Clinical role of the long non‑coding RNA, EGFR‑AS1, in patients with cancer: A systematic review and meta‑analysis

The novel long non-coding RNA, EGFR-AS1, is expressed in various types of solid tumour, and its oncogenic role has been fully identified. In the present study, several articles were screened following an electronic search of the PubMed database. In total, 8 studies were included in the present systematic review. For each analysis indicator risk ratios (RRs) with 95% confidence intervals (CIs) or hazard ratios (HRs) with standard errors and 95% CIs were estimated using Review Manager 5.3. The pooled RR of high EGFR-AS1 expression among patients with or without vascular invasion was 1.81 with a 95% CI of 1.22-2.69; the pooled HR of high EGFR-AS1 expression for patient overall survival rate was 1.74 with a 95% CI of 1.39-2.18. Therefore, EGFR-AS1 was identified as an oncogene and the upregulated EGFR-AS1 expression was significantly associated with advanced tumour progression and poor prognosis.

Super enhancer loci of EGFR regulate EGFR variant 8 through enhancer RNA and strongly associate with survival in HNSCCs

Epidermal growth factor receptor (EGFR) has been shown to be overexpressed in human cancers due to mutation, amplification, and epigenetic hyperactivity, which leads to deregulated transcriptional mechanism. Among the eight different EGFR isoforms, the mechanism of regulation of full-length variant 1 is well-known, no studies have examined the function & factors regulating the expression of variant 8. This study aimed to understand the function of EGFR super-enhancer loci and its associated transcription factors regulating the expression of EGFR variant 8. Our study shows that overexpression of variant 8 and its transcription was more prevalent than variant 1 in many cancers and positively correlated with the EGFR-AS1 expression in oral cancer and HNSCC. Notably, individuals overexpressing variant 8 showed shorter overall survival and had a greater connection with other clinical traits than patients with overexpression of variant 1. In this study, TCGA enhancer RNA profiling on the constituent enhancer (CE1 and CE2) region revealed that the multiple enhancer RNAs formed from CE2 by employing CE1 as a promoter. Our bioinformatic analysis further supports the enrichment of enhancer RNA specific chromatin marks H3K27ac, H3K4me1, POL2 and H2AZ on CE2. GeneHancer and 3D chromatin capture analysis showed clustered interactions between CE1, CE2 loci and this interaction may regulates expression of both EGFR-eRNA and variant 8. Moreover, increased expression of SNAI2 and its close relationship to EGFR-AS1 and variant 8 suggest that SNAI2 could regulates variant 8 overexpression by building a MegaTrans complex with both EGFR-eRNA and EGFR-AS1. Our findings show that EGFR variant 8 and its transcriptional regulation & chromatin modification by eRNAs may provide a rationale for targeting RNA splicing in combination with targeted EGFR therapies in cancer.

A promising new cancer marker: Long noncoding RNA EGFR-AS1

Cancer consists of a group of diseases with the salient properties of an uncontrolled cell cycle, metastasis, and evasion of the immune response, mainly driven by the genomic instability of somatic cells and the physicochemical environment. Long noncoding RNAs (lncRNAs) are defined as noncoding RNAs with a length of more than 200 nucleotides. LncRNA dysregulation participates in diverse disease types and is tightly associated with patient clinical features, such as age, disease stage, and prognosis. In addition, an increasing number of lncRNAs have been confirmed to regulate a series of biological and pathological processes through numerous mechanisms. The lncRNA epidermal growth factor receptor antisense RNA 1 (EGFR-AS1) was recently discovered to be aberrantly expressed in many types of diseases, particularly in cancers. A high level of EGFR-AS1 was demonstrated to correlate with multiple patient clinical characteristics. More importantly, EGFR-AS1 was found to be involved in the mediation of various cellular activities, including cell proliferation, invasion, migration, chemosensitivity, and stemness. Therefore, EGFR-AS1 is a promising marker for cancer management. In this review, we introduce the expression profile, molecular mechanisms, biological functions, and clinical value of EGFR-AS1 in cancers.

H3K27ac-activated EGFR-AS1 promotes cell growth in cervical cancer through ACTN4-mediated WNT pathway

Background

Recently, extensive studies unveiled that lncRNAs exert critical function in the development and progression of cervical cancer (CC). EGFR-AS1 is a novel lncRNA which has not been well-explored in CC.

Aims

Our study aimed to research the function and molecular mechanism of EGFR-AS1 in CC cells. qRT-PCR analysis was performed to detect gene expression. Colony formation, EdU, flow cytometry, TUNEL, western blot and transwell assays were performed to assess the effect of EGFR-AS1 on CC cell growth. The regulatory mechanism of EGFR-AS1 was dug out through mechanism experiments.

Results

EGFR-AS1 was notably overexpressed in CC cell lines. Loss-of-functional experiments revealed that EGFR-AS1 promoted CC cell proliferation, migration and invasion, and suppressed cell apoptosis. Mechanistically, up-regulation of EGFR-AS1 was attributed to the activation of H3K27 acetylation (H3K27ac). Further, EGFR-AS1 was revealed to function as miR-2355-5p sponge. Additionally, miR-2355-5p was down-regulated in CC cells and ACTN4 was identified as a target gene of miR-2355-5p. Ultimately, overexpressed ACTN4 could reserve the suppressive role of EGFR-AS1 silencing in CC cell growth. Last but not least, EGFR-AS1 facilitated CC cell growth via ACTN4-mediated WNT pathway.

