Circular RNA Myosin Light Chain Kinase (MYLK) Promotes Prostate Cancer Progression through Modulating Mir-29a Expression

Prognosis and diagnosis of prostate cancer based on hypergraph regularization sparse least partial squares regression algorithm

BACKGROUND

Prostate cancer (PCa) is a malignant tumor of the male reproductive system, and its incidence has increased significantly in recent years. This study aimed to further identify candidate biomarkers with prognostic and diagnostic significance by integrating gene expression and DNA methylation data from PCa patients through association analysis.

MATERIAL AND METHODS

To this end, this paper proposes a sparse partial least squares regression algorithm based on hypergraph regularization (HR-SPLS) by integrating and clustering two kinds of data. Next, module 2, with the most significant weight, was selected for further analysis according to the weight of each module related to DNA methylation and mRNAs. Based on the DNA methylation sites in module 2, this paper uses multiple machine learning methods to construct a PCa diagnosis-related model of 10-DNA methylation sites.

RESULTS

The results of Receiver Operating Characteristic (ROC) analysis showed that the DNA methylation-related diagnostic model we constructed could diagnose PCa patients with high accuracy. Subsequently, based on the mRNAs in module 2, we constructed a prognostic model for 7-mRNAs (MYH11, ACTG2, DDR2, CDC42EP3, MARCKSL1, LMOD1, and MYLK) using multivariate Cox regression analysis. The prognostic model could predict the disease free survival of PCa patients with moderate to high accuracy (area under the curve (AUC) =0.761). In addition, Gene Set EnrichmentAnalysis (GSEA) and immune analysis indicated that the prognosis of patients in the risk group might be related to immune cell infiltration.

CONCLUSIONS

Our findings may provide new methods and insights for identifying disease-related biomarkers by integrating DNA methylation and gene expression data.

The role of circular RNA during the urological cancer metastasis: exploring regulatory mechanisms and potential therapeutic targets

Metastasis is a major contributor to treatment failure and death in urological cancers, representing an important biomedical challenge at present. Metastases form as a result of cancer cells leaving the primary site, entering the vasculature and lymphatic vessels, and colonizing clones elsewhere in the body. However, the specific regulatory mechanisms of action underlying the metastatic process of urological cancers remain incompletely elucidated. With the deepening of research, circular RNAs (circRNAs) have been found to not only play a significant role in tumor progression and prognosis but also show aberrant expression in various tumor metastases, consequently impacting tumor metastasis through multiple pathways. Therefore, circRNAs are emerging as potential tumor markers and treatment targets. This review summarizes the research progress on elucidating how circRNAs regulate the urological cancer invasion-metastasis cascade response and related processes, as well as their role in immune microenvironment remodeling and circRNA vaccines. This body of work highlights circRNA regulation as an emerging therapeutic target for urological cancers, which should motivate further specific research in this regard.

Single-cell RNA combined with bulk RNA analysis to explore oxidative stress and energy metabolism factors and found a new prostate cancer oncogene MXRA8

BACKGROUND

Prostate cancer is the most common malignancy among men worldwide, and its diagnosis and treatment are challenging due to its heterogeneity.

METHODS

Integrating single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq data, we identified two molecular subtypes of prostate cancer based on dysregulated genes involved in oxidative stress and energy metabolism. We constructed a risk score model (OMR) using common differentially expressed genes, which effectively evaluated prostate cancer prognosis.

RESULTS

Our analysis demonstrated a significant correlation between the risk score model and various factors, including tumor immune microenvironment, genomic variations, chemotherapy resistance, and immune response. Notably, patients with low-risk scores exhibited increased sensitivity to chemotherapy and immunotherapy compared to those with high-risk scores, indicating the model's potential to predict patient response to treatment. Additionally, our investigation of MXRA8 in prostate cancer showed significant upregulation of this gene in the disease as confirmed by PCR and immunohistochemistry. Functional assays including CCK-8, transwell, plate cloning, and ROS generation assay demonstrated that depletion of MXRA8 reduced the proliferative, invasive, migratory capabilities of PC-3 cells, as well as their ROS generation capacity.

CONCLUSIONS

Our study highlights the potential of oxidative stress and energy metabolism-related genes as prognostic markers and therapeutic targets in prostate cancer. The integration of scRNA-seq and bulk RNA-seq data enables a better understanding of prostate cancer heterogeneity and promotes personalized treatment development. Additionally, we identified a novel oncogene MXRA8 in prostate cancer.

Rho GTPase-activating protein 1 promotes hepatocellular carcinoma progression via modulation by CircPIP5K1A/MiR-101-3p

AIM

There has been an increased focus on regulating cell function with Rho family GTPases, including proliferation, migration/invasion, polarity, and adhesion. Due to the challenges involved in targeting Rho family GTPases directly, it may be more effective to target their regulators, such as Rho GTPase-activating protein 1 (ARHGAP1). This present research was performed to define the clinical significance of ARHGAP1 expression, as well as its regulatory mechanisms in hepatocellular carcinoma.

METHODS

ARHGAP1 and miR-101-3p expression of liver cancer patients, and their relevance with clinicopathological characteristics and prognosis were analyzed by the Cancer Genome Atlas sequencing data, and verified using samples of hepatocellular carcinoma patients. The interactions between miR-101-3p and ARHGAP1 or circPIP5K1A were validated by bioinformatic analyses, as well as confirmed by quantitative reverse transcription polymerase chain reaction, western blotting, and dual-luciferase reporter analysis. Plate clonality assays, cell adhesion and migration experiments, and proliferation experiments were used for assessing the participation of the circPIP5K1A/miR-101-3p/ARHGAP1 pathway in cell proliferation and motility.

RESULTS

Elevated ARHGAP1 and reduced miR-101-3p expression are related to poorer survival. MiR-101-3p targets ARHGAP1 to suppress hepatocellular carcinoma cell colony formation and invasion, whereas miR-101-3p inhibitor reverses liver cancer proliferation and metastasis suppression caused by ARHGAP1 knockdown. In addition, circPIP5K1A, which is mainly distributed in the cytosol, showed carcinogenic effects by sponging miR-101-3p, thus regulating ARHGAP1 expression.

CONCLUSIONS

ARHGAP1 serves as an oncogenic gene in liver cancer, and the expression thereof is regulated by circPIP5K1A through sponging miR-101-3p.

circSPECC1 Promotes Proliferation and Migration of LNCaP Prostate Cancer Cells by Affecting Their Epithelial-Mesenchymal Transition

Objective. To determine the effects of circSPECC1 (hsa_circ_0000745) on the proliferation and migration of LNCaP prostate cancer cells and to explore the potential molecular mechanism. Methods. Stable circSPECC1 shRNA-expressing and circSPECC1-overexpressing LNCaP cell lines were constructed, and relative gene expression levels were determined by RT-PCR. MTT and clonogenic assays were used to assess proliferative ability while a scratch test was used to analyze cell migration. Western blotting was used to determine protein expression levels. The effects of circSPECC1 on the proliferation of LNCaP prostate cancer cells were observed in vivo. Results. circSPECC1 was found to be derived from the SPECC1 (sperm antigen with calponin homology and coiled-coil domains 1) parent gene and to form a loop. Overexpression of circSPECC1 promoted the proliferation and migration of the LNCaP cells, whereas decreased expression of circSPECC1 inhibited these properties. Overexpression of circSPECC1 promoted the expression of MMP-2, MMP-9, VEGF, vimentin, and N-cad but downregulated the expression of E-cad. Decreased expression of circSPECC1 inhibited the expression of MMP-2, MMP-9, VEGF, vimentin, and N-cad but increased the expression of E-cad. Conclusion. circSPECC1 promotes cell proliferation and migration by affecting the epithelial-mesenchymal transition of LNCaP prostate cancer cells.

Circular RNAs: New layer of complexity evading breast cancer heterogeneity

Advances in high-throughput sequencing techniques and bioinformatic analysis have refuted the "junk" RNA hypothesis that was claimed against non-coding RNAs (ncRNAs). Circular RNAs (circRNAs); a class of single-stranded covalently closed loop RNA molecules have recently emerged as stable epigenetic regulators. Although the exact regulatory role of circRNAs is still to be clarified, it has been proven that circRNAs could exert their functions by interacting with other ncRNAs or proteins in their own physiologically authentic environment, regulating multiple cellular signaling pathways and other classes of ncRNAs. CircRNAs have also been reported to exhibit a tissue-specific expression and have been associated with the malignant transformation process of several hematological and solid malignancies. Along this line of reasoning, this review aims to highlight the importance of circRNAs in Breast Cancer (BC), which is ranked as the most prevalent malignancy among females. Notwithstanding the substantial efforts to develop a suitable anticancer therapeutic regimen against the heterogenous BC, inter- and intra-tumoral heterogeneity have resulted in an arduous challenge for drug development research, which in turn necessitates the investigation of other markers to be therapeutically targeted. Herein, the potential of circRNAs as possible diagnostic and prognostic biomarkers have been highlighted together with their possible application as novel therapeutic targets.

