Wilms tumor and the WT1 gene

LMO family gene polymorphisms and Wilms tumor susceptibility in Chinese children: a five-center case-control study

BACKGROUND

Wilms tumor is the most prevalent embryonal kidney malignancy in children worldwide. Previous genome-wide association study (GWAS) identified that LIM domain only 1 (LMO1) gene polymorphisms affected the susceptibility to develop certain tumor types. Apart from LMO1, the LMO gene family members also include LMO2-4, each of which has oncogenic potential.

METHODS

We conducted this five-center case‒control study to assess the correlations between single nucleotide polymorphisms in LMO family genes and Wilms tumor susceptibility. Odds ratios and 95% confidence intervals were calculated to evaluate the strength of the association.

RESULTS

We found LMO1 rs2168101 G > T and rs11603024 C > T as well as LMO2 rs7933499 G > A were significantly associated with Wilms tumor risk. Stratified analysis demonstrated a protective role of rs2168101 GT/TT genotypes against Wilms tumor in the subgroups of age ≤ 18 months, males and clinical stages I/II compared to the rs2168101 GG genotype. Nevertheless, carriers with the rs11603024 TT genotype were more likely to have an increased risk of Wilms tumor than those with rs11603024 CC/CT genotypes in age > 18 months. And the rs11603024 was identified as a protective polymorphism for reducing the risk of Wilms tumor in the sex- and gender- subgroup. Likewise, carriers with the rs7933499 GA/AA genotypes were at significantly elevated risk of Wilms tumor in age ≤ 18 months and clinical stages I/II.

CONCLUSION

Overall, our study identified the importance of LMO family gene polymorphisms on Wilms tumor susceptibility in Chinese children. Further investigations are needed to validate our conclusions.

Nephrotic Syndrome Throughout Childhood: Diagnosing Podocytopathies From the Womb to the Dorm

The etiologies of podocyte dysfunction that lead to pediatric nephrotic syndrome (NS) are vast and vary with age at presentation. The discovery of numerous novel genetic podocytopathies and the evolution of diagnostic technologies has transformed the investigation of steroid-resistant NS while simultaneously promoting the replacement of traditional morphology-based disease classifications with a mechanistic approach. Podocytopathies associated with primary and secondary steroid-resistant NS manifest as diffuse mesangial sclerosis, minimal change disease, focal segmental glomerulosclerosis, and collapsing glomerulopathy. Molecular testing, once an ancillary option, has become a vital component of the clinical investigation and when paired with kidney biopsy findings, provides data that can optimize treatment and prognosis. This review focuses on the causes including selected monogenic defects, clinical phenotypes, histopathologic findings, and age-appropriate differential diagnoses of nephrotic syndrome in the pediatric population with an emphasis on podocytopathies.

A rare case of extrarenal Wilms tumor of the uterine corpus: comprehensive genomic profile and review of the literature

Wilms tumor (WT), or nephroblastoma, is an uncommon malignant neoplasm occurring in the kidney of pediatric patients. Its extrarenal location is extremely rare and has been reported in various sites, including the female genital tract, with only 9 cases arising in the uterine corpus. We present the case of an adult woman who underwent total abdominal hysterectomy due to a uterine mass causing persistent abdominal pain. The characteristic triphasic morphology (composed of epithelial, stromal, and blastemal elements) supported by a broad immunohistochemical panel, along with the imaging exclusion of a renal neoplasm, was diagnostic of WT of the uterus. For the first time, a comprehensive genomic profiling of a uterine primary WT was also performed by next-generation sequencing, disclosing alterations at the level of copy number variations in the genes ERBB2, FGFR23, FGF6, FGFR2, and RPS6KB1. All previously reported uterine cases were reviewed, with a summary of their main clinicopathologic characteristics, and the main differential diagnoses are presented. Further reports are needed to improve our knowledge about prognostic factors, clinical behavior and molecular alterations that could guide appropriate therapeutic decision making.

Identification of m6A-associated genes as prognostic and immune-associated biomarkers in Wilms tumor

OBJECTIVES

Wilms tumor (WT) is a common renal malignant tumor in children. We aimed to investigate the potential prognostic value of m6A-related genes and their relationship to the immune microenvironment in WT.

METHODS

RNA-seq data and clinical information from 121 WT and 6 normal samples were obtained from the University of California Santa Cruz Xena database. We used various bioinformatics analysis tools to analyze these data and verify the expression level of m6A-related genes by experiments.

RESULTS

Four m6A-related genes were successfully screened, including ADGRG2, CPD, CTHRC1, and LRTM2. Kaplan-Meier survival curves showed that the four genes were closely related to the prognosis of WT, which was also confirmed by receiver operator characteristic curves. Subsequently, in the immune microenvironment of WT, we discovered that Th1_cells were positively correlated with ADGRG2, CCR was negatively correlated with CPD, CCR was positively correlated with CTHRC1, APC_co_stimulation, CCR, Macrophages, inflammation-promoting cells, Treg, and Type_II_IFN_Reponse were negatively correlated with LRTM2. Finally, qRT-PCR showed that expression levels of the four genes were upregulated in the nephroblastoma cell lines (G-401, SK-NEP-1, and WT-CLS1) compared with the human embryonic kidney cell lines (293T).

CONCLUSIONS

Taken together, our study first time screened the m6A-related genes and revealed that ADGRG2, CPD, CTHRC1, and LRTM2 are the prognostic and immune-associated biomarkers in WT.

The application, safety, and future of ex vivo immune cell therapies and prognosis in different malignancies

Introduction

Immunotherapy has revolutionized how cancer is treated. Many of these immunotherapies rely on ex vivo expansion of immune cells, classically T cells. Still, several immunological obstacles remain, including tumor impermeability by immune cells and the immunosuppressive nature of the tumor microenvironment (TME). Logistically, high costs of treatment and variable clinical responses have also plagued traditional T cell-based immunotherapies.

Methods

To review the existing literature on cellular immunotherapy, the PubMed database was searched for publications using variations of the phrases "cancer immunotherapy", "ex vivo expansion", and "adoptive cell therapy". The Clinicaltrials.gov database was searched for clinical trials related to ex vivo cellular therapies using the same phrases. The National Comprehensive Cancer Network guidelines for cancer treatment were also referenced.

Results

To circumvent the challenges of traditional T cell-based immunotherapies, researchers have developed newer therapies including tumor infiltrating lymphocyte (TIL), chimeric antigen receptor (CAR), T cell receptor (TCR) modified T cell, and antibody-armed T cell therapies. Additionally, newer immunotherapeutic strategies have used other immune cells, including natural killer (NK) and dendritic cells (DC), to modulate the T cell immune response to cancers. From a prognostic perspective, circulating tumor cells (CTC) have been used to predict cancer morbidity and mortality.

Conclusion

This review highlights the mechanism and clinical utility of various types of ex vivo cellular therapies in the treatment of cancer. Comparing these therapies or using them in combination may lead to more individualized and less toxic chemotherapeutics.

The tumor microenvironment and immune targeting therapy in pediatric renal tumors

This review highlights the role of several immunomodulating elements contributing to the tumor microenvironment of various pediatric renal tumors including Wilms tumor. The roles of innate and adaptive immune cells in renal tumors are summarized as well as immunomodulatory cytokines and other proteins. The expression and the predictive role of checkpoint modulators like PD-L1 and immunomodulating proteins like glypican-3, B7-H3, COX-2 are highlighted with a translational view toward potential therapeutic innovations. We further discuss the current state of preclinical models in advancing this field of study. Finally, examples of clinical trials of immunomodulating strategies such as monoclonal antibodies and chimeric antigen receptor T (CAR-T) cells for relapsed/refractory/progressive pediatric renal tumors are described.

