Identification of miR-515-3p and its targets, vimentin and MMP3, as a key regulatory mechanism in esophageal cancer metastasis: functional and clinical significance

CD24 promotes metastasis and chemoresistance by directly targeting Arf6-ERK pathway in esophageal squamous cell carcinoma

Increasing evidence suggests the importance of CD24 in tumor progression, but its role and mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. The present study aims to explore the potential of CD24 as a novel predictive biomarker in ESCC, as well as its mechanism and therapeutic implications in metastasis and 5-FU chemoresistance. By using tissue microarray and immunohistochemistry, we found that CD24 expression was higher in ESCC tumor tissues than paired non-tumor tissues, further indicating that CD24 was markedly associated with poor prognosis. CD24 significantly promoted metastasis and 5-FU chemoresistance in vitro and in vivo. Mechanistically, CD24 competes with GIT2 to bind to Arf6, and stabilizes Arf6-GTP to activate the subsequent ERK pathway, thus promoting cancer progression. In addition, a significant positive correlation between CD24 and p-ERK was observed in clinical ESCC tissues. In summary, this study not only reveals CD24 as a regulatory factor for Arf6 activity, but also uncovers CD24-Arf6-ERK signaling axis as a novel mechanism of ESCC progression. Our findings suggest CD24 as a promising biomarker and therapeutic target in ESCC.

LINC00982-encoded protein PRDM16-DT regulates CHEK2 splicing to suppress colorectal cancer metastasis and chemoresistance

Metastasis is one of the key factors of treatment failure in late-stage colorectal cancer (CRC). Metastatic CRC frequently develops resistance to chemotherapeutic agents. This study aimed to identify the novel regulators from "hidden" proteins encoded by long noncoding RNAs (lncRNAs) involved in tumor metastasis and chemoresistance. Methods: CRISPR/Cas9 library functional screening was employed to identify the critical suppressor of cancer metastasis in highly invasive CRC models. Western blotting, immunofluorescence staining, invasion, migration, wound healing, WST-1, colony formation, gain- and loss-of-function experiments, in vivo experimental metastasis models, multiplex immunohistochemical staining, immunohistochemistry, qRT-PCR, and RT-PCR were used to assess the functional and clinical significance of FOXP3, PRDM16-DT, HNRNPA2B1, and L-CHEK2. RNA-sequencing, co-immunoprecipitation, qRT-PCR, RT-PCR, RNA affinity purification, RNA immunoprecipitation, MeRIP-quantitative PCR, fluorescence in situ hybridization, chromatin immunoprecipitation and luciferase reporter assay were performed to gain mechanistic insights into the role of PRDM16-DT in cancer metastasis and chemoresistance. An oxaliplatin-resistant CRC cell line was established by in vivo selection. WST-1, colony formation, invasion, migration, Biacore technology, gain- and loss-of-function experiments and an in vivo experimental metastasis model were used to determine the function and mechanism of cimicifugoside H-1 in CRC. Results: The novel protein PRDM16-DT, encoded by LINC00982, was identified as a cancer metastasis and chemoresistance suppressor. The down-regulated level of PRDM16-DT was positively associated with malignant phenotypes and poor prognosis of CRC patients. Transcriptionally regulated by FOXP3, PRDM16-DT directly interacted with HNRNPA2B1 and competitively decreased HNRNPA2B1 binding to exon 9 of CHEK2, resulting in the formation of long CHEK2 (L-CHEK2), subsequently promoting E-cadherin secretion. PRDM16-DT-induced E-cadherin secretion inhibited fibroblast activation, which in turn suppressed CRC metastasis by decreasing MMP9 secretion. Cimicifugoside H-1, a natural compound, can bind to LEU89, HIS91, and LEU92 of FOXP3 and significantly upregulated PRDM16-DT expression to repress CRC metastasis and reverse oxaliplatin resistance. Conclusions: lncRNA LINC00982 can express a new protein PRDM16-DT to function as a novel regulator in cancer metastasis and drug resistance of CRC. Cimicifugoside H-1 can act on the upstream of the PRDM16-DT signaling pathway to alleviate cancer chemoresistance.

MicroRNAs: A novel signature in the metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor, characterized by squamous cell differentiation, it is the sixth leading cause of cancer-related deaths globally. The increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered, coupled with higher risk of metastasis, which is an exceedingly malignant characteristic of cancer, frequently leading to a high mortality rate. Unfortunately, there is currently no specific and effective marker to predict and treat metastasis in ESCC. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules, approximately 22 nucleotides in length. miRNAs are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence, progression, and prognosis of cancer. Here, we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis, and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic factors. This review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis, with the ultimate aim of reducing the mortality rate among patients with ESCC.

