miR-29 miRNAs activate p53 by targeting p85 alpha and CDC42

MiR-29b expression is associated with a dexmedetomidine-mediated protective effect against oxygen-glucose deprivation-induced injury to SK-N-SH cells in vitro

Ischemic cerebral stroke is a leading cause of death and long-term disability world-wide. Neuronal injury following cerebral ischemia initiates a complex series of signaling cascades that lead to neuronal cell death. MicroRNA 29b (miR-29b) has reported involvement in the pathogenic process of ischemic brain injury. Dexmedetomidine (Dex) is a highly selective α₂ adrenergic receptor stimulant that exerts a protective effect on brain tissue. To determine whether Dex might directly influence miR-29b expression after an ischemic injury, human neuroblastoma SK-N-SH cells were subjected to oxygen-glucose deprivation (OGD) for the purpose of creating a neuronal injury model that mimics the effects of brain ischemia in vitro. Next, the association of miR-29b with the protective effect of Dex against ischemic brain injury was studied through the enhancement or inhibition of miR-29b expression by transfection with an miR-29b mimic or inhibitor. We demonstrated that Dex treatment could reduce miR-29b expression, increase cell viability, and inhibit cell apoptosis in the OGD-induced neuronal injury model in vitro. Furthermore, down-regulation of miR-29b expression produced effects on OGD-induced neuronal injuries that were similar to those produced by Dex treatment. Moreover, up-regulation of miR-29b reversed the protective effect of Dex treatment against OGD-induced neuronal injury. Therefore, down-regulation of miR-29b expression might play a role in anti-apoptotic signaling similar to that played by Dex. Elucidation of the role played by miR-29b in ischemia, and identification of a definite association between Dex and miR-29b may lead to the development of new strategies for treating ischemic brain injuries.

Restoration of miR-29b exerts anti-cancer effects on glioblastoma

Background

Glioblastoma multiforme (GBM) is known as one of the most fatal forms of cancer. MicroRNAs have been widely implicated in the regulation of mammalian development and pathogenesis. The brain-enriched miR-29 subfamilies are known to be exclusively expressed in the developing brain, and they are aberrantly down-regulated in GBM. This study aims to elucidate the role of miR-29b in GBM development and the feasibility of therapeutic targeting using conjugated nanoparticles.

Methods

After confirmation of miR-29b expression levels in GBM tissues by analysis of open source data, the anticancer effect of miR-29b was tested by the introduction of syn-hsa-miR-29b-3p in the A172 GBM cell line. In vitro studies of cell viability and apoptosis and ex vivo study using GBM tissue slice cultures from 3 patients and nanoparticle delivery of miR-29b were performed.

Results

We discovered an increase in apoptotic cell populations with the introduction of miR-29b in the GBM cell line. An established human-derived GBM tissue slice culture system confirmed the anticancer effect of miR-29b-conjugated nanoparticles. Using PCR array, we found that exogenous miR-29b inhibits the expression of COL1A2, COL3A1, COL4A1, ELN, ITGA11, MMP24, and SPARC, which mediates an anticancer effect.

Conclusions

miR-29b may serve as a putative therapeutic molecule when its expression is restored using a nanoparticle delivery system in GBM.

Down-regulated serum microRNA-101 is associated with aggressive progression and poor prognosis of cervical cancer

OBJECTIVE

MicroRNAs (miRNAs) play a vital role in pathogenesis and progression of many cancers, including cervical cancer. However, importance of serum level of miR-101 in cervical cancer has rarely been studied. In the present study, clinical significance and prognostic value of serum miR-101 for cervical cancer was investigated.

METHODS

Association between miR-101 level in cervical cancer tissues and prognosis of patients was analyzed by using data retrieved from The Cancer Genome Atlas (TCGA) database, which was followed with our clinical study in which miR-101 serum level comparison between cervical cancer patients and healthy controls was conducted by real-time quantitative polymerase chain reaction (PCR).

RESULTS

TCGA database demonstrated that miR-101 was down-regulated in cervical cancer tissues compared with normal cervical tissues, and univariate Cox regression analysis indicated that decreased miR-101 expression was a highly significant negative risk factor. Similar trend was found in the serum miR-101. Serum level of miR-101 was associated with International Federation of Gynecology and Obstetrics (FIGO) stage (p=0.003), lymph node metastasis (p=0.001), and serum squamous cell carcinoma antigen (SCC-Ag) level >4 (p=0.007). The overall survival time of cervical cancer patients with a higher level of serum miR-101 was significantly longer than that of patients with a lower level of serum miR-101. Moreover, multivariate Cox regression analysis indicated that the down-regulated serum level of miR-101 was an independent predictor for the unfavorable prognosis of cervical cancer.

CONCLUSION

Serum level of miR-101 is closely associated with metastasis and prognosis of cervical cancer; and, hence could be a potential biomarker and prognostic predictor for cervical cancer.

Analysis of primary microRNA loci from nascent transcriptomes reveals regulatory domains governed by chromatin architecture

Changes in mature microRNA (miRNA) levels that occur downstream of signaling cascades play an important role during human development and disease. However, the regulation of primary microRNA (pri-miRNA) genes remains to be dissected in detail. To address this, we followed a data-driven approach and developed a transcript identification, validation and quantification pipeline for characterizing the regulatory domains of pri-miRNAs. Integration of 92 nascent transcriptomes and multilevel data from cells arising from ecto-, endo- and mesoderm lineages reveals cell type-specific expression patterns, allows fine-resolution mapping of transcription start sites (TSS) and identification of candidate regulatory regions. We show that inter- and intragenic pri-miRNA transcripts span vast genomic regions and active TSS locations differ across cell types, exemplified by the mir-29a∼29b-1, mir-100∼let-7a-2∼125b-1 and miR-221∼222 clusters. Considering the presence of multiple TSS as an important regulatory feature at miRNA loci, we developed a strategy to quantify differential TSS usage. We demonstrate that the TSS activities associate with cell type-specific super-enhancers, differential stimulus responsiveness and higher-order chromatin structure. These results pave the way for building detailed regulatory maps of miRNA loci.

Advances in the Application and Impact of MicroRNAs as Therapies for Skin Disease

The advent of RNA interference (RNAi) technology has profoundly impacted molecular biology research and medicine but has also advanced the field of skin care. Both effector molecules of RNAi, short-interfering RNA molecules and microRNAs (miRNAs), have been explored for their relative impact and utility for treating a variety of skin conditions. These post-transcriptional RNA regulatory molecules down-modulate protein expression through targeting of the 3' untranslated regions of messenger RNAs, leading to their degradation or repression through sequestration. As researchers hunt for genetic linkages to skin diseases, miRNA regulators have emerged as key players in the biology of keratinocytes, fibroblasts, melanocytes, and other cells of the skin. Herein, we attempt to coalesce the current efforts to combat various skin disorders and diseases through the development of miRNA-based technologies.

Expression Profiling of MicroRNAs in the Inner Ear of Elderly People by Real-Time PCR Quantification

The molecular mechanisms underlying age-related hearing loss are unknown, and currently, there is no treatment for this condition. Recent studies have shown that microRNAs (miRNAs) and age-related diseases are intimately linked, suggesting that some miRNAs may present attractive therapeutic targets. In this study, we obtained 8 human temporal bones from 8 elderly subjects at brain autopsy in order to investigate the expression profile of miRNAs in the inner ear with miRNA arrays. A mean of 478 different miRNAs were expressed in the samples, of which 348 were commonly expressed in all 8 samples. Of these, levels of 16 miRNAs significantly differed between young elderly and old elderly subjects. miRNAs, which play important roles in inner ear development, were detected in all samples, i.e., in both young and old elderly subjects, whether with or without hearing loss. Our results suggest that these miRNAs play important roles not only in development, but also in the maintenance of inner ear homeostasis.

