Transcribed ultraconserved region 339 promotes carcinogenesis by modulating tumor suppressor microRNAs

Exosome regulation of immune response mechanism: Pros and cons in immunotherapy

Due to its multiple features, including the ability to orchestrate remote communication between different tissues, the exosomes are the extracellular vesicles arousing the highest interest in the scientific community. Their size, established as an average of 30-150 nm, allows them to be easily uptaken by most cells. According to the type of cells-derived exosomes, they may carry specific biomolecular cargoes used to reprogram the cells they are interacting with. In certain circumstances, exosomes stimulate the immune response by facilitating or amplifying the release of foreign antigens-killing cells, inflammatory factors, or antibodies (immune activation). Meanwhile, in other cases, they are efficiently used by malignant elements such as cancer cells to mislead the immune recognition mechanism, carrying and transferring their cancerous cargoes to distant healthy cells, thus contributing to antigenic invasion (immune suppression). Exosome dichotomic patterns upon immune system regulation present broad advantages in immunotherapy. Its perfect comprehension, from its early biogenesis to its specific interaction with recipient cells, will promote a significant enhancement of immunotherapy employing molecular biology, nanomedicine, and nanotechnology.

GC-biased gene conversion drives accelerated evolution of ultraconserved elements in mammalian and avian genomes

Ultraconserved elements (UCEs) are the most conserved regions among the genomes of evolutionarily distant species and are thought to play critical biological functions. However, some UCEs rapidly evolved in specific lineages, and whether they contributed to adaptive evolution is still controversial. Here, using an increased number of sequenced genomes with high taxonomic coverage, we identified 2191 mammalian UCEs and 5938 avian UCEs from 95 mammal and 94 bird genomes, respectively. Our results show that these UCEs are functionally constrained and that their adjacent genes are prone to widespread expression with low expression diversity across tissues. Functional enrichment of mammalian and avian UCEs shows different trends indicating that UCEs may contribute to adaptive evolution of taxa. Focusing on lineage-specific accelerated evolution, we discover that the proportion of fast-evolving UCEs in nine mammalian and 10 avian test lineages range from 0.19% to 13.2%. Notably, up to 62.1% of fast-evolving UCEs in test lineages are much more likely to result from GC-biased gene conversion (gBGC). A single cervid-specific gBGC region embracing the uc.359 allele significantly alters the expression of Nova1 and other neural-related genes in the rat brain. Combined with the altered regulatory activity of ancient gBGC-induced fast-evolving UCEs in eutherians, our results provide evidence that synergy between gBGC and selection shaped lineage-specific substitution patterns, even in the most constrained regulatory elements. In summary, our results show that gBGC played an important role in facilitating lineage-specific accelerated evolution of UCEs, and further support the idea that a combination of multiple evolutionary forces shapes adaptive evolution.

Construction of a three-component regulatory network of transcribed ultraconserved regions for the identification of prognostic biomarkers in gastric cancer

Altered expression and functional roles of the transcribed ultraconserved regions (T-UCRs), as genomic sequences with 100% conservation between the genomes of human, mouse, and rat, in the pathophysiology of neoplasms has already been investigated. Nevertheless, the relevance of the functions for T-UCRs in gastric cancer (GC) is still the subject of inquiry. In the current study, we first used a genome-wide profiling approach to analyze the expression of T-UCRs in GC patients. Then, we constructed a three-component regulatory network and investigated potential diagnostic and prognostic values of the T-UCRs. The Cancer Genome Atlas Stomach Adenocarcinoma (TCGA-STAD) dataset was used as a resource for the RNA-sequencing data. FeatureCounts was utilized to quantify the number of reads mapped to each T-UCR. Differential expression analysis was then conducted using DESeq2. In the following, interactions between T-UCRs, microRNAs (miRNAs), and messenger RNAs (mRNAs) were combined into a three-component network. Enrichment analyses were performed and a protein-protein interaction (PPI) network was constructed. The R Survival package was utilized to identify survival-related significantly differentially expressed T-UCRs (DET-UCRs). Using an in-house cohort of GC tissues, expression of two DET-UCRs was furthermore experimentally verified. Our results showed that several T-UCRs were dysregulated in TCGA-STAD tumoral samples compared to nontumoral counterparts. The three-component network was constructed which composed of DET-UCRs, miRNAs, and mRNAs nodes. Functional enrichment and PPI network analyses revealed important enriched signaling pathways and gene ontologies such as "pathway in cancer" and regulation of cell proliferation and apoptosis. Five T-UCRs were significantly correlated with the overall survival of GC patients. While no expression of uc.232 was observed in our in-house cohort of GC tissues, uc.343 showed an increased expression, although not statistically significant, in gastric tumoral tissues. The constructed three-component regulatory network of T-UCRs in GC presents a comprehensive understanding of the underlying gene expression regulation processes involved in tumor development and can serve as a basis to investigate potential prognostic biomarkers and therapeutic targets.

