circRNA-miRNA-mRNA in breast cancer

PRKCA Promotes Mitophagy through the miR-15a-5p/PDK4 Axis to Relieve Sepsis-Induced Acute Lung Injury

Acute lung injury (ALI) caused by sepsis is a common respiratory critical illness with high morbidity and mortality. Protein kinase C-alpha (PRKCA) plays a protective role in sepsis-induced ALI. However, the detailed molecular mechanism of PRKCA in ALI caused by sepsis is unclear. Animal and cell models of sepsis were established by cecal ligation and puncture (CLP)-surgery and lipopolysaccharide (LPS)/interferon-gamma (IFN-γ) treatment, respectively. Lentivirus transfection was used to overexpress PRKCA. H&E staining and lung injury in CLP-surgery mice were evaluated. Gene expression was evaluated using qPCR and Western blotting. The expression of TNF-α, IL-1β, and IL-6 was examined using qPCR and ELISA. The expression of LC3 and TOM20 was evaluated using immunofluorescence assays. Cell apoptosis was assessed using a flow cytometry assay. The bond between miR-15a-5p and PDK4 was confirmed by dual-luciferase reporter gene and RNA immunoprecipitation assays. In vivo and in vitro, PRKCA overexpression reduced lung injury to prompt mitophagy and inhibit the inflammatory response, ROS production, and cell apoptosis. miR-15a-5p was highly expressed in macrophages treated with LPS/IFN-γ and was negatively mediated by PRKCA. The overexpression of miR-15a-5p reduced the effects of PRKCA upregulation in macrophages. miR-15a-5p could restrain mitophagy in LPS/IFN-γ-treated macrophages by directly targeting PDK4. Furthermore, PDK4 knockdown reversed the inhibition of cell apoptosis and inflammatory factor release caused by miR-15a-5p silencing. The PRKCA/miR-15a-5p/PDK4 axis alleviated ALI caused by sepsis by promoting mitophagy and repressing anti-inflammatory response.

Protective role of circRNA CCND1 in ulcerative colitis via miR-142-5p/NCOA3 axis

BACKGROUND

Increasing research indicates that circular RNAs (circRNAs) play critical roles in the development of ulcerative colitis (UC). This study aimed to determine the role of circRNA CCND1 in UC bio-progression, which has been shown to be downregulated in UC tissues.

METHODS

Reverse transcription quantitative polymerase chain reaction was used to determine the levels of circRNA CCND1, miR-142-5p, and nuclear receptor coactivator-3 (NCOA3) in UC tissues and in lipopolysaccharide (LPS)-induced Caco-2 cells. Target sites of circRNA CCND1 and miR-142-5p were predicted using StarBase, and TargetScan to forecast potential linkage points of NCOA3 and miR-142-5p, which were confirmed by a double luciferase reporter-gene assay. Cell Counting Kit 8 and flow cytometry assays were performed to assess Caco-2 cell viability and apoptosis. TNF-α, IL-1β, IL-6, and IL-8 were detected using Enzyme-Linked Immunosorbent Assay kits.

RESULTS

CircRNA CCND1 was downregulated in UC clinical samples and LPS-induced Caco-2 cells. In addition, circRNA CCND1 overexpression suppressed LPS-induced apoptosis and inflammatory responses in Caco-2 cells. Dual-luciferase reporter-gene assays showed that miR-142-5p could be linked to circRNA CCND1. Moreover, miR-142-5p was found to be highly expressed in UC, and its silencing inhibited LPS-stimulated Caco-2 cell apoptosis and inflammatory responses. Importantly, NCOA3 was found downstream of miR-142-5p. Overexpression of miR-142-5p reversed the inhibitory effect of circRNA CCND1-plasmid on LPS-stimulated Caco-2 cells, and the effects of miR-142-5p inhibitor were reversed by si-NCOA3.

