MiR-331-3p facilitates osteoporosis and may promote osteoporotic fractures by modulating NRP2 expression.

BACKGROUND: Osteoporosis (OP) is a high-incidence bone disease that is prone to osteoporotic fractures (OF), so it has attracted widespread attention. AIM: This study investigated the specific expression and role of miR-331 in patients with OP and OF. The findings have profound implications for the clinical prevention and treatment of these conditions. METHODS: The study included 60 OP patients, 46 OF patients, and 40 healthy controls. The expression level of miR-331-3p was detected using RT-qPCR. BMP2 was used to stimulate differentiation in MC3T3-E1 cells. After induction, the expression activity of osteogenic differentiation-related gene markers was detected using RT-qPCR. The target gene analysis was conducted using a luciferase reporter assay. RESULTS: The levels of miR-331-3p were significantly elevated, while NRP2 levels were significantly reduced in OF patients. Post-surgery, miR-331-3p levels decreased over time. MiR-331-3p was found to negatively regulate the luciferase activity of NPR2 in MC3T3-E1 cells. Furthermore, overexpression of miR-331-3p inhibited cell proliferation and decreased the levels of osteoblast differentiation markers. CONCLUSION: The up-regulation of miR-331-3p can promote OP and might also encourage the occurrence of OF by regulating NRP2. However, this needs further verification.

ICOSLG acts as an oncogene to promote glycolysis, proliferation, migration, and invasion in gastric cancer cells.

Gastric cancer (GC) has emerged as one of the most common malignancies in gastrointestinal system. Inducible T-cell costimulator ligand (ICOSLG) was found to be highly expressed in various cancers, which contributes to disease progression. This study aims to investigate the role of ICOSLG and its potential mechanism of action in dictating the aggressiveness of GC cell. ICOSLG and miR-331-3p expression patterns in cancerous and para-cancerous tissues from GC patients were examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The miRNAs targeting ICOSLG were predicted by "miRDB", "starBase," and "TargetScan" databases. The interplay of ICOSLG and miR-331-3p in dictating the aggressiveness and glycolysis of GC cells was investigated by CCK-8 proliferation assay and Transwell migration/invasion assays, as well as the detection of glucose uptake, lactate production and ATP levels. The tumorigenesis of GC cells after ICOSLG silencing was examined in the nude mice. ICOSLG was highly expressed in GC tissues, and GC patients with high ICOSLG expression showed a poorer prognosis than the low-expression group. Further, high ICOSLG level was correlated with more advanced TNM stages, more lymph-node metastases, and poorer tumor differentiation. ICOSLG knockdown inhibited the proliferation, migration, invasion and tumor formation of GC cells, which was concomitant with reduced glucose consumption, lactate production, and ATP levels. In contrast, ICOSLG overexpression enhanced the aggressiveness of GC cells, and this effect was abrogated after the treatment with glycolysis inhibitor. We further found that miR-331-3p was a negative regulator of ICOSLG4, and miR-331-3p overexpression reduced ICOSLG4 expression and suppressed the aggressive phenotype induced by ICOSLG4 in GC cells. Together, these findings indicate that ICOSLG4, as an oncogene, is upregulated to promote glycolysis and the malignant phenotype in GC cells. miR-331-3p, which is downregulated in GC tissues, functions as a negative regulator of ICOSLG4. Targeting miR-331-3p/ICOSLG4 axis could potentially suppress GC progression.

Role and mechanism of Circ-PDE7B in the formation of keloid.

