MicroRNA-320a inhibits cell proliferation, migration and invasion by targeting BMI-1 in nasopharyngeal carcinoma

The Crucial Roles of Bmi-1 in Cancer: Implications in Pathogenesis, Metastasis, Drug Resistance, and Targeted Therapies

B-cell-specific Moloney murine leukemia virus integration region 1 (Bmi-1, also known as RNF51 or PCGF4) is one of the important members of the PcG gene family, and is involved in regulating cell proliferation, differentiation and senescence, and maintaining the self-renewal of stem cells. Many studies in recent years have emphasized the role of Bmi-1 in the occurrence and development of tumors. In fact, Bmi-1 has multiple functions in cancer biology and is closely related to many classical molecules, including Akt, c-MYC, Pten, etc. This review summarizes the regulatory mechanisms of Bmi-1 in multiple pathways, and the interaction of Bmi-1 with noncoding RNAs. In particular, we focus on the pathological processes of Bmi-1 in cancer, and explore the clinical relevance of Bmi-1 in cancer biomarkers and prognosis, as well as its implications for chemoresistance and radioresistance. In conclusion, we summarize the role of Bmi-1 in tumor progression, reveal the pathophysiological process and molecular mechanism of Bmi-1 in tumors, and provide useful information for tumor diagnosis, treatment, and prognosis.

Extracellular vesicle-derived miR-320a targets ZC3H12B to inhibit tumorigenesis, invasion, and angiogenesis in ovarian cancer

Extracellular vesicles (EVs) play crucial roles in intercellular communication. miRNAs derived from EVs emerge as promising diagnostic indicators and therapeutic targets in a variety of malignancies. Tremendous studies have revealed the function of miRNAs derived from EVs in tumorigenesis, metastasis and other aspects. The mechanism of action of EV-derived miRNAs, however, in ovarian cancer remains largely unknown. In this study, EVs were enriched from the ovarian cancer cell lines. EVs as a whole could promote cell proliferation, invasion and new vasculature formation. However, the down-regulated EV-derived miR-320a was demonstrated to potentially suppress tumorigenesis, metastasis and angiogenesis. Moreover, EV-derived miR-320a has been proved to directly regulate a previously unknown target, ZC3H12B. An unreported role of ZC3H12B in promoting ovarian cancer cell proliferation has been elucidated and miR-320a could mediate the expression of ZC3H12B, thereby inhibiting the downstream response. As for the practical clinic values, lower expression of EV-derived miR-320a correlates with shorter survival period, indicating that EV-derived miR-320a may also serve as a prognostic biomarker in ovarian cancer. This research provides new insight into the molecular mechanism of EV-derived miR-320a in ovarian cancer and may provide new therapeutic and prognostic strategies for ovarian cancer treatment.

MicroRNA-320a-containing exosomes from human umbilical cord mesenchymal stem cells curtail proliferation and metastasis in lung cancer by binding to SOX4

Exosomes from human umbilical cord mesenchymal stem cells (HUCMSCs) containing microRNAs (miRNAs) have been underscored as possible therapeutic options for cancers. Hence, our goal here was to investigate the relevance of miR-320a-containing exosomes from HUCMSCs to lung cancer. First, H1299 and H460 cells were co-cultured with the exosomes overexpressing miR-320a from HUCMSCs. The data displayed that HUCMSCs-secreted exosomes expressing miR-320a exerted anti-tumor effects in vitro and in vivo. Online analysis available at TargetScan database revealed that miR-320a bound to sex-determining region Y-box 4 (SOX4), and the luciferase reporter gene assay clarified this targeting relationship. Next, a β-catenin-specific agonist WAY-262611 was delivered into the H1299 and H460 cells to assess the effects of the Wnt/β-catenin pathway on lung cancer cellular processes. The results demonstrated that WAY-262611 potentiated lung cancer cell viability, invasion, and migration, but inhibited cell apoptosis. Altogether, exosomes carrying miR-320a from HUCMSCs might suppress lung cancer cell growth via the SOX4/Wnt/β-catenin axis, which highpoints the potency of exosomes expressing miR-320a as a possible therapeutic option for lung cancer treatment.

MicroRNA 320, an Anti-Oncogene Target miRNA for Cancer Therapy

MicroRNAs are a set of highly conserved non-coding RNAs that control gene expression at the post-transcriptional/translational levels by binding to the 3′-UTR of diverse target genes. Increasing evidence indicates that miRNAs not only play a vital role in many biological processes, but they are also frequently deregulated in pathological conditions, including cancer. The miR-320 family is one of many tumor suppressor families and is composed of five members, which has been demonstrated to be related to the repression of epithelial-mesenchymal transition (EMT) inhibition, cell proliferation, and apoptosis. Moreover, this family has been shown to regulate drug resistance, and act as a potential biomarker for the diagnosis, prognosis, and prediction of cancer. In this review, we summarized recent research with reference to the tumor suppressor function of miR-320 and the regulation mechanisms of miR-320 expression. The collected evidence shown here supports that miR-320 may act as a novel biomarker for cancer prognosis and therapeutic response to cancer treatment.

Regulation of gene transcription of B lymphoma Mo-MLV insertion region 1 homolog (Review)

B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is a core protein component of the polycomb repressive complex 1 that inhibits cell senescence and maintains the self-renewal ability of stem cells via downregulation of p16Ink4a and p19Arf expression. Bmi-1 serves an important role in hematopoietic stem cell maintenance and neurodevelopment during embryonic development, and it has been shown to enhance tumorigenesis by promoting cancer stem cell self-renewal and epithelial to mesenchymal transition. Emerging evidence suggests that Bmi-1 overexpression is closely related to the development and progression of various types of cancer, and that downregulation of Bmi-1 expression can inhibit the proliferation, invasion and metastasis of cancer cells. It is therefore important to elucidate the mechanisms underlying the regulation of Bmi-1 expression both under normal growth conditions and in malignant tissues. In the present review, the current body of knowledge pertaining to the transcriptional and post-transcriptional regulation of the BMI-1 gene is discussed, and the potential mechanisms by which Bmi-1 is dysregulated in various types of cancer are highlighted. Bmi-1 expression is primarily controlled via transcriptional regulation, and is regulated by the transcription https://www.ushuaia.pl/hyphen/?ln=en factors of the Myc family, including Myb, Twist1, SALL4 and E2F-1. Post-transcriptionally, regulation of Bmi-1 expression is inhibited by several microRNAs and certain small-molecule drugs. Thus, regulatory transcriptional factors are potential therapeutic targets to reduce Bmi-1 expression in cancer cells. Thus, the present review provides an up-to-date review on the regulation of BMI-1 gene expression at the transcriptional and post-transcriptional level.

Circulating miR-320a Acts as a Tumor Suppressor and Prognostic Factor in Non-small Cell Lung Cancer

Dysregulated expression profiles of microRNAs (miRNAs) have been observed in several types of cancer, including non-small cell lung cancer (NSCLC); however, the diagnostic and prognostic potential of circulating miRNAs in NSCLC remains largely undefined. Here we found that circulating miR-320a was significantly down-regulated (~5.87-fold; p < 0.0001) in NSCLC patients (n = 80) compared to matched control plasma samples from healthy subjects (n = 80). Kaplan-Meier survival analysis revealed that NSCLC patients with lower levels of circulating miR-320a had overall poorer prognosis and survival rates compared to patients with higher levels (p < 0.0001). Moreover, the diagnostic and prognostic potential of miR-320a correlated with clinicopathological characteristics such as tumor size, tumor node metastasis (TNM) stage, and lymph node metastasis. Functionally, depletion of miR-320a in human A549 lung adenocarcinoma cells induced their metastatic potential and reduced apoptosis, which was reversed by exogenous re-expression of miR-320a mimics, indicating that miR-320a has a tumor-suppressive role in NSCLC. These results were further supported by high levels of epithelial-mesenchymal transition (EMT) marker proteins (e.g., Beta-catenin, MMP9, and E-cadherin) in lung cancer cells and tissues via immunoblot and immunohistochemistry experiments. Moreover, through bioinformatics and dual-luciferase reporter assays, we demonstrated that AKT3 was a direct target of miR-320a. In addition, AKT3-associated PI3K/AKT/mTOR protein-signaling pathways were elevated with down-regulated miR-320a levels in NSCLC. These composite data indicate that circulating miR-320a may function as a tumor-suppressor miRNA with potential as a prognostic marker for NSCLC patients.

