Mir-135a enhances cellular proliferation through post-transcriptionally regulating PHLPP2 and FOXO1 in human bladder cancer

Bladder cancer: non-coding RNAs and exosomal non-coding RNAs

Bladder cancer (BCa) is a highly prevalent type of cancer worldwide, and it is responsible for numerous deaths and cases of disease. Due to the diverse nature of this disease, it is necessary to conduct significant research that delves deeper into the molecular aspects, to potentially discover novel diagnostic and therapeutic approaches. Lately, there has been a significant increase in the focus on non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), due to their growing recognition for their involvement in the progression and manifestation of BCa. The interest in exosomes has greatly grown due to their potential for transporting a diverse array of active substances, including proteins, nucleic acids, carbohydrates, and lipids. The combination of these components differs based on the specific cell and its condition. Research indicates that using exosomes could have considerable advantages in identifying and forecasting BCa, offering a less invasive alternative. The distinctive arrangement of the lipid bilayer membrane found in exosomes is what makes them particularly effective for administering treatments aimed at managing cancer. In this review, we have tried to summarize different ncRNAs that are involved in BCa pathogenesis. Moreover, we highlighted the role of exosomal ncRNAs in BCa.

miR-133a and miR-135a Regulate All-Trans Retinoic Acid-Mediated Differentiation in Pediatric Acute Myeloid Leukemia by Inhibiting CDX2 Translation and Serve as Prognostic Biomarkers

Background: Acute myeloid leukemia (AML) is a type of blood cancer characterized by excessive growth of immature myeloid cells. Unfortunately, the prognosis of pediatric AML remains unfavorable. It is imperative to further our understanding of the mechanisms underlying leukemogenesis and explore innovative therapeutic approaches to enhance overall disease outcomes for patients with this condition. Methods: Quantitative reverse-transcription PCR was used to quantify the expression levels of microRNA (miR)-133a and miR-135a in 68 samples from 59 pediatric patients with AML. Dual-luciferase reporter transfection assay, Cell Counting Kit-8 assay, and western blot analysis were used to investigate the functions of miR-133a and miR-135a. Results: Our study found that all-trans-retinoic acid (ATRA) promoted the expression of miR-133a and miR-135a in AML cells, inhibited caudal type homeobox 2 (CDX2) expression, and subsequently inhibited the proliferation of AML cells. Additionally, miR-133a and miR-135a were highly expressed in patients with complete remission and those with better survival. Conclusions: miR-133a and miR-135a may play an antioncogenic role in pediatric AML through the ATRA-miRNA133a/135a-CDX2 pathway. They hold promise as potentially favorable prognostic indicators and novel therapeutic targets for pediatric AML.

CircSTK39 suppresses the proliferation and invasion of bladder cancer by regulating the miR-135a-5p/NR3C2-mediated epithelial-mesenchymal transition signaling pathway

Circular RNAs (circRNAs) serve as novel noncoding RNAs that have crucial functions in the development of tumors, including those from bladder cancer (BCa). However, the role and underlying molecular mechanism of circRNAs in mediating the epithelial-mesenchymal transition (EMT) processes in BCa have yet to be studied. In this research, we first found a novel circRNA, circSTK39 (termed as has_circ_0001079), which was a downregulated gene based on the results of high-throughput RNA sequencing. Subsequently, we determined that the expression of circSTK39 in BCa tissues and their cell lines was significantly reduced. In addition, lower circSTK39 expression was strongly related to a worse prognosis for BCa patients. Next, we detected the biological functions of circSTK39 by using loss and gain experiments in vitro and in vivo. Ectopic expression of circSTK39 decreased cell proliferation, colony formation, and invasion capacities, while circSTK39 knockdown prevented the above phenotypes. Mechanically, circSTK39 could sponge with miR-135a-5p, thus inhibiting NR3C2-mediated EMT processes in the BCa progression. In conclusion, our results revealed that circSTK39 inhibited EMT of BCa cells through the miR-135a-5p/NR3C2 axis and may provide promising biomarkers for the diagnosis or prospective therapeutic targets for BCa.

MicroRNAs as master regulators of FOXO transcription factors in cancer management

MicroRNAs are critical regulators of the plethora of genes, including FOXO "forkhead" dependent transcription factors, which are bonafide tumour suppressors. The FOXO family members modulate a hub of cellular processes like apoptosis, cell cycle arrest, differentiation, ROS detoxification, and longevity. Aberrant expression of FOXOs in human cancers has been observed due to their down-regulation by diverse microRNAs, which are predominantly involved in tumour initiation, chemo-resistance and tumour progression. Chemo-resistance is a major obstacle in cancer treatment. Over 90% of casualties in cancer patients are reportedly associated with chemo-resistance. Here, we have primarily discussed the structure, functions of FOXO and also their post-translational modifications which influence the activities of these FOXO family members. Further, we have addressed the role of microRNAs in carcinogenesis by regulating the FOXOs at post-transcriptional level. Therefore, microRNAs-FOXO axis can be exploited as a novel cancer therapy. The administration of microRNA-based cancer therapy is likely to be beneficial to curb chemo-resistance in cancers.

Pan-cancer onco-signatures reveal a novel mitochondrial subtype of luminal breast cancer with specific regulators

BACKGROUND

Somatic alterations in cancer cause dysregulation of signaling pathways that control cell-cycle progression, apoptosis, and cell growth. The effect of individual alterations in these pathways differs between individual tumors and tumor types. Recognizing driver events is a complex task requiring integrating multiple molecular data, including genomics, epigenomics, and functional genomics. A common hypothesis is that these driver events share similar effects on the hallmarks of cancer. The availability of large-scale multi-omics studies allows for inferring these common effects from data. Once these effects are known, one can then deconvolve in every individual patient whether a given genomics alteration is a driver event.

METHODS

Here, we develop a novel data-driven approach to identify shared oncogenic expression signatures among tumors. We aim to identify gene onco-signature for classifying tumor patients in homogeneous subclasses with distinct prognoses and specific genomic alterations. We derive expression pan-cancer onco-signatures from TCGA gene expression data using a discovery set of 9107 primary pan-tumor samples together with respective matched mutational data and a list of known cancer-related genes from COSMIC database.

RESULTS

We use the derived ono-signatures to state their prognostic significance and apply them to the TCGA breast cancer dataset as proof of principle of our approach. We uncover a "mitochondrial" sub-group of Luminal patients characterized by its biological features and regulated by specific genetic modulators. Collectively, our results demonstrate the effectiveness of onco-signatures-based methodologies, and they also contribute to a comprehensive understanding of the metabolic heterogeneity of Luminal tumors.

CONCLUSIONS

These findings provide novel genomics evidence for developing personalized breast cancer patient treatments. The onco-signature approach, demonstrated here on breast cancer, is general and can be applied to other cancer types.

HYOU1 promotes cell proliferation, migration, and invasion via the PI3K/AKT/FOXO1 feedback loop in bladder cancer

BACKGROUND

Hypoxia up-regulated 1 (HYOU1) was identified as a proto-oncogene and involved in tumorigenesis and progression in several cancer. Nonetheless, the biological function and mechanism of HYOU1 in bladder cancer (BCa) remian unclear.

METHODS

The HYOU1 level in BCa tissues and cells was examined using RT-qPCR and western blot methods. The relationship between HYOU1 expression and clinicopathologic characteristics of BCa was analyzed. The biological role of HYOU1 on BCa cell proliferation, apoptosis, migration and invasion were analyzed via counting kit-8 (CCK-8), flow cytometry, wound healing and Transwell assays, respectively. The association between HYOU1 and the PI3K/AKT/Forkhead box O1 (FOXO1) signalling was assessed via western blot assay, meanwhile the the association of FOXO1 with HYOU1 was also investigated.

RESULTS

HYOU1 was up-regulated in BCa tissues and cell lines, and the high level of HYOU1 was associated with bladder cancer histological grade and pathologic stage. Moreover, patients with high expression of HYOU1 showed poor overall survival from Kaplan-Meier Plotter. HYOU1 depletion impeded cell proliferation, migration and invasion, and induced cell apoptosis, while HYOU1 overexpression promoted cell proliferation, migration and invasion. Mechanically, our results showed that HYOU1 knockdown repressed PI3K/AKT/FOXO1 pathway and HYOU1 was negative regulated by FOXO1 in BCa. Significantly, we confirmed that the HYOU1/PI3K-AKT/FOXO1 negative feedback loop was involved in BCa cell proliferation, migration and invasion.

