Overexpression of LINC00261 inhibits non-small cell lung cancer cells progression by interacting with miR-522-3p and suppressing Wnt signaling

The role of circular RNAs in autoimmune diseases: Potential diagnostic biomarkers and therapeutic targets

With the emergence of high-quality sequencing technologies, further research on transcriptomes has become possible. Circular RNA (circRNA), a novel type of endogenous RNA molecule with a covalently closed circular structure through "back-splicing," is reported to be widely present in eukaryotic cells and participates mainly in regulating gene and protein expression in various ways. It is becoming a research hotspot in the non-coding RNA field. CircRNA shows close relation to several varieties of autoimmune diseases (AIDs) in both the physiological and pathological level and could potentially be used clinically in terms of diagnosis and treatment. Here, we focus on reviewing the importance of circRNA in various AIDs, with the aim of establishing new biomarkers and providing novel insights into understanding the role and functions of circRNA in AIDs. Specific signaling pathways of how circular RNAs are regulated in AIDs will also be illustrated in this review.

High CASC expression predicts poor prognosis of lung cancer: A systematic review with meta-analysis

BACKGROUND

The long non-coding RNA cancer susceptibility candidate (CASC) has abnormal expression in lung cancer tissues and may correlate with lung cancer prognosis. This study aimed to comprehensively evaluate the association between CASC expression and the cancer prognosis.

METHODS

PubMed, Embase, Web of Science, Google Scholar, Cochrane Library, and China National Knowledge Infrastructure databases were searched until April 1, 2023, to obtain the relevant literature. Studies that met the predefined eligibility criteria were included, and their quality was independently assessed by 2 investigators according to the Newcastle-Ottawa Scale (NOS) score. Detailed information was obtained, such as first author, year of publication, and number of patients. Hazard ratio (HR) with a 95% confidence interval (CI) was extracted and grouped to assess the relationship between CASC expression and cancer prognosis. The dichotomous data was merged and shown as the odds ratio (OR) with a 95% CI was extracted to assess the relationship between CASC expression and clinicopathological parameters.

RESULTS

A total of 12 studies with 746 patients with lung cancer were included in the meta-analysis. The expression levels of lncRNA CASC2 and CASC7 were decreased, while those of CASC9, 11, 15, and 19 were induced in lung cancer tissues compared with paracancerous tissues. In the population with low CASC expression (CASC2 and CASC7), high CASC expression indicated a good lung cancer prognosis (HR = 0.469; 95% CI, 0.271-0.668). Conversely, in the population with high CASC expression (CASC9, 11, 15, and 19), high CASC expression predicted a poor lung cancer outcome (HR = 1.910; 95% CI, 1.628-2.192). High CASC expression also predicted worse disease-free survival (DFS) (HR = 2.803; 95% CI, 1.804-6.319). Combined OR with 95% CI revealed an insignificant positive association between high CASC expression and advanced TNM stage (OR = 1.061; 95% CI, 0.775-1.454), LNM (OR = 0.962; 95% CI, 0.724-1.277), tumor size (OR = 0.942; 95% CI, 0.667-1.330), and histological grade (OR = 1.022; 95% CI, 0.689-1.517).

CONCLUSION

The CASC expression levels negatively correlate with lung cancer prognosis. Therefore, CASC expression may serve as a prognostic marker and a potential therapeutic target for lung cancer.

From carcinogenesis to therapeutic avenues: lncRNAs and mTOR crosstalk in lung cancer

Long non-coding RNAs (lncRNAs) have been demonstrated to have a crucial function in the modulation of the activity of genes, impacting a variety of homeostatic processes involving growth, survival, movement, and genomic consistency. Certain lncRNAs' aberrant expression has been linked to carcinogenesis, tumor growth, and therapeutic resistance. They are beneficial for the management of malignancies since they can function as cancer-causing or cancer-suppressing genes and behave as screening or prognosis indicators. The modulation of the tumor microenvironment, metabolic modification, and spread have all been linked to lncRNAs in lung cancer. Recent research has indicated that lncRNAs may interact with various mTOR signalling systems to control expression in lung cancer. Furthermore, the route can affect how lncRNAs are expressed. Emphasizing the function of lncRNAs as crucial participants in the mTOR pathway, the current review intends to examine the interactions between the mTOR cascade and the advancement of lung cancer. The article will shed light on the roles and processes of a few lncRNAs associated with the development of lung cancer, as well as their therapeutic prospects.

Exosomal-miR-522-3p derived from cancer-associated fibroblasts accelerates tumor metastasis and angiogenesis via repression bone morphogenetic protein 5 in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a gastrointestinal tract malignancy. Exosomes secreted by cancer-associated fibroblasts (CAFs) are reported to participate in tumor progression by delivering noncoding RNA or small proteins. However, the function of exosomal miR-522-3p in CRC remains unclear.

METHODS

CAFs were derived from tumor tissues, and exosomes were identified by western blot or TEM/NTA and originated from CAFs/NFs. The viability, invasion, and migration of HUVECs and CRC cells was examined using MTT, Transwell, and wound healing assays, respectively. The molecular interactions were validated using dual luciferase reporter assay and RIP. Xenograft and lung metastasis mouse models were generated to assess tumor growth and metastasis.

RESULTS

Exosomes extracted from CAFs/NFs showed high expression of CD63, CD81, and TSG101. CAF-derived exosomes significantly increased the viability, angiogenesis, invasion, and migration of HUVECs and CRC cells, thereby aggravating tumor growth, invasion, and angiogenesis in vivo. miR-522-3p was upregulated in CAF-derived exosomes and CRC tissues. Depletion of miR-522-3p reversed the effect of exosomes derived from CAFs in migration, angiogenesis, and invasion of HUVECs and CRC cells. Furthermore, bone morphogenetic protein 5 (BMP5) was identified as a target gene of miR-522-3p, and upregulation of BMP5 reversed the promoting effect of miR-522-3p mimics or CAF-derived exosomes on cell invasion, migration, and angiogenesis of HUVECs and CRC cells.

CONCLUSION

Exosomal miR-522-3p from CAFs promoted the growth and metastasis of CRC through downregulating BMP5, which might provide new strategies for the treatment of CRC.

Comprehensive landscape and future perspective of long noncoding RNAs in non-small cell lung cancer: it takes a village

Long noncoding RNAs (lncRNAs) are a distinct subtype of RNA that lack protein-coding capacity but exert significant influence on various cellular processes. In non-small cell lung cancer (NSCLC), dysregulated lncRNAs act as either oncogenes or tumor suppressors, contributing to tumorigenesis and tumor progression. LncRNAs directly modulate gene expression, act as competitive endogenous RNAs by interacting with microRNAs or proteins, and associate with RNA binding proteins. Moreover, lncRNAs can reshape the tumor immune microenvironment and influence cellular metabolism, cancer cell stemness, and angiogenesis by engaging various signaling pathways. Notably, lncRNAs have shown great potential as diagnostic or prognostic biomarkers in liquid biopsies and therapeutic strategies for NSCLC. This comprehensive review elucidates the significant roles and diverse mechanisms of lncRNAs in NSCLC. Furthermore, we provide insights into the clinical relevance, current research progress, limitations, innovative research approaches, and future perspectives for targeting lncRNAs in NSCLC. By summarizing the existing knowledge and advancements, we aim to enhance the understanding of the pivotal roles played by lncRNAs in NSCLC and stimulate further research in this field. Ultimately, unraveling the complex network of lncRNA-mediated regulatory mechanisms in NSCLC could potentially lead to the development of novel diagnostic tools and therapeutic strategies.