Decreased serum exosomal miR-320a expression is an unfavorable prognostic factor in patients with hepatocellular carcinoma

Objective

Circulating microRNAs (miRNAs) have promising potential as diagnostic or prognostic biomarkers for hepatocellular carcinoma (HCC). This study aimed to analyze the clinical significance of serum exosomal miR-320a expression in patients with HCC.

Methods

A total of 104 patients with HCC, 55 patients with chronic liver disease (CLD), and 50 healthy volunteers were enrolled. Serum exosomal miR-320a levels were measured by quantitative reverse-transcriptase polymerase chain reaction and compared among the groups. The relationships between exosomal miR-320a levels and clinicopathological factors in patients with HCC were also analyzed.

Results

Serum exosomal miR-320a levels were significantly lower in patients with HCC compared with patients with CLD and healthy controls. Receiver-operating characteristic curve analysis showed that serum exosomal miR-320a had good diagnostic value for distinguishing between HCC subjects and normal controls. Serum exosomal miR-320a levels were significantly elevated 1 month after surgery in patients with HCC. Moreover, serum exosomal miR-320a downregulation was strongly associated with positive lymph node metastasis, positive vein invasion, advanced TNM stage, and shorter survival. Serum exosomal miR-320a was confirmed as an independent prognostic marker for HCC.

Conclusions

Collectively, these results indicate that serum exosomal miR-320a might be a potential biomarker for the detection and prognosis of HCC.

Internal Ribosome Entry Sites Mediate Cap-Independent Translation of Bmi1 in Nasopharyngeal Carcinoma

Bmi1 is overexpressed in multiple human cancers. We previously reported the oncogenic function and the transcription regulation mechanisms of Bmi1 in nasopharyngeal carcinoma (NPC). In this study, we observed that the mRNA and the protein levels of Bmi1 were strictly inconsistent in NPC cell lines and cancer tissues. The inhibitors of proteasome and lysosome could not enhance the protein level of Bmi1, indicating that Bmi1 may be post-transcriptionally regulated. The IRESite analysis showed that there were two potential internal ribosome entry sites (IRESs) in the 5'-untranslated region (5'-UTR) of Bmi1. The luciferase assay demonstrated that the 5'-UTR of Bmi1 has IRES activity, which may mediate cap-independent translation. The IRES activity of the Bmi1 5'-UTR was significantly reduced after the mutation of the two IRES elements. Taken together, these results suggested that the IRES elements mediating translation is a novel post-transcriptional regulation mechanism of Bmi1.

High-quality human preimplantation embryos stimulate endometrial stromal cell migration via secretion of microRNA hsa-miR-320a

STUDY QUESTION

How do high-quality human preimplantation embryos influence the endometrium to promote their own implantation?

SUMMARY ANSWER

High-quality human preimplantation embryos secrete a specific microRNA (miRNA), hsa-miR-320a, which promotes migration of human endometrial stromal cells (hESCs).

WHAT IS KNOWN ALREADY

We have previously shown that high-quality human preimplantation embryos excrete unknown factors that influence migration of hESCs.

STUDY DESIGN, SIZE, DURATION

Embryo excreted miRNAs, specifically those excreted by high-quality embryos, were identified and their effect on hESCs was determined by measuring the migration capacity and gene expression patterns of primary isolated hESCs.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Embryo conditioned medium (ECM) from routine ICSI procedures was used to identify embryo excreted miRNAs. miRNome analyses were performed on ECM from individually cultured embryos with high morphological quality, with low morphological quality or empty control medium. MiRNA mimics and inhibitors were then used to further study the effect of miRNAs of interest on migration and gene expression of hESCs. Migration assays were performed using hESCs that were obtained from endometrial biopsies performed on hysterectomy specimens from women that received surgery for spotting due to a niche in a cesarean section scar.

MAIN RESULTS AND THE ROLE OF CHANCE

By using miRNA mimics and inhibitors, we showed that hsa-miR-320a alone can stimulate migration of decidualized hESCs, accurately resembling the response typically triggered only by high-quality embryos. Transcriptome analysis further demonstrated that this effect is very likely mediated via altered expression of genes involved in cell adhesion and cytoskeleton organization.

LIMITATIONS, REASONS FOR CAUTION

The effect of hsa-miR-320a on hESCs was measured in vitro. Further studies on the in vivo effect of hsa-miR-320a are warranted.

WIDER IMPLICATIONS OF THE FINDINGS

Implantation failure is one of the major success limiting factors in human reproduction. By secreting hsa-miR-320a, high-quality human preimplantation embryos directly influence hESCs, most likely to prime the endometrium at the implantation site for successful implantation. Together, our results indicate that hsa-miR-320a may be a promising target to further increase success rates in assisted reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Amsterdam University Medical Centers and the Amsterdam Reproduction & Development Research Institute. R.P.B., G.H. and S.M. have a patent on the use of hsa-miR-320a in assisted reproduction treatments pending.

TRIAL REGISTRATION NUMBER

N/A.

Exosomal MicroRNA-320a Derived From Mesenchymal Stem Cells Regulates Rheumatoid Arthritis Fibroblast-Like Synoviocyte Activation by Suppressing CXCL9 Expression

Rheumatoid arthritis (RA), a chronic systemic inflammatory disease, is a primary cause of disability worldwide. The involvement of fibroblast-like synoviocytes (FLSs) in the regulation of the pathogenesis of RA has been highlighted. Mesenchymal stem cells (MSCs) are important candidates for cell-based treatment in many inflammatory autoimmune diseases. Herein, we identify whether MSC-derived exosomes loaded with microRNA-320a (miR-320a) regulate RA-FLSs. Synovial tissues from 22 patients with RA and 9 patients with osteoarthritis were collected. RA-FLSs were obtained from patients with RA, and their functions were evaluated by determining levels of interleukin-1β (IL-1β), IL-6, and IL-8 and by transwell migration and invasion assays. Dual luciferase reporter gene assays were employed to identify interaction between miR-320a and CXC chemokine ligand 9 (CXCL9). A co-culture system of MSC-derived exosomes and RA-FLSs were performed. The collagen-induced arthritis (CIA) mouse models with arthritis and bone damage were developed. Our results revealed the existence of reciprocal expression of miR-320a and CXCL9 in the synovial tissues obtained from patients with RA. CXCL9 knockdown or miR-320a upregulation suppressed the activation, migration, and invasion of RA-FLSs. CXCL9 was confirmed to be a target of miR-320a, and CXCL9 overexpression restored RA-FLS function in the presence of miR-320a. MSC-derived exosomes containing miR-320a mimic significantly suppressed RA-FLS activation, migration, and invasion in vitro and attenuated arthritis and bone damage in mice with CIA in vivo. Our study uncovers that MSC-derived exosomes participate in the intercellular transfer of miR-320a and subsequently inhibit the progression of RA. These results provide a novel potential therapeutic approach for RA treatment by increasing miR-320a in exosomes.

B lymphoma Moloney murine leukemia virus insertion region 1: An oncogenic mediator in prostate cancer

B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1), a core member of polycomb repressive complex 1 (PRC1), has been intensely investigated in the field of cancer epigenetics for decades. Widely known as a critical regulator in cellular physiology, BMI1 is essential in self-renewal and differentiation in different lineages of stem cells. BMI1 also plays a significant role in cancer etiology for its involvement in pathological progress such as epithelial–mesenchymal transition (EMT) and cancer stem cell maintenance, propagation, and differentiation. Importantly, overexpression of BMI1 is predictive for drug resistance, tumor recurrence, and eventual therapy failure of various cancer subtypes, which renders the pharmacological targeting at BMI1 as a novel and promising therapeutic approach. The study on prostate cancer, a prevalent hormone-related cancer among men, has promoted enormous research advancements in cancer genetics and epigenetics. This review summarizes the role of BMI1 as an oncogenic and epigenetic regulator in tumor initiation, progression, and relapse of prostate cancer.

