Decreased Expression of miR-138-5p by lncRNA H19 in Cervical Cancer Promotes Tumor Proliferation

The Role of microRNAs, Long Non-coding RNAs, and Circular RNAs in Cervical Cancer

Prolonged infection of uterine cervix epithelium with human papillomavirus (HPV) and constitutive expression of viral oncogenes have been recognized as the main cause of the complex molecular changes leading to transformation of cervical epithelial cells. Deregulated expression of microRNAs (miRNA), long non-coding RNAs (lncRNA), and circular RNAs (circRNA) is involved in the initiation and promotion processes of cervical cancer development. Expression profiling of small RNAs in cervical neoplasia revealed up-regulated “oncogenic” miRNAs, such as miR-10a, miR-21, miR-19, and miR-146a, and down regulated “tumor suppressive” miRNAs, including miR-29a, miR-372, miR-214, and miR-218, associated with cell growth, malignant transformation, cell migration, and invasion. Also several lncRNAs, comprising among others HOTAIR, MALAT1, GAS5, and MEG3, have shown to be associated with various pathogenic processes such as tumor progression, invasion as well as therapeutic resistance and emerged as new diagnostic and prognostic biomarkers in cervical cancer. Moreover, human genes encoded circular RNAs, such as has_circ-0018289, have shown to sponge specific miRNAs and to concur to the deregulation of target genes. Viral encoded circE7 has also demonstrated to overexpress E7 oncoprotein thus contributing to cell transformation. In this review, we summarize current literature on the complex interplay between miRNAs, lncRNAs, and circRNAs and their role in cervical neoplasia.

Regulations of miR-183-5p and Snail-Mediated Shikonin-Reduced Epithelial-Mesenchymal Transition in Cervical Cancer Cells

Background

Shikonin, the main ingredient of Lithospermum erythrorhizon, has been reported to have antitumor effects via multiple targets and signaling pathways. However, the detailed mechanism underlying the effects in cervical cancer still remained unknown.

Methods

MTT, wound-healing, transwell assays and flow cytometry experiments were used to measure cell growth, migration, invasion, and cell cycle analysis. Western blot was used to examine protein levels of Snail, Vimentin and E-cadherin. The expression level of miR-183-5p was measured via qRT-PCR. The E-cadherin promoter activity was detected via Secrete-PairTM Dual Luminescence Assay Kit. The transient transfection experiments were used for silencing of E-cadherin and overexpression of Snail genes. Tumor xenograft and bioluminescent imaging experiments were carried out to confirm the in vitro findings.

Results

We showed that shikonin inhibited cell viability, migration and invasion, and induced cell cycle arrest in a dose-dependent manner in cervical cancer Hela and C33a cells. Mechanistically, we found that shikonin increased miR-183-5p expression and inhibited expression of transcription factor Snail protein. The mimics of miR-183-5p reduced, while the inhibitors of miR-183-5p reversed shikonin-inhibited Snail protein expression. In addition, shikonin decreased Vimentin, increased E-cadherin protein expressions and E-cadherin promoter activity, the latter was reversed in cells transfected with exogenous Snail overexpression vectors. Moreover, silencing of E-cadherin significantly abolished shikonin-inhibited cervical cancer cell growth. Similar findings were also observed in vivo using one xenograft mouse model.

Conclusion

Our results show that shikonin inhibits EMT through inhibition of Snail and stimulation of miR-183-5p expressions, which resulted in induction of E-cadherin expression. Thus, blockade of EMT could be a novel mechanism underlying the anti-cervical cancer effects of shikonin.

