The Role of Exosomal MicroRNAs in the Tumor Microenvironment of Breast Cancer

Mechanistic insights into cisplatin response in breast tumors: Molecular determinants and drug/nanotechnology-based therapeutic opportunities

Breast cancer continues to be a major global health challenge, driving the need for effective therapeutic strategies. Cisplatin, a powerful chemotherapeutic agent, is widely used in breast cancer treatment. However, its effectiveness is often limited by systemic toxicity and the development of drug resistance. This review examines the molecular factors that influence cisplatin response and resistance, offering crucial insights for the scientific community. It highlights the significance of understanding cisplatin resistance's genetic and epigenetic contributors, which could lead to more personalized treatment approaches. Additionally, the review explores innovative strategies to counteract cisplatin resistance, including combination therapies, nanoparticle-based drug delivery systems, and targeted therapies. These approaches are under intensive investigation and promise to enhance breast cancer treatment outcomes. This comprehensive discussion is a valuable resource to advance breast cancer therapeutics and address the challenge of cisplatin resistance.

Elevated extracellular vesicular Nm23-H1 subdues the pro-migratory potential of breast cancer cell-derived extracellular vesicles

Metastasis is a key determinant in cancer mortality which is often associated with decreased levels of Nm23-H1, a well-established metastasis suppressor. Despite lacking a secretion signal peptide, Nm23-H1 has been reported to be present in the extracellular space and enclosed within extracellular vesicles (EVs). While the presence of Nm23-H1 proteins in EVs released by cancer cells has been observed through proteomics profiling, the role of vesicular Nm23-H1 remains unclear. Here, we investigated the function of vesicular Nm23-H1 using MDA-MB-231 (highly metastatic, low Nm23-H1) and MCF-7 (low/non-metastatic, high Nm23-H1) breast cancer cell models. Our findings confirm that Nm23-H1 is indeed encapsulated within EVs, and its levels can be manipulated through overexpression and knockdown approaches. Functional assays revealed that EVs derived from MDA-MB-231 cells that contained high levels of Nm23-H1 exhibit impaired pro-migratory properties, suggesting that vesicular Nm23-H1 may act as a metastasis suppressor. Furthermore, EVs with increased levels of Nm23-H1 altered the transcript levels of multiple cancer-related genes in recipient cells and stimulated type I interferon signaling through STAT1 phosphorylation. These results suggest the existence of an unconventional signaling pathway mediated by the uptake of EVs enriched with Nm23-H1, which may contribute to the anti-metastatic effect of Nm23-H1 in the tumor microenvironment. Additionally, our study demonstrates that elevated Nm23-H1 levels can impact the abundance of various other proteins encapsulated within breast cancer cell-derived EVs, such as SUSD2 (Sushi Domain Containing 2) which can also modulate metastasis.

Impact of brain organoid-derived sEVs on metastatic adaptation and invasion of breast carcinoma cells through a microphysiological system

Brain metastases are common in triple-negative breast cancer (TNBC), suggesting a complex process of cancer spread. The mechanisms enabling TNBC cell adaptation and proliferation in the brain remain unclear. Small extracellular vesicles (sEVs) play a crucial role in communication between breast carcinoma cells and the brain. However, the lack of relevant models hinders understanding of sEV-mediated communication. The present study assesses the impact of brain organoid-derived sEVs (BO-sEVs) on various behaviours of the MDA-MB-231 cell line, chosen as a representative of TNBC in a 3D microfluidic model. Our results demonstrate that 150-200 nm sEVs expressing CD63, CD9, and CD81 from brain organoid media decrease MDA-MB-231 cell proliferation, enhance their wound-healing capacity, alter their morphology into more mesenchymal mode, and increase their stemness. BO-sEVs led to heightened PD-L1, CD49f, and vimentin levels of expression in MDA-MB-231 cells, suggesting an amplified immunosuppressive, stem-like, and mesenchymal phenotype. Furthermore, these sEVs also induced the expression of neural markers such as GFAP in carcinoma cells. The cytokine antibody profiling array also showed that BO-sEVs enhanced the secretion of MCP-1, IL-6, and IL-8 by MDA-MB-231 cells. Moreover, sEVs significantly enhance the migration and invasion of carcinoma cells toward brain organoids in a 3D organoid-on-a-chip system. Our findings emphasize the potential significance of metastatic site-derived sEVs as pivotal mediators in carcinoma progression and adaptation to the brain microenvironment, thereby unveiling novel therapeutic avenues.

