An internal deletion within an 11p13 zinc finger gene contributes to the development of Wilms' tumor

Overexpression of WT1 in all molecular subtypes of breast cancer and its impact on survival: exploring oncogenic and tumor suppressor roles of distinct WT1 isoforms

BACKGROUND

Breast cancer is a highly heterogeneous solid tumor, posing challenges in developing targeted therapies effective for all mammary carcinoma subtypes. WT1 emerges as a promising target for breast cancer therapy due to its potential oncogenic role in various cancer types. Previous works have yielded inconsistent results. Therefore, further studies are needed to clarify the behavior of this complex gene in breast cancer.

METHODS AND RESULTS

In this study, we examined WT1 expression in both Formalin Fixed Paraffin Embedded breast tumors (n = 41) and healthy adjacent tissues (n = 41) samples from newly diagnosed cases of ductal invasive breast cancer. The fold change in gene expression between the tumor and healthy tissue was determined by calculating 2-∆∆Ct. Disease-free survival analysis was computed using the Kaplan-Meier method. To identify the expression levels of different WT1 isoforms, we explored the ISOexpresso database. Relative quantification of the WT1 gene revealed an overexpression of WT1 in most cases. The percentage of patients surviving free of disease at 8 years of follow-up was lower in the group overexpressing WT1 compared to the group with down-regulated WT1.

CONCLUSIONS

Interestingly, this overexpression was observed in all molecular subtypes of invasive breast cancer, underscoring the significance of WT1 as a potential target in all these subtypes. The observed WT1 down-expression in a few cases of invasive breast cancer, associated with better survival outcomes, may correspond to the down-regulation of a particular WT1-KTS (-) isoform: the WT1 A isoform (EX5-/KTS-). The co-expression of this WT1 oncogenic isoform with a regulated WT1- tumor suppressor isoform, such as the major WT1 F isoform (EX5-/KTS +), could also explain such survival outcomes. Due to its capacity to adopt dual roles, it becomes imperative to conduct individual molecular expression profiling of the WT1 gene. Such an approach holds great promise in the development of personalized treatment strategies for breast cancer.

Wilms' tumor gene 1: lessons from the interface between kidney development and cancer

In 1990, mutations of the Wilms' tumor-1 gene (WT1), encoding a transcription factor in the embryonic kidney, were found in 10-15% of Wilms' tumors; germline WT1 mutations were associated with hereditary syndromes involving glomerular and reproductive tract dysplasia. For more than three decades, these discoveries prompted investigators to explore the embryonic role of WT1 and the mechanisms by which loss of WT1 leads to malignant transformation. Here, we discuss how alternative splicing of WT1 generates isoforms that act in a context-specific manner to activate or repress target gene transcription. WT1 also regulates posttranscriptional regulation, alters the epigenetic landscape, and activates miRNA expression. WT1 functions at multiple stages of kidney development, including the transition from resting stem cells to committed nephron progenitor, which it primes to respond to WNT9b signals from the ureteric bud. WT1 then drives nephrogenesis by activating WNT4 expression and directing the development of glomerular podocytes. We review the WT1 mutations that account for Denys-Drash syndrome, Frasier syndrome, and WAGR syndrome. Although the WT1 story began with Wilms' tumors, an understanding of the pathways that link aberrant kidney development to malignant transformation still has some important gaps. Loss of WT1 in nephrogenic rests may leave these premalignant clones with inadequate DNA repair enzymes and may disturb the epigenetic landscape. Yet none of these observations provide a complete picture of Wilms' tumor pathogenesis. It appears that the WT1 odyssey is unfinished and still holds a great deal of untilled ground to be explored.

Pregnancy-Associated Breast Cancer: A Diagnostic and Therapeutic Challenge

Pregnancy-associated breast cancer (PABC) is commonly defined as a breast cancer occurring during pregnancy, throughout 1 year postpartum, or during lactation. Despite being a rare circumstance, PABC is one of the most common types of malignancies occurring during pregnancy and lactation, with growing incidence in developed countries, due both to decreasing age at onset of breast cancer and to increasing maternal age. Diagnosis and management of malignancy in the prenatal and postnatal settings are challenging for practitioners, as the structural and functional changes that the breast undergoes may be misleading for both the radiologist and the clinician. Furthermore, safety concerns for the mother and child, as well as psychological aspects in this unique and delicate condition, need to be constantly considered. In this comprehensive review, clinical, diagnostic, and therapeutic aspects of PABC (including surgery, chemotherapy and other systemic treatments, and radiotherapy) are presented and fully discussed, based on medical literature, current international clinical guidelines, and systematic practice.

A Journey Through Genetics to Biology

Although my engagement with human genetics emerged gradually, and sometimes serendipitously, it has held me spellbound for decades. Without my teachers, students, postdocs, colleagues, and collaborators, I would not be writing this review of my scientific adventures. Early gene and disease mapping was a satisfying puzzle-solving exercise, but building biological insight was my main goal. The project trajectory was hugely influenced by the evolutionarily conserved nature of the implicated genes and by the pace of progress in genetic technologies. The rich detail of clinical observations, particularly in eye disease, makes humans an excellent model, especially when complemented by the use of multiple other animal species for experimental validation. The contributions of collaborators and rivals also influenced our approach. We are very fortunate to work in this era of unprecedented progress in genetics and genomics. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Whole exome sequencing identified a rare WT1 loss-of-function variant in a non-syndromic POI patient

BACKGROUND

Premature ovarian insufficiency (POI) is a highly heterogeneous disease, and up to 25% of cases can be explained by genetic causes. The transcription factor WT1 has long been reported to play a crucial role in ovary function. Wt1-mutated female mice exhibited POI-like phenotypes.

METHODS AND RESULTS

In this study, whole exome sequencing (WES) was applied to find the cause of POI in Han Chinese women. A nonsense variant in the WT1 gene: NM_024426.6:c.1387C>T(p.R463*) was identified in a non-syndromic POI woman. The variant is a heterozygous de novo mutation that is very rare in the human population. The son of the patient inherited the mutation and developed Wilms' tumor and urethral malformation at the age of 7. According to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, the novel variant is categorized as pathogenic. Western blot analysis further demonstrated that the WT1 variant could produce a truncated WT1 isoform in vitro.

CONCLUSIONS

A rare heterozygous nonsense WT1 mutant is associated with non-syndromic POI and Wilms' tumor. Our finding characterized another pathogenic WT1 variant, providing insight into genetic counseling.

METTL14 gene polymorphisms decrease Wilms tumor susceptibility in Chinese children

BACKGROUND

Wilms tumor is a highly heritable malignancy. Aberrant METTL14, a critical component of N6-methyladenosine (m⁶A) methyltransferase, is involved in carcinogenesis. The association between genetic variants in the METTL14 gene and Wilms tumor susceptibility remains to be fully elucidated. We aimed to assess whether variants within this gene are implicated in Wilms tumor susceptibility.

