Non-coding RNAs in pancreatic cancer: challenges and opportunities for clinical application

The intersection of ferroptosis and non-coding RNAs: a novel approach to ovarian cancer

Understanding the core principles of ovarian cancer has been significantly improved through the exploration of Ferroptosis, a type of cell death triggered by iron that leads to an increase in lipid peroxides. Current research has shed light on the critical functions of non-coding RNAs, such as circRNAs, lncRNAs, and miRNAs, in regulating ferroptosis in ovarian cancer. The aim of this paper is to comprehensively analyze how ncRNAs influence the development of ferroptosis in ovarian cancer cells. In-depth exploration is undertaken to understand the intricate ways in which ncRNAs regulate essential elements of ferroptosis, including iron management and lipid peroxidation levels. We also investigate their significant involvement in the progression of this type of cellular demise. It should be emphasized that ncRNAs can impact the synthesis of crucial proteins, such as GPX4, a key contributor to the cellular defense against oxidation, and ACSL4, involved in lipid formation. In addition, we examine the correlation between ncRNAs and well-known pathways associated with oxidative stress and cell death. The consequences of these discoveries are noteworthy, since focusing on particular ncRNAs could potentially render ovarian cancer cells more vulnerable to ferroptosis, effectively combating drug resistance problems. This discussion highlights the growing significance of ncRNAs in governing ferroptosis and their potential as useful biomarkers and treatment targets for ovarian cancer. We intend to promote additional research into the involvement of ncRNAs in controlling ferroptosis, based on current findings, with the ultimate goal of informing targeted therapeutic strategies and improving long-term treatment outcomes for individuals suffering from OC.

LncRNA MALAT-1 modulates EGFR-TKI resistance in lung adenocarcinoma cells by downregulating miR-125

Molecular targeted therapy resistance remains a major challenge in treating lung adenocarcinoma (LUAD). The resistance of Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs, epidermal growth factor receptor-tyrosine kinase inhibitor) plays a dominant role in molecular targeted therapy. Our previous research demonstrated the role of MALAT-1 (Metastasis-associated lung adenocarcinoma transcript 1) in the formation of Erlotinib-resistant LUAD cells. This study aims to uncover the mechanism of MALAT-1 overexpression in Erlotinib-resistant LUAD cells. The RT2 LncRNA PCR array system was used to explore MALAT-1 regulation in Erlotinib-resistant LUAD cells through patient serum analysis. Dual luciferase reporter experiments confirmed the binding between MALAT-1 and miR-125, leading to regulation of miR-125 expression. Functional assays were performed to elucidate the impact of MALAT1 on modulating drug resistance, growth, and Epithelial-mesenchymal transition (EMT, Epithelial-mesenchymal transition) in both parental and Erlotinib-resistant LUAD cells. The investigation unveiled the mechanism underlying the competing endogenous RNA (ceRNA, competing endogenouse RNA) pathway. MALAT1 exerted its regulatory effect on miR-125 as a competing endogenous RNA (ceRNA). Moreover, MALAT1 played a role in modulating the sensitivity of LUAD cells to Erlotinib. Rab25 was identified as the direct target of miR-125 and mediated the functional effects of MALAT1 in Erlotinib-resistant LUAD cells. In conclusion, our study reveals overexpress MALAT-1 cause the drug resistance of EGFR-TKIs in non-small cell lung cancer (NSCLC) through the MALAT-1/miR-125/Rab25 axis. These findings present a potential novel therapeutic target and perspective for the treatment of LUAD.

From powerhouse to regulator: The role of mitoepigenetics in mitochondrion-related cellular functions and human diseases

Beyond their crucial role in energy production, mitochondria harbor a distinct genome subject to epigenetic regulation akin to that of nuclear DNA. This paper delves into the nascent but rapidly evolving fields of mitoepigenetics and mitoepigenomics, exploring the sophisticated regulatory mechanisms governing mitochondrial DNA (mtDNA). These mechanisms encompass mtDNA methylation, the influence of non-coding RNAs (ncRNAs), and post-translational modifications of mitochondrial proteins. Together, these epigenetic modifications meticulously coordinate mitochondrial gene transcription, replication, and metabolism, thereby calibrating mitochondrial function in response to the dynamic interplay of intracellular needs and environmental stimuli. Notably, the dysregulation of mitoepigenetic pathways is increasingly implicated in mitochondrial dysfunction and a spectrum of human pathologies, including neurodegenerative diseases, cancer, metabolic disorders, and cardiovascular conditions. This comprehensive review synthesizes the current state of knowledge, emphasizing recent breakthroughs and innovations in the field. It discusses the potential of high-resolution mitochondrial epigenome mapping, the diagnostic and prognostic utility of blood or tissue mtDNA epigenetic markers, and the promising horizon of mitochondrial epigenetic drugs. Furthermore, it explores the transformative potential of mitoepigenetics and mitoepigenomics in precision medicine. Exploiting a theragnostic approach to maintaining mitochondrial allostasis, this paper underscores the pivotal role of mitochondrial epigenetics in charting new frontiers in medical science.

Liposomal nanostructures for Gemcitabine and Paclitaxel delivery in pancreatic cancer

Pancreatic cancer (PC) is an incurable disease with a high death rate in the world nowadays. Gemcitabine (GEM) and Paclitaxel (PTX) are considered as references of chemotherapeutic treatments and are commonly used in clinical applications. Factors related to the tumor microenvironment such as insufficient tumor penetration, toxicity, and drug resistance can limit the effectiveness of these therapeutic anticancer drugs. The use of different liposomal nanostructures is a way that can optimize the drug's effectiveness and reduce toxicity. Given the development of PC therapy, this review focuses on advances in Nano-formulation, characterization, and delivery systems of loaded GEM and PTX liposomes using chemotherapy, nucleic acid delivery, and stroma remodeling therapy. As a result, the review covers the literature dealing with the applications of liposomes in PC therapy.

Molecular and metabolic regulation of immunosuppression in metastatic pancreatic ductal adenocarcinoma

Immunosuppression is a hallmark of pancreatic ductal adenocarcinoma (PDAC), contributing to early metastasis and poor patient survival. Compared to the localized tumors, current standard-of-care therapies have failed to improve the survival of patients with metastatic PDAC, that necessecitates exploration of novel therapeutic approaches. While immunotherapies such as immune checkpoint blockade (ICB) and therapeutic vaccines have emerged as promising treatment modalities in certain cancers, limited responses have been achieved in PDAC. Therefore, specific mechanisms regulating the poor response to immunotherapy must be explored. The immunosuppressive microenvironment driven by oncogenic mutations, tumor secretome, non-coding RNAs, and tumor microbiome persists throughout PDAC progression, allowing neoplastic cells to grow locally and metastasize distantly. The metastatic cells escaping the host immune surveillance are unique in molecular, immunological, and metabolic characteristics. Following chemokine and exosomal guidance, these cells metastasize to the organ-specific pre-metastatic niches (PMNs) constituted by local resident cells, stromal fibroblasts, and suppressive immune cells, such as the metastasis-associated macrophages, neutrophils, and myeloid-derived suppressor cells. The metastatic immune microenvironment differs from primary tumors in stromal and immune cell composition, functionality, and metabolism. Thus far, multiple molecular and metabolic pathways, distinct from primary tumors, have been identified that dampen immune effector functions, confounding the immunotherapy response in metastatic PDAC. This review describes major immunoregulatory pathways that contribute to the metastatic progression and limit immunotherapy outcomes in PDAC. Overall, we highlight the therapeutic vulnerabilities attributable to immunosuppressive factors and discuss whether targeting these molecular and immunological "hot spots" could improve the outcomes of PDAC immunotherapies.

Liposome-based diagnostic and therapeutic applications for pancreatic cancer

Pancreatic cancer is one of the harshest and most challenging cancers to treat, often labeled as incurable. Chemotherapy continues to be the most popular treatment yet yields a very poor prognosis. The main barriers such as inefficient drug penetration and drug resistance, have led to the development of drug carrier systems. The benefits, ease of fabrication and modification of liposomes render them as ideal future drug delivery systems. This review delves into the versatility of liposomes to achieve various mechanisms of treatment for pancreatic cancer. Not only are there benefits of loading chemotherapy drugs and targeting agents onto liposomes, as well as mRNA combined therapy, but liposomes have also been exploited for immunotherapy and can be programmed to respond to photothermal therapy. Multifunctional liposomal formulations have demonstrated significant pre-clinical success. Functionalising drug-encapsulated liposomes has resulted in triggered drug release, specific targeting, and remodeling of the tumor environment. Suppressing tumor progression has been achieved, due to their ability to more efficiently and precisely deliver chemotherapy. Currently, no multifunctional surface-modified liposomes are clinically approved for pancreatic cancer thus we aim to shed light on the trials and tribulations and progress so far, with the hope for liposomal therapy in the future and improved patient outcomes. STATEMENT OF SIGNIFICANCE: Considering that conventional treatments for pancreatic cancer are highly associated with sub-optimal performance and systemic toxicity, the development of novel therapeutic strategies holds outmost relevance for pancreatic cancer management. Liposomes are being increasingly considered as promising nanocarriers for providing not only an early diagnosis but also effective, highly specific, and safer treatment, improving overall patient outcome. This manuscript is the first in the last 10 years that revises the advances in the application of liposome-based formulations in bioimaging, chemotherapy, phototherapy, immunotherapy, combination therapies, and emergent therapies for pancreatic cancer management. Prospective insights are provided regarding several advantages resulting from the use of liposome technology in precision strategies, fostering new ideas for next-generation diagnosis and targeted therapies of pancreatic cancer.

