Silencing of LncRNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Inhibits the Proliferation and Promotes the Apoptosis of Gastric Cancer Cells Through Regulating microRNA-22-3p-Mediated ErbB3

A meta-analysis of the clinicopathological significance of the lncRNA MALAT1 in human gastric cancer

Background

Dysregulation of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been linked to some oncogenic pathways that induce cancer initiation and progression. This meta-analysis was conducted to specifically summarize the most recent research on MALAT1 function in human gastric cancer (GC).

Methods

The eligible studies were first identified by searching HowNet, Web of Science, PubMed, The Cochrane Library, Embase, and Nature databases for studies published as of April 1, 2023. The meta-analysis included 14 studies assessing MALAT1 expression and presenting clinical parameters and survival outcomes.

Results

The results illustrated that high MALAT1 expression is predictive of lymph node metastasis (pooled odds ratio [OR] = 2.99, 95% confidence interval [CI] = 1.97-4.54, P < 0.001) and distant metastasis in GC (OR = 3.11, 95% CI = 1.68-5.75, P < 0.001). In addition, MALAT1 was associated with GC tumor invasion (T3/T4 vs. T1/T2: OR = 2.90, 95% CI = 1.90- 4.41, P <0.001) and TNM stage (III/IV vs I/II: OR = 2.93, 95% CI: 1.80-4.77, P <0.001). Additionally, higher MALAT-1 expression predicted poorer overall survival in patients with GC (hazard ratio = 1.64, 95% CI = 1.20-2.09, P < 0.001).

Conclusions

The current findings suggest that the high MALAT1 expression is an adverse biomarker for prognostic outcomes, lymph node metastasis, TNM stage, and distant metastasis in GC and MALAT1 could be a prognostic biomarker for GC.

The Expression Patterns and Implications of MALAT1, MANCR, PSMA3-AS1 and miR-101 in Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is a malignant tumor with poorly understood molecular mechanisms. This study endeavors to elucidate how the long non-coding RNAs (lncRNAs) MALAT1, MANCR and PSMA3-AS1, as well as the microRNA miR-101, exhibit specific expression patterns in the pathogenesis and prognosis of EAC. A total of 50 EAC tissue samples (tumors and lymph nodes) and a control group comprising 26 healthy individuals were recruited. The samples underwent quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. The relative expression levels of MALAT1, MANCR, PSMA3-AS1, and miR-101 were ascertained and correlated with various clinicopathological parameters including TNM staging, tumor characteristics (size and grade of the tumor) lymphatic invasion, disease-free (DFS) and overall survival (OS) of EAC patients. Quantitative analyses revealed that MALAT1 and MANCR were significantly upregulated in EAC tumors and positive lymph nodes when compared to control tissues (p < 0.05). Such dysregulations correlated positively with advanced lymphatic metastases and a higher N stage. DFS in the subgroup of patients with negative lymph nodes was higher in the setting of low-MANCR-expression patients compared to patients with high MANCR expression (p = 0.02). Conversely, miR-101 displayed a significant downregulation in EAC tumors and positive lymph nodes (p < 0.05), and correlated negatively with advanced tumor stage, lymphatic invasion and the grade of the tumor (p = 0.006). Also, patients with low miR-101 expression showed a tendency towards inferior overall survival. PSMA3-AS1 did not demonstrate statistically significant alterations (p > 0.05). This study reveals MALAT1, MANCR, and miR-101 as putative molecular markers for prognostic evaluation in EAC and suggests their involvement in EAC progression.

