MicroRNA-379-5p plays a tumor-suppressive role in human bladder cancer growth and metastasis by directly targeting MDM2

CircFSCN1 induces tumor progression and triggers epithelial-mesenchymal transition in bladder cancer through augmentation of MDM2-mediated p53 silencing

BACKGROUND

Compelling evidences indicated that circular RNA (circRNA) was a novel class of non-coding RNA that played critical and distinct roles in various human cancers. Their roles and underlying mechanisms, however, in bladder cancer (BC) remained largely unknown.

METHODS

A novel circRNA derived from oncogene FSCN1, namely circFSCN1, was selected from a microarray analysis. The phenotypic alterations were assessed with functional experiments in vitro and in vivo. RNA immunoprecipitation, RNA pull-down, luciferase reporter assay, and rescue experiments were sequentially proceeded to clarify the interactions among circFSCN1, miR-145-5p, MDM2, and p53.

RESULTS

We observed that the expression of circFSCN1 was elevated in BC cell lines and tissues. Next, we validated the fundamental properties of circFSCN1. In the meanwhile, we noticed that elevated circFSCN1 level, pathological T stage, and tumor grade were identified as independent factors associated with cancer-specific survivals of patients with BC，as determined by univariate and multivariable COX regression analyses. Phenotype studies demonstrated the promoting effects of circFSCN1 on the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of BC cells. Mechanistically, we elucidated that circFSCN1, primarily localized in the cytoplasm, upregulated the expression of MDM2, a well-known inhibitor of p53, by directly binding to miR-145-5p.

CONCLUSIONS

Elevated circFSCN1 induces tumor progression and EMT in BC via enhancing MDM2-mediated silencing of p53 by sponging miR-145-5p. Targeting circFSCN1, a novel identified target, may be conducive in impeding BC progression and providing survival benefits for patients with BC.

Circ_SIPA1L1 Promotes Osteosarcoma Progression Via miR-379-5p/MAP3K9 Axis

Background: Osteosarcoma (OS) is a common malignant bone tumor. Circular RNAs (circRNAs) exert important roles in the pathogenesis of human cancers, including OS. In this study, the authors focused on the role and mechanism of circRNA signal-induced proliferation-associated 1 like 1 (circ_SIPA1L1) in OS. Methods: The enrichment of SIPA1L1, circ_SIPA1L1, microRNA-379-5p (miR-379-5p), and mitogen-activated protein kinase kinase kinase 9 (MAP3K9) was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The colony formation capacity was assessed through colony formation assay. Transwell assays were used to detect the migration and invasion abilities. Western blot assay was used to measure the expression of metastasis-related proteins and MAP3K9. The target interactions between the genes in circ_SIPA1L1/miR-379-5p/MAP3K9 axis were predicted by StarBase and confirmed by dual-luciferase reporter assay. The in vivo role of circ_SIPA1L1 was verified by murine xenograft assay. Results: Circ_SIPA1L1 abundance was aberrantly elevated in OS tissues and cell lines. Circ_SIPA1L1 accelerated the proliferation and metastasis abilities of OS cells. Circ_SIPA1L1 promoted the malignant behaviors of OS cells through elevating MAP3K9 level. MiR-379-5p directly bound to circ_SIPA1L1 and MAP3K9. MiR-379-5p interference rescued the abilities of proliferation and metastasis in OS cells, which were suppressed by the silencing of circ_SIPA1L1. Circ_SIPA1L1 promoted the development of OS via miR-379-5p/MAP3K9 in vivo. Conclusion: Circ_SIPA1L1 promoted the progression of OS via miR-379-5p/MAP3K9 axis.

Functional In Vivo Screening Identifies microRNAs Regulating Metastatic Dissemination of Prostate Cancer Cells to Bone Marrow

Distant metastasis is the major cause of cancer-related deaths in men with prostate cancer (PCa). An in vivo functional screen was used to identify microRNAs (miRNAs) regulating metastatic dissemination of PCa cells. PC3 cells transduced with pooled miRZiP™ lentivirus library (anti-miRNAs) were injected intraprostatic to 13 NSG mice followed by targeted barcode/anti-miR sequencing. PCa cells in the primary tumours showed a homogenous pattern of anti-miRNAs, but different anti-miRNAs were enriched in liver, lung, and bone marrow, with anti-miR-379 highly enriched in the latter. The bone metastasis-promoting phenotype induced by decreased miR-379 levels was also confirmed in a less metastatic PCa cell line, 22Rv1, where all mice injected intracardially with anti-miR-379-22Rv1 cells developed bone metastases. The levels of miR-379 were found to be lower in bone metastases compared to primary tumours and non-cancerous prostatic tissue in a patient cohort. In vitro functional studies suggested that the mechanism of action was that reduced levels of miR-379 gave an increased colony formation capacity in conditions mimicking the bone microenvironment. In conclusion, our data suggest that specific miRNAs affect the establishment of primary tumours and metastatic dissemination, with a loss of miR-379 promoting metastases in bone.

Roles of non-coding RNAs in the metabolism and pathogenesis of bladder cancer

Bladder cancer (BC) is featured as the second most common malignancy of the urinary tract worldwide with few treatments leading to high incidence and mortality. It stayed a virtually intractable disease, and efforts to identify innovative and effective therapies are urgently needed. At present, more and more evidence shows the importance of non-coding RNA (ncRNA) for disease-related study, diagnosis, and treatment of diverse types of malignancies. Recent evidence suggests that dysregulated functions of ncRNAs are closely associated with the pathogenesis of numerous cancers including BC. The detailed mechanisms underlying the dysregulated role of ncRNAs in cancer progression are still not fully understood. This review mainly summarizes recent findings on regulatory mechanisms of the ncRNAs, long non-coding RNAs, microRNAs, and circular RNAs, in cancer progression or suppression and focuses on the predictive values of ncRNAs-related signatures in BC clinical outcomes. A deeper understanding of the ncRNA interactive network could be compelling framework for developing biomarker-guided clinical trials.

Pro-fibrotic and apoptotic activities of circARAP1 in myocardial ischemia-reperfusion injury

Reperfusion modality can cause damage to cardiomyocytes, known as myocardial ischemia-reperfusion injury (MI/RI). Circular RNAs (circRNAs) are fundamental regulators associated with many cardiac diseases, including MI/RI. However, their functional impact on cardiomyocyte fibrosis and apoptosis remains elusive. Therefore, this study aimed to explore possible molecular mechanisms of circARPA1 in animal models and in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. GEO dataset analysis showed that has_circ_0023461 (circARPA1) was differentially expressed in myocardial infarction samples. Real-time quantitative PCR further supported that circARPA1 was expressed at high levels in animal models and in H/R-triggered cardiomyocytes. Then, loss-of-function assays were performed to show that circARAP1 suppression effectively ameliorated cardiomyocyte fibrosis and apoptosis in MI/RI mice. Mechanistic experiments showed that miR-379-5p, KLF9 and Wnt signaling pathways were associated with circARPA1. circARPA1 can sponge miR-379-5p to regulate KLF9 expression, thereby activating the wnt/β-catenin pathway. Finally, gain-of-function assays revealed that circARAP1 aggravated MI/RI in mice and H/R-induced cardiomyocyte injury by regulating the miR-379-5p/KLF9 axis to activate Wnt/β-catenin signaling.

