Role of CD56 in Normal Kidney Development and Wilms Tumorigenesis

Exploiting embryonic niche conditions to grow Wilms tumor blastema in culture

Introduction

Wilms Tumor (WT), or nephroblastoma, is the most common pediatric kidney cancer. Most WTs display a “favorable” triphasic histology, in which the tumor is comprised of blastemal, stromal, and epithelial cell types. Blastemal predominance after neoadjuvant chemotherapy or diffuse anaplasia (“unfavorable” histology; 5-8%) portend a worse prognosis. Blastema likely provide the putative cancer stem cells (CSCs), which retain molecular and histologic features characteristic of nephron progenitor cells (NPCs), within WTs. NPCs arise in the metanephric mesenchyme (MM) and populate the cap mesenchyme (CM) in the developing kidney. WT blastemal cells, like NPCs, similarly express markers, SIX2 and CITED1. Tumor xenotransplantation is currently the only dependable method to propagate tumor tissue for research or therapeutic screening, since efforts to culture tumors in vitro as monolayers have invariably failed. Therefore, a critical need exists to propagate WT stem cells rapidly and efficiently for high-throughput, real-time drug screening.

Methods

Previously, our lab developed niche conditions that support the propagation of murine NPCs in culture. Applying similar conditions to WTs, we assessed our ability to maintain key NPC "stemness" markers, SIX2, NCAM, and YAP1, and CSC marker ALDHI in cells from five distinct untreated patient tumors.

Results

Accordingly, our culture conditions maintained the expression of these markers in cultured WT cells through multiple passages of rapidly dividing cells.

Discussion

These findings suggest that our culture conditions sustain the WT blastemal population, as previously shown for normal NPCs. As a result, we have developed new WT cell lines and a multi-passage in vitro model for studying the blastemal lineage/CSCs in WTs. Furthermore, this system supports growth of heterogeneous WT cells, upon which potential drug therapies could be tested for efficacy and resistance.

Unmet needs for relapsed or refractory Wilms tumour: Mapping the molecular features, exploring organoids and designing early phase trials - A collaborative SIOP-RTSG, COG and ITCC session at the first SIOPE meeting

Wilms tumour (WT) accounts for about 6% of all childhood cancers and overall survival of WT is about 90% in international protocols. However, for WT subgroups with much poorer prognoses, i.e. typically high-risk (unfavorable) histology and/or relapse, there is an unmet need to better understand the biology of WT and to translate biological findings into clinics through early phase clinical trials that evaluate innovative therapies. The main challenges are the small numbers of children suitable for early phase trials, the genetic heterogeneity of WT and the low number of somatic mutations that are currently considered 'druggable'. Accordingly, a joint meeting between clinical and biology experts from the international cooperative groups of the Renal Tumour Study Group of the International Society of Paediatric Oncology, the Renal Tumour Committee of the Children's Oncology Group and the European Innovative Therapies for Children with Cancer consortium and parents representatives was organised during the first SIOPE meeting in Prague, 2019. We reviewed WT molecular features, ongoing/planned early phase trials and explored available knowledge on organoid technology. The key messages were: (1) relapsed WT should undergo whenever possible thorough molecular characterization and be enrolled in protocols or trials with systematic data collecting and reporting; (2) WT displays few known 'actionable' targets and currently no novel agent has appeared promising; (3) we need to improve the enrolment rate of WT candidates in early phase trials especially for the relatively small subgroup of relapses with an adverse prognostic signature; (4) despite some agnostic early phase trials existing, development of WT-focused trials are warranted; (5) growing organoids with parallel testing of drug panels seems feasible and may direct individual treatment and encourage clinical researchers to incorporate the most promising agents into early phase trials.

