The lncRNA RHPN1-AS1 downregulation promotes gefitinib resistance by targeting miR-299-3p/TNFSF12 pathway in NSCLC

The regulatory role and therapeutic potential of long non-coding RNA in non-small cell lung cancer

Lung cancer remains the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) being the predominant subtype. Recent advances in transcriptome sequencing have highlighted the critical role of long non-coding RNAs (lncRNAs) in NSCLC, with lncRNAs influencing gene expression through epigenetic, transcriptional, and post-transcriptional mechanisms. Despite the growing understanding of lncRNAs, challenges such as delayed diagnosis and drug resistance continue to complicate NSCLC management. This review explores novel findings in the role of lncRNAs (e.g., MALAT1, HOTAIR, and GAS5) in NSCLC, with a particular focus on their encoded small peptides and N6-methyladenosine (m6A) modifications. We further discuss how the interplay between lncRNAs, their encoded peptides, and m6A modifications can provide new strategies for improving NSCLC diagnosis, treatment, and overcoming drug resistance. This review also highlights emerging research avenues that could lead to innovative clinical interventions in NSCLC.

Emerging role of competing endogenous RNA in lung cancer drug resistance

Lung cancer remains one of the most common malignant cancers worldwide, and its survival rate is extremely low. Chemotherapy, the mainstay of lung cancer treatment, is not as effective as it could be due to the development of cellular resistance. The molecular mechanisms of drug resistance in lung cancer remain to be elucidated. Accumulating evidence suggests that ceRNAs are involved in various carcinogenesis and development. CeRNA is a transcript that regulates each other through competition with miRNA. However, the relationship between ceRNAs and chemoresistance in lung cancer remains unclear. In this narrative review, we provided a summary of treatment approaches that focus on ceRNA networks to overcome drug resistance.

Downregulation of lncRNA MIR17HG reduced tumorigenicity and Treg-mediated immune escape of non-small-cell lung cancer cells through targeting the miR-17-5p/RUNX3 axis

Long noncoding RNA MIR17HG was involved with the progression of non-small-cell lung cancer (NSCLC), but specific mechanisms of MIR17HG-mediated immune escape of NSCLC cells were still unknown. The present study investigated the function of MIR17HG on regulatory T cell (Treg)-mediated immune escape and the underlying mechanisms in NSCLC. Expression of MIR17HG and miR-17-5p in NSCLC tissue samples were detected using quantitative real-time PCR (qRT-PCR). A549 and H1299 cells were transfected with sh-MIR17HG, miR-17-5p inhibitor, or sh-MIR17HG + miR-17-5p inhibitor, followed by cocultured with Tregs. Cell proliferation was measured using 5-ethynyl-20-deoxyuridine (Edu) staining assay and cell counting kit-8 (CCK-8) assay. Flow cytometry was used for determining positive numbers of FOXP3+CD4+/CD25+/CD8+ Tregs. Through subcutaneous injection with transfected A549 cells, a xenograft nude mouse model was established. Weights and volumes of xenograft tumors were evaluated. Additionally, the expressions of immune-related factors including transforming growth factor beta (TGF-β), vascular endothelial growth factor A (VEGF-A), interleukin-10 (IL-10), IL-4, and interferon-gamma (IFN-γ) in cultured cells, were evaluated by enzyme-linked immunosorbent assay and western blot analysis. Then, miR-17-5p was decreased and MIR17HG was enhanced in both NSCLC tissues and cell lines. MIR17HG knockdown significantly suppressed cell proliferation, tumorigenicity, and immune capacity of Tregs in A549 and H1299 cells, whereas sh-MIR17HG significantly reduced expression levels of VEGF-A, TGF-β, IL-4, and IL-10 but promoted the IFN-γ level in vitro and in vivo. Moreover, downregulation of miR-17-5p significantly reversed the effects of sh-MIR17HG. Additionally, we identified that runt- related transcription factor 3 (RUNX3) was a target of miR-17-5p, and sh-MIR17HG and miR-17-5p mimics downregulated RUNX3 expression. In conclusion, downregulation of MIR17HG suppresses tumorigenicity and Treg-mediated immune escape in NSCLC through downregulating the miR-17-5p/RUNX3 axis, indicating that this axis contains potential biomarkers for NSCLC.

Long non-coding RNA and Evolving drug resistance in lung cancer

Non-small cell lung cancer (NSCLC) is one of the most devastating cancers with a high incidence and mortality rates of all cancers. Locally advanced or metastatic NSCLC patients can benefit from platinum-based chemotherapy and targeted therapy drugs. Nevertheless, primary or acquired drug resistance will result in ineffective treatment, leading to tumor progression. The detailed mechanism underlying drug resistance to NSCLC are complicated and result from various factor. Among them, long noncoding RNAs (lncRNAs) have been found to be critically involved in NSCLC development and play a vital role in mediating therapy resistance. In this review, we attempt to systematically summarize the mechanisms underlying the lncRNA-mediated resistance to chemotherapy agents and targeted therapy drugs against lung cancer.

Retracted: Long noncoding RNA RHPN1-AS1, induced by KDM5B, is involved in breast cancer via sponging miR-6884-5p

The above article, published online in Journal of Cellular Biochemistry on 31 January 2020 in Wiley Online Library (https://doi.org/10.1002/jcb.29645), has been retracted by agreement between the authors, the journal's Editor in Chief, Prof. Dr. Christian Behl, and Wiley Periodicals LLC. The authors asked to retract their article after substantial mistakes in experimental data were found, thus the results are considered to be invalid.

Comprehensive analysis of a novel cuproptosis-related lncRNA signature associated with prognosis and tumor matrix features to predict immunotherapy in soft tissue carcinoma

Background: A crucial part of the malignant processes of soft tissue sarcoma (STS) is played by cuproptosis and lncRNAs. However, the connection between cuproptosis-related lncRNAs (CRLs) and STS is nevertheless unclear. As a result, our objective was to look into the immunological activity, clinical significance, and predictive accuracy of CRLs in STS. Methods: The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, respectively, provided information on the expression patterns of STS patients and the general population. Cuproptosis-related lncRNA signature (CRLncSig) construction involved the univariate, multivariate, and least absolute shrinkage and selection operator Cox regression analysis. The predictive performance of the CRLncSig was evaluated using a serial analysis. Further research was done on the connections between the CRLncSig and the tumor immune milieu, somatic mutation, immunotherapy response, and chemotherapeutic drug susceptibility. Notably, an in vitro investigation served to finally validate the expression of the hallmark CRLs. Results: A novel efficient CRLncSig composed of seven CRLs was successfully constructed. Additionally, the low-CRLncSig group's prognosis was better than that of the high-CRLncSig group's based on the new CRLncSig. The innovative CRLncSig then demonstrated outstanding, consistent, and independent prognostic and predictive usefulness for patients with STS, according to the evaluation and validation data. The low-CRLncSig group's patients also displayed improved immunoreactivity phenotype, increased immune infiltration abundance and checkpoint expression, and superior immunotherapy response, whereas those in the high-CRLncSig group with worse immune status, increased tumor stemness, and higher collagen levels in the extracellular matrix. Additionally, there is a noticeable disparity in the sensitivity of widely used anti-cancer drugs amongst various populations. What's more, the nomogram constructed based on CRLncSig and clinical characteristics of patients also showed good predictive ability. Importantly, Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR) demonstrated that the signature CRLs exhibited a significantly differential expression level in STS cell lines. Conclusion: In summary, this study revealed the novel CRLncSig could be used as a promising predictor for prognosis prediction, immune activity, tumor immune microenvironment, immune response, and chemotherapeutic drug susceptibility in patients with STS. This may provide an important direction for the clinical decision-making and personalized therapy of STS.