The excessive proliferation of keloid fibroblasts is one of the important reasons leading to the formation of keloids. Circular RNA (circRNA) is an important regulator that regulates the biological functions of cells. However, the role and mechanism of circ-PDE7B in keloid formation have not been studied yet. QRT-PCR was used to detect the circ-PDE7B, miR-331-3p and cyclin-dependent kinase 6 (CDK6) expression. The biological functions of keloid fibroblasts were determined by MTT assay, flow cytometry, transwell assay and wound healing assay. Western blot analysis was used to measure the protein levels of extracellular matrix (ECM) markers and CDK6. The interaction between miR-331-3p and circ-PDE7B or CDK6 was confirmed by dual-luciferase reporter assay and RIP assay. Circ-PDE7B was found to be upregulated in keloid tissues and fibroblasts. Downregulation of circ-PDE7B could suppress the proliferation, invasion, migration, ECM accumulation and accelerate the apoptosis of keloid fibroblasts. Circ-PDE7B could serve as a sponge of miR-331-3p, and the regulation of silenced circ-PDE7B on the biological functions of keloid fibroblasts could be abolished by miR-331-3p inhibitor. Additionally, CDK6 was a target of miR-331-3p, and its overexpression could reverse the negative regulation of miR-331-3p on the biological functions of keloid fibroblasts. Circ-PDE7B sponged miR-331-3p to positively regulate CDK6 expression. Taken together, circ-PDE7B promoted the proliferation, invasion, migration and ECM accumulation of keloid fibroblasts by regulating the miR-331-3p/CDK6 axis, suggesting that circ-PDE7B might be a potential target for keloid treatment.

LncRNA HOTAIR enhances RCC2 to accelerate cervical cancer progression by sponging miR-331-3p

Purpose Long noncoding RNAs (lncRNAs) have been gradually regarded as influential indicators of various cancers. The present study aimed to identify the effects of lncRNA HOTAIR on cervical cancer progression. Methods RNA and protein expressions were quantified by RT-qPCR and western blot assays. Fluorescence in situ hybridization (FISH) assay was carried out to examine the intracellular location of HOTAIR. Cancer cell viability and mobility were detected by CCK-8, colony formation, transwell and wound healing assays. Binding relationships between miR-331-3p and HOTAIR/RCC2 were validated by luciferase reporter assay. Results RT-qPCR assays showed that HOTAIR levels were notably upregulated in cervical cancer tissues and cell lines. Furthermore, a fluorescence in situ hybridization (FISH) assay suggested that HOTAIR was mostly located in the cytoplasm of cancer cells, indicating a sponging function. CCK-8, colony formation, Transwell and wound-healing assays indicated that knockdown of HOTAIR in HeLa and SiHa cells significantly reduced cell growth, migration and invasion. Subsequently, miR-331-3p was proven to be the target molecule of HOTAIR. In addition, results from Pearson's correlation analysis indicated negative correlation between HOTAIR and miR-331-3p in cervical cancer tissues. HOTAIR negatively modulated miR-331-3p expression. Ultimately, the target gene of miR-331-3p was verified to be RCC2, and miR-331-3p negatively modulated RCC2 expression. In addition, analysis on clinical cervical cancer tissues confirmed the negative correlation between miR-331-3p and RCC2. HOTAIR and RCC2 showed oncogenic functions in HeLa and SiHa cells, while miR-331-3p exerted the reverse effect. Conclusions HOTAIR plays a carcinogenic role in cervical cancer by targeting the miR-331-3p/RCC2 axis (AU)

Circ_0005615 restrains the progression of multiple myeloma through modulating miR-331-3p and IGF1R regulatory cascade.

BACKGROUND: Circular RNAs are implicated in modulating the progression of various malignant tumors. However, the function and underlying mechanisms of circ_0005615 in multiple myeloma (MM) remain unclear. METHODS: The expression levels of circ_0005615, miR-331-3p and IGF1R were tested by quantitative real-time polymerase chain reaction or western blot assay. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine (EdU) assay were performed for cell proliferation detection. Cell apoptosis and cell cycle were measured by flow cytometry. The protein expressions of Bax and Bcl-2 were detected by western blot assay. Glucose consumption, lactate production and ATP/ADP ratios were estimated to disclose cell glycolysis. The interaction relationship among miR-331-3p and circ_0005615 or IGF1R was proved by dual-luciferase reporter assay. RESULTS: The abundance of circ_0005615 and IGF1R was increased in MM patients and cells, while the expression of miR-331-3p was decreased. Circ_0005615 inhibition retarded the proliferation and cell cycle progression, while reinforced the apoptosis of MM cells. Molecularly, circ_0005615 could sponge miR-331-3p, and the repressive trends of circ_0005615 deficiency on MM progression could be alleviated by anti-miR-331-3p introduction. Additionally, IGF1R was validated to be targeted by miR-331-3p, and IGF1R overexpression mitigated the suppressive function of miR-331-3p on MM development. Furthermore, IGF1R was mediated by circ_0005615/miR-331-3p axis in MM cells. CONCLUSION: Circ_0005615 downregulation blocked MM development by targeting miR-331-3p/IGF1R axis.

