Long non-coding RNA LINC00346 promotes pancreatic cancer growth and gemcitabine resistance by sponging miR-188-3p to derepress BRD4 expression

Hsa_circ_0078767 Enhances Osteosarcoma Chemoresistance to Doxorubicin Through the Regulation of the miR-188-3p/GPX4 Axis

Background

Osteosarcoma (OS) is a primary malignancy of bone. The emergence of chemoresistance represents a persistent barrier to effective cancer patient care. This analysis sought to examine hsa_circ_0078767 as a mediator of doxorubicin (DOX) resistance in OS.

Methods

Levels of hsa_circ_0078767, miR-188-3p, and glutathione peroxidase 4 (GPX4) in OS clinical tissue samples and cell lines were evaluated by quantitative polymerase chain reaction (qPCR) and Western blotting. Associations between hsa_circ_0078767 levels in clinical samples and patient overall survival were assessed with Kaplan-Meier curves. CCK-8 assays were utilized as a means of examining DOX half-inhibitory concentration (IC50) values. RNA immunoprecipitation and pull-down, as well as reporter assays, investigated interactions between hsa_circ_0078767, miR-188-3p, and GPX4 within OS cells exhibiting DOX resistance.

Results

OS patient tissues and cell lines resistant to DOX exhibited elevated hsa_circ_0078767 and GPX4 expression together with a reduction in miR-188-3p levels. Inhibiting hsa_circ_0078767 expression contributed to a profound decrease in the ability of OS tumors to resist DOX. Mechanistically, it was determined that hsa_circ_0078767 can enhance DOX chemoresistance through its ability to bind and sequester miR-188-3p, which otherwise negatively modulates GPX4 to enhance chemosensitivity. Accordingly, the sequestration of miR-188-3p by hsa_circ_0078767 led to the derepression and upregulation of GPX4.

Conclusion

Hsa_circ_0078767 was found to modulate miR-188-3p/GPX4 signaling to enhance OS cell resistance to DOX treatment and facilitate disease progression. As such, hsa_circ_0078767 may represent a valuable biomarker or target for use in the context of OS patient management.

Ferroptosis-related LINC02535/has-miR-30c-5p/EIF2S1 axis as a novel prognostic biomarker involved in immune infiltration and progression of PDAC

BACKGROUND

PDAC, also known as pancreatic ductal adenocarcinoma, is often diagnosed at a late stage due to nonspecific symptoms and a distinct lack of reliable biomarkers for timely diagnosis. Ferroptosis, a novel non-apoptotic cell death mode discovered in recent years, is strongly linked to the progression of PDAC and the evasion of the immune system. The objective of this study is to discover a novel ceRNA biomarker associated with ferroptosis and investigate its possible molecular mechanisms and therapeutic potential in PDAC.

METHODS

Based on the FerrDb and TCGA databases, the R survival package was used to screen for ferroptosis-related mRNAs associated with PDAC prognosis. The ferroptosis-related ceRNA network was identified by miRTarBase, miRNet, and starBase and visualized using Cytoscape. The LASSO regression analysis was used to build a risk model associated with ceRNA. Additionally, we investigated the correlation between the ceRNA axis and the infiltration of immune cells in PDAC by employing the ssGSEA algorithm. Spearman correlation analysis was used to investigate the association between the ceRNA network and the expression levels of immune checkpoint genes in PDAC. The prediction of potential medications for PAAD patients with high risk scores was conducted using the R package oncoPredict and the Genomics of Drug Sensitivity in Cancer (GDSC) repository. Expression levels of LINC02535 in clinical specimens and PDAC cell lines were determined using qRT-PCR. CCK-8, colony formation, EdU, wound healing, and transwell assays were performed to assess the impact of reducing LINC02535 on the growth, migration, and invasion of PDAC cell lines BxPC3 and PANC1.

RESULTS

We first discovered a new LINC02535/miR-30c-5p/EIF2S1 axis associated with ferroptosis and created a prognostic nomogram for predicting overall survival. Meanwhile, the risk scores of the LINC02535/miR-30c-5p/EIF2S1 axis associated with ferroptosis were linked to immune subtypes in PDAC. The high immune infiltration subtype exhibited elevated ceRNA risk scores and EIF2S1 expression. The correlation analysis revealed a positive correlation between ceRNA risk scores and four immune cells, namely Activated CD4 T cell, Memory B cell, Neutrophil, and Type 2 T helper cell, as well as four immune checkpoint genes, namely CD274, HAVCR2, PDCD1LG2, and TIGIT. The analysis of drug sensitivity indicated that individuals with a high-risk score may exhibit greater sensitivity to inhibitors targeting MEK1/2 compared to those with a low-risk score. In our validation experiments, it was observed that the expression of LINC02535 was increased in both PDAC tissues and cell lines. Additionally, the inhibition of LINC02535 resulted in decreased proliferation, migration, and invasion of PDAC cells. Rescue experiments demonstrated that LINC02535 promoted PDAC cell growth and metastasis by upregulating EIF2S1 expression.

CONCLUSION

To summarize, a novel ferroptosis-associated LINC02535/miR-30c-5p/EIF2S1 ceRNA network for PDAC patients was established. The analysis of this network's functionality offers potential insights for clinical decision-making and the advancement of precision medicine.

Noncoding Ribonucleic Acids (RNAs) May Improve Response to Immunotherapy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the seventh most common cause of cancer-related mortality. Despite different methods of treatment, nearly more than 90% of patients with PDAC die shortly after diagnosis. Contrary to promising results in other cancers, immune checkpoint inhibitors (ICIs) showed limited success in PDAC. Recent studies have shown that noncoding RNAs (ncRNAs) are extensively involved in PDAC cell-immune cell interaction and mediate immune evasion in this vicious cancer. PDAC cells recruit numerous ncRNAs to widely affect the phenotype and function of immune cells through various mechanisms. For instance, PDAC cells upregulate miR-301a and downregulate miR-340 to induce M2 polarization of macrophages or overexpress miR-203, miR-146a, and miR-212-3p to downregulate toll-like receptor 4 (TLR4), CD80, CD86, CD1a, major histocompatibility complex (MHC) II, and CD83, thereby evading recognition by dendritic cells. By downregulating miR-4299 and miR-153, PDAC cells can decrease the expression of NK group 2D (NKG2D) and MHC class I chain-related molecules A and B (MICA/B) to blunt the natural killer (NK) cell response. PDAC cells also highly express lncRNA AL137789.1, hsa_circ_0046523, lncRNA LINC00460, and miR-155-5p to upregulate immune checkpoint proteins and escape T cell cytotoxicity. On the other hand, ncRNAs derived from suppressive immune cells promote proliferation, invasion, and drug resistance in PDAC cells. ncRNAs can be applied to overcome resistance to ICIs, monitor the immune microenvironment of PDAC, and predict response to ICIs. This Review article comprehensively discusses recent findings regarding the roles of ncRNAs in the immune evasion of PDAC.

The crosstalk between non-coding RNAs and cell-cycle events: A new frontier in cancer therapy

The cell cycle comprises sequential events during which a cell duplicates its genome and divides it into two daughter cells. This process is tightly regulated to ensure that the daughter cell receives identical copied chromosomal DNA and that any errors in the DNA during replication are correctly repaired. Cyclins and their enzyme partners, cyclin-dependent kinases (CDKs), are critical regulators of G- to M-phase transitions during the cell cycle. Mitogenic signals induce the formation of the cyclin/CDK complexes, resulting in phosphorylation and activation of the CDKs. Once activated, cyclin/CDK complexes phosphorylate specific substrates that drive the cell cycle forward. The sequential activation and inactivation of cyclin-CDK complexes are tightly controlled by activating and inactivating phosphorylation events induced by cell-cycle proteins. The non-coding RNAs (ncRNAs), which do not code for proteins, regulate cell-cycle proteins at the transcriptional and translational levels, thereby controlling their expression at different cell-cycle phases. Deregulation of ncRNAs can cause abnormal expression patterns of cell-cycle-regulating proteins, resulting in abnormalities in cell-cycle regulation and cancer development. This review explores how ncRNA dysregulation can disrupt cell division balance and discusses potential therapeutic approaches targeting these ncRNAs to control cell-cycle events in cancer treatment.

