Circular RNA CirCHIPK3 promotes cell proliferation and invasion of breast cancer by sponging miR-193a/HMGB1/PI3K/AKT axis

Mechanistic insights into circRNA-mediated regulation of PI3K signaling pathway in glioma progression

Circular RNAs (CircRNAs) are non-coding RNAs (ncRNAs) characterized by a stable circular structure that regulates gene expression at both transcriptional and post-transcriptional levels. They play diverse roles, including protein interactions, DNA methylation modification, protein-coding potential, pseudogene creation, and miRNA sponging, all of which influence various physiological processes. CircRNAs are often highly expressed in brain tissues, and their levels vary with neural development, suggesting their significance in nervous system diseases such as gliomas. Research has shown that circRNA expression related to the PI3K pathway correlates with various clinical features of gliomas. There is an interact between circRNAs and the PI3K pathway to regulate glioma cell processes such as proliferation, differentiation, apoptosis, inflammation, angiogenesis, and treatment resistance. Additionally, PI3K pathway-associated circRNAs hold potential as biomarkers for cancer diagnosis, prognosis, and treatment. In this study, we reviewed the latest advances in the expression and cellular roles of PI3K-mediated circRNAs and their connections to glioma carcinogenesis and progression. We also highlighted the significance of circRNAs as diagnostic and prognostic biomarkers and therapeutic targets in glioma.

Imaging and quantification of human and viral circular RNAs

We present a robust approach for cellular detection, imaging, localization, and quantification of human and viral encoded circular RNAs (circRNA) using amplified fluorescence in situ hybridization (ampFISH). In this procedure, a pair of hairpin probes bind next to each other at contiguous stretches of sequence and then undergo a conformational reorganization which initiates a target-dependent hybridization chain reaction (HCR) resulting in deposition of an amplified fluorescent signal at the site. By harnessing the capabilities of both ampFISH and single-molecule FISH (smFISH), we selectively identified and imaged circular RNAs and their linear counterparts derived from the human genome, SARS-CoV-2 (an RNA virus), and human cytomegalovirus (HCMV, a DNA virus). Computational image processing facilitated accurate quantification of circular RNA molecules in individual cells. The specificity of ampFISH for circular RNA detection was confirmed through an in situ RNase R treatment that selectively degrades linear RNAs without impacting circular RNAs. The effectiveness of circular RNA detection was further validated by using ampFISH probes with mismatches and probe pairs that do not bind to the continuous sequence in their target RNAs but instead bind at segregated sites. An additional specificity test involved probes against the negative strands of the circular RNA sequence, absent in the cell. Importantly, our technique allows simultaneous detection of circular RNAs and their linear counterparts within the same cell with single molecule sensitivity, enabling explorations of circular RNA biogenesis, subcellular localization, and functions.

Supramolecular Nanoparticles of Histone and Hyaluronic Acid for Co-Delivery of siRNA and Photosensitizer In Vitro

Small interfering RNA (siRNA) has significant potential as a treatment for cancer by targeting specific genes or molecular pathways involved in cancer development and progression. The addition of siRNA to other therapeutic strategies, like photodynamic therapy (PDT), can enhance the anticancer effects, providing synergistic benefits. Nevertheless, the effective delivery of siRNA into target cells remains an obstacle in cancer therapy. Herein, supramolecular nanoparticles were fabricated via the co-assembly of natural histone and hyaluronic acid for the co-delivery of HMGB1-siRNA and the photosensitizer chlorin e6 (Ce6) into the MCF-7 cell. The produced siRNA-Ce6 nanoparticles (siRNA-Ce6 NPs) have a spherical morphology and exhibit uniform distribution. In vitro experiments demonstrate that the siRNA-Ce6 NPs display good biocompatibility, enhanced cellular uptake, and improved cytotoxicity. These outcomes indicate that the nanoparticles constructed by the co-assembly of histone and hyaluronic acid hold enormous promise as a means of siRNA and photosensitizer co-delivery towards synergetic therapy.

KFDAE: CircRNA-Disease Associations Prediction Based on Kernel Fusion and Deep Auto-Encoder

CircRNA has been proved to play an important role in the diseases diagnosis and treatment. Considering that the wet-lab is time-consuming and expensive, computational methods are viable alternative in these years. However, the number of circRNA-disease associations (CDAs) that can be verified is relatively few, and some methods do not take full advantage of dependencies between attributes. To solve these problems, this paper proposes a novel method based on Kernel Fusion and Deep Auto-encoder (KFDAE) to predict the potential associations between circRNAs and diseases. Firstly, KFDAE uses a non-linear method to fuse the circRNA similarity kernels and disease similarity kernels. Then the vectors are connected to make the positive and negative sample sets, and these data are send to deep auto-encoder to reduce dimension and extract features. Finally, three-layer deep feedforward neural network is used to learn features and gain the prediction score. The experimental results show that compared with existing methods, KFDAE achieves the best performance. In addition, the results of case studies prove the effectiveness and practical significance of KFDAE, which means KFDAE is able to capture more comprehensive information and generate credible candidate for subsequent wet-lab.

The PI3K/AKT/mTOR signaling pathway in breast cancer: Review of clinical trials and latest advances

Breast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer mortality in women. As the phosphatidylinositol 3-kinase (PI3K) signaling pathway is involved in a wide range of physiological functions of cells including growth, proliferation, motility, and angiogenesis, any alteration in this axis could induce oncogenic features; therefore, numerous preclinical and clinical studies assessed agents able to inhibit the components of this pathway in BC patients. To the best of our knowledge, this is the first study that analyzed all the registered clinical trials investigating safety and efficacy of the PI3K/AKT/mTOR axis inhibitors in BC. Of note, we found that the trends of PI3K inhibitors in recent years were superior as compared with the inhibitors of either AKT or mTOR. However, most of the trials entering phase III and IV used mTOR inhibitors (majorly Everolimus) followed by PI3K inhibitors (majorly Alpelisib) leading to the FDA approval of these drugs in the BC context. Despite favorable efficacies, our analysis shows that the majority of trials are utilizing PI3K pathway inhibitors in combination with hormone therapy and chemotherapy; implying monotherapy cannot yield huge clinical benefits, at least partly, due to the activation of compensatory mechanisms. To emphasize the beneficial effects of these inhibitors in combined-modal strategies, we also reviewed recent studies which investigated the conjugation of nanocarriers with PI3K inhibitors to reduce harmful toxicities, increase the local concentration, and improve their efficacies in the context of BC therapy.