Tumor microenvironment and noncoding RNAs as co-drivers of epithelial-mesenchymal transition and cancer metastasis

Reciprocal interactions between cancer cells and tumor microenvironment (TME) are crucial events in tumor progression and metastasis. Pervasive stromal reprogramming of TME modifies numerous cellular functions, including extracellular matrix (ECM) stiffness, inflammation, and immunity. These environmental factors allow selection of more aggressive cells that develop adaptive strategies associating plasticity and epithelial-mesenchymal transition (EMT), stem-like phenotype, invasion, immunosuppression, and resistance to therapies. EMT is a morphomolecular process that endows epithelial tumor cells with mesenchymal properties, including reduced adhesion and increased motility. Numerous studies have demonstrated involvement of noncoding RNAs (ncRNAs), such as miRNAs and lncRNAs, in tumor initiation, progression, and metastasis. NcRNAs regulate every hallmark of cancer and have now emerged as new players in induction and regulation of EMT. The reciprocal regulatory interactions between ncRNAs, TME components, and cancer cells increase the complexity of gene expression and protein translation in cancer. Thus, deeper understanding of molecular mechanisms controlling EMT will not only shed light on metastatic processes of cancer cells, but enhance development of new therapies targeting metastasis. In this review, we will provide recent findings on the role of known ncRNAs relevant to EMT and cancer metastasis and discuss the role of the interaction between ncRNAs and TME as co-drivers of EMT. Developmental Dynamics 247:405-431, 2018. © 2017 Wiley Periodicals, Inc.

Identification of a p53 target, CD137L, that mediates growth suppression and immune response of osteosarcoma cells

p53 encodes a transcription factor that transactivates downstream target genes involved in tumour suppression. Although osteosarcoma frequently has p53 mutations, the role of p53 in osteosarcomagenesis is not fully understood. To explore p53-target genes comprehensively in calvarial bone and find out novel druggable p53 target genes for osteosarcoma, we performed RNA sequencing using the calvarial bone and 23 other tissues from p53^+/+ and p53^−/− mice after radiation exposure. Of 23,813 genes, 69 genes were induced more than two-fold in irradiated p53^+/+ calvarial bone, and 127 genes were repressed. Pathway analysis of the p53-induced genes showed that genes associated with cytokine-cytokine receptor interactions were enriched. Three genes, CD137L, CDC42 binding protein kinase gamma and Follistatin, were identified as novel direct p53 target genes that exhibited growth-suppressive effects on osteosarcoma cell lines. Of the three genes, costimulatory molecule Cd137l was induced only in calvarial bone among the 24 tissues tested. CD137L-expressing cells exhibited growth-suppressive effects in vivo. In addition, recombinant Fc-fusion Cd137l protein activated the immune response in vitro and suppressed osteosarcoma cell growth in vivo. We clarified the role of CD137L in osteosarcomagenesis and its potential therapeutic application. Our transcriptome analysis also indicated the regulation of the immune response through p53.

miR-29a/b/c function as invasion suppressors for gliomas by targeting CDC42 and predict the prognosis of patients

Background:

The lethality and poor outcome of high-grade gliomas result from the tumour relentless invasion. miR-29a/b/c downexpressions contribute to several human tumourigenesis. However, their relevance to prognosis and invasion in gliomas remains unclear.

Methods:

Relationships of miR-29a/b/c and CDC42 expressions to grade and survival-time in 147 human gliomas were analysed by in situ hybridisation and immunohistochemistry. Dual-luciferase reporter assay was used to identify CDC42 as a target of miR-29a/b/c. Underlining mechanisms by which miR-29a/b/c inhibited glioma cell migration and invasion were studied by in vitro and in vivo assays.

Results:

miR-29a/b/c expressions were inversely correlated with glioma grades, but positively correlated with patients’ survival. Two distinct subgroups of grade I–IV glioma patients with different prognoses were identified according to miR-29a/b/c expressions. miR-29a/b/c overexpressions suppressed glioma cell migration and invasion through targeting CDC42 and subsequently decreasing phosphorylated PAK1/2/3, LIMK1/2 and cofilin, the pivotal downstream effectors of CDC42. Moreover, CDC42 expression was positively correlated with glioma grades, but inversely correlated with miR-29a/b/c expressions and patients’ survival. In glioblastoma cell lines, CDC42-knockdown could mimic the anti-tumour effects of miR-29a/b/c.

Conclusions:

miR-29a/b/c are important tumour suppressors and novel prognostic biomarkers of gliomas, and miR-29a/b/c and CDC42 are potential therapeutic candidates for malignant gliomas.

High-Throughput Identification of miR-596 Inducing p53-Mediated Apoptosis in HeLa and HCT116 Cells Using Cell Microarray

miRNAs play a key role in the regulation of gene networks in mammalian cells. However, little is known about their roles and functions in the apoptosis pathway. Here, we conducted a whole-genome miRNA screening for apoptosis and identified more than 100 miRNAs as apoptosis inducers. To further explain the roles of these mRNAs in apoptosis, a second round of screening was conducted between p53 +/+ and -/- cells. Among the hits, miR-596 was identified as a regulator of p53. The overexpression of miR-596 significantly increased p53 at the protein level, thereby inducing apoptosis. We also demonstrated that Smurf1 was the direct target of miR-596. Previously, Smurf1 was reported to attenuate the level of p53 through binding and stabilizing MDM2, a p53 inhibitor. Consequently, by targeting Smurf1, miR-596 indirectly increased the p53 level in mammalian cells. Moreover, our study demonstrated that miR-596 had other antitumor characteristics, such as inhibiting migration and proliferation. The data from the GEO dataset revealed that the high expression of miR-596 contributed to survival benefits among cancer patients. These results make miR-596 a potential antitumor factor for future biomedical applications.

Prognostic value of the MicroRNA-29 family in multiple human cancers: A meta-analysis and systematic review

MicroRNAs (miRNAs) in cancer development have attracted much attention in recent years. miR-29 is known to critically affect cancer progression by functioning as a tumor suppressor. However, it may also act as an oncogene under certain situations. The prognostic value of the miR-29 family in cancer progression is still under debate and reported results are inconsistent. Therefore, we reported here a meta-analysis and systematic review to analyze the prognostic role of the miR-29 family in cancer. We screened 20 published studies and calculated pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for overall survival (OS) or disease-free survival/recurrence-free survival (DFS/RFS). Our results showed that a low or absent expression of miR-29 family was significantly associated with poor OS (HR, 1.57; 95%CI, 1.18-2.08), and inferior to 5-year DFS/RFS (HR, 1.89; 95%CI, 1.47-2.44). Analysis of individual miR-29 subtypes indicated that the low expression of miR-29a/b/c subtypes correlated with poor 5-year OS (miR-29a: HR, 1.99; 95%CI, 1.41-2.80; miR-29b: HR, 1.60; 95%CI, 1.18-2.17; miR-29c: HR, 1.69; 95%CI, 1.00-2.86), as well as poor 5-year DFS/RFS (miR-29b: HR, 1.70; 95%CI, 1.27-2.27). Ethnicity analysis demonstrated Asian patients with low expression of miR-29 were significantly correlated with poor OS (HR, 1.61; 95%CI, 1.16-2.23) and 5-year DFS/RFS (HR, 2.03; 95%CI, 1.50-2.74). Taken together, our analysis indicates that the low expression of miR-29 is associated with aggressiveness and poor prognosis of malignant neoplasms. More importantly, miR-29 might serve as a key biomarker for predicting the recurrence and progression of human cancers.

