IRF5 promotes the proliferation of human thyroid cancer cells

IRF5 suppresses metastasis through the regulation of tumor-derived extracellular vesicles and pre-metastatic niche formation

Metastasis is driven by extensive cooperation between a tumor and its microenvironment, resulting in the adaptation of molecular mechanisms that evade the immune system and enable pre-metastatic niche (PMN) formation. Little is known of the tumor-intrinsic factors that regulate these mechanisms. Here we show that expression of the transcription factor interferon regulatory factor 5 (IRF5) in osteosarcoma (OS) and breast carcinoma (BC) clinically correlates with prolonged survival and decreased secretion of tumor-derived extracellular vesicles (t-dEVs). Conversely, loss of intra-tumoral IRF5 establishes a PMN that supports metastasis. Mechanistically, IRF5-positive tumor cells retain IRF5 transcripts within t-dEVs that contribute to altered composition, secretion, and trafficking of t-dEVs to sites of metastasis. Upon whole-body pre-conditioning with t-dEVs from IRF5-high or -low OS and BC cells, we found increased lung metastatic colonization that replicated findings from orthotopically implanted cancer cells. Collectively, our findings uncover a new role for IRF5 in cancer metastasis through its regulation of t-dEV programming of the PMN.

Multi-ancestry genome-wide association study of kidney cancer identifies 63 susceptibility regions

Here, in a multi-ancestry genome-wide association study meta-analysis of kidney cancer (29,020 cases and 835,670 controls), we identified 63 susceptibility regions (50 novel) containing 108 independent risk loci. In analyses stratified by subtype, 52 regions (78 loci) were associated with clear cell renal cell carcinoma (RCC) and 6 regions (7 loci) with papillary RCC. Notably, we report a variant common in African ancestry individuals ( rs7629500 ) in the 3' untranslated region of VHL, nearly tripling clear cell RCC risk (odds ratio 2.72, 95% confidence interval 2.23-3.30). In cis-expression quantitative trait locus analyses, 48 variants from 34 regions point toward 83 candidate genes. Enrichment of hypoxia-inducible factor-binding sites underscores the importance of hypoxia-related mechanisms in kidney cancer. Our results advance understanding of the genetic architecture of kidney cancer, provide clues for functional investigation and enable generation of a validated polygenic risk score with an estimated area under the curve of 0.65 (0.74 including risk factors) among European ancestry individuals.

Cytoplasmic localization of IRF5 induces Wnt5a/E-cadherin degradation and promotes gastric cancer cells metastasis

IRF5, a nucleoplasm shuttling protein, is a pivotal transcription factor regulating immune system activity. It's well known that immunosuppression is involved in the development of gastric cancer. However, no data exist for the expression and function of IRF5 in gastric cancer. This study demonstrated that IRF5 was cytoplasm-enriched in gastric cancer cells. IRF5 promoted gastric cancer cell migration, which involved the inhibition of Wnt5a and E-cadherin proteins expression. IRF5 (LA) localized in nucleus had no significant effect on Wnt5a and E-cadherin expressions, while mutation of IRF5 (ΔNLS), which prevents IRF5 nuclear translocation, had more impact on these inhibitory effects. In addition, degradation rates of both Wnt5a and E-cadherin were enhanced by resiquimod, an IRF5 agonist. Further in vivo experiments indicated that IRF5 knockout of gastric cancer cells repressed their pulmonary metastasis in nude mice. Finally, the expression and clinical significance of IRF5 were analyzed using gastric cancer tissue microarrays, which suggested that the expression of IRF5 varied procedurally in different progressive stages of gastric cancer. Our data revealed that IRF5 cytoplasmic localization were associated with Wnt5a and E-cadherin degradation and gastric cancer cell metastasis. Inhibiting IRF5 expression and/or its cytoplasmic localization may provide a novel target for gastric cancer therapy.

