circRNA: A New Biomarker and Therapeutic Target for Esophageal Cancer

Dysregulation of the circ-Hdac4/miR-30c/RBPJ axis in decidua impairs placental function in preeclampsia

Embryo implantation relies on complex mother-fetus interactions. Abnormal decidualization can cause various pregnancy complications such as placental abnormalities, preeclampsia, and fetal growth restriction. circRNAs play a key role in various cellular processes. This study focuses on the role of circ-Hdac4, a circRNA derived from the Hdac4 gene, in decidualization and placental function. Mouse models revealed a spatiotemporally regulated expression of circ-Hdac4 in the endometrium during early pregnancy, with enhanced expression surrounding implantation sites. In vitro and in vivo assays confirmed that circ-Hdac4 is crucial for stromal cell decidualization, as its knockdown resulted in reduced expression of decidualization markers and disrupted endometrial architecture. Furthermore, we found that circ-Hdac4 functions as a microRNA sponge for miR-30c, which negatively regulates RBPJ, a critical protein for decidual remodeling. Proteomic analysis revealed that RBPJ was downregulated upon circ-Hdac4 silencing, and we validated the direct interaction between miR-30c and RBPJ using luciferase reporter assays. A mouse preeclampsia model showed that downregulation of circ-Hdac4 during decidualization exacerbated preeclampsia-related phenotypes, including reduced fetal counts, weights, and placental weights. In addition, we observed decreased expression of circ-Hdac4 and RBPJ in the decidual surface of placental tissues from preeclampsia patients, further supporting our findings in the mouse model. Collectively, our study provides evidence that circ-Hdac4 regulates decidualization through the miR-30c-RBPJ axis and that its abnormal expression during decidualization contributes to placental dysfunction in preeclampsia. This research offers novel insights into the molecular mechanisms underlying pregnancy complications and potential therapeutic targets for their prevention and treatment.

CircPRKCA facilitates esophageal squamous cell carcinoma metastasis via m5C-dependent CSF2 mRNA stabilization

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a serious invasive malignancy with an ambiguous etiology. Evidence indicates that circular RNA (circRNA) is significantly involved in the regulatory processes associated with cancer development. Nevertheless, the specific molecular mechanisms through which circRNA facilitates the progression of ESCC are still largely undefined.

METHODS

Here, we identified that the expression of hsa_circ_0007580 (designated circPRKCA) was markedly elevated in ESCC. Fluorescence in situ hybridization (FISH) was conducted to verify the expression, intracellular localization, and potential prognostic value of circPRKCA based on the tissue microarray. Gain- and loss-of-function assays were employed to investigate the effects of circPRKCA both in vitro and in vivo. RNA pull-down and mass spectrometry (MS) were performed to identify the proteins bound to circPRKCA. mRNA sequencing was conducted to screen the downstream target genes of circPRKCA. Furthermore, immunoprecipitation and methylated RNA immunoprecipitation (MeRIP) analysis were used to explore the regulatory mechanisms.

RESULTS

We found that circPRKCA exhibited significant upregulation in ESCC tissues and correlated with unfavorable prognostic outcomes. Biological function experiments further confirmed that circPRKCA enhances the capabilities of migration, invasion, and angiogenesis in ESCC. Mechanistically, circPRKCA engages in interaction with Y-box binding protein 1 (YBX1) within the cytoplasmic milieu, consequently preventing the ubiquitination-mediated degradation of YBX1. Increased concentrations of YBX1 increase the stability of granulocyte-macrophage colony-stimulating factor (CSF2) mRNA in a 5-methylcytosine (m5C)-dependent manner. This process facilitates metastasis in ESCC.

CONCLUSION

In this research, we identified a correlation between circPRKCA and unfavorable prognoses in patients with ESCC. It is instrumental in the metastatic progression of ESCC via the YBX1/CSF2 signaling pathway. Consequently, targeting circPRKCA may represent a promising therapeutic strategy for ESCC.

miR-542-3p/PIK3R1 axis is involved in hsa_circ_0087104-mediated inhibition of esophageal squamous cell carcinoma metastasis

Esophageal squamous cell carcinoma (ESCC), the most predominant subtype of esophageal cancer, is notorious for its high lymph node metastatic potential and poor prognosis. Growing evidence has demonstrated crucial function of circRNAs in human malignancies. However, the knowledge of circRNAs in lymph node metastasis of ESCC is still inadequate. In this study, a series of bioinformatic analyses and experimental validation were performed. By performing differential expression analysis and selection for GEO dataset GSE150476, a total of 8 circRNAs associated with lymph node metastasis of ESCC were identified. Expression analysis confirmed their low expression in ESCC tissues (relative to normal tissues) or metastatic sites (relative to primary sites). By combination of binding miRNAs from CSCD and starBase databases, six potential miRNAs (miR-532-5p, miR-2681-5p, miR-670-5p, miR-1252-5p, miR-382-3p and miR-542-3p) were predicted and a circRNA-miRNA regulatory network was constructed. Next, 695 target genes were predicted to bind to the 6 miRNAs. After conducting protein-protein interaction (PPI) network analysis, hub gene identification and expression analysis, a hub gene PIK3R1 was identified as the most potential downstream target gene of hsa_circ_0087104/miR-542-3p in ESCC. Hsa_circ_0087104 and PIK3R1 were decreased while miR-542-3p was increased in ESCC cells compared with normal esophageal epithelial cell line. Luciferase reporter and MS2-RIP assays confirmed the direct bind of miR-542-3p to hsa_circ_0087104 or PIK3R1. Hsa_circ_0087104 increased PIK3R1 expression but ectopic expression of miR-542-3p reversed hsa_circ_0087104-mediated PIK3R1 overexpression in ESCC. Overexpression of hsa_circ_0087104 suppressed in vitro migration and invasion of ESCC cells and this suppressive effect could be weakened by upregulation of miR-542-3p. Collectively, the current findings elucidated a potential hsa_circ_0087104/miR-542-3p/PIK3R1 axis that might be involved in suppression of lymph node metastasis of ESCC.