Transcribed Ultraconserved Regions: New regulators in cancer signaling and potential biomarkers

The ultraconserved regions (UCRs) are 481 genomic elements, longer than 200 bp, 100% conserved in human, mouse, and rat genomes. Usually, coding regions are more conserved, but more than 80% of UCRs are either intergenic or intronic, and many of them produce long non-coding RNAs (lncRNAs). Recently, the deregulated expression of transcribed UCRs (T-UCRs) has been associated with pathological conditions. But, differently from many lncRNAs with recognized crucial effects on malignant cell processes, the role of T-UCRs in the control of cancer cell networks is understudied. Furthermore, the potential utility of these molecules as molecular markers is not clear. Based on this information, the present review aims to organize information about T-UCRs with either oncogenic or tumor suppressor role associated with cancer cell signaling, and better describe T-UCRs with potential utility as prognosis markers. Out of 481 T-UCRs, 297 present differential expression in cancer samples, 23 molecules are associated with tumorigenesis processes, and 12 have more clear potential utility as prognosis markers. In conclusion, T-UCRs are deregulated in several tumor types, highlighted as important molecules in cancer networks, and with potential utility as prognosis markers, although further investigation for translational medicine is still needed.

First-line immunotherapy or angiogenesis inhibitor combined with chemotherapy for advanced non-small cell lung cancer with EGFR exon 20 insertions: Real-world evidence from China

BACKGROUND

Currently, survival benefit of immunotherapy in advanced non-small cell lung cancer (NSCLC) with EGFR exon 20 insertions (ex20ins) is controversial, though it generally indicates poor response and activity. Compared with standard chemotherapy in combination with bevacizumab, first-line chemotherapy plus immune checkpoint inhibitor (ICI) in advanced NSCLC with EGFR ex20ins remains elusive and lacks real-world evidence.

PATIENTS AND METHODS

A retrospective real-world study was conducted to evaluate clinical outcomes of chemotherapy alone (C), chemotherapy plus ICI (C + I), or chemotherapy plus angiogenesis inhibitors (C + A) as first-line strategies for advanced NSCLC patients with EGFR ex20ins. Investigator-assessed response and survival outcomes were compared between subgroups. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was conducted to reveal concomitant alterations and explore the molecular landscape of ex20ins.

RESULTS

A total of 164 patients were screened, identifying 35 kinds of ex20ins, and 122 cases treated with C, C + I, and C + A were finally included in the first-line analysis. C + A achieved much better objective response rate (ORR, 38.1% vs. 18.2%) and significant progression-free survival (PFS) benefit compared with C (median, 7.73 vs.5.93 months, HR = 0.60, 95% CI: 0.40-0.90, p = 0.014), and it showed similar ORR (38.1% vs. 40.0%), but higher disease control rate (DCR, 96.8% vs. 80.0%) and numerically longer median PFS (7.73 vs. 6.53 months, HR = 0.83, 95% CI: 0.44-1.56, p = 0.30) than C + I. There was no PFS difference between C + I and C, despite of PD-L1 expression or tumor mutational burden. KEGG analysis revealed concomitant upregulation of PI3K/AKT signaling might mediate intrinsic resistance to ICI in ex20ins.

CONCLUSION

First-line chemotherapy plus angiogenesis inhibitors might yield more survival benefits than chemotherapy alone for NSCLC with EGFR ex20ins, whereas, it suggests that chemotherapy in combination with ICI might not obtain a better survival benefit for this subset of patients. Activation of PI3K/AKT signaling might mediate intrinsic immunosuppression in NSCLC with EGFR ex20ins.

Long noncoding RNA uc.230/CUG-binding protein 1 axis sustains intestinal epithelial homeostasis and response to tissue injury

Intestinal epithelial integrity is commonly disrupted in patients with critical disorders, but the exact underlying mechanisms are unclear. Long noncoding RNAs transcribed from ultraconserved regions (T-UCRs) control different cell functions and are involved in pathologies. Here, we investigated the role of T-UCRs in intestinal epithelial homeostasis and identified T-UCR uc.230 as a major regulator of epithelial renewal, apoptosis, and barrier function. Compared with controls, intestinal mucosal tissues from patients with ulcerative colitis and from mice with colitis or fasted for 48 hours had increased levels of uc.230. Silencing uc.230 inhibited the growth of intestinal epithelial cells (IECs) and organoids and caused epithelial barrier dysfunction. Silencing uc.230 also increased IEC vulnerability to apoptosis, whereas increasing uc.230 levels protected IECs against cell death. In mice with colitis, reduced uc.230 levels enhanced mucosal inflammatory injury and delayed recovery. Mechanistic studies revealed that uc.230 increased CUG-binding protein 1 (CUGBP1) by acting as a natural decoy RNA for miR-503, which interacts with Cugbp1 mRNA and represses its translation. These findings indicate that uc.230 sustains intestinal mucosal homeostasis by promoting epithelial renewal and barrier function and that it protects IECs against apoptosis by serving as a natural sponge for miR-503, thereby preserving CUGBP1 expression.

Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma

BACKGROUND

Nuclear receptor subfamily 1 group H member 4 (NR1H4) have been reported in various cancer types, however, little is known about the clinical values and biological function in clear cell Renal cell carcinoma (ccRCC).

