Profiling of microRNAs in tumor interstitial fluid of breast tumors - a novel resource to identify biomarkers for prognostic classification and detection of cancer

MicroRNA-206 suppresses growth and metastasis of breast cancer stem cells via blocking EVI-1-mediated CALR expression

Aim to investigate the effect of miR-206 on the growth and metastasis of breast cancer stem cells and clarify the precise mechanism of miR-206 on EVI-1-mediated CALR expression in driving malignant phenotype. Our results showed that miR-206 mimics suppressed CALR expression, inhibited the proliferation and metastasis ability of breast cancer stem cells and finally induced cellular apoptosis. Over-expression of CALR could effectively attenuate the cytotoxic effect of miR-206. Further studies demonstrated that EVI-1 could be served as a key regulator of miR206-mediated CALR expression. Elevation of EVI-1 can reverse the function of miR-206 on induction of CALR.

MiRNA expression deregulation correlates with the Oncotype DX® DCIS score

Background

Current clinical criteria do not discriminate well between women who will or those who will not develop ipsilateral invasive breast cancer (IBC), or a DCIS recurrence after a ductal carcinoma in situ (DCIS) diagnosis. The 12-gene Oncotype DX® DCIS assay (RT qPCR gene-based scoring system) was established and shown to predict the risk of subsequent ipsilateral IBC or DCIS recurrence. Recent studies have shown that microRNA (miRNA) expression deregulation can contribute to the development of IBC, but very few have evaluated miRNA deregulation in DCIS lesions. In this study, we sought to determine whether specific miRNA expression changes may correlate with Oncotype DX® DCIS scores.

Methods

For this study, we used archived formalin-fixed, paraffin-embedded (FFPE) specimens from 41 women diagnosed with DCIS between 2012 and 2018. The DCIS lesions were stratified into low (n = 26), intermediate (n = 10), and high (n = 5) risk score groups using the Oncotype DX® DCIS assay. Total RNA was extracted from DCIS lesions by macro-dissection of unstained FFPE sections, and next-generation small-RNA sequencing was performed. We evaluated the correlation between miRNA expression data and Oncotype score, as well as patient age. RT-qPCR validations were performed to validate the topmost differentially expressed miRNAs identified between the different risk score groups.

Results

MiRNA sequencing of 32 FFPE DCIS specimens from the three different risk group scores identified a correlation between expression deregulation of 17 miRNAs and Oncotype scores. Our analyses also revealed a correlation between the expression deregulation of 9 miRNAs and the patient’s age. Based on these results, a total of 15 miRNAs were selected for RT-qPCR validation. Of these, miR-190b (p = 0.043), miR-135a (p = 0.05), miR-205 (p = 0.00056), miR-30c (p = 0.011), and miR-744 (p = 0.038) showed a decreased expression in the intermediate/high Oncotype group when compared to the low-risk score group. A composite risk score was established using these 5 miRNAs and indicated a significant association between miRNA expression deregulation and the Oncotype DX® DCIS Score (p < 0.0021), between high/intermediate and low risk groups.

Conclusions

Our analyses identified a subset of 5 miRNAs able to discriminate between Oncotype DX® DCIS score subgroups. Together, our data suggest that miRNA expression analysis may add value to the predictive and prognostic evaluation of DCIS lesions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01558-4.

End-to-end design of wearable sensors

Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.

Quantitative and Multiplex Detection of Extracellular Vesicle-Derived MicroRNA via Rolling Circle Amplification within Encoded Hydrogel Microparticles

Extracellular vesicle-derived microRNA (EV-miRNA) represent a promising cancer biomarker for disease diagnosis and monitoring. However, existing techniques to detect EV-miRNA rely on complex, bias-prone strategies, and preprocessing steps, making absolute quantification highly challenging. This work demonstrates the development and application of a method for quantitative and multiplex detection of EV-miRNA, via rolling circle amplification within encoded hydrogel particles. By a one-pot extracellular vesicle lysis and microRNA capture step, the bias and losses associated with standard RNA extraction techniques is avoided. The system offers a large dynamic range (3 orders of magnitude), ease of multiplexing, and a limit of detection down to 2.3 zmol (46 × 10-18 m), demonstrating its utility in clinical applications based on liquid biopsy tests. Furthermore, orthogonal measurements of EV concentrations coupled with the direct, absolute quantification of miRNA in biological samples results in quantitative measurements of miRNA copy numbers per volume sample, and per extracellular vesicle.

Microneedle-Based Device for Biological Analysis

The collection and analysis of biological samples are an effective means of disease diagnosis and treatment. Blood sampling is a traditional approach in biological analysis. However, the blood sampling approach inevitably relies on invasive techniques and is usually performed by a professional. The microneedle (MN)-based devices have gained increasing attention due to their noninvasive manner compared to the traditional blood-based analysis method. In the present review, we introduce the materials for fabrication of MNs. We categorize MN-based devices based on four classes: MNs for transdermal sampling, biomarker capture, detecting or monitoring analytes, and bio-signal recording. Their design strategies and corresponding application are highlighted and discussed in detail. Finally, future perspectives of MN-based devices are discussed.

Are miRNAs Dynamic Biomarkers in Keratoconus? A Review of the Literature

Aim: A review of miRNA (microRNA) profiling studies in keratoconus. Methods: Literature search strategy—PubMed central database, using miRNA or microRNA and keratoconus as keywords. Results: Eleven experimental or clinical studies on humans regarding miRNA and keratoconus, published in English between 2009 and 2020 were retrieved. Conclusion: The publications regarding the role of miRNAs in keratoconus are scarce and diverse but provide some valuable information about potential new mechanisms of keratoconus development and progression. The cornea expresses almost 300 different miRNAs, 18 of which are specific, and miR-184 is by far the most abundant, with expression restricted to central basal and suprabasal epithelial cells. Mutations in the seed region of MIR184 were proved to be rare and nonspecific in patients with isolated keratoconus. Overall, in keratoconus, a total of 29 miRNAs were upregulated, and 11 were downregulated. It appeared that miR-143-3p, miR-182-5p, and miR-92a-3p were highly expressed, while the miRNAs connected to cell–cell junction, cell division, and motor activity were downregulated. In less advanced forms, altered expression of four miRNAs—miR-151a-3p, miR-194-5p, miR-195-5p, miR-185-5p—was proved in the cone epithelium; in contrast, in advanced keratoconus, the expression of miR-151a-3p and miR-194-5p remained altered, changes in the expression of miR-195 and miR-185 were not reported, and the expression of miR-138-5p, miR-146b-5p, miR-28-5p, and miR-181a-2-3p was also altered in the corneal epithelium. Keratoconus is a dynamic process of corneal stromal thinning that might result from a dynamic miRNA expression in the corneal epithelium exposed to environmental and behavioral factors causing repetitive traumas. Further experimental studies are needed to prove this hypothesis.

