DLX6-AS1 promotes cell proliferation, migration and EMT of gastric cancer through FUS-regulated MAP4K1

FUS and METTL3 collaborate to regulate RNA maturation, preventing unfolded protein response and promoting gastric cancer progression

FUS-mediated alternative splicing and METTL3-regulated RNA methylation play crucial roles in RNA processing. The purpose of this study was to investigate the interactive roles of FUS and METTL3 in gastric cancer (GC) progression. RNA sequencing data were obtained from the TCGA-STAD dataset. Differentially expressed genes (DEGs) were analyzed across groups stratified by the medians of FUS, METTL3, and NEAT1, respectively. Endoplasmic reticulum (ER) stress markers PERK, IRE1, pIRE1, Bip, and CHOP, as well as related apoptosis stress markers PARP, cleaved-PARP, (Cleaved) Caspase 7, and (Cleaved) Caspase 3, were assessed through western blotting. Alternative splicing and N6-methyladenosine (m(6)A) methylation of specific genes were detected with MeRIP-PCR. Finally, in vivo experiments were conducted using nude mice bearing sh-FUS-transfected HGC27 xenograft tumors. FUS and METTL3 expression levels were elevated in GC tissues. A significant overlap of DEGs was observed between the FUS- and METTL3-stratified groups. These overlapping DEGs were predominantly enriched in mRNA processing and protein processing in the ER. ER stress and apoptosis were induced by sh-FUS or sh-METTL3, which was further enhanced by ER stress inducer tunicamycin in both MKN45 and HGC27 cells. Similarly, DEGs for NEAT1 high- and low-expressed groups were enriched in protein processing in the ER and spliceosome. To a lesser extent, ER stress was also induced by sh-NEAT1 and enhanced by tunicamycin in HGC27 cells. Furthermore, sh-FUS or sh-METTL3 influenced alternative splicing and methylation of specific mRNAs, including FUS, NEAT1, PCNA, MCM2, and BIRC5. Tumor progression was inhibited by sh-FUS in mice, and ER stress and apoptosis were induced, which were further enhanced by tunicamycin. FUS and METTL3 collaborate to facilitate RNA maturation. Inhibiting FUS or METTL3 promoted ER stress and apoptosis and inhibited progression in GC.

ZC3H13 knockdown enhances the inhibitory effect of sevoflurane on gastric cancer cell malignancy by regulating the N6-methyladenosine modification of the lncRNA DLX6-AS1

Sevoflurane, an inhalation anesthetic, has been shown to suppress cancer development. In this study, we investigated the specific mechanisms involving sevoflurane, zinc-finger CCCH-type containing 13 (ZC3H13), and lncRNA DLX6-AS1 in gastric cancer (GC) progression, focusing on the N6-methyladenosine (m6A) modification of long non-coding RNAs (lncRNAs). We used quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses to measure the levels of ZC3H13 and lncRNA DLX6-AS1 in GC tissues and cells. Furthermore, we conducted Cell Counting Kit-8, colony formation, Transwell, and tumor xenograft assays to evaluate changes in GC cell malignancy following cell transfection and sevoflurane treatment. Additionally, actinomycin D, methylated RNA immunoprecipitation, and qRT-PCR assays were performed to examine the regulatory effects of ZC3H13 on the DLX6-AS1 m6A modification. We detected elevated levels of ZC3H13 in GC samples, while ZC3H13 silencing inhibited GC cell proliferation, migration, and invasion. Silencing ZC3H13 also enhanced the inhibitory effects of sevoflurane on GC cell malignancy. Moreover, we found that the increased expression of DLX6-AS1 in GC cells could be suppressed by ZC3H13 through the mediation of the m6A modification of DLX6-AS1, thereby reducing DLX6-AS1 stability. In conclusion, ZC3H13 knockdown enhances the inhibitory effect of sevoflurane on GC cell malignancy by inducing DLX6-AS1 m6A modification. Our findings may help identify potential therapeutic targets for the treatment of GC.

