miR-21: A gene of dual regulation in breast cancer

An update on the molecular mechanisms underlying the progression of miR-21 in oral cancer

Globally, oral cancer ranks among the top ten cancers, with a higher prevalence in lower-income countries, where risk factors such as tobacco use, excessive alcohol consumption, and poor oral hygiene are widespread. Metastasis plays a critical role in cancer progression. miR-21 is a crucial regulator of cancer metastasis, profoundly influencing cellular and molecular pathways that contribute to tumour aggressiveness. As a microRNA, miR-21 downregulates tumour suppressor genes, promoting cell proliferation, survival, invasion, and migration. Its role in epithelial-mesenchymal transition (EMT) further facilitates metastatic behaviour. miR-21 also modulates the tumour microenvironment by promoting angiogenesis and altering immune responses, thus enhancing cancer progression.Moreover, miRNA - 21 influences the various signalling pathways like PI3K/ AKT, TGF-β, NF-κB, and STAT3, as well as involved in the cell fate mechanisms known as Autophagy and apoptosis. Clinically, elevated miR-21 levels are associated with poor prognosis, advanced tumour stages, and decreased survival rates, making it a valuable prognostic marker. Additionally, miR-21 expression levels can predict resistance to chemotherapy and targeted therapies, aiding in personalized treatment planning. Therapeutically, targeting miR-21 through anti-miR-21 oligonucleotides, small molecule inhibitors, and miRNA sponges shows promise in pre-clinical studies, potentially inhibiting tumour growth and improving sensitivity to existing treatments. Overall, miR-21's multifaceted role in cancer biology, its prognostic and predictive value, and its potential as a therapeutic target highlight its significance in advancing cancer diagnosis, treatment, and patient outcomes. Further research and clinical trials are essential to exploit miR-21's capabilities in oncology fully.

Liquid biopsy technologies: innovations and future directions in breast cancer biomarker detection

Globally, breast cancer is the most frequent type of cancer, and its early diagnosis and screening can significantly improve the probability of survival and quality of life of those affected. Liquid biopsy-based targets such as circulating tumor cells, circulating tumor DNA, and exosomes have been instrumental in the early discovery of cancer, and have been found to be effective in stage therapy, recurrence monitoring, and drug selection. Biosensors based on these target related biomarkers convert the tested substances into quantifiable signals such as electrical and optical signals through signal transduction, which has the advantages of high sensitivity, simple operation, and low invasiveness. This review provides an overview of the latest progress of liquid biopsy biomarkers in the diagnosis, prognosis and treatment of breast cancer, compares the application and advantages of different biosensors based on these biomarkers in the diagnosis of breast cancer, and analyzes the limitations and solutions of biosensor based methods.

Impacts and potential mechanisms of fine particulate matter (PM2.5) on male testosterone biosynthesis disruption

Exposure to PM2.5 is the most significant air pollutant for health risk. The testosterone level in male is vulnerable to environmental toxicants. In the past, researchers focused more attention on the impacts of PM2.5 on respiratory system, cardiovascular system, and nervous system, and few researchers focused attention on the reproductive system. Recent studies have reported that PM2.5 involved in male testosterone biosynthesis disruption, which is closely associated with male reproductive health. However, the underlying mechanisms by which PM2.5 causes testosterone biosynthesis disruption are still not clear. To better understand its potential mechanisms, we based on the existing scientific publications to critically and comprehensively reviewed the role and potential mechanisms of PM2.5 that are participated in testosterone biosynthesis in male. In this review, we summarized the potential mechanisms of PM2.5 triggering the change of testosterone level in male, which involve in oxidative stress, inflammatory response, ferroptosis, pyroptosis, autophagy and mitophagy, microRNAs (miRNAs), endoplasmic reticulum (ER) stress, and N6-methyladenosine (m6A) modification. It will provide new suggestions and ideas for prevention and treatment of testosterone biosynthesis disruption caused by PM2.5 for future research.

The diagnostic significance of circulating miRNAs and metabolite profiling in early prediction of breast cancer in Egyptian women

OBJECTIVE

Breast cancer (BC) is one of the most commonly diagnosed solid malignancies in women worldwide.

PURPOSE

Finding new non-invasive circulating diagnostic biomarkers will facilitate the early prediction of BC and provide valuable insight into disease progression and response to therapy using a safe and more accessible approach available every inspection time. Therefore, our present study aimed to investigate expression patterns of potentially circulating biomarkers that can differentiate well between benign, malignant, and healthy subjects.

METHODS

To achieve our target, quantitative analyses were performed for some circulating biomarkers which have a role in the proliferation and tumor growth, as well as, glutamic acid, and human epidermal growth receptor 2 (HER2) in blood samples of BC patients in comparison to healthy controls using qRT-PCR, liquid chromatography/mass spectrometry (LC/MS/MS), and ELISA.

RESULTS

Our findings showed that the two miRNAs (miRNA-145, miRNA-382) were expressed at lower levels in BC sera than healthy control group, while miRNA-21 was expressed at higher levels in BC patients than control subjects. Area under ROC curves of BC samples revealed that AUC of miRNA-145, miRNA-382, miRNA-21, and glutamic acid was evaluated to equal 0.99, 1.00, 1.00 and 1.00, respectively. Besides, there was a significantly positive correlation between miRNA-145 and miRNA-382 (r = 0.737), and a highly significant positive correlation between miRNA-21 and glutamic acid (r = 0.385).

CONCLUSION

Based on our results, we conclude that the detection of serum miRNA-145, -382 and -21 as a panel along with glutamic acid, and circulating HER2 concentrations could be useful as a non-invasive diagnostic profiling for early prediction of breast cancer in Egyptian patients. It can provide an insight into disease progression, discriminate between malignancy and healthy control, and overcome the use limitations (low sensitivity and specificity, repeated risky exposure, and high cost) of other detecting tools, including mammography, magnetic resonance imaging, and ultrasound.

