Linear and circular PVT1 in hematological malignancies and immune response: two faces of the same coin

Role of lncRNA PVT1 in the progression of urological cancers: Novel insights into signaling pathways and clinical opportunities

Urologic malignancies, encompassing cancers of the kidney, bladder, and prostate, represent approximately 25 % of all cancer cases. Recent advances have enhanced our understanding of PVT1's crucial functions. Long noncoding RNAs influence both the onset and development of cancer, as well as epigenetic alterations. Recent findings have focused on PVT1's mechanism of action across several malignancies, particularly urologic cancers. Understanding the various functions of PVT1 linked to cancer is necessary for the development of cancer detection and treatment when PVT1 is dysregulated. Furthermore, recent advancements in genomic and epigenetic research have elucidated the complex regulatory networks that control PVT1 expression. Comprehending the intricate role of PVT1 Understanding the complex function of PVT1 in urologic cancers has substantial clinical implications. Here, we summarize some of the most recent findings about the carcinogenic effects of PVT1 signaling pathways and the possible treatment strategies for urological malignancies that target these pathways.

Regulation of immune-mediated chemoresistance in cancer by lncRNAs: an in-depth review of signaling pathways

Resistance to cancer therapies is increasingly recognized as being influenced by long non-coding RNAs (lncRNAs), which are pivotal in regulating cellular functions and gene expression. Elucidating the intricate relationship between lncRNAs and the mechanisms underlying drug resistance is critical for advancing effective therapeutic strategies. This study offers an in-depth review of the regulatory roles lncRNAs play in various signaling and immunological pathways implicated in cancer chemoresistance. lncRNA-mediated influence on drug resistance-related signaling pathways will be presented, including immune evasion mechanisms and other essential signaling cascades. Furthermore, the interplay between lncRNAs and the immune landscape will be dissected, illustrating their substantial impact on the development of chemoresistance. Overall, the potential of lncRNA-mediated signaling networks as a therapeutic strategy to combat cancer resistance has been highlighted. This review reiterates the fundamental role of lncRNAs in chemoresistance and proposes promising avenues for future research and the development of targeted therapeutic interventions.

CircPVT1 weakens miR-33a-5p unleashing the c-MYC/GLS1 metabolic axis in breast cancer

BACKGROUND

Altered metabolism is one of the cancer hallmarks. The role of circRNAs in cancer metabolism is poorly studied. Specifically, the impact of circPVT1, a well-known oncogenic circRNA on triple negative breast cancer metabolism is mechanistically underexplored.

METHODS

The clinical significance of circPVT1 expression levels was assessed in human breast cancer samples using digital PCR and the cancer genome atlas (TCGA) dataset. The oncogenic activity of circPVT1 was assessed in TNBC cell lines and in MCF-10 A breast cell line by either ectopic expression or depletion of circPVT1 molecule. CircPVT1 mediated metabolic perturbation was assessed by 1 H-NMR spectroscopy metabolic profiling. The binding of circPVT1 to miR-33a-5p and c-Myc recruitment onto the Glutaminase gene promoter were assessed by RNA immunoprecipitation and chromatin immunoprecipitation assays, respectively. The circPVT1/miR-33a-5p/Myc/GLS1 axis was functionally validated in breast cancer patients derived organoids. The viability of 2D and PDO cell models was assessed by ATP light assay and Opera Phenix plus high content screening.

RESULTS

We initially found that the expression of circPVT1 was significantly higher in tumoral tissues than in non-tumoral breast tissues. Basal like breast cancer patients with higher levels of circPVT1 exhibited shorter disease-free survival compared to those with lower expression. CircPVT1 ectopic expression rendered fully transformed MCF-10 A immortalized breast cells and increased tumorigenicity of TNBC cell lines. Depletion of endogenous circPVT1 reduced tumorigenicity of SUM-159PT and MDA-MB-468 cells. 1 H-NMR spectroscopy metabolic profiling of circPVT1 depleted breast cancer cell lines revealed reduced glycolysis and glutaminolitic fluxes. Conversely, MCF-10 A cells stably overexpressing circPVT1 exhibited increased glutaminolysis. Mechanistically, circPVT1 sponges miR-33a-5p, a well know metabolic microRNA, which in turn releases c-MYC activity promoting transcriptionally glutaminase. This activity facilitates the conversion of glutamine to glutamate. CircPVT1 depletion synergizes with GLS1 inhibitors BPTES or CB839 to reduce cell viability of breast cancer cell lines and breast cancer-derived organoids.

CONCLUSIONS

In aggregate, our findings unveil the circPVT1/miR-33a-5p/Myc/GLS1 axis as a pro-tumorigenic metabolic event sustaining breast cancer transformation with potential therapeutic implications.

Role of circular RNAs in cancer therapy resistance

Over the past decade, circular RNAs (circRNAs) have gained recognition as a novel class of genetic molecules, many of which are implicated in cancer pathogenesis via different mechanisms, including drug resistance, immune escape, and radio-resistance. ExosomalcircRNAs, in particular, facilitatecommunication between tumour cells and micro-environmental cells, including immune cells, fibroblasts, and other components. Notably, micro-environmental cells can reportedly influence tumour progression and treatment resistance by releasing exosomalcircRNAs. circRNAs often exhibit tissue- and cancer-specific expression patterns, and growing evidence highlights their potential clinical relevance and utility. These molecules show strong promise as potential biomarkers and therapeutic targets for cancer diagnosis and treatment. Therefore, this review aimed to briefly discuss the latest findings on the roles and resistance mechanisms of key circRNAs in the treatment of various malignancies, including lung, breast, liver, colorectal, and gastric cancers, as well as haematological malignancies and neuroblastoma.This review will contribute to the identification of new circRNA biomarkers for the early diagnosis as well as therapeutic targets for the treatment of cancer.

Synergistic RAS-MAPK and AKT Activation in MYC-Driven Tumors via Adjacent PVT1 Rearrangements

MYC-driven (MYC+) cancers are aggressive and often fatal. MYC dysregulation is a key event in these cancers, but overexpression of MYC alone is not always enough to cause cancer. Plasmocytoma Variant Translocation 1 (PVT1), a long non-coding RNA (lncRNA) adjacent to MYC on chromosome 8 is a rearrangement hotspot in many MYC+ cancers. In addition to being co-amplified with MYC, the genomic rearrangement at PVT1 involves translocation, which has had obscure functional consequences. We report that translocation at the PVT1 locus cause asymmetric enrichment of 5'-PVT1 and loss of 3'-PVT1. Despite being classified as a non-coding RNA, the retained 5' region of PVT1 generates a circular RNA (CircPVT1) that codes for the novel peptide we call Firefox (FFX). FFX augments AKT signaling and synergistically activates MYC and mTORC1 in these cells. Further, the 3' end of PVT1, which is lost during the translocation, codes for a tumor-suppressing micropeptide we named as Honeybadger (HNB). We demonstrate that HNB interacts with KRAS and disrupts the activation of KRAS effectors. Loss of HNB leads to activation of RAS/MAPK signaling pathway, and enhances MYC stability by promoting phosphorylation of MYC at Ser62. These findings identify PVT1 as a critical node that synchronizes MYC, AKT, and RAS-MAPK activities in cancer. Our study thus identifies a key mechanism by which rearrangements at the PVT1 locus activate additional oncogenic pathways that synergize with MYC to exacerbate the aggressiveness of MYC+ cancers. This newfound understanding explains the poor prognosis associated with MYC+ cancers and offers potential therapeutic targets that could be leveraged in treatment strategies for these cancers.

Super-enhancer-associated circPVT1 promotes malignancy of hepatocellular carcinoma via YBX1-mediated RRM2 activation

Circular RNAs (circRNAs), the essential members of epigenetic reprogramming, are emerging as an appealing layer in hepatocellular carcinoma (HCC). Super-enhancers (SEs) are large clusters of transcriptional enhancers with the tremendous gene activation potential and are extensively investigated in cancer research. The present study explores and uncovers an SE-related circRNA circPVT1, identifying its biological functions and downstream mechanisms in HCC. CircPVT1 is upregulated in HCC, serving as an independent prognostic factor for patients with HCC. Enrichment of H3K27ac and H3K4me1 modifications has been confirmed at the genomic loci of circPVT1's host gene, and the expression of circPVT1 is triggered by SEs. Functionally, circPVT1 enhances cell propagation and mobility capabilities in vitro, and facilitates tumour growth and metastasis in vivo. Mechanistically, circPVT1 recruits YBX1 into the cell nucleus, promoting the transcription of RRM2. Dysregulation of the circPVT1-RRM2 axis advances HCC malignancy, while inhibition of RRM2 or SE alleviates the effects of circPVT1 overexpression. In conclusion, our work demonstrates that circPVT1 is driven by super-enhancers. CircPVT1 promotes HCC progression via YBX1-mediated transcriptional activation of RRM2. These findings provide constructive insights into exploring the pathogenesis of HCC.