Implication of microRNAs in the development and potential treatment of radiation-induced heart disease

Radiotherapy is the most commonly used methodology to treat oncological disease, one of the most widespread causes of death worldwide. Oncological patients cured by radiotherapy applied to the mediastinal area have been shown to suffer from cardiovascular disease. The increase in the prevalence of radiation-induced heart disease has emphasized the need to seek new therapeutic targets to mitigate the negative impact of radiation on the heart. In this regard, microRNAs (miRNAs) have received considerable interest. miRNAs regulate post-transcriptional gene expression by their ability to target various mRNA sequences because of their imperfect pairing with mRNAs. It has been recognized that miRNAs modulate a diverse spectrum of cardiac functions with developmental, pathophysiological, and clinical implications. This makes them promising potential targets for diagnosis and treatment. This review summarizes the recent findings about the possible involvement of miRNAs in radiation-induced heart disease and their potential use as diagnostic or treatment targets in this respect.

Stress-responsive microRNAs are involved in re-programming of metabolic functions in hibernators

Mammalian hibernation includes re-programing of metabolic capacities, partially, encouraged by microRNAs (miRNAs). Albeit much is known about the functions of miRNAs, we need learning on low temperature miRNAs target determination. As hibernators can withstand low body temperatures (TB) for a long time without anguish tissue damage, understanding the means and mechanisms that empower them to do as such are of restorative intrigue. Nonetheless, these mechanisms by which miRNAs and the hibernators react to stressful conditions are not much clear. It is evident from recent data that the gene expression and the translation of mRNA to protein are controlled by miRNAs. The miRNAs also influence regulation of major cellular processes. As the significance of miRNAs in stress conditions adaptation are getting clearer, this audit article abridges the key alterations in miRNA expression and the mechanism that facilitates stress survival.

Hypoxia- and acidosis-driven aberrations of secreted microRNAs in endometrial cancer in vitro

Due to their post-transcriptional regulatory impact on gene expression, microRNAs (miRNA, miRs) influence decisively cellular processes of differentiation, proliferation and apoptosis. In oncogenic pathways various miRNAs exert either oncogenic or tumor suppressor activities in a stage-specific manner. Dysregulation of miRNA expression pattern has been associated with several human cancers including endometrial cancer (EC). In the present study, expression profile alterations of EC associated secreted miRNAs were determined under the microenvironmental stress situations hypoxia and acidosis occurring in tumor progression and metastasis. The potential influence of hypoxia and acidosis vs. control conditions on the expression levels of 24 EC-relevant miRNA types was quantitatively accessed via real-time PCR in three established EC in vitro models. Expression data were analyzed statistically. In vitro application of hypoxia resulted in downregulation of miR-15a, miR-20a, miR-20b and miR-128-1 in Ishikawa cells (type I EC) and upregulation of miR-21 in EFE-184 cells (type I EC). Acidosis triggered upregulation of tumor promoting miR-125b in AN3-CA cell (type II EC), whereas in Ishikawa cells (type I EC) miRNAs with tumor suppressive function were found altered in divergent directions, both up- (let-7a) and down- (miR-22) regulated. Our current findings emphasize the functional importance of secreted miRNAs in the immediate response of EC cells to exogenic stress situations such as the typical tumor epiphenomena hypoxia and acidosis. Focusing on the specific potential of secreted, thus circulating miRNA molecules, alterations in expression levels not only influence intracellular gene expression and signaling cascades, but also transfer the induction of (tumor)biological cellular changes to adjacent cells.

MicroRNA-29 Family Suppresses the Invasion of HT1080 Human Fibrosarcoma Cells by Regulating Matrix Metalloproteinase 2 Expression

Matrix metalloproteinase 2 (MMP2) is a potent protumorigenic, proangiogenic, and prometastatic enzyme that is overexpressed in metastatic cancer. Although there have been various studies on the MMP2 gene, further studies of regulatory factors are required to achieve inhibition of MMP2 enzyme activities. MicroRNAs (miRNAs) play key roles in tumor metastasis. However, the specific functions of miRNAs in metastasis are unclear. In this study, we assessed the function of the microRNA-29 family (miR-29s) in HT1080 human fibrosarcoma cells and examined the regulatory mechanisms of these miRNAs on MMP2 activation. Using miRanda, TargetScan, and PicTar databases, miR-29s were identified as candidate miRNAs targeting MMP2. Gain-of-function studies showed that overexpression of miR-29s could inhibit the invasion of HT1080 cells, suggesting their tumor-suppressive roles in HT1080 cells. In addition, dual luciferase reporter assays indicated that miR-29s could inhibit the expression of the luciferase gene containing the 3'-untranslated region of MMP2 mRNA. Ectopic expression of miR-29s down-regulated the expression of MMP2. Moreover, ectopic expression of miR-29s reduced MMP2 enzyme activity. These results suggested that miR-29s could decrease the invasiveness of HT1080 cells by modulating MMP2 signaling. Taken together, our results demonstrated that miR-29s may serve as therapeutic targets to control tumor metastasis.

MicroRNA-187 modulates epithelial-mesenchymal transition by targeting PTRF in non-small cell lung cancer

MicroRNAs (miRNAs) that negatively regulate gene expression play a key role in the development and progression of cancer. Aberrant expression of hsa-miR-187 (miR-187) has been reported in various malignancies. However, the function of miR-187 in tumor progression remains controversial and its role in non-small cell lung cancer (NSCLC) is poorly understood. In the present study, the role of miR-187 in the progression of NSCLC was investigated. Our results revealed that miR-187 was frequently upregulated in NSCLC tissues and cells. Furthermore, ectopic introduction of miR-187 promoted cell migration, whereas miR-187 inhibitor had the contrary effect in NSCLC cells. Of significance, miR-187 induced epithelial-mesenchymal transition (EMT), which plays a pivotal role in the initiation of metastasis and activated mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathways. Polymerase I and transcript release factor (PTRF) was identified as a direct target of miR-187 in the promotion of the migration of NSCLC cells. Restored expression of PTRF neutralized the promoting effect of miR-187 on cell migration and EMT of NSCLC cells. Collectively, our data highlight the pivotal role of miR-187 in the progression of NSCLC, indicating this factor as a potential candidate in molecular cancer therapy.

Chlamydia preserves the mitochondrial network necessary for replication via microRNA-dependent inhibition of fission

Chlamydiae are intracellular pathogens that depend on the host for their survival and development. Chowdhury et al. demonstrate that Chlamydia trachomatis infection can prevent mitochondrial fission in primary cells by reducing DRP1 abundance via miR-30c–dependent inhibition of p53.

