The functional sites of miRNAs and lncRNAs in gastric carcinogenesis

The role of dysregulated metabolism and associated genes in gastric cancer initiation and development

The review delves into the intricate interplay between metabolic dysregulation and the onset and progression of gastric cancer (GC), shedding light on a pivotal aspect of this prevalent malignancy. GC stands as one of the leading causes of cancer-related mortality worldwide, its trajectory influenced by a multitude of factors, among which metabolic dysregulation and aberrant gene expression play significant roles. The article navigates through the fundamental roles of metabolic dysregulation in the genesis of GC, unveiling phenomena such as aberrant glycolysis, epitomized by the Warburg effect, alongside anomalies in lipid and amino acid metabolism. It delineates how these disruptions fuel the cancerous process, facilitating uncontrolled cell proliferation and survival. Furthermore, the intricate nexus between metabolism and the vitality of GC cells is elucidated, underscoring the profound influence of metabolic reprogramming on tumor energy dynamics and the accrual of metabolic by-products, which further perpetuate malignant growth. A pivotal segment of the review entails an exploration of key metabolic-related genes implicated in GC pathogenesis. MYC and TP53 are spotlighted among others, delineating their pivotal roles in driving tumorigenesis through metabolic pathway modulation. These genetic pathways serve as critical nodes in the intricate network orchestrating GC development, providing valuable targets for therapeutic intervention. This review embarks on a forward-looking trajectory, delineating the potential therapeutic avenues stemming from insights into metabolic dysregulation in GC. It underscores the promise of targeted therapies directed towards specific metabolic pathways implicated in tumor progression, alongside the burgeoning potential of combination therapy strategies leveraging both metabolic and conventional anti-cancer modalities. In essence, this comprehensive review serves as a beacon, illuminating the intricate landscape of metabolic dysregulation in GC pathogenesis. Through its nuanced exploration of metabolic aberrations and their genetic underpinnings, it not only enriches our understanding of GC biology but also unveils novel therapeutic vistas poised to revolutionize its clinical management.

Long non-coding RNAs and gastric cancer: An update of potential biomarkers and therapeutic applications

The frequent metastasis of gastric cancer (GC) complicates the cure and therefore the development of effective diagnostic and therapeutic approaches is urgently necessary. In recent years, lncRNA has emerged as a drug target in the treatment of GC, particularly in the areas of cancer immunity, cancer metabolism, and cancer metastasis. This has led to the demonstration of the importance of these RNAs as prognostic, diagnostic and therapeutic agents. In this review, we provide an overview of the biological activities of lncRNAs in GC development and update the latest pathological activities, prognostic and diagnostic strategies, and therapeutic options for GC-related lncRNAs.

Inhibition of miR-652-3p Regulates Lipid Metabolism and Inflammatory Cytokine Secretion of Macrophages to Alleviate Atherosclerosis by Improving TP53 Expression

Purpose

The aim was to elucidate the regulatory function of miR-652-3p on lipid metabolism and inflammatory cytokine secretion of macrophages in atherosclerosis.

Methods

miR-652-3p level in atherosclerosis patients, ox-LDL-treated macrophages, and their controls were monitored by Q-PCR. After ox-LDL treatment and miR-652-3p mimic, si-TP53 and their controls transfection, ELISA, and Q-PCR assays were used to detect IL-1ß, IL-6, and TNF-α levels. oil red O staining was processed to verify cholesterol accumulation. CE/TC and lipid metabolism were also detected. The protein levels of ABCA1, ABCG1, PPARα, CRT1, ADRP, and ALBP were detected by western blot assay. Based on the TargetScan database, the TP53 3′UTR region had complementary bases with miR-652-3p, which was also verified by dual-luciferase reporter gene assay. Finally, the regulation of miR-652-3p and TP53 was confirmed by rescue assay in atherosclerosis.

Results

miR-652-3p is highly expressed in atherosclerosis, miR-652-3p inhibitor decreased IL-1β, IL-6, and TNF-α expression after ox-LDL treatment. Knockdown of miR-652-3p reduces foam formation in ox-LDL-treated macrophages. miR-652-3p inhibitor ameliorates cholesterol accumulation and lipid metabolism disorder. miR-652-3p negatively regulated TP53 in atherosclerosis. Si-TP53 rescued the effect of miR-652 inhibitor in atherosclerosis.

Conclusion

miR-652-3p regulates the lipid metabolism of macrophages to alleviate atherosclerosis by inhibiting TP53 expression. It might be a potential target for atherosclerosis treatment.

Association between long non-coding RNA H19 polymorphisms and breast cancer risk: a meta-analysis

Common genes mutation was demonstrated associating with the risk of breast cancer (BC) recently, while the role of long non-coding RNA (lncRNA) polymorphism is still controversial. A meta-analysis was designed to discuss the association between lncRNA H19 polymorphisms and susceptibility to BC. The related databases were systematically reviewed up to April 13, 2021. Estimates were summarized as ORs and 95 percent CIs for each included study. The heterogeneity was assessed by the I² test and subgroup analysis. Ten studies with 10354 BC patients and 11,177 control cases were included in our study. LncRNA H19 single nucleotide polymorphism (SNP) rs2839698 C/T significantly increases the susceptibility of BC (OR = 1.717 , 95 percent CI = 1.052-2.803, P = 0.031). LncRNA H19 polymorphism rs3741219 and rs217727 also increase the risk of ER-positive BC (OR = 1.128 , 95 percent CI = 1.010-1.259, P = 0.0032 for rs3741219, and OR = 1.297, 95 percent CI = 1.027-1.639, P = 0.029 for rs217727). Our results demonstrated that lncRNA H19 SNP rs2839698 C/T was significantly associated with the susceptibility of BC. LncRNA H19 SNP rs217727 and rs3741219 were associated with the risks of ER-positive BC. However, further studies are needed to reach a robust conclusion.

Long non-coding RNA HCG18 promotes gastric cancer progression by regulating miRNA-146a-5p/tumor necrosis factor receptor-associated factor 6 axis

Although long non-coding RNAs (lncRNAs) have been demonstrated to be dysregulated in gastric cancer (GC), the function of lncRNA HCG18 (HCG18) in GC is elusive. Therefore, the study was designed to evaluate the underlying mechanism of HCG18 in GC. HCG18 and microRNA 146a-5p (miR-146a-5p) levels in GC were evaluated by RT-qPCR. The effects of miR-146a-5p and HCG18 on GC cell function were examined using Transwell assay, colony formation, and CCK-8 assays. Tumor necrosis factor receptor-associated factor 6 (TRAF6) and p65 expression levels were detected by Western blot. HCG18 and miR-146a-5p target genes were identified using luciferase reporter and bioinformatics assays. HCG18 expression was increased in GC. HCG18 overexpression significantly increased GC cell proliferation, invasion, and migration. Furthermore, HCG18 overexpression inhibited miR-146a-5p and upregulated TRAF6 and p65 expression. Finally, miR-146a-5p/TRAF6 was found to be involved in the role of HCG18 in GC progression in vivo. Altogether, HCG18 promotes GC progression via the miR-146a-5p/TRAF6 axis and could be a GC treatment target.

miRNAs in Cancer (Review of Literature)

MicroRNAs (miRNAs) are short, noncoding, single-stranded RNA molecules that regulate gene expression at the post-transcriptional level by binding to mRNAs. miRNAs affect the course of processes of fundamental importance for the proper functioning of the organism. These processes include cell division, proliferation, differentiation, cell apoptosis and the formation of blood vessels. Altered expression of individual miRNAs has been shown in numerous cancers, which may indicate the oncogenic or suppressor potential of the molecules in question. This paper discusses the current knowledge about the possibility of using miRNA as a diagnostic marker and a potential target in modern anticancer therapies.

