CMIP interacts with WT1 and targets it on the proteasome degradation pathway

BACKGROUND

The Wilms tumor 1 suppressor gene, WT1, is expressed throughout life in podocytes and is essential for their function. Downregulation of WT1 has been reported in podocyte diseases but the underlying mechanisms remain unclear. Podocyte injury is the hallmark of idiopathic nephrotic syndrome (INS), the most frequent glomerular disease in children and young adults. An increase in the abundance of Cmaf-inducing protein (CMIP) has been found to alter podocyte function, but it is not known whether CMIP affects WT1 expression.

METHODS

Transcriptional and post-transcriptional regulation of WT1in the presence of CMIP was studied using transient transfection, mouse models, and siRNA handling.

RESULTS

We showed that overproduction of CMIP in the podocyte was consistently associated with a downregulation of WT1 according to two mechanisms. We found that CMIP prevented the NF-kB-mediated transcriptional activation of WT1. We demonstrated that CMIP interacts directly with WT1 through its leucine-rich repeat domain. Overexpression of CMIP in the M15 cell line induced a downregulation of WT1, which was prevented by lactacystin, a potent proteasome inhibitor. We showed that CMIP exhibits an E3 ligase activity and targets WT1 to proteasome degradation. Intravenous injection of Cmip-siRNA specifically prevented the repression of Wt1 in lipopolysaccharides-induced proteinuria in mice.

CONCLUSIONS

These data suggest that CMIP is a repressor of WT1 and might be a critical player in the pathophysiology of some podocyte diseases. Because WT1 is required for podocyte integrity, CMIP could be considered a therapeutic target in podocyte diseases.

Distinct difference in tumor-infiltrating immune cells between Wilms' tumor gene 1 peptide vaccine and anti-programmed cell death-1 antibody therapies

Background

Wilms’ tumor gene 1 (WT1) peptide vaccine and anti-programmed cell death-1 (anti-PD-1) antibody are expected as immunotherapies to improve the clinical outcome of glioblastoma. The aims of this study were to clarify how each immunotherapy affects tumor-infiltrating immune cells (TIIs) and to determine whether the combination of these two therapies could synergistically work.

Methods

Mice were transplanted with WT1 and programmed cell death-ligand 1 doubly expressing glioblastoma cells into brain followed by treatment with WT1 peptide vaccine, anti-PD-1 antibody, or the combination of the two, and survival of each therapy was compared. CD45⁺ cells were positively selected as TIIs from the brains with tumors, and TIIs were compared between WT1 peptide vaccine and anti-PD-1 antibody therapies.

Results

Most mice seemed to be cured by the combination therapy with WT1 peptide vaccine and anti-PD-1 antibody, which was much better survival than each monotherapy. A large number of CD4⁺ T cells, CD8⁺ T cells, and NK cells including WT1-specific CD8⁺ and CD4⁺ T cells infiltrated into the glioblastoma in WT1 peptide vaccine-treated mice. On the other hand, the number of TIIs did not increase, but instead PD-1 molecule expression was decreased on the majority of the tumor-infiltrating CD8⁺ T cells in the anti-PD-1 antibody-treated mice.

Conclusion

Our results clearly demonstrated that WT1 peptide vaccine and anti-PD-1 antibody therapies worked in the different steps of cancer-immunity cycle and that the combination of the two therapies could work synergistically against glioblastoma.

A Novel HAGE/WT1-ImmunoBody® Vaccine Combination Enhances Anti-Tumour Responses When Compared to Either Vaccine Alone

Many cancers, including myeloid leukaemia express the cancer testis antigen (CTA) DDX43 (HAGE) and/or the oncogene Wilms’ tumour (WT1). Here we demonstrate that HAGE/WT1-ImmunoBody^® vaccines derived T-cells can kill ex-vivo human CML cell lines expressing these antigens and significantly delay B16/HHDII⁺/DR1⁺/HAGE⁺/WT1⁺ tumour growth in the HHDII/DR1 mice and prolonged mouse survival in the prophylactic setting in comparison to non-immunised control mice. We show that immunisation of HHDII/DR1 mice with HAGE- and WT1-ImmunoBody^® DNA vaccines in a prime-boost regime in two different flanks induce significant IFN-γ release by splenocytes from treated mice, and a significant level of cytotoxicity against tumour targets expressing HAGE/WT1 in vitro. More importantly, the combined HAGE/WT1 ImmunoBody^® vaccine significantly delayed tumour growth in the B16/HHDII⁺/DR1⁺/HAGE⁺/WT1⁺ tumour model and prolonged mouse survival in the prophylactic setting in comparison to non-immunised control mice. Overall, this work demonstrates that combining both HAGE- and WT1-ImmunoBody^® into a single vaccine is better than either vaccine alone. This combination vaccine could be given to patients whose cancer expresses HAGE and WT1 in parallel with existing therapies in order to decrease the chance of disease progression and relapse.

