Enhanced expression of long non-coding RNA ZXF1 promoted the invasion and metastasis in lung adenocarcinoma

New link between RNH1 and E2F1: regulates the development of lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is a non-small cell carcinoma. Ribonuclease/angiogenin inhibitor 1 (RNH1) exerts multiple roles in virous cancers. E2F1 is a critical transcription factor involved in the LUAD development. Here, we analyze the expression of RNH1 in LUAD patients, investigate the biological function of RNH1 in LUAD, and demonstrate its potential mechanisms through E2F1 in LUAD.

METHODS

In the present study, we presented the expression of RNH1 in LUAD based on the database and confirmed it by western blot detection of RNH1 in human LUAD tissues. Lentiviral infection was constructed to silence or overexpress RNH1 in NCI-H1395 and NCI-H1437 cells. We assess the role of RNH1 on proliferation in LUAD cells by MTT assay, colony formation assays, and cell cycle detection. Hoechst staining and flow cytometry were used to evaluate the effects of RNH1 on apoptosis of LUAD cells. The function of RNH1 in invasion and migration was investigated by Transwell assay. Dual luciferase assay, ChIP detection, and pull-down assay were conducted to explore the association of E2F1 in the maintenance of RNH1 expression and function. The regulation of E2F1 on the functions of RNH1 in LUAD cells was explored. Mouse experiments were performed to confirm the in-vivo role of RNH1 in LUAD. mRNA sequencing indicated that RNH1 overexpression altered the expression profile of LUAD cells.

RESULTS

RNH1 expression in LUAD tissues of patients was presented in this work. Importantly, RNH1 knockdown improved the proliferation, migration and invasion abilities of cells and RNH1 overexpression produced the opposite effects. Dual luciferase assay proved that E2F1 bound to the RNH1 promoter (-1064 ∼ -1054, -1514 ∼ -1504) to reduce the transcriptional activity of RNH1. ChIP assay indicated that E2F1 DNA was enriched at the RNH1 promoter (-1148 ∼ -943, -1628 ∼ -1423). Pull-down assays also showed the association between E2F1 and RNH1 promoter (-1148 ∼ -943). E2F1 overexpression contributed to the malignant behavior of LUAD cells, while RNH1 overexpression reversed it. High-throughput sequencing showed that RNH1 overexpression induced multiple genes expression changes, thereby modulating LUAD-related processes.

CONCLUSION

Our study demonstrates that binding of E2F1 to the RNH1 promoter may lead to inhibition of RNH1 expression and thus promoting the development of LUAD.

Long non-coding RNAs in lung cancer: Unraveling the molecular modulators of MAPK signaling

Lung cancer (LC) continues to pose a significant global medical burden, necessitating a comprehensive understanding of its molecular foundations to establish effective treatment strategies. The mitogen-activated protein kinase (MAPK) signaling system has been scientifically associated with LC growth; however, the intricate regulatory mechanisms governing this system remain unknown. Long non-coding RNAs (lncRNAs) are emerging as crucial regulators of diverse cellular activities, including cancer growth. LncRNAs have been implicated in LC, which can function as oncogenes or tumor suppressors, and their dysregulation has been linked to cancer cell death, metastasis, spread, and proliferation. Due to their involvement in critical pathophysiological processes, lncRNAs are gaining attention as potential candidates for anti-cancer treatments. This article aims to elucidate the regulatory role of lncRNAs in MAPK signaling in LC. We provide a comprehensive review of the key components of the MAPK pathway and their relevance in LC, focusing on aberrant signaling processes associated with disease progression. By examining recent research and experimental findings, this article examines the molecular mechanisms through which lncRNAs influence MAPK signaling in lung cancer, ultimately contributing to tumor development.

LINC00638 promotes the progression of non-small cell lung cancer by regulating the miR-541-3p/IRS1/PI3K/Akt axis

Background

Preceding works reveal the function of long non-coding RNAs (abbreviated to lncRNAs) during non-small cell lung cancer (NSCLC) evolvement. We explored the profile and biological functions of the lncRNA LINC00638 in NSCLC.

Methods

Reverse transcription-quantitative PCR examined LINC00638 level in NSCLC and corresponding non-tumor tissues, human normal lung epithelial cells BEAS-2B, and NSCLC cells (NCI-H460, HCC-827, A549, H1299, H1975, H460). The gain- and loss-of-function assay of LINC00638 ascertained its function in modulating the proliferation, apoptosis, and invasion of NSCLC cells (HCC-827 and H460). Bioinformatics analysis investigated the underlying mechanisms. Dual luciferase reporter gene and RNA immunoprecipitation (RIP) checked the interactions between LINC00638 and microRNA (miR)-541-3p, miR-541-3p and insulin receptor substrate 1 (IRS1).

Results

LINC00638 was upregulated in NSCLC tissues by contrast to the profiles found in the corresponding non-tumor normal tissues, as well as in NSCLC cells vis-à-vis BEAS-2B cells. LINC00638 upregulation pertained to the poorer survival rates of NSCLC patients. Overexpressing LINC00638 augmented NSCLC cells' proliferation, growth, migration, and invasion but inhibited their apoptosis, while down-regulating LINC00638 led to the opposite. miR-541-3p might be an underlying target of LINC00638, which targeted IRS1, inhibited NSCLC progression, and reversed the carcinogenic effects of LINC00638. Mechanistically, LINC00638/miR-541-3p regulated the IRS1/phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Repressing IRS1/2 using its inhibitor NT157 repressed LINC00638-mediated oncogenic effects.

Conclusion

LINC00638 may function as an oncogene in NSCLC by modulating the miR-541-3p/IRS1/PI3K/Akt axis.

LncRNA-ZXF1 stabilizes P21 expression in endometrioid endometrial carcinoma by inhibiting ubiquitination-mediated degradation and regulating the miR-378a-3p/PCDHA3 axis

Long noncoding RNAs (lncRNAs) have a profound effect on biological processes in various malignancies. However, few studies have investigated their functions and specific mechanisms in endometrial cancer. In this study, we focused on the role and mechanism of lncRNA-ZXF1 in endometrial cancer. Bioinformatics and in vitro and in vivo experiments were used to explore the expression and function of lncRNA-ZXF1. We found that lncRNA-ZXF1 altered the migration and invasion of endometrioid endometrial cancer (EEC) cells. Furthermore, our results suggest that lncRNA-ZXF1 regulates EEC cell proliferation. This regulation may be achieved by the lncRNA-ZXF1-mediated alteration in the expression of P21 through two mechanisms. One is that lncRNA-ZXF1 functions as a molecular sponge of miR-378a-3p to regulate PCDHA3 expression and then modulate the expression of P21. The other is that lncRNA-ZXF1 inhibits CDC20-mediated degradation of ubiquitination by directly binding to P21. To the best of our knowledge, this study is the first to explore lncRNA-ZXF1 functioning as a tumor-suppressing lncRNA in EEC. LncRNA-ZXF1 may become therapeutic, diagnostic, and prognostic indicator in the future.

