Prognostic values of long noncoding RNA PVT1 in various carcinomas: An updated systematic review and meta-analysis

Knockdown of lncRNA PVT1 protects human trabecular meshwork cells against H2O2-induced injury via the regulation of the miR-29a-3p/VEGF/MMP-2 axis

Purpose

Human trabecular meshwork cell (HTMC) dysfunction results in imbalanced aqueous humor inflow and outflow, leading to an increase in intraocular pressure (IOP). Uncontrolled high IOP can promote the occurrence of glaucoma, an irreversible optic neuropathy. Here, we explored whether the long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1)/microRNA-29a-3p (miR-29a-3p) axis could ameliorate HTMC dysfunction under oxidative stress by modulating the expression of the proangiogenic factor vascular endothelial growth factor (VEGFA) and the profibrotic factor metalloproteinase-2 (MMP-2).

Methods

HTMCs were cultured under H2O2-induced oxidative stress for 48 h. The expression of lncRNA PVT1, miR-29a-3p, VEGFA, MMP-2, intracellular adhesion molecule-1 (ICAM-1), and alpha-smooth muscle actin (α-SMA) was detected by reverse transcription quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. Interference experiments were conducted via the transfection of HTMCs with small interfering RNA (siRNA) targeting lncRNA PVT1 or miR-29a-3p mimics. A luciferase reporter assay was undertaken to identify the presence of a miR-29a-3p binding site in lncRNA PVT1. Flow cytometry and Transwell and Cell Counting Kit-8 assays were employed to evaluate HTMC functions under oxidative stress with different treatments.

Results

In HTMCs, the expression of lncRNA PVT1 was induced by H2O2 treatment, whereas that of miR-29a-3p was inhibited. The levels of angiogenic factors (VEGFA, ICAM-1) and fibrosis-associated mediators (MMP-2, α-SMA) were upregulated in HTMCs under oxidative stress. The siRNA-mediated suppression of lncRNA PVT1 or the upregulation of miR-29a-3p significantly suppressed the expression of VEGFA, MMP-2, ICAM-1, and α-SMA. A luciferase reporter assay confirmed that lncRNA PVT1 directly targeted miR-29a-3p and acted as a miR-29a-3p sponge. The knockdown of lncRNA PVT1 restored the level of miR-29a-3p in H2O2-treated HTMCs, thereby inhibiting VEGFA and MMP-2, its target mRNAs. HTMC dysfunction, including increased apoptosis and decreased cell mobility and viability, could be effectively ameliorated by lncRNA PVT1 downregulation or miR-29a-3p overexpression under oxidative stress.

Conclusion

LncRNA PVT1 has potential as a therapeutic target for inhibiting VEGFA and MMP-2, thus protecting HTMCs, suppressing the progression of fibrosis, and, consequently, improving the outcome of glaucoma filtration surgery.

Prognostic and clinicopathological values of LINC00665 in cancers: a systematic review and China population-based meta-analysis

BACKGROUND

Recent studies have uncovered that the aberrant expression of LINC00665 contributes to the malignant pathological process of various cancers and is closely related to the unfavorable prognosis of patients with cancer. However, a systematic analysis of the prognostic and clinicopathologic values of LINC00665 in cancers has not been conducted.

OBJECTIVE

We aim to clarify the association of LINC00665 expression with patient survival and clinicopathologic phenotypes in cancers.

METHODS

An electronic search of PubMed, Embase and Web of Science was performed to select eligible literature. Pooled hazard ratio (HR) and odds ratio (OR) were calculated to assess the clinical importance of LINC00665. The fixed-effects model was used to analyze the combined HR values and 95% CI when the studies had no significant heterogeneity (P > 0.1 for the Chi-square test or I2 < 50%). Begg's test and sensitivity analysis were also conducted. This study was registered in The International Prospective Register of Systematic Reviews (PROSPERO registration number: CRD42021290123).

RESULTS

A total of 710 patients from 10 eligible studies were enrolled in this meta-analysis, which was based on China population. The pooled results of this analysis revealed that high-level expression of LINC00665 was notably correlated with poor overall survival (HR = 2.08, 95% CI = 1.57-2.75) and recurrence-free survival (HR = 2.49, 95% CI = 1.63-3.80) in human cancers. Elevated LINC00665 expression was also correlated with more advanced clinical stage, earlier lymph node metastasis, lower tumor differentiation, earlier distant metastasis and larger tumor size.

CONCLUSION

LINC00665 expression was critically related to the cancer prognosis, which has important prognostic implications for clinical prediction.

Non-coding RNAs in enzalutamide resistance of castration-resistant prostate cancer

Enzalutamide (Enz) is a next-generation androgen receptor (AR) antagonist used to treat castration-resistant prostate cancer (CRPC). Unfortunately, the relapsing nature of CRPC results in the development of Enz resistance in many patients. Non-coding RNAs (ncRNAs) are RNA molecules that do not encode proteins, which include microRNAs (miRNA), long ncRNAs (lncRNAs), circular RNAs (circRNAs), and other ncRNAs with known and unknown functions. Recently, dysregulation of ncRNAs in CRPC, particularly their regulatory function in drug resistance, has attracted more and more attention. Herein, we introduce the roles of dysregulation of different ncRNAs subclasses in the development of CRPC progression and Enz resistance. Recently determined mechanisms of Enz resistance are discussed, focusing mainly on the role of AR-splice variant-7 (AR-V7), mutations, circRNAs and lncRNAs that act as miRNA sponges. Also, the contributions of epithelial-mesenchymal transition and glucose metabolism to Enz resistance are discussed. We summarize the different mechanisms of miRNAs, lncRNAs, and circRNAs in the progression of CRPC and Enz resistance, and highlight the prospect of future therapeutic strategies against Enz resistance.

LncRNA SNHG4 Modulates EMT Signal and Antitumor Effects in Endometrial Cancer through Transcription Factor SP-1

Long non-coding RNAs (lncRNAs) are implicated in the initiation and progression of a variety of tumors, including endometrial cancer. However, the mechanisms of lncRNA in endometrial cancer formation and progression remain largely unknown. In this study, we confirmed that the lncRNA SNHG4 is upregulated in endometrial cancer and correlates with lower survival rates in endometrial cancer patients. Knock-down of SNHG4 significantly reduced cell proliferation, colonization, migration, and invasion in vitro, as well as modulating the cell cycle and reduced tumor growth of endometrial cancer in vivo. In addition, the effect of SNHG4 by the transcription factor SP-1 was confirmed in vitro. We found in this study that SNHG4/SP-1 plays an important role in endometrial cancer progression and may be used as a potential therapeutic and prognostic biomarker for endometrial cancer.