Long non-coding RNA OGFRP1 regulates cell proliferation and ferroptosis by miR-299-3p/SLC38A1 axis in lung cancer

Lung cancer is devastating cancer that ranks as the leading cause of cancer-related death. Long noncoding RNA (lncRNA) opioid growth factor receptor pseudogene 1 (OGFRP1) was recognized as an oncogene in many cancers. However, the molecular mechanism of OGFRP1 in lung cancer is still poorly understood. The expression of target RNAs and genes was detected by quantitative real-time PCR and western blot. The interaction between miR-299-3p and OGFRP1 or solute carrier family 38 member 1 (SLC38A1) was predicted by StarbaseV3.0 and verified by dual-luciferase reporter assay and Pearson's correlation coefficient. Besides, a transplantation model of human lung cancer in nude mice was established to evaluate the role of OGFRP1 in lung cancer. OGFRP1 and SLC38A1 were overexpressed, whereas miR-299-3p was lowly expressed in lung cancer tumors and cells. OGFRP1 knockdown suppressed cell proliferation and facilitated ferroptosis by promoting lipid peroxidation and iron accumulation in lung cancer. Besides, Furthermore, miR-299-3p inhibitor or SLC38A1 overexpression attenuated OGFRP1 depletion-induced suppression on cell proliferation and ferroptosis in lung cancer. Animal experiments indicated that OGFRP1 deficiency restrained tumor growth in vivo by regulating the miR-299-3p/SLC38A1 axis. OGFRP1 regulated cell proliferation and ferroptosis in lung cancer by inhibiting miR-299-3p to enhance SLC38A1 expression, providing a novel therapeutic strategy for lung cancer.

Emerging Role of Noncoding RNAs in EGFR TKI-Resistant Lung Cancer

Lung cancer accounts for the majority of malignancy-related mortalities worldwide. The introduction of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) has revolutionized the treatment and significantly improved the overall survival (OS) of lung cancer. Nevertheless, almost all EGFR-mutant patients invariably acquire TKI resistance. Accumulating evidence has indicated that noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), have a central role in the tumorigenesis and progression of lung cancer by regulating crucial signaling pathways, providing a new approach for exploring the underlying mechanisms of EGFR-TKI resistance. Therefore, this review comprehensively describes the dysregulation of ncRNAs in EGFR TKI-resistant lung cancer and its underlying mechanisms. We also underscore the clinical application of ncRNAs as prognostic, predictive and therapeutic biomarkers for EGFR TKI-resistant lung cancer. Furthermore, the barriers that need to be overcome to translate the basic findings of ncRNAs into clinical practice are discussed.

Non-coding RNA in cancer drug resistance: Underlying mechanisms and clinical applications

Cancer is one of the most frequently diagnosed malignant diseases worldwide, posing a serious, long-term threat to patients’ health and life. Systemic chemotherapy remains the first-line therapeutic approach for recurrent or metastatic cancer patients after surgery, with the potential to effectively extend patient survival. However, the development of drug resistance seriously limits the clinical efficiency of chemotherapy and ultimately results in treatment failure and patient death. A large number of studies have shown that non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, are widely involved in the regulation of cancer drug resistance. Their dysregulation contributes to the development of cancer drug resistance by modulating the expression of specific target genes involved in cellular apoptosis, autophagy, drug efflux, epithelial-to-mesenchymal transition (EMT), and cancer stem cells (CSCs). Moreover, some ncRNAs also possess great potential as efficient, specific biomarkers in diagnosis and prognosis as well as therapeutic targets in cancer patients. In this review, we summarize the recent findings on the emerging role and underlying mechanisms of ncRNAs involved in cancer drug resistance and focus on their clinical applications as biomarkers and therapeutic targets in cancer treatment. This information will be of great benefit to early diagnosis and prognostic assessments of cancer as well as the development of ncRNA-based therapeutic strategies for cancer patients.

MicroRNAs as the critical regulators of tyrosine kinase inhibitors resistance in lung tumor cells

Lung cancer is the second most common and the leading cause of cancer related deaths globally. Tyrosine Kinase Inhibitors (TKIs) are among the common therapeutic strategies in lung cancer patients, however the treatment process fails in a wide range of patients due to TKIs resistance. Given that the use of anti-cancer drugs can always have side effects on normal tissues, predicting the TKI responses can provide an efficient therapeutic strategy. Therefore, it is required to clarify the molecular mechanisms of TKIs resistance in lung cancer patients. MicroRNAs (miRNAs) are involved in regulation of various pathophysiological cellular processes. In the present review, we discussed the miRNAs that have been associated with TKIs responses in lung cancer. MiRNAs mainly exert their role on TKIs response through regulation of Tyrosine Kinase Receptors (TKRs) and down-stream signaling pathways. This review paves the way for introducing a panel of miRNAs for the prediction of TKIs responses in lung cancer patients.

miR-129-2 upregulation induces apoptosis and promotes NSCLC chemosensitivity by targeting SOX4

Background

As one of the main causes of death worldwide, the treatment of non‐small‐cell lung cancer (NSCLC) is still unsatisfactory. This study aimed to explore the role of miR‐129‐2 in cell apoptosis and NSCLC chemosensitivity.

Methods

The effect of miR‐129‐2 on NSCLC was investigated using lung cancer cell lines (A549, NCl‐H23, and HCC827), a normal lung cell line (BEAS‐2B), and NSCLC tissues and adjacent healthy tissues. The oncogene SOX4 was verified as the target gene of miR‐129‐2 by luciferase reporter assay and real‐time polymerase chain reaction.

Results

miR‐129‐2 expression was downregulated in NSCLC tissues, NCl‐H23 cells, and A549 cells. miR‐129‐2 upregulation induced apoptosis in NCl‐H23 and A549 cells. miR‐129‐2 upregulation also inhibited NSCLC in a xenograft mouse model, which was related to downregulation of SOX4 expression. Furthermore, miR‐129‐2 and SOX4 were aberrantly expressed in the cisplatin‐resistant lung cancer cell line A549/DDP, and upregulation of miR‐129‐2 expression promoted cisplatin sensitivity in A549/DDP cells.

Conclusions

In conclusion, miR‐129‐2 expression was downregulated in NSCLC tissues and cell lines, and its upregulation induced cell apoptosis and promoted NSCLC chemosensitivity by regulating SOX4. Therefore, miR‐129‐2 can serve as a potential diagnostic and therapeutic target in NSCLC.

Long non-coding RNA prostate cancer-associated transcript 6 inhibited gefitinib sensitivity of non-small cell lung cancer by serving as a competing endogenous RNA of miR-326 to up-regulate interferon-alpha receptor 2

The critical roles of lncRNAs in drug resistance of malignancies have been widely recognized. This investigation aims to study the function of lncRNA PCAT6 in the resistance of non-small cell lung cancer (NSCLC) to gefitinib. In our study, we demonstrated that prostate cancer-associated transcript 6 (PCAT6) was upregulated in gefitinib-resistant NSCLC. PCAT6 knockdown inhibited gefitinib resistance of NSCLC, as indicated by decreased IC₅₀ value, proliferation, and metastasis, and increased cell apoptosis. Besides, PCAT6 could directly target miR-326 in gefitinib-resistant NSCLC cells and augment NSCLC resistance to gefitinib by serving as ceRNA of miR-326. Furthermore, interferon-alpha receptor 2 (IFNAR2) was validated as a downstream target of miR-326 and miR-326 reduced resistance to gefitinib by inhibiting IFNAR2 expression. Our investigation identified that PCAT6 enhanced gefitinib resistance of NSCLC via miR-326/IFNAR2 axis, which might offer a new therapeutic strategy against gefitinib resistance of NSCLC patients.

Construction of a Nomogram Based on lncRNA and Patient's Clinical Characteristics to Improve the Prognosis of Non-Small Cell Lung Cancer

Although the American Joint Commission on Cancer (AJCC) staging has been widely used to predict the survival of cancer patients, there are still some limitations. The high accuracy of lncRNA-based signature prediction has attracted widespread attention. The data were obtained from the RNA sequencing data of nonsmall cell lung cancer (NSCLC) in the Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DELs) and differentially expressed mRNAs (DEMs) were identified. Using univariate Cox proportional hazard regression (CPHR) analysis, least absolute shrinkage and selection operator method, and multivariate CPHR, 5 lncRNAs (LINC00460, LINC00857, LINC01116, RP11-253E3.3, and RP11-359E19.2) related to patient survival were successfully screened. Combined with age, gender, AJCC staging, and 5 lncRNAs, a nomogram with a better prognosis prediction ability than traditional parameters was constructed. Prognostic accuracy was evaluated using the receiver operating characteristic (ROC) curve and area under the ROC value. In addition, through co-expression analysis, we found that 5 lncRNA target genes have 34 DEMs. Gene ontology function analysis showed that these DEMs were mainly enriched in enzyme inhibitor activity and other aspects. Finally, these DEMs were found to be involved in the formation of the tumor immune microenvironment. In short, the nomogram based on 5 lncRNAs can effectively predict the overall survival rate of NSCLC and may guide the formulation of treatment plans for NSCLC.

