Circ_0119872 promotes uveal melanoma development by regulating the miR-622/G3BP1 axis and downstream signalling pathways

ADAM10 promotes uveal melanoma development by regulating the Wnt/β-catenin pathway

BACKGROUND

Uveal melanoma (UVM) seriously affects people's health and quality of life. Here, the mechanism of a disintegrin and metallopeptidase domain 10 (ADAM10) was elucidated in UVM.

METHODS

The clinical prognosis and potential biological function of ADAM10 gene in UVM patients were assessed using a series of bioinformatics methods. RT-qPCR and Western blot assay were employed to detect genes expression. Cell apoptosis and viability were examined by flow cytometry, clone formation and CCK-8 assays. The migrated and invasive abilities were analyzed by wound healing and transwell assays. Tumor growth was performed in Xenograft mouse model.

RESULTS

We found that ADAM10 expression was significantly associated with poor prognosis of UVM patients, and its prognostic significance for UVM patients was determined by distinct clinical characteristics. In vitro, ADAM10 expression was upregulated in MUM-2B and C918 UVM cell lines. More importantly, ADAM10 downregulation discouraged cell viability, metastasis but triggered apoptosis of UVM cells. Moreover, ADAM10 upregulation can promote the tumor growth of UVM in vivo. Mechanically, ADAM10 downregulation blocked the Wnt/β-catenin pathway in UVM.

CONCLUSION

Upregulation of ADAM10 stimulates the malignant behaviors of UVM through activating the Wnt/β-catenin pathway.

CircSSR1 regulates pyroptosis of pulmonary artery smooth muscle cells through parental protein SSR1 mediating endoplasmic reticulum stress

INTRODUCTION

Pyroptosis, inflammatory necrosis of cells, is a programmed cell death involved in the pathological process of diseases. Endoplasmic reticulum stress (ERS), as a protective stress response of cell, decreases the unfold protein concentration to inhibit the unfold protein agglutination. Whereas the relationship between endoplasmic reticulum stress and pyroptosis in pulmonary hypertension (PH) remain unknown. Previous evident indicated that circular RNA (circRNA) can participate in several biological process, including cell pyroptosis. However, the mechanism of circRNA regulate pyroptosis of pulmonary artery smooth muscle cells through endoplasmic reticulum stress still unclear. Here, we proved that circSSR1 was down-regulate expression during hypoxia in pulmonary artery smooth muscle cells, and over-expression of circSSR1 inhibit pyroptosis both in vitro and in vivo under hypoxic. Our experiments have indicated that circSSR1 could promote host gene SSR1 translation via m6A to activate ERS leading to pulmonary artery smooth muscle cell pyroptosis. In addition, our results showed that G3BP1 as upstream regulator mediate the expression of circSSR1 under hypoxia. These results highlight a new regulatory mechanism for pyroptosis and provide a potential therapy target for pulmonary hypertension.

METHODS

RNA-FISH and qRT-PCR were showed the location of circSSR1 and expression change. RNA pull-down and RIP verify the circSSR1 combine with YTHDF1. Western blotting, PI staining and LDH release were used to explore the role of circSSR1 in PASMCs pyroptosis.

RESULTS

CircSSR1 was markedly downregulated in hypoxic PASMCs. Knockdown CircSSR1 inhibited hypoxia induced PASMCs pyroptosis in vivo and in vitro. Mechanistically, circSSR1 combine with YTHDF1 to promote SSR1 protein translation rely on m6A, activating pyroptosis via endoplasmic reticulum stress. Furthermore, G3BP1 induce circSSR1 degradation under hypoxic.

CONCLUSION

Our findings clarify the role of circSSR1 up-regulated parental protein SSR1 expression mediate endoplasmic reticulum stress leading to pyroptosis in PASMCs, ultimately promoting the development of pulmonary hypertension.

Exploring the oncogenic potential of circSOD2 in clear cell renal cell carcinoma: a novel positive feedback loop

BACKGROUND

Existing studies have found that circular RNAs (circRNAs) act as sponges for micro RNAs (miRNAs) to control downstream genes. However, the specific functionalities and mechanisms of circRNAs in human clear cell renal cell carcinoma (ccRCC) have yet to be thoroughly investigated.

METHODS

Patient cohorts from online databases were used to screen candidate circRNAs, while another cohort from our hospital was obtained for validation. CircSOD2 was identified as a potential oncogenic target, and its relevant characteristics were investigated during ccRCC progression through various assays. A positive feedback loop containing downstream miRNA and its target gene were identified using bioinformatics and validated by luciferase reporter assays, RNA pull-down, and high-throughput sequencing.

