Involvement of IFN regulatory factor (IRF)-1 and IRF-2 in the formation and progression of human esophageal cancers

Mechanisms of tumor immunosuppressive microenvironment formation in esophageal cancer

As a highly invasive malignancy, esophageal cancer (EC) is a global health issue, and was the eighth most prevalent cancer and the sixth leading cause of cancer-related death worldwide in 2020. Due to its highly immunogenic nature, emer-ging immunotherapy approaches, such as immune checkpoint blockade, have demonstrated promising efficacy in treating EC; however, certain limitations and challenges still exist. In addition, tumors may exhibit primary or acquired resistance to immunotherapy in the tumor immune microenvironment (TIME); thus, understanding the TIME is urgent and crucial, especially given the im-portance of an immunosuppressive microenvironment in tumor progression. The aim of this review was to better elucidate the mechanisms of the suppressive TIME, including cell infiltration, immune cell subsets, cytokines and signaling pathways in the tumor microenvironment of EC patients, as well as the downregulated expression of major histocompatibility complex molecules in tumor cells, to obtain a better understanding of the differences in EC patient responses to immunotherapeutic strategies and accurately predict the efficacy of immunotherapies. Therefore, personalized treatments could be developed to maximize the advantages of immunotherapy.

microRNA-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation

BACKGROUND

Epigenetic alterations contribute greatly to the development and progression of colorectal cancer, and effect of aberrant miR-622 expression is still controversial. This study aimed to discover miR-622 regulation in CRC proliferation.

METHODS

miR-622 expression and prognosis were analyzed in clinical CRC samples from Nanfang Hospital. miR-622 regulation on cell cycle and tumor proliferation was discovered, and FOLR2 was screened as functional target of miR-622 using bioinformatics analysis, which was validated via dual luciferase assay and gain-of-function and loss-of-function experiments both in vitro and in vivo.

RESULTS

miR-622 overexpression in CRC indicated unfavorable prognosis and it regulated cell cycle to promote tumor growth both in vitro and in vivo. FOLR2 is a specific, functional target of miR-622, which negatively correlates with signature genes in cell cycle process to promote CRC proliferation.

CONCLUSIONS

miR-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation, proposing a novel mechanism and treatment target in CRC epigenetic regulation of miR-622.

IRF5 promotes glycolysis in the progression of hepatocellular carcinoma and is regulated by TRIM35

OBJECTIVES

The interferon regulatory factor (IRF) family of proteins are involved in tumor progression. However, the role of IRF5 in tumorigenesis remains unknown. In this study we aimed to elucidate the functions of IRF5 in the progression of hepatocellular carcinoma (HCC).

METHODS

IRF5 expression in HCC was analyzed through quantitative polymerase chain reaction (qPCR), western blot, and immunohistochemistry (IHC), etc. The Cell Counting Kit 8 (CCK8) assay, anchorage-independent assay, and EdU assay were used to evaluate the role of IRF5. The molecular mechanisms were studied by analyzing the metabolites with mass spectrum and immunoprecipitation.

RESULTS

IRF5 was upregulated in HCC. Interfering with IRF5 inhibited the proliferation and tumorigenic potential of HCC cells. When studying the molecular mechanism, IRF5 was found to upregulate the expression of lactate dehydrogenase A (LDHA) and promoted glycolysis. Additionally, tripartite motif containing 35 (TRIM35) interacted with IRF5, promoting its ubiquitination and degradation. In the clinically obtained HCC samples, TRIM35 was negatively correlated with the expression of IRF5.

CONCLUSION

These findings reveal the oncogenic function of IRF5 in the progression of HCC by enhancing glycolysis, further supporting the potential of IRF5 as a viable target for HCC therapy.

The Roles of Antisense Long Noncoding RNAs in Tumorigenesis and Development through Cis-Regulation of Neighbouring Genes

Antisense long noncoding RNA (as-lncRNA) is a lncRNA transcribed in reverse orientation that is partially or completely complementary to the corresponding sense protein-coding or noncoding genes. As-lncRNAs, one of the natural antisense transcripts (NATs), can regulate the expression of their adjacent sense genes through a variety of mechanisms, affect the biological activities of cells, and further participate in the occurrence and development of a variety of tumours. This study explores the functional roles of as-lncRNAs, which can cis-regulate protein-coding sense genes, in tumour aetiology to understand the occurrence and development of malignant tumours in depth and provide a better theoretical basis for tumour therapy targeting lncRNAs.

Peptide vaccine from cancer-testis antigen ODF2 can potentiate the cytotoxic T lymphocyte infiltration through IL-15 in non-MSI-H colorectal cancer

About 85% of patients with colorectal cancer (CRC) have the non-microsatellite instability-high (non-MSI-H) subtype, and many cannot benefit from immune checkpoint blockade. A potential reason for this is that most non-MSI-H colorectal cancers are immunologically "cold" due to poor CD8⁺ T cell infiltration. In the present study, we screened for potential cancer-testis antigens (CTAs) by comparing the bioinformatics of CD8⁺ T effector memory (Tem) cell infiltration between MSI-H and non-MSI-H CRC. Two ODF2-derived epitope peptides, P433 and P609, displayed immunogenicity and increased the proportion of CD8⁺ T effector memory (Tem) cells in vitro and in vivo. The adoptive transfer of peptide pool-induced CTLs inhibited tumor growth and enhanced CD8⁺ T cell infiltration in tumor-bearing NOD/SCID mice. The mechanistic study showed that knockdown of ODF2 in CRC cells promoted interleukin-15 expression, which facilitated CD8⁺ T cell proliferation. In conclusion, ODF2, a CTA, was negatively correlated with CD8⁺ T cell infiltration in "cold" non-MSI-H CRC and was selected based on the results of bioinformatics analyses. The corresponding HLA-A2 restricted epitope peptide induced antigen-specific CTLs. Immunotherapy targeting ODF2 could improve CTA infiltration via upregulating IL-15 in non-MSI-H CRC. This tumor antigen screening strategy could be exploited to develop therapeutic vaccines targeting non-MSI-H CRC.

The transcription factor IRF2 drives interferon-mediated CD8+ T cell exhaustion to restrict anti-tumor immunity

Type I and II interferons (IFNs) stimulate pro-inflammatory programs that are critical for immune activation, but also induce immune-suppressive feedback circuits that impede control of cancer growth. Here, we sought to determine how these opposing programs are differentially induced. We demonstrated that the transcription factor interferon regulatory factor 2 (IRF2) was expressed by many immune cells in the tumor in response to sustained IFN signaling. CD8+ T cell-specific deletion of IRF2 prevented acquisition of the T cell exhaustion program within the tumor and instead enabled sustained effector functions that promoted long-term tumor control and increased responsiveness to immune checkpoint and adoptive cell therapies. The long-term tumor control by IRF2-deficient CD8+ T cells required continuous integration of both IFN-I and IFN-II signals. Thus, IRF2 is a foundational feedback molecule that redirects IFN signals to suppress T cell responses and represents a potential target to enhance cancer control.

Transcriptional and reverse transcriptional regulation of host genes by human endogenous retroviruses in cancers

Human endogenous retroviruses (HERVs) originated from ancient retroviral infections of germline cells millions of years ago and have evolved as part of the host genome. HERVs not only retain the capacity as retroelements but also regulate host genes. The expansion of HERVs involves transcription by RNA polymerase II, reverse transcription, and re-integration into the host genome. Fast progress in deep sequencing and functional analysis has revealed the importance of domesticated copies of HERVs, including their regulatory sequences, transcripts, and proteins in normal cells. However, evidence also suggests the involvement of HERVs in the development and progression of many types of cancer. Here we summarize the current state of knowledge about the expression of HERVs, transcriptional regulation of host genes by HERVs, and the functions of HERVs in reverse transcription and gene editing with their reverse transcriptase.

A Novel Pyroptosis-Associated Gene Signature to Predict Prognosis in Patients with Colorectal Cancer

Background

Pyroptosis is a form of cell death characterized by cell swelling and plasma membrane bubbling in association with inflammatory and immune responses. To date, the association between pyroptosis and colorectal cancer remains unclear. We aimed to establish a novel pyroptosis-associated model for the prognosis of colorectal cancer.

