LncRNAs in pancreatic cancer

Deciphering the molecular mechanism of long non-coding RNA HIF1A-AS1 regulating pancreatic cancer cells

Background

HIF1A-AS1, an antisense transcript of HIF1α gene, is a 652-bp LncRNA that is globally expressed in multiple tissues of animals. Recent evidence indicated that HIF1A-AS1 was involved in tumorigenesis of several types of cancer. However, the role of lncRNA in PC has not been reported, and the molecular mechanism remains elusive.

Results

In order to investigate the role of HIF1A-AS1 in PC, it was overexpressed in some PC cell lines (PANC-1, PATU8988 and SW1990), and a series of experiments including cell viability detection, flow cytometry, transwell migration, clone formation and wound healing were performed. Functionally, the results indicated that overexpression of HIF1A-AS1 could greatly inhibit proliferation and migration and promote apoptosis of PC cells. Moreover, the isobaric tags for relative and absolute quantification (iTRAQ) quantitative proteomics analysis was implemented to explore the underlying mechanism and the results indicated that OE of HIF1A-AS1 globally affected the expression levels of multiple proteins associated with metabolism of cancer. At last, the network analysis revealed that most of these differentially expressed proteins (DEPs) were integrated and severed essential roles in regulatory function. In view of this, we guessed HIF1A-AS1 overexpression induced the dysfunction of metabolism and disordered proteins' translation, which may account for its excellent tumour suppressor effect.

Conclusions

HIF1A-AS1 altered the cell function of PC cell lines via affecting the expression of numerous proteins. In summary, HIF1A-AS1 may exhibit a potential therapeutic effect on PC, and our study provided useful information in this filed.

Identification of Long Noncoding RNAs Expression Profiles Between Gallstone and Gallbladder Cancer Using Next-Generation Sequencing Analysis

Background

Gallstone disease (GS) is an important risk factor for Gallbladder cancer (GBC). However, the mechanisms of the progression of GS to GBC remain unclear. Long non-coding RNA (lncRNA), modulates DNA/RNA/proteins at epigenetic, pre-transcriptional, transcriptional and posttranscriptional levels, and plays a potential therapeutic role in various diseases. This study aims to identify lncRNAs that have a potential impact on GS-promoted GBC progression.

Methods and Results

Six GBC patients without GS, six normal gallbladder tissues, nine gallstones and nine GBC patients with GS were admitted to our hospital. The next-generation RNA-sequencing was performed to analyze differentially expressed (DE) lncRNA and messenger RNA (mRNA) in four groups. Then overlapping and specific molecular signatures were analyzed. We identified 29 co-DEGs and 500 co-DElncRNAs related to gallstone or GBC. The intersection and concatenation of co-DEGs and co-DElncRNA functionally involved in focal adhesion, Transcriptional misregulation in cancers, Protein digestion and absorption, and ECM-receptor interaction signaling pathways may contribute to the development of gallbladder cancer. Further exploration is necessary for early diagnosis and the potential treatment of GBC. FXYD2, MPZL1 and PAH were observed in both co-DEGs and co-DElncRNA and validated by qRT-PCR.

Conclusion

Our data identified a series of DEGs and DElncRNAs, which were involved in the progression of GBC and GS-related metabolism pathways. Compared to GBC, the GS profile was more similar to para-tumor tissues in transcriptome level and lower risk of cancer. Further exploration is necessary from GBC patients with different periods of follow-up gallstone.

Silencing long noncoding RNA LINC01133 suppresses pancreatic cancer through regulation of microRNA-1299-dependent IGF2BP3

The deregulation of long noncoding RNAs (lncRNAs) holds great potential in the treatment of multiple cancers, including pancreatic cancer (PC). However, the specific molecular mechanisms by which LINC01133 contributes to pancreatic cancer remain unknown. Subsequent to bioinformatics analysis, we predicted and analyzed differentially expressed lncRNAs, microRNAs, and genes in pancreatic cancer. We determined the expression patterns of LINC01133, miR-1299, and insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) in pancreatic cancer cells, and validated their interactions through luciferase reporter and RNA immunoprecipitation assays. We implemented loss-of-function and gain-of-function experiments for LINC01133, miR-1299, and IGF2BP3 to assay their potential effects on pancreatic cancer cell functions. We observed high expression of LINC01133 and IGF2BP3, but low expression of miR-1299, in pancreatic cancer cells. Furthermore, we found that LINC01133 enhances IGF2BP3 through binding with miR-1299. Silencing LINC01133 or IGF2BP3 and/or overexpressing miR-1299 limited pancreatic cancer cell proliferation, invasion, epithelial-mesenchymal transition, and suppressed tumorigenic abilities in mice lacking T cells (nude mice). Overall, our findings identified that silencing LINC01133 downregulates IGF2BP3 by upregulating miR-1299 expression, ultimately leading to the prevention of pancreatic cancer.

Microbiome and MicroRNA or Long Non-Coding RNA-Two Modern Approaches to Understanding Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of humans' most common and fatal neoplasms. Nowadays, a number of PDAC studies are being conducted in two different fields: non-coding RNA (especially microRNA and long non-coding RNA) and microbiota. It has been recently discovered that not only does miRNA affect particular bacteria in the gut microbiome that can promote carcinogenesis in the pancreas, but the microbiome also has a visible impact on the miRNA. This suggests that it is possible to use the combined impact of the microbiome and noncoding RNA to suppress the development of PDAC. Nevertheless, insufficient research has focused on bounding both approaches to the diagnosis, treatment, and prevention of pancreatic ductal adenocarcinoma. In this article, we summarize the recent literature on the molecular basis of carcinogenesis in the pancreas, the two-sided impact of particular types of non-coding RNA and the pancreatic cancer microbiome, and possible medical implications of the discovered phenomenon.

Multi-level integrative analysis of the roles of lncRNAs and differential mRNAs in the progression of chronic pancreatitis to pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors and approximately 5% of patients with chronic pancreatitis (CP) inevitably develop PDAC. This study aims explore the key gene regulation involved in the progression of CP to PDAC, with a particular emphasis on the function of lncRNAs.

RESULTS

A total of 103 pancreatic tissue samples collected from 11 to 92 patients with CP and PDAC, respectively, were included in this study. After normalizing and logarithmically converting the original data, differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEGs) in each dataset were selected. To determine the main functional pathways of differential mRNAs, we further annotated DEGs using gene ontology (GO) and analyzed the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. In addition, the interaction between lncRNA-miRNA-mRNA was clarified and the protein-protein interaction (PPI) network was constructed to screen for key modules and determine hub genes. Finally, quantitative real-time polymerase chain reaction (qPCR) was used to detect the changes in non-coding RNAs and key mRNAs in the pancreatic tissues of patients with CP and PDAC. In this study, 230 lncRNAs and 17,668 mRNAs were included. There were nine upregulated lncRNAs and 188 downregulated lncRNAs. Furthermore, 2334 upregulated differential mRNAs and 10,341 downregulated differential mRNAs were included in the enrichment analysis. From the KEGG enrichment analysis, cytokine-cytokine receptor interaction, calcium signaling pathway, cAMP signaling pathway, and nicotine addiction exhibited significant differences. Additionally, a total of 52 lncRNAs, 104 miRNAs, and 312 mRNAs were included in the construction of a potential lncRNA-miRNA-mRNA regulatory network. PPI network was established and two of the five central DEGs were created in this module, suggesting that lysophosphatidic acid receptor 1 (LPAR1) and regulator of calcineurin 2 (RCAN2) may play significant roles in the progression from CP to PDAC. Finally, the PCR results suggested that LINC01547/hsa-miR-4694-3p/LPAR1 and LINC00482/hsa-miR-6756-3p/RCAN2 play important roles in the carcinogenesis process of CP.

CONCLUSION

Two signaling axes critical in the progression of CP to PDAC were screened out. Our findings will be useful for novel insights into the molecular mechanism and potential diagnostic or therapeutic biomarkers for CP and PDAC.

The role of LncRNA MCM3AP-AS1 in human cancer

Long noncoding RNAs (lncRNA) play pivotal roles in every level of gene and genome regulation. MCM3AP-AS1 is a lncRNA that has an oncogenic role in several kinds of cancers. Aberrant expression of MCM3AP-AS1 has been reported to be involved in the progression of diverse malignancies, including colorectal, cervical, prostate, lymphoma, lung, ovary, liver, bone, and breast cancers. It is generally believed that MCM3AP-AS1 expression is associated with cancer cell growth, proliferation, angiogenesis, and metastasis. MCM3AP-AS1 by targeting various signaling pathways and microRNAs (miRNAs) presents an important role in cancer pathogenesis. MCM3AP-AS1 as a competitive endogenous RNA has the ability to sponge miRNA, inhibit their expressions, and bind to different target mRNAs related to cancer development. Therefore, MCM3AP-AS1 by targeting several signaling pathways, including the FOX family, Wnt, EGF, and VEGF can be a potent target for cancer prediction and diagnosis. In this review, we will summarize the role of MCM3AP-AS1 in various human cancers.

