Yin Yang 1 contributes to gastric carcinogenesis and its nuclear expression correlates with shorter survival in patients with early stage gastric adenocarcinoma

DEAD/H-box helicase 11 is transcriptionally activated by Yin Yang-1 and accelerates oral squamous cell carcinoma progression

Oral squamous cell carcinoma (OSCC) is the most common oral malignancy. DEAD/H-box helicase 11 (DDX11), a DNA helicase, has been implicated in the progression of several cancers. Yet, the precise function of DDX11 in OSCC is poorly understood. The DDX11 expression in OSCC cells and normal oral keratinocytes was evaluated in the Gene Expression Omnibus database (GSE146483 and GSE31853). SCC-4 and CAL-27 cells expressing doxycycline-inducible DDX11 or DDX11 shRNA were generated by lentiviral infection. The role of DDX11 in OSCC cells was determined by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, colony formation assay, flow cytometry assay, TUNEL staining, and western blot. The effects of DDX11 on tumor growth were explored in a xenograft nude mouse model. The relationship between DDX11 and transcription factor Yin Yang-1 (YY1) was researched using the dual luciferase report assay and chromatin immunoprecipitation assay. DDX11 expression was significantly upregulated in OSCC cells. Knockdown of DDX11 inhibited cell proliferation, induced cell cycle arrest, and suppressed PI3K-AKT pathway, while DDX11 overexpression showed opposite effects. The number of apoptotic cells was increased in DDX11 silenced cells. DDX11 upregulation or knockdown accelerated or suppressed tumor growth in vivo, respectively. Moreover, the YY1 bound and activated the DDX11 promoter, resulting in increasing DDX11 expression. Forced expression DDX11 reversed the anticancer effects of YY1 silencing on OSCC cells. DDX11 has tumor-promoting function in OSCC and is transcriptionally regulated by YY1, indicating that DDX11 may serve as a potential target for the OSCC treatment.

Embryonic microenvironment suppresses YY1 and YY1-related genes in prostate cancer stem cells

Yin yang 1 (YY1), a transcription factor, plays crucial roles in cell fate specification, differentiation, and pluripotency during embryonic development. It is also involved in tumorigenesis, drug resistance, metastasis, and relapse caused by cancer stem cells (CSCs), particularly in prostate cancer (PCa). Targeting YY1 could potentially eliminate prostate CSCs (PCSCs) and provide novel therapeutic approaches. PCa tissues often exhibit elevated YY1 expression levels, especially in high-grade cases. Notably, high-grade PCa tissues from 58 PCa patients and CD133high/CD44high PCSCs isolated from DU145 PCa cell line by FACS both showed significantly increased YY1 expression as observed through immunofluorescence staining, respectively. To investigate the embryonic microenvironment impact on YY1 expression in CSC populations, firstly PCSCs were microinjected into the inner cell mass of blastocysts and then PCSCs were co-cultured with blastocysts. Next Generation Sequencing was used to analyze alterations in YY1 and related gene expressions. Interestingly, exposure to the embryonic microenvironment significantly reduced the expressions of YY1, YY2, and other relevant genes in PCSCs. These findings emphasize the tumor-suppressing effects of the embryonic environment by downregulating YY1 and YY1-related genes in PCSCs, thus providing promising strategies for PCa therapy. Through elucidating the mechanisms involved in embryonic reprogramming and its effects on YY1 expression, this research offers opportunities for further investigation into focused therapies directed against PCSCs, therefore enhancing the outcomes of PCa therapy. As a result, PCa tumors may benefit from YY1 and associated genes as a novel therapeutic target.

A Novel ceRNET Relying on the lncRNA JPX, miR-378a-3p, and Its mRNA Targets in Lung Cancer

Lung cancer is the leading cause of cancer-related death worldwide. Non-coding RNAs are emerging as critical players for the onset and progression of cancer. Analyses of three different datasets revealed that the lncRNA JPX was overexpressed in adenocarcinoma tissues in comparison to normal lungs, as expected for an oncogene. Intriguingly, the predicted binding miR-378a-3p showed a significant inverse correlation with JPX expression. The lncRNA/miRNA physical interaction was validated by reporter vectors. Then, the oncogenic activity of JPX, the tumor-suppressive role of miR-378a-3p, and the contribution of their functional interaction to cancer hallmarks were demonstrated using assays for cell proliferation, migration, invasion, and 3D-spheroid formation. Finally, molecular circuits were investigated by boosting the expression of both JPX and miR-378a-3p, singularly and in combination, demonstrating that JPX counteracted miR-378a-3p silencing activity toward its oncogenic targets GLUT1, NRP1, YY1, and Wnt5a. Overall, the data unveil a novel ceRNET (competing endogenous RNA network), wherein JPX acts as a ceRNA by binding to miR-378a-3p, thus reducing the miRNA silencing activity toward its downstream targets, and eliciting oncogenic pathways driving lung cancer. The knowledge of the network may pave the way to develop new diagnostic panels, and innovative RNA-targeted and RNA-based therapeutic strategies.

Yin Yang 1 promotes the neuroendocrine differentiation of prostate cancer cells via the non-canonical WNT pathway (FYN/STAT3)

BACKGROUND

A growing number of studies have shown that Yin Yang 1 (YY1) promotes the development of multiple tumours. The purpose of the current study was to determine the mechanism by which YY1 mediates neuroendocrine differentiation of prostate cancer (NEPC) cells undergoing cellular plasticity.

METHODS

Using the Cancer Genome Atlas and Gene Expression Omnibus (GEO) databases, we bioinformatically analyzed YY1 expression in prostate cancer (PCa). Aberrant YY1 expression was validated in different PCa tissues and cell lines via quantitative reverse transcription polymerase chain reaction, western blotting, and immunohistochemistry. In vivo and in vitro functional assays verified the oncogenicity of YY1 in PCa. Further functional assays showed that ectopic expression of YY1 promoted cellular plasticity in PCa cells via epithelial-mesenchymal transition induction and neuroendocrine differentiation.

RESULTS

Androgen deprivation therapy induced a decrease in YY1 protein ubiquitination, enhanced its stability, and thus enhanced the transcriptional activity of FZD8. Castration enhanced FZD8 binding to Wnt9A and mediated cellular plasticity by activating the non-canonical Wnt (FZD8/FYN/STAT3) pathway.

CONCLUSIONS

We identified YY1 as a novel dysregulated transcription factor that plays an important role in NEPC progression in this study. We believe that an in-depth investigation of the mechanism underlying YY1-mediated disease may lead to improved NEPC therapies.

Binding of YY1/CREB to an Enhancer Region Triggers Claudin 6 Expression in H. pylori LPS-Stimulated AGS Cells

Aberrant expression of the tight junction protein claudin 6 (CLDN6) is a hallmark of gastric cancer progression. Its expression is regulated by the cAMP response element-binding protein (CREB). In gastric cancer induced by Helicobacter pylori (H. pylori) there is no information regarding what transcription factors induce/upregulate the expression of CLDN6. We aimed to identify whether CREB and Yin Yang1 (YY1) regulate the expression of CLDN6 and the site where they bind to the promoter sequence. Bioinformatics analysis, H. pylori lipopolysaccharide (LPS), YY1 and CREB silencing, Western blot, luciferase assays, and chromatin immunoprecipitation experiments were performed using the stomach gastric adenocarcinoma cell line AGS. A gen reporter assay suggested that the initial 2000 bp contains the regulatory sequence associated with CLDN6 transcription; the luciferase assay demonstrated three different regions with transcriptional activity, but the -901 to -1421 bp region displayed the maximal transcriptional activity in response to LPS. Fragment 1279-1421 showed CREB and, surprisingly, YY1 occupancy. Sequential Chromatin Immunoprecipitation (ChIP) experiments confirmed that YY1 and CREB interact in the 1279-1421 region. Our results suggest that CLDN6 expression is regulated by the binding of YY1 and CREB in the 901-1421 enhancer, in which a non-described interaction of YY1 with CREB was established in the 1279-1421 region.

