Interleukin Enhancer Binding Factor 3 Research Articles

Deficiency of smooth muscle cell ILF3 alleviates intimal hyperplasia via HMGB1 mRNA degradation-mediated regulation of the STAT3/DUSP16 axis

Intimal hyperplasia is a complicated pathophysiological phenomenon attributable to in-stent restenosis, and the underlying mechanism remains unclear. Interleukin enhancer-binding factor 3 (ILF3), a double-stranded RNA-binding protein involved in regulating mRNA stability, has been recently demonstrated to assume a crucial role in cardiovascular disease; nevertheless, its impact on intimal hyperplasia remains unknown. In current study, we used samples of human restenotic arteries and rodent models of intimal hyperplasia, we found that vascular smooth muscle cell (VSMC) ILF3 expression was markedly elevated in human restenotic arteries and murine ligated carotid arteries. SMC-specific ILF3 knockout mice significantly suppressed injury induced neointimal formation. In vitro, platelet-derived growth factor type BB (PDGF-BB) treatment elevated the level of VSMC ILF3 in a dose- and time-dependent manner. ILF3 silencing markedly inhibited PDGF-BB-induced phenotype switching, proliferation, and migration in VSMCs. Transcriptome sequencing and RNA immunoprecipitation sequencing depicted that ILF3 maintained its stability upon binding to the mRNA of the high-mobility group box 1 protein (HMGB1), thereby exerting an inhibitory effect on the transcription of dual specificity phosphatase 16 (DUSP16) through enhanced phosphorylation of signal transducer and activator of transcription 3 (STAT3). Therefore, the results both in vitro and in vivo indicated that the loss of ILF3 in VSMC ameliorated neointimal hyperplasia by regulating the STAT3/DUSP16 axis through the degradation of HMGB1 mRNA. Our findings revealed that vascular injury activates VSMC ILF3, which in turn promotes intima formation. Consequently, targeting specific VSMC ILF3 may present a potential therapeutic strategy for ameliorating cardiovascular restenosis.

DHRS4-AS1 regulate gastric cancer apoptosis and cell proliferation by destabilizing DHX9 and inhibited the association between DHX9 and ILF3

Gastric cancer (GC) causes millions of cancer-related deaths due to anti-apoptosis and rapid proliferation. However, the molecular mechanisms underlying GC cell proliferation and anti-apoptosis remain unclear. The expression levels of DHRS4-AS1 in GC were analyzed based on GEO database and recruited GC patients in our institution. We found that DHRS4-AS1 was significantly downregulated in GC. The expression of DHRS4-AS1 in GC tissues showed a significant correlation with tumor size, advanced pathological stage, and vascular invasion. Moreover, DHRS4-AS1 levels in GC tissues were significantly associated with prognosis. DHRS4-AS1 markedly inhibited GC cell proliferation and promotes apoptosis in vitro and in vivo assays. Mechanically, We found that DHRS4-AS1 bound to pro-oncogenic DHX9 (DExH-box helicase 9) and recruit the E3 ligase MDM2 that contributed to DHX9 degradation. We also confirmed that DHRS4-AS1 inhibited DHX9-mediated cell proliferation and promotes apoptosis. Furthermore, we found DHX9 interact with ILF3 (Interleukin enhancer Binding Factor 3) and activate NF-kB Signaling in a ILF3-dependent Manner. Moreover, DHRS4-AS1 can also inhibit the association between DHX9 and ILF3 thereby interfered the activation of the signaling pathway. Our results reveal new insights into mechanisms underlying GC progression and indicate that LncRNA DHRS4-AS1 could be a future therapeutic target and a biomarker for GC diagnosis.

Genome-wide CRISPR screens identify ILF3 as a mediator of mTORC1-dependent amino acid sensing.

The mechanistic target of rapamycin complex 1 (mTORC1) is an essential hub that integrates nutrient signals and coordinates metabolism to control cell growth. Amino acid signals are detected by sensor proteins and relayed to the GATOR2 and GATOR1 complexes to control mTORC1 activity. Here we perform genome-wide CRISPR/Cas9 screens, coupled with an assay for mTORC1 activity based on fluorescence-activated cell sorting analysis of pS6, to identify potential regulators of mTORC1-dependent amino acid sensing. We then focus on interleukin enhancer binding factor 3 (ILF3), one of the candidate genes from the screen. ILF3 tethers the GATOR complexes to lysosomes to control mTORC1. Adding a lysosome-targeting sequence to the GATOR2 component WDR24 bypasses the requirement for ILF3 to modulate amino-acid-dependent mTORC1 signalling. ILF3 plays an evolutionarily conserved role in human and mouse cells, and in worms to regulate the mTORC1 pathway, control autophagy activity and modulate the ageing process.