Linc-UROD stabilizes ENO1 and PKM to strengthen glycolysis, proliferation and migration of pancreatic cancer cells

Pancreatic cancer (PC) is a fatal malignancy, threatening human health in worldwide. Long non-coding RNAs (lncRNAs) have been acknowledged to be essential regulators in various biological processes of human cancers. However, the role of some novel lncRNAs in PC remain to be explored. In this study, we focused on the function and molecular mechanism of a novel lncRNA linc-UROD (also named TCONS_00002016 or XLOC_000166) in PC. The expression of linc-UROD was found to be upregulated in PC cells. The results of loss-of-function assays demonstrated that linc-UROD knockdown suppressed cell proliferation and migration, induced cell cycle G0/G1 arrest, and accelerated apoptosis of PC cells. Through mechanistic experiments, we found that IGF2BP3 stabilized linc-UROD through METTL3-mediated m6A modification. In addition, linc-UROD enhances the stability of ENO1 and PKM through interacting with them to inhibit ubiquitination. Detection on glucose consumption, pyruvate kinase activity and lactate production indicated that linc-UROD accelerated glycolysis of PC cells through PKM/ENO1-mediated pathway. To summarize, linc-UROD stabilized by IGF2BP3/METTL3 contributes to glycolysis and malignant phenotype of PC cells by stabilizing ENO1 and PKM. The findings suggest that linc-UROD may be a novel therapeutic target for PC patients.

LncRNA KCNQ1OT1 enhances the radioresistance of lung squamous cell carcinoma by targeting the miR-491-5p/TPX2-RNF2 axis

BACKGROUND

Lung cancer, especially lung squamous cell carcinoma (LUSC), is one of the most common malignant tumors worldwide. Currently, radiosensitization research is a vital direction for the improvement of LUSC therapy. Long non-coding RNAs (lncRNAs) can be novel biomarkers due to their multiple functions in cancers. However, the function and mechanism of lncRNA KCNQ1OT1 in the radioresistance of LUSC remain to be elucidated.

METHODS

The clonogenic assay was employed to determine the radioresistance of SK-MES-1R and NCI-H226R cells. Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot were conducted for the detection of gene expression. Cell proliferation was determined by the methyl thiazolyl tetrazolium (MTT) assay, colony formation assay, and 5-ethynyl-2'-deoxyuridine (EdU) staining, and cell apoptosis was assessed by flow cytometry. The relationships between genes were also evaluated by applying the luciferase reporter and radioimmunoprecipitation (RIP) assays.

RESULTS

Radioresistant LUSC cells (SK-MES-1R and NCI-H226R) had strong resistance to X-ray irradiation, and lncRNA KCNQ1OT1 was highly expressed in SK-MES-1R and NCI-H226R cells. Moreover, knockdown of lncRNA KCNQ1OT1 prominently suppressed proliferation, attenuated radioresistance, and accelerated the apoptosis of SK-MES-1R and NCI-H226R cells. More importantly, we verified that miR-491-5p was a regulatory target of lncRNA KCNQ1OT1, and Xenopus kinesin-like protein 2 (TPX2) and RING finger protein 2 (RNF2) were the target genes of miR-491-5p. The rescue experiment results also demonstrated that miR-491-5p was involved in the inhibition of cell proliferation and the downregulation of TPX2 and RNF2 expression mediated by lncRNA KCNQ1OT1 knockdown in SK-MES-1R and NCI-H226R cells.

CONCLUSIONS

LncRNA KCNQ1OT1 was associated with the radioresistance of radioresistant LUSC cells, and the lncRNA KCNQ1OT1/miR-491-5p/TPX2-RNF2 axis might be used as a therapeutic target to enhance the radiosensitivity of radioresistant LUSC cells.

Integrative pan-cancer analysis indicates the prognostic importance of long noncoding RNA SNHG17 in human cancers

BACKGROUND

Cancer is one of the most widespread causes of death today. Early diagnosis can dramatically reduce cancer-related mortality. Studies have shown that the lncRNA Small Nucleolar RNA Host Gene 17 (SNHG17) is aberrantly expressed in various types of solid tumors. Nevertheless, its prognostic value remains to be elucidated. The main objective of this meta-analysis was to elucidate whether SNHG17 can be considered as a potential prognostic biomarker for a variety of cancers.

METHODS

Correlational studies were screened from Cochrane, Embase, PubMed, and Web of Science. Hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were pooled, and the role of SNHG17 in cancer was analyzed. The Cancer Genome Atlas (TCGA) database was employed to verify the results.

RESULTS

Seventeen original papers including 1451 patients were included in the meta-analysis. SNHG17 expression was upregulated in various cancers. Overexpression of SNHG17 was significantly correlated with worse overall survival (OS) (HR = 1.92, 95% CI 1.55-2.37, P < 0.001) and relapse-free survival (RFS) (HR = 1.87, 95% CI 1.06-3.30, P = 0.030). Furthermore, overexpression of SNHG17 was predictive of earlier lymph node metastasis (LNM) (OR = 2.94, 95% CI 2.29-3.78, P < 0.001), more advanced tumor-node-metastases (TNM) stage (OR = 3.56, 95% CI 2.22-5.68, P < 0.001), larger tumor size (OR = 2.18, 95% CI 1.65-2.88, P < 0.001), worse differentiation grade (OR = 1.69, 95% CI 1.26-2.25, P < 0.001), and earlier distant metastasis (DM) (OR = 1.63, 95% CI 1.03-2.56, P = 0.033) in human cancers. Moreover, further inquiry based on TCGA dataset validated that SNHG17 was high expression in various tumors and foresaw unfavorable clinical prognosis.

CONCLUSIONS

Overexpression of SNHG17 correlates with poor prognosis and advanced clinicopathological features in cancer patients and may be a potential prognostic indicator and a therapeutic target for cancer treatment.

LncRNA HEIH/miR-4500/IGF2BP1/c-Myc Feedback Loop Accelerates Bladder Cancer Cell Growth and Stemness

BACKGROUND

Bladder cancer (BCa) is one of the most prevalent malignancies and more common in men. An aberrantly expressed long noncoding RNA (lncRNA) hepatocellular carcinoma up-regulated EZH2-associated lncRNA (HEIH) has been reported to be implicated in the progression of many cancers, but its role in BCa remains little known. Our study intended to uncover whether and how HEIH regulates BCa progression.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction (RT-qPCR) was adopted to determine HEIH expression in BCa cell lines. Functional experiments were performed to examine the effects of HEIH on BCa cell proliferation, apoptosis, migration, invasion and stemness. Bioinformatics analysis and mechanism experiments were conducted to investigate the regulatory relationship between HEIH and related molecules in BCa.

RESULTS

HEIH expression was observed to be significantly increased in BCa cell lines. HEIH depletion significantly hindered BCa cell proliferation, migration and invasion. Besides, HEIH up-regulated MYC proto-oncogene, and bHLH transcription factor (c-Myc) expression to promote BCa cell stemness. Moreover, HEIH served as a sponge for miR-4500 to modulate insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) expression, thereby stabilizing c-Myc mRNA level.

CONCLUSION

Our study demonstrated a positive feedback loop of HEIH/miR-4500/IGF2BP1/c-Myc in BCa progression, offering a novel insight into a possible BCa therapy.

LINC00518 Promotes Cell Malignant Behaviors via Influencing EIF4A3-Mediated mRNA Stability of MITF in Melanoma

Melanoma has become the most severe sort of skin cancer, deriving from the pigment-producing melanocytes. Existing research has validated that long noncoding RNAs (lncRNAs) have critical function in the progression of cancers. LINC00518 has been studied in cutaneous melanoma; however, the molecular mechanism of LINC00518 in melanoma needs in-depth investigation. In our study, LINC00518 was revealed to be upregulated in melanoma tissues and cells, and melanoma patients in high LINC00518 expression group had poorer prognosis as depicted in GEPIA database. Functional assays revealed that LINC00518 depletion inhibited cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). Furthermore, MITF was confirmed to be upregulated in melanoma tissues and cells, and melanoma patients in high MITF expression group had poorer prognosis as displayed in GEPIA database. MITF expression was positively connected to LINC00518 expression. Additionally, results of mechanism assays uncovered EIF4A3 could bind with LINC00518 and MITF, and LINC00518 recruited EIF4A3 to stabilize MITF mRNA. Finally, it was demonstrated that upregulation of MITF could partially abrogate the inhibitory impact of LINC00518 knockdown on melanoma cell malignant behaviors. To summarize, LINC00518 promotes the malignant processes of melanoma cells through targeting EIF4A3/MITF axis, which might provide novel potential biomarkers for melanoma prognosis.