Alternative RNA Splicing Defects in Pediatric Cancers: New Insights in Tumorigenesis and Potential Therapeutic Vulnerabilities

BACKGROUND

Compared to adult cancers, pediatric cancers are uniquely characterized by a genomically stable landscape and lower tumor mutational burden. However, alternative splicing, a global cellular process that produces different mRNA/protein isoforms from a single mRNA transcript, has been increasingly implicated in the development of pediatric cancers.

DESIGN

We review the current literature on the role of alternative splicing in adult cancer, cancer predisposition syndromes, and pediatric cancers. We also describe multiple splice variants identified in adult cancers and confirmed through comprehensive genomic profiling in our institutional cohort of rare, refractory and relapsed pediatric and adolescent young adult cancer patients. Finally, we summarize the contributions of alternative splicing events to neoantigens and chemoresistance and prospects for splicing-based therapies.

RESULTS

Published dysregulated splicing events can be categorized as exon inclusion, exon exclusion, splicing factor upregulation, or splice site alterations. We observe these phenomena in cancer predisposition syndromes (Lynch syndrome, Li-Fraumeni syndrome, CHEK2) and pediatric leukemia (B-ALL), sarcomas (Ewing sarcoma, rhabdomyosarcoma, osteosarcoma), retinoblastoma, Wilms tumor, and neuroblastoma. Within our institutional cohort, we demonstrate splice variants in key regulatory genes (CHEK2, TP53, PIK3R1, MDM2, KDM6A, NF1) that resulted in exon exclusion or splice site alterations, which were predicted to impact functional protein expression and promote tumorigenesis. Differentially spliced isoforms and splicing proteins also impact neoantigen creation and treatment resistance, such as imatinib or glucocorticoid regimens. Additionally, splice-altering strategies with the potential to change the therapeutic landscape of pediatric cancers include antisense oligonucleotides, adeno-associated virus gene transfers, and small molecule inhibitors.

CONCLUSIONS

Alternative splicing plays a critical role in the formation and growth of pediatric cancers, and our institutional cohort confirms and highlights the broad spectrum of affected genes in a variety of cancers. Further studies that elucidate the mechanisms of disease-inducing splicing events will contribute toward the development of novel therapeutics.

Myelin and lymphocyte protein serves as a prognostic biomarker and is closely associated with the tumor microenvironment in the nephroblastoma

Nephroblastoma, also known as Wilms' tumor (WT), is the most common renal tumor that occurs in children. Although the efficacy of treatment has been significantly improved by a series of comprehensive treatments, some patients still have poor prognosis. Myelin and lymphocyte (MAL) protein, a highly hydrophobic integrated membrane‐bound protein, has been implicated in many tumors and is also closely linked to kidney development. However, the relationship between MAL and WT has not yet been elucidated. Therefore, we attempted to evaluate the feasibility of MAL as a promising prognosis factor for WT. The differential expression of MAL was investigated using TARGET database and was verified using the Gene Expression Omnibus database and real‐time quantitative PCR. The prognostic ability of MAL was determined using Kaplan–Meier and Cox regression analyses. Pearson correlation analysis was applied to explore the relationship between MAL expression and methylation sites. The ESTIMATE and CIBERSORT algorithms showed that MAL expression was associated with the WT tumor microenvironment. Gene Set Enrichment Analysis (GSEA) indicated that multiple signaling pathways closely associated with tumorigenesis were differentially enriched between the high‐ and low‐MAL groups. In conclusion, our study comprehensively explored the potential of MAL as a prognosis factor for WT. Meanwhile, we also demonstrated that MAL, as a prognostic factor for WT, may be closely related to the tumor microenvironment.

WT1 and Cyclin D1 Immunohistochemistry: A Useful Adjunct for Diagnosis of Pediatric Small Round Blue Cell Tumors on Small Biopsies

Pediatric small round blue cell tumors (SRBCTs) are a heterogeneous group of neoplasms with overlapping morphological appearance. Accordingly, their diagnosis is one of the most difficult in the field of surgical pathology. The most common tumors include rhabdomyosarcoma, Ewing’s sarcoma, neuroblastoma, lymphoblastic lymphoma and Wilms’ tumor (the blastemal component). Over time their diagnosis has become more difficult due to the increasing use of small biopsies. However, the advent of immunohistochemistry has improved the quality of diagnosis in most cases by the application of an adequate panel of immunomarkers. Recently, WT1 and Cyclin D1 have been shown to be useful in the differential diagnosis of SRBCTs on surgically-resected specimens, showing a diffuse cytoplasmic positivity of the former in all RMSs and a diffuse nuclear staining of the latter in both EWS and NB. The aim of the present study was to investigate the expression of WT1 and Cyclin D1 on small biopsies from a series of 105 pediatric SRBCTs to evaluate their diagnostic utility. Both immunomarkers were differentially expressed, with a diffuse and strong cytoplasmic staining for WT1 limited to all cases of RMS, and a diffuse nuclear staining for cyclin D1 restricted to all cases of EWS and NB. Notably, the expression of WT1 and cyclin D1 was also retained in those cases in which the conventional tumor markers (myogenin, desmin and MyoD1 for RMS; CD99 for EWS; NB84 for NB) were focally expressed or more rarely absent. The present study shows that WT1 and Cyclin D1 are helpful immunomarkers exploitable in the differential diagnosis of pediatric SRBCTs on small biopsies, suggesting their applicability in routine practice.

Systematic review of the immunological landscape of Wilms tumors

Results of immunotherapy in childhood solid cancer have been so far, with the exception of neuroblastoma, quite disappointing. Lack of knowledge of the immune contexture of these tumors may have contributed to the failure of immunotherapies so far. Here, we systematically reviewed the literature regarding the immunology of Wilms tumor (WT), one of the most frequent pediatric solid tumors of the abdomen. In Wilms tumor patients the high cure rate of >90%, achieved by the combination of surgery and radio-chemotherapy, is at the expense of a high early and late toxicity. Moreover, treatment-resistant entities, such as diffuse anaplastic tumors or recurrent disease, still pose unsolved clinical problems. Successful immunotherapy could represent a novel and possibly less-toxic treatment option. Employing the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) method of literature search, we analyzed the current knowledge of the immunological landscape of Wilms tumors in terms of tumor microenvironment, prognostic implications of single biomarkers, and immunotherapy response.

RNA-binding proteins of COSMIC importance in cancer

Herculean efforts by the Wellcome Sanger Institute, the National Cancer Institute, and the National Human Genome Research Institute to sequence thousands of tumors representing all major cancer types have yielded more than 700 genes that contribute to neoplastic growth when mutated, amplified, or deleted. While some of these genes (now included in the COSMIC Cancer Gene Census) encode proteins previously identified in hypothesis-driven experiments (oncogenic transcription factors, protein kinases, etc.), additional classes of cancer drivers have emerged, perhaps none more surprisingly than RNA-binding proteins (RBPs). Over 40 RBPs responsible for virtually all aspects of RNA metabolism, from synthesis to degradation, are recurrently mutated in cancer, and just over a dozen are considered major cancer drivers. This Review investigates whether and how their RNA-binding activities pertain to their oncogenic functions. Focusing on several well-characterized steps in RNA metabolism, we demonstrate that for virtually all cancer-driving RBPs, RNA processing activities are either abolished (the loss-of-function phenotype) or carried out with low fidelity (the LoFi phenotype). Conceptually, this suggests that in normal cells, RBPs act as gatekeepers maintaining proper RNA metabolism and the "balanced" proteome. From the practical standpoint, at least some LoFi phenotypes create therapeutic vulnerabilities, which are beginning to be exploited in the clinic.

