Hypoxia-sensitive LINC01436 is regulated by E2F6 and acts as an oncogene by targeting miR-30a-3p in non-small cell lung cancer

Regulation of the HIF switch in human endothelial and cancer cells

Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.

circ_PPAPDC1A promotes Osimertinib resistance by sponging the miR-30a-3p/ IGF1R pathway in non-small cell lung cancer (NSCLC)

BACKGROUND

Recent evidence has demonstrated that abnormal expression and regulation of circular RNA (circRNAs) are involved in the occurrence and development of a variety of tumors. The aim of this study was to investigate the effects of circ_PPAPDC1A in Osimertinib resistance in NSCLC.

METHODS

Human circRNAs microarray analysis was conducted to identify differentially expressed (DE) circRNAs in Osimertinib-acquired resistance tissues of NSCLC. The effect of circ_PPAPDC1A on cell proliferation, invasion, migration, and apoptosis was assessed in both in vitro and in vivo. Dual-luciferase reporter assay, RT-qPCR, Western-blot, and rescue assay were employed to confirm the interaction between circ_PPAPDC1A/miR-30a-3p/IGF1R axis.

RESULTS

The results revealed that circ_PPAPDC1A was significantly upregulated in Osimertinib acquired resistance tissues of NSCLC. circ_PPAPDC1A reduced the sensitivity of PC9 and HCC827 cells to Osimertinib and promoted cell proliferation, invasion, migration, while inhibiting apoptosis in Osimertinib-resistant PC9/OR and HCC829/OR cells, both in vitro and in vivo. Silencing circ_PPAPDC1A partially reversed Osimertinib resistance. Additionally, circ_PPAPDC1A acted as a competing endogenous RNA (ceRNA) by targeting miR-30a-3p, and Insulin-like Growth Factor 1 Receptor (IGF1R) was identified as a functional gene for miR-30a-3p in NSCLC. Furthermore, the results confirmed that circ_PPAPDC1A/miR-30a-3p/IGF1R axis plays a role in activating the PI3K/AKT/mTOR signaling pathway in NSCLC with Osimertinib resistance.

CONCLUSIONS

Therefore, for the first time we identified that circ_PPAPDC1A was significantly upregulated and exerts an oncogenic role in NSCLC with Osimertinib resistance by sponging miR-30a-3p to active IGF1R/PI3K/AKT/mTOR pathway. circ_PPAPDC1A may serve as a novel diagnostic biomarker and therapeutic target for NSCLC patients with Osimertinib resistance.

E2F7 serves as a potential prognostic biomarker for lung adenocarcinoma

E2F transcription factors (E2Fs) are a family of transcription factors critical regulators of the cell cycle, apoptosis, and differentiation, thus influencing tumorigenesis. However, the specific roles of E2Fs in lung adenocarcinoma (LUAD) remain unclear. Data from The Cancer Genome Atlas (TCGA) were used. R version. 4.0.3 and multiple databases (TIMER, cBioportal, gene expression profile interaction analysis [GEPIA], LinkedOmics, and CancerSEA) were utilized to investigate mRNA expression, mutational analysis, prognosis, clinical correlations, co-expressed gene, pathway and network, and single-cell analyses. Immunohistochemistry (IHC) confirmed that E2F transcription factor 7 (E2F7) correlated with LUAD. Among the E2Fs, E2F7 was identified by constructing a prognostic model most significantly associated with overall survival (OS) in LUAD patients. The univariate and multivariate Cox regression analyses showed that E2F7, p-T stage, and p-TNM stage were closely related to OS and progression-free survival (PFS) (P < .05) in LUAD. E2F 7/8 were also identified as significantly associated with tumor stage in the GEPIA database. Compared with paracancerous tissues, E2F7 was up-regulated in LUAD by IHC, and E2F7 might be positively correlated with larger tumors and higher TNM stages. E2F7 may primarily regulate DNA repair, damage, and cell cycle processes and thus affect LUAD tumorigenesis, invasion, and metastasis by LinkedOmics and CancerSEA. E2F7 serves as a potential prognostic biomarker for LUAD.

Downregulation of N6-methyladenosine-modified LINC00641 promotes EMT, but provides a ferroptotic vulnerability in lung cancer

The prognosis of lung cancer is poor with few effective therapies. Targeting ferroptosis is a new promising strategy for cancer therapy. LINC00641 has been involved in several cancers, however, its specific roles in lung cancer treatment remain largely unknown. Here, we reported that LINC00641 was down-regulated in tumor tissues and its downregulation was associated with poor outcomes in lung adenocarcinoma. LINC00641 was localized primarily in the nucleus and was modified by m⁶A. The nuclear m⁶A reader YTHDC1 regulated LINC00641 expression by affecting its stability. We demonstrated that LINC00641 suppressed lung cancer by inhibiting migration and invasion in vitro and metastasis in vivo. Knockdown of LINC00641 upregulated HuR protein level (especially in the cytoplasm), which subsequently increased N-cadherin levels by stabilizing its mRNA, then ultimately promoted EMT. Interestingly, LINC00641 knockdown in lung cancer cells increased the arachidonic acid metabolism and promoted ferroptosis sensitivity. Our findings identified LINC00641 as a tumor suppressor through inhibiting EMT. In another aspect, low expression of LINC00641 caused a ferroptotic vulnerability in lung cancer cells, which may serve as a potential ferroptosis-related therapeutic target for lung cancer.

Integrated analysis of competitive endogenous RNA networks in elder patients with non-small cell lung cancer

BACKGROUND

Lung cancer is one of the most prevalent cancers and the leading cause of cancer-related deaths worldwide; non-small cell lung cancer (NSCLC) comprises approximately 80% of all lung cancer cases. This study aimed to construct a competing endogenous RNA (ceRNA) network and identify prognostic signatures in elderly patients with NSCLC.

METHODS

We extracted data from elderly patients with NSCLC from The Cancer Genome Atlas and identified differentially expressed (DE) messenger RNAs (mRNAs), microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to investigate the functions of DEmRNAs. The interactions between RNAs were predicted using starBase, TargetScan, miRTarBase, and miRanda. Cytoscape version 3.0 was used to construct and visualize the lncRNA-miRNA-mRNA ceRNA network. The association between the expression levels of DERNAs in the constructed ceRNA network and overall survival was determined using the survival package in R software. Furthermore, another Gene Expression Omnibus cohort was studied to externally validate the ceRNA network.

RESULTS

In total, 2865 DEmRNAs, 62 DEmiRNAs, and 131 DElncRNAs were identified. Dysregulated mRNAs are enriched in cancer-related processes and pathways. A ceRNA network was constructed using 38 miRNAs, 61 lncRNAs, and 164 mRNAs. Of these, 3 lncRNAs, 3 miRNAs, and 16 mRNAs were closely related to overall survival. The MIR99AHG-hsa-miR-31-5p-PRKCE axis has been identified as a potential ceRNA network involved in the development of NSCLC in elderly individuals. External validation of the MIR99AHG-hsa-miR-31-5p-PRKCE axis in the GSE19804 cohort showed that PRKCE was downregulated and that MIR99AHG was upregulated in the tumor tissues of elderly patients with NSCLC compared with normal lung tissues.

CONCLUSIONS

This study provides novel insights into the lncRNA-miRNA-mRNA ceRNA network and reveals potential biomarkers for the diagnosis and prognosis of elderly patients with NSCLC.

Interaction Among Noncoding RNAs, DNA Damage Reactions, and Genomic Instability in the Hypoxic Tumor: Is it Therapeutically Exploitable Practice?

Hypoxia is a classical function of the tumor's microenvironment with a substantial effect on the development and therapeutic response of cancer. When put in hypoxic environments, cells undergo several biological reactions, including activation of signaling pathways that control proliferation, angiogenesis, and death. These pathways have been adapted by cancer cells to allow tumors to survive and even develop in hypoxic conditions, and poor prognosis is associated with tumor hypoxia. The most relevant transcriptional regulator in response to hypoxia, Hypoxia-inducible factor-1 alpha (HIF-1α), has been shown to modulate hypoxic gene expression and signaling transduction networks significantly. The significance of non-coding RNAs in hypoxic tumor regions has been revealed in an increasing number of studies over the past few decades. In regulating hypoxic gene expression, these hypoxia-responsive ncRNAs play pivotal roles. Hypoxia, a general characteristic of the tumor's microenvironment, significantly affects the expression of genes and is closely associated with the development of cancer. Indeed, the number of known hypoxia-associated lncRNAs has increased dramatically, demonstrating the growing role of lncRNAs in cascades and responses to hypoxia signaling. Decades of research have helped us create an image of the shift in hypoxic cancer cells' DNA repair capabilities. Emerging evidence suggests that hypoxia can trigger genetic instability in cancer cells because of microenvironmental tumor stress. Researchers have found that critical genes' expression is coordinately repressed by hypoxia within the DNA damage and repair pathways. In this study, we include an update of current knowledge on the presentation, participation, and potential clinical effect of ncRNAs in tumor hypoxia, DNA damage reactions, and genomic instability, with a specific emphasis on their unusual cascade of molecular regulation and malignant progression induced by hypoxia.

