CCAT1: an oncogenic long noncoding RNA in human cancers

LncRNA CCAT1 knockdown suppresses tongue squamous cell carcinoma progression by inhibiting the ubiquitination of PHLPP2

Tongue squamous cell carcinoma (TSCC) is prevailing malignancy in the oral and maxillofacial region, characterized by its high frequency. LncRNA CCAT1 can promote tumorigenesis and progression in many cancers. Here, we investigated the regulatory mechanism by which CCAT1 influences growth and metastasis of TSCC. Levels of CCAT1, WTAP, TRIM46, PHLPP2, AKT, p-AKT, and Ki67 in TSCC tissues and cells were assessed utilizing qRT-PCR, Western blot and IHC. Cell proliferation, migration, and invasion were evaluated utilizing CCK8, colony formation, wound healing and transwell assays. Subcellular localization of CCAT1 was detected utilizing FISH assay. m6A level of CCAT1 was assessed using MeRIP. RNA immunoprecipitation (RIP), Co-immunoprecipitation (Co-IP) and RNA pull down elucidated binding relationship between molecules. Nude mouse tumorigenesis experiments were used to verify the TSCC regulatory function of CCAT1 in vivo. Metastatic pulmonary nodules were observed utilizing hematoxylin and eosin (HE) staining. CCAT1 silencing repressed TSCC cell proliferation, migration and invasion. Expression of CCAT1 was enhanced through N6-methyladenosine (m6A) modification of its RNA, facilitated by WTAP. Moreover, IGF2BP1 up-regulated CCAT1 expression by stabilizing its RNA transcript. CCAT1 bond to PHLPP2, inducing its ubiquitination and activating AKT signaling. CCAT1 mediated the ubiquitination and degradation of PHLPP2 by TRIM46, thereby promoting TSCC growth and metastasis. CCAT1/TRIM46/PHLPP2 axis regulated proliferation and invasion of TSCC cells, implying that CCAT1 would be a novel therapeutic target for TSCC patients.

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.

Transcription factor B-MYB activates lncRNA CCAT1 and upregulates SOCS3 to promote chemoresistance in colorectal cancer

Currently, resistance to oxaliplatin (OXA) has become an important obstacle to improving the clinical outcome of patients with colorectal cancer (CRC). Moreover, long non-coding RNAs (lncRNAs) have been documented in cancer chemoresistance, and our bioinformatic analysis suggested an involvement of lncRNA CCAT1 in CRC development. In this context, this study aimed to clarify the upstream and downstream mechanisms underpinning the effect of CCAT1 in the resistance of CRC to OXA. The expression of CCAT1 and the upstream B-MYB in the CRC samples was predicted by bioinformatics analysis and then verified using RT-qPCR in CRC cell lines. Accordingly, overexpression of B-MYB and CCAT1 was observed in CRC cells. SW480 cell line was used for the construction of OXA-resistant cell line (SW480R). Ectopic expression and knockdown experiments of B-MYB and CCAT1 were conducted in SW480R cells to delineate their roles in the malignant phenotypes and half-maximal (50%) inhibitory concentration (IC₅₀) of OXA. It was found that CCAT1 promoted the resistance of CRC cells to OXA. Mechanistically, B-MYB transcriptionally activated CCAT1, which recruited DNMT1 to inhibit SOCS3 expression through elevating the SOCS3 promoter methylation. By this mechanism, the resistance of CRC cells to OXA was enhanced. Meanwhile, these in vitro findings were reproduced in vivo on xenografts of SW480R cells in nude mice. To sum up, B-MYB might promote the chemoresistance of CRC cells to OXA via regulating the CCAT1/DNMT1/SOCS3 axis.

Clinicopathological and prognostic value of long non-coding RNA CCAT1 expression in patients with digestive system cancer

Colon cancer associated transcript-1 (CCAT1) is known to play an important role in numerous types of human cancer, including bladder, prostate and ovarian cancer. However, a consistent perspective has not been established in digestive system cancer (DSC). To explore the prognostic value of CCAT1 in patients with DSC, a meta-analysis was performed. A systematic search of PubMed, Embase, Web of Science, China National Knowledge Infrastructure, Chinese Biological Medical Literature database, Cochrane Library and WanFang database was applied to select eligible articles. Pooled odds ratios (ORs) or hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were calculated to estimate the effects of CCAT1 on pathological or clinical features. A total of 1,719 patients from 12 eligible articles were enrolled in the meta-analysis. The results revealed that elevated CCAT1 expression was significantly related to larger tumor size (OR, 1.81; 95% CI, 1.31-2.48), poorer differentiation (OR, 0.45; 95% CI, 0.31-0.64), earlier lymph node metastasis (OR, 3.14; 95% CI, 2.34-4.22) and advanced TNM stage (OR, 3.08; 95% CI, 2.07-4.59). In addition, high CCAT1 expression predicted a poorer outcome for overall survival rate (HR, 2.37; 95% CI, 2.11-2.67) and recurrence-free survival rate (HR, 2.16, 95% CI, 1.31-3.57). High expression levels of CCAT1 were therefore related to unfavorable clinical outcomes of patients with DSC. These results demonstrated that CCAT1 could serve as a prognostic predictor in human DSC.

CCAT 1- A Pivotal Oncogenic Long Non-Coding RNA in Colorectal Cancer

Colorectal cancer (CRC) is ranked as the third most common cancer and second deadliest cancer in both men and women in the world. Currently, the cure rate and 5-year survival rate of CRC patients remain relatively low. Therefore, discovering a novel molecular biomarker that can be used to improve CRC screening, diagnosis, prognosis, and treatment would be beneficial. Long non-coding RNA colon cancer-associated transcript 1 (CCAT 1) has been found overexpressed in CRC and is associated with CRC tumorigenesis and treatment outcome. CCAT 1 has a high degree of specificity and sensitivity, it is readily detected in CRC tissues and is significantly overexpressed in both premalignant and malignant CRC tissues. Besides, CCAT 1 is associated with clinical manifestation and advanced features of CRC, such as lymph node metastasis, high tumor node metastasis stage, differentiation, invasion, and distant metastasis. In addition, they can upregulate oncogenic c-MYC and negatively modulate microRNAs via different mechanisms of action. Furthermore, dysregulated CCAT 1 also enhances the chemoresistance in CRC cells while downregulation of them reverses the malignant phenotypes of cancer cells. In brief, CCAT 1 serves as a potential screening, diagnostic and prognostic biomarker in CRC, it also serves as a potential therapeutic marker to treat CRC patients.

Metabolic/hypoxial axis predicts tamoxifen resistance in breast cancer

We sought in our cross-sectional study to investigate the role of metabolic/hypoxial axis in the development of tamoxifen (TMX) resistance in BC patients. Quantification of plasma LncRNA Taurine upregulated-1 (TUG-1), miRNA 186-5p (miR-186), serum Sirtuin-3 (SIRT3), Peroxisome Proliferator Activator Receptor alpha (PPAR-1 α) and Hypoxia Inducible Factor-1 (HIF-1α) was done in a cohort of patients divided into TMX-sensitive and TMX-resistant candidates. Multiple logistic regression and Receiver Operating Characteristic curve were developed for significant predictors. Plasma TUG-1 and miR-186 were significantly elevated in TMX resistant patients. Serum proteins SIRT3, PPAR-1 α and HIF-1α were deficient in TMX resistant patients compared to TMX sensitive patients, respectively. miR-186 was associated with respiratory symptoms, while, HIF-1α was associated with metastases in TMX resistant patients. Strong correlations were found between all parameters. A predictive model was constructed with TUG-1 and HIF-1α to estimate TMX resistance in BC patients with 88.3% sensitivity and 91.6% specificity. Hypoxia and metabolic dysregulations play important role in the development of TMX resistance in BC patients. Correlation between hypoxia, carcinogenesis and patient’s mortality have led to more aggressive phenotypes, increased risk of metastasis and resistance to TMX.