CONCLUSION

CircRNA CCND1 is involved in UC development by dampening miR-142-5p function, and may represent a novel approach for treating UC patients.

ncRNAs mediated RPS6KA2 inhibits ovarian cancer proliferation via p38/MAPK signaling pathway

Background

Ovarian cancer is the most lethal gynecology malignancy in the world, therefore, research on the molecular biological mechanism of ovarian cancer tumorigenesis and progression has received widespread attention.

Methods

We identified RPS6KA2 as the prognosis-related gene of ovarian cancer from TCGA, GSE26712 and GSE26193 database via bioinformatic analysis. qRT-PCR and western blot detected the differential expression of RPS6KA2 in normal ovaries and ovarian cancer tissues. The biological functions of RPS6KA2 were verified by in vitro and in vivo. GSEA analysis was used to select candidate signaling pathway of RPS6KA2 which was further verified by western blot. The possible binding sites of RPS6KA2 with miRNAs and circRNAs were predicted by bioinformatics analysis, and then a circRNA-miRNA-mRNA interaction network was constructed.

Results

We found the expression of RPS6KA2 was down-regulated in ovarian cancer tissues. Overexpression of RPS6KA2 could suppress cell proliferation, whereas knockdown of RPS6KA2 had the opposite effects on proliferation. GSEA analysis showed that the MARK signaling pathway was closely associated with RPS6KA2. Bioinformatics analysis and dual-luciferase reporter assay showed that RPS6KA2 was regulated with miR-19a-3p, miR-106a-5p and miR-519d-3p. Further analysis showed that circFAM169A was the common ceRNA of miR-19a-3p, miR-106a-5p and miR-519d-3p. Dual-luciferase reporter assay showed the relationship of circFAM169A and miR-106a-5p and miR-519d-3p. After network analysis, one circRNA-miRNA-mRNA axis (circFAM169A/miR-106a-5p, miR-519d-3p/RPS6KA2) was identified.

Conclusions

We demonstrated that circFAM169A/miR-106a-5p, miR-519d-3p mediated low expression of RPS6KA2 could affect the proliferation of ovarian cancer cells via p38/MAPK signaling pathway.

circHECTD1 Promotes the Proliferation and Migration of Human Brain Vascular Smooth Muscle Cells via Interacting with KHDRBS3 to Stabilize EZH2 mRNA Expression

Purpose

The objective of this paper is to explore the role of circHECTD1 in vascular smooth muscle cells (VSMCs) and atherosclerosis (AS).

Methods

VSMCs were treated with platelet-derived growth factor-BB (PDGF-BB) in vitro, and the level of circHECTD1 was determined using qRT-PCR. Cell proliferation, migration, and invasion were analyzed using CCK8 and transwell assays. Cell apoptosis and cell cycle were analyzed using flow cytometry. The binding interaction between circHECTD1 and KHDRBS3 or EZH2 was investigated using the RIP, RNA pull-down.

Results

CircHECTD1 was upregulated in PDGF-BB-induced VSMCs with a dose-dependent and time-dependent manner. Knockdown of circHECTD1 suppressed VSMCsproliferation and migration and enhanced cell apoptosis in VSMCs, while circHECTD1 overexpression yielded opposite effects. Mechanistically, circHECTD1 could interact with KHDRBS3, thus enhanced the stability of EZH2 mRNA and increased EZH2 protein level. In addition, silencing EZH2 in VSMCs reversed the proliferation-enhancing effect of circHECTD1 overexpression.