MicroRNAs and long non-coding RNAs in pancreatic cancer: From epigenetics to potential clinical applications

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two relevant classes of non-coding RNAs (ncRNAs) that play a pivotal role in a number of molecular processes through different epigenetic regulatory mechanisms of gene expression. As a matter of fact, the altered expression of these types of RNAs leads to the development and progression of a varied range of multifactorial human diseases. Several recent reports elucidated that miRNA and lncRNAs have been implicated in pancreatic cancer (PC). For instance, dysregulation of such ncRNAs has been found to be associated with chemoresistance, apoptosis, autophagy, cell differentiation, tumor suppression, tumor growth, cancer cell proliferation, migration, and invasion in PC. Moreover, several aberrantly expressed miRNAs and lncRNAs have the potential to be used as biomarkers for accurate PC diagnosis. Additionally, miRNAs and lncRNAs are considered as promising clinical targets for PC. Therefore, in this review, we discuss recent experimental evidence regarding the clinical implications of miRNAs and lncRNAs in the pathophysiology of PC, their future potential, as well as the challenges that have arisen in this field of study in order to drive forward the design of ncRNA-based diagnostics and therapeutics for PC.

A diagnostic and prognostic value of blood-based circulating long non-coding RNAs in Thyroid, Pancreatic and Ovarian Cancer

Several studies have demonstrated the potential of circulating long non-coding RNAs (lncRNAs) as promising cancer biomarkers. Herein, we addressed the regulatory role of circulating lncRNAs and their potential value as diagnostic/prognostic markers for thyroid, pancreatic and ovarian cancers. Furthermore, we analyzed and measured the clinical implications and association of lncRNAs with sensitivity, specificity, and area under the ROC curve (AUC). Based on our meta-analysis, we found that GAS8-AS1 could discriminate thyroid cancer from non-cancer and other cancers with higher accuracy (AUC = 0.746; sensitivity = 61.70%, and specificity = 90.00%). Similarly, for ovarian cancer, lncRNA RP5-837J1.2 was found to have ideal diagnostic potential with critical clinical specifications of AUC = 0.996; sensitivity = 97.30% and specificity = 94.60%. Whereas we could not find any lncRNA having high diagnostic/prognostic efficiency in pancreatic cancer. We believe that lncRNAs mentioned above may explore clinical settings for the diagnosis and prognosis of cancer patients.

Non-coding RNA-associated competitive endogenous RNA regulatory networks: Novel diagnostic and therapeutic opportunities for hepatocellular carcinoma

Hepatocellular carcinoma (HCC), as the most prevalent liver malignancy, is annually diagnosed in more than half a million people worldwide. HCC is strongly associated with hepatitis B and C viral infections as well as alcohol abuse. Obesity and nonalcoholic fatty liver disease (NAFLD) also significantly enhance the risk of liver cancer. Despite recent improvements in therapeutic approaches, patients diagnosed in advanced stages show poor prognosis. Accumulating evidence provides support for the regulatory role of non-coding RNAs (ncRNAs) in cancer. There are a variety of reports indicating the regulatory role of microRNAs (miRNAs) in different stages of HCC. Long non-coding RNAs (LncRNAs) exert their effects by sponging miRNAs and controlling the expression of miRNA-targeted genes. Circular RNAs (circRNAs) perform their biological functions by acting as transcriptional regulators, miRNA sponges and protein templates. Diverse studies have illustrated that dysregulation of competing endogenous RNA networks (ceRNETs) is remarkably correlated with HCC-causing diseases such as chronic viral infections, nonalcoholic steatohepatitis and liver fibrosis/cirrhosis. The aim of the current article was to provide an overview of the role and molecular mechanisms underlying the function of ceRNETs that modulate the characteristics of HCC such as uncontrolled cell proliferation, resistance to cell death, metabolic reprogramming, immune escape, angiogenesis and metastasis. The current knowledge highlights the potential of these regulatory RNA molecules as novel diagnostic biomarkers and therapeutic targets in HCC.

Role of Pancreatic Stellate Cell-Derived Exosomes in Pancreatic Cancer-Related Diabetes: A Novel Hypothesis

Pancreatic ductal adenocarcinoma (PDAC) is a devastating condition characterised by vague symptomatology and delayed diagnosis. About 30% of PDAC patients report a history of new onset diabetes, usually diagnosed within 3 years prior to the diagnosis of cancer. Thus, new onset diabetes, which is also known as pancreatic cancer-related diabetes (PCRD), could be a harbinger of PDAC. Diabetes is driven by progressive β cell loss/dysfunction and insulin resistance, two key features that are also found in PCRD. Experimental studies suggest that PDAC cell-derived exosomes carry factors that are detrimental to β cell function and insulin sensitivity. However, the role of stromal cells, particularly pancreatic stellate cells (PSCs), in the pathogenesis of PCRD is not known. PSCs are present around the earliest neoplastic lesions and around islets. Given that PSCs interact closely with cancer cells to drive cancer progression, it is possible that exosomal cargo from both cancer cells and PSCs plays a role in modulating β cell function and peripheral insulin resistance. Identification of such mediators may help elucidate the mechanisms of PCRD and aid early detection of PDAC. This paper discusses the concept of a novel role of PSCs in the pathogenesis of PCRD.

Long Non-coding RNA Small Nucleolar RNA Host Gene 14, a Promising Biomarker and Therapeutic Target in Malignancy

Small nucleolar RNA host gene 14 (SNHG14) is a long non-coding RNA found to be overexpressed in various types of cancers. Moreover, the expression level of SNHG14 was closely associated with multiple clinicopathological characteristics such as prognosis, tumor differentiation, TNM stage, and lymph node metastasis. Functionally, gain- and loss-of-function of SNHG14 revealed that overexpressed SNHG14 promoted cancer cell viability, invasion, and migration, whereas its down-regulation produced the opposite effect. Mechanistically, regulating its target gene expression by sponging distinct miRNAs might be the major mechanism underlying the oncogenic functions of SNHG14. Thus, SNHG14 might be a promising prognostic biomarker and therapeutic target for cancers. In this review, we discuss the expression profile, biological function, and molecular mechanisms of SNHG14 in cancers to provide a molecular basis for the clinical utility of SNHG14 in the future.

Carboxypeptidase E down-regulation regulates transcriptional and epigenetic profiles in pancreatic cancer cell line: A network analysis

BACKGROUND

Pancreatic cancer is a malignant tumor and its incidence has increased in recent years. Carboxypeptidase E (CPE) is a prohormone/proneuropeptide processing enzyme that has been shown to be associated with tumor growth and invasion in various cancers including pancreatic cancer.

OBJECTIVE

To understand the molecular mechanism underlying the proliferative effects of CPE in cancer cells.

METHODS

We down-regulated CPE gene expression in PANC-1 cell, a pancreatic cell line, and investigated mRNA, miRNA, circRNA and lncRNA expression profiling in PANC-1 cells from control group and CPE knock-down group by microarray analysis. We further validated the top 14 differentially expressed circRNAs by qRT-PCR.

RESULTS

Our results showed that CPE down-regulation caused decreased cell proliferation. The microarray data showed 107, 15, 299 and 360 differentially expressed mRNAs, miRNAs, circRNAs, and lncRNAs, respectively between control group and CPE knock-down group. Of Which, 41 mRNAs, 12 miRNAs, 133 circRNAs, and 262 lncRNAs were down-regulated; 66 mRNAs, 3 miRNAs, 166 circRNAs, and 98 lncRNAs were up-regulated. Bioinformatics analysis showed that the top significantly enriched pathways for the differentially expressed RNAs were related to cancer onset and/or progression, these included p53 signaling pathway, ECM-receptor interaction, focal adhesion and Wnt signaling pathway. We further performed network analysis to assess the mRNA, miRNA, circRNA and lncRNA correlations, and showed that HUWE1, hsa-miR-6780b-5p, has_circ_0058208 and lnc-G3BP1-3:8 were in the core position of the network.

