Expression of NRG1 and its receptors in human bladder cancer

Expert Consensus on the Diagnosis and Treatment of NRG1/2 Gene Fusion Solid Tumors

The fusion genes NRG1 and NRG2 , members of the epidermal growth factor (EGF) receptor family, have emerged as key drivers in cancer. Upon fusion, NRG1 retains its EGF-like active domain, binds to the ERBB ligand family, and triggers intracellular signaling cascades, promoting uncontrolled cell proliferation. The incidence of NRG1 gene fusion varies across cancer types, with lung cancer being the most prevalent at 0.19 to 0.27%. CD74 and SLC3A2 are the most frequently observed fusion partners. RNA-based next-generation sequencing is the primary method for detecting NRG1 and NRG2 gene fusions, whereas pERBB3 immunohistochemistry can serve as a rapid prescreening tool for identifying NRG1 -positive patients. Currently, there are no approved targeted drugs for NRG1 and NRG2 . Common treatment approaches involve pan-ERBB inhibitors, small molecule inhibitors targeting ERBB2 or ERBB3, and monoclonal antibodies. Given the current landscape of NRG1 and NRG2 in solid tumors, a consensus among diagnostic and treatment experts is proposed, and clinical trials hold promise for benefiting more patients with NRG1 and NRG2 gene fusion solid tumors.

Durable response to afatinib in advanced lung adenocarcinoma harboring a novel NPTN-NRG1 fusion: a case report

BACKGROUND

NRG1 fusions are rare oncogenic drivers in solid tumors, and the incidence of NRG1 fusions in non-small cell lung cancer (NSCLC) was 0.26%. It is essential to explore potential therapeutic strategies and efficacy predictors for NRG1 fusion-positive cancers.

CASE PRESENTATION

We report an advanced lung adenocarcinoma patient harboring a novel NPTN-NRG1 fusion identified by RNA-based next-generation sequencing (NGS), which was not detected by DNA-based NGS at initial diagnosis. Transcriptomics data of the tissue biopsy showed NRG1α isoform accounted for 30% of total NRG1 reads, and NRG1β isoform was undetectable. The patient received afatinib as fourth-line treatment and received a progression-free survival (PFS) of 14 months.

CONCLUSIONS

This report supports afatinib can provide potential benefit for NRG1 fusion patients, and RNA-based NGS is an accurate and cost-effective strategy for fusion detection and isoform identification.

Non-negative matrix factorization and differential expression analyses identify hub genes linked to progression and prognosis of glioblastoma multiforme

One of the most prevailing primary brain tumors in adult human male is glioblastoma multiforme (GBM), which is categorized by rapid cellular growth. Even though the combination therapy comprises surgery, chemotherapy, and adjuvant therapies, the survival rate, on average, is 14.6 months. Glioma stem cells (GSCs) have key roles in tumorigenesis, progression, and defiance against chemotherapy and radiotherapy. In our study, firstly, the gene expression dataset GSE124145 was retrieved; the non-negative matrix factorization (NMF) method was applied on GBM dataset, and differentially expressed genes analysis (DEGs) was performed. After which, overlapping genes between metagenes and DEGs were detected to examine the Gene Ontology (GO) categories in the biological process (BP) in the stemness of GBM. The common hub genes were used to construct protein-protein interaction (PPI) network and further GO, while Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was utilized to pinpoint the real hub genes. The analysis of hub genes particular for the same GO categories demonstrated that specific hub genes triggered distinct features of the same biological processes. After utilizing GSE124145 and The Cancer Genome Atlas (TCGA) dataset for survival analysis, we screened five real hub genes: GUCA1A, RFC2, GNG11, MMP19, and NRG1, which are strongly associated with the progression and prognosis of GBM. The DEGs analysis revealed that all real hub genes were overexpressed in GBM and TCGA datasets, which further validates our results. The constructed study of PPI, GO, and KEGG pathway on common hub genes was performed. Finally, the KEGG pathways performed on the top 15 candidate hub genes (including six real hub genes) of the PPI network in the GBM gene expression dataset study found mitogen-activated protein kinase (Mapk) signaling pathway to be the most significant pathway. The rest of the hub genes reviewed throughout the analysis might be favorable targets for diagnosing and treating GBM and lower-grade gliomas.