Beyond liquid biopsy: Toward non-invasive assays for distanced cancer diagnostics in pandemics

Liquid biopsy technologies have seen a significant improvement in the last decade, offering the possibility of reliable analysis and diagnosis from several biological fluids. The use of these technologies can overcome the limits of standard clinical methods, related to invasiveness and poor patient compliance. Along with this there are now mature examples of lab-on-chips (LOC) which are available and could be an emerging and breakthrough technology for the present and near-future clinical demands that provide sample treatment, reagent addition and analysis in a sample-in/answer-out approach. The possibility of combining non-invasive liquid biopsy and LOC technologies could greatly assist in the current need for minimizing exposure and transmission risks. The recent and ongoing pandemic outbreak of SARS-CoV-2, indeed, has heavily influenced all aspects of life worldwide. Ordinary tasks have been forced to switch from “in presence” to “distanced”, limiting the possibilities for a large number of activities in all fields of life outside of the home. Unfortunately, one of the settings in which physical distancing has assumed noteworthy consequences is the screening, diagnosis and follow-up of diseases.

In this review, we analyse biological fluids that are easily collected without the intervention of specialized personnel and the possibility that they may be used -or not-for innovative diagnostic assays. We consider their advantages and limitations, mainly due to stability and storage and their integration into Point-of-Care diagnostics, demonstrating that technologies in some cases are mature enough to meet current clinical needs.

Diagnosis, biology and epidemiology of oligometastatic breast cancer

Does oligometastatic breast cancer (OMBC) deserve a dedicated treatment? Although some authors recommend multidisciplinary management of OMBC with a curative intent, there is no evidence proving this strategy beneficial in the absence of a randomized trial. The existing literature sheds little light on OMBC. Incidence is unknown; data available are either obsolete or biased; there is no consensus on the definition of OMBC and metastatic sites, nor on necessary imaging techniques. However, certain proposals merit consideration. Knowledge of eventual specific OMBC biological characteristics is limited to circulating tumor cell (CTC) counts. Given the data available for other cancers, studies on microRNAs (miRNAs), circulating tumor DNA (ctDNA) and genomic alterations should be developed Finally, safe and effective therapies do exist, but results of randomized trials will not be available for many years. Prospective observational cohort studies need to be implemented.

Construction of Potential Gene Expression and Regulation Networks in Prostate Cancer Using Bioinformatics Tools

Objective

To identify the key genes involved in prostate cancer and their regulatory network.

Methods

The dataset of mRNA/miRNA transcriptome sequencing was downloaded from The Cancer Genome Atlas/the Gene Expression Omnibus database for analysis. The “edgeR” package in the R environment was used to normalize and analyze differentially expressed genes (DEGs) and miRNAs (DEmiRNAs). First, the PANTHER online tool was used to analyze the function enrichment of DEGs. Next, a protein-protein interaction (PPI) network was constructed using STRING and Cytoscape tools. Finally, miRNA-gene regulatory networks were constructed using the miRTarBase.

Results

We identified 4339 important DEGs, of which 2145 were upregulated (Up-DEGs) and 2194 were downregulated (Down-DEGs). Functional enrichment analysis showed that the Up-DEGs were related to the immune system and the cell cycle in prostate cancer, whereas the Down-DEGs were related to the nucleic acid metabolic process and metabolism pathways. Twelve core protein clusters were found in the PPI network. Further, the constructed miRNA-gene interaction network showed that 11 downregulated miRNAs regulated 16 Up-DEGs and 22 upregulated miRNAs regulated 22 Down-DEGs.

Conclusion

We identified 4339 genes and 70 miRNAs that may be involved in immune response, cell cycle, and other key pathways of the prostate cancer regulatory network. Genes such as BUB1B, ANX1A1, F5, HTR4, and MUC4 can be used as biomarkers to assist in the diagnosis and prognosis of prostate cancer.

Microneedle Arrays for Sampling and Sensing Skin Interstitial Fluid

Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs, and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection are discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and sampling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays is discussed. Finally, future directions to develop a point-of-care (POC) device to sample ISF are proposed.

Identification of miR‑25‑3p as a tumor biomarker: Regulation of cellular functions via TOB1 in breast cancer

Breast cancer is the most common cancer in women and is one of the three most common malignancies worldwide. Serum microRNAs (miRNAs/miRs) are ideal biomarkers for tumor diagnosis and prognosis due to their specific biological characteristics. In several different types of cancer, miRNAs are associated with cell migration and invasion. In the present study, miR‑25‑3p expression levels were detected in tissue and serum samples derived from patients with breast cancer, and the diagnostic and prognostic value of miR‑25‑3p in breast cancer was evaluated. Cellular function assays were performed to evaluate the role of miR‑25‑3p in breast cancer. Moreover, dual‑luciferase reporter assays and western blotting were performed to investigate the target of miR‑25‑3p. miR‑25‑3p expression was upregulated in breast cancer tissue and serum samples compared with normal breast tissue and serum samples. Patients with breast cancer with high serum miR‑25‑3p levels were more likely to have lymph node metastasis compared with those with low serum miR‑25‑3p levels. The area under the curve for miR‑25‑3p in the diagnosis of breast cancer was 0.748, with 57.1% sensitivity and 95.0% specificity. Moreover, the Kaplan‑Meier survival curves demonstrated that patients with breast cancer with a low expression of serum miR‑25‑3p had a higher overall survival rate compared with patients with a high serum miR‑25‑3p expression. miR‑25‑3p knockdown suppressed breast cancer cell proliferation and invasion, and transducer of ERBB2, 1 (TOB1) was identified as a potential target gene regulated by miR‑25‑3p. Therefore, the present study suggested that miR‑25‑3p regulated cellular functions via TOB1 in breast cancer; therefore, miR‑25‑3p may serve as a breast cancer biomarker.

Exosomal miR-500a-5p derived from cancer-associated fibroblasts promotes breast cancer cell proliferation and metastasis through targeting USP28

The tumor microenvironment contributes to tumor progression and metastasis. Cancer-associated fibroblasts (CAFs) form a major cellular component of the tumor microenvironment. In this study, we further explored the mechanisms underlying the tumor-promoting roles of CAFs.

Methods: Patient-derived CAFs and normal fibroblasts (NFs) were isolated from breast carcinomas and adjacent normal breast tissue. Exosomes were isolated by ultracentrifugation and CAF-derived exosomal microRNAs were screened using next-generation sequencing technology. MiR-500a-5p expression was assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization; Tumor cell proliferation was determined by MTT assays and three-dimensioned (3D) cultures, and tumor metastasis was determined by Transwell assays in vitro. In vivo assays were performed in a nude mouse subcutaneous xenograft model.