MicroRNA-498 inhibits the proliferation, migration and invasion of gastric cancer through targeting BMI-1 and suppressing AKT pathway

Recently, microRNA-498 (miR-498) plays important effect in human cancers. Nonetheless, the role of miR-498 is still unclear in gastric cancer (GC). Therefore, this study was designed to investigate the function of miR-498 in GC tissues and cell lines (SGC-7901, BGC-823, MGC-803). The expressions of miR-498 and BMI-1 were examined in GC tissues via the RT-qPCR assay. The function of miR-498 was investigated through MTT and transwell assays. The relationship between miR-498 and BMI-1 was testified by dual luciferase assay. The protein expression of EMT markers, AKT pathway markers and BMI-1 was measured through western blot. The expression of miR-498 was decreased in GC tissues which predicted poor prognosis of GC patients. Moreover, functional analyses show that the overexpression of miR-498 inhibited the progression of GC. Furthermore, BMI-1 was a direct target of miR-498 which was upregulated in GC. Especially, the upregulation of BMI-1 recovered the suppressive effect of miR-498 in GC. In addition, miR-498 inhibited the metastasis and proliferation of GC cells through blocking EMT and AKT pathway. MiR-498, by targeting BMI-1, presents a plethora of tumor suppressor activities in GC cells.

Downregulation of long non-coding RNA NR2F2-AS1 inhibits proliferation and induces apoptosis of nasopharyngeal carcinoma cells by upregulating the expression of PTEN

The novel long non-coding RNA NR2F2-AS1 has been characterized as an oncogene in lung cancer. The present study aimed to investigate the role of NR2F2-AS1 in nasopharyngeal carcinoma (NPC). The results demonstrated that expression of NR2F2-AS1 and phosphatase and tensin homolog (PTEN) were negatively associated with each other in NPC tissues. Furthermore, upregulated NR2F2-AS1 expression levels and downregulated PTEN expression levels in NPC tissues predicted less favorable survival outcomes in patients with NPC. Transfection of NPC cells with NR2F2-AS1 small interfering RNA resulted in increased expression of PTEN. In addition, NR2F2-AS1 silencing and PTEN overexpression resulted in decreased proliferation and an increase in the apoptotic rate of NPC cells. In conclusion, NR2F2-AS1 downregulation decreased proliferation and increased apoptosis of NPC cells via upregulation of PTEN.

MicroRNA-320a suppresses tumor progression by targeting PBX3 in gastric cancer and is downregulated by DNA methylation

BACKGROUND

Ectopic expression of miRNAs promotes tumor development and progression. miRNA (miR)-320a is downregulated in many cancers, including gastric cancer (GC). However, the mechanism underlying its downregulation and the role of miR-320a in GC are unknown.

AIM

To determine expression and biological functions of miR-320a in GC and investigate the underlying molecular mechanisms.

METHODS

Quantitative real-time polymerase chain reaction (PCR) was used to determine expression of miR-320a in GC cell lines and tissues. TargetScanHuman7.1, miRDB, and microRNA.org were used to predict the possible targets of miR-320a, and a dual luciferase assay was used to confirm the findings. Western blotting was used to detect the protein levels of pre-B-cell leukemia homeobox 3 (PBX3) in GC cells and tissue samples. Cell Counting Kit-8 proliferation, Transwell, wound healing, and apoptosis assays were performed to analyze the biological functions of miR-320a in GC cells. Methylation-specific PCR was used to analyze the methylation level of the miR-320a promoter CpG islands. 5-Aza-2’-deoxycytidine (5-Aza-CdR) and trichostatin A (TSA) were used to treat GC cells.

RESULTS

miR-320a expression was lower in GC cell lines and tissues than in the normal gastric mucosa cell line GES-1 and matched adjacent normal tissues. miR-320a overexpression suppressed GC cell proliferation, invasion and migration, and induced apoptosis. PBX3 was a target of miR-320a in GC. The methylation level of the miR-320a promoter CpG islands was elevated and this was partly reversed by 5-Aza-CdR and TSA.

CONCLUSION

miR-320a acts as a tumor suppressor and inhibits malignant behavior of GC cells, partly by targeting PBX3. DNA methylation is an important mechanism associated with low expression of miR-320a.

Long noncoding RNA SMAD5-AS1 acts as a microRNA-106a-5p sponge to promote epithelial mesenchymal transition in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial cancer of the head and neck with high prevalence in southern China, which is accompanied by notable invasiveness and metastasis. Long noncoding RNAs (lncRNAs) participate in the progression of various cancers including NPC. Microarray-based analysis identified highly expressed lncRNA mothers against decapentaplegic homolog 5 (SMAD5)-antisense RNA 1 (AS1) related to NPC. Interestingly, it is found that SMAD5-AS1 competitively bound to microRNA (miR)-106a-5p to regulate SMAD5. Herein, the study aimed to clarify the role of SMAD5-AS1/miR-106a-5p/SMAD5 axis in the process of epithelial mesenchymal transition (EMT) in NPC. SMAD5-AS1 was highly expressed and miR-106a-5p was poorly expressed in NPC tissues and cell lines. The NPC cells were treated with a series of small interfering RNAs, mimics, or inhibitors to explore the effects of SMAD5-AS1, SMAD5, and miR-106a-5p on EMT, cell proliferation, migration, and invasion in NPC. Of note, SMAD5-AS1 silencing or miR-106a-5p overexpression reduced expression of N-cadherin, matrix metallopeptidase 9, Snail, and Vimentin while elevating E-cadherin expression, thus inhibiting EMT, cell proliferation, migration, and invasion in NPC by down-regulation of SMAD5. Moreover, SMAD5 silencing could reduce the ability of EMT induced by SMAD5-AS1 up-regulation. SMAD5-AS1 silencing or miR-106a-5p elevation inhibited tumorigenesis in nude mice. Taken together, SMAD5-AS1 silencing suppressed EMT, cell proliferation, migration, and invasion in NPC by elevating miR-106a-5p to down-regulate SMAD5, which provided a novel therapeutic target for NPC treatment.-Zheng, Y.-J., Zhao, J.-Y., Liang, T.-S., Wang, P., Wang, J., Yang, D.-K., Liu, Z.-S. Long noncoding RNA SMAD5-AS1 acts as a microRNA-106a-5p sponge to promote epithelial mesenchymal transition in nasopharyngeal carcinoma.

Upregulation of Insulin-Like Growth Factor-1 Receptor (IGF-1R) Reverses the Inhibitory Effect of Let-7g-5p on Migration and Invasion of Nasopharyngeal Carcinoma

Background

Let-7 microRNAs (miRNAs) have the effects of inhibiting tumor growth and metastasis, however, the research in nasopharyngeal carcinoma (NPC) is limited. This study focused on the effects of Let-7 on NPC migration and invasion and the mechanism of action.

Material/Methods

Plasmid transfection was used to upregulate the expression levels of Let-7g-5p and insulin-like growth factor-1 receptor (IGF-1R). Cell counting kit-8 (CCK-8) assay was applied to test the cell viability. Scratch assay and Transwell assay were performed to detect the migration and invasion abilities. Bioinformatics prediction and luciferase reporter assay were used to determine and verify the downstream target genes for Let-7g-5p. Protein and mRNA were detected by western blot and real-time quantitative polymerase chain reaction (RT-qPCR), respectively.

Results

Let-7g-5p was under-expressed in human NPC cells. Overexpression of Let-7g-5p could inhibit cell viability and inhibit the migration and invasion of SUNE1 cells. The dual-luciferase reporter assay showed that IGF-1R was a direct target gene of Let-7g-5p, which was directly regulated IGF-1R expression by 3′UTR. Let-7g-5p overexpression could inhibit the expression of IGF-1R gene, and upregulation of IGF-1R gene expression reversed the inhibitory effect of Let-7g-5p on cell viability and epithelial-mesenchymal transition processes.

Conclusions

Let-7g-5p is lowly expressed in NPC and it was the first to discover that IGF-1R was a target gene of let-7g-5p in NPC. Upregulation of IGF-1R reversed the inhibitory effect of Let-7g-5p on epithelial-mesenchymal transition.

