STAT3-induced upregulation of lncRNA DUXAP8 functions as ceRNA for miR-577 to promote the migration and invasion in colorectal cancer through the regulation of RAB14

The diagnostic and prognostic value of pseudogene SIGLEC17P in lung adenocarcinoma and a preliminary functional study

Among malignant tumors, lung adenocarcinoma (LUAD) is the leading cause of death worldwide. This study explored the diagnostic, prognostic value, and preliminary functional verification of sialic acid binding Ig like lectin 17, pseudogene (SIGLEC17P) in LUAD. Prognostic lncRNAs for LUAD were identified by The Cancer Genome Atlas and quantitative real-time PCR (qRT-PCR) was used to detect the expression of SIGLEC17P in LUAD and paracarcinoma tissues. Subsequently, lentiviral vectors were used to overexpress SIGLEC17P in A549 and H1299 cells. The effects of SIGLEC17P overexpression on the proliferation, migration, and invasiveness of LUAD cells (A549 and H1299) were evaluated by Cell Counting Kit-8, wound healing, and transwell migration assays, respectively. Bioinformatics analyses were performed to reveal the potential pathways in which SIGLEC17P is involved in LUAD. qRT-PCR results revealed low SIGLEC17P expression in LUAD tissues and a significant association with the N stage, T stage, and tumor node metastasis stage. Furthermore, the receiver operating characteristic curve demonstrated a reliable diagnostic value. The proliferation, migration, and invasion of LUAD cells were inhibited by overexpression of SIGLEC17P. Bioinformatics analyses suggested that SIGLEC17P might exert antioncogenic effects in LUAD through the mir-20-3p/ADH1B or mir-4476-5p/DPYSL axis. In summary, our results revealed that SIGLEC17P acts as a prognostic biomarker, independent prognostic factor, and potential therapeutic target for patients with LUAD.

LncRNA DUXAP8 induces breast cancer radioresistance by modulating the PI3K/AKT/mTOR pathway and the EZH2-E-cadherin/RHOB pathway

Radiation resistance poses a major clinical challenge in breast cancer (BC) treatment, but little is known about how long noncoding RNA (lncRNA) may regulate this phenomenon. Here, we reported that DUXAP8 was highly expressed in radioresistant BC tissues, and high expression of DUXAP8 was associated with poor prognosis. We found that the overexpression of DUXAP8 promoted radioresistance, while the knockdown of DUXAP8 expression increased radiosensitivity. Further studies revealed that DUXAP8 enhanced the radioresistance of BC cells by activating the PI3K/AKT/mTOR pathway and by repressing the expression of E-cadherin and RHOB through interaction with EZH2. Together, our work demonstrates that the overexpression of DUXAP8 promotes the resistance of BC cells toward radiation through modulating PI3K/AKT/mTOR pathway and EZH2-E-cadherin/RHOB axis. Targeting DUXAP8 may serve as a potential strategy to overcome radioresistance in BC treatment.

Pseudogenes and the associated ceRNA network as potential prognostic biomarkers for colorectal cancer

Colorectal cancer (CRC) is one of the most common and malignant carcinomas. Many long noncoding RNAs (lncRNAs) have been reported to play important roles in the tumorigenesis of CRC by influencing the expression of some mRNAs via competing endogenous RNA (ceRNA) networks and interacting with miRNAs. Pseudogene is one kind of lncRNA and can act as RNA sponges for miRNAs and regulate gene expression via ceRNA networks. However, there are few studies about pseudogenes in CRC. In this study, 31 differentially expressed (DE) pseudogenes, 17 DE miRNAs and 152 DE mRNAs were identified by analyzing the expression profiles of colon adenocarcinoma obtained from The Cancer Genome Atlas. A ceRNA network was constructed based on these RNAs. Kaplan-Meier analysis showed that 7 pseudogenes, 4 miRNAs and 30 mRNAs were significantly associated with overall survival. Then multivariate Cox regression analysis of the ceRNA-related DE pseudogenes was performed and a 5-pseudogene signature with the greatest prognostic value for CRC was identified. Moreover, the results were validated by the Gene Expression Omnibus database, and quantitative real-time PCR in 113 pairs of CRC tissues and colon cancer cell lines. This study provides a pseudogene-associated ceRNA network, 7 prognostic pseudogene biomarkers, and a 5-pseudogene prognostic risk signature that may be useful for predicting the survival of CRC patients.