The emerging role of microRNA-22 in the Leukemia: experimental and clinical implications

MicroRNAs (miRNAs) are short noncoding RNAs, approximately 20-24 nucleotides long that negatively regulate gene expression by either inhibiting translation or cleaving complementary mRNA to participate in various biological processes. Accumulating evidence has indicated that miRNAs are widely present in hematological cancers, particularly leukemia, exhibiting either upregulation or downregulation in leukemia patients compared with healthy controls. These miRNAs have a pivotal role in the development, progression and metastasis of leukemia, as well as in the prognosis and/or relapse of patients. miR-22 is one of the abnormally expressed miRNAs in a variety of leukemia diseases, and is considered to be one of the few cancer suppressors. Recent research has demonstrated that miR-22 is involved in the regulation of leukemia cell proliferation, differentiation and apoptosis, and could be a promising biomarker and prognostic indicator for leukemia. Here, we summarize all relevant findings that carry out experimental investigation and clinical analyses, aiming to elucidate the comprehensive implications of miR-22 in various types of leukemia for the development of new therapeutic and prognostic strategies and new drug targets for the treatment of leukemia.

Metastasis-associated lung adenocarcinoma transcript 1 molecular mechanisms in gastric cancer progression

Gastric cancer (GC) remains among the most common cancers worldwide with a high mortality-to-incidence ratio. Accumulated evidence suggests that long noncoding RNAs (lncRNAs) are involved in gastric carcinogenesis. These transcripts are longer than 200 nucleotides and modulate gene expression at multiple molecular levels, inducing or inhibiting biological processes and diseases. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is one of the best-studied lncRNAs with comprehensive actions contributing to cancer progression. This lncRNA regulates gene expression at the transcriptional and posttranscriptional levels through interactions with microRNAs and proteins. In the present review, we discussed the molecular mechanism of MALAT1 and summarized the current knowledge of its expression in GC. Moreover, we highlighted the potential use of MALAT1 as a biomarker, including liquid biopsy.

Induction of lncRNA MALAT1 by hypoxia promotes bone formation by regulating the miR-22-3p/CEBPD axis

Adaptation to hypoxia promotes fracture healing. However, the underlying molecular mechanism remains unknown. Increasing evidence has indicated that long non-coding RNAs (lncRNAs) play crucial roles in several diseases, including fracture healing. In the present study, lncRNA microarray analysis was performed to assess the expression levels of different lncRNAs in MC3T3-E1 cells cultured under hypoxic conditions. A total of 42 lncRNAs exhibited significant differences in their expression, including metastasis associated lung adenocarcinoma transcript 1 (MALAT1), maternally expressed 3, AK046686, AK033442, small nucleolar RNA host gene 2 and distal-less homeobox 1 splice variant 2. Furthermore, overexpression of MALAT1 promoted osteoblast differentiation, alkaline phosphatase (ALP) activity and matrix mineralization of MC3T3-E1 cells, whereas its knockdown diminished hypoxia-induced cell differentiation, ALP activity and matrix mineralization in these cells. Moreover, functional analysis indicated that MALAT1 regulated the mRNA and protein expression levels of CCAAT/enhancer binding protein δ by competitively binding to microRNA-22-3p. Adenoviral-mediated MALAT1 knockdown inhibited fracture healing in a mouse model. Taken together, the results indicated that MALAT1 may serve a role in hypoxia-mediated osteogenesis and bone formation.

MiR-22-3p suppresses NSCLC cell migration and EMT via targeting RAC1 expression

Previous studies have demonstrated the tumor-suppressive function of microRNA-22-3p (miR-22-3p) in several cancers, whereas the significance of miR-22-3p in non-small cell lung cancer (NSCLC) remains unclear. In this study, we explored the biological function and molecular mechanism of miR-22-3p in NSCLC cells. First, we assessed the expression of miR-22-3p in NSCLC tissues and cells based on RT-qPCR and TCGA database. Compared with normal lung tissues and cells, miR-22-3p expression was dramatically decreased in lung cancer tissues and cells. miR-22-3p expression was also correlated with lymph node metastasis and tumor size, but not TNM stages. We further explored the in vitro function of miR-22-3p on the migration and epithelial-mesenchymal transition (EMT) of NSCLC cells. The results showed that overexpression of miR-22-3p suppressed the migration and EMT of NSCLC cells, whereas silencing miR-22-3p showed the opposite effect. Luciferase assay demonstrated that RAS-related C3 botulinum toxin substrate 1 (RAC1) was the target gene for miR-22-3p. Mechanistically, we demonstrated that miR-22-3p suppressed the cell migration and EMT via downregulation of RAC1 because the inhibitory effect of miR-22-3p on cell migration and EMT of NSCLC cells was reversed by RAC1 overexpression. Based on these novel data, the miR-22-3p/RAC1 axis may be an alternative target in the therapeutic intervention of NSCLC.