CONCLUSIONS

Taken together, these results identified potential CPE regulated core genes and pathways for cell proliferation in pancreatic cancer cell, and therefore provide potential targets for the treatment of pancreatic cancer.

Long non-coding RNA LINC01137 contributes to oral squamous cell carcinoma development and is negatively regulated by miR-22-3p

PURPOSE

Long noncoding RNAs (lncRNAs) are emerging as key regulators in cancer initiation and progression. LINC01137 is a recently identified lncRNA of which the functional role in the development of oral squamous cell carcinoma (OSCC) has not been determined yet.

METHODS

We analyzed the expression of LINC01137 using a microarray-based OSCC gene expression dataset (GSE31056), and validated the results obtained using RT-qPCR in 26 pairs of primary OSCC tumor tissues and adjacent non-tumor tissues. The proliferative and invasive effects of LINC01137 on OSCC cells were determined using CCK-8, colony formation and transwell assays, respectively. Targeted binding between miR-22-3p and LINC01137 was verified using a dual luciferase reporter assay.

RESULTS

We found that LINC01137 was significantly upregulated in primary OSCCs. LINC01137 knockdown inhibited OSCC cell proliferation, migration and invasion, whereas LINC01137 overexpression induced opposite effects. LINC01137 upregulation along with p53 inhibition enhanced the malignant transformation of oral cells. In addition, we found that miR-22-3p can directly target LINC01137 through interaction with a putative miR-22-3p-binding site present within the LINC01137 sequence. A significant negative correlation was observed between LINC01137 and miR-22-3p expression in primary OSCC specimens. Exogenous overexpression of miR-22-3p markedly reduced the endogenous expression level of LINC01137 in OSCC cells. Additional functional assays showed that miR-22-3p overexpression enhanced the inhibitory effect of siRNA-mediated LINC01137 silencing on OSCC cell proliferation, migration and invasion, whereas miR-22-3p inhibition had the opposite effect.

CONCLUSIONS

Our results indicate that LINC01137 functions as an oncogenic lncRNA in OSCC. miR-22-3p can directly target LINC01137 and negatively regulate its expression and function.

HOTTIP polymorphism may affect gastric cancer susceptibility by altering HOTTIP expression

Background: Non-coding RNA polymorphisms can affect disease risk and prognosis by influencing gene expression. Here, we first investigated the association between single nucleotide polymorphisms (SNPs) of long non-coding RNA (lncRNA) HOTTIP and gastric cancer risk/prognosis. Methods: A total of five HOTTIP SNPs among 627 gastric cancer cases and 935 controls were tested by Kompetitive Allele Specific PCR (KASP) assay. The functional SNPs underwent eQTL analysis and the expression of HOTTIP was assessed by quantitative RT-PCR. Results: The rs2067087 and rs3807598 SNPs of HOTTIP increased susceptibility to gastric cancer (rs2067087: dominant model, P=0.008, odds ratio (OR) = 1.35; rs3807598: recessive model, P=0.037, OR = 1.29). Both HOTTIP rs2067087 and rs3807598 could affect the expression of mature lncRNA (P=0.003 and P=0.032, respectively). Conclusion: The rs2067087 and rs3807598 SNPs of HOTTIP are associated with gastric cancer risk, possibly by affecting the expression of mature HOTTIP.

Crosstalk between miRNAs and signaling pathways involved in pancreatic cancer and pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer-related deaths worldwide with 5-year survival rates below 8%. Most patients with PC and pancreatic ductal adenocarcinoma (PDAC) die after relapse and cancer progression as well as resistance to treatment. Pancreatic tumors contain a high desmoplastic stroma that forms a rigid mass and has a potential role in tumor growth and metastasis. PC initiates from intraepithelial neoplasia lesions leading to invasive cancer through various pathways. These lesions harbor particular changes in signaling pathways involved in the tumorigenesis process. These events affect both the epithelial cells, including the tumor and the surrounding stroma, and eventually lead to the formation of complex signaling networks. Genetic studies of PC have revealed common molecular features such as the presence of mutations in KRAS gene in more than 90% of patients, as well as the inactivation or deletion mutations of some tumor suppressor genes including TP53, CDKN2A, and SMAD4. In recent years, studies have also identified different roles of microRNAs in PC pathogenesis as well as their importance in PC diagnosis and treatment, and their involvement in various signaling pathways. In this study, we discussed the most common pathways involved in PC and PDAC as well as their role in tumorigenesis and progression. Furthermore, the miRNAs participating in the regulation of these signaling pathways in PC progression are summarized in this study. Therefore, understanding more about pathways involved in PC can help with the development of new and effective therapies in the future.

EIF3B promotes cancer progression in pancreatic cancer

BACKGROUND

This study aimed to analyze the relative expression of Eukaryotic Translation Initiation Factor 3 Subunit B (EIF3B) in pancreatic cancer and elucidate its contribution to this disease.

METHODS

Relative expression of EIF3B in pancreatic cancer was analyzed by immunohistochemistry. Cell viability was determined by the MTT assay and cell proliferation was measured by direct cell counting. Cell apoptosis was detected by Annexin V staining followed by flow cytometry analysis, and cell cycle was analyzed by PI staining. The differential expression gene analysis was performed by microarray. Tumor progression in response to EIF3B deficiency in vivo was investigated using the xenograft tumor model.

RESULTS

We found aberrantly high expression of EIF3B in pancreatic cancer, which associated with unfavorable prognosis. Knockdown of EIF3B greatly compromised cell viability and proliferation in both SW1990 and PANC-1 cells. Furthermore, EIF3B deficiency induced cell cycle arrest and spontaneous apoptosis. In vivo tumor progression was significantly suppressed by EIF3B silencing in the xenograft mouse model. Mechanistically, we characterized down-regulation of CDH1 and IRS1 and up-regulation of DDIT3, PTEN and CDKN1B, in response to EIF3B knockdown, which might mediate the oncogenic effect of EIF3B in pancreatic cancer.

CONCLUSIONS

Our data uncovered the oncogenic role of EIF3B in pancreatic cancer.

Tumor Suppressor LINC02487 Inhibits Oral Squamous Cell Carcinoma Cell Migration and Invasion Through the USP17-SNAI1 Axis

Purpose

The aim of this study was to explore the functions and associated mechanisms of long noncoding RNA LINC02487 in oral squamous cell carcinoma (OSCC).

Methods

The relative expression levels of LINC02487 in OSCC cell lines and tissue samples were examined by RT-qPCR. Intracellular localization was determined using RNA fluorescence in situ hybridization. LINC02487 was cloned into the pCMV-puro vector and then introduced into OSCC cells using lentiviral transfection. Cell processes, such as proliferation, apoptosis, migration, and invasion, were subsequently examined. LINC02487-binding proteins were identified by ChIRP-MS and confirmed by RNA immunoprecipitation. Protein expression was determined by western blotting assay.

Results

LINC02487 has been reported to be downregulated in OSCC. Here, we confirmed that the expression of LINC02487 was reduced in 6 OSCC cell lines compared with that in immortalized normal oral epithelial cells and in 50 OSCC samples compared with paired adjacent normal tissue in a Chinese population and that LINC02487 expression levels were associated with cancer metastasis. We further identified that LINC02487 was localized to the cytoplasm, aggregated around the nuclear membrane. Functional studies demonstrate that overexpression of LINC02487 significantly suppresses cell migration and invasion and also inhibits cell proliferation. For the mechanism, we reveal that LINC02487 directly binds to USP17, a deubiquitinating enzyme, and regulates cell migration and invasion through the USP17-SNAI1 axis in a process that involves epithelial-mesenchymal transition (EMT).

Conclusion

Our results confirm that long noncoding RNA LINC02487 is downregulated in OSCC tissue samples and cell lines. We also find that LINC02487 acts as a tumor suppressor through the USP17-SNAI1 axis.

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.

