Dual strands of the miR-223 duplex (miR-223-5p and miR-223-3p) inhibit cancer cell aggressiveness: targeted genes are involved in bladder cancer pathogenesis

MicroRNA-223-3p downregulates the inflammatory response in preeclampsia placenta via targeting NLRP3

OBJECTIVE

To investigate the regulatory role of miR-223-3p in the inflammatory response of PE placenta.

METHODS

PE and normal placental tissues were collected to measure the expression of NLRP3 and miR-223-3p. The targeting relationship between NLRP3 and miR-223-3P was verified by bioinformatics analysis and classical double-luciferase reporter gene assay. Lipopolysaccharide (LPS) was used to induce HTR8/SVneo cells as PE placental cell inflammation model. Then we transfected miR-223-3p overexpression/miR-223-3p negative control plasmid into the LPS-induced HTR8/SVneo cells. Next, the expressions of NLRP3, Caspase-1, GSDMD, IL-1β and IL-18 were evaluated to elucidate the regulatory effect of miR-223-3p on the inflammatory response mediated by NLRP3 in PE placenta.

RESULTS

Compared with normal controls, NLRP3 was significantly up-regulated in PE placenta, while miR-223-3p was down-regulated. In addition, NLRP3 was a direct target of miR-223-3p. Further research revealed that the expression of NLRP3, Caspase-1, GSDMD, IL-1β and IL-18 could be obviously promoted in HTR8/SVneo cells treated with LPS (500 ng/ml) for 24 h, nevertheless it could be significantly suppressesed under the overexpression of miR-223-3p.

CONCLUSION

MiR-223-3p suppressed NLRP3 inflamariomes activation, downstream inflammatory factors secretion and pyroptosis in LPS-induced HTR8/SVneo cells indicating that miR-223-3p could serve as an anti-inflammatory factor in preeclampsia.

PABPN1 regulates mRNA alternative polyadenylation to inhibit bladder cancer progression

BACKGROUND

About 10-20% of patients with bladder cancer (BC) progress to muscle-invasive diseases, of which the underlying key molecular events have yet to be addressed.

RESULTS

Here, we identified poly(A) binding protein nuclear 1 (PABPN1), a general factor of alternative polyadenylation (APA), was downregulated in BC. Overexpression and knockdown of PABPN1 significantly decreased and increased BC aggressiveness, respectively. Mechanistically, we provide evidence that the preference of PABPN1-bound polyadenylation signals (PASs) depends on the relative location between canonical and non-canonical PASs. PABPN1 shapes inputs converging on Wnt signaling, cell cycle, and lipid biosynthesis.

CONCLUSIONS

Together, these findings provide insights into how PABPN1-mediated APA regulation contributes to BC progression, and suggest that pharmacological targeting PABPN1 might have therapeutic potential in patients with BC.

LncRNA OIP5-AS1 reduces renal epithelial cell apoptosis in cisplatin-induced AKI by regulating the miR-144-5p/PKM2 axis

BACKGROUND

The abnormal expression of long non-coding RNA (lncRNA) Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1) has been observed in many human cancers and the underlying mechanisms have been well studied. However, the function of OIP5-AS1 in acute kidney injury (AKI) remains unclear.

METHODS

To explore the role of OIP5-AS1 in the progression of AKI, the cisplatin-induced AKI mouse and cell model were established. To confirm the potential protective effect of OIP5-AS1 during cisplatin-induced AKI, rescue experiments were performed. Targetscan was used to predict the potential targets of miR-144-5p. To further determine whether the effect of miR-144-5p during cisplatin-induced AKI was mediated by PMK2, the recuse experiments using PMK2 overexpressing vector was applied.

RESULTS

OIP5-AS1 was significantly downregulated both in cisplatin-induced AKI mice and human renal tubular cell line HK-2 cells. Moreover, overexpression of OIP5-AS1 efficiently promoted cell growth and reduced cisplatin-induced apoptosis of HK-2 cells. Furthermore, OIP5-AS1 was identified as a sponge of miR-144-5p, and upregulation of miR-144-5p could significantly reverse overexpression of OIP5-AS1-induced protective effect on the damage of cisplatin to HK-2 cells. In addition, pyruvate kinase M2 (PKM2) was found to be a direct target of miR-144-5p, and overexpression of PKM2 efficiently reversed the effect of miR-144-5p mimics on the damage in cisplatin-stimulated HK-2 cells.

CONCLUSIONS

OIP5-AS1 reduced the apoptosis of cisplatin-stimulated renal epithelial cells by targeting the miR-144-5p/PKM2 axis, which extended the regulatory network of lncRNAs in cisplatin-induced AKI and also provided a novel therapeutic target for AKI treatment.

Development and Validation of Prognostic Model in Transitional Bladder Cancer Based on Inflammatory Response-Associated Genes

Background

Bladder cancer is a common malignant type in the world, and over 90% are transitional cell carcinoma. While the impact of inflammatory response on cancer progression has been reported, the role of inflammatory response-associated genes (IRAGs) in transitional bladder cancer still needs to be understood.

Methods

In this study, IRAGs were download from Molecular Signature Database (MSigDB). The transcriptional expression and matched clinicopathological data were separately obtained from public databases. The TCGA-BLCA cohort was used to identify the differentially expressed IRAGs, and prognostic IRAGs were filtrated by univariate survival analysis. The intersection between them was displayed by Venn diagram. Based on least absolute shrinkage and selection operator (LASSO) regression analysis method, the TCGA-BLCA cohort was used to construct a risk signature. Survival analysis was conducted to calculate the overall survival (OS) in TCGA and GSE13507 cohort between two groups. We then conducted univariate and multivariate survival analyses to identify independently significant indicators for prognosis. Relationships between the risk scores and age, grade, stage, immune cell infiltration, immune function, and drug sensitivity were demonstrated by correlation analysis. The expression level of prognostic genes in vivo and in vitro were determined by qRT-PCR assay.

Results

Comparing with normal tissues, there were 49 differentially expressed IRAGs in cancer tissues, and 12 of them were markedly related to the prognosis in TCGA cohort for transitional bladder cancer patients. Based on LASSO regression analysis, a risk model consists of 10 IRAGs was established. Comparing with high-risk groups, survival analysis showed that patients in low-risk groups were more likely to have a better survival time in TCGA and GSE13507 cohorts. Besides, the accuracy of the model in predicting prognosis is acceptable, which is demonstrated by receiver operating characteristic curve (ROC) analysis. Age, stage, and risk scores variables were identified as the independently significant indicators for survival in transitional bladder cancer. Correlation analysis represented that the risk score was identified to be significantly related to the above variables except gender variable. Moreover, the expression level of prognostic genes in vivo and in vitro was markedly upregulated for transitional bladder cancer.