Conclusion

Our findings provided providing a potential prognostic and therapy biomarker for AS.

siRNA and targeted delivery systems in breast cancer therapy

Recently, nucleic acid drugs have been considered as promising candidates in treatment of various diseases, especially cancer. Because of developing resistance to conventional chemotherapy, use of genetic tools in cancer therapy appears inevitable. siRNA is a RNAi tool with capacity of suppressing target gene. Owing to overexpression of oncogenic factors in cancer, siRNA can be used for suppressing those pathways. This review emphasizes the function of siRNA in treatment of breast tumor. The anti-apoptotic-related genes including Bcl-2, Bcl-xL and survivin can be down-regulated by siRNA in triggering cell death in breast cancer. STAT3, STAT8, Notch1, E2F3 and NF-κB are among the factors with overexpression in breast cancer that their silencing by siRNA paves the way for impairing tumor proliferation and invasion. The oncogenic mechanisms in drug resistance development in breast tumor such as lncRNAs can be suppressed by siRNA. Furthermore, siRNA reducing P-gp activity can increase drug internalization in tumor cells. Because of siRNA degradation at bloodstream and low accumulation at tumor site, nanoplatforms have been employed for siRNA delivery to suppress breast tumor progression via improving siRNA efficacy in gene silencing. Development of biocompatible and efficient nanostructures for siRNA delivery can make milestone progress in alleviation of breast cancer patients.

Potential Impact of Preoperative Circulating Biomarkers on Individual Escalating/de-Escalating Strategies in Early Breast Cancer

The research on non-invasive circulating biomarkers to guide clinical decision is in wide expansion, including the earliest disease settings. Several new intensification/de-intensification strategies are approaching clinical practice, personalizing the treatment for each patient. Moreover, liquid biopsy is revealing its potential with multiple techniques and studies available on circulating biomarkers in the preoperative phase. Inflammatory circulating cells, circulating tumor cells (CTCs), cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), and other biological biomarkers are improving the armamentarium for treatment selection. Defining the escalation and de-escalation of treatments is a mainstay of personalized medicine in early breast cancer. In this review, we delineate the studies investigating the possible application of these non-invasive tools to give a more enlightened approach to escalating/de-escalating strategies in early breast cancer.

Predictive value of PD-L1 expression to the efficacy of immune checkpoint inhibitors in advanced triple-negative breast cancer: A systematic review and meta-analysis

Background: Immune checkpoint inhibitors (ICIs) have been an emerging treatment strategy for advanced triple-negative breast cancer (TNBC). Some studies have shown that high expression of programmed death-ligand 1 (PD-L1) can achieve a better response of clinical efficacy. However, the efficacy of ICIs in advanced TNBC remains controversial. In this meta-analysis, we evaluated the correlation of PD-L1 expression with the efficacy of ICIs in patients with advanced TNBC. Methods: We conducted a systematic search using four databases until March 2022 to obtain eligible randomized controlled trials (RCTs). The quality of the studies was assessed by the Cochrane risk of bias tool. Hazard ratio (HR) was extracted to evaluate the relationship between PD-L1 expression and progression-free survival (PFS) or overall survival (OS) in patients with advanced TNBC. Results: Five randomized controlled clinical trials (RCTs) with 3104 patients were included in this meta-analysis. The results demonstrated that ICIs could significantly improve the OS (HR 0.77, 95% CI 0.60-0.98, p = 0.03) in PD-L1 positive TNBC group. In the subgroup analysis, longer OS was observed (HR: 0.70, 95% CI: 0.60-0.82, p = 0.00001) in PD-L1 positive TNBC patients receiving ICIs alone or ICIs combined with nab-paclitaxel. In terms of PFS, PFS was significantly improved (HR: 0.68, 95% CI: 0.58-0.79, p < 0.00001) in PD-L1 positive patients receiving first-line ICIs and chemotherapy compared to those with ICIs alone. No significant improvement was observed for OS or PFS in PD-L1 negative group. Conclusion: Our study indicated significant improvement for OS in advanced TNBC with ICIs therapy in the PD-L1 positive status, and ICIs alone or ICIs combined with nab-paclitaxel might be a excellent choice in terms of OS. Although PFS has no significant benefit in PD-L1 positive patients, the subgroup analysis showed that ICIs combined with chemotherapy could achieve the PFS benefit in the first-line treatment. However, further clinical studies are needed to validate our conclusions due to limited relevant research.