Investigation of the Association of miRNA-499, miRNA-146a, miRNA-196a2 Loci with Hepatocellular Carcinoma Risk: A Case-Control Study Involving 1507 Subjects

microRNAs' (miRNAs) loci may influence hepatocellular carcinoma (HCC) development. Many recent studies have assessed the relationship between miRNA-499, miRNA-146a, and miRNA-196a2 loci and HCC risk. However, the observed results are conflicting. A total of 584 HCC patients and 923 age- and sex-matched controls were recruited. The correlation of miRNA-499 rs3746444, miRNA-146a rs2910164, and miRNA-196a2 rs11614913 with HCC development was assessed. In the <53-year-old subgroup, a correlation of the rs2910164 locus with HCC risk was found (GG/CG vs. CC: adjusted p = 0.011, GG vs. CC: adjusted p = 0.021 and CG vs. CC: adjusted p = 0.027). The association between miRNA-146a rs2910164 and the risk of HCC was also found in the never smoking (GG/CG vs. CC: adjusted p = 0.011 and CG vs. CC: adjusted p = 0.018). Using false-positive report probability method and power value, we identified that miRNA-146a rs2910164 conferred a risk to HCC in the <53-year-old and never-smoking subgroups. In conclusion, this study indicates rs2910164 may be a risk factor for HCC, especially in the <53-year-old and never-smoking subgroups.

A novel, noncoding-RNA-mediated, post-transcriptional mechanism of anti-Mullerian hormone regulation by the H19/let-7 axis

In reproductive age women, the pool of primordial follicles is continuously depleted through the process of cyclic recruitment. Anti-Mullerian hormone (AMH) both inhibits the initial recruitment of primordial follicles into the growing pool and modulates the sensitivity of growing follicles to follicle stimulating hormone. Thus, AMH may be an important modulator of female infertility and ovarian reserve; however, the mechanisms regulating AMH remain unclear.To evaluate AMH levels in the absence of H19 lncRNA, H19 knockout (H19KO) mice were evaluated for analysis of ovarian AMH gene expression, protein production, and reproductive function, including assessment of follicle numbers and litter size analysis. To further investigate regulation of AMH by the H19/let-7 axis, let-7 binding sites on AMH were predicted, and in vitro studies of the effect of H19 knockdown/overexpression with let-7 rescue were performed. Lastly, response to superovulation was assessed via oocyte counts and estradiol measurements.The H19KO mouse demonstrates subfertility and accelerated follicular recruitment with increased spontaneous development of secondary, preantral, and antral follicles. Ovaries of H19KO mice have decreased AMH mRNA and protein, and AMH mRNA has a functional let-7 binding site, suggesting a plausible ncRNA-mediated mechanism for AMH regulation by H19/let-7. Lastly, in the absence of H19, superovulation results in higher estradiol and more oocytes, suggesting that H19 functions to limit the number of follicles that mature, produce estradiol, and ovulate. Thus, AMH's inhibitory actions are regulated at least in part by H19, likely via let-7, marking this ncRNA pair as important regulators of the establishment and maintenance of the follicular pool.

The prognostic value of long non-coding RNA H19 in various cancers: A meta-analysis based on 15 studies with 1584 patients and the Cancer Genome Atlas data

BACKGROUND

Recent studies have shown that long noncoding RNA (lncRNA) H19 is aberrantly expressed in various cancers. However, the prognostic significance of H19 in cancer patients remains to be elucidated. Here, we designed and conducted a meta-analysis to evaluate the prognostic value of this lncRNA for malignant solid neoplasms.

METHODS

Relevant publications were collected from PubMed, Cochrane Library, Web of Science, and Embase databases. The relevant survival data of patients with H19-associated cancers were downloaded from The Cancer Genome Atlas (TCGA) project. Statistically significant relationships between H19 expression levels and overall survival were analyzed by hazard ratios (HRs) and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 15 studies with 1584 patients were ultimately included for this literature meta-analysis. An elevated level of H19 expression was found to be negatively correlated with the overall survival (OS) (HR = 1.62, 95% CI = 1.36-1.93, P < .001) in various cancers. Abnormal H19 expression was also positively correlated with poor tumor differentiation (P < .0001), more advanced clinical stage (P < .0001), earlier lymph node metastasis (P < .0001), and earlier distant metastasis (P < .05). The relationship between elevated H19 expression and overall survival was further validated by a TCGA dataset consisting of 7462 cancer patients (HR = 1.12, 95% CI = 1.03-1.22, P < .05).

