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Background Circular RNAs (circRNAs) are implicated in the development of oral squamous cell carcinoma (OSCC). The aim of current research is to elucidate the role and mechanism of circ_0011946 in the functional behaviors of OSCC cells. Methods Circ_0011946, microRNA (miR)-216a-5p, B cell lymphoma-2-like 2 protein (BCL2L2) abundances were exposed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) or western blot. Cell proliferation, migration, invasion and apoptosis were detected by MTT, colony formation assay, transwell, wound-healing and flow cytometry assays, respectively. Target correlation was tested by dual-luciferase reporter and RNA pull-down assays. An in vivo xenograft experiment was employed to investigate the function of circ_0011946 on tumor growth in vivo. Results Circ_0011946 and BCL2L2 levels were increased, while miR-216a-5p level was decreased in OSCC tissues and cells. Circ_0011946 knockdown impeded proliferation, migration, and invasion, but promoted apoptosis in OSCC cells. Circ_0011946 functioned as a sponge for miR-216a-5p, and BCL2L2 was targeted by miR-216a-5p. Besides, miR-216a-5p or BCL2L2 knockdown partly attenuated the inhibitory influences of circ_0011946 silence or miR-216a-5p overexpression on OSCC cell progression. Furthermore, circ_0011946 post-transcriptionally regulated BCL2L2 through sponging miR-216a-5p. Moreover, circ_0011946 knockdown constrained OSCC tumor growth in vivo. Conclusion Circ_0011946 silence repressed OSCC cell proliferation, migration, and invasion, but promoted apoptosis through the regulation of the miR-216a-5p/BCL2L2 axis.

The BCL-2 family of proteins integrates signals that trigger either cell survival or apoptosis. The balance between pro-survival and pro-apoptotic proteins is important for tissue development and homeostasis, while impaired apoptosis contributes to several pathologies and can be a barrier against effective treatment. BCL-w is an anti-apoptotic protein that shares a sequence similarity with BCL-XL, and exhibits a high conformational flexibility. BCL-w level is controlled by a number of signaling pathways, and the repertoire of transcriptional regulators largely depends on the cellular and developmental context. As only a few disease-relevant genetic alterations of BCL2L2 have been identified, increased levels of BCL-w might be a consequence of abnormal activation of signaling cascades involved in the regulation of BCL-w expression. In addition, BCL-w transcript is a target of a plethora of miRNAs. Besides its originally recognized pro-survival function during spermatogenesis, BCL-w has been envisaged in different types of normal and diseased cells as an anti-apoptotic protein. BCL-w contributes to survival of senescent and drug-resistant cells. Its non-apoptotic role in the promotion of cell migration and invasion has also been elucidated. Growing evidence indicates that a high BCL-w level can be therapeutically relevant in neurodegenerative disorders, neuron dysfunctions and after small intestinal resection, whereas BCL-w inhibition can be beneficial for cancer patients. Although several drugs and natural compounds can bi-directionally affect BCL-w level, agents that selectively target BCL-w are not yet available. This review discusses current knowledge on the role of BCL-w in health, non-cancerous diseases and cancer.

Clostridium perfringens beta2 (CPB2) toxin can cause intestinal damage and inflammatory responses in a variety of animals, which seriously endanger the healthy development of animal husbandry. Increasing evidence has demonstrated that microRNAs (miRNAs) can play an important regulatory role in the process of pathogenic infection. In our previous study, we found that miR-204 was highly expressed in the ileum tissues of the susceptible group diarrhea piglets after infection with Clostridium perfringens (C. perfringens) type C. In this study, we found that miR-204 was also up-regulated in different time points after CPB2 toxin treatment. Overexpression of miR-204 promoted apoptosis and inflammatory response of intestinal porcine epithelial cells (IPEC-J2), whereas the opposite results were displayed after transfected with miR-204 inhibitor. Furthermore, the luciferase reporter assays confirmed that BCL2L2 was a direct target gene of miR-204. Interestingly, we found that overexpression BCL2L2 attenuated the apoptosis and inflammatory response of CPB2 toxin induced IPEC-J2 cells. In conclusion, these results find that miR-204 promotes the apoptosis and intensify inflammatory response of CPB2 toxin induced IPEC-J2 cells via targeting BCL2L2. These data provide a valuable reference for the piglets resistance diarrhea at the molecular level.

