Dysregulated lncRNA-UCA1 contributes to the progression of gastric cancer through regulation of the PI3K-Akt-mTOR signaling pathway

The effect of LNCRNA SHANK3 on the malignant development of gastric cancer cells by regulating the miR-4530/MNX1

Gastric cancer (GC) has become the first malignant tumor with highest incidence rate and mortality of cancer in China, finding therapeutic targets for gastric cancer is of great significant for improving the survival rate of patients with GC. Recently, many of studies have shown that LncRNAs is involved in multiple biological progresses in the development of GC. This study, we screened for abnormally high expression of LncSHANK3 in GC through the TCGA database, and found that LncSHANK3 sponge adsorbs miR-4530, further competing with MNX1 and binding to miR-4530. We demonstrated the interaction between LncSHANK3 and miR-4530 through luciferase reporting analysis, with miR-4530 negatively regulating MNX1.Through CCK8, colony formation, transwell, and wound healing assays, it was found that LncSHANK3 affects the occurrence of GC through cell proliferation, migration and invasion. In conclusion, LncSHANK3/miR-4530/MNX1 axis is a potential mechanism for the treatment of GC.

POLR1D silencing suppresses lung cancer cells proliferation and migration via inhibition of PI3K-Akt pathway

AIM

The most common type of cancer that leads to death worldwide is lung cancer. Despite significant surgery and chemotherapy improvements, lung cancer patient's survival rate is still poor. The RNA polymerase I subunit D (POLR1D) gene can induce various cancers. A current study reported that POLR1D plays a vital role in cancer prognosis. However, its biological function in the development of lung cancer remains unclear.

METHODS

Reverse transcription PCR (RT-PCR) measured the relative POLR1D protein expression level in lung cancer cell lines. Lung cancer cell proliferation, migration, and invasion were analyzed by performing cell counting kit-8 (CCK-8), and transwell. The phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/AKT) signaling pathway-related protein expressions were examined by Western blotting assay.

RESULTS

POLR1D protein expression was elevated in lung cancer. Lung cancer cell loss-of-function tests showed that POLR1D silencing could attenuate cell viability both in SK-MES-1 and in H2170 cells. Furthermore, silencing POLR1D inhibited SK-MES-1 and H2170 cells proliferation, migration, and invasion. Moreover, SK-MES-1 and H2170 cells' migration and invasion capacity were potentially suppressed by the knockdown of POLR1D. The progression of multiple cancers has been implicated in the PI3K/AKT pathway. Here, we observed that POLR1D silencing suppressed lung cancer progression by inhibition of the PI3K-Akt pathway.

CONCLUSIONS

The study speculated that POLR1D might provide a new potential therapeutic possibility for treating lung cancer patients via targeting PI3K/AKT.

Curcumin inhibits the growth and invasion of gastric cancer by regulating long noncoding RNA AC022424.2

BACKGROUND

Gastric cancer, characterized by a multifactorial etiology and high heterogeneity, continues to confound researchers in terms of its pathogenesis. Curcumin, a natural anticancer agent, exhibits therapeutic promise in gastric cancer. Its effects include promoting cell apoptosis, curtailing tumor angiogenesis, and enhancing sensitivity to radiation and chemotherapy. Long noncoding RNAs (lncRNAs) have garnered significant attention as biomarkers for early screening, diagnosis, treatment, and drug response because of their remarkable specificity and sensitivity. Recent investigations have revealed an association between aberrant lncRNA expression and early diagnosis, clinical staging, metastasis, drug sensitivity, and prognosis in gastric cancer. A profound understanding of the intricate mechanisms through which lncRNAs influence gastric cancer development can provide novel insights for precision treatment and tailored management of patients with gastric cancer. This study aimed to unravel the potential of curcumin in suppressing the malignant behavior of gastric cancer cells by upregulating specific lncRNAs and modulating gastric cancer onset and progression.

AIM

To identify lncRNAs associated with curcumin treatment and investigate the role of lncRNA AC022424.2 in the effects of curcumin on gastric cancer cell apoptosis, proliferation, and invasion. Furthermore, these findings were validated in clinical samples.

METHODS

The study employed CCK-8 assays to assess the impact of curcumin on gastric cancer cell proliferation, flow cytometry to investigate its effects on apoptosis, and scratch and Transwell assays to evaluate its influence on the migration and invasion of BGC-823 and MGC-803 cells. Western blotting was used to gauge changes in the protein expression levels of CDK6, CDK4, Bax, Bcl-2, caspase-3, P65, and the PI3K/Akt/mTOR pathway in gastric cancer cell lines after curcumin treatment. Differential expression of lncRNAs before and after curcumin treatment was assessed using lncRNA sequencing and validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in BGC-823 and MGC-803 cells. AC022424.2-1 knockdown BGC-823 and MGC-803 cells were generated to scrutinize the impact of lncRNA AC022424.2 on apoptosis, proliferation, migration, and invasion of gastric cancer cells. Western blotting was performed to ascertain changes in the expression of proteins implicated in the PI3K/Akt/mTOR and NF-κB signaling pathways. RT-PCR was employed to measure lncRNA AC022424.2 expression in clinical gastric cancer tissues and to correlate its expression with clinical pathological characteristics.

RESULTS

Curcumin induced apoptosis and hindered proliferation, migration, and invasion of gastric cancer cells in a dose- and time-dependent manner. LncRNA AC022424.2 was upregulated after curcumin treatment, and its knockdown enhanced cancer cell aggressiveness. LncRNA AC022424.2 may have affected cancer cells via the PI3K/Akt/mTOR and NF-κB signaling pathways. LncRNA AC022424.2 downregulation was correlated with lymph node metastasis, making it a potential diagnostic and prognostic marker.

CONCLUSION

Curcumin has potential anticancer effects on gastric cancer cells by regulating lncRNA AC022424.2. This lncRNA plays a significant role in cancer cell behavior and may have clinical implications in diagnosis and prognosis evaluation. The results of this study enhance our understanding of gastric cancer development and precision treatment.

Long intergenic non-protein coding RNA 115 (Linc00115): A notable oncogene in human malignancies

Long noncoding RNAs (LncRNAs) are RNA transcripts ranging from 200 to 1000 nucleotides that have emerged as critical regulators of gene expression. Growing evidence highlights their involvement in tumor development. In particular, long intergenic non-protein coding RNA115 (Linc00115) has been identified as an oncogene across various human malignancies, with aberrant expression strongly linked to poor clinical outcomes in cancer patients. This review aims to delve into the expression patterns of Linc00115 and elucidate the underlying molecular mechanisms behind its oncogenic properties. Moreover, we discuss the potential utility of Linc00115 as a valuable diagnostic and prognostic biomarker in cancer.

Recent progress and the emerging role of lncRNAs in cancer drug resistance; focusing on signaling pathways

It is becoming more and more apparent that many of the genetic alterations associated with cancer are located in areas that do not encode proteins. lncRNAs are a class of RNAs that do not code for proteins but play a crucial role in maintaining cell function and regulating various cellular processes. By doing this, they have recently introduced what may be a brand-new and essential layer of biological control. These have more than 200 nucleotides and are linked to several diseases; as a result, they have become potential tools for therapeutic intervention. Emerging technologies suggest the presence of mutations on genomic loci that give rise to lncRNAs rather than proteins in a disease as complex as cancer. These lncRNAs play essential parts in gene regulation, which impacts several cellular homeostasis processes, including proliferation, survival, migration, and genomic stability. The leading cause of death in the world today is cancer. Delays in diagnosis and a lack of standard and efficient treatments are the leading causes of the high death rate. Clinically, surgery is frequently used successfully to remove cancers that have not spread, but it is less successful in treating metastatic cancer, which has a drastically lower chance of survival. Chemotherapeutic drugs are a typical therapy to treat the cancer that has spread to other organs. Drug resistance to chemotherapy, however, presents a significant challenge to achieving positive outcomes and is frequently the cause of treatment failure. A substantial barrier to progress in medical oncology is cancer drug resistance. Resistance can develop clinically either before or after cancer treatment. According to this study, lncRNAs influence drug resistance through several different methods. LncRNAs often impact drug resistance by controlling the expression of a few intermediary regulatory variables rather than by directly affecting drug resistance. Additionally, lncRNAs have a variety of roles in cancer medication resistance. Most lncRNAs induce drug resistance when overexpressed; however, other lncRNAs have inhibitory effects. This study provides an overview of the current understanding of lncRNAs, relevance to cancer, and potential therapeutic applications.

PLAGL2 promotes Snail expression and gastric cancer progression via UCA1/miR-145-5p/YTHDF1 axis

OBJECTIVES

Although great progress has made in gastric cancer (GC) in the past years, the overall 5-year survival rate remains to be low for advanced GC patients. A recent study showed that PLAGL2 was increased in GC and enhanced the proliferation and metastasis of GC. Nevertheless, the underlying mechanism still needs to be investigated.

METHODS

Gene and protein expressions were assessed using RT-qPCR and western blot. The migration, proliferation and invasion of GC cells were examined using scratch assay, CCK-8 assay and Transwell assay, respectively. ChIP-PCR, dual-luciferase assay, RIP-qPCR and CoiP were utilized to confirm the interaction among PLAGL2, UCA1, miR-145-5p and YTHDF1 as well as METTL3, YTHDF1 and eEF-2. A mouse xenograft model was used utilized to further confirm the regulatory network.

