lncRNA GAS5 Reverses EMT and Tumor Stem Cell-Mediated Gemcitabine Resistance and Metastasis by Targeting miR-221/SOCS3 in Pancreatic Cancer

LncRNA MAGI2-AS3 Is Regulated by BRD4 and Promotes Gastric Cancer Progression via Maintaining ZEB1 Overexpression by Sponging miR-141/200a

Long non-coding RNAs (lncRNAs) play critical roles in tumorigenesis and tumor progression. However, the biological function of most lncRNAs remains unknown in human gastric cancer. This study here aims to explore the unknown function of lncRNA MAGI2-AS3 in gastric cancer. First, bioinformatics analysis showed that lncRNA MAGI2-AS3 was overexpressed in gastric cancer tissues, and the overexpression of MAGI2-AS3 has been shown to be associated with poor prognosis in all three independent gastric cancer cohorts (The Cancer Genome Atlas stomach cancer [TCGA_STAD], GEO: GSE62254 and GSE15459). The multivariate analysis indicated that lncRNA MAGI2-AS3 was an independent prognostic factor for both overall survival and disease-free survival of gastric cancer patients. Moreover, MAGI2-AS3 was identified to be an epithelial-mesenchymal transition (EMT)-related lncRNA and was highly co-expressed with ZEB1/2 in both gastric cancer tissues and normal stomach tissues. Loss-of-function and gain-of-function studies showed that lncRNA MAGI2-AS3 could positively regulate ZEB1 expression and the process of cell migration and invasion in gastric cancer. Subcellular location assay showed that lncRNA MAGI2-AS3 was mainly located in the cytoplasm of gastric cancer cells. Bioinformatics analysis and functional experiments revealed that lncRNA MAGI2-AS3 was negatively correlated with miR-141/200a expression and negatively regulated miR-141/200a-3p expression in gastric cancer. Therefore, we speculate that lncRNA MAGI2-AS3 promotes tumor progression through sponging miR-141/200a and maintaining overexpression of ZEB1 in gastric cancer. Nevertheless, we identified that BRD4 is a transcriptional regulator of lncRNA MAGI2-AS3 in gastric cancer. Additionally, our findings highlight that lncRNA MAGI2-AS3 is an ideal biomarker and could be a potential therapeutic target for gastric cancer.

Long non-coding RNA GAS5 inhibits migration and invasion in gastric cancer via interacting with p53 protein

BACKGROUND

The rapid progress of gastric cancer (GC) is mainly due to metastasis. Long non-coding RNA (lncRNA) GAS5 has been identified as a tumor suppressor in numerous cancers, and its downregulation in GC has already been reported.

AIMS

In this study, we planned to investigate the role of GAS5 in GC metastasis.

METHODS

Gene expressions were detected by qRT-PCR. ISH staining was applied to assess GAS5 level in clinical tissues. Gain-of-function assays were conducted to evaluate the function of GAS5 in GC metastasis. RNA pull down, RIP and cycloheximide assays were performed to confirm the relationship between GAS5 and p53 protein.

RESULTS

GAS5 expression was markedly decreased in GC tissues and cell lines, and its low expression was strongly related to GC metastasis and unsatisfactory prognosis. GAS5 overexpression repressed GC cell migration and invasion by targeting p53. Intriguingly, GAS5 relied on the exon 12 to interact with and stabilize p53 protein.

CONCLUSION

Our data implied that GAS5 is a suppressor in GC metastasis via modulating p53 signaling, suggesting GAS5 as a potential therapeutic target for GC, especially for patients with metastasis.

The multifaceted roles of long noncoding RNAs in pancreatic cancer: an update on what we know

Pancreatic cancer (PC) is one of the leading causes of cancer-related deaths worldwide. Due to the shortage of effective biomarkers for predicting survival and diagnosing PC, the underlying mechanism is still intensively investigated but poorly understood. Long noncoding RNAs (lncRNAs) provide biological functional diversity and complexity in protein regulatory networks. Scientific studies have revealed the emerging functions and regulatory roles of lncRNAs in PC behaviors. It is worth noting that some in-depth studies have revealed that lncRNAs are significantly associated with the initiation and progression of PC. As lncRNAs have good properties for both diagnostic and prognostic prediction due to their translation potential, we herein address the current understanding of the multifaceted roles of lncRNAs as regulators in the molecular mechanism of PC. We also discuss the possibility of using lncRNAs as survival biomarkers and their contributions to the development of targeted therapies based on the literature. The present review, based on what we know about current research findings, may help us better understand the roles of lncRNAs in PC.