METTL3 promotes the malignancy of non-small cell lung cancer by N6-methyladenosine modifying SFRP2

This study aimed to investigate the roles of METTL3, a regulator of m6A, in NSCLC. RT-qPCR was applied to determine mRNA of m6A-associated genes and SFRP2, and western blot were used for ZEB1 and MMP9 protein expression. Total m6A level was measured using methylated RNA immunoprecipitation (MeRIP) assay, and RIP was used to access m6A level of SFRP2. Cellular behaviors were detected using CCK-8 and tranwell assays. Xenograft assays were conducted to further verify the roles of METTL3 and SFRP2 in NSCLC. The expression level of METTL3 was higher in NSCLC than normal controls. However, downregulation of METTL3 restrained the proliferation, migration and invasion of NSCLC cells. Enhanced expression of METTL3 caused the inverse consequences. Moreover, SFRP2 was found to be negatively regulated by METTL3. Intriguingly, the anti-tumor functions of METTL3 knockdown in the phenotype of NSCLC cells and xenograft mice were overturned by inhibition of SFRP2. Silencing METTL3 resulted in the enhanced stability of SFRP2. Finally, downregulation of SFRP2 induced by METTL3 activated the Wnt/β-catenin signaling pathway in NSCLC. METTL3 acted as an oncogene in the pathogenesis of NSCLC via suppressing SFRP2 to activate Wnt/β-catenin signaling pathway, indicating that METTL3 might be a promising predictor in NSCLC.

The CDK1-Related lncRNA and CXCL8 Mediated Immune Resistance in Lung Adenocarcinoma

Background: Limited therapeutic options are available for advanced LUAD without driver gene mutations. Anti-CDK therapy has shown effectiveness in several kind of cancers, however, the mechanisms still need to be elucidated. Materials and Methods: The lncRNA associated with CDK1 and the immunomodulatory factors that regulate CDK1 were found by bioinformatics analysis and experimental verification. The prognostic model and immune resistance mechanism of lung adenocarcinoma were revealed by single cell analysis, immune infiltration analysis, and signal pathway analysis. Results: LINC00261 was found to be an important CDK1-related lncRNA with a better prognosis in LUAD. In addition, high CDK1 expression indicates a poor immunotherapy response, which may be associated with overexpression of CXCL8. CXCL8 decreased in patients who were immunotherapy-responsive but increased in patients who were immunotherapy-resistant. Signaling pathway analysis suggested that increased CXCL8 and decreased LINC00261 may participate in hypoxia-induced tumor angiogenesis and cause a poor prognosis for the patients. CXCL8 and CDK1 may change G2-M transformation and EMT and promote tumor proliferation. Conclusion: This study explained that LINC00261, CDK1, and CXCL8 may have a mutual regulation relationship, which affects the occurrence of LUAD and the efficacy of immunotherapy.

Murine Falcor/LL35 lncRNA Contributes to Glucose and Lipid Metabolism In Vitro and In Vivo

Glucose and lipid metabolism are crucial functional systems in eukaryotes. A large number of experimental studies both in animal models and humans have shown that long non-coding RNAs (lncRNAs) play an important role in glucose and lipid metabolism. Previously, human lncRNA DEANR1/linc00261 was described as a tumor suppressor that regulates a variety of biological processes such as cell proliferation, apoptosis, glucose metabolism and tumorigenesis. Here we report that murine lncRNA Falcor/LL35, a proposed functional analog of human DEANR1/linc00261, is predominantly expressed in murine normal hepatocytes and downregulated in HCC and after partial hepatectomy. The application of high-throughput approaches such as RNA-seq, LC-MS proteomics, lipidomics and metabolomics analysis allowed changes to be found in the transcriptome, proteome, lipidome and metabolome of hepatocytes after LL35 depletion. We revealed that LL35 is involved in the regulation of glycolysis and lipid biosynthesis in vitro and in vivo. Moreover, LL35 affects Notch and NF-κB signaling pathways in normal hepatocytes. All observed changes result in the decrease in the proliferation and migration of hepatocytes. We demonstrated similar phenotype changes between murine LL35 and human linc00261 depletion in vitro and in vivo that opens the opportunity to translate results for LL35 from a liver murine model to possible functions of human lncRNA linc00261.

The inhibitory effect of LINC00261 upregulation on the pancreatic cancer EMT process is mediated by KLF13 via the mTOR signaling pathway

PURPOSE

The long noncoding RNA LINC00261 was reported to be involved in carcinogenesis and has been validated as a tumor suppressor in pancreatic cancer (PC); however, how LINC00261 is regulated has not been fully examined. Here, we attempted to investigate the upstream and downstream targets of LINC00261 in PC.

METHODS

LINC00261 expression in PC tissues was examined by the Gene Expression Omnibus (GEO) datasets and the Gene Expression Profiling Interactive Analysis (GEPIA) database. The quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were performed to detect the expression level of LINC00261 in PC cells. The location of LINC00261 in PC cells was identified by RNA fluorescence in situ hybridization (RNA-FISH). Cell Counting Kit-8 (CCK-8), cell apoptosis assay, transwell invasion and migration assays testified the critical role of LINC00261 in PC. The luciferase reporter assay was applied to confirm the binding of LINC00261 to its upstream transcription factor KLF13. The changes in LINC00261 related target protein levels were analyzed by Western blotting assay.

RESULTS

LINC00261 was significantly lower in PC tissues and was mainly concentrated in the nucleus. Overexpression of LINC00261 inhibited the invasion and migration of PC cells. Mechanistically, transcription factor KLF13 was confirmed to inhibit the epithelial-mesenchymal transition (EMT) process of PC cells by promoting the transcription of LINC00261 and suppressing the expression of metastasis-associated proteins, such as matrix metalloproteinase MMP2 and vimentin, thus inhibiting the metastasis of PC.

CONCLUSION

LINC00261 regulates PC cell metastasis through the "KLF13-LINC00261-mTOR-P70S6K1-S6" signaling pathway, which provides a significant set of potential PC therapeutic targets.