Regulation of inflammatory response by LINC00346 via miR-25-3p-mediated modulation of the PTEN/PI3K/AKT/NF-κB pathway

Long intergenic non-coding RNA 346 (LINC00346) has been reported to be involved in the development of atherosclerosis and specific cancers by affecting signaling pathways. However, its function in inflammation has not been thoroughly studied. Therefore, its expression pattern and function were determined in the human macrophage-like cell line THP-1. Lipopolysaccharide (LPS) treatment induced the expression of LINC00346. LPS-induced NF-κB activation and proinflammatory cytokine expression were suppressed or enhanced by the overexpression or knockdown of LINC00346, respectively. Analyses using dual luciferase assay and decoy RNAs that could block RNA-RNA interactions indicated that LINC00346 improves phosphatase and tensin homolog (PTEN) expression by sponging miR-25-3p. Subsequently, PTEN suppresses phosphoinositide-3 kinase (PI3K)-mediated conversion of phosphatidylinositol-4,5-bisphosphate (PIP2) into phosphatidylinositol-3,4,5-trisphosphate (PIP3) as well as consequent activation of protein kinase B (AKT) and NF-κB. Interestingly, database analysis revealed that the expression levels of LINC00346 and PTEN were simultaneously decreased in breast cancer tissues. Further analyses conducted using a breast cancer cell line, MDA-MB-231, confirmed the functional relationship among LINC00346, miR-25-3p, and PTEN in LPS-induced activation of NF-κB. These results indicate that miR-25-3p-sponging activity of LINC00346 affects the balance between PTEN and PI3K as well as the downstream activation of AKT/NF-κB pathway in inflammatory conditions.

Long non-coding RNAs and pancreatic cancer: A multifaceted view

Pancreatic cancer (PC) is a highly malignant disease with a 5-year survival rate of only 10%. Families with PC are at greater risk, as are type 2 diabetes, pancreatitis, and other factors. Insufficient early detection methods make this cancer have a poor prognosis. Additionally, the molecular mechanisms underlying PC development remain unclear. Increasing evidence suggests that long non-coding RNAs (lncRNAs) contribute to PC pathology,which may control gene expression by recruiting histone modification complexes to chromatin and interacting with proteins and RNAs. In recent studies, abnormal regulation of lncRNAs has been implicated in PC proliferation, metastasis, invasion, angiogenesis, apoptosis, and chemotherapy resistance suggesting potential clinical implications. The paper reviews the progress of lncRNA research in PC about diabetes mellitus, pancreatitis, cancer metastasis, tumor microenvironment regulation, and chemoresistance. Furthermore, lncRNAs may serve as potential therapeutic targets and biomarkers for PC diagnosis and prognosis. This will help improve PC patients' survival rate from a lncRNA perspective.

Antitumor activity of miR-188-3p in gastric cancer is achieved by targeting CBL expression and inactivating the AKT/mTOR signaling

BACKGROUND

Altered miR-188-3p expression has been observed in various human cancers.

AIM

To investigate the miR-188-3p expression, its roles, and underlying molecular events in gastric cancer.

METHODS

Fifty gastric cancer and paired normal tissues were collected to analyze miR-188-3p and CBL expression. Normal and gastric cancer cells were used to manipulate miR-188-3p and CBL expression through different assays. The relationship between miR-188-3p and CBL was predicted bioinformatically and confirmed using a luciferase gene reporter assay. A Kaplan-Meier analysis was used to associate miR-188-3p or CBL expression with patient survival. A nude mouse tumor cell xenograft assay was used to confirm the in vitro data.

RESULTS

MiR-188-3p was found to be lower in the plasma of gastric cancer patients, tissues, and cell lines compared to their healthy counterparts. It was associated with overall survival of gastric cancer patients (P < 0.001), tumor differentiation (P < 0.001), lymph node metastasis (P = 0.033), tumor node metastasis stage (I/II vs III/IV, P = 0.024), and American Joint Committee on Cancer stage (I/II vs III/IV, P = 0.03). Transfection with miR-188-3p mimics reduced tumor cell growth and invasion while inducing apoptosis and autophagy. CBL was identified as a direct target of miR-188-3p, with its expression antagonizing the effects of miR-188-3p on gastric cancer (GC) cell proliferation by inducing tumor cell apoptosis and autophagy through the inactivation of the Akt/mTOR signaling pathway. The in vivo data confirmed antitumor activity via CBL downregulation in gastric cancer.

CONCLUSION

The current data provides ex vivo, in vitro, and in vivo evidence that miR-188-3p acts as a tumor suppressor gene or possesses antitumor activity in GC.

Role of the long non-coding RNAs in regulation of Gemcitabine response in tumor cells

Chemotherapy is widely used as one of the first line therapeutic methods in cancer patients. However, chemotherapeutic resistance is one of the most common problems in cancer patients, which leads to the therapeutic failure and tumor relapse. Considering the side effects of chemotherapy drugs in normal tissues, it is required to investigate the molecular mechanisms involved in drug resistance to improve the therapeutic strategies in cancer patients. Long non-coding RNAs (lncRNAs) have pivotal roles in regulation of cellular processes associated with drug resistance. LncRNAs deregulations have been frequently reported in a wide range of chemo-resistant tumors. Gemcitabine (GEM) as a nucleoside analog has a wide therapeutic application in different cancers. However, GEM resistance is considered as a therapeutic challenge. Considering the role of lncRNAs in the occurrence of GEM resistance, in the present review we discussed the molecular mechanisms of lncRNAs in regulation of GEM response among cancer patients. It has been reported that lncRNAs have mainly an oncogenic role as the inducers of GEM resistance through direct or indirect regulation of transcription factors, autophagy, polycomb complex, and signaling pathways such as PI3K/AKT, MAPK, WNT, JAK/STAT, and TGF-β. This review paves the way to present the lncRNAs as non-invasive markers to predict GEM response in cancer patients. Therefore, lncRNAs can be introduced as the efficient markers to reduce the possible chemotherapeutic side effects in GEM resistant cancer patients and define a suitable therapeutic strategy among these patients.

Noncoding RNAs: an emerging modulator of drug resistance in pancreatic cancer

Pancreatic cancer is the eighth leading cause of cancer-related deaths worldwide. Chemotherapy including gemcitabine, 5-fluorouracil, adriamycin and cisplatin, immunotherapy with immune checkpoint inhibitors and targeted therapy have been demonstrated to significantly improve prognosis of pancreatic cancer patients with advanced diseases. However, most patients developed drug resistance to these therapeutic agents, which leading to shortened patient survival. The detailed molecular mechanisms contributing to pancreatic cancer drug resistance remain largely unclear. The growing evidences have shown that noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are involved in pancreatic cancer pathogenesis and development of drug resistance. In the present review, we systematically summarized the new insight on of various miRNAs, lncRNAs and circRNAs on drug resistance of pancreatic cancer. These results demonstrated that targeting the tumor-specific ncRNA may provide novel options for pancreatic cancer treatments.

Circular RNA circ0001955 promotes cervical cancer tumorigenesis and metastasis via the miR-188-3p/NCAPG2 axis

BACKGROUND

Circular RNAs (circRNAs) are known to play a crucial role in a variety of malignancies. However, the precise role of circRNAs in cervical squamous cell carcinoma (CSCC) remains largely unknown.

METHODS

The expression of circ0001955 was determined by real-time quantitative PCR and fluorescence in situ hybridization. To examine the effects of circ0001955 on CSCC metastasis and growth, functional experiments were conducted in vitro and in vivo. Mechanistically, nucleocytoplasmic separation, dual luciferase reporter assay, RNA antisense purification experiments, and rescue experiments were performed to confirm the interaction between circ0001955, miR-188-3p, and NCAPG2 in CSCC.

RESULTS

Here, we demonstrated that a circRNA derived from the CSNK1G1 gene (circ0001955) is significantly upregulated in CSCC. The overexpression of circ0001955 promotes tumor proliferation and metastasis, whereas the knockdown of circ0001955 exerts the opposite effects. Mechanistically, circ0001955 competitively binds miR-188-3p and prevents miR-188-3p from reducing the levels of NCAPG2, activating the AKT/mTOR signaling pathway to induce epithelial mesenchymal transformation. Notably, the application of an inhibitor of mTOR significantly antagonized circ0001955-mediated CSCC tumorigenesis.

CONCLUSION

circ0001955 promotes CSCC tumorigenesis and metastasis via the miR-188-3p/NCAPG2 axis which would provide an opportunity to search new therapeutic targets for CSCC.

Roles of lncRNAs in pancreatic ductal adenocarcinoma: Diagnosis, treatment, and the development of drug resistance

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers, primarily due to its late diagnosis, high propensity to metastasis, and the development of resistance to chemo-/radiotherapy. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) are intimately involved in the treatment resistance of pancreatic cancer cells via interacting with critical signaling pathways and may serve as potential diagnostic/prognostic markers or therapeutic targets in PDAC.

