microRNA-9a-5p disrupts the ELAVL1/VEGF axis to alleviate traumatic brain injury

Plasma microRNA (miR)-9 has been identified as a promising diagnostic biomarker for traumatic brain injury (TBI). This study aims to investigate the possible role and mechanisms of miR-9a-5p affecting TBI. Microarray-based gene expression profiling of TBI was used for screening differentially expressed miRNAs and genes. TBI rat models were established. miR-9a-5p, ELAVL1 and VEGF expression in the brain tissue of TBI rats was detected. The relationship among miR-9a-5p, ELAVL1 and VEGF was tested. TBI modeled rats were injected with miR-9a-5p-, ELAVL1 or VEGF-related sequences to identify their effects on TBI. miR-9a-5p was poorly expressed in the brain tissue of rats with TBI. ELAVL1 was a downstream target gene of miR-9a-5p, which could negatively regulate its expression. Enforced miR-9a-5p expression prevented brain tissue damage in TBI rats by targeting ELAVL1. Meanwhile, ELAVL1 could increase the expression of VEGF, which was highly expressed in the brain tissue of rats with TBI. In addition, ectopically expressed miR-9a-5p alleviated brain tissue damage in TBI rats by downregulating the ELAVL1/VEGF axis. Overall, miR-9a-5p can potentially reduce brain tissue damage in TBI rats by targeting ELAVL1 and down-regulating VEGF expression.

LncRNA HOST2 promotes NSUN2-mediated breast cancer progression via interaction with ELAVL1

Breast cancer (BC) is the most prevalent malignant tumor in women worldwide with high morbidity and mortality. NSUN2, a crucial RNA methyltransferase, plays a pivotal role in regulating the proliferation and metastasis of tumor cells. Our study demonstrated that NSUN2 is upregulated in BC tissues and cell lines, and its high expression is associated with a poor prognosis in BC patients. Knockout of NSUN2 exerted inhibitory effects on the proliferation and migration of BC cells in vitro and in vivo. Mechanistic investigations revealed that the RNA-binding protein ELAVL1 can bind to NSUN2 mRNA and increase its stability. Additionally, we identified HOST2, a long non-coding RNA, as a key player in blocking the ubiquitin-dependent proteasomal degradation of ELAVL1, thereby influencing the stability of NSUN2 mRNA. In conclusion, this study revealed for the first time that HOST2 maintains NSUN2 mRNA stability by blocking ubiquitin-dependent degradation of ELAVL1, which in turn affects BC progression. HOST2/ELAVL1/NSUN2 oncogenic cascade has the potential to be a novel therapeutic target for BC.

SUMOylation controls Hu antigen R posttranscriptional activity in liver cancer

The posttranslational modification of proteins critically influences many biological processes and is a key mechanism that regulates the function of the RNA-binding protein Hu antigen R (HuR), a hub in liver cancer. Here, we show that HuR is SUMOylated in the tumor sections of patients with hepatocellular carcinoma in contrast to the surrounding tissue, as well as in human cell line and mouse models of the disease. SUMOylation of HuR promotes major cancer hallmarks, namely proliferation and invasion, whereas the absence of HuR SUMOylation results in a senescent phenotype with dysfunctional mitochondria and endoplasmic reticulum. Mechanistically, SUMOylation induces a structural rearrangement of the RNA recognition motifs that modulates HuR binding affinity to its target RNAs, further modifying the transcriptomic profile toward hepatic tumor progression. Overall, SUMOylation constitutes a mechanism of HuR regulation that could be potentially exploited as a therapeutic strategy for liver cancer.

Lopinavir enhances anoikis by remodeling autophagy in a circRNA-dependent manner

Macroautophagy/autophagy-mediated anoikis resistance is crucial for tumor metastasis. As a key autophagy-related protein, ATG4B has been demonstrated to be a prospective anti-tumor target. However, the existing ATG4B inhibitors are still far from clinical application, especially for tumor metastasis. In this study, we identified a novel circRNA, circSPECC1, that interacted with ATG4B. CircSPECC1 facilitated liquid-liquid phase separation of ATG4B, which boosted the ubiquitination and degradation of ATG4B in gastric cancer (GC) cells. Thus, pharmacological addition of circSPECC1 may serve as an innovative approach to suppress autophagy by targeting ATG4B. Specifically, the circSPECC1 underwent significant m6A modification in GC cells and was subsequently recognized and suppressed by the m6A reader protein ELAVL1/HuR. The activation of the ELAVL1-circSPECC1-ATG4B pathway was demonstrated to mediate anoikis resistance in GC cells. Moreover, we also verified that the above pathway was closely related to metastasis in tissues from GC patients. Furthermore, we determined that the FDA-approved compound lopinavir efficiently enhanced anoikis and prevented metastasis by eliminating repression of ELAVL1 on circSPECC1. In summary, this study provides novel insights into ATG4B-mediated autophagy and introduces a viable clinical inhibitor of autophagy, which may be beneficial for the treatment of GC with metastasis.

CircSEMA6A upregulates PRRG4 by targeting MiR-520h and recruiting ELAVL1 to affect cell invasion and migration in papillary thyroid carcinoma

Objective

As the most prevalent type of thyroid malignancy, papillary thyroid carcinoma (PTC) accounts for over 80% of all thyroid cancers. Circular RNAs (circRNAs) have been found to regulate multiple cancers, including PTC.

Materials and methods

Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to analyse RNA and protein levels. Fluorescence in situ hybridization (FISH) was used to detect the distribution of the target genes. Functional experiments and animal experiments were implemented to analyse the biological functions of target genes in vitro and in vivo. Luciferase reporter, RNA pulldown, RNA binding protein immunoprecipitation (RIP) and mRNA stability assays were used to probe the underlying mechanisms.

Results

CircSEMA6Awas found to be upregulated in PTC tissues and cells, and its circular structure was verified. CircSEMA6A promotes PTC cell migration and invasion. Moreover, circSEMA6A functions as a competing endogenous RNA (ceRNA) to upregulate proline rich and Gla domain 4 (PRRG4) expression by sponging microRNA-520h (miR-520h). CircSEMA6A recruits ELAV1 to stabilize PRRG4 mRNA and drives PTC progression via PRRG4.

Conclusion

CircSEMA6A upregulates PRRG4 by targeting miR-520h and recruiting ELAVL1 to affect the invasion and migration of PTC cells, offering insight into the molecular mechanisms of PTC.

Dynamic proximity interaction profiling suggests that YPEL2 is involved in cellular stress surveillance

YPEL2 is a member of the evolutionarily conserved YPEL family involved in cellular proliferation, mobility, differentiation, senescence, and death. However, the mechanism by which YPEL2, or YPEL proteins, mediates its effects is largely unknown. Proteins perform their functions in a network of proteins whose identities, amounts, and compositions change spatiotemporally in a lineage-specific manner in response to internal and external stimuli. Here, we explored interaction partners of YPEL2 by using dynamic TurboID-coupled mass spectrometry analyses to infer a function for the protein. Our results using inducible transgene expressions in COS7 cells indicate that proximity interaction partners of YPEL2 are mainly involved in RNA and mRNA metabolic processes, ribonucleoprotein complex biogenesis, regulation of gene silencing by miRNA, and cellular responses to stress. We showed that YPEL2 interacts with the RNA-binding protein ELAVL1 and the selective autophagy receptor SQSTM1. We also found that YPEL2 localizes stress granules in response to sodium arsenite, an oxidative stress inducer, which suggests that YPEL2 participates in stress granule-related processes. Establishing a point of departure in the delineation of structural/functional features of YPEL2, our results suggest that YPEL2 may be involved in stress surveillance mechanisms.

The critical roles of lnc-GLYATL2-2/PD-L1 axis in immune microenvironment and the clinical value of intracranial chordomas

Intracranial chordomas (ICs) are associated with a poor prognosis due to low total resection rates and high recurrence rates. However, the role of immunotherapy in ICs remains unknown. RNA sequencing and immunohistochemical staining were performed on IC tissues and normal tissues, and the long noncoding RNA (lncRNA) lnc-GLYATL2-2 was identified. The results indicated that high expression of lnc-GLYATL2-2 was positively correlated with the tumor-infiltrating lymphocyte (TIL) markers CD4 and Foxp3, negatively correlated with CD8, and positively correlated with the expression of the immune checkpoint molecules programmed death receptor-1 (PD-1) and programmed death ligand 1 (PD-L1). Additionally, Kaplan-Meier and univariate or multivariate Cox regression analyses revealed the predictive value of lnc-GLYATL2-2 for survival based on clinical data from patients with ICs. A high expression level of lnc-GLYATL2-2 is potentially correlated with a suppressive tumor immune microenvironment and adverse clinical outcomes in IC patients. Mechanistically, the upregulation of lnc-GLYATL2-2 can result in increased cytoplasmic levels of ELAVL1, leading to enhanced binding to the 3'-UTR of PD-L1 mRNA and maintenance of its stability. In contrast, lnc-GLYATL2-2 can directly interact with the PD-L1 protein to prevent degradation, thereby promoting high levels of PD-L1 expression simultaneously at the transcriptional and translational levels in chordoma cells. These results provide a new perspective on the diagnosis and prognosis of ICs and provide theoretical evidence for immunotherapy in patients with ICs.

IL-17 promotes melanoma through TRAF2 as a scaffold protein recruiting PIAS2 and ELAVL1 to induce EPHA5

An abnormal immune response induces melanoma development. IL-17 and the classical downstream signal STAT1 are associated with melanoma development. TRAF2 also mediates the downstream signaling of IL-17; however, its role in IL-17-stimulated melanoma remains unclear. Bioinformatic analysis revealed that TRAF2 can bind to PIAS2 (a SUMO E3 ligase), ELAVL1 (an RNA-binding protein), and EPHA5 (an ephrin receptor of the tyrosine kinase family). To elucidate the IL-17 downstream signal, the IL-17 receptor (R), STAT1, TRAF2, PIAS2, ELAVL1, and EPHA5 were knocked down before melanoma cells were treated with recombinant IL-17A protein. Co-immunoprecipitation and RNA immunoprecipitation were conducted to determine the interaction of TRAF2 with PIAS2, ELAVL1, and EPHA5 proteins, as well as the interaction of ELAVL1 protein with EPHA5 mRNA. STAT1 knockdown suppressed the proliferation and invasion triggered by IL-17A, but the suppressive effects were much weaker than those caused by IL-17R knockdown. This implies that another nonclassical signal mediates IL-17 effects. IL-17A induces TRAF2 recruitment of ELAVL1, PIAS2, and EPHA5 proteins. We speculated that ELAVL1 bound to the AU-rich elements in the 3' untranslated region of the EPHA5 mRNA, thereby enhancing mRNA stability. Furthermore, PIAS2 induced EPHA5 SUMOylation, which suppressed EPHA5 ubiquitination and degradation. Through pre- and post-translational regulation, IL-17A induced EPHA5 expression in melanoma, and EPHA5 knockdown markedly suppressed IL-17A-induced proliferation and invasion. This study revealed a non-classical signaling mechanism responsible for the effects of IL-17 in melanoma.