The long non-coding RNA PVT1 promotes tumorigenesis of cutaneous squamous cell carcinoma via interaction with 4EBP1

The long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) plays an oncogenic role in multiple cancers due to its high expression. However, the expression and associated regulatory mechanisms of PVT1 in cutaneous squamous cell carcinoma (cSCC) remain unclear. Our results revealed that PVT1 was highly upregulated in cSCC tissues and cSCC cell lines. To determine the functional role of PVT1 in cSCC, we constructed a stable knockdown cell model of PVT1 in the A431 and COLO16 cell lines using a lentiviral approach. Xenograft tumor experiments of nude mice in vivo, and colony formation, CCK-8, and EdU assays in vitro demonstrated that knockdown of PVT1 could widely suppress cell proliferation in vivo and in vitro. In addition, PVT1 knockdown induced cell cycle arrest and promoted apoptosis, as detected by flow cytometry analysis. Wound healing and transwell assays revealed that PVT1 knockdown significantly inhibited the migration and invasion of CSCC cell lines. To gain insight into the tumorigenic mechanism and explore the potential target molecules of PVT1, we employed label-free quantitative proteomic analysis. The GO, KEGG enrichment, and protein-protein interaction (PPI) networks suggested that 4E-binding protein 1 (4EBP1) is the possible downstream target effector of PVT1, which was validated by western blot analysis. PVT1 silencing markedly decreased 4EBP1 protein expression levels and directly bound 4EBP1 in the cytoplasm of cSCC cells. 4EBP1 overexpression counteracted the effects of PVT1 knockdown on tumorigenesis in cSCC cells, including cell proliferation, apoptosis, migration, and invasion. Our findings provide strong evidence that PVT1 is an oncogene which plays a role in tumorigenesis of cSCC, that PVT1 may interact with 4EBP1 in the cytoplasm as an underlying mechanism in cSCC carcinogenesis, and that PVT1 combined with 4EBP1 may serve as a potential new therapeutic target for cSCC.

Aberrant expression of long non-coding RNA PVT1 in allergic rhinitis children: Correlation with disease risk, symptoms, and Th1/Th2 imbalance

BACKGROUND

Long non-coding RNA plasmacytoma variant translocation 1 (lnc-PVT1) exacerbates inflammation and induces T helper (Th) 1/Th2 imbalance in allergic diseases, but its clinical role in allergic rhinitis (AR) remains unclear. Hence, we conducted this study to compare lnc-PVT1 expression among AR children, disease controls (DCs), and health controls (HCs), aiming to investigate its clinical application in AR children.

METHODS

Sixty AR children, 30 DCs, and 30 HCs were enrolled in the study, and then, their lnc-PVT1 expression in peripheral blood mononuclear cell was detected. Serum interferon-gamma (IFN-γ), interleukin 10 (IL-10), Th1, and Th2 cells in AR children were also analyzed. Besides, lnc-PVT1 was also detected at Week (W)4 after treatment in AR patients.

RESULTS

Lnc-PVT1 was upregulated in AR children compared with DCs and HCs (both p < 0.001). Lnc-PVT1 was positively related to nasal rhinorrhea score, itching score, congestion score, and total nasal symptom score (TNSS) in AR children (all p < 0.050), instead of sneezing score (p = 0.115). Lnc-PVT1 negatively associated with Th1 cells in AR children (p = 0.028) also exhibited a negative correlation trend with IFN-γ (but without statistical significance) (p = 0.065). Differently, lnc-PVT1 was positively related to Th2 cells (p = 0.012) and IL-10 (p = 0.021) in AR children. Besides, lnc-PVT1 and TNSS were reduced at W4 after treatment in AR children (both p < 0.001); notably, lnc-PVT1 expression decline was correlated with TNSS decline during treatment (p = 0.013).

CONCLUSION

Lnc-PVT1 works as a biomarker, whose aberrant expression is related to disease severity, Th1/Th2 imbalance, and its decrement can reflect treatment outcome in AR children.

The lncRNA NEAT1/miRNA-766-5p/E2F3 Regulatory Axis Promotes Prostate Cancer Progression

Background

Prostate cancer (PCa) is one of the most common malignancies in men. Increasing evidence has demonstrated that dysregulation of long noncoding RNAs (lncRNAs) is closely related to carcinogenesis and cancer progression. lncRNA NEAT1 has recently been identified as a carcinogenic regulator of multiple cancers; however, the role of NEAT1 on PCa is still poorly understood.

Methods

Kaplan–Meier was conducted to determine the overall survival rate in PCa patients with aberrant NEAT1 levels. qRT-PCR analysis was performed to detect expressions of NEAT1 and miR-766-5p in tissues and cells. In addition, CCK-8, colony formation, flow cytometry analysis, wound healing, and transwell assay were conducted to determine cell proliferation, cell arrest, apoptosis, migration, and invasion. The western blot assay was utilized to determine E2F3 and cell growth-related proteins. The relationship between NEAT1 and miR-766-5p or miR-766-5p and E2F3 was verified by correlation analysis and dual-luciferase reporter assay.

Results

Here, we find that NEAT1 is overexpressed in PCa tissues and cell lines. Besides, silencing of NEAT1 inhibits cell proliferation, invasion, and migration and promotes cell apoptosis and cell cycle arrest. Further mechanistic studies find that NEAT1 sponges miR-766-5p, and miRNA-766-5p is negatively correlated with the expression of NEAT1. In addition, the functional experiment shows that upregulation of miRNA-766-5p inhibits PCa proliferation, migration, and invasion. Furthermore, E2F transcription factor 3 (E2F3) is testified to be the downstream target gene of miRNA-766-5p. Finally, the rescue experiment revealed that miRNA-766-5p inhibition largely restores NEAT1 downregulation-mediated function on PCa progression, while E2F3 knockdown partly removes the effects of miRNA-766-5p inhibitor.