Results: We confirmed that CAF-derived exosomes significantly promoted the proliferation and metastasis of breast cancer cells. MiR-500a-5p was highly expressed in MDA-MB-231 and MCF7 cells treated with CAF-derived exosomes. The upregulation of miR-500a-5p was also confirmed in CAFs and CAF-derived exosomes. MiR-500a-5p was transferred from CAFs to the cancer cells, and subsequently promoted proliferation and metastasis by binding to ubiquitin-specific peptidase 28 (USP28).

Conclusions: The present study demonstrates that CAFs promote breast cancer progression and metastasis via exosomal miR-500a-5p and indicate that inhibiting CAF-derived miR-500a-5p is an alternative modality for the treatment of breast cancer.

High-Resolution Patterning of Hydrogel Sensing Motifs within Fibrous Substrates for Sensitive and Multiplexed Detection of Biomarkers

There has been an increasing and urgent demand to develop nucleic acid bioassays which not only offer high analytical performance but which are also amenable with point-of-care testing. Hydrogels present a versatile class of materials with biocompatible antifouling properties and the ability to be engineered for a range of advanced sensing applications. Fibrous substrates like nitrocellulose offer low-cost and durable platforms to run complex bioassays while enabling portability and ease of handling. We demonstrate herein the ability to synergistically combine these two materials into a portable biosensing platform by leveraging projection lithography. We demonstrate the direct polymerization of hydrogel sensing motifs within a range of fibrous substrates with precise control over their shape, size, location, and functionality. Spatial encoding of the hydrogel motifs enables the multiplex detection of multiple biomarkers on the same test. As a proof-of-concept, we apply the platform to the detection of microRNA, an emerging class of circulating biomarkers with promising potential for early diagnosis and monitoring of cancer. The assay offers a large dynamic range (over three orders of magnitude), high sensitivity (limit of detection of 2.5 amol), as well as versatility and ease of handling. Finally, the bioassay is validated using real biological samples, namely, total RNA extracted from the sera of late-stage breast cancer patients, demonstrating its utility and compatibility with clinical biosensing applications.

High-throughput proteomics of breast cancer interstitial fluid: identification of tumor subtype-specific serologically relevant biomarkers

Despite significant advancements in breast cancer (BC) research, clinicians lack robust serological protein markers for accurate diagnostics and tumor stratification. Tumor interstitial fluid (TIF) accumulates aberrantly externalized proteins within the local tumor space, which can potentially gain access to the circulatory system. As such, TIF may represent a valuable starting point for identifying relevant tumor-specific serological biomarkers. The aim of the study was to perform comprehensive proteomic profiling of TIF to identify proteins associated with BC tumor status and subtype. A liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of 35 TIFs of three main subtypes: luminal (19), Her2 (4), and triple-negative (TNBC) (12) resulted in the identification of > 8800 proteins. Unsupervised hierarchical clustering segregated the TIF proteome into two major clusters, luminal and TNBC/Her2 subgroups. High-grade tumors enriched with tumor infiltrating lymphocytes (TILs) were also stratified from low-grade tumors. A consensus analysis approach, including differential abundance analysis, selection operator regression, and random forest returned a minimal set of 24 proteins associated with BC subtypes, receptor status, and TIL scoring. Among them, a panel of 10 proteins, AGR3, BCAM, CELSR1, MIEN1, NAT1, PIP4K2B, SEC23B, THTPA, TMEM51, and ULBP2, was found to stratify the tumor subtype-specific TIFs. In particular, upregulation of BCAM and CELSR1 differentiates luminal subtypes, while upregulation of MIEN1 differentiates Her2 subtypes. Immunohistochemistry analysis showed a direct correlation between protein abundance in TIFs and intratumor expression levels for all 10 proteins. Sensitivity and specificity were estimated for this protein panel by using an independent, comprehensive breast tumor proteome dataset. The results of this analysis strongly support our data, with eight of the proteins potentially representing biomarkers for stratification of BC subtypes. Five of the most representative proteomics databases currently available were also used to estimate the potential for these selected proteins to serve as putative serological markers.

MiR-19b-3p accelerates bone loss after spinal cord injury by suppressing osteogenesis via regulating PTEN/Akt/mTOR signalling

Rapid and extensive bone loss, one of the skeletal complications after spinal cord injury (SCI) occurrence, drastically sacrifices the life quality of SCI patients. It has been demonstrated that microRNA (miRNA) dysfunction plays an important role in the initiation and development of bone loss post-SCI. Nevertheless, the effect of miR-19b-3p on bone loss after SCI is unknown and the accurate mechanism is left to be elucidated. The present work was conducted to explore the role of miR-19b-3p/phosphatase and tensin homolog deleted on chromosome ten (PTEN) axis on osteogenesis after SCI and further investigates the underlying mechanisms. We found that miR-19b-3p level was increased in the femurs of SCI rats with decreased autophagy. The overexpression of miR-19b-3p in bone marrow mesenchymal stem cells (BMSCs) targeted down-regulation of PTEN expression, facilitated protein kinase B (Akt) and mammalian target of rapamycin (mTOR) phosphorylation, and thereby suppressing BMSCs osteogenic differentiation via autophagy. Besides, the inhibiting effects of miR-19b-3p on osteogenic differentiation of BMSCs could be diminished by autophagy inducer rapamycin. Meanwhile, bone loss after SCI in rats was also reversed by antagomir-19b-3p treatment, suggesting miR-19b-3p was an essential target for osteogenic differentiation via regulating autophagy. These results indicated that miR-19b-3p was involved in bone loss after SCI by inhibiting osteogenesis via PTEN/Akt/mTOR signalling pathway.

Upregulated N6-Methyladenosine RNA in Peripheral Blood: Potential Diagnostic Biomarker for Breast Cancer

Purpose

An effective biomarker for the diagnosis of breast cancer (BC) and benign breast diseases (BBD) is crucial for improving the prognosis. We investigated whether N6-methyladenosine (m⁶A) can be a diagnostic biomarker of BC.

Materials and Methods

We detected the contents of peripheral blood m⁶A in 62 patients with BC, 41 patients with BBD, and 41 normal controls (NCs) using the colorimetric method. The relative expression of the m⁶A regulated genes methyltransferase-like 14 (METTL14) and fat mass and obesity-associated (FTO) was analyzed using quantitative real-time polymerase chain reaction.

