Breast cancer and microRNAs: therapeutic impact

Mapping the function of MicroRNAs as a critical regulator of tumor-immune cell communication in breast cancer and potential treatment strategies

Among women, breast cancer ranks as the most prevalent form of cancer, and the presence of metastases significantly reduces prognosis and diminishes overall survival rates. Gaining insights into the biological mechanisms governing the conversion of cancer cells, their subsequent spread to other areas of the body, and the immune system's monitoring of tumor growth will contribute to the advancement of more efficient and targeted therapies. MicroRNAs (miRNAs) play a critical role in the interaction between tumor cells and immune cells, facilitating tumor cells' evasion of the immune system and promoting cancer progression. Additionally, miRNAs also influence metastasis formation, including the establishment of metastatic sites and the transformation of tumor cells into migratory phenotypes. Specifically, dysregulated expression of these genes has been associated with abnormal expression of oncogenes and tumor suppressor genes, thereby facilitating tumor development. This study aims to provide a concise overview of the significance and function of miRNAs in breast cancer, focusing on their involvement as tumor suppressors in the antitumor immune response and as oncogenes in metastasis formation. Furthermore, miRNAs hold tremendous potential as targets for gene therapy due to their ability to modulate specific pathways that can either promote or suppress carcinogenesis. This perspective highlights the latest strategies developed for miRNA-based therapies.

Non-Coding RNAs in Human Cancer and Other Diseases: Overview of the Diagnostic Potential

Non-coding RNAs (ncRNAs) are abundant single-stranded RNA molecules in human cells, involved in various cellular processes ranging from DNA replication and mRNA translation regulation to genome stability defense. MicroRNAs are multifunctional ncRNA molecules of 18-24 nt in length, involved in gene silencing through base-pair complementary binding to target mRNA transcripts. piwi-interacting RNAs are an animal-specific class of small ncRNAs sized 26-31 nt, responsible for the defense of genome stability via the epigenetic and post-transcriptional silencing of transposable elements. Long non-coding RNAs are ncRNA molecules defined as transcripts of more than 200 nucleotides, their function depending on localization, and varying from the regulation of cell differentiation and development to the regulation of telomere-specific heterochromatin modifications. The current review provides recent data on the several forms of small and long non-coding RNA's potential to act as diagnostic, prognostic or therapeutic target for various human diseases.

A Review of the Nucleic Acid-Based Lateral Flow Assay for Detection of Breast Cancer from Circulating Biomarkers at a Point-of-Care in Low Income Countries

The current levels of breast cancer in African women have contributed to the high mortality rates among them. In South Africa, the incidence of breast cancer is also on the rise due to changes in behavioural and biological risk factors. Such low survival rates can be attributed to the late diagnosis of the disease due to a lack of access and the high costs of the current diagnostic tools. Breast cancer is asymptomatic at early stages, which is the best time to detect it and intervene to prevent high mortality rates. Proper risk assessment, campaigns, and access to adequate healthcare need to be prioritised among patients at an early stage. Early detection of breast cancer can significantly improve the survival rate of breast cancer patients, since therapeutic strategies are more effective at this stage. Early detection of breast cancer can be achieved by developing devices that are simple, sensitive, low-cost, and employed at point-of-care (POC), especially in low-income countries (LICs). Nucleic-acid-based lateral flow assays (NABLFAs) that combine molecular detection with the immunochemical visualisation principles, have recently emerged as tools for disease diagnosis, even for low biomarker concentrations. Detection of circulating genetic biomarkers in non-invasively collected biological fluids with NABLFAs presents an appealing and suitable method for POC testing in resource-limited regions and/or LICs. Diagnosis of breast cancer at an early stage will improve the survival rates of the patients. This review covers the analysis of the current state of NABLFA technologies used in developing countries to reduce the scourge of breast cancer.

Exploring the Mechanism of Baicalin Intervention in Breast Cancer Based on MicroRNA Microarrays and Bioinformatics Strategies

Objective

To explore the mechanism of baicalin intervention in breast cancer based on microRNA microarrays.

Methods

The inhibitory rate of baicalin intervention in MCF-7 breast cancer cells was determined by MTT. Then, the miRNA microarrays were used to validate the key microRNAs. After that, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to validate microRNA, hsa-miR-15a, hsa-miR-100, hsa-miR-16, and hsa-miR-7t. Finally, the potential targets of these key microRNAs are predicted by miRWalk, and DAVID was utilized for gene ontology (GO) enrichment analysis and pathway enrichment analysis.

Results

Baicalin may inhibit the proliferation of MCF-7 cells in a dose-dependent and time-dependent manner. The concentration of baicalin 150 μmol/L was determined for the subsequent miRNA chip research. A total of 92 upregulated microRNAs and 35 downregulated microRNAs were obtained. The upregulated miRNAs include hsa-miR-6799-5p, hsa-miR-6126, hsa-miR-4792, hsa-miR-6848-5p, hsa-miR-3197, hsa-miR-6779-5p, and hsa-miR -654-5p. The downregulated miRNAs include hsa-miR-3911, hsa-miR-504-5p, hsa-miR-30a-3p, hsa-miR-193b-3p, and hsa-miR-181b-5p. Then, differentially expressed miRNA was verified by qRT-PCR. The results showed that the expression of hsa-miR-15a, hsa-miR-100, hsa-miR-16, and hsa-let-7c was upregulated (P < 0.05), which was consistent with the results of the miRNA microarray. The enrichment analysis showed that baicalin might regulate the DNA-templated proliferation, DNA-templated transcription, p53 signaling pathway, etc., of MCF-7 breast cancer cells through miRNA.

Conclusion

Baicalin inhibits the proliferation of breast cancer cells. It may achieve antitumor effects through regulating microRNAs so as to affect the DNA replication (such as cellular response to DNA damage stimulus and DNA binding), RNA transcription (such as regulation of transcription, DNA-templated, transcription from RNA polymerase II promoter, and transcription factor binding), protein synthesis (such as mRNA binding, Golgi apparatus, and protein complex), endocytosis, pathways in cancer, p53 signaling pathway, and so on.

miR-511-5p Suppresses Cell Migration, Invasion and Epithelial-Mesenchymal Transition Through Targeting PAK2 in Gastric Cancer

As a malignant tumor, gastric cancer (GC) is closely related with gastric mucosa and has a high mortality in the world. Since microRNA (miRNA) has become more and more important in tumor research, we intend to find out the functional role and mechanism of miR-511-5p in GC. Firstly, miR-511-5p level was examined in human GC cell lines and tissues, and its effect on cell migration and invasion of BGC-823 or HGC-27 cells was tested by migration assay and transwell assay. Then, we confirmed the association between miR-511-5p and p21 activated kinase 2 (PAK2) by the luciferase reporter assay, and further assessed their role in cell migration and invasion. Moreover, we verified the function of miR-511-5p and PAK2 in epithelial-mesenchymal transition (EMT). In our study, miR-511-5p was downregulated in GC cell lines and tissues, and inversely associated with PAK2. Luciferase reporter assay confirmed that miR-511-5p could bind to PAK2. MiR-511-5p mimics significantly upregulated E-cadherin and downregulated N-cadherin, Vimentin and Snail, and consequently inhibited cell migration and invasion. However, reintroduction of PAK2 reversed the inhibitory function of miR-511-5p on BGC-823 and HGC-27 cells. Our research suggested that tumor-suppressive function of miR-511-5p in GC was inhibited by PAK2, and miR-511-5p/PAK2 axis may serve as a new strategy in GC management.

