Upregulation of hsa_circ_0136666 contributes to breast cancer progression by sponging miR-1299 and targeting CDK6

The crosstalk between non-coding RNAs and cell-cycle events: A new frontier in cancer therapy

The cell cycle comprises sequential events during which a cell duplicates its genome and divides it into two daughter cells. This process is tightly regulated to ensure that the daughter cell receives identical copied chromosomal DNA and that any errors in the DNA during replication are correctly repaired. Cyclins and their enzyme partners, cyclin-dependent kinases (CDKs), are critical regulators of G- to M-phase transitions during the cell cycle. Mitogenic signals induce the formation of the cyclin/CDK complexes, resulting in phosphorylation and activation of the CDKs. Once activated, cyclin/CDK complexes phosphorylate specific substrates that drive the cell cycle forward. The sequential activation and inactivation of cyclin-CDK complexes are tightly controlled by activating and inactivating phosphorylation events induced by cell-cycle proteins. The non-coding RNAs (ncRNAs), which do not code for proteins, regulate cell-cycle proteins at the transcriptional and translational levels, thereby controlling their expression at different cell-cycle phases. Deregulation of ncRNAs can cause abnormal expression patterns of cell-cycle-regulating proteins, resulting in abnormalities in cell-cycle regulation and cancer development. This review explores how ncRNA dysregulation can disrupt cell division balance and discusses potential therapeutic approaches targeting these ncRNAs to control cell-cycle events in cancer treatment.

Synergistic Immunoregulation: harnessing CircRNAs and PiRNAs to Amplify PD-1/PD-L1 Inhibition Therapy

The utilization of PD-1/PD-L1 inhibitors marks a significant advancement in cancer therapy. However, the efficacy of monotherapy is still disappointing in a substantial subset of patients, necessitating the exploration of combinational strategies. Emerging from the promising results of the KEYNOTE-942 trial, RNA-based therapies, particularly circRNAs and piRNAs, have distinguished themselves as innovative sensitizers to immune checkpoint inhibitors (ICIs). These non-coding RNAs, notable for their stability and specificity, were once underrecognized but are now known for their crucial roles in regulating PD-L1 expression and bolstering anti-cancer immunity. Our manuscript offers a comprehensive analysis of selected circRNAs and piRNAs, elucidating their immunomodulatory effects and mechanisms, thus underscoring their potential as ICIs enhancers. In conjunction with the recent Nobel Prize-awarded advancements in mRNA vaccine technology, our review highlights the transformative implications of these findings for cancer treatment. We also discuss the prospects of circRNAs and piRNAs in future therapeutic applications and research. This study pioneers the synergistic application of circRNAs and piRNAs as novel sensitizers to augment PD-1/PD-L1 inhibition therapy, demonstrating their unique roles in regulating PD-L1 expression and modulating immune responses. Our findings offer a groundbreaking approach for enhancing the efficacy of cancer immunotherapy, opening new avenues for treatment strategies. This abstract aims to encapsulate the essence of our research and the burgeoning role of these non-coding RNAs in enhancing PD-1/PD-L1 inhibition therapy, encouraging further investigation into this promising field.

Hsa_circ_0136666 mediates the antitumor effect of curcumin in colorectal carcinoma by regulating CXCL1 via miR-1301-3p

BACKGROUND

This study investigate the anti-tumor effect of curcumin and whether its mediated by hsa_circ_0136666 through miR-1301-3p/CXCL1 in colorectal carcinoma (CRC). Through multiple experiments, we have drawn the conclusion that curcumin inhibited CRC development through the hsa_circ_0136666/miR-1301-3p/CXCL1 axis, hinting at a novel treatment option for curcumin to prevent CRC development.

AIM

To determine whether hsa_circ_0136666 involvement in curcumin-triggered CRC progression was mediated by sponging miR-1301-3p.

METHODS

Cell counting kit-8, colony-forming cell, 5-ethynyl-2'-deoxyuridine, and flow cytometry assays were carried out to determine cell proliferation, apoptosis, and cell cycle progression. Real-time quantitative polymerase chain reaction quantified hsa_circ_0136666, miR-1301-3p, and chemokine (C-X-C motif) ligand 1 (CXCL1), and western blot analysis determined CXCL1, B-cell lymphoma-2 (Bcl-2), and Bcl-2 related X protein (Bax) protein levels. CircBank or starbase software was first used for the prediction of miR-1301-3p binding with hsa_circ_0136666 and CXCL1, followed by RNA pull-down, RNA immunoprecipitation, and dual-luciferase reporter assay validation. In vivo experiments were implemented in a murine xenograft model.

RESULTS

Curcumin blocked CRC cell proliferation but boosted apoptosis. Moreover, elevated hsa_circ_0136666 Levels were observed in CRC cells, which were reduced by curcumin. In vitro, hsa_circ_0136666 overexpression abolished the antitumor activity of CRC cells. Mechanical analysis revealed the ability of hsa_circ_0136666 to sponge miR-1301-3p to modulate CXCL1 levels.

CONCLUSION

Curcumin inhibited CRC development through the hsa_circ_0136666/miR-1301-3p/CXCL1 axis, hinting at a novel treatment option for curcumin to prevent CRC development.

Circulating miRNAs signature on breast cancer: the MCC-Spain project

PURPOSE

To build models combining circulating microRNAs (miRNAs) able to identify women with breast cancer as well as different types of breast cancer, when comparing with controls without breast cancer.

METHOD

miRNAs analysis was performed in two phases: screening phase, with a total n = 40 (10 controls and 30 BC cases) analyzed by Next Generation Sequencing, and validation phase, which included 131 controls and 269 cases. For this second phase, the miRNAs were selected combining the screening phase results and a revision of the literature. They were quantified using RT-PCR. Models were built using logistic regression with LASSO penalization.

RESULTS

The model for all cases included seven miRNAs (miR-423-3p, miR-139-5p, miR-324-5p, miR-1299, miR-101-3p, miR-186-5p and miR-29a-3p); which had an area under the ROC curve of 0.73. The model for cases diagnosed via screening only took in one miRNA (miR-101-3p); the area under the ROC curve was 0.63. The model for disease-free cases in the follow-up had five miRNAs (miR-101-3p, miR-186-5p, miR-423-3p, miR-142-3p and miR-1299) and the area under the ROC curve was 0.73. Finally, the model for cases with active disease in the follow-up contained six miRNAs (miR-101-3p, miR-423-3p, miR-139-5p, miR-1307-3p, miR-331-3p and miR-21-3p) and its area under the ROC curve was 0.82.

