Upregulation of miRNA-155 promotes tumour angiogenesis by targeting VHL and is associated with poor prognosis and triple-negative breast cancer. Oncogene. 2014;33:679-689. [PMID: 23353819 PMCID: PMC3925335 DOI: 10.1038/onc.2012.636]

MicroRNA-155 and its exosomal form: Small pieces in the gastrointestinal cancers puzzle

Gastrointestinal (GI) cancers are common cancers that are responsible for a large portion of global cancer fatalities. Due to this, there is a pressing need for innovative strategies to identify and treat GI cancers. MicroRNAs (miRNAs) are short ncRNAs that can be considered either cancer-causing or tumor-inhibiting molecules. MicroRNA-155, also known as miR-155, is a vital regulator in various cancer types. This miRNA has a carcinogenic role in a variety of gastrointestinal cancers, including pancreatic, colon, and gastric cancers. Since the abnormal production of miR-155 has been detected in various malignancies and has a correlation with increased mortality, it is a promising target for future therapeutic approaches. Moreover, exosomal miR-155 associated with tumors have significant functions in communicating between cells and establishing the microenvironment for cancer in GI cancers. Various types of genetic material, such as specifically miR-155 as well as proteins found in cancer-related exosomes, have the ability to be transmitted to other cells and have a function in the advancement of tumor. Therefore, it is critical to conduct a review that outlines the diverse functions of miR-155 in gastrointestinal malignancies. As a result, we present a current overview of the role of miR-155 in gastrointestinal cancers. Our research highlighted the role of miR-155 in GI cancers and covered critical issues in GI cancer such as pharmacologic inhibitors of miRNA-155, miRNA-155-assosiated circular RNAs, immune-related cells contain miRNA-155. Importantly, we discussed miRNA-155 in GI cancer resistance to chemotherapy, diagnosis and clinical trials. Furthermore, the function of miR-155 enclosed in exosomes that are released by cancer cells or tumor-associated macrophages is also covered.

The Overexpressed MicroRNAs miRs-182, 155, 493, 454, and U6 snRNA and Underexpressed let-7c, miR-328, and miR-451a as Potential Biomarkers in Invasive Breast Cancer and Their Clinicopathological Significance

INTRODUCTION

Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers.

METHODS

This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data.

RESULTS

Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations.

CONCLUSION

We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice.

Interplay between Wnt signaling molecules and exosomal miRNAs in breast cancer (Review)

Breast cancer (BC) is the most common malignancy in women worldwide. Wnt signaling is involved in tumorigenesis and cancer progression, and is closely associated with the characteristics of BC. Variation in the expression of exosomal microRNAs (miRNAs) modulates key cancer phenotypes, such as cellular proliferation, epithelial‑mesenchymal transition, metastatic potential, immune evasion and treatment resistance. The present review aimed to discuss the importance of Wnt signaling and exosomal miRNAs in regulating the occurrence and development of BC. In addition, the present review determined the crosstalk between Wnt signaling and exosomal miRNAs, and highlighted potential diagnostic biomarkers and therapeutic targets.

MiR-155-targeted IcosL controls tumor rejection

Elevated levels of miR-155 in solid and liquid malignancies correlate with aggressiveness of the disease. In this manuscript, we show that miR-155 targets transcripts encoding IcosL, the ligand for Inducible T-cell costimulator (Icos), thus impairing the ability of T cells to recognize and eliminate malignant cells. We specifically found that overexpression of miR-155 in B cells of Eµ-miR-155 mice causes loss of IcosL expression as they progress toward malignancy. Similarly, in mice where miR-155 expression is controlled by a Cre-Tet-OFF system, miR-155 induction led to malignant infiltrates lacking IcosL expression. Conversely, turning miR-155 OFF led to tumor regression and emergence of infiltrates composed of IcosL-positive B cells and Icos-positive T cells forming immunological synapses. Therefore, we next engineered malignant cells to express IcosL, in order to determine whether IcosL expression would increase tumor infiltration by cytotoxic T cells and reduce tumor progression. Indeed, overexpressing an IcosL-encoding cDNA in MC38 murine colon cancer cells before injection into syngeneic C57BL6 mice reduced tumor size and increased intratumor CD8+ T cell infiltration, that formed synapses with IcosL-expressing MC38 cells. Our results underscore the fact that by targeting IcosL transcripts, miR-155 impairs the infiltration of tumors by cytotoxic T cells, as well as the importance of IcosL on enhancing the immune response against malignant cells. These findings should lead to the development of more effective anticancer treatments based on maintaining, increasing, or restoring IcosL expression by malignant cells, along with impairing miR-155 activity.

MicroRNAs in Helicobacter pylori-infected gastric cancer: Function and clinical application

Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and it is associated with a combination of genetic, environmental, and microbial risk factors. Helicobacter pylori (H. pylori) is classified as a type I carcinogen, however, the exact regulatory mechanisms underlying H. pylori-induced GC are incompletely defined. MicroRNAs (miRNAs), one of small non-coding RNAs, negatively regulate gene expression through binding to their target genes. Dysregulation of miRNAs is crucial in human cancer. A noteworthy quantity of aberrant miRNAs induced by H. pylori through complex regulatory networks have been identified. These miRNAs substantially affect genetic instability, cell proliferation, apoptosis, invasion, metastasis, autophagy, chemoresistance, and the tumor microenvironment, leading to GC development and progression. Importantly, some H. pylori-associated miRNAs hold promise as therapeutic tools and biomarkers for GC prevention, diagnosis, and prognosis. Nonetheless, clinical application of miRNAs remains in its infancy with multiple issues, including sensitivity and specificity, stability, reliable delivery systems, and off-target effects. Additional research on the specific molecular mechanisms and more clinical data are still required. This review investigated the biogenesis, regulatory mechanisms, and functions of miRNAs in H. pylori-induced GC, offering novel insights into the potential clinical applications of miRNA-based therapeutics and biomarkers.

PI3K/AKT pathway as a pivotal regulator of epithelial-mesenchymal transition in lung tumor cells

Lung cancer, as the leading cause of cancer related deaths, is one of the main global health challenges. Despite various progresses in diagnostic and therapeutic methods, there is still a high rate of mortality among lung cancer patients, which can be related to the lack of clinical symptoms to differentiate lung cancer from the other chronic respiratory disorders in the early tumor stages. Most lung cancer patients are identified in advanced and metastatic tumor stages, which is associated with a poor prognosis. Therefore, it is necessary to investigate the molecular mechanisms involved in lung tumor progression and metastasis in order to introduce early diagnostic markers as well as therapeutic targets. Epithelial-mesenchymal transition (EMT) is considered as one of the main cellular mechanisms involved in lung tumor metastasis, during which tumor cells gain the metastatic ability by acquiring mesenchymal characteristics. Since, majority of the oncogenic signaling pathways exert their role in tumor cell invasion by inducing the EMT process, in the present review we discussed the role of PI3K/AKT signaling pathway in regulation of EMT process during lung tumor metastasis. It has been reported that the PI3K/AKT acts as an inducer of EMT process through the activation of EMT-specific transcription factors in lung tumor cells. MicroRNAs also exerted their inhibitory effects during EMT process by inhibition of PI3K/AKT pathway. This review can be an effective step towards introducing the PI3K/AKT pathway as a suitable therapeutic target to inhibit the EMT process and tumor metastasis in lung cancer patients.

MicroRNA-155 and exosomal microRNA-155: Small pieces in the cardiovascular diseases puzzle

MicroRNAs (miRs, miRNAs) are known to have a part in various human illnesses, such as those related to the heart. One particular miRNA, miR-155, has been extensively studied and has been found to be involved in hematopoietic lineage differentiation, immunity, viral infections, inflammation, as well as vascular remodeling. These processes have all been connected to cardiovascular diseases, including heart failure, diabetic heart disease, coronary artery disease, and abdominal aortic aneurysm. The impacts of miR-155 depend on the type of cell it is acting on and the specific target genes involved, resulting in different mechanisms of disease. Although, the exact part of miR-155 in cardiovascular illnesses is yet not fully comprehended, as some studies have shown it to promote the development of atherosclerosis while others have shown it to prevent it. As a result, to comprehend the underlying processes of miR-155 in cardiovascular disorders, further thorough study is required. It has been discovered that exosomes that could be absorbed by adjacent or distant cells, control post-transcriptional regulation of gene expression by focusing on mRNA. Exosomal miRNAs have been found to have a range of functions, including participating in inflammatory reactions, cell movement, growth, death, autophagy, as well as epithelial-mesenchymal transition. An increasing amount of research indicates that exosomal miRNAs are important for cardiovascular health and have a major role in the development of a number of cardiovascular disorders, including pulmonary hypertension, atherosclerosis, acute coronary syndrome, heart failure, and myocardial ischemia-reperfusion injury. Herein the role of miR-155 and its exosomal form in heart diseases are summarized.

