Addiction of pancreatic cancer cells to zinc-finger transcription factor ZIC2

Transcription factor ZIC2 regulates the tumorigenic phenotypes associated with both bulk and cancer stem cells in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy in North America. Current therapeutic regimens are ineffective against advanced EOC. A better understanding of the molecular mechanisms that regulate the biology of EOC will be a critical step toward developing more efficacious therapies against EOC. Herein, we demonstrate that elevated expression of transcription factor ZIC2 was associated with lower survival of EOC patients. Knockout of endogenous ZIC2 in EOC cells attenuated the tumorigenic phenotypes associated with both bulk and cancer stem cells in vitro and in vivo, indicating a pro-tumorigenic role of ZIC2 in EOC. On the other hand, however, overexpression of ZIC2 in EOC cells that do not express endogenous ZIC2 promoted cell migration and sphere formation, but inhibited cell growth and colony formation in vitro and tumor growth in vivo, indicating that the role for ZIC2 in EOC is context dependent. Our transcriptomic analysis showed that ZIC2-regulated genes were involved in multiple biological processes and signaling pathways associated with tumor progression. In conclusion, our findings reveal a context-dependent role for ZIC2 in regulating tumorigenic phenotypes in EOC, providing evidence that ZIC2 can be a potential therapeutic target for EOCs that express a high level of ZIC2.

The prognostic value of cancer stage-associated genes in clear cell renal cell carcinoma

OBJECTIVES

Clear cell renal cell carcinoma (ccRCC) is a highly prevalent subtype of malignant renal tumor, but unfortunately, the survival rate remains unsatisfactory. The aim of the present study is to explore genomic features that are correlated with cancer stage, allowing for the identification of subgroups of ccRCC patients with high risk of unfavorable outcomes and enabling prompt intervention and treatment.

METHODS

We compared the gene expression levels across ccRCC patients with diverse cancer stages from The Cancer Genome Atlas (TCGA) database, which revealed characteristic genes associated with tumor stage. We then extracted prognostic genes and used least absolute shrinkage selection operator (LASSO) regression to select four genes for feature extraction and the construction of a prognostic risk model.

RESULTS

We have identified a total of 171 differentially expressed genes (DEGs) that are closely linked to the tumor stage of ccRCC through difference analysis. A prognostic risk model constructed based on the expression levels of ZIC2, TFAP2A-AS1, ITPKA, and SLC16A12 holds significant prognostic value in ccRCC. The results of the functional enrichment analysis imply that the DEGs are mainly involved in the regulation of immune-related signaling pathways, and therefore may have a significant function in immune system regulation of ccRCC.

CONCLUSIONS

Our study has successfully identified significant DEGs between high- and low-staging groups of ccRCC using bioinformatics methods. The construction of a prognostic risk model based on the expression levels of ZIC2, TFAP2A-AS1, ITPKA, and SLC16A12 has displayed promising prognostic significance, indicating its valuable potential for clinical application.

CD70 and PD-L1 (CD274) co-expression predicts poor clinical outcomes in patients with pleural mesothelioma

Diffuse pleural mesothelioma (PM) is a highly aggressive tumour typically associated with short survival. Recently, the effectiveness of first-line immune checkpoint inhibitors in patients with unresectable PM was reported. CD70-CD27 signalling plays a co-stimulatory role in promoting T cell expansion and differentiation through the nuclear factor κB (NF-κB) pathway. Conversely, the PD-L1 (CD274)-PD-1 (PDCD1) pathway is crucial for the modulation of immune responses in normal conditions. Nevertheless, pathological activation of both the CD70-CD27 and PD-L1-PD-1 pathways by aberrantly expressed CD70 and PD-L1 participates in the immune evasion of tumour cells. In this study, 171 well-characterised PMs including epithelioid (n = 144), biphasic (n = 15), and sarcomatoid (n = 12) histotypes were evaluated immunohistochemically for CD70, PD-L1, and immune cell markers such as CD3, CD4, CD8, CD56, PD-1, FOXP3, CD68, and CD163. Eight percent (14/171) of mesotheliomas simultaneously expressed CD70 and PD-L1 on the tumour cell membrane. PMs co-expressing CD70 and PD-L1 contained significantly higher numbers of CD8+ (p = 0.0016), FOXP3+ (p = 0.00075), and CD163+ (p = 0.0011) immune cells within their microenvironments. Overall survival was significantly decreased in the cohort of patients with PM co-expressing CD70 and PD-L1 (p < 0.0001). In vitro experiments revealed that PD-L1 and CD70 additively enhanced the motility and invasiveness of PM cells. In contrast, PM cell proliferation was suppressed by PD-L1. PD-L1 enhanced mesenchymal phenotypes such as N-cadherin up-regulation. Collectively, these findings suggest that CD70 and PD-L1 both enhance the malignant phenotypes of PM and diminish anti-tumour immune responses. Based on our observations, combination therapy targeting these signalling pathways might be useful in patients with PM.

Aberrant transcription factors in the cancers of the pancreas

Transcription factors (TFs) are essential for proper activation of gene set during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-β/SMAD, WNT/β-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

Methylation Profiling of Specific Genes in Ependymomas

OBJECTIVE

Ependymomas are neuroepithelial tumors of the central nervous system with heterogeneous biology and clinical course. The aim of the present study is to investigate the relationship between the methylation status and clinicopathological parameters in ependymomas.

MATERIAL AND METHOD

DNA methylation status of CDKN2A, RASSF1A, KLF4 and ZIC2 genes were quantitatively analyzed with pyrosequencing in 44 ependymoma tumor tissues. The relationship of methylation profiles with tumor subtype, histological grade and patient age was statistically analyzed.

RESULTS

DNA methylation analyses for CDKN2A revealed no difference in methylation levels. Of the 31 included samples for optimal ZIC2 methylation analysis, 10 were hypermethylated (32.3%) and this change was significantly found in the adult spinal ependymomas (p=0.01). KLF4 hypermethylation was observed in 6 of the overall included 35 samples (17.1%); however, there was no statistically significant relation of the methylation status with tumor subtype, histological grade or age group. RASSF1A hypermethylation was observed in overall 40 included samples with varying methylation levels. Higher levels of hypermethylation were significantly related to the grade 3 histology (p=0.01) and spinal ependymomas (p=0.006). The pediatric cases with grade 3 ependymomas and ependymomas of adulthood showed significantly increased RASSF1A hypermethylation levels (p < 0.001 and p=0.001, respectively).

CONCLUSION

DNA methylation changes are likely to have biological importance in ependymomas. Both ZIC2 and RASSF1A methylation status may be useful parameters in the subclassification of these tumors.

