miRNAs in breast cancer tumorigenesis (Review)

Recent progress in Surface-Enhanced Raman Spectroscopy detection of biomarkers in liquid biopsy for breast cancer

Breast cancer is the most commonly diagnosed cancer in women globally and a leading cause of cancer-related mortality. However, current detection methods, such as X-rays, ultrasound, CT scans, MRI, and mammography, have their limitations. Recently, with the advancements in precision medicine and technologies like artificial intelligence, liquid biopsy, specifically utilizing Surface-Enhanced Raman Spectroscopy (SERS), has emerged as a promising approach to detect breast cancer. Liquid biopsy, as a minimally invasive technique, can provide a temporal reflection of breast cancer occurrence and progression, along with a spatial representation of overall tumor information. SERS has been extensively employed for biomarker detection, owing to its numerous advantages such as high sensitivity, minimal sample requirements, strong multi-detection ability, and controllable background interference. This paper presents a comprehensive review of the latest research on the application of SERS in the detection of breast cancer biomarkers, including exosomes, circulating tumor cells (CTCs), miRNA, proteins and others. The aim of this review is to provide valuable insights into the potential of SERS technology for early breast cancer diagnosis.

Novel Strategies Using Sagacious Targeting for Site-Specific Drug Delivery in Breast Cancer Treatment: Clinical Potential and Applications

For more than a decade, researchers have been working to achieve new strategies and smart targeting drug delivery techniques and technologies to treat breast cancer (BC). Nanotechnology presents a hopeful strategy for targeted drug delivery into the building of new therapeutics using the properties of nanomaterials. Nanoparticles are of high regard in the field of diagnosis and the treatment of cancer. The use of these nanoparticles as an encouraging approach in the treatment of various cancers has drawn the interest of researchers in recent years. In order to achieve the maximum therapeutic effectiveness in the treatment of BC, combination therapy has also been adopted, leading to minimal side effects and thus an enhancement in the quality of life for patients. This review article compares, discusses and criticizes the approaches to treat BC using novel design strategies and smart targeting of site-specific drug delivery systems.

Assessing the Role of MicroRNAs in Predicting Breast Cancer Recurrence-A Systematic Review

Identifying patients likely to develop breast cancer recurrence remains a challenge. Thus, the discovery of biomarkers capable of diagnosing recurrence is of the utmost importance. MiRNAs are small, non-coding RNA molecules which are known to regulate genetic expression and have previously demonstrated relevance as biomarkers in malignancy. To perform a systematic review evaluating the role of miRNAs in predicting breast cancer recurrence. A formal systematic search of PubMed, Scopus, Web of Science, and Cochrane databases was performed. This search was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) checklist. A total of 19 studies involving 2287 patients were included. These studies identified 44 miRNAs which predicted breast cancer recurrence. Results from nine studies assessed miRNAs in tumour tissues (47.4%), eight studies included circulating miRNAs (42.1%), and two studies assessed both tumour and circulating miRNAs (10.5%). Increased expression of 25 miRNAs were identified in patients who developed recurrence, and decreased expression of 14 miRNAs. Interestingly, five miRNAs (miR-17-5p, miR-93-5p, miR-130a-3p, miR-155, and miR-375) had discordant expression levels, with previous studies indicating both increased and reduced expression levels of these biomarkers predicting recurrence. MiRNA expression patterns have the ability to predict breast cancer recurrence. These findings may be used in future translational research studies to identify patients with breast cancer recurrence to improve oncological and survival outcomes for our prospective patients.

Cancer-associated Fibroblasts Communicate with Breast Tumor Cells Through Extracellular Vesicles in Tumor Development

Breast cancer is the leading cause of cancer death among women worldwide. In solid tumors, the microenvironment plays a critical role in tumor development, and it has been described a communication between the different cell types that conform the stroma, including fibroblasts, pericytes, adipocytes, immune cells and cancer-associated fibroblasts. Intercellular communication is bidirectional, complex, multifactorial and is mediated by the secretion of molecules and extracellular vesicles. The extracellular vesicles are vesicles limited by two membranes that are secreted by normal and cancer cells into the extracellular space. Extracellular vesicle cargo is complex and includes proteins, miRNAs, DNA and lipids, and their composition is specific to their parent cells. Extracellular vesicles are taken up for neighboring or distant cells. Particularly, extracellular vesicles from breast cancer cells are taken up for fibroblasts and it induces the activation of fibroblasts into cancer-associated fibroblasts. Interestingly, cancer associated fibroblasts release extracellular vesicles that are taken up for breast cancer cells and promote migration, invasion, proliferation, epithelial-mesenchymal transition, changes in metabolism, chemoresistance, evasion of immune system and remodeling of extracellular matrix. In addition, the enrichment of specific cargos in extracellular vesicles of breast cancer patients has been suggested to be used as biomarkers of the disease. Here we review the current literature about the intercommunication between tumor cells and cancer associated fibroblasts through extracellular vesicles in breast cancer.

miRSCAPE - inferring miRNA expression from scRNA-seq data

Our understanding of miRNA activity at cellular resolution is thwarted by the inability of standard scRNA-seq protocols to capture miRNAs. We introduce a novel tool, miRSCAPE, to infer miRNA expression in a sample from its RNA-seq profile. We establish miRSCAPE's accuracy in 10 tumor and normal cohorts demonstrating its superiority over alternatives. miRSCAPE accurately infers cell type-specific miRNA activities (predicted versus observed fold-difference correlation ∼0.81) in two independent scRNA-seq datasets. We apply miRSCAPE to infer miRNA activities in scRNA clusters in pancreatic and lung adenocarcinomas, as well as in 56 cell types in the human cell landscape (HCL). In pancreatic and breast cancer scRNA-seq data, miRSCAPE recapitulates miRNAs associated with stemness and epithelial-mesenchymal transition (EMT) cell states, respectively. Overall, miRSCAPE recapitulates and refines miRNA biology at cellular resolution. miRSCAPE is freely available and is easily applicable to scRNA-seq data to infer miRNA activities at cellular resolution.

Prognostic Value and Biological Role of miR-126 in Breast Cancer

In eukaryotic organisms such as humans, some noncoding single-stranded RNAs (ncRNAs) contribute to regulating the expression of some genes before and after the transcription process, which in turn controls a number of vital physiological processes, including cell proliferation, differentiation, invasion, angiogenesis, and embryonic development. miR-126 is one of these miRNAs expressed exclusively in endothelial cells such as capillaries and vessels involved in controlling angiogenesis. In recent years, the link between miRs such as miR-126 and the pathology of breast cancer has attracted the attention of many researchers. Numerous studies have shown that miR-126 may be able to suppress tumor tissue metastasis or to increase tumor metastasis through complex molecular mechanisms. There is ample clinical evidence that miR-126 can be used as a biomarker to predict and diagnose breast cancer due to the increased or decreased expression of certain genes in breast cancer tissue. In this review, we discuss the association between the growth and metastasis (tumorigenesis) of breast cancer and miR-126, as well as the relationship between current research advances in the prognosis, diagnosis, and treatment of breast cancer and miR-126.