HBV Promotes the Proliferation of Liver Cancer Cells through the hsa_circ_0000847/miR-135a Pathway

Hepatocellular carcinoma (HCC) is currently one of the most common tumors, with a high morbidity and mortality rate. HCC induced by persistent hepatitis B virus (HBV) infection is the most common liver cancer subtype at present, and HBV-related HCC is highly malignant and its development mechanism still needs to be explored in depth. This study aimed to explore the molecular mechanism of hsa_circ_0000847 targeting miR-135a-5p (miR-135a) to regulate the proliferation, invasion, and apoptosis of liver cancer cells. The study found that the expression level of hsa_circ_0000847 in liver cancer tissues and cells was significantly increased, while the expression level of miR-135a was significantly decreased. Hsa_circ_0000847 promoted the proliferation of liver cancer cells and elevated the expression of the proliferation-related protein. In addition, hsa_circ_0000847 could promote the invasion of HBV-infected liver cancer cells and inhibit the cell apoptosis of liver cancer cells. At the same time, it significantly promoted the expression of antiapoptotic proteins and inhibited the expression of proapoptotic protein. Interestingly, the dual luciferase experiment proved that hsa_circ_0000847 directly targeted miR-135a. On the other hand, the combined effect of hsa_circ_0000847 and miR-135a further illustrated the effect of hsa_circ_0000847 on the proliferation, invasion, and apoptosis of liver cancer cells. In addition, further experiments have also found that HBV could promote the expression of p-p38, p-ERK, and p-JNK through the hsa_circ_0000847/miR-135a axis, thereby further activating the MAPK pathway. In short, HBV promotes the proliferation and invasion of liver cancer cells and inhibits apoptosis by regulating the hsa_circ_0000847/miR-135a pathway, which provided a theoretical basis for effective treatment of HBV-infected liver cancers.

The role of CircRNA/miRNA/mRNA axis in breast cancer drug resistance

Multidrug resistance is one of the major obstacles in the treatment of cancers. This undesirable feature increases the mortality rate of cancers, including breast cancer. Circular RNA (CircRNA)/microRNA (miRNA)/messenger RNA (mRNA) is one of the important axes with major roles in the promotion and resistance of breast cancer. This heterogeneous pathway includes mRNA of oncogenes and tumor suppressors, which are controlled by miRNAs and CircRNAs. Unfortunately, this network could be easily deregulated, resulting in drug resistance and tumor development. Therefore, understanding these dysregulations may thus help to identify effective therapeutic targets. On this basis, we try to review the latest findings in the field, which could help us to better comprehend this significant axis in breast cancer.

The Expression of miR-205 in Prostate Carcinoma and the Relationship with Prognosis in Patients

Purpose. We aimed to investigate the changes of serum and cell exosome miR-205 levels in patients with prostate carcinoma and its clinical significance. Materials and Methods. Firstly, pronouncement of miR-205 in normal and prostate carcinoma tissues was analyzed by using UALCAN database. The relationship between miR-205 in tumor tissues and the pathological and clinical characteristics of patients with prostate carcinoma were analyzed. Consequently, 60 people with prostate carcinoma were collected to the Minhang Hospital from August 2016 to August 2021. Serum of patients in the two groups was collected, and RNA in serum exosomes was extracted, and qRT-PCR was used to analyze the expression of miR-205 mediated by serum exosomes. Meanwhile, the relationship among the clinical as well as pathological aspects and bodement of patients with prostate carcinoma and the pronouncement level of miR-205 mediated by exosome was compared. Next, assays like wound healing and CKK-8 were used to investigate the effects of miR-205 in exosomes extracted from prostate carcinoma on the augmentation and metastasis of prostate carcinoma. Results. The results showed that the pronouncement level of miR-205 in tissues with prostate carcinoma was significantly lower than that in normal prostate tissues. In addition, the pronouncement level of miR-205 in fluid exosome of people with prostate carcinoma and exosomes derived from the lines of prostate carcinoma was considerably less than that in serum exosomes of healthy patients and that of normal cell lines of prostate. The pronouncement level of miR-205 in fluid exosomes of people with prostate carcinoma was negatively associated with cancer phase, uncontrolled cell division in lymph nodes, distant metastasis, and PSA level at initial diagnosis. Analysis (multivariate and univariate) showed that miR-205 pronouncement was a sovereign threat cause for prognosis of prostate cancer patients. Additionally, the pronouncement and metastasis of prostate carcinoma can be restricted by the overexpression of miR-205. Conclusion. The pronouncement of miR-205 in liquid derived exosomes is correlated with the prediction of people with prostate carcinoma and may be a new marker for identification and cure of prostate carcinoma.