The potential of circHIPK3 as a biomarker in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by leukocytosis and left shift. The primary molecular alteration is the BCR::ABL1, chimeric oncoprotein with tyrosine kinase activity, responsible for the initial oncogenesis of the disease. Therapy of CML was revolutionized with the advent of tyrosine kinase inhibitors, but it is still not considered curative and may present resistance and serious adverse effects. Discoveries in CML inaugurated a new era in cancer treatment and despite all the advances, a new biomarker is needed to detect resistance and adverse effects. Circular RNAs (circRNAs) are a special type of non-coding RNA formed through a process called backsplicing. The majority of circRNAs are derived from protein-coding genes. CircHIPK3 is formed from the second exon of the HIPK3 gene and has been found in various pathologies, including different types of cancer. New approaches have demonstrated the potential of circular RNAs in cancer research, and circHIPK3 has shown promising results. It is often associated with cellular regulatory pathways, suggesting an important role in the molecular dynamics of tumors. The identification of biomarkers is an important tool for therapeutic improvement; thus we review the role of circHIPK3 and its potential as a biomarker in CML.

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.

HMGB1 in the interplay between autophagy and apoptosis in cancer

Lysosome-mediated autophagy and caspase-dependent apoptosis are dynamic processes that maintain cellular homeostasis, ensuring cell health and functionality. The intricate interplay and reciprocal regulation between autophagy and apoptosis are implicated in various human diseases, including cancer. High-mobility group box 1 (HMGB1), a nonhistone chromosomal protein, plays a pivotal role in coordinating autophagy and apoptosis levels during tumor initiation, progression, and therapy. The regulation of autophagy machinery and the apoptosis pathway by HMGB1 is influenced by various factors, including the protein's subcellular localization, oxidative state, and interactions with binding partners. In this narrative review, we provide a comprehensive overview of the structure and function of HMGB1, with a specific focus on the interplay between autophagic degradation and apoptotic death in tumorigenesis and cancer therapy. Gaining a comprehensive understanding of the significance of HMGB1 as a biomarker and its potential as a therapeutic target in tumor diseases is crucial for advancing our knowledge of cell survival and cell death.

circ_0058063 promotes breast cancer progression by upregulating DLGAP5 via sponging miR-557

OBJECTIVE

Accumulating evidence indicates that circular RNAs (circRNAs) contribute to breast cancer (BC) development and progression. However, the role of circ_0058063 in BC and its underlying molecular processes remain unclear.

METHODS

The expression of circ_0058063, miR-557, and DLGAP5 in BC tissues and cells was determined using real time quantitative PCR or western blotting. The functions of circ_0058063 in BC cells were detected using CCK-8, Transwell, caspase-3 activity, and xenograft tumor assays. The specific binding of circ_0058063/miR-557 and DLGAP5/miR-557 was verified using RNA immunoprecipitation (RIP) and dual-luciferase reporter assays.

RESULTS

circ_0058063 expression was upregulated in BC tissues and cells. circ_0058063 knockdown inhibited proliferation and migration but promoted apoptosis in MCF-7 and MDA-MB-231 cells in vitro. In vivo studies further validated that the knockdown of circ_0058063 repressed tumor growth. Mechanistically, circ_0058063 directly sponged miR-557 and negatively regulated its expression. Additionally, miR-557 inhibition reversed the tumor-suppressive effects of the circ_0058063 knockdown on the survival of MDA-MB-231 and MCF-7 cells. Moreover, miR-557 directly targeted DLGAP5. DLGAP5 knockdown suppressed MCF-7 and MDA-MB-231 cell growth, and these effects were reversed by miR-557 downregulation.

CONCLUSION

Our findings verify that circ_0058063 acts as a sponge for miR-557 to upregulate DLGAP5 expression. These findings suggest that the circ_0058063/miR-557/DLGAP5 axis is an important regulator of oncogenic function and may be a promising therapeutic target for BC.

Dual effects of circRNA in thyroid and breast cancer

CircRNA, the latest research hotspot in the field of RNA, is a special non-coding RNA molecule, which is unable to encode proteins and bind polyribosomes. As a regulatory molecule, circRNA participates in cancer cell generation and progression mainly through the mechanism of competitive endogenous RNA. In numerous regulated cancer organs, the thyroid and breast are both endocrine organs, and both are regulated by the hypothalamic pituitary gland axis. Thyroid cancer (TC) and breast cancer (BC) are both sexually prevalent in women and both are affected by hormones, thus they are intrinsically linked. In addition, recent epidemiological surveys have found that, early metastasis and recurrence of breast cancer remain the main cause of survival in breast cancer patients. Although at home and abroad, studies have shown that new targeted anti-tumor drugs with numerous tumor markers are gradually being used in the clinic, evidence for potential molecular mechanisms affecting its prognosis lacks clinical studies. Therefore, we search the relevant literature, and based on the latest domestic and international consensus, review the molecular mechanisms and regulation relevance of circRNA, compare the difference of the same circRNA in two tumors, to more deeply understand and lay the foundation for future clinical diagnostic, therapeutic and prognostic studies in large samples.

