Long Intergenic Non-Protein Coding RNA 665 Regulates Viability, Apoptosis, and Autophagy via the MiR-186-5p/MAP4K3 Axis in Hepatocellular Carcinoma

LncRNA ANRIL Promotes Glucose Metabolism and Proliferation of Colon Cancer in a High-Glucose Environment and is Associated with Worse Outcome in Diabetic Colon Cancer Patients

BACKGROUND

The potential involvement of type 2 diabetes mellitus (T2DM) as a risk factor for colon cancer (CC) has been previously reported. Epigenetic changes, such as deregulation of long non-coding RNA (lncRNA) and microRNA (miR), have been linked to the advancement of CC; however, the effects of high glucose levels on their deregulation and, in turn, colon cancer remain unexplored.

METHODS

Fifty patients had a dual diagnosis of CC and T2DM, and 60 patients with CC without diabetes mellitus were included in the study. qRT-PCR was used to examine the expression of lncRNA ANRIL and miR-186-5p in tissue samples. ANRIL, miR-186-5p, and their downstream target genes HIF-1α, PFK, HK, Bcl-2, and Bax were also determined in CC cell lines under various glucose conditions. Glucose uptake, lactate production and cells proliferation were estimated in CC cell lines.

RESULTS

A significant upregulation of ANRIL expression levels (p<0.001) and a significant downregulation of miR-186-5p expression (p<0.001) in diabetic colon cancer specimens compared to those in non-diabetic colon cancer group were observed. MiR-186-5p expression levels were inversely correlated with ANRIL expression levels, blood glucose levels and HbA1c%. Concerning in vitro model, a significant upregulation of ANRIL, downregulation of miR-186-5p, upregulation of HIF-1α, glycolytic enzymes and activation of antiapoptotic pathway was detected in higher glucose concentrations than lower one. There was a significant increase of glucose uptake, lactate accumulation and proliferation of the Caco2 and SW620 cell lines in a dose dependent manner of glucose concentrations. Moreover, a significant positive correlation between glucose uptake and ANRIL expression was shown.

CONCLUSIONS

A high-glucose environment can increase the tumor-promoting effect of ANRIL. ANRIL can promote glucose metabolism and colon cancer proliferation by downregulating miR-186-5p with subsequent upregulation of glycolysis enzymes expression and inhibition of apoptosis.

MiR-186-5p prevents hepatocellular carcinoma progression by targeting methyltransferase-like 3 that regulates m6A-mediated stabilization of follistatin-like 5

Background

Hepatocellular carcinoma (HCC) is a multistep process involving sophisticated genetic, epigenetic, and transcriptional changes. However, studies on microRNA (miRNA)'s regulatory effects of N6-methyladenosine (m6A) modifications on HCC progression are limited.

Methods

Cell Counting Kit-8 (CCK-8), clone formation, and Transwell assays were used to investigate changes in cancer cell proliferation, invasion, and migration. RNA m6A levels were verified using methylated RNA immunoprecipitation. Luciferase reporter assay was used to study the potential binding between miRNAs and mRNA. A mouse tumor transplant model was established to study the changes in tumor progression.

Results

Follistatin-like 5 (FSTL5) was significantly downregulated in HCC and inhibited its further progression. Additionally, methyltransferase-like 3 (METTL3) reduced FSTL5 mRNA stability in an m6A-YTH domain family 2(YTHDF2)-dependent manner. Functional experiments revealed that METTL3 downregulation inhibited HCC progression by upregulating FSTL5 in vitro and in vivo. Luciferase reporter assay verified that miR-186-5p directly targets METTL3. Additionally, miR-186-5p inhibits the proliferation, migration, and invasion of HCC cells by downregulating METTL3 expression.

Conclusions

The miR-186-5p/METTL3/YTHDF2/FSTL5 axis may offer new directions for targeted HCC therapy.

Sufentanil Suppresses Cell Carcinogenesis Via Targeting miR-186-5p/HMGB1 Axis and Wnt/β-Catenin Pathway in Non-Small-Cell Lung Cancer

Sufentanil is a common opioid anesthetic agent, which exerts anti-cancer properties in several cancer types. However, its action mechanisms in non-small cell lung cancer (NSCLC) are unclear. Therefore, the present study investigated the pharmacological effect of sufentanil on miRNAs in NSCLC treatment. In this study, after treatment with sufentanil, the proliferation, migration, invasion and apoptosis of A549 and H1299 NSCLC cell lines were measured by cell counting kit-8 (CCK-8) assay, colony formation assay, transwell assays and flow cytometry. Quantitative real time polymerase chain reaction (qRT-PCR) was utilized to detect the expression of miR-186-5p and high mobility group box-1 (HMGB1), and their interaction was analyzed using luciferase reporter assay. The proteins of HMGB1, and apoptosis- and Wnt/β-catenin pathway-related factors were detected by western blot. It was demonstrated that sufentanil significantly upregulated miR‑186‑5p to restrict NSCLC cell proliferation, migration, invasion, and boost apoptosis in vitro. Mechanically, miR-186-5p interacted with HMGB1 and negatively regulated HMGB1 in NSCLC cells. Furthermore, rescue assay showed that sufentanil exerted antitumor activities by upregulating miR-186-5p, which targeted HMGB1 and restrained Wnt/β-catenin signal pathway in NSCLC cells. In conclusion, these results suggested that sufentanil disrupts the oncogenicity of NSCLC cells by regulating miR-186-5p/HMGB1/β-catenin axis, providing a promising implication for the anti-oncogenic effect of sufentanil.

LINC00665: A Promising Biomarker in Gastrointestinal Tumors

An increasing volume of studies has reported that long non-codingRNAs (lncRNAs) are involved in the carcinogenesis of many different cancers. Especially in gastrointestinal tumors, lncRNAs are found to participate in various physiological and pathological processes. LncRNAs can regulate gene expression at multiple levels, including transcriptional, post-transcription, translational, and post-translational levels. Long intergenic non-protein coding RNA 665(LINC00665), a novel cancer-related lncRNA, is frequently dysregulated in multiple gastrointestinal tumors, including gastric and colorectal cancers, hepatocellular carcinoma, and so on. In this review, we analyzed the expression and prognostic value of LINC00665 in human gastrointestinal tumors, systematically summarized the current literature about the clinical significance of this lncRNA, and explored the regulatory mechanisms of LINC00665 as a competing endogenous RNA (ceRNA) in tumor progression. Consequently, we concluded that LINC00665 might act as a prognostic biomarker and a potential target for gastrointestinal tumor diagnosis and treatment.

miR-186-ANXA9 signaling inhibits tumorigenesis in breast cancer

Breast cancer (BC) ranks as the highest incidence among cancer types in women all over the world. MicroRNAs (miRNAs) are a class of short endogenous non-coding RNA in cells mostly functioning to silence the target mRNAs. In the current study, a miRNA screening analysis identified miR-186-5p to be downregulated in human breast cancer tumors. Functional studies in vitro demonstrated that overexpression of miR-186-5p inhibited cellular proliferation and induced cell apoptosis in multiple breast cancer cell lines including MDA-MB-231, MCF-7, and BT549 cells. Transplantation of the miR-186-5p-overexpressing MDA-MB-231 cells into nude mice significantly inhibited mammary tumor growth in vivo. Sequence blast analysis predicted annexin A9 (ANXA9) as a target gene of miR-186-5p, which was validated by luciferase reporter assay, QRT-PCR analysis, and western blot. Additional gene expression analysis of clinical tumor samples indicated a negative correlation between miR-186-5p and ANXA9 in human breast cancer. Knockdown of ANXA9 mimicked the phenotype of miR-186-5p overexpression. Reintroduction of ANXA9 back rescued the miR-186-5p-induced cell apoptosis. In addition, miR-186-5p decreased the expression of Bcl-2 and increased the expression of p53, suggesting a mechanism regulating miR-186-5p-induced cellular apoptosis. In summary, our study is the first to demonstrate miR-186-5p-ANXA9 signaling in suppressing human breast cancer. It provided a potential therapeutic target in breast cancer.