Epigenetic deregulation in breast cancer microenvironment: Implications for tumor progression and therapeutic strategies

Breast cancer comprises a substantial proportion of cancer diagnoses in women and is a primary cause of cancer-related mortality. While hormone-responsive cases generally have a favorable prognosis, the aggressive nature of triple-negative breast cancer presents challenges, with intrinsic resistance to established treatments being a persistent issue. The complexity intensifies with the emergence of acquired resistance, further complicating the management of breast cancer. Epigenetic changes, encompassing DNA methylation, histone and RNA modifications, and non-coding RNAs, are acknowledged as crucial contributors to the heterogeneity of breast cancer. The unique epigenetic landscape harbored by each cellular component within the tumor microenvironment (TME) adds great diversity to the intricate regulations which influence therapeutic responses. The TME, a sophisticated ecosystem of cellular and non-cellular elements interacting with tumor cells, establishes an immunosuppressive microenvironment and fuels processes such as tumor growth, angiogenesis, and extracellular matrix remodeling. These factors contribute to challenging conditions in cancer treatment by fostering a hypoxic environment, inducing metabolic stress, and creating physical barriers to drug delivery. This article delves into the complex connections between breast cancer treatment response, underlying epigenetic changes, and vital interactions within the TME. To restore sensitivity to treatment, it emphasizes the need for combination therapies considering epigenetic changes specific to individual members of the TME. Recognizing the pivotal role of epigenetics in drug resistance and comprehending the specificities of breast TME is essential for devising more effective therapeutic strategies. The development of reliable biomarkers for patient stratification will facilitate tailored and precise treatment approaches.

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.

BRCA Mutations and MicroRNA Expression Patterns in the Peripheral Blood of Breast Cancer Patients

Breast cancer (BC) persists as the predominant malignancy globally, standing as the foremost cause of cancer-related mortality among women. Despite notable advancements in prevention and treatment, encompassing the incorporation of targeted immunotherapies, a continued imperative exists for the development of innovative methodologies. These methodologies would facilitate the identification of women at heightened risk, enhance the optimization of therapeutic approaches, and enable the vigilant monitoring of emergent treatment resistance. Circulating microRNAs (miRNAs), found either freely circulating in the bloodstream or encapsulated within extracellular vesicles, have exhibited substantial promise for diverse clinical applications. These applications range from diagnostic and prognostic assessments to predictive purposes. This study aimed to explore the potential associations between BRCA mutations and specific miRNAs (miR-21, miR-155, miR-126, and miR-200c) expression that are known to be dysregulated in BC patient samples. Our findings indicate a robust correlation between miRNA expression status and disease subtypes. We found a correlation between the expression status of miRNAs and distinct disease subtypes. Intriguingly, however, no significant associations were discerned between disease status, subtypes, or miRNA expression levels and the presence of BRCA mutations. To advance the validation of miRNAs as clinically relevant biomarkers, additional investigations within larger and meticulously selected patient cohorts are deemed imperative. These microRNA entities hold the potential to emerge as groundbreaking and readily accessible tools, poised for seamless integration into the landscape of clinical practice.

Circulating microRNA-155-3p levels predicts response to first line immunotherapy in patients with metastatic renal cell carcinoma

Predictive biomarkers of response to immune checkpoint-based therapies (ICI) remain a critically unmet need in the management of advanced renal cell carcinoma (RCC). The complex interplay of the tumour microenvironment (TME) and the circulating immune response has proven to be challenging to decipher. MicroRNAs have gained increasing attention for their role in post-transcriptional gene expression regulation, particularly because they can have immunomodulatory properties. We evaluated the presence of immune-specific extracellular vesicle (EV) microRNAs in the plasma of patients with metastatic RCC (mRCC) prior to initiation of ICI. We found significantly lower levels of microRNA155-3p (miR155) in responders to ICI, when compared to non-responders. This microRNA has unique immunomodulatory properties, thus providing potential biological rationale for our findings. Our results support further work in exploring microRNAs as potential biomarkers of response to immunotherapy.

MiR-155 promotes compensatory lung growth by inhibiting JARID2 activation of CD34+ endothelial progenitor cells

Bone marrow-derived CD34-positive (CD34+) endothelial progenitor cells (EPCs) has unique functions in the mechanism of compensatory lung growth (CLG). The content of this study is mainly to describe the effect of microRNA (miR)-155 in the mechanisms of EPCs and CLG. Our study found that transfection of miR-155 mimic could promote EPC proliferation, migration and tube formation, while transfection of miR-155 inhibitor had the opposite effect. It was also found that transfection of pc-JARID2 inhibited EPC proliferation, migration and tube formation, while transfection of si-JARID2 had the opposite effect. miR-155 can target and negatively regulate JARID2 expression. Overexpression of JARID2 weakened the promoting effects of miR-155 mimic on EPC proliferation, migration, and tubular formation, while silencing JARID2 weakened the inhibitory effects of miR-155 inhibitors on EPC proliferation, migration, and tubular formation. Transplantation of EPCs transfected with miR-155 mimic into the left lung model effectively increased lung volume, total alveolar number, diaphragm surface area, and lung endothelial cell number, while transplantation of EPCs co-transfected with miR-155 mimic and pc-JARID2 reversed this phenomenon. Overall, we found that miR-155 activates CD34+ EPC by targeting negative regulation of JARID2 and promotes CLG.

Role of Angiogenesis and Its Biomarkers in Development of Targeted Tumor Therapies

Angiogenesis plays a significant role in the human body, from wound healing to tumor progression. "Angiogenic switch" indicates a time-restricted event where the imbalance between pro- and antiangiogenic factors results in the transition from prevascular hyperplasia to outgrowing vascularized tumor, which eventually leads to the malignant cancer progression. In the last decade, molecular players, i.e., angiogenic biomarkers and underlying molecular pathways involved in tumorigenesis, have been intensely investigated. Disrupting the initiation and halting the progression of angiogenesis by targeting these biomarkers and molecular pathways has been considered as a potential treatment approach for tumor angiogenesis. This review discusses the currently known biomarkers and available antiangiogenic therapies in cancer, i.e., monoclonal antibodies, aptamers, small molecular inhibitors, miRNAs, siRNAs, angiostatin, endostatin, and melatonin analogues, either approved by the U.S. Food and Drug Administration or currently under clinical and preclinical investigations.

An Intricate Relationship Between miR-155-5p Expression and Oxidative Stress in Bladder Cancer Patients Treated with Calmette-Guerin Immunotherapy

Treatment failure after intravesical instillation of Bacillus Calmette-Guerin immunotherapy (BCG) for non-muscle-invasive bladder cancer (BCa) occurs frequently. The exact effects of BCG on cellular redox status and gene expression remain unclear. We assessed oxidative stress biomarkers and changes in miR-155-5p expression in response to BCG. Twenty-seven patients with BCa were recruited for measuring tissue and serum malondialdehyde (MDA) and total antioxidant capacity (TAC) levels, and tissue expression of miR-155-5p at two-time points: pre and 6 weeks post BCG. Recurrence of BCa was observed after 20 months. R statistical software was used for paired comparisons of biomarkers, as well as the correlation between variables. Significant increases in TAC were observed after BCG (P= <0.001). Tissue MDA levels were significantly reduced (P= 0.003). miR-155-5p was slightly overexpressed after BCG (median fold change=1.3, P=0.25). At the 20-month follow-up, it was observed that improved MDA and TAC changes were significant only in patients without recurrence of BCa. In patients with recurrence, the pre-treatment expression ratio of miR-155-p5 was positively correlated with TAC (R=0.63, P= 0.032) and negatively correlated with MDA (R=-0.72, P=0.037). In patients with recurrence of BCa pre-treatment miR-155-5p showed negative correlation with its expression changes after BCG (R=-0.78, P=0.004). Conclusions: Treatment with BCG has some beneficial effects on the oxidative stress status, which is probably modulated by miR-155-5p. A well-controlled oxidative balance may enhance overall survival of BCa. Considering its high recurrence rate, our pilot experiment can open a window toward better management of patients with BCa.