Inhibition of miR-21 Regulates Mutant KRAS Effector Pathways and Intercepts Pancreatic Ductal Adenocarcinoma Development

Almost all pancreatic ductal adenocarcinomas (PDA) develop following KRAS activation, which triggers epithelial transformation and recruitment of desmoplastic stroma through additional transcriptional and epigenetic regulation, but only a few of these regulatory mechanisms have been described. We profiled dysregulated miRNAs starting with the earliest premalignant pancreatic intraepithelial neoplasias (PanIN) in genetically engineered mutated KRAS and P53 (KPC) mice programmed to recapitulate human PDA tumorigenesis. We identified miR-21 and miR-224 as cell-specific and compartment-specific regulators in PanINs and PDA. miR-21 is overexpressed in tumor epithelial cells of premalignant ducts, while miR-224 is overexpressed in cancer-associated fibroblasts in PDA stroma. Inhibition of miR-21 reverted protumorigenic functionalities to baseline levels. Overexpression of miR-224 induced activated phenotypes in normal fibroblasts. In vivo miR-21 inhibition improved survival in established PDA. Importantly, early systemic miR-21 inhibition completely intercepted premalignant progression. Finally, an evaluation of miR-21 expression in the PDA cohort of The Cancer Genome Atlas identified a correlation between tumor epithelial cell content and miR-21 expression in human tumors providing further rationale for conducting human studies. Thus, miR-21 may be useful for early PanIN detection, and for intercepting developing premalignant pancreatic lesions and other KRAS-driven premalignancies.

Bioinformatic Analysis Suggests That Three Hub Genes May Be a Vital Prognostic Biomarker in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide due to its ineffective diagnosis and poor prognosis. It is essential to identify differentially expressed genes (DEGs) in PDAC to gain new insights into its underlying molecular mechanisms, as well as identify potential diagnostic and therapeutic targets. We screened 135 DEGs from the GSE15417, GSE16515, and GSE28735 PDAC and normal pancreatic tissue microarray data sets, and identified 16 DEGs that were correlated with PDAC prognosis through the Kaplan-Meier survival analysis and log-rank tests. The Cancer Genome Atlas and Oncomine databases validated the expression levels of 16 candidate genes (SLC6A14, GPRC5A, IFI27, ERP27, SDR16C5, SIDT2, TCN1, COL12A1, MMP1, CEACAM6, DKK1, ITGA2, KRT19, PLAU, ANO1, and GABRP). Weighted gene coexpression network analysis (WGCNA) and protein and protein interaction (PPI) analysis identified three hub genes-ERP27, ITGA2, and MMP1-that are likely important in PDAC prognosis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis demonstrated that they were enriched in functions of extracellular matrix organization, extracellular structure organization, and positive regulation of cell migration. Taken together, we identified three pivotal genes for PDAC, which can improve our understanding of its pathogenesis, progression, and prognosis.

miRNAs in the Diagnosis and Prognosis of Skin Cancer

Skin cancer is, at present, the most common type of malignancy in the Caucasian population. Its incidence has increased rapidly in the last decade for both melanoma and non-melanoma skin cancer. Differential expression profiles of microRNAs (miRNAs) have been reported for a variety of different cancers, including skin cancers. Since miRNAs’ discovery as regulators of gene expression, their importance grew in the field of oncology. miRNAs can post-transcriptionally regulate gene expression, tumor initiation, development progression, and aggressiveness. Nowadays, these short regulatory RNAs are perceived as one of the epigenetic markers for the identification of new diagnostic and/or prognostic molecular markers. Moreover, as miRNAs can drive tumorigenesis, they might eventually represent new therapy targets. Some miRNAs are pleiotropic, such as miR-214, which was found deregulated in several other tumors besides skin cancers. Some others are specific for one or more skin cancer types, like miR-21 and miR-221 for cutaneous melanoma and cutaneous squamous carcinoma or miR-155 for melanoma and cutaneous lymphoma. The goal of this review was to summarize some of the main miRNA detection technologies that are used to evaluate miRNAs in tissues and body fluids. Furthermore, their quantification limits, conformity, and robustness are discussed. Aberrant miRNA expression is analyzed for cutaneous melanoma, cutaneous squamous cell carcinoma (CSCC), skin lymphomas, cutaneous lymphoma, and Merkel cell carcinoma (MCC). In this type of disease, miRNAs are described as potential biomarkers to diagnose early lesion and/or early metastatic disease. In the future, whether in tissue or circulating in body fluids, miRNAs will gain their place in skin cancer diagnosis, prognosis, and future therapeutic targets.

Long noncoding RNA RHPN1-AS1 promotes colorectal cancer progression via targeting miR-7-5p/OGT axis

Background

Rhophilin Rho GTPase binding protein 1 antisense RNA 1 (RHPN1-AS1) is a newly discovered oncogene in several diseases, such as breast cancer, non-small cell lung cancer and uveal melanoma. Nevertheless, its molecular role in colorectal cancer (CRC) remains unknown. This paper explored the role of RHPN1-AS1 in CRC progression.

Methods

qRT-PCR was used to detect relevant RNAs expression. CCK-8, EdU, flow cytometry, Transwell and western blot assays were performed to investigate the function of RHPN1-AS1 in CRC cells. Xenograft model was constructed to evaluate the effects of RHPN1-AS1 on tumor growth in vivo. Mechanical experiments were performed to investigate the relationship between relative genes.

Results

RHPN1-AS1 was significantly overexpressed in CRC cell lines. Knockdown of RHPN1-AS1 could inhibit cell proliferation, while stimulating cell apoptosis in vitro. Cell migration and invasion abilities were greatly suppressed after silencing RHPN1-AS1. Besides, signal transducer and activator of transcription 3 (STAT3) served as transcription factor of RHPN1-AS1. Moreover, miR-7-5p was identified as a target of RHPN1-AS1 and was negatively regulated by RHPN1-AS1 in CRC. MiR-7-5p inhibition rescued the oncogenic function of RHPN1-AS1. Additionally, O-GlcNAcylation transferase (OGT) was the downstream target of miR-7-5p. OGT overexpression could abrogate the anti-tumor effects of RHPN1-AS1 knockdown on CRC.

Conclusion

RHPN1-AS1 regulates CRC by mediating OGT through sponging miR-7-5p, suggesting that RHPN1-AS1 might be a potential therapeutic target for CRC.

Roles and potential applications of lncRNAs in HIV infection

Long non-coding RNAs (lncRNAs) are defined as a class of RNA molecules with a length of more than 200 nucleotides that are not translated into protein, and are known to participate in a variety of biological processes. They have recently been implicated as having roles in viral infections, and several research groups have identified that complex interactions exist between lncRNAs and the progression of human immunodeficiency virus (HIV) infection. lncRNAs derived from both the human host and HIV itself are emerging as key regulators of various cellular functions, playing crucial roles in virus-host interactions and viral pathogenesis. This review provides a brief discussion of the roles and associated mechanisms of lncRNAs in HIV infection. Moreover, due to the continued lack of effective HIV vaccines or treatments, we provide an insight into the complex interplay between lncRNAs and HIV and suggest innovative therapeutic strategies for HIV/acquired immunodeficiency syndrome (AIDS). The available data on lncRNAs that have been associated with HIV infection and their potential applications for the treatment of HIV are summarized for the first time, providing a new perspective for the future development of therapeutic strategies.

Unravelling the role of long non-coding RNA - LINC01087 in breast cancer

Apoptosis is a 'programmed fate' of all cells participating in diverse physiological and pathological conditions. The role of critical regulators and their involvement in this complex multi-stage process of apoptosis weaved around non-coding RNAs (ncRNAs) is poorly deciphered in breast carcinoma (BC). Aberrant expression patterns of the ncRNAs and their interacting partners, either ncRNAs or coding RNAs or proteins at any point along these pathways, may lead to the malignant transformation of the affected cells, tumour metastasis and resistance to anticancer drugs. Longest non-coding type of ncRNAs (lncRNAs) have been considered as critical factors for the development and progression of breast cancer. The aim of our study was to identify set of novel lncRNAs interacting with microRNAs (miRNAs) or proteins that were significantly dysregulated in breast cancer using RNA-Sequencing (RNA-Seq) technique in different samples acting as oncogenic drivers contributing to cancerous phenotype involved in post-transcriptional processing of RNAs. Four lncRNAs; LINC01087, lnc-CLSTN2-1:1, lnc-c7orf65-3:3 and LINC01559:2 were selected for further analysis. Gene expression analysis of over-expressed LINC01087 in vitro reduced both cell viability and apoptosis. We integrated miRNA and mRNA (hsa-miR-548 and AKT1) expression profiles with curated regulations with lncRNA (LINC01087) which has not been previously associated with any breast cancer type, using different computational tools. The network (lncRNA→ miRNA→ mRNA) is promising for the identification of carcinoma associated genes and apoptosis signaling path highlighting the potential roles of LINC01087, hsa-miR548n, AKT1 gene which may play crucial role in proliferation.