Decoding hepatocarcinogenesis from a noncoding RNAs perspective

Being a leading lethal malignancy worldwide, the pathophysiology of hepatocellular carcinoma (HCC) has gained a lot of interest. Yet, underlying mechanistic basis of the liver tumorigenesis is poorly understood. The role of some coding genes and their respective translated proteins, then later on, some noncoding RNAs (ncRNAs) such as microRNAs have been extensively studied in context of HCC pathophysiology; however, the implication of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in HCC is indeed less investigated. As a subclass of the ncRNAs which has been elusive for long time ago, lncRNAs was found to be involved in plentiful cellular functions such as DNA, RNA, and proteins regulation. Hence, it is undisputed that lncRNAs dysregulation profoundly contributes to HCC via diverse etiologies. Accordingly, lncRNAs represent a hot research topic that requires prime focus in HCC. In this review, the authors discuss breakthrough discoveries involving lncRNAs and circRNAs dysregulation that have contributed to the contemporary concepts of HCC pathophysiology and how these concepts could be leveraged as potential novel diagnostic and prognostic HCC biomarkers. Further, this review article sheds light on future trends, thereby discussing the pathological roles of lncRNAs and circRNAs in HCC proliferation, migration, and epithelial-to-mesenchymal transition. Along this line of reasoning, future recommendations of how these targets could be exploited to achieve effective HCC-related drug development is highlighted.

Targeting and regulation of autophagy in hepatocellular carcinoma: revisiting the molecular interactions and mechanisms for new therapy approaches

Autophagy is an evolutionarily conserved process that plays a role in regulating homeostasis under physiological conditions. However, dysregulation of autophagy is observed in the development of human diseases, especially cancer. Autophagy has reciprocal functions in cancer and may be responsible for either survival or death. Hepatocellular carcinoma (HCC) is one of the most lethal and common malignancies of the liver, and smoking, infection, and alcohol consumption can lead to its development. Genetic mutations and alterations in molecular processes can exacerbate the progression of HCC. The function of autophagy in HCC is controversial and may be both tumor suppressive and tumor promoting. Activation of autophagy may affect apoptosis in HCC and is a regulator of proliferation and glucose metabolism. Induction of autophagy may promote tumor metastasis via induction of EMT. In addition, autophagy is a regulator of stem cell formation in HCC, and pro-survival autophagy leads to cancer cell resistance to chemotherapy and radiotherapy. Targeting autophagy impairs growth and metastasis in HCC and improves tumor cell response to therapy. Of note, a large number of signaling pathways such as STAT3, Wnt, miRNAs, lncRNAs, and circRNAs regulate autophagy in HCC. Moreover, regulation of autophagy (induction or inhibition) by antitumor agents could be suggested for effective treatment of HCC. In this paper, we comprehensively review the role and mechanisms of autophagy in HCC and discuss the potential benefit of targeting this process in the treatment of the cancer. Video Abstract.

LncRNA NUTM2A-AS1 aggravates the progression of hepatocellular carcinoma by activating the miR-186-5p/KLF7-mediated Wnt/beta-catenin pathway

Emerging evidence has uncovered that noncoding RNAs (ncRNAs) contribute to the development of hepatocellular carcinoma (HCC). Nevertheless, the functions of the majority of long ncRNAs (lncRNAs) in HCC are unknown. Here, we intend to probe the function of lncRNA NUTM2A-AS1 in the evolvement of HCC and the related mechanism. Expression levels of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 mRNA in HCC tissues and adjacent non-tumor tissues were monitored. Gain- or loss-of-function assays were utilized to investigate the biological functions of lncRNA NUTM2A-AS1, miR-186-5p and KLF7 in HCC cell lines (including HCCLM3 and Huh7). Western blot was implemented for the detection of the epithelial-mesenchymal transition (EMT)-related proteins (including E-cadherin, Vimentin and Snail), KLF7, Wnt, β-catenin, and stemness-related proteins (Nanog, OCT4, YKL40, and CD133). Furthermore, the targeted associations between lncRNA NUTM2A-AS1, miR-186-5p, and KLF7 were verified by bioinformatics analysis, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. As a result, lncRNA NUTM2A-AS1 and KLF7 profiles were heightened in the HCC tissues versus adjacent normal tissues, while miR-186-5p had the opposite expression tendency. Up-regulation of lncRNA NUTM2A-AS1 was related to tumor size, advanced tumor stage, and lymph node metastasis of HCC patients. Functionally, overexpression of lncRNA NUTM2A-AS1 heightened HCC cells' growth, invasion, EMT, and stemness and repressed their apoptosis by activating the Wnt/β-catenin pathway. In contrast, up-regulation of miR-186-5p or inhibition of KLF7 had reverse effects. In vivo, lncRNA NUTM2A-AS1 overexpression facilitated tumor growth and EMT, accompanied by declined miR-186-5p levels and enhanced KLF7 expression. The mechanistic studies revealed that miR-186-5p served as a common target of lncRNA NUTM2A-AS1 and KLF7. As hinted by the rescue experiments, NUTM2A-AS1 partly abated miR-186-5p-mediated anti-tumor effects in HCC cells, whereas KLF7 knockdown reversed the promotive effects of NUTM2A-AS1. LncRNA NUTM2A-AS1 accelerated the evolution of HCC by up-regulating the KLF7/Wnt/beta-catenin pathway through sponging miR-186-5p.

A Feedback Loop of LINC00665 and the Wnt Signaling Pathway Expedites Osteosarcoma Cell Proliferation, Invasion, and Epithelial-Mesenchymal Transition

OBJECTIVES

Osteosarcoma (OS) is a malignant tumor with frequent occurrence among teenagers. Long non-coding RNAs (lncRNAs) play pro-cancer roles in many tumors. The purpose of this study was to figure out the functional role of a novel lncRNA long intergenic non-protein coding RNA 665 (LINC00665) in OS by observing the OS cell behaviors.

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to analyze LINC00665 expression in OS cells. Cell function assays assessed the impacts of LINC00665 on OS cell phenotype. Immunofluorescence and western blot analyzed the function of LINC00665 on epithelial-mesenchymal transition (EMT) in OS. Moreover, mechanistic assays analyzed the downstream mechanism of LINC00665 in OS cells.

RESULTS

LINC00665 was significantly up-regulated in OS cells. LINC00665 silence facilitated OS cell proliferation, migration, invasion, and EMT while inhibiting cell apoptosis. Mechanically, LINC00665 acted as a competing endogenous RNA (ceRNA) to sponge miR-1249-5p and thereby modulated Wnt family member 2B (WNT2B) to activate Wnt pathway. Wnt pathway activated LINC00665 expression transcriptionally.

CONCLUSIONS

Our study uncovered the cancer-promoting role of LINC00665 in OS, and the feedback loop of LINC00665/miR-1249-5p/WNT2B/Wnt might be a potential target for OS treatment.

A Concise Review on Dysregulation of LINC00665 in Cancers

Long Intergenic Non-Protein Coding RNA 665 (LINC00665) is an RNA gene located on the minus strand of chromosome 19. This lncRNA acts as a competing endogenous RNA for miR-4458, miR-379-5p, miR-551b-5p, miR-3619-5p, miR-424-5p, miR-9-5p, miR-214-3p, miR-126-5p, miR-149-3p, miR-379-5p, miR-665, miR-34a-5p, miR-186-5p, miR-138-5p, miR-181c-5p, miR-98, miR-195-5p, miR-224-5p, miR-3619, miR-708, miR-101, miR-1224-5p, miR-34a-5p, and miR-142-5p. Via influencing expression of these miRNAs, it can enhance expression of a number of oncogenes. Moreover, LINC00665 can influence activity of Wnt/β-Catenin, TGF-β, MAPK1, NF-κB, ERK, and PI3K/AKT signaling. Function of this lncRNA has been assessed through gain-of-function tests and/or loss-of-function studies. Furthermore, diverse research groups have evaluated its expression levels in tissue samples using microarray and RT-qPCR techniques. In this manuscript, we have summarized the results of these studies and categorized them in three sections, i.e., cell line studies, animal studies, and investigations in clinical samples.