METHODS

The expression pattens of NR1H4 in ccRCC were investigated in clinical specimens, cell lines and publicly‑available databases. Cell Counting Kit-8 (CCK-8), colony formation, 5-ethynyl-2' -deoxyuridine (EdU), transwell and cell wound healing assays were performed to assess the biological functions of NR1H4 in 786-O ccRCC cells. Gene set enrichment analysis (GSEA), Flow Cytometry, quantitative real-time PCR (qRT-PCR), western blot and immunofluorescence were performed to explore the molecular mechanism of NR1H4 in ccRCC. We explored the early diagnostic value, prognostic value, genetic mutation and DNA methylation of NR1H4 by a comprehensive bioinformatics analysis based on the data published in the following databases: The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Kaplan-Meier Plotter, Gene Expression Profiling Interactive Analysis (GEPIA), UNIVERSITY OF CALIFORNIA SANTA CRUZ Xena (UCSC Xena), cBio Cancer Genomics Portal, MethSurv, SurvivalMeth and The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN). Its correlation with tumor-infiltrating immune cells in ccRCC was analyzed by Tumor Immune Estimation Resource 2.0 (TIMER2.0) and Tumor Immune System Interactions Database (TISIDB).

RESULTS

In this study, NR1H4 was found to be highly expressed in ccRCC tissues and ccRCC cell lines. Knockdown of NR1H4 significantly suppressed cancer cell proliferation, migration and invasion. Mechanistically, tumor-associated signaling pathways were enriched in the NR1H4 overexpression group and si-NR1H4 could induce the downregulation of Cyclin E2 (CCNE2). By bioinformatics analysis, NR1H4 was identified as highly expressed in stage I ccRCC with a high diagnostic accuracy (area under the receiver operating characteristic curve > 0.8). Genetic alteration and DNA methylation of NR1H4 were significantly associated with prognosis in ccRCC patients. Moreover, NR1H4 expression associated with immune cell infiltration levels in ccRCC, which provides a new idea for immunotherapy.

CONCLUSIONS

Our study indicated that NR1H4 might be a potential tumor biomarker and therapeutic target for ccRCC which could promote cancer cell proliferation, migration and invasion via regulating CCNE2.

Elevated Hexose-6-Phosphate Dehydrogenase Regulated by OSMR-AS1/hsa-miR-516b-5p Axis Correlates with Poor Prognosis and Dendritic Cells Infiltration of Glioblastoma

Objective Glioblastoma (GBM), a type of malignant glioma, is the most aggressive type of brain tumor and is associated with high mortality. Hexose-6-phosphate dehydrogenase (H6PD) has been detected in multiple tumors and is involved in tumor initiation and progression. However, the specific role and mechanism of H6PD in GBM remain unclear. Methods We performed pan-cancer analysis of expression and prognosis of H6PD in GBM using the Genotype-Tissue Expression Project (GTEx) and The Cancer Genome Atlas (TCGA). Subsequently, noncoding RNAs regulating H6PD expression were obtained by comprehensive analysis, including gene expression, prognosis, correlation, and immune infiltration. Finally, tumor immune infiltrates related to H6PD and survival were performed. Results Higher expression of H6PD was statistically significantly associated with an unfavorable outcome in GBM. Downregulation of hsa-miR-124-3p and hsa-miR-516b-5p in GBM was detected from GSE90603. Subsequently, OSMR-AS1 was observed in the regulation of H6PD via hsa-miR-516b-5p. Moreover, higher H6PD expression significantly correlated with immune infiltration of dendritic cells, immune checkpoint expression, and biomarkers of dendritic cells. Conclusions The OSMR-AS1/ miR-516b-5p axis was identified as the highest-potential upstream ncRNA-related pathway of H6PD in GBM. Furthermore, the present findings demonstrated that H6PD blockading might possess antitumor roles via regulating dendritic cell infiltration and immune checkpoint expression.

Transcribed Ultraconserved Regions in Cancer

Transcribed ultraconserved regions are putative lncRNA molecules that are transcribed from DNA that is 100% conserved in human, mouse, and rat genomes. This is notable, as lncRNAs are typically poorly conserved. TUCRs remain very understudied in many diseases, including cancer. In this review, we summarize the current literature on TUCRs in cancer with respect to expression deregulation, functional roles, mechanisms of action, and clinical perspectives.

The dark matter of the human genome and its role in human cancers

The transcribed ultra-conserved regions (T-UCRs) are a novel family of non-coding RNAs which are absolutely conserved (100%) across orthologous regions of the human, mouse, and rat genomes. T-UCRs represent a small portion of the human genome that is likely to be functional but does not code for proteins and is referred to as the "dark matter" of the human genome. Although T-UCRs are ubiquitously expressed, tissue- and disease-specific expression of T-UCRs have also been observed. Accumulating evidence suggests that T-UCRs are differentially expressed and involved in the malignant transformation of human tumors through various genetic and epigenetic regulatory mechanisms. Therefore, T-UCRs are novel candidate predisposing biomarkers for cancer development. T-UCRs have shown to drive malignant transformation of human cancers through regulating non-coding RNAs and/or protein coding genes. However, the functions and fate of most T-UCRs remain mysterious. Here, we review and highlight the current knowledge on these ultra-conserved elements in the formation and progression of human cancers.