Maintenance of WT1 expression in tumor cells is associated with a good prognosis in malignant glioma patients treated with WT1 peptide vaccine immunotherapy

We have previously revealed the overexpression of Wilms' tumor gene 1 (WT1) in malignant glioma and developed WT1 peptide vaccine cancer immunotherapy. A phase II clinical trial indicated the clinical efficacy of the WT1 peptide vaccine for recurrent malignant glioma. Here, we aimed to investigate the immunological microenvironment in glioma tissues before and after WT1 peptide vaccine treatment. Paired tissue samples were obtained from 20 malignant glioma patients who had received the WT1 peptide vaccine for > 3 months and experienced tumor progression, confirmed radiographically and/or clinically, during vaccination. We discovered that the expression of WT1 and HLA class I antigens in the tumor cells significantly decreased after vaccination. Maintenance of WT1 expression, which is the target molecule of immunotherapy, in tumor cells during the vaccination period was significantly associated with a longer progression-free and overall survival. A high expression of HLA class I antigens and low CD4⁺/CD8⁺ tumor-infiltrating lymphocytes (TIL) ratio in pre-vaccination specimens, were also associated with a good prognosis. No statistically significant difference existed in the number of infiltrating CD3⁺ or CD8⁺ T cells between the pre- and post-vaccination specimens, whereas the number of infiltrating CD4⁺ T cells significantly decreased in the post-vaccination specimens. This study provides insight into the mechanisms of intra-tumoral immune reaction/escape during WT1 peptide vaccine treatment and suggests potential clinical strategies for cancer immunotherapy.

Wilms' Tumor 1 (WT1): A Novel Immunomarker of Dermatofibrosarcoma Protuberans-An Immunohistochemical Study on a Series of 114 Cases of Bland-Looking Mesenchymal Spindle Cell Lesions of the Dermis/Subcutaneous Tissues

Simple Summary

Dermatofibrosarcoma protuberans (DFSP) is a superficial fibroblastic spindle cell sarcoma with a high rate of local recurrence (20% to 50%) but with a low metastatic potential. DFSP is characterized by COL1A1-PDGFB gene fusion and diffuse immunohistochemical expression of CD34. This immunomarker is especially useful in distinguishing DFSP from its morphological mimickers, especially when pathologists are faced with small biopsies. Apart from CD34, there are no additional diagnostic immunomarkers for DFSP, and thus, there is the need to identify more sensitive and specific markers for this sarcoma. Recently, Wilms’ tumor 1 (WT1) has been shown to be diffusely expressed in the cytoplasm of several benign and malignant mesenchymal spindle cell lesions. Based on this background, the aim of this study is to evaluate the immunohistochemical expression of WT1 protein in a series of bland-looking spindle cell lesions of the dermis/subcutis, emphasizing its potential diagnostic role in identifying DFSP among its morphological mimickers.

Abstract

Purpose: to investigate the immunohistochemical expression and distribution of Wilms’ tumor 1 (WT1) (transcription factor produced by the tumor suppressor gene of the same name) in a series of 114 cases of bland-looking mesenchymal spindle cell lesions of the dermis/subcutaneous tissues to establish whether this immunomarker is differentially expressed in dermatofibrosarcoma protuberans (DFSP) versus its potential morphological mimickers. Methods: This retrospective multi-centric immunohistochemical study included 57 DFSP cases, 15 dermatofibromas, 5 deep fibrous histiocytomas, 8 neurofibromas, 5 spindle cell lipomas, 8 dermal scars, 6 nodular fasciitis, 5 cutaneous leiomyomas and 5 solitary fibrous tumors. Among the 57 DFSP cases, 11 were recurrent lesions; 2 non-recurrent cases exhibited an additional “fibrosarcomatous” overgrowth and 1 recurrent and 2 primary tumors contained a minority of “giant cell fibroblastoma” components. Results: Most DFSP (95% of cases) exhibited cytoplasmic staining for WT1; 11/11 residual/recurrent tumors showed diffuse and strong WT1 cytoplasmic immunoreactivity; apart from neurofibromas, WT1 expression was lacking in all the other cases studied. Conclusions: The cytoplasmic expression of WT1 may be exploitable as a complementary diagnostic immunomarker to CD34 in confirming the diagnosis of DFSP and to better evaluate the residual/recurrent tumor component.

Desmoplastic Small Round Cell Tumor of the Kidney: Report of a Case, Literature Review, and Comprehensive Discussion of the Distinctive Morphologic, Immunohistochemical, and Molecular Features in the Differential Diagnosis of Small Round Cell Tumors Affecting the Kidney

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive neoplasm typically presenting with widespread involvement of the abdominopelvic peritoneum of adolescent males, usually without organ-based primary. Although it is believed to originate from the serous (mainly peritoneal) membranes, intracranial, sinonasal, intraosseous, and other soft tissue sites are also documented. A chromosomal translocation t(11:22)(p13;q12) signature that fuses EWSR1 and WT1 genes results in the production of a chimeric protein with transcriptional regulatory activity that drives oncogenesis. Integration of clinical, morphologic, immunohistochemical, and genetic data is necessary to arrive at the correct diagnosis, especially when the tumor arises in an atypical site. A 15-year-old male presented with hematuria and was found to have a large renal tumor associated with adrenal, liver, lung, and bone metastases. Histopathologic and immunophenotypic features were distinctive for DSRCT. This diagnosis was confirmed by means of fluorescence in situ hybridization and cytogenetic analysis, which documented the pathognomonic t(11;22) translocation, and by reverse transcription polymerase chain reaction on snap-frozen tissue, which revealed the EWSR1/WT1-specific chimeric transcript. Despite high-dose chemotherapy and radiation therapy targeted to a single T11 vertebral metastasis, the disease progressed, and the patient died 4 years after the diagnosis. A search of electronic databases for DSRCT yielded 16 cases of well-documented renal primaries out of around 1570 cases from all sites gathered from the global literature. Desmoplastic small round blue cell tumor and other primary renal tumors considered in the differential diagnosis with DSRCT are discussed.

RNA Binding by the KTS Splice Variants of Wilms' Tumor Suppressor Protein WT1

Wilms' tumor suppressor protein WT1 regulates the expression of multiple genes through binding of the Cys₂-His₂ zinc finger domain to promoter sites. WT1 has also been proposed to be involved in post-transcriptional regulation, by binding to RNA using the same set of zinc fingers. WT1 has two major splice variants, where the Lys-Thr-Ser (KTS) tripeptide is inserted into the linker between the third and fourth zinc fingers. To obtain insights into the mechanism by which the different WT1 splice variants recognize both DNA and RNA, we have determined the solution structure of the WT1 (-KTS) zinc finger domain in complex with a 29mer stem-loop RNA. Zinc fingers 1-3 bind in a widened major groove favored by the presence of a bulge nucleotide in the double-stranded helical stem. Fingers 2 and 3 make specific contacts with the nucleobases in a conserved AUGG sequence in the helical stem. Nuclear magnetic resonance chemical shift mapping and relaxation analysis show that fingers 1-3 of the two splice variants (-KTS and +KTS) of WT1 form similar complexes with RNA. Finger 4 of the -KTS isoform interacts weakly with the RNA loop, an interaction that is abrogated in the +KTS isoform, and both isoforms bind with similar affinity to the RNA. In contrast, finger 4 is required for high-affinity binding to DNA and insertion of KTS into the linker of fingers 3 and 4 abrogates DNA binding. While finger 1 is required for RNA binding, it is dispensable for binding to consensus DNA sites.

Comprehensive bioinformatics analysis of the TP53 signaling pathway in Wilms' tumor

Background

Differential expression of tumor protein 53 (TP53, or p53) has been observed in multiple cancers. However, the expression levels and prognostic role of TP53 signaling pathway genes in Wilms' tumor (WT) have yet to be fully explored.

