CircHIPK3 promotes proliferation and metastasis and inhibits apoptosis of renal cancer cells by inhibiting MiR-485-3p

The prognosis of ciRS-7 and circHIPK3 in pan-cancer: a mini-review and meta-analysis

BACKGROUND

Circular RNAs (circRNAs) are increasingly recognized for their potential as cancer biomarkers. Although various studies have investigated the biological function of ciRS-7 and circHIPK3 in malignant tumors, their prognostic value in pan-cancer has not been systematically analyzed.

METHODS

We systematically searched the PubMed, Web of Science, and Cochrane Library databases from January 1, 1990, to October 14, 2024. The impact of ciRS-7 or circHIPK3 on prognostic outcomes, including overall survival (OS) and disease-free survival (DFS), was assessed by pooled hazard ratios (HR). The association between CiRS-7 or circHIPK3 and clinical features was evaluated using odds ratios (OR). The Data analysis was conducted using Review Manager 5.4.

RESULTS

For most cancers, our meta-analysis of 14 studies (N = 2140) and 15 studies (N = 1045) showed that high ciRS-7 and circHIPK3 were associated with worse OS. Pooled analysis of 5 studies (N = 421) and 2 studies (N = 248) indicated that high ciRS-7 and circHIPK3 were also associated with shorter DFS. Additionally, high ciRS-7 and circHIPK3 expression were associated with worse histological grade, higher TNM stage, larger tumor size, more lymph node and distant metastasis.

CONCLUSION

High ciRS-7 and circHIPK3 were significantly associated with poor prognosis and advanced clinical features in most cancers, suggesting their potential as prognostic biomarkers.

Exosomal non-coding RNAs (ncRNAs) as potential biomarkers in tumor early diagnosis

Exosomes, extracellular vesicles carrying a cargo rich in various non-coding RNAs (ncRNAs), have emerged as crucial mediators of intercellular communication. Their stability, abundance, and specificity make exosomal ncRNAs promising candidates for biomarker discovery. The discovery of exosomal ncRNAs has unveiled a novel avenue for the exploration of biomarkers in tumor early diagnosis. This review consolidates current knowledge on the role of exosomal ncRNAs as potential biomarkers in the early detection of various tumors. We provide an overview of recent studies demonstrating the diagnostic potential of exosomal ncRNAs across multiple cancer types, highlighting their sensitivity, specificity, and feasibility for early detection. This review underscores the potential of exosomal ncRNAs as non-invasive biomarkers for early tumor diagnosis, paving the way for improved clinical outcomes through timely intervention and personalized management strategies.

[Research Progress of Circular RNA CircHIPK3 in Non-small Cell Lung Cancer]

Lung cancer ranks among the most prevalent and deadliest malignancies worldwide. Despite significant strides in targeted therapies and immunotherapy for lung cancer, curing the disease remains a highly prioritized issue. Circular RNAs (circRNAs), recently discovered RNA molecules characterized by covalently closed loop structures, possess features such as structural stability, sequence conservation, and disease-specific expression. Cutting-edge medical research has linked circRNA dysregulation to the progression of various cancers. Among these, circular RNA HIPK3 (circHIPK3), an oncogenic gene primarily derived from the second exon of the HIPK3 gene, has emerged as a focal point of investigation. Increasing evidences suggest that circHIPK3 is involved in the development of non-small cell lung cancer (NSCLC) and other malignancies. Aberrant expression of circHIPK3 is closely associated with the disease mechanisms, diagnosis, treatment, and prognosis of NSCLC. This review discusses the latest research advancements on circHIPK3 in NSCLC, aiming to promote precise diagnosis and treatment of lung cancer.
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Hsa_circ_0000129 knockdown attenuates proliferation and migration in keloid fibroblasts by targeting miR-485-3p/SGMS2 pathway

BACKGROUND

Aberrant biofunction of circular RNAs (circRNAs) is potently implicated in keloid formation. However, their roles have been underinvestigated. Recent evidence has demonstrated the pro-tumor role of circ_0000129 in cancers, and yet its role in keloid remains elusive.

METHODS

RT-qPCR analysis and or western blotting of miR-485-3p, circ_0000129, and SGMS2 in keloid tissues and keloid fibroblasts was implemented. CCK8, EdU, scratch wound healing, and Transwell migration assays were perfomed to determine the keloid fibroblast proliferation and migration. Luciferase reporter and RIP assays were adopted to analyze the interaction among circ_0000129, miR-485-3p and SGMS2.

RESULTS

In keloid tissues and keloid fibroblasts, circ_0000129 and SGMS2 were amplified, although miR-485-3p expression was downregulated. Furthermore, siRNAs-targeting endogenous circ_0000129 resulted in proliferation and migration defect of keloid fibroblasts. MiR-485-3p was simultaneously recognized by circ_0000129 and SGMS2 3'UTR. Rescued functional assays also illustrated that miR-485-3p loss was beneficial to the proliferation and migration of keloid fibroblasts, and these promoting changes were nullified by accompanied silence circ_0000129 or SGMS2.

CONCLUSION

Circ_0000129 sponges miR-485-3p and releases expression of SGMS2 from the miR-485-3p suppression, promoting migration and proliferation of keloid fibroblasts, suggesting targeting circ_0000129/miR-485-3p/SGMS2 might be a promising strategy against keloid fibroblasts.

AVAILABILITY OF DATA AND MATERIAL

All data generated or analyzed during this study are included in this article.