Upregulation of hsa_circ_0007874 suppresses the progression of ovarian cancer by regulating the miR-760/SOCS3 pathway

Ovarian cancer (OVA) is a fatal and common malignancy in women worldwide. Circular RNAs (circRNAs) consist of a family of circular endogenous RNAs generated by selective splicing, and they are involved in many diseases. Previous studies reported that hsa_circ_0007874 is aberrantly expressed in cancer and functions in tumorigenesis. While the hsa_circ_0007874 role in OVA is unclear. Here, we detected the hsa_circ_0007874 expression in OVA cell lines using Rt‐qPCR. Hsa_circ_0007874 subcellular localization was confirmed by fluorescence in situ hybridization. The relationship between hsa_circ_0007874, microRNAs (miRNAs), and relative protein levels was assessed using the luciferase reporter assays. Results verified that hsa_circ_0007874 is downregulated in OVA cell lines. hsa_circ_0007874 overexpression decreased the OVA cell migration and proliferation in vitro and in vivo. Bioinformatics and luciferase reporter assays confirmed that miR‐760 and SOCS3 are the downstream targets of hsa_circ_0007874. Downregulation of SOCS3 or miR‐760 overexpression restored the migration and proliferation ability of SKOV3 or A2780 cells overexpressing hsa_circ_0007874. Downregulation of SOCS3 restored the proliferation and migration in miR‐760 knockdown SKOV3 and A2780 cells. In summary, the data suggest that hsa_circ_0007874 acts as a tumor suppressor by regulating the miR‐760/SOCS3 axis, highlighting its potential as an effective therapeutic target for OVA.

The lncRNA-GAS5/miR-221-3p/DKK2 Axis Modulates ABCB1-Mediated Adriamycin Resistance of Breast Cancer via the Wnt/β-Catenin Signaling Pathway

Drug resistance, including adriamycin (ADR)-based therapeutic resistance, is a crucial cause of chemotherapy failure in breast cancer treatment. Acquired chemoresistance has been identified to be closely associated with the overexpression of P-glycoprotein (P-gp/ABCB1). Long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) can be involved in carcinogenesis; however, its roles in ABCB1-mediated ADR resistance are poorly understood. In this study, we identified a panel of differentially expressed lncRNAs, mRNAs, and microRNAs (miRNAs) in MCF-7 and MCF-7/ADR cell lines through RNA sequencing (RNA-seq) technologies. GAS5 level was downregulated whereas ABCB1 level was upregulated in the resistant breast cancer tissues and cells. Overexpression of GAS5 significantly enhanced the ADR sensitivity and apoptosis, and it inhibited the efflux function and expression of ABCB1 in vitro, while knockdown of GAS5 had the opposite effects. Further mechanism-related investigations indicated that GAS5 acted as an endogenous “sponge” by competing for miR-221-3p binding to regulate its target dickkopf 2 (DKK2), and then it inhibited the activation of the Wnt/β-catenin pathway. Functionally, GAS5 enhanced the anti-tumor effect of ADR in vivo. Collectively, our findings reveal that GAS5 exerted regulatory function in ADR resistance possibly through the miR-221-3p/DKK2 axis, providing a novel approach to develop promising therapeutic strategy for overcoming chemoresistance in breast cancer patients.

The genetic script of metastasis

Metastasis is a pivotal event that changes the course of cancers from benign and treatable to malignant and difficult to treat, resulting in the demise of patients. Understanding the genetic control of metastasis is thus crucial to develop efficient and sustainable targeted therapies. Here we discuss the alterations in epigenetic mechanisms, transcription, chromosomal instability, chromosome imprinting, non-coding RNAs, coding RNAs, mutant RNAs, enhancers, G-quadruplexes, and copy number variation to dissect the genetic control of metastasis. We conclude that the genetic control of metastasis is predominantly executed through epithelial to mesenchymal transition and evasion of cell death. We discuss how genetic regulatory mechanisms can be harnessed for therapeutic purposes to achieve sustainable control over cancer metastasis.

MiRNAs as Novel Adipokines: Obesity-Related Circulating MiRNAs Influence Chemosensitivity in Cancer Patients

Adipose tissue is an endocrine organ, capable of regulating distant physiological processes in other tissues via the release of adipokines into the bloodstream. Recently, circulating adipose-derived microRNAs (miRNAs) have been proposed as a novel class of adipokine, due to their capacity to regulate gene expression in tissues other than fat. Circulating levels of adipokines are known to be altered in obese individuals compared with typical weight individuals and are linked to poorer health outcomes. For example, obese individuals are known to be more prone to the development of some cancers, and less likely to achieve event-free survival following chemotherapy. The purpose of this review was twofold; first to identify circulating miRNAs which are reproducibly altered in obesity, and secondly to identify mechanisms by which these obesity-linked miRNAs might influence the sensitivity of tumors to treatment. We identified 8 candidate circulating miRNAs with altered levels in obese individuals (6 increased, 2 decreased). A second literature review was then performed to investigate if these candidates might have a role in mediating resistance to cancer treatment. All of the circulating miRNAs identified were capable of mediating responses to cancer treatment at the cellular level, and so this review provides novel insights which can be used by future studies which aim to improve obese patient outcomes.