Recurrent spontaneous abortion (RSA) is a common health problem that affects 1-5% of women in reproductive age. Plenty of studies have indicated that microRNAs (miRNAs) are involved in the occurrence of miscarriage. MiR-93 has a wide range of functions in mammalian tissues and plays an important role in many diseases especially for cancers. However, it remains unknown whether miR-93 is associated with human RSA. In this report, clinical samples revealed that miR-93 expression was significantly elevated in the villi tissues of RSA patients. Upregulation of miR-93 inhibited human trophoblast cells HTR-8/SVneo cell proliferation, migration, and invasiveness, but promoted cell apoptosis in vitro. Conversely, the downregulation of miR-93 reversed these effects. Bcl-2 like protein 2 (BCL2L2), a potential target gene of miR-93, was inversely correlated with miR-93 expression in the villi of clinical samples. Furthermore, the luciferase reporter system demonstrated that miR-93 directly downregulated the expression of BCL2L2 by binding a specific sequence of its 3'-untranslated region (3'UTR). Collectively, these data strongly suggest that miR-93 regulates trophoblast cell proliferation, migration, invasive, and apoptosis by targeting BCL2L2 expression and is involved in the pathogenesis of RSA.

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents. However, the underlying mechanism of osteosarcoma carcinogenesis and progression remains unknown. In the present study, we evaluated the expression profile of miRNAs in osteosarcoma tissues and the adjacent normal tissues. We found that the expression of miR-422a was down-regulated in osteosarcoma tissues and cell lines. In addition, we observed significantly elevated levels of repressive H3K9me3 and H3K27me3 and decreased active H3K4me3 on the promote region of miR-422a in osteosarcoma cells and clinical samples. Furthermore, up-regulation of miR-422a exhibited both in vitro and in vivo anti-tumor effects by inhibiting osteosarcoma cell growth and inducing apoptosis and cell cycle arrest. We also found that miR-422a targeted BCL2L2 and KRAS and negatively regulated their protein expression. Furthermore, restoration of miR-422a and knockdown of BCL2L2 and KRAS promoted apoptosis and induce cell cycle arrest in osteosarcoma cells. Taken together, the present study demonstrates that miR-422a may serve as a tumor suppressor in osteosarcoma via inhibiting BCL2L2 and KRAS translation both in vitro and in vivo. Therefore, miR-422a could be developed as a novel therapeutic target in osteosarcoma.

Aberrant expressions of microRNAs have been reported to be strongly associated with the progression and prognosis of various tumors, including oral squamous cell carcinoma (OSCC). Recent studies on miRNA expression profiling have suggested that microRNA-16 (miR-16) may be dysregulated in OSCC. However, the tumorigenic roles and mechanisms of miR-16 in OSCC are still largely unknown. In this study, we demonstrated that miR-16 was specifically downregulated in both OSCC patients and cancer cell lines. In addition, functional roles of miR-16 in vitro suggested that the miR-16 mimic inhibited cell proliferation and induced apoptosis, whereas miR-16 inhibitor displayed the opposite effects. Luciferase reporter assay and correlation analysis showed that AKT3 and BCL2L2 were directly targeted by miR-16 and were inversely expressed with miR-16 in OSCC. Moreover, restoration of AKT3 and BCL2L2 expression could partially reverse the cell proliferation inhibition and apoptosis induction caused by miR-16. In xenograft nude mice, miR-16 mimics decreased the expression of AKT3 and BCL2L2 and reduced the tumors volumes and weights, whereas the miR-16 inhibitor exhibited adverse effects in the derived xenografts. In conclusion, the findings suggested that miR-16 functions as a tumor suppressor miRNA to inhibit cell proliferation and induce apoptosis in OSCC through decreasing the oncogenes AKT3 and BCL2L2 and that miR-16 could be a potential therapeutic target for OSCC.