Frontiers in Bladder Cancer Genomic Research

Most of the etiology studies of bladder cancer focus on genetic changes, mainly including mutation and activation of oncogenes, mutation and inactivation of tumor suppressor genes, and rearrangement or heterozygous deletion of chromosomes. Moreover, bladder cancer is highly heterogeneous mainly due to abnormal changes in the genome and proteome of tumor cells. Surgery is the main treatment for bladder cancer, but because the recurrence rate is high after surgery and most of the muscle-invasive bladder cancer acquires distant metastasis. Therefore, there is a need to combine with chemotherapy to consolidate the treatment effect. However, there are differences in chemosensitivity among patients. In this article, we review the up-to-date genomic researches on bladder cancer occurrence, development, metastasis, and chemosensitivity in patients, in order to provide some theoretical support for the diagnosis and treatment strategy for bladder cancer.

Neuregulin-1-β1 and γ-secretase play a critical role in sphere-formation and cell survival of urothelial carcinoma cancer stem-like cells

Previously, we investigated gene expression in a high aldehyde dehydrogenase 1 expression (ALDH1^high) population of urothelial carcinoma (UC) cells as UC cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) and found that NRG1 expression was upregulated in ALDH1^high cells. NRG1 is a trophic factor that contains an epidermal growth factor (EGF)-like domain that signals by stimulating ERBB receptor tyrosine kinases and the cytoplasmic domain. NRG1 has been determined to be involved in frequent gene fusions with other partners in several malignancies and has a role in carcinogenesis through the NRG1 EGF-like domain and its cognitive receptor ERBBs. We thus aimed to elucidate the function of NRG1 in UC CSCs/CICs in this study. Both NRG1α and NRG1-β1 were preferentially expressed in ALDH1^high cells compared with ALDH1^low cells; however, siRNA experiments revealed that NRG1-β1 but not NRG1-α has a role in sphere formation. The EGF-like domain of NRG1 had a role in sphere formation of UC cells to some extent but was not essential. The intracellular domain of NRG1 did not have a role in sphere-formation. Inhibition of γ-secretase suppressed sphere formation. These findings indicate that cleavage of NRG1-β1 by γ-secretase plays an important role in UC CSC/CIC proliferation; however, the downstream targets of NRG1-β1 remain elusive.

Neuregulin 1 enhances cell adhesion molecule L1 like expression levels and promotes malignancy in human glioma

Neural cell adhesion molecular L1-like protein (CHL1) is a member of the cell adhesion molecule L1 family and serves an important role in the development and progression of tumors. The cytokine neuregulin 1 (NRG1) has been indicated in the tumorigenesis and promotion of metastasis through the modulation of L1. However, the roles of NRG1 in regulating CHL1 in glioma have not been elucidated. The present study investigated the protein expression levels and roles of CHL1 and the possible correlation between NRG1 and CHL1 protein expression levels in human gliomas, both in vivo and in vitro. Using immunohistochemistry coupled with a human glioma tissue microarray, it was demonstrated that the percentage of CHL1-positive areas was the highest in grade II glioma tissues. Using immunofluorescence staining, a positive correlation was identified between the expression levels of CHL1 and proliferating cell nuclear antigen. In addition, CHL1 downregulation also resulted in increased senescence of U-87 MG human glioblastoma cells. In vitro, administration of NRG1α induced a significant increase in CHL1 protein expression levels in human glioma SHG-44 and U251 cells and in human glioblastoma U-87 MG cells, whereas NRG1β failed to increase CHL1 expression levels in U251 cells. These findings were further confirmed by the downregulation of NRG1 expression levels using small interfering RNA treatment, which resulted in the reduction of CHL1 protein expression levels in U-87 MG cells. These data indicate that NRG1 can regulate CHL1 protein expression levels in gliomas, that it is correlated with malignancy, and that NRG1 may contribute to malignancy by upregulating CHL1 protein expression levels in glioma/glioblastoma cells.