Exosome-mediated transfer of lncRNA RP3-340B19.3 promotes the progression of breast cancer by sponging miR-4510/MORC4 axis

BACKGROUND

This study aims to explore the molecular mechanism of lncRNA RP3-340B19.3 on breast cancer cell proliferation and metastasis and clinical significance of lncRNA RP3-340B19.3 for breast cancer.

METHODS

The subcellular localization of lncRNA RP3-340B19.3 was identified using RNA fluorescence in situ hybridization (FISH). The expression of lncRNA RP3-340B19.3 in breast cancer cells, breast cancer tissues, as well as the serum and serum exosomes of breast cancer patients, was measured through quantitative RT-PCR. In the in vitro setting, we conducted experiments to observe the effects of RP3-340B19.3 on both cell migration and proliferation. This was achieved through the utilization of transwell migration assays as well as clone formation assays. Meanwhile, transwell migration assays and clone formation assays were used to observe the effects of MDA-MB-231-exosomes enriched in RP3-340B19.3 on breast cancer microenvironment cells MCF7 and BMMSCs. Additionally, western blotting techniques were used to assess the expression levels of proteins associated with essential cellular processes such as proliferation, apoptosis, and metastasis. In vivo, the impact of RP3-340B19.3 knockdown on tumour weight and volume was observed within a nude mice model. We aimed to delve into the intricate molecular mechanisms involving RP3-340B19.3 by using bioinformatics analysis, dual luciferase reporter gene experiments and western blotting. Moreover, the potential correlations between RP3-340B19.3 expression and various clinical pathological characteristics were analyzed.

RESULTS

Our investigation revealed that RP3-340B19.3 was expressed in both the cytoplasm and nucleus, with a noteworthy increase in breast cancer cells. Notably, we found that RP3-340B19.3 exerted a promoting influence on the proliferation and migration of breast cancer cells, both in vitro and in vivo. MDA-MB-231-exosomes enriched in RP3-340B19.3 promoted the proliferation and migration of MCF7 and BMMSCs in vitro. Mechanistically, RP3-340B19.3 demonstrated the capability to modulate the expression of MORC4 by forming a complex with miR-4510. This interaction subsequently triggered the activation of the NF-κB and Wnt-β-catenin signaling pathways. Furthermore, our study highlighted the potential diagnostic utility of RP3-340B19.3. We discovered its presence in the serum and exosomes of breast cancer patients, showing promising efficacy as a diagnostic marker. Notably, the diagnostic potential of RP3-340B19.3 was particularly significant in relation to distinguishing between different pathological types of breast cancer and correlating with tumour diameter.

CONCLUSION

Our findings establish that RP3-340B19.3 plays a pivotal role in driving the proliferation and metastasis of breast cancer. Additionally, exosomes enriched in RP3-340B19.3 could influence MCF7 and BMMSCs in tumour microenvironment, promoting the progression of breast cancer. This discovery positions RP3-340B19.3 as a prospective novel candidate for a tumour marker, offering substantial potential in the realms of breast cancer diagnosis and treatment strategies.

The relationship of peripheral blood lncRNA-PVT1 and miR-146a levels with Th17/Treg cytokines in patients with Hashimoto's thyroiditis and their clinical significance

Hashimoto's thyroiditis (HT) is a prevalent autoimmune disease. We investigated the relationship of peripheral blood long noncoding RNA-plasmacytoma variant translocation 1 (lncRNA-PVT1) and microRNA (miR)-146a levels with Th17/Treg-related cytokines in HT patients and their clinical significance. Correlations of PVT1 and miR-146a with Th17/Treg-related cytokines were analyzed, and its clinical value in diagnosing HT was assessed. Results showed reduced lncRNA-PVT1 and interleukin (IL)-10 levels and increased miR-146a and IL-17 levels in HT patients. lncRNA-PVT1 negatively interrelated with miR-146a, IL-17, IL-23 and IL-6, and positively interrelated with IL-10; miR-146a positively correlated with IL-17, IL-23 and IL-6, but negatively correlated with IL-10 in HT patients. The area under the curve (AUC) of lncRNA-PVT1 and miR-146a levels for diagnosing HT were 0.822 and 0.844, respectively (sensitivity 88.73% and 86.62%, specificity 67.02% and 69.15%, cut-off values 0.76 and 2.73), with their combined detections yielding a higher AUC. Patients with poorly expressed lncRNA-PVT1 and highly expressed miR-146a had elevated HT incidence. lncRNA-PVT1 and miR-146a levels were also found to be an independent influencing factor for HT occurrence. Our findings suggest that HT patients have low peripheral blood lncRNA-PVT1 expression and high miR-146a expression. lncRNA-PVT1 and miR-146a level changes were correlated with Th17/Treg cytokine imbalance and could be a potential diagnostic tool and independent influencing factor for HT.

Circular RNA as a Biomarker for Diagnosis, Prognosis and Therapeutic Target in Acute and Chronic Lymphoid Leukemia

Circular RNAs (circRNAs) are single-stranded RNAs that have received much attention in recent years. CircRNAs lack a 5' head and a 3' poly-A tail. The structure of this type of RNAs make them resistant to digestion by exonucleases. CircRNAs are expressed in different cells and have various functions. The function of circRNAs is done by sponging miRNAs, changing gene expression, and protein production. The expression of circRNAs changes in different types of cancers, which causes changes in cell growth, proliferation, differentiation, and apoptosis. Changes in the expression of circRNAs can cause the invasion and progression of tumors. Studies have shown that changes in the expression of circRNAs can be seen in acute lymphoid leukemia (ALL) and chronic lymphoid leukemia (CLL). The conducted studies aim to identify circRNAs whose expression has changed in these leukemias and their more precise function so that these circRNAs can be identified as biomarkers, prediction of patient prognosis, and treatment targets for ALL and CLL patients. In this study, we review the studies conducted on the role and function of circRNAs in ALL and CLL patients. The results of the studies show that there is a possibility of using circRNAs as biomarkers in the identification and treatment of patients in the future.

Carvacrol inhibits the progression of oral submucous fibrosis via downregulation of PVT1/miR-20a-5p-mediated pyroptosis

Oral submucous fibrosis (OSF) is a precancerous condition in the oral cavity, which is closely related to the myofibroblast conversion of buccal mucosal fibroblasts (BMFs) after chronic consumption of areca nut. Emerging evidence suggests pyroptosis, a form of programmed cell death that is mediated by inflammasome, is implicated in persistent myofibroblast activation and fibrosis. Besides, numerous studies have demonstrated the effects of non-coding RNAs on pyroptosis and myofibroblast activities. Herein, we aimed to target key long non-coding RNA PVT1 with natural compound, carvacrol, to alleviate pyroptosis and myofibroblast activation in OSF. We first identified PVT1 was downregulated in the carvacrol-treated fBMFs and then demonstrated that myofibroblast features and expression of pyroptosis makers were all reduced in response to carvacrol treatment. Subsequently, we analysed the expression of PVT1 and found that PVT1 was aberrantly upregulated in OSF specimens and positively correlated with several fibrosis markers. After revealing the suppressive effects of carvacrol on myofibroblast characterisitcs and pyroptosis were mediated by repression of PVT1, we then explored the potential mechanisms. Our data showed that PVT1 may serve as a sponge of microRNA(miR)-20a to mitigate the myofibroblast activation and pyroptosis. Altogether, these findings indicated that the anti-fibrosis effects of carvacrol merit consideration and may be due to the attenuation of pyroptosis and myofibroblast activation by targeting the PVT1/miR-20a axis.

[Molecular Mechanism of circVRK1 Regulating the Proliferation and Apoptosis of Acute Lymphoblastic Leukemia KOCL44 Cells by Targeting miR-4428]

Objective

To elucidate the role of circVRK1 and its interaction with miR-4428 in regulating proliferation and apoptosis in acute lymphoblastic leukemia (ALL) cells.