Methods

Pyroptosis-related genes were extracted using Gene Set Enrichment Analysis. A least absolute shrinkage and selection operator regression model was constructed to identify a pyroptosis-related gene signature using the Cancer Genome Atlas and Gene Expression Omnibus databases. Then, Kyoto Encyclopedia of Genes and Genomes and Gene Ontology and GSEA were performed to better understand the potential mechanisms and the functional pathways associated with pyroptosis involved in colorectal cancer. The relationship between the pyroptosis-related signature and immune infiltration was investigated using Cell-Type Identification by Estimating Relative Subsets of RNA Transcripts and MCPcounter.

Results

A 12 pyroptosis-related gene signature was identified. Then, patients were classified into high- and low-risk groups. Kaplan–Meier and receiver operating characteristic analyses confirmed that the high-risk groups showed worse overall survival, progression-free survival, or relapse-free survival probability. Functional enrichment analysis showed that pyroptosis was associated with extracellular matrix-related pathways. Furthermore, the pyroptosis risk score was associated with immune infiltration. The low-risk group exhibited a higher percentage of plasma cells, CD4 T cells, activated dendritic cells, and activated mast cells. M2 macrophages and M0 macrophages were positively related to the risk score.

Conclusion

Our research yielded a novel pyroptosis-related prognostic signature for colorectal cancer that was related to immune cell infiltration, and it provided an immunological perspective for developing personalized therapies.

Comprehensive analysis of expression profile and prognostic significance of interferon regulatory factors in pancreatic cancer

BACKGROUND

Pancreatic cancer (PC) is a highly lethal disease and an increasing cause of cancer-associated mortality worldwide. Interferon regulatory factors (IRFs) play vital roles in immune response and tumor cellular biological processes. However, the specific functions of IRFs in PC and tumor immune response are far from systematically clarified. This study aimed to explorer the expression profile, prognostic significance, and biological function of IRFs in PC.

RESULTS

We observed that the levels of IRF2, 6, 7, 8, and 9 were elevated in tumor compared to normal tissues in PC. IRF7 expression was significantly associated with patients' pathology stage in PC. PC patients with high IRF2, low IRF3, and high IRF6 levels had significantly poorer overall survival. High mRNA expression, amplification and, deep deletion were the three most common types of genetic alterations of IRFs in PC. Low expression of IRF2, 4, 5, and 8 was resistant to most of the drugs or small molecules from Genomics of Drug Sensitivity in Cancer. Moreover, IRFs were positively correlated with the abundance of tumor infiltrating immune cells in PC, including B cells, CD8+ T cells, CD4+ T cells, macrophages, Neutrophil, and Dendritic cells. Functional analysis indicated that IRFs were involved in T cell receptor signaling pathway, immune response, and Toll-like receptor signaling pathway.

CONCLUSIONS

Our results indicated that certain IRFs could serve as potential therapeutic targets and prognostic biomarkers for PC patients. Further basic and clinical studies are needed to validate our findings and generalize the clinical application of IRFs in PC.

IRF2-induced Claudin-7 suppresses cell proliferation, invasion and migration of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common type of malignant tumor worldwide. Claudin-7 (CLDN7) has been reported to exhibit low expression in tissues of patients with OSCC; however, the underlying mechanisms of CLDN7 remain to be elucidated. The present study aimed to investigate the effects of CLDN7 on the progression of OSCC and identify its potential regulatory mechanisms. CLDN7 and interferon regulatory factor-2 (IRF2) expression in several OSCC cell lines were detected using reverse transcription-quantitative PCR (RT-qPCR) and western blotting. Following CLDN7 overexpression, cell proliferation, invasion and migration were determined using a Cell Counting Kit-8, colony formation, Transwell and wound healing assays, respectively. The potential binding sites of IRF2 on the CLDN7 promoter were analyzed using the PROMO and JASPAR databases, which were verified via chromatin immunoprecipitation and RT-qPCR assays. The effects of IRF2 and CLDN7 on the biological functions of OSCC cells were examined by transfection with short hairpin RNA (shRNA) against CLDN7 (sh-CLDN7), or IRF2 and CLDN7 overexpression plasmids. The results revealed that CLDN7 and IRF2 expression were significantly downregulated in OSCC cell lines, and CLDN7 overexpression reduced the proliferation, invasion and migration of OSCC cells. Additionally, IRF2 was confirmed to combine with the CLDN7 promoter. CLDN7 silencing reversed the inhibitory effects of IRF2 overexpression on the proliferation, invasion and migration of OSCC cells. Taken together, these findings demonstrated that IRF2-induced CLDN7 upregulation suppressed the proliferation, invasion and migration of OSCC cells, suggesting the possibility of CLDN7 and IRF2 as novel targets for the treatment of OSCC.

The expression of the alpha1 subunit of Na+/K+-ATPase is related to tumor development and clinical outcomes in gastric cancer

BACKGROUND

The Na⁺/K⁺-ATPase alpha1 subunit (ATP1A1) is a critical component of Na⁺/K⁺-ATPase (NKA), a membrane pump that maintains a low intracellular Na⁺/K⁺ ratio and retains cellular volume and osmolarity. ATP1A1 was recently implicated in tumor behavior. Therefore, the present study investigated the role of ATP1A1 in patients with gastric cancer (GC).

METHODS

Knockdown experiments were conducted on human GC cell lines using ATP1A1 siRNA, and its effects on proliferation, the cell cycle, apoptosis, and cellular movement were examined. Gene expression profiling was performed by a microarray analysis. Primary tumor samples from 192 GC patients who underwent gastrectomy were subjected to an immunohistochemical analysis.

RESULTS

High ATP1A1 expression levels were observed in NUGC4 and MKN74 cells. Cell proliferation was suppressed and apoptosis was induced by the siRNA-induced knockdown of ATP1A1. The microarray analysis showed that knockdown of ATP1A1 leads to the up-regulated expression of genes involved in the interferon (IFN) signaling pathway, such as STAT1, STAT2, IRF1, and IRF9. Furthermore, the depletion of ATP1A1 altered the phosphorylation of the MAPK pathway. The immunohistochemical analysis revealed that the expression of ATP1A1 was associated with the histological type, venous invasion, and the pathological T stage. Furthermore, the prognostic analysis showed a relationship between high ATP1A1 expression levels and poor postoperative survival.

CONCLUSIONS

ATP1A1 appears to regulate tumor progression by altering IFN signaling, and high ATP1A1 expression levels were associated with poor postoperative survival in GC patients. The present results provide novel insights into the function of ATP1A1 as a mediator and/or biomarker of GC.

Interferon Regulatory Factor 2 (IRF2) Inhibits the Invasion and Migration of Renal Clear Cell Carcinoma Cells by Downregulation of Spindle Pole Body Component 24 (SPC24)

It has been reported that the increased expression of SPC24 (spindle pole body component 24) was involved in the initiation and development of various cancers. However, the role of SPC24 in ccRCC (clear cell renal cell carcinoma) remains largely unknown. In the present study, the changes and correlation of SPC24 and IRF2 (interferon regulatory factor 2) with ccRCC were evaluated by using GEPIA, TCGA and GTEx database. Then the involvement of SPC24 and IRF2 in invasion and migration was investigated in CaKi-1 cells, a human renal adenocarcinoma cell line. The bioinformatics assay revealed that the expression of SPC24 and IRF2 in kidney tissue of patients with renal clear cell cancer was significantly increased, and the expression of SPC24 and IRF2 in kidney tissue was positively and negatively related to cancer phase and survival rate in patients with ccRCC respectively. Notably, in vitro experimental study demonstrated that SPC25 promoted the invasion and migration of CaKi-1 cells, a human renal adenocarcinoma cell line. Furthermore, IRF2 shows potential binding site with SPC24 promoter, IRF2 overexpression significantly decreased SPC24 mRNA level, whereas inhibition of IRF2 with specific small hairpin RNA (shRNA) significantly increased SPC24 mRNA level. Functionally, inhibition of SPC24 with specific shRNA reversed the stimulatory effect of IRF2 shRNA on the invasion and migration of cells, whereas SPC24 over-expression reversed the inhibitory effect of IRF2 overexpression on the invasion and migration of cells. Finally, ChIP (chromatin immunoprecipitation) assay shows that IRF2 could directly bind with SPC24 promoter. In conclusion, these results demonstrated that IRF2/SPC24 signaling pathway contributes to the increased invasion and migration in ccRCC.