Prognostic and diagnostic values of non-coding RNAs as biomarkers for breast cancer: An umbrella review and pan-cancer analysis

Background: Breast cancer (BC) is the most common cancer in women. The incidence and morbidity of BC are expected to rise rapidly. The stage at which BC is diagnosed has a significant impact on clinical outcomes. When detected early, an overall 5-year survival rate of up to 90% is possible. Although numerous studies have been conducted to assess the prognostic and diagnostic values of non-coding RNAs (ncRNAs) in breast cancer, their overall potential remains unclear. In this field of study, there are various systematic reviews and meta-analysis studies that report volumes of data. In this study, we tried to collect all these systematic reviews and meta-analysis studies in order to re-analyze their data without any restriction to breast cancer or non-coding RNA type, to make it as comprehensive as possible. Methods: Three databases, namely, PubMed, Scopus, and Web of Science (WoS), were searched to find any relevant meta-analysis studies. After thoroughly searching, the screening of titles, abstracts, and full-text and the quality of all included studies were assessed using the AMSTAR tool. All the required data including hazard ratios (HRs), sensitivity (SENS), and specificity (SPEC) were extracted for further analysis, and all analyses were carried out using Stata. Results: In the prognostic part, our initial search of three databases produced 10,548 articles, of which 58 studies were included in the current study. We assessed the correlation of non-coding RNA (ncRNA) expression with different survival outcomes in breast cancer patients: overall survival (OS) (HR = 1.521), disease-free survival (DFS) (HR = 1.33), recurrence-free survival (RFS) (HR = 1.66), progression-free survival (PFS) (HR = 1.71), metastasis-free survival (MFS) (HR = 0.90), and disease-specific survival (DSS) (HR = 0.37). After eliminating low-quality studies, the results did not change significantly. In the diagnostic part, 22 articles and 30 datasets were retrieved from 8,453 articles. The quality of all studies was determined. The bivariate and random-effects models were used to assess the diagnostic value of ncRNAs. The overall area under the curve (AUC) of ncRNAs in differentiated patients is 0.88 (SENS: 80% and SPEC: 82%). There was no difference in the potential of single and combined ncRNAs in differentiated BC patients. However, the overall potential of microRNAs (miRNAs) is higher than that of long non-coding RNAs (lncRNAs). No evidence of publication bias was found in the current study. Nine miRNAs, four lncRNAs, and five gene targets showed significant OS and RFS between normal and cancer patients based on pan-cancer data analysis, demonstrating their potential prognostic value. Conclusion: The present umbrella review showed that ncRNAs, including lncRNAs and miRNAs, can be used as prognostic and diagnostic biomarkers for breast cancer patients, regardless of the sample sources, ethnicity of patients, and subtype of breast cancer.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

Potential role of circulating miR-21 in the diagnosis of hepatocellular carcinoma: a systematic review and meta-analysis

OBJECTIVE

Identify original articles that analyzed the diagnostic value of miR-21 in hepatocellular carcinoma without language restriction or publication date.

METHODOLOGY

We performed structured searches on PubMed, Web of Science, VHL, and EMBASE. The Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields was used to assess the quality of each study. Random effect models were used to study heterogeneity, evaluated based on the Higgins I2 statistic.

RESULTS

12 articles were evaluated and contained raw data from 1,329 individuals, of which 617 had HCC, 473 were healthy, and 239 had Chronic liver disease. The combined sensitivity and combined specificity of miR-21 for diagnosing HCC were, respectively, 0.83(95% CI:0.78-0.89) and 0.85(95% CI:0.80-0.90). The sensitivity and specificity, in that order, by type of control were 0.81 (95% CI: 0.71-0.91) and 0.88 (95% CI: 0.82-0.93) for CLDs and 0.86(95% CI: 0.81-0.91) and 0.83(95% CI:0.74-0.91) for Healthy controls.

CONCLUSION

miR-21 has a moderate overall performance in diagnosing HCC and may serve as a potential non-invasive marker for this early-stage disease. Thus, it may contribute to complementing the results of alpha-fetoprotein in the diagnosis and help to detect HCC at an earlier stage, increasing the survival chances of these patients.

Downregulation of miR-21 as a promising strategy to overcome drug resistance in cancer

Despite tremendous achievements in the field of targeted cancer therapy, chemotherapy is still the main treatment option, which is challenged by acquired drug resistance. Various microRNAs are involved in developing drug-resistant cells. miR-21 is one of the first identified miRNAs involved in this process. Here, we conducted a literature review to categorize different mechanisms employed by miR-21 to drive drug resistance. miR-21 targets various genes involved in many pathways that can justify chemoresistance. It alters cancer cell metabolism and facilitates adaptation to the new environment. It also enhances drug detoxification in cancerous cells and increases genomic instability. We also summarized various strategies applied for the inhibition of miR-21 in order to reverse cancer drug resistance. These strategies include the delivery of antagomiRs, miRZip knockdown vectors, inhibitory small molecules, CRISPR-Cas9 technology, catalytic nucleic acids, artificial DNA and RNA sponges, and nanostructures like mesoporous silica nanoparticles, dendrimers, and exosomes. Furthermore, current challenges and limitations in targeting miR-21 are discussed in this article. Although huge progress has been made in the downregulation of miR-21 in drug-resistant cancer cells, there are still many challenges to be resolved. More research is still required to find the best strategy and timeline for the downregulation of miR-21 and also the most feasible approach for the delivery of this system into the tumor cells. In conclusion, downregulation of miR-21 would be a promising strategy to reverse chemoresistance, but still, more studies are required to clarify the aforementioned issues.