DUBR suppresses migration and invasion of human lung adenocarcinoma cells via ZBTB11-mediated inhibition of oxidative phosphorylation

Long noncoding RNAs (lncRNAs) are involved in a variety of cancers, but the role of LncRNA DUBR in lung adenocarcinoma (LUAD), the most prevalent form of lung cancer, remains unclear. In this study we investigated the expression of DUBR in LUAD to ascertain its association with the clinical pathology and prognosis of LUAD. Analysis of mRNA expression in The Cancer Genome Atlas (TCGA) LUAD database and in-house LUAD cohort (n = 94) showed that DUBR was significantly downregulated in LUAD, and was associated with poor prognosis. In LUAD cell lines (H1975, A549), overexpression of DUBR significantly suppressed the migration and invasion of the LUAD cells. We demonstrated that c-Myc could bind to the promoter of DUBR, and transcriptionally suppressed its expression. Knockdown of c-Myc almost completely blocked the invasion and migration of LUAD cells, whereas knockdown of DUBR partially rescued c-Myc-knockdown suppressed cell migration and invasion. Furthermore, DUBR overexpression significantly increased the expression of a downstream protein of DUBR, zinc finger, and BTB domain containing 11 (ZBTB11), in H1975 and A549 cells; knockdown of ZBTB11 partially rescued the DUBR-overexpression suppressed cell migration and invasion; knockdown of c-Myc significantly upregulated the expression of ZBTB11 in LUAD cells. Finally, we revealed that DUBR/ZBTB11 axis suppressed oxidative phosphorylation in LUAD cells. In short, we demonstrate that c-Myc/DUBR/ZBTB11 axis suppresses migration and invasion of LUAD by attenuating cell oxidative phosphorylation, which provides new insights into the regulatory mechanism of DUBR.

LINC01089 suppresses lung adenocarcinoma cell proliferation and migration via miR-301b-3p/STARD13 axis

Background

Lung adenocarcinoma (LUAD) is one of the most common cancers with high morbidity and mortality worldwide. Long non-coding RNAs (lncRNAs) serve as tumor promoters or suppressors in the development of various human malignancies, including LUAD. Although long intergenic non-protein coding RNA 1089 (LINC01089) suppresses the progression of breast cancer, its mechanism in LUAD requires further exploration. Thus, we aimed to investigate the underlying function and mechanism of LINC01089 in LUAD.

Methods

The expression of LINC01089 in LUAD and normal cell lines was detected. Functional assays were applied to measure cell proliferation, apoptosis and migration. Besides, mechanism experiments were employed for assessing the interplay among LINC01089, miR-301b-3p and StAR related lipid transfer domain containing 13 (STARD13). Data achieved in this study was statistically analyzed with Student’s t test or one-way analysis of variance.

Results

LINC01089 expression was significantly down-regulated in LUAD tissues and cells and its overexpression could reduce cell proliferation and migration. Moreover, LINC01089 could regulate STARD13 expression through competitively binding to miR-301b-3p in LUAD. Additionally, rescue assays uncovered that STARD13 depletion or miR-301b-3p overexpression could countervail the restraining effect of LINC01089 knockdown on the phenotypes of LUAD cells.

Conclusion

LINC01089 served as a tumor-inhibitor in LUAD by targeting miR-301b-3p/STARD13 axis, providing an innovative insight into LUAD therapies.

Trial registration Not applicable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01568-6.

Linc00426 accelerates lung adenocarcinoma progression by regulating miR-455-5p as a molecular sponge

Increasing lines of evidence indicate the role of long non-coding RNAs (LncRNAs) in gene regulation and tumor development. Hence, it is important to elucidate the mechanisms of LncRNAs underlying the proliferation, metastasis, and invasion of lung adenocarcinoma (LUAD). We employed microarrays to screen LncRNAs in LUAD tissues with and without lymph node metastasis and revealed their effects on LUAD. Among them, Linc00426 was selected for further exploration in its expression, the biological significance, and the underlying molecular mechanisms. Linc00426 exhibits ectopic expression in LUAD tissues and cells. The ectopic expression has been clinically linked to tumor size, lymphatic metastasis, and tumor differentiation of patients with LUAD. The deregulation of Linc00426 contributes to a notable impairment in proliferation, invasion, metastasis, and epithelial-mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, the deregulation of Linc00426 could reduce cytoskeleton rearrangement and matrix metalloproteinase expression. Meanwhile, decreasing the level of Linc00426 or increasing miR-455-5p could down-regulate the level of UBE2V1. Thus, Linc00426 may act as a competing endogenous RNA (ceRNA) to abate miR-455-5p-dependent UBE2V1 reduction. We conclude that Linc00426 accelerates LUAD progression by acting as a molecular sponge to regulate miR-455-5p, and may be a potential novel tumor marker for LUAD.

lnc-REG3G-3-1/miR-215-3p Promotes Brain Metastasis of Lung Adenocarcinoma by Regulating Leptin and SLC2A5

This study aims to explore the role and mechanism of specific lncRNA in brain metastasis (BM) from lung adenocarcinoma (LADC), providing an effective biomarker for early diagnosis and targeted therapy of BM from LADC. Based on the gene expression profiles of lncRNA and mRNA in LADC and BM tissues detected by Gene Chip, lnc-REG3G-3-1 was selected, and the related genes, including miR-215-3p, leptin, and SLC2A5, were identified by data analysis. Human LADC cell lines A549 and H1299 were cultured. Dual-luciferase and endogenous validation experiments were used to confirm the regulation between these genes. Real-time quantitative reverse transcription-polymerase chain reaction and Western blotting were used to detect gene expression. The tumor metastasis-related gene function of lnc-REG3G-3-1 and miR-215-3p in H1299 cells was verified by Transwell invasion, migration assays, and scratch testing. Nude mice xenograft tumors constructed with decreased lnc-REG3G-3-1 confirmed the influences on gene expression in vivo. lnc-REG3G-3-1 was highly expressed in BM tissues that originated from LADC compared with that in primary cancer tissues. lnc-REG3G-3-1 reduced miR-215-3p expression, thereby regulating the target genes leptin and SLC2A5 and the signaling pathways, taking part in the lnc-REG3G-3-1/miR-215-3p axis in the process of BM from LADC. lnc-REG3G-3-1, leptin, and SLC2A5 through regulating signaling pathways may be jointly involved in the regulation of the biological process of BM in patients with LADC.

A novel mechanism by which ACTA2-AS1 promotes cervical cancer progression: acting as a ceRNA of miR-143-3p to regulate SMAD3 expression

BACKGROUND

Long non-coding RNAs (LncRNAs) have been increasingly confirmed to be abnormally expressed in human cancer and closely related to tumorigenesis. LncRNA ACTA2-AS1 is abnormally expressed in multiple tumors and participates in their development. However, whether ACTA2-AS1 plays a role in the development of cervical cancer (CC) and the exact mechanism of its role has not been elucidated.

METHODS

Quantitative real-time PCR (qRT-PCR) was conducted to detect the expression level of messenger RNA of ACTA2-AS1, miR-143-3p and SMAD3 in tumor tissues and cells. Additionally, SMAD3 protein expression by western blots in cells. Small interference RNA against ACTA2-AS1 or SMAD3 and miR-143-3p mimic/inhibitor was designed and transfected into CC cell lines to investigate their correlations and potential impacts on cell function. Cell Counting Kit-8 (CCK-8) assay, colony formation, cell cycle assay, transwell assay and flow cytometry analysis were performed to detect the specific effects on cell line proliferation, metastasis and apoptosis.

RESULTS

ACTA2-AS1 was significantly increased in CC tissues and cells and miR-143-3p was down-regulated. Clinically, the higher expression of ACTA2-AS1 was significantly correlated with higher FIGO stage. Loss-of-function assay revealed that silencing of ACTA2-AS1 inhibited cell proliferation, colony formation, migration and promoted apoptosis in CC. Additionally, Pearson correlation analysis showed that the expression of ACTA2-AS1 and miR-143-3p were negatively correlated. Dual-luciferase reporter assay and further mechanistic experiments confirmed that ACTA2-AS1 could sponge and regulate the expression of miR-143-3p. Furthermore, SMAD3 was the target gene of miR-143-3p and ACTA2-AS1 could upregulate SMAD3 through acting as a competitive endogenous RNA (ceRNA) of miR-143-3p. Finally, rescue assay demonstrated that the ACTA2-AS1/miR-143-3p/SMAD3 axis played an important role in the proliferation, migration and apoptosis of CC cells.