Role of YY1 in the Regulation of Anti-Apoptotic Gene Products in Drug-Resistant Cancer Cells

Cancer is a leading cause of death among the various diseases encountered in humans. Cancer is not a single entity and consists of numerous different types and subtypes that require various treatment regimens. In the last decade, several milestones in cancer treatments were accomplished, such as specific targeting agents or revitalizing the dormant anti-tumor immune response. These milestones have resulted in significant positive clinical responses as well as tumor regression and the prolongation of survival in subsets of cancer patients. Hence, in non-responding patients and non-responding relapsed patients, cancers develop intrinsic mechanisms of resistance to cell death via the overexpression of anti-apoptotic gene products. In parallel, the majority of resistant cancers have been reported to overexpress a transcription factor, Yin Yang 1 (YY1), which regulates the chemo-immuno-resistance of cancer cells to therapeutic anticancer cytotoxic agents. The relationship between the overexpression of YY1 and several anti-apoptotic gene products, such as B-cell lymphoma 2 protein (Bcl-2), B-cell lymphoma extra-large (Bcl-xL), myeloid cell leukemia 1 (Mcl-1) and survivin, is investigated in this paper. The findings demonstrate that these anti-apoptotic gene products are regulated, in part, by YY1 at the transcriptional, epigenetic, post-transcriptional and translational levels. While targeting each of the anti-apoptotic gene products individually has been examined and clinically tested for some, this targeting strategy is not effective due to compensation by other overexpressed anti-apoptotic gene products. In contrast, targeting YY1 directly, through small interfering RNAs (siRNAs), gene editing or small molecule inhibitors, can be therapeutically more effective and generalized in YY1-overexpressed resistant cancers.

Targeting Transcription Factor YY1 for Cancer Treatment: Current Strategies and Future Directions

Cancer represents a significant and persistent global health burden, with its impact underscored by its prevalence and devastating consequences. Whereas numerous oncogenes could contribute to cancer development, a group of transcription factors (TFs) are overactive in the majority of tumors. Targeting these TFs may also combat the downstream oncogenes activated by the TFs, making them attractive potential targets for effective antitumor therapeutic strategy. One such TF is yin yang 1 (YY1), which plays crucial roles in the development and progression of various tumors. In preclinical studies, YY1 inhibition has shown efficacy in inhibiting tumor growth, promoting apoptosis, and sensitizing tumor cells to chemotherapy. Recent studies have also revealed the potential of combining YY1 inhibition with immunotherapy for enhanced antitumor effects. However, clinical translation of YY1-targeted therapy still faces challenges in drug specificity and delivery. This review provides an overview of YY1 biology, its role in tumor development and progression, as well as the strategies explored for YY1-targeted therapy, with a focus on their clinical implications, including those using small molecule inhibitors, RNA interference, and gene editing techniques. Finally, we discuss the challenges and current limitations of targeting YY1 and the need for further research in this area.

Dissecting the roles and clinical potential of YY1 in the tumor microenvironment

Yin-Yang 1 (YY1) is a member of the GLI-Kruppel family of zinc finger proteins and plays a vital dual biological role in cancer as an oncogene or a tumor suppressor during tumorigenesis and tumor progression. The tumor microenvironment (TME) is identified as the “soil” of tumor that has a critical role in both tumor growth and metastasis. Many studies have found that YY1 is closely related to the remodeling and regulation of the TME. Herein, we reviewed the expression pattern of YY1 in tumors and summarized the function and mechanism of YY1 in regulating tumor angiogenesis, immune and metabolism. In addition, we discussed the potential value of YY1 in tumor diagnosis and treatment and provided a novel molecular strategy for the clinical diagnosis and treatment of tumors.

Identification of Hub Genes for Colorectal Cancer with Liver Metastasis Using miRNA-mRNA Network

Background

Liver metastasis is an important cause of death in patients with colorectal cancer (CRC). Increasing evidence indicates that microRNAs (miRNAs) are involved in the pathogenesis of colorectal cancer liver metastasis (CRLM). This study is aimed at exploring the potential miRNA-mRNA regulatory network.

Methods

From the GEO database, we downloaded the microarray datasets GSE56350 and GSE73178. GEO2R was used to conduct differentially expressed miRNAs (DEMs) between CRC and CRLM using the GEO2R tool. Then, GO and KEGG pathway analysis for differentially expressed genes (DEGs) performed via DAVID. A protein-protein interaction (PPI) network was constructed by the STRING and identified by Cytoscape. Hub genes were identified by miRNA-mRNA network. Finally, the expression of the hub gene expression was assessed in the GSE81558.

Results

The four DEMs (hsa-miR-204-5p, hsa-miR-122-5p, hsa-miR-95-3p, and hsa-miR-552-3p) were identified as common DEMs in GSE56350 and GSE73178 datasets. The SP1 was likely to adjust the upregulated DEMs; however, the YY1 could regulate both the upregulated and downregulated DEMs. A total of 3925 genes (3447 upregulated DEM genes and 478 downregulated DEM genes) were screened. These predicted genes were mainly linked to Platinum drug resistance, Cellular senescence, and ErbB signaling pathway. Through the gene network construction, most of the hub genes were found to be modulated by hsa-miR-204-5p, hsa-miR-122-5p, hsa-miR-95-3p, and hsa-miR-552-3p. Among the top 20 hub genes, the expression of CREB1, RHOA, and EGFR was significantly different in the GSE81558 dataset.

Conclusion

In this study, miRNA-mRNA networks in CRLM were screened between CRC patients and CRLM patients to provide a new method to predict for the pathogenesis and development of CRC.

Chromatin and noncoding RNA-mediated mechanisms of gastric tumorigenesis

Gastric cancer (GC) is one of the most common and deadly cancers in the world. It is a multifactorial disease highly influenced by environmental factors, which include radiation, smoking, diet, and infectious pathogens. Accumulating evidence suggests that epigenetic regulators are frequently altered in GC, playing critical roles in gastric tumorigenesis. Epigenetic regulation involves DNA methylation, histone modification, and noncoding RNAs. While it is known that environmental factors cause widespread alterations in DNA methylation, promoting carcinogenesis, the chromatin- and noncoding RNA-mediated mechanisms of gastric tumorigenesis are still poorly understood. In this review, we focus on discussing recent discoveries addressing the roles of histone modifiers and noncoding RNAs and the mechanisms of their interactions in gastric tumorigenesis. A better understanding of epigenetic regulation would likely facilitate the development of novel therapeutic approaches targeting specific epigenetic regulators in GC.

LINC00858 stabilizes RAN expression and promotes metastasis of gastric cancer

Metastasis constitutes one of the major causes of tumor-related death in gastric cancer (GC), and understanding key events in the initiation of this phenotypic switch may provide therapeutic opportunities. Long noncoding RNAs (lncRNAs) are emerging as molecules that play vital roles in tumorigenesis and metastasis. In this study, we aimed to identify metastasis-related lncRNAs in the context of GC. The lncRNAs overexpressed in tumor tissues and positively associated with overall survival were screened out using the TCGA database. qPCR assays in clinical samples showed that LINC00858 was significantly upregulated in GC tissues compared with normal counterparts. Functional analysis suggested that LINC00858 depletion attenuated the migration, and invasion of cancer cells in vitro and suppressed the metastasis of xenografted tumors in vivo. Mechanistically, LINC00858 could interact with the metastasis-associated RAN and stabilize its protein expression by decreasing posttranslational ubiquitination. The transcription factor YY1 could bind to the promoter of LINC00858 to upregulate its expression in GC cells. Moreover, overexpression of YY1 and RAN was positively associated with upregulation of LINC00858 in GC tissues. Our results suggest that LINC00858 might play a role in GC metastasis, and be a diagnostic biomarker and potential therapeutic target.

PLK2 Single Nucleotide Variant in Gastric Cancer Patients Affects miR-23b-5p Binding

PURPOSE

Chromosomal instability is a hallmark of gastric cancer (GC). It can be driven by single nucleotide variants (SNVs) in cell cycle genes. We investigated the associations between SNVs in candidate genes, PLK2, PLK3, and ATM, and GC risk and clinicopathological features.

MATERIALS AND METHODS

The genotyping study included 542 patients with GC and healthy controls. Generalized linear models were used for the risk and clinicopathological association analyses. Survival analysis was performed using the Kaplan-Meier method. The binding of candidate miRs was analyzed using a luciferase reporter assay.

RESULTS

The PLK2 Crs15009-Crs963615 haplotype was under-represented in the GC group compared to that in the control group (Pcorr=0.050). Male patients with the PLK2 rs963615 CT genotype had a lower risk of GC, whereas female patients had a higher risk (P=0.023; P=0.026). The PLK2 rs963615 CT genotype was associated with the absence of vascular invasion (P=0.012). The PLK3 rs12404160 AA genotype was associated with a higher risk of GC in the male population (P=0.015). The ATM Trs228589-Ars189037-Grs4585 haplotype was associated with a higher risk of GC (P<0.001). The ATM rs228589, rs189037, and rs4585 genotypes TA+AA, AG+GG, and TG+GG were associated with the absence of perineural invasion (P=0.034). In vitro analysis showed that the cancer-associated miR-23b-5p mimic specifically bound to the PLK2 rs15009 G allele (P=0.0097). Moreover, low miR-23b expression predicted longer 10-year survival (P=0.0066) in patients with GC.