The functions of long noncoding RNAs on regulation of F-box proteins in tumorigenesis and progression

Accumulated evidence has revealed that F-box protein, a subunit of SCF E3 ubiquitin ligase complexes, participates in carcinogenesis and tumor progression via targeting its substrates for ubiquitination and degradation. F-box proteins could be regulated by cellular signaling pathways and noncoding RNAs in tumorigenesis. Long noncoding RNA (lncRNA), one type of noncoding RNAs, has been identified to modulate the expression of F-box proteins and contribute to oncogenesis. In this review, we summarize the role and mechanisms of multiple lncRNAs in regulating F-box proteins in tumorigenesis, including lncRNAs SLC7A11-AS1, MT1JP, TUG1, FER1L4, TTN-AS1, CASC2, MALAT1, TINCR, PCGEM1, linc01436, linc00494, GATA6-AS1, and ODIR1. Moreover, we discuss that targeting these lncRNAs could be helpful for treating cancer via modulating F-box protein expression. We hope our review can stimulate the research on exploration of molecular insight into how F-box proteins are governed in carcinogenesis. Therefore, modulation of lncRNAs is a potential therapeutic strategy for cancer therapy via regulation of F-box proteins.

Comprehensive Analysis of the E2F Transcription Factor Family in Human Lung Adenocarcinoma

Background

E2F transcription factors (E2Fs), code a family of pivotal transcription factors, have been identified as key regulators in tumor tumorigenesis. However, the function of E2F family in human lung adenocarcinoma (LUAD) have not been fully elucidated.

Methods

Herein, The Cancer Genome Atlas (TCGA) databases, Kaplan-Meier plotter, cBioPortal and TIMER were used to analyze differential expression, prognostic value, genetic alteration and immune cell infiltration of E2Fs in LUAD patients.

Results

The expression levels of E2Fs (E2F1-8) were all significantly upregulated in LUAD tissues compared with normal lung tissues. All eight E2Fs had low rates of gene mutation in LUAD patients from cBioPortal databases. Survival analysis revealed that E2F2 (P=0.038; HR 1.36; 95% CI 1.02–1.81), E2F7 (P<0.001; HR 1.78; 95% CI 1.33–2.39) and E2F8 (P=0.03; HR 1.37; 95% CI 1.02–1.82) were significantly associated with poor prognosis. Multivariate cox regression analysis found that only E2F7 (P<0.001; HR 2.72; 95% CI 1.75–4.25) was an independent prognostic predictor in LUAD after adjusting common clinical parameters. The receiver operating characteristic (ROC) analysis also found that E2F7 had high diagnostic value for LUAD (AUC=0.901). Further analysis found that E2F7 was significantly associated with LUAD immune cell infiltration of B cell, T cell, neutrophil, and myeloid dendritic cell. E2F7 also have positive correlations with immune checkpoint genes including SIGLEC15, CD274, HAVCR2, PDCD1LG2, CTLA4, TIGIT, LAG3 and PDCD1 in LUAD.

Conclusion

Our findings showed various association of E2F7 in LUAD diagnostic and prognostic aspects, which suggested its potential in becoming a novel biomarker.

The Hypoxic Landscape Stratifies Gastric Cancer Into 3 Subtypes With Distinct M6a Methylation and Tumor Microenvironment Infiltration Characteristics

The interaction between hypoxia and RNA N6-methyladenosine (m6A) is an emerging focus of investigation. However, alterations in m6A modifications at distinct hypoxia levels remain uncharacterized in gastric cancer (GC). Unsupervised hierarchical clustering was performed to stratify samples into different clusters. Differentially expressed gene analysis, univariate Cox proportional hazards regression analysis, and hazard ratio calculations were used to establish an m6A score to quantify m6A regulator modification patterns. After using an algorithm integrating Least absolute shrinkage and selection operator (LASSO) and bootstrapping, we identified the best candidate predictive genes. Thence, we established an m6A-related hypoxia pathway gene prognostic signature and built a nomogram to evaluate its predictive ability. The area under the curve (AUC) value of the nomogram was 0.811, which was higher than that of the risk score (AUC=0.695) and stage (AUC=0.779), suggesting a high credibility of the nomogram. Furthermore, the clinical response of anti-PD-1/CTLA-4 immunotherapy between high- and low-risk patients showed a significant difference. Our study successfully explored a brand-new GC pathological classification based on hypoxia pathway genes and the quantification of m6A modification patterns. Comprehensive immune analysis and validation demonstrated that hypoxia clusters were reliable, and our signature could provide a new approach for clinical decision-making and immunotherapeutic strategies for GC patients.

Identification of Potential Predictor of Biochemical Recurrence in Prostate Cancer

Background

Prostate cancer is a common malignancy in men. Radical prostatectomy is one of the primary treatment modalities for patients with prostate cancer. However, early identification of biochemical recurrence is a major challenge for post-radical prostatectomy surveillance. There is a lack of reliable predictors of biochemical recurrence. The purpose of this study was to explore potential biochemical recurrence indicators for prostate cancer.

Materials and Methods

We analyzed transcriptomic data of cases with biochemical recurrence in The Cancer Genome Atlas (TCGA). Then, we performed integrative bioinformatics analyses to establish a biochemical recurrence predictor model of prostate cancer.

Results

There were 146 differentially expressed genes (DEGs) between prostate cancer and normal prostate, including 12 upregulated and 134 downregulated genes. Comprehensive pathway enrichment analyses revealed that these DEGs were associated with multiple cellular metabolic pathways. Subsequently, according to the random assignment principle, 208 patients were assigned to the training cohort and 205 patients to the validation cohort. Univariate Cox regression analysis showed that 7 genes were significantly associated with the biochemical recurrence of prostate cancer. A model consisting of 5 genes was constructed using LASSO regression and multivariate Cox regression to predict biochemical recurrence of prostate cancer. Expression of PAH and AOC1 decreased with an increasing incidence of prostate cancer, whereas expression of DDC, LINC01436 and ORM1 increased with increasing incidence of prostate cancer. Kaplan–Meier curves and receiver operator characteristic (ROC) curves indicated that the 5-gene model had reliable utility in identifying the risk of biochemical recurrence of prostate cancer.

Conclusion

This study provides a model for predicting prostate cancer recurrence after surgery, which may be an optional indicator for postoperative follow-up.

DesA Prognostic Risk Model of LncRNAs in Patients With Acute Myeloid Leukaemia Based on TCGA Data

Purpose: This study aimed to combine the clinical data of acute myeloid leukaemia (AML) from The Cancer Genome Atlas (TCGA) database to obtain prognosis-related biomarkers, construct a prognostic risk model using long non-coding RNAs (lncRNAs) in AML and help patients with AML make clinical treatment decisions.

Methods: We analysed the transcriptional group information of 151 patients with AML obtained from TCGA and extracted the expressions of lncRNAs. According to the mutation frequency, the patients were divided into the high mutation group (genomic unstable group, top 25% of mutation frequency) and low mutation group (genomic stable group, 25% after mutation frequency). The ‘limma’ R package was used to analyse the difference in lncRNA expressions between the two groups, and the “survival,” “caret,” and “glmnet” R packages were used to screen lncRNAs that are related to clinical prognosis. Subsequently, a prognosis-related risk model was constructed and verified through different methods.

Results: According to the lncRNA expression data in TCGA, we found that seven lncRNAs (i.e. AL645608.6, LINC01436, AL645608.2, AC073534.2, LINC02593, AL512413.1, and AL645608.4) were highly correlated with the clinical prognosis of patients with AML, so we constructed a prognostic risk model of lncRNAs based on LINC01436, AC073534.2, and LINC02593. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of differentially expressed lncRNA-related target genes were performed, receiver operating characteristic (ROC) curves were created, the applicability of the model in children was assessed using the TARGET database and the model was externally verified using the GEO database. Furthermore, different expression patterns of lncRNAs were validated in various AML cell lines derived from Homo sapiens.

Conclusions: We have established a lncRNA prognostic model that can predict the survival of patients with AML. The Kaplan-Meier analysis showed that this model distinguished survival differences between patients with high- and low-risk status. The ROC analysis confirmed this finding and showed that the model had high prediction accuracy. The Kaplan-Meier analysis of the clinical subgroups showed that this model can predict prognosis independent of clinicopathological factors. Therefore, the proposed prognostic lncRNA risk model can be used as an independent biomarker of AML.