A multiplexed, automated immuno-matrix assisted laser desorption/ionization mass spectrometry assay for simultaneous and precise quantitation of PTEN and p110α in cell lines and tumor tissues

The PI3-kinase/AKT/mTOR pathway plays a central role in cancer signaling. While p110α is the catalytic α-subunit of PI3-kinase and a major drug target, PTEN is the main negative regulator of the PI3-kinase/AKT/mTOR pathway. PTEN is often down-regulated in cancer, and there are conflicting data on PTEN's role as breast cancer biomarker. PTEN and p110α protein expression in tumors is commonly analyzed by immunohistochemistry, which suffers from poor multiplexing capacity, poor standardization, and antibody crossreactivity, and which provides only semi-quantitative data. Here, we present an automated, and standardized immuno-matrix-assisted laser desorption/ionization mass spectrometry (iMALDI) assay that allows precise and multiplexed quantitation of PTEN and p110α concentrations, without the limitations of immunohistochemistry. Our iMALDI assay only requires a low-cost benchtop MALDI-TOF mass spectrometer, which simplifies clinical translation. We validated our assay's precision and accuracy, with simultaneous enrichment of both target proteins not significantly affecting the precision and accuracy of the quantitation when compared to the PTEN- and p110α-singleplex iMALDI assays (<15% difference). The multiplexed assay's linear range is from 0.6-20 fmol with accuracies of 90-112% for both target proteins, and the assay is free of matrix-related interferences. The inter-day reproducibility over 5-days was high, with an overall CV of 9%. PTEN and p110α protein concentrations can be quantified down to 1.4 fmol and 0.6 fmol per 10 μg of total tumor protein, respectively, in various tumor tissue samples, including fresh-frozen breast tumors and colorectal cancer liver metastases, and patient-derived xenograft (PDX) tumors.

MiR-200c-3p aggravates gastric cell carcinoma via KLF6

Background

Gastric cell carcinoma (GCC) is a common and high-incidence malignant gastrointestinal cancer that seriously threatens human life and safety. Evidences suggest that microRNAs (miRNAs) exhibit an essential role in regulating the occurrence and development of GCC, while the effects and possible mechanisms remain to be further explored.

Objective

This study was designed to explore whether miR-200c-3p exerted its functional role in the growth and metastasis of GCC, and investigate the possible mechanisms.

Methods

The expression levels of miR-200c-3p in GCC tissues and cell lines were detected by qRT-PCR analysis. The functional role of miR-200c-3p in the viability, proliferation, migration and invasion of GCC cells were evaluated by CCK-8, EdU, wound healing and Transwell assays. In addition, the candidate targets of miR-200c-3p was predicted and confirmed by dual-luciferase reporter assay. Moreover, the relationship between miR-200c-3p and target (Krüppel like factor 6, KLF6) was assessed by qRT-PCR and western blot assays. Besides, the expression levels of KLF6 in GCC cells were determined by qRT-PCR and western blot assays. Furthermore, the role of KLF6 in the viability, proliferation, migration and invasion of GCC cells mediated with miR-200c-3p mimics was evaluated by CCK-8, EdU, wound healing and Transwell assays.

Results

In the present study, a new tumor promoting function of miR-200c-3p was disclosed in GCC. We found that the expression of miR-200c-3p was obviously increased in clinic GCC tissues and cell lines. In addition, down-regulation of miR-200c-3p suppressed cell viability, proliferation, migration, and invasion in GCC cells. Moreover, KLF6 was verified as a direct target of miR-200c-3p by binding its 3’-UTR. Additionally, KLF6 was remarkably decreased and was negatively associated with the miR-200c-3p expression in GCC cell lines. Furthermore, over-expression of KLF6 retarded the effects of miR-200c-3p on the growth and metastasis of GCC cell lines.

Conclusions

MiR-200c-3p potentially played a tumor-promoting role in the occurrence and development of GCC, which may be achieved by targeting KLF6.

Graphic abstract

The role of long noncoding RNAs in regulating invasion and metastasis of malignant tumors

Long noncoding RNAs (lncRNAs) are a group of non-protein-coding transcripts exceeding 200 nucleotides in length, which are emerging as key players in various fundamental biological processes. Furthermore, it is increasingly recognized that mutation and dysregulation of lncRNAs contribute importantly to a variety of human diseases, particularly human cancers. Previous studies have revealed that altered lncRNAs have a close association with tumorigenesis, metastasis, prognosis and diagnosis of cancers. The present review aims to exhibit a brief overview of the associated reports of lncRNAs in cancers, including colorectal cancer, gastric cancer, lung adenocarcinoma, nasopharyngeal carcinoma, cervical cancer and esophageal cancer. Altogether, we argue that lncRNAs have potential as new biomarkers in cancer prognosis and diagnosis, and as promising therapeutic targets for the prevention and treatment of human cancers.

Long Noncoding RNA H19 Induces Neuropathic Pain by Upregulating Cyclin-Dependent Kinase 5-Mediated Phosphorylation of cAMP Response Element Binding Protein

Objective

Neuropathic pain (NP) is a debilitating condition caused by nervous system injury and chronic diseases. LncRNA H19 is upregulated in many human diseases, including NP. Cyclin-dependent kinase 5 (CDK5) aggressively worsens inflammatory action and nerve damage to cause severe NP. Phosphorylated cAMP response element binding protein (CREB) is detrimental to nerves and promotes NP progression. Herein, aim of our study was to assess the mechanism of lncRNA H19.

Methods

The NP rat model was established using chronic constriction injury (CCI). Paw withdrawal threshold (PWT) tests and paw withdrawal latency (PWL) tests were performed. Then, small interfering (si)RNA against H19 was intrathecally injected into rats to suppress H19 expression. Schwann cells were isolated from NP rats and transfected with siRNA-H19 or a lentivirus (LV)-based vector expressing H19. Inflammatory factors and glial fibrillary acidic protein (GFAP) were detected. Western blot analysis was conducted to detect CDK5/p35 and p-CREB expression. Finally, H19, CDK5 and CREB phosphorylation were tested with the combination of the CDK5 inhibitor roscovitine and transfection of LV-H19 and siRNA-H19. Finally, we investigated the binding relationships between H19 and miR-196a-5p and between miR-196a-5p and CDK5 and detected the mRNA expression of miR-196a-5p and CDK5 in rats with H19 knockdown and in Schwann cells with H19 knockdown.

Results

Highly expressed H19, CDK5/p-35 and p-CREB were observed in NP rats, accompanied by obviously decreased PWT and PWL, upregulated inflammatory factors and GFAP levels, and reduced 5-HT_2A and GABA_B2 expression. siRNA-H19 restored NP-related indexes and downregulated CDK5/p35 and p-CREB phosphorylation. siRNA-H19, together with the CDK5 inhibitor roscovitine, reduced CDK5 and p-CREB expression in Schwann cells isolated from NP rats. Binding sites between H19 and miR-196a-5p and between miR-196a-5p and CDK5 were identified. Silencing H19 upregulated miR-196a-5p expression and downregulated CDK5 levels.

Conclusion

Our study demonstrated that silencing H19 inhibited NP by suppressing CDK5/p35 and p-CREB phosphorylation via the miR-196a-5p/CDK5 axis, which may provide new insight into NP treatment.

Downregulation of LINC00958 inhibits proliferation, invasion and migration, and promotes apoptosis of colorectal cancer cells by targeting miR‑3619‑5p

The aberrant expression of long non-coding RNAs (lncRNAs), including LINC00958, has been demonstrated in several types cancers. The present study aimed to investigate the role of LINC00958 in colorectal cancer (CRC) and identify the possible underlying mechanisms. The expression of LINC00958 and microRNA (miR)-3619-5p was detected in several human CRC cell lines using reverse transcription-quantitative PCR. Then, short hairpin RNA (shRNA)-LINC00958 was transfected into the cells. The results revealed that the expression of LINC00958 was notably upregulated, whereas miR-3619-5p was downregulated in CRC cells. Transfection with shRNA-LINC00958 inhibited the proliferation, invasion and migration of CRC cells. Moreover, the rate of apoptosis was enhanced, accompanied by a decrease in the expression of Bcl-2 and an increase in the expression of Bax and caspase-3. A luciferase reporter assay was conducted to verify the target binding site between LINC00958 and miR-3619-5p. The luciferase reporter assay confirmed that miR-3619-5p could be directly targeted by LINC00958. Furthermore, the miR-3619-5p inhibitor reversed the effects of LINC00958 silencing on proliferation, invasion, migration and apoptosis. Taken together, the findings suggest that the downregulation of LINC00958 suppresses the proliferation, invasion and migration, and promotes the apoptosis of CRC cells by targeting miR-3619-5p in vitro, which provides a theoretical basis and therapeutic strategy for the treatment of CRC.