RESULTS

CircSOD2 expression was elevated in tumor samples and significantly correlated with overall survival (OS) and the tumor stage of ccRCC patients, which appeared in the enhanced proliferation, invasion, and migration of tumor cells. Through competitive binding to circSOD2, miR-532-3p can promote the expression of PAX5 and the progression of ccRCC, and such regulation can be salvaged by miR-532-3p inhibitor.

CONCLUSION

A novel positive feedback loop, PAX5/circSOD2/miR-532-3p/PAX5 was identified in the study, indicating that the loop may play an important role in the diagnosis and prognostic prediction in ccRCC patients.

Recent Advances in Molecular and Genetic Research on Uveal Melanoma

Uveal melanoma (UM), a distinct subtype of melanoma, presents unique challenges in its clinical management due to its complex molecular landscape and tendency for liver metastasis. This review highlights recent advancements in understanding the molecular pathogenesis, genetic alterations, and immune microenvironment of UM, with a focus on pivotal genes, such as GNAQ/11, BAP1, and CYSLTR2, and delves into the distinctive genetic and chromosomal classifications of UM, emphasizing the role of mutations and chromosomal rearrangements in disease progression and metastatic risk. Novel diagnostic biomarkers, including circulating tumor cells, DNA and extracellular vesicles, are discussed, offering potential non-invasive approaches for early detection and monitoring. It also explores emerging prognostic markers and their implications for patient stratification and personalized treatment strategies. Therapeutic approaches, including histone deacetylase inhibitors, MAPK pathway inhibitors, and emerging trends and concepts like CAR T-cell therapy, are evaluated for their efficacy in UM treatment. This review identifies challenges in UM research, such as the limited treatment options for metastatic UM and the need for improved prognostic tools, and suggests future directions, including the discovery of novel therapeutic targets, immunotherapeutic strategies, and advanced drug delivery systems. The review concludes by emphasizing the importance of continued research and innovation in addressing the unique challenges of UM to improve patient outcomes and develop more effective treatment strategies.

Circ_0053943 complexed with IGF2BP3 drives uveal melanoma progression via regulating N6-methyladenosine modification of Epidermal growth factor receptor

Numerous studies have characterized the critical role of circular RNAs (circRNAs) as regulatory factors in the progression of multiple cancers. However, the biological functions of circRNAs and their underlying molecular mechanisms in the progression of uveal melanoma (UM) remain enigmatic. In this study, we identified a novel circRNA, circ_0053943, through re-analysis of UM microarray data and quantitative RT-PCR. Circ_0053943 was found to be upregulated in UM and to promote the proliferation and metastatic ability of UM cells in both in vitro and in vivo settings. Mechanistically, circ_0053943 was observed to bind to the KH1 and KH2 domains of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), thereby enhancing the function of IGF2BP3 by stabilizing its target mRNA. RNA sequencing assays identified epidermal growth factor receptor (EGFR) as a target gene of circ_0053943 and IGF2BP3 at the transcriptional level. Rescue assays demonstrated that circ_0053943 exerts its biological function by stabilizing EGFR mRNA and regulating the downstream mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway. Collectively, circ_0053943 may promote UM progression by stabilizing EGFR mRNA and activating the MAPK/ERK signaling pathway through the formation of a circ_0053943/IGF2BP3/EGFR RNA-protein ternary complex, thus providing a potential biomarker and therapeutic target for UM.

CircRTTN upregulates EPHA2 to aggravate the malignant process of melanoma via sponging miR-890

BACKGROUND

Malignant melanoma is a kind of tumor derived from melanocytes, which has the characteristics of drug resistance and distant metastasis. Accumulating evidence has demonstrated that circular RNAs (circRNAs) are involved in the pathogenesis of melanoma. Our current study aimed to investigate the role and mechanism of circRTTN in melanoma progression.

METHODS

The levels of circRTTN, microRNA-890 (miR-890) and EPH receptor A2 (EPHA2) were examined via quantitative real-time PCR (qRT-PCR) and Western blot. Cell Counting Kit-8 (CCK-8), colony formation, 5-Ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry, transwell and tube formation assays were conducted to estimate the effects of circRTTN on growth, apoptosis, migration, invasion and angiogenesis of melanoma cells. Western blot was used to measure related marker protein levels. The interaction between miR-890 and circRTTN or EPHA2 was predicted by bioinformatics analysis and verified by dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. Xenograft assay was used to assess the effect of circRTTN in vivo.

