Long Intervening Noncoding 00467 RNA Contributes to Tumorigenesis by Acting as a Competing Endogenous RNA against miR-107 in Cervical Cancer Cells

A review on the role of LINC00467 in the carcinogenesis

LINC00467 is an example of long intergenic non-coding RNAs whose roles in human disorders are being identified. This gene coding LINC00467 is located on chromosome 1: 211,382,736 - 211,435,570 forward strand. This lncRNA has been firstly recognized through a microarray-based lncRNA profiling as an N-Myc target in neuroblastoma cells. Further studies have shown up-regulation of LINC00467 in different cancer including those originated from brain, gastrointestinal tract, lung and breast. It acts as a molecular sponge for miR-339, miR-138-5p, miR-107, miR-133b, miR-451a, miR-485-5p, miR-7-5p, miR-485-5p, miR-339-3p, miR-200a, miR-1285-3p, miR-299-5p, miR-509-3p, miR-18a-5p, miR-9-5p and miR-20b-5p. LINC00467 can regulate activity of NF-κB, STAT1, Wnt/b-catenin, Akt and ERK1/2 signaling pathways. Accumulating evidence indicates oncogenic role of LINC00467. The current review article aims at providing an overview of LINC00467 in the carcinogenesis.

LINC00467: an oncogenic long noncoding RNA

Long non-coding RNAs (lncRNAs) have been found to play essential roles in the cell proliferation, fission and differentiation, involving various processes in humans. Recently, there is more and more interest in exploring the relationship between lncRNAs and tumors. Many latest evidences revealed that LINC00467, an oncogenic lncRNA, is highly expressed in lung cancer, gastric cancer, colorectal cancer, hepatocellular carcinoma, breast cancer, glioblastoma, head and neck squamous cell carcinoma, osteosarcoma, and other malignant tumors. Besides, LINC00467 expression was linked with proliferation, migration, invasion and apoptosis via the regulation of target genes and multiple potential pathways. We reviewed the existing data on the expression, downstream targets, molecular mechanisms, functions, relevant signaling pathways, and clinical implications of LINC00467 in various cancers. LINC00467 may serve as a novel biomarker or therapeutic target for the diagnosis and prognosis of various human tumors.

LINC00467: A key oncogenic long non-coding RNA

The significance of long non-coding RNAs (lncRNAs) in the development and progression of human cancers has attracted increasing attention in recent years of investigations. Having versatile interactions and diverse functions, lncRNAs can act as oncogenes or tumor-suppressors to actively regulate cell proliferation, survival, stemness, drug resistance, invasion and metastasis. LINC00467, an oncogenic member of long intergenic non-coding RNAs, is upregulated in numerous malignancies and its high expression is often related to poor clinicopathological features. LINC00467 facilitates the progression of cancer via sponging tumor-suppressive microRNAs, inhibiting cell death cascade, modulating cell cycle controllers, and regulating signalling pathways including AKT, STAT3, NF-κB and Wnt/β-catenin. A growing number of studies have revealed that LINC00467 may serve as a novel prognostic biomarker and its inhibitory targeting has a valuable therapeutic potential to suppress the malignant phenotypes of cancer cells. In the present review, we discuss the importance of LINC00467 and provide a comprehensive collection of its functions and molecular mechanisms in a variety of cancer types.

Long Noncoding RNA LINC00467: Role in Various Human Cancers

Intricate genetic mutations promote the progression of different cancer types. Long noncoding RNAs (lncRNAs) have been widely demonstrated to participate in the genomic activities of various human cancers. Long intergenic non-coding RNA 467 (LINC00467) is an upregulated lncRNA in diverse diseases, especially in several types of cancers. Functional experiments of LINC00467 revealed that LINC00467 overexpression enhanced cell chemoresistance, proliferation, migration, and invasion in several types of cancers. Moreover, overexpressed LINC00467 was associated with a poor clinical prognosis. The present evidence suggests that LINC00467 may serve as a promising prognostic indicator and become a novel cancer therapeutic target. In this review, we introduce the biologic functions of lncRNAs and describe the molecular mechanism and clinical significance of LINC00467 in detail.