Grass carp (Ctenopharyngodon idella) interferon regulatory factor 8 down-regulates interferon1 expression via interaction with interferon regulatory factor 2 in vitro

Interferon regulatory factor 8 (IRF8), also known as interferon consensus sequence-binding protein (ICSBP), is a negative regulatory factor of interferon (IFN) and plays an important role in cell differentiation and innate immunity in mammals. In recent years, some irf8 homologous genes have been cloned and confirmed to take part in innate immune response in fish, but the mechanism still remains unclear. In this paper, a grass carp (Ctenopharyngodon idella) irf8 gene (Ciirf8) was cloned and characterized. The deduced protein (CiIRF8) possesses a highly conserved N-terminal DNA binding domain but a less well-conserved C-terminal IRF association domain (IAD). Ciirf8 was widely expressed in all tested tissues of grass carp and up-regulated following poly(I:C) stimulation. Ciirf8 expression was also up-regulated in CIK cells upon treatment with poly(I:C). To explore the molecular mechanism of how fish IRF8 regulates ifn1 expression, the similarities and differences of grass carp IRF8 and IRF2 were compared and contrasted. Subcellular localization analysis showed that CiIRF8 is located both in the cytoplasm and nucleus; however, CiIRF2 is only located in the nucleus. The nuclear-cytoplasmic translocation of CiIRF8 was observed in CIK cells under stimulation with poly(I:C). The interaction of CiIRF8 and CiIRF2 was further confirmed by a co-immunoprecipitation assay in the nucleus. Dual-luciferase reporter assays showed that the promoter activity of Ciifn1 was significantly inhibited by co-transfection with CiIRF2 and CiIRF8. The transcription inhibition of Ciifn1 was alleviated by competitive binding of CiIRF2 and CiIRF8 to CiIRF1. In conclusion, CiIRF8 down-regulates Ciifn1 expression via interaction with CiIRF2 in cells.

Identification of Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer

Purpose: The authors aimed to identify Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer. Methods: First, critical Notch signaling pathway genes were screened using The Cancer Genome Atlas and validation sets. Second, immune infiltration, protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis analyses were performed. Finally, potential immunotherapy drug targets were screened using T-cell receptors, B-cell receptors and CERES scores for bladder cancer. Results: The NOTCH7 gene was identified, with a significant difference in immune infiltration level between mutant and wild type in bladder cancer, mainly related to T cells. NOTCH7 was an immunotherapy prognostic factor, and IRF1 and B2M were the potential drug targets for NOTCH7 mutation in bladder cancer. Conclusion: NOTCH7 gene mutation can be used as an immunotherapy biomarker for bladder cancer.

IRF2 regulates cellular survival and Lenvatinib-sensitivity of hepatocellular carcinoma (HCC) through regulating β-catenin

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IRF2 and β-catenin are highly expressed in HCC tissues.

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IRF2 upregulation of β-catenin promotes HCC cell proliferation.

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IRF2 enhances lenvatinib resistance in HCC cells.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Lenvatinib oral chemotherapy is approved as a first-line treatment of patients with unresectable HCC. The efficacy and therapeutic duration of lenvatinib are limited by drug resistance, and the mechanism is unclear. IRF2 is a constitutive transcription factor associated with the development of various cancers by regulating cancer cell growth, apoptosis, and drug resistance. However, the potential role of IRF2 in lenvatinib resistance in HCC has not been explored. In this study, we found that IRF2 promoted proliferation, inhibited apoptosis, and increased lenvatinib resistance of HCC cells by regulating β-catenin expression. Silencing IRF2 downregulated the expression of β-catenin, while overexpressing IRF2 upregulated β-catenin. Moreover, the expression of β-catenin and IRF2 was positively correlated in HCC tissues. Inhibiting β-catenin with XAV-939 effectively abrogated β-catenin expression caused by lenvatinib treatment. These findings identify an important function of IRF2 in HCC and demonstrate a mechanism of lenvatinib resistance of HCC cells. Targeting IRF2 may be a potential strategy to improve the therapeutic effect of lenvatinib on HCC.

Oncolytic Virotherapy: The Cancer Cell Side

Simple Summary

Oncolytic viruses (OVs) are a promising immunotherapy that specifically target and kill cancer cells and stimulate anti-tumor immunity. While different OVs are endowed with distinct features, which enhance their specificity towards tumor cells; attributes of the cancer cell also critically contribute to this specificity. Such features comprise defects in innate immunity, including antiviral responses, and the metabolic reprogramming of the malignant cell. The tumorigenic features which support OV replication can be intrinsic to the transformation process (e.g., a direct consequence of the activity of a given oncogene), or acquired in the course of tumor immunoediting—the selection process applied by antitumor immunity. Oncogene-induced epigenetic silencing plays an important role in negative regulation of immunostimulatory antiviral responses in the cancer cells. Reversal of such silencing may also provide a strong immunostimulant in the form of viral mimicry by activation of endogenous retroelements. Here we review features of the cancer cell that support viral replication, tumor immunoediting and the connection between oncogenic signaling, DNA methylation and viral oncolysis. As such, this review concentrates on the malignant cell, while detailed description of different OVs can be found in the accompanied reviews of this issue.

Abstract

Cell autonomous immunity genes mediate the multiple stages of anti-viral defenses, including recognition of invading pathogens, inhibition of viral replication, reprogramming of cellular metabolism, programmed-cell-death, paracrine induction of antiviral state, and activation of immunostimulatory inflammation. In tumor development and/or immunotherapy settings, selective pressure applied by the immune system results in tumor immunoediting, a reduction in the immunostimulatory potential of the cancer cell. This editing process comprises the reduced expression and/or function of cell autonomous immunity genes, allowing for immune-evasion of the tumor while concomitantly attenuating anti-viral defenses. Combined with the oncogene-enhanced anabolic nature of cancer-cell metabolism, this attenuation of antiviral defenses contributes to viral replication and to the selectivity of oncolytic viruses (OVs) towards malignant cells. Here, we review the manners by which oncogene-mediated transformation and tumor immunoediting combine to alter the intracellular milieu of tumor cells, for the benefit of OV replication. We also explore the functional connection between oncogenic signaling and epigenetic silencing, and the way by which restriction of such silencing results in immune activation. Together, the picture that emerges is one in which OVs and epigenetic modifiers are part of a growing therapeutic toolbox that employs activation of anti-tumor immunity for cancer therapy.

TRIB3 promotes oral squamous cell carcinoma cell proliferation by activating the AKT signaling pathway

Tribbles pseudokinase 3 (TRIB3), a member of the tribbles-related family, has biological roles such as by acting as an oncogene or tumor suppressor gene, in various types of cancer, including colorectal cancer, breast cancer, lung cancer and renal cell carcinoma. However, the role of TRIB3 in oral squamous cell carcinoma (OSCC) is remains unclear. The current was aimed to determine the biological function of TRIB3 in OSCC progression. TRIB3 expression was examined in OSCC surgical specimens using reverse transcription-quantitative PCR and the role of TRIB3 in the proliferation capacities of OSCC cell lines was examined using crystal violet and MTT assays in vitro and tumorigenicity assays in vivo. The underlying mechanism by which TRIB3 exerts its function was investigated using western blotting. The results demonstrated that the mRNA and protein expression levels of TRIB3 were higher in human OSCC tissues compared with normal tissues. The role of TRIB3 in cell proliferation was also determined. TRIB3 overexpression significantly promoted OSCC cell proliferation, whereas TRIB3 knockdown inhibited OSCC cell proliferation compared with control cells. TRIB3 knockdown also suppressed tumor growth and decreased tumor volume in vivo compared with control cells. Moreover, the results suggested that TRIB3 overexpression increased the phosphorylation of protein kinase B (AKT) and mammalian target of rapamycin (mTOR), whereas TRIB3 knockdown decreased the phosphorylation of AKT and mTOR compared with control cells. To summarize, the present study indicated that TRIB3 promoted OSCC cell proliferation by activating the AKT signaling pathway; therefore, TRIB3 may serve as a potential target for the diagnosis and treatment of OSCC.