Interferon regulatory factor 5‑induced upregulation of zinc‑finger protein 217 promotes pancreatic carcinoma progression

The aim of the present study was to investigate the molecular mechanisms of zinc‑finger protein 217 (ZNF217) in pancreatic carcinoma (PC) progression. ZNF217‑associated expression and survival data from patients with PC were retrieved from the Gene Expression Profiling Interactive Analysis server. The mRNA expression level of ZNF217 was detected by reverse transcription‑quantitative PCR. Cell Counting Kit‑8, colony formation, wound‑healing and Transwell assays were conducted to assess cellular proliferation, migratory and invasive abilities. Proliferation was also examined by immunofluorescence detection of Ki67 expression, and chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to detect the interaction between ZNF217 and interferon regulatory factor 5 (IRF5). ZNF217 was found to be significantly upregulated in tumor tissues and cancer cell lines, which was associated with a poor survival rate in patients with PC. ZNF217 silencing markedly suppressed cellular proliferation and migratory and invasive abilities, as well as decreased the expression of Ki67. IRF5 was also upregulated in PC tumor tissues and was shown to positively regulate the activity of the ZNF217 promoter and its mRNA expression levels. Furthermore, ChIP assays demonstrated that IRF5 bound to the promoter region of ZNF217 in vitro. In conclusion, ZNF217 silencing exerted notable inhibitory effects on the progression of PC. Thus, ZNF217 may serve as a potential target for developing novel therapeutic strategies for PC.

Overexpression of IRF3 Predicts Poor Prognosis in Clear Cell Renal Cell Carcinoma

Background

Growing findings have demonstrated that interferon regulatory transcription factor (IRF) family members are linked to the progression of various cancers. However, the roles of IRFs in clear cell renal cell carcinoma (ccRCC) remain undefined. Herein, we conducted a comprehensive analysis using the bioinformatics method to evaluate the expression patterns, clinical significance, and regulation of IRFs-related mechanisms in patients with ccRCC.

Methods

Data from the Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGA), and Gene Expression Omnibus (GEO) databases were used for investigation comprehensively. Specifically, we carried out a series of analyses to identify the candidate IRF and to explore its potential action mechanisms using the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. What is more, we emphatically investigate the association of candidate IRF with tumor immunity in ccRCC through the CIBERSORT algorithm, TIMER and GEPIA databases.

Results

Herein, IRF3 was identified as candidate IRF, which was highly expressed in ccRCC, and its overexpression was significantly associated with worse clinical outcomes and adverse overall survival. Uni- and multi-variate Cox regression analysis demonstrated that IRF3 overexpression was an independent predictor of worse prognosis. Functional enrichment analysis showed that IRF3 might participate in several cancer-related biological processes and signaling pathways, thereby promoting the progression of ccRCC. Additionally, we found that IRF3 was remarkably associated with tumor-infiltrating immune cells (TIICs) and various immune-related genes.

Conclusion

Herein, we identified IRF3 from the IRF gene family members, which could serve as promising prognostic marker and therapeutic target in ccRCC.

Opportunities and Challenges of Liquid Biopsy in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system, encompassing different entities with distinct histological features and clinical behavior. The diagnostic definition, therapeutic approach, and follow-up of thyroid cancers display some controversial aspects that represent unmet medical needs. Liquid biopsy is a non-invasive approach that detects and analyzes biological samples released from the tumor into the bloodstream. With the use of different technologies, tumor cells, free nucleic acids, and extracellular vesicles can be retrieved in the serum of cancer patients and valuable molecular information can be obtained. Recently, a growing body of evidence is accumulating concerning the use of liquid biopsy in thyroid cancer, as it can be exploited to define a patient's diagnosis, estimate their prognosis, and monitor tumor recurrence or treatment response. Indeed, liquid biopsy can be a valuable tool to overcome the limits of conventional management of thyroid malignancies. In this review, we summarize currently available data about liquid biopsy in differentiated, poorly differentiated/anaplastic, and medullary thyroid cancer, focusing on circulating tumor cells, circulating free nucleic acids, and extracellular vesicles.

Optimal Response in a Patient With CML Expressing BCR-ABL1 E6A2 Fusion Transcript With Nilotinib Therapy: A Case Report

BACKGROUND/AIM

The Philadelphia chromosome is considered the hallmark of chronic myeloid leukemia (CML). However, although most patients with CML are diagnosed with the e13a2 or e14a2 breakpoint cluster region (BCR)-Abelson 1 (ABL1) fusion transcripts, about 5% of them carry rare BCR-ABL1 fusion transcripts, such as e19a2, e8a2, e13a3, e14a3, e1a3 and e6a2. In particular, the e6a2 fusion transcript has been associated with clinically aggressive disease frequently presenting in accelerated or blast crisis phases; there is limited evidence on the efficacy of front-line second-generation tyrosine kinase inhibitors for this genotype.

CASE REPORT

We describe a case of atypical BCR-ABL1 e6a2 fusion transcript in a 46-year-old woman with CML.