Crosstalk between long noncoding RNA and microRNA in Cancer

miRNAs and lncRNAs play a central role in cancer-associated gene regulations. The dysregulated expression of lncRNAs has been reported as a hallmark of cancer progression, acting as an independent prediction marker for an individual cancer patient. The interplay of miRNA and lncRNA decides the variation of tumorigenesis that could be mediated by acting as sponges for endogenous RNAs, regulating miRNA decay, mediating intra-chromosomal interactions, and modulating epigenetic components. This paper focuses on the influence of crosstalk between lncRNA and miRNA on cancer hallmarks such as epithelial-mesenchymal transition, hijacking cell death, metastasis, and invasion. Other cellular roles of crosstalks, such as neovascularization, vascular mimicry, and angiogenesis were also discussed. Additionally, we reviewed crosstalk mechanism with specific host immune responses and targeting interplay (between lncRNA and miRNA) in cancer diagnosis and management.

Long non-coding RNAs and gastric cancer: An update of potential biomarkers and therapeutic applications

The frequent metastasis of gastric cancer (GC) complicates the cure and therefore the development of effective diagnostic and therapeutic approaches is urgently necessary. In recent years, lncRNA has emerged as a drug target in the treatment of GC, particularly in the areas of cancer immunity, cancer metabolism, and cancer metastasis. This has led to the demonstration of the importance of these RNAs as prognostic, diagnostic and therapeutic agents. In this review, we provide an overview of the biological activities of lncRNAs in GC development and update the latest pathological activities, prognostic and diagnostic strategies, and therapeutic options for GC-related lncRNAs.

miR-2682-3p antagonizes its host lncRNA-MIR137HG by interacting with the same target FUS to regulate the progression of gastric cancer

Background

The mechanism of long non-coding RNA MIR137HG in human gastric cancer (GC) is currently unknown. In the present study, we aimed to explore the function and mechanism of MIR137HG in gastric cancer.

Methods

The expression of lncRNA-MIR137HG in 69 gastric cancer samples and their paired surgical margin (SM) tissue samples were tested by QRT-PCR. UCSC was used to find the gene location relationship among MIR137HG and its embedded miRNAs. TargetScan was used to predict the targets of miR-2682-3p. Starbase was used to predict the candidate proteins that interacted with MIR137HG. Western blot, co-focus, and RIP assay were used to verify the direct interaction between MIR137HG and FUS (fused in sarcoma/translocated in liposarcoma, FUS/TLS), while dual-luciferase reporter assay was used to confirm the interaction between miR-2682-3p and FUS. Cell migration assays, colony formation, and xenografts assay were used to investigate the function of MIR137HG and miR-2682-3p to tumor growth and metastasis. Western blot assay was used to explore the downstream candidate protein of FUS.

Results

Data showed that MIR137HG expressed significantly higher in GC than in SM. MIR137HG promoted colony formation and migration in vitro and promoted tumor formation and metastasis in vivo. MIR137HG is distributed in both the nucleus and cytoplasm. It was co-located with FUS and could directly interact with FUS, which might interact with other proteins, such as MET(MET-proto-oncogene, receptor tyrosine kinase), RHOC(ras homolog family member), and CTNNB1(catenin beta1). These proteins may involve different signaling pathways to regulate gastric cancer progression. By contrast, the embedded miR-2682-3p could antagonize the series functions of its host lncRNA-MIR137HG by targeting FUS.

Conclusions

lncRNA-MIR137HG promoted growth and metastasis in gastric cancer by interacting with FUS, while miR-2682-3p could inhibit the function of MIR137HG via the same target FUS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09740-9.

Strategies of LncRNA DLX6-AS1 on Study and Therapeutics

Accumulating evidence has revealed the vital regulatory roles of lncRNA DLX6-AS1 in various tumors at pre-transcriptional, transcriptional, and post-transcriptional levels, which makes it a potential prognosis factor and therapeutic target. In addition, the presence of lncRNA DLX6-AS1 in the exosomes of peripheral blood of patients with tumors may also contribute to it being a possible cancer-related biomarker. However, most literature studies are devoted to studying the effect of lncRNA DLX6-AS1 as a sponging molecule of miRNAs, the research of which is likely to get stuck into a dilemma. Literature studies published already have demonstrated an exciting cell malignant phenotype inhibition with the knockdown of lncRNA DLX6-AS1 in various tumor cell lines. With the comprehensive development of delivery systems, high-throughput sequencing, and aptamers, the problems of finding novel research methods and exploring the therapeutic options which are based on lncRNA DLX6-AS1 in vivo could come into a period to deal with. This review aims to summarize the research statuses of lncRNA DLX6-AS1, discuss other study methodologies and therapeutic strategies on it, which might be of help to the deep learning of lncRNA DLX6-AS1 and its application from basic to clinical research.