CONCLUSIONS

PLK2, PLK3, and ATM SNVs could potentially be helpful for the prediction of GC risk and clinicopathological features. PLK2 rs15009 affects the binding of miR-23b-5p. MiR-23b-5p expression status could serve as a prognostic marker for survival in patients with GC.

Inhibition of NLRC5 attenuates the malignant growth and enhances the sensitivity of gastric cancer cells to 5‑FU chemotherapy by blocking the carcinogenic effect of YY1

Gastric cancer (GC) is one of the commonest malignant tumors of the digestive system, characterized by high morbidity and mortality rates. It has been reported that NOD like receptor (NLR) family, CARD domain containing 5 (NLRC5) serves an important role in the occurrence and development of GC. Therefore, the current study aimed to investigate the role of NLRC5 in GC. The mRNA and protein expression levels of NLRC5 in GC cell lines were determined by reverse transcription-quantitative PCR and western blot analysis, respectively. Additionally, following NLRC5 knockdown, cell proliferation, invasion and migration were evaluated using Cell Counting Kit 8, colony formation, wound healing and Transwell assays, and western blot analysis. The NLRC and Yin Yang 1 (YY1) expression in the AGS cells with 5-FU resistance were detected by western blotting. The sensitivity of GC cells to 5-fluorouracil (5-FU) was detected by flow cytometry and western blot analysis. Additionally, the binding capacity of YY1 on NLRC5 promoter was predicted using JASPAR database and it was further verified by chromatin immunoprecipitation and luciferase reporter assays. Finally, to elucidate the mechanism underlying the effect of NLRC5 on GC, YY1 was overexpressed and NLRC5 was silenced in GC cell lines. The results showed that NLRC5 was abnormally upregulated in GC cells. In addition, NLRC5 knockdown significantly attenuated the proliferation, invasion and migration abilities of GC cells, while it enhanced the sensitivity of GC cells to 5-FU. The above effects were regulated by the YY1 transcription factor. Overall, the results of the present study indicated that NLRC5 silencing could reduce the malignant growth and enhance the sensitivity of GC cells to 5-FU chemotherapy via inhibiting the carcinogenic effect of YY1.

Transcription factor YY1 contributes to human melanoma cell growth through modulating the p53 signaling pathway

BACKGROUND

Melanoma has a higher mortality rate than any other skin cancer, and its cases are increasing. The transcription factor YY1 has been proven to be involved in tumor progression; however, the role of YY1 in melanoma is not well understood.

METHODS

This study investigates how YY1 functions in melanoma progression, and it also elucidates the underlying mechanisms involved.

RESULTS

We have found that in clinical human melanoma tissues, YY1 is overexpressed compared to YY1 expression in normal melanocytes and skin tissues. Cellular immunofluorescence shows that YY1 is mainly located in the nucleus. YY1 knockdown reduces proliferation, migration, and invasion of melanoma cell lines. Moreover, the apoptosis rate of cells is significantly increased in low-YY1 environments. The overexpression of YY1 resulted in decreased apoptotic rates in melanoma cells. YY1 also affects the expression of EMT-related proteins. Additional experiments reveal that YY1 knockdown disrupts the interaction of MDM2-p53, and that it both stabilizes and increases p53 activity. The upregulation of p53 expression in turn stimulates p21 expression just as it suppresses CDK4 expression, which then induces cells that were arrested in the G1 phase. The effect then is to constrain cell proliferation in melanoma cells. Upon activation of the p53 pathway, Bax, a pro-apoptotic protein, is upregulated, and Bcl-2, an anti-apoptotic protein, was downregulated in A375 cells.

CONCLUSIONS

The findings of this study provide novel insights into the pathology of melanoma as well as the role that YY1 plays in tumor progression. The findings also suggest that targeting YY1 has the potential to improve the diagnosis and treatment of melanoma.

Yin Yang 1 regulates ITGAV and ITGB1, contributing to improved prognosis of colorectal cancer

Yin Yang 1 (YY1) is a multifunctional transcription factor with critical roles in carcinogenesis and metastasis. However, its biological role and clinical impact in colorectal cancer (CRC) remain unclear. In the present study, the function and underlying molecular mechanisms of YY1 in CRC progression were investigated. The immunohistochemistry (IHC) of 143 CRC tissues revealed a significant correlation of low YY1 expression with aggressive clinicopathological features, increased metastasis and recurrence and poor patient survival. Multivariate analysis identified low YY1 expression as an independent poor prognostic factor. Subsequently, the IHC of 66 paired CRC primary tumor and liver metastasis tissues revealed that low YY1 expression in the primary CRC was significantly associated with multiple liver metastases, major hepatectomy, extrahepatic metastasis and poor prognosis. In vitro experiments revealed that YY1 knockdown promoted the migration and invasion of CRC cells. To examine the downstream genes of YY1, a cDNA microarray assay was conducted and the differentially expressed genes between the YY1‑knockdown and control cells were compared. Integrin alpha V (ITGAV) and integrin beta 1 (ITGB1) were identified as upregulated hub genes using gene enrichment analysis and protein‑protein interaction analyses. Western blotting and IHC confirmed YY1 expression to be negatively correlated with ITGAV and ITGB1 expression. In summary, it was revealed that YY1, as a tumor‑suppressor in CRC, contributes to the survival of patients with CRC. Low YY1 expression was associated with the poor prognosis of the patients with primary CRC and liver metastases. YY1 suppressed the expression of ITGAV and ITGB1, and this transcriptional regulation may lead to the suppression of CRC cell migration and invasion.

YY1-mediated reticulocalbin-2 upregulation promotes the hepatocellular carcinoma progression via activating MYC signaling

Hepatocellular carcinoma (HCC) is a common digestive tumor with high fatality worldwide. Previous studies have shown that Reticulocalbin-2 (RCN2) was a crucial factor for HCC proliferation, but invasion and migration mechanism of RCN2 contributing to HCC is poorly investigated. In this study, we estimated the RCN2 expression in both patient tissues and cell lines by polymerase chain reaction (PCR) and western blotting (WB), as well as the clinical information of HCC patients from public databases. Biological function induced by RCN2 in vitro and vivo was also researched through multiple functional experiments. Upstream and downstream signal of RCN2 was identified by bioinformatics. We found that up-regulated RCN2 was related to poorer prognosis in HCC patients and attached significance to HCC proliferation, invasion and migration. Luciferase reporter assay and chromatin immunoprecipitation validated that YY1 as the upstream transcription factor of RCN2, facilitating the expression of RCN2. Gene set enrichment analysis indicated that HCC progression induced by RCN2 might be related to MYC signaling. Furthermore, we demonstrated RCN2 reduced proteasomal degradation of MYC and lead to HCC progression. The effects of overexpressed RCN2 in HCC were attenuated by MYC silencing. In conclusion, our study highlighted the vital role of RCN2 in tumor progression and the potential benefit for the treatment of HCC.

Relationship between miR-378c and YY1 expression in patients with gastric cancer and the clinicopathological features

Background

The purpose of this study was to explore the clinical value of miR-378c and its target gene YY1 in gastric cancer.

Methods

The TCGA database was employed to analyse miR-378c expression in gastric cancer. qRT-PCR was applied to identify miR-378c and YY1 in tissues and serum of patients suffering from gastric cancer. The association of miR-378c with the clinical data of patients with gastric cancer was analysed. Receiver operating characteristics (ROC) curve analysis was used to determine the diagnostic value of miR-378c and YY1 in gastric cancer, and analyse the relationship between miR-378c and YY1 and patients’ survival. Pearson’s test was applied to determine the association between miR-378c and YY1 in tissue and serum of patients. Dual-Luciferase Reporter assay was employed to examine the targeting association between miR-378c and YY1. Finally, independent prognostic factors was determined in patients with gastric cancer using Cox regression analysis.

Results

In the TCGA database, miR-378c was weakly expressed in gastric cancer. Overall, patients with low expression had a lower survival rate. The expression of miR-378c decreased and the expression of YY1 increased in cancer tissues and serum of tumour patients. In patients with low expression of miR-378c the tumour size was ≥ 5 cm. Low differentiation, high TNM staging and lymph node invasion rate increased significantly, but the 5-year survival rate decreased in the patients. miR-378c and YY1 had better diagnostic value in gastric cancer. TargetScan, miRDB, starBase and miRTarBase predicted that YY1 was a potential gene of miR-378c, and the Dual-Luciferase Reporter assay revealed that there was a targeting relationship between the two, which was proved by correlation analysis. Multivariate Cox analysis revealed that differentiation, TNM staging and miR-378c were independent prognostic factors for patients.