Long intergenic non-protein coding RNA 467 inhibition elevates microRNA-27b-3p to repress malignant behaviors of gastric cancer cells via reducing STAT3

Emerging evidence indicated that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) exert critical effects on tumorigenesis of multiple malignancies, including gastric cancer (GC). We aim to explore the effects of long intergenic non-protein coding RNA 467 (LINC00467) and miR-27b-3p on GC. GC cells were initially cultured. LINC00467, miR-27b-3p, and signal transducer and activator of transcription 3 (STAT3) expression in GC were detected. The altered LINC00467 and/or miR-27b-3p were transfected into screened cells. Then, the biological activities of GC cells and the tumor growth in vivo were examined. The binding relationships among LINC00467, miR-27b-3p, and STAT3 were confirmed. It was indicated that LINC00467 was increased while miR-27b-3p was decreased in GC tissues and cells. Inhibition of LINC00467 hindered GC cell malignancy and blocked tumor development by upregulating miR-27b-3p. LINC00467 sponged miR-27b-3p and STAT3 was targeted by miR-27b-3p. It was discovered that LINC00467 reduction upregulates miR-27b-3p to repress malignant GC cell growth via inhibiting STAT3. This research may deepen the insight of molecular mechanisms on GC.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

E2F transcription factor 1 elevates cyclin D1 expression by suppressing transcription of microRNA-107 to augment progression of glioma

BACKGROUND

Dysregulation of microRNAs has been frequently implicated in the progression of human diseases, including glioma. This study aims to explore the interaction between E2F transcription factor 1 (E2F1) and miR-107 in the progression of glioma.

METHODS

Expression of miR-107 in glioma tissues and cells was examined. Putative binding sites between E2F1 and the promoter region of miR-107, and between miR-107 and cyclin D1 (CCND1) mRNA were predicted via bioinformatic systems and validated via chromatin immunoprecipitation and luciferase reporter gene assays. Altered expression of miR-107, E2F1, and CCND1 was introduced in A172 and T98G cells to examine their roles in cell growth and the activity of the Wnt/β-catenin signaling. In vivo experiments were performed by injecting cells in nude mice.

RESULTS

miR-107 was poorly expressed, whereas E2F1 and CCND1 were highly expressed in glioma tissues and cells. E2F1 bound to the promoter region of miR-107 to induce transcriptional repression, and miR-107 directly bound to CCND1 mRNA to reduce its expression. Overexpression of miR-107 reduced proliferation, migration and invasion, and augmented apoptosis of glioma cells, and it reduced activity of the Wnt/β-catenin pathway. The anti-tumorigenic roles of miR-107 were blocked by E2F1 or CCND1 overexpression. Similar results were reproduced in vivo where miR-107 overexpression or E2F1 inhibition blocked tumor growth in nude mice.

CONCLUSION

This study suggested that E2F1 reduces miR-107 transcription to induce CCND1 upregulation, which leads to progression of glioma via Wnt/β-catenin signaling activation.

Linc00467 promotion of gastric cancer development by directly regulating miR-7-5p expression and downstream epidermal growth factor receptor

Linc00467 is a vital regulator in tumor progression. This study explores the molecular mechanisms of linc00467 in gastric cancer (GC). Linc00467 expression was obtained and analyzed in GC tissue through exploration in the cancer genome atlas database. Then, real-time quantitative polymerase chain reaction was used to detect linc000467 expression in GC cells. Cell functions were observed using cell counting Kit-8, Transwell assay, Western blotting to testify the proliferation, migration, invasion, and the relative expression of epidermal growth factor receptor (EGFR) in GC cells. Moreover, a dual-luciferase reporter gene assay was used to verify the relationship between linc00467 and miR-7-5p. Results showed that the expression of linc00467 was overexpressed in GC. Linc00467 silencing decreased the GC cell proliferation, migration, and invasion. With mRNA verification and combined previous research, linc00467 directly regulated the miR-7-5p expression and downstream EGFR expression. Inhibited miR-7-5p could restore cell function, EGFR expression of GC cells when linc00467 knockdown occurs. Altogether, linc00467 directly regulates the miR-7-5p and EGFR signaling pathway to promote GC proliferation, migration, and invasion.