CONCLUSION

We present four models involving eleven miRNAs to differentiate healthy controls from different types of BC cases. Our models scarcely overlap with those previously reported.

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

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

Hsa_circ_0001925 promotes malignant progression in triple-negative breast cancer via miR-1299/YY1 axis

BACKGROUND

Circular RNAs (circRNAs) are related to the pathogenesis and progression of triple-negative breast cancer (TNBC). The aim of this study was to investigate the role and mechanism of hsa_circ_0001925 in TNBC progression.

METHODS

Hsa_circ_0001925, microRNA (miR)-1299 and Yin Yang 1 (YY1) levels were examined in TNBC via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry, wound healing assay and tube formation assay were conducted to estimate the effects of hsa_circ_0001925 on malignant phenotypes of TNBC tumors. Several protein levels were measured with western blot. The regulatory relationship between miR-1299 and hsa_circ_0001925 or YY1 was validated using a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft assay was used to estimate the effect of hsa_circ_0001925 in TNBC in vivo.

RESULTS

Hsa_circ_0001925 and YY1 levels were upregulated, while miR-1299 abundance was downregulated in TNBC tissues and cells. Hsa_circ_0001925 silencing constrained cell proliferation, migration and angiogenesis whereas it promoted apoptosis in vitro, and hsa_circ_0001925 silencing significantly curbed xenograft tumor growth in vivo. Hsa_circ_0001925 acted as a miRNA sponge for miR-1299. Hsa_circ_0001925 decreased YY1 expression by sponging miR-1299. MiR-1299 downregulation alleviated the effects of hsa_circ_0001925 knockdown on BC progression. MiR-1299 interacted with the 3' untranslated region (3' UTR) of YY1, and YY1 overexpression partly reversed the effects of miR-1299 overexpression on BC progression.

CONCLUSION

Our findings showed that hsa_circ_0001925 mediated TNBC progression via regulating miR-1299/YY1 axis, providing a potential target for BC treatment.

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.

Tanshinone IIA (TSIIA) represses the progression of non-small cell lung cancer by the circ_0020123/miR-1299/HMGB3 pathway

Tanshinone IIA (TSIIA), a multi-pharmaceutical compound, has been demonstrated to have anti-tumor properties. This study explores the potential regulatory mechanism of TSIIA on non-small cell lung cancer (NSCLC) progression. The cytotoxicity of TSIIA was evaluated by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) and LDH (lactate dehydrogenase) assays. Expression levels of circ_0020123 (hsa_circ_0020123) and microRNA-1299 (miR-1299) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, migration, invasion, and apoptosis were analyzed by MTT, colony formation, transwell, wound-healing, or flow cytometry assays. The relationship between miR-1299 and circ_0020123 or HMGB3 (high mobility group box 3) was verified by the dual-luciferase reporter and/or RNA immunoprecipitation (RIP) assays. Protein level of HMGB3 was measured by western blotting. The relationship between TSIIA and circ_0020123 was confirmed by xenograft assay. TSIIA reduced xenograft tumor growth in vivo and repressed proliferation, migration, invasion, and facilitated apoptosis of NSCLC cells in vitro. TSIIA reduced circ_0020123 and HMGB3 expression, whereas elevated miR-1299 expression in NSCLC cells. Circ_0020123 knockdown enhanced the repressive influence of TSIIA treatment on the malignancy of NSCLC cells in vitro and in vivo. Circ_0020123 sponged miR-1299 to regulate HMGB3 expression under TSIIA treatment. MiR-1299 inhibitor reversed circ_0020123 knockdown-mediated influence on malignant behaviors of NSCLC cells under TSIIA treatment. HMGB3 elevation offset the suppressive impact of miR-1299 mimic on the malignancy of NSCLC cells under TSIIA treatment. TSIIA curbed NSCLC progression by the circ_0020123/miR-1299/HMGB3 axis, manifesting that the TSIIA/circ_0020123/miR-1299/HMG regulatory network might be a potential treatment strategy for NSCLC.

The pivotal regulatory factor circBRWD1 inhibits arsenic exposure-induced lung cancer occurrence by binding mRNA and regulating its stability

Multiple studies have indicated that circular RNAs (circRNAs) play a regulatory role in different stages of tumors by interacting with various molecules. With continuous in-depth research on the biological functions of circRNAs, increasing evidence has shown that circRNAs play important roles in carcinogenesis caused by environmental pollutants. However, the function and mechanism of circRNAs in arsenic exposure-induced lung cancer occurrence have not been reported. In this study, RNA sequencing and qPCR assays revealed that the expression of circBRWD1 was decreased in BEAS-2B-As cells and multiple lung cancer cell lines. Silencing circBRWD1 promoted cell viability and proliferation, inhibited cell apoptosis, and accelerated the G0/G1 phase transition in BEAS-2B-As cells; however, these functions were abrogated by circBRWD1 overexpression. Mechanistically, under arsenic exposure, expression of decreased circBRWD1 led to enhanced stability of the mRNA to which it directly binds (c-JUN, c-MYC, and CDK6 mRNA), increasing its expression. This mechanism promotes the malignant transformation of lung cells and ultimately leads to lung cancer. Our findings thus reveal the molecular mechanism of arsenic carcinogenesis.

Circ_0136666 aggravates osteosarcoma development through mediating miR-1244/CEP55 axis

Background

Accumulating articles demonstrate that circular RNAs play pivotal functions in tumorigenesis. However, the working mechanism of circ_0136666 in osteosarcoma (OS) progression remains to be further clarified.

Methods

Real time-quantitative polymerase chain reaction and western blot assay were applied to determine RNA and protein expression, respectively. Cell proliferation was assessed by 5-Ethynyl-2′-deoxyuridine assay and colony formation assay. Transwell assays were carried out to assess cell migration and invasion abilities. Flow cytometry was performed to analyze cell apoptosis. Cell glycolysis was evaluated by analyzing the uptake of glucose and the production of lactate using the corresponding kits. Dual-luciferase reporter assay and biotinylated RNA-pull down assay were performed to confirm the target interaction between microRNA-1244 (miR-1244) and circ_0136666 or centrosomal protein 55 (CEP55). Xenograft tumor model was utilized to explore the role of circ_0136666 in tumor growth in vivo.