Obligate intracellular bacteria such as Chlamydia trachomatis depend on metabolites of the host cell and thus protect their sole replication niche by interfering with the host cells’ stress response. Here, we investigated the involvement of host microRNAs (miRNAs) in maintaining the viability of C. trachomatis–infected primary human cells. We identified miR-30c-5p as a prominently up-regulated miRNA required for the stable down-regulation of p53, a major suppressor of metabolite supply in C. trachomatis–infected cells. Loss of miR-30c-5p led to the up-regulation of Drp1, a mitochondrial fission regulator and a target gene of p53, which, in turn, severely affected chlamydial growth and had a marked effect on the mitochondrial network. Drp1-induced mitochondrial fragmentation prevented replication of C. trachomatis even in p53-deficient cells. Additionally, Chlamydia maintain mitochondrial integrity during reactive oxygen species–induced stress that occurs naturally during infection. We show that C. trachomatis require mitochondrial ATP for normal development and hence postulate that they preserve mitochondrial integrity through a miR-30c-5p–dependent inhibition of Drp1-mediated mitochondrial fission.

Microscale Symmetrical Electroporator Array as a Versatile Molecular Delivery System

Successful developments of new therapeutic strategies often rely on the ability to deliver exogenous molecules into cytosol. We have developed a versatile on-chip vortex-assisted electroporation system, engineered to conduct sequential intracellular delivery of multiple molecules into various cell types at low voltage in a dosage-controlled manner. Micro-patterned planar electrodes permit substantial reduction in operational voltages and seamless integration with an existing microfluidic technology. Equipped with real-time process visualization functionality, the system enables on-chip optimization of electroporation parameters for cells with varying properties. Moreover, the system’s dosage control and multi-molecular delivery capabilities facilitate intracellular delivery of various molecules as a single agent or in combination and its utility in biological research has been demonstrated by conducting RNA interference assays. We envision the system to be a powerful tool, aiding a wide range of applications, requiring single-cell level co-administrations of multiple molecules with controlled dosages.

MicroRNA-29c-5p suppresses gallbladder carcinoma progression by directly targeting CPEB4 and inhibiting the MAPK pathway

Gallbladder cancer (GBC) is a leading cause of cancer-related deaths worldwide, and its prognosis remains poor, with a 5-year survival rate of ~5%. Given the crucial role of microRNAs (miRNAs) in cancer metastasis, we aimed to analyze the expression and function of the metastasis-associated miRNA miR-29c-5p in GBC.We validated that expression of miR-29c-5p was significantly downregulated in GBC and was closely associated with lymph node metastasis, overall survival and disease-free survival in 40 GBC patients who were followed clinically. Ectopic overexpression of miR-29c-5p dramatically repressed proliferation, metastasis, and colony formation and induced apoptosis in vitro, and it suppressed tumorigenicity in vivo through the MAPK pathway. Cytoplasmic polyadenylation element binding protein 4 (CPEB4) was identified as a critical effector target of miR-29c-5p. Enforced expression of miR-29c-5p significantly inhibited the expression of CPEB4, and restoration of CPEB4 expression reversed the inhibitory effects of miR-29c-5p on GBC cell proliferation and metastasis. Transforming growth factor-β (TGF-β) upregulated CPEB4 by downregulating miR-29c-5p, leading to MAPK pathway activation. In conclusion, the TGF-β/miR-29c-5p/CPEB4 axis has a pivotal role in the pathogenesis and poor prognosis of GBC, suggesting that miR-29c-5p is a tumor-suppressive miRNA that may serve as potential prognostic biomarker or therapeutic target for GBC.

miR-600 inhibits cell proliferation, migration and invasion by targeting p53 in mutant p53-expressing human colorectal cancer cell lines

Mutations of the tumor protein p53 gene, a tumor suppressor, are one of the most frequent genetic alterations observed in cancer. It has been reported that mutations in p53 result in the loss of wild-type p53 activity, and the gain of novel oncogenic properties that promote tumor growth and progression. Recent studies have demonstrated that a number of microRNAs (miRs) are involved in the post-transcriptional regulation of p53. The present study demonstrates that miR-600 is a direct negative regulator of p53 through binding a site in the 3' untranslated region of p53 mRNA in human colorectal cancer (CRC) cells. Overexpression of miR-600 by lentiviral-mediated transduction decreased endogenous levels of p53 protein and inhibited cell proliferation, migration and invasion in mutant p53-expressing human CRC cell lines (SW480, SW620 and DLD-1) in vitro. In addition, silencing of p53 with small interfering RNA led to a similar phenotype. Furthermore, overexpression of miR-600 or p53 knockdown suppressed the expression of matrix metalloproteinase 9, and promoted the expression of E-cadherin and β-catenin. The results of the current study demonstrate that miR-600 is an important negative regulator of p53, and suggest that targeting mutant p53 using lentiviral-mediated miR-600 overexpression is a promising therapeutic strategy for the treatment of CRCs with p53 mutations.

Supercritical-Carbon Dioxide Fluid Extract from Chrysanthemum indicum Enhances Anti-Tumor Effect and Reduces Toxicity of Bleomycin in Tumor-Bearing Mice

Bleomycin (BLM), a family of anti-tumor drugs, was reported to exhibit severe side effects limiting its usage in clinical treatment. Therefore, finding adjuvants that enhance the anti-tumor effect and reduce the detrimental effect of BLM is a prerequisite. Chrysanthemum indicum, an edible flower, possesses abundant bioactivities; the supercritical-carbon dioxide fluid extract from flowers and buds of C. indicum (CI_SCFE) have strong anti-inflammatory, anti-oxidant, and lung protective effects. However, the role of CI_SCFE combined with BLM treatment on tumor-bearing mice remains unclear. The present study aimed to investigate the potential synergistic effect and the underlying mechanism of CI_SCFE combined with BLM in the treatment of hepatoma 22 (H22) tumor-bearing mice. The results suggested that the oral administration of CI_SCFE combined with BLM could markedly prolong the life span, attenuate the BLM-induced pulmonary fibrosis, suppress the production of pro-inflammatory cytokines (interleukin-6), tumor necrosis factor-α, activities of myeloperoxidase, and malondiadehyde. Moreover, CI_SCFE combined with BLM promoted the ascites cell apoptosis, the activities of caspases 3 and 8, and up-regulated the protein expression of p53 and down-regulated the transforming growth factor-β1 by activating the gene expression of miR-29b. Taken together, these results indicated that CI_SCFE could enhance the anti-cancer activity of BLM and reduce the BLM-induced pulmonary injury in H22 tumor-bearing mice, rendering it as a potential adjuvant drug with chemotherapy after further investigation in the future.

Regulation of hepatic microRNA expression by hepatocyte nuclear factor 4 alpha

AIM

To uncover the role of hepatocyte nuclear factor 4 alpha (HNF4α) in regulating hepatic expression of microRNAs.

METHODS

Microarray and real-time PCR were used to determine hepatic expression of microRNAs in young-adult mice lacking Hnf4α expression in liver (Hnf4α-LivKO). Integrative genomics viewer software was used to analyze the public chromatin immunoprecipitation-sequencing datasets for DNA-binding of HNF4α, RNA polymerase-II, and histone modifications to loci of microRNAs in mouse liver and human hepatoma cells. Dual-luciferase reporter assay was conducted to determine effects of HNF4α on the promoters of mouse and human microRNAs as well as effects of microRNAs on the untranslated regions (3’UTR) of two genes in human hepatoma cells.