The Expression of Transcription Factors in Fetal Lamb Kidney

(1) Background: Renal development involves frequent expression and loss of transcription factors, resulting in the activation of genes. Wilms’ tumor 1 (WT1), hepatocyte nuclear factor-1-beta (HNF1β), and paired box genes 2 and 8 (Pax2 and Pax8) play an important role in renal development. With this in vivo study, we examined the period and location of expression of these factors in renal development. (2) Methods: Fetal lamb kidneys (50 days from gestation to term) and adult ewe kidneys were evaluated by hematoxylin and eosin staining. Serial sections were subjected to immunohistochemistry for WT1, HNF1β, Pax2, and Pax8. (3) Results: Pax2, Pax8, and HNF1β expression was observed in the ureteric bud and collecting duct epithelial cells. We observed expression of WT1 alone in metanephric mesenchymal cells, glomerular epithelial cells, and interstitial cells in the medullary rays and Pax8 and HNF1β expression in tubular epithelial cells. WT1 was highly expressed in cells more proximal to the medulla in renal vesicles and in C- and S-shaped bodies. Pax2 was expressed in the middle and peripheral regions, and HNF1β in cells in the region in the middle of these. (4) Conclusions: WT1 is involved in nephron development. Pax2, Pax8, and HNF1β are involved in nephron maturation and the formation of peripheral collecting ducts from the Wolffian duct.

Novel combined variants of WT1 and TET2 in a refractory and recurrent AML patient

BACKGROUND

Somatic mutations in Wilms' tumor 1 (WT1) and tet methylcytosine dioxygenase 2 (TET2) genes were separately perceived as contributors to hematopoietic disorders and usually thought to have a mutually exclusive effect in acute myeloid leukemia (AML). However, we found novel WT1 and TET2 variants persistently co-existed in a refractory and recurrent AML patient with t(9;11)(p21.3;q23.3); KMT2A-MLLT3, and were only detectable genetic alteration in early recurrence. Hence, these two novel variants were further investigated in patient's family, and the potential effect on disease progression was evaluated at follow-up.

CASE PRESENTATION

A 27-year-old male was diagnosed with AML, having t(9;11)(p21.3;q23.3); KMT2A-MLLT3, accompanied by WT1 (NM_024426.6:exon7:c.1109G>C:p.Arg370Pro) and TET2 (NM_001127208.3:exon11:c.5530G>A:p.Asp1844Asn) variants. After two cycles of induction chemotherapy, complete remission was achieved. A consolidation treatment was then completed. However, the evaluation of the bone marrow revealed that early recurrence, WT1 (p.Arg370Pro) and TET2 (p.Asp1844Asn) variants still detectable, instead of KMT2A-MLLT3. Subsequently, these two variants were proved to be germline variants, which inherited from father and mother respectively. And the patient's elder brother also carried TET2 (p.Asp1844Asn) variant. A sequential allogeneic HLA-matched sible hematopoietic stem cell transplantation (allo-HSCT) was carried out, and the donor is the patient's elder brother, the original two variants of patient were replaced by the donor-derived TET2 (p.Asp1844Asn) variant after allo-HSCT; the patient has remained in complete remission with regular follow-up.

CONCLUSIONS

In brief, it is firstly reported that WT1 p.Arg370Pro and TET2 p.Asp1844Asn variants co-existed in a refractory and recurrent AML patient by inheritance. These two variants of the patient were replaced with donor-derived TET2 p.Asp1844Asn after allo-HSCT, and the patient has remained in complete remission with regular follow-up.