Methods

KOCL44 ALL cells were cultured in vitro, and experimental groups included pcDNA, pcDNA-circVRK1, anti-miR-NC, anti-miR-4428, si-NC, si-circVRK1, pcDNA-circVRK1+miR-NC, and pcDNA-circVRK1+miR-4428. The expression levels of circVRK1 and miR-4428 were detected using qRT-PCR. CCK-8 assays and flow cytometry were used to assess cell proliferation and apoptosis, respectively. The dual luciferase reporter assays were employed to investigate the interaction between circVRK1 and miR-4428, with groups categorized as WT-circVRK1+miR-NC, WT-circVRK1+miR-4428, MUT-circVRK1+miR-NC, and MUT-circVRK1+ miR-4428. Western blotting was utilized to detect the expression levels of Ki-67, cleaved caspase-3, and cleaved caspase-9 proteins.

Results

Compared to the pcDNA group, circVRK1 expression was up-regulated in the pcDNA-circVRK1 group (P<0.05). Compared to transfection with pcDNA or anti-miR-NC, transfection with pcDNA-circVRK1 or anti-miR-4428 led to decreased cell viability and Ki-67 protein levels in KOCL44 cells (P<0.05), and increased apoptosis rates and levels of cleaved caspase-3 and cleaved caspase-9 (P<0.05). circVRK1 was found to negatively regulate miR-4428 expression, with this effect observed only in the WT-circVRK1 group. miR-4428 levels were lower in the pcDNA-circVRK1 group compared to the pcDNA group (P<0.05) and higher in the si-circVRK1 group compared to the si-NC group (P<0.05). Co-transfection with pcDNA-circVRK1+miR-4428 resulted in increased cell viability (P<0.05) and Ki-67 expression (P<0.05), and decreased apoptosis rates and levels of cleaved caspase-3 and cleaved caspase-9 (P<0.05) compared to co-transfection with pcDNA-circVRK1+miR-NC.

Conclusion

Overexpression of circVRK1 reduces the proliferation ability of acute ALL cells and induces cell apoptosis by downregulating miR-4428 expression.

Cancer fusion transcripts with human non-coding RNAs

Cancer chimeric, or fusion, transcripts are thought to most frequently appear due to chromosomal aberrations that combine moieties of unrelated normal genes. When being expressed, this results in chimeric RNAs having upstream and downstream parts relatively to the breakpoint position for the 5'- and 3'-fusion components, respectively. As many other types of cancer mutations, fusion genes can be of either driver or passenger type. The driver fusions may have pivotal roles in malignisation by regulating survival, growth, and proliferation of tumor cells, whereas the passenger fusions most likely have no specific function in cancer. The majority of research on fusion gene formation events is concentrated on identifying fusion proteins through chimeric transcripts. However, contemporary studies evidence that fusion events involving non-coding RNA (ncRNA) genes may also have strong oncogenic potential. In this review we highlight most frequent classes of ncRNAs fusions and summarize current understanding of their functional roles. In many cases, cancer ncRNA fusion can result in altered concentration of the non-coding RNA itself, or it can promote protein expression from the protein-coding fusion moiety. Differential splicing, in turn, can enrich the repertoire of cancer chimeric transcripts, e.g. as observed for the fusions of circular RNAs and long non-coding RNAs. These and other ncRNA fusions are being increasingly recognized as cancer biomarkers and even potential therapeutic targets. Finally, we discuss the use of ncRNA fusion genes in the context of cancer detection and therapy.

The regulatory role and clinical application prospects of circRNA in the occurrence and development of CNS tumors

BACKGROUND

Central nervous system (CNS) tumors originate from the spinal cord or brain. The study showed that even with aggressive treatment, malignant CNS tumors have high mortality rates. However, CNS tumor risk factors and molecular mechanisms have not been verified. Due to the reasons mentioned above, diagnosis and treatment of CNS tumors in clinical practice are currently fraught with difficulties. Circular RNAs (circRNAs), single-stranded ncRNAs with covalently closed continuous structures, are essential to CNS tumor development. Growing evidence has proved the numeral critical biological functions of circRNAs for disease progression: sponging to miRNAs, regulating gene transcription and splicing, interacting with proteins, encoding proteins/peptides, and expressing in exosomes.

AIMS

This review aims to summarize current progress regarding the molecular mechanism of circRNA in CNS tumors and to explore the possibilities of clinical application based on circRNA in CNS tumors.

METHODS

We have summarized studies of circRNA in CNS tumors in Pubmed.

RESULTS

This review summarized their connection with CNS tumors and their functions, biogenesis, and biological properties. Furthermore, we introduced current advances in clinical RNA-related technologies. Then we discussed the diagnostic and therapeutic potential (especially for immunotherapy, chemotherapy, and radiotherapy) of circRNA in CNS tumors in the context of the recent advanced research and application of RNA in clinics.

CONCLUSIONS

CircRNA are increasingly proven to participate in decveloping CNS tumors. An in-depth study of the causal mechanisms of circRNAs in CNS tomor progression will ultimately advance their implementation in the clinic and developing new strategies for preventing and treating CNS tumors.

Functional relevance of circRNA aberrant expression in pediatric acute leukemia with KMT2A::AFF1 fusion

ABSTRACT

Circular RNAs (circRNAs) are emerging molecular players in leukemogenesis and promising therapeutic targets. In KMT2A::AFF1 (MLL::AF4)-rearranged leukemia, an aggressive disease compared with other pediatric B-cell precursor (BCP) acute lymphoblastic leukemia (ALL), data about circRNAs are limited. Here, we disclose the circRNA landscape of infant patients with KMT2A::AFF1 translocated BCP-ALL showing dysregulated, mostly ectopically expressed, circRNAs in leukemia cells. Most of these circRNAs, apart from circHIPK3 and circZNF609, previously associated with oncogenic behavior in ALL, are still uncharacterized. An in vitro loss-of-function screening identified an oncogenic role of circFKBP5, circKLHL2, circNR3C1, and circPAN3 in KMT2A::AFF1 ALL, whose silencing affected cell proliferation and apoptosis. Further study in an extended cohort disclosed a significantly correlated expression of these oncogenic circRNAs and their putative involvement in common regulatory networks. Moreover, it showed that circAFF1 upregulation occurs in a subset of cases with HOXA KMT2A::AFF1 ALL. Collectively, functional analyses and patient data reveal oncogenic circRNA upregulation as a relevant mechanism that sustains the malignant cell phenotype in KMT2A::AFF1 ALL.

A genome-wide association study on hematopoietic stem cell transplantation reveals novel genomic loci associated with transplant outcomes

Introduction

Data on genomic susceptibility for adverse outcomes after hematopoietic stem cell transplantation (HSCT) for recipients are scarce.

Methods

We performed a genome wide association study (GWAS) to identify genes associated with survival/mortality, relapse, and severe graft-versus-host disease (sGvHD), fitting proportional hazard and subdistributional models to data of n=1,392 recipients of European ancestry from three centres.

Results

The single nucleotide polymorphism (SNP) rs17154454, intronic to the neuronal growth guidant semaphorin 3C gene (SEMA3C), was genome-wide significantly associated with event-free survival (p=7.0x10-8) and sGvHD (p=7.5x10-8). Further associations were detected for SNPs in the Paxillin gene (PXN) with death without prior relapse or sGvHD, as well as for SNPs of the Plasmacytoma Variant Translocation 1 gene (PVT1, a long non-coding RNA gene), the Melanocortin 5 Receptor (MC5R) gene and the WW Domain Containing Oxidoreductase gene (WWOX), all associated with the occurrence of sGvHD. Functional considerations support the observed associations.

Discussion

Thus, new genes were identified, potentially influencing the outcome of HSCT.

Proliferation-promoting roles of linear and circular PVT1 are independent of their ability to bind miRNAs in B-cell lymphoma

Plasmacytoma Variant Translocation 1 (PVT1) is a long non-coding RNA located at 8q24.21 immediately downstream of MYC. Both the linear and circular PVT1 transcripts contribute to cancer pathogenesis by binding microRNAs. However, little is known about their roles in B-cell lymphoma. Here we studied their expression patterns, role in growth, and ability to bind miRNAs in B-cell lymphoma. Linear PVT1 transcripts were downregulated in B-cell cell lymphoma lines compared to germinal center B cells, while circPVT1 levels were increased. Two Hodgkin lymphoma cell lines had a homozygous deletion including the 5' region of the PVT1 locus, resulting in a complete lack of circPVT1 and 5' linear PVT1 transcripts. Inhibition of both linear and circular PVT1 decreased growth of Burkitt lymphoma, while the effects on Hodgkin lymphoma and diffuse large B cell lymphoma were less pronounced. Overexpression of circPVT1 promoted growth of B-cell lymphoma lacking or having low endogenous circPVT1 levels. Contrary to other types of cancer, linear and circular PVT1 transcripts did not interact with miRNAs in B-cell lymphoma. Overall, we showed an opposite expression pattern of linear and circular PVT1 in B-cell lymphoma. Their effect on growth was independent of their ability to bind miRNAs.