DATA SOURCES

We carried out a systematic review on lncRNAs-based research in the context of pancreatic cancer and presented an overview of the updated information regarding the molecular mechanisms underlying lncRNAs-modulated pancreatic cancer progression and drug resistance, together with their potential value in diagnosis, prognosis, and treatment of PDAC. Literature mining was performed in PubMed with the following keywords: long non-coding RNA, pancreatic ductal adenocarcinoma, pancreatic cancer up to January 2022. Publications relevant to the roles of lncRNAs in diagnosis, prognosis, drug resistance, and therapy of PDAC were collected and systematically reviewed.

RESULTS

LncRNAs, such as HOTAIR, HOTTIP, and PVT1, play essential roles in regulating pancreatic cancer cell proliferation, invasion, migration, and drug resistance, thus may serve as potential diagnostic/prognostic markers or therapeutic targets in PDAC. They participate in tumorigenesis mainly by targeting miRNAs, interacting with signaling molecules, and involving in the epithelial-mesenchymal transition process.

CONCLUSIONS

The functional lncRNAs play essential roles in pancreatic cancer cell proliferation, invasion, migration, and drug resistance and have potential values in diagnosis, prognostic prediction, and treatment of PDAC.

N6-methyladenosine-mediated SH3BP5-AS1 upregulation promotes GEM chemoresistance in pancreatic cancer by activating the Wnt signaling pathway

Background

Pancreatic cancer (PC) is highly malignant. Chemotherapy is the main treatment strategy, especially for patients with advanced PC. However, chemoresistance has always been a frequently encountered bottleneck. Hence, there is an urgent need to enhance the sensitivity of PC to gemcitabine (GEM).

Results

We demonstrated that SH3BP5-AS1 was significantly upregulated in GEM-resistant PC and predicted a poorer prognosis. SH3BP5-AS1 stability was regulated by ALKBH5/IGF2BP1-mediated m6A modification. Loss of SH3BP5-AS1 reduced PC cell migration and invasion and enhanced the sensitivity of PC to GEM, as confirmed by gain- and loss-of-function assays in vitro and in vivo. Bioinformatics analysis revealed that SH3BP5-AS1 acted as a ceRNA against miR-139-5p and directly targeted CTBP1, affecting the biological behavior of PC cells. The mechanistic studies revealed that the upregulation of SH3BP5-AS1 increased CTBP1 expression by directly activating the Wnt signaling pathway, promoting GEM resistance.

Conclusions

This study revealed that SH3BP5-AS1 activated Wnt signaling pathway by sponging miR-139-5p, upregulating CTBP1 expression, and contributing to the sensitivity of PC cells to GEM. SH3BP5-AS1 might be a potential target for PC therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13062-022-00347-5.

Emerging roles of long noncoding RNAs in chemoresistance of pancreatic cancer

Pancreatic cancer is one of the most common causes of cancer death in the world due to the lack of early symptoms, metastasis occurrence and chemoresistance. Therefore, early diagnosis by detection of biomarkers, blockade of metastasis, and overcoming chemoresistance are the effective strategies to improve the survival of pancreatic cancer patients. Accumulating evidence has revealed that long noncoding RNA (lncRNA) and circular RNAs (circRNAs) play essential roles in modulating chemosensitivity in pancreatic cancer. In this review article, we will summarize the role of lncRNAs in drug resistance of pancreatic cancer cells, including HOTTIP, HOTAIR, PVT1, linc-ROR, GAS5, UCA1, DYNC2H1-4, MEG3, TUG1, HOST2, HCP5, SLC7A11-AS1 and CASC2. We also highlight the function of circRNAs, such as circHIPK3 and circ_0000284, in regulation of drug sensitivity of pancreatic cancer cells. Moreover, we describe a number of compounds, including curcumin, genistein, resveratrol, quercetin, and salinomycin, which may modulate the expression of lncRNAs and enhance chemosensitivity in pancreatic cancers. Therefore, targeting specific lncRNAs and cicrRNAs could contribute to reverse chemoresistance of pancreatic cancer cells. We hope this review might stimulate the studies of lncRNAs and cicrRNAs, and develop the new therapeutic strategy via modulating these noncoding RNAs to promote chemosensitivity of pancreatic cancer cells.

The prognostic significance of bromodomain protein 4 expression in solid tumor patients: A meta-analysis

BACKGROUND

Cancer is a leading cause of death worldwide. At present, several inhibitors of bromodomain protein 4 have shown promising anti-tumor responses in clinical trials. Numerous studies have reported the value of bromodomain protein 4 expression in predicting the prognosis of patients with cancers, but their conclusions remain controversial. Therefore, we conducted a meta-analysis to explore the association between bromodomain protein 4 and patient prognosis with the aim to provide new directions for the development of strategies for targeted cancer therapy.

METHODS

The meta-analysis was registered in the International Prospective Register of Systematic Reviews (https://www.crd.york.ac.uk/prospero/; Registration No. CRD42020184948) and followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. PubMed Central, PubMed, Cochrane Library and Embase were thoroughly searched to identify eligible studies published through March 31, 2021. Odds ratios with 95% confidence intervals were calculated to demonstrate the relationship between bromodomain protein 4 expression and clinicopathological features. We computed pooled estimated hazard ratios with 95% confidence intervals using Stata 12.0 software to clarify the relationship between bromodomain protein 4 expression and overall survival of various cancers. A quality assessment of the eligible articles was performed based on the Newcastle-Ottawa scale.

RESULTS

A total of 974 patients from 10 studies were enrolled in the meta-analysis. Our results revealed that compared to low bromodomain protein 4 expression, high bromodomain protein 4 expression in cancer tissues was significantly associated with lymph node metastasis (Odds ratio = 3.59, 95% confidence interval: 2.62-4.91), distant metastasis (Odds ratio = 4.22, 95% confidence interval: 2.40-7.45), advanced TNM stage (III+IV vs. I+II: Odds ratio = 3.23, 95% confidence interval: 1.29-8.08), and poorly differentiated tumors (Odds ratio = 1.87, 95% confidence interval: 1.33-2.63). In addition, an elevated expression of bromodomain protein 4 tended to shorten survival time (Hazard ratio = 2.23, 95% confidence interval: 1.62-3.07). The subgroup analysis results showed that bromodomain protein 4 upregulation was related to poor prognosis in patients with digestive system cancers (Hazard ratio = 2.54, 95% confidence interval: 1.85-3.50).

CONCLUSION

This meta-analysis indicated that bromodomain protein 4 may serve as a promising prognostic biomarker for cancers and a direct effective cancer treatment target.

Long Non-Coding RNAs in Pancreatic Cancer: Biologic Functions, Mechanisms, and Clinical Significance

Despite tremendous efforts devoted to research in pancreatic cancer (PC), the mechanism underlying the tumorigenesis and progression of PC is still not completely clear. Additionally, ideal biomarkers and satisfactory therapeutic strategies for clinical application in PC are still lacking. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) might participate in the pathogenesis of diverse cancers, including PC. The abnormal expression of lncRNAs in PC is considered a vital factor during tumorigenesis that affects tumor cell proliferation, migration, invasion, apoptosis, angiogenesis, and drug resistance. With this review of relevant articles published in recent years, we aimed to summarize the biogenesis mechanism, classifications, and modes of action of lncRNAs and to review the functions and mechanisms of lncRNAs in PC. Additionally, the clinical significance of lncRNAs in PC was discussed. Finally, we pointed out the questions remaining from recent studies and anticipated that further investigations would address these gaps in knowledge in this field.

Potential roles of exosomal non-coding RNAs in chemoresistance in pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest digestive system tumors in the world, primarily attributed to difficulty in early diagnosis, early metastasis, and insen-sitivity to chemotherapy. The survival of advanced PC patients can be improved by chemotherapy, including gemcitabine, platinum drugs, and 5-fluorouracil, and targeted therapy such as PARP inhibitors. Nevertheless, primary or acquired drug resistance ultimately leads to treatment failure and poor prognosis in patients with PC. The mechanism underlying drug resistance in PC is complex and has not been fully elucidated. Recent studies have indicated that exsomes are the best natural carrier of non-coding RNAs (ncRNAs). They can regulate drug resistance by transporting ncRNAs. Accumulating evidence has demonstrated that exosomal ncRNAs, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), play an crucial role in regulating resistance to chemotherapy drugs in PC. In this review, we systematically focus on the emerging role and regulatory mechanisms of exosomal ncRNAs in influencing chemotherapy resistance in PC. We believe that exosomal ncRNAs can be considered as potential biomarkers for the diagnosis and prognosis of PC as well as new therapeutic targets.

