The Impact of Coilin Nonsynonymous SNP Variants E121K and V145I on Cell Growth and Cajal Body Formation: The First Characterization

A Novel Role for Coilin in Vertebrate Innate Immunity

Coilin is a protein localized in the nucleus, where it plays a role in the assembly of the Cajal Body and is involved in ribonucleoprotein biogenesis. Our recent research has uncovered new roles for coilin, including its involvement in producing microRNAs and in modifying other proteins through phosphorylation and SUMOylation. We also proposed that coilin could respond to stress signals. In plants, coilin has been shown to help regulate immune genes and activate defense mechanisms, especially in response to stress. In this study, we used two vertebrate models to study coilin function: a human primary foreskin fibroblast cell line deficient in coilin through RNA interference and a newly created zebrafish line with a mutation in the coilin gene generated by CRISPR-Cas9. Transcriptomic analysis in these two models of coilin deficiency revealed dysregulation of immunity-related genes in both species. To phenotypically validate the transcriptomic results, we challenged zebrafish coilin mutants with lipopolysaccharide (LPS), which triggers an innate immune response, and identified an attenuated response to LPS in vivo in the zebrafish coilin mutants. Our results support a vital novel function for coilin in vertebrates in regulating the expression of immunity-related genes. Moreover, these findings could lead to more research on how coilin regulates innate immunity in animals and humans.

Coilin Is Not Expressed by Immunohistochemistry in Hodgkin and Diffuse Large B-cell Lymphomas

Coilin is the signature protein of Cajal bodies (CBs), membrane-less organelles probably acting as sites for post-transcriptional RNA modification. Recent data suggest that coilin may be a regulator of the NF-kB activity, and Hodgkin lymphomas are hallmarks of neoplasms with NF-kB dysregulation. To the best of our knowledge, the immunohistochemical expression of coilin has been never investigated in Hodgkin lymphomas. We herein examined, by immunohistochemistry, full tissue sections of 58 classical Hodgkin lymphomas diagnosed in 31 male and 27 female patients and found that none of the cases expressed coilin. We compared these findings with Coilin expression in diffuse large B-cell lymphomas (DLBCL), where the marker was also negative. This finding represents the first data on coilin in lymphomas and prompts further studies to explore this downregulation.

Coilin Affects the Prognosis of Hepatocellular Carcinoma Through Cell Cycle and Apoptosis

Purpose

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality with a challenging prognosis. HCC lacks effective prognostic biomarkers. We investigated the diagnostic and prognostic value of COIL expression in HCC.

Patients and Methods

This study evaluated the expression and prognostic significance of COIL using data from the TCGA and local hospital samples, with 374 and 118 liver cancer patients in the TCGA database and local hospital, respectively. The techniques include bioinformatics analysis, qRT-PCR, immunohistochemistry (IHC), and in vitro cell experiments, which encompass CCK-8 assays, wound healing assays, and Transwell invasion assays. The relationship between COIL expression and clinical outcomes was assessed, and COIL's biological function in HCC was investigated through cellular assays.

Results

Analysis of cell lines and HCC tissue samples revealed that COIL mRNA or protein expression levels were significantly higher in HCC cell lines/tissues compared to normal liver cells/tissues. Univariate and multivariate analyses indicated that COIL is an independent prognostic factor for overall survival (OS) in HCC. Additionally, 14% of HCC patients had alterations in the COIL gene, and patients with COIL gene alterations had significantly lower OS (p<0.001) and disease-free survival (DFS) (p<0.001) compared to those without gene alterations. Knockdown of COIL expression inhibited the proliferation, migration, and invasion of Hep3B, HepG2, and Huh7. Compared to the control group, COIL knockdown cells showed a marked reduction in CDC25C and CCNB1 protein levels, suggesting that COIL knockdown leads to G2/M phase cell cycle arrest. After COIL knockdown, caspase-3 and BCL-2 protein levels were downregulated, while cleaved caspase and BAX protein levels were upregulated, indicating that COIL knockdown promotes apoptosis in liver cancer cells.

Conclusion

COIL is an independent predictor of prognosis. COIL's association with poor OS and its role in enhancing cancer cell proliferation and invasion highlight its potential as a therapeutic target.