Multi-Omics Integration Reveals a Competitive Endogenous RNAs Network for the Identification of Progression Biomarkers and the Stratification of Patients Diagnosed With Nephroblastoma

Specific types of nephroblastoma (Wilms' tumor, WT) are known to associate with poor overall survival. Emerging experimental evidence has demonstrated that competitive endogenous RNA (ceRNA) networks have important roles in regulating cancer occurrence, but the roles of ceRNAs in regulating the WT progression and the patient outcomes remain unclear. Using the multi-omics data of 132 WT patients collected from TARGET database, an integration analysis pipeline was performed to construct a highly reliable ceRNA network. As results, a total of 147 nodes (116 mRNAs, 15 miRNAs, and 16 lncRNAs) were identified and used to explore the underlying mechanism for WT progression. WGCNA analysis further identified several prognostic molecules, including hsa-mir-93, LINC00087 and RP5-1086K13, that significantly associated with the overall survival rate. And, enrichment analysis verified the participation of these molecules in tumor-related pathways, such as those controlling autophagy and cadherin-mediated adhesion. Importantly, the WT patients were classified into three categories according to the ceRNA network, which significantly correlated with the overall survival. In conclusion, the ceRNA network could be a promising tool to further validate the prognostic biomarkers and categories of patients diagnosed with WT.

Novel therapy for pediatric and adolescent kidney cancer

Pediatric and adolescent renal tumors account for approximately 7% of all new cancer diagnoses in the USA each year. The prognosis and treatment are varied based on factors including the underlying histology and tumor stage, with survival rates ranging from greater than 90% in favorable histology Wilms tumor to almost universally fatal in other disease types, including those patients with advanced stage malignant rhabdoid tumor and renal medullary carcinoma. In recent years, our understanding of the underlying genetic drivers of the different types of pediatric kidney cancer has dramatically increased, opening the door to utilization of new targeted biologic agents alone or in combination with conventional chemotherapy to improve outcomes. Several ongoing clinical trials are investigating the use of a variety of targeted agents in pediatric patients with underlying genetic aberrations. In this manuscript, the underlying biology and early phase clinical trials relevant to pediatric renal cancers are reviewed.

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.

β1 Integrins Are Required To Mediate NK Cell Killing of Cryptococcus neoformans

Cryptococcus neoformans is a fungal pathogen that causes fatal meningitis and pneumonia. During host defense to Cryptococcus, NK cells directly recognize and kill C. neoformans using cytolytic degranulation analogous to killing of tumor cells. This fungal killing requires independent activation of Src family kinase (SFK) and Rac1-mediated pathways. Recognition of C. neoformans requires the natural cytotoxicity receptor, NKp30; however, it is not known whether NKp30 activates both signal transduction pathways or whether a second receptor is involved in activation of one of the pathways. We used primary human NK cells and a human NK cell line and found that NKp30 activates SFK → PI3K but not Rac1 cytotoxic signaling, which led to a search for the receptor leading to Rac1 activation. We found that NK cells require integrin-linked kinase (ILK) to activate Rac1 for effective fungal killing. This observation led to our identification of β1 integrin as an essential anticryptococcal receptor. These findings demonstrate that multiple receptors, including β1 integrins and NKp30 and their proximal signaling pathways, are required for recognition of Cryptococcus, which activates a central cytolytic antimicrobial pathway leading to fungal killing.

Review of phase I and II trials for Wilms' tumour - Can we optimise the search for novel agents?

Survival rates for patients with Wilms' tumour (WT) approximate 90% with refined use of currently available interventions. However, a subgroup of patients, with initial high-risk histopathology or relapsing disease, have a poor prognosis, and it is a challenge to identify and prioritise the development of new innovative approaches for these subgroups. We conducted a systematic literature search for published phase I and II clinical trials that registered patients with WTs and characterised the early phase trial activity, quantified response rates and highlighted avenues for further development. We identified 63 trials (48 phase I, three phase I/II, and 12 phase II trials) enrolling 214 patients with WTs, alongside other malignancies. The number of annually recruited WTs did not change significantly and was less than 20% of the potential candidates. The vast majority of the trials were conducted in North America, and 56 different interventions were investigated, including conventional chemotherapy and biologically targeted therapies. Overall, 33 WTs revealed some degree of tumour control. Of these, five patients demonstrated complete remission (2%), 15 patients partial response (7%) and 13 patients stable disease (6%). None of the included novel biologically targeted therapies emerged as promising interventions, and only conventional chemotherapy was able to induce a complete and partial response. We conclude that early phase trial recruitment of WTs is below expected levels, and the clinical outcome of the included patients is dismal. Improvement of the availability and recruitment to early phase trials for WTs, especially in Europe, is needed.