Long Non-Coding RNA Prostate Cancer Non-Coding RNA 1/miR-211-5p/Death Effector Domain Containing 2 Axis Affects Preeclampsia by Modulating Trophoblast Cells Proliferation and Apoptosis

Background: Preeclampsia (PE) is a pregnancy-specific hypertensive disorder that affects 5–7% of pregnant women and is characterized by edema, hypertension and proteinuria. It is one of the leading causes of morbidity and mortality in pregnant women and newborns. Evidences reveal that the expression of long non-coding RNA (lncRNA) prostate cancer non-coding RNA 1 (PRNCR1) is abnormal in PE. Therefore, we investigated the role of lncRNA PRNCR1 in PE development and its molecular mechanism. Methods: Quantitative reverse transcription PCR (qRT-PCR) was used to determine the expression levels of lncRNA PRNCR1, microRNA (miR)-211-5p and mRNA leval of death effector domain containing 2 (DEDD2). Besides, the expression level of DEDD2 was detected by western blot assay. Cell proliferation ability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, and cell apoptosis was detected by flow cytometry assay. Transwell assay was used to detect the migration and invasion of HTR-8/SVneo cells. The relationship between miR-211-5p and lncRNA PRNCR1 or DEDD2 was verified by dual luciferase reporter gene assay. Results: Over-expression of lncRNA PRNCR1 induced apoptosis, impeded proliferation, migration, invasion in HTR-8/SVneo cells. Knockdown of lncRNA PRNCR1 inhibited apoptosis, promoted cell proliferation, migration and invasion, and all these effects were offset by miR-211-5p inhibitor. The mRNA and protein levels of DEDD2 were decreased by overexpressing miR-211-5p in HTR-8/SVneo cells, while miR-211-5p inhibitor significantly increased the mRNA and protein levels of DEDD2. Conclusions: lncRNA PRNCR1 regulated cell behavior (proliferation, apoptosis, migration, and invasion) via the miR-211-5p/DEDD2 axis in HTR-8/SVneo cells. Thus, lncRNA PRNCR1 participated in the occurrence and development of PE.

Dexmedetomidine protects H9C2 rat cardiomyocytes against hypoxia/reoxygenation injury by regulating the long non-coding RNA colon cancer-associated transcript 1/microRNA-8063/Wnt/β-catenin axis

Dexmedetomidine (Dex) protects the heart from ischemia/reperfusion (I/R) injury. The differential expression of long non-coding RNAs (lncRNAs) is associated with myocardial injury, but whether the lncRNA colon cancer-associated transcript 1 (CCAT1) is associated with Dex-mediated myocardial protection remains unclear. In this study, a hypoxia/reoxygenation (H/R) H9C2 model was established to simulate the in vitro characteristics of I/R. CCAT1 and microRNA (miR)-8063 expression levels in H/R H9C2 cells pretreated with Dex were determined via quantitative reverse transcription-polymerase chain reaction. The survival and apoptotic rates of H9C2 cells were determined via cell counting kit-8 and flow cytometry assays. Wnt3a, Wnt5a, and β-catenin protein levels were measured via western blotting. Luciferase and RNA immunoprecipitation assays were used to explore the binding relationship between miR-8063 and CCAT1. Dex pretreatment increased H/R H9C2 cell viability and CCAT1 expression, while decreasing the cell apoptosis and Wnt3a, Wnt5a, and β-catenin protein levels. Knockdown of CCAT1 abolished the protective effects of Dex on H/R H9C2 cells, and the downregulation of miR-8063 expression eliminated the effect of CCAT1 knockdown. These results revealed that CCAT1, a sponge for miR-8063, is involved in Dex-mediated H9C2 cell H/R injury by negatively targeting miR-8063 and inactivating the Wnt/β-catenin pathway. Dex protects H9C2 cells from H/R impairment by regulating the lncRNA CCAT1/miR-8063/Wnt/β-catenin axis.

Oral Microbiota-Driven Cell Migration in Carcinogenesis and Metastasis

The oral cavity harbors approximately 1,000 microbial species, and both pathogenic and commensal strains are involved in the development of carcinogenesis by stimulating chronic inflammation, affecting cell proliferation, and inhibiting cell apoptosis. Moreover, some substances produced by oral bacteria can also act in a carcinogenic manner. The link between oral microbiota and chronic inflammation as well as cell proliferation has been well established. Recently, increasing evidence has indicated the association of the oral microbiota with cell migration, which is crucial in regulating devastating diseases such as cancer. For instance, increased cell migration induced the spread of highly malignant cancer cells. Due to advanced technologies, the mechanistic understanding of cell migration in carcinogenesis and cancer metastasis is undergoing rapid progress. Thus, this review addressed the complexities of cell migration in carcinogenesis and cancer metastasis. We also integrate recent findings on the molecular mechanisms by which the oral microbiota regulates cell migration, with emphasis on the effect of the oral microbiota on adhesion, polarization, and guidance. Finally, we also highlight critical techniques, such as intravital microscopy and superresolution microscopy, for studies in this field.

The possible role of long non-coding RNAs in recurrent miscarriage

Recurrent miscarriage (RM) is a complicated disease in reproductive medicine that impacts many families. Currently, the etiology of RM is thought to include chromosome abnormalities, reproductive tract malformations, autoimmune dysfunction, infection, and environmental factors. However, the underlying mechanisms of RM remain unknown. At present, research on long non-coding RNAs (lncRNAs) is rapidly emerging and becoming a hot research topic in epigenetic studies. Recent studies revealed that lncRNAs are strongly linked to RM and play a crucial role in epigenetic, cell cycle, cell differentiation regulation, and other life activities. This article mainly reviews the difference in lncRNA expression in patients with RM and regulation of susceptibility, endometrial receptivity, and the maternal-fetal interface. Meanwhile, the correlation between lncRNAs and RM is expounded, which provides new insights for the early diagnosis and treatment of RM.

LncRNA CCAT1 facilitates the proliferation, invasion and migration of human laryngeal squamous cell carcinoma cells via the miR-218-5p/BMI1

Long non-coding RNAs (LncRNAs) are vital in the treatment of laryngeal squamous cell carcinoma (LSCC). This study estimated the mechanism of lncRNA CCAT1 (CCAT1) in LSCC cells. The expression of CCAT1 in the human laryngeal mucosal epithelial cells (HLCs) and LSCC cells (Hep-2 and TU177) was detected. CCK-8 and Transwell assays were used to evaluate the cell proliferative, migrative, and invasive abilities, respectively. The subcellular localization of CCAT1 was verified by RNA-FISH and cytoplasmic isolation assays. The targeted relationship among CCAT1, miR-218-5p, and BMI1 was verified by dual-luciferase assay. Expressions of miR-218-5p and BMI1 were detected by RT-qPCR. Our results depicted that CCAT1 was highly-expressed in Hep-2 and TU177 cells. Silencing CCAT1 inhibited the proliferation, migration, and invasion of Hep-2 and TU177 cells. Mechanically, CCAT1 regulated the BMI1 expression by competitively binding to miR-218-5p as a competing endogenous RNA (ceRNA), and thus facilitated the growth of Hep-2 and TU177 cells. Downregulation of miR-218-5p or upregulation of BMI1 inhibited the inhibitory effect of silencing CCAT1 on Hep-2 and TU177 cell proliferation, invasion, and migration. In conclusion, our study elicited that lncRNA CCAT1 facilitated the proliferation, migration, and invasion of Hep-2 and TU177 cells by sponging miR-218-5p and regulating the downstream BMI1.

Comprehensive Analysis of Pyroptosis-Related Long Noncoding RNA Immune Infiltration and Prediction of Prognosis in Patients with Colon Cancer

Colon cancer (CC) is one of the most prevalent malignant tumours of the alimentary canal. It is unclear whether pyroptosis-related lncRNA expression is correlated with CC prognosis. We discovered 20 pyroptosis-related lncRNAs that were expressed differently in CC and normal colon tissues in our investigation. Based on differentially expressed genes (DEGs), we grouped all CC patients into two categories (Clusters 1 and 2). Cluster 1 was shown to be connected with a higher overall survival rate, upregulated expression of immune checkpoints, higher immunoscores, higher estimated scores, and immune cell infiltration. Using data from the Cancer Genome Atlas (TCGA), to create a multigene signature, the predictive significance of each lncRNA linked with pyroptosis for survival was assessed. A 9-lncRNA signature was established using the least absolute shrinkage and selection operator (LASSO) Cox regression method, and all CC patients in the TCGA cohort were classified into low-risk or high-risk groups. The low-risk CC patients had a much greater chance of survival than those in the high-risk group. The risk score is an independent prognostic indicator for predicting survival. In addition, risk characteristics are linked to immune characteristics. In summary, pyroptosis-related lncRNAs can be used to predict CC prognosis and participate in tumour immunity.

What is beyond LncRNAs in breast cancer: A special focus on colon cancer-associated Transcript-1 (CCAT-1)

Long non-coding RNAs (LncRNAs) play a vital role in the process of malignant transformation. In breast cancer (BC), lncRNAs field is currently under intensive investigations. Yet, the role of lncRNAs as promising diagnostic and/or prognostic biomarkers and as therapeutic target/tool among BC patients still needs a special focus from the biomedical scientists. In BC, triple negative breast cancer patients (TNBC) are the unlucky group as they are always represented with the worst prognosis and the highest mortality rates. For that reason, a special focus on TNBC and associated lncRNAs was addressed in this review. Colon cancer-associated transcript 1 (CCAT-1) is a newly discovered oncogenic lncRNA that has been emerged as a vital biomarker for diagnosis, prognosis and therapeutic interventions in multiple malignancies and showed differential expression among TNBC patients. In this review, the authors shed the light onto the general role of lncRNAs in BC and the specific functional activities, molecular mechanisms, competing endogenous ncRNA role of CCAT-1 in TNBC.

