PIGU overexpression adds value to TNM staging in the prognostic stratification of patients with hepatocellular carcinoma

Therapeutic and Diagnostic Potential of Folic Acid Receptors and Glycosylphosphatidylinositol (GPI) Transamidase in Prostate Cancer

Due to the proliferation-induced high demand of cancer cells for folic acid (FA), significant overexpression of folate receptors 1 (FR1) is detected in most cancers. To our knowledge, a detailed characterization of FR1 expression and regulation regarding therapeutic and diagnostic feasibilities in prostate cancer (PCa) has not been described. In the present study, cell cultures, as well as tissue sections, were analyzed using Western blot, qRT-PCR and immunofluorescence. In addition, we utilized FA-functionalized lipoplexes to characterize the potential of FR1-targeted delivery into PCa cells. Interestingly, we detected a high level of FR1-mRNA in healthy prostate epithelial cells and healthy prostate tissue. However, we were able to show that PCa cells in vitro and PCa tissue showed a massively enhanced FR1 membrane localization where the receptor can finally gain its function. We were able to link these changes to the overexpression of GPI-transamidase (GPI-T) by image analysis. PCa cells in vitro and PCa tissue show the strongest overexpression of GPI-T and thereby induce FR1 membrane localization. Finally, we utilized FA-functionalized lipoplexes to selectively transfer pDNA into PCa cells and demonstrate the therapeutic potential of FR1. Thus, FR1 represents a very promising candidate for targeted therapeutic transfer pathways in PCa and in combination with GPI-T, may provide predictive imaging in addition to established diagnostics.

Role of PIGM and PIGX in glycosylphosphatidylinositol biosynthesis and human health (Review)

Glycosylphosphatidylinositol-glycan (GPI) is an anchor to specific cell surface proteins known as GPI-anchored proteins (APs) that are localized in lipid rafts and may act as cell co-receptors, enzymes and adhesion molecules. The present review investigated the significance of GPI biosynthesis class phosphatidylinositol-glycan (PIG)M and PIGX in GPI synthesis and their implications in human health conditions. PIGM encodes GPI-mannosyltransferase I (MT-I) enzyme that adds the first mannose to the GPI core structure. PIGX encodes the regulatory subunit of GPI-MT-I. The present review summarizes characteristics of the coding sequences of PIGM and PIGX, and their expression in humans, as well as the relevance of GPI-MT-I and the regulatory subunit in maintaining the presence of GPI-APs on the cell surface and their secretion. In addition, the association of PIGM mutations with paroxysmal nocturnal hemoglobinuria and certain types of GPI-deficiency disease and the altered expression of PIGM and PIGX in cancer were also reviewed. In addition, their interaction with other proteins was described, suggesting a complex role in cell biology. PIGM and PIGX are critical genes for GPI synthesis. Understanding gene and protein regulation may provide valuable insights into the role of GPI-APs in cellular processes.

PIGT promotes cell growth, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking

BACKGROUND

Bladder cancer is very common worldwide. PIGT is a subunit of the glycosylphosphatidylinositol transamidase which involves in tumorigenesis and invasiveness. m6A modification of mRNA has been linked to cell proliferation, tumor progression and other biological events. However, how PIGT is regulated and what is the function of PIGT in bladder cancer remains to be elucidated.

METHODS

PIGT was silenced or overexpressed to study its role in regulating bladder cancer. Cell proliferation and invasion were examined with the Cell Counting Kit-8, colony formation and Transwell assay, respectively. Cellular oxygen consumption rates or extracellular acidification rates were detected by a XF24 Analyzer. Quantitative RT-PCR and immunoblots were performed to detect mRNA and protein levels.