LncRNA DUXAP8 as a prognostic biomarker for various cancers: A meta-analysis and bioinformatics analysis

Background: Dual homeoboxes A pseudogene 8 (DUXAP8) is a newly discovered long noncoding RNA that has been shown to function as an oncogene in a variety of human malignant cancers. By integrating available data, this meta-analysis sought to determine the relationship between clinical prognosis and DUXAP8 expression levels in diverse malignancies.

Materials and methods: A systematic search was performed to identify eligible studies from several electronic databases from their inception to 25 October 2021. Pooled odds ratios and hazard ratios with 95% CI were used to estimate the association between DUXAP8 expression and survival. For survival analysis, the Kaplan-Meier method and COX analysis were used. Furthermore, we utilized Spearman’s correlation analysis to explore the correlation between DUXAP8 and tumor mutational burden (TMB), microsatellite instability (MSI), the related genes of mismatch repair (MMR), DNA methyltransferases (DNMTs), and immune checkpoint biomarkers.

Results: Our findings indicated that overexpression of DUXAP8 was related to poor overall survival (OS) (HR = 1.63, 95% CI, 1.49–1.77, p < 0.001). In addition, elevated DUXAP8 expression was closely related to poor OS in several cancers in the TCGA database. Moreover, DUXAP8 expression has been associated with TMB, MSI, and MMR in a variety of malignancies.

Conclusion: This study revealed that DUXAP8 might serve as a prognostic biomarker and potential therapeutic target for cancer. It can be used to improve cancer diagnosis, discover potential treatment targets, and improve prognosis.

LncRNA MSTO2P promotes colorectal cancer progression through epigenetically silencing CDKN1A mediated by EZH2

BACKGROUND

Pseudogene-derived long non-coding RNAs (lncRNAs) have been reported to act as key regulatory factors of cancers. However, the study focused on pseudogene misato family member 2 (MSTO2P) in the occurrence and development of colorectal cancer (CRC) remains unclear.

METHODS

CCK-8, colony formation, and transwell assays clarified HT-29 and SW480 cell proliferation and invasion. Furthermore, flow cytometry was carried out to detect cell cycle and cell apoptosis. Subcellular localization assay indicated the location of MSTO2P in HT-29 cells. RIP and CHIP assays clarified the relationship of MSTO2P with target protein and gene in HT-29 cells.

RESULTS

MSTO2P expression was upregulated in CRC tissues and cells. Functional experiments revealed that inhibition of MSTO2P suppressed HT-29 and SW480 cell proliferation and invasion, and promoted cell cycle arrest and cell apoptosis. Besides, MSTO2P epigenetically down-regulated cyclin-dependent kinase inhibitor 1A (CDKN1A) via binding to the enhancer of zeste homolog 2 (EZH2) in the nucleus. At last, rescue experiments proved the anti-tumor effect of inhibition of MSTO2P was partially recovered due to the knockdown of CDKN1A in HT-29 cells.

CONCLUSION

LncRNA MSTO2P promoted colorectal cancer progression through epigenetically silencing CDKN1A mediated by EZH2.

Functions of lncRNA DUXAP8 in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) poses a serious threat to public health due to its significant morbidity and mortality rates. The processes of NSCLC formation and development are quite complex and involve numerous regulatory biomolecules. Long non-coding RNAs (lncRNAs) have attracted attention since they have been found to play critical roles in the tumorigenesis of various human malignancies. Recently, double homeobox A pseudogene 8 (DUXAP8) was identified as an oncogenic lncRNA that is overexpressed in different tumor types. In NSCLC, high expression of DUXAP8 is associated with poor prognosis in patients. The regulatory mechanism underlying the oncogenic effects of DUXAP8 can be divided into transcriptional level and post-transcriptional level. DUXAP8 promotes proliferation, epithelial-mesenchymal transition, and aerobic glycolysis in NSCLC cells. Moreover, DUXAP8 shows potential for the diagnosis and treatment of NSCLC. Herein, we review the molecular mechanisms underlying the DUXAP8-mediated phenotypes of NSCLC as well as its potential clinical applications.