RESULTS

CircRTTN and EPHA2 levels were up-regulated, while miR-890 was down-regulated in melanoma tissues and cells. CircRTTN knockdown restrained cell proliferation, migration, invasion and angiogenesis, but promoted cell apoptosis in vitro. CircRTTN was an effective molecular sponge for miR-890, and negatively regulated miR-890 expression. The suppressive role of circRTTN knockdown on cell growth, metastasis and angiogenesis in vitro was abated by blocking miR-890. MiR-890 directly targeted EPHA2. MiR-890 overexpression elicited a similar anti-tumor role in melanoma cells, which was abrogated by overexpression of EPHA2. In addition circRTTN knowdown markedly attenuated xenograft tumor growth in vivo.

CONCLUSION

Our findings demonstrated that circRTTN mediated melanoma progression via regulating the miR-890/ EPHA2 axis.

Role(s) of G3BPs in Human Pathogenesis

Ras-GTPase-activating protein (SH3 domain)-binding proteins (G3BP) are RNA binding proteins that play a critical role in stress granule (SG) formation. SGs protect critical mRNAs from various environmental stress conditions by regulating mRNA stability and translation to maintain regulated gene expression. Recent evidence suggests that G3BPs can also regulate mRNA expression through interactions with RNA outside of SGs. G3BPs have been associated with a number of disease states, including cancer progression, invasion, metastasis, and viral infections, and may be useful as a cancer therapeutic target. This review summarizes the biology of G3BP including their structure, function, localization, role in cancer progression, virus replication, mRNA stability, and SG formation. We will also discuss the potential of G3BPs as a therapeutic target. SIGNIFICANCE STATEMENT: This review will discuss the molecular mechanism(s) and functional role(s) of Ras-GTPase-activating protein (SH3 domain)-binding proteins in the context of stress granule formation, interaction with viruses, stability of RNA, and tumorigenesis.

Genetics and RNA Regulation of Uveal Melanoma

Uveal melanoma (UM) is the most common intraocular malignant tumor and the most frequent melanoma not affecting the skin. While the rate of UM occurrence is relatively low, about 50% of patients develop metastasis, primarily to the liver, with lethal outcome despite medical treatment. Notwithstanding that UM etiopathogenesis is still under investigation, a set of known mutations and chromosomal aberrations are associated with its pathogenesis and have a relevant prognostic value. The most frequently mutated genes are BAP1, EIF1AX, GNA11, GNAQ, and SF3B1, with mutually exclusive mutations occurring in GNAQ and GNA11, and almost mutually exclusive ones in BAP1 and SF3B1, and BAP1 and EIF1AX. Among chromosomal aberrations, monosomy of chromosome 3 is the most frequent, followed by gain of chromosome 8q, and full or partial loss of chromosomes 1 and 6. In addition, epigenetic mechanisms regulated by non-coding RNAs (ncRNA), namely microRNAs and long non-coding RNAs, have also been investigated. Several papers investigating the role of ncRNAs in UM have reported that their dysregulated expression affects cancer-related processes in both in vitro and in vivo models. This review will summarize current findings about genetic mutations, chromosomal aberrations, and ncRNA dysregulation establishing UM biology.

Regulation of mRNA stability contributes to the function of innate lymphoid cells in various diseases

Innate lymphoid cells (ILCs) are important subsets of innate immune cells that regulate mucosal immunity. ILCs include natural killer cells, innate lymphoid cells-1 (ILC1s), ILC2s, and ILC3s, which have extremely important roles in the immune system. In this review, we summarize the regulation of mRNA stability mediated through various factors in ILCs (e.g., cytokines, RNA-binding proteins, non-coding RNAs) and their roles in mediating functions in different ILC subsets. In addition, we discuss potential therapeutic targets for diseases such as chronic obstructive pulmonary disease, cancer, and pulmonary fibrosis by regulation of mRNA stability in ILCs, which may provide novel directions for future clinical research.