Regulation of micro-RNA, epigenetic factor by natural products for the treatment of cancers: Mechanistic insight and translational Association

From onset to progression, cancer is a ailment that might take years to grow. All common epithelial malignancies, have a long latency period, frequently 20 years or more, different gene may contain uncountable mutations if they are clinically detectable. MicroRNAs (miRNAs) are around 22nt non-coding RNAs that control gene expression sequence-specifically through translational inhibition or messenger degradation of RNA (mRNA). Epigenetic processes of miRNA control genetic variants through genomic DNA methylation, post-translation histone modification, rework of the chromatin, and microRNAs. The field of miRNAs has opened a new era in understanding small non-coding RNAs since discovering their fundamental mechanisms of action. MiRNAs have been found in viruses, plants, and animals through molecular cloning and bioinformatics approaches. Phytochemicals can invert the epigenetic aberrations, a leading cause of the cancers of various organs, and act as an inhibitor of these changes. The advantage of phytochemicals is that they only function on cells that cause cancer without affecting normal cells. Phytochemicals appear to play a significant character in modulating miRNA expression, which is linked to variations in oncogenes, tumor suppressors, and cancer-derived protein production, according to several studies. In addition to standard anti-oxidant or anti-inflammatory properties, the initial epigenetic changes associated with cancer prevention may be modulated by many polyphenols. In correlation with miRNA and epigenetic factors to treat cancer some of the phytochemicals, including polyphenols, curcumin, resveratrol, indole-3-carbinol are studied in this article.

Human microRNA similarity in breast cancer

MicroRNAs (miRNAs) play important roles in a variety of human diseases, including breast cancer. A number of miRNAs are up- and down-regulated in breast cancer. However, little is known about miRNA similarity and similarity network in breast cancer. Here, a collection of 272 breast cancer-associated miRNA precursors (pre-miRNAs) were utilized to calculate similarities of sequences, target genes, pathways and functions and construct a combined similarity network. Well-characterized miRNAs and their similarity network were highlighted. Interestingly, miRNA sequence-dependent similarity networks were not identified in spite of sequence–target gene association. Similarity networks with minimum and maximum number of miRNAs originate from pathway and mature sequence, respectively. The breast cancer-associated miRNAs were divided into seven functional classes (classes I–VII) followed by disease enrichment analysis and novel miRNA-based disease similarities were found. The finding would provide insight into miRNA similarity, similarity network and disease heterogeneity in breast cancer.

Recent Advances in Diagnostic and Therapeutic Approaches for Breast Cancer: A Comprehensive Review

A silent monster, breast cancer, is a challenging medical task for researchers. Breast cancer is a leading cause of death in women with respect to other cancers. A case of breast cancer is diagnosed among women every 19 seconds, and every 74 seconds, a woman dies of breast cancer somewhere in the world. Several risk factors, such as genetic and environmental factors, favor breast cancer development. This review tends to provide deep insights regarding the genetics of breast cancer along with multiple diagnostic and therapeutic approaches as problem-solving negotiators to prevent the progression of breast cancer. This assembled data mainly aims to discuss omics-based approaches to provide enthralling diagnostic biomarkers and emerging novel therapies to combat breast cancer. This review article intends to pave a new path for the discovery of effective treatment options.

Preparation, characterization, and in vitro tumor-suppressive effect of anti-miR-21-equipped RNA nanoparticles

MicroRNAs play an irreplaceable role in gene expression regulation. Upregulation of several miRNAs increases the risk of invasion and metastasis of breast cancer cells. An oncogenic miRNA, miR-21, is highly expressed in triple-negative breast cancer (TNBC) and is associated with tumor proliferation, invasion, carcinogenesis, prognosis, and therapeutic resistance. However, targeted delivery of therapeutic anti-miRNAs into cancer cells remains challenging, especially for TNBC. In this study, we report the application of an RNA nanotechnology-based platform for the targeted delivery of anti-miR-21 by epidermal growth factor receptor (EGFR) aptamer in vitro to TNBC and chemical-resistant breast cancer cells. RNA nanoparticles reduced cell viability and sensitized breast cancer cells to doxorubicin (DOX) treatment in vitro. Inhibition of miR-21 by RNA nanoparticles suppressed TNBC cell invasion, migration, and colony formation. The results indicate the potential application of nanotechnology-based delivery platforms in clinical anti-cancer therapeutics.

Regulation of microRNA-21 expression by natural products in cancer

Natural products have been of much interest in research studies owing to their wide pharmacological applications, chemical diversity, low side effects, and multitarget activities. Examples of these compounds include matrine, sulforaphane, silibinin, curcumin, berberin, resveratrol, and quercetin. Some of the present anticancer drugs, such as taxol, vincristine, vinblastine, and doxorubicin are also derived from natural products. The anti-carcinogenic effects of these products are partly mediated through modulation of microRNA-21 (miR-21) expression. To date, numerous downstream targets of miR-21 have been recognized, which include phosphatase and tensin homolog (PTEN), ras homolog gene family member B (RHOB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), programmed cell death 4 (PDCD4), signal transducer and activator of transcription (STAT)-3, and nuclear factor kappa B (NF-κB) pathways. These signaling pathways, their regulation by oncomiR-21 in cancer, and the modulating impact of natural products are the main focus of this review.

MicroRNA-1297 downregulation inhibits breast cancer cell epithelial-mesenchymal transition and proliferation in a FA2H-dependent manner

Breast cancer (BC) is one of the most common malignant tumors among women worldwide. MicroRNAs (miRs) may be involved in several types of human cancer, including gastric, liver, lung and breast cancer. The aim of the present study was to investigate the effect of miR-1297 on MDA-MB-231 cell epithelial-mesenchymal transition (EMT) and proliferation, and the underlying molecular mechanisms. MDA-MB-231 cells were transfected with miR-1297 inhibitor or inhibitor control for 48 h. Subsequently, MTT and flow cytometry assays indicated that miR-1297 inhibitor significantly decreased cell proliferation and induced apoptosis compared with the inhibitor control group. In addition, reverse transcription-quantitative PCR and western blotting suggested that miR-1297 inhibitor suppressed EMT in MDA-MB-231 cells compared with the inhibitor control group. TargetScan bioinformatics analysis and a dual-luciferase reporter gene assay were performed, which predicted that miR-1297 directly targeted fatty acid 2-hydroxylase (FA2H). Furthermore, MDA-MB-231 cells were transfected with control-plasmid or FA2H-plasmid for 48 h. The results demonstrated that FA2H overexpression decreased MDA-MB-231 cell proliferation and increased apoptosis compared with the control-plasmid group. Additionally, FA2H-plasmid increased E-cadherin expression levels, and reduced N-cadherin and matrix metalloproteinase 9 expression levels at both the protein and mRNA level compared with control-plasmid. Finally, MDA-MB-231 cells were transfected with control-small interfering (si)RNA, FA2H-siRNA, inhibitor control, miR-1297 inhibitor, miR-1297 inhibitor + control siRNA or miR-1297 inhibitor + FA2H-siRNA, and the results suggested that the biological effects of miR-1297 inhibitor were reversed by co-transfection with FA2H siRNA. In conclusion, the present study indicated that miR-1297/FA2H might serve as a novel potential biomarker and therapeutic target for BC.