METHODS

A total of 403 patients and 1198 controls were analyzed. METTL14 genotypes were assessed by TaqMan genotyping assay.

RESULT

Among the five SNPs analyzed, rs1064034 T > A and rs298982 G > A exhibited a significant association with decreased susceptibility to Wilms tumor. Moreover, the joint analysis revealed that the combination of five protective genotypes exerted significantly more protective effects against Wilms tumor than 0-4 protective genotypes with an OR of 0.69. The stratified analysis further identified the protective effect of rs1064034 T > A, rs298982 G > A, and combined five protective genotypes in specific subgroups. The above significant associations were further validated by haplotype analysis and false-positive report probability analysis. Preliminary mechanism exploration indicated that rs1064034 T > A and rs298982 G > A are correlated with the expression and splicing event of their surrounding genes.

CONCLUSIONS

Collectively, our results suggest that METTL14 gene SNPs may be genetic modifiers for the development of Wilms tumor.

Recent advances in Wilms' tumor predisposition

Wilms' tumor (WT), the most common childhood kidney cancer, develops in association with an underlying germline predisposition in up to 15% of cases. Germline alterations affecting the WT1 gene and epigenetic alterations affecting the 11p15 locus are associated with a selective increase in WT risk. Nevertheless, WT also occurs in the context of more pleiotropic cancer predispositions, such as DICER1, Li-Fraumeni and Bloom syndrome, as well as Fanconi anemia. Recent germline genomic investigations have increased our understanding of the host genetic factors that influence WT risk, with sequencing of rare familial cases and large WT cohorts revealing an expanding array of predisposition genes and associated genetic conditions. Here, we describe evidence implicating WT1, the 11p15 locus, and the recently identified genes CTR9, REST and TRIM28 in WT predisposition. We discuss the clinical features, mode of inheritance and biological aspects of tumorigenesis, when known. Despite these described associations, many cases of familial WT remain unexplained. Continued investigations are needed to fully elucidate the landscape of germline genetic alterations in children with WT. Establishing a genetic diagnosis is imperative for WT families so that individuals harboring a predisposing germline variant can undergo surveillance, which should enable the early detection of tumors and use of less intensive treatments, thereby leading to improved overall outcomes.

Study of cellular heterogeneity and differential dynamics of autophagy in human embryonic kidney development by single-cell RNA sequencing

Background

Autophagy is believed to participate in embryonic development, but whether the expression of autophagy-associated genes undergoes changes during the development of human embryonic kidneys remains unknown.

Methods

In this work, we identified 36,151 human renal cells from embryonic kidneys of 9–18 gestational weeks in 16 major clusters by single-cell RNA sequencing (scRNA-seq), and detected 1350 autophagy-related genes in all fetal renal cells. The abundance of each cell cluster in Wilms tumor samples from scRNA-seq and GDC TARGET WT datasets was detected by CIBERSORTx. R package Monocle 3 was used to determine differentiation trajectories. Cyclone tool of R package scran was applied to calculate the cell cycle scores. R package SCENIC was used to investigate the transcriptional regulons. The FindMarkers tool from Seurat was used to calculate DEGs. GSVA was used to perform gene set enrichment analyses. CellphoneDB was utilized to analyze intercellular communication.

Results

It was found that cells in the 13th gestational week showed the lowest transcriptional level in each cluster in all stages. Nephron progenitors could be divided into four subgroups with diverse levels of autophagy corresponding to different SIX2 expressions. SSBpod (podocyte precursors) could differentiate into four types of podocytes (Pod), and autophagy-related regulation was involved in this process. Pseudotime analysis showed that interstitial progenitor cells (IPCs) potentially possessed two primitive directions of differentiation to interstitial cells with different expressions of autophagy. It was found that NPCs, pretubular aggregates and interstitial cell clusters had high abundance in Wilms tumor as compared with para-tumor samples with active intercellular communication.

Conclusions

All these findings suggest that autophagy may be involved in the development and cellular heterogeneity of early human fetal kidneys. In addition, part of Wilms tumor cancer cells possess the characteristics of some fetal renal cell clusters.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02154-w.

Role of FTO gene polymorphisms in Wilms tumor predisposition: A five-center case-control study

BACKGROUND

Wilms tumor is the most frequently occurring renal malignancy in pediatrics. The FTO gene exhibits a featured genetic contribution to cancer development. Nonetheless, its single nucleotide polymorphism (SNP) contribution to Wilms tumor remains unknown.

METHODS

In the present study, 402 Wilms tumor patients and 1198 healthy controls were successfully genotyped for FTO gene SNPs (rs1477196 G>A, rs9939609 T>A, rs7206790 C>G and rs8047395 A>G) using TaqMan SNP genotyping assays. Odds ratios (ORs) and 95% confidence intervals (CIs), generated from unconditional logistic regression, were applied to quantify the effects of FTO gene SNPs on Wilms tumor risk.

RESULTS

We found that the rs8047395 A>G polymorphism was significantly correlated with an increased risk for Wilms tumor (GG versus AA/AG: adjusted OR = 1.38, 95% CI = 1.04-1.85, p = 0.027). Carriers with 1 and 1-2 risk genotypes are more susceptible of developing Wilms tumor than those without risk genotypes. Stratified analysis of rs8047395 and risk genotypes revealed more significant relationships with Wilms tumor risk in certain subgroups. Preliminary functional annotations revealed that the rs8047395 A allele increases expression levels of the FTO gene as determined by expression quantitative trait locus analysis.

CONCLUSIONS

The present study provides evidence that rs8047395 may regulate FTO gene expression and thus confer susceptibility to Wilms tumor. The candidate FTO gene rs8047395 A>G polymorphism identified in this study warrants independent investigation.

Every Beat You Take-The Wilms' Tumor Suppressor WT1 and the Heart

Nearly three decades ago, the Wilms’ tumor suppressor Wt1 was identified as a crucial regulator of heart development. Wt1 is a zinc finger transcription factor with multiple biological functions, implicated in the development of several organ systems, among them cardiovascular structures. This review summarizes the results from many research groups which allowed to establish a relevant function for Wt1 in cardiac development and disease. During development, Wt1 is involved in fundamental processes as the formation of the epicardium, epicardial epithelial-mesenchymal transition, coronary vessel development, valve formation, organization of the cardiac autonomous nervous system, and formation of the cardiac ventricles. Wt1 is further implicated in cardiac disease and repair in adult life. We summarize here the current knowledge about expression and function of Wt1 in heart development and disease and point out controversies to further stimulate additional research in the areas of cardiac development and pathophysiology. As re-activation of developmental programs is considered as paradigm for regeneration in response to injury, understanding of these processes and the molecules involved therein is essential for the development of therapeutic strategies, which we discuss on the example of WT1.