The Roles of the Colon Cancer Associated Transcript 2 (CCAT2) Long Non-Coding RNA in Cancer: A Comprehensive Characterization of the Tumorigenic and Molecular Functions

Colon cancer-associated transcript 2 (CCAT2) is an intensively studied lncRNA with important regulatory roles in cancer. As such, cumulative studies indicate that CCAT2 displays a high functional versatility due to its direct interaction with multiple RNA binding proteins, transcription factors, and other species of non-coding RNA, especially microRNA. The definitory mechanisms of CCAT2 are its role as a regulator of the TCF7L2 transcription factor, enhancer of MYC expression, and activator of the WNT/β-catenin pathway, as well as a role in promoting and maintaining chromosome instability through the BOP1–AURKB pathway. Additionally, we highlight how the encompassing rs6983267 SNP has been shown to confer CCAT2 with allele-specific functional and structural particularities, such as the allelic-specific reprogramming of glutamine metabolism. Additionally, we emphasize CCAT2’s role as a competitive endogenous RNA (ceRNA) for multiple tumor suppressor miRNAs, such as miR-4496, miR-493, miR-424, miR-216b, miR-23b, miR-34a, miR-145, miR-200b, and miR-143 and the pro-tumorigenic role of the altered regulatory axis. Additionally, due to its upregulation in tumor tissues, wide distribution across cancer types, and presence in serum samples, we outline CCAT2’s potential as a biomarker and disease indicator and its implications for the development of resistance against current cancer therapy regiments and metastasis.

Targeting long non coding RNA by natural products: Implications for cancer therapy

In spite of achieving substantial progress in its therapeutic strategies, cancer-associated prevalence and mortality are persistently rising globally. However, most malignant cancers either cannot be adequately diagnosed at the primary phase or resist against multiple treatments such as chemotherapy, surgery, radiotherapy as well as targeting therapy. In recent decades, overwhelming evidences have provided more convincing words on the undeniable roles of long non-coding RNAs (lncRNAs) in incidence and development of various cancer types. Recently, phytochemical and nutraceutical compounds have received a great deal of attention due to their inhibitory and stimulatory effects on oncogenic and tumor suppressor lncRNAs respectively that finally may lead to attenuate various processes of cancer cells such as growth, proliferation, metastasis and invasion. Therefore, application of phytochemicals with anticancer characteristics can be considered as an innovative approach for treating cancer and increasing the sensitivity of cancer cells to standard prevailing therapies. The purpose of this review was to investigate the effect of various phytochemicals on regulation of lncRNAs in different human cancer and evaluate their capabilities for cancer treatment and prevention.

Competitive Endogenous Role of the LINC00511/miR-185-3p Axis and miR-301a-3p From Liquid Biopsy as Molecular Markers for Breast Cancer Diagnosis

Breast cancer (BC) is the leading cause of female cancer-related mortalities. Evidence has illustrated the role of long non-coding RNAs (lncRNA) and microRNAs (miRNA) as promising pool of protein non-coding regulators, for tuning the aggressiveness of several malignancies. This research aims to unravel the expression pattern and the emphases of the diagnostic value of the long intergenic ncRNA00511 (LINC00511) and its downstream microRNA (miR-185-3p) and the pathogenic significance of the onco-miR-301a-3p in naïve BC patients. LINC00511 was chosen and validated, and its molecular binding was confirmed using bioinformatics. LINC00511 was measured in 25 controls and 70 patients using qPCR. The association between the investigated ncRNA’s expression and the BC patients’ clinicopathological features was assessed. Receiver operating characteristic (ROC) curve was blotted to weigh out their diagnostic efficacy over the classical tumor markers (TMs). Bioinformatics and Spearman correlation were used to predict the interaction between LINC00511, miR-185-3p, and miR-301a-3p altogether to patients’ features. LINC00511 and miR-301a-3p, in BC patients’ blood, were overexpressed, and their median levels increased significantly, while miR-185-3p was, in contrast, downregulated, being decreased fourfold. LINC00511 was elevated in BC early stages, when compared to late stages (p < 0.0003). LINC00511, miR-185-3p, and miR-301a-3p showed AUC superior to classical TMs, allowing us to conclude that the investigated ncRNAs, in BC patients’ liquid biopsy, are novel diagnostic molecular biomarker signatures. Lymph node metastasis (LNM) and advanced tumor grade were directly correlated with LINC00511 significantly. Additionally, both LINC00511 and miR-301a-3p were positively correlated with the aggressiveness of BC, as manifested in patients with larger tumors (>2 cm) at (p < 0.001). Therefore, these findings aid our understanding of BC pathogenesis, in the clinical setting, being related in part to the LINC00511/miR axis, which could be a future potential therapeutic target.

The Role of Non-Coding RNAs in the Regulation of the Proto-Oncogene MYC in Different Types of Cancer

Alterations in the expression level of the MYC gene are often found in the cells of various malignant tumors. Overexpressed MYC has been shown to stimulate the main processes of oncogenesis: uncontrolled growth, unlimited cell divisions, avoidance of apoptosis and immune response, changes in cellular metabolism, genomic instability, metastasis, and angiogenesis. Thus, controlling the expression of MYC is considered as an approach for targeted cancer treatment. Since c-Myc is also a crucial regulator of many cellular processes in healthy cells, it is necessary to find ways for selective regulation of MYC expression in tumor cells. Many recent studies have demonstrated that non-coding RNAs play an important role in the regulation of the transcription and translation of this gene and some RNAs directly interact with the c-Myc protein, affecting its stability. In this review, we summarize current data on the regulation of MYC by various non-coding RNAs that can potentially be targeted in specific tumor types.

LncRNA CCAT1 downregulation increases the radiosensitivity of non-small cell lung cancer cells

This study aims to investigate if the radiosensitivity of non-small cell lung cancer (NSCLC) cells can be regulated by long noncoding RNA (lncRNA) colon cancer associated transcript1 (CCAT1). CCAT1 was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in NSCLC cells (A549, H1299, SK-MES1, H460, and H647) and human bronchial epithelial cells (16HBE). H460 and A549 cells were then selected for the determination of CCAT1 expression after exposure to radiation (0, 2, 4, 6 Gy) at different time points (0, 6, 12, 24 h). Colony forming assay was performed to evaluate the effects of CCAT1 siRNA or pcDNA3.1-CCAT1 vector on the radiosensitivity of H460 and A549 cells. Then, flow cytometry, western blotting and qRT-PCR were also conducted. CCAT1 was increased in NSCLC cells when compared with 16HBE cells, which was declined in a time- and dosage-dependent manner after exposure to radiation. The H460 and A549 cell colonies were decreased and the γ-H2AX expression was elevated with the increase of radiation dosage, which was more obvious in those transfected with CCAT1 siRNA. CCAT1 downregulation arrested NSCLC cells at G2/M phase. Moreover, the enhanced apoptosis of radiotherapy-treated NSCLC cells with reductions of p-p38/p38, p-ERK/ERK, and p-JNK/JNK was promoted by siCCAT1, but it was reversed by pcDNA3.1-CCAT1 vector. Inhibiting CCAT1 regulated cell cycle, DNA damage and apoptosis of NSCLC cells, and affected MAPK pathway, eventually improving the radiosensitivity of NSCLC.

Regulation of Long Non-Coding RNAs by Plant Secondary Metabolites: A Novel Anticancer Therapeutic Approach

Simple Summary

Cancer is caused by the rapid and uncontrolled growth of cells that eventually lead to tumor formation. Genetic and epigenetic alterations are among the most critical factors in the onset of carcinoma. Phytochemicals are a group of natural compounds that play an essential role in cancer prevention and treatment. Long non-coding RNAs (lncRNAs) are potential therapeutic targets of bioactive phytochemicals, and these compounds could regulate the expression of lncRNAs directly and indirectly. Here, we critically evaluate in vitro and in vivo anticancer effects of phytochemicals in numerous human cancers via regulation of lncRNA expression and their downstream target genes.