Resistin Induces LIN28A-Mediated Let-7a Repression in Breast Cancer Cells Leading to IL-6 and STAT3 Upregulation

Simple Summary

Breast cancer is the second leading cause of cancer-related death in women in the United States and exhibits significant racial disparities in clinical outcomes. Earlier, we reported that the levels of resistin and IL-6 were significantly more elevated in the serum of African American women with breast cancer than in their Caucasian American counterparts. Here, we uncover its mechanistic significance by characterizing a novel resistin/LIN28A/Let-7a/IL-6/STAT3 signaling axis supporting the growth and stemness of breast cancer cells.

Abstract

Downregulation of the Let-7 family of microRNAs (miRNAs) has been reported in several cancers, including breast malignancy; however, underlying mechanisms are not completely understood. Resistin is an important component of the tumor microenvironment, having a functional impact on the tumor cell phenotypes. Here, we examined the role of resistin in the regulation of Let-7 miRNAs and studied its downstream consequences. We found that resistin treatment led to the reduced expression of Let-7 family miRNAs in breast cancer (BC) cells, with the highest downregulation reported for Let-7a. Furthermore, resistin induced the expression of LIN28A, and its silencing abrogated resistin-mediated Let-7a suppression. Let-7a restoration or LIN28A silencing abolished the resistin-induced growth, clonogenicity, and sphere-forming ability of BC cells. Restoration of Let-7a also suppressed the resistin-induced expression of genes associated with growth, survival, and stemness. Pathway analysis suggested STAT3 as a putative central node associated with Let-7a-mediated gene regulation. In silico analysis identified STAT3 and its upstream modifier, IL-6, as putative Let-7a gene targets, which were later confirmed by 3′UTR-reporter assays. Together, our findings demonstrate a novel resistin/LIN28A/Let-7a/IL-6/STAT3 signaling axis supporting the growth and stemness of BC cells.

Association between single-nucleotide polymorphisms in miRNA and breast cancer risk: an updated review

Breast cancer (BC), a heterogeneous, aggressive illness with high mortality, is essentially a genomic disease. While the high-penetrance genes BRCA1 and BRCA2 play important roles in tumorigenesis, moderate- and low-penetrance genes are also involved. Single-nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes have recently been identified as BC risk factors. miRNA genes are currently classified as low-penetrance. SNPs are the most common variations in the human genome. While the role of miRNA SNPs in BC susceptibility has been studied extensively, results have been inconsistent. This review analyzes the results of association studies between miRNA SNPs and BC risk from countries around the world. We conclude that: (a) By continent, the largest proportion of studies to date were conducted in Asia (65.0 %) and the smallest proportion in Africa (1.8 %); (b) Association studies have been completed for 67 different SNPs; (c) 146a, 196a2, 499, 27a, and 423 are the most-studied miRNAs; (d) The SNPs rs2910164 (miRNA-146a), rs11614913 (miRNA-196a2), rs3746444 (miRNA-499) and rs6505162 (miRNA-423) were the most widely associated with increased BC risk; (e) The majority of studies had small samples, which may affect the precision and power of the results; and (f) The effect of an SNP on BC risk depends on the ethnicity of the population. This review also discusses potential explanations for controversial findings.

Omics Multi-Layers Networks Provide Novel Mechanistic and Functional Insights Into Fat Storage and Lipid Metabolism in Poultry

Fatty acid metabolism in poultry has a major impact on production and disease resistance traits. According to the high rate of interactions between lipid metabolism and its regulating properties, a holistic approach is necessary. To study omics multilayers of adipose tissue and identification of genes and miRNAs involved in fat metabolism, storage and endocrine signaling pathways in two groups of broiler chickens with high and low abdominal fat, as well as high-throughput techniques, were used. The gene–miRNA interacting bipartite and metabolic-signaling networks were reconstructed using their interactions. In the analysis of microarray and RNA-Seq data, 1,835 genes were detected by comparing the identified genes with significant expression differences (p.adjust < 0.01, fold change ≥ 2 and ≤ −2). Then, by comparing between different data sets, 34 genes and 19 miRNAs were detected as common and main nodes. A literature mining approach was used, and seven genes were identified and added to the common gene set. Module finding revealed three important and functional modules, which were involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, biosynthesis of unsaturated fatty acids, Alzheimer’s disease metabolic pathway, adipocytokine, insulin, PI3K–Akt, mTOR, and AMPK signaling pathway. This approach revealed a new insight to better understand the biological processes associated with adipose tissue.

miR-221/222 sponge abrogates tamoxifen resistance in ER-positive breast cancer cells through restoring the expression of ERα

Tamoxifen resistance (TamR) prevents ER-positive breast cancer patients from benefitting from endocrine therapy, and miR-221 or miR-222 plays vital roles in inducing TamR. In this study, we designed synthetic sponges to reverse TamR by targeting these two miRs. First, we established a tamoxifen resistant breast cancer cell line (MCF-7^TamR), we verified the high expressing level of these two miRs in TamR cells. miR-221 or miR-222 inhibitors rendered MCF-7^TamR cells responsive to tamoxifen. Next, we designed a miR-221/222 sponge, which contains total 8 multi-antisense binding sites (MBSs) for these two onco-miRs, and inserted it into CMV promoter- or hTERT promoter-driven expressing vectors. After transfected miR-221/222 sponge expressing vectors into MCF-7^TamR cells, we identified a strong interaction between miR-221/222 sponge and endogenous miR-221 or miR-222 by RNA pulldown assay. We also found that miR-221/222 sponge restored the expression of ERα and PTEN, arrested cells in G1 phase, and finally resulted in reduced cell growth and cell migration. Notably, miR-221/222 sponge expressing cells abrogates tamoxifen resistance through restoring the expression of ERα, suggesting that miR-221/222 sponge gene therapy especially driven by tumor specific promoter could provide an effective therapeutic approach against TamR in breast cancer.

Genetic Association Analysis Implicates Six MicroRNA-Related SNPs With Increased Risk of Breast Cancer in Australian Caucasian Women

INTRODUCTION

Breast cancer (BC), a heterogeneous disease, features microRNA-related single nucleotide polymorphisms (miRSNPs) as underlying factors of BC development, thus providing targets for novel diagnostic and therapeutic strategies. This study investigated miRSNPs in BC susceptibility in Australian Caucasian women.

PATIENTS AND METHODS

The study population included patients 33 to 80 years of age stratified by molecular subtypes of breast tumors (luminal A, 47.59%), stage (stage I, 36.96%), tumor-type (ductal, 44.95%), grading (intermediate, 35.52%), size (10.1-25 mm, 31.14%), and lymph node (sentinel negative, 38.93%). Sixty-five miRSNPs underwent allelic analysis in two independent case-control cohorts (GU-CCQ-BB, 377 cases and 521 controls; GRC-BC, 267 cases and 201 controls) using a MassARRAY platform. GU-CCQ-BB, GRC-BC, and the combined populations (BC-CA) (644 cases and 722 controls) underwent independent statistical analysis.

RESULTS

In the GU-CCQ-BB population, miRSNPs TET2-rs7670522, ESR1-rs2046210, FGFR2-rs1219648, MIR210-rs1062099, HIF1A-rs2057482, and CASC16-rs4784227 were found to be associated with increased BC risk (P ≤ .05). Only ESR1-rs2046210 was also significantly associated (P ≤ .05) when replicated in the GRC-BC and BC-CA populations. No significant association was correlated with BC-clinical features (pathological types and ER/PR/HER2 status); however, MIR210-rs1062099 was found to be significantly associated (P ≤ .05) with age (>50 years) in the GU-CCQ-BB cohort.