Methods

The expression levels of TP53 signaling pathway genes including TP53, mouse double minute 2 (MDM2), mouse double minute 4 (MDM4), cyclin-dependent kinase 2A (CDKN2A), cyclin-dependent kinase 2B (CDKN2B), and tumor suppressor p53-binding protein 1 (TP53BP1) in WT were analyzed using the Oncomine database. Aberration types, co-mutations, mutation locations, signaling pathways, and the prognostic role of TP53 in WT were investigated using cBioPortal. MicroRNA (miRNA) and transcription factor (TF) targets were identified with miRTarBase, miWalk, and ChIP-X Enrichment Analysis 3 (CheA3), respectively. A protein-protein network was constructed using GeneMANIA. The expression of TP53 signaling genes were confirmed in WT samples and normal kidney tissues using the Human Protein Atlas (HPA). Cancer Therapeutics Response Portal (CTRP) was used to analyze the small molecules potentially targeting TP53.

Results

TP53 was significantly expressed in the Cutcliffe Renal (P=0.010), but not in the Yusenko Renal (P=0.094). Meanwhile, MDM2 was significantly overexpressed in the Yusenko Renal (P=0.058), but not in the Cutcliffe Renal (P=0.058). The expression levels of MDM4 no significant difference between the tumor and normal tissue samples. The most common TP53 alteration was missense and the proportion of TP53 pathway-related mutations was 2.3%. Co-expressed genes included ZNF609 (zinc finger protein 609), WRAP53 (WD40-encoding RNA antisense to p53), CNOT2 (CC chemokine receptor 4-negative regulator of transcription 2), and CDH13 (cadherin 13). TP53 alterations indicated poor prognosis of WT (P=1.051e-4). The regulators of the TP53 pathway included miR-485-5p and TFs NR2F2 and KDM5B. The functions of TP53 signaling pathway were signal transduction in response to DNA damage and regulate the cell cycle. The small molecules targeting TP53 included PRIMA-1, RITA, SJ-172550, and SCH-529074.

Conclusions

TP53 was found to be differentially expressed in WT tissues. TP53 mutations indicated poor outcomes of WT. Therefore, pifithrin-mu, PRIMA-1, RITA, SJ-172550, and SCH-529074 could be used in combination with traditional chemotherapy to treat WT.

Comprehensive analysis of long non‑coding RNA using an associated competitive endogenous RNA network in Wilms tumor

Wilms tumor (WT) is the most common malignant renal neoplasm in children; however, the underlying molecular mechanisms are not well understood. According to the competing endogenous RNA (ceRNA) theory, long non-coding RNAs (lncRNAs) can regulate the expression of target genes by adsorbing microRNAs (miRNAs/miRs). However, the role of lncRNAs in WT has not been fully elucidated. The aim of the present study was to construct a ceRNA network to identify the potential lncRNAs involved in WT. The expression profiles of lncRNAs, miRNAs and mRNAs in 120 WT and six normal tissues were obtained from the Therapeutically Applicable Research to Generate Effective Treatments database. A total of 442 lncRNAs, 214 miRNAs and 4,912 mRNAs were identified as differentially expressed in WT and were enriched in 472 Gene Ontology terms (355 biological processes, 89 cellular components and 29 molecular functions) and 18 Kyoto Encyclopedia of Genes and Genomes pathways. A lncRNA-miRNA-mRNA ceRNA network of WT consisting of with 32 lncRNAs, 14 miRNAs and 158 mRNAs was constructed, based on the bioinformatics analysis of the miR target prediction database and the miRNAcode, miRTarBase and TargetScan databases. Subsequently, three lncRNAs, three miRNAs and 17 mRNAs, which had a significant effect on the overall survival rate of patients with WT, were identified based on the survival analysis. The three lncRNAs were also differentially expressed in the late and early stages of WT and were validated using the GSE66405 dataset obtained from the Gene Expression Omnibus database. In conclusion, the present study generated a specific lncRNA-related ceRNA network of WT, which may provide a novel perspective on the molecular mechanisms underlying the progression and prognosis of the disease.

Immunohistochemical Expression of Wilms’ Tumor 1 Protein in Human Tissues: From Ontogenesis to Neoplastic Tissues

The human Wilms’ tumor gene (WT1) was originally isolated in a Wilms’ tumor of the kidney as a tumor suppressor gene. Numerous isoforms of WT1, by combination of alternative translational start sites, alternative RNA splicing and RNA editing, have been well documented. During human ontogenesis, according to the antibodies used, anti-C or N-terminus WT1 protein, nuclear expression can be frequently obtained in numerous tissues, including metanephric and mesonephric glomeruli, and mesothelial and sub-mesothelial cells, while cytoplasmic staining is usually found in developing smooth and skeletal cells, myocardium, glial cells, neuroblasts, adrenal cortical cells and the endothelial cells of blood vessels. WT1 has been originally described as a tumor suppressor gene in renal Wilms’ tumor, but more recent studies emphasized its potential oncogenic role in several neoplasia with a variable immunostaining pattern that can be exclusively nuclear, cytoplasmic or both, according to the antibodies used (anti-C or N-terminus WT1 protein). With the present review we focus on the immunohistochemical expression of WT1 in some tumors, emphasizing its potential diagnostic role and usefulness in differential diagnosis. In addition, we analyze the WT1 protein expression profile in human embryonal/fetal tissues in order to suggest a possible role in the development of organs and tissues and to establish whether expression in some tumors replicates that observed during the development of tissues from which these tumors arise.

Cys2His2 Zinc Finger Methyl-CpG Binding Proteins: Getting a Handle on Methylated DNA

DNA methylation is an essential epigenetic modification involved in the maintenance of genomic stability, preservation of cellular identity, and regulation of the transcriptional landscape needed to maintain cellular function. In an increasing number of disease conditions, DNA methylation patterns are inappropriately distributed in a manner that supports the disease phenotype. Methyl-CpG binding proteins (MBPs) are specialized transcription factors that read and translate methylated DNA signals into recruitment of protein assemblies that can alter local chromatin architecture and transcription. MBPs thus play a key intermediary role in gene regulation for both normal and diseased cells. Here, we highlight established and potential structure-function relationships for the best characterized members of the zinc finger (ZF) family of MBPs in propagating DNA methylation signals into downstream cellular responses. Current and future investigations aimed toward expanding our understanding of ZF MBP cellular roles will provide needed mechanistic insight into normal and disease state functions, as well as afford evaluation for the potential of these proteins as epigenetic-based therapeutic targets.

Wilms tumour in children: 18 years of experience at Vilnius University Hospital Santaros Klinikos, Lithuania

Introduction

Wilms tumour (WT) is the most common childhood abdominal malignancy, with an average annual incidence of 1 in 10,000 children. The study published in 2002 reported lower survival rates of WT in Lithuania in comparison to the data of SIOP-9 study and the European Organization for Research and Treatment of Cancer (EORTC). We aimed to assess current diagnostic approach and treatment results of patients with WT treated at our institution and to compare the results with the previously published study.

Materials and methods

A retrospective single-centre study was performed. 48 patients with WT registered at the institutional data-base from 2000 to 2018 were enrolled. An estimated 5-year overall survival (OS_5y) and 2-year event-free survival (EFS_2y) by stage and risk groups was calculated using IBM SPSS. A comparative analysis of two time periods - 2000-2008 and 2009-2018 - was carried out.

Results

Forty-two (87.5%) patients presented with localised disease and 6 (12.5%) with primary metastatic disease. The majority of cases were of the intermediate-risk group (77%). The OS_5yof all analysed children was 86.4%. The EFS_2y was 88.9% in stage I, 91.7% in stage II, 83.3% in stage III, and 50% in stage IV. The EFS_2y was 100% in the low-risk group, 86.5% in the intermediate-risk group, and 25% in the high-risk group. Improvement of outcomes was observed over the analysed period: OS_5y changed from 81.0% in 2000-2008 to 92.6% in 2009-2018. Among 48 cases, ten patients showed recurrence: eight - early relapse and two - late relapse. Six patients died.