Impact of three miRNA signature as potential diagnostic marker for triple negative breast cancer patients

Breast cancer is a highly aggressive type of cancer and has several subtypes, including triple-negative breast cancer (TNBC), which accounts for 25% of morbidity related to breast cancer. miRNAs are small non-coding RNA molecules that regulate 60% of human genes. Dysregulated expression of miRNA in liquid biopsy of TNBC patients has the potential as a minimally invasive diagnostic biomarker. The Association of miRNA with TNBC was evaluated using in-silico analysis. Highly enriched miRNAs were selected for functional analysis to evaluate the role of miRNA in the progression of TNBC. The qRT-PCR-based expression analysis of miRNA was performed in 190 serum samples (139 TNBC and 51 healthy). Revealed the elevated expression of miRNA-155 and miRNA-21 in TNBC compared to control samples (P < 0.0001), while miRNA-205 was significantly downregulated in TNBC (P < 0.0001). The combined diagnostic value of the miRNA-205, miRNA-155 and miRNA-21 in cohort-I, cohort-II, and cohort-III was AUC of 96.1% (P < 0.0001), 94.9% (P < 0.0001), and 97.1% (P < 0.0001), respectively. Our study revealed that dysregulated expression of miRNA could be used as an independent indicator for discriminating TNBC from healthy patients. In addition, the combined predictive value of miRNA-205 + miRNA - 155 + miRNA-21 has higher AUC, sensitivity, and specificity in the diagnosis of TNBC in all three cohorts.

Construction of electrochemical biosensors based on MoSe2@1T-MoS2 heterojunction for the sensitive and rapid detection of miRNA-155 biomarker in breast cancer

MiRNA-155 is a typical biomarker for breast cancer. Since its low concentration in the physiological environment and the limitations of conventional miRNA detection methods like Northern imprinting and RT-qPCR, convenient, real-time, and rapid detection methods are urgently needed. In this work, an electrochemical biosensor was constructed based on the flower-like MoSe2@1T-MoS2 heterojunction electrode material and specific RNA recognition probes, which can realize the rapid determination of miRNA-155 content with a wide detection range from 1 fM to 1 nM and a limit of detection (LOD) as low as 0.34 fM. Furthermore, the contents of miRNA-155 in blood samples of tumor-bearing mice and normal mice were measured as 724.93 pM and 21.42 pM, respectively by this biosensor, demonstrating its strong identification ability and miRNA-155 can be regarded as an ideal diagnostic marker. On this basis, a portable sensor platform was designed for on-site detection simulation and showed good recovery efficiency from 95.80% to 98.69%. Meanwhile, compared with the standard detection method RT-qPCR, the accuracy and reliability of the biosensor were verified, indicating that the biosensor has the potential to provide point-of-care testing (POCT) for the early diagnosis of breast cancer.

MicroRNA-155 downregulates long noncoding RNA prostate cancer-associated transcript 29 in hepatocellular carcinoma to suppress cancer cell invasion and migration

Long noncoding RNA (lncRNA) prostate cancer-associated transcript 29 (PCAT29) is known to suppress several cancers, but its participation in hepatocellular carcinoma (HCC) remains elusive. This study tried to explore PCAT29 function in HCC. In this study, a total of 62 HCC patients were enrolled. Tissue samples were collected from all 62 patients to isolate RNA samples. Quantitative reverse transcription polymerase chain reaction was applied for the expression analysis of PCAT29 and microRNA-155 (miR-155) in these tissue samples. The 62 HCC patients were followed up for 5 years to explore the prognostic value of PCAT29 for HCC. Correlations were analyzed using linear regression. IntaRNA 2.0 was used to predict the interaction between PCAT29 and miR-155. The role of PCAT29 and miR-155 in regulating HCC cell invasion and migration was evaluated by Transwell assay. We found that PCAT29 expression was downregulated in HCC and miR-155 expression was upregulated in HCC compared to nontumor samples (p < 0.001). Downregulation of PCAT29 was found to be closely associated with poor survival of HCC patients. MiR-155 was inversely correlated with PCAT29. It was predicted that miR-155 could target PCAT29. In HCC cells, miR-155 overexpression resulted in reduced PCAT29 expression (p < 0.05). MiR-155 counteracted the inhibitory effects of PCAT29 overexpression on HCC cell migration and invasion. These results suggest that PCAT29 may be a potential prognostic biomarker and a novel therapeutic target for treating HCC.

miRNAs in the prognosis of triple-negative breast cancer: A review

Triple-Negative Breast Cancer (TNBC) is a highly aggressive and invasive type of breast cancer (BC) with high mortality rate wherein effective target medicaments are lacking. It is a very heterogeneous group with several subtypes that account for 10-20% of cancer among women globally, being negative for three most important receptors (estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)), with an early and high recurrence resulting in poor survival rate. Therefore, a more thorough knowledge on carcinogenesis of TNBC is required for the development of personalized treatment options. miRNAs can either promote or suppress tumorigenesis and have been linked to a number of features of cancer progression, including proliferation, metastasis, apoptosis, and epithelial-mesenchymal transition (EMT). Recent miRNA research shows that there is great potential for the development of novel biomarkers as they have emerged as drivers of tumorigenesis and provide opportunities to target various components involved in TNBC, thus helping to solve this difficult-to-treat disease. In this review, we summarize the most relevant miRNAs that play an essential role in TNBC biology. Their role with regard to molecular mechanisms underlying TNBC progression has been discussed, and their potential use as therapeutic or prognostic markers to unravel the intricacy of TNBC based on the pieces of evidence obtained from various works of literature has been briefly addressed.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

The anticancer mechanism of action of selected polyphenols in triple-negative breast cancer (TNBC)

Breast cancer is a leadingcause of cancer-related deaths in women globally, with triple-negative breast cancer (TNBC) being an aggressive subtype that lacks targeted therapies and is associated with a poor prognosis. Polyphenols, naturally occurring compounds in plants, have been investigated as a potential therapeutic strategy for TNBC. This review provides an overview of the anticancer effects of polyphenols in TNBC and their mechanisms of action. Several polyphenols, including resveratrol, quercetin, kaempferol, genistein, epigallocatechin-3-gallate, apigenin, fisetin, hesperetin and luteolin, have been shown to inhibit TNBC cell proliferation, induce cell cycle arrest, promote apoptosis, and suppress migration/invasion in preclinical models. The molecular mechanisms underlying their anticancer effects involve the modulation of several signalling pathways, such as PI3K/Akt, MAPK, STATT, and NF-κB pathways. Polyphenols also exhibit synergistic effects with chemotherapy drugs, making them promising candidates for combination therapy. The review also highlights clinical trials investigating the potential use of polyphenols, individually or in combination therapy, against breast cancer. This review deepens the under-standing of the mechanism of action of respective polyphenols and provides valuable insights into the potential use of polyphenols as a therapeutic strategy for TNBC, and lays the groundwork for future research in this area.

Construction of a Matrix Cancer-Associated Fibroblast Signature Gene-Based Risk Prognostic Signature for Directing Immunotherapy in Patients with Breast Cancer Using Single-Cell Analysis and Machine Learning

Cancer-associated fibroblasts (CAFs) are heterogeneous constituents of the tumor microenvironment involved in the tumorigenesis, progression, and therapeutic responses of tumors. This study identified four distinct CAF subtypes of breast cancer (BRCA) using single-cell RNA sequencing (RNA-seq) data. Of these, matrix CAFs (mCAFs) were significantly associated with tumor matrix remodeling and strongly correlated with the transforming growth factor (TGF)-β signaling pathway. Consensus clustering of The Cancer Genome Atlas (TCGA) BRCA dataset using mCAF single-cell characteristic gene signatures segregated samples into high-fibrotic and low-fibrotic groups. Patients in the high-fibrotic group exhibited a significantly poor prognosis. A weighted gene co-expression network analysis and univariate Cox analysis of bulk RNA-seq data revealed 17 differential genes with prognostic values. The mCAF risk prognosis signature (mRPS) was developed using 10 machine learning algorithms. The clinical outcome predictive accuracy of the mRPS was higher than that of the conventional TNM staging system. mRPS was correlated with the infiltration level of anti-tumor effector immune cells. Based on consensus prognostic genes, BRCA samples were classified into the following two subtypes using six machine learning algorithms (accuracy > 90%): interferon (IFN)-γ-dominant (immune C2) and TGF-β-dominant (immune C6) subtypes. Patients with mRPS downregulation were associated with improved prognosis, suggesting that they can potentially benefit from immunotherapy. Thus, the mRPS model can stably predict BRCA prognosis, reflect the local immune status of the tumor, and aid clinical decisions on tumor immunotherapy.

