Explore the vast range of titles available.

Background An in-depth understanding of immune evasion mechanisms in tumors is crucial to overcome resistance and enable innovative advances in immunotherapy. Circular RNAs (circRNAs) have been implicated in cancer progression. However, much remains unknown regarding whether circRNAs impact immune escape in non-small-cell lung carcinoma (NSCLC). Methods We performed bioinformatics analysis to profile and identify the circRNAs mediating immune evasion in NSCLC. A luciferase reporter assay, RNA immunoprecipitation (RIP), RNA pulldown assays and fluorescence in situ hybridization were performed to identify the interactions among circIGF2BP3, miR-328-3p, miR-3173-5p and plakophilin 3 (PKP3). In vitro T cell-mediated killing assays and in vivo syngeneic mouse models were used to investigate the functional roles of circIGF2BP3 and its downstream target PKP3 in antitumor immunity in NSCLC. The molecular mechanism of PKP3-induced PD-L1 upregulation was explored by immunoprecipitation, RIP, and ubiquitination assays. Results We demonstrated that circIGF2BP3 (hsa_circ_0079587) expression was increased in NSCLC and negatively correlated with CD8 + T cell infiltration. Functionally, elevated circIGF2BP3 inactivated cocultured T cells in vitro and compromised antitumor immunity in an immunocompetent mouse model, and this effect was dependent on CD8 + T cells. Mechanistically, METTL3 mediates the N 6 -methyladenosine (m 6 A) modification of circIGF2BP3 and promotes its circularization in a manner dependent on the m 6 A reader protein YTHDC1. circIGF2BP3 competitively upregulates PKP3 expression by sponging miR-328-3p and miR-3173-5p to compromise the cancer immune response. Furthermore, PKP3 engages with the RNA-binding protein FXR1 to stabilize OTUB1 mRNA, and OTUB1 elevates PD-L1 abundance by facilitating its deubiquitination. Tumor PD-L1 deletion completely blocked the impact of the circIGF2BP3/PKP3 axis on the CD8 + T cell response. The inhibition of circIGF2BP3/PKP3 enhanced the treatment efficacy of anti-PD-1 therapy in a Lewis lung carcinoma mouse model. Collectively, the PKP3/PD-L1 signature and the infiltrating CD8 + T cell status stratified NSCLC patients into different risk groups. Conclusion Our results reveal the function of circIGF2BP3 in causing immune escape from CD8 + T cell-mediated killing through a decrease in PD-L1 ubiquitination and subsequent proteasomal degradation by stabilizing OTUB1 mRNA in a PKP3-dependent manner. This work sheds light on a novel mechanism of PD-L1 regulation in NSCLC and provides a rationale to enhance the efficacy of anti-PD-1 treatment in NSCLC.

Background Esophageal squamous cell carcinoma (ESCC) is one of the most lethal forms of adult cancer with poor prognosis. Substantial evidence indicates that reactive oxygen species (ROS) are important modulators of aggressive cancer behavior. However, the mechanism by which ESCC cells integrate redox signals to modulate carcinoma progression remains elusive. Methods The expression of interferon alpha inducible protein 6 (IFI6) in clinical ESCC tissues and cell lines was detected by RT-PCR and Western blotting. The correlation between IFI6 expression levels and aggressive ESCC disease stage was examined by immunohistochemistry. Bioinformatic analysis was conducted to explore the potential function of IFI6 in ESCC. ESCC cell lines stably depleted of IFI6 and ectopically expressing IFI6 were established using lentiviruses expressing shRNAs and an IFI6 expression plasmid, respectively. The effects of IFI6 on ESCC cells were determined by cell-based analyses, including EdU assay, apoptotic assay, cellular and mitochondria-specific ROS detection, seahorse extracellular flux, and mitochondrial calcium flux assays. Blue native-polyacrylamide gel electrophoresis was used to determine mitochondrial supercomplex assembly. Transcriptional activation of NADPH oxidase 4 (NOX4) via ATF3 was confirmed by dual luciferase assay. In vivo tumor growth was determined in mouse xenograft models. Results We find that the expression of IFI6, an IFN-stimulated gene localized in the inner mitochondrial membrane, is markedly elevated in ESCC patients and a panel of ESCC cell lines. High IFI6 expression correlates with aggressive disease phenotype and poor prognosis in ESCC patients. IFI6 depletion suppresses proliferation and induces apoptosis by increasing ROS accumulation. Mechanistically, IFI6 ablation induces mitochondrial calcium overload by activating mitochondrial Ca 2+ uniporter and subsequently ROS production. Following IFI6 ablation, mitochondrial ROS accumulation is also induced by mitochondrial supercomplex assembly suppression and oxidative phosphorylation dysfunction, while IFI6 overexpression produces the opposite effects. Furthermore, energy starvation induced by IFI6 inhibition drives endoplasmic reticulum stress through disrupting endoplasmic reticulum calcium uptake, which upregulates NOX4-derived ROS production in an ATF3-dependent manner. Finally, the results in xenograft models of ESCC further corroborate the in vitro findings. Conclusion Our study unveils a novel redox homeostasis signaling pathway that regulates ESCC pathobiology and identifies IFI6 as a potential druggable target in ESCC.