N6-methyladenosine-mediated upregulation of LINC00520 accelerates breast cancer progression via regulating miR-577/POSTN axis and downstream ILK/AKT/mTOR signaling pathway

Various lncRNAs have been reported to be closely associated with cancer initiation and progression in breast cancer (BC), including LINC00520. However, the role and underlying mechanisms by which LINC00520 affects BC aggressiveness have not been fully delineated, and this study aimed to explore this issue. Through performing qRT-PCR analysis, we proved that LINC00520 was significantly upregulated in BC tissues and cells, compared with normal tissues and cells. Higher expression of LINC00520 was closely related to higher tumor grade, poor differentiation and shorter survival in BC patients. Next, the loss-of-function experiments evidenced that silencing LINC00520 suppressed BC cell proliferation, migration and epithelial-mesenchymal transition (EMT) in vitro, and inhibited tumorigenesis in vivo. Interestingly, we found that LINC00520 expression was positively regulated by METTL3-mediated N6-methyladenosine(m⁶A) modification in BC. Furthermore, we identified the tumor-suppressor miR-577 as the binding target of LINC00520 in BC. Mechanistically, LINC00520 elevated POSTN level via sponging miR-577, resulting in the activation of the downstream tumor-promoting ILK/Akt/mTOR pathway. Finally, the rescuing experiments evidenced that both POSTN knockdown and ILK/Akt/mTOR pathway inhibitor OSU-T315 abrogated the promoting effects of miR-577 ablation on the malignant phenotypes in BC. Collectively, this study firstly verified that LINC00520 acted as a ceRNA of miR-577 to advance BC aggressiveness in a m⁶A-dependent manner, providing novel biomarkers for BC diagnosis and therapy.

Differential expression profile of mRNAs, lncRNAs and circRNAs reveals potential molecular mechanism in breast cancer

In recent years, breast cancer attracts more and more attention because of its high incidence. To explore the molecular functions and mechanisms, we performed RNA sequencing on the tumor tissues and their paired normal tissues from three breast cancer patients. By differential expression analysis, we found 3764 differentially expressed (DE) mRNAs, 5416 DE lncRNAs, and 148 DE circRNAs. Enrichment analysis suggested that the DE lncRNAs and DE circRNAs were enriched in mitochondria and nucleus, which indicated that they may participate in the vital metabolism directly or indirectly, such as fatty acid metabolism. Subsequently, the protein–protein interaction (PPI) network was constructed and we got 8 key proteins, of which the matrix metalloproteinase-9 (MMP9; degree 5) draws our attention. Based on the 38 up-regulated circRNAs and 14 down-regulated circRNAs, we constructed competing endogenous RNA (ceRNA) networks, from which the has-miR-6794-5p has been identified to enriched in the up-regulated network and correlated with the circNFIX directly. At this point, we presented that the circNFIX and MMP9 may play a significant role by regulating fatty acid metabolism in breast cancer.