Conclusions

WT was diagnosed at early stages in most cases. The  survival was better among the  patients diagnosed in earlier stages and with favourable risk group. Better survival rates were observed in patients treated in 2009-2018 compared to the 2000-2008 period.

Role for first zinc finger of WT1 in DNA sequence specificity: Denys-Drash syndrome-associated WT1 mutant in ZF1 enhances affinity for a subset of WT1 binding sites

Wilms tumor protein (WT1) is a Cys2-His2 zinc-finger transcription factor vital for embryonic development of the genitourinary system. The protein contains a C-terminal DNA binding domain with four tandem zinc-fingers (ZF1-4). An alternative splicing of Wt1 can add three additional amino acids-lysine (K), threonine (T) and serine (S)-between ZF3 and ZF4. In the -KTS isoform, ZF2-4 determine the sequence-specificity of DNA binding, whereas the function of ZF1 remains elusive. Three X-ray structures are described here for wild-type -KTS isoform ZF1-4 in complex with its cognate DNA sequence. We observed four unique ZF1 conformations. First, like ZF2-4, ZF1 can be positioned continuously in the DNA major groove forming a 'near-cognate' complex. Second, while ZF2-4 make base-specific interactions with one DNA molecule, ZF1 can interact with a second DNA molecule (or, presumably, two regions of the same DNA molecule). Third, ZF1 can intercalate at the joint of two tail-to-head DNA molecules. If such intercalation occurs on a continuous DNA molecule, it would kink the DNA at the ZF1 binding site. Fourth, two ZF1 units can dimerize. Furthermore, we examined a Denys-Drash syndrome-associated ZF1 mutation (methionine at position 342 is replaced by arginine). This mutation enhances WT1 affinity for a guanine base. X-ray crystallography of the mutant in complex with its preferred sequence revealed the interactions responsible for this affinity change. These results provide insight into the mechanisms of action of WT1, and clarify the fact that ZF1 plays a role in determining sequence specificity of this critical transcription factor.

Immunotherapy of Relapsed and Refractory Solid Tumors With Ex Vivo Expanded Multi-Tumor Associated Antigen Specific Cytotoxic T Lymphocytes: A Phase I Study

PURPOSE

Tumor-associated antigen cytotoxic T cells (TAA-Ts) represent a new, potentially effective and nontoxic therapeutic approach for patients with relapsed or refractory solid tumors. In this first-in-human trial, we investigated the safety of administering TAA-Ts that target Wilms tumor gene 1, preferentially expressed antigen of melanoma, and survivin to patients with relapsed/refractory solid tumors.

MATERIALS AND METHODS

TAA-T products were generated from autologous peripheral blood and infused over three dose levels: 1, 2, and 4 × 10⁷ cells/m². Patients were eligible for up to eight infusions administered 4 to 7 weeks apart. We assessed dose limiting toxicity during the first 45 days after infusion. Disease response was determined within the context of a phase I trial.

RESULTS

There were no dose-limiting toxicities. Of 15 evaluable patients, 11 (73%) with stable disease or better at day 45 postinfusion were defined as responders. Six responders remain without progression at a median of 13.9 months (range, 4.1 to 19.9 months) after initial TAA-Ts. Patients who were treated at the highest dose level showed the best clinical outcomes, with a 6-month progression-free survival of 73% after TAA-T infusion compared with a 38% 6-month progression-free survival with prior therapy. Antigen spreading and a reduction in circulating tumor-associated antigens using digital droplet polymerase chain reaction was observed in patients after TAA-T infusion.

CONCLUSION

TAA-Ts safely induced disease stabilization, prolonged time to progression, and were associated with antigen spreading and a reduction in circulating tumor-associated antigen DNA levels in patients with relapsed/refractory solid tumors without lymphodepleting chemotherapy before infusion. TAA-Ts are a promising new treatment approach for patients with solid tumors.

The genetic changes of Wilms tumour

Wilms tumour is the most common renal malignancy of childhood. The disease is curable in the majority of cases, albeit at considerable cost in terms of late treatment-related effects in some children. However, one in ten children with Wilms tumour will die of their disease despite modern treatment approaches. The genetic changes that underpin Wilms tumour have been defined by studies of familial cases and by unbiased DNA sequencing of tumour genomes. Together, these approaches have defined the landscape of cancer genes that are operative in Wilms tumour, many of which are intricately linked to the control of fetal nephrogenesis. Advances in our understanding of the germline and somatic genetic changes that underlie Wilms tumour may translate into better patient outcomes. Improvements in risk stratification have already been seen through the introduction of molecular biomarkers into clinical practice. A host of additional biomarkers are due to undergo clinical validation. Identifying actionable mutations has led to potential new targets, with some novel compounds undergoing testing in early phase trials. Avenues that warrant further exploration include targeting Wilms tumour cancer genes with a non-redundant role in nephrogenesis and targeting the fetal renal transcriptome.

Zinc Finger Readers of Methylated DNA

DNA methylation is a prevalent epigenetic modification involved in regulating a number of essential cellular processes, including genomic accessibility and transcriptional outcomes. As such, aberrant alterations in global DNA methylation patterns have been associated with a growing number of disease conditions. Nevertheless, the full mechanisms by which DNA methylation information is interpreted and translated into genomic responses is not yet fully understood. Methyl-CpG binding proteins (MBPs) function as important mediators of this essential process by selectively reading DNA methylation signals and translating this information into down-stream cellular outcomes. The Cys₂His₂ zinc finger scaffold is one of the most abundant DNA binding motifs found within human transcription factors, yet only a few zinc finger containing proteins capable of conferring selectivity for mCpG over CpG sites have been characterized. This review summarizes our current structural understanding for the mechanisms by which the zinc finger MBPs evaluated to date read this essential epigenetic mark. Further, some of the biological implications for mCpG readout elicited by this family of MBPs are discussed.

A regulatory circuitry between miR-193a/miR-600 and WT1 enhances leukemogenesis in acute myeloid leukemia

The aberrant overexpression of Wilms tumor-1 (WT1) in acute myeloid leukemia (AML) plays an important role in blast cell survival by enhancing proliferation and inhibiting apoptosis. However, the mechanism underlying the overexpression of WT1 remains unclear. Here, we identified miR-193a (miR-193a-5p) and miR-600 targeting and degrading WT1. MiR-193a and miR-600 synergistically reduced WT1 expression and suppressed the activity of a luciferase reporter by binding coding sequence and the 3'-untranslated region of WT1 mRNA, respectively. Furthermore, the expression of miR-193a and miR-600 was decreased in AML patients compared with normal controls. DNA hypermethylation in pre-miR-193a promoter, but not pre-miR-600 promoter, caused the downregulation of miR-193a. Most intriguingly, ectopic expression of WT1 inhibited miR-600 expression, in turn, by binding the putative pre-miR-600 promoter, leading to the downregulation of miR-600 in AML blasts. Ectopic expression of miR-193a and miR-600 synergistically inhibited cell proliferation, induced apoptosis, and decreased colony formation in leukemia cells. Finally, overexpression of miR-193a and miR-600 decreased the growth of K562-inoculated tumor xenografts and extended survival time in THP1-transplanted leukemia mice. In conclusion, these data reveal an important role of miRNAs-WT1 circuitry in leukemia cells and the therapeutic promise of restoring miR-193a and miR-600 expression in AML patients.