BigMPI4py: Python Module for Parallelization of Big Data Objects Discloses Germ Layer Specific DNA Demethylation Motifs

Parallelization in Python integrates Message Passing Interface via the mpi4py module. Since mpi4py does not support parallelization of objects greater than 2³¹ bytes, we developed BigMPI4py, a Python module that wraps mpi4py, supporting object sizes beyond this boundary. BigMPI4py automatically determines the optimal object distribution strategy, and uses vectorized methods, achieving higher parallelization efficiency. BigMPI4py facilitates the implementation of Python for Big Data applications in multicore workstations and High Performance Computer systems. We use BigMPI4py to speed-up the search for germ line specific de novo DNA methylated/unmethylated motifs from the 59 whole genome bisulfite sequencing DNA methylation samples from 27 human tissues of the ENCODE project. We developed a parallel implementation of the Kruskall-Wallis test to find CpGs with differential methylation across germ layers. The parallel evaluation of the significance of 55 million CpG achieved a 22x speedup with 25 cores allowing us an efficient identification of a set of hypermethylated genes in ectoderm and mesoderm-related tissues, and another set in endoderm-related tissues and finally, the discovery of germ layer specific DNA demethylation motifs. Our results point out that DNA methylation signal provide a higher degree of information for the demethylated state than for the methylated state. BigMPI4py is available at https://https://www.arauzolab.org/tools/bigmpi4py and https://gitlab.com/alexmascension/bigmpi4py and the Jupyter Notebook with WGBS analysis at https://gitlab.com/alexmascension/wgbs-analysis.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

Linc00261 Inhibited High-Grade Serous Ovarian Cancer Progression through miR-552-ATG10-EMT Axis

In recent years, long non-coding RNAs (lncRNAs) play an important role in a multitude of pathways across species; however, their functions are still unknown. In this study, we demonstrate that Linc00261 is downregulation in high-grade serous ovarian cancer (HGSOC) and can inhibit cell proliferation and migration of high-grade serous ovarian cancer cells. We further validate the targeting interactions among Linc00261, miR-552, and ATG10. Interestingly, they all play important roles for regulating epithelial-mesenchymal transition (EMT) progression. Collectively, these findings suggest that Linc00261, a mediator of EMT progression, can target oncogenic miR-552, elevating ATG10 expression, to prevent high-grade serous ovarian cancer tumorigenesis and may serve as a potential novel therapeutic target.

A Signature of 14 Long Non-Coding RNAs (lncRNAs) as a Step towards Precision Diagnosis for NSCLC

LncRNAs have arisen as new players in the world of non-coding RNA. Disrupted expression of these molecules can be tightly linked to the onset, promotion and progression of cancer. The present study estimated the usefulness of 14 lncRNAs (HAGLR, ADAMTS9-AS2, LINC00261, MCM3AP-AS1, TP53TG1, C14orf132, LINC00968, LINC00312, TP73-AS1, LOC344887, LINC00673, SOX2-OT, AFAP1-AS1, LOC730101) for early detection of non-small-cell lung cancer (NSCLC). The total RNA was isolated from paired fresh-frozen cancerous and noncancerous lung tissue from 92 NSCLC patients diagnosed with either adenocarcinoma (LUAD) or lung squamous cell carcinoma (LUSC). The expression level of lncRNAs was evaluated by a quantitative real-time PCR (qPCR). Based on Ct and delta Ct values, logistic regression and gradient boosting decision tree classifiers were built. The latter is a novel, advanced machine learning algorithm with great potential in medical science. The established predictive models showed that a set of 14 lncRNAs accurately discriminates cancerous from noncancerous lung tissues (AUC value of 0.98 ± 0.01) and NSCLC subtypes (AUC value of 0.84 ± 0.09), although the expression of a few molecules was statistically insignificant (SOX2-OT, AFAP1-AS1 and LOC730101 for tumor vs. normal tissue; and TP53TG1, C14orf132, LINC00968 and LOC730101 for LUAD vs. LUSC). However for subtypes discrimination, the simplified logistic regression model based on the four variables (delta Ct AFAP1-AS1, Ct SOX2-OT, Ct LINC00261, and delta Ct LINC00673) had even stronger diagnostic potential than the original one (AUC value of 0.88 ± 0.07). Our results demonstrate that the 14 lncRNA signature can be an auxiliary tool to endorse and complement the histological diagnosis of non-small-cell lung cancer.

Construction and comprehensive analysis of a competitive endogenous RNA network to reveal potential biomarkers for the malignant differentiation of glioma

BACKGROUND

Long noncoding RNAs (lncRNAs) can act as microRNA (miRNA) sponges to regulate protein-coding gene expression; therefore, lncRNAs are considered major components of the competitive endogenous RNA (ceRNA) network and have attracted growing attention. This study explored the regulatory mechanisms and functional roles of lncRNAs as ceRNAs in the malignant differentiation of low-grade glioma (LGG) to glioblastoma (GBM) and their potential impact on the prognosis of patients with GBM.

METHODS

LncRNA and messenger RNA (mRNA) data were extracted from the Cancer Genome Atlas (TCGA) database from 156 GBM samples and 529 LGG samples. Separately, the miRNA expression data were downloaded from the Gene Expression Omnibus database, with the GSE112009 dataset containing miRNA expression data from 10 GBM samples and 15 LGG samples. Weighted gene coexpression network analysis was performed to screen the glioma grade-related lncRNAs. Then, a ceRNA network was established. The database for annotation, visualization, and integrated discovery was adopted to conduct functional enrichment analysis based on 57 upregulated differentially expressed mRNAs in the ceRNA network. Finally, Kaplan-Meier curves were created for the survival analysis of 13 hub lncRNA by combining the clinical data of GBM patients in TCGA.

RESULTS

A ceRNA network including 16 lncRNAs, 18 miRNAs, and 78 mRNAs specific to the malignant differentiation of LGG to GBM was established. The 57 upregulated differentially expressed mRNAs in the ceRNA network were significantly enriched in 35 gene ontology terms and 5 pathways. The survival analysis showed that 2 lncRNAs (LINC00261 and HOXA10-AS) were prognostic biomarkers for patients with GBM in TCGA.

CONCLUSION

The proposed ceRNA network may help elucidate the regulatory mechanism by which lncRNAs function as ceRNAs and contribute to the malignant differentiation of LGG to GBM. Importantly, the candidate lncRNAs, miRNAs, and mRNAs involved in the ceRNA network can be further evaluated as potential therapeutic targets and prognostic biomarkers for GBM.

Effects of YAP1 and SFRP2 overexpression on the biological behavior of colorectal cancer cells and their molecular mechanisms

Background

Colorectal cancer (CRC) is one of the most common malignancies worldwide and has a high mortality rate. With the development of tumor molecular biology, more and more attention is being paid to the mechanisms of cell pathways in colorectal carcinogenesis, such as the Hippo/Yes-associated protein 1 (YAP1) and Wnt/β-catenin signaling pathways. The abnormal expression of YAP1 and β-catenin have been reported in CRC, and can lead to excessive cell proliferation, and eventually, tumor formation. Secreted frizzled-related protein 2 (SFRP2) levels have been found to be decreased in a variety of cancers, and SFRP2 is an antagonist that binds directly to Wnt signal. At present, the molecular basis of colorectal tumors is still not fully understood. In the present study, we sought to identify the molecular mechanisms underlying YAP1 and SFRP2 in the development of CRC.