Transcriptional repression of lncRNA and miRNA subsets mediated by LRF during erythropoiesis

Non-coding RNA (ncRNA) species, mainly long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been currently imputed for lesser or greater involvement in human erythropoiesis. These RNA subsets operate within a complex circuit with other epigenetic components and transcription factors (TF) affecting chromatin remodeling during cell differentiation. Lymphoma/leukemia-related (LRF) TF exerts higher occupancy on DNA CpG rich sites and is implicated in several differentiation cell pathways and erythropoiesis among them and also directs the epigenetic regulation of hemoglobin transversion from fetal (HbF) to adult (HbA) form by intervening in the γ-globin gene repression. We intended to investigate LRF activity in the evolving landscape of cells' commitment to the erythroid lineage and specifically during HbF to HbA transversion, to qualify this TF as potential repressor of lncRNAs and miRNAs. Transgenic human erythroleukemia cells, overexpressing LRF and further induced to erythropoiesis, were subjected to expression analysis in high LRF occupancy genetic loci-producing lncRNAs. LRF abundance in genetic loci transcribing for studied lncRNAs was determined by ChIP-Seq data analysis. qPCRs were performed to examine lncRNA expression status. Differentially expressed miRNA pre- and post-erythropoiesis induction were assessed by next-generation sequencing (NGS), and their promoter regions were charted. Expression levels of lncRNAs were correlated with DNA methylation status of flanked CpG islands, and contingent co-regulation of hosted miRNAs was considered. LRF-binding sites were overrepresented in LRF overexpressing cell clones during erythropoiesis induction and exerted a significant suppressive effect towards lncRNAs and miRNA collections. Based on present data interpretation, LRF's multiplied binding capacity across genome is suggested to be transient and associated with higher levels of DNA methylation. KEY MESSAGES: During erythropoiesis, LRF displays extensive occupancy across genetic loci. LRF significantly represses subsets of lncRNAs and miRNAs during erythropoiesis. Promoter region CpG islands' methylation levels affect lncRNA expression. MiRNAs embedded within lncRNA loci show differential regulation of expression.

Uncovering the expression of circPVT1 in the extracellular vesicles of acute myeloid leukemia patients

Extracellular vesicles (EVs) act as molecular mediators in the tumor microenvironment, by shuttling information contained within malignant cells and functioning as regulators of the immune system. Circular (circ)RNAs are characterized by a closed loop-like structure that makes them more stable in the extracellular milieu and suitable to be packaged inside EVs. circPVT1 (hsa_circ_0001821) showed an oncogenic role in several cancer types and immunosuppressive properties in myeloid and lymphoid cell subsets. In this study, we characterized EVs from acute myeloid leukemia (AML) patients in terms of size, concentrations, surface markers and circPVT1 cargo. We showed that circPVT1 is overexpressed by primary blast cells from newly-diagnosed AML patients compared with hematopoietic stem-progenitor cells and is released as cell-free RNA in the plasma. We isolated EVs from the plasma of AML patients and healthy subjects by size exclusion chromatography and characterized them by nanoparticle tracking analysis. EVs from patients' plasma are larger compared with those from healthy subjects and their surface profile is characterized by higher levels of the leukemic cell markers CD133, CD105, CD49e and other immune-related epitopes, with differences according to AML molecular profile. Moreover, digital PCR analysis revealed that circPVT1 is more abundant inside EVs from the plasma of AML patients compared with healthy subjects. Our findings provide new insights on the features and content of AML EVs and suggest a role of circPVT1 in the crosstalk between AML cells and the tumor microenvironment.

Deoxynivalenol upregulates hypoxia-inducible factor-1α to promote an "immune evasion" process by activating STAT3 signaling

Trichothecene mycotoxin deoxynivalenol (DON) negatively regulates immune response by damaging host immune system and harming the organism's health. We hypothesized that DON can initiate an active immunosuppressive mechanism similar to "immune evasion" to alter the cellular microenvironment and evade immune surveillance. We tested this hypothesis using the RAW264.7 macrophage model. DON rapidly increased the expression of immune checkpoints PD-1 and PD-L1, inflammatory cytokine TGF-β, and key immune evasion factors STAT3, VEGF, and TLR-4, and caused cellular hypoxia. Importantly, hypoxia-inducible factor-1α (HIF-1α) acts as a key regulator of DON-induced immunosuppression. HIF-1α accumulated in the cytoplasm and was gradually transferred to the nucleus following DON treatment. Moreover, DON activated HIF-1α through STAT3 signaling to upregulate downstream signaling, including PD-1/PD-L1. Under DON treatment, immunosuppressive miR-210-3p, lncRNA PVT1, lncRNA H19, and lncRNA HOTAIR were upregulated by the STAT3/HIF-1α axis. Moreover, DON damaged mitochondrial function, causing mitophagy, and suppressed immune defenses. Collectively, DON triggered RAW264.7 intracellular hypoxia and rapidly activated HIF-1α via STAT3 signaling, activating immune evasion signals, miRNAs, and lncRNAs, thereby initiating the key link of immune evasion. This study offers further clues for accurate prevention and treatment of immune diseases caused by mycotoxins.

The new world of RNA diagnostics and therapeutics

The 5th Workshop IRE on Translational Oncology was held in Rome (Italy) on 27-28 March at the IRCCS Regina Elena National Cancer Institute. This meeting entitled "The New World of RNA diagnostics and therapeutics" highlightes the significant progress in the RNA field made over the last years. Research moved from pure discovery towards the development of diagnostic biomarkers or RNA-base targeted therapies seeking validation in several clinical trials. Non-coding RNAs in particular have been the focus of this workshop due to their unique properties that make them attractive tools for the diagnosis and therapy of cancer.This report collected the presentations of many scientists from different institutions that discussed recent oncology research providing an excellent overview and representative examples for each possible application of RNA as biomarker, for therapy or to increase the number of patients that can benefit from precision oncology treatment.In particular, the meeting specifically emphasized two key features of RNA applications: RNA diagnostic (Blandino, Palcau, Sestito, Díaz Méndez, Cappelletto, Pulito, Monteonofrio, Calin, Sozzi, Cheong) and RNA therapeutics (Dinami, Marcia, Anastasiadou, Ryan, Fattore, Regazzo, Loria, Aharonov).

Understanding the lncRNA/miRNA-NFκB regulatory network in Diabetes Mellitus: From function to clinical translation

Diabetes mellitus (DM) and its significant ramifications make out one of the primary reasons behind morbidity worldwide. Noncoding RNAs (ncRNAs), such as microRNAs and long noncoding RNAs, are involved in regulating manifold biological processes, including diabetes initiation and progression. One of the established pathways attributed to DM development is NF-κB signaling. Neurons, β cells, adipocytes, and hepatocytes are among the metabolic tissues where NF-κB is known to produce a range of inflammatory chemokines and cytokines. The direct or indirect role of ncRNAs such as lncRNAs and miRNAs on the NF-κB signaling pathway and DM development has been supported by many studies. As a result, effective diabetes treatment and preventive methods will benefit from a comprehensive examination of the interplay between NF-κB and ncRNAs. Herein, we provide a concise overview of the role of NF-κB-mediated signaling pathways in diabetes mellitus and its consequences. The reciprocal regulation of ncRNAs and the NF-κB signaling pathway in diabetes is then discussed, shedding light on the pathogenesis of the illness and its possible therapeutic interventions.