Background Cisplatin-based chemotherapy is a mainstay systematic therapy for advanced esophageal squamous cell carcinoma (ESCC), and cisplatin resistance, which is not uncommon, is the major barrier to improving patient outcomes. Circular RNAs (circRNAs) are novel noncoding RNAs that are implicated in cancer progression, but their involvement in modulating cisplatin responsiveness in ESCC remains unknown. Methods Bioinformatics analysis was used to profile and identify the circRNAs involved in cisplatin responsiveness in ESCC. The chemosensitive role of cDOPEY2 was confirmed both in vitro and in vivo. The molecular mechanism of cDOPEY2 was investigated by mass spectrometry, immunoprecipitation, and ubiquitination analyses. Results We report that a novel circRNA (cDOPYE2, hsa_circ_0008078) was markedly downregulated in cisplatin-resistant ESCC cells (ESCC-CR) compared with parental chemosensitive cells. Re-expression of cDOPEY2 substantially enhanced the cell-killing ability of cisplatin by augmenting the apoptotic process in ESCC-CR cells, which was achieved by decreasing the abundance of the antiapoptotic protein Mcl-1. Mechanistically, we showed that cDOPEY2 acted as a protein scaffold to enhance the interaction between the cytoplasmic polyadenylation element binding protein (CPEB4) and the E3 ligase TRIM25, which in turn facilitated the ubiquitination and degradation of CPEB4. The increased Mcl-1 expression in ESCC-CR cells was dependent on the binding of CPEB4 to its untranslated mRNA, and depletion of CPEB4 mediated by cDOPEY2 reversed this effect. Rescue experiments confirmed that the critical role of cDOPEY2 in maintaining cisplatin sensitivity was dependent on the depletion of CEPB4 and its downstream target Mcl-1. Clinical and in vivo data further corroborated the significant relevance of cDOPEY2 to cisplatin responsiveness in ESCC. Conclusions We provide evidence that cDOPEY2 inhibits CPEB4-mediated Mcl-1 translation by promoting the ubiquitination and degradation of CPEB4 to alleviate cisplatin resistance, indicating that cDOPEY2 may serve as a valuable biomarker and potential therapeutic target in ESCC.

Background . Gliomas are primary malignant tumors of the central nervous system. The TEA domain transcription factor (TEAD) family proteins are the ultimate effector molecules of the Hippo pathway. However, their expression and function in gliomas have not been further studied. Methods . This study employed R software as the primary analysis tool. Public databases were used to analyze the expression and prognostic significance of TEADs. Functional enrichment analyses were conducted to determine the functions of the TEADs. We then explored their interaction with tumor‐infiltrating immune cells and immune checkpoint proteins (ICPs). A Cox regression model was used to estimate the prognostic value of the TEADs. Finally, we conducted experiments to confirm TEAD3’s function in vitro. Results . TEAD expression was frequently increased in glioma and other malignant tumors. High TEAD expression was found to be substantially linked with isocitrate dehydrogenase (IDH) wild type, noncodeletion of 1p/19q, high WHO grade, and poor prognosis in glioma patients. Functional analyses revealed TEAD involvement in cancer cell transcription. The high expression of TEADs was greatly related to the myeloid‐derived suppressor cells (MDSCs) and regulatory T‐cells (Tregs) infiltration. TEADs also showed significant correlations with ICP expression in glioma tissues. The Cox regression model demonstrated significant diagnostic and prognostic efficacy in glioma patients. The reduction in TEAD3 affects tumor cell proliferation, migration, invasion, and immune regulation. RNA sequencing disclosed that TEAD3 regulates immune‐related pathways, including negative regulation of the CTLA4 inhibitory pathway. Higher TEAD3 expression portended shorter overall survival (OS) and disease‐free survival (DFS) in patients with gliomas based on clinical samples. Conclusions . TEADs are overexpressed in gliomas and are associated with a poor prognosis. Importantly, this study discovered that TEADs influence the immunological milieu of glioma by modulating genes associated with immune infiltration.