The Legend of the Buffalo Chest

Background

The “buffalo chest” is a condition in which a simultaneous bilateral pneumothorax occurs due to a communication of both pleural cavities caused by an iatrogenic or idiopathic fenestration of the mediastinum. This rare condition is known by many clinicians because of a particular anecdote which stated that Native Americans could kill a North American bison with a single arrow in the chest by creating a simultaneous bilateral pneumothorax, due to the animal’s peculiar anatomy in which there is one contiguous pleural space due to an incomplete mediastinum.

Research Question

What evidence is there for the existence of buffalo chest?

Study Design and Methods

The term “buffalo chest” and its anecdote were first mentioned in a ‘‘personal communication’’ by a veterinarian in the Annals of Surgery in 1984. A mixed method research was performed on buffalo chest and its etiology. A total of 47 cases of buffalo chest were identified in humans.

Results

This study found that all authors were referring to the article from 1984 or to each other. Evidence was found for interpleural communications in other mammal species, but no literature on the anatomy of the mediastinum of the bison was found. The main reason for this research was fact-checking the origin of the anecdote and search for evidence for the existence of buffalo chest. Autopsies were performed on eight bison, and four indeed were found to have had interpleural communications.

Interpretation

We hypothesize that humans can also have interpleural fenestrations, which can be diagnosed when a pneumothorax occurs.

Impact of YTHDF1 gene polymorphisms on Wilms tumor susceptibility: A five-center case-control study

Background

Wilms tumor is the most frequent renal malignancy in children. YTHDF1 is associated with the development of several kinds of cancers, yet whether common variants of the YTHDF1 gene influence Wilms tumor risk is unknown. We present, here, a hospital‐based case‐control study specifically designed to investigate the role of YTHDF1 genetic variants on Wilms tumor.

Methods

We successfully genotyped samples of 408 Wilms tumor cases and 1198 controls which were collected from five hospitals across China. The unconditional logistic regression was adopted to analyze the contributions of YTHDF1 gene single nucleotide polymorphisms (SNPs) to the risk of Wilms tumor. The odds ratio (OR) and 95% confidence interval (CI) were generated to evaluate the conferring risk of YTHDF1 gene SNPs (rs6011668 C>T, rs6090311 A>G).

Results

Neither of the two SNPs could contribute to the risk of Wilms tumor. A negative association was also detected in the combined effects of protective genotypes on Wilms tumor risk. The stratification analysis revealed that compared with those with CC genotype, rs6011668 CT/TT genotype was associated with increased Wilms tumor risk in those ≤18 months (OR = 1.54, 95% CI = 1.02–2.30, p = 0.038), and with decreased Wilms tumor risk in those >18 months (OR = 0.70, 95% CI = 0.50–0.97, p = 0.034).

Conclusion

Our present work sheds some light on the potential role of YTHDF1 gene polymorphisms on Wilms tumor risk.

Implications of the Wilms' Tumor Suppressor Wt1 in Cardiomyocyte Differentiation

The Wilms’ tumor suppressor Wt1 is involved in multiple developmental processes and adult tissue homeostasis. The first phenotypes recognized in Wt1 knockout mice were developmental cardiac and kidney defects. Wt1 expression in the heart has been described in epicardial, endothelial, smooth muscle cells, and fibroblasts. Expression of Wt1 in cardiomyocytes has been suggested but remained a controversial issue, as well as the role of Wt1 in cardiomyocyte development and regeneration after injury. We determined cardiac Wt1 expression during embryonic development, in the adult, and after cardiac injury by quantitative RT-PCR and immunohistochemistry. As in vitro model, phenotypic cardiomyocyte differentiation, i.e., the appearance of rhythmically beating clones from mouse embryonic stem cells (mESCs) and associated changes in gene expression were analyzed. We detected Wt1 in cardiomyocytes from embryonic day (E10.5), the first time point investigated, until adult age. Cardiac Wt1 mRNA levels decreased during embryonic development. In the adult, Wt1 was reactivated in cardiomyocytes 48 h and 3 weeks following myocardial infarction. Wt1 mRNA levels were increased in differentiating mESCs. Overexpression of Wt1(-KTS) and Wt1(+KTS) isoforms in ES cells reduced the fraction of phenotypically cardiomyocyte differentiated clones, which was preceded by a temporary increase in c-kit expression in Wt1(-KTS) transfected ES cell clones and induction of some cardiomyocyte markers. Taken together, Wt1 shows a dynamic expression pattern during cardiomyocyte differentiation and overexpression in ES cells reduces their phenotypical cardiomyocyte differentiation.

Targeting loss of heterozygosity for cancer-specific immunotherapy

Developing therapeutic agents with potent antitumor activity that spare normal tissues remains a significant challenge. Clonal loss of heterozygosity (LOH) is a widespread and irreversible genetic alteration that is exquisitely specific to cancer cells. We hypothesized that LOH events can be therapeutically targeted by "inverting" the loss of an allele in cancer cells into an activating signal. Here we describe a proof-of-concept approach utilizing engineered T cells approximating NOT-gate Boolean logic to target counterexpressed antigens resulting from LOH events in cancer. The NOT gate comprises a chimeric antigen receptor (CAR) targeting the allele of human leukocyte antigen (HLA) that is retained in the cancer cells and an inhibitory CAR (iCAR) targeting the HLA allele that is lost in the cancer cells. We demonstrate that engineered T cells incorporating such NOT-gate logic can be activated in a genetically predictable manner in vitro and in mice to kill relevant cancer cells. This therapeutic approach, termed NASCAR (Neoplasm-targeting Allele-Sensing CAR), could, in theory, be extended to LOH of other polymorphic genes that result in altered cell surface antigens in cancers.

Clinical characteristics and outcomes of children with WAGR syndrome and Wilms tumor and/or nephroblastomatosis: The 30-year SIOP-RTSG experience

BACKGROUND

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare contiguous gene deletion syndrome with a 45% to 60% risk of developing Wilms tumor (WT). Currently, surveillance and treatment recommendations are based on limited evidence.

METHODS

Clinical characteristics, treatments, and outcomes were analyzed for patients with WAGR and WT/nephroblastomatosis who were identified through International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) registries and the SIOP-RTSG network (1989-2019). Events were defined as relapse, metachronous tumors, or death.