Andrographolide Exhibits Anticancer Activity against Breast Cancer Cells (MCF-7 and MDA-MB-231 Cells) through Suppressing Cell Proliferation and Inducing Cell Apoptosis via Inactivation of ER-α Receptor and PI3K/AKT/mTOR Signaling

Breast cancer is the most common cancer among women worldwide. Chemotherapy followed by endocrine therapy is the standard treatment strategy after surgery or radiotherapy. However, breast cancer is highly resistant to the treatments leading to the recurrence of breast cancer. As a result, the development of alternative medicines derived from natural plants with fewer side effects is being emphasized. Andrographolide isolated from Andrographis paniculata is one of the potential substances with anti-cancer properties in a variety of cell types, including breast cancer cells. This study aims to investigate the anti-cancer effects of andrographolide in breast cancer cells by evaluating cell viability and apoptosis as well as its underlying mechanisms through estrogen receptor (ER)-dependent and PI3K/AKT/mTOR signaling pathways. Cell viability, cell apoptosis, mRNA or miRNA, and protein expression were examined by MTT assay, Annexin V-FITC, qRT-PCR, and Western blot analysis, respectively. MCF-7 and MDA-MB-231 cell viability was reduced in a concentration- and time-dependent manner after andrographolide treatment. Moreover, andrographolide induced cell apoptosis in both MCF-7 and MDA-MB-231 cells by inhibiting Bcl-2 and enhancing Bax expression at both mRNA and protein levels. In MCF-7 cells, the ER-positive breast cancer, andrographolide showed an inhibitory effect on cell proliferation through downregulation of ERα, PI3K, and mTOR expression levels. Andrographolide also inhibited MDA-MB-231 breast cancer cell proliferation via induction of cell apoptosis. However, the inhibition of MCF-7 and MDA-MB-231 cell proliferation of andrographolide treatment did not disrupt miR-21. Our findings showed that andrographolide possesses an anti-estrogenic effect by suppressing cell proliferation in MCF-7 cells. The effects were comparable to those of the anticancer drug fulvestrant in MCF-7 cells. This study provides new insights into the anti-cancer effect of andrographolide on breast cancer and suggests andrographolide as a potential alternative from the natural plant for treating breast cancer types that are resistant to tamoxifen and fulvestrant.

Non-Exosomal and Exosome-Derived miRNAs as Promising Biomarkers in Canine Mammary Cancer

Canine mammary cancer (CMC), similar to human breast cancer (HBC) in many aspects, is the most common neoplasm associated with significant mortality in female dogs. Due to the limited therapy options, biomarkers are highly desirable for early clinical diagnosis or cancer progression monitoring. Since the discovery of microRNAs (miRNAs or miRs) as post-transcriptional gene regulators, they have become attractive biomarkers in oncological research. Except for intracellular miRNAs and cell-free miRNAs, exosome-derived miRNAs (exomiRs) have drawn much attention in recent years as biomarkers for cancer detection. Analysis of exosomes represents a non-invasive, pain-free, time- and money-saving alternative to conventional tissue biopsy. The purpose of this review is to provide a summary of miRNAs that come from non-exosomal sources (canine mammary tumor, mammary tumor cell lines or canine blood serum) and from exosomes as promising biomarkers of CMC based on the current literature. As is discussed, some of the miRNAs postulated as diagnostic or prognostic biomarkers in CMC were also altered in HBC (such as miR-21, miR-29b, miR-141, miR-429, miR-200c, miR-497, miR-210, miR-96, miR-18a, miR19b, miR-20b, miR-93, miR-101, miR-105a, miR-130a, miR-200c, miR-340, miR-486), which may be considered as potential disease-specific biomarkers in both CMC and HBC.

Fine-tuning miR-21 expression and inhibition of EMT in breast cancer cells using aromatic-neomycin derivatives

MicroRNAs (miRs) are a class of endogenously expressed non-coding RNAs that negatively regulate gene expression within cells and participate in maintaining cellular homeostasis. By targeting 3' UTRs of target genes, individual miRs can control a wide array of gene expressions. Previous research has shed light upon the fact that aberrantly expressed miRs within cells can pertain to diseased conditions, such as cancer. Malignancies caused due to miRs are because of the high expression of onco-miRs or feeble expression of tumor-suppressing miRs. Studies have also shown miRs to engage in epithelial to mesenchymal transition (EMT), which allows cancer cells to become more invasive and metastasize. miR-21 is an onco-miR highly expressed in breast cancer cells and targets protein PTEN, which abrogates EMT. Therefore, we discuss an approach where in-house-developed peptidic amino sugar molecules have been used to target pre-miR-21 to inhibit miR-21 biogenesis, and hence antagonize its tumor-causing effect and inhibit EMT. Our study shows that small-molecule-based fine-tuning of miR expression can cause genotypic as well as phenotypic changes and also reinstates the potential and importance of nucleic acid therapeutics.

MicroRNAs Role in Breast Cancer: Theranostic Application in Saudi Arabia

Breast cancer is an aggressive silent disease, representing 11.7% of the diagnosed cancer worldwide, and it is also a leading cause of death in Saudi Arabia. Consequently, microRNAs have emerged recently as potential biomarkers to diagnose and monitor such cases at the molecular level, which tends to be problematic during diagnosis. MicroRNAs are highly conserved non- coding oligonucleotide RNA. Over the last two decades, studies have determined the functional significance of these small RNAs and their impact on cellular development and the interaction between microRNAs and messenger RNAs, which affect numerous molecular pathways and physiological functions. Moreover, many disorders, including breast cancer, are associated with the dysregulation of microRNA. Sparingly, many microRNAs can suppress cancer cell proliferation, apoptosis, angiogenesis, invasion, metastasis, and vice versa. Remarkably, microRNAs can be harvested from patients’ biofluids to predict disease progression that considered a non-invasive method. Nevertheless, MicroRNAs are currently utilized as anti- cancer therapies combined with other drug therapies or even as a single agents’ treatment. Therefore, this review will focus on microRNAs’ role in breast cancer as an indicator of disease progression. In addition, this review summarizes the current knowledge of drug sensitivity and methods in detecting microRNA and their application to improve patient care and identifies the current gaps in this field.