RESULTS

PLAGL2 bound to the upstream promoter of UCA1, which regulated YTHDF1 by sponging miR-145-5p. METTL3 can mediate the m6A modification level of Snail. YTHDF1 recognized m6A-modified Snail by interacting with eEF-2 and thus promoted Snail expression, which eventually induced epithelial-mesenchymal transition (EMT) in GC cells and metastasis of GC.

CONCLUSIONS

Overall, our study demonstrates that PLAGL2 enhances Snail expression and GC progression via the UCA1/miR-145-5p/YTHDF1 axis, suggesting that PLAGL2 may become a therapeutic target for GC treatment.

Long Non-Coding RNAs (lncRNAs) as Regulators of the PI3K/AKT/mTOR Pathway in Gastric Carcinoma

Gastric cancer (GC) represents ~10% of the global cancer-related deaths, increasingly affecting the younger population in active stages of life. The high mortality of GC is due to late diagnosis, the presence of metastasis and drug resistance development. Additionally, current clinical markers do not guide the patient management adequately, thereby new and more reliable biomarkers and therapeutic targets are still needed for this disease. RNA-seq technology has allowed the discovery of new types of RNA transcripts including long non-coding RNAs (lncRNAs), which are able to regulate the gene/protein expression of many signaling pathways (e.g., the PI3K/AKT/mTOR pathway) in cancer cells by diverse molecular mechanisms. In addition, these lncRNAs might also be proposed as promising diagnostic or prognostic biomarkers or as potential therapeutic targets in GC. This review describes important topics about some lncRNAs that have been described as regulators of the PI3K/AKT/mTOR signaling pathway, and hence, their potential oncogenic role in the development of this malignancy.

LncRNA-UCA1 regulates lung adenocarcinoma progression through competitive binding to miR-383

The present study aimed to assess the role of the long non-coding RNA-urothelial cancer associated 1 (lncRNA-UCA1)/microRNA (miR)-383/vascular endothelial growth factor A (VEGFA) axis in regulating lung adenocarcinoma physiology through in vivo and in vitro experiments. The expression profile of lncRNA-UCA1 was analyzed by genome-wide analysis from GSE146459. The cell counting Kit-8, colony formation, wound healing and transwell assays were performed to evaluate the effects of lncRNA-UCA1 in vitro. In addition, luciferase reporter assays were performed to confirm the binding site. The expression levels of miR-383 and VEGFA in tumor cells were measured using reverse transcription-quantitative PCR. HCC-78 was also transfected with miR-383 mimics, inhibitors and siRNA-VEGFA before their viability was also assessed. Xenograft models were established in nude mice to investigate the tumor characteristics in vivo. The expression of lncRNA-UCA1 was significantly increased in tumor tissues and cells compared with adjacent tissues or HBE cells. Silencing lncRNA-UCA1 expression in cells resulted in a reduction in lung cancer cell viability. In addition, lncRNA-UCA1 silencing increased the expression of miR-383. Inhibiting miR-383 expression increased HCC-78 proliferation, migration and invasion, whilst reducing their apoptosis. miR-383 was shown to specifically target VEGFA to inhibit its expression at both the protein and mRNA levels. VEGFA knockdown resulted in a reduction in all aforementioned aspects of HCC-78 cell activity. In addition, inhibiting miR-383 expression led to larger tumor sizes in vivo. To conclude, the results of the study suggest that lncRNA-UCA1 can regulate the expression of miR-383 and, in turn, VEGFA.

LncRNA UCA1 accelerates osteosarcoma progression via miR-145 and Wnt/β-catenin pathway

Long non-coding (lnc) urothelial cancer associated 1 (UCA1) has been confirmed to participate in osteosarcoma (OS), but its specific mechanism is still under investigation. The study was designed to reveal the interaction between UCA1 and its downstream effector molecules, so as to determine whether there is any interaction of regulating physiological processes in tumor cells. Here, we studied the signaling cascade involving UCA1, miR-145, and HMGA1. The expression of UCA1 and miR-145 levels was interfered to assess their effects on physiological processes of tumor cells. The relationship between UCA1 and miR-145 as well as between HMGA1 and miR-145 was identified by the dual-luciferase reporter (DLR) assay, and the in vivo effect of UCA1 was estimated in nude mouse xenografts. As a result, a negative association was found between UCA1 and miR-145 in OS cells. Both UCA1 knockout and miR-145 over-expression inhibited malignant progression and induced apoptosis in MG-63 and U2OS cells. UCA1 knockout led to an increase in miR-145 and decreases in HMGA1, p-β-catenin and cyclin D1. In addition, UCA1 upregulation promoted tumor growth in vitro and changed miR-145 and HMGA1 levels in vivo. Moreover, the DLR assay and RNA immunoprecipitation (RIP) showed that UCA1 was likely to regulate HMGA1 levels by sponging miR-145. Overall, the inhibition of UCA1 increases miR-145 levels and decreases HMGA1 levels, thereby exerting an anti-tumor role in OS.

Differential Long Non-Coding RNA Expression Analysis in Chronic Non-Atrophic Gastritis, Gastric Mucosal Intraepithelial Neoplasia, and Gastric Cancer Tissues

Gastric cancer (GC) has a high incidence worldwide, and when detected, the majority of patients have already progressed to advanced stages. Long non-coding RNAs (lncRNAs) have a wide range of biological functions and affect tumor occurrence and development. However, the potential role of lncRNAs in GC diagnosis remains unclear. We selected five high-quality samples from each group of chronic non-atrophic gastritis, gastric mucosal intraepithelial neoplasia, and GC tissues for analysis. RNA-seq was used to screen the differentially expressed lncRNAs, and we identified 666 differentially expressed lncRNAs between the chronic non-atrophic gastritis and GC groups, 13 differentially expressed lncRNAs between the gastric mucosal intraepithelial neoplasia and GC groups, and 507 differentially expressed lncRNAs between the chronic non-atrophic gastritis and gastric mucosal intraepithelial neoplasia groups. We also identified six lncRNAs (lncRNA H19, LINC00895, lnc-SRGAP2C-16, lnc-HLA-C-2, lnc-APOC1-1, and lnc-B3GALT2-1) which not only differentially expressed between the chronic non-atrophic gastritis and GC groups, but also differentially expressed between the gastric mucosal intraepithelial neoplasia and GC groups. Furthermore, RT-qPCR was used to verify the differentially co-expressed lncRNAs. LncSEA was used to conduct a functional analysis of differentially expressed lncRNAs. We also predicted the target mRNAs of the differentially expressed lncRNAs through bioinformatics analysis and analyzed targeting correlations between three differentially co-expressed lncRNAs and mRNAs (lncRNA H19, LINC00895, and lnc-SRGAP2C-16). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were used to explore the functions of target mRNAs of differentially expressed lncRNAs. In conclusion, our study provides a novel perspective on the potential functions of differentially expressed lncRNAs in GC occurrence and development, indicating that the differentially expressed lncRNAs might be new biomarkers for early GC diagnosis.

The Emerging role of EMT-related lncRNAs in therapy resistance and their application as biomarkers

Cancer is the world's second largest cause of death. The most common cancer treatments are surgery, radiation therapy, and chemotherapy. Drug resistance, epithelial-to-mesenchymal transition (EMT), and metastasis are all pressing issues in cancer therapy today. Increasing evidence showed that drug-resistant and EMT are co-related with each other. Indeed, drug-resistant cancer cells possess enhanced EMT and invasive ability. Recent researches have demonstrated lncRNAs (long noncoding RNAs) are noncoding transcripts, which play an important role in the regulation of EMT, metastasis, and drug resistance in different cancers. However, the relationships among lncRNAs, EMT, and drug resistance are still unclear. These effects could be exerted via several signaling pathways such as TGF-β, PI3K-AKT, and Wnt/β-catenin. Identifying the crucial regulatory roles of lncRNAs in these pathways and processes leads to the development of novel targeted therapies. We review the key aspects of lncRNAs associated with EMT and therapy resistance. We focus on the crosstalk between lncRNAs and molecular signaling pathways affecting EMT and drug resistance. Moreover, each of the mentioned lncRNAs could be used as a potential diagnostic, prognostic, and therapeutic biomarker for cancer. Although, there are still many challenges to investigate lncRNAs for clinical applications.

The long non-coding RNA UPAT promotes gastric cancer cell progression via UHRF1

BACKGROUND

LncRNA ubiquitin-like with PHD and RING finger domains 1 (UHRF1) protein associated transcript (UPAT) regulates the progression of many cancers. However, its role in gastric cancer (GC) is less frequently reported.

OBJECTIVE

In the context of the promoting effect of lncRNA on modulating GC progression, detailed insights into the role and underlying mechanism of UPAT in GC are the foothold in this study.