Persistent Properties of a Subpopulation of Cancer Cells Overexpressing the Hedgehog Receptor Patched

Despite the development of new therapeutic strategies, cancer remains one of the leading causes of mortality worldwide. One of the current major challenges is the resistance of cancers to chemotherapy treatments inducing metastases and relapse of the tumor. The Hedgehog receptor Patched (Ptch1) is overexpressed in many types of cancers. We showed that Ptch1 contributes to the efflux of doxorubicin and plays an important role in the resistance to chemotherapy in adrenocortical carcinoma (ACC), a rare cancer which presents strong resistance to the standard of care chemotherapy treatment. In the present study, we isolated and characterized a subpopulation of the ACC cell line H295R in which Ptch1 is overexpressed and more present at the cell surface. This cell subpopulation is more resistant to doxorubicin, grows as spheroids, and has a greater capability of clonogenicity, migration, and invasion than the parental cells. Xenograft experiments performed in mice and in ovo showed that this cell subpopulation is more tumorigenic and metastatic than the parental cells. These results suggest that this cell subpopulation has cancer stem-like or persistent cell properties which were strengthened by RNA-seq. If present in tumors from ACC patients, these cells could be responsible for therapy resistance, relapse, and metastases.

DLX6-AS1: A Long Non-coding RNA With Oncogenic Features

Long non-coding RNAs (lncRNAs) are a heterogeneous group of ncRNAs with characteristic size of more than 200 nucleotides. An increasing number of lncRNAs have been found to be dysregulated in many human diseases particularly cancer. However, their role in carcinogenesis is not precisely understood. DLX6-AS1 is an lncRNAs which has been unveiled to be up-regulated in various number of cancers. In different cell studies, DLX6-AS1 has shown oncogenic role via promoting oncogenic phenotype of cancer cell lines. Increase in tumor cell proliferation, migration, invasion, and EMT while suppressing apoptosis in cancer cells are the effects of DLX6-AS1 in development and progression of cancer. In the majority of cell experiment, mediator miRNAs have been identified which are sponged and negatively regulated by DLX6-AS1, and they in turn regulate expression of a number of transcription factors, eventually affecting signaling pathways involved in carcinogenesis. These pathways form axes through which DLX6-AS1 promotes carcinogenicity of cancer cells. Xenograft animal studies, also have confirmed enhancing effect of DLX6-AS1 on tumor growth and metastasis. Clinical evaluations in cancerous patients have also shown increased expression of DLX6-AS1 in tumor tissues compared to healthy tissues. High DLX6-AS1 expression has shown positive association with advanced clinicopathological features in cancerous patients. Survival analyses have demonstrated correlation between high DLX6-AS1 expression and shorter survival. In cox regression analysis, DLX6-AS1 has been found as an independent prognostic factor for patients with various types of cancer.

GTF2E2 is a novel biomarker for recurrence after surgery and promotes progression of esophageal squamous cell carcinoma via miR-139-5p/GTF2E2/FUS axis

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal gastrointestinal malignancies with high mortality. Recurrence develops within only a few years after curative resection and perioperative adjuvant therapy in 30-50% of these patients. Therefore, it is essential to identify postoperative recurrence biomarkers to facilitate selecting the following surveillance and therapeutic strategies. The general transcription factor IIE subunit beta (GTF2E2) is crucial for physiological and pathological functions, but its roles in the aggression and recurrence of ESCC remain ambiguous. In this study, we found that GTF2E2 was highly expressed in ESCC samples, and elevated GTF2E2 expression predicted early recurrence after surgery for ESCC patients. High expression of GTF2E2 associated with more aggressive clinic features and poor prognosis. GTF2E2 promoted the proliferation and mobility of ESCC cells in vitro and in vivo. We further revealed that miR-139-5p repressed GTF2E2 expression by downregulating its mRNA through binding with Argonaute 2 (Ago2). Rescue assays suggested that miR-139-5p affected GTF2E2-mediated ESCC progression. Moreover, GTF2E2 positively interacted with FUS promoter and regulated FUS expression, and the phenotype changes caused by GTF2E2 manipulation were recovered by rescuing FUS expression in ESCC cells. Additionally, we demonstrated that GTF2E2 promotes ESCC cells progression via activation of the AKT/ERK/mTOR pathway. In conclusion, GTF2E2 may serve as a novel biomarker for recurrence after surgery and a potential therapeutic target for ESCC patients, and it promotes ESCC progression via miR-139-5p/GTF2E2/FUS axis.