Hepatitis B Virus-Encoded HBsAg Contributes to Hepatocarcinogenesis by Inducing the Oncogenic Long Noncoding RNA LINC00665 through the NF-κB Pathway

Clinical and in vivo studies have demonstrated a role for hepatitis B virus (HBV)-encoded HBsAg (hepatitis B surface antigen) in HBV-related hepatocellular carcinoma (HCC); however, the underlying mechanisms remain largely unknown. Here, we investigated the role of HBsAg in regulating long noncoding RNAs (lncRNAs) involved in HCC progression. Our analysis of microarray data sets identified LINC00665 as an HBsAg-regulated lncRNA. Furthermore, LINC00665 is upregulated in liver samples from HBV-infected patients as well as in HCC, specifically in HBV-related HCC liver samples. These findings were supported by our in vitro data demonstrating that HBsAg, as well as HBV, positively regulates LINC00665 in multiple HBV cell culture models. Next, we evaluated the oncogenic potential of LINC00665 by its overexpression and CRISPR interference (CRISPRi)-based knockdown in various cell-based assays. LINC00665 promoted cell proliferation, migration, and colony formation but inhibited cell apoptosis in vitro. We then identified the underlying mechanism of HBsAg-mediated regulation of LINC00665. We used immunofluorescence assays to show that HBsAg enhanced the nuclear translocation of NF-κB factors in HepG2 cells, confirming that HBsAg activates NF-κB. Inhibition of NF-κB signaling nullified HBsAg-mediated LINC00665 upregulation, suggesting that HBsAg acts through NF-κB to regulate LINC00665. Furthermore, the LINC00665 promoter contains NF-κB binding sites, and their disruption abrogated HBsAg-induced LINC00665 upregulation. Finally, HBsAg facilitated the enrichment of the NF-κB factors NF-κB1, RelA, and c-Rel in the LINC00665 promoter. Taken together, this work shows that HBsAg can drive hepatocarcinogenesis by upregulating oncogenic LINC000665 through the NF-κB pathway, thereby identifying a novel mechanism in HBV-related HCC. IMPORTANCE Hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC). Numerous reports indicate an oncogenic role for HBV-encoded HBsAg; however, the underlying mechanisms are not well understood. Here, we studied the role of HBsAg in regulating lncRNAs involved in hepatocarcinogenesis. We demonstrate that HBsAg, as well as HBV, positively regulates oncogenic lncRNA LINC00665. The clinical significance of this lncRNA is highlighted by our observation that LINC00665 is upregulated in liver samples during HBV infection and HBV-related HCC. Furthermore, we show LINC00665 can drive hepatocarcinogenesis by promoting cell proliferation, colony formation, and cell migration and inhibiting apoptosis. Taken together, this work identified LINC00665 as a novel gene through which HBsAg can drive hepatocarcinogenesis. Finally, we show that HBsAg enhances LINC00665 levels in hepatocytes by activating the NF-κB pathway, thereby identifying a novel mechanism by which HBV may contribute to HCC.

Silencing LINC00665 inhibits cutaneous melanoma in vitro progression and induces apoptosis via the miR-339-3p/TUBB

Background

LncRNAs are closely related to cutaneous melanoma (CM) tumorigenesis and metastasis, and it can affect the progression of CM by regulating cell proliferation, migration, invasion, apoptosis, and other cellular mechanisms. This study investigated the role of LINC00665 in CM.

Methods

Expressions of LINC00665, miR‐339‐3p, and tubulin beta chain (TUBB) in CM cells were analyzed by qRT‐PCR and/or Western blot. The LINC00665/miR‐339‐3p/TUBB targeting network was predicted by bioinformatics tools, screened out by Venn diagrams and analyzed by Pearson's correlation coefficients, followed by validation via dual‐luciferase reporter assay and/or pull‐down assay. Transfection of siLINC00665 or miR‐339‐3p inhibitor/mimic was conducted with CM cells whose viability, proliferation, migration, invasion, cell cycle progression, and apoptosis were measured by CCK‐8 assay, colony formation assay, wound healing assay, Transwell assay, and flow cytometry. The associations of TUBB with tumor biological characteristics and other proteins were analyzed by CanserSEA and String, respectively.

Results

High‐expressed LINC00665 was detected in CM cells. Silencing LINC00665 decreased CM cell viability; inhibited colony formation, cell cycle progression, migration and invasion; enhanced apoptosis; and upregulated miR‐339‐3p. LINC00665 targeted miR‐339‐3p which targeted TUBB. MiR‐339‐3p upregulation induced effects similar to the LINC00665‐silencing‐induced effects and could downregulate TUBB, which was associated with malignant behaviors and related to other five proteins. MiR‐339‐3p downregulation induced the opposite effects of what miR‐339‐3p upregulation induced, and the miR‐339‐3p downregulation‐induced effects could be reversed by LINC00665 silencing.

Conclusion

Silencing LINC00665 inhibits in vitro CM progression and induces apoptosis via the miR‐339‐3p/TUBB axis.

The Biological and Molecular Function of LINC00665 in Human Cancers

Long non-coding RNAs (lncRNAs) are more than 200 nucleotides in length and are implicated in the development of human cancers, without protein-coding function. Mounting evidence indicates that cancer initiation and progression are triggered by lncRNA dysregulation. Recently, a growing number of studies have found that LINC00665, a long intergenic non-protein coding RNA, may be associated with various cancers, including gastrointestinal tumors, gynecological tumors, and respiratory neoplasms. LINC00665 was reported to be significantly dysregulated in cancers and has an important clinical association. It participates in cell proliferation, migration, invasion, and apoptosis through different biological pathways. In this review, we summarize the current findings on LINC00665, including its biological roles and molecular mechanisms in various cancers. LINC00665 may be a potential prognostic biomarker and novel therapeutic target for cancers.

LINC00665: An Emerging Biomarker for Cancer Diagnostics and Therapeutics

Long intergenic noncoding RNA 00665 (LINC00665) is located on human chromosome 19q13.12. LINC00665 was upregulated in eighteen cancers and downregulated in two cancers. LINC00665 not only inhibits 25 miRNAs but also directly affects the stability of ten protein-coding genes. Notably, LINC00665 also encodes a micro-peptide CIP2A-BP that promotes triple-negative breast cancer progression. LINC00665 can participate in five signaling pathways to regulate cancer progression, including the Wnt/β-catenin signaling pathway, TGF-β signaling pathway, NF-κB signaling pathway, PI3K/AKT signaling pathway, and MAPK signaling pathway. Aberrant expression of LINC00665 in breast cancer, gastric cancer, and hepatocellular carcinoma can be used for disease diagnosis. In addition, aberrant expression of LINC00665 is closely associated with clinicopathological features and poor prognosis of various cancers. LINC00665 is closely associated with the effects of anticancer drugs, including gefitinib and cisplatin in non-small cell lung cancer, gemcitabine in cholangiocarcinoma, and cisplatin-paclitaxel in breast cancer. This work systematically summarizes the diagnostic and prognostic values of LINC00665 in various tumors, and comprehensively analyzes the molecular regulatory mechanism related to LINC00665, which is expected to provide clear guidance for future research.

The Emerging Roles of LINC00665 in Human Cancers

Long non-coding RNAs (lncRNAs) are non-coding RNAs that have more than 200 nucleotides and can participate in the regulation of gene expression in various ways. An increasing number of studies have shown that the dysregulated expression of lncRNAs is related to the occurrence and progression of human cancers. LINC00665 is a novel lncRNA, which is abnormally expressed in various human cancers, such as lung cancer, breast cancer, prostate cancer, and glioma. LINC00665 functions in many biological processes of tumor cells, such as cell proliferation, migration, invasion, angiogenesis, and metabolism, and is related to the clinicopathological characteristics of cancer patients. LINC00665 can play biological functions as a ceRNA, directly binding and interacting with proteins, and as an upstream molecule regulating multiple signaling pathways. In this review, we comprehensively summarize the expression level, function, and molecular mechanisms of LINC00665 in different human cancers and emphasize that LINC00665 is a promising new diagnostic, prognostic biomarker, and therapeutic target.

AFAP1 antisense RNA 1 promotes retinoblastoma progression by sponging microRNA miR-545-3p that targets G protein subunit beta 1

The oncogenic role of actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) has been reported in retinoblastoma (RB). However, the underlying regulatory mechanisms remain poorly understood. In this study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting were performed to analyze the expression of AFAP1-AS1, microRNA miR-545-3p, or G protein subunit beta 1 (GNB1). Cell Counting Kit-8 (CCK-8) and Transwell migration assays were used to detect cell proliferation and migration. In addition, caspase-3 activity was monitored by caspase-3 activity assay. Luciferase reporter assays combined with RNA immunoprecipitation (RIP) and pull-down assays were performed to elucidate the target relationship between miR-545-3p and AFAP1-AS1 or GNB1. Xenograft tumor experiments were performed to evaluate RB cell growth in vivo. Increased AFAP1-AS1 and GNB1 expression in RB tissues and cells was confirmed by RT-qPCR; conversely, miR-545-3p was found to be downregulated in RB tissues and cells. AFAP1-AS1 overexpression resulted in increased proliferation and migration of RB cells, whereas AFAP1-AS1 silencing resulted in decreased proliferation and migration of RB cells. Moreover, AFAP1-AS1 was found to target miR-545-3p. The anti-miR-545-3p treatment phenocopied the effect of AFAP1-AS1 overexpression and promoted RB cell growth in vivo. miR-545-3p was found to directly target GNB1. GNB1 silencing resulted in reduced proliferation and migration of RB cells and attenuated the oncogenic effect of the miR-545-3p inhibitor. Thus, in this study, a novel ceRNA regulation network of AFAP1-AS1 in RB was identified, where AFAP1-AS1 regulated GNB1 expression by targeting miR-545-3p, ultimately driving RB progression.