RESULTS

Microarray data indicated that most microRNAs remained unaltered by Hnf4α deficiency in Hnf4α-LivKO mice. However, certain liver-predominant microRNAs were down-regulated similarly in young-adult male and female Hnf4α-LivKO mice. The down-regulation of miR-101, miR-192, miR-193a, miR-194, miR-215, miR-802, and miR-122 as well as induction of miR-34 and miR-29 in male Hnf4α-LivKO mice were confirmed by real-time PCR. Analysis of public chromatin immunoprecipitation-sequencing data indicates that HNF4α directly binds to the promoters of miR-101, miR-122, miR-194-2/miR-192 and miR-193, which is associated with histone marks of active transcription. Luciferase reporter assay showed that HNF4α markedly activated the promoters of mouse and human miR-101b/miR-101-2 and the miR-194/miR-192 cluster. Additionally, miR-192 and miR-194 significantly decreased activities of luciferase reporters for the 3’UTR of histone H3F3 and chromodomain helicase DNA binding protein 1 (CHD1), respectively, suggesting that miR-192 and miR-194 might be important in chromosome remodeling through directly targeting H3F3 and CHD1.

CONCLUSION

HNF4α is essential for hepatic basal expression of a group of liver-enriched microRNAs, including miR-101, miR-192, miR-193a, miR-194 and miR-802, through which HNF4α may play a major role in the post-transcriptional regulation of gene expression and maintenance of the epigenome in liver.

microRNA-29c inhibits cell proliferation by targeting NASP in human gastric cancer

Background

Gastric cancer is one of the most common malignancies worldwide. Recent studies have shown that microRNAs play crucial roles in regulating cellular proliferation process in gastric cancer. MicroRNA-29c (miR-29c) acts as a tumor suppressor in different kinds of tumors.

Methods

Quantitative PCR was performed to evaluate miR-29c expression level in 67 patient gastric cancer tissues and 9 gastric cancer cell lines. The effects of miR-29c were explored by proliferation assay, soft agar colony formation assay, apoptosis and cell cycle analysis using flow cytometry. The target gene was predicted by bioinformatic algorithms and validated by dual luciferase reporter assay and Western blot analysis.

Results

In this study, we demonstrate that miR-29c is down-regulated in gastric cancer tissues and cell lines. We indicate that overexpression of miR-29c inhibits cell proliferation, promotes apoptosis and arrests cell cycle at G1/G0 phase. We additionally show that miR-29c exerts these effects by targeting Nuclear autoantigenic sperm protein (NASP). Moreover, depletion of NASP can elite the phenotypes caused by miR-29c.

Conclusions

These data suggest that miR-29c inhibits proliferation in gastric cancer and could potentially serve as an early biomarker and a novel therapy target.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3096-9) contains supplementary material, which is available to authorized users.

mir-660-p53-mir-486 Network: A New Key Regulatory Pathway in Lung Tumorigenesis

Lung cancer is the most frequent cause of cancer-related death worldwide, with limited therapeutic options and rapid development of drug resistance. MicroRNAs, a class of small non-coding RNAs that control different physiological processes, have been associated with cancer development, as either oncomiRNAs or tumor-suppressor miRNAs. In the present study we investigated the interaction between mir-486-5p and mir-660-5p, two independent tumor-suppressor miRNAs, to assess their possible role and synergistic effect in lung cancer treatment. Our data show that mir-660-5p over-expression in A549 lung cancer cells induced a remarkable increase in mir-486-5p expression level and activity, detected as a reduction of its target gene, p85. mir-486-5p expression was confirmed by microRNA in situ hybridization. mir-660-5p modulated mir-486-5p through the silencing of Mouse Double Minute 2 (MDM2), one of its direct target, and then through p53 stimulation. This regulatory pathway was effective in A549, but not in H1299; therefore, only in the context of a functional p53 protein. Our findings support the conclusion that mir-486-5p is positively regulated by mir-660-5p in lung cancer cell lines, through the mir-660-MDM2-p53 pathway, making mir-660-5p even more interesting for its potential successful use in lung cancer therapy.

Generation of a Floxed Allele of the Mouse MicroRNA-200 Clusters

MicroRNA-8 and its target gene, u-shaped (ush), regulate body size in Drosophila. As the mouse homolog of the Drosophila miR-8, whether the miR-200 family has similar functions and how they perform their regulatory roles in body size control is unknown. In order to discover the biological function of the miR-200s in vivo, we generated mice lacking the miR-200b/200a/429 gene cluster using the Cre/loxp system. miR-200b/200a/429 null mutant mice were viable, fertile, and showed normal development.

Androgen receptor (AR) promotes clear cell renal cell carcinoma (ccRCC) migration and invasion via altering the circHIAT1/miR-195-5p/29a-3p/29c-3p/CDC42 signals

Increasing evidence has demonstrated that the androgen receptor (AR) plays important roles to promote the metastasis of clear cell renal cell carcinoma (ccRCC). The detailed mechanisms, especially how AR functions via altering the circular RNAs (circRNAs) remain unclear. Here we identified a new circRNA (named as circHIAT1) whose expression was lower in ccRCCs than adjacent normal tissues. Targeting AR could suppress ccRCC cell progression via increasing circHIAT1 expression. ChIP assay and luciferase assay demonstrated that AR suppressed circHIAT1 expression via regulating its host gene, Hippocampus Abundant Transcript 1 (HIAT1) expression at the transcriptional level. The consequences of AR-suppressed circHIAT1 resulted in deregulating miR-195-5p/29a-3p/29c-3p expressions, which increased CDC42 expression to enhance ccRCC cell migration and invasion. Increasing this newly identified signal via circHIAT1 suppressed AR-enhanced ccRCC cell migration and invasion. Together, these results suggested that circHIAT1 functioned as a metastatic inhibitor to suppress AR-enhanced ccRCC cell migration and invasion. Targeting this newly identified AR-circHIAT1-mediated miR-195-5p/29a-3p/29c-3p/CDC42 signals may help us develop potential new therapies to better suppress ccRCC metastasis.

Regulation of miRNAs by herbal medicine: An emerging field in cancer therapies

MicroRNAs' expression profiles have recently gained major attention as far as cancer research is concerned. MicroRNAs are able to inhibit target gene expression via binding to the 3' UTR of target mRNA, resulting in target mRNA cleavage or translation inhibition. MicroRNAs play significant parts in a myriad of biological processes; studies have proven, on the other hand, that aberrant microRNA expression is, more often than not, associated with the growth and progression of cancers. MicroRNAs could act as oncogenes (oncomir) or tumor suppressors and can also be utilized as biomarkers for diagnosis, prognosis, and cancer therapy. Recent studies have shown that such herbal extracts as Shikonin, Sinomenium acutum, curcumin, Olea europaea, ginseng, and Coptidis Rhizoma could alter microRNA expression profiles through inhibiting cancer cell development, activating the apoptosis pathway, or increasing the efficacy of conventional cancer therapeutics. Such findings patently suggest that the novel specific targeting of microRNAs by herbal extracts could complete the restriction of tumors by killing the cancerous cells so as to recover survival results in patients diagnosed with malignancies. In this review, we summarized the current research about microRNA biogenesis, microRNAs in cancer, herbal compounds with anti-cancer effects and novel strategies for employing herbal extracts in order to target microRNAs for a better treatment of patients diagnosed with cancer.