CONCLUSIONS

In summary, our study revealed that ACTA2-AS1 upregulates SMAD3 by competitively binding miR-143-3p, thereby accelerating CC progression. The ACTA2-AS1/miR-143-3p/SMAD3 axis can play a crucial role in cervical carcinogenesis, providing new clues for the early diagnosis and treatment of CC.

Enhanced expression of lncRNA ZXF1 promotes cisplatin resistance in lung cancer cell via MAPK axis

Long non-coding RNA (lncRNA) ZXF1 has recently been associated with the poor prognosis of lung cancer by promoting metastasis. However, little is known regarding the role of ZXF1 in lung cancer treatment and the underlying mechanism. Here, using lung cancer tissue and chemoresistant lung cancer cells, we investigated the interaction of ZXF1 with the efficacy of cisplatin, the first-line chemotherapy for lung cancer. We found that ZXF1 overexpression in lung cancer tissue increased the risk of treatment failure and tumor recurrence. We also provided evidence that ZXF1 contributed to cisplatin resistance and cancer progression via activating ERK, JNK and p38-mediated MAPK signaling cascade. In contrast, deactivating MAPK pathway by ZXF1 silencing enhanced cisplatin-induced cell cycle arrest and apoptosis by activating p53/p21 axis. Moreover, ZXF1 knockdown suppressed MAPK-regulated expression of MMP-2 and MMP-9, the enzymes responsible for degrading extracellular matrix, and thus decreased the invasion and migration capability of the cells. All these changes inhibited rapid cell proliferation and restored cellular sensitivity to cisplatin treatment. Taken together, our study revealed that lncRNA ZXF1 contributes to cisplatin resistance and leads to the poor prognosis of lung cancer via activating MAPK pathway, which represents as a promising target to optimize lung cancer treatment.

Sputum long non-coding RNA biomarkers for diagnosis of lung cancer

BACKGROUND

Analysis of molecular changes in sputum may help diagnose lung cancer. Long non-coding RNAs (lncRNAs) play vital roles in various biological processes, and their dysregulations contribute to the development and progression of lung tumorigenesis. Herein, we determine whether aberrant lncRNAs could be used as potential sputum biomarkers for lung cancer.

METHODS

Using reverse transcription PCR, we measure expressions of lung cancer-associated lncRNAs in sputum of a discovery cohort of 67 lung cancer patients and 65 cancer-free smokers with benign diseases and a validation cohort of 59 lung cancer patients and 60 cancer-free smokers with benign diseases.

RESULTS

In the discovery cohort, four of the lncRNAs displayed a significantly different level in sputum of lung cancer patients vs.cancer-free smokers with benign diseases (all P< 0.001). From the four lncRNAs, three lncRNAs (SNHG1, H19, and HOTAIR) are identified as a biomarker panel, producing 82.09% sensitivity and 89.23% specificity for diagnosis of lung cancer. Furthermore, the biomarker panel has a higher sensitivity (82.09% vs. 52.24%, P= 0.02) and a similar specificity compared with sputum cytology (89.23% vs. 90.77%, P= 0.45). In addition, the lncRNA biomarker panel had a higher sensitivity (87.50% vs. 70.07%, p= 0.03) for diagnosis of squamous cell carcinoma compared with adenocarcinoma of the lung, while maintaining the same specificity (89.23%). The potential of the sputum lncRNA biomarkers for lung cancer detection is confirmed in the validation cohort.

CONCLUSION

We have for the first time shown that the analysis of lncRNAs in sputum might be a noninvasive approach for diagnosis of lung cancer.

Long non-coding RNAs in non-small cell lung cancer: functions and distinctions from other malignancies

Lung cancer leads to the most cancer-related death in the world. It was shown from the increasing evidences that long non-coding RNAs (lncRNAs) are emerging as molecules for diagnosis, prognosis and even therapy of lung cancer and other malignancies. The biological functions or involved signaling pathways of lncRNAs are always found to be inconsistent among different types of malignancies. However, no available literature has systemically summarized differences in the functions and underlying molecular mechanisms of lncRNAs between lung cancer and other cancers. In this review, the biological functions and molecular mechanisms of lncRNAs in lung cancer were introduced. Furthermore, their functional differences between lung cancer and other malignancies were discussed. Finally, their potential clinical applications in future lung cancer therapy were focused on.

Long non‑coding RNAs in lung cancer: Regulation patterns, biologic function and diagnosis implications (Review)

Lung cancer is the most common malignancy with the highest mortality worldwide. Emerging research has demonstrated that long non-coding RNAs (lncRNAs), a key genomic product, are commonly dysregulated in lung cancer and have significant functions in lung cancer initiation, progression and therapeutic response. lncRNAs may interact with DNA, RNA or proteins, as tumor suppressor genes or oncogenes, to regulate gene expression and cell signaling pathways. In the present review, first a summary was presented of the causal effects of dysregulated lncRNAs in lung cancer. Next, the function and specific mechanisms of lncRNA-mediated tumorigenesis, metastasis and drug resistance in lung cancer were discussed. Finally, the potential roles of lncRNAs as biomarkers for lung cancer were explored.

Upregulation of the long non-coding RNA CBR3-AS1 predicts tumor prognosis and contributes to breast cancer progression

Breast cancer is the most common female malignancy and the major cause of cancer-related death in women. Long non-coding RNAs (lncRNAs), as oncogenic or tumor suppressor factor, involved in the development and progression of various cancers. In this study, we sought to investigate the function of lncRNA CBR3-AS1 in breast cancer. We evaluated the expression pattern of CBR3-AS1 in breast cancer tissues and cell lines, explored the correlation between CBR3-AS1 expression and the survival time of breast cancer patients, and probed the effect of CBR3-AS1 on tumor progression of breast cancer through loss-of-function and gain-of-function strategies. Our results showed that CBR3-AS1 was overexpressed in breast cancer tissues and cell lines and predicted the prognosis of breast cancer patients. And CBR3-AS1 exerted biological function as an oncogenic lncRNA, involved in the regulation of cell proliferation, colony formation, apoptosis and tumor growth in breast cancer. Taken together, CBR3-AS1 was up-regulated in breast cancer and promoted the risk of breast cancer. It may be a novel therapeutic target and potential prognostic marker for breast cancer.

CeNETs analysis reveals the prognostic value of a signature integration from five lncRNAs in breast cancer

BACKGROUND

The competitive endogenous RNA (ceRNA) hypothesis is a novel effective theory that can enable us to deeply understand the mechanisms of comprehensive diseases.

METHODS

In this study, we first downloaded RNAseq data and microRNA (miRNA) seq data of breast cancer from The Cancer Genome Atlas and further explored the regulation of ceRNA network in breast cancer using comprehensive bioinformatics tools.

RESULTS

The results revealed that five miRNAs, including hsa-miR-10b, hsa-miR-21, hsa-miR-183, hsa-miR-1258, and hsa-miR-3200 formed the core of ceRNA network. Moreover, five long noncoding RNAs that could competitively bind with miR-10b, respectively, named ACTA2-AS1, RP11-384P7.7, RP11-327J17.9, RP11-124N14.3, and RP11-645C24.5, were discovered as an integration signature with great potential in the prediction of survival outcomes in patients with different stages of breast cancer.

CONCLUSIONS

This indicates that these five long noncoding RNAs may be potential novel diagnostic and prognostic biomarkers of breast cancer.