CONCLUSION

This is the first study to demonstrate the association of MIR210-rs1062099 and TET2-rs7670522 with increased BC risk. Additionally, four previously reported SNPs (ESR1-rs2046210, FGFR2-rs1219648, HIF1A-rs2057482, and CASC16-rs4784227) were confirmed as BC risk variants. Replication and functional studies in larger Caucasian cohorts are necessary to elucidate the role of these miRSNPS in the development of BC.

MicroRNA: A signature for cancer progression

MicroRNAs (miRNAs) are a group of small non-coding RNAs that post-transcriptionally control expression of genes by targeting mRNAs. miRNA alterations partake in the establishment and progression of different types of human cancer. Consequently, expression profiling of miRNA in human cancers has correlations with cancer detection, staging, progression, and response to therapies. Particularly, amplification, deletion, abnormal pattern of epigenetic factors and the transcriptional factors that mediate regulation of primary miRNA frequently change the landscape of miRNA expression in cancer. Indeed, changes in the quantity and quality of miRNAs are associated with the initiation of cancer, its progression and metastasis. Additionally, miRNA profiling has been used to categorize genes that can affect oncogenic pathways in cancer. Here, we discuss several circulating miRNA signatures, their expression profiles in different types of cancer and their impacts on cellular processes.

Effect of miR-184 on Proliferation and Apoptosis of Pancreatic Ductal Adenocarcinoma and Its Mechanism

Objective:

Previous studies have shown that abnormal expression of microRNA-184 leads to a variety of cancers, including pancreatic ductal adenocarcinoma, suggesting microRNA-184 as a new treatment target for pancreatic ductal adenocarcinoma. However, the molecular mechanism of microRNA-184 in pancreatic ductal adenocarcinoma remains unclear. It is important to investigate the effect and role of microRNA-184 in pancreatic ductal adenocarcinoma.

Methods:

The clinical and laboratory inspection data of 120 patients with pancreatic cancer admitted to the First Affiliated Hospital of Anhui Medical University were compared. MicroRNA-184 expression in tumor tissues and cells was evaluated using reverse transcription polymerase chain reaction. Flow cytometry and Annexin V/propidium iodide staining were performed to examine cell cycle and apoptosis. Western blotting analysis was conducted to measure the protein expression of p-PI3K, p-AKT, JNK1, C-Myc, C-Jun, caspase-9, and caspase-3.

Results:

MicroRNA-184 expression was low in patients with pancreatic ductal adenocarcinoma. Survival curve showed that patients with lower expression of microRNA-184 in tumor tissues had a worse prognosis and shorter survival time (P < .05), and the multivariate analysis identified that microRNA-184 was an independent prognostic indicator (P < .05). In vitro studies showed that microRNA-184 overexpression induced apoptosis and suppressed cell cycle transition from G1 to S and G2 phases in pancreatic ductal adenocarcinoma cells. Furthermore, molecular studies revealed that inhibition of microRNA-184 promoted the gene expression of p-PI3K, p-AKT, JNK1, C-Myc, and C-Jun compared with the control group. Overexpression of microRNA-184 led to significantly increased expression of caspase-9 and caspase-3 and significantly decreased expression of Bcl-2.

Conclusion:

This study suggests that microRNA-184 inhibits the proliferation and promotes the apoptosis of pancreatic ductal adenocarcinoma cells by downregulating the expression of C-Myc, C-Jun, and Bcl-2. Our verification of the role of microRNA-184 may provide a novel biomarker for the diagnosis, therapy, and prognosis of pancreatic ductal adenocarcinoma.

MicroRNA-Dependent Targeting of RSU1 and the IPP Adhesion Complex Regulates the PTEN/PI3K/AKT Signaling Pathway in Breast Cancer Cell Lines

(1) Background: The microRNA (miR)-directed control of gene expression is correlated with numerous physiological processes as well as the pathological features of tumors. The focus of this study is on the role of miRs in the regulation of RSU1 and proteins in the IPP (integrin linked kinase, PINCH and parvin) complex. Because the IPP adaptor proteins link β integrins to actin cytoskeleton, and the RSU1 signaling protein connects the complex to the activation of cJun, ATF2 and the transcription of PTEN, their reduction by miRs has the potential to alter both adhesion and survival signaling. (2) Methods: Multiple database analyses were used to identify miRs that target RSU1 and PINCH1. miR transfection validated the effects of miRs on RSU1, PINCH1 and downstream targets in breast cancer cell lines. (3) Results: The miRs targeting RSU1 mRNA include miR-182-5p, -409-3p, -130a-3p, -221-3p, -744-5p and -106b-5p. Data show that miR-182-5p and -409-3p reduce RSU1, PINCH1 and inhibit the ATF2 activation of PTEN expression. miR-221-3p and miR-130a-3p target RSU1 and PINCH1 and, conversely, RSU1 depletion increases miR-221-3p and miR-130a-3p. (4) Conclusions: miRs targeting RSU1 and PINCH1 in mammary epithelial or luminal breast cancer cell lines reduced RSU1 signaling to p38 MAP kinase and ATF2, inhibiting the expression of PTEN. miR-221-3p, known to target PTEN and cell cycle regulators, also targets RSU1 and PINCH1 in luminal breast cancer cell lines.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

The Microrna-143/145 Cluster in Tumors: A Matter of Where and When

The establishment and spreading of cancer involve the acquirement of many biological functions including resistance to apoptosis, enhanced proliferation and the ability to invade the surrounding tissue, extravasate from the primary site, survive in circulating blood, and finally extravasate and colonize distant organs giving origin to metastatic lesions, the major cause of cancer deaths. Dramatic changes in the expression of protein coding genes due to altered transcription factors activity or to epigenetic modifications orchestrate these events, intertwining with a microRNA regulatory network that is often disrupted in cancer cells. microRNAs-143 and -145 represent puzzling players of this game, with apparently contradictory functions. They were at first classified as tumor suppressive due to their frequently reduced levels in tumors, correlating with cell survival, proliferation, and migration. More recently, pro-oncogenic roles of these microRNAs have been described, challenging their simplistic definition as merely tumor-suppressive. Here we review their known activities in tumors, whether oncogenic or onco-suppressive, and highlight how their expression and functions are strongly dependent on their complex regulation downstream and upstream of cytokines and growth factors, on the cell type of expression and on the specific tumor stage.

Targeting the miR-122/PKM2 autophagy axis relieves arsenic stress

Arsenic (As) is a natural hepatotoxicity inducer that is found ubiquitously in foods and environmental media. We found that arsenite exposure elicits autophagy in vivo and vitro, the specific role and regulatory mechanism of which are yet clear. MicroRNAs (miRNAs) are short noncoding RNAs that function in the posttranscriptional regulation of gene expression. Here, we report that miR-122, the most enriched constitutive miRNA in the liver, induced cell protective autophagy in arsenite-exposed hepatocytes. Arsenite exposure elevated miRNA-122 level and decreased the level of its target gene, PKM2. Under arsenic stress, overexpression of miR-122 significantly induced cell protective autophagy, characterized by lipidation of LC3-II and a corresponding consumption of p62. Conversely, autophagy inhibition by miR-122 knockdown was reversed by si-PKM2 cotransfection. We also found that miR-122 knockdown positively regulated the PI3K/Akt/mTOR pathway, and this phenomenon was reversed by cotransfecting cells with si-PKM2. Taken together, our findings show that the miR-122/PKM2 autophagy axis protects hepatocytes from arsenite stress via the PI3K/Akt/mTOR pathway; thus, miR-122 may be a potential candidate in the treatment of arseniasis.