An integrated analysis of the competing endogenous RNA network associated of prognosis of stage I lung adenocarcinoma

Background

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) are involving in the tumorigenesis and metastasis of lung cancer. The aim of the study is to systematically characterize the lncRNA-associated competing endogenous RNA (ceRNA) network and identify key lncRNAs in the development of stage I lung adenocarcinoma (LUAD).

Methods

Totally, 1,955 DEmRNAs, 165 DEmiRNAs and 1,107 DElncRNAs were obtained in 10 paired normal and LUAD tissues. And a total of 8,912 paired lncRNA-miRNA-mRNA network was constructed. Using the Cancer Genome Atlas (TCGA) dataset, the module of ME turquoise was revealed to be most relevant to the progression of LUAD though Weighted Gene Co-expression Network Analysis (WGCNA).

Results

Of the lncRNAs identified, LINC00639, RP4-676L2.1 and FENDRR were in ceRNA network established by our RNA-sequencing dataset. Using univariate Cox regression analysis, FENDRR was a risk factor of progression free survival (PFS) of stage I LUAD patients (HRs = 1.69, 95%CI 1.07–2.68, P < .050). Subsequently, diffe rential expression of FENDRR in paired normal and LUAD tissues was detected significant by real-time quantitative (qRT-PCR) (P < 0.001).

Conclusions

This study, for the first time, deciphered the regulatory role of FENDRR/miR-6815-5p axis in the progression of early-stage LUAD, which is needed to be established in vitro and in vivo.

LINC 01436 is overexpressed in colorectal cancer and promotes cancer cell proliferation by suppressing tumor-suppressive miR-466 maturation

LINC 01436 (lncRNA) promotes lung and gastric cancers. However, it is unclear whether it participates in colorectal cancer (CRC) progression. Therefore, the study was carried out to analyze the role of LINC 01436 in CRC. LINC 01436 expressions in CRC tissues were analyzed by RT-qPCR, and its prognostic value was investigated in a follow-up study. Correlation between LINC 01436 and mature miR-466 or miR-466 precursor was analyzed by linear regression. Mature miR-466 and miR-466 precursor levels in CRC cells with LINC 01436 overexpression were studied using RT-qPCR. CRC cell proliferation was evaluated using CCK-8 assay. LINC 01436 was upregulated in CRC and predicted poor survival. LINC 01436 was inversely correlated with mature miR-466, but not miR-466 precursor. LINC 01436 was predicted to bind with miR-466 precursor. Their interaction was further verified by dual-luciferase activity assay. In CRC cells, LINC 01436 overexpression downregulated mature miR-466 but not miR-466 precursor. Cell proliferation analysis showed that LINC 01436 overexpression rescued cell proliferation reduced by miR-466. LINC 01436 is overexpressed in CRC and promotes cancer cell proliferation by suppressing miR-466 maturation.

New Insights into the Importance of Long Non-Coding RNAs in Lung Cancer: Future Clinical Approaches

In mammals, a large part of the gene expression products come from the non-coding ribonucleotide sequences of the protein. These short and long sequences are within the range of tens to hundreds of nucleotides, encompassing more than 200 RNA molecules, and their function is known as the molecular structure of long non-coding RNA (lncRNA). LncRNA molecules are unique nucleotides that have a substantial role in epigenetic regulation, transcription, and post-transcriptional modifications in different ways. According to the results of recent studies, lncRNAs have been shown to assume various roles, including tumor suppression or oncogenic functions in common types of cancer such as lung and breast cancer. These non-coding RNAs (ncRNAs) play a pivotal role in activating transcription factors, managing the ribonucleoproteins, the framework for collecting co-proteins, intermittent processing regulations, chromatin status alterations, and maintaining the control within the cell. Cutting-edge technologies have been introduced to disclose several types of lncRNAs within the nucleus and the cytoplasm, which have accomplished important achievements that are applicable in medicine. Due to these efforts, various data centers have been created to facilitate and modify scientific information related to these molecules, including detection, classification, biological evolution, gene status, spatial structure, status, and location of these small molecules. In the present study, we attempt to present the impacts of these ncRNAs on lung cancer with an emphasis on their mechanisms and functions.

A Novel Assessment Model Based on Molecular Subtypes of Hypoxia-Related LncRNAs for Prognosis of Bladder Cancer

Hypoxia is a common feature in various tumors that regulates aggressiveness. Previous studies have demonstrated that some dysregulated long non-coding RNAs (lncRNAs) are correlated with tumor progression, including bladder cancer (BCa). However, the prognostic effect of hypoxia-related lncRNAs (HRLs) and their clinical relevance, as well as their regulatory effect on the tumor immune microenvironment, are largely unknown in BCa. A co-expression analysis between hypoxia genes and lncRNA expression, which was downloaded from the TCGA database, was performed to identify HRLs. Univariate Cox regression analysis was performed to select the most desirable lncRNAs for molecular subtype, and further LASSO analysis was performed to develop a prognostic model. This molecular subtype based on four HRLs (AC104653, AL136084, AL139393, and LINC00892) showed good performance in the tumor microenvironment and tumor mutation burden. The prognostic risk model suggested better performance in predicting BCa patients' prognosis and obtained a close correlation with clinicopathologic features. Furthermore, four of five first-line clinical chemotherapies showed different sensitivities to this model, and nine immune checkpoints showed different expression in the molecular subtypes or the risk model. In conclusion, this study indicates that this molecular subtype and risk model based on HRLs may be useful in improving the prognostic prediction of BCa patients with different clinical situations and may help to find a useful target for tumor therapy.

Bioinformatic Evidence Reveals that Cell Cycle Correlated Genes Drive the Communication between Tumor Cells and the Tumor Microenvironment and Impact the Outcomes of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is an aggressive cancer type with poor prognosis; thus, there is especially necessary and urgent to screen potential prognostic biomarkers for early diagnosis and novel therapeutic targets. In this study, we downloaded target data sets from the GEO database, and obtained codifferentially expressed genes using the limma R package and identified key genes through the protein–protein interaction network and molecular modules, and performed GO and KEGG pathway analyses for key genes via the clusterProfiler package and further determined their correlations with clinicopathological features using the Oncomine database. Survival analysis was completed in the GEPIA and the Kaplan–Meier plotter database. Finally, correlations between key genes, cell types infiltrated in the tumor microenvironment (TME), and hypoxic signatures were explored based on the TIMER database. From the results, 11 key genes related to the cell cycle were determined, and high levels of these key genes' expression were focused on advanced and higher grade status HCC patients, as well as in samples of TP53 mutation and vascular invasion. Besides, the 11 key genes were significantly associated with poor prognosis of HCC and also were positively related to the infiltration level of MDSCs in the TME and the HIF1A and VEGFA of hypoxic signatures, but a negative correlation was found with endothelial cells (ECs) and hematopoietic stem cells. The result determined that 11 key genes (RRM2, NDC80, ECT2, CCNB1, ASPM, CDK1, PRC1, KIF20A, DTL, TOP2A, and PBK) could play a vital role in the pathogenesis of HCC, drive the communication between tumor cells and the TME, and act as probably promising diagnostic, therapeutic, and prognostic biomarkers in HCC patients.

The role of hypoxia-induced long noncoding RNAs (lncRNAs) in tumorigenesis and metastasis

Long noncoding RNAs (lncRNAs) are noncoding RNAs with length greater than 200 nt. The biological roles and mechanisms mediated by lncRNAs have been extensively investigated. Hypoxia is a proven microenvironmental factor that promotes solid tumor metastasis. Epithelial-mesenchymal transition (EMT) is one of the major mechanisms induced by hypoxia to contribute to metastasis. Many lncRNAs have been shown to be induced by hypoxia and their roles have been delineated. In this review, we focus on the hypoxia-inducible lncRNAs that interact with protein/protein complex and chromatin/epigenetic factors, and the mechanisms that contribute to metastasis. The role of a recently discovered lncRNA RP11-390F4.3 in hypoxia-induced EMT is discussed. Whole genome approaches to delineating the association between lncRNAs and histone modifications are discussed. Other topics related to hypoxia-induced tumor progression but require further investigation are also mentioned. The clinical significance and treatment strategy targeted against lncRNAs are discussed. The review aims to identify suitable lncRNA targets that may provide feasible therapeutic venues for hypoxia-involved cancers.

An immune-related lncRNA signature for the prognosis of pancreatic adenocarcinoma

Recent evidence suggests that aberrant expression of long non-coding RNA (lncRNA) can drive the initiation and progression of malignancies. However, little is known about the prognostic potential of lncRNA. We aimed at constructing a lncRNA-based signature to improve the prognosis prediction of pancreatic adenocarcinoma (PAAD). The PAAD samples with clinical information were obtained from The Cancer Genome Atlas and International Cancer Genome Consortium. We established an eight-IRlncRNA signature in a training cohort. The prognostic value of eight-IRlncRNA signature was validated in two distinct cohorts when compared to other four prognostic models. We continued to analyze its independence in subgroups by univariate and multivariate Cox regression. We constructed a nomogram for clinicopathologic features and 1-, 3-, and 5-year overall survival performance. Moreover, Gene set enrichment analysis and Gene Set Variation Analysis distinguished the typical functions between high- and low-risk groups. In addition, we further observed the different correlations of immune cell between eight IRlncRNAs. Eight-IRlncRNA signature appears to be a good performer to predict the survival capability of PAAD patients, and the nomogram will enable PAAD patients to be more accurately managed in clinical practice.