Improved cancer inhibition by miR-143 with a longer passenger strand than natural miR-143

We improved miR-143, which inhibits the growth of cancer cells, by the replacement of the passenger strand. As a result, new miR-143 variants were developed with a single mismatch at the 4th position from the 3'-terminal of the guide strand and an RNA passenger strand with a G-rich flanking DNA region. A reporter gene assay showed that the 80% inhibitory concentration of the new miR-143, long miR-143, was 69 pM, which was three times lower than that of natural miR-143. Long miR-143 inhibited the growth of two cancer cell lines, HeLa-S3 and MIAPaCa-2, more effectively than natural miR-143. This method could be applied to other miRNA families and should be useful for the development of miRNA drugs.

Nanotechnology, in silico and endocrine-based strategy for delivering paclitaxel and miRNA: Prospects for the therapeutic management of breast cancer

Breast cancer is one of the most prevalent and reoccurring cancers and the second most common reason of death in women. Despite advancements in therapeutic strategies for breast cancer, early tumor recurrence and metastasis in patients indicate resistance to chemotherapeutic medicines, such as paclitaxel due to the abnormal expression of ER and EGF2 in breast cancer cells. Therefore, the development of alternatives to paclitaxel is urgently needed to overcome challenges involving drug resistance. An increasing number of studies has revealed miRNAs as novel natural alternative substances that play a crucial role in regulating several physiological processes and have a close, adverse association with several diseases, including breast cancer. Due to the therapeutic potential of miRNA and paclitaxel in cancer research, the current review focuses on the differential roles of various miRNAs in breast cancer development and treatment. miRNA delivery to a specific target site, the development of paclitaxel and miRNA formulations, and nanotechnological strategies for the delivery of nanopaclitaxel in the management of breast cancer are discussed. These strategies involve improving the cellular uptake and bioavailability and reducing the toxicity of free paclitaxel to achieve accumulation tumor site. Furthermore, a molecular docking study was performed to ascertain the enhanced anticancer activity of the nanoformulation of ANG1005 and Abraxane. An in silico analysis revealed that ANG1005 and Abraxane nanoformulations have superior and significantly enhanced interactions with the proteins α-tubulin and Bcl-2. Therefore, ANG1005 and Abraxane may be more suitable in the therapeutic management of breast cancer than the existing free paclitaxel. miRNAs can revert abnormal gene expression to normalcy; since miRNAs serve as tumor suppressors. Therefore, restoration of particular miRNAs levels as a replacement therapy may be an effective endocrine potential strategy for treating ER positive/ negative breast cancers.

Toward a holistic view of multiscale breast cancer molecular biomarkers

Powered by rapid technology developments, biomarkers become increasingly diverse, including those detected at genomic, transcriptomic, proteomic, metabolomic and cellular levels. While diverse sets of biomarkers have been utilized in breast cancer predisposition, diagnosis, prognosis, treatment and management, recent additions derived from lincRNA, circular RNA, circulating DNA together with its methylated and hydroxymethylated forms and immune signatures are likely to further transform clinical practice. Here, we take breast cancer as an example of heterogeneous diseases that require many informed decisions from treatment to care to review the huge variety of biomarkers. By assessing the advantages and limitations of modern biomarkers in diverse use scenarios, this article outlines the prospects and challenges of releasing complimentary advantages by augmentation of multiscale molecular biomarkers.

Luteolin inhibits proliferation and induces apoptosis of human melanoma cells in vivo and in vitro by suppressing MMP-2 and MMP-9 through the PI3K/AKT pathway

Since the incidence rate of malignant melanoma is increasing annually, development of drugs against melanoma cell metastasis has become more urgent. Luteolin, a naturally occurring flavonoid, is abundant in our daily dietary intake and exhibits a wide spectrum of pharmacological properties. However, the potential anti-cancer role of luteolin in melanoma cells has not been fully investigated. In this study, we have explored whether luteolin inhibits the migration and invasion of A375 human melanoma cells and further elucidated the underlying anti-cancer molecular mechanism of luteolin in melanoma cells. A proliferation assay, flow cytometry and an apoptosis assay were applied to detect the effect of luteolin on the growth and apoptosis of A375 cells. Wound healing assay and transwell invasion assay were used to explore the impact of luteolin on the migration and invasion of A375 cells. Real-time quantitative PCR, western blot and immunofluorescence analysis were used to investigate the effects of luteolin on the expressions of MMP-2, MMP-9 and PI3K/AKT1 in A375 cells. A xenograft tumor animal model was used to investigate the anti-cancer effect of luteolin on the growth of the A375 cells in vivo. Our data indicated that luteolin significantly inhibited the proliferation, migration and invasion of A375 cells and induced the apoptosis of A375 cells in a concentration-dependent manner. Moreover, luteolin reduced the expressions of MMP-2 and MMP-9 and increased the expression of TIMP-1 and TIMP-2. Furthermore, luteolin significantly inhibited the tumor growth of A375 cells in a xenograft mouse model. The immunofluorescence and immunoblotting assays indicated that luteolin inhibited the phosphorylation of AKT1 and PI3K. In conclusion, both in vivo and in vitro studies showed that luteolin inhibited the proliferation and induced the apoptosis of A375 human melanoma cells by reducing the expressions of MMP-2 and MMP-9 through the PI3K/AKT pathway. Overall, luteolin can be considered as a promising anti-cancer agent for the treatment of human melanoma.

A label-free, ultra-highly sensitive and multiplexed SERS nanoplasmonic biosensor for miRNA detection using a head-flocked gold nanopillar

The combination of head-flocked gold nanopillars and sandwich DNA probes is an advanced label-free, ultra-high sensitive, multiplexed nanoplasmonic detection system of circulating miRNAs for cancer diagnosis and prognosis.

Recurrence prediction using microRNA expression in hormone receptor positive breast cancer during tamoxifen treatment

PURPOSE

To identify miRNAs associated with distant recurrence during tamoxifen treatment and build a recurrence prediction model.