Background Non-small-cell lung cancer (NSCLC) is an aggressive neoplasm with a poor survival and novel therapies are urgently needed. The study of deregulated micro- RNAs (dereg-miRs) could constitute a strategy helping to detect specific genes playing a relevant role in the disease. Thus, the oncoproteins encoded by these genes could be exploited as novel therapeutic targets to be inhibited by small molecules, aptamers, or monoclonal antibodies. Methods The present review is focused on candidate genes having convincing biological evidences to be both bona fide targets for dereg-miRs and playing a role in NSCLC progression. These genes were evaluated according to the molecular pathway they belong. Moreover, in the attempt to provide an even broader list of candidate therapeutic targets for NSCLC, the full list of genes was analyzed using the online tool Interactome DB. Results Among the identified targets, some of them belong to p53 or MAP kinase signaling pathways, and others include caspases, MCL1, and BCL2L2 (playing a role in apoptosis), ZEB1, ZEB2, and USP25 (epithelial-to-mesenchymal transition), EZH2, SOX9, and HOXA5 (differentiation), Paxillin, LIMK1 and MTDH (cytoskeleton remodeling), and HDGF (angiogenesis). In addition, other targets, such as TIMP-2, PIM-1, and components of the IGF-signaling pathways were suggested following the interactome analysis. Conclusion Studies on dereg-miRs helped to identify a set of genes whose encoded proteins could constitute candidates for future therapeutic approaches.

BACKGROUND MicroRNA-133b (miR-133b) has been reported to be involved in many diseases, including ovarian cancer and osteosarcoma. Accumulating evidence suggests that miR-133b plays important roles in human disease. In this study, we aimed to investigate the molecular mechanism, including the potential regulator and signaling pathways, of BCL2L2. MATERIAL AND METHODS We first searched the online miRNA database (www.mirdb.org) using the "seed sequence" located within the 3'-UTR of the target gene, and then performed luciferase assay to test the regulatory relationship between miR-133b and BCL2L2. Western blot and real-time PCR were used to determine the expression of BCL2L2 in human samples or cells treated with miRNA mimics or inhibitors. Flow cytometry was conducted to evaluate the apoptosis status of the cells. RESULTS We validated BCL2L2 to be the direct gene using a luciferase reporter assay. We also conducted real-time PCR and Western blot analyses to study the mRNA and protein expression level of BCL2L2 among different groups (control: n=29, cataract: n=33) or cells treated with scramble control, miR-133b mimics, BCL2L2 siRNA, and miR-133b inhibitors, and identified the negative regulatory relationship between miR-133b and BCL2L2. We also conducted experiments to investigate the influence of miR-133b and BCL2L2 on the viability and apoptosis of cells. The results showed that miR-133b positively interfered with the viability of cells, while BCL2L2 negatively interfered with the viability of cells, and that miR-133b inhibited apoptosis while BCL2L2 accelerated apoptosis. CONCLUSIONS BCL2L2 was the virtual target of miR-133b, and we found a negative regulatory relationship between miR-133b and BCL2L2. MiR-133b and BCL2L2 interfered with the viability and apoptosis of cells.

MiRNAs regulate gene expression post-transcriptionally and pre-translationally. Through gene regulation, several miRNAs have been found to play a significant role in various diseases. Each miRNA has multiple targets and is able to have a potent, albeit complex, effect on the cells. Specifically, miRNA-15a has been found to significantly reduce cancer cell survival and aggressiveness through multiple mechanisms across several cancer types. Our research found that miRNA-15a was able to decrease melanoma cell viability in-vitro and in-vivo. We have also found that miRNA-15a caused cell cycle arrest at the G 0 /G 1 phase. Moreover, miRNA-15a was found to decrease the invasiveness of melanoma cells. CDCA4 was also discovered as a novel bona-fide target of miRNA-15a. The following oncogenic mRNAs are verified targets of miRNA-15a: CDCA4, BCL2L2, YAP1, AKT-3, Cyclin E1, and γ-Synuclein. In the future we hope to better understand which miRNAs will be effective in different transcriptome and genome environments. Efforts such as the NIH Center for Cancer Genomics’ ‘The Cancer Genome Atlas,’ ‘Cancer Target and Driver Discovery Network,’ and the ‘Human Cancer Models Initiatives’ among others, will help us characterize the specific tumor environments in which different miRNAs are able to reduce cancer proliferation and aggression. This information will be enhanced by improving the delivery of miRNA by inducing its expression in-situ with dCas9 conjugated to activation domains.