CONCLUSION

Our study indicates that H19 expression is closely relevant to clinical outcome and suggests that lncRNA H19 could be a crucial prognostic biomarker for certain carcinoma types.

Co-expression analysis and ceRNA network reveal eight novel potential lncRNA biomarkers in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary liver cancer in the world, with a high degree of malignancy and recurrence. The influence of the ceRNA network in tumor on the biological function of liver cancer is very important, It has been reported that many lncRNA play a key role in liver cancer development. In our study, integrated data analysis revealed potential eight novel lncRNA biomarkers in hepatocellular carcinoma.

METHODS

Transcriptome data and clinical data were downloaded from the The Cancer Genome Atlas (TCGA) data portal. Weighted gene co-expression network analysis was performed to identify the expression pattern of genes in liver cancer. Then, the ceRNA network was constructed using transcriptome data.

RESULTS

The integrated analysis of miRNA and RNAseq in the database show eight novel lncRNAs that may be involved in important biological pathways, including TNM and disease development in liver cancer. We performed function enrichment analysis of mRNAs affected by these lncRNAs.

CONCLUSIONS

By identifying the ceRNA network and the lncRNAs that affect liver cancer, we showed that eight novel lncRNAs play an important role in the development and progress of liver cancer.

The long non-coding RNA H19: an active player with multiple facets to sustain the hallmarks of cancer

Cancer cells exhibit hallmarks in terms of proliferation, resistance to cell death, angiogenesis, invasion, metastasis, and genomic instability. Despite the progress in cancer research and the comprehension of tumorigenesis mechanisms, cancer remains a major issue in public health. A better understanding of the molecular factors associated with the appearance or progression of cancer may allow the development of therapeutic alternatives. Increasing data highlight the role of long non-coding RNAs in many diseases, including cancer. The long non-coding RNA H19 was the first discovered riboregulator, and it has been shown to be involved at multiple steps of tumorigenesis. Indeed, this lncRNA exert its action at various molecular scales. Understanding the role of H19 in cancer progression may allow to set up therapeutic strategies to prevent tumor expansion and metastatic dissemination. In this review, we will summarize the overexpression of the long non-coding RNA H19 in several types of cancer and the multiple implications of the long non-coding RNA H19 in the different hallmarks that define human cancer.

lncRNA PDIA3P regulates cell proliferation and invasion in non-small cell lung cancer

Increasing evidence has shown that long non-coding RNAs (lncRNAs) serve a critical role in tumor progression. The lncRNA protein disulfide isomerase family A member 3 pseudogene 1 (PDIA3P) is associated with the progression of oral squamous cell carcinoma and multiple myeloma. However, the roles of lncRNA PDIA3P in non-small cell lung cancer (NSCLC) remain unknown. In the present study, it was demonstrated that lncRNA PDIAP3 expression was significantly increased in patients with NSCLC, particularly in patients with an advanced Tumor-Node-Metastasis stages and lymph-node metastasis. The Gene Expression Profiling Interactive Analysis database revealed that patients with NSCLC with high lncRNA PDIA3P expression had a poorer disease-free survival rate. Furthermore, functional assays suggested that PDIA3P inhibition significantly suppressed the proliferation and invasion of NSCLC cells in vitro and reduced tumor growth in vivo. In addition, lncRNA PDIA3P enhanced the activity of the Wnt/β-catenin pathway in progression of NSCLC. The present study showed that lncRNA PDIA3P promoted NSCLC progression by regulating Wnt/β-catenin signaling, highlighting a potential therapeutic target for treating patients with NSCLC treatment.