DLX6-AS1: a putative lncRNA candidate in multiple human cancers

Long non-coding RNAs (lncRNAs) have important roles in regulating the expression of genes and act as biomarkers in the initial development of different cancers. Increasing research studies have verified that dysregulation of lncRNAs occurs in various pathological processes including tumorigenesis and cancer progression. Among the different lncRNAs, DLX6-AS1 has been reported to act as an oncogene in the development and prognoses of different cancers, by affecting many different signalling pathways. This review summarises and analyses the recent research studies describing the biological functions of DLX6-AS1, its overall effect on signalling pathways and the molecular mechanisms underlying its action on the expression of genes in multiple human cancers. Our critical analysis suggests that different signalling pathways associated to this lncRNA may be used as a biomarker for diagnosis, or targets of treatment in cancers.

Research progress of DLX6-AS1 in human cancers

Long non-coding RNAs (lncRNAs) are a kind of translational-repressor RNAs composed of more than 200 nucleotides and formerly considered as "transcriptional noise". Recently studies have shown that lncRNAs could bind to multiple biomolecules such as DNA, transcription factors, RNA, chromatin complexes and proteins, and regulate target gene expression at multi-levels, thus playing an essential role in human tumors. DLX6-AS1, a recently discovered oncogenic lncRNA, is highly expressed in various human tumors, including lung cancer, liver cancer and pancreatic cancer. This paper mainly reviewed the regulatory mechanism of DLX6-AS1 as a competitive endogenous RNA (ceRNA) in tumor cell proliferation, cell apoptosis, angiogenesis, epithelial-mesenchymal transformation, chemotherapy resistance and metabolic changes. Furthermore, the translational value of DLX6-AS1 in cancer was also elucidated, which suggested its potential as a diagnostic or prognostic biomarker in cancer. In summary, this present article not only makes an in-depth analysis of the expression changes and carcinogenic mechanism of DLX6-AS1 in various human cancers, but also provides a new breakthrough for the diagnosis and treatment of cancers.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

DLX6-AS1: An Indispensable Cancer-related Long Non-coding RNA

BACKGROUND

There is increasing evidence that lncRNA, a type of transcript that is over 200 nucleotides in length and may serve as oncogenes or suppressor genes, is implicated in the pathophysiology of human diseases. In particular, tumorigenesis and progress are closely correlated with its abnormal expression. In addition, it may become a promising target for many oncology biotherapies. Abnormal DLX6-AS1 expression affects different cellular processes such as proliferation, aggression and metastasis. This review aims to probe into the pathophysiological functions and molecular mechanisms of DLX6-AS1 in various cancers.

METHODS

By retrieving the literature, this review summarizes the biological function and mechanism of LncRNA DLX6-AS1 in tumor occurrence.

RESULTS

The lncRNA DLX6-AS1 is a new tumor-related RNA that has recently been found to be aberrantly expressed in diverse cancers, such as pancreatic cancer, osteosarcoma, non-small cell lung cancer, gastric carcinoma, glioma, hepatocellular cancer, colorectal carcinoma, renal carcinoma, esophageal squamous cell cancer, ovarian cancer, Ewing sarcoma, cervical cancer, breast cancer, thyroid cancer, neuroblastoma, pulmonary adenocarcinoma, nasopharyngeal carcinoma, squamous laryngeal cancer and bladder cancer, etc. Meanwhile, it is identified that DLX6-AS1 regulates the aggression, translocation and proliferation of diverse cancers.