The Hypoxia-Long Noncoding RNA Interaction in Solid Cancers

Hypoxia is one of the representative microenvironment features in cancer and is considered to be associated with the dismal prognosis of patients. Hypoxia-driven cellular pathways are largely regulated by hypoxia-inducible factors (HIFs) and notably exert influence on the hallmarks of cancer, such as stemness, angiogenesis, invasion, metastasis, and the resistance towards apoptotic cell death and therapeutic resistance; therefore, hypoxia has been considered as a potential hurdle for cancer therapy. Growing evidence has demonstrated that long noncoding RNAs (lncRNAs) are dysregulated in cancer and take part in gene regulatory networks owing to their various modes of action through interacting with proteins and microRNAs. In this review, we focus attention on the relationship between hypoxia/HIFs and lncRNAs, in company with the possibility of lncRNAs as candidate molecules for controlling cancer.

Hsa-miR-30a-3p attenuates gastric adenocarcinoma proliferation and metastasis via APBB2

Background: There is a well-established relationship between cell cycle progression and the development of stomach adenocarcinoma. This study aimed to elucidate the molecular mechanism and biological function of APBB2 in gastric cancer.

Methods: Gastric adenocarcinoma (GA) data were downloaded from the TCGA-GA and GEO databases and analyzed to explore differentially expressed miRNAs and mRNAs. Moreover, potential target mRNAs were also predicted. The relative level of gene and protein expression in GA cell lines and gastric mucosa cells was detected by q-PCR and Western blot, respectively. Moreover, the influence of APBB2 on proliferation, metastasis, and cell cycle changes in SGC-7901 and BGC-823 cells was evaluated. The binding relationship between the target miRNA and mRNA was confirmed with a dual-luciferase reporter assay.

Results: High APBB2 expression was detected in GA patients, indicating that it may be represent a predictive biomarker for poor prognosis. Related experiments confirmed that APBB2 silencing inhibited GA cellular functions, including proliferation, cell cycle progression, migration, and invasion. In addition, to explore the molecular mechanism, our results indicated that the binding sites were located at hsa-mir-30a and the 3′-UTR of APBB2, suggesting that hsa-mir-30a can regulate the expression of APBB2. The biological functions of hsa-mir-30a were also evaluated. Hsa-mir-30a overexpression attenuated the proliferation and metastasis of cancer cells. In rescue experiments, hsa-mir-30a was confirmed to reverse the cell cycle promoting function associated with APBB2 overexpression.

Conclusion: Our findings show that hsa-mir-30a can attenuate the development of GA by down-regulating APBB2 expression.

MTHFD2 promotes tumorigenesis and metastasis in lung adenocarcinoma by regulating AKT/GSK-3β/β-catenin signalling

Recent studies have demonstrated that one‐carbon metabolism plays a significant role in cancer development. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), a mitochondrial enzyme of one‐carbon metabolism, has been reported to be dysregulated in many cancers. However, the specific role and mechanism of MTHFD2 in lung adenocarcinoma (LUAD) still remains unclear. In this study, we evaluated the clinicopathological and prognostic values of MTHFD2 in LUAD patients. We conducted a series of functional experiments in vivo and in vitro to explore novel mechanism of MTHFD2 in LUAD. The results showed that MTHFD2 was significantly up‐regulated in LUAD tissues and predicted poor prognosis of LUAD patients. Knockdown of MTHFD2 dramatically inhibited cell proliferation and migration by blocking the cell cycle and inducing the epithelial‐mesenchymal transition (EMT). In addition, MTHFD2 knockdown suppressed LUAD growth and metastasis in cell‐derived xenografts. Mechanically, we found that MTHFD2 promoted LUAD cell growth and metastasis via AKT/GSK‐3β/β‐catenin signalling. Finally, we identified miR‐30a‐3p as a novel regulator of MTHFD2 in LUAD. Collectively, MTHFD2 plays an oncogenic role in LUAD progression and is a promising target for LUAD diagnosis and therapy.

CircHIPK3 regulates pulmonary fibrosis by facilitating glycolysis in miR-30a-3p/FOXK2-dependent manner

Pulmonary fibrosis develops when myofibroblasts and extracellular matrix excessively accumulate in the injured lung, but what drives fibrosis is not fully understood. Glycolysis has been linked to cell growth and proliferation, and several studies have shown enhanced glycolysis promotes pulmonary fibrosis. However, detailed studies describing this switch remain limited. Here, we identified that TGF-β1 effectively increased the expression of circHIPK3 in lung fibroblasts, and circHIPK3 inhibition attenuated the activation, proliferation, and glycolysis of fibroblasts in vitro. Dual-luciferase reporter gene assays, RNA immunoprecipitation (RIP), and RNA pull-down assays showed that circHIPK3 could function as a sponge of miR-30a-3p and inhibit its expression. Furthermore, FOXK2, a driver transcription factor of glycolysis, was identified to be a direct target of miR-30a-3p. Mechanistically, circHIPK3 could enhance the expression of FOXK2 via sponging miR-30a-3p, thereby facilitating fibroblast glycolysis and activation. Besides, miR-30a-3p overexpression or FOXK2 knockdown blocked fibroblast activation induced by TGF-β1 and abrogated the profibrotic effects of circHIPK3. Moreover, circHIPK3 and miR-30a-3p were also dysregulated in fibrotic murine lung tissues induced by silica. Adeno-associated virus (AAV)-mediated circHIPK3 silence or miR-30a-3p overexpression alleviated silica-induced pulmonary fibrosis in vivo. In conclusion, our results identified circHIPK3/miR-30a-3p/FOXK2 regulatory pathway as an important glycolysis cascade in pulmonary fibrosis.

LINC01436 Inhibited miR-585-3p Expression and Upregulated MAPK1 Expression to Promote Gastric Cancer Progression

BACKGROUND

Gastric cancer (GC) is a prevalent type of digestion system malignancies. Dysregulation of long non-coding RNAs (lncRNAs) has been proven to be prognostic factors and biological regulators in human cancers.

AIMS

The current study aimed to explore the role of long intergenic non-protein coding RNA 1436 (LINC01436) and its underlying mechanism in the progression of GC.

METHODS

RT-qPCR was conducted to measure RNA expression. Western blot was used for exploration of protein level. CCK-8, caspase-3 activity, and transwell assays were applied to evaluate the proliferative, apoptotic, and migratory abilities of GC cells, respectively. Mechanical experiments were used to probe the molecular interplay between genes.

RESULTS

High LINC01436 level suggested low overall survival in GC patients, and LINC01436 was highly expressed in GC tissues and cells. Besides, LINC01436 knockdown hampered cell proliferation and migration, while facilitated cell apoptosis. Mechanistically, LINC01436 upregulated mitogen-activated protein kinase 1 (MAPK1) expression by competitively binding with miR-585-3p and inhibiting miR-585-3p expression. Furthermore, LINC01436 negatively regulated miR-585-3p expression by enhancing the zeste 2 polycomb repressive complex 2 subunit (EZH2)-induced trimethylation of histone H3 at lysine 27 (H3K27me3) on miR-585-3p promoter. Final rescue assays revealed that overexpression of MAPK1 could rescue the suppressive influence of LINC01436 depletion on GC progression.

CONCLUSIONS

LINC01436 epigenetically silences miR-585-3p and acts as miR-585-3p to upregulate MAPK1 expression and promote GC progression.

MicroRNA-30a-3p acts as a tumor suppressor in MHCC-97H hepatocellular carcinoma cells by targeting COX-2

MicroRNAs (miRNAs) are small, noncoding RNAs which can bind to target mRNAs and regulate gene expression. Increasing evidences suggest that miRNAs play an important role in driving hepatocellular carcinoma (HCC) progression by regulating tumor cell proliferation, apoptosis, invasion, and migration. In this study, we demonstrated that the expression of microRNA-30a-3p (miR-30a-3p) was reduced in HCC cell lines in comparison to immortalized liver cell line, LO2. Augmented miR-30a-3p level markedly inhibited MHCC-97H cell growth, migration and invasion in vitro. MiR-30a-3p was also found to inhibit tumor growth in vivo using tumor-bearing mice. Mechanismly, COX-2 was discovered to be a direct and functional target of miR-30a-3p in MHCC-97H cells. Raised miR-30a-3p expression reduced the transcriptional level of COX-2 in MHCC-97H cells, while genetically upregulated COX-2 expression was able to reverse the function of miR-30a-3p-mediated suppression of MHCC-97H cells growth, migration and invasion. In addition, we found that using a COX-2 inhibitor, celecoxib, could enhance the anti-metastatic role of miR-30a-3p in MHCC-97H cells. Lastly, we found that decreased COX-2 protein level affected PGE2 production, leading to lower Bcl-2, Caspase-3, MMP2 and MMP9 expression but higher Bax and E-cadherin expression, which in turn culminated in higher rates of cell death and lower rates of cell migration. Taken together, our findings demonstrate that miR-30a-3p could be a target for the treatment of hepatocellular carcinoma cells progression.