Conclusions

H3K27ac-activated EGFR-AS1 sponged miR-2355-5p and promoted CC cell growth through ACTN4-mediated WNT pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13062-021-00315-5.

LncRNA EGFR-AS1 Upregulates ROCK1 by Sponging miR-145 to Promote Esophageal Squamous Cell Carcinoma Cell Invasion and Migration

Background: EGFR-AS1 has been characterized as an oncogenic lncRNA in many types of cancers, while its roles in esophageal squamous cell carcinoma (ESCC) are unknown. Results: Their data showed that EGFR-AS1 and ROCK1 were upregulated in ESCC and positively correlated. Survival analysis showed that high EGFR-AS1 and ROCK1 expression levels predicted poor survival. In ESCC cells, EGFR-AS1 overexpression led to upregulated ROCK1, while miR-145 overexpression led to downregulated ROCK1 and reduced effects of EGFR-AS1 overexpression. Bioinformatics analysis showed that miR-145 may bind EGFR-AS1, while overexpression of EGFR-AS1 and miR-145 did not significantly affect each other. In esophageal squamous cell carcinoma (ESCC) cells, EGFR-AS1 and ROCK1 overexpression mediated the increased rates of ECSS cell invasion and migration. Overexpression of miR-145 played an opposite role and attenuated the effects of EGFR-AS1 overexpression. Conclusion: Therefore, EGFR-AS1 may upregulate ROCK1 by sponging miR-145 to promote ESCC cell invasion and migration.

The lncRNA EGFR-AS1 is linked to migration, invasion and apoptosis in glioma cells by targeting miR-133b/RACK1

Glioblastoma multiforme (GBM) is the most common in situ neoplasms in central nervous system (CNS). However, the pathogenesis of GBM is poorly understood. Long noncoding RNAs (lncRNAs) have been implicated in GBM progression. In this study, we attempted to identify the biological role of the EGFR-AS1 in glioma cells and tissues, as well as reveal the molecular mechanism associated. The results indicated that lnc-EGFR-AS1 expression was increased in glioma cells and tissues. EGFR-AS1 knockdown suppressed proliferation, migration and invasion of glioma cells, but induced apoptosis. Additionally, lnc-EGFR-AS1 functioned as a sponge for miR-133b. Promoting lnc-EGFR-AS1 expression significantly reduced miR-133b expression. Furthermore, miR-133b could target the 3'-untranslated region (3'-UTR) of RACK1 and reduced its expression levels. What's more, lnc-EGFR-AS1 knockdown reduced RACK1 expression partly through enhancing miR-133b expression. In vivo experiments confirmed the anti-tumorigenesis capability of EGFR-AS1 knockdown. These findings elucidated that EGFR-AS1 accelerated cell proliferation, migration, invasion and prevented apoptosis in glioma cells by regulating miR-133b/RACK1, providing new insights for the diagnosis and molecular therapy of GBM.

Long Noncoding RNA EGFR-AS1 Promotes Cell Proliferation by Increasing EGFR mRNA Stability in Gastric Cancer

BACKGROUND/AIMS

LncRNA EGFR-AS1 is an antisense transcript of EGFR, which plays a key role in gastric cancer progression. This study was aimed to explore the effects of lncRNA EGFR-AS1 on GC and the underling mechanisms.

METHODS

The silencing of EGFR-AS1 expression was performed by using EGFR-AS1 shRNA lentivirus in MGC803 and SGC-7901 GC cell. The levels of lncRNA EGFR-AS1 and EGFR were detected by qPCR and western blot. Cell proliferation was assessed by CCK-8, EdU, and colony formation assays. The EGFR mRNA stability was explored by using RNA synthesis inhibitor α-amanitin.

RESULTS

In our study, EGFR-AS1 significantly up-regulated in GC tissues and correlated with tumor size. And the expression of EGFR-AS1 positively correlated with EGFR in tissues. Moreover, knock-down of EGFR-AS1 inhibited the proliferation of GC cells via suppressing EGFR-dependent PI3K/AKT pathway in vitro and in vivo. Mechanismly, depletion of EGFR-AS1 was found to decrease EGFR expression by reduction of EGFR mRNA stability.

CONCLUSION

Our findings suggested that EGFR-AS1 might have an oncogenic effect on GC and serve as a potential target of GC.

The long noncoding RNA, EGFR-AS1, a target of GHR, increases the expression of EGFR in hepatocellular carcinoma

LncRNA has provided an important new perspective regarding gene regulation. Both the expression and activation of EGFR have been proven to be under the tight control of the GHR pathway. EGFR-AS1 has been found to inhibit the expression of EGFR. GHR-siRNA and EGFR-AS1-siRNA were transfected into HCC cell lines, and a series of WB, q-PCR, and IF experiments was conducted to evaluate whether EGFR-AS1 participated in the regulation of GHR and EGFR. We found that impeded expression of GHR decreased the expression of EGFR and EGFR-AS1 in vivo and in vitro. Then, it was verified that EGFR and EGFR-AS1 were relatively upregulated in HCC tissue, and they were significantly related to some clinical characteristics and patient prognosis. Furthermore, EGFR-AS1 was determined to promote HCC development by improving the ability of invasion and proliferation of HCC cells in vitro, and it was also found to affect the cell cycle. Our study identified that EGFR-AS1 may promote HCC genesis and development. EGFR-AS1 may act as a prognostic factor in HCC. More importantly, we observed that the inhibition of EGFR-AS1 in HCC cells significantly impeded cell proliferation and invasion in vivo, which might provide a potential possibility for targeted therapy of HCC.