CUL4B regulates cancer stem-like traits of prostate cancer cells by targeting BMI1 via miR200b/c

BACKGROUND

Cancer stem-like traits contribute to prostate cancer (PCa) progression and metastasis. Cullin 4B (CUL4B) is a member of the ubiquitin E3 ligase family and overexpressed in several solid malignancies including PCa. CUL4B has been suggested to be an oncogene through epigenetic repression of tumor suppressors. However, the link between CUL4B expression and cancer stem-like phenotype remains unclear.

METHODS

Western blot analysis, sphere formation, and colony formation assays were used to examine the effect of CUL4B on cancer stem-like traits in PCa cells. Mechanically, bioinformatic analysis was utilized to evaluate whether BMI1 was a target of CUL4B. Moreover, real-time polymerase chain reaction, chromatin immunoprecipitation, and luciferase reporter assays were performed to identify microRNAs regulated by CUL4B. Finally, Western blot assay was used to validate the regulation of CUL4B, miR200b, and miR200c (miR200b/c) on the stem-like characteristics of PCa cells.

RESULTS

CUL4B promotes PCa pluripotency-associated markers expression, sphere formation, and anchorage-independent growth ability in vitro. Mechanically, CUL4B upregulates BMI1 expression via epigenetically repressing miR200b/c expression. In addition, miR200b/c could partially reverse CUL4B-induced BMI1 and pluripotency-associated marker expression.

CONCLUSIONS

Our study revealed that CUL4B regulates cancer stem-like traits of prostate cancer cells by targeting BMI1 via miR200b/c, which might give novel insight into how CUL4B promotes PCa progression through regulating cancer stem-like traits.

miR-143 inhibits proliferation and metastasis of nasopharyngeal carcinoma cells via targeting FMNL1 based on clinical and radiologic findings

Mounting evidence has reported that microRNA-143 (miR-143) is involved in the development of multiple cancers. To investigate the underlying mechanisms of miR-143 regulating proliferation and metastasis in nasopharyngeal carcinoma (NPC) cells, we evaluated the levels of miR-143 and formin-like protein 1 (FMNL1) in NPC tissues. The results of qRT-PCR and Western blot analysis showed that the expression of miR-143 was decreased, while FMNL1 was increased in NPC tissues. The expression of miR-143 was significantly elevated in NPC cells compared with that of human nasopharyngeal epithelial cells. The results of MiRcode prediction, dual-luciferase reporter, and Western blot analysis assays indicated that miR-143 negatively regulated the expression of FMNL1 (r²  = 0.4365P = 0.0001). Overexperssion of miR-143 or FMNL1 knockdown inhibited cell proliferation, migration, and invasion in NPC cells (P < 0.05). Ectopic expression of FMNL1 undermined the inhibition effect of miR-143 on proliferation, migration, and invasion in NPC cells. The findings of this study revealed that miR-143 functioned as a tumor suppressor and inhibited the NPC progression by targeting FMNL1.

Knockdown of serpin peptidase inhibitor clade C member 1 inhibits the growth of nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a type of cancer originating in the nasopharynx. There are no NPC‑specific treatments available at present. Serpin peptidase inhibitor clade C member 1 (SERPINC1) serves roles in anticoagulation and anti‑inflammation. The aim of the present study was to investigate the role of SERPINC1 in the proliferation and apoptosis of NPC cells. Tumor and adjacent healthy tissue samples were collected from patients with NPC. Additionally, the SERPINC1 gene was silenced in the HNE3 cell line using short interfering RNA targeted against SERPINC1 (SERPINC1‑siRNA). Cell viability was determined via a Cell Counting Kit‑8 assay; furthermore, proliferation and apoptosis were investigated via flow cytometry. Western blotting and reverse transcription‑quantitative polymerase chain reaction analysis were performed to determine the expression levels of protein and mRNA. It was revealed that the expression levels of SERPINC1 mRNA and protein were increased in NPC tumor tissues compared with in adjacent healthy tissues. The expression of SERPINC1 mRNA and protein in HNE3 cells decreased following SERPINC1‑siRNA transfection. Furthermore, knockdown of SERPINC1 promoted apoptosis and inhibited proliferation. It was also demonstrated that silencing SERPINC1 upregulated the expression of B‑cell lymphoma-2 (Bcl‑2)‑associated X protein and p53 mRNA and protein, and downregulated that of Bcl‑2, survivin and cyclin D1. Downregulation of SERPINC1 reduced the phosphorylation of phosphatidylinositol 3‑kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR). Thus, SERPINC1 knockdown may promote the apoptosis of HNE3 cells and inhibit proliferation via the suppression of the PI3K/Akt/mTOR signaling pathway.

SUN2: A potential therapeutic target in cancer

The incidence of cancer is increasing at an alarming rate despite recent advances in prevention strategies, diagnostics and therapeutics for various types of cancer. The identification of novel biomarkers to aid in prognosis and treatment for cancer is urgently required. Uncontrolled proliferation and dysregulated apoptosis are characteristics exhibited by cancer cells in the initiation of various types of cancer. Notably, aberrant expression of crucial oncogenes or cancer suppressors is a defining event in cancer occurrence. Research has demonstrated that SAD1/UNC84 domain protein-2 (SUN2) serves a suppressive role in breast cancer, atypical teratoid/rhabdoid tumors and lung cancer progression. Furthermore, SUN2 inhibits cancer cell proliferation, migration and promotes apoptosis. Recent reports have also shown that SUN2 serves prominent roles in resistance to the excessive DNA damage that destabilizes the genome and promotes cancer development, and these functions of SUN2 are critical for evading initiation of cancer. Additionally, increasing evidence has demonstrated that SUN2 is involved in maintaining cell nuclear structure and appears to be a central component for organizing the natural nuclear architecture in cancer cells. The focus of the present review is to provide an overview on the pharmacological functions of SUN2 in cancers. These findings suggest that SUN2 may serve as a promising therapeutic target and novel predictive marker in various types of cancer.

MicroRNA‑320a suppresses tumour cell proliferation and invasion of renal cancer cells by targeting FoxM1

An increasing body of evidence has indicated that microRNAs (miRNAs/miRs) may play an important role in tumourigenesis and tumour progression. Recent studies have demonstrated that miR‑320a is aberrantly expressed in a variety of different types of human cancer. The results of the present study confirmed that the expression of miR‑320a was decreased in clinical specimens and cell lines. Expression of miR‑320a inhibited the growth and invasive ability of ACHN and Caki‑1 cells. Bioinformatics analysis and a luciferase reporter assay demonstrated that forkhead box protein M1 (FoxM1) was directly regulated by miR‑320a. Rescue experiments in vitro revealed that the upregulation of FoxM1 antagonized the miR‑320a‑mediated malignant phenotype in renal cancer. Furthermore, experiments employing a xenograft mouse model revealed that the upregulation of miR‑320a inhibited the proliferation of renal cancer cells in nude mice when FoxM1 protein expression was reduced. Collectively, the present study demonstrated a novel molecular interaction regulated by miR‑320a, which may provide a novel insight into the treatments for renal cancer.

Specific miRNA expression profile in the blood serum of cardiac myxoma patients

The profile of differentially expressed microRNAs (miRNAs) in the serum of patients with cardiac myxoma (CM) (n=30) and healthy people (n=30) was studied using miRNA microarray analysis. The expression of the candidate miRNAs was validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in the serum of 30 CM patients and 30 healthy control individuals. TargetScan, PicTar and miRanda were used to predict the possible target gene of miR-320a. The Gene Ontology database and Kyoto Encyclopedia of Genes and Genomes database were used to enrich the functions and signaling pathways of the target genes, respectively. The results showed that 4 differentially expressed miRNAs were identified, the expression levels of miR-320a and miR-1249-5p were upregulated, and those of miR-634 and miR-6870-3p were downregulated in CM patients (P<0.05). The expression levels of miR-320a and miR-634 selected for verification by RT-qPCR were in high concordance with the results of microarray analysis. Through bioinformatics, we identified 487 target genes predicted from miR-320a, that were mostly enriched in the bone morphogenetic protein signaling pathway, nicotinamide adenine dinucleotide pathway and de novo ceramide biosynthetic pathway. In our study, we reported for the first time the circulating miRNA profile of CM patients and suggested that miR-320a may participate in CM development through the ceramide signaling pathway.