CONCLUSION

These findings revealed that HYOU1 acted as a pro-oncogene on BCa progression, and it will be a possible target for BCa treatment.

RSK2 promotes melanoma cell proliferation and vemurafenib resistance via upregulating cyclin D1

BRAF inhibitors are commonly used in targeted therapies for melanoma patients harboring BRAF^V600E mutant. Despite the benefit of vemurafenib therapy, acquired resistance during or after treatment remains a major obstacle in BRAF^V600E mutant melanoma. Here we found that RSK2 is overexpressed in melanoma cells and the high expression of RSK2 indicates poor overall survival (OS) in melanoma patients. Overexpression of RSK2 leads to vemurafenib resistance, and the deletion of RSK2 inhibits cell proliferation and sensitizes melanoma cells to vemurafenib. Mechanistically, RSK2 enhances the phosphorylation of FOXO1 by interacting with FOXO1 and promoting its subsequent degradation, leading to upregulation of cyclin D1 in melanoma cells. These results not only reveal the presence of a RSK2-FOXO1-cyclin D1 signaling pathway in melanoma, but also provide a potential therapeutic strategy to enhance the efficacy of vemurafenib against cancer.

A review on the importance of miRNA-135 in human diseases

MicroRNA-135 (miR-135) is a microRNA which is involved in the pathoetiology of several neoplastic and non-neoplastic conditions. Both tumor suppressor and oncogenic roles have been reported for this miRNA. Studies in prostate, renal, gallbladder and nasopharyngeal cancers as well as glioma have shown down-regulation of miR-135 in cancerous tissues compared with controls. These studies have also shown the impact of miR-135 down-regulation on enhancement of cell proliferation and aggressive behavior. Meanwhile, miR-135 has been shown to be up-regulated in bladder, oral, colorectal and liver cancers. Studies in breast, gastric, lung and pancreatic cancers as well as head and neck squamous cell carcinoma have reported dual roles for miR-135. Dysregulation of miR-135 has also been noted in various non-neoplastic conditions such as Alzheimer’s disease, atherosclerosis, depression, diabetes, Parkinson, pulmonary arterial hypertension, nephrotic syndrome, endometriosis, epilepsy and allergic conditions. In the current review, we summarize the role of miR-135 in the carcinogenesis as well as development of other disorders.

MiR-135a-5p suppresses trophoblast proliferative, migratory, invasive, and angiogenic activity in the context of unexplained spontaneous abortion

BACKGROUND

Spontaneous abortions (SA) is amongst the most common complications associated with pregnancy in humans, and the underlying causes cannot be identified in roughly half of SA cases. We found miR-135a-5p to be significantly upregulated in SA-associated villus tissues, yet the function it plays in this context has yet to be clarified. This study explored the function of miR-135a-5p and its potential as a biomarker for unexplained SA.

METHOD

RT-qPCR was employed for appraising miR-135a-5p expression within villus tissues with its clinical diagnostic values being assessed using ROC curves. The effects of miR-135a-5p in HTR-8/SVneo cells were analyzed via wound healing, Transwell, flow cytometry, EdU, CCK-8, and tube formation assays. Moreover, protein expression was examined via Western blotting, and interactions between miR-135a-5p and PTPN1 were explored through RIP-PCR, bioinformatics analyses and luciferase reporter assays.

RESULTS

Relative to normal pregnancy (NP), villus tissue samples from pregnancies that ended in unexplained sporadic miscarriage (USM) or unexplained recurrent SA (URSA) exhibited miR-135a-5p upregulation. When this miRNA was overexpressed in HTR-8/SVneo cells, their migration, proliferation, and cell cycle progression were suppressed, as were their tube forming and invasive activities. miR-135a-5p over-expression also downregulated the protein level of cyclins, PTPN1, MMP2 and MMP9. In RIP-PCR assays, the Ago2 protein exhibited significant miR-135a-5p and PTPN1 mRNA enrichment, and dual-luciferase reporter assays indicated PTPN1 to be a bona fide miR-135a-5p target gene within HTR-8/SVneo cells.

CONCLUSION

miR-135a-5p may suppress trophoblast migratory, invasive, proliferative, and angiogenic activity via targeting PTPN1, and it may thus offer value as a biomarker for unexplained SA.

miR-135a Targets SMAD2 to Promote Osteosarcoma Proliferation and Migration

Osteosarcoma (OS) is an aggressive malignant neoplasm that commonly occurs in adults and adolescents. The objectives of this work were to verify the role of microRNA- (miR-) 135a in OS and determine whether it can regulate the growth and cellular migration of OS by targeting mothers against decapentaplegic homolog 2 (SMAD2). miR-135a and SMAD2 mRNA expression levels were measured using reverse transcription-quantitative PCR (RT-qPCR). Proliferation and migration of cells were studied using the Cell Counting Kit-8, EdU staining, and transwell invasion experiment. Additionally, a dual-luciferase reporter experiment was used to investigate the possible relationship between miR-135a and SMAD2's 3'-UTR. Immunohistochemistry was utilized to examine the expressions of SMAD2 and Ki67 in mouse tumor tissues to determine the influence of miR-135a on cancer progression in vivo. miR-135a was shown to be elevated in OS tissue samples as well as five cell lines. High expression levels of miR-135a were correlated with poor prognosis of OS patients. Cellular proliferation and migration were promoted by the upregulation of miR-135a with miR mimics; however, this effect was inhibited by SMAD2 overexpression. miR-135a was also shown to directly target the 3'-UTR of SMAD2. Animal experiments also demonstrated that miR-135a downregulation had an inhibitory effect on tumor growth in vivo. High expression levels of miR-135a promoted transplanted tumor development in vivo and the proliferation and migration of OS cells by targeting SMAD2. In summary, miR-135a may be a prospective therapeutic target for OS in the future.

Hepatitis B core antigen modulates exosomal miR-135a to target vesicle-associated membrane protein 2 promoting chemoresistance in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The association of hepatitis B virus (HBV) infection with HCC is hitherto documented. Exosomal miRNAs contribute to cancer progression and chemoresistance. HBV X protein has been known to modulate miRNAs that facilitate cell proliferation and the process of hepatocarcinogenesis. However, there has been no report on hepatitis B core antigen (HBc) regulating exosomal miRNAs to induce drug resistance of HCC cells.

AIM

To elucidate the mechanism by which HBc promotes Doxorubicin hydrochloride (Dox) resistance in HCC.

METHODS

Exosomes were isolated by ultracentrifugation. The morphology and size of exosomes were evaluated by Dynamic Light Scattering (DLS) and transmission electron microscopy (TEM). The miRNAs differentially expressed in HCC were identified using The Cancer Genome Atlas (TCGA) database. The level of miR-135a-5p in patient tissue samples was detected by quantitative polymerase chain reaction. TargetScan and luciferase assay were used to predict and prove the target gene of miR-135a-5p. Finally, we identified the effects of miR-135a-5p on anti-apoptosis and the proliferation of HCC in the presence or absence of Dox using flow cytometry, Cell counting kit 8 (CCK-8) assay and western blot.

RESULTS

We found that HBc increased the expression of exosomal miR-135a-5p. Integrated analysis of bioinformatics and patient samples found that miR-135a-5p was increased in HCC tissues in comparison with paracancerous tissues. Bioinformatic analysis and in vitro validation identified vesicle-associated membrane protein 2 (VAMP2) as a novel target gene of miR-135a-5p. Functional assays showed that exosomal miR-135a-5p induced apoptosis protection, cell proliferation, and chemotherapy resistance in HCC. In addition, the rescue experiment demonstrated that VAMP2 reversed apoptosis protection, cell growth, and drug resistance by miR-135a-5p. Finally, HBc promoted HCC anti-apoptosis, proliferation, and drug resistance and prevented Dox-induced apoptosis via the miR-135a-5p/VAMP2 axis.

CONCLUSION

These data suggested that HBc upregulated the expression of exosomal miR-135a-5p and promoted anti-apoptosis, cell proliferation, and chemical resistance through miR-135a-5p/VAMP2. Thus, our work indicated an essential role of the miR-135a-5p/VAMP2 regulatory axis in chemotherapy resistance of HCC and a potential molecular therapeutic target for HCC.