Abstract

Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs that play an essential role in various cellular activities, such as differentiation, proliferation, and apoptosis. Dysregulation of lncRNAs serves a fundamental role in the progression and initiation of various diseases, including cancer. Precision medicine is a suitable and optimal treatment method for cancer so that based on each patient’s genetic content, a specific treatment or drug is prescribed. The rapid advancement of science and technology in recent years has led to many successes in this particular treatment. Phytochemicals are a group of natural compounds extracted from fruits, vegetables, and plants. Through the downregulation of oncogenic lncRNAs or upregulation of tumor suppressor lncRNAs, these bioactive compounds can inhibit metastasis, proliferation, invasion, migration, and cancer cells. These natural products can be a novel and alternative strategy for cancer treatment and improve tumor cells’ sensitivity to standard adjuvant therapies. This review will discuss the antineoplastic effects of bioactive plant secondary metabolites (phytochemicals) via regulation of expression of lncRNAs in various human cancers and their potential for the treatment and prevention of human cancers.

LINC00649 promotes bladder cancer malignant progression by regulating the miR‑15a‑5p/HMGA1 axis

The aim of the present study was to explore the effects of LINC00649 on the proliferation, migration and invasion of bladder cancer (BC) and identify possible mechanisms. Through TCGA database analysis of LINC00649 expression in bladder cancer and the association of LINC00649 with the BC patient prognosis, RT‑qPCR was employed for detecting LINC00649 expression in 60 clinical tissue specimens and cell lines of bladder cancer. The lentivirus stable transfection or small interfering RNA was used to increase or decrease the LINC00649 expression level in T24 and UM‑UC‑3 cells. CCK8 and clone formation assay were utilized to observe the effects of LINC00649 on the proliferation and colony formation of BC cells. Transwell experiment was performed to detect the effects of LINC00649 on the migration and invasion of bladder cancer. Bioinformatics database was used to identify the possible downstream targets of LINC00649 while RT‑qPCR, western blot analysis and dual luciferase reporter gene experiments were carried out to verify the possible molecular mechanism. The TCGA database analysis revealed a significantly high expression of LINC00649 in bladder cancer and an association of LINC00649 expression with overall survival rate of BC patients. As shown by RT‑qPCR detection, LINC00649 expression was notably upregulated in BC tissues and BC cell lines. In addition, statistical analyses unveiled that highly expressed LINC00649 was clearly associated with poor overall survival of bladder cancer. Based on the in vitro cell experiment, upregulated LINC00649 considerately enhanced the proliferation, migration and invasion of BC cells, as opposed to those in T24 and UM‑UC‑3 cells by suppressing LINC00649. Mechanically, LINC00649 may promote the malignant progression of bladder cancer by regulating miR‑15a‑5p to promote the HMGA1 expression axis. Overall, LINC00649 upregulates HMGA1 expression by binding to miR‑15a‑5p to enhance the proliferation, migration and invasion of BC cells. Thus, LINC00649 is a potential biomarker and therapeutic target for bladder cancer.

Potential diagnostic and prognostic value and regulatory relationship of long noncoding RNA CCAT1 and miR-130a-3p in clear cell renal cell carcinoma

Background

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) could interact with each other to play a vital role in the pathogenesis of cancers. We aimed to examine the expression profile, clinical significance and regulatory relationship of miR-130a-3p and its predicted interactive lncRNA in clear cell renal cell carcinoma (ccRCC).

Methods

Bioinformatics analysis was used to predict lncRNAs binding with miR-130a-3p. qRT-PCR was employed to detect the expression levels of miR-130a-3p and the miRNA-targeted lncRNA, and their clinical values in ccRCC were clarified. The lncRNA sponge potential of miR-130a-3p was assessed through dual-luciferase reporter assay and the biological effects of them were observed.

Results

Colon cancer associated transcript 1 (CCAT1) directly interacted with miR-130a-3p and negatively regulated miR-130a-3p expression. CCAT1 was upregulated and miR-130a-3p was downregulated in ccRCC cell line and tissues (all P < 0.05). High CCAT1 and low miR-130a-3p expression was correlated with larger tumor size and advanced TNM stage in ccRCC patients. High CCAT1 level suggested a poor survival prognosis. There was a negative association between CCAT1 and miR-130a-3p expression (r = − 0.373, P = 0.010). MiR-130a-3p mimic and si-CCAT1 inhibited ccRCC cell proliferation and invasion, and induced apoptosis.

Conclusions

CCAT1/miR-130a-3p axis may have potential to serve as a novel diagnostic and prognostic target of ccRCC patients.

lncRNA CCAT1/miR-490-3p/MAPK1/c-Myc positive feedback loop drives progression of acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a frequently diagnosed malignancy in adults. Long non-coding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) has been well known to play vital roles in multiple malignancies including AML. Unfortunately, the detailed mechanism of CCAT1 in AML progression remains obscure. In this study, we demonstrated that CCAT1 was up-regulated in AML samples while its target, miR-490-3p, was relatively down-regulated. CCAT1 markedly increased viability and metastasis of AML cells, while miR-490-3p had opposite effects. CCAT1 could specifically bind to miR-490-3p and reduce its expression and activity, and MAPK1 was a target gene of miR-490-3p. Overexpressed CCAT1 could induce MAPK1 expression and c-Myc reciprocally increased CCAT1 expression. Our data implied that miR-490-3p could be a novel therapeutic target for AML, and highlights the crucial role of CCAT1/miR-490-3p/MAPK1/c-Myc positive feedback loop in AML progression.

Long Non-coding RNA Colon Cancer-Associated Transcript-1 Promotes Migration, Invasion, and Epithelial Mesenchymal Transition of Lung Adenocarcinoma by Suppressing miR-219-1

Previous evidence suggests that long non-coding colon cancer-associated transcript-1(CCAT1) plays a pivotal role in the progression of a variety of tumors. However, little is known about its role in lung adenocarcinoma (LAD). In this study, we found LAD tissue samples had a higher expression of CCAT1 but a lower expression of miR-219-1 compared to their adjacent non-tumor tissues. CCAT1 negatively regulated the expression of miR-219-1. miR-219-1 suppressed the proliferation of A549 and H1299 cells. Knockdown of CCAT1 inhibited the proliferation, migration, and invasion of A549 and H1299 cells, which were reversed by the miR-219-1 inhibitor. CCAT1 knockdown increased the expression of E-cadherin but decreased the expressions of N-cadherin and vimentin, which were restored by the miR-219-1 inhibitor. In vivo, knockdown of CCAT1 suppressed the tumor growth of LAD xenografts, which were rescued by the inhibition of miR-219-1. In summary, our findings suggested that CCAT1 promotes the progression of LAD via sponging miR-219-1, providing a potential therapeutic target for LAD.

Long Non-coding RNA CCAT1 Acts as an Oncogene and Promotes Sunitinib Resistance in Renal Cell Carcinoma

Although sunitinib contributes to prolonging the progression-free survival of metastatic renal cell carcinoma significantly, the universal presence of resistance limits the initial response rate and restricts durable responses. The mechanisms involved in sunitinib resistance vary and need further investigation. We found long non-coding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) overexpressed in sunitinib-resistant cells while declined in the parental cells. Moreover, lncRNA CCAT1 increased significantly in samples with resistance to sunitinib compared with those with responses to sunitinib. The reduction of CCAT1 suppressed cell growth and colony formation while triggering apoptosis. Inversely, the ectopic expression of c-Myc reversed the inhibition of cell growth and enhancement of apoptosis by the knockdown of CCAT1. We also verified that anti-apoptosis protein B-cell lymphoma 2 (Bcl-2) and myeloid cell leukemia 1 (Mcl-1) decreased along with the deregulation of CCAT1, whereas the expression of Bcl-2 and Mcl-1 restored in cells that were transfected sh-CCAT1 and c-Myc simultaneously. Apart from the in vitro experiments, we demonstrated that knockdown of CCAT1 boosted response to sunitinib by performing sunitinib-resistant ACHN mouse models. Briefly, lncRNA CCAT1 conferred renal cell carcinoma resistance to sunitinib in a c-Myc-dependent manner, providing a novel target for improvement of sunitinib therapy.

CCAT1 promotes triple-negative breast cancer progression by suppressing miR-218/ZFX signaling

Long non-coding RNAs (lncRNAs) regulate cancer development and progression. Here, we investigated the role of the lncRNA CCAT1 in triple-negative breast cancer (TNBC). CCAT1 expression was higher in TNBC cells than normal breast epithelial cells. Additionally, CCAT1 expression was higher in TNBC patient tumor tissue than adjacent normal breast tissue. Silencing CCAT1 inhibited TNBC cell proliferation, migration, and invasion in vitro, and tumor growth and progression in vivo. Bioinformatics analysis revealed that microRNA-218 (miR-218) is a potential target of CCAT1. Silencing CCAT1 resulted in an increase in miR-218 expression and inhibited TNBC cell proliferation, migration, and invasion. Silencing miR-218 reversed the effects of CCAT1 knockdown on cell proliferation, migration, and invasion, suggesting that CCAT1 promotes TNBC progression by downregulating miR-218 expression. We identified the zinc finger protein ZFX as a putative downstream target of miR-218 through bioinformatics analysis. ZFX expression was higher in TNBC than normal breast cell lines and higher in TNBC tumor tissue than adjacent normal breast tissue. Overexpression of ZFX reversed the tumor-suppressive effects of miR-218 on TNBC cell proliferation, migration, and invasion. Our data indicate that CCAT1 promotes TNBC progression by targeting the miR-218/ZFX axis.