E2F1-mediated KDM4A-AS1 up-regulation promotes EMT of hepatocellular carcinoma cells by recruiting ILF3 to stabilize AURKA mRNA

Hepatocellular carcinoma (HCC) is a gastrointestinal tumor with high clinical incidence. Long non-coding RNAs (lncRNAs) play vital roles in modulating the growth and epithelial-mesenchymal transition (EMT) of HCC. However, the underlying mechanism of lncRNA KDM4A antisense RNA 1 (KDM4A-AS1) in HCC remains elusive. In our study, the role of KDM4A-AS1 in HCC was systematically investigated. The levels of KDM4A-AS1, interleukin enhancer-binding factor 3 (ILF3), Aurora kinase A (AURKA), and E2F transcription factor 1 (E2F1) were determined by RT-qPCR or western blot. ChIP and dual luciferase reporter experiments were performed to detect the binding relationship between E2F1 and KDM4A-AS1 promoter sequence. RIP and RNA-pull down confirmed the interaction of ILF3 with KDM4A-AS1/AURKA. Cellular functions were analyzed by MTT, flow cytometry, wound healing and transwell assays. IHC was performed to detect Ki67 in vivo. We found that KDM4A-AS1 was increased in HCC tissues and cells. Elevated KDM4A-AS1 level was correlated to poor prognosis of HCC. Knockdown of KDM4A-AS1 inhibited the proliferation, migration, invasion and EMT of HCC cells. ILF3 bound to KDM4A-AS1 and AURKA. KDM4A-AS1 maintained the stability of AURKA mRNA by recruiting ILF3. E2F1 transcriptionally activated KDM4A-AS1. Overexpressed KDM4A-AS1 reversed the contribution of E2F1 depletion to AURKA expression and EMT in HCC cells. KDM4A-AS1 promoted tumor formation in vivo through the PI3K/AKT pathway. These results revealed that E2F1 transcriptionally activated KDM4A-AS1 to regulate HCC progression via the PI3K/AKT pathway. E2F1 and KDM4A-AS1 may serve as good prognostic targets for HCC treatment.

Characterization of circSCL38A1 as a novel oncogene in bladder cancer via targeting ILF3/TGF-β2 signaling axis

The regulatory role of circRNAs in cancer metastasis has become a focused issue in recent years. To date, however, the discovery of novel functional circRNAs and their regulatory mechanisms via binding with RBPs in bladder cancer (BC) are still lacking. Here, we screened out circSLC38A1 based on our sequencing data and followed validation with clinical tissue samples and cell lines. Functional assays showed that circSLC38A1 promoted BC cell invasion in vitro and lung metastasis of mice in vivo. By conducting RNA pull-down, mass spectrum, and RIP assays, circSLC38A1 was found to interact with Interleukin enhancer-binding factor 3 (ILF3), and stabilize ILF3 protein via modulating the ubiquitination process. By integrating our CUT&Tag-seq and RNA-seq data, TGF-β2 was identified as the functional target of the circSLC38A1-ILF3 complex. In addition, m6A methylation was enriched in circSLC38A1 and contributed to its upregulation. Clinically, circSLC38A1 was identified in serum exosomes of BC patients and could distinguish BC patients from healthy individuals with a diagnostic accuracy of 0.878. Thus, our study revealed an essential role and clinical significance of circSLC38A1 in BC via activating the transcription of TGF-β2 in an ILF3-dependent manner, extending the understanding of the importance of circRNA-mediated transcriptional regulation in BC metastasis.