Extracellular Vesicles-ceRNAs as Ovarian Cancer Biomarkers: Looking into circRNA-miRNA-mRNA Code

Simple Summary

Patients with ovarian cancer have a very poor chance of long-term survival, usually due to advanced disease at the time of diagnosis. Emerging evidence suggests that extracellular vesicles contain noncoding RNAs such as microRNAs, piwiRNAs, circular RNAs, and long noncoding RNAs, with regulatory effects on ovarian cancer. In this review, we focus on ovarian cancer-associated circular RNA shuttled by extracellular vesicles as mediators of cancer progression and novel biomarkers in liquid biopsy. We propose a circular-RNA–microRNA-mRNA code that can reveal the regulatory network created by extracellular vesicles, noncoding RNAs, and mRNAs in ovarian cancer. Future research in this field will help to identify novel diagnostic biomarkers and druggable therapeutic targets, which will ultimately benefit patients.

Abstract

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies in females worldwide. OC is frequently diagnosed at an advanced stage due to a lack of specific symptoms and effective screening tests, resulting in a poor prognosis for patients. Age, genetic alterations, and family history are the major risk factors for OC pathogenesis. Understanding the molecular mechanisms underlying OC progression, identifying new biomarkers for early detection, and discovering potential targets for new drugs are urgent needs. Liquid biopsy (LB), used for cancer detection and management, consists of a minimally invasive approach and practical alternative source to investigate tumor alterations by testing extracellular vesicles (EVs), circulating tumor cells, tumor-educated platelets, and cell-free nucleic acids. EVs are nanosize vesicles shuttling proteins, lipids, and nucleic acids, such as DNA, RNA, and non-coding RNAs (ncRNAs), that can induce phenotypic reprogramming of target cells. EVs are natural intercellular shuttles for ncRNAs, such as microRNAs (miRNAs) and circular-RNAs (circRNAs), known to have regulatory effects in OC. Here we focus on the involvement of circRNAs and miRNAs in OC cancer progression. The circRNA-microRNA-mRNA axis has been investigated with Circbank and miRwalk analysis, unraveling the intricate and detailed regulatory network created by EVs, ncRNAs, and mRNAs in OC.

circACTG1 Promotes Hepatocellular Carcinoma Progression by Regulating miR-940/RIF1 Axis and Activating AKT/mTOR Pathway

Background

Hepatocellular carcinoma (HCC) is recognized as the fourth in incidence and the third in mortality worldwide. The onset of HCC is insidious and often asymptomatic at the early stage. HCC is more prone to metastasis, recurrence, and drug resistance than other solid tumors owing to its feature of high heterogeneity. Therefore, what particularly important is to search for effective molecular markers in the occurrence and progression of HCC.

Aim

To probe into the therapeutic potential of circACTG1 (hsa_circ_0046144) in HCC cell migration and invasion, providing a new insight and molecular target to diagnose and cure HCC patients.

Methods

The circACTG1 expression in collected HCC cells was determined by quantitative polymerase chain reaction (qPCR). Assessment for circACTG1 diagnosing capability was analyzed by receiver operating characteristic (ROC) curves. Transwell assay, wound healing assay, and cell counting kit-8 assay were used for monitoring the effect of circACTG1 in HCC cell invasion, migration, and proliferation, respectively; qPCR, luciferase reporter assay, databases, and Western blot analysis were used for identifying the modulation mechanisms among circACTG1, miRNA-940, and RIF1. What is more, our study verified AKT-mTOR signaling after miR-940 mimic treatment or circACTG1 knockdown.

Results

circACTG1 was overexpressed in HCC cells and tissues. Knockdown of circACTG1 restrained 97H and Huh7 cell migration and invasion. Significantly, circACTG1 was discovered to serve as a miR-940 sponge. miR-940 activation rebated the circACTG1 level, and conversely, miR-940 inhibition boosted the circACTG1 level. However, this effect or relationship was not seen after circACTG1 mutation. Furtherly, miR-940-downregulated expression was also found in HCC patients, and importantly, miR-940 inhibition reversed circACTG1 expression in 97H cells with circACTG1 knockdown. Moreover, the expression of RIF1 was significantly reduced after inhibiting circACTG1 or overexpressing miR-940 but rescued when both circACTG1 and miR-940 were inhibited. Finally, circACTG1 and miR-940 played significant roles of regulating AKT-mTOR signaling.