Regulatory factors involved in Th17/Treg cell balance of immune thrombocytopenia

Immune thrombocytopenia is a common heterogeneous autoimmune disease that is characterized by decreasing peripheral blood platelet counts and increasing risk of bleeding. Studies have shown that an imbalance between T helper 17 (Th17) and Regulatory T (Treg) cells differentiated from CD4+T-cells is a key factor influencing the development and pathogenesis of immune thrombocytopenia. Th17 cells promote the development of chronic inflammatory disorders and induce autoimmune diseases, whereas Treg cells regulate immune homeostasis and prevent autoimmune diseases. Several regulators affecting the production and maintenance of these cells are also essential for proper regulation of Th17/Treg balance; these regulatory factors include cell surface proteins, miRNAs, and cytokine signaling. In this review, we focus on the function and role of balance between Th17 and Treg cells in immune thrombocytopenia, the regulatory factors, and therapeutic goals of this balance in immune thrombocytopenia.

HERV-K (HML-2) insertion polymorphisms in the 8q24.13 region and their potential etiological associations with acute myeloid leukemia

Human endogenous retroviruses (HERVs) are LTR retrotransposons that are present in the human genome. Among them, members of the HERV-K (HML-2) group are suspected to play a role in the development of different types of cancer, including lung, ovarian, and prostate cancer, as well as leukemia. Acute myeloid leukemia (AML) is an important disease that causes 1% of cancer deaths in the United States and has a survival rate of 28.7%. Here, we describe a method for assessing the statistical association between HERV-K (HML-2) transposable element insertion polymorphisms (or TIPs) and AML, using whole-genome sequencing and read mapping using TIP_finder software. Our results suggest that 101 polymorphisms involving HERV-K (HML-2) elements were correlated with AML, with a percentage between 44.4 to 56.6%, most of which (70) were located in the region from 8q24.13 to 8q24.21. Moreover, it was found that the TRIB1, LRATD2, POU5F1B, MYC, PCAT1, PVT1, and CCDC26 genes could be displaced or fragmented by TIPs. Furthermore, a general method was devised to facilitate analysis of the correlation between transposable element insertions and specific diseases. Finally, although the relationship between HERV-K (HML-2) TIPs and AML remains unclear, the data reported in this study indicate a statistical correlation, as supported by the χ² test with p-values < 0.05.

The function and mechanisms of action of circular RNAs in Urologic Cancer

Kidney, bladder, and prostate cancer are the three major tumor types of the urologic system that seriously threaten human health. Circular RNAs (CircRNAs), special non-coding RNAs with a stabile structure and a unique back-splicing loop-forming ability, have received recent scientific attention. CircRNAs are widely distributed within the body, with important biologic functions such as sponges for microRNAs, as RNA binding proteins, and as templates for regulation of transcription and protein translation. The abnormal expression of circRNAs in vivo is significantly associated with the development of urologic tumors. CircRNAs have now emerged as potential biomarkers for the diagnosis and prognosis of urologic tumors, as well as targets for the development of new therapies. Although we have gained a better understanding of circRNA, there are still many questions to be answered. In this review, we summarize the properties of circRNAs and detail their function, focusing on the effects of circRNA on proliferation, metastasis, apoptosis, metabolism, and drug resistance in kidney, bladder, and prostate cancers.

LncRNAs has been identified as regulators of Myeloid-derived suppressor cells in lung cancer

Lung tumours are widespread pathological conditions that attract much attention due to their high incidence of death. The immune system contributes to the progression of these diseases, especially non-small cell lung cancer, resulting in the fast evolution of immune-targeted therapy. Myeloid-derived suppressor cells (MDSCs) have been suggested to promote the progression of cancer in the lungs by suppressing the immune response through various mechanisms. Herein, we summarized the clinical studies on lung cancer related to MDSCs. However, it is noteworthy to mention the discovery of long non-coding RNAs (lncRNAs) that had different phenotypes and could regulate MDSCs in lung cancer. Therefore, by reviewing the different phenotypes of lncRNAs and their regulation on MDSCs, we summarized the lncRNAs' impact on the progression of lung tumours. Data highlight LncRNAs as anti-cancer agents. Hence, we aim to discuss their possibilities to inhibit tumour growth and trigger the development of immunosuppressive factors such as MDSCs in lung cancer through the regulation of lncRNAs. The ultimate purpose is to propose novel and efficient therapy methods for curing patients with lung tumours.

mRNA COVID-19 Vaccines-Facts and Hypotheses on Fragmentation and Encapsulation

BACKGROUND

The adventure of the mRNA vaccine began thirty years ago in the context of influenza. This consisted in encapsulating the mRNA coding for a viral protein in a lipid particle. We show how the mRNA encoding S protein has been modified for that purpose in the context of the anti-SARS-CoV-2 vaccination.

RESULTS

by using data coming from genetic and epidemiologic databases, we show the theoretical possibility of fragmentation of this mRNA into small RNA sequences capable of inhibiting important bio-syntheses such as the production of beta-globin.

DISCUSSION

we discuss two aspects related to mRNA vaccine: (i) the plausibility of mRNA fragmentation, and (ii) the role of liposomal nanoparticles (LNPs) used in the vaccine and their impact on mRNA biodistribution.

CONCLUSION

we insist on the need to develop lipid nanoparticles allowing personalized administration of vaccines and avoiding adverse effects due to mRNA fragmentation and inefficient biodistribution. Hence, we recommend (i) adapting the mRNA of vaccines to the least mutated virus proteins and (ii) personalizing its administration to the categories of chronic patients at risk most likely to suffer from adverse effects.

circPVT1 and PVT1/AKT3 show a role in cell proliferation, apoptosis, and tumor subtype-definition in small cell lung cancer

Small cell lung cancer (SCLC) is treated as a homogeneous disease, although the expression of NEUROD1, ASCL1, POU2F3, and YAP1 identifies distinct molecular subtypes. The MYC oncogene, amplified in SCLC, was recently shown to act as a lineage-specific factor to associate subtypes with histological classes. Indeed, MYC-driven SCLCs show a distinct metabolic profile and drug sensitivity. To disentangle their molecular features, we focused on the co-amplified PVT1, frequently overexpressed and originating circular (circRNA) and chimeric RNAs. We analyzed hsa_circ_0001821 (circPVT1) and PVT1/AKT3 (chimPVT1) as examples of such transcripts, respectively, to unveil their tumorigenic contribution to SCLC. In detail, circPVT1 activated a pro-proliferative and anti-apoptotic program when over-expressed in lung cells, and knockdown of chimPVT1 induced a decrease in cell growth and an increase of apoptosis in SCLC in vitro. Moreover, the investigated PVT1 transcripts underlined a functional connection between MYC and YAP1/POU2F3, suggesting that they contribute to the transcriptional landscape associated with MYC amplification. In conclusion, we have uncovered a functional role of circular and chimeric PVT1 transcripts in SCLC; these entities may prove useful as novel biomarkers in MYC-amplified tumors.

High-fat diet induced cyclophilin B enhances STAT3/lncRNA-PVT1 feedforward loop and promotes growth and metastasis in colorectal cancer

High-fat diet (HFD) has been implicated to promote colorectal cancer (CRC). Recently, oncogene Cyclophilin B (CypB) is reported to be induced by cholesterol. However, the role of CypB in CRC carcinogenesis and metastasis associated with HFD remains unknown. In the present study, we showed that HFD-induced CypB enhances proliferation and metastasis through an inflammation-driven circuit, including Signal Transducer and Activator of Transcription 3 (STAT3)-triggered transcription of lncRNA-PVT1, and its binding with CypB that promotes activation of STAT3. CypB was found to be upregulated in CRC, which was correlated with elevated body mass index and poor prognosis. HFD induced CypB expression and proinflammatory cytokines in colon of mice. Besides, CypB restoration facilitated growth, invasion and metastasis in CRC cells both in vitro and in vivo. Moreover, RIP sequencing data identified lncRNA-PVT1 as a functional binding partner of CypB. Mechanistically, PVT1 increased the phosphorylation and nuclear translocation of STAT3 in response to IL-6, through directly interaction with CypB, which impedes the binding of Suppressors Of Cytokine Signalling 3 (SOCS3) to STAT3. Furthermore, STAT3 in turn activated PVT1 transcription through binding to its promoter, forming a regulatory loop. Finally, this CypB/STAT3/PVT1 axis was verified in TCGA datasets and CRC tissue arrays. Our data revealed that CypB linked HFD and CRC malignancy by enhancing the CypB/STAT3/PVT1 feedforward axis and activation of STAT3.