Overexpression of Wilms tumor 1 promotes IL-1β expression by upregulating histone acetylation in keratinocytes

Psoriasis is a common inflammatory skin disease. Infiltration of inflammatory cells and excessive proliferation of keratinocytes are the histopathological markers of psoriasis. The transcription factor Wilms Tumor 1 (WT1) is overexpressed in several tumor types, and plays an important part in the proliferation and apoptosis of cells. Studies have found that, compared with normal skin, WT1expression in the skin lesions of patients with psoriasis are increased significantly. Knockdown of WT1 inhibited the proliferation of a human epidermal keratinocyte cell line (HaCaT cells) and promoted their apoptosis, whereas WT1 overexpression exhibited the opposite effect. WT1 was overexpressed or inhibited in HaCaT cells by transfection with the WT1 plasmid or WT1 small interferring RNA (siRNA) using Lipofectamine 2000. Transcriptome sequencing and bioinformatics analysis revealed significant differences in IL-1β expression between the experimental group and control group. Real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assays showed that expression of IL-1β and WT1 were consistent. Subsequently, IL-1β was demonstrated to be a target of WT1 by chromatin immunoprecipitation (ChIP)-sequencing and luciferase reporter assay. ChIP-qPCR showed that WT1 regulated IL-1β expression by altering acetylation. Expression of WT1 mRNA was positively correlated with expression of IL-1β mRNA in psoriatic skin lesions. Our study suggested that WT1 likely promotes psoriasis development by regulating its target gene IL-1β, which shows high expression in psoriatic lesions and is involved in psoriasis development. These findings provide a new target for psoriasis treatment.

Prognostic impact of pretransplant measurable residual disease assessed by peripheral blood WT1-mRNA expression in patients with AML and MDS

OBJECTIVE

As peripheral blood (PB) Wilm's Tumor 1 (WT1)-mRNA expression is established as MRD-marker during conventional AML chemotherapy, impact of pretransplant WT1 expression remains unclear. Therefore, we aimed to assess prognostic impact of pretransplant WT1 expression on post-transplant outcome in patients with AML/MDS.

METHODS

In 64 AML/MDS patients, pretransplant WT1 expression was retrospectively analyzed using a standardized assay offering high sensitivity, specificity, and a validated cut-off. Patients were divided into three groups determined by pretransplant remission and WT1 expression. Post-transplant outcome of these groups was compared regarding cumulative incidence of relapse (CIR), relapse-free (RFS), and overall survival (OS).

RESULTS

Pretransplant forty-six patients (72%) showed hematologic remission, including 21 (46%) MRD-negative and 25 (54%) MRD-positive patients indicated by WT1 expression, while 18 refractory patients (28%) showed active disease. Two-year estimates of post-transplant CIR, RFS, and OS were similar in MRD-positive (61%, 37%, 54%) and refractory patients (70%, 26%, 56%), but significantly inferior compared with MRD-negative patients (10%, 89%, 90%). After multivariable adjustment, pretransplant MRD negativity measured by WT1 expression retained its prognostic impact on CIR (P = .008), RFS (P = .005), and OS (P = .049).

CONCLUSIONS

PB WT1 expression represents a useful method to estimate pretransplant MRD, which is highly predictable for post-transplant outcome and may help improving peri-transplant management in AML/MDS patients.

Genotype-Phenotype Correlation in WT1 Exon 8 to 9 Missense Variants

Introduction

WT1 missense mutation in exon 8 or 9 causes infantile nephrotic syndrome with early progression to end-stage kidney disease (ESKD), Wilms tumor, and 46,XY female. However, some patients with missense mutations in exon 8 or 9 progress to ESKD in their teens or later. Therefore, we conducted a systematic review and functional analysis of WT1 transcriptional activity.

Methods

We conducted a systematic review of 174 cases with WT1 exon 8 or 9 missense variants from our cohort (n=13) and previous reports (n=161). Of these cases, mild and severe genotypes were selected for further in vitro functional analysis using luciferase assay.

Results

The median age of developing ESKD was 1.17 years. A comparative study was conducted among three WT1 genotype classes: mutations of the DNA-binding site (DBS group), mutations outside the DNA-binding site but at sites important for zinc finger structure formation by 2 cysteines and 2 histidines (C2H2 group), and mutations leading to other amino acid changes (Others group). The DBS group showed the severest phenotype and the C2H2 group was intermediate, whereas the Others group showed the mildest phenotype (developing ESKD at 0.90, 2.00, and 3.92 years, respectively, with significant differences). In vitro functional analysis showed dominant-negative effects for all variants; in addition, the DBS and C2H2 mutations were associated with significantly lower WT1 transcriptional activity than the other mutations.

Conclusion

Not only the DNA-binding site but also C2H2 zinc finger structure sites are important for maintaining WT1 transcriptional activity, and their mutation causes severe clinical symptoms.