Non-coding RNAs and exosomal non-coding RNAs in lung cancer: insights into their functions

Lung cancer is the second most common form of cancer worldwide Research points to the pivotal role of non-coding RNAs (ncRNAs) in controlling and managing the pathology by controlling essential pathways. ncRNAs have all been identified as being either up- or downregulated among individuals suffering from lung cancer thus hinting that they may play a role in either promoting or suppressing the spread of the disease. Several ncRNAs could be effective non-invasive biomarkers to diagnose or even serve as effective treatment options for those with lung cancer, and several molecules have emerged as potential targets of interest. Given that ncRNAs are contained in exosomes and are implicated in the development and progression of the malady. Herein, we have summarized the role of ncRNAs in lung cancer. Moreover, we highlight the role of exosomal ncRNAs in lung cancer.

Non-coding RNAs in lung cancer: molecular mechanisms and clinical applications

Lung cancer (LC) is a heterogeneous disease with high malignant degree, rapid growth, and early metastasis. The clinical outcomes of LC patients are generally poor due to the insufficient elucidation of pathological mechanisms, low efficiency of detection and assessment methods, and lack of individualized therapeutic strategies. Non-coding RNAs (ncRNAs), including microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA), are endogenous regulators that are widely involved in the modulation of almost all aspects of life activities, from organogenesis and aging to immunity and cancer. They commonly play vital roles in various biological processes by regulating gene expression via their interactions with DNA, RNA, or protein. An increasing amount of studies have demonstrated that ncRNAs are closely correlated with the initiation and development of LC. Their dysregulation promotes the progression of LC via distinct mechanisms, such as influencing protein activity, activating oncogenic signaling pathways, or altering specific gene expression. Furthermore, some ncRNAs present certain clinical values as biomarker candidates and therapeutic targets for LC patients. A complete understanding of their mechanisms in LC progression may be highly beneficial to developing ncRNA-based therapeutics for LC patients. This review mainly focuses on the intricate mechanisms of miRNA, lncRNA, and circRNA involved in LC progression and discuss their underlying applications in LC treatment.

CircRNA mannosidase alpha class 1A member 2 promotes esophageal squamous cell carcinoma progression by regulating C-C chemokine ligand 5

Esophageal squamous cell carcinoma (ESCC) is a common malignancy with high morbidity and mortality. Although circular RNAs (circRNAs) play important roles in various cancers including ESCC, the role of the circRNA mannosidase alpha class 1A member 2 (circMAN1A2) in ESCC has been rarely studied. This study aimed to explore the role of circMAN1A2 in ESCC. CircMAN1A2 expression in ESCC tissues and cells was evaluated, and the relationship between circMAN1A2 expression and prognosis in patients with ESCC was analyzed. C-C chemokine ligand 5 (CCL5) was found to be a downstream target of circMAN1A2 by analysing the Agilent Microarray. Next, we performed in vitro and in vivo xenotransplantation assays to explore the role of circMAN1A2 in ESCC. We observed that high circMAN1A2 expression is associated with poor prognosis in patients with ESCC. Suppression of circMAN1A2 expression inhibits the proliferation, migration, and invasiveness of ESCC via regulating CCL5. Our results suggest that circMAN1A2 can promote the progression of ESCC by regulating CCL5. Thus, circMAN1A2 might be a novel diagnostic biomarker of ESCC, and targeting circMAN1A2 using inhibitors could be a potential therapeutic strategy to treat ESCC.

CircZXDC Promotes Vascular Smooth Muscle Cell Transdifferentiation via Regulating miRNA-125a-3p/ABCC6 in Moyamoya Disease

Moyamoya disease (MMD) is an occlusive, chronic cerebrovascular disease affected by genetic mutation and the immune response. Furthermore, vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) participate in the neointima of MMD, but the etiology and pathophysiological changes in MMD vessels remain largely unknown. Therefore, we established the circZXDC (ZXD family zinc finger C)-miR-125a-3p-ABCC6 (ATP-binding cassette subfamily C member 6) axis from public datasets and online tools based on "sponge-like" interaction mechanisms to investigate its possible role in VSMCs. The results from a series of in vitro experiments, such as dual luciferase reporter assays, cell transfection, CCK-8 assays, Transwell assays, and Western blotting, indicate a higher level of circZXDC in the MMD plasma, especially in those MMD patients with the RNF213 mutation. Moreover, circZXDC overexpression results in a VSMC phenotype switching toward a synthetic status, with increased proliferation and migration activity. CircZXDC sponges miR-125a-3p to increase ABCC6 expression, which induces ERS (endoplasmic reticulum stress), and subsequently regulates VSMC transdifferentiation from the contractive phenotype to the synthetic phenotype, contributing to the intima thickness of MMD vessels. Our findings provide insight into the pathophysiological mechanisms of MMD and indicate that the circZXDC-miR-125a-3p-ABCC6 axis plays a pivotal role in the progression of MMD. Furthermore, circZXDC might be a diagnostic biomarker and an ABCC6-specific inhibitor and has the potential to become a promising therapeutic option for MMD.