The role of ErbB4 in cancer

BACKGROUND

The epidermal growth factor receptor family consists of four members, ErbB1 (epidermal growth factor receptor-1), ErbB2, ErbB3, and ErbB4, which all have been found to play important roles in tumor development. ErbB4 appears to be unique among these receptors, because it is the only member with growth inhibiting properties. ErbB4 plays well-defined roles in normal tissue development, in particular the heart, the nervous system, and the mammary gland system. In recent years, information on the role of ErbB4 in a number of tumors has emerged and its general direction points towards a tumor suppressor role for ErbB4. However, there are some controversies and conflicting data, warranting a review on this topic.

CONCLUSIONS

Here, we discuss the role of ErbB4 in normal physiology and in breast, lung, colorectal, gastric, pancreatic, prostate, bladder, and brain cancers, as well as in hepatocellular carcinoma, cholangiocarcinoma, and melanoma. Understanding the role of ErbB4 in cancer is not only important for the treatment of tumors, but also for the treatment of other disorders in which ErbB4 plays a major role, e.g. cardiovascular disease.

IPCT: Integrated Pharmacogenomic Platform of Human Cancer Cell Lines and Tissues

: (1) Motivation: The exponential increase in multilayered data, including omics, pathways, chemicals, and experimental models, requires innovative strategies to identify new linkages between drug response information and omics features. Despite the availability of databases such as the Cancer Cell Line Encyclopedia (CCLE), the Cancer Therapeutics Response Portal (CTRP), and The Cancer Genome Atlas (TCGA), it is still challenging for biologists to explore the relationship between drug response and underlying genomic features due to the heterogeneity of the data. In light of this, the Integrated Pharmacogenomic Database of Cancer Cell Lines and Tissues (IPCT) has been developed as a user-friendly way to identify new linkages between drug responses and genomic features, as these findings can lead not only to new biological discoveries but also to new clinical trials. (2) Results: The IPCT allows biologists to compare the genomic features of sensitive cell lines or small molecules with the genomic features of tumor tissues by integrating the CTRP and CCLE databases with the REACTOME, cBioPortal, and Expression Atlas databases. The input consists of a list of small molecules, cell lines, or genes, and the output is a graph containing data entities connected with the queried input. Users can apply filters to the databases, pathways, and genes as well as select computed sensitivity values and mutation frequency scores to generate a relevant graph. Different objects are differentiated based on the background color of the nodes. Moreover, when multiple small molecules, cell lines, or genes are input, users can see their shared connections to explore the data entities common between them. Finally, users can view the resulting graphs in the online interface or download them in multiple image or graph formats. (3) Availability and Implementation: The IPCT is available as a web application with an integrated MySQL database. The web application was developed using Java and deployed on the Tomcat server. The user interface was developed using HTML5, JQuery v.3.1.0 , and the Cytoscape Graph API v.1.0.4. The IPCT can be accessed at http://ipct.ewostech.net. The source code is available at https://github.com/muhammadshoaib/ipct.

Clinical significance of overexpression of NRG1 and its receptors, HER3 and HER4, in gastric cancer patients

BACKGROUND

Neuregulin 1 (NRG1), a ligand for human epidermal growth factor (HER) 3 and HER4, can activates cell signaling pathways to promote carcinogenesis and metastasis.

METHODS

To investigate the clinicopathologic significance of NRG1 and its receptors, immunohistochemistry was performed for NRG1, HER3, and HER4 in 502 consecutive gastric cancers (GCs). Furthermore, HER2, microsatellite instability (MSI), and Epstein-Barr virus (EBV) status were investigated. NRG1 gene copy number (GCN) was determined by dual-color fluorescence in situ hybridization (FISH) in 388 available GCs.