Conclusions

In conclusion, NEAT1 facilitates PCa progression by targeting the miRNA-766-5p/E2F3 axis.

Association of lncRNA PVT1 Gene Polymorphisms with the Risk of Essential Hypertension in Chinese Population

Vascular dysfunction and hyperlipidemia are essential risk factors contributing to essential hypertension (EH). The plasmacytoma variant translocation 1 (PVT1) is involved in modulating angiogenesis in tumor tissues and plays an important role in fat differentiation in the progress of obesity. Therefore, we selected two tagSNPs of PVT1 (rs10956390 and rs80177647) to investigate whether they are contributing to the risk of hypertension in Chinese patients. In total, 524 adult patients with EH and 439 matched healthy controls were enrolled for two central of China. Results. PVT1 rs10956390 and rs80177647 polymorphisms were genotyped by using TaqMan assay. PVT1 rs10956390 TT genotype was associated with a decreased risk of EH (OR = 0.561, 95% CI = 0.372-0.846, P = 0.006), while rs80177647 TA genotype was associated with an increased risk (OR = 2.236, 95% CI = 1.515-3.301, P < 0.001). Rs10956390 T allele was associated with lower triglyceride levels in the plasma both from healthy and EH donors. What is more, there is an association between rs10956390 polymorphism and HDL-C level, as well as LDL-C. Conclusion. PVT1 rs10956390 and rs80177647 polymorphisms may contribute to the risk of EH in Chinese population by regulating blood lipid levels.

Mechanisms of Long Non-Coding RNAs in Biological Characteristics and Aerobic Glycolysis of Glioma

Glioma is the most common and aggressive tumor of the central nervous system. The uncontrolled proliferation, cellular heterogeneity, and diffusive capacity of glioma cells contribute to a very poor prognosis of patients with high grade glioma. Compared to normal cells, cancer cells exhibit a higher rate of glucose uptake, which is accompanied with the metabolic switch from oxidative phosphorylation to aerobic glycolysis. The metabolic reprogramming of cancer cell supports excessive cell proliferation, which are frequently mediated by the activation of oncogenes or the perturbations of tumor suppressor genes. Recently, a growing body of evidence has started to reveal that long noncoding RNAs (lncRNAs) are implicated in a wide spectrum of biological processes in glioma, including malignant phenotypes and aerobic glycolysis. However, the mechanisms of diverse lncRNAs in the initiation and progression of gliomas remain to be fully unveiled. In this review, we summarized the diverse roles of lncRNAs in shaping the biological features and aerobic glycolysis of glioma. The thorough understanding of lncRNAs in glioma biology provides opportunities for developing diagnostic biomarkers and novel therapeutic strategies targeting gliomas.

Prognostic and clinicopathological value of circPVT1 in human cancers: A meta-analysis

BACKGROUND

Circular RNA PVT1 (circPVT1) is significantly upregulated in various human cancers and is related to poor clinical outcome of cancer patients. However, the prognostic and clinicopathological value of circPVT1 in diverse human cancers remains controversial and inconclusive.

AIM

The objective of our study is to evaluate the prognostic and clinicopathological role of circPVT1 for cancer patients.

METHODS AND RESULTS

PubMed, Embase, Web of Science, and Cochrane Library were searched for eligible studies by October 1, 2020. The correlation between circPVT1 expression, and overall survival (OS) and clinical parameters was assessed by pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup analyses, heterogeneity, and publication bias were conducted to further enhance reliability. Twelve studies (1282 patients) were selected for this meta-analysis, including 11 on prognosis and 10 on clinicopathological parameters. Elevated expression of circPVT1 was associated with a worse OS in cancer patients (HR, 2.009; 95% CI, 1.667-2.408, 1.892; P < .001). For clinicopathological value, upregulation of circPVT1 was closely related to poor clinical parameters lymph node metastasis (OR = 2.019; 95% CI, 1.026-3.976; P = .042; I2  = 77.5%; PH  = 0.000), late clinical stage (OR = 3.594; 95% CI, 1.828-7.065; P < .001; I2  = 71.7%; PH  = 0.001), distant metastasis (OR = 4.598; 95% CI, 1.411-14.988; P = .011; I2  = 78.1%; PH  = 0.001), and chemoresistant (OR = 6.400; 95% CI, 2.107-19.441; P = .001; I2  = 49.6%; PH  = 0.159).

CONCLUSION

High expression of circPVT1 is correlated with unfavorable prognosis of cancer patients, indicating that circPVT1 can function as a potential prognostic biomarker in human cancer.

lncRNA SNHG22 sponges miR‑128‑3p to promote the progression of colorectal cancer by upregulating E2F3

The long non‑coding RNA (lncRNA) small nucleolar RNA host gene 22 (SNHG22) has been reported as a crucial regulator in several types of human cancer. The present study evaluated the function and mechanism of SNHG22 in colorectal cancer (CRC) progression. SNHG22 expression was detected in colorectal adenoma, CRC tumor tissues (TTs) and adjacent non‑cancerous tissues (ANTs) using reverse transcription‑quantitative PCR (RT‑qPCR). The biological behaviors of SNHG22 in CRC cell lines were explored in vitro using Cell Counting Kit‑8, flow cytometry, wound scratch assay and Transwell assay, and in vivo using a nude mouse xenograft model. The interaction between SNHG22 and microRNA‑128‑3p (miR‑128‑3p), and the target genes of miR‑128‑3p were explored using online tools, RT‑qPCR, western blotting and a dual‑luciferase reporter assay. The present study revealed that SNHG22 expression was most highly expressed in TTs followed by adenoma tissues and ANTs. In addition, high SNHG22 expression levels were significantly associated with advanced clinicopathological factors and worse survival in patients with CRC. SNHG22 knockdown markedly inhibited CRC cell proliferation, apoptosis resistance, migration and invasion in vitro, and hindered tumor growth in vivo. The mechanistic study revealed that SNHG22 bound to miR‑128‑3p and attenuated its inhibitory effects on E2F transcription factor 3 (E2F3) expression levels and activity. Rescue experiments demonstrated that inhibiting miR‑128‑3p or upregulating E2F3 offset the effects of SNHG22 knockdown on CRC cells. The present findings support the existence of an interactive regulatory network involving SNHG22, miR‑128‑3p and E2F3 in CRC cell lines, indicating that the SNHG22/miR‑128‑3p/E2F3 axis may be considered a novel diagnostic and therapeutic target in CRC.

