LINC01939 inhibits the metastasis of gastric cancer by acting as a molecular sponge of miR-17-5p to regulate EGR2 expression

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

Lnc90386 Sponges miR-33-5p to Mediate Mycoplasma gallisepticum-Induced Inflammation and Apoptosis in Chickens via the JNK Pathway

Mycoplasma gallisepticum (MG) is one of the most important pathogens, that causes chronic respiratory disease (CRD) in chickens. Long non-coding RNAs (lncRNAs) are emerging as new regulators for many diseases and some lncRNAs can function as competing endogenous RNAs (ceRNAs) to regulate mRNAs by competitively binding to miRNAs. Here, we found that miR-33-5p was significantly up-regulated both in MG-infected chicken embryonic lungs and chicken embryo fibroblast cells (DF-1), and Lnc90386 negatively correlated with miR-33-5p. miR-33-5p, as a new regulator for MG infection, repressed apoptosis, inflammatory factors in DF-1 cells by targeting JNK1. Further analyses showed that Lnc90386 sponged miR-33-5p to weaken its inhibitory effect on JNK1, forming the ceRNA regulatory network. Furthermore, knockdown of Lnc90386 significantly inhibited apoptosis and inflammatory factors, and promoted DF-1 cells proliferation. However, co-treatment with miR-33-5p inhibitor and Lnc90386 siRNA showed that knockdown of Lnc90386 could partially eliminate the inhibiting effect of miR-33-5p inhibitor on inflammation, cell apoptosis and proliferation. In conclusion, Lnc90386 sponges miR-33-5p to defend against MG infection by inhibiting the JNK signaling pathway.

Regulatory mechanisms and potential medical applications of HNF1A-AS1 in cancers

Long noncoding RNAs (lncRNAs) are defined as a class of non-protein-coding RNAs that are longer than 200 nucleotides. Previous studies have shown that lncRNAs play a vital role in the progression of multiple diseases, which highlights their potential for medical applications. The lncRNA hepatocyte nuclear factor 1 homeobox A (HNF1A) antisense RNA 1 (HNF1A-AS1) is known to be abnormally expressed in multiple cancers. HNF1A-AS1 exerts its oncogenic roles through a variety of molecular mechanisms. Moreover, aberrant HNF1A-AS1 expression is associated with diverse clinical features in cancer patients. Therefore, HNF1A-AS1 is a promising biomarker for tumor diagnosis and prognosis and thus a potential candidate for tumor therapy. This review summarizes current studies on the role and the underlying mechanisms of HNF1A-AS1 various cancer types, including gastric cancer, liver cancer, glioma, lung cancer, colorectal cancer, breast cancer, bladder cancer, osteosarcoma, esophageal adenocarcinoma, hemangioma, oral squamous cell carcinoma, laryngeal squamous cell carcinoma, cervical cancer, as well as gastroenteropancreatic neuroendocrine neoplasms. We also describe the diagnostic, prognostic, and therapeutic value of HNF1A-AS1 for multiple cancer patients.

Leonurus japonicus Houttuyn induces reactive oxygen species-mediated apoptosis via regulation of miR-19a-3p/PTEN/PI3K/AKT in U937 and THP-1 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus japonicus Houttuyn is a medicinal ingredient in more than 300 prescriptions in traditional Korean medicine. It is especially important for women's health and blood-related diseases. Recent research revealed that Leonurus japonicus Houttuyn extracts have antioxidative, anticancer, analgesic, anti-inflammatory, and neuroprotective properties.

AIM OF THE STUDY

However, its underlying anti-cancerous mechanisms remain unclear. This study elucidated the anticancer mechanism of Leonurus japonicus Houttuyn in U937 and THP-1 cancer cells.

MATERIALS AND METHODS

High-performance liquid chromatography (HPLC) was used for detecting main compound of Leonurus japonicus Houttuyn, rutin. EZ-Cytox cell viability assay, Western blot analysis, live and dead cell assay, 2', 7' dichlorofluorescin diacetate (DCFDA) assay, quantitative real-time PCR (qRT-PCR) analysis, and microRNA (miR) mimic transfection assay were applied to further investigate anti-cancer efficacies and underlying mechanism in U937 and THP-1 cells.