Up-regulation of miR-192-5p inhibits the ELAVL1/PI3Kδ axis and attenuates microvascular endothelial cell proliferation, migration and angiogenesis in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that poses a threat to adults. MicroRNAs (miRNAs) play a key role in DR progression. However, the role and mechanism of miR-192-5p in DR remain unclear. We aimed to investigate the effect of miR-192-5p on cell proliferation, migration and angiogenesis in DR.

METHODS

Expression of miR-192-5p, ELAV-like RNA binding protein 1 (ELAVL1) and phosphoinositide 3-kinase delta (PI3Kδ) in human retinal fibrovascular membrane (FVM) samples and human retinal microvascular endothelial cells (HRMECs) was assessed using RT-qPCR. ELAVL1 and PI3Kδ protein levels were evaluated by Western blot. RIP and dual luciferase reporter assays were performed to confirm the miR-192-5p/ELAVL1/PI3Kδ regulatory networks. Cell proliferation, migration and angiogenesis were assessed by CCK8, transwell and tube formation assays.

RESULTS

MiR-192-5p was decreased in FVM samples from DR patients and high glucose (HG)-treated HRMECs. Functionally, overexpressed miR-192-5p inhibited cell proliferation, migration and angiogenesis in HG-treated HRMECs. Mechanically, miR-192-5p directly targeted ELAVL1 and decreased its expression. We further verified that ELAVL1 bound to PI3Kδ and maintained PI3Kδ mRNA stability. Rescue analysis demonstrated that the suppressive effects of HG-treated HRMECs caused by miR-192-5p up-regulation were overturned by overexpressed ELAVL1 or PI3Kδ.

CONCLUSION

MiR-192-5p attenuates DR progression by targeting ELAVL1 and reducing PI3Kδ expression, suggesting a biomarker for the treatment of DR.

Targeting AHR Increases Pancreatic Cancer Cell Sensitivity to Gemcitabine through the ELAVL1-DCK Pathway

The aryl hydrocarbon receptor (AHR) is a transcription factor that is commonly upregulated in pancreatic ductal adenocarcinoma (PDAC). AHR hinders the shuttling of human antigen R (ELAVL1) from the nucleus to the cytoplasm, where it stabilises its target messenger RNAs (mRNAs) and enhances protein expression. Among these target mRNAs are those induced by gemcitabine. Increased AHR expression leads to the sequestration of ELAVL1 in the nucleus, resulting in chemoresistance. This study aimed to investigate the interaction between AHR and ELAVL1 in the pathogenesis of PDAC in vitro. AHR and ELAVL1 genes were silenced by siRNA transfection. The RNA and protein were extracted for quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analysis. Direct binding between the ELAVL1 protein and AHR mRNA was examined through immunoprecipitation (IP) assay. Cell viability, clonogenicity, and migration assays were performed. Our study revealed that both AHR and ELAVL1 inter-regulate each other, while also having a role in cell proliferation, migration, and chemoresistance in PDAC cell lines. Notably, both proteins function through distinct mechanisms. The silencing of ELAVL1 disrupts the stability of its target mRNAs, resulting in the decreased expression of numerous cytoprotective proteins. In contrast, the silencing of AHR diminishes cell migration and proliferation and enhances cell sensitivity to gemcitabine through the AHR-ELAVL1-deoxycytidine kinase (DCK) molecular pathway. In conclusion, AHR and ELAVL1 interaction can form a negative feedback loop. By inhibiting AHR expression, PDAC cells become more susceptible to gemcitabine through the ELAVL1-DCK pathway.

RNA Structural Dynamics Modulate EGFR-TKI Resistance Through Controlling YRDC Translation in NSCLC Cells

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) positively affect the initial control of non-small cell lung cancer (NSCLC). Rapidly acquired resistance to EGFR-TKIs is a major hurdle in successful treatment. However, the mechanisms that control the resistance of EGFR-TKIs remain largely unknown. RNA structures have widespread and crucial functions in many biological regulations; however, the functions of RNA structures in regulating cancer drug resistance remain unclear. Here, the psoralen analysis of RNA interactions and structures (PARIS) method is used to establish the higher-order RNA structure maps of EGFR-TKIs-resistant and -sensitive cells of NSCLC. Our results show that RNA structural regions are enriched in untranslated regions (UTRs) and correlate with translation efficiency (TE). Moreover, yrdC N6-threonylcarbamoyltransferase domain containing (YRDC) promotes resistance to EGFR-TKIs. RNA structure formation in YRDC 3' UTR suppresses embryonic lethal abnormal vision-like 1 (ELAVL1) binding, leading to EGFR-TKI sensitivity by impairing YRDC translation. A potential therapeutic strategy for cancer treatment is provided using antisense oligonucleotide (ASO) to perturb the interaction between RNA and protein. Our study reveals an unprecedented mechanism through which the RNA structure switch modulates EGFR-TKI resistance by controlling YRDC mRNA translation in an ELAVL1-dependent manner.

ELAVL1 promotes LPS-induced endothelial cells injury through modulation of cytokine storm

Sepsis is a life-threatening systemic organ dysfunction caused by the host's unregulated response to a widespread bacterial infection. Endothelial injury is a major pathophysiologic symptom of sepsis and is considered a critical factor in promoting the progression of disease severity. ELAV like RNA binding protein 1(ELAVL1) is a ubiquitously expressed RNA-binding protein that may play an important role during sepsis. Nonetheless, the molecular mechanisms of ELAVL1 on endothelial cell damage in sepsis have not been well defined. Here, we aimed to confirm the role of ELAVL1 in sepsis-induced endothelial cell damage using lipopolysaccharide (LPS)-induced zebrafish and endothelial cells (ECs) models. We found that zebrafish larvae treated with LPS exhibited systemic endothelial cell damage, mostly manifested as pericardial edema, curved tail, and impaired angiogenesis. LPS treatments also significantly induced the expression levels of inflammatory cytokines (interleukin-6 (IL-6), IL-8, and tumor necrosis factor (TNF)-α) in vivo. In vitro, we observed the increase of ELAVL1 cytoplasmic translocation with LPS treatment. Mechanistically, targeted disruption of the ELAVL1 gene decreased the expression of TNF-α, IL-6, and IL-8 during induction of sepsis and alleviated LPS-induced blood vessel injury in zebrafish. Taken together, our study indicates that ELAVL1 knockdown may alleviate sepsis-induced endothelial cells injury by suppressing cytokine storm. Our research suggests that inhibition of ELAVL1 could reduce the level of inflammatory cytokine production induced by LPS and protect against endothelial cell injury. ELAVL1 might be a potential therapeutic target to block endothelial cells injury associated with sepsis.

[LINC00926 promotes pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells by recruiting ELAVL1]

OBJECTIVE

To investigate the regulatory role of the long non-coding RNA LINC00926 in pyroptosis of hypoxia-induced human umbilical vein vascular endothelial cells (HUVECs) and explore the molecular mechanism.

METHODS

HUVECs were transfected with a LINC00926-overexpressing plasmid (OE-LINC00926), a siRNA targeting ELAVL1, or both, followed by exposure to hypoxia (5% O2) or normoxia. The expression of LINC00926 and ELAVL1 in hypoxia-treated HUVECs was detected using real-time quantitative PCR (RT-qPCR) and Western blotting. Cell proliferation was detected using Cell Counting Kit-8 (CCK-8), and the levels of IL-1β in the cell cultures was determined with ELISA. The protein expression levels of pyroptosis-related proteins (caspase-1, cleaved caspase-1 and NLRP3) in the treated cells were analyzed using Western blotting, and the binding between LINC00926 and ELAVL1 was verified with RNA immunoprecipitation (RIP) assay.

RESULTS

Exposure to hypoxia obviously up-regulated the mRNA expression of LINC00926 and the protein expression of ELAVL1 in HUVECs, but did not affect the mRNA expression of ELAVL1. LINC00926 overexpression in the cells significantly inhibited cell proliferation, increased IL-1β level and enhanced the expressions of pyroptosis-related proteins (all P < 0.05). LINC00926 overexpression further up-regulated the protein expression of ELAVL1 in hypoxia-exposed HUVECs. The results of RIP assay confirmed the binding between LINC00926 and ELAVL1. ELAVL1 knockdown significantly decreased IL-1β level and the expressions of pyroptosis-related proteins in hypoxia-exposed HUVECs (P < 0.05), while LINC00926 overexpression partially reversed the effects of ELAVL1 knockdown.

CONCLUSION

LINC00926 promotes pyroptosis of hypoxia-induced HUVECs by recruiting ELAVL1.

Genomic organization, evolution and functional characterization of embryonic lethal abnormal vision like protein 1 (ELAVL1) in miiuy croaker (Miichthys miiuy)

Embryonic lethal vision-like protein 1 (ELAVL1), an AU-rich elements (AREs) binding protein involved in the regulation of inflammatory transcript stability, which has not been reported in fish. In this study, we identified the ELAVL1 gene in Miichthys miiuy (mmiELAVL1), and then analyzed its structure and evolution, furthermore described its expression pattern in miiuy croaker. The results showed that mmiELAVL1 and other vertebrate ELAVL1 genes all have three highly conserved RNA recognition motif (RRM) protein domains, and the structure and protein structure are evolutionarily conserved, indicating that their functions may also conservative. In healthy miiuy croaker, mmiELAVL1 was commonly expressed in the tested tissues, and mmiELAVL1 is mainly localized in the nucleus of kidney cells. In addition, mmiELAVL1 responds to poly(I:C) and SCRV stimulation and promotes antiviral genes, indicating its active role in immune process. In summary, this study will facilitate future studies on the role and underlying mechanisms of ELAVL1 in fish immune responses.