FOXP4-AS1 May be a Potential Prognostic Biomarker in Human Cancers: A Meta-Analysis and Bioinformatics Analysis

Background

Cancer is one of the leading causes of death worldwide. Early diagnosis can significantly lower cancer-related mortality. Studies have shown that the lncRNA Forkhead box P4 antisense RNA 1 (FOXP4-AS1) is aberrantly expressed in various solid tumors. A meta-analysis was performed to evaluate the correlation of FOXP4-AS1 with the prognosis of cancer patients and determine the clinical value of FOXP4-AS1 as a potential diagnostic marker.

Methods

Correlational studies from the Web of Science, Embase, OVID, Cochrane and PubMed databases were screened (up to April 1, 2021). Meta-analysis was performed using Stata SE12.0 software.

Results

Eleven original studies with 1,332 patients who were diagnosed with a solid cancer (nasopharyngeal carcinoma, hepatocellular carcinoma, colorectal cancer, gastric cancer, osteosarcoma, mantle cell lymphoma, prostate cancer, and pancreatic ductal adenocarcinoma) were included in the meta-analysis. High expression of FOXP4-AS1 was correlated with poor overall survival (OS) (HR = 1.77, 95% CI 1.29-2.44, P < 0.001) and shorter disease-free survival (DFS) (HR = 1.66, 95% CI 1.01-2.72, P = 0.044). Subgroup analysis based on sample size, follow-up time and Newcastle-Ottawa Scale (NOS) score revealed significant differences between FOXP4-AS1 levels and OS (P < 0.05). However, the expression level of FOXP4-AS1 was not significantly correlated with the OS of gastric cancer patients (P = 0.381). High expression of FOXP4-AS1 was predictive of a larger tumor size (OR = 3.82, 95% CI 2.3-6.3, P < 0.001).

Conclusions

Overexpression of FOXP4-AS1 correlates with poor prognosis of cancer patients, and is a potential prognostic biomarker and therapeutic target.

Systematic Review Registration

PROSPERO, identifier CRD42021245267.

Role of long non-coding RNAs in development and progression of pancreatic cancer

Pancreatic cancer is a kind of digestive tract malignant tumor that has high malignancy and is difficult to diagnose and treat. Recent studies have proved that long non-coding RNAs (lncRNAs) can mediate tumor genesis, proliferation, migration, and metastasis by regulating epigenetic modification, alternative splicing, transcription, and protein translation. LncRNAs play an important role in the occurrence and development of pancreatic cancer. In this review, we review the role of lncRNAs in pancreatic cancer to provide possible diagnostic and therapeutic targets for the treatment of this malignancy.

Integrative Analysis of 5-Hydroxymethylcytosine and Transcriptional Profiling Identified 5hmC-Modified lncRNA Panel as Non-Invasive Biomarkers for Diagnosis and Prognosis of Pancreatic Cancer

Pancreatic adenocarcinoma (PAAD) is the fourth leading cause of cancer-related deaths worldwide. 5-Hydroxymethylcytosine (5hmC)-mediated epigenetic regulation has been reported to be involved in cancer pathobiology and has emerged to be promising biomarkers for cancer diagnosis and prognosis. However, 5hmC alterations at long non-coding RNA (lncRNA) genes and their clinical significance remained unknown. In this study, we performed the genome-wide investigation of lncRNA-associated plasma cfDNA 5hmC changes in PAAD by plotting 5hmC reads against lncRNA genes, and identified six PAAD-specific lncRNAs with abnormal 5hmC modifications compared with healthy individuals. Then we applied machine-learning and Cox regression approaches to develop predictive diagnostic (5hLRS) and prognostic (5hLPS) models using the 5hmC-modified lncRNAs. The 5hLRS demonstrated excellent performance in discriminating PAAD from healthy controls with an area under the curve (AUC) of 0.833 in the training cohort and 0.719 in the independent testing cohort. The 5hLPS also effectively divides PAAD patients into high-risk and low-risk groups with significantly different clinical outcomes in the training cohort (log-rank test p = 0.04) and independent testing cohort (log-rank test p = 0.0035). Functional analysis based on competitive endogenous RNA (ceRNA) and enrichment analysis suggested that these differentially regulated 5hmC modified lncRNAs were associated with angiogenesis, circulatory system process, leukocyte differentiation and metal ion homeostasis that are known important events in the development and progression of PAAD. In conclusion, our study indicated the potential clinical utility of 5hmC profiles at lncRNA loci as valuable biomarkers for non-invasive diagnosis and prognostication of cancers.

Phytochemicals mediated modulation of microRNAs and long non-coding RNAs in cancer prevention and therapy

MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are two main categories of noncoding RNAs (ncRNAs) that can influence essential biological functions in various ways, as well as their expression and function are tightly regulated in physiological homeostasis. Additionally, the dysregulation of these ncRNAs seems to be crucial to the pathogenesis of human diseases. The latest findings indicate that ncRNAs execute vital roles in cancer initiation and progression, and the cancer phenotype can be reversed by modulating their expression. Available scientific discoveries suggest that phytochemicals such as polyphenols, alkaloids, terpenoids, and organosulfur compounds can significantly modulate multiple cancer-associated miRNAs and lncRNAs, thereby inhibiting cancer initiation and development. However, despite promising outcomes of experimental research, only a few clinical trials are currently being conducted to evaluate the therapeutic effectiveness of these compounds. Nevertheless, understanding phytochemical-mediated ncRNA regulation in cancer and the underlying molecular mechanisms on tumor pathophysiology can aid in the development of novel therapeutic strategies to combat this deadly disease.

Role of long intergenic non-protein coding RNA 00152 in pancreatic cancer glycolysis via the manipulation of the microRNA-185-5p/Krüppel-like factor 7 axis

The current study set out to investigate the role of long intergenic non-protein coding RNA (LINC) 00152 in pancreatic cancer (PC) cell glycolysis with the microRNA (miR)-185-5p/Krüppel-like factor 7 (KLF7) axis. Firstly, PC tissues and cells as well as the control ones were collected from 53 PC patients, and assessed for LINC00152 expression patterns. Besides, PC cells with the most differentially expressed LINC00152 were selected for further experiments. When LINC00152 was silenced or overexpressed, PC cell glucose consumption, lactic acid production, adenosine triphosphate and levels of glycolysis-associated enzymes were detected. In addition, the binding relation between LINC00152 and miR-185-5p as well as the target relation between miR-185-5p and KLF7 was clarified and validated. Additionally, xenograft transplantation was performed to confirm the in vitro experiments. It was found that LINC00152 was over-expressed in PC, and it predicted a poor prognosis. Besides, LINC00152 knockdown inhibited PC cell glycolysis. Moreover, LINC00152 could specifically targeted miR-185-5p. Meanwhile, LINC00152 exhaustion blocked PC cell glycolysis through the up-regulation of miR-185-5p. Lastly, LINC00152 inhibition targeted miR-185-5p to quench KLF7, therefore suppressing PC cell tumorigenesis and glycolysis. Collectively, our findings indicated that silencing LINC00152 restricted PC cell glycolysis via promoting miR-185-5p and reducing KLF7.

Long non-coding RNA XIST accelerates hepatic carcinoma progression by targeting the microRNA-320a/PIK3CA axis

The aim of the present study was to reveal the new molecular mechanism of long non-coding (lnc)RNA XIST in the development of hepatic carcinoma. A total of 69 patients with hepatic carcinoma were included. Hepatoma cell lines (SUN449), hepatoblastoma cell line (HepG2, Huh-6), liver cancer cell line (HepG2) and transformed human liver epithelial-2 cells (THLE-2) were used in the present study. A total 3 short hairpin RNA (sh)-lncRNA XIST sequences, overexpression vector (oe)-lncRNA XIST, microRNA (miR)-320a mimic, miR-320a inhibitor, PIK3CA inhibitor, and their corresponding controls were transfected in hepatic carcinoma cells. Reverse transcription-quantitative polymerase chain reaction was conducted to detect lncRNA-XIST, miR-320a and PIK3CA expression. Cell Counting Kit-8 assay and flow cytometry were undertaken to measure proliferation and apoptosis. Cell invasion and migration were detected by Transwell assays. Moreover, the binding of lncRNA XIST, PIK3CA and miR-320a were verified by luciferase reporter experiment and pull-down assay. Finally, a rescue assay was processed to confirm the effect of lncRNA-XIST, miR-320a and PIK3CA in the aforementioned processes. lncRNA XIST was highly expressed in hepatic carcinoma tissues and cells. The survival rate was significantly lower in the highly expressed lncRNA XIST group. shlncRNA XIST attenuated cell proliferation, invasion and migration, while increasing the apoptosis of hepatic carcinoma cells. The lncRNA XIST negatively targeted miR-320a, and miR-320a negatively regulated the expression of PIK3CA. The miR-320a mimic and PIK3CA inhibitor could recover the effect of oe-lncRNA in terms of the proliferation, invasion, migration and apoptosis of hepatic carcinoma cells. lncRNA XIST accelerates hepatic carcinoma progression by targeting the miR-320a/PIK3CA axis, which might provide the theoretical basis for the potential targeted therapy of hepatic carcinomas.