Methods

We constructed CRC cell lines that stably overexpressed YAP1 and SFRP2 using lentivirus packaging and cell infection. The levels of expression of the proteins were evaluated by western blot and immunofluorescence assays. Protein complex immunoprecipitation (Co-IP) was used to detect the interaction between YAP1, SFRP2, and β-catenin. The functional roles of YAP1 and SFRP2 in CRC was determined by a Cell Counting Kit-8 (CCK8) proliferation assay and flow cytometric apoptosis assay.

Results

The data of the present study showed that the overexpression of SFRP2 promoted the expression of YAP1 and β-catenin protein, and the overexpression of YAP1 promoted the expression of β-catenin protein. YAP1 overexpression promoted cell proliferation, while SFRP2 overexpression inhibited cell proliferation and promoted cell apoptosis.

Conclusions

Our findings showed that the expression of YAP1, SFRP2, and β-catenin is correlated in CRC cells. The Hippo pathway and Wnt pathway interact with each other in the pathogenesis of CRC, and YAP1 and SFRP2 are involved in the formation and development of CRC.

miR-522 regulates cell proliferation, migration, invasion capacities and acts as a potential biomarker to predict prognosis in triple-negative breast cancer

This study was designed to explore the cell functions and prognostic significance of miR-522 in triple-negative breast cancer. The expression levels of miR-522 in triple-negative breast cancer tissues and cell lines were detected by quantitative real-time PCR analysis. Kaplan-Meier curve and Cox regression analysis were used to investigate the relationship between miR-522 expression and prognosis of patients, and to evaluate the possibility of miR-522 as a potential indicator for predicting the prognosis of triple-negative breast cancer. The CCK-8 and transwell assays were used to assess cell proliferation, migration, and invasion abilities. The expression of miR-522 in triple-negative breast cancer tissues was significantly higher than that in adjacent tissues and its high expression was closely associated with the high incidence of lymph node metastasis, advanced TNM stage, and BRCA1/2 mutation status. High expression of miR-522 is correlated with poor overall survival in patients with triple-negative breast cancer. Besides, functional studies in two triple-negative breast cancer cell lines showed that overexpression of miR-522 significantly promoted cell proliferation, migration, and invasion in vitro. BRCA1 was a potential direct target of miR-522. Our findings indicated that miR-522 was highly expressed in triple-negative breast cancer and was associated with poor prognosis of patients. The upregulation of miR-522 accelerated the progression of triple-negative breast cancer by targeting BRCA1. Therefore, miR-522 provides valuable information for the development of prevention and treatment strategies.

Downregulation of Long Noncoding RNA LINC00261 Attenuates Myocardial Infarction through the miR-522-3p/Trinucleotide Repeat-Containing Gene 6a (TNRC6A) Axis

BACKGROUND

Myocardial infarction (MI) is cardiac tissue necrosis caused by acute and persistent ischemic hypoxia of the coronary arteries. This study is aimed at investigating the expression of long noncoding RNA (lncRNA) LINC00261 in MI and its effect on myocardial cells.

METHODS

qRT-PCR was performed to detect the expression levels of LINC00261, miR-522-3p, and TNRC6A in normal and MI cells. Western blotting analysis was performed to detect the expression of TNRC6A protein. Viability and apoptosis of myocardial cells after MI with the knockout of LINC00261 or TNRC6A were detected. The relationships among miR-522-3p, LINC00261, and TNRC6A in cardiomyocytes were evaluated using a double luciferase reporter gene assay. Hypoxic preconditioning in normal cells was used to construct a simulated MI environment to investigate the effect of LINC00261 on apoptosis of cardiac cells.

RESULTS

LINC00261 and TNRC6A were upregulated, while miR-522-3p was downregulated in coronary heart disease tissues with MI. Knockout of LINC00261 can increase the viability of cardiomyocytes and inhibit cell apoptosis. LINC00261 targets miR-522-3p in cardiomyocytes. In addition, miR-522-3p targets TNRC6A in cardiomyocytes. TNRC6A regulates cell viability and apoptosis of cardiomyocytes after MI, and TNRC6A-induced MI can be reversed by overexpression of miR-522-3p.

CONCLUSIONS

LINC00261 downregulated miR-522-3p in cardiomyocytes after MI by directly targeting miR-522-3p. TNRC6A is the direct target of miR-522-3p. Our results indicated that LINC00261 might serve as a therapeutic target for the treatment of MI.

An Overview of the Role of Long Non-Coding RNAs in Human Choriocarcinoma

Choriocarcinoma (CC), a subtype of trophoblastic disease, is a rare and highly aggressive neoplasm. There are two main CC subtypes: gestational and non-gestational, (so called when it develops as a component of a germ cell tumor or is related to a somatic mutation of a poorly differentiated carcinoma), each with very diverse biological activity. A therapeutic approach is highly effective in patients with early-stage CC. The advanced stage of the disease also has a good prognosis with around 95% of patients cured following chemotherapy. However, advancements in diagnosis and treatment are always needed to improve outcomes for patients with CC. Long non-coding (lnc) RNAs are non-coding transcripts that are longer than 200 nucleotides. LncRNAs can act as oncogenes or tumor suppressor genes. Deregulation of their expression has a key role in tumor development, angiogenesis, differentiation, migration, apoptosis, and proliferation. Furthermore, detection of cancer-associated lncRNAs in body fluids, such as blood, saliva, and urine of cancer patients, is emerging as a novel method for cancer diagnosis. Although there is evidence for the potential role of lncRNAs in a number of cancers of the female genital tract, their role in CC is poorly understood. This review summarizes the current knowledge of lncRNAs in gestational CC and how this may be applied to future therapeutic strategies in the treatment of this rare cancer.

LINC00261: a burgeoning long noncoding RNA related to cancer

Long noncoding RNAs (lncRNAs), are transcripts longer than 200 nucleotides that are considered to be vital regulators of many cellular processes, particularly in tumorigenesis and cancer progression. long intergenic non-protein coding RNA 261 (LINC00261), a recently discovered lncRNA, is abnormally expressed in a variety of human malignancies, including pancreatic cancer, gastric cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, breast cancer, laryngeal carcinoma, endometrial carcinoma, esophageal cancer, prostate cancer, choriocarcinoma, and cholangiocarcinoma. LINC00261 mainly functions as a tumor suppressor that regulates a variety of biological processes in the above-mentioned cancers, such as cell proliferation, apoptosis, motility, chemoresistance, and tumorigenesis. In addition, the up-regulation of LINC00261 is closely correlated with both favorable prognoses and many clinical characteristics. In the present review, we summarize recent research documenting the expression and biological mechanisms of LINC00261 in tumor development. These findings suggest that LINC00261, as a tumor suppressor, has bright prospects both as a biomarker and a therapeutic target.

