Circular RNA circPLK1 promotes breast cancer cell proliferation, migration and invasion by regulating miR-4500/IGF1 axis

Circular RNAs as a novel molecular mechanism in diagnosis, prognosis, therapeutic target, and inhibiting chemoresistance in breast cancer

Breast cancer (BC) is the most common cancer among women, characterized by significant heterogeneity. Diagnosis of the disease in the early stages and appropriate treatment plays a crucial role for these patients. Despite the available treatments, many patients due to drug resistance do not receive proper treatments. Recently, circular RNAs (circRNAs), a type of non-coding RNAs (ncRNAs), have been discovered to be involved in the progression and resistance to drugs in BC. CircRNAs can promote or inhibit malignant cells by their function. Numerous circRNAs have been discovered to be involved in the proliferation, invasion, and migration of tumor cells, as well as the progression, pathogenesis, tumor metastasis, and drug resistance of BC. Circular RNAs can also serve as a biomarker for diagnosing, predicting prognosis, and targeting therapy. In this review, we present an outline of the variations in circRNAs expression in various BCs, the functional pathways, their impact on the condition, and their uses in clinical applications.

Adipocytes promote metastasis of breast cancer by attenuating the FOXO1 effects and regulating copper homeostasis

BACKGROUND

Obesity and the forkhead box O1(FOXO1) affect the survival of breast cancer patients, but the underlying mechanism remains unclear. We aimed to investigate the role of FOXO1 in obesity-associated-breast cancer.

METHODS

We screened 383 breast disease patients from the first affiliated hospital with Nanjing Medical University in 2020. We performed wound healing, transwell, matrigel assays to assess the metastatic ability of cancer cells. We adopted mRNAs sequencing to select the differentially expressed transcripts in breast cancer. We applied immunohistochemistry, western blot, tissue microarrays to assess the level of FOXO1 and epithelial-mesenchymal transition (EMT) pathways. We conducted bioinformatic analysis to investigate interactions between FOXO1 and miR-135b. We used fluorescence in situ hybridization, RT-qPCR to confirm the characteristics of circCNIH4. We conducted luciferase reporter assay, rescue experiments to investigate interactions between circCNIH4 and miR-135b.

RESULTS

Obesity was positively correlated with the incidence and progression of breast cancer. Adipocytes enhanced the migration of breast cancer and attenuated the effects of FOXO1. MiR-135b was a binding gene of FOXO1 and was regulated by circCNIH4. CircCNIH4 exhibited antitumor activity in vitro and in vivo.

CONCLUSION

Adipocytes might accelerate the progression of breast cancer by modulating FOXO1/miR-135b/ circCNIH4 /EMT axis and regulating copper homeostasis.

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

Circular RNA-mediated miRNA sponge & RNA binding protein in biological modulation of breast cancer

Circular RNAs (circRNAs) and small non-coding RNAs of the head-to-junction circle in the construct play critical roles in gene regulation and are significantly associated with breast cancer (BC). Numerous circRNAs are potential cancer biomarkers that may be used for diagnosis and prognosis. Widespread expression of circRNAs is regarded as a feature of gene expression in highly diverged eukaryotes. Recent studies show that circRNAs have two main biological modulation models: sponging and RNA-binding. This review explained the biogenesis of circRNAs and assessed emerging findings on their sponge function and role as RNA-binding proteins (RBPs) to better understand how their interaction alters cellular function in BC. We focused on how sponges significantly affect the phenotype and progression of BC. We described how circRNAs exercise the translation functions in ribosomes. Furthermore, we reviewed recent studies on RBPs, and post-protein modifications influencing BC and provided a perspective on future research directions for treating BC.