The interplay between m6A RNA methylation and noncoding RNA in cancer

N6-methyladenosine (m6A) methylation, one of the most common RNA modifications, has been reported to execute important functions that affect normal life activities and diseases. Most studies have suggested that m6A modification can affect the complexity of cancer progression by regulating biological functions related to cancer. M6A modification of noncoding RNAs regulates the cleavage, transport, stability, and degradation of noncoding RNAs themselves. It also regulates cell proliferation and metastasis, stem cell differentiation, and homeostasis in cancer by affecting the biological function of cells. Interestingly, noncoding RNAs also play significant roles in regulating these m6A modifications. Additionally, it is becoming increasingly clear that m6A and noncoding RNAs potentially contribute to the clinical application of cancer treatment. In this review, we summarize the effect of the interactions between m6A modifications and noncoding RNAs on the biological functions involved in cancer progression. In particular, we discuss the role of m6A and noncoding RNAs as possible potential biomarkers and therapeutic targets in the treatment of cancers.

Long non-coding RNA GAS5 acts as proliferation "brakes" in CD133+ cells responsible for tumor recurrence

Presence of quiescent, therapy evasive population often described as cancer stem cells (CSC) or tumor initiating cells (TIC) is often attributed to extreme metastasis and tumor recurrence. This population is typically enriched in a tumor as a result of microenvironment or chemotherapy induced stress. The TIC population adapts to this stress by turning on cell cycle arrest programs that is a “fail-safe” mechanism to prevent expansion of malignant cells to prevent further injury. Upon removal of the “stress” conditions, these cells restart their cell cycle and regain their proliferative nature thereby resulting in tumor relapse. Growth Arrest Specific 5 (GAS5) is a long-non-coding RNA that plays a vital role in this process. In pancreatic cancer, CD133+ population is a typical representation of the TIC population that is responsible for tumor relapse. In this study, we show for the first time that emergence of CD133+ population coincides with upregulation of GAS5, that reprograms the cell cycle to slow proliferation by inhibiting GR mediated cell cycle control. The CD133+ population further routed metabolites like glucose to shunt pathways like pentose phosphate pathway, that were predominantly biosynthetic in spite of being quiescent in nature but did not use it immediately for nucleic acid synthesis. Upon inhibiting GAS5, these cells were released from their growth arrest and restarted the nucleic acid synthesis and proliferation. Our study thus showed that GAS5 acts as a molecular switch for regulating quiescence and growth arrest in CD133+ population, that is responsible for aggressive biology of pancreatic tumors.

LncRNA SNHG16 induces the SREBP2 to promote lipogenesis and enhance the progression of pancreatic cancer

Aim: Blocking lipogenesis could significantly inhibit the progression of pancreatic cancer. Exploring the regulatory mechanisms of lipogenesis by lncRNA SNHG16 might be of great significance to control the development of pancreatic cancer. Methods: The proliferation, migration, invasion and lipogenesis were determined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, transwell and Oil Red O staining assays, respectively. The interactions among lncRNA SNHG16, miR-195 and SREBP2 were analyzed by dual luciferase reporter assays. Results: Both the knock down of lncRNA SNHG16 and SREBP2 and overexpression of miR-195 suppressed the proliferation, migration, invasion and lipogenesis in pancreatic cancer cells. LncRNA SNHG16 directly sponged miR-195 to modulate the lipogenesis via regulating the expression of SREBP2. Conclusion: LncRNA SNHG16 accelerated the development of pancreatic cancer and promoted lipogenesis via directly regulating miR-195/SREBP2 axis.

Novel Tumor Suppressor lncRNA Growth Arrest-Specific 5 (GAS5) In Human Cancer

Long noncoding RNAs (lncRNAs) play crucial regulatory roles in fundamental biological processes, and deregulations of lncRNAs have been linked to numerous human diseases, especially cancers. Of particular interest in this regard is lncRNA GAS5, which is mainly identified as a tumor suppressor in several cancers. GAS5 was significantly low expressed in multiple cancers and was associated with clinic-pathological characteristics and patient survival, indicating a novel potential diagnostic and prognostic biomarker, and a therapeutic target for cancer. Functionally, GAS5 is involved in cell proliferation, metastasis, invasion, apoptosis, epithelial-mesenchymal transition (EMT), and drug resistance, among others, via multiple molecular mechanisms, such as binding to DNA sequences, forming RNA-DNA triplex complex, triggering or suppressing the expression of genes, binding proteins to form chromatin-modifying complex, which activates or represses gene expression, and acting as miRNA sponge to suppress miRNA expression, leading to regulation of miRNA target genes. This review provides an overview of the current state of knowledge and role of GAS5 in clinical relevance, biological functions and molecular mechanisms underlying the dysregulation of expression and function of GAS5 in cancer. Finally, the potential prospective role as diagnostic and prognostic biomarker and therapeutic target in cancer is discussed.