Fucoidan Inhibits the Progression of Hepatocellular Carcinoma via Causing lncRNA LINC00261 Overexpression

Hepatocellular carcinoma (HCC) as a main type of primary liver cancers has become one of the most deadly tumors because of its high morbidity and poor prognosis. Fucoidan is a family of natural, heparin-like sulfated polysaccharides extracted from brown algae. It is not only a widely used dietary supplement, but also participates in many biological activities, such as anti-oxidation, anti-inflammation and anti-tumor. However, the mechanism of fucoidan induced inhibition of HCC is elusive. In our study, we demonstrated that fucoidan contributes to inhibiting cell proliferation in vivo and in vitro, restraining cell motility and invasion and inducing cell cycle arrest and apoptosis. According to High-Throughput sequencing of long-non-coding RNA (lncRNA) in MHCC-97H cells treated with 0.5 mg/mL fucoidan, we found that 56 and 49 lncRNAs were correspondingly up- and down-regulated. LINC00261, which was related to the progression of tumor, was highly expressed in fucoidan treated MHCC-97H cells. Moreover, knocking down LINC00261 promoted cell proliferation by promoting the expression level of miR-522-3p, which further decreased the expression level of downstream SFRP2. Taken together, our results verified that fucoidan effectively inhibits the progression of HCC via causing lncRNA LINC00261 overexpression.

Bufalin inhibits the malignant development of non-small cell lung cancer by mediating the circ_0046264/miR-522-3p axis

BACKGROUND

Bufalin is an active component of the traditional Chinese medicine "Chan Su" and is reported to play anti-tumor roles in cancer development, but its functional mechanism is largely unclear. This study intends to explore a potential action mode of bufalin in NSCLC.

MATERIALS AND METHODS

The malignant properties of NSCLC, including cell viability, proliferation, adhesion capacity, migration and invasion, were monitored by cell counting kit-8 (CCK-8), adhesion assay and transwell assay, respectively. The expression of circ_0046264 and miR-522-3p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of proliferation- and migration-related markers was examined by western blot. The putative relationship between circ_0046264 and miR-522-3p was verified by dual-luciferase reporter assay, RIP assay and RNA pull-down assay. Animal experiments in nude mice were performed to investigate the role of bufalin in vivo.

RESULTS

Bufalin treatment inhibited cell viability, colony formation, cell adhesion capacity, migration and invasion in NSCLC cells. Bufalin facilitated the expression of circ_0046264, and circ_0046264 overexpression also inhibited NSCLC cell viability, colony formation, cell adhesion capacity, migration and invasion. Besides, circ_0046264 knockdown partially counteracted the effects of bufalin. Further, miR-522-3p was identified as a target of circ_0046264, and its deficiency reversed the effects of circ_0046264 knockdown to suppress malignant activities of NSCLC cells. In addition, bufalin restrained the tumor growth and development in vivo via enhancing the expression of circ_0046264.

CONCLUSION

Bufalin played an anti-tumor role in NSCLC by modulating the circ_0046264/miR-522-3p pathway, which might be a potential functional mechanism of bufalin in NSCLC.

Targeting of ΔNp63α by miR-522 promotes the migration of breast epithelial cells

The TP63 gene, which encodes the p63 protein, is involved in multiple biological processes, including embryonic development and tumorigenesis. ΔNp63α, the predominant isoform of p63 in epithelial cells, acts as an oncogene in early-stage tumors, but paradoxically acts as a potent antimetastatic factor in advanced cancers. Here, we report that ΔNp63α is a direct target of hsa-miR-522 (miR-522). Induced expression of miR-522 reduced the levels of ΔNp63α, predisposing breast epithelial cells to a loss of epithelial and acquisition of mesenchymal morphology, resulting in accelerated collective and single-cell migration. Restoration of ΔNp63α repressed miR-522-induced migration. Interestingly, overexpression of miR-522 did not affect breast epithelial cell proliferation, suggesting that miR-522 acts specifically through ΔNp63α in this context. Furthermore, expression of miR-522-3p and p63 was negatively correlated in human cancer samples. Thus, miR-522 might be a causative factor for breast tumorigenesis and cancer metastasis. In summary, our results reveal a novel miR-522/p63 axis in cell migration and thus suggest a potential strategy for therapeutic treatment of cancer metastasis.

LINC00261 relieves the progression of sepsis-induced acute kidney injury by inhibiting NF-κB activation through targeting the miR-654-5p/SOCS3 axis

Sepsis is a life-threatening disease, which can cause the dysfunction of multiple organs, including kidney. Recently, a number of studies found that the long non-coding RNA (lncRNA) is closely associated with the development and progression of sepsis; however, the role of long intergenic non-protein coding RNA 261 (LINC00261) in sepsis-induced acute kidney injury is poorly understood. In this study, we found the expression of LINC00261 was significantly decreased in the serum of patients with sepsis than healthy controls. A similar result was also observed in the mouse model of sepsis induced by lipopolysaccharide (LPS). Further investigations revealed that overexpression of LINC00261 improved the viability, suppressed the apoptosis and reduced the generation of inflammatory cytokines in LPS-treated HK-2 cells. Mechanistically, we confirmed that LINC00261 could function as a sponge to combine with microRNA-654-5p (miR-654-5p) which inhibits nuclear factor-κB (NF-κB) activity by targeting suppressor of cytokine signaling 3 (SOCS3). In conclusion, our results demonstrate that LINC00261 may regulate the progression of sepsis-induced acute kidney injury via the miR-654-5p/SOCS3/NF-κB pathway and therefore provides a new insight into the treatment of this disease.

DNA methylome profiling identifies novel methylated genes in epithelial ovarian cancer patients with platinum resistance

AIM

Platinum-based chemotherapy is widely used for epithelial ovarian cancer (EOC). As high as 20-25% of EOC patients will not respond to the initial chemotherapy. Accumulated evidences have implied that DNA methylation may serve as a potential bio-marker for chemotherapy-resistant phenotypic screening; however, the pattern underlying primary platinum resistance remains unclear.

METHODS

Reduced representation bisulfite sequencing (RRBS) analysis was performed to identify differences in methylation status between primary platinum-resistant patients Progression free survival (PFS) (PFS < 6 months, n = 8) and extreme sensitive patients (PFS ≥ 24 months, n = 8). The Qubit 3.0 Fluorometer was used for the quantification of RRBS library. The RRBS library was sequenced on Illumina HiSeq2500 sequencer as 50 bp paired-end reads.

RESULTS

After screening, 94 valid hyper-/hypo-methylated regions were identified to be located within 94 gene promoter and exon regions (adjusted q ≤ 0.5), which were primarily associated with cell-cell adhesion, B cell activation and lymphocyte activation according to GO analysis. The 19 differentially methylated regions (DMR) located in the promoter region including TRC-GCA11-1, LOC105370912, ANO7P1, DHX4,MSH2, CDCP2, CCNL1, ARHGAP42P2, PRDM13, LOC101928344, USP29, ZIC5,IL1RAPL1, EVX2, ABR, MGRN1, UBALD1, LINC00261, and ISL2 were identified according to the order of P-values from low to high, of which MSH2, LINC00261, MGRN1, ZIC5, EVX2, CCNL1, and DHX40 were presented to play a variety of roles in cancers process based on the previous studies.