Defective mesothelium and limited physical space are drivers of dysregulated lung development in a genetic model of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a developmental disorder associated with diaphragm defects and lung hypoplasia. The etiology of CDH is complex and its clinical presentation is variable. We investigated the role of the pulmonary mesothelium in dysregulated lung growth noted in the Wt1 knockout mouse model of CDH. Loss of WT1 leads to intrafetal effusions, altered lung growth, and branching defects prior to normal closure of the diaphragm. We found significant differences in key genes; however, when Wt1 null lungs were cultured ex vivo, growth and branching were indistinguishable from wild-type littermates. Micro-CT imaging of embryos in situ within the uterus revealed a near absence of space in the dorsal chest cavity, but no difference in total chest cavity volume in Wt1 null embryos, indicating a redistribution of pleural space. The altered space and normal ex vivo growth suggest that physical constraints are contributing to the CDH lung phenotype observed in this mouse model. These studies emphasize the importance of examining the mesothelium and chest cavity as a whole, rather than focusing on single organs in isolation to understand early CDH etiology.

Dendritic cell vaccination combined with a conventional chemotherapy for patients with relapsed or advanced pancreatic ductal adenocarcinoma: a single-center phase I/II trial

The prognosis of patients with advanced pancreatic cancer is poor. In the present phase I/II study, we have evaluated the safety and the feasibility of Wilms' tumor 1 (WT1) and/or mucin1 (MUC1) peptide-pulsed dendritic cell (DC) vaccination in combination with chemotherapy in patients with advanced or relapsed pancreatic ductal adenocarcinoma (PDAC). Sixty-five eligible patients were enrolled. No severe adverse events related to the vaccinations were observed. Objective response rate and disease control rate was 12.3% and 50.8%, respectively. Median progression-free survival and overall survival were 4.9 and 9.6 months, respectively. DC vaccinations augmented WT1- and MUC1-specific immunity which might be related to clinical outcome. These results indicate that DC-based immunotherapy combined with a conventional chemotherapy is safe and feasible for patients in advanced stage of PDAC.

Immunohistochemical characterization of mesothelioma in 6 large felids

Mesothelioma has been reported frequently in large felids. These neoplasms present a diagnostic challenge given their highly variable morphology that mimics carcinomas or sarcomas at different locations. Our goal was to characterize mesotheliomas morphologically and immunohistochemically to determine if a panel of antibodies could be used to more accurately support the diagnosis of these neoplasms in large felids. Mesotheliomas from 6 large felids, including 4 clouded leopards, 1 Bengal tiger, and 1 cheetah, were immunohistochemically labeled for vimentin, E-cadherin, pancytokeratin, Wilms tumor 1 (WT1), MUC-1, and calretinin. The mesotheliomas of the 4 clouded leopards and the tiger were of the epithelial subtype; the mesothelioma from the cheetah was biphasic. All 6 mesotheliomas had strong immunohistochemical labeling for vimentin, E-cadherin, and pancytokeratin. All cases had cytoplasmic labeling for WT1, and 2 also had nuclear labeling. The 3 mesotheliomas with distinct papillary fronds were weakly positive for MUC-1. These and one other epithelial mesothelioma were also positive for calretinin. Our study demonstrates that the morphologic and immunohistochemical phenotypes of mesothelioma that have been identified in humans and domestic species can occur in large felids, and a panel of pancytokeratin, vimentin, WT1, and calretinin can be utilized to support the diagnosis of these neoplasms.

The extracellular matrix protein agrin is essential for epicardial epithelial-to-mesenchymal transition during heart development

During heart development, epicardial cells residing within the outer layer undergo epithelial-mesenchymal transition (EMT) and migrate into the underlying myocardium to support organ growth and morphogenesis. Disruption of epicardial EMT results in embryonic lethality, yet its regulation is poorly understood. Here, we report epicardial EMT within the mesothelial layer of the mouse embryonic heart at ultra-high resolution using scanning electron microscopy combined with immunofluorescence analyses. We identified morphologically active EMT regions that associated with key components of the extracellular matrix, including the basement membrane-associated proteoglycan agrin. Deletion of agrin resulted in impaired EMT and compromised development of the epicardium, accompanied by downregulation of Wilms' tumor 1. Agrin enhanced EMT in human embryonic stem cell-derived epicardial-like cells by decreasing β-catenin and promoting pFAK localization at focal adhesions, and promoted the aggregation of dystroglycan within the Golgi apparatus in murine epicardial cells. Loss of agrin resulted in dispersal of dystroglycan in vivo, disrupting basement membrane integrity and impairing EMT. Our results provide new insights into the role of the extracellular matrix in heart development and implicate agrin as a crucial regulator of epicardial EMT.