LncRNA SNHG1 Facilitates Tumor Proliferation and Represses Apoptosis by Regulating PPARγ Ubiquitination in Bladder Cancer

Simple Summary

Our study elucidated that SNHG1 promotes MDM2 expression by binding to miR-9-3p to promote PPARγ ubiquitination and downregulate PPARγ expression and that SNHG1 plays an important role in bladder cancer and provides a potential therapeutic target for bladder cancer.

Abstract

Background: Long noncoding RNAs regulate various biological effects in the progression of cancers. We found that the expression of SNHG1 was significantly up-regulated in bladder cancer after analyzing data obtained from TCGA and GEO. However, the potential role of SNHG1 remains to be investigated in bladder cancer. It was validated that SNHG1 was overexpressed in bladder cancer tissues detected by qRT-PCR and FISH, which was also associated with poor clinical outcome. Additionally, SNHG1 was verified to facilitate tumor proliferation and repress apoptosis in vitro and in vivo. Results: SNHG1 could act as a competitive endogenous RNA and decrease the expression of murine double minute 2 (MDM2) by sponging microRNA-9-3p. Furthermore, MDM2 induced ubiquitination and degradation of PPARγ that contributed to the development of bladder cancer. Conclusions: the study elucidated that SNHG1 played an important role in bladder cancer and provided a potential therapeutic target for bladder cancer.

lncRNA MNX1‑AS1 promotes prostate cancer progression through regulating miR‑2113/MDM2 axis

A growing number of dysregulated long non-coding (lnc)RNAs have been verified to serve an essential role in human prostate cancer. However, the underlying mechanisms of lncRNA MNX1 Antisense RNA 1 (MNX1-AS1) in prostate cancer has not been explored. Therefore, the present study aimed to explore the function of MNX1-AS1 in prostate cancer tumorigenesis and investigate the in-depth mechanism. The expression of MNX1-AS1, microRNA (miR)-2113 and murine double min 2 (MDM2) in prostate cancer tissues and corresponding normal tissues were assessed by reverse transcription-quantitative PCR. The protein expression levels of MDM2 were detected by western blotting. LNCaP and PC-3 cells were transfected with short hairpin (sh)-MNX1-AS1, miR-2113 mimics, miR-2113 inhibitor and pCDH-MDM2 vector using Lipofectamine^® 3000. Cell proliferation, migration and invasion abilities were assessed by CCK-8 assay, colony formation and Transwell assay, respectively. Dual luciferase reporter assay was carried out to confirm the putative targets of MNX1-AS1 and miR-2113. Tumor formation experiment in nude mice was applied to evaluate the tumor growth effect of MNX1-AS1 in vivo. The expression of MNX1-AS1 was significantly upregulated in the prostate cancer tissues and cell lines. MNX1-AS1 knockdown suppressed the abilities of cell viability and migration and invasion in vitro and inhibited tumor growth in vivo. Additionally, luciferase reporter assay revealed that MNX1-AS1 could target miR-2113 and negatively interacted with miR-2113 in prostate cancer cells. miR-2113 directly targeted to MDM2 and negatively modulated the expression of MDM2. Rescue assays suggested that the viability, migration and invasion of impaired cells triggered by transfection with sh-MNX1-AS1 alone could be recovered by co-transfection with sh-MNX1-AS1 + miR-2113 inhibitor or sh-MNX1-AS1 + pCDH- MDM2 vector. The present study demonstrated that MNX1-AS1 promoted prostate cancer progression through regulating miR-2113/ MDM2 axis.

CircMCTP2 (has-circ-0000658) facilitates the proliferation and metastasis of bladder carcinoma through modulating the miR-498/murine double minute-2 axis

CircMCTP2 is a novel circRNA, which is associated with various kinds of malignant tumors progression, such as gastric cancer. However, the function of circMCTP2 in bladder carcinoma (BC) has no idea. The purpose of this study was tantamount to functionally dissect circMCTP2 in the progression of BC. In our study, circMCTP2 expression was strongly increased in BC tissues and cell lines. High expression of circMCTP2 predicted a poor prognosis of BC patients. CircMCTP2 deficiency impaired the cell growth, migration as well as invasive ability of BC cell lines (J82 and T24). In vivo, circMCTP2 deficiency cut the tumor growth rates and the tumor weight. In BC cells, circMCTP2 deficiency enhanced the translation of E-cadherin, while diminishing the translation of N-cadherin, Vimentin, and Snail. Moreover, circMCTP2 acted as a sponge of miR-498 to regulate murine double minute-2 (MDM2) expression. In BC tissues, a negative correlation was observed between the expression levels of circMCTP2 and miR-498. Additionally, either miR-498 silencing or MDM2 over-expression augmented the carcinogenic action of circMCTP2 on BC. In conclusion, our study showed that circMCTP2 regulates the expression of MDM2 by sponging miR-498 to promote the development of BC. These findings offer a new strategy for early diagnosis of BC and its therapeutics.

Circ_0011292 Enhances Paclitaxel Resistance in Non-Small Cell Lung Cancer by Regulating miR-379-5p/TRIM65 Axis

Background: Non-small cell lung cancer (NSCLC) is the most prevalent cancer in the world. Chemotherapy resistance is a major obstacle to NSCLC therapy. This study explored the role and molecular mechanism of circular RNA 0011292 (circ_0011292) in tumorigenesis and chemoresistance of NSCLC. Methods: The levels of circ_0011292, miR-379-5p, and tripartite motif-containing protein 65 (TRIM65) were measured by quantitative real-time polymerase chain reaction or Western blot assay. Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was monitored by flow cytometry. Cell migration and invasion were detected by transwell assay. The levels of apoptosis-related and epithelial-mesenchymal transition-related proteins were examined by Western blot. The half-inhibition concentration (IC50) of paclitaxel (PTX) was evaluated by CCK-8 assay. Xenograft model was established to analyze the effect of circ_0011292 on PTX resistance of NSCLC in vivo. The interaction among circ_0011292, miR-379-5p, and TRIM65 was verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. Results: Circ_0011292 and TRIM65 were upregulated, while miR-379-5p was downregulated in NSCLC tissues and cells. Circ_0011292 knockdown hindered NSCLC progression and enhanced PTX sensitivity of NSCLC. Circ_0011292 silencing reduced PTX resistance in vivo. Besides, miR-379-5p potentiated PTX sensitivity by targeting TRIM65. Also, circ_0011292 increased PTX resistance by sponging miR-379-5p. Conclusion: Circ_0011292 facilitated tumorigenesis and PTX resistance in NSCLC by regulating the miR-379-5p/TRIM65 axis, suggesting that circ_0011292 was a promising therapeutic target for NSCLC chemotherapy.