Conclusions

A novel model based on the 10 IRAGs that can be used to predict survival time for transitional bladder cancer. In addition, this study may provide treatment strategies according to the drug sensitivity in the future.

A Pilot Study of miRNA Expression Profile as a Liquid Biopsy for Full-Marathon Participants

Exosomal microRNA (miRNA) in plasma and urine has attracted attention as a novel diagnostic tool for pathological conditions. However, the mechanisms of miRNA dynamics in the exercise physiology field are not well understood in terms of monitoring sports performance. This pilot study aimed to reveal the miRNA dynamics in urine and plasma of full-marathon participants. Plasma and urine samples were collected from 26 marathon participants before, immediately after, 2 h after, and one day after a full marathon. The samples were pooled, and exosomal miRNAs were extracted and analyzed using next-generation sequencing. We determined that the exosomal miRNA expression profile changed under time dependency in full marathon. New uncharacterized exosomal miRNAs such as hsa-miR-582-3p and hsa-miR-199a-3p could be potential biomarkers reflecting physical stress of full marathon in plasma and urine. In addition, some muscle miRNAs in plasma and urine have supported the utility for monitoring physical stress. Furthermore, some inflammation-related exosomal miRNAs were useful only in plasma. These results suggest that these exosomal miRNAs in plasma and/or urine are highly sensitive biomarkers for physical stress in full marathons. Thus, our findings may yield valuable insights into exercise physiology.

Anti-apoptotic Effect of MiR-223-3p Suppressing PIK3C2A in Cardiomyocytes from Myocardial Infarction Rat Through Regulating PI3K/Akt Signaling Pathway

We aimed to explore the regulatory mechanism of the axis of miR-223-3p-PIK3C2A-PI3K/Akt on cardiomyocyte apoptosis in rats with myocardial infarction. Thirty 8-week-old healthy male SD rats were used for establishing the sham group and the model group, with HE staining, TUNEL staining, and TTC staining performed. After the identification of the targeting relationship between PIK3C2A and miR-223-3p, experimental rats were randomly divided into seven groups by plasmid transfection, including the Blank group, negative control (NC) group, miR-223-3p mimic group, miR-223-3p inhibitor group, siRNA-PIK3C2A group, oe-PIK3C2A group, and miR-223-3p inhibitor + oe-PIK3C2A group. Four weeks after transfection, the expression levels of miR-223-3p and PIK3C2A in tissues as well as PI3K, Akt, Bax, and bcl-2 mRNA in cells were detected by qRT-PCR and western blot, in combination with the detection of apoptosis rate by flow cytometry. Compared with the sham group, the model group showed typical myocardial injury and abnormal staining, higher apoptotic index, and larger myocardial infarction area (all P < 0.05). PIK3C2A was the target gene of miR-223-3p. The expression level of miR-223-3p in model group was significantly lower than that in sham group, while the mRNA and protein expression levels of PIK3C2A increased significantly (all P < 0.05). In cell tests, the expression level of miR-223-3p increased significantly in miR-223-3p mimic group (P < 0.05), which, however, showed no significant change in siRNA-PIK3C2A group (P > 0.05). MiR-223-3p inhibitor group and siRNA-PIK3C2A group had obviously increased PI3K, Akt, mTOR and Bcl-2 mRNA, and protein expression, while decreased mRNA and protein expression of PIK3C2A and Bax (all P < 0.05); miR-223-3p mimic groups had the opposite trends (all P < 0.05). siRNA-PIK3C2A + miR-223-3p mimic showed no obvious change relative to the control groups (all P > 0.05). Low expression of miR-223-3p may downregulate PIK3C2A expression, resulting in the inhibition of myocardial cell apoptosis in rats with myocardial infarction via the activation of PI3K/Akt signaling pathway.

miR-223-5p Suppresses OTX1 to Mediate Malignant Progression of Lung Squamous Cell Carcinoma Cells

BACKGROUND

Lung squamous cell carcinoma (LUSC) features high morbidity and mortality as a worldwide malignant tumor. This study mainly explored a miR-223-5p-dependent mechanism that affected proliferation, invasion, and migration of LUSC cells.

METHODS

Expression data of mature miRNAs and sequencing data of total RNA of LUSC were downloaded from TCGA database. Differentially expressed mRNAs were obtained. Function of miR-223-5p in LUSC cells was detected by assays like qRT-PCR, MTT, wound healing assay, Western blot, and Transwell assay. Western blot was performed to analyze the relationship between OTX1 and JAK/STAT signaling pathways. Dual-luciferase assay detected the relationship between miR-223-5p and OTX1. The way how miR-223-5p regulated LUSC cell biological functions via OTX1 was further explored.

RESULTS

It was noted that miR-223-5p expression in LUSC tissue and cells was significantly reduced. Overexpression of miR-223-5p negatively regulated the proliferation, invasion, and migration of LUSC cells. The downstream target gene OTX1 was detected to be notably elevated in LUSC cells. A negative correlation between OTX1 and miR-223-5p was also found. As analyzed by GSEA, OTX1 was significantly enriched in the JAK/STAT signaling pathway and activated the pathway. Dual-luciferase assay demonstrated that OTX1 was a direct molecular target of miR-223-5p in LUSC cells. Rescue experiment verified that miR-223-5p regulated the malignant phenotypes of LUSC cells by pairing with OTX1.

CONCLUSION

This study indicated that miR-223-5p was lowly expressed in LUSC cells. The impact of miR-223-5p on cell proliferation, invasion, and migration was realized by targeting OTX1. It is likely that miR-223-5p can be a novel target for LUSC treatment, which provides new ideas for future LUSC treatment.

LncRNA SLCO4A1-AS1 modulates colon cancer stem cell properties by binding to miR-150-3p and positively regulating SLCO4A1

Long non-coding RNAs (lncRNAs) play important roles in a range of different human cancers. However, the role of lncRNA solute carrier organic anion transporter family member 4A1-AS1 (SLCO4A1-AS1) in colon cancer remains enigmatic. Hence, we aimed to explore the specific role of SLCO4A1-AS1 in colon cancer stem cells. Colon cancer-related differentially expressed lncRNA and mRNA were screened using microarray-based analysis, and the expression of SLCO4A1-AS1 and SLCO4A1 in colon cancer tissues was determined using reverse transcription quantitative polymerase chain reaction and western blot analysis. The interaction among SLCO4A1-AS1, microRNA-150-3p (miR-150-3p) and SLCO4A1 was verified using dual-luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Moreover, SLCO4A1-AS1, miR-150-3p and/or SLCO4A1 were overexpressed or depleted in colon cancer cells to detect their effects on migration, invasion, sphere formation, apoptosis and tumorigenesis abilities of colon cancer stem CD133+CD44+ cells using both in vitro and in vivo assays. SLCO4A1-AS1 and SLCO4A1 were screened as the differentially expressed lncRNA and mRNA in colon cancer tissues. SLCO4A1-AS1 was confirmed to competitively bind to miR-150-3p to elevate SLCO4A1 expression. Moreover, knockdown of SLCO4A1-AS1 decreased SLCO4A1 expression, thus inhibiting cell migration, invasion, sphere formation, and tumorigenesis abilities and enhancing the apoptosis of CD133+CD44+ cells. Collectively, these findings provide evidence demonstrating that depleting SLCO4A1-AS1 competitively binds to miR-150-3p, which downregulates SLCO4A1 expression, thus hindering colon cancer progression.

