CstF64-Induced Shortening of the BID 3'UTR Promotes Esophageal Squamous Cell Carcinoma Progression by Disrupting ceRNA Cross-talk with ZFP36L2

Fateful Decisions of Where to Cut the Line: Pathology Associated with Aberrant 3' End Processing and Transcription Termination

Aberrant gene expression lies at the heart of many pathologies. This review will point out how 3' end processing, the final mRNA-maturation step in the transcription cycle, is surprisingly prone to regulated as well as stochastic variations with a wide range of consequences. Whereas smaller variations contribute to the plasticity of gene expression, larger alternations to 3' end processing and coupled transcription termination can lead to pathological consequences. These can be caused by the local mutation of one gene or affect larger numbers of genes systematically, if aspects of the mechanisms of 3' end processing and transcription termination are altered.

Highly expressed of BID indicates poor prognosis and mediates different tumor microenvironment characteristics in clear cell renal cell carcinoma

BACKGROUND

Studies have found that BH3 interacting domain death agonist (BID) is closely related to the occurrence and development of many kinds of tumors. However, little attention has been paid to the situation of BID in clear cell renal cell carcinoma (ccRCC). So, our aim was to explore the effect of BID in ccRCC.

METHODS

Survival analysis, ROC curve, correlation analysis and Cox regression analysis were executed to analyze the prognostic value and clinical correlation of BID in ccRCC. The risk prognosis model was constructed in the training cohort and further validated in the internal testing cohort, ICGC cohort, and GEO cohort. Transcriptome sequencing and immunohistochemical staining of clinical specimens were used to validate the results of bioinformatics analysis. The GSEA, ESTIMATE algorithm, CIBERSORT algorithm, ssGSEA, TIDE score, correlation and difference analysis were used to analyze the effects of BID on immune infiltration in tumor microenvironment (TME).

RESULTS

BID was highly expressed in ccRCC tissues, which was verified by transcriptome sequencing and immunohistochemical staining of clinical specimens. Patients with high expression of BID had a worse prognosis. BID is an independent prognostic factor for ccRCC. The prognostic model based on BID can accurately predict the prognosis of patients in different cohorts. In addition, the expression levels of BID was closely related to immunomodulatory molecules such as PD-1, LAG3, and CTLA4. Enrichment analysis indicated that BID was significantly enriched in immune-related responses and cancer-related pathways. The change of BID expression mediates different characteristics of immune infiltration in TME.

CONCLUSIONS

BID is highly expressed in ccRCC, which is a reliable biomarker of ccRCC prognosis. It is closely related to TME, and may be a potential target for immunotherapy in patients with ccRCC.

The Transcriptional Landscape of Immune-Response 3'-UTR Alternative Polyadenylation in Melanoma

The prognosis of patients with malignant melanoma has been improved in recent decades due to advancements in immunotherapy. However, a considerable proportion of patients are refractory to treatment, particularly at advanced stages. This underscores the necessity of developing a new strategy to improve it. Alternative polyadenylation (APA), as a marker of crucial posttranscriptional regulation, has emerged as a major new type of epigenetic marker involved in tumorigenesis. However, the potential roles of APA in shaping the tumor microenvironment (TME) are largely unexplored. Herein, we collected two cohorts comprising melanoma patients who received immune checkpoint inhibitor (ICI) immunotherapy to quantify transcriptome-wide discrepancies in APA. We observed a global change in 3'-UTRs between responders and non-responders, which might involve DNA damage response, angiogenesis, PI3K-AKT signaling pathways, etc. Ten putative master APA regulatory factors for those APA events were detected via a network analysis. Notably, we established an immune response-related APA scoring system (IRAPAss), which exhibited a great performance of predicting immunotherapy response in multiple cohorts. Furthermore, we examined the correlation of APA with TME at the single-cell level using four single-cell immune profiles of tumor-infiltrating lymphocytes (TILs), which revealed an overall discrepancy in 3'-UTR length across diverse T cell populations, probably contributing to immunoregulation in melanoma. In conclusion, our study provides a transcriptional landscape of APA implicated in immunoregulation, which might lay the foundation for developing a new strategy for improving immunotherapy response for melanoma patients by targeting APA.