Results

Circ_0136666 expression was prominently elevated in OS tissues and cell lines. Circ_0136666 absence restrained the proliferation, migration, invasion and glycolytic metabolism and promoted the apoptosis of OS cells. Circ_0136666 negatively regulated miR-1244 expression by binding to it in OS cells. MiR-1244 overexpression suppressed the malignant behaviors of OS cells. CEP55 was a target of miR-1244 in OS cells. Circ_0136666 positively regulated CEP55 expression partly by sequestering miR-1244 in OS cells. CEP55 overexpression largely reversed circ_0136666 silencing-mediated influences in OS cells. Circ_0136666 silencing significantly suppressed tumor growth in vivo.

Conclusion

Circ_0136666 silencing inhibited OS progression partly by targeting miR-1244/CEP55 signaling. Silencing circ_0136666 and CEP55 or restoring miR-1244 level might be a potential therapeutic strategy for OS.

Circ_0001955 plays a carcinogenic role in breast cancer via positively regulating GLUT1 via decoying miR-1299

BACKGROUND

Breast cancer is widespread in females. The role of circular RNA (circRNA) in breast cancer has aroused much attention. However, the function of several circRNAs remain unclear. The aim of our study was to determine the role of circ_0001955 in breast cancer.

METHODS

Quantitative real-time PCR (qPCR) and western blot was employed for expression analysis of circ_0001955, miR-1299 and glucose transporter 1 (GLUT1). Cell functions including proliferation, apoptosis, migration, invasion and angiogenesis, were assessed using EdU, flow cytometry, transwell and tube formation assays. Glycolysis metabolism was assessed according to glucose consumption, lactate production and ATP content. Dual-luciferase reporter assay and RIP assay were utilized to validate the binding between miR-1299 and circ_0001955 or GLUT1. The effects of circ_0001955 in vivo were observed by animal study.

RESULTS

Upregulation of circ_0001955 was detected in breast cancer. Knockdown of circ_0001955 inhibited breast cancer cell proliferation, migration, invasion, angiogenesis and glycolysis. MiR-1299 was a target of circ_0001955, and its repression reversed the effects of circ_0001955 knockdown. Moreover, circ_0001955 targeted miR-1299 to positively regulate GLUT1 expression. GLUT1 overexpression reversed the effects of miR-1299 enrichment. GLUT1 knockdown was verified to block tumor growth in vivo.

CONCLUSIONS

Circ_0001955 was found to promote breast cancer malignant development via targeting of the miR-1299/GLUT1 pathway, which contributes to our understanding of the pathogenesis of breast cancer.

CircARL8B Contributes to the Development of Breast Cancer Via Regulating miR-653-5p/HMGA2 Axis

Circular RNAs (circRNAs) act as essential regulators in breast cancer (BC) progression. In this paper, we aimed to investigate the functions of circARL8B in BC. The levels of circARL8B, ADP Ribosylation Factor Like GTPase 8B (ARL8B), miR-653-5p and high-mobility group AT-hook 2 (HMGA2) mRNA were examined by qRT-PCR. The stability of circARL8B was determined by RNase R assay and Actinomycin D assay. Cell viability and metastasis were evaluated by Cell Counting Kit-8 (CCK-8) assay and transwell assay, respectively. The levels of cellular phospholipids and triglycerides were measured using relevant kits. Protein levels were measured by western blot analysis. The association between miR-653-5p and circARL8B or HMGA2 was verified by dual-luciferase reporter assay. A murine xenograft model was established to explore the function of circARL8B in vivo. CircARL8B was increased in BC tissues and cells. CircARL8B silencing inhibited cell viability, migration, invasion and fatty acid metabolism in BC cells in vitro and blocked tumor growth in vivo. MiR-653-5p was identified as the target of circARL8B and miR-653-5p was negatively modulated by circARL8B. The suppressive role of circARL8B silencing in BC cell progression was abolished by miR-653-5p downregulation. Moreover, HMGA2 was the target gene of miR-653-5p. HMGA2 overexpression abrogated the effect of miR-653-5p on BC cell development. In addition, circARL8B knockdown might block PGE2/PI3K/AKT/GSK-3β/Wnt/β-catenin pathway. Silencing of circARL8B inhibited cell viability, migration, invasion and fatty acid metabolism via miR-653-5p/HMGA2 axis in BC.

Dissecting the Role of Circular RNAs in Sarcomas with Emphasis on Osteosarcomas

Circular RNAs (circRNAs) are single-stranded RNAs generated from exons back-splicing from a single pre-mRNA, forming covalently closed loop structures which lack 5'-3'-polarity or polyadenylated tail. Ongoing research depicts that circRNAs play a pivotal role in tumorigenesis, tumor progression, metastatic potential and chemoresistance by regulating transcription, microRNA (miRNA) sponging, RNA-binding protein interactions, alternative splicing and to a lesser degree, protein coding. Sarcomas are rare malignant tumors stemming from mesenchymal cells. Due to their clinically insidious onset, they often present at advanced stage and their treatment may require aggressive chemotherapeutic or surgical options. This review is mainly focused on the regulatory functions of circRNAs on osteosarcoma progression and their potential role as biomarkers, an area which has prompted lately extensive research. The attributed oncogenic role of circRNAs on other mesenchymal tumors such as Kaposi Sarcoma (KS), Rhabdomyosarcoma (RMS) or Gastrointestinal Stromal Tumors (GISTs) is also described. The involvement of circRNAs on sarcoma oncogenesis and relevant emerging diagnostic, prognostic and therapeutic applications are expected to gain more research interest in the future.