Silencing ZIC2 abrogates tumorigenesis and anoikis resistance of non-small cell lung cancer cells by inhibiting Src/FAK signaling

Aberrant expression of the zinc finger protein (ZIC) family has been extensively reported to contribute to progression and metastasis in multiple human cancers. However, the functional roles and underlying mechanisms of ZIC2 in non-small cell lung cancer (NSCLC) are largely unknown. In this study, ZIC2 expression was evaluated using qRT-PCR, western blot, and immunohistochemistry, respectively. Animal experiments in vivo and functional assays in vitro were performed to investigate the role of ZIC2 in NSCLC. Luciferase assays and chromatin immunoprecipitation (ChIP) were carried out to explore the underlying target involved in the roles of ZIC2 in NSCLC. Here, we reported that ZIC2 was upregulated in NSCLC tissues, and high expression of ZIC2 predicted worse overall and progression-free survival of NSCLC patients. Silencing ZIC2 repressed tumorigenesis and reduced the anoikis resistance of NSCLC cells. Mechanical investigation further revealed that silencing ZIC2 transcriptionally inhibited Src expression and inactivated steroid receptor coactivator/focal adhesion kinase signaling, which further attenuated the anoikis resistance of NSCLC cells. Importantly, our results showed that the number of circulating tumor cells (CTCs) was positively correlated with ZIC2 expression in NSCLC patients. Collectively, our findings unravel a novel mechanism implicating ZIC2 in NSCLC, which will facilitate the development of anti-tumor strategies in NSCLC.

Non-coding RNAs related to angiogenesis in gynecological cancer

Gynecological cancer affects the female reproductive system, including ovarian, uterine, endometrial, cervical, vulvar, and vaginal tumors. Non-coding RNAs (ncRNAs), and in particular microRNAs, function as regulatory molecules, which can control gene expression in a post-transcriptional manner. Normal physiological processes like cellular proliferation, differentiation, and apoptosis, and pathological processes such as oncogenesis and metastasis are regulated by microRNAs. Numerous reports have shown a direct role of microRNAs in the modulation of angiogenesis in gynecological cancer, via targeting pro-angiogenic factors and signaling pathways. Understanding the molecular mechanism involved in the regulation of angiogenesis by microRNAs may lead to new treatment options. Recently the regulatory role of some long non-coding RNAs in gynecological cancer has also been explored, but the information on this function is more limited. The aim of this article is to explore the pathways responsible for angiogenesis, and to what extent ncRNAs may be employed as biomarkers or therapeutic targets in gynecological cancer.

Zic Family Member 2 (ZIC2): a Potential Diagnostic and Prognostic Biomarker for Pan-Cancer

Background: As a transcription factor, Zinc finger protein ZIC2 can interact with various DNAs and proteins. Current studies have shown that ZIC2 plays an oncogene role in various cancers. In this study, we systematically characterize the prevalence and predictive value of ZIC2 expression across multiple cancer types. Methods: We mined several public databases, including Oncomine, the Cancer Genome Atlas (TCGA), cBioPortal, Kaplan-Meier Plotter and PrognoScan to evaluated the differentially expressed ZIC2 between tumor samples and normal control samples in pan-cancner, and then explored the association between ZIC2 expression and patient survival, prognosis and clinicopathologic stage. We also analyzed the relationship between tumor mutation burden (TMB), microsatellite instability (MSI), tumor microenvironment, tumor- and immune-related genes and ZIC2 expression. Finally, we explored the potential signaling pathway mechanism through gene set enrichment analysis (GSEA). Results: ZIC2 expression was higher in most cancer tissues compared with adjacent normal tissues. High ZIC2 expression was associated with worse prognosis and a higher clinicopathologic stage. ZIC2 expression was strongly associated with the TMB, MSI, tumor microenvironment and tumor- and immune-related genes. The GSEA revealed that multiple tumor- and immune-related pathways were differentially enriched in ZIC2 high or low expression phenotype. Conclusion: ZIC2 expression may be a potential prognostic molecular biomarker of poor survival in pan-cancer and may act as an oncogene with a strong effect in the processes of tumorigenesis and progression.

Hedgehog Signaling: Implications in Cancers and Viral Infections

The hedgehog (SHH) signaling pathway is primarily involved in embryonic gut development, smooth muscle differentiation, cell proliferation, adult tissue homeostasis, tissue repair following injury, and tissue polarity during the development of vertebrate and invertebrate organisms. GLIoma-associated oncogene homolog (GLI) family of zinc-finger transcription factors and smoothened (SMO) are the signal transducers of the SHH pathway. Both SHH ligand-dependent and independent mechanisms activate GLI proteins. Various transcriptional mechanisms, posttranslational modifications (phosphorylation, ubiquitination, proteolytic processing, SUMOylation, and acetylation), and nuclear-cytoplasmic shuttling control the activity of SHH signaling pathway proteins. The dysregulated SHH pathway is associated with bone and soft tissue sarcomas, GLIomas, medulloblastomas, leukemias, and tumors of breast, lung, skin, prostate, brain, gastric, and pancreas. While extensively studied in development and sarcomas, GLI family proteins play an essential role in many host-pathogen interactions, including bacterial and viral infections and their associated cancers. Viruses hijack host GLI family transcription factors and their downstream signaling cascades to enhance the viral gene transcription required for replication and pathogenesis. In this review, we discuss a distinct role(s) of GLI proteins in the process of tumorigenesis and host-pathogen interactions in the context of viral infection-associated malignancies and cancers due to other causes. Here, we emphasize the potential of the Hedgehog (HH) pathway targeting as a potential anti-cancer therapeutic approach, which in the future could also be tested in infection-associated fatalities.

Emerging Cancer Epigenetic Mechanisms Regulated by All-Trans Retinoic Acid

All-trans retinoic acid (RA), which is the dietary bioactive derivative obtained from animal (retinol) and plant sources (beta-carotene), is a physiological lipid signal of both embryonic and postembryonic development. During pregnancy, either RA deficiency or an excessive RA intake is teratogenic. Too low or too high RA affects not only prenatal, but also postnatal, developmental processes such as myelopoiesis and mammary gland morphogenesis. In this review, we mostly focus on emerging RA-regulated epigenetic mechanisms involving RA receptor alpha (RARA) and Annexin A8 (ANXA8), which is a member of the Annexin family, as well as ANXA8 regulatory microRNAs (miRNAs). The first cancer showing ANXA8 upregulation was reported in acute promyelocytic leukemia (APL), which induces the differentiation arrest of promyelocytes due to defective RA signaling caused by RARA fusion genes as the PML-RARA gene. Over the years, ANXA8 has also been found to be upregulated in other cancers, even in the absence of RARA fusion genes. Mechanistic studies on human mammary cells and mammary glands of mice showed that ANXA8 upregulation is caused by genetic mutations affecting RARA functions. Although not all of the underlying mechanisms of ANXA8 upregulation have been elucidated, the interdependence of RA-RARA and ANXA8 seems to play a relevant role in some normal and tumorigenic settings.