LncRNA <i>SNHG16</i> promotes colorectal cancer proliferation by regulating ABCB1 expression through sponging miR-214-3p

Mounting evidence indicates that long non-coding RNAs (lncRNAs) have critical roles in colorectal cancer (CRC) progression, providing many potential diagnostic biomarkers, prognostic biomarkers, and treatment targets. Here, we sought to investigate the role and underlying regulatory mechanism of lncRNA small nucleolar RNA host gene 16 (SNHG16) in CRC. The expressions of SNHG16 in CRC were identified by RNA-sequencing and quantitative reverse transcription PCR. The functions of SNHG16 were explored by a series of in vitro and in vivo assays (colony formation assay, flow cytometry assay, and xenograft model). Bioinformatics analysis, RNA fluorescencein situ hybridization and luciferase reporter assay were used to investigate the regulatory mechanism of effects of SNHG16. SNHG16 was found to be significantly elevated in human CRC tissues and cell lines. Functional studies suggested that SNHG16 promoted CRC cell growth both in vitro and in vivo. Mechanistically, we identified that SNHG16 is expressed predominantly in the cytoplasm. SNHG16 could interact with miR-214-3p and up-regulated its target ABCB1. This study indicated that SNHG16 plays an oncogenic role in CRC, suggesting it could be a novel biomarker and therapeutic target in CRC.

FGD5‑AS1 is an oncogenic lncRNA in pancreatic cancer and regulates the Wnt/β‑catenin signaling pathway via miR‑577

The objective of the present study was to clarify the expression characteristics of long non-coding RNA (lncRNA) FGD5 antisense RNA 1 (FGD5-AS1) in pancreatic cancer, as well as its biological function and underlying mechanism. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was utilized for the detection of FGD5-AS1 and microRNA (miR)-577 expression levels in pancreatic cancer tissues. Transfection was performed to upregulate or downregulate FGD5-AS1 in pancreatic cancer cell lines. MTT and Transwell assays were then utilized to detect the proliferation, migration and invasion of cancer cells, respectively. Subsequently, dual-luciferase reporter gene assay, RNA immunoprecipitation assay, RNA pull-down assay, RT-qPCR, western blotting, and Pearson's correlation analysis were employed to confirm the regulatory relationships among FGD5-AS1, miR-577, low-density lipoprotein receptor-related protein 6 (LRP6) and β-catenin. Western blotting was employed to determine the expression levels of Axin2, cyclin D1 and c-Myc. The expression level of FGD5-AS1 was upregulated in pancreatic cancer tissues and cell lines. FGD5-AS1 knockdown inhibited pancreatic cancer cell proliferation, migration and invasion. By contrast, miR-577 was significantly inhibited in pancreatic cancer cells and tissues; its downregulation promoted pancreatic cancer cell proliferation, migration and invasion, and reversed the effects of FGD5-AS1 knockdown on pancreatic cancer cells. In addition, it was revealed that miR-577 was a target of FGD5-AS1, and FGD5-AS1 could modulate the expression levels of LRP6, β-catenin, Axin2, cyclin D1 and c-Myc via suppressing miR-577. In conclusion, in pancreatic cancer, highly expressed FGD5-AS1 activated the Wnt/β-catenin signaling and promoted cancer cell proliferation, migration and invasion via suppression of miR-577.

Long non-coding RNA DUXAP8 elevates RCN2 expression and facilitates cell malignant behaviors and angiogenesis in cervical cancer via sponging miR-1297

BACKGROUND

Cervical cancer (CC) endangers women's health in the world range. Accumulating studies have revealed the crucial regulatory role of long non-coding RNAs (lncRNAs) in multiple malignancies, including CC. Our study aimed to explore the role of lncRNA double homeobox A pseudogene 8 (DUXAP8) in cervical carcinogenesis.

METHODS

Gene expressions in CC were assessed by RT-qPCR. Function experiments and tube formation assays were performed to evaluate the role of DUXAP8 in CC cells. Subcellular fractionation and FISH assays were conducted to determine the subcellular location of DUXAP8. Luciferase reporter, RNA pull down and RIP assays were conducted to investigate the mechanism of DUXAP8.

RESULTS

DUXAP8 was notably upregulated in CC cells. Downregulation of DUXAP8 repressed cell malignant behaviors and angiogenesis in CC. Mechanically, DUXAP8 boosted the expression of reticulocalbin-2 (RCN2) through relieving the binding of miR-1297 to RCN2 3'-UTR. Moreover, miR-1297 inhibition and RCN2 overexpression could counteract the inhibitory effects of DUXAP8 knockdown on the malignant phenotypes of CC cells. Besides, enhanced RCN2 expression restored the tumor growth in vivo that was inhibited by DUXAP8 repression.

CONCLUSIONS

DUXAP8 promotes malignant behaviors in CC cells via regulating miR-1297/RCN2 axis.

Development and validation of ferroptosis-related lncRNAs prognosis signatures in kidney renal clear cell carcinoma

Background

Ferroptosis is a recently recognised new type of cell death which may be a potential target for cancer therapy. In the present study, we aimed to screen ferroptosis-related differentially expressed long non-coding RNAs as biomarkers to predict the outcome of kidney renal clear cell carcinoma.