MicroRNA-135a expression is upregulated in hepatocellular carcinoma and targets long non-coding RNA TONSL-AS1 to suppress cell proliferation

Dysregulation of long non-coding RNAs (lncRNAs) results in development of human diseases, including hepatocellular carcinoma (HCC). lncRNA TONSL-AS1 has been reported to act as a tumor suppressor in gastric cancer. The present study aimed to investigate the role of TONSL-AS1 in hepatocellular carcinoma (HCC). Reverse transcription-quantitative PCR analysis was performed to detect the expression levels of TONSL-AS1 and microRNA (miRNA/miR)-135a in HCC tissues and paired adjacent normal tissues. A 5-year follow-up study was performed to determine the prognostic value of TONSL-AS1 in HCC. The association between miR-135a and TONSL-AS1 was assessed via overexpression experiments. The Cell Counting Kit-8 assay was performed to assess cell proliferation. The results demonstrated that TONSL-AS1 expression was downregulated in HCC tissues, which was associated with a lower survival rate in patients with HCC. TONSL-AS1 and miR-135a were predicted to interact with each other, whereby overexpression of miR-135a downregulated TONSL-AS1 expression. The results demonstrated that TONSL-AS1 and miR-135a were inversely correlated with each other. Notably, overexpression of TONSL-AS1 inhibited HCC cell proliferation, while overexpression of miR-135a promoted HCC cell proliferation and decreased the effect of overexpression of TONSL-AS1 on cell proliferation. Taken together, the results of the present study suggest that miR-135a expression is upregulated in HCC and targets lncRNA TONSL-AS1 to suppress cell proliferation.

MicroRNA-629 promotes the tumorigenesis of non-small-cell lung cancer by targeting FOXO1 and activating PI3K/AKT pathway

OBJECTIVE

MicroRNA-629 (miR-629) has been found to play an important role in the pathogenesis of human cancers. However, the function of miR-629 is still unknown in non-small-cell lung cancer (NSCLC). The purpose of this study is to preliminarily elucidate the regulatory mechanism of miR-629 in NSCLC.

MATERIALS AND METHODS

The mRNA and protein expression was measured by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The function of miR-629 was investigated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and Transwell assays. The relationship between miR-629 and FOXO1 was confirmed by dual luciferase assay.

RESULTS

MiR-629 was upregulated in NSCLC tissues and cells. High expression of miR-629 predicted poor prognosis in patients with NSCLC. Moreover, miR-629 promoted cell proliferation, migration and invasion in NSCLC cells. In addition, FOXO1 was confirmed as a direct target of miR-629 in NSCLC. Furthermore, knockdown of FOXO1 also promoted proliferation, migration and invasion of NSCLC cells. More importantly, overexpression of FOXO1 weakened the carcinogenesis of miR-629 in NSCLC. Besides that, miR-629 promoted EMT and activated the PI3K/AKT pathway in NSCLC.

CONCLUSIONS

MiR-629 promotes the progression of NSCLC by targeting FOXO1 and regulating EMT/PI3K/AKT pathway.

miR‑135a‑5p inhibits tumor invasion by targeting ANGPT2 in gallbladder cancer

Gallbladder cancer (GBC) is the most aggressive cancer type in the biliary tract, and our previous studies observed that microRNA (miR)-135a-5p expression was downregulated in GBC tissues. However, few studies have focused on the mechanism of action of the miR-135a-5p target genes in GBC. The present study aimed to investigate the regulatory role of miR-135a-5p signaling in GBC. The present study found that miR-135a-5p expression was downregulated in GBC tissue, as detected by immunohistochemistry and reverse transcription-quantitative PCR. In addition, overexpression of miR-135a-5p significantly inhibited the proliferation and migration of GBC-SD cells. Using a luciferase activity assay, it was identified that angiopoietin-2 (ANGPT2) was a potential target gene of miR-135a-5p in GBC. Knockdown of ANGPT2 expression significantly inhibited the proliferation and invasion of GBC-SD cells. In conclusion, the present results suggested that miR-135a-5p affected GBC cell proliferation and invasion by targeting ANGPT2. Moreover, miR-135a-5p may be a potential biomarker for GBC progression and a potential target for GBC therapeutic intervention.

Modulation of Immune Response to Chlamydia muridarum by Host miR-135a

Previously, our laboratory established the role of small, noncoding RNA species, i.e., microRNA (miRNA) including miR-135a in anti-chlamydial immunity in infected hosts. We report here chlamydial infection results in decreased miR-135a expression in mouse genital tissue and a fibroblast cell line. Several chemokine and chemokine receptor genes (including CXCL10, CCR5) associated with chlamydial pathogenesis were identified in silico to contain putative miR-135a binding sequence(s) in the 3' untranslated region. The role of miR-135a in the host immune response was investigated using exogenous miR-135a mimic to restore the immune phenotype associated with decreased miR-135a following Chlamydia muridarum (Cm) infection. We observed miR-135a regulation of Cm-primed bone marrow derived dendritic cells (BMDC) via activation of Cm-immune CD4⁺ T cells for clonal expansion and CCR5 expression. Using a transwell cell migration assay, we explore the role of miR-135a in regulation of genital tract CXCL10 expression and recruitment of CXCR3⁺ CD4⁺ T cells via the CXCL10/CXCR3 axis. Collectively, data reported here support miR-135a affecting multiple cellular processes in response to chlamydial infection.

The Expression and Clinical Significance of miRNA-135a and Bach1 in Colorectal Cancer

Aim

The objective of this study was to explore the correlation between the expression of miRNA-135a and Bach1 in colorectal cancer tissue and the patient's clinical information.

Methods

Sixty patients with colorectal carcinoma were treated as a control group. Real-time quantitative polymerase chain reaction assays and immunohistochemistry methods were performed to detect the expression of miRNA-135a and Bach1 in 60 colorectal carcinomas and adjacent normal tissues, and the clinical and pathologic classifications were also investigated. SPSS 19.00 software was used. All data are represented as mean ± SD of 3 independent experiments. P < 0.05 was considered statistically significant.

Results

miRNA-135a expression levels increased significantly in colon cancer tissues compared with the nontumor control tissues (P < 0.01). miRNA-135a expression levels were higher in stage III/IV than in stage I/II colon cancer patients. The expression level of Bach1 in colorectal cancer was significantly lower (P < 0.01). Bach1 and miRNA-135a were negatively correlated.

Conclusions

The levels of miRNA-135a and Bach1 were opposite: the overexpression of miRNA-135a might downregulate the expression of Bach1, which might be involved in the pathogenesis of colorectal cancer.

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.

miR-5188 augments glioma growth, migration and invasion through an SP1-modulated FOXO1-PI3K/AKT-c-JUN-positive feedback circuit

The biological effect and molecular mechanism of miR-5188 have not been thoroughly investigated. The study aims at elucidating the role of miR-5188 in glioma progression. Human glioma cell lines and tissues were used for functional and expression analysis. Cellular and molecular techniques were performed to explore the functions and mechanisms of miR-5188 in glioma. In our investigation, we demonstrated that miR-5188 promoted cell proliferation, the G1/S transition of the cell cycle, migration and invasion in glioma and reduced the lifespan of glioma-bearing mice. miR-5188 directly targeted FOXO1 and activated PI3K/AKT-c-JUN signalling, which enhanced miR-5188 expression. Moreover, the c-JUN transcription factor functionally bound to the miR-5188 promoter region, forming the positive feedback loop. The feedback loop promoted glioma progression through activating the PI3K/AKT signalling, and this loop is augmented by the interaction between SP1 and c-JUN. Moreover, it was also found that the miR-5188/FOXO1 axis is facilitated by SP1-activated PI3K/AKT/c-JUN signalling. In glioma samples, miR-5188 expression was found to be an unfavourable factor and was positively associated with the mRNA levels of SP1 and c-JUN, whereas negatively associated with the mRNA levels of FOXO1. Our investigation demonstrates that miR-5188 could function as a tumour promoter by directly targeting FOXO1 and participating in SP1-mediated promotion of cell growth and tumorigenesis in glioma.

miR-135a Alleviates Silica-Induced Pulmonary Fibrosis by Targeting NF-κB/Inflammatory Signaling Pathway

Silica exposure triggers inflammatory response and pulmonary fibrosis that is a severe occupational or environmental lung disease with no effective therapies. The complicated biological and molecular mechanisms underlying silica-induced lung damages have not yet been fully understood. miR-135a inhibits inflammation, apoptosis, and cancer cell proliferation. But the roles of miRNA135a involved in the silica-induced lung damages remain largely unexplored. We investigated the roles and mechanisms of miR-135a underlying silica-induced pulmonary fibrosis. The present study showed silica exposure caused the decrease in miR-135a level but the increase in inflammatory mediators. Transduction of lentivirus expressing miR-135a reduced the level of inflammatory mediators in lung tissues from silica-treated mice and improved pulmonary fibrosis which was consistent with the downregulated α-SMA but enhanced E-cadherin. Moreover, miR-135a overexpression inhibited p-p65 level in lung tissues. Overexpression of miR-135a inhibitor strengthened TLR4 protein level and NF-κB activation in BEAS-2B cells. Injection of PDTC, an inhibitor of NF-κB, further reinforced miR-135a-mediated amelioration of inflammation and pulmonary fibrosis induced by silica. The collective data indicate miR-135a restrains NF-κB activation probably through targeting TLR4 to alleviate silica-induced inflammatory response and pulmonary fibrosis.