MATERIALS AND METHODS

We measured the expression of five miRNAs (miR-134, miR-125b-5P, miRNA-30a, miR-10a-5p and miR-222). A total of 176 tumour tissues from 176 patients who had hormone receptor positive breast cancer with tamoxifen treatment were used to measure miRNA expression using quantitative real-time PCR (qRT-PCR).

RESULTS

The five miRNAs were all up-regulated in distant recurrence cases within 5 years after surgery and during tamoxifen treatment. Kaplan-Meier survival analyses based on expression cut-offs determined by receiver characteristics curves (ROC) showed that high expression of miR-134, miR-125b-5P, miRNA-30a, miR-10a-5p and miR-222 were significantly (log-rank p-value =0.006, p-value <0.0001, p-value <0.0001, p-value <0.0001 and p-value <0.0001, respectively) associated with short relapse-free time. Our results were used to build a combined 3 miRNAs expression model. It could be used to categorize high-risk subset of patients with short relapse-free survival (AUC =0.891, p-value <0.0001).

CONCLUSIONS

Distant recurrence during tamoxifen treatment of hormone positive breast cancer might be affected by tamoxifen resistance related miRNAs. Such distant recurrence can be predicted using miRNA measurement.

Evaluation of MiR-21 and MiR-10b Expression of Human Breast Cancer in West Sumatera

BACKGROUND

Abnormal expression of several microRNAs (miRNAs) has been demonstrated in many types of cancer tumor tissue. The miR-10b and miR-21 are an oncogenic miRNAs which play role in proliferation and invasion of Breast Cancer (BC) tumorigenesis. The aim of this study was to evaluate the miR-21 and miR-10b expression in BC in West Sumatran women, Indonesia.

MATERIALS AND METHODS

A total of 40 samples, consisting of 30 samples of breast cancer tissues (BC) and 10 samples of fibroadenoma tissues (FATs) as control and non-cancerous were analyzed. The miR-21 and miR-10b expression of each sample were investigated by using realtime PCR, followed by universal Reverse Transcription (RT) then real-time PCR amplification with specific primers. Hsa-miR-16-5p LNA PCR primer was used as an endogenous control.

RESULTS

The results showed that the expression level of miR-21 was more than 4 times higher in BC than in FATs. The expression level of miR-10b was lower in BC than FATs, by a factor of 3.34 fold. Both these differences were statistically different (p = 0.001).

CONCLUSION

In this study it was concluded that for this sample of West Sumatran Women miR-21 expression in BC was higher than in FATs, whereas miR-10b was lower in BC than in FATs.

Modulation of oncogenic transcription factors by bioactive natural products in breast cancer

Carcinogenesis, a multi-step phenomenon, characterized by alterations at genetic level and affecting the main intracellular pathways controlling cell growth and development. There are growing number of evidences linking oncogenes to the induction of malignancies, especially breast cancer. Modulations of oncogenes lead to gain-of-function signals in the cells and contribute to the tumorigenic phenotype. These signals yield a large number of proteins that cause cell growth and inhibit apoptosis. Transcription factors such as STAT, p53, NF-κB, c-JUN and FOXM1, are proteins that are conserved among species, accumulate in the nucleus, bind to DNA and regulate the specific genes targets. Oncogenic transcription factors resulting from the mutation or overexpression following aberrant gene expression relay the signals in the nucleus and disrupt the transcription pattern. Activation of oncogenic transcription factors is associated with control of cell cycle, apoptosis, migration and cell differentiation. Among different cancer types, breast cancer is one of top ten cancers worldwide. There are different subtypes of breast cancer cell-lines such as non-aggressive MCF-7 and aggressive and metastatic MDA-MB-231 cells, which are identified with distinct molecular profile and different levels of oncogenic transcription factor. For instance, MDA-MB-231 carries mutated and overexpressed p53 with its abnormal, uncontrolled downstream signalling pathway that account for resistance to several anticancer drugs compared to MCF-7 cells with wild-type p53. Appropriate enough, inhibition of oncogenic transcription factors has become a potential target in discovery and development of anti-tumour drugs against breast cancer. Plants produce diverse amount of organic metabolites. Universally, these metabolites with biological activities are known as "natural products". The chemical structure and function of natural products have been studied since 1850s. Investigating these properties leaded to recognition of their molecular effects as anticancer drugs. Numerous natural products extracted from plants, fruits, mushrooms and mycelia, show potential inhibitory effects against several oncogenic transcription factors in breast cancer. Natural compounds that target oncogenic transcription factors have increased the number of candidate therapeutic agents. This review summarizes the current findings of natural products in targeting specific oncogenic transcription factors in breast cancer.

Doxycycline inhibits breast cancer EMT and metastasis through PAR-1/NF-κB/miR-17/E-cadherin pathway

Doxycycline displays high efficiency for cancer therapy. However, the molecular mechanism is poorly understood. In our previous study, doxycycline was found to suppress tumor progression by directly targeting proteinase-activated receptor 1 (PAR1). In this study, microRNAs were found to be involved in PAR1-mediated anti-tumor effects of doxycycline. Among these miRNAs, miR-17 was found to promote breast cancer cell metastasis both in vivo and in vitro. Moreover, miR-17 could reverse partial doxycycline inhibition effects on breast cancer. Employing luciferase and chromatin immunoprecipitation assays, nuclear factor-kappaB (NF-κB) was found to bind miR-17 promoters. Furthermore, E-cadherin was identified as the target gene of miR-17. These results showed that miR-17 can resist the inhibitory effects of doxycycline on breast cancer epithelial–mesenchymal transformation (EMT) by targeting E-cadherin.

Modeling miRNA-mRNA interactions that cause phenotypic abnormality in breast cancer patients

Background

The dysregulation of microRNAs (miRNAs) alters expression level of pro-oncogenic or tumor suppressive mRNAs in breast cancer, and in the long run, causes multiple biological abnormalities. Identification of such interactions of miRNA-mRNA requires integrative analysis of miRNA-mRNA expression profile data. However, current approaches have limitations to consider the regulatory relationship between miRNAs and mRNAs and to implicate the relationship with phenotypic abnormality and cancer pathogenesis.

Methodology/Findings

We modeled causal relationships between genomic expression and clinical data using a Bayesian Network (BN), with the goal of discovering miRNA-mRNA interactions that are associated with cancer pathogenesis. The Multiple Beam Search (MBS) algorithm learned interactions from data and discovered that hsa-miR-21, hsa-miR-10b, hsa-miR-448, and hsa-miR-96 interact with oncogenes, such as, CCND2, ESR1, MET, NOTCH1, TGFBR2 and TGFB1 that promote tumor metastasis, invasion, and cell proliferation. We also calculated Bayesian network posterior probability (BNPP) for the models discovered by the MBS algorithm to validate true models with high likelihood.