LncRNA & Wnt signaling in colorectal cancer

The outlook for new therapeutic approaches is pivotal to ameliorate the deterioration caused by the abrogated Wnt signaling. Long non-coding RNAs (lncRNAs) are tiny molecules that have begun emerging as vital molecular manager for the regulation of various cellular processes at transcription and translation levels in the colorectal cancer (CRC). Targeting Wnt pathway with lncRNA seems a promising approach to eradicate CRC. However, little is known of their active role in commencing both apoptosis and proliferation in CRC. This article  reviews the importance of these molecules in the pathogenesis of CRC and also emphasizes on the development of new therapeutic strategies to cope with the Wnt mediated CRC.

Long Noncoding RNA CCAT1 Functions as a Competing Endogenous RNA to Upregulate ITGA9 by Sponging MiR-296-3p in Melanoma

Background

Melanoma is aggressive and lethal melanocytic neoplasm, and its incidence has increased worldwide in recent decades. Accumulating evidence has showed that various long noncoding RNAs (lncRNAs) participated in occurrence of malignant tumors, including melanoma. The present study was designed to investigate function of lncRNA colon cancer-associated transcript-1 (CCAT1) in melanoma.

Methods

The expression levels of CCAT1, miR-296-3p and Integrin alpha9 (ITGA9) in melanoma tissues or cells were measured using real-time quantitative polymerase chain reaction (RT-qPCR). The concentrations of glucose and lactate were measured for assessing glycolysis of melanoma cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), flow cytometry, and transwell assays were conducted to assess proliferation, apoptosis, and migration of melanoma cells. Western blot assay was performed to measure the protein expression of ITGA9, hexokinase 2 (HK2), and epithelial–mesenchymal transition (EMT)-related proteins in melanoma tissues or cells. The relationship among CCAT1, miR-296-3p, and ITGA9 was predicted and confirmed by bioinformatics analysis, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assay, respectively. A xenograft experiment was established to assess the effect of CCAT1 knockdown in vivo.

Results

CCAT1 was effectively increased in melanoma tissues and cells compared with matched controls, and deficiency of CCAT1 impeded cell glycolysis, proliferation, migration while induced apoptosis, which were abrogated by knockdown of miR-296-3p in melanoma cells. In addition, our findings revealed that ITGA9 overexpression abolished miR-296-3p overexpression-induced effects on melanoma cells. Importantly, CCAT1 regulated ITGA9 expression by sponging miR-296-3p. The results of xenograft experiment suggested that CCAT1 silencing inhibited melanoma cell growth in vivo.

Conclusion

LncRNA CCAT1 promoted ITGA9 expression by sponging miR-296-3p in melanoma.

Novel role of ASH1L histone methyltransferase in anaplastic thyroid carcinoma

Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies, with an average life expectancy of ∼6 months from the time of diagnosis. The genetic and epigenetic changes that underlie this malignancy are incompletely understood. We found that ASH1-like histone lysine methyltransferase (ASH1L) is overexpressed in ATC relative to the much less aggressive and more common differentiated thyroid cancer. This increased expression was due at least in part to reduced levels of microRNA-200b-3p (miR-200b-3p), which represses ASH1L expression, in ATC. Genetic knockout of ASH1L protein expression in ATC cell lines decreased cell growth both in culture and in mouse xenografts. RNA-Seq analysis of ASH1L knockout versus WT ATC cell lines revealed that ASH1L is involved in the regulation of numerous cancer-related genes and gene sets. The pro-oncogenic long noncoding RNA colon cancer-associated transcript 1 (CCAT1) was one of the most highly (approximately 68-fold) down-regulated transcripts in ASH1L knockout cells. Therefore, we investigated CCAT1 as a potential mediator of the growth-inducing activity of ASH1L. Supporting this hypothesis, CCAT1 knockdown in ATC cells decreased their growth rate, and ChIP-Seq data indicated that CCAT1 is likely a direct target of ASH1L's histone methyltransferase activity. These results indicate that ASH1L contributes to the aggressiveness of ATC and suggest that ASH1L, along with its upstream regulator miR-200b-3p and its downstream mediator CCAT1, represents a potential therapeutic target in ATC.

Knockdown of lncRNA CCAT1 enhances sensitivity of paclitaxel in prostate cancer via regulating miR-24-3p and FSCN1

Drug resistance limits the efficacy of chemotherapy in human cancers. Previous studies reported that long noncoding RNA colon cancer-associated transcript 1 (CCAT1) regulated progression of prostate cancer (PCa). However, the potential role of CCAT1 in the sensitivity of paclitaxel (PTX) in PCa and its mechanism remain largely unknown. The PTX-resistant PCa cells were established in PC3 and DU145 cells by increasing concentrations of PTX. The expressions of CCAT1, microRNA-24-3p (miR-24-3p) and fascin1 (FSCN1) were measured by quantitative real-time polymerase chain reaction. The viability and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, flow cytometry and western blot, respectively. The interaction among CCAT1, miR-24-3p and FSCN1 was explored by luciferase activity, RNA immunoprecipitation, RNA pull-down and western blot, respectively. Results showed that the expressions of CCAT1 were up-regulated and miR-24-3p was down-regulated in PCa and PTX-resistant PCa cells (PC3-TXR and DU145-TXR). Knockdown of CCAT1 or overexpression of miR-24-3p inhibited survival rate, half maximal inhibitory concentration (IC50) of PTX but increased apoptosis in PC3-TXR and DU145-TXR cells after treatment of PTX. miR-24-3p was bound to CCAT1 and its abrogation reversed knockdown of CCAT1-mediated increase of PTX sensitivity in PC3-TXR and DU145-TXR cells. Moreover, FSCN1 restoration attenuated miR-24-3p-mediated inhibition of PTX resistance. Besides, FSCN1 level was enhanced in PCa and PTX-resistant PCa cells and regulated by CCAT1 and miR-24-3p. Our data suggested interference of CCAT1 contributed to PTX sensitivity in PCa by regulating miR-24-3p and FSCN1, indicating a novel avenue for treatment of PCa through regulating chemoresistance.

Long non‑coding RNA CCAT1 enhances human non‑small cell lung cancer growth through downregulation of microRNA‑218

Long non-coding RNAs (lncRNAs) have critical functions in non-small cell lung cancer (NSCLC) growth. In the present study, we showed that lncRNA-CCAT1 was upregulated in NSCLC tissues. High expression of lncRNA-CCAT1 was related to tumor growth and reduced survival rate. We used short hairpin RNAs (shRNAs) to inhibit the expression of lncRNA-CCAT1 in NSCLC cells. In vitro and in vivo results demonstrated that lncRNA-CCAT1 knockdown suppressed tumor proliferation and induced apoptosis. Furthermore, microRNA-218 (miR-218) was confirmed as an effective target of lncRNA-CCAT1 in NSCLC. B lymphoma Mo-MLV insertion region 1 homolog (BMI-1), which served as a downstream target of miR-218, was also inhibited by lncRNA-CCAT1 knockdown. In conclusion, the present study indicated that upregulation of lncRNA-CCAT1 in NSCLC is associated with tumor malignant potential. lncRNA-CCAT1 enhances tumor growth in NSCLC by directly inhibiting miR-218 and indirectly increasing BMI-1 expression.

CARLo-5 as an oncogenic gene in endometrial carcinoma

The long noncoding RNA CARLo-5 is dysregulated in multiple types of human cancers. High CARLo-5 is a promising predictive factor for various cancers, including endometrial carcinoma (EC). Our previous study showed that the expression level of CARLo-5 was associated with advanced FIGO stage (The International Federation of Gynecology and Obstetrics), lymph node metastasis, and the poor survival of patients with EC. In the present study, we demonstrated that the downregulation of CARLo-5 could affect the proliferation, cell cycle, migration, and invasion of EC cell lines HEC-1B and KLE cells. The oncogenic activity of CARLo-5 was also confirmed with in vivo data. Mechanistically, CARLo-5 could affect the expression of CDK/CDKN1A and MMP2/9, which have been reported to be regulated by CARLo-5 and associated with cell cycle and motility. In conclusion, this study is the first to discover the biological function and mechanism of CARLo-5 in regulating the biological characteristics of EC cells. Targeting CARLo-5 and its pathway might provide new biomarkers or potential therapies target for patients with EC. Environ. Mol. Mutagen. 61:256-265, 2020. © 2019 Wiley Periodicals, Inc.