Exosomal long noncoding RNAs - the lead thespian behind the regulation, cause and cure of autophagy-related diseases

Recent advances in exosome biology have revealed significant roles of exosome and their contents in intercellular communication. Among various exosomal content, long non-coding RNAs (lncRNAs), which have a large size (˃ 200 nt) and lack protein coding potential, are known to play key roles in intercellular communication and novel biomarkers of various metabolic disorders. Moreover, long non-coding RNAs are often involved in the regulation of various cellular processes such as autophagy, apoptosis, cell proliferation. On the other hand, autophagy is the central regulating point that controls the various metabolic functions of the body. This process is known to prevent diseases and promote longevity. Therefore, the present review discusses the relationship between diseases and autophagy, and also look into the biological functions of exosome-associated lncRNAs in regulating autophagy. Furthermore, this review will summarize some of the studies that provide novel insights into the pathogenesis of autophagy-related diseases followed by the non-canonical roles played by autophagy and related proteins in the development of exosome biogenesis.

Prognostic and immunological significance of metastasis associated lung adenocarcinoma transcript 1 among different kinds of cancers

LncRNAs belong to the type of noncoding RNA transcripts, which exceed 200 nucleotides in size. MALAT1 as one of the earlier identified lncRNAs in cancer is investigated by more and more scientific researchers. Expression, clinical significance and function of MALAT1 in pan-cancer exist as big difference. To detect the expression and clinical significance of MALAT1 gene precisely and comprehensively among different kinds of cancers, some classical databases such as GEPIA, TIMER, KM Plotter, and PrognoScan were fully applied. An immunological role of MALAT1 among different kinds of cancers was also determined in TIMER database. Our results showed that MALAT1 was differently expressed in different kinds of cancers using GEPIA, Oncomine, and TIMER databases to analyze. Especially, MALAT1 high RNA level was related to the early stage in lung and gastric cancer patients. MALAT1 expression was closely related to prognosis among different cancer patients. Furthermore, expression of MALAT1 was related to tumor immune cell infiltrating. Expression level of MALAT1 was also related to immune makers such as macrophage, T cell, NK cells, and so on. These findings indicate that MALAT1 could be a potential prognostic biomarker of some kinds of cancer and was significantly correlated with tumor-infiltrating immune cells in a wide variety of cancers.

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.

Long Noncoding RNA LIT3527 Knockdown induces Apoptosis and Autophagy through inhibiting mTOR pathway in Gastric Cancer Cells

Gastric cancer is one of the most common cancers and the leading causes of cancer mortality. However, the molecular mechanisms of gastric cancer malignancy remain unclear. Long noncoding RNAs (lncRNAs) have been well documented in controlling cancer progression. Identification of critical lncRNAs in gastric cancer will provide new sights into the regulation mechanism of gastric cancer. Here, we screened differentially expressed lncRNAs in gastric cancer tissues and matched adjacent tissues and found that lncRNA LIT3527, a 486-nucleotide (nt) sense transcript, was frequently upregulated in gastric cancer tissues. Knockdown of LIT3527 dramatically suppressed proliferation and migration of gastric cancer cells through inducing severe cell death but not affecting cell cycle. Mechanistically, we uncovered that depletion of LIT35227 induced significant cell apoptosis and autophagy through inhibiting AKT/ERK/mTOR signaling pathway. Targeting LIT3527 showed a robust inhibition of lung metastasis of gastric cancer cells. Taken together, these results suggest that LIT3527 is essential for gastric cancer cell survival through maintaining mTOR activity, suggesting that it may be clinically valuable as a therapeutic target for gastric cancer.