Conclusion/Significance

The MBS algorithm successfully learned miRNA and mRNA expression profile data using a BN, and identified miRNA-mRNA interactions that probabilistically affect breast cancer pathogenesis. The MBS algorithm is a potentially useful tool for identifying interacting gene pairs implicated by the deregulation of expression.

Secreted molecules inducing epithelial-to-mesenchymal transition in cancer development

The epithelial-mesenchymal transition (EMT) is a biologic process that allows a polarized epithelial cell to undergo multiple biochemical changes that enable it to assume a mesenchymal cell phenotype. EMT is involved in embryo development, wound healing, tissue regeneration, organ fibrosis and has also been proposed as the critical mechanism for the acquisition of malignant phenotypes by epithelial cancer cells. These cells have been shown to acquire a mesenchymal phenotype when localized at the invasive front of primary tumours increasing aggressiveness, invasiveness, metastatic potential and resistance to chemotherapy. There is now increasing evidence demonstrating that a crucial role in the development of this process is played by factors secreted by cells of the tumour microenvironment or by the tumour cells themselves. This review summarises the current knowledge of EMT induction in cancer by paracrine or autocrine mechanisms, by exosomes or free proteins and miRNAs.

High expression of GNA13 is associated with poor prognosis in hepatocellular carcinoma

Guanine nucleotide binding protein alpha 13 (GNA13) has been found to play critical roles in the development of several human cancers. However, little is known about GNA13 expression and its clinical significance in hepatocellular carcinoma (HCC). In our study, GNA13 was reported to be significantly up-regulated in HCC tissues, and this was correlated with several clinicopathological parameters, including tumor multiplicity (P = 0.004), TNM stage (P = 0.002), and BCLC stage (P = 0.010). Further Cox regression analysis suggested that GNA13 expression was an independent prognostic factor for overall survival (P = 0.014) and disease-free survival (P = 0.005). Moreover, we found that overexpression of GNA13 couldn’t promote cell proliferation in vitro, but could significantly increase the invasion ability of HCC cells. Together, our study demonstrates GNA13 may be served as a prognostic biomarker for HCC patients after curative hepatectomy, in which high expression of GNA13 suggests poor prognosis of HCC patients.

MicroRNA-200c is involved in proliferation of gastric cancer by directly repressing p27Kip1

P27^Kip1, also known as Cyclin-dependent kinase inhibitor 1B, is an important check-point protein in the cell cycle. It has been identified that although as a tumor suppressor, P27^Kip1 is expressed in different cancer cell types, which shows the therapeutic potential in tumor genesis. In this study, we examined the upstream regulatory mechanism of P27^Kip1 at the microRNA (miRNA) level in gastric carcinogenesis. We used bioinformatics to predict that microRNA-200c (miR-200c) might be a direct upstream regulator of P27^Kip1. It was also verified in gastric epithelial-derived cell lines that overexpression of miR-200c significantly inhibited the expression levels of P27^Kip1, whereas knockdown of miR-200c promoted P27^Kip1 expression in AGS and BGC-823 cells. Furthermore, we identified the direct binding of miR-200c on the P27^Kip1 3′ -UTR sequence by luciferase assay. MiR-200c could enhance the colony formation of cells by repressing P27^Kip1 expression. In addition, the negative correlation between P27^Kip1 and miR-200c in human gastric cancer tissues and matched normal tissues further supported the tumor-promoting action of miR-200c in vivo. Our finding suggested that miR-200c directly regulates the expression of P27^Kip1 and promotes cell growth in gastric cancer as an oncogene, which may provide new clues to treatment.

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miR-200c is involved in the proliferation of gastric cancer cell lines.

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P27Kip1 is a direct downstream target of miR-200c.

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miR-200c is determined an oncogene in human gastric cancer tissue species.

Distinct Small RNA Signatures in Extracellular Vesicles Derived from Breast Cancer Cell Lines

Breast cancer is a heterogeneous disease, and different subtypes of breast cancer show distinct cellular morphology, gene expression, metabolism, motility, proliferation, and metastatic potential. Understanding the molecular features responsible for this heterogeneity is important for correct diagnosis and better treatment strategies. Extracellular vesicles (EVs) and their associated molecules have gained much attention as players in intercellular communication, ability to precondition specific organs for metastatic invasion, and for their potential role as circulating cancer biomarkers. EVs are released from the cells and contain proteins, DNA, and long and small RNA species. Here we show by high-throughput small RNA-sequencing that EVs from nine different breast cancer cell lines share common characteristics in terms of small RNA content that are distinct from their originating cells. Most strikingly, a highly abundant small RNA molecule derived from the nuclear 28S rRNA is vastly enriched in EVs. The miRNA profiles in EVs correlate with the cellular miRNA expression pattern, but with a few exceptions that includes miR-21. This cancer-associated miRNA is retained in breast cancer cell lines. Finally, we report that EVs from breast cancer cell lines cluster together based on their small RNA signature when compared to EVs derived from other cancer cell lines. Altogether, our data demonstrate that breast cancer cell lines manifest a specific small RNA signature in their released EVs. This opens up for further evaluation of EVs as breast cancer biomarkers.

Emerging role of microRNA-21 in cancer

MicroRNAs (miRs) are a class of single-stranded RNA molecules of 15-27 nucleotides in length that regulate gene expression at the post-translational level. miR-21 is one of the earliest identified cancer-promoting 'oncomiRs', targeting numerous tumor suppressor genes associated with proliferation, apoptosis and invasion. The regulation of miR-21 and its role in carcinogenesis have been extensively investigated. Recent studies have focused on the diagnostic and prognostic value of miR-21 as well as its implication in the drug resistance of human malignancies. The further use of miR-21 as a biomarker and target for cancer treatments is likely to improve the outcome for patients with cancer. The present review highlights recent findings associated with the importance of miR-21 in hematological and non-hematological malignancies.

Genome-wide identification of target genes for miR-204 and miR-211 identifies their proliferation stimulatory role in breast cancer cells

MiR-204 and miR-211 (miR-204/211) share the same seed site sequence, targeting many of the same genes. Their role in cancer development remains controversial, as both cell proliferative and suppressive effects have been identified. This study aimed to address the relationship between the two structurally similar microRNAs (miRs) by examining their target genes in depth as well as to reveal their contribution in breast cancer cells. Genome-wide pathway analysis with the dysregulated genes after overexpression of either of the two miRs in MCF-7 breast cancer cell identified the “Cancer”- and “Cell signaling”-related pathway as the top pathway for miR-204 and miR-211, respectively. The majority of the target genes for both miRs notably comprised ones that have been characterized to drive cells anti-tumorigenic. Accordingly, the miRs induced the proliferation of MCF-7 and MDA-MB-231 cells, judged by cell proliferation as well as colony forming assay. Tumor suppressors, MX1 and TXNIP, were proven to be direct targets of the miRs. In addition, a high association was observed between miR-204 and miR-211 expression in breast cancer tissue. Our results indicate that miR-204/211 serve to increase cell proliferation at least in MCF-7 and MDA-MB-231 breast cancer cells by downregulating tumor suppressor genes.

