The role of E3 ubiquitin ligase WWP2 and the regulation of PARP1 by ubiquitinated degradation in acute lymphoblastic leukemia

Apigenin promotes cell death in NCI-H23 cells by upregulation of PTEN: potential involvement of the binding of apigenin with WWP2 protein

The tumour suppressor protein PTEN is often down-regulated in non-small cell lung cancer. A major protein promoting the lowering of the PTEN protein is WWP2. Polyphenols have been shown to promote the expression of tumour suppressor genes like PTEN. We carry out the study to check for the ability of apigenin to bind with the WWP2 protein using in-silico investigation comprising docking and simulation. We checked for the cytotoxic effect of apigenin upon the non-small cell lung cancer cell line NCI-H23. We checked the PTEN expression status at the gene and protein levels. The expression levels of the apoptotic regulators BCL2, BAX and CASPASE3 genes along with the activity levels of the caspase-3 protein were checked. The ultrastructure of the cells was analysed. Our Autodock analysis showed that apigenin bound favourably with the WWP2 protein. Molecular dynamics simulation revealed that apigenin increased the parameters of RMSD, Rg and SASA when bound with the WWP2 protein. The protein-ligand complex had hydrogen bonding and majorly van der Wal's interactions. PCA analysis revealed greater fluctuations in the apigenin-bound state of the protein. The mutant form of the WWP2 revealed similar results in the presence of apigenin. Apigenin showed efficacy against the NCI-H23 cell line and promoted PTEN protein levels, lowered BCL2 gene expression and up-regulated BAX and CASPASE3 gene expression. Increased caspase-3 activity and ultra-structural analysis revealed the occurrence of apoptosis. Thus the binding of apigenin with WWP2 could promote PTEN protein levels and lead to apoptotic activity in NCI-H23 cells.Communicated by Ramaswamy H. Sarma.

E3 ubiquitin ligase WWP2 as a promising therapeutic target for diverse human diseases

Mammalian E3 ubiquitin ligases have emerged in recent years as critical regulators of cellular homeostasis due to their roles in targeting substrate proteins for ubiquitination and triggering subsequent downstream signals. In this review, we describe the multiple roles of WWP2, an E3 ubiquitin ligase with unique and important functions in regulating a wide range of biological processes, including DNA repair, gene expression, signal transduction, and cell-fate decisions. As such, WWP2 has evolved to play a key role in normal physiology and diseases, such as tumorigenesis, skeletal development and diseases, immune regulation, cardiovascular disease, and others. We attempt to provide an overview of the biochemical, physiological, and pathophysiological roles of WWP2, as well as open questions for future research, particularly in the context of putative therapeutic opportunities.

WWP2 binds to NKRF, enhances the NF-κB signaling, and promotes malignant phenotypes of acute myeloid leukemia cells

Acute myeloid leukemia (AML) is one of the hematological malignancies with a high recurrence rate. WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) is identified as a pivotal regulator of tumor progression. This study aimed to assess the possible role of WWP2 in AML. Analysis of the GEPIA database indicated an elevated WWP2 expression in AML. We established stable WWP2-overexpressed or WWP2-silenced cells using lentivirus loaded with cDNA encoding WWP2 mRNA or shRNA targeting WWP2. Notably, WWP2 overexpression facilitated cell proliferation and cell cycle progression, which was manifested as the increase of colony formation number, S-phase percentage and cell cycle related protein levels. As observed, WWP2 knockdown presented opposite effects, leading to inhibition of tumorigenicity. Strikingly, WWP2 knockdown induced apoptosis, accompanied by upregulation of pro-apoptosis proteins cleaved caspase-9, Bax and cleaved caspase-3 and downregulation of anti-apoptosis protein Bcl-2. Functionally, we further confirmed that WWP2 overexpression enhanced the NF-κB signaling and upregulated the levels of downstream genes, which may contribute to aggravating the development of AML. More importantly, by co-immunoprecipitation assay, we verified that WWP2 bound to NF-κB-repressing factor (NKRF) and promoted NKRF ubiquitylation. Dramatically, NKRF overexpression abolished the role of WWP2 in facilitating the process of AML. Overall, our observations confirm that WWP2 exerts a critical role in the tumorigenicity of AML, and NKRF is regarded as an essential factor in the WWP2-mediated AML progression. WWP2 may be proposed as a promising target of AML.