MEG3-Mediated Oral Squamous-Cell-Carcinoma-Derived Exosomal miR-421 Activates Angiogenesis by Targeting HS2ST1 in Vascular Endothelial Cells

Exosomal microRNAs (miRNAs) from cancer cells play a key role in mediating the oral squamous cell carcinoma (OSCC) microenvironment. The objective of this study was to investigate how the long non-coding RNA (lncRNA) MEG3 affects OSCC angiogenesis through exosomal miR-421. Global miRNA microarray analysis and quantitative real-time PCR (qRT-PCR) were performed to determine the level of miRNAs in OSCC cell-derived exosomes. Cell migration, invasion, tube formation, immunohistochemistry, and hemoglobin concentrations were used to study the effects of exosomal miR-421 in angiogenesis. Western blotting was used to determine the expression level of HS2ST1 and VEGFR2-related downstream proteins. MiRNA array and qRT-PCR identified the upregulation of miR-421 in OSCC cell-derived exosomes. Furthermore, exosomal miR-421 can be taken up by human umbilical vein endothelial cells (HUVECs) and then target HS2ST1 through VEGF-mediated ERK and AKT phosphorylation, thereby promoting HUVEC migration, invasion, and tube formation. Additionally, forced expression of the lncRNA MEG3 in OSCC cells reduced exosomal miR-421 levels and then increased HS2ST1 expression, thereby reducing the VEGF/VEGFR2 pathway in HUVECs. Our results demonstrate a novel mechanism by which lncRNA MEG3 can act as a tumor suppressor and regulate endothelial angiogenesis through the exosomal miR-421/HS2ST1 axis, which provides a potential therapeutic strategy for OSCC angiogenesis.

The Multifaceted Role of miR-21 in Pancreatic Cancers

With the lack of specific signs and symptoms, pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at late metastatic stages, resulting in poor survival outcomes. Among various biomarkers, microRNA-21 (miR-21), a small non-coding RNA, is highly expressed in PDAC. By inhibiting regulatory proteins at the 3' untranslated regions (UTR), miR-21 holds significant roles in PDAC cell proliferation, epithelial-mesenchymal transition, angiogenesis, as well as cancer invasion, metastasis, and resistance therapy. We conducted a systematic search across major databases for articles on miR-21 and pancreatic cancer mainly published within the last decade, focusing on their diagnostic, prognostic, therapeutic, and biological roles. This rigorous approach ensured a comprehensive review of miR-21's multifaceted role in pancreatic cancers. In this review, we explore the current understandings and future directions regarding the regulation, diagnostic, prognostic, and therapeutic potential of targeting miR-21 in PDAC. This exhaustive review discusses the involvement of miR-21 in proliferation, epithelial-mesenchymal transition (EMT), apoptosis modulation, angiogenesis, and its role in therapy resistance. Also discussed in the review is the interplay between various molecular pathways that contribute to tumor progression, with specific reference to pancreatic ductal adenocarcinoma.

Mesenchymal stem cells-derived IL-6 promotes invasion and metastasis of oral squamous cell carcinoma via JAK-STAT3 signalling

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is often diagnosed with cervical lymph node metastasis. Mesenchymal stem cells (MSCs) and interleukin-6 (IL-6) signalling are considered to play important roles in promoting tumour malignancy. The detailed biological interaction of MSCs and IL-6 and the subsequent effect on OSCC metastasis remain largely unclear. This study aimed to determine the effects and molecular mechanism of MSCs-derived IL-6 on tumour invasion and metastasis.