RESULTS

The main compound of Leonurus japonicus Houttuyn, rutin was detected using HPLC. The cytotoxic effect of Leonurus japonicus Houttuyn was exerted in U937 and THP-1 cancer cells but not in MDBK and IEC-6 normal cells. Leonurus japonicus Houttuyn decreased mitochondria membrane potential (ΔΨm). Consistently, Leonurus japonicus Houttuyn reduced the expression of survivin and cleaved caspase-9, caspase-3, and poly (ADP-ribose) polymerase (PARP). Cell death was increased in Leonurus japonicus Houttuyn treated groups. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and CCAAT-enhancer-binding protein homologous protein (CHOP) was increased and phosphatidylinositol-3-kinase (PI3K) and Protein kinase B (AKT) were decreased by Leonurus japonicus Houttuyn. Reactive oxygen speices generation was elevated by Leonurus japonicus Houttuyn and its cytotoxicity was reversed by N-acetyl-l-cysteine (NAC) pretreatment. Moreover, onco-microRNA (miR), miR-19a-3p was suppressed by Leonurus japonicus Houttuyn and transfection of miR-19a-3p mimic reversed the regulated PTEN, p-AKT, CHOP expression, attenuating Leonurus japonicus Houttuyn induced apoptosis.

CONCLUSIONS

These findings indicated that Leonurus japonicus Houttuyn has anti-cancer effects by regulation of PTEN/PI3K/AKT signal pathway and ROS-related ER stress-induced apoptosis via regulation of miR-19a-3p. Leonurus japonicus Houttuyn may be an effective candidate for triggering PTEN-dependent apoptosis of cancer cells related to acute myeloid leukemia.

Long Noncoding RNA HAND2-AS1 Suppresses Cell Proliferation, Migration, and Invasion of Bladder Cancer via miR-17-5p/KLF9 Axis

Bladder cancer (BC) is the most common type of malignant tumor in the genitourinary system. Through the microarray analysis of clinical samples, long noncoding RNA HAND2-AS1 expression was found to be downregulated in BC tissues. However, the function of HAND2-AS1 on BC and underlying mechanism are unclear. In this study, the correlations of HAND2-AS1 with clinicopathological parameters in BC patients were determined. The gain- and loss-of-function experiments were conducted to examine the role of HAND2-AS1 in malignant behaviors of BC cells in vitro and in vivo. Then, we paid attention to miR-17-5p/KLF9 axis to illustrate the molecular mechanism. Results showed that HAND2-AS1 was downregulated in BC tissues, and its overexpression significantly inhibited cell proliferation, migration, and invasion in vitro, as well as tumor growth in vivo. Knockdown of HAND2-AS1 caused an opposite effect on BC cell malignancies. Furthermore, miR-17-5p was shown to be a direct target of HAND2-AS1, and it reversed the inhibitory effect of HAND2-AS1 on BC malignancies. Also, as a downstream factor of miR-17-5p, KLF9 silencing was demonstrated to mediate the role of miR-17-5p inhibitor in BC cell proliferation and invasion. Thus, it suggests that HAND2-AS1 acts as a suppressor in BC development through miR-17-5p/KLF9 axis.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

LINC01436 Inhibited miR-585-3p Expression and Upregulated MAPK1 Expression to Promote Gastric Cancer Progression

BACKGROUND

Gastric cancer (GC) is a prevalent type of digestion system malignancies. Dysregulation of long non-coding RNAs (lncRNAs) has been proven to be prognostic factors and biological regulators in human cancers.

AIMS

The current study aimed to explore the role of long intergenic non-protein coding RNA 1436 (LINC01436) and its underlying mechanism in the progression of GC.

METHODS

RT-qPCR was conducted to measure RNA expression. Western blot was used for exploration of protein level. CCK-8, caspase-3 activity, and transwell assays were applied to evaluate the proliferative, apoptotic, and migratory abilities of GC cells, respectively. Mechanical experiments were used to probe the molecular interplay between genes.