Identification of an epithelial-mesenchymal transition related long non-coding RNA (LncRNA) signature in Glioma

Epithelial–mesenchymal transition (EMT)-related long non-coding RNAs (lncRNAs) may be exploited as potential therapeutic targets in gliomas. However, the prognostic value of EMT-related lncRNAs in gliomas is unclear. We obtained lncRNAs from The Cancer Genome Atlas and constructed EMT-related lncRNA co-expression networks to identify EMT-related lncRNAs. The Chinese Glioma Genome Atlas (CGGA) was used for validation. Gene set enrichment and principal component analyses were used for functional annotation. The EMT–lncRNA co-expression networks were constructed. A real-time quantitative polymerase chain reaction assay was performed to validate the bioinformatics results. A nine-EMT-related lncRNAs (HAR1A, LINC00641, LINC00900, MIR210HG, MIR22HG, PVT1, SLC25A21-AS1, SNAI3-AS1, and SNHG18) signature was identified in patients with glioma. Patients in the low-risk group had a longer overall survival (OS) than those in the high-risk group (P < 0.0001). Additionally, patients in the high-risk group showed no deletion of chromosomal arms 1p and/or 19q, isocitrate dehydrogenase wild type, and higher World Health Organization grade. Moreover, the signature was identified as an independent factor and was significantly associated with OS (P = 0.041, hazard ratio = 1.806). These findings were further validated using the CGGA dataset. The low- and high-risk groups showed different EMT statuses based on principal component analysis. To study the regulatory function of lncRNAs, a lncRNA-mediated ceRNA network was constructed, which showed that complex interactions of lncRNA–miRNA–mRNA may be a potential cause of EMT progression in gliomas. This study showed that the nine-EMT-related lncRNA signature has a prognostic value in gliomas.

HOXC13-AS Induced Extracellular Matrix Loss via Targeting miR-497-5p/ADAMTS5 in Intervertebral Disc

Background/Aims: LncRNAs are a new modulator in the development of intervertebral disc degeneration. However, the functional role and mechanism of HOXC13-AS in intervertebral disc degeneration remain unclear. Methods: qRT-PCR analysis was performed to measure the relative expression levels of HOXC13-AS and miR-497-5p, and the levels of IL-1β, IL-6, and TNF-α in the medium supernatant were analyzed by ELISA. The related mechanism between HOXC13-AS and miR-497-5p was detected by luciferase assays. Results: The results revealed that TNF-α and IL-1β induced HOXC13-AS expression in NP cells. HOXC13-AS was overexpressed in IDD specimens compared to control specimens, and higher expression of HOXC13-AS was correlated with high Pfirrmann scores. Ectopic expression of HOXC13-AS promoted MMP-3 and ADAMTS4 and inhibited aggrecan and collagen II expression in NP cells. Furthermore, overexpression of HOXC13-AS increased the expression of inflammatory cytokines, including IL-1β, IL-6, and TNF-α. Our results demonstrated that TNF-α and IL-1β induced ADAMTS5 expression and suppressed miR-497-5p expression. miR-497-5p was downregulated in IDD specimens compared to control specimens, and the lower expression of miR-497-5p was correlated with high Pfirrmann scores. The miR-497-5p level was negatively proportional to HOXC13-AS expression in IDD specimens. Luciferase analysis data indicated that ADAMTS5 was a direct target gene of miR-497-5p. HOXC13-AS induced inflammatory cytokine expression and ECM degradation by modulating miR-497-5p/ADAMTS5. Conclusion: HOXC13-AS may be a treatment target for IDD.

Overexpression of lncRNA SNGH3 Predicts Unfavorable Prognosis and Clinical Outcomes in Human Cancers: Evidence from a Meta-Analysis

Long noncoding RNAs (lncRNAs) have been confirmed to play a crucial role in human disease, especially in tumor development and progression. Small nucleolar RNA host gene (SNHG3), a newly identified lncRNA, has been found dysregulated in various cancers. Nevertheless, the results remain controversial. Thus, we aim to analyze the comprehensive data to elaborate the association between SNHG3 expression and clinical outcomes in multiple cancers. We searched PubMed, Web of Science, Cochrane Library, Embase, and MEDLINE database to identify eligible articles. STATA software was applied to calculate the hazard ratio (HR) and odds ratio (OR) with 95% confidence interval (95% CI) for survival outcomes and clinical parameters, respectively. Besides, the data from The Cancer Genome Atlas (TCGA) dataset was extracted to verify the results in our meta-analysis. There were thirteen studies totaling 919 cancer patients involved in this meta-analysis. The results demonstrated that high SNHG3 expression was significantly associated with poor overall survival (OS) (HR = 2.53, 95% CI: 1.94-3.31) in cancers, disease-free survival (DFS) (HR = 3.89, 95% CI: 1.34-11.3), and recurrence-free survival (RFS) (HR = 2.42, 95% CI: 1.14-5.15) in hepatocellular carcinoma. Analysis stratified by analysis method, sample size, follow-up time, and cancer type further verified the prognostic value of SNHG3. Additionally, patients with high SNHG3 expression tended to have more advanced clinical stage, higher histological grade, earlier distant metastasis, and earlier lymph node metastasis. Excavation of TCGA dataset valuated that SNHG3 was upregulated in various cancers and predicted worse OS and DFS. Overexpressed SNHG3 was strongly associated with poor survival and clinical outcomes in human cancers and therefore can serve as a promising biomarker for predicting patients' prognosis.

Atezolizumab and blockade of LncRNA PVT1 attenuate cisplatin resistant ovarian cancer cells progression synergistically via JAK2/STAT3/PD-L1 pathway

OBJECTIVE

To investigate the relationship between lncRNA PVT1(PVT1) level and PD-L1 expression and their functions in cisplatin resistant epithelial ovarian cancer (CREOC).

METHODS

PVT1 and PD-L1 in ovarian cancer tissues were detected and analyzed. The cells proliferation, apoptosis, invasion abilities and potential mechanism were detected by cell functional experiments and western-blot assay, respectively.