Differentially Expressed Extracellular Vesicle-Contained microRNAs before and after Transurethral Resection of Bladder Tumors

Bladder cancer (BC) is currently diagnosed and monitored by cystoscopy, a costly and invasive procedure. Potential biomarkers in urine, blood, and, more recently, extracellular vesicles (EVs), have been explored as non-invasive alternatives for diagnosis and surveillance of BC. EVs are nanovesicles secreted by most cell types containing diverse molecular cargo, including different types of small RNAs, such as microRNA (miRNA). In this study, we performed next-generation sequencing of EV-contained miRNA isolated from urine and serum of 41 patients with non-muscle invasive BC (27 stage Ta, 14 stage T1) and 15 non-cancer patients (NCP) with benign cystoscopy findings. MiRNA sequencing was also performed on serum supernatant samples for T1 patients. To identify potential BC-specific biomarkers, expression levels of miRNA in presurgery samples were compared to those at postsurgery check-ups, and to NCPs. Results showed that two miRNAs, urinary EV-contained miR-451a and miR-486-5p, were significantly upregulated in presurgery samples from T1 patients compared to postsurgery check-up samples. This was confirmed in a replica EV/RNA isolation and sequencing run of 10 T1 patients from the primary run; however, analyses revealed no differential expression of miRNAs in serum EVs, serum supernatant, or when comparing BC patients to NCPs. This is the first study to investigate EV-containing miRNA sequencing in pre- and postsurgery BC patient samples and our findings suggest that urinary EV-contained miR-451a and miR-486-5p may be potential biomarkers for recurrence-free survival of BC patients with stage T1 disease.

CDCA2 protects against oxidative stress by promoting BRCA1-NRF2 signaling in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) patients mostly suffer from poor survival outcomes. It is necessary to identify effective therapeutic targets to improve prognosis for HCC patients. Here, we report a new factor, CDCA2, in promoting HCC development. CDCA2 amplification is an independent risk factor for the recurrence and survival of HCC patients, which is positively correlated with elevated level of alpha-fetoprotein (AFP), high histological grade, large tumor size, advanced TNM stage, and poor prognosis for HCC patients. In HCC cells, CDCA2 promotes cell growth and inhibits apoptosis. Mechanistically, CDCA2's transcription is activated through the binding of E2F2/E2F8 with its promoter. CDCA2 depletion contributes to the suppression of cell proliferation and induction of apoptosis due to reactive oxygen species (ROS)-mediated stress, which can be reversed by antioxidants N-acetyl cysteine (NAC) and glutathione (GSH). Interestingly, we found that CDCA2 triggers the BRCA1-NRF2 cascade, which elevates antioxidant response and attenuates ROS levels. In response to oxidative stress, CDCA2 promotes BRCA1's chromatin relocalization to NRF2, activating NRF2-driven downstream signaling (HO-1, TXNRD1, and NQO1), which then protects HCC cells against oxidative damage. In conclusion, our results reveal that CDCA2 is a prognostic biomarker for HCC patients, and present the E2F2/E2F8-CDCA2-BRCA1-NRF2-ROS signaling axis that have implications for HCC therapeutics.

Emerging Biomarkers for Predicting Bladder Cancer Lymph Node Metastasis

Bladder cancer is one of the leading causes of cancer deaths worldwide. Early detection of lymph node metastasis of bladder cancer is essential to improve patients' prognosis and overall survival. Current diagnostic methods are limited, so there is an urgent need for new specific biomarkers. Non-coding RNA and m6A have recently been reported to be abnormally expressed in bladder cancer related to lymph node metastasis. In this review, we tried to summarize the latest knowledge about biomarkers, which predict lymph node metastasis in bladder cancer and their mechanisms. In particular, we paid attention to the impact of non-coding RNA on lymphatic metastasis of bladder cancer and its specific molecular mechanisms, as well as some prediction models based on imaging, pathology, and biomolecules, in an effort to find more accurate diagnostic methods for future clinical application.

MicroRNA-223-5p suppresses the progression of nasopharyngeal carcinoma by targeting DCLK1

The aim of the present study was to investigate the function of microRNA (miR)-223-5p in the malignant biological behavior of nasopharyngeal carcinoma (NPC) and elucidate the underlying molecular mechanism. The expression levels of miR-223-5p and doublecortin-like kinase 1 (DCLK1) were detected via reverse transcription-quantitative PCR analysis. Cell viability was evaluated using Cell Counting Kit-8 assay. Cell migration and invasion were measured via Transwell assays, while a luciferase reporter assay was conducted to identify the interaction between miR-223-5p and DCLK1. The results demonstrated that miR-223-5p expression was significantly downregulated, whereas DCLK1 expression was significantly upregulated in NPC tissues and cells. Moreover, both miR-223-5p overexpression and DCLK1 silencing markedly suppressed the progression of NPC. It was also observed that miR-223-5p directly targeted DCLK1 and decreased its expression. Furthermore, it was suggested that DCLK1 overexpression may partially reverse the suppressive effects of miR-223-5p on the progression of NPC. Collectively, the results of the present study indicated that miR-223-5p may suppress NPC progression by targeting DCLK1, thereby indicating a novel potential approach to the diagnosis and treatment of NPC.

Anti-Tumor Effect of Celastrol on Hepatocellular Carcinoma by the circ_SLIT3/miR-223-3p/CXCR4 Axis

Background

Celastrol is a potential anti-tumor agent in hepatocellular carcinoma (HCC). Identifying the molecular determinants of the anti-HCC effect of celastrol is still challenging. In this study, we undertook to associate circular RNAs (circRNAs) with the anti-HCC molecular determinants of celastrol.