Comprehensive analysis based on DNA methylation and RNA-seq reveals hypermethylation of the up-regulated WT1 gene with potential mechanisms in PAM50 subtypes of breast cancer

Background

Breast cancer (BC), one of the most widespread cancers worldwide, caused the deaths of more than 600,000 women in 2018, accounting for about 15% of all cancer-associated deaths in women that year. In this study, we aimed to discover potential prognostic biomarkers and explore their molecular mechanisms in different BC subtypes using DNA methylation and RNA-seq.

Methods

We downloaded the DNA methylation datasets and the RNA expression profiles of primary tissues of the four BC molecular subtypes (luminal A, luminal B, basal-like, and HER2-enriched), as well as the survival information from The Cancer Genome Atlas (TCGA). The highly expressed and hypermethylated genes across all the four subtypes were screened. We examined the methylation sites and the downstream co-expressed genes of the selected genes and validated their prognostic value using a different dataset (GSE20685). For selected transcription factors, the downstream genes were predicted based on the Gene Transcription Regulation Database (GTRD). The tumor microenvironment was also evaluated based on the TCGA dataset.

Results

We found that Wilms tumor gene 1 (WT1), a transcription factor, was highly expressed and hypermethylated in all the four BC subtypes. All the WT1 methylation sites exhibited hypermethylation. The methylation levels of the TSS200 and 1stExon regions were negatively correlated with WT1 expression in two BC subtypes, while that of the gene body region was positively associated with WT1 expression in three BC subtypes. Patients with low WT1 expression had better overall survival (OS). Five genes including COL11A1, GFAP, FGF5, CD300LG, and IGFL2 were predicted as the downstream genes of WT1. Those five genes were dysregulated in the four BC subtypes. Patients with a favorable 6-gene signature (low expression of WT1 and its five predicted downstream genes) exhibited better OS than that with an unfavorable 6-gene signature. We also found a correlation between WT1 and tamoxifen using STITCH. Higher infiltration rates of CD8 T cells, plasma cells, and monocytes were found in the lower quartile WT1 group and the favorable 6-gene signature group. In conclusion, we demonstrated that WT1 is hypermethylated and up-regulated in the four BC molecular subtypes and a 6-gene signature may predict BC prognosis.

Induced dendritic cells co-expressing GM-CSF/IFN-α/tWT1 priming T and B cells and automated manufacturing to boost GvL

Acute myeloid leukemia (AML) patients with minimal residual disease and receiving allogeneic hematopoietic stem cell transplantation (HCT) have poor survival. Adoptive administration of dendritic cells (DCs) presenting the Wilms tumor protein 1 (WT1) leukemia-associated antigen can potentially stimulate de novo T and B cell development to harness the graft-versus-leukemia (GvL) effect after HCT. We established a simple and fast genetic modification of monocytes for simultaneous lentiviral expression of a truncated WT1 antigen (tWT1), granulocyte macrophage-colony-stimulating factor (GM-CSF), and interferon (IFN)-α, promoting their self-differentiation into potent “induced DCs” (iDCtWT1). A tricistronic integrase-defective lentiviral vector produced under good manufacturing practice (GMP)-like conditions was validated. Transduction of CD14⁺ monocytes isolated from peripheral blood, cord blood, and leukapheresis material effectively induced their self-differentiation. CD34⁺ cell-transplanted Nod.Rag.Gamma (NRG)- and Nod.Scid.Gamma (NSG) mice expressing human leukocyte antigen (HLA)-A∗0201 (NSG-A2)-immunodeficient mice were immunized with autologous iDCtWT1. Both humanized mouse models showed improved development and maturation of human T and B cells in the absence of adverse effects. Toward clinical use, manufacturing of iDCtWT1 was up scaled and streamlined using the automated CliniMACS Prodigy system. Proof-of-concept clinical-scale runs were feasible, and the 38-h process enabled standardized production and high recovery of a cryopreserved cell product with the expected identity characteristics. These results advocate for clinical trials testing iDCtWT1 to boost GvL and eradicate leukemia.