Novel miR-5088-5p promotes malignancy of breast cancer by inhibiting DBC2

Breast cancer is the most common female cancer in the world. Despite the active research on metastatic breast cancer, the treatment of breast cancer patients is still difficult because the mechanism is not well known. Therefore, research on new targets and mechanisms for diagnosis and treatment of breast cancer patients is required. On the other hand, microRNA (miRNA) has the advantage of simultaneously regulating the expression of many target genes, so it has been proposed as an effective biomarker for the treatment of various diseases including cancer. This study analyzed the role and mechanism of DBC2 (deleted in breast cancer 2), which is known to inhibit its expression in breast cancer, and proposed microRNA (miR)-5088-5p, which regulates its expression. It was revealed that the biogenesis of miR-5088-5p was upregulated by hypomethylation of its promoter, promoted by Fyn, and was involved in malignancy in breast cancer. With the use of the cellular level, clinical samples, and published data, we verified that the expression patterns of DBC2 and miR-5088-5p were negatively related, suggesting the potential as novel biomarkers for the diagnosis of breast cancer patients.

MicroRNAs: The Link between the Metabolic Syndrome and Oncogenesis

Metabolic syndrome (MetS) represents a cluster of disorders that increase the risk of a plethora of conditions, in particular type two diabetes, cardiovascular diseases, and certain types of cancers. MetS is a complex entity characterized by a chronic inflammatory state that implies dysregulations of adipokins and proinflammatory cytokins together with hormonal and growth factors imbalances. Of great interest is the implication of microRNA (miRNA, miR), non-coding RNA, in cancer genesis, progression, and metastasis. The adipose tissue serves as an important source of miRs, which represent a novel class of adipokines, that play a crucial role in carcinogenesis. Altered miRs secretion in the adipose tissue, in the context of MetS, might explain their implication in the oncogenesis. The interplay between miRs expressed in adipose tissue, their dysregulation and cancer pathogenesis are still intriguing, taking into consideration the fact that miRNAs show both carcinogenic and tumor suppressor effects. The aim of our review was to discuss the latest publications concerning the implication of miRs dysregulation in MetS and their significance in tumoral signaling pathways. Furthermore, we emphasized the role of miRNAs as potential target therapies and their implication in cancer progression and metastasis.

Screening of miRNAs associated with lymph node metastasis in Her-2-positive breast cancer and their relationship with prognosis

The aim of this study was to identify some biomarkers for predicting lymph node metastasis and prognosis of human epidermal growth factor receptor 2 (Her-2)-positive breast cancer (BC). We analyzed correlations between microRNAs (miRNAs) and the prognosis of patients with BC based on data collected from The Cancer Genome Atlas (TCGA) database. The expression levels of miR-455, miR-143, and miR-99a were measured in clinical samples of Her-2-positive BC patients with different degrees of lymph node metastasis. We investigated the impacts of overexpressed miR-455 on the proliferation and invasiveness of MDA-MB-453 cells and measured its effects on the expression of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of miR-455 was significantly and positively correlated to the prognosis and overall survival (OS) of the BC (P=0.028), according to TCGA information. The expression level of miR-455 was positively correlated with OS and relapse-free survival (RFS) of patients with Her-2-positive BC, and was negatively correlated with the number of metastatic lymph nodes (P<0.05). Transwell assay suggested that MDA-MB-453 cells became much less invasive (P<0.01) after being transfected with miR-455 mimics. During the qRT-PCR, the expression level of MALAT1 declined significantly after transfection (P<0.01). Overexpressed miR-455 significantly inhibited the proliferation and migration of MDA-MB-453 cells and the expression of MALAT1. We conclude that miR-455 may be a useful potential biomarker for forecasting lymph node metastasis and the prognosis of Her-2-positive BC patients. miR-455 may play an important role in lymph node metastasis of BC by interacting with MALAT1.

miR-210 and miR-152 as Biomarkers by Liquid Biopsy in Invasive Ductal Carcinoma

Detecting circulating microRNAs (miRNAs; miRs) by means of liquid biopsy is an important tool for the early diagnosis and prognosis of breast cancer (BC). We aimed to identify and validate miR-210 and miR-152 as non-invasive circulating biomarkers, for the diagnosis and staging of BC patients, confirming their involvement in tumor angiogenesis. Methods: RT-qPCR was performed and MiRNA expression analysis was obtained from plasma and fragments of BC and benign breast condition (BBC) women patients, plus healthy subjects. Additionally, the immunohistochemistry technique was carried out to analyze the expression of target proteins. Results: Tumor fragments showed increased expression of oncomiR-210 and decreased expression of miR-152 tumoral suppressor. Both miRNAs were increased in plasma samples from BC patients. The receiver operating characteristic (ROC) curve analysis revealed that only the expression of oncomiR-210 in tissue samples and only the expression of the miR-152 suppressor in plasma have the appropriate sensitivity and specificity for use as differential biomarkers between early/intermediate and advanced stages of BC patients. In addition, there was an increase in the expression of hypoxia-inducible factor 1-alpha (HIF-1α), insulin-like growth factor 1 receptor (IGF-1R), and vascular endothelial growth factor (VEGF) in BC patients. On the contrary, a decrease in Von Hippel–Lindau (VHL) protein expression was observed. Conclusions: This study showed that increased levels of miR-210 and decreased levels of miR152, in addition to the expressions of their target proteins, could indicate, respectively, the oncogenic and tumor suppressive role of these miRNAs in fragments. Both miRNAs are potential diagnostic biomarkers for BC by liquid biopsy. In addition, miR-152 proved to be a promising biomarker for disease staging.