USP14 de-ubiquitinates vimentin and miR-320a modulates USP14 and vimentin to contribute to malignancy in gastric cancer cells

Vimentin plays important roles in the epithelial-to-mesenchymal transition (EMT). In this study, we found that vimentin was highly expressed in human gastric cancer (GC) tissues and cell lines and significantly promoted cell growth, migration and invasion. Ubiquitin-specific protease 14 (USP14) interacted with the vimentin protein, which led to its de-ubiquitination. miR-320a was found to bind to the 3′UTR of both vimentin and USP14 transcripts and downregulate the expression of both proteins. The downregulation of miR-320a upregulates vimentin expression by directly binding to the 3′UTR of vimentin to derepress expression and indirectly by augmenting USP14 to increase vimentin stability in GC cells. Taken together, these results provide new insight into malignancy in gastric cancers.

MicroRNA-320a inhibits breast cancer metastasis by targeting metadherin

Dysregulated microRNAs play important pathological roles in carcinogenesis that are yet to be fully elucidated. This study was performed to investigate the biological functions of microRNA-320a (miR-320a) in breast cancer and the underlying mechanisms. Function analyses for cell proliferation, cell cycle, and cell invasion/migration, were conducted after miR-320a silencing and overexpression. The specific target genes of miR-320a were predicted by TargetScan algorithm and then determined by dual luciferase reporter assay and rescue experiment. The relationship between miR-320a and its target genes was explored in human breast cancer tissues. We found that miR-320a overexpression could inhibit breast cancer invasion and migration abilities in vitro, while miR-320a silencing could enhance that. In addition, miR-320a could suppress activity of 3′-untranslated region luciferase of metadherin (MTDH), a potent oncogene. The rescue experiment revealed that MTDH was a functional target of miR-320a. Moreover, we found that MTDH was negatively correlated with miR-320a expression, and it was related to clinical outcomes of breast cancer. Further xenograft experiment also showed that miR-320a could inhibit breast cancer metastasis in vivo. Our findings clearly demonstrate that miR-320a suppresses breast cancer metastasis by directly inhibiting MTDH expression. The present study provides a new insight into anti-oncogenic roles of miR-320a and suggests that miR-320a/MTDH pathway is a putative therapeutic target in breast cancer.

Nanocurcumin restores aberrant miRNA expression profile in multiple sclerosis, randomized, double-blind, placebo-controlled trial

In the current study, we aimed to identify nanocurcumin effects on microRNAs (miRNAs) in the peripheral blood of patients with relapsing-remitting multiple sclerosis (RRMS). We intended to investigate the expression pattern of these miRNAs in experimental settings in vivo. The expression levels of the selected 27 miRNAs known to be involved in the regulation of immune responses were analyzed in 50 RRMS patients and 35 healthy controls. The miRNA expression profiles were investigated by quantitative PCR (qPCR) at baseline and after 6 months of nanocurcumin therapy. Our data revealed that the expression of a number of microRNAs including miR-16, miR-17-92, miR-27, miR-29b, miR-126, miR-128, miR-132, miR-155, miR-326, miR-550, miR-15a, miR-19b, miR-106b, miR-320a, miR-363, miR-31, miR-150, and miR-340 is regulated by nanocurcumin. The results of the current work indicate that nanocurcumin is able to restore the expression pattern of dysregulated miRNAs in MS patients. We discovered that some miRNAs are deregulated in untreated patients compared with healthy controls and nanocurcumin-treated patients. This is a new finding that might represent the potential contribution of these miRNAs to MS pathogenesis. Taken together, these data provide novel insights into miRNA-dependent regulation of the function of B and T cells in MS disease and enrich our understanding of the effects mediated by a therapeutic approach that targets B and T cells.

MiRNA-320a inhibits trophoblast cell invasion by targeting estrogen-related receptor-gamma

AIM

MicroRNAs (miRs) play an essential role in the modulation of trophoblast function. We explored miR-320a expression in the human placenta. In addition, we report the promising effect and target functional loop of miR-320a in trophoblasts.

METHODS

MiR-320a expression was investigated in both pre-eclamptic and healthy placenta tissues by quantitative real time-polymerase chain reaction to determine how miR-320a affected invasion, proliferation and migration in trophoblasts. A lipopolysaccharide (LPS) model was established in trophoblasts to reveal how LPS supplementation stimulated miR-320a expression. Western blot was applied to measure protein expression, which was involved in pathways modulated by miR-320a in pre-eclamptic placentas.

RESULTS

MiR-320a expression was enhanced in the placental specimens of pre-eclamptic patients. Excessive miR-320a expression remarkably suppressed trophoblast invasion but did not affect migration or proliferation. However, transfection with miR-320a inhibitor reinforced trophoblast invasion in vitro. Luciferase assays verified that estrogen-related receptor-gamma (ERRγ) served as a direct target of miR-320a. Quantitative real-time polymerase chain reaction and Western blot demonstrated that excessive miR-320a expression downregulated ERRγ transcription and translation. Additionally, LPS supplementation showed excessive miR-320a expression and ERRγ downregulation. Impaired ERRγ and enhanced miR-320a expression occurred in PE placentas compared to controls. Pearson correlation and linear regression analysis revealed that miR-320a expression was negatively related to ERRγ expression in normal and pre-eclamptic placentas.

CONCLUSIONS

These findings indicate that miR-320a overexpression causes anomalous placentation by targeting ERRγ. Our research reveals the promising effect of miR-320a and the ERRγ functional loop on placentation.

Emblica officinalis extract downregulates pro-angiogenic molecules via upregulation of cellular and exosomal miR-375 in human ovarian cancer cells

Ovarian cancer (OC) is highly resistant to current treatment strategies based on a combination of surgery, chemotherapy and radiation therapy. We have recently demonstrated the anti-neoplastic effect of Amla extract (Emblica officinalis, AE) on OC cells in vitro and in vivo. We hypothesized that AE attenuates growth of OC through microRNA (miR)-regulated mechanism(s). The inhibitory effect of AE on proliferation, migration and invasiveness (P≤0.001) of SKOV3 cells and >90% attenuation of tumor growth in a xenograft mouse model suggested multiple targets. RT-qPCR analysis of microRNAs associated with OC showed a >2,000-fold increase in the expression of miR-375 in AE-treated SKOV3 cells that was blocked by an exogenous miR-375 inhibitor (P≤0.001). AE also decreased the gene and protein expression of IGF1R, a target of miR-375 (P≤0.001), and SNAIL1 (P≤0.002), an EMT-associated transcription factor that represses E-cadherin expression (P≤0.003). AE increased E-cadherin expression (P≤0.001). Treatment of SKOV3 cells with AE resulted in increased miR-375 in exosomes in the medium (P≤0.01). Finally, AE significantly decreased the expression of IGF1R and SNAIL1 proteins during attenuation of SKOV3-derived xenograft tumor. Together, these results show that AE modulates cancer cells and the tumor microenvironment via activation of miR-375 and by targeting IGF1R and SNAIL1 in OC cells.