CONCLUSION

DNA methylome profiling based on RRBS assay is an effective method for screening aberrantly methylated genes in primary platinum-resistant patients, which may serve as a potential epigenetic bio-marker for the prediction of primary platinum resistance.

LINC01089 Inhibits Tumorigenesis and Epithelial-Mesenchymal Transition of Non-small Cell Lung Cancer via the miR-27a/SFRP1/Wnt/β-catenin Axis

Long noncoding RNAs (lncRNAs) have emerged as regulators of gene expression and play critical regulatory roles in diverse biological functions and diseases, including cancer. In this study, we report the downregulation of LINC01089 in non-small cell lung cancer (NSCLC) samples, relative to adjacent non-tumor tissues, and demonstrate its role in the inhibition of proliferation, migration, and epithelial–mesenchymal transition (EMT) of NSCLC cells. Mechanistic analysis indicates that LINC01089 acts as a sponge for miR-27a, regulating its expression in NSCLC. Interestingly, LINC01089 mediated the upregulation of SFRP1 expression by inhibiting the Wnt/β-catenin–EMT pathway and inhibiting the epithelial–mesenchymal transition of NSCLC via sponging miR-27a. Overall, our findings highlight LINC01089’s tumorigenic role and regulatory mechanism in NSCLC, thereby suggesting its potential as a therapeutic target for managing NSCLC.

Long non-coding RNA HCG11 sponging miR-522-3p inhibits the tumorigenesis of non-small cell lung cancer by upregulating SOCS5

BACKGROUND

Numerous studies have shown that long non-coding RNA (lncRNA) is involved in various human diseases including non-small cell lung cancer (NSCLC). The aim of this study was to explore the potential role of lncRNA HCG11 in the pathogenesis of NSCLC.

METHODS

The mRNA expression of HCG11, miR-522-3p and SOCS5 was detected by RT-qPCR. The regulatory mechanism of lncRNA HCG11 was investigated by CCK-8, transwell and dual luciferase reporter assays.

RESULTS

Downregulation of lncRNA HCG11 and upregulation of miR-522-3p were found in NSCLC tissues and cells, and abnormal expressions of lncRNA HCG11 and miR-522-3p were related to adverse clinical outcomes of NSCLC patients. LncRNA HCG11 acted as a molecular sponge for miR-522-3p. Functionally, lncRNA HCG11 inhibited cell viability, migration and invasion in NSCLC by downregulating miR-522-3p. Further, miR-522-3p directly targeted SOCS5. lncRNA HCG11 could positively regulate SOCS5 expression in NSCLC. In addition, HCG11 downregulation or miR-522-3p overexpression abolished the inhibitory effect of SOCS5 on cell viability, migration and invasion in NSCLC.

CONCLUSIONS

LncRNA HCG11 inhibits cell viability, migration and invasion in NSCLC by functioning as a ceRNA of miR-522-3p to upregulate SOCS5.

A human ESC-based screen identifies a role for the translated lncRNA LINC00261 in pancreatic endocrine differentiation

Long noncoding RNAs (lncRNAs) are a heterogenous group of RNAs, which can encode small proteins. The extent to which developmentally regulated lncRNAs are translated and whether the produced microproteins are relevant for human development is unknown. Using a human embryonic stem cell (hESC)-based pancreatic differentiation system, we show that many lncRNAs in direct vicinity of lineage-determining transcription factors (TFs) are dynamically regulated, predominantly cytosolic, and highly translated. We genetically ablated ten such lncRNAs, most of them translated, and found that nine are dispensable for pancreatic endocrine cell development. However, deletion of LINC00261 diminishes insulin+ cells, in a manner independent of the nearby TF FOXA2. One-by-one disruption of each of LINC00261's open reading frames suggests that the RNA, rather than the produced microproteins, is required for endocrine development. Our work highlights extensive translation of lncRNAs during hESC pancreatic differentiation and provides a blueprint for dissection of their coding and noncoding roles.

LncRNAs in Non-Small-Cell Lung Cancer

Lung cancer is associated with a high mortality, with around 1.8 million deaths worldwide in 2018. Non-small-cell lung cancer (NSCLC) accounts for around 85% of cases and, despite improvement in the management of NSCLC, most patients are diagnosed at advanced stage and the five-year survival remains around 15%. This highlights a need to identify novel ways to treat the disease to reduce the burden of NSCLC. Long non-coding RNAs (lncRNAs) are non-coding RNA molecules longer than 200 nucleotides in length which play important roles in gene expression and signaling pathways. Recently, lncRNAs were implicated in cancer, where their expression is dysregulated resulting in aberrant functions. LncRNAs were shown to function as both tumor suppressors and oncogenes in a variety of cancer types. Although there are a few well characterized lncRNAs in NSCLC, many lncRNAs remain un-characterized and their mechanisms of action largely unknown. LncRNAs have success as therapies in neurodegenerative diseases, and having a detailed understanding of their function in NSCLC may guide novel therapeutic approaches and strategies. This review discusses the role of lncRNAs in NSCLC tumorigenesis, highlighting their mechanisms of action and their clinical potential.

LncRNA LINC00261 overexpression suppresses the growth and metastasis of lung cancer via regulating miR-1269a/FOXO1 axis

BACKGROUND

LncRNAs are key regulators in cancer. The current study explored the role of lncRNA LINC00261 (LINC00261) in lung cancer (LC).

METHODS

Expression of LINC00261 in LC tissues and cells was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Pearson's Chi square test and Kaplan-Meier analysis were performed to evaluate the correlations between LINC00261 expression and clinical characteristics, and overall survival time. A549 and SPC-A1 cells were transfected with LINC00261 overexpression plasmid, cell viability, cell number, and apoptosis were detected by CCK-8 assay, colony formation, and flow cytometry. Moreover, wound-healing and transwell assay were performed to detect cell metastasis and invasion. Expressions of proteins related to cell proliferation and metastasis were determined by Western blot. Xenograft was constructed, and tumor size and weight were measured and the effects of LINC00261 overexpression on tumor growth were detected. Bioinformatics analysis, dual-luciferase reporter assay, qRT-PCR, correlation analysis, and functional rescue experiments were conducted on clinical cases and LC cells to explore the molecular mechanism of LINC00261 in LC.

RESULTS

In LC, LINC00261 expression was down-regulated, and was associated with more advanced TNM stage, metastasis and a shorter survival time. LINC00261 overexpression inhibited the growth and metastasis of LC cells in vitro and tumor growth in vivo. Furthermore, miR-1269a directly interacted with LINC00261 and FOXO1. The expressions of miR-1269a and FOXO1 were dysregulated by LINC00261 in LC. Additionally, miR-1269a promoted the progression of LC through targeting FOXO1.