MiR-1/GOLPH3/Foxo1 Signaling Pathway Regulates Proliferation of Bladder Cancer

Objective:

To investigate role of microRNA-1/Golgi phosphoprotein 3/Foxo1 axis in bladder cancer.

Methods:

The expression of Golgi phosphoprotein 3 was determined in both bladder cancer tissues and cell lines using quantitative real-time polymerase chain reaction and Western blotting, respectively. Golgi phosphoprotein 3 was knocked down by small hairpin RNA. MicroRNA-1 was overexpressed or inhibited by microRNA-1 mimic or inhibitor. Cell viability and proliferation were determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) and colony-formation assay. Cell apoptosis and cycle was detected using flow cytometer. The expression of microRNA-1 and Golgi phosphoprotein 3 was determined using quantitative real-time polymerase chain reaction and Western blotting was used to test the expression of Golgi phosphoprotein 3, Foxo1, p-Foxo1, AKT, p-AKT, p27, and CyclinD1. Binding between microRNA-1 and Golgi phosphoprotein 3 was confirmed by Dual-Luciferase Reporter Assay.

Results:

MicroRNA-1 was downregulated in bladder cancer tissues, while Golgi phosphoprotein 3 was overexpressed in bladder cancer cells and tissues. In both bladder cancer 5637 and T24 cell lines, the cell viability and proliferation were dramatically reduced when Golgi phosphoprotein 3 was knocked down. The inhibition of Golgi phosphoprotein 3 remarkably promoted cell apoptosis and induced cell-cycle arrest, as well as decreased the expression of p-Foxo1, p-AKT, and CyclinD1 and increased the expression of p27. The overexpression of microRNA-1 significantly inhibited cell viability and proliferation, induced G-S cell-cycle arrest, and decreased the expression of Golgi phosphoprotein 3, p-Foxo1, and CyclinD1 and upregulated p27, while inhibition of microRNA-1 led to opposite results. Golgi phosphoprotein 3 was a direct target for microRNA-1.

Conclusion:

Overexpression of microRNA-1 inhibited cell proliferation and induced cell-cycle arrest of bladder cancer cells through targeting Golgi phosphoprotein 3 and regulation of Foxo1.

MiR-135a biogenesis and regulation in malignancy: a new hope for cancer research and therapy

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs that affect posttranscriptional regulation by binding to the 3′-untranslated region of target messenger RNAs. MiR-135a is a critical miRNA that regulates gene expression, and many studies have focused on its function in cancer research. MiR-135a is dysregulated in various cancers and regulates cancer cell proliferation and invasion via several signaling pathways, such as the MAPK and JAK2/STAT3 pathways. MiR-135a has also been found to promote or inhibit the epithelial-mesenchymal transition and chemoresistance in different cancers. Several studies have discovered the value of miR-135a as a novel biomarker for cancer diagnosis and prognosis. These studies have suggested the potential of therapeutically manipulating miR-135a to improve the outcome of cancer patients. Although these findings have demonstrated the role of miR-135a in cancer progression and clinical applications, a number of questions remain to be answered, such as the dual functional roles of miR-135a in cancer. In this review, we summarize the available studies regarding miR-135a and cancer, including background on the biogenesis and expression of miR-135a in cancer and relevant signaling pathways involved in miR-135a-mediated tumor progression. We also focus on the clinical application of miR-135a as a biomarker in diagnosis and as a therapeutic agent or target in cancer treatment, which will provide a greater level of insight into the translational value of miR-135a.

Serum microRNA-135a as a diagnostic biomarker in non-small cell lung cancer

The purpose of our research was to evaluate diagnostic performance of serum microRNA-135a (miR-135a) in non-small cell lung cancer (NSCLC).Quantitative real time-polymerase chain reaction was employed to detect the expression serum of miR-135a in NSCLC patients and controls. The influence of serum miR-135a level on clinical characteristics of NSCLC patients was explored through the Chi-square test. Serum carcinoembryonic antigen (CEA) level was estimated via enzyme-linked immunosorbent assay. Receiver operating characteristic (ROC) curve was plotted to elucidate diagnostic roles of serum miR-135a and CEA in NSCLC.The expression level of serum miR-135a was significantly lower in NSCLC patients than in healthy controls (0.40 ± 0.29 vs 1.00 ± 0.40, P < .001). Moreover, miR-135a expression was related to lymph node metastasis (P = .021), tumor differentiation (P = .020), and tumor node metastasis stage (P = .031). ROC curve showed serum miR-135a level could discriminate NSCLC patients from healthy controls (P < .0001) with a corresponding cutoff value of 0.665, and a sensitivity and specificity of 81.3% and 83.1%, respectively. The area under the curve was 0.888. In diagnosis analysis on the combination of miR-135a and CEA, when its specificity was maintained at 90%, diagnosis cut-off point reached 0.678.Serum miR-135a level is significantly downregulated in NSCLC and serves as a potential diagnostic biomarker for the disease.

LncRNA MBNL1-AS1 represses cell proliferation and enhances cell apoptosis via targeting miR-135a-5p/PHLPP2/FOXO1 axis in bladder cancer

LncRNAs have been shown to play essential roles in bladder cancer (BC) progress. Our microarrays of clinical samples firstly screened that lncRNA muscleblind‐like 1 antisense RNA 1 (MBNL1‐AS1) was poorly expressed in BC tissues. However, its biological function in BC remains not well understood. Here we examined the clinical correlations with MBNL1‐AS1 in BC patients. Then, 5673 and T24 cell lines were employed to investigate the role of MBNL1‐AS1 in the proliferation and apoptosis of BC cells in vitro and in vivo. Furthermore, miR‐135a‐5p (miR‐135a)/PHLPP2/FOXO1 axis was focused to explore its regulatory mechanism in BC. The results showed that MBNL1‐AS1 was significantly downregulated in bladder tumor tissues, and associated with BC progression. In vitro, MBNL1‐AS1 knockdown increased the number of viable cells and bromodeoxyuridine‐positive cells, accelerated cell cycle, and dysregulated proliferative regulators (Ki67, p21, p27, and Cyclin D1) in BC cells. The apoptotic cells and the cleavages of caspase‐3/9 were reduced in MBNL1‐AS1‐silenced BC cells. Overexpression of MBNL1‐AS1 had opposite effects on BC cell proliferation and apoptosis. Moreover miR‐135a was demonstrated to interact with MBNL1‐AS1, and inhibiting miR‐135a reversed the effects of shMBNL1‐AS1 on BC cells. The downstream effectors (PHLPP2 and FOXO1) were positively regulated by MBNL1‐AS1, but negatively regulated by miR‐135a. Similar results were also observed in xenograft tumors. In conclusion, this study firstly suggests that MBNL1‐AS1 acts as a tumor suppressor of BC by targeting miR‐135a/PHLPP2/FOXO1 axis, providing a novel insight for BC diagnosis and treatment.