RESULTS

The average expressions of PVT1 and PD-L1 in CREOC tissues were significantly higher. The expression of PVT1 is positively associated with PD-L1 in CREOC. Higher expressions of PVT1 and PD-L1 indicated more malignant clinical behavior and shorter PFS and OS. Knockdown of PVT1 inhibited the proliferation and invasion and promote apoptosis for A2780cis cells, which may be related to decrease the expression of PD-L1 via repressing JAK2/STAT3 pathway.

CONCLUSIONS

The synergistic therapeutic strategy using LncRNA PVT1-targeted therapy and immune checkpoint blockade of PD-L1 warrant study further for ovarian cancer patients with cisplatin resistant recurrence.

LncRNA-PVT1 activates lung fibroblasts via miR-497-5p and is facilitated by FOXM1

It is little known about the lncRNA-PVT1 effect on occupational pulmonary fibrosis, although researches show it plays an essential role in cancer. Studies reveal that lung fibroblast activation is one of the key events in silica-induced fibrosis. Here, we found that lncRNA-PVT1 promoted the proliferation, activation, and migration of lung fibroblasts. The isolation of cytoplasmic and nuclear RNA assay and fluorescence in situ hybridization experiment showed that lncRNA-PVT1 was abundantly expressed in the cytoplasm. Luciferase reporter gene assay and RNA pull-down experiment indicated that the cytoplasmic-localized lncRNA-PVT1 could competitively bind miR-497-5p. MiR-497-5p was further observed to attenuate silica-induced pulmonary fibrosis by targeting Smad3 and Bcl2. Moreover, the transcription factor FOXM1 acted as a profibrotic factor by elevating lncRNA-PVT1 transcription in lung fibroblasts. Inhibition of FOXM1 expression with thiostrepton alleviated silica-induced pulmonary fibrosis in vivo. Collectively, we revealed that FOXM1-facilitated lncRNA-PVT1 activates lung fibroblasts via miR-497-5p during silica-induced pulmonary fibrosis, which may provide potential therapeutic targets for pulmonary fibrosis.

LINC00472 regulates vascular smooth muscle cell migration and proliferation via regulating miR-149-3p

LncRNAs are one group of gene modulators functioning via several mechanisms in pathological and physiological conditions. We noted that LINC00472 expression level is elevated in atherosclerotic coronary tissues compared with normal coronary artery samples. LINC00472 is also upregulated in vascular smooth muscle cells (VSMCs) induced by TNF-α and PDGF-BB. Ectopic expression of LINC00472 induced VSMC migration and proliferation. The predicted binding sequence between miR-149-3p and LINC00472 was analyzed by LncBase Predicted. Overexpression of miR-149-3p decreases the luciferase activity of wild-type reporter plasmid, but not the mutant one. Ectopic expression of LINC00472 suppresses the expression of miR-149-3p in VSMCs. Furthermore, we demonstrated that miR-149-3p expression is decreased in atherosclerotic coronary tissues. MiR-149-3p was downregulated in VSMCs induced by TNF-α and PDGF-BB. Overexpression of LINC00472 induces VSMC migration and proliferation via regulating miR-149-3p. These data suggested that LINC00472 acts a critical role in the migration and proliferation of VSMCs partly via modulating miR-149-3p.

PVT1 signals an androgen-dependent transcriptional repression program in prostate cancer cells and a set of the repressed genes predicts high-risk tumors

BACKGROUND

Androgen receptor (AR) and polycomb repressive complex 2 (PRC2) are known to co-occupy the loci of genes that are downregulated by androgen-stimulus. Long intergenic non-coding RNA (lincRNA) PVT1 is an overexpressed oncogene that is associated with AR in LNCaP prostate cancer cells, and with PRC2 in HeLa and many other types of cancer cells. The possible involvement of PVT1 in mediating androgen-induced gene expression downregulation in prostate cancer has not been explored.

METHODS

LNCaP cell line was used. Native RNA-binding-protein immunoprecipitation with anti-AR or anti-EZH2 was followed by RT-qPCR with primers for PVT1. Knockdown of PVT1 with specific GapmeRs (or a control with scrambled GapmeR) was followed by differentially expressed genes (DEGs) determination with Agilent microarrays and with Significance Analysis of Microarrays statistical test. DEGs were tested as a tumor risk classifier with a machine learning Random Forest algorithm run with gene expression data from all TCGA-PRAD (prostate adenocarcinoma) tumors as input. ChIP-qPCR was performed for histone marks at the promoter of one DEG.

RESULTS

We show that PVT1 knockdown in androgen-stimulated LNCaP cells caused statistically significant expression upregulation/downregulation of hundreds of genes. Interestingly, PVT1 knockdown caused upregulation of 160 genes that were repressed by androgen, including a significantly enriched set of tumor suppressor genes, and among them FAS, NOV/CCN3, BMF, HRK, IFIT2, AJUBA, DRAIC and TNFRSF21. A 121-gene-set (out of the 160) was able to correctly predict the classification of all 293 intermediate- and high-risk TCGA-PRAD tumors, with a mean ROC area under the curve AUC = 0.89 ± 0.04, pointing to the relevance of these genes in cancer aggressiveness. Native RIP-qPCR in LNCaP showed that PVT1 was associated with EZH2, a component of PRC2. PVT1 knockdown followed by ChIP-qPCR showed significant epigenetic remodeling at the enhancer and promoter regions of tumor suppressor gene NOV, one of the androgen-repressed genes that were upregulated upon PVT1 silencing.

CONCLUSIONS

Overall, we provide first evidence that PVT1 was involved in signaling a genome-wide androgen-dependent transcriptional repressive program of tumor suppressor protein-coding genes in prostate cancer cells. Identification of transcriptional inhibition of tumor suppressor genes by PVT1 highlights the pathway to the investigation of mechanisms that lie behind the oncogenic role of PVT1 in cancer. Video Abstract.