Bacterial lipopolysaccharide-related genes are involved in the invasion and recurrence of prostate cancer and are related to immune escape based on bioinformatics analysis

Background

The composition of the tumor microbial microenvironment participates in the whole process of tumor disease. However, due to the limitations of the current technical level, the depth and breadth of the impact of microorganisms on tumors have not been fully recognized, especially in prostate cancer (PCa). Therefore, the purpose of this study is to explore the role and mechanism of the prostate microbiome in PCa based on bacterial lipopolysaccharide (LPS)-related genes by means of bioinformatics.

Methods

The Comparative Toxicogenomics Database (CTD) was used to find bacterial LPS- related genes. PCa expression profile data and clinical data were acquired from TCGA, GTEx, and GEO. The differentially expressed LPS-related hub genes (LRHG) were obtained by Venn diagram, and gene set enrichment analysis (GSEA) was used to investigate the putative molecular mechanism of LRHG. The immune infiltration score of malignancies was investigated using single-sample gene set enrichment analysis (ssGSEA). Using univariate and multivariate Cox regression analysis, a prognostic risk score model and nomogram were developed.

Results

6 LRHG were screened. LRHG were involved in functional phenotypes such as tumor invasion, fat metabolism, sex hormone response, DNA repair, apoptosis, and immunoregulation. And it can regulate the immune microenvironment in the tumor by influencing the antigen presentation of immune cells in the tumor. And a prognostic risk score and the nomogram, which were based on LRHG, showed that the low-risk score has a protective effect on patients.

Conclusion

Microorganisms in the PCa microenvironment may use complex mechanism and networks to regulate the occurrence and development of PCa. Bacterial lipopolysaccharide-related genes can help build a reliable prognostic model and predict progression-free survival in patients with prostate cancer.

Circular RNA MYLK as a prognostic biomarker in patients with cancers: A systematic review and meta‐analysis

Background

Aims

Methods

Results

Conclusions

Discovering Gene Signature Shared by Prostate Cancer and Neurodegenerative Diseases Based on the Bioinformatics Approach

Background

Prostate cancer (PCa) is one of the highest frequent malignant tumors with very complicated pathogenesis. Genes of neurodegenerative diseases can influence tumor progression. But its role in the progression of PCa remains unclear. The purpose of the present academic work was to identify significant genes with poor outcome and their underlying mechanism.

Methods

The GSE70768, GSE88808, and GSE134051 datasets were downloaded to screen the differentially expressed genes (DEGs). The DEG screening criteria were as follows: P < 0.05 and differential fold change |logFC| ≥ 1. The common DEGs (co-DEGs) of the three datasets were obtained by the Robust Rank Aggregation (RRA) method. Gene Ontology (GO) function annotation and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis were performed using R software. Protein-protein interaction (PPI) network analysis was performed for co-DEGs using STRING to screen critical genes. Differential expression and prognosis of key genes were analyzed by the online tool Gene Expression Profiling Interactive Analysis 2 (GEPIA2). The intersection gene between key genes and neurodegenerative genes was identified by constructing a Venn diagram.

Results

A total of 263 co-DEGs were identified from the three datasets. GO analysis showed that co-DEGs were mainly involved in muscle contraction and blood circulation regulation. The top ten key genes were ACTG2, APOE, F5, CALD1, MYH11, MYL9, MYLK, TPM1, TPM2, and CALM1. GEPIA2 analysis showed that APOE, MYH11, and MYLK differ dramatically between tumor and normal tissues. These key genes are related to disease-free survival (DFS) in PCa. APOE was the intersection gene between key genes and Alzheimer-related genes.

Conclusion

The neurodegenerative gene APOE may be a potential prognostic and diagnostic biomarker for PCa.

Investigating the molecular mechanisms of Tamoxifen on the EMT pathway among patients with breast cancer

Tamoxifen is one of the most used drugs for breast cancer. This study aimed to investigate the effect of the Tamoxifen mechanism on the epithelial-mesenchymal transition (EMT) pathway among breast cancer patients due to its resistance to breast cancer cells. We selected the appropriate datasets from the GEO database using continuous and integrated bioinformatics analysis. We examined the signaling pathways, gene ontology, and protein association of genes after classifying the gene expression profile. Finally, we confirmed the candidate genes using the GEPIA database. Two groups were defined for gene expression profiles. The first group in which the expression profile of genes increased after Tamoxifen was evaluated using the expression profile of genes that decreased in the EMT pathway. The second group was the opposite of the first group. 253 genes in the first group and 302 genes in the second group were shared. The genes in the first group were involved in various pathways of cell death, focal adhesion, and cellular aging. The second group was more involved in different phases of the cell cycle. Finally, MYLK, SOCS3, and STAT5B proteins from the first group and BIRC5, PLK1, and RAPGAP1 proteins from the second group were selected as candidate proteins in connection with the effect of Tamoxifen on the EMT pathway. We evaluated Tamoxifen's effect on the EMT pathway more accurately. However, for a closer look at Tamoxifen, more studies need to be done on target genes and proteins to clarify their role.

Circular RNA CCDC66 Regulates Osteoarthritis Progression by Targeting miR-3622b-5p

OBJECTIVE

CircCCDC66 is involved in cancer progression, but its role in osteoarthritis (OA) remains unknown. This study was carried out to explore the biological role of circCCDC66 in OA and its underlying mechanism.

METHODS

The expression levels of miR-3622b-5p and circCCDC66 in OA cartilage tissues were detected by qRT-PCR. Cell Counting Kit-8 (CCK8) and flow cytometry were used to detect the chondrocyte viability and apoptosis. The expression of chondrocyte inflammatory factors (IL-6 and TNF-α) was measured by ELISA. The target genes of circCCDC66 and miR-3622b-5p were analyzed by bioinformatics analysis and luciferase reporter gene assay. The relationship between circCCDC66 and miR-3622b-5p was analyzed by bioinformatics analysis and luciferase reporter gene assay.

RESULTS

It was found that circCCDC66 expression in OA cartilage tissues was upregulated. CircCCDC66 overexpression inhibited proliferation and promoted apoptosis of chondrocytes and increased IL-6 and TNF-α levels in chondrocytes. miR-3622b-5p was predicted to be a downstream target gene of circCCDC66, and circCCDC66 overexpression inhibited miR-3622b-5p expression in chondrocytes. Moreover, miR-3622b-5p expression was downregulated in OA cartilage tissues. miR-3622b-5p overexpression increased chondrocyte proliferation, inhibited chondrocyte apoptosis, and enhanced the expression of IL-6 and TNF-α in chondrocytes. In addition, circCCDC66 overexpression enhanced SIRT3 expression in chondrocytes, while miR-3622b-5p overexpression inhibited SIRT3 expression in chondrocytes.

CONCLUSION

CircCCDC66 promoted OA chondrocyte apoptosis by regulating the miR-3622b-5p/SIRT3 axis. CircCCDC66 may be a new therapeutic target of OA.

Prediction of potential prognostic biomarkers in metastatic prostate cancer based on a circular RNA-mediated competing endogenous RNA regulatory network

Recently, studies on competing endogenous RNA (ceRNA) networks have become prevalent, and circular RNAs (circRNAs) have crucial implications for the development and progression of carcinoma. However, studies relevant to metastatic prostate cancer (mPCa) are scant. This study aims to discover potential ceRNAs that may be related to the prognosis of mPCa. RNA-Seq data were obtained from the MiOncoCirc database and Gene Expression Omnibus (GEO). Differential expression patterns of RNAs were examined using R packages. Circular RNA Interactome, miRTarBase, miRDB and TargetScan were applied to predict the corresponding relation between circRNAs, miRNAs and mRNAs. The Gene Ontology (GO) annotations were performed to present related GO terms, and Gene Set Enrichment Analysis (GSEA) tools were applied for pathway annotations. Moreover, survival analysis was conducted for the hub genes. We found 820 circRNAs, 81 miRNAs and 179 mRNAs that were distinguishingly expressed between primary prostate cancer (PCa) and mPCa samples. A ceRNA network including 45 circRNAs, 24 miRNAs and 56 mRNAs was constructed. In addition, the protein–protein interaction (PPI) network was built, and 10 hub genes were selected by using the CytoHubba application. Among the 10 hub genes, survival analysis showed that ITGA1, LMOD1, MYH11, MYLK, SORBS1 and TGFBR3 were significantly connected with disease-free survival (DFS). The circRNA-mediated ceRNA network provides potential prognostic biomarkers for metastatic prostate cancer.