LncRNA HOTAIR enhances RCC2 to accelerate cervical cancer progression by sponging miR-331-3p.

PURPOSE: Long noncoding RNAs (lncRNAs) have been gradually regarded as influential indicators of various cancers. The present study aimed to identify the effects of lncRNA HOTAIR on cervical cancer progression. METHODS: RNA and protein expressions were quantified by RT-qPCR and western blot assays. Fluorescence in situ hybridization (FISH) assay was carried out to examine the intracellular location of HOTAIR. Cancer cell viability and mobility were detected by CCK-8, colony formation, transwell and wound healing assays. Binding relationships between miR-331-3p and HOTAIR/RCC2 were validated by luciferase reporter assay. RESULTS: RT-qPCR assays showed that HOTAIR levels were notably upregulated in cervical cancer tissues and cell lines. Furthermore, a fluorescence in situ hybridization (FISH) assay suggested that HOTAIR was mostly located in the cytoplasm of cancer cells, indicating a sponging function. CCK-8, colony formation, Transwell and wound-healing assays indicated that knockdown of HOTAIR in HeLa and SiHa cells significantly reduced cell growth, migration and invasion. Subsequently, miR-331-3p was proven to be the target molecule of HOTAIR. In addition, results from Pearson's correlation analysis indicated negative correlation between HOTAIR and miR-331-3p in cervical cancer tissues. HOTAIR negatively modulated miR-331-3p expression. Ultimately, the target gene of miR-331-3p was verified to be RCC2, and miR-331-3p negatively modulated RCC2 expression. In addition, analysis on clinical cervical cancer tissues confirmed the negative correlation between miR-331-3p and RCC2. HOTAIR and RCC2 showed oncogenic functions in HeLa and SiHa cells, while miR-331-3p exerted the reverse effect. CONCLUSIONS: HOTAIR plays a carcinogenic role in cervical cancer by targeting the miR-331-3p/RCC2 axis. Moreover, clinical cervical cancer tissues confirmed the negative correlation between miR-331-3p with lncRNA HOTAIR and RCC2. These data suggested an underlying therapeutic target for cervical cancer.

Neuropilin-2 Inhibits Drug Resistance and Progression of Melanoma Involving the MiR-331-3p Regulated Cascade.

BACKGROUND: MicroRNAs (miRs) are small noncoding RNAs that are crucial in the development and progression of tumours. Melanoma is an aggressive form of skin cancer and is resistant to most of the chemotherapeutic agents. However, the role of miRs in melanoma remains poorly studied. OBJECTIVE: The work aimed to demonstrate that miR-331-3p is downregulated in melanoma against the benign melanocytic nevi. METHODS: RT-PCR analysis was performed for the expression of proteins; cell proliferation and wound healing assays were carried out. Flow cytometry study was conducted for cell cycle analysis; colony formation assay was performed by soft agar method. For developing a tumour xenograft model, nu/nu mice were selected. RESULTS: Up-regulation of miR-331-3p in melanoma cells decreased cell proliferation, cell migration, and also drug resistance. Over-expression of miR-331-3p resulted in suppression of NRP2 and up-regulation of E-cadherin levels. Moreover, the levels of MDR1, ABCG-2, and ABCG-5 were decreased. However, the knockdown of NRP2 demonstrated similar effects as that of miR- 331-3p overexpression in tumour cells. Overexpression of miR-331-3p caused significant inhibition of tumour growth and its metastasis in mice model of melanoma, which was associated with depletion of NRP2 protein and increased expression of E-cadherin. However, the effects of miR- 331-3p on the migration, cell proliferation, and self-renewal were overturned by the upregulation of NRP2, which also resulted in the inhibition of E-cadherin and overexpression of MDR-1, ABCG-2, and ABCG-5. CONCLUSION: The findings point out the key role of miR-331-3p in the progression and drug resistance of melanoma involving NRP2.

Prostate Cancer-Associated miRNAs in Saliva: First Steps to an Easily Accessible and Reliable Screening Tool.