The emerging regulatory roles of non-coding RNAs associated with glucose metabolism in breast cancer

Altered energy metabolism is one of the hallmarks of tumorigenesis and essential for fulfilling the high demand for metabolic energy in a tumor through accelerating glycolysis and reprogramming the glycolysis metabolism through the Warburg effect. The dysregulated glucose metabolic pathways are coordinated not only by proteins coding genes but also by non-coding RNAs (ncRNAs) during the initiation and cancer progression. The ncRNAs are responsible for regulating numerous cellular processes under developmental and pathological conditions. Recent studies have shown that various ncRNAs such as microRNAs, circular RNAs, and long noncoding RNAs are extensively involved in rewriting glucose metabolism in human cancers. In this review, we demonstrated the role of ncRNAs in the progression of breast cancer with a focus on outlining the aberrant expression of glucose metabolic pathways. Moreover, we have discussed the existing and probable future applications of ncRNAs to regulate energy pathways along with their importance in the prognosis, diagnosis, and future therapeutics for human breast carcinoma.

Epigenetic regulation of circ-HIPK3, circ-PVT1, miR-25, and miR-149 in radiosensitivity of breast cancer

Assessing the radiosensitivity of cells before administering radiation therapy (RT) to individuals diagnosed with breast cancer (BC) can facilitate the selection of appropriate treatment regimens and minimize the incidence of adverse side effects in patients undergoing radiation exposure. In this research, blood samples were obtained from 60 women who had been diagnosed with Invasive Ductal Carcinoma (IDC) Breast Cancer. The average age of the patients was 47 ± 9.93. Additionally, the study incorporated 20 healthy women, with an average age of 44.43 ± 6.7. A standard G2 assay was conducted to predict the cellular response to radiation. Out of the 60 samples, the G2 assay identified 20 patients with breast cancer who exhibited radiosensitivity. Hence, molecular investigations were ultimately conducted on two equivalent cohorts comprising 20 subjects each, one with and the other without cellular radiosensitivity. The expression levels of miR-149, miR-25, circ-PVT1, and circ-HIPK3 in peripheral blood mononuclear cells (PBMCs) were evaluated using quantitative polymerase chain reaction (qPCR). Receiver Operating Characteristic (ROC) curves were used to evaluate the sensitivity and specificity of the RNAs. An analysis using binary logistic regression was performed to investigate the relationship between RNAs and both BC and cellular radiosensitivity (CR) in patients with BC. The findings revealed a significant upregulation of Circ-HIPK3 and circ-PVT1 in individuals diagnosed with BC. The levels of Circ-HIPK3 and Circ-PVT1 were found to be directly associated with CR in BC patients. The analysis of the ROC curve demonstrated that circ-HIPK3 and circ-PVT1 exhibit favorable specificity and sensitivity in accurately predicting both BC and CR in patients with BC. The findings from the binary logistic regression analysis demonstrated that circ-HIPK3 and circ-PVT1 were effective predictors of both BC and CR. The ROC curve and binary logistic regression analyses provide evidence that miR-25 is a reliable predictor for BC patients exclusively. Our research has demonstrated that circ-HIPK3, circ-PVT1, and miR-25 may be involved in BC regulatory processes. The circular RNAs Circ-HIPK3 and circ-PVT1, as well as miR-25, among other significant biomarkers, could potentially serve as promising biomarkers for predicting BC. Furthermore, Circ-HIPK3 and circ-PVT1 have the potential to serve as biomarkers for predicting CR in BC patients.

Development of a circHIPK3-based ceRNA network and identification of mRNA signature in breast cancer patients harboring BRCA mutation

Background

Exploring the regulatory network of competing endogenous RNAs (ceRNAs) as hallmarks for breast cancer development has great significance and could provide therapeutic targets. An mRNA signature predictive of prognosis and therapy response in BRCA carriers was developed according to circular RNA homeodomain-interacting protein kinase 3 (circHIPK3)-based ceRNA network.

Method

We constructed a circHIPK3-based ceRNA network based on GSE173766 dataset and identified potential mRNAs that were associated with BRCA mutation patients within this ceRNA network. A total of 11 prognostic mRNAs and a risk model were identified and developed by univariate Cox regression analysis and the LASSO regression analysis as well as stepAIC method. Genomic landscape was treated by mutect2 and fisher. Immune characteristics was analyzed by ESTIMATE, MCP-counter. TIDE analysis was conducted to predict immunotherapy. The clinical treatment outcomes of BRCA mutation patients were assessed using a nomogram. The proliferation, migration and invasion in breast cancer cell lines were examined using CCK8 assay and transwell assay.

Result

We found 241 mRNAs within the circHIPK3-based ceRNA network. An 11 mRNA-based signature was identified for prognostic model construction. High risk patients exhibited dismal prognosis, low response to immunotherapy, less immune cell infiltration and tumor mutation burden (TMB). High-risk patients were sensitive to six anti-tumor drugs, while low-risk patient were sensitive to 47 drugs. The risk score was the most effective on evaluating patients' survival. The robustness and good prediction performance were validated in The Cancer Genome Atlas (TCGA) dataset and immunotherapy datasets, respectively. In addition, circHIPK3 mRNA level was upregulated, and promoted cell viability, migration and invasion in breast cancer cell lines.

Conclusion

The current study could improve the understanding of mRNAs in relation to BRCA mutation and pave the way to develop mRNA-based therapeutic targets for breast cancer patients with BRCA mutation.

CircRNAs in colorectal cancer: potential biomarkers and therapeutic targets

Globally, colorectal cancer (CRC) is the third most prevalent cancer and the second leading cause of cancer-related deaths. Circular RNAs (circRNAs) are single-stranded RNA with covalently closed-loop structures and are highly stable, conserved, and abundantly expressed in various organs and tissues. Recent research found abnormal circRNA expression in CRC patients' blood/serum, cells, CRC tissues, and exosomes. Furthermore, mounting data demonstrated that circRNAs are crucial to the development of CRC. CircRNAs have been shown to exert biological functions by acting as microRNA sponges, RNA-binding protein sponges, regulators of gene splicing and transcription, and protein/peptide translators. These characteristics make circRNAs potential markers for CRC diagnosis and prognosis, potential therapeutic targets, and circRNA-based therapies. However, further studies are still necessary to improve the understanding of the roles and biological mechanisms of circRNAs in the development of CRC. In this review, up-to-date research on the role of circRNAs in CRC was examined, focusing on their potential application in CRC diagnosis and targeted therapy, which would advance the knowledge of the functions of circRNAs in the development and progression of CRC.