KCTD4 interacts with CLIC1 to disrupt calcium homeostasis and promote metastasis in esophageal cancer

Increasing evidences suggest the important role of calcium homeostasis in hallmarks of cancer, but its function and regulatory network in metastasis remain unclear. A comprehensive investigation of key regulators in cancer metastasis is urgently needed. Transcriptome sequencing (RNA-seq) of primary esophageal squamous cell carcinoma (ESCC) and matched metastatic tissues and a series of gain/loss-of-function experiments identified potassium channel tetramerization domain containing 4 (KCTD4) as a driver of cancer metastasis. KCTD4 expression was found upregulated in metastatic ESCC. High KCTD4 expression is associated with poor prognosis in patients with ESCC and contributes to cancer metastasis in vitro and in vivo. Mechanistically, KCTD4 binds to CLIC1 and disrupts its dimerization, thus increasing intracellular Ca2+ level to enhance NFATc1-dependent fibronectin transcription. KCTD4-induced fibronectin secretion activates fibroblasts in a paracrine manner, which in turn promotes cancer cell invasion via MMP24 signaling as positive feedback. Furthermore, a lead compound K279-0738 significantly suppresses cancer metastasis by targeting the KCTD4‒CLIC1 interaction, providing a potential therapeutic strategy. Taken together, our study not only uncovers KCTD4 as a regulator of calcium homeostasis, but also reveals KCTD4/CLIC1-Ca2+-NFATc1-fibronectin signaling as a novel mechanism of cancer metastasis. These findings validate KCTD4 as a potential prognostic biomarker and therapeutic target for ESCC.

Targeting ARF1-IQGAP1 interaction to suppress colorectal cancer metastasis and vemurafenib resistance

INTRODUCTION

Acquired resistance to BRAF inhibitor vemurafenib is frequently observed in metastatic colorectal cancer (CRC), and it is a thorny issue that results in treatment failure. As adaptive responses for vemurafenib treatment, a series of cellular bypasses are response for the adaptive feedback reactivation of ERK signaling, which warrant further investigation.

OBJECTIVES

We identified ARF1 (ADP-ribosylation factor 1) as a novel regulator of both vemurafenib resistance and cancer metastasis, its molecular mechanism and potential inhibitor were investigated in this study.

METHODS

DIA-based quantitative proteomics and RNA-seq were performed to systematic analyze the profiling of vemurafenib-resistant RKO cells (RKO-VR) and highly invasive RKO cells (RKO-I8), respectively. Co‑immunoprecipitation assay was performed to detect the interaction of ARF1 and IQGAP1 (IQ-domain GTPase activating protein 1). An ELISA-based drug screen system on FDA-approved drug library was established to screen the compounds against the interaction of ARF1-IQGAP1.The biological functions of ARF1 and LY2835219 were determined by transwell, western blotting, Annexin V-FITC/PI staining and in vivo experimental metastasis assays.

RESULTS

We found that ARF1 strongly interacted with IQGAP1 to activate ERK signaling in VR and I8 CRC cells. Deletion of IQGAP1 or inactivation of ARF1 (ARF-T48S) restored the invasive ability induced by ARF1. As ARF1-IQGAP1 interaction is essential for ERK activation, we screened LY2835219 as novel inhibitor of ARF1-IQGAP1 interaction, which inactivated ERK signaling and suppressed CRC metastasis and vemurafenib-resistance in vitro and in vivo with no observed side effect. Furthermore, LY2835219 in combined treatment with vemurafenib exerted significantly inhibitory effect on ARF1-mediated cancer metastasis than used independently.

CONCLUSION

This study uncovers that ARF1-IQGAP1 interaction-mediated ERK signaling reactivation is critical for vemurafenib resistance and cancer metastasis, and that LY2835219 is a promising therapeutic agent for CRC both as a single agent and in combination with vemurafenib.