RESULTS

PIGT was overexpressed in bladder cancer. Silencing PIGT inhibited cell proliferation, oxidative phosphorylation, and glycolysis. Overexpressing PIGT promoted cell proliferation, oxidative phosphorylation, glycolysis in vitro and tumor metastasis in vivo by activating glucose transporter 1 (GLUT1). PIGT also promoted GLUT1 glycosylation and membrane trafficking. Wilms' tumor 1-associated protein (WTAP) mediated PIGT m6A modification, and m6A reader, insulin-like growth factor 2 mRNA-binding protein (IGF2BP2), binds to the methylated PIGT to promote the stability of PIGT, leading to up-regulation of PIGT.

CONCLUSION

WTAP mediates PIGT m6A modification to increase the stability of PIGT via the IGF2BP2, which enhances cell proliferation, glycolysis, and metastasis in bladder cancer by modulating GLUT1 glycosylation and membrane trafficking.

The Prognostic Significance and Potential Mechanism of Ferroptosis-Related Genes in Hepatocellular Carcinoma

Ferroptosis exerts a pivotal role in the formation and dissemination processes of hepatocellular carcinoma (HCC). The heterogeneity of ferroptosis and the link between ferroptosis and immune responses have remained elusive. Based on ferroptosis-related genes (FRGs) and HCC patients from The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO) cohorts, we comprehensively explored the heterogeneous ferroptosis subtypes. The genetic alterations, consensus clustering and survival analysis, immune infiltration, pathway enrichment analysis, integrated signature development, and nomogram building were further investigated. Kaplan-Meier plotter confirmed statistically differential probabilities of survival among the three subclusters. Immune infiltration analysis showed there were clear differences among the types of immune cell infiltration, the expression of PD-L1, and the distribution of TP53 mutations among the three clusters. Univariate Cox regression analysis, random survival forest, and multivariate Cox analysis were used to identify the prognostic integrated signature, including MED8, PIGU, PPM1G, RAN, and SNRPB. Kaplan-Meier analysis and time-dependent receiver operating characteristic (ROC) curves revealed the satisfactory predictive potential of the five-gene model. Subsequently, a nomogram was established, which combined the signature with clinical factors. The nomogram including the ferroptosis-based signature was conducted and showed some clinical net benefits. These results facilitated an understanding of ferroptosis and immune responses for HCC.

Identification of a Prognostic Index Based on a Metabolic-Genomic Landscape Analysis of Hepatocellular Carcinoma (HCC)

Background

Metabolic disorders have attracted increasing attention from scientists who conduct research on various tumours, especially hepatocellular carcinoma (HCC). The purpose of this study was to assess the prognostic significance of metabolism in HCC.

Methods

The expression profiles of metabolism-related genes (MRGs) of 349 surviving HCC patients were extracted from The Cancer Genome Atlas (TCGA) database. Subsequently, a series of biomedical computational algorithms were used to identify a seven-MRG signature as a prognostic model. GSEA indicated the function and pathway enrichment of these MRGs. Then, drug sensitivity analysis was used to identify the hub gene, which was tested using IHC staining.

Results

A total of 420 differential MRGs and 116 differentially expressed transcription factors (TFs) were identified in HCC patients based on data from the TCGA database. The GO and KEGG enrichment analyses indicated that metabolic disturbance might be involved in the development of HCC. LASSO regression analysis was used to construct a seven-MRG signature (DHDH, ENO1, G6PD, LPCAT1, PDE6D, PIGU and PPAT) that could predict the prognosis of HCC patients. GSEA revealed the functional and pathway enrichment of these seven MRGs. Then, drug sensitivity analysis indicated that G6PD might play a key role in the prognosis of HCC by promoting chemoresistance. Finally, we used IHC staining to demonstrate the relationship between G6PD expression levels and clinical parameters in HCC patients.

Conclusion

The results of this study provide a potential method for predicting the prognosis of HCC patients and avenues for further studies of HCC metabolism. Moreover, the function of G6PD may play a key role in the development and progression of HCC.