Methods

Cell colony formation, proliferation, migration, invasion and apoptosis were determined using the colony formation, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTS), transwell and flow cytometry assays, respectively. The levels of circRNA slit guidance ligand 3 (circ_SLIT3), miR-223-3p and C-X-C motif chemokine receptor 4 (CXCR4) were gauged by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Ribonuclease R (RNase R) and actinomycin D assays were performed to assess the stability of circ_SLIT3. Targeted relationships among circ_SLIT3, miR-223-3p and CXCR4 were confirmed by the dual-luciferase reporter assay. In vivo assays were performed to detect the roles of celastrol and circ_SLIT3 on tumor growth in vivo.

Results

Celastrol repressed HCC cell proliferation, migration, invasion, and enhanced apoptosis in vitro and suppressed tumor growth in vivo. Celastrol down-regulated circ_SLIT3 expression in HCC cells, and celastrol exerted an anti-tumor effect on HCC in vitro and in vivo by down-regulating circ_SLIT3. Mechanistically, circ_SLIT3 directly interacted with miR-223-3p, and circ_SLIT3 controlled CXCR4 expression by sponging miR-223-3p. Moreover, miR-223-3p was involved in the celastrol/circ_SLIT3-mediated regulation on HCC progression. Furthermore, celastrol exerted the anti-HCC effect in vitro through the miR-223-3p/CXCR4 axis.

Conclusion

Our present work first identified the circ_SLIT3/miR-223-3p/CXCR4 axis as a novel mechanism of the anti-HCC effect of celastrol, providing a new insight into the involvement of circRNAs in the anti-tumor molecular determinants of celastrol.

MicroRNA‑149‑3p inhibits cell proliferation by targeting AKT2 in oral squamous cell carcinoma

MicroRNAs (miRs) exhibit oncogenic or tumor suppressive functions that contribute to the initiation and development of various types of human cancer. miR-149-3p has been reported to serve multiple roles in the regulation of proliferation, apoptosis and metastasis. However, the effects and detailed mechanism of miR-149-3p in oral squamous cell carcinoma (OSCC) remain unclear. In the present study, miR-149-3p mimic, mimic control, miR-149-3p inhibitor and inhibitor control were transiently transfected into Cal27 and SCC-9 cells. The viability, proliferation and apoptosis of OSCC cells were determined using Cell Counting Kit-8, colony formation and Annexin V assays, respectively. The mRNA expression levels of miR-149-3p and AKT2 were determined by reverse transcription-quantitative PCR. The protein expression levels of AKT2, cleaved caspase-3 and cleaved PARP were examined by western blot analysis. The binding of miR-149-3p to the AKT2 3′-untranslated region was evaluated by a dual luciferase reporter assay. In the present study, overexpression of miR-149-3p reduced the viability and proliferation of OSCC cells. By contrast, increased cell viability and proliferation was observed in miR-149-3p-deficient OSCC cells. Dual luciferase reporter assay indicated that miR-149-3p significantly decreased the luciferase activity of the wild-type AKT2 3′-untranslated region. Moreover, overexpression of miR-149-3p downregulated the mRNA and protein expression levels of AKT2, suggesting that miR-149-3p was a negative modulator of AKT2. Restoration of AKT2 efficiently reversed the miR-149-3p-mediated reduction in the proliferative capacity of OSCC cells. In addition, miR-149-3p enhanced the sensitivity of OSCC cells to the chemotherapeutic drug 5-fluorouracil. Taken together, the current findings revealed an inhibitory effect of miR-149-3p on the proliferation of OSCC cells through the post-transcriptional suppression of AKT2, and indicated a potential chemosensitizing function of miR-149-3p for the treatment of patients with OSCC.

Extracellular miRNAs for the Management of Barrett's Esophagus and Esophageal Adenocarcinoma: A Systematic Review

Esophageal adenocarcinoma (EAC), the major histologic type of esophageal cancer (EC) in Western countries, is a disease with a poor prognosis, primarily due to usual diagnosis at an advanced stage. The prevalence of EAC has increased in recent years, both in Western countries and in Asia. Barrett's esophagus (BE) is a precursor lesion of EAC. Therefore, early detection and proper management of BE and EAC is important to improve prognosis. Here, we systematically summarize current knowledge about the potential utility of extracellular microRNAs (miRNAs), which are thought to be non-invasive biomarkers for many diseases, for these purposes. A search of the PubMed and Embase databases identified 22 papers about extracellular miRNAs that have potential utility for management of EAC. Among them, 19 were EAC-related and ten were BE-related; some of these dealt with both conditions. The articles included studies reporting diagnosis, prognosis, and treatment responses. Multiple papers report dysregulation of miR-194-5p in BE and miR-21-5p, -25-3p, and -93-5p in EAC. Although it will take time to utilize these miRNAs in clinical practice, they are likely to be useful non-invasive markers in the future.

MicroRNAs and target molecules in bladder cancer

Bladder cancer (BC) is considered as one of the most common malignant tumors in humans with complex pathogenesis including gene expression variation, protein degradation, and changes in signaling pathways. Many studies on involved miRNAs in BC have demonstrated that they could be used as potential biomarkers in the prognosis, response to treatment, and screening before the cancerous phenotype onset. MicroRNAs (miRNAs) regulate many cellular processes through their different effects on special targets along with modifying signaling pathways, apoptosis, cell growth, and differentiation. The diverse expression of miRNAs in cancerous tissues could mediate procedures leading to the oncogenic or suppressor behavior of certain genes in cancer cells. Since a specific miRNA may have multiple targets, an mRNA could also be regulated by multiple miRNAs which further demonstrates the actual role of miRNAs in cancer. In addition, miRNAs can be utilized as biomarkers in some cancers that cannot be screened in the early stages. Hence, finding blood, urine, or tissue miRNA biomarkers by novel or routine gene expression method could be an essential step in the prognosis and control of cancer. In the present review, we have thoroughly evaluated the recent findings on different miRNAs in BC which can provide comprehensive information on better understanding the role of diverse miRNAs and better decision making regarding the new approaches in the diagnosis, prognosis, prevention, and treatment of BC.

Serum exosomal microRNA transcriptome profiling in subacute spinal cord injured rats

MicroRNAs (miRNAs) are involved in a series of pathology of spinal cord injury (SCI). Although, locally expressed miRNAs have advantages in studying the pathological mechanism, they cannot be used as biomarkers. The "free circulation" miRNAs can be used as biomarkers, but they have low concentration and poor stability in body fluids. Exosomal miRNAs in body fluids have many advantages comparing with free miRNAs. Therefore, we hypothesized that the specific miRNAs in the central nervous system might be transported to the peripheral circulation and concentrated in exosomes after injury. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and subactue SCI rats were analyzed. The results showed that SCI can lead to changes of serum exosomal miRNAs. These changed miRNAs and their associated signaling pathways may explain the pathological mechanism of suacute SCI. More importantly, we found some valuable serum exosomal miRNAs for diagnosis and prognosis of SCI.