Long non-coding RNA DNMBP-AS1 promotes prostate cancer development by regulating LCLAT1

Prostate cancer (PCa) is as a serious threat to male's health around the world. Recent studies have indicated that long non-coding RNAs (lncRNAs) occupy an important position in various human cancers. However, the function and mechanism of lncRNA DNMBP antisense RNA 1 (DNMBP-AS1) in PCa is rarely investigated. RT-qPCR analysis was used to test gene expression. CCK-8, colony formation, EdU staining and transwell assays were conducted to assess the function of DNMBP-AS1 on PCa cell behaviors. RNA pull down, RIP and luciferase reporter assays were implemented to verify the mechanism of DNMBP-AS1. DNMBP-AS1 was obviously up-regulated in PCa cell lines. Functionally, DNMBP-AS1 knockdown weakened cell proliferation, migration and invasion of PCa. Mechanistically, DNMBP-AS1 sponged microRNA-6766-3p (miR-6766-3p) to regulate lysocardiolipin acyltransferase 1 (LCLAT1) expression. Furthermore, DNMBP-AS1 could stabilize LCLAT1 expression by recruiting ELAV like RNA binding protein 1 (ELAVL1). Consequently, rescue assays demonstrated that DNMBP-AS1 regulated PCa cell proliferation, migration and invasion through enhancing LCLAT1 expression. Collectively, we elucidated the function and regulatory mechanism of DNMBP-AS1 and provided the first evidence of DNMBP-AS1 as a driver for PCa.

HuR modulation with tanshinone mimics impairs LPS response in murine macrophages

Lipopolysaccharide exposure to macrophages induces an inflammatory response that is heavily regulated at the transcriptional and post-transcriptional levels. HuR (ELAVL1) is an RNA binding protein that binds and regulates the maturation and half-life of AU/U rich elements (ARE) containing cytokines and chemokines transcripts, mediating the LPS-induced response. Here we investigated how and to what extent small molecule tanshinone mimics (TMs) inhibiting HuR-RNA interaction counteract LPS stimulus in macrophages. We show TMs exist in solution in keto-enolic tautomerism and that, by molecular dynamic calculations, the orto quinone form is the bioactive species interacting with HuR and inhibiting its binding mode vs mRNA targets. A chemical blockage of the diphenolic, reduced form as a diacetate caused the loss of activity of TMs in vitro but resulted to prodrug-like activity in vivo. The murine macrophage cell line RAW264.7 was treated with LPS and TMs, and the modulation of cellular LPS-induced response was monitored by RNA and Ribonucleoprotein immunoprecipitation sequencing. Correlation analyses indicated that LPS induced a strong coupling between differentially expressed genes and HuR-bound genes, and that TMs reduced such interactions. Functional annotation addressed a specific set of genes involved in chemotaxis and immune response, such as Cxcl10, Il1b, Cd40, and Fas, with a decreased association with HuR, a reduction of their expression and protein secretion. The same effect was observed in primary murine bone marrow-derived macrophages, and in vivo in an LPS induced peritonitis model, in which the serum level of Cxcl10 and Il1b was strongly reduced, endowing TMs such as TM7nox with remarkable anti-inflammatory properties in vivo.

Proteomic profiling and ROC analysis identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug in resistant TNBC

Triple-negative breast cancer is high heterogeneous, aggressive, and metastatic with poor prognosis. Despite of advances in targeted therapies, TNBC has been reported to cause high morbidity and mortality. A rare subpopulation within the tumor microenvironment organized into a hierarchy of cancer stem cells is responsible for therapy resistance and tumor recurrence. Repurposing of antiviral drugs for cancer treatment is gaining momentum due to reduced cost, labour, and research time, but limited due to lack of prognostic, and predictive markers. The present study investigates proteomic profiling and ROC analysis to identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug 2-thio-6-azauridine (TAU) in resistant TNBC. The stemness of MDA-MB 231 and MDA-MD 468 adherent cells was enriched by culturing them under non-adherent and non-differentiation conditions. Then, CD151⁺ subpopulation was isolated and characterized for the enrichment of stemness. This study found that CD151 has overexpressed in stemness enriched subpopulations, and also showed CD44 high and CD24 low expression along with stem cell-related transcription factors octamer-binding transcription factor 4 (OCT4) and Sex determining Y-box 2 (SOX2). This study also found that TAU induced significant cytotoxicity and genotoxicity in the CD151⁺TNBC subpopulation and inhibited their proliferation by inducing DNA damage, cell cycle arrest at the G₂M phase, and apoptosis. Further, a proteomic profiling study showed that the expression of CD151 along with ELAVL1, an RNA-binding protein, was significantly reduced with TAU treatment. KM plotter showed correlation of CD151 and ELAVL1 gene expression with a poor prognosis of TNBC. ROC analysis predicted and validated CD151 and ELAVL1 as best therapy response marker for TAU in TNBC. These findings provide new insight into repurposing antiviral drug TAU for treatment of metastatic and drug resistant TNBC.

LncRNA RMRP aggravates LPS-induced HK-2 cell injury and AKI mice kidney injury by upregulating COX2 protein via targeting ELAVL1

OBJECTIVES

There is emerging evidence that long non-coding RNA component of mitochondrial RNA processing endoribonuclease (lncRNA RMRP) is involved in acute kidney injury (AKI) progression, but the specific mechanism of action still requires further investigation.

METHODS

The lipopolysaccharide (LPS)-treated HK-2 cells were transfected with pcDNA-RMRP or si-RMRP, or transfected with pcDNA-ELAV like RNA binding protein 1 (ELAVL1) or si-ELAVL1, and cell viability, apoptosis, inflammatory factor secretion and oxidative stress were detected. The LPS-treated HK-2 cells were transfected with si-RMRP alone or together with pcDNA-ELAVL1, and cell behaviors were examined. The LPS-treated HK-2 cells were transfected with si-ELAVL1 alone or together with pcDNA- cyclooxygenase-2 (COX2), and the cellular changes were observed. The LPS-treated HK-2 cells were transfected with si-RMRP alone or together with pcDNA-ELAVL1, or together with pcDNA-ELAVL1 and si-COX2, and cell behaviors were examined. A mouse model of AKI was constructed using male C57BL/6 mice by the method of cecal ligation and puncture and intraperitoneal injection of LPS to explore the effect of RMRP silencing on renal injury in vivo.

RESULTS

RMRP and ELAVL1 was upregulated in LPS-treated HK-2 cells, and RMRP or ELAVL1 overexpression inhibited cell viability and promoted cell apoptosis, inflammatory factor secretion and oxidative stress, and RMRP knockdown showed the opposite effects. ELAVL1 upregulated COX2 protein expression and overexpression of COX2 reversed the promoting effects of RMRP knockdown on cell viability, as well as the inhibitory effects on cell apoptosis, inflammatory factor secretion and oxidative stress. Mechanistic findings suggested that RMRP aggravates LPS induced cell injury by activating prostaglandin E (PGE)/janus kinase-2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. We observed that knockdown of RMRP expression significantly alleviated renal tissue apoptosis, inflammatory factor secretion, and oxidative stress with AKI mice.

CONCLUSIONS

Our findings may provide a new reference for the treatment of AKI.

CERS6 antisense RNA 1 promotes colon cancer via upregulating mitochondrial calcium uniporter

BACKGROUND

Colon cancer (CC) belongs to a common cancer of digestive system. Long non-coding RNAs (lncRNAs) are dysregulated in numerous cancers and affect their development. The function of lncRNA CERS6 antisense RNA 1 (CERS6-AS1) in CC remains unclear.

MATERIALS AND METHODS

CERS6-AS1 expression in colon adenocarcinoma tissues and CC cell lines was assessed by The Cancer Genome Atlas database and quantitative real-time polymerase chain reaction analysis. The function of CERS6-AS1 in CC was analysed by 5-ethynyl-2'-deoxyuridine, colony formation, flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling, wound healing, Transwell and immunofluorescence assays. Mechanistic analyses including RNA pull down, RNA-binding protein immunoprecipitation and luciferase reporter assay revealed the interaction between RNAs.

RESULTS

CERS6-AS1 expression was aberrantly upregulated in colon adenocarcinoma tissues and CC cell lines. CERS6-AS1 knockdown inhibited CC cell malignant phenotypes and in vivo tumour growth. CERS6-AS1 served as the competing endogenous RNA of microRNA-16-5p in CC, and microRNA-16-5p inhibition partly rescued the effects of CERS6-AS1 depletion on CC development. Mitochondrial calcium uniporter was targeted by microRNA-16-5p. Mitochondrial calcium uniporter upregulation completely remedied the influence of CERS6-AS1 silencing in CC progression. Moreover, CERS6-AS1 enhanced the stability of mitochondrial calcium uniporter messenger RNA via recruiting RNA-binding protein embryonic lethal abnormal vision like 1.

CONCLUSION

CERS6-AS1 promotes the development of CC via upregulating mitochondrial calcium uniporter expression.

LINC00460 Promotes Cutaneous Squamous Cell Carcinoma Progression Through Stabilizing ELAVL1 Protein

Long intergenic noncoding ribonucleic acid (lncRNA) 460 is reportedly associated with carcinogenesis and progression in various types of cancer. However, the mechanisms underlying its action in cutaneous squamous cell carcinoma (CSCC) remain unclear. LINC00460 mRNA expression was analysed using data from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Cell growth, migration, and invasion were evaluated using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell migration and invasion assays after inducing LINC00460 knockdown. A xenograft tumour model was used to determine the effects of LINC00460 on tumour growth and metastasis in vivo. To examine the interaction between LINC00460 and ELAVL1, RNA pulldown and RNA immunoprecipitation assays were performed. LINC00460 was found to be significantly upregulated in CSCC tissues and cell lines. Functionally, LINC00460 knockdown inhibited cell proliferation, migration, and invasion in vitro. Consistent with this, when LINC00460 expression decreased, CSCC tumorigenesis and metastasis in vivo were inhibited. Mechanistically, LINC00460 binds to embryonic lethal abnormal vision like RNA binding protein 1 (ELAVL1) and enhances its stability by inhibiting the β-transducin repeats-containing protein (β-TrCP)-mediated ubiquitination of ELAVL1. Moreover, the effect of LINC00460 silencing on the proliferation, migration, and invasion of CSCC cells could be reversed by overexpressing ELAVL1. Our findings demonstrated that LINC00460 plays a critical role in regulating ELAVL1 function. This highlights the potential targets for the clinical diagnosis and treatment of CSCC.

