The Eyes Absent Proteins: Unusual HAD Family Tyrosine Phosphatases

Establishment of glioma prognosis nomogram based on the function of meox1 in promoting the progression of cancer

Background

Gliomas stand out as highly predominant malignant nervous tumors and are linked to adverse treatment outcomes and short survival periods. Current treatment options are limited, emphasizing the need to identify effective therapeutic targets. The heterogeneity of tumors necessitates a personalized treatment approach with an effective grouping system. Meox1 has been implicated in promoting tumor progression in diverse cancers; nonetheless, its role in gliomas remains unelucidated.

Material/methods

Utilized immunohistochemistry to assess the expression of Meox1 protein in glioma tissues. Proliferation and invasion assays were conducted on wild-type and meox1-overexpressed glioma cells using the CCK8 and Transwell assays, respectively. The expression levels of meox1 and its related genes in gliomas were obtained from Chinese Glioma Genome Atlas (CGGA), along with the corresponding patient survival periods. LASSO regression modeling was employed to construct a scoring system for patients with gliomas, categorizing them into high-/low-risk groups. Additionally, a nomogram for predicting the survival period of patients with glioma was developed using multivariate logistic analysis.

Results

We attempted, for the first time, to demonstrate heightened expression of Meox1 in glioma tumor tissues, correlating with significantly increased invasion and proliferation abilities of glioma cells following meox1 overexpression. The scoring system effectively stratified patients with glioma into high-/low-risk groups, revealing differences in the survival period and immunotherapy efficacy between the two groups. The integration of this scoring system with other clinical indicators yielded a nomogram capable of effectively predicting the survival period of individuals with gliomas.

Conclusions

Our study established a stratified investigation system based on the levels of meox1 and its related genes, providing a novel, cost-effective model for facilitating the prognosis prediction of individuals with glioma.

A Benzarone Derivative Inhibits EYA to Suppress Tumor Growth in SHH Medulloblastoma

Medulloblastoma is one of the most common malignant brain tumors of children, and 30% of medulloblastomas are driven by gain-of-function genetic lesions in the Sonic Hedgehog (SHH) signaling pathway. EYA1, a haloacid dehalogenase phosphatase and transcription factor, is critical for tumorigenesis and proliferation of SHH medulloblastoma (SHH-MB). Benzarone and benzbromarone have been identified as allosteric inhibitors of EYA proteins. Using benzarone as a point of departure, we developed a panel of 35 derivatives and tested them in SHH-MB. Among these compounds, DS-1-38 functioned as an EYA antagonist and opposed SHH signaling. DS-1-38 inhibited SHH-MB growth in vitro and in vivo, showed excellent brain penetrance, and increased the lifespan of genetically engineered mice predisposed to fatal SHH-MB. These data suggest that EYA inhibitors represent promising therapies for pediatric SHH-MB.

SIGNIFICANCE

Development of a benzarone derivative that inhibits EYA1 and impedes the growth of SHH medulloblastoma provides an avenue for improving treatment of this malignant pediatric brain cancer.

RBFOX2 regulated EYA3 isoforms partner with SIX4 or ZBTB1 to control transcription during myogenesis

Alternative splicing is a prevalent gene-regulatory mechanism, with over 95% of multi-exon human genes estimated to be alternatively spliced. Here, we describe a tissue-specific, developmentally regulated, highly conserved, and disease-associated alternative splicing event in exon 7 of the eyes absent homolog 3 (Eya3) gene. We discovered that EYA3 expression is vital to the proliferation and differentiation of myoblasts. Genome-wide transcriptomic analysis and mass spectrometry-based proteomic studies identified SIX homeobox 4 (SIX4) and zinc finger and BTB-domain containing 1 (ZBTB1), as major transcription factors that interact with EYA3 to dictate gene expression. EYA3 isoforms differentially regulate transcription, indicating that splicing aids in temporal control of gene expression during muscle cell differentiation. Finally, we identified RNA-binding fox-1 homolog 2 (RBFOX2) as the main regulator of EYA3 splicing. Together, our findings illustrate the interplay between alternative splicing and transcription during myogenesis.