SUBJECTS AND METHODS

The effects of MSC-derived IL-6 and tocilizumab on the proliferation, mobility, and epithelial-mesenchymal transition (EMT) of OSCC cells and potential pathways were detected in vitro. In addition, a murine xenograft model was generated to verify the biological mechanism in vivo.

RESULTS

The results showed that the expression of MSCs and EMT-related signals was increased in poorly differentiated OSCC tissues. MSCs released a higher level of IL-6 and promoted the proliferation, invasion, and metastasis of OSCC cells and solid neoplasms, which were activated by the downstream molecules JAK and STAT3.

CONCLUSIONS

The results indicated that MSCs-derived IL-6-promoted tumour invasion and metastasis via JAK-STAT3 signalling. Blockade of this pathway by tocilizumab may be a potential treatment to improve the prognosis and survival rate of patients with OSCC.

Biological Roles and Clinical Applications of Exosomes in Breast Cancer: A Brief Review

Breast cancer (BC) is a global health risk for women and has a high prevalence rate. The drug resistance, recurrence, and metastasis of BC affect patient prognosis, thus posing a challenge to scientists. Exosomes are extracellular vesicles (EVs) that originate from various cells; they have a double-layered lipid membrane structure and contain rich biological information. They mediate intercellular communication and have pivotal roles in tumor development, progression, and metastasis and drug resistance. Exosomes are important cell communication mediators in the tumor microenvironment (TME). Exosomes are utilized as diagnostic and prognostic biomarkers for estimating the treatment efficacy of BC and have the potential to function as tools to enable the targeted delivery of antitumor drugs. This review introduces recent progress in research on how exosomes influence tumor development and the TME. We also present the research progress on the application of exosomes as prognostic and diagnostic biomarkers and drug delivery tools.

Prospects for liquid biopsy using microRNA and extracellular vesicles in breast cancer

Among the analytes circulating in body fluids, microRNAs, a type of non-coding RNA and known to exist 2655 in primates, have attracted attention as a novel biomarker for cancer screening. MicroRNAs are signaling molecules with important gene expression regulatory functions that can simultaneously control many gene functions and multiple different pathways in living organisms. These microRNAs are transported in extracellular vesicles (EVs), which are lipid bilayers with 50-150 nm in diameter, and are used as communication tools between cells. Furthermore, the EVs that carry these microRNAs circulate in the bloodstream and have other important implications for understanding the pathogenesis and diagnosis of breast cancer. The greatest benefit from cancer screening is the reduction in breast cancer mortality rate through early detection. Other benefits include reduced incidence of breast cancer, improved quality of life, prognosis prediction, contribution to personalized medicine, and relative healthcare cost containment. This paper outlines the latest developments in liquid biopsy for breast cancer, especially focusing on microRNA and EV diagnostics.

The regulatory mechanisms of oncomiRs in cancer

Cancer development is a complex process that primarily results from the combination of genetic alterations and the dysregulation of major signalling pathways due to interference with the epigenetic machinery. As major epigenetic regulators, miRNAs are central players in the control of many key tumour development factors. These miRNAs have been classified as oncogenic miRNAs (oncomiRs) when they target tumour suppressor genes and tumour suppressor miRNAs (TS miRNAs) when they inhibit oncogene protein expression. Most of the mechanisms that modulate oncomiR expression are linked to transcriptional or posttranscriptional regulation. However, non-transcriptional processes, such as gene amplification, have been described as alternative processes that are responsible for increasing oncomiR expression. The current review summarises the different mechanisms controlling the upregulation of oncomiR expression in cancer cells and the tumour microenvironment (TME). Detailed knowledge of the mechanism underlying the regulation of oncomiR expression in cancer may pave the way for understanding the critical role of oncomiRs in cancer development and progression.