KDM6A suppresses hepatocellular carcinoma cell proliferation by negatively regulating the TGF-β/SMAD signaling pathway

Lysine demethylase 6A (KDM6A) is a Jumonji-C domain-containing histone demethylase that specifically catalyzes the removal of histone H3 lysine-27 trimethylation. KDM6A is a member of the KDM6 family, the biological role of which has been reported in various types of cancer, including bladder and lung cancer, as well as pancreatic ductal adenocarcinoma. However, the role of KDM6A in hepatocellular carcinoma (HCC) is not completely understood. Therefore, the present study aimed to determine the biological function of KDM6A in HCC progression. The expression profile of KDM6A was examined in HCC surgical specimens using reverse transcription-quantitative PCR. In addition, the role of KDM6A in the proliferation capacities of HCC cell lines was examined in vitro and in vivo using crystal violet and MTT assays. The underlying mechanism by which KDM6A exerts its function was explored by western blotting. The present study indicated that KDM6A was significantly downregulated in HCC tissues compared with normal control tissues. The role of KDM6A in HCC cell proliferation was also determined. KDM6A overexpression significantly inhibited HCC cell proliferation, whereas KDM6A knockdown significantly promoted HCC cell proliferation compared with the corresponding control groups. Consistently, KDM6A overexpression suppressed HCC cell tumorigenesis in vivo. The western blotting results indicated that KDM6A overexpression decreased the phosphorylation levels of smad2, whereas KDM6A knockdown increased the phosphorylation levels of smad2 compared with the corresponding control groups. Therefore, the present study suggested that KDM6A may inhibit HCC cell proliferation by negatively regulating the TGF-β/SMAD signaling pathway, suggesting that KDM6A may serve as a potential target for the diagnosis and treatment of HCC.

B Cell-Intrinsic Expression of Interferon Regulatory Factor 1 Supports Chronic Murine Gammaherpesvirus 68 Infection

Gammaherpesviruses are ubiquitous pathogens that are associated with cancers, including B cell lymphomas. These viruses are unique in that they infect naive B cells and subsequently drive a robust polyclonal germinal center response in order to amplify the latent reservoir and to establish lifelong infection in memory B cells. The gammaherpesvirus-driven germinal center response in combination with robust infection of germinal center B cells is thought to precipitate lymphomagenesis. Importantly, host and viral factors that selectively affect the gammaherpesvirus-driven germinal center response remain poorly understood. Global deficiency of antiviral tumor-suppressive interferon regulatory factor 1 (IRF-1) selectively promotes the murine gammaherpesvirus 68 (MHV68)-driven germinal center response and expansion of the viral latent reservoir. To determine the extent to which antiviral effects of IRF-1 are B cell intrinsic, we generated mice with conditional IRF-1 deficiency. Surprisingly, B cell-specific IRF-1 deficiency attenuated the establishment of chronic infection and the germinal center response, indicating that MHV68 may, in a B cell-intrinsic manner, usurp IRF-1 to promote the germinal center response and expansion of the latent reservoir. Further, we found that B cell-specific IRF-1 deficiency led to reduced levels of active tyrosine phosphatase SHP1, which plays a B cell-intrinsic proviral function during MHV68 infection. Finally, results of this study indicate that the antiviral functions of IRF-1 unveiled in MHV68-infected mice with global IRF-1 deficiency are mediated via IRF-1 expression by non-B cell populations.IMPORTANCE Gammaherpesviruses establish lifelong infection in over 95% of all adults and are associated with B cell lymphomas. The virus's manipulation of the germinal center response and B cell differentiation to establish lifelong infection is thought to also precipitate malignant transformation, through a mechanism that remains poorly understood. The host transcription factor IRF-1, a well-established tumor suppressor, selectively attenuates MHV68-driven germinal center response, a phenotype that we originally hypothesized to occur in a B cell-intrinsic manner. In contrast, in testing, B cell-intrinsic IRF-1 expression promoted the MHV68-driven germinal center response and the establishment of chronic infection. Our report highlights the underappreciated multifaceted role of IRF-1 in MHV68 infection and pathogenesis.

BUB1 promotes proliferation of liver cancer cells by activating SMAD2 phosphorylation

Budding uninhibited by benzimidazoles 1 (BUB1) is a mitotic checkpoint serine/threonine kinase that has been reported as an oncogene or tumor suppressor gene in various types of cancer, including breast cancer, pancreatic ductal adenocarcinoma, prostate and gastric cancers. However, its role in liver cancer remains unclear. The present study aimed to explore the biological function of BUB1 in liver cancer. The present study demonstrated that BUB1 mRNA expression levels and the intensity of immunohistochemical staining were significantly increased in liver cancer tissues compared with normal tissues. The role of BUB1 in cell proliferation was also determined. Overexpression of BUB1 significantly promoted cell proliferation, whereas knockdown of BUB1 expression inhibited the proliferation of liver cancer cell lines. In experiments investigating the underlying mechanism, overexpression of BUB1 increased the levels of SMAD2 phosphorylation, whereas knockdown of BUB1 reduced the levels of SMAD2 phosphorylation. Therefore, BUB1 may promote proliferation of liver cancer cells by activating phosphorylation of SMAD2, and BUB1 may serve as a potential target in the diagnosis and/or treatment of liver cancer.

IRF-2 Inhibits Gastric Cancer Invasion and Migration by Down-Regulating MMP-1

PURPOSE

The interferon regulatory factor 2 (IRF-2) acted as a tumor suppressor. We inspected IRF-2 as a predictor of prognosis in gastric cancer (GC) patients and tried to find out the potential molecular mechanism.

METHODS

In this study, the association between IRF-2 expression and clinical or prognosis significance was investigated in 86 pairs of tumor and the adjacent normal gastric tissues from GC patients. After establishing the stable cell lines, the Transwell assays were deduced to evaluate the malignancy of tumor. Then, microarray assay was carried out and the GO/KEGG pathway analyses were conducted to identify IRF-2's target gene. The relationship between IRF-2 and matrix metalloproteinases 1 (MMP-1) was also investigated by the immunohistochemistry in 15 pairs of tumor and adjacent normal gastric tissues.

RESULTS

We found that IRF-2 expression level in GC was significantly correlated with the prognosis of the patients. Transwell assays suggested an impaired ability of invasion and migration in IRF-2-overexpressed GC cells and a progressive malignant phenotype in IRF-2-knockdown GC cells. Ninety differentially expressed genes were found between IRF-2-overexpressed GC cells and its normal control sets by microarray. We demonstrated that MMP-1 was canonical in the network of differentially expressed genes by GO and KEGG pathway analysis and its expression level was markedly decreased in IRF-2-overexpressed cells of MKN-45 and increased in IRF-2-knockdown cells of SGC-7901. The expression of MMP-1 was inversely correlated with IRF-2 in GAC TMA specimens.

CONCLUSION

IRF-2 may inhibit GC progression by down-regulating MMP-1 level.

Genome-Wide Tiling Array Analysis of HPV-Induced Warts Reveals Aberrant Methylation of Protein-Coding and Non-Coding Regions

The human papillomaviruses (HPV) are a group of double-stranded DNA viruses that exhibit an exclusive tropism for squamous epithelia. HPV can either be low- or high-risk depending on its ability to cause benign lesions or cancer, respectively. Unsurprisingly, the majority of epigenetic research has focused on the high-risk HPV types, neglecting the low-risk types in the process. Therefore, the main objective of this study is to better understand the epigenetics of wart formation by investigating the differences in methylation between HPV-induced cutaneous warts and normal skin. A number of clear and very significant differences in methylation patterns were found between cutaneous warts and normal skin. Around 55% of the top-ranking 100 differentially methylated genes in warts were protein coding, including the EXOC4, KCNU, RTN1, LGI1, IRF2, and NRG1 genes. Additionally, non-coding RNA genes, such as the AZIN1-AS1, LINC02008, and MGC27382 genes, constituted 11% of the top-ranking 100 differentially methylated genes. Warts exhibited a unique pattern of methylation that is a possible explanation for their transient nature. Since the genetics of cutaneous wart formation are not completely known, the findings of the present study could contribute to a better understanding of how HPV infection modulates host methylation to give rise to warts in the skin.