Unlocking the Potential of Circulating miRNAs in the Breast Cancer Neoadjuvant Setting: A Systematic Review and Meta-Analysis

The potential role of circulating microRNAs (miRNAs) as biomarkers in breast cancer (BC) management has been widely reported. However, the numerous discrepancies between studies in this regard hinders the implementation of circulating miRNAs in routine clinical practice. In the context of BC patients undergoing neoadjuvant chemotherapy (NAC), the possibility of predicting NAC response may lead to prognostic improvements by individualizing post-neoadjuvant therapy. In this context, the present meta-analysis aims to clarify circulating miRNAs' predictive role with respect to NAC response among BC patients. We conducted a comprehensive literature search on five medical databases until 16 February 2023. We pooled the effect sizes of each study by applying a random-effects model. Cochran's Q test (p-level of significance set at 0.05) scores and I² values were assessed to determine between-study heterogeneity. The PROBAST (Prediction Model Risk of Bias Assessment Tool) tool was used to evaluate the selected studies' risk of bias. Overall, our findings support the hypothesis that circulating miRNAs, specifically miR-21-5p and miR-155-5p, may act as predictive biomarkers in the neoadjuvant setting among BC patients. However, due to the limited number of studies included in this meta-analysis and the high degrees of clinical and statistical heterogeneity, further research is required to confirm the predictive power of circulating miR-21-5p and miR-155-5p.

Non-coding RNA's prevalence as biomarkers for prognostic, diagnostic, and clinical utility in breast cancer

Noncoding RNAs (ncRNAs), which make up a significant portion of the mammalian transcriptome and plays crucial regulatory roles in expression of genes and other biological processes, have recently been found. The most extensively researched of the sncRNAs, microRNAs (miRNAs), have been characterized in terms of their synthesis, roles, and significance in the tumor development. Its crucial function in the stem cell regulation, another class of sncRNAs known as aspirRNAs, has attracted attention in cancer research. The investigations have shown that long non-coding RNAs have a crucial role in controlling developmental stages, such as mammary gland development. Additionally, it has been discovered that lncRNA dysregulation precedes the development of several malignancies, including breast cancer. The functions of sncRNAs (including miRNAs and piRNAs) and lncRNAs in the onset and development of the breast cancer are described in this study. Additionally, future perspectives of various ncRNA-based diagnostic, prognostic, and therapeutic approaches also discussed.

Programming inactive RNA-binding small molecules into bioactive degraders

Target occupancy is often insufficient to elicit biological activity, particularly for RNA, compounded by the longstanding challenges surrounding the molecular recognition of RNA structures by small molecules. Here we studied molecular recognition patterns between a natural-product-inspired small-molecule collection and three-dimensionally folded RNA structures. Mapping these interaction landscapes across the human transcriptome defined structure-activity relationships. Although RNA-binding compounds that bind to functional sites were expected to elicit a biological response, most identified interactions were predicted to be biologically inert as they bind elsewhere. We reasoned that, for such cases, an alternative strategy to modulate RNA biology is to cleave the target through a ribonuclease-targeting chimera, where an RNA-binding molecule is appended to a heterocycle that binds to and locally activates RNase L1. Overlay of the substrate specificity for RNase L with the binding landscape of small molecules revealed many favourable candidate binders that might be bioactive when converted into degraders. We provide a proof of concept, designing selective degraders for the precursor to the disease-associated microRNA-155 (pre-miR-155), JUN mRNA and MYC mRNA. Thus, small-molecule RNA-targeted degradation can be leveraged to convert strong, yet inactive, binding interactions into potent and specific modulators of RNA function.

Breast Cancer Therapeutics and Hippo Signaling Pathway: Novel MicroRNA-Gene-Protein Interaction Networks

The Hippo signaling pathway is a master regulator of development, cell proliferation, and apoptosis in particular, and it plays an important role in tissue regeneration, controlling organ size, and cancer suppression. Dysregulation of the Hippo signaling pathway has been implicated in breast cancer, a highly prevalent cancer affecting 1 out of every 15 women worldwide. While the Hippo signaling pathway inhibitors are available, they are suboptimal, for example, due to chemoresistance, mutation, and signal leakage. Inadequate knowledge about the Hippo pathway connections and their regulators limits our ability to uncover novel molecular targets for drug development. We report here novel microRNA (miRNA)-gene and protein-protein interaction networks in the Hippo signaling pathway. We employed the GSE miRNA dataset for the present study. The GSE57897 dataset was normalized and searched for differentially expressed miRNAs, and their targets were searched using the miRWalk2.0 tool. From the upregulated miRNAs, we observed that the hsa-miR-205-5p forms the biggest cluster and targets four genes involved in the Hippo signaling pathway. Interestingly, we found a novel connection between two Hippo signaling pathway proteins, angiomotin (AMOT) and mothers against decapentaplegic homolog 4 (SMAD4). From the downregulated miRNAs, hsa-miR-16-5p, hsa-miR-7g-5p, hsa-miR-141-3p, hsa-miR-103a-3p, hsa-miR-21-5p, and hsa-miR-200c-3p, target genes were present in the pathway. We found that PTEN, EP300, and BTRC were important cancer-inhibiting proteins, form hubs, and their genes interact with downregulating miRNAs. We suggest that targeting proteins from these newly unraveled networks in the Hippo signaling pathway and further research on the interaction of hub-forming cancer-inhibiting proteins can open up new avenues for next-generation breast cancer therapeutics.

Targeting AXL in Mesothelioma: from functional characterization to clinical implication

Malignant pleural mesothelioma (MM) is a highly aggressive and lethal cancer with a poor survival rate. Current treatment approaches primarily rely on chemotherapy and radiation, but their effectiveness is limited. Consequently, there is an urgent need for alternative treatment strategies, a comprehensive understanding of the molecular mechanisms underlying MM, and the identification of potential therapeutic targets. Extensive studies over the past decade have emphasized the role of Axl in driving tumor development and metastasis, while high levels of Axl expression have been associated with immune evasion, drug resistance, and reduced patient survival in various cancer types. Ongoing clinical trials are investigating the efficacy of Axl inhibitors for different cancers. However, the precise role of Axl in MM progression, development, and metastasis, as well as its regulatory mechanisms within MM, remain inadequately understood. This review aims to comprehensively investigate the involvement of Axl in MM. We discuss Axl role in MM progression, development, and metastasis, along with its specific regulatory mechanisms. Additionally, we examined the Axl associated signaling pathways, the relationship between Axl and immune evasion, and the clinical implications of Axl for MM treatment. Furthermore, we discussed the potential utility of liquid biopsy as a non-invasive diagnostic technique for early detection of Axl in MM. Lastly, we evaluated the potential of a microRNA signature that targets Axl. By consolidating existing knowledge and identifying research gaps, this review contributes to a better understanding of Axl's role in MM and sets the stage for future investigations and the development of effective therapeutic interventions.

MicroRNA-155-5p, Reduced by Curcumin-Re-Expressed Hypermethylated BRCA1, Is a Molecular Biomarker for Cancer Risk in BRCA1-methylation Carriers

Constitutional BRCA1-methylation is a cancer risk factor for breast (BC) and ovarian (OC) cancer. MiR-155, regulated by BRCA1, is a multifunctional microRNA that plays a crucial role in the immune system. The present study assessed the modulation of miR-155-5p expression in peripheral white blood cells (WBCs) of BC and OC patients and cancer-free (CF) BRCA1-methylation female carriers. Additionally, we investigated the potential of curcumin to suppress miR-155-5p in BRCA1-deficient breast cancer cell lines. MiR-155-5p expression was measured using a stem-loop RT-qPCR method. Gene expression levels were determined using qRT-PCR and immunoblotting. MiR-155-5p was more highly expressed in the BRCA1-hypermethylated HCC-38 and UACC-3199 BC cell lines than in the BRCA1-mutated (HCC-1937) and WT BRCA1 (MDA-MB-321) cell lines. Curcumin suppressed miR-155-5p in the HCC-38 cells but not in the HCC-1937 cells via the re-expression of BRCA1. Elevated levels of miR-155-5p were detected in patients with non-aggressive and localized breast tumors and in patients with late-stage aggressive ovarian tumors, as well as in CF BRCA1-methylation carriers. Notably, IL2RG levels were reduced in the OC and CF groups but not in the BC group. Together, our findings suggest opposing effects of WBC miR-155-5p, according to the cell and cancer type. In addition, the results point to miR-155-5p as a candidate biomarker of cancer risk among CF-BRCA1-methylation carriers.