RESULTS

Forty-three patients were identified. The median age at WT/nephroblastomatosis diagnosis was 22 months (range, 6-44 months). The overall stage was available for 40 patients, including 15 (37.5%) with bilateral disease and none with metastatic disease. Histology was available for 42 patients; 6 nephroblastomatosis without further WT and 36 WT, including 19 stromal WT (52.8%), 12 mixed WT (33.3%), 1 regressive WT (2.8%) and 2 other/indeterminable WT (5.6%). Blastemal type WT occurred in 2 patients (5.6%) after prolonged treatment for nephroblastomatosis; anaplasia was not reported. Nephrogenic rests were present in 78.9%. Among patients with WT, the 5-year event-free survival rate was 84.3% (95% confidence interval, 72.4%-98.1%), and the overall survival rate was 91.2% (95% confidence interval, 82.1%-100%). Events (n = 6) did not include relapse, but contralateral tumor development (n = 3) occurred up to 7 years after the initial diagnosis, and 3 deaths were related to hepatotoxicity (n = 2) and obstructive ileus (n = 1).

CONCLUSIONS

Patients with WAGR have a high rate of bilateral disease and no metastatic or anaplastic tumors. Although they can be treated according to existing WT protocols, intensive monitoring of toxicity and surveillance of the remaining kidney(s) are advised.

LAY SUMMARY

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare genetic condition with an increased risk of developing Wilms tumor. In this study, 43 patients with WAGR and Wilms tumor (or Wilms tumor precursor lesions/nephroblastomatosis) were identified through the international registry of the International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) and the SIOP-RTSG network. In many patients (37.5%), both kidneys were affected. Disease spread to other organs (metastases) did not occur. Overall, this study demonstrates that patients with WAGR syndrome and Wilms tumor can be treated according to existing protocols. However, intensive monitoring of treatment complications and surveillance of the remaining kidney(s) are advised.

Comprehensive Analysis of a Long Noncoding RNA-Associated Competing Endogenous RNA Network in Wilms Tumor

Long noncoding RNA (lncRNA) plays crucial roles in various biological processes of different cancers, especially acting as a competing endogenous RNA (ceRNA). However, the role of lncRNA-mediated ceRNA in Wilms tumor (WT), which is the most common malignant kidney cancer in children, remains unknown. In present study, RNA sequence profiles and clinical data of 125 patients with WT consisting of 119 tumor and 6 normal tissues from Therapeutically Applicable Research To Generate Effective Treatments database were analyzed. A total of 1833 lncRNAs, 156 microRNAs (miRNAs), and 3443 messenger RNAs (mRNAs) were identified as differentially expressed (DE) using "DESeq2" package. The lncRNA-miRNA-mRNA ceRNA regulatory network involving 748 DElncRNAs, 33 DEmiRNAs, and 189 DEmRNAs was constructed based on miRcode, Targetscan, miRTarBase, and miRDB database. Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that DEmRNAs were mainly enriched in cell proliferation-related processes and tumor-related pathways, respectively, and 13 hub genes were identified by a protein-protein interaction network. Survival analysis detected 48 lncRNAs, 7 miRNAs, and 16 mRNAs to have significant impact on the overall survival of patients with WT. Additionally, we found that 6 DElncRNAs with potential prognostic value were correlated with tumor stage (DENND5B-AS1) and histologic classification (TMPO-AS1, RP3-523K23.2, RP11-598F7.3, LAMP5-AS1, and AC013275.2) of patients with WT. Our research provides a great insight into understanding the molecular mechanism underlying occurrence and progression of WT, as well as the potential to develop targeted therapies and prognostic biomarkers.

The contribution of YTHDF2 gene rs3738067 A>G to the Wilms tumor susceptibility

YTHDF2 is responsible for maintaining the dynamic N⁶-methyladenosine (m⁶A) modification balance and influences a variety of cancers. We tested whether YTHDF2 gene rs3738067 A>G polymorphism is related to Wilms tumor by genotyping samples of Chinese children (450 cases and 1317 controls). However, the rs3738067 A>G polymorphism showed no statistical significance with Wilms tumor susceptibility. Stratification analysis also revealed that there was no remarkable association of rs3738067 variant AG/GG genotype with Wilms tumor risk in every subgroup (age, gender, and clinical stages). In all, the results indicated YTHDF2 gene rs3738067 A>G polymorphism could not alter Wilms tumor risk significantly.

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.

Clinical features and prognosis of normal karyotype acute myeloid leukemia pediatric patients with WT1 mutations: an analysis based on TCGA database

Objectives: To explore the clinical features and prognosis of normal karyotype acute myeloid leukemia (NK-AML) pediatric patients with WT1 mutations.Methods: The clinical data and prognostic information of 220 NK-AML pediatric patients were selected from target-AML project of The Cancer Genome Atlas (TCGA) database. Survival analyses were performed for NK-AML pediatric patients with different combinations of mutations.Results: We found that 28(12.7%) NK-AML patients harbored WT1 mutations. The positive rate of FLT3-ITD in the WT1-mutated group was higher than that in the WT1 wild-type group (P = 0.002). In contrast, WT1 mutation and NPM1 mutation were mutually exclusive (P = 0.013). Furthermore, the WT1-mutated group suffered lower rates of complete remission (CR) (P < 0.001 and P < 0.001, respectively) but higher rates of minimal residual disease (MRD) (P = 0.003 and P = 0.021, respectively) after both one and two courses of induction chemotherapy. Patients with WT1 mutations had significantly worse overall survival (OS) and event-free survival (EFS) in both univariate (P < 0.001 and P = 0.007, respectively) and multivariate survival analyses (P < 0.001 and P < 0.001, respectively). The stratification analysis showed that for FLT3-ITD positive patients, WT1 mutations predicted shorter OS (P = 0.003) and EFS (P < 0.001).Conclusion: WT1 mutations conferred an independent poor prognosis for NK-AML pediatric patients.

Expansion of the renal capsular stroma, ureteric bud branching defects and cryptorchidism in mice with Wilms tumor 1 gene deletion in the stromal compartment of the developing kidney

Development of the mammalian kidney is orchestrated by reciprocal interactions of stromal and nephrogenic mesenchymal cells with the ureteric bud epithelium. Previous work showed that the transcription factor Wilms tumor 1 (WT1) acts in the nephrogenic lineage to maintain precursor cells, to drive the epithelial transition of aggregating precursors into a renal vesicle and to specify and maintain the podocyte fate. However, WT1 is expressed not only in the nephrogenic lineage but also transiently in stromal progenitors in the renal cortex. Here we report that specific deletion of Wt1 in the stromal lineage using the Foxd1^cre driver line results at birth in cryptorchidism and hypoplastic kidneys that harbour fewer and enlarged ureteric bud tips and display an expansion of capsular stroma into the cortical region. In vivo and ex vivo analysis at earlier stages revealed that stromal loss of Wt1 reduces stromal proliferation, and delays and alters branching morphogenesis, resulting in a variant architecture of the collecting duct tree with an increase of single at the expense of bifurcated ureteric bud tips. Molecular analysis identified a transient reduction of Aldh1a2 expression and of retinoic acid signalling activity in stromal progenitors, and of Ret in ureteric bud tips. Administration of retinoic acid partly rescued the branching defects of mutant kidneys in culture. We propose that WT1 maintains retinoic acid signalling in the cortical stroma, which, in turn, assures proper levels and dynamics of Ret expression in the ureteric bud tips, and thus normal ramification of the ureteric tree. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

