Urinary stem cell-derived exocrine circRNA ATG7 regulates the SOCS1/STAT3 signaling pathway through miR-4500, inhibits M1 macrophage polarization, and alleviates the progression of diabetes nephropathy.

OBJECTIVE: The etiopathogenesis of diabetes nephropathy (DN) has not yet been fully clarified. Finding effective treatments to prevent renal failure in DN patients has become the main focus of research in recent years. Circular RNA (circRNA) has been shown to play a momentous role in DN progression. Based on this, we aimed to investigate the potential mechanism by which urine-derived stem cell (USC)-derived exosome circRNA ATG7 (Exo-ATG7) mediates DN progression. METHODS: Exosomes from USCs were isolated and identified. The DN rat model was established by intraperitoneally injecting 60 mg/kg streptozotocin. The protein expression levels were measured by Western blot and immunofluorescence. HE and Masson staining were used to evaluate renal injury, and the expression of related genes was detected by RT-qPCR. RESULTS: CircRNA ATG7 was significantly downregulated in the DN rat model, and the extracellular vesicles of USCs improved renal function and reduced inflammation in DN rats. However, after knocking down the USCs-derived exosome circRNA ATG7, improvement and therapeutic effect on renal function in DN rats were lost. In addition, overexpression of ATG7 facilitated the switching of macrophages from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype both in vivo and in vitro. Mechanistically, upregulation of circRNA ATG7 expression can alleviate renal damage in DN rats. Importantly, the USCs-derived exosome circRNA ATG7 promotes macrophage M2 polarization by regulating the SOCS1/STAT3 signaling pathway through miR-4500. In addition, animal experiments also confirmed that after knocking down ATG7 in USC cells, the extracted exosome-treated DN rats could weaken the therapeutic effect of USC exosomes. CONCLUSION: Our research results indicate that USC-derived exosomal circRNA ATG7 facilitates macrophage phenotype switching from M1 to M2 through the SOCS1/STAT3 signaling pathway mediated by miR-4500, thereby inhibiting DN progression.

The lncRNA OIP5-AS1/miR-4500 axis targeting ARG2 modulates oxidative stress-induced premature senescence in endothelial cells: implications for vascular aging.

BACKGROUND: Endothelial senescence due to increased age or oxidative stress can cause endothelial dysfunction, which is strongly associated with the pathogenesis of cardiovascular diseases (CVDs). RESEARCH DESIGN AND METHODS: Hydrogen peroxide (H2O2) was used to induced human umbilical vein endothelial cells (HUVECs) senescence model. Cell senescence and cell proliferation were assessed by SA-ß-gal staining and PCNA staining. Nitric oxide (NO) and reactive oxygen species (ROS) levels were detected by DAF-2 DA and DCFH-DA. Inflammatory indicators were quantified by qPCR. Meanwhile, western blot was used to examine the ARG2 protein. Finally, an aging mice model induced by H2O2 was established to confirm the role of OIP5-AS1/miR-4500/ARG2 in endothelial dysfunction in vivo. RESULTS: ARG2 was upregulated and miR-4500 was reduced in H2O2-induced HUVECs. MiR-4500 negatively regulates ARG2 expression, meanwhile ameliorating H2O2-induced ECs senescence and dysfunction. Targeted interactions among OIP5-AS1, miR-4500, and ARG2 were confirmed by dual-luciferase reporter assays. OIP5-AS1 as miR4500 sponge negatively mediates miR-4500 expression, and is upregulated upon H2O2 stimulation in HUVECs. OIP5-AS1 depletion shows the protective effects on H2O2-induced ECs senescence, dysfunction, and SASP. In vivo, a higher expression of OIP5-AS1 and ARG2 in the aortas of aged mice. CONCLUSIONS: We disclosed a regulatory mechanism for OIP5-AS1/miR-4500/ARG2 in the regulation of oxidative stress-related ECs senescence and vascular aging.

LINC00265/miR-4500 Axis Accelerates Acute Lymphoblastic Leukemia Progression by Enhancing STAT3 Signals.