Overexpression of ultraconserved region 83- induces lung cancer tumorigenesis

The expression of non-coding RNAs (ncRNAs) is dysregulated in human cancers. The transcribed ultraconserved regions (T-UCRs) express long ncRNAs involved in human carcinogenesis. T-UCRs are non-coding genomic sequence that are 100% conserved across humans, rats and mice. Conservation of genomic sequences across species intrinsically implies an essential functional role and so we considered the expression of T-UCRs in lung cancer. Using a custom microarray we analyzed the global expression of T-UCRs. Among these T-UCRs, the greatest variation was observed for antisense ultraconserved element 83 (uc.83-), which was upregulated in human lung cancer tissues compared with adjacent non cancerous tissues. Even though uc.83- is located within the long intergenic non-protein coding RNA 1876 (LINC01876) gene, we found that the transcribed uc.83- is expressed independently of LINC01876 and was cloned as a 1143-bp RNA gene. In this study, functional analysis confirmed important effects of uc.83- on genes involved in cell growth of human cells. siRNA against uc.83- decreased the growth of lung cancer cells while the upregulation through a vector overexpressing the uc.83- RNA increased cell proliferation. We also show the oncogenic function of uc.83- is mediated by the phosphorylation of AKT and ERK 1/2, two important biomarkers of lung cancer cell proliferation. Based on our findings, inhibition against uc.83- could be a future therapeutic treatment for NSCLC to achieve simultaneous blockade of pathways involved in lung carcinogenesis.

UC.183, UC.110, and UC.84 Ultra-Conserved RNAs Are Mutually Exclusive with miR-221 and Are Engaged in the Cell Cycle Circuitry in Breast Cancer Cell Lines

In the human genome, there are about 600 ultra-conserved regions (UCRs), long DNA sequences extremely conserved in vertebrates. We performed a large-scale study to quantify transcribed UCR (T-UCR) and miRNA levels in over 6000 cancer and normal tissue samples to find possible correlation between these kinds of regulatory molecules. Our analysis evidenced several non-coding RNAs showing negative co-regulation with miRNAs; among them, we focused on miR-221 to investigate any relationship with its pivotal role in the cell cycle. We have chosen breast cancer as model, using two cell lines with different phenotypes to carry out in vitro treatments with siRNAs against T-UCRs. Our results demonstrate that the expression of uc.183, uc.110, and uc.84 T-UCRs is mutually exclusive with miR-221 and is engaged in the regulation of CDKN1B expression. In addition, tests with a set of anticancer drugs, including BYL719, AZD5363, AZD8055, AZD7762, and XL765, revealed the modulation of specific T-UCRs without alteration of miR-221 levels.

The transcribed ultraconserved region uc.160+ enhances processing and A-to-I editing of the miR-376 cluster: hypermethylation improves glioma prognosis

Transcribed ultraconserved regions (T‐UCRs) are noncoding RNAs derived from DNA sequences that are entirely conserved across species. Their expression is altered in many tumor types, and, although a role for T‐UCRs as regulators of gene expression has been proposed, their functions remain largely unknown. Herein, we describe the epigenetic silencing of the uc.160+ T‐UCR in gliomas and mechanistically define a novel RNA–RNA regulatory network in which uc.160+ modulates the biogenesis of several members of the miR‐376 cluster. This includes the positive regulation of primary microRNA (pri‐miRNA) cleavage and an enhanced A‐to‐I editing on its mature sequence. As a consequence, the expression of uc.160+ affects the downstream, miR‐376‐regulated genes, including the transcriptional coregulators RING1 and YY1‐binding protein (RYBP) and forkhead box P2 (FOXP2). Finally, we elucidate the clinical impact of our findings, showing that hypermethylation of the uc.160+ CpG island is an independent prognostic factor associated with better overall survival in lower‐grade gliomas, highlighting the importance of T‐UCRs in cancer pathophysiology.

New insights into exosome mediated tumor-immune escape: Clinical perspectives and therapeutic strategies

Recent advances in extracellular vesicle biology have uncovered a substantial role in maintaining cell homeostasis in health and disease conditions by mediating intercellular communication, thus catching the scientific community's attention worldwide. Extracellular microvesicles, some called exosomes, functionally transfer biomolecules such as proteins and non-coding RNAs from one cell to another, influencing the local environment's biology. Although numerous advancements have been made in treating cancer patients with immune therapy, controlling the disease remains a challenge in the clinic due to tumor-driven interference with the immune response and inability of immune cells to clear cancer cells from the body. The present review article discusses the recent findings and knowledge gaps related to the role of exosomes derived from tumors and the tumor microenvironment cells in tumor escape from immunosurveillance. Further, we highlight examples where exosomal non-coding RNAs influence immune cells' response within the tumor microenvironment and favor tumor growth and progression. Therefore, exosomes can be used as a therapeutic target for the treatment of human cancers.

uc.77- Downregulation Promotes Colorectal Cancer Cell Proliferation by Inhibiting FBXW8-Mediated CDK4 Protein Degradation

Transcribed ultraconserved regions (T-UCRs) are a new type of long non-coding RNA, and the UCR has 481 segments longer than 200 base pairs that are 100% conserved between humans, rats, and mice. T-UCRs involved in colorectal cancer (CRC) have not been studied in detail. We performed T-UCR microarray analysis and found that uc.77- was significantly downregulated in CRC tissues and cell lines. Ectopic expression of uc.77- significantly inhibited the proliferation of CRC cells in vitro and the growth of xenograft tumors in nude mice in vivo. Mechanistic studies showed that uc.77- competed with FBXW8 mRNA for binding to microRNA (miR)-4676-5p through a competing endogenous RNA mechanism and inhibited the proliferation of CRC cells by negatively regulating CDK4. The present findings highlight the role of the uc.77-/miR-4676-5p/FBXW8 axis in CRC and identify uc.77- as a potential novel target for the treatment of CRC.