Roles of lncRNAs Mediating Wnt/β-Catenin Signaling in HCC

Hepatocellular carcinoma (HCC) is considered the second most deadly cancer worldwide. Due to the absence of early diagnostic markers and effective therapeutic approaches, distant metastasis and increasing recurrence rates are major difficulties in the clinical treatment of HCC. Further understanding of its pathogenesis has become an urgent goal in HCC research. Recently, abnormal expression of long noncoding RNAs (lncRNAs) was identified as a vital regulator involved in the initiation and development of HCC. Activation of the Wnt/β-catenin pathway has been reported to obviously impact cell proliferation, invasion, and migration of HCC. This article reviews specific interactions, significant mechanisms and molecules related to HCC initiation and progression to provide promising strategies for treatment.

The Long Noncoding RNA LINC00963 Inhibits Corneal Fibrosis Scar Formation by Targeting miR-143-3p

Corneal fibrosis is a complication of severe corneal injury, one of the major causes of vision loss. The formation of myofibroblasts has emerged as a key stimulative factor of corneal fibrosis. In the current study, we focused on the role of LINC00963 in regulating corneal fibrosis. Transforming growth factor β1 (TGF-β1) was used to induce human corneal stromal cells differentiating into corneal myofibroblasts, and the significant increase of α-smooth muscle actin (α-SMA) was verified by quantitative real-time PCR (qRT-PCR), western blot, and immunofluorescence, respectively. LINC00963 was identified to be one-half decreased compared with nonstimulated human corneal stromal cells, indicating that it might play a role in corneal fibrosis. Interestingly, overexpression of LINC00963 resulted in decreased formation of myofibroblasts indicating that it might exhibit an inhibiting effect. Moreover, bioinformatics tool was applied to predict the downstream target of LINC00963. We investigated that LINC00963 suppressed α-SMA induced by TGF-β1 in corneal fibroblasts, at least in part, by downregulating the expression of miR-143-3p. In addition, either LINC00963 promotion or miR-143-3p inhibition could significantly decrease myofibroblast contractility and collagen I and III secretion, which are the key to contribute to corneal fibrosis. Taken together, our study identified LINC00963 as a promising therapeutic target.

New Insights into LINC00346 and its Role in Disease

Accumulating evidence has shown that long intergenic non-protein-coding RNA 346 (LINC00346) functions as an oncogene in the tumorigenesis of several cancers. The expression level of LINC00346 has been shown to be obviously correlated with prognosis, lymphoma metastasis, histological grade, TNM stage, tumor size and pathologic stage. LINC00346 has been found to regulate specific cellular functions by interacting with several molecules and signaling pathways. In this review, we summarize recent evidence concerning the role of LINC00346 in the occurrence and development of diseases. We also discuss the potential clinical utility of LINC00346, thereby providing new insight into the diagnosis and treatment of diseases. In addition, we further discuss the potential clinical utility of LINC00346 in the diagnosis, prognostication, and treatment of diseases.

Cardamonin Promotes the Apoptosis and Chemotherapy Sensitivity to Gemcitabine of Pancreatic Cancer Through Modulating the FOXO3a-FOXM1 Axis

Cardamonin (CAR), a flavone existing in the Alpinia plant, has been found to modulate multiple biological activities, including antioxidant, anti-inflammatory, and anti-tumor effects. Nevertheless, the influence of CAR on pancreatic cancer (PC) is less understood. Here, we conducted in vitro and in vivo experiments to explore the functions of CAR on PC cells’ proliferation, apoptosis and chemosensitivity to gemcitabine (GEM). The growth of PC cells (including PANC-1 and SW1990) was evaluated by the cell counting kit-8 assay, colony formation assay and xenograft tumor experiment. Besides, the apoptosis was determined by flow cytometry and western blot (WB). Moreover, the FOXO3a-FOXM1 pathway expression was tested by reverse transcription-polymerase chain reaction and WB. Our data suggested that CAR restrained cell proliferation, growth and expedited apoptosis both in vitro and in vivo. Moreover, CAR sensitized PC cells to GEM. Mechanistically, CAR heightened FOXO3a while repressed FOXM1. Further loss-of-function assays revealed that down-regulating FOXO3a markedly dampened the anti-tumor effect induced by CAR and accelerated the FOXM1 expression. Our data confirmed that CAR exerted an anti-tumor function in PC dependently by modulating the FOXO3a-FOXM1 axis.

The Long Non-Coding BC200 Is a Novel Circulating Biomarker of Parathyroid Carcinoma

Long non-coding RNAs (lncRNAs) are an important class of epigenetic regulators involved in both physiological processes and cancer development. Preliminary evidence suggested that lncRNAs could act as accurate prognostic and diagnostic biomarkers. Parathyroid cancer is a rare endocrine neoplasia, whose management represents a clinical challenge due to the lack of accurate molecular biomarkers. Our previous findings showed that human parathyroid tumors are characterized by a different lncRNAs signature, suggesting heterogeneity through the different histotypes. Particularly, we found that the lncRNA BC200/BCYRN1 could represent a candidate biomarker for parathyroid carcinomas (PCas). Here we aimed to extend our preliminary data evaluating whether BC200 could be an accurate non-invasive biomarker of PCas to support the clinical management of patients affected by parathyroid tumors at diagnosis, prognosis and follow-up. To provide a non-invasive point-of-care for parathyroid carcinoma diagnosis and follow-up, we analyzed BC200 expression in patients' serum through digital PCR. Our results show that BC200 counts are higher in serum from patients harboring PCa (n=4) compared to patients with parathyroid adenoma (PAd; n=27). Further, in PAd patients circulating BC200 levels are positively correlated with serum total calcium. Then, we found that BC200 is overexpressed in metastatic PCas (n=4) compared to non-metastatic ones (n=9). Finally, the lncRNA expression in PCa patients' serum drops are reduced after parathyroidectomy, suggesting its possible use in the post-operative setting for patients follow-up. Overall, these findings extend the knowledge on BC200 in parathyroid tumors, supporting its role as a useful biomarker for management of PCa.

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

Long Non-Coding RNAs in Epithelial-Mesenchymal Transition of Pancreatic Cancer

Non-coding RNAs (ncRNAs), or RNA molecules that do not code for proteins, are generally categorized as either small or long ncRNA (lncRNA) and are involved in the pathogenesis of several diseases including many cancers. Identification of a large number of ncRNAs could help to elucidate previously unknown mechanisms in phenotype regulation. Some ncRNAs are encapsulated by extracellular vesicles (EVs) and transferred to recipient cells to regulate cellular processes, including epigenetic and post-transcriptional regulations. Recent studies have uncovered novel molecular mechanisms and functions of lncRNAs in pancreatic ductal adenocarcinoma (PDAC), one of the most intractable cancers that is highly invasive and metastatic. As the epithelial-mesenchymal transition (EMT) triggers tumor cell invasion and migration, clarification of the roles of lncRNA in EMT and tumor cell stemness would be critical for improving diagnostic and therapeutic approaches in metastatic cancers. This review provides an overview of relevant studies on lncRNA and its involvement with EMT in PDAC. Emerging knowledge offers evidence for the dysregulated expression of lncRNAs and essential insights into the potential contribution of both lncRNAs and EVs in the pathogenesis of PDAC. Future directions and new clinical applications for PDAC are also discussed.

LncRNA HIF1A-AS1 Promotes Gemcitabine Resistance of Pancreatic Cancer by Enhancing Glycolysis through Modulating the AKT/YB1/HIF1α Pathway

Gemcitabine (GEM) resistance is a major challenge for chemotherapy of pancreatic cancer. Previous studies have reported on the role of long noncoding RNA (lncRNA) in tumorigenesis of pancreatic cancer, however, the involvement of lncRNA in the development of GEM resistance of pancreatic cancer remains unclear. In the present study, we demonstrated that the antisense RNA1 of HIF1α (HIF1A-AS1) was significantly elevated in the GEM-resistant pancreatic cancer cells. Gain- and lost-of-function experiments validated that HIF1A-AS1 promoted GEM resistance of pancreatic cancer cells both in vitro and vivo. We further revealed that HIF1A-AS1 upregulated HIF1α expression and thus promoted glycolysis to enhance GEM resistance of pancreatic cancer cells. Mechanistically, HIF1A-AS1 facilitated the interaction between serine/threonine kinase AKT and Y-box-binding protein 1 (YB1), which promoted phosphorylation of YB1 (pYB1). Meanwhile, HIF1A-AS1 recruited pYB1 to HIF1α mRNA that consequently promoted translation of HIF1α. Furthermore, HIF1α promoted HIF1A-AS1 transcription by directly binding to the HIF1α response element in the promoter area of HIF1A-AS1 to form a positive feedback. Consistently, both HIF1A-AS1 and HIF1α were upregulated in pancreatic cancer tissues and associated with poor overall survival. Together, our results underline a reciprocal loop of HIF1A-AS1 and HIF1α that contributes to GEM resistance of pancreatic cancer and indicate that HIF1A-AS1 might serve as a novel therapeutic target for GEM resistance of pancreatic cancer. SIGNIFICANCE: These findings show that a reciprocal feedback of HIF1A-AS1 and HIF1α promotes gemcitabine resistance of pancreatic cancer, which provides an applicable therapeutic target.