BACKGROUND: Common diagnostic tools for prostate cancer-prostate-specific antigen and transrectal biopsy-show only low predictive value and poor sensitivity. This study examines circulating miRNA in saliva to explore the possibility of a non-invasive and easy-to-execute diagnostic tool for prostate cancer screenings. METHODS: 16 miRNAs were extracted from salivary exosomes and analyzed via the delta-CT method. The presented method enables an application of the test in any health institution and even outpatient sector. Recruited participants were suspected to suffer from prostate cancer due to elevated PSA serum levels. Of these participants, 43 were diagnosed with prostate cancer, while 31 suffered from benign diseases and served as control group. RESULTS: hsa-mir-331-3p and hsa-mir-200b were significantly reduced in prostate cancer patients compared to the control group. ROC curve analysis revealed a reliable differentiation strength (AUC > 0.6) for both miRNAs with positive predictive values of 71% indicating prostate cancer. Differentiation of both groups based on PSA serum measurements was insufficient. The other 14 examined miRNAs showed no significant group differences. CONCLUSIONS: The presented method and miRNA are promising non-invasive tools to augment the current prostate cancer screening, thereby improving screening sensitivity and reducing numbers of false positive cancer suspects admitted to further invasive diagnostic and therapeutic steps.

Circular RNA circRASSF5 Functions as an Anti-Oncogenic Factor in Hepatocellular Carcinoma by Acting as a Competitive Endogenous RNA Through Sponging miR-331-3p.

Objective: Recently, emerging studies have validated that circular RNAs participate in multiple biological progresses in various human malignant tumors, including hepatocellular carcinoma (HCC). However, until now, the elucidated mechanism of circular RNAs is only the tip of the iceberg. In this study, we firstly identify a novel circular RNA circRASSF5 (the only circular RNA derived from the RASSF5 gene), and attempt to investigate its biological function and underlying mechanism in HCC. Methods: qRT-PCR, Western blotting and IHC were applied to detect the expression of related genes. CCK-8 assay, EdU staining, wound healing and transwell assays were used to investigate HCC proliferation, migration and invasion abilities. Animal model studies were included to investigate the function of circRASSF5 in HCC tumorigenesis and metastasis. RNA pull-down assay, luciferase reporter assay and FISH (fluorescence in situ hybridization) assay were performed to explore the potential biological mechanism underlying circRASSF5 function in HCC. Results: CircRASSF5 is obviously downregulated in both HCC tissues and cell lines. Low level of circRASSF5 is negatively associated with larger tumor size, severe vascular invasion, more portal vein tumor embolus and unfavorable prognosis. Loss-of-function assay reveals that circRASSF5 remarkably impedes the growth and metastasis of HCC cells in vitro and in vivo. Mechanistically, circRASSF5 directly interacts with miR-331-3p as a sponge, and then enhances the expression of PH domain and leucine-rich repeat protein phosphatase (PHLPP), thus restraining the progression of HCC cells. Conclusion: Altogether, we validate that circRASSF5 is a tumor suppressor in HCC, which competitively sponges with miR-331-3p and then enhances the tumor inhibitory effect of PHLPP, indicating the potential application value of circRASSF5 for HCC diagnosis and clinical treatment.

MicroRNA miR-331-3p suppresses osteosarcoma progression via the Bcl-2/Bax and Wnt/ß-Catenin signaling pathways and the epithelial-mesenchymal transition by targeting N-acetylglucosaminyltransferase I (MGAT1).

Osteosarcoma (OS) is a high-grade malignant disease that is a prevalent primary malignant sarcoma of the bone. The purpose of this investigation was to therefore elucidate the association between miR-331-3p and OS development and to identify a potential underlying mechanism. Key genes involved in OS were selected using GSE65071 dataset from the Gene Expression Omnibus (GEO) database and Gene Expression Profiling Interactive Analysis (GEPIA). Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting were conducted to detect miR-331-3p, MGAT1, the epithelial-mesenchymal transition (EMT), Bcl-2/Bax and Wnt/ß-Catenin signaling pathways related proteins. Dual-luciferase reporter assay and TargetScan were used for validating interaction between MGAT1 mRNA and miR-331-3p. Biological effects of miR-331-3p and MGAT1 on OS cells were detected employing MTT, Transwell, wound healing and flow cytometry, respectively. MiR-331-3p was under-expressed in OS, and up-regulation or inhibition of its expression could significantly inhibit or promote the malignant phenotypes of OS cells. Furthermore, we found that MGAT1, a target of miR-331-3p, had elevated expression in OS. Interestingly, MGAT1 could partially alleviate the effect of miR-331-3p in vitro. Collectively, miR-331-3p acts as an critical tumor suppressor through inhibiting MGAT1, results in suppressed Wnt/ß-Catenin pathway and decreased proliferation of OS cells; leads to increased apoptosis via Bcl-2/Bax pathway and inhibited migration and invasion ability via the EMT.