Circular RNAs in cell cycle regulation: Mechanisms to clinical significance

Circular RNAs (circRNAs), a type of non‐coding RNA, are single‐stranded circularized molecules characterized by high abundance, evolutionary conservation and cell development‐ and tissue‐specific expression. A large body of studies has found that circRNAs exert a wide variety of functions in diverse biological processes, including cell cycle. The cell cycle is controlled by the coordinated activation and deactivation of cell cycle regulators. CircRNAs exert mutifunctional roles by regulating gene expression via various mechanisms. However, the functional relevance of circRNAs and cell cycle regulation largely remains to be elucidated. Herein, we briefly describe the biogenesis and mechanistic models of circRNAs and summarize their functions and mechanisms in the regulation of critical cell cycle modulators, including cyclins, cyclin‐dependent kinases and cyclin‐dependent kinase inhibitors. Moreover, we highlight the participation of circRNAs in cell cycle‐related signalling pathways and the clinical value of circRNAs as promising biomarkers or therapeutic targets in diseases related to cell cycle disorder.

Circular RNA circPRKDC promotes tumorigenesis of gastric cancer via modulating insulin receptor substrate 2 (IRS2) and mediating microRNA-493-5p

CircPRKDC has been disclosed to participate in the tumorigenesis of serval tumors, but the regulatory mechanisms of circPRKDC in GC are still unknown. CircPRKDC, miR-493-5p, and insulin receptor substrate 2 (IRS2) levels were tested by RT-qPCR. The epithelial-mesenchymal transition (EMT)-related protein levels were evaluated via western blot. The cell viability, migration and invasion were evaluated through CCK-8 and Transwell assays. Luciferase reporter and RIP assays were employed to confirm the binding ability between miR-493-5p and circPRKDC or IRS2. CircPRKDC was upregulated in GC samples, and circPRKDC silencing restrained GC cell viability, metastasis, and EMT and suppressed GC tumor growth. Besides, miR-493-5p was a target of circPRKDC, and the repressive impact of circPRKDC knockdown on GC development was neutralized by miR-493-5p inhibition. Moreover, miR-493-5p targeted IRS2 and IRS2 addition rescued the effects of circPRKDC depletion on GC progression. Finally, circPRKDC knockdown could regulate IRS2 expression by targeting miR-493-5p. These results elaborated that circPRKDC accelerated GC development via sponging miR-493-5p and increasing IRS2, which might provide novel potential targets for GC treatment.

circRNA-miRNA-mRNA in breast cancer

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

Circ_0008673 regulates breast cancer malignancy by miR-153-3p/CFL2 axis

BACKGROUND

Breast cancer is an aggressive tumor, which poses a heavy burden to human health. Circular RNAs have been involved in the pathogenesis of breast cancer. This study aims to investigate whether circ_0008673 mediates breast cancer malignant progression by microRNA-153-3p (miR-153-3p)/cofilin 2 (CFL2) pathway.

METHODS

The RNA levels of circ_0008673, miR-153-3p and CFL2 were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression of CFL2, E-cadherin and N-cadherin was determined by western blot analysis. Cell proliferation was demonstrated through cell counting kit-8 and cell colony-formation assays. Cell apoptosis was detected by flow cytometry analysis. Cell migratory and invasive capacities were determined by transwell assay. The associated relationship between miR-153-3p and circ_0008673 or CFL2 was predicted by online databases, and testified by dual-luciferase reporter and RNA immunoprecipitation assays. In vivo assay was employed to demonstrate the effects of circ_0008673 silencing on tumor formation in vivo.

RESULTS

Circ_0008673 and CFL2 expressions were upregulated, while miR-153-3p expression was downregulated in breast cancer tissues and cells compared with adjacent normal breast tissues and cells, respectively. Circ_0008673 overexpression promoted cell proliferation, migration and invasion, and repressed cell apoptosis, while circ_0008673 silencing had opposite effects. Additionally, circ_0008673 served as a sponge of miR-153-3p. And circ_0008673 was proved to regulate breast cancer cell malignancy by sponging miR-153-3p. MiR-153-3p was found to modulate breast cancer cell carcinogenesis via targeting CFL2. Furthermore, circ_0008673 silencing repressed tumor growth in vivo.

CONCLUSION

Circ_0008673 promoted breast cancer progression by upregulating CFL2 expression through sponging miR-153-3p. This study provides a theoretical basis for researching circRNA-directed treatment of breast cancer.

Hsa_circ_0136666 activates Treg-mediated immune escape of colorectal cancer via miR-497/PD-L1 pathway

PURPOSE

In the rankings of cancer mortality and incidence worldwide, colorectal cancer ranks fourth and the third, respectively. Circular RNA hsa_circ_0136666 (hsa_circ_0136666) is reported to participate in the growth of colorectal cancer. However, the mechanism by which hsa_circ_0136666 regulates the tumorigenesis of colorectal cancer needs to be further explored. In this study, we report here the role of hsa_circ_0136666 in the aberrant activation of Treg cells and immune evasion of tumor cells, providing a new strategy for the treatment of colorectal cancer.

METHODS

Western blotting assay and qRT-PCR assay were used to determine protein and mRNA expression levels. Dual-luciferase reporter assay was used to evaluate the targeted regulatory relationship. RNA immunoprecipitation was used to detect RNA binding. Colony formation assay was utilized to measure the cell proliferation. Flow cytometry was used to assess cell apoptosis. Xenograft model was setup to evaluate tumor growth.

RESULTS

The results showed that hsa_circ_0136666 and PD-L1 was increased in colorectal cancer cells while miR-497 was decreased in colorectal cancer cells when compared with normal colon epithelial cell line. Hsa_circ_0136666 was demonstrated to directly target miR-497, which also regulated PD-L1 by binding to its 3'UTR. Further mechanistic studies identified that hsa_circ_0136666 controlled cell proliferation and apoptosis via targeting miR-497 and regulating PD-L1 expression. Of note, hsa_circ_0136666 stimulated Treg cells mediated by miR-497/PD-L1 axis and its downstream signal pathway in Treg cells. Finally, hsa_circ_0136666 was found to accelerate the tumor growth in vivo.

CONCLUSIONS

Our findings demonstrated that hsa_circ_0136666 promoted the expression of PD-L1 by inhibiting miR-497 level in colorectal cancer, thus inducing the activation of Treg cells and leading to the immune escape of tumor, providing a novel mechanistic insight into the pathogenesis of colorectal cancer.

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.