Systematized reporter assays reveal ZIC protein regulatory abilities are Subclass-specific and dependent upon transcription factor binding site context

The ZIC proteins are a family of transcription regulators with a well-defined zinc finger DNA-binding domain and there is evidence that they elicit functional DNA binding at a ZIC DNA binding site. Little is known, however, regarding domains within ZIC proteins that confer trans-activation or -repression. To address this question, a new cell-based trans-activation assay system suitable for ZIC proteins in HEK293T cells was constructed. This identified two previously unannotated evolutionarily conserved regions of ZIC3 that are necessary for trans-activation. These domains are found in all Subclass A ZIC proteins, but not in the Subclass B proteins. Additionally, the Subclass B proteins fail to elicit functional binding at a multimerised ZIC DNA binding site. All ZIC proteins, however, exhibit functional binding when the ZIC DNA binding site is embedded in a multiple transcription factor locus derived from ZIC target genes in the mouse genome. This ability is due to several domains, some of which are found in all ZIC proteins, that exhibit context dependent trans-activation or -repression activity. This knowledge is valuable for assessing the likely pathogenicity of variant ZIC proteins associated with human disorders and for determining factors that influence functional transcription factor binding.

The tumor-suppressive role of microRNA-873 in nasopharyngeal carcinoma correlates with downregulation of ZIC2 and inhibition of AKT signaling pathway

Cancer stem cells (CSCs) are responsible for tumor initiation, relapse, and metastasis. Thus, residual CSCs after chemotherapy may result in poor prognosis for nasopharyngeal carcinoma (NPC). Emerging evidence suggests that differentially expressed microRNAs (miRNAs) regulate genes that carry out important functions in CSCs. Here we investigate the interaction of microRNA-873 (miR-873) with the Zic family member 2 (ZIC2) and the effects on downstream serine-threonine protein kinase (AKT) signaling pathway in CSCs in the context of NPC. Initially, microarray-based gene expression profiling identified ZIC2 as a key differentially expressed gene in NPC, which was subsequently confirmed to be upregulated in clinical NPC tissue samples. NPC cells were subjected to sphere-formation conditions in low-attachment plates, followed by sorting of CD133⁺ cells, which were selected as NPC stem cells after further characterization of stem cell biomarkers. ZIC2 was then shown to be enriched in NPC stem cells at both mRNA and protein levels. However, loss of ZIC2 was associated with the self-renewal, proliferative and tumorigenic properties of NPC stem cells. Next, miRNAs potentially able to target ZIC2 were predicted by the intersection of mirDIP and TargetScan database results, and miRNA miR-873 was found to be downregulated in NPC tissues in general but especially in NPC stem cells. Upregulation of miR-873 inhibited the stem-like properties and tumorigenicity of NPC stem cells, which was found to take place through downregulation of ZIC2 and disruption of the AKT signaling pathway. Collectively, the results obtained suggest that overexpression of miR-873 could aid NPC tumor suppression through reduction of the malignant potential of CSCs.

Construction and validation of a seven-gene signature for predicting overall survival in patients with kidney renal clear cell carcinoma via an integrated bioinformatics analysis

Kidney renal clear cell carcinoma (KIRC) remains a significant challenge worldwide because of its poor prognosis and high mortality rate, and accurate prognostic gene signatures are urgently required for individual therapy. This study aimed to construct and validate a seven-gene signature for predicting overall survival (OS) in patients with KIRC. The mRNA expression profile and clinical data of patients with KIRC were obtained from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC). Prognosis-associated genes were identified, and a prognostic gene signature was constructed. Then, the prognostic efficiency of the gene signature was assessed. The results obtained using data from the TCGA were validated using those from the ICGC and other online databases. Gene set enrichment analyses (GSEA) were performed to explore potential molecular mechanisms. A seven-gene signature (PODXL, SLC16A12, ZIC2, ATP2B3, KRT75, C20orf141, and CHGA) was constructed, and it was found to be effective in classifying KIRC patients into high- and low-risk groups, with significantly different survival based on the TCGA and ICGC validation data set. Cox regression analysis revealed that the seven-gene signature had an independent prognostic value. Then, we established a nomogram, including the seven-gene signature, which had a significant clinical net benefit. Interestingly, the seven-gene signature had a good performance in distinguishing KIRC from normal tissues. GSEA revealed that several oncological signatures and GO terms were enriched. This study developed a novel seven-gene signature and nomogram for predicting the OS of patients with KIRC, which may be helpful for clinicians in establishing individualized treatments.

The level of zinc finger of the cerebellum 2 is predictive of overall survival in clear cell renal cell carcinoma

Background

The zinc finger of the cerebellum 2 (ZIC2) has been reported to function as an oncogenic transcription factor. However, the level and prognostic value of ZIC2 in patients with clear cell renal cell carcinoma (ccRCC) remain unclear.

Methods

UALCAN was employed to analyze the level of ZIC2 mRNA in ccRCC samples compared to normal kidney tissues and to explore the impacts of ZIC2 expression according to tumor-node-metastasis (TNM) stages and histologic grades. The correlations between ZIC2 expression and clinicopathological parameters were investigated by bioinformatic analysis using UCSC Xena Browser in the light of data from The Cancer Genome Atlas. We used Kaplan-Meier analysis to assess the association between the level of ZIC2 and overall survival (OS), disease-free survival (DFS) in ccRCC patients. Moreover, Cox analyses were adopted to evaluate its prognostic value in ccRCC patients.

Results

ZIC2 expression was much higher in ccRCC samples than that in normal ones and increased with the escalation of TNM stages and histologic grades. In addition, the high ZIC2 expression group had significantly advanced age (age >65), T, N, M, TNM stage, histologic grade and lower 5-years OS (19.40% vs. 31.74%, P=0.006) than the low one. High ZIC2 expression was related to remarkably worse OS (P<0.001) in ccRCC patients, whereas no statistical relation was detected between the level of ZIC2 and DFS. Moreover, multivariate analysis indicated high level of ZIC2 is an independent factor of prognosis for worse OS (HR: 1.625, 95% CI, 1.146-2.302, P=0.006).

Conclusions

The level of ZIC2 expression is an independent predictor for OS in ccRCC patients.