Circular RNAs in prostate cancer: Biogenesis,biological functions, and clinical significance

Circular RNAs (circRNAs) are covalently closed RNA molecules that play important regulatory roles in various tumors. Prostate cancer (PCa) is one of the most common malignant tumors in the world, with high morbidity and mortality. In recent years, more and more circRNAs have been found to be abnormally expressed and involved in the occurrence and development of PCa, including cell proliferation, apoptosis, invasion, migration, metastasis, chemotherapy resistance, and radiotherapy resistance. Most of the circRNAs regulate biological behaviors of cancer through a competitive endogenous RNA (ceRNA) regulatory mechanism, and some can exert their functions by binding to proteins. circRNAs are also associated with many clinicopathological features of PCa, including tumor grade, lymph node metastasis, and distant metastasis. In addition, circRNAs are potential diagnostic and prognostic biomarkers for PCa. Considering their critical regulatory roles in the progression of PCa, circRNAs would be the potential therapeutic targets. In this paper, the current research status of circRNAs in PCa is briefly reviewed.

The Role and Clinical Potentials of Circular RNAs in Prostate Cancer

Globally, prostate cancer (PCa) is the second most commonly diagnosed cancer in men globally. Early diagnosis may help in promoting survival in the affected patients. Circular RNAs (circRNAs) are a novel class of non-coding RNAs (ncRNAs) which have been found to show extensive dysregulation in a handful of human diseases including cancers. Progressions in RNA identification techniques have provided a vast number of circRNAs exhibiting either up-regulation or down-regulation in PCa tissues compared to normal adjacent tissues. The mechanism of action is not clear for most of dysregulated circRNAs. Among them, function of a number of newly identified dysregulated circRNAs have been assessed in PCa cells. Increase in cell proliferation, migration, invasion, and metastasis have been reported for up-regulated circRNAs which suggest their role as oncogenes. On the other hand, down-regulated circRNAs have shown tumor suppressing actions in experimental studies. Furthermore, in a majority of studies, circRNAs have been found to sponge microRNAs (miRNAs), negatively regulating expression or activity of the downstream miRNAs. Additionally, they have been identified in interaction with regulatory proteins. This axis consequently regulates a signaling pathway, a tumor suppressor, or an oncogene. Easy, quick, and reliable detection of circRNAs in human body fluids also suggests their potentials as biomarker candidates for diagnosis and prediction of prognosis in PCa patients. In this review, we have discussed the role and potentials of a number of dysregulated circRNAs in PCa.

Characteristics of circRNA and its approach as diagnostic tool in melanoma

One of the most common types of cancer in the world is skin cancer, which has been divided into two groups: non-melanoma and melanoma skin cancer. Different external and internal agents are considered as risk factors for melanoma skin cancer pathogenesis but the exact mechanisms are not yet confirmed. Genetic and epigenetic changes, UV exposure, arsenic compounds, and chemical substances are contributory factors to the development of melanoma. A correlation has emerged between new therapies and the discovery of a basic molecular pattern for skin cancer patients. Circular RNAs (circRNAs) are described as a unique group of extensively expressed endogenous regulatory RNAs with closed-loop structure bonds connecting the 5' and 3' ends, which are commonly expressed in mammalian cells. In this review, we describe the biogenesis of circular RNAs and its function in cancerous conditions focusing on the crosstalk between different circRNAs and melanoma. Increasing evidence suggests that circRNAs appears to be relative to the origin and development of skin-related diseases like malignant melanoma. Different circular RNAs like hsa_circ_0025039, hsa_circRNA006612, circRNA005537, and circANRIL, by targeting different cellular and molecular targets (e.g., CDK4, DAB2IP, ZEB1, miR-889, and let-7 c-3p), can participate in melanoma cancer progression.

The Circular RNA circXPO1 Promotes Tumor Growth via Sponging MicroRNA-23a in Prostate Carcinoma

It has been shown that circular RNA XPO1 (circXPO1) is involved in cancer (e.g., lung adenocarcinoma and osteosarcoma) progression by sponging microRNAs. Nevertheless, the role of circXPO1 and its interaction with microRNAs in prostate cancer remains unknown. In this study, the results of quantitative real-time PCR showed that circXPO1 levels were dramatically increased in human prostate cancer tissue and cell lines compared with those in normal tissue and cell line. Furthermore, cell proliferation, colony formation, and cell invasion assays showed that circXPO1 promoted the malignant behavior of pancreatic cells in vitro. Mechanistically, bioinformatics prediction, a dual-luciferase reporter assay, and pull-down assay suggested that circXPO1 physically targets miR-23a and negatively regulates its expression in pancreatic cancer cells. miR-23a mimics and inhibitors effectively reversed the effects of circXPO1 on the malignant behavior of prostate cancer cells in vitro. Consistent results were observed in the xenograft tumor model. In conclusion, circXPO1 promotes prostate cancer progression via targeting miR-23a, thus suggesting the circXPO1/miR-23a axis can be used as a potential therapeutic target for prostate cancer treatment.

The Emerging Role of Circular RNAs in Prostate Cancer: A Systematic Review

Prostate cancer is one of the most common malignant tumors that threaten the health of men. It is urgent to explore new molecular targets and develop new drugs for the treatment of prostate cancer. Circular RNAs (circRNAs) are aberrantly expressed in various malignant tumors. The dysregulated circRNAs are involved in the metastasis, tumor growth, drug resistance, and immunosuppression of malignant tumors. The present review systematically summarized publications concerning the biological implications of circRNAs in prostate cancer. The PubMed and Web of Science databases were used to retrieve publications concerning circRNAs and prostate cancer until June 16, 2021. The following keywords were used in the literature search: (circRNA OR circular RNA) AND prostate cancer. 73 publications were enrolled in the present systematic review to summarize the role of circRNAs in prostate cancer. The dysregulated and functional circRNAs were involved in the cell cycle, proliferation, migration, invasion, metastasis, drug resistance and radiosensitivity of prostate cancer. In addition, circRNAs could function through EVs and serve as prognostic and diagnostic biomarkers. Certain circRNAs were correlated with clinicopathological features of prostate cancer. A comprehensive review of the molecular mechanism of the tumorigenesis and progression of prostate cancer may contribute to the development of new therapies of prostate cancer in the future.

Circular RNA-DPP4 serves an oncogenic role in prostate cancer progression through regulating miR-195/cyclin D1 axis

BACKGROUND

Recently, more and more studies have highlighted the critical regulatory roles of circular RNAs (circRNAs), a class of non-coding RNAs, in the progression of many human cancers, including prostate cancer (PCa). circRNA microarray analysis was performed to identify circRNAs that are differentially expressed in PCa tissues.

METHODS

104 pairs of PCa tissues and matched adjacent normal prostate tissues (at least 2 cm distal to the tumor margin) were obtained. circRNA microarray analysis was performed on four pairs of PCa tissues and matched adjacent normal prostate tissues to investigate the potential involvement of circRNAs in PCa. Flow cytometric analysis was performed to investigate whether the effect of circDPP4 on PCa cell proliferation was associated with the alteration in cell cycle progression. The role of circDPP4 in PCa tumor growth was further explored in vivo.

RESULTS

We found that circDPP4 was overexpressed in PCa tissues and cell lines, and its expression was closely associated with Gleason score and clinical stage of PCa patients. In vitro loss- and gain-of-function experiments demonstrated that circDPP4 knockdown inhibited, whereas circDPP4 overexpression promoted the proliferation, migration, invasion and cell cycle progression of PCa cells. Knockdown of circDPP4 also suppressed PCa tumor growth in vivo. We further found that circDPP4 functioned as a competing endogenous RNA (ceRNA) for miR-195 in PCa cells, and miR-195 negatively regulated the expression of oncogenic cyclin D1. Rescue experiments suggested that restoration of miR-195 blocked the oncogenic role of circDPP4 in PCa cells.

CONCLUSIONS

Taken together, our findings revealed a novel regulatory mechanism between circDPP4 and miR-195/cyclin D1 axis, and offered novel strategies for the treatment of PCa.

hsa_circ_0062019 promotes the proliferation, migration, and invasion of prostate cancer cells via the miR-195-5p/HMGA2 axis

Circular RNA (circRNA) is a new class of non-coding RNA. It was reported that circRNA involves in the metastasis of cancer. The aim of this study is to explore the role and mechanism of circRNA hsa_circ_0062019 in the development of prostate cancer (PCa). Our results showed that hsa_circ_0062019 was highly expressed in PCa cell lines. Cell Counting Kit-8 assay revealed that upregulation of hsa_circ_0062019 boosted PCa cell proliferation, and silencing of hsa_circ_0062019 inhibited cell proliferation. Meanwhile, transwell assay proved that upregulation of hsa_circ_0062019 facilitated PCa cell invasion and migration, while downregulation of hsa_circ_0062019 inhibited these malignant phenotypes. Furthermore, luciferase reporter assay proved the binding of hsa_circ_0062019 with miR-195-5p and the binding between miR-195-5p and high mobility group AT-hook 2 (HMGA2), suggesting that hsa_circ_0062019 promoted the expression of HMGA2 by sponging miR-195-5p. In addition, our results revealed that the hsa_circ_0062019-induced PCa cell malignant phenotypes were notably reversed by the downregulation of HMGA2. Overall, our study demonstrated that hsa_circ_0062019 promoted PCa cell proliferation, migration, and invasion via upregulation of HMGA2 expression by sponging miR-195-5p. Our study proved a novel molecular mechanism of PCa development and provided a potential target for the treatment of PCa.