The circSPON2/miR-331-3p axis regulates PRMT5, an epigenetic regulator of CAMK2N1 transcription and prostate cancer progression.

BACKGROUND: Prostate cancer (PCa) is the most frequently diagnosed malignancy in men, and its mechanism remains poorly understood. Therefore, it is urgent to discover potential novel diagnostic biomarkers and therapeutic targets that can potentially facilitate the development of efficient anticancer strategies. METHODS: A series of functional in vitro and in vivo experiments were conducted to evaluate the biological behaviors of PCa cells. RNA pulldown, Western blot, luciferase reporter, immunohistochemistry and chromatin immunoprecipitation assays were applied to dissect the detailed underlying mechanisms. High-throughput sequencing was performed to screen for differentially expressed circRNAs in PCa and adjacent normal tissues. RESULTS: Upregulation of protein arginine methyltransferase 5 (PRMT5) is associated with poor progression-free survival and the activation of multiple signaling pathways in PCa. PRMT5 inhibits the transcription of CAMK2N1 by depositing the repressive histone marks H4R3me2s and H3R8me2s on the proximal promoter region of CAMK2N1, and results in malignant progression of PCa both in vitro and in vivo. Moreover, the expression of circSPON2, a candidate circRNA in PCa tissues identified by RNA-seq, was found to be associated with poor clinical outcomes in PCa patients. Further results showed that circSPON2 induced PCa cell proliferation and migration, and that the circSPON2-induced effects were counteracted by miR-331-3p. Particularly, circSPON2 acted as a competitive endogenous RNA (ceRNA) of miR-331-3p to attenuate the repressive effects of miR-331-3p on its downstream target PRMT5. CONCLUSIONS: Our findings showed that the epigenetic regulator PRMT5 aggravates PCa progression by inhibiting the transcription of CAMK2N1 and is modulated by the circSPON2/miR-331-3p axis, which may serve as a potential therapeutic target for patients with aggressive PCa.

Carcinoma-associated fibroblasts release microRNA-331-3p containing extracellular vesicles to exacerbate the development of pancreatic cancer via the SCARA5-FAK axis.

microRNA-331-3p (miR-331-3p) has been displayed as an oncogene in pancreatic cancer (PC). The current research set out to elucidate how miR-331-3p in carcinoma-associated fibroblasts (CAFs)-derived extracellular vesicles (EVs) facilitated the tumorigenesis in PC. First, a dual-luciferase reporter assay was adopted to investigate the relationship between miR-331-3p and SCARA5. In addition, EVs were isolated normal fibroblasts and CAFs, and these isolated EVs were co-cultured with PC cells. Cell proliferative and migrating/invasive potentials were further evaluated with the help of a CCK-8 and Transwell assays, respectively. Gain- and loss-of-function assays were also implemented to assess the role of miR-331-3p, SCARA5, and FAK pathway in PC cells. Lastly, xenograft nude mice were established to investigate the role of miR-331-3p in vivo. miR-331-3p negatively targeted SCARA5 and was highly expressed in CAFs-derived EVs, which accelerated the proliferative, migrating, and invasive potentials of PC cells. Meanwhile, over-expression of miR-331-3p enhanced the proliferative, migrating, and invasive properties of PC cells and promoted tumor growth in vivo by manipulating SCARA5/FAK axis, whereas SCARA5 countered the oncogenic effects of miR-331-3p. Overall, miR-331-3p in CAFs-derived EVs inhibits SCARA5 expression and activates the FAK pathway, thereby augmenting the progression of PC. Our study provides a potential therapeutic target for the treatment of PC.

Circular RNA circPSAP functions as an efficient miR-331-3p sponge to regulate proliferation, apoptosis and bortezomib sensitivity of human multiple myeloma cells by upregulating HDAC4.