Novel insights into DNA methylation-based epigenetic regulation of breast tumor angiogenesis

Breast tumors are highly vascularized and dependent on angiogenesis for growth, progression and metastasis. Like other solid tumors, vasculature in breast tumors also display leaky and tortuous phenotype and hence inhibit immune cell infiltration, show reduced efficacy to anticancer drugs and radiotherapy. Epigenetic reprogramming including significant alterations in DNA methylation in tumor and stromal cells generate an imbalance in expression of pro- and anti-angiogenic factors and subsequently lead to disordered angiogenesis. Hence, understanding DNA methylation-based regulation of angiogenesis in breast tumors may open new avenues for designing therapeutic targets. Our present review manuscript summarized contemporary knowledge of influence of DNA methylation in regulating angiogenesis. Further, we identified novel set of pro-angiogenic genes enriched in endothelial cells which are coregulated with DNMT isoforms in breast tumors and harboring CpG islands. Our analysis revealed promoters of pro-angiogenic genes were hypomethylated and anti-angiogenic genes were hypermethylated in tumors and further reflected on their expression patterns. Interestingly, promoter DNA methylation intensities of novel set of pro-angiogenic genes significantly correlated to patient survival outcome.

The Diagnostic and Prognostic Value of miR-155 in Cancers: An Updated Meta-analysis

BACKGROUND

MicroRNA-155 has been discussed as a biomarker in cancer diagnosis and prognosis. Although relevant studies have been published, the role of microRNA-155 remains uncertain because of insufficient data.

METHODS

We conducted a literature search in PubMed, Embase, and Web of Science databases to obtain relevant articles and extract data to evaluate the role of microRNA-155 in cancer diagnosis and prognosis.

RESULTS

The pooled results showed that microRNA-155 presented a remarkable diagnostic value in cancers (area under the curve = 0.90, 95% confidence interval (CI 0.87-0.92; sensitivity = 0.83, 95% CI 0.79-0.87; specificity = 0.83, 95% CI 0.80-0.86), which was maintained in the subgroups stratified by ethnicity (Asian and Caucasian), cancer types (breast cancer, lung cancer, hepatocellular carcinoma, leukemia, and pancreatic ductal adenocarcinoma), sample types (plasma, serum, tissue), and sample size (n >100 and n <100). In prognosis, a combined hazard ratio (HR) showed that microRNA-155 was significantly associated with poor overall survival (HR = 1.38, 95% CI 1.25-1.54) and recurrence-free survival (HR = 2.13, 95% CI 1.65-2.76), and was boundary significant with poor progression-free survival (HR = 1.20, 95% CI 1.00-1.44), but not significant with disease-free survival (HR = 1.14, 95% CI 0.70-1.85). Subgroup analyses in overall survival showed that microRNA-155 was associated with poor overall survival in the subgroups stratified by ethnicity and sample size. However, the significant association was maintained in cancer types subgroups of leukemia, lung cancer, and oral squamous cell carcinoma, but not in colorectal cancer, hepatocellular carcinoma, and breast cancer, and was maintained in sample types subgroups of bone marrow and tissue, but not in plasma and serum.

CONCLUSIONS

Results from this meta-analysis demonstrated that microRNA-155 was a valuable biomarker in cancer diagnosis and prognosis.

Exosomal miRNAs as novel avenues for breast cancer treatment

Breast cancer is the most commonly diagnosed cancer and a leading cause of death in women worldwide. It is a heterogeneous disease, as shown by the gene expression profiles of breast cancer samples. It begins in milk-producing ducts, with a high degree of diversity between and within tumors, as well as among cancer-bearing individuals. The enhanced prevalence of breast cancer is influenced by various hormonal, lifestyle, and environmental factors, and very early onset of the disease correlates strongly with the risk of local and distant recurrence. Many subtypes are difficult to treat with conventional therapeutic modalities, and therefore, optimal management and early diagnosis are the first steps to minimizing the mortality linked with breast cancer. The use of newer methods of nanotechnology extends beyond the concept of synthesizing drug delivery mechanisms into the creation of new therapeutics, such as delivering chemotherapeutics with nanomaterial properties. Exosomes, a class of nanovesicles, are emerging as novel tools for deciphering the patient-specific proteins and biomarkers across different disease models, including breast cancer. In this review, we address the role of exosomal miRNA in breast cancer diagnosis and treatment.

Therapeutic Delivery of Tumor Suppressor miRNAs for Breast Cancer Treatment

The death rate from breast cancer (BC) has dropped due to early detection and sophisticated therapeutic options, yet drug resistance and relapse remain barriers to effective, systematic treatment. Multiple mechanisms underlying miRNAs appear crucial in practically every aspect of cancer progression, including carcinogenesis, metastasis, and drug resistance, as evidenced by the elucidation of drug resistance. Non-coding RNAs called microRNAs (miRNAs) attach to complementary messenger RNAs and degrade them to inhibit the expression and translation to proteins. Evidence suggests that miRNAs play a vital role in developing numerous diseases, including cancer. They affect genes critical for cellular differentiation, proliferation, apoptosis, and metabolism. Recently studies have demonstrated that miRNAs serve as valuable biomarkers for BC. The contrast in the expression of miRNAs in normal tissue cells and tumors suggest that miRNAs are involved in breast cancer. The important aspect behind cancer etiology is the deregulation of miRNAs that can specifically influence cellular physiology. The main objective of this review is to emphasize the role and therapeutic capacity of tumor suppressor miRNAs in BC and the advancement in the delivery system that can deliver miRNAs specifically to cancerous cells. Various approaches are used to deliver these miRNAs to the cancer cells with the help of carrier molecules, like nanoparticles, poly D, L-lactic-co-glycolic acid (PLGA) particles, PEI polymers, modified extracellular vesicles, dendrimers, and liposomes. Additionally, we discuss advanced strategies of TS miRNA delivery techniques such as viral delivery, self-assembled RNA-triple-helix hydrogel drug delivery systems, and hyaluronic acid/protamine sulfate inter-polyelectrolyte complexes. Subsequently, we discuss challenges and prospects on TS miRNA therapeutic delivery in BC management so that miRNAs will become a routine technique in developing individualized patient profiles.

The role of next-generation sequencing in the examination of signaling genes in Brca1/2-negative breast cancer cases

INTRODUCTION

Breast cancer is the most prevalent malignancy in women worldwide. Although pathogenic variants in the BRCA1/2 genes are responsible for the majority of hereditary breast cancer cases, a substantial proportion of patients are negative for pathogenic variations in these genes. In cancers, the signal transduction pathways of the cell are usually affected first. Therefore, this study aimed to detect and classified genetic variations in non-BRCA signaling genes and investigate the underlying genetic causes of susceptibility to breast cancer.

METHODS

Ninety-six patients without pathogenic variants in the BRCA1/2 genes who met the inclusion criteria were enrolled in the study, and 34 genes were analyzed using next-generation sequencing (NGS) for genetic analysis.

RESULTS

Based on the ClinVar database or American College of Medical Genetics criteria, a total of 55 variants of 16 genes were detected in 43 (44.8%) of the 96 patients included in the study. The pathogenic variants were found in the TP53, CHEK2, and RET genes, whereas the likely pathogenic variants were found in the FGFR1, FGFR3, EGFR, and NOTCH1 genes.

CONCLUSION

The examination of signaling genes in patients who met the established criteria for hereditary breast cancer but were negative for BRCA1/2 pathogenic variants provided additional information for approximately 8% of the families. The results of the present study suggest that NGS is a powerful tool for investigating the underlying genetic causes of occurrence and progression of breast cancer.

The various role of microRNAs in breast cancer angiogenesis, with a special focus on novel miRNA-based delivery strategies

After skin malignancy, breast cancer is the most widely recognized cancer detected in women in the United States. Breast cancer (BCa) can happen in all kinds of people, but it's much more common in women. One in four cases of cancer and one in six deaths due to cancer are related to breast cancer. Angiogenesis is an essential factor in the growth of tumors and metastases in various malignancies. An expanded level of angiogenesis is related to diminished endurance in BCa patients. This function assumes a fundamental part inside the human body, from the beginning phases of life to dangerous malignancy. Various factors, referred to as angiogenic factors, work to make a new capillary. Expanding proof demonstrates that angiogenesis is managed by microRNAs (miRNAs), which are small non-coding RNA with 19-25 nucleotides. MiRNA is a post-transcriptional regulator of gene expression that controls many critical biological processes. Endothelial miRNAs, referred to as angiomiRs, are probably concerned with tumor improvement and angiogenesis via regulation of pro-and anti-angiogenic factors. In this article, we reviewed therapeutic functions of miRNAs in BCa angiogenesis, several novel delivery carriers for miRNA-based therapeutics, as well as CRISPR/Cas9 as a targeted therapy in breast cancer.

