UNC5 dependence receptor family in human cancer: A controllable double-edged sword

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development. Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function. Increasing amounts of evidence highlight several key points: (1) Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer's disease and Parkinson's disease, and potentially, similar alterations occur in humans. (2) Genetic mutations of Netrin-1 receptors increase an individuals' susceptibility to neurodegenerative disorders. (3) Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function. (4) Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers. These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases. Through a comprehensive review of Netrin-1 signaling pathways, our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

Integrative analysis reveals the potential prognostic roles and immunological values of unc-5 netrin receptor A (UNC5A) in glioma

BACKGROUND

UNC5A had been reported to play crucial roles in multiple cancers. However, little was known about the associations among UNC5A and glioma. Therefore, we first combined scRNA-seq, proteomics, as well as bulk RNA-seq in order to investigate UNC5A's functions in gliomas.

METHODS

Online databases provided scRNA-seq, proteomics, as well as bulk RNA-seq data on UNC5A in gliomas. The following procedures were conducted in order: QRT-PCR, Norman chart, gene set enrichment analysis (GSEA), and univariate/multifactor Cox regression analyses. We further explored the associations among UNC5A and tumor immunity.

RESULTS

By comparing gliomas with normal tissues, the TCGA dataset showed a significantly reduced expression of UNC5A, which was also confirmed by GSE50161, GSE4290, and QRT-PCR findings (p < 0.05). In both the TCGA and CGGA datasets, gliomas patients with low-UNC5A expression would have poorer overall survival (OS) prognoses (p < 0.05). ScRNA-seq analysis by the CancerSEA online website presented that UNC5A had a low expression in various glioma clusters and significantly associated with six functional states. Moreover, UNC5A might be a reliable independent biomarker of OS in gliomas patients (p < 0.05). Based on the results of GSEA, UNC5A might be connected to three significant pathways in gliomas. We also successfully created a Norman chart to assess the OS prognoses of these patients. Additionally, in aspects of tumor immunity, the infiltration levels of immune cells in LGG, the immune cell pathways, tumor immune microenvironment, as well as immune checkpoints in both LGG and GBM were revealed to be significantly influenced by UNC5A (p < 0.05).

CONCLUSIONS

UNC5A was found to have prognostic and immunological significance in gliomas, offering patients with gliomas new treatment options.

UNC5C: Novel Gene Associated with Psychiatric Disorders Impacts Dysregulation of Axon Guidance Pathways

The UNC-5 family of netrin receptor genes, predominantly expressed in brain tissues, plays a pivotal role in various neuronal processes. Mutations in genes involved in axon development contribute to a wide spectrum of human diseases, including developmental, neuropsychiatric, and neurodegenerative disorders. The NTN1/DCC signaling pathway, interacting with UNC5C, plays a crucial role in central nervous system axon guidance and has been associated with psychiatric disorders during adolescence in humans. Whole-exome sequencing analysis unveiled two compound heterozygous causative mutations within the UNC5C gene in a patient diagnosed with psychiatric disorders. In silico analysis demonstrated that neither of the observed variants affected the allosteric linkage between UNC5C and NTN1. In fact, these mutations are located within crucial cytoplasmic domains, specifically ZU5 and the region required for the netrin-mediated axon repulsion of neuronal growth cones. These domains play a critical role in forming the supramodular protein structure and directly interact with microtubules, thereby ensuring the functionality of the axon repulsion process. We emphasize that these mutations disrupt the aforementioned processes, thereby associating the UNC5C gene with psychiatric disorders for the first time and expanding the number of genes related to psychiatric disorders. Further research is required to validate the correlation of the UNC5C gene with psychiatric disorders, but we suggest including it in the genetic analysis of patients with psychiatric disorders.

Using Single-Cell RNA Sequencing and MicroRNA Targeting Data to Improve Colorectal Cancer Survival Prediction

Colorectal cancer has proven to be difficult to treat as it is the second leading cause of cancer death for both men and women worldwide. Recent work has shown the importance of microRNA (miRNA) in the progression and metastasis of colorectal cancer. Here, we develop a metric based on miRNA-gene target interactions, previously validated to be associated with colorectal cancer. We use this metric with a regularized Cox model to produce a small set of top-performing genes related to colon cancer. We show that using the miRNA metric and a Cox model led to a meaningful improvement in colon cancer survival prediction and correct patient risk stratification. We show that our approach outperforms existing methods and that the top genes identified by our process are implicated in NOTCH3 signaling and general metabolism pathways, which are essential to colon cancer progression.

A Systematic Analysis of the Role of Unc-5 Netrin Receptor A (UNC5A) in Human Cancers

Unc-5 netrin receptor A (UNC5A), a netrin family receptor, plays a key role in neuronal development and subsequent differentiation. Recently, studies have found that UNC5A plays an important role in multiple cancers, such as bladder cancer, non-small cell lung carcinoma, and colon cancer but its pan-cancer function is largely unknown. Herein, the R software and multiple databases or online websites (The Cancer Genome Atlas (TCGA), The Genotype-Tissue Expression (GTEx), The Tumor Immune Estimation Resource (TIMER), The Gene Set Cancer Analysis (GSCA), Gene Expression Profiling Interactive Analysis (GEPIA), and cBioPortal etc.) were utilized to examine the role of UNC5A in pan-cancer. UNC5A was found to be highly expressed across multiple human cancer tissues and cells, was linked to clinical outcomes of patients, and was a potential pan-cancer biomarker. The mutational landscape of UNC5A exhibited that patients with UNC5A mutations had poorer progress free survival (PFS) in head and neck squamous cell carcinoma (HNSC) and prostate adenocarcinoma (PRAD). Furthermore, UNC5A expression was associated with tumor mutation burden (TMB), neoantigen, tumor microenvironment (TME), tumor microsatellite instability (MSI), immunomodulators, immune infiltration, DNA methylation, immune checkpoint (ICP) genes, and drug responses. Our results suggest the potential of UNC5A as a pan-cancer biomarker and an efficient immunotherapy target, which may also guide drug selection for some specific cancer types in clinical practice.