Dephosphorylation of Six2Y129 protects tyrosine hydroxylase-positive cells in SNpc by regulating TEA domain 1 expression

Parkinson's disease (PD) is a neurodegenerative disease characterized by selective loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). We recently reported that Six2 could reverse the degeneration of DA neurons in a dephosphorylation state. Here we further identified that Eya1 was the phosphatase of Six2 that could dephosphorylate the tyrosine 129 (Y129) site by forming a complex with Six2 in damaged DA cells. Dephosphorylated Six2 then translocates from the cytoplasm to the nucleus. Using ChIP-qPCR and dual luciferase assay, we found that dephosphorylated Six2 down-regulates TEA domain1 (Tead1) expression, thus inhibiting 6-hydroxydopamine (6-OHDA)-induced apoptosis in DA cells. Furthermore, we showed Six2Y129F/Tead1 signaling could protect against the loss of SNpc tyrosine hydroxylase-positive (TH+) cells and improve motor function in PD model rats. Our results demonstrate a dephosphorylation-dependent mechanism of Six2 that restores the degeneration of DA neurons, which could represent a potential therapeutic target for PD.

Delineating the tumour-regulatory roles of EYA4

Eyes absent homolog 4 (EYA4) is a protein that regulates many vital cellular processes and organogenesis pathways. It possesses phosphatase, hydrolase, and transcriptional activation functions. Mutations in the Eya4 gene can cause sensorineural hearing loss and heart disease. In most non-nervous system cancers such as those of the gastrointestinal tract (GIT), hematological and respiratory systems, EYA4 acts as a putative tumor suppressor. However, in nervous system tumors such as glioma, astrocytoma, and malignant peripheral nerve sheath tumor (MPNST), it plays a putative tumor-promoting role. EYA4 interacts with various signaling proteins of the PI3K/AKT, JNK/cJUN, Wnt/GSK-3β, and cell cycle pathways to exert its tumor-promoting or tumor-suppressing effect. The tissue expression level and methylation profiles of Eya4 can help predict the prognosis and anti-cancer treatment response among cancer patients. Targeting and altering Eya4 expression and activity could be a potential therapeutic strategy to suppress carcinogenesis. In conclusion, EYA4 may have both putative tumor-promoting and tumor-suppressing roles in different human cancers and has the potential to serve as a prognostic biomarker and therapeutic agent in various cancer types.

Targeting protein phosphatases in cancer immunotherapy and autoimmune disorders

Protein phosphatases act as key regulators of multiple important cellular processes and are attractive therapeutic targets for various diseases. Although extensive effort has been dedicated to phosphatase-targeted drug discovery, early expeditions for competitive phosphatase inhibitors were plagued by druggability issues, leading to the stigmatization of phosphatases as difficult targets. Despite challenges, persistent efforts have led to the identification of several drug-like, non-competitive modulators of some of these enzymes - including SH2 domain-containing protein tyrosine phosphatase 2, protein tyrosine phosphatase 1B, vascular endothelial protein tyrosine phosphatase and protein phosphatase 1 - reigniting interest in therapeutic targeting of phosphatases. Here, we discuss recent progress in phosphatase drug discovery, with emphasis on the development of selective modulators that exhibit biological activity. The roles and regulation of protein phosphatases in immune cells and their potential as powerful targets for immuno-oncology and autoimmunity indications are assessed.

Friend or foe? Unraveling the complex roles of protein tyrosine phosphatases in cardiac disease and development

Regulation of protein tyrosine phosphorylation is critical for most, if not all, fundamental cellular processes. However, we still do not fully understand the complex and tissue-specific roles of protein tyrosine phosphatases in the normal heart or in cardiac pathology. This review compares and contrasts the various roles of protein tyrosine phosphatases known to date in the context of cardiac disease and development. In particular, it will be considered how specific protein tyrosine phosphatases control cardiac hypertrophy and cardiomyocyte contractility, how protein tyrosine phosphatases contribute to or ameliorate injury induced by ischaemia / reperfusion or hypoxia / reoxygenation, and how protein tyrosine phosphatases are involved in normal heart development and congenital heart disease. This review delves into the newest developments and current challenges in the field, and highlights knowledge gaps and emerging opportunities for future research.

Otic Neurogenesis in Xenopus laevis: Proliferation, Differentiation, and the Role of Eya1