Downregulation of ELAVL1 attenuates ferroptosis-induced neuronal impairment in rats with cerebral ischemia/reperfusion via reducing DNMT3B-dependent PINK1 methylation

BACKGROUND

Ferroptosis is a non-apoptotic form of programmed cell death and has been found in ischemic stroke. Increasing evidence revealed that ELAVL1 is associated with ferroptosis, but it remains largely unclear whether ELAVL1 is involved in ischemic stroke. Here, we aimed to investigate the biological role and mechanism of ELAVL1 in cerebral ischemia/reperfusion (I/R) injury.

METHODS

ELAVL1 shRNA were intravenously injected into rat brain, and then ischemic/reperfusion (I/R) model was constructed in rats to detect infarct volume, neurobehavioral deficit, and several ferroptosis factors (GSH, GPX4, SLC7A11, MDA, ROS, iron ion) in vivo. Oxygen-glucose deprivation/reperfusion (OGD/R) treated pheochromocytoma-12 (PC12) cells were used as in vitro models of I/R. RIP, biotin pull-down and ChIP assays was used to explore the relationship among ELAVL1, DNMT3B, and PINK1.

RESULTS

ELAVL1 was highly expressed in rat brain tissue after I/R injury. Compared with those in the I/R group, the injection of RSL3 (30 mg/kg) or ferrostatin-1 (10 mg/kg) aggravated or alleviated infarct volume, neurobehavioral impairments, and increased or decreased ferroptosis factor levels, respectively. ELAVL1 silencing ameliorated brain damage in I/R-treated rats by inhibiting ferroptosis. Moreover, ELAVL1 silencing observably facilitated cell viability, GSH content, GPX4 and SLC7A11 expression, and reduced iron ion concentration, ROS and MDA levels in OGD/R-treated PC12 cells. ELAVL1 bound with DNMT3B mRNA 3'UTR and promoted DNMT3B expression. ELAVL1 inhibited PINK1 expression through stabilizing DNMT3B mRNA and blocking DNMT3B-mediated DNA methylation of PINK1 promoter. PINK1 knockdown reversed the effects of ELAVL1 inhibition on cell viability, GSH, GPX4, SLC7A11, iron ion concentration, ROS and MDA levels in OGD/R-treated PC12 cells.

CONCLUSION

ELAVL1 plays a critical role in protecting against ferroptosis-induced cerebral I/R and subsequent brain damage via DNMT3B/PINK1 axis, thus providing a new potential target for ischemic stroke treatment.

Lactoferrin Alleviates Lipopolysaccharide-Induced Infantile Intestinal Immune Barrier Damage by Regulating an ELAVL1-Related Signaling Pathway

As the most important intestinal mucosal barrier of the main body, the innate immune barrier in intestinal tract plays especially pivotal roles in the overall health conditions of infants and young children; therefore, how to strengthen the innate immune barrier is pivotal. A variety of bioactivities of lactoferrin (LF) has been widely proved, including alleviating enteritis and inhibiting colon cancer; however, the effects of LF on intestinal immune barrier in infants and young children are still unclear, and the specific mechanism on how LF inhibits infantile enteritis by regulating immune signaling pathways is unrevealed. In the present study, we firstly performed pharmacokinetic analyses of LF in mice intestinal tissues, stomach tissues and blood, through different administration methods, to confirm the metabolic method of LF in mammals. Then we constructed in Vitro and in Vivo infantile intestinal immune barrier damage models utilizing lipopolysaccharide (LPS), and evaluated the effects of LF in alleviating LPS-induced intestinal immune barrier damage. Next, the related immune molecular mechanism on how LF exerted protective effects was investigated, through RNA-seq analyses of the mouse primary intestinal epithelial cells, and the specific genes were analyzed and screened out. Finally, the genes and their related immune pathway were validated in mRNA and protein levels; the portions of special immune cells (CD4⁺ T cells and CD8⁺ T cells) were also detected to further support our experimental results. Pharmacokinetic analyses demonstrated that the integrity of LF could reach mice stomach and intestine after oral gavage within 12 h, and the proper administration of LF should be the oral route. LF was proven to down-regulate the expression levels of inflammatory cytokines in both the primary intestinal epithelial cells and mice blood, especially LF without iron (Apo-LF), indicating LF alleviated infantile intestinal immune barrier damage induced by LPS. And through RNA-seq analyses of the mouse primary intestinal epithelial cells treated with LPS and LF, embryonic lethal abnormal vision Drosophila 1 (ELAVL1) was selected as one of the key genes, then the ELAVL1/PI3K/NF-κB pathway regulated by LF was verified to participate in the protection of infantile intestinal immune barrier damage in our study. Additionally, the ratio of blood CD4⁺/CD8⁺ T cells was significantly higher in the LF-treated mice than in the control mice, indicating that LF distinctly reinforced the overall immunity of infantile mice, further validating the strengthening bioactivity of LF on infantile intestinal immune barrier. In summary, LF was proven to alleviate LPS-induced intestinal immune barrier damage in young mice through regulating ELAVL1-related immune signaling pathways, which would expand current knowledge of the functions of bioactive proteins in foods within different research layers, as well as benefit preclinical and clinical researches in a long run.

ATF3 -activated accelerating effect of LINC00941/lncIAPF on fibroblast-to-myofibroblast differentiation by blocking autophagy depending on ELAVL1/HuR in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by lung scarring and has no effective treatment. Fibroblast-to-myofibroblast differentiation and myofibroblast proliferation and migration are major clinical manifestations of this disease; hence, blocking these processes is a practical treatment strategy. Here, highly upregulated LINC00941/lncIAPF was found to accelerate pulmonary fibrosis by promoting fibroblast-to-myofibroblast differentiation and myofibroblast proliferation and migration. Assay for transposase-accessible chromatin using sequencing and chromatin immunoprecipitation experiments elucidated that histone 3 lysine 27 acetylation (H3K27ac) activated the chromosome region opening in the LINC00941 promoter. As a consequence, the transcription factor ATF3 (activating transcription factor 3) bound to this region, and LINC00941 transcription was enhanced. RNA affinity isolation, RNA immunoprecipitation (RIP), RNase-RIP, half-life analysis, and ubiquitination experiments unveiled that LINC00941 formed a RNA-protein complex with ELAVL1/HuR (ELAV like RNA binding protein 1) to exert its pro-fibrotic function. Dual-fluorescence mRFP-GFP-MAP1LC3/LC3 (microtubule associated protein 1 light chain 3) adenovirus monitoring technology, human autophagy RT² profiler PCR array, and autophagic flux revealed that the LINC00941-ELAVL1 axis inhibited autophagosome fusion with a lysosome. ELAVL1 RIP-seq, RIP-PCR, mRNA stability, and rescue experiments showed that the LINC00941-ELAVL1 complex inhibited autophagy by controlling the stability of the target genes EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit), STAT1 (signal transducer and activators of transcription 1) and FOXK1 (forkhead box K1). Finally, the therapeutic effect of LINC00941 was confirmed in a mouse model and patients with IPF. This work provides a therapeutic target and a new effective therapeutic strategy related to autophagy for IPF.Abbreviations: ACTA2/a-SMA: actin alpha 2, smooth muscle; ATF3: activating transcription factor 3; ATG: autophagy related; Baf-A1: bafilomycin A₁; BLM: bleomycin; CDKN: cyclin dependent kinase inhibitor; CLN3: CLN3 lysosomal/endosomal transmembrane protein, battenin; COL1A: collagen type I alpha; COL3A: collagen type III alpha; CXCR4: C-X-C motif chemokine receptor 4; DRAM2: DNA damage regulated autophagy modulator 2; ELAVL1/HuR: ELAV like RNA binding protein 1; EZH2: enhancer of zeste 2 polycomb repressive complex 2 subunit; FADD: Fas associated via death domain; FAP/FAPα: fibroblast activation protein alpha; FOXK1: forkhead box K1; FVC: forced vital capacity; GABARAP: GABA type A receptor-associated protein; GABARAPL2: GABA type A receptor associated protein like 2; IGF1: insulin like growth factor 1; IPF: idiopathic pulmonary fibrosis; LAMP: lysosomal associated membrane protein; lncRNA: long noncoding RNA; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NPC1: NPC intracellular cholesterol transporter 1; RGS: regulator of G protein signaling; RPLP0: ribosomal protein lateral stalk subunit P0; ROC: receiver operating characteristic; S100A4: S100 calcium binding protein A4; SQSTM1/p62: sequestosome 1; STAT1: signal transducers and activators of transcription 1; TGFB1/TGF-β1: transforming growth factor beta 1; TNF: tumor necrosis factor; UIP: usual interstitial pneumonia; ULK1: unc-51 like autophagy activating kinase 1; VIM: vimentin.

A novel LINC00943/miR-671-5p/ELAVL1 ceRNA crosstalk regulates MPP+ toxicity in SK-N-SH cells

The competing endogenous RNA (ceRNA) activity of long non-coding RNAs (lncRNAs) has profound effects in pathological disorders, including Parkinson's disease. Here, we focused on the LINC00943-mediated ceRNA network for the regulation of LINC00943 in MPP+ toxicity in SK-N-SH cells. SK-N-SH cells were exposed to 1-methyl-4-phenylpyridinium (MPP+). LINC00943, miR-671-5p and ELAV like RNA binding protein 1 (ELAVL1) were quantified by real-time quantitative PCR (RT-qPCR) or western blot. Cell viability and apoptosis were gauged by Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Direct relationship between miR-671-5p and LINC00943 or ELAVL1 was confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Our data validated that LINC00943 regulated MPP+-evoked injury in SK-N-SH cells. LINC00943 regulated miR-671-5p expression by binding to miR-671-5p. Moreover, miR-671-5p was identified as a molecular mediator of LINC00943 in regulating SK-N-SH cell injury induced by MPP+. MiR-671-5p targeted and inhibited ELAVL1, and miR-671-5p-mediated inhibition of ELAVL1 impacted MPP+-evoked SK-N-SH cell injury. Furthermore, LINC00943 involved the post-transcriptional regulation of ELAVL1 through miR-671-5p competition. Our present study has established a novel mechanism, the LINC00943/miR-671-5p/ELAVL1 ceRNA crosstalk, for the regulation of LINC00943 on MPP+ toxicity in SK-N-SH cells.