MicroRNA expression profiling identifies decreased expression of miR-205 in inflammatory breast cancer

Inflammatory breast cancer is the most aggressive form of breast cancer. Identifying new biomarkers to be used as therapeutic targets is in urgent need. Messenger RNA expression profiling studies have indicated that inflammatory breast cancer is a transcriptionally heterogeneous disease, and specific molecular targets for inflammatory breast cancer have not been well established. We performed microRNA expression profiling in inflammatory breast cancer in comparison with locally advanced noninflammatory breast cancer in this study. Although many microRNAs were differentially expressed between normal breast tissue and tumor tissue, most of them did not show differential expression between inflammatory and noninflammatory tumor samples. However, by microarray analysis, quantitative reverse transcription PCR, and in situ hybridization, we showed that microRNA-205 expression was decreased not only in tumor compared with normal breast tissue, but also in inflammatory breast cancer compared with noninflammatory breast cancer. Lower expression of microRNA-205 correlated with worse distant metastasis-free survival and overall survival in our cohort. A small-scale immunohistochemistry analysis showed coexistence of decreased microRNA-205 expression and decreased E-cadherin expression in some ductal tumors. MicroRNA-205 may serve as a therapeutic target in advanced breast cancer including inflammatory breast cancer.

Canine Mammary Carcinomas: A Comparative Analysis of Altered Gene Expression

Breast cancer represents the second most frequent neoplasm in humans and sexually intact female dogs after lung and skin cancers, respectively. Many similar features in human and dog cancers including, spontaneous development, clinical presentation, tumor heterogeneity, disease progression and response to conventional therapies have supported development of this comparative model as an alternative to mice. The highly conserved similarities between canine and human genomes are also key to this comparative analysis, especially when compared to the murine genome. Studies with canine mammary tumor (CMT) models have shown a strong genetic correlation with their human counterparts, particularly in terms of altered expression profiles of cell cycle regulatory genes, tumor suppressor and oncogenes and also a large group of non-coding RNAs or microRNAs (miRNAs). Because CMTs are considered predictive intermediate models for human breast cancer, similarities in genetic alterations and cancer predisposition between humans and dogs have raised further interest. Many cancer-associated genetic defects critical to mammary tumor development and oncogenic determinants of metastasis have been reported and appear to be similar in both species. Comparative analysis of deregulated gene sets or cancer signaling pathways has shown that a significant proportion of orthologous genes are comparably up- or down-regulated in both human and dog breast tumors. Particularly, a group of cell cycle regulators called cyclin-dependent kinase inhibitors (CKIs) acting as potent tumor suppressors are frequently defective in CMTs. Interestingly, comparative analysis of coding sequences has also shown that these genes are highly conserved in mammals in terms of their evolutionary divergence from a common ancestor. Moreover, co-deletion and/or homozygous loss of the INK4A/ARF/INK4B (CDKN2A/B) locus, encoding three members of the CKI tumor suppressor gene families (p16/INK4A, p14ARF and p15/INK4B), in many human and dog cancers including mammary carcinomas, suggested their important conserved genetic order and localization in orthologous chromosomal regions. miRNAs, as powerful post-transcriptional regulators of most of the cancer-associated genes, have not been well evaluated to date in animal cancer models. Comprehensive expression profiles of miRNAs in CMTs have revealed their altered regulation showing a strong correlation with those found in human breast cancers. These genetic correlations between human and dog mammary cancers will greatly advance our understanding of regulatory mechanisms involving many critical cancer-associated genes that promote neoplasia and contribute to the promising development of future therapeutics.

Exosomes in development, metastasis and drug resistance of breast cancer

Transport through the cell membrane can be divided into active, passive and vesicular types (exosomes). Exosomes are nano-sized vesicles released by a variety of cells. Emerging evidence shows that exosomes play a critical role in cancers. Exosomes mediate communication between stroma and cancer cells through the transfer of nucleic acid and proteins. It is demonstrated that the contents and the quantity of exosomes will change after occurrence of cancers. Over the last decade, growing attention has been paid to the role of exosomes in the development of breast cancer, the most life-threatening cancer in women. Breast cancer could induce salivary glands to secret specific exosomes, which could be used as biomarkers in the diagnosis of early breast cancer. Exosome-delivered nucleic acid and proteins partly facilitate the tumorigenesis, metastasis and resistance of breast cancer. Exosomes could also transmit anti-cancer drugs outside breast cancer cells, therefore leading to drug resistance. However, exosomes are effective tools for transportation of anti-cancer drugs with lower immunogenicity and toxicity. This is a promising way to establish a drug delivery system.

MicroRNAs: New Biomarkers for Diagnosis, Prognosis, Therapy Prediction and Therapeutic Tools for Breast Cancer

Dysregulation of microRNAs (miRNAs) is involved in the initiation and progression of several human cancers, including breast cancer (BC), as strong evidence has been found that miRNAs can act as oncogenes or tumor suppressor genes. This review presents the state of the art on the role of miRNAs in the diagnosis, prognosis, and therapy of BC. Based on the results obtained in the last decade, some miRNAs are emerging as biomarkers of BC for diagnosis (i.e., miR-9, miR-10b, and miR-17-5p), prognosis (i.e., miR-148a and miR-335), and prediction of therapeutic outcomes (i.e., miR-30c, miR-187, and miR-339-5p) and have important roles in the control of BC hallmark functions such as invasion, metastasis, proliferation, resting death, apoptosis, and genomic instability. Other miRNAs are of interest as new, easily accessible, affordable, non-invasive tools for the personalized management of patients with BC because they are circulating in body fluids (e.g., miR-155 and miR-210). In particular, circulating multiple miRNA profiles are showing better diagnostic and prognostic performance as well as better sensitivity than individual miRNAs in BC. New miRNA-based drugs are also promising therapy for BC (e.g., miR-9, miR-21, miR34a, miR145, and miR150), and other miRNAs are showing a fundamental role in modulation of the response to other non-miRNA treatments, being able to increase their efficacy (e.g., miR-21, miR34a, miR195, miR200c, and miR203 in combination with chemotherapy).

MicroRNA-31 controls G protein alpha-13 (GNA13) expression and cell invasion in breast cancer cells

BACKGROUND

Gα13 (GNA13) is the α subunit of a heterotrimeric G protein that mediates signaling through specific G protein-coupled receptors (GPCRs). Our recent study showed that control of GNA13 expression by specific microRNAs (miRNAs or miRs) is important for prostate cancer cell invasion. However, little is known about the control of GNA13 expression in breast cancers. This project was carried out to determine (i) whether enhanced GNA13 expression is important for breast cancer cell invasion, and (ii) if so, the mechanism of deregulation of GNA13 expression in breast cancers.