Chronic exposure to cadmium induces a malignant transformation of benign prostate epithelial cells

Epidemiological evidence suggests that cadmium (Cd) is one of the causative factors of prostate cancer, but the effect of Cd on benign prostatic hyperplasia (BPH) remains unclear. This study aimed to determine whether Cd exposure could malignantly transform BPH1 cells and, if so, to dissect the mechanism of action. We deciphered the molecular signaling responsible for BPH1 transformation via RNA-sequencing and determined that Cd induced the expression of zinc finger of the cerebellum 2 (ZIC2) in BPH1 cells. We noted Cd exposure increased ZIC2 expression in the Cd-transformed BPH1 cells that in turn promoted anchorage-independent spheroids and increased expression of stem cell drivers, indicating their role in stem cell renewal. Subsequent silencing of ZIC2 expression in transformed cells inhibited spheroid formation, stem cell marker expression, and tumor growth in nude mice. At the molecular level, ZIC2 interacts with the glioma-associated oncogene family (GLI) zinc finger 1 (GLI1), which activates prosurvival factors (nuclear factor NFκB, B-cell lymphoma-2 (Bcl2), as well as an X-linked inhibitor of apoptosis protein (XIAP)) signaling in Cd-exposed BPH1 cells. Conversely, overexpression of ZIC2 in BPH1 cells caused spheroid formation confirming the oncogenic function of ZIC2. ZIC2 activation and GLI1 signaling induction by Cd exposure in primary BPH cells confirmed the clinical significance of this oncogenic function. Finally, human BPH specimens had increased ZIC2 versus adjacent healthy tissues. Thus, we report direct evidence that Cd exposure induces malignant transformation of BPH via activation of ZIC2 and GLI1 signaling.

CD70 expression correlates with a worse prognosis in malignant pleural mesothelioma patients via immune evasion and enhanced invasiveness

Diffuse malignant mesothelioma of the pleura (MPM) is a highly aggressive tumour that typically is associated with short survival. CD70 and CD27 belong to the tumour necrosis factor (TNF) and the TNF receptor (TNFR) superfamily, respectively. Under physiological conditions, the tightly regulated interaction between CD70 and CD27 plays a co-stimulatory role in promoting T-cell expansion and differentiation through the NFκB pathway. Aberrantly high CD70 expression has been documented in haematological and solid malignancies in association with immune evasion in malignant cells. In this study, 172 well-characterised primary diffuse MPM tumours including epithelioid (n = 145), biphasic (n = 15), and sarcomatoid (n = 12) histotypes were evaluated immunohistochemically for CD70, CD27, CD3, CD4, CD8, CD56, PDCD1 (PD-1), and FOXP3 expression. Twenty per cent (34/172) of the mesothelioma cells expressed CD70 on the cell membrane. Overall survival was significantly decreased in the cohort of patients with CD70-expressing tumour cells (p < 0.01). Patients with MPM containing a higher number of CD3+ (p < 0.01), CD4+ (p < 0.01), CD8+ (p < 0.01), or FOXP3+ (p < 0.01) tumour-infiltrating lymphoid cells (TILs) showed significantly worse clinical outcomes. As potential independent risk factors for MPM patients, multivariate Cox proportional hazards regression analysis revealed CD70 expression on mesothelioma cells [hazard ratio (HR) 2.25; p = 0.010], higher FOXP3+ TILs (HR 2.81; p = 0.004), and higher CD3+ TIL accumulation (HR 6.12; p < 0.001). In contrast, as a potential independent favourable factor, higher CD27+ TIL accumulation (HR 0.48; p = 0.037) was identified. In vitro experiments and an immunodeficient mouse model revealed that CD70 enhances the invasiveness of MPM cells through MET-ERK axis activation. Further analyses in syngeneic mouse models demonstrated possible roles for CD70 in immune evasion. Collectively, these findings suggest that the CD70-CD27 pathway enhances the malignant phenotypes of MPM and diminishes anti-tumor immune response in patients with these neoplasms. These markers might be useful in MPM for prognostic evaluations as well as targeted therapeutics. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Diffuse mesothelin expression leads to worse prognosis through enhanced cellular proliferation in colorectal cancer

Mesothelin (MSLN) is a glycophosphatidylinositol (GPI)-linked cell surface protein that is highly expressed in several types of malignant tumor, including malignant pleural mesothelioma, ovarian cancer and pancreatic adenocarcinoma. Recently, a comprehensive immunohistochemical study using MN-1 monoclonal antibody identified a significant number of colorectal tumors in which MSLN was expressed. However, the clinicopathological profiles and survival of patients with MSLN-positive colorectal cancer have not been fully analyzed. In the current study, the expression of MSLN in 270 primary and 44 metastatic colorectal tumors was immunohistochemically analyzed to determine the clinical usefulness of MSLN immunohistochemistry and to identify potential candidates for future anti-MSLN therapy. In vitro experiments using colon cancer cell lines were performed to investigate the biological significance of MSLN expression in tumors. The results of univariate analyses identified a significant correlation between MSLN expression and females (P=0.0042). Furthermore, an inverse correlation between MSLN expression and solid/sheet-like proliferation (P=0.014) was also revealed. Additionally, overall survival was significantly shorter in patients with diffuse luminal/membranous expression of MSLN (P=0.018). Multivariable Cox hazards regression analysis revealed diffuse MSLN expression (hazard ratio, 2.26; 95% confidence interval, 1.04-4.91; P=0.039) as a potential risk factor. When comparing primary CRCs and the metastasis of each, a weakly positive correlation was identified for MSLN positivity (% positive cells; R=0.484; P<0.0001). The in vitro experiments revealed a positive role for MSLN in colon cancer cell proliferation. Thus, MSLN immunohistochemistry may be useful in the prognostication of patients with CRC. The results demonstrated that significant numbers of patients with MSLN-positive CRC exhibiting metastasis could be targeted by anti-MSLN therapies.

MicroRNA-129-5p suppresses nasopharyngeal carcinoma lymphangiogenesis and lymph node metastasis by targeting ZIC2

PURPOSE

The etiology of nasopharyngeal carcinoma (NPC) is multifactorial, complex and not fully characterized yet. MicroRNAs (miRNAs or miRs) have been found to contribute to the development and progression of NPC. Here, we aimed to investigate the putative role of miR-129-5p in NPC lymphangiogenesis and lymph node metastasis (LNM), including the involvement of its target gene ZIC2 and the Hedgehog signaling pathway.

METHODS

The expression of miR-129-5p and ZIC2 in primary NPC tissues was assessed using RT-qPCR and Western blot analyses, followed by LNM and lymph vessel density (LVD) correlation analyses. A direct interaction between miR-129-5p and ZIC2 was verified using a dual-luciferase reporter assay. Gain- and loss-of-function experiments were conducted to investigate the effects of miR-129-5p and ZIC2 expression on NPC cell invasion, migration and proliferation in vitro, as well as on LDV and LNM in nude mice in vivo. Additionally, RT-qPCR and Western blot analyses were performed to determine the expression levels of Hedgehog signaling pathway-related factors.

RESULTS

We found that ZIC2 was highly expressed, and miR-129-5p was lowly expressed, in primary NPC tissues. In addition, we found that miR-129-5p can directly bind to and reduce ZIC2 expression. LVD was found to be negatively correlated with miR-129-5p and to be positively correlated with ZIC2 expression. Concomitantly, we found that miR-129-5p abrogated activation of the Hedgehog signaling pathway via ZIC2 targeting, leading to suppression of NPC cell invasion, migration and proliferation in vitro as well as suppression of LNM and LVD in vivo.