Aberrant expression of a five-microRNA signature in breast carcinoma as a promising biomarker for diagnosis

BACKGROUND

Breast cancer (BC) is the most common malignancy among females with dismal quality of life in patients. It has been proven that epigenetic factors, especially microRNAs, are involved in breast carcinogenesis and progression. This study aimed to assess the expression and clinical performances of a five-microRNA signature (miR-127-3p, miR-133a-3p, miR-155-5p, miR-199b-5p, and miR-342-5p) in breast cancer and adjacent normal tissues to identify a potential biomarker for BC and investigate the relationship between their expression and clinicopathological features of BC patients as well.

METHODS

In this case-control investigation, we recruited 50 pairs of tumor and matched non-tumor surgical specimens from patients diagnosed with BC. Expression levels of miR-127-3p, miR-133a-3p, miR-155-5p, miR-199b-5p, and miR-342-5p were measured in BC and adjacent normal tissues by RT-qPCR.

RESULTS

We found that miR-127-3p, miR-133a-3p, miR-199b-5p, and miR-342-5p were significantly down-regulated, while miR-155-5p was significantly up-regulated in BC tumor tissues compared with the corresponding adjacent normal tissues. The decreased expression of miR-127-3p, miR-133a-3p, miR-342-5p, and up-regulation of miR-155-5p showed a significant correlation with disease stage. We also found a significant down-regulation of miR-127-3p, miR-199b-5p, and miR-342-5p compared in HER-2-negative patients. Our results indicated that miR-155-5p had a higher expression level in HER-2-positive patients. Receiver operating characteristic (ROC) curve analysis demonstrated that all these five microRNAs can serve as potential biomarkers to distinguish between tumor and non-tumor breast tissue samples.

CONCLUSIONS

The present findings suggested that dysregulation of this five-miRNA signature might be considered as a promising and functional biomarker for BC diagnosis.

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.

An insight of microRNAs performance in carcinogenesis and tumorigenesis; an overview of cancer therapy

Importance of dysregulation and expression of microRNAs (miRNAs) has been confiemed in many disorders comprising cancer. In this way, different approaches to induce reprogramming from one cell type to another in oerder to control the cell normal mechanisem, comprising microRNAs, combinatorial small molecules, exosome-mediated reprogramming, embryonic microenvironment and also lineage-specific transcription agents, are involved in cell situation. Meaningly, besides the above factors, microRNAs are so special and have an impressive role in cell reprogramming. One of the main applications of cancer cell reprogramming is it's ability in therapeutic approach. Many insights in reprogramming mechanism have been recommended, and determining improvment has been aknolwged to develop reprogramming efficiency and possibility, permiting it to appear as practical therapy against all cancers. Conspiciously, the recent studies on the fluctuations and performance of microRNAs,small endogenous non-coding RNAs, as notable factors in carcinogenesis and tumorigenesis, therapy resistance and metastasis and as new non-invasive cancer biomarkers has a remarkable attention. This is due to their unique dysregulated signatures throughout tumor progression. Recognising miRNAs signatures capable of anticipating therapy response and metastatic onset in cancers might enhance diagnosis and therapy. According to the growing reports on miRNAs as novel non-invasive biomarkers in various cancers as a main regulators of cancers drug resistance or metastasis, the quest on whether some miRNAs have the ability to regulate both simultaneously is inevitable, yet understudied. The combination of genetic diagnosis using next generation sequencing and targeted therapy may contribute to the effective precision medicine for cancer therapy. Here, we want to review the practical application of microRNAs performance in carcinogenesis and tumorigenesis in cancer therapy.

MicroRNA and Oxidative Stress Interplay in the Context of Breast Cancer Pathogenesis

Oxidative stress is a pathological condition determined by a disturbance in reactive oxygen species (ROS) homeostasis. Depending on the entity of the perturbation, normal cells can either restore equilibrium or activate pathways of cell death. On the contrary, cancer cells exploit this phenomenon to sustain a proliferative and aggressive phenotype. In fact, ROS overproduction or their reduced disposal influence all hallmarks of cancer, from genome instability to cell metabolism, angiogenesis, invasion and metastasis. A persistent state of oxidative stress can even initiate tumorigenesis. MicroRNAs (miRNAs) are small non coding RNAs with regulatory functions, which expression has been extensively proven to be dysregulated in cancer. Intuitively, miRNA transcription and biogenesis are affected by the oxidative status of the cell and, in some instances, they participate in defining it. Indeed, it is widely reported the role of miRNAs in regulating numerous factors involved in the ROS signaling pathways. Given that miRNA function and modulation relies on cell type or tumor, in order to delineate a clearer and more exhaustive picture, in this review we present a comprehensive overview of the literature concerning how miRNAs and ROS signaling interplay affects breast cancer progression.

The role of microRNA-608 polymorphism on the susceptibility and survival of cancer: a meta-analysis

The role of rs4919510 polymorphism in microRNA-608 (miR-608) and cancer susceptibility and prognosis remain controversial and debatable. We conducted a meta-analysis of twenty-four eligible publications on the association of rs4919510 polymorphism with cancer risk and/or prognosis. Odds ratios, hazard ratios, and 95% confidence interval were used to investigate the association between this polymorphism and susceptibility, overall survival, and recurrence-free survival of cancer. Overall, eighteen case-control studies and nine cohort studies evaluated the susceptibility and prognostic value of rs4919510 polymorphism in cancer, respectively. Pooled analysis showed that rs4919510 polymorphism was not associated with cancer risk in all five genetic models. When stratifying by different cancer sites, rs4919510 polymorphism was detected to have a significant association with a decreased risk of colorectal cancer in homozygous model (P = 0.006) and recessive model (P = 0.001), subgroup analysis also emerged a weakened correlation between rs4919510 polymorphism and an increased risk of papillary thyroid cancer in heterozygote model (P = 0.04). Furthermore, the prognosis of rs4919510 variant in cancer patients showed that rs4919510 GG genotype was significant association with poor recurrence-free survival in homozygous models (P = 0.04). The meta-analysis suggested that the microRNA-608 rs4919510 polymorphism maybe associate with a significantly decreased risk for colorectal cancer. Further investigations on larger populations are required to evaluate and confirm this relationship.