BACKGROUND: Long noncoding RNA LINC00265 or miR-4500 is involved in the pathogenesis of many cancers. However, their functions in acute lymphoblastic leukemia (ALL) remain unknown. In this study, we investigated how LINC00265 and miR-4500 regulate the malignant characteristics of ALL. METHODS: Real-time PCR was used in examining the expression of LINC00265 in ALL cell lines and blood of patients with ALL. Cell proliferation, cell migration, and xenograft tumor assays were performed to verify the function of LINC00265 subjected to overexpressing and silencing experiments. The ceRNA mechanism with LINC00265/miR-4500/STAT3 was investigated through luciferase and RNA pull-down assays. Finally, the function of the LINC00265/miR-4500/STAT3 axis subjected to overexpressing and silencing assays was determined through cell proliferation, cell migration, and xenograft tumor assays. RESULTS: LINC00265 was highly expressed in ALL cell lines and blood of patients with ALL and facilitated the proliferation, migration, invasion, and growth of xenograft tumors of ALL cells. The silencing of LINC00265 expression with LINC00265 siRNA significantly inhibited the malignancy of the ALL cells. RNA pull-down and luciferase assays demonstrated that LINC00265 competitively targeted miR-4500 and enhanced STAT3 expression. Furthermore, miR-4500 inhibitors or overexpressed LINC00265 up-regulated STAT3 expression, and miR-4500 mimics or STAT3 shRNAs eliminated the LINC00265-induced malignancy of the ALL cells. CONCLUSION: Mechanistically, LncRNA LINC00265 can competitively interact with miR-4500 and thereby up-regulates STAT3 signaling and enhances the malignancy of tumors.

Exosome-derived SNHG16 sponging miR-4500 activates HUVEC angiogenesis by targeting GALNT1 via PI3K/Akt/mTOR pathway in hepatocellular carcinoma.

Accumulating evidence suggests cancer-derived exosomes play an important role in promoting angiogenesis. Long noncoding RNA small nucleolar RNA host gene 16 (SNHG16) is known to aggravate hepatocellular carcinoma (HCC) progression. However, the function of exosomal SNHG16 in HCC angiogenesis remains unclear. In this study, the expression of SNHG16 was significantly upregulated in HCC tissues and cell lines. The proliferative, migratory, and angiogenic abilities of HUVECs were enhanced after exposure to exosomes derived from HCC cells by transmitting SNHG16. In addition, SNHG16 was validated to promote the biological function of HUVECs directly. Exosomal SNHG16 increased GALNT1 expression to promote angiogenesis via sponging miR-4500. SNHG16/miR-4500/GALNT1 axis played an important role in exosome-mediated angiogenesis and tumor growth in vitro and vivo. Furthermore, SNHG16 activated PI3K/Akt/mTOR pathway via competing endogenous miR-4500 and GALNT1. Meanwhile, the expression of plasma exosomal SNHG16 upregulated in the plasma of HCC patients. These data elucidated the essential role of exosomal SNHG16 in communication between HCC cells and endothelial cells. Exosomal SNHG16 could be utilized as a therapeutic target for anti-angiogenesis in HCC progression.

LINC01287 facilitates proliferation, migration, invasion and EMT of colon cancer cells via miR-4500/MAP3K13 pathway.