CONCLUSIONS

From our data we conclude that miR-129-5p, by decreasing ZIC2 expression, may inhibit NPC lymphangiogenesis and LNM through suppression of the Hedgehog signaling pathway.

Zinc finger of the cerebellum 5 promotes colorectal cancer cell proliferation and cell cycle progression through enhanced CDK1/CDC25c signaling

Introduction

Colorectal cancer (CRC), mostly caused by external or environmental factors, is the third most common and lethal cancer worldwide. Although a large number of investigations have been carried out to reveal the evolution of CRC, the underlying mechanisms of CRC remain unclear.

Material and methods

Expression of zinc finger of the cerebellum 5 (ZIC5) in CRC tissues and cell models was measured by qRT-PCR and IHC. Cell transfection was carried out for ZIC5 overexpression or knockdown. The MTT assay was applied to examine the capacity of glioma cell proliferation. Wound healing assay and tumor invasion assay were used to test the capacity of glioma cell migration and invasion respectively. Cell cycle analysis and western blot were used to verify the apoptosis rates of CRC cells upon ZIC5 overexpression or downregulation. A further tumor Xenograft study was used to examine the effects of ZIC5 on tumor malignancy in vivo.

Results

Cell models using HCT116 and SW620 cells were established to study the ZIC5 function upon ZIC5 overexpression of knockdown. Consistently, we discovered that ZIC5 also significantly increased in Chinese CRC patients. In addition, ZIC5 promoted CRC cell proliferation through increasing the proportion of cells maintained in the S phase. ZIC5 overexpression facilitated the capacity of CRC cell migration and invasion. Inhibition of ZIC5 mitigated such malignant effects.

Conclusions

Collectively, investigations of the ZIC5 in CRC provided a new insight into CRC diagnosis, treatment, prognosis and next-step translational therapeutic developments from bench to clinic.

Random forest-based modelling to detect biomarkers for prostate cancer progression

BACKGROUND

The clinical course of prostate cancer (PCa) is highly variable, demanding an individualized approach to therapy. Overtreatment of indolent PCa cases, which likely do not progress to aggressive stages, may be associated with severe side effects and considerable costs. These could be avoided by utilizing robust prognostic markers to guide treatment decisions.

RESULTS

We present a random forest-based classification model to predict aggressive behaviour of prostate cancer. DNA methylation changes between PCa cases with good or poor prognosis (discovery cohort with n = 70) were used as input. DNA was extracted from formalin-fixed tumour tissue, and genome-wide DNA methylation differences between both groups were assessed using Illumina HumanMethylation450 arrays. For the random forest-based modelling, the discovery cohort was randomly split into a training (80%) and a test set (20%). Our methylation-based classifier demonstrated excellent performance in discriminating prognosis subgroups in the test set (Kaplan-Meier survival analyses with log-rank p value < 0.0001). The area under the receiver operating characteristic curve (AUC) for the sensitivity analysis was 95%. Using the ICGC cohort of early- and late-onset prostate cancer (n = 222) and the TCGA PRAD cohort (n = 477) for external validation, AUCs for sensitivity analyses were 77.1% and 68.7%, respectively. Cancer progression-related DNA hypomethylation was frequently located in 'partially methylated domains' (PMDs)-large-scale genomic areas with progressive loss of DNA methylation linked to mitotic cell division. We selected several candidate genes with differential methylation in gene promoter regions for additional validation at the protein expression level by immunohistochemistry in > 12,000 tissue micro-arrayed PCa cases. Loss of ZIC2 protein expression was associated with poor prognosis and correlated with significantly shorter time to biochemical recurrence. The prognostic value of ZIC2 proved to be independent from established clinicopathological variables including Gleason grade, tumour stage, nodal stage and prostate-specific-antigen.

CONCLUSIONS

Our results highlight the prognostic relevance of methylation loss in PMD regions, as well as of several candidate genes not previously associated with PCa progression. Our robust and externally validated PCa classification model either directly or via protein expression analyses of the identified top-ranked candidate genes will support the clinical management of prostate cancer.

A three-gene novel predictor for improving the prognosis of cervical cancer

Cervical cancer is the most common gynecological malignancy, the third most common malignant tumor in women worldwide, and the most common malignant tumor among Chinese women. However, despite continuous improvement in medical treatment, the number of cervical cancer cases in China is on the increase annually, consistent with the general trend in global cervical cancer incidence. Therefore, it is particularly important to study the pathogenesis of cervical cancer at the genetic level in China. The aim of the present study was to use the TCGA database to identify potential genetic signatures that could predict the prognosis of patients with cervical cancer and provide evidence supporting clinical genetic intervention in cervical cancer. Primarily, an effective three-gene signature was found that predicts prognosis in patients with cervical cancer. This model can provide prima facie evidence for future assessment of patient risk and prognosis, but further testing is required to improve its accuracy. Our results also suggested that centromere protein M, methionine sulfoxide reductase B3 and Zic family member 2 could be promising biomarkers for the prognosis of cervical cancer.

Annexin A8 can serve as potential prognostic biomarker and therapeutic target for ovarian cancer: based on the comprehensive analysis of Annexins

BACKGROUND

Annexins are involved in vesicle trafficking, cell proliferation and apoptosis, but their functional mechanisms in ovarian cancer remain unclear. In this study, we analyzed Annexins in ovarian cancer using different databases and selected Annexin A8 (ANXA8), which showed the greatest prognostic value, for subsequent validation in immunohistochemical (IHC) assays.

METHODS

The mRNA expression levels, genetic variations, prognostic values and gene-gene interaction network of Annexins in ovarian cancer were analyzed using the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, Kaplan-Meier plotter and GeneMANIA database. ANXA8 was selected for analyzing the biological functions and pathways of its co-expressed genes, and its correlation with immune system responses via the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and the TISIDB database, respectively. We validated the expression of ANXA8 in ovarian cancer via IHC assays and analyzed its correlation with clinicopathological parameters and prognosis.

RESULTS

ANXA2/3/8/11 mRNA expression levels were significantly upregulated in ovarian cancer, and ANXA5/6/7 mRNA expression levels were significantly downregulated. Prognostic analysis suggested that significant correlations occurred between ANXA2/4/8/9 mRNA upregulation and poor overall survival, and between ANXA8/9/11 mRNA upregulation and poor progression-free survival in patients with ovarian serous tumors. Taken together, results suggested that ANXA8 was most closely associated with ovarian cancer tumorigenesis and progression. Further analyses indicated that ANXA8 may be involved in cell migration, cell adhesion, and vasculature development, as well as in the regulation of PI3K-Akt, focal adhesion, and proteoglycans. Additionally, ANXA8 expression was significantly correlated with lymphocytes and immunomodulators. The IHC results showed that ANXA8 expression was higher in the malignant tumor group than in the borderline and benign tumor groups and normal ovary group, and high ANXA8 expression was an independent risk factor for survival and prognosis of ovarian cancer patients (P = 0.013).