Long non-coding RNA GAS5 promotes osteogenic differentiation of bone marrow mesenchymal stem cells by regulating the miR-135a-5p/FOXO1 pathway

Studies have shown that promoting the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts could protect against osteoporosis. Increasing evidence demonstrates that long non-coding RNAs (lncRNAs) participate in BMSC osteogenic differentiation. This study aimed to investigate the role and underlying mechanism of growth arrest-specific transcript 5 (GAS5) in osteogenic differentiation. The mechanism was mainly focused on miR-135a-5p/FOXO1 pathway by gain- and loss-of function tests. GAS5 and FOXO1 expression was decreased, whereas miR-135a-5p expression was increased, in the BMSCs from osteoporotic mice. Levels of GAS5 and FOXO1 were increased and miR-135a-5p expression was decreased during osteogenic differentiation of BMSCs. Overexpression of GAS5 promoted, whereas knockdown of GAS5 suppressed, BMSC osteogenic differentiation. As for the mechanism, GAS5 functioned as a competing endogenous RNA for miR-135a-5p to regulate FOXO1 expression. In conclusion, GAS5 promoted osteogenesis of BMSCs by regulating the miR-135a-5p/FOXO1 axis. This finding suggests that targeting GAS5 may be a useful therapy for treating postmenopausal osteoporosis.

Comprehensive circular RNA profiling reveals the regulatory role of the hsa_circ_0137606/miR‑1231 pathway in bladder cancer progression

Bladder cancer (BC) is one of the most common malignant tumors in males globally. Its progression imposes a heavy burden on patients; however, the expression profile of circular (circ)RNAs in BC progression remains unclear. This study explored changes in circRNA expression during BC progression by sequencing different grade BC samples and normal controls to reveal the circRNA expression profiles of different BC grades. Gene Ontology (GO) and Kyoto Encyclopedia of Gens and Genomes (KEGG) pathway analyses, and protein-protein interaction network construction were used to predict pathways that the differentially expressed circRNAs may participate in. circRNA expression levels were detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and dual-luciferase reporter assays were used to investigate the interactions between circRNA and microRNA (miR). Cell Counting Kit-8 and Transwell assays were also performed to detect cell proliferation, migration, and invasion. In total, 244 circRNAs were found to be differentially expressed in high-grade BC compared to low-grade BC, whilst 316 dysregulated circRNAs were detected in high-grade BC compared with normal urothelium. Furthermore, 42 circRNAs overlapped between the two groups, seven of which were randomly selected and detected by RT-qPCR to validate the sequencing results. GO analysis and KEGG pathway analyses revealed that the differentially expressed circRNAs may participate in BC via 'GTPase activity regulation', 'cell junction', and 'focal adhesion' pathways. Of note, we proposed that a novel circRNA in BC progression, hsa_circ_0137606, could suppress BC proliferation and metastasis by sponging miR-1231. Through bioinformatics analysis, we predicted that PH domain and leucine rich repeat protein phosphatase 2 could be a target of the hsa_circ_0137606/miR-1231 axis in BC progression. Using high-throughput sequencing, this study revealed the circRNA expression profiles of different grades of BC and proposed that the novel circRNA, hsa_circ_0137606, suppresses BC proliferation and metastasis by sponging miR-1231. Our findings may provide novel insight into potential therapeutic targets for treating BC.

MiR-135a-5p Is Critical for Exercise-Induced Adult Neurogenesis

Physical exercise stimulates adult hippocampal neurogenesis and is considered a relevant strategy for preventing age-related cognitive decline in humans. The underlying mechanisms remains controversial. Here, we show that exercise increases proliferation of neural precursor cells (NPCs) of the mouse dentate gyrus (DG) via downregulation of microRNA 135a-5p (miR-135a). MiR-135a inhibition stimulates NPC proliferation leading to increased neurogenesis, but not astrogliogenesis, in DG of resting mice, and intriguingly it re-activates NPC proliferation in aged mice. We identify 17 proteins (11 putative targets) modulated by miR-135 in NPCs. Of note, inositol 1,4,5-trisphosphate (IP3) receptor 1 and inositol polyphosphate-4-phosphatase type I are among the modulated proteins, suggesting that IP3 signaling may act downstream miR-135. miR-135 is the first noncoding RNA essential modulator of the brain's response to physical exercise. Prospectively, the miR-135-IP3 axis might represent a novel target of therapeutic intervention to prevent pathological brain aging.

A urinary microRNA (miR) signature for diagnosis of bladder cancer

INTRODUCTION

Bladder cancer (BC) is diagnosed by cystoscopy, which is invasive, costly and causes considerable patient discomfort. MicroRNAs (miR) are dysregulated in BC and may serve as non-invasive urine markers for primary diagnostics and monitoring. The purpose of this study was to identify a urinary miR signature that predicts the presence of BC.

METHODS

For the detection of potential urinary miR markers, expression of 384 different miRs was analyzed in 16 urine samples from BC patients and controls using a Taqman™ Human MicroRNA Array (training set). The identified candidate gene signature was subsequently validated in an independent cohort of 202 urine samples of patients with BC and controls with microscopic hematuria. The final miR signature was developed from a multivariable logistic regression model.

RESULTS

Analysis of the training set identified 14 candidate miRs for further analysis within the validation set. Using backward stepwise elimination, we identified a subset of 6 miRs (let-7c, miR-135a, miR-135b, miR-148a, miR-204, miR-345) that distinguished BC from controls with an area under the curve of 88.3%. The signature was most accurate in diagnosing high-grade non-muscle invasive BC (area under the curve = 92.9%), but was capable to identify both low-grade and high-grade disease as well as non-muscle and muscle-invasive BC with high accuracies.

CONCLUSIONS

We identified a 6-gene miR signature that can accurately predict the presence of BC from urine samples, independent of stage and grade. This signature represents a simple urine assay that may help reducing costs and morbidity associated with invasive diagnostics.

MicroRNA-135a-3p is downregulated and serves as a tumour suppressor in ovarian cancer by targeting CCR2

MicroRNAs have been demonstrated to play a crucial role in the development of ovarian cancer. Many studies prove that forms of miR-135a, including miR-135a-5p and miR-135a-3p, serve as tumour suppressors in multiple cancers. Nevertheless, the precise function of miR-135a-3p and the molecular mechanisms underlying the involvement of miR-135a-3p in ovarian carcinoma cell growth and metastasis remain largely unknown. Herein, we report that miR-135a-3p expression was significantly downregulated in ovarian carcinoma tissues compared with corresponding adjacent non-tumour tissues. Ectopic miR-135a-3p expression inhibited ovarian carcinoma cell proliferation, migration and invasion in vitro. Additionally, the overexpression of miR-135a-3p inhibited epithelial-mesenchymal transition (EMT) in ovarian cancer cells. A luciferase reporter assay confirmed that the C-C chemokine receptor type 2 (CCR2) gene was the target of miR-135a-3p. In addition, CCR2 depletion mimicked the inhibitory effects of miR-135a-3p on ovarian cancer cells in vitro. Rescue experiments using CCR2 overexpression further verified that CCR2 was a functional target of miR-135a-3p. Xenograft model assays demonstrated that miR-135a-3p functions as an anti-oncogene by targeting CCR2 in vivo. Taken together, these data prove that miR-135a-3p serves as a tumour suppressor gene in ovarian cancer by regulating CCR2.

Functional role of microRNA-135a in colitis

Background

Inflammatory bowel disease (IBD) is one of the chronic gastrointestinal diseases with increasing risk of colon cancer development in the future. Apoptosis and inflammation play an important role in the etiology of this disease. MicroRNAs are associated with etiology of different diseases including IBD. In this study, we aimed to explore the role of miR-135a in the etiology of colitis in murine model of DSS-induced colitis.

Results

The results showed that expression of miR-135a in colonic cells was suppressed and up-regulating miR-135a inhibited apoptosis and inflammation of colonic epithelial cells. Additionally, Hif1α was identified as the target gene of miR-135a which promoted apoptosis and inflammation as knockdown of Hif1α led to the suppression of both apoptosis and inflammation.

Conclusions

Overexpression of miR-135a might be beneficial in IBD due to its anti-apoptosis and anti-inflammation effects in vitro.