Expression Profiles of Circular RNAs in Human Papillary Thyroid Carcinoma Based on RNA Deep Sequencing

Background

Papillary thyroid carcinoma (PTC) is the most prevalent type of thyroid cancer. Herein, we purposed to explore the expression patterns of circRNAs in PTC with the overarching goal of improving early diagnosis rates for individuals with PTC.

Methods

We used RNA deep sequencing to determine the expression patterns of circRNAs in PTC. Besides, RT-qPCR was employed to confirm circRNAs. The diagnostic potential of the circRNAs was explored by constructing ROC curves. GO along with KEGG pathway analyses were utilized to elucidate the potential biological roles of differentially expressed circRNAs. Moreover, we predicted cross talks among circRNAs, miRNAs, and mRNAs, followed by establishment of a ceRNA network.

Results

Deep sequencing of four PTC pairs and neighboring nontumor tissues identified 16569 circRNAs, of which, 301 were upregulated and 419 were downregulated. The RT-qPCR data demonstrated that the expression of chr5: 38481299-38530666-, chr2: 159932176-159945082-, chr10: 179994-249088+, chr3: 121378716-121381532+, and chr1: 237423092-237445522+ was downregulated, while the expression of chr4: 25665378-25667298+, chr5: 161330883-161336769-, chr1: 12578718-12579412-, chr7: 116695750-116700284+, and chr7: 116699071-116700284+ was upregulated. The stability test exhibited that circRNAs were more tolerant to temperature, RNase R, and time. On the other hand, ROC curves illustrated that chr4: 25665378-25667298+, chr1: 12578718-12579412-, chr7: 116699071-116700284+, chr7: 116695750-116700284+, chr5: 161330883-161336769-, and chr10: 179994-249088+ were effective as diagnostic indicators. However, a logistic regression model combining the six indicators achieved a better combined prediction index, with 97.7% sensitivity and 95.3% specificity. Moreover, GO along with KEGG pathway analyses illustrated that differentially expressed circRNAs were linked to tumorigenesis. Furthermore, bioinformatics analyses established a promising ceRNAs network among mRNAs, circRNAs, and miRNAs.

Conclusion

Herein, we demonstrated that several circRNAs are promising PTC diagnostic biomarkers. Further study on the functions and mechanisms of these circRNAs may contribute to the understanding of PTC.

Emerging role of circular RNAs in breast cancer

Circular RNAs (cirRNAs) are generally considered as non-coding RNAs which can act as molecular sponges for miRNAs, exert regulatory roles in transcription or splicing, and interplay with RNA binding proteins. These single-stranded transcripts can affect tumor growth, the metastatic ability of cancer cells, stemness properties, and resistance to therapeutic options. Recent investigations have shown the crucial effects of circrNAs in the evolution of breast cancer. Signature of circRNAs in breast cancer samples has been mostly assessed through microarray-based methods revealing up-regulation of some circRNAs such as circ-TFF1, circACAP2, circ-TFCP2L1, hsa_circ_0000519, circDENND4C, circPLK1 and circRNA_069718, while down-regulation of other circRNAs such as hsa_circ_0000375, circYap, hsa_circ_0025202, circTADA2A-E6, circASS1 and circRNA_BARD1 in breast cancer samples. Mechanistically, these transcripts mainly affect breast cancer tumorigenesis via serving as sponges for miRNAs. In the current manuscript, we explore the results of researches that appraised the role of circRNAs in breast cancer.

LINC00460 facilitated tongue squamous cell carcinoma progression via the miR-320b/IGF2BP3 axis

OBJECTIVE

We aimed to explore the role of long intergenic non-protein coding RNA 460 (LINC00460) in tongue squamous cell carcinoma (TSCC).

METHODS

We enrolled 27 TSCC patients to explore LINC00460 expression in clinical TSCC samples. RT-qPCR measured expression of molecules in this research. Loss-of-function assays explored biological function of LINC00460 in TSCC cells. RNA pull-down assay, luciferase reporter assay, and RIP assay investigated mechanism of LINC00460 underlying TSCC cells.

RESULTS

TSCC tissues and cell lines both showed high expression of LINC00460. Functionally, LINC00460 downregulation inhibited TSCC cell growth and promoted TSCC cell apoptosis. Additionally, LINC00460 silencing suppressed tumor growth in vivo. Mechanistically, LINC00460 bound with microRNA 320b (miR-320b) in TSCC cells. MiR-320b overexpression suppressed TSCC cell growth and promoted TSCC cell apoptosis. Moreover miR-320b targeted insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) 3'untranslated region in TSCC cells. Furthermore, IGF2BP3 silencing suppressed TSCC cell growth and promoted TSCC cell apoptosis. IGF2BP3 upregulation countervailed effects of silenced LINC00460 on TSCC cells. The LINC00460/miR-320b/IGF2BP3 axis was associated with lymph node metastasis of TSCC patients.

CONCLUSION

Our research illustrated that LINC00460 facilitated TSCC progression via the miR-320b/IGF2BP3 axis, highlighting a potential insight for the treatment of TSCC.

The role and underlying mechanism of miR-1299 in cancer

A type of evolutionarily conserved, noncoding, small, endogenous, single-stranded RNA, miRNAs are widely distributed in eukaryotes, where they participate in various biological processes as critical regulatory molecules. miR-1299 has mainly been investigated in cancers. miR-1299 is a tumor suppressor that regulates the expression of its target genes, activating or inhibiting the transcription of genes regulating biological activities including cell proliferation, migration, survival and programmed cell death. miR-1299 has become a hotspot in research of disease mechanisms and biomarkers; elucidation of the regulatory roles of miR-1299 in tumorigenesis, proliferation, apoptosis, invasion, migration and angiogenesis may provide a new perspective for understanding its biological functions as a tumor suppressor.

As key regulatory molecules, microRNAs participate in various biological processes and have become a widespread research focus. This article discusses how the microRNA miR-1299 plays a role as a tumor suppressor and participates in the regulation of tumor pathogenesis. We provide an overview of the role of miR-1299 in tumor diseases and discuss the pathogenesis and regulation mechanisms of miR-1299 in different specific cancers.