Association of miRNA-499 rs3746444 A>G variants with adenocarcinoma of esophagogastric junction (AEG) risk and lymph node status

Background

MicroRNAs (miRNAs) miRNA-499 rs3746444 A>G polymorphism may be complicated in the susceptibility to cancer. However, the correlation of this polymorphism with adenocarcinoma of esophagogastric junction (AEG) was unknown.

Patients and methods

A total of 1063 AEG patients and 1677 controls were included in this study to assess the association of miR-499 rs3746444 A>G with AEG risk. SNPscan^TM genotyping assay was harnessed to obtain the genotypes of miRNA-499 rs3746444 A>G polymorphism.

Results

We identified that SNP miR-499 rs3746444 A>G increased the susceptibility of AEG (AG vs AA: adjusted OR=1.25, 95% CI=1.05–1.49, P=0.012 and AG/GG vs AA: adjusted OR=1.30, 95% CI=1.10–1.54, P=0.002). In a stratified analysis, we found that miR-499 rs3746444 A>G polymorphism had an increased susceptibility of AEG in several subgroups (male subgroup: AG vs AA: adjusted P=0.004 and AG/GG vs AA: adjusted P=0.002; female subgroup: GG vs AG/AA: adjusted P=0.046; <64 years subgroup: AG vs AA: adjusted P=0.006 and AG/GG vs AA: adjusted P=0.003; never smoking subgroup: AG vs AA: adjusted P=0.003 and AG/GG vs AA: adjusted P=0.001; and never drinking subgroup: AG vs AA: adjusted P=0.008 and AG/GG vs AA: adjusted P=0.002). The results of power calculation indicated that miR-499 rs3746444 A>G polymorphism increased the risk of AEG in overall comparison, male, <64 years, never smoking, and never drinking subgroups. Among the AEG cases, 625 patients accompanied by positive lymph node. However, the distribution of miRNA-499 rs3746444 A>G variants was no significant difference between different lymph node status.

Conclusion

Our findings indicate that miR-499 rs3746444 A>G polymorphism is significantly associated with AEG susceptibility. In the future, further exploration of this genetic factor in relation to AEG susceptibility with an adequate methodological quality is needed.

Deregulation of H19 is associated with cervical carcinoma

CACX is one of the most common cancer affecting women world-wide. Here, expression microarray analysis revealed 8 over-expressed transcribed pseudogenes (GBP1P1, HLA-DRB6, HLA-H, SLC6A10P, NAPSB, KRT16P2, PTTG3P and RNF126P1), down-regulated 7 lincRNAs (H19, MIR100HG, MEG3, DIO3OS, HOXA11-AS, CD27-AS1 and EPB41L4A-AS) and 6 snoRNAs (SNORD97, SNORD3A, SNORD3C, SNORD3D, SNORA12 and SCARNA9) as DEncGs (log2 fold-change ≥ ±1.0) in CACX. Consequently, down-regulation of lincRNA MEG3 and over-expression of pseudogenes, GBP1P1 and PTTG3P in the microarray analysis were found concordant with the real-time quantitative PCR results upon validation. Then, Ingenuity® Pathway analysis (IPA®) analysis with deregulated DEncGs identified functionally important gene, H19. Further, validation (n = 52) of expression confirmed frequent downregulation of H19 with significant association with its deletion (LOH) and promoter methylation (n = 128) in CACX. Moreover, clinicopathological analysis found Indian CACX patients (n = 26) with alterations of H19 by deletion or, promoter methylation with concomitant low expression have poor prognosis.

Pivotal role of microRNA-138 in human cancers

Aberrant expression of certain microRNAs (miRNAs) has been implicated in cancers as a promising druggable target due to the fact that a modulation of the deregulated single miRNA seems to revert the therapeutically unfavorable gene expressions in cancer cell by targeting multiple genes. Global miRNA profiling from a number of patient cohorts in various type of human cancers has identified miR-138 as a signature of tumor suppressor that are down-regulated in most types of human cancer. As a tumor suppressor, miR-138 can inhibit oncogenic proteins by directly bind to their mRNAs. However, in rare cases of cancer stem cell population from glioblastoma, miR-138 seems to be down-regulated and plays an oncogenic function. This review will summarize accumulating evidence that has shown the expression and functional role of miR-138 in various human cancers with its target genes and pathways in a hope to find a better therapeutic option to treat human cancers.