RESULTS

The use of primers recognizing more distant exons from the common BCR-ABL1 breakpoint region correctly identified the atypical BCR-ABL1 e16a2 fusion transcript. Treatment with second-generation tyrosine kinase inhibitor nilotinib was effective in this patient expressing the atypical e6a2 BCR-ABL1 fusion transcript.

[The role of molecular testing in thyroid tumors]

¹I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia; ²Endocrinology Research Centre, Moscow, Russia Thyroid cancer is the most common endocrine gland cancer. In the last few decades, the molecular diagnostics for thyroid tumors have been widely researched. It is one of the few cancers whose incidence has increased in recent years from microcarcinomas to common, large forms, in all age groups, from children to the elder people. Most researches focus on the genetic basis, since our current knowledge of the genetic background of various forms of thyroid cancer is far from being complete. Molecular and genetic research has several main directions: firstly, differential diagnosis of thyroid tumors, secondly, the prognostic value of detected mutations in thyroid cancer, and thirdly, targeted therapy for aggressive or radioactive iodine-resistant forms of thyroid cancer. In this review, we wanted to update our understanding and describe the prevailing advances in molecular genetics of thyroid cancer, focusing on the main genes associated with the pathology and their potential application in clinical practice.

miR-587 promotes cervical cancer by repressing interferon regulatory factor 6

BACKGROUND

Interferon regulatory factor 6 (IRF6) exhibits tumor-suppressive functions in several cancer types. In the present study, the antitumor properties and related pathway mechanism of IRF6 were investigated in cervical cancer.

METHODS

Forty-one pairs of cervical cancer specimens and para-carcinoma tissues were collected to evaluate IRF6 expression using immunohistochemical staining and miR-587. The effects of miR-587 and IRF6 on cervical cancer cell growth were explored by MTT assays and in a HeLa tumor xenograft mouse model. The migration and invasion of cervical cancer cells were monitored using transwell assays.

RESULTS

IRF6 expression in cervical cancer specimens and cell lines was significantly reduced compared to that in the corresponding control group. In addition, IRF6 expression was negatively correlated with miR-587 in cervical cancer tissues. Bioinformatics algorithms and luciferase assays revealed that IRF6 is a potential target of miR-587, and miR-587 mimic transfection led to a significant repression of IRF6 protein levels in cervical cancer cells. We also discovered that the antineoplastic properties of IRF6 could be reversed by overexpressing miR-587 in cervical cancer cells. The up-regulation of miR-587 was correlated with poor overall survival in cervical cancer. In an in vivo experiment, miR-587 silencing induced HeLa tumor growth inhibition, which was associated with the up-regulation of IRF6 protein in the tumor.

CONCLUSIONS

miR-587 post-transcriptionally represses IRF6 protein expression to abrogate the antineoplastic activity of IRF6. The miR-587/IRF6 signaling pathway plays a crucial role in the progression of cervical cancer and serves as a potential therapeutic target for the treatment of cervical cancer.

Human FBXL8 Is a Novel E3 Ligase Which Promotes BRCA Metastasis by Stimulating Pro-Tumorigenic Cytokines and Inhibiting Tumor Suppressors

The initiation and progression of breast cancer (BRCA) is associated with inflammation and immune-overactivation, which is critically modulated by the E3 ubiquitin ligase. However, the underlying mechanisms and key factors involved in BRCA formation and disease advancement remains under-explored. By retrospective studies of BRCA patient tissues; and gene knockdown and gain/loss-of-function studies, we uncovered a novel E3 ligase, FBXL8, in BRCA. A signature expression profile of F-box factors that specifically target and degrade proteins involved in cell death/survival, was identified. FBXL8 emerged as a prominent member of the F-box factors. Ex vivo analysis of 1349 matched BRCA tissues indicated that FBXL8 promotes cell survival and tumorigenesis, and its level escalates with BRCA progression. Knockdown of FBXL8 caused: (i) intrinsic apoptosis, (ii) inhibition of cell migration and invasion, (iii) accumulation of two tumor-suppressors, CCND2 and IRF5, and (iv) downregulation of cancer-promoting cytokines/chemokines; all of which curtailed the tumor microenvironment and displayed potential to suppress cancer progression. Co-IP study suggests that two tumor-suppressors, CCND2 and IRF5 are part of the immune-complex of FBXL8. The protein levels of CCND2 and IRF5 inversely correlated with FBXL8 expression, implying that FBXL8 E3 ligase was associated with the degradation of CCND2 and IRF5. Altogether, we propose the exploitation of the ubiquitin signaling axis of FBXL8-CCND2-IRF5 for anti-cancer strategies and potential therapeutics.