NR2F1-AS1 Promotes Pancreatic Ductal Adenocarcinoma Progression Through Competing Endogenous RNA Regulatory Network Constructed by Sponging miRNA-146a-5p/miRNA-877-5p

The role of NR2F1-AS1 in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Therefore, we aimed to investigate the biological mechanism of NR2F1-AS1 in PDAC. The expression of NR2F1-AS1 was measured by using microarray data and real-time PCR. The effects of NR2F1-AS1 knockdown on proliferation, cell cycle progression, invasion in vitro and tumorigenesis in vivo were investigated. The mechanism of competitive endogenous RNAs was determined from bioinformatics analyses and validated by a dual-luciferase reporter gene assay. Potential target mRNAs from TargetScan 7.2 were selected for subsequent bioinformatics analysis. Key target mRNAs were further identified by screening hub genes and coexpressed protein-coding genes (CEGs) of NR2F1-AS1. NR2F1-AS1 was highly expressed in PDAC, and the overexpression of NR2F1-AS1 was associated with overall survival and disease-free survival. The knockdown of NR2F1-AS1 impaired PDAC cell proliferation, migration, invasion and tumorigenesis. NR2F1-AS1 competitively sponged miR-146a-5p and miR-877-5p, and low expression of the two miRNAs was associated with a poor prognosis. An integrative expression and survival analysis of the hub genes and CEGs demonstrated that the NR2F1-AS1–miR-146a-5p/miR-877-5p–GALNT10/ZNF532/SLC39A1/PGK1/LCO3A1/NRP2/LPCAT2/PSMA4 and CLTC ceRNA networks were linked to the prognosis of PDAC. In conclusion, NR2F1-AS1 overexpression was significantly associated with poor prognosis. NR2F1-AS1 functions as an endogenous RNA to construct a novel ceRNA network by competitively binding to miR-146a-5p/miR-877-5p, which may contribute to PDAC pathogenesis and could represent a promising diagnostic biomarker or potential novel therapeutic target in PDAC.

LINC00346 Sponges miR-30c-2-3p to Promote the Development of Lung Adenocarcinoma by Targeting MYBL2 and Regulating CELL CYCLE Signaling Pathway

Background

LINC00346 has recently been reported to regulate the development of several cancer types, but its biological functions and underlying mechanisms in lung adenocarcinoma (LUAD) have not been elucidated. The purpose of this study was to investigate the molecular mechanism of LINC00346 in the progression of LUAD.

Methods

Bioinformatics was performed to find the target lncRNA, miRNA and mRNA, and the binding relationship between the target genes was verified by dual luciferase reporter gene and RIP assays. Fluorescence in situ hybridization was used to detect the location of LINC00346 in LUAD tissues. The expressions of LINC00346, miR-30c-2-3p and MYBL2 in each group were detected by qRT-PCR, and western blot was performed to detect expressions of MYBL2 and CELL CYCLE related proteins. Proliferation, metastasis, apoptosis and cell cycle of LUAD cells were detected by CCK-8, colony formation, Transwell and flow cytometry assays, respectively. Mouse xenograft models were established to further determine the effects of LINC00346 on LUAD tumor growth in vivo.

Results

LINC00346 was upregulated in LUAD tissues and cells and was mainly localized in the cytoplasm. Knockdown of LINC00346 inhibited tumor growth in vivo, proliferation, metastasis and cell cycle progression, while induced apoptosis. LINC00346 sponged miR-30c-2-3 by targeting MYBL2 and regulating CELL CYCLE signaling pathway. Inhibiting miR-30c-2-3p or overexpressing MYBL2 could reverse the inhibitory effect of LINC00346 knockdown on LUAD process.

Conclusions

LINC00346 as a ceRNA played a carcinogenic role in the development of LUAD via miR-30c-2-3p/MYBL2 axis regulating the CELL CYCLE signaling pathway. The study generally elucidated the mechanism by which LINC00346 regulated the development of LUAD, providing new ideas for the diagnosis and treatment of LUAD guided by lncRNA.

The Functions of BET Proteins in Gene Transcription of Biology and Diseases

The BET (bromodomain and extra-terminal domain) family proteins, consisting of BRD2, BRD3, BRD4, and testis-specific BRDT, are widely acknowledged as major transcriptional regulators in biology. They are characterized by two tandem bromodomains (BDs) that bind to lysine-acetylated histones and transcription factors, recruit transcription factors and coactivators to target gene sites, and activate RNA polymerase II machinery for transcriptional elongation. Pharmacological inhibition of BET proteins with BD inhibitors has been shown as a promising therapeutic strategy for the treatment of many human diseases including cancer and inflammatory disorders. The recent advances in bromodomain protein biology have further uncovered the complex and versatile functions of BET proteins in the regulation of gene expression in chromatin. In this review article, we highlight our current understanding of BET proteins' functions in mediating protein-protein interactions required for chromatin-templated gene transcription and splicing, chromatin remodeling, DNA replication, and DNA damage repair. We further discuss context-dependent activator vs. repressor functions of individual BET proteins, isoforms, and bromodomains that may be harnessed for future development of BET bromodomain inhibitors as emerging epigenetic therapies for cancer and inflammatory disorders.

Downregulation of NEAT1 sensitizes gemcitabine-resistant pancreatic cancer cells to gemcitabine through modulation of the miR-506-3p/ZEB2/EMT axis

Chemoresistance is a major cause of treatment failure in pancreatic cancer (PC). It has been demonstrated that epithelial-to-mesenchymal transition (EMT) is closely related to drug resistance in PC; however, the underlying mechanisms are not yet fully understood. Recently found evidence has suggested that nuclear-enriched abundant transcript 1 (NEAT1) is involved in the development of chemoresistance. However, the role and mechanism of NEAT1 in PC gemcitabine resistance remain unknown. In the present study, we first established two independent gemcitabine-resistant (GR) PC cell lines, PANC-1/GR and SW1990/GR. We found that GR cells displayed markedly enhanced migration and invasion abilities, decreased expression of E-cadherin, and upregulation of N-cadherin, Vimentin, Snail, ZEB1, and ZEB2. Our findings suggested that downregulation of NEAT1 enhanced the sensitivity of GR cells to gemcitabine by reversing the EMT process. Mechanistically, NEAT1 mediates ZEB2 mRNA expression through sponging miR-506-3p. Downregulation of NEAT1 can reverse the EMT process of GR PC cells by reducing the expression of ZEB2, thus enhancing the sensitivity of GR PC cells to gemcitabine. These findings were further confirmed in a nude mouse xenograft model. Taken together, downregulation of NEAT1 sensitized the GR PC cells to gemcitabine through modulation of the miR-506-3p/ZEB2/EMT axis. These results provide the novel evidence for understanding the function and molecular mechanism of NEAT1, and a new direction for improving the chemotherapeutic effects in PC.