CONCLUSIONS

Members of the Annexin family display varying degrees of abnormal expressions in ovarian cancer. ANXA8 was significantly highly expressed in ovarian cancer, and high ANXA8 expression was significantly correlated with poor prognosis. Therefore, ANXA8 is a high candidate as a novel biomarker and therapeutic target for ovarian cancer.

β-Catenin/Tcf7l2-dependent transcriptional regulation of GLUT1 gene expression by Zic family proteins in colon cancer

The zinc finger of the cerebellum (ZIC) proteins has been implicated to function in normal tissue development. Recent studies have described the critical functions of Zic proteins in cancers and the potential tumor-suppressive functions in colon cancer development and progression. To elucidate the functional roles of Zic proteins in colorectal cancer, we knocked out the Zic5 gene and analyzed the chromatin localization pattern and transcriptional regulation of target gene expression. We found that Zic5 regulates glucose metabolism, and Zic5 knockout is accompanied by an increased glycolytic state and tolerance to a low-glucose condition. Furthermore, loss of β-catenin or TCF7l2 diminishes the chromatin binding of Zic5 globally. Our studies suggest that the Wnt/β-catenin signaling pathway has a strong influence on the function of Zic proteins and glucose metabolism in colorectal cancers through GLUT1. Interfering Wnt/-catenin-Zic5 axis-regulated aerobic glycolysis represents a potentially effective strategy to selectively target colon cancer cells.

miR‑1271‑5p inhibits cell proliferation and induces apoptosis in acute myeloid leukemia by targeting ZIC2

MicroRNAs (miRNAs) have been demonstrated to regulate the progression of numerous types of cancer, including acute myeloid leukemia (AML). Previous studies demonstrated that miR‑1271‑5p functions as a tumor suppressor; however, the roles of miR‑1271‑5p in AML remain unknown. In the present study, miR‑1271‑5p was significantly downregulated in AML tissues compared with normal tissues by reverse transcription‑quantitative polymerase chain reaction analysis. Furthermore, the expression levels of miR‑1271‑5p in patients with AML may function as a prognostic marker. In addition, overexpression of miR‑1271‑5p significantly suppressed the proliferation and induced apoptosis of AML cells by Cell Counting kit‑8 and fluorescence activated cell sorter assays; miR‑1271‑5p downregulation exhibited opposing effects. Additionally, transcription factor ZIC2 may be a direct target of miR‑1271‑5p in AML cells, which was demonstrated by a luciferase reporter assay and RNA pulldown assay. Overexpression of miR‑1271‑5p significantly reduced the mRNA and protein expression levels of ZIC2 in AML193 and OCI‑AML2 cells by reverse transcription‑quantitative polymerase chain reaction analysis and western blotting. Furthermore, an inverse correlation between miR‑1271‑5p and ZIC2 expression in AML samples was observed. In summary, ZIC2 was upregulated in AML tissues, and restoration of ZIC2 expression was able to promote the proliferation and reduce the apoptosis of AML cells transfected with miR‑1271‑5p mimics. The results of the present study demonstrated that miR‑1271‑5p inhibited the progression of AML by targeting ZIC2.

Upregulation of microRNA-129-5p inhibits cell invasion, migration and tumor angiogenesis by inhibiting ZIC2 via downregulation of the Hedgehog signaling pathway in cervical cancer

Recently, some studies have placed additional research focus on microRNAs (miRNAs) in a bid to discover novel therapeutic approaches for cervical cancer (CC), which is one of the most common female reproductive tract malignancies with high rates of morbidity and mortality. Hence, the aim of the present study was to evaluate the ability of miR-129-5p to influence cell angiogenesis, invasion and migration by targeting ZIC2 through the Hedgehog signaling pathway in CC. Both CC and adjacent normal tissues were extracted from 87 eligible participating patients with CC. Measurements of the levels of miR-129-5p, mRNA and protein levels of ZIC2, sonic Hedgehog (Shh), Gli1, and Gli2 and levels of CXCL1, VEGF and Ang2 were determined accordingly. An angiogenesis assay was performed to evaluate cell angiogenesis in vitro, while a scratch test and transwell assay were adopted for cell invasion and migration determination. Lastly, tumor formation within nude mice was performed in order to analyze angiogenesis and tumor growth among the nude mice in vivo. The findings revealed that upregulation of miR-129-5p resulted in the decrease in the mRNA and protein levels of ZIC2, Shh, Gli1, Gli2, as well as reduced levels of CXCL1, VEGF and Ang2. Moreover, up-regulation of miR-129-5p was determined to inhibit CC cell angiogenesis ability in vitro, in addition to the processes of cell migration, and invasion. Finally, up-regulation of miR-129-5p was observed to inhibit the tumor growth and angiogenesis ability of nude mice in vivo. The results of the present study provided evidence suggesting that overexpressed miR-129-5p prevents angiogenesis and inhibits cell migration and invasion by means of negatively targeting ZIC2 through suppression of the Hedgehog signaling pathway in CC. Thus, highlighting the promise of miR-129-5p as a novel target for treating CC is promising.

The expression status of ZIC2 as a prognostic marker for nasopharyngeal carcinoma

Zinc finger protein ZIC2 is a transcription factor encoded by the ZIC2 gene, which can interact with various DNAs and proteins. ZIC2 expression may promote cell proliferation and inhibit apoptosis. Recent studies have reported that ZIC2 acts as an oncogene in various cancers. The expression and distinct prognostic value of ZIC2 in NPC is not well established. The aim of this study was to investigate ZIC2 expression and its prognostic significance in nasopharyngeal carcinoma (NPC). The ZIC2 expressions at the mRNA levels in NPC tissues and normal tissues were investigated using Oncomine analysis. ZIC2 protein expression was analyzed in paraffin-embedded NPC tissues by immunohistochemistry. Statistical analyses were performed to evaluate the clinicopathological significance of ZIC2 expression. The result shows the expression of ZIC2 mRNA is significantly elevated in NPC tissue compared with normal nasopharynx tissues. In paraffin-embedded tissue samples, the immunoreactivity of ZIC2 was primarily seen in the nuclei and cytoplasms within tumor cells. High ZIC2 expression was obviously related to poor OS and DFS compared to low ZIC2 expression. In a multivariate analysis, the expression of ZIC2 was an independent prognostic factor for OS and DFS. ZIC2 is up-regulated in NPC and associated with histology and survival. ZIC2 may serve as a prognostic indicator for patients with NPC.