RESULTS

High LINC01436 level suggested low overall survival in GC patients, and LINC01436 was highly expressed in GC tissues and cells. Besides, LINC01436 knockdown hampered cell proliferation and migration, while facilitated cell apoptosis. Mechanistically, LINC01436 upregulated mitogen-activated protein kinase 1 (MAPK1) expression by competitively binding with miR-585-3p and inhibiting miR-585-3p expression. Furthermore, LINC01436 negatively regulated miR-585-3p expression by enhancing the zeste 2 polycomb repressive complex 2 subunit (EZH2)-induced trimethylation of histone H3 at lysine 27 (H3K27me3) on miR-585-3p promoter. Final rescue assays revealed that overexpression of MAPK1 could rescue the suppressive influence of LINC01436 depletion on GC progression.

CONCLUSIONS

LINC01436 epigenetically silences miR-585-3p and acts as miR-585-3p to upregulate MAPK1 expression and promote GC progression.

Explore prognostic biomarker of bladder cancer based on competing endogenous network

Bladder cancer (BC) is the most common tumor of the urinary tract. Increasing evidence showed that long non-coding RNA (lncRNA) is a critical regulator in cancer development and progression. However, the functions of lncRNAs in the development of BC remain mostly undefined. In the present study, based on RNA sequence profiles from The Cancer Genome Atlas database, we identified 723 lncRNAs, 157 miRNAs, and 1816 mRNAs aberrantly expressed in BC tissues. A competing endogenous RNA network, including 49 lncRNAs, 17 miRNAs, and 36 mRNAs, was then established. The functional enrichment analyses showed that the mRNAs in the ceRNA network mainly participated in ‘regulation of transcription’ and ‘pathways in cancer’. Moreover, the Cox regression analyses demonstrated that three lncRNAs (AC112721.1, TMPRSS11GP, and ADAMTS9-AS1) could serve as independent risk factors. We established a risk prediction model with these lncRNAs. Kaplan–Meier curve analysis showed that high-risk patients’ prognosis was lower than that of low-risk patients (P=0.001). The present study provides novel insights into the lncRNA-mediated ceRNA network and the potential of lncRNAs to be candidate prognostic biomarkers in BC, which could help better understand the pathological changes and pathogenesis of BC and be useful for clinical studies in the future.

NFAT2 overexpression suppresses the malignancy of hepatocellular carcinoma through inducing Egr2 expression

BACKGROUND

Nuclear factor of activated T cells 2 (NFAT2) has been reported to regulate the development and malignancy of few tumors. In this study, we aimed to explore the effect of NFAT2 expression on cell fate of HepG2 cell and its potential mechanisms.

METHODS

Firstly, the pcDNA3.1-NFAT2 plasmid was transfected into HepG2 cells to construct NFAT2 overexpressed HepG2 cells. Then, the chemical count kit-8 cell viability assay, Annexin V-FITC apoptosis detection, EdU labeling proliferation detection, transwell and wound healing experiments were performed. The expression of Egr2 and FasL, and the phosphorylation of AKT and ERK, after ionomycin and PMA co-stimulation, was detected, while the Ca2+ mobilization stimulated by K+ solution was determined. At last, the mRNA and protein expression of NFAT2, Egr2, FasL, COX-2 and c-myc in carcinoma and adjacent tissues was investigated.

RESULTS

The NFAT2 overexpression suppressed the cell viability, invasion and migration capabilities, and promoted apoptosis of HepG2 cells. NFAT2 overexpression induced the expression of Egr2 and FasL and suppressed the phosphorylation of AKT and ERK. The sensitivity and Ca2+ mobilization of HepG2 cells was also inhibited by NFAT2 overexpression. Compared with adjacent tissues, the carcinoma tissues expressed less NFAT2, Egr2, FasL and more COX-2 and c-myc.