Long non-coding RNA ZFAS1 promotes pancreatic cancer proliferation and metastasis by sponging miR-497-5p to regulate HMGA2 expression

The lncRNA ZFAS1 plays a carcinogenic regulatory role in many human tumours, but it is rarely reported in pancreatic cancer. We identify the role and molecular mechanisms of ZFAS1 in pancreatic cancer. The expression of ZFAS1, miR-497-5p and HMGA2 in pancreatic cancer tissues was detected by qRT-PCR. Pancreatic cancer data in The Cancer Genome Atlas were also included in this study. CCK8, EdU, transwell and scratch wound assays were used to investigate the biological effects of ZFAS1 in pancreatic cancer cells. MS2-RIP, RNA pull-down, RNA-ChIP and luciferase reporter assays were used to clarify the molecular biological mechanisms of ZFAS1 in pancreatic cancer. The role of ZFAS1 in vivo was also confirmed via xenograft experiments. ZFAS1 was overexpressed in pancreatic cancer tissues. ZFAS1 promoted the growth and metastasis of pancreatic cancer cells, and miR-497-5p acted as a tumour suppressor gene in pancreatic cancer by targeting HMGA2. We also demonstrated that ZFAS1 exerts its effects by promoting HMGA2 expression through decoying miR-497-5p. We also found that ZFAS1 promoted the progression of pancreatic cancer in vivo by modulating the miR-497-5p/HMGA2 axis. In conclusion, this study revealed a new role for and the molecular mechanisms of ZFAS1 in pancreatic cancer, identifying ZFAS1 as a novel target for the diagnosis and treatment of pancreatic cancer.

Metastatic pancreatic cancer: Mechanisms and detection (Review)

Pancreatic cancer (PC) is a lethal malignancy. Its prevalence rate remains low but continues to grow each year. Among all stages of PC, metastatic PC is defined as late-stage (stage IV) PC and has an even higher fatality rate. Patients with PC do not have any specific clinical manifestations. Most cases are inoperable at the time-point of diagnosis. Prognosis is also poor even with curative-intent surgery. Complications during surgery, postoperative pancreatic fistula and recurrence with metastatic foci make the management of metastatic PC difficult. While extensive efforts were made to improve survival outcomes, further elucidation of the molecular mechanisms of metastasis poses a formidable challenge. The present review provided an overview of the mechanisms of metastatic PC, summarizing currently known signaling pathways (e.g. epithelial-mesenchymal transition, NF-κB and KRAS), imaging that may be utilized for early detection and biomarkers (e.g. carbohydrate antigen 19-9, prostate cancer-associated transcript-1, F-box/LRR-repeat protein 7 and tumor stroma), giving insight into promising therapeutic targets.

Prognostic role of HOTAIR in colorectal cancer: A meta-analysis

BACKGROUND

Colorectal cancer is one of the most common malignant tumors. It is essential to find biomarkers for the early detection and evaluation of tumor prognosis. In recent years, studies have revealed that the expression of Hox transcription antisense RNA (HOTAIR) increases in various cancers, including colorectal cancer. However, due to the small sample size of each study, the persuasiveness is not strong.

AIM

To perform a meta-analysis to explore the relationship between the expression of HOTAIR and the prognosis of colorectal cancer.

METHODS

PubMed, MEDLINE, CNKI, CBM, and The Cochrane Library were searched for articles published before December 2020 on the relationship between HOTAIR expression and the prognosis of patients with colorectal cancer. Two reviewers independently evaluated the quality of the included articles and extracted the data. The risk ratio (HR) of overall survival (OS) and the odds ratio of lymph node metastasis (LNM) and distant metastasis (DM) were calculated to evaluate the association strength.

RESULTS

Seven articles that met the inclusion criteria were included. Six of them compared the correlation between HOTAIR expression level and OS, and the results suggested that there existed a significant correlation between them (OR = 2.36, 95%CI: 1.74-3.19, P < 0.05). The correlation between HOTAIR expression level and LNM was compared in five articles, with a statistically significant correlation observed (OR = 4.07, 95%CI: 1.38-12.0, P < 0.05). Four articles compared the correlation between HOTAIR expression level and DM, and there was a statistically significant correlation between them (OR = 4.32, 95%CI: 1.60-11.62, P < 0.05).

CONCLUSION

The high expression of HOTAIR in colorectal cancer is significantly correlated with decreased OS, LNM, and DM, which indicates that HOTAIR may be a new biomarker for evaluating the prognosis of colorectal cancer.

The impact of LncRNA dysregulation on clinicopathology and survival of pancreatic cancer: a systematic review and meta-analysis (PRISMA compliant)

Purpose

An increasing number of studies have reported a significant association between long non-coding RNAs (lncRNAs) dysregulation and pancreatic cancers. In the present study, we aimed to gather articles to evaluate the prognostic value of long non coding RNA in pancreatic cancer.

Experimental design

We systematically searched all eligible articles from databases of PubMed, Web of Science, and Scopus to meta-analysis of published articles and screen association of multiple lncRNAs expression with clinicopathology and/or survival of pancreatic cancer. The pooled hazard ratios (HRs) and their 95% confidence intervals (95% CIs) were used to analysis of overall survival, disease-free survival and progression-free survival were measured with a fixed or random effects model.

Results

A total of 39 articles were included in the present meta-analysis. Our results showed that dysregulation of lncRNAs were linked to overall survival (39 studies, 4736 patients HR = 0.41, 95% CI 0.25 ± 0.58, random-effects in pancreatic cancer. Moreover, altered lncRNAs were also contributed to progression-free survival (8 studies, 1180 patients HR: 1.88, 95% CI (1.35–2.62) and disease-free survival (2 studies, 285 patients, HR: 6.07, 95% CI 1.28–28.78). In addition, our findings revealed the association between dysregulated RNAs and clinicopathological features in this type of cancer.

Conclusions

In conclusion, dysregulated lncRNAs could be served as promising biomarkers for diagnosis and prognosis of pancreatic cancer.

The Role of Long Noncoding RNA AL161431.1 in the Development and Progression of Pancreatic Cancer

Pancreatic cancer is known for its notorious fast progression and poor prognosis. Long noncoding RNA (lncRNA) AL161431.1 has been reported to be involved in the pathogenesis of different cancers. In this study, we explored the role of lncRNA AL161431.1 in the development and progression of pancreatic cancer by bioinformatic analysis, in vitro and in vivo experiments in pancreatic cancer BxPC-3 and SW1990 cells, as well as clinical samples. We found that lncRNA AL161431.1 was highly expressed in pancreatic cancer cells and tissues. Knock down of lncRNA AL161431.1 led to increased cancer cell death and cell cycle arrest. Xenograft growth of SW1990 cells with stable knockdown of lncRNA AL161431.1 in mice was significantly slower than that of SW1990 cells with scrambled control shRNA. Finally, we showed the involvement of lncRNA AL161431.1 in pancreatic cancer was related to its promotion of epithelial mesenchymal transition process.

Non-coding RNAs in pancreatic ductal adenocarcinoma: New approaches for better diagnosis and therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies with a 5-year survival rate less than 8%, which has remained unchanged over the last 50 years. Early detection is particularly difficult due to the lack of disease-specific symptoms and a reliable biomarker. Multimodality treatment including chemotherapy, radiotherapy (used sparingly) and surgery has become the standard of care for patients with PDAC. Carbohydrate antigen 19-9 (CA 19-9) is the most common diagnostic biomarker; however, it is not specific enough especially for asymptomatic patients. Non-coding RNAs are often deregulated in human malignancies and shown to be involved in cancer-related mechanisms such as cell growth, differentiation, and cell death. Several micro, long non-coding and circular RNAs have been reported to date which are involved in PDAC. Aim of this review is to discuss the roles and functions of non-coding RNAs in diagnosis and treatments of PDAC.

Plasma exosomal miR-375-3p regulates mitochondria-dependent keratinocyte apoptosis by targeting XIAP in severe drug-induced skin reactions

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe drug-induced cutaneous reactions characterized by keratinocyte apoptosis. Exosomes are nanometer-sized membranous vesicles in body fluids. They contain functional proteins, mRNAs, and miRNAs, which induce immune dysfunction and influence disease progression. However, their roles and mechanisms in SJS/TEN remain unknown. Our results demonstrate that exosomes isolated from the plasma of patients with SJS/TEN were 30 to 200 nm in diameter and expressed CD9, CD63, CD81, and TSG101 exosome marker proteins. miR-375-3p was markedly up-regulated in 35 patients with SJS/TEN and correlated with clinical severity. Plasma exosomes were internalized by human primary keratinocytes and promoted keratinocyte apoptosis in vitro. Furthermore, miR-375-3p overexpression promoted intrinsic (mitochondria-dependent) apoptosis of human primary keratinocytes via down-regulation of the X-linked inhibitor of apoptosis protein (XIAP), a key apoptosis regulator in primary human keratinocytes. In sum, our study indicates that the circulating exosomal miR-375-3p enters keratinocytes, down-regulates XIAP, and induces keratinocyte apoptosis in patients with SJS/TEN.