Identification of lncRNA-miRNA-mRNA Networks Linked to Non-small Lung Cancer Resistance to Inhibitors of Epidermal Growth Factor Receptor

Background: Tyrosine kinase inhibitors that act against epidermal growth factor receptor (EGFR) show strong efficacy against non-small cell lung cancer (NSCLC) involving mutated EGFRs. However, most such patients eventually develop resistance to EGFR-TKIs. Numerous researches have reported that messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs) may be involved in EGFR-TKI resistance, but the comprehensive expression profile and competitive endogenous RNA (ceRNA) regulatory network between mRNAs and ncRNAs in EGFR-TKI resistance of NSCLC are incompletely known. We aimed to define a ceRNA regulatory network linking mRNAs and non-coding RNAs that may mediate this resistance.

Methods: Using datasets GSE83666, GSE75309 and GSE103352 from the Gene Expression Omnibus, we identified long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and mRNAs differentially expressed between NSCLC cells that were sensitive or resistant to EGFR-TKIs. The potential biological functions of the corresponding differentially expressed genes were analyzed based KEGG pathways. We combined interactions among lncRNAs, miRNAs and mRNAs in the RNAInter database with KEGG pathways to generate transcriptional regulatory ceRNA networks associated with NSCLC resistance to EGFR-TKIs. Kaplan-Meier analysis was used to assess the ability of core ceRNA regulatory sub-networks to predict the progression-free interval and overall survival of NSCLC. The expression of two core ceRNA regulatory sub-networks in NSCLC was validated by quantitative real-time PCR.

Results: We identified 8,989 lncRNAs, 1,083 miRNAs and 3,191 mRNAs that were differentially expressed between patients who were sensitive or resistant to the inhibitors. These DEGs were linked to 968 biological processes and 31 KEGG pathways. Pearson analysis of correlations among the DEGs of lncRNAs, miRNAs and mRNAs identified 12 core ceRNA regulatory sub-networks associated with resistance to EGFR-TKIs. The two lncRNAs ABTB1 and NPTN with the hsa-miR-150–5p and mRNA SERPINE1 were significantly associated with resistance to EGFR-TKIs and survival in NSCLC. These lncRNAs and the miRNA were found to be down-regulated, and the mRNA up-regulated, in a resistant NSCLC cell line relative to the corresponding sensitive cells.

Conclusion: In this study, we provide new insights into the pathogenesis of NSCLC and the emergence of resistance to EGFR-TKIs, based on a lncRNA-miRNA-mRNA network.

FOXO3-induced oncogenic lncRNA CASC9 enhances gefitinib resistance of non-small-cell lung cancer through feedback loop

Gefitinib is tyrosine kinase inhibitor of epidermal growth factor receptor, which exhibits notable clinical efficacy in non-small-cell lung cancer (NSCLC) treatment. However, gefitinib resistance is a critical obstacle for NSCLC targeted therapy. Here, we investigated the biological functions and mechanisms of lncRNA CASC9 in NSCLC gefitinib resistance. Screening analysis and RT-qPCR demonstrated that CASC9 was up-regulated in the gefitinib-resistant NSCLC cells (PC9/GR). Moreover, high-expression of CASC9 acted as an unfavorable factor for NSCLC patients. Functionally, CASC9 promoted the proliferation and gefitinib resistance of PC9/GR cells in vitro, and knockdown of CASC9 repressed the tumor growth in vivo. Mechanistically, CASC9 epigenetically promoted the FOXO3 expression via inhibiting miR-195-5p. In turn, transcription factor FOXO3 bound with the promoter region of CASC9 to enhance CASC9 transcriptional level, thereby forming CASC9/miR-195-5p/FOXO3 positive feedback loop. In conclusion, our research identified the regulation of CASC9/miR-195-5p/FOXO3 feedback loop on NSCLC gefitinib resistance, which might help researchers develop potential therapeutic targets for NSCLC.

RHPN1‑AS1 promotes ovarian carcinogenesis by sponging miR‑6884‑5p thus releasing TOP2A mRNA

Ovarian cancer, a severe lethal gynecological malignancy, is characterized by both high morbidity and mortality. Long noncoding RNAs (lncRNAs) have recently caused extensive concern due to their regulatory function in various human tumors. There are a mounting number of lncRNAs that are in extreme need of research, serving as biomarkers for diagnosis and therapy for ovarian cancer. In the present study, RT-qPCR was employed to detect how Rhophilin Rho GTPase binding protein 1 antisense RNA1 (RHPN1-AS1), miR-6884-5p and DNA topoisomerase IIα (TOP2A) are expressed in ovarian cancer tissues or cell lines. BrdU, MTT, colony formation and cell adhesion assays, caspase-3 activity, flow cytometry and wound healing assay were employed to assess cell proliferation, viability, colony number, adhesion, apoptosis and migration in ovarian cancer, respectively. RHPN1-AS1 was determined to be enriched in ovarian cancer tissues and cell lines. Silencing of RHPN1-AS1 was reported to increase cell apoptosis and impair cell proliferation, viability, colony number, adhesion and migration in vitro. Furthermore, RHPN1-AS1 was able to sponge miR-6884-5p which directly targets TOP2A in ovarian cancer. Notably, silencing of RHPN1-AS1 functionally reversed the oncogenic effect induced by the miR-6884-5p inhibitor, while the miR-6884-5p inhibitor markedly restored the inhibition of ovarian carcinogenesis modulated by silencing TOP2A in ovarian cancer. RHPN1-AS1 was found to promote ovarian carcinogenesis via sponging miR-6884-5p thus releasing TOP2A, and RHPN1-AS1 may act as a promising biomarker for the prognosis and therapy of ovarian cancer.

Genome-Wide Screening Identifies Prognostic Long Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis. Therefore, there is an urgent call for the investigation of novel biomarkers in HCC. In the present study, we identified 6 upregulated lncRNAs in HCC, including LINC01134, RHPN1-AS1, NRAV, CMB9-22P13.1, MKLN1-AS, and MAPKAPK5-AS1. Higher expression of these lncRNAs was correlated to a more advanced cancer stage and a poorer prognosis in HCC patients. Enrichment analysis revealed that these lncRNAs played a crucial role in HCC progression, possibly through a series of cancer-related biological processes, such as cell cycle, DNA replication, histone acetyltransferase complex, fatty acid oxidation, and lipid modification. Moreover, competing endogenous RNA (ceRNA) network analysis revealed that these lncRNAs could bind to certain miRNAs to promote HCC progression. Loss-of-function assays indicated that silencing of RHPN1-AS1 significantly suppressed HCC proliferation and migration. Though further validations are still needed, these identified lncRNAs could serve as valuable potential biomarkers for HCC prognosis.

LncRNA SNHG1 contributes to the cisplatin resistance and progression of NSCLC via miR-330-5p/DCLK1 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) are involved in the occurrence and progression of multiple cancers, including non-small cell lung cancer (NSCLC). Herein, we explored the exact role and underlying mechanism of lncRNA small nucleolar RNA host gene 1 (SNHG1) in NSCLC.

METHODS

The levels of SNHG1, microRNA-330-5p (miR-330-5p) and doublecortin-like kinase 1 (DCLK1) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was carried out to measure the chemoresistance and proliferation of NSCLC cells. The metastasis and apoptosis of NSCLC cells were examined by transwell migration and invasion assays and flow cytometry. Western blot assay was conducted to detect the levels of proliferation-associated proteins and DCLK1. The interaction between miR-330-5p and SNHG1 or DCLK1 was predicted by StarBase and microT_CDS databases. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to validate these interactions. In vivo chemosensitivity experiment was conducted to assess the function of SNHG1 in the chemoresistance of NSCLC in vivo.

RESULTS

SNHG1 was dramatically up-regulated in cisplatin (DDP)-resistant NSCLC tissues and cells. SNHG1 promoted the DDP resistance and malignant behaviors of NSCLC cells. SNHG1 functioned through targeting miR-330-5p, and si-SNHG1-mediated effects in NSCLC cells were attenuated by the addition of in-miR-330-5p. DCLK1 messenger RNA (mRNA) could directly bind to miR-330-5p, and miR-330-5p acted as a tumor suppressor in NSCLC through down-regulating DCLK1. SNHG1 silencing elevated the DDP sensitivity of NSCLC cells in vivo.