Role of miRNAs in the pathogenesis and susceptibility of diabetes mellitus

MicroRNAs (miRNAs) are noncoding RNAs of ~22 nucleotides that regulate gene expression post-transcriptionally by binding to the 3' untranslated region of messenger RNA (mRNAs), resulting in inhibition of translation or mRNA degradation. miRNAs have a key role in fine-tuning cellular functions such as proliferation, differentiation and apoptosis, and they are involved in carcinogenesis, glucose homeostasis, inflammation and other biological processes. In this review, we focus on the role of miRNAs in the pathophysiology of the metabolic disease and diabetes mellitus, the hallmark of which is hyperglycemia caused by defective insulin secretion and/or action. A growing number of studies have revealed the association between miRNAs and the processes of insulin production and secretion in pancreatic β cells. In addition, aberrant expression of miRNAs in skeletal muscle, adipose tissue and liver has also been reported. Intriguingly, the tumor suppressor p53 has been implicated in the pathogenesis of diabetes in association with a number of miRNAs, suggesting that a p53/miRNA pathway might be a therapeutic target. Moreover, data from genome-wide association studies have revealed that several miRNA target sequences overlap type 2 diabetes susceptibility loci. Finally, the recent discovery of circulating miRNAs associated with diabetes onset/progression suggests the potential use of miRNAs as biomarkers.

gga-miR-2127 downregulates the translation of chicken p53 and attenuates chp53-mediated innate immune response against IBDV infection

Infectious bursal disease (IBD) is characterized by the immune suppression of infected birds. The molecular mechanism by which IBD virus (IBDV) suppresses the host immune system remains to be elucidated. The tumor suppressor protein p53 can inhibit the replication of various viruses, but its effect on IBDV remains unknown. This study established an in vitro infection model based on DF-1 cells (chicken embryo fibroblast cell line) to investigate the antiviral effects of chicken p53 (chp53) on IBDV infection. The expression level and activity of chp53 remarkably increased in IBDV-infected DF-1 cells. The overexpression of chp53 inhibited IBDV replication and upregulated the expression of multiple chicken antiviral innate immunity genes (IPS-1, IRF3, PKR, OAS, and Mx), whereas the suppression of chp53 led to the opposite effect. This result indicates that chp53 activates the antiviral innate immune response of chickens to IBDV infection. Bioinformatics analysis and dual-luciferase reporter assay showed that gga-miR-2127 targeted the 3'UTR of chp53. qRT-PCR and western blot revealed that gga-miR-2127 overexpression in DF-1 cells not only downregulated the expression levels of chp53 and of the antiviral innate immunity genes in chickens but also promoted IBDV replication. Our results suggest that gga-miR-2127 downregulates chp53 mRNA translation by targeting its 3'UTR and attenuates chp53-mediated antiviral innate immune response against IBDV.

Roles of TP53 in determining therapeutic sensitivity, growth, cellular senescence, invasion and metastasis

TP53 is a critical tumor suppressor gene that regulates cell cycle progression, apoptosis, cellular senescence and many other properties critical for control of normal cellular growth and death. Due to the pleiotropic effects that TP53 has on gene expression and cellular physiology, mutations at this tumor suppressor gene result in diverse physiological effects. T53 mutations are frequently detected in numerous cancers. The expression of TP53 can be induced by various agents used to treat cancer patients such as chemotherapeutic drugs and ionizing radiation. Radiation will induce Ataxia telangiectasia mutated (ATM) and other kinases that results in the phosphorylation and activation of TP53. TP53 is also negatively regulated by other mechanisms, such as ubiquitination by ligases such as MDM2. While TP53 has been documented to control the expression of many "classical" genes (e.g., p21^Cip-1, PUMA, Bax) by transcriptional mechanisms for quite some time, more recently TP53 has been shown to regulate microRNA (miR) gene expression. Different miRs can promote oncogenesis (oncomiR) whereas others act to inhibit tumor progression (tumor suppressor miRs). Targeted therapies to stabilize TP53 have been developed by various approaches, MDM2/MDM4 inhibitors have been developed to stabilize TP53 in TP53-wild type (WT) tumors. In addition, small molecules have been isolated that will reactivate certain mutant TP53s. Both of these types of inhibitors are in clinical trials. Understanding the actions of TP53 may yield novel approaches to suppress cancer, aging and other health problems.

Rho GTPases: Regulation and roles in cancer cell biology

Rho GTPases are well known for their roles in regulating cell migration, and also contribute to a variety of other cellular responses. They are subdivided into 2 groups: typical and atypical. The typical Rho family members, including RhoA, Rac1 and Cdc42, cycle between an active GTP-bound and inactive GDP-bound conformation, and are regulated by GEFs, GAPs and GDIs, whereas atypical Rho family members have amino acid substitutions that alter their ability to interact with GTP/GDP and hence are regulated by different mechanisms. Both typical and atypical Rho GTPases contribute to cancer progression. In a few cancers, RhoA or Rac1 are mutated, but in most cancers expression levels and/or activity of Rho GTPases is altered. Rho GTPase signaling could therefore be therapeutically targeted in cancer treatment.

Roles and mechanisms of action of microRNAs in colorectal cancer

MicroRNAs (miRNAs) are a class of endogenous, evolutionarily conserved small non-coding RNAs, which play a vital role in tumour formation, development, metastasis and recurrence by inducing DNA methylation, changing tumor microenvironment and regulating signal pathways such as Wnt/β-catenin, phosphoinositide3-kinase (PI3K), K-RAS, epithelial mesenchymal transitions (EMT) and so on. Recent studies have found that the expression of many miRNAs is dyregulated in colorectal cancer, and they participate in and control the formation and development of colorectal cancer. Thus, understanding the roles and mechanisms of action of miRNAs in colorectal cancer can provide a new avenue for its early diagnosis, clinical staging, treatment and prognosis evaluation.

Novel miR-5582-5p functions as a tumor suppressor by inducing apoptosis and cell cycle arrest in cancer cells through direct targeting of GAB1, SHC1, and CDK2

MicroRNAs (miRNAs) play pivotal roles in tumorigenesis as either tumor suppressors or oncogenes. In the present study, we discovered and demonstrated the tumor suppressive function of a novel miRNA miR-5582-5p. miR-5582-5p induced apoptosis and cell cycle arrest in cancer cells, but not in normal cells. GAB1, SHC1, and CDK2 were identified as direct targets of miR-5582-5p. Knockdown of GAB1/SHC1 or CDK2 phenocopied the apoptotic or cell cycle arrest-inducing function of miR-5582-5p, respectively. The expression of miR-5582-5p was lower in tumor tissues than in adjacent normal tissues of colorectal cancer patients, while the expression of the target proteins exhibited patterns opposite to that of miR-5582-5p. Intratumoral injection of a miR-5582-5p mimic or induced expression of miR-5582-5p in tumor cells suppressed tumor growth in HCT116 xenografts. Collectively, our results suggest a novel tumor suppressive function for miR-5582-5p and its potential applicability for tumor control.

