Plasmacytoma Variant Translocation 1 Expression Research Articles

Abstract PR014: PVT1 fusion on extrachromosomal DNA (ecDNA) increases oncogene RNA stability and cancer cell growth

Abstract Extrachromosomal DNA (ecDNA), highly amplified circular DNA, is widespread in human cancers and serves as a primary location for oncogene amplification. Due to its dynamic structural rearrangement and asymmetric inheritance during cell division, ecDNA increases tumor genome complexity, contributing to drug resistance and shortened patient survival. Here, we show that ecDNA-mediated genomic amplification is highly associated with transcript fusion events, which are prevalent in cancer and often lead to tumor development. We discovered that transcripts with the highest fusion events originate from genes amplified on ecDNA across ecDNA(+) cell lines. Notably, PVT1 (Plasmacytoma Variant Translocation 1) long noncoding RNA, which is known to be a hotspot for chromosomal translocation, is the most frequently fused RNA species in MYC/PVT1-amplified ecDNA(+) cancer cells. Exon 1 of PVT1 is the predominant fusion partner and confers RNA stability, increasing the RNA abundance of the partner oncogene. Using a model cell line with PVT1-MYC fusion on ecDNA, we found that RNA expression of PVT1-MYC increases in vivo in an ecDNA-dependent manner, while canonical MYC does not show a prominent increase. Additionally, ectopic expression of PVT1- MYC in MYC-depleted cancer cells provides higher rescue efficiency than canonical MYC. In contrast, a PVT1-MYC mutant that is unable to enhance RNA stability fails to rescue, highlighting the functional significance of PVT1-mediated RNA stabilization in cancer. This study unveils the link between PVT1 fusion and ecDNA in cancer, providing insights for developing diagnostic and therapeutic approaches tailored to target ecDNA. Citation Format: Hyerim Yi, Shu Zhang, Matthew G Jones, Julia A Belk, Jason Swinderman, Quanming Shi, Ellis J Curtis, Vishnu P Kanakaveti, Paul S Mischel, Howard Y Chang. PVT1 fusion on extrachromosomal DNA (ecDNA) increases oncogene RNA stability and cancer cell growth [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr PR014.

LncRNA PVT1 facilitates the growth and metastasis of colorectal cancer by sponging with miR-3619-5p to regulate TRIM29 expression.

Colorectal cancer (CRC) is the second most common cause of cancer-related death worldwide. Long noncoding RNA (lncRNA) is involved in many malignant tumors. This study aimed to clarify the role of the lncRNA plasmacytoma variant translocation 1 (PVT1) in CRC growth and metastasis. Differentially expressed lncRNAs in CRC were analyzed using the Cancer Genome Atlas. Gene expression profiling interactive analysis and a comprehensive resource for lncRNAs from cancer arrays databases were used to analyze lncRNA PVT1 expression and CRC prognosis, respectively. Cell counting kit-8, wound healing, colony formation, Transwell, and immunofluorescence assays were used to evaluate CRC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT), respectively. Tumor growth and metastasis models were used to explore the PVT1 effect on the growth and metastasis of CRC in vivo. PVT1 was highly expressed in CRC, associated with a poor prognosis of CRC, and showed good diagnostic value. Transfection of sh-PVT1 or pcDNA3.1-PVT1 reduced or increased the proliferation, wound healing rate, colony formation, invasion, and EMT of CRC cells. PVT1 and miR-3619-5p were co-expressed in CRC cytoplasm, and PVT1 acted as a competitive endogenous RNA (ceRNA) by sponging miR-3619-5p to up-regulate tripartite motif containing 29 (TRIM29) expression. MiR-3619-5p overexpression and TRIM29 knockdown reduced proliferation, wound healing rate, invasion, and EMT of CRC cells. However, simultaneous PVT1 and miR-3619-5p overexpression or knockdown of miR-3619-5p and TRIM29 knockdown rescued the malignant phenotype of CRC cells. We first clarified the ceRNA mechanism of PVT1 in CRC, which induced growth and metastasis by sponging with miR-3619-5p to regulate TRIM29.

LncRNA-PVT1 Inhibits Ferroptosis through Activating STAT3/GPX4 Axis to Promote Osteosarcoma Progression.