Methods

RNAseq count data and corresponding clinical information were obtained from the Cancer Genome Atlas database. Lists of ferroptosis-related genes and long non-coding RNAs were obtained from the FerrDb and GENCODE databases, respectively. The candidate prognostic signatures were screened by Cox regression analyses and least absolute shrinkage and selection operator analyses.

Results

Three ferroptosis-related long non-coding RNAs (DUXAP8, LINC02609, and LUCAT1) were significantly correlated with the overall survival of kidney renal clear cell carcinoma independently. Kidney renal clear cell carcinoma patients with high-risk values displayed worse OS. Meanwhile, the expression of these three ferroptosis-related long non-coding RNAs and their risk scores were significantly correlated with clinicopathological features. Principal component analyses showed that patients with kidney renal clear cell carcinoma have differential risk values were well distinguished by the three ferroptosis-related long non-coding RNAs.

Conclusions

The present study suggests that the risk assessment model constructed by these three ferroptosis-related long non-coding RNAs could accurately predict the outcome of kidney renal clear cell carcinoma. We also provide a novel perspective for cancer prognosis screening.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02284-1.

Long Non-coding RNA Double Homeobox A Pseudogene 8: A Novel Oncogenic Propellant in Human Cancer

A growing number of studies are reporting important roles played by long non-coding RNAs (lncRNAs) in various pathological and physiological processes. LncRNAs are implicated in numerous genomic regulatory functions at different levels, including regulation of transcription, post-transcriptional processes, genomic stability, and epigenetic genome modifications. Double homeobox A pseudogene 8 (DUXAP8), a novel lncRNA, has been reported to be involved in many cancers, including gastric, colorectal, esophageal, bladder, oral, ovarian, lung, and pancreatic cancers as well as hepatocellular carcinoma (HCC). DUXAP8 plays specific oncogenic roles via numerous malignancies promoting pathways. DUXAP8 is frequently dysregulated in multiple cancers, acting as a sponge to downregulate various tumor-suppressing microRNA activities. In this review, we comprehensively explore DUXAP8 expression and prognosis across cancer types, and systematically summarize current evidence concerning the functions and molecular mechanisms of DUXAP8 in tumorigenesis and progression. We conclude that DUXAP8 is a potential biomarker and therapeutic target for multiple cancers.

A Positive Feedback Loop of lncRNA MIR31HG-miR-361-3p -YY1 Accelerates Colorectal Cancer Progression Through Modulating Proliferation, Angiogenesis, and Glycolysis

Background

Colorectal cancer (CRC) is a common malignant tumor with high metastatic and recurrent rates. This study probes the effect and mechanism of long non-coding RNA MIR31HG on the progression of CRC cells.

Materials and Methods

Quantitative real-time PCR (qRT-PCR) was used to analyze the expression of MIR31HG and miR-361-3p in CRC tissues and normal tissues. Gain- or loss-of-function assays were conducted to examine the roles of MIR31HG, miR-361-3p and YY1 transcription factor (YY1) in the CRC progression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and colony formation experiment were conducted to test CRC cell proliferation. CRC cell invasion was determined by Transwell assay. The glucose detection kit and lactic acid detection kit were utilized to monitor the levels of glucose and lactate in CRC cells. The glycolysis level in CRC cells was examined by the glycolytic stress experiment. Western blot was performed to compare the expression of glycolysis-related proteins (PKM2, GLUT1 and HK2) and angiogenesis-related proteins (including VEGFA, ANGPT1, HIF1A and TIMP1) in HUVECs. The binding relationships between MIR31HG and miR-361-3p, miR-361-3p and YY1 were evaluated by the dual-luciferase reporter assay and RNA immunoprecipitation (RIP).

Results

MIR31HG was up-regulated in CRC tissues and was associated with poorer prognosis of CRC patients. The in-vitro and in-vivo experiments confirmed that overexpressing MIR31HG heightened the proliferation, growth, invasion, glycolysis and lung metastasis of CRC cells as well as the angiogenesis of HUVECs. In addition, MIR3HG overexpression promoted YY1 mRNA and protein level, and forced overexpression of YY1 enhanced MIR31HG level. Overexpressing YY1 reversed the tumor-suppressive effect mediated by MIR31HG knockdown. miR-361-3p, which was inhibited by MIR31HG overexpression, repressed the malignant behaviors of CRC cells. miR-361-3p-mediated anti-tumor effects were mostly reversed by upregulating MIR31HG. Further mechanism studies illustrated that miR-361-3p targeted and negatively regulated the expression of YY1.