Role of miR-10b-5p in the prognosis of breast cancer

Breast cancer is the leading cause of cancer-related death in women worldwide. Aberrant expression levels of miR-10b-5p in breast cancer has been reported while the molecular mechanism of miR-10b-5p in tumorigenesis remains elusive. Therefore, this study was aimed to investigate the role of miR-10b-5p in breast cancer and the network of its target genes using bioinformatics analysis. In this study, the expression profiles and prognostic value of miR-10b-5p in breast cancer were analyzed from public databases. Association between miR-10b-5p and clinicopathological parameters were analyzed by non-parametric test. Moreover, the optimal target genes of miR-10b-5p were obtained and their expression patterns were examined using starBase and HPA database. Additionally, the role of these target genes in cancer development were explored via Cancer Hallmarks Analytics Tool (CHAT). The protein–protein interaction (PPI) networks were constructed to further investigate the interactive relationships among these genes. Furthermore, GO, KEGG pathway and Reactome pathway analyses were carried out to decipher functions of these target genes. Results demonstrated that miR-10b-5p was down-regulated in breast cancer and low expression of miR-10b-5p was significantly correlated to worse outcome. Five genes, BIRC5, E2F2, KIF2C, FOXM1, and MCM5, were considered as potential key target genes of miR-10b-5p. As expected, higher expression levels of these genes were observed in breast cancer tissues than in normal tissues. Moreover, analysis from CHAT revealed that these genes were mainly involved in sustaining proliferative signaling in cancer development. In addition, PPI networks analysis revealed strong interactions between target genes. GO, KEGG, and Reactome pathway analysis suggested that these target genes of miR-10b-5p in breast cancer were significantly involved in cell cycle. Predicted target genes were further validated by qRT-PCR analysis in human breast cancer cell line MDA-MB-231 transfected with miR-10b mimic or antisense inhibitors. Taken together, our data suggest that miR-10b-5p functions to impede breast carcinoma progression via regulation of its key target genes and hopefully serves as a potential diagnostic and prognostic marker for breast cancer.

Synthesis of Nano-Paramagnetic Oleuropein to Induce KRAS Over-Expression: A New Mechanism to Inhibit AGS Cancer Cells

Background and objectives: Human gastric adenocarcinoma (AGS) is one of the most common malignant cancers worldwide. The present study aimed to transfer oleuropein into cancer cells using synthetic paramagnetic nanoparticles and study their effect on the AGS (ATCC^® CRL1739™) cell line. Materials and Methods: Paramagnetic nano-oleuropein was synthesized using four-stage co-precipitation by developing NH-connected bridges and was evaluated by EDS, SEM and FTIR methods. Different concentrations of magnetic oleuropein (0, 0.15, 0.45, 1.37, 4.12, 12.35, 37.04, 111.11, 333.33, 1000 µg/mL) were used to treat the AGS cell line in a completely randomized design using a statistical framework with three replicates. The relative expression rate of miR-200 and KRAS oncogenes was evaluated using real-time PCR. The inhibition rate of the AGS cells was assessed using the MTT test at 24, 48 and 72 h intervals. Results: The results showed that there was a significant difference between the inhibition rates of magnetic nano-oleuropein at IC50-24h (23.6 µg/mL), IC50-48h (15.2 µg/mL) and IC50-72h (9.2 µg/mL). Real-time PCR indicated that the relative expression of KRAS and miR-200 genes was highest at IC50 at these intervals. Conclusions: Magnetic nano-oleuropein can be subjected to objective testing and clinical evaluations as a natural antioxidant to prevent and treat gastric adenocarcinoma.

miR-148b-3p, miR-190b, and miR-429 Regulate Cell Progression and Act as Potential Biomarkers for Breast Cancer

Purpose

Breast cancer is the most frequently diagnosed malignancy in women worldwide. MicroRNAs (miRNAs) are thought to serve as potential biomarkers in various cancers, including breast cancer.

Methods

We evaluated the miRNA expression profiles in 1,083 breast cancer samples and 104 normal breast tissues from The Cancer Genome Atlas database. We used the edgeR package of R software to analyze the differentially expressed miRNAs in normal and cancer tissues, and screened survival-related miRNAs by Kaplan-Meier analysis. A receiver operating characteristic curve was generated to evaluate the accuracy of these miRNAs as molecular markers for breast cancer diagnosis. Furthermore, the functional role of these miRNAs was verified using cell experiments. Targets of candidate miRNAs were predicted using 9 online databases, and Gene Ontology (GO) functional annotation and pathway analyses were conducted using Database for Annotation, Visualization and Integrated Discovery online tool.

Results

A total of 68 miRNAs showed significantly different expression patterns between the groups (p < 0.001), and 13 of these miRNAs were significantly associated with poor survival (p < 0.05). Three miRNAs with high specificity and sensitivity, namely, miR-148b-3p, miR-190b, and miR-429, were selected. In vitro experiments showed that the overexpression of these 3 miRNAs significantly promoted the proliferation and migration of MDA-MB-468 and T47D cells and reduced the apoptosis of T47D cells. GO and pathway enrichment analyses revealed that the targets of these dysregulated miRNAs were involved in many critical cancer-related biological processes and pathways.

Conclusion

The miR-148b-3p, miR-190b, and miR-429 may serve as potential diagnostic and prognostic markers for breast cancer. This study demonstrated the roles of these 3 miRNAs in the initiation and progression of breast cancer.

miR-193: A new weapon against cancer

microRNAs (miRNAs) are known as a large group of short noncoding RNAs, which structurally consist of 19-22 nucleotides in length and functionally act as one of the main regulators of gene expression in important biological and physiological contexts like cell growth, apoptosis, proliferation, differentiation, movement (cell motility), and angiogenesis as well as disease formation and progression importantly in cancer cell invasion, migration, and metastasis. Among these notable tiny molecules, many studies recently presented the important role of the miR-193 family comprising miR-193a-3p, miR-193a-5p, miR-193b-3p, and miR-193b-5p in health and disease biological processes by interaction with special targeting and signaling, which mainly contribute as a tumor suppressor. Therefore, in the present paper, we review the functional role of this miRNA family in both health and disease conditions focusing on various tumor developments, diagnoses, prognoses, and treatment.

Epigenetics of Breast Cancer: Clinical Status of Epi-drugs and Phytochemicals

Epigenetics refers to alterations in gene expression due to differential histone modifications and DNA methylation at promoter sites of genes. Epigenetic alterations are reversible and are heritable during somatic cell division, but do not involve changes in nucleotide sequence. Epigenetic regulation plays a critical role in normal growth and embryonic development by controlling transcriptional activities of several genes. In last two decades, these modifications have been well recognized to be involved in tumor initiation and progression, which has motivated many investigators to incorporate this novel field in cancer drug development. Recently, growing number of epigenetic changes have been reported that are involved in the regulations of genes involved in breast tumor growth and metastasis. Drugs possessing epigenetic modulatory activities known as epi-drugs, mainly the inhibitors of histone deacetylases (HDACs) and DNA methyltransferases (DNMTs). Some of these drugs are undergoing different clinical trials for breast cancer treatment. Several phytochemicals such as green tea polyphenols, curcumin, genistein, resveratrol and sulforaphane have also been shown to alter epigenetic modifications in multiple cancer types including breast cancer. In this chapter, we summarize the role of epigenetic changes in breast cancer progression and metastasis. We have also discussed about various epigenetic modulators possessing chemopreventive and therapeutic efficacy against breast cancer with future perspectives.

Up-regulation of HOXB cluster genes are epigenetically regulated in tamoxifen-resistant MCF7 breast cancer cells

Tamoxifen (TAM) is commonly used to treat estrogen receptor (ER)-positive breast cancer. Despite the remarkable benefits, resistance to TAM presents a serious therapeutic challenge. Since several HOX transcription factors have been proposed as strong candidates in the development of resistance to TAM therapy in breast cancer, we generated an in vitro model of acquired TAM resistance using ER-positive MCF7 breast cancer cells (MCF7-TAMR), and analyzed the expression pattern and epigenetic states of HOX genes. HOXB cluster genes were uniquely up-regulated in MCF7-TAMR cells. Survival analysis of in slico data showed the correlation of high expression of HOXB genes with poor response to TAM in ER-positive breast cancer patients treated with TAM. Gain- and loss-of-function experiments showed that the overexpression of multi HOXB genes in MCF7 renders cancer cells more resistant to TAM, whereas the knockdown restores TAM sensitivity. Furthermore, activation of HOXB genes in MCF7-TAMR was associated with histone modifications, particularly the gain of H3K9ac. These findings imply that the activation of HOXB genes mediate the development of TAM resistance, and represent a target for development of new strategies to prevent or reverse TAM resistance.