Long non-coding RNA RP11-283G6.5 confines breast cancer development through modulating miR-188-3p/TMED3/Wnt/β-catenin signalling

The contributions of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) to breast cancer are critical areas of investigation. In this study, we identified a novel lncRNA RP11-283G6.5 which was lowly expressed in breast cancer and whose low expression was correlated with poor overall survival and disease-free survival of breast cancer patients. Functional experiments revealed that ectopic expression of RP11-283G6.5 confined breast cancer cellular growth, migration, and invasion, and promoted cellular apoptosis. Conversely, RP11-283G6.5 silencing facilitated breast cancer cellular growth, migration, and invasion, and repressed cellular apoptosis. Moreover, RP11-283G6.5 was found to confine breast cancer tumour growth and metastasis in vivo. Mechanistically, RP11-283G6.5 competitively bound to ILF3, reduced the binding of ILF3to primary miR-188 (pri-miR-188), abolished the suppressive effect of ILF3 on pri-miR-188 processing, and therefore promoted pri-miR-188 processing, leading to the reduction of pri-miR-188 and the upregulation of mature miR-188-3p. The expression of RP11-283G6.5 was significantly positively correlated with that of miR-188-3p in breast cancer tissues. Through increasing miR-188-3p, RP11-283G6.5 decreased TMED3, a target of miR-188-3p. RP11-283G6.5 further suppressed Wnt/β-catenin signalling via decreasing TMED3. Rescue assays revealed that inhibition of miR-188-3p, overexpression of TMED3 or blocking Wnt/β-catenin signalling all attenuated the roles of RP11-283G6.5 in breast cancer. Collectively, these findings demonstrated that RP11-283G6.5 is a tumour suppressive lncRNA in breast cancer via modulating miR-188-3p/TMED3/Wnt/β-catenin signalling. This study indicated that RP11-283G6.5 might be a promising prognostic biomarker and therapeutic target for breast cancer.

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.

Super-enhancers: a new frontier for epigenetic modifiers in cancer chemoresistance

Although new developments of surgery, chemotherapy, radiotherapy, and immunotherapy treatments for cancer have improved patient survival, the emergence of chemoresistance in cancer has significant impacts on treatment effects. The development of chemoresistance involves several polygenic, progressive mechanisms at the molecular and cellular levels, as well as both genetic and epigenetic heterogeneities. Chemotherapeutics induce epigenetic reprogramming in cancer cells, converting a transient transcriptional state into a stably resistant one. Super-enhancers (SEs) are central to the maintenance of identity of cancer cells and promote SE-driven-oncogenic transcriptions to which cancer cells become highly addicted. This dependence on SE-driven transcription to maintain chemoresistance offers an Achilles' heel for chemoresistance. Indeed, the inhibition of SE components dampens oncogenic transcription and inhibits tumor growth to ultimately achieve combined sensitization and reverse the effects of drug resistance. No reviews have been published on SE-related mechanisms in the cancer chemoresistance. In this review, we investigated the structure, function, and regulation of chemoresistance-related SEs and their contributions to the chemotherapy via regulation of the formation of cancer stem cells, cellular plasticity, the microenvironment, genes associated with chemoresistance, noncoding RNAs, and tumor immunity. The discovery of these mechanisms may aid in the development of new drugs to improve the sensitivity and specificity of cancer cells to chemotherapy drugs.

Long noncoding RNA (lncRNA) EIF3J-DT induces chemoresistance of gastric cancer via autophagy activation

Chemotherapy is currently the main treatment for unresectable or advanced postoperative gastric cancers. However, its efficacy is negatively affected by the occurrence of chemoresistance, which severely affects patient prognosis. Recently, dysregulation in autophagy has been suggested as a potential mechanism for chemoresistence, and long noncoding RNA (lncRNA) also shows its regulatory role in cancer drug resistance. Using RNA sequencing, we found that lncRNA EIF3J-DT was highly expressed in drug-resistant gastric cancer cells. In-vitro and in-vivo experiments showed that EIF3J-DT activated autophagy and induced drug resistance in gastric cancer cells by targeting ATG14. Bioinformatics and experimental results showed that EIF3J-DT regulated the expression of ATG14 through direct binding to enhance stabilization of ATG14 mRNA and via blocking the degradation of ATG14 mRNA through competitively binding with microRNA (miRNA) MIR188-3p. Therefore, EIF3J-DT increased the expression of ATG14, contributing to activation of autophagy and chemoresistance. Furthermore, it was confirmed that EIF3J-DT and ATG14 were highly expressed in gastric cancer patients resistant to chemotherapy, and this was closely associated with patient prognosis. In conclusion, EIF3J-DT is involved in the regulation of autophagy and chemoresistance in gastric cancer cells by targeting ATG14. It may be a suitable new target for enhancing chemosensitivity and improving prognosis.Abbreviations: 3-MA: 3-methyladenine; 5-Fu: 5-fluorouracil; ATG: autophagy related; C-CASP3: cleaved caspase 3; C-CASP7: cleaved caspase 7; C-PARP: cleaved PARP; CQ: chloroquine; CR: complete response; DIG: digoxigenin; ESR1: estrogen receptor 1; FBS: fetal bovine serum; FISH: fluorescence in situ hybridization; IHC: immunohistochemistry; ISH: in situ hybridization; lncRNA: long noncoding RNA; miRNA: microRNA; MUT: mutant; NC: negative control; OXA: oxaliplatin; PBS: phosphate-buffered saline; PD: progressive disease; PFA: paraformaldehyde; PR: partial response; qPCR: quantitative polymerase chain reaction; RAPA: rapamycin; SD: stable disease; TEM: transmission electron microscopy; WT: wild type.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

Long noncoding RNA LINC00941 promotes pancreatic cancer progression by competitively binding miR-335-5p to regulate ROCK1-mediated LIMK1/Cofilin-1 signaling

An accumulation of evidence indicates that long noncoding RNAs are involved in the tumorigenesis and progression of pancreatic cancer (PC). In this study, we investigated the functions and molecular mechanism of action of LINC00941 in PC. Quantitative PCR was used to examine the expression of LINC00941 and miR-335-5p in PC tissues and cell lines, and to investigate the correlation between LINC00941 expression and clinicopathological features. Plasmid vectors or lentiviruses were used to manipulate the expression of LINC00941, miR-335-5p, and ROCK1 in PC cell lines. Gain or loss-of-function assays and mechanistic assays were employed to verify the roles of LINC00941, miR-335-5p, and ROCK1 in PC cell growth and metastasis, both in vivo and in vitro. LINC00941 and ROCK1 were found to be highly expressed in PC, while miR-335-5p exhibited low expression. High LINC00941 expression was strongly associated with larger tumor size, lymph node metastasis, and poor prognosis. Functional experiments revealed that LINC00941 silencing significantly suppressed PC cell growth, metastasis and epithelial–mesenchymal transition. LINC00941 functioned as a molecular sponge for miR-335-5p, and a competitive endogenous RNA (ceRNA) for ROCK1, promoting ROCK1 upregulation, and LIMK1/Cofilin-1 pathway activation. Our observations lead us to conclude that LINC00941 functions as an oncogene in PC progression, behaving as a ceRNA for miR-335-5p binding. LINC00941 may therefore have potential utility as a diagnostic and treatment target in this disease.

B3GNT3 overexpression promotes tumor progression and inhibits infiltration of CD8+ T cells in pancreatic cancer

Beta-1,3-N-acetylglucosaminyltransferase 3 (B3GNT3) has been associated with tumor progression in several solid tumors, and inhibits CD8⁺ T cell-mediated anti-tumor immunity in breast cancer. However, little is known about the potential functions of B3GNT3 in immunosuppression in pancreatic cancer (PC). This study on B3GNT3 aims to provide novel insights into the mechanisms of immune suppression or evasion in PC. To this end, the clinical significance and oncologic roles of B3GNT3 were investigated through bioinformatic analysis and in vitro studies. Potential associations between the expression of B3GNT3 and tumor immunity were mainly analyzed by single-sample gene set enrichment analysis (ssGSEA) and immunofluorescence in tissue microarray (TMA). B3GNT3 overexpression was observed in PC tissue and was associated with larger tumor sizes, higher histologic grades, and poorer overall survival (OS). B3GNT3 overexpression was associated with the mutation status and expression of driver genes, especially for KRAS and SMAD4. B3GNT3 knockdown inhibited the proliferation, invasion, and epithelial-mesenchymal transition (EMT) of PC cells. B3GNT3 overexpression significantly correlated with decreased infiltration of tumor infiltrating lymphocytes (TILs), especially CD8⁺ T cells. Overall, our results indicate that B3GTN3 plays a novel role in tumor progression and immunosuppression, thus serving as a potential therapeutic target in PC.

Noncoding RNAs in drug-resistant pancreatic cancer: A review

Pancreatic cancer is the fourth-leading cause of cancer-related deaths and is expected to be the second-leading cause of cancer-related deaths in Europe and the United States by 2030. The high fatality rate of pancreatic cancer is ascribed to untimely diagnosis, early metastasis and limited responses to both chemotherapy and radiotherapy. Although gemcitabine, 5-fluorouracil and some other drugs can profoundly improve patient prognosis, most pancreatic cancer patients eventually develop drug resistance, leading to poor clinical outcomes. The underlying mechanisms of pancreatic cancer drug resistance are complicated and inconclusive. Interestingly, accumulating evidence has demonstrated that different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play a crucial role in pancreatic cancer resistance to chemotherapy reagents. In this paper, we systematically summarize the molecular mechanism underlying the influence of ncRNAs on the generation and development of drug resistance in pancreatic cancer and discuss the potential role of ncRNAs as prognostic markers and new therapeutic targets for pancreatic cancer.