Conclusions

MiR-378c is weakly expressed in gastric cancer patients and may be considered as a promising diagnostic and prognostic indicator for gastric cancer.

Roles Played by YY1 in Embryonic, Adult and Cancer Stem Cells

Accumulating evidence strongly indicates that the presence of cancer stem cells (CSCs) leads to the emergence of worse clinical scenarios, such as chemo- and radiotherapy resistance, metastasis, and cancer recurrence. CSCs are a highly tumorigenic population characterized by self-renewal capacity and differentiation potential. Thus, CSCs establish a hierarchical intratumor organization that enables tumor adaptation to evade the immune response and resist anticancer therapy. YY1 functions as a transcription factor, RNA-binding protein, and 3D chromatin regulator. Thus, YY1 has multiple effects and regulates several molecular processes. Emerging evidence indicates that the development of lethal YY1-mediated cancer phenotypes is associated with the presence of or enrichment in cancer stem-like cells. Therefore, it is necessary to investigate whether and to what extent YY1 regulates the CSC phenotype. Since CSCs mirror the phenotypic behavior of stem cells, we initially describe the roles played by YY1 in embryonic and adult stem cells. Next, we scrutinize evidence supporting the contributions of YY1 in CSCs from a number of various cancer types. Finally, we identify new areas for further investigation into the YY1-CSCs axis, including the participation of YY1 in the CSC niche.

YY1 regulated transcription-based stratification of gastric tumors and identification of potential therapeutic candidates

Gastric cancer is one of the leading causes of cancer-related death worldwide. The transcription factor YY1 regulates diverse biological processes, including cell proliferation, development, DNA damage responses, and carcinogenesis. This study was designed to explore the role of YY1 regulated transcription in gastric cancer. YY1 silencing in gastric cancer cells has resulted in the inhibition of Wnt/β-catenin, JNK/MAPK, ERK/MAPK, ER, and HIF-1α signaling pathways. Genome-wide mRNA profiling upon silencing the expression YY1 gene in gastric cancer cells and comparison with the previously identified YY1 regulated genes from other lineages revealed a moderate overlap among the YY1 regulated genes. Despite the differing genes, all the YY1 regulated gene sets were expressed in most of the intestinal subtype gastric tumors and a subset of diffuse subtype gastric tumors. Integrative functional genomic analysis of the YY1 gene sets revealed an association among the pathways Wnt/β-catenin, Rapamycin, Cyclin-D1, Myc, E2F, PDGF, and AKT. Further, the drugs capable of inhibiting YY1 mediated transcription were identified as suitable targeted therapeutic candidates for gastric tumors with activated YY1. The data emerging from the investigation would pave the way for the development of YY1-based targeted therapeutics for gastric cancer.

Development of a cell-based pathway modulator screening system to screen the targeted cancer therapeutic candidates

To overcome the issues of poor prognosis and to tackle the non-responsiveness to various chemotherapeutics; it is necessary to develop targeted cancer therapeutic agents. Also, it is being necessary to understand the molecular targets of the drug candidates and drugs in the context of cellular signaling pathways, to make progress towards the development of targeted cancer therapeutics. Towards addressing these, we have established a cell-based and pathway-focused drug screening system for the pathways such as MYC, E2F, WNT, ERK, NRF1/2, HIF1α, p53, YY1 and NFκB. These signaling pathways are highly dysregulated in many cancers, including gastric cancer. The developed firefly luciferase assay-based screening system in gastric cancer lineage is suitable for the screening of the massive panel of drugs, drug candidates, small molecule inhibitors, chemicals and alternate drug formulations. The developed stable cell lines have been demonstrated for their pathway activity reporting features using the corresponding pathway-specific modulators. A proof-of-concept medium throughput screening focusing on YY1 signaling pathway also revealed the connection between calcium channel blockers and YY1 signaling. The developed signaling pathway screening assay cells are valuable resource and will serve as the screening platform for screening the drug libraries towards the development of targeted cancer therapeutics.

Transcription factor YY1 enhances the stemness of lung cancer cells by stabilizing hypoxia factor HIF-1α under a hypoxic microenvironment

The hypoxic microenvironment can facilitate the tumor progression, and transcription factor YY1 holds promoting effects in various tumors. This work aims to investigate whether YY1 is involved in hypoxia-induced stemness of lung cancer cells. We showed that hypoxic microenvironment induced the expression of HIF-1α and YY1, and the stemness of lung cancer cells, which was attenuated by YY1 knockdown. Additionally, we found that YY1 regulates the hypoxia-induced stemness in a HIF-1α-dependent manner, but independent on p53 expression. Further analysis revealed that YY1 physically interacted with HIF-1α protein and stabilized HIF-1α protein. Our work indicates a novel YY1/HIF-1α axis regulating the stemness of lung cancer cells.

Loss of YY1 expression predicts unfavorable prognosis in stage III colorectal cancer

Background

Yin Yang 1 (YY1), the multifunctional transcription factor, has recently been assigned biological properties related to human malignancies. YY1 can facilitate both tumor suppression and tumor growth. The conflicting role of YY1 in human malignancies is not yet fully explained.

Objective

In this study, we determined the clinicopathologic significance and prognostic role of YY1 in stage III colorectal cancer (CRC).

Materials and Methods

YY1 expression was evaluated immunohistochemically in tissue microarray from 345 CRCs. YY1 expression was scored by the proportion of tumor cells with nuclear staining into 4 scores (0, none; 1+, ≤10%; 2+, 10 to ≤25%; 3+, >25%). A score of 0 and 1 were considered as loss of expression.

Results

Loss of YY1 expression was observed in 49 (14.2%) out of 345 CRCs and was associated with larger tumor size (P = 0.004), tumor deposit (P = 0.008), and higher pathologic tumor (pT) stage (P = 0.004). In stage III group, loss of YY1 expression was associated with larger tumor size (P = 0.027) and tumor deposit (P = 0.011). Kaplan-Meier survival curves revealed no significant difference between patients with YY1 loss and patients with intact YY1 in both cancer-specific survival and recurrence-free survival (P = 0.330 and P = 0.470, respectively). In American Joint Committee on Cancer (AJCC) stage subgroup, loss of YY1 expression was associated with poor recurrence-free survival in AJCC stage III CRC (P = 0.038).

Conclusion

Loss of YY1 expression was significantly associated with aggressive phenotypes and poor patient outcome in AJCC stage III CRC.

The Ubiquitin Gene Expression Pattern and Sensitivity to UBB and UBC Knockdown Differentiate Primary 23132/87 and Metastatic MKN45 Gastric Cancer Cells

Gastric cancer (GC) is one of the most common and lethal cancers. Alterations in the ubiquitin (Ub) system play key roles in the carcinogenetic process and in metastasis development. Overexpression of transcription factors YY1, HSF1 and SP1, known to regulate Ub gene expression, is a predictor of poor prognosis and shorter survival in several cancers. In this study, we compared a primary (23132/87) and a metastatic (MKN45) GC cell line. We found a statistically significant higher expression of three out of four Ub coding genes, UBC, UBB and RPS27A, in MKN45 compared to 23132/87. However, while the total Ub protein content and the distribution of Ub between the conjugated and free pools were similar in these two GC cell lines, the proteasome activity was higher in MKN45. Ub gene expression was not affected upon YY1, HSF1 or SP1 small interfering RNA (siRNA) transfection, in both 23132/87 and MKN45 cell lines. Interestingly, the simultaneous knockdown of UBB and UBC mRNAs reduced the Ub content in both cell lines, but was more critical in the primary GC cell line 23132/87, causing a reduction in cell viability due to apoptosis induction and a decrease in the oncoprotein and metastatization marker β-catenin levels. Our results identify UBB and UBC as pro-survival genes in primary gastric adenocarcinoma 23132/87 cells.

The biological implications of Yin Yang 1 in the hallmarks of cancer

Tumorigenesis is a multistep process characterized by the acquisition of genetic and epigenetic alterations. During the course of malignancy development, tumor cells acquire several features that allow them to survive and adapt to the stress-related conditions of the tumor microenvironment. These properties, which are known as hallmarks of cancer, include uncontrolled cell proliferation, metabolic reprogramming, tumor angiogenesis, metastasis, and immune system evasion. Zinc-finger protein Yin Yang 1 (YY1) regulates numerous genes involved in cell death, cell cycle, cellular metabolism, and inflammatory response. YY1 is highly expressed in many cancers, whereby it is associated with cell proliferation, survival, and metabolic reprogramming. Furthermore, recent studies also have demonstrated the important role of YY1-related non-coding RNAs in acquiring cancer-specific characteristics. Therefore, these YY1-related non-coding RNAs are also crucial for YY1-mediated tumorigenesis. Herein, we summarize recent progress with respect to YY1 and its biological implications in the context of hallmarks of cancer.