Long noncoding RNA HOTTIP overexpression: A potential prognostic biomarker in prostate cancer

HOXA transcript at the distal tip (HOTTIP) is a long noncoding RNA (lncRNA), which is >200 nucleotides in length. HOTTIP expression has been demonstrated to play a crucial oncogenic role in cancer pathogenesis, and is said to be associated with poor human cancer prognosis. In prostate cancer, HOTTIP has been identified as an oncogene, but its clinicopathologic significance remains unclear. Array-based qRT-PCR was used to investigate lncRNA levels in 10 pairs of prostate cancer tissues and non-neoplastic parenchyma. Tissue microarray (TMA) was constructed using a total of 70 surgically resected prostatic adenocarcinoma tissues obtained from the Korea University Anam Hospital from 2009 to 2013. HOTTIP expression was determined by RNA in situ hybridization(ISH) and was correlated with clinicopathologic features. Increased HOTTIP expression was observed in all available prostate cancer tissue specimens compared with that in paired normal tissue. High HOTTIP expression was positively associated with bad clinicopathologic features, including higher pathologic T stage (p < 0.001), presence of extraprostatic extension (p < 0.001), seminal vesicle invasion (p < 0.001), perineural invasion (p < 0.001), and the tumor involvement of resection margin (p = 0.044). In particular, significantly increased HOTTIP expression was observed in specimens from patients in the high or very high-risk group, according to the 2018 National Comprehensive Cancer Network (NCCN) guidelines (p < 0.001). Also, patients with high HOTTIP expression showed poorer overall survival than those with low expression. In conclusion, we analytically validated the poor prognostic significance of HOTTIP overexpression and its association with bad clinicopathologic features, and present HOTTIP as a potential prognostic biomarker in prostate cancer.

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.

Role of non-coding RNA in pancreatic cancer

Pancreatic cancer is a malignant disease that develops rapidly and carries a poor prognosis. Currently, surgery is the only radical treatment. Non-coding RNAs (ncRNAs) are protein-free RNAs produced by genome transcription; they play important roles in regulating gene expression, participating in epigenetic modification, cell proliferation, differentiation and reproduction. ncRNAs also play key roles in the development of cancer; microRNA (miRNA) and long non-coding RNA (lncRNA) may lead the way to new treatments for pancreatic cancer. miRNAs are short-chain ncRNAs (19–24 nt) that inhibit the degradation of protein translation or their target gene mRNAs to regulate gene expression. lncRNAs contain >200 nt of ncRNA and play important regulatory roles in a number of malignant tumors, in terms of tumor cell proliferation, apoptosis, invasion and distant metastasis. lncRNAs can be exploited for the diagnosis and treatment of pancreatic cancer and have substantial prospects for clinical application. Nevertheless, the molecular mechanism of their regulation and function, as well as the significance of other ncRNAs, such as piwi-interacting RNA, in the pathogenesis of pancreatic cancer, are largely unknown. In this review, the structures of ncRNAs with various classifications, as well as the functions and important roles of ncRNAs in the diagnosis and treatment of pancreatic cancer are reviewed.

Downregulation of miR-216a-5p by long noncoding RNA PVT1 suppresses colorectal cancer progression via modulation of YBX1 expression

Purpose

Increasing evidence has demonstrated that microRNAs (miRNAs) are closely related to the occurrence and development of tumors. MiR-216a-5p, located at 2p16.1, has been shown to suppress proliferation of cancerous cells. However, its expression and function in colorectal cancer (CRC) remain unclear.

Materials and methods

The significance of miR-216a-5p in CRC was studied by analyzing miR-216a-5p expression in CRC tissues and its association with clinicopathological parameters. CRC cells, stably overexpressing miR-216a-5p, were evaluated for cell proliferation and metastasis using cell counting kit-8 (CCK-8) and transwell assay methods. Epithelial–mesenchymal transition (EMT) pathway was analyzed by Western blotting. Bioinformatics, quantitative real-time polymerase chain reaction (RT-qPCR), and luciferase reporter assay were performed to define the regulation of PVT1/miR-216a-5p/Y Box Binding Protein 1 (YBX1) axis in CRC.

Results

The expression of miR-216a-5p was found to be significantly downregulated in CRC and was correlated with the various stages and differentiation degree of the tumors. Moreover, the overexpression of miR-216a-5p could significantly inhibit the tumor growth, metastasis, and EMT progression in CRC. Furthermore, the expression of miR-216a-5p was negatively correlated with the expression of PVT1, and PVT1 could reverse tumor suppressive effect of miR-216a-5p in CRC cells. Finally, YBX1 might be the key target of PVT1/miR-216a-5p axis in CRC.

Conclusion

Downregulation of miR-216a-5p by PVT1 could suppress CRC progression via modulating YBX1 expression.

Four novel polymorphisms in long non-coding RNA HOTTIP are associated with the risk and prognosis of colorectal cancer

Background: The role of long non-coding RNA (lncRNA) HOXA transcript at the distal tip (HOTTIP) as an oncogene in varieties of human cancer including colorectal cancer (CRC) has been extensively researched. The expression and function of lncRNAs could be affected by single nucleotide polymorphisms (SNPs), which are associated with cancer susceptibility and prognosis. However, no investigation has focused on the association between HOTTIP SNPs and CRC. The aim of the present study was to explore the association of polymorphisms in the lncRNA HOTTIP gene with CRC risk and prognosis. Methods: A total of 1848 subjects were enrolled in our study, including 884 CRC cases and 964 controls. Genotyping for five HOTTIP tagSNPs (rs3807598, rs17501292, rs2067087, rs17427960, and rs78248039) was performed by applying Kompetitive allele specific PCR (KASP). Results: The results showed three SNPs (rs3807598, rs2067087, and rs17427960) were associated with enhanced CRC risk both in overall and stratified analysis. One polymorphism, rs17501292, could improve the overall survival (OS) of CRC patients in the tumor of ulcerative/invasive-type subgroup. Conclusion: These findings suggest HOTTIP SNPs could potentially be predictive biomarkers for CRC risk and prognosis. The present study provides clues for further exploration of novel lncRNA-based genetic biomarkers to predict CRC susceptibility as well as clinical outcome.

The role of lncRNA MSC-AS1/miR-29b-3p axis-mediated CDK14 modulation in pancreatic cancer proliferation and Gemcitabine-induced apoptosis

Pancreatic ductal adenocarcinoma (PDAC) remains a leading cause of cancer-related death due to the failure of traditional therapies. In the present study, we attempted to construct a lncRNA-miRNA-mRNA network which may modulate PDAC cell proliferation and Gemcitabine-induced cell apoptosis starting from CDK14, a new member of the CDK family and an oncogene in many cancers. Based on TCGA data, a significant positive correlation was observed between lncRNA MSC-AS1 and CDK14. Moreover, MSC-AS1 expression was upregulated in PDAC tissues. Higher MSC-AS1 expression was correlated with poorer prognosis in patients with PDAC. MSC-AS1 knockdown in Panc-1 and BxPC-3 cells significantly inhibited the cell proliferation. Moreover, miR-29b-3p, which has been reported to act as a tumor suppressor, was predicted to bind to both MSC-AS1 and CDK14. Contrary to MSC-AS1, higher miR-29b-3p expression was correlated to better prognosis in patients with PDAC. In both PDAC cell lines, miR-29b-3p negatively regulated MSC-AS1 and CDK14. As confirmed using luciferase reporter gene and RIP assays, MSC-AS1 served as a ceRNA for miR-29b-3p to counteract miR-29b-mediated CDK14 repression. MSC-AS1 knockdown inhibited CDK14 protein levels and PDAC proliferation and enhanced gemcitabine-induced cell death and apoptosis while miR-29b-3p inhibition exerted an opposing effect; the effect of MSC-AS1 knockdown was partially attenuated by miR-29b-3p inhibition. Taken together, we demonstrated that MSC-AS1/miR-29b-3p axis modulates the cell proliferation and GEM-induced cell apoptosis in PDAC cell lines through CDK14. We provided a novel experimental basis for PDAC treatment from the perspective of lncRNA-miRNA-mRNA network.