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.

PI3K/AKT/mTOR signaling pathway modulation by circular RNAs in breast cancer progression

The PI3K/Akt/mTOR signaling pathway is responsible for many cellular behaviors, including survival, growth, and proliferation. A newly identified RNA, circular RNA (circRNA), plays a crucial role in the regulation of gene expression. The upregulation of the PI3K/Akt pathway through dysregulated circRNAs promotes breast tumor initiation, growth, and progression. The dysregulation of PI3K/Akt-regulating circRNAs seems to be directly correlated with breast cancer clinical features, including overall survival, tumor size, cancer stage, and lymph node metastasis. In addition, targeting these circRNAs may be a promising option in cancer-targeted therapy. Understanding the molecular pathogenesis of the circRNA-PI3K/AKT axis may give the insight to develop new therapeutic and diagnostic approaches for breast cancer therapy. Here we reviewed the expression and functions of PI3K/AKT-regulating circRNAs, and their correlation with breast cancer clinical features. In addition, the potential of PI3K/AKT-regulating circRNAs as diagnostic/prognostic biomarkers or therapeutic targets was discussed.

Exosomal circular RNAs: New player in breast cancer progression and therapeutic targets

Breast cancer is the most prevalent type of malignancy among women. Exosomes are extracellular vesicles of cell membrane origin that are released via exocytosis. Their cargo contains lipids, proteins, DNA, and different forms of RNA, including circular RNAs. Circular RNAs are new class of non-coding RNAs with a closed-loop shape involved in several types of cancer, including breast cancer. Exosomes contained a lot of circRNAs which are called exosomal circRNAs. By interfering with several biological pathways, exosomal circRNAs can have either a proliferative or suppressive role in cancer. The involvement of exosomal circRNAs in breast cancer has been studied with consideration to tumor development and progression as well as its effects on therapeutic resistance. However, its exact mechanism is still unclear, and there have not been available clinical implications of exo-circRNAs in breast cancer. Here, we highlight the role of exosomal circRNAs in breast cancer progression and to highlight the most recent development and potential of circRNAas therapeutic targets and diagnostics for breast cancer.

Understanding the Dual Roles of CircHIPK3 in Tumorigenesis and Tumor Progression

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

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

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

Eriodictyol inhibits breast carcinogenesis by targeting circ_0007503 and repressing PI3K/Akt pathway

BACKGROUND

Eriodictyol in citrus fruits, Eriodictyon californicum and several Chinese herbal medicines shows great promise for chronic disease prevention, including cancers. However, its role in chemopreventive activities against breast carcinogenesis is unknown.

PURPOSE

In the present study, we investigated the chemopreventive effect and the underlying mechanism of eriodictyol on carcinogens-induced breast carcinogenesis in vivo and in vitro.

METHODS

The carcinogenic transformation in MCF10A cells was induced by the environmental carcinogens in vitro. The chemopreventive effect in vivo was evaluated by using the experimental model of 1-methyl-1-nitrosourea (MNU)-induced mammary tumorigenesis in rats. The activation of the PI3K/Akt pathway was detected by western blot assay; the levels of circular RNAs (circRNAs) were measured by qRT-PCR.

RESULTS

First, eriodictyol significantly reduces cells viability and induces apoptosis in breast cancer cells in a dose-dependent manner in vitro (P < 0.05). Next, eriodictyol could effectively suppress environmental carcinogens-induced acquisition of carcinogenic properties in human breast epithelial cell MCF10A (P < 0.05). In vivo, eriodictyol administration reduces the incidence of mammary tumor by 50% in carcinogen-treated female rats (P < 0.05). Further study revealed that eriodictyol represses the PI3K/Akt signaling pathway and down-regulates the level of circ_0007503 in breast cancer cells and in breast carcinogenesis (P < 0.01). When the effect of eriodictyol on circ_0007503 was blocked by transfection of a circ_0007503 over-expression plasmid, the cytotoxic effects and the suppression of the PI3K/Akt pathway of eriodictyol in breast cancer cells were significantly reduced (P < 0.05).

CONCLUSION

Our data indicated that eriodictyol could effectively suppress breast carcinogenesis in vitro and in vivoThe mechanism may be attributed to targeting circ_0007503 and inhibiting PI3K/Akt pathway.

Circular RNA circ_0006089 promotes the progression of gastric cancer by regulating the miR-143-3p/PTBP3 axis and PI3K/AKT signaling pathway

OBJECTIVES

Circular RNAs (circRNAs) play pivotal roles in malignancies including gastric cancer (GC). We aimed to investigate the biological function and regulatory mechanism of circ_0006089 in GC.

METHODS

Circ_0006089, microRNA (miR)-143-3p, and polypyrimidine tract-binding protein 3 (PTBP3) expressions were measured via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in GC cell lines. Cell proliferative capacity was determined by colony formation and CCK-8 assays. Flow cytometry was employed for measuring cell apoptosis. Cell invasion and migration were measured via transwell and wound-healing assays. Western blot analysis was utilized for detecting protein expressions of E-cadherin, N-cadherin, vimentin, PTBP3, PI3K, p-PI3K, AKT, and p-AKT. Dual-reporter luciferase analysis was conducted to confirm the association between miR-143-3p and circ_0006089 or PTBP3. The role of circ_0006089 in vivo was detected via establishing a mice xenograft model.