CONCLUSION

LncRNA DLX6-AS1 may be viable markers in tumors or a potential therapeutic target for multiple tumors.

The Multifaceted Role of Long Non-Coding RNA in Gastric Cancer: Current Status and Future Perspectives

Gastric cancer (GC) is one of the major public health concerns. Long non-coding RNAs (lncRNAs) have been increasingly demonstrated to possess a strong correlation with GC and play a critical role in GC occurrence, progression, metastasis and drug resistance. Many studies have shed light on the understanding of the underlying mechanisms of lncRNAs in GC. In this review, we summarized the updated research about lncRNAs in GC, focusing on their roles in Helicobacter pylori infection, GC metastasis, tumor microenvironment regulation, drug resistance and associated signaling pathways. LncRNAs may serve as novel biomarkers for diagnosis and prognosis of GC and potential therapeutic targets. The research gaps and future directions were also discussed.

The Impact of Non-coding RNAs in the Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is a course of action that enables a polarized epithelial cell to undertake numerous biochemical alterations that allow it to adopt features of mesenchymal cells such as high migratory ability, invasive properties, resistance to apoptosis, and importantly higher-order formation of extracellular matrix elements. EMT has important roles in implantation and gastrulation of the embryo, inflammatory reactions and fibrosis, and transformation of cancer cells, their invasiveness and metastatic ability. Regarding the importance of EMT in the invasive progression of cancer, this process has been well studies in in this context. Non-coding RNAs (ncRNAs) have been shown to exert critical function in the regulation of cellular processes that are involved in the EMT. These processes include regulation of some transcription factors namely SNAI1 and SNAI2, ZEB1 and ZEB2, Twist, and E12/E47, modulation of chromatin configuration, alternative splicing, and protein stability and subcellular location of proteins. In the present paper, we describe the influence of ncRNAs including microRNAs and long non-coding RNAs in the EMT process and their application as biomarkers for this process and cancer progression and their potential as therapeutic targets.

DLX6-AS1 is a potential biomarker and therapeutic target in cancer initiation and progression

Long noncoding RNAs (lncRNAs) are involved in multiple functions such as the regulation of cellular homeostasis. They play prominent roles in the pathogenesis of human cancer, and contribute to every hallmark of cancer. The novel cancer-related lncRNA DLX6 antisense RNA 1 (DLX6-AS1) plays an essential regulatory role in enhancing and initiating carcinogenesis and tumor progression. This progression is due to the aberrant regulation of downstream factors in vitro as well as in vivo. DLX6-AS1 is significantly dysregulated in various cancers. DLX6-AS1 functions in tumor initiation and progression are regulated at the epigenetic, transcription, and posttranscriptional regulation levels. DLX6-AS1 functions as an oncogene, binding to miRNA targeting sites competing endogenous RNAs and causing the upregulation of downstream tumor-related genes and carcinogenesis. The regulation and detailed molecular mechanisms of DLX6-AS1 and its potential role in malignancies are comprehensively described in this paper. DLX6-AS1 has the potential to become a novel biomarker and therapeutic target for cancer.

Serum Exosomal lncRNA DLX6-AS1 Is a Promising Biomarker for Prognosis Prediction of Cervical Cancer

OBJECTIVE

Deregulation of long noncoding RNAs (lncRNAs) is involved in the initiation and progression of cancer. LncRNA DLX6-AS1 is regarded as an oncogene in many cancer types. However, the clinical role of serum exosomal lncRNA DLX6-AS1 in cervical cancer (CC) is poorly known. This study aimed to analyze the diagnostic and prognostic value of serum exosomal lncRNA DLX6-AS1 in CC.

METHODS

A total of 114 patients with CC, 60 patients with CIN (cervical intraepithelial neoplasia), and 110 healthy women were enrolled in this study. Real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to measure the serum exosomal lncRNA DLX6-AS1 levels in all participants.

RESULTS

Serum exosomal lncRNA DLX6-AS1 level was significantly elevated in CC patients compared with CIN patients and normal controls. In addition, high serum exosomal lncRNA DLX6-AS1 expression was positively associated with lymph node metastasis, differentiation, FIGO stage, and shortened survival. Patients with high serum exosomal lncRNA DLX6-AS1 expression were more prone to have a relapse. Furthermore, univariate and multivariate analyses suggested that serum exosomal lncRNA DLX6-AS1 was a potential prognostic indicator for overall survival of CC patients.