Conclusion

This study reveals that MIR31HG functions as an oncogenic gene in CRC via forming a positive feedback loop of MIR31HG-miR-361-3p-YY1.

YY1-inudced activation of lncRNA DUXAP8 promotes proliferation and suppresses apoptosis of triple negative breast cancer cells through upregulating SAPCD2

Double homeobox A pseudogene 8 (DUXAP8) belongs to long non-coding RNAs (lncRNAs), which has been proven to promote the biological processes of multiple human cancers. Triple-negative breast cancer (TNBC) is the leading cause of cancer-related death in women worldwide. However, the specific role of lncRNA DUXAP8 and its underlying mechanism in TNBC remains to be unclear. We detected the expression of DUXAP8 in TNBC cells through qRT-PCR analysis. The effects of DUXAP8 silencing on TNBC cell proliferation and apoptosis were identified using CCK-8 assay, EdU assay, flow cytometry analysis and TUNEL assay. The downstream microRNA (miRNA) and messenger RNA (mRNA) of DUXAP8 were searched out through bioinformatics analysis and mechanism experiments. Rescue assays were conducted to verify the involvement of suppressor APC domain containing 2 (SAPCD2) in DUXAP8-mediated TNBC cell proliferation and apoptosis. DUXAP8 was highly expressed in TNBC cells compared to that in normal breast cells. Knockdown of DUXAP8 inhibited TNBC cell proliferation and accelerated cell apoptosis. DUXAP8 interacted with miR-29a-3p and thus enhanced the expression of SAPCD2. Moreover, YY1 transcription factor could bind to DUXAP8 promoter to activate the transcription of DUXAP8. YY1-induced transcriptional activation of DUXAP8 promotes TNBC cell growth through miR-29a-3p/SAPCD2 axis.

Identification of long non-coding RNA signatures for squamous cell carcinomas and adenocarcinomas

Studies have demonstrated that both squamous cell carcinomas (SCCs) and adenocarcinomas (ACs) possess some common molecular characteristics. Evidence has accumulated to support the theory that long non-coding RNAs (lncRNAs) serve as novel biomarkers and therapeutic targets in complex diseases such as cancer.

In this study, we aimed to identify pan lncRNA signatures that are common to squamous cell carcinomas or adenocarcinomas with different tissues of origin. With the aid of elastic-net regularized regression models, a 35-lncRNA pan discriminative signature and an 11-lncRNA pan prognostic signature were identified for squamous cell carcinomas, whereas a 6-lncRNA pan discriminative signature and a 5-lncRNA pan prognostic signature were identified for adenocarcinomas. Among them, many well-known cancer relevant genes such as MALAT1 and PVT1 were included.

The identified pan lncRNA lists can help experimental biologists generate research hypotheses and adopt existing treatments for less prevalent cancers. Therefore, these signatures warrant further investigation.

The Pseudogene DUXAP8 Promotes Colorectal Cancer Cell Proliferation, Invasion, and Migration by Inducing Epithelial-Mesenchymal Transition Through Interacting with EZH2 and H3K27me3

Background

Colorectal cancer (CRC) is the third leading cause of cancer death worldwide. The long noncoding RNA (lncRNA) DUXAP8 has been reported to play an important role in CRC. This study investigated the mechanism by which this lncRNA regulates CRC progression.

Methods

The levels of lncRNA DUXAP8 in CRC tissues and cell lines were detected by qRT-PCR. We then knocked down or forced overexpression of DUXAP8, and the resultant effect on cell proliferation was determined by the Edu assay and a cell cycle analysis, and the effect on cell apoptosis was determined by flow cytometry. The cell invasion/migration ability and the epithelial-to-mesenchymal transition (EMT) markers were determined by Transwell/wound healing assays and Western blotting. CHIP and RNA pull-down assays were performed to determine the binding of Zeste gene enhancer 2 (EZH2) and trimethylated histone H3 to Lys27 (H3K27me3) in the E-cadherin promoter regions, or to DUXAP8.

Results

The levels of lncRNA DUXAP8 were significantly increased in CRC tissues and CRC cell lines. Knockdown of lncRNA DUXAP8 inhibited cell proliferation and the EMT process, and increased cell apoptosis, and overexpression of lncRNA DUXAP8 had an opposite effect. Both ChIP and RNA pull-down assays showed that the E-cadherin promoter region was bound by H3K27me3 and EZH2, which restrained E-cadherin expression. However, that binding was suppressed and E-cadherin expression was markedly induced by lncRNA DUXAP8 knockdown. Furthermore, lncRNA DUXAP8 could interact with EZH2 and H3K27me3.