SPI1 Mediates N-Myristoyltransferase 1 to Advance Gastric Cancer Progression via PI3K/AKT/mTOR Pathway

Gastric cancer (GC) is a common digestive tract malignancy worldwide. N-myristoyltransferase 1 (NMT1) has been implicated in many cancers, but its association with gastric cancer remains to be clarified. Thus, this paper elucidated the role of NMT1 in GC. The NMT1 expression level in GC and normal tissue samples as well as the relationship between NMT1 high or low expression and overall survival in GC was analyzed via GEPIA. GC cells were transfected with NMT1 or SPI1 overexpression plasmid and short hairpin RNA against NMT1 (shNMT1) or shSPI1. NMT1, SPI1, p-PI3K, PI3K, p-AKT, AKT, p-mTOR, and mTOR levels were detected through qRT-PCR and western blot. MTT, wound healing, and transwell assays were applied to test cell viability, migration, and invasion. The binding relationship of SPI1 and NMT1 was determined through a dual-luciferase reporter assay and chromatin immunoprecipitation. NMT1 was upregulated in GC, the high level of which connected with a poor prognosis. Overexpressed NMT1 elevated viability, migration rate, and invasion rate of GC cells, whereas NMT1 knockdown leads to the opposite results. Besides, SPI1 could bind to NMT1. Overexpressed NMT1 reversed the effects of shSPI1 on decreasing viability, migration, invasion, p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR in GC cells, and NMT1 knockdown reversed the effects of SPI1 overexpression on increasing viability, migration, invasion, p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR. SPI1 upregulated NMT1 to facilitate the malignant behaviors of GC cells through the PI3K/AKT/mTOR pathway.

Hsa_circ_0000129 drives tumor growth via sequestering miR-485-3p and upregulating SPIN1 in breast cancer

BACKGROUND

Breast cancer (BC) is second cancer frequently occurring worldwide. Circular RNA hsa_circ_0000129 (circ_0000129) exerts a tumor-promoting effect in BC. Nevertheless, the molecular mechanisms mediated by the upregulation of circ_0000129 during BC progression are not well understood.

METHODS

Forty-five BC patients were recruited for the research. Changes in circ_0000129 levels were detected with quantitative reverse transcription-polymerase chain reaction. Cell proliferation, apoptosis, migration, invasion, and angiopoiesis were determined by cell counting, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays. Protein levels were detected by western blot analysis. The regulatory mechanism of circ_0000129 was predicted by bioinformatics analysis and validated by dual-luciferase reporter and RNA immunoprecipitation assays. In vivo experiments were carried out to verify the function of circ_0000129.

RESULTS

Circ_0000129 was overexpressed in BC samples and cell lines. Functionally, circ_0000129 silencing reduced cell proliferation, migration, invasion, and promoted cell apoptosis, as well as induced HUVEC angiopoiesis in vitro. Furthermore, circ_0000129 knockdown decreased BC cell growth in mouse xenograft models. Mechanically, circ_0000129 interacted with miR-485-3p to mediate the inhibiting effect of miR-485-3p on SPIN1. Silenced miR-485-3p expression weakened the inhibiting effect of circ_0000129 knockdown on BC cell malignant behaviors. Also, forced SPIN1 expression weakened miR-485-3p upregulation mediated effects on BC cell malignant behaviors.

CONCLUSION

Circ_0000129 acted as a miR-485-3p sponge molecular to mediate expression, thus promoting BC progression.

CircRNA High Mobility Group At-hook 2 regulates cell proliferation, metastasis and glycolytic metabolism of nonsmall cell lung cancer by targeting miR-331-3p to upregulate High Mobility Group At-hook 2

Increasing circular RNAs (circRNAs) have been identified as pivotal players in nonsmall cell lung cancer (NSCLC). The study will explore the function and mechanism of circRNA High Mobility Group AT-hook 2 (circHMGA2) in NSCLC. The circHMGA2, microRNA-331-3p (miR-331-3p) and HMGA2 expression analyses were performed via quantitative real-time PCR. Cell proliferation was assessed via Cell Counting Kit-8 and colony formation assays. Transwell migration/invasion assays were used for measuring cell metastasis. Glucose consumption and lactate production were determined for glycolytic evaluation. Western blot was used to detect the protein expression of HMGA2 and glycolytic markers. Target analysis was performed by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Xenograft tumor assay in mice was conducted for the investigation of circHMGA2 in vivo . CircHMGA2 was overexpressed in NSCLC, and high circHMGA2 level might be related to NSCLC metastasis and poor prognosis. In-vitro assays suggested that NSCLC cell growth, metastasis and glycolysis were retarded by downregulation of circHMGA2. Upregulation of HMGA2 was shown to return the anticancer response of circHMGA2 knockdown in NSCLC cells. Through interacting with miR-331-3p, circHMGA2 could regulate the expression of HMGA2. In addition, circHMGA2/miR-331-3p and miR-331-3p/HMGA2 axes were affirmed in NSCLC regulation. In-vivo analysis indicated that circHMGA2 inhibition also reduced tumorigenesis and glycolysis of NSCLC via the miR-331-3p/HMGA2 axis. This study disclosed the oncogenic role of circHMGA2 and the regulatory circHMGA2/miR-331-3p/HMGA2 axis in NSCLC.

Understanding the Dual Roles of CircHIPK3 in Tumorigenesis and Tumor Progression

CircHIPK3 is a type of endogenous circular RNA, which contains a covalently closed circular structure and cannot encode protein or polypeptide. CircHIPK3 is unusually expressed in varieties of tumors and plays dual roles of tumor promotion or tumor inhibition in tumorigenesis and development of tumors by serving as the sponge for miRNA in multiple tumors. Here, we reviewed the differential expression, the dual functions, the regulation mechanism, and the network in a variety of tumors as well as the potential value for the diagnosis and treatment of tumors, which are of great significance for our comprehensive understanding of the roles and mechanisms of circHIPK3 in tumors.