MEG3: an Oncogenic Long Non-coding RNA in Different Cancers

Long noncoding RNAs (lncRNAs) have recently considered as central regulators in diverse biological processes and emerged as vital players controlling tumorigenesis. Several lncRNAs can be classified into oncogenes and tumor suppressor genes depending on their function in cancer. A maternally expressed gene 3 (MEG3) gene transcripts a 1.6 kb lncRNA whose act as an antitumor component in different cancer cells, such as breast, liver, glioma, colorectal, cervical, gastric, lung, ovarian and osteosarcoma cancer cells. The present review highlights biological function of MEG3 to repress tumor through regulating the major tumor suppressor genes p53 and Rb, inhibiting angiogenesis-related factor, or controlling miRNAs. On the other hand, previous studies have also suggested that MEG3 mediates epithelial-mesenchymal transition (EMT). However, deregulation of MEG3 is associated with the  development and progression of cancer, suggesting that MEG3 may function as a potential biomarker and therapeutic target for human cancers.

Knockdown of ACTA2‑AS1 promotes liver cancer cell proliferation, migration and invasion

Long noncoding RNAs (lncRNAs) are important regulators of various cellular and biological processes. The present study aimed to investigate the functions of a novel lncRNA, ACTA2‑AS1:4, a transcript variant of smooth muscle α‑actin 2‑antisense 1 (ACTA2‑AS1), in regulating liver cancer progression. Expression of lncRNAs in liver cancer tissues and cell lines were analyzed by reverse transcription quantitative polymerase chain reaction (RT‑qPCR). Knockdown of ACTA2‑AS1:4 expression in LM3 liver cancer cells was achieved by transfection with small interfering RNAs (siRNAs) that specifically targeted ACTA2‑AS1:4. The proliferation and cell cycle progression of ACTA2‑AS1:4‑silenced LM3 cells were determined using MTS assay and flow cytometry, respectively. A Transwell system assay was used to evaluate the migration and invasion capacities of LM3 cells transfected with ACTA2‑AS1:4 siRNA. The expression levels of major genes associated with important cellular processes were finally determined by RT‑qPCR and western blot analysis. ACTA2‑AS1:4 expression in liver cancer tissues and multiple cell lines was markedly downregulated by specific siRNAs. This inhibition of ACTA2‑AS1:4 expression significantly promoted the proliferation, cell cycle progression, migration and invasion of LM3 cells. A decrease in ACTA2‑AS1:4 expression also suppressed E‑cadherin expression, increased N‑cadherin expression, decreased caspase 3 expression and increased cyclin D1 and matrix metalloproteinase expression in liver cancer cells. Downregulation of ACTA2‑AS1:4 affects a number of key mechanisms involved in liver cancer progression. These data may be important for the future of liver cancer diagnosis and subsequent treatments.

Potential clinical application of lncRNAs in non-small cell lung cancer

Lung cancer has been identified as one of the most prevalent and deadly tumors worldwide. In recent years, lncRNAs have been demonstrated to play a significant role in the development of lung cancer. Specifically, lncRNAs act as a regulator of cancer-critical genes, and they regulate the biological behavior of tumors at the transcriptional and posttranscriptional levels. Recent studies have shown that lncRNAs possess great potential in the treatment of non-small cell lung cancer patients because of their roles in diverse cellular processes, such as proliferation, metastasis, stem cell maintenance, and epithelial to mesenchymal transition, and they serve as signaling biomarkers. Compared to other invasive diagnostic methods, detection of lncRNAs may become a very useful noninvasive methodology. Moreover, lncRNAs can serve as potential therapeutic targets in non-small cell lung cancer due to their roles in regulating many signaling pathways associated with lung carcinoma. In this review, we discuss the roles and expression profile of lncRNAs. We also discuss the promising application of lncRNAs as predictors of clinical diagnosis, prognosis, and as potential therapeutic targets, aiming to demonstrate their practical value for clinical treatment.

lncRNA LOC100132354 promotes angiogenesis through VEGFA/VEGFR2 signaling pathway in lung adenocarcinoma

Purpose

This study aimed to study the biological function and the molecular mechanisms associated with the promotion of angiogenesis by lncRNA LOC100132354 in lung adenocarcinoma (LAD).

Patients and methods

The mRNA expression levels of 100 pairs of LAD and normal tissue samples of LOC100132354, vascular endothelial growth factor A (VEGFA), VEGF receptor-2 (VEGFR2), basic fibroblast growth factor (bFGF), and thrombospondin-1 (TSP-1) were analyzed by qPCR. LOC100132354 was knockdown and overexpressed in SPCA-1 and A549 cell lines to analyze the protein and mRNA expression levels of VEGFA, VEGFR2, bFGF, TSP-1, and changes in protein expression levels of Ras, P-A-Raf, P-B-Raf, P-C-Raf, P-Mekl/2, and P-Erk1/2. Tumor microvessel density (MVD) was analyzed in experimental nude mice.

Results

The qPCR results showed that the mRNA expression levels of LOC100132354, VEGFA, VEGFR2, and bFGF mRNA in LAD tissues were significantly increased, while TSP-1 mRNA was significantly decreased compared with the adjacent tissues. Survival analysis showed that VEGFA, VEGFR2, and bFGF were poor predictors, while TSP-1 was a good predictor in LAD. Knockdown or overexpression of LOC100132354 affected the expression levels of bFGF, VEGFA/VEGFR2 signaling pathway, and downstream target molecules, such as Ras, P-A-Raf, P-B-Raf, P-C-Raf, P-Mekl/2, and P-Erk1/2, while decreased TSP-1. After knockdown or overexpression of VEGFA expression, no significant changes in the expression level of LOC100132354 were found. Tumorigenesis of nude mice confirmed that LOC100132354 can significantly increase the tumor MVD.

Conclusion

These findings suggest VEGFA was a downstream target gene of LOC100132354, promoting angiogenesis through VEGFA/VEGFR2 signaling pathway and downstream target molecules in LAD. So, LOC100132354 is considered as an antiangiogenic target in LAD.

LINK-A promotes cell proliferation through the regulation of aerobic glycolysis in non-small-cell lung cancer

PURPOSE

Non-small-cell lung cancer (NSCLC) is the one of the most common malignancies worldwide, and occurs at a higher frequency in male individuals. Little is known about the role of the long intergenic noncoding RNA for kinase activation (LINK-A) in NSCLC, so in the present study we assessed its potential role on cell proliferation in NSCLC.

METHODS

Expression levels of LINK-A in NSCLC tissues and cell lines were detected by quantitative reverse-transcription polymerase chain reaction. LINK-A was knocked down and overexpressed separately in A549 cells and NCI-H1299 cells. The effect of LINK-A expression on cell proliferation was determined by MTT assay. The correlation between LINK-A and hexokinase II (HKII) expression was investigated by Western blot and HKII Activity Assay. Glucose consumption and lactate production assay were used to investigate the aerobic glycolysis in NSCLC cells. The effect of LINK-A in vivo was determined by xenograft assay.

RESULTS

LINK-A expression levels were increased in NSCLC tissues compared with normal tissues. Moreover, LINK-A expression was positively correlated with NSCLC clinicopathological characteristics and survival rate, while knockdown of LINK-A reduced NSCLC cell proliferation. LINK-A expression was also positively correlated with HKII, and NSCLC cells with low LINK-A expression were found to have significantly reduced HKII protein expression, accompanied by a reduction in enzyme activity levels. Both in vitro and in vivo experiments showed that LINK-A expression affected glucose consumption and lactate production through regulation of HKII expression.

CONCLUSION

These data suggest that the functions of LINK-A in NSCLC might play a key role in tumor progression and that LINK-A could be a promising predictive biomarker and potential therapeutic target for NSCLC.