Osteosarcoma (OS) is a primary malignant bone tumor in the pediatric and adolescent populations. Long non-coding RNAs (LncRNAs), such as plasma-cytoma variant translocation 1 (PVT1), have emerged as significant regulators of OS metastasis. Recent studies have indicated that activation of signal transducer and activator of transcription 3 (STAT3) signaling, which might be controlled by PVT1, inhibits ferroptosis to promote the malignant progression of cancer. Therefore, the present study aimed to determine the role of PVT1 in OS pathogenesis and investigate whether PVT1 affects OS progression by regulating STAT3/GPX4 pathway-mediated ferroptosis. The human OS cell line MG63 were transfected with sh-PVT1 plasmid to inhibit PVT1 expression, with or without co-transfection with a STAT3 overexpression plasmid. The expression of PVT1 was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The proliferation, migration, invasion, and apoptosis of MG63 cells were determined using the cell counting kit-8 (CCK8), Transwell assay, and flow cytometry. The levels of malondialdehyde (MDA), Fe2+, and glutathione (GSH) were determined by ELISA kits, whereas reactive oxygen species (ROS) level was determined by immunofluorescence. The protein expression levels of STAT3, p-STAT3, and glutathione peroxidase 4 (GPX4) were detected by western blot (WB). PVT1 expression was significantly increased in MG63 cells. When knocking down PVT1 with sh-PVT1 plasmid, the proliferation, migration, and invasion of MG63 cells were markedly inhibited, while the rate of apoptosis was upregulated. Further investigation revealed that MG63 cells with PVT1 knockdown exhibited elevated levels of MDA, Fe2+, and ROS. In addition, the inhibition of PVT1 expression resulted in decreased levels of GSH and inhibited expression of p-STAT3 and GPX4. When sh-PVT1 was co-transfected with STAT3 overexpression plasmid in MG63 cells, the increased levels of MDA, Fe2+, and ROS were downregulated, and the decreased expressions of GSH, p-STAT3, and GPX4 were upregulated. PVT1 promotes OS metastasis by activating the STAT3/GPX4 pathway to inhibit ferroptosis. Targeting PVT1 might be a novel therapeutic strategy for OS treatment.

Expression of PVT-1 and miR-29a/29b as reliable biomarkers for liver cirrhosis and their correlation with the inflammatory biomarkers profile.

The liver is a vital organ responsible for numerous metabolic processes, which can be significantly impacted by long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). These ribonucleic acid (RNA) molecules have been shown to play a crucial role in regulating gene expression, and their dysregulation has been implicated in numerous liver disorders. Our study aimed to investigate the diagnostic accuracy of plasmacytoma variant translocation-1 (PVT-1), microRNA-29a/29b (miR-29a/miR-29b), and inflammatory biomarkers [ interleukine-6 (IL-6), tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), and insulin growth factor-1 (IGF-1)] as diagnostic and prognostic biomarkers for liver cirrhosis. Therefore, understanding the mechanisms by which lncRNAs and miRNAs influence liver metabolism is of paramount importance in developing effective treatments for liver-related diseases. Serum samples were collected from 164 participants, comprising 114 cirrhotic patients with varying grades (35 grade I, 35 grade II, and 44 grade III) and 50 healthy controls. PVT-1 and miR-29a/miR-29b expression was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-PCR), while the serum levels of inflammatory biomarkers were assessed using enzyme-linked immunosorbent assay (ELISA). The study participants exhibited notable differences in PVT-1 and miR-29a/miR-29b expression. ROC analysis revealed excellent discriminative power for PVT-1 and miR-29a/miR-29b in distinguishing cirrhotic patients from healthy controls. This study demonstrates the promising potential of PVT-1 and miR-29a/miR-29b as early diagnostic biomarkers for liver cirrhosis detection, requiring further validation in larger cohorts. Our findings also reinforce the diagnostic value of circulating inflammatory biomarkers (IL-6, TNF-α, TGF-β, and IGF-1) levels for liver cirrhosis screening.

PVT1 promotes proliferation and macrophage immunosuppressive polarization through STAT1 and CX3CL1 regulation in glioblastoma multiforme.

This study aimed to investigate the role of plasmacytoma variant translocation 1 (PVT1), a long non-coding RNA, in glioblastoma multiforme (GBM) and its impact on the tumor microenvironment (TME). We assessed aberrant PVT1 expression in glioma tissues and its impact on GBM cell growth invitro and invivo. Additionally, we investigated PVT1's role in influencing glioma-associated macrophages. To understand PVT1's role in cell growth and the immunosuppressive TME, we performed a series of comprehensive experiments. PVT1 was overexpressed in GBM due to copy number amplification, correlating with poor prognosis. Elevated PVT1 promoted GBM cell proliferation, while its downregulation inhibited growth invitro and invivo. PVT1 inhibited type I interferon-stimulated genes (ISGs), with STAT1 as the central hub. PVT1 correlated with macrophage enrichment and regulated CX3CL1 expression, promoting recruitment and M2 phenotype polarization of macrophages. PVT1 localized to the cell nucleus and bound to DHX9, enriching at the promoter regions of STAT1 and CX3CL1, modulating ISGs and CX3CL1 expression. PVT1 plays a significant role in GBM, correlating with poor prognosis, promoting cell growth, and shaping an immunosuppressive TME via STAT1 and CX3CL1 regulation. Targeting PVT1 may hold therapeutic promise for GBM patients.