Conclusion

circACTG1 expression remarkably ascended in HCC, which is of certain diagnostic value. Moreover, circACTG1 potentially regulates HCC cell proliferation, invasion, and migration via miR-940/RIF1/AKT/mTOR pathway.

Non-Coding RNA Networks as Potential Novel Biomarker and Therapeutic Target for Sepsis and Sepsis-Related Multi-Organ Failure

According to “Sepsis-3” consensus, sepsis is a life-threatening clinical syndrome caused by a dysregulated inflammatory host response to infection. A rapid identification of sepsis is mandatory, as the extent of the organ damage triggered by both the pathogen itself and the host’s immune response could abruptly evolve to multiple organ failure and ultimately lead to the death of the patient. The most commonly used therapeutic strategy is to provide hemodynamic and global support to the patient and to rapidly initiate broad-spectrum empiric antibiotic therapy. To date, there is no gold standard diagnostic test that can ascertain the diagnosis of sepsis. Therefore, once sepsis is suspected, the presence of organ dysfunction can be assessed using the Sepsis-related Organ Failure Assessment (SOFA) score, although the diagnosis continues to depend primarily on clinical judgment. Clinicians can now rely on several serum biomarkers for the diagnosis of sepsis (e.g., procalcitonin), and promising new biomarkers have been evaluated, e.g., presepsin and adrenomedullin, although their clinical relevance in the hospital setting is still under discussion. Non-codingRNA, including long non-codingRNAs (lncRNAs), circularRNAs (circRNAs) and microRNAs (miRNAs), take part in a complex chain of events playing a pivotal role in several important regulatory processes in humans. In this narrative review we summarize and then analyze the function of circRNAs-miRNA-mRNA networks as putative novel biomarkers and therapeutic targets for sepsis, focusing only on data collected in clinical settings in humans.

CircRNA protein tyrosine phosphatase receptor type a suppresses proliferation and induces apoptosis of lung adenocarcinoma cells via regulation of microRNA-582-3p

Circular RNAs (circRNAs) are associated with cancer progression. The present study aimed to examine the function of circRNA protein tyrosine phosphatase receptor type A (circRNA_PTPRA) in lung cancer cells and elucidate the underlying molecular mechanisms. The levels of circRNA_PTPRA and microRNA (miRNA/miR)-582-3p were measured in lung cancer tissue and cells using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell proliferation and apoptosis were evaluated using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. The expression of cyclin D1, caspase-3, and cleaved caspase-3 was assessed via western blotting. The sites of circRNA_PTPRA/miR-582-3p interaction were identified using StarBase, and validated using a dual-luciferase reporter assay. We observed that circRNA_PTPRA levels were remarkably decreased, and miR-582-3p expression was up-regulated in lung cancer tissues and cells. circRNA_PTPRA directly interacts with miR-582-3p and downregulates miR-582-3p expression in lung cancer cells. Moreover, an miR-582-3p inhibitor decreased lung cancer cell proliferation and promoted apoptosis. The overexpression of circRNA_PTPRA decreased cell proliferation and increased apoptotic cell numbers, whereas miR-582-3p overexpression reversed these effects. These findings demonstrate that the up-regulation of circRNA_PTPRA significantly reduces lung cancer cell proliferation and induces apoptosis by regulating miR-582-3p expression.

Cisplatin resistance and malignant behaviors of lung cancer cells are promoted by circ_0002360 via targeting miR-6751-3p to regulate the expression of ZNF300

BACKGROUND

Circular RNAs (circRNAs) are key regulators in oncogenesis and chemoresistance of human cancers. Herein, we focused on the roles of circ_0002360 in regulating lung cancer progression and cisplatin (DDP) resistance.