A Novel 3-Gene Signature for Identifying COVID-19 Patients Based on Bioinformatics and Machine Learning

Although many biomarkers associated with coronavirus disease 2019 (COVID-19) were found, a novel signature relevant to immune cells has not been developed. In this work, the “CIBERSORT” algorithm was used to assess the fraction of immune infiltrating cells in GSE152641 and GSE171110. Key modules associated with important immune cells were selected by the “WGCNA” package. The “GO” enrichment analysis was used to reveal the biological function associated with COVID-19. The “Boruta” algorithm was used to screen candidate genes, and the “LASSO” algorithm was used for collinearity reduction. A novel gene signature was developed based on multivariate logistic regression analysis. Subsequently, M0 macrophages (PRAUC = 0.948 in GSE152641 and PRAUC = 0.981 in GSE171110) and neutrophils (PRAUC = 0.892 in GSE152641 and PRAUC = 0.960 in GSE171110) were considered as important immune cells. Forty-three intersected genes from two modules were selected, which mainly participated in some immune-related activities. Finally, a three-gene signature comprising CLEC4D, DUSP13, and UNC5A that can accurately distinguish COVID-19 patients and healthy controls in three datasets was constructed. The ROCAUC was 0.974 in the training set, 0.946 in the internal test set, and 0.709 in the external test set. In conclusion, we constructed a three-gene signature to identify COVID-19, and CLEC4D, DUSP13, and UNC5A may be potential biomarkers for COVID-19 patients.

PIDD1 in cell cycle control, sterile inflammation and cell death

The death fold domain-containing protein PIDD1 has recently attracted renewed attention as a regulator of the orphan cell death-related protease, Caspase-2. Caspase-2 can activate p53 to promote cell cycle arrest in response to centrosome aberrations, and its activation requires formation of the PIDDosome multi-protein complex containing multimers of PIDD1 and the adapter RAIDD/CRADD at its core. However, PIDD1 appears to be able to engage with multiple client proteins to promote an even broader range of biological responses, such as NF-κB activation, translesion DNA synthesis or cell death. PIDD1 shows features of inteins, a class of self-cleaving proteins, to create different polypeptides from a common precursor protein that allow it to serve these diverse functions. This review summarizes structural information and molecular features as well as recent experimental advances that highlight the potential pathophysiological roles of this unique death fold protein to highlight its drug-target potential.

Promoter methylation-mediated repression of UNC5 receptors and the associated clinical significance in human colorectal cancer

Background

Deregulated methylation of tumor suppressor genes is a hallmark event in colorectal cancer (CRC) carcinogenesis. UNC5 receptors, down-regulated in various human malignancies due to epigenetic alterations, have been proposed as putative tumor suppressor genes. In this study, we focused on the methylation-mediated inhibition of UNC5 receptors and the associated clinical significance in CRC.

Methods

Methylation and expression analysis was performed in TCGA datasets. And the results were confirmed in vitro in CRC cell lines treated with 5-aza-deoxycytidine. Then, the expression and epigenetic alterations of UNC5 receptors were evaluated in clinical specimens. Moreover, the diagnostic and prognostic values of the methylation alterations were also analyzed.

Results

Methylation-mediated repression was observed in UNC5C and UNC5D, but not in UNC5A and UNC5B, which was confirmed in CRC cell lines. Except for UNC5B, significantly elevated methylation was observed in UNC5A, UNC5C, and UNC5D in CRC. The discrimination efficiency of the three receptors was comparable with that of SEPT9. Kaplan–Meier curve survival analysis showed that hypermethylation of UNC5A, UNC5C and UNC5D was associated with poor progression-free and overall survival. Moreover, methylation levels of UNC5C and UNC5D were independent predictors of CRC progression-free (P = 0.001, P = 0.003, respectively) and overall survival (P = 0.008, P = 0.004, respectively).

Conclusions

Hypermethylation of UNC5C and UNC5D mediates the repression and has promising diagnostic and prognostic values in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01211-5.

Dependence receptors: new targets for cancer therapy

Dependence receptors are known to promote survival and positive signaling such as proliferation, migration, and differentiation when activated, but to actively trigger apoptosis when unbound to their ligand. Their abnormal regulation was shown to be an important feature of tumorigenesis, allowing cancer cells to escape apoptosis triggered by these receptors while promoting in parallel major aspects of tumorigenesis such as proliferation, angiogenesis, invasiveness, and chemoresistance. This involvement in multiple cancer hallmarks has raised interest in dependence receptors as targets for cancer therapy. Although additional studies remain necessary to fully understand the complexity of signaling pathways activated by these receptors and to target them efficiently, it is now clear that dependence receptors represent very exciting targets for future cancer treatment. This manuscript reviews current knowledge on the contribution of dependence receptors to cancer and highlights the potential for therapies that activate pro-apoptotic functions of these proteins.