Prognostic and immunotherapeutic predictive value of interleukin enhancer-binding factor 3 in hepatocellular carcinoma: Integrated bioinformatics and experimental analysis

Interleukin enhancer-binding factor 3 (ILF3) as an RNA-binding protein that plays a critical role in the process of cancer and antiviral responses. However, no researcher has focused on the pan-cancer analysis of ILF3, and the effect of ILF3 on tumor immunity is still largely unclear. This study synthetically analyzed the relationship between the expression of ILF3 across various cancers and prognosis, microsatellite instability (MSI), tumor mutational burden (TMB), tumor immune cell infiltration, and common immune checkpoint molecules by multiple bioinformatics databases. Experimentally, we detected the mRNA abundance of ILF3 and immune checkpoint molecules in liver hepatocellular carcinoma (LIHC) tissues. The functions of ILF3 on hepatocellular carcinoma (HCC) cells were verified by western blot assay and cytotoxicity assay. We found that ILF3 was aberrantly expressed and associated with the prognosis in several types of tumors. The ILF3 expression was significantly correlated with infiltrating levels of immune cells and immune molecules in certain cancers, particularly in LIHC. Detection of clinical liver cancer tissues confirmed the positive correlation between ILF3 and immune checkpoint molecules, including programmed cell death 1 (PD-1), programmed cell death ligand 1 (PD-L1), cytotoxic T lymphocyte-associated antigen 4 (CTLA4), lymphocyte-activation gene 3 (LAG3), and T cell immunoglobulin domain and mucin domain-3 (TIM3). Furthermore, reduced PD-L1 and increased sensitivity of HCC cells to T cells cytotoxicity were found in ILF3-knockdown cells. This work suggested ILF3 may be used as a prognostic marker for various tumors to predict the response to immunotherapy.

The Macrophage-Associated LncRNA MALR Facilitates ILF3 Liquid-Liquid Phase Separation to Promote HIF1α Signaling in Esophageal Cancer.

Secretion of TNFα by tumor-associated macrophages stimulates cancer cells to upregulate lncRNA MALR, which induces ILF3 liquid-liquid phase separation and activation of HIF1α signaling to promote cancer progression.

RNA binding protein POP7 regulates ILF3 mRNA stability and expression to promote breast cancer progression.

RNA binding proteins (RBPs) play pivotal roles in breast cancer (BC) development. As an RBP, Processing of precursor 7 (POP7) is one of the subunits of RNase P and RNase MRP, however, its exact function and mechanism in BC remain unknown. Here, we showed that expression of POP7 was frequently increased in BC cells and in primary breast tumors. Upregulated POP7 significantly promoted BC cell proliferation in vitro and primary tumor growth in vivo. POP7 also increased cell migration, invasion in vitro, and lung metastasis in vivo. Through RNA immunoprecipitation coupled with sequencing (RIP-seq), we found that POP7 bound preferentially to intron regions and POP7-binding peak associated genes were mainly enriched in cancer-related pathways. Furthermore, POP7 regulated Interleukin Enhancer Binding Factor 3 (ILF3) expression through influencing its mRNA stability. Knockdown of ILF3 significantly impaired the increased malignant potential of POP7-overexpressing cells, suggesting that POP7 enhances BC progression through regulating ILF3 expression. Collectively, our findings provide the first evidence for the important role of POP7 and its regulation of ILF3 in promoting BC progression.

Ox-LDL-mediated ILF3 overexpression in gastric cancer progression by activating the PI3K/AKT/mTOR signaling pathway.

Background: This study aimed to investigate the relationship of dyslipidemia and interleukin-enhancer binding factor 3 (ILF3) in gastric cancer, and provide insights into the potential application of statins as an agent to prevent and treat gastric cancer.Methods: The expression levels of ILF3 in gastric cancer were examined with publicly available datasets such as TCGA, and western blotting and immunohistochemistry were performed to determine the expression of ILF3 in clinical specimens. The effects of ox-LDL on expression of ILF3 were further verified with western blot analyses. RNA sequencing, Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA) pathway analyses were performed to reveal the potential downstream signaling pathway targets of ILF3. The effects of statins and ILF3 on PI3K/AKT/mTOR signaling pathway, cell proliferation, cell cycle, migration and invasion of gastric cancer cells were investigated with Edu assay, flow cytometry and transwell assay.Results: Immunohistochemistry and western blot demonstrated that the positive expression rates of ILF3 in gastric cancer tissues were higher than adjacent mucosa tissues. The ox-LDL promoted the expression of ILF3 in a time-concentration-dependent manner. ILF3 promoted the proliferation, cell cycle, migration and invasion by activating the PI3K/AKT/mTOR signaling pathway. Statins inhibited the proliferation, cell cycle, migration and invasion of gastric cancer by inhibiting the expression of ILF3.Conclusions: These findings demonstrate that ox-LDL promotes ILF3 overexpression to regulate gastric cancer progression by activating the PI3K/AKT/mTOR signaling pathway. Statins inhibits the expression of ILF3, which might be a new targeted therapy for gastric cancer.