CircMYLK promotes the growth, migration, invasion, and survival of bladder cancer cells by upregulating CCND3 level via competitively binding to miR-34a

Bladder cancer is one of the most common types of urothelial carcinoma with a rising incidence rate worldwide. Circular RNAs (circRNAs) are involved in the development of numerous cancers, including bladder cancer. We aimed to uncover the role and associated mechanism of circMYLK in bladder cancer. The expression levels of circMYLK, miRNA-34a (miR-34a) and Cyclin D3 (CCND3) mRNA were investigated using real-time quantitative polymerase chain reaction. The protein level of CCND3 was investigated using western blot. In functional assays, flow cytometry assays were utilized for cell cycle analysis and cell apoptosis analysis. Transwell assays were used for cell migration and invasion analysis. Caspase-3 activity was examined to monitor cell apoptosis. The putative relationship between miR-34a and circMYLK or CCND3 was validated by dual-luciferase reporter assay and RNA immunoprecipitation assay. CircMYLK was highly expressed in bladder cancer tissues and cells. CircMYLK downregulation inhibited bladder cancer cell migration and invasion, and promoted cancer cell apoptosis and cell cycle arrest. MiR-34a, a target of circMYLK, was downregulated in bladder cancer tissues and cells. MiR-34a inhibition reversed the effects of circMYLK downregulation and then recovered bladder cell malignant behaviors. Further analysis showed that CCND3 was a downstream target of miR-34a, and CCND3 was upregulated in bladder cancer tissues and cells. MiR-34a overexpression blocked bladder cancer cell migration and invasion, and induced cell apoptosis and cycle arrest, while these effects were abolished by CCND3 overexpression. CircMYLK contributed to the malignant development of bladder cancer cells partly through the miR-34a/CCND3 regulatory network, showing the significance of circMYLK in bladder cancer pathogenesis.

Circ_0001686 Promotes Prostate Cancer Progression by Up-Regulating SMAD3/TGFBR2 via miR-411-5p

Purpose

As the mechanism of interaction between circular RNAs (circRNAs) and microRNAs (miRNAs) in regulating the development of prostate cancer (PCa) is not clear, this study focuses on investigating these effects.

Materials and Methods

Sample tissues were collected from the PCa of patients, and microarray analysis of human circRNAs was conducted. The expression of circ_0001686, hsa_miR-411-5p (miR-411-5p) were also detected by qRT-PCR. Circ_0001686 and miR-411-5p mimics were transfected into the PCa cell lines (CWR22RV1and LNCaP) and MTT, colony formation, Transwell, and scratch wound assays were used to analyze the biological behaviors of PCa cells. Si-circ_0001686 and ASO-miR-411-5p were used as negative controls, and dual-luciferase reporter assays were performed to verify the interactions among circ_0001686, miR-411-5p, and SMAD3/TGFBR2. The levels of SMAD3 and TGFBR2 in different treated PCa cells were measured by western blot, and in vivo experiments in a nude mouse model were carried out to strengthen the in vitro findings of miR-411-5p.

Results

The expression of circ_0001686 was up-regulated, while the expression of miR-411-5p was down-regulated in PCa cells. Moreover, circ_0001686 promoted cell proliferation, migration, and invasion. Molecular mechanism exploration revealed that circ_0001686 could reduce miR-411-5p, affecting the downstream target genes of SMAD3 and TGFBR2. In vitro and in vivo studies verified that miR-411-5p inhibits PCa progression.

Conclusions

Circ_0001686 can reduce miR-411-5p to increase the expression of SMAD3/TGFBR2, which consequently promotes the proliferation, invasion, and migration of PCa cells.

CircRNA-Mediated Regulation of Angiogenesis: A New Chapter in Cancer Biology

Angiogenesis is necessary for carcinoma progression and is regulated by a variety of pro- and anti-angiogenesis factors. CircRNAs are RNA molecules that do not have a 5'-cap or a 3'-polyA tail and are involved in a variety of biological functions. While circRNA-mediated regulation of tumor angiogenesis has received much attention, the detailed biological regulatory mechanism remains unclear. In this review, we investigated circRNAs in tumor angiogenesis from multiple perspectives, including its upstream and downstream factors. We believe that circRNAs have natural advantages and great potential for the diagnosis and treatment of tumors, which deserves further exploration.

MYLK and PTGS1 Genetic Variations Associated with Osteoporosis and Benign Breast Tumors in Korean Women

Osteoporosis, characterized by reduced bone mass and increased bone fragility, is a disease prevalent in women. Likewise, breast cancer is a multifactorial disease and considered the major cause of mortality in premenopausal and postmenopausal women worldwide. Our data demonstrated the association of the MYLK gene and PTGS1 gene variants with osteoporosis and benign breast tumor risk and the impact of ovariectomy on osteoporosis in Korean women. We performed a genome-wide association study (GWAS) of women with osteoporosis and benign breast tumors. There were 60 single nucleotide polymorphisms (SNPs) and 12 SNPs in the MYLK and PTGS1 genes, associated with benign breast tumors and osteoporosis. Our study showed that women with homozygous MYLK rs12163585 major alleles had an increased risk of osteoporosis following ovariectomy compared to those with minor alleles. Women carrying the minor PTGS1 rs1213265 allele and not treated via ovariectomy carried a higher risk of osteoporosis than those who underwent ovariectomy with a homozygous genotype at the major alleles. Our results suggest that both the MYLK and PTGS1 genes are genetic factors associated with the phenotypes, and these associations appear to be modulated by ovariectomy.

Non-Coding RNAs Set a New Phenotypic Frontier in Prostate Cancer Metastasis and Resistance

Prostate cancer (PCa) mortality remains a significant public health problem, as advanced disease has poor survivability due to the development of resistance in response to both standard and novel therapeutic interventions. Therapeutic resistance is a multifaceted problem involving the interplay of a number of biological mechanisms including genetic, signaling, and phenotypic alterations, compounded by the contributions of a tumor microenvironment that supports tumor growth, invasiveness, and metastasis. The androgen receptor (AR) is a primary regulator of prostate cell growth, response and maintenance, and the target of most standard PCa therapies designed to inhibit AR from interacting with androgens, its native ligands. As such, AR remains the main driver of therapeutic response in patients with metastatic castration-resistant prostate cancer (mCRPC). While androgen deprivation therapy (ADT), in combination with microtubule-targeting taxane chemotherapy, offers survival benefits in patients with mCRPC, therapeutic resistance invariably develops, leading to lethal disease. Understanding the mechanisms underlying resistance is critical to improving therapeutic outcomes and also to the development of biomarker signatures of predictive value. The interconversions between epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) navigate the prostate tumor therapeutic response, and provide a novel targeting platform in overcoming therapeutic resistance. Both microRNA (miRNA)- and long non-coding RNA (lncRNA)-mediated mechanisms have been associated with epigenetic changes in prostate cancer. This review discusses the current evidence-based knowledge of the role of the phenotypic transitions and novel molecular determinants (non-coding RNAs) as contributors to the emergence of therapeutic resistance and metastasis and their integrated predictive value in prostate cancer progression to advanced disease.

Advancement and properties of circular RNAs in prostate cancer: An emerging and compelling frontier for discovering

Prostate cancer (PC) is the most common carcinoma among men worldwide which results in 26% of leading causes of cancer-related death. However, the ideal and effective molecular marker remains elusive. CircRNA, initially observed in plant-infected viruses and Sendai virus in 1979, is generated from pre-mRNA back-splicing and comes in to play by adequate expression. The differential expression in prostate tissues compared with the control reveals the promising capacity in modulating processes including carcinogenesis and metastasis. However, the biological mechanisms of regulatory network in PC needs to systemically concluded. In this review, we enlightened the comprehensive studies on the definite mechanisms of circRNAs affecting tumor progression and metastasis. What's more, we validated the potential clinical application of circRNAs serving as diagnostic and prognostic biomarker. The discussion and analysis in circRNAs will broaden our knowledge of the pathogenesis of PC and further optimize the current therapies against different condition.