Using immunostaining and confocal microscopy, we here provide the first detailed description of otic neurogenesis in Xenopus laevis. We show that the otic vesicle comprises a pseudostratified epithelium with apicobasal polarity (apical enrichment of Par3, aPKC, phosphorylated Myosin light chain, N-cadherin) and interkinetic nuclear migration (apical localization of mitotic, pH3-positive cells). A Sox3-immunopositive neurosensory area in the ventromedial otic vesicle gives rise to neuroblasts, which delaminate through breaches in the basal lamina between stages 26/27 and 39. Delaminated cells congregate to form the vestibulocochlear ganglion, whose peripheral cells continue to proliferate (as judged by EdU incorporation), while central cells differentiate into Islet1/2-immunopositive neurons from stage 29 on and send out neurites at stage 31. The central part of the neurosensory area retains Sox3 but stops proliferating from stage 33, forming the first sensory areas (utricular/saccular maculae). The phosphatase and transcriptional coactivator Eya1 has previously been shown to play a central role for otic neurogenesis but the underlying mechanism is poorly understood. Using an antibody specifically raised against Xenopus Eya1, we characterize the subcellular localization of Eya1 proteins, their levels of expression as well as their distribution in relation to progenitor and neuronal differentiation markers during otic neurogenesis. We show that Eya1 protein localizes to both nuclei and cytoplasm in the otic epithelium, with levels of nuclear Eya1 declining in differentiating (Islet1/2+) vestibulocochlear ganglion neurons and in the developing sensory areas. Morpholino-based knockdown of Eya1 leads to reduction of proliferating, Sox3- and Islet1/2-immunopositive cells, redistribution of cell polarity proteins and loss of N-cadherin suggesting that Eya1 is required for maintenance of epithelial cells with apicobasal polarity, progenitor proliferation and neuronal differentiation during otic neurogenesis.

Eya1 protein distribution during embryonic development of Xenopus laevis

Eya1 and other Eya proteins are important regulators of progenitor proliferation, cell differentiation and morphogenesis in all three germ layers. At present, most of our knowledge of Eya1 distribution is based on in situ hybridization for Eya1 mRNA. However, to begin to dissect the mechanisms underlying Eya1 functions, we need a better understanding of the spatiotemporal distribution of Eya1 proteins during embryonic development, their subcellular localization and their levels of expression in various tissues. Here we report the localization of Eya1 protein throughout embryonic development from neural plate stages to tadpole stages of Xenopus laevis using a specific antibody for Xenopus Eya1. Our study confirms the expression of Eya1 protein in cranial placodes, placodally derived sensory primordia (olfactory epithelium, otic vesicle, lateral line primordia) and cranial ganglia, as well as in somites, secondary heart field and pharyngeal endoderm. In addition, we report here a novel expression of Eya1 proteins in scattered epidermal cells in Xenopus. Our findings also reveal that, while being predominantly expressed in nuclei in most expression domains, Eya1 protein is also localized to the cytoplasm, in particular in the early preplacodal ectoderm, some placode-derived ganglia and a subset of epidermal cells. While some cytoplasmic roles of Eya1 have been previously described in other contexts, the functions of cytoplasmic Eya1 in the preplacodal ectoderm, cranial ganglia and epidermal cells remain to be investigated.

Assessment of Antidiabetic Activity of the Shikonin by Allosteric Inhibition of Protein-Tyrosine Phosphatase 1B (PTP1B) Using State of Art: An In Silico and In Vitro Tactics

Diabetes mellitus is a multifactorial disease that affects both developing and developed countries and is a major public health concern. Many synthetic drugs are available in the market, which counteracts the associated pathologies. However, due to the propensity of side effects, there is an unmet need for the investigation of safe and effective drugs. This research aims to find a novel phytoconstituent having diminished action on blood glucose levels with the least side effects. Shikonin is a naturally occurring naphthoquinone dying pigment obtained by the roots of the Boraginaceae family. Besides its use as pigments, it can be used as an antimicrobial, anti-inflammatory, and anti-tumor agent. This research aimed to hypothesize the physicochemical and phytochemical properties of Shikonin's in silico interaction with protein tyrosine phosphate 1B, as well as it's in vitro studies, in order to determine its potential anti-diabetic impact. To do so, molecular docking experiments with target proteins were conducted to assess their anti-diabetic ability. Analyzing associations with corresponding amino acids revealed the significant molecular interactions between Shikonin and diabetes-related target proteins. In silico pharmacokinetics and toxicity profile of Shikonin using ADMET Descriptor, Toxicity Prediction, and Calculate Molecular Properties tools from Biovia Discovery Studio v4.5. Filter by Lipinski and Veber Rule's module from Biovia Discovery Studio v4.5 was applied to assess the drug-likeness of Shikonin. The in vitro studies exposed that Shikonin shows an inhibitory potential against the PTP1B with an IC50 value of 15.51 µM. The kinetics studies revealed that it has a competitive inhibitory effect (Ki = 7.5 M) on the enzyme system, which could be useful in the production of preventive and therapeutic agents. The findings of this research suggested that the Shikonin could be used as an anti-diabetic agent and can be used as a novel source for drug delivery.