Circ_0004087 interaction with SND1 promotes docetaxel resistance in prostate cancer by boosting the mitosis error correction mechanism

Background

Acquisition of the chemoresistance to docetaxel (DTX), a microtubule-targeting agent, has been a huge obstacle in treatment for metastatic castration-resistant prostate cancer (mCRPC). Recently, strategies targeting the mitosis error correction mechanism including chromosomal passenger complex (CPC) were reported to reverse the resistance to microtubule-targeting anticancer agents. Meanwhile, accumulating evidence indicated the important roles of circRNAs in DTX resistance of prostate cancer (PCa). However, whether circRNAs could regulate DTX chemosensitivity by affecting the mitosis error correction mechanism remains unclear.

Methods

Expression patterns of circ_0004087 and BUB1 were determined through mining the public circRNA datasets and performing western blot and qRT-PCR assays. Agarose gel electrophoresis, Sanger sequencing, and RNase R treatment were conducted to examine the circular characteristics of circ_0004087. CircRNA pull-down, mass spectrometry analysis, Co-IP, and dual-luciferase reporter assays were performed to uncover the interaction among circ_0004087, SND1, and MYB. The effects of circ_0004087 and BUB1 on docetaxel-based chemotherapy were explored by flow cytometry and in vivo drug studies upon xenografted tumor model.

Results

In the present study, we revealed the profound interaction between a novel circRNA, circ_0004087, and the mitosis error correction mechanism. Mechanistically, circ_0004087 binding with transcriptional coactivator SND1 could stimulate the transactivation of MYB and enhance the expression of downstream target BUB1. In turn, elevated BUB1 expression further recruited CPC to centromeres and guaranteed the error-free mitosis of PCa cells. Biologically, the overexpression of circ_0004087 conferred while the knockdown impaired DTX resistance in PCa cells.

Conclusions

Our study uncovered the crucial role of circ_0004087/SND1/MYB/BUB1 axis in modulating the error mitosis correction mechanism and DTX chemoresistance, suggesting that circ_0004087 may serve as a valuable prognostic biomarker and a potential therapeutic target in DTX-resistant PCa patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02404-3.

N6-methyladenosine modification of circ_0003215 suppresses the pentose phosphate pathway and malignancy of colorectal cancer through the miR-663b/DLG4/G6PD axis

Circular RNAs (circRNAs) are a recently discovered kind of regulatory RNAs that have emerged as critical biomarkers of various types of cancers. Metabolic reprogramming has gradually been identified as a distinct hallmark of cancer cells. The pentose phosphate pathway (PPP) plays an indispensable role in satisfying the bioenergetic and biosynthetic demands of cancer cells. However, little is known about the role of circRNAs and PPP in colorectal cancer (CRC). The novel circ_0003215 was identified at low levels in CRC and was negatively correlated with larger tumor size, higher TNM stage, and lymph node metastasis. The decreased level of circ_0003215 was resulted from the RNA degradation by m6A writer protein YTHDF2. A series of functional assays demonstrated that circ_0003215 inhibited cell proliferation, migration, invasion, and CRC tumor metastasis in vivo and in vitro. Moreover, circ_0003215 regulated the expression of DLG4 via sponging miR-663b, thereby inducing the metabolic reprogramming in CRC. Mechanismly, DLG4 inhibited the PPP through the K48-linked ubiquitination of glucose-6-phosphate dehydrogenase (G6PD). Taken together, we have identified m6A-modified circ_0003215 as a novel regulator of metabolic glucose reprogramming that inhibited the PPP and the malignant phenotype of CRC via the miR-663b/DLG4/G6PD axis.

Construction of miRNA-lncRNA-mRNA co-expression network affecting EMT-mediated cisplatin resistance in ovarian cancer

Platinum resistance is one of the major concerns in ovarian cancer treatment. Recent evidence shows the critical role of epithelial-mesenchymal transition (EMT) in this resistance. Epithelial-like ovarian cancer cells show decreased sensitivity to cisplatin after cisplatin treatment. Our study prospected the association between epithelial phenotype and response to cisplatin in ovarian cancer. Microarray dataset GSE47856 was acquired from the GEO database. After identifying differentially expressed genes (DEGs) between epithelial-like and mesenchymal-like cells, the module identification analysis was performed using weighted gene co-expression network analysis (WGCNA). The gene ontology (GO) and pathway analyses of the most considerable modules were performed. The protein-protein interaction network was also constructed. The hub genes were specified using Cytoscape plugins MCODE and cytoHubba, followed by the survival analysis and data validation. Finally, the co-expression of miRNA-lncRNA-TF with the hub genes was reconstructed. The co-expression network analysis suggests 20 modules relating to the Epithelial phenotype. The antiquewhite4, brown and darkmagenta modules are the most significant non-preserved modules in the Epithelial phenotype and contain the most differentially expressed genes. GO, and KEGG pathway enrichment analyses on these modules divulge that these genes were primarily enriched in the focal adhesion, DNA replication pathways and stress response processes. ROC curve and overall survival rate analysis show that the co-expression pattern of the brown module's hub genes could be a potential prognostic biomarker for ovarian cancer cisplatin resistance.