Overexpressed LINC00467 promotes the viability and proliferation yet inhibits apoptosis of gastric cancer cells via raising ITGB3 level

Long non-coding RNA (lncRNA) LINC00467 plays a proto-oncogenic role in non-small cell lung cancer. However, its effect and modulatory mechanism in gastric cancer (GC) are unknown. Thereby, we elucidated the mechanism of LINC00467 in GC. LINC00467 level in GC tissues was assessed by bioinformatic analysis, and clinicopathological parameters from GC patients were collected. The levels of LINC00467, integrin subunit beta 3 (ITGB3), proliferating cell nuclear antigen (PCNA), cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase 1 (PARP1) in tissue samples or treated GC cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), or Western blot. The viability, proliferation and apoptosis of GC cells were detected by methyl thiazolyl tetrazolium assay, colony formation assay, and flow cytometry. Levels of LINC00467 and ITGB3 were up-regulated in GC, and highly expressed LINC00467 was positively associated with tumor size, differentiation, N stage, and T stage in GC patients. LINC00467 was enriched in cytoplasm of GC cells, and overexpressed LINC00467 promoted the viability and proliferation as well as levels of ITGB3 and PCNA, while suppressing the apoptosis and levels of cleaved caspase-3 and cleaved PARP1 in GC cells. Besides, the effects of shLINC00467 on inhibiting cell viability, proliferation of GC cells and PCNA level and promoting apoptosis as well as levels of cleaved caspase-3 and cleaved PARP1 were all partially reversed by overexpressed ITGB3. Overexpressed LINC00467 enhanced the viability and proliferation but inhibited apoptosis of GC cells via increasing ITGB3 level.

The Biological Significance of Long noncoding RNAs Dysregulation and their Mechanism of Regulating Signaling Pathways in Cervical Cancer

Despite the remarkable decrease in cervical cancer incidence due to the availability of the HPV vaccine and implementation of screening programs for early detection in developed countries, this cancer remains a major health problem globally, especially in developing countries where most of the cases and mortality occur. Therefore, more understanding of molecular mechanisms of cervical cancer development might lead to the discovery of more effective diagnosis and treatment options. Research on long noncoding RNAs (lncRNAs) demonstrates the important roles of these molecules in many physiological processes and diseases, especially cancer. In the present review, we discussed the significance of lncRNAs altered expression in cervical cancer, highlighting their roles in regulating highly conserved signaling pathways, such as mitogen-activated protein kinase (MAPK), Wnt/β-catenin, Notch, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways and their association with the progression of cervical cancer in order to bring more insight and understanding of this disease and their potential implications in cancer diagnosis and therapy.

Reduced LINC00467 elevates microRNA-125a-3p to suppress cisplatin resistance in non-small cell lung cancer through inhibiting sirtuin 6 and inactivating the ERK1/2 signaling pathway

OBJECTIVE

The non-coding RNAs have been identified as potential biomarkers in cancers. This study aimed to investigate the effect of long intergenic non-protein coding RNA 467 (LINC00467)/microRNA (miR-125a-3p)/sirtuin 6 (SIRT6) axis on non-small cell lung cancer (NSCLC).

METHODS

Expression of LINC00467, miR-125a-3p, SIRT6, and ERK1/2 signaling pathway-related factor in NSCLC was assessed. A549 and H1299 cells were induced by cisplatin (DDP) to establish DDP-resistant cell lines, and the drug resistance was detected. DDP-resistant cells were transfected with relative oligonucleotides and/or plasmids to observe the effects of LINC00467 and miR-125a-3p on NSCLC cells. The interaction among LINC00467, miR-125a-3p, and SIRT6 was detected using dual luciferase reporter gene assay and RNA pull-down assay. A tumor xenograft model was established, and Ki67 expression was detected in tumors.