Lysine 2-hydroxyisobutyrylation of NAT10 promotes cancer metastasis in an ac4C-dependent manner

Posttranslational modifications add tremendous complexity to proteomes; however, gaps remain in knowledge regarding the function and regulatory mechanism of newly discovered lysine acylation modifications. Here, we compared a panel of non-histone lysine acylation patterns in metastasis models and clinical samples, and focused on 2-hydroxyisobutyrylation (Khib) due to its significant upregulation in cancer metastases. By the integration of systemic Khib proteome profiling in 20 paired primary esophageal tumor and metastatic tumor tissues with CRISPR/Cas9 functional screening, we identified N-acetyltransferase 10 (NAT10) as a substrate for Khib modification. We further showed that Khib modification at lysine 823 in NAT10 functionally contribute to metastasis. Mechanistically, NAT10 Khib modification enhances its interaction with deubiquitinase USP39, resulting in increased NAT10 protein stability. NAT10 in turn promotes metastasis by increasing NOTCH3 mRNA stability in an N4-acetylcytidine-dependent manner. Furthermore, we discovered a lead compound #7586-3507 that inhibited NAT10 Khib modification and showed efficacy in tumor models in vivo at a low concentration. Together, our findings bridge newly identified lysine acylation modifications with RNA modifications, thus providing novel insights into epigenetic regulation in human cancer. We propose that pharmacological inhibition of NAT10 K823 Khib modification constitutes a potential anti-metastasis strategy.

FRMD3 inhibits the growth and metastasis of breast cancer through the ubiquitination-mediated degradation of vimentin and subsequent impairment of focal adhesion

Recurrence and metastasis are the main causes of breast cancer (BRCA)-related death and remain a challenge for treatment. In-depth research on the molecular mechanisms underlying BRCA progression has been an important basis for developing precise biomarkers and therapy targets for early prediction and treatment of progressed BRCA. Herein, we identified FERM domain-containing protein 3 (FRMD3) as a novel potent BRCA tumor suppressor which is significantly downregulated in BRCA clinical tissue and cell lines, and low FRMD3 expression has been closely associated with progressive BRCA and shortened survival time in BRCA patients. Overexpression and knockdown experiments have revealed that FRMD3 significantly inhibits BRCA cell proliferation, migration, and invasion in vitro and suppresses BRCA xenograft growth and metastasis in vivo as well. Mechanistically, FRMD3 can interact with vimentin and ubiquitin protein ligase E3A(UBE3A) to induce the polyubiquitin-mediated proteasomal degradation of vimentin, which subsequently downregulates focal adhesion complex proteins and pro-cancerous signaling activation, thereby resulting in cytoskeletal rearrangement and defects in cell morphology and focal adhesion. Further evidence has confirmed that FRMD3-mediated vimentin degradation accounts for the anti-proliferation and anti-metastasis effects of FRMD3 on BRCA. Moreover, the N-terminal ubiquitin-like domain of FRMD3 has been identified as responsible for FRMD3-vimentin interaction through binding the head domain of vimentin and the truncated FRMD3 with the deletion of ubiquitin-like domain almost completely loses the anti-BRCA effects. Taken together, our study indicates significant potential for the use of FRMD3 as a novel prognosis biomarker and a therapeutic target of BRCA and provides an additional mechanism underlying the degradation of vimentin and BRCA progression.

Exosomal microRNAs: A Diagnostic and Therapeutic Small Bio-molecule in Esophageal Cancer

Esophageal cancer (EC) is one of the major causes of cancer-related death worldwide. EC is usually diagnosed at a late stage, and despite aggressive therapy, the five-year survival rate of patients remains poor. Exosomes play important roles in cancer biology. Indeed, exosomes are implicated in tumor proliferation, angiogenesis, and invasion. They contain bioactive molecules such as lipids, proteins, and non-coding RNAs. Exosome research has recently concentrated on microRNAs, which are tiny noncoding endogenous RNAs that can alter gene expression and are linked to nearly all physiological and pathological processes, including cancer. It is suggested that deregulation of miRNAs results in cancer progression and directly induces tumor initiation. In esophageal cancer, miRNA dysregulation plays an important role in cancer prognosis and patients' responsiveness to therapy, indicating that miRNAs are important in tumorigenesis. In this review, we summarize the impact of exosomal miRNAs on esophageal cancer pathogenesis and their potential applications for EC diagnosis and therapy.

Prognostic significance of sex determining region Y-box 2, E-cadherin, and vimentin in esophageal squamous cell carcinoma

BACKGROUND

Sex determining region Y-box 2 (SOX2) can promote squamous cell carcinoma (SSC) because it regulates the migration and invasion of several different types of squamous carcinoma cells. However, few studies have examined the prognostic value of SOX2 and its effect on the epithelial-mesenchymal transition (EMT) in esophageal SSC (ESCC), a cancer characterized by high invasion and rapid metastasis.