ILF3 represses repeat-derived microRNAs targeting RIG-I mediated type I interferon response

MicroRNAs (miRNAs) play important roles in regulated gene expression and miRNA biogenesis is also subject to regulation, together constituting critical regulatory circuitries in numerous physiological and pathological processes. As a dsRNA binding protein, interleukin enhancer binding factor 3 (ILF3) has been implicated as a negative regulator in miRNA biogenesis, but the mechanism and specificity have remained undefined. Here, combining small-RNA-seq and CLIP-seq, we showed that ILF3 directly represses many miRNAs or perhaps other types of small RNAs annotated in both miRBase and MirGeneDB. We demonstrated that ILF3 preferentially binds to A/U-enriched motifs, which tend to lengthen and/or stabilize the stem-loop in pri-miRNAs, thereby effectively competing with the Microprocessor to block miRNA biogenesis. Focusing on the biological function of ILF3-suppressed miR-582-3p, we discovered that this LINE-derived miRNA targets a critical interferon-inducible gene RIG-I for repression, thus establishing a novel ILF3/miR-582/RIG-I axis in the antiviral response.

Systematic identification of NF90 target RNAs by iCLIP analysis

RNA-binding proteins (RBPs) interact with and determine the fate of many cellular RNAs directing numerous essential roles in cellular physiology. Nuclear Factor 90 (NF90) is an RBP encoded by the interleukin enhancer-binding factor 3 (ILF3) gene that has been found to influence RNA metabolism at several levels, including pre-RNA splicing, mRNA turnover, and translation. To systematically identify the RNAs that interact with NF90, we carried out iCLIP (individual-nucleotide resolution UV crosslinking and immunoprecipitation) analysis in the human embryonic fibroblast cell line HEK-293. Interestingly, many of the identified RNAs encoded proteins involved in the response to viral infection and RNA metabolism. We validated a subset of targets and investigated the impact of NF90 on their expression levels. Two of the top targets, IRF3 and IRF9 mRNAs, encode the proteins IRF3 and IRF9, crucial regulators of the interferon pathway involved in the SARS-CoV-2 immune response. Our results support a role for NF90 in modulating key genes implicated in the immune response and offer insight into the immunological response to the SARS-CoV-2 infection.

ILF3 is responsible for hyperlipidemia-induced arteriosclerotic calcification by mediating BMP2 and STAT1 transcription

Calcification is common in atherosclerotic plaque and can induce vulnerability, which further leads to myocardial infarction, plaque rupture and stroke. The mechanisms of atherosclerotic calcification are poorly characterized. Interleukin enhancer binding factor 3 (ILF3) has been identified as a novel factor affecting dyslipidemia and stroke subtypes. However, the precise role of ILF3 in atherosclerotic calcification remains unclear. In this study, we used smooth muscle-conditional ILF3 knockout (ILF3SM-KO) and transgenic mice (ILF3SM-Tg) and macrophage-conditional ILF3 knockout (ILF3M-KO) and transgenic (ILF3M-Tg) mice respectively. Here we showed that ILF3 expression is increased in calcified human aortic vascular smooth muscle cells (HAVSMCs) and calcified atherosclerotic plaque in humans and mice. We then found that hyperlipidemia increases ILF3 expression and exacerbates calcification of VSMCs and macrophages by regulating bone morphogenetic protein 2 (BMP2) and signal transducer and activator of transcription 1 (STAT1) transcription. We further explored the molecular mechanisms of ILF3 in atherosclerotic calcification and revealed that ILF3 acts on the promoter regions of BMP2 and STAT1 and mediates BMP2 upregulation and STAT1 downregulation, which promotes atherosclerotic calcification. Our results demonstrate the effect of ILF3 in atherosclerotic calcification. Inhibition of ILF3 may be a useful therapy for preventing and even reversing atherosclerotic calcification.