Silencing of long noncoding RNA RP11-476D10.1 enhances apoptosis and autophagy while inhibiting proliferation of papillary thyroid carcinoma cells via microRNA-138-5p-dependent inhibition of LRRK2

The distant metastasis in papillary thyroid carcinoma (PTC) is a major threat for PTC patients. Moreover, the involvement of long noncoding RNAs (lncRNAs) in the regulation of PTC progression has been extensively investigated. The aim of this study was to underscore whether lncRNA RP11-476D10.1 affects the proliferation, apoptosis and autophagy of PTC cells. Initially, we determined that lncRNA RP11-476D10.1 and LRRK2 were highly expressed in PTC cells. Meanwhile, through experimentation, miR-138-5p was confirmed to bind with lncRNA RP11-476D10.1 and LRRK2. It was also revealed that lncRNA RP11-476D10.1 downregulated the miR-138-5p expression, thereby upregulating the LRRK2 expression. After that, PTC cells were transfected with siRNA against RP11-476D10.1, or inhibitor or mimic of miR-138-5p to evaluate the influence of lncRNA RP11-476D10.1 on the PTC cell proliferation, apoptosis, and autophagy in vitro and on the tumor formation ability in vivo. The results showed that silenced lncRNA RP11-476D10.1 or overexpressed miR-138-5p enhanced the apoptosis and autophagy of PTC cells while reducing cell proliferation, with increased levels of Bax, LC3B, and Beclin1 and decreased Bcl-2 level were observed. The inhibitory role of silenced lncRNA RP11-476D10.1 role in the PTC development was further verified by the reduced tumor formation ability in nude mice. Our results demonstrated that lncRNA RP11-476D10.1 could bind to miR-138-5p and promote LRRK2 expression. Moreover, the silencing of lncRNA RP11-476D10.1 may inhibit the development of PTC, highlighting a novel insight for the development of superior therapeutic targets for PTC treatment.

Long non-coding RNA H19 regulates cell growth and metastasis via miR-138 in breast cancer

Breast cancer is one of the most common cancers among women. Long non-coding RNAs (lncRNAs) are involved in the initiation and development of breast cancer and lncRNA H19 is a potential oncogenic factor; however, the underlying mechanisms remain unknown. In the present study, the regulatory functions of H19 in breast cancer were investigated. We found that H19 was upregulated in breast cancer tissues and cells and associated with poor prognosis. MiR-138 was downregulated in breast cancer tissues and negatively correlated with the expression of H19 and SOX4. Furthermore, SOX4 was upregulated in breast cancer tissues and positively correlated with H19. Downregulated H19 suppressed the proliferation, invasion and migration of breast cancer cells, but promoted cell cycle arrest and apoptosis. Additionally, miR-138 was identified as a direct target of H19 and SOX4; overexpression of miR-138 inhibited the proliferation, invasion and migration of MDA-MB-231 and MCF-7 cells, but promoted apoptosis, which were abrogated by SOX4 overexpression. Downregulated miR-138 induced cell proliferation, invasion and migration, but inhibited apoptosis of MDA-MB-231 and MCF-7 cells, which were promoted by SOX4 overexpression. In addition, miR-138 overexpression reversed the effects of H19 in breast cancer cells; silencing of H19 inhibited tumor growth and downregulate EMT markers in vivo. In summary, H19 was upregulated in breast cancer and associated with poor prognosis. Silencing of H19 inhibited cell proliferation, invasion and migration, but induced cell cycle arrest and apoptosis by regulating miR-138 and SOX4 in breast cancer.