PIGU promotes hepatocellular carcinoma progression through activating NF-κB pathway and increasing immune escape

Hepatocellular carcinoma (HCC) is the sixth most common malignancy and has the third highest mortality rate among all tumors. Previous studies found that phosphatidylinositol glycan anchor biosynthesis class U (PIGU) was highly expressed in hepatocellular carcinoma (HCC), while the function of PIGU in HCC remains unknown. Here, we deeply investigated this issue. The expression levels of PIGU in HCC cells were measured by Western blotting. The functions of PIGU in HCC cells were assessed in vitro, followed by assessing the nuclear factor-kappa B (NF-κB) pathway-related protein levels. The xenograft mouse models were conducted to investigate the effects of PIGU in vivo. Moreover, the effects of PIGU downregulation on natural killer (NK)-92 cell-mediated cell killing were detected. The results showed that PIGU was highly expressed in HCC cells compared with normal liver cells. Functional studies showed that PIGU promoted viability, cell cycle progression, migration, and invasion and suppressed apoptosis in HCC cells. Mechanism studies indicated that PIGU silencing blocked the NF-κB pathway and the blockade of the NF-κB pathway reversed the effects of PIGU overexpression on HCC cell function, including cell viability, migration, invasion, and apoptosis. In vivo studies further verified the effects of PIGU on HCC cell function, and demonstrated that PIGU knockdown suppressed tumorigenesis. Additionally, we proved that PIGU downregulation significantly enhanced the sensitivity of HCC cells to NK-92 cell cytolysis. Collectively, PIGU may promote HCC progression through activating the NF-κB pathway and promoting immune escape, indicating that PIGU may serve as a promising therapeutic target for HCC treatment.

NT5DC2 is a novel prognostic marker in human hepatocellular carcinoma

Reliable biomarkers for the prognosis of hepatocellular carcinoma (HCC) are rare, and novel biomarkers are required for the appropriate management of HCC. 5′-Nucleotidase domain containing 2 (NT5DC2) acts as an oncogene in various tumors, but its functions as a biomarker have not been confirmed. Therefore, the present study aimed to resolve these functions by analyzing the prognostic value of NT5DC2 in patients with HCC. A tissue microarray (TMA) was prepared and NT5DC2 expression was measured via IHC staining in TMA dots. The liver cancer (LIHC) cohort in The Cancer Genome Atlas (TCGA) was enrolled as a secondary cohort. Kaplan-Meier survival analyses and Cox regression models were used for assessment of the prognostic value of NT5DC2. Gene set enrichment analysis (GSEA) was performed in TCGA LIHC cohort. A total of 134 patients with HCC were retrospectively enrolled in the Peking Union Medical College Hospital cohort and clinical data were collected. A total of 359 patients with HCC in TCGA were enrolled as TCGA cohort. NT5DC2 was used as an indicator of overall survival (OS) and relapse-free survival (RFS) in multiple cohorts. In the multivariate Cox regression model, NT5DC2 upregulation was an independent prognostic factor of OS in both cohorts. GSEA indicated the enrichment of a series of survival- and metastasis-related gene-sets, such as LEE_LIVER_CANCER_SURVIVAL_UP and LIAO_METASTASIS. Collectively, it was suggested that NT5DC2 upregulation was associated with poor OS and RFS in HCC, and was a potential predictive marker for HCC stratification.

Identification of PIGU as the Hub Gene Associated with KRAS Mutation in Colorectal Cancer by Coexpression Analysis

