent for colon carcinoma treatment.

Antitumor activity of cell-permeable RUNX3 protein in gastric cancer cells

PURPOSE

Gastric cancer is a leading cause of cancer death worldwide. Limited therapeutic options highlight the need to understand the molecular changes responsible for the disease and to develop therapies based on this understanding. The goal of this study was to develop cell-permeable (CP-) forms of the RUNT-related transcription factor 3, RUNX3-a candidate tumor suppressor implicated in gastric and other epithelial cancers-to study the therapeutic potential of RUNX3 in the treatment of gastric cancer.

EXPERIMENTAL DESIGN

We developed novel macromolecule transduction domains (MTD) which were tested for the ability to promote protein uptake by mammalian cells and tissues and used to deliver of biologically active RUNX3 into human gastric cancer cells. The therapeutic potential CP-RUNX3 was tested in the NCI-N87 human tumor xenograft animal model.

RESULTS

RUNX3 fusion proteins, HM(57)R and HM(85)R, containing hydrophobic MTDs enter gastric cancer cells and suppress cell phenotypes (e.g., cell-cycle progression, wounded monolayer healing, and survival) and induce changes in biomarker expression (e.g., p21(Waf1) and VEGF) consistent with previously described effects of RUNX3 on TGF-β signaling. CP-RUNX3 also suppressed the growth of subcutaneous human gastric tumor xenografts. The therapeutic response was comparable with studies augmenting RUNX3 gene expression in tumor cell lines; however, the protein was most active when administered locally, rather than systemically (i.e., intravenously).

CONCLUSIONS

These results provide further evidence that RUNX3 can function as a tumor suppressor and suggest that practical methods to augment RUNX3 function could be useful in treating of some types of gastric cancer.

Advances in gastric cancer prevention

Gastric cancer is a multifactorial neoplastic pathology numbering among its causes both environmental and genetic predisposing factors. It is mainly diffused in South America and South-East Asia, where it shows the highest morbility percentages and it is relatively scarcely diffused in Western countries and North America. Although molecular mechanisms leading to gastric cancer development are only partially known, three main causes are well characterized: Helicobacter pylori (H. pylori) infection, diet rich in salted and/or smoked food and red meat, and epithelial cadherin (E-cadherin) mutations. Unhealthy diet and H. pylori infection are able to induce in stomach cancer cells genotypic and phenotypic transformation, but their effects may be crossed by a diet rich in vegetables and fresh fruits. Various authors have recently focused their attention on the importance of a well balanced diet, suggesting a necessary dietary education starting from childhood. A constant surveillance will be necessary in people carrying E-cadherin mutations, since they are highly prone in developing gastric cancer, also within the inner stomach layers. Above all in the United States, several carriers decided to undergo a gastrectomy, preferring changing their lifestyle than living with the awareness of the development of a possible gastric cancer. This kind of choice is strictly personal, hence a decision cannot be suggested within the clinical management. Here we summarize the key points of gastric cancer prevention analyzing possible strategies referred to the different predisposing factors. We will discuss about the effects of diet, H. pylori infection and E-cadherin mutations and how each of them can be handled.

MicroRNA-26a regulates tumorigenic properties of EZH2 in human lung carcinoma cells

MicroRNAs (miRNAs) are a class of 21-23 nucleotide RNA molecules that play critical roles in the regulation of various cancers, including human lung cancer. Among them, miR-26a has been identified as a tumor-related regulator in several cancers, but its pathophysiologic properties and correlation with the development of human lung cancer remain unclear. In this study, it was determined that miR-26a expression is clearly down-regulated in human lung cancer tissues relative to normal tissues. Meanwhile, the overexpression of miR-26a in the A549 human lung cancer cell line dramatically inhibited cell proliferation, blocked G1/S phase transition, induced apoptosis, and inhibited cell metastasis and invasion in vitro. In contrast, a miR-26a inhibitor was used to transfect A549 cells, and the inhibition of endogenous miR-26a promoted cell metastasis and invasion. In addition, miR-26a expression inhibited the expression of enhancer of zeste homolog 2 (EZH2) and transactivated downstream target genes, including disabled homolog 2 (Drosophila) interacting protein gene (DAB2IP) and human Runt-related transcription factor 3 (RUNX3), which suggests that EZH2 is a potential target of miR-26a as previously reported. In conclusion, miR-26a plays an important role as an anti-oncogene in the molecular mechanism of human lung cancer and could potentially be used for the treatment of lung cancer.