Aberrant Global and Jagged-Mediated Notch Signaling Disrupts Segregation Between wt1-Expressing and Steroidogenic Tissues in Zebrafish

Although the zebrafish interrenal tissue has been used as a model for steroidogenesis and genesis of the adrenal gland, its specification and morphogenesis remains largely unclear. In the present study, we explored how the Wilms tumor 1 (WT1)-expressing cells are segregated from the SF-1-expressing steroidogenic cells in the zebrafish model. The interrenal tissue precursors expressing ff1b, the equivalent of mammalian SF-1, were derived from wt1-expressing pronephric primordia in the zebrafish embryo. Through histochemistry and in situ hybridization, we demonstrated that the size of functionally differentiated interrenal tissue was substantially increased on global inhibition of the Notch signaling pathway and was accompanied by a disrupted segregation between the wt1- and ff1b-expressing cells. As the Notch pathway was conditionally activated during interrenal specification, differentiation, but not ff1b expression, of interrenal tissue was drastically compromised. In embryos deficient for Notch ligands jagged 1b and 2b, transgenic reporter activity of wt1b promoter was detected within the steroidogenic interrenal tissue. In conclusion, our results indicate that Jagged-Notch signaling is required (1) for segregation between wt1-expressing cells and differentiated steroidogenic tissue; and (2) to modulate the extent of functional differentiation in the steroidogenic interrenal tissue.

A brief review of kidney development, maturation, developmental abnormalities, and drug toxicity: juvenile animal relevancy

Nonclinical juvenile animal tests perform a valuable role in determining adverse drug effects during periods of organogenesis and/or functional maturation. Developmental anatomic and functional maturation time points are important to consider between juveniles and adults when regarding different organ toxicities in response to drug administration. The kidney is an example of a major organ that has differences in these time points in comparing juveniles to adults and in contrasting humans to laboratory animal species. Toxicologic pathologists, involved in juvenile studies, need to be aware of these time points which are age-related exposure periods of sensitivity to drug toxicity. Age-related developmental anatomic and functional maturation are factors which can affect the way that a drug is absorbed, distributed, metabolized, and excreted (ADME). Changes to any component of ADME may alter drug toxicity resulting in kidney abnormalities, nephrotoxicity, or maturational disorders. Juvenile animal kidneys may either be less resistant or more resistant to known adult nephrotoxic drug effects. Furthermore, drug toxicity observed in juvenile animal kidneys may not always correspond to similar toxicities in humans. Juvenile animal nonclinical toxicology studies targeting the kidneys have to be carefully planned to attain the maximum knowledge from each study.

Assessment of Relationship between Wilms' Tumor Gene (WT1) Expression in Peripheral Blood of Acute Leukemia Patients and Serum IL-12 and C3 Levels

BACKGROUND

Leukemia is a common cancer among children and adolescents. Wilms' tumor gene (WT1) is highly expressed in patients with acute leukemia. It is found as a tumor associated antigen (TAA) in various types of hematopoietic malignancies and can be employed as a useful marker for targeted immunotherapy and monitoring of minimal residual disease (MRD). In this regard, WT1 is a transcription factor that promotes gene activation or repression depending on cellular and promoter context. The purpose of this study was assessment of WT1 gene expression in patients with acute leukemia, measurement of IL-12 and C3 levels in serum and evaluation of the relationship between them.

MATERIALS AND METHODS

We evaluated the expression of WT1 mRNA using real-time quantitative RT-PCR and serum levels of IL-12 and C3 using ELISA and nephelometry in peripheral blood of 12 newly diagnosed patients with acute leukemia and 12 controls.

RESULTS

The results of our study showed that the average wT1 gene expression in patients was 7.7 times higher than in healthy controls (P <0.05). In addition, IL-12 (P = 0.003) and C3 (P <0.0001) were significantly decreased in the test group compared to controls.

CONCLUSIONS

WT1 expression levels are significantly higher in patients compared with control subjects whereas serum levels of interleukin-12 and C3 are significantly lower in patients. Wt1 expression levels in patients are inversely related with serum levels of IL-12 and C3.

Denys-Drash syndrome associated WT1 glutamine 369 mutants have altered sequence-preferences and altered responses to epigenetic modifications

Mutations in human zinc-finger transcription factor WT1 result in abnormal development of the kidneys and genitalia and an array of pediatric problems including nephropathy, blastoma, gonadal dysgenesis and genital discordance. Several overlapping phenotypes are associated with WT1 mutations, including Wilms tumors, Denys-Drash syndrome (DDS), Frasier syndrome (FS) and WAGR syndrome (Wilms tumor, aniridia, genitourinary malformations, and mental retardation). These conditions vary in severity from individual to individual; they can be fatal in early childhood, or relatively benign into adulthood. DDS mutations cluster predominantly in zinc fingers (ZF) 2 and 3 at the C-terminus of WT1, which together with ZF4 determine the sequence-specificity of DNA binding. We examined three DDS associated mutations in ZF2 of human WT1 where the normal glutamine at position 369 is replaced by arginine (Q369R), lysine (Q369K) or histidine (Q369H). These mutations alter the sequence-specificity of ZF2, we find, changing its affinity for certain bases and certain epigenetic forms of cytosine. X-ray crystallography of the DNA binding domains of normal WT1, Q369R and Q369H in complex with preferred sequences revealed the molecular interactions responsible for these affinity changes. DDS is inherited in an autosomal dominant fashion, implying a gain of function by mutant WT1 proteins. This gain, we speculate, might derive from the ability of the mutant proteins to sequester WT1 into unproductive oligomers, or to erroneously bind to variant target sequences.

Expression profile of Wilms Tumor 1 (WT1) isoforms in undifferentiated and all-trans retinoic acid differentiated neuroblastoma cells

Wilms tumor 1 gene (WT1) is a tumor suppressor gene originally identified in nephroblastoma. It is also expressed in neuroblastoma which represents the most aggressive extracranial pediatric tumor. Many evidences have shown that neuroblastoma may undergo maturation, by transforming itself in a more differentiated tumors such as ganglioneuroblastoma and ganglioneuroma, or progressing into a highly aggressive metastatic malignancy. To date, 13 WT1 mRNA alternative splice variants have been identified. However, most of the studies have focused their attention only on isoform of ∼49 kDa. In the present study, it has been investigated the expression pattern of WT1 isoforms in an in vitro model of neuroblastoma consisting in undifferentiated or all-trans retinoic acid (RA) differentiated cells. These latter representing the less malignant phenotype of this tumor. Results have demonstrated that WT1.1-WT1.5, WT1.6-WT1.9, WT1.10 WT1.11-WT1.12 and WT1.13 isoforms are expressed in both groups of cells, but their levels are significantly increased after RA treatment. These data have also been confirmed by immunofluorescence analysis. Moreover, the inhibition of PI3K/Akt and MAPK/ERK, that represent two signalling pathway specifically involved in NB differentiation, induces an overexpression of WT1 isoforms. These data suggest that WT1 isoforms might be involved in differentiation of neuroblastic into mature ganglion cells.

[Nephroblastomas: Almost exclusively in clinical trials!]

Nephroblastomas are the most commonly occurring renal neoplasms in childhood and are treated almost exclusively in clinical trials. An important factor for further therapeutic management is the pathological evaluation of the nephrectomy specimen. Tumor stage and risk group classification are the most crucial parameters. An independent assessment of the tumor by a reference pathology center is an essential standard procedure. Although many molecular genetic discoveries have been made in nephroblastomas over recent years, molecular parameters do not (yet) play a role in treatment stratification.