Long non-coding RNA PVT1 (PVT1) affects the expression of CCND1 and promotes doxorubicin resistance in osteosarcoma cells

BackgroundAcquired drug-resistance is the major risk factor for poor prognosis and short-term survival in patients with osteosarcoma (OS). Accumulating evidence has revealed that long noncoding RNAs (lncRNAs), including plasmacytoma variant translocation 1 (PVT1), play potential regulatory roles in the malignant development of OS. Considering the subcellular distribution of PVT1 as both nuclear and cytoplasmic lncRNA, a thorough exploration of its extensive mechanisms becomes essential. MethodsThe GEO database was utilized for the acquisition of gene expression data, which was subsequently analyzed to fulfill the research objectives. The subcellular localization of PVT1 in OS cells was determined using fluorescence in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, the sensitivity of OS cells to doxorubicin was comprehensively evaluated through measurements of cell viability, site-specific proliferation capacity, and the relative expression abundance of multidrug resistance-related proteins (MRPs). In order to investigate the differential response of OS cells with varying levels of PVT1 expression to doxorubicin, pulmonary metastasis mice models were established for in vivo studies. Molecular interactions were further examined using the dual-luciferase assay and RNA immunoprecipitation assay (RIP) to analyze the binding sites of miR-15a-5p and miR-15b-5p on PVT1 and G1/S-specific cyclinD1 (CCND1) mRNA. Furthermore, the chromatin immunoprecipitation (ChIP) and dual-luciferase assay were employed to assess the transcriptional activation of the proto-oncogene c-myc (MYC) on the CCND1 promoter and identify the corresponding binding sites. ResultsIn doxorubicin resistant OS cells, transcription levels of PVT1, MYC and CCND1 were significantly higher than those in original cells. In vivo experiments demonstrated that OS cells rich in PVT1 expression exhibited enhanced tumorigenicity and resistance to doxorubicin. In vitro experiments, it has been observed that overexpression of PVT1 in OS cells is accompanied by an upregulation of CCND1, thereby facilitating resistance to doxorubicin. Nonetheless, this PVT1-induced resistance can be effectively attenuated by the knockdown of CCND1. Mechanistically, PVT1 functions as a competitive endogenous RNA (ceRNA) that influences the expression of CCND1 by inhibiting the degradation function of miR-15a-5p and miR-15b-5p on CCND1 mRNA. Additionally, as a neighboring gene of MYC, PVT1 plays a role in maintaining MYC protein stability, which further enhances MYC-dependent CCND1 transcriptional activity. ConclusionThe resistance of OS cells to doxorubicin is facilitated by PVT1, which enhances the expression of CCND1 through a dual mechanism. This findings offer a novel perspective for comprehending the intricate regulatory mechanisms of long non-coding RNA in influencing the expression of coding genes.

Long noncoding RNA plasmacytoma variant translocation1 is overexpressed in cutaneous squamouscell carcinoma and exon 2 is critical for itsoncogenicity.

Cutaneous squamous cell carcinoma (cSCC) is one of the most common and fastest increasing forms of cancer worldwide with metastatic potential. Long noncoding RNAs (lncRNAs) are a group of RNA molecules with essential regulatory functions in both physiological and pathological processes. To investigate the function and mode of action of lncRNA plasmacytoma variant translocation 1 (PVT1) in cSCC. Quantitative reverse transcriptase polymerase chain reaction and single-molecule in situ hybridization were used to quantify the expression level of PVT1 in normal skin, premalignant skin lesions, actinic keratosis (AK) and primary and metastatic cSCCs. The function of PVT1 in cSCC was investigated both in vivo (tumour xenografts) and in vitro (competitive cell growth assay, 5-ethynyl-2'-deoxyuridine incorporation assay, colony formation assay and tumour spheroid formation assay) upon CRISPR-Cas9-mediated knockout of the entire PVT1 locus, the knockout of exon 2 of PVT1, and locked nucleic acid (LNA) gapmer-mediated PVT1 knockdown. RNA sequencing analysis was conducted to identify genes and processes regulated by PVT1. We identified PVT1 as a lncRNA upregulated in cSCC in situ and cSCC, associated with the malignant phenotype of cSCC. We showed that the expression of PVT1 in cSCC was regulated by MYC. Both CRISPR-Cas9 deletion of the entire PVT1 locus and LNA gapmer-mediated knockdown of PVT1 transcript impaired the malignant behaviour of cSCC cells, suggesting that PVT1 is an oncogenic transcript in cSCC. Furthermore, knockout of PVT1 exon 2 inhibited cSCC tumour growth both in vivo and in vitro, demonstrating that exon 2 is a critical element for the oncogenic role of PVT1. Mechanistically, we showed that PVT1 was localized in the cell nucleus and its deletion resulted in cellular senescence, increased cyclin-dependent kinase inhibitor 1 (p21/CDKN1A) expression and cell cycle arrest. Our study revealed a previously unrecognized role for exon 2 of PVT1 in its oncogenic role and that PVT1 suppresses cellular senescence in cSCC. PVT1 may be a potential biomarker and therapeutic target in cSCC.