Long Intergenic Non-Protein Coding RNA 1089 Suppresses Cell Proliferation and Metastasis in Gastric Cancer by Regulating miRNA-27a-3p/Epithelial-Mesenchymal Transition (EMT) Axis

Aim

To explore the expression and biological function of long intergenic non-protein coding RNA 1089 (LINC01089) in gastric cancer (GC) progression and its underlying mechanism.

Methods

LINC01089 and microRNA-27a-3p (miR-27a-3p) expressions were detected with the quantitative real-time polymerase chain reaction (RT-qPCR). Cell proliferation, migration and invasion were evaluated by Cell Counting Kit-8 (CCK-8) and Transwell assay. Epithelial-mesenchymal transition (EMT)-related proteins were also measured by Western blot. The relationship between LINC01089 and miR-27a-3p was revealed by a bioinformatics analysis and dual-luciferase reporter assay.

Results

LINC01089 was significantly down-regulated in GC tissues, as well as GC cell lines. GC patients with lower LINC01089 expression were more likely to have poor outcomes. Overexpression of LINC01089 significantly suppressed GC cells growth, migration and invasion and forbade the EMT process. LINC01089 was directly targeted at miR-27a-3p. The transfection of miR-27a-3p mimics reversed the inhibitory effects on proliferative and metastatic abilities of GC cells with LINC01089 overexpression.

Conclusion

LINC01089 inhibits cell proliferation and metastasis in GC by targeting miR-27a-3p/EMT axis, which should be considered as a promising therapeutic target.

HIF1A activates the transcription of lncRNA RAET1K to modulate hypoxia-induced glycolysis in hepatocellular carcinoma cells via miR-100-5p

Hepatocellular carcinoma (HCC) remains the primary cause of cancer-related death. Metabolic change is the major characteristic of cancer. The present study attempted to investigate the regulatory mechanisms of HCC energy metabolism from the perspective of noncoding RNA regulation of HIF1A and LDHA. The expression of miR-100-5p expression was significantly suppressed in HCC tissue samples and HCC cell lines under 1% O₂-induced hypoxia. miR-100-5p overexpression significantly suppressed hypoxia-induced increases in lactate concentration and glucose uptake. Exposure to 1% O₂ induced HIF1A protein and reduced miR-100-5p expression, while HIF1A silencing dramatically rescued miR-100-5p expression upon 1% O₂ exposure. In addition, 1% O₂-induced increases in lactate concentration and glucose uptake were also suppressed by HIF1A silencing. Next, by analyzing available data in TCGA, we found that lncRNA RAET1K was correlated with HIF1A and miR-100-5p.LncRNA RAET1K could downregulate the expression of miR-100-5p by acting as a sponge, while HIF1A bound the lncRNA RAET1K promoter region to activate its transcription. LncRNA RAET1K silencing significantly suppressed HCC cell proliferation and invasion and also suppressed hypoxia-induced increases in lactate concentration and glucose uptake, while miR-100-5p inhibition reversed the effects of lncRNA RAET1K silencing on hypoxia-induced glycolysis in HCC cells. Finally, the expression of HIF1A, lncRNA RAET1K, and LDHA was upregulated in HCC tissue specimens; the expression of miR-100-5p was negatively related to HIF1A, lncRNA RAET1K, and LDHA; and HIF1A, lncRNA RAET1K, and LDHA were positively correlated with each other. In conclusion, the HIF1A/lncRNA RAET1K/miR-100-5p axis modulates hypoxia-induced glycolysis in HCC cells and might affect HCC progression.

LncRNA NORAD Promotes Proliferation And Inhibits Apoptosis Of Gastric Cancer By Regulating miR-214/Akt/mTOR Axis

PURPOSE

In previous studies, we confirmed that the overexpression of lncRNA NORAD was associated with the occurrence and development of gastric cancer (GC). The aim of the present study was to explore the molecular mechanism of lncRNA NORAD on GC cell proliferation and apoptosis in vitro and in vivo.

PATIENTS AND METHODS

The quantitative Real-Time PCR (qRT-PCR) was used to determine the expression levels of lncRNA NORAD and miR-214 in GC tissues and cells. The interaction between lncRNA NORAD and miR-214 was investigated by biological information and Dual-Luciferase gene reporter assay. Effect of lncRNA NORAD on GC tumor growth in vivo was studied in tumor xenograft model mice. The apoptosis of GC cells was determined by flow cytometry. The proliferation of GC cells was determined by 5-ethynyl-2´-deoxyuridine (EDU) and colony formation assays. Western Blot was used to determine the expressions of caspase-3, Akt and mTOR in GC tissues and cells.

RESULTS

The qRT-PCR results showed that lncRNA NORAD was highly expressed in human GC tissues and cell lines, while miR-214 was significantly down-regulated. Meanwhile, there was a direct interaction between lncRNA NORAD and miR-214. In addition, lncRNA NORAD could promote the growth and proliferation of GC cells both in vivo and in vitro. NOARD could also inhibit the apoptosis of GC cells by down-regulating caspase-3; however, miR-214 overexpression attenuated this effect. Moreover, lncRNA NORAD promoted the phosphorylation of Akt and mTOR in mouse GC tissues and GC cell lines, while miR-214 mimics inhibited that promotion.

CONCLUSION

These results suggested that NORAD could promote the development of GC by inhibiting miR-214 expression and activating the Akt/mTOR signaling pathway.

Gastric Mucosal Microarchitectures Associated with Irreversibility with Helicobacter pylori Eradication and Downregulation of Micro RNA (miR)-124a

To investigate the molecular mechanisms of gastric carcinogenesis after Helicobacter pylori (H. pylori) eradication, expression of miR-124a, miR-34b, and miR-34c was examined in nonneoplastic gastric specimens after successful H. pylori eradication. The magnifying narrow-band imaging (NBI) endoscopic features of gastric mucosa were also examined. The atrophic type, an informative endoscopic feature for histological intestinal metaplasia, showed lower expression of miR-124a. Lower expression of miR-124a correlated with hypermethylation of the miR-124a3 locus. The atrophic type represents gastric microarchitectures associated with irreversibility with H. pylori eradication and downregulation of miR-124a.

Aberrant NEAT1_1 expression may be a predictive marker of poor prognosis in diffuse large B cell lymphoma

BACKGROUND

Many studies have demonstrated that the long non-coding RNA (lncRNA), NEAT1_1, plays critical roles in various human tumor entities and is related to the survival of patients with malignancies. However, the role of NEAT1_1 in diffuse large B cell lymphoma (DLBCL) remains unclear. The aim of this study was to investigate the role of NEAT1_1 in DLBCL.

METHODS

The expression of NEAT1_1 was evaluated in paraffin-embedded tissues from 64 DLBCL patients and 15 lymphnoditis patients using the ISH method. The correlations between the expression levels of NEAT1_1 and clinical-pathological features and patients' survival were also analyzed. After knocking down NEAT1_1 using shRNA in the DLBCL cell lines OCI-Ly1 and SUDHL-4, cell viability, apoptosis and migration were assessed by performing CCK8 assays, annexin V-FITC/PI double staining assays and migration filter assays, respectively.