The RNA-Binding Protein ELAVL1 Regulates Hepatitis B Virus Replication and Growth of Hepatocellular Carcinoma Cells

Previous RNA immunoprecipitation followed by proteomic approaches successfully demonstrated that Embryonic Lethal, Abnormal Vision, Drosophila-Like 1 (ELAVL1) interacts with hepatitis B virus (HBV)-derived RNAs. Although ELAVL family proteins stabilize AU-rich element (ARE)-containing mRNAs, their role in HBV transcription remains unclear. This study conducted loss-of-function assays of ELAVL1 for inducible HBV-replicating HepAD38 cells and HBx-overexpressed HepG2 cells. In addition, clinicopathological analyses in primary hepatocellular carcinoma (HCC) surgical samples were also conducted. Lentivirus-mediated short hairpin RNA knockdown of ELAVL1 resulted in a decrease in both viral RNA transcription and production of viral proteins, including HBs and HBx, probably due to RNA stabilization by ELAVL1. Cell growth of HepAD38 cells was more significantly impaired in ELAVL1-knockdown than those in the control group, with or without HBV replication, indicating that ELAVL1 is involved in proliferation by factors other than HBV-derived RNAs. Immunohistochemical analyses of 77 paired HCC surgical specimens demonstrated that diffuse ELAVL1 expression was detected more frequently in HCC tissues (61.0%) than in non-tumor tissues (27.3%). In addition, the abundant expression of ELAVL1 tended to affect postoperative recurrence in HBV-related HCC patients. In conclusion, ELAVL1 contributes not only to HBV replication but also to HCC cell growth. It may be a potent therapeutic target for HBV-related HCC treatment.

Circ_0060551 promotes the migration and invasion of cervical cancer by Up-regulating TPD52

PROBLEM

Cervical cancer has been recognized as the second most common cancer in women worldwide. Previous studies have reported that some circular RNAs (circRNAs) can influence the progression of cervical cancer. However, more researches are still required to unveil the underlying mechanism of how circRNAs regulate the progression of such cancer. We aimed at unveiling the mechanism of how circ_0060551 effected the progression of cervical cancer.

METHOD OF STUDY

RT-qPCR and western blot assays were used to detect the expression and protein levels. Mechanism experiments were conducted to investigate the relationship among circ_0060551, TPD52, miR-520a-5p and ELAVL1. Rescue assays were mainly carried out to verify how circ_0060551 influenced the migration and invasion of cervical cancer cells.

RESULTS

According to the results, circ_0060551 was up-regulated in cervical cancer cells and could promote the migration and invasion of cells via TPD52. In addition, circ_0060551 could up-regulate TPD52 expression through a ceRNA model to target miR-520a-5p. Moreover, circ_0060551 could stabilize the mRNA expression of TPD52 via recruiting ELAVL1.

CONCLUSION

Our study proved that circ_0060551 could promote the migration and invasion of cervical cancer cells. This article is protected by copyright. All rights reserved.

Role of Human Antigen R (HuR) in the Regulation of Pulmonary ACE2 Expression

Patients with COPD may be at an increased risk for severe illness from COVID-19 because of ACE2 upregulation, the entry receptor for SARS-CoV-2. Chronic exposure to cigarette smoke, the main risk factor for COPD, increases pulmonary ACE2. How ACE2 expression is controlled is not known but may involve HuR, an RNA binding protein that increases protein expression by stabilizing mRNA. We hypothesized that HuR would increase ACE2 protein expression. We analyzed scRNA-seq data to profile ELAVL1 expression in distinct respiratory cell populations in COVID-19 and COPD patients. HuR expression and cellular localization was evaluated in COPD lung tissue by multiplex immunohistochemistry and in human lung cells by imaging flow cytometry. The regulation of ACE2 expression was evaluated using siRNA-mediated knockdown of HuR. There is a significant positive correlation between ELAVL1 and ACE2 in COPD cells. HuR cytoplasmic localization is higher in smoker and COPD lung tissue; there were also higher levels of cleaved HuR (CP-1). HuR binds to ACE2 mRNA but knockdown of HuR does not change ACE2 protein levels in primary human lung fibroblasts (HLFs). Our work is the first to investigate the association between ACE2 and HuR. Further investigation is needed to understand the mechanistic underpinning behind the regulation of ACE2 expression.

LncRNA MIR99AHG mediated by FOXA1 modulates NOTCH2/Notch signaling pathway to accelerate pancreatic cancer through sponging miR-3129-5p and recruiting ELAVL1

Background

Pancreatic cancer (PCa) is a fatal malignancy with poor prognosis, high recurrence and mortality. Substantial reports have suggested long non-coding RNAs (lncRNAs) are implicated in development of numerous malignant tumors, and PCa is included. However, the correlation between novel lncRNA mir-99a-let-7c cluster host gene (MIR99AHG) and PCa remains elusive and needs to be deeply investigated.

Methods

In this study, we firstly used RT-qPCR to examine MIR99AHG expression. Functional assays were implemented for determination of the role of MIR99AHG in PCa cells. Mechanism experiments were designed and carried out for exploring the regulatory mechanism involving MIR99AHG.

Results

MIR99AHG was distinctly overexpressed in PCa cell lines. MIR99AHG deficiency abrogated PCa cell proliferation, migration and invasion. Moreover, MIR99AHG up-regulation was induced by transcription factor forkhead box A1 (FOXA1). Furthermore, MIR99AHG modulated notch receptor 2 (NOTCH2) expression and stimulated Notch signaling pathway through sequestering microRNA-3129-5p (miR-3129-5p) and recruiting ELAV like RNA binding protein 1 (ELAVL1).

Conclusions

Altogether, the exploration of FOXA1/MIR99AHG/miR-3129-5p/ELAVL1/NOTCH2 axis in the progression of PCa might provide a meaningful revelation for PCa diagnosis and treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02189-z.

Exosomal lncRNA FOXD3-AS1 upregulates ELAVL1 expression and activates PI3K/Akt pathway to enhance lung cancer cell proliferation, invasion, and 5-fluorouracil resistance

Long non-coding RNA (lncRNA) FOXD3-AS1 expression is upregulated in lung cancer; however, its effect and mechanism on 5-fluorouracil (5-FU) resistance remain unclear. In this study, we determined the effects of FOXD3-AS1-enriched exosomes derived from lung cancer cells on the proliferation, invasion, and 5-FU resistance of lung cancer cells. Online bioinformatics database analysis showed that FOXD3-AS1 was upregulated in lung cancer progression. Real-time quantitative PCR results confirmed that FOXD3-AS1 expression was upregulated in lung cancer tissues and cell lines, and FOXD3-AS1 was greatly enriched in lung cancer cell-derived exosomes. ELAV-like RNA-binding protein 1 (ELAVL1) was identified as an RNA-binding protein of FOXD3-AS1. The lung cancer cell-derived exosomes promoted A549 cell proliferation and invasion and inhibited apoptosis caused by 5-FU, and transfection of si-FOXD3-AS1 or si-ELAVL1 in exosome-incubated A549 cells reversed these effects. Moreover, exosome-incubated A549 cells were co-transfected with si-FOXD3-AS1 and pcDNA-ELAVL1, showing the same cell proliferation, invasion, and 5-FU resistance as those of A549 cells treated with lung cancer cell-derived exosomes alone. Mechanistic studies identified that lung cancer cell-derived exosomes activated the PI3K/Akt pathway, and transfection of si-FOXD3-AS1 or treatment with the PI3K inhibitor LY294002 reversed the activation of the PI3K/Akt axis induced by exosomes. In conclusion, our study revealed that lung cancer cell-derived exosomal FOXD3-AS1 upregulated ELAVL1 expression and activated the PI3K/Akt pathway to promote lung cancer progression. Our findings provide a new strategy for lung cancer treatment.

FAM49B promotes breast cancer proliferation, metastasis, and chemoresistance by stabilizing ELAVL1 protein and regulating downstream Rab10/TLR4 pathway

BACKGROUND

Breast cancer (BC) is one of the most common cancers and the leading cause of death in women. Previous studies have demonstrated that FAM49B is implicated in several tumor progression, however, the role and mechanism of FAM49B in BC remain to be explored. Therefore, in this study, we aimed to systematically study the role of FAM49B in the proliferation, metastasis, apoptosis, and chemoresistance of BC, as well as the corresponding molecular mechanisms and downstream target.

METHODS

The ONCOMINE databases and Kaplan-Meier plotter databases were analyzed to find FAM49B and its prognostic values in BC. FAM49B expression in BC and adjacent non-tumor tissues was detected by western blot and IHC. Kaplan-Meier analysis was used to identify the prognosis of BC patients. After FAM49B knockdown in MCF-7 and MDA-MB-231 cells, a combination of co-immunoprecipitation, MTT, migration, and apoptosis assays, nude mouse xenograft tumor model, in addition to microarray detection and data analysis was used for further mechanistic studies.

RESULTS

In BC, the results showed that the expression level of FAM49B was significantly higher than that in normal breast tissue, and highly expression of FAM49B was significantly positively correlated with tumor volume, histological grade, lymph node metastasis rate, and poor prognosis. Knockdown of FAM49B inhibited the proliferation and migration of BC cells in vitro and in vivo. Microarray analysis revealed that the Toll-like receptor signaling pathway was inhibited upon FAM49B knockdown. In addition, the gene interaction network and downstream protein validation of FAM49B revealed that FAM49B positively regulates BC cell proliferation and migration by promoting the Rab10/TLR4 pathway. Furthermore, endogenous FAM49B interacted with ELAVL1 and positively regulated Rab10 and TLR4 expression by stabilizing ELAVL1. Moreover, mechanistic studies indicated that the lack of FAM49B expression in BC cells conferred more sensitivity to anthracycline and increased cell apoptosis by downregulating the ELAVL1/Rab10/TLR4/NF-κB signaling pathway.

CONCLUSION

These results demonstrate that FAM49B functions as an oncogene in BC progression, and may provide a promising target for clinical diagnosis and therapy of BC.