The Role of WT1 in Embryonic Development and Normal Organ Homeostasis

The Wilms' tumor suppressor gene 1 (Wt1) is critically involved in a number of developmental processes in vertebrates, including cell differentiation, control of the epithelial/mesenchymal phenotype, proliferation, and apoptosis. Wt1 proteins act as transcriptional and post-transcriptional regulators, in mRNA splicing and in protein-protein interactions. Furthermore, Wt1 is involved in adult tissue homeostasis, kidney function, and cancer. For these reasons, Wt1 function has been extensively studied in a number of animal models to establish its spatiotemporal expression pattern and the developmental fate of the cells expressing this gene. In this chapter, we review the developmental anatomy of Wt1, collecting information about its dynamic expression in mesothelium, kidney, gonads, cardiovascular system, spleen, nervous system, lung, and liver. We also describe the adult expression of Wt1 in kidney podocytes, gonads, mesothelia, visceral adipose tissue, and a small fraction of bone marrow cells. We have reviewed the available animal models for Wt1-expressing cell lineage analysis, including direct Wt1 expression reporters and systems for permanent Wt1 lineage tracing, based on constitutive or inducible Cre recombinase expression under control of a Wt1 promoter. Finally we provide a number of laboratory protocols to be used with these animal models in order to assess reporter expression.

Regulation of catalase expression in healthy and cancerous cells

Catalase is an important antioxidant enzyme that dismutates hydrogen peroxide into water and molecular oxygen. The catalase gene has all the characteristics of a housekeeping gene (no TATA box, no initiator element sequence, high GC content in promoter) and a core promoter that is highly conserved among species. We demonstrate in this review that within this core promoter, the presence of DNA binding sites for transcription factors, such as NF-Y and Sp1, plays an essential role in the positive regulation of catalase expression. Additional transcription factors, such as FoxO3a, are also involved in this regulatory process. There is strong evidence that the protein Akt/PKB in the PI3K signaling pathway plays a major role in the expression of catalase by modulating the activity of FoxO3a. Over the past decade, other transcription factors (PPARγ, Oct-1, etc.), as well as genetic, epigenetic, and posttranscriptional processes, have emerged as crucial contributors to the regulation of catalase expression. Altered expression levels of catalase have been reported in cancer tissues compared to their normal counterparts. Deciphering the molecular mechanisms that regulate catalase expression could, therefore, be of crucial importance for the future development of pro-oxidant cancer chemotherapy.

WT1 expression is increased in primary fibroblasts derived from Dupuytren's disease tissues

Dupuytren's disease (DD) is a fibroproliferative and contractile fibrosis of the palmar fascia that, like all other heritable fibroses, is currently incurable. While DD is invariably benign, it exhibits some molecular similarities to malignant tumours, including increased levels of ß-catenin, onco-fetal fibronectin, periostin and insulin-like growth factor (IGF)-II. To gain additional insights into the pathogenesis of DD, we have assessed the expression of WT1, encoding Wilm's tumour 1, an established tumour biomarker that is syntenic with IGF2, the gene encoding IGF-II in humans. We found that WT1 expression is robustly and consistently up regulated in primary fibroblasts derived from the fibrotic palmar fascia of patients with DD (DD cells), whereas syngeneic fibroblasts derived from the macroscopically unaffected palmar fascia in these patients and allogeneic fibroblasts derived from normal palmar fascia exhibited very low or undetectable WT1 transcript levels. WT1 immunoreactivity was evident in a subset of cells in the fibrotic palmar fascia of patients with DD, but not in macroscopically unaffected palmar fascia. These findings identify WT1 expression as a novel biomarker of fibrotic palmar fascia and are consistent with the hypothesis that the pathogeneses of DD and malignant tumours have molecular similarities.

WT1 expression in the human fetus during development

Wilms’ Tumor 1 (WT1) is a transcription factor involved in the development of the urogenital system. The purpose of this study was to analyze the immunoreactivity for WT1 protein in different tissues and organs in human fetuses in early phases of gestation. To this end, samples from multiple organs were obtained from 4 human fetuses, ranging from 7 up to 12 weeks of gestation. Each sample was formalin-fixed, paraffin embedded and immunostained for WT1. Our data show that WT1 is involved in development of multiple human organs in a more vast series of cells types than previously reported. Immunostaining for WT1 was characterized by a predominant cytoplasmic reactivity in the vast majority of cell types. Mesenchimal progenitors in the fetal lung, ductal plate progenitors in fetal liver, cap mesenchimal cells in the developing kidney, fetal zone cells in adrenal glands, atrial and ventricular cardiomyocytes in the fetal heart, radial glial cells in the fetal cerebral cortex and skeletal muscle cell precursors showed the highest levels of WT1 immunoreactivity. Future studies will be needed to detect differences in the expression of WT1 in various organs at different gestational ages, in order to better evaluate the role of WT1 in cell proliferation and differentiation during intrauterine human development.

Non-clinical safety evaluation of repeated intramuscular administration of the AS15 immunostimulant combined with various antigens in rabbits and cynomolgus monkeys

Combination of tumor antigens with immunostimulants is a promising approach in cancer immunotherapy. We assessed animal model toxicity of AS15 combined with various tumor antigens: WT1 (rabbits), or p501, dHER2 and recPRAME (cynomolgus monkeys), administered in seven or 20 dose regimens versus a saline control. Clinical and ophthalmological examinations, followed by extensive post‐mortem pathological examinations, were performed on all animals. Blood hematology and biochemistry parameters were also assessed. Antigen‐specific antibody titers were determined by enzyme‐linked immunosorbent assay. Additional assessments in monkeys included electrocardiography and immunohistochemical evaluations of the p501 expression pattern. Transient increases in body temperature were observed 4 h or 24 h after injections of recPRAME + AS15 and dHER2 + AS15. Edema and erythema were observed up to 1 week after most injections of recPRAME + AS15 and all injections of dHER2 + AS15. No treatment‐related effects were observed for electrocardiography parameters. Mean fibrinogen levels were significantly higher in all treated groups compared to controls, but no differences could be observed at the end of the treatment‐free period. Transient but significant differences in biochemistry parameters were observed post‐injection: lower albumin/globulin ratios (p501 + AS15), and higher bilirubin, urea and creatinine (dHER2 + AS15). Pathology examinations revealed significant increases in axillary lymph node mean weights (recPRAME + AS15) compared to controls. A 100% seroconversion rate was observed in all treated groups, but not in controls. p501 protein expression was observed in prostates of all monkeys from studies assessing p501 + AS15. These results suggest a favorable safety profile of the AS15‐containing candidate vaccines, supporting the use of AS15 for clinical development of potential anticancer vaccines. Copyright © 2015 The Authors. Journal of Applied Toxicology Published by John Wiley & Sons Ltd.

The aim of the current paper was to assess the safety profile of vaccine candidates containing the AS15 immunostimulant combined with different antigens in two animal models. Several antigens were tested for this purpose: WT1 (rabbits), p501, dHER2 and recPRAME (cynomolgus monkeys). Only transient differences in hematology and biochemical parameters could be observed, while pathology testing revealed no safety concerns. Our findings support the use of AS15 for clinical development of potential immunotherapeutic cancer vaccines.

Wilms' tumor 1 (WT1) protein expression in human developing tissues

Several genes playing crucial roles in human development often reproduce a key role also during the onset and progression of malignant tumors. WT1, a transcription factor expressed with a dynamic pattern during human development, has either oncogenic or suppressor tumor properties. A detailed analysis of the immunohistochemical profile of WT1 protein in human developmental tissues could be exploitable as the rational for better understanding its role in cancerogenesis and planning innovative WT1-based therapeutic approaches. This review focuses on the dynamic immunohistochemical expression and distribution of WT1 protein during human ontogenesis, providing illustrations and discussion on the most relevant findings. The possibility that WT1 nuclear/cytoplasmic expression in some tumors mirrors its normal developmental regulation will be emphasized.

Wilms tumor 1 (WT1) protein: Diagnostic utility in pediatric tumors

Despite Wilms tumor 1 (WT1) protein was originally considered as a specific immunomarker of Wilms tumor, with the increasing use of immunohistochemistry, there is evidence that other tumors may share WT1 protein expression. This review focuses on the immunohistochemical profile of WT1 protein in the most common malignant tumors of children and adolescents. The variable expression and distribution patterns (nuclear vs cytoplasmic) in the different tumors, dependent on the antibodies used (anti-C or N-terminus WT1 protein), will be emphasized by providing explicative illustrations. Potential diagnostic pitfalls from unexpected WT1 protein expression in some tumors will be discussed in order to avoid diagnostic errors, especially when dealing with small biopsies.