LINC00665 sponges miR-641 to promote the progression of breast cancer by targeting the SNF2-related CREBBP activator protein (SRCAP)

The regulatory network of competing endogenous RNAs (ceRNA) exists widely in tumors and affects the expression of cancer-related genes, thus playing an important role in the development and prognosis of human tumors. In this research, we explored the role and mechanism of LINC00665 as a ceRNA in breast cancer. We analyzed the expression and targets of LINC00665 in breast cancer using bioinformatics, and detected their effects on breast cancer cells by CCK8, transwell, colony formation and flow cytometry assays. From our results, LINC00665 knockdown suppressed the proliferation, migration and invasion and induced the apoptosis through inactivating the AKT/mTOR signaling pathway in MCF7 and MDA-MB-231 cells. LINC00665 had five potential downstream target miRNAs (miR-542-3p, miR-624-5p, miR-641, miR-425-5p, and miR-30-3p). In dual-luciferase report gene assay, the fluorescence activity of cells transfected with miR-641 mimics decreased, and the expression of miR-641 decreased significantly after knocking down LINC00665. miR-641 mimics significantly inhibited cell proliferation and invasion in MCF7 and MDA-MB-231 cells. We detected five potential direct targets of miR-641 using qPCR (SRCAP, SIKE1, NADK, KHDC4, and HSPG2). SRCAP expression decreased significantly in miR-641 overexpression cells and the binding of SRCAP’s 3ʹUTR and miR-641 was further confirmed by dual-luciferase report gene assay. SRCAP blocked the proliferation and invasion inhibition induced by miR-641 or si-LINC00665 in MCF7 and MDA-MB-231 cells. In conclusion, LINC00665 could promote the survival and metastasis of breast cancer cells through sponging miR-641 and targeting SRCAP. This research provided new potential targets for targeted therapy in human breast cancer.

LINC00665 regulates hepatocellular carcinoma by modulating mRNA via the m6A enzyme

This study aimed to reveal the mechanism by which long noncoding RNAs (lncRNAs) modulate hepatocellular carcinoma (HCC) by regulating mRNA via the N6-methyladenosine (m6A) enzyme. The expression and clinical data of 365 HCC patients and 50 healthy control samples were downloaded from the the Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DElncRNAs) and differentially expressed mRNAs (DEmRNAs) screened using limma packages from the R. m6A2Target database were used to predict the relationship between m6A enzyme-lncRNA and m6A enzyme-mRNA. The mRNAs in the lncRNA-m6A enzyme-mRNA network were subjected to enrichment analysis. Cox regression analysis was used to screen for RNAs significantly related to HCC prognosis. The expression of differentially expressed RNAs (DERs) was verified using the TCGA dataset and GSE55092. Eighty-five DElncRNAs and 747 DEmRNAs were identified. The mRNAs in the lncRNA-m6A enzyme-mRNA network were primarily involved in mitotic cell division, the p53 signaling pathway, and the cell cycle. Three lncRNAs and 14 mRNAs were significantly associated with HCC prognosis. Furthermore, the expression of 12 DERs differed significantly between patients in the early and advanced stages. LINC00665 was predicted to regulate 11 mRNAs by modulating IGF2BP1, IGF2BP2, and YTHDF1. Thus, this study provides new insights into the roles of lncRNA and m6A enzymes in HCC.

LINC00665 up-regulates SIN3A expression to modulate the progression of colorectal cancer via sponging miR-138-5p

Background

Colorectal cancer (CRC) is a malignant tumor affecting people worldwide. Long noncoding RNAs (lncRNAs) is a crucial factor modulating various cancer progression, including CRC. Long intergenic non-protein coding RNA 665 (LINC00665) has been proven as an oncogene in several cancers, but its function in CRC is still unclear.

Methods

QRT-PCR was performed for RNA quantification. Functional assays were designed and carried to test cell phenotype while mechanism experiments were adopted for detecting the interaction of LINC00665, microRNA-138-5p (miR-138-5p) and SIN3 transcription regulator family member A (SIN3A). In vivo experiments were conducted to test LINC00665 function on modulating CRC tumor progression.

Results

LINC00665 displayed high expression in CRC tissues and cells, and promoted tumor progression in vivo. MiR-138-5p displayed abnormally low expression in CRC, and was verified to be sponged by LINC00665. Furthermore, SIN3A, as the downstream mRNA of miR-138-5p, exerted promoting impacts on CRC cells. Rescue experiments certified that overexpressed SIN3A or silenced miR-138-5p could offset the repressed function of LINC00665 knockdown on CRC progression.

Conclusions

LINC00665 could sponge miR-138-5p to up-regulate SIN3A expression, thus accelerating CRC progression.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02176-4.

Autophagy and gastrointestinal cancers: the behind the scenes role of long non-coding RNAs in initiation, progression, and treatment resistance

Gastrointestinal (GI) cancers comprise a heterogeneous group of complex disorders that affect different organs, including esophagus, stomach, gallbladder, liver, biliary tract, pancreas, small intestine, colon, rectum, and anus. Recently, an explosion in nucleic acid-based technologies has led to the discovery of long non-coding RNAs (lncRNAs) that have been found to possess unique regulatory functions. This class of RNAs is >200 nucleotides in length, and is characterized by their lack of protein coding. LncRNAs exert regulatory effects in GI cancer development by affecting different functions such as the proliferation and metastasis of cancer cells, apoptosis, glycolysis and angiogenesis. Over the past few decades, considerable evidence has revealed the important role of autophagy in both GI cancer progression and suppression. In addition, recent studies have confirmed a significant correlation between lncRNAs and the regulation of autophagy. In this review, we summarize how lncRNAs play a behind the scenes role in the pathogenesis of GI cancers through regulation of autophagy.

LINC00665 Targets miR-214-3p/MAPK1 Axis to Accelerate Hepatocellular Carcinoma Growth and Warburg Effect

Inhibition of aerobic glycolysis is a hopeful method for cancer treatment. In this study, we aimed to explore LINC00665/miR-214-3p/MAPK1 role in regulating cell viability and aerobic glycolysis in hepatocellular carcinoma (HCC). The expressions of LINC00665 in 50 paired HCC tissues and normal tissues were determined by qRT-PCR. Pearson analysis was applied to evaluate the association between the expression levels of miR-214-3p, LINC00665, and MAPK1 in HCC tissues. The interactions between miR-214-3p and LINC00665 or MAPK1 were determined by luciferase reporter assay and RNA immunoprecipitation. CCK-8 and colony formation assays were used for cell viability evaluation. Lactate production, glucose consumption, and ATP levels were measured to assess Warburg effect. The results showed that LINC00665 was overexpressed in HCC, which positively associated with MAPK1 level and negatively associated with miR-214-3p level in HCC tissues. Overexpression of LINC00665 led to significant enhancements in cell viability and colony formation, whereas this effect was weakened when miR-214-3p was overexpressed or MAPK1 was downregulated. In addition, deletion of LINC00665 expression repressed tumor formation in vivo. Mechanically, LINC00665 increased MAPK1 expression through binding to miR-214-3p. Collectively, this study revealed that LINC00665 accelerated cell growth and Warburg effect through sponging miR-214-3p to increase MAPK1 expression in HCC.