METHODS

Overall survival was calculated. The mRNA expressions of UPAT and UHRF1 were measured by qRT-PCR, and the protein expressions of UHRF1, Cyclin D1 and cleaved caspase-3 were determined by western blot. Cell viability, growth, migration and invasion were assessed by CCK-8, colony formation, wound healing and Transwell assays, respectively. Apoptosis rate and cell cycle were assayed by flow cytometry.

RESULTS

UPAT was overexpressed in GC tissue and cell lines. Decreased UPAT level was associated with higher overall survival. Down-regulation of UPAT diminished cell proliferation, Cyclin D1 expression, and migration and invasion rates, increased apoptosis rate and cleaved caspase-3 expression, and blocked cell cycle in AGS and NCI-N87 cells. UPAT expression in GC was positively correlated with UHRF1 expression. UHRF1 overexpression offset the inhibitory effects of UPAT down-regulation on cell proliferation, migration, invasion and cell cycle, and partially reversed the positive effect of UPAT down-regulation on apoptosis.

CONCLUSION

UPAT might positively regulate the progression of GC via interacting with UHRF1. The UHRF1/UPAT axis revealed in the present study may provide a promising approach to intervene in the progression of GC.

Inhibition of HDACs Suppresses Cell Proliferation and Cell Migration of Gastric Cancer by Regulating E2F5 Targeting BCL2

(1) Background: Gastric cancer (GC) is the most common high death-rate cancer type worldwide, with an enhanced prevalence and increased rate of mortality. Although significant evidence on surgery strategy has been generated for the treatment of GC, conclusions are still uncertain regarding profound metastatic or persevering gastric cancer. Therefore, it is essential to develop novel and effective biomarkers or therapeutic targets for the diagnosis of GC. Histone deacetylations (HDACs) are important epigenetic regulators that control the aberrant transcription of critical genes that are mainly involved in cell proliferation, cell migration, regulation of the cell cycle, and different signal pathways. (2) Methods: Expression analysis of HDACs family members and E2F5 in gastric cancer cell lines was determined by RT-PCR and Western blotting. The cell proliferation was determined through an MTT assay. Cell migration was determined using a wound-healing assay. Flow cytometry experiments were used to determine cell-cycle analysis. The statistical software OriginPro 2015 (OriginLab, Northampton, MA, USA) was used to analyze data. A p value of < 0.05 was regarded as significant. (3) Results: The present study shows that E2F5 expression is upregulated in GC cancer cell lines compared to normal cell lines, and is positively associated with the level of HDACs and BCL2. HDACi and knocking down of E2F5 as tumor suppressors inhibited cell proliferation, migration invasion, and blocked the cell cycle in gastric cancer cells by suppressing BCL2. The results conclude that the anticancer mechanism of HDACi was determined by regulating E2F5 via targeting BCL2. (4) Conclusions: Our results suggest that the HDAC–E2F5–BCL2 signaling axis might be a novel potential biomarker in gastric cancer.

Research updates on the clinical implication of long noncoding RNA in digestive system cancers and chemoresistance

Long noncoding RNAs (lncRNAs) are implicated in various biological processes, such as cell proliferation, differentiation, apoptosis, migration, and invasion. They are also key players in various biological pathways. LncRNA was considered as 'translational noise' before 1980s. It has been reported that lncRNAs are aberrantly expressed in different cancers, either as oncogene or tumor suppressor gene. Therefore, more and more lncRNAs are recognized as potential diagnostic biomarkers and/or therapeutic targets. As competitive endogenous RNA, lncRNAs can interact with microRNA to alter the expression of target genes, which may have extensive clinical implications in cancers, including diagnosis, treatment, prognosis, and chemoresistance. This review comprehensively summarizes the functions and clinical relevance of lncRNAs in digestive system cancers, especially as a potential tool to overcome chemoresistance.

LncRNA UCA1 promotes development of gastric cancer via the miR-145/MYO6 axis

Background

Long noncoding RNA (lncRNA), urothelial carcinoma-associated 1 (UCA1) is aberrantly expressed in multiple cancers and has been verified as an oncogene. However, the underlying mechanism of UCA1 in the development of gastric cancer is not fully understood. In the present study, we aimed to identify how UCA1 promotes gastric cancer development.

Methods

The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data were used to analyze UCA1 and myosin VI (MYO6) expression in gastric cancer. Western blot and quantitative real-time PCR (QPCR) were performed to test the expression level of the UCA1/miR-145/MYO6 axis in gastric cancer cell lines and tissues. The roles of the UCA1/miR-145/MYO6 axis in gastric cancer in vitro and in vivo were investigated by CCK-8 assay, flow cytometry, siRNAs, immunohistochemistry, and a mouse xenograft model. The targeted relationship among UCA1, miR-145, and MYO6 was predicted using LncBase Predicted v.2 and TargetScan online software, and then verified by luciferase activity assay and RNA immunoprecipitation.

Results

UCA1 expression was higher but miR-145 expression was lower in gastric cancer cell lines or tissues, compared to the adjacent normal cell line or normal tissues. Function analysis verified that UCA1 promoted cell proliferation and inhibited cell apoptosis in the gastric cancer cells in vitro and in vivo. Mechanistically, UCA1 could bind directly to miR-145, and MYO6 was found to be a downstream target gene of miR-145. miR-145 mimics or MYO6 siRNAs could partly reverse the effect of UCA1 on gastric cancer cells.

Conclusions

UCA1 accelerated cell proliferation and inhibited cell apoptosis through sponging miR-145 to upregulate MYO6 expression in gastric cancer, indicating that the UCA1/miR-145/MYO6 axis may serve as a potential therapeutic target for gastric cancer.

Chemokine (C-C motif) Ligand 6 Aggravates Hypoxia Reoxygenation-induced Apoptosis in H9c2 Cells Through Enhancing the Expression of Insulin-like Growth Factor 2-Antisense

Chemokine (C-C motif) ligand 6 (CCL6), one of the small cytokines in the CC chemokine family, has been reported to involve in renal ischemia-reperfusion (I/R) injury. However, the role of CCL-6 in myocardial I/R injury is nonelucidated. In this study, we used in vitro H9c2 cell model to investigate the overall contributions of CCL6 to myocardial I/R injury. We found the elevated level of CCL6 from the reanalysis of data set GSE-4105 and in hypoxia-reoxygenation (H/R)-injured H9c2 cells. CCL6 silencing attenuated the cardiomyocyte apoptosis induced by H/R injury, whereas exogenous CCL6 treatment aggravated the apoptosis of H/R-injured H9c2 cells. During CCL6 administration, the expression of numerous long noncoding RNAs was differentially regulated. Quantitative RT-Polymerase chain reaction assay demonstrated that insulin-like growth factor 2 (IGF2)-Antisense (AS) had the highest induction by CCL6 addition. IGF2-AS silencing alleviated the apoptosis of H/R-injured H9c2 cells. Collectively, we have identified a potential mechanism by which high expression of CCL6 contributes to the H/R-induced apoptosis in H9c2 cells through enhancing the expression of IGF2-AS. These findings also give evidence of the feasibility of CCL6 or long noncoding RNA IGF2-AS as a potential target for modulation or therapeutic intervention in myocardial I/R injury.

Long Noncoding RNA UCA1 in Gastrointestinal Cancers: Molecular Regulatory Roles and Patterns, Mechanisms, and Interactions

The rising trend of gastrointestinal (GI) cancer has become a global burden due to its aggressive nature and poor prognosis. Long noncoding RNAs (lncRNAs) have recently been reported to be overexpressed in different GI cancers and may contribute to cancer progression and chemoresistance. They are featured with more than 200 nucleotides, commonly polyadenylated, and lacking an open reading frame. LncRNAs, particularly urothelial carcinoma-associated 1 (UCA1), are oncogenes involved in regulating cancer progression, such as cell proliferation, invasion, migration, and chemoresistance, particularly in GI cancer. This review was aimed to present an updated focus on the molecular regulatory roles and patterns of lncRNA UCA1 in progression and chemoresistance of different GI cancers, as well as deciphering the underlying mechanisms and its interactions with key molecules involved, together with a brief presentation on its diagnostic and prognostic values. The regulatory roles of lncRNA UCA1 are implicated in esophageal cancer, gastric cancer, pancreatic cancer, hepatobiliary cancer, and colorectal cancer, where they shared similar molecular mechanisms in regulating cancer phenotypes and chemoresistance. Comparatively, gastric cancer is the most intensively studied type in GI cancer. LncRNA UCA1 is implicated in biological roles of different GI cancers via interactions with various molecules, particularly microRNAs, and signaling pathways. In conclusion, lncRNA UCA1 is a potential molecular target for GI cancer, which may lead to the development of a novel chemotherapeutic agent. Hence, it also acts as a potential diagnostic and prognostic marker for GI cancer patients.