The Reciprocal Interaction Between LncRNA CCAT1 and miR-375-3p Contribute to the Downregulation of IRF5 Gene Expression by Solasonine in HepG2 Human Hepatocellular Carcinoma Cells

Solasonine (SS), a natural glycoalkaloid component, has been shown to have potent inhibitory activity and cytotoxicity against many cancer types. However, the precise mechanisms underlying this, particularly in hepatocellular carcinoma (HCC) are poorly understood. In this study, we showed that SS inhibited growth of HCC cells. Mechanistically, we observed that SS increased the expression of miR-375-3p, whereas reducing levels of long non-coding RNAs (lncRNAs) CCAT1 was noticed in HepG2 HCC and other cells. In addition, we found that SS repressed transcription factors, SP1 and interferon regulatory factor 5 (IRF5), protein expressions. There was a reciprocal interaction among miR-375-3p, CCAT1, and SP1. Moreover, SS inhibited IRF5 promoter activity, which was not observed in cells transfected with excessive expressed SP1 vectors. Interestingly, exogenously expressed IRF5 was shown to reverse expressions of SS-inhibited CCAT1 and induced-miR-375-3p; and neutralized SS-inhibited growth of HCC cells. Similar results were also found in vivo mouse model. Collectively, our results show that SS inhibits HepG2 HCC growth through the reciprocal regulation between the miR-375-3p and lncRNA CCAT1, and this results in transcription factor SP1-mediated reduction of IRF5 expression. The regulations and interactions among miR-375-3p, CCAT1, SP1, and IRF5 axis unveil a novel molecular mechanism underlying the anti-HCC growth by SS. IRF5 may be a potential target for treatment of HCC.

Molecular Alterations in Thyroid Cancer: From Bench to Clinical Practice

Thyroid cancer comprises different clinical and histological entities. Whereas differentiated (DTCs) malignancies are sensitive to radioiodine therapy, anaplastic (ATCs) and medullary (MTCs) tumors do not uptake radioactive iodine and display aggressive features associated with a poor prognosis. Moreover, in a majority of DTCs, disease evolution leads to the progressive loss of iodine sensitivity. Hence, iodine-refractory DTCs, along with ATCs and MTCs, require alternative treatments reflective of their different tumor biology. In the last decade, the molecular mechanisms promoting thyroid cancer development and progression have been extensively studied. This has led to a better understanding of the genomic landscape, displayed by thyroid malignancies, and to the identification of novel therapeutic targets. Indeed, several pharmacological compounds have been developed for iodine-refractory tumors, with four multi-target tyrosine kinase inhibitors already available for DTCs (sorafenib and lenvatinib) and MTCs (cabozantib and vandetanib), and a plethora of drugs currently being evaluated in clinical trials. In this review, we will describe the genomic alterations and biological processes intertwined with thyroid cancer development, also providing a thorough overview of targeted drugs already tested or under investigation for these tumors. Furthermore, given the existing preclinical evidence, we will briefly discuss the potential role of immunotherapy as an additional therapeutic strategy for the treatment of thyroid cancer.

Transcription factor E2F1 positively regulates interferon regulatory factor 5 expression in non-small cell lung cancer

Purpose

Lung cancer is the most common malignant tumor in the world, and its incidence and mortality are very high. This study focuses on the mechanism of non-small cell lung cancer to find new therapeutic targets.

Methods

We used RT-PCR and Western blot to verify the linear relationship between E2F1 and IRF5 in normal lung tissue and lung cancer tissues. Secondly, we used overexpression and knock down E2F1 in cell lines to detect the expression of IRF5. The prime enzyme reporter plasmid verified that E2F1 binds to the core promoter region of IRF5; finally, CHIP experiments demonstrated that E2F1 binds directly to IRF5.

Results

We verified that E2F1 and IRF5 are decreased in patient tissues, and there is a strong linear relationship between E2F1 and IRF5. Secondly, we used overexpression of E2F1 or E2F1 siRNA transfected into HCC827 cells and found that E2F1 positively regulates the activity of the IRF5 promoter and the mRNA level of IRF5. Finally, the results of a chromatin immunoprecipitation assay demonstrated that E2F1 bound to the promoter region of IRF5 in vitro. These results suggested that the E2F1 transcription factor is the primary determinant for activating the basal transcription of the IRF5.