RUNX3 is involved in caspase-3-dependent apoptosis induced by a combination of 5-aza-CdR and TSA in leukaemia cell lines

PURPOSE

Epigenetic therapy has had a significant impact on the management of haematologic malignancies. The aim of this study was to assess whether 5-aza-CdR and TSA inhibit the growth of leukaemia cells and induce caspase-3-dependent apoptosis by upregulating RUNX3 expression.

METHODS

K562 and Reh cells were treated with 5-aza-CdR, TSA or both compounds. RT-PCR and Western blot analyses were used to examine the expression of RUNX3 at the mRNA and protein levels, respectively. Immunofluorescence microscopy was used to detect the cellular location of RUNX3. Additionally, after K562 cells were transfected with RUNX3, apoptosis and proliferation were studied using Annexin V staining and MTT assays.

RESULTS

The expression of RUNX3 in leukaemia cell lines was markedly less than that in the controls. Demethylating drug 5-aza-CdR could induce RUNX3 expression, but the combination of TSA and 5-aza-CdR had a greater effect than did treatment with a single compound. The combination of 5-aza-CdR and TSA induced the translocation of RUNX3 from the cytoplasm into the nucleus. TSA enhanced apoptosis induced by 5-aza-CdR, and Annexin V and Hoechst 33258 staining showed that the combination induced apoptosis but not necrosis. Furthermore, apoptosis was dependent on the caspase-3 pathway. RUNX3 overexpression in K562 cells led to growth inhibition and apoptosis and potentiated the effects of 5-aza-CdR induction.

CONCLUSION

RUNX3 plays an important role in leukaemia cellular functions, and the induction of RUNX3-mediated effects may contribute to the therapeutic value of combination TSA and 5-aza-CdR treatment.

Runx3 expression in lymph nodes with metastasis is associated with the outcome of gastric cancer patients

Accumulating evidence shows that runt-related transcription factor 3 (Runx3) is a putative tumor suppressor in various types of cancer, the lower levels of which are associated with a less favorable cancer outcome. However, these studies were restricted to primary cancer lesions. Lymph node metastasis (LNM) is a significant factor in determining the prognosis of patients with gastric cancer and is a frequent target of chemotherapy. In the present study, we investigated the expression of Runx3 in the lymph nodes (LNs) of stomach carcinoma and the association of Runx3 expression with the prognosis of patients. The expression of Runx3 in LNs with and without metastasis was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The positive rate of Runx3 mRNA in LNM specimens was significantly lower (28.4%, 21 out of 74) compared to that of the non-metastatic samples (33.3%, 9 out of 27, P<0.05). Similar findings were obtained by Western blotting. Univariate analysis revealed that the loss of Runx3 expression in LNs was not only associated with poor clinicopathological factors, such as LNM, distant organ metastasis, later clinicopathological stages and deep infiltration, but also with a lower 5-year survival rate and poorer prognosis. These results strongly suggest a potential diagnostic value of Runx3 expression in LNs and multiple pathways contributing to the outcome of patients with gastric cancer.

Association between RUNX3 promoter methylation and gastric cancer: a meta-analysis

Background

Runt-related transcription factor 3 (RUNX3) is a member of the runt-domain family of transcription factors and has been reported to be a candidate tumor suppressor in gastric cancer. However, the association between RUNX3 promoter methylation and gastric cancer remains unclear.

Methods

We systematically reviewed studies of RUNX3 promoter methylation and gastric cancer published in English or Chinese from January 2000 to January 2011, and quantified the association between RUNX3 promoter methylation and gastric cancer using meta-analysis methods.

Results

A total of 1740 samples in 974 participants from seventeen studies were included in the meta-analysis. A significant association was observed between RUNX3 promoter methylation and gastric cancer, with an aggregated odds ratio (OR) of 5.63 (95%CI 3.15, 10.07). There was obvious heterogeneity among studies. Subgroup analyses (including by tissue origin, country and age), meta-regression were performed to determine the source of the heterogeneity. Meta-regression showed that the trend in ORs was inversely correlated with age. No publication bias was detected. The ORs for RUNX3 methylation in well-differentiated vs undifferentiated gastric cancers, and in intestinal-type vs diffuse-type carcinomas were 0.59 (95%CI: 0.30, 1.16) and 2.62 (95%CI: 1.33, 5.14), respectively. There were no significant differences in RUNX3 methylation in cancer tissues in relation to age, gender, TNM stage, invasion of tumors into blood vessel or lymphatic ducts, or tumor stage.