A novel molecular mechanism for a long non-coding RNA PCAT92 implicated in prostate cancer

The role of many lncRNAs in cancer remains elusive including that for a Prostate Cancer Associated Transcript 92 (PCAT92). PCAT92 shares the locus on chromosome 13 with ABCC4 gene, known to be implicated in prostate cancer. It has been shown that PCAT92 and ABCC4 are up-regulated in prostate cancer samples from multiple transcriptome datasets. Among the prostate cancer cell-lines LNCaP showed maximum overexpression of PCAT92 compared to control cell-line RWPE-1. We have shown that knockdown of PCAT92 in LNCaP cells reduces cell viability and proliferation and down-regulates ABCC4 transcript/protein expression. The shared region between PCAT92 and ABCC4 has a binding site for an oncogenic transcription factor (ZIC2) which is also upregulated in the majority of datasets studied here. ZIC2 binding to the predicted ABCC4 promoter has been confirmed using pull-down assay. Interestingly, under PCAT92 knockdown condition, there is a reduction in the ZIC2 binding to ABCC4 promoter indicating the potential involvement of PCAT92 in the recruitment of ZIC2. We have identified distinct regions on PCAT92 with potential to bind to ZIC2 non-DNA binding Zinc-finger domain and potential for triplex formation near ABCC4 promoter region, which have been experimentally validated. Together, these observations and localization in the nucleus suggests that PCAT92 may play a role in prostate cancer by increasing the local concentration of ZIC2 by forming RNA-DNA triplex near ABCC4 promoter thus helping in recruitment of ZIC2 for ABCC4 regulation.

Clinicopathologic and Prognostic Significance of the Zinc Finger of the Cerebellum Family in Invasive Breast Cancer

Purpose

Five members of the zinc finger of the cerebellum (ZIC) family-ZIC1, ZIC2, ZIC3, ZIC4, and ZIC5-have been shown to be involved in various carcinomas. Here, we aimed to explore the clinicopathologic and prognostic roles of ZIC family members in invasive breast cancer patients using immunohistochemical analysis, western blotting analysis, and real-time quantitative polymerase chain reaction (RT-qPCR).

Methods

A total of 241 female invasive breast cancer patients who underwent radical mastectomy between 2009 and 2011 were enrolled. ZIC proteins in 241 pairs of breast tumors and corresponding normal tissues were investigated using immunohistochemistry and the clinicopathologic roles of proteins were analyzed using Pearson's chi-square test. Kaplan-Meier curves and Cox regression analysis were also used to analyze the prognostic value of the ZIC proteins. In addition, 12 pairs of fresh-frozen breast tumors and matched normal tissues were used in the western blotting analysis and RT-qPCR.

Results

Only ZIC1 expression in normal tissues was obviously higher than that in tumors (p<0.001). On multivariate analysis, ZIC1 expression (in overall survival analysis: hazard ratio [HR], 0.405, 95% confidence interval [CI], 0.233-0.702, p=0.001; in disease-free survival analysis: HR, 0.395, 95% CI, 0.234-0.669, p=0.001) was identified as a prognostic indicator of invasive breast cancer.

Conclusion

ZIC1, but not the other proteins, was obviously decreased in breast tumors and associated with clinicopathologic factors. Thus, ZIC1 might be a novel indicator to predict the overall and disease-free survival of invasive breast cancer patients.

Long non-coding RNA HULC promotes bladder cancer cells proliferation but inhibits apoptosis via regulation of ZIC2 and PI3K/AKT signaling pathway

BACKGROUND

Bladder cancer is the fourth most common malignancy among men urinary system and it is a complex disease caused by genetic and environmental factors.

OBJECTIVE

This study aimed to evaluate the effects of hepatocellular carcinoma up-regulated long non-coding RNA (lncRNA HULC) on bladder cancer and to reveal the potential mechanisms.

METHODS

The expression level of HULC in 276 bladder cancer patients was detected. The association of HULC level with patient recurrence was performed by Kaplan-Meier and log-rank test. Moreover, T24 and RT4 cells were transfected with HULC and ZIC2 targeted siRNAs, HULC expressing vector and corresponding controls. Subsequently, cell viability, apoptosis and tumorigenesis were examined.

RESULTS

The expression level of HULC was increased in bladder cancer tissues. High expression of HULC was correlated with advanced clinical stage and lower recurrence-free rate. HULC was remarkably promoted cell viability but inhibited apoptosis, meanwhile conspicuously increased the expression of Cyclin A/D1/E and Bcl-2. Xenograft tumor model showed that HULC promoted tumor weights in vivo.

CONCLUSIONS

LncRNA HULC promoted bladder cancer cells proliferation and inhibited apoptosis.

ZIC2 promotes viability and invasion of human osteosarcoma cells by suppressing SHIP2 expression and activating PI3K/AKT pathways

Osteosarcoma is a malignant tumor of the skeletal system. The zinc finger transcription factor ZIC2 has been reported to be highly expressed in human cancers. The present study evaluated the effects of ZIC2 and the possible underlying mechanisms in the human osteosarcoma cells. The expression levels of ZIC2 in human fetal osteoblastic cell line (hFOB1.19), osteosarcoma cell lines (U-2OS, SaoS2, and MG63), normal bone tissue, and osteosarcoma tumor were analyzed by Western blot, and real-time quantitative RT-PCR (qRT-PCR). Osteosarcoma cells with either overexpressed ZIC2 or suppressed ZIC2 were analyzed to determine cell viability, colony formation, and cell invasion. The expressions of SHIP2 and PI3K/AKT signal pathway-related proteins were analyzed by Western blot and qRT-PCR. We first showed that ZIC2 is highly expressed in osteosarcoma cells and tissues. Then we demonstrated that overexpression of ZIC2 promoted viability, migration, and invasion of osteosarcoma cells, whereas suppression of ZIC2 showed opposite effects. Furthermore, SHIP2 expression was negatively regulated by ZIC2. Importantly, ZIC2 overexpression activated the PI3K/AKT signal pathway; however, overexpressed SHIP2 inhibited these effects. Lastly, we showed that activation of the PI3K/AKT signal pathway is essential for the effects of ZIC2 on osteosarcoma cells, as the effects of ZIC2 on the osteosarcoma cells were reversed by a PI3K/AKT inhibitor. Overall, ZIC2 is highly expressed in osteosarcoma cells and tissues, and its overexpression promotes viability, invasion of osteosarcoma cells via SHIP2 suppression, and PI3K/AKT activation. Thus, ZIC2 can be considered as a novel drug target for osteosarcoma management.