BACKGROUND: Multiple myeloma (MM) is a malignant tumor of plasma cells in the bone marrow. Circular RNAs (circRNAs) exert important activity in the tumorigenesis and chemoresistance of MM. In the current work, we sought to identify the expression, activity, and mechanism of circPSAP activity in MM. METHODS: CircPSAP, microRNA (miR)-331-3p, and histone deacetylase 4 (HDAC4) were quantified by qRT-PCR and immunoblotting assays. Cell proliferation and survival were assessed by CCK-8 assay. Cell cycle and apoptosis were detected by flow cytometry. The direct relationship between miR-331-3p and circPSAP or HDAC4 3'UTR was validated by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. RESULTS: CircPSAP was overexpressed in human MM and high levels of circPSAP predicted poor prognosis in MM patients. CircPSAP depletion repressed cell proliferation and promoted apoptosis and BTZ sensitivity. Mechanistically, circPSAP functioned as a miR-331-3p sponge, and circPSAP regulated cell proliferation, apoptosis and BTZ sensitivity by sponging miR-331-3p. MiR-331-3p directly targeted and inhibited HDAC4. MiR-331-3p-mediated inhibition of HDAC4 impaired cell proliferation and enhanced cell apoptosis and BTZ sensitivity. Moreover, circPSAP modulated HDAC4 expression by acting as a miR-331-3p sponge. CONCLUSION: Our findings highlight a novel mechanism, in which circPSAP functions as a miR-331-3p sponge to impact MM cell proliferation, apoptosis and BTZ sensitivity by regulating HDAC4 expression.

Mechanism of lncRNA-H19 in Intestinal Injury of Mice with Ulcerative Colitis.

INTRODUCTION: Ulcerative colitis (UC) is a debilitating condition of the gastrointestinal system, and long non-coding RNA (lncRNA)-H19 emerges as a crucial player in inflammatory diseases. This study is designed to evaluate the mechanism of H19 in intestinal injury of UC mice and hint at a novel target for UC treatment. METHODS: UC mouse model was established, followed by injection of shH19, antagomir-331-3p, and tumor necrosis factor receptor-associated factor 4 (TRAF4) overexpression vector. H19, miR-331-3p, and TRAF4 expressions were detected via reverse transcription quantitative polymerase chain reaction. Intestinal injury was appraised via disease activity index (DAI), hematoxylin-eosin staining, and histopathological scoring. Interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-10 levels were detected via enzyme-linked immunosorbent assay. Binding relationships of H19 and miR-331-3p and TRAF4 were verified. RESULTS: H19 was highly expressed in colon tissues. Silencing H19 attenuated intestinal injury of UC mice, manifested by reductions in weight loss, DAI, histopathological scores, IL-1ß and TNF-α, and increases in colon length and IL-10. Mechanically, lncRNA-H19 is bound to miR-331-3p to inhibit its expression. TRAF4 is a target of miR-331-3p. Inhibition of miR-331-3p or overexpression of TRAF4 could reverse the alleviating role of lncRNA-H19 in intestinal injury of UC mice. CONCLUSION: LncRNA-H19 was highly expressed in UC mice and bound to miR-331-3p to promote TRAF4 transcription, thereby aggravating intestinal injury.

Circ_0045714/miR-331-3p interaction affects IL-1ß-evoked human articular chondrocyte injury through regulating PIK3R3 in a ceRNA regulatory cascade.