CONCLUSION

SNHG1 elevated DDP resistance and malignant potential of NSCLC cells through elevating the level of DCLK1 via sponging miR-330-5p.

Gefitinib reduces oocyte quality by disturbing meiotic progression

Gefitinib is a first-line anti-cancer drug for the treatment of advanced non-small cell lung cancer (NSCLC). It has been reported that gefitinib can generate several drug-related adverse effects, including nausea, peripheral edema, decreased appetite and rash. However, the reproductive toxicity of gefitinib has not been clearly defined until now. Here we assessed the effects of gefitinib on oocyte quality by examining the critical events and molecular changes of oocyte maturation. Gefitinib at 1, 2, 5 or 10 μM concentration was added to culture medium (M2). We found that gefitinib at its median peak concentration of 1 μM did not affect oocyte maturation, but 5 μM gefitinib severely blocked oocyte meiotic progression as indicated by decreased rates of germinal vesicle breakdown (GVBD) and polar body extrusion (PBE). We further showed that gefitinib treatment increased phosphorylation of CDK1 at the site of Try15, inhibited cyclin B1 entry into the nucleus, and disrupted normal spindle assembly, chromosome alignment and mitochondria dynamics, finally leading to the generation of aneuploidy and early apoptosis of oocytes. Our study reported here provides valuable evidence for reproductive toxicity of gefitinib administration employed for the treatment of cancer patients.

LncRNA MIR205HG regulates melanomagenesis via the miR-299-3p/VEGFA axis

In this study, we investigated the role of lncRNA MIR205HG in melanomagenesis. Quantitative real-time PCR (qRT-PCR) analysis showed that MIR205HG levels were significantly upregulated in melanoma cell lines compared to normal human melanocytes. Similarly, MIR205HG levels were significantly higher melanoma tissues than adjacent normal skin tissues (n=30). CCK-8 and flow cytometry assays showed that MIR205HG knockdown significantly decreased the viability of melanoma cells. Dual luciferase reporter and RNA pull-down assays confirmed that MIR205HG directly binds to microRNA (miR)-299-3p. Targetscan analysis and dual luciferase reporter assays showed that miR-299-3p directly binds to the 3'UTR of VEGFA mRNA. Wound healing and transwell invasion assays showed that MIR205HG knockdown decreased in vitro migration and invasiveness of melanoma cells, and these effects were reversed by treatment with miR-299-3p inhibitor. MIR205HG-silenced melanoma cells showed increased miR-299-3p expression and lower levels of both VEGFA mRNA and protein. Tumor volumes were significantly smaller in nude mice xenografted with MIR205HG knockdown melanoma cells than the controls. These results demonstrate that MIR205HG supports melanoma growth via the miR-299-3p/VEGFA axis. This makes MIR205HG a potential therapeutic target for the treatment of melanoma.

LncRNA APCDD1L-AS1 induces icotinib resistance by inhibition of EGFR autophagic degradation via the miR-1322/miR-1972/miR-324-3p-SIRT5 axis in lung adenocarcinoma

BACKGROUND

Epidermal growth factor receptor-tyrosinase kinase inhibitor (EGFR-TKI) resistance is the major obstacle in the treatment of lung adenocarcinoma (LUAD) patients harboring EGFR-sensitive mutations. However, the long non-coding RNAs (lncRNAs) related to EGFR-TKIs resistance and their functional mechanisms are still largely unknown. This study aimed to investigate the role and regulatory mechanism of lncRNA APCDD1L-AS1 in icotinib resistance of lung cancer.

METHODS

Molecular approaches including qRT-PCR, MTT assay, colony formation, RNA interference and cell transfection, RNA immunoprecipitation (RIP), dual luciferase reporter assay, RNA fluorescence in situ hybridization, TUNEL assay, flow cytometry, immunoblotting, xenograft model and transcriptome sequencing were used to investigate the mechanism of APCDD1L-AS1 in icotinib resistance.

RESULTS

A novel lncRNA, APCDD1L-AS1 was identified as the most significantly upregulated lncRNA in icotinib-resistant LUAD cells by the transcriptome sequencing and differential lncRNA expression analysis. We found that APCDD1L-AS1 not only promoted icotinib resistance, but also upregulated the protein expression level of EGFR. Mechanistically, APCDD1L-AS1 promoted icotinib resistance and EGFR upregulation by sponging with miR-1322/miR-1972/miR-324-3p to remove the transcription inhibition of SIRT5. Furthermore, SIRT5 elevated EGFR expression and activation by inhibiting the autophagic degradation of EGFR, finally promoting icotinib resistance. Consistently, the autophagy initiator rapamycin could decrease EGFR levels and increase the sensitivity of icotinib-resistant LUAD cells to icotinib.

CONCLUSION

APCDD1L-AS1 could promote icotinib resistance by inhibiting autophagic degradation of EGFR via the miR-1322/miR-1972/miR-324-3p-SIRT5 axis. The combination of autophagy initiator and EGFR-TKIs might serve as a potential new strategy for overcoming EGFR-TKIs resistance in LUAD patients.

Construction and validation of a novel prognostic signature of microRNAs in lung adenocarcinoma

MicroRNA (miRNA, miR) has been reported to be highly implicated in a wide range of biological processes in lung cancer (LC), and identification of differentially expressed miRNAs between normal and LC samples has been widely used in the discovery of prognostic factors for overall survival (OS) and response to therapy. The present study was designed to develop and evaluate a miRNA-based signature with prognostic value for the OS of lung adenocarcinoma (LUAD), a common histologic subtype of LC. In brief, the miRNA expression profiles and clinicopathological factors of 499 LUAD patients were collected from The Cancer Genome Atlas (TCGA) database. Kaplan-Meier (K-M) survival analysis showed significant correlations between differentially expressed miRNAs and LUAD survival outcomes. Afterward, 1,000 resample LUAD training matrices based on the training set was applied to identify the potential prognostic miRNAs. The least absolute shrinkage and selection operator (LASSO) cox regression analysis was used to constructed a six-miRNA based prognostic signature for LUAD patients. Samples with different risk scores displayed distinct OS in K-M analysis, indicating considerable predictive accuracy of this signature in both training and validation sets. Furthermore, time-dependent receiver operating characteristic (ROC) analysis demonstrated the nomogram achieved higher predictive accuracy than any other clinical variables after incorporating the clinical information (age, sex, stage, and recurrence). In the stratification analysis, the prognostic value of this classifier in LUAD patients was validated to be independent of other clinicopathological variables, such as age, gender, tumor recurrence, and early stage. Gene set annotation analyses were also conducted through the Hallmark gene set and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, indicating target genes of the six miRNAs were positively related to various molecular pathways of cancer, such as hallmark UV response, Wnt signaling pathway and mTOR signaling pathway. In addition, fresh cancer tissue samples and matched adjacent tissue samples from 12 LUAD patients were collected to verify the expression of miR-582's target genes in the model, further revealing the potential relationship between SOX9, RASA1, CEP55, MAP4K4 and LUAD tumorigenesis, and validating the predictive value of the model. Taken together, the present study identified a robust signature for the OS prediction of LUAD patients, which could potentially aid in the individualized selection of therapeutic approaches for LUAD patients.

STAT1-induced upregulation of lncRNA RHPN1-AS1 predicts a poor prognosis of hepatocellular carcinoma and contributes to tumor progression via the miR-485/CDCA5 axis

Long noncoding RNAs (lncRNAs) act as a critical regulator in tumor progression, but few lncRNAs have been functionally characterized in hepatocellular carcinoma (HCC). Using The Cancer Genome Atlas datasets and bioinformatic technology, we screened and identified a novel HCC-related lncRNA, RHPN1 antisense RNA 1 (RHPN1-AS1). We found that the levels of RHPN1-AS1 were distinctly upregulated in both HCC tissues and cell lines. RHPN1-AS1 was activated by the transcription factor STAT1. Clinical investigations suggested that higher levels of RHPN1-AS1 were distinctly correlated with histologic grade, advanced tumor, node, metastasis stage, and poorer clinical prognosis. Multivariate assays identified high RHPN1-AS1 expression as an unfavorable prognostic biomarker for patients with HCC. Functional study revealed that knockdown of RHPN1-AS1 was able to suppress cells proliferation and metastasis, and promote cell apoptosis. Further mechanistic investigation suggested that RHPN1-AS1 could promote CDCA5 expressions by functioning as a competing endogenous RNA for miR-485. This interaction resulted in consequentially suppression of HCC cells proliferation, migration, and invasion. Our findings for the first time illustrate how RHPN1-AS1 displayed its tumor-promotive roles in HCC and may offer a new biomarker and a potential therapeutic target for patients with HCC.