Conclusion

Our data indicated that lncRNA DUXAP8 could induce the progression of CRC by negatively regulating E-cadherin via interaction with EZH2 and H3K27me3. These findings suggest lncRNA DUXAP8 as target for treating CRC.

lncRNA DUXAP8 Facilitates Multiple Malignant Phenotypes and Resistance to PARP Inhibitor in HCC via Upregulating FOXM1

In this study, we examined the clinical significance and molecular mechanisms of a long non-coding RNA (lncRNA), double homeobox A pseudogene 8 (DUXAP8) in hepatocellular carcinoma (HCC). DUXAP8 expression was compared using quantitative real-time PCR in HCC versus adjacent tissues and in HCC cell lines versus normal hepatic epithelial cells. The correlations between DUXAP8 level and clinicopathological features were analyzed. Assays including MTT, colony-forming analysis, Transwell assay, western blot, xenograft formation, experimental metastasis, luciferase assay, RNA pull-down, and RNA immunoprecipitation were used to examine DUXAP8-induced malignant phenotypes, its regulation on forkhead box protein M1 (FOXM1), and the importance of FOXM1 in mediating DUXAP8 phenotypes. Our results showed that DUXAP8 was significantly upregulated in HCC tissues or cell lines associated with tumors of advanced grades, tumors that were positive for lymph node metastasis, and patients with poor overall survival. DUAXP8 was essential in maintaining multiple malignant phenotypes (including resistance to olaparib) both in vitro and in vivo. Mechanistically, DUXAP8 upregulated FOXM1 expression by sponging miR-485-5p and interacting with the RNA-binding protein Fused in Sarcoma (FUS). Functionally, FOXM1 essentially mediated the oncogenic phenotypes of DUXAP8. Collectively, DUXAP8 acts through two distinct mechanisms to upregulate FOXM1 and becomes a pleotropic oncogenic lncRNA in HCC.

The development and controversy of competitive endogenous RNA hypothesis in non-coding genes

As a momentous post-transcriptional regulator, microRNAs (miRNAs) are attracting more and more attention. The classical miRNAs regulated mechanism shows it binds to the targets' 3'UTR thus play the role in post-transcription. Meanwhile, single miRNA can target multiple genes, so those should compete to bind that miRNA. Vice versa, single gene can sponge mass of miRNAs as well. Thus the competitive endogenous RNAs (ceRNAs) hypothesis was put forward in 2011. The ceRNA hypothesis has made huge achievements, in particular in non-coding genes, which including long non-coding RNAs (lncRNAs), circle RNAs (circRNAs) and pseudogenes, even viral transcripts. It also contributed greatly to epigenetics development. However, an increasing number of controversies have occurred with applause. Based on this situation, this review introduces something in detail about the ceRNAs hypothesis achieved in lncRNAs, circRNAs, pseudogenes and viral transcripts, respectively. Meanwhile, it also covers controversy of the ceRNAs hypothesis.

Targeting STAT3 in Cancer Immunotherapy

As a point of convergence for numerous oncogenic signaling pathways, signal transducer and activator of transcription 3 (STAT3) is central in regulating the anti-tumor immune response. STAT3 is broadly hyperactivated both in cancer and non-cancerous cells within the tumor ecosystem and plays important roles in inhibiting the expression of crucial immune activation regulators and promoting the production of immunosuppressive factors. Therefore, targeting the STAT3 signaling pathway has emerged as a promising therapeutic strategy for numerous cancers. In this review, we outline the importance of STAT3 signaling pathway in tumorigenesis and its immune regulation, and highlight the current status for the development of STAT3-targeting therapeutic approaches. We also summarize and discuss recent advances in STAT3-based combination immunotherapy in detail. These endeavors provide new insights into the translational application of STAT3 in cancer and may contribute to the promotion of more effective treatments toward malignancies.

STAT3-Induced Upregulation of lncRNA CASC9 Promotes the Progression of Bladder Cancer by Interacting with EZH2 and Affecting the Expression of PTEN

Objective

Long non-coding RNA (lncRNA) cancer susceptibility candidate 9 (CASC9) has been reported to play a vital role in tumorigenesis. This study explored the biological role of CASC9 and its regulation mechanism in bladder cancer (BC).