Regulation of aberrantly expressed SERPINH1 by antitumor miR-148a-5p inhibits cancer cell aggressiveness in gastric cancer

RNA-sequencing-based microRNA (miRNA) expression signatures have revealed that miR-148a-5p (the passenger strand of the miR-148a-duplex) is downregulated in various kinds of cancer tissues. Analysis of The Cancer Genome Atlas (TCGA) database showed that low expression of miR-148a-5p was predictive of a lower survival rate (p = 0.041) in patients with gastric cancer (GC). Downregulation of miR-148a-5p was confirmed in GC clinical specimens, and its ectopic expression attenuated GC cell proliferation. Our search for miRNA target genes identified a total of 18 oncogenic targets of miR-148a-5p in GC cells. Among these targets, high expression levels of six genes (THBS2, P4HA3, SERPINH1, CDH11, BCAT1, and KCNG3) were closely associated with a poor prognosis (10-year survival rates) in GC patients (p < 0.05) according to TCGA database analyses. Furthermore, we focused on SERPINH1 as a chaperone protein involved in collagen folding in humans. Aberrant expression of SERPINH1 (mRNA and protein levels) was confirmed in GC clinical specimens. Knockdown assays of SERPINH1 using siRNAs resulted in inhibition of the aggressive phenotype of GC cells. Exploring the molecular networks controlled by miRNAs (including miRNA passenger strands) will broaden our understanding of the molecular pathogenesis of GC.

Inhibition of miR-223 attenuates the NLRP3 inflammasome activation, fibrosis, and apoptosis in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is an independent and specific cardiomyopathy, which is associated with cardiac failure in diabetic patients. Currently, the pathogenesis of DCM is a popular research topic in the investigation of cardiovascular diseases. MicroRNAs (miRNAs) have been identified as the latent therapeutic targets for DCM. However, the functions and complex mechanisms of miRNAs in DCM have not been clarified. The cardiomyocyte injury model was established using high glucose (HG) ingestion, and the DCM rat model was established using 30 mg/kg streptozotocin. MicroRNA-223 (miR-223) expression was determined using qRT-PCR; the levels of NLRP3 inflammasome, fibrosis, and apoptosis-related genes and proteins were analyzed using qRT-PCR and western blot assays. Besides the morphological changes and fibrosis of myocardial tissues were evaluated using H&E and Masson staining. We discovered that miR-223 was highly expressed in the HG-induced cardiomyocyte injury model, and miR-223 inhibitor could further relieve the myocardial fibrosis and apoptosis, and inhibit NLRP3 inflammasome of HG-induced H9c2 cells. Additionally, we found that inhibition of miR-223 had obvious positive effects on the cardiac dysfunction and reduced the elevation of blood sugar in the DCM model rats. We found that the miRNA-223 inhibitor could improve the morphological structure and the degree of fibrosis in myocardial tissues in the DCM model rats. Moreover, we verified that inhibition of miR-223 could suppress the NLRP3 inflammasome activation, and alleviate myocardial fibrosis and apoptosis of the DCM model rats. In conclusion, our results suggested that miR-223 might be an underlying therapeutic target for DCM by reducing NLRP3 inflammasome activation, fibrosis, and apoptosis.

MiR-223-3p regulates cell viability, migration, invasion, and apoptosis of non-small cell lung cancer cells by targeting RHOB

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer with a high fatality rate in men and women worldwide. Recently, microRNAs (miRNAs) have been reported to be diagnostic biomarkers and therapeutic targets in NSCLC. MiR-223-3p was proved to act as a promoter in NSCLC progression. However, the regulatory mechanism of miR-223-3p in NSCLC remains little known. This study aimed to explore the regulatory mechanism between miR-223-3p and its target gene Ras homolog family member B (RHOB) in NSCLC. The mRNA level of miR-223-3p and RHOB was measured by quantitative reverse transcription PCR. Furthermore, cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry was conducted to analyze cell apoptosis. Transwell assays and wound healing assay were employed to examine migration and invasion. The target relationship between miR-223-3p and RHOB was predicted by starBase online database and verified by dual-luciferase assay. The protein level of RHOB was tested by western blot. Our data suggested that miR-223-3p was upregulated in NSCLC tissues and cell lines and high level of miR-223-3p contributed to a poor survival in NSCLC patients. Knockdown of miR-223-3p exerted inhibitory effects on NSCLC cell viability, migration, and invasion and promotion effect on cell apoptosis. Furthermore, RHOB was directly targeted by miR-223-3p and constrained NSCLC progression. Moreover, knockdown of RHOB rescued the effect of anti-miR-223-3p on NSCLC progression. In vivo experiments indicated that miR-223-3p deletion suppressed tumor growth. MiR-223-3p could regulate the NSCLC cellular processes through targeting RHOB.

miR-223-5p targeting ERG inhibits prostate cancer cell proliferation and migration

Ectopic expression of miR-223-5p, the lagging strand of miR-223 duplex, has been reported acting as anti-tumor miRNA in many cancers. How miR-223-5p influencing prostate cancer (PCa) remains obscure and worth of experimental investigation. In this study, the expressions of miR-223-5p and ERG in common PCa cell lines were detected and compared to RWPE-1, respectively. Then luciferase reporter assay was performed to verify whether miR-223-5p could specifically target and regulate ERG. Further discovery ERG's role in the PCa oncogenesis was also conducted by up or down regulating miR-223-3p expression. We found miR-223-5p was significantly down-regulated in DU145, while it was only up-regulated in LNCaP. Similarly, ERG expression remarkably decreased in both PC-3 and DU145 than that in RWPE-1, but significantly increasing in LNCaP. Luciferase assay demonstrated slightly decreased ERG expression after miR-223-5p-mimics but significantly increased ERG expression after miR-223-5p-inhibtor. Using gene interference, we further confirmed that both ERG mRNA and protein expressions were decreased in all PCa lines transfected ERG siRNA, but increasing in both DU145 and LNCaP cells with miR-223-5p antisense oligonucleotides. MTT assay, Transwell invasion and migration assay supported the function of ERG in PCa oncogenesis. We revealed tumor suppressive abilities of miR-223-5p in PCa by negatively targeting ERG gene. It could serve as a fundamental supplement and extension of our previous study about miR-223-3p in PCa, revealing the coordinative regulation between miR-223-5p and miR-223-3p in PCa cell biological behaviors. Exploration of miR-233-duplex orientated pathway networks may help us develop novel potential therapeutic options for PCa.