Wilms' tumor gene 1 (WT1) silencing inhibits proliferation of malignant peripheral nerve sheath tumor sNF96.2 cell line

Wilms’ tumor gene 1 (WT1) plays complex roles in tumorigenesis, acting as tumor suppressor gene or an oncogene depending on the cellular context. WT1 expression has been variably reported in both benign and malignant peripheral nerve sheath tumors (MPNSTs) by means of immunohistochemistry. The aim of the present study was to characterize its potential pathogenetic role in these relatively uncommon malignant tumors. Firstly, immunohistochemical analyses in MPNST sNF96.2 cell line showed strong WT1 staining in nuclear and perinuclear areas of neoplastic cells. Thus, we investigated the effects of silencing WT1 by RNA interference. Through Western Blot analysis and proliferation assay we found that WT1 knockdown leads to the reduction of cell growth in a time- and dose-dependent manner. siWT1 inhibited proliferation of sNF96.2 cell lines likely by influencing cell cycle progression through a decrease in the protein levels of cyclin D1 and inhibition of Akt phosphorylation compared to the control cells. These results indicate that WT1 knockdown attenuates the biological behavior of MPNST cells by decreasing Akt activity, demonstrating that WT1 is involved in the development and progression of MPNSTs. Thus, WT1 is suggested to serve as a potential therapeutic target for MPNSTs.

EWS-WT1 oncoprotein activates neuronal reprogramming factor ASCL1 and promotes neural differentiation

The oncogenic fusion gene EWS-WT1 is the defining chromosomal translocation in desmoplastic small round-cell tumors (DSRCT), a rare but aggressive soft tissue sarcoma with a high rate of mortality. EWS-WT1 functions as an aberrant transcription factor that drives tumorigenesis, but the mechanistic basis for its pathogenic activity is not well understood. To address this question, we created a transgenic mouse strain that permits physiologic expression of EWS-WT1 under the native murine Ews promoter. EWS-WT1 expression led to a dramatic induction of many neuronal genes in embryonic fibroblasts and primary DSRCT, most notably the neural reprogramming factor ASCL1. Mechanistic analyses demonstrated that EWS-WT1 directly bound the proximal promoter of ASCL1, activating its transcription through multiple WT1-responsive elements. Conversely, EWS-WT1 silencing in DSRCT cells reduced ASCL1 expression and cell viability. Notably, exposure of DSRCT cells to neuronal induction media increased neural gene expression and induced neurite-like projections, both of which were abrogated by silencing EWS-WT1. Taken together, our findings reveal that EWS-WT1 can activate neural gene expression and direct partial neural differentiation via ASCL1, suggesting agents that promote neural differentiation might offer a novel therapeutic approach to treat DSRCT.

Wilms' tumor protein (WT1) in mammary myofibroblastoma: an immunohistochemical study

Wilms' tumor protein (WT1) has been immunohistochemically detected in the cytoplasm of some developing, adult normal and neoplastic human tissues, suggesting its complex regulator activity in transcriptional/translational processes. Among neoplastic tissues, WT1 has been documented in the cytoplasm of benign and malignant vascular tumors and in rhabdomyosarcoma, while there are no available studies about its expression in myofibroblastic tumors. Accordingly, we studied immunohistochemically the potential expression of WT1 in mammary myofibroblastoma (MFB), a prototypical myofibroblastic tumor. A series of 18 cases of mammary MFB, including several morphological variants (classic, fibrotic, myxoid, lipomatous, Schwannian-like, and epithelioid variants), were tested with antibodies against the N-terminal of WT1. The most striking finding was a diffuse and strong WT1 cytoplasmic immunostaining restricted to the "epithelioid cell MFB", a rare and diagnostically challenging variant. Conversely the other variants of MFB, including the classic-type, were negative or only focally positive. The present study shows that mammary epithelioid cell MFB should be added to the list of mesenchymal tumors which express WT1 in the cytoplasm of neoplastic cells. Accordingly, we suggest that the detection of WT1 cytoplasmic immunoreactivity is of complementary diagnostic value to conventional myofibroblastic markers in identifying epithelioid cell myofibroblastoma.

Exogenous expression of WT1 gene influences U937 cell biological behaviors and activates MAPK and JAK-STAT signaling pathways

Wilms' tumor 1 (WT1) gene plays important roles in leukemogenesis. To further explore its underlying mechanisms, we transfected two WT1 isoforms, WT1(+17AA/-KTS) and WT1(+17AA/+KTS) into U937, a WT1-null monoblastic cell line, studied their effects on migration, colony formation, apoptosis, gene expression and pertinent signaling pathways of U937 cells. The results showed that WT1(+17AA/-KTS), but not WT1(+17AA/+KTS), enhanced migration and colony forming abilities of U937 cells, and suppressed etoposide-induced U937 cell apoptosis. Transfection of WT1 isoforms activated gene expressions of chemokine, and induced up-regulation of signaling molecules involved in JAK-STAT and MAPK signaling pathways. This study showed that exogenous expression of WT1 gene remarkably affected biological behaviors of U937 cells, and these effects are possibly mediated by up-regulation of genes related to chemokine, JAK-STAT and MAPK signaling pathways.

S5a binds death receptor-6 to induce THP-1 monocytes differentiation via NF-κB pathway

Analyses of apoptotic cell supernatants have helped identify many signals that modulate the states of activation and differentiation in the congeneric or other cells. However, the current knowledge about these soluble factors that are released during apoptosis is rather limited. Previous studies have shown that S5a/Angiocidin induced human acute monocytic leukemia cells (THP-1 cells) to differentiation into macrophages, but the cell surface receptor of S5a has not been identified. In this study we show that apoptotic THP-1 cells released endogenous S5a, and S5a bound with death receptor-6, which was identified as an orphan receptor, to induce THP-1 cells differentiation. Furthermore, we found NF-κB pathway was activated and the transcription factor WT1 and c-myb mediated THP-1 differentiation induced by S5a. And we also show that the differentiation was blocked after anti-DR6 antibody, DR6 siRNA, DR6-Fc, NF-κB inhibitor, or WT1 siRNA treatment. Our finding indicated that the interaction between cells can determine their destination. And we provided evidence for a functional interaction between S5a and DR6, which provides a novel target that can induce the differentiation of cancer cells especially for biotherapy of leukemia.

Immunolocalization of Wilms' Tumor protein (WT1) in developing human peripheral sympathetic and gastroenteric nervous system

Developmental expression of Wilms' tumor gene (WT1) and protein is crucial for cell proliferation, apoptosis, differentiation and cytoskeletal architecture regulation. Recently, a potential role of WT1 has been suggested in the development of neural tissue and in neurodegenerative disorders. We have investigated immunohistochemically the developmentally regulated expression and distribution of WT1 in the human fetal peripheral sympathetic nervous system (PSNS) and the gastro-enteric nervous system (GENS) from weeks 8 to 28 gestational age. WT1 expression was restricted to the cytoplasm of sympathetic neuroblasts, while it progressively disappeared with advancing morphologic differentiation of these cells along both ganglionic and chromaffin cell lineages. In adult tissues, both ganglion and chromaffin cells lacked any WT1 expression. These findings show that WT1 is a reliable marker of human sympathetic neuroblasts, which can be used routinely in formalin-fixed, paraffin-embedded tissues. The progressive loss of WT1 in both ganglion and chromaffin cells, suggests its potential repressor role of differentiation in a precise temporal window during the development of the human PSNS and GENS.