Single-nucleotide polymorphism rs4142441 and MYC co-modulated long non-coding RNA OSER1-AS1 suppresses non-small cell lung cancer by sequestering ELAVL1

Single‐nucleotide polymorphisms (SNP) and long non‐coding RNAs (lncRNAs) have been involved in the process of lung cancer. Following clues given by lung cancer risk‐associated SNP, we aimed to find novel functional lncRNAs as candidate targets in lung cancer. We identified a lncRNA Oxidative Stress Responsive Serine Rich 1 Antisense RNA 1 (OSER1‐AS1) through a lung cancer risk‐associated SNP rs4142441. OSER1‐AS1 was down‐regulated in tumor tissue and its low expression was significantly associated with poor overall survival among non‐smokers in non‐small cell lung cancer (NSCLC) patients. Gain‐ and loss‐of‐function studies showed that OSER1‐AS1 acted as a tumor suppressor by inhibiting lung cancer cell growth, migration and invasion in vitro. Xenograft tumor assays and a metastasis mouse model confirmed that OSER1‐AS1 suppressed tumor growth and metastasis in vivo. The promoter of OSER1‐AS1 was repressed by MYC, and the 3′‐end of OSER1‐AS1 was competitively targeted by microRNA hsa‐miR‐17‐5p and RNA‐binding protein ELAVL1. Our results indicated that OSER1‐AS1 exerted tumor‐suppressive functions by acting as an ELAVL1 decoy to keep it away from its target mRNAs. Our findings characterized OSER1‐AS1 as a new tumor‐suppressive lncRNA in NSCLC, suggesting that OSER1‐AS1 may be suitable as a potential biomarker for prognosis, and a potential target for treatment.

EPAS1 promotes peritoneal carcinomatosis of non-small-cell lung cancer by enhancing mesothelial-mesenchymal transition

BACKGROUND

Non-small-cell lung cancer (NSCLC) is a major cause of cancer-related death globally. Endothelial PAS domain-containing protein 1 (EPAS1) is a homolog of the hypoxia-inducible factor 1α and has been reported to confer tyrosine kinase inhibitor (TKI) resistance in NSCLC, but its role in peritoneal carcinomatosis of NSCLC is unknown.

METHODS

PC14HM, a high metastatic potential subline of NSCLC cell line PC14, was derived. Stable shRNA knockdown of EPAS1 was then established in PC14HM cells and subjected to assessment regarding the effects on proliferation and viability, xenograft tumor growth, metastatic potential, mesothelial-mesenchymal transition (MMT)-related characteristics and peritoneal carcinomatosis in a mouse model.

RESULTS

EPAS1 expression was elevated in PC14HM cells. Knockdown of EPAS1 inhibited the proliferation and viability of PC14HM cells in vitro and suppressed tumorigenesis in vivo. In addition, the metastatic features and in vitro productions of MMT-inducing factors in PC14HM cells was also associated with EPAS1. More importantly, knockdown of EPAS1 drastically suppressed peritoneal carcinomatosis of PC14HM cells in vivo.

CONCLUSION

EPAS1 promotes peritoneal carcinomatosis of NSCLC through enhancement of MMT and could therefore serve as a prognostic marker or a therapeutic target in treating NSCLC, particularly in patients with peritoneal carcinomatosis.

CircRNA-23525 regulates osteogenic differentiation of adipose-derived mesenchymal stem cells via miR-30a-3p

Adipose-derived mesenchymal stem cells (ADSCs) are considered to be seed cells in bone tissue engineering and emerging evidence indicates that circular RNAs (circRNAs) function in the osteogenic differentiation of ADSCs. The mechanisms of osteoblastic differentiation of ADSCs from the perspective of circRNA modulation are examined in this study. First, circRNA-23525 was upregulated during osteoblastic differentiation of ADSCs. Second, overexpression of circRNA-23525 increased Runx2, ALP and OCN at both mRNA and protein levels. Alkaline phosphatase (ALP) and Alizarin Red staining indicated a similar tendency. Silencing circRNA-23525 produced the opposite effect. Bioinformatics analysis with luciferase assays confirmed that circRNA-23525 functioned as a sponge for miR-30a-3p. In the osteoblastic differentiation of ADSCs, the dynamic expression of miR-30a-3p and circRNA-23525 resulted in an opposite trend at 3, 7 and 14 days. Overexpression of circRNA-23525 downregulated miR-30a-3p and knockdown of circRNA-23525 promoted the expression of miR-30a-3p. Bioinformatics methods and luciferase assays suggested that miR-30a-3p modulated Runx2 expression by targeting 3'UTR. Knockdown of miR-30a-3p facilitated osteogenesis in ADSCs and enhancing miR-30a-3p interfered with the osteogenic process. Finally, circRNA-23525 overexpression significantly increased Runx2 expression, while co-transfection of miR-30a-3p mimics reversed it. Runx2 expression was decreased in circRNA-23525-knockdown ADSCs but expression was rescued by including the miR-30a-3p inhibitor in the osteoblastic process. ALP activity and mineralized bone matrix confirmed the function of circRNA-23525/miR-30a-3p in osteogenesis. Taken together, the current study demonstrated that circRNA-23525 regulates Runx2 expression via targeting miR-30a-3p and is thus a positive regulator in the osteoblastic differentiation of ADSCs.

Lnc-GAN1 expression is associated with good survival and suppresses tumor progression by sponging mir-26a-5p to activate PTEN signaling in non-small cell lung cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) play vital roles in the development and progression of non-small-cell lung cancer (NSCLC); however, the role of most lncRNAs in NSCLC remains unknown. This study explored the clinical significance, biological function and underlying mechanism of lnc-GAN1 in NSCLC.

METHODS

With a custom lncRNA microarray we found that lnc-GAN1 is markedly downregulated in NSCLC tissues. Then lnc-GAN1 expression level was measured using qRT-PCR in NSCLC tissues and cell lines. Survival was assessed using the Kaplan-Meier method. The biological functions of lnc-GAN1 in lung cancer cells were evaluated in vitro and in vivo. RNA fluorescence in situ hybridization and subcellular localization assays revealed the subcellular distribution of lnc-GAN1 in cells. Bioinformatic analysis was adopted to predict miRNAs and signaling pathways regulated by lnc-GAN1. RNA immunoprecipitation and Dual-luciferase reporter assays were used to assess the interaction between lnc-GAN1 and miR-26a-5p in lung cancer cells.

RESULTS

lnc-GAN1 is downregulated in HCC tissues and associated with larger tumor size and poor overall survival and disease-free survival; its ectopic expression suppresses cell proliferation, colony formation, and cell cycle progression and induces apoptosis in NSCLC cells; it also inhibits tumor growth in the NSCLC xenograft model. We further proved that lnc-GAN1 is localized in cytoplasm and transcribed independently from its parental gene GAN. Mechanistically, lnc-GAN1 acts as a sponge for miR-26a-5p by two seed sequences, and the two non-coding RNAs have a negative relationship in NSCLC tissues; we further prove that PTEN is a direct target of miR-26a-5p and lnc-GAN1 inhibits cell cycle signaling pathway by activating PTEN, whose expression level correlated negatively with miR-26a-5p level but positively with lnc-GAN1 level in NSCLC samples.

CONCLUSIONS

Lnc-GAN1 is downregulated and associated with poor survival of NSCLC patients, and mechanistically acts as a tumor suppressor via sponging and inhibiting miR-26a-5p to upregulate PTEN. This study provides a potential prognostic biomarker and treatment target for NSCLC.

MiR-30a-5p ameliorates LPS-induced inflammatory injury in human A549 cells and mice via targeting RUNX2

In this study, we aim to investigate the role of miR-30a-5p in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) using LPS-induced A549 cells and mice. We found cell viability was significantly declined accompanied by cell apoptosis and cell cycle arrest at G0/G1 phase in LPS-treated A549 cells. MiR-30a-5p was down-regulated by LPS treatment and miR-30a-5p significantly protected A549 cells from LPS-induced injury by increasing cell viability, reducing cell apoptosis, promoting cell cycle progression, and inhibiting inflammatory reactions. Dual-luciferase activity demonstrated that RUNX2 was a direct target for miR-30a-5p and its expression was negatively and directly regulated by miR-30a-5p. Over-expression of RUNX2 weakened the inhibitory effect of miR-30a-5p on inflammatory injury. In vivo, over-expression of miR-30a-5p alleviated LPS-induced inflammatory responses and lung injury in LPS-administrated mice. Besides, miR-30a-5p repressed LPS-elevated phosphorylation levels of the signal transducer and activator of transcription 3 (STAT3) and c-Jun N-terminal kinase (JNK), IκBα degradation, and NF-κB p65 phosphorylation. In conclusion, miR-30a-5p ameliorates LPS-induced inflammatory injury in A549 cells and mice via targeting RUNX2 and related signaling pathways, thereby influencing the progression of ARDS.