Knockdown of CDCA8 inhibits the proliferation and enhances the apoptosis of bladder cancer cells

Bladder cancer is a tumour of the urinary system with high mortality, and there is also a great lack of therapeutic targets in the clinic. Cell division cycle associated 8 (CDCA8), an important component of the vertebrate chromosomal passenger complex, is highly expressed in various tumours and promotes tumour development. However, the role of CDCA8 in bladder cancer is not fully understood. This study aimed to reveal the function of CDCA8 in bladder cancer by determining the relationship between CDCA8 expression and proliferation, metastasis and apoptosis of bladder cancer cells. Firstly, we studied the mRNA expression of CDCA8 through the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) databases and analysed the correlation between CDCA8 expression and prognosis of patients with bladder cancer. We also verified CDCA8 expression in bladder cancer tissues by immunohistochemistry. In addition, CDCA8 expression was inhibited in bladder cancer T24 and 5637 cells, and the effects of CDCA8 on the proliferation, migration and invasion of bladder cancer cell lines were investigated using cell counting kit-8, colony formation, cell cycle, apoptosis, wound healing and Transwell invasion assays. Results showed that CDCA8 was highly expressed in bladder cancer compared with normal tissues, and the high CDCA8 expression was significantly correlated with the poor prognosis of patients. Inhibiting CDCA8 expression inhibited the proliferation, migration and invasion of T24 and 5637 cells and induced the apoptosis of bladder cancer cells. CDCA8 was involved in the regulation of the growth cycle of bladder cancer cells. Bioinformatics-based mechanism analysis revealed that high CDCA8 expression may affect the cell cycle and P53 signalling pathways. In conclusion, our results suggest that CDCA8 is highly expressed in bladder cancer and can promote tumour development. Hence, CDCA8 may serve as an effective therapeutic target for treatment of bladder cancer.

miR-223-3p promotes cell proliferation and invasion by targeting Arid1a in gastric cancer

Accumulating evidence has indicated that microRNAs can regulate downstream signaling pathways and play an important role in various tumors. In this study, we found that miR-223-3p was differentially expressed in 40 paired gastric cancer tissues and adjacent tissues and that miR-223-3p was positively correlated with tumor invasion depth and lymph node metastasis. Luciferase reporter assay confirmed that Arid1a was the target gene of miR-223-3p. Functional assays showed that miR-223-3p promoted the proliferation and invasion of gastric cancer cells by regulating the expression of Arid1a. We also confirmed that miR-223-3p regulated the growth of gastric cancer cells in vivo, while an antagomir against miR-223-3p significantly inhibited tumor growth. In conclusion, our results demonstrated that miR-223-3p inhibits gastric cancer cell progression by decreasing the expression of Arid1a. Therefore, miR-223-3p may act as a potential therapeutic target for patients with gastric cancer.

Serum exosomal microRNA transcriptome profiling in subacute spinal cord injured rats

MicroRNAs (miRNAs) are involved in a series of pathology of spinal cord injury (SCI). Although, locally expressed miRNAs have advantages in studying the pathological mechanism, they cannot be used as biomarkers. The "free circulation" miRNAs can be used as biomarkers, but they have low concentration and poor stability in body fluids. Exosomal miRNAs in body fluids have many advantages comparing with free miRNAs. Therefore, we hypothesized that the specific miRNAs in the central nervous system might be transported to the peripheral circulation and concentrated in exosomes after injury. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and subactue SCI rats were analyzed. The results showed that SCI can lead to changes of serum exosomal miRNAs. These changed miRNAs and their associated signaling pathways may explain the pathological mechanism of suacute SCI. More importantly, we found some valuable serum exosomal miRNAs for diagnosis and prognosis of SCI.

Long noncoding RNA DLX6-AS1 promotes cell growth and invasiveness in bladder cancer via modulating the miR-223-HSP90B1 axis

Long noncoding RNA (lncRNA) regulate many biological processes ranging from tumorigenesis to cancer metastasis. MicroRNA-223 (miR-223) acts as a novel tumor suppressor in bladder cancer (BC), however its target genes involved in BC, the molecular mechanisms governing its expression remain largely unknown. Both gain-of-function and loss of function experiments were performed to investigate the role of miR-223 in BC cells. The effects of miR-223 on BC progression were assessed using in vivo subcutaneous xenografts. The luciferase reporter assays were utilized to confirm the putative miR-223-binding site in the 3'-UTR of oncogene HSP90B1. The luciferase reporter assays and RNA immunoprecipitation assays were used to analyze the association between miR-223 and lncRNA DXL6-AS1 in BC cells. The expression of miR-223 was remarkably decreased in BC samples and BC cells. High miR-223 expression was correlated with favorable patient survival. BC cell growth in vivo was delayed by miR-223 overexpression. HSP90B1 was a direct target of miR-223 in BC cells, and the suppression of BC cell growth and invasion induced by miR-223 could be rescued by overexpression of HSP90B1. Moreover, lncRNA DXL6-AS1 was upregulated in BC tissues and functioned as a sponge for miR-223 and reduced its expression in BC cells, thereby enhancing cell proliferation and invasion. Forced expression of miR-223 could reverse the oncogenic effects of DXL6-AS1 on BC cell proliferation and invasion. Our study suggested that DLX6-AS1-mediated silencing of miR-223 promotes BC progression through the upregulation of HSP90B1.

MicroRNA-223-3p modulates dendritic cell function and ameliorates experimental autoimmune myocarditis by targeting the NLRP3 inflammasome

Autoimmune myocarditis is a cause of dilated cardiomyopathy and heart failure. MicroRNAs regulate many immune processes, but their role in aberrant inflammation during autoimmune myocarditis remains unclear. In this study, we investigated the role of miR-223-3p in experimental autoimmune myocarditis (EAM). We found that miR-223-3p expression was significantly lower in EAM mice than that in normal mice. miR-223-3p inhibited NLRP3 inflammasome expression, promoting the polarization of dendritic cells (DCs) towards a tolerogenic DC phenotype. miR-223-3p effectively induced regulatory T cell (Treg) generation by inhibiting the function of antigen-presenting DCs. Transfer of miR-223-3p-overexpressing DCs protected mice against the development of EAM. Our findings suggest that miR-223-3p is involved in the induction of the tolerogenic DC phenotype and regulates tolerance in autoimmune myocarditis.

Assessment by miRNA microarray of an autologous cancer antigen-pulsed adoptive immune ensemble cell therapy (AC-ACT) approach; demonstrated induction of anti-oncogenic and anti-PD-L1 miRNAs

A 60-year-old woman with stage IV rectal cancer received adoptive cell therapy with autologous cancer antigen (AC-ACT) causing induction of anti-oncogenic and anti-PD-L1 miRNAs as assessed by miRNA microarray. More than 1 year after AC-ACT, metastases have been arrested, and the patient reports good quality of life.