RESULTS

Circ_0006089 expression was increased in GC. Circ_0006089 downregulation suppressed the proliferation and metastasis and induced apoptosis of GC cells, which was counteracted by miR-143-3p inhibition or PTBP3 overexpression. In addition, circ_0006089 overexpression could promote GC progression. MiR-143-3p specially bound to circ_0006089 and PTBP3 was targeted by miR-143-3p. Moreover, circ_0006089 could regulate PTBP3 expression and the PI3K/AKT pathway by sponging miR-143-3p. Circ_0006089 knockdown also suppressed tumor growth.

CONCLUSION

Circ_0006089 regulated miR-143-3p/PTBP3/PI3K/AKT pathway to facilitate GC progression.

Breast cancer derived exosomes promoted angiogenesis of endothelial cells in microenvironment via circHIPK3/miR-124-3p/MTDH axis

Circular RNAs (circRNAs) are important contents in exosomes, which can regulate peripheral cell functions, thus influencing the tumor microenvironment. This work investigated the mechanisms underlying the angiogenesis in peripheral human endothelial cells (ECs) mediated by the breast cancer (BC) cells derived exosomal circRNAs and aimed to explore the biomarkers for the anti-angiogenesis therapy for BC.The BC cell derived exosomes were extracted and the expression level and the circular formation of HIPK3 enclosed was determined. To examine the impact of this exosomal circRNA on ECs, cell viability and tube formation were determined in recipient cells co-cultured with exosomes or transfected with circHIPK3 and the related controls. Target microRNAs (miRNAs) for circHIPK3 and target genes for miRNAs were predicted and confirmed by multiple assays like dual luciferase reporter assay, western blot, and qPCR assays. The existence of the circHIPK3/miR-124-3p/MTDH axis were further confirmed with rescue experiment in mice xenograft model.HIPK3s were mainly in forms of circRNAs and were highly expressed in the BC cell derived exosomes, which could be absorbed by the recipient ECs. The cell viability and angiogenesis in ECs were enhanced when treated with circHIPK3s and decreased when treated with circHIPK3-si. Furthermore, MTDH was proved to be the responsible gene in this process which was regulated by miR-124-3p, the local miRNA sponged by the exosomal circHIPK3.circHIPK3 enclosed in the BC cell-derived exosomes enhanced MTDH expression in the endothelial cell by sponging miR-124-3p, favoring the tube formation in ECs, which might serve as a therapeutic target for anti-angiogenesis therapy for breast cancer.

Circular RNAs as Potential Biomarkers in Breast Cancer

Due to the high heterogeneity and initially asymptomatic nature of breast cancer (BC), the management of this disease depends on imaging together with immunohistochemical and molecular evaluations. These tests allow early detection of BC and patient stratification as they guide clinicians in prognostication and treatment decision-making. Circular RNAs (circRNAs) represent a class of newly identified long non-coding RNAs. These molecules have been described as key regulators of breast carcinogenesis and progression. Moreover, circRNAs play a role in drug resistance and are associated with clinicopathological features in BC. Accumulating evidence reveals a clinical interest in deregulated circRNAs as diagnostic, prognostic and predictive biomarkers. Furthermore, due to their covalently closed structure, circRNAs are highly stable and easily detectable in body fluids, making them ideal candidates for use as non-invasive biomarkers. Herein, we provide an overview of the biogenesis and pleiotropic functions of circRNAs, and report on their clinical relevance in BC.

miR-193a-3p increases glycolysis under hypoxia by facilitating Akt phosphorylation and PFKFB3 activation in human macrophages

Human macrophages infiltrating hypoxic regions alter their metabolism, because oxygen becomes limited. Increased glycolysis is one of the most common cellular adaptations to hypoxia and mostly is regulated via hypoxia-inducible factor (HIF) and RAC-alpha serine/threonine–protein kinase (Akt) signaling, which gets activated under reduced oxygen content. We noticed that micro RNA (miR)-193a-3p enhances Akt phosphorylation at threonine 308 under hypoxia. In detail, miR-193a-3p suppresses the protein abundance of phosphatase PTC7 homolog (PPTC7), which in turn increases Akt phosphorylation. Lowering PPTC7 expression by siRNA or overexpressing miR-193a-3p increases Akt phosphorylation. Vice versa, inhibition of miR-193a-3p attenuates Akt activation and prevents a subsequent increase of glycolysis under hypoxia. Excluding effects of miR-193a-3p and Akt on HIF expression, stabilization, and function, we noticed phosphorylation of 6 phosphofructo-2-kinase/fructose 2,6-bisphosphatase PFKFB3 in response to the PI3K/Akt/mTOR signaling cascade. Inhibition of PFKFB3 blocked an increased glycolytic flux under hypoxia. Apparently, miR-193a-3p balances Akt phosphorylation and dephosphorylation by affecting PPTC7 protein amount. Suppression of PPTC7 increases Akt activation and phosphorylation of PFKFB3, which culminates in higher rates of glycolysis under hypoxia.

HMGB1 induces radioresistance through PI3K/AKT/ATM pathway in esophageal squamous cell carcinoma

BACKGROUND

To explore the effect of HMGB1 on the radio-sensitivity of esophageal cancer cells through regulating the PI3K/Akt/ATM pathway.

METHODS AND RESULTS

We observed the expression of HMGB1 and p-ATM in biopsies of esophageal cancer patients with immunohistochemical staining. Western blot and RT-qPCR were applied to detect the protein and RNA related to PI3K/Akt/ATM pathway, respectively. In addition, we inhibited the PI3K/Akt pathway with ly294002 and activated it with IGF1, then we explored the invasion, proliferation ability, and apoptosis of esophageal cancer cells in vitro by transwell, CCK8 assay, and flow cytometry respectively. In vivo, xenograft tumor model was established in nude mice to study the effect of HMGB1 on radioresistance via PI3K/AKT/ATM Signaling Pathway. The survival rate in patients with single positive/double negative expression of HMGB1 and p-ATM was significantly higher than in those with both positive expression of HMGB1 and p-ATM, the depletion of HMGB1 combined with ly294002 significantly inhibited cell proliferation and invasion ability, meanwhile, the addition of IGF1 reversed it. Meanwhile, depletion of HMGB1 and ly294002 promoted apoptosis and arrested the cancer cells in G0/G1 cell cycle with the decreased expression of Cyclin D1 and CDK4 and improved P16. We further validated these results in vivo, the application of HMGB1 silencing promoted apoptosis of xenograft tumors after radiation, especially combined with pathway inhibitor ly294002.