This study determined the changes in microRNA (miRs) expression in mammalian Chinese hamster ovary (CHO) cells undergoing apoptosis induced by exposing the cells to nutrient-depleted media. The apoptosis onset was confirmed by reduced cell viability and Caspase-3/7 activation. Microarray comparison of known mouse and rat miRs in CHO cells exposed to fresh or depleted media revealed up-regulation of the mouse miR-297-669 cluster in CHO cells subjected to depleted media. The mmu-miR-466h was chosen for further analysis as the member of this cluster with the highest overexpression and its up-regulation in depleted media was confirmed with qRT-PCR. Since miRs suppress mRNA translation, we hypothesized that up-regulated mmu-miR-466h inhibits anti-apoptotic genes and induces apoptosis. A combination of bioinformatics and experimental tools was used to predict and verify mmu-miR-466h anti-apoptotic targets. 8708 predicted targets were obtained from miRecords database and narrowed to 38 anti-apoptotic genes with DAVID NCBI annotation tool. Several genes were selected from this anti-apoptotic subset based on nucleotide pairing complimentarity between the mmu-miR-466h seed region and 3' UTR of the target mRNAs. The qRT-PCR analysis revealed reduced mRNA levels of bcl2l2, dad1, birc6, stat5a, and smo genes in CHO cells exposed to depleted media. The inhibition of the mmu-miR-466h increased the expression levels of those genes and resulted in increased cell viability and decreased Caspase-3/7 activation. The up-regulation of mmu-miR-466h in response to nutrients depletion causes the inhibition of several anti-apoptotic genes in unison. This suggests the pro-apoptotic role of mmu-miR-466h and its capability to modulate the apoptotic pathway in mammalian cells.

// Hyun Joo Chung 1, 2 , Young Eun Choi 1 , Eun Sook Kim 1, 2 , Young-Hoon Han 1 , Myung-Jin Park 1, 2 , In Hwa Bae 1, 2 1 Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences, Seoul, Korea 2 Research Center for Radio-Senescence, Korea Institute of Radiological & Medical Sciences, Seoul, Korea Correspondence to: In Hwa Bae, e-mail: ihbae@kirams.re.kr Keywords: miR-29b, BCL2L2, tumorigenicity, stemness, GBM Received: March 24, 2015 Accepted: June 09, 2015 Published: June 19, 2015 ABSTRACT 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.

Increasing evidence has demonstrated that small non-coding microRNAs (miRNAs) play important roles in cancer development and progression. Recent studies have shown that microRNA-335 (miR-335) functions as an oncogene or a tumor suppressor in various human cancer types, but its role in clear cell renal cell carcinoma (ccRCC) remains poorly understood. In our study, we firstly found that the expression level of miR-335 was significantly downregulated in ccRCC tissues versus corresponding non-tumor tissues and the low expression of miR-335 was significantly associated with lymph node metastasis, larger tumor size, and poor T stage. Then, we found that overexpression of miR-335 significantly suppressed the proliferation and invasion of 786-O and CaKi-1 ccRCC cell lines. We subsequently found that miR-335 could interact with the 3′-untranslated regions (3′UTR) of B-cell CLL/lymphoma 2 like 2 (BCL-W or BCL2L2) messenger RNA (mRNA) and repress its expression. In addition, re-expression of BCL-W (without the 3′UTR) could partially abrogate the miR-335-induced 786-O and CaKi-1 ccRCC cell proliferation and invasion inhibition. Furthermore, we found that expression patterns of miR-335 were inversely correlated with those of BCL-W mRNA in ccRCC tissues. Taken together, these results indicate that miR-335 acts as a novel tumor suppressor to regulate ccRCC cell proliferation and invasion through downregulation of BCL-W expression.

MiR-214 has been shown to inhibit cell growth, migration and invasion. Here we demonstrate that ectopic expression of miR-214 reduces cell survival, induces apoptosis and enhances sensitivity to cisplatin through directly inhibiting Bcl2l2 expression in cervical cancer HeLa and C-33A cells. Further analysis reveals that apoptosis induced by miR-214 is correlated with increased expression of Bax, caspase-9, caspase-8 and caspase-3. Moreover, we show that miR-214 is regulated by DNA methylation and histone deacetylation. Taken together, these data suggest that miR-214 might be a candidate target for the development of novel therapeutic strategies to treat cervical cancer.