Transcriptome Responses to Different Salinity Conditions in Litoditis marina, Revealed by Long-Read Sequencing

The marine nematode Litoditis marina is widely distributed in intertidal zones around the globe, yet the mechanisms underlying its broad adaptation to salinity remain elusive. In this study, we applied ONT long-read sequencing technology to unravel the transcriptome responses to different salinity conditions in L. marina. Through ONT sequencing under 3‱, 30‱ and 60‱ salinity environments, we obtained 131.78 G clean data and 26,647 non-redundant long-read transcripts, including 6464 novel transcripts. The DEGs obtained from the current ONT lrRNA-seq were highly correlated with those identified in our previously reported Illumina short-read RNA sequencing data. When we compared the 30‱ to the 3‱ salinity condition, we found that GO terms such as oxidoreductase activity, cation transmembrane transport and ion transmembrane transport were shared between the ONT lrRNA-seq and Illumina data. Similarly, GO terms including extracellular space, structural constituents of cuticle, substrate-specific channel activity, ion transport and substrate-specific transmembrane transporter activity were shared between the ONT and Illumina data under 60‱ compared to 30‱ salinity. In addition, we found that 79 genes significantly increased, while 119 genes significantly decreased, as the salinity increased. Furthermore, through the GO enrichment analysis of 214 genes containing DAS, in 30‱ compared to 3‱ salinity, we found that GO terms such as cellular component assembly and coenzyme biosynthetic process were enriched. Additionally, we observed that GO terms such as cellular component assembly and coenzyme biosynthetic process were also enriched in 60‱ compared to 30‱ salinity. Moreover, we found that 86, 125, and 81 genes that contained DAS were also DEGs, in comparisons between 30‱ and 3‱, 60‱ and 30‱, and 60‱ and 3‱ salinity, respectively. In addition, we demonstrated the landscape of alternative polyadenylation in marine nematode under different salinity conditions This report provides several novel insights for the further study of the mechanisms by which euryhalinity formed and evolved, and it might also contribute to the investigation of salinity dynamics induced by global climate change.

Super-enhancers: Implications in gastric cancer

Gastric cancer (GC) is the fifth most prevalent malignancy and the third leading cause of cancer-related mortality globally. Despite intensive efforts to enhance the efficiencies of various therapeutics (chemotherapy, surgical interventions, molecular-targeted therapies, immunotherapies), the prognosis for patients with GC remains poor. This might be predominantly due to the limited understanding of the complicated etiology of GC. Importantly, epigenetic modifications and alterations are crucial during GC development. Super-enhancers (SEs) are a large cluster of adjacent enhancers that greatly activate transcription. SEs sustain cell-specific identity by enhancing the transcription of specific oncogenes. In this review, we systematically summarize how SEs are involved in GC development, including the SE landscape in GC, the SE target genes in GC, and the interventions related to SE functions for treating GC.

The role of CSTF2 in cancer: from technology to clinical application

A protein called cleavage-stimulating factor subunit 2 (CSTF2, additionally called CSTF-64) binds RNA and is needed for the cleavage and polyadenylation of mRNA. CSTF2 is an important component subunit of the cleavage stimulating factor (CSTF), which is located on the X chromosome and encodes 557 amino acids. There is compelling evidence linking elevated CSTF2 expression to the pathological advancement of cancer and on its impact on the clinical aspects of the disease. The progression of cancers, including hepatocellular carcinoma, melanoma, prostate cancer, breast cancer, and pancreatic cancer, is correlated with the upregulation of CSTF2 expression. This review provides a fresh perspective on the investigation of the associations between CSTF2 and various malignancies and highlights current studies on the regulation of CSTF2. In particular, the mechanism of action and potential clinical applications of CSTF2 in cancer suggest that CSTF2 can serve as a new biomarker and individualized treatment target for a variety of cancer types.

Genetic Variants That Impact Alternative Polyadenylation in Cancer Represent Candidate Causal Risk Loci

Alternative polyadenylation (APA) is emerging as a major mechanism of posttranscriptional regulation. APA can impact the development and progression of cancer, suggesting that the genetic determinants of APA might play an important role in regulating cancer risk. Here, we depicted a pan-cancer atlas of human APA quantitative trait loci (apaQTL), containing approximately 0.7 million apaQTLs across 32 cancer types. Systematic multiomics analyses indicated that cancer apaQTLs could contribute to APA regulation by altering poly(A) motifs, RNA-binding proteins (RBP), and chromatin regulatory elements and were preferentially enriched in genome-wide association studies (GWAS)-identified cancer susceptibility loci. Moreover, apaQTL-related genes (aGene) were broadly related to cancer signaling pathways, high mutational burden, immune infiltration, and drug response, implicating their potential as therapeutic targets. Furthermore, apaQTLs were mapped in Chinese colorectal cancer tumor tissues and then screened for functional apaQTLs associated with colorectal cancer risk in 17,789 cases and 19,951 controls using GWAS-ChIP data, with independent validation in a large-scale population consisting of 6,024 cases and 10,022 controls. A multi-ancestry-associated apaQTL variant rs1020670 with a C>G change in DNM1L was identified, and the G allele contributed to an increased risk of colorectal cancer. Mechanistically, the risk variant promoted aberrant APA and facilitated higher usage of DNM1L proximal poly(A) sites mediated by the RBP CSTF2T, which led to higher expression of DNM1L with a short 3'UTR. This stabilized DNM1L to upregulate its expression, provoking colorectal cancer cell proliferation. Collectively, these findings generate a resource for understanding APA regulation and the genetic basis of human cancers, providing insights into cancer etiology.