Long noncoding RNA LINC00460 promotes the progression of cervical cancer via regulation of the miR-361-3p/Gli1 axis

Mounting evidence indicates that the long non-coding RNA (lncRNA) LINC00460 plays an oncogenic role in tumor progression; however, the role of LINC00460 in cervical cancer (CC) remains unknown. In this study, we found that LINC00460 was frequently upregulated in CC tissues and cell lines. Knockdown of LINC00460 repressed CC cell growth and invasion in vitro and attenuated tumorigenesis in vivo. Mechanistically, miR-361-3p was predicted as a direct target of LINC00460 by bioinformatics analysis, which was further confirmed by qRT-PCR, dual-luciferase reporter assays, and rescue experiments. Furthermore, miR-361-3p targeted the 3' untranslated region (UTR) of Gli1 mRNA and repressed its expression. Taken together, our study revealed that LINC00460 functions as an oncogenic lncRNA in CC, indicating the likely participation of the LINC00460/miR-361-3p/Gli1 pathway in the disease. Accordingly, our results provide new insight into CC tumorigenesis.

miR-188-3p Inhibits Vascular Smooth Muscle Cell Proliferation and Migration by Targeting Fibroblast Growth Factor 1 (FGF1)

Background

As one of the crucial causes leading to cardiovascular disease, atherosclerosis (AS) develops in association with the dysfunction of vascular smooth muscle cells (VSMCs). However, the associated mechanism of the proliferation and migration in VSMCs requires further elucidation.

Material/Methods

Human VSMCs and ApoE-knockout (ApoE^−/−) mice were used to establish AS cell and animal models, respectively. Expression levels of miR-188-3p and fibroblast growth factor 1 (FGF1) mRNA were detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blot was used to assess FGF1 protein expression. The proliferation, migration, and apoptosis of the cells were determined using MTT, BrdU, and Transwell assays, as well as flow cytometry analysis. The interaction between miR-188-3p and FGF1 was validated using dual-luciferase reporter gene assay, qRT-PCR, and Western blot analysis.

Results

MiR-188-3p was found to be significantly decreased in the serum of AS patients and ApoE^−/− mice as well as VSMCs of ApoE^−/− mice and human VSMCs treated with oxidized low-density lipoprotein. MiR-188-3p repressed the proliferation and migration of VSMCs but promoted apoptosis of VSMCs. The binding site between miR-188-3p and 3′ untranslated region (3′-UTR) of FGF1 was identified, and FGF1 was verified as a target gene of miR-188-3p. Restoration of FGF1 reversed the effects of miR-188-3p on VSMCs.

Conclusions

MiR-188-3p suppresses the proliferation and migration of VSMCs and induces their apoptosis through targeting FGF1.

Long noncoding RNA LINC00346 promotes glioma cell migration, invasion and proliferation by up-regulating ROCK1

Long noncoding RNAs have key roles in glioma progression. However, the function and mechanisms of action of the long noncoding RNA, LINC00346, in glioma remain unclear. In our study, we observed that LINC00346 levels were increased in glioma tissue samples, and according to Gene Expression Profiling Interactive Analysis, its levels were related to disease‐free survival and overall survival rates, suggesting that a high level of LINC00346 expression corresponds to a poor prognosis. We next confirmed the high levels of LINC00346 expression in glioma tissues and cell lines and showed that LINC00346 knockdown suppressed glioma cell proliferation, migration and invasion; promoted apoptosis; and delayed tumour growth. Moreover, the oncogenic function of LINC00346 may be explained, in part, by the down‐regulation of miR‐340‐5p and the de‐repression of ROCK1. We showed that LINC00346 may function as a competing endogenous RNA of miR‐340‐5p, thereby de‐repressing ROCK1. This study revealed a new regulatory network in glioma and identified potential therapeutic targets for this cancer.

The implication of long non-coding RNAs in the diagnosis, pathogenesis and drug resistance of pancreatic ductal adenocarcinoma and their possible therapeutic potential

Pancreatic ductal adenocarcinoma (PDAC) is one of the lethal malignancies with the lowest median and overall survival rate among all human malignancies. The major problems with the PDAC are the late diagnosis, metastasis, and acquired resistance to chemotherapeutic agents in the clinic. Over the last decade, the long non-coding RNAs (lncRNAs) have been discovered and occupies a significantly large proportion of the human genome. Recent studies have proved that lncRNAs can play a crucial role in the majority of key cellular processes involved in the maintenance of cellular homeostasis by regulating various molecular mechanisms. The deregulation of lncRNAs has been associated with various chronic diseases including human malignancies. Several lncRNAs have tumor-specific expression making them an ideal and excellent target for designing the novel therapeutic strategies against human malignancies. We have discussed how lncRNA expression can be used for the diagnosis and prognosis of PDAC. The current review discusses the potential role and molecular mechanism of lncRNA in regulating the prominent hallmarks of cancer including abnormal growth, survival, metastasis, and drug-resistance in PDAC. Importantly, we also highlight the possible application of various therapeutic strategies including small interfering RNA, CRISPR-Cas9, antisense oligonucleotides, locked nucleic acid Gapmers, small molecules, aptamers, lncRNA promoter to target the lncRNA as a novel and viable options for treatment of PDAC.

Long noncoding RNA LINC00514 accelerates pancreatic cancer progression by acting as a ceRNA of miR-28-5p to upregulate Rap1b expression

Background

Pancreatic cancer (PC) is one of the most aggressive cancers and has an extremely poor prognosis worldwide. Long noncoding RNA (lncRNA) has been reported to be a potential prognostic biomarker in the initiation and prognosis of PC. Nevertheless, the biological functions and the detailed molecular mechanism of LINC00514 in PC remain unclear.

Methods

We measured the expression level of LINC00514 in PC tissues and cell lines by quantitative real-time PCR. Gain- and loss-of-function experiments were performed to explore the bioeffects of LINC00514 on PC development both in vitro and in vivo. Subcellular fractionation, luciferase reporter assay, RNA immunoprecipitation assay, pull-down assay and western blotting were performed to investigate the oncogenic molecular mechanisms of LINC00514.

Results

In this study, LINC00514 was shown to be upregulated in PC tissues and cell lines. Increased LINC00514 expression was significantly associated with the clinical progression and prognosis of PC patients. In addition, silencing LINC00514 inhibited PC cell proliferation, migration and invasion, while LINC00514 overexpression promoted these processes. Moreover, LINC00514 knockdown remarkably inhibited PC development and metastasis in vivo. Deeper investigations indicated that LINC00514 acted as a sponge for microRNA-28-5p (miR-28-5p) in PC and that Rap1b was a downstream target of miR-28-5p. Furthermore, the positive correlation of LINC00514 and Rap1b and the negative correlation between miR-28-5p and LINC00514 (or Rap1b) were revealed. Based on the rescue assays, Rap1b inhibition partially suppressed the oncogenic effect of LINC00514 overexpression on PC cell proliferation, migration and invasion.

Conclusions

This study is the first to characterize the oncogenic function of the long noncoding RNA LINC00514 in pancreatic cancer progression by acting as a competing endogenous RNA (ceRNA) of miR-28-5p to upregulate Rap1b expression. Understanding this molecular mechanism might contribute to further discoveries of better diagnostic and therapeutic options for pancreatic cancer.