CONCLUSION

The current study firstly suggested that NFAT2 suppressed the aggression and malignancy of HepG2 cells through inducing the expression of Egr2. The absence of NFAT2 and Egr2 in carcinoma tissues reminded us that NFAT2 may be a promising therapeutic target for hepatocellular carcinoma treatment.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

LncRNA SNHG17 aggravated prostate cancer progression through regulating its homolog SNORA71B via a positive feedback loop

Prostate cancer (PC) is a prevalent male malignancy with high occurrence rate. Recent studies have showed that small nucleolar host genes (SNHGs) and their homolog small nucleolar RNAs (snoRNAs) elicit regulatory functions in carcinogenesis. Present study aimed to investigate the role of SNHG17 and its homolog SNORA71B in PC. Function of SNHG17 and SNORA71B in PC is detected by CCK-8, colony formation, flow cytometry analysis of apoptosis, and transwell migration assay. The mechanism whereby SNHG17 regulated SNORA71B was detected by RIP, pulldown, ChIP, and luciferase reporter assays. Results depicted that transcript 6 of SNHG17 and SNORA71B were upregulated in PC. Knockdown of SNHG17 or SNORA71B weakened proliferation, invasion, migration, and epithelial-to-mesenchymal transition (EMT) and strengthened apoptosis. Mechanistically, SNHG17 and SNORA71B were transcriptionally activated by signal transducer and activator of transcription 5A (STAT5A). SNHG17 positively regulated SNORA71B in PC cell lines and other cell lines. SNHG17 sponged miR-339-5p to upregulate STAT5A and therefore to cause transactivation of SNORA71B. Rescue experiments delineated that SNORA71B was required for the regulation of SNHG17 on PC. Moreover, SNHG17 silence hindered tumorigenesis of PC in vivo. In conclusion, current study first revealed that lncRNA SNHG17 aggravated prostate cancer progression through regulating its homolog SNORA71B via a positive feedback loop, which might do help to the pursuit of better PC treatment.

MiR-17-5p promotes cellular proliferation and invasiveness by targeting RUNX3 in gastric cancer

BACKGROUND

Dysregulated microRNAs (miRNAs/miRs) directly modulate the biological functions of gastric cancer (GC) cells and contribute to the initiation and progression of GC. MiR-17-5p and runt-related transcription factor 3 (RUNX3) have been reported to be related to GC progression; however, the specific interaction between miR-17-5p and RUNX3 in GC require further investigation.

METHODS

Western blotting, real-time PCR and immunohistochemistry were used to study the expression level of miR-17-5p and RUNX3 in gastric cancer tissues and plasma. The biological function of miR-17-5p was examined by measuring cell proliferation, apoptosis and cell invasion in vitro; the target gene of miR17-5p was identified by luciferase reporter assays, RNA Binding protein immunoprecipitation (RIP) and western blotting. In vivo animal study was conducted to confirm the role of miR-17-5p during tumorigensis of gastric cancer.

RESULTS

This study showed that miR17-5p was upregulated in the plasma and tissues of patients with GC, while RUNX3 was downregulated in GC tissues. Functional experiments indicated that miR-17-5p mimics promoted the proliferation and invasion of GC via suppressing apoptosis in vitro. Furthermore, bioinformatics prediction, luciferase reporter assays, reverse transcription quantitative polymerase chain reaction assays, RIP and western blotting analysis demonstrated that RUNX3 was a direct target gene of miR-17-5p in GC. In addition, overexpression of RUNX3 suppressed the proliferation and invasiveness of GC cells. In vivo data indicated miR-17-5p agomir significantly promoted tumor growth. In contrast, miR-17-5p antagomir notably decreased tumor volume compared with control group.

CONCLUSIONS

MiR-17-5p promoted the progression of GC via directly targeting RUNX3, suggesting that miR-17-5p and RUNX3 could be considered as diagnostic and therapeutic targets for patients with GC.