SIGNIFICANCE

Cancer risk is mediated by alternative polyadenylation quantitative trait loci, including the rs1020670-G variant that promotes alternative polyadenylation of DNM1L and increases colorectal cancer risk.

Prognostic Value of Necroptosis-Related Genes Signature in Oral Squamous Cell Carcinoma

The dual role of necroptosis in inhibiting and promoting tumor development has gradually received much attention because of its essential significance for targeted treatment. Accordingly, this study aims to explore the relationship between necroptosis and oral squamous cell carcinoma (OSCC), and search for novel prognostic factors for OSCC. RNA-seq data and clinical information were downloaded from TCGA and GTEx databases. The prognostic signature of necroptosis-related genes (NRGs) was constructed by univariate Cox regression analysis and the LASSO Cox regression model. Moreover, survival analyses, ROC curves, and nomograms were adopted to further analyze. GO and KEGG analyses and immune infiltration analyses were used for function enrichment and immune feature research in turn. The NRG prognostic signature expression was higher in OSCC tissues than in normal tissues, and the overall survival (OS) rate of the high-expression group was much lower. HPRT1 was proved to be an independent prognostic factor in OSCC. Furthermore, the function enrichment analyses revealed that NRGs were involved in necroptosis, apoptosis, inflammation, and immune reaction. The expression of NRGs was related to immunosuppression in OSCC. Furthermore, the knockdown of HPRT1 could suppress the proliferation and migration of OSCC. In conclusion, the high expression of NRG prognostic signature is associated with poor prognosis in OSCC, and HPRT1 can serve as a novel independent prognostic factor for OSCC.

NUDT21 alters glioma migration through differential alternative polyadenylation of LAMC1

PURPOSE

Gliomas and their surrounding microenvironment constantly interact to promote tumorigenicity, yet the underlying posttranscriptional regulatory mechanisms that govern this interplay are poorly understood.

METHODS

Utilizing our established PAC-seq approach and PolyAMiner bioinformatic analysis pipeline, we deciphered the NUDT21-mediated differential APA dynamics in glioma cells.

RESULTS

We identified LAMC1 as a critical NUDT21 alternative polyadenylation (APA) target, common in several core glioma-driving signaling pathways. qRT-PCR analysis confirmed that NUDT21-knockdown in glioma cells results in the preferred usage of the proximal polyA signal (PAS) of LAMC1. Functional studies revealed that NUDT21-knockdown-induced 3'UTR shortening of LAMC1 is sufficient to cause translational gain, as LAMC1 protein is upregulated in these cells compared to their respective controls. We demonstrate that 3'UTR shortening of LAMC1 after NUDT21 knockdown removes binding sites for miR-124/506, thereby relieving potent miRNA-based repression of LAMC1 expression. Remarkably, we report that the knockdown of NUDT21 significantly promoted glioma cell migration and that co-depletion of LAMC1 with NUDT21 abolished this effect. Lastly, we observed that LAMC1 3'UTR shortening predicts poor prognosis of low-grade glioma patients from The Cancer Genome Atlas.

CONCLUSION

This study identifies NUDT21 as a core alternative polyadenylation factor that regulates the tumor microenvironment through differential APA and loss of miR-124/506 inhibition of LAMC1. Knockdown of NUDT21 in GBM cells mediates 3'UTR shortening of LAMC1, contributing to an increase in LAMC1, increased glioma cell migration/invasion, and a poor prognosis.

The RNA-binding protein CSTF2 regulates BAD to inhibit apoptosis in glioblastoma

RNA-binding proteins (RBP) regulate several aspects of co- and post-transcriptional gene expression in cancer cells. CSTF2 is involved in the expression of many cellular mRNAs and involved in the 3'-end cleavage and polyadenylation of pre-mRNAs to terminate transcription. However, the role of CSTF2 in human glioblastoma (GBM) and the underlying mechanisms remain unclear. In the present study, CSTF2 was found to be upregulated in GBM, and its high expression predicted poor prognosis. Knockdown CSTF2 induced GBM cell apoptosis both in vitro and in vivo. Specific mechanism studies showed that CSTF2 unstabilized the mRNA of the BAD protein by shortening its 3' UTR. Additionally, an increase in the expression level of CSTF2 decreased the expression level of BAD. In conclusion, CSTF2 binds to the mRNA of the BAD protein to shorten its 3'UTR, which negatively affects the BAD mediated apoptosis and promotes GBM cell survival.