A Plasma Long Noncoding RNA Signature for Early Detection of Lung Cancer

The early detection of lung cancer is a major clinical challenge. Long noncoding RNAs (lncRNAs) have important functions in tumorigenesis. Plasma lncRNAs directly released from primary tumors or the circulating cancer cells might provide cell-free cancer biomarkers. The objective of this study was to investigate whether the lncRNAs could be used as plasma biomarkers for early-stage lung cancer. By using droplet digital polymerase chain reaction, we determined the diagnostic performance of 26 lung cancer–associated lncRNAs in plasma of a development cohort of 63 lung cancer patients and 33 cancer-free individuals, and a validation cohort of 39 lung cancer patients and 28 controls. In the development cohort, 7 of the 26 lncRNAs were reliably measured in plasma. Two (SNHG1 and RMRP) displayed a considerably high plasma level in lung cancer patients vs. cancer-free controls (all P < .001). Combined use of the plasma lncRNAs as a biomarker signature produced 84.13% sensitivity and 87.88% specificity for diagnosis of lung cancer, independent of stage and histological type of lung tumor, and patients' age and sex (all P > .05). The diagnostic value of the plasma lncRNA signature for lung cancer early detection was confirmed in the validation cohort. The plasma lncRNA signature may provide a potential blood-based assay for diagnosing lung cancer at the early stage. Nevertheless, a prospective study is warranted to validate its clinical value.

[Advances in Long Non-coding RNAs on Resistant to EGFR-TKIs in Non-small Cell Lung Cancer]

Most non-small cell lung cancer patients with active epidermal growth factor receptor (EGFR) mutation will eventually acquire drug resistant to EGFR tyrosine kinase inhibitors, such as gefitinib, resulting in disease progression, which involves a variety of complex mechanisms. Up to now, the molecular mechanisms of long non-coding RNAs mediated EGFR-TKIs resistance remains poorly understood. This review aims to outline the current state of information on lncRNAs and progress on its role in EGFR-TKIs resistance in non-small cell lung cancer.

Relapse-related long non-coding RNA signature to improve prognosis prediction of lung adenocarcinoma

Increasing evidence has highlighted the important roles of dysregulated long non-coding RNA (lncRNA) expression in tumorigenesis, tumor progression and metastasis. However, lncRNA expression patterns and their prognostic value for tumor relapse in lung adenocarcinoma (LUAD) patients have not been systematically elucidated. In this study, we evaluated lncRNA expression profiles by repurposing the publicly available microarray expression profiles from a large cohort of LUAD patients and identified specific lncRNA signature closely associated with tumor relapse in LUAD from significantly altered lncRNAs using the weighted voting algorithm and cross-validation strategy, which was able to discriminate between relapsed and non-relapsed LUAD patients with sensitivity of 90.9% and specificity of 81.8%. From the discovery dataset, we developed a risk score model represented by the nine relapse-related lncRNAs for prognosis prediction, which classified patients into high-risk and low-risk subgroups with significantly different recurrence-free survival (HR=45.728, 95% CI=6.241-335.1; p=1.69e-04). The prognostic value of this relapse-related lncRNA signature was confirmed in the testing dataset and other two independent datasets. Multivariable Cox regression analysis and stratified analysis showed that the relapse-related lncRNA signature was independent of other clinical variables. Integrative in silico functional analysis suggested that these nine relapse-related lncRNAs revealed biological relevance to disease relapse, such as cell cycle, DNA repair and damage and cell death. Our study demonstrated that the relapse-related lncRNA signature may not only help to identify LUAD patients at high risk of relapse benefiting from adjuvant therapy but also could provide novel insights into the understanding of molecular mechanism of recurrent disease.

Prognostic value of lncRNAs in lung carcinoma: a meta-analysis

Many different long non-coding RNAs (lncRNAs) have been reported to be abnormally expressed in lung carcinoma and may thus serve as prognostic biomarkers for this disease. We conducted this meta-analysis, which included a total of 30 studies identified via searches of PubMed, Embase, Medline, and Web of Science and included 2912 patients from China (28), Germany (1), and Japan (1), to investigate the prognostic value of different lncRNAs in lung carcinoma. The results revealed that lncRNA transcription levels were significantly associated with overall survival in lung cancer patients (HR:1.46, 95% CI: 1.16-1.83, P = 0.000). However, lncRNA transcription levels were not associated with progression-free survival (PFS) (HR: 1.55, 95% CI: 0.50-4.80, P = 0.449). Further analysis showed that high lncRNA transcription levels were significantly associated with tumour-node-metastasis (TNM) stage (III/IV vs I/II: RR = 1.339, 95% CI: 1.046-1.716, P = 0.012), lymph node metastasis (positive vs negative: RR = 1.442, 95% CI: 1.103-1.885, P = 0.007), and distant metastasis (yes vs no: RR = 3.187,95% CI: 1.393-7.294, P = 0.006). Taken together, the results of our present meta-analysis revealed that lncRNAs may be useful prognostic markers for lung carcinoma and may also have value as biomarkers for TNM stage, lymph node metastasis and distant metastasis.

Overexpression of lncRNA IGFBP4-1 reprograms energy metabolism to promote lung cancer progression

BACKGROUND

Reprogrammed energy metabolism as an emerging hallmark of cancer has recently drawn special attention since it facilitate cell growth and proliferation. Recently, long noncoding RNAs (lncRNAs) have been served as key regulators implicated in tumor development and progression by promoting proliferation, invasion and metastasis. However, the associations of lncRNAs with cellular energy metabolism in lung cancer (LC) need to be clarified.

METHODS

Here, we conducted bioinformatics analysis and found insulin-like growth factor binding protein 4-1 (IGFBP4-1) as a new candidate lncRNA located in the upstream region of IGFBP4 gene. The expression levels of lnc-IGFBP4-1, mRNA levels of IGFBP4 in 159 paired lung cancer samples and adjacent, histological normal tissues by qRT-PCR. Over-expression and RNA interference (RNAi) approaches were adopted to investigate the biological functions of lnc-IGFBP4-1. The intracellular ATP level was measured using the Cell Titer-Glo Luminescent Cell Viability Assay kit, and changes in metabolic enzymes were examined in cancer cells and normal pulmonary epithelial cells with qRT-PCR.

RESULTS

Our results showed that lnc-IGFBP4-1 was significantly up-regulated in LC tissues compared with corresponding non-tumor tissues (P < 0.01), and its expression level was significantly correlated with TNM stage (P < 0.01) and lymph node metastasis (P < 0.05). Further investigation showed that overexpression of lnc-IGFBP4-1 significantly promoted LC cell proliferation in vitro and in vivo, while downregulation of endogenous lnc-IGFBP4-1 could inhibited cell proliferation and induce apoptosis. Moreover, we found lnc-IGFBP4-1 could influences ATP production levels and expression of enzymes including HK2, PDK1 and LDHA, in addition, decline in both ATP production and these enzymes in response to 2-DG and 2-DG-combined Rho123, respectively, was observed in lnc-IGFBP4-1-overespressing LC cells, indicative of an enhanced aerobic glycolysis rate. Finally, lnc-IGFBP4-1 was observed to negatively correlate with gene IGFBP4, and lower expression level of IGFPB4 was found after lnc-IGFBP4-1-overexpression was transfected into PC9 cells, higher expression level of IGFPB4 was also found after lnc-IGFBP4-1-downregulation was transfected into GLC-82 cells, which indicates that IGFBP4 may exert its targeting function regulated by lnc-IGFBP4-1.

CONCLUSIONS

Taken together, these findings provide the first evidence that lnc-IGFBP4-1 is significantly up-regulated in LC tissues and plays a positive role in cell proliferation and metastasis through possible mechanism of reprogramming tumor cell energy metabolism, which suggests that lnc-IGFBP4-1 may be a promising biomarker in LC development and progression and as a potential therapeutic target for LC intervention.

