Circular RNA hsa_circ_0006117 Facilitates Pancreatic Cancer Progression by Regulating the miR-96-5p/KRAS/MAPK Signaling Pathway

Exploring the prognostic value of circular RNAs in pancreatic ductal adenocarcinoma using genome-wide expression profiling

BACKGROUND/OBJECTIVES

Median survival of pancreatic ductal adenocarcinoma (PDAC) is around eight months and new prognostic tools are needed. Circular RNAs (circRNAs) have gained interest in different types of cancer. However, only a few studies have evaluated their potential in PDAC. We aimed to identify the most differentially expressed circRNAs in PDAC compared to controls and to explore their potential as prognostic markers.

METHODS

Using frozen specimens with PDAC and controls, we performed RNA sequencing and identified 20,440 unique circRNAs. A custom code set of capture- and reporter probes for NanoString nCounter analysis was designed to target 152 circRNAs, based on abundancy, differential expression and a literature study. Expression of these 152 circRNAs was examined in 108 formalin-fixed and paraffin-embedded surgical PDAC specimens and controls. The spatial expression of one of the most promising candidates, ciRS-7 (hsa_circ_0001946), was evaluated by chromogenic in situ hybridization (CISH) using multi-punch tissue microarrays (TMAs) and digital imaging analysis.

RESULTS

Based on circRNA expression profiles, we identified different PDAC subclusters. The 30 most differentially expressed circRNAs showed log2 fold changes from -3.43 to 0.94, where circNRIP1 (hsa_circ_0004771), circMBOAT2 (hsa_circ_0007334) and circRUNX1 (hsa_circ_0002360) held significant prognostic value in multivariate analysis. CiRS-7 was absent in PDAC cells but highly expressed in the tumor microenvironment.

CONCLUSIONS

We identified several new circRNAs with biomarker potential in surgically treated PDAC, three of which showed an independent prognostic value. We also found that ciRS-7 is absent in cancer cells but abundant in tumor microenvironment and may hold potential as marker of activated stroma.

Long non-coding RNA Small Nucleolar RNA Host Gene 4 ameliorates cigarette smoke-induced proliferation, apoptosis, inflammation, and airway remodeling in alveolar epithelial cells through the modulation of the mitogen-activated protein kinase signaling pathway via the microRNA-409-3p/Four and a Half LIM Domains 1 axis

The long non-coding RNA (lncRNA) Small Nucleolar RNA Host Gene 4 (SNHG4) has been demonstrated to be significantly downregulated in various inflammatory conditions, yet its role in chronic obstructive pulmonary disease (COPD) remains elusive. This study aims to elucidate the biological function of SNHG4 in COPD and to unveil its potential molecular targets. Our findings reveal that both SNHG4 and Four and a Half LIM Domains 1 (FHL1) were markedly downregulated in COPD, whereas microRNA-409-3p (miR-409-3p) was upregulated. Importantly, SNHG4 exhibited a negative correlation with inflammatory markers in patients with COPD, but a positive correlation with forced expiratory volume in 1s percentage (FEV1%). SNHG4 distinguished COPD patients from non-smokers with high sensitivity, specificity, and accuracy. Overexpression of SNHG4 ameliorated cigarette smoke extract (CSE)-mediated inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE bronchial epithelial cells. These beneficial effects of SNHG4 overexpression were reversed by the overexpression of miR-409-3p or the silencing of FHL1. Mechanistically, SNHG4 competitively bound to miR-409-3p, mediating the expression of FHL1, and consequently improving inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE cells. Additionally, SNHG4 regulated the miR-409-3p/FHL1 axis to inhibit the activation of the mitogen-activated protein kinase (MAPK) pathway induced by CSE. In a murine model of COPD, knockdown of SNHG4 exacerbated CSE-induced pulmonary inflammation, apoptosis, and oxidative stress. In summary, our data affirm that SNHG4 mitigates pulmonary inflammation, apoptosis, and oxidative damage mediated by COPD through the regulation of the miR-409-3p/FHL1 axis.