Abstract 3804: Linear PVT1 isoforms and circPVT1 regulate DNA damage response and immunological pathways in acute myeloid leukemia and have a potential role in the crosstalk between leukemic cells and the tumor microenvironment

Abstract The human Plasmacytoma Variant Translocation 1 (PVT1) gene encodes for 176 linear (PVT1, lncipedia.org) and 29 circular isoforms (circPVT1, www.circbase.org). The most common isoform of circPVT1 is 410bp and is a product of back-splicing containing the whole exon 2 of PVT1 in a closed loop-like structure (hsa_circ_0001821). PVT1 and circPVT1 have oncogenic roles in several tumor types and can contribute to the suppression of anti-tumor immune responses. Our study aims to investigate whether and how PVT1 isoforms and circPVT1 promote an aggressive phenotype in acute myeloid leukemia (AML) and are involved in the crosstalk between leukemic and immune cells. Six out of the 14 PVT1 isoforms expressed by white blood cells and lymphnodes (noncode.org) were detected in a panel of AML cell lines along with circPVT1. Downregulation (KD) of groups of linear isoforms (based on sequence homology) or of circPVT1 by antisense-oligonucleotides (ASOs) in the t(8;21) KASUMI-1 and the NPM1-mut OCI-AML3 cells induced an impairment of leukemia cell growth especially when all the 6 linear isoforms were silenced by ASO combination, in both cell lines, under normoxia and hypoxia mimicking the bone-marrow microenvironment. Interestingly circPVT1-KD induced apoptosis in OCI-AML3 cells. Moreover, MYC protein expression decreased by ASO combination or circPVT1_KD in OCI-AML3 under normoxia and in KASUMI-1 under hypoxia. To further investigate the biological consequences of PVT1/circPVT1-KD, we performed RNAseq. Analysis on AML cell lines revealed that downregulation of PVT1 and, especially circPVT1, altered the expression of genes involved in RNA transport and degradation, as expected for a long non-coding genes, but also in DNA damage response (DDR) and immunological pathways, as also confirmed by transcriptomic data of primary AML cases and proteomic analysis of both cell lines. Based on these novel findings, we tested the downregulation of PVT1/circPVT1 in combination with inhibition of ATM or ATR, key DDR transducers. Interestingly, circPVT1-KD sensitized OCI-AML3 to ATM (71% vs 95% live cells) or ATR (75% vs 90% live cells) inhibitors. PVT1 and circPVT1 expression was also detected at the level of cell-free RNA in primary AML samples, the latter showing higher levels. We then analyzed extracellular vesicles (EVs) from AML peripheral blood and healthy subjects. EVs from patients were larger, increased in number and expressed higher levels of myeloid lineage markers. Finally AML EVs had more circPVT1 cargo. In conclusion, we uncovered novel potential roles of PVT1 isoforms and circPVT1 in the DDR and in the tumor microenvironment that pave the way for novel therapeutic combinations. Citation Format: Martina Ghetti, Lorenzo Ledda, Ivan Vannini, Eugenio Fonzi, Maria Teresa Bochicchio, Tristan Cardon, Andrea Ghelli Luserna di Rorà, Matteo Paganelli, Chiara Servili, Francesco Fabbri, Sabina Marianini, Giovanni Marconi, Michela Rondoni, Roberta Chicchi, Rino Biguzzi, Francesco Lanza, Michel Salzet, Giovanni Martinelli, Giorgia Simonetti. Linear PVT1 isoforms and circPVT1 regulate DNA damage response and immunological pathways in acute myeloid leukemia and have a potential role in the crosstalk between leukemic cells and the tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3804.

PVT1/miR-16/CCND1 axis regulates gastric cancer progression.

Long non-coding RNA plasmacytoma variant translocation 1 (PVT1) has been reported to be a vital modulator in tumorigenesis of gastric cancer (GC). However, the detailed regulatory mechanism of PVT1 in GC remains largely unclear. In this work, the expressions of PVT1 and microRNA-16 (miR-16) were detected by quantitative real-time PCR (qRT-PCR) in GC tissues and cell lines. GC cell lines NCI-N87 and MKN45 cell lines were chosen for the following assays. After PVT1 was overexpressed or depleted, CCK-8 and Transwell assays were performed to examine the cell viability and invasive capacity. Cell cycle was analyzed by flow cytometry. The expression of cyclin D1 (CCND1) at mRNA and protein levels was measured by qRT-PCR and western blot. The competitive endogenous RNA molecular mechanism among PVT1, miR-16 and CCND1 was verified by bioinformatics analysis, luciferase-reporter gene assay and RNA immunoprecipitation assay. In the present study, it was revealed that PVT1 expression was remarkably evaluated in GC tissues and cell lines than that in the corresponding control group. PVT1 positively regulated the proliferation, migration and cell cycle progression of GC cells. Besides, miR-16 was identified as a target of PVT1, and CCND1 was identified as a target of miR-16. The depletion of PVT1 promoted the expression of miR-16 and suppressed CCND1 expression. Moreover, either miR-16 inhibitor or CCND1 overexpression plasmid could reverse the promoting effects of PVT1 on the malignant biological behaviors of GC cells. In conclusion, PVT1 promoted CCND1 expression by negatively regulating miR-16 expression to enhance the viability, invasion and cell cycle progression of GC cells.

Diagnostic and Prognostic Value of Deregulated Long Non-Coding RNA Plasmacytoma Variant Translocation 1 in Patients with Gestational Hypertension.