Long Noncoding RNA HCP5 Regulates Pancreatic Cancer Gemcitabine (GEM) Resistance By Sponging Hsa-miR-214-3p To Target HDGF

Background

Gemcitabine (GEM) is one of the most widely chemotherapy drugs in PC. However, the chemotherapy resistance always occurs after a period of treatment indicating poor prognosis. lncRNA may play an essential role in PC and serve as a prognosis biomarkers in PC with GEM-resistance. In our study, we aim to investigate the role of lncRNA HCP5 in PC.

Materials and methods

QRT-PCR detected the expression of lncRNA HCP5. The effects of knockdown lncRNA HCP5 on the proliferation, migration, invasion, cell apoptosis and autophagy were investigated in GEM-resistance PC cells. Bioinformatic analysis, luciferase reporter assay and RNA immunoprecipitation assay were performed to predict for potential miRNAs that can interact with lncRNA HCP5 and mRNAs that can interact with miR-214-3p.

Results

Our study revealed that lncRNA HCP5 expression was upregulated in PC tissues, especially increased expression in GEM-resistant PC tissues and GEM-resistant PC cells. Wound healing, Transwell assays, flow cytometry, Western blot, luciferase reporter assay and RNA immunoprecipitation (RIP) results demonstrated lncRNA HCP5 acted as a ceRNA to regulate GEM-resistance PC cells' proliferation, invasion, migration, cell apoptosis and autophagy by targeting HDGF via miR-214-3p.

Conclusion

Our results revealed that lncRNA HCP5 is highly expressed in HCC, and development of GEM-resistance PC cells involving the processes of proliferation, invasive, migration, cell apoptosis and autophagy through the miR-214-3p/HDGF axis. Targeting lncRNA HCP5 may improve gemcitabine-based therapeutic efficacy.

LncRNA GAS5 facilitates nasopharyngeal carcinoma progression through epigenetically silencing PTEN via EZH2

Increasing evidence demonstrated that long non-coding RNA growth-arrest-specific transcript 5 (GAS5) serves as a critical regulator in cancer development and progression. However, its function and mechanism in nasopharyngeal carcinoma (NPC) is still not well elucidated. In this study, we investigate the functional role as well as the molecular mechanism of GAS5 in NPC progression. Our results indicated that GAS5 expression was elevated in NPC tissues and cells. High GAS5 expression was correlated with poor prognosis of NPC patients. GAS5 knockdown suppressed proliferation, migration and invasion, and induced apoptosis in NPC cells. Moreover, GAS5 could epigenetically suppress PTEN expression via recruiting enhancer of zeste homolog 2 (EZH2). PTEN knockdown could reverse the inhibitory effect of GAS5 inhibition on NPC progression. Furthermore, GAS5 knockdown suppressed the tumor growth in vivo. In summary, knockdown of GAS5 repressed proliferation, migration and invasion, and promoted apoptosis in NPC through epigenetically silencing PTEN via recruiting EZH2.

Long noncoding RNA GSTM3TV2 upregulates LAT2 and OLR1 by competitively sponging let-7 to promote gemcitabine resistance in pancreatic cancer

BACKGROUND

Chemoresistance is one of the main causes of poor prognosis in pancreatic cancer patients. Understanding the mechanisms implicated in chemoresistance of pancreatic cancer is critical to improving patient outcomes. Recent evidences indicate that the long noncoding RNAs (lncRNAs) are involving in chemoresistance of pancreatic cancer. However, the mechanisms of lncRNAs contribute to resistance in pancreatic cancer and remain largely unknown. The objective of this study is to construct a chemoresistance-related lncRNA-associated competing endogenous RNA (ceRNA) network of pancreatic cancer and identify the key lncRNAs in regulating chemoresistance of the network.

METHODS

Firstly, lncRNA expression profiling of gemcitabine-resistant pancreatic cancer cells was performed to identify lncRNAs related to chemoresistance by microarray analysis. Secondly, with insights into the mechanism of ceRNA, we used a bioinformatics approach to construct a chemoresistance-related lncRNAs-associated ceRNA network. We then identified the topological key lncRNAs in the ceRNA network and demonstrated its function or mechanism in chemoresistance of pancreatic cancer using molecular biological methods. Further studies evaluated its expression to assess its potential association with survival in patients with pancreatic cancer.