LncRNA RHPN1-AS1 accelerates proliferation, migration, and invasion via regulating miR-485-5p/BSG axis in hepatocellular carcinoma

It is reported that long noncoding RNA RHPN1-AS1 (lncRNA RHPN1-AS1) functions as an oncogene among multiple types of cancers; however, the effect of lncRNA RHPN1-AS1 in hepatocellular carcinoma (HCC) is left to be investigated. The main purpose of this work was to study the effects of lncRNA RHPN1-AS1/miR-485-5p system on proliferation, migration, and invasion in HCC and future investigate the latent mechanisms. Our work found that lncRNA RHPN1-AS1 was observably up-regulated in HCC tissues and cell lines, especially HCCLM3 and SMMC-7721 cells. LncRNA RHPN1-AS1 knockdown decreased the capacity of proliferation, invasion, and migration in HCCLM3 and SMMC-7721 cells, which could be crippled by miR-485-5p inhibitor. Besides, the expression of basigin (BSG) was decreased after lncRNA RHPN1-AS1 silence, indicating the function of lncRNA RHPN1-AS1/miR-485-5p/BSG axis in HCC progression. Our study opens novel insights to help understand the mechanisms of lncRNA RHPN1-AS1/miR-485-5p/BSG axis in HCC progression, which may provide a new therapeutic target for HCC treatment.

Overexpression of CTEN is associated with gefitinib resistance in non-small cell lung cancer

COOH-terminus tensin-like molecule (CTEN) is a member of the tensin family, which is considered to be one of the novel proto-oncogenes involved in tumorigenesis and cancer progression. However, the mechanisms of CTEN in acquired resistance of non-small cell lung cancer (NSCLC) remain relatively unknown. The aim of the present study was to understand the roles of CTEN in acquired gefitinib resistance of NSCLC. The present study investigated the expression level of CTEN using reverse transcription-quantitative polymerase chain reaction and Western blot analysis. Cell Counting kit-8 and colony-formation assays were performed to evaluate the proliferative and colony-formative abilities of PC9 and PC9/GR cells in vitro. Mouse xenograft models were used to assess the growth of PC9/GR cells in vivo. A gefitinib-resistant NSCLC cell line (PC9/GR) was established, and the protein and mRNA expression levels of CTEN were observed to be higher in PC9/GR cells than in PC9 cells. Notably, the sensitivity of PC9/GR cells to gefitinib was observed to be decreased when CTEN was overexpressed, while PC9/GR cells with CTEN-downregulation showed markedly enhanced sensitivity to gefitinib. In vitro proliferation and colony formation assays revealed that increased CTEN markedly promoted the cell proliferative and colony-forming capacities of PC9 and PC9/GR cells, and CTEN-silencing inhibited the cell proliferative and colony-forming abilities of the PC9 and PC9/GR cells. Notably, deficient expression of CTEN notably retarded the growth of PC9/GR xenografts in vivo. In addition, the plasma mRNA expression of CTEN was notably elevated in patients with NSCLC with acquired gefitinib resistance. Overexpression of CTEN is associated with acquired gefitinib resistance in NSCLC. CTEN may be investigated as a potential therapeutic target for the treatment of patients with NSCLC with acquired gefitinib resistance.

Long non-coding RNA CASC9 promotes gefitinib resistance in NSCLC by epigenetic repression of DUSP1

Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, has greatly affected clinical outcomes in non-small cell lung cancer (NSCLC) patients. The long noncoding RNAs (lncRNAs) are known to regulate tumorigenesis and cancer progression, but their contributions to NSCLC gefitinib resistance remain poorly understood. In this study, by analyzing the differentially expressed lncRNAs in gefitinib-resistant cells and gefitinib-sensitive cells in the National Institute of Health GEO dataset, we found that lncRNA CASC9 expression was upregulated, and this was also verified in resistant tissues. Gain and loss of function studies showed that CASC9 inhibition restored gefitinib sensitivity both in vitro and in vivo, whereas CASC9 overexpression promoted gefitinib resistance. Mechanistically, CASC9 repressed the tumor suppressor DUSP1 by recruiting histone methyltransferase EZH2, thereby increasing the resistance to gefitinib. Furthermore, ectopic expression of DUSP1 increased gefitinib sensitivity by inactivating the ERK pathway. Our results highlight the essential role of CASC9 in gefitinib resistance, suggesting that the CASC9/EZH2/DUSP1 axis might be a novel target for overcoming EGFR-TKI resistance in NSCLC.

New insights into long non-coding RNAs in non-small cell lung cancer

Lung cancer is a malignant tumor that seriously threatens human life and health. Non-small cell lung cancer (NSCLC) accounts for 85 % of all lung cancer cases, and its global 5-year survival rate is only approximately 5%. Thus, the identification of new prognostic biomarkers has become one of the most urgent challenges in NSCLC research. Long noncoding RNAs (LncRNAs) are a kind of noncoding RNA whose length exceeds 200 nucleotides (nt). LncRNAs are transcribed by RNA pol II and can be subjected to posttranscriptional modifications such as blocking, polyadenylation and splicing; moreover, their expression profiles are more specific than those of mRNAs. Emerging evidence confirms that lncRNAs are associated with the occurrence and development of NSCLC and play an important role in NSCLC drug resistance. The purpose of this review was to describe the roles of lncRNAs in the development, diagnosis and prognosis of NSCLC and to explore new evidence of lncRNAs in the treatment of NSCLC drug resistance. This review provides a new perspective of lncRNAs in the treatment of NSCLC.

RHPN1-AS1 Drives the Progression of Hepatocellular Carcinoma via Regulating miR-596/IGF2BP2 Axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most deadly cancer types worldwide, and its incidence is high in China. Multiple long non-coding RNAs (lncRNAs) have been recently identified as crucial oncogenic factors or tumor suppressors. In this study, we explored the effects of LncRNA RHPN1 antisense RNA 1 (RHPN1-AS1) on the progression of HCC.

METHODS

Expression levels of RHPN1-AS1 and miR-596 in HCC samples were measured by qRT-PCR. The association between pathological indexes and the expression level of RHPN1-AS1 was also analyzed. Human HCC cell lines Huh7 and SMMC-7721 were used as cell models. CCK-8 and colony formation assays were performed to assess the effect of RHPN1-AS1 on HCC cell line proliferation. The flow cytometer instrument was used to study the effect of RHPN1-AS1 on apoptosis of HCC cells. The transwell assay was conducted to detect the effect of RHPN1-AS1 on migration and invasion. Furthermore, luciferase reporter assay was used to confirm targeting of miR-596 by RHPN1-AS1. Additionally, the regulatory function of RHPN1-AS1 on insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) was detected by western blot.

RESULTS

The expression level of RHPN1-AS1 in HCC samples was observed to significantly increase compared with normal tissues and its high expression was correlated with unfavorable pathological indexes. Highly expressed RHPN1-AS1 was associated with shorter overall survival time. RHPN1-AS1 overexpression remarkably accelerated proliferation and metastasis of HCC cells, while reduced apoptosis. Accordingly, RHPN1-AS1 knockdown suppressed the malignant phenotypes of HCC cells. RHPN1-AS1 overexpression significantly reduced miR-596 expression by sponging it, but enhanced IGF2BP2 expression.

CONCLUSION

RHPN1-AS1 acts as a sponge of tumor suppressor miR-596 in HCC that can indirectly enhance the IGF2BP2 expression and function as an oncogenic lncRNA.