Immunogenic cell death (ICD) regulators exert a crucial part in quite a few in numerous biological processes. This study aimed to determine the function and diagnostic value of ICD regulators in acute ischemic stroke (AIS). 31 significant ICD regulators were identified from the gene expression omnibus (GEO) database in this work (the combination of the GSE16561 dataset and the GSE37587 dataset in the comparison of non-AIS and AIS patients). The random forest model was applied and 15 potential ICD regulators were screened to forecast the probability of AIS. A nomogram, on the basis of 11 latent ICD regulators, was performed. The resolution curve analysis indicated that patients can gain benefits from the nomogram. The consensus clustering approach was applied, and AIS patients were divided into 2 ICD clusters (cluster A and cluster B) based on the identified key ICD regulatory factors. To quantify the ICD pattern, 181 ICD-related dissimilarly expressed genes (DEGs) were selected for further investigation. The expression levels of NFKB1, NFKB2, and PARP1 were greater in gene cluster A than in gene cluster B. In conclusion, ICD regulators exerted a crucial part in the progress of AIS. The investigation made by us on ICD patterns perhaps informs prospective immunotherapeutic methods for AIS.

Background. Gefitinib resistance remains a major problem in the treatment of lung cancer. However, the underlying mechanisms involved in gefitinib resistance are largely unclear. Methods. Open-accessed data of lung cancer patients were downloaded from The Cancer Genome Atlas Program and Gene Expression Omnibus databases. CCK8, colony formation, and 5-ethynyl-2′-deoxyuridine assays were utilized to evaluate the cell proliferation ability. Transwell and wound-healing assays were utilized to evaluate the cell invasion and migration ability. Quantitative real-time PCR was utilized to detect the RNA level of specific genes. Results. Here, we obtained the expression profile data of wild and gefitinib-resistant cells. Combined with the data from the TCGA and GDSC databases, we identified six genes, RNF150, FAT3, ANKRD33, AFF3, CDH2, and BEX1, that were involved in gefitinib resistance in both cell and tissue levels. We found that most of these genes were expressed in the fibroblast of the NSCLC microenvironment. Hence, we also comprehensively investigated the role of fibroblast in the NSCLC microenvironment, including its biological effect and cell interaction. Ultimately, CDH2 was selected for further analysis for its prognosis correlation. In vitro experiments presented the cancer-promoting role of CDH2 in NSCLC. Moreover, cell viability detection showed that the inhibition of CDH2 could significantly decrease the IC50 of gefitinib in NSCLC cells. GSEA showed that CDH2 could significantly affect the pathway activity of PI3K/AKT/mTOR signaling. Conclusions. This study is aimed at investigating the underlying mechanism involved in gefitinib resistance to lung cancer. Our research has improved researchers’ understanding of gefitinib resistance. Meanwhile, we found that CDH2 could lead to gefitinib resistance through PI3K/AKT/mTOR signaling.

Correction: J Exp Clin Cancer Res 39, 144 (2020) https://doi.org/10.1186/s13046-020-01646-3 Following the publication of the original article [1], the authors identified errors in the images of Fig. 3, Fig. 5, Fig. 8, Fig. 10 and Supplementary Material Table S4, specifically: * Fig.3D - incorrect image for Eca109 with IFI6-KD * Fig.5G - incorrect fluorescence data for TE-1 cells * Fig.8A - incorrect fluorescence image for Eca109 * Fig.8G - incorrect band of GAPDH for TE-1 cells * Fig.10C - incorrect representative image for IFI6 staining in the OEControl and IFI6-OE groups were included * Table S4 - Incorrect primer sequences for MCU, ATF3 and NCLX were uploaded The corrected figures are provided below: Fig.3D - incorrect image for Eca109 with IFI6-KD Fig.5G - incorrect fluorescence data for TE-1 cells Fig.8A - incorrect fluorescence image for Eca109 Fig.8G - incorrect band of GAPDH for TE-1 cells Fig.10C - incorrect representative image for IFI6 staining in the OEControl and IFI6-OE groups were included Table S4 - Incorrect primer sequences for MCU, ATF3 and NCLX were uploaded The corrected figures are provided below: Statistical significance was determined by one-way ANOVA. **P < 0.01 Full size image Correct Figure 3 Fig. 3 figure 2 IFI6 promotes cell proliferation, inhibits apoptosis and ameliorates oxidative stress in ESCC. a-b. Statistical significance was determined by one-way ANOVA. **P < 0.01. i. The indicated ESCC cells were incubated in the presence or absence of the MCU inhibitor DS16570511 (10 μM), and mitochondrial ROS levels were then measured by MitoSOX staining, followed by flow cytometry Full size image Correct Figure 5 Fig. 5 figure 4 IFI6 modulates mitochondrial ROS production by regulating mitochondrial Ca2+ overload. a-b.