Protein regulation strategies of the mouse spleen in response to Babesia microti infection

BackgroundBabesia is a protozoan parasite that infects red blood cells in some vertebrates. Some species of Babesia can induce zoonoses and cause considerable harm. As the largest immune organ in mammals, the spleen plays an important role in defending against Babesia infection. When infected with Babesia, the spleen is seriously injured but still actively initiates immunomodulatory responses.MethodsTo explore the molecular mechanisms underlying the immune regulation and self-repair of the spleen in response to infection, this study used data-independent acquisition (DIA) quantitative proteomics to analyse changes in expression levels of global proteins and in phosphorylation modification in spleen tissue after Babesia microti infection in mice.ResultsAfter mice were infected with B. microti, their spleens were seriously damaged. Using bioinformatics methods to analyse dynamic changes in a large number of proteins, we found that the spleen still initiated immune responses to combat the infection, with immune-related proteins playing an important role, including cathepsin D (CTSD), interferon-induced protein 44 (IFI44), interleukin-2 enhancer-binding factor 2 (ILF2), interleukin enhancer-binding factor 3 (ILF3) and signal transducer and activator of transcription 5A (STAT5A). In addition, some proteins related to iron metabolism were also involved in the repair of the spleen after B. microti infection, including serotransferrin, lactoferrin, transferrin receptor protein 1 (TfR1) and glutamate-cysteine ligase (GCL). At the same time, the expression and phosphorylation of proteins related to the growth and development of the spleen also changed, including protein kinase C-δ (PKC-δ), mitogen-activated protein kinase (MAPK) 3/1, growth factor receptor-bound protein 2 (Grb2) and P21-activated kinase 2 (PAK2).ConclusionsImmune-related proteins, iron metabolism-related proteins and growth and development-related proteins play an important role in the regulation of spleen injury and maintenance of homeostasis. This study provides an important basis for the diagnosis and treatment of babesiosis.Graphical

Cereblon Promotes the Ubiquitination and Proteasomal Degradation of Interleukin Enhancer-Binding Factor 2.

Interleukin enhancer-binding factor 2 (ILF2) forms a heterodimer with interleukin enhancer-binding factor 3 (ILF3) via double-stranded RNA-binding motif and zinc finger associated domain and thus regulates gene expression and cancer cell growth. However, how ILF2 is degraded in cells remains elusive. In this work, using stable isotope labeling by amino acids in cell culture (SILAC) quantitative proteomics, we find that ILF2 is downregulated in cells expressing cereblon (CRBN). Using affinity purification and immunoblotting analysis, we demonstrate that CRBN interacts with ILF2 and functions as a substrate receptor of the cullin-4 RING E3 ligase complex. Biochemical experiments disclose that CRBN expression reduces ILF2 protein level and this reduction is diminished when the proteasome is inhibited. Upon protein synthesis inhibition, the degradation of ILF2 is enhanced by CRBN. Moreover, CRBN promotes the ubiquitination of ILF2 and thus results in the ubiquitin-mediated proteasomal degradation. Analyses of previously identified post-translational modification sites and the crystal structure of ILF2 discover the potential ubiquitination sites on ILF2. Through mutagenesis and biochemical experiments, we further reveal that the K45R mutation completely abolishes the effect of CRBN on ILF2, suggesting that this is the key residue responsible for its ubiquitination. Taken together, we identify an E3 ligase that regulates ILF2 and uncover a molecular pathway for its degradation. This work might be helpful to elucidate the molecular mechanism by which CRBN regulates diverse cellular functions.

HOXB‐AS1 accelerates the tumorigenesis of glioblastoma via modulation of HOBX2 and HOBX3 at transcriptional and posttranscriptional levels

Glioblastoma (GBM) is the most universal and invasive brain tumor among adults. Increasing studies have reported that long noncoding RNAs play vital roles in regulating downstream molecules at the transcriptional or posttranscriptional level in tumor progression. The purpose of the current research was to inquire the modulation mechanism by which homeobox B cluster antisense RNA 1 (HOXB-AS1) functioned in GBM. Our study first discovered the lifted expression of HOXB-AS1 and its nearby genes HOXB2 and HOXB3 in GBM and the positive relationship between HOXB-AS1 and HOXB2 or HOXB3. Loss-of-function assays and in vivo study detected that silencing of HOXB-AS1, HOXB2, or HOXB3 restrained the proliferation and induced the apoptosis in GBM. In addition, mechanism experiments demonstrated that HOXB-AS1 recruited interleukin enhancer-binding factor 3 (ILF3) to regulate HOXB2 and HOXB3 expression at the transcriptional level, and HOXB-AS1 sponged miR-186-5p to modulate HOXB2 and HOXB3 expression at posttranscriptional level. Finally, the regulatory mechanism of HOXB-AS1 in GBM was certified through rescue experiments. Our results indicated that HOXB-AS1 boost the HOXB2 or HOXB3 expression at the transcriptional and posttranscriptional levels. We detected the HOXB-AS1-ILF3-HOXB2/HOXB3 axis and HOXB-AS1-miR-186-5p-HOXB2/HOXB3 axis driving the GBM progression, which might generate more effective diagnostic biomarkers and therapeutic targets for patients with GBM.