The contribution of WTAP gene variants to Wilms tumor susceptibility

Wilms tumor is the most frequently occurring pediatric renal malignancy. Wilms tumor suppressor-1-associated protein (WTAP) is a vital component of N6-methyltransferase complex involved in tumorigenesis. However, the roles of WTAP gene single nucleotide polymorphisms (SNPs) in Wilms tumor risk have not been clarified to date. We successfully genotyped three WTAP gene SNPs using TaqMan assay in 405 Wilms tumor patients and 1197 cancer-free controls of Chinese children. Odds ratios (ORs) and 95% confidence intervals (CIs) were applied to determine the effects of WTAP gene SNPs on Wilms tumor risk. Carriers of the rs1853259 G variant are less susceptible to developing Wilms tumor, with an adjusted OR of 0.78 (AG vs. AA: 95% CI = 0.61-0.995, P = 0.046). Single locus analysis of rs9457712 G > A and rs7766006 G > T, as well as the combined analysis of risk genotypes, failed to unveil an association with Wilms tumor risk, respectively. Stratified analysis of the three SNPs and their combined risk effects showed more significant relationships with Wilms tumor risk under certain subgroups. In all, we found weak evidence of the association between WTAP gene SNPs and the risk of Wilms tumor. Further replication studies with greater sample size and different ethnicities are necessary to verify our findings.

ALKBH5 gene polymorphisms and Wilms tumor risk in Chinese children: A five-center case-control study

BACKGROUND

Wilms tumor is a frequently diagnosed renal cancer among children with unclear genetic causes. N6-methyladenosine (m⁶ A) modification genes play critical roles in tumorigenesis. However, whether genetic variations of m⁶ A modification genes predispose to Wilms tumor remain unclear. ALKBH5 (AlkB homolog 5), a crucial member of m⁶ A modification genes, encodes a demethylase that functions to reverse m⁶ A RNA methylation.

METHODS

Herein, we evaluated the association of single nucleotide polymorphisms (SNPs) in the m⁶ A modification gene ALKBH5 and Wilms tumor susceptibility in a large multi-center case-control study. A total of 414 Wilms tumor cases and 1199 healthy controls were genotyped for ALKBH5 rs1378602 and rs8400 polymorphisms by TaqMan.

RESULTS

No significant association was detected between these two polymorphisms and Wilms tumor risk. Moreover, 1, 2, and 1-2 protective genotypes (rs1378602 AG/AA or rs8400 GG) did not significantly reduce Wilms tumor risk, compared with risk genotypes only. Stratification analysis revealed a significant relationship between rs1378602 AG/AA genotypes and decreased Wilms tumor risk in children in clinical stage I diseases [adjusted odds ratio (OR) = 0.56, 95% confidence interval (CI) = 0.32-0.98, P = .042]. The presence of 1-2 protective genotypes was correlated with decreased Wilms tumor risk in subgroups of age > 18 months, when compared to the absence of protective genotypes (adjusted OR = 0.74, 95% CI = 0.56-0.98, P = .035).

CONCLUSION

Collectively, our results demonstrate that ALKBH5 SNPs may exert a weak influence on susceptibility to Wilms tumor. This finding increases the understanding of the role of the m⁶ A gene in tumorigenesis of Wilms tumor.

RNA-Binding Proteins in Acute Leukemias

Acute leukemias are genetic diseases caused by translocations or mutations, which dysregulate hematopoiesis towards malignant transformation. However, the molecular mode of action is highly versatile and ranges from direct transcriptional to post-transcriptional control, which includes RNA-binding proteins (RBPs) as crucial regulators of cell fate. RBPs coordinate RNA dynamics, including subcellular localization, translational efficiency and metabolism, by binding to their target messenger RNAs (mRNAs), thereby controlling the expression of the encoded proteins. In view of the growing interest in these regulators, this review summarizes recent research regarding the most influential RBPs relevant in acute leukemias in particular. The reported RBPs, either dysregulated or as components of fusion proteins, are described with respect to their functional domains, the pathways they affect, and clinical aspects associated with their dysregulation or altered functions.

PPAR Beta/Delta and the Hallmarks of Cancer

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family. Three different isoforms, PPAR alpha, PPAR beta/delta and PPAR gamma have been identified. They all form heterodimers with retinoic X receptors to activate or repress downstream target genes dependent on the presence/absence of ligands and coactivators or corepressors. PPARs differ in their tissue expression profile, ligands and specific agonists and antagonists. PPARs attract attention as potential therapeutic targets for a variety of diseases. PPAR alpha and gamma agonists are in clinical use for the treatment of dyslipidemias and diabetes. For both receptors, several clinical trials as potential therapeutic targets for cancer are ongoing. In contrast, PPAR beta/delta has been suggested as a therapeutic target for metabolic syndrome. However, potential risks in the settings of cancer are less clear. A variety of studies have investigated PPAR beta/delta expression or activation/inhibition in different cancer cell models in vitro, but the relevance for cancer growth in vivo is less well documented and controversial. In this review, we summarize critically the knowledge of PPAR beta/delta functions for the different hallmarks of cancer biological capabilities, which interplay to determine cancer growth.

Expression of Wilm’s Tumor Gene (WT1) in Endometrium with Potential Link to Gestational Vascular Transformation

Background: Wilm’s tumor 1 gene (WT1) is a transcription factor with versatile cellular functions in embryonic development, the maintenance of adult tissue functions, and regeneration. WT1 is known to be regulated by progesterone and it is abundantly expressed in endometrium, but its function is unclear. Design: in this observational and descriptive study, WT1 expression was detected by immunohistochemical staining in endometrium of various physiological and pathological conditions. Result: WT1 was detected in endometrial stromal cells and vascular smooth muscle cells, in both proliferative and secretory phases of menstrual cycles. WT1 appeared increased in vascular smooth muscle cells in spiral artery in early pregnancy and it was also detected in regenerative endothelial cells and smooth muscle cells in decidual vasculopathy at term. WT1 expression appeared decreased in endometrial stromal cells in adenomyosis (endometriosis). Conclusion: WT1 potentially links the hormonal effects on endometrial decidualization and may play a role in gestational vascular transformation during pregnancy and restoration after pregnancy.