Resveratrol inhibits the migration, invasion and epithelial-mesenchymal transition in liver cancer cells through up- miR-186-5p expression

To investigate the molecular mechanism of resveratrol inhibiting the metastasis of liver cancer . HepG2 and Huh7 cells were treated with different concentrations of resveratrol, and the cell viability was determined by CCK-8 assay to determine the optimal concentration of resveratrol for subsequent experiments. The expressions of miR-186-5p in liver cancer tissues and liver cancer cells were determined by quantitative real-time RT-PCR. The migration and invasion of HepG2 and Huh7 cells were detected by wound healing assay and Transwell assay, and the expression levels of epithelial-mesenchymal transition (EMT) related proteins were determined by Western blotting. Resveratrol with concentration of had no effect on the viability of HepG2 and Huh7 cells, so the concentration of resveratrol in subsequent experiments was 6.25 μmol/L. Resveratrol inhibited the wound healing and invasion of liver cancer cells; increased the expression of E-cadherin, and decreased the expression of vimentin and Twist1. The expression of miR-186-5p was significantly down-regulated in liver cancer tissues and cells compared with the adjacent tissues and normal liver cells (both <0.05). Furthermore, resveratrol induced the expression of miR-186-5p in liver cancer cells (both <0.01). Overexpression of miR-186-5p suppressed the migration, invasion and EMT of liver cancer cells. Knockdown of miR-186-5p blocked the inhibition effects of resveratrol on the migration, invasion and EMT of liver cancer cells. Resveratrol could inhibit the metastasis of liver cancer , which might be associated with up-regulating miR-186-5p.

LINC01291 promotes hepatocellular carcinoma development by targeting miR-186-5p/OXSR1 axis

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Recent studies have demonstrated that lncRNAs play an important role in tumorigenesis. LINC01291 has been proven to be involved in the proliferation and migration of different cancers, but the function of LINC01291 in HCC is still unknown.

METHODS

First, the expression of LINC01291 in 50 paired HCC tissues, adjacent normal tissues and HCC cell lines was measured by qRT-PCR. Then, the function of LINC01291 in HCC cell proliferation, migration and invasion was measured by colony formation, Cell Counting Kit-8 (CCK8) assays, wound healing assays and Transwell assays. In addition, E-cadherin, N-cadherin, vimentin and OXSR1 protein expression levels were assessed via western blotting. Luciferase reporter assays were used to prove the relationship between LINC01291 and miR-186-5p as well as miR-186-5p and OXSR1 mRNA. Rescue assays and in vivo experiments further confirmed the LINC01291/miR-186-5p/OXSR1 axis in the progression of HCC.

RESULTS

LINC01291 was upregulated in both HCC tissues and cell lines. Knockdown of LINC01291 inhibited the proliferation, migration, invasion and EMT progression of HCC cells. In addition, LINC01291 could overexpress OXSR1 by sponging miR-186-5p, and OXSR1 overexpression or miR-186-5p inhibition could rescue the effect of LINC01291 knockdown in YY-8103 cell lines. In addition, lentiviral sh-LINC01291 could effectively inhibit the growth of subcutaneous YY-8103 xenograft tumors, while the anticancer effect could be reversed by cotransfection with in-miR-186-5p or ov-OXSR1.

CONCLUSIONS

LINC01291 can promote the proliferation, migration, invasion and EMT of HCC cells via the miR-186-5p/OXSR1 axis, and sh-LINC01291 can inhibit tumor growth in a xenograft mouse model.

LINC00665 Facilitates the Malignant Processes of Osteosarcoma by Increasing the RAP1B Expression via Sponging miR-708 and miR-142-5p

Osteosarcoma (OS) is a kind of fatal primary bone tumors in adolescents and young adults. Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs which occupy a part of the latest hot topics. We aimed to investigate the roles of lncRNA LINC00665 in OS in this study. In this study, we found that LINC00665 was highly expressed in OS tissues and cell lines, and its high expression was associated with malignant feature and poor prognosis of OS. In OS cells, LINC00665 could facilitate the proliferation, migration, and invasion to play an oncogenic role. Mechanistically, LINC00665 served as a sponge for miR-708 and miR-142-5p and positively mediated the expression of their target RAP1B. Finally, we confirmed that LINC00665 exercised its biological functions by mediating RAP1B. In conclusion, LINC00665 is overexpressed in OS and facilitates the malignant processes of OS cells by increasing the RAP1B expression via sponging miR-708 and miR-142-5p.

circ-PRKCI targets miR-1294 and miR-186-5p by downregulating FOXK1 expression to suppress glycolysis in hepatocellular carcinoma

Numerous human circular RNAs (circRNAs/circ) have been functionally characterized. However, the potential role of circ-protein kinase C iota (PRKCI) in hepatocellular carcinoma (HCC) remains unknown. The effects of each transfection and expression levels of circ-PRKCI, microRNA (miR)-1294, miR-186-5p and forkhead box K1 (FOXK1) in HCC cells were analyzed using reverse transcription-quantitative PCR analysis. The interactions between circ-PRKCI and miR-1294 or miR-186-5p, and miR-1294 or miR-186-5p and FOXK1 were validated using dual luciferase reporter assays. The viability, invasion and migration of HCC cells were determined using Cell Counting Kit-8, Transwell and wound healing assays, respectively. The expression levels of FOXK1, hexokinase-2 (HK2), glucose transporter 1 (GLUT1) and lactate dehydrogenase A (LDHA) in HCC cells were analyzed using western blotting. The levels of glucose and lactic acid in the cultured supernatant were detected using commercially available kits. The results of the present study revealed that miR-1294 and miR-186-5p expression levels were downregulated in the HCC cell line, HCCLM3, and were subsequently downregulated by circ-PRKCI overexpression and upregulated by the knockdown of circ-PRKCI. circ-PRKCI overexpression promoted the viability, invasion and migration of HCCLM3 cells, which was also reversed by the overexpression of miR-1294 and miR-186-5p. In addition, the overexpression of circ-PRKCI upregulated FOXK1 expression levels, while the overexpression of miR-1294 and miR-186-5p downregulated FOXK1 expression levels. Conversely, the knockdown of circ-PRKCI expression downregulated FOXK1 expression levels, while the knockdown of miR-1294 and miR-186-5p upregulated FOXK1 expression levels. Furthermore, circ-PRKCI was identified to target miR-1294 and miR-186-5p, and miR-1294 and miR-186-5p were subsequently found to target FOXK1. The overexpression of circ-PRKCI also increased glucose and lactic acid levels, while the knockdown of FOXK1 decreased glucose and lactic acid levels. The knockdown of circ-PRKCI decreased glucose and lactic acid levels, which were reversed by FOXK1 overexpression. In conclusion, the findings of the present study suggested that circ-PRKCI may promote the viability, invasion and migration of HCC cells by sponging miR-1294 and miR-186-5p to upregulate FOXK1 expression levels.

The Impact of Long Non-Coding RNAs in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the utmost deadly human malignancies. This type of cancer has been associated with several environmental, viral, and lifestyle risk factors. Among the epigenetic factors which contribute in the pathogenesis of HCC is dysregulation of long non-coding RNAs (lncRNAs). These transcripts modulate expression of several tumor suppressor genes and oncogenes and alter the activity of cancer-related signaling axes. Several lncRNAs such as NEAT1, MALAT1, ANRIL, and SNHG1 have been up-regulated in HCC samples. On the other hand, a number of so-called tumor suppressor lncRNAs namely CASS2 and MEG3 are down-regulated in HCC. The interaction between lncRNAs and miRNAs regulate expression of a number of mRNA coding genes which are involved in the pathogenesis of HCC. H19/miR-15b/CDC42, H19/miR-326/TWIST1, NEAT1/miR-485/STAT3, MALAT1/miR-124-3p/Slug, MALAT1/miR-195/EGFR, MALAT1/miR-22/SNAI1, and ANRIL/miR-144/PBX3 axes are among functional axes in the pathobiology of HCC. Some genetic polymorphisms within non-coding regions of the genome have been associated with risk of HCC in certain populations. In the current paper, we describe the recent finding about the impact of lncRNAs in HCC.

Long intergenic noncoding RNA 00665 promotes proliferation and inhibits apoptosis in colorectal cancer by regulating miR-126-5p

Long intergenic noncoding RNAs (lincRNAs) regulate a series of biological processes, and their anomalous expression plays critical roles in the progression of multiple malignancies, including colorectal cancer (CRC). Although many studies have reported the oncogenic function of LINC00665 in multiple cancers, few studies have explored its role in CRC. The aim of this study was to assess the effect of LINC00665 on the malignant behaviors of CRC and explore the underlying regulatory mechanism of LINC00665. LINC00665 was significantly upregulated in CRC. A loss-of-function assay revealed that LINC00665 downregulation inhibited the proliferation and promoted the apoptosis of CRC cells, which was mediated by cyclin D1, CDK4, caspase-9 and caspase-3. Through mechanistic exploration, we found that miR-126-5p directly bound to LINC00665. Moreover, LINC00665 and miR-126-5p both regulated PAK2 and FZD3 expression. Mechanistically, miR-126-5p was predicted and further verified as a target of both PAK2 and FZD3. These findings demonstrate that LINC00665 might play an important pro-proliferative and antiapoptotic role in CRC and might be a potential biomarker and a new therapeutic target for CRC.