Associations Between miRNAs and Two Different Cancers: Breast and Colon

Objective

Screening approaches using microRNAs (miRNAs) have been gaining increased attention owing to their potential applications in the diagnosis, prognosis, and monitoring of cancer, because aberrant miRNA expression plays a role in the development and advancement of malignancies. The objectives of this study were to characterize mir21, miR31, mir143, mir145, and control RNU43, which are differentially expressed in peripheral blood mononuclear cells (PBMCs) of breast and colorectal cancer patients, compared to that in controls and to establish whether this is specific to breast and colon cancer for use as tumor markers.

Methods

Thirty newly diagnosed patients with breast cancer and 30 patients with colorectal cancer were enrolled together with 30 healthy controls. PBMCs were isolated from venous blood samples of individuals. Next, miRNA expression analysis was performed by a two-step method of reverse transcription and qPCR.

Results

The expression levels of miR-143 and miR-31 were significantly decreased, whereas the expression levels of miR-145 and miR-21 were significantly increased in breast cancer patients compared to those in healthy subjects. Moreover, the expression levels of miR-143, miR-145, and miR-21 were significantly increased and, in contrast, the changes in the expression levels of miR-31 were not statistically significant in colon cancer compared to those in healthy subjects. miR-21 exhibited the highest increase in both breast and colon cancers. There was a weak positive correlation between miR-145 and CA-15.3 in patients with breast cancer (r = 0.451; p = 0.012). miR-143 was positively correlated with the TNM stage in colon cancer patients (r = 0.568; p = 0.001).

Conclusion

A biomarker panel composed of miR-21, miR-31, miR-143, and miR-145 in PBMC may provide a new diagnostic approach for the early detection of breast and colon cancer. As miR-21 expression was found to be the highest among all the miRNAs evaluated, it may represent a new tumor biomarker and a candidate therapeutic drug or gene target in colon and breast cancer.

Simultaneous downregulation of miR-21 and upregulation of miR-7 has anti-tumor efficacy

Dysregulation of miRNA expression has been implicated in cancer. Numerous strategies have been explored to modulate miR but sub-optimal delivery and inability to concurrently target multiple pathways involved in tumor progression have limited their efficacy. In this study, we explored the potential co-modulation of upregulated miR-21 and downregulated miR-7 to enhance therapeutic outcomes in heterogenic tumor types. We first engineered lentiviral (LV) and adeno-associated viral (AAV) vectors that preferentially express anti-sense miR against miR-21(miRzip-21) and show that modulating miR-21 via miRzip extensively targets tumor cell proliferation, migration and invasion in vitro in a broad spectrum of cancer types and has therapeutic efficacy in vivo. Next, we show a significantly increased expression of caspase-mediated apoptosis by simultaneously downregulating miR-21 and upregulating miR-7 in different tumor cells. In vivo co-treatment with AAV-miRzip-21 and AAV-miR-7 in mice bearing malignant brain tumors resulted in significantly decreased tumor burden with a corresponding increase in survival. To our knowledge, this is the first study that demonstrates the therapeutic efficacy of simultaneously upregulating miR-7 and downregulating miR-21 and establishes a roadmap towards clinical translation of modulating miRs for various cancer types.

Overexpression of microRNA-21 in the Serum of Breast Cancer Patients

BACKGROUND

Breast cancer is the most common cancer diagnosed in women worldwide. So it seems that there's a good chance of recovery if it's detected in its early stages even before the appearances of symptoms. Recent studies have shown that miRNAs play an important role during cancer progression. These transcripts can be tracked in liquid samples to reveal if cancer exists, for earlier treatment. MicroRNA-21 (miR-21) has been shown to be a key regulator of carcinogenesis, and breast tumor is no exception.

OBJECTIVE

The present study was aimed to track the miR-21 expression level in serum of the breast cancer patients in comparison with that of normal counterparts.

METHODS

Comparative real-time polymerase chain reaction was applied to determine the levels of expression of miR-21 in the serum samples of 57 participants from which, 42 were the patients with breast cancer including pre-surgery patients (n = 30) and post-surgery patients (n = 12), and the others were the healthy controls (n = 15).

RESULTS

MiR-21 was significantly over expressed in the serum of breast cancer patients as compared with healthy controls (P = 0.002). A significant decrease was also observed following tumor resection (P < 0.0001). Moreover, it was found that miR-21 overexpression level was significantly associated with tumor grade (P = 0.004).

CONCLUSION

These findings suggest that miR-21 has the potential to be used as a novel breast cancer biomarker for early detection and prognosis, although further experiments are needed.

Inhibition of breast cancer cell proliferation with anti-microRNA oligonucleotides flanked by interstrand cross-linked duplexes

Breast cancer is the most frequent cancer affecting women worldwide. Traditional chemotherapy, hormone therapy, and targeted therapy are used for breast cancer treatment. However, breast cancer is a heterogeneous disease, and patients often develop drug resistance. Therefore, various new therapeutic strategies have been investigated, including microRNA regulation. Anti-microRNA oligonucleotides (AMOs) are one of the most potent agents in oligonucleotide therapy. The inhibition activity of an AMO can be increased by flanking its single-stranded antisense sequence (the widely used structure for AMOs) with interstrand cross-linked duplexes (CLDs). An extrastable CLD improves nuclease resistance and stabilizes hybridization with a target. This study investigated the effects of anti-microRNA-21 (miR-21) AMO modified with CLDs on breast cancer cells without using reporter assay. The CLD-modified AMO suppressed breast cancer cell proliferation for a long duration compared to other types of AMOs. In addition, it expectedly up-regulated the miR-21-controlled expression of tumor suppressor genes. Therefore, an AMO flanked by CLDs can be a promising strategy for breast cancer treatment.