The role of WT1 in breast cancer: clinical implications, biological effects and molecular mechanism

Although Wilms' tumor gene 1 (WT1) was first cloned and identified as a tumor suppressor gene in nephroblastoma, subsequent studies have demonstrated that it can also play an oncogenic role in leukemia and various solid tumors. WT1 exerts biological functions with high tissue- and cell-specificity. This article reviews the relationship between WT1 and breast cancer from two aspects: (1) clinical application of WT1, including the relationship between expression of WT1 and prognosis of breast cancer patients, and its effectiveness as a target for comprehensive therapy of breast cancer; (2) the biological effects and molecular mechanisms of WT1 in the development and progression of breast cancer, including proliferation, apoptosis, invasion, and metastasis of breast cancer cells.

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.

Identification of key genes and microRNAs involved in kidney Wilms tumor by integrated bioinformatics analysis

Wilms tumor (WT) is one of the most common types of pediatric solid tumors; however, its molecular mechanisms remain unclear. The present study aimed to identify key genes and microRNAs (miRNAs), and to predict the underlying molecular mechanisms of WT using integrated bioinformatics analysis. Original gene expression profiles were downloaded from the Gene Expression Omnibus (GEO; accession, GSE66405) and The Cancer Genome Atlas (TCGA) databases. Similarly, miRNA expression patterns were downloaded from GEO (accession, GSE57370) and TCGA. R version 3.5.0 software was used to identify differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) using the limma and edgeR packages. Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses were performed to examine the biological functions of the DEGs. Additionally, a protein-protein interaction (PPI) network was constructed to screen hub gene modules using Cytoscape software. By predicting target genes of the DEMs and integrating them with DEGs, the present study constructed a miRNA-mRNA regulatory network to predict the possible molecular mechanism of WT. Expression of hub genes was validated using the Oncomine database. A total of 613 genes and 29 miRNAs were identified to be differentially expressed in WT. By constructing a PPI network and screening hub gene modules, 5 upregulated genes, including BUB1 mitotic checkpoint serine/threonine kinase, BUB1B mitotic checkpoint serine/threonine kinase B, cell division cycle protein 45, cyclin B2 and pituitary tumor-transforming 1. These genes were identified to be associated with the cell cycle pathway, which suggested that these genes may serve important roles in WT. In addition, a miRNA-mRNA regulatory network was constructed and comprised 16 DEMs and 19 DEGs. In conclusion, key genes, miRNAs and the mRNA-miRNA regulatory network identified in the present study may improve understanding of the underlying molecular mechanisms in the occurrence and development of WT, and may aid the identification of potential biomarkers and therapeutic targets.

Tracing the first hematopoietic stem cell generation in human embryo by single-cell RNA sequencing

Tracing the emergence of the first hematopoietic stem cells (HSCs) in human embryos, particularly the scarce and transient precursors thereof, is so far challenging, largely due to the technical limitations and the material rarity. Here, using single-cell RNA sequencing, we constructed the first genome-scale gene expression landscape covering the entire course of endothelial-to-HSC transition during human embryogenesis. The transcriptomically defined HSC-primed hemogenic endothelial cells (HECs) were captured at Carnegie stage (CS) 12–14 in an unbiased way, showing an unambiguous feature of arterial endothelial cells (ECs) with the up-regulation of RUNX1, MYB and ANGPT1. Importantly, subcategorizing CD34⁺CD45⁻ ECs into a CD44⁺ population strikingly enriched HECs by over 10-fold. We further mapped the developmental path from arterial ECs via HSC-primed HECs to hematopoietic stem progenitor cells, and revealed a distinct expression pattern of genes that were transiently over-represented upon the hemogenic fate choice of arterial ECs, including EMCN, PROCR and RUNX1T1. We also uncovered another temporally and molecularly distinct intra-embryonic HEC population, which was detected mainly at earlier CS 10 and lacked the arterial feature. Finally, we revealed the cellular components of the putative aortic niche and potential cellular interactions acting on the HSC-primed HECs. The cellular and molecular programs that underlie the generation of the first HSCs from HECs in human embryos, together with the ability to distinguish the HSC-primed HECs from others, will shed light on the strategies for the production of clinically useful HSCs from pluripotent stem cells.

Prolonged retention of liposomes in the pleural cavity of normal mice and high tumor distribution in mice with malignant pleural effusion, after intrapleural injection

Background: Intrapleural administration of compounds is a lung targeted, innovative therapeutic strategy for mesothelioma, which can be refined as a route for drug delivery that minimizes the potential for systemic toxicity. However, little is currently known about the retention of liposomal drugs at the site, after such topical administration. Purpose: To evaluate the retention of liposomes in lungs following intrapleural injection, and how this might be modulated by liposome properties and disease progression. Methods: DiR-incorporating liposomes with various lipid compositions and sizes were prepared, characterized (for size distribution and zeta potential) and injected intrapleurally in normal mice and mice with malignant pleural effusion (MPE). DiR retention in pleural cavity was followed by biofluorescence imaging. Results: Experimental results demonstrate that liposome size and PEG-coating, have a significant effect on residence time in the pleural cavity; negative surface charge does not. More than 20% liposomal-DiR is retained 24 d post-injection (in some cases), indicating the high potential towards localized diseases. Ex-vivo liposomal-DiR signal in tumors of MPE mice was similar to signal in liver, suggesting high tumor targeting potential of intrapleurally injected liposomes. Finally, no difference was noticed in liposomal-DiR retention between tumor-inoculated (MPE) and healthy mice, indicating the stability of liposomes in the presence of effusion (in MPE mice). Conclusion: The current study provides novel insights for using liposomes by intrapleural administration for the treatment of lung diseases.

Convergent evolution of 11p allelic loss in multifocal Wilms tumors arising in WT1 mutation carriers

Wilms tumors in patients with constitutional WT1 mutations are examples of Knudson's tumor suppressor paradigm, with somatic inactivation of the second allele occurring through 11p loss of heterozygosity. The time point of this second hit has remained unknown. We analyzed seven Wilms tumors from two patients with constitutional WT1 mutations by whole exome sequencing and genomic array. All tumors exhibited wild type WT1 loss through uniparental isodisomy. Each tumor had a unique genomic breakpoint in 11p, typically accompanied by a private activating mutation of CTNNB1. Hence, convergent evolution rather than field carcinogenesis underlies multifocal tumors in WT1 mutation carriers.