Tumour Derived Extracellular Vesicles: Challenging Target to Blunt Tumour Immune Evasion

Simple Summary

Tumour onset and development occur because of specific immune support. The immune system, which is originally able to perceive and eliminate incipient cancer cells, becomes suppressed and hijacked by cancer. For these purposes, tumour cells use extracellular vesicles (TEVs). Specific molecular composition allows TEVs to reprogram immune cells towards tumour tolerance. Circulating TEVs move from their site of origin to other organs, preparing “a fertile soil” for metastasis formation. This implies that TEV molecular content can provide a valuable tool for cancer biomarker discovery and potential targets to reshape the immune system into tumour recognition and eradication.

Abstract

Control of the immune response is crucial for tumour onset and progression. Tumour cells handle the immune reaction by means of secreted factors and extracellular vesicles (EV). Tumour-derived extracellular vesicles (TEV) play key roles in immune reprogramming by delivering their cargo to different immune cells. Tumour-surrounding tissues also contribute to tumour immune editing and evasion, tumour progression, and drug resistance via locally released TEV. Moreover, the increase in circulating TEV has suggested their underpinning role in tumour dissemination. This review brings together data referring to TEV-driven immune regulation and antitumour immune suppression. Attention was also dedicated to TEV-mediated drug resistance.

Prognostic value and potential mechanism of long non-coding RNA Lnc-SMIM20-1 in acute myeloid leukemia

OBJECTIVES

Acute myeloid leukemia (AML) is a common hematologic malignancy with high heterogeneity and poor prognosis. Although long non-coding RNAs (lncRNAs) have been used as biomarkers for tumors, the clinical relevance of numerous lncRNAs in AML remains to be investigated.

RESEARCH DESIGN AND METHODS

Differentially expressed lncRNAs between AML and normal peripheral blood samples were identified using DESeq2. Pan-cancer analysis was performed by GEPIA tool. Kaplan-Meier survival curve was applied for prognosis analysis. KEGG pathway analysis and GSEA were used for functional enrichment. The ceRNA network was constructed by GDCRNAtools.

RESULTS

Lnc-SMIM20-1 was most highly expressed in AML and up-regulated in the TCGA-AML cohort compared to normal tissues. Patients with high expression of Lnc-SMIM20-1 had poor overall prognosis both in the TCGA adult AML cohort and the TARGET pediatric AML cohort, no matter whether they were treated with chemotherapy or allo-HSCT. Lnc-SMIM20-1 might participate in cancer-associated signaling pathways and immune-related signaling pathways by interacting with four microRNAs and 20 mRNAs.

CONCLUSION

Lnc-SMIM20-1 was up-regulated in AML acting as a stable poor prognostic factor. The prognostic impact of Lnc-SMIM20-1 cannot be overcome by allo-HSCT. Our findings provide insight into the clinical relevance of Lnc-SMIM20-1 in AML; aiming to progress the development of novel therapeutics.

Roles of circRNAs in hematological malignancies

As one of the leading causes of death, hematologic malignancies are associated with an ever-increasing incidence, and drug resistance and relapse of patients after treatment represent clinical challenges. Therefore, there are pressing demands to uncover biomarkers to indicate the development, progression, and therapeutic targets for hematologic malignancies. Circular RNAs (circRNAs) are covalently closed circular-single-stranded RNAs whose biosynthesis is regulated by various factors and is widely-expressed and evolutionarily conserved in many organisms and expressed in a tissue−/cell-specific manner. Recent reports have indicated that circRNAs plays an essential role in the progression of hematological malignancies. However, circRNAs are difficult to detect with low abundance using conventional techniques. We need to learn more information about their features to develop new detection methods. Herein, we sought to retrospect the current knowledge about the characteristics of circRNAs and summarized research on circRNAs in hematological malignancies to explore a potential direction.

CircRNAs: novel therapeutic targets in multiple myeloma

BACKGROUND

Circular RNA (circRNA) is a type of non-coding RNA that has recently attracted the attention of researchers. Multiple myeloma (MM) is a hematological malignancy with a dismal prognosis that indicates a pressing need for better treatment alternatives, particularly in terms of biological indicators. According to recent research findings, the presence of circRNA is also closely related to the incidence and progression of malignant hemopathy. There have been, however, only a few investigations of circRNA in MM.

MATERIAL AND METHODS

This review will be on the biological properties and functions of circRNA in MM and a discussion of the clinical utility of circRNA in the diagnosis, prognosis, and treatment of MM.

CONCLUSIONS

CircRNA is involved in gene transcription, translation, and epigenetic modification as well as the regulation of cancer cell proliferation, invasion, and metastasis, and hence, promotes or inhibits the occurrence and progression of MM. Therefore, circRNA holds promise as a potential future MM biomarker.

Advances in the Study of circRNAs in Hematological Malignancies

Circular RNAs (circRNAs) are non–protein-coding RNAs that have a circular structure and do not possess a 5` cap or 3` poly-A tail. Their structure is more stable than that of linear RNAs, and they are difficult to deform via hydrolysis. Advancements in measurement technology such as RNA sequencing have enabled the detection of circRNAs in various eukaryotes in both in vitro and in vivo studies. The main function of circRNAs involves sponging of microRNAs (MiRNAs) and interaction with proteins associated with physiological and pathological processes, while some circRNAs are involved in translation. circRNAs act as tumor suppressors or oncogenes during the development of many tumors and are emerging as new diagnostic and prognostic biomarkers. They also affect resistance to certain chemotherapy drugs such as imatinib. The objective of this review is to investigate the expression and clinical significance of circRNAs in hematological malignancies. We will also explore the effect of circRNAs on proliferation and apoptosis in hematological malignancy cells and their possible use as biomarkers or targets to determine prognoses. The current literature indicates that circRNAs may provide new therapeutic strategies for patients with hematologic malignancies.

Circular RNAs Involve in Immunity of Digestive Cancers From Bench to Bedside: A Review

The immune system plays a complex role in tumor formation and development. On the one hand, immune surveillance can inhibit the growth of tumors; on the other hand, immune evasion of tumors can create conditions conducive for tumor development and growth. CircRNAs are endogenous non-coding RNAs with a covalently closed loop structure that are abundantly expressed in eukaryotic organisms. They are characterized by stable structure, rich diversity, and high evolutionary conservation. In particular, circRNAs play a vital role in the occurrence, development, and treatment of tumors through their unique functions. Recently, the incidence and mortality of digestive cancers, especially those of gastric cancer, colorectal cancer, and liver cancer, have remained high. However, the functions of circRNAs in digestive cancers immunity are less known. The relationship between circRNAs and digestive tumor immunity is systematically discussed in our paper for the first time. CircRNA can influence the immune microenvironment of gastrointestinal tumors to promote their occurrence and development by acting as a miRNA molecular sponge, interacting with proteins, and regulating selective splicing. The circRNA vaccine even provides a new idea for tumor immunotherapy. Future studies should be focused on the location, transportation, and degradation mechanisms of circRNA in living cells and the relationship between circRNA and tumor immunity. This paper provides a new idea for the diagnosis and treatment of gastrointestinal tumors.

Clinical Value of Serum miRNA in Patients with Acute Promyelocytic Leukemia

Objective

To explore the clinical value of specific miRNA in patients with acute promyelocytic leukemia.

Methods

129 patients with acute promyelocytic leukemia diagnosed in our hospital from January 2015 to January 2020 were selected as the observation group. At the same time, 74 patients with nonacute promyelocytic leukemia who underwent bone marrow aspiration were included as the control group. The expression levels of miR-126-5p and miR-13, different characteristic parameters, and prognosis were compared between the two groups, and the clinical significance of miR-126-5p and miR-13 in acute promyelocytic leukemia was analyzed.

Results

The expression of miR-126-5p (12.31 ± 2.25 versus 17.30 ± 3.28) and miR-13 (16.05 ± 3.47 versus 21.66 ± 2.18) in the observation group was significantly lower than that in the control group (P < 0.05). The expression level of miR-126-5p was significantly correlated with lactate dehydrogenase level, HGB level, NPM1 mutant type, and complete remission (P < 0.05). The expression level of miR-13 was significantly correlated with HGB level, NPM1 mutant type, and complete remission (P < 0.05). Both expression levels of miR-126-5p and miR-13 were not correlated with sex, age, WBC, PLT, proportion of bone marrow primordial cells, hepatomegaly, splenomegaly, lymph node enlargement, and FLT3-ITD (P > 0.05). Cox multivariate regression analysis showed that peripheral blood WBC, bone marrow blast cell count, and miR-126-5p and miR-13 were prognostic factors in patients with acute promyelocytic leukemia (P < 0.05). The sensitivity, specificity, accuracy, and AUC of serum miR-126-5p prediction were 75.83%, 84.56%, 82.17%, and 0.729, respectively. The sensitivity, specificity, accuracy, and AUC of serum miR-13 prediction were 78.64%, 88.49%, 86.20% and 0.882, respectively.