Long Noncoding RNA PTPRG Antisense RNA 1 Reduces Radiosensitivity of Nonsmall Cell Lung Cancer Cells Via Regulating MiR-200c-3p/TCF4

Background:

PTPRG antisense RNA 1 has been well-documented to exert an oncogenic role in diverse neoplasms. However, the precise role of PTPRG antisense RNA 1 in regulating radiosensitivity of nonsmall cell lung cancer cells remains largely elusive.

Methods:

Expression levels of PTPRG antisense RNA 1 and miR-200c-3p in nonsmall cell lung cancer tissues and cells were detected by quantitative real-time polymerase chain reaction, while transcription factor 4 expression was examined by immunohistochemistry and Western blot. After nonsmall cell lung cancer cells were exposed to X-ray with different doses in vitro, Cell Counting Kit-8 assay and colony formation assay were conducted to determine the influence of PTPRG antisense RNA 1 on cell viability. Interaction between miR-200c-3p and PTPRG antisense RNA 1 as well as transcription factor 4 was investigated by dual luciferase reporter assay.

Result:

In nonsmall cell lung cancer tissues, the expressions of PTPRG antisense RNA 1 and transcription factor 4 were significantly upregulated, whereas the expression of miR-200c-3p was downregulated. It was also proved that PTPRG antisense RNA 1 and 3′-untranslated region of transcription factor 4 can bind to miR-200c-3p. Under X-ray irradiation, overexpressed PTPRG antisense RNA 1 could promote the viability and enhance the radioresistance of nonsmall cell lung cancer cells, and this effect was partially weakened by miR-200c-3p mimics. Transcription factor 4 was identified as a target gene of miR-200c-3p, which could be positively regulated by PTPRG antisense RNA 1.

Conclusion:

PTPRG antisense RNA 1 reduces the radiosensitivity of nonsmall cell lung cancer cells via modulating miR-200c-3p/TCF4 axis.

LINC01436 Promotes the Progression of Gastric Cancer via Regulating miR-513a-5p/APE1 Axis

Background

Gastric cancer (GC) is one of the deadliest cancer worldwide. Multiple long non-coding RNAs (lncRNAs) are recently identified as crucial oncogenic factors or tumor suppressors in GC. In this study, we aimed to probe into the effect of LINC01436 on GC progression.

Methods

LINC01436 and miR-513a-5p expressions in GC tissue samples were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used to detect the expression of apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) expression. Human GC cell lines AGS and BGC-823 were employed to investigate the function and mechanism of LINC01436 in GC. Cell counting kit-8 (CCK-8) assay was used to assess the effect of LINC01436 on proliferation. Flow cytometry was utilized to explore the effect of LINC01436 on apoptosis, and Transwell assay was conducted to detect the effect of LINC01436 on the migration and invasion. Colony formation assay was performed to evaluate the effect of LINC01436 on radioresistance of GC cells. Furthermore, luciferase reporter assay and RNA immunoprecipitation assay were conducted to confirm the binding relationship between miR-513a-5p and LINC01436. Additionally, Western blot was used to study the regulatory function of LINC01436 and miR-513a-5p on APE1.

Results

LINC01436 expression of GC clinical samples was remarkably increased and LINC01436 was correlated with unfavorable pathological indexes. LINC01436 high expression was associated with shorter overall survival time. Its overexpression observably promoted the proliferation, metastasis and radioresistance of GC cells, and its knockdown suppressed the malignant phenotypes of GC cells. LINC01436 overexpression markedly reduced the miR-513a-5p expression via sponging it and enhanced the APE1 expression. MiR-513a-5p overexpression or APE1 knockdown reversed the effects of LINC01436 on GC cells.

Conclusion

LINC01436 is a molecular sponge of tumor suppressor miR-513a-5p, which indirectly enhances the APE1 expression and functions as the oncogenic lncRNA in GC.

Role of miR-30a-3p Regulation of Oncogenic Targets in Pancreatic Ductal Adenocarcinoma Pathogenesis

Our recent studies have implicated some passenger strands of miRNAs in the molecular pathogenesis of human cancers. Analysis of the microRNA (miRNA) expression signature in pancreatic ductal adenocarcinoma (PDAC) has shown that levels of miR-30a-3p, the passenger strand derived from pre-mir-30a, are significantly downregulated in PDAC tissues. This study aimed to identify the oncogenes closely involved in PDAC molecular pathogenesis under the regulation of miR-30a-3p. Ectopic expression assays showed that miR-30a-3p expression inhibited the aggressiveness of the PDAC cells, suggesting that miR-30a-3p acts as a tumor-suppressive miRNA in PDAC cells. We further identified 102 putative targets of miR-30a-3p regulation in PDAC cells by combining in silico analysis with gene expression data. Of these, ten genes (EPS8, HMGA2, ENDOD1, SLC39A10, TGM2, MGLL, SERPINE1, ITGA2, DTL, and UACA) were independent prognostic factors in multivariate analysis of survival of patients with PDAC (p < 0.01). We also investigated the oncogenic function of the integrin ITGA2 in PDAC cell lines. The integrin family comprises cell adhesion molecules expressed as heterodimeric, transmembrane proteins on the surface of various cells. Overexpression of ITGA2/ITGB1 (an ITGA2 binding partner) was detected in the PDAC clinical specimens. The knockdown of ITGA2 expression attenuated the malignant phenotypes of the PDAC cells. Together, results from these microRNA-based approaches can accelerate our understanding of PDAC molecular pathogenesis.

LINC00173.v1 promotes angiogenesis and progression of lung squamous cell carcinoma by sponging miR-511-5p to regulate VEGFA expression

Background

Anti-angiogenic therapy represents a promising strategy for non-small-cell lung cancer (NSCLC) but its application in lung squamous cell carcinoma (SQC) is limited due to the high-risk adverse effects. Accumulating evidence indicates that long noncoding RNAs (lncRNAs) mediate in tumor progression by participating in the regulation of VEGF in NSCLC, which might guide the development of new antiangiogenic strategies.

Methods

Differential lncRNA expression in SQC was analyzed in AE-meta and TCGA datasets, and further confirmed in lung cancer tissues and adjacent normal tissues with RT-qPCR and in-situ hybridization. Statistical analysis was performed to evaluate the clinical correlation between LINC00173.v1 expression and survival characteristics. A tube formation assay, chick embryo chorioallantoic membrane assay and animal experiments were conducted to detect the effect of LINC00173.v1 on the proliferation and migration of vascular endothelial cells and tumorigenesis of SQC in vivo. Bioinformatics analysis, RNA immunoprecipitation and luciferase reporter assays were performed to elucidate the downstream target of LINC00173.v1. The therapeutic efficacy of antisense oligonucleotide (ASO) against LINC00173.v1 was further investigated in vivo. Chromatin immunoprecipitation and high throughput data processing and visualization were performed to identify the cause of LINC00173.v1 overexpression in SQC.

Results

LINC00173.v1 was specifically upregulated in SQC tissues, which predicted poorer overall and progression-free survival in SQC patients. Overexpression of LINC00173.v1 promoted, while silencing LINC00173.v1 inhibited the proliferation and migration of vascular endothelial cells and the tumorigenesis of SQC cells in vitro and in vivo. Our results further revealed that LINC00173.v1 promoted the proliferation and migration of vascular endothelial cells and the tumorigenesis of SQC cells by upregulating VEGFA expression by sponging miR-511-5p. Importantly, inhibition of LINC00173.v1 via the ASO strategy reduced the tumor growth of SQC cells, and enhanced the therapeutic sensitivity of SQC cells to cisplatin in vivo. Moreover, our results showed that squamous cell carcinoma-specific factor ΔNp63α contributed to LINC00173.v1 overexpression in SQC.

Conclusion

Our findings clarify the underlying mechanism by which LINC00173.v1 promotes the proliferation and migration of vascular endothelial cells and the tumorigenesis of SQC, demonstrating that LINC00173.v1-targeted drug in combination with cisplatin may serve as a rational regimen against SQC.