This study aimed to investigate the serum plasmacytoma variant translocation 1 (PVT1) level in pregnant women with gestational hypertension and pre-eclampsia and its diagnostic value for diseases and its influence on pregnancy outcome. Serum PVT1 levels in 72 pregnant women with gestational hypertension, 72 pregnant women with pre-eclampsia and 71 healthy pregnant women were evaluated by RT-qPCR, and the diagnostic significance of PVT1 for gestational hypertension was verified by receiver operator characteristic (ROC) curve. The correlation between PVT1 and clinical indicators were evaluated by Pearson correlation coefficient method. Logistic regression analysis evaluated the influencing factors in the development process of gestational hypertension to pre-eclampsia. The effect of PVT1 level on pregnancy outcome was evaluated by prognostic analysis. Results showed that PVT1 level was down-regulated in gestational hypertension group compared with healthy control group, whereas PVT1 level was down-regulated more significantly in pre-eclampsia group than in gestational hypertension group. ROC curve showed that PVT1 had high diagnostic accuracy for gestational hypertension. Pearson correlation coefficient and multiple linear regression analysis showed that PVT1 was correlated with systolic blood pressure, diastolic blood pressure, interleukin (IL)-6 and tumor necrosis factor-α. Logistic regression analysis revealed that IL-6 and PVT1 were the influencing factors of gestational hypertension to pre-eclampsia transition. Moreover, prognostic analysis manifested that the incidence of fetal growth restriction in low PVT1 expression group was significantly higher than that in high PVT1 expression group. The expression level of PVT1 has a high diagnostic accuracy for gestational hypertension, and the low PVT1 expression group is more prone to fetal growth restriction.

17β-estradiol suppresses H2O2-induced senescence in human umbilical vein endothelial cells by inducing autophagy through the PVT1/miR-31/SIRT3 axis

Objective17β-estradiol (17β-E2) has been implicated in activating autophagy by upregulating SIRT3 (Sirtuin 3) expression, thereby inhibiting the senescence of vascular endothelial cells. Herein, we further examined the molecular mechanisms that regulate SIRT3 expression in 17β-E2-induced autophagy. MethodsReverse-transcription-polymerase chain reaction was employed to measure the expression of plasmacytoma variant translocation 1 (PVT1), microRNAs (miRNAs), and SIRT3, and the dual-luciferase assay was used to determine their interaction. Electron microscopy observes autophagosomes, green fluorescent protein-microtubule-associated protein 1 light chain 3 (GFP-LC3) staining, and immunoblot analysis with antibodies against LC3，beclin-1, and P62 were conducted to measure autophagy. Cellular senescence was determined using immunoblot analysis with anti-phosphorylated retinoblastoma and senescence-associated β-galactosidase staining. ResultsWomen with higher estrogen levels (during the 10–13th day of the menstrual cycle or premenopausal) exhibit markedly higher serum levels of PVT1 than women with lower estrogen levels (during the menstrual period or postmenopausal). The dual-luciferase assay showed that PVT1 acts as a sponge for miR-31, and miR-31 binds to its target gene, SIRT3. The 17β-E2 treatment increased the expression of PVT1 and SIRT3 and downregulated miR-31 expression in human umbilical vein endothelial cells (HUVECs). Consistently, PVT1 overexpression suppresses miR-31 expression, promotes 17β-E2-induced autophagy, and inhibits H2O2-induced senescence. miR-31 inhibitor increases SIRT3 expression and leads to activation of 17β-E2-induced autophagy and suppression of H2O2-induced senescence. Conclusion: Our findings demonstrated that 17β-E2 upregulates PVT1 gene expression and PVT1 functions as a sponge to inhibit miR-31, resulting in the upregulation of SIRT3 expression and activation of autophagy and subsequent inhibition of H2O2-induced senescence in HUVECs.

N6‑methyladenosine‑induced long non‑coding RNA PVT1 regulates the miR‑27b‑3p/BLM axis to promote prostate cancer progression.

Prostate cancer (PCa) is one of the most fundamental causes of cancer‑related mortality and morbidity among males. However, the underlying mechanisms have not yet been fully clarified. The present study aimed to investigate the effects of plasmacytoma variant translocation 1 (PVT1) on the malignant behaviors of PCa cells and to explore the possible molecular mechanisms involved. The expression levels of PVT1 and microRNA (miRNA/miR)‑27b‑3p in PCa tissues and cell lines were measured using reverse‑transcritpion‑quantitative polymerase chain reaction. Methyltransferase 3 (METTL3)‑mediated PVT1 N6‑methyladenosine (m6A) modifications were detected using RNA immunoprecipitation (RIP) and RNA pull‑down assays. Bioinformatics analysis was used to predict the interactions of miR‑27b‑3p with PVT1 and bloom syndrome protein (BLM), and these interactions were validated using RIP, dual‑luciferase reporter and biotin pull‑down assays. The functional importance of miR‑27b‑3p, PVT1 and BLM within PCa cells was assessed through the invitro utilization of Cell Counting Kit‑8, Transwell, wound healing and colony formation assays, and the invivo use of a mouse xenograft model. The results revealed the high expression level of PVT1 in PCa tissues and cells, and epigenetic analyses revealed the upregulation of PVT1 expression following METTL3‑mediated m6A modification. PVT1 overexpression induced PCa cells to become more proliferative, migratory and invasive, whereas PVT1 knockdown led to the opposite phenotype. Furthermore, miR‑27b‑3p was found to target both PVT1 and BLM, and PVT1 functioned to sequester miR‑27b‑3p within cells, thereby indirectly promoting the BLM expression level. BLM overexpression reversed the adverse effects of PVT1 knockdown on the migratory, proliferative and invasive capabilities of PCa cells invitro and invivo. The overexpression of PVT1 contributed to the aggressive phenotype of PCa cells by regulating the miR‑27b‑3p/BLM axis. On the whole, the findings of the present study may provide novel potential targets for the treatment of PCa.