LncRNA RHPN1-AS1 Promotes Cell Proliferation, Migration and Invasion Through Targeting miR-7-5p and Activating PI3K/AKT/mTOR Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a severe disease with high mortality in the world. Emerging evidence has suggested that lncRNAs play an important role in cancer progression, including HCC. This study aimed to comprehensively investigate the effect of lncRNA RHPN1 antisense RNA 1 (RHPN1-AS1) on HCC and its underlying molecular mechanism. In this study, we evaluated the expressions of lncRNA RHPN1-AS1 and miR-7-5p by qRT-RCR in both HCC tissue and HCC cells. Our findings showed that lncRNA RHPN1-AS1 was upregulated in HCC tissue and HCC cells, while miR-7-5p was downregulated. LncRNA RHPN1-AS1 expression in HCC patients was closely related to vascular invasion, tumor-node-metastasis (TNM) stage and barcelona clinic liver cancer (BCLC) stage. Furthermore, we quantified cell clone-formation ability, proliferation, migration and invasion of HCCLM3 and MHCC97 H cells using several assays (colony formation assay, 5-Ethynyl-2′-deoxyuridine (EdU) assay and transwell assay, respectively). Functional experiments confirmed that silencing lncRNA RHPN1-AS1 inhibited cell proliferation, migration and invasion in HCCLM3 and MHCC97 H cells. After that, bioinformatics analysis, dual luciferase reporter gene assay, qRT-PCR and western blot were used to investigate the molecular mechanism of lncRNA RHPN1-AS1 on HCC. Mechanistically, the rescue experiments demonstrated that miR-7-5p inhibitor reversed the inhibition effect of silencing lncRNA RHPN1-AS1 on HCCLM3 cells proliferation, migration and invasion. Moreover, silencing lncRNA RHPN1-AS1 also inhibited the activation of PI3K/AKT/mTOR pathway. Taken together our findings demonstrated that lncRNA RHPN1-AS1 could facilitate cell proliferation, migration and invasion via targeting miR-7-5p and activating PI3K/AKT/mTOR pathway in HCC.

Coexpression Network Analysis Identifies a Novel Nine-RNA Signature to Improve Prognostic Prediction for Prostate Cancer Patients

Background

Prostate cancer (PCa) is the most common malignancy and the leading cause of cancer death in men. Recent studies suggest the molecular signature was more effective than the clinical indicators for the prognostic prediction, but all of the known studies focused on a single RNA type. The present study was to develop a new prognostic signature by integrating long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) and evaluate its prognostic performance.

Methods

The RNA expression data of PCa patients were downloaded from The Cancer Genome Atlas (TCGA) or Gene Expression Omnibus database (GSE17951, GSE7076, and GSE16560). The PCa-driven modules were identified by constructing a weighted gene coexpression network, the corresponding genes of which were overlapped with differentially expressed RNAs (DERs) screened by the MetaDE package. The optimal prognostic signature was screened using the least absolute shrinkage and selection operator analysis. The prognostic performance and functions of the combined prognostic signature was then assessed.

Results

Twelve PCa-driven modules were identified using TCGA dataset and validated in the GSE17951 and GSE7076 datasets, and six of them were considered to be preserved. A total of 217 genes in these 6 modules were overlapped with 699 DERs, from which a nine-gene prognostic signature was identified (including 3 lncRNAs and 6 mRNAs), and the risk score of each patient was calculated. The overall survival was significantly shortened in patients having the risk score higher than the cut-off, which was demonstrated in TCGA (p = 5.063E − 03) dataset and validated in the GSE16560 (p = 3.268E − 02) dataset. The prediction accuracy of this risk score was higher than that of clinical indicators (the Gleason score and prostate-specific antigen) or the single RNA type, with the area under the receiver operator characteristic curve of 0.945. Besides, some new therapeutic targets and mechanisms (MAGI2-AS3-SPARC/GJA1/CYSLTR1, DLG5-AS1-DEFB1, and RHPN1-AS1-CDC45/ORC) were also revealed.

Conclusion

The risk score system established in this study may provide a novel reliable method to identify PCa patients at a high risk of death.

Prognostic potential of lncRNA RHPN1-AS1 in glioma

Expression level of long non-coding RNA (lncRNA) RHPN1-AS1 in glioma tissues was detected to determine potential risk factors influencing prognosis of glioma. This study aimed to clarify the molecular mechanisms underlying tumorigenesis of glioma and thus to improve therapeutic efficacy of glioma. RHPN1-AS1 levels in glioma tissues (n=105) and normal brain tissues (n=105) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between RHPN1-AS1 level and pathological indicators of glioma patients was analyzed. Glioma patients were followed up for 5 years. Overall survival (OS) and relapse-free survival (RFS) in glioma patients were tested by Kaplan-Meier and log-rank method. Potential factors influencing prognosis of glioma were analyzed by Cox regression model. RHPN1-AS1 was upregulated in glioma tissues. Its level was correlated to histological grade, Karnofsky (KPS) score and postoperative recurrence of glioma patients, rather than sex, age, pathological and tumor size. Glioma patients expressing high level of RHPN1-AS1 suffered worse OS and RFS than those with low level. Advanced histological grade, KPS score <80 and high level of RHPN1-AS1 were considered to be risk factors influencing postoperative prognosis of glioma. High level of RHPN1-AS1 is an independent risk factor for poor prognosis of glioma, which may be utilized as a prognostic hallmark.

The functional role of long non-coding RNAs and their underlying mechanisms in drug resistance of non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most commonly diagnosed solid cancer and the main origin of cancer-related deaths worldwide. Current strategies to treat advanced NSCLC are based on a combined approach of targeted therapy and chemotherapy. But most patients will eventually get resistance to either chemotherapy or targeted therapy, leading to the poor prognosis. The mechanism of NSCLC drug resistance is inconclusive and is affected by multiple factors. Long non-coding RNAs (LncRNAs) are non-coding RNAs (ncRNAs) longer than 200 nucleotides. Recent studies show that lncRNAs are involved in many cellular physiological activities, including drug resistance of NSCLC. It is of great clinical significance to understand the specific mechanisms and the role of lncRNAs in it.

CONCLUSIONS

Herein, we focus on the functional roles and the underlying mechanisms of lncRNAs in acquired drug resistance of NSCLC. LncRNAs have potential values as novel prognostic biomarkers and even therapeutic targets in the clinical management of NSCLC.

Mechanisms of drug resistance mediated by long non-coding RNAs in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is the most prevalent form of lung cancer and has a poor five-year survival rate of 15%. Chemotherapy and targeted therapies have significantly improved patients' prognosis. Nevertheless, after a successful initial response, some patients relapse when cancer cells become resistant to drug treatments, representing an important clinical limitation. Therefore, investigating the mechanisms of drug resistance is of significant importance. Recently, considerable attention has been given to long non-coding RNAs (lncRNAs), a heterogeneous class of regulatory molecules that play essential roles in tumorigenesis by modulating genes and signalling pathways involved in cell growth, metastasis and drug response. In this article, we review recent research findings on the role of lncRNAs in drug resistance in NSCLC, highlighting their mechanisms of action.

lncRNA RHPN1-AS1 Promotes Ovarian Cancer Growth and Invasiveness Through Inhibiting miR-1299

Background

Ovarian cancer (OC) is a big threat for public health. However, the molecular mechanism underlying OC development and progression remains unclear. Although the importance of lncRNA in cancer has been proven, how lncRNA is involved in OC is waiting for further investigation.

Materials and Methods

qRT-PCR was performed to test expression level. CCK8 and colony formation were conducted to analyze proliferation. Transwell was conducted to measure migration and invasion. Luciferase reporter assay and pulldown assay were utilized to validate RNA interaction.

Results

lncRNA RHPN1-AS1 was highly expressed in OC tissues. RHPN1-AS1 was positively correlated with OC progression and its high expression indicated a low survival rate. Moreover, knockdown of RHPN1-AS1 significantly inhibited the proliferation, migration and invasion of OC cells, and bioinformatics analysis identified that miR-1299 was sponged by RHPN1-AS1 in OC cells. Knockdown of RHPN1-AS1 markedly promoted miR-1299 expression. Of note, inhibition of miR-1299 reversed the roles of RHPN1-AS1 silencing on suppressing proliferation, migration and invasion.

Conclusion

Our study demonstrates that RHPN1-AS1 promotes OC progression via sponging miR-1299, suggesting RHPN1-AS1 may be a novel therapeutic target.