AIM

To verify the relationship of SOX2 and the EMT in ESCC and determine the prognostic value and significance of SOX2 and protein markers of the EMT in ESCC.

METHODS

One hundred and eighty-five postsurgical ESCC patients were retrospectively examined. Immunohistochemistry was used to detect SOX2, E-cadherin, and vimentin in ESCC tissues. The chi-square test was used to determine the relationships of the expression of these proteins with clinical data. Kaplan-Meier survival curves were used to evaluate factors associated with overall survival (OS).

RESULTS

SOX2 and vimentin had high expression in ESCC tissues and correlated with the depth of local carcinoma invasion. SOX2 expression had positive correlations with tumor size, vimentin expression, and the EMT, and a negative correlation with E-cadherin expression. Expression of SOX2 and vimentin had negative correlations with OS. SOX2 expression was an independent prognostic risk factor for poor OS in patients with ESCC.

CONCLUSION

SOX2 expression was an independent risk factor for OS in patients with ESCC and its expression had a positive correlation with the expression of vimentin, a classic marker of the EMT. SOX2 promoted the migration and invasion of ESCC, and this may related to its effect on vimentin in promoting the EMT.

Extracellular vesicles derived from patients with antibody-mediated rejection induce tubular senescence and endothelial to mesenchymal transition in renal cells

Extracellular vesicles (EV) are emerging mediators in several diseases. However, their role in the pathophysiology of antibody-mediated allograft rejection (AMR) has been poorly investigated. Here, we investigated the role of EV isolated from AMR patients in inducing tubular senescence and endothelial to mesenchymal transition (EndMT) and analyzed their miRNA expression profile. By multiplex bead flow cytometry, we characterized the immunophenotype of plasma AMR-derived EV and found a prevalent platelet and endothelial cell origin. In vitro, AMR-derived EV induced tubular senescence by upregulating SA-β Gal and CDKN1A mRNA. Furthermore, AMR-derived EV induced EndMT. The occurrence of tubular senescence and EndMT was confirmed by analysis of renal biopsies from the same AMR patients. Moreover, AMR-derived EV induced C3 gene upregulation and CFH downregulation in tubular epithelial cells, with C4d deposition on endothelial cells. Interestingly, RNase-mediated digestion of EV cargo completely abrogated tubular senescence and EndMT. By microarray analysis, miR-604, miR-515-3p, miR-let-7d-5p, and miR-590-3p were significantly upregulated in EV from AMR group compared with transplant controls, whereas miR-24-3p and miR-29a-3p were downregulated. Therefore, EV-associated miRNA could act as active player in AMR pathogenesis, unraveling potential mechanisms of accelerated graft senescence, complement activation and early fibrosis that might lead to new therapeutic intervention.

Identification of Potential miRNA-mRNA Regulatory Network in the Development of Oral Cancer

Background

Oral cancer is a difficult question in modern medical system, and there are few effective strategies to completely heal these diseases. This research investigated the miRNA-mRNA network in oral cancer development via bioinformatics excavation.

Methods

GSE28100 and GSE23558 in the GEO database were selected for bioinformatics analysis. The datasets were analyzed with GEO2R to obtain the related matrix files. The hot plot and heatmap of the matrix files were drawn with R language. The MiRDIP database was applied to predict and screen the targets of miRNAs. The DEGs in the matrix files were analyzed with the DAVID database and visualized with R language for enrichment analysis. The PPI-network of the DEGs was established with the STRING database and Cytoscape. Besides, the miRNA-mRNA was visualized by Cytoscape.

Results

35 genes were identified as the DEGs in GES28100. 1651 genes were identified as the DEGs in GSE23558. 143 common genes in the targets of miRNAs in GSE28100 and the DEGs in GSE the targets of DEGs in GES28100 and common genes were enriched in the PI3K/AKT pathway, MAPK pathway, etc. The DEGs in GSE28100 and GSE23558 were involved in the regulations of transcription from RNA polymerase II promoter and DNA transcription. The DEGs in GSE28100 and GSE23558 were established with the miRNA-mRNA network.

Conclusion

This research identified miR-15b-5p, miR-199a-3p, miR-21-5p, miR-424-5p, and miR-454-3p as the biomarker of oral cancer and established the miRNA-mRNA network in oral progression.