LncRNA H19/miR-194/PFTK1 axis modulates the cell proliferation and migration of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a huge challenge due to its high mortality and morbidity; gene therapy might be a promising treatment for PDAC. The critical role of Wnt-signaling pathway in cancer pathogenesis has been widely recognized; cyclin-dependent kinase 14 (CDK14, PFTK1)-induced low-density lipoprotein receptor-related proteins 5/6 (LRP5/6) phosphorylation is an important issue in Wnt-signaling activation. Long noncoding RNA (LncRNA)-microRNA (miRNA)-messenger RNA (mRNA) modulating the pathogenesis of cancers has been regarded as a major mechanism. In the current study, upregulated lncRNAs positively correlated with PFTK1 were analyzed and selected using The Cancer Genome Atlas (TCGA) database. Of them, lncRNA H19 can activate Wnt signaling in cancers. In PDAC tissues, the expression of H19 and PFTK1 were upregulated; H19 knockdown suppressed the cell proliferation and migration of PDAC, while PFTK1 overexpression partially attenuated the suppressive effect of H19 knockdown. As analyzed by TCGA and predicted by online tools, miR-194 was negatively correlated with PFTK1 and might bind to both H19 and PFTK1, which was further confirmed by luciferase reporter and RNA immunoprecipitation assays. Moreover, the effect of H19 knockdown on PFTK1 protein and the cell proliferation and migration could be partially reversed by miR-194 inhibition; H19/miR-194 axis modulated PDAC cell proliferation and migration through PFTK1 downstream Wnt signaling. Results suggested that rescuing miR-194 expression in PDAC can inhibit lncRNA H19 and PFTK1 expression, subsequently suppressing PDAC cell proliferation and migration. Due to the complexity of the lncRNA-miRNA-mRNA network, further in vivo experiments examining potential side effects are needed in future study to explore the clinical application of these findings.

miR-216a-5p inhibits malignant progression in small cell lung cancer: involvement of the Bcl-2 family proteins

Objective

microRNAs are regulatory molecules regarded as important in the pathogenesis of different types of tumors. microRNA-216a (miR-216a-5p) has been identified as a tumor suppressor in multiple malignancies. However, the role of miR-216a-5p in the pathogenesis of small cell lung cancer (SCLC) remains obscure. The objective of this study was to investigate the role of the miR-216a-5p/Bcl-2 axis in SCLC pathogenesis.

Materials and methods

All the experimental methods used were as follows: microarray analysis, cell culture, transient, and stable gene transfection; real-time fluorescence PCR; Western blot; flow cytometry for cell cycle analysis; in vitro proliferation assay; in vitro wound healing experiment; in vivo xenograft model in nude mice; and dual luciferase reporter assay. All statistical analyses were carried out using GraphPad Prism 7 software. Statistical significance was analyzed by Student’s t-test or one-way ANOVA. P <0.05 (typically compared with the negative control group) was considered as significant and is marked with an asterisk in the figures.

Results

In this study, we observed that miR-216a-5p is downregulated in SCLC cell lines compared to that in the normal human bronchial epithelial cell line 16-HBE. In vitro and in vivo experiments demonstrate that upregulation of miR-216a-5p significantly decreased cell growth and migration and its downregulation increased SCLC cell proliferation and migration and influenced the cell cycle. Using bioinformatics analyses, we predicted that the important antiapoptotic gene Bcl-2 is targeted by miR-216a-5p, and we identified a functional miR-216a-5p binding site in the 3′-UTR of Bcl-2 using luciferase reporter assay. Furthermore, we determined that suppression of miR-216a-5p modulated the expression of Bcl-2, Bax, and Bad proteins (Bcl-2 family proteins), while Bcl-2 knockdown abrogated the effect of miR-216a-5p downregulation on cell proliferation, cell migration, and the cell cycle.

Conclusion

Taken together, these findings suggest that miR-216a-5p regulates SCLC biology via Bcl-2 family proteins. Therefore, our study highlights the role of the miR-216a-5p/Bcl-2 axis in SCLC pathogenesis.

The emerging role of lncRNAs in the regulation of cancer stem cells

BACKGROUND

Tumors contain a functional subpopulation of cells that exhibit stem cell properties. These cells, named cancer stem cells (CSCs), play significant roles in the initiation and progression of cancer. Long non-coding RNAs (lncRNAs) can act at the transcriptional, posttranscriptional and translational level. As such, they may be involved in various biological processes such as DNA damage repair, inflammation, metabolism, cell survival, cell signaling, cell growth and differentiation. Accumulating evidence indicates that lncRNAs are key regulators of the CSC subpopulation, thereby contributing to cancer progression. The aim of this review is to overview current knowledge about the functional role and the mechanisms of action of lncRNAs in the initiation, maintenance and regulation of CSCs derived from different neoplasms. These lncRNAs include CTCF7, ROR, DILC, HOTAIR, H19, HOTTIP, ATB, HIF2PUT, SOX2OT, MALAT-1, CUDR, Lnc34a, Linc00617, DYNC2H1-4, PVT1, SOX4 and ARSR Uc.283-plus. Furthermore, we will illustrate how lncRNAs may regulate asymmetric CSC division and contribute to self-renewal, drug resistance and EMT, thus affecting the metastasis and recurrence of different cancers. In addition, we will highlight the implications of targeting lncRNAs to improve the efficacy of conventional drug therapies and to hamper CSC survival and proliferation.

CONCLUSIONS

lncRNAs are valuable tools in the search for new targets to selectively eliminate CSCs and improve clinical outcomes. LncRNAs may serve as excellent therapeutic targets because they are stable, easily detectable and expressed in tissue-specific contexts.

Liquid biopsy in pancreatic cancer: the beginning of a new era

With dismal survival rate pancreatic cancer remains one of the most aggressive and devastating malignancy. Predominantly, due to the absence of a dependable methodology for early identification and limited therapeutic options for advanced disease. However, it takes over 17 years to develop pancreatic cancer from initiation of mutation to metastatic cancer; therefore, if diagnosed early; it may increase overall survival dramatically, thus, providing a window of opportunity for early detection. Recently, genomic expression analysis defined 4 subtypes of pancreatic cancer based on mutated genes. Hence, we need simple and standard, minimally invasive test that can monitor those altered genes or their associated pathways in time for the success of precision medicine, and liquid biopsy seems to be one answer to all these questions. Again, liquid biopsy has an ability to pair with genomic tests. Additionally, liquid biopsy based development of circulating tumor cells derived xenografts, 3D organoids system, real-time monitoring of genetic mutations by circulating tumor DNA and exosome as the targeted drug delivery vehicle holds lots of potential for the treatment and cure of pancreatic cancer. At present, diagnosis of pancreatic cancer is frantically done on the premise of CA19-9 and radiological features only, which doesn't give a picture of genetic mutations and epigenetic alteration involved. In this manner, the current diagnostic paradigm for pancreatic cancer diagnosis experiences low diagnostic accuracy. This review article discusses the current state of liquid biopsy in pancreatic cancer as diagnostic and therapeutic tools and future perspectives of research in the light of circulating tumor cells, circulating tumor DNA and exosomes.

Serum exosomal miR-301a as a potential diagnostic and prognostic biomarker for human glioma

PURPOSE

Exosomal miRNAs that play an important role in cell-cell communication have attracted major attention as potential diagnostic and prognostic biomarkers for various cancers. The aim of this study was to determine the diagnostic/prognostic significance of serum exosomal miR-301a in glioma patients.

METHODS

Quantitative real-time PCR was used to determine the serum exosomal expression levels of miR-301a. Kaplan-Meier survival analyses, Cox regression analyses and ROC working curve analyses were applied to assess the diagnostic and prognostic values of miR-301a in glioma patients. Also, several in vitro assays were used, including proliferation, invasion and cell signaling assays.

RESULTS

First, we established that serum exosomal miR-301a extracted from grade IV glioblastoma (GBM) patients was biologically active, i.e., promoted the proliferation and invasion of glioma-derived H4 cells. Subsequently, we found that serum exosomal miR-301a levels were significantly up-regulated in glioma patients compared to healthy controls. Additionally, we found that increased serum exosomal miR-301a levels were correlated with ascending pathological grades and lower Karnofsky performance status (KPS) scores. Importantly, we also found that the serum exosomal miR-301a levels were significantly reduced after surgical resection of primary tumors and increased again during GBM recurrence. Kaplan-Meier analysis of patients with an advanced pathological grade (III or IV) and an increased serum exosomal miR-301a level revealed a longer overall survival (OS) compared to those with a lower level (p < 0.01). Both univariate and multivariate Cox regression analyses confirmed that serum exosomal miR-301a levels are independently associated with OS. Finally, we found that miR-301a may activate the AKT and FAK signaling pathways by down regulating PTEN.

CONCLUSIONS

Our data indicate that serum exosomal miR-301a levels may reflect the cancer-bearing status and pathological changes in glioma patients. Serum exosomal miR-301a expression may serve as a novel biomarker for glioma diagnosis and as a prognostic factor for advanced grade disease.

CCAT2 is an oncogenic long non-coding RNA in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive with poor prognosis. Long non-coding RNAs (lncRNAs), a group of non-coding RNAs, play important roles in the progression of PDAC. This study aimed to investigate the potential involvement of lncRNA CCAT2 in PDAC tumorigenesis.