Polyunsaturated fatty acids modulate the delivery of platelet microvesicle-derived microRNAs into human breast cancer cell lines

Breast cancer is one of the most frequent and malignant types of cancer in women, with an increasing morbidity and mortality rate; in particular, treatment of triple negative breast cancer remains a challenge, since the efforts made with targeted therapies were ineffective. Among surrounding cells influencing the biology of cancer cells, platelets are recognizing as novel players. Activated platelets release microvesicles (MVs) that, once delivered to cancer cells, modulate signaling pathways related to cell growth and dissemination; among factors contained in platelet-derived MVs, microRNAs are highly involved in cancer development. The growing interest in ω3 and ω6 polyunsaturated fatty acids (PUFAs) as adjuvants in anti-cancer therapy prompted us to investigate the ability of arachidonic acid (AA) and docosahexaenoic acid (DHA) to modulate MV biological functions. AA induced differential enhancement of platelet-specific microRNAs (miR-223 and miR-126), an effect further enhanced by the presence of DHA. MVs can be delivered to and microRNAs internalized by breast cancer cells, although with different efficiency; analysis of kinetics of MV delivery, indeed, suggested that tumor cells fine-tune the uptake of specific microRNA. Finally, we demonstrated that physiological delivery of platelet miR-223 and miR-126 induced cellular effects in breast cancer cells, including cell cycle arrest, inhibition of migration and sensitivity to cisplatin. These results have been confirmed by exogenous expression of miR-223 and miR-126 through transient transfection experiments. Our preliminary data suggest that ω6/ω3-PUFA supplementation, by modulating microRNA delivery, enhances platelet anti-tumor activities, thus opening new avenues for add-on therapies in cancer patients.

Involvement of Dual Strands of miR-143 (miR-143-5p and miR-143-3p) and Their Target Oncogenes in the Molecular Pathogenesis of Lung Adenocarcinoma

Our analyses of tumor-suppressive microRNAs (miRNAs) and their target oncogenes have identified novel molecular networks in lung adenocarcinoma (LUAD). Moreover, our recent studies revealed that some passenger strands of miRNAs contribute to cancer cell malignant transformation. Downregulation of both strands of the miR-143 duplex was observed in LUAD clinical specimens. Ectopic expression of these miRNAs suppressed malignant phenotypes in cancer cells, suggesting that these miRNAs have tumor-suppressive activities in LUAD cells. Here, we evaluated miR-143-5p molecular networks in LUAD using genome-wide gene expression and miRNA database analyses. Twenty-two genes were identified as potential miR-143-5p-controlled genes in LUAD cells. Interestingly, the expression of 11 genes (MCM4, RAD51, FAM111B, CLGN, KRT80, GPC1, MTL5, NETO2, FANCA, MTFR1, and TTLL12) was a prognostic factor for the patients with LUAD. Furthermore, knockdown assays using siRNAs showed that downregulation of MCM4 suppressed cell growth, migration, and invasion in LUAD cells. Aberrant expression of MCM4 was confirmed in the clinical specimens of LUAD. Thus, we showed that miR-143-5p and its target genes were involved in the molecular pathogenesis of LUAD. Identification of tumor-suppressive miRNAs and their target oncogenes may be an effective strategy for elucidation of the molecular oncogenic networks of this disease.

MicroRNAs: Key Players in Bladder Cancer

Bladder cancer (BC) is the second highest morbid malignancy of the urinary tract and the fifth most common cancer worldwide. BC is highly malignant with significant morbidity and mortality, especially muscle-invasive BC (MIBC), which has a poor prognosis and frequently recurs after the first resection. Therefore, more sensitive diagnostic tools and effective therapeutic methods are urgently needed. MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of protein-coding genes by repressing their translation or cleaving RNA transcripts in a sequence-specific manner. miRNAs play very important roles in regulating genes related to tumorigenesis, tumor development, progression, metastasis and angiogenesis. With the rapid development of high-throughput sequencing technology, an increasing number of miRNAs with aberrant expression between either BC patients and healthy volunteers or between BC tumor tissues and matched peripheral control tissues have been recently examined. The tumor etiopathogenesis must be determined to promote the development of new markers as diagnostic and prognostic tools and targets for bladder tumor therapy, it is therefore vital to elucidate the function of miRNAs with aberrant expression in BC. In the present study, we examined the published data of BC-related miRNAs by reviewing their expression levels, possible functions, potential target genes, related molecular regulatory networks, candidate markers for prognosis and diagnosis, and prospective therapeutic cases, and we summarized the status of research on BC-related miRNAs in recent years.

Aberrantly expressed PLOD1 promotes cancer aggressiveness in bladder cancer: a potential prognostic marker and therapeutic target

Bladder cancer (BC) is the ninth most malignant tumor worldwide. Some BC patients will develop muscle‐invasive BC (MIBC), which has a 5‐year survival rate of approximately 60% due to metastasis. As such, there is an urgent need for novel therapeutic and diagnostic targets for MIBC. Analysis of novel antitumor microRNA (miRNA)‐mediated cancer networks is an effective strategy for exploring therapeutic targets and prognostic markers in cancers. Our previous miRNA analysis revealed that miR‐140‐5p acts as an antitumor miRNA in BC cells. Here, we investigated miR‐140‐5p regulation of BC molecular pathogenesis. Procollagen‐lysine, 2‐oxoglutarate 5‐dioxygenase 1 (PLOD1) was found to be directly regulated by miR‐140‐5p, and aberrant expression of PLOD1 was observed in BC clinical specimens. High PLOD1 expression was significantly associated with a poor prognosis (disease‐free survival: P = 0.0204; overall survival: P = 0.000174). Multivariate analysis showed PLOD1 expression to be an independent prognostic factor in BC patients (hazard ratio = 1.51, P = 0.0099). Furthermore, downregulation of PLOD1 by siRNAs and a specific inhibitor significantly decreased BC cell aggressiveness. Aberrant expression of PLOD1 was closely associated with BC pathogenesis. In summary, the present study showed that PLOD1 may be a potential prognostic marker and therapeutic target for BC.