Overexpression of the transcribed ultraconserved region Uc.138 accelerates colon cancer progression

Ultraconserved regions (UCRs) are 481 genomic sequences with 100% identity across humans, rats, and mice. Increasing evidence suggests that non-coding RNAs transcribed from UCRs are involved in various diseases, especially cancers. The human transformer 2β gene (TRA2B) encodes a UCR (uc.138) that spans exon 2 and its neighboring introns. TRA2B4 RNA is the only transcript that contains the whole exon 2 among five spliced TRA2B RNA variants (TRA2B1-5). TRA2B4 is upregulated in colon cancer cell lines, although it is not translated to Tra2β protein because of its nuclear retention. Nevertheless, the clinical significance and biological functions of uc.138 in colon cancer cells remain unclear. In this study, RNA in situ hybridization showed that TRA2B4 was predominantly overexpressed in the nucleus of colon adenocarcinoma and adenoma. Overexpression of TRA2B4 in colon cancer HCT116 cells promoted cell proliferation by changing the expression of G2/M-related cell cycle regulators. Moreover, TRA2B4 increased migration and cell viability in a uc.138 sequence-dependent manner. TRA2B4 significantly enhanced tumorigenesis in vivo. Taken together, uc.138 encoded in TRA2B4 plays an oncogenic role in tumor progression and may become a potential biomarker and therapeutic target in colon cancer.

Premature MicroRNA-Based Therapeutic: A "One-Two Punch" against Cancers

Simple Summary

The current understanding of miRNA biology is greatly derived from studies on the guide strands and the passenger strands, also called miRNAs*, which are considered as carriers with no sense for long periods. As such, various studies alter the expression of guide strands by manipulating the expression of their primary transcripts or precursors, both of which are premature miRNAs. In this situation, the regulatory miRNA* species may interfere with the phenotypic interpretation against the target miRNA. However, such methods could manipulate the expression of two functionally synergistic miRNAs of the same precursor, leading to therapeutic potential against various diseases, including cancers. Premature miRNAs represent an underappreciated target reservoir and provide molecular targets for “one-two punch” against cancers. Examples of targetable miRNA precursors and available targeting strategies are provided in this review.

Abstract

Up-to-date knowledge regarding the biogenesis and functioning of microRNAs (miRNAs) has provided a much more comprehensive and concrete view of miRNA biology than anyone ever expected. Diverse genetic origins and biogenesis pathways leading to functional miRNAs converge on the synthesis of ≈21-nucleotide RNA duplex, almost all of which are processed from long premature sequences in a DICER- and/or DROSHA-dependent manner. Formerly, it was assumed that one mature strand of the duplex is preferentially selected for entry into the silencing complex, and the paired passenger strands (miRNA*) are subjected to degradation. However, given the consolidated evidence of substantial regulatory activity of miRNA* species, currently, this preconception has been overturned. Here, we see the caveat and opportunity toward exogenously manipulating the expression of premature miRNA, leading to simultaneous upregulation or downregulation of dual regulatory strands due to altered expressions. The caveat is the overlooked miRNA* interference while manipulating the expression of a target miRNA at the premature stage, wherein lies the opportunity. If the dual strands of a pre-miRNA function synergistically, the overlooked miRNA* interference may inversely optimize the therapeutic performance. Insightfully, targeting the premature miRNAs may serve as the “one-two punch” against diseases, especially cancers, and this has been discussed in detail in this review.

An Evolutionary Cancer Epigenetic Approach Revealed DNA Hypermethylation of Ultra-Conserved Non-Coding Elements in Squamous Cell Carcinoma of Different Mammalian Species

Background: Ultra-conserved non-coding elements (UCNEs) are genomic sequences that exhibit > 95% sequence identity between humans, mammals, birds, reptiles, and fish. Recent findings reported their functional role in cancer. The aim of this study was to evaluate the DNA methylation modifications of UNCEs in squamous cell carcinoma (SCC) from different mammal species. Methods: Fifty SCCs from 26 humans, 17 cats, 3 dogs, 1 horse, 1 bovine, 1 badger, and 1 porcupine were investigated. Fourteen feline stomatitis and normal samples from 36 healthy human donors, 7 cats, 5 dogs, 5 horses, 2 bovines and 1 badger were collected as normal controls. Bisulfite next generation sequencing evaluated the DNA methylation level from seven UCNEs (uc.160, uc.283, uc.416, uc.339, uc.270, uc.299, and uc.328). Results: 57/59 CpGs were significantly different according to the Kruskal–Wallis test (p < 0.05) comparing normal samples with SCC. A common DNA hypermethylation pattern was observed in SCCs from all the species evaluated in this study, with an increasing trend of hypermethylation starting from normal mucosa, through stomatitis to SCC. Conclusions: Our findings indicate that UCNEs are hypermethylated in human SCC, and this behavior is also conserved among different species of mammals.

Clinical significance of CCNE2 protein and mRNA expression in thyroid cancer tissues

PURPOSE

Thyroid carcinoma (TC) is the most common endocrinal malignancy worldwide. Cyclin E2 (CCNE2), a member of the cyclin family, acts as a regulatory subunit of cyclin-dependent kinases (CDKs). It controls the transition of quiescent cells into the cell cycle, regulates the G1/S transition, promotes DNA replication, and activates CDK2. This study explored the role and potential molecular mechanisms of CCNE2 expression in TC tissues.