Long noncoding RNA LINC00339 promotes the oncogenicity of gastric cancer by regulating SRY-box 9 expression via sponging of microRNA-539

Differential expression of LINC00339 is involved in the malignancy of multiple human cancer types. Nonetheless, the expression profile, functions, and potential mechanisms of action of LINC00339 in gastric cancer are yet to be fully elucidated. This study aimed at measuring LINC00339 expression in gastric cancer and examining the prognostic significance of LINC00339 in patients with gastric cancer. The detailed functions of LINC00339 with regard to the aggressive characteristics of gastric cancer cells and the underlying molecular mechanisms were investigated. Here, we found that LINC00339 expression was aberrantly high in gastric cancer and significantly associated with lymph node metastasis, invasive depth, and TNM stage. Patients with gastric cancer in a LINC00339 high-expression group showed shorter overall survival than patients in a LINC00339 low-expression group. A knockdown of LINC00339 suppressed gastric cancer cell proliferation, migration, and invasion and induced apoptosis in vitro and slowed tumor growth in vivo. In terms of the mechanism, LINC00339 was found to act as a molecular sponge on microRNA-539 (miR-539). SRY-box 9 (SOX9) was confirmed as a direct target gene of miR-539 in gastric cancer cells. An miR-539 knockdown attenuated the effects of the LINC00339 knockdown on the malignant characteristics of gastric cancer cells. Overall, LINC00339 plays a critical role in the malignancy of gastric cancer by regulating SOX9 via sponging of miR‑539. Our findings highlight the importance of the LINC00339-miR-539-SOX9 pathway in gastric cancer pathogenesis and may point to novel targets for the diagnosis, prognosis, and/or treatment of gastric cancer.

LncRNA LINC00483 promotes gastric cancer development through regulating MAPK1 expression by sponging miR-490-3p

Background

Previous studies have shown that long noncoding RNA (lncRNA) LINC00483 was aberrantly expressed in human cancers, including gastric cancer. However, the regulatory mechanism of this lncRNA in gastric cancer remains largely unknown. The present study aimed to investigate the effect of LINC00483 on gastric cancer development and explore the potential regulatory network of LINC00483/microRNA (miR)-490-3p/mitogen-activated protein kinase 1 (MAPK1).

Methods

Thirty patients with gastric cancer were recruited for tissues collection. The expression levels of LINC00483, miR-490-3p and MAPK1 were detected by quantitative real-time polymerase chain reaction or western blot. Cell viability, apoptosis, migration and invasion were determined by MTT, flow cytometry, transwell assays and western blot, respectively. The target association between miR-490-3p and LINC00483 or MAPK1 was confirmed by luciferase reporter assay. Xenograft model was established to assess the function of LINC00483 in vivo.

Results

LINC00483 and MAPK1 levels were increased in gastric cancer tissues and cells. Knockdown of LINC00483 or MAPK1 inhibited cells viability, migration and invasion but promoted apoptosis in gastric cancer cells. Moreover, MAPK1 overexpression attenuated the effect of LINC00483 knockdown on gastric cancer development. LINC00483 could increase MAPK1 expression by competitively sponging miR-490-3p. miR-490-3p overexpression suppressed gastric cancer development, which was abated by introduction of LINC00483. Besides, inhibition of LINC00483 decreased xenograft tumor growth by regulating miR-490-3p/MAPK1 axis.

Conclusion

Knockdown of LINC00483 inhibited gastric cancer development in vitro and in vivo by increasing miR-490-3p and decreasing MAPK1, elucidating a novel mechanism for understanding the development of gastric cancer.