A circular RNA derived from DAB1 promotes cell proliferation and osteogenic differentiation of BMSCs via RBPJ/DAB1 axis

Osteogenesis (OS) is a type of differentiation that is of great importance for bone homeostasis. Increasing studies suggest circular RNAs (circRNAs) as pivotal regulators in OS. This study proposed to investigate mechanism mediated by circRNAs in OS. Based on GEO data and qRT-PCR assay, we found that circ-DAB1 (has_circ_0113689) was significantly up-regulated during osteogenic differentiation in human BMSCs. Overexpressing circ-DAB1 proliferation and osteogenic differentiation of BMSCs, whereas silencing circ-DAB1 elicited opposite functions. Subsequently, recombination signal-binding protein for immunoglobulin kappa J region (RBPJ), an important transcription factor in NOTCH pathway, was found to interact with DAB1 promoter while not to combine with circ-DAB1. Interestingly, circ-DAB1 overexpression could result in the increasing binding between RBPJ and DAB adaptor protein 1 (DAB1) promoter. Overexpressing circ-DAB1 upregulated RBPJ in BMSCs to induce DAB1 level. Further, we uncovered that circ-DAB1 upregulated RBPJ through sequestering miR-1270 and miR-944. Restoration experiments demonstrated that knocking down either RBPJ or DAB1 partially recovered BMSC proliferation and osteogenic differentiation that was suppressed by circ-DAB1 overexpression. Conclusively, circ-DAB1 promotes cell proliferation and osteogenic differentiation of BMSCs via NOTCH/RBPJ pathway.

Signaling in and out: long-noncoding RNAs in tumor hypoxia

Over the past few years, long non-coding RNAs (lncRNAs) are recognized as key regulators of gene expression at chromatin, transcriptional and posttranscriptional level with pivotal roles in various biological and pathological processes, including cancer. Hypoxia, a common feature of the tumor microenvironment, profoundly affects gene expression and is tightly associated with cancer progression. Upon tumor hypoxia, the central regulator HIF (hypoxia-inducible factor) is upregulated and orchestrates transcription reprogramming, contributing to aggressive phenotypes in numerous cancers. Not surprisingly, lncRNAs are also transcriptional targets of HIF and serve as effectors of hypoxia response. Indeed, the number of hypoxia-associated lncRNAs (HALs) identified has risen sharply, illustrating the expanding roles of lncRNAs in hypoxia signaling cascade and responses. Moreover, through extra-cellular vesicles, lncRNAs could transmit hypoxia responses between cancer cells and the associated microenvironment. Notably, the aberrantly expressed cellular or exosomal HALs can serve as potential prognostic markers and therapeutic targets. In this review, we provide an update of the current knowledge about the expression, involvement and potential clinical impact of lncRNAs in tumor hypoxia, with special focus on their unique molecular regulation of HIF cascade and hypoxia-induced malignant progression.

E2F6-Mediated Downregulation of MIR22HG Facilitates the Progression of Laryngocarcinoma by Targeting the miR-5000-3p/FBXW7 Axis

Recently, abundant evidence has clarified that long noncoding RNAs (lncRNAs) play an oncogenic or anticancer role in the tumorigenesis and development of diverse human cancers. Described as a crucial regulator in some cancers, MIR22HG has not yet been studied in laryngocarcinoma and therefore the underlying regulatory role of MIR22HG in laryngocarcinoma is worth detecting. In this study, MIR22HG expression in laryngocarcinoma cells was confirmed to be downregulated, and upregulated MIR22HG expression led to suppressive effects on laryngocarcinoma cell proliferation and migration. Molecular mechanism assays revealed that MIR22HG sponges miR-5000-3p in laryngocarcinoma cells. Besides, decreased expression of miR-5000-3p suppressed laryngocarcinoma cell proliferation and migration. Moreover, the FBXW7 gene was reported to be a downstream target gene of miR-5000-3p in laryngocarcinoma cells. More importantly, rescue assays verified that FBXW7 depletion or miR-5000-3p upregulation countervailed the repressive effects of MIR22HG overexpression on laryngocarcinoma progression. In addition, E2F6 was proved to be capable of inhibiting MIR22HG transcription in laryngocarcinoma cells. To sum up, E2F6-induced downregulation of MIR22HG promotes laryngocarcinoma progression through the miR-5000-3p/FBXW7 axis.

RNA methyltransferase NSUN2 promotes gastric cancer cell proliferation by repressing p57Kip2 by an m5C-dependent manner

The RNA methyltransferase NSUN2 has been involved in the cell proliferation and senescence, and is upregulated in various types of cancers. However, the role and potential mechanism of NSUN2 in gastric cancer remains to be determined. Our study showed that NSUN2 was significantly upregulated in gastric cancers, compared to adjacent normal gastric tissues. Moreover, NSUN2 could promote gastric cancer cell proliferation both in vitro and in vivo. Further study demonstrated that CDKN1C (p57^Kip2) was the potential downstream gene of regulated by NSUN2 in gastric cancer. NSUN2 could promote gastric cancer cell proliferation through repressing p57^Kip2 in an m⁵C-dependent manner. Our findings suggested that NSUN2 acted as an oncogene through promoting gastric cancer development by repressing p57^Kip2 in an m⁵C-dependent manner, which may provide a novel therapeutic target against gastric cancer.

Long non-coding RNAs: How to regulate the metastasis of non-small-cell lung cancer

Non–small‐cell lung cancer (NSCLC) has become the most lethal human cancer because of the high rate of metastasis. Hence, clarifying the molecular mechanism underlying NSCLC metastasis is very important to improve the prognosis of patients with NSCLC. Long non‐coding RNAs (LncRNAs) are a class of RNA molecules longer than 200 nucleotides, which can participate in diverse biological processes. About 18% of human LncRNAs were recently found to be associated with tumours. Many studies indicated that aberrant expression of LncRNAs played key roles in the progression and metastasis of NSCLC. According to the function in tumours, LncRNAs can be divided into two classes: oncogenic LncRNAs and tumour‐suppressor LncRNAs. In this review, we summarized the main molecular mechanism of LncRNAs regulating NSCLC metastasis, including three aspects: (a) LncRNAs interact with miRNAs as ceRNAs; (b) LncRNAs bind with target proteins; and (c) LncRNAs participate in the transduction of different signal pathways. Then, LncRNAs can exert their function to regulate the metastasis of NSCLC through influencing the progression of epithelial‐mesenchymal transition (EMT) and the properties of cancer stem cell (CSC). But, it is necessary to do some further research to demonstrate the LncRNAs particular regulatory mechanism of inhibiting the metastasis of NSCLC and explore new drugs targeting LncRNAs.

LINC01436, regulating miR-585 and FBXO11, is an oncogenic lncRNA in the progression of gastric cancer

Accumulating studies have indicated that long non-coding RNAs (lncRNAs) are crucial modulators in cancer biology. In this work, we investigated the function and related mechanisms of LINC01436 in the progression of gastric cancer (GC). We demonstrated that LINC01436 was significantly up-regulated in cancerous tissues of GC samples, and its overexpression was correlated with a worse prognosis for the patients. In the GC cell line BGC823 cells, LINC01436 knockdown repressed the proliferation and metastasis of cancer cells; conversely, in GC cell line AGS cells, overexpression of LINC01436 showed the opposite effects. We then demonstrated that miR-585, a tumor suppressor, could bind to both LINC01436 and the 3'-UTR of F-box protein 11 (FBOX11), and LINC01436 was proved to sponge miR-585 and repress it, and indirectly promoted the expression of FBOX11. Collectively, these results suggested that LINC01436 was an oncogenic lncRNA in GC and promoted proliferation and metastasis of GC cell via regulating miR-585 and FBOX11.

Current Landscape of Epigenetics in Lung Cancer: Focus on the Mechanism and Application

Lung cancer is the leading cause of cancer-related mortality worldwide. Tumorigenesis involves a multistep process resulting from the interactions of genetic, epigenetic, and environmental factors. Genome-wide association studies and sequencing studies have identified many epigenetic alterations associated with the development of lung cancer. Epigenetic mechanisms, mainly including DNA methylation, histone modification, and noncoding RNAs (ncRNAs), are heritable and reversible modifications that are involved in some important biological processes and affect cancer hallmarks. We summarize the major epigenetic modifications in lung cancer, focusing on DNA methylation and ncRNAs, their roles in tumorigenesis, and their effects on key signaling pathways. In addition, we describe the clinical application of epigenetic biomarkers in the early diagnosis, prognosis prediction, and oncotherapy of lung cancer. Understanding the epigenetic regulation mechanism of lung cancer can provide a new explanation for tumorigenesis and a new target for the precise treatment of lung cancer.