BACKGROUND: Accumulated studies indicate that aberrant expression of long noncoding RNAs (lncRNAs) is associated with tumorigenesis and progression of colon cancer. In the present study, long intergenic non-protein coding RNA 1287 (LINC01287) was identified to up-regulate in colon cancer by transcriptome RNA-sequencing, but the exact function remained unclear. METHODS: Transcriptome RNA-sequencing was conducted to identify dysregulated lncRNAs. Expression of LINC01287 was evaluated by real-time quantitative PCR. The downstream targets of LINC01287 and miR-4500 were verified by luciferase reporter assay, pull down assay and western blot. The potential functions of LINC01287 were evaluated by cell viability assay, colony formation assay, soft agar assay, flow cytometry, transwell migration and invasion assay, and tumor xenograft growth in colon cancer cells. RESULTS: Our results indicated that LINC01287 was up-regulated in colon cancer patients. High LINC01287 expression was associated with advanced TNM stage, lymph node metastasis, distant metastasis and shorter overall survival. Knockdown of LINC01287 inhibited cell growth, colony formation in plates and soft agar, transwell cell migration and invasion, and epithelial-mesenchymal transition (EMT) of colon cancer cells, while LINC01287 overexpression had contrary effects. In addition, LINC01287 mediated MAP3K13 expression by sponging miR-4500, thus promoted NF-κB p65 phosphorylation. Restored MAP3K13 expression or miR-4500 knockdown partially abrogated the effects of silencing LINC01287 in colon cancer cells. CONCLUSION: Our findings demonstrated that the LINC01287/miR-4500/MAP3K13 axis promoted progression of colon cancer. Therefore, LINC01287 might be a potential therapeutic target and prognostic marker for colon cancer patients.

Circular RNA circPLK1 promotes breast cancer cell proliferation, migration and invasion by regulating miR-4500/IGF1 axis.

BACKGROUND: Circular RNAs (circRNAs) can regulate gene expression in different malignancies. However, the biological functions of circRNA polo-like kinase-1 (circPLK1) in the tumorigenesis of breast cancer (BC) and its potential mechanisms have not been well elucidated yet. METHODS: The expression levels of circPLK1, microRNA-4500 (miR-4500), insulin-like growth factor 1 (IGF1) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Cell viability, cell cycle distribution, cell migration and invasion were determined by Cell Counting Kit-8 (CCK-8) assay, flow cytometry and transwell assay, respectively. Western blot assay was used to analyze the protein levels of cyclin-dependent kinase (CDK) 4 and CDK-6. The relationship between miR-4500 and circPLK1 or IGF1 was predicted by starBase v3.0 and verified by dual-luciferase reporter assay and RNA pull-down assay. The mice xenograft model was established to investigate the roles of circPLK1 in vivo. RESULTS: CircPLK1 and IGF1 were upregulated and miR-4500 was downregulated in BC tissues and cells. Interference of circPLK1 inhibited BC cell growth, migration and invasion, which was reversed by overexpression of IGF1. Moreover, circPLK1 could directly bind to miR-4500 and IGF1 was verified as a direct target of miR-4500. Furthermore, IGF1 overexpression abated the inhibitory effects of miR-4500 upregulation on proliferation, migration and invasion of BC cells. Mechanically, circPLK1 was a sponge of miR-4500 to regulate IGF1 expression in BC cells. Besides, circPLK1 knockdown suppressed tumor growth via upregulating miR-4500 and downregulating IGF1. CONCLUSIONS: CircPLK1 silence inhibited BC cell growth, migration and invasion by regulating miR-4500/IGF1 axis, suggesting circPLK1/miR-4500/IGF axis might be a potential therapeutic target.

Promotion of BZW2 by LINC00174 through miR-4500 inhibition enhances proliferation and apoptosis evasion in laryngeal papilloma.

BACKGROUND: We aimed to explore the roles of basic leucine zipper and W2 domains (BZW) 2 in the human papillomavirus-infected laryngeal papillomatosis. METHODS: In the present study, BZW 2 knockdown and overexpressed cell lines were constructed. CCK-8 and colony formation assays were used to determine cell proliferation. Caspase-3 activity and nucleosomes fragmentation assays were used to determine cell apoptosis. qRT-PCR and Western blot were employed to evaluate the mRNA and protein levels of target genes, respectively. Luciferase and biotin-coupled miRNA pulldown assays were used to examine the interactions between mRNA and mRNA. RESULTS: We observed the levels of BZW2 were up-regulated in the laryngeal papilloma (LP) tissues as compared with adjacent tissues. The knockdown of BZW2 significantly inhibited cell proliferation and promoted cell apoptosis in the LP cells. Additionally, we identified the expressions of BZW2 negatively regulated by miR-4500. Luciferase and biotin-coupled miRNA pulldown assays demonstrated that LINC00174 competed with the BZW2 for binding with miR-4500. Moreover, the results showed that LINC00174/miR-4500/BZW2 axis regulated cell proliferation and apoptosis. CONCLUSION: Our results demonstrated that the regulation of LINC00174/miR-4500/BZW2 axis might be used as an effective strategy for treatment of human papillomavirus-infected laryngeal papillomatosis.