Conclusion

Serum miR-126-5p and miR-13 are closely related to the prognosis of patients with acute promyelocytic leukemia. Serum miR-126-5p and miR-13 can be used as reliable indexes to predict the prognosis of patients.

Unravelling similarities and differences in the role of circular and linear PVT1 in cancer and human disease

The plasmacytoma variant translocation 1 (PVT1) is a long non-coding RNA gene involved in human disease, mainly in cancer onset/progression. Although widely analysed, its biological roles need to be further clarified. Notably, functional studies on PVT1 are complicated by the occurrence of multiple transcript variants, linear and circular, which generate technical issues in the experimental procedures used to evaluate its impact on human disease. Among the many PVT1 transcripts, the linear PVT1 (lncPVT1) and the circular hsa_circ_0001821 (circPVT1) are frequently reported to perform similar pathologic and pro-tumorigenic functions when overexpressed. The stimulation of cell proliferation, invasion and drug resistance, cell metabolism regulation, and apoptosis inhibition is controlled through multiple targets, including MYC, p21, STAT3, vimentin, cadherins, the PI3K/AKT, HK2, BCL2, and CASP3. However, some of this evidence may originate from an incorrect evaluation of these transcripts as two separate molecules, as they share the lncPVT1 exon-2 sequence. We here summarise lncPVT1/circPVT1 functions by mainly focusing on shared pathways, pointing out the potential bias that may exist when the biological role of each transcript is analysed. These considerations may improve the knowledge about lncPVT1/circPVT1 and their specific targets, which deserve further studies due to their diagnostic, prognostic, and therapeutic potential.

Circular RNA as a Novel Biomarker for Diagnosis and Prognosis and Potential Therapeutic Targets in Multiple Myeloma

Circular RNAs (circRNAs) are a novel type of covalently closed RNAs involved in several physiological and pathological processes. They display tissue-specific expression and are constant, abundant, and highly conserved, making them perfect markers for diagnosis and prognosis. Several studies have proposed that circRNAs are also differentially produced in malignancies where they have oncogenic effects. Furthermore, circRNAs affecting microRNAs modify the expression profile of several transcription factors which play essential roles in tumors. CircRNAs within the hematopoietic compartment were identified as modulators of mechanisms able to enhance or suppress tumor progression in blood malignancies. Moreover, several circRNAs were suggested to confer resistance to the conventional drugs employed in hematopoietic cancers. In this review, we highlight the growing role and the controlling mechanisms by which circRNAs modify multiple myeloma genesis. We propose that circRNAs can be considered as potential diagnostic and prognostic markers, can induce chemoresistance, and might represent novel therapeutic targets for multiple myeloma.

Ferroptosis‑related long non‑coding RNAs and the roles of LASTR in stomach adenocarcinoma

Ferroptosis is a form of programmed cell death that participates in diverse physiological processes. Increasing evidence suggests that long noncoding RNAs (lncRNAs) regulate ferroptosis in tumors, including stomach adenocarcinoma (STAD). In the present study, RNA-sequencing data from The Cancer Genome Atlas database and ferroptosis-related markers from the FerrDb data resource were analyzed to select differentially expressed lncRNAs. Univariate and multivariate Cox regression analyses were performed on these differentially expressed lncRNAs to screen 12 lncRNAs linked with overall survival (OS) and 13 associated with progression-free survival (PFS). Subsequently, two signatures for predicting OS and PFS were established based on these lncRNAs. Kaplan-Meier analyses indicated that the high-risk group of patients with STAD had relatively poor prognosis. The areas under the receiver operating characteristic curves of the two signatures indicated their excellent efficacy in predicting STAD prognosis. In addition, the effect of the lncRNA LASTR on proliferation and migration in gastric cancer was confirmed and the relationship between LASTR and ferroptosis was initially explored through experiments. These results provide potential novel targets for tumor treatment and promote personalized medicine.

CircPVT1: a pivotal circular node intersecting Long Non-Coding-PVT1 and c-MYC oncogenic signals

The role of circular RNAs in oncogenesis has begun to be widely studied in recent years, due to the significant impact that these molecules have in disease pathogenesis, as well as their potential for the future of innovative therapies. Moreover, due to their characteristically circular shape, circular RNAs are very resistant molecules to RNA degradation whose levels are easily assessed in body fluids. Accordingly, they represent an opportunity for the discovery of new diagnostic and prognostic markers in a wide range of diseases. Among circular RNAs, circPVT1 is a rather peculiar one that originates from the circularization of the exon 2 of the PVT1 gene that encodes a pro-tumorigenic long non-coding RNA named lncPVT1. There are a few examples of circular RNAs that derive from a locus producing another non-coding RNA. Despite their apparent transcriptional independence, which occurs using two different promoters, a possible synergistic effect in tumorigenesis cannot be excluded considering that both have been reported to correlate with the oncogenic phenotype. This complex mechanism of regulation appears to also be controlled by c-MYC. Indeed, the PVT1 locus is located only 53 Kb downstream c-MYC gene, a well-known oncogene that regulates the expression levels of about 15% of all genes. Here, we review circPVT1 origin and biogenesis highlighting the most important mechanisms through which it plays a fundamental role in oncogenesis, such as the well-known sponge activity on microRNAs, as well as its paradigmatic interactome link with lncPVT1 and c-MYC expression.

hsa_circ_0072389, hsa_circ_0072386, hsa_circ_0008621, hsa_circ_0072387, and hsa_circ_0072391 aggravate glioma via miR-338-5p/IKBIP

Glioma is a primary intracranial tumor with high morbidity and mortality. We acquired miR-338-5p, which suppresses the development of glioma, from the GEO and CGGA databases. In addition, we predicted that hsa_circ_0072389, hsa_circ_0072386, hsa_circ_0008621, hsa_circ_0072387, and hsa_circ_0072391 could relieve the silencing of IKBIP by miR-338-5p. By analyzing genes related to IKBIP expression, possible pathways affecting glioma were identified. This study provides new ideas for investigating multiple circRNAs in ceRNAs.

Circular RNA PVT1 inhibits tendon stem/progenitor cell senescence by sponging microRNA-199a-5p

Tendon stem/progenitor cell (TSPC) senescence can lead to age-dependent tendon maladies and undermines both tendon repair and replacement capacity in humans. The mechanisms underlying TSPC senescence and sensitivity to adverse factors are complicated. In this study, we analyzed involvement of the circular RNA (circRNA) PVT1 (circPVT1) in TSPC senescence. circPVT1 expression was found to be significantly diminished in human TSPCs under prolonged in vitro culture. Accordingly, circPVT1 knockdown promoted senescence progression and suppressed self renewal, migration, and tenogenic differentiation of TSPCs. Furthermore, we found that circPVT1 directly targets microRNA (miR)-199a-5p thereby attenuating its negative regulation of SIRT1 expression. Either miR-199a-5p inhibition or SIRT1 overexpression attenuated the senescence-boosting effect of circPVT1 knockdown, implying that circPVT1 suppresses TSPC senescence in part by upregulating the miR-199a-5p-SIRT1 signaling axis. Our findings conclusively explain the major roles of circPVT1 in TSPC senescence regulation; circPVT1 is a novel potential therapeutic target for reducing tendon senescence.

The role of circular RNA plasmacytoma variant translocation 1 as a biomarker for prognostication of acute myeloid leukemia

OBJECTIVE

Circular RNA plasmacytoma variant translocation 1 (circ-PVT1) has been reported to be an oncogene and serves as a prognostic biomarker in several solid cancers and hematological malignancies. However, no study has been performed on the tumorigenesis role of circ-PVT1 in acute myeloid leukemia (AML). Thus, this study aimed to evaluate the correlation of circ-PVT1 with disease risk, clinical characteristics, cytogenetics/molecular genetics, and prognosis of AML.

METHODS

A total of 68 de novo AML patients, 30 disease controls and 30 health donors were enrolled in this study. Circ-PVT1 expression in bone marrow (BM) was determined. Complete remission (CR) status after induction therapy, event-free survival (EFS) and overall survival (OS) were evaluated in AML patients.