Long Noncoding RNA Rps4l Mediates the Proliferation of Hypoxic Pulmonary Artery Smooth Muscle Cells

Pulmonary hypertension (PH) is a rare and fatal disorder involving the vascular remodeling of pulmonary arteries mediated by the enhanced proliferation of pulmonary artery smooth muscle cells (PASMCs). Long noncoding RNAs are a subclass of regulatory molecules with diverse cellular functions, but their role in PH remains largely unexplored. We aimed to identify and determine the functions of long noncoding RNAs involved in hypoxia-induced PH and PASMC proliferation. RNA sequencing in a hypoxic mouse model identified hypoxia-regulated long noncoding RNAs, including Rps4l. Rps4l expression was significantly reduced in PH-model mice and hypoxic PASMCs. The subcellular localization of Rps4l was detected by RNA fluorescence in situ hybridization and quantification of nuclear/cytoplasmic RNA. Rps4l overexpression rescued pulmonary arterial hypertension features, as demonstrated by right ventricle hypertrophy, right ventricular systolic pressure, hemodynamics, cardiac function, and vascular remodeling. At the cellular level, Rps4l overexpression weakened cell viability and proliferation and suppressed cell cycle progression. Potential Rps4l-binding proteins were identified via RNA pull-down followed by mass spectrometry, RNA immunoprecipitation, and microscale thermophoresis. These results indicated that Rps4l is associated with and affects the stabilization of ILF3 (interleukin enhancer-binding factor 3). Rps41 further regulates the levels of HIF-1α and consequently leads to hypoxia-induced PASMC proliferation and migration. Our results showed that in hypoxic PASMCs, Rps4l expression decreases due to regulation by hypoxia. This decrease affects the proliferation, migration, and cell cycle progression of PASMCs through ILF3/HIF-1α. These results provide a theoretical basis for further investigations into the pathological mechanism of hypoxic PH and may provide insight for the development of novel treatments.

LncRNA IGF2 AS Regulates Bovine Myogenesis through Different Pathways

The role of long non-coding RNA (lncRNA) in the regulation of bovine skeletal muscle development remains poorly understood. The present study investigated the function and regulatory mechanism of a novel lncRNA, insulin-like growth factor 2 antisense transcript (IGF2 AS), in bovine myoblast proliferation and differentiation. Gain or loss of IGF2 AS was performed using an expression plasmid or small interfering RNA (siRNA), respectively. Bovine myoblasts were used to investigate the biological function and mechanisms of IGF2 AS in vitro. Results were conjointly analyzed by celluar and molecular biology experiments as well as bioinformatics. Functionally, IGF2 AS could promote proliferation and differentiation of bovine myoblasts. The preliminary mechanism suggests, on the one hand, that IGF2 AS could complement the IGF2 gene intron region and affect the stability and expression of IGF2 mRNA. On the other hand, RNA pull-down and immunoprecipitation assays demonstrated that IGF2 AS could directly bind to the interleukin enhancer binding factor 3 (ILF3) protein and maybe partly though it to regulate myogenesis. In conclusion, the novel identified lncRNA IGF2 AS promoted proliferation and differentiation of bovine myoblasts through various pathways.

P53 and H3K4me2 activate N6-methylated LncPGCAT-1 to regulate primordial germ cell formation via MAPK signaling.