Conclusions

This meta-analysis identified a strong association between methylation of the RUNX3 promoter and gastric cancer, confirming the role of RUNX3 as a tumor suppressor gene.

Critical regions and spreading of runt-related transcription factor-3 C-phosphate-G (CpG) island methylation in human salivary gland adenoid cystic carcinoma

We investigated the spreading pattern of runt-related transcription factor-3 (RUNX3) C-phosphate-G (CpG) island (3478 base pairs) methylation in salivary gland adenoid cystic carcinoma. The methylation status of multiple regions within the runt-related transcription factor-3 promoter CpG island (3478 base pairs) was detected by real-time methylation-specific polymerase chain reaction, and the runt-related transcription factor-3 protein was detected with a Western blot in 19 salivary gland adenoid cystic carcinoma samples and the corresponding nonneoplastic salivary glands. The risk ratio between runt-related transcription factor-3 CpG island methylation and salivary gland adenoid cystic carcinoma progression was analyzed by the logistic analysis of variance model. A possible association between runt-related transcription factor-3 methylation, clinicopathologic parameters, and runt-related transcription factor-3 protein was analyzed. Hypermethylation initially occurs the most at the 5' region of runt-related transcription factor-3 CpG island before spreading to the transcription start site. The extent of methylation was found to be the highest in region nos. 1 and 2 among the successive 10 regions, which extend from the 5' region to the transcription start site within the runt-related transcription factor-3 CpG island. The extent of methylation is lowest at the transcription start site, both in salivary gland adenoid cystic carcinoma and in normal salivary glands. No methylation in the transcription start site was found in normal salivary glands. Logistic analysis of variance model indicates that the transcription start site within the runt-related transcription factor-3 promoter CpG island is critical for gene silencing. Western blots revealed that levels of the runt-related transcription factor-3 protein in adenoid cystic carcinoma samples are significantly lower than those in normal salivary glands (P < .001). Methylation of the runt-related transcription factor-3 CpG island spreads the most from 5' region to the transcription start site in adenoid cystic carcinoma tissues, and the transcription start site may be a critical region for the runt-related transcription factor-3 methylation. The spreading pattern of the runt-related transcription factor-3 methylation may play an a role in the progression of adenoid cystic carcinoma.

Loss of runt-related transcription factor 3 causes development and progression of hepatocellular carcinoma

Runt-related transcription factor 3 (RUNX3) is reported as a tumor suppressor gene for gastric cancer, and may be important in the development of hepatocellular carcinoma (HCC). RUNX3 expression is frequently lost or decreased by hemizygous deletion or hypermethylation of its promoter lesion in HCC. The significance of decreased expression of RUNX3 in HCC has not been fully elucidated, but is likely related to dysfunction of cell cycle regulation, decrement of apoptosis, enhancement of angiogenesis, and development of epithelial-mesenchymal transition. RUNX3 is a promising candidate as a tumor suppressor gene for HCC.

Molecular mechanisms of metastasis

The mechanism of metastasis is a complex set of events that build upon each other to achieve successful growth in organ sites beyond the primary tumor. The cumulative events for metastasis of different cancers have both common and specific cancer specific events. This review discusses several key factors in different cancers that are responsible in metastasis, which includes epigenetic regulation of tumor suppressor genes, functional activity of tumor-related chemokine receptors, and circulating tumor cells.

Oncogenic role of RUNX3 in head and neck cancer

Cumulative evidences show that Runt-related transcription factor 3 (RUNX3) has a tumor suppressive role in various cancers. In particular, RUNX3 appears to be an important component of the transforming growth factor-β (TGF-β)-induced tumor suppression pathway. Contrary to reports on this tumor suppressive role of RUNX3, RUNX3 can also function as an oncogene when overexpressed. Recently, we found that RUNX3 overexpression was frequently observed and was well correlated with malignant behaviors in head and neck cancer, which is one of the most common types of human cancer. Moreover, it has been revealed that RUNX3 overexpression promoted cell growth and inhibited apoptosis in head and neck cancer cells. This review introduces the oncogenic role of RUNX3 in certain types of cancer including head and neck cancer.