RESULTS

NRG1 overexpression was observed in 141 (28.1%) GCs and closely correlated with HER3 (P = 0.034) and HER4 (P < 0.001) expression. NRG1 overexpression was significantly associated with aggressive features, including infiltrative tumor growth, lymphovascular, and neural invasion, high pathologic stage, and poor prognosis (all P < 0.05), but not associated with EBV, MSI, or HER2 status. Multivariate analysis identified NRG1 overexpression as an independent prognostic factor for survival (P = 0.040). HER3 and HER4 expressions were observed in 157 (31.3%) and 277 (55.2%), respectively. In contrast to NRG1, expression of these proteins was not associated with survival. NRG1 GCN gain (GCN ≥ 2.5) was detected in 14.7% patients, including two cases of amplification, and was moderately correlated with NRG1 overexpression (κ, 0.459; P < 0.001).

CONCLUSIONS

Although our results indicate a lack of prognostic significance of HER3 and HER4 overexpression in GC, overexpression of their ligand, NRG1, was associated with aggressive clinical features and represented an independent unfavorable prognostic factor. Therefore, NRG1 is a potential prognostic and therapeutic biomarker in GC patients.

Neuregulin expression in solid tumors: prognostic value and predictive role to anti-HER3 therapies

BACKGROUND

Neuregulins (NRG) are a family of epidermal growth factor ligands which act through binding to HER3 and HER4 receptors. NRGs are widely expressed in solid tumors. Their prognostic significance or their role as predictors of benefit from anti-HER3 therapy is not known.

RESULTS

Of 29 included studies, 7 studies reported the association between NRG and outcome. NRG was most commonly expressed in breast, prostate, colon and bladder cancers. NRG expression was not associated with either OS or PFS (HR: 3.47, 95% CI 0.78-15.47, p = 0.10 and HR: 1.64, 95% CI 0.94-2.86, p = 0.08, respectively). In 4 placebo controlled trials of anti-HER3 therapy, the addition of anti-HER3 antibodies to control therapy in unselected patients was not associated with improved PFS (HR: 0.88, 95% CI 0.75-1.04. p = 0.14). However, in patients with high NRG expression, there was significantly delayed progression (HR: 0.35, 95% CI 0.23-0.52, p < 0.001). Anti-HER3 antibodies were associated with increased risk of diarrhea, nausea and rash.

METHODS

A search of electronically available databases identified studies exploring clinical outcomes based on NRG expression, as well as placebo-controlled trials of HER3-directed therapy reporting results based on NRG expression status. Data were combined in a meta-analysis using generic inverse variance and random effects modeling for studies reporting the hazard ratio (HR) for overall (OS) or progression-free survival (PFS). Mantel-Haenszel random-effect modeling was used for odds ratio (OR) for 3-year and 5-year OS and PFS.

CONCLUSIONS

NRG expression is not associated with either OS or PFS, but is a predictor of benefit from anti-HER3 antibodies.

Polycomb Repressor Complex 1 Member, BMI1 Contributes to Urothelial Tumorigenesis through p16-Independent Mechanisms

Urothelial carcinoma (UC) causes significant morbidity and remains the most expensive cancer to treat because of the need for repeated resections and lifelong monitoring for patients with non-muscle-invasive bladder cancer (NMIBC). Novel therapeutics and stratification approaches are needed to improve the outlook for both NMIBC and muscle-invasive bladder cancer. We investigated the expression and effects of B Lymphoma Mo-MLV Insertion Region 1 (BMI1) in UC. BMI1 was found to be overexpressed in most UC cell lines and primary tumors by quantitative real-time polymerase chain reaction and immunohistochemistry. In contrast to some previous reports, no association with tumor stage or grade was observed in two independent tumor panels. Furthermore, upregulation of BMI1 was detected in premalignant bladder lesions, suggesting a role early in tumorigenesis. BMI1 is not located within a common region of genomic amplification in UC. The CDKN2A locus (which encodes the p16 tumor suppressor gene) is a transcriptional target of BMI1 in some cellular contexts. In UC cell lines and primary tissues, no correlation between BMI1 and p16 expression was observed. Retroviral-mediated overexpression of BMI1 immortalized normal human urothelial cells (NHUC) in vitro and was associated with induction of telomerase activity, bypass of senescence, and repression of differentiation. The effects of BMI1 on gene expression were identified by expression microarray analysis of NHUC-BMI1. Metacore analysis of the gene expression profile implicated downstream effects of BMI1 on α4/β1 integrin-mediated adhesion, cytoskeleton remodeling, and CREB1-mediated transcription.