LncRNA TRG-AS1 stimulates hepatocellular carcinoma progression by sponging miR-4500 to modulate BACH1.

BACKGROUND: T cell receptor gamma locus antisense RNA 1 (TRG-AS1) has been reported to involve in the progression of glioblastoma, however the role and its underlying molecular mechanism in hepatocellular carcinoma (HCC) remain unknown. METHODS: Quantitative real-time polymerase chain reaction (RT-qPCR) was applied to detect TRG-AS1 expression in HCC cells. Besides, the proliferation abilities of HCC cells were assessed by colony formation and EdU assays. The migratory and invasive abilities of HCC cells were examined by transwell assays. Imunofluorescence staining (IF) was used to analyze the epithelial-mesenchymal transitions (EMT). The interaction among TRG-AS1, miR-4500 and BTB domain and CNC homolog 1 (BACH1) were proofed by means of RIP and RNA pull down and luciferase reporter assays. RESULTS: TRG-AS1 was conspicuously overexpressed in HCC cells. TRG-AS1 silencing apparently suppressed HCC cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT). Mechanism exploration revealed that TRG-AS1 acted as a molecular sponge of miR-4500 to regulate BACH1. MiR-4500 silencing or BACH1 overexpression in BACH1-downregulated cells fully rescued cell proliferation migration, invasion and EMT progress. CONCLUSION: TRG-AS1 regulates HCC progression by targeting miR-4500/BACH1 axis.

miR-4500 suppresses cell proliferation and migration in bladder cancer via inhibition of STAT3/CCR7 pathway.

Bladder cancer (BC) is a prevalent type of cancer that occurs in human urinary system threatening the human health. microRNA-4500 (miRNA-4500) is a novel miRNA that serves as a potential biomarker in several types of cancers. However, the in-depth molecular mechanism of miR-4500 in BC has not yet been fully elucidated. Quantitative real-time polymerase chain reactionq and Western blot analysis were applied to analyze the expressions of miR-4500, STAT3, and C-C chemokine receptor 7 (CCR7). Gain-of-function assays involving Cell Counting Kit-8, 5'-ethynyl-2'-deoxyuridine incorporation assay, and Transwell were employed to evaluate miR-4500 function in cell proliferation and migration. Moreover, chromatin immunoprecipitation, RNA immunoprecipitation, and luciferase reporter assay were performed to explore the molecular mechanism underlying function of miR-4500. We found the downregulation of miR-4500 in BC cells, and ectopic expression of miR-4500 hampered cell proliferation, migration, and epithelial-to-mesenchymal transition. Importantly, miR-4500 directly targeted STAT3 3'-untranslated region, leading to repression on STAT3 expression. Intriguingly, STAT3 transcriptionally regulated CCR7. Rescue experiments validated the presence of miR-4500/STAT3/CCR7 axis in control of BC growth and progression. Our data highlighted miR-4500 as a potent cancericidal gene in BC, and might provide a theoretical grounding for development of target-oriented therapies of patients afflicted with BC.

LncRNA SNHG16 aggravates tumorigenesis and development of hepatocellular carcinoma by sponging miR-4500 and targeting STAT3.