MicroRNA-216a targets WT1 expression and regulates KRT7 transcription to mediate the progression of pancreatic cancer-A transcriptome analysis

Gene expression profiling has been broadly performed in the field of cancer research. This study aims to explore the key gene regulatory network and focuses on the functions of microRNA (miR)-216a in pancreatic cancer (PC). PC datasets GSE15471, GSE16515, and GSE32676 were used to screen the differentially expressed genes (DEGs) in PC. A miRNA microarray analysis and gene oncology analysis suggested miR-216a as an important differentially expressed miRNA in PC. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that miR-216a and the DEGs are largely enriched on the phosphatidyl inositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. miR-216a targeted Wilms Tumor 1 (WT1), while WT1 promoted transcription activity of keratin 7 (KRT7). Upregulation of miR-216a reduced proliferation and invasiveness of PC cells, while further upregulation of WT1 blocked the functions of miR-216a. Silencing of KRT7 diminished the oncogenic role of WT1. The in vitro results were reproduced in vivo. High expression of miR-216a while poor expression of WT1 indicated better prognosis of PC patients. The miR-216a/WT1/KRT7 axis influenced the activity of the PI3K/AKT pathway. To conclude, this study evidenced that miR-216a suppressed WT1 expression and blocked KRT7 transcription, which inactivated the PI3K/AKT signaling and reduced PC progression.

Focal Segmental Membranoproliferative Glomerulonephritis: A Histological Variant of Denys-Drash Syndrome

Introduction: Denys-Drash Syndrome (DDS) consists of a triad of pseudohermaphroditism, Wilms'tumor and nephropathy. This condition may manifest as a complete triad or in an incomplete form; with either one or a combination of the above features. The characteristic glomerular abnormality in DDS is diffuse mesangial sclerosis (DMS).Case report: We report two cases of DDS with focal membranoproliferative glomerulonephritis (MPGN). Both of our cases were males with ambiguous genitalia. They had a similar heterozygous germline mutation in exon 9 of WT1, c.1180C>T, p.R394W; a known mutation hotspot for DDS. Case 1 had nephropathy at the age of 4 years and Case 2 at 2.5 years with different rates of progression to end-stage renal failure. Conclusion: Our findings, in combination with other reports, illustrate the clinicopathological heterogeneity of DDS. There are no universal recommendations for optimal management of patients with DDS due to the inability to accurately predict affected individuals' progress.

High-Dose Vitamin C: Preclinical Evidence for Tailoring Treatment in Cancer Patients

Simple Summary

Vitamin C is an indispensable micronutrient in the human diet due to the multiple functions it carries out in the body. Reports of clinical studies have indicated that, when administered at high dosage by the intravenous route, vitamin C may exert beneficial antitumor effects in patients with advanced stage cancers, including those refractory to previous treatment with chemotherapy. The aim of this article is to provide an overview of the current scientific evidence concerning the different mechanisms of action by which high-dose vitamin C may kill tumor cells. A special focus will be given to those mechanisms that provide the rationale basis for tailoring vitamin C treatment according to specific molecular alterations present in the tumor and for the selection of the most appropriate companion drugs.

Abstract

High-dose vitamin C has been proposed as a potential therapeutic approach for patients with advanced tumors who failed previous treatment with chemotherapy. Due to vitamin C complex pharmacokinetics, only intravenous administration allows reaching sufficiently high plasma concentrations required for most of the antitumor effects observed in preclinical studies (>0.250 mM). Moreover, vitamin C entry into cells is tightly regulated by SVCT and GLUT transporters, and is cell type-dependent. Importantly, besides its well-recognized pro-oxidant effects, vitamin C modulates TET enzymes promoting DNA demethylation and acts as cofactor of HIF hydroxylases, whose activity is required for HIF-1α proteasomal degradation. Furthermore, at pharmacological concentrations lower than those required for its pro-oxidant activity (<1 mM), vitamin C in specific genetic contexts may alter the DNA damage response by increasing 5-hydroxymethylcytosine levels. These more recently described vitamin C mechanisms offer new treatment opportunities for tumors with specific molecular defects (e.g., HIF-1α over-expression or TET2, IDH1/2, and WT1 alterations). Moreover, vitamin C action at DNA levels may provide the rationale basis for combination therapies with PARP inhibitors and hypomethylating agents. This review outlines the pharmacokinetic and pharmacodynamic properties of vitamin C to be taken into account in designing clinical studies that evaluate its potential use as anticancer agent.

The miR-203a Regulatory Network Affects the Proliferation of Chronic Myeloid Leukemia K562 Cells