circNUDT21 promotes bladder cancer progression by modulating the miR-16-1-3p/MDM2/p53 axis

Bladder cancer (BC) is a common genitourinary malignancy. This study investigated the regulatory effects of an exonic circRNA, circNUDT21, in the progression of BC. The circNUDT21 level was overexpressed in BC tissues and cell lines as compared to normal controls. Overexpression and silencing of circNUDT21 promoted and inhibited, respectively, the proliferative and invasive abilities of BC cells. Mechanistical analysis showed that circNUDT21 acted as a miR-16-1-3p sponge and that MDM2 was a potential downstream target of miR-16-1-3p. We further verified that overexpression of circNUDT21 was associated with elevated MDM2 and reduced p53 expression. CircNUDT21 promoted BC progression by acting as a sponge of miR-16-1-3p to activate the miR-16-1-3p/MDM2/p53 axis. These findings suggest that circNUDT21 functions as an oncogenic circRNA and may be a potential therapy target for BC.

An update on the role of miR-379 in human disorders

miR-379 is a miRNA transcribed from the MIR379 locus on 14q32.31. This miRNA is located in an evolutionarily conserved miRNA cluster in an imprinted region that contains DLK1 and DIO3 genes. The mouse homolog of this miRNA has been shown to be under-expressed in response to glucocorticoid receptor deficiency. Moreover, miR-379 has a tumor-suppressive role in a wide variety of tissues including the brain, breast, lung, and liver. In addition to restraining cell proliferation and migration, miR-379 can suppress the epithelial-mesenchymal transition process. Abnormal expression of this miRNA implies the pathogenesis of Duchene muscular dystrophy, spinal cord injury, diabetic nephropathy, acute myocardial infarction, and premature ovarian failure. This review aims to the summarization of the role of miR-379 in neoplastic and non-neoplastic conditions.

MicroRNA 379 Regulates Klotho Deficiency-Induced Cardiomyocyte Apoptosis Via Repression of Smurf1

[Figure: see text].

MiR-379-5p aggravates experimental autoimmune uveitis in mice via the regulation of SEMA3A

Uveitis is a disease resulting in the inflammation of uveal tracts, but the factors resulting in uveitis is still obscure. Previous studies have shown that miR-379-5p was involved in the pathogenesis of several diseases, however, the role and regulatory mechanism of miR-379-5p in uveitis were unclear. In our study, we established experimental autoimmune uveitis (EAU) mouse models to explore the role of miR-379-5p in uveitis. RT-qPCR identified that miR-379-5p level was increased in serum of EAU mice. In mechanism, SEMA3A 3'UTR was proven to be directly targeted by miR-379-5p and SEMA3A expression was negatively regulated by miR-379-5p in CD4⁺ T cells. Moreover, ELISA analysis revealed that knockdown of miR-379-5p suppressed the production of inflammation cytokines including IL-17, TNF-α and IL-β in vitro. These results were reversed by SEMA3A overexpression. In addition, the reduction of Th17 cells under miR-379-5p inhibitor was neutralised by SEMA3A knockdown in vitro. Furthermore, we demonstrated that knockdown of miR-379-5p significantly reversed the increased clinical scores and inflammatory response resulting from EAU treatment and this effect was further countervailed by SEMA3A silencing. Our study suggested that miR-379-5p aggravated uveitis in EAU mice via the regulation of SEMA3A, which may provide a novel insight for uveitis treatment.

AKR1C3 decreased CML sensitivity to Imatinib in bone marrow microenvironment via dysregulation of miR-379-5p

BACKGROUND

Drug resistance is an important cause of death for most patients with chronic myeloid leukemia (CML). The bone marrow microenvironment is believed to be mainly responsible for resistance to BCR-ABL tyrosine kinase inhibitors. The mechanism involved, however, is still unclear.

METHODS

Bioinformatic analysis from GEO database of AKR1C3 was utilized to identify the AKR1C3 expression in CML cells under bone marrow microenvironment. Western blot and qPCR were performed to detect the AKR1C3 expression in two CML cell lines K562 and KU812 cultured +/- bone microenvironment derived stromal cells. CCK-8, soft agar colony assay, and Annexin V/PI assay were performed to detect the sensitivity of CML cells (K562 and KU812) to Imatinib under a gain of or loss of function of AKR1C3 treatment. The CML murine model intravenous inoculated with K562-OE-vector and K562-OE-AKR1C3 cells were established to estimate the effect of AKR1C3 inhibitor Indomethacin on Imatinib resistance. The bioinformatic analysis of miRNA databases was used to predict the potential miRNAs targeting AKR1C3. And the luciferase assay was utilized to validate the target relationship between miR-379-5p and AKR1C3. And, the soft agar colony assay and Annexin V/PI were used to validate the effect of miR-379-5p in AKR1C3 induced Imatinib resistance.

RESULTS

In present study, we investigated AKR1C3 was highly expressed in CML under bone marrow microenvironment. AKR1C3 decreased Imatinib activity in K562 and KU812 cells, while inhibition of AKR1C3 could enhance Imatinib sensitivity in vitro study. Furthermore, murine model results showed combination use of AKR1C3 inhibitor Indomethacin effectively prolong mice survival, indicating that AKR1C3 is a promising target to enhance Imatinib treatment. Mechanically, AKR1C3 was found to be suppressed by miR-379-5p, which was down-expression in bone marrow microenvironment. Besides, we found miR-379-5p could bind AKR1C3 3'UTR but not degrade its mRNA level. Further, gain of miR-379-5p rescued the imatinib resistance induced by AKR1C3 overexpression in CML cells.

CONCLUSIONS

Altogether, our study identifies a novel signaling regulation of miR-379-5p/AKR1C3/EKR axis in regulating IM resistance in CML cell, and provides a scientific base for exploring AKR1C3 as a biomarker in impeding IM resistance in CML.