LINC00665 activates Wnt/β-catenin signaling pathway to facilitate tumor progression of colorectal cancer via upregulating CTNNB1

Background LINC00665 is a newly identified oncogene, which has been reported to be oncogene in various cancers. Nevertheless, its role in the progression of colorectal cancer (CRC) remains obscure to the extent. This study aimed at exploring the role and mechanism of LINC00665 in CRC progression. Materials and methods RNA and protein expression were detected via qRT-PCR and western blot. Functional assays were conducted to investigate the role of LINC00665 in the CRC cellular processes. TOP/FOP assay was performed to detect the activity of Wnt/β-catenin signaling pathway. Mechanism investigations were carried out to explore the regulatory relationship among genes. Results LINC00665 was overtly expressed in CRC cell lines at high levels. Functionally, silencing of LINC00665 could curb in vitro CRC cell growth, migration and invasion, while stimulating cell apoptosis. Mechanically, LINC00665 sponged miR-214-3p to up-regulate CTNNB1 expression, consequently activating Wnt/β-catenin signaling pathway. Furthermore, LINC00665 could bind to U2AF2 and enhance the association between U2AF2 and CTNNB1, increasing the stability of CTNNB1. CTNNB1 overexpression could reverse the suppressive effects of LINC00665 downregulation. Conclusion LINC00665 stimulates CRC progression through the activation of Wnt/β-catenin signaling pathway, which hopefully might be a therapeutic target for CRC.

Atorvastatin Upregulates microRNA-186 and Inhibits the TLR4-Mediated MAPKs/NF-κB Pathway to Relieve Steroid-Induced Avascular Necrosis of the Femoral Head

Steroid-induced avascular necrosis of the femoral head (SANFH) is caused by the death of active components of the femoral head owing to hormone overdoses. The use of lipid-lowering drugs to prevent SANFH in animals inspired us to identify the mechanisms involving Atorvastatin (Ato) in SANFH. However, it is still not well understood how and to what extent Ato affects SANFH. This study aimed to figure out the efficacy of Ato in SANFH and the underlying molecular mechanisms. After establishment of the SANFH model, histological evaluation, lipid metabolism, inflammatory cytokines, oxidative stress, apoptosis, and autophagy of the femoral head were evaluated. The differentially expressed microRNAs (miRs) after Ato treatment were screened out using microarray analysis. The downstream gene and pathway of miR-186 were predicted and their involvement in SANFH rats was analyzed. OB-6 cells were selected to simulate SANFH in vitro. Cell viability, cell damage, inflammation responses, apoptosis, and autophagy were assessed. Ato alleviated SANFH, inhibited apoptosis, and promoted autophagy. miR-186 was significantly upregulated after Ato treatment. miR-186 targeted TLR4 and inactivated the MAPKs/NF-κB pathway. Inhibition of miR-186 reversed the protection of Ato on SANFH rats, while inhibition of TLR4 restored the protective effect of Ato. Ato reduced apoptosis and promoted autophagy of OB-6 cells by upregulating miR-186 and inhibiting the TLR4/MAPKs/NF-κB pathway. In conclusion, Ato reduced apoptosis and promoted autophagy, thus alleviating SANFH via miR-186 and the TLR4-mediated MAPKs/NF-κB pathway.

FOXD1, negatively regulated by miR-186, promotes the proliferation, metastasis and radioresistance of nasopharyngeal carcinoma cells

BACKGROUND

Foxhead box D1 (FOXD1) is validated to be over-expressed in a variety of human malignancies and promotes cancer progression. Nevertheless, the role of FOXD1 and the associated mechanism in nasopharyngeal carcinoma (NPC) remain largely unknown.

METHODS

A total of seventy-five cases of NPC tissue samples were collected. FOXD1 expression in NPC tissues and cells (SUNE1, CNE1, CNE2, and HONE1) was detected using immunohistochemistry and Western blot, respectively. The relationship between FOXD1 expression and clinicopathological parameters of NPC patients was analyzed. FOXD1 mRNA and miR-186 expression in NPC tissues and cells was detected using quantitative polymerase chain reaction (qPCR). The cell viability of NPC cells was detected using CCK-8 assay. Colony survival of NPC cells exposed to different doses of radiation was detected using colony formation assay. Transwell assay was used to evaluate the migration and invasion of NPC cells. The dual-luciferase reporter gene assay was employed to verify the targeting relationship between miR-186 and FOXD1.

RESULTS

FOXD1 was over-expressed in NPC tissues (average fold change on mRNA level = 4.72), and its high expression was correlated to NPC positive lymph node metastasis and tissue differentiation. The over-expression of FOXD1 promoted the proliferation, migration, invasion and radio-resistance of NPC cells. On the contrary, the knock-down of FOXD1 inhibited the malignant phenotypes of the above cells. It was verified that FOXD1 was one of the downstream targets of miR-186 and was negatively regulated by it.

CONCLUSION

FOXD1, which is negatively regulated by miR-186, acts as a novel oncogene in NPC and serves as potential biomarker and therapeutic target for NPC. The research will provide great theoretical basis for further clinical diagnosis and therapy.

LncRNA HCP5 promotes neuroblastoma proliferation by regulating miR-186-5p/MAP3K2 signal axis

INTRODUCTION

Neuroblastoma (NB) is the most common solid tumor in children. Studies showed that long-chain noncoding RNA (lncRNA) HCP5 played an important role in tumorigenesis, but its role in NB remained unclear. This study aims to determine the role of HCP5 in NB and its possible molecular mechanism.

METHODS

We analyzed the expression levels of miRNA-186-5p and HCP5 in neuroblastoma and neuroblastoma cell lines SHSY-5Y, Kelly, NBL-S and SK-N-AS, and explored their roles.

RESULTS

We found that the HCP5 expression was up-regulated in NB tissues and cells. The higher the HCP5 expression in NB cells, the stronger the ability of clone formation. Down regulation of the HCP5 expression inhibited the proliferation of NB cells and the growth of subcutaneous transplanted tumor in nude mice. HCP5 could competitively bind miR-186-5p, while miR-186-5p could target the 3'-UTR of MAP3K2. The expression level of miR-186-5p was down regulated while the expression level of MAP3K2 was up-regulated in NB tissues. The expression level of HCP5 and miR-186-5p, the expression level of miR-186-5p and MAP3K2 were negatively correlated. The decreased proliferation of NB cells induced by down-regulation of HCP5 expression can be counteracted by miR-186-5p inhibitor or MAP3K2, and vice versa.

CONCLUSION

This study showed that lncRNA HCP5, as ceRNA, regulated MAP3K2 to promote NB progression through competitive binding of miR-186-5p. We revealed a new signaling pathway that mediates NB, which provided a new target for the diagnosis and treatment of NB.

LINC00665 promotes the progression of acute myeloid leukemia by regulating the miR-4458/DOCK1 pathway

This study aimed to explore the role of LINC00665, miR-4458 and DOCK1 and their interactions in the development of acute myeloid leukemia (AML). The relative expression of LINC00665, miR-4458 and DOCK1 in AML samples was measured using qRT-PCR, and the protein level of DOCK1 in AML cell lines was examined using western blot. CCK8, BrdU, transwell, cell adhesion, and caspase-3 activity assays were carried out to evaluate the viability, proliferation, migration, adhesion, and apoptosis of AML cells, respectively. Luciferase reporter, RIP, and RNA pull-down assays were also performed to confirm the target relationship among LINC00665, miR-4458 and DOCK1. Findings revealed that LINC00665 and DOCK1 were aberrantly overexpressed in AML tissues and that the expression of miR-4458 was low in AML tissues. Silencing LINC00665 or DOCK1 presented significant restriction to the proliferation, migration and adhesion of AML cells. Apart from that, it was found that inhibiting miR-4458 could enhance the proliferation, migration and adhesion of AML cells but suppress the apoptosis of AML cells. Experimental results also indicated that LINC00665 exerted its positive function on AML cells by sponging miR-4458 and that miR-4458 influenced the progression of AML cells by targeting DOCK1 directly. Overall, this finding not only provided a novel molecular pathway for the diagnosis and treatment of AML but also showed that LINC00665 could enhance the progression of AML by regulating the miR-4458/DOCK1 pathway.