Regulatory miRNAs, circRNAs and lncRNAs in cell cycle progression of breast cancer

Breast cancer is a complex and heterogeneous disease that poses a significant public health concern worldwide, and it remains a major challenge despite advances in treatment options. One of the main properties of cancer cells is the increased proliferative activity that has lost regulation. Dysregulation of various positive and negative modulators in the cell cycle has been identified as one of the driving factors of breast cancer. In recent years, non-coding RNAs have garnered much attention in the regulation of cell cycle progression, with microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) being of particular interest. MiRNAs are a class of highly conserved and regulatory small non-coding RNAs that play a crucial role in the modulation of various cellular and biological processes, including cell cycle regulation. CircRNAs are a novel form of non-coding RNAs that are highly stable and capable of modulating gene expression at posttranscriptional and transcriptional levels. LncRNAs have also attracted considerable attention because of their prominent roles in tumor development, including cell cycle progression. Emerging evidence suggests that miRNAs, circRNAs and lncRNAs play important roles in the regulation of cell cycle progression in breast cancer. Herein, we summarized the latest related literatures in breast cancer that emphasize the regulatory roles of miRNAs, circRNAs and lncRNAs in cell cycle progress of breast cancer. Further understanding of the precise roles and mechanisms of non-coding RNAs in breast cancer cell cycle regulation could lead to the development of new diagnostic and therapeutic strategies for breast cancer.

Circ_0102543 suppresses hepatocellular carcinoma progression through the miR-942-5p/SGTB axis

Introduction

Hepatocellular carcinoma (HCC) is one of the most serious cancers. Circular RNA (circRNA) has been reported to regulate the progression of HCC. Herein, the role of circ_0102543 in HCC tumorigenesis was investigated.

Materials

The expression levels of circ_0102543, microRNA-942-5p (miR-942-5p), and small glutamine rich tetratricopeptide repeat co-chaperone beta (SGTB) were detected by quantitative real-time PCR (qRT-PCR). 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide (MTT) assay, thymidine analog 5-ethynyl-2'-deoxyuridine (EDU) assay, transwell assay, and flow cytometry were conducted to explore the function of circ_0102543 in HCC cells and the regulatory mechanism among circ_0102543, miR-942-5p and SGTB in HCC cells. Western blot examined the related protein levels.

Results

The expression of circ_0102543 and SGTB was decreased in HCC tissues, while the expression of miR-942-5p was increased. Circ_0102543 acted as a sponge for miR-942-5p, and SGTB was the target of miR-942-5p. Circ_0102543 up-regulation hindered tumor growth in vivo. In vitro experiments showed that overexpression of circ_0102543 significantly repressed the malignant behaviors of HCC cells, while co-transfection of miR-942-5p partially attenuated these effects mediated by circ_0102543. In addition, SGTB knockdown increased the proliferation, migration, and invasion of HCC cells inhibited by miR-942-5p inhibitor. Mechanically, circ_0102543 regulated SGTB expression in HCC cells by sponging miR-942-5p.

Conclusion

Overexpression of circ_0102543 suppressed proliferation, migration, and invasion of HCC cells by regulating the miR-942-5p/SGTB axis, suggesting that circ_0102543/miR-942-5p/SGTB axis may be a potential therapeutic target for HCC.

Hsa_circ_0003220 Drives Chemoresistance of Human NSCLC Cells by Modulating miR-489-3p/IGF1

Circular RNAs (circRNAs) have been shown to have critical roles in developing cancer and treatment resistance in an increasing body of research. The aim was to look into the functions and processes of hsa_circ_0003220 in the non-small cell lung cancer (NSCLC) chemoresistance. The NSCLC cell lines H460 and A549 were employed in present work. hsa_circ_0003220, miR-489-3p, and insulin-like growth factors (IGF1) mRNA levels were assessed with a quantitative real time polymerase chain reaction (qRT-PCR). The cisplatin, docetaxel, and paclitaxel (PTX) resistances were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the enzyme linked immunosorbent assay (ELISA) test measured IGF1 expression. In order to corroborate the miR-489-3p relation with hsa_circ_0003220 or IGF1, a dual-luciferase reporter method was applied. The level of hsa_circ_0003220 was raised in cells and tissues from PTX-resistant (PR) NSCLC. In PR NSCLC cells, hsa_circ_0003220 knockdown reduced chemoresistance. For the purpose of the mechanism study, hsa_circ_0003220 knockdown substantially reduced IGF1 expression via miR-489-3p sponging, reducing chemoresistance in PR NSCLC cells. By controlling the miR-489-3p/IGF1 axis, hsa_circ_0003220 knockdown helped NSCLC overcome chemoresistance, suggesting a potential circRNA-targeted therapy for the disease.