LINC00665/miR-379-5p/GRP78 regulates cisplatin sensitivity in gastric cancer by modulating endoplasmic reticulum stress

Acquired resistance to cisplatin (DDP)-based chemotherapy greatly hinders the treatment of gastric cancer (GC). LINC00665 serves as an oncogene in GC. Hence, the current study was designed to investigate the regulatory effects of LINC00665 on DDP-resistance of GC. LINC00665 and miR-379-5p expression levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and Glucose regulated protein 78 (GRP78) protein level was measured by western blot assay. Interactions between LINC00665 and miR-379-5p or between miR-379-5p and GRP78 were verified by dual luciferase reporter assay. Cell counting kit 8 (CCK-8) assay and flow cytometry assay respectively determine the proliferative ability and apoptosis of GC cells. Western blot analysis was also performed to detect the protein levels of C/EBP-homologous protein (CHOP), X box binding protein (XBP1) and apoptosis-related proteins. In addition, GRP78 expression was evaluated by immunofluorescence. It was observed that the expression levels of LINC00665 and GRP78 were upregulated, and the expression level of miR-379-5p was downregulated in DDP-sensitive and DDP-resistant GC cell lines. What's more, GRP78 expression and the cell growth inhibition rates of DDP-sensitive and DDP-resistant GC cells had a negative correlation. Additionally, miR-379-5p was a target miRNA of LINC00665, and GRP78 was a target mRNA of miR-379-5p. Functional studies revealed that knockdown of LINC00665 inhibited DDP-resistant GC cell proliferation, induced apoptosis as well as suppressed Endoplasmic reticulum (ER) stress. Mechanistically, knockdown of LINC00665 downregulated GRP78 expression by strengthening miR-379-5p. LINC00665 silencing could overcome DPP-resistance of GC cells by downregulating GRP78 via sponging miR-379-5p, indicating that LINC00665 might be a potential therapeutic target for DDP- resistant GC patients.

OCT3/4 enhances tumor immune response by upregulating the TET1-dependent NRF2/MDM2 axis in bladder cancer

This study aimed to investigate the function of OCT3/4 on tumor immune escape in bladder cancer. Initially, the expression of OCT3/4, TET1, NRF2 and MDM2 was quantified in tumor tissues and cells, followed by gain- or loss-of-function studies to define their roles in cell migration, invasion and apoptosis and tumorigenicity in nude mice. Bladder cancer presented with abundant expression levels of OCT3/4, TET1, NRF2 and MDM2. We found that OCT3/4 promoted TET1 expression via binding to its promoter and that TET1 recruited MLL protein to NRF2 promoter and upregulated its expression, while NRF2 enhanced MDM2 expression. Upregulated MDM2 accelerated tumor immune escape in bladder cancer in mice. OCT3/4 knockdown suppressed the cell migration and invasion while inducing apoptosis, and consequently prevented tumor growth and immune escape in mice. Collectively, OCT3/4 may promote the progression of tumor immune escape in bladder cancer through acting as a promoter of the TET1/NRF2/MDM2 axis.

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.

miRNA profiles of canine cutaneous mast cell tumours with early nodal metastasis and evaluation as potential biomarkers

Cutaneous mast cell tumours (MCTs) are common skin neoplasms in dogs. MicroRNAs (miRNAs) are post-transcriptional regulators involved in several cellular processes, and they can function as tumour promoters or suppressors. However, the role of miRNAs in canine MCTs has not yet been elucidated. Thus, the current study aimed to characterize miRNA profiles and to assess their value as biomarkers for MCTs. miRNA expression profiles were assessed in formalin-fixed, paraffin-embedded samples by next-generation sequencing. Ten samples were MCT tissues, and 7 were healthy adjacent tissues. Nine dysregulated miRNAs (DE-miRNAs) were then validated using RT-qPCR in a larger group of MCT samples, allowing the calculation of ROC curves and performance of multiple factor analysis (MFA). Pathway enrichment analysis was performed to investigate miRNA biological functions. The results showed that the expression of 63 miRNAs (18 up- and 45 downregulated) was significantly affected in MCTs. Five DE-miRNAs, namely, miR-21-5p, miR-92a-3p, miR-338, miR-379 and miR-885, were validated by RT-qPCR. The diagnostic accuracy of a panel of 3 DE-miRNAs—miR-21, miR-379 and miR-885—exhibited increased efficiency in discriminating animals with MCTs (AUC = 0.9854) and animals with lymph node metastasis (AUC = 0.8923). Multiple factor analysis revealed clusters based on nodal metastasis. Gene Ontology and KEGG analyses confirmed that the DE-miRNAs were involved in cell proliferation, survival and metastasis pathways. In conclusion, the present study demonstrated that the miRNA expression profile is changed in the MCT microenvironment, suggesting the involvement of the altered miRNAs in the epigenetic regulation of MCTs and identifying miR-21, miR-379 and miR-885 as promising biomarkers.

Long non‑coding RNA PCAT6 promotes the development of osteosarcoma by increasing MDM2 expression

Osteosarcoma is a severe malignant tumor. Several studies indicated that lncRNA prostate cancer-associated transcript 6 (PCAT6) promoted the development of multiple types of cancers. Studies have also revealed that MDM2 could aggravate tumor symptoms inhibiting P53 expression. However, whether lncRNA PCAT6 could affect the proliferation and metastasis of osteosarcoma cells by regulating P53 expression is unclear. The present study established lncRNA PCAT6-overexpressing osteosarcoma cells. Cell Counting Kit-8, wound healing and Transwell assays were performed to detect the change in proliferation, migration and invasion of these cells, respectively. Subsequently, E3 ubiquitin-protein ligase Mdm2 (MDM2), P53 and P21 expression were determined using western blotting. Finally, MDM2 expression was inhibited and the proliferation, migration and invasion of these cells was determined again. The present study found that the proliferation, migration and invasion of osteosarcoma cells increased following overexpression of lncRNA PCAT6. MDM2 expression was upregulated while the levels of P53 and P21 decreased following overexpression of lncRNA PCAT6. However, the proliferation, migration and invasion of osteosarcoma cells were inhibited following MDM2 knockdown. Additionally, P53 and P21 was rescued following MDM2 knockdown. To conclude, lncRNA PCAT6 promoted the proliferation, migration and invasion of osteosarcoma cells by promoting the expression of MDM2 and suppressing the expression of P53 and P21.

miR‑379‑5p inhibits cell proliferation and promotes cell apoptosis in non‑small cell lung cancer by targeting β‑arrestin‑1

Lung cancer is the most common fatal type of cancer, demonstrating high incidence rates in both sexes. Therefore, it is of vital importance to devise more effective and targeted therapies to improve the treatment quality for patients. The present study aimed to determine the effects of microRNA (miR)-379-5p on cell proliferation and apoptosis, in addition to its underlying molecular mechanisms in lung cancer. Tumor and adjacent normal tissues were obtained from patients with NSCLC and transfection experiments in A549 cells were performed using miR-379-5p mimics and pcDNA3.1- β-arrestin-1 (ARRB1) overexpression plasmids. The cell proliferation rate was determined using a Cell Counting Kit-8 assay and the cell apoptotic rate was analyzed using flow cytometry. Additionally, the mRNA and protein expression levels of proliferation-related signaling (PI3K, p-PI3K, AKT and p-AKT) and apoptotic-related factors (Bcl-2, Bax and caspase-3) were detected using reverse transcription-quantitative PCR and western blotting, respectively. The results of the present study revealed that miR-379-5p expression levels were downregulated, whereas ARRB1 expression levels were significantly upregulated in NSCLC tissues and cell lines. Following the successful transfection of the miR-379-5p mimic and ARRB1 overexpression plasmid, it was revealed that the overexpression of miR-379-5p inhibited cell proliferation and promoted cell apoptosis, whereas ARRB1 overexpression reversed this inhibition over proliferation and promotion of apoptosis. The increased cell apoptotic rate observed in the miR-379-5p mimics group was associated with a significant downregulation and upregulation of Bcl-2, and Bax and caspase-3 expression levels, respectively. Finally, ARRB1 was identified as a target gene of miR-379-5p. In conclusion, the expression levels of miR-379-5p were demonstrated to be significantly downregulated in lung cancer. In addition, miR-379-5p overexpression led to the decreased expression levels of Bcl-2, phosphorylated (p)-PI3K/PI3K and p-AKT/AKT, and the increased expression levels of Bax and caspase-3. Overall, this resulted in the inhibition of cell proliferation and promoted cell apoptosis by directly targeting ARRB1. Therefore, miR-379-5p may be a potential target for NSCLC treatment due to its ability to inhibit cell proliferation and accelerate the apoptotic process.