Results

m⁶A in peripheral blood RNA was significantly higher in patients with BC than that in patients with BBD (p < 0.001) or the NCs (p < 0.001). m⁶A was closely associated with the disease stage (from stage 0 to stage I-IV, p=0.003). The receiver operating characteristic curve of m⁶A contained an area under the curve (AUC) value of 0.887 in BC, which was greater than that of carcinoembryonic antigen (CEA) or carbohydrate antigen 153 (CA153). The combination of m⁶A, CEA, and CA153 improved the AUC to 0.914. The upregulated and downregulated mRNA expression of METTL14 and FTO, respectively, might contribute to the increase of m⁶A in patients with BC. m⁶A combined with METTL14 and FTO improved the AUC to 0.929 with a specificity of 97.4% in the peripheral blood of patients with BC.

Conclusion

The peripheral blood RNA of m⁶A might be a valuable biomarker for the diagnosis of BC.

Cancer-associated adipocytes: emerging supporters in breast cancer

Breast cancer (BC) is a malignant breast tumor confronted with high invasion, metastasis and recurrence rate, and adipocytes are the largest components in breast tissue. The aberrant adipocytes, especially the BC-neighbored cancer-associated adipocytes (CAAs), are found in the invasive front of BC. CAAs present a vicious phenotype compared with mature mammary adipocytes and mediate the crosstalk network between adipocytes and BC cells. By releasing multiple adipokines such as leptin, adiponectin, interleukin (IL)-6, chemokine ligand 2 (CCL2) and chemokine ligand 5 (CCL5), CAAs play essential roles in favor of proliferation, angiogenesis, dissemination, invasion and metastasis of BC. This article reviews the recent existing CAAs studies on the functions and mechanisms of adipocytes in the development of BC, including adipokine regulating, metabolic reprogramming, extracellular matrix (ECM) remodeling, microRNAs (miRNAs) and immune cell adjusting. Besides, adipocyte secretome and cellular interactions are implicated in the intervention to BC therapy and autologous fat grafting of breast reconstruction. Therefore, the potential functions and mechanisms of CAAs are very important for unveiling BC oncogenesis and progress. Deciphering the complex network between CAAs and BC is critical for designing therapeutic strategies and achieving the maximum therapeutic effects of BC.

Downregulation of circ_0132266 in chronic lymphocytic leukemia promoted cell viability through miR-337-3p/PML axis

Circular RNAs (circRNAs) have recently been reported to play crucial roles in various regulatory processes and involved in cancer onset and progression. However, the potential mechanism of circRNAs in chronic lymphocytic leukemia (CLL) remains largely unknown. Here, we observed hsa_circ_0132266 (circ_0132266), a circRNA significantly decreased in the peripheral blood mononuclear cells (PBMCs) of CLL patients compared with healthy donors, could act as an endogenous sponge of hsa-miR-337-3p (miR-337-3p) and regulate its activity, which resulted in a downstream change of target-gene PML and a consequent influence on cell viability. Taken together, our data indicated the regulatory mechanism of circ_0132266 in CLL progression through circ_0132266/miR-337-3p/PML axis, suggesting that it may serve as a biomarker as well as an exploitable therapeutic target for CLL.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

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

Secreted breast tumor interstitial fluid microRNAs and their target genes are associated with triple-negative breast cancer, tumor grade, and immune infiltration

Background

Studies on tumor-secreted microRNAs point to a functional role of these in cellular communication and reprogramming of the tumor microenvironment. Uptake of tumor-secreted microRNAs by neighboring cells may result in the silencing of mRNA targets and, in turn, modulation of the transcriptome. Studying miRNAs externalized from tumors could improve cancer patient diagnosis and disease monitoring and help to pinpoint which miRNA-gene interactions are central for tumor properties such as invasiveness and metastasis.

Methods

Using a bioinformatics approach, we analyzed the profiles of secreted tumor and normal interstitial fluid (IF) microRNAs, from women with breast cancer (BC). We carried out differential abundance analysis (DAA), to obtain miRNAs, which were enriched or depleted in IFs, from patients with different clinical traits. Subsequently, miRNA family enrichment analysis was performed to assess whether any families were over-represented in the specific sets. We identified dysregulated genes in tumor tissues from the same cohort of patients and constructed weighted gene co-expression networks, to extract sets of co-expressed genes and co-abundant miRNAs. Lastly, we integrated miRNAs and mRNAs to obtain interaction networks and supported our findings using prediction tools and cancer gene databases.

Results

Network analysis showed co-expressed genes and miRNA regulators, associated with tumor lymphocyte infiltration. All of the genes were involved in immune system processes, and many had previously been associated with cancer immunity. A subset of these, BTLA, CXCL13, IL7R, LAMP3, and LTB, was linked to the presence of tertiary lymphoid structures and high endothelial venules within tumors. Co-abundant tumor interstitial fluid miRNAs within this network, including miR-146a and miR-494, were annotated as negative regulators of immune-stimulatory responses. One co-expression network encompassed differences between BC subtypes. Genes differentially co-expressed between luminal B and triple-negative breast cancer (TNBC) were connected with sphingolipid metabolism and predicted to be co-regulated by miR-23a. Co-expressed genes and TIF miRNAs associated with tumor grade were BTRC, CHST1, miR-10a/b, miR-107, miR-301a, and miR-454.

Conclusion

Integration of IF miRNAs and mRNAs unveiled networks associated with patient clinicopathological traits, and underlined molecular mechanisms, specific to BC sub-groups. Our results highlight the benefits of an integrative approach to biomarker discovery, placing secreted miRNAs within a biological context.

MiR-18a and miR-18b are expressed in the stroma of oestrogen receptor alpha negative breast cancers

BACKGROUND

Previously, we have shown that miR-18a and miR-18b gene expression strongly correlates with high proliferation, oestrogen receptor -negativity (ER^-), cytokeratin 5/6 positivity and basal-like features of breast cancer.

METHODS

We investigated the expression and localization of miR-18a and -18b in formalin fixed paraffin embedded (FFPE) tissue from lymph node negative breast cancers (n = 40), by chromogenic in situ hybridization (CISH). The expression level and in situ localization of miR-18a and -18b was assessed with respect to the presence of tumour infiltrating lymphocytes (TILs) and immunohistochemical markers for ER, CD4, CD8, CD20, CD68, CD138, PAX5 and actin. Furthermore, in two independent breast cancer cohorts (94 and 377 patients) the correlation between miR-18a and -18b expression and the relative quantification of 22 immune cell types obtained from the CIBERSORT tool was assessed.