ZIC2 Is Essential for Maintenance of Latency and Is a Target of an Immediate Early Protein during Kaposi's Sarcoma-Associated Herpesvirus Lytic Reactivation

Bivalent histone modifications are defined as repressive and activating epigenetic marks that simultaneously decorate the same genomic region. The H3K27me3 mark silences gene expression, while the H3K4me3 mark prevents the region from becoming permanently silenced and prepares the domain for activation when needed. Specific regions of Kaposi's sarcoma-associated herpesvirus (KSHV) latent episomes are poised to be activated by the KSHV replication and transcription activator (K-Rta). How KSHV episomes are prepared such that they maintain latent infection and switch to lytic replication by K-Rta remains unclear. K-Rta transactivation activity requires a protein degradation function; thus, we hypothesized that identification of cellular substrates of K-Rta may provide insight into the maintenance of KSHV latent infection and the switch to lytic replication. Here we show that a zinc finger protein, ZIC2, a key regulator for central nervous system development, is a substrate of K-Rta and is responsible for maintaining latency. K-Rta directly interacted with ZIC2 and functioned as an E3 ligase to ubiquitinate ZIC2. ZIC2 localized at immediate early and early gene cluster regions of the KSHV genome and contributed to tethering of polycomb repressive complex 2 through physical interaction, thus maintaining H3K27me3 marks at the K-Rta promoter. Accordingly, depletion of ZIC2 shifted the balance of bivalent histone modifications toward more active forms and induced KSHV reactivation in naturally infected cells. We suggest that ZIC2 turnover by K-Rta is a strategy employed by KSHV to favor the transition from latency to lytic replication.

IMPORTANCE Posttranslational histone modifications regulate the accessibility of transcriptional factors to DNA; thus, they have profound effects on gene expression (e.g., viral reactivation). KSHV episomes are known to possess bivalent chromatin domains. How such KSHV chromatin domains are maintained to be reactivatable by K-Rta remains unclear. We found that ZIC2, a transcriptional factor essential for stem cell pluripotency, plays a role in maintaining KSHV latent infection in naturally infected cells. We found that ZIC2 degradation by K-Rta shifts bivalent histone marks to a more active configuration, leading to KSHV reactivation. ZIC2 interacts with and maintains polycomb repressor complex 2 at the K-Rta promoter. Our findings uncover (i) a mechanism utilized by KSHV to maintain latent infection, (ii) a latency-lytic cycle switch operated by K-Rta, and (iii) a molecular mechanism of ZIC2-mediated local histone modification.

Histopathological and genotypic characterization of metastatic colorectal carcinoma with PD-L1 (CD274)-expression: Possible roles of tumour micro environmental factors for CD274 expression

Aberrant PD-L1 (CD274) expression has been described in different types of tumour and linked to tumour aggressiveness and a poor prognosis. In primary colorectal carcinomas (CRCs), CD274 expression was reported to be associated with mismatch repair (MMR)-deficiency, BRAF mutation, and "stem-like" immunophenotype defined by down-regulation of homeobox protein CDX2 and membranous expression of activated leukocyte cell adhesion molecule (ALCAM). However, the immunophenotype and genotype of CD274-positive metastatic CRC have not been extensively analysed. In this study, 189 CRC metastases were evaluated immunohistochemically for CD274, MMR proteins, CDX2, and ALCAM expression. Immunostaining for CD4, CD8, and FOXP3 was also performed to characterize tumour-associated immune cells. In addition, 34 arbitrarily selected lesions were genotyped using Sanger- and next-generation sequencing. Univariate analyses showed no clear association between CD274 expression and clinicopathological parameters including MMR-deficiency or "stem-like" immunophenotype after adjustment for multiple testing. Comparison of the clinicopathological profiles of CD274-positive primary and metastatic tumours revealed in the latter younger age of occurrence (60.9 ± 13.3 versus 72.6 ± 13.1 years, p = 0.001), cytoplasm-dominant CD274 expression (p < 0.001), infrequent MMR-deficiency (p < 0.001), and common KRAS mutations (54%, p < 0.001). In five cultured colon cancer cell lines, CD274 was expressed and modulated after exogenous exposure to IFNγ and TGF-β1. Thus, CD274 regulation mechanisms might include tumour micro environmental factors. Based on significantly different characteristics in CD274-positive metastatic and primary CRCs, evaluation of metastases should also be considered when planning immune checkpoint inhibitor therapy.

GLI1, a master regulator of the hallmark of pancreatic cancer

Hedgehog signaling is highly conserved across species and governs proper embryonic development. Germline gene mutations that reduce this signaling activity cause a variety of developmental abnormalities such as holoprosencephaly, while those that enhance Hedgehog signaling activity induce a tumor-predisposition condition Nevoid basal cell carcinoma syndrome. Furthermore, dysregulated activation of Hedgehog signaling has been recognized in various sporadic malignancies, including pancreatic adenocarcinoma. Pancreatic adenocarcinoma develops through a multistep carcinogenesis starting with oncogenic mutation of the KRAS gene. During this process, precancerous or cancer cells secrete Hedgehog ligand proteins to promote characteristic desmoplastic stroma around the cells, which in turn activates the expression of the downstream transcription factor GLI1 inside the cells. The quantitative and spatiotemporal dysregulation of GLI1 subsequently leads to the expression of transcriptional target genes of GLI1 that govern the hallmark of malignant properties. Here, after a brief introductory outline, a perspective is offered of Hedgehog signaling with a special focus on the role of GLI1 in pancreatic carcinogenesis.

Roles of ZIC family genes in human gastric cancer

The human zinc finger of the cerebellum (ZIC)family genes, comprised of 5 members, which are vertebrate homologues of the Drosophila odd-paired gene and encode zinc-finger transcription factors, have been shown to be involved in various diseases, including cancer. However, the roles of ZICs in human gastric cancer (GC) have not yet been fully elucidated. This study aimed to investigate the expression patterns of ZICs and determine their clinical significance in GC. The mRNA and protein expression levels of ZIC1-5 were detected by RT-qPCR and western blot analysis, respectively using 60 pairs of human GC and matched normal mucosa tissues. The expression pattern and subcellular localization of ZIC1 in 160 pairs of human GC and matched normal mucosa tissues were verified by immunohistochemistry. Moreover, the associations of ZIC1 expression with various clinicopathological characteristics and patient prognosis were evaluated. The mRNA and protein expression levels of ZIC1 were both found to be significantly decreased in the GC tissues compared to matched normal mucosa tissues (GC vs. normal, 2.15±0.69 vs. 4.28±0.95; P<0.001); however, ZIC2-5 expression exhibited no significant difference between the cancer and normal tissue samples. In addition, the downregulation of ZIC1 (ZIC1-low) was more frequently observed in the GC tissues with positive lymph node metastasis (P=0.006), an advanced TNM stage (P<0.001) and a great depth of invasion (P=0.01). Notably, a low ZIC1 expression was significantly associated with a poor disease-free and overall survival. Furthermore, multivariate analysis revealed that ZIC1 expression was an independent prognostic marker for patients with GC. In conclusion, among the human ZIC family genes, the dysregulation of ZIC1, but not of ZIC2, ZIC3, ZIC4 and ZIC5, may play a crucial role in the progression of GC. ZIC1 may thus serve as a novel molecular marker to predict the progression, survival and relapse of patients with GC.