MATERIAL/METHODS

Immunohistochemistry was used to evaluate the CCNE2 protein expression levels in TC. High-throughput data on CCNE2 in TC were obtained from RNA sequencing (RNA-seq), microarray, and literature data. The CCNE2 expression levels in TC were comprehensively assessed through an integrated analysis. Analyses of Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPIs) data facilitated the investigation of the relative molecular mechanisms of CCNE2 in TC.

RESULTS

The immunohistochemical experiment showed a significant increase in the expression of CCNE2 in the TC tissues. For 505 TC and 59 non-cancerous samples from RNA-seq data, the area under the curve (AUC) was 0.8016 (95% confidence interval [CI] 0.742-0.8612; p<0.001). With another 14 microarrays, the pool standard mean difference [SMD] was 1.01 (95% CI [0.82-1.19]). The pooled SMD of CCNE2 was 1.12 (95% CI [0.60-1.64]), and the AUC was 0.87 (95% CI [0.84-0.90]) for 1157 TC samples and 366 non-cancerous thyroid samples from all possible sources. Nine hub genes were upregulated in TC.

CONCLUSIONS

A high expression of CCNE2 may lead to carcinogenesis and the development of TC.

Targeting Epigenetic Dependencies in Solid Tumors: Evolutionary Landscape Beyond Germ Layers Origin

Extensive efforts recently witnessed the complexity of cancer biology; however, molecular medicine still lacks the ability to elucidate hidden mechanisms for the maintenance of specific subclasses of rare tumors characterized by the silent onset and a poor prognosis (e.g., ovarian cancer, pancreatic cancer, and glioblastoma). Recent mutational fingerprints of human cancers highlighted genomic alteration occurring on epigenetic modulators. In this scenario, the epigenome dependency of cancer orchestrates a broad range of cellular processes critical for tumorigenesis and tumor progression, possibly mediating escaping mechanisms leading to drug resistance. Indeed, in this review, we discuss the pivotal role of chromatin remodeling in shaping the tumor architecture and modulating tumor fitness in a microenvironment-dependent context. We will also present recent advances in the epigenome targeting, posing a particular emphasis on how this knowledge could be translated into a feasible therapeutic approach to individualize clinical settings and improve patient outcomes.

Downregulation of TMOD1 promotes cell motility and cell proliferation in cervical cancer cells

Tropomodulin-1 (TMOD1) is a key regulator of actin dynamics, which caps the pointed end of actin filaments. TMOD1 has been reported to be involved in several cellular processes, including neurite outgrowth, spine formation and cell migration. Increasing evidence demonstrates that TMOD1 is implicated in several aspects of cancer development. The present study aimed to investigate the role of TMOD1 in cervical cancer. HeLa and CaSki cell lines, derived from human cervical cancer, were used to evaluate the function of TMOD1. Cell motility was measured via a wound-healing assay, with the TMOD1 short hairpin (sh)RNAs transfected cells. Subsequently, cell proliferation was assessed using low serum cell culture condition, while cell cycle distribution was analyzed via flow cytometry. The results demonstrated that downregulated TMOD1 promoted cell motility and proliferation, which is attributed to promotion of G₁/S phase transition in HeLa and CaSki cells. Furthermore, it was indicated that co-expression of shRNA resistant TMOD1 rescued these phenomena. The clinical data demonstrated that high TMOD1 expression is associated with good pathological status in patients with cervical cancer. Overall, the results of the present study indicated that TMOD1 may act as a tumor suppressor in cervical cancer, whereby its downregulated expression was demonstrated to have direct effects on cell motility and cell proliferation. These results provide new evidence for the prognostic prediction of cervical cancer, which may serve as a promising therapeutic strategy for patients with cervical cancer.

Circular RNA ATXN7 promotes the development of gastric cancer through sponging miR-4319 and regulating ENTPD4

Background

Circular RNAs (circRNAs) which are shown as a class of RNAs exhibit the importance in the regulation of gene expression and the development of biological process. However, the expression profile and molecular mechanism of circRNA ATXN7 (circATXN7) is still mostly uncertain in gastric cancer (GC).

Methods

qRT-PCR analysis was performed to detect the expression of circATXN7, miR-4319 and ENTPD4 in GC tissues and cells. CCK-8, colony formation, EdU, flow cytometry, TUNEL and transwell assays were conducted to assess the effect of circATXN7 or miR-4319 on cell proliferation, apoptosis and invasion. In vivo assays were utilized to further analyze the function of circATXN7 on the tumorigenesis and progression of GC. The interaction between miR-4319 and circATXN7 (or ENTPD4) was verified using luciferase reporter and RNA pull-down assays.

Results

The results showed an upregulated circATXN7 expression in GC tissues and cell lines. Besides, silenced circATXN7 hampered the proliferation and invasion as well as promoted the apoptosis in GC cells. Moreover, low expression of miR-4319 was found in GC. It was determined that circATXN7 acted as a sponge for miR-4319 and had a negative association with miR-4319. We also found that miR-4319 upregulation restrained GC cell proliferation and migration whereas enhanced apoptosis. Subsequently, ENTPD4, the target gene of miR-4319, was found overexpressed in GC. Additionally, it was negatively correlated with miR-4319 whereas positively associated with circATXN7. In vivo experiments, circATXN7 silence was confirmed to inhibit GC tumor growth.