BACKGROUND: Osteoarthritis (OA) is characterized by joint pain and joint function limitation. Hsa_circ_0045714 (circ_0045714) is a novel OA-related circular RNA. However, its repertoire remains to be further clarified in joint chondrocytes. METHODS: RNA and protein expression levels and inflammatory factor levels were detected by real-time quantitative polymerase chain reaction, western blotting and enzyme-linked immunosorbent assay. Cell proliferation and apoptosis were determined by colony formation assay, cell counting kit-8 assay and apoptosis assay. Direct interaction was predicted by bioinformatics method and confirmed by dual-luciferase reporter assay. RESULTS: Expression of circ_0045714 and phosphoinositide-3-kinase (PI3K) regulatory subunit 3 (PIK3R3) was declined, and microRNA (miR)-331-3p was promoted in knee articular cartilages and cells from OA patients, as well as interleukin (IL)-1ß-challenged human articular chondrocytes (HAC) cell line. In stimulation of IL-1ß, HAC cells showed a loss of colony formation ability, cell viability and expression of Bcl-2 and Collagen II, allied with an increase in apoptosis rate and levels of IL-6, IL-8 and tumor necrosis factor-α, Bcl-2-associated X protein, cleaved caspase-3, and ADAM with thrombospondin motif-5. Noticeably, overexpressing circ_0045714 and inhibiting miR-331-3p could suppress IL-1ß-evoked these effects, and both were through up-regulating PIK3R3, a key gene in PI3K/AKT signaling pathway. Mechanically, circ_0045714 functioned as competing endogenous RNA (ceRNA) for miR-331-3p and further regulated expression of the downstream target gene PIK3R3. CONCLUSION: There was a novel circ_0045714/miR-331-3p/PIK3R3 ceRNA axis in HAC, and its inhibition might be one mechanism of HAC injury in OA.

Octreotide acetate combined with somatostatin upregulates miR-1291 and downregulates miR-331-3p in patients with cirrhosis and upper gastrointestinal bleeding.

OBJECTIVE: This study aimed to explore the efficacy of octreotide acetate combined with somatostatin (OA + SS) for the treatment of patients with cirrhosis and upper gastrointestinal bleeding (UGIB). METHODS: A total of 118 patients with cirrhosis and UGIB in our hospital were enrolled from June 2018 to September 2019. Fifty-seven were treated with OA alone (Group A) whereas 61 were treated with OA + SS (Group B). RESULTS: The therapeutic effects, inflammatory cytokines, liver function indices, and relative expression levels of miR-1291 and miR-331-3p were then observed. Compared with the patients in Group A, those in Group B had lower post-treatment inflammatory cytokine levels (P < 0.05), better post-treatment liver function indices (P < 0.05), lower incidences of adverse reactions (P < 0.05), and a higher total effective rate (P < 0.05). The OA + SS treatment group had upregulated miR-1291 and downregulated miR-331-3p (P < 0.05). CONCLUSION: OA + SS therapy is safe and effective for the treatment of patients with cirrhosis and UGIB.

Circular RNA hsa_circ_0026552 inhibits the proliferation, migration and invasion of trophoblast cells via the miR­331­3p/TGF­ßR1 axis in pre­eclampsia.

Globally, pre­eclampsia (PE) is a gestational disorder that causes increased morbidity of the fetus and mortality induced by pregnancy. Despite various studies, the understanding of the causes or mechanism of the development of PE remains elusive. Thus, the present study aimed to investigate the role of circular (circ)RNA hsa_circ_0026552 (hsa_circ_0026552) in the development of PE and its mechanism of regulation. hsa_circ_0026552 differential expression in PE tissue data and clinical samples were analyzed and it was observed that hsa_circ_0026552 is highly upregulated in PE samples. Furthermore, miR­331­3p was detected as an hsa_circ_0026552 target miRNA and TGF­ßR1 gene as a target of miR­331­3p. These results were confirmed using various assays, including dual­luciferase reporter, reverse transcription­quantitative PCR and RNA pull­down assay. It was observed that miR­331­3p expression was negatively correlated to hsa_circ_0026552 relative expression, while TGF­ßR1 expression was positively correlated to hsa_circ_0026552 expression evaluated by Pearson's correlation test. The functional experiments, including Cell Counting Kit­8, colony formation and Transwell assay, showed that silencing hsa_circ_0026552 could significantly strengthen the proliferation, migration and invasion of the trophoblastic HTR­8/SVneo cells, but the subsequent overexpression of hsa_circ_0026552 reversed this. Mechanistically, it was concluded that hsa_circ_0026552 acts as a miR­331­3p sponge to upregulate TGF­ßR1 expression in trophoblasts and is involved significantly in PE development and progression in pregnant women. The circRNA hsa_circ_0026552 could be a novel therapeutic target and prognostic biomarker for PE.

Hsa_circ_0004712 downregulation attenuates ovarian cancer malignant development by targeting the miR-331-3p/FZD4 pathway.