The Tumorigenic Role of Circular RNA-MicroRNA Axis in Cancer

Circular RNAs (circRNAs) are a class of endogenous RNAs that control gene expression at the transcriptional and post-transcriptional levels. Recent studies have increasingly demonstrated that circRNAs act as novel diagnostic biomarkers and promising therapeutic targets for numerous cancer types by interacting with other non-coding RNAs such as microRNAs (miRNAs). The miRNAs are presented as crucial risk factors and regulatory elements in cancer by regulating the expression of their target genes. Some miRNAs are derived from transposable elements (MDTEs) that can transfer their location to another region of the genome. Genetic interactions between miRNAs and circular RNAs can form complex regulatory networks with various carcinogenic processes that play critical roles in tumorigenesis and cancer progression. This review focuses on the biological regulation of the correlative axis among circular RNAs, miRNAs, and their target genes in various cancer types and suggests the biological importance of MDTEs interacting with oncogenic or tumor-suppressive circRNAs in tumor progression.

Circular RNAs Involved in the Regulation of the Age-Related Pathways

Circular RNAs (circRNAs) are a class of covalently circular noncoding RNAs that have been extensively studied in recent years. Aging is a process related to functional decline that is regulated by signal transduction. An increasing number of studies suggest that circRNAs can regulate aging and multiple age-related diseases through their involvement in age-related signaling pathways. CircRNAs perform several biological functions, such as acting as miRNA sponges, directly interacting with proteins, and regulating transcription and translation to proteins or peptides. Herein, we summarize research progress on the biological functions of circRNAs in seven main age-related signaling pathways, namely, the insulin-insulin-like, PI3K-AKT, mTOR, AMPK, FOXO, p53, and NF-κB signaling pathways. In these pathways, circRNAs mainly function as miRNA sponges. In this review, we suggest that circRNAs are widely involved in the regulation of the main age-related pathways and are potential biomarkers for aging and age-related diseases.

Circ0038632 modulates MiR-186/DNMT3A axis to promote proliferation and metastasis in osteosarcoma

Osteosarcoma is a highly malignant solid tumor with poor prognosis, early metastasis, and rapid progression and has a high mortality rate, in which better therapeutic strategies are needed. Circ0038632, also known as circPLK1, is a tumor promotor in multiple cancers. However, its biological functions and molecular regulatory mechanisms in osteosarcoma remain unclear. To ascertain the function of circ0038632 in osteosarcoma, we checked its expression in cells and in tissues and tested its abilities of proliferation and migration. Expression experiment manifested that circ0038632 showed an enhanced expression in osteosarcoma. Functional studies revealed that circ0038632 inhibition reduced cell proliferation and metastasis abilities of osteosarcoma. Mechanism studies revealed that circ0038632 sponged miR-186 to upregulate the expression of DNA methyltransferase 3A (DNMT3A) to promote osteosarcoma progression. The circ0038632/miR-186/DNMT3A axis was involved in osteosarcoma progression. The results elucidated the potential application of circ0038632 as a novel diagnostic biomarker for progressive process of osteosarcoma.

Profiling and functional analysis of differentially expressed circular RNAs identified in foot-and-mouth disease virus infected PK-15 cells

Circular RNAs (circRNAs) are a new type of endogenous noncoding RNA that exhibit a variety of biological functions. However, it is not clear whether they are involved in foot-and-mouth disease virus (FMDV) infection and host response. In this study, we established circRNA expression profiles in FMDV-infected PK-15 cells using RNA-seq (RNA-sequencing) technology analysis. The biological function of the differentially expressed circRNAs was determined by protein interaction network, Gene Ontology (GO), and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment. We found 1100 differentially expressed circRNAs (675 downregulated and 425 upregulated) which were involved in various biological processes such as protein ubiquitination modification, cell cycle regulation, RNA transport, and autophagy. We also found that circRNAs identified after FMDV infection may be involved in the host cell immune response. RNA-Seq results were validated by circRNAs qRT-PCR. In this study, we analyzed for the first time circRNAs expression profile and the biological function of these genes after FMDV infection of host cells. The results provide new insights into the interactions between FMDV and host cells.