Expression profiles of miR-29c, miR-200b and miR-375 in tumour and tumour-adjacent tissues of head and neck cancers

Altered expression of microRNAs (miRNAs) has been shown in many types of malignancies including the head and neck squamous cell carcinoma (HNSCC). Although there are many new and innovative approaches in the treatment of HNSCC, a clear marker of this disease is still missing. Three candidate miRNAs (miR-29c-3p, miR-200b-5p and miR-375-3p) were studied in connection with HNSCC using quantitative real-time PCR expression levels in 42 tissue samples of HNSCC patients and histologically normal tumour-adjacent tissue samples of these patients. Primary HNSCC carcinoma tissues can be distinguished from histologically normal-matched noncancerous tumour-adjacent tissues based on hsa-miR-375-3p expression (sensitivity 87.5 %, specificity 65 %). Additionally, a significant decrease of hsa-miR-200b-5p expression was revealed in tumour-adjacent tissue samples of patients with node positivity. Lower expression of hsa-miR-200b-5p and hsa-miR-29c-3p in HNSCC tumour tissue was associated with higher tumour grade. Consequently, survival analysis was performed. Lower expression of hsa-miR-29c-3p in tumour-adjacent tissue was associated with worse overall and disease-specific survivals. Lower expression of miR-29c-3p in tumourous tissue was associated with worse relapse-free survival. hsa-miR-375-3p seems to be a relatively promising diagnostic marker in HNSCC but is not suitable for prognosis of patients. Furthermore, this study highlighted the importance of histologically normal tumour-adjacent tissue in HNSCC progress (significant decrease of hsa-miR-200b-5p expression in tumour-adjacent tissue of patients with node positivity and low expression of hsa-miR-29c-3p in HNSCC tumour-adjacent tissue associated with worse prognosis).

An Amphiphilic Peptide Induces Apoptosis Through the miR29b-p53 Pathway in Cancer Cells

Peptides have been in the limelight, as therapeutic agents for cancer treatment through various applications due to their high target selectivity and exceptional ability to penetrate the cell membrane. Recent studies have revealed that synthesized peptides bind to hairpin structures of RNA that affect their activities such as changing the efficacy of microRNA maturation. MicroRNA-mediated p53 activation by the microRNA-29 (miR29) family is one of the most important regulatory pathways in cancer therapeutics. By targeting the suppressors of p53, a tumor suppressor protein, miR29 induces apoptosis of cancer cells through p53 stabilization. Here, we identify a novel synthesized amphiphilic peptide, LK-L1C/K6W/L8C, which enhances expression of miR29b and promotes p53 activity. In the presence of LK-L1C/K6W/L8C, pre-miR29b preferentially forms a complex with the Dicer protein through interaction of LK-L1C/K6W/L8C with the terminal loop region of pre-miR29b, leading to an increase in Dicer processing. Furthermore, LK-L1C/K6W/L8C stimulates apoptosis by improving p53 stability in miR29-inducible HeLa and MCF7 cells. Collectively, our study shows that a peptide can directly influence the miR29b-mediated p53 activation pathway in cancer cells. Therefore, our findings provide the basis for a new, potentially promising peptide-based drug for cancer therapy.

The correlation between miR-200c and the severity of interstitial lung disease associated with different connective tissue diseases

OBJECTIVES

To explore the correlation between microRNA (miR)-200c and the severity of interstitial lung disease (ILD) associated with connective tissue diseases (CTDs).

METHOD

We recruited 218 patients with CTDs who were evaluated with high-resolution computed tomography (HRCT) and the pulmonary function test (PFT). Peripheral blood mononuclear cells (PBMCs) were acquired from 23 patients with systemic sclerosis (SSc), 29 with dermatomyositis/polymyositis (DM/PM), 30 with primary Sjögren's syndrome (pSS), 47 with rheumatoid arthritis (RA), and 23 normal controls to detect the expression level of miR-200c by quantitative reverse transcription polymerase chain reaction (QRT-PCR). miR-200c levels were compared among the different disease groups, between the group with ILD (CTD+ILD) and the group without ILD (CTD-ILD), and between mild and severe ILD groups. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were compared among the different CTD groups and the different CTD+ILD groups.

RESULTS

The miR-200c level in the SSc group was significantly higher than in the DM/PM, pSS, and RA groups, and the levels in the DM/PM and pSS groups were significantly higher than in the RA group. The level of miR-200c in the CTD+ILD group was significantly higher than in the CTD-ILD group, and the level in the severe ILD group was significantly higher than in the mild ILD group. FVC and FEV1 were significantly different among the different CTD groups, and among the different CTD+ILD groups. There was a negative correlation between the level of miR-200c and FVC and FEV1.

CONCLUSIONS

The level of miR-200c was positively correlated with the severity of ILD, and miR-200c in PBMCs could be a biomarker of the severity of ILD in CTDs.

MicroRNA Control of p53

Tumor suppressor p53 plays a central role in tumor suppression. As a transcription factor, p53 mainly exerts its tumor suppressive function through transcriptional regulation of many target genes. To maintain the proper function of p53, p53 protein level and activity are exquisitely controlled by a group of positive and negative regulators in cells. Thus, p53, its regulators, and regulated genes form a complicated p53 signaling network. microRNAs (miRNAs) are a group of endogenous small non-coding RNA molecules. miRNAs play an important role in regulation of gene expression by blocking translational protein synthesis and/or degrading target mRNAs. Recent studies have demonstrated that p53 and its network are regulated by miRNAs at multiple levels. Some miRNAs regulate the level and function of p53 through directly targeting p53, whereas some other miRNAs target regulators of p53, such as MDM2 and MDM4, to indirectly regulate the activity and function of p53. On the other hand, p53 also regulates the transcriptional expression and the biogenesis of a group of miRNAs, which contributes to the tumor suppressive function of p53. p53 is the most frequently mutated gene in human cancer. Many tumor-associated mutant p53, which have "gain-of-function" activities in tumorigenesis independently of wild type p53, can regulate the expression of different miRNAs and modulate the biogenesis of specific miRNAs to promote tumorigenesis. These findings have demonstrated that miRNAs are important regulators and mediators of p53 and its signaling pathway, which highlights a pivotal role of miRNAs in the p53 network and cancer. J. Cell. Biochem. 118: 7-14, 2017. © 2016 Wiley Periodicals, Inc.

miR-29a up-regulation in AR42J cells contributes to apoptosis via targeting TNFRSF1A gene

AIM: To investigate the expression of miR-29a in rat acute pancreatitis and its functional role in AR42J cell apoptosis.

METHODS: Twelve SD rats were divided into a control group and an acute edematous pancreatitis (AEP) group randomly. AEP was induced by intraperitoneal injection of L-arginine (150 mg/kg) in the AEP group and equal volume of 0.9% NaCl was injected in the control group. The apoptosis of acinar cells in pancreatic tissue was determined by TUNEL assay. miRNA chip assay was performed to examine the expression of miRNAs in two groups. Besides, to further explore the role of miR-29a in apoptosis in vitro, recombinant rat TNF-α (50 ng/mL) was administered to treat the rat pancreatic acinar cell line AR42J for inducing AR42J cell apoptosis. Quantitative real-time PCR (qRT-PCR) was adopted to measure miR-29a expression. Then, miRNA mimic, miRNA antisense oligonucleotide (AMO) and control vector were used to transfect AR42J cells. The expression of miR-29a was confirmed by qRT-PCR and the apoptosis rate of AR42J cells was detected by flow cytometry analysis. Western blot was used to detect the expression of activated caspase3. Moreover, we used bioinformatics software and luciferase assay to test whether TNFRSF1A was the target gene of miR-29a. After transfection, qRT-PCR and Western blot was used to detect the expression of TNFRSF1A in AR42J cells after transfection.