New insights into the inactivation of gastric tumor suppressor RUNX3: the role of H. pylori infection

Runt-related transcription factor 3, or RUNX3, is a tumor suppressor in gastric cancer. Inactivation of RUNX3 is causally associated with the genesis of gastric cancer, since RUNX3 is frequently inactivated in gastric cancers by hemizygous deletion, hypermethylation of its promoter, or protein mislocalization. Infection with Helicobacter pylori is the strongest risk factor for the development of gastric cancer. Recent studies have indicated that H. pylori infection plays an important role in the inactivation of RUNX3, and that this inactivation contributes to the pathogenesis of H. pylori. Here we summarize these recent advances and discuss their significances in understanding the initiation and development of gastric cancer.

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer. In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Prognostic significance of RUNX3 expression in human melanoma

BACKGROUND

RUNX3 is a tumor suppressor that plays important roles in cell proliferation, apoptosis, and metastasis. The authors investigated the role of RUNX3 in melanoma pathogenesis and analyzed the prognostic impact of RUNX3 expression in a large series of melanoma patients.

METHODS

Two sets of tissue microarrays were constructed, including 440 cases of melanomas (202 for the training set and 238 for the validation set) and 88 cases of nevi (25 normal nevi and 63 dysplastic nevi). RUNX3 expression was evaluated by immunohistochemistry.

RESULTS

Positive RUNX3 expression was observed in 56%, 54%, 33%, and 24% of the biopsies in normal nevi, dysplastic nevi, primary melanoma, and melanoma metastases, respectively. Significant differences for positive nuclear RUNX3 staining were observed between dysplastic nevi and primary melanomas (P = .002, chi-square test), between dysplastic nevi and melanoma metastases (P < .001, chi-square test), and between primary melanoma and melanoma metastases (P = .045, chi-square test). Loss of RUNX3 expression was correlated with a worse 5-year survival of melanoma patients in both training and validation sets. Furthermore, loss of RUNX3 expression was also correlated with a poor 5-year disease-specific survival in primary melanoma (P = .001) and metastatic melanoma patients (P = .008). Multivariate Cox regression analysis revealed that positive RUNX3 expression is an independent prognostic factor to predict melanoma patient outcome.

CONCLUSIONS

Our findings indicate that RUNX3 plays an important role in melanoma pathogenesis and may serve as a promising prognostic marker for melanoma.

RUNX3 methylation and expression associated with advanced precancerous gastric lesions in a Chinese population

Runt-related transcription factor 3 (RUNX3) is a tumor suppressor of gastric cancer. Our study aimed to investigate the correlation of RUNX3 methylation, expression and the risk of advanced gastric lesions, based on a high-risk population in Linqu County, Shandong Province, China. Methylation status of RUNX3 was determined by methylation-specific polymerase chain reaction, and expression was detected by immunohistochemical analysis in 1113 subjects with different gastric lesions. Results showed that the frequency of RUNX3 methylation was significantly increased in subjects with advanced gastric lesions. The odds ratios (ORs) were 2.09 [95% confidence interval (CI): 1.49-2.94] for intestinal metaplasia (IM), 3.22 (95% CI: 2.33-4.47) for indefinite dysplasia (Ind DYS) and 2.03 (95% CI: 1.23-3.37) for dysplasia (DYS) compared with superficial gastritis/chronic atrophic gastritis. Stratified analysis indicated that the frequency of RUNX3 methylation was higher in subjects with Helicobacter pylori infection (OR, 2.74; 95% CI: 2.00-3.76). Moreover, there was a reverse grade-response relationship between the level of RUNX3 expression and risk of gastric lesions. Among subjects with mild, moderate or heavy expression, the risk was decreased by 41, 59 or 80% for IM (P(trend) < 0.0001); 40, 64 or 74% for Ind DYS (P(trend) < 0.0001) and 28, 59 or 51% for DYS (P(trend) = 0.045), respectively. Furthermore, RUNX3 expression was negatively associated with increased frequency of RUNX3 methylation (OR, 0.76; 95% CI: 0.59-0.98). These findings suggest that RUNX3 may play important roles in the development of advanced gastric lesions.