RHPN1-AS1 promotes cell proliferation and migration via miR-665/Akt3 in ovarian cancer

Recent efforts have revealed that long non-coding RNAs exert crucial roles in cancer initiation and progression. RHPN1-AS1 is a 2030 bp transcript from human chromosome 8q24, and involved in tumorigenesis in uveal melanoma and non-small cell lung cancer, but it remains unknown in ovarian cancer. This study focused on the role of RHPN1-AS1 in ovarian cancer and found that RHPN1-AS1 was up-regulated in ovarian cancer tissues and cell lines. Overexpression of RHPN1-AS1 promoted ovarian cancer cell proliferation, migration, and invasion. Mechanistically, overexpression of RHPN1-AS1 decreased the expression of miR-665 and subsequently promoted the expression of Akt3 at posttranscriptional level. Taken together, RHPN1-AS1 positively regulated the expression of Akt3 through sponging miR-665, and exerted an oncogenic role in ovarian cancer progression, and indicates that RHPN1-AS1 may be a potential therapeutic target in ovarian cancer.

Genome-wide identification and characterization of long non-coding RNAs involved in acquired resistance to gefitinib in non-small-cell lung cancer

Acquired resistance is a major obstacle to the therapeutic efficacy of gefitinib in non-small-cell lung cancer (NSCLC). Current knowledge about the role of long non-coding RNAs (lncRNAs) in this phenomenon is insufficient. In this study, we searched RNA sequencing data for lncRNAs associated with acquired resistance to gefitinib in NSCLC, and constructed a functional lncRNA-mRNA co-expression network and protein-protein interaction (PPI) network to analyze their putative target genes and biological functions. The expression levels of 14 outstanding dysregulated lncRNAs and mRNA were verified using real-time PCR. Changes in the expression levels of 39 lncRNAs and 121 mRNAs showed common patterns in our two pairs of gefitinib-sensitive and gefitinib-resistant NSCLC cell lines. The co-expression network included 1235 connections among these common differentially expressed lncRNAs and mRNAs. The significantly enriched signaling pathways based on dysregulated mRNAs were mainly involved in the Hippo signaling pathway; proteoglycans in cancer; and valine, leucine, and isoleucine biosynthesis. The results show that LncRNAs play an important part in acquired gefitinib resistance in NSCLC by regulating mRNA expression and function, and may represent potential new molecular biomarkers and therapeutic targets for gefitinib-resistant NSCLC.

Long non-coding RNA RHPN1-AS1 promotes tumorigenesis and metastasis of ovarian cancer by acting as a ceRNA against miR-596 and upregulating LETM1

Background: In recent decades, long non-coding RNAs (lncRNAs) have been reported as crucial functional regulators involved in ovarian cancer. In the present study, we explored how lncRNA RHPN1-AS1 influences the progression of epithelial ovarian cancer (EOC) through tumor cell-dependent mechanisms.

Results: The expression of RHPN1-AS1 in EOC tissues was higher than that in para-cancerous control tissues. High expression of RHPN1-AS1 was closely associated with poor prognosis in EOC patients. N6-methyladenosine (m6A) improved the stability of RHPN1-AS1 methylation transcript by reducing RNA degradation, which resulted in upregulation of RHPN1-AS1 in EOC. In vitro and in vivo functional experiments showed that RHPN1-AS1 promoted EOC cell proliferation and metastasis. RHPN1-AS1 acted as a ceRNA to sponge miR-596, consequently increasing LETM1 expression and activating the FAK/PI3K/Akt signaling pathway.

Conclusion: RHPN1-AS1-miR-596-LETM1 axis plays a crucial role in EOC progression. Our findings may provide promising drug targets for EOC treatment.

Methods: We determined the aberrantly expressed lncRNAs in EOC via microarray analysis and validated RHPN1-AS1 expression by qRT-PCR. The RHPN1-AS1-miR-596-LETM1 axis was examined by dual-luciferase reporter assay and RIP assay. The mechanism of RHPN1-AS1 was investigated through gain- and loss-of-function studies both in vivo and in vitro.

Long noncoding RNA RHPN1-AS1 promotes colorectal cancer progression via targeting miR-7-5p/OGT axis

Background

Rhophilin Rho GTPase binding protein 1 antisense RNA 1 (RHPN1-AS1) is a newly discovered oncogene in several diseases, such as breast cancer, non-small cell lung cancer and uveal melanoma. Nevertheless, its molecular role in colorectal cancer (CRC) remains unknown. This paper explored the role of RHPN1-AS1 in CRC progression.

Methods

qRT-PCR was used to detect relevant RNAs expression. CCK-8, EdU, flow cytometry, Transwell and western blot assays were performed to investigate the function of RHPN1-AS1 in CRC cells. Xenograft model was constructed to evaluate the effects of RHPN1-AS1 on tumor growth in vivo. Mechanical experiments were performed to investigate the relationship between relative genes.

Results

RHPN1-AS1 was significantly overexpressed in CRC cell lines. Knockdown of RHPN1-AS1 could inhibit cell proliferation, while stimulating cell apoptosis in vitro. Cell migration and invasion abilities were greatly suppressed after silencing RHPN1-AS1. Besides, signal transducer and activator of transcription 3 (STAT3) served as transcription factor of RHPN1-AS1. Moreover, miR-7-5p was identified as a target of RHPN1-AS1 and was negatively regulated by RHPN1-AS1 in CRC. MiR-7-5p inhibition rescued the oncogenic function of RHPN1-AS1. Additionally, O-GlcNAcylation transferase (OGT) was the downstream target of miR-7-5p. OGT overexpression could abrogate the anti-tumor effects of RHPN1-AS1 knockdown on CRC.

Conclusion

RHPN1-AS1 regulates CRC by mediating OGT through sponging miR-7-5p, suggesting that RHPN1-AS1 might be a potential therapeutic target for CRC.

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

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

Long non-coding RNA in lung cancer

Lung cancer is the leading cause of cancer-related death worldwide. Owing to the difficulty in early diagnosis and the lack of effective treatment strategies, the 5-year survival rates for lung cancer remain very low. With the development of whole genome and transcriptome sequencing technology, long non-coding RNA (lncRNA) has attracted increasing attention. LncRNAs regulate gene expression at the epigenetic, transcriptional and post-transcriptional levels and are widely involved in a variety of diseases, including tumorigenesis. In lung cancer studies, multiple differentially expressed lncRNAs have been identified; several lncRNAs were identified as oncogenic lncRNAs with tumor-driving effects, while other lncRNAs play a role in tumor inhibition and are called tumor-suppressive lncRNAs. These tumor-suppressive lncRNAs are involved in multiple physiological processes such as cell proliferation, apoptosis, and metastasis and thus participate in tumor progression. In this review, we discussed the oncogenic and tumor-suppressive lncRNAs in lung cancer, as well as their biological functions and regulatory mechanisms. Furthermore, we found the potential significance of lncRNAs in clinical diagnosis and treatment.

LncRNA RHPN1-AS1 Targeting miR-625/REG3A Promotes Cell Proliferation And Invasion Of Glioma Cells

Introduction

Glioma arises from the proliferation of neuroglial cells differentiated from the ectoderm. Evidence has confirmed that differentially expressed long non-coding RNAs (lncRNAs) may be involved in the development and progression of various tumors. The present study aimed to explore the biological function of lncRNA RHPN1-AS1 in glioma.

Materials and methods

The expressions of RHPN1-AS1 in glioma tissues and cells were examined using RT-PCR. Colony formation assay, MTT assay, wound healing assay and transwell assay were performed to detect cell cloning efficiency, proliferation, migration and invasion of glioma cells, respectively. Western blot was applied to assess the expression levels of migration-related and invasion-related proteins. Online bioinformatic tools and luciferase reporter assay were, respectively, employed to predict and verify the downstream target microRNA/gene of RHPN1-AS1.

Results

RHPN1-AS1 was up-regulated in glioma tissues and cells. The cell proliferation, migration and invasion of glioma were inhibited when the expression of RHPN1-AS1 was down-regulated in glioma cells. The expressions of migration-related and invasion-related proteins were also suppressed in siRHPN1-AS1 groups. Furthermore, we predicted and verified that RHPN1-AS1 was directly targeted to miR-625-5p/REG3A. Our study demonstrated that the knockdown of RHPN1-AS1 inhibited the proliferation, migration and invasion activity of glioma cells via regulating miR-625-5p/REG3A expression.

Conclusion

The results revealed that the lncRNA RHPN1-AS1 may be a molecular target in glioma therapy.