Anti-HIV drug elvitegravir suppresses cancer metastasis via increased proteasomal degradation of m6A methyltransferase METTL3

N6-methyladenosine (m6A) methylation is an abundant modification in eukaryotic mRNAs. Accumulating evidence suggests a role for RNA m6A methylation in various aspects of cancer biology. In this study, we aimed to explore the biological role of RNA m6A modification in tumor metastasis and to identify novel therapeutic strategies for esophageal squamous cell carcinoma (ESCC). Integration of genome-wide CRISPR/Cas9 functional screening with highly invasive and metastatic ESCC subline models led to the identification of METTL3, the catalytic subunit of the N6-adenosine-methyltransferase complex, as a promoter of cancer metastasis. METTL3 expression was upregulated in ESCC tumors and metastatic tissues. In vitro and in vivo experiments indicated that METTL3 increased m6A in EGR1 mRNA and enhanced its stability in a YTHDF3-dependent manner, activating EGR1/Snail signaling. Investigation into regulation of METTL3 expression found that KAT2A increased H3K27 acetylation levels in the METTL3 promoter region and activated transcription of METTL3 while SIRT2 exerted the opposite effects. Molecular docking and computational screening in a Food and Drug Administration (FDA)-approved compound library consisting of 1,443 small molecules identified compounds targeting METTL3 to suppress cancer metastasis. Elvitegravir, originally developed to treat human immunodeficiency virus (HIV) infection, suppressed metastasis by directly targeting METTL3 and enhancing its STUB1-mediated proteasomal degradation. Overall, RNA m6A modifications are important in cancer metastasis, and targeting METTL3 with elvitegravir has therapeutic potential for treating ESCC.

Targeting PFKL with penfluridol inhibits glycolysis and suppresses esophageal cancer tumorigenesis in an AMPK/FOXO3a/BIM-dependent manner

As one of the hallmarks of cancer, metabolic reprogramming leads to cancer progression, and targeting glycolytic enzymes could be useful strategies for cancer therapy. By screening a small molecule library consisting of 1320 FDA-approved drugs, we found that penfluridol, an antipsychotic drug used to treat schizophrenia, could inhibit glycolysis and induce apoptosis in esophageal squamous cell carcinoma (ESCC). Gene profiling and Ingenuity Pathway Analysis suggested the important role of AMPK in action mechanism of penfluridol. By using drug affinity responsive target stability (DARTS) technology and proteomics, we identified phosphofructokinase, liver type (PFKL), a key enzyme in glycolysis, as a direct target of penfluridol. Penfluridol could not exhibit its anticancer property in PFKL-deficient cancer cells, illustrating that PFKL is essential for the bioactivity of penfluridol. High PFKL expression is correlated with advanced stages and poor survival of ESCC patients, and silencing of PFKL significantly suppressed tumor growth. Mechanistically, direct binding of penfluridol and PFKL inhibits glucose consumption, lactate and ATP production, leads to nuclear translocation of FOXO3a and subsequent transcriptional activation of BIM in an AMPK-dependent manner. Taken together, PFKL is a potential prognostic biomarker and therapeutic target in ESCC, and penfluridol may be a new therapeutic option for management of this lethal disease.

Targeting of MAD2L1 by miR-515-5p involves the regulation of cell cycle arrest and apoptosis of colorectal cancer cells

Although many previous studies have found that the mitotic arrest deficient 2-like 1 (MAD2L1) protein contributes to the proliferation of colorectal cancer (CRC) cells, but the upstream mechanism of MAD2L1 is still largely elusive. This study aimed to explore the miRNAs upstream of MAD2L1 to improve our understanding of the mechanism of the MAD2L1 gene in CRC. The upstream target miRNAs (miR-515-5p) of MAD2L1 were predicted by the online databases miRWalk, miRDIP and TargetScan. Quantitative real-time PCR (qRT-PCR) was used to detect the expression level of miR-515-5p in human CRC tissues. The targeting relationship between miR-515-5p and MAD2L1 was tested by dual luciferase reporter gene assays. The effects of miR-515-5p on the biological behaviors of CRC cells by regulating MAD2L1 expression were verified by qRT-PCR, western blot, CCK-8, and flow cytometry. The results showed that miR-515-5p was a highly reliable upstream miRNA of the MAD2L1 gene. As an upstream target miRNA of MAD2L1, miR-515-5p was lowly expression in CRC tissues. The overexpression of miR-515-5p could inhibit the proliferation of CRC cells and induce cell cycle arrest at the G1 phase leading to cell apoptosis. However, MAD2L1 gene overexpression could reverse the effects of miR-515-5p overexpression on the biological behaviors of CRC cells above. This study illustrated that miR-515-5p can inhibit proliferation and induce G1 phase arrest leading to apoptosis in CRC cells. The mechanism underlying this phenomenon may be related to the negative targeted regulation of MAD2L1. This article is protected by copyright. All rights reserved.