Long noncoding RNA LINC01278 favors the progression of osteosarcoma via modulating miR-133a-3p/PTHR1 signaling

As one of the most aggressive malignancies, osteosarcoma has high risks of death. Although long noncoding RNAs (lncRNAs) may promote the osteosarcoma progression as verified, the potential molecular mechanism of lncRNAs in osteosarcoma remains unknown. Herein, we analyzed lncRNA microarray of osteosarcoma and selected LINC01278 as the study object. Then, we found that the expression of LINC01278 tested by quantitative reverse-transcription polymerase chain reaction was enhanced in tumor tissues compared with the para-carcinoma tissues and related to clinical stage, distant metastasis in osteosarcoma. In addition, the clinical outcomes were poor in osteosarcoma patients with high LINC01278 level. Moreover, LINC01278 promoted proliferation and restrained apoptosis in osteosarcoma cells. Afterward, mechanistic studies turned out that LINC01278 was a competing endogenous RNA of parathyroid hormone type 1 receptor (PTHR1) in osteosarcoma by sponging miR-133a-3p, which was considered as a tumor inhibitor in osteosarcoma. Furthermore, PTHR1 downregulation restored the impacts of inhibited miR-133a-3p on the processes in osteosarcoma cells. Our findings clarified that the carcinogenic effect of LINC01278 in osteosarcoma was mediated through miR-133a-3p/PTHR1 signaling, creating a novel insight into good targets for the therapy and prognosis of osteosarcoma.

lncRNA CCAT1 Acts as a MicroRNA-218 Sponge to Increase Gefitinib Resistance in NSCLC by Targeting HOXA1

Long non-coding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) has been reported to play important roles in the development and progression of multiple human malignancies. However, the functional role and molecular mechanism of CCAT1 on gefitinib resistance in non-small cell lung cancer (NSCLC) are largely unclear. The aim of this study is to explore the roles of CCAT1 on gefitinib resistance in NSCLC and to explore the underlying mechanisms. The quantitative real-time PCR (qRT-PCR) analysis was to investigate the expression pattern of CCAT1 in gefitinib-resistant NSCLC patient tissues and cell lines, and then the effects of CCAT1 on gefitinib resistance of NSCLC in vitro and in vivo. Furthermore, bioinformatics online program predictions and luciferase reporter assay were used to validate the association of CCAT1 and miR-218 in NSCLC cells. In this study, CCAT1 was observed to be upregulated in gefitinib-resistant patient tissues and cell lines. In vitro and in vivo experiments demonstrated that CCAT1 knockdown impaired cell proliferation and promoted the gefitinib-induced cell apoptosis. Furthermore, we demonstrated that CCAT1 acts as a sponge for miR-218, and verified that HOXA1 is a novel target of miR-218. These results suggest that CCAT1 may serve as a promising therapeutic target for the treatment of epidermal growth factor receptor (EGFR) plus NSCLC patients.

The regulation and interaction of colon cancer-associated transcript-1 and miR7-5p contribute to the inhibition of SP1 expression by solamargine in human nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a common head and neck malignancy with higher incidence in Southern China and Southeast Asia. Solamargine (SM), a steroidal alkaloid glycoside, has been shown to have anticancer properties. However, the underlying mechanism involved remains undetermined. In this study, we showed that SM inhibited the growth of NPC cells. Mechanistically, we found that solamargine decreased lncRNA colon cancer-associated transcript-1 (CCAT1) and increased miR7-5p expression. There was a reciprocal interaction of CCAT1 and miR7-5p. In addition, SM inhibited the expression of SP1 protein and promoter activity, which was strengthened by miR7-5p mimics and inhibited by overexpressed CCAT1. MiR7-5p could bind to 3'-UTR of SP1 and attenuated SP1 gene expression. Exogenously expressed SP1 feedback resisted SM-increased miR7-5p expression and more importantly reversed SM-inhibited growth of NPC cells. Finally, SM inhibited NPC tumor growth in vivo. Collectively, our results show that SM inhibits the growth of NPC cells through reciprocal regulation of CCAT1 and miR7-5p, followed by inhibition of SP1 gene expression in vitro and in vivo. The interregulation and correlation among CCAT1, miR7-5p and SP1, and the feedback regulatory loop unveil the novel molecular mechanism underlying the overall responses of SM in anti-NPC.

SP1-mediated overexpression of lncRNA LINC01234 as a ceRNA facilitates non-small-cell lung cancer progression via regulating OTUB1

Long noncoding RNAs (lncRNAs) have been confirmed to be strongly associated with the progression of various types of cancer. LncRNA LINC01234 (LINC01234) is a newly identified tumor-related lncRNA whose upregulation has been confirmed in some tumors. However, its potential expressions and possible functions in non-small-cell lung cancer (NSCLC) have not been explored. In this study, we first found that LINC01234 expressions were distinctly upregulated in both NSCLC samples and cell lines using RT-PCR. Our group also showed that LINC01234 upregulations were modulated by nuclear transcription factor SP1. The results form clinical investigations indicated that high LINC01234 expressions were associated with positively lymph node metastasis and advanced tumor-metastasis-node (TMN) stage. Kaplan-Meier assays indicated that patients with NSCLC having high LINC01234 expressions tend to have unfavorable clinical prognosis. Using multivariate assays, it was confirmed that LINC01234 was an independent prognostic factor for patients with NSCLC. In vitro assays showed that inhibition of LINC01234 suppressed NSCLC cell proliferation, cell colony formation and metastasis, and greatly promoted apoptosis. Mechanistic investigations revealed LINC01234 promotes the progression of NSCLC cells by the modulation of miR-140 to positively regulate OTUB1 expression. Taken together our findings, they provided an exhaustive assay of LINC01234 in NSCLC and imperative clues for insights into the potential effects of lncRNAs-miRNAs regulatory network in NSCLC.

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 RNA NR_002794 is upregulated in pre‑eclampsia and regulates the proliferation, apoptosis and invasion of trophoblast cells

Pre-eclampsia is a common complication during pregnancy, characterized by hypertension and proteinuria. The pathogenesis of pre-eclampsia is not fully understood. Studies on the maternal spiral artery have led scientists to consider that the ineffective infiltration of placental trophoblast cells may be a primary cause of pre-eclampsia. The present study aimed to investigate the differences in the profiles of long non-coding RNAs (lncRNAs) between the placentas of patients with pre-eclampsia and those of healthy pregnant women. The involvement of the differentially expressed lncRNAs in the biological activity of trophoblast cells was also assessed. A total of 26 differentially expressed lncRNAs were identified between the pre-eclampsia and healthy groups. Upregulation of NR_002794 was found in tissues from patients with pre-eclampsia. In SWAN71 trophoblast cells, NR_002794 had suppressive effects on proliferation and migration, and resulted in an increased rate of apoptosis. Furthermore, lncRNA NR_002794 had no effect on the phagocytosis of trophoblast cells. The present study suggested that abnormal levels of NR_002794 may lead to atypical conditions in trophoblast cells, which may be associated with the failure of maternal spiral artery remodeling during pregnancy and, consequently, with the development of pre-eclampsia.

lncRNA CCAT1 contributes to the growth and invasion of gastric cancer via targeting miR-219-1

Gastric cancer (GC) is one of the most malignant tumors that seriously threaten human health. Increased reports have indicated that long noncoding RNAs (lncRNAs) are associated with GC. This study aims to investigate the regulatory role of colon cancer-associated transcript-1 (CCAT1) in GC. The results exhibited the fact that CCAT1 was expressed higher in 57 GC tissue samples than in 57 paired adjacent normal tissue samples. The expression of CCAT1 was also increased in GC cell lines (MKN45, Hs746T, and SGC-7901) compared with the gastric epithelial cell line GES-1. Besides this, decreased cell proliferation with increased cell apoptosis was detected in SGC-7902 cells transfected with CCAT1 short hairpin RNA (shRNA). At the same time, a lower cell invasion ability was measured in SCG-7901 cells transfected with CCAT1 shRNA.In addition, miR-219-1 was predicted and convinced a direct target of CCAT1. The expression of miR-219-1 was decreased in GC tissues and GC cell lines. Further studies demonstrated that the roles of CCAT1 in cell proliferation, apoptosis, and invasion were inhibited by miR-219-1. Finally, in vivo experiment indicated that tumor growth of GC was suppressed through knockdown of CCAT1. In conclusion, these results suggested that CAT1 promotes the tumorigenesis and progression of GC by negatively regulating miR-219-1.