RESULTS

Circ-PVT1 expression was different among AML patients, disease controls and health donors, which was highest in AML patients, followed by disease controls and lowest in health donors. Meanwhile, circ-PVT1 could distinguish AML patients from health donors and disease controls by receiver operating characteristic curve analysis. Furthermore, circ-PVT1 was correlated with BM blasts and FLT3-ITD mutation, but not other clinical features, such as French-American-Britain subtypes in AML patients. Moreover, circ-PVT1 expression was lower in AML patients with CR compared with those without CR. Besides, high circ-PVT1 expression was correlated with shorter EFS and OS in AML patients. After adjustment by multivariate Cox's regression analysis, higher circ-PVT1 expression was an independent factor in predicting shorter EFS and OS for AML patients.

CONCLUSION

Circ-PVT1 potentially serves as a biomarker for evaluating the prognosis of AML patients.

Circular RNA Pvt1 oncogene (CircPVT1) promotes the progression of papillary thyroid carcinoma by activating the Wnt/β-catenin signaling pathway and modulating the ratio of microRNA-195 (miR-195) to vascular endothelial growth factor A (VEGFA) expression

Circular RNAs (circRNAs) have been reported to be involved in the progression of papillary thyroid carcinoma (PTC). However, the role of circular RNA Pvt1 oncogene (circPVT1) in PTC has rarely been reported. In this study, we aimed to investigate the function and mechanism of circPVT1 in PTC. The expression level of circPVT1, miR-195 and VEGFA were determined by reverse transcription‑quantitative PCR (RT‑qPCR). Fisher's exact test was used to analyze the correlation between circPVT1 expression and PTC clinical features. Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) staining assay and transwell assay were conducted to evaluate the cell proliferation, migration and invasion ability. Dual-luciferase reporter and Western blot assay were conducted for evaluating the correlation between miR-195 and circPVT1 or VEGFA. The results of RT-PCR showed that the expression level of circPVT1 was significantly upregulated in PTC tissues and cell lines. After downregulating circPVT1 expression in PTC cells, the abilities of cell proliferation, migration, and invasion were obviously suppressed, and the Wnt/β-catenin signaling pathway was also repressed. Besides, miR-195 could both bind to PVT1 and VEGFA, while PVT1 could promote the expression of VEGFA by binding to miR-195. Downregulation of VEGFA expression in PTC cells revealed weakened cell proliferation, migration, and invasion capacities, and restrained Wnt/β-catenin signaling pathway. Therefore, we demonstrated that circPVT1 could promote VEGFA expression by sponging miR-195. CircPVT1 could serve as a molecule sponge for miR-195 and mediate the ceRNA network to promote the expression of VEGFA, thus contributed to the malignant progression of PTC.

Genome Instability in Multiple Myeloma: Facts and Factors

Multiple myeloma (MM) is a malignant neoplasm of terminally differentiated immunoglobulin-producing B lymphocytes called plasma cells. MM is the second most common hematologic malignancy, and it poses a heavy economic and social burden because it remains incurable and confers a profound disability to patients. Despite current progress in MM treatment, the disease invariably recurs, even after the transplantation of autologous hematopoietic stem cells (ASCT). Biological processes leading to a pathological myeloma clone and the mechanisms of further evolution of the disease are far from complete understanding. Genetically, MM is a complex disease that demonstrates a high level of heterogeneity. Myeloma genomes carry numerous genetic changes, including structural genome variations and chromosomal gains and losses, and these changes occur in combinations with point mutations affecting various cellular pathways, including genome maintenance. MM genome instability in its extreme is manifested in mutation kataegis and complex genomic rearrangements: chromothripsis, templated insertions, and chromoplexy. Chemotherapeutic agents used to treat MM add another level of complexity because many of them exacerbate genome instability. Genome abnormalities are driver events and deciphering their mechanisms will help understand the causes of MM and play a pivotal role in developing new therapies.

NFIB-Mediated lncRNA PVT1 Aggravates Laryngeal Squamous Cell Carcinoma Progression via the miR-1301-3p/MBNL1 Axis

Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumors of head and neck cancers. In the past decades, although the therapy strategies of LSCC have made considerable improvement, the terrible outcomes of LSCC still bring an enormous burden to the world health care system. Novel therapeutic targets for LSCC are urgently needed. lncRNAs exert important roles in various biological progressions, including LSCC. Here, we aimed to investigate the function of lncRNA PVT1 in LSCC progression and its underlying molecular mechanisms. By conducting multiple experiments, our results showed that lncRNA PVT1 was upregulated in LSCC cell lines and regulated LSCC cell proliferation, apoptosis, and its cell susceptibility to natural killer (NK) cells. Moreover, it was found that lncRNA PVT1 promotes MBNL1 expression to regulate LSCC cellular progression through sponging miR-1301-3p. Our study might provide novel targets for LSCC basic research or clinical management.

Long Noncoding Competing Endogenous RNA Networks in Pancreatic Cancer

Pancreatic cancer (PC) is a highly malignant disease characterized by insidious onset, rapid progress, and poor therapeutic effects. The molecular mechanisms associated with PC initiation and progression are largely insufficient, hampering the exploitation of novel diagnostic biomarkers and development of efficient therapeutic strategies. Emerging evidence recently reveals that noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), extensively participate in PC pathogenesis. Specifically, lncRNAs can function as competing endogenous RNAs (ceRNAs), competitively sequestering miRNAs, therefore modulating the expression levels of their downstream target genes. Such complex lncRNA/miRNA/mRNA networks, namely, ceRNA networks, play crucial roles in the biological processes of PC by regulating cell growth and survival, epithelial-mesenchymal transition and metastasis, cancer stem cell maintenance, metabolism, autophagy, chemoresistance, and angiogenesis. In this review, the emerging knowledge on the lncRNA-associated ceRNA networks involved in PC initiation and progression will be summarized, and the potentials of the competitive crosstalk as diagnostic, prognostic, and therapeutic targets will be comprehensively discussed.

Regulatory noncoding RNAs: potential biomarkers and therapeutic targets in acute myeloid leukemia

The noncoding RNAs (ncRNA) comprise a substantial segment of the human transcriptome and have emerged as key elements of cellular homeostasis and disease pathogenesis. Dysregulation of these ncRNAs by alterations in the primary RNA motifs and/or aberrant expression levels is relevant in various diseases, especially cancer. The recent research advances indicate that ncRNAs regulate vital oncogenic processes, including hematopoietic cell differentiation, proliferation, apoptosis, migration, and angiogenesis. The ever-expanding role of ncRNAs in cancer progression and metastasis has sparked interest as potential diagnostic and prognostic biomarkers in acute myeloid leukemia. Moreover, advances in antisense oligonucleotide technologies and pharmacologic discoveries of small molecule inhibitors in targeting RNA structures and RNA-protein complexes have opened newer avenues that may help develop the next generation anti-cancer therapeutics. In this review, we have discussed the role of ncRNA in acute myeloid leukemia and their utility as potential biomarkers and therapeutic targets.

MustSeq, an alternative approach for multiplexible strand-specific 3' end sequencing of mRNA transcriptome confers high efficiency and practicality

RNA-seq has been widely used to reveal the molecular mechanism of variants of life process. We have developed an alternative method, MustSeq, which generates multiple second strands along a single 1^st strand cDNA by random-priming initiation, immediately after reverse transcription for each RNA extract using sample-barcoded poly-dT primers, then 3' ends-enriching PCR is applied to construct the library. Unlike the conventional RNA seq, MustSeq avoids procedures such as mRNA isolation, fragmentation and RNA 5'-end capture, enables early pooling of multiple samples, and requires only one twentieth of sequencing reads of full-length sequencing. We demonstrate the power and features of MustSeq comparing with TruSeq and NEBNext RNA-seq, two conventional full-length methods and QuantSeq, an industrial 3' end method. In cancer cell lines, the reads distribution of CDS-exon as well as genes, lncRNAs and GO terms detected by MustSeq are closer than QuantSeq to TruSeq. In mouse hepatocarcinoma and healthy livers, MustSeq enriches the same pathways as by NEBNext, and reveals the molecular profile of carcinogenesis. Overall MustSeq is a robust and accurate RNA-seq method allowing efficient library construction, sequencing and analysis, particularly valuable for analysis of differentially expressed genes with a large number of samples. MustSeq will greatly accelerate the application of bulk RNA-seq on different fields, and potentially applicable for single cell RNA-seq.