Circ_0078710 promotes the development of liver cancer by upregulating TXNDC5 via miR-431-5p

INTRODUCTION AND OBJECTIVES

Liver cancer, with high recurrence and metastasis rate, is a common malignant tumor. Circular RNA_0078710 (circ_0078710) has been shown to be take part in the advance of hepatocellular carcinoma. However, the interaction between circ_0091579 and microRNA-431-5p (miR-431-5p) in liver cancer has not been studied.

MATERIALS AND METHODS

The expressions of circ_0078710, miR-431-5p and Thioredoxin domain-containing 5 (TXNDC5) in liver cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The effect of cric_0078710 in liver cancer cells was assessed by Cell Counting Kit-8 (CCK-8) assay, Transwell, flow cytometry and Dual-luciferase reporter assay. Glycolysis metabolism was examined by lactate production, glucose uptake and ATP level. The protein levels of ki-67, bax and TXNEC5 were tested by western blot. The role of circ_0078710 in vivo was determined by animal study.

RESULTS

Circ_0078710 and TXNDC5 were notably expressed in liver cancer tissues and cells. Circ_0078710 knockdown diminished proliferation, migration, invasion and glycolytic metabolism of huh7 and Hep3B cells, and accelerated cell apoptosis. MiR-431-5p is the target of circ_0078710, and silence circ_0078710 can inhibit the malignant behavior and glycolysis of hepatocellular carcinoma (HCC) cells by releasing miR-431-5p. In addition, TXNDC5 was a target of miR-431-5p, and overexpression of TXNDC5 restored cell proliferation and glycolysis inhibition due to miR-431-5p. Animal experiments made clear the anti-tumor effect of circ_0078710 knockdown.

CONCLUSION

Circ_0078710 promotes the progression of liver cancer by regulating TXNDC5 expression by targeting miR-431-5p. These results demonstrate that circ_0078710 could be a remedy target for liver cancer.

circKL inhibits the growth and metastasis of kidney cancer by sponging miR‑182‑5p and upregulating FBXW7

Circular RNAs (circRNAs) are a type of non-coding RNA with important roles in the regulation of various biological processes involved in malignant progression. However, the potential molecular mechanisms and roles of circRNAs in kidney cancer have remained to be fully elucidated. In a previous study by our group, high-throughput microarray sequencing data were analyzed to determine the differentially expressed circRNAs in kidney cancer. In this analysis, a novel circRNA (hsa_circ_0100312, named circKL) was identified as a frequently downregulated circRNA in kidney cancer cells and tissues by reverse transcription-quantitative PCR. In the present study, Cell Counting Kit-8, colony formation, Transwell, wound-healing and mouse xenograft assays as well as a lung metastasis experiment were performed to confirm the functions of circKL. The experiments confirmed that circKL overexpression significantly inhibited the proliferation, migration, tumor growth and metastasis of kidney cancer both in vitro and in vivo. The potential molecular mechanisms of circKL were investigated by performing dual-luciferase and RNA immunoprecipitation assays. Western blot assays confirmed that overexpression of circKL significantly increased the protein level of F-box and WD repeat domain containing 7 (FBXW7). All results suggested that circKL suppressed the growth and migration of kidney cancer by sponging microRNA (miR)-182-5p and upregulating FBXW7 expression. Overall, the circKL/miR-182-5p/FBXW7 axis was indicated to have a key role in the growth and metastasis of kidney cancer and may be targeted as a novel therapeutic strategy.

Upregulation of exosomal circPLK1 promotes the development of non-small cell lung cancer through the miR-1294/ high mobility group protein A1 axis

CircRNAs (circular RNAs) have been implicated in the development and progression of a variety of cancers. The molecular pathways underlying the progression of NSCLC (Non-Small Cell Lung Cancer) and the associated regulation of circRNAs in NSCLC remain to be fully elucidated. In this study, we found that circPLK1 expression was upregulated in serum exosomes and tissues from NSCLC patients. The Kaplan–Meier survival analysis revealed that a high expression level of circPLK1 was associated with a poorer prognosis in NSCLC patients. Exosomes extracted from NSCLC serum could promote the replication, migration, and invasion of NSCLC cells and suppress apoptotic cell death. The overexpression of circPLK1 also promotes the malignant phenotype of NSCLC cells. Molecular analyses demonstrated that circPLK1 directly targets miR-1294 and negatively regulates its activity. And circPLK1 overexpression facilitates the progression of NSCLC by negatively regulating miR-1294 level and maintaining a high-level expression of HMGA1 (High Mobility Group Protein A1). Our study suggests that circPLK1 upregulation plays an important role in NSCLC progression by targeting miR-1294/HMGA1 axis. These data provide a theoretical basis for the development of therapeutic strategy targeting exosomal circPLK1 in NSCLC treatment.