LncRNA ROR1-AS1 accelerates osteosarcoma invasion and proliferation through modulating miR-504

Long non-coding RNAs (LncRNAs) play vital roles in the progression and development of tumors. However, the functional role of ROR1-AS1 in osteosarcoma has not been investigated. We found that ROR1-AS1 was upregulated in osteosarcoma tissues compared to non-tumor samples. Elevated expression of ROR1-AS1 promoted cyclin D1, PCNA and ki-67 expression and increased cell cycle and growth in MG-63 cell. Moreover, overexpression of ROR1-AS1 induced cell migration in MG-63 cell, promoting N-cadherin and vimentin expression and inhibiting E-cadherin expression. Dual-luciferase assay proved that ROR1-AS1 served as one sponge for miR-504 and ROR1-AS1 overexpression suppressed miR-504 expression in MG-63 cell. ROR1-AS1 expression was lower in osteosarcoma tissues compared to non-tumor samples. Pearson's correlation assay showed a negative correlation between miR-504 and ROR1-AS1 expression. MiR-504 overexpression partly abrogated ROR1-AS1-induced effects on osteosarcoma cell migration and proliferation. These data implied that ROR1-AS1 played as an oncogene and might be a new treatment target for osteosarcoma.

Long Noncoding RNA PVT1 Is Regulated by Bromodomain Protein BRD4 in Multiple Myeloma and Is Associated with Disease Progression

Long noncoding RNAs (lncRNAs) are deregulated in human cancers and are associated with disease progression. Plasmacytoma Variant Translocation 1 (PVT1), a lncRNA, is located adjacent to the gene MYC, which has been linked to multiple myeloma (MM). PVT1 is expressed in MM and is associated with carcinogenesis. However, its role and regulation remain uncertain. We examined PVT1/MYC expression using real-time PCR in plasma cells purified from 59 monoclonal gammopathy of undetermined significance (MGUS) and 140 MM patients. The MM cell lines KMS11, KMS12PE, OPM2, and RPMI8226 were treated with JQ1, an MYC super-enhancer inhibitor, or MYC inhibitor 10058-F4. The expression levels of PVT1 and MYC were significantly higher in MM than in MGUS (p < 0.0001) and were positively correlated with disease progression (r = 0.394, p < 0.0001). JQ1 inhibited cell proliferation and decreased the expression levels of MYC and PVT1. However, 10054-F4 did not alter the expression level of PVT1. The positive correlation between MYC and PVT1 in patients, the synchronous downregulation of MYC and PVT1 by JQ1, and the lack of effect of the MYC inhibitor on PVT1 expression suggest that the expression of these two genes is co-regulated by a super-enhancer. Cooperative effects between these two genes may contribute to MM pathogenesis and progression.

The crosstalk between lncRNAs and the Hippo signalling pathway in cancer progression

LncRNAs play a pivotal role in the regulation of epigenetic modification, cell cycle, differentiation, proliferation, migration and other physiological activities. In particular, considerable studies have shown that the aberrant expression and dysregulation of lncRNAs are widely implicated in cancer initiation and progression by acting as tumour promoters or suppressors. Hippo signalling pathway has attracted researchers’ attention as one of the critical cancer‐related pathways in recent years. Increasing evidences have demonstrated that lncRNAs could interact with Hippo cascade and thereby contribute to acquisition of multiple malignant hallmarks, including proliferation, metastasis, relapse and resistance to anti‐cancer treatment. Specifically, Hippo signalling pathway is reported to modulate or be regulated by widespread lncRNAs. Intriguingly, certain lncRNAs could form a reciprocal feedback loop with Hippo signalling. More speculatively, lncRNAs related to Hippo pathway have been poised to become important putative biomarkers and therapeutic targets in human cancers. Herein, this review focuses on the crosstalk between lncRNAs and Hippo pathway in carcinogenesis, summarizes the comprehensive role of Hippo‐related lncRNAs in tumour progression and depicts their clinical diagnostic, prognostic or therapeutic potentials in tumours.

Population Differentiation at the PVT1 Gene Locus: Implications for Prostate Cancer

Genetic variation in susceptibility to complex diseases, such as cancer, is well-established. Enrichment of disease associated alleles in specific populations could have implications for disease incidence and prevalence. Prostate cancer (PCa) is a disease with well-established higher incidence, prevalence, and worse outcomes among men of African ancestry in comparison to other populations. PCa is a multi-factorial, complex disease, but the exact mechanisms for its development and progression are unclear. The gene desert located on chromosome 8q24 is associated with aggressiveness of PCa. Interestingly, the non-protein coding gene locus Plasmacytoma Variant Translocation (PVT1) is present at chromosome 8q24 and is overexpressed in PCa. PVT1 gives rise to multiple transcripts with potentially different molecular and cellular functions. In an analysis of the PVT1 locus using data from the 1000 Genomes Project, we found the chromosomal region spanning PVT1 exons 4A and 4B to be highly differentiated between African and non-African populations. We further investigated levels of gene expression of PVT1 exons 4A and 4B and observed significant overexpression of these exons in PCa tissues relative to benign prostatic hyperplasia and to normal prostate tissues obtained from men of African ancestry. These results indicate that PVT1 exons 4A and 4B may have clinical implications in PCa a conclusion supported by the observation that transient and stable overexpression of PVT1 exons 4A and 4B significantly induce greater prostate epithelial cell migration and proliferation. We anticipate that further exploration of the role of PVT1 exons 4A and 4B may lead to the development of diagnostic, therapeutic, and other clinical applications in PCa.

The prognostic value of lncRNA SNHG4 and its potential mechanism in liver cancer

BACKGROUND AND OBJECT

Emerging evidence shows that non-coding RNA functions as new gene regulators and prognostic markers in several cancers, including liver cancer. Here, we focused on the small nucleolar RNA host gene 4 (SNHG4) in liver cancer prognosis based on The Cancer Genome Atlas (TCGA) data.

METHODS

The expression data and clinical information were downloaded from TCGA. Chi-square tests evaluated the correlation between SNHG4 expression and clinical parameters. Differences in survival between high and low expression groups (optic cutoff value determined by ROC) from Cox regression analysis were compared, and P-value was calculated by a log-rank test. Kaplan-Meier curves were compared with the log-rank test. GSEA and ceRNA network were conducted to explore the potential mechanism.

RESULTS

Data mining of lncRNA expression data for 371 patients with primary tumor revealed overexpression of SNHG4 in liver cancer. High SNHG4 expression was correlated with histological type (P = 0.01), histologic grade (P = 0.001), stage (P = 0.01), T classification (P = 0.004) and survival status (P = 0.013). Patients with high SNHG4 expression had poor overall survival and relapse-free survival compared with those with low SNHG4 expression. Multivariate analysis identified SNHG4 as an independent prognostic factor of poor survival in liver cancer. GSEA revealed related signaling pathway and ceRNA network explored the further mechanism.