A novel 3'-tRNAGlu-derived fragment acts as a tumor suppressor in breast cancer by targeting nucleolin

tRNA-derived fragments (tRFs) have been defined as a novel class of small noncoding RNAs. tRFs have been reported to be deregulated in cancer, but their biologic function remains to be fully understood. We have identified a new tRF (named tRF3E), derived from mature tRNAGlu, that is specifically expressed in healthy mammary glands but not in breast cancer (BC). Consistently, tRF3E levels significantly decrease in the blood of patients with epidermal growth factor receptor 2 (HER2)-positive BC reflecting tumor status (control > early cancer > metastatic cancer). tRF3E down-regulation was recapitulated in Δ16HER2 transgenic mice, representing a BC preclinical model. Pulldown assays, used to search for proteins capable to selectively bind tRF3E, have shown that this tRF specifically interacts with nucleolin (NCL), an RNA-binding protein overexpressed in BC and able to repress the translation of p53 mRNA. The binding properties of NCL-tRF3E complex, predicted in silico and analyzed by EMSA assays, are congruent with a competitive displacement of p53 mRNA by tRF3E, leading to an increased p53 expression and consequently to a modulation of cancer cell growth. Here, we provide evidence that tRF3E plays an important role in the pathogenesis of BC displaying tumor-suppressor functions through a NCL-mediated mechanism.-Falconi, M., Giangrossi, M., Elexpuru Zabaleta, M., Wang, J., Gambini, V., Tilio, M., Bencardino, D., Occhipinti, S., Belletti, B., Laudadio, E., Galeazzi, R., Marchini, C., Amici, A. A novel 3'-tRNAGlu-derived fragment acts as a tumor suppressor in breast cancer by targeting nucleolin.

A Genomic-Clinicopathologic Nomogram Predicts Survival for Patients with Laryngeal Squamous Cell Carcinoma

Background

Long noncoding RNAs (lncRNAs), which have little or no ability to encode proteins, have attracted special attention due to their potential role in cancer disease. We aimed to establish a lncRNA signature and a nomogram incorporating the genomic and clinicopathologic factors to improve the accuracy of survival prediction for laryngeal squamous cell carcinoma (LSCC).

Methods

A LSCC RNA-sequencing (RNA-seq) dataset and the matched clinicopathologic information were downloaded from The Cancer Genome Atlas (TCGA). Using univariable Cox regression and least absolute shrinkage and selection operator (LASSO) analysis, we developed a thirteen-lncRNA signature related to prognosis. On the basis of multivariable Cox regression analysis results, a nomogram integrating the genomic and clinicopathologic predictors was built. The predictive accuracy and discriminative ability of the inclusive nomogram were confirmed by calibration curve and a concordance index (C-index), and compared with the TNM staging system by C-index and receiver operating characteristic (ROC) analysis. Decision curve analysis (DCA) was conducted to evaluate the clinical value of our nomogram.

Results

Thirteen overall survival- (OS-) related lncRNAs were identified, and the signature consisting of the selected thirteen lncRNAs could effectively divide patients into high-risk and low-risk subgroups, with area under curves (AUC) of 0.89 (3-year OS) and 0.885 (5-year OS). Independent factors derived from multivariable analysis to predict survival were margin status, tumor status, and lncRNA signature, which were all assembled into the nomogram. The calibration curve for the survival probability showed that the predictions based on the nomogram coincided well with actual observations. The C-index of the nomogram was 0.82 (0.77-0.87), and the area under curve (AUC) of the nomogram in predicting overall survival (OS) was 0.938, both of which were significantly higher than the traditional TNM stage. Decision curve analysis further demonstrated that our nomogram had larger net benefit than TNM stage.

Conclusion

An inclusive nomogram for patients with LSCC, comprising genomic and clinicopathologic variables, generates more accurate estimations of the survival probability when compared with TNM stage alone, but more data are needed before the nomogram is used in clinical practice.

Xiaoai Jiedu Recipe Inhibits Proliferation and Metastasis of Non-Small Cell Lung Cancer Cells by Blocking the P38 Mitogen-Activated Protein Kinase (MAPK) Pathway

BACKGROUND Lung cancer is the leading cause of cancer deaths in the world. Its major histopathological subtype is non-small cell lung cancer (NSCLC). Xiaoai Jiedu recipe (XJR) is a traditional Chinese medicine formula that can suppress growth and invasion of tumor cells. Here, we assessed the antitumor effect of XJR on NSCLC explored the underlying mechanisms. MATERIAL AND METHODS Three concentrations of XJR (low, middle, and high) were used to treat A549 cells. Cell Counting Kit-8 and colony formation assay were used to measure proliferation of A549 cells. Apoptosis was evaluated by Hoechst 33342 staining and flow cytometry. The expression of apoptosis-associated proteins was measured by Western blot analysis. Transwell and scratch wound healing assay were used to assess invasion and migration, respectively, of A549 cells. The expression of p38 MAPK pathway-associated proteins were measured using Western blot analysis. RESULTS XJR suppressed proliferation and promoted apoptosis of A549 cells, especially in the high-dose group. The expression of Bcl-2 was reduced with increasing expression of Bax, cleaved caspase-3, and cleaved caspase-9. Invasion and migration abilities of A549 cells were inhibited after XJR treatment. XJR treatment decreased the expression levels of phosphorylated p38 (p-p38), p-ERK, and p-JNK in a dose-dependent manner. CONCLUSIONS The results demonstrated that XJR can inhibit proliferation, invasion, and migration, and induce apoptosis of NSCLC by blocking the p38 MAPK pathway, which shows the potential of XJR as a new treatment of NSCLC.

E2F6-mediated lncRNA CASC2 down-regulation predicts poor prognosis and promotes progression in gastric carcinoma

AIMS

To investigate the potential biological role of E2F6 and its underlying molecular mechanism in gastric carcinoma (GC) progression.

MAIN METHODS

The expressions of cancer susceptibility candidate 2 (CASC2), E2F6 and matrix metalloprotein-2 (MMP-2) were measured by quantitative real-time polymerase chain reaction and western blotting. The inhibitory effect of E2F6 on CASC2 was evaluated using luciferase reporter assay. Cell growth was assessed by colony formation assay and cell counting kit-8. Cell invasion and apoptosis were measured by transwell assay and flow cytometry assay, respectively. In vivo tumorigenicity was assessed by tumor xenografts in nude mice.

KEY FINDINGS

Our data revealed that CASC2 was downregulated while E2F6 was upregulated in GC tissues and cell lines. Remarkably, lower expression of CASC2 was associated with poor survival in GC patients. E2F6 inhibited the expression of CASC2. Subsequently, reliable data showed that downregulation of E2F6 suppressed the proliferation and invasion, and promoted the apoptosis of GC cells. Furthermore, downregulation of E2F6 decreased the expression of MMP-2 and increased the activity of caspase-3. However, these changes triggered by E2F6 knockdown could be reversed by inhibition of CASC2. Moreover, we also proved that downregulation of CASC2 reverses the effect of E2F6 knockdown on tumor growth in vivo.

SIGNIFICANCE

Our data demonstrated that E2F6 could regulate the proliferation, invasion and apoptosis of GC cells via inhibiting the expression of CASC2, suggesting that E2F6/CASC2 axis is another regulator of GC progression.

Long noncoding RNA HOXA-AS2 promotes non-small cell lung cancer progression by regulating miR-520a-3p

Background: The HOXA cluster antisense RNA 2 (HOXA-AS2) has recently been discovered to be involved in carcinogenesis in multiple cancers. However, the role and underlying mechanism of HOXA-AS2 in non-small cell lung cancer (NSCLC) yet need to be unraveled. Methods: HOXA-AS2 expression in NSCLC tissues and cell lines was detected using quantitative real-time PCR (qRT-PCR). Furthermore, the effects of HOXA-AS2 on NSCLC cell proliferation, apoptosis, migration, and invasion were assessed by MTS, flow cytometry, wound healing and transwell invasion assays, respectively. Starbase2.0 predicted and luciferase reporter and RNA immunoprecipitation (RIP) assays were used to validate the association of HOXA-AS2 and miR-520a-3p in NSCLC cells. Results: Our results revealed that HOXA-AS2 in NSCLC tissues were up-regulated and cell lines, and were associated with poor prognosis and overall survival. Further functional assays demonstrated that HOXA-AS2 knockdown significantly inhibited NSCLC cell proliferation, induced cell apoptosis and suppressed migration and invasion. Starbase2.0 predicted that HOXA-AS2 sponge miR-520a-3p at 3'-UTR, which was confirmed using luciferase reporter and RIP assays. miR-520a-3p expression was inversely correlated with HOXA-AS2 expression in NSCLC tissues. In addition, miR-520a-3p inhibitor attenuated the inhibitory effect of HOXD-AS2-depletion on cell proliferation, migration and invasion of NSCLC cells. Moreover, HOXA-AS2 could regulate HOXD8 and MAP3K2 expression, two known targets of miR-520a-3p in NSCLC. Conclusion: These findings implied that HOXA-AS2 promoted NSCLC progression by regulating miR-520a-3p, suggesting that HOXA-AS2 could serve as a therapeutic target for NSCLC.