Non-coding RNAs and potential therapeutic targeting in cancer

Recent advances have begun to clarify the physiological and pathological roles of non-coding RNAs (ncRNAs) in various diseases, including cancer. Among these, microRNAs (miRNAs) have been the most studied and have emerged as key players that are involved in the regulation of important growth regulatory pathways in cancer pathogenesis. The ability of a single ncRNA to modulate the expression of multiple downstream gene targets and associated pathways, have provided a rationale to pursue them for therapeutic drug development in cancer. In this context, early data from pre-clinical studies have demonstrated that synthetic miRNA-based therapeutic molecules, along with various protective coating approaches, has allowed for their efficient delivery and anti-tumor activity. In fact, some of the miRNA-based cancer therapeutic strategies have shown promising results even in early-phase human clinical trials. While the enthusiasm for ncRNA-based cancer therapeutics continue to evolve, the field is still in the midst of unraveling a more precise understanding of the molecular mechanisms and specific downstream therapeutic targets of other lesser studied ncRNAs such as the long-non-coding RNAs, transfer RNAs, circular RNAs, small nucleolar RNAs, and piwi-interacting RNAs. This review article provides the current state of knowledge and the evolving principles for ncRNA-based therapeutic approaches in cancer, and specifically highlights the importance of data to date and the approaches that are being developed to overcome the challenges associated with their delivery and mitigating the off-target effects in human cancers.

Silencing circSLC19A1 Inhibits Prostate Cancer Cell Proliferation, Migration and Invasion Through Regulating miR-326/MAPK1 Axis

Background

Emerging evidence indicates that circular RNAs (circRNAs), which form as covalently closed loops, play a regulatory role in various types of cancer, including prostate cancer (PCa). CircSLC19A1, one kind of circRNA, was subjected to the study and its role in PCa was explored.

Methods

Expressions of circSLC19A1, miR-326 and MAPK1 in PCa tissues and cells were assessed by qRT-PCR. CircSLC19A1 was identified by RNase R treatment. The binding relations between circSLC19A1 and miR-326 and between miR-326 and MAPK1 were predicted by RegRNA2.0 or Targetscan7.2 and further confirmed by dual-luciferase reporter assay. Pearson correlation analysis of the correlation among circSLC19A1, miR-326 and MAPK1 was performed. CCK-8, cell colony formation, wound healing and Transwell assays were used to assess PCa cell viability, proliferation, migration and invasion, respectively.

Results

CircSLC19A1 expression was up-regulated in PCa tissue and cell cytoplasm. Silencing circSLC19A1 inhibited PCa cell viability, proliferation, migration, invasion and miR-326 expression. MiR-326 inhibitor promoted the luciferase activities of circSLC19A1 and MAPK1, increased MAPK1 expression and facilitated PCa cell progression. MiR-326 expression was down-regulated in PCa tissue and there was a negative correlation between miR-326 and circSLC19A1 expressions. MAPK1 expression was up-regulated in PCa tissue. There was a negative correlation between MAPK1 and miR-326 expressions as well as a positive correlation between MAPK1 and circSLC19A1 expressions. Silencing MAPK1 promoted the viability, proliferation, migration, and invasion of PCa cells co-transfected with siRNA-circSLC19A1a and miR-326 inhibitor.

Conclusion

CircSLC19A1 silencing inhibited PCa cell proliferation, migration and invasion through regulating miR-326/MAPK1 axis.

Hsa_circ_0088233 Alleviates Proliferation, Migration, and Invasion of Prostate Cancer by Targeting hsa-miR-185-3p

Prostate cancer is the most common malignant tumor of the urinary system. The mechanisms of the initiation and progression of prostate cancer have not been fully elucidated. Increasing evidence suggests that circular RNAs (circRNAs) are involved in cancer pathogenesis. In this study, we aimed to identify differentially expressed circRNAs in prostate cancer tissues and explored the role of circRNAs in the pathogenesis of prostate cancer. By screening a circRNA microarray assay, we found that circ_0088233 was upregulated in prostate cancer tissues compared to adjacent normal tissues, and this upregulation can be verified in 46 pairs of prostate cancer and adjacent normal tissues examined using quantitative reverse transcription-PCR. The level of circ_0088233 correlated with the TNM stage. Knockdown of circ_0088233 reduced cell proliferation, migration, invasion, and induced G1 phase arrest and apoptosis. In addition, miR-185-3p was identified as the downstream target of circ_0088233 using luciferase reporter assays and a biotinylated circ_0088233 probe pull-down assay. The miR-185-3p level showed a negative correlation with the circ_0088233 level in prostate cancer tissues. Overexpression of circ_0088233 blocked the effects of miR-185-3p on cell proliferation, migration, invasion, cell cycle, and apoptosis. In conclusion, circ_0088233 may function as an oncogene and play an oncogenic role by sponging hsa-miR-185-3p. This study increases the understanding of circRNAs in the progression of prostate cancer. These results implicate circ_0088233 as a potential therapeutic target for prostate cancer.

Circular RNAs and Their Linear Transcripts as Diagnostic and Prognostic Tissue Biomarkers in Prostate Cancer after Prostatectomy in Combination with Clinicopathological Factors

As new biomarkers, circular RNAs (circRNAs) have been largely unexplored in prostate cancer (PCa). Using an integrative approach, we aimed to evaluate the potential of circRNAs and their linear transcripts (linRNAs) to act as (i) diagnostic biomarkers for differentiation between normal and tumor tissue and (ii) prognostic biomarkers for the prediction of biochemical recurrence (BCR) after radical prostatectomy. In a first step, eight circRNAs (circATXN10, circCRIM1, circCSNK1G3, circGUCY1A2, circLPP, circNEAT1, circRHOBTB3, and circSTIL) were identified as differentially expressed via a genome-wide circRNA-based microarray analysis of six PCa samples. Additional bioinformatics and literature data were applied for this selection process. In total, 115 malignant PCa and 79 adjacent normal tissue samples were examined using robust RT-qPCR assays specifically established for the circRNAs and their linear counterparts. Their diagnostic and prognostic potential was evaluated using receiver operating characteristic curves, Cox regressions, decision curve analyses, and C-statistic calculations of prognostic indices. The combination of circATXN10 and linSTIL showed a high discriminative ability between malignant and adjacent normal tissue PCa. The combination of linGUCY1A2, linNEAT1, and linSTIL proved to be the best predictive RNA-signature for BCR. The combination of this RNA signature with five established reference models based on only clinicopathological factors resulted in an improved predictive accuracy for BCR in these models. This is an encouraging study for PCa to evaluate circRNAs and their linRNAs in an integrative approach, and the results showed their clinical potential in combination with standard clinicopathological variables.

Circular RNA MYLK Promotes Hepatocellular Carcinoma Progression Through the miR29a/KMT5C Signaling Pathway

Purpose

This study aimed to investigate the functions of the circular RNA circMYLK (hsa_circ_0002768) in the development of hepatocellular carcinoma (HCC) and to identify the underlying mechanisms of the circMYLK/miR29a/KMT5C axis.

Materials and Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to explore the expressions of circMYLK, miR-29a and KMT5C in HCC tissues and cells. A potential miRNA (miR-29a) regulated by circMYLK was also explored, and the target relationship between miR-29a and KMT5C was confirmed. FISH, qRT-PCR, Western blotting, and dual-luciferase reporter assays were used to examine the circMYLK/miR29a/KMT5C signaling pathways involved in HCC development. Additionally, HCC cells were implanted into nude mice subcutaneously to test the role of circMYLK in tumor growth.

Results

circMYLK was determined to be significantly upregulated in HCC tissues and cells. Suppression of circMYLK repressed HCC cell proliferation, migration, and invasion while increasing apoptosis. In addition, FISH, qRT-PCR, and Western blotting, as well as dual-luciferase reporter assays, revealed that circMYLK could bind to miR-29a. In rescue experiments, miR-29a had the potential to eliminate the inhibitory effect of circMYLK knockdown in HCC. Moreover, miR-29a was found to target the KMT5C gene, which was positively regulated by circMYLK. Finally, a nude mouse tumorigenicity assay showed that injection of circMYLK siRNA into nude mice drastically suppressed xenograft tumor formation in vivo.

Conclusion

Our current study demonstrated that circMYLK promotes HCC progression by acting as a competing endogenous RNA of miR-29a, which regulates the downstream oncogene KMT5C.