Propofol inhibits cell apoptosis and inflammatory response in ox-LDL-induced human umbilical vein endothelial cells through the modulation of the circ_0003645/miR-149-3p/TRAF7 axis

BACKGROUND: Propofol is an anesthetic agent and can impede the progression of human diseases. Circular RNA (circRNA) circ_0003645 has been identified to promote the development of atherosclerosis (AS). This study aimed at the functional mechanism of propofol and circ_0003645 in AS. METHODS: AS cell model was established by treatment of oxidized low-density lipoprotein (ox-LDL) in human umbilical vein endothelial cells (HUVECs). Cell viability or apoptosis detection was performed by Cell Counting Kit-8 (CCK-8) assay and flow cytometry. Circ_0003645, microRNA-149-3p (miR-149-3p) and tumor necrosis factor receptor-associated factor 7 (TRAF7) levels were determined by the quantitative real-time polymerase chain reaction (qRT-PCR). Inflammatory cytokines were examined using enzyme-linked immunosorbent assay (ELISA). Protein analysis was conducted by western blot. The interaction of miR-149-3p and circ_0003645 or TRAF7 was analyzed using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. RESULTS: Treatment of ox-LDL inhibited cell viability and enhanced apoptosis in HUVECs to establish the AS cell model. Propofol protected against cell viability inhibition and apoptosis promotion in AS cell model. Circ_0003645 expression was downregulated by propofol in AS cell model. Propofol alleviated cell apoptosis and inflammation by decreasing the circ_0003645 level. Circ_0003645 targeted miR-149-3p, and circ_0003645/miR-149-3p axis was involved in the functional regulation of propofol. TRAF7 was the target of miR-149-3p. Inhibition of miR-149-3p affected the function of propofol by upregulating the TRAF7 expression. Circ_0003645 sponged miR-149-3p to induce the upregulation of TRAF7 following propofol treatment. CONCLUSION: It has been suggested that propofol acted as an inhibitor against the ox-LDL-induced cell injury by the circ_0003645/miR-149-3p/TRAF7 axis.

The Diagnostic and Therapeutic Role of Circular RNA HIPK3 in Human Diseases

Circular RNAs (circRNAs) are a class of noncoding RNAs with closed-loop of single-stranded RNA structure. Although most of the circRNAs do not directly encode proteins, emerging evidence suggests that circRNAs play a pivotal and complex role in multiple biological processes by regulating gene expression. As one of the most popular circRNAs, circular homeodomain-interacting protein kinase 3 (circHIPK3) has frequently gained the interest of researchers in recent years. Accumulating studies have demonstrated the significant impacts on the occurrence and development of multiple human diseases including cancers, cardiovascular diseases, diabetes mellitus, inflammatory diseases, and others. The present review aims to provide a detailed description of the functions of circHIPK3 and comprehensively overview the diagnostic and therapeutic value of circHIPK3 in these certain diseases.

Exosomal miR-485-3p derived from pancreatic ductal epithelial cells inhibits pancreatic cancer metastasis through targeting PAK1

BACKGROUND

Cell competition is an important feature in pancreatic cancer (PC) progression, but the underlying mechanism remains elusive. This study aims to explore the role of exosomes derived from normal pancreatic ductal epithelial cells involved in PC progression.

METHODS

PC cells and pancreatic stellate cells (PSCs) were treated with exosomes isolated from pancreatic ductal epithelial cells. Cell proliferation was assessed by CCK8 assays. Cell migration and invasion were assessed by Transwell assays. PC and matched adjacent non-tumor tissue specimens were obtained from 46 patients pathologically diagnosed with PC at Peking University First Hospital from 2013 to 2017. Tissue miR-485-3p and p21-activated kinase-1 (PAK1) expression was examined by real-time polymerase chain reaction (RT-PCR), and the relationship of the two was analyzed using Pearman's product-moment correlation. The clinical significance of miR-485-3p was analyzed using the Chi-square test, Wilcoxon rank-sum test, and Fisher exact probability, respectively. The binding of miR-485-3p to PAK1 5'-untranslated region (5'-UTR) was examined by luciferase assay. PC cells were xenografted into nude mice as a PC metastasis model.

RESULTS

Exosomes from pancreatic ductal epithelial cells suppressed PC cell migration and invasion as well as the secretion and migration of PSCs. MiR-485-3p was enriched in the exosomes of pancreatic ductal epithelial cells but deficient in those of PC cells and PSCs, in accordance with the lower level in PSCs and PC cells than that in pancreatic ductal cells. And the mature miR-485-3p could be delivered into these cells by the exosomes secreted by normal pancreatic duct cells, to inhibit PC cell migration and invasion. Clinical data analysis showed that miR-485-3p was significantly decreased in PC tissues (P < 0.05) and was negatively associated with lymphovascular invasion (P = 0.044). As a direct target of miR-485-3p, PAK1 was found to exert an inhibitory effect on PC cells, and there was a significantly negative correlation between the expression levels of miR-485-3p and PAK1 (r = -0.6525, P < 0.0001) in PC tissues. Moreover, miR-485-3p could suppress PC metastasis in vivo by targeting p21-activated kinase-1.

CONCLUSIONS

Exosomal miR-485-3p delivered by normal pancreatic ductal epithelial cells into PC cells inhibits PC metastasis by directly targeting PAK1. The restoration of miR-485-3p by exosomes or some other vehicle might be a novel approach for PC treatment.

Circular RNAs as prognostic and diagnostic biomarkers in renal cell carcinoma

BACKGROUND

Circular RNAs (circRNAs) play pivotal roles in proliferation, apoptosis, migration, and invasion of renal cell carcinoma (RCC) cells. This study is aimed to systematically summarize the current evidence regarding the clinical implications of circRNAs in RCC patients.

METHODS

A systematic search in PubMed, Embase, and Web of Science was performed until January 1, 2022. The correlation between the expression of circRNAs and clinicopathological, prognostic, and diagnostic features of RCC was evaluated using the meta-analysis.

RESULTS

Ultimately, 41 studies with 3485 RCC patients were included in this study: 26 studies for clinicopathological features, 31 studies for prognosis, and eight studies for diagnosis. Altered expression of circRNAs was significantly associated with clinicopathological characteristics of RCC, including tumor size, tumor stage, lymph node metastasis, distant metastasis, and TNM stage. The tumor promoter circRNAs were associated with reduced overall survival (OS) (Hazard Ratio (HR) = 1.98, 95% confidence interval [CI] 1.68-2.34) and disease/progression/recurrence-free survival (DFS/PFS/RFS) (HR = 2.34, 95% CI 1.85-2.97). Contrarily, the tumor suppressor circRNAs were linked with better OS (HR = 0.49, 95% CI 0.40-0.60) and DFS/PFS/RFS (HR = 0.40, 95% CI 0.28-0.59). The pooled sensitivity and specificity of circRNAs for RCC diagnosis in tissue samples were both 0.84. These results in fluid samples (serum and urine) were 0.78 and 0.69, respectively.