VHL tumor suppressor as a novel potential candidate biomarker in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of endocrine cancer, with an increasing incidence worldwide. The treatment of PTC is currently the subject of clinical controversy, making it critically important to identify molecular markers that would help improve the risk stratification of PTC patients and optimize the therapeutic approach. The VHL tumor suppressor gene has been implicated in tumorigenesis of various types of carcinoma and linked with their aggressive biological behavior. The role of VHL in the origin and development of PTC has only recently begun to be revealed. In this narrative review we attempt to summarize the existing knowledge that implicates VHL in PTC pathogenesis and to outline its potential significance as a candidate molecular biomarker for the grouping of PTC patients into high and low risk groups.

MiRNAs Overexpression and Their Role in Breast Cancer: Implications for Cancer Therapeutics

MicroRNAs have a plethora of roles in various biological processes in the cells and most human cancers have been shown to be associated with dysregulation of the expression of miRNA genes. MiRNA biogenesis involves two alternative pathways, the canonical pathway which requires the successful cooperation of various proteins forming the miRNA-inducing silencing complex (miRISC), and the non-canonical pathway, such as the mirtrons, simtrons, or agotrons pathway, which bypasses and deviates from specific steps in the canonical pathway. Mature miRNAs are secreted from cells and circulated in the body bound to argonaute 2 (AGO2) and miRISC or transported in vesicles. These miRNAs may regulate their downstream target genes via positive or negative regulation through different molecular mechanisms. This review focuses on the role and mechanisms of miRNAs in different stages of breast cancer progression, including breast cancer stem cell formation, breast cancer initiation, invasion, and metastasis as well as angiogenesis. The design, chemical modifications, and therapeutic applications of synthetic anti-sense miRNA oligonucleotides and RNA mimics are also discussed in detail. The strategies for systemic delivery and local targeted delivery of the antisense miRNAs encompass the use of polymeric and liposomal nanoparticles, inorganic nanoparticles, extracellular vesicles, as well as viral vectors and viruslike particles (VLPs). Although several miRNAs have been identified as good candidates for the design of antisense and other synthetic modified oligonucleotides in targeting breast cancer, further efforts are still needed to study the most optimal delivery method in order to drive the research beyond preclinical studies.

The miR-34a-5p-c-MYC-CHK1/CHK2 Axis Counteracts Cancer Stem Cell-Like Properties and Enhances Radiosensitivity in Hepatocellular Cancer Through Repression of the DNA Damage Response

Radiotherapy has become an increasingly widespread modality for treating hepatocellular cancer (HCC); however, the development of radioresistance significantly limits its effectiveness and invariably leads to tumor recurrence. Cancer stem cell (CSC) theory offers a potential explanation for tumor relapse and radioresistance, but the underlying mechanism remains unknown. Herein we investigate the role of miRNA in molecular regulation of stemness and radioresistance in HCC. Two HCC radiation-resistant cell lines (Huh7-RR and SMMC-7721-RR) were established by selecting the radioresistant subpopulation from HCC cells via clonogenic survival assays. MiRNA Sequencing was used to identify potential radiosensitivity involved miRNA in HCC-RR cells. Xenograft tumor mouse model was established for in vivo study. CSC properties were assessed using sphere formation assay and side population (SP) cells analysis. We found that miR-34a-5p was significantly downregulated in HCC-RR cells. Overexpression of miR-34a-5p counteracts CSC properties and enhances radiosensitivity in HCC. Mechanistic investigation revealed that c-MYC is the direct target of miR-34a-5p. Overexpression of miR-34a-5p reversed c-MYC-induced radioresistance. Moreover, we found that the specific molecular mechanism was that c-MYC activated CHK1 and CHK2, which are two key DNA damage checkpoint kinases, and facilitated the DNA damage response to radiation. Repression of the miR-34a-5p-cMYC-CHK1/CHK2 axis contributes to the acquisition of radioresistance in HCC cells. In summary, the miR-34a-5p-c-MYC-CHK1/CHK2 axis counteracts cancer stem cell-like properties and enhances radiosensitivity in hepatocellular cancer through repression of the DNA damage response.

The Role of miRNAs in the Prognosis of Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

Breast cancer is one of the most common malignancies among women around the world. The basal or triple-negative subtype (TNBC) is a heterogeneous group of tumors, characterized by its aggressive and metastatic nature, with low survival and worse prognosis. Research on genetic biomarkers, such as microRNAs (miRs) in TNBC, demonstrate their relevance in the prognosis of the disease. Therefore, the objective of this research was to verify the role of miRs in the prognosis of TNBC. A search was carried out in the PubMed (MEDLINE), Web of Science, and Scopus databases, with articles in the English language from 2010 to 2022. Only articles that analyzed the role of miRNAs in the prognosis of TNBC and that met the criteria of the MOOSE method were included. For the preparation and planning of this systematic review, a PRISMA checklist and the MOOSE method were used. The Newcastle-Ottawa Scale was used to analyze the quality of the included studies. The excluded criteria considered were: (1) studies that presented duplication in the databases; (2) reviews of the literature, clinical case reports, meta-analyses, conference abstracts, letters to the editor, theses, dissertations, and book chapters; (3) studies that stratified only women diagnosed with other subtypes of breast cancer subtypes; (4) experiments without a control or comparison group. After the bibliographic survey of the 2.274 articles found, 43 articles met the inclusion criteria, totaling 5421 patients with TNBC analyzed for this review. Six miRs (miR-155, miR-21, miR-27a/b/, miR-374a/b, miR-30a/c/e, and miR-301a) were included in the meta-analysis. A low expression of miR-155 was associated with reduced overall survival (OS) (HR: 0.68, 95% CI: 0.58-0.81). A high expression of miR-21 was a predictor of OS reduction (HR: 2.56; 95% CI: 1.49-4.40). In addition, high levels of miR-27a/b and miR-301a/b were associated with lower OS, while the decreased expression levels of miR-30 and miR-374a/b were associated with worse relapse-free survival (RFS) and shorter disease-free survival (DFS), respectively. The present study revealed that miRs play essential roles in the development of metastases, in addition to acting as suppressors of the disease, thus improving the prognosis of TNBC. However, the clinical application of these findings has not yet been investigated.

Predicting multiple types of miRNA-disease associations using adaptive weighted nonnegative tensor factorization with self-paced learning and hypergraph regularization

More and more evidence indicates that the dysregulations of microRNAs (miRNAs) lead to diseases through various kinds of underlying mechanisms. Identifying the multiple types of disease-related miRNAs plays an important role in studying the molecular mechanism of miRNAs in diseases. Moreover, compared with traditional biological experiments, computational models are time-saving and cost-minimized. However, most tensor-based computational models still face three main challenges: (i) easy to fall into bad local minima; (ii) preservation of high-order relations; (iii) false-negative samples. To this end, we propose a novel tensor completion framework integrating self-paced learning, hypergraph regularization and adaptive weight tensor into nonnegative tensor factorization, called SPLDHyperAWNTF, for the discovery of potential multiple types of miRNA-disease associations. We first combine self-paced learning with nonnegative tensor factorization to effectively alleviate the model from falling into bad local minima. Then, hypergraphs for miRNAs and diseases are constructed, and hypergraph regularization is used to preserve the high-order complex relations of these hypergraphs. Finally, we innovatively introduce adaptive weight tensor, which can effectively alleviate the impact of false-negative samples on the prediction performance. The average results of 5-fold and 10-fold cross-validation on four datasets show that SPLDHyperAWNTF can achieve better prediction performance than baseline models in terms of Top-1 precision, Top-1 recall and Top-1 F1. Furthermore, we implement case studies to further evaluate the accuracy of SPLDHyperAWNTF. As a result, 98 (MDAv2.0) and 98 (MDAv2.0-2) of top-100 are confirmed by HMDDv3.2 dataset. Moreover, the results of enrichment analysis illustrate that unconfirmed potential associations have biological significance.

The effect of the menstrual cycle on the circulating microRNA pool in human plasma: a pilot study

STUDY QUESTION

Do ovarian hormone changes influence the levels of cell-free or circulating microRNA (cf-miRNA) across the menstrual cycle?

SUMMARY ANSWER

This exploratory study suggests that fluctuations in hormonal levels throughout the menstrual cycle may alter cf-miRNAs levels.

WHAT IS KNOWN ALREADY

cf-miRNA levels vary with numerous pathological and physiological conditions in both males and females and are regulated by exogenous and endogenous factors, including hormones.