METHODS

To determine the probable miRNAs regulating GNA13, online miRNA target prediction tool Targetscan and Luciferase assays with GNA13-3'-UTR were used. Effect of miRNAs on GNA13 mRNA, protein and invasion was studied using RT-PCR, western blotting and in vitro Boyden chamber assay respectively. Cell proliferation was done using MTT assays.

RESULTS

Overexpression of GNA13 in MCF-10a cells induced invasion, whereas knockdown of GNA13 expression in MDA-MB-231 cells inhibited invasion. Expression analysis of miRNAs predicted to bind the 3'-UTR of GNA13 revealed that miR-31 exhibited an inverse correlation to GNA13 protein expression in breast cancer cells. Ectopic expression of miR-31 in MDA-MB-231 cells significantly reduced GNA13 mRNA and protein levels, as well as GNA13-3'-UTR-reporter activity. Conversely, blocking miR-31 activity in MCF-10a cells induced GNA13 mRNA, protein and 3'-UTR reporter activity. Further, expression of miR-31 significantly inhibited MDA-MB-231 cell invasion, and this effect was partly rescued by ectopic expression of GNA13 in these cells. Examination of 48 human breast cancer tissues revealed that GNA13 mRNA levels were inversely correlated to miR-31 levels.

CONCLUSIONS

These data provide strong evidence that GNA13 expression in breast cancer cells is regulated by post-transcriptional mechanisms involving miR-31. Additionally our data shows that miR-31 regulates breast cancer cell invasion partially via targeting GNA13 expression in breast cancer cells. Loss of miR-31 expression and increased GNA13 expression could be used as biomarkers of breast cancer progression.

Efficacy of TCH/TEC neoadjuvant chemotherapy for the treatment of HER-2-overexpressing breast cancer

The aim of the present study was to observe the efficacy of neoadjuvant trastuzumab combined with docetaxel and carboplatin (TCH), and docetaxel, epirubicin and cyclophosphamide (TEC) chemotherapy in human epidermal growth factor receptor-2 (HER-2)-overexpressing breast cancer. The total cohort of 64 cases of HER-2-overexpressing breast cancer patients was divided into two groups according to their treatment preferences: The TCH group, consisting of 39 patients, and the TEC group, consisting of 25 patients. The neoadjuvant chemotherapy was continued for six cycles prior to comparison of the treatment efficacy. The TCG and TEC groups exhibited an overall response rate of 94.9 and 72.0% (37/39 and 18/25 cases; P<0.05), respectively, and a pathological complete response (pCR; defined as the presence of no invasive or in situ residual tumors in the breast) rate of 69.2 and 32.0% (27/39 and 8/25 cases; P<0.05), respectively. Furthermore, no significant differences were identified between the two groups of patients in terms of adverse reactions, such as cardiac dysfunction, bone marrow suppression and liver function impairment. In the present study, the treatment of HER-2-overexpressing breast cancer patients with TCH neoadjuvant chemotherapy demonstrated more favorable efficacy and a higher pCR rate when compared with the TEC-treated group.

A summary for molecular regulations of miRNAs in breast cancer

BACKGROUND

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death among women worldwide. MicroRNAs (miRNAs) are naturally-occurring, non-coding small RNA molecules that can modulate protein coding-genes, which makes it contributing to nearly all the physiological and pathological processes. Progression of breast cancer and resistance to endocrine therapies have been attributed to the possibility of hormone-responsive miRNAs involved in the regulation of certain signaling pathways.

METHODOLOGY

This review introduces better understanding of miRNAs to provide promising advances for treatment. miRNAs have multiple targets, and they were found to regulate different signaling pathways; consequently it is important to characterize their mechanisms of action and their cellular targets in order to introduce miRNAs as novel and promising therapies.

RESULTS

This review summarizes the molecular mechanisms of miRNAs in TGF-beta signaling, apoptosis, metastasis, cell cycle, ER-signaling, and drug resistance.

CONCLUSION

Finally, miRNAs will be introduced as promising molecules to be used in the fight against breast cancer and its developed drug resistance.

Technology in MicroRNA Profiling: Circulating MicroRNAs as Noninvasive Cancer Biomarkers in Breast Cancer

This report describes technologies to identify and quantify microRNAs (miRNAs) as potential cancer biomarkers, using breast cancer as an example. Most breast cancer patients are not diagnosed until the disease has advanced to later stages, which decreases overall survival rates. Specific miRNAs are up- or downregulated in breast cancer patients at various stages, can be detected in plasma and serum, and have shown promising preliminary clinical sensitivity and specificity for early cancer diagnosis or staging. Nucleic acid testing methods to determine relative concentrations of selected miRNAs include reverse transcription, followed by quantitative PCR (RT-qPCR), microarrays, and next-generation sequencing (NGS). Of these methods, NGS is the most powerful approach for miRNA biomarker discovery, whereas RT-qPCR shows the most promise for eventual clinical diagnostic applications.

The fusion of two worlds: non-coding RNAs and extracellular vesicles--diagnostic and therapeutic implications (Review)

The role of the extracellular non-coding RNAs, particularly microRNAs present in tumor-derived extravesicles, has been intensively exploited in human cancer as a promising tool for diagnostic and prognostic purposes. Current knowledge on exosomes shows an important role not only as vehicles in the intercellular communication, but the transfer of their content can specifically modulate the surrounding microenvironment, leading to tumor development and progression and affecting therapy response. Based on this, much effort has focused on understanding the mechanisms behind the biology of exosomes and their closely interaction with non-coding RNAs as an efficient tool in tumor diagnostic and therapy. Here we summarize the current knowledge on extracellular and exosomes-enclosed non-coding RNAs, and their importance as potential biomarkers and mediators of intercellular communication in tumor biology.

Critical role of miR-10b in transforming growth factor-β1-induced epithelial-mesenchymal transition in breast cancer

Epithelial-mesenchymal transition (EMT) is a key process in the tumor metastatic cascade that is characterized by the loss of cell-cell junctions and cell polarity, resulting in the acquisition of migratory and invasive properties. Recent evidence showed that altered microRNA-10b (miR-10b) expression was implicated in the occurrence of EMT of breast cancer. However, the exact role and underlying mechanisms of miR-10b in the EMT of breast cancer still remain unknown. In this study, miR-10b was found to be upregulated in breast cancer tissues and breast cancer cell lines and the expression of miR-10b was shown to be closely correlated with aggressiveness in breast cancer. Treating breast cancer cells with the miR-10b inhibitor increased E-cadherin expression while decreasing vimentin expression. At the same time, on inhibition of miR-10b, the invasion and proliferation ability of breast cancer cells also decreased. Transforming growth factor-β (TGF-β) is a multifunctional cytokine that induces EMT in multiple cell types. Here, we identified miR-10b as a target gene of TGF-β1. The expression of miR-10b increased during TGF-β1-induced EMT of breast cancer cells. Further study showed that inhibition of miR-10b expression partially reversed the EMT, invasion and proliferation induced by TGF-β1 in breast cancer cells. Taken together, these results demonstrated a novel function for miR-10b in TGF-β1-induced EMT in breast cancer and increased their metastatic potential. MiR-10b might become a possible target for gene therapy in breast cancer.