CSTF2 Acts as a Prognostic Marker Correlated with Immune Infiltration in Hepatocellular Carcinoma

Background

Cleavage stimulation factor 2 (CSTF2) encodes a nuclear protein that is implicated in the development of various cancers. However, the role of CSTF2 in hepatocellular carcinoma (HCC) has not been understood. This study aims to explore the function of CSTF2 in HCC.

Methods

The expression, diagnostic capability, prognostic value, and immune cell effect of CSTF2 in HCC were explored using various databases. The expression level of CSTF2 were validated in our cell lines. The effect of CSTF2 on hepatocarcinogenesis was explored by CSTF2 silencing.

Results

CSTF2 expression was significantly elevated in HCC and correlated with multiple clinicopathological characteristics. CSTF2 exhibited good diagnostic capability in discriminating HCC samples from nontumorous samples. High CSTF2 expression was significantly related to poor overall survival. Univariate and multivariate Cox regression analyses suggested that CSTF2 expression was an independent risk factor for HCC. These results were validated in ICGC cohorts. In addition, the nomogram based on CSTF2 showed better predictive performance than the AJCC staging system in TCGA and ICGC cohorts. Functional enrichment analysis revealed that CSTF2-related genes were involved in DNA/RNA processing and the cell cycle. In addition, we found that CSTF2 expression was closely related to the levels of various infiltrating immune cells, especially neutrophils. Moreover, some immune checkpoints had positive relationships with CSTF2 expression. CSTF2 silencing inhibited proliferation, invasion and migration, and promoted apoptosis in HepG2 cells. Western blotting analysis revealed that CSTF2 silencing inactivated the Wnt/β-catenin signaling pathway.

Conclusion

High CSTF2 expression not only correlates with unfavorable outcomes but also affects immune cell infiltration and immune checkpoint expression in HCC. CSTF2 silencing can alleviate the malignant phenotypes of hepatic cancer cell by inactivating the Wnt/β-catenin signaling pathway. These results indicate that CSTF2 can serve as a promising prognostic marker and therapeutic target for HCC patients.

Targeting the mRNA endonuclease CPSF73 inhibits breast cancer cell migration, invasion, and self-renewal

Cleavage by the endonuclease CPSF73 and polyadenylation of nascent RNA is an essential step in co-transcriptional mRNA maturation. Recent work has surprisingly identified CPSF73 as a promising drug target for inhibiting the growth of specific cancers, triggering further studies on understanding CPSF73 regulation and functions in cells. Here, we report that a HECT-like E3 ligase, UBE3D, participates in stabilizing CPFS73 protein by preventing its ubiquitin-mediated degradation by the proteasome. Depletion of UBE3D leads to CPSF73 downregulation, a pre-mRNA cleavage defect, and dysregulated gene expression in cells. UBE3D dysfunction or chemical inactivation of CPSF73 inhibited migration and invasion as well as stem cell renewal phenotypes in vitro in triple-negative breast cancer cells. In addition, genetic overexpression of CPSF73 promoted breast cancer stemness and knocking down CPSF73 inhibited stem cell renewal properties. Together, our findings indicate that targeting the pre-mRNA processing nuclease CPSF73 has potential for breast cancer therapy.

Construction of a ceRNA Network and Comprehensive Analysis of lncRNA in Hepatocellular Carcinoma

To explore the RNA biomolecular marker associated with hepatocellular carcinoma (HCC) prognosis, we constructed a regulatory network of competitive endogenous RNAs (ceRNAs), which provides favorable conditions for the early diagnosis, prognostic monitoring, and personalized treatment of HCC. In this study, the differentially expressed genes (DEGs) of patients with HCC were obtained from the Gene Expression Omnibus. We identified 574 upregulated genes and 274 downregulated genes relevant to HCC occurrence (p < 0.05). Subsequently, we constructed the protein−protein interaction (PPI) network using these DEGs and identified the hub genes from the PPI. We then determined the expression and prognostic values of the hub genes from the GEPIA and Kaplan−Meier plotter databases. After the upstream microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) were respectively identified by miRTarBase and miRNet, we validated the expression of the key miRNAs in the serum using qPCR experiments. Moreover, we identified a two-lncRNA (LINC01184 and ADORA2A-AS1) signature from the upstream lncRNA that effectively predicted overall survival and had promotive effects for HCC. To verify the clinical significance of the signature, we validated the expression of the lncRNA in HCC tissues. Finally, we discovered and identified four mRNAs, four miRNAs, and five lncRNAs associated with the prognosis of HCC and constructed a new ceRNA regulatory network, which will be beneficial for the accurate diagnosis and treatment of HCC.