Molecular biology of bladder cancer: new insights into pathogenesis and clinical diversity

Urothelial carcinoma of the bladder comprises two long-recognized disease entities with distinct molecular features and clinical outcome. Low-grade non-muscle-invasive tumours recur frequently but rarely progress to muscle invasion, whereas muscle-invasive tumours are usually diagnosed de novo and frequently metastasize. Recent genome-wide expression and sequencing studies identify genes and pathways that are key drivers of urothelial cancer and reveal a more complex picture with multiple molecular subclasses that traverse conventional grade and stage groupings. This improved understanding of molecular features, disease pathogenesis and heterogeneity provides new opportunities for prognostic application, disease monitoring and personalized therapy.

Side population in human non-muscle invasive bladder cancer enriches for cancer stem cells that are maintained by MAPK signalling

Side population (SP) and ABC transporter expression enrich for stem cells in numerous tissues. We explored if this phenotype characterised human bladder cancer stem cells (CSCs) and attempted to identify regulatory mechanisms. Focusing on non-muscle invasive bladder cancer (NMIBC), multiple human cell lines were used to characterise SP and ABC transporter expression. In vitro and in vivo phenotypic and functional assessments of CSC behaviour were undertaken. Expression of putative CSC marker ABCG2 was assessed in clinical NMIBC samples (n = 148), and a role for MAPK signalling, a central mechanism of bladder tumourigenesis, was investigated. Results showed that the ABCG2 transporter was predominantly expressed and was up-regulated in the SP fraction by 3-fold (ABCG2(hi)) relative to the non-SP (NSP) fraction (ABCG2(low)). ABCG2(hi) SP cells displayed enrichment of stem cell markers (Nanog, Notch1 and SOX2) and a three-fold increase in colony forming efficiency (CFE) in comparison to ABCG2(low) NSP cells. In vivo, ABCG2(hi) SP cells enriched for tumour growth compared with ABCG2(low) NSP cells, consistent with CSCs. pERK was constitutively active in ABCG2(hi) SP cells and MEK inhibition also inhibited the ABCG2(hi) SP phenotype and significantly suppressed CFE. Furthermore, on examining clinical NMIBC samples, ABCG2 expression correlated with increased recurrence and decreased progression free survival. Additionally, pERK expression also correlated with decreased progression free survival, whilst a positive correlation was further demonstrated between ABCG2 and pERK expression. In conclusion, we confirm ABCG2(hi) SP enriches for CSCs in human NMIBC and MAPK/ERK pathway is a suitable therapeutic target.

Receptor-targeted therapy of human experimental urinary bladder cancers with cytotoxic LH-RH analog AN-152 [AEZS- 108]