The USP21/YY1/SNHG16 axis contributes to tumor proliferation, migration, and invasion of non-small-cell lung cancer

Deubiquitinases (DUBs) and noncoding RNAs have been the subjects of recent extensive studies regarding their roles in lung cancer, but the mechanisms involved are largely unknown. In our study, we used The Cancer Genome Atlas data set and bioinformatics analyses and identified USP21, a DUB, as a potential contributor to oncogenesis in non-small-cell lung cancer (NSCLC). We further demonstrated that USP21 was highly expressed in NSCLCs. We then conducted a series of in vitro and in vivo assays to explore the effect of USP21 on NSCLC progression and the underlying mechanism involved. USP21 promoted NSCLC cell proliferation, migration, and invasion and in vivo tumor growth by stabilizing a well-known oncogene, Yin Yang-1 (YY1), via mediating its deubiquitination. Furthermore, YY1 transcriptionally regulates the expression of SNHG16. Moreover, StarBase bioinformatics analyses predicted that miR-4500 targets SNHG16 and USP21. A series of in vitro experiments indicated that SNHG16 increased the expression of USP21 through miR-4500. In summary, the USP21/YY1/SNHG16 axis plays a role in promoting the progression of NSCLC. Therefore, the USP21/YY1/SNHG16/miR-4500 axis may be a potential therapeutic target in NSCLC treatment.

Therapies targeting a molecular feedback loop involved in tumor growth may prove valuable for treating non-small-cell lung cancer. Fangbao Ding, Jianbing Huang, and co-workers at Shanghai Jiao Tong University in Shanghai, China, have shown how an enzyme called USP21 promotes cancer cell proliferation and tumor growth in non-small-cell lung cancer. The team took cancerous and non-cancerous lung tissue samples from 42 patients, and analyzed the expression and behavior of USP21. The enzyme was highly expressed in cancerous tissues, where it stabilized a known gene with the potential to cause cancer called YY1. This gene also regulated the expression of a particular RNA molecule, which in turn worked to increase levels of USP21. This cyclical process encouraged the proliferation, migration and invasion of non-small-cell lung cancer cells, and may provide a future therapeutic target.

Hybrid 18F-FDG-PET/MRI Measurement of Standardized Uptake Value Coupled with Yin Yang 1 Signature in Metastatic Breast Cancer. A Preliminary Study

Purpose: Detection of breast cancer (BC) metastasis at the early stage is important for the assessment of BC progression status. Image analysis represents a valuable tool for the management of oncological patients. Our preliminary study combined imaging parameters from hybrid ¹⁸F-FDG-PET/MRI and the expression level of the transcriptional factor Yin Yang 1 (YY1) for the detection of early metastases. Methods: The study enrolled suspected n = 217 BC patients that underwent ¹⁸F-FDG-PET/MRI scans. The analysis retrospectively included n = 55 subjects. n = 40 were BC patients and n = 15 imaging-negative female individuals were healthy subjects (HS). Standard radiomics parameters were extracted from PET/MRI image. RNA was obtained from peripheral blood mononuclear cells and YY1 expression level was evaluated by real time reverse transcription polymerase chain reactions (qRT-PCR). An enzyme-linked immuosorbent assay (ELISA) was used to determine the amount of YY1 serum protein. Statistical comparison between subgroups was evaluated by Mann-Whitney U and Spearman’s tests. Results: Radiomics showed a significant positive correlation between Greg-level co-occurrence matrix (GLCM) and standardized uptake value maximum (SUVmax) (r = 0.8 and r = 0.8 respectively) in BC patients. YY1 level was significant overexpressed in estrogen receptor (ER)-positive/progesteron receptor-positive/human epidermal growth factor receptor2-negative (ER+/PR+/HER2-) subtype of BC patients with synchronous metastasis (SM) at primary diagnosis compared to metachronous metastasis (MM) and HS (p < 0.001) and correlating significantly with ¹⁸F-FDG-uptake parameter (SUVmax) (r = 0.48). Conclusions: The combination of functional ¹⁸F-FDG-PET/MRI parameters and molecular determination of YY1 could represent a novel integrated approach to predict synchronous metastatic disease with more accuracy than ¹⁸F-FDG-PET/MRI alone.

YY1 inhibits the migration and invasion of pancreatic ductal adenocarcinoma by downregulating the FER/STAT3/MMP2 signaling pathway

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis and a high mortality rate. The transcription factor YY1 acts as an inhibitor of many types of tumors. We found that YY1 knockdown promoted the invasion and migration of PANC-1 and BxPC-3 cells; FER knockdown partially restored the promotion of pancreatic cancer caused by YY1 knockdown. In vivo experiments yielded the same results. According to luciferase reporter gene, electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays, YY1 directly binds to the FER promoter region. Moreover, higher level FER expression results in a worse TNM stage and prognosis for patients with PDAC. Furthermore, by downregulating FER, YY1 inhibits the formation of the STAT3-MMP2 complex, thereby suppressing expression of MMP2 and ultimately inhibiting the migration and invasion of pancreatic cancer. Our study demonstrates that the YY1/FER/STAT3/MMP2 axis is associated with the progression of pancreatic cancer and may provide a new therapeutic target for the treatment of pancreatic cancer.

YY1 regulates cancer cell immune resistance by modulating PD-L1 expression

Recent advances in the treatment of various cancers have resulted in the adaptation of several novel immunotherapeutic strategies. Notably, the recent intervention through immune checkpoint inhibitors has resulted in significant clinical responses and prolongation of survival in patients with several therapy-resistant cancers (melanoma, lung, bladder, etc.). This intervention was mediated by various antibodies directed against inhibitory receptors expressed on cytotoxic T-cells or against corresponding ligands expressed on tumor cells and other cells in the tumor microenvironment (TME). However, the clinical responses were only observed in a subset of the treated patients; it was not clear why the remaining patients did not respond to checkpoint inhibitor therapies. One hypothesis stated that the levels of PD-L1 expression correlated with poor clinical responses to cell-mediated anti-tumor immunotherapy. Hence, exploring the underlying mechanisms that regulate PD-L1 expression on tumor cells is one approach to target such mechanisms to reduce PD-L1 expression and, therefore, sensitize the resistant tumor cells to respond to PD-1/PD-L1 antibody treatments. Various investigations revealed that the overexpression of the transcription factor Yin Yang 1 (YY1) in most cancers is involved in the regulation of tumor cells' resistance to cell-mediated immunotherapies. We, therefore, hypothesized that the role of YY1 in cancer immune resistance may be correlated with PD-L1 overexpression on cancer cells. This hypothesis was investigated and analysis of the reported literature revealed that several signaling crosstalk pathways exist between the regulations of both YY1 and PD-L1 expressions. Such pathways include p53, miR34a, STAT3, NF-kB, PI3K/AKT/mTOR, c-Myc, and COX-2. Noteworthy, many clinical and pre-clinical drugs have been utilized to target these above pathways in various cancers independent of their roles in the regulation of PD-L1 expression. Therefore, the direct inhibition of YY1 and/or the use of the above targeted drugs in combination with checkpoint inhibitors should result in enhancing the cell-mediated anti-tumor cell response and also reverse the resistance observed with the use of checkpoint inhibitors alone.