RESULTS

CISH demonstrated distinct and specific cytoplasmic staining for both miR-18a and miR-18b, particularly in the intratumoural stroma and the stroma surrounding the tumour margin. Staining by immunohistochemistry revealed some degree of overlap of miR-18a and -18b with CD68 (monocytes/macrophages), CD138 (plasma cells) and the presence of high percentages of TILs. CIBERSORT analysis showed a strong correlation between M1-macrophages and CD4+ memory activated T-cells with mir-18a and -18b.

CONCLUSIONS

Our study demonstrates that miR-18a and miR-18b expression is associated with ER- breast tumours that display a high degree of inflammation. This expression is potentially associated specifically with macrophages. These results suggest that miR-18a and miR-18b may play a role in the systemic immunological response in ER^- tumours.

MicroRNA-342 targets Cofilin 1 to suppress the growth, migration and invasion of human breast cancer cells

MicroRNA-342-3p (miR-342) has been shown to act as a tumor-suppressor in different cancer types. However, the role and therapeutic implications of miR-342 via modulation of Cofilin 1 (CFL1) has not been studied in any type of cancer. Given the importance of Cofilin signalling in breast, this study was undertaken to explore the therapeutic implications of miR-342 and its target CFL1 in breast cancer. Herein, we found that miR-342 was significantly (P < 0.05) downregulated in breast cancer tissues and cell lines. Functional assays revealed that overexpression of miR-342 caused a significant (P < 0.05) inhibition of the proliferation, colony formation, invasion and migration of the MDA-MB-436 and CAMA-1 breast cancer cells via induction of apoptosis. Bioinformatic approaches and the dual luciferase reporter assay confirmed the interaction between miR-342 and its target CFL1. Moreover, we found that CFL1 was aberrantly overexpressed in breast cancer tissues and cell lines. Overexpression of miR-342 caused remarkable depletion in the expression of CFL1 in MDA-MB-436 breast cancer cells. Silencing of CFL1 in CAMA-1 and MDA-MB-436 cells caused remarkable decrease in the proliferation, colony formation and migration of these cells, similar to that of miR-342 ovexpression. However, overexpression of CFL1 in MDA-MB-346 cells could avoid the tumor suppressive effects of miR-342. Our data provide novel information about the implications of miR-342 and its target CFL1 in breast cancer treatment.

miRNAs as radio-response biomarkers for breast cancer stem cells

In breast cancer (BC), the presence of cancer stem cells (CSCs) has been related to relapse, metastasis, and radioresistance. Radiotherapy (RT) is an extended BC treatment, but is not always effective. CSCs have several mechanisms of radioresistance in place, and some miRNAs are involved in the cellular response to ionizing radiation (IR). Here, we studied how IR affects the expression of miRNAs related to stemness in different molecular BC subtypes. Exposition of BC cells to radiation doses of 2, 4, or 6 Gy affected their phenotype, functional characteristics, pluripotency gene expression, and in vivo tumorigenic capacity. This held true for various molecular subtypes of BC cells (classified by ER, PR and HER‐2 status), and for BC cells either plated in monolayer, or being in suspension as mammospheres. However, the effect of IR on the expression of eight stemness‐ and radioresistance‐related miRNAs (miR‐210, miR‐10b, miR‐182, miR‐142, miR‐221, miR‐21, miR‐93, miR‐15b) varied, depending on cell line subpopulation and clinicopathological features of BC patients. Therefore, clinicopathological features and, potentially also, chemotherapy regimen should be both taken into consideration, for determining a potential miRNA signature by liquid biopsy in BC patients treated with RT. Personalized and precision RT dosage regimes could improve the prognosis, treatment, and survival of BC patients.

Prognostic role of microRNAs in breast cancer: A systematic review

MicroRNAs (miRNAs) have been found to play an important role in breast cancer, functioning either as potential oncogenes or tumor suppressor genes, but their role in the prognosis of patients remains unclear. The aim of the present review study is to highlight recent preclinical and clinical studies performed on both circulating and tissue-specific miRNAs and their potential role as prognostic markers in breast cancer. We systematically searched the PubMed database to explore the prognostic value of miRNAs in breast cancer. After performing the literature search and review, 117 eligible studies were identified. We found that 110 aberrantly expressed miRNAs have been associated with prognosis in breast cancer. In conclusion, the collective data presented in this review indicate that miRNAs could serve as novel prognostic tools in breast cancer, while the clinical application of these findings has yet to be verified.

Circulating microRNA-301 as a promising diagnostic biomarker of hepatitis C virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a serious consequence of persistent hepatitis C virus (HCV) infection and represents one of the most aggressive neoplasms globally. The implication of microRNA-301 (miR-301) in the initiation and progression of different types of cancers has been proved. We aimed to assess circulating microRNA-301 as possible biomarker for the early detection of HCC in patients with chronic HCV infection. miR-301 expression levels were estimated in plasma samples of 42 patients with newly diagnosed HCV-related HCC, 48 chronically HCV infected patients with liver cirrhosis and 40 healthy individuals by reverse transcription-quantitative polymerase chain reaction technique. In comparison with chronically HCV infected patients and healthy controls, miR-301 expression levels were significantly increased in HCC patients (P < 0.001). miR-301 levels distinguished HCC patients from chronic HCV patients, with area under the receiver-operating characteristic curve of 0.89 (95% CI 0.82-0.96), the sensitivity and the specificity were 78.57% and 89.58% respectively. Moreover, miR-301 levels were significantly linked with tumor size (P = 0.014), serum levels of alpha-fetoprotein (AFP) (P = 0.028) and Barcelona Clinic Liver Cancer (BCLC) score (P = 0.003). These results reveal that miR-301 can serve as a promising non-invasive biomarker for diagnosis of HCC in chronically HCV infected patients.

Topoisomerase I activity and sensitivity to camptothecin in breast cancer-derived cells: a comparative study

Background

Camptothecin (CPT) and its derivatives are currently used as second- or third-line treatment for patients with endocrine-resistant breast cancer (BC). These drugs convert nuclear enzyme DNA topoisomerase I (TOP1) to a cell poison with the potential to damage DNA by increasing the half-life of TOP1-DNA cleavage complexes (TOP1cc), ultimately resulting in cell death. In small and non-randomized trials for BC, researchers have observed extensive variation in CPT response rates, ranging from 14 to 64%. This variability may be due to the absence of reliable selective parameters for patient stratification. BC cell lines may serve as feasible models for generation of functional criteria that may be used to predict drug sensitivity for patient stratification and, thus, lead to more appropriate applications of CPT in clinical trials. However, no study published to date has included a comparison of multiple relevant parameters and CPT response across cell lines corresponding to specific BC subtypes.