Elevated microRNA-135a is associated with pulmonary arterial hypertension in experimental mouse model

Multiple causes are associated with the complex mechanism of pathogenesis of pulmonary arterial hypertension (PAH), but the molecular pathway in the pathogenesis of PAH is still insufficiently understood. In this study, we investigated epigenetic changes that cause PAH induced by exposure to combined Th2 antigen (Ovalbumin, OVA) and urban particulate matter (PM) in mice. To address that, we focused on the epigenetic mechanism, linked to microRNA (miR)-135a. We found that miR-135a levels were significantly increased, and levels of bone morphogenetic protein receptor type II (BMPR2) which is the target of miR-135a, were significantly decreased in this experimental PAH mouse model. Therefore to evaluate the role of miR-135a, we injected AntagomiR-135a into this mouse model. AntagomiR-135a injected mice showed decreased right ventricular systolic pressures (RVSPs), right ventricular hypertrophy (RVH), and the percentage of severely thickened pulmonary arteries compared to control scrambled miRNA injected mice. Both mRNA and protein expression of BMPR2 were recovered in the AntagomiR-135a injected mice compared to control mice. Our study understands if miR-135a could serve as a biomarker helping to manage PAH. The blocking of miR-135a could lead to new therapeutic modalities to alleviate exacerbation of PAH caused by exposure to Th2 antigen and urban air pollution.

miR-135a promotes gastric cancer progression and resistance to oxaliplatin

Resistance to oxaliplatin (OXA)-based chemotherapy regimens continues to be a major cause of gastric cancer (GC) recurrence and metastasis. We analyzed GC samples and matched non-tumorous control stomach tissues from 280 patients and found that miR-135a was overexpressed in GC samples relative to control tissues. Tumors with high miR-135a expression were more likely to have aggressive characteristics (high levels of carcino-embryonic antigen, vascular invasion, lymphatic metastasis, and poor differentiation) than those with low levels. Patients with greater tumoral expression of miR-135a had shorter overall survival times and times to disease recurrence. Furthermore, miR-135a, which promotes the proliferation and invasion of OXA-resistant GC cells, inhibited E2F transcription factor 1 (E2F1)-induced apoptosis by downregulating E2F1 and Death-associated protein kinase 2 (DAPK2) expression. Our results indicate that higher levels of miR-135a in GC are associated with shorter survival times and reduced times to disease recurrence. The mechanism whereby miR-135a promotes GC pathogenesis appears to be the suppression of E2F1 expression and Sp1/DAPK2 pathway signaling.

Targeting IGF1R pathway in cancer with microRNAs: How close are we?

Cancer of the head and neck are the most common cancers in India and account for 30% of all cancers. At molecular level, it could be attributed to the overexpression of growth factors like IGF1-R, EGFR, VEGF-R and deregulation of cell cycle regulators and tumor suppressors. IGF1-R is an emerging target in head and neck cancer treatment, because of its reported role in tumor development, progression and metastasis. IGF1R targeted agents are in advanced stages of clinical development. Nevertheless, these agents suffer from several disadvantages including acquired resistance and toxic side effects. Hence there is a need for developing newer agents targeting not only the receptor but also its downstream signaling. miRNAs are considered as master regulators of gene expression of multiple genes and has been widely reported to be a promising therapeutic strategy. This review discusses the present status of research in both these arenas and emphasizes the role of miRNA as a promising agent for biologic therapy.

Effects of microRNA-135a on the epithelial-mesenchymal transition, migration and invasion of bladder cancer cells by targeting GSK3β through the Wnt/β-catenin signaling pathway

This study investigated the effects of microRNA-135a (miR-135a) targeting of glycogen synthase kinase 3β (GSK3β) on the epithelial–mesenchymal transition (EMT), migration and invasion of bladder cancer (BC) cells by mediating the Wnt/β-catenin signaling pathway. BC and adjacent normal tissues were collected from 165 BC patients. Western blotting and quantitative real-time PCR were used to detect the expression of GSK3β, β-catenin, cyclinD1, E-cadherin, vimentin and miR-135a in BC tissues and cells. Cells were assigned to blank, negative control (NC), miR-135a mimics, miR-135a inhibitors, small interfering RNA (siRNA)-GSK3β or miR-135a inhibitors+siRNA-GSK3β groups. miR-135a, β-catenin, cyclinD1 and vimentin expression increased, while GSK3β and E-cadherin expression decreased in BC tissues compared with adjacent normal tissues. Compared with the blank and NC groups, the expression of miR-135a, β-catenin, cyclinD1 and vimentin was higher, and cell proliferation, migration, invasion and tumor growth were increased in the miR-135a mimics and siRNA-GSK3β groups. These groups showed an opposite trend in GSK3β and E-cadherin expression and cell apoptosis. The miR-135a inhibitors group was inversely correlated with the blank and NC groups. It was concluded that miR-135a accelerates the EMT, invasion and migration of BC cells by activating the Wnt/β-catenin signaling pathway through the downregulation of GSK3β expression.

MiR-135a Promotes Inflammatory Responses of Vascular Smooth Muscle Cells From db/db Mice via Downregulation of FOXO1

It has been shown that microRNAs (miRNAs) greatly affect the functions of vascular smooth muscle cells (VSMC), but the effects of mRNAs under diabetic conditions remain unclear.Using a model of diabetic db/db mice, we studied the functions of microRNA-135a (miR-135a) during VSMC dysfunction.Compared to control WT mice, miR-135a expression in VSMC was significantly increased while the level of forkhead box O1 (FOXO1) protein decreased significantly. After transfecting miR-135a mimics into VSMC, the expression of FOXO1 was decreased, while cyclooxygenase-2 (COX-2) and monocyte chemoattractant protein-1 (MCP-1) expression levels were increased, thus promoting the interaction between monocytes and WT VSMC. On the other hand, transfection of an miR-135a inhibitor reversed the activated interaction between monocytes and db/db VSMC. The pro-inflammatory responses could also be enhanced by using siRNAs to silence the FOXO1 gene in WT VSMC, suggesting a negative regulatory role of FOXO1. FOXO1 siRNAs and miR-135a mimics could both enhance the transcriptional activity of COX-2 promoter. Using chromatin immunoprecipitation, we found that in db/db VSMC, the occupancy in promoter regions of inflammatory genes by FOXO1 was reduced.miR-135a increased the inflammatory responses of VSMC involved in complications of vascular diseases by downregulating the expression of FOXO1.

Tumor-suppressive miRNA-135a inhibits breast cancer cell proliferation by targeting ELK1 and ELK3 oncogenes

Breast cancer is the most common malignant disease amongst women. miRNAs are small, non-coding RNAs that regulate gene expression, thus have the potential to play an important role during cancer development. Emerging evidence shows that miR-135a is down-regulated in breast cancer cells, but the functional roles of miR-135a in breast cancer cells remains unexplored. For this purpose, we investigated the expression of miR-135a in breast cancer cells and explored its functional role during breast cancer progression. In vitro study showed that miR-135a may be a novel tumor suppressor. Further studies showed that transcription factors ELK1 and ELK3 are direct target genes of miR-135a that modulates the suppressive function of miR-135a in breast cancer cells. Induced expression of miR-135a significantly downregulated the expression of ELK1 and ELK3 both at mRNA and protein levels. Furthermore, the effect of miR-135a in MCF-7 and T47D cells was investigated by the overexpression of miR-135a mimics. In vitro, induced expression of miR-135a in breast cancer cells inhibited cell Proliferation and clongenicity. Moreover, a luciferase activity assay revealed that miR-135a could directly target the 3'-untranslated region (3' UTRS) of ELK1 and ELK3 oncogenes. In addition, rescue experiment demonstrated that the promoted cell growth by transcription factors ELK1 and ELK3 was attenuated by the over-expression of miR-135a. Our study demonstrates that miR-135a regulates cell proliferation in breast cancer by targeting ELK1 and ELK3 oncogenes, and suggests that miR-135a potentially can act as a tumor suppressor.

Understanding the Role of Non-Coding RNAs in Bladder Cancer: From Dark Matter to Valuable Therapeutic Targets

The mortality and morbidity that characterize bladder cancer compel this malignancy into the category of hot topics in terms of biomolecular research. Therefore, a better knowledge of the specific molecular mechanisms that underlie the development and progression of bladder cancer is demanded. Tumor heterogeneity among patients with similar diagnosis, as well as intratumor heterogeneity, generates difficulties in terms of targeted therapy. Furthermore, late diagnosis represents an ongoing issue, significantly reducing the response to therapy and, inevitably, the overall survival. The role of non-coding RNAs in bladder cancer emerged in the last decade, revealing that microRNAs (miRNAs) may act as tumor suppressor genes, respectively oncogenes, but also as biomarkers for early diagnosis. Regarding other types of non-coding RNAs, especially long non-coding RNAs (lncRNAs) which are extensively reviewed in this article, their exact roles in tumorigenesis are—for the time being—not as evident as in the case of miRNAs, but, still, clearly suggested. Therefore, this review covers the non-coding RNA expression profile of bladder cancer patients and their validated target genes in bladder cancer cell lines, with repercussions on processes such as proliferation, invasiveness, apoptosis, cell cycle arrest, and other molecular pathways which are specific for the malignant transformation of cells.