It is increasingly clear that microRNAs (miRNAs) play an important role in controlling cell survival. However, the functional significance of miRNAs in ischemic brain injury remains poorly understood. In the present study, we assayed the expression levels of miR-29b after ischemic brain injury, and defined the target genes and biological functions of miR-29b. We found that the miR-29b levels were significantly increased in rat brain after transient middle cerebral artery occlusion and neurons after oxygen–glucose deprivation. Moreover, ectopic expression of miR-29b promoted neuronal cell death, whereas its repression decreased cell death. Furthermore, we verified that miR-29b directly targeted and inhibited Bcl2L2 gene expression, and then increased neuronal cell death. Importantly, Bcl2L2 overexpression rescued neuronal cell death induced by miR-29b. These results suggest an important role of miR-29b in regulating neuronal cell death, thus offering a new target for the development of therapeutic agents against ischemic brain injury.

Lung cancer is the most frequent cause of cancer-related death in this country for men and women. MicroRNAs (miRNAs) are a family of small non-coding RNAs (approximately 21–25 nt long) capable of targeting genes for either degradation of mRNA or inhibition of translation. We identified aberrant expression of 41 miRNAs in lung tumor versus uninvolved tissue. MiR-133B had the lowest expression of miRNA in lung tumor tissue (28 fold reduction) compared to adjacent uninvolved tissue. We identified two members of the BCL-2 family of pro-survival molecules (MCL-1 and BCL2L2 (BCLw)) as predicted targets of miR-133B. Selective over-expression of miR-133B in adenocarcinoma (H2009) cell lines resulted in reduced expression of both MCL-1 and BCL2L2. We then confirmed that miR-133B directly targets the 3’UTRs of both MCL-1 and BCL2L2. Lastly, over-expression of miR-133B induced apoptosis following gemcitabine exposure in these tumor cells. To our knowledge, this represents the first observation of decreased expression of miR-133B in lung cancer and that it functionally targets members of the BCL-2 family.

MicroRNAs (miRNAs) decrease the expression of specific target oncogenes or tumor suppressor genes and thereby play crucial roles in tumorigenesis and tumor growth. To date, the potential miRNAs regulating osteosarcoma growth and progression are not fully identified yet. In this study, the miRNA microarray assay and hierarchical clustering analysis were performed in human osteosarcoma samples. In comparison with normal human skeletal muscle, 43 miRNAs were significantly differentially expressed in human osteosarcomas (fold change ≥2 and p≤0.05). Among these miRNAs, miR-133a and miR-133b expression was decreased by 135 folds and 47 folds respectively and the decreased expression was confirmed in both frozen and paraffin-embedded osteosarcoma samples. The miR-133b precursor expression vector was then transfected into osteosarcoma cell lines U2-OS and MG-63, and the stable transfectants were selected by puromycin. We found that stable over-expression of miR-133b in osteosarcoma cell lines U2-OS and MG-63 inhibited cell proliferation, invasion and migration, and induced apoptosis. Further, over-expression of miR-133b decreased the expression of predicted target genes BCL2L2, MCL-1, IGF1R and MET, as well as the expression of phospho-Akt and FAK. This study provides a new insight into miRNAs dysregulation in osteosarcoma, and indicates that miR-133b may play as a tumor suppressor gene in osteosarcoma.

Advanced prostate cancers are known to acquire not only invasive capabilities but also significant resistance to chemotherapy-induced apoptosis. To understand how microRNAs (miRNAs) may contribute to prostate cancer resistance to apoptosis, we compared microRNA expression profiles of a benign prostate cancer cell line WPE1-NA22 and a highly malignant WPE1-NB26 cell line (derived from a common lineage). We found that miR-205 and miR-31 are significantly downregulated in WPE1-NB26 cells, as well as in other cell lines representing advanced-stage prostate cancers. Antiapoptotic genes BCL2L2 (encoding Bcl-w) and E2F6 are identified as the targets of miR-205 and miR-31, respectively. By downregulating Bcl-w and E2F6, miR-205 and miR-31 promote chemotherapeutic agents-induced apoptosis in prostate cancer cells. The promoter region of the miR-205 gene was cloned and was found to be hypermethylated in cell lines derived from advanced prostate cancers, contributing to the downregulation of the gene. Treatment with DNA methylation inhibitor 5-aza-2′-deoxycytidine induced miR-205 expression, downregulated Bcl-w, and sensitized prostate cancer cells to chemotherapy-induced apoptosis. Thus, downregulation of miR-205 and miR-31 has an important role in apoptosis resistance in advanced prostate cancer.