CircPLK1 Acts as a Carcinogenic Driver to Promote the Development of Malignant Pleural Mesothelioma by Governing the miR-1294/HMGA1 Pathway

The deregulation of circular RNAs (circRNAs) is involved in cancer development. CircRNA polo-like kinase 1 (circPLK1) was reported to promote breast cancer development. However, the role of circPLK1 in malignant pleural mesothelioma (MPM) is unclear. The expression of circPLK1, miR-1294, and high mobility group AT-hook 1 (HMGA1) mRNA was measured by quantitative real-time PCR (qPCR). Cell viability was detected by CCK-8 assay. Colony formation ability was monitored by colony formation assay. Cell proliferation was detected by EdU assay. Cell migration and cell invasion were monitored by transwell assay. Cancer cell stemness was investigated by sphere formation assay. The protein levels of marker proteins and HMGA1 expression were measured by western blot analysis. The binding relationship between miR-1294 and circPLK1 or HMGA1 was validated by pull-down assay, dual-luciferase reporter assay or RIP assy. Animal study was performed to disclose the role of circPLK1 in vivo. Exosomes were identified by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). CircPLK1 was upregulated in MPM tumor tissues and cell lines. CircPLK1 knockdown suppressed the proliferation, migration, invasion and stemness of MPM cells. CircPLK1 contained a binding site for miR-1294 and thus bound to miR-1294 to sequester its expression. Inhibition of miR-1294 reversed the effects of circPLK1 knockdown. HMGA1 was a target of miR-1294, and circPLK1 bound to miR-1294 to increase the expression of HMGA1. MiR-1294 restoration also suppressed the proliferation, migration, invasion and stemness of MPM cells, while these effects were abolished by HMGA1 overexpression. In addition, circPLK1 knockdown inhibited tumor growth in vivo. CircPLK1 was overexpressed in exosomes derived from serum of MPM patients. CircPLK1 knockdown inhibited MPM cell proliferation, migration, invasion and stemness by targeting the miR-1294/HMGA1 pathway.

The expression of circ_0090049 in hepatocellular carcinoma and the molecular regulation mechanism of other biological functions

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in liver cancer. Circular RNA_0090049 (circ_0090049) has been shown to be involved in the advance of HCC. However, the interaction between circ_0090049 and microRNA (miRNA) in HCC has not been studied. Quantitative real-time PCR was used to detect the expression of related genes. Through detection of cell proliferation, migration, invasion, and rate of tumor sphere formation, the capping experiment was carried out to verify the regulatory relationship between miRNA and circ_0090049 or circ_0090049 and ubiquitin-conjugating enzyme E2 T (UBE2T). The expression of related proteins was detected by Western blotting. The interaction of miRNA with circ_0090049 or UBE2T was notarized by Dual-luciferase reporter assay. Xenotransplantation experiments confirmed the function of circ_0090049 in vivo. Circ_0090049 and UBE2T were upregulated in liver cancer. Silencing circ_0090049 reduced the proliferation, migration, invasion, and tumor spheroid formation rate of Huh7 and HCCLM3 cells. MiR-605-5p and miR-548c-3p were identified as targets of circ_0090049, and UBE2T was the target of miR-605-5p and miR-548c-3p. Anti-miR-605-5p, anti-miR-548c-3p or UBE2T overexpression restored the inhibitory effect of circ_0090049 knockdown on HCC cells. Animal experiments confirmed the antitumor effect of silence circ_0090049. Circ_0090049 regulates the expression of UBE2T by regulating miR-605-5p or miR-548c-3p, thereby promoting the development of HCC cells.