Expression of the lncRNA ZFAS1 in cervical cancer and its correlation with prognosis and chemosensitivity

OBJECTIVE

To investigate the expression of the lncRNA ZFAS1 in cervical cancer and its relationship with patient prognosis and cervical cancer cell chemosensitivity.

METHODS

The expression of ZFAS1 in cervical cancer tissues and cell lines was detected by qRT-PCR. The cervical cancer CaSki and the HeLa cell lines were transfected to be divided into Blank, siR-Control, and siR-ZFAS1 groups. MTT, wound-healing, and transwell assays were used to evaluate cell biological function. Cisplatin with different concentrations was used to treat cells in different transfection groups, and MTT assays were used to detect the cell growth inhibition rate and the half-inhibitory concentration (IC50) of cisplatin was measured. Cell apoptosis was determined by flow cytometry. A xenograft mouse model was used to investigate the effects of siR-ZFAS1 on the chemosensitivity to cisplatin.

RESULTS

ZFAS1 was significantly upregulated in cervical cancer tissues and cell lines, and increased ZFAS1 levels led to poor prognoses in patients. In addition, cells in the siR-ZFAS1 group showed remarkably reduced ZFAS1 expression as well as cell proliferation, invasion and migration. After being treated with cisplatin at different concentrations, cells in the siR-ZFAS1 group had dramatically increased cell growth inhibition and apoptosis but lower cisplatin IC50s. In addition, siR-ZFAS1 reduced the volumes and weights of tumors in nude mice treated with cisplatin and enhanced the chemosensitivity of cervical cancer cells to cisplatin.

CONCLUSION

The lncRNA ZFAS1 was upregulated in cervical cancer tissues, and its high expression indicated a poor prognosis. Silencing ZFAS1 may inhibit cell proliferation, migration and invasion and enhance cisplatin chemosensitivity.

Involvement of H19/miR-326 axis in hepatocellular carcinoma development through modulating TWIST1

Overexpression of long noncoding RNA (lncRNA) H19 has been observed in various cancers, which indicates that H19 exert important roles in the progression of carcinogenesis. MiR-326 has been reported to play tumor suppressive roles in multiple tumors. Recently, the competing endogenous RNA (ceRNA) hypothesis has implied that lncRNAs might function as molecular sponges for microRNAs in various cancers. However, the roles of H19/miR-326 in human hepatocellular carcinoma (HCC) still remain unclear. The aim of our study was to determine H19/miR-326 expression in HCC cells and investigate their roles in HCC development. We found that H19 was significantly elevated and miR-326 was decreased in HCC cells including Hep3B, HepG2, MHCC-97L, SK-hep1, Hun7, SMCC-7721 compared with LO2 cells, respectively. In the subsequent experiments, we observed that inhibition of H19 can repress HCC cell growth, migration, and invasion in vitro. H19 downregulation can increase miR-326 expression in HCC cells. Meanwhile, miR-326 mimics can also inhibit HCC progression, whereas miR-326 inhibitors exhibited a reverse phenomenon by modulating H19 expression. In addition, a negative association between H19 and miR-326 was predicted and confirmed. Furthermore, the transcription factor TWIST1 has been recognized as a significant regulator in tumor progression. Here, by performing bioinformatics analysis, TWIST1 was identified as a downstream target of miR-326. The findings of our study implied that lncRNA H19 can serve as a ceRNA to sponge miR-326 and modulate TWIST1 levels in HCC pathogenesis. Taken these together, these findings indicated that H19/miR-326/TWIST1 axis was involved in HCC development and can indicate a novel HCC target.

Identification of down-regulated microRNAs in thyroid cancer and their potential functions

BACKGROUND

The mechanism of microRNAs (miRNAs) in thyroid cancer is still unclear. We identified miRNAs with differential expression in thyroid cancer versus normal tissues.

METHODS

Microarray datasets were obtained from the GEO and ArrayExpress databases, and from publications found via PubMed, EMBASE, and Web of Science. Differentially expressed miRNAs were identified using the limma package, and their targets predicted using miRWalk. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) network analyses were performed using these target genes to explore potential carcinogenic mechanisms. Correlations between target gene and miRNA expression levels were examined. Changes in target protein expression were confirmed using data from The Human Protein Atlas and the Cancer Genome Atlas.