Novel GSK-3 kinase inhibitor Pym-5 induces GSK-3β rather than GSK-3α-dependent melanogenesis in murine melanoma cells

BACKGROUND

Glycogen synthase kinase-3 (GSK-3) inhibitors are considered to activate Wnt/β-Catenin, which remains a controversial topic in melanoma treatment.

OBJECTIVE

Here, we have developed Pym-5, an attractive GSK-3 inhibitor. Using Pym-5 as a chemical tool to probe the GSK-3 biology, we aimed to investigate the potential of GSK-3 inhibition as a strategy of melanoma treatment and underlying mechanisms.

METHODS

Using pigment B16 and B16BL6 murine melanoma model in vitro and a zebrafish pigmentation model in vivo, we investigated Pym-5-meditaed activation of Wnt/β-Catenin, melanogenesis and antitumor response in melanoma treatment.

RESULTS

We found that Pym-5 delayed the growth and promoted melanogenesis of melanoma cells. Pym-5 activated the transcription of β-Catenin and responsive targets genes (AXIN2 and MITF), melanin biosynthesis genes (TYR, TYRP1 and TYRP2) and eventually elevated the production of melanin. Interestingly, genetic inactivation of GSK-3β, but not its paralogue GSK-3α, compromised Pym-5-mediated melanogenesis in B16 and B16BL6 cells.

CONCLUSION

These data provide insight into the potential therapeutic benefits obtained from activation of Wnt/β-Catenin signaling pathway and how Pym-5 can regulate melanin production and the rationale for future clinical application of GSK-3 inhibitor in melanoma patients.

Hsa_circ_0103232 promotes melanoma cells proliferation and invasion via targeting miR-661/RAB3D

Little is known about the role of hsa_circ_0103232 in melanoma. This study researched the role of hsa_circ_0103232 in melanoma progression. Hsa_circ_0103232 expression in clinical tissues of melanoma patients and melanoma cells was detected by qRT-PCR. Hsa_circ_0103232 localization in melanoma cells was visualized by fluorescence in situ hybridization. Hsa_circ_0103232 effect on melanoma cells viability, proliferation, migration, and invasion was explored by cell counting kit-8 (CCK-8) assay, Edu experiment, wound healing assay, and Transwell experiment. RNA pull-down assay and dual-luciferase reporter gene assay were performed to verify the binding of hsa_circ_0103232 with miR-661, and the binding of miR-661 and RAB3D. Xenograft tumor models were constructed. Western blot and immunohistochemistry were used for protein expression detection. Hsa_circ_0103232 expression was increased in melanoma patients, indicating lower overall survival. Hsa_circ_0103232 was mainly expressed in the cytoplasm of melanoma cells. Silencing hsa_circ_0103232 suppressed melanoma cell viability, proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) (P < 0.01). Hsa_circ_0103232 functioned as a sponge of miR-661 to increase RAB3D expression. miR-661 overexpression partially reversed hsa_circ_0103232 promoting effect on melanoma cells viability, proliferation, migration, invasion, and EMT (P < 0.01). In melanoma patients, hsa_circ_0103232 expression was negatively correlated with miR-661 and positively correlated with RAB3D. Silencing hsa_circ_0103232 suppressed melanoma cell growth in vivo and Ki67 and RAB3D expression in xenograft tumors (P < 0.01). Hsa_circ_0103232 is a tumor promoter in melanoma to enhance malignant phenotype and growth in vivo via sponging miR-661/RAB3D. Hsa_circ_0103232 may be a novel target for melanoma treatment.