WGCNA Co-Expression Network Analysis Reveals ILF3-AS1 Functions as a CeRNA to Regulate PTBP1 Expression by Sponging miR-29a in Gastric Cancer

Gastric cancer (GC) is one of the most common types of human cancers worldwide. However, the detail mechanisms underlying GC progression remained to be investigated. The present study identified 2823 differently expressed mRNAs and 441 differently expressed lncRNAs in GC. WGCNA was conducted to identify highly correlated lncRNAs and mRNAs. Bioinformatics analysis observed that these dysregulated lncRNAs were significantly associated with the regulation of angiogenesis, cell division, cell-cell adhesion, blood vessel development, adaptive immune response, gastric acid secretion, immune response. Co-expression analysis identified ILF3-AS1 was a key lncRNA involved in regulating GC progression. Loss of function assays showed that knockdown of ILF3-AS1 significantly suppressed GC cell proliferation and metastasis. Mechanically, the results indicate that ILF3-AS1 could enhance PTBP3 expression as an miR-29a sponge, thereby promoting the proliferation and metastasis of GC cells. Our work suggests that the ILF3-AS1/miR-29a/PTBP3 axis may be a potential target for the clinical diagnosis and treatment of GC.

Long Noncoding RNA AFAP1-AS1 Promotes Cell Proliferation and Metastasis via the miR-155-5p/FGF7 Axis and Predicts Poor Prognosis in Gastric Cancer

Background

Actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1) plays an important role in the development and progression of several human cancers. However, its biological function in gastric cancer (GC) progression is still unknown.

Methods

We used qRT-PCR to detect the relative expression of AFAP1-AS1 in GC tissues and cell lines. The loss-of-function assays were conducted to detect the effect of AFAP1-AS1 on GC development. Bioinformatics analysis, luciferase reporter gene analysis, and RIP analysis were used to identify and validate target genes of AFAP1-AS1. Finally, rescue tests were performed to confirm the influence of the AFAP1-AS1-miR-155-5p-FGF7 axis on GC development.

Results

AFAP1-AS1 was upregulated in GC tissues and cell lines and was closely correlated with poor prognosis of GC patients. AFAP1-AS1 knockdown inhibited proliferation, migration, and invasion of GC cells, indicating that AFAP1-AS1 acts as an oncogene in GC. Bioinformatics analysis, dual-luciferase reporter gene detection, and RIP assays validated that AFAP1-AS1 directly interacts to miR-155-5p and could positively affect cell proliferation, migration, and invasion by regulation of the expression of miR-155-5p and FGF7. Further rescue assays revealed that AFAP1-AS1 promotes cell proliferation and metastasis through the miR-155-5p/FGF7 axis in GC.

Conclusions

AFAP1-AS1 might be an oncogenic lncRNA that promoted GC progression by acting as a competing endogenous RNA (ceRNA) that regulates the expression of FGF7 through sponging miR-155-5p, suggesting that AFAP1-AS1 may be a novel potential therapeutic target for GC.

The Long Non-Coding RNA NEAT1 Promotes Gastric Cancer Cell Proliferation and Invasion by Regulating miR-103a/ STAMBPL1 Axis

BACKGROUND

Gastric cancer (GC) is a common malignancy with high morbidity. Long non-coding RNAs (LncRNAs) have been demonstrated to be critical post-transcriptional regulators in tumorigenesis. This study aimed to investigate the effect of LncRNA NEAT1 on the proliferation and metastasis of GC.

MATERIAL AND METHODS

The expression of LncRNA NEAT1 was examined in clinical samples and GC cell lines. GC cell lines (SGC-7901 and BGC-823) and human normal gastric epithelial cell line (GES-1) were employed. The correlation between NEAT1, miR-103a and STAMBPL1 was determined by luciferase reporter assay. Cell viability was determined by CCK8 assay. Cell invasion capacity was examined by Transwell assay. The protein level of STAMBPL1 was analyzed by western blotting.

RESULTS

LncRNA NEAT1 was found to be up-regulated in GC cell lines. Further studies identified LncRNA NEAT1 as a direct target of miR-103a. Moreover, NEAT1 knockdown and miR-103a overexpression inhibited cell proliferation and cell invasion. NEAT1 knockdown and miR-103a overexpression also decreased STAMBPL1 levels.

CONCLUSION

Our study indicated that LncRNA NEAT1 was up-regulated in GC cells and tissues. NEAT1 was targeted and inhibited by miR-103a and acted as an oncogene, which promoted the malignant behavior of GC cells. This regulatory effect of NEAT1 may be associated with STAMBPL1. Therefore, NEAT1 could be used as a biomarker for predicting the progression of GC.