Relative miRNA and mRNA expression involved in arsenic methylation

Three arsenic species in urine are measured using an atomic absorption spectrophotometer. RT-PCR is performed to detect the expression levels of AS3MT, 3 miRNAs, and 17 relative mRNAs in 43 workers producing arsenic trioxide, 36 workers who stopped exposure to arsenic for 85 days, and 24 individuals as the control group. The concentrations of urinary arsenic are very high in workers. A negative correlation between AS3MT and MiR-548c-3p is found. There exist significant changes for most selected miRNAs and mRNAs in workers. There are no significant differences between workers who stopped exposure to arsenic and the control group for most miRNAs and mRNAs, but the MiR-548c-3p levels show significant changes. Similar positive correlations between the expression of AS3MT and all selected mRNAs are found. Negative correlations between the expression of MiR-548c-3p and many relative mRNAs are found as well. AS3MT and MiR-548c-3p may regulate arsenic methylation jointly, which when involved in a group of relative mRNAs may play roles in arsenic metabolism and epigenetic changes caused by this metabolism.

Role of miR-142 in the pathogenesis of osteosarcoma and its potential as therapeutic approach

Osteosarcoma (OS) is the most common primary malignant tumor of the bone with a strong tendency to early metastasis, and occurs in growing bones more commonly in children and adolescents. Considering the limited therapeutic methods and lack of 100% success of these methods, developing innovative therapies with high efficacy and lower side effects is needed. Meanwhile, miRNAs and the studies indicating the involvement of miRNAs in OS development have attracted attentions as a result of the frequent abnormalities in expression of miRNAs in cancer. miRNAs are noncoding short sequences with lengths ranging from 18 to 25 nucleotides that play a very important role in cellular processes, such as proliferation, differentiation, migration, and apoptosis. MiRNAs can have either oncogenic or tumor suppressive role based on cellular function and targets. This review aimed to have overview on miR-142 as a tumor suppressor in OS. Moreover, the genes involved in the disease, such as RAC1, HMAG1, MMP9, MMP2, and E-cadherin, which have irregularities as a result of change in miR-142 expression, and, thereby, result in increasing the proliferation, invasion, and metastasis of the cells in the tissues and OS cells will be discussed.

Let-7b inhibits cancer-promoting effects of breast cancer-associated fibroblasts through IL-8 repression

Cancer-associated fibroblasts (CAFs) are major players in the development and spread of breast carcinomas through non-cell-autonomous signaling. These paracrine effects are under the control of several genes and microRNAs. We present here clear evidence that let-7b, a tumor suppressor microRNA, plays key roles in the persistent activation of breast stromal fibroblasts and their functional interplay with cancer cells. We have first shown that let-7b is down-regulated in CAFs as compared to their corresponding normal adjacent fibroblasts, and transient specific let-7b inhibition permanently activated breast fibroblasts through induction of the IL-6-related positive feedback loop. More importantly, let-7b-deficient cells promoted the epithelial-to-mesenchymal transition process in breast cancer cells in an IL-8-dependent manner, and also enhanced orthotopic tumor growth in vivo. On the other hand, overexpression of let-7b by mimic permanently suppressed breast myofibroblasts through blocking the positive feedback loop, which inhibited their paracrine pro-carcinogenic effects. Furthermore, we have shown that let-7b negatively controls IL-8, which showed higher expression in the majority of CAF cells as compared to their adjacent normal counterparts, indicating that IL-8 plays a major role in the carcinoma/stroma cross-talk. These findings support targeting active stromal fibroblasts through restoration of let-7b/IL-8 expression as a therapeutic option for breast carcinomas.

MicroRNA-588 is downregulated and may have prognostic and functional roles in human breast cancer

Background

We explored the expression pattern, prognostic potential, and functional role of microRNA-588 (miR-588) in human breast cancer (BC).

Material/Methods

The expression pattern of miR-588 was assessed by qPCR in BC cell lines and human BC carcinomas. The correlations between miR-588 and BC patients’ clinicopathological characteristics, as well as BC patients’ overall survival, were statistically assessed. In in vitro culture, MCF-7 and MDA-MB-231 cells were infected with lentivirus to overexpress endogenous miR-588. The subsequent effects of miR-588 upregulation on BC cell proliferation and cisplatin chemosensitivity were examined.

Results

miR-588 was found to be significantly downregulated in both BC cell lines and carcinoma tissues of BC patients. Low expression of miR-588 was closely correlated with BC patients’ poor prognosis of TNM stage, lymph node metastasis, and estrogen receptor status. In addition, patients with low miR-588-expressing carcinomas had much shorter overall survival. In MCF-7 and MDA-MB-231 cells, lentiviral infection induced significant miR-588 upregulation, and miR-588 upregulation had an anti-tumor effect in BC cells by significantly inhibiting cancer proliferation and increasing cisplatin chemosensitivity.

Conclusions

miR-588 is downregulated in BC and its aberrant expression is closely associated with patients’ poor prognosis and overall survival, thus suggesting a biomarker role. miR-588 also has anti-tumor function in BC, making it a potential therapeutic target for BC treatment.

MiR-155 inhibits proliferation and invasion by directly targeting PDCD4 in non-small cell lung cancer

Background

MicroRNAs are often abnormally expressed in human non‐small cell lung cancer (NSCLC) and are thought to play a critical role in the emergence or maintenance of NSCLC by binding to its target messenger RNA. We assessed the effects of miR‐155 on cell proliferation and invasion to elucidate the role played by miR‐155/PDCD4 in NSCLC.

Methods

Quantitative reverse transcription‐PCR, Western blotting, and cell counting kit‐8, luciferase, and transwell invasion assays were conducted on a normal human bronchial epithelial cell line (BEAS‐2B) and three NSCLC cell lines (SPC‐A‐1, A549, and H2170).

Results

We confirmed that miR‐155 was upregulated, while PDCD4 messenger RNA and protein levels were downregulated in NSCLC cell lines. miR‐155 negatively regulated PDCD4 at both transcriptional and post‐transcriptional levels. Moreover, PDCD4 was forecast as an assumed target of miR‐155 using bioinformatic methods and we demonstrated that PDCD4 was a direct target of miR‐155 using luciferase reporter assays. Furthermore, PDCD4 overexpression could restrain NSCLC proliferation and invasion induced by miR‐155.

Conclusion

Our results collectively demonstrate that miR‐155 exerts an oncogenic role in NSCLC by directly targeting PDCD4.

HER2 positivity may confer resistance to therapy with paclitaxel in breast cancer cell lines

INTRODUCTION

MicroRNAs (miRNAs) are short non-coding single-stranded RNAs. Involving in post-transcriptional gene silencing, miRNAs are thought to play important roles in many cancers such as breast cancer. Paclitaxel is used widely in the treatment of breast cancer. In this study, we investigated the effect of paclitaxel treatment on the expression levels of two oncomirs (oncomiRs), miR-21 and miR-203, in breast cancer cell lines.

MATERIALS AND METHODS

MTT assay was performed to determine IC50 of paclitaxel for human breast cancer cell lines including MCF-7, MDA-MB-231, SKBR3 and BT-474. After RNA extraction and cDNA synthesis, the expression levels of miRNAs were then quantitatively evaluated using real-time PCR.