The depletion of Circ-PRKDC enhances autophagy and apoptosis in T-cell acute lymphoblastic leukemia via microRNA-653-5p/Reelin mediation of the PI3K/AKT/mTOR signaling pathway

A range of circular (Circ) RNAs have been demonstrated to be of therapeutic significance for the treatment of acute lymphoblastic leukemia (ALL). Here, we investigated the mechanisms underlying the action of Circ-PRKDC and the microRNA-653-5p/Reelin (miR-653-5p/RELN) axis in T-cell ALL (T-ALL).Clinical specimens were obtained from patients with T-ALL (n = 39) and healthy controls (n = 30). In each specimen, we determined the expression levels of Circ-PRKDC, miR-653-5p, and RELN. Human T-ALL cells (Jurkat) were transfected with Circ-PRKDC- or miR-653-5p-related sequences to investigate cell proliferation, apoptosis, and autophagy. We also determined the levels of Circ-PRKDC, miR-653-5p, RELN, and signaling proteins related to phosphoinositide 3-kinase (PI3K), AKT, and mammalian target of rapamycin (mTOR). Finally, we decoded the interactions between Circ-PRKDC, miR-653-5p, and RELN. The expression levels of Circ-PRKDC and RELN were upregulated in T-ALL tissues and cells while the levels of miR-653-5p were downregulated. Thereafter, then silencing of Circ-PRKDC, or the enforced expression of miR-653-5p, repressed the expression of RELN and the activation of the PI3K/AKT/mTOR signaling pathway, thus enhancing cell autophagy and apoptosis, and disrupting cell proliferation. Circ-PRKDC acted a sponge for miR-653-5p while miR-653-5p targeted RELN. The knockdown of miR-653-5p abrogated the silencing of Circ-PRKDC-induced effects in T-ALL cells. The depletion of Circ-PRKDC elevated miR-653-5p to silence RELN-mediated PI3K/AKT/mTOR signaling activation, thereby enhancing autophagy and apoptosis in T-ALL cells.

Circular RNA circ_SETD2 represses breast cancer progression via modulating the miR-155-5p/SCUBE2 axis

Breast cancer (BC) is the leading cause of cancer deaths in women worldwide. Circular RNA circ_SETD2 (circ_SETD2), also termed as hsa_circ_0065173, is reported to be abnormally expressed in BC. Nevertheless, the role and mechanism of circ_SETD2 in BC are unclear. Expression of circ_SETD2, miR-155-5p, and SCUBE2 mRNA was evaluated by quantitative real-time polymerase chain reaction. Cell cycle progression, proliferation, apoptosis, migration, and invasion were determined by flow cytometry, MTT, and transwell assays. The relationship between circ_SETD2 or SCUBE2 and miR-155-5p was verified through a dual-luciferase reporter assay. The role of circ_SETD2 in BC in vivo was confirmed by a xenograft assay. circ_SETD2 and SCUBE2 were downregulated, while miR-155-5p was upregulated in BC tissues and cells. Both circ_SETD2 and SCUBE2 elevation arrested cell cycle progression, inhibited cell proliferation, migration, and invasion, and accelerated cell apoptosis in BC cells. Moreover, circ_SETD2 upregulation repressed BC growth in vivo. Importantly, circ_SETD2 modulated SCUBE2 expression through competitively binding to miR-155-5p in BC cells. Also, the inhibitory impacts of circ_SETD2 enhancement on the malignant behavior of BC cells were restored by miR-155-5p overexpression. Besides, SCUBE2 silencing abolished miR-155-5p downregulation mediated effects on the malignant behavior of BC cells. Therefore, circ_SETD2 curbed BC progression via upregulating SCUBE2 via binding to miR-155-5p.

Circ-PRKDC Facilitates the Progression of Colorectal Cancer Through miR-198/DDR1 Regulatory Axis

Background

Circular RNAs (circRNAs) play a crucial role in a variety of cancers, including colorectal cancer (CRC). This study aimed to explore the role of hsa_circ_0136666 (circ-PRKDC) in CRC and its potential mechanism.

Methods

The levels of circ-PRKDC, miR-198 and discoidin domain receptor 1 (DDR1) were measured using quantitative real-time polymerase chain reaction or Western blot. Cell viability was detected using cell counting kit-8 (CCK-8) assay. Cell apoptosis and cycle were evaluated via flow cytometry. Cell migration and invasion were examined using transwell assay. CyclinD1 protein level was determined via Western blot. The interaction among circ-PRKDC, miR-198 and DDR1 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Xenograft assay was performed to analyze tumor growth in vivo.

Results

Circ-PRKDC and DDR1 levels were increased, and miR-198 level was decreased in CRC tissues and cells. Circ-PRKDC depletion inhibited proliferation, migration and invasion, and expedited apoptosis and cell cycle arrest in SW480 and HCT116 cells. Silence of circ-PRKDC impeded CRC progression by sponging miR-198. Overexpression of miR-198 hindered CRC development via targeting DDR1. Moreover, circ-PRKDC silencing suppressed tumor growth in vivo.

Conclusion

Knockdown of circ-PRKDC inhibited CRC progression via modulating miR-198/DDR1 pathway.

Circ-UBR1 facilitates proliferation, metastasis, and inhibits apoptosis in breast cancer by regulating the miR-1299/CCND1 axis

AIMS

Circular RNA (circRNA) is abnormally expressed in cancers and has been linked to cancer progression, including breast cancer (BC). However, the role and mechanism of circ-UBR1 in BC progression remains to be further studied.

MATERIALS AND METHODS

Quantitative real-time PCR (qRT-PCR) was conducted to analyze the expression of circ-UBR1, miR-1299 and Cyclin D1 (CCND1). Cell counting kit 8 (CCK8) assay was used to measure cell viability. Cell apoptosis and cell cycle distribution were analyzed by flow cytometry. Then, the migration and invasion of cells were determined by transwell assay. Moreover, BC tumor xenograft model was built to evaluate the function of circ-UBR1 silencing on BC tumor volume and weight. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were applied to illuminate the interaction between miR-1299 and circ-UBR1 or CCND1. In addition, relative CCND1 protein expression was assessed using western blot (WB) analysis.

KEY FINDINGS

Our results revealed that circ-UBR1 was upregulated in BC, and its silencing could inhibit BC cell proliferation, metastasis, and promote apoptosis in vitro, as well as restrain BC tumor growth in vivo. Meanwhile, we found that circ-UBR1 could sponge miR-1299, and miR-1299 inhibitor could reverse the effect of circ-UBR1 knockdown on BC cell progression. Furthermore, CCND1 was a target of miR-1299, and CCND1 overexpression could reverse the effect of miR-1299 mimic on BC cell progression. Also, the downregulation of circ-UBR1 could inhibit CCND1 expression, while this effect could be inverted by miR-1299 inhibitor.