CONCLUSION

CircRNAs can serve as promising diagnostic and prognostic biomarkers for RCC.

DNA methylation influences the CTCF-modulated transcription of RASSF1A in lung cancer cells

Ras-association domain family 1A (RASSF1A) is one of the most methylated genes in lung cancer (LC). We investigate whether the high DNA methylation level of RASSF1A can relieve the resistance of RASSF1A to LC by inhibiting RASSF1A's transcription factor binding to RASSF1A. RASSF1A expression in tissues and cells was tested utilizing quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot. RASSF1A expression and RASSF1A methylation level in LC cells exposed to 5-Aza-dc were assessed by qRT-PCR and quantitative methylation-specific PCR. The association between CTCF and RASSF1A was assessed using hTFtarget, ChIP, and luciferase reporter gene analysis. The effects of 5-Aza-dc, CTCF, and RASSF1A on cell biological behaviors and epithelial-mesenchymal transition (EMT)-related markers were assessed by cell function experiments and Western blot. Moreover, we constructed the xenograft tumor and pulmonary nodule metastasis models, and assessed tumor volume and weight. RASSF1A expression and pulmonary nodule metastasis were tested utilizing qRT-PCR, Western blot, and H&E staining. RASSF1A was under-expressed in LC tissues and cells. 5-Aza-dc enhanced RASSF1A level and weakened RASSF1A methylation level in LC cells. RASSF1A silencing neutralized 5-Aza-dc-mediated repressing effects on LC cell biological function and EMT. The loss of CTCF binding to RASSF1A in LC cells was associated with DNA methylation. The effect of 5-Aza-dc on RASSF1A level, LC cell malignant behaviors, and EMT-related factors were strengthened by CTCF upregulation. RASSF1A overexpression suppressed LC tumor growth and pulmonary nodule metastasis in vivo. DNA methylation blocked the modulation of RASSF1A expression by CTCF and relieved the resistance of RASSF1A to LC.

Circulating miR-1246 and miR-485-3p as Promising Biomarkers of Clinical Response and Outcome in Melanoma Patients Treated with Targeted Therapy

Despite the significant improvements in advanced melanoma therapy, there is still a pressing need for biomarkers that can predict patient response and prognosis, and therefore support rational treatment decisions. Here, we investigated whether circulating miRNAs could be biomarkers of clinical outcomes in patients treated with targeted therapy. Using next-generation sequencing, we profiled plasma miRNAs at baseline and at progression in patients treated with BRAF inhibitors (BRAFi) or BRAFi + MEKi. Selected miRNAs associated with response to therapy were subjected to validation by real-time quantitative RT-PCR . Receiver Operating Characteristics (ROC), Kaplan–Meier and univariate and multivariate Cox regression analyses were performed on the validated miR-1246 and miR-485-3p baseline levels. The median baseline levels of miR-1246 and miR-485-3p were significantly higher and lower, respectively, in the group of patients not responding to therapy (NRs) as compared with the group of responding patients (Rs). In Rs, a trend toward an increase in miR-1246 and a decrease in miR-485-3p was observed at progression. Baseline miR-1246 level and the miR-1246/miR-485-3p ratio showed a good ability to discriminate between Rs and NRs. Poorer PFS and OS were observed in patients with unfavorable levels of at least one miRNA. In multivariate analysis, a low level of miR-485-3p and a high miR-1246/miR-485-3p ratio remained independent negative prognostic factors for PFS, while a high miR-1246/miR-485-3p ratio was associated with an increased risk of mortality, although statistical significance was not reached. Evaluation of miR-1246 and miR-485-3p baseline plasma levels might help clinicians to identify melanoma patients most likely to be unresponsive to targeted therapy or at higher risk for short-term PFS and mortality, thus improving their management.

CircHIPK3 prevents chondrocyte apoptosis and cartilage degradation by sponging miR-30a-3p and promoting PON2

Osteoarthritis (OA) is a common joint disease featured by the deterioration of articular cartilage and chondrocyte death. Emerging evidence has indicated that circular RNAs (circRNAs) play an essential role in OA progress. Here, we found that the expression of circHIPK3 was significantly decreased in human and mouse OA cartilage. Knocking down circHIPK3 increased apoptosis and intracellular ROS level in HC‐a chondrocytes. We performed proteomic studies and identified that circHIPK3 regulated chondrocyte apoptosis through the mitochondrial pathway. Results of JC‐1 staining and western blot further confirmed that mitochondrial outer membrane permeabilization was promoted in HC‐a chondrocytes transfected by circHIPK3 siRNA. In terms of mechanism, we showed that PON2 functioned as a potential target of circHIPK3 to regulate chondrocyte apoptosis. Moreover, we revealed that circHIPK3 interacted with miR‐30a‐3p to regulate PON2 expression in chondrocytes. Taken together, our findings suggested that circHIPK3 regulated chondrocyte apoptosis by mitochondrial pathway, and targeting the circHIPK3/miR‐30a‐3p/PON2 axis might be a potential strategy for OA treatment.

The functions, oncogenic roles, and clinical significance of circular RNAs in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common form of malignancy affecting the kidneys. Circular RNAs (circRNAs) are non-coding RNAs that are derived from exonic or intronic sequences through a selective shearing process. There is growing evidence that these circRNAs can influence a range of biological pathways by serving as protein decoys, microRNA sponges, regulators of transcriptional activity, or templates for protein translation. The dysregulation of circRNA expression patterns is a hallmark of RCC and other cancer types, and there is strong evidence that these RNA species can play central roles in the onset and progression of RCC tumors. In the present review, we summarized recent findings on the functional roles and clinical impacts of circRNAs in RCC. Further, we discussed their potential utility as diagnostic biomarkers or targets for therapeutic intervention.