miR-30d Induced Apoptosis by Targeting Sox4 to Inhibit the Proliferation, Invasion and Migration of Nephroblastoma

Background

Wilms tumor (WT) is an embryonic malignant tumor, and its related mechanism is still unclear. microRNA (miR), as a short-chain non-coding RNA, has low expression in various tumors. In this study, WT differential miR was screened by multi-chip in GEO database and its mechanism was explored to provide potential therapeutic targets and ideas for clinic.

Methods

We logged into GEO database and downloaded GSE57370 and GSE48137 chip matrix files to analyze potential differences in miR. TargetScan, miRDB, miRTarBase and starBase were applied to predict the target genes of miR with significant differences. qRT-PCR was applied to determine the expression of miR-30d and Sox4 in WT tissue and cell line (G401). The interaction of miR-30d with Sox4 was confirmed by qRT-PCR, Western blot and luciferase assay, respectively. CCK-8, Transwell and flow cytometry were applied to determine the proliferation, invasion, migration and apoptosis of cells.

Results

We found that miR-30d was low expressed in two chips. qRT-PCR showed that miR-30d was down-regulated and SOX4 was up-regulated in WT tissues and cells. The online target gene prediction software showed there was a targeted binding site between Sox4 and miR-30d. Sox4 was negatively controlled by miR-30d. Subsequent studies found that over-expression of miR-30d inhibited the proliferation, invasion, migration and induced apoptosis of C64 and WiT49 cells. In addition, Sox4 could reverse the proliferation, invasion and migration of C64 and WiT49 induced by miR-30d and induce apoptosis.

Conclusion

miR-30d is poorly expressed in WT and can induce apoptosis and inhibit proliferation, invasion and migration by mediating Sox4.

MicroRNA-379-5p/YBX1 Axis Regulates Cellular EMT to Suppress Migration and Invasion of Nasopharyngeal Carcinoma Cells

Background

Epithelial–mesenchymal transition (EMT) is a major actor modulating the metastasis of nasopharyngeal carcinoma (NPC). Increasing evidence indicates that microRNAs (miRs) are the important regulators of EMT program. However, the potential roles and underlying mechanisms of miR‑379-5p in regulating EMT of NPC cells remain unclear.

Methods

miR-379-5p expression levels in human NPC tissues and cell lines were detected via quantitative real-time PCR (qRT-PCR). Then, the correlations between miR-379-5p expression in NPC tissues and clinicopathologic features and patients’ prognosis were analyzed. The effect of miR-379-5p on the expression of EMT markers in NPC cells was evaluated by Western blot and qRT-PCR. NPC cells’ migration and invasion were evaluated in vitro by Transwell migration and invasion assays, respectively. The target of miR-379-5p was predicted with three publicly available databases and further validated with dual-luciferase reporter assay, qRT-PCR, and Western blot.

Results

The expression of miR-379-5p was significantly decreased in NPC tissues, and its low expression was significantly associated with multiple unfavorable clinicopathological factors and poor prognosis of NPC patients. Meanwhile, miR-379-5p was downregulated in NPC cell lines, and its exotic expression inhibited EMT to reduce the migration and invasion of NPC cells. Furthermore, Y-box binding protein 1 (YBX1) was identified and validated as a direct target of miR-379-5p, and restoring YBX1 expression could reverse the inhibitive effect of miR-379-5p on NPC cell EMT, migration and invasion.

Conclusion

Taken together, our findings indicate that miR-379-5p inhibits the EMT of NPC cells to reduce their migration and invasion abilities by post-transcriptionally suppressing YBX1 expression, providing a novel potential treatment target for NPC patients.

Homeobox B5 suppression attenuates proliferation and elevates apoptosis in hepatoma cell lines through ERK/MDM2 signalling

Homeobox B5 (HOXB5), a member of the HOX gene family, is an important gene in tumourigenesis. However, its role in hepatocellular carcinoma (HCC) cell proliferation and apoptosis remains unclear. In this study, we investigated the role and regulation mechanism of HOXB5 in HCC cell lines Hep3B and LM6. The data indicated high expression of HOXB5 in HCC tissues and cell lines. In HCC cells, inhibition of HOXB5 by transfection with HOXB5 siRNA significantly constrained cell viability, and Bcl-2 levels, and it increased cell apoptosis, cytochrome c levels, BAX levels, and caspase-3 activity. On the contrary, HOXB5 overexpression increased proliferation and Bcl-2 levels but inhibited BAX levels and caspase-3 activity in these cells. HOXB5 downregulation attenuated activation of extracellular signal-regulated kinase (ERK) and expression of the murine double minute 2 (MDM2) oncogene. Incubation with the ERK activator, phorbol 12-myristate 13-acetate (40 μmol/L), for 12 hours reversed the effects of HOXB5 inhibition on MDM2 expression, cell proliferation, and apoptosis in HCC cells. Overall, this study demonstrated that HOXB5 inhibition regulated MDM2 expression by controlling ERK activation and that it modulated proliferation and apoptosis in HCC cells.

Serum miR-379 expression is related to the development and progression of hypercholesterolemia in non-alcoholic fatty liver disease

Introduction

Non-alcoholic fatty liver disease (NAFLD) has a wide spectrum, eventually leading to cirrhosis and hepatic carcinogenesis. We previously reported that a series of microRNAs (miRNAs) mapped in the 14q32.2 maternally imprinted gene region (Dlk1-Dio3 mat) are related to NAFLD development and progression in a mouse model. We examined the suitability of miR-379, a circulating Dlk1-Dio3 mat miRNA, as a human NAFLD biomarker.

Methods

Eighty NAFLD patients were recruited for this study. miR-379 was selected from the putative Dlk1-Dio3 mat miRNA cluster because it exhibited the greatest expression difference between NAFLD and non-alcoholic steatohepatitis in our preliminary study. Real-time PCR was used to examine the expression levels of miR-379 and miR-16 as an internal control. One patient was excluded due to low RT-PCR signal.