Identification and validation of an autophagy-related gene signature for predicting prognosis in patients with esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal cancer. Since autophagy-related genes (ARGs) play a key role in the pathogenesis of many tumors, including ESCC, the purpose of this study is to establish an autophagy-related prognostic risk signature based on ARGs expression profile, and to provide a new method for improving prediction of clinical outcomes. We obtained the expression profiles of ESCC from public data (GSE53625) and extracted the portion of ARGs. Differential expression analysis and enrichment analysis were performed to confirm abnormal autophagy-related biological functions. Univariate and multivariate Cox regression analyses were performed on RNA microarray data (GSE53625) to construct a prognostic risk signature associated with autophagy. The performance of the model was evaluated by receiver operating characteristic (ROC) analysis, survival analysis and Brier score. The model was subjected to bootstrap internal validation. The potential molecular mechanism of gene signature was explored by gene set enrichment analysis (GSEA). Spearman correlation coefficient examined the correlation between risk score and immune status and ferroptosis. The expression levels of genes and proteins were validated by qRT-PCR and immunohistochemistry in ESCC cell lines and ESCC tissues. We constructed and validated an autophagy-related prognostic risk signature in 179 patients with ESCC. The long-term survival of patients in high-risk group was lower than that in low-risk group (log-rank, P value < 0.001). ROC analysis and Brier score confirmed the reliability of the signature. GSEA results showed significant enrichment of cancer- and autophagy-related signaling pathways in the high-risk ESCC patients and immunoregulatory signaling pathways in the low-risk ESCC patients. Correlation analysis showed that the risk signature can effectively predict the effect of immunotherapy. About 33.97% (71/209) ferroptosis-related genes were significantly correlated with risk scores. Finally, the results of qRT-PCR and immunohistochemistry experiments were consistent with bioinformatics analysis. In brief, we constructed a novel autophagy-related gene signature (VIM, UFM1, TSC2, SRC, MEFV, CTTN, CFTR and CDKN1A), which could improve the prediction of clinical outcomes in patients with ESCC.

New insights into the interplay between long non-coding RNAs and RNA-binding proteins in cancer

With the development of proteomics and epigenetics, a large number of RNA‐binding proteins (RBPs) have been discovered in recent years, and the interaction between long non‐coding RNAs (lncRNAs) and RBPs has also received increasing attention. It is extremely important to conduct in‐depth research on the lncRNA‐RBP interaction network, especially in the context of its role in the occurrence and development of cancer. Increasing evidence has demonstrated that lncRNA‐RBP interactions play a vital role in cancer progression; therefore, targeting these interactions could provide new insights for cancer drug discovery. In this review, we discussed how lncRNAs can interact with RBPs to regulate their localization, modification, stability, and activity and discussed the effects of RBPs on the stability, transport, transcription, and localization of lncRNAs. Moreover, we explored the regulation and influence of these interactions on lncRNAs, RBPs, and downstream pathways that are related to cancer development, such as N6‐methyladenosine (m6A) modification of lncRNAs. In addition, we discussed how the lncRNA‐RBP interaction network regulates cancer cell phenotypes, such as proliferation, apoptosis, metastasis, drug resistance, immunity, tumor environment, and metabolism. Furthermore, we summarized the therapeutic strategies that target the lncRNA‐RBP interaction network. Although these treatments are still in the experimental stage and various theories and processes are still being studied, we believe that these strategies may provide new ideas for cancer treatment.

Insights into Health-Promoting Effects of Plant MicroRNAs: A Review

Plant-derived microRNAs (miRNAs) play a significant role in human health and are "dark nutrients", as opposed to traditional plant nutrients, as well as important components of food diversification. Studies have revealed that multiple plant-derived miRNA pathways affect human health. First, plant miRNAs regulate plant growth and development and accumulation of metabolites, which alters the food quality and thus indirectly interferes with the health of the host. Moreover, when absorbed in vivo, some miRNAs may target the host cell mRNAs to affect protein expression. In addition, plant miRNAs target and reshape the human gut microbiota (GM), which interferes with the physiology and metabolism of the host. Therefore, miRNAs play a significant role in the cross-kingdom communication of plants, GM, and the host and in maintaining a balance of the three. Future contributions of plant miRNAs can bring new perspectives and opportunities to better understand food nutrition and health care research, which will facilitate the right exploitation of plant resources.