Method

We evaluated the levels and possible associations of seven parameters including the status of the TOP1 gene (i.e. amplification), TOP1 protein expression level, TOP1 activity and CPT susceptibility, activity of the tyrosyl-DNA phosphodiesterase 1 (TDP1), the cellular CPT response and the cellular growth rate across a representative panel of BC cell lines, which exemplifies three major BC subtypes: Luminal, HER2 and TNBC.

Results

In all BC cell lines analyzed (without regard to subtype classification), we observed a significant overall correlation between growth rate and CPT response. In cell lines derived from Luminal and HER2 subtypes, we observed a correlation between TOP1 gene copy number, TOP1 activity, and CPT response, although the data were too limited for statistical analyses. In cell lines representing Luminal and TNBC subtypes, we observed a direct correlation between TOP1 protein abundancy and levels of enzymatic activity. In all three subtypes (Luminal, HER2, and TNBC), TOP1 exhibits approximately the same susceptibility to CPT. Of the three subtypes examined, the TNBC-like cell lines exhibited the highest CPT sensitivity and were characterized by the fastest growth rate. This indicates that breast tumors belonging to the TNBC subtype, may benefit from treatment with CPT derivatives.

Conclusion

TOP1 activity is not a marker for CPT sensitivity in breast cancer.

Prediction of clusters of miRNA binding sites in mRNA candidate genes of breast cancer subtypes

The development of breast cancer (BC) subtypes is controlled by distinct sets of candidate genes, and the expression of these genes is regulated by the binding of their mRNAs with miRNAs. Predicting miRNA associations and target genes is thus essential when studying breast cancer. The MirTarget program identifies the initiation of miRNA binding to mRNA, the localization of miRNA binding sites in mRNA regions, and the free energy from the binding of all miRNA nucleotides with mRNA. Candidate gene mRNAs have clusters (miRNA binding sites with overlapping nucleotide sequences). mRNAs of EPOR, MAZ and NISCH candidate genes of the HER2 subtype have clusters, and there are four clusters in mRNAs of MAZ, BRCA2 and CDK6 genes. Candidate genes of the triple-negative subtype are targets for multiple miRNAs. There are 11 sites in CBL mRNA, five sites in MMP2 mRNA, and RAB5A mRNA contains two clusters in each of the three sites. In SFN mRNA, there are two clusters in three sites, and one cluster in 21 sites. Candidate genes of luminal A and B subtypes are targets for miRNAs: there are 21 sites in FOXA1 mRNA and 15 sites in HMGA2 mRNA. There are clusters of five sites in mRNAs of ITGB1 and SOX4 genes. Clusters of eight sites and 10 sites are identified in mRNAs of SMAD3 and TGFB1 genes, respectively. Organizing miRNA binding sites into clusters reduces the proportion of nucleotide binding sites in mRNAs. This overlapping of miRNA binding sites creates a competition among miRNAs for a binding site. From 6,272 miRNAs studied, only 29 miRNAs from miRBase and 88 novel miRNAs had binding sites in clusters of target gene mRNA in breast cancer. We propose using associations of miRNAs and their target genes as markers in breast cancer subtype diagnosis.

MicroRNAs and Epigenetics Strategies to Reverse Breast Cancer

Breast cancer is a sporadic disease with genetic and epigenetic components. Genomic instability in breast cancer leads to mutations, copy number variations, and genetic rearrangements, while epigenetic remodeling involves alteration by DNA methylation, histone modification and microRNAs (miRNAs) of gene expression profiles. The accrued scientific findings strongly suggest epigenetic dysregulation in breast cancer pathogenesis though genomic instability is central to breast cancer hallmarks. Being reversible and plastic, epigenetic processes appear more amenable toward therapeutic intervention than the more unidirectional genetic alterations. In this review, we discuss the epigenetic reprogramming associated with breast cancer such as shuffling of DNA methylation, histone acetylation, histone methylation, and miRNAs expression profiles. As part of this, we illustrate how epigenetic instability orchestrates the attainment of cancer hallmarks which stimulate the neoplastic transformation-tumorigenesis-malignancy cascades. As reversibility of epigenetic controls is a promising feature to optimize for devising novel therapeutic approaches, we also focus on the strategies for restoring the epistate that favor improved disease outcome and therapeutic intervention.

Hydrogel-Coated Microneedle Arrays for Minimally Invasive Sampling and Sensing of Specific Circulating Nucleic Acids from Skin Interstitial Fluid

Minimally invasive technologies that can sample and detect cell-free nucleic acid biomarkers from liquid biopsies have recently emerged as clinically useful for early diagnosis of a broad range of pathologies, including cancer. Although blood has so far been the most commonly interrogated bodily fluid, skin interstitial fluid has been mostly overlooked despite containing the same broad variety of molecular biomarkers originating from cells and surrounding blood capillaries. Emerging technologies to sample this fluid in a pain-free and minimally-invasive manner often take the form of microneedle patches. Herein, we developed microneedles that are coated with an alginate-peptide nucleic acid hybrid material for sequence-specific sampling, isolation, and detection of nucleic acid biomarkers from skin interstitial fluid. Characterized by fast sampling kinetics and large sampling capacity (∼6.5 μL in 2 min), this platform technology also enables the detection of specific nucleic acid biomarkers either on the patch itself or in solution after light-triggered release from the hydrogel. Considering the emergence of cell-free nucleic acids in bodily fluids as clinically informative biomarkers, platform technologies that can detect them in an automated and minimally invasive fashion have great potential for personalized diagnosis and longitudinal monitoring of patient-specific disease progression.

Exosomal miRNA-139 in cancer-associated fibroblasts inhibits gastric cancer progression by repressing MMP11 expression

Solid tumors consist of various types of stromal cells in addition to cancer cells. Cancer-associated fibroblasts (CAFs) are a major component of the tumor stroma and play an essential role in tumor progression and metastasis in a variety of malignancies, including gastric cancer. However, the effects of CAFs on gastric cancer cells' progression and metastasis are not well studied. Here we show that matrix metalloproteinase 11 (MMP11) in exosomes secreted from CAFs can be delivered into gastric cancer cells. Gastric CAFs promote gastric cancer cell migration partially through exosomal MMP11. Moreover, MMP11 is overexpressed in exosomes purified from plasma of gastric cancer patients and tumor tissues and associated with overall survival of gastric patients. We also find that MMP11 is negatively regulated by exosomal miR-139 in the CAFs of gastric cancer. Exosomal miR-139 inhibits tumor growth and metastasis of gastric cancer cells by decreasing the expression of MMP11 in vitro and in vivo. Thus, we propose that exosomal miR-139 derived from gastric CAFs could inhibit the progression and metastasis of gastric cancer by decreasing MMP11 in tumor microenvironment.