Long Non-coding RNA LINC01119 Promotes Neuropathic Pain by Stabilizing BDNF Transcript

Neuropathic pain (NP) is caused by primary injury or dysfunction of the peripheral and the central nervous system. Long non-coding RNAs were critical regulators involved in nervous system diseases, however, the precise regulatory mechanism remains unclear. This study aims to uncover the essential role of LINC01119 in NP progression and further clarify the underlying regulatory mechanism at post-transcriptional level. LINC01119 was significantly upregulated in rats of spare nerve injury (SNI) group compared to sham group. Functionally, silencing of LINC01119 significantly alleviated the neuropathic pain-induced hypersensitivity and reduced the increase in IL-6, IL-1β, and TNF-α caused by SNI. Mechanistically, Brain-derived neurotrophic factor (BDNF) was identified as the functional target of LINC01119. Besides, an RNA binding protein, ELAVL1 could directly interact with LINC01119, and this formed LINC01119- ELAVL1 complex binds to BDNF mRNA, strengthening its RNA stability and increasing the expression level of BDNF at both transcript and protein levels. Clinically, serum LINC01119 was verified as a promising diagnostic biomarker for NP patients. LINC01119 induces NP progression via binding with ELAVL1 and increasing BDNF mRNA stability and expression level. Therefore, LINC01119 may serve as a promising diagnostic marker and therapeutic target for NP treatment.

CIRBP promotes ferroptosis by interacting with ELAVL1 and activating ferritinophagy during renal ischaemia-reperfusion injury

Renal ischaemia-reperfusion (IR) is a major cause of acute kidney injury (AKI). Cold-inducible RNA-binding protein (CIRBP) may contribute to AKI because its deficiency protects against renal IR injury in a mechanism believed to involve ferroptosis. We aimed to investigate whether ferroptosis is associated with CIRBP-mediated renal damage. The differential expression of CIRBP was examined in tubular epithelial (HK2) cells during hypoxia-reoxygenation (HR) or in response to erastin, an inducer of ferroptosis. CIRBP expression was increased in response to HR or erastin in HK2 cells but the silencing of CIRBP inhibited HR and erastin-induced ferroptosis together with ferritinophagy. We discovered an interaction between CIRBP and ELAVL1 using STRING software, which was verified through co-immunoprecipitation and fluorescence colocalization assays. We found that ELAVL1 is a critical regulator in the activation of ferritinophagy and the promotion of ferroptosis. HR or erastin also induced the expression of ELAVL1. An autophagy inhibitor (hydroxychloroquine) or si-ELAVL1 transfection reversed CIRBP-enhanced ferritinophagy activation and ferroptosis in HK2 cells under HR. Injection of anti-CIRBP antibody into a mouse model of IR inhibited ferroptosis and decreased renal IR injury in vivo. In summary, our results provide evidence that ferritinophagy-mediated ferroptosis could be responsible for CIRBP-enhanced renal IR injury.

Single-nucleotide polymorphism rs4142441 and MYC co-modulated long non-coding RNA OSER1-AS1 suppresses non-small cell lung cancer by sequestering ELAVL1

Single‐nucleotide polymorphisms (SNP) and long non‐coding RNAs (lncRNAs) have been involved in the process of lung cancer. Following clues given by lung cancer risk‐associated SNP, we aimed to find novel functional lncRNAs as candidate targets in lung cancer. We identified a lncRNA Oxidative Stress Responsive Serine Rich 1 Antisense RNA 1 (OSER1‐AS1) through a lung cancer risk‐associated SNP rs4142441. OSER1‐AS1 was down‐regulated in tumor tissue and its low expression was significantly associated with poor overall survival among non‐smokers in non‐small cell lung cancer (NSCLC) patients. Gain‐ and loss‐of‐function studies showed that OSER1‐AS1 acted as a tumor suppressor by inhibiting lung cancer cell growth, migration and invasion in vitro. Xenograft tumor assays and a metastasis mouse model confirmed that OSER1‐AS1 suppressed tumor growth and metastasis in vivo. The promoter of OSER1‐AS1 was repressed by MYC, and the 3′‐end of OSER1‐AS1 was competitively targeted by microRNA hsa‐miR‐17‐5p and RNA‐binding protein ELAVL1. Our results indicated that OSER1‐AS1 exerted tumor‐suppressive functions by acting as an ELAVL1 decoy to keep it away from its target mRNAs. Our findings characterized OSER1‐AS1 as a new tumor‐suppressive lncRNA in NSCLC, suggesting that OSER1‐AS1 may be suitable as a potential biomarker for prognosis, and a potential target for treatment.

ELAVL1 primarily couples mRNA stability with the 3' UTRs of interferon-stimulated genes

Upon pathogen detection, the innate immune system triggers signaling events leading to upregulation of pro-inflammatory and anti-microbial mRNA transcripts. RNA-binding proteins (RBPs) interact with these critical mRNAs and regulate their fates at the post-transcriptional level. One such RBP is ELAVL1. Although significant progress has been made in understanding how embryonic lethal vision-like protein 1 (ELAVL1) regulates mRNAs, its target repertoire and binding distribution within an immunological context remain poorly understood. We overlap four high-throughput approaches to define its context-dependent targets and determine its regulatory impact during immune activation. ELAVL1 transitions from binding overwhelmingly intronic sites to 3′ UTR sites upon immune stimulation of cells, binding previously and newly expressed mRNAs. We find that ELAVL1 mediates the RNA stability of genes that regulate pathways essential to pathogen sensing and cytokine production. Our findings reveal the importance of examining RBP regulatory impact under dynamic transcriptomic events to understand their post-transcriptional regulatory roles within specific biological circuitries.

Rothamel et al. show that upon immune activation, the RNA-binding protein ELAVL1 accumulates in the cytoplasm and redistributes from introns to mRNA 3′ UTRs. 3′ UTR binding confers enrichment and transcript stability. Many top-ranking transcripts are interferon-stimulated genes (ISGs), indicating that ELAVL1 is a positive regulator of an innate immune response.

Human antigen R promotes lung fibroblast differentiation to myofibroblasts and increases extracellular matrix production

Idiopathic pulmonary fibrosis (IPF) is a disease of progressive scarring caused by excessive extracellular matrix (ECM) deposition and activation of α-SMA-expressing myofibroblasts. Human antigen R (HuR) is an RNA binding protein that promotes protein translation. Upon translocation from the nucleus to the cytoplasm, HuR functions to stabilize messenger RNA (mRNA) to increase protein levels. However, the role of HuR in promoting ECM production, myofibroblast differentiation, and lung fibrosis is unknown. Human lung fibroblasts (HLFs) treated with transforming growth factor β1 (TGF-β1) showed a significant increase in translocation of HuR from the nucleus to the cytoplasm. TGF-β-treated HLFs that were transfected with HuR small interfering RNA had a significant reduction in α-SMA protein as well as the ECM proteins COL1A1, COL3A, and FN1. HuR was also bound to mRNA for ACTA2, COL1A1, COL3A1, and FN. HuR knockdown affected the mRNA stability of ACTA2 but not that of the ECM genes COL1A1, COL3A1, or FN. In mouse models of pulmonary fibrosis, there was higher cytoplasmic HuR in lung structural cells compared to control mice. In human IPF lungs, there was also more cytoplasmic HuR. This study is the first to show that HuR in lung fibroblasts controls their differentiation to myofibroblasts and consequent ECM production. Further research on HuR could assist in establishing the basis for the development of new target therapy for fibrotic diseases, such as IPF.

Long non-coding RNA BCAR4 aggravated proliferation and migration in esophageal squamous cell carcinoma by negatively regulating p53/p21 signaling pathway

Long non-coding RNA breast cancer antiestrogen resistance 4 (lncRNA BCAR4) is an independent factor on the survival prognosis of patients with multiple cancers. However, the role of lncRNA BCAR4 in esophageal squamous cell cancer (ESCC) remains unknown. Here, we unraveled that lncRNA BCAR4 was upregulated in ESCC and predicted poor prognosis. Functionally, lncRNA BCAR4 knockdown induced cell apoptosis and G1/S arrest, while inhibited cell proliferation and migration in vitro; conversely, overexpressing lncRNA BCAR4 promoted proliferation and metastasis. Mechanistically, lncRNA BCAR4 sponged miR-139-3p to upregulate ELAVL1, thereby inhibiting p53/p21 pathway in ESCC cells. In conclusion, lncRNA BCAR4 promotes ESCC tumorigenesis via regulating p53/p21 signaling pathway and develops a brand-new biomarker and medicine target for ESCC.

ELAVL1 is transcriptionally activated by FOXC1 and promotes ferroptosis in myocardial ischemia/reperfusion injury by regulating autophagy

Aims

Myocardial ischemia is the most common form of cardiovascular disease and the leading cause of morbidity and mortality. Understanding the mechanisms is very crucial for the development of effective therapy. Therefore, this study aimed to investigate the functional roles and mechanisms by which ELAVL1 regulates myocardial ischemia and reperfusion (I/R) injury.

Methods

Mouse myocardial I/R model and cultured myocardial cells exposed to hypoxia/reperfusion (H/R) were used in this study. Features of ferroptosis were evidenced by LDH activity, GPx4 activity, cellular iron, ROS, LPO, and GSH levels. The expression levels of autophagy markers (Beclin-1, p62, LC3), ELAVL1 and FOXC1 were measured by qRT-PCR, immunostaining and western blot. RIP assay, biotin-pull down, ChIP and dual luciferase activity assay were employed to examine the interactions of ELAVL1/Beclin-1 mRNA and FOXC1/ELAVL1 promoter. CCK-8 assay was used to examine viability of cells. TTC staining was performed to assess the myocardial I/R injury.

Results

Myocardial I/R surgery induced ferroptosis and up-regulated ELAVL1 level. Knockdown of ELAVL1 decreased ferroptosis and ameliorated I/R injury. Si-ELAVL1 repressed autophagy and inhibition of autophagy by inhibitor suppressed ferroptosis and I/R injury in myocardial cells. Increase of autophagy could reverse the effects of ELAVL1 knockdown on ferroptosis and I/R injury. ELAVL1 directly bound with and stabilized Beclin-1 mRNA. Furthermore, FOXC1 bound to ELAVL1 promoter region and activated its transcription upon H/R exposure.

Conclusion

FOXC1 transcriptionally activated ELAVL1 may promote ferroptosis during myocardial I/R by modulating autophagy, leading to myocardial injury. Inhibition of ELAVL1-mediated autophagic ferroptosis would be a new viewpoint in the treatment of myocardial I/R injury.