LINC00665 functions as a competitive endogenous RNA to regulate AGTR1 expression by sponging miR‑34a‑5p in glioma

Glioma is the most aggressive tumor of the central nervous system. Long non‑coding RNAs (lncRNAs) may be involved in modulating tumor generation. The present study analyzed an lncRNA microarray of glioma and selected long intergenic non‑protein coding RNA 665 (LINC00665) as the research object. The mode of expression and biological function of LINC00665 in glioma were assessed using lncRNA microarray and RT‑qPCR analyses. Gain‑of‑function assays and/or loss‑of‑function assays were implemented to explore the role of LINC00665 in the progression of glioma. Dual‑luciferase reporter and RNA immunoprecipitation assays explored the downstream molecular mechanism of LINC00665. The function of the molecular pathway in progression of glioma was analyzed using rescue assays. High expression of LINC00665 was marked in glioma tissues and cells, which correlated with an unsatisfactory prognosis. Upregulation of LINC00665 significantly promoted the proliferation and invasion of glioma cells. LINC00665 acted as a competing endogenous RNA by sponging miR‑34a‑5p to upregulate angiotensin II receptor type 1 (AGTR1). LINC00665 promoted the progression of glioma by acting as a competitive endogenous RNA to competitively bind to miR‑34a‑5p and mediate AGTR1 expression.

Progress in understanding the role of lncRNA in programmed cell death

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides but not translated into proteins. LncRNAs regulate gene expressions at multiple levels, such as chromatin, transcription, and post-transcription. Further, lncRNAs participate in various biological processes such as cell differentiation, cell cycle regulation, and maintenance of stem cell pluripotency. We have previously reported that lncRNAs are closely related to programmed cell death (PCD), which includes apoptosis, autophagy, necroptosis, and ferroptosis. Overexpression of lncRNA can suppress the extrinsic apoptosis pathway by downregulating of membrane receptors and protect tumor cells by inhibiting the expression of necroptosis-related proteins. Some lncRNAs can also act as competitive endogenous RNA to prevent oxidation, thereby inhibiting ferroptosis, while some are known to activate autophagy. The relationship between lncRNA and PCD has promising implications in clinical research, and reports have highlighted this relationship in various cancers such as non-small cell lung cancer and gastric cancer. This review systematically summarizes the advances in the understanding of the molecular mechanisms through which lncRNAs impact PCD.

MicroRNA‑186‑5p downregulation inhibits osteoarthritis development by targeting MAPK1

As a chronic degenerative joint disease, the characteristics of osteoarthritis (OA) are degeneration of articular cartilage, subchondral bone sclerosis and bone hyperplasia. It has been reported that microRNA (miR)-186-5p serves a key role in the development of various tumors, such as osteosarcoma, non-small-cell lung cancer cells, glioma and colorectal cancer. The present study aimed to investigate the effect of miR-186-5p in OA. Different concentrations of IL-1β were used to treat the human chondrocyte cell line CHON-001 to simulate inflammation, and CHON-001 cell injury was assessed by detecting cell viability, apoptosis, caspase-3 activity and the levels of TNF-α, IL-8 and IL-6. Subsequently, reverse transcription-quantitative PCR was performed to measure miR-186-5p expression. The results demonstrated that following IL-1β treatment, CHON-001 cell viability was suppressed, apoptosis was promoted, the caspase-3 activity was significantly enhanced and the release of TNF-α, IL-8 and IL-6 was increased. In addition, IL-1β treatment significantly upregulated miR-186-5p expression in CHON-001 cells. It was also identified that MAPK1 was a target gene of miR-186-5p, and was negatively regulated by miR-186-5p. miR-186 inhibitor and MAPK1-small interfering RNA (siRNA) were transfected into CHON-001 cells to investigate the effect of miR-186-5p on CHON-001 cell injury induced by IL-1β. The results demonstrated that miR-186 inhibitor suppressed the effects of IL-1β on CHON-001 cells, and these effects were reversed by MAPK1-siRNA. In conclusion, the present results indicated that miR-186-5p could attenuate IL-1β-induced chondrocyte inflammation damage by increasing MAPK1 expression, suggesting that miR-186-5p may be used as a potential therapeutic target for OA.

LncRNA NEAT1 promotes cell proliferation, migration, and invasion via the miR-186-5p/PTP4A1 axis in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a highly aggressive and malignant tumor. In this study, the effect and molecular mechanism of nuclear enriched abundant transcript 1 (NEAT1) in CCA were elucidated. The expressions of NEAT1, microRNA-186-5p (miR-186-5p), and PTP4A1 were measured by quantitative real-time PCR. The protein levels were measured by Western blotting. Kaplan-Meier analysis was performed to create survival curves. The interactions between NEAT1, miR-186-5p, and PTP4A1 were assessed through the dual luciferase reporter assay. Additionally, the cell proliferation, apoptosis, migration, and invasion were measured by colony formation, flow cytometry, the Transwell assay, and the wound healing assay, respectively. NEAT1 and PTP4A1 were significantly upregulated in CCA tissues and cells, but miR-186-5p was downregulated. NEAT1 expression was negatively correlated with the survival of CCA patients and has remarkable correlation with serum CA199 levels and lymph node metastasis. Besides, NEAT1 could act as a molecular sponge for miR-186-5p to upregulate PTP4A1 expression. More importantly, the knockdown of NEAT1 or overexpression of miR-186-5p inhibited the proliferation, migration and invasion of CCA cells, and the inhibition of miR-186-5p reversed the effects of the knockdown of NEAT1. In addition, NEAT1 could also activate the PI3K/AKT signaling pathway and regulate the epithelial-mesenchymal transition (EMT) through the miR-186-5p/PTP4A1 axis. In conclusion, NEAT1 was involved in cell proliferation, migration and invasion in CCA, and the NEAT1/miR-186-5p/PTP4A1/PI3K/AKT axis indicated novel regulatory mechanisms and therapeutics for the treatment of CCA.

LINC00665 enhances tumorigenicity of endometrial carcinoma by interacting with high mobility group AT-hook 1

Background

Endometrial carcinoma is a frequently diagnosed cancer among females. LncRNAs are reported to be associated with various cancers. Their biological roles in endometrial carcinoma progression is an emerging scientific area. LINC00665 can exert a significant role in many cancers. However, its potential function in endometrial carcinoma is still poorly known.

Method

qRT-PCR was carried out to test expression of LINC00665 and HMGA1. Western blot analysis was carried out to detect protein expression of HMGA1. Cell proliferation was evaluated using Cell Counting Kit-8 (CCK-8) and EdU assay. Flow cytometry assay was used to determine cell apoptosis and cell cycle. Wound healing and transwell invasion assay was carried out to test cell migration and invasion. Immunohistochemical staining and HE staining were conducted to assess Ki-67 and tumor growth respectively.

Results

Expression of LINC00665 in clinical endometrial carcinoma tissues and cells was obviously up-regulated. Loss of LINC00665 could repress endometrial carcinoma cell viability, induce cell apoptosis and block cell cycle in G1 phase. KLE and HHUA cell migration and invasion ability were depressed by LINC00665 shRNA. Decrease of LINC00665 suppressed endometrial carcinoma tumorigenicity in vivo. RIP assay proved that LINC00665 directly bound with HMGA1 protein. shRNA of HMGA1 obviously restrained endometrial carcinoma cell growth and cell invasion.

Conclusions

LINC00665 might promote endometrial carcinoma progression by positively modulating HMGA1.

Long non-coding RNA LINC00665 promotes melanoma cell growth and migration via regulating the miR-224-5p/VMA21 axis

Melanoma is an aggressive malignant skin tumor endangering the health of patients. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been increasingly reported to be implicated in the carcinogenesis of melanoma. Long intergenic non-coding RNA 00665 (LINC00665) has been found to exert important regulatory roles in some cancers, yet its function in melanoma remains to be investigated. QRT-PCR analysis was conducted to evaluate the relative expression of RNAs. Functional experiments in vitro including colony formation, EdU, wound-healing and transwell assays, as well as in vivo xenograft assays, were utilized to study the role of LINC00665 in melanoma. Mechanical experiments were implemented to probe into the molecular linkage of LINC00665, miR-224-5p and VMA21. LINC00665 was abnormally highly expressed in melanoma cells. Silencing LINC00665 could inhibit the proliferation and migration of melanoma cells. LINC00665 sponged miR-224-5p to upregulate VMA21. VMA21 knockdown exerted similarly interfering effects on above biological processes in melanoma cells. However, VMA21 overexpression abolished the in vitro and in vivo outcomes of LINC00665 silencing. LINC00665 promotes proliferative and migrating abilities of melanoma cells via targeting miR-224-5p/VMA21 axis.