Expression levels of EPHB4, EFNB2 and caspase-8 are associated with clinicopathological features and progression of esophageal squamous cell cancer

The upregulation of EPH receptor B4 (EPHB4) results in a survival advantage for tumor cells via the inhibition of the casapse-8-mediated apoptotic pathway, which begins from the cell membrane. The present study investigated the expression patterns of EPHB4, ephrin B2 (EFNB2) and caspase-8 in patients with esophageal squamous cell carcinoma (ESCC). The association between the expression patterns and certain clinicopathological characteristics of the patients was also determined. mRNA levels of EPHB4, EFNB2 and caspase-8 in paired primary ESCC samples and adjacent esophageal tissues collected from 96 patients with ESCC were quantified using quantitative PCR. Upregulation of EPHB4 and EFNB2 mRNA expression, and downregulation of caspase-8 mRNA were detected in ESCC samples compared with that in the adjacent esophageal tissues. The expression levels of EPHB4 and EFNB2 were positively correlated with each other, whereas the mRNA levels of both EPHB4 and EFNB2 exhibited a negative correlation with that of caspase-8. The mRNA levels of both EPHB4 and EFNB2 demonstrated a significant positive association with certain clinicopathological features of patients with ESCC, including family history, tumor size, metastasis and stage. Conversely, a negative association was revealed between the expression level of caspase-8 and clinicopathological features of patients with ESCC. Moreover, mRNA expression levels of EPHB4 and EFNB2 were negatively associated with survival times of patients with ESCC, whereas the level of caspase-8 was positively associated with patient outcome. The results from the present study suggested that EPHB4, EFNB2 and caspase-8 may be implicated in the tumorigenesis and progression of ESCC, and that consequently, they may serve as useful prognostic markers, as well as potential therapeutic targets.

Anti-apoptotic effect by the suppression of IRF1 as a downstream of Wnt/β-catenin signaling in colorectal cancer cells

Impaired Wnt signaling pathway plays a crucial role in the development of colorectal cancer through activation of the β-catenin/TCF7L2 complex. Although genes upregulated by Wnt/β-catenin signaling have been intensively studied, the roles of downregulated genes are poorly understood. Previously, we reported that interferon-induced proteins with tetratricopeptide repeats 2 (IFIT2) was downregulated by the Wnt/β-catenin signaling, and that the suppressed expression of IFIT2 conferred antiapoptotic property to colorectal cancer (CRC) cells. However, the mechanisms underlying how Wnt/β-catenin signaling regulates IFIT2 remain to be elucidated. In this study, we have uncovered that the expression of IFIT2 is induced by IRF1, which is negatively regulated by the Wnt/β-catenin signaling. In addition, we found that downregulation of IRF1 is mediated by its degradation through the ubiquitination-proteasome pathway, and that decreased activity of a deubiquitinase complex containing USP1 and UAF1 is involved in the degradation of IRF1 by Wnt/β-catenin signaling. These data should provide better understanding of the Wnt signaling pathway and human carcinogenesis.

Interferon-inducible lncRNA IRF1-AS represses esophageal squamous cell carcinoma by promoting interferon response

Interferons (IFNs) play crucial roles in the development and treatment of cancer. Long non-coding RNAs (lncRNAs) are emerging molecules involved in cancer progression. Here, we identified and characterized an IFN-inducible nuclear lncRNA IRF1-AS (Interferon Regulatory Factor 1 Antisense RNA) which was positively correlated with IRF1 expression. IFNs upregulate IRF1-AS via the JAK-STAT pathway. Knockdown and overexpression of IRF1-AS revealed that IRF1-AS inhibits oesophageal squamous cell carcinoma (ESCC) proliferation and promotes apoptosis in vitro and in vivo. Mechanistically, IRF1-AS activates IRF1 (Interferon Regulatory Factor 1) transcription through interacting with ILF3 (Interleukin Enhancer Binding Factor 3) and DHX9 (DExH-Box Helicase 9). In turn, IRF1 binds to the IRF1-AS promoter directly and activates IRF1-AS transcription. Global analysis of IRF1-AS-regulated genes indicated that IRF1-AS activates the IFN response in vitro and in vivo. IRF1 knockdown in IRF1-AS-overexpressing cells abolished the antiproliferative effect and activation of the IFN response. Furthermore, IRF1-AS was downregulated in ESCC tissues, and low expression correlated with poor prognosis. In conclusion, the interferon-inducible lncRNA IRF1-AS represses esophageal squamous cell carcinoma progression by promoting interferon response through a positive regulatory loop with IRF1.

Dysregulation of helper T lymphocytes in esophageal squamous cell carcinoma (ESCC) patients is highly associated with aberrant production of miR-21

Dysregulation of helper T (Th) cell subsets has been contributed to the initiation and propagation of esophageal squamous cell carcinoma (ESCC). Different microRNAs (miRNAs) have been reported to control the development and functions of tumor-associated immune cells in ESCC. Here, we aimed to assess the IL-10, TGF-β, IFN-γ, and IL-17a-producing CD3+CD8- T cells in association whit miR-21, miR-29b, miR-106a, and miR-155 expression in ESCC patients. A total of 34 ESCC patients including 12 newly diagnosed (ND) and 22 under-treatment (UT) cases and also 34 age-matched healthy donors were enrolled. Flow cytometric characterization of stimulated T cells was performed by staining of the cells with fluorescent conjugated specific anti-human CD3 and CD8 cell surface markers as well as IL-17a, IFN-γ, IL-10, and TGF-β intracytoplasmic cytokines. Circulating RNA was extracted from the plasma, and qRT-PCR was used to evaluate the expression of microRNAs. TGF-β plasma levels were also assessed by ELISA. Results showed that the frequency of Th cells was significantly reduced in patients. A significant increase in Treg as well as Th17 cells population in both patient subgroups was observed. ND patients showed elevated level of Th1 cells and IL-10. However the mean expression of IFN-γ was significantly decreased in Th cells. We also detected higher level of miR-21 in the ESCC patients which was significantly correlated with different subsets of Th cells. Our findings revealed that immune response related to the Th cells is highly impaired in ESCC patients. Association between miR-21 and Th subsets could be correlated with the impairment of anti-tumor immunity and ESCC pathogenesis, which could be potentially used as an important target for immunotherapeutic approaches.

MicroRNA-664 functions as an oncogene in cutaneous squamous cell carcinomas (cSCC) via suppressing interferon regulatory factor 2

BACKGROUND

Aberrant expression of microRNA-664 was involved in tumor growth and metastasis of various cancers. The specific role of miR-664 in cutaneous squamous cell carcinoma (cSCC) is yet to be elucidated.

OBJECTIVE

The present study aimed to investigate the molecular mechanisms underpinning of cSCC development and provide translational insights for future therapeutics.

METHODS

Human cSCC specimens were used to determine the miR-664 by in situhybridization and IRF2 by immunohistochemistry. To study the potential mechanisms in tumorigenesis, three cSCC cell lines including HSC-5, HSC-1 and A431 as well as BALB/C mouse tumor model was utilized.

RESULTS

We found that miR-664 was remarkably high in cSCC patient specimens and cSCC cell lines. Overexpression of miR-664 promotes tumorigenic behaviors such as increased cell proliferation, migration and invasion capacities in vitro and enhanced tumorigenicity in xenograft mouse model. Our data further identified IRF2 as a direct downstream target of miR-664. Knockdown of IRF2 reverses pro-tumorigenesis phenotype of miR-664; whereas IRF2 over-expression inhibits miR-664 tumorigenesis in cSCC. Together, it revealed miR-664 functions as an oncogene in cSCC via suppression of IRF2.

CONCLUSION

Our data demonstrates that aberrant expression of miR-664 plays a critical role in carcinogenesis of cSCC. The discovery of novel targets such as miR-664 and IRF2 will facilitate future development of therapeutic interventions.

Tumor suppressor Interferon Regulatory Factor 1 selectively blocks expression of endogenous retrovirus

Endogenous retroviruses (ERVs) comprise 10% of the genome, with many of these transcriptionally silenced post early embryogenesis. Several stimuli, including exogenous virus infection and cellular transformation can reactivate ERV expression via a poorly understood mechanism. We identified Interferon Regulatory Factor 1 (IRF-1), a tumor suppressor and an antiviral host factor, as a suppressor of ERV expression. IRF-1 decreased expression of a specific mouse ERV in vitro and in vivo. IRF-3, but not IRF-7, also decreased expression of distinct ERV families, suggesting that suppression of ERVs is a relevant biological function of the IRF family. Given the emerging appreciation of the physiological relevance of ERV expression in cancer, IRF-1-mediated suppression of specific ERVs may contribute to the overall tumor suppressor activity of this host factor.

Long non-coding RNA GAS5 is induced by interferons and plays an antitumor role in esophageal squamous cell carcinoma

The long non-coding RNA GAS5 has been reported as a tumor suppressor in many cancers. However, its functions and mechanisms remain largely unknown in esophageal squamous cell carcinoma (ESCC). In this study, we found that GAS5 was over-expressed in ESCC tissue compared with that in normal esophageal tissue in a public database. Functional studies showed that GAS5 could inhibit ESCC cell proliferation, migration and invasion in vitro. Further analysis revealed that GAS5 was regulated by interferon (IFN) responses via the JAK-STAT pathway. Moreover, as an IFN-stimulated gene (ISG), GAS5 was a positive regulator of IFN responses. The feedback loop between GAS5 and the IFN signaling pathway plays an important antitumor role in ESCC, thus providing novel potential therapeutic targets.