The functional roles of the circRNA/Wnt axis in cancer

CircRNAs, covalently closed noncoding RNAs, are widely expressed in a wide range of species ranging from viruses to plants to mammals. CircRNAs were enriched in the Wnt pathway. Aberrant Wnt pathway activation is involved in the development of various types of cancers. Accumulating evidence indicates that the circRNA/Wnt axis modulates the expression of cancer-associated genes and then regulates cancer progression. Wnt pathway-related circRNA expression is obviously associated with many clinical characteristics. CircRNAs could regulate cell biological functions by interacting with the Wnt pathway. Moreover, Wnt pathway-related circRNAs are promising potential biomarkers for cancer diagnosis, prognosis evaluation, and treatment. In our review, we summarized the recent research progress on the role and clinical application of Wnt pathway-related circRNAs in tumorigenesis and progression.

The roles of G3BP1 in human diseases (review)

Ras-GTPase-activating protein binding protein 1 (G3BP1) is a multifunctional binding protein involved in a variety of biological functions, including cell proliferation, metastasis, apoptosis, differentiation and RNA metabolism. It has been revealed that G3BP1, as an antiviral factor, can interact with viral proteins and regulate the assembly of stress granules (SGs), which can inhibit viral replication. Furthermore, several viruses have the ability to hijack G3BP1 as a cofactor, recruiting translation initiation factors to promote viral proliferation. However, many functions of G3BP1 are associated with other diseases. In various cancers, G3BP1 is a cancer-promoting factor, which can promote the proliferation, invasion and metastasis of cancer cells. Moreover, compared with normal tissues, G3BP1 expression is higher in tumor tissues, indicating that it can be used as an indicator for cancer diagnosis. In this review, the structure of G3BP1 and the regulation of G3BP1 in multiple dimensions are described. In addition, the effects and potential mechanisms of G3BP1 on various carcinomas, viral infections, nervous system diseases and cardiovascular diseases are elucidated, which may provide a direction for clinical applications of G3BP1 in the future.

Analyses of circRNA and mRNA Profiles in Vogt-Koyanagi-Harada Disease

Recent studies revealed that circular RNAs (circRNAs) are important in numerous biological process and involved in autoimmune diseases. However, their role in Vogt-Koyanagi-Harada (VKH) disease, a classical autoimmune disease, is not yet known. This research aimed to study the expression profile of mRNAs, microRNAs (miRNAs) and circRNAs and investigate the influence of circRNAs on the pathogenesis of VKH disease. We identified circRNAs, miRNAs, and mRNAs expression profiles in CD4⁺ T cells between 4 VKH patients and 3 healthy controls using the whole-transcriptome sequencing (RNA-seq) technique. We discovered that a total of 5088 mRNAs, 451 circRNAs and 433 miRNAs were differently expressed. The GO and KEGG pathway enrichment analyses were performed for significantly differentially expressed circRNAs and mRNAs. GSEA was conducted for all mRNAs. The functional enrichment suggested that the inflammatory response, the adaptive immune response, NF-kappa B signaling pathway, Th17 cell differentiation, Th1 and Th2 cell differentiation and T cell receptor signaling pathway were associated with VKH disease. In addition, based on the immune-related genes we screened, the circRNA-miRNA-mRNA ceRNA network was analyzed and constructed. Ten differently expressed mRNAs (LAT, ZAP70, ITK, ICOS, RASGRP1, PAG1, PLCG1, PRKCQ, LCK, CARD11) and 5 differently expressed circRNAs (hsa_circ_0033144, hsa_circ_0000233, hsa_circ_0000396, hsa_circ_0001924, hsa_circ_0001320) were selected to be validated by Real-time qPCR (RT-qPCR). The results of RT-qPCR turned out to be consistent with RNA-seq data. Further analysis showed that hsa_circ_0001320 and hsa_circ_0001924 may serve as crucial candidate marker genes of VKH disease. These results reveal that circRNAs may have a crucial immunomodulatory function in the pathophysiological process of VKH disease.

Tumor-promoting properties of karyopherin β1 in melanoma by stabilizing Ras-GTPase-activating protein SH3 domain-binding protein 1