PVT1/miR-145-5p/HK2 modulates vascular smooth muscle cells phenotype switch via glycolysis: The new perspective on the spiral artery remodeling

IntroductionVascular smooth muscle cells (VSMC) switched from a contractile phenotype to a synthetic phenotype during the decidual spiral artery (SPAs) remodeling process. The lncRNA plasmacytoma variant translocation 1 (PVT1) and glucose metabolism have been found to regulate the VSMC phenotype switch. This study aimed to analyze the dynamic expression of PVT1 and glycolytic key enzymes hexokinase2 (HK2) at different remodeling stages in early human pregnancy and elucidate the underlying mechanism of the PVT1/miR-145-5p/HK2 axis involved in the spiral artery remodeling. MethodsqRT-PCR, Western blot (WB) analysis, Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were used to detect the expression and localization of PVT1 and HK2 in decidual tissue. HA-VSMCs were transfected with specific siRNA, shRNA and plasmids to regulate corresponding genes. Extracellular lactate, cellular ATP, ROS, and intracellular NADPH levels were measured using the corresponding assay kits. Migration was measured by wound-healing and Transwell assays. Contractile phenotypic markers α-SMA, MYH11 with calponin and synthetic phenotypic markers OPN and vimentin were detected by WB. The PDC model was used to detect the degree of spiral arterial remodeling. ResultsPVT1 and HK2 were upregulated with gestational age (GA) increasing in decidual tissue during the early pregnancy. HK2 regulated the glycolytic activity and VSMC phenotype switch in vitro. PVT1 regulated the glycolytic activity and VSMC phenotype switch through HK2. PVT1 played a ceRNA role in regulating HK2 expression by sponging miR-145-5p. PVT1 and HK2 influenced spiral artery remodeling in the PDC model. DiscussionPVT1 and HK2 were upregulated, and miR-145-5p was downregulated in decidua with the GA increasing. Meanwhile, the PVT1/miR-145-5p/HK2 axis may be involved in regulating the phenotypic switch and migratory capacity of VSMCs by affecting glycolysis in decidual SPAs remodeling.

High expression of long noncoding RNA plasmacytoma variant translocation 1 is an independent risk factor for recurrence after radiofrequency ablation in atrial fibrillation patients.

Atrial fibrillation (AF) is a common arrhythmia. Radiofrequency ablation (RFA) is the major AF treatment. Long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is related to AF diagnosis. This study explored the clinical roles of PVT1 in AF. Totally, 168 AF patients and 100 healthy controls were selected. Plasma lncRNA PVT1 in AF patients before/after RFA was detected and the diagnostic efficacy and postoperative recurrence prediction value in AF were analyzed. Effects of plasma PVT1 expression on AF recurrence and its correlation with transforming growth factor beta 1 (TGF-β1) in the recurrence and non-recurrence groups were analyzed by Pearson coefficient. The risk factors of AF recurrence were evaluated. Plasma PVT1 was highly expressed in AF patients and diminished after RFA. PVT1 level >1.255 assisted AF diagnosis. The plasma PVT1 level in the recurrence group was higher than that of the non-recurrence group. PVT1 level >1.525 assisted the prediction for postoperative recurrence. AF postoperative recurrence incidence in high PVT1 expression group was clearly higher than that in low PVT1 expression group, and plasma PVT1 expression in patients of the recurrence and non-recurrence groups was positively correlated with TGF-β1 content. High PVT1 expression was an independent risk factor for postoperative recurrence. Briefly, high PVT1 level assisted AF diagnosis and recurrence evaluation after RFA and was an independent risk factor for AF postoperative recurrence.

PVT1 promotes resistance to 5-FU in colon cancer via the miR-486-5p/CDK4 axis.