The genetic architecture of aniridia and Gillespie syndrome

Absence of part or all of the iris, aniridia, is a feature of several genetically distinct conditions. This review focuses on iris development and then the clinical features and molecular genetics of these iris malformations. Classical aniridia, a panocular eye malformation including foveal hypoplasia, is the archetypal phenotype associated with heterozygous PAX6 loss-of-function mutations. Since this was identified in 1991, many genetic mechanisms of PAX6 inactivation have been elucidated, the commonest alleles being intragenic mutations causing premature stop codons, followed by those causing C-terminal extensions. Rarely, aniridia cases are associated with FOXC1, PITX2 and/or their regulatory regions. Aniridia can also occur as a component of many severe global eye malformations. Gillespie syndrome—a triad of partial aniridia, non-progressive cerebellar ataxia and intellectual disability—is phenotypically and genotypically distinct from classical aniridia. The causative gene has recently been identified as ITPR1. The same characteristic Gillespie syndrome-like iris, with aplasia of the pupillary sphincter and a scalloped margin, is seen in ACTA2-related multisystemic smooth muscle dysfunction syndrome. WAGR syndrome (Wilms tumour, aniridia, genitourinary anomalies and mental retardation/intellectual disability), is caused by contiguous deletion of PAX6 and WT1 on chromosome 11p. Deletions encompassing BDNF have been causally implicated in the obesity and intellectual disability associated with the condition. Lastly, we outline a genetic investigation strategy for aniridia in light of recent developments, suggesting an approach based principally on chromosomal array and gene panel testing. This strategy aims to test all known aniridia loci—including the rarer, life-limiting causes—whilst remaining simple and practical.

Genetic and epigenetic evolution as a contributor to WT1-mutant leukemogenesis

Genetic studies have identified recurrent somatic mutations in acute myeloid leukemia (AML) patients, including in the Wilms' tumor 1 (WT1) gene. The molecular mechanisms by which WT1 mutations contribute to leukemogenesis have not yet been fully elucidated. We investigated the role of Wt1 gene dosage in steady-state and pathologic hematopoiesis. Wt1 heterozygous loss enhanced stem cell self-renewal in an age-dependent manner, which increased stem cell function over time and resulted in age-dependent leukemic transformation. Wt1-haploinsufficient leukemias were characterized by progressive genetic and epigenetic alterations, including those in known leukemia-associated alleles, demonstrating a requirement for additional events to promote hematopoietic transformation. Consistent with this observation, we found that Wt1 depletion cooperates with Flt3-ITD mutation to induce fully penetrant AML. Our studies provide insight into mechanisms of Wt1-loss leukemogenesis and into the evolutionary events required to induce transformation of Wt1-haploinsufficient stem/progenitor cells.

Wilms' tumor 1 (WT1) as a prognosis factor in gynecological cancers: A meta-analysis

The oncogenic role of Wilms' tumor 1 (WT1) which is regarded as a promising target antigen for cancer immunotherapy has been demonstrated in many types of cancer, but the relationship between expression of WT1 and the prognosis value in gynecological cancer reminds unclear.We performed a meta-analysis with thirteen published studies including 2205 patients searched from PubMed, EMBASE, Web of Science, and Google Scholar, whose results are expressed by overall survival (OS) or disease-specific survival (DSS) or disease-free survival or relapse/recurrence-free survival (RFS) or progression-free survival (PFS) in patients with gynecological cancer. The hazard ratio (HR) with its 95% confidence interval (CI) were calculated to investigate prognostic of WT1 expression in patients with gynecological cancer.Finally, the overexpression of WT1 was borderlinely associated with poor OS (metaHR = 1.51, 95% CI = 0.98-2.31) in univariate model. We found a significant association with poor DSS (metaHR = 1.61, 95% CI = 1.24-2.08) and DFS/RFS/PFS (metaHR = 2.06, 95% CI = 1.22-3.46). The subgroup analyses revealed that the expression of WT1 predicted the poor DSS (metaHR = 1.82, 95% CI = 1.42-2.73), and DFS/RFS/PFS (metaHR = 2.51, 95% CI = 1.81-3.48) in patients with ovarian cancer. In summary, WT1 overexpression indicates a poor prognosis in patients with some gynecological tumors, but more studies are needed to confirm these findings.

Germline mutations and somatic inactivation of TRIM28 in Wilms tumour

Wilms tumour is a childhood tumour that arises as a consequence of somatic and rare germline mutations, the characterisation of which has refined our understanding of nephrogenesis and carcinogenesis. Here we report that germline loss of function mutations in TRIM28 predispose children to Wilms tumour. Loss of function of this transcriptional co-repressor, which has a role in nephrogenesis, has not previously been associated with cancer. Inactivation of TRIM28, either germline or somatic, occurred through inactivating mutations, loss of heterozygosity or epigenetic silencing. TRIM28-mutated tumours had a monomorphic epithelial histology that is uncommon for Wilms tumour. Critically, these tumours were negative for TRIM28 immunohistochemical staining whereas the epithelial component in normal tissue and other Wilms tumours stained positively. These data, together with a characteristic gene expression profile, suggest that inactivation of TRIM28 provides the molecular basis for defining a previously described subtype of Wilms tumour, that has early age of onset and excellent prognosis.

The germline and somatic molecular events associated with Wilms tumour, a childhood kidney cancer, have been progressively defined over the past three decades. Among the uncharacterised tumours are a group of tumours that have monomorphic epithelial histology, familial association, distinctively clustered gene-expression patterns, early age of diagnosis, and excellent prognosis. Here, we describe germline mutations and loss of function of TRIM28 in familial Wilms tumours, along with somatic loss of function in a non-familial Wilms tumour. All TRIM28-mutant tumours showed the rare monomorphic epithelial histology, suggesting that loss of TRIM28 expression could be a useful marker to define a group of tumours with excellent prognosis. Future studies could lead to identification and reassurance of families that carry TRIM28 mutations, and to the use of reduced intensity of treatment for children who develop TRIM28-null tumours.

Function and Regulation of the Wilms' Tumor Suppressor 1 (WT1) Gene in Fish

The Wilms' tumor suppressor gene Wt1 is highly conserved among vertebrates. In contrast to mammals, most fish species possess two wt1 paralogs that have been named wt1a and wt1b. Concerning wt1 in fish, most work so far has been done using zebrafish, focusing on the embryonic kidney, the pronephros. In this chapter we will describe the structure and development of the pronephros as well as the role that the wt1 genes play in the embryonic zebrafish kidney. We also discuss Wt1 target genes and describe the potential function of the Wt1 proteins in the adult kidney. Finally we will summarize data on the role of Wt1 outside of the kidney.