RESULTS

We ultimately included five datasets, and further analyzed the four miRNAs that were down-regulated in at least four datasets (miR-7-2-3p, miR-138-5p, miR-144-5p, miR-486-5p). Predicted targets were enriched in GO terms including extracellular matrix organization, cell surface, and receptor binding, and in KEGG cancer pathways. PPI analysis identified 10 hub genes as key potential targets of these miRNAs. The expression levels of eight target genes were negatively correlated with those of their respective miRNAs. Furthermore, eight predicted target genes in cancer-related pathways showed up-regulated protein and mRNA expression in thyroid cancer.

CONCLUSION

Low miRNA expression in thyroid cancer might influence tumorigenesis via critical pathways. The genes identified here may act as a starting point for further investigation of the carcinogenic mechanisms of these miRNAs.

Overexpression of microRNA-936 suppresses non-small cell lung cancer cell proliferation and invasion via targeting E2F2

MicroRNA (miR)-936 has been reported to inhibit the cell cycle and glioma cell proliferation. However, the roles of miR-936 in other human tumors remain largely unknown. In the present study, it was indicated that miR-936 was significantly downregulated in non-small cell lung cancer (NSCLC) tissues compared with adjacent normal tissues by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Results also indicated that miR-936 was downregulated in NSCLC cell lines compared with 16HBE cells. Furthermore, it was demonstrated that overexpression of miR-936 significantly inhibited the proliferation, cell cycle progression and invasion of NSCLC cells. Notably, E2F2 was identified as a target gene of miR-936 in NSCLC cells. The results indicated that E2F2 was upregulated in NSCLC tissues and cell lines, and its expression was negatively correlated with that of miR-936 in NSCLC tissues. Overexpression of miR-936 significantly reduced the protein expression levels of E2F2 in NSCLC cells. Furthermore, restoration of E2F2 rescued the proliferation and invasion of NSCLC cells transfected with miR-936 mimics. To the best of our knowledge, the present findings demonstrated for the first time that miR-936 suppressed NSCLC progression by directly targeting E2F2.

Long non-coding RNA CASC2 inhibits tumorigenesis via the miR-181a/PLXNC1 axis in melanoma

Melanoma is the most malignant and aggressive form of skin carcinoma originating in the pigment-producing melanocytes. In this study, to further investigate the molecular mechanisms of the development and progression of melanoma, we explored the impacts of long non-coding RNA (lncRNA) CASC2 on melanoma cell functions. Microarray analysis was carried out to identify the expression of lncRNA CASC2 in melanoma cells. MiR-181a was predicted as a sponging target of CASC2 by miRcode, while the 3'-UTR of Plexin C1 (PLXNC1) was a potential target of miR-181a according to the TargetScan database. The correlation among CASC2, miR-181a, and PLXNC1 was verified by dual luciferase reporter assay and qRT-PCR. After manipulation of CASC2, miR-181a and PLXNC1 expression with transfection in A375 and M14 cells, cell viability, apoptosis, and invasive ability were evaluated using CCK-8, flow cytometry and Transwell assays, respectively. A low expression of CASC2 was detected in melanoma tissues and cells. Dual luciferase reporting assay confirmed that miR-181a targeted the 3'-UTR of PLXNC1. Furthermore, CASC2 could efficiently sponge miR-181a, thereby facilitating the expression of PLXNC1. Up-regulation of CASC2 suppressed the cell proliferation and invasion, but induced the apoptosis of melanoma cells. Our results demonstrated that lncRNA CASC2 can promote PLXNC1 expression by sponging miR-181a, thereby inhibiting the proliferation and invasion of melanoma cells, indicating that lncRNA CASC2 functions via the miR-181a/PLXNC1 axis in melanoma.