Methods

Gene expression was evaluated using quantitative reverse transcription polymerase chain reaction and Western blot. The functional role of CASC9 in BC was studied using Cell Counting Kit-8, colony formation assay, scratch wound healing assay, transwell invasion assay, and xenograft tumor assay. In addition, the mechanism of CASC9 function in BC was determined using RNA immunoprecipitation assay and chromatin immunoprecipitation assay.

Results

CASC9 was upregulated in BC tissues and cell lines, and correlated with the staging and metastasis in BC. Knockdown of CASC9 inhibited the proliferation, migration, and invasion of BC cells. Similarly, silencing of CASC9 inhibited tumor growth in vivo. Signal transducer and activator of transcription 3 (STAT3) was upregulated in BC tissues and cell lines, and positively correlated with CASC9 in BC tissues. Moreover, CASC9 was shown to be regulated by STAT3 in BC cells. Furthermore, CASC9 regulated phosphatase and tensin homolog (PTEN) expression by interacting with enhancer of zeste homolog 2 (EZH2). More significantly, CASC9 silencing-mediated inhibition of BC progression was partly reversed by EZH2 overexpression or PTEN inhibition.

Conclusion

Upregulation of CASC9 induced by STAT3 promoted the progression of BC by interacting with EZH2 and affecting the expression of PTEN, representing a novel regulatory mechanism for BC progression.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.

Long Non-Coding RNA SNHG16 Activates USP22 Expression to Promote Colorectal Cancer Progression by Sponging miR-132-3p

Background

Colorectal cancer (CRC) is the most common cause of cancer-related mortality in the world. Long non-coding RNAs (lncRNAs) are involved in the development of many cancers. However, studies on the effect of lncRNA small nucleolar RNA host gene 16 (SNHG16) on the proliferation, metastasis and apoptosis of CRC are still few.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine the expression levels of SNHG16, microRNA-132-3p (miR-132-3p) and ubiquitin specific peptidase 22 (USP22). The proliferation, apoptosis, migration and invasion of CRC cells were evaluated by the 3-(4,5-dimethyl-2 thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, flow cytometry and transwell assay, respectively. Dual-luciferase reporter assay was used to verify the interactions among SNHG16, miR-132-3p and USP22. Also, Western blot analysis was used to assess the protein levels of USP22 and metastasis-related markers. Moreover, mice xenograft models were used to determine the effect of SNHG16 on CRC tumor growth in vivo.

Results

SNHG16 was highly expressed in CRC tissues and cells. Knockdown of SNHG16 reduced the proliferation, migration, invasion, and promoted the apoptosis of CRC cells. MiR-132-3p could interact with SNHG16, and its inhibitor recovered the suppression effect of silenced SNHG16 on CRC cell progression. Besides, USP22 was a target of miR-132-3p, and its overexpression restored the inhibition effect of miR-132-3p mimic on CRC cell progression. In addition, interference of SNHG16 reduced CRC tumor growth in vivo.

Conclusion

LncRNA SNHG16 might act as an oncogene in CRC. The discovery of the SNHG16/miR-132-3p/USP22 pathway provided new thinking for the treatment of CRC.

LncRNA SNHG3 sponges miR-577 to up-regulate SMURF1 expression in prostate cancer

Prostate cancer remains one of the most prevalent cancers and the main causes of cancer-related deaths in males. Various articles introduced that long noncoding RNAs (lncRNAs) are found in vital functions in the development and progression of cancers. Although SNHG3 (small nucleolar RNA host gene 3) has been investigated in many cancers, now researches on the role and mechanism of SNHG3 in prostate cancer are lacked. In this work, SNHG3 exerted high expression in prostate cancer cell lines. Suppression of SNHG3 inhibited cell proliferation, migration, EMT (epithelial-mesenchymal transition) process and promoted cell apoptosis. Additionally, it was found that SNHG3 could bind with miR-577. Subsequently, SMURF1 (Smad ubiquitination regulatory factor 1) was identified as a downstream target of miR-577 and had a negative correlation with miR-577. SNHG3 was found to positively regulate SMURF1 expression. Furthermore, rescue assays demonstrated that co-transfection of pcDNA3.1/SMURF1 reversed the effects of SNHG3 knockdown in cell proliferation, migration, EMT process and cell apoptosis. SNHG3 also promoted tumorigenesis in vivo. All the results above explained that SNHG3 accelerated prostate cancer progression by sponging miR-577 to up-regulate SMURF1 expression, suggesting that SNHG3 may act as a biomarker for prostate cancer patients.