Identification of prognostic biomarkers for breast cancer based on miRNA and mRNA co-expression network

PURPOSE

Breast cancer (BC) remains a serious health threat for women due to its high incidence and the trend of rejuvenation. Accumulating evidence has highlighted that microRNAs (miRNAs) and messenger RNAs (mRNAs) could play important roles in various biological processes involved in the pathogenesis of BC. The present study aimed to identify potential prognostic biomarkers associated with BC.

METHODS

Here, original gene expression profiles of patients with BC was downloaded from The Cancer Genome Atlas (TCGA) database. TargetScan, miRDB, and miRTarBase databases were used to predict the target genes of prognostic-related differentially expressed miRNAs (DEMs). Subsequently, functional enrichment analysis and topological analysis were performed on the overlaps of target genes and differentially expressed mRNAs (DEGs), and Kaplan-Meier analysis was used to predict prognosis-related target genes to identify prognostic biomarkers.

RESULTS

A total of 218 DEMs and 2222 DEGs were extracted in which eight miRNAs were associated with prognosis, and 278 target DEGs were screened out incorporated into functional enrichment analysis and protein-protein interaction network visualization studies. Additionally, five hub genes (CXCL12, IGF1, LEF1, MMP1, and RACGAP1) were observed as potential biomarkers for BC prognosis through survival analysis.

CONCLUSION

We performed a distinctive correlation analysis of miRNA-mRNA in BC patients, and identified eight miRNAs and five hub genes may be effective biomarkers for the prognosis of BC patients.

miR-1 inhibits the proliferation of breast cancer stem cells by targeting EVI-1

Purpose

Breast cancer stem cells (BCSCs) have been regarded as the key factor for treatment failure in breast cancer. The abnormal expression of miRNAs plays a significant role in different tumor types. However, the role of miR-1 in breast cancer remains poorly understood. The purpose of this study was to evaluate the effects of miR-1 on the proliferation and apoptosis of BCSCs.

Materials and methods

CD44⁺/CD24^−/low/epithelial-specific antigen⁺ BCSCs were isolated by flow cytometry. Real-time PCR and Western blotting were used to determine the expression of miRNAs, mRNAs, and epithelial–mesenchymal transition (EMT)-related genes. Cell proliferation and apoptosis were measured using the Cell Counting Kit-8 assay and Annexin V-fluorescein isothiocyanate flow cytometry, respectively. Luciferase reporter assay was used to verify whether miR-1 targeted ecotropic virus integration-1 (EVI-1). The role of miR-1 in breast cancer in vivo was evaluated using BCSCs xenograft mouse models.

Results

In this study, we demonstrated that miR-1 was significantly downregulated in breast cancer tissues compared to the adjacent non-tumor tissues. The luciferase reporter assay verified that EVI-1 was a direct target of miR-1, and upregulation of miR-1 negatively correlated with the expression of EVI-1 in BCSCs at both the transcriptional and posttranslational levels. Furthermore, overexpression of miR-1 inhibited BCSCs proliferation and promoted apoptosis, which was reversed by the overexpression of EVI-1. In addition, we demonstrated that aberrant expression of miR-1 could regulate EMT-related genes in BCSCs. Finally, immunohistochemical staining demonstrated that EVI-1 expression was decreased in BCSCs tumors following intra-tumoral miR-1 agomir treatment compared to the control group.

Conclusion

miR-1 can negatively regulate the expression of EVI-1 and, thus, affect BCSCs proliferation, apoptosis, and EMT-related markers. Taken together, these findings demonstrate that miR-1 could be employed as a therapeutic strategy in the treatment of breast cancer.

Epigenetic Crosstalk between the Tumor Microenvironment and Ovarian Cancer Cells: A Therapeutic Road Less Traveled

Metastatic dissemination of epithelial ovarian cancer (EOC) predominantly occurs through direct cell shedding from the primary tumor into the intra-abdominal cavity that is filled with malignant ascitic effusions. Facilitated by the fluid flow, cells distribute throughout the cavity, broadly seed and invade through peritoneal lining, and resume secondary tumor growth in abdominal and pelvic organs. At all steps of this unique metastatic process, cancer cells exist within a multidimensional tumor microenvironment consisting of intraperitoneally residing cancer-reprogramed fibroblasts, adipose, immune, mesenchymal stem, mesothelial, and vascular cells that exert miscellaneous bioactive molecules into malignant ascites and contribute to EOC progression and metastasis via distinct molecular mechanisms and epigenetic dysregulation. This review outlines basic epigenetic mechanisms, including DNA methylation, histone modifications, chromatin remodeling, and non-coding RNA regulators, and summarizes current knowledge on reciprocal interactions between each participant of the EOC cellular milieu and tumor cells in the context of aberrant epigenetic crosstalk. Promising research directions and potential therapeutic strategies that may encompass epigenetic tailoring as a component of complex EOC treatment are discussed.

Liquid biopsy and PCR-free ultrasensitive detection systems in oncology (Review)

In oncology, liquid biopsy is used in the detection of next-generation analytes, such as tumor cells, cell-free nucleic acids and exosomes in peripheral blood and other body fluids from cancer patients. It is considered one of the most advanced non-invasive diagnostic systems to enable clinically relevant actions and implement precision medicine. Medical actions include, but are not limited to, early diagnosis, staging, prognosis, anticipation (lead time) and the prediction of therapy responses, as well as follow-up. Historically, the applications of liquid biopsy in cancer have focused on circulating tumor cells (CTCs). More recently, this analysis has been extended to circulating free DNA (cfDNA) and microRNAs (miRNAs or miRs) associated with cancer, with potential applications for development into multi-marker diagnostic, prognostic and therapeutic signatures. Liquid biopsies avoid some key limitations of conventional tumor tissue biopsies, including invasive tumor sampling, under-representation of tumor heterogeneity and poor description of clonal evolution during metastatic dissemination, strongly reducing the need for multiple sampling. On the other hand, this approach suffers from important drawbacks, i.e., the fragmentation of cfDNA, the instability of RNA, the low concentrations of certain analytes in body fluids and the confounding presence of normal, as well as aberrant DNAs and RNAs. For these reasons, the analysis of cfDNA has been mostly focused on mutations arising in, and pathognomonicity of, tumor DNA, while the analysis of cfRNA has been mostly focused on miRNA patterns strongly associated with neoplastic transformation/progression. This review lists some major applicative areas, briefly addresses how technology is bypassing liquid biopsy limitations, and places a particular emphasis on novel, PCR-free platforms. The ongoing collaborative efforts of major international consortia are reviewed. In addition to basic and applied research, we will consider technological transfer, including patents, patent applications and available information on clinical trials aimed at verifying the potential of liquid biopsy in cancer.