LncRNA RHPN1-AS1 promoted cell proliferation, invasion and migration in cervical cancer via the modulation of miR-299-3p/FGF2 axis

AIMS

This study aims to determine the biological function and underlying mechanisms of lncRNA RHPN1 antisense RNA1 (RHPN1-AS1) in cervical cancer cell proliferation, invasion and migration.

MAIN METHODS

Gene expression was analysed by quantitative real-time PCR; protein levels were determined by western blot assay; in vitro functional assays determined the cervical cancer cell progression; in vivo tumor growth of cervical cancer cell was determined in nude mice xenograft models.

KEY FINDINGS

The results showed that RHPN1-AS1 was up-regulated in cervical cancer tissues and cell lines. In vitro functional assays demonstrated that RHPN1-AS1 overexpression promoted SiHa cell proliferation, invasion and migration; while RHPN1-AS1 knockdown showed the opposite effects. In vivo study showed that RHPN1-AS1 knockdown suppressed tumor growth in the nude mice. Further investigation showed that miR-299-3p was targeted and inversely regulated by RHPN1-AS1. In addition, miR-299-3p targeted the 3' untranslated region of fibroblast growth factor 2 (FGF2) to suppress its expression. The rescue experiments showed that the enhanced effects of RHPN1-AS1 overexpression on cell proliferation, growth, invasion and migration in SiHa cells were significantly attenuated by miR-299-3p overexpression or FGF2 inhibition. On the other hand, knockdown of miR-299-3p and overexpression of FGF2 both significantly increased cell proliferation, growth, invasion and migration in SiHa cells transfected with RHPN1-AS1 siRNA.

SIGNIFICANCE

In conclusion, our results revealed that RHPN1-AS1 promoted cervical cancer progression via targeting miR-299-3p/FGF2 axis. Our data suggested that RHPN1-AS1/miR-299-3p/FGF2 axis may be a promising target for cervical cancer treatment.

Knockdown of TUG1 by shRNA inhibited renal cell carcinoma formation by miR-299-3p/VEGF axis in vitro and in vivo

Renal cell carcinoma (RCC) is one of the top ten deadly malignancies in the world. The long non-coding RNA taurine up-regulated gene 1 (TUG1) is a transcript that is up-regulated by taurine. There is ample evidence that TUG1 plays a crucial role in the progression of various cancers. This study aimed to investigate the role of TUG1 in RCC and its underlying molecular mechanisms. In the current study, knockdown of TUG1 by shRNA (sh-TUG1) significantly inhibited proliferation, invasion, migration and EMT processes of ACHN cells and OS-RC-2 cells, and induced apoptosis. Besides, bioinformatics analysis revealed that miR-299-3p is a target of TUG1. TUG1 overexpression (LV-TUG1) significantly inhibited the expression of miR-299-3p, whereas sh-TUG1 showed the opposite effect. Dual luciferase reporter assay further confirmed the targeting relationship between TUG1 and miR-299-3p. In addition, vascular endothelial growth factor (VEGFA) is a target of miR-299-3p. Knockdown of VEGFA (si-VEGFA) significantly inhibited the proliferation and motility of ACHN cells, and induced apoptosis. RT-qPCR results showed that sh-TUG1 similarly inhibited VEGFA expression. Further functional analysis indicated that sh-TUG1 inhibited tumorigenesis by down-regulating VEGFA levels. However, LV-TUG1 showed the opposite effects. Furthermore, animal experiments have shown that sh-TUG1 inhibited tumor growth and metastasis and induces apoptosis in vivo. These results indicate that sh-TUG1 inhibited renal cell carcinoma formation by miR-299-3p/VEGF axis in vitro and in vivo. Taken together, all of these results reveal a novel mechanism of TUG1 in RCC tumorigenesis, suggesting that targeted drugs for TUG1 provides a new direction for the treatment of RCC.

Silencing of the long non-coding RNA RHPN1-AS1 suppresses the epithelial-to-mesenchymal transition and inhibits breast cancer progression

Breast cancer (BC) is a frequently diagnosed malignancy in women. Increasing evidence implicates mis-expression of the long non-coding RNA (lncRNA) RHPN1 antisense RNA 1 (RHPN1-AS1) in the development of multiple cancer types. However, little is known about the expression pattern and function of lncRNA RHPN1-AS1 in the pathobiology of BC. We evaluated the expression of RHPN1-AS1 in The Cancer Genome Atlas dataset, and analyzed associations between RHPN1-AS1 expression and clinicopathologic features of BC patients. Additionally, we compared the expression of RHPN1-AS1 between BC and breast non-tumor samples via quantitative real-time polymerase chain reaction, and in situ hybridization, and evaluated the prognostic value of RHPN1-AS1 in a BC tissue microarray. We examined the impact of RHPN1-AS1 knockdown on proliferation, migration, and invasion of BC cells in vitro, and tumor growth in vivo. Bioinformatics analyses were used to predict the function of RHPN1-AS1 in BC. RHPN1-AS1 expression was upregulated in BC and elevated RHPN1-AS1 expression was strongly associated with poor prognosis of BC patients. Moreover, both univariate and multivariate analyses revealed that RHPN1-AS1 was a significant and independent predictor of BC prognosis. Functionally, RHPN1-AS1 silencing attenuated BC cell proliferation, migration, and invasion in vitro, and reduced tumor growth in xenograft models. Furthermore, RHPN1-AS1 silencing was associated with a decrease in the expression of epithelial-to-mesenchymal transition (EMT) markers in the xenograft tumors, suggesting that RHPN1-AS1 promotes invasion in BC cells by enhancing EMT. These findings suggest that RHPN1-AS1 is a potential prognostic biomarker and therapeutic target for BC.

SNHG14 confers gefitinib resistance in non-small cell lung cancer by up-regulating ABCB1 via sponging miR-206-3p

Gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has been widely used as a first-line agent in EGFR-mutant non-small cell lung cancer (NSCLC). Nevertheless, the development of chemoresistance ultimately limited the curative effect of anti-cancer drugs. The present study aims to investigate the functions of SNHG14 in gefitinib resistance and gain insight into the underlying molecular mechanisms. In the present study, we found that SNHG14 expression was elevated and miR-206-3p expression was decreased in gefitinib-resistant NSCLC tumor tissues and cells. Functionally, SNHG14 overexpression increased gefitinib resistance by promoting cell viability, lowering apoptosis and enhancing colony forming ability, while SNHG14 knockdown reduced gefitinib resistance in NSCLC cells. Mechanistically, SNHG14 induced ABCB1 expression via interaction with miR-206-3p. Moreover, depletion of SNHG14 enhanced the sensitivity of NSCLC cells to gefitinib in vivo. Together, SNHG14 confers gefitinib resistance in NSCLC by regulating miR-206-3p/ABCB1 pathway, contributing to a better understanding of SNHG14 in acquired resistance and elucidating a candidate target to improve treatment response of NSCLC patients.

Long Noncoding RNA LINC00460 Promotes the Gefitinib Resistance of Nonsmall Cell Lung Cancer Through Epidermal Growth Factor Receptor by Sponging miR-769-5p

The vital roles of long noncoding RNAs (lncRNAs) in the nonsmall cell lung cancer (NSCLC) tumorigenesis are increasingly important. This work aims to investigate the role of lncRNA LINC00460 in the gefitinib resistance of NSCLC cells and discover its relevant mechanism. Our finding reveals that the expression of lncRNA LINC00460 is upregulated in the gefitinib-resistant NSCLC tissue and cells, and closely correlated with advanced tumor stage and clinical poor prognosis outcome. Gain and loss functional assays are performed in gefitinib-resistant NSCLC cells (A549/GR), stating that LINC00460 facilitates the 50% inhibitive concentration of gefitinib for NSCLC cells, multidrug-resistant-related proteins (P-gp, MRP1, and BCRP), as well as the invasion. In vivo, LINC00460 silencing represses the tumor growth. Bioinformatics prediction tools and luciferase analysis confirm that the upregulated LINC00460 sponged miR-769-5p in NSCLC cells; moreover, epidermal growth factor receptor (EGFR) is identified as a direct target gene of miR-769-5p. Verification experiments confirm that the restoration of EGFR could weaken the sensibility of NSCLC cells toward the gefitinib. In conclusion, our result demonstrates that LINC00460 plays a pivotal role in gefitinib resistance of NSCLC cells by targeting EGFR through sponging miR-769-5p. This finding might serve as a therapeutic target for NSCLC.