RESULTS

NEAT1_1 expression was increased in DLBCL tissue compared to lymphnoditis tissue samples (P< 0.001). The NEAT1_1 level was positively related to stage (P= 0.031), IPI (P= 0.017), extranodal site involvement (P= 0.042) and drug response (P= 0.040). Kaplan-Meier analysis showed that high expression levels of NEAT1_1 were correlated with a poor prognosis in DLBCL patients. After shRNA-NEAT1_1 was transfected into OCI-Ly1 and SUDHL-4 for 24 h, the NEAT1_1 level decreased to approximately one-third the level of the control. Moreover, the viability and migration ability of the DLBCL cell lines were significantly suppressed. shRNA-NEAT1_1 induced apoptosis in both DLBCL cell lines.

CONCLUSIONS

Our results showed that NEAT1_1 plays an oncogenic role in DLBCL. NEAT1_1 expression may serve as a predictive marker for DLBCL patients.

LncRNA PICART1 suppressed non-small cell lung cancer cells proliferation and invasion by targeting AKT1 signaling pathway

LncRNAs play significant roles in various cell biological processes. In the present study, we demonstrated that PICART1 expression was down-regulated in non-small cell lung cancer (NSCLC) tissues. Lower expression level of PICART1 was associated with advanced stage. In addition, PICART1 expression was down-regulated in NSCLC cell lines. Overexpression of PICART1 inhibited NSCLC cell growth and induced cell cycle arrest at G2/M phase. Elevated expression of PICART1 suppressed NSCLC cell colony formation and cell invasion. Ectopic expression of PICART1 promoted the expression of epithelial marker E-cadherin while suppressed the mesenchymal marker expression such as N-cadherin and Snail and Vimentin. Furthermore, PICART1 overexpression suppressed AKT phosphorylation and c-Myc expression while inhibited the p21 expression in NSCLC cell. AKT phosphorylation was involved in PICART1 mediated suppression of cell growth and invasion. These results suggested that overexpression of PICART1 suppressed cell growth and invasion partly through regulating AKT signaling pathway in NSCLC.

Knockdown of long non-coding RNA ANRIL inhibits tumorigenesis in human gastric cancer cells via microRNA-99a-mediated down-regulation of BMI1

Long non-coding RNA antisense non-coding RNA in the INK4 locus (ANRIL) has been reported to promote tumorigenesis via regulating microRNA (miR)-99a in gastric cancer cells. However, the role of each component involved in it is still not well understood. This study aimed to verify the role of ANRIL in gastric cancer as well as the underlying mechanisms. ANRIL levels in clinical gastric cancer tissues and cell lines were tested by qPCR. Effects of ANRIL silence on cell viability, migration and invasion, apoptosis, and miR-99a expression in MKN-45 and SGC-7901 cells were measured using CCK-8, Transwell assay, flow cytometry, and qPCR assays, respectively. Then, effects of miR-99a inhibition on ANRIL-silenced cells were evaluated. B-lymphoma Mo-MLV insertion region 1 (BMI1) expression, after abnormal expression of ANRIL and miR-99a, was determined. Finally, expression of key proteins in the apoptotic, Notch, and mTOR pathways was assessed. ANRIL level was elevated in gastric cancer tissues and cell lines. Knockdown of ANRIL suppressed cell viability, migration, and invasion, and increased apoptosis through up-regulating miR-99a. Furthermore, ANRIL silence down-regulated BMI1 via up-regulating miR-99a. BMI1 silence down-regulated Bcl-2 and key kinases in the Notch and mTOR pathways and up-regulated p16 and cleaved caspases. We verified the tumor suppressive effects of ANRIL knockdown in gastric cancer cells via crosstalk with miR-99a. Together, we provided a novel regulatory mechanism for ANRIL in gastric cancer, in which ANRIL silence down-regulated BMI1 via miR-99a, along with activation of the apoptotic pathway and inhibition of the Notch and mTOR pathways.

Long non-coding RNAs: crucial regulators of gastrointestinal cancer cell proliferation

Studies of long non-coding RNAs (lncRNAs) have been prevalent in the field of non-coding RNA regulation in recent years. LncRNAs exert crucial effects on malignant cell processes in the gastrointestinal system, including proliferation. Aberrant lncRNA expression, through both oncogenes and tumor suppressor genes, is instrumental to tumor cell proliferation. Here, we summarize the different molecular mechanisms and relevant signaling pathways through which multifarious lncRNAs regulate cell proliferation and we show that lncRNAs are potential biomarkers for gastrointestinal cancers.

Long non-coding RNA H19 regulates viability and metastasis, and is upregulated in retinoblastoma

Retinoblastoma is the most common type of intraocular pediatric malignant tumor, which typically affects children <6 years of age. However, the underlying molecular mechanisms of retinoblastoma progression remain unclear. The aim of the present study was to investigate the function of long non-coding RNA (lncRNA) H19 in retinoblastoma clinical samples and cell lines, using reverse transcription-quantitative polymerase chain reaction, western blotting, colony formation, MTT, fluorescence activated cell sorting, cell invasion and migration, and in vivo growth assays. The results demonstrated that H19 may serve a critical oncogenic function in the progression of retinoblastoma, as lncRNA H19 levels were markedly increased in retinoblastoma cells and tissues compared with corresponding controls. In addition, patients with retinoblastoma with increased lncRNA H19 expression experienced poorer survival time compared with those with decreased lncRNA H19 levels. Knockdown of lncRNA H19 significantly suppressed retinoblastoma cell proliferation, migration and invasion in vitro and in vivo. Furthermore, lncRNA H19 expression was also associated with multiple proteins, including cyclin-dependent kinase 1, B-cell lymphoma-associated X protein, apoptosis regulator, tumor protein p53, vimentin, cadherin 13 and matrix metallopeptidase 9. In conclusion, lncRNA H19 may serve an important function in tumorigenesis and may be a potential target for therapy and prognosis in retinoblastoma.

Integration of lncRNA and mRNA Transcriptome Analyses Reveals Genes and Pathways Potentially Involved in Calf Intestinal Growth and Development during the Early Weeks of Life

A better understanding of the factors that regulate growth and immune response of the gastrointestinal tract (GIT) of calves will promote informed management practices in calf rearing. This study aimed to explore genomics (messenger RNA (mRNA)) and epigenomics (long non-coding RNA (lncRNA)) mechanisms regulating the development of the rumen and ileum in calves. Thirty-two calves (≈5-days-old) were reared for 96 days following standard procedures. Sixteen calves were humanely euthanized on experiment day 33 (D33) (pre-weaning) and another 16 on D96 (post-weaning) for collection of ileum and rumen tissues. RNA from tissues was subjected to next generation sequencing and 3310 and 4217 mRNAs were differentially expressed (DE) between D33 and D96 in ileum and rumen tissues, respectively. Gene ontology and pathways enrichment of DE genes confirmed their roles in developmental processes, immunity and lipid metabolism. A total of 1568 (63 known and 1505 novel) and 4243 (88 known and 4155 novel) lncRNAs were detected in ileum and rumen tissues, respectively. Cis target gene analysis identified BMPR1A, an important gene for a GIT disease (juvenile polyposis syndrome) in humans, as a candidate cis target gene for lncRNAs in both tissues. LncRNA cis target gene enrichment suggested that lncRNAs might regulate growth and development in both tissues as well as posttranscriptional gene silencing by RNA or microRNA processing in rumen, or disease resistance mechanisms in ileum. This study provides a catalog of bovine lncRNAs and set a baseline for exploring their functions in calf GIT development.