The expression and prognostic value of the epidermal growth factor receptor family in glioma

BACKGROUND

The epidermal growth factor receptor (EGFR) family belongs to the transmembrane protein receptor of the tyrosine kinase I subfamily and has 4 members: EGFR/ERBB1, ERBB2, ERBB3, and ERBB4. The EGFR family is closely related to the occurrence and development of a variety of cancers.

MATERIALS/METHODS

In this study, we used multiple online bioinformatics websites, including ONCOMINE, TCGA, CGGA, TIMER, cBioPortal, GeneMANIA and DAVID, to study the expression profiles, prognostic values and immune infiltration correlations of the EGFR family in glioma.

RESULTS

We found that EGFR and ERBB2 mRNA expression levels were higher in glioblastoma (GBM, WHO IV) than in other grades (WHO grade II & III), while the ERBB3 and ERBB4 mRNA expression levels were the opposite. EGFR and ERBB2 were notably downregulated in IDH mutant gliomas, while ERBB3 and ERBB4 were upregulated, which was associated with a poor prognosis. In addition, correlation analysis between EGFR family expression levels and immune infiltrating levels in glioma showed that EGFR family expression and immune infiltrating levels were significantly correlated. The PPI network of the EGFR family in glioma and enrichment analysis showed that the EGFR family and its interactors mainly participated in the regulation of cell motility, involving integrin receptors and Rho family GTPases.

CONCLUSIONS

In summary, the results of this study indicate that the EGFR family members may become potential therapeutic targets and new prognostic markers for glioma.

Identification of a Novel Prognostic Signature for Gastric Cancer Based on Multiple Level Integration and Global Network Optimization

Gastric Cancer (GC) is a common cancer worldwide with a high morbidity and mortality rate in Asia. Many prognostic signatures from genes and non-coding RNA (ncRNA) levels have been identified by high-throughput expression profiling for GC. To date, there have been no reports on integrated optimization analysis based on the GC global lncRNA-miRNA-mRNA network and the prognostic mechanism has not been studied. In the present work, a Gastric Cancer specific lncRNA-miRNA-mRNA regulatory network (GCsLMM) was constructed based on the ceRNA hypothesis by combining miRNA-target interactions and data on the expression of GC. To mine for novel prognostic signatures associated with GC, we performed topological analysis, a random walk with restart algorithm, in the GCsLMM from three levels, miRNA-, mRNA-, and lncRNA-levels. We further obtained candidate prognostic signatures by calculating the integrated score and analyzed the robustness of these signatures by combination strategy. The biological roles of key candidate signatures were also explored. Finally, we targeted the PHF10 gene and analyzed the expression patterns of PHF10 in independent datasets. The findings of this study will improve our understanding of the competing endogenous RNA (ceRNA) regulatory mechanisms and further facilitate the discovery of novel prognostic biomarkers for GC clinical guidelines.

RETRACTED: Exosomal miR-22-3p from human umbilical cord blood-derived mesenchymal stem cells protects against lipopolysaccharid-induced acute lung injury

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figs. 2D/H/L, and 7B/F, which appear to have the same eyebrow shaped phenotype as many other publications tabulated here (https://docs.google.com/spreadsheets/d/149EjFXVxpwkBXYJOnOHb6RhAqT4a2llhj9LM60MBffM/edit#gid=0). Concerns were also raised over the provenance of the flow cytometry plots in Fig. 1C. The journal requested the corresponding author comment on these concerns and provide the raw data. However the authors were not able to satisfactorily fulfil this request and therefore the Editor-in-Chief decided to retract the article.