CONCLUSIONS

Down-regulation of LINC00261 expression has a prognostic value in LC, and overexpression LINC00261 inhibits LC progression via targeting miR-1269a/FOXO1 axis.

LINC00261 inhibits progression of pancreatic cancer by down-regulating miR-23a-3p

Long noncoding RNAs (lncRNAs) are usually dysregulated in the progression of pancreatic cancer. This research aims to explore the function and mechanism of LINC00261 in pancreatic cancer cell viability, invasion and apoptosis. Cancer Genome Atlas (TCGA) database was applied to analyze the association between survival probability of patients and level of LINC00261 or miR-23a-3p in pancreatic cancer. Quantitative reverse transcription polymerase chain reaction was conducted to analyze the levels of LINC00261 and miR-23a-3p. Cell viability, invasion and apoptosis of pancreatic cancer cells were determined via MTT, transwell invasion assay, and flow cytometry, respectively. The target relationship between LINC00261 and miR-23a-3p was determined via dual-luciferase reporter and RNA immunoprecipitation assays. Low level of LINC00261 indicated low survival probability of pancreatic cancer patients. LINC00261 level was decreased in pancreatic cancer cells than that in normal pancreatic ductal epithelial cells. Addition of LINC00261 restrained cell viability and invasion and facilitated apoptosis. miR-23a-3p was negatively correlated with LINC00261 level and high expression of miR-23a-3p indicated low survival probability. miR-23a-3p was targeted by LINC00261 and attenuated the influence of LINC00261 on pancreatic cancer cell viability, invasion and apoptosis. In conclusion, LINC00261 overexpression repressed cell viability and invasion and enhanced apoptosis by decreasing miR-23a-3p expression in pancreatic cancer cells, indicating a new target for the treatment of pancreatic cancer.

Roles of Wnt/β-Catenin Signaling Pathway Regulatory Long Non-Coding RNAs in the Pathogenesis of Non-Small Cell Lung Cancer

Lung cancer is one of the leading causes of cancer-related mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common pathological type of lung cancer. Long non-coding RNAs (lncRNAs) are promising novel diagnostic and prognostic biomarkers, as well as potential therapeutic targets for lung cancer. Long non-coding RNAs (lncRNAs) have been demonstrated to modulate tumor cells proliferation, cell cycle progression, invasion, and metastasis by regulating gene expression at transcriptional, post-transcriptional, and epigenetic levels. The oncogenic aberrant Wnt/β-catenin signaling is prominent in lung cancer, playing a vital role in tumorigenesis, prognosis, and resistance to therapy. Interestingly, compelling studies have demonstrated that lncRNAs exert either oncogenic or tumor suppressor roles by regulating Wnt/β-catenin signaling. In this review, we aim to present the current accumulated knowledge regarding the roles of Wnt/β-catenin signaling-regulated lncRNAs in the pathogenesis of non-small cell lung cancer (NSCLC). Better understanding of the effects of lncRNAs on Wnt/β-catenin signaling might contribute to the improved understanding of the molecular tumor pathogenesis and to the uncovering of novel therapeutic targets in NSCLC.

Long Noncoding RNA LINC00261 Reduces Proliferation and Migration of Breast Cancer Cells via the NME1-EMT Pathway

Objective

Long noncoding RNAs (lncRNAs) are emerging as a class of important biological regulators. lncRNAs participate in diverse biological functions and disease processes, especially those leading to tumorigenesis. In this study, we investigate the role of linc00261 in the pathogenesis of breast cancer.

Methods

linc00261 and NME1 expression levels were determined in breast cancer tissue and adjacent normal tissue using qRT-PCR. Cell proliferation and migration were analyzed using MTT and transwell assays, respectively. Epithelial–mesenchymal transition markers were examined via Western blotting assay. RNA pull-down was used to examine the interaction between linc00261 and the NME1 mRNA transcript.

Results

linc00261 is expressed in lower levels on breast cancer tissues than in para-carcinoma tissues. Reintroduction of linc00261 can inhibit the migration of breast cancer cells and arrest their proliferation. Additionally, linc00261 knockdown is sufficient to cause breast carcinoma tumorigenesis. We also found that linc00261 interacts with NME1 mRNA, protecting it from degradation. This protection leads to increased cellular levels of NME1, which functions as suppressor of tumor metastasis.

Conclusion

Taken together, these data demonstrate detailed mechanistic links between the linc00261/NME1 axis and tumorigenesis and show that linc00261 might serve as a novel therapeutic target.

Genome-wide analysis of prognostic-related lncRNAs, miRNAs and mRNAs forming a competing endogenous RNA network in lung squamous cell carcinoma

PURPOSE

As a type of cancer with the highest morbidity and mortality, lung squamous cell carcinoma (LUSC) has a very poor prognosis. Long-non-coding RNA (lncRNA) has recently attracted attentions because it can play the role of competing endogenous RNA (ceRNA) to inhibit microRNA (miRNA) functions. In this study, we aimed to find prognosis-related lncRNAs, miRNAs and mRNAs and construct a prognosis-related ceRNA network.

METHODS

The original LUSC RNA-sequencing data and miRNA profiles data were downloaded from the cancer genome atlas (TCGA) database. Differentially expressed lncRNAs, miRNAs and mRNAs were then identified between patients with lymph node metastasis and no lymph node metastasis. Univariate Cox regression analysis was performed to find the survival-associated lncRNAs, miRNAs and mRNAs. Subsequently, prognostic-related ceRNA network was established. By multivariate Cox regression analysis, three lncRNA signatures and three mRNA signatures were developed and used for predicting LUSC patients' survival.

RESULTS

A total of 224 lncRNAs, 160 miRNAs, 913 mRNAs were identified between samples with lymph node metastasis and no lymph node metastasis. Univariate Cox regression analysis showed that, among them, 28 lncRNAs, 8 miRNAs, 105 mRNAs were significantly associated with patients' overall survival time. Further pathway and enrichment analysis suggested that these mRNAs were associated with the regulation of transmembrane transport, regulation of blood circulation, plasma lipoprotein particle organization. Then we constructed a survival-related ceRNA network including 9 lncRNAs, 8 miRNAs and 23 mRNAs. Additionally, a multivariate Cox regression analysis demonstrated that three lncRNAs (AL161431.1, LINC02389, APCDD1L.DT) and three mRNAs (KLK6, SLITRK5, CCDC177) had a significant prognostic value. Risk score indicated that lncRNA signature and mRNA signature could independently predict overall survival in LUSC patients.

CONCLUSION

The current study provided a better understanding of the ceRNA network in the progression of LUSC and laid a theoretical foundation for LUSC prognosis.