Results

Compared to normal controls, serum miR-379 expression was significantly up-regulated in NAFLD patients. Receiver operating characteristic curve analysis suggested that miR-379 is a suitable marker for discriminating NAFLD patients from controls, with an area under the curve value of 0.72. Serum miR-379 exhibited positive correlations with alkaline phosphatase, total cholesterol, low-density-lipoprotein cholesterol and non-high-density-lipoprotein cholesterol levels in patients with early stage NAFLD (Brunt fibrosis stage 0 to 1). The correlation between serum miR-379 and cholesterol levels was lost in early stage NAFLD patients treated with statins. Software-based predictions indicated that various energy metabolism–related genes, including insulin-like growth factor-1 (IGF-1) and IGF-1 receptor, are potential targets of miR-379.

Conclusions

Serum miR-379 exhibits high potential as a biomarker for NAFLD. miR-379 appears to increase cholesterol lipotoxicity, leading to the development and progression of NAFLD, via interference with the expression of target genes, including those related to the IGF-1 signaling pathway. Our results could facilitate future research into the pathogenesis, diagnosis, and treatment of NAFLD.

MiR-219a-2-3p suppresses cell proliferation and promotes apoptosis by targeting MDM2/p53 in pituitary adenomas cells

Pituitary adenomas constitute one of the most common intracranial tumors. MicroRNAs play an important role in development and progression of pituitary adenomas. In this study, we showed that miR-219a-2-3p was significantly down-regulated in pituitary adenomas cells. Overexpression of miR-219a-2-3p suppressed the proliferation and promoted apoptosis of pituitary adenomas cells. After bioinformatics analysis, we found that MDM2 was one of the downstream targets of miR-219a-2-3p. Further researches showed that miR-219a-2-3p could reduce the protein level of MDM2 by binding to the 3'-UTR of MDM2 and promoted p53 expression. Then, we overexpressed both miR-219a-2-3p and MDM2 in the same group and found that it could counteract the effect of overexpressing miR-219a-2-3p alone on proliferation and apoptosis of pituitary adenoma cells. Taken together, these results suggested that miR-219a-2-3p regulated the proliferation and apoptosis by targeting MDM2/p53 in pituitary adenomas. Therefore, miR-219a-2-3p may serve as a novel marker and therapeutic target for pituitary adenomas.

Emerging Roles of Cancer Stem Cells in Bladder Cancer Progression, Tumorigenesis, and Resistance to Chemotherapy: A Potential Therapeutic Target for Bladder Cancer

Bladder cancer (BC) is a complex and highly heterogeneous stem cell disease associated with high morbidity and mortality rates if it is not treated properly. Early diagnosis with personalized therapy and regular follow-up are the keys to a successful outcome. Cancer stem cells (CSCs) are the leading power behind tumor growth, with the ability of self-renewal, metastasis, and resistance to conventional chemotherapy. The fast-developing CSC field with robust genome-wide screening methods has found a platform for establishing more reliable therapies to target tumor-initiating cell populations. However, the high heterogeneity of the CSCs in BC disease remains a large issue. Therefore, in the present review, we discuss the various types of bladder CSC heterogeneity, important regulatory pathways, roles in tumor progression and tumorigenesis, and the experimental culture models. Finally, we describe the current stem cell-based therapies for BC disease.

LINC00665 promotes breast cancer progression through regulation of the miR-379-5p/LIN28B axis

Breast cancer is the most common malignant tumor among women worldwide. Although increasing evidence indicates that long noncoding RNAs (lncRNAs) play critical roles during breast tumorigenesis and progression, the involvement of most lncRNAs in breast cancer remains largely unknown. In the current study, we demonstrated that LINC00665 promotes breast cancer cell proliferation, migration, and invasion. Accumulating evidence indicates that many lncRNAs can function as endogenous miRNA sponges by competitively binding common miRNAs. In this study, we demonstrated that LINC00665 functions as a sponge for miR-379-5p, reducing the ability of miR-379-5p to repress LIN28B. LINC00665 promoted breast cancer progression and induced an epithelial-mesenchymal transition-like phenotype via the upregulation of LIN28B expression. Clinically, LINC00665 expression was increased but miR-379-5p expression was decreased in breast cancer tissues compared with that in normal breast tissues in the TCGA database. Furthermore, the expression of LINC00665 was negatively related with miR-379-5p expression. Collectively, our results reveal the LINC00665-miR-379-5p-LIN28B axis and shed light on breast cancer therapy.

miR-1305 Inhibits The Progression Of Non-Small Cell Lung Cancer By Regulating MDM2

Background

Increasing evidence has suggested the critical implication of microRNAs (miRNAs) in the initiation and progression of non-small cell lung cancer (NSCLC). Previous studies have shown the tumor-suppressive function of miR-1305 in cancer; however, the role of miR-1305 in NSCLC has not been fully understood.

Methods

The expression of miR-1305 in NSCLC was detected by RT-qPCR. The influence of miR-1305 on the growth of NSCLC cells was determined via Cell Counting Kit 8 (CCK-8), colony formation and FACS analysis. The targets of miR-1305 were predicted with the miRDB database. Luciferase reporter assay was performed to investigate the binding between miR-1305 and 3ʹ-UTR of MDM2. Western blot was applied to check the expression of MDM2 with miR-1305.

Results

Here, we found that miR-1305 was down-regulated in NSCLC tissues and cell lines. Decreased miR-1305 was significantly correlated with the metastasis and poor prognostics of NSCLC patients. Overexpression of miR-1305 inhibited the proliferation and migration and promoted the apoptosis of NSCLC cells. Bioinformatics and luciferase assay uncovered that the mouse/murine double minute 2 (MDM2) was a target of miR-1305. miR-1305 bound the 3ʹ-untranslated region (UTR) of MDM2 and decreased the expression of MDM2 in NSCLC cells. As MDM2 was a negative regulator of p53, decreased MDM2 by miR-1305 up-regulated the abundance of p53 in NSCLC cells. Restoration of MDM2 markedly attenuated the suppressive role of miR-1305 in the proliferation and migration of NSCLC cells.

Conclusion

The findings provided novel mechanism of miR-1305/MDM2 signaling in regulating the progression of NSCLC, suggesting miR-1305 as a promising target for the treatment of NSCLC.

Clustering analysis of microRNA and mRNA expression data from TCGA using maximum edge-weighted matching algorithms

Background

microRNA (miRNA) is a short RNA (~ 22 nt) that regulates gene expression at the posttranscriptional level. Aberration of miRNA expressions could affect their targeting mRNAs involved in cancer-related signaling pathways. We conduct clustering analysis of miRNA and mRNA using expression data from the Cancer Genome Atlas (TCGA). We combine the Hungarian algorithm and blossom algorithm in graph theory. Data analysis is done using programming language R and Python.