Pathways and role of MALAT1 in esophageal and gastric cancer

Esophageal cancer (EC) and gastric cancer (GC) often have an unfavorable prognosis. Therefore, research is being conducted to identify the molecular mechanisms underlying the tumorigenesis and progression of GC and EC, and to indicate novel therapeutic targets and clinically applicable biomarkers. The dysregulations and roles of long non-coding RNAs (lncRNAs) have been widely reported, and current published literature has shown that lncRNAs play important regulatory roles in the carcinogenesis and progression of EC and GC. The lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been investigated in a number of studies with regard to its pathogenic pathways and association with the prognosis of gastric and esophageal malignancies. As literature on the topic of MALAT1 in EC and GC continues to emerge, the present review aims to summarize all current knowledge on the association between MALAT1 expression and esophagogastric malignancies and to describe the pathogenic pathways and possible prognostic role of MALAT1 in esophagogastric cancer. As research studies on MALAT1 pathways in esophagogastric malignancies are ongoing, new possibilities for the diagnosis, prognosis and therapy of GC and EC are likely to be identified.

Association of MALAT1 expression in gastric carcinoma and the significance of its clinicopathologic features in an Iranian patient

AIM

The aim of this study was to evaluate the expression of MALAT1 and the relationship between its expression with clinical characteristics in an Iranian gastric cancer patient.

BACKGROUND

Long non-coding RNAs (LncRNAs) play critical roles in the initiation and development of gastric cancer. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a highly conserved lncRNA and plays key roles in various types of human cancer. However, our understanding of the role of lncRNAs in the occurrence and development of gastric cancer is not fully clear.

METHODS

This cross-sectional study was performed on 41 gastric tumor tissue samples with matched normal adjacent tumor tissues. The RNA level of lncRNA MALAT1 gene was assessed using quantitative Real-time polymerase chain reaction. B2M was used as an internal control. The 2 -ΔΔCq method was adopted to determine expression fold changes.

RESULTS

A significant association was observed between the levels of MALAT1 in gastric tumor tissues compared with normal adjacent tissues (mean= 1.558, p= 0.014). In addition, clinicopathologic data on MALAT1 RNA expression levels in gastric cancer tissues was evaluated. No significant association was observed between the relative expression of MALAT1 and the stage, grade, H. pylori infection, and tumor size groups among gastric cancer patients (p= 0.82, p= 0.904, p= 0.407, and p= 0.701, respectively).

CONCLUSION

The current results showed that MALAT1 has a significant association in gastric cancer. The expression of MALAT1 may be used as a diagnostic biomarker for monitoring gastric cancer patients.

MALAT1 as a Versatile Regulator of Cancer: Overview of the updates from Predatory role as Competitive Endogenous RNA to Mechanistic Insights

The central dogma of molecular biology, has remained a cornerstone of classical molecular biology. However, serendipitously discovered microRNAs (miRNAs) in nematodes paradigmatically shifted our current knowledge of the intricate mechanisms during transitions from transcription to translation. The discovery of miRNA captured considerable attention and appreciation, and we had witnessed an explosion in the field of non-coding RNAs. Ground-breaking discoveries in the field of non-coding RNAs have helped in better characterization of microRNAs and long non-coding RNAs (LncRNAs). There is an ever-increasing list of miRNA targets that are regulated by MALAT1 to stimulate or repress the expression of target genes. However, in this review, our main focus is to summarize mechanistic insights on MALAT1-mediated regulation of oncogenic signaling pathways. We have discussed how MALAT1 modulated TGF/SMAD and Hippo pathways in various cancers. We have also comprehensively summarized how JAK/STAT and Wnt/β-catenin pathways stimulated MALAT1 expression and consequentially how MALAT1 potentiated these signaling cascades to promote cancer. MALAT1 research has undergone substantial broadening. However, there is still a need to identify additional mechanisms. MALAT1 is involved in the multi-layered regulation of multiple transduction cascades, and detailed analysis of different pathways will be advantageous in getting a step closer to individualized medicine.