The novel circular RNA HIPK3 accelerates the proliferation and invasion of hepatocellular carcinoma cells by sponging the micro RNA-124 or micro RNA-506/pyruvate dehydrogenase kinase 2 axis

Circular RNAs (circRNAs) have been confirmed to be associated with the progression of various cancers, including hepatocellular carcinoma (HCC). However, the role and mechanism of circHIPK3 in HCC are still unclear. To investigate its function, circHIPK3 expression was first determined by RT–qPCR in HCC tissues or cells. Functionally, cell proliferation and invasion were investigated by CCK-8, EdU, or Transwell assays. In terms of understanding the mechanism, the interaction of the circRNA HIPK3/micro RNA 124 (miRNA 124) or micro RNA 506 (miRNA506) /PDK2 regulatory loop was verified by dual-luciferase reporter gene assay. In addition, a xenograft tumor model was established to confirm the impact of circHIPK3 on the growth of HCC cells in vivo. We found that circHIPK3 was upregulated in HCC patients and associated with clinical characteristics, while miR-124 and miR-506 were downregulated in HCC patients. Additionally, we proved that knock down of circHIPK3 remarkably suppressed the proliferation and invasion of HCC cells. Mechanistically, circHIPK3 directly bound to miR-124 or miR-506 and inhibited their expression, and PDK2 was a target gene of miR-124 or miR-506. Moreover, circHIPK3 overexpression reversed the inhibitory effect of miR-124 or miR-506 on HCC progression. miR-124 or miR-506 could also suppress tumorigenesis of HCC cells by PDK2. Furthermore, in vivo evidence confirmed that knock down of circHIPK3 inhibited tumor formation. We suggest that circHIPK3 can accelerate the proliferation and invasion of HCC cells by sponging miR-124 or miR-506 to upregulate PDK2, which is the underlying mechanism of circHIPK3-induced HCC progression.

Circular RNA circHIPK3 is downregulated in diabetic cardiomyopathy and overexpression of circHIPK3 suppresses PTEN to protect cardiomyocytes from high glucose-induced cell apoptosis

It has been reported that circHIPK3 can be downregulated by high glucose, suggesting its potential involvement in diabetes and diabetic complications. This study aimed to explore the role of circHIPK3 in diabetic cardiomyopathy (DC). PTEN is a kind of tumor suppressor gene, which is very commonly lost in human cancer. We detected the expression of circHIPK3 and PTEN in plasma samples from DC patients, diabetic patients without complications diabetes mellitus (DM) and health controls by RT-qPCR and ELISA. In vitro cell experiment, AC16 cells (cardiomyocytes) were treated with high glucose, followed by expression analysis of circHIPK3 and PTEN mRNA by RT-qPCR. CircHIPK3 or PTEN expression vector were used to overexpress circHIPK3 and PTEN in AC16 cells to explore the relationship between them. The role of circHIPK3 and PTEN in regulating the apoptosis of AC16 cells was analyzed by cell apoptosis assay. The result showed that CircHIPK3 was downregulated in diabetes and further downregulated in DC. In AC16 cells, high glucose treatment decreased the expression levels of circHIPK3. Across DC samples, the expression of circHIPK3 was inversely correlated with PTEN. In AC16 cells, overexpression of circHIPK3 decreased the expression levels of PTEN. CircHIPK3 may suppress AC16 cell apoptosis induced by high glucose and inhibited the role of PTEN in cell apoptosis. Therefore, circHIPK3 may downregulate PTEN to protect cardiomyocytes from high glucose-induced cell apoptosis.

Circular RNA HIPK3 aggravates sepsis-induced acute kidney injury via modulating the microRNA-338/forkhead box A1 axis

Circular RNAs (circRNAs) have been extensively studied in various diseases, including sepsis-induced acute kidney injury (AKI). This research intended to elucidate the mechanism of circular RNA HIPK3 (circHIPK3) in sepsis-engendered AKI. Human tubule epithelial cells (HK2) were stimulated with lipopolysaccharide (LPS) to establish a septic AKI cell model. The gene expression levels were evaluated by RT-qPCR. Cell viability, apoptosis, and cell cycle distribution were assessed through CCK-8 and flow cytometry assays. The potential interactions between genes were verified by luciferase reporter and RIP assays. The results displayed that circHIPK3 expression was enhanced in septic AKI patients and LPS-triggered HK2 cells. Moreover, circHIPK3 interference expedited HK2 cell viability and attenuated apoptosis, inflammatory and oxidative damages following LPS stimulation. Furthermore, circHIPK3 functioned as a molecular sponge for miR-338, and forkhead box A1 (FOXA1) was negatively regulated by miR-338. CircHIPK3 aggravated cell injury in LPS-treated HK2 via targeting miR-338, and FOXA1 addition overturned the suppressing impacts of miR-338-3p augmentation on LPS-activated HK2 cell damage. Finally, we demonstrated that circHIPK3 modulated LPS-induced cell damage via the miR-338/FOXA1 axis. In sum, our results elaborated that circHIPK3 knockdown attenuated LPS-triggered HK2 cell injury by regulating FOXA1 expression via interacting with miR-338, suggesting that circHIPK3 might be a potential biomarker and therapeutic target for sepsis-induced AKI patients.

Construction and Comprehensive Analysis of a circRNA-miRNA-mRNA Regulatory Network to Reveal the Pathogenesis of Hepatocellular Carcinoma

Background: Circular RNAs (circRNAs) have been demonstrated to be closely related to the carcinogenesis of human cancer in recent years. However, the molecular mechanism of circRNAs in the pathogenesis of hepatocellular carcinoma (HCC) has not been fully elucidated. We aimed to identify critical circRNAs and explore their potential regulatory network in HCC.

Methods: The robust rank aggregation (RRA) algorithm and weighted gene co-expression network analysis (WGCNA) were conducted to unearth the differentially expressed circRNAs (DEcircRNAs) in HCC. The expression levels of DEcircRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). A circRNA-miRNA-mRNA regulatory network was constructed by computational biology, and protein-protein interaction (PPI) network, functional enrichment analysis, survival analysis, and infiltrating immune cells analysis were performed to uncover the potential regulatory mechanisms of the network.