MicroRNAs mediated interaction of tumor microenvironment cells with breast cancer cells during bone metastasis

Breast cancer (BC) bone metastasis is primarily osteolytic and has limited therapeutic options. Metastasized BC cells prime the secondary environment in bone by forming a tumor niche, which favors their homing and colonization. The tumor microenvironment (TME) is primarily generated by the cancer cells. Bone TME is an intricate network of multiple cells, including altered bone, tumor, stromal, and immune cells. Recent findings highlight the significance of small non-coding microRNAs (miRNAs) in influencing TME during tumor metastasis. MiRNAs from TME-resident cells facilitate the interaction between the tumor and its microenvironment, thereby regulating the biological processes of tumors. These miRNAs can serve as oncogenes or tumor suppressors. Hence, both miRNA inhibitors and mimics are extensively utilized in pre-clinical trials for modulating the phenotypes of tumor cells and associated stromal cells. This review briefly summarizes the recent developments on the functional role of miRNAs secreted directly or indirectly from the TME-resident cells in facilitating tumor growth, progression, and metastasis. This information would be beneficial in developing novel targeted therapies for BC.

Plasma exosomes induce inflammatory immune response in patients with acute myocardial infarction

Exosomes are a kind of nanoscale extracellular vesicles with diameters of 30-100 nm and act as intracellular communication vehicles to influence cellular activities. Emerging pieces of evidence have indicated that exosomes play important roles in inflammation. However, the biological roles of plasma exosomes in acute myocardial infarction (AMI) patients have remained largely unexplored. In the current study, we found the plasma exosome levels were notably increased in patients with AMI in comparison with healthy controls (HCs), and AMI exosomes could induce endothelial cell injury. Furthermore, our data demonstrated that AMI exosomes triggered a pro-inflammatory immune response, at least partly depending on the activation of the NF-ĸB signalling. Together, AMI exosomes have pro-inflammatory properties and play a significant role in inflammation in AMI patients.

The effect of encomir-93 mimic transfection on the expression of miR-93 and PSA and androgen receptor in prostate cancer LNcap cell line

OBJECTIVES

Prostate cancer (PCa) is one of the most common cancers in men with high mortality rate which is a major concern for men's health. However, the molecular mechanisms remain poorly understood. miR-93 is an important oncogene which may have important function in prostate cancer.So, this study aimed to predict that encomir-93 mimic transfection on the expression of miR-93 and PSA and AR in prostate cancer LNcap cell line.

METHODS

Lymph node carcinoma of the prostate (LNCaP) was cultured and then miR-93 mimics was designed, synthesized and the transfected to LNCaP. The expression level of prostate-specific antigen (PSA) and androgen receptor (AR) was determined via Real-time PCR after treated with 15 pmol of miR-93 mimics.

RESULTS

miR-93 mimic transfection led to significant increase in PSA and AR expression in comparison with control group (p≤0.05).

CONCLUSIONS

The miR-93 and its target genes has important role in PCa progression via enhancement in PSA and AR expression. Further research on the function of the miR-93 and its target genes in tumorgenesis and progression PCa could be helpful for the treatment of prostate cancer.

Role of non‑coding RNAs in cartilage endplate (Review)

Cartilage endplate (CEP) degeneration is considered one of the major causes of intervertebral disc degeneration (IDD), which causes non-specific neck and lower back pain. In addition, several non-coding RNAs (ncRNAs), including long ncRNAs, microRNAs and circular RNAs have been shown to be involved in the regulation of various diseases. However, the particular role of ncRNAs in CEP remains unclear. Identifying these ncRNAs and their interactions may prove to be is useful for the understanding of CEP health and disease. These RNA molecules regulate signaling pathways and biological processes that are critical for a healthy CEP. When dysregulated, they can contribute to the development disease. Herein, studies related to ncRNAs interactions and regulatory functions in CEP are reviewed. In addition, a summary of the current knowledge regarding the deregulation of ncRNAs in IDD in relation to their actions on CEP cell functions, including cell proliferation, apoptosis and extracellular matrix synthesis/degradation is presented. The present review provides novel insight into the pathogenesis of IDD and may shed light on future therapeutic approaches.