Methods

Expression of CCAT2 was detected by quantitative real-time PCR (qRT-PCR) in 80 human PDAC tissues and three PDAC cell lines. The effects of CCAT2 silencing in PANC-1 cells on cell proliferation and invasion were studied using MTT assay and transwell assay, respectively. The effect of CCAT2 silencing on tumorigenesis was assessed by PANC-1 xenograft in vivo. Using si-KRAS, the role of KRAS to regulate CCAT2 was evaluated by qRT-PCR and luciferase reporter assay. The involvement of MEK/ERK and PI3K/AKT signaling in CCAT2 regulation was investigated by pathway inhibitors PD98059 and LY294002, respectively.

Results

CCAT2 was significantly elevated in high-grade PDAC tissues and higher CCAT2 expression was correlated with lower survival rate in PDAC patients. CCAT2 was up-regulated in PDAC cell lines, as compared with normal pancreatic cells. Silencing of CCAT2 inhibited cell proliferation and invasion in PANC-1 cells in vitro, and attenuated tumorigenesis of PANC-1 xenograft in vivo. Furthermore, CCAT2 was regulated by KRAS through MEK/ERK signaling pathway.

Conclusions

CCAT2 is an oncogenic lncRNA in PDAC likely regulated by the KRAS-MEK/ERK pathway. It could be a potential diagnostic biomarker and therapeutic target for PDAC.

Pancreatic Cancer Diagnosis and Management: Has the Time Come to Prick the Bubble?

Pancreatic cancer (PC) is associated with poor prognosis and very dismal survival rates. The most effective possibility of cure is tumor resection, which is only possible in about 15% of patients diagnosed at early stages of disease progression. Recent whole-genome sequencing studies pointed genetic alterations in 12 core signaling pathways in PC. These observations hint at the possibility that the initial mutation in PC might appear nearly 20 years before any symptoms occur, suggesting that a large window of opportunity may exist for early detection. Biomarkers with the potential to identify pre-neoplastic disease or very early stages of cancer are of great promise to improve patient survival. The concept of liquid biopsy refers to a minimally invasive sampling and analysis of liquid biomarkers that can be isolated from body fluids, primarily blood, urine and saliva. A myriad of circulating molecules may be useful as tumor markers, including cell-free DNA (cfDNA), cell-free RNA (cfRNA), circulating tumor cells (CTC), circulating tumor proteins, and extracellular vesicles, more specifically exosomes. In this review, we discuss with more detail the potential role of exosomes in several aspects related to PC, from initiation to tumor progression and its applicability in early detection and treatment. Exosomes are small circulating extracellular vesicles of 50-150 nm in diameter released from the plasma membrane by almost all cells and exhibit some advantages over other biomarkers. Exosomes are central players of intercellular communication and they have been implicated in a series of biological process, including tumorigenesis, migration and metastasis. Several exosomal microRNAs and proteins have been observed to distinguish PC from benign pancreatic diseases and healthy controls. Besides their possible role in diagnosis, understanding exosomes functions in cancer has clarified the importance of microenvironment in PC progression as well as its influence in proliferation, metastasis and resistance to chemotherapy. Increasing knowledge on cancer exosomes provides valuable insights on new therapeutic targets and can potentially open new strategies to treat this disease. Continuous research is needed to ascertain the reliability of using exosomes and their content as potential biomarkers, so that, hopefully, in the near future, they will provide the opportunity for early diagnosis, treatment intervention and increase survival of PC patients.

Linc00511 acts as a competing endogenous RNA to regulate VEGFA expression through sponging hsa-miR-29b-3p in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy. Long non-coding RNAs (lncRNAs) are important regulators in pathological processes, yet their potential roles in PDAC are poorly understood. Here, we identify a fundamental role for a novel lincRNA, linc00511, in the progression of PDAC. Linc00511 levels in PDAC tissue specimens and cell lines were examined by quantitative real-time PCR. Corresponding adjacent non-neoplastic tissues were used as controls. The function of linc00511 in PDAC cell lines was determined by RNA interference approach in vitro and in vivo. Fluorescence in situ hybridization (FISH) was used to characterize linc00511 expression in PDAC cells. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were obtained from bioinformatic analysis, luciferase assays and RIP assays. The association between the linc00511/hsa-miR29b-3p axis and VEGFA was verified by Western blotting assay. Immunohistochemistry was performed to evaluate the expression of VEGFA in PDAC samples. The aberrant up-regulation of linc00511 was detected in PDAC cell lines and patient specimens compared with controls. An increase in linc00511 expression indicates the adverse clinical pathological characteristics and poor prognosis. Functionally, linc00511 depletion in PDAC cells decreased proliferation, migration, invasion and endothelial tube formation. Mechanistically, linc00511 could up-regulate VEGFA via its competing endogenous RNA (ceRNA) activity on hsa-miR-29b-3p. In summary, our results define an important axis controlling proliferation, invasion and tumour angiogenesis in PDAC. Linc00511 is a novel lncRNA that plays a significant regulatory role in the pathogenesis and progression of PDAC. Thus, Linc00511 represents a new prognostic biomarker to predict clinical outcome of PDAC patients after surgery and may serve as a potential therapeutic target for PDAC treatment.

A new ETV6-NTRK3 cell line model reveals MALAT1 as a novel therapeutic target - a short report

BACKGROUND

Previously, the chromosomal translocation t(12;15)(p13;q25) has been found to recurrently occur in both solid tumors and leukemias. This translocation leads to ETV6-NTRK3 (EN) gene fusions resulting in ectopic expression of the NTRK3 neurotropic tyrosine receptor kinase moiety as well as oligomerization through the donated ETV6-sterile alpha motif domain. As yet, no in vitro cell line model carrying this anomaly is available. Here we genetically characterized the acute promyelocytic leukemia (APL) cell line AP-1060 and, by doing so, revealed the presence of a t(12;15)(p13;q25). Subsequently, we evaluated its suitability as a model for this important clinical entity.

METHODS

Spectral karyotyping, fluorescence in situ hybridization (FISH), and genomic and transcriptomic microarray-based profiling were used to screen for the presence of EN fusions. qRT-PCR was used for quantitative expression analyses. Responses to AZ-23 (NTRK) and wortmannin (PI3K) inhibitors, as well as to arsenic trioxide (ATO), were assessed using colorimetric assays. An AZ-23 microarray screen was used to define the EN targetome, which was parsed bioinformatically. MAPK1 and MALAT1 activation were assayed using Western blotting and RNA-FISH, respectively, whereas an AML patient cohort was used to assess the clinical occurrence of MALAT1 activation.

RESULTS

An EN fusion was detected in AP1060 cells which, accordingly, turned out to be hypersensitive to AZ-23. We also found that AZ-23 can potentiate the effect of ATO and inhibit the phosphorylation of its canonical target MAPK1. The AZ-23 microarray screen highlighted a novel EN target, MALAT1, which also proved sensitive to wortmannin. Finally, we found that MALAT1 was massively up-regulated in a subset of AML patients.

CONCLUSIONS

From our data we conclude that AP-1060 may serve as a first publicly available preclinical model for EN. In addition, we conclude that these EN-positive cells are sensitive to the NTRK inhibitor AZ-23 and that this inhibitor may potentiate the therapeutic efficacy of ATO. Our data also highlight a novel AML EN target, MALAT1, which was so far only conspicuous in solid tumors.

Current advances of long non-coding RNA highly upregulated in liver cancer in human tumors

Long non-coding RNAs (lncRNAs) are a group of non-coding RNAs (ncRNAs) >200 nucleotides in length that govern diverse biological processes. Recent evidence suggests that lncRNAs are involved in cancer cell proliferation, apoptosis, invasion, migration, and metastasis. Dysregulation of lncRNAs has been observed in various tumors, and lncRNAs act as oncogenes or tumor suppressors in these malignancies. It has been revealed that lncRNA highly upregulated in liver cancer (HULC) is tightly correlated with a number of cancers such as hepatocellular carcinoma, gastric cancer, colorectal cancer, osteosarcoma, and diffuse large B-cell lymphoma. Depletion of HULC suppressed cancer cell proliferation, migration, and invasion and induced apoptosis. Additionally, HULC may function as a diagnostic biomarker and prognostic indicator for some tumors. In this review, we summarize the current knowledge of the role of HULC in cancer progression and the clinical management of human cancers.

rs1859168 A > C polymorphism regulates HOTTIP expression and reduces risk of pancreatic cancer in a Chinese population

BACKGROUND

Long non-coding RNAs (lncRNAs) are aberrantly expressed in many types of human cancer including pancreatic cancer (PC) and correlated with tumorigenesis and cancer prognosis, whereas knowledge about regulatory mechanism of lncRNA expression is few known. This study aimed to explore whether polymorphisms in lncRNAs genes are associated with PC susceptibility by affecting its expression.