Interferon regulatory factor 1 inactivation in human cancer

Interferon regulatory factors (IRFs) are a group of closely related proteins collectively referred to as the IRF family. Members of this family were originally recognized for their roles in inflammatory responses; however, recent research has suggested that they are also involved in tumor biology. This review focusses on current knowledge of the roles of IRF-1 and IRF-2 in human cancer, with particular attention paid to the impact of IRF-1 inactivation. The different mechanisms underlying IRF-1 inactivation and their implications for human cancers and the potential importance of IRF-1 in immunotherapy are also summarized.

FABP4 suppresses proliferation and invasion of hepatocellular carcinoma cells and predicts a poor prognosis for hepatocellular carcinoma

Adipocyte fatty acid-binding protein (FABP4) is abundant in macrophage and adipocyte. It is known to be involved in lipid metabolism. The role of FABP4 has been reported in various cancers, such as non-small cell lung cancer, breast cancer, ovarian cancer, and prostatic cancer. However, its role remains unclear in hepatocellular carcinoma (HCC). In our study, we investigated the expression of FABP4 at both mRNA and protein levels, and by examining 175 cases of patients with cancer of the liver tissue microarray, the significance between the expression of FABP4 and clinical characteristics had been discussed. We found that FABP4 was lowly expressed in HCC tissues compared to the corresponding tissue adjacent, and the expression of FABP4 was significantly associated with the tumor size, PVTT, recurrence-free survival and overall survival. Moreover, multivariate Cox regression analysis indicated that the expression of FABP4, Alb, AFP, HBsAg, and PVTT were independent risk factors for overall survival, and the expression of FABP4, AFP, GGT, tumor size, and encapsulation were independent risk factors for HCC recurrence. In addition, we revealed that FABP4 suppressed HCC cell proliferation and invasion in vitro. Moreover, overexpression of FABP4 led to inhibit tumor growth and decreased tumor volume in vivo. These phenotypes were associated with altered expression of Snail and p-STAT3. Our studies thus suggest that FABP4 could be a potential target for HCC chemotherapy.

miR-302b inhibits cancer-related inflammation by targeting ERBB4, IRF2 and CXCR4 in esophageal cancer

Cancer related inflammation (CRI) plays an important role in the development of esophageal cancer (EC), and the target gene analysis shows that miR-302b potential target genes closely correlated to CRI important signaling pathways. The present study was to evaluate the inhibition of miR-302b on CRI in EC and its mechanism. We found that the expression levels of miR-302b in EC cells were lower than that in Het-1A cells, while TE11 with the lowest expression and OE33 with the highest. Inflammatory stimuli at 48 h significantly reduced expression of miR-302b in EC cells, but had no effect in Het-1A. After up-regulation of miR-302b in TE11 and down-regulation of miR-302b in OE33, it was found that miR-302b reduced CRI key transcription factors and representative cytokines. Then, over-expressed of miR-302b significantly altered potential target genes protein expressions and there was a negative correlation between miR-302b and potential target genes protein expressions (ERBB4, IRF2 and CXCR4) in EC tissues. Then reporter gene analysis revealed that miR-302b post-transcriptionally regulated expression of target genes by specific area of 3′-UTR. Transfected by target genes shRNA plasmids together could get the same effects of miR-302b on protein expression of CRI key transcription factors. Furthermore, miR-302b was able to repress tumor growth and transcription factors protein expression in vivo. These finding suggests that miR-302b inhibits key transcription factors and cytokines by targeting ERBB4, IRF2 and CXCR4, implicating its role in the inhibition of CRI in EC.

Prognostic value of IRF-2 expression in colorectal cancer

Interferon regulatory factor 2 (IRF-2) is known to play a pivotal role in the development and progression of several malignancies. As a crucial member of interferon regulatory factor family, the association between the expression of IRF-2 and clinical prognostic significance has not been fully explored in colorectal cancer (CRC). The purpose of our study was to investigate the expression profile of IRF-2 in CRC and to examine its association with clinical features. The expression levels of IRF-2 in 18 paired CRC and non-cancerous colorectal tissues were measured by quantitative real-time PCR (qRT-PCR) and those in 4 paired samples by Western blotting. The results showed a significant increase in IRF-2 mRNA expression and protein expression in CRC tissues compared to those in paired normal tissues. Besides, high expression of IRF-2 was significantly associated with distant metastasis (P = 0.041) and preoperative serum CEA level (P = 0.045). Kaplan-Meier survival analysis showed that patients with high expression of IRF-2 had a significantly worse overall survival than those with low expression of IRF-2 (P = 0.006). Further multivariate analysis indicated that IRF-2 and TNM stage were independent prognostic factors for overall survival in patients with CRC. Our study primarily suggests IRF-2 as a potential prognostic biomarker in CRC.

IRF-2 haploinsufficiency causes enhanced imiquimod-induced psoriasis-like skin inflammation

BACKGROUNDS

IFN regulatory factor (IRF)-2 is one of the potential susceptibility genes for psoriasis, but how this gene influences psoriasis pathogenesis is unclear. Topical application of imiquimod (IMQ), a TLR7 ligand, induces psoriasis-like skin lesions in mice.

OBJECTIVE

The aim of this study was to investigate whether IRF-2 gene status would influence severity of skin disease in IMQ-treated mice.

METHODS

Imiquimod-induced psoriasis-like skin inflammation was assessed by clinical findings, histology, and cytokine expression. The effects of imiquimod or IFN on peritoneal macrophages were analyzed in vitro.

RESULTS

IMQ-induced skin inflammation assessed by clinical findings and histology was more severe in IRF-2^+/- mice than in wild-type mice. In inflamed skin, mRNA expression levels of tumor necrosis factor (TNF)-α, IL-12/23p40, IL-17A, and IL-22 were significantly elevated in IRF-2^+/- mice compared to wild-type mice. Stimulation of peritoneal macrophages by IMQ significantly increased mRNA levels of TNF-α, IL-12/23p40, IL-23p19, IL-12p35, and IL-36. Interestingly, macrophages from IRF-2^+/- mice expressed higher levels of TNF-α, IL-12/23p40, and IL-36 compared to those from wild-type mice 24 h after stimulation, while they expressed similar levels of IL-12p35 and IL-23p19. Moreover, elevated mRNA expression of inducible nitric oxide synthase was observed only in IMQ-stimulated macrophages derived from IRF-2^+/- mice, which correlated with angiogenesis in IMQ-treated ears of IRF-2^+/- mice.

CONCLUSIONS

These results suggest that IRF-2 haploinsufficiency creates heightened biologic responses to IFN-α that phenotypically lead to enhanced angiogenesis and psoriasis-like inflammation within skin.

A 17-molecule set as a predictor of complete response to neoadjuvant chemotherapy with docetaxel, cisplatin, and 5-fluorouracil in esophageal cancer

Background

Recently, neoadjuvant chemotherapy with docetaxel/cisplatin/5-fluorouracil (NAC-DCF) was identified as a novel strong regimen with a high rate of pathological complete response (pCR) in advanced esophageal cancer in Japan. Predicting pCR will contribute to the therapeutic strategy and the prevention of surgical invasion. However, a predictor of pCR after NAC-DCF has not yet been developed. The aim of this study was to identify a novel predictor of pCR in locally advanced esophageal cancer treated with NAC-DCF.

Patients and methods

A total of 32 patients who received NAC-DCF followed by esophagectomy between June 2013 and March 2016 were enrolled in this study. We divided the patients into the following 2 groups: pCR group (9 cases) and non-pCR group (23 cases), and compared gene expressions between these groups using DNA microarray data and KeyMolnet. Subsequently, a validation study of candidate molecular expression was performed in 7 additional cases.

Results

Seventeen molecules, including transcription factor E2F, T-cell-specific transcription factor, Src (known as “proto-oncogene tyrosine-protein kinase of sarcoma”), interferon regulatory factor 1, thymidylate synthase, cyclin B, cyclin-dependent kinase (CDK) 4, CDK, caspase-1, vitamin D receptor, histone deacetylase, MAPK/ERK kinase, bcl-2-associated X protein, runt-related transcription factor 1, PR domain zinc finger protein 1, platelet-derived growth factor receptor, and interleukin 1, were identified as candidate molecules. The molecules were mainly associated with pathways, such as transcriptional regulation by SMAD, RB/E2F, and STAT. The validation study indicated that 12 of the 17 molecules (71%) matched the trends of molecular expression.