Methods

We first quantify edge-weights of the miRNA-mRNA pairs by combining their expression correlation coefficient in tumor (T_CC) and correlation coefficient in normal (N_CC). We thereby introduce a bipartite graph partition procedure to identify cluster candidates. Specifically, we propose six weight formulas to quantify the change of miRNA-mRNA expression T_CC relative to N_CC, and apply the traditional hierarchical clustering to subjectively evaluate the different weight formulas of miRNA-mRNA pairs. Among these six different weight formulas, we choose the optimal one, which we define as the integrated mean value weights, to represent the connections between miRNA and mRNAs. Then the Hungarian algorithm and the blossom algorithm are employed on the miRNA-mRNA bipartite graph to passively determine the clusters. The combination of Hungarian and the blossom algorithms is dubbed maximum weighted merger method (MWMM).

Results

MWMM identifies clusters of different sizes that meet the mathematical criterion that internal connections inside a cluster are relatively denser than external connections outside the cluster and biological criterion that the intra-cluster Gene Ontology (GO) term similarities are larger than the inter-cluster GO term similarities. MWMM is developed using breast invasive carcinoma (BRCA) as training data set, but can also applies to other cancer type data sets. MWMM shows advantage in GO term similarity in most cancer types, when compared to other algorithms.

Conclusions

miRNAs and mRNAs that are likely to be affected by common underlying causal factors in cancer can be clustered by MWMM approach and potentially be used as candidate biomarkers for different cancer types and provide clues for targets of precision medicine in cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0562-z) contains supplementary material, which is available to authorized users.

Somatic Mutations in miRNA Genes in Lung Cancer-Potential Functional Consequences of Non-Coding Sequence Variants

A growing body of evidence indicates that miRNAs may either drive or suppress oncogenesis. However, little is known about somatic mutations in miRNA genes. To determine the frequency and potential consequences of miRNA gene mutations, we analyzed whole exome sequencing datasets of 569 lung adenocarcinoma (LUAD) and 597 lung squamous cell carcinoma (LUSC) samples generated in The Cancer Genome Atlas (TCGA) project. Altogether, we identified 1091 somatic sequence variants affecting 522 different miRNA genes and showed that half of all cancers had at least one such somatic variant/mutation. These sequence variants occurred in most crucial parts of miRNA precursors, including mature miRNA and seed sequences. Due to our findings, we hypothesize that seed mutations may affect miRNA:target interactions, drastically changing the pool of predicted targets. Mutations may also affect miRNA biogenesis by changing the structure of miRNA precursors, DROSHA and DICER cleavage sites, and regulatory sequence/structure motifs. We identified 10 significantly overmutated hotspot miRNA genes, including the miR-379 gene in LUAD enriched in mutations in the mature miRNA and regulatory sequences. The occurrence of mutations in the hotspot miRNA genes was also shown experimentally. We present a comprehensive analysis of somatic variants in miRNA genes and show that some of these genes are mutational hotspots, suggesting their potential role in cancer.

MicroRNA‑663b downregulation inhibits proliferation and induces apoptosis in bladder cancer cells by targeting TUSC2

The present study aimed to explore the role and underlying molecular mechanism of microRNA‑663b (miR‑663b) in the tumorigenesis of bladder cancer. The miR‑663b expression in human bladder cancer tissues and cell lines was measured determined reverse transcription‑quantitative polymerase chain reaction. TargetScan was used to predict the potential targets of miR‑663b, and a dual‑luciferase reporter assay was performed to validate tumor suppressor candidate 2 (TUSC2) as a target of miR‑663b. Cell Counting Kit‑8 was used for cell viability analysis, and cell apoptosis was evaluated by flow cytometry. In addition, western blot analysis was performed to detect protein expression in current study. The findings suggested that miR‑663b was upregulated in bladder cancer tissues and cell lines compared with normal tissue and cells. TUSC2 was validated as a direct target of miR‑663b and was negatively regulated by miR‑663b. miR‑663b inhibition significantly reduced the viability of T24 cells, and T24 cell apoptosis was markedly induced. In addition, miR‑663b inhibition enhanced the expression levels of p53 and p21 in T24 cells. Furthermore, the changes caused by miR‑663b inhibitor in T24 cells were eliminated by TUSC2 gene silencing. In conclusion, inhibition of miR‑663b reduced viability and induced apoptosis in bladder cancer cells by targeting TUSC2. These findings provide a promising novel therapeutic target for bladder cancer treatment.

Integrated Analysis of miRNA and mRNA Expression Profiles Reveals Functional miRNA-Targets in Development Testes of Small Tail Han Sheep

Small Tail Han Sheep is a highly valued local breed in China because of their precocity, perennial estrus, and high fecundity. The average annual lambing rate of ewes is as high as 180–270%, the semen of ram has characteristics of high yield, high density, and good motility. To reveal the key miRNAs and miRNA-targets underlying testis development and spermatogenesis in male Small Tail Han Sheep, integrated analysis of miRNA and mRNA expression profiles in 2-, 6-, and 12-month-old testes was performed by RNA-seq technology and bioinformatics methods. The results showed that total of 153 known sheep miRNAs and 2712 novel miRNAs were obtained in 2-,6 - and 12-month-old Small Tail Han Sheep testes; 5, 1, and 4 differentially expressed (DE) known sheep miRNAs, and 132, 105, and 24 DE novel miRNAs were identified in 2- vs. 6-, 6- vs. 12-, and 2- vs. 12-month-old testes, respectively. We combined miRNA results of this study and the mRNA results obtained in our previous study to predict the target mRNAs of DE known sheep miRNAs; 131, 10, and 15 target mRNAs of DE known sheep miRNAs and 76, 1, and 11 DE miRNA–targets were identified in the three groups, respectively. GO and KEGG analyses showed that: in 2- vs. 6-month-olds, the target genes of DE known sheep miRNAs were involved in 100 biological processes and 11 signaling pathways; in 6- vs. 12-month-olds, the target genes of DE known sheep miRNAs were involved in 4 biological processes; and in 2- vs. 12-month-olds, the target genes of DE known sheep miRNAs were involved in 17 biological processes and 4 signaling pathways. Three miR–target regulatory networks were constructed based on these DE miRNA–targets. The key miRNA-Targets involved in testis development and spermatogenesis were screened. 6 known sheep miRNAs and 6 novel miRNAs were selected to validate the accuracy of miRNA sequencing data by qRT-PCR. The binding sites of oar-miR-379-5p with WNT8A was validated by a dual luciferase reporter gene detection system.

Dysregulation of ncRNAs located at the DLK1‑DIO3 imprinted domain: involvement in urological cancers

Genomic imprinting has been found to be involved in human physical development and several diseases. The DLK1-DIO3 imprinted domain is located on human chromosome 14 and contains paternally expressed protein-coding genes (DLK1, RTL1, DIO3) and numerous maternally expressed ncRNA genes (MEG3, MEG8, antisense RTL1, miRNAs, piRNAs, and snoRNAs). Emerging evidence has implicated that dysregulation of the DLK1-DIO3 imprinted domain especially the imprinted ncRNAs is critical for tumor progressions. Multiple miRNAs and lncRNAs have been investigated in urological cancers, of which several are transcribed from this domain. In this review, we present current data about the associated miRNAs, lncRNAs, and piRNAs and the regulation of differentially methylated regions methylation status in the progression of urological cancers and preliminarily propose certain concepts about the potential regulatory networks involved in DLK1-DIO3 imprinted domain.