Identification of prognostic long noncoding RNAs associated with spontaneous regression of neuroblastoma

Background

The association between long noncoding RNAs (lncRNAs) and spontaneous regression of neuroblastoma (NB) has rarely been investigated and remains unknown.

Objective

To identify prognostic lncRNAs involved in the spontaneous regression of NB.

Methods

Differential expression analyses were performed between those samples with an outcome of death in stage 4 NB group and those samples with an outcome of survival in stage 4S NB group in two independent public datasets, respectively. Univariate Cox proportional hazard regression survival analysis was performed in each of the entire cohort to identify those lncRNAs significantly associated with overall survival (OS). Those lncRNAs independently associated with OS were then identified by multivariate Cox survival analysis and used to construct an lncRNA risk score.

Results

A total of 20 differentially expressed and survival‐related lncRNAs were identified sharing between the two independent cohorts. The expression of each of these 20 lncRNAs was significantly correlated with the expression of NTRK1, which is a well‐known factor involved in NB spontaneous regression. Four lncRNAs (LNC00839, FIRRE, LOC283177, and LOC101928100) were identified to be significantly associated with survival independent with each other and a four‐lncRNA signature risk score was constructed. Patients with high lncRNA signature risk score had a significantly poorer OS and event‐free survival than those with low lncRNA signature risk score. The four‐lncRNA signature has a good performance in predicting survival independent with MYCN amplification (nonamplified vs amplified), age status (<18 months vs ≥18 months), risk status (low risk vs high risk), and International Neuroblastoma Staging System (INSS) stage (INSS 1/2/3/4S vs INSS 4).

Conclusions

We identified 20 survival‐related lncRNAs that might be associated with the spontaneous regression of NB and developed a four‐lncRNA signature risk score. The four‐lncRNA signature is an independent prognostic factor for survival of NB patients.

Pseudogene-Derived lncRNAs and Their miRNA Sponging Mechanism in Human Cancer

Pseudogenes, abundant in the human genome, are traditionally considered as non-functional “junk genes.” However, recent studies have revealed that pseudogenes act as key regulators at DNA, RNA or protein level in diverse human disorders (including cancer), among which pseudogene-derived long non-coding RNA (lncRNA) transcripts are extensively investigated and has been reported to be frequently dysregulated in various types of human cancer. Growing evidence demonstrates that pseudogene-derived lncRNAs play important roles in cancer initiation and progression by serving as competing endogenous RNAs (ceRNAs) through competitively binding to shared microRNAs (miRNAs), thus affecting both their cognate genes and unrelated genes. Herein, we retrospect those current findings about expression, functions and potential ceRNA mechanisms of pseudogene-derived lncRNAs in human cancer, which may provide us with some crucial clues in developing potential targets for cancer therapy in the future.

Long noncoding RNA DUXAP8 contributes to the progression of hepatocellular carcinoma via regulating miR-422a/PDK2 axis

Background

Hepatocellular carcinoma (HCC) is one of the most deadly cancer worldwide. Multiple long noncoding RNAs (lncRNAs) are recently identified as crucial oncogenic factors or tumor suppressors. In this study, we explored the functon and mechanism of lncRNA double homeobox A pseudogene 8 (DUXAP8) in the progression of HCC.

Methods

Expression levels of DUXAP8 in HCC tissue samples were measured using qRT‐PCR. The association between pathological indexes and the expression of DUXAP8 was also analyzed. Human HCC cell lines SMMC‐7721 and QSG‐7701 were used in in vitro studies. CCK‐8 assay was used to assess the effect of DUXAP8 on HCC cell line proliferation. Scratch healing assay and Transwell assay were conducted to detect the effect of DUXAP8 on migration and invasion. Furthermore, dual‐luciferase reporter assay was used to confirm targeting relationship between miR‐422a and DUXAP8. Additionally, Western blot was used to detect the regulatory function of DUXAP8 on pyruvate dehydrogenase kinase 2 (PDK2).

Results

DUXAP8 expression HCC clinical samples was significantly increased and this was correlated with unfavorable pathological indexes. High expression of DUXAP8 was associated with shorter overall survival time of patients. Its overexpression remarkably facilitated the proliferation, metastasis, and epithelial‐mesenchymal transition of HCC cells. Accordingly, knockdown of it suppressed the malignant phenotypes of HCC cells. Overexpression of DUXAP8 significantly reduced the expression of miR‐422a by sponging it, but enhanced the expression of PDK2.

Conclusions

DUXAP8 was a sponge of tumor suppressor miR‐422a in HCC, enhanced the expression of PDK2 indirectly, and functioned as an oncogenic lncRNA.