Posttranscriptional regulation of FOXO expression: microRNAs and beyond

Forkhead box, class O (FOXO) transcription factors are major regulators of diverse cellular processes, including fuel metabolism, oxidative stress response and redox signalling, cell cycle progression and apoptosis. Their activities are controlled by multiple posttranslational modifications and nuclear-cytoplasmic shuttling. Recently, post-transcriptional regulation of FOXO synthesis has emerged as a new regulatory level of their functions. Accumulating evidence suggests that this post-transcriptional mode of regulation of FOXO activity operates in response to stressful stimuli, including oxidative stress. Here, we give a brief overview on post-transcriptional regulation of FOXO synthesis by microRNAs (miRNAs) and by RNA-binding regulatory proteins, human antigen R (HuR) and quaking (QKI). Aberrant post-transcriptional regulation of FOXOs is frequently connected with various disease states. We therefore discuss characteristic examples of FOXO regulation at the post-transcriptional level under various physiological and pathophysiological conditions, including oxidative stress and cancer. The picture emerging from this summary points to a diversity of interactions between miRNAs/miRNA-induced silencing complexes and RNA-binding regulatory proteins. Better insight into these complexities of post-transcriptional regulatory interactions will add to our understanding of the mechanisms of pathological processes and the role of FOXO proteins.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

Role of STAT3 and FOXO1 in the Divergent Therapeutic Responses of Non-metastatic and Metastatic Bladder Cancer Cells to miR-145

Although miR-145 is the most frequently downregulated miRNA in bladder cancer, its exact stage association and downstream effector have not been defined. Here, we found that miR-145 was upregulated in human patients with bladder cancer with lymph node metastasis and in metastatic T24T cell line. Forced expression of miR-145 promoted anchorage-independent growth of T24T cells accompanied by the downregulation of forkhead box class O1 (FOXO1). In contrast, in non-metastatic T24 cells, miR-145 overexpression inhibited cell growth with upregulation of FOXO1, and the knockdown of FOXO1 abolished the miR-145-mediated inhibition of cell growth. Mechanistic studies revealed that miR-145 directly bound to and attenuated 3'-untranslated region (UTR) activity of foxo1 mRNA in both T24 and T24T cells. Interestingly, miR-145 suppressed STAT3 phosphorylation at Tyr705 and increased foxo1 promoter transcriptional activity in T24 cells, but not in T24T cells, suggesting a role of STAT3 in the divergent responses to miR-145. Supporting this was our finding that STAT3 knockdown mimicked miR-145-mediated upregulation of FOXO1 in T24T cells and inhibition of anchorage-independent growth. Consistently, ectopic expression of miR-145 promoted tumor formation of xenograft T24T cells, whereas such promoting effect became inhibitory due to specific knockdown of STAT3. Together, our findings demonstrate the stage-specific association and function of miR-145 in bladder cancers and provide novel insights into the therapeutic targeting of miR-145. Mol Cancer Ther; 16(5); 924-35. ©2017 AACR.

FOXO1 down-regulation is associated with worse outcome in bladder cancer and adds significant prognostic information to p53 overexpression

Nuclear FOXOs mediate cell cycle arrest and promote apoptosis. FOXOs and p53 could have similar effects as tumor suppressor genes. In spite of extensive literature, little is known about the role of FOXO1 and its relationship with p53 status in bladder cancer. Expression of FOXO1 and p53 were analyzed by immunohistochemistry in 162 urothelial carcinomas (UC). Decreased FOXO1 expression, p53 overexpression and the combination FOXO1 down-regulation/p53 overexpression were strongly associated with high grade (P=.030; P=.017; P=.004, respectively), high stage (P=.0001; P<.0001; P<.0001, respectively) or both (P=.0004; P<.0001; P<.0001, respectively). In the overall series of cases, p53 overexpression was associated with tumor progression (hazard ratio [HR]=3.18, 95% confidence interval [CI] 1.19-8.48, P=.02), but this association was even stronger if having any alteration in any of the 2 genes was considered (HR=3.51, 95% CI 1.34-9.21, P=.01). Having both FOXO1 down-regulation and p53 overexpression was associated with disease recurrence (HR=2.75, 95% CI 1.06-7.13, P=.03). In the analysis of the different subgroups, having any alteration in any of the 2 genes was associated with progression in low-grade (P=.005) and pTa (P=.006) tumors. Finally, the combined FOXO1 down-regulation/p53 overexpression was associated with disease recurrence specifically in high-grade (P=.04) and in pT1 stage tumors (P=.007). Adding FOXO1 expression to the immunohistochemical analysis of p53 can provide relevant prognostic information on progression and recurrence of bladder cancer. It may be particularly informative on the risk of progression in the more indolent and on the risk of recurrence in the more aggressive tumors.

miR-3117 regulates hepatocellular carcinoma cell proliferation by targeting PHLPPL

Altered microRNA expression is associated with tumor proliferation, metastasis, and tumorigenesis. In this study, we studied the role of miR-3117 in hepatocellular carcinoma (HCC) cell proliferation and found that miR-3117 was upregulated in HCC tissues and cells. MTT assay, soft agar growth assay, BrdU assay, and cell cycle assay revealed that miR-3117 overexpression promoted HCC HepG2 cell proliferation and that knockdown of miR-3117 suppressed HepG2 proliferation. Mechanism analysis suggested PH domain and leucine-rich repeat protein phosphatase-like (PHLPPL) as the target of miR-3117. Luciferase reporter assay suggested that miR-3117 directly binds to the 3'UTR of PHLPPL. Double knockdown of miR-3117 and PHLPPL copied the phenotypes caused by miR-3117 overexpression, suggesting that miR-3117 contributes to the proliferation of HepG2 by targeting PHLPPL. Our study provided a target for HCC therapy.

The oncoprotein HBXIP suppresses gluconeogenesis through modulating PCK1 to enhance the growth of hepatoma cells

Hepatitis B X-interacting protein (HBXIP) as an oncoprotein plays crucial roles in the development of cancer, involving glucose metabolism reprogramming. In this study, we are interested in whether the oncoprotein HBXIP is involved in the modulation of gluconeogenesis in liver cancer. Here, we showed that the expression level of phosphoenolpyruvate carboxykinase (PCK1), a key enzyme of gluconeogenesis, was lower in clinical hepatocellular carcinoma (HCC) tissues than that in normal tissues. Mechanistically, HBXIP inhibited the expression of PCK1 through down-regulating transcription factor FOXO1 in hepatoma cells, and up-regulated miR-135a targeting the 3'UTR of FOXO1 mRNA in the cells. In addition, HBXIP increased the phosphorylation levels of FOXO1 protein by activating PI3K/Akt pathway, leading to the export of FOXO1 from nucleus to cytoplasm. Strikingly, over-expression of PCK1 could abolish the HBXIP-promoted growth of hepatoma cells in vitro and in vivo. Thus, we conclude that the oncoprotein HBXIP is able to depress the gluconeogenesis through suppressing PCK1 to promote hepatocarcinogenesis, involving miR-135a/FOXO1 axis and PI3K/Akt/p-FOXO1 pathway. Our finding provides new insights into the mechanism by which oncoprotein HBXIP modulates glucose metabolism reprogramming in HCC.