LncRNA miR205HG hinders HNRNPA0 translation: anti-oncogenic effects in esophageal carcinoma

Esophageal carcinoma (ESCA) affects 4 450 000 people and causes approximately 400 000 deaths annually worldwide, making it the sixth most lethal and eighth most common cancer. Patients with ESCA are often diagnosed at the later stages in which cancer cell metastasis is the main factor contributing to the low 5‐year survival rate (< 20%) of this disease. Long noncoding RNAs (lncRNAs) are a group of regulatory RNAs with a length of > 200 nucleotides but which fail to encode proteins. In this study, by using real‐time quantitative PCR, we found that the expression of the miR205 host gene (miR205HG; a lncRNA) was downregulated in ESCA tumors when compared with normal esophageal tissues or adjacent normal tissues of tumors. Furthermore, we demonstrated that miR205HG modulates the expression of extracellular matrix‐related genes in ESCA cells. In the transwell assay, downregulation of miR205HG contributes to migration and invasion of ESCA cells. In relation to the mechanism, our data show that miR205HG interacts with heterogeneous nuclear ribonucleoprotein A0 (HNRNPA0) mRNA and then hamper its translation by interacting with lin‐28 homolog A (LIN28A). Altogether, we highlight that the miR205HG‐HNRNPA0 axis is implicated in the migration and invasion of ESCA cells and that these members of this pathway may serve as therapeutic targets to inhibit metastasis of ESCA.

Vimentin Is at the Heart of Epithelial Mesenchymal Transition (EMT) Mediated Metastasis

Epithelial-mesenchymal transition (EMT) is a reversible plethora of molecular events where epithelial cells gain the phenotype of mesenchymal cells to invade the surrounding tissues. EMT is a physiological event during embryogenesis (type I) but also happens during fibrosis (type II) and cancer metastasis (type III). It is a multifaceted phenomenon governed by the activation of genes associated with cell migration, extracellular matrix degradation, DNA repair, and angiogenesis. The cancer cells employ EMT to acquire the ability to migrate, resist therapeutic agents and escape immunity. One of the key biomarkers of EMT is vimentin, a type III intermediate filament that is normally expressed in mesenchymal cells but is upregulated during cancer metastasis. This review highlights the pivotal role of vimentin in the key events during EMT and explains its role as a downstream as well as an upstream regulator in this highly complex process. This review also highlights the areas that require further research in exploring the role of vimentin in EMT. As a cytoskeletal protein, vimentin filaments support mechanical integrity of the migratory machinery, generation of directional force, focal adhesion modulation and extracellular attachment. As a viscoelastic scaffold, it gives stress-bearing ability and flexible support to the cell and its organelles. However, during EMT it modulates genes for EMT inducers such as Snail, Slug, Twist and ZEB1/2, as well as the key epigenetic factors. In addition, it suppresses cellular differentiation and upregulates their pluripotent potential by inducing genes associated with self-renewability, thus increasing the stemness of cancer stem cells, facilitating the tumour spread and making them more resistant to treatments. Several missense and frameshift mutations reported in vimentin in human cancers may also contribute towards the metastatic spread. Therefore, we propose that vimentin should be a therapeutic target using molecular technologies that will curb cancer growth and spread with reduced mortality and morbidity.

FoXA2 promotes esophageal squamous cell carcinoma progression by ZEB2 activation

Background

It has been reported that Forkhead transcription family member (FOXA2) regulates esophageal squamous cell carcinoma (ESCC) progression. However, the specific mechanism, by which FOXA2 promotes ESCC malignant progression, remains unclear.

Materials and methods

QRT-PCR and western blotting were applied to measure FOXA2 expression in ESCC tissues, while CCK-8 assay and Transwell assays were used to investigate the effect of FOXA2 on ESCC. Luciferase reporter assay, followed by fast chromatin immunoprecipitation (ChIP) assay, was used to study the relationship between FOXA2 and ZEB2.

Results

FOXA2 was significantly increased in ESCC tissues, when compared to normal tissues. Moreover, high expression of FOXA2 was also found in ESCC cells. Knockdown of FOXA2 inhibited ESCC cell proliferation, invasion, and migration. Mechanically, FOXA2 was verified to regulate ZEB2 expression at transcription level. Moreover, ZEB2 reversed the inhibitory effect of FOXA2 on ESCC proliferation, invasion, and migration. The relationship between ZEB2 and FOXA2 in ESCC tissues was negative.