Results: A total of 22 DEcircRNAs were screened out from four microarray datasets (GSE94508, GSE97332, GSE155949, and GSE164803) utilizing the RRA algorithm. Meanwhile, an HCC-related module containing 404 circRNAs was identified by WGCNA analysis. After intersection, only four circRNAs were recognized in both algorithms. Following qRT-PCR validation, three circRNAs (hsa_circRNA_091581, hsa_circRNA_066568, and hsa_circRNA_105031) were chosen for further analysis. As a result, a circRNA-miRNA-mRNA network containing three circRNAs, 17 miRNAs, and 222 mRNAs was established. Seven core genes (ESR1, BUB1, PRC1, LOX, CCT5, YWHAZ, and DDX39B) were determined from the PPI network of 222 mRNAs, and a circRNA-miRNA-hubgene network was also constructed. Functional enrichment analysis suggested that these seven hub genes were closely correlated with several cancer related pathways. Survival analysis revealed that the expression levels of the seven core genes were significantly associated with the prognosis of HCC patients. In addition, we also found that these seven hub genes were remarkably related to the infiltrating levels of immune cells.

Conclusion: Our research identified three pivotal HCC-related circRNAs and provided novel insights into the underlying mechanisms of the circRNA-miRNA-mRNA regulatory network in HCC.

MicroRNAs and the DNA damage response: How is cell fate determined?

It is becoming clear that the DNA damage response orchestrates an appropriate response to a given level of DNA damage, whether that is cell cycle arrest and repair, senescence or apoptosis. It is plausible that the alternative regulation of the DNA damage response (DDR) plays a role in deciding cell fate following damage. MicroRNAs (miRNAs) are associated with the transcriptional regulation of many cellular processes. They have diverse functions, affecting, presumably, all aspects of cell biology. Many have been shown to be DNA damage inducible and it is conceivable that miRNA species play a role in deciding cell fate following DNA damage by regulating the expression and activation of key DDR proteins. From a clinical perspective, miRNAs are attractive targets to improve cancer patient outcomes to DNA-damaging chemotherapy. However, cancer tissue is known to be, or to become, well adapted to DNA damage as a means of inducing chemoresistance. This frequently results from an altered DDR, possibly owing to miRNA dysregulation. Though many studies provide an overview of miRNAs that are dysregulated within cancerous tissues, a tangible, functional association is often lacking. While miRNAs are well-documented in 'ectopic biology', the physiological significance of endogenous miRNAs in the context of the DDR requires clarification. This review discusses miRNAs of biological relevance and their role in DNA damage response by potentially 'fine-tuning' the DDR towards a particular cell fate in response to DNA damage. MiRNAs are thus potential therapeutic targets/strategies to limit chemoresistance, or improve chemotherapeutic efficacy.

A curcumin analog GL63 inhibits the malignant behaviors of hepatocellular carcinoma by inactivating the JAK2/STAT3 signaling pathway via the circular RNA zinc finger protein 83/microRNA-324-5p/cyclin-dependent kinase 16 axis

BACKGROUND AND AIM

(1E,4E)-1,5-bis(2-bromophenyl) penta-1,4-dien-3-one (GL63) is a curcumin analog that can protect against carcinogenesis in hepatocellular carcinoma (HCC). The aim of this study was to explore the molecular mechanism of GL63 in HCC.

METHODS

Cell viability was examined by cell counting kit-8 (CCK-8) assay. Circular RNA zinc finger protein 83 (circZNF83), microRNA-324-5p (miR-324-5p), and cyclin-dependent kinase 16 (CDK16) levels were measured via the quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed using colony formation assay. Flow cytometry was performed for detecting cell cycle and apoptosis. Protein analysis was conducted by western blot. Cell migration and invasion were determined using transwell assay. Target relation was analyzed using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The function of GL63 in vivo was researched by xenograft model in mice.

RESULTS

GL63 inhibited the circZNF83 expression in HCC cells. CircZNF83 overexpression attenuated the inhibitory effects of GL63 on HCC cell growth, cell cycle progression, migration, and invasion but the promoting effect on cell apoptosis. CircZNF83 served as a sponge of miR-324-5p and circZNF83/miR-324-5p axis was involved in the functional regulation of GL63 in HCC progression. Moreover, CDK16 was a downstream target of miR-324-5p and circZNF83 could regulate the CDK16 expression by sponging miR-324-5p. The anti-tumor function of GL63 was also related to the miR-324-5p/CDK16 axis. In addition, GL63 inactivated the JAK2/STAT3 pathway via downregulating circZNF83 to mediate the miR-324-5p/CDK16 axis. GL63 also repressed tumor growth in vivo through the circZNF83/miR-324-5p/CDK16-mediated JAK2/STAT3 signal inhibition.

CONCLUSION

This study suggested GL63 impeded the HCC development by blocking the JAK2/STAT3 signaling pathway via mediating the circZNF83/miR-324-5p/CDK16 axis.

Circ_0007031 Silencing Inhibits Cell Proliferation and Induces Cell Apoptosis via Downregulating MELK at a miR-485-3p-Dependent Way in Colorectal Cancer

Colorectal cancer (CRC) is a malignant cancer with an increasing incidence. Circular RNA (circRNA) is recently found to participate in the regulation of CRC progression. However, the role of circ_0007031 in CRC malignant progression remains elusive. 50 CRC patients were implicated in this study. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the RNA expression of circ_0007031, microRNA-485-3p (miR-485-3p) and maternal embryonic leucine zipper kinase (MELK). Western blot analysis was conducted to determine protein expression. Cell viability and proliferation were demonstrated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine (EdU) assays, respectively. Cell cycle and apoptosis were investigated by flow cytometry analysis. The interaction among circ_0007031, miR-485-3p and MELK was predicted by online databases, and identified by dual-luciferase reporter assay. Mouse model assay was conducted to reveal the effect of circ_0007031 on tumor formation in vivo. Circ_0007031 and MELK expression were obviously increased, while miR-485-3p expression was decreased in CRC tissues and cells compared with normal colorectal tissues or cells. Circ_0007031 knockdown repressed proliferation, whereas induced cell arrest at G0/G1 phase and apoptosis. On the opposite, circ_0007031 overexpression promoted cell proliferation and induced cell arrest at S phase. Additionally, miR-485-3p inhibitors attenuated circ_0007031 silencing-mediated CRC cell malignancy. MiR-485-3p was unveiled to regulate CRC cell processes via targeting MELK. Circ_0007031 controlled MELK expression via interacting with miR-485-3p. Furthermore, circ_0007031 contributed to tumor formation in vivo. Circ_0007031 knockdown repressed CRC malignant progression by reducing MELK expression through associating with miR-485-3p, suggesting that circ_0007031 was a potential target for the therapy of CRC.