METHODS

We first genotyped three common single-nucleotide polymorphisms (SNPs) of lncRNA genes (HOTTIP rs1859168, HOTAIR rs4759314, and H19 rs217727) in 416 paired PC patients and controls, and then validated the results in another 505 paired PC patients and controls. The genotype-phenotype correlation was examined in 50 PC tissue samples with different genotypes as well as by luciferase reporter assay.

RESULTS

In the discovery set, only the HOTTIP rs1859168 A > C showed to be significantly associated with a reduced PC risk (CC vs AA: odds ratio (OR) = 0.71, 95% confidence interval (95%CI) = 0.57-0.88, P = 0.002; recessive model: adjusted OR = 0.51, 95%CI = 0.38-0.68, P < 0.001; additive model: adjusted OR = 0.67, 95%CI = 0.51-0.82, P < 0.001). The results in validation set and pooled population also indicated that the C allele of HOTTIP rs1859168 could significantly decrease the risk of PC. In addition, the genotype-phenotype association analysis suggested that HOTTIP expression level was significantly lower in PC samples with CC genotype than that in samples with AA and AC genotype. Furthermore, the C allele of HOTTIP rs1859168 could significantly decrease the relative luciferase activity compared to the A allele in three PC cell lines.

CONCLUSIONS

The current findings provided evidence that the functional rs1859168 A > C polymorphism may decrease the PC risk by down-regulating the HOTTIP expression.

Long noncoding RNAs expression profile and functional networks in rheumatoid arthritis

The modifying effects of long noncoding RNAs (lncRNAs) in rheumatoid arthritis (RA) recently have drawn much attention; however, the underlying mechanisms remain largely unknown. Herein, we aim to investigate the expression profile of lncRNAs in RA and identify promising targets for RA diagnosis and treatment. Microarray screening and real-time PCR of lncRNAs were performed by use of serum samples from 3 RA patients and 3 healthy controls. Significantly differentially expressed lncRNAs were verified in serum samples from 43 RA patients and 40 healthy controls by real-time PCR. We found that there were 73 up-regulated and 61 down-regulated lncRNAs as well as 128 up-regulated and 37 down-regulated mRNAs in serum samples of RA patients. Validation in RA clinical samples indicated 5 of these lncRNAs were significantly up-regulated including RNA143598, RNA143596, HIX0032090, IGHCgamma1, and XLOC_002730. Significant association was observed between these lncRNAs and the disease course, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) as well as anti-cyclic citrullinated peptide (anti-CCP) antibody. Additionally, 55 of the differentially expressed mRNAs were associated with 41 lncRNAs and were involved in signaling pathways of toll like receptors (TLRs), nuclear factor-kappa B (NF-κB), and cytokine, especially the IRF3/IRF7 mediated signaling transduction. Our study firstly shows the specific profile of lncRNAs in the serum of RA patients and potential signaling pathways involved in RA pathogenesis, which may provide novel targets for the diagnosis and treatment of patients with RA.

Prediction of therapy response in ovarian cancer: Where are we now?

Therapy resistance is a major challenge in the management of ovarian cancer (OC). Advances in detection and new technology validation have led to the emergence of biomarkers that can predict responses to available therapies. It is important to identify predictive biomarkers to select resistant and sensitive patients in order to reduce important toxicities, to reduce costs and to increase survival. The discovery of predictive and prognostic biomarkers for monitoring therapy is a developing field and provides promising perspectives in the era of personalized medicine. This review article will discuss the biology of OC with a focus on targetable pathways; current therapies; mechanisms of resistance; predictive biomarkers for chemotherapy, antiangiogenic and DNA-targeted therapies, and optimal cytoreductive surgery; and the emergence of liquid biopsy using recent studies from the Medline database and ClinicalTrials.gov.

miR-29a-deficiency does not modify the course of murine pancreatic acinar carcinoma

The development of cancers involves the complex dysregulation of multiple cellular processes. With key functions in simultaneous regulation of multiple pathways, microRNA (miR) are thought to have important roles in the oncogenic formation process. miR-29a is among the most abundantly expressed miR in the pancreas. Together with altered expression in pancreatic cancer cell lines and biopsies, and known oncogenic functions in leukemia, this expression data has identified miR-29a as a key candidate for miR involvement in pancreatic cancer biology. Here we used miR-29a-deficient mice and the TAg model of pancreatic acinar carcinoma to functionally test the role of miR-29a in vivo. We found no impact of miR-29a loss on the development or growth of pancreatic tumours, nor on the survival of tumour-bearing mice. These results suggest that, despite differential expression, miR-29a is oncogenically neutral in the pancreatic acinar carcinoma context. If these results are extended to other models of pancreatic cancer, they would reduce the attractiveness of miR-29a as a potential therapeutic target in pancreatic cancer.

miRNA analysis in pancreatic cancer: the Dartmouth experience

Pancreatic cancer is considered one of the most lethal cancers being the fourth leading cause of cancer deaths in adults in the United States because of the lack of early signs and symptoms and the lack of early detection. Pancreatic ductal adenocarcinoma (PDAC) is the most common histological type among pancreatic cancers, representing 80%-90% of all solid tumors of the pancreas. The majority of PDAC develops from three precursor lesions: pancreatic intraepithelial neoplasia, intraductual papillary mucinous neoplasm and mucinous cystic neoplasm. Although histologic tissue evaluation remains the gold standard for diagnosis, endoscopic ultrasound-guided fine needle aspiration has become the preferred modality for obtaining pathologic confirmation. At Dartmouth-Hitchcock Medical Center (DHMC),we have developed and validated a microRNA (miRNA) panel for patients with pancreatic diseases that can be used in association with the gold standard method for diagnosis. miRNAs have an important role in biological processes, such as apoptosis, metabolism, cell growth and differentiation. In cancer, miRNAs can be classified as either oncogenic or tumor suppressor according to their function in the carcinogenic process. In this study, we describe the expression of many miRNA in benign and malignant pancreatic tissues as well as their clinical significance. For this reason, miRNAs have been considered potential biomarkers of pancreatic diseases that could potentially contribute to an early diagnosis, predict disease progression, accurately monitor disease, contribute to better treatment strategies and reduce mortality by improving disease management.

Molecular Drivers of Pancreatic Cancer Pathogenesis: Looking Inward to Move Forward

Pancreatic cancer (PC) continues to rank among the most lethal cancers. The consistent increase in incidence and mortality has made it the seventh leading cause of cancer-associated deaths globally and the third in the United States. The biggest challenge in combating PC is our insufficient understanding of the molecular mechanism(s) underlying its complex biology. Studies during the last several years have helped identify several putative factors and events, both genetic and epigenetic, as well as some deregulated signaling pathways, with implications in PC onset and progression. In this review article, we make an effort to summarize our current understanding of molecular and cellular events involved in the pathogenesis of pancreatic malignancy. Specifically, we provide up-to-date information on the genetic and epigenetic changes that occur during the initiation and progression of PC and their functional involvement in the pathogenic processes. We also discuss the impact of the tumor microenvironment on the molecular landscape of PC and its role in aggressive disease progression. It is envisioned that a better understanding of these molecular factors and the mechanisms of their actions can help unravel novel diagnostic and prognostic biomarkers and can also be exploited for future targeted therapies.

Serological characteristics of autoimmune pancreatitis and its differential diagnosis from pancreatic cancer by using a combination of carbohydrate antigen 19-9, globulin, eosinophils and hemoglobin

Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis, which may be misdiagnosed as pancreatic carcinoma. This study aims to verify new biomarkers for AIP and propose a serological pattern to differentiate AIP from pancreatic adenocarcinoma with routinely performed tests. In this study, data of serum samples were collected and compared between 25 patients with AIP and 100 patients with pancreatic carcinoma. Receiver operating characteristic analysis and logistic regression was performed to evaluate the diagnostic effect of serum parameters in differentiating AIP from pancreatic carcinoma alone or in combination. Among several serum markers observed in the two groups, carbohydrate antigen 19-9 (Ca19-9), globulin, eosinophils and hemoglobin were selected as the independent markers. Serum levels of Globulin, Eosinophil percentage in AIP group were significantly higher than in pancreatic cancer group (P<0.05), while hemoglobin and tumor marker CA19-9 levels were lower (P <0.05). The combination of these markers identified patients with AIP with 92% sensitivity and 79% specificity, which indicated relatively high diagnostic value. Elevated serum eosinophils, globulin, together with decreased hemoglobin level can be used as a preoperative indicator for AIP and can help to initiate diagnosis of AIP in time.