RESULTS

Firstly, we demonstrated that lncRNAs were dysregulated in gemcitabine-resistant pancreatic cancer cells. We then constructed a chemoresistance-related lncRNA-associated ceRNA network and proposed that lncRNA Homo sapiens glutathione S-transferase mu 3, transcript variant 2 and noncoding RNA (GSTM3TV2; NCBI Reference Sequence: NR_024537.1) might act as a key ceRNA to enhance chemoresistance by upregulating L-type amino acid transporter 2 (LAT2) and oxidized low-density lipoprotein receptor 1(OLR1) in pancreatic cancer. Further studies demonstrated that GSTM3TV2, overexpressed in gemcitabine-resistant cells, enhanced the gemcitabine resistance of pancreatic cancer cells in vitro and in vivo. Mechanistically, we identified that GSTM3TV2 upregulated LAT2 and OLR1 by competitively sponging let-7 to promote gemcitabine resistance. In addition, we revealed that the expression levels of GSTM3TV2 were significantly increased in pancreatic cancer tissues and were associated with poor prognosis.

CONCLUSION

Our results suggest that GSTM3TV2 is a crucial oncogenic regulator involved in chemoresistance and could be a new therapeutic target or prognostic marker in pancreatic cancer.

Long non-coding RNA PXN-AS1 suppresses pancreatic cancer progression by acting as a competing endogenous RNA of miR-3064 to upregulate PIP4K2B expression

BACKGROUND

Dysregulation of microRNAs (miRNAs) play critical roles in cancerous processes. Although miR-3064 was reported to be an important tumor suppressor in ovarian cancer, the cellular impact of miR-3064 on pancreatic cancer (PC) progression, its downstream target genes and upstream mechanisms that control the expression of miR-3064 remain to be fully clarified.

METHODS

We compared miRNA expression profiles between PC tissues compared with normal tissues using a miRNA microarray analysis of clinical samples, and screened the identified miRNAs for their influence on cell proliferation. We measured the expression of miR-3064 in PC tissues and PC cell lines using quantitative real-time PCR assays. Gain- and loss-of-function experiments were conducted to explore the biologic significance of miR-3064 in PC progression both in vitro and in vivo. The interactions between miR-3064 and long noncoding RNA (lncRNA) PXN-AS1 was verified using the luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

We showed that miR-3064 was significantly overexpressed in PC tissues compared to normal tissues. High miR-3064 was associated with worse prognosis in patients with PC. Functionally, ectopic expression of miR-3064 promoted the proliferation, invasion, clone formation and sphere formation of PC cells in vitro and stimulated PC growth in vivo, while specific knockdown of miR-3064 or CRISPR/Cas9-mediated knockout of miR-3064 resulted in opposite phenotypes. Further investigation revealed that miR-3064 directly targeted PIP4K2B, which was reduced in PC tissues and attenuated PC cell proliferation, invasion and sphere formation induced by miR-3064. Importantly, lncRNA PXN-AS1 expression was downregulated in PC samples, and it directly interacted with miR-3064 and suppressed its levels in PC cells. Enforced expression of PXN-AS1 remarkably decreased cell proliferation, invasion and sphere formation, while re-expression of miR-3064 abrogated these effects of PXN-AS1.

CONCLUSIONS

MiR-3064, a key oncogenic miRNA, could promote PC cell growth, invasion and sphere formation via downregulating the levels of tumor suppressor PIP4K2B. PXN-AS1 functioned as a sponge to suppress the expression of miR-3064. These observations offer fresh insight into the mechanisms through which miR-3064 modulates the development of PC.

Long noncoding RNA GAS5-AS1 suppresses growth and metastasis of cervical cancer by increasing GAS5 stability

Cervical cancer (CC) is the second most common cancer and the fourth leading cause of cancer-related death in women worldwide. Up to date, only a few of long noncoding RNAs (lncRNAs) have been functionally characterized. Here, we aimed to discover the functional roles of lncRNA GAS5-AS1. The GAS5-AS1 expression in CC tissues was markedly decreased when compared with that in the adjacent normal tissues. The downregulation of GAS5-AS1 was significantly correlated with the advanced FIGO stage, distant metastasis, lymphatic metastasis and poor prognosis in patients with CC. Functionally, GAS5-AS1 drastically reduced CC cell proliferation, migration and invasion in vitro, and remarkably suppressed CC tumorigenicity and metastasis in vivo. Mechanistically, it was found that GAS5-AS1 interacted with the tumor suppressor GAS5, and increased its stability by interacting with RNA demethylase ALKBH5 and decreasing GAS5 N6-methyladenosine (m⁶A) modification. Moreover, it was shown that m⁶A-mediated GAS5 RNA degradation relied on the m⁶A reader protein YTHDF2-dependent pathway. Our findings reveal an important mechanism of epigenetic alteration in CC carcinogenesis and metastasis.

lncRNA NR_038323 Suppresses Renal Fibrosis in Diabetic Nephropathy by Targeting the miR-324-3p/DUSP1 Axis