A Novel circRNA-miRNA-mRNA Hub Regulatory Network in Lung Adenocarcinoma

The growing evidence suggests that circular RNAs (circRNAs) have significant associations with tumor occurrence and progression, yet the regulatory mechanism of circRNAs in lung adenocarcinoma (LUAD) remains unclear. This study clarified the potentially regulatory network and functional mechanism of circRNAs in LUAD. The expression data of circRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) were obtained from the Gene Expression Omnibus (GEO) database. Relying on GSE101586, GSE101684, and GSE112214, we identified differentially expressed circRNAs (DEcircRNAs). Depending on GSE135918 and GSE32863, we screened out differentially expressed miRNAs (DEmiRNAs) and mRNAs (DEmRNAs), respectively. Then, a novel competing endogenous RNA (ceRNA) regulatory network related to LUAD was constructed. We also revealed biological processes and signal pathways regulated by these DEcircRNAs. Based on gene expression data and survival information of LUAD patients in The Cancer Genome Atlas (TCGA) and GEO, we implemented survival analysis to select DEmRNAs related to prognosis and build a novel circRNA-miRNA-mRNA hub regulatory network. Meanwhile, quantitative real-time PCR (qRT-PCR) was utilized to validate DEcircRNAs in the ceRNA hub regulatory network. As a result, a total of 8 DEcircRNAs, 19 DEmiRNAs, and 85 DEmRNAs were identified. The novel ceRNA regulatory network included 5 circRNAs, 8 miRNAs, and 22 mRNAs. The final ceRNA hub regulatory network contained two circRNAs, two miRNAs, and two mRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that the five DEcircRNAs may affect LUAD onset and progression through Wnt signaling pathway and Hippo signaling pathway. All in all, this study revealed the regulatory network and functional mechanism of circRNA-related ceRNAs in LUAD.

Biogenesis, cellular effects, and biomarker value of circHIPK3

Competing endogenous RNAs (ceRNAs) can indirectly regulate gene expression by competitively binding to microRNA(miRNA) through miRNA response elements (MREs) to affect miRNA-induced gene regulation, which is of great biological significance. Among them, circular RNA (circRNA) has become a hotspot due to its highest binding capacity. A specific circRNA discussed in this review, circHIPK3, has been studied for its biological characteristics, function, cellular effects and its relationship with tumors and various diseases. Here, we review the recent researches about circHIPK3 in detail and aim to elucidate accurate conclusions from them. These circHIPK3-miRNAs-mRNA pathways will further advance the application of circHIPK3 in diseases development, early diagnosis and gene targeting therapy.

Emerging landscape of circHIPK3 and its role in cancer and other diseases (Review)

Circular RNAs (circRNAs) are a special class of recently re‑discovered RNAs, which are covalently closed ring RNA molecules. circRNAs have been reported to possess multiple functions and are considered crucial regulators of several processes, and are therefore gaining increasing attention. In recent years, increasing evidence has shown that circRNAs are implicated in several crucial biological processes via regulation of gene expression, and their dysregulation is also associated with the development of numerous diseases, particularly acting as oncogenic or tumor‑suppressor molecules in cancer. Furthermore, circRNAs are involved in cell proliferation, differentiation, apoptosis, invasion and metastasis. In the present review, the biogenesis and functions of circRNAs are described, with a focus on the most recent research advances and the emerging roles of circular homeodomain‑interacting protein kinase 3 (circHIPK3) in human diseases. The present review may provide novel avenues for research on the roles of circHIPK3 as a clinical diagnostic and prognostic biomarker, as well as highlighting promising therapeutic targets for certain diseases and cancer.

Circ_HIPK3 alleviates CoCl2-induced apoptotic injury in neuronal cells by depending on the regulation of the miR-222-3p/DUSP19 axis

Circular RNA (circRNA) homeodomain-interacting protein kinase 3 (circ_HIPK3) has recently reported as regulator in spinal cord injury (SCI). The regulatory mechanism of circ_HIPK3 in SCI was further researched in this study. Circ_HIPK3 expression was inhibited by CoCl₂ in AGE1.HN cells. The CoCl₂-induced cell cycle arrest, cell proliferation inhibition and apoptosis promotion were mitigated by overexpression of circ_HIPK3. Circ_HIPK3 could target miR-222-3p and circ_HIPK3 repressed the CoCl₂-induced neuronal cell injury by sponging miR-222-3p. DUSP19 was a target gene of miR-222-3p and circ_HIPK3 affected the expression of DUSP19 via binding to miR-222-3p. The regulation of circ_HIPK3 in CoCl₂-induced injury of AGE1.HN cells was associated with the upregulation of DUSP19. Circ_HIPK3 acted as a pathogenic inhibitor in the progression of SCI via the miR-222-3p-mediated DUSP19 upregulation.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

CircHIPK3: Key Player in Pathophysiology and Potential Diagnostic and Therapeutic Tool

A large number of studies in China and other countries have confirmed that circularHIPK3 (circHIPK3) plays an important role in the pathophysiological processes of various diseases. Through the action of sponge miRNA (miR), circHIPK3 regulates cell proliferation, differentiation, and migration, and plays a key role in disease processes. By referring to a large number of research reports, this article explores the specific functional role of circHIPK3 in fibrotic diseases, cancer, and other diseases. This review aims to clarify the role of circHIPK3 in disease processes in order to aid further studies into the specific pathogenesis and clinical diagnosis of various diseases and provide new ideas for treatments.