CONCLUSIONS

Esophageal cancer patients with high expression of HMGB1 and p-ATM have a poor prognosis after chemo-radiotherapy. Down-regulation of HMGB1 may promote the radio-sensitivity of esophageal cancer cells through regulating PI3K/Akt/ATM pathway.

Circ-DONSON Knockdown Inhibits Cell Proliferation and Radioresistance of Breast Cancer Cells via Regulating SOX4

Background

Circular RNAs have been validated as critical regulators in the development of breast cancer (BC). Circ-DONSON is involved in the progression of glioma and gastric cancer. However, the biological role of circ-DONSON in BC remains unclear, and the aim of this study was to explore the biological role of circ-DONSON in BC.

Methods

Human tissue samples and BC cell lines were collected in this study. siRNAs against circ-DONSON were transfected into BC cell lines for silencing of circ-DONSON. Quantitative real-time PCR was used to test the circ-DONSON expression. Cell counting kit-8 (CCK-8), 5-bromo-2' deoxyuridine enzyme-linked immunosorbent assay (BrdU-ELISA), colony formation, and caspase-3 activity assays were used to assess cell proliferation, cell survival, and cell viability. Western blotting analysis was used to detect the protein expression levels.

Results

Our findings showed that circ-DONSON showed high expression in BC tissues and cell lines. CCK-8 and BrdU-ELISA assays showed that circ-DONSON knockdown inhibited BC cell proliferation. Moreover, cell survival, cell viability, and caspase-3 activity assays showed that circ-DONSON knockdown reduced the radioresistance of BC cells. Mechanistically, circ-DONSON regulated BC cell proliferation and radioresistance via SRY-box transcription factor 4 (SOX4). SOX4 overexpression significantly rescued the effect of circ-DONSON knockdown on BC cell proliferation and radioresistance. Moreover, circ-DONSON activated the Wnt/β-catenin pathway in BC cells via SOX4.

Conclusion

Our study concluded that circ-DONSON knockdown hindered cell proliferation and radioresistance through the SOX4/Wnt/β-catenin pathway in BC.

Crosstalk between circRNAs and the PI3K/AKT signaling pathway in cancer progression

Circular RNAs (circRNAs), covalently closed noncoding RNAs, are widely expressed in eukaryotes and viruses. They can function by regulating target gene expression, linear RNA transcription and protein generation. The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway plays key roles in many biological and cellular processes, such as cell proliferation, growth, invasion, migration, and angiogenesis. It also plays a pivotal role in cancer progression. Emerging data suggest that the circRNA/PI3K/AKT axis modulates the expression of cancer-associated genes and thus regulates tumor progression. Aberrant regulation of the expression of circRNAs in the circRNA/PI3K/AKT axis is significantly associated with clinicopathological characteristics and plays an important role in the regulation of biological functions. In this review, we summarized the expression and biological functions of PI3K-AKT-related circRNAs in vitro and in vivo and assessed their associations with clinicopathological characteristics. We also further discussed the important role of circRNAs in the diagnosis, prognostication, and treatment of cancers.

Circular RNA circ-ERBB2 promotes HER2-positive breast cancer progression and metastasis via sponging miR-136-5p and miR-198

Background

Circular RNAs (circRNAs) are pivotal regulators of various human cancers and circ-ERBB2 is abnormally expressed in breast cancer cells. However, the role and mechanism of circ-ERBB2 in HER2-positive breast cancer are still unknown.

Methods

The circ-ERBB2 expressions in the tumor tissues of HER2-positive breast cancer patients were tested using quantitative real-time PCR. The circ-ERBB2 function was investigated by cell counting kit 8 assay, Transwell, flow cytometry and Western blot. Mechanistically, fluorescence in situ hybridization, RNA immunoprecipitation, RNA pull-down and dual-luciferase reporter gene assays were conducted to confirm the interaction between circ-ERBB2 and miR-136-5p or miR-198 in HER2-positive breast cancer cells.

Results

Circ-ERBB2 was elevated in the tumor tissues of HER2-positive breast cancer patients. Functionally, the interference with circ-ERBB2 repressed HER2-positive breast cancer cell proliferation, migration, invasion and accelerated cell apoptosis. Furthermore, the mechanistic analysis corroborated that circ-ERBB2 acted as a competing endogenous RNA for miR-136-5p or miR-198 to relieve the repressive influence of miR-136-5p or miR-198 on its target transcription factor activator protein 2C (TFAP2C). Meanwhile, in vivo assays further corroborated the oncogenic function of circ-ERBB2 in HER2-positive breast cancer.

Conclusions

Circ-ERBB2 accelerated HER2-positive breast cancer progression through the circ-ERBB2/miR-136-5p/TFAP2C axis or the circ-ERBB2/miR-198/TFAP2C axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03114-8.

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.