RESULTS

LINC00467 and SIRT6 were upregulated, miR-125a-3p was suppressed, and the ERK1/2 pathway was activated in NSCLC. LINC00467 or SIRT6 inhibition or miR-125a-3p elevation restricted malignancy and DDP resistance of NSCLC cells. Reduced miR-125a-3p reversed the effect of inhibited LINC00467 on NSCLC cells. LINC00467 competitively bound to miR-125a-3p, and miR-125a-3p targeted SIRT6. Inhibiting LINC00467 and SIRT6 or upregulating miR-125a-3p repressed tumor formation in vivo.

CONCLUSION

LINC00467 silencing upregulates miR-125a-3p to decrease DDP resistance in NSCLC cells via inhibiting SIRT6 and inactivating the ERK1/2 signaling pathway.

Competing Endogenous RNAs in Cervical Carcinogenesis: A New Layer of Complexity

MicroRNAs (miRNAs) regulate gene expression by binding to complementary sequences within target mRNAs. Apart from working ‘solo’, miRNAs may interact in important molecular networks such as competing endogenous RNA (ceRNA) axes. By competing for a limited pool of miRNAs, transcripts such as long noncoding RNAs (lncRNAs) and mRNAs can regulate each other, fine-tuning gene expression. Several ceRNA networks led by different lncRNAs—described here as lncRNA-mediated ceRNAs—seem to play essential roles in cervical cancer (CC). By conducting an extensive search, we summarized networks involved in CC, highlighting the major impacts of such dynamic molecular changes over multiple cellular processes. Through the sponging of distinct miRNAs, some lncRNAs as HOTAIR, MALAT1, NEAT1, OIP5-AS1, and XIST trigger crucial molecular changes, ultimately increasing cell proliferation, migration, invasion, and inhibiting apoptosis. Likewise, several lncRNAs seem to be a sponge for important tumor-suppressive miRNAs (as miR-140-5p, miR-143-3p, miR-148a-3p, and miR-206), impairing such molecules from exerting a negative post-transcriptional regulation over target mRNAs. Curiously, some of the involved mRNAs code for important proteins such as PTEN, ROCK1, and MAPK1, known to modulate cell growth, proliferation, apoptosis, and adhesion in CC. Overall, we highlight important lncRNA-mediated functional interactions occurring in cervical cells and their closely related impact on cervical carcinogenesis.

LncRNA EPB41L4A-AS2 represses Nasopharyngeal Carcinoma Metastasis by binding to YBX1 in the Nucleus and Sponging MiR-107 in the Cytoplasm

Nasopharyngeal carcinoma (NPC) is known for its potential to progress to the lymph nodes and distant metastases at an early stage. As an important regulator in tumorigenesis biological processes, the functions of lncRNA in NPC tumor development remain largely unclear. In this research, the expression of EPB41L4A-AS2 in NPC tissues and cells was analyzed via real-time quantitative polymerase chain reaction (qRT-PCR). CCK8, colony formation, and EDU experiments were used to determine the viability of NPC cells. Transwell and wound healing assays were performed to test NPC cell migration and invasion. RNA pull-down and mass spectrometry analysis were used to identify potential binding proteins. Then, a popliteal lymph node metastasis model was established to test NPC metastasis. EPB41L4A-AS2 is repressed by transforming growth factor-beta, which is downregulated in NPC cells and tissue. It is associated with the presence of distant metastasis and adverse outcomes. The univariate and multivariate survival assays confirmed that EPB41L4A-AS2 expression was an independent predictor of progression-free survival (PFS) in patients with NPC. Biological analyses showed that overexpression of EPB41L4A-AS2 reduced the metastasis and invasion of NPC in vitro and in vivo, but had no significant effect on cell proliferation. Mechanistically, in the nucleus we identified that EPB41L4A-AS2 relies on binding to YBX1 to reduce the stability of Snail mRNA to enhance the expression of E-cadherin and reverse the progression of epithelial-to-mesenchymal transition (EMT). In the cytoplasm, we found that EPB41L4A-AS2 blocked the invasion and migration of NPC cells by promoting LATS2 expression via sponging miR-107. In a whole, the findings of this study help to further understand the metastasis mechanism of NPC and could help in the prevention and treatment of NPC metastasis.