Circular RNA and its potential as prostate cancer biomarkers

Advancing knowledge of the transcriptome has revealed that circular RNAs (circRNAs) are widely expressed and evolutionarily conserved molecules that may serve relevant biological roles. More interesting is the accumulating evidence which demonstrates the implication of circRNAs in diseases, especially cancers. This revelation has helped to form the rationale for many studies exploring their utility as clinical biomarkers. CircRNAs are highly stable due to their unique structures, exhibit some tissue specificity, and are enriched in exosomes, which facilitate their detection in a range of body fluids. These properties make circRNAs ideal candidates for biomarker development in many diseases. This review will outline the discovery, biogenesis, and proposed functions of circRNAs.

Knockdown of Circ_CCNB2 Sensitizes Prostate Cancer to Radiation Through Repressing Autophagy by the miR-30b-5p/KIF18A Axis

Background: Circular RNAs (circRNAs) have recently emerged as crucial regulatory molecules in prostate cancer (PCa), but few researches focus on the effects of circRNAs on PCa radiosensitivity. The issue will be addressed in this study using circRNA Cyclin B2 (circ_CCNB2) as an object. Materials and Methods: All RNA and protein levels were severally examined using quantitative real-time polymerase chain reaction and Western blot. Colony formation assay and flow cytometry were implemented for detecting cell colony capacity and apoptotic cells, respectively. Cellular migration and invasion abilities were evaluated by transwell assay. The combination between potential target molecules was analyzed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The effect of circ_CCNB2 on PCa radiosensitivity in vivo was explored using xenograft models in mice. Results: Circ_CCNB2 was upregulated in irradiation-resistant PCa tissues and cells. Circ_CCNB2 knockdown had promoted effect on the radiosensitivity of irradiation-resistant PCa cells by inhibiting autophagy. Besides, circ_CCNB2 could directly sponge miR-30b-5p, and the promotion of circ_CCNB2 knockdown on PCa radiosensitivity was achieved by elevating miR-30b-5p. MiR-30b-5p enhanced the radiosensitivity of irradiation-resistant PCa cells through repressing the expression of its target kinesin family member 18A (KIF18A). Furthermore, circ_CCNB2 regulated the KIF18A level through targeting miR-30b-5p. Circ_CCNB2 downregulation facilitated PCa radiosensitivity in vivo through inhibiting autophagy by miR-30b-5p/KIF18A. Conclusions: In this study, knockdown of circ_CCNB2 was shown to promote PCa radiosensitivity through autophagy repression by miR-30b-5p/KIF18A axis, developing a molecular resistance mechanism of PCa radiotherapy and a feasible strategy to increase radiosensitivity.

Bioinformatic screening and identification of downregulated hub genes in adrenocortical carcinoma

The molecular mechanisms of adrenocortical carcinoma (ACC) carcinogenesis and progression remain unclear. In the present study, three microarray datasets from the Gene Expression Omnibus database were screened, which identified a total of 96 differentially expressed genes (DEGs). A protein-protein interaction network (PPI) was established for these DEGs and module analysis was performed using STRING and Cytoscape. A total of eight hub genes were identified from the most significant module; namely, calponin 1 (CNN1), myosin light chain kinase (MYLK), cysteine and glycine rich protein 1 (CSRP1), myosin heavy chain 11 (MYH11), fibulin extracellular matrix protein 2 (EFEMP2), fibulin 1 (FBLN1), microfibril associated protein 4 (MFAP4) and fibulin 5 (FBLN5). The biological functions of these hub genes were analyzed using the DAVID online tool. Changes in the expression of hub genes did not affect overall survival; however, downregulated EFEMP2 decreased disease-free survival. CSRP1 and MFAP4 expression levels were associated with adverse clinicopathological features. In conclusion, although all eight hub genes were downregulated in ACC, they appeared to have important functions in ACC carcinogenesis and progression. Identification of these genes complements the genetic expression profile of ACC and provides insight for the diagnosis, treatment and prognosis of ACC.

Circular RNA MYLK Promotes Glycolysis and Proliferation of Non-Small Cell Lung Cancer Cells by Sponging miR-195-5p and Increasing Glucose Transporter Member 3 Expression

Introduction

Circular RNAs (circRNAs) are deregulated in many types of human cancers, including non-small cell lung cancer (NSCLC). In this study, we aimed to explore the functional role of circMYLK in NSCLC.

Materials and Methods

The expression levels of circMYLK and miR-195-5p in NSCLC tissues and cell lines were detected by RT-qPCR analysis. MTT assay, colony formation assay and transwell assay were performed to investigate the effects of circMYLK and miR-195-5p on the malignant phenotypes of NSCLC cells. The glucose consumption and lactate production of NSCLC cells were detected using commercial kits. The direct binding relation between circMYLK and miR-195-5p in NSCLC was predicted by bioinformatics analysis and validated by dual-luciferase reporter assay.

Results

The results showed that circMYLK was significantly up-regulated in NSCLC tissues and cell lines, and its high expression was closely associated with deleterious clinicopathological characteristics and poor prognosis of NSCLC patients. Knockdown of circMYLK remarkably inhibited the malignant phenotypes of NSCLC cells, including proliferation, migration, invasion, glucose consumption and lactate production. Moreover, circMYLK was identified as a molecule sponge for miR-195-5p, and glucose transporter member 3 (GLUT3) was shown to be a target gene of miR-195-5p in NSCLC. Further rescue experiments revealed that the oncogenic effects of circMYLK on NSCLC cells could be largely abrogated by co-transfection with miR-195-5p mimic.

Conclusion

In summary, our study provides convincing evidence that circMYLK serves as a tumor promoter in NSCLC and can be used as a potential therapeutic target for NSCLC patients.

Circular RNA circ-ZEB1 acts as an oncogene in triple negative breast cancer via sponging miR-448

BACKGROUND

Circular RNAs (circRNAs) play an important role in tumor development. The miRNA sponge is a common role played by circRNAs in various tumors, including breast cancer.

OBJECTIVE

This study aimed to explore the role of circ-ZEB1 in the proliferation and apoptosis of triple negative breast cancer (TNBC) cells.

METHODS

The expressions of several circRNAs which were predicted to be bound with miR-448 were detected in 30 clinical TNBC tumor tissues and paired paracancer tissues. The cell counting kit-8 assay was performed to detect the TNBC cell proliferation. The TNBC cell apoptosis was detected using the TUNEL assay. The binding between circ-ZEB1 and miR-448, as well as between miR-448 and eukaryotic elongation factor 2 kinase (eEF2 K), was detected using the RNA pull-down assay and/or the luciferase reporter assay. The effect of circ-ZEB1 knockdown on TNBC tumor growth was detected using the mouse xenograft model.

RESULTS

Compared with normal tissues and breast epithelial cells, the expression of circ-ZEB1 was markedly higher in TNBC tumor tissues and tumor cell lines. The small hairpin RNA-mediated circ-ZEB1 knockdown inhibited TNBC cell proliferation and induced cell apoptosis. The RNA pull-down assay and the luciferase reporter assay confirmed the binding between circ-ZEB1 and miR-448, as well as between miR-448 and eEF2 K. The knockdown of circ-ZEB1 was proven to inhibit TNBC cell proliferation and tumor growth via releasing miR-448, and subsequently reducing the expression of the miR-448 target, eEF2 K.

CONCLUSION

In conclusion, our findings identified a new functional circ-ZEB1 in TNBC tumorigenesis, and revealed the important regulatory role of circ-ZEB1 via sponging miR-448, providing a novel insight for TNBC pathogenesis.

Circular RNA MYLK promotes tumour growth and metastasis via modulating miR-513a-5p/VEGFC signalling in renal cell carcinoma

Growing evidence indicates that circular RNAs (circRNAs) are promising biomarkers, as they play significant roles in the development of various cancers. The circular RNA MYLK (circMYLK) has been reported to be involved in the development of malignant tumours, including liver, prostate and bladder cancers. Nevertheless, the biological function of circMYLK in renal cell carcinoma (RCC) remains unclear. In this study, we observed that circMYLK is notably up-regulated in RCC. Increased circMYLK expression led to a larger tumour size, distant metastasis and poor prognosis of RCC patients. Moreover, circMYLK silencing repressed RCC growth and metastasis in vitro and in vivo. Mechanistically, circMYLK can capture miR-513a-5p to facilitate VEGFC expression and further promote the tumorigenesis of RCC cells. In summary, our findings demonstrate that circMYLK has an oncogenic role in RCC growth and metastasis by modulating miR-513a-5p/VEGFC signalling. Thus, circMYLK has potential as a diagnostic biomarker and therapeutic target in the treatment of RCC.

circRNA MYLK Accelerates Cervical Cancer via Up-Regulation of RHEB and Activation of mTOR Signaling

Background

Growing evidence directly suggested that circular RNAs (circRNAs) are crucial contributors in the course of cervical cancer (CC) onset and progression. Nevertheless, a large number of circRNAs have not been fully addressed in their function and underlying mechanisms during CC etiology.