Steroid 5 alpha-reductase 3 (SRD5A3) promotes tumor growth and predicts poor survival of human hepatocellular carcinoma (HCC)

Steroid 5 alpha-reductase 3 (SRD5A3) is an important molecule in glycosylation metabolism and steroid hormone formation. It is differentially expressed in human fetal liver, endometrial cancer and prostate cancer; however, its prognostic value and biological function in hepatocellular carcinoma (HCC) remain unclear. Here, bioinformatics analysis was employed to explore the expression and prognostic significance of SRD5A3 in various cancers including HCC. Additionally, clinical specimens of HCC were applied to analyze the expression of SRD5A3. SRD5A3-underexpressed HCC cell lines were established to test the effect of SRD5A3 on cell proliferation in in vitro and in vivo. We found that the elevated expression of SRD5A3 was common in many cancers with poor prognosis. Moreover, public datasets and our specimens revealed that SRD5A3 was also upregulated in HCC tissues and associated with clinical stage and patient’s gender. Kaplan-Meier survival analysis showed that higher SRD5A3 level predicted poor overall survival, progression-free survival, relapse-free survival and disease specific survival in HCC patients. Further experiments showed that the lack of SRD5A3 inhibited the growth of HCC. Collectively, these findings indicate that SRD5A3 functions as an oncogene and might serve as a potential biomarker for prognosis and a therapeutic target for HCC.

Knockdown of LINC00665 inhibits proliferation and invasion of breast cancer via competitive binding of miR-3619-5p and inhibition of catenin beta 1

Background

Long intergenic non-protein coding RNA00665 (LINC00665) plays a crucial tumorigenic role in many cancers, such as gastric cancer and lung adenocarcinoma. However, its role and mechanism of action in the progression of breast cancer (BC) are unknown.

Methods

LINC00665 expression levels were determined using quantitative polymerase chain reaction analysis with BC tissues and cell lines. BC cell proliferation was tested by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, whereas BC cell migration and invasion capabilities were analyzed by performing transwell migration assays. Percentages of apoptotic cells were measured by flow cytometry. Interactions between LINC00665 and miR-3169-5p were examined by performing luciferase reporter assays, and the expression levels of proteins, such as β-catenin, were examined by western blot analysis.

Results

LINC00665 was expressed at high levels in BC tissues and cells. Upregulated LINC00665 expression correlated with tumor size and tumor, node, and metastasis stages, but not with the age of patients. LINC00665 knockdown inhibited BC cell proliferation, migration, and invasion, whereas it promoted apoptosis. Moreover, bioinformatics analysis and the luciferase reporter assay revealed that LINC00665 bound the microRNA (miR) miR-3619-5p. miR-3619-5p expression correlated negatively with LINC00665 expression in BC tissues. miR-3619-5p overexpression inhibited BC cell proliferation, migration, and invasion, but promoted apoptosis. Simultaneous knockdown of LINC00665 and miR-3619-5p led to increased cell proliferation, migration, and invasion, and inhibited apoptosis. Additionally, catenin beta 1, which encodes the β-catenin protein, was the target gene of miR-3619-5p. β-catenin expression clearly decreased after LINC00665 knockdown and miR-3619-5p overexpression, but increased after simultaneous knockdown of LINC00665 and miR-3619-5p.

Conclusion

LINC00665 knockdown inhibited BC cell proliferation and invasion by binding miR-3619-5p and inhibiting β-catenin expression.

The long noncoding RNA FTX promotes a malignant phenotype in bone marrow mesenchymal stem cells via the miR-186/c-Met axis

Gliomas are the most common and aggressive primary tumours of the central nervous system in adults. Bone marrow-derived mesenchymal stem cells (BMSCs) are an important component of the glioma microenvironment. Our previous study indicated that BMSCs in the glioma microenvironment could be induced to malignantly transform by glioma stem cells (GSCs). The malignant transformation of BMSCs is closely related to glioma progression; however, the underlying mechanism of this transformation has not been fully clarified. In this study, we found that compared with the levels in normal BMSCs, the levels of the long noncoding RNA FTX transcript XIST regulator (lncRNA-FTX) were increased in malignantly transformed BMSCs (tBMSCs), which was associated with the proliferation, migration and invasion of tBMSCs. Next, by using a luciferase reporter assay and an RNA pull-down assay, we found that lncRNA-FTX acted as a sponge for miR-186 in tBMSCs. Further research revealed that miR-186 could bind to the 3'-UTR (untranslated region) of c-Met, which acts as an oncogene in gliomas. Through functional assays, we showed that lncRNA-FTX could regulate c-Met expression in tBMSCs in a miR-186-dependent manner. Based on these data, we concluded that lncRNA-FTX plays a key role in the GSC-mediated malignant transformation of BMSCs in the glioma microenvironment, which is of great significance for further understanding the pathogenesis of glioma.

Role of long noncoding RNA-mediated competing endogenous RNA regulatory network in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are noncoding RNAs (ncRNAs) that occupy over 90% of the human genome, and their main function is to directly or indirectly regulate messenger RNA (mRNA) expression and participate in the tumorigenesis and progression of malignances. In particular, some lncRNAs can interact with miRNAs as competing endogenous RNAs (ceRNAs) to modulate mRNA expression. Accordingly, these RNA molecules are interrelated and coordinate to form a dynamic lncRNA-mediated ceRNA regulatory network. Mounting evidence has revealed that lncRNAs that act as ceRNAs are closely related to tumorigenesis. To date, numerous studies have established many different regulatory networks in hepatocellular carcinoma (HCC), and perturbations in these ceRNA interactions may result in the initiation and progression of HCC. Herein, we emphasize recent advances concerning the biological function of lncRNAs as ceRNAs in HCC, with the aim of elucidating the molecular mechanism underlying these HCC-related RNA molecules and providing novel insights into the diagnosis and treatment of HCC.

lncRNA LINC00665 Stabilized by TAF15 Impeded the Malignant Biological Behaviors of Glioma Cells via STAU1-Mediated mRNA Degradation

Glioma is a brain cancer characterized by strong invasiveness with limited treatment options and poor prognosis. Recently, dysregulation of long non-coding RNAs (lncRNAs) has emerged as an important component in cellular processes and tumorigenesis. In this study, we demonstrated that TATA-box binding protein associated factor 15 (TAF15) and long intergenic non-protein coding RNA 665 (LINC00665) were both downregulated in glioma tissues and cells. TAF15 overexpression enhanced the stability of LINC00665, inhibiting malignant biological behaviors of glioma cells. Both metal regulatory transcription factor 1 (MTF1) and YY2 transcription factor (YY2) showed high expression levels in glioma tissues and cells, and their knockdown inhibited malignant progression. Mechanistically, overexpression of LINC00665 was confirmed to destabilize MTF1 and YY2 mRNA by interacting with STAU1, and knockdown of STAU1 could rescue the MTF1 and YY2 mRNA degradation caused by LINC00665 overexpression. G₂ and S-phase expressed 1 (GTSE1) was identified as an oncogene in glioma, and knockdown of MTF1 or YY2 decreased the mRNA and protein expression levels of GTSE1 through direct binding to the GTSE1 promoter region. Our study highlights a key role of the TAF15/LINC00665/MTF1(YY2)/GTSE1 axis in modulating the malignant biological behaviors of glioma cells, suggesting novel mechanisms by which lncRNAs affect STAU1-mediated mRNA stability, which can inform new molecular therapies for glioma.

The Dual Role of miR-186 in Cancers: Oncomir Battling With Tumor Suppressor miRNA

MicroRNAs (miRNAs) are a class of small non-coding RNAs which regulate gene expression at post-transcriptional level. Alterations of miR-186 expression were demonstrated in numerous cancers, shown to play a vital role in oncogenesis, invasion, metastasis, apoptosis, and drug resistance. MiR-186 was documented as a tumor suppressor miRNA in the majority of studies, while conflicting reports verified miR-186 as an oncomir. The contradictory role in cancers may impede the application of miR-186, as well as other dual-functional miRNAs, as a diagnostic and therapeutic target. This review emphasizes the alterations and functions of miR-186 in cancers and discusses the mechanisms behind the contradictory findings. Among these, target abundance and dose-dependent effects of miR-186 are highlighted. The paper aims to review the challenges involved in developing diagnostic and therapeutic strategies for cancer treatment based on dual-functional miRNAs.