LINC00467 facilitates osteosarcoma progression by sponging miR‑217 to regulate KPNA4 expression

Osteosarcoma (OS) is a musculoskeletal malignancy that originates from interstitial cells. An increasing number of studies have verified that long non-coding RNAs (lncRNAs) participate in the progression of numerous types of cancer. It has been reported that LINC00467 is a cancer-promoting gene in some types of cancer; however, the regulatory mechanism of LINC00467 in OS remains unknown. In the present study, reverse transcription-quantitative PCR was used to determine LINC00467 expression in OS tissues and cells. Additionally, the impact of LINC00467-knockdown on OS cell proliferation, migration and invasion was analyzed using Cell Counting Kit-8, colony formation and Transwell assays, as well as western blot analysis. RNA pulldown and luciferase reporter assays were conducted to investigate the regulatory mechanism of LINC00467 in OS. The results delineated that LINC00467 expression was elevated in OS tissues and cells, and that high LINC00467 expression was associated with a poor prognosis in patients with OS. LINC00467 inhibition suppressed OS progression by inhibiting cell proliferation, migration, invasion and epithelial-mesenchymal transition. LINC00467 served as a molecular sponge for microRNA (miR)-217, while karyopherin subunit α4 (KPNA4) was a downstream target gene of miR-217. Moreover, the overexpression of KPNA4 reversed the inhibitory effects of LINC00467 inhibition on OS progression. Therefore, the present study elucidated the potential mechanism of LINC00467 in OS and indicated that LINC00467 exerted its carcinogenic effects on OS through the miR-217/KPNA4 axis, implying that LINC00467 may be a novel potential therapeutic target for OS.

LINC00467 knockdown repressed cell proliferation but stimulated cell apoptosis in glioblastoma via miR-339-3p/IP6K2 axis

BACKGROUND

Glioma is considered to be one of the most common and lethal malignant brain tumors, accounting for 40% to 50% of brain tumors. Long non-coding RNAs (lncRNAs) have been widely proved to play an irreplaceable role in the tumorigenesis and progression. Nevertheless, the role of LINC00467 in glioblastoma remained unclear.

AIM

The current study was aimed to explore the functional mechanism of LINC00467 in glioblastoma.

METHODS

The expression of LINC00467/miR-339-3p/IP6K2 glioblastoma tissues and cells was evaluated by RT-qPCR. The protein expression of genes (cleaved PARP, PARP, cleaved caspase 3, caspase 3, Bax, Bcl-2 and IP6K2) was measured by western blot assay. Then role of LINC00467 was demonstrated by EdU, colony formation, flow cytometry and TUNEL assays. The relationship between miR-339-3p and LINC00467/IP6K2 was validated by RNA pull down and luciferase reporter assays.

RESULTS

The expression of LINC00467 was upregulated in glioblastoma tissues and cells. LINC00467 knockdown suppressed cell proliferation but activated cell apoptosis. Further, LINC00467 high expression was associated with shorter overall survival rate in glioblastoma patients. Further, LINC00467 could bind with miR-339-3p, and IP6K2 was targeted by miR-339-3p. IP6K2 expression was regulated by LINC00467/miR-339-3p in a ceRNA pattern. Moreover, LINC00467 could regulate the development of glioblastoma via miR-339-3p/IP6K2 axis.

CONCLUSIONS

LINC00467 knockdown repressed cell proliferation but stimulated cell apoptosis in glioblastoma via miR-339-3p/IP6K2 axis, which may enlighten to find a novel therapeutic tactic for glioblastoma patients.