MicroRNA-124-3p expression and its prospective functional pathways in hepatocellular carcinoma: A quantitative polymerase chain reaction, gene expression omnibus and bioinformatics study

The present study aimed to explore the potential clinical significance of microRNA (miR)-124-3p expression in the hepatocarcinogenesis and development of hepatocellular carcinoma (HCC), as well as the potential target genes of functional HCC pathways. Reverse transcription-quantitative polymerase chain reaction was performed to evaluate the expression of miR-124-3p in 101 HCC and adjacent non-cancerous tissue samples. Additionally, the association between miR-124-3p expression and clinical parameters was also analyzed. Differentially expressed genes identified following miR-124-3p transfection, the prospective target genes predicted in silico and the key genes of HCC obtained from Natural Language Processing (NLP) were integrated to obtain potential target genes of miR-124-3p in HCC. Relevant signaling pathways were assessed with protein-protein interaction (PPI) networks, Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Protein Annotation Through Evolutionary Relationships (PANTHER) pathway enrichment analysis. miR-124-3p expression was significantly reduced in HCC tissues compared with expression in adjacent non-cancerous liver tissues. In HCC, miR-124-3p was demonstrated to be associated with clinical stage. The mean survival time of the low miR-124-3p expression group was reduced compared with that of the high expression group. A total of 132 genes overlapped from differentially expressed genes, miR-124-3p predicted target genes and NLP identified genes. PPI network construction revealed a total of 109 nodes and 386 edges, and 20 key genes were identified. The major enriched terms of three GO categories included regulation of cell proliferation, positive regulation of cellular biosynthetic processes, cell leading edge, cytosol and cell projection, protein kinase activity, transcription activator activity and enzyme binding. KEGG analysis revealed pancreatic cancer, prostate cancer and non-small cell lung cancer as the top three terms. Angiogenesis, the endothelial growth factor receptor signaling pathway and the fibroblast growth factor signaling pathway were identified as the most significant terms in the PANTHER pathway analysis. The present study confirmed that miR-124-3p acts as a tumor suppressor in HCC. miR-124-3p may target multiple genes, exerting its effect spatiotemporally, or in combination with a diverse range of processes in HCC. Functional characterization of miR-124-3p targets will offer novel insight into the molecular changes that occur in HCC progression.

lncRNA BG981369 Inhibits Cell Proliferation, Migration, and Invasion, and Promotes Cell Apoptosis by SRY-Related High-Mobility Group Box 4 (SOX4) Signaling Pathway in Human Gastric Cancer

Background

Human gastric cancer (GC) is a leading primary cause of cancer-associated deaths in both males and females worldwide. However, there are few effective diagnostic and therapeutic measures for GC patients due to the complicated underlying mechanisms of GC. Recently, increasing research has indicated that lncRNAs may play a critical role in the progression of GC.

Material/Methods

AI769947, AK054978, DB077273, BG981369, AK054588, and AF131784 expressions were analyzed by qRT-PCR assay in GC tissues and corresponding normal tissues (n=44). BG981369 expression was detected by qRT-PCR assay in GC cells. BG981369 was overexpressed and silenced in AGS and SNU-5 cells. The proliferation ability was detected by MTT and colony formation assays. Cell cycle distribution and cell apoptosis rate were analyzed by flow cytometry. The migration and invasion abilities were measured by Transwell assay. In addition, SOX4 expression was analyzed by qRT-PCR in GC tissues. The correlation between SOX4 and BG981369 was analyzed by Pearson analysis.

Results

The results indicated that lncRNA BG981369 was significantly higher in GC tissues than in normal tissues. Overexpression of BG981369 inhibited the proliferation, migration, and invasion and promoted apoptosis of gastric adenocarcinoma (AGS) cells, and silencing of BG981369 promoted proliferation, migration, and invasion, and inhibited cell apoptosis of SNU-5 cells. Furthermore, we found that SOX4 may act as a downstream mediator of BG981369, suggesting that BG981369 inhibits proliferation, migration, and invasion, and promotes apoptosis by targeting SOX4 in the GC cell lines.

Conclusions

Our results suggest that BG981369 and SOX4 are potentially effective therapeutic targets for GC.

LncRNA EWSAT1 promotes ovarian cancer progression through targeting miR-330-5p expression

Ovarian cancer ranks as the fifth common tumour in women and is the leading cause of cancer-related death among the women. Long non-coding RNAs (lncRNAs) play crucial roles in the development of tumors. However, the expression and the role of EWSAT1 in ovarian tumor are still unknown. In our study, we found the expression of EWSAT1 was upregulated in ovarian cancer cell lines and samples. Ecoptic expression of EWSAT1 suppressed miR-330-5p expression in ovarian cancer cell. In addition, the expression of miR-330-5p was downregulated in ovarian cancer cell lines and samples. Moreover, the expression of miR-330-5p was negatively related with the expression of EWSAT1 in ovarian cancer samples. Furthermore, we identified Pdia3 was a direct target gene of miR-330-5p. Ecoptic expression of miR-330-5p suppressed Pdia3 expression and overexpression of EWSAT1 promoted Pdia3 expression in ovarian cancer cell. In addition, Ecoptic expression of miR-330-5p promoted ovarian cancer cell proliferation, colony formation and invasion. Overexpression of EWSAT1 increased ovarian cancer cell proliferation, colony formation and invasion through targeting miR-330-5p. These data suggested that EWSAT1 might act as an oncogene in the development of ovarian cancer partly through inhibiting miR-330-5p expression.

Potential applications of MEG3 in cancer diagnosis and prognosis

LncRNAs are emerging as integral functional and regulatory components of normal biological activities and are now considered as critically involved in the development of different diseases including cancer. In this review, we summarized recent findings on maternally expressed gene 3 (MEG3), a noncoding lncRNA, locates in the imprinted DLK1–MEG3 locus on human chromosome 14q32.3 region. MEG3 is expressed in normal tissues but is either lost or decreased in many human tumors and tumor derived cell lines. Studies have demonstrated that MEG3 is associated with cancer initiation, progression, metastasis and chemo-resistance. MEG3 may affect the activities of TP53, MDM2, GDF15, RB1 and some other key cell cycle regulators. In addition, the level of MEG3 showed good correlation with cancer clinicopathological grade. In summary, MEGs is an RNA-based tumor suppressor and is involved in the etiology, progression, and chemosensitivity of cancers. The alteration of MEG3 levels in various cancers suggested the possibility of using MEG3 level for cancer diagnosis and prognosis.

Long Noncoding RNA and Cancer: A New Paradigm

In addition to mutations or aberrant expression in the protein-coding genes, mutations and misregulation of noncoding RNAs, in particular long noncoding RNAs (lncRNA), appear to play major roles in cancer. Genome-wide association studies of tumor samples have identified a large number of lncRNAs associated with various types of cancer. Alterations in lncRNA expression and their mutations promote tumorigenesis and metastasis. LncRNAs may exhibit tumor-suppressive and -promoting (oncogenic) functions. Because of their genome-wide expression patterns in a variety of tissues and their tissue-specific expression characteristics, lncRNAs hold strong promise as novel biomarkers and therapeutic targets for cancer. In this article, we have reviewed the emerging functions and association of lncRNAs in different types of cancer and discussed their potential implications in cancer diagnosis and therapy. Cancer Res; 77(15); 3965-81. ©2017 AACR.

Knockdown of long non-coding RNA HOXD-AS1 inhibits gastric cancer cell growth via inactivating the JAK2/STAT3 pathway

Long non-coding RNA HOXD-AS1 (HOXD cluster antisense RNA 1) has been demonstrated to be closely associated with the progression of several tumors. However, the biological function of HOXD-AS1 and the underlying molecular mechanism in gastric cancer are still unclear. The expression of HOXD-AS1 in gastric cancer cell lines was evaluated by quantitative real-time polymerase chain reaction. The association of HOXD-AS1 expression and clinical parameters was statistically analyzed by chi-square test. Cell viability, colony formation capacity, and phosphorylation of Janus kinase 2 and signal transducer and activator of transcription 3 in treated SGC-7901 and BGC-823 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, and western blot analysis, respectively. The results indicated that HOXD-AS1 was significantly upregulated in gastric cancer cells and clinically involved in tumor size, invasion depth, tumor-node-metastasis stages, regional lymph nodes, lymphatic metastasis, as well as distant metastasis. HOXD-AS1 knockdown dramatically inhibited gastric cancer cell proliferation, colony formation capacity, and phosphorylation of Janus kinase 2 and signal transducer and activator of transcription 3 in vitro. In addition, HOXD-AS1 overexpression significantly promoted gastric cancer cell proliferation and colony formation capacity, whereas both Janus kinase small interfering RNAs and Janus kinase 2 inhibitor AG490 overturned these effects. Furthermore, xenograft assays confirmed the biological function of HOXD-AS1 in vivo. Taken together, our data elucidate that knockdown of HOXD-AS1 dramatically suppresses gastric cancer cell growth by inactivating the Janus kinase 2/signal transducer and activator of transcription 3 pathway in vitro and in vivo, contributing to a better understanding of gastric cancer pathogenesis and providing a possible theoretical foundation for long non-coding RNA-directed diagnosis and therapy against this disease.