METHODS

The detection of circ_0002360, microRNA-6751-3p (miR-6751-3p) and zinc finger protein 300 (ZNF300) was conducted via reverse transcription-quantitative polymerase chain reaction assay. Cell sensitivity was determined using cell counting kit-8 assay. Proliferation detection was performed by colony formation assay and EdU assay. The migrated cells were examined via transwell assay. Cell apoptosis analysis was carried out through flow cytometry and caspase 3 activity assay. Western blot was used to examine the protein levels. Target interaction was confirmed through dual-luciferase reporter assay and RNA immunoprecipitation assay. Circ_0002360 function in vivo was performed via xenograft tumor assay.

RESULTS

Circ_0002360 was overexpressed in DDP-resistant lung cancer tissues and cells. Silencing circ_0002360 inhibited DDP resistance, proliferation and migration but enhanced apoptosis of DDP-resistant cells. Circ_0002360 could elevate ZNF300 expression. DDP resistance and lung cancer progression were also impeded by ZNF300 downregulation. ZNF300 overexpression reversed the function of circ_0002360 knockdown in DDP-resistant lung cancer cells. The regulation of circ_0002360 for ZNF300 was achieved by sponging miR-6751-3p. Circ_0002360 promoted DDP resistance in xenograft mice through mediating the miR-6751-3p/ZNF300 axis.

CONCLUSION

Circ_0002360 targeted miR-6751-3p to regulate ZNF300 level, thus elevating DDP resistance and promoting the malignant progression of lung cancer cells.

Functional Interactions Between lncRNAs/circRNAs and miRNAs: Insights Into Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases that affect synovitis, bone, cartilage, and joint. RA leads to bone and cartilage damage and extra-articular disorders. However, the pathogenesis of RA is still unclear, and the lack of effective early diagnosis and treatment causes severe disability, and ultimately, early death. Accumulating evidence revealed that the regulatory network that includes long non-coding RNAs (lncRNAs)/circular RNAs (circRNAs), micro RNAs (miRNAs), and messenger RNAs (mRNA) plays important roles in regulating the pathological and physiological processes in RA. lncRNAs/circRNAs act as the miRNA sponge and competitively bind to miRNA to regulate the expression mRNA in synovial tissue, FLS, and PBMC, participate in the regulation of proliferation, apoptosis, invasion, and inflammatory response. Thereby providing new strategies for its diagnosis and treatment. In this review, we comprehensively summarized the regulatory mechanisms of lncRNA/circRNA-miRNA-mRNA network and the potential roles of non-coding RNAs as biomarkers and therapeutic targets for the diagnosis and treatment of RA.

Secreted Non-Coding RNAs: Functional Impact on the Tumor Microenvironment and Clinical Relevance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subtype of breast carcinoma characterized by poor prognosis and high rate of metastasis. Current treatment is based on chemo- and/or radiotherapy and surgery. TNBC is devoid of estrogen, progesterone and HER2 receptors. Although precision medicine has come a long way to ameliorate breast cancer disease management, targeted therapies for the treatment of TNBC patients are still limited. Mounting evidence has shown that non-coding RNAs (ncRNAs) drive many oncogenic processes at the basis of increased proliferation, invasion and angiogenesis in TNBC, strongly contributing to tumor progression and resistance to treatments. Many of these ncRNAs are secreted in the tumor microenvironment (TME) and impinge on the activity of the diverse immune and stromal cell types infiltrating the TME. Importantly, secreted ncRNAs may be detected as circulating molecules in serum/plasma from cancer patients and are emerging a promising diagnostic/therapeutic tools in TNBC. This review aims to discuss novel insights about the role of secreted circulating ncRNAs in the intercellular communication in the tumor microenvironment and their potential clinical use as diagnostic and prognostic non-invasive biomarkers in TNBC.