Hepatocellular carcinoma (HCC) is the most common type of primary liver tumor and becomes a lethal malignancy on account of high mortality and increasing incidence. A growing body of studies has proved that long noncoding RNAs (lncRNAs) participate in the development of diverse cancers. Although it has been commonly accepted that SNHG16 is a procancer gene in numerous cancers, the regulatory mechanism of SNHG16 in HCC still needs more explorations. In this study, our results delineated that SNHG16 presented much higher expression levels in HCC tissues and cells, particularly in advanced stages of HCC. Enhanced SNHG16 expression was strongly related to poor prognosis. SNHG16 facilitated HCC progression by promoting cell proliferation, migration, invasion, and epithelial-mesenchymal transition process as well as inhibiting cell apoptosis. SNHG16 served as a sponge for miR-4500 in HCC and miR-4500 neutralized the influences of SNHG16 knockdown on HCC. SNHG16 was confirmed to compete with signal transducer and activator of transcription 3 (STAT3) to bind with miR-4500. SNHG16 aggravated the development of HCC via sponging miR-4500 so as to upregulate STAT3. In other words, this study was the first to investigate the potential mechanism of SNHG16 in HCC and verified SNHG16 exerted its carcinogenesis by miR-4500/STAT3 axis, suggesting SNHG16 may be a new underlying therapeutic target for HCC treatment.

Ursolic Acid Induces Apoptosis in Colorectal Cancer Cells Partially via Upregulation of MicroRNA-4500 and Inhibition of JAK2/STAT3 Phosphorylation.

Though ursolic acid (UA) isolated from Oldenlandia diffusa was known to exhibit anti-cancer, anti-inflammatory, and anti-obesity effects, the underlying antitumor mechanism of ursolic acid was not fully understood to date. Thus, in the present study, the apoptotic mechanism of ursolic acid was elucidated in HCT116 and HT29 colorectal cancer cells in association with STAT3 and microRNA-4500 (miR-4500) by MTT assay, Terminal deoxynucleotidyl transferase-dT-mediated dUTP nick end labelling (TUNEL) assay, cell cycle analysis, immunofluorescence, and Western blotting. Ursolic acid significantly exerted cytotoxicity, increased TUNEL positive cells and sub-G1 apoptotic portion, induced cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP) and caspase 3 in HCT116 and HT29 cells. Of note, ursolic acid attenuated the expression of anti-apoptotic proteins such as Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) and also blocked nuclear translocation of STAT3 in colorectal cancer cells. Notably, ursolic acid increased the expression level of miR-4500 in HCT116 cells by qRT-PCR analysis and conversely miR-4500 inhibitor reversed cytotoxic, anti-proliferative, and apoptotic effects by increasing TUNEL positive cells, PARP cleavage and inhibiting p-STAT3 in ursolic acid treated colorectal cancer cells. Overall, our findings provide evidence that usolic acid induces apoptosis in colorectal cancer cells partially via upregulation of miR-4500 and inhibition of STAT3 phosphorylation as a potent anti-cancer agent for colorectal cancer therapy.

MiR-4500 is epigenetically downregulated in colorectal cancer and functions as a novel tumor suppressor by regulating HMGA2.

This study aimed to understand the exact function and potential mechanism of miR-4500 in colorectal cancer (CRC). In this study, the expression of miR-4500 was decreased in both CRC cells and tissues, and downregulated miR-4500 indicated advanced tumor stage and poor survival. By bisulfite sequencing analysis, we found that the CpG island in the promoter region of miR-4500 was hypermethylated in CRC cells and tissues compared with normal control cells and non-tumor tissues, respectively. Functionally, gain- and loss-of-function analyses indicated the tumor suppressor role of miR-4500: it suppressed cell proliferation, cell cycle progression, migration, and invasion. Predictive algorithms and experimental analyses identified HMGA2 as a direct target of miR-4500. Reintroducing HMGA2 impaired the inhibitory effects of miR-4500 on cell growth and motility. Clinically, higher HMGA2 protein expression in CRC tissues was associated with advanced tumor stage and poor survival. An inverse correlation was found between miR-4500 levels and HMGA2 protein expression. Taken together, this study provides the first evidence that miR-4500 functions as a novel tumor suppressor in the miR-4500/HMGA2 axis in colorectal carcinogenesis, and restoring miR-4500 expression might represent a promising therapeutic strategy for CRC.