To study the molecular mechanism by which miR-203a affects the development of CML, bioinformatics software was used to predict the upstream transcription factors and downstream target genes of miR-203a. A 5’-rapid amplification of cDNA ends assay was performed to detect gene transcription initiation sites. A chromatin immunoprecipitation assay was used to verify the binding of transcription factors and promoter regions. A double luciferase reporter gene vector was constructed to demonstrate the regulatory effect of miR-203a on target genes. Real-time PCR and western blotting were used to detect the relative expression levels of genes and proteins, respectively. The results showed that there was a binding site for the transcription factor EGR1 in the upstream promoter region of miR-203a. WT1, BMI1, and XIAP were identified as target genes regulated by miR-203a. EGR1 and miR-203a were downregulated in human peripheral blood mononuclear cells and the CML K562 cell line, while WT1, BMI1, and XIAP were upregulated. The transcription initiation site of miR-203a was identified in the upstream promoter region (G nucleotide at −339 bp), and the transcription factor EGR1 could bind to the promoter region (at −268 bp) of miR-203a and increase its expression. Over expression of miR-203a inhibited the proliferation of K562 cells. A rescue assay showed that overexpression of WT1, BMI1, and XIAP offset the antitumor effect of miR-203a. Conclusion, EGR1 positively regulated the expression of miR-203a, thus relieving the inhibition of miR-203a on the translation of its target genes (WT1, BMI1, and XIAP) and affecting the proliferation of K562 cells.

[CASC5</I> Gene Expression Changes Correlate with Targeted Mutations in Leukemia]

Dysfunction of genes that control mitosis and are responsible for the correct segregation of sister chromatids in anaphase is often accompanied by aneuploidy, which is frequently detected in leukemia. One of the components of the kinetochore complex, namely, the AF15q14/KNL1/CASC5 protein, is an important factor ensuring the correct binding of the pericentromeric region of chromosomes with the spindle microtubules. As shown recently, in some leukemias, the gene of this protein can be involved in the generation of the chromosomal translocation t(11;15)(q23;q14) or a variant of the chimeric MLL-AF15Q14 oncogene, which serves as a biomarker of poor prognosis. Despite the implication of mRNA of the CASC5 gene in oncogenesis of solid tumors, expression of this gene in hematopoietic neoplasms has not been studied. We analyzed expression levels of the CASC5 gene and the nearest regulatory genes, including WT1, APOBEC3A (A3A), and N-MYC. A pronounced decrease in CASC5 expression in bone marrow cells of primary leukemia patients compared with healthy donors was found. It was also shown that reduced expression of the CASC5 gene correlates with the detection of targeted mutations in patients composed two prognostic subgroups (favorable, unfavorable) with a significance level (p <0.05). It was noted that the change in the expression level of the CASC5 gene in acute myeloid leukemia is associated with overexpression of the genes WT1, A3A, and in some cases N-MYC and SPT16, which is consistent with the resistance to chemotherapy and leukemia progression. However, the question of which regulatory gene initiates leukemogenesis remains open.

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.

Correlation of miR-600 with WT1 expression and its potential clinical significance in breast cancer

Aim: The study aimed to explore miR-600 and WT1 expression and its potential clinical significance in breast cancer. Materials & methods: The expression of miR-600 and WT1 in tumor and non-tumor adjacent tissues in 45 breast cancer patients as well as serum level of miR-600 in these patients and 45 healthy group were analyzed. Results: The expression level of miR-600 in tumor tissue and serum of patients was significantly lower than non-tumor adjacent tissues and serum of controls, respectively, while WT1 mRNA and protein levels were higher in tumor tissues compared with non-tumor adjacent tissues. The miR-600 expression was correlated with lymph node metastasis and clinical stage. Conclusion: The miR-600 acts as tumor suppressor and a diagnostic and prognostic biomarker in breast cancer patients.

Prognostic impact of peripheral blood Wilms' tumour 1 mRNA expression levels in response to azacytidine in MDS: A single-centre analysis

To determine the impact of peripheral blood (PB) Wilms' tumour 1 (WT-1) mRNA levels in patients with primary myelodysplastic syndromes (MDS), we analysed the relationships between several clinical variables at the time of diagnosis and the haematological response of patients treated with azacytidine. We observed overall responses in 20 (63%) patients; there were no significant differences in clinical variables, including bone marrow blast counts, IPSS scores and IPSS-R risk scores, between responders and non-responders. The responders' PB WT-1 mRNA levels were significantly lower than those of non-responders (P = 0.03). PB WT-1 mRNA expression could be a marker for predicting the response to azacytidine in patients with de novo MDS.