The Functional Role of Long Non-coding RNA UCA1 in Human Multiple Cancers: a Review Study

In various cancers, high-grade tumor and poor survival rate in patients with upregulated lncRNAs UCA1 have been confirmed. Urothelial carcinoma associated 1 (UCA1) is an oncogenic non-coding RNA with a length of more than 200 nucleotides. The UCA1 regulate critical biological processes that are involved in cancer progression, including cancer cell growth, invasion, migration, metastasis, and angiogenesis. So It should not surprise that UCA1 overexpresses in variety of cancers type, including pancreatic cancer, ovarian cancer, gastric cancer, colorectal cancer, breast cancer, prostate cancer, endometrial cancer, cervical cancer, bladder cancer, adrenal cancer, hypopharyngeal cancer, oral cancer, gallbladder cancer, nasopharyngeal cancer, laryngeal cancer, osteosarcoma, esophageal squamous cell carcinoma, renal cell carcinoma, cholangiocarcinoma, leukemia, glioma, thyroid cancer, medulloblastoma, hepatocellular carcinoma and multiple myeloma. In this article, we review the biological function and regulatory mechanism of UCA1 in several cancers and also, we will discuss the potential of its as cancer biomarker and cancer treatment.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

PI3K/AKT/mTOR signaling in gastric cancer: Epigenetics and beyond

PI3K/AKT/mTOR pathway is one of the most important signaling pathways involved in normal cellular processes. Its aberrant activation modulates autophagy, epithelial-mesenchymal transition, apoptosis, chemoresistance, and metastasis in many human cancers. Emerging evidence demonstrates that some infections as well as epigenetic regulatory mechanisms can control PI3K/AKT/mTOR signaling pathway. In this review, we focused on the role of this pathway in gastric cancer development, prognosis, and metastasis, with an emphasis on epigenetic alterations including DNA methylation, histone modifications, and post-transcriptional modulations through non-coding RNAs fluctuations as well as H. pylori and Epstein-Barr virus infections. Finally, we reviewed different molecular targets and therapeutic agents in clinical trials as a potential strategy for gastric cancer treatment through the PI3K/AKT/mTOR pathway.

Metformin Suppresses the Proliferation and Promotes the Apoptosis of Colon Cancer Cells Through Inhibiting the Expression of Long Noncoding RNA-UCA1

PURPOSE

LncRNA-UCA1 has been proven to facilitate the proliferation and metastasis of colon cancer. Whether metformin inhibits the progression of colon cancer by suppressing lncRNA-UCA1 remains unknown. In this research, we aimed to explore the role of Metformin playing in pathogenesis of colon cancer.

MATERIALS AND METHODS

Using qRT-PCR, we measured the expression of five tumor-promoting lncRNAs in SW480 and SW620 colon cancer cells. Then, we conducted Western blotting and immunohistochemistry to evaluate the effects of MET or UCA1 knockdown or the combined MET+ UCA1 knockdown on the activities of the PI3K/AKT and ERK pathways in vitro and in tumor tissues obtained from tumor-bearing nude mice.

RESULTS

The results from CCK-8 assays showed that MET dose-dependently and time-dependently inhibited the viability of the colon cancer cells in vitro. Flow cytometry revealed that MET promoted the apoptosis of the SW480 and SW620 cells. qRT-PCR showed that lncRNA-UCA1 had the highest expression among the five lncRNAs. Suppressing UCA1 expression by siRNA or shRNA could further enhance the metformin-mediated anticancer effects against colon cancer in vitro and in vivo. Metformin decreased the UCA1 expression and further inhibited the proliferation and promoted the apoptosis of the colon cancer cells, which were associated with inactivation of the PI3K/AKT and ERK signaling pathways in vitro and in the tumor tissues obtained from the mice.

CONCLUSION

These results indicated that metformin has potential anticancer properties and revealed the anticancer mechanisms of metformin against colon cancer via regulating lncRNA-UCA1.

Silencing of Long Non-Coding RNA-HCG18 Inhibits the Tumorigenesis of Gastric Cancer Through Blocking PI3K/Akt Pathway

PURPOSE

Long non-coding RNAs (lncRNAs) play critical regulatory roles in the tumorigenesis of GC. This study aimed to investigate the regulatory effect and mechanism of lncRNA-HCG18 on GC.

METHODS

The expression of lncRNA-HCG18 was detected in GC tissues and cell lines by qRT-PCR. LncRNA-HCG18 was silenced in AGS and MGC803 cells by the transfection of lncRNA-HCG18 siRNA (si-HCG18). MTT, transwell and Annexin V-PI double staining assay were performed to assess the proliferation, migration, invasion and apoptosis of GC cells. The expression of PI3K/Akt pathway-, apoptosis-, and migration-related proteins were detected by Western blot. An activator of PI3K/Akt pathway 740 Y-P was used to activate the PI3K/Akt pathway in AGS cells. A human tumor xenograft model was established in mice to evaluate the effects of si-HCG18 in vivo.

RESULTS

LncRNA-HCG18 was overexpressed in GC tissues and cells. Up-regulation of lncRNA-HCG18 was positively correlated with the stage of tumor node metastasis and invasion depth. Silencing of lncRNA-HCG18 suppressed the proliferation, migration and invasion, and induced the apoptosis of GC cells. Silencing of lncRNA-HCG18 blocked the PI3K/Akt pathway. The intervention of 740Y-P reversed the anti-tumor effect of lncRNA-HCG18 on GC cells. In addition, silencing of lncRNA-HCG18 suppressed the growth of GC xenografts in mice.

CONCLUSION

Silencing of lncRNA-HCG18 inhibited the tumorigenesis of GC through blocking the PI3K/Akt pathway, suggesting a novel therapeutic target for GC.

lncRNA HOXB-AS3 exacerbates proliferation, migration, and invasion of lung cancer via activating the PI3K-AKT pathway

Lung cancer remains the leading cause of cancer-related death all over the world. In spite of the great advances made in surgery and chemotherapy, the prognosis of lung cancer patients is poor. A substantial fraction of long noncoding RNAs (lncRNAs) can regulate various cancers. A recent study has reported that lncRNA HOXB-AS3 plays a critical role in cancers. However, its biological function remains unclear in lung cancer progression. In the current research, we found HOXB-AS3 was obviously elevated in NSCLC tissues and cells. Functional assays showed that inhibition of HOXB-AS3 was able to repress A549 and H1975 cell proliferation, cell colony formation ability and meanwhile, triggered cell apoptosis. Furthermore, the lung cancer cell cycle was mostly blocked in the G1 phase whereas the cell ratio in the S phase was reduced. Also, A549 and H1975 cell migration and invasion capacity were significantly repressed by the loss of HOXB-AS3. The PI3K/AKT pathway has been implicated in the carcinogenesis of multiple cancers. Here, we displayed that inhibition of HOXB-AS3 suppressed lung cancer cell progression via inactivating the PI3K/AKT pathway. Subsequently, in vivo experiments were utilized in our study and it was demonstrated that HOXB-AS3 contributed to lung cancer tumor growth via modulating the PI3K/AKT pathway. Overall, we implied that HOXB-AS3 might provide a new perspective for lung cancer treatment via targeting PI3K/AKT.

LncRNA AC093818.1 accelerates gastric cancer metastasis by epigenetically promoting PDK1 expression

Gastric cancer (GC) is a highly prevalent type of metastatic tumor. The mechanisms underlying GC metastasis are poorly understood. Some long noncoding RNAs (lncRNAs) reportedly play key roles in regulating metastasis of GC. However, the biological roles of five natural antisense lncRNAs (AC093818.1, CTD-2541M15.1, BC047644, RP11-597M12.1, and RP11-40A13.1) in GC metastasis remain unclear. In this study, the expression of these lncRNAs was measured by quantitative reverse transcription-polymerase chain reaction. Migration and invasion were evaluated by wound-healing and the Transwell assay, respectively. Stable cells were injected into the tail veins of nude mice. Sections of collected lung and liver tissues were stained using hematoxylin and eosin. Protein expression was analyzed by western blot. RNA immunoprecipitation (RIP) assay was used to verify whether the STAT3 and SP1 transcription factors bound to AC093818.1 in GC cells. Expression levels of the five lncRNAs, especially AC093818.1, were significantly upregulated in metastatic GC tissues relative to those in nonmetastatic GC tissues. AC093818.1 expression was correlated with invasion, lymphatic metastasis, distal metastasis, and tumor-node-metastasis stage. AC093818.1 expression was highly sensitive and specific in the diagnosis of metastatic or nonmetastatic GC. AC093818.1 overexpression promoted GC migration and invasion in vitro and in vivo. AC093818.1 overexpression increased PDK1, p-AKT1, and p-mTOR expression levels. AC093818.1 silencing decreased these expressions. AC093818.1 bound to transcription factors STAT3 and SP1, and SP1 or STAT3 silencing could alleviated the effect of AC093818.1 overexpression. The data demonstrate that lncRNA AC093818.1 accelerates gastric cancer metastasis by epigenetically promoting PDK1 expression. LncRNA AC093818.1 may be a potential therapeutic target for metastatic GC.