Exosomal long noncoding RNA AGAP2-AS1 regulates trastuzumab resistance via inducing autophagy in breast cancer

Trastuzumab has been widely used for treatment of HER-2-positive breast cancer patients, however, the clinical response has been restricted due to emergence of resistance. Recent studies indicate that long noncoding RNA AGAP2-AS1 (lncRNA AGAP2-AS1) plays an important role in cancer resistance. However, the precise regulatory function and therapeutic potential of AGAP2-AS1 in trastuzumab resistance is still not defined. In this study, we sought to reveal the essential role of AGAP2-AS1 in trastuzumab resistance. Our results suggest that AGAP2-AS1 disseminates trastuzumab resistance via packaging into exosomes. Exosomal AGAP2-AS1 induces trastuzumab resistance via modulating ATG10 expression and autophagy activity. Mechanically, AGAP2-AS1 is associated with ELAVL1 protein, and the AGAP2-AS1-ELAVL1 complex could directly bind to the promoter region of ATG10, inducing H3K27ac and H3K4me3 enrichment, which finally activates ATG10 transcription. AGAP2-AS1-targeting antisense oligonucleotides (ASO) substantially increased trastuzumab-induced cytotoxicity. Clinically, increased expression of serum exosomal AGAP2-AS1 was associate with poor response to trastuzumab treatment. In conclusion, exosomal AGAP2-AS1 increased trastuzumab resistance via promoting ATG10 expression and inducing autophagy. Therefore, AGAP2-AS1 may serve as predictive biomarker and therapeutic target for HER-2+ breast cancer patients.

Synergistic regulation of Rgs4 mRNA by HuR and miR-26/RISC in neurons

The negative regulator of G-protein signalling 4 (Rgs4) is linked to several neurologic diseases, e.g. schizophrenia, addiction, seizure and pain perception. Consequently, Rgs4 expression is tightly regulated, resulting in high mRNA and protein turnover. The post-transcriptional control of gene expression is mediated via RNA-binding proteins (RBPs) that interact with mRNAs in a combinatorial fashion. Here, we show that in neurons the RBP HuR reduces endogenous Rgs4 expression by destabilizing Rgs4 mRNA. Interestingly, in smooth muscle cells, Rgs4 is stabilized by HuR, indicating tissue-dependent differences in HuR function. Using in vitro RNA-based pulldown experiments, we identify the functional AU-rich element (ARE) within the Rgs4 3ʹ-UTR that is recognized and bound by HuR. Bioinformatic analysis uncovered that this ARE lies within a highly conserved area next to a miR-26 binding site. We find that the neuronal-enriched miR-26 negatively influences Rgs4 expression in neurons. Further, HuR and miR-26 act synergistically in fluorescent reporter assays. Together, our data suggest a regulatory mechanism, in which an RBP selectively destabilizes a target mRNA in cooperation with a miRNA and the RISC machinery.

MicroRNA-324-5p affects the radiotherapy response of cervical cancer via targeting ELAV-like RNA binding protein 1

Cervical cancer (CC) seriously threatens the health of women. Radiation therapy (RT) is the major treatment for CC. However, the recurrent CC can acquire resistance to RT. Thus, it is necessary to find a new method for reversing RT resistance in CC. It has been reported that miR-324-5p can suppress the progression of multiple cancers. However, whether it can reverse resistance to RT in CC remains unclear. qRT-PCR and Western blotting were used to detect gene and protein expression in CC cells, respectively. Cell proliferation was tested by CCK-8 assay and colony formation assay. In addition, cell apoptosis was detected by flow cytometry. Transwell assays were performed to detect cell migration. Dual luciferase reporter assay and TargetScan were used to explore the targets of microRNA-324-5p (miR-324-5p). MiR-324-5p was downregulated in CC cells. Overexpression of miR-324-5p sensitized CC cells to RT. In addition, miR-324-5p mimics significantly induced apoptosis and inhibits the migration of CC cells in the presence of ¹³⁷ Cs ionizing radiation. Furthermore, miR-324-5p sensitized CC cells to ionizing radiation by targeting ELAV-like RNA binding protein 1 (ELAVL1). MiR-324-5p overexpression affects the radiotherapy response of CC by targeting ELAVL1, which may serve as a new target for the treatment of CC.

Stabilization of oncogenic transcripts by the IGF2BP3/ELAVL1 complex promotes tumorigenicity in colorectal cancer

The expression of RNA-binding proteins (RBPs) is dysregulated in colorectal cancer (CRC) and in other types of cancer. Among the RBPs, the insulin-like growth factor-2 messenger RNA binding protein (IGF2BP1-3) family is involved in the development of the colon and the progression of CRC. However, the regulation of mRNA fate by IGF2BP3 in CRC remains less well understood. Here, we show that IGF2BP3 interacts with ELAVL1 to coregulate a cohort of genes involved in the cell cycle and cell proliferation. Mechanistically, recognition of these mRNAs by the IGF2BP3/ELAVL1 complex leads to prolonged half-lives of the mRNA molecules and increased expression of the target genes, thereby driving CRC cell proliferation. Interestingly, knockdown of either IGF2BP3 or ELAVL1 impairs the IGF2BP3/ELAVL1 complex-enhanced mRNA stability, suggesting a functional interdependency between IGF2BP3 and ELAVL1 in CRC. Our findings reveal the molecular mechanism by which IGF2BP3 regulates mRNA stability and identify the cooperativity of the IGF2BP3/ELAVL1 complex as a novel therapeutic target in CRC.

Angustoline Inhibited Esophageal Tumors Through Regulating LKB1/AMPK/ELAVL1/LPACT2 Pathway and Phospholipid Remodeling

Esophageal cancer is a type of gastrointestinal carcinoma and is among the 10 most common causes of cancer death worldwide. However, the specific mechanism and the biomarkers in the proliferation and metastasis of esophageal tumors are still unclear. Therefore, the development of several natural products which could inhibit esophageal tumors deserve attention. In the present study, different sources of cancer cells were used to select the sensitive cell line (esophageal cancer cell KYSE450) and the proper dose of angustoline, which were utilized in the following cell viability, migration and invasion assays. Then the lipidomic detection of clinical samples (tissue and blood plasma) from esophageal cancer patients was performed, to screen out the specific phospholipid metabolites [PC (16:0/18:1) and LPC (16:0)]. Considering lysophosphatidylcholine acyltransferase 2 (LPCAT2) was tightly relative with phospholipids conversion, serine/threonine-protein kinase 11 (LKB1), 5'-monophosphate (AMP)-activated protein kinase (AMPK) and embryonic lethal, and abnormal vision, drosophila-like 1 (ELAVL1) were investigated, to evaluate their expression levels in esophageal tumor tissue and KYSE450 cells. Additionally, KYSE450 tumor bearing mouse model was constructed, the role of angustoline in inhibiting esophageal tumors through regulating LKB1/AMPK/ELAVL1/LPCAT2 pathway was validated, and found that the conversion from LPC (16:0) to PC (16:0/18:1) was blocked by angustoline in some degree. The above results for the first time proved that angustoline suppressed esophageal tumors through activating LKB1/AMPK and inhibiting ELAVL1/LPCAT2, which consequently blocked phospholipid remodeling from LPC (16:0) to PC (16:0/18:1).

LncRNA SNHG7 promotes the proliferation of nasopharyngeal carcinoma by miR-514a-5p/ELAVL1 axis

Background

Nasopharyngeal carcinoma (NPC), with distinct geographical distribution, has gathered public attention. Despite that radiotherapy and chemotherapy are applied to treat NPC, cell metastasis still cannot be avoided. Numerous works have elucidated that lncRNAs are essential players in the development of multiple cancers. LncRNA SNHG7 has been reported as a contributing factor in the occurrence of certain cancers, but its mechanism in NPC deserves further investigation. The purpose of the study is to figure out the role and molecular regulation mechanism of SNHG7 in NPC.

Methods

The role of SNHG7 in NPC was verified by CCK-8, colony formation, EdU staining, western blot and capase-3 assays. The interactions between SNHG7/ELAVL1 and miR-514a-5p were confirmed by RNA pull down, RT-qPCR, RIP and luciferase reporter assays.

Results

SNHG7 was upregulated in NPC cells, and absence of SNHG7 suppressed cell proliferation as well as promoted cell apoptosis in NPC. Furthermore, SNHG7 was confirmed to bind with miR-514a-5p and negatively modulate miR-514a-5p expression. Besides, miR-514a-5p was found to be able to bind with ELAVL1 and negatively regulate ELAVL1 mRNA and protein expressions. In the end, rescue assays demonstrated that the miR-514a-5p deficiency restored the NPC progression inhibited by SNHG7 silence, and ELAVL1 partly counteracted the restoration caused by miR-514a-5p inhibitor in HNE1 cells.

Conclusions

LncRNA SNHG7 promotes the proliferation and migration of nasopharyngeal carcinoma by miR-514a-5p/ ELAVL1 axis.

ZEB1 induced-upregulation of long noncoding RNA ZEB1-AS1 facilitates the progression of triple negative breast cancer by binding with ELAVL1 to maintain the stability of ZEB1 mRNA

Triple-negative breast cancer (TNBC) is one of the malignant type of breast cancer. Previous study indicated that long noncoding RNA (lncRNA) ZEB1-AS1 was associated with the progression of several cancers. However, its underlying molecular mechanism in TNBC remains to be elucidated. In this study, ZEB1-AS1 expression was boosted in TNBC tissues and cell lines according to reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Inhibition of ZEB1-AS1 suppressed cell proliferation, migration, invasion, and promoted cell apoptosis in TNBC. Moreover, ZEB1-AS1 positively regulated ZEB1 expression. RT-qPCR disclosed ZEB1 expression was elevated in TNBC tissues and ZEB1 silence blocked TNBC progression. RNA pull-down and RNA immunoprecipitation assays revealed ZEB1-AS1 and ZEB1 both could bind with ELAVL1. ZEB1-AS1 maintained ZEB1 messenger RNA (mRNA) stability by binding with ELAVL1. In addition chromatin, immunoprecipitation and luciferase reporter assays confirmed that ZEB1 could bind with ZEB1-AS1 promoter and promoted ZEB1-AS1 expression. Rescue assays manifested ZEB1 overexpression could abolish the inhibitory effect caused by ZEB1-AS1 inhibition on TNBC progression. To sum up, ZEB1 induced-upregulation of ZEB1-AS1 maintained the stability of ZEB1 mRNA by binding with ELAVL1, which formed a feedback loop to facilitate TNBC progression. These findings might provide a new target for TNBC treatment.