MicroRNA‑320 targets mitogen‑activated protein kinase 1 to inhibit cell proliferation and invasion in epithelial ovarian cancer

Ovarian cancer is the second most frequently occurring cancer and the most fatal gynecological malignancy of all gynecological cancers worldwide. MicroRNAs (miR) have been reported to be downregulated or upregulated in a variety of human malignancies, and involved in the formation and progression of the majority of human cancers, including epithelial ovarian cancer (EOC). miR‑320 has been identified as a tumor suppressor in multiple human cancers. However, the expression levels, biological role and underlying mechanisms of miR‑320 in EOC remain to be elucidated. In the present study, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to detect miR‑320 expression in EOC tissues and cell lines. Following transfection with miR‑320 mimics, Cell Counting Kit 8 and cell invasion assays were utilized to investigate the effects of miR‑320 on EOC cell proliferation and invasion. Bioinformatic analysis, luciferase reporter assay, RT‑qPCR and western blotting were used to explore the underlying mechanism of how miR‑320 affects cell proliferation and invasion in EOC. Mitogen‑activated protein kinase (MAPK) 1 expression and its association with the miR‑320 expression level was examined in EOC tissues. The role of MAPK1 in EOC cells was additionally evaluated by using a loss‑of‑function assay. The results demonstrated that miR‑320 was markedly downregulated in EOC tissues and cell lines. A decreased miR‑320 expression was significantly correlated with the Federation of Gynecology and Obstetrics stage and lymph node metastasis of EOC patients. Additionally, reintroduction of miR‑320 expression suppressed cell proliferation and invasion in EOC. Furthermore, it was verified that MAPK1 is a direct target gene of miR‑320 in EOC. MAPK1 expression was markedly upregulated in EOC tissues and inversely correlated with miR‑320 expression. Furthermore, silencing of MAPK1 by RNA interference inhibited cell proliferation and invasion of EOC cells. Overall, the present study demonstrated that miR‑320 may act as a useful diagnostic and therapeutic target in the treatment of EOC.

miR-320a modulates cell growth and chemosensitivity via regulating ADAM10 in gastric cancer

MicroRNAs (miRNAs) may function as tumor suppressor or onco‑miRNAs and have critical roles in the pathogenesis of gastric cancer (GC). The exact function and mechanism of miRNA (miR)‑320a in GC remains to be elucidated. The present study performed gain‑ and loss‑of‑function analyses by transfecting cells with mimics or inhibitors and subsequently performing colony formation, proliferation and cisplatin‑sensitivity assays. Additionally, in vivo xenograft models were also performed. Bioinformatics algorithms, luciferase reporter activity assay and western blotting were used to predict the potential target of miR‑320a. Additionally, the effect of knockdown or overexpression of ADAM metallopeptidase domain 10 (ADAM10) on cell growth and chemosensitivity was examined. The expression of miR‑320a and ADAM10 was also determined in primary tumors. The present study revealed that the expression of miR‑320a was reduced in GC cells and ectopic miR‑320a expression significantly inhibited cell growth in vitro and in vivo and enhanced the sensitivity of GC cells to cisplatin. ADAM10 was a direct target of miR‑320a in GC. Knockdown of ADAM10 attenuated the proliferative ability of GC cells, and increased the sensitivity of GC cells to cisplatin. The upregulated ADAM10 accelerated cell growth rate and reduced the cisplatin‑sensitivity of cells. Clinically, a significantly negative correlation was identified between the expression of miR‑320a and mRNA levels of ADAM10 in tumors. The findings of the present study suggested that miR‑320a may function as a tumor suppressor in GC progression and potential therapeutic strategies for GC may be based on the miR‑320a/ADAM10 axis.

Characterization of a novel panel of plasma microRNAs that discriminates between Mycobacterium tuberculosis infection and healthy individuals

Cavities are important in clinical diagnosis of pulmonary tuberculosis (TB) infected by Mycobacterium tuberculosis. Although microRNAs (miRNAs) play a vital role in the regulation of inflammation, the relation between plasma miRNA and pulmonary tuberculosis with cavity remains unknown. In this study, plasma samples were derived from 89 cavitary pulmonary tuberculosis (CP-TB) patients, 89 non-cavitary pulmonary tuberculosis (NCP-TB) patients and 95 healthy controls. Groups were matched for age and gender. In the screening phase, Illumina high-throughput sequencing technology was employed to analyze miRNA profiles in plasma samples pooled from CP-TB patients, NCP-TB patients and healthy controls. During the training and verification phases, quantitative RT-PCR (qRT-PCR) was conducted to verify the differential expression of selected miRNAs among groups. Illumina high-throughput sequencing identified 29 differentially expressed plasma miRNAs in TB patients when compared to healthy controls. Furthermore, qRT-PCR analysis validated miR-769-5p, miR-320a and miR-22-3p as miRNAs that were differently present between TB patients and healthy controls. ROC curve analysis revealed that the potential of these 3 miRNAs to distinguish TB patients from healthy controls was high, with the area under the ROC curve (AUC) ranged from 0.692 to 0.970. Moreover, miR-320a levels were decreased in drug-resistant TB patients than pan-susceptible TB patients (AUC = 0.882). In conclusion, we identified miR-769-5p, miR-320a and miR-22-3p as potential blood-based biomarkers for TB. In addition, miR-320a may represent a biomarker for drug-resistant TB.

The effects of microRNA-98 inhibits cell proliferation and invasion by targeting STAT3 in nasopharyngeal carcinoma

MicroRNA-98 (miR-98) is downregulated in many tumors, and is closely related to tumor progression. In addition, it shows anticarcinogenic functions in various tumor. However, few study show that the biological function and regulatory mechanisms of miR-98 in nasopharyngeal carcinoma (NPC) progression. The identification and its target genes which regulate by dysregulated miRNAs may strengthen our understanding of the molecular mechanisms of NPC. In this study, we observe that miR-98 is not only significantly reduced in NPC tissues, but also decreased markedly in NPC cell lines. Moreover, silencing miR-98 expression studies not only show miR-98 induced cell proliferation, migration and invasion in vitro, but also it promoted xenograft tumor growth in vivo in NPC. Furthermore, western blot assay was used to detected the level of STAT3 protein and we demonstrate that miR-98 regulate cells poliferation, migration and invasion through directly modulating functional target STAT3 by directly binding its 3'-UTR. These findings illustrate miR-98 as a anticarcinogenic functions through targeting STAT3, the miR-98/STAT3 pathway gives new clues for understanding NPC carcinogenesis and provides novel therapeutic targetsfor NPC.

miR-320a functions as a suppressor for gliomas by targeting SND1 and β-catenin, and predicts the prognosis of patients

miR-320a downexpression contributes to tumorigenesis in several human cancers. However, the relevance of miR-320a to prognosis, proliferation and invasion in gliomas remains unclear. In this study, we demonstrated that miR-320a expression was decreased in human glioma tissues and cell lines. Moreover, miR-320a expression was inversely correlated with glioma grades and Ki-67 index, but positively correlated with patients’ survival. Contrarily, SND1 and β-catenin expressions were positively correlated with glioma grades and Ki-67 index, but inversely correlated with miR-320a expression and patients’ survival. Furthermore, two subgroups with distinct prognoses in our glioma patients of different grade, IDH status, age and KPS were identified according to expression of miR-320a, SND1 or β-catenin. Cox regression showed that miR-320a and SND1 were independent predictors and β-catenin was an auxiliary predictor for patients’ survival. miR-320a overexpression suppressed the G1/S phase transition, proliferation, migration and invasion of glioblastoma cells. Mechanistically, we validated SND1 and β-catenin as direct targets of miR-320a, and found that miR-320a overexpression increased SND1-inhibited tumor suppressor p21^WAF1 and decreased Smad2, Smad4, MMP2, MMP7 and cyclinD1, the pivotal downstream effectors of SND1 or β-catenin. Our findings demonstrate the potential values of miR-320a, SND1 and β-catenin as prognostic biomarkers and therapeutic candidates for malignant gliomas.

Overexpression of microRNA-132 enhances the radiosensitivity of cervical cancer cells by down-regulating Bmi-1

We examined the effects of microRNA-132 (miR-132) on Bmi-1 expression and radiosensitivity in HeLa, SiHa, and C33A cervical cancer (CC) cells and 104 CC patients. MiR-132 expression was decreased and Bmi-1 expression was increased in tumor tissues compared to adjacent normal tissues and in radiotherapy-resistant patients compared to radiotherapy-sensitive patients. MiR-132 expression and Bmi-1 mRNA expression were also negatively correlated in tumor tissues. HeLa, SiHa, and C33A cells were divided into blank, miR-132 negative control (NC), miR-132 inhibitor, miR-132 mimics, siBmi-1, and miR-132 inhibitor + siBmi-1 groups, after which expression of miR-132 and Bmi-1, and the interaction between them and cell survival, proliferation, and apoptosis were examined. Bmi-1 was confirmed as a target of miRNA-132. Survival was higher and apoptosis lower in the miR-132 inhibitor group than the blank group after various doses of radiation. By contrast, survival was lower and apoptosis higher in the miRNA-132 mimics and siBmi-1 groups than in the blank group. Moreover, miR-132 expression increased and Bmi-1 mRNA expression decreased in each group at radiation doses of 6 and 8 Gy. Finally, co-administration of radiotherapy and exogenous miR-132 inhibited the growth of HeLa cell transplant-induced tumors in nude mice more effectively than radiotherapy alone. These results suggest overexpression of miR-132 enhances the radiosensitivity of CC cells by down-regulating Bmi-1 and that miR-132 may be a useful new target for the treatment of CC.