Role of circular RNAs and gut microbiome in gastrointestinal cancers and therapeutic targets

Gastrointestinal cancers are a huge worldwide health concern, which includes a wide variety of digestive tract cancers. Circular RNAs (circRNAs), a kind of non-coding RNA (ncRNAs), are a family of single-stranded, covalently closed RNAs that have become recognized as crucial gene expression regulators, having an impact on several cellular functions in cancer biology. The gut microbiome, which consists of several different bacteria, actively contributes to the regulation of host immunity, inflammation, and metabolism. CircRNAs and the gut microbiome interact significantly to greatly affect the growth of GI cancer. Several studies focus on the complex functions of circRNAs and the gut microbiota in GI cancers, including esophageal cancer, colorectal cancer, gastric cancer, hepatocellular cancer, and pancreatic cancer. It also emphasizes how changed circRNA expression profiles and gut microbiota affect pathways connected to malignancy as well as how circRNAs affect hallmarks of gastrointestinal cancers. Furthermore, circRNAs and gut microbiota have been recommended as biological markers for therapeutic targets as well as diagnostic and prognostic purposes. Targeting circRNAs and the gut microbiota for the treatment of gastrointestinal cancers is also being continued to study. Despite significant initiatives, the connection between circRNAs and the gut microbiota and the emergence of gastrointestinal cancers remains poorly understood. In this study, we will go over the most recent studies to emphasize the key roles of circRNAs and gut microbiota in gastrointestinal cancer progression and therapeutic options. In order to create effective therapies and plan for the future gastrointestinal therapy, it is important to comprehend the functions and mechanisms of circRNAs and the gut microbiota.

Roles of circular RNAs in the pathogenesis and treatment of pancreatic cancer

Circular RNAs are single-stranded RNAs with a covalently closed structure formed by the process of back-splicing. Aberrant expression of circular RNAs contributes to the pathogenesis of a wide range of cancers. Pancreatic cancer is one of the most lethal cancers due to diagnostic difficulties and limited therapeutic options. Circular RNAs are emerging as novel diagnostic biomarkers and therapeutic targets for pancreatic cancer. Moreover, recent advances in the therapeutic application of engineered circular RNAs have provided a promising approach to overcoming pancreatic cancer. This review discusses the roles of circular RNAs in the pathogenesis of pancreatic cancer and in potential treatment applications and their usefulness as diagnostic biomarkers.

Spatiotemporal Regulation of Circular RNA Expression during Liver Development of Chinese Indigenous Ningxiang Pigs

BACKGROUND

There have been many studies on the relationship between circRNAs and fat deposition. Although the liver is a central organ for fat metabolism, there are few reports on the relationship between circRNAs in the liver and fat deposition.

METHODS

In this study, we systematically analyzed circular RNAs in the liver of Ningxiang pigs, at four time points after birth (30 days, 90 days, 150 days and 210 days).

RESULTS

A total of 3705 circRNAs were coexpressed in four time periods were found, and KEGG analysis showed that the significantly upregulated pathways were mainly enriched in lipid metabolism and amino acid metabolism, while significantly downregulated pathways were mainly related to signal transduction, such as ECM-receptor interaction, MAPK signaling pathway, etc. Short time-series expression miner (STEM) analysis showed multiple model spectra that were significantly enriched over time in the liver. By constructing a competing endogenous RNA (ceRNA) regulatory network, 9187 pairs of networks related to the change in development time were screened.

CONCLUSIONS

The expression profiles of circRNAs in Ningxiang pig liver were revealed at different development periods, and it was determined that there is differential coexpression. Through enrichment analysis of these circRNAs, it was revealed that host genes were involved in metabolism-related signaling pathways and fatty acid anabolism. Through STEM analysis, many circRNAs involved in fat metabolism, transport, and deposition pathways were screened, and the first circRNA-miRNA-mRNA regulation network map in Ningxiang pig liver was constructed. The highly expressed circRNAs related to fat deposition were verified and were consistent with RNA-Seq results.

Long Noncoding RNA 00472: A Novel Biomarker in Human Diseases

Long non-coding RNAs (lncRNAs) play important roles in human diseases. They control gene expression levels and influence various biological processes through multiple mechanisms. Functional abnormalities in lncRNAs are strongly associated with occurrence and development of various diseases. LINC00472, which is located on chromosome 6q13, is involved in several human diseases, particularly cancers of the breast, lung, liver, osteosarcoma, bladder, colorectal, ovarian, pancreatic and stomach. Importantly, LINC00472 can be used as a biomarker for breast cancer cell sensitivity to chemotherapeutic regimens, including doxorubicin. LINC00472 is regulated by microRNAs and several signaling pathways. However, the significance of LINC00472 in human diseases has not been clearly established. In this review, we elucidate on the significance of LINC00472 in various human diseases, indicating that LINC00472 may be a diagnostic, prognostic as well as therapeutic target for these diseases.