Molecular Pathogenesis of Gene Regulation by the miR-150 Duplex: miR-150-3p Regulates TNS4 in Lung Adenocarcinoma

Based on our miRNA expression signatures, we focused on miR-150-5p (the guide strand) and miR-150-3p (the passenger strand) to investigate their functional significance in lung adenocarcinoma (LUAD). Downregulation of miR-150 duplex was confirmed in LUAD clinical specimens. In vitro assays revealed that ectopic expression of miR-150-5p and miR-150-3p inhibited cancer cell malignancy. We performed genome-wide gene expression analyses and in silico database searches to identify their oncogenic targets in LUAD cells. A total of 41 and 26 genes were identified as miR-150-5p and miR-150-3p targets, respectively, and they were closely involved in LUAD pathogenesis. Among the targets, we investigated the oncogenic roles of tensin 4 (TNS4) because high expression of TNS4 was strongly related to poorer prognosis of LUAD patients (disease-free survival: p = 0.0213 and overall survival: p = 0.0003). Expression of TNS4 was directly regulated by miR-150-3p in LUAD cells. Aberrant expression of TNS4 was detected in LUAD clinical specimens and its aberrant expression increased the aggressiveness of LUAD cells. Furthermore, we identified genes downstream from TNS4 that were associated with critical regulators of genomic stability. Our approach (discovery of anti-tumor miRNAs and their target RNAs for LUAD) will contribute to the elucidation of molecular networks involved in the malignant transformation of LUAD.

Hypoxia-elevated circELP3 contributes to bladder cancer progression and cisplatin resistance

Hypoxia plays a critical role in cancer biology. It induces genomic instability, which in turn helps cancer cells respond adaptively to meet the needs of carcinogenesis, cancer progression and relapse. Circular RNA has not been reported among the variety of downstream factors in this adaptive response. Although a few studies have demonstrated the important role of circular RNAs in driving human bladder cancer progression, their carcinogenic roles are still under investigated. Here, we identified a hypoxia-elevated circular RNA, circELP3, that contributes to bladder cancer progression and cisplatin resistance. Decreasing the level of circELP3 via siRNA clearly reduced the in vitro proliferation and cisplatin resistance of bladder cancer cells and promoted apoptosis. Interfering with circELP3 suppressed tumor xenograft growth in nude mice in vivo. In addition, lower circELP3-expressing bladder cancer cells displayed poorer self-renewal capacity, as demonstrated by lower levels of sphere formation and stem cell marker expression. Furthermore, in human bladder cancer patients, strong correlations between a high circELP3 level and advanced tumor grade and lymph node metastasis were observed. In summary, we provide the first direct evidence that circular RNA participates in the adaptive response to hypoxia and may play a role in the progression and drug resistance of bladder cancer.

MicroRNA‑223 promotes osteoblast differentiation of MC3T3‑E1 cells by targeting histone deacetylase 2

MicroRNAs (miRNAs) have emerged as pivotal regulators in various physiological and pathological processes at the post‑transcriptional level, and may serve important roles in osteogenic differentiation. However, their roles and functions are not fully understood. In the present study, miR‑223‑5p was identified as a modulator of osteoblastic differentiation in MC3T3‑E1 cells. Reverse transcription‑quantitative polymerase chain reaction and western blotting demonstrated that miR‑223‑5p was significantly upregulated in MC3T3‑E1 cells following the induction of osteoblast differentiation. Overexpression of miR‑223‑5p promoted osteogenic differentiation both in vitro and vivo. Expression of histone deacetylase 2 (HDAC2), which acts as a negative regulator of osteogenesis, was regulated by miR‑223‑5p. Collectively, the results of the present study revealed a novel miR‑223‑5p/HDAC2 axis that regulates osteoblast differentiation, and may serve as a potential target for enhancing bone formation in vivo.

Pirin: a potential novel therapeutic target for castration-resistant prostate cancer regulated by miR-455-5p

Androgen deprivation therapy is frequently used to treat prostate cancer (PCa), but resistance can occur, a condition known as castration‐resistant prostate cancer (CRPC). Thus, novel approaches for identification of CRPC are important for designing effective PCa treatments. Analysis of microRNA (miRNA) expression signatures by RNA sequencing showed that both passenger and guide strands of the miR‐455‐duplex (miR‐455‐5p and miR‐455‐3p, respectively) acted as antitumor miRNAs in PCa cells. The involvement of miRNA passenger strands in cancer pathogenesis is a novel concept for miRNA functionality. Based on a large patient cohort in The Cancer Genome Atlas, expression of eight miR‐455‐5p/‐3p target genes (PIR: P = 0.0137, LRP8: P = 0.0495, IGFBP3: P = 0.0172, DMBX1: P = 0.0175, CCDC64: P = 0.0446, TUBB1: P = 0.0149, KIF21B: P = 0.0336, and NFAM1: P = 0.0013) was significantly associated with poor prognosis of PCa patients. Here, we focused on PIR (pirin), a highly conserved member of the cupin superfamily. PIR expression was directly regulated by miR‐455‐5p, and PIR overexpression was detected in hormone‐sensitive prostate cancer (HSPC) surgical specimens and CRPC autopsy specimens. Loss‐of‐function assays using siRNA or an inhibitor (bisamide) showed that downregulation of PIR expression blocked cancer cell migration and invasion. Moreover, the miR‐455‐5p/PIR axis contributed to cancer cell aggressiveness. These results suggest that PIR might be a promising diagnostic marker for HSPC and CRPC. Furthermore, CRPC treatment strategies targeting PIR may be possible in the future. Identification of antitumor miRNAs, including miRNA passenger strands, may contribute to the development of new diagnostic markers and therapeutic strategies for CRPC.

Silencing circular RNA UVRAG inhibits bladder cancer growth and metastasis by targeting the microRNA-223/fibroblast growth factor receptor 2 axis

Circular RNA UVRAG (circUVRAG), a type of non-coding RNA, is derived and cyclized by part of the exon from the UVRAG gene. However, the role of circUVRAG in bladder cancer (BLCA) has not been reported. The purpose of the present study was therefore to characterize the role of circUVRAG in BLCA. Bioinformatics analysis showed interactive relationships among circUVRAG, microRNA-223 (miR-223), and fibroblast growth factor receptor 2 (FGFR2). Quantitative real-time PCR was used to detect the expression of circUVRAG in BLCA cell lines. UM-UC-3 cells were stably transfected with siRNA against circUVRAG, and cell proliferation and migration ability were tested using the CCK8 assay, clone formation, and Transwell assays in vitro. Tumor xenograft formation and metastasis were determined using nude mice. Fluorescence in situ hybridization was used to confirm the subcellular localization of circUVRAG, and the luciferase reporter assay was used to confirm the relationships among circUVRAG, miR-223, and FGFR2. Results showed that circUVRAG was upregulated in BLCA cell lines. Downregulation of circUVRAG expression suppressed proliferation and metastasis both in vitro and in vivo. Downregulation of circUVRAG suppressed FGFR2 expression by "sponging" miR-223, which was confirmed by rescue experiments and luciferase reporter assay. Overall, the results showed that downregulation of circUVRAG suppressed the aggressive biological phenotype of BLCA. Taken together, silencing circular RNA UVRAG inhibited bladder cancer growth and metastasis by targeting the miR-223/FGFR2 axis, which may provide a potential biomarker and therapeutic target for the management of BLCA.