Colorectal cancer (CRC) patients with KRAS mutation are refractory and usually have poor prognosis. We aimed to identify the hub gene associated with KRAS mutant CRCs. Weighted gene coexpression network analysis (WGCNA) was used to calculate the key module and the hub genes in GSE39582. Combined with the protein-protein interaction (PPI) network and survival analysis, the real hub gene was identified and further validated. With the highest module significance value and correlation coefficient, the blue module was selected as the key module, 19 genes were identified as the hub gene candidates. The above genes were significantly downregulated in KRAS mutant CRCs compared with the wild type. Four genes (AAR2, PSMA7, NELFCD, and PIGU) were further screened as the potential hub genes by the PPI network. Low expression of PIGU for KRAS mutant patients had a poor prognosis. Therefore, PIGU was identified as the hub gene. PIGU expression was also downregulated in other two CRC datasets. "MAPK SIGNALING PATHWAY" was enriched in PIGU lowly expressed samples. PIGU was identified and validated to be closely related to KRAS mutation. It could be a potential prognosis biomarker and a novel treatment target for KRAS mutant CRC patients.

Weighted Gene Coexpression Network Analysis Reveals the Dynamic Transcriptome Regulation and Prognostic Biomarkers of Hepatocellular Carcinoma

This study was aimed at revealing the dynamic regulation of mRNAs, long noncoding RNAs (lncRNAs), and microRNAs (miRNAs) in hepatocellular carcinoma (HCC) and to identify HCC biomarkers capable of predicting prognosis. Differentially expressed mRNAs (DEmRNAs), lncRNAs, and miRNAs were acquired by comparing expression profiles of HCC with normal samples, using an expression data set from The Cancer Genome Atlas. Altered biological functions and pathways in HCC were analyzed by subjecting DEmRNAs to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Gene modules significantly associated with disease status were identified by weighted gene coexpression network analysis. An lncRNA-mRNA and an miRNA-mRNA coexpression network were constructed for genes in disease-related modules, followed by the identification of prognostic biomarkers using Kaplan-Meier survival analysis. Differential expression and association with the prognosis of 4 miRNAs were verified in independent data sets. A total of 1220 differentially expressed genes were identified between HCC and normal samples. Differentially expressed mRNAs were significantly enriched in functions and pathways related to “plasma membrane structure,” “sensory perception,” “metabolism,” and “cell proliferation.” Two disease-associated gene modules were identified. Among genes in lncRNA-mRNA and miRNA-mRNA coexpression networks, 9 DEmRNAs and 7 DEmiRNAs were identified to be potential prognostic biomarkers. MIMAT0000102, MIMAT0003882, and MIMAT0004677 were successfully validated in independent data sets. Our results may advance our understanding of molecular mechanisms underlying HCC. The biomarkers may contribute to diagnosis in future clinical practice.

Prognostic value and oncogene function of heterogeneous nuclear ribonucleoprotein A1 overexpression in HBV-related hepatocellular carcinoma

Previous study has shown heterogeneous nuclear ribonucleoprotein A1(HNRNPA1) is highly expressed in various human cancers. In order to study the clinical value and potential function of HNRNPA1 in HBV-related hepatocellular carcinoma (HCC), three datasets from the GEPIA, GEO and TCGA were analyzed. HNRNPA1 expression was found to be significantly higher in HBV-positive HCC samples, which was supported with IHC validation. Both GO and KEGG analyses demonstrated that HNRNPA1 co-expressed genes were involved in translation, ribonucleoprotein complex biogenesis and assembly, ribosome biogenesis, RNA processing, RNA splicing, etc. Survival analysis showed a significant reduction in overall survival of patients with high HNRNPA1 expression from both the GSE14520 cohort and 151 patients with HBV-related HCC cohort. Furthermore, Gene set enrichment analysis (GSEA) revealed that HNRNPA1 may regulate HCC progression by influencing the cell cycle and WNT signaling pathway, etc. HNRNPA1 overexpression has diagnostic value in distinguishing between HCC and non-HCC liver tissue (AUC = 0.730). Finally, HNRNPA1 was a directly target gene of miR-22 manifested by the reduced luciferase activity and decreased HNRNPA1 expression in the cells with overexpression of miR-22. HNRNPA1 might function as an oncogene through the EGFR signaling pathway in HBV-related HCC, which has not been reported in previous studies.