CONCLUSIONS

These findings demonstrated that serum lncRNA DLX6-AS1 might serve as a promising marker for the diagnosis and prognosis prediction of CC.

Roles and Mechanisms of the Long Noncoding RNAs in Cervical Cancer

Cervical cancer (CC) continues to be one of the leading causes of death for women across the world. Although it has been determined that papillomavirus infection is one of the main causes of the etiology of the disease, genetic and epigenetic factors are also required for its progression. Among the epigenetic factors are included the long noncoding RNAs (lncRNAs), transcripts of more than 200 nucleotides (nt) that generally do not code for proteins and have been associated with diverse functions such as the regulation of transcription, translation, RNA metabolism, as well as stem cell maintenance and differentiation, cell autophagy and apoptosis. Recently, studies have begun to characterize the aberrant regulation of lncRNAs in CC cells and tissues, including Homeobox transcript antisense RNA (HOTAIR), H19, Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), Cervical Carcinoma High-Expressed 1 (CCHE1), Antisense noncoding RNA in the inhibitors of cyclin-dependent kinase 4 (ANRIL), Growth arrest special 5 (GAS5) and Plasmacytoma variant translocation 1 (PVT1). They have been associated with several disease-related processes such as cell growth, cell proliferation, cell survival, metastasis and invasion as well as therapeutic resistance, and are novel potential biomarkers for diagnosis and prognosis in CC. In this review, we summarize the current literature regarding the knowledge we have about the roles and mechanisms of the lncRNAs in cervical neoplasia.

Promising long noncoding RNA DLX6-AS1 in malignant tumors

Although its diagnosis and treatment have greatly improved in recent decades, cancer remains the major cause of death worldwide. Thus, there is an urgent need to find novel biomarkers and therapeutic targets to improve efficiency of diagnosis and treatment of patients with cancer. Long noncoding RNAs (lncRNAs), a new class of noncoding RNAs (ncRNAs), have been found to play a salient role in human tumorigenesis and progression. Distal-less homeobox 6 antisense RNA 1 (DLX6-AS1) is a novel lncRNA with aberrant expression in various cancers tissues and cell lines compared with nontumor tissues and normal cell lines. Importantly, DLX6-AS1 is closely associated with tumor cell proliferation, apoptosis, invasion, and migration. Patients with high DLX6-AS1 expression often had poorer prognosis than those with low expression. The oncogenicity of DLX6-AS1 mainly (indirectly or indirectly) interacts with targeting genes, and then regulates downstream genes and signaling pathways. Together with the findings of animal model studies, these data suggest that DLX6-AS1 may serve as a feasible predictor or therapeutic target in different cancers. Herein, we summarize the main findings concerning the function and molecular mechanisms of DLX6-AS1 to identify a molecular basis for future clinical application.

Crosstalk between long non-coding RNA DLX6-AS1, microRNAs and signaling pathways: A pivotal molecular mechanism in human cancers

Long non-coding RNAs (lncRNAs) are a type of non-protein coding RNA, which have been found to play multiple roles in various molecular and cellular processes by epigenetic regulation of gene expression at post transcriptional levels. LncRNAs may act either as an oncogene or as a tumor suppressor gene in different cancers. Aberrant expression and dysregulation of lncRNAs has been correlated with cancer development and tumor growth via several different signaling pathways. Therefore, lncRNAs could serve as diagnostic biomarkers and as therapeutic targetes in many human cancers. Previous studies have reported that dysregulated expression of the lncRNA called DLX6-AS1 in various cancer types, such as lung, colorectal, bladder, ovarian, hepatocellular, pancreatic and gastric. DLX6-AS1 plays an important role in tumorigenesis by affecting cell proliferation, migration, invasion, EMT, and apoptosis. DLX6-AS1 exerts these regulatory effects by interfering with various microRNA axes and signaling pathways including, Wnt/βcatenin, Notch, P13/AKT/mTOR, and STAT3. This review focuses on the possible mechanisms by which DLX6-AS1 regulates tumor initiation and progression. Accordingly, DLX6-AS1 may act as a novel potential biomarker for cancer diagnosis or therapy in future.