Following MicroRNAs Through the Cancer Metastatic Cascade

Approximately a decade ago the first MicroRNAs (MiRNAs) participating in cancer metastasis were identified and metastmiRs were initially only a handful. Since those first reports, MiRNA research has explosively thrived, mainly due to their revolutionary mechanism of action and the hope of having at hand a novel tool to control cancer aggressiveness. This has ultimately led to delineate an almost impenetrable regulatory network: hundreds of MiRNAs transversally dominating every aspect of normal and cancer biology, each MiRNA having hundreds of targets and context-dependent activity. Providing a comprehensive description of MiRNA roles in cancer metastasis is a daunting task; nevertheless, we still believe that grasping the big picture of MiRNAs in cancer metastasis can give a different perspective on the potential insights and approaches that MiRNAs can offer to understand cancer complexity (e.g., as predictive and prognostic markers) and to tackle cancer metastasis (e.g., as therapeutic targets or tools). This chapter presents a schematic overview of the role of MiRNAs in governing cancer metastasis, describing step by step the cellular and molecular processes whereby cancer cells conquer distant organs and can grow as secondary tumors at different distant sites, and for each step, we will introduce how MiRNAs impinge on each one of them. We deeply apologize with our colleagues for any of their research work that, for clarity, for our effort to streamline and due to space limitations, we did not cite.

Transcriptome analysis of miRNA-lncRNA-mRNA interactions in the malignant transformation process of gastric cancer initiation

Gastric cancer is a common heterogeneous malignancy that is pathologically characterized by the development of chronic atrophic gastritis and dysplasia of the epithelium. The pathogenic mechanisms at the molecular level are completely unclear. In the present study, we first address the expression network and miRNA-lncRNA-mRNA interaction in the malignant transformation process from normal mucosa and atrophic gastritis to a tumor. First, the long non-coding RNA (lncRNA), micro RNA (miRNA) and messenger RNA (mRNA) expression profiles of normal gastric mucosa, atrophic gastritis, gastric cancer and the peri-tumor tissues were analyzed using microarrays. Then, bioinformatic analyses were used to predict the gene targets and analyse their potential roles in tumorigenesis and progression of gastric cancer. Finally, an intersection analysis of microarray data showed that 10 miRNAs and 11 lncRNAs were detected in the malignant transformation process from normal mucosa tissues and atrophic gastritis to tumorigenesis, and many miRNAs and lncRNAs were novel and had important roles. Meanwhile, the significant pathways and biological functions regulated by the deregulated 21 non-coding genes were enriched. In conclusion, our work provides an important theoretical, experimental and clinical foundation for further research on more effective targets for the diagnosis, therapy and prognosis of gastric cancer.

miR-181a modulates proliferation, migration and autophagy in AGS gastric cancer cells and downregulates MTMR3

MicroRNAs (miRs) have emerged as crucial regulators of tumorigenesis by regulating post-transcriptional gene expression. miR-181a was previously demonstrated to be overexpressed in human gastric cancer tissues and cell lines, whereas MTMR3 was underexpressed. The MTMR3 gene was identified as a direct target of miR-181a. However, its functional role in gastric cancer remains to be established. In the present study, miR-181a was demonstrated to inhibit MTMR3 expression in AGS cells. Ectopic expression of miR-181a mimics or introduction of MTMR3 small interfering RNA resulted in an increase in cell proliferation, colony formation, migration, invasion, as well as suppression of apoptosis. Further investigation in the present study indicated that overexpression of miR-181a, or depletion of MTMR3, attenuated starvation-induced autophagy in AGS cells. In addition, inhibition of endogenous miR-181a led to stimulation of autophagic activity. Collectively, these data suggest that miR-181a is a novel regulator of gastric cancer progression and autophagy, and miR-181a modulation may be a potential strategy for the development of miRNA-based therapeutics for gastric cancer.

miR-101-3p Suppresses HOX Transcript Antisense RNA (HOTAIR)-Induced Proliferation and Invasion Through Directly Targeting SRF in Gastric Carcinoma Cells

miR-101-3p has been identified as a tumor suppressor in several cancers, but its exact role in gastric adenocarcinoma is still largely unknown. In this study, we found that, compared with the RGM-1 human normal gastric epithelial cells, miR-101-3p was significantly downregulated in all six human gastric adenocarcinoma cell lines, including BGC-823, MNK-45, MGC-803, SGC-7901, AGS, and HGC-27. Overexpression of miR-101-3p suppressed both the proliferation and invasion of AGS gastric adenocarcinoma cells, and knockdown of miR-101-3p displayed the opposite effect. In addition, miR-101-3p could directly target and suppress the expression of the serum response factor (SRF) gene, which is a transcription factor of HOTAIR, a well-characterized tumor promoter lncRNA. miR-101-3p negatively regulated SRF-mediated transcription of HOTAIR. Moreover, silencing of either SRF or HOTAIR could counteract the promotion of gastric adenocarcinoma cell proliferation and invasion by miR-101-3p inhibition. Our findings indicate that miR-101-3p suppresses HOTAIR-induced proliferation and invasion through directly targeting SRF in gastric carcinoma cells.

Nuclear Drosha enhances cell invasion via an EGFR-ERK1/2-MMP7 signaling pathway induced by dysregulated miRNA-622/197 and their targets LAMC2 and CD82 in gastric cancer

Drosha is an RNA III-like enzyme that has an aberrant expression in some tumors. Our previous studies showed the aberrant Drosha in gastric tumors. However, the roles of nuclear Drosha, the main regulator of microRNA (miRNA) biogenesis, in gastric cancer (GC) progression remain poorly understood. In this study, we demonstrated that nuclear Drosha is significantly associated with cell invasion of GC and that Drosha silence impedes the tumor invasion. Knockdown of Drosha led to a set of dysregulated miRNAs in GC cells. Multiple targets of these miRNAs were the members in cell migration, invasion and metastasis-associated signaling (e.g. ECM-receptor interaction, focal adhesion, p53 signaling and MAPK signaling pathway) revealed by bioinformatics analysis. LAMC2 (a key element of ECM-receptor signaling) and CD82 (a suppressor of p53 signaling) are the targets of miR-622 and miR-197, respectively. High levels of LAMC2 and low levels of CD82 were significantly related to the worse outcome for GC patients. Furthermore, overexpression of LAMC2 and knockdown of CD82 markedly promoted GC cell invasion and activated EGFR/ERK1/2-MMP7 signaling via upregulation of the expression of phosphorylated (p)-EGFR, p-ERK1/2 and MMP7. Our findings suggest that nuclear Drosha potentially has a role in the development of GC.