Conclusion

The transcription factor E2F1 positively regulates IRF5 in non-small cell lung cancer.

A promising role of interferon regulatory factor 5 as an early warning biomarker for the development of human non-small cell lung cancer

OBJECTIVES

Non-small cell lung cancer (NSCLC) accounts for 85%-90% of lung cancer cases and is a covert disease lacking early symptoms. Since cancer is recognised as an inflammation-associated condition, we analysed the relationship between the expression of interferon regulatory factor 5 (IRF5), a key transcription factor controlling inflammatory responses, and NSCLC development with the aim of identifying a warning biomarker for early diagnosis of the disease.

MATERIALS AND METHODS

The expression of IRF5 and its associated inflammatory factors IL-6, IL-10, IP-10, and TNF-α in the peripheral blood of NSCLC patients (n = 66) and healthy controls (n = 42) was analysed by quantitative RT-PCR, flow cytometry, and a cytometric bead array. IRF5 protein expression in NSCLC tissues (n = 102) was detected by Western blotting. The diagnostic value of IRF5 expression was determined by a receiver-operating characteristic (ROC) curve analysis.

RESULTS

The protein levels of IRF5, IL-6, and IP-10 were significantly higher in the peripheral blood of NSCLC patients than in that of healthy controls. IP-10 levels in plasma and IL-10 mRNA expression in white blood cells (WBCs) were significantly upregulated in early-stage NSCLC, whereas plasma IL-6 and IL-10 were elevated in the progressive stage. IRF5 protein levels in WBCs were positively correlated with plasma IP-10 but negatively correlated with plasma IL-10. Furthermore, the mRNA and protein levels of IRF5 in WBCs were significantly elevated in patients with early stage NSCLC compared to those in the progressive stage. Additionally, IRF5 protein levels were significantly lower in NSCLC tumour tissues than those in normal lung tissues.

CONCLUSIONS

IRF5 levels in WBCs can be significantly upregulated in early stage NSCLC and were shown to have diagnostic value as an early warning biomarker of NSCLC development.

Activation of the IGF Axis in Thyroid Cancer: Implications for Tumorigenesis and Treatment

The Insulin-like growth factor (IGF) axis is one of the best-established drivers of thyroid transformation, as thyroid cancer cells overexpress both IGF ligands and their receptors. Thyroid neoplasms encompass distinct clinical and biological entities as differentiated thyroid carcinomas (DTC)-comprising papillary (PTC) and follicular (FTC) tumors-respond to radioiodine therapy, while undifferentiated tumors-including poorly-differentiated (PDTC) or anaplastic thyroid carcinomas (ATCs)-are refractory to radioactive iodine and exhibit limited responses to chemotherapy. Thus, safe and effective treatments for the latter aggressive thyroid tumors are urgently needed. Despite a strong preclinical rationale for targeting the IGF axis in thyroid cancer, the results of the available clinical studies have been disappointing, possibly because of the crosstalk between IGF signaling and other pathways that may result in resistance to targeted agents aimed against individual components of these complex signaling networks. Based on these observations, the combinations between IGF-signaling inhibitors and other anti-tumor drugs, such as DNA damaging agents or kinase inhibitors, may represent a promising therapeutic strategy for undifferentiated thyroid carcinomas. In this review, we discuss the role of the IGF axis in thyroid tumorigenesis and also provide an update on the current knowledge of IGF-targeted combination therapies for thyroid cancer.

Chk1 Inhibition Restores Inotuzumab Ozogamicin Citotoxicity in CD22-Positive Cells Expressing Mutant p53