STUDY DESIGN, SIZE, DURATION

A prospective, monocentric study was conducted between March and November 2021. Since this was a pilot study, the sample size was based on feasibility as well as previous similar human studies conducted in different tissues. A total of 20 participants were recruited for the study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We conducted an exploratory study where blood samples were collected from 16 eumenorrheic females in the early follicular phase, the ovulation phase and the mid-luteal phase of the menstrual cycle. The levels of oestrogen, progesterone, LH and FSH were measured in serum by electrochemiluminescence. The levels of 174 plasma-enriched miRNAs were profiled using a PCR-based panel, including stringent internal and external controls to account for the potential differences in RNA extraction and reverse-transcription stemming from low-RNA input samples.

MAIN RESULTS AND THE ROLE OF CHANCE

This exploratory study suggests that cf-miRNAs may play an active role in the regulation of the female cycle by mediating the expression of genes during fluctuating hormonal changes. Linear mixed-models, adjusted for the relevant variables, showed associations between phases of the menstrual cycle, ovarian hormones and plasma cf-miRNA levels. Validated gene targets of the cf-miRNAs varying with the menstrual cycle were enriched within female reproductive tissues and are primarily involved in cell proliferation and apoptosis.

LARGE SCALE DATA

All relevant data are available from the Mendeley database: LEGER, Bertrand (2022), 'MiRNA and menstrual cycle', Mendeley Data, V1, doi: 10.17632/2br3zp79m3.1.

LIMITATIONS, REASONS FOR CAUTION

Our study was conducted on a small participant cohort. However, it was tightly controlled for endogenous and exogenous confounders, which is critical to ensure robust and reproducible cf-miRNA research. Both adjusted and non-adjusted P-values are presented throughout the article.

WIDER IMPLICATIONS OF THE FINDINGS

Measures of ovarian hormones should be rigorously included in future studies assessing cf-miRNA levels in females and used as time-varying confounders. Our results reinforce the importance of accounting for female-specific biological processes in physiology research by implementing practical or statistical mitigation strategies during data collection and analysis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Clinique romande de réadaptation, Sion, Switzerland. S.L. was supported by an Australian Research Council (ARC) Future Fellowship (FT10100278). D.H. was supported by an Executive Dean's Postdoctoral Research Fellowship from Deakin University. The authors declare no competing interests.

The Role of miR-155 in Antitumor Immunity

MicroRNAs belong to a group of short non-coding RNA molecules that are involved in the regulation of gene expression at multiple levels. Their function was described two decades ago, and, since then, microRNAs have become a rapidly developing field of research. Their participation in the regulation of cellular processes, such as proliferation, apoptosis, cell growth, and migration, made microRNAs attractive for cancer research. Moreover, as a single microRNA can simultaneously target multiple molecules, microRNAs offer a unique advantage in regulating multiple cellular processes in different cell types. Many of these cell types are tumor cells and the cells of the immune system. One of the most studied microRNAs in the context of cancer and the immune system is miR-155. MiR-155 plays a role in modulating innate and adaptive immune mechanisms in distinct immune cell types. As such, miR-155 can be part of the communication between the tumor and immune cells and thus impact the process of tumor immunoediting. Several studies have already revealed its effect on antitumor immune responses, and the targeting of this molecule is increasingly implemented in cancer immunotherapy. In this review, we discuss the current knowledge of miR-155 in the regulation of antitumor immunity and the shaping of the tumor microenvironment, and the plausible implementation of miR-155 targeting in cancer therapy.

High miR-99b expression is associated with cell proliferation and worse patient outcomes in breast cancer

Although miR-99b is a known suppressive microRNA (miRNA) in several cancers, its role in breast cancer has not been elucidated. In this study, we examined the clinical relevance of miR-99b expression in breast cancer. We analyzed miRNA and mRNA expression and their relationships with clinical parameters in 1,961 breast cancer samples from two independent large cohorts, the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA). Several algorithms, including gene set enrichment analysis (GSEA) and xCell, have been used to investigate biological functions and the tumor microenvironment. High miR-99b expression significantly enriched the mTORC1 signaling gene set in breast cancer (NES = 1.63, FDR = 0.03, and NES = 1.58, FDR = 0.10, in METABRIC and TCGA, respectively). No other mechanisms, including the epithelial mesenchymal transition, NFκB, and TGF-β signaling, were consistently enriched in both cohorts. MiR-99b-high breast cancer was associated with high homologous recombination deficiencies, intratumor heterogeneity, and high rates of mutation and neoantigens. In agreement, miR-99b-high breast cancer was associated with increased cell proliferation, correlating with Nottingham histological grade, and significant enrichment of E2F targets, G2/M checkpoint, and mitotic spindle gene sets consistently in both cohorts (P = 0.01, P < 0.001). High miR-99b levels were also associated with low stromal cell fractions in the tumor microenvironment, including adipocytes, keratinocytes, and lymphatic endothelial cells (P < 0.001). However, in both cohorts, miR-99b expression was not associated with significant infiltration of immune cells, except dendritic cells (P = 0.006, 0.020). Finally, in both cohorts, breast cancer with high miR-99b expression was significantly associated with worse disease-free survival (DSS) and overall survival (OS), particularly in estrogen receptor (ER)-positive/human epidermal growth factor (HER)2-negative breast cancer (DSS hazard ratio (HR) 1.29, 95% confidence interval (CI) 1.10-1.51, P < 0.001 in the METABRIC cohort and HR 1.82, 95% CI 1.12-2.98, P = 0.017 in the TCGA cohort). In conclusion, breast cancer with high miR-99b expression was significantly associated with mTORC1 signaling, cell proliferation, and decreased patient survival, particularly in the ER-positive/HER2-negative subtype.

Mesenchymal stem cell-derived exosomes as new tools for delivery of miRNAs in the treatment of cancer

Although ongoing medical research is working to find a cure for a variety of cancers, it continues to be one of the major causes of death worldwide. Chemotherapy and immunotherapy, as well as surgical intervention and radiation therapy, are critical components of cancer treatment. Most anti-cancer drugs are given systemically and distribute not just to tumor tissues but also to normal tissues, where they may cause side effects. Furthermore, because anti-cancer drugs have a low delivery efficiency, some tumors do not respond to them. As a result, tumor-targeted drug delivery is critical for improving the safety and efficacy of anti-cancer treatment. Exosomes are microscopic extracellular vesicles that cells produce to communicate with one another. MicroRNA (miRNA), long non-coding RNA (lncRNA), small interfering RNA (siRNA), DNA, protein, and lipids are among the therapeutic cargos found in exosomes. Recently, several studies have focused on miRNAs as a potential therapeutic element for the treatment of cancer. Mesenchymal stem cells (MSC) have been known to have angiogenic, anti-apoptotic, anti-inflammatory and immunomodulatory effects. Exosomes derived from MSCs are gaining popularity as a non-cellular alternative to MSC-based therapy, as this method avoids unwanted lineage differentiation. Therefore more research have focused on transferring miRNAs to mesenchymal stem cells (MSC) and targeting miRNA-loaded exosomes to cancer cells. Here, we initially gave an overview of the characteristics and potentials of MSC as well as the use of MSC-derived exosomes in cancer therapy. Finally, we emphasized the utilization of MSC-derived exosomes for miRNA delivery in the treatment of cancer.

Sensitive colorimetric detection of miRNA-155 via G-quadruplex DNAzyme decorated spherical nucleic acid

Rapid and sensitive detection of biomarkers enables monitoring patients' health status and can enhance the early diagnosis of deadly diseases. In this work, we have developed a new colorimetric platform based on spherical nucleic acid (SNA) and G-quadruplex DNAzymes for the identification of specific miRNAs. The simple hybridization between the target miRNA and two capture probes (capture probe 1 located at AuNP surface and free capture probe 2) is the working principle of this biosensor. The hybridization and duplex formation among probes and miRNAs led to a significant decrease in the intensity of color change. A linear relationship between the decrease of colorimetric signal and the amount of target molecules was witnessed from 1 to 100 nM for miRNA-155. Using this method, we were able to detect concentrations of miRNA-155 as low as 0.7 nM. Furthermore, the proposed sensing platform can be utilized profitably to detect miRNA-155 in real human serum samples. We further investigated the applicability of the proposed method in a microfluidic system which displayed promising results. In this project, A G-quadruplex based SNAzyme was constructed to provide a fast and simple colorimetric method for miRNA detection. The SNAzyme actually employed as both target recognition element and catalytic nano labels for colorimetric detection.