Molecular mechanisms of long noncoding RNAs on gastric cancer

Long noncoding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides. Aberrant expression of lncRNAs has been found associated with gastric cancer, one of the most malignant tumors. By complementary base pairing with mRNAs or forming complexes with RNA binding proteins (RBPs), some lncRNAs including GHET1, MALAT1, and TINCR may mediate mRNA stability and splicing. Other lncRNAs, such as BC032469, GAPLINC, and HOTAIR, participate in the competing endogenous RNA (ceRNA) network. Under certain circumstances, ANRIL, GACAT3, H19, MEG3, and TUSC7 exhibit their biological roles by associating with microRNAs (miRNAs). By recruiting histone-modifying complexes, ANRIL, FENDRR, H19, HOTAIR, MALAT1, and PVT1 may inhibit the transcription of target genes in cis or trans. Through these mechanisms, lncRNAs form RNA-dsDNA triplex. CCAT1, GAPLINC, GAS5, H19, MEG3, and TUSC7 play oncogenic or tumor suppressor roles by correlated with tumor suppressor P53 or onco-protein c-Myc, respectively. In conclusion, interaction with DNA, RNA and proteins is involved in lncRNAs' participation in gastric tumorigenesis and development.

MiR-330-3p inhibits gastric cancer progression through targeting MSI1

Increasing evidences demonstrated that microRNAs (miRNAs) play critical roles in the human tumor development and progression. In our study, we found that miR-330-3p expression was downregulated in gastric cancer cell lines and tissues. Ectopic expression of miR-330-3p suppressed the gastric cancer cell proliferation, colony formation and migration. Overexpression of miR-330-3p promoted E-cadherin expression and inhibited the expression of N-cadherin, vimentin and snail. We identified Musashi-1 (MSI1) as a direct target gene of miR-330-3p in gastric cancer cell. In addition, MSI1 was upregulated in gastric cancer cell lines and tissues and the MSI1 expression was inversely correlated with miR-330-3p expression in gastric cancer tissues. MiR-330-3p expression was increased in gastric cancer cells after treated with histone deacetylase inhibitor trichostatin A (TSA) and DNA methylation inhibitor 5-aza-CdR (AZA). These indicated that downregulated expression of miR-330-3p was partly mediated by gene promoter region hypermethylation. These results suggested that miR-330-3p acted as a tumor suppressor gene in GC.

Berberine modulates cisplatin sensitivity of human gastric cancer cells by upregulation of miR-203

Chemotherapeutic resistance is the main reason of the failure in clinical treatment of gastric cancer. Berberine (BER) is the active compound of traditional Chinese medicine Huang Lian. The aim of this present study is to evaluate the effect of BER on cisplatin resistance in gastric cancer cells and to investigate its possible mechanism. Gastric cancer cell lines SGC-7901 and BGC-823 and their respective cisplatin-resistant variants SGC-7901/DDP and BGC-823/DDP were used in this study. We found that BER treatment significantly reversed cisplatin sensitivity and induced caspase-dependent apoptosis in SGC-7901/DDP and BGC-823/DDP cells; BER treatment induced miR-203 expression, and overexpression of miR-203 mimicked the cisplatin-sensitizing effect of BER. Importantly, we showed that miR-203 was able to target the 3'UTR of Bcl-w. Therefore, we conclude that BER treatment reduces cisplatin resistance of gastric cancer cells by modulating the miR-203/Bcl-w apoptotic axis. BER may be a novel agent to enhance chemotherapeutic responses in cisplatin-resistant gastric cancer patients.

CCAT1: a pivotal oncogenic long non-coding RNA in human cancers

Long non-coding RNAs (lncRNAs) compose a group of non-protein-coding RNAs - more than 200 nucleotides in length. Recent studies have shown that lncRNAs play important roles in different cellular processes, including proliferation, differentiation, migration and invasion. Deregulation of lncRNAs has been widely reported in human tumours, in which they are able to function as either oncogenes (on the one hand) or tumour suppressor genes (on the other). Deregulation of CCAT1 (colon cancer-associated transcript-1), an oncogenic lncRNA, has been documented in different types of malignancy, such as gastric cancer, colorectal cancer and hepatocellular carcinoma. In this regard, enforced expression of CCAT1 exerts potent tumorigenic effects by promoting cell proliferation, invasion and migration. Recent evidence has also shown that CCAT1 may serve as a prognostic cancer biomarker. In this review, we provide an overview of current evidence relating to the role and biological function of CCAT1 in tumour development.

Expression of ANRIL-Polycomb Complexes-CDKN2A/B/ARF Genes in Breast Tumors: Identification of a Two-Gene (EZH2/CBX7) Signature with Independent Prognostic Value

ANRIL, a long noncoding RNA (lncRNA), has recently been reported to have a direct role in recruiting polycomb repressive complexes PRC2 and PRC1 to regulate the expression of the p15/CDKN2B-p16/CDKN2A-p14/ARF gene cluster. Expression analysis of ANRIL, EZH2, SUZ12, EED, JARID2, CBX7, BMI1, p16, p15, and p14/ARF genes was evaluated in a large cohort of invasive breast carcinomas (IBC, n = 456) by qRT-PCR and immunohistochemistry (IHC) was performed on CBX7, EZH2, p14, p15, p16, H3K27me3, and H3K27ac. We observed significant overexpression in IBCs of ANRIL (19.7%) and EZH2 (77.0%) and an underexpression of CBX7 (39.7%). Correlations were identified between these genes, their expression patterns, and several classical clinical and pathologic parameters, molecular subtypes, and patient outcomes, as well as with proliferation, epithelial-mesenchymal transition, and breast cancer stem cell markers. Multivariate analysis revealed that combined EZH2/CBX7 status is an independent prognostic factor (P = 0.001). In addition, several miRNAs negatively associated with CBX7 underexpression and EZH2 overexpression. These data demonstrate a complex pattern of interactions between lncRNA ANRIL, several miRNAs, PRC2/PRC1 subunits, and p15/CDKN2B-p16/CDKN2A-p14/ARF locus and suggest that their expression should be considered together to evaluate antitumoral drugs, in particular the BET bromodomain inhibitors.

IMPLICATIONS

This study suggests that the global pattern of expression rather than expression of individual family members should be taken into account when defining functionality of repressive Polycomb complexes and therapeutic targeting potential. Mol Cancer Res; 14(7); 623-33. ©2016 AACR.

miR-448 suppressed gastric cancer proliferation and invasion by regulating ADAM10

MicroRNAs (miRNAs) are a class of short, noncoding RNAs that act a crucial role in tumor development. Previous studies showed that miR-448 expression was deregulated in many tumors. However, the role of miR-448 in gastric cancer (GC) remains unknown. In our study, we demonstrated that miR-448 expression was downregulated in GC tissues compared with the corresponding nontumor tissues. We also showed that miR-448 expression was downregulated in GC cell lines. Ectopic expression of miR-448 suppressed GC cell proliferation, colony formation, and invasion. Moreover, we identified A Disintegrin And Metalloproteinases 10 (ADAM10) as a direct target gene of miR-448 in GC cell. ADAM10 expression was upregulated in GC tissues and cells. Furthermore, the expression level of miR-448 was negatively correlated with the expression level of ADAM10 in GC tissues. Moreover, ADAM10 overexpression rescued the effect of miR-448-mediated GC cell proliferation, colony formation, and invasion. These results demonstrated that miR-448 might play as a tumor suppressor miRNA partly through targeting ADAM10 expression.