Inotuzumab ozogamicin (IO) is an anti-CD22 calicheamicin immunoconjugate that has been recently approved for the treatment of relapsed or refractory B-Acute Lymphoblastic Leukemia (r/r B-ALL). We employed both immortalized and primary cells derived from CD22-positive lymphoproliferative disorders to investigate the signaling pathways contributing to IO sensitivity or resistance. We found that the drug reduced the proliferation rate of CD22-positive cell lines expressing wild-type p53, but was remarkably less effective on cells exhibiting mutant p53. In addition, CD22-positive cells surviving IO were mostly blocked in the G2/M phase of the cell cycle because of Chk1 activation that, in the presence of a wild-type p53 background, led to p21 induction. When we combined IO with the Chk1 inhibitor UCN-01, we successfully abrogated IO-induced G2/M arrest regardless of the underlying p53 status, indicating that the DNA damage response triggered by IO is also modulated by p53-independent mechanisms. To establish a predictive value for p53 in determining IO responsiveness, we expressed mutant p53 in cell lines displaying the wild-type gene and observed an increase in IO IC₅₀ values. Likewise, overexpression of an inducible wild-type p53 in cells natively presenting a mutant protein decreased their IC₅₀ for IO. These results were also confirmed in primary CD22-positive cells derived from B-ALL patients at diagnosis and from patients with r/r B-ALL. Furthermore, co-treatment with IO and UCN-01 significantly increased cell death in primary cells expressing mutant p53. In summary, our findings suggest that p53 status may represent a biomarker predictive of IO efficacy in patients diagnosed with CD22-positive malignancies.

IRF5-mediated immune responses and its implications in immunological disorders

Transcription factors are gene regulators that activate or repress target genes. One family of the transcription factors that have been extensively studied for their crucial role in regulating gene network in the immune system is the interferon regulatory factors (IRFs). IRFs possess a novel turn-helix turn motif that recognizes a specific DNA consensus found in the promoters of many genes that are involved in immune responses. IRF5, a member of IRFs has recently gained much attention for its role in regulating inflammatory responses and autoimmune diseases. Here, we discuss the role of IRF5 in regulating immune cells functions and how the dysregulation of IRF5 contributes to the pathogenesis of immune disorders. We also review the latest findings of potential IRF5 inhibitors that modulate IRF5 activity in the effort of developing therapeutic approaches for treating inflammatory disorders.

Tumor Suppressor p53 Stimulates the Expression of Epstein-Barr Virus Latent Membrane Protein 1

Epstein-Barr virus (EBV) is associated with multiple human malignancies. EBV latent membrane protein 1 (LMP1) is required for the efficient transformation of primary B lymphocytes in vitro and possibly in vivo The tumor suppressor p53 plays a seminal role in cancer development. In some EBV-associated cancers, p53 tends to be wild type and overly expressed; however, the effects of p53 on LMP1 expression is not clear. We find LMP1 expression to be associated with p53 expression in EBV-transformed cells under physiological and DNA damaging conditions. DNA damage stimulates LMP1 expression, and p53 is required for the stimulation. Ectopic p53 stimulates endogenous LMP1 expression. Moreover, endogenous LMP1 blocks DNA damage-mediated apoptosis. Regarding the mechanism of p53-mediated LMP1 expression, we find that interferon regulatory factor 5 (IRF5), a direct target of p53, is associated with both p53 and LMP1. IRF5 binds to and activates a LMP1 promoter reporter construct. Ectopic IRF5 increases the expression of LMP1, while knockdown of IRF5 leads to reduction of LMP1. Furthermore, LMP1 blocks IRF5-mediated apoptosis in EBV-infected cells. All of the data suggest that cellular p53 stimulates viral LMP1 expression, and IRF5 may be one of the factors for p53-mediated LMP1 stimulation. LMP1 may subsequently block DNA damage- and IRF5-mediated apoptosis for the benefits of EBV. The mutual regulation between p53 and LMP1 may play an important role in EBV infection and latency and its related cancers.IMPORTANCE The tumor suppressor p53 is a critical cellular protein in response to various stresses and dictates cells for various responses, including apoptosis. This work suggests that an Epstein-Bar virus (EBV) principal viral oncogene is activated by cellular p53. The viral oncogene blocks p53-mediated adverse effects during viral infection and transformation. Therefore, the induction of the viral oncogene by p53 provides a means for the virus to cope with infection and DNA damage-mediated cellular stresses. This seems to be the first report that p53 activates a viral oncogene; therefore, the discovery would be interesting to a broad readership from the fields of oncology to virology.

IRF5 is associated with adverse postoperative prognosis of patients with non-metastatic clear cell renal cell carcinoma

BACKGROUND

IRF5 is one member of IRFs family, and is critical for host immunity and cell response. In the present study, we sought to search the clinical and prognostic value of IFR5 in patients with non-metastatic ccRCC.

RESULTS

IRF5 proved to be an adverse independent prognostic factor for overall survival (p < 0.001) and recurrence free survival (p = 0.002). The newly built nomograms could give better prediction for overall survival and recurrence free survival in ccRCC patients.