Comprehensive Analysis of LincRNAs in Classical and Basal-Like Subtypes of Pancreatic Cancer

Pancreatic ductal adenocarcinomas (PDAC) belong to the deadliest malignancies in the western world. Mutations in TP53 and KRAS genes along with some other frequent polymorphisms occur almost universally and are major drivers of tumour initiation. However, these mutations cannot explain the heterogeneity in therapeutic responses and differences in overall survival observed in PDAC patients. Thus, recent classifications of PDAC tumour samples have leveraged transcriptome-wide gene expression data to account for epigenetic, transcriptional and post-transcriptional mechanisms that may contribute to this deadly disease. Intriguingly, long intervening RNAs (lincRNAs) are a special class of long non-coding RNAs (lncRNAs) that can control gene expression programs on multiple levels thereby contributing to cancer progression. However, their subtype-specific expression and function as well as molecular interactions in PDAC are not fully understood yet. In this study, we systematically investigated the expression of lincRNAs in pancreatic cancer and its molecular subtypes using publicly available data from large-scale studies. We identified 27 deregulated lincRNAs that showed a significant different expression pattern in PDAC subtypes suggesting context-dependent roles. We further analyzed these lincRNAs regarding their common expression patterns. Moreover, we inferred clues on their functions based on correlation analyses and predicted interactions with RNA-binding proteins, microRNAs, and mRNAs. In summary, we identified several PDAC-associated lincRNAs of prognostic relevance and potential context-dependent functions and molecular interactions. Hence, our study provides a valuable resource for future investigations to decipher the role of lincRNAs in pancreatic cancer.

hsa_circ_0026827 Promotes Osteoblast Differentiation of Human Dental Pulp Stem Cells Through the Beclin1 and RUNX1 Signaling Pathways by Sponging miR-188-3p

Previous studies have found that circular RNA (circRNA) hsa_circ_0026827 plays a role during osteoblast differentiation, but the mechanism is unclear. The aim of this study was to illuminate the role of hsa_circ_0026827 in human dental pulp stem cells (DPSCs) during osteoblast differentiation. The results show that hsa_circ_0026827 expression significantly increased during osteoblast differentiation, while knockdown of hsa_circ_0026827 suppressed DPSC-derived osteoblast differentiation. microRNA (miRNA) expression profile analysis showed that downregulation of hsa_circ_0026827 promoted miR-188-3p expression. miR-188-3p downregulation restored osteogenic differentiation of DPSCs after hsa_circ_0026827 was silenced. Luciferase reporter assays verified that miR-188-3p was the target of hsa_circ_0026827 and also demonstrated that Beclin1 and RUNX1 were miR-188-3p downstream targets. miR-188-3p overexpression suppressed DPSC osteogenic differentiation by targeting Beclin-1-mediated autophagy and runt-related transcription factor 1 (RUNX1). In vivo studies using a heterotopic bone model also found that hsa_circ_0026827 overexpression plays an important role in promoting heterotopic bone formation. In conclusion, our research indicates that hsa_circ_0026827 promotes osteoblast differentiation of DPSCs via Beclin1 and the RUNX1 signaling pathways by sponging miR-188-3p, which suggests novel therapeutics for osteoporosis treatment.

Silencing of lncRNA LINC00346 Inhibits the Proliferation and Promotes the Apoptosis of Colorectal Cancer Cells Through Inhibiting JAK1/STAT3 Signaling

Purpose

The study was aimed to investigate the effect and mechanism of lncRNA LINC00346 on cell proliferation and apoptosis of colorectal cancer (CRC).

Methods

The expression of lncRNA LINC00346 in CRC tissues and cells was detected by qRT-PCR. LINC00346 was overexpressed and silenced in HT29 and LoVo cells by the transfection of pcDNA-LINC00346 and si-LINC00346. The proliferation of CRC cells was detected by CCK-8 and colony-formation assay. The apoptosis was detected by flow cytometry assay. The expression of apoptosis-associated proteins (Caspase-3, Bcl-2, Bax) and JAK1/STAT3 signaling-associated proteins (JAK1, STAT3, p-JAK1, p-STAT3) was detected by Western blot. The tumor growth was detected in mice subcutaneous injected with transfected HT29 cells.

Results

LINC00346 was significantly upregulated in CRC tissues and cells. Overexpression of LINC00346 significantly increased the OD₄₅₀ values, number of colonies, decreased the apoptosis rate, upregulated Bcl-2, and downregulated Caspase-3 and Bax in HT29 and LoVo cells. Knockdown of LINC00346 exerted opposite results of proliferation and apoptosis on HT29 and LoVo cells. The expression levels of JAK1/JAK1 and p-STAT3/STAT3 were upregulated by LINC00346 overexpression. Tofacitinib (JAK1 inhibitor) reversed the tumor-promoting effect of LINC00346 overexpression on CRC cells. In vivo experiments further validated that LINC00346 overexpression promoted the growth of CRC xenograft tumors.

Conclusion

LncRNA LINC00346 promoted the proliferation and inhibited the apoptosis of CRC cells through activating JAK1/STAT3 signaling.

Comprehensive analysis of competitive endogenous RNAs network reveals potential prognostic lncRNAs in gastric cancer

Long non-coding RNAs (lncRNAs) are key regulators of a range of human diseases, including various cancers, with multiple previous studies having explored lncRNA dysregulation in the context of gastric cancer (GC). The present study sought to expand upon these previous results by downloading lncRNA, mRNA, and microRNA (miRNA) expression profiles derived from 180 GC tissues and 24 normal control tissues within the Cancer Genome Atlas (TCGA) database. These datasets were then interrogated to identify GC-related differentially expressed (DE) RNAs (|fold change| ≥ 2, FDR< 0.01), leading to the identification of 1946 DE lncRNAs, 123 DE miRNAs, and 3159 DE mRNAs. These results were then used to generate a putative GC-related competitive endogenous RNA (ceRNA) network composed of 131 lncRNAs, 9 miRNAs, and 78 mRNAs. Subsequent survival analyses based upon this network revealed 17 of these lncRNAs to be significantly associated with GC patient survival (P < 0.05). Further multivariable Cox regression and lasso analyses allowed for the construction of an 8-lncRNA risk score that was able to effectively predict GC patient survival with good discriminative ability. The Kaplan-Meier Plotter database further confirmed that network hub genes that were related to these 8 lncRNAs were associated with GC patient prognosis (P < 0.05). As the ceRNA network in the present study was constructed with a focus on both disease stage and differential gene expression, it represents a key resource that will offer valuable insights into the mechanistic roles of ceRNA pathways in GC development and progression.

Evaluation of expression of vitamin D receptor related lncRNAs in lung cancer

Lung cancer as the most common cancer in the world is associated with high rate of mortality. Previous studies have detected expression of vitamin D receptor (VDR) in lung cancer tissues and reported significant of this gene in determination of patients' survival. Methods: In the current study, we assessed expression of VDR and five long non-coding RNAs (lncRNAs) which have been associated with VDR (MALAT1, SNHG16, SNHG6, LINC00346, LINC00511) in 32 pairs of lung cancer tissues and adjacent non-cancerous tissues (ANCTs) using real time PCR method. Expression of VDR was significantly decreased in tumor tissues obtained from male patients compared with their matched ANCTs (ER = 0.31, P value = 0.02). However, this pattern was not detected in female subjects (ER = 0.93, P value = 0.94). Expression of LINC00346 was significantly decreased in tumoral tissues compared with ANCTs (Expression ratio (ER) = 0.38, P value = 0.03). When evaluating expression of this lncRNA based on the sex of patients, differences in its expression was only significant among males (ER = 0.3, P value = 0.04). VDR expression was significantly associated with sex of patients in a way that most male patients exhibited down-regulation of this gene in their tumor tissue samples compared with the paired ANCTs (P = 0.03). Expression levels of LINC00346 could discriminate lung cancer tissues from ANCTs with sensitivity of 83.3% and specificity of 52.4%. Correlations between expressions of SNHG6 and other genes were all significant in tumoral tissues but insignificant in ANCTs. The current investigation potentiates VDR and LINC00346 as possible participants in the pathogenesis of lung cancer.

LINC00152 promotes pancreatic cancer cell proliferation, migration and invasion via targeting miR-150

Pancreatic cancer (PC) is one of the top deaths causing cancers with low 5-year survival rate. Long non-coding RNAs (lncRNAs) are recognized as a crucial type of nonprotein-coding transcripts implicated in tumorigenesis. Emerging evidence has implied that LINC00152 exerts the potential oncogenic functions in various cancers. Nevertheless, the role of LINC00152 in PC remains elusive. In the present study, we found that LINC00152 was significantly up-regulated while miR-150 was down-regulated both in tissues and cell lines of PC, indicating their negative correlation in PC progression. Functionally, overexpression of LINC00152 promoted cell proliferation, migration and invasion, while LINC00152 knockdown reversed these effects. Mechanistic experiments reveal that miR-150 acted as a target of LINC00152 confirmed by luciferase reporter assay. Moreover, inhibition of miR-150 could markedly attenuate the suppression of cell proliferation, migration and invasion by knocking down LINC00152. Altogether, our findings concluded that LINC00152 facilitated PC progression through inhibiting miR-150 expression, indicating an innovative therapeutic target for PC.