Purpose

Our study focused on the function of circRNA MYLK (myosin light chain kinase), one novel tumor-related circRNA, in CC cell behaviors.

Methods

Firstly, we evaluated the expression profile of circMYLK in CC cells and in normal Ect1/E6E7 cell line. Moreover, the accurate function of circMYLK in CC cells was assessed via colony formation, CCK-8, EdU, and TUNEL assay. The association among circRNAs, miRNA, and target mRNAs was predicated by bioinformatics methods and validated in mechanical assays.

Results

We disclosed that circMYLK was up-regulated in CC cell lines and acted as a sponge of miR-1301-3p. Besides, downstream miR-1301-3p was capable of reversing circMYLK-mediated CC cell growth and apoptosis. Furthermore, we validated that circMYLK bound to miR-1301-3p as a sponge to upregulate RHEB (Ras homolog, mTORC1 binding) expression. As annotated in prior works, RHEB was responsible for mTOR signaling transduction. Therefore, we investigated whether circMYLK functioned its tumor-facilitating impact in CC through a RHEB-dependent mTOR signaling activation.

Conclusion

It was unveiled that circMYLK sponged miR-1301-3p to promote RHEB expression, which resulted in mTOR signaling activation and CC cell malignant growth.

Upregulation of Circular RNA Itchy E3 Ubiquitin Protein Ligase Inhibits Cell Proliferation and Promotes Cell Apoptosis Through Targeting MiR-197 in Prostate Cancer

Objective:

This study aimed to investigate the effect of circular RNA itchy E3 ubiquitin protein ligase on cell proliferation and apoptosis and to explore its target micro-RNAs in prostate cancer cells.

Methods:

Circular RNA itchy E3 ubiquitin protein ligase expression in human prostate cancer cells and normal prostate epithelial cells was determined by real time-quantitative polymerase chain reaction assay. Circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids (circular RNA itchy E3 ubiquitin protein ligase(+) group and control overexpression plasmids group were transfected with PC-3 cells. Rescue experiment was performed by transfection of circular RNA itchy E3 ubiquitin protein ligase overexpression and micro-197 overexpression plasmids (circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids/micro RNA (+) group) into PC-3 cells. Cell Counting Kit-8 and annexin V/propidium iodide assays were conducted to evaluate cell proliferation and apoptosis, respectively. Western blot was performed to determine the expressions of apoptotic-related markers.

Results:

Circular RNA itchy E3 ubiquitin protein ligase expression was decreased in DU 145, 22RV1, VCaP, and PC-3 cells compared to RWPE cells. In PC-3 cells, cell proliferation rate was reduced in circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids group compared to control overexpression plasmids group at 48 hours and 72 hours. Cell apoptosis rate was elevated in circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids group compared to control overexpression plasmids group at 48 hours, and Western blot showed the similar results. Micro RNA-197 but not micro RNA-31 or micro RNA-432 was the target micro-RNA of circular RNA itchy E3 ubiquitin protein ligase. In rescue experiments, cell proliferation rate was elevated, but apoptosis rate was reduced in circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids/micro RNA (+) group compared to circular RNA itchy E3 ubiquitin protein ligase overexpression plasmids group, indicating that circular RNA itchy E3 ubiquitin protein ligase upregulation inhibited cell proliferation but promoted apoptosis through downregulating micro RNA-197.

Conclusion:

Circular RNA itchy E3 ubiquitin protein ligase upregulation suppresses cell proliferation but promotes apoptosis through targeting micro RNA-197 in prostate cancer. Our study may provide a new insight for the treatment of prostate cancer.

Progress of research into circular RNAs in urinary neoplasms

Circular RNAs (circRNAs) are a large class of endogenous RNA that form a covalently closed continuous loop without 5′ or 3′ tails and are diffusely expressed in mammalian cells. Through the development of high-throughput sequencing, microarray, and bioinformatics analyses, recent studies have shown that the expression of circRNAs is dysregulated in human tumor tissues and cells, as well as in the blood of patients, and closely correlates with the development of tumors. circRNAs can regulate the progression of tumors through various mechanisms. An increasing number of studies have shown that circRNAs may play critical roles in the early diagnosis, targeted therapy, and prognostic prediction of cancer as biomarkers or therapeutic targets. This review briefly describes the definitions and functions of circRNAs, and the main content includes the most recent progress in research into their function, regulation, and clinical relevance to bladder, renal, and prostate cancers. We also provide some novel ideas regarding the treatment of these diseases.

Silencing circular RNA circZNF609 restrains growth, migration and invasion by up-regulating microRNA-186-5p in prostate cancer

Background: Prostate cancer (PC) fearfully impacts men's health. We explored the efficacy and mechanism of circular RNA circZNF609 (circZNF609) on colony formation, viability, apoptosis, migration and invasion and in PC cells. Methods: Colony formation, CCK-8, flow cytometry, migration and invasion assay were respectively used to detect the functions of circZNF609 and microRNA (miR)-186-5p on cell colony ability, viability, apoptosis, migration and invasion. circZNF609 and miR-186-5p expression were changed by cell transfection and tested by RT-qPCR. Moreover, Cleaved-Caspase-3, Cleaved-Caspase-9, matrix metalloproteinase-9 (MMP-9), Vimentin and relate-proteins of cell pathways were examined through Western blot. Results: circZNF609 was highly expressed at PC tissues. circZNF609 declined cell colony ability, viability, migration and invasion and caused apoptosis. Furthermore, circZNF609 negatively regulated miR-186-5p, miR-186-5p inhibitor could reverse impacts of circZNF609. Finally, circZNF609 restrained the YAP1 and AMPK pathways by up-regulating miR-186-5p. Conclusion: Silencing circZNF609 restrained growth, migration and invasion of PC cells by up-regulating miR-186-5p via YAP1 and AMPK pathways. Highlights circZNF609 is highly expressed in PC tissues; circZNF609 restrains cell growth, migration and invasion; circZNF609 exerts its function by up-regulating miR-186-5p; circZNF609 exerts its function by YAP1 and AMPK signaling pathways.

Circ_KATNAL1 regulates prostate cancer cell growth and invasiveness through the miR-145-3p/WISP1 pathway

Prostate cancer (PCa) is the second leading cause of death in men, and current studies have shown that circular RNAs (circRNAs) play important roles in its occurrence and development. Detection of circRNAs in PCa cells showed that circ_KATNAL1 is down-regulated, mainly located in the cytoplasm, and contains multiple binding sites of miR-145-3p, which is an anticancer miRNA. RNA immunoprecipitation with anti-AGO2 antibody, RNA pull-down assays with biotin-labeled circ_KATNAL1 probe or an miR-145-3p mimic, and dual luciferase reporter gene assays confirmed that circ_KATNAL1 binds directly to miR-145-3p in cells, and that WISP1, which is highly expressed in many types of tumors, is an important target gene of miR-145-3p. Circ_KATNAL1 and miR-145-3p promote each other's expression, and down-regulate the expression of the target gene WISP1. Both circ_KATNAL1 and miR-145-3p inhibit cell proliferation, invasiveness, and migration, down-regulate the expression of MMP-2 and MMP-9, promote cell apoptosis and the activation of caspase-3, caspase-8, caspase-9, and PARP, whereas WISP1 has the opposite effect, and the above-mentioned functions of circ_KATNAL1 were achieved through the miR-145-3p/WISP1 pathway. Therefore, circ_KATNAL1 plays an anticancer role in PCa cells through the miR-145-3p/WISP1 pathway, which could be an important target for the diagnosis and treatment of PCa.

Circular RNA ITCH suppressed prostate cancer progression by increasing HOXB13 expression via spongy miR-17-5p

BACKGROUND

Circular RNA Itchy E3 ubiquitin protein ligase (Circ-ITCH) is significantly down-regulated in various kinds of tumors, however, the mechanisms of action and functions of circITCH gene in prostate cancer (PC) are still under investigation. The mail goal of this research was to study the functional role of Circ-ITCH gene in prostate cancer and to illuminate the function role of circ-ITCH gene in prostate cancer by targeting miR-17-5p/HOXB13.

METHODS

RT-qPCR was applied to measure the expression level of circ-ITCH and miR-17-5p in PC cell lines and tissues. CCK-8, colony formation, Brdu incorporation labeling and flow cytometry assays were applied to detect the effects of circ-ITCH and miR-17-5p on proliferation and cell apoptosis. Target gene prediction and screening, luciferase reporter gene assays were utilized to assess downstream target genes of miR-17-5p and Circ-ITCH. The protein and expression of HOXB13 gene were measured by Western blotting and RT-qPCR.