Androgen-induced miR-135a acts as a tumor suppressor through downregulating RBAK and MMP11, and mediates resistance to androgen deprivation therapy

The main challenge in the treatment of prostate cancer (PCa) is that the majority of patients inevitably develop resistance to androgen deprivation. However, the mechanisms involved in hormone independent behavior of PCa remain unclear. In the present study, we identified androgen-induced miR-135a as a direct target of AR. Functional studies revealed that overexpression of miR-135a could significantly decrease cell proliferation and migration, and induce cell cycle arrest and apoptosis in PCa. We identified RBAK and MMP11 as direct targets of miR-135a in PCa by integrating bioinformatics analysis and experimental assays. Mechanistically, miR-135a repressed PCa migration through downregulating MMP11 and induced PCa cell cycle arrest and apoptosis by suppressing RBAK. Consistently, inverse correlations were also observed between the expression of miR-135a and RBAK or MMP11 in PCa samples. In addition, low miR-135a and high RBAK and MMP11 expression were positively correlated with PCa progression. Also, PI3K/AKT pathway was confirmed to be an upstream regulation signaling of miR-135a in androgen-independent cell lines. Accordingly, we reported a resistance mechanism to androgen deprivation therapy (ADT) mediated by miR-135a which might be downregulated by androgen depletion and/or PI3K/AKT hyperactivation, in castration-resistant prostate cancer (CRPC), thus promoting tumor progression. Taken together, miR-135a may represent a new diagnostic and therapeutic biomarker for castration-resistant PCa.

miR-135a acts as a tumor suppressor in gastric cancer in part by targeting KIFC1

miR-135a was downregulated in the majority of human primary gastric cancer (GC) tissues and GC cell lines. Kinesin family member C1 (KIFC1) was significantly upregulated in GC tissues and cell lines and promoted GC development and progression. We searched for miR-135a targets by using MiRanda, TargetScan, and PicTar tools, and found that KIFC1 was a potential target of miR-135a. Based on these findings, we speculated that miR-135a might target KIFC1 to inhibit GC growth. We determined the expression of miR-135a and KIFC1 by quantitative real-time polymerase chain reaction and Western blot assays, respectively, and found downregulation of miR-135a and upregulation of KIFC1 in GC tissues and cell lines. Cell proliferation and apoptosis assays showed that knockdown of KIFC1 inhibited proliferation and promoted apoptosis of GC cells, and miR-135a mimics had similar effects on GC cell proliferation and apoptosis. Furthermore, we verified that KIFC1 was a direct target of miR-135a, which confirmed our speculation that the functional effect of miR-135a on GC cells, at least, in part, depends on KIFC1. These findings suggest that miR-135a has an important role in the suppression of GC and presents a novel mechanism of miRNA-mediated KIFC1 expression in cancer cells.

The role of microRNAs in bladder cancer

Bladder cancer (BC) is the fifth most common cancer worldwide and is associated with significant morbidity and mortality. The prognosis of muscle invasive BC is poor, and recurrence is common after radical surgery or chemotherapy. Therefore, new diagnostic methods and treatment modalities are critical. MicroRNAs (miRNAs), a class of small noncoding RNAs, regulate the expression of protein-coding genes by repressing translation or cleaving RNA transcripts in a sequence-specific manner. miRNAs have important roles in the regulation of genes involved in cancer development, progression, and metastasis. The availability of genomewide miRNA expression profiles by deep sequencing technology has facilitated rapid and precise identification of aberrant miRNA expression in BC. Indeed, several miRNAs that are either upregulated or downregulated have been shown to have associations with significant cancer pathways. Furthermore, many miRNAs, including those that can be detected in urine and blood, have been studied as potential noninvasive tumor markers for diagnostic and prognostic purposes. Here, we searched PubMed for publications describing the role of miRNAs in BC by using the keywords "bladder cancer" and "microRNA" on March 1, 2016. We found 374 papers and selected articles written in English in which the level of scientific detail and reporting were sufficient and in which novel findings were demonstrated. In this review, we summarize these studies from the point of view of miRNA-related molecular networks (specific miRNAs and their targets) and miRNAs as tumor markers in BC. We also discuss future directions of miRNA studies in the context of therapeutic modalities.

Hydroxytyrosol supplementation modulates the expression of miRNAs in rodents and in humans

Dietary microRNAs (miRNAs) modulation could be important for health and wellbeing. Part of the healthful activities of polyphenols might be due to a modulation of miRNAs' expression. Among the most biologically active polyphenols, hydroxytyrosol (HT) has never been studied for its actions on miRNAs. We investigated whether HT could modulate the expression of miRNAs in vivo. We performed an unbiased intestinal miRNA screening in mice supplemented (for 8 weeks) with nutritionally relevant amounts of HT. HT modulated the expression of several miRNAs. Analysis of other tissues revealed consistent HT-induced modulation of only few miRNAs. Also, HT administration increased triglycerides levels. Acute treatment with HT and in vitro experiments provided mechanistic insights. The HT-induced expression of one miRNA was confirmed in healthy volunteers supplemented with HT in a randomized, double-blind and placebo-controlled trial. HT consumption affects specific miRNAs' expression in rodents and humans. Our findings suggest that the modulation of miRNAs' action through HT consumption might partially explain its healthful activities and might be pharmanutritionally exploited in current therapies targeting endogenous miRNAs. However, the effects of HT on triglycerides warrant further investigations.

Up-regulation of microRNA-135a protects against myocardial ischemia/reperfusion injury by decreasing TXNIP expression in diabetic mice

BACKGROUND AND AIMS

The heart in diabetic state is sensitive to myocardial ischemia reperfusion (mI/R) injury. In the present study, we investigated the potential mechanisms of modulating mI/R injury in diabetic state.

METHODS

Diabetic db/db mice and control non-diabetic mice were administrated with mI/R injury or sham operation. Mouse atrial-derived cardiac cell line HL-1 subjected to hypoxia-reoxygenation (H/R) was used as in vitro model of I/R injury to the heart.

RESULTS

Compared with normal mice, mI/R elevated the levels of myocardial infarct size, apoptosis and TXNIP expression (in mRNA and protein) in diabetic mice. Myocardial miR-135a expression level was reduced in diabetic mice regardless of mI/R treatment or not. MiR-135a overexpression protected myocardial cells from mI/R injury in diabetic mice. In vitro, high glucose incubation contributed to a significant down-regulation of miR-135a and up-regulation of TXNIP in cells with or without H/R treatment. Luciferase reporter assay showed that TXNIP was a target gene of miR-135a. MiR-135a overexpression protected HL-1 cells from H/R injury in high glucose condition, while this effect was reversed by up-regulated TXNIP.

CONCLUSION

miR-135a protects against mI/R injury by decreasing TXNIP expression in diabetic state.

Redox regulation of FoxO transcription factors

Transcription factors of the forkhead box, class O (FoxO) family are important regulators of the cellular stress response and promote the cellular antioxidant defense. On one hand, FoxOs stimulate the transcription of genes coding for antioxidant proteins located in different subcellular compartments, such as in mitochondria (i.e. superoxide dismutase-2, peroxiredoxins 3 and 5) and peroxisomes (catalase), as well as for antioxidant proteins found extracellularly in plasma (e.g., selenoprotein P and ceruloplasmin). On the other hand, reactive oxygen species (ROS) as well as other stressful stimuli that elicit the formation of ROS, may modulate FoxO activity at multiple levels, including posttranslational modifications of FoxOs (such as phosphorylation and acetylation), interaction with coregulators, alterations in FoxO subcellular localization, protein synthesis and stability. Moreover, transcriptional and posttranscriptional control of the expression of genes coding for FoxOs is sensitive to ROS. Here, we review these aspects of FoxO biology focusing on redox regulation of FoxO signaling, and with emphasis on the interplay between ROS and FoxOs under various physiological and pathophysiological conditions. Of particular interest are the dual role played by FoxOs in cancer development and their key role in whole body nutrient homeostasis, modulating metabolic adaptations and/or disturbances in response to low vs. high nutrient intake. Examples discussed here include calorie restriction and starvation as well as adipogenesis, obesity and type 2 diabetes.

MiR-135 post-transcriptionally regulates FOXO1 expression and promotes cell proliferation in human malignant melanoma cells

Malignant melanoma is the deadliest form of all skin cancers. Recently, microRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression by targeted repression of transcription and translation and play essential roles during cancer development. Our study showed that miR-135a is upregulated in malignant melanoma tissues and cell lines by using Real-time PCR assay. Enforced expression of miR-135a in malignant melanoma cells promotes cell proliferation, tumorigenicity, and cell cycle progression, whereas inhibition of miR-135a reverses the function. Additionally, we demonstrated FOXO1 is a direct target of miR-135a and transcriptionally down-regulated by miR-135a. Ectopic expression of miR-135a led to downregulation of the FOXO1 protein, resulting in upregulation of Cyclin D1, and downregulation of P21(Cip1) and P27(Kip1) through AKT pathway. Our findings suggested that miR-135a represents a potential onco-miRNA and plays an important role in malignant melanoma progression by suppressing FOXO1 expression.