Long noncoding RNAs (lncRNAs) participate in the formation of primordial germ cells (PGCs); however, the identity of the key lncRNAs and the molecular mechanisms responsible for the formation of PGCs remain unknown. Here, we identify a key candidate lncRNA (lncRNA PGC transcript-1, LncPGCAT-1) via RNA sequencing of embryonic stem cells, PGCs, and Spermatogonial stem cells (SSCs). Functional experiments confirmed that LncPGCAT-1 positively regulated the formation of PGCs by elevating the expression of Cvh and C-kit while downregulating the pluripotency(Nanog) in vitro and in vivo; PAS staining of genital ridges in vivo also showed that interference with LncPGCAT-1 can significantly reduce the number of PGCs in genital ridges, while overexpression of LncPGCAT-1 had the opposite result. The result of luciferase reporter assay combined with CHIP-qPCR showed that the expression of LncPGCAT-1 was promoted by the transcription factor P53 and high levels of H3K4me2. Mechanistically, the luciferase reporter assay confirmed that mitogen-activated protein kinase 1 (MAPK1) was the target gene of LncPGCAT-1 and gga-mir-1591. In the ceRNA system, high levels of N6 methylation of LncPGCAT-1 enhanced the adsorption capacity of LncPGCAT-1 for gga-mir-1591. Adsorption of gga-mir-1591 activated the MAPK1/ERK signaling cascade by relieving the gga-mir-1591-dependent inhibition of MAPK1 expression. Moreover, LncPGCAT-1 interacted with interleukin enhancer binding factor 3 (ILF3) to regulate the ubiquitination of P53 and phosphorylation of JNK. Interaction with ILF3 resulted in positive self-feedback regulation of LncPGCAT-1 and activation of JNK signaling, ultimately promoting PGC formation. Altogether, the study expands our knowledge of the function and molecular mechanisms of lncRNAs in PGC development.

High expression of interleukin-enhancer binding factor 3 predicts poor prognosis in patients with lung adenocarcinoma.

Interleukin-enhancer binding factor 3 (ILF3) is a double-stranded RNA-binding protein that has been reported to contribute to the occurrence and progression of various malignant tumors. The aim of the present study was to evaluate the prognostic value of ILF3 and to apply this knowledge to avoid excessive medical treatment in patients with lung adenocarcinoma (LUAD). ILF3 expression in a discovery set consisting of tumor and peri-tumor tissue microarrays was analyzed using immunohistochemical methods. The mRNA level of ILF3 was subsequently analyzed in a validation set downloaded from The Cancer Genome Atlas. The Kaplan-Meier method, univariate and multivariate Cox analyses, decision curve analysis and nomogram models were used to evaluate the prognostic value of ILF3. ILF3 expression was upregulated in tumor tissues compared with peri-tumor tissues and was negatively associated with the overall survival time of patients with LUAD in the discovery and validation sets. Moreover, ILF3 expression was used for risk stratification in patients with tumor-node-metastasis stages II–IV and poor-to-moderate tumor differentiation. ILF3 expression was identified as an independent predictor of adverse prognosis for patients with LUAD in the discovery and validation sets. Finally, nomogram models for the 3- and 5 year survival time of patients with LUAD revealed that ILF3 expression may be used to improve the predictive accuracy of the prognosis and to avoid excessive medical treatment for certain patients with the disease. Overall, the data obtained in the current study revealed that high ILF3 expression was associated with poor prognosis, and demonstrated that ILF3, as a potential independent risk factor, may improve the hierarchical postoperative management of patients with LUAD.

ILF3 is a substrate of SPOP for regulating serine biosynthesis in colorectal cancer

The Serine–Glycine–One-Carbon (SGOC) pathway is pivotal in multiple anabolic processes. Expression levels of SGOC genes are deregulated under tumorigenic conditions, suggesting participation of oncogenes in deregulating the SGOC biosynthetic pathway. However, the underlying mechanism remains elusive. Here, we identified that Interleukin enhancer-binding factor 3 (ILF3) is overexpressed in primary CRC patient specimens and correlates with poor prognosis. ILF3 is critical in regulating the SGOC pathway by directly regulating the mRNA stability of SGOC genes, thereby increasing SGOC genes expression and facilitating tumor growth. Mechanistic studies showed that the EGF–MEK–ERK pathway mediates ILF3 phosphorylation, which hinders E3 ligase speckle-type POZ protein (SPOP)-mediated poly-ubiquitination and degradation of ILF3. Significantly, combination of SGOC inhibitor and the anti-EGFR monoclonal antibody cetuximab can hinder the growth of patient-derived xenografts that sustain high ERK-ILF3 levels. Taken together, deregulation of ILF3 via the EGF–ERK signaling plays an important role in systemic serine metabolic reprogramming and confers a predilection toward CRC development. Our findings indicate that clinical evaluation of SGOC inhibitor is warranted for CRC patients with ILF3 overexpression.