Several studies have suggested that long intergenic noncoding RNAs are involved in the progression of diabetic nephropathy (DN). However, the exact role and regulatory mechanism of long noncoding RNA (lncRNA) NR_038323 in diabetic nephropathy (DN) remain largely unclear. In the present study, we found that lncRNA NR_038323 overexpression ameliorated the high glucose (HG)-induced expression levels of collagen I, collagen IV, and fibronectin, whereas lncRNA NR_038323 knockdown exerted the opposite effects. Moreover, the results of bioinformatic prediction, luciferase assay, and fluorescence in situ hybridization (FISH) demonstrated that lncRNA NR_038323 directly interacted with miR-324-3p. Additionally, miR-324-3p mimic aggravated the HG-induced expression levels of collagen I, collagen IV, and fibronectin by dual-specificity protein phosphatase-1 (DUSP1) expression to activate p38 mitogen-activated protein kinase (MAPK) and ERK1/2 pathways. In contrast, overexpression of DUSP1 attenuated the HG-induced expression levels of collagen I, collagen IV, and fibronectin via inactivation of p38 MAPK and ERK1/2 pathways. In addition, lncRNA NR_038323 knockdown increased the expression levels of collagen I, collagen IV, and fibronectin by upregulating DUSP1 expression during HG treatment, which were markedly reversed by miR-324-3p inhibitor. Furthermore, these molecular changes were verified in the human kidney samples of DN patients. Finally, overexpression of lncRNA NR_038323 ameliorated the interstitial fibrosis in STZ-induced diabetic nephrology (DN) rat via miR-324-3p/DUSP1/p38MAPK and ERK1/2 axis. In conclusion, our data indicate that overexpression of lncRNA NR_038323 may suppress HG-induced renal fibrosis via the miR-324-3p/DUSP1/p38MAPK and ERK1/2 axis, which provides new insights into the pathogenesis of DN.

Ubiquitination and Long Non-coding RNAs Regulate Actin Cytoskeleton Regulators in Cancer Progression

Actin filaments are a major component of the cytoskeleton in eukaryotic cells and play an important role in cancer metastasis. Dynamics and reorganization of actin filaments are regulated by numerous regulators, including Rho GTPases, PAKs (p21-activated kinases), ROCKs (Rho-associated coiled-coil containing kinases), LIMKs (LIM domain kinases), and SSH1 (slingshot family protein phosphate 1). Ubiquitination, as a ubiquitous post-transcriptional modification, deceases protein levels of actin cytoskeleton regulatory factors and thereby modulates the actin cytoskeleton. There is increasing evidence showing cytoskeleton regulation by long noncoding RNAs (lncRNAs) in cancer metastasis. However, which E3 ligases are activated for the ubiquitination of actin-cytoskeleton regulators involved in tumor metastasis remains to be fully elucidated. Moreover, it is not clear how lncRNAs influence the expression of actin cytoskeleton regulators. Here, we summarize physiological and pathological mechanisms of lncRNAs and ubiquitination control mediators of actin cytoskeleton regulators which that are involved in tumorigenesis and tumor progression. Finally, we briefly discuss crosstalk between ubiquitination and lncRNA control mediators of actin-cytoskeleton regulators in cancer.

LncRNA SNHG16 promotes tumor growth of pancreatic cancer by targeting miR-218-5p

Small Nucleolar RNA Host Gene (SNHG16) is a novel cancer-related long noncoding RNA (lncRNA) and functions as an oncogene in a variety of cancers. Nonetheless, the expression patterns, biological function, and potential mechanisms in SNHG16 in pancreatic cancer (PC) remain rarely known. An increase in expression of SNHG16 in PC samples against adjacent normal tissues was shown here. Increased SNHG16 was linked intimately to the tumor-node-metastasis (TNM) stage, distant metastasis, tumor differentiation, and poor overall survival. Loss-of-function experiments revealed that SNHG16 knockdown suppressed the proliferation, formation of colonies, ability to migrate and invade in vitro, along with a lowered growth of the tumor in a mouse model. Mechanistically, SNHG16 might serve as a sponge competitive endogenous RNA (ceRNA) for miR-218-5p, thereby playing a role in regulating the expression of high mobility group box 1 (HMGB1) expression, a known direct miR-218-5p target in PC cells. These results provide novel insight into PC tumorigenesis and suggest that SNHG16 could serve as a likely therapeutic intervention in PC.