Development of Novel antimiRzymes for Targeted Inhibition of miR-21 Expression in Solid Cancer Cells

MicroRNAs (miRNAs) are short non-coding RNAs that are involved in the regulation of gene expression. Previous reports showed an over-expression of miRNA-21 (miR-21) in various cancer cells, and its up-regulation is closely related to cancer initiation, proliferation and metastasis. In this work, we envisioned the development of novel antimiRzymes (anti-miRNA-DNAzyme) that are capable of selectively targeting and cleaving miR-21 and inhibit its expression in cancer cells using the DNAzyme technique. For this purpose, we have designed different antimiRzyme candidates by systematically targeting different regions of miR-21. Our results demonstrated that RNV541, a potential arm-loop-arm type antimiRzyme, was very efficient (90%) to suppress miR-21 expression in U87MG malignant glioblastoma cell line at 200 nM concentration. In addition, RNV541 also inhibited miR-21 expression (50%) in MDA-MB-231 breast cancer cell line. For targeted delivery, we conjugated RNV541 with a transferrin receptor (TfR) targeting aptamer for TfR-mediated cancer cell delivery. As expected, the developed chimeric structure efficiently delivered the antimiRzyme RNV541 into TfR positive glioblastoma cells. TfR aptamer-RNV541 chimeric construct showed 52% inhibition of miR-21 expression in U87MG glioblastoma cells at 2000 nM concentration, without using any transfection reagents, making it a highly desirable strategy to tackle miR-21 over-expressed malignant cancers. Although these are in vitro based observations, based on our results, we firmly believe that our findings could be beneficial towards the development of targeted cancer therapeutics where conventional therapies face several challenges.

Therapeutic microRNAs in human cancer

MicroRNAs (miRNAs) are RNA molecules at about 22 nucleotide in length that are non-coding, which regulate gene expression in the post-transcriptional level by performing degradation or blocks translation of the target mRNA. It is known that they play roles in mechanisms such as metabolic regulation, embryogenesis, organogenesis, differentiation and growth control by providing post-transcriptional regulation of gene expression. With these properties, miRNAs play important roles in the regulation of biological processes such as proliferation, differentiation, apoptosis, drug resistance mechanisms in eukaryotic cells. In addition, there are miRNAs that can be used for cancer therapy. Tumor cells and tumor microenvironment have different miRNA expression profiles. Some miRNAs are known to play a role in the onset and progression of the tumor. miRNAs with oncogenic or tumor suppressive activity specific to different cancer types are still being investigated. This review summarizes the role of miRNAs in tumorigenesis, therapeutic strategies in human cancer and current studies.

Advanced microRNA-based cancer diagnostics using amplified time-gated FRET

MicroRNAs (miRNAs) play an important role in cellular functions and in the development and progression of cancer. Precise quantification of endogenous miRNAs from different clinical patient and control samples combined with a one-to-one comparison to standard technologies is a challenging but necessary endeavor that is largely neglected by many emerging fluorescence technologies. Here, we present a simple, precise, sensitive, and specific ratiometric assay for absolute quantification of miRNAs. Isothermally amplified time-gated Förster resonance energy transfer (TG-FRET) between Tb donors and dye acceptors resulted in miRNA assays with single-nucleotide variant specificity and detection limits down to 4.2 ± 0.5 attomoles. Quantification of miR-21 from human tissues and plasma samples revealed the relevance for breast and ovarian cancer diagnostics. Analysis of miR-132 and miR-146a from acute monocytic leukemia cells (THP-1) demonstrated the broad applicability to different miRNAs and other types of clinical samples. Direct comparison to the gold standard RT-qPCR showed advantages of amplified TG-FRET concerning precision and specificity when quantifying low concentrations of miRNAs as required for diagnostic applications. Our results demonstrate that a careful implementation of rolling circle amplification and TG-FRET into one straightforward nucleic acid detection method can significantly advance the possibilities of miRNA-based cancer diagnostics and research.

Exosomes Released from Tumor-Associated Macrophages Transfer miRNAs That Induce a Treg/Th17 Cell Imbalance in Epithelial Ovarian Cancer

The immune microenvironment is crucial for epithelial ovarian cancer (EOC) progression and consists of tumor-associated macrophages (TAM) and T lymphocytes, such as regulatory T cells (Treg) and T helper 17 (Th17) cells. In this study, the Treg/Th17 ratio was significantly higher in EOC in situ and in metastatic peritoneal tissues than in benign ovarian tumors and benign peritoneum. The Treg/Th17 ratio was associated with histologic grade and was an independent prognostic factor for overall survival of EOC patients. On the basis of microarray analysis of exosomes derived from TAMs, we identified miRNAs enriched in the exosomes, including miR-29a-3p and miR-21-5p. When the two miRNA mimics were transfected into CD4⁺ T cells, they directly suppressed STAT3 and regulated Treg/Th17 cells, inducing an imbalance, and they had a synergistic effect on STAT3 inhibition. Taken together, these results indicate that exosomes mediate the interaction between TAMs and T cells, generating an immune-suppressive microenvironment that facilitates EOC progression and metastasis. These findings suggest that targeting these exosomes or their associated miRNAs might pave the way for the development of novel treatments for EOC.

Serum microRNA as potential biomarker to detect breast atypical hyperplasia and early-stage breast cancer

AIM

The present study aimed to identify microRNA (miRNA) that can be used for not only detecting early-stage breast cancer (BC) but also diagnosing atypical hyperplasia (AH).

MATERIALS & METHODS

RT-qPCR detected the expression levels of miRNAs and receiver operating characteristic curves were constructed to evaluate sensitivity and specificity of the assay.

RESULTS

miR-24 and miR-103a were expressed in an upward trend in serum of benign proliferative tumor subjects, while they were downregulated significantly in serum of AH (p < 0.005) and early-stage BC subjects (p < 0.005) with high sensitivity and specificity as compared with controls. Bioinformatics analysis also revealed the potential molecular mechanism through which miR-24 and miR-103a regulate tumorigenesis in BC.