Long non-coding RNA LCAL62 / LINC00261 is associated with lung adenocarcinoma prognosis

Background

More than half of non-small cell lung cancer (NSCLC) patients present with metastatic disease at initial diagnosis with an estimated five-year survival rate of ~5%. Despite advances in understanding primary lung cancer oncogenesis metastatic disease remains poorly characterized. Recent studies demonstrate important roles of long non-coding RNAs (lncRNAs) in tumor physiology and as prognostic markers. Therefore, we present the first transcriptome analysis to identify lncRNAs altered in metastatic lung adenocarcinoma leading to the discovery and characterization of the lncRNA LCAL62 as a prognostic biomarker.

Patients and methods

RNA-Seq, microarray, nanoString expression, and clinical data from 1,116 LUAD patients across six independent cohorts and 83 LUAD cell lines were used to discover and evaluate the survival association of metastasis associated lncRNAs. Coexpression and gene set enrichment analyses were used to establish gene regulatory networks and implicate metastasis associated lncRNAs in specific biological processes.

Results

Our integrative analysis discovered LCAL62 as the most down-regulated lncRNA in metastasis. Further low LCAL62 expression promoted aggressive phenotypes and regulated genes associated with metastasis (such as metastasis repressor FOXA2). Low LCAL62 expression corresponded to poor overall patient survival across five independent lung adenocarcinoma cohorts (n = 881) including our own nanoString validation cohort.

Conclusion

We discovered that LCAL62 was down-regulated in lung cancer progression to promote invasive phenotypes, and lower expression was significantly associated with poor patient outcome and aggressive lung adenocarcinoma.

CAF secreted miR-522 suppresses ferroptosis and promotes acquired chemo-resistance in gastric cancer

BACKGROUND

Ferroptosis is a novel mode of non-apoptotic cell death induced by build-up of toxic lipid peroxides (lipid-ROS) in an iron dependent manner. Cancer-associated fibroblasts (CAFs) support tumor progression and drug resistance by secreting various bioactive substances, including exosomes. Yet, the role of CAFs in regulating lipid metabolism as well as ferroptosis of cancer cells is still unexplored and remains enigmatic.

METHODS

Ferroptosis-related genes in gastric cancer (GC) were screened by using mass spectrum; exosomes were isolated by ultra-centrifugation and CAF secreted miRNAs were determined by RT-qPCR. Erastin was used to induce ferroptosis, and ferroptosis levels were evaluated by measuring lipid-ROS, cell viability and mitochondrial membrane potential.

RESULTS

Here, we provide clinical evidence to show that arachidonate lipoxygenase 15 (ALOX15) is closely related with lipid-ROS production in gastric cancer, and that exosome-miR-522 serves as a potential inhibitor of ALOX15. By using primary stromal cells and cancer cells, we prove that exosome-miR-522 is mainly derived from CAFs in tumor microenvironment. Moreover, heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) was found to mediate miR-522 packing into exosomes, and ubiquitin-specific protease 7 (USP7) stabilizes hnRNPA1 through de-ubiquitination. Importantly, cisplatin and paclitaxel promote miR-522 secretion from CAFs by activating USP7/hnRNPA1 axis, leading to ALOX15 suppression and decreased lipid-ROS accumulation in cancer cells, and ultimately result in decreased chemo-sensitivity.

CONCLUSIONS

The present study demonstrates that CAFs secrete exosomal miR-522 to inhibit ferroptosis in cancer cells by targeting ALOX15 and blocking lipid-ROS accumulation. The intercellular pathway, comprising USP7, hnRNPA1, exo-miR-522 and ALOX15, reveals new mechanism of acquired chemo-resistance in GC.

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

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

Long noncoding RNA VPS9D1-AS1 augments the malignant phenotype of non-small cell lung cancer by sponging microRNA-532-3p and thereby enhancing HMGA2 expression

We investigated the influence of the long noncoding RNA VPS9D1 antisense RNA 1 (VPS9D1-AS1) on the malignant phenotype of non-small cell lung cancer (NSCLC) cells in vitro and in vivo. We also explored the mechanisms by which VPS9D1-AS1 exerts its oncogenic action during NSCLC progression. VPS9D1-AS1 expression was upregulated in NSCLC; the extent of its upregulation significantly correlated with patients’ adverse clinicopathological characteristics and shorter overall survival. When VPS9D1-AS1 was knocked down in NSCLC cells, their proliferation, colony-forming capacity, migration, and invasiveness were lower, whereas their apoptosis rate was higher, compared to the control. VPS9D1-AS1 knockdown attenuated tumor growth of NSCLC cells in vivo. Mechanistically, VPS9D1-AS1 directly interacted with microRNA-532-3p (miR-532-3p) in NSCLC cells; the impact of VPS9D1-AS1 knockdown on NSCLC cells was attenuated by miR-532-3p inhibition. Furthermore, VPS9D1-AS1 knockdown decreased the expression of high mobility group AT-hook 2 (HMGA2) in NSCLC cells via miR-532-3p sponging. Recovery of HMGA2 expression partially reversed the inhibitory effects of VPS9D1-AS1 knockdown on NSCLC cells. Thus, VPS9D1-AS1 functions as a competing endogenous RNA that positively regulates HMGA2 expression by sponging miR-532-3p in NSCLC cells, suggesting that the VPS9D1-AS1–miR-532-3p–HMGA2 pathway can be a potential diagnostic and/or therapeutic target in NSCLC.

Circ_0000003 promotes the proliferation and metastasis of non-small cell lung cancer cells via miR-338-3p/insulin receptor substrate 2

Background: Circular RNAs (circRNAs) play a pivotal regulatory role in a variety of tumors.Nevertheless, the detailed function of circ_0000003 in non-small cell lung cancer (NSCLC) and its regulatory mechanism remain elusive.Methods: RT-PCR was carried out to detect the expressions of circ_0000003, miR-338-3p and insulin receptor substrate 2 (IRS2)in NSCLC tissues. Besides, western blot was done to monitor IRS2 expression in NSCLC cells. The correlation between circ_0000003 and clinicopathologic characteristics of NSCLC patients was analyzed as well.CCK8 and BrdUassays were used to monitor cell proliferation; flow cytometry was used to detect apoptosis; and transwell assay was conducted to detect its migration and invasion.Moreover, dual luciferase reporter gene assay was done to verify the targeting relationship between circ_0000003 and miR-338-3p.Additionally, the effect of circ_0000003 on the growth of NSCLC cells in vivo was evaluated by tumorigenesis assay in nude mice.Results: The expression of circ_0000003 was significantly high in NSCLC tissues and cell lines, and its high expression level was notably correlated with lymph node metastasis andTNM staging.In vitro experiments showed that overexpression of circ_0000003 facilitated the proliferation, migration, invasion and inhibited the apoptosis of NSCLC cells, while the knockdown of circ_0000003 had the opposite effect.In vivo experiments revealed that knockdown of circ_0000003 impeded tumor growth and metastasis. Further, the underlying mechanism showed that circ_0000003 functioned as endogenous competitive RNA and directly targeted miR-338-3p to positively regulated IRS2 expression.Conclusion: Circ_0000003 promotes the proliferation and metastasis of NSCLC cells via modulating miR-338-3p/IRS2 axis.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.