Pseudogenes and Liquid Phase Separation in Epigenetic Expression

Pseudogenes have been considered as non-functional genes. However, peptides and long non-coding RNAs produced by pseudogenes are expressed in different tumors. Moreover, the dysregulation of pseudogenes is associated with cancer, and their expressions are higher in tumors compared to normal tissues. Recent studies show that pseudogenes can influence the liquid phase condensates formation. Liquid phase separation involves regulating different epigenetic stages, including transcription, chromatin organization, 3D DNA structure, splicing, and post-transcription modifications like m⁶A. Several membrane-less organelles, formed through the liquid phase separate, are also involved in the epigenetic regulation, and their defects are associated with cancer development. However, the association between pseudogenes and liquid phase separation remains unrevealed. The current study sought to investigate the relationship between pseudogenes and liquid phase separation in cancer development, as well as their therapeutic implications.

EZH2 Mediates Proliferation, Migration, and Invasion Promoted by Estradiol in Human Glioblastoma Cells

Glioblastomas (GBM) are the most frequent and aggressive brain tumors. 17β-estradiol (E2) increases proliferation, migration, and invasion of human GBM cells; however underlying mechanisms are no fully understood. Zeste 2 Enhancer Homologous enzyme (EZH2) is a methyltransferase part of Polycomb 2 repressor complex (PRC2). In GBM, EZH2 is overexpressed and involved in the cell cycle, migration, and invasion processes. We studied the role of EZH2 in the pro-oncogenic actions of E2 in human GBM cells. EZH2 gene silencing and pharmacological inhibition of EZH2 blocked proliferation, migration, and invasion of GBM cells induced by E2. We identified in silico additional putative estrogen response elements (EREs) at the EZH2 promoter, but E2 did not modify EZH2 expression. In silico analysis also revealed that among human GBM samples, EZH2 expression was homogeneous; in contrast, the heterogeneous expression of estrogen receptors (ERs) allowed the classification of the samples into groups. Even in the GBM cluster with high expression of ERs and those of their target genes, the expression of PCR2 target genes did not change. Overall, our data suggest that in GBM cells, pro-oncogenic actions of E2 are mediated by EZH2, without changes in EZH2 expression and by mechanisms that appear to be unrelated to the transcriptional activity of ERs.

The Impact of ZIP8 Disease-Associated Variants G38R, C113S, G204C, and S335T on Selenium and Cadmium Accumulations: The First Characterization

The metal cation symporter ZIP8 (SLC39A8) is a transmembrane protein that imports the essential micronutrients iron, manganese, and zinc, as well as heavy toxic metal cadmium (Cd). It has been recently suggested that selenium (Se), another essential micronutrient that has long been known for its role in human health and cancer risk, may also be transported by the ZIP8 protein. Several mutations in the ZIP8 gene are associated with the aberrant ion homeostasis of cells and can lead to human diseases. However, the intricate relationships between ZIP8 mutations, cellular Se homeostasis, and human diseases (including cancers and illnesses associated with Cd exposure) have not been explored. To further verify if ZIP8 is involved in cellular Se transportation, we first knockout (KO) the endogenous expression of ZIP8 in the HeLa cells using the CRISPR/Cas9 system. The elimination of ZIP8 expression was examined by PCR, DNA sequencing, immunoblot, and immunofluorescence analyses. Inductively coupled plasma mass spectrometry indicated that reduced uptake of Se, along with other micronutrients and Cd, was observed in the ZIP8-KO cells. In contrast, when ZIP8 was overexpressed, increased Se uptake could be detected in the ZIP8-overexpressing cells. Additionally, we found that ZIP8 with disease-associated single-point mutations G38R, G204C, and S335T, but not C113S, showed reduced Se transport ability. We then evaluated the potential of Se on Cd cytotoxicity prevention and therapy of cancers. Results indicated that Se could suppress Cd-induced cytotoxicity via decreasing the intracellular Cd transported by ZIP8, and Se exhibited excellent anticancer activity against not all but only selected cancer cell lines, under restricted experimental conditions. Moreover, clinical-based bioinformatic analyses revealed that up-regulated ZIP8 gene expression was common across multiple cancer types, and selenoproteins that were significantly co-expressed with ZIP8 in these cancers had been identified. Taken together, this study concludes that ZIP8 is an important protein in modulating cellular Se levels and provides insights into the roles of ZIP8 and Se in disease prevention and therapy.