The Biological Function Delineated Across Pan-Cancer Levels Through lncRNA-Based Prognostic Risk Assessment Factors for Pancreatic Cancer

Long non-coding RNAs (lncRNAs) play key roles in tumors and function not only as important molecular markers for cancer prognosis, but also as molecular characteristics at the pan-cancer level. Because of the poor prognosis of pancreatic cancer, accurate assessment of prognosis is a key issue in the development of treatment plans for pancreatic cancer. Here we analyzed pancreatic cancer data from The Cancer Genome Atlas and The Genotype Tissue Expression database using Cox regression and lasso regression in analyses using a combination of the two databases as well as only The Cancer Genome Atlas database (Cancer Genome Atlas Research Network et al., 2013). A prognostic risk score model with significant correlation with pancreatic cancer survival was constructed, and two lncRNAs were investigated. Additional analysis of 33 cancers using the two lncRNAs showed that lncRNA TsPOAP1-AS1 was a prognostic marker of seven cancers, among which pancreatic cancer was the most significant, and lncRNA mi600hg was a prognostic marker of ovarian cancer and pancreatic cancer. LncRNA TsPOAP1-AS1 is associated with clinical stage and tumor mutation burden of some cancers as well as a strong degree of immune infiltration in many cancers, while a strong correlation between lncRNA mi600hg and microsatellite instability was observed in several cancers. The results of this study help further our understanding of the different functions of lncRNAs in cancer and may aid in the clinical application of lncRNAs as prognostic factors for cancer.

lncRNA ZFAS1 promotes the ox-LDL induced proliferation, invasion and migration of vascular smooth muscle cells

Atherosclerosis is a chronic progressive inflammatory vascular disease. The dysfunction of vascular smooth muscle cells (VSMCs) induced by oxidized low-density lipoprotein (ox-LDL) contributes to the formation of atherosclerotic lesions. Additionally, upregulation of the long non-coding RNA zinc finger antisense 1 (ZFAS1) was observed in the plaques of patients with atherosclerosis. The aim of the present study was to explore the functional role of ZFAS1 in atherosclerosis progression. Reverse transcription-quantitative PCR was performed to analyze ZFAS1 mRNA expression, and western blotting was performed to determine the protein expression levels of Ki67, proliferating cell nuclear antigen (PCNA), matrix metallopeptidase (MMP)2 and MMP9. The Cell Counting Kit-8 assay was used to test cell viability. Finally, wound healing and Transwell chamber assays were performed to evaluate cell migration and invasion, respectively. The current findings demonstrated that ZFAS1 expression was upregulated by ox-LDL stimulation in VSMCs. Moreover, ZFAS1 overexpression promoted the ox-LDL-induced proliferation, migration and invasion of VSMCs, and upregulated the expression levels of proteins associated with cellular proliferation (Ki67 and PCNA), migration and invasion (MMP2 and 9). By contrast, ZFAS1-knockdown inhibited the proliferation, migration and invasion of VSMCs, and suppressed cell proliferation-, migration- and invasion-associated protein expression. In conclusion, ZFAS1 promoted the ox-LDL-induced proliferation, invasion and migration of VSMCs. Thus, ZFAS1 may represent a novel biomarker for dysfunction of VSMCs in the pathological condition of atherosclerosis.

Extracellular Vesicles and Pancreatic Cancer: Insights on the Roles of miRNA, lncRNA, and Protein Cargos in Cancer Progression

Pancreatic cancer (PC) is among the most devastating digestive tract cancers worldwide. This cancer is characterized by poor diagnostic detection, lack of therapy, and difficulty in predicting tumorigenesis progression. Although mutations of key oncogenes and oncosuppressor involved in tumor growth and in immunosurveillance escape are known, the underlying mechanisms that orchestrate PC initiation and progression are poorly understood or still under debate. In recent years, the attention of many researchers has been concentrated on the role of extracellular vesicles and of a particular subset of extracellular vesicles, known as exosomes. Literature data report that these nanovesicles are able to deliver their cargos to recipient cells playing key roles in the pathogenesis and progression of many pancreatic precancerous conditions. In this review, we have summarized and discussed principal cargos of extracellular vesicles characterized in PC, such as miRNAs, lncRNAs, and several proteins, to offer a systematic overview of their function in PC progression. The study of extracellular vesicles is allowing to understand that investigation of their secretion and analysis of their content might represent a new and potential diagnostic and prognostic tools for PC.

Long noncoding RNAs: role and contribution in pancreatic cancer

Noncoding RNAs are proclaimed to be expressed in various cancer types and one such type is found to be pancreatic ductal adenocarcinoma (PDAC). The long noncoding RNAs (LncRNAs) affect the migration, invasion, and growth of tumor cells by playing important roles in the process of epigenesis, post-transcription, and transcriptional regulation along with the maintenance of apoptosis and cell cycle. It is quite subtle whether the alterations in lncRNAs would impact PDAC progression and development. This review throws a spotlight on the lncRNAs associated with tumor functions: MALAT-1, HOTAIR, HOXA13, H19, LINC01559, LINC00460, SNHG14, SNHG16, DLX6-AS1, MSC-AS1, ABHD11-AS1, DUXAP8, DANCR, XIST, DLEU2, etc. are upregulated lncRNAs whereas GAS5, HMlincRNA717, MIAT, LINC01111, lncRNA KCNK15-AS1, etc. are downregulated lncRNAs inhibiting the invasion and progression of PDAC. These data provided helps in the assessment of lncRNAs in the development, metastasis, and occurrence of PDAC and also play a vital role in the evolution of biomarkers and therapeutic agents for the treatment of PDAC.

Long non-coding RNA ELFN1-AS1 in the pathogenesis of pancreatic cancer

Background

Long non-coding ribonucleic acid (lncRNA) ELFN1 antisense RNA 1 (ELFN1-AS1) is involved in the pathogenesis of many different cancers. But the current research on the relationship between lncRNA ELFN1-AS1 and pancreatic cancer is still blank.

Methods

We investigated the role of lncRNA ELFN1-AS1 in the pathogenesis of pancreatic cancer using bioinformatics, in vitro and in vivo experiments in pancreatic cancer cell lines, and surgically removed clinical samples.

Results

Through bio-information analysis and in vitro and in vivo experiments, we found that LncRNA ELFN1-AS1 was highly enriched in pancreatic cancer data sets and highly expressed in pancreatic cancer cell lines and tissues. The knocking down of lncRNA ELFN1-AS1 significantly increased cancer cell death and growth arrest. Xenografts in nude mice showed that the growth of SW1990 cells in the mice group with a stable knock down of lncRNA ELFN1-AS1 was significantly slower than that in the control group.

Conclusions

The experimental results show that the expression of LncRNA ELFN1-AS1 is related to the growth and invasion ability of pancreatic cancer cells. By further studying the function of LncRNA ELFN1-AS1 in pancreatic cancer, LncRNA ELFN1-AS1 was found to be involved in the epithelial–mesenchymal transition process in pancreatic cancer.

Role of Curcumin in Regulating Long Noncoding RNA Expression in Cancer

Phytochemicals are various compounds produced by plants. There is growing evidence on their potential health effects. Some of these compounds are considered as traditional medicines and used as painkillers, anti-inflammatory agents, and for other applications. One of these phytochemicals is curumin, a natural polyphenol derived from the turmeric plant (Curcuma longa L.). Curcumin is widely used as a food coloring, preservative and condiment. It has also been shown to have antioxidative and anti-inflammatory effects. Moreover, there is growing evidence that curcumin alters long noncoding RNAs (lncRNAs) in many kinds of cancer. These noncoding RNAs can cause epigenetic modulation in the expression of several genes. This study reviews reports of curcumin effects on lncRNAs in lung, prostate, colorectal, breast, pancreatic, renal, gastric, and ovarian cancers.

LINC00671 suppresses cell proliferation and metastasis in pancreatic cancer by inhibiting AKT and ERK signaling pathway

Long noncoding RNAs (lncRNAs) represent an emerging field of tumor biology, playing essential roles in cancer cell proliferation, invasion, and metastasis. However, the overall functional and clinical significance of most lncRNAs in pancreatic cancer is not thoroughly understood. Here, we described most of the lncRNAs with aberrant expression patterns in pancreatic cancer as detected by microarray. Quantitative real-time polymerase chain reaction further verified that the expression of LINC00671 was decreased in pancreatic cancer cell lines and patient samples. Furthermore, lower LINC00671 expression was associated with reduced tumor differentiation, aggressiveness, and poor prognosis. Functionally, LINC00671 overexpression inhibited pancreatic cancer cell proliferation, invasion, and migration in vitro, and reduced tumor growth in vivo. LINC00671 is mainly located in the cytoplasm. RNA sequencing and bioinformatics analyses indicated that LINC00671 binds to multiple miRNAs and therefore could be involved in multiple tumor-associated pathways, such as the AMPK signaling pathway and PI3K-Akt signaling pathway. Western blotting and immunohistochemistry further confirmed that LINC00671 overexpression suppressed the AKT, ERK, and epithelial-mesenchymal transition pathways. Overall, these results indicated that LINC00671 acts as a novel tumor suppressor in pancreatic cancer. Our findings may provide a new potential target for the treatment of pancreatic cancer.