LncRNA DLX6-AS1 Promotes Malignant Phenotype and Lymph Node Metastasis in Prostate Cancer by Inducing LARGE Methylation

Long non-coding RNAs (lncRNAs) have recently become recognized as crucial players in cancer cellular events including proliferation, migration, and invasion. Herein, we investigated the potential role of lncRNA DLX6-AS1 in prostate cancer cell malignant behaviors and lymph node metastasis. A differentially expressed lncRNA DLX6-AS1 and its downstream regulatory gene (LARGE) were predicted by analysis in silico. RT-qPCR and western blot analysis results demonstrated that DLX6-AS1 was highly expressed, but LARGE was poorly expressed in prostate cancer tissues and cells. The online website indicated that DLX6-AS1 negatively targeted LARGE expression, which was validated by Pearson correlation analysis and MSP. ChIP, RIP, and RNA pull-down assays further suggested that DLX6-AS1 downregulated LARGE expression through recruitment of DNMT1 to its promoter. We induced DLX6-AS1/LARGE overexpression or knockdown to examine their effects through Edu and Transwell assays, which revealed that DLX6-AS1 overexpression accelerated proliferation, invasion, and migration of prostate cancer cells, and that overexpression of LARGE rescued these effects. Tumors xenografts studies confirmed that DLX6-AS1 promoted lymph node metastasis by regulating LARGE, as evidenced by enhanced expression of MMP-9, uPAR, and cathepsin B. In summary, DLX6-AS1 stimulated prostate cancer malignant progression and lymph node metastasis by inducing DNMT1-mediated LARGE methylation, highlighting a potential therapeutic target against prostate cancer.

LncRNA EMX2OS, Regulated by TCF12, Interacts with FUS to Regulate the Proliferation, Migration and Invasion of Prostate Cancer Cells Through the cGMP-PKG Signaling Pathway

Background

LncRNA EMX2OS (EMX2 opposite strand/antisense RNA) is notably downregulated in prostate cancer (PCa) tissues and may be regarded as a potential molecular biomarker for diagnosis and prognosis. However, its exact role in regulating the development of PCa is obscure.

Methods

The EMX2OS expression was assessed in PCa tissues, paracancer tissues, PCa cells and normal prostate epithelial cells by qPCR. Gain- and loss-of-function experiments were performed to investigate the role of EMX2OS and FUS in cGMP-PKG (cyclic guanosine monophosphate-dependent protein kinase)-mediated proliferation, invasion, and migration in human PCa cell lines DU145 and PC3. Then, the interaction of transcription factor 12 (TCF12) with EMX2OS promoter was confirmed by using the dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays. RNA binding protein immunoprecipitation and RNA pull-down assays were used to verify the interaction between EMX2OS and FUS protein. Finally, the role of EMX2OS and FUS in tumor growth in vivo was validated in a xenograft nude mouse model.

Results

TCF12 and EMX2OS were both downregulated in PCa tissues and cells, and they negatively regulated cell proliferation, migration and invasion, and activated cGMP-PKG pathway in DU145 and PC3 cells. TCF12 was a transcription factor of EMX2OS. TCF12 and EMX2OS overexpression both down-regulated cell proliferation, migration and invasion, and activated cGMP-PKG pathway in DU145 and PC3 cells. Furthermore, EMX2OS directly bound with FUS protein and had a synergy effect with FUS protein on cGMP-PKG-mediated cell functions, which could be suppressed by (D)-DT-2 (a cGMP-PKG inhibitor). In addition, the overexpression of FUS or EMX2OS individually markedly decreased the volume and weight of tumors in vivo, and co-overexpression of them further inhibited tumor growth.

Conclusion

EMX2OS, transcriptionally regulated by TCF12, played a synergy role with FUS protein in regulating the proliferation, migration and invasion of PCa cells by activating the cGMP-PKG pathway.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

lncRNA DLX6-AS1 Promotes Proliferation of Laryngeal Cancer Cells by Targeting the miR-26a/TRPC3 Pathway

Purpose

Laryngeal cancer is the most prevalent tumor type in head and neck cancers. Early diagnosis is considered as an important strategy for improving prognosis. The lncRNA DLX6-AS1 has been shown to modulate tumor phenotypes in several types of cancer, but the role of DLX6-AS1 in laryngeal cancer and its concrete mechanisms are not clear.