Background Esophageal squamous cell carcinoma (ESCC) is a highly aggressive and treatment‐resistant tumor. The biological implications and molecular mechanism of cancer stem‐like cells (CSCs) in ESCC, which contribute to therapeutic resistance such as radioresistance, remain elusive. Methods Quantitative real‐time polymerase chain reaction, western blotting, immunohistochemistry, and in situ hybridization assays were used to detect methyltransferase‐like 14 miR‐99a‐5p tribble 2 (METTL14/miR‐99a‐5p/TRIB2) expression in ESCC. The biological functions of METTL14/miR‐99a‐5p/TRIB2 were demonstrated in vitro and in vivo. Mass spectrum analysis was used to identify the downstream proteins regulated by TRIB2. Chromatin immunoprecipitation (IP), IP, N6‐methyladenosine (m6A)‐RNA IP, luciferase reporter, and ubiquitination assays were employed to explore the molecular mechanisms underlying this feedback circuit and its downstream pathways. Results We found that miR‐99a‐5p was significantly decreased in ESCC. miR‐99a‐5p inhibited CSCs persistence and the radioresistance of ESCC cells, and miR‐99a‐5p downregulation predicted an unfavorable prognosis of ESCC patients. Mechanically, we unveiled a METTL14‐miR‐99a‐5p‐TRIB2 positive feedback loop that enhances CSC properties and radioresistance of ESCC cells. METTL14, an m6A RNA methyltransferase downregulated in ESCC, suppresses TRIB2 expression via miR‐99a‐5p‐mediated degradation of TRIB2 mRNA by targeting its 3′ untranslated region, whereas TRIB2 induces ubiquitin‐mediated proteasomal degradation of METTL14 in a COP1‐dependent manner. METTL14 upregulates miR‐99a‐5p by modulating m6A‐mediated, DiGeorge critical region 8‐dependent pri‐mir‐99a processing. Hyperactivation of TRIB2 resulting from this positive circuit was closely correlated with radioresistance and CSC characteristics. Furthermore, TRIB2 activates HDAC2 and subsequently induces p21 epigenetic repression through Akt/mTOR/S6K1 signaling pathway activation. Pharmacologic inhibition of HDAC2 effectively attenuates the TRIB2‐mediated effect both in vitro and in patient‐derived xenograft models. Conclusion Our data highlight the presence of the METTL14/miR‐99a‐5p/TRIB2 axis and show that it is positively associated with CSC characteristics and radioresistance of ESCC, suggesting potential therapeutic targets for ESCC treatment. 1. METTL14 upregulates miR‐99a‐5p by promoting m6A‐mediated, DGCR8‐dependent pri‐mir‐99a processing. 2. miR‐99a‐5p induces degradation of TRIB2 mRNA by targeting its 3′ UTR. 3. TRIB2 induces ubiquitin‐mediated proteasomal degradation of METTL14 in a COP1‐dependent manner. 4. METTL14/miR‐99a‐5p/TRIB2 constitutes a positive feedback loop that enhances CSC properties and radioresistance of ESCC cells through inducing HDAC2‐mediated p21 epigenetic repression dependent on Akt/mTOR/S6K1 pathway.

Background Neointimal hyperplasia induced by interventional surgery can lead to progressive obliteration of the vascular lumen, which has become a major factor affecting prognosis. The rate of re-endothelialization is known to be inversely related to neointima formation. Growth differentiation factor 11 (GDF11) is a secreted protein with anti-inflammatory, antioxidant, and antiaging properties. Recent reports have indicated that GDF11 can improve vascular remodeling by maintaining the differentiated phenotypes of vascular smooth muscle cells. However, it is not known whether and how GDF11 promotes re-endothelialization in vascular injury. The present study was performed to clarify the influence of GDF11 on re-endothelialization after vascular injury. Methods An adult Sprague–Dawley rat model of common carotid artery balloon dilatation injury was surgically established. A recombinant adenovirus carrying GDF11 was delivered into the common carotid artery to overexpress GDF11. Vascular re-endothelialization and neointima formation were assessed in harvested carotid arteries through histomolecular analysis. CCK-8 analysis, LDH release and Western blotting were performed to investigate the effects of GDF11 on endothelial NLRP3 inflammasome activation and relevant signaling pathways in vitro. Results GDF11 significantly enhanced re-endothelialization and reduced neointima formation in rats with balloon-dilatation injury by suppressing the activation of the NLRP3 inflammasome. Administration of an endoplasmic reticulum stress (ER stress) inhibitor, 4PBA, attenuated endothelial NLRP3 inflammasome activation induced by lysophosphatidylcholine. In addition, upregulation of LOX-1 expression involved elevated ER stress and could result in endothelial NLRP3 inflammasome activation. Moreover, GDF11 significantly inhibited NLRP3 inflammasome-mediated endothelial cell pyroptosis by negatively regulating LOX-1-dependent ER stress. Conclusions We conclude that GDF11 improves re-endothelialization and can attenuate vascular remodeling by reducing endothelial NLRP3 inflammasome activation. These findings shed light on new treatment strategies to promote re-endothelialization based on GDF11 as a future target.