ZKSCAN1 gene and its related circular RNA (circZKSCAN1) both inhibit hepatocellular carcinoma cell growth, migration, and invasion but through different signaling pathways

There is increasing evidence that circular RNA (circRNA) are involved in cancer development, but the regulation and function of human circRNA remain largely unknown. In this study, we demonstrated that ZKSCAN1, a zinc finger family gene, is expressed in both linear and circular (circZKSCAN1) forms of RNA in human hepatocellular carcinoma (HCC) tissues and cell lines. Here, we analyzed a cohort of 102 patients and found that expression of both ZKSCAN1mRNA and circZKSCAN1 was significantly lower (P < 0.05) in the HCC samples compared with that in matched adjacent nontumorous tissues by reverse transcription PCR (RT-PCR). The low expression level of ZKSCAN1 was only associated with tumor size (P = 0.032), while the cirZKSCAN1 levels varied in patients with different tumor numbers (P < 0.01), cirrhosis (P = 0.031), vascular invasion (P = 0.002), or microscopic vascular invasion (P = 0.002), as well as with the tumor grade (P < 0.001). Silencing both ZKSCAN1mRNA and circZKSCAN1 promoted cell proliferation, migration, and invasion. In contrast, overexpression of both forms of RNA repressed HCC progression in vivo and in vitro. Silencing or overexpression of both forms of RNA did not interfere with each other. RNA-seq revealed a very different molecular basis for the observed effects; ZKSCAN1mRNA mainly regulated cellular metabolism, while circZKSCAN1 mediated several cancer-related signaling pathways, suggesting a nonredundant role for ZKSCAN1mRNA and circRNA. In conclusion, our results revealed two post-translational products (ZKSCAN1mRNA and circZKSCAN1) that cooperated closely with one another to inhibit growth, migration, and invasion of HCC. cirZKSCAN1 might be a useful marker for the diagnosis of HCC.

MicroRNA-320a is downregulated in non-small cell lung cancer and suppresses tumor cell growth and invasion by directly targeting insulin-like growth factor 1 receptor

Accumulating evidence has demonstrated that microRNAs (miRs/miRNAs) are implicated in carcinogenesis and cancer progression, and can function as oncogenes or tumor suppressor genes in human cancer types. Previous profile studies of miRNA expression levels have revealed that miR-320a was downregulated in breast cancer, colon cancer, bladder cancer, glioblastoma and salivary adenoid cystic carcinoma. However, its expression level, potential functions and the mechanisms underlying its functions in non-small cell lung cancer (NSCLC) require further investigation. The present study investigated the expression level, biological roles and underlying molecular mechanisms of miR-320a in NSCLC. The expression levels of miR-320a in NSCLC tissue and cell lines were detected using the reverse transcription-quantitative polymerase chain reaction. Cell proliferation and Transwell invasion assays were performed to examine the effects of miR-320a on NSCLC cells. In addition, bioinformatic analysis, western blot analysis and luciferase reporter assays were performed to identify the direct gene target of miR-320a in NSCLC. In the present study it was demonstrated that miR-320a was significantly downregulated in NSCLC tissues and cell lines. Ectopic overexpression of miR-320a suppressed the proliferation and invasion of NSCLC cells. Further studies indicated that miR-320a directly targeted the 3'-untranslated region of insulin-like growth factor 1 receptor (IGF-1R) and suppressed its expression at the mRNA and protein levels. As well as restoring the miR-320a expression level, the knockdown of IGF-1R also decreased the growth and invasion of the NSCLC cells. These results suggested that miR-320a served as a tumor suppressor in the NSCLC cells by directly targeting IGF-1R. Therefore, miR-320a should be investigated as a therapeutic target for the treatment of NSCLC.

MicroRNA-194 represses glioma cell epithelial‑to‑mesenchymal transition by targeting Bmi1

MicroRNA-194 (miR-194) is frequently dysregulated in many types of cancer. However, the function of miR-194 in glioma remains unknown. In the present study, we aimed to investigate the biological functions of miR-194 in glioma and the potential molecular mechanism of miR-194 involved in glioma progression. We found that miR-194 expression was significantly reduced in glioma specimens and cell lines, as detected by real-time quantitative polymerase chain reaction (RT-qPCR) analysis. The overexpression of miR-194 inhibited while the suppression of miR-194 promoted cell migration, invasion and epithelial mesenchymal transition (EMT) in glioma cells. Bioinformatics analysis showed that the B cell-specific moloney murine leukemia virus insertion site 1 (Bmi1) was a direct target of miR-194, which was validated by dual-luciferase reporter assay, RT-qPCR and western blot analysis. The restoration of Bmi1 expression significantly abrogated the suppressive effect of miR-194 on glioma cell EMT. Taken together, the present study suggests that miR-194 inhibits glioma cell EMT by targeting Bmi1 providing novel insights into understanding the pathogenesis of glioma. The restoration of miR-194 may be a potential therapeutic strategy for glioma treatment.

Identification of MicroRNAs as Breast Cancer Prognosis Markers through the Cancer Genome Atlas

Breast cancer is the second-most common cancer and second-leading cause of cancer mortality in American women. The dysregulation of microRNAs (miRNAs) plays a key role in almost all cancers, including breast cancer. We comprehensively analyzed miRNA expression, global gene expression, and patient survival from the Cancer Genomes Atlas (TCGA) to identify clinically relevant miRNAs and their potential gene targets in breast tumors. In our analysis, we found that increased expression of 12 mature miRNAs-hsa-miR-320a, hsa-miR-361-5p, hsa-miR-103a-3p, hsa-miR-21-5p, hsa-miR-374b-5p, hsa-miR-140-3p, hsa-miR-25-3p, hsa-miR-651-5p, hsa-miR-200c-3p, hsa-miR-30a-5p, hsa-miR-30c-5p, and hsa-let-7i-5p -each predicted improved breast cancer survival. Of the 12 miRNAs, miR-320a, miR-361-5p, miR-21-5p, miR-103a-3p were selected for further analysis. By correlating global gene expression with miRNA expression and then employing miRNA target prediction analysis, we suggest that the four miRNAs may exert protective phenotypes by targeting breast oncogenes that contribute to patient survival. We propose that miR-320a targets the survival-associated genes RAD51, RRP1B, and TDG; miR-361-5p targets ARCN1; and miR-21-5p targets MSH2, RMND5A, STAG2, and UBE2D3. The results of our stringent bioinformatics approach for identifying clinically relevant miRNAs and their targets indicate that miR-320a, miR-361-5p, and miR-21-5p may contribute to breast cancer survival.

MicroRNAs serving as potential biomarkers and therapeutic targets in nasopharyngeal carcinoma: A critical review

Despite significant medical advancement, nasopharyngeal carcinoma (NPC) remains one of the most difficult cancers to detect and treat where it continues to prevail especially among the Asian population. miRNAs could act as tumour suppressor genes or oncogenes in NPC. They play important roles in the pathogenesis of NPC by regulating specific target genes which are involved in various cellular processes and pathways. In particular, studies on miRNAs related to the Epstein Barr virus (EBV)-encoded latent membrane protein one (LMP1) and EBVmiRNA- BART miRNA confirmed the link between EBV and NPC. Both miRNA and its target genes could potentially be exploited for prognostic and therapeutic strategies. They are also important in predicting the sensitivity of NPC to radiotherapy and chemotherapy. The detection of stable circulating miRNAs in plasma of NPC patients has raised the potential of miRNAs as novel diagnostic markers. To conclude, understanding the roles of miRNA in NPC will identify ways to improve the management of patients with NPC.