Long Noncoding RNA CERS6-AS1 Accelerates the Proliferation and Migration of Pancreatic Cancer Cells by Sequestering MicroRNA-15a-5p and MicroRNA-6838-5p and Modulating HMGA1

OBJECTIVES

As one of the most aggressive human tumors, pancreatic cancer (PC) is accompanied by poor treatment and prognosis. Although emerging evidence has highlighted the importance of long noncoding RNAs in multiple cancers, the specific regulatory roles mostly remain obscure. Our aim was to disclose the role of CERS6 antisense RNA 1 (CERS6-AS1) in PC.

METHODS

Quantitative real-time polymerase chain reaction analysis was used to examine the expression of CERS6-AS1 in PC cell lines. Western blot analysis was used to assess the protein levels of high-mobility group AT-hook 1 (HMGA1). Colony formation, 5-ethynyl-20-deoxyuridine, transwell, and wound healing assays were performed to detect the functions of CERS6-AS1 on PC development. In addition, RNA pull-down, RNA immunoprecipitation, and luciferase reporter assays were implemented to delve into the regulatory mechanism of CERS6-AS1 in PC.

RESULTS

CERS6-AS1 was significantly upregulated in PC. CERS6-AS1 silence obviously inhibited cell proliferation and migration in PC. Furthermore, CERS6-AS1 sponged microRNA-15a-5p (miR-15a-5p) and microRNA-6838-5p (miR-6838-5p) to regulate HMGA1. Moreover, rescue assays verified that CERS6-AS1 was involved in cell proliferation and migration in PC via targeting miR-15a-5p/miR-6838-5p/HMGA1 axis.

CONCLUSIONS

CERS6-AS1 enhanced HMGA1 expression to contribute to the progression of PC by sequestering miR-15a-5p and miR-6838-5p.

LINC01232 Sponges Multiple miRNAs and Its Clinical Significance in Pancreatic Adenocarcinoma Diagnosis and Prognosis

Background:

Long noncoding RNAs have been demonstrated to play important roles in different kinds of human malignancy. The purpose of this study was to evaluate the diagnostic and prognostic value of long intergenic non-protein coding RNA 1232 (LINC01232) in patients with pancreatic adenocarcinoma (PAAD) and further explore the clinical significance of the potential miRNAs that might be sponged by LINC01232.

Methods:

The potential target miRNAs that might be sponged by LINC01232 were analyzed using bioinformatics analysis. The Real-Time quantitative PCR was adopted to measure the relative expression of LINC01232 and target miRNAs in PAAD serum and tissue samples. The diagnostic and prognostic value of LINC01232 was evaluated using the receiver operating characteristic analysis and Kaplan-Meier survival analysis, respectively.

Results:

LINC01232 expression was upregulated in PAAD serum and tissues and associated with patients’ TNM stage. Serum LINC01232 expression had diagnostic value, and the high levels of LINC01232 could predict unfavorable prognosis in PAAD patients. miR-204-5p, miR-370-5p and miR-654-3p were proposed as 3 targets of LINC01232 in PAAD, and their decreased expression levels in PAAD patients showed certain clinical significance in diagnosis and prognosis.

Conclusion:

The data of this study revealed that LINC01232 expression is upregulated in PAAD serum and tissue samples with considerable diagnostic and prognostic significance. In addition, miR-204-5p, miR-370-5p and miR-654-3p may be sponged by LINC01232 in PAAD, which also show potencies in PAAD diagnosis and prognosis.

Exosomal long non-coding RNAs in the diagnosis and oncogenesis of pancreatic cancer

Extracellular vesicles, specifically exosomes, play a significant role as an extracellular messenger through their transporting cargo. Of particular interest are the potential roles they play in pancreatic cancer, one of the leading causes of cancer-related mortality worldwide. Pancreatic Ductal Adenocarcinoma displays high chemo-resistance and metastatic ability, which may be influenced by cancer-derived exosomes carrying proteins, lipids and RNA. To date, among the most extensively examined exosomal molecular cargo there are long non-coding RNAs (lncRNAs) that, despite the increasing interest in their role and functions, are relatively poorly understood compared to other RNA transcripts. Nevertheless, we have witnessed an increasing interest for lncRNAs roles and functions in the past decade. For example, lncRNAs have been investigated as potential biomarkers for diagnosing pancreatic cancer and may have a role as therapeutics targets for precision medicine, but may also directly intervene in tumour progression features such as metastasis, epithelial to mesenchymal transition and resistance of cancer cells towards chemotherapy agents. The function of lncRNAs within various cancer exosomes is still undefined. In this review, we summarize the current knowledge on pancreatic cancer-derived exosome specific lncRNAs having prominent roles in genome integrity, pancreatic cancer progression and in other oncogenic hallmarks.

Non-coding RNA biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.

Silencing of HIF-1α inhibited the expression of lncRNA NEAT1 to suppress development of hepatocellular carcinoma under hypoxia

BACKGROUND

We aimed to explore the relationship between hypoxia-inducible factors-1α (HIF-1α) and lncRNA nuclear-enriched abundant transcript 1 (NEAT1), and their functions on hepatocellular carcinoma (HCC) under hypoxia.

METHODS

HIF-1α and NEAT1 levels in HCC tissues and corresponding non-tumor tissues were determined by qRT-PCR, and the correlations of their levels in HCC tissues were analyzed by Pearson test. The relationship between overall survival and the two genes (HIF-1α and NEAT1) for HCC patients was detected by log-rank test. Clinicopathological features of NEAT1 in HCC patients were collected. HIF-1α and NEAT1 levels in HCC cells were measured by qRT-PCR and Western blot, and their relationship was determined by co-immunoprecipitation (Co-IP) assay. Cell viability, migration and invasion were detected by CCK-8, scratch wound healing and transwell assay, respectively. The interaction of NEAT1 with HIF-1α in tumor development was determined by xenograft tumor assays in nude mice.

RESULTS

NEAT1 and HIF-1α were highly expressed and showed a positive relationship in HCC tissues, and specifically, higher NEAT1 expression was positively associated with advanced TNM stage and metastasis in HCC patients. Up-regulated NEAT1 or HIF-1α in HCC patients had poorer prognosis. NEAT1 was induced by HIF-1α and suppressed by siHIF-1α. NEAT1 overexpression further promoted development of HCC under hypoxia while promoting cell viability, migration and invasion and suppressing apoptosis, and such effects were reversed by down-regulating HIF-1α. NEAT1 overexpression promoted tumor growth, which was reversed by down-regulating HIF-1α.

CONCLUSION

HIF-1α knockdown inhibits NEAT1 expression, which suppresses progression of HCC and improves its prognosis.

Exosome-transmitted long non-coding RNA SENP3-EIF4A1 suppresses the progression of hepatocellular carcinoma

Extracellular communication mediated by exosomes in a tumor microenvironment can substantially affect tumor progression. However, the effect of exosomal long non-coding RNA SENP3-EIF4A1 on hepatocellular carcinoma (HCC) is still unclear. In this study, SENP3-EIF4A1 expressions in patients with HCC and healthy controls were detected and compared. Results showed that SENP3-EIF4A1 was significantly reduced in HCC tissues and exosomes from the plasma of patients with HCC (P<0.05) and was primarily encapsulated by exosomes. The patients with HCC and the healthy controls could be distinguished using exosomal SENP3-EIF4A1 (AUC=0.8028). The transfer of exosomal SENP3-EIF4A1 secreted by normal cells to HCC cells stimulated apoptosis and weakened the invasion and migration abilities of HCC cells to suppress their malignant biological behavior (P<0.05). Additionally, exosomal SENP3-EIF4A1 was capable of inhibiting tumor growth in vivo and modulating the expression of ZFP36 by competitively binding to miR-9-5p. In conclusion, exosomal SENP3-EIF4A1 is a new favorable biomarker for clinically detecting HCC, and SENP3-EIF4A1 can be transmitted by exosomes from normal cells to HCC cells to inhibit the in vitro and in vivo development of HCC. Thus, exosomal SENP3-EIF4A1 is involved in the communication between normal cells and HCC cells during the onset of HCC.