Conclusions

These results indicate that FOXA2 plays a critical role in ESCC progression and may become a potential candidate target for ESCC treatment.

Roles of microRNAs in tumorigenesis and metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the major subtype of esophageal cancer that is prevalent in Eastern Asia. Despite recent advances in therapy, the outcome of ESCC patients is still dismal. MicroRNAs (miRNAs) are non-coding RNAs which can negatively modulate gene expression at the post-transcriptional level. The involvement and roles of miRNAs have become one of the hot topics of cancer research in recent years. In ESCC, genetic variations within miRNA coding genes were found to have distinct epidemiological significance in different populations. Dysregulated expression of several miRNAs was reported to be associated with therapeutic response. Functionally, miRNAs can act either in an oncogenic or a tumor-suppressive manner during tumorigenesis of ESCC by interrupting signaling pathways associated with cell proliferation, metabolism, cancer stemness, and resistance to chemo- or radiotherapy. Moreover, miRNAs modulate metastasis of ESCC by targeting genes that regulate cytoskeleton dynamics, extracellular matrix remodeling, epithelial-mesenchymal transition, and tumor microenvironment. Most importantly, mounting evidence suggests that inhibiting oncogenic miRNAs or restoring the loss of tumor-suppressive miRNAs has therapeutic potential in the treatment of ESCC. Here, we review and discuss recent studies on the significance, biological functions, and therapeutic potential of miRNAs in tumorigenesis and metastasis of ESCC.

Construction of a Prognostic Immune-Related LncRNA Risk Model for Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) originates mainly from the mucous epithelium and glandular epithelium of the bronchi. It is the most common pathologic subtype of non-small cell lung cancer (NSCLC). At present, there is still a lack of clear criteria to predict the efficacy of immunotherapy. The 5-year survival rate for LUAD patients remains low.

Methods

All data were downloaded from The Cancer Genome Atlas (TCGA) database. We used Gene Set Enrichment Analysis (GSEA) database to obtain immune-related mRNAs. Immune-related lncRNAs were acquired by using the correlation test of the immune-related genes with R version 3.6.3 (Pearson correlation coefficient cor = 0.5, P < 0.05). The TCGA-LUAD dataset was divided into the testing set and the training set randomly. Based on the training set to perform univariate and multivariate Cox regression analyses, we screened prognostic immune-related lncRNAs and given a risk score to each sample. Samples were divided into the high-risk group and the low-risk group according to the median risk score. By the combination of Kaplan–Meier (KM) survival curve, the receiver operating characteristic (ROC) (AUC) curve, the independent risk factor analysis, and the clinical data of the samples, we assessed the accuracy of the risk model. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on the differentially expressed mRNAs between the high-risk group and the low-risk group. The differentially expressed genes related to immune response between two risk groups were analyzed to evaluate the role of the model in predicting the efficacy and effects of immunotherapy. In order to explain the internal mechanism of the risk model in predicting the efficacy of immunotherapy, we analyzed the differentially expressed genes related to epithelial-mesenchymal transition (EMT) between two risk groups. We extracted RNA from normal bronchial epithelial cell and LUAD cells and verified the expression level of lncRNAs in the risk model by a quantitative real-time polymerase chain reaction (qRT-PCR) test. We compared our risk model with other published prognostic signatures with data from an independent cohort. We transfected LUAD cell with siRNA-LINC0253. Western blot analysis was performed to observed change of EMT-related marker in protein level.

Results

Through univariate Cox regression analysis, 24 immune-related lncRNAs were found to be strongly associated with the survival of the TCGA-LUAD dataset. Utilizing multivariate Cox regression analysis, 10 lncRNAs were selected to establish the risk model. The K-M survival curves and the ROC (AUC) curves proved that the risk model has a fine predictive effect. The GO enrichment analysis indicated that the effect of the differentially expressed genes between high-risk and low-risk groups is mainly involved in immune response and intercellular interaction. The KEGG enrichment analysis indicated that the differentially expressed genes between high-risk and low-risk groups are mainly involved in endocytosis and the MAPK signaling pathway. The expression of genes related to the efficacy of immunotherapy was significantly different between the two groups. A qRT-PCR test verified the expression level of lncRNAs in LUAD cells in the risk model. The AUC of ROC of 5 years in the independent validation dataset showed that this model had superior accuracy. Western blot analysis verified the change of EMT-related marker in protein level.

Conclusion

The immune lncRNA risk model established by us could better predict the prognosis of patients with LUAD.