RESULTS

Our results showed that after treatment, the expression levels of both miR-21 and miR-203 were significantly increased in HER2-positive cell lines, BT-474 and SKBR3. HER2-negative cell lines, MCF-7 and MDA-MB-231, in contrast had significantly decreased expression of both assessed oncomiRs.

CONCLUSION

Our results showed that the expression levels of oncomiRs were increased in HER-2 positive breast cancer cells and this finding is in line with previous studies. Our findings present a probable mechanism of resistance against paclitaxel chemotherapy in HER2-positive breast cancers.

Targeting Intracellular Calcium Signaling ([Ca2+]i) to Overcome Acquired Multidrug Resistance of Cancer Cells: A Mini-Overview

Cancer is a main public health problem all over the world. It affects millions of humans no matter their age, gender, education, or social status. Although chemotherapy is the main strategy for the treatment of cancer, a major problem limiting its success is the intrinsic or acquired drug resistance. Therefore, cancer drug resistance is a major impediment in medical oncology resulting in a failure of a successful cancer treatment. This mini-overview focuses on the interdependent relationship between intracellular calcium ([Ca²⁺]_i) signaling and multidrug resistance of cancer cells, acquired upon treatment of tumors with anticancer drugs. We propose that [Ca²⁺]_i signaling modulates gene expression of multidrug resistant (MDR) genes which in turn can be modulated by epigenetic factors which in turn leads to modified protein expression in drug resistant tumor cells. A precise knowledge of these mechanisms will help to develop new therapeutic strategies for drug resistant tumors and will improve current chemotherapy.

Downregulation of miRNA-141 in breast cancer cells is associated with cell migration and invasion: involvement of ANP32E targeting

MicroRNAs (miRNAs) regulate many cellular activities, including cancer development, progression, and metastasis. Some miRNAs are involved in breast cancer (BC) migration and invasion, thus affect patients’ prognosis. Microarray analysis was performed to compare miRNA expression in BC tissues, and results confirmed by qPCR. BC cell migration and invasion were studied in vitro with MDA‐MB‐231 cells using microplate transwell assays. miRNA targeting was investigated using luciferase assays, qPCR, and Western blot analysis in cells with overexpression of miRNA mimics. Knockdown of miRNA targets was performed using target siRNA lentiviral infection. Results show that microRNA‐141 (miR‐141) was downregulated in breast cancer tumor tissues compared with matched surrounding tissues. Downregulation of miR‐141 expression correlated with tumor stage, lymph node involvement, and expressions of PCNA, Ki67, and HER2. Overexpression of miR‐141 inhibited BC cell proliferation, migration, and invasion in vitro. ANP32E gene was selected as one putative target for further studies based on results from in silico analysis. Results from a dual‐luciferase reporter system suggested ANP32E as a direct target of miR‐141. Overexpression of miR‐141 downregulated ANP32E expression at both mRNA and protein levels in BC cells. Knockdown of ANP32E inhibited BC cell proliferation, migration, and invasion in vitro, mimicking the effect of the overexpression of miR‐141. Our study revealed important roles miR‐141 plays in BC growth and metastasis. Moreover, for the first time, we identified ANP32E as one of the miR‐141 targets, and demonstrated its involvement in the regulation of cell proliferation, migration, and invasion.

Computational study of 'HUB' microRNA in human cardiac diseases

MicroRNAs (miRNAs) are small non-coding RNAs ~22 nucleotides long that do not encode for proteins but have been reported to influence gene expression in normal and abnormal health conditions. Though a large body of scientific literature on miRNAs exists, their network level profile linking molecules with their corresponding phenotypes, is less explored. Here, we studied a network of 191 human miRNAs reported to play a role in 30 human cardiac diseases. Our aim was to study miRNA network properties like hubness and preferred associations, using data mining, network graph theory and statistical analysis. A total of 16 miRNAs were found to have a disease node connectivity of >5 edges (i.e., they were linked to more than 5 diseases) and were considered hubs in the miRNAcardiac disease network. Alternatively, when diseases were considered as hubs, >10 of miRNAs showed up on each ‘disease hub node’. Of all the miRNAs associated with diseases, 19 miRNAs (19/24= 79.1% of upregulated events) were found to be upregulated in atherosclerosis. The data suggest micro RNAs as early stage biological markers in cardiac conditions with potential towards microRNA based therapeutics.

Breast cancer-secreted miR-939 downregulates VE-cadherin and destroys the barrier function of endothelial monolayers

Exosomes-secreted microRNAs play an important role in metastatic spread. During this process breast cancer cells acquire the ability to transmigrate through blood vessels by inducing changes in the endothelial barrier. We focused on miR-939 that is predicted to target VE-cadherin, a component of adherens junction involved in vessel permeability. By in silico analysis miR-939 was found highly expressed in the basal-like tumor subtypes and in our cohort of 63 triple-negative breast cancers (TNBCs) its expression significantly interacted with lymph node status in predicting disease-free survival probability. We demonstrated, in vitro, that miR-939 directly targets VE-cadherin leading to an increase in HUVECs monolayer permeability. MDA-MB-231 cells transfected with a miR-939 mimic, released miR-939 in exosomes that, once internalized in endothelial cells, favored trans-endothelial migration of MDA-MB-231-GFP cells by the disruption of the endothelial barrier. Notably, when up taken in endothelial cells exosomes caused VE-cadherin down-regulation specifically through miR-939 as we demonstrated by inhibiting miR-939 expression in exosomes-releasing TNBC cells. Together, our data indentify an extracellular pro-tumorigenic role for tumor-derived, exosome-associated miR-939 that can explain its association with worse prognosis in TNBCs.

The pharmacoepigenetics of drug metabolism and transport in breast cancer: review of the literature and in silico analysis

The focus of this manuscript is on DNA methylation and miRNA regulation of drug-metabolizing enzymes and drug transporters involved in the disposition of drugs commonly used in breast cancer. We start with a review of the available scant literature and follow with an in silico analysis of the CpG islands and miRNA binding sites of genes of interest. We make the case that there is room for further research to include more genes and miRNAs despite the extensive sharing of miRNA targets by candidate genes of interest. We also stress on the role of peripheral blood as a source of pharmacoepigenetic biomarkers, and point out the lack of toxicoepigenetic studies in breast cancer.

Positive expression of miR-361-5p indicates better prognosis for breast cancer patients

BACKGROUND

MicroRNA-361-5p (miR-361-5p) has been reported to be tumor suppressor in colorectal, gastric and prostate cancer, but as an oncogene in cervical cancer. No previous research has focused on the expression of miR-361-5p and its exact prognostic role in breast cancer (BC).

METHODS

In this study, a tissue microarray (TMA)-based miRNA detection in situ hybridization (ISH) with LNA probe was used to detect miR-361-5p expression in 375 BC tissue. The expression level of miR-361-5p in BC and its potential prognostic value was investigated.

RESULTS

Positive miR-361-5p staining was observed in 78.7% (N=295; 78.7% positive, 21.3% negative) in the 375 cases. The clinical outcome of patients with positive miR-361-5p expression [median disease-free survival (DFS) time 95.52 months] was significantly better than that of patients (median DFS time 82.33 months) with negative miR-361-5p expression (P=0.002). Moreover, the prognostic value of miR-361-5p was most significant among patients with triple-negative breast cancer (TNBC) for DFS (P=0.004).

CONCLUSIONS

These results indicated that miR-361-5p expression is an independent predictive factor for better prognosis in BC.