Expression and prognostic analyses of early growth response proteins (EGRs) in human breast carcinoma based on database analysis

Background

Early growth response proteins (EGRs), as a transcriptional regulatory family, are involved in the process of cell growth, differentiation, apoptosis, and even carcinogenesis. However, the role of EGRs in tumors, their expression levels, and their prognostic value remain unclear.

Methods

Using the Oncomine database, Kaplan–Meier Plotter, bcGenExMiner v4.2, cBioPortal, and other tools, the association between the survival data of breast carcinoma (BC) patients and transcriptional levels of four EGRs was investigated.

Results

According to the Oncomine database, in comparison to normal tissues, the expression level of EGR2/3 mRNA in BC tissues was decreased, but there was no difference in the expression level of EGR4 mRNA. On the basis of the Scarff-Bloom-Richardson (SBR) grading system, the downregulated expression level of EGR1/2/3 and upregulated expression level of EGR4 were correlated with an increased histological differentiation level, with significant differences (p < 0.05). Kaplan–Meier curves suggest that a reduction in EGR2/3 mRNA expression is related to recurrence-free survival (RFS) in BC patients. In addition, the mRNA expression level of EGR1/2/3 was related to metastatic relapse-free survival (MRFS) in BC patients with metastatic recurrence (p < 0.05).

Conclusion

EGR1/2/3 can be utilized as an important factor for evaluating prognosis and may be relevant to diagnosis. EGR4 may play a role in the occurrence and development of BC. The specific function and mechanism of EGRs in BC deserve further study.

The regulatory roles and potential prognosis implications of long non-coding RNAs in gastric cancer

Accumulating dysregulated lncRNAs have been demonstrated to execute vital functions in the pathogenesis and progress of gastric cancer (GC) through versatile molecular mechanisms. In this review, we classify the mechanisms of dysregulated lncRNAs in GC into several governing types according to their roles at molecular level. For each regulatory role, we illustrate several instructive examples and introduce significant effects of lncRNAs on cellular biological properties of GC. Besides, we summarize a group of lncRNA-signatures that are potential biomarkers in the prediction of prognosis for GC patients.

Circular RNA circGRAMD1B inhibits gastric cancer progression by sponging miR-130a-3p and regulating PTEN and p21 expression

Circular RNAs (circRNAs) have emerged as essential regulators and biomarkers of various cancers. However, the effects of a novel circRNA termed circGRAMD1B in human gastric cancer (GC) remain unclear. A microarray was used to screen circRNA expression in GC. Quantitative real-time PCR was used to detect the expression of circGRAMD1B. Gain- and loss- of-function experiments were performed to investigate the biological functions of circGRAMD1B in vitro and vivo. Bioinformatics analysis, fluorescence in situ hybridization, dual-luciferase reporter assay, RNA immunoprecipitation, RNA pull-down assay, and rescue experiments were conducted to confirm the underlying mechanisms of competitive endogenous RNAs (ceRNAs). We screened differentially expressed circRNAs and found that circGRAMD1B expression was downregulated in GC tissues and cell lines. Functionally, circGRAMD1B acted as an anti-oncogene and inhibited the proliferation, migration, and invasion abilities of GC cells. Then, we verified that circGRAMD1B served as a sponge that targeted miR-130a-3p in GC cells; circGRAMD1B alleviated GC cell proliferation, migration, and invasion by targeting miR-130a-3p. A mechanistic analysis showed that PTEN and p21 were involved in circGRAMD1B/miR-130a-3p axis-inhibited GC tumorigenesis. Our findings suggest that circGRAMD1B plays an important role in GC progression by regulating miR-130a-3p-PTEN/p21, which may provide a potential biomarker and therapeutic target for GC.

