EGR-mediated control of STIM expression and function

NFYA-mediated promotion of castration-resistant prostate cancer progression through EGR4 regulation

This research investigates the intricate involvement of nuclear Transcription Factor Y Subunit Alpha (NFYA) in the advancement of castration-resistant prostate cancer (CRPC) and its consequential impact on early Growth Response 4 (EGR4) expression. NFYA demonstrates a significant elevation in CRPC tissues and cell lines, displaying robust upregulation in metastatic prostate cancer (mPCa) samples, closely associated with the Gleason score. Immunohistochemistry validates heightened nuclear staining of NFYA in CRPC patients, highlighting its crucial role in the progression of advanced prostate cancer. Silencing NFYA through siRNA in androgen-independent cell lines markedly impedes cell growth and migration, emphasizing NFYA's pivotal role in promoting CRPC behavior. RNA-seq analysis identifies EGR4 as a downstream target of NFYA, with both genes consistently upregulated in CRPC. Validating this finding, heightened expression of EGR4 is observed in CRPC samples. In vivo studies utilizing a mouse model demonstrate that NFYA silencing substantially inhibits LNCaP-AI/22RV1shNFYA xenograft tumor growth, accompanied by reduced expression of EGR4 and Ki67. This comprehensive study reveals the multifaceted role of NFYA in CRPC progression, elucidates its downstream impact on EGR4, and underscores the therapeutic potential of targeting NFYA to inhibit CRPC growth in vivo. These findings contribute valuable insights into potential therapeutic strategies for managing CRPC.

Multifaceted control of T cell differentiation by STIM1

In T cells, stromal interaction molecule (STIM) and Orai are dispensable for conventional T cell development, but critical for activation and differentiation. This review focuses on novel STIM-dependent mechanisms for control of Ca2+ signals during T cell activation and its impact on mitochondrial function and transcriptional activation for control of T cell differentiation and function. We highlight areas that require further work including the roles of plasma membrane Ca2+ ATPase (PMCA) and partner of STIM1 (POST) in controlling Orai function. A major knowledge gap also exists regarding the independence of T cell development from STIM and Orai, despite compelling evidence that it requires Ca2+ signals. Resolving these and other outstanding questions ensures that the field will remain active for many years to come.

The Landscape of Early Growth Response Family Members 1-4 in Hepatocellular Carcinoma: Their Biological Roles and Diagnostic Utility

The incidence of hepatocellular carcinoma (HCC), which is one of the most frequent types of cancer seen all over the world, is steadily growing from year to year. EGR genes are members of the early growth response (EGR) gene family. It has been shown that EGR genes play an increasingly essential role in the development of tumors and the progression of numerous malignancies. However, the possible diagnostic and prognostic roles of EGR genes in HCC have only been examined in a limited number of studies. Expression and methylation data on EGR family members were obtained from TCGA datasets. The prognostic values of EGR members were studied. Additionally, the correlations of EGR members with immune cells were assessed through the single-sample gene set enrichment analysis (ssGSEA). In this study, we found that the expression of EGR1, EGR2, EGR3, and EGR4 was distinctly decreased in HCC specimens compared with nontumor specimens. ROC assays confirmed that they have a strong ability in screening HCC specimens from nontumor specimens. According to the findings of Pearson's correlation, EGR1, EGR2, EGR3, and EGR4 were found to have a negative association with the methylation level. Survival study revealed that EGR1, EGR2, and EGR3 were associated with the clinical outcome of HCC patients. Immune cell enrichment analysis demonstrated that the expressions of all EGR members were positively related to the levels of most types of immune cells, such as macrophages, NK cells, B cells, T cells, eosinophils, and CD8 T cells. Overall, the current work demonstrated the expression mode and prognostic value of EGR members in HCC in a comprehensive manner, offering insights for further research of the EGR family as possible clinical biomarkers in HCC.

Distinct structural bases for sequence-specific DNA binding by mammalian BEN domain proteins

The BEN domain is a recently recognized DNA binding module that is present in diverse metazoans and certain viruses. Several BEN domain factors are known as transcriptional repressors, but, overall, relatively little is known of how BEN factors identify their targets in humans. In particular, X-ray structures of BEN domain:DNA complexes are only known for Drosophila factors bearing a single BEN domain, which lack direct vertebrate orthologs. Here, we characterize several mammalian BEN domain (BD) factors, including from two NACC family BTB-BEN proteins and from BEND3, which has four BDs. In vitro selection data revealed sequence-specific binding activities of isolated BEN domains from all of these factors. We conducted detailed functional, genomic, and structural studies of BEND3. We show that BD4 is a major determinant for in vivo association and repression of endogenous BEND3 targets. We obtained a high-resolution structure of BEND3-BD4 bound to its preferred binding site, which reveals how BEND3 identifies cognate DNA targets and shows differences with one of its non-DNA-binding BEN domains (BD1). Finally, comparison with our previous invertebrate BEN structures, along with additional structural predictions using AlphaFold2 and RoseTTAFold, reveal distinct strategies for target DNA recognition by different types of BEN domain proteins. Together, these studies expand the DNA recognition activities of BEN factors and provide structural insights into sequence-specific DNA binding by mammalian BEN proteins.