LncRNA PVT1 promotes exosome secretion through YKT6, RAB7, and VAMP3 in pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest cancers worldwide. Cancer cells secrete excessive numbers of exosomes that play essential roles in tumorigenesis. Long non-coding RNAs (lncRNAs) are essential non-coding RNAs for cancer progression. However, the role of lncRNA plasmacytoma variant translocation 1 (PVT1) in exosome secretion of PC remains to be comprehensively investigated. Thus, nanoparticle tracking analysis and transmission electron microscopy were performed to determine exosome secretion. Confocal microscopy, western blots, real-time PCR, immunofluorescence, pull-down and RNA immunoprecipitation assays, and rescue experiments were applied to investigate the mechanism underlying the role of PVT1 in exosome secretion. The results showed that PVT1 was upregulated in PC cells, along with increased levels of YKT6 v-SNARE homolog (YKT6), ras-related protein Rab-7 (RAB7), and vesicle-associated membrane protein 3 (VAMP3). Also, PVT1 promoted the transportation of multivesicular bodies (MVBs) towards the plasma membrane. In addition, PVT1 promoted the docking of MVBs by altering RAB7 expression and localization. Moreover, PVT1 promoted the fusion of MVBs with the plasma membrane through regulating YKT6 and VAMP3 colocalization and the palmitoylation of YKT6. Taken together, the results suggest that PVT1 promoted exosome secretion of PC cells and thus, can expand the understanding of PVT1 in tumor biology.

LncRNA BANCR Promotes Pancreatic Cancer Tumorigenesis via Modulating MiR-195-5p/Wnt/β-Catenin Signaling Pathway

Long noncoding BRAF-activated noncoding RNA has been reported to be tightly associated with tumorigenesis and development in various types of cancers. However, the expression, biological function, and modulatory mechanism of BRAF-activated noncoding RNA in pancreatic cancer remained unclear. In the present work, we explored the carcinogenic activity and underlying mechanism of BRAF-activated noncoding RNA on pancreatic cancer in vitro. We identified that BRAF-activated noncoding RNA was upregulated in pancreatic cancer tissues and cell lines, and BRAF-activated noncoding RNA was related to tumor metastasis and stage. BRAF-activated noncoding RNA reinforces proliferation, invasion, and migration in PANC-1 and SW1990 cells. Moreover, miR-195-5p was downregulated in both PC tissues and cell lines. Our results based on luciferase reporter, RIP-Ago2 and qRT-PCR assays, showed that miR-195-5p was a direct target of BRAF-activated noncoding RNA. Furthermore, miR-195-5p inhibitor abrogated the effects of short-interfering BRAF-activated noncoding RNA on PANC-1 and SW1990 cell growth and invasion in vitro. We further identified that BRAF-activated noncoding RNA played a vital role in activating the Wnt/β-catenin pathway by sponging miR-195-5p. Collectively, our study showed that BRAF-activated noncoding RNA promotes pancreatic cancer tumorigenesis through miR-195-5p/Wnt/β-catenin axis may serve as a potential target for diagnostics and therapeutics in pancreatic cancer.

The lncRNA ENSG00000254041.1 promotes cell invasiveness and associates with poor prognosis of pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) mainly occurs after 60 years of age, and its prognosis remains poor despite modest improvements in recent decades. Long non-coding RNAs (lncRNAs) are well known as a class of transcripts involved in cancer occurrence and progression. The process of epithelial to a mesenchymal (EMT) phenotype in tumor cell increases their migratory and invasive properties, resulting in facilitating metastasis. Here, we reanalyzed RNA-seq data from the TCGA PC database and identified that ENSG00000254041.1 increasingly expressed in samples with elevated EMT signature score. Then, the evaluated expression and prognostic significance of ENSG00000254041.1 were verified in our cohort. Meanwhile, multivariate analysis suggested that ENSG00000254041.1 was independent factors for predicting the prognosis of PC, apart from advanced stage (III/IV). Moreover, functional assay revealed that knock down of ENSG00000254041.1 significantly decreased proliferation, invasion and chemoresistance of PC cells (SW1990 and BxPC-3), while overexpression of ENSG00000254041.1 in PC cells (Panc-1) resulted in the opposite effects. Western blot showed that knockdown of ENSG00000254041.1 expression in PC cells caused a significant downregulation of vimentin, Snail and SOX4, and upregulation of E-cadherin; also, ENSG00000254041.1 overexpression in PC cells resulted in opposite effects. In conclusion, these findings indicated that ENSG00000254041.1 promotes PC progression, and might provide a potential biomarker for predicting the prognosis of PC.

The multifaceted roles of long noncoding RNAs in pancreatic cancer: an update on what we know

Pancreatic cancer (PC) is one of the leading causes of cancer-related deaths worldwide. Due to the shortage of effective biomarkers for predicting survival and diagnosing PC, the underlying mechanism is still intensively investigated but poorly understood. Long noncoding RNAs (lncRNAs) provide biological functional diversity and complexity in protein regulatory networks. Scientific studies have revealed the emerging functions and regulatory roles of lncRNAs in PC behaviors. It is worth noting that some in-depth studies have revealed that lncRNAs are significantly associated with the initiation and progression of PC. As lncRNAs have good properties for both diagnostic and prognostic prediction due to their translation potential, we herein address the current understanding of the multifaceted roles of lncRNAs as regulators in the molecular mechanism of PC. We also discuss the possibility of using lncRNAs as survival biomarkers and their contributions to the development of targeted therapies based on the literature. The present review, based on what we know about current research findings, may help us better understand the roles of lncRNAs in PC.

Long noncoding RNA LINC01278 favors the progression of osteosarcoma via modulating miR-133a-3p/PTHR1 signaling

As one of the most aggressive malignancies, osteosarcoma has high risks of death. Although long noncoding RNAs (lncRNAs) may promote the osteosarcoma progression as verified, the potential molecular mechanism of lncRNAs in osteosarcoma remains unknown. Herein, we analyzed lncRNA microarray of osteosarcoma and selected LINC01278 as the study object. Then, we found that the expression of LINC01278 tested by quantitative reverse-transcription polymerase chain reaction was enhanced in tumor tissues compared with the para-carcinoma tissues and related to clinical stage, distant metastasis in osteosarcoma. In addition, the clinical outcomes were poor in osteosarcoma patients with high LINC01278 level. Moreover, LINC01278 promoted proliferation and restrained apoptosis in osteosarcoma cells. Afterward, mechanistic studies turned out that LINC01278 was a competing endogenous RNA of parathyroid hormone type 1 receptor (PTHR1) in osteosarcoma by sponging miR-133a-3p, which was considered as a tumor inhibitor in osteosarcoma. Furthermore, PTHR1 downregulation restored the impacts of inhibited miR-133a-3p on the processes in osteosarcoma cells. Our findings clarified that the carcinogenic effect of LINC01278 in osteosarcoma was mediated through miR-133a-3p/PTHR1 signaling, creating a novel insight into good targets for the therapy and prognosis of osteosarcoma.

Identify potential clinical significance of long noncoding RNA forkhead box P4 antisense RNA 1 in patients with early stage pancreatic ductal adenocarcinoma

Previous studies have shown that forkhead box P4 antisense RNA 1 (FOXP4‐AS1) is dysregulated in tumor tissues and can serve as a prognostic indicator for multiple cancers. However, the clinical significance of FOXP4‐AS1 in pancreatic ductal adenocarcinoma (PDAC) remains unclear. The goal of this study is to recognize the possible clinical significance of long noncoding RNA FOXP4‐AS1 in patients with early stage PDAC. A total of 112 patients from The Cancer Genome Atlas (TCGA) PDAC cohort, receiving RNA sequencing, were involved in the study. Survival analysis, functional mechanism, and potential small molecule drugs of target therapy of FOXP4‐AS1 were performed in this study. Survival analysis in TCGA PDAC cohort suggested that patients with high FOXP4‐AS1 expression had significantly augmented possibility of death than in PDAC patients with lower FOXP4‐AS1 expression (adjusted P = .008; adjusted HR = 2.143, 95% CI = 1.221‐3.760). In this study, a genome‐wide RNA sequencing dataset was used to identify 927 genes co‐expressing with FOXP4‐AS1 in PDAC tumor tissues. A total of 676 differentially expressed genes were identified between different FOXP4‐AS1 expression groups. Functional enrichment analysis of these genes and gene set enrichment analysis for PDAC genome‐wide RNA sequencing dataset was done. We have found that FOXP4‐AS1 may function in PDAC by participating in biological processes and pathways including oxidative phosphorylation, tricarboxylic acid cycle, classical tumor‐related pathways such as NF‐kappaB as well as Janus kinase/signal transducers in addition to activators of transcription, cell proliferation, and adhesion. In addition, we also screened two potential targeted therapeutic small molecule drugs (dimenhydrinate and metanephrine) for FOXP4‐AS1 in PDAC. In conclusion, our present study demonstrated that higher expression of FOXP4‐AS1 in PDAC tumor tissues were related with an inferior medical outcome. Through multiple genome‐wide approaches, we identified the potential molecular mechanisms of FOXP4‐AS1 in PDAC and two targeted therapeutic drugs for it.