SIGNIFICANCE

Our data indicated that circ-UBR1 might play a pro-cancer role in BC progression by regulating the miR-1299/CCND1 axis.

circ_0136666 Facilitates the Progression of Colorectal Cancer via miR-383/CREB1 Axis

Background

The changes in dietary patterns cause an increased incidence of colorectal cancer (CRC) globally. We aimed to explore the mechanism behind circular RNA circ_0136666 in the progression of CRC.

Materials and Methods

The expression of circ_0136666, miR-383 and cAMP response element binding protein 1 (CREB1) was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis and glycolysis were measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry and glucose or lactate detection kit, respectively. The combination between miR-383 and circ_0136666 or CREB1 in 293T cells was predicted by Circular RNA Interactome or Starbase software and confirmed by dual-luciferase reporter assay. Western blot assay was performed to detect the abundance of CREB1, hexokinase 2 (HK2) and lactate dehydrogenase A (LDHA) in CRC cells. Murine xenograft model was established to verify the function of circ_0136666 in vivo.

Results

circ_0136666 was aberrantly up-regulated in CRC tissues and cells, and it promoted the proliferation and glycolysis and inhibited the apoptosis of CRC cells. circ_0136666 accelerated the progression of CRC through directly targeting and down-regulating miR-383. CREB1 could bind to miR-383 in 293T cells. The overexpression of CREB1 reversed the inhibitory effects of miR-383 accumulation on the proliferation and glycolysis and the promoting impact on the apoptosis of CRC cells. The enrichment of CREB1 was modulated by circ_0136666/miR-383 signaling in CRC cells. The glycolysis-related proteins (HK2 and LDHA) were modulated by circ_0136666/miR-383/CREB1 axis in CRC cells. circ_0136666 accelerated the growth of CRC tumors via circ_0136666/miR-383/CREB1 axis in vivo.

Conclusion

circ_0136666 deteriorated CRC through miR-383/CREB1 axis. circ_0136666/miR-383/CREB1 axis might be an underlying therapeutic target for CRC therapy.

miR‑1299/NOTCH3/TUG1 feedback loop contributes to the malignant proliferation of ovarian cancer

Recent studies have revealed the oncogenic role of notch reporter 3 (NOTCH3) in ovarian cancer (OC). However, the possible regulators and mechanisms underlying notch receptor 3 (NOTCH3)‑mediated behaviors in OC remain to be completely investigated. In the present study, we aimed to identify regulators of NOTCH3 and their interactions underlying the pathogenesis of OC. Bioinformatics analysis and luciferase reporter assay were used to identify potential regulatory miRNAs and lncRNAs of NOTCH3 in OC. Several in vivo and in vitro assays were performed to evaluate their effects on the proliferative ability mediated by NOTCH3. We identified microRNA‑1299 (miR‑1299) as a novel negative regulator of NOTCH3. miR‑1299 was downregulated in OC and was found to be considerably correlated with tumor differentiation. Upregulation of miR‑1299 inhibited cell proliferation, colony formation, and 5‑ethynyl‑2'‑deoxyuridine (EdU) incorporation, as well as induced cell cycle arrest in the G0G1 phase in OC cells. Overexpression of miR‑1299 in xenograft mouse models suppressed tumor growth in vivo. The lncRNA taurine upregulated gene 1 (TUG1), acting as a sponge of miR‑1299, was found to upregulate NOTCH3 expression and promote cell proliferation in OC through the competing endogenous RNA mechanism. In addition, TUG1 was found to be a potential downstream target of NOTCH3, forming a miR‑1299/NOTCH3/TUG1 feedback loop in the development of OC. Collectively, our findings improve the understanding of NOTCH3‑mediated regulation in OC pathogenesis and facilitate the development of miRNA‑ and lncRNA‑directed diagnostics and therapeutics against this disease.

lncRNA RHPN1-AS1 Promotes Ovarian Cancer Growth and Invasiveness Through Inhibiting miR-1299

Background

Ovarian cancer (OC) is a big threat for public health. However, the molecular mechanism underlying OC development and progression remains unclear. Although the importance of lncRNA in cancer has been proven, how lncRNA is involved in OC is waiting for further investigation.

Materials and Methods

qRT-PCR was performed to test expression level. CCK8 and colony formation were conducted to analyze proliferation. Transwell was conducted to measure migration and invasion. Luciferase reporter assay and pulldown assay were utilized to validate RNA interaction.

Results

lncRNA RHPN1-AS1 was highly expressed in OC tissues. RHPN1-AS1 was positively correlated with OC progression and its high expression indicated a low survival rate. Moreover, knockdown of RHPN1-AS1 significantly inhibited the proliferation, migration and invasion of OC cells, and bioinformatics analysis identified that miR-1299 was sponged by RHPN1-AS1 in OC cells. Knockdown of RHPN1-AS1 markedly promoted miR-1299 expression. Of note, inhibition of miR-1299 reversed the roles of RHPN1-AS1 silencing on suppressing proliferation, migration and invasion.

Conclusion

Our study demonstrates that RHPN1-AS1 promotes OC progression via sponging miR-1299, suggesting RHPN1-AS1 may be a novel therapeutic target.

Overexpression of hsa_circ_0136666 predicts poor prognosis and initiates osteosarcoma tumorigenesis through miR-593-3p/ZEB2 pathway

Background: Osteosarcoma (OS) is a type of malignant bone tumor with a growing incidence. Increasing studies indicate circular RNA (circRNA) has a vital function in tumorigenesis. Yet, how circRNA regulates OS development is not clear. In the present work, we aimed to investigate the roles of hsa_circ_0136666 in OS progression.

Results: hsa_circ_0136666 was shown to be upregulated in OS and correlated with advanced stage and poor prognosis. Functional investigation using CCK8, colony formation assay and Transwell assay demonstrated that hsa_circ_0136666 promoted OS proliferation, migration and invasion, but inhibited cell death. Additionally, we identified hsa_circ_0136666 was a molecular sponge for miR-593-3p to facilitate ZEB2 expression. MiR-593-3p and ZEB2 were inversely expressed in OS tissues. And hsa_circ_0136666 exerts oncogenic roles in OS relying on miR-593-3p and ZEB2.