Long noncoding RNA LINC00629 restrains the progression of gastric cancer by upregulating AQP4 through competitively binding to miR-196b-5p

Gastric cancer continues to be a common cancer in the world with high incidence and mortality. Accumulating evidence has implicated long noncoding RNAs (lncRNAs) in gastric cancer progression. Here, this study identified the potential role of a novel lncRNA, LINC00629 in gastric cancer and to elucidate the underlying mechanism. Initially, microarray-based gene expression profiling of gastric cancer was employed to identify differentially expressed genes. Next, the expression of LINC00629, microRNA-196b-5p (miR-196b-5p) and aquaporin 4 (AQP4) in clinical gastric cancer tissues was determined and the cell line presenting with the lowest LINC00629 expression was selected. The interaction among LINC00629, miR-196b-5p, and AQP4 was identified. Expression of LINC00629, miR-196b-5p, and AQP4 in gastric cancer cells were altered and then biological behaviors of gastric cancer cells were assessed by 5-ethynyl-2'-deoxyuridine and Transwell assays. Tumor formation in vivo was evaluated in nude mice. In gastric cancer, expression of LINC00629 and AQP4 was downregulated, and expression of miR-196b-5p was upregulated. Proliferation, invasion, and migration of gastric cancer cells were reduced after overexpression of LINC00629. LINC00629 competitively bound to miR-196b-5p, while AQP4 was a target of miR-196b-5p. Either downregulating miR-196b-5p or upregulating AQP4 could restrain the development of gastric cancer in vitro. LINC00629 overexpression repressed the growth of transplanted tumors in vivo. Taken together, LINC00629 competitively bound to miR-196b-5p to upregulate AQP4 expression, thereby inhibiting gastric cancer progression. Therefore, understanding of this mechanism may help to improve gastric cancer treatment.

LncRNA KCNQ1OT1 acting as a ceRNA for miR-4458 enhances osteosarcoma progression by regulating CCND2 expression

Osteosarcoma is prevalent worldwide and characterized as a challenging health burden. It has been increasingly indicated that long non-coding RNAs (lncRNAs) are significant in pathological processes of numerous cancers, exerting oncogenic or tumor-suppressive function. However, the participation of KCNQ1OT1 in osteosarcoma has not been elaborated. In this study, we focus on interrogating the function of KCNQ1OT1 and its underlying mechanism in osteosarcoma. Our work demonstrated the upregulation of KCNQ1OT1 in osteosarcoma through qRT-PCR. Besides, loss of function assay (CCK-8, transwell migration) indicated KCNQ1OT1 promoted cell proliferation, migration in osteosarcoma. Mechanically, KCNQ1OT1 acting as sponge for miR-4458 antagonized its tumor-suppressive impact on CCND2 expression. The anti-apoptotic nature of KCNQ1OT1 was also unveiled via caspase-3 activity assay. Overexpressed KCNQ1OT1 acted as competing endogenous RNA (ceRNA) for miR-4458 and subsequently reinforced target gene CCND2. Collectively, the results of rescue experiments suggested that the oncogenic role of KCNQ1OT1 was performed through sponging miR-4458 and upregulating CCND2 during osteosarcoma development, providing a novel perspective of intervention in osteosarcoma management.

LncRNA BLACAT1 regulates VASP expression via binding to miR-605-3p and promotes giloma development

Glioma, an aggressive tumor in brain, presents a very poor prognosis. Emerging evidence has demonstrated that dysfunction of long noncoding RNAs (lncRNAs) is closely related to giloma development. However, the roles of lncRNA BLACAT1 in glioma are not unknown. In this study, we utilized in vitro and in vivo experiments to explore the effects of BLACAT1 on glioma cells. BLACAT1 levels were increased in glioma tissues. Upregulation of BLACAT1 showed poor prognosis. Silencing of BLACAT1 markedly repressed glioma proliferation, migration, and invasion, and suppressed glioma growth in vivo. We also illustrated that BLACAT1 worked as the sponge for miR-605-3p and promoted VASP expression. miR-605-3p was downregulated in glioma and repressed glioma proliferation, migration, and invasion. And VASP is upregulated and contributed to glioma progression. Summarily, this study highlights the important roles of BLACAT1/miR-605-3p/VASP axis in glioma progression.