MATERIALS AND METHODS

We included 264 individuals who were diagnosed with non-metastatic clear cell renal cell carcinoma in the present study. Immunohistochemistry staining was performed on tissue microarrays to evaluate the IRF5 expression. χ2 test, Fisher's exact test, t test, Kaplan-Meier method and Cox proportional hazard model were applied to evaluate the prognostic value of IRF5. Two nomograms were constructed to predict clinical outcomes for ccRCC patients after surgery.

CONCLUSIONS

IRF5 was an adverse independent prognostic factor for both overall survival and recurrence free survival in patients with non-metastatic ccRCC.

New Insights in Thyroid Cancer and p53 Family Proteins

Thyroid cancers are common endocrine malignancies that comprise tumors with different clinical and histological features. Indeed, papillary and follicular thyroid cancers are slow-growing, well-differentiated tumors, whereas anaplastic thyroid cancers are undifferentiated neoplasias that behave much more aggressively. Well-differentiated thyroid carcinomas are efficiently cured by surgery and radioiodine, unlike undifferentiated tumors that fail to uptake radioactive iodine and are usually resistant to chemotherapy. Therefore, novel and more effective therapies for these aggressive neoplasias are urgently needed. Whereas most genetic events underlying the pathogenesis of well-differentiated thyroid cancers have been identified, the molecular mechanisms that generate undifferentiated thyroid carcinomas are still unclear. To date, one of the best-characterized genetic alterations leading to the development of poorly differentiated thyroid tumors is the loss of the p53 tumor suppressor gene. In addition, the existence of a complex network among p53 family members (p63 and p73) and their interactions with other factors that promote thyroid cancer progression has been well documented. In this review, we provide an update on the current knowledge of the role of p53 family proteins in thyroid cancer and their possible use as a therapeutic target for the treatment of the most aggressive variants of this disease.

Expression of interferon regulatory factor 5 is regulated by the Sp1 transcription factor

The transcription factor, interferon regulatory factor 5 (IRF5), is important in the induction of type I interferon, proinflammatory cytokines and chemokines, and is involved in autoimmune diseases and tumourigenesis. However, the mechanisms underlying the transcriptional regulation of wild‑type IRF5 remain to be fully elucidated. The present study was primarily designed to clarify whether specificity protein 1 (Sp1) was involved in the regulation of IRF5. Initially, the IRF5 promoter region was cloned and its promoter activity was examined using Hela and HEK 293 cells. Deletion analyses revealed that the region spanning ‑179 to +62 was the minimal promoter of IRF5. Bioinformatics analyses showed that this region contained three putative Sp1 binding sites, and mutational analyses revealed that all the Sp1 sites contributed to transcriptional activity. Secondly, the overexpression of Sp1 was found to increase the activity of the IRF5 promoter and the mRNA level of IRF5, determined using reporter gene assays and polymerase chain reaction analysis, respectively. By contrast, treatment with mithramycin and Sp1 small interfering RNA significantly reduced the activity of the IRF5 promoter and the mRNA level of IRF5. Finally, the results of an electrophoretic mobility shift assay and a chromatin immunoprecipitation assay demonstrated that Sp1 bound to the promoter region of IRF5 in vitro and in vivo. These results suggested that the Sp1 transcription factor is the primary determinant for activating the basal transcription of the IRF5.

Effect of BMAP-28 on human thyroid cancer TT cells is mediated by inducing apoptosis

Thyroid cancer is the most common malignant endocrine tumor, with significant morbidity and mortality. Bovine myeloid antimicrobial peptide 28 (BMAP-28) is a cathelicidin that is found in bovine neutrophils. In the present study, the effect and relative mechanism of BMAP-28 on the human thyroid cancer TT cell line in vitro and in vivo were investigated. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and a TT-xenograft mouse model were used in this study. The data obtained indicated that BMAP-28 significantly inhibited the proliferation of the TT cells in vitro. In addition, the Annexin V-fluorescein isothiocyanate/propidium iodide assay detected that BMAP-28 induced apoptotic effects in the TT cells. Moreover, the expression of activated caspase-3 and -9 was upregulated at the transcriptional and translational levels. Simultaneously, the expression of matrix metalloproteinase (MMP)3 and MMP9 was downregulated following BMAP-28 treatment. Finally, BMAP-28 significantly prevented the tumor growth in the TT-xenograft mouse model. These results indicated that BMAP-28 could be a potential agent for the treatment of thyroid cancer.