RESULTS

CircITCH was significantly reduced in PC cell lines and tissues. Low circITCH expression level was highly related with preoperative PSA, tumor stage and Gleason score. Overexpression of circITCH can inhibit the malignant phenotype of prostate cancer. There was a high negative relationship between the expression level of microRNA-17-5p and circITCH in PC tissues, however, there existed a positive relationship between the expression of HOXB13 and circITCH. CircITCH acted as a sponge of miR-17-5p to increase HOXB13 gene expression. In addition, miR-17-5p overexpression or HOXB13 silencing can reduce the carcinogenic effects of circICCH in prostate cancer.

CONCLUSION

CircITCH promoted prostate cancer progression by regulating the HOXB13/miR-17-5p axis, and circITCH have a potential usage as therapeutic target for PC tumors.

A New Era of Prostate Cancer Precision Medicine

Prostate cancer is the second most common male cancer affecting Western society. Despite substantial advances in the exploration of prostate cancer biomarkers and treatment strategies, men are over diagnosed with inert prostate cancer, while there is also a substantial mortality from the invasive disease. Precision medicine is the management of treatment profiles across different cancers predicting therapies for individual cancer patients. With strategies including individual genomic profiling and targeting specific cancer pathways, precision medicine for prostate cancer has the potential to impose changes in clinical practices. Some of the recent advances in prostate cancer precision medicine comprise targeting gene fusions, genome editing tools, non-coding RNA biomarkers, and the promise of liquid tumor profiling. In this review, we will discuss these recent scientific advances to scale up these approaches and endeavors to overcome clinical barriers for prostate cancer precision medicine.

CircLMTK2 acts as a tumor suppressor in prostate cancer via regulating the expression of microRNA-183

BACKGROUND

Prostate cancer (PCa) is one of the commonest male urinary and reproductive system malignancies with high morbidity and mortality. circLMTK2 was reported as a tumor suppressor, therefore, we attempted to investigate the potential mechanism of circLMTK2 in PCa.

METHODS

qRT-PCR was employed to examine the expressions of circLMTK2 and miR-183. Afterwards, cell transfection was conducted for overexpressing circLMTK2 and miR-183 in LNCaP and PC3 cells, and silencing circLMTK2 in RWPE1 cells. Then, CCK-8 assay, BrdU, transwell assay, flow cytometry and western blot were respectively conducted to examine the variations of cell growth and metastasis, as well as apoptosis. The expressions of key proteins involved in Wnt/β-catenin and PI3K/AKT pathways were further investigated utilizing western blot.

RESULTS

circLMTK2 was lowly expressed in tumor tissues. circLMTK2 overexpression suppressed cell proliferation and metastasis, however promoted cell apoptosis in LNCaP and PC3 cells. circLMTK2 knockdown enhanced cell viability, proliferation, migration and invasion, while had no significant influences on apoptosis of RWPE1 cells. Further experiments verified that miR-183 up-regulation counteracted the influences triggered by circLMTK2 overexpression in LNCaP and PC3 cells. Besides, it markedly promoted the viability, proliferation, migration and invasion of LNCaP cells, however had no significant influence on cell apoptosis. Moreover, the inhibitory effects on Wnt/β-catenin and PI3K/AKT pathways evoked by circLMTK2 overexpression were diminished by miR-183 up-regulation in LNCaP and PC3 cells.

CONCLUSION

These outcomes illustrated that circLMTK2 overexpression exerts an anti-tumor effects through down-regulating the expression of miR-183.

Circ-MTO1 correlates with favorable prognosis and inhibits cell proliferation, invasion as well as miR-17-5p expression in prostate cancer

BACKGROUND

This study aimed to investigate circular RNA-mitochondrial tRNA translation optimization 1 (circ-MTO1) expression in tumor tissue and its correlation with clinical characteristics and survival profiles, as well as its effect on cancer cell functions in prostate cancer.

METHODS

A total of 298 primary prostate cancer patients were included. Reverse transcription-quantitative polymerase chain reaction was conducted to evaluate circ-MTO1 expression in tumor tissue and paired adjacent tissue. Disease-free survival (DFS) and overall survival (OS) were recorded. In in vitro experiment, prostate cancer cells were transfected with circ-MTO1 over-expression and negative-control over-expression plasmids. Then cell proliferation, cell invasion and miR-630 as well as miR-17-5p expressions in prostate cancer cells were detected.

RESULTS

Circular RNA-mitochondrial tRNA translation optimization 1 expression was downregulated in tumor tissue compared with paired adjacent tissue (P < .001) in patients with prostate cancer. Circ-MTO1 high expression in tumor tissue was correlated with decreased pathological T stage (P = .001) as well as lower pathological N stage (P = .020). As for survival profiles, the DFS (P = .006) and OS (P = .018) were both longer in patients who had circ-MTO1 high expression compared with patients who had circ-MTO1 low expression. In addition, circ-MTO1 high expression independently predicted favorable DFS and OS. Besides, further in vitro experiments illustrated that circ-MTO1 inhibited proliferation (P < .05) and invasion (P < .05) as well as downregulated miR-17-5p expression in prostate cancer cells (P < .05).

CONCLUSION

Circ-MTO1 correlates with decreased pathological T/N stage and favorable survival profiles, and it also inhibits cell proliferation, invasion as well as miR-17-5p expression in prostate cancer.

Circular RNA MYLK serves as an oncogene to promote cancer progression via microRNA-195/cyclin D1 axis in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) is a common aggressive head and neck cancer. Circular RNAs (circRNAs) are implicated in numerous physiological and pathological processes, including tumorigenesis. The present study aimed to investigate the expression profile and biological role of circMYLK in LSCC. We found that circMYLK was highly expressed in LSCC tissues and cell lines. circMYLK overexpression promoted LSCC cell proliferation and G₁/S cell cycle transition; whereas circMYLK knockdown had the contrary effects. Mechanistically, circMYLK can serve as a competing endogenous RNA for miR-195 to increase cyclin D1 expression in LSCC, and rescue experiments further showed that restoration of miR-195 could block the oncogenic role of circMYLK in LSCC. In conclusion, our findings indicate that the circMYLK/miR-195/cyclin D1 regulatory axis could affect the proliferation and cell cycle progression of LSCC cells, and may provide a novel therapeutic target for the treatment of LSCC.

Circular RNAs in cancer: new insights into functions and implications in ovarian cancer

Circular RNAs (circRNAs) are a class of long non-coding RNAs (lncRNAs) which have a circular and closed loop structure. They are ubiquitous, stable, conserved and diverse RNA molecules with a range of activities such as translation and splicing regulation, which are able to interacting with RNA-binding proteins and specially miRNA sponge. The expression patterns of the circRNAs exhibited tissue specificity and also, step and stage specificity. Accumulating evidences approved the critical role of circular RNAs in many cancers such as ovarian cancer. Given that these molecules exert their effects through multiple cellular and molecular mechanisms (i.e., angiogenesis, apoptosis, growth, and metastasis) which are involved in cancer pathogenesis, circular RNAs, in particular, act by controlling cell proliferation in ovarian cancer, so that, it has been shown that the deregulation of these molecules is associated with initiation and progression of ovarian cancer. Therefore, they are attractive molecules which have introduced them as cancer biomarkers. Moreover, they could be used as new therapeutic candidates for developing novel treatment strategies. Here, for first time, we have provided a comprehensive review on the recent knowledge of circular RNAs and their pathological roles in the ovarian cancer.

Expression of KIF18A Is Associated with Increased Tumor Stage and Cell Proliferation in Prostate Cancer

Background

The role of KIF18A in tumorigenesis and tumor development has been well studied in several cancers, but not in prostate cancer. In this study, we investigated the potential prognostic utility of KIF18A and its role in prostate cancer progression.

Material/Methods

We collected prostate cancer and paracancerous tissue samples from the same patient. Immunohistochemical staining was performed to investigate the KIF18A expression levels in the clinical sample. The Cancer Genome Atlas (TCGA) database was analyzed via a bioinformatics approach to gain insight into the relationship between KIF18A expression and prognosis. We examined the effect of KIF18A knockdown on PC-3 cell proliferation via colony formation and MTT assays. Flow cytometry was used to assess the effect of KIF18A knockdown on PC-3 cell apoptosis. Transwell invasion assay was performed to assess whether KIF18A affects the invasion ability of PC-3 cells.

Results

The KIF18A protein level was higher in PCa tissue than in paracancerous tissue. The In addition, upregulated KIF18A suggested a poor tumor stage and prognosis for prostate cancer patients. Our in vitro experiments demonstrated that KIF18A knockdown in PC-3 cells significantly inhibited proliferation and metastasis.

Conclusions

High KIF18A expression in prostate cancer patients predicts a poor prognosis. KIF18A knockdown inhibits prostate cell proliferation and metastasis. Therefore, this study confirms the usefulness of KIF18A as an oncological prognostic indicator and a potential therapeutic target for prostate cancer.