Conclusions

A 17-molecule set that predicts pCR after NAC-DCF for locally advanced esophageal cancer was identified.

Hyperactive mTOR induces neuroendocrine differentiation in prostate cancer cell with concurrent up-regulation of IRF1

BACKGROUND

Neuroendocrine-differentiated prostate cancer (NEPCa) is refractory to androgen deprivation therapy and shows a poor prognosis. The underlying mechanisms responsible for neuroendocrine differentiation (NED) are yet to be clarified. In this study, we investigated the role of mammalian target of rapamycin (mTOR) in NEPCa.

METHODS

We utilized a gain-of-function analysis by establishing a human PCa LNCaP stable line that expresses hyperactive mTOR (LNCaP-mTOR). Then, we employed a comprehensive mass spectrometric analysis to identify a key transcription factor in LNCaP-mTOR, followed by a loss-of-function analysis using CRISPR/Cas system.

RESULTS

The activation of mTOR induced NED. We observed significant cell growth arrest in NED of LNCaP-mTOR, which accompanied increased expression of p21^WAF1/CIP1 . A comprehensive mass spectrometric analysis identified interferon regulatory factor 1 (IRF1) as a key transcription factor in growth arrest of LNCaP-mTOR. The disruption of IRF1 gene in LNCaP-mTOR reversed cell growth arrest along with the suppression of its target p21^WAF1/CIP1 . These results indicate that the growth arrest in NED is at least in part dependent on IRF1 through the induction of p21^WAF1/CIP1 .

CONCLUSIONS

We identified active mTOR as a novel inducer of NED, and elucidated a mechanism underlying the malignant transformation of NEPCa by recapitulating NED in vitro.

Nasopharyngeal carcinoma super-enhancer-driven ETV6 correlates with prognosis

Nasopharyngeal carcinoma (NPC) most frequently occurs in southern China and southeast Asia. Epidemiology studies link NPC to genetic predisposition, Epstein-Barr virus (EBV) infection, and environmental factors. Genetic studies indicate that mutations in chromatin-modifying enzymes are the most frequent genetic alterations in NPC. Here, we used H3K27ac chromatin immune precipitation followed by deep sequencing (ChIP-seq) to define the NPC epigenome in primary NPC biopsies, NPC xenografts, and an NPC cell line, and compared them to immortalized normal nasopharyngeal or oral epithelial cells. We identified NPC-specific enhancers and found these enhancers were enriched with nuclear factor κB (NF-κB), IFN-responsive factor 1 (IRF1) and IRF2, and ETS family members ETS1 motifs. Normal cell-specific enhancers were enriched with basic leucine zipper family members and TP53 motifs. NPC super-enhancers with extraordinarily broad and high H3K27ac signals were also identified, and they were linked to genes important for oncogenesis including ETV6. ETV6 was also highly expressed in NPC biopsies by immunohistochemistry. High ETV6 expression correlated with a poor prognosis. Furthermore, we defined the EBV episome epigenetic landscapes in primary NPC tissue.

MicroRNA-18a-5p functions as an oncogene by directly targeting IRF2 in lung cancer

Lung cancer is the major form of cancer resulting in cancer-related mortality around the world. MicroRNAs are endogenous small non-coding single-stranded RNAs, which can engage in the regulation of gene expression. In this study, miR-18a-5p significantly upregulated in non-small cell lung cancer (NSCLC) tissues and NSCLC cell lines, suggesting an oncogenic function in lung cancer. Additionally, miR-18a-5p can promote carcinogenesis by directly targeting interferon regulatory factor 2 (IRF2). Further experiments indicated that IRF2 can increase cell apoptosis, inhibit cell proliferation and migration ability. Our study demonstrates that miR-18a-5p promotes autophagy in NSCLC. Collectively, these results indicate that miR-18a-5p can not only promote NSCLC by suppressing IRF2, but also will be a promising target in the near future.

MicroRNA-520c enhances cell proliferation, migration, and invasion by suppressing IRF2 in gastric cancer

Dysregulation of microRNA (miRNA) is actively involved in the development and progression of gastric cancer (GC). MiR‐520c was previously found to be overexpressed in GC specimens and cells. However, the clinical significance of miR‐520c and its biological function in GC remain largely unknown. Here, we found that miR‐520c expression in GC tissues was significantly increased compared to normal adjacent gastric tissues. Its increased level was prominently correlated with poor clinical parameters and prognosis of GC patients. Accordingly, the expression of miR‐520c was obviously elevated in GC cell lines as compared with gastric epithelial cells. Overexpression of miR‐520c in N‐87 cells significantly increased the proliferative ability, migration, and invasion of cancer cells, while miR‐520c silencing suppressed MKN‐45 cell proliferation, migration, and invasion in vitro. Mechanically, miR‐520c inversely regulated interferon regulatory factor 2 (IRF2) abundance in GC cells. Herein, IRF2 was found to be a downstream target of miR‐520c in GC. Furthermore, IRF2 was down‐regulated in GC tissues compared to nontumor tissues. An inverse correlation between IRF2 and miR‐520c expression was observed in GC cases. Taken together, miR‐520c may serve as a prognostic predictor and a therapeutic target for GC patients.

Upregulation of microRNA-450 inhibits the progression of lung cancer in vitro and in vivo by targeting interferon regulatory factor 2

MicroRNAs (miRNAs) are a class of non‑coding RNAs that play pivotal roles in human lung cancer development. The majority of studies have focused on either non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC). In the present study, we investigated a plausible mechanism of action of miR‑450 in these types of lung cancer. We found that the level of miR‑450 was decreased in lung cancer cell lines, as well as in solid tumors. As exemplified in the H510A (SCLC) and H2291 (NSCLC) cells, transfection with lentivirus carrying miR‑450 upregulated miR‑450 expression and significantly attenuated lung cancer cell proliferation and invasion, as well as the growth of implantated tumors. Interferon regulatory factor 2 (IRF2) was also verified to be a direct target of miR‑450 in lung cancer cells. The overexpression of IRF2 in the H510A and H2291 cells abrogated the inhibitory effects of miR‑450 on lung cancer cell proliferation and invasion. Taken together, in this study, we identified a novel role of miR‑450 in lung cancer. miR-450 targets IRF2 and thus supresses lung cancer cell proliferation and invasion.

Innate Immune Responses in ALV-J Infected Chicks and Chickens with Hemangioma In Vivo

Avian leukosis virus subgroup J (ALV-J) infection can cause tumors and immunosuppression. Since the precise mechanism of the innate immune response induced by ALV-J is unknown, we investigated the antiviral innate immune responses induced by ALV-J in chicks and chickens that had developed tumors. Spleen levels of interleukin-6 (IL-6), IL-10, IL-1β, and interferon-β (IFN-β) were not significantly different between the infected chick groups and the control groups from 1 day post hatch to 7 days post hatch. However, IL-6, IL-1β, and IFN-β protein levels in the three clinical samples with hemangiomas were dramatically increased compared to the healthy samples. In addition, the anti-inflammatory cytokine IL-10 increased sharply in two of three clinical samples. We also found a more than 20-fold up-regulation of ISG12-1 mRNA at 1 day post infection (d.p.i.) and a twofold up-regulation of ZC3HAV1 mRNA at 4 d.p.i. However, there were no statistical differences in ISG12-1 and ZC3HAV1 mRNA expression levels in the tumorigenesis phase. ALV-J infection induced a significant increase of Toll-like receptor 7 (TLR-7) at 1 d.p.i. and dramatically increased the mRNA levels of melanoma differentiation-associated gene 5 (MDA5) in the tumorigenesis phase. Moreover, the protein levels of interferon regulatory factor 1 (IRF-1) and signal transducer and activator of transcription 1 (STAT1) were decreased in chickens with tumors. These results suggest that ALV-J was primarily recognized by chicken TLR7 and MDA5 at early and late in vivo infection stages, respectively. ALV-J strain SCAU-HN06 did not induce any significant antiviral innate immune response in 1 week old chicks. However, interferon-stimulated genes were not induced normally during the late phase of ALV-J infection due to a reduction of IRF1 and STAT1 expression.