Tumor-suppressing effects of microRNA-612 in bladder cancer cells by targeting malic enzyme 1 expression

The present study investigated the possible tumor-suppressing function of microRNA (miR)-612 and the underlying molecular mechanism of its action in bladder cancer in vitro and in vivo. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was carried out to quantify the expression levels of miR-612 in bladder cancer tissues and cell lines. The data demonstrated that the level of miR-612 expression was significantly reduced in bladder cancer tissues and cell lines, as compared with that in non-cancerous tissues and cells. Reduced miR-612 expression was associated with advanced tumor, lymph node and metastasis stages, and with distant metastasis of bladder cancer. A functional study revealed that transfection of cells with an miR-612 mimic suppressed bladder cancer cell growth, colony formation, migration, invasion and epithelial-mesenchymal transition. Bioinformatics analysis identified that miR-612 targeted the expression of malic enzyme 1 (ME1), and this was confirmed by western blot and luciferase reporter assay results. Furthermore, the ME1 expression levels were inversely associated with miR-612 expression in bladder cancer tissue specimens. In addition, knockdown of ME1 expression using ME1 siRNA mimicked the effect of ectopic miR-612 overexpression in bladder cancer cells in terms of tumor cell growth, migration and invasion. By contrast, ME1 overexpression weakened the inhibitory effect of the miR-612 mimic in bladder cancer cells. In conclusion, the present study demonstrated that miR-612 may function as a tumor suppressor in bladder cancer by targeting ME1 expression.

Friend or Foe: MicroRNAs in the p53 network

The critical tumor suppressor gene TP53 is either lost or mutated in more than half of human cancers. As an important transcriptional regulator, p53 modulates the expression of many microRNAs. While wild-type p53 uses microRNAs to suppress cancer development, microRNAs that are activated by gain-of-function mutant p53 confer oncogenic properties. On the other hand, the expression of p53 is tightly controlled by a fine-tune machinery including microRNAs. MicroRNAs can target the TP53 gene directly or other factors in the p53 network so that expression and function of either the wild-type or the mutant forms of p53 is downregulated. Therefore, depending on the wild-type or mutant p53 context, microRNAs contribute substantially to suppress or exacerbate tumor development.

MicroRNA-379 Suppresses Cervical Cancer Cell Proliferation and Invasion by Directly Targeting V-crk Avian Sarcoma Virus CT10 Oncogene Homolog-Like (CRKL)

Cervical cancer is the fourth most common malignancy among females worldwide. MicroRNA-379 (miR-379) is aberrantly expressed in multiple human cancer types. However, the expression pattern, roles, and detailed regulatory mechanisms of miR-379 in cervical cancer remain unknown. In this study, we found that miR-379 expression was downregulated in cervical cancer tissues and cell lines. Low miR-379 expression was correlated with International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and distant metastasis. Additionally, miR-379 overexpression suppressed the proliferation and invasion of cervical cancer cells. Furthermore, V-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) was identified as a direct target of miR-379 in cervical cancer. CRKL was upregulated in cancer tissues and negatively correlated with miR-379 expression. Moreover, restored CRKL expression rescued the inhibitory effects of miR-379 overexpression on cell proliferation and invasion. In conclusion, miR-379 may serve as a tumor suppressor in cervical cancer by directly targeting CRKL. Restoring miR-379 expression may be an effective strategy for the treatment of cervical cancer.

MicroRNA-379 inhibits cell proliferation and invasion in glioma via targeting metadherin and regulating PTEN/AKT pathway

Numerous microRNAs (miRNAs) are aberrantly expressed in glioma, and implicated in glioma occurrence and development. Therefore, the development of miRNAs as potential therapeutic targets for the treatment of patients with glioma has been proposed. miR‑379 has been shown to be aberrantly expressed in the progression of malignant tumours. However, the expression, biological functions and mechanism of miR‑379 in glioma are yet to be fully understood. Hence, the present study aimed to detect miR‑379 expression, investigate its functional relevance and explore its associated molecular mechanism in glioma. In this study, miR‑379 expression was significantly downregulated in glioma tissues and cell lines. Enforced miR‑379 expression markedly suppressed the cell proliferation and invasion of glioma. Metadherin (MTDH) was identified as a direct target of miR‑379 in glioma. The miR‑379 expression and MTDH mRNA levels exhibited an inverse association in glioma tissues. The restoration of the MTDH expression partially rescued the inhibitory effects of miR‑379 overexpression on glioma cell proliferation and invasion, and the upregulation of miR‑379 inhibited the activation of phosphatase and tensin homolog (PTEN)/AKT serine/threonine kinase (AKT) signaling pathway. Overall, these findings demonstrated that miR‑379 may play tumour‑suppressing roles in glioma through downregulation of MTDH and regulation of the PTEN/AKT signaling pathway, suggesting that miR‑379 might be a possible target for the treatment of patients with this malignancy.

Reduced levels of methyltransferase DNMT2 sensitize human fibroblasts to oxidative stress and DNA damage that is accompanied by changes in proliferation-related miRNA expression

Methyltransferase DNMT2 is suggested to be involved in the regulation of numerous processes, however its biological significance and underlying molecular mechanisms remain elusive. In the present study, we have used WI-38 and BJ human fibroblasts as an in vitro model system to investigate the effects of siRNA-based DNMT2 silencing. DNMT2-depleted cells were found to be sensitive to oxidative stress conditions as judged by increased production of reactive oxygen species and susceptible to DNA damage that resulted in the inhibition of cell proliferation. DNMT2 silencing promoted upregulation of proliferation-related and tumor suppressor miRNAs, namely miR-28-3p, miR-34a-3p, miR-30b-5p, miR-29b-3p, miR-200c-3p, miR-28-5p, miR-379-5p, miR-382-5p, miR-194-5p, miR-193b-3p and miR-409-3p. Moreover, DNMT2 silencing induced cellular senescence and DNMT2 levels were elevated in replicatively senescent cells. Taken together, we found that DNMT2 may take part in the regulation of cell proliferation and longevity in human fibroblasts and speculate that the manipulation of DNMT2 levels that limits cell proliferation may be potentially useful anticancer strategy.

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DNMT2 silencing promotes oxidative stress and DNA damage in human fibroblasts.

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DNMT2 silencing results in upregulation of proliferation-related miRNAs.

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DNMT2 silencing inhibits cell proliferation and induces cellular senescence.

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DNMT2 levels are elevated during replicative senescence.

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DNMT2 is a novel regulator of cell proliferation and longevity in human fibroblasts.