Wilms' tumor gene 1 silencing inhibits proliferation of human osteosarcoma MG-63 cell line by cell cycle arrest and apoptosis activation

Wilms’ tumor gene 1 (WT1) plays complex roles in tumorigenesis, acting as tumor suppressor gene or an oncogene depending on the cellular context. A high WT1 expression level was described in various types of human bone and soft-tissue sarcomas, including osteosarcoma (OS), but its function in carcinogenesis is not yet well understood. This study investigated WT1 both in human OS tissues and in human OS MG-63 cell line in which WT1 gene is up-regulated. The results demonstrated that WT1 is expressed in 50% of human OS cases. WT1-silenced MG-63 cells showed deregulation of proteins of cell cycle and down-regulation of PI3K/AKT pathway. Induction of apoptotic programme was also established by activation of caspase-3 and increase of Bax/Bcl2 ratio and p53 protein. This study provided new findings on role of WT1 and indicated an association between WT1 expression, cell cycle and apoptotic machinery. In conclusion, WT1 acts as a tumour promoter in osteosarcoma and it could be a potential therapeutic target.

Why boys will be boys and girls will be girls: Human sex development and its defects

Among the most defining events of an individual's life, is the development of a human embryo into male or a female. The phenotypic sex of an individual depends on the type of gonad that develops in the embryo, a process which itself is determined by the genetic setting of the individual. The development of the gonads is different from any other organ, as they possess the potential to differentiate into two functionally distinct organs, testes, or ovaries. Sex development can be divided into two distinctive processes, "sex determination," which is the commitment of the undifferentiated gonad into either a testis or an ovary, a process that is genetically programmed in a critically timed manner and "sex differentiation," which takes place through hormones produced by the gonads, once the developmental sex determination decision has been made. Disruption of any of the genes involved in either the testicular or ovarian development pathway could lead to disorders of sex development. In this review, we provide an insight into the factors important for sex determination, their antagonistic actions and whenever possible, references on the "prismatic" clinical cases are given. Birth Defects Research (Part C) 108:365-379, 2016. © 2016 Wiley Periodicals, Inc.

The transcriptional coregulator NAB2 is a target gene for the Wilms' tumor gene 1 protein (WT1) in leukemic cells

The Wilms’ tumor gene 1 (WT1) is recurrently mutated in acute myeloid leukemia. Mutations and high expression of WT1 associate with a poor prognosis. In mice, WT1 cooperates with the RUNX1/RUNX1T1 (AML1/ETO) fusion gene in the induction of acute leukemia, further emphasizing a role for WT1 in leukemia development. Molecular mechanisms for WT1 are, however, incompletely understood. Here, we identify the transcriptional coregulator NAB2 as a target gene of WT1. Analysis of gene expression profiles of leukemic samples revealed a positive correlation between the expression of WT1 and NAB2, as well as a non-zero partial correlation. Overexpression of WT1 in hematopoietic cells resulted in increased NAB2 levels, while suppression of WT1 decreased NAB2 expression. WT1 bound and transactivated the proximal NAB2 promoter, as shown by ChIP and reporter experiments, respectively. ChIP experiments also revealed that WT1 can recruit NAB2 to the IRF8 promoter, thus modulating the transcriptional activity of WT1, as shown by reporter experiments. Our results implicate NAB2 as a previously unreported target gene of WT1 and that NAB2 acts as a transcriptional cofactor of WT1.

The Battle of the Sexes: Human Sex Development and Its Disorders

The process of sexual differentiation is central for reproduction of almost all metazoan and therefore for maintenance of practically all multicellular organisms. In sex development we can distinguish two different processes: First, sex determination is the developmental decision that directs the undifferentiated embryo into a sexually dimorphic individual. In mammals, sex determination equals gonadal development. The second process known as sex differentiation takes place once the sex determination decision has been made through factors produced by the gonads that determine the development of the phenotypic sex. Most of the knowledge on the factors involved in sexual development came from animal models and from studies of cases in whom the genetic or the gonadal sex does not match the phenotypical sex, i.e., patients affected by disorders of sex development (DSD). Generally speaking, factors influencing sex determination are transcriptional regulators, whereas factors important for sex differentiation are secreted hormones and their receptors. This review focuses on the factors involved in gonadal determination, and whenever possible, references on the "prismatic" clinical cases are given.

Distinct global binding patterns of the Wilms tumor gene 1 (WT1) -KTS and +KTS isoforms in leukemic cells

The zinc finger transcription factor Wilms tumor gene 1 (WT1) acts as an oncogene in acute myeloid leukemia. A naturally occurring alternative splice event between zinc fingers three and four, removing or retaining three amino acids (±KTS), is believed to change the DNA binding affinity of WT1, although there are conflicting data regarding the binding affinity and motifs of the different isoforms. Increased expression of the WT1 -KTS isoform at the expense of the WT1 +KTS isoform is associated with poor prognosis in acute myeloid leukemia. We determined the genome-wide binding pattern of WT1 -KTS and WT1 +KTS in leukemic K562 cells by chromatin immunoprecipitation and deep sequencing. We discovered that the WT1 -KTS isoform predominantly binds close to transcription start sites and to enhancers, in a similar fashion to other transcription factors, whereas WT1 +KTS binding is enriched within gene bodies. We observed a significant overlap between WT1 -KTS and WT1 +KTS target genes, despite the binding sites being distinct. Motif discovery revealed distinct binding motifs for the isoforms, some of which have been previously reported as WT1 binding sites. Additional analyses showed that both WT1 -KTS and WT1 +KTS target genes are more likely to be transcribed than non-targets, and are involved in cell proliferation, cell death, and development. Our study provides evidence that WT1 -KTS and WT1 +KTS share target genes yet still bind distinct locations, indicating isoform-specific regulation in transcription of genes related to cell proliferation and differentiation, consistent with the involvement of WT1 in acute myeloid leukemia.

The expanding phenotypic spectra of kidney diseases: insights from genetic studies

Next-generation sequencing (NGS) has led to the identification of previously unrecognized phenotypes associated with classic kidney disease genes. In addition to improving diagnostics for genetically heterogeneous diseases and enabling a faster rate of gene discovery, NGS has enabled an expansion and redefinition of nephrogenetic disease categories. Findings from these studies raise the question of whether disease diagnoses should be made on clinical grounds, on genetic evidence or a combination thereof. Here, we discuss the major kidney disease-associated genes and gene categories for which NGS has expanded the phenotypic spectrum. For example, COL4A3-5 genes, which are classically associated with Alport syndrome, are now understood to also be involved in the aetiology of focal segmental glomerulosclerosis. DGKE, which is associated with nephrotic syndrome, is also mutated in patients with atypical haemolytic uraemic syndrome. We examine how a shared genetic background between diverse clinical phenotypes can provide insight into the function of genes and novel links with essential pathophysiological mechanisms. In addition, we consider genetic and epigenetic factors that contribute to the observed phenotypic heterogeneity of kidney diseases and discuss the challenges in the interpretation of genetic data. Finally, we discuss the implications of the expanding phenotypic spectra associated with kidney disease genes for clinical practice, genetic counselling and personalized care, and present our recommendations for the use of NGS-based tests in routine nephrology practice.