An ultrasensitive hairpin sensor based on g-C3N4 nanocomposite for the detection of miRNA-155 in breast cancer patient serum

Achieving the early diagnosis of breast cancer, through ultrasensitive detection of tumor marker miRNA-155, is a significant challenge. Therefore, an ultrasensitive hairpin electrochemical biosensor based on graphite-like phase carbon nitride composite was proposed. In this paper, poly(D-glucosamine) (PDG) was used as a stabilizer and reducing agent to prepare gold nanoparticles at room temperature, and then a graphite-like phase with a two-dimensional lamellar structure carbon nitride was further combined with it to obtain the poly(D-glucosamine)/gold nanoparticles/graphite-like phase carbon nitride nanocomposite (PDG/AuNPs/g-C₃N₄), in order to achieve the goal of signal amplification. The specific hairpin capture probe (HP) that recognized and bound miRNA-155 was then grafted. The hairpin biosensor showed a linear range of 0.1 fM-1 pM with a detection limit of 0.05 fM using differential pulse voltammetry (DPV) electrochemical analysis. Furthermore, the excellent performance hairpin electrochemical biosensor had been applied to the detection of miRNA-155 in human serum samples with good recovery.

Potential utility of miRNAs for liquid biopsy in breast cancer

Breast cancer (BC) remains the most prevalent malignancy due to its incidence rate, recurrence, and metastasis in women. Conventional strategies of cancer detection– mammography and tissue biopsy lack the capacity to detect the complete cancer genomic landscape. Besides, they often give false- positive or negative results. The presence of this and other disadvantages such as invasiveness, high-cost, and side effects necessitates developing new strategies to overcome the BC burden. Liquid biopsy (LB) has been brought to the fore owing to its early detection, screening, prognosis, simplicity of the technique, and efficient monitoring. Remarkably, microRNAs (miRNAs)– gene expression regulators seem to play a major role as biomarkers detected in the samples of LB. Particularly, miR-21 and miR-155 among other possible candidates seem to serve as favorable biomarkers in the diagnosis and prognosis of BC. Hence, this review will assess the potential utility of miRNAs as biomarkers and will highlight certain promising candidates for the LB approach in the diagnosis and management of BC that may optimize the patient outcome.

Hypoxia-responsive circRNAs: A novel but important participant in non-coding RNAs ushered toward tumor hypoxia

Given the rapid developments in RNA-seq technologies and bioinformatic analyses, circular RNAs (circRNAs) have gradually become recognized as a novel class of endogenous RNAs, characterized by covalent loop structures lacking free terminals, which perform multiple biological functions in cancer genesis, progression and metastasis. Hypoxia, a common feature of the tumor microenvironments, profoundly affects several fundamental adaptive responses of tumor cells by regulating the coding and non-coding transcriptomes and renders cancer's phenotypes more aggressive. Recently, hypoxia-responsive circRNAs have been recognized as a novel player in hypoxia-induced non-coding RNA transcriptomics to modulate the hypoxic responses and promote the progression and metastasis of hypoxic tumors. Moreover, via extracellular vesicles-exosomes, these hypoxia-responsive circRNAs could transmit hypoxia responses from cancer cells to the cells of surrounding matrices, even more distant cells of other organs. Here, we have summarized what is known about hypoxia-responsive circRNAs, with a focus on their interaction with hypoxia-inducible factors (HIFs), regulation of hypoxic responses and relevance with malignant carcinoma's clinical features, which will offer novel insights on the non-coding RNAs' regulation of cancer cells under hypoxic stress and might aid the identification of new theranostic targets and define new therapeutic strategies for those cancer patients with resistance to radiochemotherapy, because of the ubiquity of tumoral hypoxia.

Oncogenic Role of miR-217 During Clear Cell Renal Carcinoma Progression

Clear cell renal carcinoma (ccRC) comprises a set of heterogeneous, fast-progressing pathologies with poor prognosis. Analyzing ccRC progression in terms of modifications at the molecular level may provide us with a broader understanding of the disease, paving the way for improved diagnostics and therapeutics. The role of micro-RNAs (miRs) in cancer by targeting both oncogenes and tumor suppressor genes is widely known. Despite this knowledge, the role of specific miRs and their targets in the progression of ccRC is still unknown. To evaluate the action of miRs and their target genes during ccRC progression, here we implemented a three-step method for constructing miR–gene co-expression networks for each progression stage of ccRC as well as for adjacent-normal renal tissue (NT). In the first step, we inferred all miR–gene co-expression interactions for each progression stage of ccRC and for NT. Afterwards, we filtered the whole miR–gene networks by differential gene and miR expression between successive stages: stage I with non-tumor, stage II with stage I, and so on. Finally, all miR–gene interactions whose relationships were inversely proportional (overexpressed miR and underexpressed genes and vice versa) were kept and removed otherwise. We found that miR-217 is differentially expressed in all contrasts; however, its targets were different depending on the ccRC stage. Furthermore, the target genes of miR-217 have a known role in cancer progression—for instance, in stage II network, GALNTL6 is overexpressed, and it is related to cell signaling, survival, and proliferation. In the stage III network, WNK2, a widely known tumor suppressor, is underexpressed. For the stage IV network, IGF2BP2, a post-transcriptional regulator of MYC and PTEN, is overexpressed. This data-driven network approach has allowed us to discover miRs that have different targets through ccRC progression, thus providing a method for searching possible stage-dependent therapeutic targets in this and other types of cancer.

Resveratrol Downregulates miR-155-5p to Block the Malignant Behavior of Gastric Cancer Cells

Studies have shown that resveratrol (Res) exerts significant antiproliferative effects in cancer, and regulating the expression of microRNAs (miRNAs) is one the underlying mechanisms of these effects. Overexpression of miR-155-5p leads to oncogenesis. However, it is unclear whether Res exerts antitumor effects by regulating the expression of miR-155-5p, and its specific mechanism in gastric cancer remains unknown. In this study, qRT-PCR was performed to assess the expression of miR-155-5p in gastric cells and clinical tissues, and the MTT assay, plate clone formation test, cell scratch test, Transwell assay, and flow cytometry were performed to investigate the functions of Res on the growth of gastric cancer cells after treatment with miR-155-5p. Western blot analysis was performed to detect the expression of claudin 1, c-Myc, cyclin D1, Bcl-2, and caspase-3 proteins in gastric cancer cell lines after treatment with miR-155-5p and Res. We found that miR-155-5p was overexpressed in gastric cancer cells and clinical tissues, while Res inhibited gastric cancer cell growth by regulating miR-155-5p expression. The results of MTT assay, plate clone formation test, cell scratch test, Transwell test, and flow cytometry showed that miR-155-5p promoted the proliferation, invasion, and metastasis of gastric cancer cell lines and inhibited apoptosis, while Res addition inhibited this effect ( $P<0.05$ ). When miR-155-5p was overexpressed, the expressions of claudin 1, c-Myc, cyclin D1, and Bcl-2 were upregulated and that of caspase-3 was downregulated. Collectively, these results suggest that miR-155-5p may be a therapeutic target in gastric cancer, and Res may be a potential therapeutic agent based on its regulation of miR-155-5p.

MicroRNA-184 attenuates hypoxia and oxidative stress-related injury via suppressing apoptosis, DNA damage and angiogenesis in an in vitro age-related macular degeneration model

Age-related macular degeneration (AMD) is one of the leading causes of blindness worldwide, particularly in developed countries. Recently, microRNAs (miRs) have become popular research area to develop new treatment options of AMD. However, interaction between hsa-miR-184 and AMD remain largely unexplored. In this study, sub-lethal levels of Deforoxamine Mesylate salt (DFX) and H₂O₂ were applied to ARPE-19 cells to establish a severe in vitro AMD model, via durable hypoxia and oxidative stress. We found that up-regulation of miR-184 level in AMD can suppress hypoxia-related angiogenic signals through HIF-1α/VEGF/MMPs axis. Also, miR-184 suppressed the hypoxia sensor miR-155 and genes in the EGFR/PI3K/AKT pathway, which is an alternative pathway in angiogenesis. To investigate the mechanism behind this protective effect, we evaluated the impact of miR-184 on retinal apoptosis in a model of AMD. miR-184 inhibited retinal apoptosis by upregulating BCL-2 and downregulating pro-apoptototic BAX, TRAIL, Caspase 3 and 8 signals as well as p53. Taken together, miR-184 attenuates retinal cell damage induced by severe AMD pathologies through suppressing hypoxia, angiogenesis and apoptosis. The safety profile of miR-184 was observed to be similar to Bevacizumab, which is in wide use clinically, but miR-184 was found to provide a more effective therapeutic potential by regulating simultaneously multiple pathologies.