The nuclear import receptor karyopherin β1 (KPNB1), a member of the Karyopherin protein family, is reported to be overexpressed in various cancers and promote carcinogenesis. By analyzing the correlation between the expression of KPNB1 and the overall survival rate of melanoma patients, we found that melanoma patients with higher expression of KPNB1 had worse survival. Furthermore, the database analyzed that the KPNB1 mRNA level was higher in melanoma samples than that in skin nevus tissues. We thus proposed that KPNB1 played a role in promoting melanoma development, and conducted gain-of- and loss-of-function experiments to test our hypothesis. We found that KPNB1 knockdown significantly retarded the growth and metastasis of melanoma cells in vitro and in vivo, and increased their sensitivity towards the anti-tumor drug cisplatin. KPNB1 overexpression had opposite effects. Notably, in melanoma cells, KPNB1 overexpression significantly decreased Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) protein level, which was also overexpressed in melanoma samples and enhanced malignant behaviors of melanoma cells. We further demonstrated that KPNB1 overexpression induced deubiquitination of G3BP1, and prevented its degradation. However, KPNB1 overexpression hardly affected the nuclear translocation of G3BP1. Additionally, alterations induced by KPNB1 overexpression were partly reversed by G3BP1 inhibition. Therefore, the results suggest that KPNB1 may promote melanoma progression by stabilizing the G3BP1 protein. KPNB1-G3BP1 axis represents a potential therapeutic targetable node for melanoma.

The expression and function of miR-622 in a variety of tumors

Cancer is a heavy burden worldwide, with high morbidity and mortality rates. Cancer treatments currently involve surgical and nonsurgical approaches. Molecular targeted therapy is the latest breakthrough. miRNAs are small noncoding RNAs found in plants and animals that play a role in cancer and various diseases through influencing numerous biological processes, such as cell proliferation, apoptosis, the immune response, and drug resistance. One miRNA, miR-622, has been shown to regulate various pathways to influence disease processes. Abnormal miR-622 expression can promote or inhibit liver, colorectal, and breast cancers and other tumors, such as glioma. Herein, we reviewed the expression levels and clinical effects of miR-622 in various tumors and summarized its mechanisms and related molecules.

Regulation of epigenetic homeostasis in uveal melanoma and retinoblastoma

Uveal melanoma (UM) and retinoblastoma (RB), which cause blindness and even death, are the most frequently observed primary intraocular malignancies in adults and children, respectively. Epigenetic studies have shown that changes in the epigenome contribute to the rapid progression of both UM and RB following classic genetic changes. The loss of epigenetic homeostasis plays an important role in oncogenesis by disrupting the normal patterns of gene expression. The targetable nature of epigenetic modifications provides a unique opportunity to optimize treatment paradigms and establish new therapeutic options for both UM and RB with these aberrant epigenetic modifications. We aimed to review the research findings regarding relevant epigenetic changes in UM and RB. Herein, we 1) summarize the literature, with an emphasis on epigenetic alterations, including DNA methylation, histone modifications, RNA modifications, noncoding RNAs and an abnormal chromosomal architecture; 2) elaborate on the regulatory role of epigenetic modifications in biological processes during tumorigenesis; and 3) propose promising therapeutic candidates for epigenetic targets and update the list of epigenetic drugs for the treatment of UM and RB. In summary, we endeavour to depict the epigenetic landscape of primary intraocular malignancy tumorigenesis and provide potential epigenetic targets in the treatment of these tumours.

Circular RNA circCRKL inhibits the proliferation of acute myeloid leukemia cells via the miR-196a-5p/miR-196b-5p/p27 axis

As a new type of non-coding RNA, the role of circular RNA (circRNA) in various diseases and tumors has received considerable attention. Studies have shown that circRNAs play an important role in the progression of acute myeloid leukemia (AML) via different mechanisms. However, the specific underlying molecular mechanism of circRNAs in the proliferation of AML cells remians unclear. This study aimed to clarify the biological role and mechanism of circCRKL in AML. The results indicated low circCRKL expression in AML cell lines and samples. Moreover, the overexpression of circCRKL inhibited the proliferation and colony-forming ability of AML cells, while its silencing promoted them. In addition, bioinformatics tools and luciferase assays revealed that circCRKL could sponge miR-196a-5p and miR-196b-5p to promote the expression of p27. Furthermore, circCRKL inhibited AML cell proliferation via the miR-196a-5p/miR-196b-5p/p27 axis, suggesting a potential new target for AML therapy.