LINC00467 Is Upregulated by DNA Copy Number Amplification and Hypomethylation and Shows ceRNA Potential in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common histological lung cancer, and it is the leading cause of cancer-related deaths worldwide. Long noncoding RNAs (lncRNAs) have been implicated in tumorigenesis. LINC00467 is a novel lncRNA that is abnormally expressed in several cancer types including LUAD. However, its function and regulatory mechanism in LUAD progression remain unclear. In this study, based on The Cancer Genome Atlas data mining, we demonstrated that DNA copy number amplification and hypomethylation was positively correlated with LINC00467 expression in LUAD. In addition, DNA copy number amplification was significantly associated with distant metastasis, immune infiltration and poor survival. Microarray analysis demonstrated that LINC00467 knockdown in the LUAD A549 cell line led to a distinct microRNA expression profile that impacted various target genes involved in multiple biological processes. This finding suggests that LINC00467 may regulate LUAD progression by functioning as a competing endogenous RNA (ceRNA). Finally, we constructed a ceRNA network that included two microRNAs (hsa-miR-1225-5p, hsa-miR-575) and five mRNAs (BARX2, BCL9, KCNK1, KIAA1324, TMEM182) specific to LINC00467 in LUAD. Subsequent Kaplan-Meier survival analysis in both The Cancer Genome Atlas and Gene Expression Omnibus databases revealed that two genes, BARX2 and BCL9, were potential prognostic biomarkers for LUAD patients. In conclusion, our data provide possible mechanisms underlying the abnormal upregulation of LINC00467 as well as a comprehensive view of the LINC00467-mediated ceRNA network in LUAD, thereby highlighting its potential role in diagnosis and therapy.

Long noncoding RNA LINC00467 facilitates the progression of acute myeloid leukemia by targeting the miR-339/SKI pathway

A growing body of evidence indicates that long non-coding RNA (lncRNA) is involved in the development and progression of many diseases. It has been reported that lncRNA LINC00467 is disregulated in multiple tumors, while its role in acute myeloid leukemia (AML) is still unknown. Here, we find that LINC00467 expression is significantly increased in AML specimens and cell lines. Further investigations show that knockdown of LINC00467 inhibits the malignant phenotypes of AML cells. Consistently, LINC00467 knockdown slows AML progression in immunodeficient mice. Interestingly, microRNA-339 (miR-339) is upregulated and its target gene SKI, an oncogene, is downregulated in AML cells after LINC00467 knockdown. More importantly, inhibition of miR-339 can largely abolish the effect of LINC00467 knockdown on AML cells. Collectively, our data demonstrate that LINC00467 plays an important role in the pathogenesis of AML by targeting the miR-339/SKI pathway, which provides a new sight for the subsequent treatment of AML.

[Expression of long non-coding RNA linc00467 in childhood acute myeloid leukemia and its role in drug resistance]

OBJECTIVE

To study the expression and function of long non-coding RNA linc00467 in childhood acute myeloid leukemia (AML).

METHODS

Bone marrow samples were collected from 5 children with AML who were diagnosed from May 2016 to June 2018. Normal bone marrow samples based on bone marrow examination were collected from 3 children as controls. Quantitative real-time PCR was used to measure the expression of linc00467 in the two groups. A lentivirus system was used to achieve overexpression of linc00467 in AML cells (HL-60) (linc00467 overexpression group), and empty vector expressing green fluorescent protein (GFP) was transfected into AML cells to establish a GFP control group. A lentivirus system was used to insert an interfering sequence into AML cells (sh-linc00467 interfering group), and a random sequence was inserted to establish an sh-NC control group. Cell proliferation and resistance to doxorubicin were observed for all groups.

RESULTS

Compared with the normal control group, the children with AML had a significant increase in linc00467 (P=0.018). Overexpression and interference with linc00467 expression had no significant effect on cell proliferation. Compared with the GFP control group, the linc00467 overexpression group had a significant increase in the viability of HL-60 cells at the adriamycin concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 μg/mL (P<0.05). Compared with the sh-NC control group, the sh-linc00467 interfering group had a significant reduction in the viability of HL-60 cells at the adriamycin concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 μg/mL (P<0.05). Compared with the untreated group, the adriamycin treatment group had a significant increase in the expression of linc00467 in HL-60 cells (P<0.05).