Upregulation of long non-coding RNA DQ786243 promotes the progression of gastric cancer

Long non-coding RNAs (lncRNAs) have been identified as key regulatory factors in various biological processes. Their dysregulation has been observed in several types of human cancer, including gastric cancer (GC). The aim of the present study was to investigate the putative roles of the lncRNA DQ786243 in the progression of GC, as well as evaluate its diagnostic and therapeutic potential in GC. The expression of DQ786243 in 82 pairs of GC tissues and adjacent healthy tissues, as well as in three GC cell lines and a human normal gastric epithelial cell line, was assessed using reverse transcription-quantitative polymerase chain reaction. In addition, the putative correlation between the expression of DQ786243 and various clinicopathological features of GC was investigated. Furthermore, the effects of silencing DQ786243 in GC cells were examined using RNA interference. Colony formation and Cell Counting kit-8 assays were used to evaluate the effects of DQ786243 on GC cell proliferation, and Transwell and wound healing assays were used to examine GC cell migration and invasion. The results of the present study demonstrated that the expression of DQ786243 was significantly upregulated in GC tissues and cell lines compared with healthy control tissues and cells. Correlation analysis revealed a significant association between the expression of DQ786243 and the TNM stage, tumor size, depth of invasion and presence of lymph node metastasis in patients with GC. Furthermore, silencing the DQ786243 was demonstrated to inhibit proliferation, and impair the migration and invasion of GC cells. The present results suggested that DQ786243 may function as an oncogenic regulator via promoting the proliferation and metastasis of GC cells. Therefore, DQ786243 may have potential as a novel biomarker for the diagnosis of GC, and may also be a promising candidate for the development of novel therapeutic approaches for the treatment of patients with GC.

Differential expression analysis at the individual level reveals a lncRNA prognostic signature for lung adenocarcinoma

BACKGROUND

Deregulations of long non-coding RNAs (lncRNAs) have been implicated in cancer initiation and progression. Current methods can only capture differential expression of lncRNAs at the population level and ignore the heterogeneous expression of lncRNAs in individual patients.

METHODS

We propose a method (LncRIndiv) to identify differentially expressed (DE) lncRNAs in individual cancer patients by exploiting the disrupted ordering of expression levels of lncRNAs in each disease sample in comparison with stable normal ordering. LncRIndiv was applied to lncRNA expression profiles of lung adenocarcinoma (LUAD). Based on the expression profile of LUAD individual-level DE lncRNAs, we used a forward selection procedure to identify prognostic signature for stage I-II LUAD patients without adjuvant therapy.

RESULTS

In both simulated data and real pair-wise cancer and normal sample data, LncRIndiv method showed good performance. Based on the individual-level DE lncRNAs, we developed a robust prognostic signature consisting of two lncRNA (C1orf132 and TMPO-AS1) for stage I-II LUAD patients without adjuvant therapy (P = 3.06 × 10^-6, log-rank test), which was confirmed in two independent datasets of GSE50081 (P = 1.82 × 10^-2, log-rank test) and GSE31210 (P = 7.43 × 10^-4, log-rank test) after adjusting other clinical factors such as smoking status and stages. Pathway analysis showed that TMPO-AS1 and C1orf132 could affect the prognosis of LUAD patients through regulating cell cycle and cell adhesion.

CONCLUSIONS

LncRIndiv can successfully detect DE lncRNAs in individuals and be applied to identify prognostic signature for LUAD patients.

Increased MIR31HG lncRNA expression increases gefitinib resistance in non-small cell lung cancer cell lines through the EGFR/PI3K/AKT signaling pathway

The aim of the present study was to gain insight into the molecular mechanism of gefitinib resistance in non-small cell lung cancer (NSCLC), and demonstrate whether long noncoding RNA (lncRNA) expression signatures differ between gefitinib-sensitive PC9 and gefitinib-resistant PC9 (PC9-R) cell lines. PC9 and PC9-R cells were treated with gefitinib and, after 48 h, proliferation and apoptosis were analyzed using a Cell Counting Kit-8 (CCK-8) assay and flow cytometry. Microarray expression profiling of lncRNAs was undertaken in both PC9 and PC9-R cells, and the expression profiles were verified by reverse transcription quantitative-polymerase chain reaction. The EGFR/PI3K/AKT signaling pathway and mitochondrial apoptosis protein expression levels were assessed by western blot analysis. The PC9 cell line treated with gefitinib had a more significant effect on cell viability and apoptosis than the PC9-R cell line (P<0.05). Expression of various lncRNAs differed significantly between the two cell lines, and MIR31HG expression in particular was significantly higher in PC9-R cells. As expected, MIR31HG lncRNA knockdown sensitized PC9-R cells to gefitinib, and further experiments revealed that turning off the EGFR/PI3K/AKT signaling pathway activated expression of p53 in PC9-R cells transfected with si-MIR31HG. Furthermore, PC9-R cells transfected with si-MIR31HG induced cell apoptosis through the mitochondrial apoptosis pathway, and arrested the cell cycle in the G0/G1 phase. The results of the current study suggest that MIR31HG lncRNA levels in PC9-R cells are higher than in PC9 cells. Furthermore, overexpression of MIR31HG lncRNAs may contribute to gefitinib resistance in PC9-R cells through the EGFR/PI3K/AKT pathway, which impacts on cell proliferation, apoptosis and the cell cycle. MIR31HG lncRNA may therefore be a novel candidate biomarker for future therapeutic strategies involving EGFR-TKIs.

The prognostic significance of long noncoding RNAs in non-small cell lung cancer: a meta-analysis

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. The overall 5-year survival rate of patients is extremely low and to find a new marker is urgently needed. Numerous studies indicate that long noncoding RNAs (lncRNAs) abnormally express in cancers. However, the results have been disputed, especially in the aspects of tumor prognosis. Therefore, we performed this meta-analysis to systematically summarize the relationship between lncRNAs expression and NSCLC. A total of 34 eligible studies including 30 on overall survival, 10 on progression-free survival and 23 on clinicopathological features were identified from the databases. Our results indicated that the levels of lncRNAs were associated with the overall survival (OS; hazard ratios [HR], 1.43; 95% confidence interval [95% CI], 1.17-1.76; P < 0.001). However, there was no relationship between lncRNAs and progression-free survival (PFS; hazard ratios [HR], 1.55; 95% confidence interval [95% CI], 0.91-2.63; P = 0.11). Moreover, lncRNAs were related to lymph node metastasis (odds ratios [OR], 1.70; 95% confidence interval [95% CI], 1.03-2.80; P = 0.04), while no association was observed with other characteristics. In conclusion, our present meta-analysis indicated that lncRNAs transcription levels may serve as a promising marker for prognosis of patients with NSCLC.

Global Prioritizing Disease Candidate lncRNAs via a Multi-level Composite Network

LncRNAs play pivotal roles in many important biological processes, but research on the functions of lncRNAs in human disease is still in its infancy. Therefore, it is urgent to prioritize lncRNAs that are potentially associated with diseases. In this work, we developed a novel algorithm, LncPriCNet, that uses a multi-level composite network to prioritize candidate lncRNAs associated with diseases. By integrating genes, lncRNAs, phenotypes and their associations, LncPriCNet achieves an overall performance superior to that of previous methods, with high AUC values of up to 0.93. Notably, LncPriCNet still performs well when information on known disease lncRNAs is lacking. When applied to breast cancer, LncPriCNet identified known breast cancer-related lncRNAs, revealed novel lncRNA candidates and inferred their functions via pathway analysis. We further constructed the human disease-lncRNA landscape, revealed the modularity of the disease-lncRNA network and identified several lncRNA hotspots. In summary, LncPriCNet is a useful tool for prioritizing disease-related lncRNAs and may facilitate understanding of the molecular mechanisms of human disease at the lncRNA level.