Linc00261 inhibits metastasis and the WNT signaling pathway of pancreatic cancer by regulating a miR‑552‑5p/FOXO3 axis

The biological function of long non-coding RNA00261 (Linc00261) has been widely investigated in various types of cancer. The aim of the present study was to explore the role of Linc00261 in pancreatic cancer (PC). The expression of Linc00261 in patients with PC and PC cell lines was assessed using reverse transcription-quantitative PCR and the association of Linc00261 expression with survival was analyzed in the online database, GEPIA. The effects of Linc00261 on PC cell metastasis in vitro and in vivo were determined using a wound healing assay, Transwell invasion assays and a nude mouse model of liver metastasis. The relationship between Linc00261, the miR-552-5p/forkhead box O3 (FOXO3) axis and the Wnt signaling pathway were determined using bioinformatics analysis, dual luciferase assay and western blotting. Linc00261 expression was significantly decreased in PC tissues and cell lines, and reduced expression was associated with less favorable outcomes in patients with PC. Linc00261 overexpression inhibited migration and invasion of PC cells in vitro, whereas knockdown of Linc00261 increased migration and invasion. Linc00261 overexpression also decreased metastasis of PC cells in vivo. Linc00261 was revealed to directly bind to microRNA (miR)-552-5p and to decrease the expression of miR-552-5p. In addition, Linc00261 overexpression increased the expression of FOXO3, a target gene of miR-552-5p, as well as inhibited the Wnt signaling pathway. Overexpression of miR-552-5p in Linc00261-overexpressing PC cells increased migration and invasion, as well as decreased the expression of FOXO3 and members of the Wnt signaling pathway. Collectively, the present study demonstrated that Linc00261 inhibited metastasis and the Wnt signaling pathway of PC by regulating the miR-552-5p/FOXO3 axis. Linc00261 may suppress the development of PC, and serve as a potential biomarker and effective target for the diagnosis and treatment of PC.

LncRNAs in ocular neovascularizations

The prevalence of eye diseases worldwide is dramatically increasing and represents a major concern in underdeveloped and developed regions. Ocular diseases, previously associated with a higher depression risk, also impose a substantial economic burden on affected families, thus early detection and/or accurate treatment in order to avoid and prevent blindness should be emphasized. Ocular neovascularization (NV), the leading cause of blindness in a variety of eye diseases, is a pathologic process characterized by the formation, proliferation and infiltration of anomalous, tiny and leaky fragile blood vessels within the eye. Genetics have been suspected to play an important role in the occurrence of eye diseases, with the detection of a numbers of specific gene mutations. Long non-coding RNA (lncRNAs) are novel class of regulatory molecules previously associated with various biological processes and diseases, however the nature of the relation and pathways by which they might contribute to the development of corneal, choroidal and retinal NV have not yet been completely elucidated. In this review, we focus on the regulation and characteristics of lncRNAs, summarize results from ocular NV-related studies and discuss the implication of lncRNAs in ocular NV development.

Long non-coding RNA HULC as a diagnostic and prognostic marker of pancreatic cancer

BACKGROUND

Long non-coding RNA (lncRNA) is abnormally expressed in various malignant tumors. In recent years, it has been found that IncRNA HULC is increasingly expressed in pancreatic cancer tissues and is involved in the development and progression of pancreatic cancer. However, the clinical value of serum HULC in pancreatic cancer remains unclear, and there are few studies on how HULC regulates the biological function of pancreatic cancer cells.

AIM

To determine the value of lncRNA HULC in the diagnosis and prognosis of pancreatic cancer, and its possible biological potential.

METHODS

Sixty patients with pancreatic cancer and sixty patients with benign pancreatic diseases admitted to Xiangya Hospital, Central South University were assigned to the pancreatic cancer group and the benign disease group, respectively, and another 60 healthy subjects were enrolled as the normal group during the same period. HULC-siRNA and NC-siRNA were transfected into pancreatic cancer cells. Quantitative real-time polymerase chain reaction was performed to determine the expression of HULC in tissues, serum, and cells. Western Blot was carried out to determine the expression of β-catenin, c-myc, and cyclin D1 in cells, and the cell counting kit-8, flow cytometry, and Transwell assay were conducted to determine the proliferation, apoptosis and invasion of cells.

RESULTS

Highly expressed in the tissues and serum of pancreatic cancer patients, HULC showed good clinical value in distinguishing between patients with pancreatic cancer, patients with benign pancreatic diseases and healthy subjects. HULC was related to pathological parameters including tumor size, T staging, M staging and vascular invasion, and the area-under-the-curve for evaluating these four parameters was 0.844, 0.834, 0.928 and 0.818, respectively. Patients with low expression of HULC had a significantly higher 3-year overall survival (OS) and 5-year OS than those with high expression. T staging, M staging, vascular invasion, and HULC were independent prognostic factors affecting the 3-year OS of patients with pancreatic cancer. Inhibition of HULC expression prevented the proliferation and invasion of pancreatic cancer cells, promoted apoptosis, and inhibited the expression of Wnt/β-catenin signaling pathway-related proteins, β-catenin, c-myc, and cyclin D1. The Wnt/β-catenin signaling pathway agonist (LiCl) restored proliferation, apoptosis, and invasion of pancreatic cancer cells with inhibited expression of HULC.

CONCLUSION

HULC is an effective marker for the diagnosis and prognosis of pancreatic cancer, which may affect the biological function of pancreatic cancer cells through the Wnt/β-catenin signaling pathway.

Long non-coding SBF2-AS1 acting as a competing endogenous RNA to sponge microRNA-142-3p to participate in gemcitabine resistance in pancreatic cancer via upregulating TWF1

OBJECTIVE

This study is implemented to probe into the function of lncRNA SBF2-AS1 as a competing endogenous RNA (ceRNA) to sponge microRNA-142-3p (miR-142-3p) in modulating TWF1 expression in the gemcitabine resistance of pancreatic cancer.

RESULTS

LncRNA SBF2-AS1 was highly expressed in pancreatic cancer tissues and cells. SBF2-AS1 was found to be associated with gemcitabine resistance in pancreatic cancer. Knock-down of SBF2-AS1 inhibited proliferation, epithelial-mesenchymal transition, while promoting apoptosis of gemcitabine resistant pancreatic cancer cells. SBF2-AS1 inhibited the expression of TWF1 by competitively binding with miR-142-3p in pancreatic cancer.

CONCLUSION

Our study demonstrates that knock-down of SBF2-AS1 inhibits the expression of TWF1 by competitively binding with miR-142-3p to induce gemcitabine resistance in pancreatic cancer.

METHODS

Expression of SBF2-AS1 was tested in pancreatic cancer tissues and cells. Construction of AsPC-1/GEM and PANC-1/GEM cells with low expression of SBF2-AS1 was performed to determine the biological behaviors of drug-resistant cells. AsPC-1 and PANC-1 cells expressing SBF2-AS1 and/or miR-142-3p were constructed and treated with different concentrations of gemcitabine to detect the sensitivity of the cells to gemcitabine. The binding relationship between SBF2-AS1 and miR-142-3p and between miR-142-3p and TWF1 were determined.

Long non-coding RNA PXN-AS1 suppresses pancreatic cancer progression by acting as a competing endogenous RNA of miR-3064 to upregulate PIP4K2B expression

BACKGROUND

Dysregulation of microRNAs (miRNAs) play critical roles in cancerous processes. Although miR-3064 was reported to be an important tumor suppressor in ovarian cancer, the cellular impact of miR-3064 on pancreatic cancer (PC) progression, its downstream target genes and upstream mechanisms that control the expression of miR-3064 remain to be fully clarified.

METHODS

We compared miRNA expression profiles between PC tissues compared with normal tissues using a miRNA microarray analysis of clinical samples, and screened the identified miRNAs for their influence on cell proliferation. We measured the expression of miR-3064 in PC tissues and PC cell lines using quantitative real-time PCR assays. Gain- and loss-of-function experiments were conducted to explore the biologic significance of miR-3064 in PC progression both in vitro and in vivo. The interactions between miR-3064 and long noncoding RNA (lncRNA) PXN-AS1 was verified using the luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

We showed that miR-3064 was significantly overexpressed in PC tissues compared to normal tissues. High miR-3064 was associated with worse prognosis in patients with PC. Functionally, ectopic expression of miR-3064 promoted the proliferation, invasion, clone formation and sphere formation of PC cells in vitro and stimulated PC growth in vivo, while specific knockdown of miR-3064 or CRISPR/Cas9-mediated knockout of miR-3064 resulted in opposite phenotypes. Further investigation revealed that miR-3064 directly targeted PIP4K2B, which was reduced in PC tissues and attenuated PC cell proliferation, invasion and sphere formation induced by miR-3064. Importantly, lncRNA PXN-AS1 expression was downregulated in PC samples, and it directly interacted with miR-3064 and suppressed its levels in PC cells. Enforced expression of PXN-AS1 remarkably decreased cell proliferation, invasion and sphere formation, while re-expression of miR-3064 abrogated these effects of PXN-AS1.

CONCLUSIONS

MiR-3064, a key oncogenic miRNA, could promote PC cell growth, invasion and sphere formation via downregulating the levels of tumor suppressor PIP4K2B. PXN-AS1 functioned as a sponge to suppress the expression of miR-3064. These observations offer fresh insight into the mechanisms through which miR-3064 modulates the development of PC.