Evaluation of the Expression Level and Hormone Receptor Association of miR-126 in Breast Cancer

Breast cancer is a major cause of cancer-related death in women worldwide. miRNAs are new players of breast tumorigenesis, used as diagnostic and prognostic biomarkers. Among various miRNAs, miR-126 has been proposed to have a tumor suppressive role in HER2 positive cancer. However, to have a better understanding of its role, further validation is required. The aim of this study was evaluating miR-126 expression level in breast cancer tissues and investigating its potential association with HER2, estrogen and progesterone receptors. miR-126 expression level was measured in 108 specimens including 78 malignant and 30 normal samples using RT-qPCR. The outcome was statistically analyzed. In silico studies were performed to find the potential mechanism of action, through which miR-126 imposes its function. Down-regulation of miR-126 was observed in tumor samples, as compared to the matched normal tissues. Down-regulation of miR-126 was also associated significantly with the absence of estrogen receptor in malignant samples. No association between miR-126 expression and HER2 status was observed. Our in silico analyses showed the possible role of Crk, PI₃K and Ras proto-oncogenes in breast cancer tumorigenesis. miR-126 is significantly down-regulated in breast cancer tissues. Statistically, it showed no correlation with HER2 positivity. However, the association between lower miR-126 and estrogen receptor negativity was observed.

New emerging roles of microRNAs in breast cancer

BACKGROUND

MicroRNAs constitute a large family of non-coding RNAs, which actively participate in tumorigenesis by regulating a set of mRNAs of distinct signaling pathways. An altered expression of these molecules has been found in different tumorigenic processes of breast cancer, the most common type of cancer in the female population worldwide.

PURPOSE

The objective of this review is to discuss how miRNAs become master regulators in breast tumorigenesis.

METHODS

An integrative review of miRNAs and breast cancer literature from the last 5 years was done on PubMed. We summarize recent works showing that the defects on the biogenesis of miRNAs are associated with different breast cancer characteristics. Then, we show several examples that demonstrate the link between cellular processes regulated by miRNAs and the hallmarks of breast cancer. Finally, we examine the complexity in the regulation of these molecules as they are modulated by other non-coding RNAs and the clinical applications of miRNAs as they could serve as good diagnostic and classification tools.

CONCLUSION

The information presented in this review is important to encourage new directed studies that consider microRNAs as a good tool to improve the diagnostic and treatment alternatives in breast cancer.

N-glycan signatures identified in tumor interstitial fluid and serum of breast cancer patients: association with tumor biology and clinical outcome

Particular N‐glycan structures are known to be associated with breast malignancies by coordinating various regulatory events within the tumor and corresponding microenvironment, thus implying that N‐glycan patterns may be used for cancer stratification and as predictive or prognostic biomarkers. However, the association between N‐glycans secreted by breast tumor and corresponding clinical relevance remain to be elucidated. We profiled N‐glycans by HILIC UPLC across a discovery dataset composed of tumor interstitial fluids (TIF, n = 85), paired normal interstitial fluids (NIF, n = 54) and serum samples (n = 28) followed by independent evaluation, with the ultimate goal of identifying tumor‐related N‐glycan patterns in blood of patients with breast cancer. The segregation of N‐linked oligosaccharides revealed 33 compositions, which exhibited differential abundances between TIF and NIF. TIFs were depleted of bisecting N‐glycans, which are known to play essential roles in tumor suppression. An increased level of simple high mannose N‐glycans in TIF strongly correlated with the presence of tumor infiltrating lymphocytes within tumor. At the same time, a low level of highly complex N‐glycans in TIF inversely correlated with the presence of infiltrating lymphocytes within tumor. Survival analysis showed that patients exhibiting increased TIF abundance of GP24 had better outcomes, whereas low levels of GP10, GP23, GP38, and coreF were associated with poor prognosis. Levels of GP1, GP8, GP9, GP14, GP23, GP28, GP37, GP38, and coreF were significantly correlated between TIF and paired serum samples. Cross‐validation analysis using an independent serum dataset supported the observed correlation between TIF and serum, for five of nine N‐glycan groups: GP8, GP9, GP14, GP23, and coreF. Collectively, our results imply that profiling of N‐glycans from proximal breast tumor fluids is a promising strategy for determining tumor‐derived glyco‐signature(s) in the blood. N‐glycans structures validated in our study may serve as novel biomarkers to improve the diagnostic and prognostic stratification of patients with breast cancer.

Involvement of aberrantly expressed microRNAs in the pathogenesis of head and neck squamous cell carcinoma

MicroRNAs (miRNAs) are small noncoding RNAs that act as fine-tuners of the post-transcriptional control of protein-coding or noncoding RNAs by repressing translation or cleaving RNA transcripts in a sequence-dependent manner in cells. Accumulating evidence have been indicated that aberrantly expressed miRNAs are deeply involved in human pathogenesis, including cancers. Surprisingly, these small, single-stranded RNAs (18-23 nucleotides) have been shown to function as antitumor or oncogenic RNAs in several types of cancer cells. A single miRNA has regulating hundreds or thousands of different mRNAs, and individual mRNA has been regulated by multiple different miRNAs in normal cells. Therefore, tightly controlled RNA networks can be disrupted by dysregulated of miRNAs in cancer cells. Investigation of novel miRNA-mediated RNA networks in cancer cells could provide new insights in the field of cancer research. In this review, we focus on head and neck squamous cell carcinoma (HNSCC) and discuss current findings of the involvement of aberrantly expressed miRNAs in the pathogenesis of HNSCC.

Exosomal miRNAs and miRNA dysregulation in cancer-associated fibroblasts

Purpose

The present review aimed to assess the role of exosomal miRNAs in cancer-associated fibroblasts (CAFs), normal fibroblasts (NFs), and cancer cells. The roles of exosomal miRNAs and miRNA dysregulation in CAF formation and activation were summarized.

Methods

All relevant publications were retrieved from the PubMed database, with key words such as CAFs, CAF, stromal fibroblasts, cancer-associated fibroblasts, miRNA, exosomal, exosome, and similar terms.

Results

Recent studies have revealed that CAFs, NFs, and cancer cells can secrete exosomal miRNAs to affect each other. Dysregulation of miRNAs and exosomal miRNAs influence the formation and activation of CAFs. Furthermore, miRNA dysregulation in CAFs is considered to be associated with a secretory phenotype change, tumor invasion, tumor migration and metastasis, drug resistance, and poor prognosis.

Conclusions

Finding of exosomal miRNA secretion provides novel insights into communication among CAFs, NFs, and cancer cells. MicroRNA dysregulation is also involved in the whole processes of CAF formation and function. Dysregulation of miRNAs in CAFs can affect the secretory phenotype of the latter cells.