BMI1: A Biomarker of Hematologic Malignancies

BMI1 oncogene is a catalytic member of epigenetic repressor polycomb group proteins. It plays a critical role in the regulation of gene expression pattern and consequently several cellular processes during development, including cell cycle progression, senescence, aging, apoptosis, angiogenesis, and importantly self-renewal of adult stem cells of several lineages. Preponderance of evidences indicates that deregulated expression of PcG protein BMI1 is associated with several human malignancies, cancer stem cell maintenance, and propagation. Importantly, overexpression of BMI1 correlates with therapy failure in cancer patients and tumor relapse. This review discusses the diverse mode of BMI1 regulation at transcriptional, posttranscriptional, and posttranslational levels as well as at various critical signaling pathways regulated by BMI1 activity. Furthermore, this review highlights the role of BMI1 as a biomarker and therapeutic target for several subtypes of hematologic malignancies and the importance to target this biomarker for therapeutic applications.

miR-320a regulates cell proliferation and apoptosis in multiple myeloma by targeting pre-B-cell leukemia transcription factor 3

Aberrant expression of microRNAs (miRNAs) is implicated in cancer development and progression. While miR-320a is reported to be deregulated in many malignancy types, its biological role in multiple myeloma (MM) remains unclear. Here, we observed reduced expression of miR-320a in MM samples and cell lines. Ectopic expression of miR-320a dramatically suppressed cell viability and clonogenicity and induced apoptosis in vitro. Mechanistic investigation led to the identification of Pre-B-cellleukemia transcription factor 3 (PBX3) as a novel and direct downstream target of miR-320a. Interestingly, reintroduction of PBX3 abrogated miR-320a-induced MM cell growth inhibition and apoptosis. In a mouse xenograft model, miR-320a overexpression inhibited tumorigenicity and promoted apoptosis. Our findings collectively indicate that miR-320a inhibits cell proliferation and induces apoptosis in MM cells by directly targeting PBX3, supporting its utility as a novel and potential therapeutic agent for miRNA-based MM therapy.

Understanding the CREB1-miRNA feedback loop in human malignancies

cAMP response element binding protein 1 (CREB1, CREB) is a key transcription factor that mediates transcriptional responses to a variety of growth factors and stress signals. CREB1 has been shown to play a critical role in development and progression of tumors. MicroRNAs (miRNAs) are a class of non-coding RNAs. They post-transcriptionally regulate gene expression through pairing with the 3'-UTR of their target mRNAs and thus regulate initiation and progression of various types of human cancers. Recent studies have demonstrated that a number of miRNAs can be transcriptionally regulated by CREB1. Interestingly, CREB1 expression can also be modulated by miRNAs, thus forming a feedback loop. This review outlines the functional roles of CREB1, miRNA, and their interactions in human malignancies. This will help to define a relationship between CREB1 and miRNA in human cancer and develop novel therapeutic strategies.

Epigenetic regulators: Polycomb-miRNA circuits in cancer

Polycomb group (PcG) proteins belong to a family of epigenetic modifiers and play a key role in dynamic control of their target genes. Several reports have found that aberrations in PcG-microRNA (miRNA) interplay in various cancer types often associated with poor clinical prognosis. This review discusses important PcG-miRNA molecular networks which act as critical interfaces between chromatin remodeling, and transcriptional and post-transcriptional regulation of their target genes in cancer. Moreover, here are discussed several compounds influencing the activity of PcG proteins entered in clinical arena for the treatment of solid tumors, multiple myeloma and B lymphomas, thus highlighting the therapeutic potential of targeting this protein family.

MicroRNA-125b suppresses the epithelial-mesenchymal transition and cell invasion by targeting ITGA9 in melanoma

Increasing evidence has shown that aberrant miRNAs contribute to the development and progression of human melanoma. Previous studies have shown that miR-125b functions as a suppressor in malignant melanoma. However, the molecular function and mechanism by which miR-125b influences melanoma growth and invasion are still unclear. In this study, we aimed to investigate the role of miR-125b in melanoma progression and metastasis. We found that miR-125b expression is significantly downregulated in primary melanoma, and an even greater downregulation was observed in metastatic invasion. Restored expression of miR-125b in melanoma suppressed cell proliferation and invasion both in vitro and in vivo. Furthermore, our findings demonstrate that upregulating miR-125b significantly inhibits malignant phenotypes by repressing the expression of integrin alpha9 (ITGA9). Finally, our data reveal that upregulated expression of ITGA9 in melanoma tissues is inversely associated with miR-125b levels. Together, our results demonstrate that upregulation of ITGA9 in response to the decrease in miR-125b in metastatic melanoma is responsible for melanoma tumor cell migration and invasion.

Circulating micrornas associated with glycemic impairment and progression in Asian Indians

AIMS/HYPOTHESIS

Asian Indians have a high incidence of type 2 diabetes, but factors associated with glycemic progression in this population are not understood. MicroRNAs are emerging as important mediators of glucose homeostasis and have not been previously studied in Asian Indians. We examined microRNA (miR) expression associated with glycemic impairment and progression in Asian Indians from the San Francisco Bay Area. We studied 128 Asian Indians age 45-84 years without known cardiovascular disease and not taking diabetes medications. Oral glucose tolerance tests were performed at baseline and after 2.5 years. We quantified circulating miRs from plasma collected during the enrollment visit using a flow cytometry-based assay.

RESULTS

Glycemic impairment was present in 57 % (n = 73) at baseline. MiR-191 was positively associated with glycemic impairment (odds ratio (OR) 1.7 (95 % CI 1.2, 2.4), p < 0.01). The prevalence of glycemic progression after 2.5 years was 24 % (n = 23). Six miRs were negatively associated with glycemic progression: miR-122 (OR 0.5 (0.2, 0.8), p < 0.01), miR-15a (OR 0.6 (0.4, 0.9), p < 0.01), miR-197 (OR 0.6 (0.4, 0.9), p < 0.01), miR-320a (OR 0.6 (0.4, 0.9), p < 0.01), miR-423 (OR 0.6 (0.4, 0.9), p < 0.01), and miR-486 (OR 0.5 (0.3, 0.8), p < 0.01). Further multivariate adjustment did not attenuate these results.

CONCLUSIONS/INTERPRETATION

This is the first study to investigate circulating miRs associated with glycemic status among this high-risk ethnic group. Individual miRs were significantly associated with both glycemic impairment and glycemic progression. Further studies are needed to determine whether miR (s) might be useful clinical biomarkers for incident T2D in the Asian Indian population.

MiR-145, a microRNA targeting ADAM17, inhibits the invasion and migration of nasopharyngeal carcinoma cells

MiR-145 is downregulated and functions as a tumor suppressor in many malignancies. In this study, the biological function, molecular mechanism, and direct target genes of miR-145 in nasopharyngeal carcinoma (NPC) cells were investigated. Cell survival was detected by cell viability assay, and cell cycle was determined through flow cytometry. Invasion and migration of NPC cells were examined using cell invasion and wound healing assays, respectively. A disintegrin and metalloproteinase 17 (ADAM17) was verified as the target of miR-145 through luciferase reporter assay, qRT-PCR, and Western blot analysis. In NPC cell lines, miR-145 expression was significantly downregulated and ADAM17 protein expression was upregulated. ADAM17 was downregulated at the post-transcriptional level by miR-145 via the binding site of ADAM17-3'UTR. Transfection with miR-145 mimic suppressed cell growth and induced cell cycle arrest in the G0/G1 phase by upregulating key G0/G1 phase regulators, namely, p53 and p21. MiR-145 also inhibited cellular migration and invasion through targeting ADAM17 involving the regulation of EGFR and E-cadherin. Knockdown of ADAM17 elicited similar effects to that of miR-145 on NPC cells. This study reveals that miR-145 suppressed the invasion and migration of NPC cells by targeting ADAM17. Thus, miR-145 could be a therapeutic target for NPC.