LncRNA HOXB-AS1 promotes cell growth in multiple myeloma via FUT4 mRNA stability by ELAVL1

Multiple myeloma (MM) is defined as the second most common hematological tumor in the globe. Long noncoding RNAs (lncRNAs) have been reported to play stimulative or suppressive role in the progression of different carcinomas. The investigation of lncRNAs in MM is still inadequate. LncRNA HOXB cluster antisense RNA 1 (HOXB-AS1) was once revealed to facilitate glioma progression by affecting cellular activities of glioma cells. However, whether HOXB-AS1 participates in the development of MM still remains an enigma. In this study, we unveiled that HOXB-AS1 was highly expressed in MM and loss-of-function assays certified that HOXB-AS1 obstruction suppressed MM cell proliferation, and stimulated cell apoptosis. In addition, HOXB-AS1 could modulate fucosyltransferase 4 (FUT4) and FUT4-mediated Wnt/β-catenin pathway. In subsequence, it was observed from mechanism assays that HOXB-AS1 enhanced the interaction between ELAVL1 and FUT4 so as to stabilize FUT4 messenger RNA. In the end, rescue experiments affirmed that HOXB-AS1 affected the cell growth through FUT4 in MM. In conclusion, the whole modulation mechanism of HOXB-AS1/ELAVL1/FUT4 axis in MM was validated in this study, which suggested that HOXB-AS1 might function as a powerful and promising therapeutic biomarker for the clinical treatment of patients with MM.

Ultra-fast conductive media for RNA electrophoretic mobility shift assays

The use of RNA electrophoretic mobility shift assays (REMSAs) for analysis of RNA-protein interactions have been limited to lengthy assay time and qualitative assessment. To vastly improve assay efficiency, feasibility and quality of data procured from REMSAs, we combine here some of the best-known labeling and electrophoretic techniques. Nucleic acid fragments are end-labeled with fluorescent tags, as opposed to the radioactive or biotin tags. The fluorescent probes may be detected directly from the electrophoresis gel, eliminating the need for cumbersome membrane transfer and immunoblotting. Modifying the REMSA protocol to include low-molarity, lithium borate conductive media and near-infrared-labeled probes allows for a reduction assay time, quantitative comparison between experimental conditions and crisp band resolution (i.e., optimized results).

HuR Reduces Radiation-Induced DNA Damage by Enhancing Expression of ARID1A

Tumor suppressor ARID1A, a subunit of the chromatin remodeling complex SWI/SNF, regulates cell cycle progression, interacts with the tumor suppressor TP53, and prevents genomic instability. In addition, ARID1A has been shown to foster resistance to cancer therapy. By promoting non-homologous end joining (NHEJ), ARID1A enhances DNA repair. Consequently, ARID1A has been proposed as a promising therapeutic target to sensitize cancer cells to chemotherapy and radiation. Here, we report that ARID1A is regulated by human antigen R (HuR), an RNA-binding protein that is highly expressed in a wide range of cancers and enables resistance to chemotherapy and radiation. Our results indicate that HuR binds ARID1A mRNA, thereby increasing its stability in breast cancer cells. We further find that ARID1A expression suppresses the accumulation of DNA double-strand breaks (DSBs) caused by radiation and can rescue the loss of radioresistance triggered by HuR inhibition, suggesting that ARID1A plays an important role in HuR-driven resistance to radiation. Taken together, our work shows that HuR and ARID1A form an important regulatory axis in radiation resistance that can be targeted to improve radiotherapy in breast cancer patients.

Small nucleolar RNA host gene 3 facilitates cell proliferation and migration in oral squamous cell carcinoma via targeting nuclear transcription factor Y subunit gamma

Oral squamous cell carcinoma (OSCC) has been reported to be the most common oral carcinoma. Emerging evidence has revealed the key role that long noncoding RNAs (lncRNAs) play in numerous malignancies, including OSCC. LncRNA small nucleolar RNA host gene 3 (SNHG3) has been reported as an oncogenic factor in some cancers. Nonetheless, the role of SNHG3 in OSCC has never been clarified. In this study, we analyzed the expression patterns of SNHG3 in OSCC through quantitative real-time polymerase chain reaction. It was revealed that the expression level of SNHG3 was remarkably elevated in OSCC cell lines compared with the nontumor cell line. It was demonstrated by functional experiments that SNHG3 knockdown notably inhibited cell proliferation and migration in OSCC. RNA immunoprecipitation, RNA pull down, and messenger RNA (mRNA) stability test verified that SNHG3 decoyed ELAV like RNA-binding protein 1 (ELAVL1) and therefore stabilized nuclear transcription factor Y subunit gamma (NFYC) mRNA to upregulate the expression levels of NFYC in OSCC cells. At last, it was confirmed by rescue experiments that the inhibiting impacts of SNHG3 knockdown on OSCC cell proliferation and migration could be partly revived by NFYC overexpression. Besides, we validated that Wnt/β-catenin pathway was also involved in SNHG3-regulated OSCC progression. In conclusion, SNHG3 might serve as a novel biomarker for OSCC.

MicroRNA-139-3p Inhibits The Growth And Metastasis Of Ovarian Cancer By Inhibiting ELAVL1

Background

The aberrant expression of microRNA-139-3p (miR-139-3p) has been recently involved in the development of multiple tumor types, but its function in ovarian cancer remains not well investigated. In this study, we mainly investigated the function of miR-139-3p in the progression of ovarian cancer.

Methods

The levels of miR-139-3p in ovarian cancer cells and tissues were detected using quantitative real-time-PCR (qRT-PCR) assay. The proliferation, colony formation, migration and invasion of ovarian cancer cell were determined, respectively. A luciferase reporter assay was used to confirm ELAV Like RNA Binding Protein 1 (ELAVL1) was a target gene of miR-139-3p. The expression of ELAVL1 was detected using Western blotting and immunofluorescence staining assay. The roles of miR-139-3p on the growth and metastasis of ovarian cancer cell in vivo were explored using transplanted tumor model and experimental lung metastasis model.

Results

MiR-139-3p was down-regulated in ovarian cancer tissues and ovarian cancer cell lines (SK-OV-3, A2780 and OVCAR-3). Overexpression of miR-139-3p decreased the growth, colony formation, migration and invasiveness of SK-OV-3 and OVCAR-3 cells. Moreover, overexpression of miR-139-3p reduced the growth and lung metastasis of ovarian cancer cells in vivo. The luciferase reporter gene assay indicated that ELAVL1 was a target of miR-139-3p and its expression was negatively regulated by miR-139-3p. Furthermore, the expression of ELAVL1 was inversely correlated with miR-139-3p level in ovarian cancer tissue.

Conclusion

Taken together, we demonstrated that miR-139-3p regulated ovarian cancer growth and metastasis by modulating the expression of ELAVL1.

Activation of ferritinophagy is required for the RNA-binding protein ELAVL1/HuR to regulate ferroptosis in hepatic stellate cells

Ferroptosis is a recently recognized form of regulated cell death that is characterized by lipid peroxidation. However, the molecular mechanisms regulating ferroptosis are largely unknown. In this study, we report that the RNA-binding protein ELAVL1/HuR plays a crucial role in regulating ferroptosis in liver fibrosis. Upon exposure to ferroptosis-inducing compounds, ELAVL1 protein expression was remarkably increased through the inhibition of the ubiquitin-proteasome pathway. ELAVL1 siRNA led to ferroptosis resistance, whereas ELAVL1 plasmid contributed to classical ferroptotic events. Interestingly, upregulated ELAVL1 expression also appeared to increase autophagosome generation and macroautophagic/autophagic flux, which was the underlying mechanism for ELAVL1-enhanced ferroptosis. Autophagy depletion completely impaired ELAVL1-mediated ferroptotic events, whereas autophagy induction showed a synergistic effect with ELAVL1. Importantly, ELAVL1 promoted autophagy activation via binding to the AU-rich elements within the F3 of the 3'-untranslated region of BECN1/Beclin1 mRNA. The internal deletion of the F3 region abrogated the ELAVL1-mediated BECN1 mRNA stability, and, in turn, prevented ELAVL1-enhanced ferroptosis. In mice, treatment with sorafenib alleviated murine liver fibrosis by inducing hepatic stellate cell (HSC) ferroptosis. HSC-specific knockdown of ELAVL1 impaired sorafenib-induced HSC ferroptosis in murine liver fibrosis. Noteworthy, we retrospectively analyzed the effect of sorafenib on HSC ferroptosis in advanced fibrotic patients with hepatocellular carcinoma receiving sorafenib monotherapy. Attractively, ELAVL1 upregulation, ferritinophagy activation, and ferroptosis induction occurred in primary human HSCs from the collected human liver tissue. Overall, these results reveal novel molecular mechanisms and signaling pathways of ferroptosis, and also identify ELAVL1-autophagy-dependent ferroptosis as a potential target for the treatment of liver fibrosis. Abbreviations: ACTA2/alpha-SMA: actin, alpha 2, smooth muscle, aorta; ACTB/beta-actin: actin beta; ARE: AU-rich element; ATG: autophagy related; BDL: bile duct ligation; BECN1: beclin 1; BSO: buthionine sulfoximine; COL1A1: collagen type I alpha 1 chain; ELAVL1/HuR: ELAV like RNA binding protein 1; FDA: fluorescein diacetate; FTH1: ferritin heavy chain 1; GOT1/AST: glutamic-oxaloacetic transaminase 1; GPT/ALT: glutamic-pyruvic transaminase; GPX4: glutathione peroxidase 4; GSH: glutathione; HCC: hepatocellular carcinoma; HSC: hepatic stellate cell; LCM: laser capture microdissection; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MDA: malondialdehydep; NCOA4: nuclear receptor coactivator 4; PTGS2: prostaglandin-endoperoxide synthase 2; ROS: reactive oxygen species; SQSTM1/p62: sequestosome 1; TBIL: total bilirubin; TEM: transmission electron microscopy; TGFB1: trasforming growth factor beta 1; UTR: untranslated region; VA-Lip-ELAVL1-siRNA: vitamin A-coupled liposomes carrying ELAVL1-siRNA.