Expression of YY1 in Wilms tumors with favorable histology is a risk factor for adverse outcomes

Aim: To investigate the role of the transcription factor YY1 in Wilms tumor (WT). Patients & methods: We measured YY1 expression using tissue microarray from patients with pediatric renal tumors, mainly WT and evaluated correlations with the predicted clinical evolution. YY1 expression was measured using immunohistochemical and protein expression was determined by digital pathology. Results & conclusion: YY1 significantly increased in WT patients. In addition, an increase in YY1 expression had a greater risk of adverse outcomes in WT patients with favorable histology. YY1 expression was higher in the blastemal component of tumors, and high nuclear expression positively correlated with metastasis. YY1 may be considered as a metastasis risk factor in WT.

miR-544 inhibits the migration and invasion of anaplastic thyroid cancer by targeting Yin Yang-1

Anaplastic thyroid cancer (ATC), with a mean survival time of 6 months, was reported in 2012 to account for 1-2% of all thyroid tumor cases in the US. Understanding the molecular mechanisms underlying carcinogenesis and progression in ATC would contribute to determining novel therapeutic targets. The aberrant expression of microRNA-544 (miR-544) has been demonstrated in various cancer types. However, its expression and biological function in human ATC remain largely unknown. Therefore, the present study investigated the expression, function and molecular mechanism of miR-544 in ATC. Results of reverse transcription-quantitative polymerase chain reaction demonstrated that the expression levels of miR-544 in 40 pairs of surgical specimens and human ATC cell lines were significantly decreased, compared with the normal thyroid tissues and cell line. Functional assays indicated that ectopic expression of miR-544 significantly decreased the viability, proliferation and metastasis of SW1736 cells, whereas miR-544 inhibitor significantly enhanced the viability, proliferation and metastasis of 8305C cells. Furthermore, the present study confirmed that the oncogene Yin Yang-1 (YY1) was a direct target of miR-544. It was further demonstrated that YY1 overexpression rescued the inhibitory effect of progression induced by miR-544 in ATC cells. Finally, in vivo study indicated that miR-544 suppressed the tumorigenicity of ATC cells. In conclusion, the present study demonstrated that miR-544 may function as a tumor suppressor in ATC and serve as a future therapeutic target for patients with ATC.

miR-186 reverses cisplatin resistance and inhibits the formation of the glioblastoma-initiating cell phenotype by degrading Yin Yang 1 in glioblastoma

Glioblastoma multiforme (GBM) is among the most devastating types of cancer, with a median survival of <1 year. Despite the development of new surgical and radiation techniques, and the use of multiple anti‑neoplastic drugs, effective treatment strategies for malignant gliomas have not yet been developed. The limited efficacy of current treatments reflects the resistance of glioblastoma cells to cytotoxic agents. In this study, using western blot analysis, we found that Yin Yang 1 (YY1) expression was increased in cisplatin‑resistant glioblastoma U87MG cells (U87MG‑CR). We observed that the silencing of YY1 sensitized the U87MG‑CR cells to cisplatin and that the overexpression of YY1 promoted the resistance of LN‑229 glioblastoma cells to cisplatin, as shown by MTT assay. Using sphere formation assay, we also found that the silencing of YY1 inhibited the formation of the glioblastoma‑initiating cell (GIC) phenotype in the U87MG‑CR cells. In addition, the results of RT‑qPCR revealed that miR‑186 expression was decreased in U87MG‑CR cells. Using RT‑PCR and western blot analysis, we observed that overexpression of miR‑186 inhibited YY1 expression in U87MG‑CR cells. The overexpression of miR‑186 also reversed cisplatin resistance and the formation of the GIC phenotype in glioblastoma cells. On the whole, the findings of this study demonstrate that miR‑186 reverses cisplatin resistance and inhibits the formation of the GIC phenotype by degrading YY1 in glioblastoma.

YY1 suppresses proliferation and migration of pancreatic ductal adenocarcinoma by regulating the CDKN3/MdM2/P53/P21 signaling pathway

Pancreatic ductal adenocarcinoma (PDAC) is one of the malignant lethal tumors. It has been reported that the transcriptional regulator Yin Yang-1 (YY1) suppressed the invasion and metastasis of PDAC. However, the function of YY1 on proliferation and migration of pancreatic cancer remains to be clarified. In this study, we found that YY1 overexpression or knockdown can inhibit or promote the proliferation and migration of pancreatic cancer cells. Digital gene expression sequencing indicates that cyclin-dependent kinase inhibitor 3 (CDKN3) may be the candidate target gene of YY1. Then we found that YY1 can downregulate the expression of CDKN3 by directly binding to the promoter region of CDKN3. Silencing CDKN3 expression could inhibit the ability of cell proliferation and migration and overexpression of CDKN3 could restore the effects induced by YY1 overexpression in pancreatic cancer cells. The expression levels of YY1 and CDKN3 were negatively correlated in pancreatic cancer tissues and PDAC patients with higher levels of CDKN3 have poor prognosis. Vitro and vivo study show that CDKN3 can form a complex with MdM2-P53, thus leading to inhibiting the expression of P21, which is the target gene of P53, and finally facilitates the cell cycle to promote the proliferation of pancreatic cancer cells. Hence, YY1 can directly regulate the expression of CDKN3 and participate in the cycle of pancreatic cancer cells, which can inhibit the progression of pancreatic cancer. These results reveal that YY1-CDKN3-MDM2/P53-P21 axis is involved in pancreatic tumorigenesis, which may develop new methods for human pancreatic cancer therapy.

SRGAP1, a crucial target of miR-340 and miR-124, functions as a potential oncogene in gastric tumorigenesis

Slit-Robo GTPase-activating protein 1 (SRGAP1) functions as a GAP for Rho-family GTPases and downstream of Slit-Robo signaling. We aim to investigate the biological function of SRGAP1 and reveal its regulation by deregulated microRNAs (miRNAs) in gastric cancer (GC). mRNA and protein expression of SRGAP1 were examined by quantitative reverse transcription PCR (qRT-PCR) and western blot. The biological role of SRGAP1 was demonstrated through siRNA-mediated knockdown experiments. The regulation of SRGAP1 by miR-340 and miR-124 was confirmed by western blot, dual luciferase activity assays and rescue experiments. SRGAP1 is overexpressed in 9 out of 12 (75.0%) GC cell lines. In primary GC samples from TCGA cohort, SRGAP1 shows gene amplification in 5/258 (1.9%) of cases and its mRNA expression demonstrates a positive correlation with copy number gain. Knockdown of SRGAP1 in GC cells suppressed cell proliferation, reduced colony formation, and significantly inhibited cell invasion and migration. Luciferase reporter assays revealed that SRGAP1 knockdown significantly inhibited Wnt/β-catenin pathway. In addition, SRGAP1 was found to be a direct target of two tumor-suppressive miRNAs, miR-340 and miR-124. Concordantly, these two miRNAs were downregulated in primary gastric tumors and these decreasing levels w5ere associated with poor outcomes. Expression of miR-340 and SRGAP1 displayed a reverse relationship in primary samples and re-expressed SRGAP1, rescued the anti-cancer effects of miR-340. Taken together, these data strongly suggest that, apart from gene amplification and mutation, the activation of SRGAP1 in GC is partly due to the downregulation of tumor-suppressive miRNAs, miR-340 and miR-124. Thus SRGAP1 is overexpressed in gastric carcinogenesis and plays an oncogenic role through activating Wnt/β-catenin pathway.

Transcription Factor Activities Enhance Markers of Drug Sensitivity in Cancer

Transcriptional dysregulation induced by aberrant transcription factors (TF) is a key feature of cancer, but its global influence on drug sensitivity has not been examined. Here, we infer the transcriptional activity of 127 TFs through analysis of RNA-seq gene expression data newly generated for 448 cancer cell lines, combined with publicly available datasets to survey a total of 1,056 cancer cell lines and 9,250 primary tumors. Predicted TF activities are supported by their agreement with independent shRNA essentiality profiles and homozygous gene deletions, and recapitulate mutant-specific mechanisms of transcriptional dysregulation in cancer. By analyzing cell line responses to 265 compounds, we uncovered numerous TFs whose activity interacts with anticancer drugs. Importantly, combining existing pharmacogenomic markers with TF activities often improves the stratification of cell lines in response to drug treatment. Our results, which can be queried freely at dorothea.opentargets.io, offer a broad foundation for discovering opportunities to refine personalized cancer therapies.Significance: Systematic analysis of transcriptional dysregulation in cancer cell lines and patient tumor specimens offers a publicly searchable foundation to discover new opportunities to refine personalized cancer therapies. Cancer Res; 78(3); 769-80. ©2017 AACR.