Drug resistance in tumors is a major issue, limiting the curative efficacy of currently available cancer chemotherapeutics. 5-Fluorouracil (5-FU) is a commonly applied therapeutic drug in colon cancer patient regimens; however, the majority of patients develop resistance to 5-FU in the later stages of the disease, rendering this chemotherapy ineffective. Drug resistance is the main factor underlying the poor prognosis of patients with colon cancer. In recent years, a number of studies have confirmed that long non-coding (lnc)RNAs may play vital roles in tumor resistance. In the present study, the Gene Expression Omnibus (GEO) and lncRNADisease2 databases were screened for colon cancer-associated expression patterns of lncRNA plasmacytoma variant translocation 1 (PVT1). Subsequently, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect changes in PVT1 expression in resistant cell lines, and a Cell Counting Kit-8 (CCK-8) assay kit was used to assess the effects of PVT1 knockdown on the half maximal inhibitory concentrations of parental and 5-FU-resistant HCT116 cells. Subsequently, CCK-8, clone formation, and flow cytometric assays were performed to investigate the effects of PVT1 knockdown on the sensitivity of HCT116-5FU-resistant cells to 5-FU. Dual-luciferase assay, RNA pull-down and RNA immunoprecipitation assays verified the interactive regulation of PVT1, miR-486-5p and cyclin dependent kinase 4 (CDK4). PVT1 was highly expressed in HCT116-5FU-resistant cells, as compared to its expression in HCT116 parental cells. PVT1 knockdown significantly reduced the resistance of HCT116-5FU-resistant cells to 5-FU. In addition, PVT1 upregulated CDK4 expression by adsorbing miR-486-5p; however, CDK4 overexpression restored the effects of miR-486-5p inhibition on HCT116-5-FU-resistant cells. Additionally, PVT1 knockdown partially rescued CDK4 overexpression in HCT116-5-FU-resistant cells. On the whole, the findings of the present study suggest that PVT1 promotes the resistance of colon cancer cells to 5-FU by regulating the miR-486-5p/CDK4 axis. Therefore, PVT1 may prove to be a potential target for counteracting resistance to 5-FU in colon cancer therapy.

Long noncoding RNA PVT1 accelerates the growth of placental trophoblasts in preeclampsia through the microRNA‐24‐3p/HSD11B2 axis

Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) is essential for the maintenance of normal functions of trophoblasts in preeclampsia (PE).This study aims to decipher the concrete mechanism of PVT1 with the microRNA-24-3p/Type-2 11β-hydroxysteroid dehydrogenase (miR-24-3p/HSD11B2) axis in PE. PVT1, miR-24-3p, and HSD11B2 expression levels in normal placental tissues and PE placental tissues were defined. HTR-8/SVneo cells were transfected to determine the effects of PVT1, miR-24-3p, and HSD11B2 on the growth of HTR-8/SVneo cells. The relationships among PVT1/miR-24-3p/HSD11B2 in HTR-8/SVneo cells were identified. PVT1 and HSD11B2 were downregulated, while miR-24-3p was upregulated in the placenta of PE. Upregulated/downregulated PVT1 promoted/impeded the growth of human placental trophoblast (HTR-8/SVneo) cells in PE. Restored/knocked down miR-24-3p impeded/enhanced the growth of HTR-8/SVneo cells in PE. PVT1 inhibited miR-24-3p to mediate HSD11B2. PVT1 sponges miR-24-3p to regulate HSD11B2; thereby, the growth of placental trophoblasts is promoted in PE.

LncRNA PVT1 Promotes Cell Proliferation, Invasion, and Migration and Inhibits Cell Apoptosis by Phosphorylating YAP.

Gastric cancer (GC) as a serious global health problem is a threat to human longevity. Plasmacytoma variant translocation 1 (PVT1) participates in the formation and progression of various cancers, including GC. The aim of this study is to investigate the mechanism underlying the functions of PVT1 and explore a novel target for the diagnosis and treatment of GC. Analysis of the TCGA dataset using the R software identified that the lncRNA PVT1 was greatly upregulated in GC tissues. Twenty pairs of GC and adjacent normal tissues were acquired from patients with GC, and the expression of PVT1 was evaluated using RT-qPCR. Furthermore, PVT1 expression was knocked down in GC cells using siRNA, and the GC cells were divided into control, negative control (NC), and siRNA groups. Cell proliferation ability was analyzed using Cell Counting Kit-8 (CCK8) and colony formation assays, whereas cell migration and invasion ability were investigated through wound healing and Transwell assays. Moreover, Western blotting was used to analyze the expression of Yes-associated protein (YAP) and epithelial-to-mesenchymal transition (EMT) proteins. We also found that PVT1 and YAP expressions were upregulated in the GC tissues compared with those in the adjacent nontumor tissues. Knockdown of PVT1 was found to inhibit the proliferation, invasion, and migration and promote apoptosis of GC cells. Furthermore, knockdown of PVT1 downregulated YAP and promoted phosphorylation of YAP, suggesting that PVT1 exerts actions on GC cells by targeting YAP and inhibits cell apoptosis in vitro. The EMT process was also inhibited by the knockdown of PVT1. In summary, lncRNA PVT1 facilitated cell proliferation, invasion, and migration and suppressed cell apoptosis by targeting YAP. This study suggests that the expressions of PVT1 and YAP could be used for the early detection of GC and the occurrence and development of GC could be inhibited by interfering the interaction of PVT1 and YAP, which will provide new insights for the diagnosis, treatment, and prognosis of GC.