Epigenomic Reprogramming toward Mesenchymal-Epithelial Transition in Ovarian-Cancer-Associated Mesenchymal Stem Cells Drives Metastasis

A role for cancer cell epithelial-to-mesenchymal transition (EMT) in cancer is well established. Here, we show that, in addition to cancer cell EMT, ovarian cancer cell metastasis relies on an epigenomic mesenchymal-to-epithelial transition (MET) in host mesenchymal stem cells (MSCs). These reprogrammed MSCs, termed carcinoma-associated MSCs (CA-MSCs), acquire pro-tumorigenic functions and directly bind cancer cells to serve as a metastatic driver/chaperone. Cancer cells induce this epigenomic MET characterized by enhancer-enriched DNA hypermethylation, altered chromatin accessibility, and differential histone modifications. This phenomenon appears clinically relevant, as CA-MSC MET is highly correlated with patient survival. Mechanistically, mirroring MET observed in development, MET in CA-MSCs is mediated by WT1 and EZH2. Importantly, EZH2 inhibitors, which are clinically available, significantly inhibited CA-MSC-mediated metastasis in mouse models of ovarian cancer.

Effect of lncRNA WT1-AS regulating WT1 on oxidative stress injury and apoptosis of neurons in Alzheimer's disease via inhibition of the miR-375/SIX4 axis

Objective: To study the effect of lncRNA WT1-AS on oxidative stress injury (OSI) and apoptosis of neurons in Alzheimer's disease (AD) and its specific mechanisms related to the microRNA-375 (miR-375)/SIX4 axis and WT1 expression.

Results: After bioinformatic prediction, WT1-AS was found to be downregulated in Aβ_25-35treated SH-SY5Y cells, and WT1-AS overexpression inhibited WT1 expression. WT1 could target miR-375 to promote its expression. miR-375 bound to SIX4, and miR-375 overexpression inhibited SIX4 expression. WT1-AS inhibited OSI and apoptosis, while WT1 and miR-375 overexpression or SIX4 silencing reversed the WT1-AS effect on OSI and apoptosis. In vivo experiments revealed that WT1-AS improved learning/memory abilities and inhibited OSI and apoptosis in AD mice.

Conclusion: Overexpression of WT1-AS can inhibit the miR-375/SIX4 axis, OSI and neuronal apoptosis in AD by inhibiting WT1 expression.

Methods: Related lncRNAs were identified, and miR-375 downstream targets were predicted. WT1-AS, WT1, miR-375 and SIX4 expression was detected in a cell model induced by Aβ_25-35. The binding of WT1 with miR-375 and that of miR-375 with SIX4 were further confirmed. Adenosine triphosphate (ATP), reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and lactate dehydrogenase (LDH) activities, and apoptosis levels were tested after mitochondrial membrane potential observation. Learning/memory abilities and neuronal apoptosis were tested in a mouse model.

The spectrum of rare central nervous system (CNS) tumors with EWSR1-non-ETS fusions: experience from three pediatric institutions with review of the literature

The group of CNS mesenchymal (non‐meningothelial) and primary glial/neuronal tumors in association with EWSR1‐non‐ETS rearrangements comprises a growing spectrum of entities, mostly reported in isolation with incomplete molecular profiling. Archival files from three pediatric institutions were queried for unusual cases of pediatric (≤21 years) CNS EWSR1‐rearranged tumors confirmed by at least one molecular technique. Extra‐axial tumors and cases with a diagnosis of Ewing sarcoma (EWSR1‐ETS family fusions) were excluded. Additional studies, including anchored multiplex‐PCR with next‐generation sequencing and DNA methylation profiling, were performed as needed to determine fusion partner status and brain tumor methylation class, respectively. Five cases (median 17 years) were identified (M:F of 3:2). Location was parenchymal (n = 3) and undetermined (n = 2) with topographic distributions including posterior fossa (n = 1), frontal (n = 1), temporal (n = 1), parietal (n = 1) and occipital (n = 1) lobes. Final designation with fusion findings included desmoplastic small round cell tumor (EWSR1‐WT1; n = 1) and tumors of uncertain histogenesis (EWSR1‐CREM, n = 1; EWSR1‐CREB1, n = 1; EWSR1‐PLAGL1, n = 1; and EWSR1‐PATZ1, n = 1). Tumors showed a wide spectrum of morphology and biologic behavior. For EWSR1‐CREM, EWSR1‐PLAGL1 and EWSR1‐PATZ1 tumors, no significant methylation scores were reached in the known brain tumor classes. Available outcome (4/5) was reported as favorable (n = 2) and unfavorable (n = 2) with a median follow‐up of 30 months. In conclusion, we describe five primary EWSR1‐non‐ETS fused CNS tumors exhibiting morphologic and biologic heterogeneity and we highlight the clinical importance of determining specific fusion partners to improve diagnostic accuracy, treatment and monitoring. Larger prospective clinicopathological and molecular studies are needed to determine the prognostic implications of histotypes, anatomical location, fusion partners, breakpoints and methylation profiles in patients with these rare tumors.