Many bladder cancers progress to invasion with poor prognosis; new therapeutic methods are needed. We developed a cytotoxic LH-RH analog, AN-152 (AEZS-108) containing doxorubicin (DOX), for targeted therapy of cancers expressing LHRH receptors. We investigated the expression of LH-RH receptors in clinical bladder cancers and in HT-1376, J82, RT-4 and HT-1197 human bladder cancer lines. The effect of analog, AN-152, on growth of these tumor lines xenografted into nude mice was analyzed. Using molecular and functional assays, we also evaluated the differences between the effects of AN-152, and DOX alone. We demonstrated the expression of LH-RH receptors on 18 clinical bladder cancers by immunohistochemistry and on four human urinary bladder cancer lines HT-1376, J82, RT-4 and HT-1197 by Western blotting and binding assays. AN-152 powerfully inhibited growth of these bladder cancers in nude mice. AN-152 exerted greater effects than DOX and was less toxic. DOX activated strong multidrug resistance mechanisms in RT-4 and HT-1197 cancers, while AN-152 had no or less such effect. PCR assays and in vitro studies revealed differences in the action of AN-152 and DOX on the expression of genes involved in apoptosis. These results suggest that targeted cytotoxic LH-RH analog, AN-152 (AEZS- 108), should be examined for treatment of patients with LH-RH receptor positive invasive bladder cancers.

A molecular taxonomy for urothelial carcinoma

PURPOSE

Even though urothelial cancer is the fourth most common tumor type among males, progress in treatment has been scarce. A problem in day-to-day clinical practice is that precise assessment of individual tumors is still fairly uncertain; consequently efforts have been undertaken to complement tumor evaluation with molecular biomarkers. An extension of this approach would be to base tumor classification primarily on molecular features. Here, we present a molecular taxonomy for urothelial carcinoma based on integrated genomics.

EXPERIMENTAL DESIGN

We use gene expression profiles from 308 tumor cases to define five major urothelial carcinoma subtypes: urobasal A, genomically unstable, urobasal B, squamous cell carcinoma like, and an infiltrated class of tumors. Tumor subtypes were validated in three independent publically available data sets. The expression of 11 key genes was validated at the protein level by immunohistochemistry.

RESULTS

The subtypes show distinct clinical outcomes and differ with respect to expression of cell-cycle genes, receptor tyrosine kinases particularly FGFR3, ERBB2, and EGFR, cytokeratins, and cell adhesion genes, as well as with respect to FGFR3, PIK3CA, and TP53 mutation frequency. The molecular subtypes cut across pathologic classification, and class-defining gene signatures show coordinated expression irrespective of pathologic stage and grade, suggesting the molecular phenotypes as intrinsic properties of the tumors. Available data indicate that susceptibility to specific drugs is more likely to be associated with the molecular stratification than with pathologic classification.

CONCLUSIONS

We anticipate that the molecular taxonomy will be useful in future clinical investigations.

Cucurbitacin E Induces G(2)/M Phase Arrest through STAT3/p53/p21 Signaling and Provokes Apoptosis via Fas/CD95 and Mitochondria-Dependent Pathways in Human Bladder Cancer T24 Cells

Cucurbitacin E, a tetracyclic triterpenes compound extracted from cucurbitaceous plants, has been shown to exhibit anticancer and anti-inflammatory activities. The purpose of this study was to elucidate whether cucurbitacin E promotes cell cycle arrest and induces apoptosis in T24 cells and further to explore the underlying molecular mechanisms. The effects of cucurbitacin E on T24 cell's growth and accompanied morphological changes were examined by MTT assay and a phase-contrast microscope. DNA content, mitochondrial membrane potential (ΔΨ_m) and annexin V/PI staining were determined by flow cytometry. The protein levels were measured by Western blotting. Our results demonstrated that cucurbitacin E-induced G₂/M arrest was associated with a marked increase in the levels of p53, p21 and a decrease in phospho-signal transducer and activator of transcription 3 (STAT3), cyclin-dependent kinase 1 (CDK1) and cyclin B. Cucurbitacin E-triggered apoptosis was accompanied with up-regulation of Fas/CD95, truncated BID (t-BID) and a loss of ΔΨ_m, resulting in the releases of cytochrome c, apoptotic protease activating factor 1 (Apaf-1) and apoptosis-inducing factor (AIF), and sequential activation of caspase-8, caspase-9, and caspase-3. Our findings provided the first evidence that STAT3/p53/p21 signaling, Fas/CD95 and mitochondria-dependent pathways play critical roles in cucurbitacin E-induced G₂/M phase arrest and apoptosis of T24 cells.