Icariin alleviates hypoxia-induced damage in MC3T3-E1 cells by downregulating TALNEC2

Osteonecrosis is a harmful musculoskeletal disease. We aim to detect the effects of icariin (ICA) in MC3T3-E1 cell. MC3T3-E1 cell was pretreated with ICA and was subjected to hypoxia stimuli. The tumor-associated long noncoding RNA expressed on chromosome 2 (TALNEC2) overexpression or silencing vectors (pTALNEC2 or si-TALNEC2) was utilized for MC3T3-E1 cell transfection. Viability and apoptosis rate were individually tested by cell counting kit-8 and Annexin V-fluorescein isothiocyanate/propidium iodide kit untied with flow cytometry. The alkaline phosphatase activity (ALP) activity was tested through ALP assay. The quantitative reverse transcription PCR or Western blot was performed for elements detection at the RNA or protein level. Hypoxia treatment induced viability inhibition and CyclinD1 reduction, but elevation of p53 and p16. It also promoted apoptosis by increasing apoptotic cells, Bax, and cleaved-poly ADP-ribose polymerase but decreasing Bcl-2. Also, hypoxia stimuli restrained ALP activity, and osteopontin, osteocalcin, and Runt-related transcription factor 2 expression. Those effects caused by hypoxia stimuli were all reversed by ICA. TALNEC2 was downregulated by ICA, whose impacts were subsequently abolished by pTALNEC2. Silencing TALNEC2 displayed similar effects with ICA. But the apoptosis was not affected by si-TALNEC2. ICA blocked ste20-related proline/alanine-rich kinase/c-Jun N-terminal kinase (SPAK/JNK) but triggered phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway in MC3T3-E1 cell by suppressing TALNEC2. ICA relieved hypoxia-stimulated damage by restraining TALNEC2 through blocking SPAK/JNK and triggering PI3K/AKT/mTOR in the MC3T3-E1 cell.

Knockdown of lncRNA TDRG1 Inhibits Tumorigenesis in Endometrial Carcinoma Through the PI3K/AKT/mTOR Pathway

BACKGROUND AND OBJECTIVE

Endometrial carcinoma (EC) is one of the most frequently diagnosed malignancies in females. Dysregulation of lncRNA TDRG1 has been widely documented in several cancers, including EC. However, the mechanism of this lncRNA involving in EC progression remains to be further elucidated.

MATERIALS AND METHODS

The enrichment levels of TDRG1 in EC tissues and cell lines were examined by RT-qPCR. Flow cytometry, cell counting kit-8 (CCK-8), transwell, and Western blot assays were conducted to assess whether TDRG1 knockdown could affect cell cycle arrest, proliferation, migration, invasion, and apoptosis of EC cells. The phosphorylation levels of mTOR, AKT and PI3K that associated with PI3K/Akt/mTOR pathway were determined by Western blot assay.

RESULTS

TDRG1 expression was markedly upregulated in EC tissues and cell lines. Knockdown of TDRG1 significantly induced cell cycle arrest and apoptosis, inhibited cell proliferation, restrained the invasion and migration abilities in EC cells. Moreover, TDRG1 silencing decreased the protein levels of p-AKT, p-PI3K, and p-mTOR of EC cells.

CONCLUSION

Our data underlined the implication of TDRG1 in EC progression, proposing that targeting TDRG1 might be a potential therapeutic avenue in EC.

LncRNAs as potential diagnostic and prognostic biomarkers in gastric cancer: A novel approach to personalized medicine

Gastric cancer is the third leading cause of cancer death with 5-year survival rate of about 30-35%. Since early detection is associated with decreased mortality, identification of novel biomarkers for early diagnosis and proper management of patients with the best response to therapy is urgently needed. Long noncoding RNAs (lncRNAs) due to their high specificity, easy accessibility in a noninvasive manner, as well as their aberrant expression under different pathological and physiological conditions, have received a great attention as potential diagnostic, prognostic, or predictive biomarkers. They may also serve as targets for treating gastric cancer. In this review, we highlighted the role of lncRNAs as tumor suppressors or oncogenes that make them potential biomarkers for the diagnosis and prognosis of gastric cancer. Relatively, lncRNAs such as H19, HOTAIR, UCA1, PVT1, tissue differentiation-inducing nonprotein coding, and LINC00152 could be potential diagnostic and prognostic markers in patients with gastric cancer. Also, the impact of lncRNAs such as ecCEBPA, MLK7-AS1, TUG1, HOXA11-AS, GAPLINC, LEIGC, multidrug resistance-related and upregulated lncRNA, PVT1 on gastric cancer epigenetic and drug resistance as well as their potential as therapeutic targets for personalized medicine was discussed.

Downregulation of lncRNA UCA1 ameliorates the damage of dopaminergic neurons, reduces oxidative stress and inflammation in Parkinson's disease through the inhibition of the PI3K/Akt signaling pathway

This study is conducted to investigate the role of lncRNA urothelial carcinoma-associated 1 (UCA1) in the protection of dopaminergic neurons in Parkinson's disease (PD) through regulating the PI3K/Akt signaling pathway. PD rat model was induced by injection of 6-hydroxydopamine (6-OHDA) to damage the substantia nigra striatum. The successfully modeled PD rats were introduced with siRNA-negative control (NC) or UCA1-siRNA. The expression of UCA1 in neurobehavioral change, neuroinflammatory response and oxidative stress of PD rats were explored. The effect of UCA1 on the PI3K/Akt signaling pathway and downstream proteins IκBα and ERK was also investigated. The rats with PD exhibited aggregated neurobehavioral change, increased neuroinflammatory response and oxidative stress. Down-regulation of UCA1 up-regulated the expression of TH positive cells and DA content, reduced the apoptosis of substantia nigra neurons, the apoptosis of substantia nigra neurons and oxidative stress and improved the neuroinflammatory response in PD rats. Down-regulation of UCA1 inhibited the activation of the PI3K/AKT signaling pathway in substantia nigra of PD rats. Our study suggests that the downregulated lncRNA UCA1 ameliorates the damage of dopaminergic neurons, reduces oxidative stress and inflammation in PD rats through the inhibition of the PI3K/Akt signaling pathway.

UCA1 long non-coding RNA: An update on its roles in malignant behavior of cancers

The lncRNA urothelial carcinoma-associated 1 (UCA1) is a 1.4 kb long transcript which has been firstly recognized in human bladder cancer cell line. Subsequent studies revealed its over-expression in a wide array of human cancer cell lines and patients' samples. In addition to conferring malignant phenotype to cells, it enhances resistance to conventional anti-cancer drugs. Moreover, transcript levels of this lncRNA have been regarded as diagnostic markers in several cancer types including gastric, bladder and liver cancers. The underlying mechanism of its participation in carcinogenesis has been identified in some cancer types. Sponging tumor suppressor miRNAs, interacting with cancer-promoting signaling pathways and enhancing cell cycle progression are among these mechanisms. Although few studies have shown anti-carcinogenic properties for this lncRNA, the bulk of evidence supports its oncogenic roles. In the current study, we have reviewed the current literature on the role of UCA1 in the carcinogenic process based on the results of in vitro studies, investigations in animal models and assessment of UCA1 expression in clinical samples.

LncRNA UCA1 affects epithelial-mesenchymal transition, invasion, migration and apoptosis of nasopharyngeal carcinoma cells

Objective: In this study, long non-coding RNA urothelial carcinoma associated 1 (lncRNA UCA1) in nasopharyngeal carcinoma (NPC) and its effect on the malignant phenotype of NPC cells was investigated. Methods: Initially, the expression of UCA1 in NPC tissues and cells was detected. NPC cell line that with highest expression of UCA1 was selected for subsequent cell function test. A series of experiments were used to detect proliferation, colony formation, cell cycle distribution, apoptosis, invasion and migration of NPC cells with the interference of UCA1 expression. Western blot analysis was carried out to detect the expression of E-cadherin and vimentin for verifying the effect of UCA1 on epithelial mesenchymal transition (EMT). Results: The expression of UCA1 was found to be upregulated in NPC tissues and cells. The expression of UCA1 in stage Ⅲ + IV of NPC tissues and in patients with lymph node metastasis was significantly higher than that in patients at stage Ⅰ + Ⅱ and in patients without lymph node metastasis. Inhibition of UCA1 repressed proliferation, EMT, colony formation, invasion and migration while stimulating apoptosis of NPC cells. Conclusion: Our study suggests that UCA1 expression was overexpressed in NPC. Additionally, UCA1 suppression could inhibit proliferation, EMT, invasion and migration, and promote apoptosis of NPC cells.

The prognostic value and mechanisms of lncRNA UCA1 in human cancer

Long noncoding RNAs (lncRNAs), longer than 200 nucleotides in length, play important roles in the development and progression of various cancers. An increasing number of studies have revealed that lncRNAs function as potential oncogenes or tumor suppressors to influence biological processes, such as cell growth, invasion, migration and apoptosis. Urothelial carcinoma associated 1 (UCA1), an oncogenic lncRNA, was first found in bladder cancer and highly expressed in multiple cancers, including gastric cancer, colorectal cancer, lung cancer and breast cancer. UCA1 promotes tumorigenesis mainly via binding to tumor-suppressive microRNAs (miRNAs), activating several pivotal signaling pathways and alteration of epigenetic and transcriptional regulation. In addition, high expression of UCA1 is related to poor clinicopathological features especially for shorter overall survival, suggesting that UCA1 might be regarded as a prognosis biomarker in human cancers. In the present review, we summarized current studies on UCA1 to explore its prognostic value and underlying regulation mechanisms in the development of multiple cancers in order to provide a glimmer of hope for the prevention and treatment of malignant tumors.