MicroRNA-18a modulates P53 expression by targeting IRF2 in gastric cancer patients

BACKGROUND AND AIM

MicroRNA-18a (miR-18a) has been reported to be upregulated in gastric cancer (GC) tissues compared with normal gastric tissues. However, little is known about its prognostic value and biological roles.

METHODS

In this study, miR-18a expression in gastric adenocarcinoma (GAC) tissues and adjacent non-tumor tissues was validated by in situ hybridization, and the predictive values of miR-18a were explored. The biological roles of miR-18a and the underlying signal pathway were investigated in GC cell lines.

RESULTS

Overexpressed intra-tumoral miR-18a was associated with poor survival rate and was an independent prognostic factor for overall survival rate (P < 0.001) in GC patients. Forced expression of miR-18a remarkably enhanced cell proliferation, migration, and invasion in GC cells, while inhibition of miR-18a caused the opposite effects. Further study showed that miR-18a suppressed the expression of interferon regulatory factor 2 (IRF2) by directly binding to its 3'-untranslated region. Moreover, miR-18a expression levels are inversely correlated with IRF2 in human GC tissues. Western blot showed that forced expression of miR-18a could not only downregulate the expression of IRF2, but also inhibit the expression of P53, suggesting that IRF2 might play as a tumor suppressor by regulating P53 signaling in GC.

CONCLUSION

miR-18a modulated P53 expression by directly targeting IRF2 and had a high predictive value for prognosis of GAC patients. These results may lead to identification of therapeutic candidates of GC.

Tumor Suppressor Interferon-Regulatory Factor 1 Counteracts the Germinal Center Reaction Driven by a Cancer-Associated Gammaherpesvirus

Gammaherpesviruses are ubiquitous pathogens that are associated with the development of B cell lymphomas. Gammaherpesviruses employ multiple mechanisms to transiently stimulate a broad, polyclonal germinal center reaction, an inherently mutagenic stage of B cell differentiation that is thought to be the primary target of malignant transformation in virus-driven lymphomagenesis. We found that this gammaherpesvirus-driven germinal center expansion was exaggerated and lost its transient nature in the absence of interferon-regulatory factor 1 (IRF-1), a transcription factor with antiviral and tumor suppressor functions. Uncontrolled and persistent expansion of germinal center B cells led to pathological changes in the spleens of chronically infected IRF-1-deficient animals. Additionally, we found decreased IRF-1 expression in cases of human posttransplant lymphoproliferative disorder, a malignant condition associated with gammaherpesvirus infection. The results of our study define an unappreciated role for IRF-1 in B cell biology and provide insight into the potential mechanism of gammaherpesvirus-driven lymphomagenesis.

IMPORTANCE

Gammaherpesviruses establish lifelong infection in most adults and are associated with B cell lymphomas. While the infection is asymptomatic in many hosts, it is critical to identify individuals who may be at an increased risk of virus-induced cancer. Such identification is currently impossible, as the host risk factors that predispose individuals toward viral lymphomagenesis are poorly understood. The current study identifies interferon-regulatory factor 1 (IRF-1) to be one of such candidate host factors. Specifically, we found that IRF-1 enforces long-term suppression of an inherently mutagenic stage of B cell differentiation that gammaherpesviruses are thought to target for transformation. Correspondingly, in the absence of IRF-1, chronic gammaherpesvirus infection induced pathological changes in the spleens of infected animals. Further, we found decreased IRF-1 expression in human gammaherpesvirus-induced B cell malignancies.

IFNg-induced Irgm1 promotes tumorigenesis of melanoma via dual regulation of apoptosis and Bif-1-dependent autophagy

Interferon gamma (IFNg) has been known as the regulator for both tumor immune surveillance and tumorgenesis. However, mechanisms underlying the resistance of tumor cell to IFNg have yet been fully understood. In the current study, we showed that immunity-related GTPase family member 1 (mouse: Irgm1; human: IRGM) is essential for IFNg-mediated regulation of tumor cell growth in melanoma. IRGM/Irgm1 was highly expressed in human and mouse melanoma. IFNg and starvation synergistically induced Irgm1 expression in melanoma B16 cells. In vivo, injection of Irgm1-siRNA-treated cells significantly reduced the number of tumor nodules and prolonged the mice survival. In vitro, knockdown endogenous or IFNg-induced Irgm1 significantly decreases the proliferation and increases apoptosis of B16 cells. In addition, suppressing Irgm1 decreased the IFNg/starvation-induced autophagy, while overexpressing Irgm1 significantly increased autophagy and rescued starvation-challenged cells. Moreover, IFNg and starvation-induced the co-localization of Irgm1 with Bax-interacting factor 1 (Bif-1). Knockdown of Bif-1 decreased Irgm1-mediated tumor cell autophagy. Taken together, these data reveal an Irgm1-dependent mechanism that promotes the tumorigenesis of melanoma via dual regulation of apoptosis and Bif-1-dependent autophagy.

Altered gene expression patterns during the initiation and promotion stages of neonatally diethylstilbestrol-induced hyperplasia/dysplasia/neoplasia in the hamster uterus

Neonatal treatment of hamsters with diethylstilbestrol (DES) induces uterine hyperplasia/dysplasia/neoplasia (endometrial adenocarcinoma) in adult animals. We subsequently determined that the neonatal DES exposure event directly and permanently disrupts the developing hamster uterus (initiation stage) so that it responds abnormally when it is stimulated with estrogen in adulthood (promotion stage). To identify candidate molecular elements involved in progression of the disruption/neoplastic process, we performed: (1) immunoblot analyses and (2) microarray profiling (Affymetrix Gene Chip System) on sets of uterine protein and RNA extracts, respectively, and (3) immunohistochemical analysis on uterine sections; all from both initiation stage and promotion stage groups of animals. Here we report that: (1) progression of the neonatal DES-induced hyperplasia/dysplasia/neoplasia phenomenon in the hamster uterus involves a wide spectrum of specific gene expression alterations and (2) the gene products involved and their manner of altered expression differ dramatically during the initiation vs. promotion stages of the phenomenon.

Involvement of chromosome region maintenance 1 (CRM1) in the formation and progression of esophageal squamous cell carcinoma

Chromosome region maintenance 1 (CRM1) has been related to several malignancies. The predictive value of CRM1 in the malignance and prognosis of esophageal squamous cell carcinoma (ESCC), however, is not clear yet. In this study, we displayed that CRM1 expression was up-regulated in ESCC using immunohistochemistry and Western blot. Statistical analysis demonstrated that patients with high CRM1 levels indicated shorter survival period. We further found that silencing CRM1 caused apoptosis in ESCC cell lines. Moreover, knockdown of CRM1 disturbed the expression of tumor suppressor proteins and inhibited NF-κB activity in ESCC cell lines, especially if the cell line was treated with 5-fluorouracil. In consequence, our results for the first time indicated that CRM1 was dysregulated in ESCC, and suppression of CRM1 expression which resulted in inhibiting of NF-κB signaling might be developed into a new strategy in ESCC therapy.

The roles of interferon regulatory factors 1 and 2 in the progression of human pancreatic cancer

OBJECTIVE

Pancreatic cancer is one of the most malignant diseases worldwide. Interferon regulatory factor (IRF) 1 and IRF2 function as a tumor suppressor and oncoprotein, respectively, in several types of cancers. We investigated whether IRF1 and IRF2 are involved in the progression of pancreatic cancer.

METHODS

We examined the expressions of IRF1 and IRF2 in pancreatic cancer specimens and analyzed the association with clinicopathologic features. We evaluated the biological effects of IRF1 and IRF2 using a pancreatic cancer cell line.

RESULTS

The expression levels of IRF1 and IRF2 were decreased and increased, respectively, in the pancreatic cancer cells compared with those observed in the paired normal areas. A higher expression of IRF1 was associated with better features of tumor differentiation, infiltration depth, tumor size, and survival, whereas that of IRF2 was associated with a worse feature of tumor infiltration depth. Interferon regulatory factor 2-overexpressing PANC-1 cells exhibited an increase in cell growth, less apoptotic features, and chemoresistance to gemcitabine treatment. In contrast, IRF1-overexpressing cells exhibited the opposite characteristics.

CONCLUSIONS

Interferon regulatory factors 1 and 2 may regulate the progression of pancreatic cancer by functioning as an antioncoprotein and oncoprotein, respectively. These molecules may serve as potential targets of therapy.