Down-regulation of lncRNA GAS5 attenuates neuronal cell injury through regulating miR-9/FOXO3 axis in cerebral ischemic stroke

Cerebral ischemic stroke is a leading cause of neurological disability worldwide. Previous study reported that long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) was highly expressed in ischemic stroke. However, the mechanism underlying GAS5 in an inflammatory injury during an ischemic stroke remains poorly understood. An in vivo mouse model of middle cerebral artery occlusion (MCAO) and an in vitro cell model of oxygen-glucose deprivation (OGD) were established to induce cerebral ischemic stroke condition. The expressions of GAS5, microRNA-9 (miR-9) and forkhead box O3 (FOXO3) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot analysis, respectively. The neurological injury in vivo was investigated by neurological score and TTC staining. Cell apoptosis and inflammatory injury were analyzed by western blot, flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. The interaction between miR-9 and GAS5 or FOXO3 was explored by luciferase activity, RNA pull-down and RNA immunoprecipitation (RIP) assays. GAS5 expression was enhanced in the cerebral ischemic stroke model. Knockdown of GAS5 attenuated the cerebral infarct, neurological injury, apoptosis and inflammatory injury in the mouse MCAO model. miR-9 was bound to GAS5 and its overexpression inhibited cell apoptosis and inflammatory response in OGD-treated bEnd.3 cells, which was attenuated by GAS5. FOXO3 was a target of miR-9 and its restoration reversed the miR-9-mediated suppression of apoptosis and inflammation. Moreover, GAS5 promoted FOXO3 expression by competitively sponging miR-9. GAS5 knockdown alleviated neuronal cell injury by regulating miR-9/FOXO3, providing a new theoretical foundation for cerebral ischemic stroke.

Cerebral ischemic stroke is a leading cause of neurological disability worldwide.

Overexpression of lncRNA GAS5 suppresses prostatic epithelial cell proliferation by regulating COX-2 in chronic non-bacterial prostatitis

Chronic non-bacterial prostatitis (CNP) is a common urologic disease that is linked to the development of prostate cancer. Long non-coding RNA (lncRNA) GAS5 has been identified to mediate cell proliferation in prostate cancer, although its role in CNP is still unclear. Human prostate epithelial cell line RWPE-1 was induced by lipopolysaccharide (LPS) to mimic CNP model in vitro. Real-time PCR was performed to determine the expression of GAS5 and COX-2, while western blotting was used to evaluate the protein expression of COX-2. The interaction between GAS5 and COX-2 was determined using RNA pull-down and RNA immunoprecipitation (RIP). Cell proliferation was determined using MTT assay. The expression of GAS5 was decreased, while COX-2 was increased in prostatitis tissues and in LPS-induced RWPE-1 cells. The overexpression of GAS5 suppressed the protein level of COX-2, and inhibited cell proliferation of LPS-induced RWPE-1 cells and HPECs, which was rescued by the co-transfection with pcDNA-GAS5 and pcDNA-COX-2. GAS5 was confirmed to promote the ubiquitination of COX-2, and the in vivo GAS5-overexpressed CNP rat model decreased the motor scores, the volume of prostate tissues, the average number of inflammatory cells, prostatic proliferation, and COX-2 expression. Our findings revealed that overexpression of GAS5 inhibited cell proliferation via negatively regulating the expression of COX-2, thus alleviating the progression of CNP.

Long Noncoding RNA and Epithelial Mesenchymal Transition in Cancer

Epithelial-mesenchymal transition (EMT) is a multistep process that allows epithelial cells to acquire mesenchymal properties. Fundamental in the early stages of embryonic development, this process is aberrantly activated in aggressive cancerous cells to gain motility and invasion capacity, thus promoting metastatic phenotypes. For this reason, EMT is a central topic in cancer research and its regulation by a plethora of mechanisms has been reported. Recently, genomic sequencing and functional genomic studies deepened our knowledge on the fundamental regulatory role of noncoding DNA. A large part of the genome is transcribed in an impressive number of noncoding RNAs. Among these, long noncoding RNAs (lncRNAs) have been reported to control several biological processes affecting gene expression at multiple levels from transcription to protein localization and stability. Up to now, more than 8000 lncRNAs were discovered as selectively expressed in cancer cells. Their elevated number and high expression specificity candidate these molecules as a valuable source of biomarkers and potential therapeutic targets. Rising evidence currently highlights a relevant function of lncRNAs on EMT regulation defining a new layer of involvement of these molecules in cancer biology. In this review we aim to summarize the findings on the role of lncRNAs on EMT regulation and to discuss their prospective potential value as biomarkers and therapeutic targets in cancer.

lncRNA B4GALT1-AS1 promotes colon cancer cell stemness and migration by recruiting YAP to the nucleus and enhancing YAP transcriptional activity