The effect of antisense inhibitor of miRNA 106b∼25 on the proliferation, invasion, migration, and apoptosis of gastric cancer cell

Accumulating data has demonstrated that miRNA 106b∼25, which are composed of the highly conserved miRNA 106b, miRNA 93, and miRNA 25, play carcinogenic roles in cancers. We investigated the expression of miRNA 106b∼25 in gastric cancer cells (SGC 7901, MGC 803, BGC 823) and normal gastric epithelial cell then inhibited miRNA 106b∼25 expression via transiently transfecting their antisense inhibitor. After miRNA 106b∼25 cluster was inhibited, MTT, Scratch test, Transwell invasion test, and flow cytometry were applied to investigate the proliferation, invasion, migration, cell cycle, and apoptosis of gastric cancer cell. The expression of miRNA 106b, miRNA 93, and miRNA 25 in gastric cancer cells SGC 7901, MGC 803, and BGC 823 was significantly higher than in gastric epithelial cell GES-1. The most significant suppression of miRNA 106b∼25 expressions can be detected in MGC 803 cell after transiently transfecting their antisense inhibitors. So, MGC 803 cell was selected as our research object. After inhibiting miRNA 106b and miRNA 93 respectively and combined, the proliferation, migration, and invasion of gastric cancer cell MGC 803 were significantly suppressed. The most significant suppression was observed in combined inhibiting group. After miRNA 106b∼25 cluster was inhibited respectively or combined, more gastric cancer cells were arrested in the G0G1 phase. However, there was no statistical difference in comparing with control groups. While the percentages of apoptotic cells increased after miRNA 106b∼25 cluster was inhibited, the statistical difference was detected only in combined inhibiting group. Inhibiting miRNA 106b∼25 cluster via transfecting antisense inhibitor can influence biological behavior of gastric cancer cell.

ANRIL: a pivotal tumor suppressor long non-coding RNA in human cancers

Long non-coding RNAs (lncRNAs) are a family of non-protein-coding RNAs with length more than 200 nucleotides. LncRNAs played important roles in many biological processes such as cell development, proliferation, invasion and migration. Deregulation of LncRNAs was found in multiple tumors where they can act as a tumor suppressor gene or oncogene. LncRNA ANRIL was identified as an oncogene involved in a number of tumors such as gastric cancer, lung cancer, hepatocellular carcinoma, and esophageal squamous cell carcinoma. Inhibition of ANRIL suppressed the cancer cell proliferation, migration and invasion. Increasing data has showed that ANRIL may act as a diagnostic and prognostic biomarker for some tumors. In our review, we summarize an overview of current knowledge concerning the expression and role of ANRIL in various cancers.

Comparison of Prognostic MicroRNA Biomarkers in Blood and Tissues for Gastric Cancer

Gastric cancer (GC) still keeps up high mortality worldwide with poor prognosis. Efficient and non-invasive prognostic biomarkers are urgently needed. MicroRNAs are non-coding RNAs playing roles in post-transcriptional gene regulation, which contribute to various biological processes such as development, differentiation and carcinogenesis. MicroRNA expression profiles have been associated with the prognosis and outcome in GC. MicroRNA prognostic biomarkers have been identified from blood or tissues samples, but with different prognostic features. Understanding the various roles of microRNAs in different sample sources of GC will provide deep insights into GC progression. In this review, we highlight the distinct prognostic roles of microRNAs biomarkers in blood and tissue according to their relationships with prognostic parameters, survival rates and target pathways. This will be useful for non-invasive biomarker development and selection in prognosis of GC.

miR-449a targets Flot2 and inhibits gastric cancer invasion by inhibiting TGF-β-mediated EMT

BACKGROUND

Flot2, a highly conserved protein of the SPFH domain containing proteins family, has recently been identified as oncogene to be involved in the tumorigenesis and metastasis of several cancers including gastric cancer. However, the underlying molecular mechanism of Flot2 in gastric cancer (GC) is largely unknown.

METHODS

qRT-PCR and western blot was performed to detect miR-449a and Flot2 expression in GC cell lines and Normal human gastric epithelial cells. Then, luciferase reporter assay was used to elucidate whether Flot2 is a target gene of miR-449a. Finally, the roles and mechanism of miR-449a in regulation of tumor invasion were further investigated.

RESULTS

In this study, miR-449a expression was downregulated and Flot2 was upregulated in all GC cell lines as compared with that in GES-1. luciferase reporter assay identified Flot2 as a novel direct target of miR-449a. miR-449a regulated GC cell invasion by suppressing Flot2 expression. Expression analysis of a set of epithelial-mesenchymal transition (EMT) markers showed that miR-449a reduced the expression of mesenchymal markers (vimentin and N-cadherin) and induced the expression of epithelial marker (E-cadherin), which was consistent with silenced Flot2. Moreover, Flot2 is necessary for TGF-β-induced EMT in GC cells.

CONCLUSIONS

Our results demonstrated that miR-449a suppressed Flot2 expression results in decreased cell invasion through repressing TGF-β-mediated-EMT, and provides a new theoretical basis to further investigate miR-449a-regulated Flot2 as a potential biomarker and a promising approach for GC treatment.

SATB2 suppresses gastric cancer cell proliferation and migration

Gastric cancer is one of the death-related malignant tumors worldwide. It remains a challenge for the diagnosis and treatment of gastric cancer. Special AT-rich sequence-binding protein 2 (SATB2) is a new tumor suppressive gene and plays important roles in many cancers. However, the role of SATB2 in gastric cancer is still unknown. In the present study, we demonstrated that downregulation of SATB2 was associated with shortened survival in patients with gastric cancer. Ectopic expression of SATB2 inhibited gastric cancer cell proliferation, colony formation, and migration. Overexpression of SATB2 repressed the expression of extracellular signal-regulated kinase 5 (ERK5), and activation of ERK5 restored the SATB2-induced inhibition of proliferation and migration in gastric cancer. This study provided evidence that SATB2 acted as a tumor suppressive gene gastric cancer, serving as a potential therapeutic target.

Dysregulation of non-coding RNAs in gastric cancer

Gastric cancer (GC) is one of the most common cancers in the world and a significant threat to the health of patients, especially those from China and Japan. The prognosis for patients with late stage GC receiving the standard of care treatment, including surgery, chemotherapy and radiotherapy, remains poor. Developing novel treatment strategies, identifying new molecules for targeted therapy, and devising screening techniques to detect this cancer in its early stages are needed for GC patients. The discovery of non-coding RNAs (ncRNAs), primarily microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), helped to elucidate the mechanisms of tumorigenesis, diagnosis and treatment of GC. Recently, significant research has been conducted on non-coding RNAs and how the regulatory dysfunction of these RNAs impacts the tumorigenesis of GC. In this study, we review papers published in the last five years concerning the dysregulation of non-coding RNAs, especially miRNAs and lncRNAs, in GC. We summarize instances of aberrant expression of the ncRNAs in GC and their effect on survival-related events, including cell cycle regulation, AKT signaling, apoptosis and drug resistance. Additionally, we evaluate how ncRNA dysregulation affects the metastatic process, including the epithelial-mesenchymal transition, stem cells, transcription factor activity, and oncogene and tumor suppressor expression. Lastly, we determine how ncRNAs affect angiogenesis in the microenvironment of GC. We further discuss the use of ncRNAs as potential biomarkers for use in clinical screening, early diagnosis and prognosis of GC. At present, no ideal ncRNAs have been identified as targets for the treatment of GC.

MiR-498 regulated FOXO3 expression and inhibited the proliferation of human ovarian cancer cells

Ovarian cancer is one of the most common human malignancies and the fifth leading cause of cancer deaths in women. Thus, improved approaches for detection of ovarian cancer are urgently needed. Recently, microRNAs (miRNAs) have been suggested to be closely associated with ovarian cancer tumorigenesis. In the current study, our study showed that expression of miR-498 was markedly downregulated in ovarian cancer cells and ovarian cancer tissues compared with human ovary surface epithelial cells (HOSE) and the matched tumor adjacent normal tissues (ANT). Ectopic expression of miR-498 suppressed cell proliferation of ovarian cancer cells, while i miR-498-in showed the opposite effect. Furthermore, upregulation of miR-498 in ovarian cancer cells resulted in blocking of their entry into the S transitional phase, which was caused by downregulation of the CDK regulator cyclin D1 and upregulation of cyclin-dependent kinase inhibitor p27. Additionally, we identified FOXO3 as a direct target of miR-498. Moreover, we demonstrated that miR-498 upregulated FOXO3 expression by directly targeting the FOXO3 3'-untranslated region. Thus, our findings suggested that miR-498 acted as a new tumor suppressor by targeting the FOXO3 gene and inhibiting cell proliferation of ovarian cancer.