Classification of NF1 microdeletions and its importance for establishing genotype/phenotype correlations in patients with NF1 microdeletions

An estimated 5–11% of patients with neurofibromatosis type-1 (NF1) harbour large deletions encompassing the NF1 gene and flanking regions. These NF1 microdeletions are subclassified into type 1, 2, 3 and atypical deletions which are distinguishable from each other by their extent and by the number of genes included within the deletion regions as well as the frequency of mosaicism with normal cells. Most common are type-1 NF1 deletions which encompass 1.4-Mb and 14 protein-coding genes. Type-1 deletions are frequently associated with overgrowth, global developmental delay, cognitive disability and dysmorphic facial features which are uncommon in patients with intragenic pathogenic NF1 gene variants. Further, patients with type-1 NF1 deletions frequently exhibit high numbers of neurofibromas and have an increased risk of malignant peripheral nerve sheath tumours. Genes located within the type-1 NF1 microdeletion interval and co-deleted with NF1 are likely to act as modifiers responsible for the severe disease phenotype in patients with NF1 microdeletions, thereby causing the NF1 microdeletion syndrome. Genotype/phenotype correlations in patients with NF1 microdeletions of different lengths are important to identify such modifier genes. However, these correlations are critically dependent upon the accurate characterization of the deletions in terms of their extent. In this review, we outline the utility as well as the shortcomings of multiplex ligation-dependent probe amplification (MLPA) to classify the different types of NF1 microdeletion and indicate the importance of high-resolution microarray analysis for correct classification, a necessary precondition to identify those genes responsible for the NF1 microdeletion syndrome.

Exosome-mediated transfer of circHIPK3 promotes trastuzumab chemoresistance in breast cancer

Breast cancer (BC) remains a public health dilemma in the world and it is one of the leading causes of death among women. Trastuzumab is a kind of commonly-used drugs in the treatment of BC, which especially can provide substantial benefits for HER2-positive BC. However, its long-time usage results in the emergence of resistance, which cuts down its efficacy in BC and leads to a poorer overall survival rate. Hence, the attempt of this study was to investigate how the drug resistance was enhanced. It has been identified that circHIPK3 could act as an oncogene in BC and promoted cell development through and a series of function assays. However, the underlying regulatory mechanism of circHIPK3 is not well established in trastuzumab resistance to date. Furthermore, we found the functional role of exosomes in trastuzumab chemoresistance and discovered that exosomes derived from trastuzumab-resistant cells could enhance the drug resistance of trastuzumab-sensitive cells. In last decades, competing endogenous RNA (ceRNA) has been a hot topic to investigate potential mechanism in cells. We subsequently performed mechanism experiments and rescue assays to verify circHIPK3 acted as a ceRNA in BC cells. In conclusion, we uncovered the regulatory mechanism by which exosome-transmitted circHIPK3 could promote trastuzumab chemoresistance of drug-sensitive BC cells.

CircRPPH1 serves as a sponge for miR-296-5p to enhance progression of breast cancer by regulating FOXP4 expression

Circular RNAs (circRNAs) have been demonstrated to play critical roles in the initiation and development of breast cancer (BC). This study aimed to uncover the regulatory roles of a novel circRNA, circRPPH1 (hsa_circ_0000514) in BC progression. CircRPPH1, miR-296-5p and FOXP4 levels were determined by qRT-PCR. CircRPPH1 stability was detected in response to ribonuclease (RNase) R digestion and actinomycin D treatment. Cell growth, migration and invasion were evaluated using various functional experiments. Protein levels of proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 9 (MMP-9), hexokinase 2 (HK2) and forkhead box protein 4 (FOXP4) were measured by Western blotting. Metabolic alterations of BC cells were evaluated using commercial kits. The interaction between miR-296-5p and circRPPH1/FOXP4 was assessed using dual-luciferase assay, RNA pull-down, and RNA immunoprecipitation (RIP) assay. The in vivo tumorigenesis was assessed in nude mice. According to the results, up-regulation of circRPPH1 was closely correlated with the poor prognosis of BC patients. Functional experiments showed that knockdown of circRPPH1 repressed BC cell growth, migration, invasion, glycolysis, and in vivo tumor growth. In addition, circRPPH1 could sponge miR-296-5p to enhance FOXP4 expression in BC cells. miR-296-5p inhibition or FOXP4 overexpression restored the malignant properties of circRPPH1-silenced BC cells. Thus, circRPPH1 promoted BC malignant progression through regulating miR-296-5p/FOXP4 axis, indicating a possible novel therapeutic strategy involving circRNA for BC patients.

Silencing of circHIPK3 Sensitizes Paclitaxel-Resistant Breast Cancer Cells to Chemotherapy by Regulating HK2 Through Targeting miR-1286

Background

Resistance development to paclitaxel (PTX) has become a major obstacle in the successful treatment of breast cancer (BC). Circular RNAs (circRNAs) have been identified as essential regulators in PTX resistance of BC. Here, we explored the precise roles of circRNA homeodomain interacting protein kinase 3 (circHIPK3, circ_0000284) in PTX resistance of BC.

Methods

The expression levels of circHIPK3, microRNA (miR)-1286, and hexokinase 2 (HK2) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Ribonuclease R (RNase R) assay was used to confirm the stability of circHIPK3. Cellular localization of circHIPK3 was assessed by subcellular localization assay. The half maximal inhibitory concentration (IC₅₀) value for PTX was measured by Cell Counting Kit-8 (CCK-8) assay. Cell colony formation, cell cycle distribution, and apoptosis were gauged by colony formation assay and flow cytometry, respectively. Animal studies were performed to evaluate the role of circHIPK3 in vivo. The direct relationship between miR-1286 and circHIPK3 or HK2 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

Results

Our results showed that circHIPK3 was up-regulated in PTX-resistant BC tissues and cells compared with the sensitive counterparts. The silencing of circHIPK3 promoted PTX sensitivity of PTX-resistant BC cells in vitro and in vivo. CircHIPK3 directly targeted miR-1286, and miR-1286 acted as a downstream mediator of circHIPK3 function in vitro. HK2 was a direct target of miR-1286, and circHIPK3 modulated HK2 expression through miR-1286. The increased expression of miR-1286 sensitized PTX-resistant BC cells to PTX in vitro by down-regulating HK2.