circUSP34 accelerates osteosarcoma malignant progression by sponging miR-16-5p

Osteosarcoma (OS) is a primary and highly malignant mesenchymal tissue tumor. The specific pathological mechanism underlying disease initiation or progression remains unclear. Circular RNAs (circRNAs) are a type of covalently circular RNA with a head-to-tail junction site. In this study, we aimed to investigate the sponging mechanism between circRNAs and microRNAs (miRNAs) in OS. Based on the inhibited effect of miR-16-5p reported on OS, circUSP34 was analyzed as a sponge of miR-16-5p via Starbase. We found that circUSP34 promoted the proliferation, migration, and invasion of OS in vitro and in vivo. circUSP34 increased but miR-16-5p decreased in OS by qRT-PCR. Function assays showed that the malignancy of OS cells, including proliferation, migration, and invasion, was inhibited after knocking out circUSP34. Western blotting results showed that the expression level of vimentin and Ki-67 decreased. Similarly, miR-16-5p mimic compromised the proliferation, migration, and invasion of OS cells. FISH assay results indicated that circUSP34 and miR-16-5p were colocalized in the cytoplasm. The sponging mechanism of circUSP34 and miR-16-5p was verified by dual-luciferase reporter assay, RNA immunoprecipitation (RIP), and RNA pull down assays. Interestingly, the miR-16-5p inhibitor partly reversed the inhibitory effect of sh-circUSP34 on the malignancy of OS cells. Further, mice tumors for IHC indicated that vimentin, N-cadherin, and Ki-67 protein expression decreased, but E-cadherin protein expression increased. Collectively, circUSP34 promoted OS malignancy, including proliferation, migration, and invasion, by sponging miR-16-5p. It can serve as a potential therapeutic target and biomarker.

Circular RNA as a Potential Biomarker for Melanoma: A Systematic Review

Circular RNAs (circRNAs) are newly discovered RNAs with covalently looped structures. Due to their resistance to RNAase degradation and tissue-specific expression, circRNAs are expected to be potential biomarkers in early diagnosis and target treatment of many diseases. However, the role of circRNAs in melanoma still needs to be systematically reviewed for better understanding and further research. Based on published articles in PubMed, Embase, Cochrane Library, and Web of Science database, we systematically reviewed the implications and recent advances of circRNAs in melanoma, focusing on function, mechanism, and correlation with melanoma progression. According to inclusion and exclusion criteria, a total of 19 articles were finally included in this systematic review. Of the 19 studies, 17 used human samples, including melanoma tissues (n = 16) and blood serum of patients with melanoma (n = 1). The sample size of the study group ranged from 20 to 105 based on the reported data. Several studies explored the association between circRNAs and clinicopathological characteristics. circRNA dysregulation was commonly observed in melanoma patients. circRNAs function in melanoma by miRNA sponging and interaction with RNA binding proteins (RBP), ultimately controlling several important signaling pathways and cancer-related cellular processes, including proliferation, migration, invasion, metastasis, apoptosis, and glucose metabolism. circRNA expression could be associated with prognostic factors and drug responses, consolidating the potential clinical value in melanoma. Herein, we clarified the functional, prognostic, and predictive roles of circRNAs in melanoma in this systematic review, providing future directions for studies on melanoma-associated circRNAs.

CircularRNA_0119872 regulates the microRNA-582-3p/E2F transcription factor 3 pathway to promote the progression of malignant melanoma

OBJECTIVES

Malignant melanoma (MM) is an invasive tumor that poses a threat to patient health. Circular RNAs (circRNAs) are important regulators of MM carcinogenesis. In this study, we investigated the expression characteristics and biological functions of, and mechanism underlying, circ_0119872 expression in MM.

METHODS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was employed to examine the circ_0119872, microRNA (miR)-582-3p, and E2F transcription factor 3 (E2F3) mRNA expression levels in MM tissues and cell lines. Western blotting was performed to quantify E2F3 protein expression. MM cells with circ_0119872 knockdown were established, and cell counting kit 8 (CCK-8) and transwell assays were utilized to examine the function of circ_0119872 and its effects on the malignant characteristics of MM cells. The MiRDB and TargetScan databases were used to predict the target genes of miR-582-3p. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to explore the biological functions of the target genes of miR-582-3p. Additionally, a dual-luciferase reporter gene experiment was performed to verify the targeting relationship between circ_0119872 and miR-582-3p as well as that between miR-582-3p and E2F3.

RESULTS

Circ_0119872 was remarkably upregulated in MM tissues and cell lines. Circ_0119872 knockdown suppressed the cell proliferation and metastasis In addition, miR-582-3p was identified as a downstream target of circ_0119872. The target genes of miR-193a-3p are involved in melanogenesis and cancer-related signaling pathways. Mechanistically, circ_0119872 facilitated MM progression by adsorbing miR-582-3p and upregulating E2F3 expression.

CONCLUSION

Circ_0119872 is an oncogenic circRNA that participates in the promotion of MM progression by regulating the miR-582-3p/E2F3 axis.