Upregulation of LINC-AP2 is negatively correlated with AP2 gene expression with Turnip crinkle virus infection in Arabidopsis thaliana

A long intergenic noncoding RNA LINC - AP2 is upregulated and negatively correlated with AP2 gene expression with Turnip crinkle virus infection in Arabidopsis. Plant vegetative growth and floral reproductive structure were severely retarded and distorted in Turnip crinkle virus (TCV)-infected Arabidopsis thaliana. Compared to mock-inoculated plants, the stamen filaments were shorter in flowers of TCV-infected plants. However, TCV-infected plants can still produce normal seeds through artificial pollination, indicating both its pollen and stigma were biologically functional. From our high-throughput RNA-Seq transcriptome analysis, a floral structure-related APETALA2 (AP2) gene was found to be downregulated and its neighboring long intergenic noncoding RNAs (lincRNA), At4NC069370 (named LINC-AP2 in this study), were upregulated significantly in TCV-infected plants. This LINC-AP2 was further confirmed for its existence using 5'RACE technology. LINC-AP2 overexpression (LINC-AP2 OE) transgenic Arabidopsis plants were generated to compare with TCV-infected WT plants. TCV-infected LINC-AP2 OE plants which contained lower AP2 gene expression displayed more severe symptoms (including floral structure distortion) and higher TCV-CP gene transcript and coat protein levels. Furthermore, compared to TCV-infected WT plants, TCV-infected ap2 mutant plants failed to open their flower buds and displayed more severe viral symptoms. In conclusion, upregulation of LINC-AP2 is negatively correlated with AP2 gene expression with TCV infection in Arabidopsis.

Long Non-coding RNAs and Their Roles in Non-small-cell Lung Cancer

As a leading cause of cancer deaths worldwide, lung cancer is a collection of diseases with diverse etiologies which can be broadly classified into small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). Lung cancer is characterized by genomic and epigenomic alterations; however, mechanisms underlying lung tumorigenesis remain to be elucidated. Long non-coding RNAs (lncRNAs) are a group of non-coding RNAs that consist of ⩾200 nucleotides but possess low or no protein-coding potential. Accumulating evidence indicates that abnormal expression of lncRNAs is associated with tumorigenesis of various cancers, including lung cancer, through multiple biological mechanisms involving epigenetic, transcriptional, and post-transcriptional alterations. In this review, we highlight the expression and roles of lncRNAs in NSCLC and discuss their potential clinical applications as diagnostic or prognostic biomarkers, as well as therapeutic targets.

Long non-coding RNAs: potential new biomarkers for predicting tumor invasion and metastasis

Long non-coding RNAs (lncRNAs) play important roles in malignant neoplasia. Indeed, many hallmarks of cancer define that the malignant phenotype of tumor cells are controlled by lncRNAs. Despite a growing number of studies highlighting their importance in cancer, there has been no systematic review of metastasis-associated lncRNAs in various cancer types. Accordingly, we focus on the key metastasis-related lncRNAs and outline their expression status in cancer tissues by reviewing the previous stuides, in order to summarize the nowadays research achivements for lncRNAs related to cancer metastasis. Medline, EMBASE, as well as PubMed databases were applied to study lncRNAs which were tightly associated with tumor invasion and metastasis. Up to now, a substantial number of lncRNAs have been found to have important biological functions. In this review, according to their various features in cancer, lncRNAs were roughly divided into three categories: promoting tumor invasion and metastasis, negative regulation of tumor metastasis and with dual regulatory roles. The present studies may establish the foundation for both further research on the mechanisms of cancer progression and future lncRNA-based clinical applications.

Long noncoding and circular RNAs in lung cancer: advances and perspectives

Better understanding and management of lung cancer are needed. Although much has been learned from known protein coding genes, long noncoding RNAs (lncRNAs), a relatively new and fast evolving large family of transcripts, have recently generated much attention for new discoveries. LncRNAs play critical regulatory functions and are emerging as new players in tumorigenesis and phenotypic determinators of lung cancer. In this review, we highlight the latest development of lncRNAs, including circular RNAs in lung cancer. We start with well-characterized lncRNAs and circular RNAs as an oncogene or tumor suppressor and then extend our discussion on the impact of SNPs in lncRNA on its functions and lung cancer risk and the clinical applications of lncRNAs as biomarkers and therapeutic targets.

Long Noncoding RNAs in Lung Cancer

Despite great progress in research and treatment options, lung cancer remains the leading cause of cancer-related deaths worldwide. Oncogenic driver mutations in protein-encoding genes were defined and allow for personalized therapies based on genetic diagnoses. Nonetheless, diagnosis of lung cancer mostly occurs at late stages, and chronic treatment is followed by a fast onset of chemoresistance. Hence, there is an urgent need for reliable biomarkers and alternative treatment options. With the era of whole genome and transcriptome sequencing technologies, long noncoding RNAs emerged as a novel class of versatile, functional RNA molecules. Although for most of them the mechanism of action remains to be defined, accumulating evidence confirms their involvement in various aspects of lung tumorigenesis. They are functional on the epigenetic, transcriptional, and posttranscriptional level and are regulators of pathophysiological key pathways including cell growth, apoptosis, and metastasis. Long noncoding RNAs are gaining increasing attention as potential biomarkers and a novel class of druggable molecules. It has become clear that we are only beginning to understand the complexity of tumorigenic processes. The clinical integration of long noncoding RNAs in terms of prognostic and predictive biomarker signatures and additional cancer targets could provide a chance to increase the therapeutic benefit. Here, we review the current knowledge about the expression, regulation, biological function, and clinical relevance of long noncoding RNAs in lung cancer.

LncRNA DQ786243 contributes to proliferation and metastasis of colorectal cancer both in vitro and in vivo

Accumulating evidence demonstrates that long non-coding RNAs (LncRNAs) play important roles in regulating gene expression and are involved in various cancers, including colorectal cancer (CRC). However, LncRNA profiles in CRC remain largely unknown. The present study aims to find the key LncRNA associated with CRC and to study its biological functions in CRC progression. We focused on LncRNA DQ786243, one of LncRNAs which promoted development of CRC from the Gene Expression Omnibus (GEO) and validated using quantitative real-time PCR among about 20 paired CRC tissues. The effects of LncRNA DQ786243 were assessed by silencing the LncRNA in vitro and in vivo Results showed that the expression level LncRNA DQ786243 was significantly higher in CRC tissues and cell lines. We also found LncRNA DQ786243 knockdown by RNA interference with siRNA significantly arrested the cell cycle in the G2/M-phase, promoted apoptosis and weaken the abilities of cell proliferation and invasion in vitro Further investigation into the mechanisms responsible for the growth inhibitory effects by DQ786243 silencing revealed that its knockdown resulted in the induction of cell cycle arrest and apoptosis through certain cell cycle-related and apoptosis-related proteins. Finally, xenograft experiments confirmed that the growth of xenograft tumours formed by CRC cells was suppressed after silencing LncRNA DQ786243 expression. In conclusion, the present study suggests that LncRNA DQ786243 is an oncogene that promotes tumour progression and leads us to propose that LncRNAs may serve as key regulatory hubs in CRC progression.