Helicobacter pylori CagA targets gastric tumor suppressor RUNX3 for proteasome-mediated degradation

Chronic infection with cagA-positive Helicobacter pylori is the strongest risk factor for the development of gastric adenocarcinoma. The cagA gene product CagA is injected into gastric epithelial cells and disturbs cellular functions by physically interacting with and deregulating a variety of cellular signaling molecules. RUNX3 is a tumor suppressor in many tissues, and it is frequently inactivated in gastric cancer. In this study, we show that H. pylori infection inactivates the gastric tumor suppressor RUNX3 in a CagA-dependent manner. CagA directly associates with RUNX3 through a specific recognition of the PY motif of RUNX3 by a WW domain of CagA. Deletion of the WW domains of CagA or mutation of the PY motif in RUNX3 abolishes the ability of CagA to induce the ubiquitination and degradation of RUNX3, thereby extinguishing its ability to inhibit the transcriptional activation of RUNX3. Our studies identify RUNX3 as a novel cellular target of H. pylori CagA and also reveal a mechanism by which CagA functions as an oncoprotein by blocking the activity of gastric tumor suppressor RUNX3.

H. pylori-Eradication Therapy Increases RUNX3 Expression in the Glandular Epithelial Cells in Enlarged-Fold Gastritis

Helicobacter pylori (HP)-eradication therapy increases Runt domain transcription factor 3 (RUNX3) expression in the glandular epithelial cells in enlarged-fold gastritis. The aim of this study is to evaluate expression of the RUNX3 protein, the product of a gastric tumor suppression gene, and mutagenic oxidative stress in human gastric mucosal specimens obtained from patients with HP-induced enlarged-fold gastritis. Methods. RUNX3 expression was immunohistochemically scored and the degree of the mucosal oxidative stress was directly measured by the chemiluminescense (ChL) assay in the biopsy specimens. Results. RUNX3 expression was detected in the gastric epithelial cells. HP-eradication significantly increased RUNX3 expression in the glandular epithelium of the corpus, however, no change was observed in those of the antrum. A fourfold higher mucosal ChL value was observed in the corpus as compared with that in the antrum. HP-eradication significantly decreased the mucosal ChL values in both portions of the stomach to nearly undetectable levels. Conclusion. The glandular epithelium is exposed to a high level of carcinogenic oxidative stress and shows low levels of expression of the tumor suppressive molecule, RUNX3; however, this expression was restored after HP-eradication, suggesting the high risk of carcinogenesis associated with HP-induced enlarged-fold gastritis of the corpus.

Hypermethylation downregulates Runx3 gene expression and its restoration suppresses gastric epithelial cell growth by inducing p27 and caspase3 in human gastric cancer

BACKGROUND AND AIMS

Runx family transcription factors are integral components of transforming growth factor-beta signaling pathways and have been implicated in cell cycle regulation, differentiation, apoptosis, and malignant transformation. The silencing of tumor suppressor genes by aberrant hypermethylation occurs frequently in human cancer. It has been noted previously that Runx3 is regarded as an important tumor suppressor gene.

METHODS

Reverse transcription polymerase chain reaction was used to measure Runx3 and the DNA methyltransferase 1 (Dnmt1) messenger RNA (mRNA) expression level of paired samples of primary gastric cancer and corresponding non-cancerous gastric mucosae, which were obtained from surgically resected specimens of 70 patients. Western blot was used to detect the expression of Runx3 at protein levels. The promoter methylation status was measured by using methylation-specific polymerase chain reaction. We used Annexin V-FITC/PI assay to detect cell apoptosis, and the cell cycle was also analyzed. In order to examine the cell cycle and/or apoptosis, we determined p27 and caspase 3 expression by immunohistological analysis.

RESULTS

Our results demonstrate a loss or substantial decrease of Runx3 expression in 70 cases of gastric tumors as compared with that in normal gastric mucosa (0.5749 +/- 0.3580 vs 1.7252 +/- 0.4085, P < 0.05). The protein levels of the Runx3 gene were significantly lower in gastric cancers than those in adjacent normal tissues. The hypermethylation of Runx3 was involved in 50% (28/56) of gastric cancer tissues, which had reduced Runx3 mRNA expression. The differences of the Dnmt1 mRNA level were significant between the methylated and unmethylated Runx3 cancerous groups. Runx3 methylation was significantly correlated with increased Dnmt1 (r = 0.64, P < 0.01). Enforced restoration of Runx3 expression led to the induction of cell apoptosis and upregulation of p27 and caspase3 expression in vitro.

CONCLUSIONS

Our results suggest that a decrease of Runx3 expression by DNA hypermethylation is frequently associated with the evolution of gastric cancer. Runx3 was an independent prognostic factor and a potential therapeutic target for gastric cancer.