CONCLUSION

miR-24 and miR-103a were valuable biomarkers for distinguishing AH and early-stage BC from healthy individuals/benign proliferative tumor patients.

microRNA-761 regulates glycogen synthase kinase 3β expression and promotes the proliferation and cell cycle of human gastric cancer cells

It has been well documented that aberrant expression of microRNAs (miRs) serves important roles in cancer progression. The present study investigated the roles of miR-761 on gastric cancer (GC) cell proliferation. Reverse transcription polymerase chain reaction indicated that miR-761 was frequently upregulated in GC tissues and cells. Overexpression of miR-761 promoted the cell proliferation, cell colony formation and cell cycle of GC cells. Bioinformatics analysis revealed that miR-761 might target the 3′-untranslated region of glycogen synthase kinase 3β, and was confirmed by luciferase reporter assay and western blot analysis. Taken together, the results of the present study revealed miR-761 as a tumor promoter in GC, and that it could be considered as a novel therapeutic target for patients with GC.

Elevated miR-301a expression indicates a poor prognosis for breast cancer patients

Although microRNA-301a (miR-301a) has been reported to function as an oncogene in many human cancers, there are limited data regarding miR-301a and breast tumours. In this study, we first detected the expression of miR-301a using an in situ hybridization (ISH) -based classification system in 380 samples of BC tissue, including both non-TNBC (triple-negative breast cancer) and TNBC specimens. Our results suggest that analysing miR-301a expression in breast tissue biopsy specimens at the time of diagnosis could have the potential to identify patients who might be candidates for active surveillance. We validated our results that higher expression of miR-301a is associated with a decreased OS in independent public breast cancer databases, such as TCGA and METABRIC, using the online webtool Kaplan-Meier Plotter, which provided additional powerful evidence to confirm the prognostic value of miR-301a. MiR-301a may serve as a potential therapeutic target for patients with breast cancer. According to our results, miR-301a should be considered, and novel therapeutic options are needed to target this aggressive miR-301a-positive type of breast cancer to reduce recurrence and the mortality rate.

Proliferation-associated miRNAs-494, -205, -21 and -126 detected by in situ hybridization: expression and prognostic potential in breast carcinoma patients

PURPOSE

To visualize by in situ hybridization (ISH) the levels of a set of proliferation-associated miRNAs and to evaluate their impact and clinical applicability in prognostication of invasive breast carcinoma.

METHODS

Tissue specimen from breast carcinoma patients were investigated for miRNAs-494, -205, -21 and -126. Prognostic associations for levels of miRNAs were analyzed based on complete clinical data and up to 22.5-year follow-up of the patient material (n = 285). For detection of the miRNAs, an automated sensitive protocol applying in situ hybridization was developed.

RESULTS

MiRNA-494 indicated prognostic value for patients with invasive breast carcinoma. Among node-negative disease reduced level of miRNA-494 predicted 8.5-fold risk of breast cancer death (p = 0.04). Altered levels and expression patterns of the studied miRNAs were observed in breast carcinomas as compared to benign breast tissue.

CONCLUSIONS

The present paper reports for the first time on the prognostic value of miRNA-494 in invasive breast cancer. Particularly, detection of miRNA-494 could benefit patients with node-negative breast cancer in identifying subgroups with aggressive disease. Based on our experience, the developed automatic ISH method to visualize altered levels of miRNAs-494, -205, -21 and -126 could be applied to routine pathology diagnostics providing that conditions of tissue treatment, especially fixation delays, are managed.

Increased expression of miR-155 and miR-222 is associated with lymph node positive status

Identification of prognostic molecular markers of breast cancer is extremely important. The spreading out of the primary breast tumour cells to the lymphatic system is at the forefront of symbolising the first signs of distant organ metastasis. Deregulated genes in breast cancer tissues that spread to lymph nodes may show early predictive molecular markers. In the present study, we selected five microRNAs, which play a key function in the invasion-metastasis cascade. We investigated the levels of microRNAs in 80 paired samples of BC and matched adjoining tissues, and we examined the potential relationships between microRNA levels and positive lymph node status. Our results attest that three microRNAs (miR-21, miR-155, miR-222) were significantly up-regulated, whilst miR-205 was substantially down-regulated in BC tissues in relation to normal adjoining tissues in a heterogeneous patient cohort. The high levels of two microRNAs, miR-155 and miR-222, showed a statistical relation with the positive lymph node status, especially in patients that had triple negative BC. Conversely, miR-155 was substantially down-regulated in tumour tissues of patients who received preoperative neoadjuvant chemotherapy (NAC) compared with tumour tissues of patients without NAC in cohorts sub-classified to lymph node positive status. Our findings show evidence that the miR-155 and the miR-222 can be defined as molecular markers in regards to cancer patients to prognosticate spread to the lymph node. They also showed that the miR-155 could have crucial significances in BC treatment.

Expression of miR-195 is associated with chemotherapy sensitivity of cisplatin and clinical prognosis in gastric cancer

Gastric cancer has higher morbidity and mortality than other cancers for the low diagnosis rate and few therapies. MiR-195 has been reported to be involved in the occurrence, development and prognosis of various cancers. However, the function of miR-195 in gastric cancer remains largely unknown. Herein, the aims of this study were to probe the functional mechanism of miR-195 and its chemotherapy sensitivity as well as clinical prognosis in gastric cancer. We screened out low-expressed miR-195 through microarray analysis and further confirmed miR-195 was widely down-regulated in gastric cancer cells. Subsequently, AKT3 was identified as the direct target gene of miR-195 by target gene prediction software, dual luciferase reporter assay and western blot. Functional assays indicated that miR-195 acted as a tumor suppressor through regulating the proliferative, migrated and invasive properties of gastric cancer cells in vitro, and intratumoral delivery of miR-195 significantly suppressed tumor growth in vivo. Additionally, we also found miR-195 overexpression could enhance the chemotherapy sensitivity of cisplatin in gastric cancer cells and prolong the overall survival and progression free survival of gastric cancer patients. Collectively, our findings demonstrate miR-195 may be of great significance on early diagnosis of gastric cancer, providing the theoretical basis for prognosis and recurrence risk.