Long noncoding RNA PVT1 promotes chondrocyte extracellular matrix degradation by acting as a sponge for miR-140 in IL-1\u03b2-stimulated chondrocytes

BackgroundOsteoarthritis (OA) is a common degenerative joint disease, and chondrocyte extracellular matrix (ECM) degradation is one vital pathological feature of OA. Long noncoding RNA (lncRNA), a new kind of gene regulator, plays an important role in pathogenesis of many diseases like OA. Recent studies have confirmed that lncRNA plasmacytoma variant translocation 1 (PVT1) expression was upregulated in OA patients; however, its effect on ECM degradation remained unknown.MethodsCartilage tissue samples were obtained from 6 OA patients admitted in Guangdong Second Traditional Chinese Medicine Hospital. Chondrocytes were isolated and cultured from the collected cartilage tissue. Plasmid construction, RNA interference, cell transfection, fluorescence in situ hybridization (FISH), and pull-down assay were carried out during the research.ResultsIn this study, PVT1 expression was significantly increased in chondrocytes stimulated by interleukin-1β (IL-1β). In addition, inhibition of PVT1 significantly downregulated the increased expressions of ADAM metallopeptidase with thrombospondin type 1 motif-5 (ADAMTS-5) and matrix metalloproteinase-13 (MMP-13) induced by IL-1β. Further investigation revealed that PVT1 was an endogenous sponge RNA, which directly bound to miR-140 and inhibited miR-140 expression.ConclusionTo sum up, this study showed that PVT1 promoted expressions of ADAMTS-5 and MMP-13 as a competing endogenous RNA (ceRNA) of miR-140 in OA, which eventually led to aggravation of ECM degradation, thus providing a new and promising strategy for the treatment of OA.

LncRNA PVT1 contributes to invasion and doxorubicin resistance of bladder cancer cells through promoting MDM2 expression and AURKB-mediated p53 ubiquitination.

In most bladder cancer (BC) patients, cancer cells will eventually develop chemical resistance causing increased mortality. This study aimed to explore the mechanism of lncRNA plasmacytoma variant translocation 1 (PVT1) in regulating doxorubicin (ADM) resistance of BC cells. We observed that PVT1 expression was upregulated in ADM-resistant BC cells compared with ADM-sensitive BC cells. Downregulation of PVT1 suppressed ADM-resistant BC cell proliferation and invasion, promoted apoptosis, and increased sensitivity to ADM, while PVT1 overexpression promoted ADM-sensitive BC cell growth and their resistance to ADM. Further study uncovered that PVT1 could interact with and promote mouse double minute 2 (MDM2) expression, and upregulated MDM2-mediated Aurora kinase B (AURKB). Furthermore, Nutlin-3, an inhibitor of MDM2, could counteract the promotive effects of PVT1 overexpression on ADM resistance of ADM-sensitive BC cell, the expression of multidrug-resistance-related proteins, and the inhibition of p53-mediated tumor suppressor genes. And, overexpression of MDM2 or AURKB reversed the promotive effects of PVT1 silence on the ADM sensitivity of ADM-resistant BC cell, and the inhibitory effect on expression multidrug resistance proteins. Mechanically, AURKB increased MDM2-mediated p53 ubiquitination. Taken together, PVT1 promoted BC cell proliferation and drug resistance via elevating MDM2 expression and AURKB-mediated p53 ubiquitination.

Up-regulated lncRNA-PVT1 expression in peripheral blood mononuclear cells of patients with coronary artery disease is correlated with decreased interleukin-10 production.

Plasmacytoma variant translocation 1 (PVT1) is a newly discovered long non-coding RNA, which has not been previously studied in the inflammatory responses of the peripheral blood mononuclear cells (PBMCs) of patients with coronary artery disease (CAD). This cross-sectional study was conducted on 15 CAD patients and 15 non-CAD (NCAD) individuals. The PVT1 expression was assessed in the PBMCs of the participants using a real-time polymerase chain reaction. Interleukin (IL)-10, IL-22, and matrix metalloproteinase-9 (MMP-9) were measured in the plasma and supernatant of cultured PBMCs in the presence or absence of lipopolysaccharide (LPS) using flow cytometry and enzyme-linked immunosorbent assay. An increased expression of PVT1 was observed in the untreated PBMCs of CAD patients, compared to the NCAD group. The PVT1 was significantly up-regulated after LPS treatment in the PBMCs of both groups. Plasma MMP-9 levels were found to be higher in CAD patients than in the control individuals. The level of IL-10 and IL-22 production by the non-treated PBMCs of CAD cases was significantly lower than the NCAD group. Overall, in the examined population, PVT1 expression was negatively correlated with IL-10 secretion. Moreover, the results showed a significant negative correlation between PVT1 expression and IL-10 production by untreated cells. The PVT1 expression augmented in the PBMCs of CAD patients, which could be associated with the decreased IL-10 generation by the PBMCs of these patients.