Long Non-Coding RNA in the Pathogenesis of Cancers

The incidence and mortality rate of cancer has been quickly increasing in the past decades. At present, cancer has become the leading cause of death worldwide. Most of the cancers cannot be effectively diagnosed at the early stage. Although there are multiple therapeutic treatments, including surgery, radiotherapy, chemotherapy, and targeted drugs, their effectiveness is still limited. The overall survival rate of malignant cancers is still low. It is necessary to further study the mechanisms for malignant cancers, and explore new biomarkers and targets that are more sensitive and effective for early diagnosis, treatment, and prognosis of cancers than traditional biomarkers and methods. Long non-coding RNAs (lncRNAs) are a class of RNA transcripts with a length greater than 200 nucleotides. Generally, lncRNAs are not capable of encoding proteins or peptides. LncRNAs exert diverse biological functions by regulating gene expressions and functions at transcriptional, translational, and post-translational levels. In the past decade, it has been demonstrated that the dysregulated lncRNA profile is widely involved in the pathogenesis of many diseases, including cancer, metabolic disorders, and cardiovascular diseases. In particular, lncRNAs have been revealed to play an important role in tumor growth and metastasis. Many lncRNAs have been shown to be potential biomarkers and targets for the diagnosis and treatment of cancers. This review aims to briefly discuss the latest findings regarding the roles and mechanisms of some important lncRNAs in the pathogenesis of certain malignant cancers, including lung, breast, liver, and colorectal cancers, as well as hematological malignancies and neuroblastoma.

LncRNA CCAT1 functions as apoptosis inhibitor in podocytes via autophagy inhibition

Podocyte apoptosis importantly contributes to various kidney diseases. Long noncoding RNAs Colon cancer‐associated transcript‐1 (CCAT‐1) has been demonstrated for a critical role in cell proliferation. In the present study, the relationship between CCAT1 and popdocyte impairment, and the underlying mechanism was investigated. Podocytes were isolated from mice and then treated with tumor necrosis factor‐α to simulate podocyte injury. After developed CCAT1 overexpression or knockdown, cell viabilities were determined with the CCK‐8 assay, apoptosis was examined with Flow cytometry, the autophagy was observed by Western blot. Furthermore, phosphorylated PI3K and Akt expressions were examined. We found that after CCAT1 overexpression, the cell viability was significantly increased, apoptosis was significantly decreased, and autophagy was significantly inhibited, which was indicated by induced P62, LC3B‐I and decreased LC3B‐II. In addition, CCAT1 overexpression induced the levels of phosphorylated PI3K and Akt. With Rap treatment, these effects by CCAT1 were reversed. Furthermore, the results contrary to the effects by CCAT1 overexpression were presented after CCAT1 knockdown, and this was inhibited by 3‐MA. Taken together, our results suggested that CCAT1 induction critically participated in apoptosis inhibition in podocytes through autophagy inhibition via increasing PI3K/Akt signaling. This might act as a promising therapeutic intervention for renal diseases associated with podocyte apoptosis.

Long Non-coding RNA Zinc Finger Antisense 1 (ZFAS1) Regulates Proliferation, Migration, Invasion, and Apoptosis by Targeting MiR-7-5p in Colorectal Cancer

Background

Colorectal cancer (CRC) is one of the most common tumors, the causes of which remain unclear. Recently, many kinds of long non-coding RNAs (lncRNAs) have been identified to have an important role in the biological function of CRC. However, the effect of lncRNA zinc finger antisense 1 (ZFAS1) on development of CRC is still incompletely clear.

Material/Methods

Firstly, the expression of ZFAS1 and microRNA (miR)-7-5p in 40 CRC tissues and adjacent tissues was measured by real-time polymerase chain reaction. Then, we detected the cell proliferation, migration, invasion, and apoptosis in CRC cell lines by using Cell Counting Kit-8 assay, colony formation assay, flow analysis, and Transwell assay, respectively. Then, the relationship between ZFAS1 and miR-7-5p was verified by luciferase reporter assay. Finally, rescue experiments were conducted to confirmed that interaction of ZFAS1 and miR-7-5p in vitro.

Results

Our results showed that ZFAS1 was upregulated in CRC tissues, correlated with overall survival rates, and negatively related to the expression of miR-7-5p. It was verified that miR-7-5p was a direct target of ZFAS1 by bioinformatics analysis and luciferase reporter assay. In addition, knockdown of miR-7-5p inhibited proliferation, migration, and invasion, and promoted apoptosis in CRC cell lines, which could be rescue by miR-7-5p inhibitor.

Conclusions

Our study indicated that ZFAS1 directly targeted miR-7-5p, and knockdown of it could inhibit tumor growth, migration, invasion, and induce apoptosis in CRC. These data might provide a potent treatment mechanism or promising biomarker for CRC.

The functions and oncogenic roles of CCAT1 in human cancer

In various human cancers, long non-coding RNAs (lncRNAs), a novel class of RNAs longer than 200 nucleotides without protein-coding potential, are implicated in a variety of biological processes, such as cell proliferation, invasion, metastasis, and apoptosis through regulation of gene expression at various levels including chromatin, splicing, transcriptional and post-transcriptional levels. However, the mechanisms underlying these are still elusive. Colon cancer-associated transcript 1(CCAT1) has received increased attention among those lncRNAs. Studies have shown high expression pattern and oncogenic role of CCAT1 in different types of cancer, and aberrant expression of CCAT1 has been involved in tumor-genesis, progression, metastasis, and patient survival via regulating different target genes and signaling pathways. In this review, we first introduce the concept, identification, and biological function of CCAT1; we then describe the mechanisms by which CCAT1 regulate the cancer proliferation and progression. In the last, we discuss emerging insights into the role of CCAT1 as potential biomarker and therapeutic target for novel treatment paradigms in cancer.

Red-emitting FIT-PNAs: "On site" detection of RNA biomarkers in fresh human cancer tissues

To date, there are limited approaches for the direct and rapid visualization (on site) of tumor tissues for pathological assessment and for aiding cytoreductive surgery. Herein, we have designed FIT-PNAs (forced-intercalation-peptide nucleic acids) to detect two RNA cancer biomarkers. Firstly, a lncRNA (long noncoding RNA) termed CCAT1, has been shown as an oncogenic lncRNA over-expressed in a variety of cancers. The latter, an mRNA termed KRT20, has been shown to be over-expressed in metastases originating from colorectal cancer (CRC). To these FIT-PNAs, we have introduced the bis-quinoline (BisQ) cyanine dye that emits light in the red region (605-610 nm) of the visible spectrum. Most strikingly, spraying fresh human tissue taken from patients during cytoreductive surgery for peritoneal metastasis of colon cancer with an aqueous solution of CCAT1 FIT-PNA results in bright fluorescence in a matter of minutes. In fresh healthy tissue (from bariatric surgeries), no appreciable fluorescence is detected. In addition, a non-targeted FIT-PNA shows no fluorescent signal after spraying this FIT-PNA on fresh tumor tissue emphasizing the specificity of these molecular sensors. This study is the first to show on-site direct and immediate visualization of an RNA cancer biomarker on fresh human cancer tissues by topical application (spraying) of a molecular sensor.

Downregulation of lncRNA CCAT1 enhances 5-fluorouracil sensitivity in human colon cancer cells

BACKGROUND

The purpose of this study was to determine the aberrant expression of the long noncoding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) in 5-fluorouracil-resistant colonic neoplasm cells and to elucidate its effects on the 5-fluorouracil sensitivity of human colonic neoplasm cells. The aberrant expression of lncRNAs in normal tissues and colonic neoplasm tissues was detected by microarray assay. qRT-PCR analysis was performed to assess CCAT1 expression levels in colonic neoplasm cell lines and corresponding normal tissues. After constructing the 5-FU-resistant cell lines and validating the resistance by measuring the IC₅₀ value, the CCAT1 expression levels in parental and artificially resistant cell lines were determined by qRT-PCR. Transfection was used to modulate the expression of CCAT1. Cell proliferation and apoptosis were then detected by CCK-8 and flow cytometry, respectively.

RESULTS

CCAT1 in colon cancer tissues was higher than that in noncancer tissues, and the levels of CCAT1 in HCT 116, SW1417, HT-29, and KM12 cell lines were higher than those in the human normal colon epithelial NCM460 cell line. Moreover, the expression levels of CCAT1 were high in HCT 116/5-FU and HT-29/5-FU cell lines, whose apoptosis rates induced by 5-FU were lower than those in corresponding parental cells. The results of qRT-PCR and CCK-8 assay showed that enhancement of lncRNA CCAT1 expression levels in HCT 116 and HT-29 cell lines increased their IC₅₀ of 5-FU and decreased their apoptosis rates. Meanwhile, siRNA-CCAT1 effectively inhibited the expression of CCAT1 and enhanced the 5-FU-sensitivity of HCT 116/5-FU and HT-29/5-FU, in which apoptosis rates were increased at the same time.