Methods

Tissue samples from laryngeal cancer patients and corresponding clinical data were used for detailed analysis. The laryngeal cancer cell lines HEp-2 and Tu-177 were studied. Cell proliferation, ROS production, mitochondrial respiratory function, intracellular and mitochondrial calcium influx were assessed. Western blotting, quantitative RT-PCR and luciferase assays were used to analyze the interactions. A xenografted tumor model was established to analyze the effects of DLX6-AS1 on tumor growth in vivo.

Results

lncRNA DLX6-AS1 had increased expression in tumor tissues compared with adjacent normal tissues and in higher clinical stages compared with lower stages, which was associated with poor prognosis. In detail, DLX6-AS1 knockdown decreased cell proliferation and affected key mitochondrial metabolic parameters in both HEp-2 and Tu-177 cells. Moreover, DLX6-AS1 knockdown suppressed TRPC3-mediated mitochondrial calcium uptake and ROS production. Furthermore, miR-26a functioned as a link between these two molecules, as it could be absorbed by DLX6-AS1 and thus regulated the levels of TRPC3. Finally, the DLX6-AS1/miR-26a/TRPC3 axis modulated laryngeal cancer proliferation both in vitro and in vivo.

Conclusion

This study provides new evidence that a novel lncRNA, DLX6-AS1, regulates mitochondrial calcium homeostasis, respiration and tumor proliferation via modulating the miR-26a/TRPC3 axis in laryngeal cancer.

The lncRNA DLX6-AS1 promoted cell proliferation, invasion, migration and epithelial-to-mesenchymal transition in bladder cancer via modulating Wnt/β-catenin signaling pathway

Background

Bladder cancer is the most common human urological malignancies with poor prognosis, and the pathophysiology of bladder cancer involves multi-linkages of regulatory networks in the bladder cancer cells. Recently, the long noncoding RNAs (lncRNAs) have been extensively studied for their role on bladder cancer progression. In this study, we evaluated the expression of DLX6 Antisense RNA 1 (DLX6-AS1) in the cancerous bladder tissues and studied the possible mechanisms of DLX6-AS1 in regulating bladder cancer progression.

Methods

Gene expression was determined by qRT-PCR; protein expression levels were evaluated by western blot assay; in vitro functional assays were used to determine cell proliferation, invasion and migration; nude mice were used to establish the tumor xenograft model.

Results

Our results showed the up-regulation of DLX6-AS1 in cancerous bladder cancer tissues and bladder cell lines, and high expression of DLX6-AS1 was correlated with advance TNM stage, lymphatic node metastasis and distant metastasis. The in vitro experimental data showed that DLX6-AS1 overexpression promoted bladder cancer cell growth, proliferation, invasion, migration and epithelial-to-mesenchymal transition (EMT); while DLX6-AS1 inhibition exerted tumor suppressive actions on bladder cancer cells. Further results showed that DLX6-AS1 overexpression increased the activity of Wnt/β-catenin signaling, and the oncogenic role of DLX6-AS1 in bladder cancer cells was abolished by the presence of XAV939. On the other hand, DLX6-AS1 knockdown suppressed the activity of Wnt/β-catenin signaling, and the tumor-suppressive effects of DLX6-AS1 knockdown partially attenuated by lithium chloride and SB-216763 pretreatment. The in vivo tumor growth study showed that DLX6-AS1 knockdown suppressed tumor growth of T24 cells and suppressed EMT and Wnt/β-catenin signaling in the tumor tissues.

Conclusion

Collectively, the present study for the first time identified the up-regulation of DLX6-AS1 in clinical bladder cancer tissues and in bladder cancer cell lines. The results from in vitro and in vivo assays implied that DLX6-AS1 exerted enhanced effects on bladder cancer cell proliferation, invasion and migration partly via modulating EMT and the activity of Wnt/β-catenin signaling pathway.