Crosstalk between the lncRNA UCA1 and microRNAs in cancer

Long non-coding RNAs (lncRNAs) are a major subset of highly conserved non-coding RNAs (ncRNAs) that consist of at least 200 nucleotides and have limited protein-coding potential. Cumulative data have shown that lncRNAs are deregulated in many types of cancer and may control pathophysiological processes of cancer at various levels, including transcription, post-transcription and translation. Recently, lncRNAs have been demonstrated to interact with microRNAs (miRNAs), another major subset of ncRNAs, which regulate physiological and pathological processes by inhibiting target mRNA translation or promoting mRNA degradation. The lncRNA urothelial carcinoma-associated 1 (UCA1) has recently gained much attention as it is overexpressed in many types of cancer and is involved in carcinogenesis. Here, we review the crosstalk between UCA1 and miRNAs during the pathogenesis of cancer, with a focus on cancer-cell proliferation, invasion, drug resistance, and metabolism.

The Long Noncoding RNA UCA1 Negatively Regulates Melanogenesis in Melanocytes

The long noncoding RNA UCA1 was first discovered in bladder cancer and is known to regulate the proliferation and migration of melanoma. However, its role in melanogenesis is unclear. In this study, we aimed to explore the role and mechanism of UCA1 in melanogenesis. Our findings showed that the expression of UCA1 was negatively correlated with melanin content in melanocytes and pigmented nevus. Overexpression of UCA1 in melanocytes decreased melanin content and the expression of melanogenesis-related genes, whereas knockdown of UCA1 in melanocytes had the opposite effect. High-throughput sequencing revealed that microphthalmia-associated transcription factor (MITF), an important transcription factor affecting melanogenesis, was also negatively correlated with the expression of UCA1. Furthermore, the transcription factor CRE-binding protein (CREB), which promotes MITF expression, was negatively regulated by UCA1. The cAMP/protein kinase A (PKA), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) signaling pathways, which are upstream of the CREB/MITF/melanogenesis axis, were activated or inhibited in response to silencing or enhancing UCA1 expression, respectively. In addition, enhanced UCA1 expression downregulates the expression of melanogenesis-related genes induced by UVB in melanocytes. In conclusion, UCA1 may negatively regulate the CREB/MITF/melanogenesis axis through inhibiting the cAMP/PKA, ERK, and JNK signaling pathways in melanocytes. UCA1 may be a potential therapeutic target for the treatment of pigmented skin diseases.

Linc00210 enhances the malignancy of thyroid cancer cells by modulating miR-195-5p/IGF1R/Akt axis

Emerging evidence has indicated that long noncoding RNA (lncRNAs) play crucial roles in regulating thyroid cancer (TC) development. Linc00210 is a newly identified lncRNA which plays an oncogenic role in hepatocellular carcinoma and nasopharyngeal carcinoma, but whether Linc00210 can modulate the development of TC remains elusive. Here, we found that Linc00210 expression was upregulated in TC tissues compared to the matched noncancerous tissues. Overexpression of Linc00210 augmented the proliferation, migration, and invasion of TC cells. Mechanistically, Linc00210 served as a sponge for miR-195-5p, thereby counteracting its ability in downregulating the expression of IGF1R and the activation of PI3K/Akt signaling. Moreover, inhibition of Linc00210 suppressed the growth of TC cells in nude mice. Our findings for the first time uncovered the oncogenic property of Linc00210 in TC.

Dysregulated N6-methyladenosine methylation writer METTL3 contributes to the proliferation and migration of gastric cancer

Accumulating evidence implies that N6-methyladenosine (m6A) methylation participated in the tumorigenesis of gastric cancer (GC). Here we synthetically analyzing the prognostic value and expression profile of seven m6A methylation-relevant genes through silico analysis of sequencing data downloaded from The Cancer Genome Atlas, Kaplan-Meier plotter, and Gene Expression Omnibus database. We explored the methyltransferase-like 3 (METTL3) expression in GC cell line and tumor tissues by reverse transcription quantitative polymerase chain reaction and western blot analysis. The m6A methylation status of total RNA was measured by m6A RNA methylation quantification kit. Small interfering RNA was used to establish METTL3 knockdown cell lines. We also measure the proliferation and migration capability GC cell. Furthermore, we detect the epithelial cell mesenchymal transition marker and m6A methylation level after METTL3 knock down. Our result revealed that METTL3 was significantly increased in GC tissues compared with control in big crowd data sets. Survival analysis showed that METTL3 serve as a poor prognostic factor for GC patients. The expression level of METTL3 gradually increased with the progress of tumor stage and grade. GFI1 is an important transcription factor associated with METTL3. We verified the up-trend of METTL3 in messenger RNA and protein expression and observed a significant increase in the m6A methylation status of total RNA in the GC cells and tissues. METTL3 knockdown inhibited total RNA m6A methylation level, as well as cell proliferation and migration capacity. Moreover, METTL3 knockdown decreased α-smooth muscle actin. Taken together, our finding revealed that m6A methylation writer METTL3 serve as an oncogene in tumorigenesis of GC.

The Association of HOTAIR with the Diagnosis and Prognosis of Gastric Cancer and Its Effect on the Proliferation of Gastric Cancer Cells

BACKGROUND

Long noncoding RNAs (lncRNAs) are a group of noncoding RNA with the length of more than 200nt. They have been identified as important diagnostic and prognostic molecules for many cancers and play an important role in the development of cancers. However, their clinical value and roles in gastric cancer (GC) remain unclear.

METHODS

The expression levels of HOTAIR in 54 GC tissues and their matched adjacent nontumor tissues from GC patients and 24 normal mucosa or those with minimal gastritis as healthy controls were determined by qRT-PCR. The expression levels of HOTAIR in human GC cell lines and a normal gastric epithelium cell line were also assessed by qRT-PCR. The potential relationships between its level in GC tissues and the clinicopathological features were analyzed. Furthermore, a receiver operating characteristic (ROC) curve was constructed. Additionally, the correlation between this lncRNA and overall survival (OS) was analyzed. SiRNA transfection was used to silence the expression of HOTAIR in GC cells. And cell proliferation and cell cycle assays were employed to determine the effect of HOTAIR on GC cell growth. Western blot was performed for the detection of the P53, P21, and Bcl2 proteins.

RESULTS

The expression levels of HOTAIR were significantly upregulated in GC tissues and cell lines. Increased HOTAIR was associated with tumor differentiation, lymph node and distant metastasis, and clinical stage. Furthermore, the area under the ROC curve (AUC) was up to 0.8416 (95 % CI=0.7661 to 0.9170, P<0.0001). The sensitivity and specificity were 66.67 and 87.04%, respectively. The correlation between HOTAIR expression and overall survival (OS) was statistically significant. The hazard ratio was 2.681, and 95% CI of ratio was 1.370 to 5.248. In addition, knockdown of HOTAIR can inhibit GC cell growth and affect cell cycle distribution. And knockdown of HOTAIR could enhance the protein levels of P21 and P53.

CONCLUSION

The present study demonstrated that HOTAIR was highly expressed in GC tissues and may serve as a potential diagnostic and prognostic biomarker for GC. And HOTAIR promoted GC cell proliferation.

Long noncoding RNA UCA1 as a novel biomarker of lymph node metastasis and prognosis in human cancer: a meta-analysis

Background: Urothelial carcinoma associated 1 (UCA1), a novel long noncoding RNA (lncRNA) which is first discovered in 2006 in human bladder cancer and has become a hot spot in recent years. UCA1 has been demonstrated correlated with clinical outcomes in various cancers. However, the results from each study are insufficient and not completely consistent. Therefore, we perform a systematic meta-analysis to evaluate the value for a feasible biomarker for metastasis and prognosis of cancer. Methods: Relevant English literatures were searched in PubMed, Cochrane Library, Web of science, Embase databases and Chinese literatures were searched in Chinese National Knowledge Infrastructure Wanfang from inception up to 17 April 2018. The pooled odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) using random/fixed-effect were used to identify the relationship between UCA1 and lymph node metastasis (LNM) or overall survival (OS) of cancer patients. Subgroup analysis and sensitivity analysis were performed. The current meta-analysis was performed using Review Manager 5.3 and Stata 12.0 software. Results: A total of 3411 patients from 38 studies were finally included. Patients who with high UCA1 expression suffered from an increased risk of LNM (OR = 2.50; 95% CI: 1.93–3.25). UCA1 was also significantly associated with OS (HR = 2.05; 95% CI: 1.77–2.38). Subgroup analyses across several different variables also showed the similar results in LNM and OS of cancer patients. Conclusion: High expression of UCA1 was linked with poor clinical outcome. UCA1 can serve as a potential molecular marker for metastasis and prognosis in different types of cancers.