Here, an RNA-sequencing assay revealed long noncoding RNAs (lncRNAs) with an ectopic expression between colon cancer (CC) and normal colon epithelial cells, in which lncRNA B4GALT1-AS1 exhibited the highest change. A 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay indicated that B4GALT1-AS1 knockdown had no effect on CC cell viability, however, cell clone formation analysis showed that B4GALT1-AS1 knockdown attenuated the capacity of cell clone formation. Additionally, gene set enrichment analysis of this data set revealed that positive enrichment of stem cell-differentiated signatures and negative embryonic stem cell function and adult tissue stem module were observed in CC cells with B4GALT1-AS1 knockdown. Furthermore, B4GALT1-AS1 knockdown suppressed the stemness-marker expression, the ability of cell spheroid formation, and ALDH1 activity in CC cells. Mechanistically, RNA-sequencing data found that the Hippo pathway in cancer was shown on pathways mostly upregulated by B4GALT1-AS1 knockdown, and B4GALT1-AS1 directly bound to the yes-associated protein (YAP), a downstream executor of the Hippo pathway, and B4GALT1-AS1 knockdown promoted the nuclear cytoplasm translocation of YAP and decreased YAP transcriptional activity. Notably, YAP overexpression attenuated the inhibitory effects mediated by B4GALT1-AS1 knockdown. Our results identify the direct binding of lncRNA B4GALT1-AS1 to YAP, which is responsible for CC cell stemness.

Growth arrest specific transcript 5 in tumorigenesis process: An update on the expression pattern and genomic variants

Growth arrest-specific 5 (GAS5) is a long non-coding RNA (lncRNA) with diverse functions in regulation of gene expression. Most studies have reported a role for this lncRNA in induction of cell apoptosis and suppression of tumorigenesis process. Although few studies demonstrated up-regulation of this lncRNA in tumor tissues compared to non-tumor tissues of the same origin, the results of in vitro functional studies mostly support the tumor suppressor role for GAS5. A number of recent studies have also shown associations between genomic variants of this gene and risk of cancer in some populations. The role of this lncRNA in modulation of response to anti-cancer regimens has been verified through both in vitro and clinical studies. Taken together, this lncRNA is a putative biomarker and therapeutic target in human malignancies.

Long noncoding RNA CASC11 promotes osteosarcoma metastasis by suppressing degradation of snail mRNA

Osteosarcoma (OS) is the most common primary bone tumor in adolescents. Dysregulation of long noncoding RNAs (lncRNAs) is associated with the cancer progression, of which cancer susceptibility candidate 11 (CASC11) has been indicated as an oncogene in several human cancers. However, the underlying mechanisms by which CASC11 contributes to OS metastasis remain undetermined. Here, we found that CASC11 expression in OS tissues was markedly higher than that in noncancerous tissues. Clinical association analysis revealed that high CASC11 expression correlated with clinical stage, distant metastasis and poor prognosis of OS patients. Gain- and loss-of-function assays demonstrated that CASC11 promoted migration, invasion, epithelial-mesenchymal transition (EMT) and metastasis of OS cells in vitro and in vivo. CASC11 associated with the EMT inducer Snail mRNA and increased its stability. Association of CASC11 with Snail mRNA blocked the repressing effect of miR-122, miR-145, miR-211, miR-34a and miR-137 on Snail. Moreover, CASC11-specific siRNAs significantly inhibit tumor metastasis in vivo. Taken together, our findings suggest that CASC11 may be a candidate prognostic biomarker and a novel therapeutic target for OS.

Altered expression of long non-coding RNA GAS5 in digestive tumors

Cancer has become one of the most important diseases that affect human health and life. The effects of cancer in the digestive system are particularly prominent. Recently, long non-coding RNA (lncRNA) has attracted the attention of more and more researchers and has become an emerging field of gene research. The lncRNA growth arrest-specific 5 (GAS5) is a novel lncRNA that has attracted the attention of researchers in recent years and plays an important role in the development of tumors, especially in digestive system tumors. GAS5 was first identified in a mouse cDNA library. It was generally considered that it has the role of tumor suppressor genes, but there are still studies that have a certain ability to promote cancer. Furthermore, the 5-bp indel polymorphism (rs145204276) in the GAS5 promoter region also has a carcinogenic effect. The discovery of GAS5 and in-depth study of single nucleotide polymorphism (SNP) mechanism can provide a new way for the prevention and treatment of digestive system tumors.

Long noncoding RNA DLX6-AS1 targets miR-124-3p/CDK4 to accelerate Ewing's sarcoma

Ewing's sarcoma is one of leading cause of malignancy occurred in the children and adolescents worldwide. Given the emerging critical role of long noncoding RNA (lncRNA) in the human cancer, as well as Ewing's sarcoma, we aim to identify the biological role of DLX6-AS1 in the tumorigenesis. Results unveil that DLX6-AS1 expression was increased in the tissue sample and cells. Functionally, the silencing of DLX6-AS1 could repress the proliferation and accelerate the apoptosis of Ewing's sarcoma cells. Mechanically, DLX6-AS1 functioned as the sponge of miR-124-3p, and then miR-124-3p targeted the 3'-UTR of CDK4 mRNA, forming the DLX6-AS1/miR-124-3p/CDK4 regulatory pathway. In conclusion, the critical role of DLX6-AS1 might unveil a potential therapeutic target for Ewing's sarcoma.