CONCLUSION

High SNHG4 expression is an independent predictor of poor prognosis in liver cancer.

Knockdown of long non-coding RNA plasmacytoma variant translocation 1 inhibits cell proliferation while promotes cell apoptosis via regulating miR-486-mediated CDK4 and BCAS2 in multiple myeloma

AIMS

This study aimed to investigate the effect of long non-coding RNA-plasmacytoma variant translocation 1 (lnc-Pvt1) knockdown on regulating cell proliferation and apoptosis, and to explore its molecular mechanism in multiple myeloma (MM).

METHODS

Lnc-Pvt1 expression was detected in MM cell lines (NCI-H929, U-266, LP-1 and RPMI-8226 cell lines) and human normal plasma cells. In U-266 cells and LP-1 cells, control shRNA and lnc-Pvt1 shRNA plasmids were transferred. Rescue experiments were further performed by transfection of lnc-Pvt1 shRNA alone and lnc-Pvt1 shRNA and miR-486 shRNA plasmids. Cells proliferation, apoptosis, RNA expression, and protein expression were determined by cell counting kit-8, annexin V-FITC-propidium iodide, quantitative polymerase chain reaction, and Western blot assays, respectively.

RESULTS

Lnc-Pvt1 expression was increased in MM cell lines (NCI-H929, U-266 and LP-1 cell lines) compared with human normal plasma cells. In U-266 cells, lnc-Pvt1 shRNA suppressed cell proliferation while enhanced cell apoptosis compared with control shRNA. Also, lnc-Pvt1 shRNA increased miR-486 expression compared with control shRNA. Further rescue experiment revealed that miR-486 shRNA did not change lnc-Pvt1 level, but increased CDK4 and BCAS2 expressions in lnc-Pvt1 knockdown-treated cells. In addition, miR-486 shRNA promoted cell proliferation while inhibited cell apoptosis in lnc-Pvt1 knockdown-treated cells. These results were further validated in LP-1 cells.

CONCLUSIONS

Lnc-Pvt1 knockdown inhibits cell proliferation and induces cell apoptosis through potentially regulating miR-486-mediated CDK4 and BCAS2 in MM.

Clinicopathological and prognostic value of LINC01296 in cancers: a meta-analysis

Objective: The long intergenic non-coding RNA 01296 (LINC01296) has been reported to be overexpressed in multiple tumours. However, the role of LINC01296 in clinicopathologic and prognostic value in cancers remains completely unknown. The aim of the present meta-analysis was to comprehensively elucidate the correlation between LINC01296 with clinicopathological features and survival outcomes in tumours. Methods: Electronic databases of PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Database were used to search relevant studies. The role of LINC01296 in cancers was evaluated by pooled hazard ratios (HRs), odds ratios (ORs) and 95% confidence intervals (CIs). Results: In total, nine studies compromising 720 participants were enrolled in this analysis. The pooled results showed increased LINC01296 expression could predict unfavourable overall survival (OS) (HR = 1.89, 95%CI = 1.47-2.43, p < .001). Additionally, elevated LINC01296 expression was correlated with clinical stage (OR = 2.95, 95%CI = 2.13-4.08, p < .001), lymph node metastasis (OR = 2.76, 95%CI = 2.00-3.81, p < .001), tumour size (OR = 2.80, 95%CI = 1.77-4.41, p < .001), and tumour differentiation (OR = 2.11, 95%CI = 1.36-3.27, p < .001) in patients with cancers. Conclusion: The results of this meta-analysis indicated LINC01296 was a novel biomarker for prognosis and clinicopathological parameters in cancers.

Long non-coding RNA PVT1 encapsulated in bone marrow mesenchymal stem cell-derived exosomes promotes osteosarcoma growth and metastasis by stabilizing ERG and sponging miR-183-5p

Exosomes secreted by bone marrow mesenchymal stem cells (BMSCs) promote osteosarcoma cell proliferation and migration, while the underlying mechanism remains unknown. Since the long non-coding RNA PVT1 has been reported to be upregulated in osteosarcoma cells and contributes to its growth and metastasis, we aim to investigate whether BMSC-derived exosomes promote osteosarcoma growth and metastasis via transporting PVT1 into osteosarcoma cells. The PVT1 expression in BMSC-derived exosomes was markedly higher than that in osteosarcoma cell-derived exosomes. The co-culturing of BMSC-derived exosomes and osteosarcoma cells (Saos-2, MG-63, and MNNG/HOS cell lines) significantly raised PVT1 expression of osteosarcoma cells. The direct binding between PVT1 and the oncogenic protein ERG was confirmed using RNA immunoprecipitation and RNA pull-down assays, and the transported PVT1 promotes osteosarcoma cell proliferation and migration via inhibiting degradation and ubiquitination of ERG. PVT1 also increased ERG expression through sponging miR-183-5p. In summary, our findings indicated that BMSC-derived exosomes encapsulate PVTl and transport it into osteosarcoma cells, and the transported PVT1 promotes tumor growth and metastasis by inhibiting ubiquitination and promoting expression of ERG in osteosarcoma cells. These data provide a novel insight into the mechanism of BMSC-derived exosomes in affecting osteosarcoma progression.

Long non-coding RNA PVT1 interacts with MYC and its downstream molecules to synergistically promote tumorigenesis

Numerous studies have shown that non-coding RNAs play crucial roles in the development and progression of various tumor cells. Plasmacytoma variant translocation 1 (PVT1) mainly encodes a long non-coding RNA (lncRNA) and is located on chromosome 8q24.21, which constitutes a fragile site for genetic aberrations. PVT1 is well-known for its interaction with its neighbor MYC, which is a qualified oncogene that plays a vital role in tumorigenesis. In the past several decades, increasing attention has been paid to the interaction mechanism between PVT1 and MYC, which will benefit the clinical treatment and prognosis of patients. In this review, we summarize the coamplification of PVT1 and MYC in cancer, the positive feedback mechanism, and the latest promoter competition mechanism of PVT1 and MYC, as well as how PVT1 participates in the downstream signaling pathway of c-Myc by regulating key molecules. We also briefly describe the treatment prospects and research directions of PVT1 and MYC.