Osteopontin enhances the expression of HOTAIR in cancer cells via IRF1

Osteopontin (OPN), a secreted phosphoglycoprotein, plays important roles in tumor growth, invasion, and metastasis for many types of cancers. The long, noncoding RNA HOTAIR has been strongly associated with the invasion and metastasis of cancer cells. In this study, we found that recombinant human OPN could induce HOTAIR expression in a time- and dose-dependent manner, and our data also showed that OPN transcriptionally activated the expression of HOTAIR in cancer cells. Furthermore, through chromatin immunoprecipitation and luciferase activity assays, we found that IRF1 could bind to the HOTAIR promoter region and decrease its transcriptional activity, and cellular overexpression of IRF1 downregulated the level of HOTAIR. The receptor CD44 has also been verified as a regulator of OPN-induced HOTAIR expression. Interestingly, our data demonstrated that OPN could regulate PI3K/AKT and IRF1 expression and signaling, thereby influencing the expression of HOTAIR. In hepatocellular carcinoma samples, levels of HOTAIR correlated with the expression of OPN and IRF1. We therefore conclude that OPN, as an extracellular matrix protein, can stimulate the expression of HOTAIR by attenuating the inhibitory effect of IRF1, and this results in promotion of the invasion and metastasis of cancer cells.

Differentiation of benign from malignant thyroid nodules with acoustic radiation force impulse technique

OBJECTIVE

The aim of our study was to assess the performance of acoustic radiation force impulse (ARFI) imaging to differentiate benign from malignant thyroid nodules.

METHODS

182 patients who needed thyroid surgery were examined. All patients and 50 healthy volunteers underwent ARFI sonoelastography, which quantitatively analysed the elasticity and hardness of the nodule's centre and periphery.

RESULTS

ARFI values showed a statistical significance between malignant nodules and benign nodules and common thyroid parenchyma, in both the centre and periphery of nodules (p < 0.01). There was no significant difference between benign nodules and common thyroid parenchyma in either the nodule's centre or periphery (p > 0.05). There was no significant difference between the nodule's centre and periphery of the elastic parameters in both the benign and malignant nodules. There was a statistically significant difference among the two areas (the central group and the peripheral group) under the receiver operating characteristic curve, and the optimal model was the peripheral group. For differentiation of malignant from benign nodules, the sensitivity and specificity were 96.3% and 96.2%, respectively, when 2.545 m s(-1) was chosen as a cut-off value in the peripheral group.

CONCLUSION

ARFI imaging may be helpful to differentiate benign nodules from malignant thyroid nodules. The selecting measurement position is important in ARFI imaging, and it has good diagnostic value in clinical applications.

ADVANCES IN KNOWLEDGE

This study shows the diagnostic contribution of ARFI imaging in thyroid lesions.

IRF5 is a target of BCR-ABL kinase activity and reduces CML cell proliferation

Interferon regulatory factor 5 (IRF5) modulates the expression of genes controlling cell growth and apoptosis. Previous findings have suggested a lack of IRF5 transcripts in both acute and chronic leukemias. However, to date, IRF5 expression and function have not been investigated in chronic myeloid leukemia (CML). We report that IRF5 is expressed in CML cells, where it interacts with the BCR-ABL kinase that modulates its expression and induces its tyrosine phosphorylation. Tyrosine-phosphorylated IRF5 displayed reduced transcriptional activity that was partially restored by imatinib mesylate (IM). Interestingly, a mutant devoid of a BCR-ABL consensus site (IRF5(Y104F)) still presented significant tyrosine phosphorylation. This finding suggests that the oncoprotein phosphorylates additional tyrosine residues or induces downstream signaling pathways leading to further IRF5 phosphorylation. We also found that ectopic expression of IRF5 decreases the proliferation of CML cell lines by slowing their S-G2 transition, increasing the inhibition of BCR-ABL signaling and enhancing the lethality effect observed after treatment with IM, α-2-interferon and a DNA-damaging agent. Furthermore, IRF5 overexpression successfully reduced the clonogenic ability of CML CD34-positive progenitors before and after exposure to the above-indicated cytotoxic stimuli. Our data identify IRF5 as a downstream target of the BCR-ABL kinase, suggesting that its biological inactivation contributes to leukemic transformation.