CONCLUSIONS

This study reveals the biological function of linc00467 to promote the resistance to adriamycin in AML, which provides a basis for developing new therapeutic drugs for AML.

Long noncoding RNA LINC00173 is downregulated in cervical cancer and inhibits cell proliferation and invasion by modulating the miR-182-5p/FBXW7 axis

Accumulating evidence has supported the concept that long noncoding RNAs (lncRNAs) participate in the initiation and progression of human cervical cancer (CC). The long intergenic nonprotein-coding RNA 173 (LINC00173) is a recently identified cancer-associated factor. However, the expression and biological role of LINC00173 in CC are poorly understood. Here, for the first time, we found that the expression of LINC00173 was decreased in CC tissues compared with that in nontumor tissues. Data from The Cancer Genome Atlas (TCGA) further revealed that the downregulated expression of LINC00173 in CC tissues was correlated with poor survival. Functionally, LINC00173 overexpression suppressed HeLa cell proliferation via induction of G0/G1 phase arrest. Ectopic expression of LINC00173 also repressed the invasiveness of HeLa cells. Conversely, LINC00173 depletion resulted in the enhanced proliferation and invasiveness of C33A cells. Mechanistically, LINC00173 functioned as a molecular sponge for miR-182-5p and inversely regulated the miR-182-5p level in CC cells. F-box and WD repeat domain-containing 7 (FBXW7) was identified as the target of miR-182-5p. LINC00173 overexpression enhanced the FBXW7 level via regulation of miR-182-5p in HeLa Cells. More importantly, the inhibitory effects of LINC00173 on HeLa cell proliferation and invasiveness were reversed by FBXW7 silencing. Taken together, the results indicate that the LINC00173/miR-182-5p/FBXW7 axis is critical for CC progression, which might offer new insights into effective therapy for CC.

The HOTAIRM1/miR-107/TDG axis regulates papillary thyroid cancer cell proliferation and invasion

The long noncoding RNA (lncRNA), HOX antisense intergenic RNA myeloid 1 (HOTAIRM1), has been shown to act as a tumor suppressor in various human cancers. However, the overall biological roles and clinical significance of HOTAIRM1 in papillary thyroid cancer (PTC) have not been investigated. In this study, we used quantitative reverse transcription PCR (qRT-PCR) to show that HOTAIRM1 was significantly downregulated in PTC tissues and low HOTAIRM1 expression levels were associated with lymph node metastasis and advanced TNM stage. We performed Cell Counting Kit-8, plate colony-formation, flow cytometric apoptosis, transwell, and scratch wound healing assays. Overexpression of HOTAIRM1 was found to inhibit PTC cell proliferation, invasion, and migration in vitro. Additionally, we identified miR-107 as a target of HOTAIRM1 using online bioinformatics tools. Dual-luciferase reporter gene and RNA immunoprecipitation assays were used to confirm that HOTAIRM1 acted as a competing endogenous RNA of miR-107. Furthermore, enhancement of miR-107 could potentially reverse the effects of HOTAIRM1 overexpression in vitro. Inhibition of miR-107 suppressed PTC cell proliferation, invasion, and migration in vitro. HOTAIRM1 overexpression and miR-107 inhibition impaired tumorigenesis in vivo in mouse xenografts. Bioinformatics prediction and a dual-luciferase reporter gene assay demonstrated the binding between miR-107 and the 3'-untranslated region of TDG. The results of qRT-PCR and western blotting assays suggested that HOTAIRM1 could regulate the expression of TDG in an miR-107-meditated manner. In conclusion, we validated HOTAIRM1 as a novel tumor-suppressor lncRNA in PTC and proposed that the HOTAIRM1/miR-107/TDG axis may serve as a therapeutic target for PTC.