BACKGROUND: Circular RNAs (circRNAs) are gradually reported to be implicated in the development of malignant tumors, including ovarian cancer (OC). This paper intended to explore the function and action mechanism of hsa_circ_0004712 in OC. RESULTS: In our results, hsa_circ_0004712 was aberrantly overexpressed in OC tissues and cells. Downregulation of hsa_circ_0004712 impaired OC cell proliferation, colony formation, invasion and migration, and accelerated apoptosis. Hsa_circ_0004712 directly targeted miR-331-3p whose inhibitors reversed the effects of hsa_circ_0004712 downregulation. FZD4 was targeted by miR-331-3p, and hsa_circ_0004712 could positively regulated FZD4 expression by targeting miR-331-3p. The anti-tumor effects of miR-331-3p restoration were reversed by FZD4 overexpression. Downregulation of hsa_circ_0004712 also impaired tumor development in vivo by regulating miR-331-3p and FZD4. CONCLUSION: In conclusion, hsa_circ_0004712 deficiency repressed OC development by mediating the miR-331-3p/FZD4 pathway, predicting that hsa_circ_0004712 was a promising biomarker for OC diagnosis and therapy.

Circ_0062270 upregulates EPHA2 to facilitate melanoma progression via sponging miR-331-3p.

BACKGROUND: Circular RNA (circRNA) has been confirmed to play a vital role in melanoma progression. OBJECTIVE: The regulatory function of circ_0062270, a novel circRNA, in melanoma progression is unclear. METHODS: Relative expression levels of circ_0062270 and microRNA (miR)-331-3p were determined using qRT-PCR. Cell counting kit 8 assay, EdU staining and flow cytometry were used to measure cell proliferation, cell cycle distribution and apoptosis. The protein levels of proliferation, apoptosis and metastasis-related markers, as well as EPH receptor A2 (EPHA2), were tested using western blot analysis. Besides, cell migration and invasion were evaluated using transwell assay. Meanwhile, the interaction between miR-331-3p and circ_0062270 or EPHA2 was confirmed by dual-luciferase reporter assay or RIP assay. Additionally, tumor xenograft models were constructed to investigate the function of circ_0062270 on melanoma tumor growth in vivo. RESULTS: The expression of circ_0062270 was increased in melanoma tissues and cells. Knockdown of circ_0062270 inhibited proliferation, promoted apoptosis, and repressed metastasis in melanoma. Moreover, circ_0062270 could serve as miR-331-3p sponge, and miR-331-3p could target EPHA2. Furthermore, miR-331-3p inhibitor and EPHA2 overexpression reversed the inhibitory effect of circ_0062270 silencing on melanoma progression. In addition, silenced circ_0062270 also could inhibit melanoma tumor growth in vivo. CONCLUSION: Circ_0062270 accelerated the progression of melanoma through regulating the miR-331-3p/EPHA2 axis, suggesting that circ_0062270 might be a novel potential therapeutic target for melanoma.

Long Non-coding RNA MSTRG.24008.1 Regulates the Regeneration of the Sciatic Nerve via the miR-331-3p-NLRP3/MAL Axis.

Peripheral nerve injury (PNI) is a common clinical problem, which can cause severe disability and dramatically affect a patient's quality of life. Neural regeneration after PNI is a complex biological process that involves a variety of signaling pathways and genes. Emerging studies demonstrated that long non-coding RNAs (lncRNAs) were abnormally expressed after PNI and played pivotal roles in peripheral nerve regeneration. Based on the rat sciatic nerve injury model, we found that the expression levels of several lncRNAs were increased significantly in the sciatic nerve after injury. Software prediction prompted us to focus on one up-regulated lncRNA, MSTRG.24008.1. Dual-luciferase reporter assay, RNA pull-down assay and RNA interference approach verified that MSTRG.24008.1 regulated neuroregeneration via the miR-331-3p/nucleotide-binding oligomerization domain-like pyrin domain containing 3 (NLRP3)/myelin and lymphocyte protein (MAL) axis in vitro. Subsequently, we performed gastrocnemius muscle gravity and sciatic functional index experiments to evaluate the recovery of injured sciatic nerves after MSTRG.24008.1 siRNA interference in vivo. In conclusion, knockdown of MSTRG.24008.1 promotes the regeneration of the sciatic nerve via the miR-331-3p/NLRP3/MAL axis, which may provide a new strategy to evaluate and repair injured peripheral nerves clinically.