Conclusions

CircATXN7 promoted GC development through sponging miR-4319 and regulating ENTPD4, which identified circATXN7 as a new biomarker in GC.

LncRNA DLEU2 accelerates the tumorigenesis and invasion of non-small cell lung cancer by sponging miR-30a-5p

Long non‐coding RNAs (lncRNAs) have been reported to participate in the pathogenesis of non–small cell lung cancer (NSCLC). However, how lncRNA deleted in lymphocytic leukaemia 2 (DLEU2) contributes to NSCLC remains undocumented. The clinical significance of lncRNA DLEU2 and miR‐30a‐5p expression in NSCLC was analysed by using fluorescence in situ hybridization and TCGA cohorts. Gain‐ and loss‐of‐function experiments as well as a NSCLC tumour model were executed to determine the role of lncRNA DLEU2 in NSCLC. DLEU2‐sponged miR‐30a‐5p was verified by luciferase reporter, and RIP assays. Herein, the expression of lncRNA DLEU2 was elevated in NSCLC tissues, and its high expression or low expression of miR‐30a‐5p acted as an independent prognostic factor of poor survival and tumour recurrence in NSCLC. Silencing of lncRNA DLEU2 repressed the tumorigenesis and invasive potential of NSCLC, whereas re‐expression of lncRNA DLEU2 showed the opposite effects. Furthermore, lncRNA DLEU2 harboured a negative correlation with miR‐30a‐5p expression in NSCLC tissues and acted as a sponge of miR‐30a‐5p, which reversed the tumour‐promoting effects of lncRNA DLEU2 by targeting putative homeodomain transcription factor 2 in NSCLC. Altogether, lncRNA DLEU2 promoted the tumorigenesis and invasion of NSCLC by sponging miR‐30a‐5p.

Decrypting noncoding RNA interactions, structures, and functional networks

The world of noncoding RNAs (ncRNAs) is composed of an enormous and growing number of transcripts, ranging in length from tens of bases to tens of kilobases, involved in all biological processes and altered in expression and/or function in many types of human disorders. The premise of this review is the concept that ncRNAs, like many large proteins, have a multidomain architecture that organizes them spatially and functionally. As ncRNAs are beginning to be imprecisely classified into functional families, we review here how their structural properties might inform their functions with focus on structural architecture-function relationships. We will describe the properties of "interactor elements" (IEs) involved in direct physical interaction with nucleic acids, proteins, or lipids and of "structural elements" (SEs) directing their wiring within the "ncRNA interactor networks" through the emergence of secondary and/or tertiary structures. We suggest that spectrums of "letters" (ncRNA elements) are assembled into "words" (ncRNA domains) that are further organized into "phrases" (complete ncRNA structures) with functional meaning (signaling output) through complex "sentences" (the ncRNA interactor networks). This semiotic analogy can guide the exploitation of ncRNAs as new therapeutic targets through the development of IE-blockers and/or SE-lockers that will change the interactor partners' spectrum of proteins, RNAs, DNAs, or lipids and consequently influence disease phenotypes.

The Transcribed-Ultra Conserved Regions: Novel Non-Coding RNA Players in Neuroblastoma Progression

The Transcribed-Ultra Conserved Regions (T-UCRs) are a class of novel non-coding RNAs that arise from the dark matter of the genome. T-UCRs are highly conserved between mouse, rat, and human genomes, which might indicate a definitive role for these elements in health and disease. The growing body of evidence suggests that T-UCRs contribute to oncogenic pathways. Neuroblastoma is a type of childhood cancer that is challenging to treat. The role of non-coding RNAs in the pathogenesis of neuroblastoma, in particular for cancer development, progression, and therapy resistance, has been documented. Exosmic non-coding RNAs are also involved in shaping the biology of the tumor microenvironment in neuroblastoma. In recent years, the involvement of T-UCRs in a wide variety of pathways in neuroblastoma has been discovered. Here, we present an overview of the involvement of T-UCRs in various cellular pathways, such as DNA damage response, proliferation, chemotherapy response, MYCN (v-myc myelocytomatosis viral related oncogene, neuroblastoma derived (avian)) amplification, gene copy number, and immune response, as well as correlate it to patient survival in neuroblastoma.

Clinical utility of circulating non-coding RNAs - an update

Over the past decade, the amount of research and the number of publications on associations between circulating small and long non-coding RNAs (ncRNAs) and cancer have grown exponentially. Particular focus has been placed on the development of diagnostic and prognostic biomarkers to enable efficient patient management - from early detection of cancer to monitoring for disease recurrence or progression after treatment. Owing to their high abundance and stability, circulating ncRNAs have potential utility as non-invasive, blood-based biomarkers that can provide information on tumour biology and the effects of treatments, such as targeted therapies and immunotherapies. Increasing evidence highlights the roles of ncRNAs in cell-to-cell communication, with a number of ncRNAs having the capacity to regulate gene expression outside of the cell of origin through extracellular vesicle-mediated transfer to recipient cells, with implications for cancer progression and therapy resistance. Moreover, 'foreign' microRNAs (miRNAs) encoded by non-human genomes (so-called xeno-miRNAs), such as viral miRNAs, have been shown to be present in human body fluids and can be used as biomarkers. Herein, we review the latest developments in the use of circulating ncRNAs as diagnostic and prognostic biomarkers and discuss their roles in cell-to-cell communication in the context of cancer. We provide a compendium of miRNAs and long ncRNAs that have been reported in the literature to be present in human body fluids and that have the potential to be used as diagnostic and prognostic cancer biomarkers.