RESULTS: The expression of miR-29a was much higher in the AEP group compared with the control group as displayed by the miRNA chip assay. After inducing apoptosis of AR42J cells in vitro, the expression of miR-29a was significantly increased by 1.49 ± 0.04 times in comparison with the control group. As revealed by qRT-PCR assay, the expression of miR-29a was 2.68 ± 0.56 times higher in the miR-29a mimic group relative to the control vector group, accompanied with an obviously increased acinar cell apoptosis rate (42.83 ± 1.25 vs 24.97 ± 0.15, P < 0.05). Moreover, the expression of miR-29a in the miRNA AMO group was 0.46 ± 0.05 times lower than the control vector group, and the cell apoptosis rate was much lower accordingly (17.27 ± 1.36 vs 24.97 ± 0.15, P < 0.05). The results of bioinformatics software and luciferase assay showed that TNFRSF1A might be a target gene of miR-29a. TNFRSF1A expression was up-regulated in the miR-29a mimic group, while the miR-29a AMO group showed the reverse trend.

CONCLUSION: miR-29a might promote the apoptosis of AR42J cells via up-regulating the expression of its target gene TNFRSF1A.

miR-29b attenuates tumorigenicity and stemness maintenance in human glioblastoma multiforme by directly targeting BCL2L2

Glioblastoma multiforme (GBM) is the most common malignant brain tumor and exhibits aggressive and invasive behavior. We previously identified four miRNAs—miR-29b, 494, 193a-3p, and 30e—with enhanced expression in GBM following treatment of ionizing radiation by miRNA microarray analysis. In this study, we found that only miR-29b inhibited tumor cell migration and invasion by reducing MMP-2 activity via phospho-AKT/β-catenin signaling, and stimulated a more epithelial-like morphology. Moreover, miR-29b inhibits angiogenesis by attenuating tube formation and the expression of VEGF and Ang-2, and stemness maintenance in GBM cells, as demonstrated by decreasing neurosphere formation and cancer stem cell marker protein expression. These findings support the anti-tumor properties of miR-29b in human GBM cells. Furthermore, miR-29b expression was inversely proportional to that of BCL2L2 mRNA or protein in various cancer cell types. Interestingly, BCL2L2 mRNA is highly expressed in the mesenchymal type of GBM. To further elucidate the relationship between miR-29b and BCL2L2 in GBM, we performed co-transfection reporter assays and determined that miR-29b downregulates BCL2L2 expression by directly binding its 3′UTR. Finally, we confirmed that BCL2L2 repression is of central importance to miR-29b anti-tumor activity using functional assays to examine cell migration, invasion, angiogenesis, and stemness. From these data, we propose that miR-29b may be a useful therapeutic agent in GBM.

MicroRNAs as novel therapeutic targets to treat kidney injury and fibrosis

MicroRNAs (miRs), a class of small noncoding RNAs that act as post-transcriptional regulators of gene expression, have attracted increasing attention as critical regulators of organogenesis, cancer, and disease. Interest has been spurred by development of a novel class of synthetic RNA oligonucleotides with excellent drug-like properties that hybridize to a specific miR, preventing its action. In kidney disease, a small number of miRs are dysregulated. These overlap with regulated miRs in nephrogenesis and kidney cancers. Several dysregulated miRs have been identified in fibrotic diseases of other organs, representing a "fibrotic signature," and some of these fibrotic miRs contribute remarkably to the pathogenesis of kidney disease. Chronic kidney disease, affecting ∼10% of the population, leads to kidney failure, with few treatment options. Here, we will explore the pathological mechanism of miR-21, whose pre-eminent role in amplifying kidney disease and fibrosis by suppressing mitochondrial biogenesis and function is established. Evolving roles for miR-214, -199, -200, -155, -29, -223, and -126 in kidney disease will be discussed, and we will demonstrate how studying functions of distinct miRs has led to new mechanistic insights for kidney disease progression. Finally, the utility of anti-miR oligonucleotides as potential novel therapeutics to treat chronic disease will be highlighted.

Rho GTPase signaling promotes constitutive expression and release of TGF-β2 by human trabecular meshwork cells

Elevated intraocular pressure (IOP) is causally implicated in the pathophysiology of primary open-angle glaucoma (POAG). The molecular mechanisms responsible for elevated IOP remain elusive, but may involve aberrant expression and signaling of transforming growth factor (TGF)-β2 within the trabecular meshwork (TM). Consistent with previously published studies, we show here that exogenous addition of TGF-β2 to cultured porcine anterior segments significantly attenuates outflow facility in a time-dependent manner. By comparison, perfusing segments with a TGFβRI/ALK-5 antagonist (SB-431542) unexpectedly elicited a significant and sustained increase in outflow facility, implicating a role for TM-localized constitutive expression and release of TGF-β2. Consistent with this thesis, cultured primary or transformed (GTM3) quiescent human TM cells were found to constitutively express and secrete measurable amounts of biologically-active TGF-β2. Disrupting monomeric GTPase post-translational prenylation and activation with lovastatin or GGTI-298 markedly reduced constitutive TGF-β2 expression and release. Specifically, inhibiting the Rho subfamily of GTPases with C3 exoenzyme similarly reduced constitutive expression and secretion of TGF-β2. These findings suggest that Rho GTPase signaling, in part, regulates constitutive expression and release of biologically-active TGF-β2 from human TM cells. Localized constitutive expression and release of TGF-β2 by TM cells may promote or exacerbate elevation of IOP in POAG.

New Concepts in Cancer Biomarkers: Circulating miRNAs in Liquid Biopsies

The effective and efficient management of cancer patients relies upon early diagnosis and/or the monitoring of treatment, something that is often difficult to achieve using standard tissue biopsy techniques. Biological fluids such as blood hold great possibilities as a source of non-invasive cancer biomarkers that can act as surrogate markers to biopsy-based sampling. The non-invasive nature of these “liquid biopsies” ultimately means that cancer detection may be earlier and that the ability to monitor disease progression and/or treatment response represents a paradigm shift in the treatment of cancer patients. Below, we review one of the most promising classes of circulating cancer biomarkers: microRNAs (miRNAs). In particular, we will consider their history, the controversy surrounding their origin and biology, and, most importantly, the hurdles that remain to be overcome if they are really to become part of future clinical practice.

Erratum to: Negative feedback of miR-29 family TET1 involves in hepatocellular cancer

Primary hepatocellular carcinoma (HCC) is the most common form of liver cancer and is one of the most common malignancies worldwide. Tumor suppressor gene silencing through DNA methylation contributes to cancer formation. The ten-eleven translocations (TET) family of α-ketogluta-rate-dependent dioxygenases catalyzes the sequential oxidation of 5-methylcytosine to 5-hydroxymethyl-cytosine, 5-formylcytosine and 5-carboxylcytosine, leading to eventual DNA demethylation. MicroRNAs are an abundant class of 17-25 nucleotides small noncoding RNAs, identified as important regulators of many diverse biological processes. In this study, we showed that TET1 expression was obviously reduced in the majority of examined HCC tissues. And we further investigated the expression and functional involvement of TET1 in proliferation, migration and invasion and determined that TET1 may function as a tumor suppressor. miR-29b was proved to inhibit metastasis through the targeting of TET1, indicating that downregulation of miR-29 may involve in HCC carcinogenesis and progression through potentiation of TET1 expression. Thus, we elucidated the roles of feedback of miR-29-TET1 downregulation in HCC development and suggested a potential target in identification of the prognosis and application of cancer therapy for HCC patients.