EGR1-induced upregulation of lncRNA FOXD2-AS1 promotes the progression of hepatocellular carcinoma via epigenetically silencing DKK1 and activating Wnt/β-catenin signaling pathway

Long non-coding RNAs (lncRNAs) are regarded as a group of biomarkers in the initiation and development of various cancers, including hepatocellular carcinoma (HCC). LncRNA FOXD2-AS1 has been studied in human colorectal cancer and glioma as an oncogene. However, the function and mechanism of lncRNA FOXD2-AS1 in hepatocellular carcinoma are marked. In this study, we found that high expression of FOXD2-AS1 predicted poor prognosis of HCC patients in the TCGA database. The dysregulation of FOXD2-AS1 was determined in HCC tissues and cell lines by qRT-PCR. Functionally, silenced FOXD2-AS1 efficiently suppressed HCC progression by regulating cell proliferation, apoptosis, migration and epithelial-mesenchymal transition (EMT). Mechanistically, FOXD2-AS1 was found to be activated by the transcription factor EGR1. Furthermore, FOXD2-AS1 could activate the Wnt/β-catenin signaling pathway. The mechanism contributed to the interaction between FOXD2-AS1 and Wnt/β-catenin signaling pathway was analyzed. It was uncovered that FOXD2-AS1 enhanced the activity of Wnt/β-catenin signaling pathway by epigenetically silencing the inhibitor of Wnt/β-catenin signaling pathway (DKK1). Rescue assays demonstrated that DKK1 and Wnt/β-catenin signaling pathway involved in FOXD2-AS1-mediated HCC progression. In conclusion, our study demonstrated that EGR1-induced upregulation of lncRNA FOXD2-AS1 promotes the progression of hepatocellular carcinoma via epigenetically silencing DKK1 and activating Wnt/β-catenin signaling pathway.

lncRNA UCA1-Mediated Cdc42 Signaling Promotes Oncolytic Vaccinia Virus Cell-to-Cell Spread in Ovarian Cancer

Oncolytic vaccinia virus (OVV) has demonstrated appropriate safety profiles for clinical development. Although designed to kill cancer cells efficiently, OVV sensitivity varies in individual cancers, and predictive biomarkers of therapeutic responses have not been identified. Here we found that OVV was much more efficient in KFTX paclitaxel-resistant ovarian cancer cells compared to that in KFlow paclitaxel-sensitive cells. Microarray analysis identified long non-coding RNA urothelial carcinoma-associated 1 (UCA1) upregulation, which contributed to both enhanced paclitaxel resistance and OVV spread. In addition, UCA1 expression correlated with efficient OVV spread in other ovarian cell lines and primary cancer cell cultures. When host pathways underlying OVV spread were analyzed, differences were detected in the activation of the Rho GTPase Cdc42, suggesting that filopodia formation enhances OVV cell-to-cell spread and tumor migration. Moreover, we established a clinically relevant mouse model of peritoneal metastasis using KFTX or KFlow cells. Paclitaxel exerted anti-tumor effects on KFlow, but not KFTX, tumors. In mice bearing KFTX cells after paclitaxel failure, OVV treatment induced the regression of residual tumors and improved survival. Our findings demonstrated that UCA1 promotes OVV cell-to-cell spread in ovarian cancer, resulting in enhanced therapeutic outcome.

Long non-coding RNA TTN-AS1 facilitates tumorigenesis of papillary thyroid cancer through modulating the miR-153-3p/ZNRF2 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) are crucial modulators in the tumorigenesis of numerous cancers, including papillary thyroid cancer (PTC). However, it is unclear whether lncRNA TTN antisense RNA 1 (TTN-AS1) can regulate PTC progression. The present study aimed to reveal the mechanism and function of TTN-AS1 in PTC.

METHODS

TTN-AS1 expression in 92 pairs PTC tissues and four PTC cells was measured via a quantitative reverse transcriptase-polymerase chain reaction assay. The relationship of TTN-AS1 expression and clinical pathological features of PTC patients was analyzed using a chi-squared test. The biofunction of TTN-AS1 in PTC was identified by loss or gain-of-function assays. Based on bioinformatics analysis and mechanism experiments, the molecular mechanism of TTN-AS1 was analyzed and identified.

RESULTS

A high level of TTN-AS1 was observed in PTC tissues and cells. The expression level of TTN-AS1 is possibly associated with lymphatic metastasis, TNM stage and the overall survival of PTC patients. Functionally, TTN-AS1 knockdown inhibited cell proliferation, migration, invasion and epithelial-mesenchymal transition in PTC, whereas overexpression of TTN-AS1 led to the opposite results. Mechanistically, TTN-AS1 acted as a competing endogenous RNA by sponging microRNA-153-3p (miR-153-3p) to elevate zinc and ring finger 2 (ZNRF2) expression. Additionally, a high level of TTN-AS1 in PTC was closely correlated with the activity of the phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway.

CONCLUSIONS

The findings obtained in the present study indicate that TTN-AS1 facilitated PTC progression by regulating the miR-153-3p/ZNRF2 axis and activating the PI3K/Akt/mTOR pathway.

Silence of long non-coding RNA UCA1 inhibits hemangioma cells growth, migration and invasion by up-regulation of miR-200c

BACKGROUND

Human urothelial carcinoma associated 1 (UCA1) has been recognized as an oncogenic lncRNA in various cancers, except infantile hemangioma (IH). This study attempts to explore the functional role of lncRNA UCA1 in IH.

METHODS

qRT-PCR was carried out to detect the expression of lncRNA UCA1 in human IH tissues. Two hemangioma cell lines (EOMA and HemECs) were transfected with shRNAs specific for lncRNA UCA1, or a plasmid for expression lncRNA UCA1. The expression of miR-200c in cell was suppressed or overexpressed by miRNA-mediated transfection. CCK-8 assay, flow cytometry, Transwell assay, and Western blot were performed to detect cell survival, migration and invasion.

RESULTS

LncRNA UCA1 was up-regulated in proliferating-phase hemangioma samples, as compared to involuting-phase. Silence of lncRNA UCA1 significantly reduced EOMA cells viability, migration and invasion, and induced apoptosis. These observations were coupled with the down-regulations of CyclinD1, CDK6 and CDK4, the cleavage of caspase-3 and caspase-9, as well as the decreased expression levels of MMP-9 and Vimentin. miR-200c was highly expressed in lncRNA UCA1 silenced-cells. Besides, the anti-tumor effects of lncRNA UCA1 silence towards EOMA cells were reversed by miR-200c suppression. Same effects of lncRNA UCA1 and miR-200c on HemECs cells were observed. Furthermore, silence of lncRNA UCA1 repressed mTOR, AMPK and Wnt/β-catenin signaling via a miR-200c-dependent fashion.

CONCLUSION

This study evidences that silence of lncRNA UCA1 inhibits hemangioma cells growth, migration and invasion possibly via its regulation on miR-200c expression and the activation of mTOR, AMPK and Wnt/β-catenin signaling pathways.

Targeting PI3K in cancer: mechanisms and advances in clinical trials

Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling is one of the most important intracellular pathways, which can be considered as a master regulator for cancer. Enormous efforts have been dedicated to the development of drugs targeting PI3K signaling, many of which are currently employed in clinical trials evaluation, and it is becoming increasingly clear that PI3K inhibitors are effective in inhibiting tumor progression. PI3K inhibitors are subdivided into dual PI3K/mTOR inhibitors, pan-PI3K inhibitors and isoform-specific inhibitors. In this review, we performed a critical review to summarize the role of the PI3K pathway in tumor development, recent PI3K inhibitors development based on clinical trials, and the mechanisms of resistance to PI3K inhibition.

LONG-NONCODING RNAs in gastroesophageal cancers

Despite continuing improvements in multimodal therapies, gastro-esophageal malignances remain widely prevalent in the population and is characterized by poor overall and disease-free survival rates. Due to the lack of understanding about the pathogenesis and absence of reliable markers, gastro-esophageal cancers are associated with delayed diagnosis. The increasing understanding about cancer's molecular landscape in the recent years, offers the possibility of identifying 'targetable' molecular events and in particular facilitates novel treatment strategies and development of biomarkers for early stage diagnosis. At least 98% of our genome is actively transcribed into non-coding RNAs encompassing long non-coding RNAs (lncRNAs) constituted of transcripts longer than 200 nucleotides with no protein-coding capacity. Many studies have demonstrated that lncRNAs are functional genomic elements playing pivotal roles in main oncogenic processes. LncRNA can act at multiple levels developing a complex molecular network that can modulate directly or indirectly the expression of genes involved in tumorigenesis. In this review, we focus on lncRNAs as emerging players in gastro-esophageal carcinogenesis and critically assess their potential as reliable noninvasive biomarkers and in next generation targeted therapies.

LncRNA UCA1 promotes tumor metastasis by inducing miR-203/ZEB2 axis in gastric cancer

Increasing studies showed that long-noncoding RNAs (lncRNAs) play important roles in the biological processes, including cancer initiation and progression. However, little is known about the exact role and regulation mechanism of lncRNA UCA1 during the progression of gastric cancer (GC). In this study, we found that UCA1 was aberrantly elevated in gastric cancer tissues, and was significantly associated with lymph node metastasis and TNM stage. In vivo and in vitro, enforced UCA1 level promoted cell migration and invasion of GC cell. Depleted UCA1 expression level attenuated the ability of cell migration and invasion in GC. And then, we detected that expression level of ZEB2, a transcription factor related to tumor metastasis, was regulated by UCA1 in GC cells. miR-203 targets and suppresses to ZEB2 expression. Furthermore, we found that UCA1 could directly interact with miR-203 and lead to the release of miR-203-targeted transcripts ZEB2. Herein, we revealed the novel mechanism of UCA1 on regulating metastasis-related gene by sponge regulatory axis during GC metastasis. Our findings indicated that UCA1 plays a critical role in metastatic GC by mediating sponge regulatory axis miR-203/ZEB2. To explore function of UCA1-miR-203-ZEB2 axis may provide an informative biomarker of malignancy and a highly selective anti-GC therapeutic target.