The Dual Role of Circular RNAs as miRNA Sponges in Breast Cancer and Colon Cancer

Breast cancer (BC) and colon cancer (CRC) are the two most deadly cancers in the world. These cancers partly share the same genetic background and are partially regulated by the same genes. The outcomes of traditional chemoradiotherapy and surgery remain suboptimal, with high postoperative recurrence and a low survival rate. It is, therefore, urgent to innovate and improve the existing treatment measures. Many studies primarily reported that the microRNA (miRNA) sponge functions of circular RNA (circRNA) in BC and CRC have an indirect relationship between the circRNA–miRNA axis and malignant behaviors. With a covalent ring structure, circRNAs can regulate the expression of target genes in multiple ways, especially by acting as miRNA sponges. Therefore, this review mainly focuses on the roles of circRNAs as miRNA sponges in BC and CRC based on studies over the last three years, thus providing a theoretical reference for finding new therapeutic targets in the future.

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.

circRNA-miRNA-mRNA in breast cancer

Among cancers, breast cancer has the highest incidence rate among women and poses a tremendous threat to women's health. Messenger RNA (mRNA), microRNA (miRNA) and circular RNA (circRNA) play vital roles in the progression of breast cancer through a variety of biological effects and mechanisms. Recently, the regulatory network formed by circRNAs, miRNAs and mRNAs has piqued attention and garnered interest. CircRNAs bind to miRNAs through a regulatory mechanism in which endogenous RNAs compete to indirectly regulate the expression of mRNA corresponding to downstream target genes of miRNAs, contributing to the progression of breast cancer. The circRNA-miRNA-mRNA axis may be a marker for the early diagnosis and prognosis of breast cancer and a potential breast cancer treatment target, providing unlimited possibilities for the development of breast cancer biomarkers and therapeutic strategies. This article reviews recent research progress on the circRNA-miRNA-mRNA axis as a regulatory network of competing endogenous RNAs in breast cancer. Herein, we focus on the mechanism and function of the circRNA-miRNA-mRNA axis in the occurrence and metastasis of breast cancer, and resistance to chemotherapy.

circ0093740 Promotes Tumor Growth and Metastasis by Sponging miR-136/145 and Upregulating DNMT3A in Wilms Tumor

As a research hotspot, circular RNAs (circRNAs) is one type of non-coding RNAs which have many different functions in biological processes. However, there is lack of study investigating the underlying molecular mechanism and the potential roles of circRNAs in Wilms tumor. We conducted a high-throughput microarray sequencing to screen differentially expressed circRNAs in Wilms tumor. A novel circRNA (circ0093740) was identified as a frequently upregulated circRNA in Wilms tumor cells and tissues. Suppression of circ0093740 remarkably inhibited the proliferation and migration ability in Wilms tumor, validated by several experiments. The molecular mechanism of circ0093740 was investigated by luciferase assays and RNA immunoprecipitation assays. The results revealed that circ0093740 promotes the growth and migration ability by sponging miR-136/145 and upregulating DNMT3A. In conclusion, our study discovered the biological role of the circ0093740-miR-136/145-DNMT3A axis in Wilms tumor growth and metastasis which is important for developing new treatment strategy.

circ0101675 promotes malignant process via sponging miR-1278 and upregulating WNT3A/5A in non-small cell lung cancer

Circular RNAs (circRNAs) is one type of non-coding RNAs (ncRNAs) which have many roles in biological processes, as well as modulation intracellular gene expression modulation. Nonethless, the roles along with expression status of the most circRNAs in NSCLC (non-small cell lung cancer) remain unknown. Herein, we conducted a high-throughput microarray sequencing to identify abnormal expressed circRNAs. Circ0101675 was found upregulated in NSCLC cell lines and tissues. We carried out colony formation, transwell, CCK-8, and animal assays to investigate the functions of circ0101675. Silence of circ0101675 inhibited the migration and proliferation of NSCLC. To elucidate the mechanism, RNA immunoprecipitation assays along with luciferase enzyme reporter assays were further employed to explore the cross-talk between circ0101675 and other molecules. We discovered that circ0101675 facilitates the malignant process of growth and migration via sponging miR-1278 and upregulating WNT3A/5A expression. In conclusion, we revelaed the vital role of circ0101675-miR-1278-WNT3A/5A signaling in NSCLC progression via the competing endogenous RNAs mechanism. Therefore, circ0101675 can be used as a new and useful biomarker for monitoring and treating NSCLC.