The Role of Early Growth Response Family Members 1-4 in Prognostic Value of Breast Cancer

Early growth response family members (EGRs), EGR1–4, have increasingly attracted attention in multiple cancers. However, the exact expression patterns and prognostic values of EGRs in the progress of breast cancer (BRCA) remain largely unknown. The mRNA expression and prognostic characteristics of EGRs were examined by the Cancer Genome Atlas (TCGA), Oncomine, and Kaplan-Meier plotter. Enrichment analyses were conducted based on protein-protein interaction (PPI) network. The Tumor Immune Estimation Resource (TIMER) database and MethSurv were further explored. The protein expression of EGR1 in BRCA was measured by western blotting and immunohistochemistry. The migration of mammary epithelial cells was determined by Boyden chamber assay. The transcriptional levels of EGR1/2/3 displayed significantly low expression in BRCA compared with that in normal tissues, while EGR4 was shown adverse expression pattern. Survival analysis revealed upregulated EGR1–4 were remarkably associated with favorable relapse-free survival (RFS). A close correlation with specific tumor-infiltrating immune cells (TIICs) and several CpG sites of EGRs were exhibited. Immunohistochemistry assays showed that the protein expression of EGR1 was remarkably downregulated in BRCA compared with that in paracancerous tissues. The migration of MCF10A mammary epithelial cells was increased after the silence of EGR1 by siRNA transfection. This study provides a novel insight to the role of EGRs in the prognostic value of BRCA.

Tissue-specific transcriptional imprinting and heterogeneity in human innate lymphoid cells revealed by full-length single-cell RNA-sequencing

The impact of the microenvironment on innate lymphoid cell (ILC)-mediated immunity in humans remains largely unknown. Here we used full-length Smart-seq2 single-cell RNA-sequencing to unravel tissue-specific transcriptional profiles and heterogeneity of CD127⁺ ILCs across four human tissues. Correlation analysis identified gene modules characterizing the migratory properties of tonsil and blood ILCs, and signatures of tissue-residency, activation and modified metabolism in colon and lung ILCs. Trajectory analysis revealed potential differentiation pathways from circulating and tissue-resident naïve ILCs to a spectrum of mature ILC subsets. In the lung we identified both CRTH2⁺ and CRTH2^- ILC2 with lung-specific signatures, which could be recapitulated by alarmin-exposure of circulating ILC2. Finally, we describe unique TCR-V(D)J-rearrangement patterns of blood ILC1-like cells, revealing a subset of potentially immature ILCs with TCR-δ rearrangement. Our study provides a useful resource for in-depth understanding of ILC-mediated immunity in humans, with implications for disease.

Ca2+ as a therapeutic target in cancer

Ca2+ is a ubiquitous and dynamic second messenger molecule that is induced by many factors including receptor activation, environmental factors, and voltage, leading to pleiotropic effects on cell function including changes in migration, metabolism and transcription. As such, it is not surprising that aberrant regulation of Ca2+ signals can lead to pathological phenotypes, including cancer progression. However, given the highly context-specific nature of Ca2+-dependent changes in cell function, delineation of its role in cancer has been a challenge. Herein, we discuss the distinct roles of Ca2+ signaling within and between each type of cancer, including consideration of the potential of therapeutic strategies targeting these signaling pathways.

Very Low-Density Lipoproteins of Metabolic Syndrome Modulates STIM1, Suppresses Store-Operated Calcium Entry, and Deranges Myofilament Proteins in Atrial Myocytes

Individuals with metabolic syndrome (MetS) are at high risk for atrial myopathy and atrial fibrillation. Very low-density lipoproteins (VLDLs) of MetS (MetS-VLDLs) are cytotoxic to atrial myocytes in vivo and in vitro. The calcineurin-nuclear factor of activated T-cells (NFAT) pathway, which is regulated by stromal interaction molecule 1 (STIM1)/ calcium release-activated calcium channel protein 1 (Orai1)-mediated store-operated Ca²⁺ entry (SOCE), is a pivotal mediator of adaptive cardiac hypertrophy. We hypothesized that MetS-VLDLs could affect SOCE and the calcineurin-NFAT pathway. Normal-VLDL and MetS-VLDL samples were isolated from the peripheral blood of healthy volunteers and individuals with MetS. VLDLs were applied to HL-1 atrial myocytes for 18 h and were also injected into wild-type C57BL/6 male mouse tails three times per week for six weeks. After the sarcoplasmic reticulum (SR) Ca²⁺ store was depleted, SOCE was triggered upon reperfusion with 1.8 mM of Ca²⁺. SOCE was attenuated by MetS-VLDLs, along with reduced transcriptional and membranous expression of STIM1 (P = 0.025), and enhanced modification of O-GlcNAcylation on STIM1 protein, while Orai1 was unaltered. The nuclear translocation and activity of calcineurin were both reduced (P < 0.05), along with the alteration of myofilament proteins in atrial tissues. These changes were absent in normal-VLDL-treated cells. Our results demonstrated that MetS-VLDLs suppressed SOCE by modulating STIM1 at the transcriptional, translational, and post-translational levels, resulting in the inhibition of the calcineurin-NFAT pathway, which resulted in the alteration of myofilament protein expression and sarcomere derangement in atrial tissues. These findings may help explain atrial myopathy in MetS. We suggest a therapeutic target on VLDLs to prevent atrial fibrillation, especially for individuals with MetS.