MicroRNA profiling and bioinformatics analyses reveal the potential roles of microRNAs in chordoma

Chordoma is a rare aggressive bone tumor arising from remnants of the notochord, and patients with chordoma have a poor prognosis. However, the unique expression profiles of microRNAs (miRNAs/miRs) and their downstream signaling pathways in chordoma remain incompletely characterized. The aim of the present study was to delineate the global miRNA expression profile and associated signaling networks in chordoma. miRNA profiling was performed on chordoma and fetal notochord tissues. Differentially expressed miRNAs in chordoma were analyzed using microarrays with hierarchical clustering analysis. The target genes of the differentially expressed miRNAs were predicted, and Gene Ontology (GO) and pathway analyses were performed for the intersecting genes. A total of 42 miRNAs were significantly dysregulated in chordoma compared with that in fetal nucleus pulposus tissues. The expression of hsa-miR-21-3p, hsa-miR-150-5p, hsa-miR-1290 and hsa-miR-623 were validated using the reverse transcription-quantitative polymerase chain reaction. On the basis of the intersection predicted by three databases (Targetscan, microRNA.org and PITA), 10,292 potential miRNA targets were identified. Bioinformatic analyses suggested that these dysregulated miRNAs and their predicted targets were functions of signaling pathways in cancer, the mitogen-activated protein kinase signaling pathway, regulation of actin cytoskeleton, focal adhesion and endocytosis. In particular, human (hsa-)miR-185-5p was identified as a crucial miRNA in chordoma development via the Wnt signaling pathway. The results of the present study provide a comprehensive expression and functional profile of differentially expressed miRNAs associated with chordoma. This profile may serve as a potential tool for biomarker and therapeutic target identification in patients with chordoma.

Knockdown of RRS1 by lentiviral-mediated RNAi promotes apoptosis and suppresses proliferation of human hepatocellular carcinoma cells

In recent years it was found that the synthesis and biological activity of ribosomes are closely associated with tumor cell growth, tumorigenesis, and malignant transformation. However, the role of regulator of ribosome synthesis 1 (RRS1) in hepatocellular carcinoma (HCC) has not yet been reported. In the present study, we aimed to examine the potential role of RRS1 in tumor cell growth by using a lentivirus-mediated RNA interference (RNAi) system in the HCC cell line SMMC-7721 in vitro. Compared with that of the negative control group (Lv-shCon), the mRNA and protein expression levels of RRS1 in SMMC-7721 cells transfected with Lv-shRRS1 were significantly decreased. Further experiments found that silencing of RRS1 gene expression in SMMC-7721 cells significantly suppressed cell proliferation, inhibited colony formation capacity, increased apoptosis and arrested cells in the G1 phase. These results suggest that the RRS1 gene plays a critical role in cell proliferation, colony formation, cell apoptosis and cell cycle distribution in human HCC cells, and that silencing of RRS1 by RNAi is a promising therapeutic approach for the treatment of HCC, and should be further developed.

miR-145 inhibits proliferation and migration of breast cancer cells by directly or indirectly regulating TGF-β1 expression

Studies have demonstrated low expression of miR-145 associated with cell proliferation and migration in a wide variety of tumors. Here, we studied the expression of miR-145 in relation to the occurrence and development of breast cancer. Total RNA from breast cancer tissue and corresponding adjacent normal tissue was extracted and used to detect miR-145 expression by quantitative real-time polymerase chain reaction (qRT-PCR). We also transfected breast cancer cells with hsa-miR-145 mimics, hsa-miR-145 inhibitor, mimics negative control (mimics NC) or inhibitor negative control (inhibitor NC). Cell proliferation was analyzed by colony formation assays and methyl thiazolyl tetrazolium assays. Cell proliferation in breast cancer cells was decreased after overexpression of miR-145 and increased following miR-145 suppression. Cell migration and invasion were assessed using Transwell and wound healing assays, respectively, and were also decreased after overexpression of miR-145 and increased after miR-145 suppression in breast cancer cells. Finally, western blot assays showed that overexpression of miR-145 inhibited expression of transforming growth factor-β1 (TGF-β1). Collectively, these data suggest that miR-145 may inhibit TGF-β1 protein expression which may in turn contribute to tumor formation.

Plasma and saliva miR-21 expression in colorectal cancer patients

MicroRNA-21 (miR-21) expression was quantified by real-time qRT-PCR in peripheral blood and saliva samples obtained from patients diagnosed with colorectal cancer (CRC) of varying degrees of malignancy and healthy volunteers. All patients had adenocarcinoma located in the distal colon at different stages. Significant differences were detected between the control group and the total experimental group of CRC patients (plasma, P = 0.0001; saliva, P = 5e-12). MiR-21 expression was also significantly different in certain subgroups of patients with CRC disease stages II-IV as compared to the control group. No correlation of miR-21 expression was found with regard to gender and age of patents. Also, there were no significant individual correlations and linear regression of miR-21 expression in the plasma and saliva. The estimated diagnostic sensitivity and specificity of miR-21 expression were respectively 65 and 85% in the plasma, and 97 and 91% in the saliva. Our data suggest that miR-21 in both the saliva and plasma could be a proper biomarker for CRC screening, although the saliva miR-21 expression test looks preferable due to its higher sensitivity, specificity, and technical simplicity.