The Function of Non-Coding RNAs in Lung Cancer Tumorigenesis

Lung cancer is the most prevalent and deadliest cancer worldwide. A significant part of lung cancer studies is dedicated to the expression alterations of non-coding RNAs. The non-coding RNAs are transcripts that cannot be translated into proteins. While the study of microRNAs and siRNAs in lung cancer received a lot of attention over the last decade, highly efficient therapeutic option or the diagnostic methods based on non-coding RNAs are still lacking. Because of this, it is of utmost importance to direct future research on lung cancer towards analyzing other RNA types for which the currently available data indicates that are essential at modulating lung tumorigenesis. Through our review of studies on this subject, we identify the following non-coding RNAs as tumor suppressors: ts-46, ts-47, ts-101, ts-53, ts-3676, ts-4521 (tRNA fragments), SNORD116-26, HBII-420, SNORD15A, SNORA42 (snoRNAs), piRNA-like-163, piR-35127, the piR-46545 (piRNAs), CHIAP2, LOC100420907, RPL13AP17 (pseudogenes), and uc.454 (T-UCR). We also found non-coding RNAs with tumor-promoting function: tRF-Leu-CAG, tRNA-Leu, tRNA-Val (tRNA fragments), circ-RAD23B, circRNA 100146, circPVT1, circFGFR3, circ_0004015, circPUM1, circFLI1, circABCB10, circHIPK3 (circRNAs), SNORA42, SNORA3, SNORD46, SNORA21, SNORD28, SNORA47, SNORD66, SNORA68, SNORA78 (snoRNAs), piR-65, piR-34871, piR-52200, piR651 (piRNAs), hY4 5’ fragments (YRNAs), FAM83A-AS1, WRAP53, NKX2-1-AS1 (NATs), DUXAP8, SFTA1P (pseudogene transcripts), uc.338, uc.339 (T-UCRs), and hTERC.

Circular RNA ATXN7 is upregulated in non-small cell lung cancer and promotes disease progression

Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that is generated from back-splicing, and is characterized by a covalent closed loop without 3′ and 5′ ends. Recently, the biological function of circRNAs has received increasing attention; however, studies on circRNAs in non-small cell lung cancer (NSCLC) have rarely been reported. In the present study, the expression profiles of circRNAs in NSCLC were investigated, and the association between the circular RNA ATXN7 (circATXN7) expression level and clinicopathological characteristics of patients with NSCLC was assessed. In addition, the effects of circATXN7 on cell proliferation and invasion were examined. The results revealed that circATXN7 was upregulated in 45 NSCLC tissues compared with its expression in non-tumor tissues. However, there was no marked difference between the expression level of circATXN7 and the majority of the examined clinicopathological characteristics. It was also observed that the survival time of patients with high circATXN7 levels was shorter compared with that of patients with low circATXN7 levels, although the difference was not statistically significant (P>0.05). Furthermore, silencing of circATXN7 by small interfering RNA inhibited the proliferation and invasion of NSCLC cells in vitro. Taken together, the present study was the first to identify that circATXN7 was upregulated in NSCLC tumor tissues. Furthermore, the downregulation of circATXN7 markedly inhibited the proliferation and invasion abilities of NSCLC cells.

The Non-Coding RNA Journal Club: Highlights on Recent Papers-6

We are delighted to share with you our sixth Journal Club and highlight some of the most interesting papers published recently [...].

Regulation of Intestinal Epithelial Barrier Function by Long Noncoding RNA uc.173 through Interaction with MicroRNA 29b

The mammalian intestinal epithelium establishes a selectively permeable barrier that supports nutrient absorption and prevents intrusion by noxious luminal substances and microbiota. The effectiveness and integrity of the barrier function are tightly regulated via well-controlled mechanisms. Long noncoding RNAs transcribed from ultraconserved regions (T-UCRs) control diverse cellular processes, but their roles in the regulation of gut permeability remain largely unknown. Here we report that the T-UCR uc.173 enhances intestinal epithelial barrier function by antagonizing microRNA 29b (miR-29b). Decreasing the levels of uc.173 by gene silencing led to dysfunction of the intestinal epithelial barrier in cultured cells and increased the vulnerability of the gut barrier to septic stress in mice. uc.173 specifically stimulated translation of the tight junction (TJ) claudin-1 (CLDN1) by associating with miR-29b rather than by binding directly to CLDN1 mRNA. uc.173 acted as a natural decoy RNA for miR-29b, which interacts with CLDN1 mRNA via the 3' untranslated region and represses its translation. Ectopically expressed uc.173 abolished the association of miR-29b with CLDN1 mRNA and restored claudin-1 expression to normal levels in cells overexpressing miR-29b, thus rescuing the barrier function. These results highlight a novel function of uc.173 in controlling gut permeability and define a mechanism by which uc.173 stimulates claudin-1 translation, by decreasing the availability of miR-29b to CLDN1 mRNA.