MicroRNA-regulated protein-protein interaction networks and their functions in breast cancer

MicroRNAs, which are small endogenous RNA regulators, have been associated with various types of cancer. Breast cancer is a major health threat for women worldwide. Many miRNAs were reported to be associated with the progression and carcinogenesis of breast cancer. In this study, we aimed to discover novel breast cancer-related miRNAs and to elucidate their functions. First, we identified confident miRNA-target pairs by combining data from miRNA target prediction databases and expression profiles of miRNA and mRNA. Then, miRNA-regulated protein interaction networks (PINs) were constructed with confident pairs and known interaction data in the human protein reference database (HPRD). Finally, the functions of miRNA-regulated PINs were elucidated by functional enrichment analysis. From the results, we identified some previously reported breast cancer-related miRNAs and functions of the PINs, e.g., miR-125b, miR-125a, miR-21, and miR-497. Some novel miRNAs without known association to breast cancer were also found, and the putative functions of their PINs were also elucidated. These include miR-139 and miR-383. Furthermore, we validated our results by receiver operating characteristic (ROC) curve analysis using our miRNA expression profile data, gene expression-based outcome for breast cancer online (GOBO) survival analysis, and a literature search. Our results may provide new insights for research in breast cancer-associated miRNAs.

MicroRNA-182 and microRNA-200a control G-protein subunit α-13 (GNA13) expression and cell invasion synergistically in prostate cancer cells

G protein-coupled receptors (GPCRs) and their ligands have been implicated in progression and metastasis of several cancers. GPCRs signal through heterotrimeric G proteins, and among the different types of G proteins, GNA12/13 have been most closely linked to tumor progression. In this study, we explored the role of GNA13 in prostate cancer cell invasion and the mechanism of up-regulation of GNA13 in these cells. An initial screen for GNA13 protein expression showed that GNA13 is highly expressed in the most aggressive cancer cell lines. Knockdown of GNA13 in highly invasive PC3 cells revealed that these cells depend on GNA13 expression for their invasion, migration, and Rho activation. As mRNA levels in these cells did not correlate with protein levels, we assessed the potential involvement of micro-RNAs (miRNAs) in post-transcriptional control of GNA13 expression. Expression analysis of miRNAs predicted to bind the 3'-UTR of GNA13 revealed that miR-182 and miR-141/200a showed an inverse correlation to the protein expression in LnCAP and PC3 cells. Ectopic expression of miR-182 and miR-141/200a in PC3 cells significantly reduced protein levels, GNA13-3'-UTR reporter activity and in vitro invasion of these cells. This effect was blocked by restoration of GNA13 expression in these cells. Importantly, inhibition of miR-182 and miR-141/200a in LnCAP cells using specific miRNA inhibitors elevated the expression of GNA13 and enhanced invasion of these cells. These data provide strong evidence that GNA13 is an important mediator of prostate cancer cell invasion, and that miR-182 and miR-200 family members regulate its expression post-transcriptionally.

Systemic administration of an antagomir designed to inhibit miR-92, a regulator of angiogenesis, failed to modulate skeletal anabolic response to mechanical loading

The goal of this study is to evaluate if promotion of angiogenesis by systemic treatment with an antagomir against miR-92a, a well established inhibitor of angiogenesis, will maximize the benefits of exercise on bone. Ten week old female C57BL6/J mice were subjected to two weeks of external load by four point bending. During the first week of mechanical loading (ML), mice were injected (2.7 mg/kg of bodyweight) with antagomir against miR-92 or control antagomir (3 alternate days via retro-orbital). No difference in tissues weights (heart, kidney, liver) were found in mice treated with miR-92 vs. control antagomir suggesting no side effects. Two weeks of ML increased tibia TV, BV/TV and density by 6-15 %, as expected, in the control antagomir treated mice. Similar increases in the above parameters (7-16 %) were also seen in mice treated miR-92 antagomir. Administration of miR-92 antagomir was effective in reducing levels of mir-92 in heart, liver and skeletal muscle and in contrast, expression levels of two other microRNA's miR-93 and miR-20a remain constant, thus suggesting specificity of the antagomir used. Surprisingly, we failed to detect significant changes in the expression levels of vascular genes (VEGF, CD31 and Tie2) in heart, liver or skeletal muscle. Based on these findings, we conclude that systemic administration of antagomir against miR-92 while reduced expression levels of miR-92 in the tissues; it did not significantly alter either angiogenic or osteogenic response, thus suggesting possible redundancy in miR-92 regulation of angiogenesis.

The bioinformatics analysis of miRNAs signatures differentially expressed in HER2(+) versus HER2(-) breast cancers

OBJECTIVE

To identify the signatures of miRNAs differentially expressed in HER2(+) versus HER2(-) breast cancers that accurately predict the HER2 status of breast cancer, and to provide further insight into breast cancer therapy.

METHODS

By the methods of literature search, aberrant expressed miRNAs were collected. By target prediction algorithm of TargetScan and PicTar and the data enrichment analysis, target gene sets of miRNAs differentially expressed in HER2(+) versus HER2(-) breast cancers were built. Then, using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) database, the function modules of Gene Ontology categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) and BIOCARTA pathway, biological functions and signaling pathways that are probably regulated by miRNAs, were analyzed.

RESULTS

We got five sets of miRNAs expressed in different HER2 status of breast cancers finally. The five sets of data contain 22; 32; 3; 38; and 62 miRNAs, respectively. After miRNAs target prediction and data enrichment, 5,734; 22,409; 1,142; 22,293; and 43,460 target genes of five miRNA sets were collected. Gene ontology analysis found these genes may be involved in transcription, protein transport, angiogenesis, and apoptosis. Moreover, certain KEGG and BIOCARTA signaling pathways related toHER2 status were found.

CONCLUSION

Using TargetScan and PicTar for data enrichment, and DAVID database, Gene Ontology categories, KEGG and BIOCARTA pathway for analysis of miRNAs different expression, we conducted a new method for biological interpretation of miRNA profiling data in HER2(+) versus HER2(-) breast cancers. It may improve understanding the regulatory roles of miRNAs in different molecular subtypes of breast cancers. Therefore, it is beneficial to improve the accuracy of experimental efforts to breast cancer and potential therapeutic targets.