MiRNA-183-5p promotes cell proliferation and inhibits apoptosis in human breast cancer by targeting the PDCD4

MicroRNAs are often aberrantly expressed in breast cancer and postulated to play a causal role in the onset and maintenance of breast cancer by binding to its target mRNA. Here, we evaluated the effects of miRNA-183-5p on cell proliferation and apoptosis which attempted to elucidate the potential role of miR-183-5p/PDCD4 axis in human breast cancer. We found that the miR-183-5p expression level was extremely promoted in breast cancer in comparison with the adjacent normal tissues. Overexpression of miR-183-5p significantly enhanced the cell proliferation and inhibited cell apoptosis in MCF-7 and MDA-MB-231 cells. Moreover, PDCD4 was predicted as a putative target of miR-183-5p by bioinformatic approaches, and miR-183-5p negatively regulated the expression of PDCD4. Furthermore, knockdown of PDCD4 suppressed expression of p21 and p27, which was consistent with the result of the attachment of miR-183-5p. These data collectively demonstrate that miR-183-5p exerts oncomiRs effects in breast cancer, and may have broad impacts on the field of using antimiRs as anti-cancer drugs for breast cancer.

Aberrant Expression of Breast Development-Related MicroRNAs, miR-22, miR-132, and miR-212, in Breast Tumor Tissues

PURPOSE

MicroRNAs (miRNAs) are a major class of small endogenous RNA molecules that posttranscriptionally regulate the expression of most genes in the human genome. miRNAs are often located in chromosomal fragile sites, which are suscept-ible to amplification or deletion. Chromosomal deletions are frequent events in breast cancer cells. Deletion and loss of heterozygosity at 17p13.3 have been reported in 49% of breast cancers. The aim of the current study was to evaluate potential expression alterations of miR-22, miR-132, and miR-212, which are located on the 17p13.3 locus and are required for mammary gland development.

METHODS

A matched case-control study was conducted, which included 36 pairs of tumor and matched nontumor surgical specimens from patients diagnosed with breast invasive ductal carcinoma. Formalin-fixed paraffin-embedded samples from archival collections at the pathology department of Shariati Hospital were prepared for RNA extraction using the xylene-ethanol method before total RNA was isolated with TRIzol Reagent. Specific primers were designed for cDNA synthesis and miRNA amplification. The expression of miRNAs was then evaluated by real-time polymerase chain reaction (RT-PCR).

RESULTS

According to our RT-PCR data, the miR-212/miR-132 family was downregulated in breast cancer (0.328-fold, p<0.001), and this reduced expression was the most prominent in high-grade tumors. In contrast, miR-22 exhibited a significant upregulation in breast tumor samples (2.183-fold, p=0.040).

CONCLUSION

Consistent with the frequent deletion of the 17p13.3 locus in breast tumor cells, our gene expression data demonstrated a significant downregulation of miR-212 and miR-132 in breast cancer tissues. In contrast, we observed a significant upregulation of miR-22 in breast tumor samples. The latter conflicting result may have been due to the upregulation of miR-22 in stromal/cancer-associated fibroblasts, rather than in the tumor cells.

A Set of miRNAs, Their Gene and Protein Targets and Stromal Genes Distinguish Early from Late Onset ER Positive Breast Cancer

Breast cancer (BC) in young adult patients (YA) has a more aggressive biological behavior and is associated with a worse prognosis than BC arising in middle aged patients (MA). We proposed that differentially expressed miRNAs could regulate genes and proteins underlying aggressive phenotypes of breast tumors in YA patients when compared to those arising in MA patients.

OBJECTIVE

Using integrated expression analyses of miRs, their mRNA and protein targets and stromal gene expression, we aimed to identify differentially expressed profiles between tumors from YA-BC and MA-BC.

METHODOLOGY AND RESULTS

Samples of ER+ invasive ductal breast carcinomas, divided into two groups: YA-BC (35 years or less) or MA-BC (50-65 years) were evaluated. Screening for BRCA1/2 status according to the BOADICEA program indicated low risk of patients being carriers of these mutations. Aggressive characteristics were more evident in YA-BC versus MA-BC. Performing qPCR, we identified eight miRs differentially expressed (miR-9, 18b, 33b, 106a, 106b, 210, 518a-3p and miR-372) between YA-BC and MA-BC tumors with high confidence statement, which were associated with aggressive clinicopathological characteristics. The expression profiles by microarray identified 602 predicted target genes associated to proliferation, cell cycle and development biological functions. Performing RPPA, 24 target proteins differed between both groups and 21 were interconnected within a network protein-protein interactions associated with proliferation, development and metabolism pathways over represented in YA-BC. Combination of eight mRNA targets or the combination of eight target proteins defined indicators able to classify individual samples into YA-BC or MA-BC groups. Fibroblast-enriched stroma expression profile analysis resulted in 308 stromal genes differentially expressed between YA-BC and MA-BC.

CONCLUSION

We defined a set of differentially expressed miRNAs, their mRNAs and protein targets and stromal genes that distinguish early onset from late onset ER positive breast cancers which may be involved with tumor aggressiveness of YA-BC.

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.

MicroRNA-148b targets Rho-associated protein kinase 1 to inhibit cell proliferation, migration and invasion in hepatocellular carcinoma

microRNA(miR)-148b has been found to be downregulated in various human malignancies, including hepatocellular carcinoma (HCC) as well as gastric, pancreatic, colon and oral cancer. However, the function of miR‑148b in HCC has remained elusive. The present study examined the effects of miR‑148b on the proliferation, migration and invasion of HCC cells in vitro. After transfection of the HepG2 and SMMC‑7721 HCC cell lines with miR‑148b, an MTT assay, a Transwell migration and invasion assay as well as western blot analysis were performed. miR-148b was shown to inhibit cell proliferation, migration and invasion in the two cell lines. Using a luciferase reporter assay, the present study also provided the first evidence that miR‑148b directly targets Rho‑associated protein kinase 1 in HCC. These results suggested that miR-148 may represent a novel molecular marker and a potential molecular therapeutic for inhibiting metastasis of HCC.

miR-451a Inhibited Cell Proliferation and Enhanced Tamoxifen Sensitive in Breast Cancer via Macrophage Migration Inhibitory Factor

This study aims to investigate the regulative effects of microRNA-451a (miR-451a) on cell proliferation and sensitivity to tamoxifen in breast cancer cells. In cell culture experiments, the lentiviral vectors of pHBLV-miR-451a and pHBLV-miR-451a sponge were constructed and used to transfect MCF-7 and LCC2 cells. The transfection efficiency was tested by fluorescent observation, and cell lines with stable over- or downregulated expression of miR-451a were established. The expression of miR-451a and the target gene macrophage migration inhibitory factor (MIF) were detected by real-time reverse transcriptase polymerase chain reaction and/or western blot. Moreover, MTT assay, colony formation, and Transwell invasion assays were also performed. Data showed that the recombinant lentiviral vectors were constructed correctly, and the virus titer was 1 × 10(8) CFU/mL. The stable transfected cells were obtained. Overexpression of miR-451a downregulated MIF expression in mRNA and protein levels and inhibited cell proliferation, colony formation, and invasion of breast cancer cells. Downregulation of miR-451a upregulated MIF expression and increased breast cancer cell growth, invasion, and tamoxifen sensitivity. In summary, the miR-451a/MIF pathway may play important roles in the biological properties of breast cancer cells and may be a potential therapeutic target for breast cancer.