Long noncoding RNAs: new insights into non-small cell lung cancer biology, diagnosis and therapy

Recent advances in tiling array and high throughput analyses revealed that at least 87.3 % of the human genome is actively transcribed, though <3 % of the human genome encodes proteins. This unexpected truth suggests that most of the transcriptome is constituted by noncoding RNA. Among them, high-resolution microarray and massively parallel sequencing analyses identified long noncoding RNAs (lncRNAs) as nonprotein-coding transcripts. lncRNAs are largely polyadenylated and >200 nucleotides in length transcripts, involved in gene expression through epigenetic and transcriptional regulation, splicing, imprinting and subcellular transport. Although lncRNAs functions are largely uncharacterized, accumulating data indicate that they are involved in fundamental biological functions. Conversely, their dysregulation has increasingly been recognized to contribute to the development and progression of several human malignancies, especially lung cancer, which represents the leading cause of cancer-related deaths worldwide. We conducted a comprehensive review of the published literature focusing on lncRNAs function and disruption in nonsmall cell lung cancer biology, also highlighting their value as biomarkers and potential therapeutic targets. lncRNAs are involved in NSCLC pathogenesis, modulating fundamental cellular processes such as proliferation, cell growth, apoptosis, migration, stem cell maintenance and epithelial to mesenchymal transition, also serving as signaling transducers, molecular decoys and scaffolds. Also, lncRNAs represent very promising biomarkers in early-stage NSCLC patients and may become particularly useful in noninvasive screening protocols. lncRNAs may be used as predictive biomarkers for chemotherapy and targeted therapies sensitivity. Furthermore, selectively targeting oncogenic lncRNAs could provide a new therapeutic tool in treating NSCLC patients. lncRNAs disruption plays a pivotal role in NSCLC development and progression. These molecules also serve as diagnostic, prognostic and predictive biomarkers. Characterization of lncRNA genes and their mechanisms of action will enable us to develop a more comprehensive clinical approach, with the final goal to benefit our patients.

Emerging role of long noncoding RNAs in lung cancer: Current status and future prospects

Lung cancer is the leading cause of cancer-related death worldwide with a 5-year survival rate of less than 15%, despite significant advances in both diagnostic and therapeutic approaches. Combined genomic and transcriptomic sequencing studies have identified numerous genetic driver mutations that are responsible for the development of lung cancer. Importantly, these approaches have also uncovered the widespread expression of "noncoding RNAs" including long noncoding RNAs (LncRNAs), which impact biologic responses through the regulation of mRNA transcription or translation. To date, most studies of the role of noncoding RNAs have focused on LncRNAs, which regulate mRNA translation via the RNA interference pathway. Although many of their attributes, such as patterns of expression, remain largely unknown, LncRNAs have key functions in transcriptional, post-transcriptional, and epigenetic gene regulation. Recent research showed that LncRNAs regulate flowering time in the lung cancer. In this review, we discuss these investigations into long noncoding RNAs were performed almost exclusively in lung cancer. Future work will need to extend these into lung cancer and to analyze how LncRNAs interact to regulate mRNA expression. From a clinical perspective, the targeting of LncRNAs as a novel therapeutic approach will require a deeper understanding of their function and mechanism of action.

Long non-coding RNA: A new paradigm for lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Recent advances in whole genome transcriptome analysis have enabled the identification of numerous members of a novel class of non-coding RNAs, i.e., long non-coding RNAs (lncRNAs), which play important roles in a wide range of biological processes and whose deregulation causes human disease, including cancer. Herein we provide a comprehensive survey of lncRNAs associated with lung cancer, with particular focus on the functions that either facilitate or inhibit the progression of lung cancer and the pathways involved. Emerging data on the use of lncRNAs as biomarkers for the diagnosis and prognosis of cancer are also discussed. We cast this information within the wider perspective of lncRNA biogenesis and molecular functions in the cell. Relationships that exist between lncRNAs, genome-wide transcription, and lung cancer are discussed. Deepening our understanding on these processes is critical not only from a mechanistic standpoint, but also for the development of novel biomarkers and effective therapeutic targets for cancer patients.

Roles of long non-coding RNAs in gastric cancer metastasis

Gastric cancer is the second leading cause of cancer-related deaths. Metastasis, which is an important element of gastric cancer, leads to a high mortality rate and to a poor prognosis. Gastric cancer metastasis has a complex progression that involves multiple biological processes. The comprehensive mechanisms of metastasis remain unclear, though traditional regulation modulates the molecular functions associated with metastasis. Long non-coding RNAs (lncRNAs) have a role in different gene regulatory pathways by epigenetic modification and by transcriptional and post-transcription regulation. lncRNAs participate in various diseases, including Alzheimer’s disease, cardiovascular disease, and cancer. The altered expressions of certain lncRNAs are linked to gastric cancer metastasis and invasion, as with tumor suppressor genes or oncogenes. Studies have partly elucidated the roles of lncRNAs as biomarkers and in therapies, as well as their gene regulatory mechanisms. However, comprehensive knowledge regarding the functional mechanisms of gene regulation in metastatic gastric cancer remains scarce. To provide a theoretical basis for therapeutic intervention in metastatic gastric cancer, we reviewed the functions of lncRNAs and their regulatory roles in gastric cancer metastasis.

Long non-coding RNA functions in lung cancer

Numerous long non-coding RNAs (lncRNAs) have been discovered as a result of advances in sequencing methods in genomic research. Recent evidence indicates that lncRNAs may serve as gene regulators via various mechanisms, such as translational control. Dysregulation of lncRNAs contributes to the development and progression of several human diseases, notably lung cancer, which is one of the leading causes of cancer-associated death. Recent studies have identified key roles for molecules such as p53 and polycomb repressive complex 2 (PRC2) in carcinogenesis and the anti-carcinogenic action of lncRNAs. These findings point to the potential of lncRNAs as prospective diagnostic and prognostic biomarkers in lung cancer. In this review, we consider the functions of lncRNAs in translational control and discuss their involvement in lung cancer via p53, PRC2, and other pathways. We also consider the effects of modulating the levels and functions of lncRNAs. Further characterization of these lung cancer-associated lncRNAs will provide a better understanding of their potential roles as therapeutic targets.

The non-coding RNAs of the H19-IGF2 imprinted loci: a focus on biological roles and therapeutic potential in Lung Cancer

Since it was first described, the imprinted cluster 11p15.5 has been reported to be deregulated in a variety of pediatric and adult cancers including that of the lung. Both protein coding and non-coding genes functioning as oncogenes or as tumor suppressor genes reside within this cluster. Oncomirs that can function as oncogenes or as tumor suppressors have also been reported. While a complete account of the role played by the 11p15.5 imprinted cluster in lung cancer is beyond the scope of this review, we will focus on the role of the non-coding RNAs processed from the H19-IGF2 loci. A special emphasis will be given to the H19/miR-675 gene locus. Their potential diagnostic and therapeutic use in lung cancer will be described.

Functions of lncRNA HOTAIR in lung cancer

Long non-coding RNAs (lncRNAs) govern fundamental biochemical and cellular processes. lncRNA HOX transcript antisense RNA (HOTAIR) represses gene expression through recruitment of chromatin modifiers. The expression of HOTAIR is elevated in lung cancer and correlates with metastasis and poor prognosis. Moreover, HOTAIR promotes proliferation, survival, invasion, metastasis, and drug resistance in lung cancer cells. Here we review the molecular mechanisms underlying HOTAIR-mediated aggressive phenotypes of lung cancer. We also discuss HOTAIR’s potential in diagnosis and treatment of lung cancer, as well as the challenges of exploiting HOTAIR for intervention of lung cancer.

Non-coding RNAs in lung cancer

The discovery that protein-coding genes represent less than 2% of all human genome, and the evidence that more than 90% of it is actively transcribed, changed the classical point of view of the central dogma of molecular biology, which was always based on the assumption that RNA functions mainly as an intermediate bridge between DNA sequences and protein synthesis machinery. Accumulating data indicates that non-coding RNAs are involved in different physiological processes, providing for the maintenance of cellular homeostasis. They are important regulators of gene expression, cellular differentiation, proliferation, migration, apoptosis, and stem cell maintenance. Alterations and disruptions of their expression or activity have increasingly been associated with pathological changes of cancer cells, this evidence and the prospect of using these molecules as diagnostic markers and therapeutic targets, make currently non-coding RNAs among the most relevant molecules in cancer research. In this paper we will provide an overview of non-coding RNA function and disruption in lung cancer biology, also focusing on their potential as diagnostic, prognostic and predictive biomarkers.