Conclusion: Our results demonstrate the involvement of hsa_circ_0136666 in regulating OS tumorigenesis and it may be a therapeutic target.

Methods: The expression of hsa_circ_0136666 was analyzed by qRT-PCR in OS tissues and cell lines. Proliferation was measured via CCK8 and colony formation assays. Migration and invasion were determined through Transwell assay. Luciferase reporter assay was utilized to determine the interaction between hsa_circ_0136666 and miR-593-3p or between miR-593-3p and ZEB2. Animal experiment was performed to investigate the role of hsa_circ_0136666 in vivo.

The Roles of Cyclin-Dependent Kinases in Cell-Cycle Progression and Therapeutic Strategies in Human Breast Cancer

Cyclin-dependent kinases (CDKs) are serine/threonine kinases whose catalytic activities are regulated by interactions with cyclins and CDK inhibitors (CKIs). CDKs are key regulatory enzymes involved in cell proliferation through regulating cell-cycle checkpoints and transcriptional events in response to extracellular and intracellular signals. Not surprisingly, the dysregulation of CDKs is a hallmark of cancers, and inhibition of specific members is considered an attractive target in cancer therapy. In breast cancer (BC), dual CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, combined with other agents, were approved by the Food and Drug Administration (FDA) recently for the treatment of hormone receptor positive (HR+) advanced or metastatic breast cancer (A/MBC), as well as other sub-types of breast cancer. Furthermore, ongoing studies identified more selective CDK inhibitors as promising clinical targets. In this review, we focus on the roles of CDKs in driving cell-cycle progression, cell-cycle checkpoints, and transcriptional regulation, a highlight of dysregulated CDK activation in BC. We also discuss the most relevant CDK inhibitors currently in clinical BC trials, with special emphasis on CDK4/6 inhibitors used for the treatment of estrogen receptor-positive (ER+)/human epidermal growth factor 2-negative (HER2−) M/ABC patients, as well as more emerging precise therapeutic strategies, such as combination therapies and microRNA (miRNA) therapy.

The positive feedback loop of RHPN1-AS1/miR-1299/ETS1 accelerates the deterioration of gastric cancer

Gastric cancer (GC) is the most prevailing malignant tumor of digestive tract and accounts for a considerable part of cancer-relevant deaths worldwide. An increasing number of literatures highlight the important role of lncRNAs in the occurrence and development of GC. Considering that the function of RHPN1-AS1 in GC remains to be fully inquired, we purposed to investigate the potential and mechanism of RHPN1-AS1 in GC. The expression of RHPN1-AS1 was significantly upregulated in GC samples and cells. High RHPN1-AS1 level was strongly correlated with advanced stages of GC and predicted poor outcomes of GC. Furthermore, depletion of RHPN1-AS1 inhibited cell proliferation and cell cycle whereas promoted cell apoptosis. Subcellular fractionation analysis expounded the main expression of RHPN1-AS1 in GC cell cytoplasm. Herein, we conjectured that RHPN1-AS1 might exert its performance in GC through the ceRNA network. Our findings demonstrated that RHPN1-AS1 enhanced ETS1 expression via sponging miR-1299. More importantly, the transcriptional activation of RHPN1-AS1 was mediated by ETS1. Results of recue assays validated that RHPN1-AS1/miR-1299/ETS1 positive feedback loop aggravated the malignant behaviors of GC, revealing RHPN1-AS1 as a latent effective target for the treatment of GC patients.

Circular RNA circ-EGLN3 promotes renal cell carcinoma proliferation and aggressiveness via miR-1299-mediated IRF7 activation

Renal cell carcinoma (RCC) is a highly lethal cancer with increasing incidence worldwide. The purpose of the present study was to investigate the functions and molecular mechanisms of circular RNA (circRNA), circ-EGLN3, in RCC progression. The expression levels of circ-EGLN3 were assessed by a quantitative real-time polymerase chain reaction. Kaplan-Meier analysis was applied to uncover the prognostic role of circ-EGLN3 in patients with RCC. Cell viability was analyzed using cell counting kit-8 and cell apoptosis was assessed using flow cytometric experiment. Cell migratory and invasive abilities were determined by wound scratch and transwell experiments. Subcellular distribution detection was utilized to investigate the location of circ-EGLN3. Dual-luciferase reporter test was utilized for identifying the molecular mechanism of circ-EGLN3. The results indicated that circ-EGLN3 was elevated in RCC tissues and cell lines and predicted unfavorable prognosis for the patients with RCC. Silenced circ-EGLN3 hindered cell proliferation, migration, and invasion but facilitated apoptosis of RCC cells. Ectopic expressed circ-EGLN3 induced the opposite effects mentioned above. Mechanistically, circ-EGLN3 was mainly located at the cytoplasm. Circ-EGLN3 acted as a competing endogenous RNA (ceRNA) to enhance the IRF7 level via sponging miR-1299. Moreover, circ-EGLN3 mediated elevation of IRF7 is responsible for RCC cell proliferation and aggressiveness. Collectively, our study suggested that circ-EGLN3 knockdown suppressed RCC progression through acting as a ceRNA to regulate the IRF7 expression by targeting miR-1299. Circ-EGLN3 might be a potential therapeutic target for RCC management.

DNA Dumbbell and Chameleon Silver Nanoclusters for miRNA Logic Operations

Multiplex miRNA analysis is a fundamental issue for exploring a complex biological system and early diagnosis of miRNA-related diseases. Herein, we have developed a series of novel logic gates for miRNA analysis coupling DNA nanostructures and chameleon silver nanoclusters (AgNCs). DNA dumbbell structures are firstly designed with two independent nucleation sequences for AgNCs at the 5' and 3' ends, respectively. By introducing different miRNA inputs, separations of two AgNCs are controlled and the fluorescence property of AgNCs changes. By studying the ratiometric fluorescence responses, sensitive and selective analysis of multiple miRNAs can be achieved. The present work provides powerful tools for miRNA diagnostics and may also guide future DNA nanostructure-based logic gates.