Conclusion

Our findings demonstrated that the silencing of circHIPK3 sensitized PTX-resistant BC cells to PTX therapy at least in part via the regulation of the miR-1286/HK2 axis.

The Regulation Network and Clinical Significance of Circular RNAs in Breast Cancer

Breast cancer is one of the most common malignant tumors in women worldwide. Circular RNA (circRNA) is a class of structurally stable non-coding RNA with a covalently closed circular structure. In recent years, with the development of high-throughput RNA sequencing, many circRNAs have been discovered and have proven to be clinically significant in the development and progression of breast cancer. Importantly, several regulators of circRNA biogenesis have been discovered. Here, we systematically summarize recent progress regarding the network of regulation governing the biogenesis, degradation, and distribution of circRNAs, and we comprehensively analyze the functions, mechanisms, and clinical significance of circRNA in breast cancer.

circVAPA promotes the proliferation, migration and invasion of oral cancer cells through the miR-132/HOXA7 axis

Objective

To study the relationship between the circular RNA vesicle-associated membrane protein-associated protein A (circVAPA) and the pathogenesis of oral squamous cell carcinoma.

Methods

The expression of circVAPA was detected by RT-qPCR. In vitro loss-of-function experiments were performed in Cal-27 cells. The malignant phenotype of cells was evaluated by cell counting kit-8, clone formation and transwell assays. Luciferase reporter assays were used to assess the circVAPA/miR-132/homeobox A (HOXA) regulatory axis.

Results

circVAPA expression was significantly increased in oral cancer tissues and cells. The overall survival and progression-free survival of patients with oral cancer who exhibited high circVAPA expression were significantly shorter compared with those with low expression. circVAPA expression was closely related to tumor size, TNM stage and distant metastasis. circVAPA knockdown reduced the proliferation, invasion and migration of Cal-27 cells. MiR-132 was identified as a target of circVAPA in Cal-27 cells. Cotransfection with si-circVAPA and miR-132 inhibitor reversed the inhibitory effect of circVAPA knockdown on cell malignant phenotypes. HOXA7 was further identified as a downstream target of miR-132.

Conclusion

circVAPA is highly expressed in oral cancer, and its abnormal expression might affect the proliferation, invasion and migration of oral cancer cells by modulating the miR-132/HOXA7 signaling axis.

circHIPK3 (hsa_circ_0000284) Promotes Proliferation, Migration and Invasion of Breast Cancer Cells via miR-326

Purpose

circHIPK3 has carcinogenic or anti-tumor effects on different cancers. However, there is no relevant research showing whether circHIPK3 was involved in breast cancer (BCa). In this research, the aim was to analyze the function and possible molecular mechanism of circHIPK3 in BCa.

Methods

The expression of circHIPK3 in human BCa tissues and cells was detected by real-time quantitative PCR (RT-qPCR). CircInteractome and dual-luciferase assays were performed to detect circRNA-miRNA targeting relationship. Ribonuclease R treatment, RT-qPCR, Western blot and immunohistochemistry were performed to determine the stability, expressions, abundance of target genes. Loss-of-function or gain-of-function experiments were used to analyze the effects of circHIPK3 and miR-326 on BCa in vivo and in vitro. In vitro, MCF7 and BT20 cells were transfected with circHIPK3 or sicircHIPK3 or miR-326 mimic; in vivo, female BALB/c mice were subcutaneously injected with MCF7 cells (transfected with CirchipK3 or miR-326 mimic) to establish xenograft models.

Results

The circular structure of circHIPK3 was abundantly expressed in the cytoplasm and was up-regulated in BCa. Silenced circHIPK3 suppressed malignant phenotype of BCa cells. MiR-326 interacted with circHIPK3 and the two were negatively correlated. Overexpressed circHIPK3 promoted cell viability, proliferation, migration and invasion, but inhibited apoptosis. Moreover, overexpressed circHIPK3 promoted the expressions of EMT-related genes and antiapoptotic genes, but inhibited proapoptotic gene expressions. Overexpressed circHIPK3 promoted tumor growth and Ki-67 levels, inhibited apoptosis in vivo. The above mentioned effects of circHIPK3 were reversed by miR-326 in vitro or in vivo.

Conclusion

circHIPK3 promoted proliferation, migration and invasion of BCa cells through regulating miR-326.

Biogenesis, cellular effects, and biomarker value of circHIPK3

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

Non-coding RNA in cancer

Majority of the human genome is transcribed to RNAs that do not encode proteins. These non-coding RNAs (ncRNAs) play crucial roles in regulating the initiation and progression of various cancers. Given the importance of the ncRNAs, the roles of ncRNAs in cancers have been reviewed elsewhere. Thus, in this review, we mainly focus on the recent studies of the function, regulatory mechanism and therapeutic potential of the ncRNAs including microRNA (miRNA), long ncRNA (lncRNA), circular RNA (circRNA) and PIWI interacting RNA (piRNA), in different type of cancers.

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

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

Non-Coding RNAs in Cancer Diagnosis and Therapy: Focus on Lung Cancer

Over the last several decades, clinical evaluation and treatment of lung cancers have largely improved with the classification of genetic drivers of the disease, such as EGFR, ALK, and ROS1. There are numerous regulatory factors that exert cellular control over key oncogenic pathways involved in lung cancers. In particular, non-coding RNAs (ncRNAs) have a diversity of regulatory roles in lung cancers such that they have been shown to be involved in inducing proliferation, suppressing apoptotic pathways, increasing metastatic potential of cancer cells, and acquiring drug resistance. The dysregulation of various ncRNAs in human cancers has prompted preclinical studies examining the therapeutic potential of restoring and/or inhibiting these ncRNAs. Furthermore, ncRNAs demonstrate tissue-specific expression in addition to high stability within biological fluids. This makes them excellent candidates as cancer biomarkers. This review aims to discuss the relevance of ncRNAs in cancer pathology, diagnosis, and therapy, with a focus on lung cancer.

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

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