Prognostic significance of high YY1AP1 and PCNA expression in colon adenocarcinoma

To investigate the relationship between YY1AP1 and various clinicopathological features of colon adenocarcinoma (COAD), we conducted immunohistochemical (IHC) analyses of human tissue microarrays. We found that YY1AP1 protein expression was significantly higher in tumor tissue of the colon and liver, and was significantly lower in tumor tissue of the kidney. An analysis that employed the SurvExpress database indicated that increased expression of YY1AP1 mRNA was significantly associated with the overall survival of COAD patients. To clarify the validity of YY1AP1 or PCNA as determined by the IHC analysis was performed on 59 paired samples from COAD and adjacent normal tissue. Statistically significant differences of immunoreactivity for YY1AP1 or PCNA protein expression was observed between COAD tissue and adjacent normal tissue. High protein expression levels of YY1AP1 and PCNA were also found to be significantly correlated with M-class and distant metastasis. We also determined that YY1AP1 was correlated with PCNA expression in COAD samples, and Kaplan-Meier survival curves indicated that YY1AP1 protein expression was significantly associated with poor survival. Finally, a univariate analysis demonstrated that YY1AP1 protein expression was related to YY1AP1 score, and multivariate analysis revealed that the YY1AP1 protein expression level was an independent risk factor of overall COAD survival. Taken together, our findings indicate that YY1AP1 expression plays an important role in the tumorigenesis and progression of COAD and could serve as a clinical prognostic indicator for COAD.

miRNA-584-3p inhibits gastric cancer progression by repressing Yin Yang 1- facilitated MMP-14 expression

Recent evidence shows the emerging roles of promoter-targeting endogenous microRNAs (miRNAs) in regulating gene transcription. However, miRNAs affecting the transcription of matrix metalloproteinase 14 (MMP-14) in gastric cancer remain unknown. Herein, through integrative mining of public datasets, we identified the adjacent targeting sites of Yin Yang 1 (YY1) and miRNA-584-3p (miR-584-3p) within MMP-14 promoter. We demonstrated that YY1 directly targeted the MMP-14 promoter to facilitate its expression in gastric cancer cells. In contrast, miR-584-3p recognized its complementary site within MMP-14 promoter to suppress its expression. Mechanistically, miR-584-3p interacted with Argonaute 2 to recruit enhancer of zeste homolog 2 and euchromatic histone lysine methyltransferase 2, resulting in enrichment of repressive epigenetic markers and decreased binding of YY1 to MMP-14 promoter. miR-584-3p inhibited the in vitro and in vivo tumorigenesis and aggressiveness of gastric cancer cells through repressing YY1-facilitated MMP-14 expression. In clinical gastric cancer tissues, the expression of YY1 and miR-584-3p was positively or negatively correlated with MMP-14 levels. In addition, miR-584-3p and YY1 were independent prognostic factors associated with favorable and unfavorable outcome of gastric cancer patients, respectively. These data demonstrate that miR-584-3p directly targets the MMP-14 promoter to repress YY1-facilitated MMP-14 expression and inhibits the progression of gastric cancer.

TEAD1/4 exerts oncogenic role and is negatively regulated by miR-4269 in gastric tumorigenesis

TEA domain (TEAD) transcription factors are key components of the Hippo–YAP1 signaling pathway, but their functional role and regulatory mechanisms remain unclear. This study aims to comprehensively explore the expression pattern and functional role of TEAD family in gastric carcinogenesis and investigate its regulation by microRNAs (miRNAs). The mRNA and protein expression of TEAD family were examined by quantitative reverse transcription–PCR (qRT–PCR) and western blot. Their functional roles were determined by in vitro and in vivo studies. The clinicopathological association of TEAD4 in gastric cancer (GC) was studied using immunohistochemistry on tissue microarray. The prediction of miRNAs, which potentially target TEAD1/4, was performed by TargetScan and miRDB. The regulation of TEAD1/4 by miRNAs was confirmed by qRT–PCR, western blot and luciferase assays. TEAD1/4 were overexpressed in GC cell lines and primary GC tissues. Knockdown of TEAD1/4 induced a significant anticancer effect in vitro and in vivo. TEAD1 was confirmed to be a direct target of miR-377-3p and miR-4269, while TEAD4 was negatively regulated by miR-1343-3p and miR-4269. Among them, miR-4269 was the most effective inhibitor of TEAD1/4. Ectopic expression of these miRNAs substantiated their tumor-suppressive effects. In primary GC tumors, downregulation of miR-4269 was associated with poor disease-specific survival and showed a negative correlation with TEAD4. TEAD1 and TEAD4 are oncogenic factors, whose aberrant activation are, in part, mediated by the silence of miR-377-3p, miR-1343-3p and miR-4269. For the first time, the nuclear accumulated TEAD4 and downregulated miR-4269 are proposed to serve as novel prognostic biomarkers in GC.

IGF2BP3 functions as a potential oncogene and is a crucial target of miR-34a in gastric carcinogenesis

Background

Gastric cancer (GC) is one of the frequent causes of cancer-related death in eastern Asian population. IGF2BP2 lists in the top rank up-regulated genes in GC, but its functional role is unclear.

Method

The expression of IGF2BP3 in GC cell lines and primary samples was examined by qRT-PCR and Western blot. The biological role of IGF2BP3 was revealed by a series of functional in vitro studies. Its regulation by microRNAs (miRNAs) was predicted by TargetScan and confirmed by luciferase assays and rescue experiments.

Results

IGF2BP3 ranked the No.1 of the up-regulated genes by expression microarray analysis in GC cell lines. The expression level of IGF2BP3 was observed in GC tissues comparing with non-tumorous gastric epitheliums. The up-regulated IGF2BP3 expression was associated with poor disease specific survival. IGF2BP3 knockdown significantly inhibited cell proliferation and invasion. Apart from copy number gain, IGF2BP3 has been confirmed to be negatively regulated by tumor-suppressive miRNA, namely miR-34a. The expression of miR-34a showed negative correlation with IGF2BP3 mRNA expression in primary GC samples and more importantly, re-overexpression of IGF2BP3 rescued the inhibitory effect of miR-34a.

Conclusion

We compressively revealed the oncogenic role of IGF2BP3 in gastric tumorigenesis and confirmed its activation is partly due to the silence of miR-34a. Our findings identified useful prognostic biomarker and provided clinical translational potential.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0647-2) contains supplementary material, which is available to authorized users.

Inverse correlation between the metastasis suppressor RKIP and the metastasis inducer YY1: Contrasting roles in the regulation of chemo/immuno-resistance in cancer

Several gene products have been postulated to mediate inherent and/or acquired anticancer drug resistance and tumor metastasis. Among these, the metastasis suppressor and chemo-immuno-sensitizing gene product, Raf Kinase Inhibitor Protein (RKIP), is poorly expressed in many cancers. In contrast, the metastasis inducer and chemo-immuno-resistant factor Yin Yang 1 (YY1) is overexpressed in many cancers. This inverse relationship between RKIP and YY1 expression suggests that these two gene products may be regulated via cross-talks of molecular signaling pathways, culminating in the expression of different phenotypes based on their targets. Analyses of the molecular regulation of the expression patterns of RKIP and YY1 as well as epigenetic, post-transcriptional, and post-translational regulation revealed the existence of several effector mechanisms and crosstalk pathways, of which five pathways of relevance have been identified and analyzed. The five examined cross-talk pathways include the following loops: RKIP/NF-κB/Snail/YY1, p38/MAPK/RKIP/GSK3β/Snail/YY1, RKIP/Smurf2/YY1/Snail, RKIP/MAPK/Myc/Let-7/HMGA2/Snail/YY1, as well as RKIP/GPCR/STAT3/miR-34/YY1. Each loop is comprised of multiple interactions and cascades that provide evidence for YY1's negative regulation of RKIP expression and vice versa. These loops elucidate potential prognostic motifs and targets for therapeutic intervention. Chiefly, these findings suggest that targeted inhibition of YY1 by specific small molecule inhibitors and/or the specific induction of RKIP expression and activity are potential therapeutic strategies to block tumor growth and metastasis in many cancers, as well as to overcome anticancer drug resistance. These strategies present potential alternatives for their synergistic uses in combination with low doses of conventional chemo-immunotherapeutics and hence, increasing survival, reducing toxicity, and improving quality of life.

miR-27b inhibits gastric cancer metastasis by targeting NR2F2

Increasing attention is focused on the down-regulation of miRNAs in cancer process. Nuclear receptor subfamily 2 (NR2F2, also known as COUP-TFII) is involved in the development of many types of cancers, but its role in gastric cancer remains elusive. In this experiment, oncomine and Kaplan-meier database revealed that NR2F2 was up-regulated in gastric cancer and that the high NR2F2 expression contributed to poor survival. MicroRNA-27b was targeted and down-regulated by NR2F2 in human gastric cancer tissues and cells. The ectopic expression of miR-27b inhibited gastric cancer cell proliferation and tumor growth in vitro and in vivo. Assays suggested that the overexpression of miR-27b could promote MGC-803 cells’ migration and invasion and retard their metastasis to the liver. In addition, down-regulation of miR-27b enhanced GES-1 cells’ proliferation and metastasis in vitro. These findings reveal that miR-27b is a tumor suppressor in gastric cancer and a biomarker for improving patients’ survival.