CONCLUSIONS

Downregulation of CCAT1 effectively reversed the resistance of HCT 116/5-FU and HT-29/5-FU cells to 5-FU chemotherapeutic, opening a new avenue in colon cancer therapy.

Long noncoding RNA RUSC1‑AS‑N promotes cell proliferation and metastasis through Wnt/β‑catenin signaling in human breast cancer

Breast cancer is one of the most frequently diagnosed cancers among females worldwide. Long noncoding RNAs (lncRNAs) have been revealed to serve significant roles in diagnosis and treatment of breast cancer. In the present study, the novel lncRNA RUSC1-AS-N was demonstrated to promote cell viability and metastasis. A total of 100 patients with breast cancer were recruited for this study and it was revealed that RUSC1-AS-N was upregulated in tumor tissues compared with in adjacent non-cancerous counterparts. In addition, using several breast cancer cell lines, it was demonstrated that the mRNA levels of RUSC1-AS-N were highest in the notably metastatic cell lines MDA-MB-231 and MDA-MB-468. Knockdown of RUSC1-AS-N in breast cancer cells inhibited cell proliferation in the colony formation and cell proliferation assays. Furthermore, depletion of RUSC1-AS-N suppressed cell metastasis, as revealed by wound-healing and western blot assays. In addition, the protein levels of Wnt1 and β-catenin were significantly decreased when RUSC1-AS-N was knocked down. However, Wnt signaling pathway activator Wnt agonist 1 reversed the effects of RUSC1-AS-N knockdown on cell proliferation and metastasis. The present study demonstrated that lncRNA RUSC1-AS-N promoted cell viability and metastasis via Wnt/β-catenin signaling in human breast cancer, which may indicate novel targets for the treatment of breast cancer in clinic.

The value of long noncoding RNA CASC2 as a biomarker of prognosis in carcinomas: a meta-analysis

Lnc RNA Cancer Susceptibility Candidate 2(CASC2) has been shown to be aberrantly expressed in multiple types of cancer and might serve as a prognosis biomarker. The present meta-analysis was conducted to investigate whether the expression of CASC2 was associated with prognosis or clinicopathological features in correlative cancers. A total of 11 studies with 765 cancer patients were included by searching the electronic databases, the results found a significant association between high expression of CASC2 and longer OS in cancer patients (HR=0.43, 95% CI: 0.33-0.55, P =0.000).In addition, a significant correlation was observed between high level of CASC2 and earlier TNM stage(OR = 0.30, 95% CI =0.21-0.43, P < 0.001), smaller tumor size(OR = 0.28, 95% CI =0.12-0.66, P =0.004), better tumor differentiation(OR = 0.42, 95% CI =0.27-0.66, P =0.0002). In conclusion, CASC2 can serve as a novel marker predicting the prognosis and clinicopathological features in various cancers.

A novel long noncoding RNA HOXC-AS3 mediates tumorigenesis of gastric cancer by binding to YBX1

BACKGROUND

Recently, increasing evidence shows that long noncoding RNAs (lncRNAs) play a significant role in human tumorigenesis. However, the function of lncRNAs in human gastric cancer remains largely unknown.

RESULTS

By using publicly available expression profiling data from gastric cancer and integrating bioinformatics analyses, we screen and identify a novel lncRNA, HOXC-AS3. HOXC-AS3 is significantly increased in gastric cancer tissues and is correlated with clinical outcomes of gastric cancer. In addition, HOXC-AS3 regulates cell proliferation and migration both in vitro and in vivo. RNA-seq analysis reveals that HOXC-AS3 knockdown preferentially affects genes that are linked to proliferation and migration. Mechanistically, we find that HOXC-AS3 is obviously activated by gain of H3K4me3 and H3K27ac, both in cells and in tissues. RNA pull-down mass spectrometry analysis identifies that YBX1 interacts with HOXC-AS3, and RNA-seq analysis finds a marked overlap in genes differentially expressed after YBX1 knockdown and those transcriptionally regulated by HOXC-AS3, suggesting that YBX1 participates in HOXC-AS3-mediated gene transcriptional regulation in the tumorigenesis of gastric cancer.

CONCLUSIONS

Together, our data demonstrate that abnormal histone modification-activated HOXC-AS3 may play important roles in gastric cancer oncogenesis and may serve as a target for gastric cancer diagnosis and therapy.

Long non-coding RNAs as emerging regulators of epithelial to mesenchymal transition in gynecologic cancers

Gynecologic cancer is a vital global healthcare issue with high rates of mortality and morbidity. Tumor metastasis attributes to most of the death suffering from solid tumors. The epithelial-mesenchymal transition (EMT) plays a pivotal role in initiating metastasis. Long non-coding RNAs (lncRNAs), a well-known group of non-coding RNAs, and a prominent topic in life science research, are misregulated in many malignancies and some are EMT-associated. In the case of gynecologic cancers, several EMT-associated lncRNAs have been identified and found to be implicated in cancer aggressiveness and progression. Mechanically, these lncRNAs participate in the EMT-related metastatic process in multiple ways including interaction with polycomb repressive complex 2 (PRC2), regulation of EMT signaling networks, mediation of EMT-transcription factors (EMT-TFs) and EMT markers, and cooperation with microRNAs (miRNAs). Further studies on these EMT-associated lncRNAs and identification of more relevant lncRNAs are imperative for the lncRNAs-based clinical management of high rate of metastasis in patients with gynecologic cancers.

Long non-coding RNA CCAT1 as a diagnostic and prognostic molecular marker in various cancers: a meta-analysis

PURPOSE

Long non-coding RNA colon cancer-associated transcript-1 (CCAT1) is newly found to be related with diagnoses and prognosis of cancer. This meta-analysis was performed to investigate the relationship between CCAT1 expression and clinical parameters, including survival condition, lymph node metastasis and tumor node metastasis grade.

MATERIALS AND METHODS

The primary literatures were collected through initial search criteria from electronic databases, including PubMed, OVID Evidence-based medicine Reviews and others (up to May 12, 2017). Eligible studies were identified and selected by the inclusion and exclusion criteria. Data was extracted and computed into Hazard ratio (HR) for the assessment of overall survival, subgroup analyses were prespecified based on the digestive tract cancer or others. Analysis of different CCAT1 expression related with lymph node metastasis or tumor node metastasis grade was conducted. Risk of bias was assessed by the Newcastle-Ottawa Scale.

RESULTS

9 studies were included. This meta-analysis showed that high CCAT1 expression level was related to poor overall survival, the pooled HR was 2.42 (95% confidence interval, CI: 1.86-3.16; P < 0.001; fix- effects model), similarly in the cancer type subgroups: digestive tract cancer (HR, 2.42; 95% CI, 1.79-3.29; P < 0.001; fix- effects model) and others (HR, 2.42; 95% CI, 1.42-4.13; P = 0.001; fix- effects model). The analysis showed that high CCAT1 was strongly related to positive lymph node metastasis (Odds ratio, OR: 3.24; 95% CI, 2.04-5.16; P < 0.001; fix- effects model), high tumor node metastasis stage (OR, 3.87; 95% CI, 2.53-5.92; P < 0.001; fix- effects model).

CONCLUSIONS

In conclusion, this meta-analysis revealed that CCAT1 had potential as a diagnostic and prognostic biomarker in various cancers.

Long Noncoding RNA GAPLINC Promotes Cells Migration and Invasion in Colorectal Cancer Cell by Regulating miR-34a/c-MET Signal Pathway

BACKGROUND

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) has been detected in colorectal cancer (CRC) cells and reportedly performs many functions related to tumor proliferation and metastasis. Aim The present study aimed to comprehensively explore the biological functions of GAPLINC and their underlying mechanism in CRC cell.

METHODS

The human cancer LncRNA PCR array was used to detect the differentially expressed long noncoding RNAs in human CRC samples. Real-time PCR, dual-luciferase assay, RNA pull-down assay, Transwell assay, and western blot analysis were performed to explore the molecular mechanism underlying GAPLINC functions related to migration and invasion of a human CRC cell line (HCT116).

RESULTS

Compared to the non-cancerous tissues, GAPLINC expression was obviously increased in CRC tissues. In HCT116, silencing of GAPLINC weakened cell migration and invasion, while overexpression of GAPLINC significantly promoted cell migration and invasion. Through dual-luciferase, RNA pull-down, and Transwell assays, we verified that miR-34a was the downstream molecule of GAPLINC and that miR-34a negatively regulated the migration and invasion of HCT116 cell. Furthermore, we found that GAPLINC positively regulated the miR-34a target gene c-MET in CRC tissues.

CONCLUSIONS

Our findings revealed that GAPLINC was up-regulated in CRC tissues and was involved in the migration and invasion of CRC cells by regulating miR-34a/c-MET signaling pathway.