Epigenetic Regulation by lncRNAs: An Overview Focused on UCA1 in Colorectal Cancer

Colorectal cancers have become the second leading cause of cancer-related deaths. In particular, acquired chemoresistance and metastatic lesions occurring in colorectal cancer are a major challenge for chemotherapy treatment. Accumulating evidence shows that long non-coding (lncRNAs) are involved in the initiation, progression, and metastasis of cancer. We here discuss the epigenetic mechanisms through which lncRNAs regulate gene expression in cancer cells. In the second part of this review, we focus on the role of lncRNA Urothelial Cancer Associated 1 (UCA1) to integrate research in different types of cancer in order to decipher its putative function and mechanism of regulation in colorectal cancer cells. UCA1 is highly expressed in cancer cells and mediates transcriptional regulation on an epigenetic level through the interaction with chromatin modifiers, by direct regulation via chromatin looping and/or by sponging the action of a diversity of miRNAs. Furthermore, we discuss the role of UCA1 in the regulation of cell cycle progression and its relation to chemoresistance in colorectal cancer cells.

Interaction of long-chain non-coding RNAs and important signaling pathways on human cancers (Review)

Long non-coding RNAs (lncRNAs) usually refer to non-coding RNA transcripts >200 nucleotides in length. In terms of the full genomic transcript, the proportion of lncRNAs far exceeds that of coding RNA. Initially, lncRNAs were considered to be the transcriptional noise of genes, but it has since been demonstrated that lncRNAs serve an important role in the regulation of cellular activities through interaction with DNA, RNA and protein. Numerous studies have demonstrated that various intricate signaling pathways are closely related to lncRNAs. Here, we focus on a large number of studies regarding the interaction of lncRNAs with important signaling pathways. It is comprehensively illustrated that lncRNAs regulate key metabolic components and regulatory factors of signaling pathways to affect the biological activities of tumor cells. Evidence suggests that the abnormal expression or mutation of lncRNAs in human tumor cells, and their interaction with signaling pathways, may provide a basis and potential target for the diagnosis and treatment of human cancers.

LncRNA CASC11 promoted gastric cancer cell proliferation, migration and invasion in vitro by regulating cell cycle pathway

In this study, we aimed to investigate the effects of lncRNA CASC11 on gastric cancer (GC) cell progression through regulating miR-340-5p and cell cycle pathway. Expressions of lncRNA CASC11 in gastric cancer tissues and cell lines were determined by qRT-PCR. Differentially expressed lncRNAs, mRNAs and miRNAs were screened through microarray analysis. The relationship among CASC11, CDK1 and miR-340-5p was predicted by TargetScan and validated through dual luciferase reporter assay. Western blot assay examined the protein level of CDK1 and several cell cycle regulatory proteins. GO functional analysis and KEGG pathway analysis were used to predict the association between functions and related pathways. Cell proliferation was determined by CCK-8 assays. Cell apoptosis and cell cycle were detected by flow cytometry assay. CASC11 was highly expressed in GC tissues and cell lines. Knockdown of CASC11 inhibited GC cell proliferation, promoted cell apoptosis and blocked cell cycle. KEGG further indicated an enriched cell cycle pathway involving CDK1. QRT-PCR showed that miR-340-5p was down-regulated in GC cells tissues, while CDK1 was up-regulated. Furthermore, CASC11 acted as a sponge of miR-340-5p which directly targeted CDK1. Meanwhile, miR-340-5p overexpression promoted GC cell apoptosis and induced cell cycle arrest, while CDK1 overexpression inhibited cell apoptosis and accelerated cell cycle. Our study revealed the mechanism of CASC11/miR-340-5p/CDK1 network in GC cell line, and suggested that CASC11 was a novel facilitator that exerted a biological effect by activating the cell cycle signaling pathway. This finding provides a potential therapeutic target for GC.

Z Probe, An Efficient Tool for Characterizing Long Non-Coding RNA in FFPE Tissues

Formalin-fixed paraffin embedded (FFPE) tissues are a valuable resource for biomarker discovery in order to understand the etiology of different cancers and many other diseases. Proteins are the biomarkers of interest with respect to FFPE tissues as RNA degradation is the major challenge in these tissue samples. Recently, non-protein coding transcripts, long non-coding RNAs (lncRNAs), have gained significant attention due to their important biological actions and potential involvement in cancer. RNA sequencing (RNA-seq) or quantitative reverse transcription-polymerase chain reaction (qRT-PCR) are the only validated methods to evaluate and study lncRNA expression and neither of them provides visual representation as immunohistochemistry (IHC) provides for proteins. We have standardized and are reporting a sensitive Z probe based in situ hybridization method to visually identify and quantify lncRNA in FFPE tissues. This assay is highly sensitive and identifies transcripts visible within different cell types and tumors. We have detected a scarcely expressed tumor suppressor lncRNA NRON (non-coding repressor of nuclear factor of activated T-cells (NFAT)), a moderately expressed oncogenic lncRNA UCA1 (urothelial cancer associated 1), and a highly studied and expressed lncRNA MALAT1 (metastasis associated lung adenocarcinoma transcript 1) in different cancers. High MALAT1 staining was found in colorectal, breast and pancreatic cancer. Additionally, we have observed an increase in MALAT1 expression in different stages of colorectal cancer.

Long non‑coding RNA HR1 participates in the expression of SREBP‑1c through phosphorylation of the PDK1/AKT/FoxO1 pathway

Sterol regulatory element binding protein‑1c (SREBP‑1c), which serves an essential role in the process of fat synthesis, is a key adjustment factor that regulates the dynamic balance of lipid metabolism. SREBP‑1c activates the transcription of multiple genes encoding for enzymes involved in the synthesis of triglycerides (TG) and fatty acids (FA) and accelerates lipid synthesis. Previous analysis indicated that long non‑coding RNA HCV regulated 1 (lncHR1) participates in lipid metabolism in vivo and regulates the level of SREBP‑1c protein. However, the mechanism of lncHR1 in regulating SREBP‑1c levels has not been revealed. In the present study, a fatty degeneration cell model was used to study how lncHR1 regulates the SREBP‑1c protein at the cellular level. Furthermore TG accumulation was assessed according to morphological analysis. Reverse transcription‑quantitative polymerase chain reaction and western blotting were used to detected the expression of SREBP‑1c. An activator and an inhibitor of phosphoinositide 3‑kinase/AKT phosphorylation (IGF‑1 and LY294002, respectively) were used to study the effect of lncHR1 on this pathway. It was verified that lncHR1 regulated SREBP‑1c levels and the phosphorylation of AKT in the steatosis cell model. Detailed molecular mechanisms mediated by lncHR1 were associated with the phosphorylation AKT/FoxO1 in Huh7 cell lines. Simultaneously, lncHR1 affected the location of FoxO1 inside and outside of the nucleus. Furthermore, the phosphorylation of PDK1 upstream of AKT was regulated through overexpression or knockdown lncHR1, as determined by western blotting. Taken together, these data show that lncHR1 inhibits SREBP‑1c levels through the phosphorylation of the PDK1/AKT/FoxO1 axis.

LncRNA UCA1 sponges miR-204-5p to promote migration, invasion and epithelial-mesenchymal transition of glioma cells via upregulation of ZEB1

Long non-coding RNA urothelial carcinoma associated 1 (lncRNA UCA1) promotes cancer progression and enhances chemoresistance through miR-204-5p in a few cancers. However, no studies have investigated whether UCA1 regulates glioma metastasis through miR-204-5p and its target. In the present study, cell migration, invasion and epithelial-mesenchymal transition (EMT) were evaluated in glioma cells overexpressing UCA1. The relationships among UCA1, miR-204-5p and ZEB1 were examined by real-time PCR, western blotting and dual-luciferase reporter assays. The effect of UCA1 knockdown on xenograft tumor growth was investigated. The levels of miR-204-5p, fibronectin, COL5 A1 and ZEB1 in tumor tissues were also determined. The results showed that UCA1 overexpression promoted cell migration, invasion and EMT. UCA1 interacted with miR-204-5p and decreased its level. ZEB1 was identified as a direct target of miR-204-5p and miR-204-5p negatively regulated ZEB1 expression. Moreover, UCA1 sponged miR-204-5p and partially rescued the inhibitory effect of miR-204-5p on ZEB1. In our in vivo studies, UCA1 knockdown reduced tumor volume and tumor weight. In addition, the levels of fibronectin, COL5 A1 and ZEB1 were decreased, while miR-204-5p level was increased. The present study provides the first evidence that UCA1 promotes glioma metastasis through the miR-204-5p/ZEB1 axis, contributing to the understanding of the pathogenesis of glioma.