E3 ubiquitin ligases in lung cancer: Emerging insights and therapeutic opportunities

Aim In this review, we have attempted to provide the readers with an updated account of the role of a family of proteins known as E3 ligases in different aspects of lung cancer progression, along with insights into the deregulation of expression of these proteins during lung cancer. A detailed account of the therapeutic strategies involving E3 ligases that have been developed or currently under development has also been provided in this review. MATERIALS AND METHODS: The review article employs extensive literature search, along with differential gene expression analysis of lung cancer associated E3 ligases using the DESeq2 package in R, and the Gene Expression Profiling Interactive Analysis (GEPIA) database (http://gepia.cancer-pku.cn/). Protein expression analysis of CPTAC lung cancer samples was carried out using the UALCAN webtool (https://ualcan.path.uab.edu/index.html). Assessment of patient overall survival (OS) in response to high and low expression of selected E3 ligases was performed using the online Kaplan-Meier plotter (https://kmplot.com/analysis/index.php?p=background). KEY FINDINGS: SIGNIFICANCE: The review provides an in-depth understanding of the role of E3 ligases in lung cancer progression and an up-to-date account of the different therapeutic strategies targeting oncogenic E3 ligases for improved lung cancer management.

The Complex Network of ADP-Ribosylation and DNA Repair: Emerging Insights and Implications for Cancer Therapy

ADP-ribosylation is a post-translational modification of proteins that plays a key role in various cellular processes, including DNA repair. Recently, significant progress has been made in understanding the mechanism and function of ADP-ribosylation in DNA repair. ADP-ribosylation can regulate the recruitment and activity of DNA repair proteins by facilitating protein-protein interactions and regulating protein conformations. Moreover, ADP-ribosylation can influence additional post-translational modifications (PTMs) of proteins involved in DNA repair, such as ubiquitination, methylation, acetylation, phosphorylation, and SUMOylation. The interaction between ADP-ribosylation and these additional PTMs can fine-tune the activity of DNA repair proteins and ensure the proper execution of the DNA repair process. In addition, PARP inhibitors have been developed as a promising cancer therapeutic strategy by exploiting the dependence of certain cancer types on the PARP-mediated DNA repair pathway. In this paper, we review the progress of ADP-ribosylation in DNA repair, discuss the crosstalk of ADP-ribosylation with additional PTMs in DNA repair, and summarize the progress of PARP inhibitors in cancer therapy.

Atorvastatin rescues vascular endothelial injury in hypertension by WWP2-mediated ubiquitination and degradation of ATP5A

As a widely used lipid-lowering drug in clinical practice, atorvastatin is widely recognized for its role in protecting vascular endothelium in the cardiovascular system. However, a clear mechanistic understanding of its action is lacking. Here, we found that atorvastatin counteracted angiotensin II-induced vascular endothelial injury in mice with hypertension. Mechanistically, atorvastatin up-regulated WWP2, a E6AP C-terminus (HECT)-type E3 ubiquitin ligase with an essential role in regulating protein ubiquitination and various biological processes, thereby rescuing vascular endothelial injury. By ubiquitinating ATP5A (ATP synthase mitochondrial F1 complex subunit alpha), WWP2 degraded ATP5A via the proteasome pathway, stabilizing Bcl-2/Bax in the mitochondrial pathway of apoptosis. Moreover, atorvastatin further ameliorated death of vascular endothelial cells and improved vascular endothelial functions under WWP2 overexpression, whereas WWP2 knockout abrogated these beneficial effects of atorvastatin. Furthermore, we generated endothelial cell-specific WWP2 knockout mice, and this WWP2-mediated mechanism was faithfully recapitulated in vivo. Thus, we propose that activation of a WWP2-dependent pathway that is pathologically repressed in damaged vascular endothelium under hypertension is a major mechanism of atorvastatin. Our findings are also pertinent to develop novel therapeutic strategies for vascular endothelial injury-related cardiovascular diseases.