CircHIPK3 Alleviates High Glucose Toxicity to Human Renal Tubular Epithelial HK-2 Cells Through Regulation of miR-326/miR-487a-3p/SIRT1

BACKGROUND

The intervention of circular RNA HIPK3 (circHIPK3) in diabetes has drawn increasing attention in recent years. However, the underlying mechanism of circHIPK3 in diabetic nephropathy (DN) has not been fully elucidated. Thus, the current study aims to investigate the role of circHIPK3 in high glucose (HG)-induced toxicity to human renal tubular epithelial HK-2 cells.

METHODS

The expression of circHIPK3 in HK-2 cells induced by HG was determined by qRT-PCR and Western blot. The regulatory effects of circHIPK3 and miR-326/miR-487a-3p on cells proliferative and apoptosis were evaluated by CCK-8 and flow cytometry. Dual-luciferase reporter assay was applied to predict the target genes of miR-326 or miR-487a-3p.

RESULTS

Expression level of circHIPK3 in HK-2 cells was remarkably decreased after the treatment of HG. The overexpression of circHIPK3 effectively reversed the HG-induced HK-2 cell proliferation inhibition and apoptosis. Furthermore, SIRT1 was confirmed to be the target gene of miR-326 and miR-487a-3p, which were showed to be the downstream genes of circHIPK3. The silencing of miR-326 or miR-487a-3p was also proved to induce proliferation and reduce apoptosis in HG-induced HK-2 cells.

CONCLUSION

Our data suggest that overexpression of circHIPK3 can attenuate the proliferation inhibition of HK-2 induced by HG and inhibit apoptosis through sponging miR-326 or miR-487a-3p to regulate SIRT1.

Circ-CCS is identified as a cancer-promoting circRNA in lung cancer partly by regulating the miR-383/E2F7 axis

BACKGROUND

Increasing biomolecules have been found to be involved in the lung cancer development. This study will perform the function and mechanism analyses of a novel circular RNA copper chaperone for superoxide dismutase (circ-CCS) in lung cancer.

METHODS

Circ-CCS, microRNA-383 (miR-383) and E2F transcription factor 7 (E2F7) were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was detected using Cell Counting Kit-8 (CCK-8). Clonal ability was measured by colony formation assay. Cell apoptosis was determined via flow cytometry. Cell migration and invasion were assessed by transwell assay. Detection of protein was completed using western blot. Xenograft assay was used for the functional analysis of circ-CCS in vivo. The binding between targets was proved by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. E2F7 protein level was also examined by Immunohistochemistry (IHC) analysis in human tissues.

RESULTS

Circ-CCS was upregulated in lung cancer and could predict poor prognosis. Downregulation of circ-CCS inhibited lung cancer cell growth and metastasis while promoted apoptosis in vitro, and suppressed tumorigenesis of lung cancer in vivo. Circ-CCS had sponge effect on miR-383 and the function of si-circ-CCS was achieved by upregulating miR-383. E2F7 was a target gene of miR-383 and its downregulation was responsible for the anti-cancerous role of miR-383 in lung cancer. Circ-CCS could elevate E2F7 expression via interacting with miR-383.

CONCLUSION

Circ-CCS was shown to facilitate lung cancer progression via the miR-383/E2F7 axis, exhibiting the pivotal value of circ-CCS in diagnosis and treatment of lung cancer.

Decreased MiR-485-5p Contributes to Inflammatory Pain Through Post-Transcriptional Upregulation of ASIC1 in Rat Dorsal Root Ganglion

Background

Inflammatory pain is the most common type of pain treated clinically. However, the currently available treatments for inflammatory pain have limited effects and can cause severe side effects. The aim of this study is to describe the effect of miRNA-485-5p on osteoarthritis-related inflammatory pain.

Methods

Paw withdrawal threshold (PWT) of rats was measured by von Frey filaments. The expressions of miRNA-485-5p and acid-sensing ion channel 1 (ASIC1) in the dorsal root ganglion (DRG) were measured with real-time quantitative PCR and Western blotting analysis. Fluorescent in situ hybridization and fluorescent immunohistochemistry were employed to detect expression of miRNA-485-5p, acid-sensing ion channelASIC1 and co-location of miRNA-485-5p with ASIC1.

Results

The PWT of rats was significantly reduced after complete Freund's adjuvant (CFA) injection. The miRNA-485-5p expression level clearly decreased while the ASIC1 expression level was upregulated in the L4-6 dorsal root ganglion (DRG) of CFA rats. MiRNA-485-5p and ASIC1 were co-expressed in the same DRG cells of CFA rats. Amiloride, an inhibitor of ASIC1, clearly increased the PWT of CFA rats. Further, miRNA-485-5p agomir reversed the upregulation of ASICI1 and alleviated CFA-induced mechanical hypersensitivity of CFA rats.

Conclusion

These results suggest that reduced expression of miRNA-485-5p contributes to inflammatory pain through upregulating ASIC1 expression, implying a promising strategy for pain therapy.

CircHIPK3: a promising cancer-related circular RNA

Circular RNA (circRNA) is a special type of endogenous noncoding RNAs (ncRNAs), and are characterized by a covalently closed loop structure without a 5' cap and poly-adenylated tails. Abnormal expression of circRNAs has been implicated in a wide range of human cancers, where they function as either tumor suppressor genes or oncogenes. CircHIPK3, circRNA homeodomain-interacting protein kinase 3, is associated with human cancers such as lung cancer, bladder cancer, hepatocellular carcinoma, colorectal cancer, osteosarcoma, glioma and prostate cancer, et al. Numerous studies have indicated that circHIPK3 functions as a miRNA sponge to regulate the target genes and exert specific biological effects, including regulation of cell proliferation, invasion, and migration. Furthermore, circHIPK3 is thought to be a novel diagnostic biomarker, therapeutic target, and prognostic biomarker in different cancer types. Here, we reviewed the recent progress of the mechanism and functions of circHIPK3 during the evolution of malignancies.