A critical role of transcription factor YY1 in rheumatoid arthritis by regulation of interleukin-6

Previous studies have revealed a critical role of YY1, a "Yin Yang" transcription factor, in cancer development and progression. However, whether YY1 has any role in rheumatoid arthritis (RA) remains unknown. This study aims to explore the potential role of YY1 in RA pathogenesis. In this study, we found that YY1 was over-expressed in RA patients and CIA mice. Blocking of YY1 action with YY1 shRNA lentivirus ameliorated disease progression in CIA mice. We further analyzed the signaling pathway involved by ingenuity pathway analysis (IPA), results showed IL-6 signaling and JAK/Stat signaling pathway was significantly inhibited by LV-YY1-shRNA treatment. Moreover, we observed that blocking of YY1 reduced IL-6 production and downregulated Th17 population. Finally, we showed YY1 positively regulated IL-6 transcription by binding to the promoter region of the IL-6 gene. In conclusion, YY1 plays a critical role in promoting IL-6 transcription in RA which contribute to the inflammation of RA via stimulation of Th17 differentiation. Thus, YY1 is likely a key molecule involved in the inflammation process of RA. Targeting of YY1 may be a novel therapeutic strategy for RA.

Yin Yang 1 is associated with cancer stem cell transcription factors (SOX2, OCT4, BMI1) and clinical implication

The transcription factor Yin Yang 1 (YY1) is frequently overexpressed in cancerous tissues compared to normal tissues and has regulatory roles in cell proliferation, cell viability, epithelial-mesenchymal transition, metastasis and drug/immune resistance. YY1 shares many properties with cancer stem cells (CSCs) that drive tumorigenesis, metastasis and drug resistance and are regulated by overexpression of certain transcription factors, including SOX2, OCT4 (POU5F1), BMI1 and NANOG. Based on these similarities, it was expected that YY1 expression would be associated with SOX2, OCT4, BMI1, and NANOG’s expressions and activities. Data mining from the proteomic tissue-based datasets from the Human Protein Atlas were used for protein expression patterns of YY1 and the four CSC markers in 17 types of cancer, including both solid and hematological malignancies. A close association was revealed between the frequency of expressions of YY1 and SOX2 as well as SOX2 and OCT4 in all cancers analyzed. Two types of dynamics were identified based on the nature of their association, namely, inverse or direct, between YY1 and SOX2. These two dynamics define distinctive patterns of BMI1 and OCT4 expressions. The relationship between YY1 and SOX2 expressions as well as the expressions of BMI1 and OCT4 resulted in the classification of four groups of cancers with distinct molecular signatures: 1) Prostate, lung, cervical, endometrial, ovarian and glioma cancers (YY1^loSOX2^hiBMI1^hiOCT4^hi) 2) Skin, testis and breast cancers (YY1^hiSOX2^loBMI1^hiOCT4^hi) 3) Liver, stomach, renal, pancreatic and urothelial cancers (YY1^loSOX2^loBMI1^hiOCT4^hi) and 4) Colorectal cancer, lymphoma and melanoma (YY1^hiSOX2^hiBMI1^loOCT4^hi). A regulatory loop is proposed consisting of the cross-talk between the NF-kB/PI3K/AKT pathways and the downstream inter-regulation of target gene products YY1, OCT4, SOX2 and BMI1.

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.

miR-508-3p concordantly silences NFKB1 and RELA to inactivate canonical NF-κB signaling in gastric carcinogenesis

Background

NF-κB signaling pathway plays an important role in gastric carcinogenesis. The basic expression and functional role of NFKB1 and RELA (components of canonical NF-κB pathway) in gastric cancer (GC) have not been well elucidated. In this study, the role of NFKB1 and RELA in gastric tumorigenesis will be investigated and their regulation by microRNAs (miRNAs) will be deeply explored.

Methods

The mRNA and protein expression of NFKB1 and RELA were investigated by qRT-PCR and Western blot in GC cell lines and primary tumors. The functional roles of NFKB1 and RELA in GC were demonstrated by MTT proliferation assay, monolayer colony formation, cell invasion and migration, cell cycle analysis and in vivo study through siRNA mediated knockdown. Identification of NFKB1 as a direct target of tumor suppressor miRNA miR-508-3p was achieved by expression regulation assays together with dual luciferase activity experiments.

Results

NFKB1 and RELA were up-regulated in GC cell lines and primary tumors compared with normal gastric epithelium cells and their upregulation correlation with poor survival in GC. siRNA mediated knockdown of NFKB1 or RELA exhibited anti-oncogenic effect both in vitro and in vivo. NFKB1 was further revealed to be a direct target of miR-508-3p in gastric tumorigenesis and their expression showed negative correlation in primary GC samples. miR-508-3p was down-regulated in GC cells compared with normal gastric epithelium samples and its ectopic expression in GC cell lines also exerts tumor suppressor function. NFKB1 re-expression was found to partly abolish the tumor-suppressive effect of miR-508-3p in GC.

Conclusion

All these findings supports that canonical NF-κB signaling pathway is activated in GC at least by the inactivation of miR-508-3p and this might have therapeutic potential in GC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0493-7) contains supplementary material, which is available to authorized users.

MiR-381 inhibits epithelial ovarian cancer malignancy via YY1 suppression

Epithelial ovarian cancer (EOC) is a common type of gynecologic cancer, which accounts for the majority of deaths among all gynecologic malignant tumors in developed countries. A series of recent studies suggested that miR-381 might play important roles in the development of various cancer types. However, the biological function of miR-381 in EOC remains to be investigated. We examined the levels of miR-381 expression in EOC tissues and cell lines. We identified miR-381 target genes by bioinformatic prediction. We also characterized the phenotype regarding cell proliferation, cell migration, and cell invasion in EOC cells lines with altered expression levels of both miR-381 and its target gene, YY1. The expression levels of miR-381 were downregulated in EOC tissues and cell lines. Overexpression of miR-381 significantly inhibited EOC cell proliferation, migration, and invasion. Restoration of YY1 expression partially reversed the phenotype induced by miR-381 overexpression. Knockdown of miR-381 target gene, YY1, mimicked the phenotype induced by miR-381 overexpression. MiR-381 regulated EOC cell through miR-381/YY1/p53 and miR-381/YY1/Wnt signaling axis. We concluded that miR-381 inhibited EOC cell proliferation, migration, and invasion, at least in part, via suppressing YY1 expression.

Role of the Wnt/β-catenin pathway in gastric cancer: An in-depth literature review

Gastric cancer remains one of the most common cancers worldwide and one of the leading cause for cancer-related deaths. Gastric adenocarcinoma is a multifactorial disease that is genetically, cytologically and architecturally more heterogeneous than other gastrointestinal carcinomas. The aberrant activation of the Wnt/β-catenin signaling pathway is involved in the development and progression of a significant proportion of gastric cancer cases. This review focuses on the participation of the Wnt/β-catenin pathway in gastric cancer by offering an analysis of the relevant literature published in this field. Indeed, it is discussed the role of key factors in Wnt/β-catenin signaling and their downstream effectors regulating processes involved in tumor initiation, tumor growth, metastasis and resistance to therapy. Available data indicate that constitutive Wnt signalling resulting from Helicobacter pylori infection and inactivation of Wnt inhibitors (mainly by inactivating mutations and promoter hypermethylation) play an important role in gastric cancer. Moreover, a number of recent studies confirmed CTNNB1 and APC as driver genes in gastric cancer. The identification of specific membrane, intracellular, and extracellular components of the Wnt pathway has revealed potential targets for gastric cancer therapy. High-throughput “omics” approaches will help in the search for Wnt pathway antagonist in the near future.

rs2294008T, a risk allele for gastric and gallbladder cancers, suppresses the PSCA promoter by recruiting the transcription factor YY1

Previous genomewide association studies identified prostate stem cell antigen (PSCA) as a gastric cancer (GC) susceptibility gene and showed an association between GC and the T allele of the single nucleotide polymorphism rs2294008 (C/T) in this gene. The protein product of this gene inhibits cell growth, and the T allele significantly suppresses the transcriptional activity of the -3.2 kb PSCA upstream region. However, the mechanism remains unknown. In this study, we conducted reporter assays using the PSCA upstream region containing the C allele and identified the region from -200 to +38 bp of the transcription initiation site of the gene as a critical region of the -3.2 kb PSCA upstream region. We found that introducing the T allele at rs2294008 generated a consensus binding sequence for the Polycomb group transcription factor Yin Yang 1 (YY1) and that disruption of the consensus sequence restored the transcriptional activity to the -3.2 kb PSCA upstream region. These findings imply that the T allele significantly suppresses PSCA expression in vivo by recruiting YY1 to its promoter, which eventually predisposes gastric epithelial cells to GC development.