Long non-coding RNA PVT1, a molecular sponge of miR-26b, is involved in the progression of hyperglycemia-induced collagen degradation in human chondrocytes by targeting CTGF/TGF- signal ways

The current study was conducted to investigate the role of long non-coding RNA PVT1 in hyperglycemia-triggered human osteoarthritis (OA) chondrocytes. Cartilage from knee OA patients with and without diabetes, as well as normal cartilage, was obtained. Isolated human chondrocytes were treated with 30 nM of Glc with or without pioglitazone. The expression levels of PVT1, miR-26b, and type II collagen were determined by RT-PCR. Type II collagen was detected by immunocytochemistry and chondrocytes were stained with Alcian blue. Moreover, the interaction among PVT1, miR-26b, and CTGF was examined using bioinformatics, FISH, RIP, RNA-pull down, and luciferase reporter assays. Over-expression of PVT1 and miR-26b were performed and expressions of CTGF, TGF-β1, SMAD3, MMP-13, and type II collagen proteins were examined. Significantly higher expression of PVT1 was observed in diabetic OA. High Glc induced the elevated expression of PVT1, CTGF, TGF-β1, IL-6, and MMP-13, as well as decreased expression of type II collagen and miR-26b. These alterations could be reversed by pioglitazone. PVT1 acted as a sponge for miR-26b to facilitate CTGF expression. Over-expression of PVT1 increased the expressions of CTGF, TGF-β1, SMAD3, and MMP-13 and decreased expression of type II collagen. Our findings confirmed that PVT1 is involved in the hyperglycemia-induced collagen degradation, via the miR-26b-CTGF-TGF-β1-axis.

Comprehensive investigation of the clinical significance and molecular mechanisms of plasmacytoma variant translocation 1 in sarcoma using genome-wide RNA sequencing data

Objective: The present study aims to identify the potential clinical application and molecular mechanism of plasmacytoma variant translocation 1 (PVT1) in patients with sarcomas by mining an RNA sequencing dataset from The Cancer Genome Atlas (TCGA) through multiple genome-wide analysis approaches.

Methods: A genome-wide RNA sequencing dataset was downloaded from TCGA, survival analysis was used to evaluate the prognostic value of PVT1 in sarcoma. The potential mechanism was investigated by multiple tools: Database for Annotation, Visualization, and Integrated Discovery v6.8, gene set enrichment analysis (GSEA), and Connectivity Map (CMap).

Results: Comprehensive survival analysis indicated that overexpression of PVT1 was significantly associated with poor prognosis in patients with sarcoma, and nomogram demonstrated that PVT1 contributed more than other traditional clinical parameters in sarcoma survival prediction. Weighted gene co-expression network analysis identified ten hub differentially expressed genes (DEGs) between sarcoma tissues with low and overexpression of PVT1, and substantiated that these DEGs have a complex co-expression network relationship. CMap analysis has identified that antipyrine, ondansetron, and econazole may be candidate targeted drugs for sarcoma patients with PVT1 overexpression. GSEA revealed that overexpression of PVT1 may be involved in the posttranscriptional regulation of gene expression, tumor invasiveness and metastasis, osteoblast differentiation and development, apoptosis, nuclear factor kappa B, Wnt, and apoptotic related signaling pathways.

Conclusions: Our findings indicate that PVT1 may serve as a prognostic indicator in patients with sarcoma. Its underlying mechanism is revealed by GSEA, and CMap offers three candidate drugs for the individualized targeted therapy of sarcoma patients with overexpression of PVT1.

PVT1 Signaling Is a Mediator of Cancer Progression

There is increasing evidence that PVT1 has oncogenic properties and regulates proliferation and growth of many cancers. Themolecular mechanisms of action of PVT1 are mediated, in part, by microRNAs (miRNAs). However, some well-established transcription factors involved in cancer cell proliferation share a common thread of microRNA associations with PVT1. Furthermore, these microRNAs are also involved in mechanisms that lead to the development of drug resistance in cancer cells. While several microRNAs have been implicated directly in PVT1-mediated tumorigenesis, significant steps need to be taken to elucidate these important relationships. We synthesize the current knowledge of the miRNAs and associated genes by which PVT1 contributes to tumorigenesis. Overall, the trend suggests a negative correlation of microRNA expression with PVT1. It is clear that future studies involving PVT1 should be carried out in conjunction with microRNA analysis and should include large scale lncRNA-miRNA-mRNA network analysis. Likewise, the relationship between established transcription factors such as p53 and MYC, and processes like epithelial-mesenchymal transition may offer valuable insight into the yet unknown mechanisms of PVTI-mediated cancer progression via microRNA-dependent signaling networks.

Prognostic values of long noncoding RNA PVT1 in various carcinomas: An updated systematic review and meta-analysis

Cancers have been a worldwide health problem with a high mortality rate, but ideal biomarkers are not available to effectively screen and diagnose patients. Currently, an increasing number of long noncoding RNAs have been reported to be abnormally expressed in human carcinomas and play a vital role in tumourigenesis. Plasmacytoma variant translocation 1 (PVT1) is upregulated in various carcinomas, and its overexpression is associated with poor survival in cancer patients. We conduct an updated meta-analysis to determine its potential in prognosis for tumours. In total, 14 studies comprising 2435 patients were enrolled according to Reporting Recommendations for Tumour Marker Prognostic Studies guidelines. High PVT1 expression indicated poor overall survival (hazard ratio [HR] = 1.98, 95% confidence interval [CI]: 1.62-2.42, P < 0.00001) and disease-free survival (HR = 1.63, 95% CI: 1.45-1.84, P < 0.00001). Additionally, increased PVT1 expression was positively associated with lymphatic node metastasis (odd ratio [OR] = 2.87, 95% CI: 1.66-4.96, P = 0.0002), distant metastasis (OR = 2.47, 95% CI: 1.74-3.50, P < 0.00001), advanced tumour-node-metastasis stages (OR = 2.59, 95% CI: 1.38-4.88, P = 0.003). New findings highlight that PVT1 acts as competing RNA to microRNAs to protect mRNAs from miRNAs repression. Therefore, we also discuss PVT1-related microRNAs and their interaction in tumourigenesis. In conclusion, PVT1 may be a potential biomarker of poor prognosis for patients with different cancer types.