The immunomodulatory role of exosomal microRNA networks in the crosstalk between tumor-associated myeloid-derived suppressor cells and tumor cells

Myeloid-derived suppressor cells (MDSCs) are considered a heterogeneous group of immature myeloid cells engaging in aggressive tumor progression and metastasis in the tumor microenvironment (TME) of patients diagnosed with cancer, through downregulation of anti-tumor immune responses. Exosomes are small vesicles carrying specific cargos, including proteins, lipids, and MicroRNA (miRNAs). Such exosomal miRNAs delivered by MDSCs and tumor cells are short noncoding RNAs mediating some of the immunosuppressive characteristics of MDSCs in the TME. However, when it comes to cancer diseases, how these miRNAs interact with MDSCs and encourage MDSCs differentiation and function need further investigations. In this review, we discuss MDSC-derived exosomal miRNAs and those derived from tumor cells (TDE) could modulate anti-tumor immunity and regulate the interaction between tumor cells and MDSCs in the TME. Afterward, we focus on dividing miRNAs, as an important substance interacting with MDSCs and tumor cells in the TME, into those have an immunosuppressive or stimulating effect not only on MDSCs expansion, differentiation, and suppressive function but also on tumor evasion.

Functional enhancement of exosomes derived from NK cells by IL-15 and IL-21 synergy against hepatocellular carcinoma cells: The cytotoxicity and apoptosis in vitro study

Exosomes are released by various cells, including natural killer (NK) cells and transport signaling molecules for the intercellular communication. Hepatocellular carcinoma (HCC), also known as primary liver cancer, is often inoperable and difficult to accurate diagnosis. Notably, the prognosis and underlying mechanisms of HCC are not fully understood. Exosomes-derived NK cells (NK-exos) express unique cytotoxic proteins with a killing ability in tumors and can easily penetrate tumor tissues to improve their targeting ability. NK cell functions, inducing cellular cytotoxicity are modulated by cytokines such as interleukin (IL)-15 and IL-21. However, the mechanisms and effects of cytokines-stimulated NK-exos for the treatment of liver cancer, including HCC, are not well known. In this study, we aimed to investigate the synergistic anti-tumor effects of NK-exos stimulated with IL-15 and IL-21 (NK-exos^IL-15/21) in Hep3B cells. Our findings revealed that NK-exos^IL-15/21 expressed cytotoxic proteins (perforin and granzyme B) and contained typical exosome markers (CD9 and CD63) within the size range of 100-150 nm. Moreover, we demonstrated that NK-exos^IL-15/21 induced the enhancement of cytotoxicity and apoptotic activity in Hep3B cells by activating the specific pro-apoptotic proteins (Bax, cleaved caspase 3, cleaved PARP, perforin, and granzyme B) and inhibiting the anti-apoptotic protein (Bcl-2). In summary, our results suggest that NK-exos^IL-15/21 regulate strong anti-tumor effects of HCC cells, by increasing the cytotoxicity and apoptosis through the activation of specific cytotoxic molecules.

Adapter dimer contamination in sRNA-sequencing datasets predicts sequencing failure and batch effects and hampers extracellular vesicle-sRNA analysis

Small RNA (sRNA) profiling of Extracellular Vesicles (EVs) by Next-Generation Sequencing (NGS) often delivers poor outcomes, independently of reagents, platforms or pipelines used, which contributes to poor reproducibility of studies. Here we analysed pre/post-sequencing quality controls (QC) to predict issues potentially biasing biological sRNA-sequencing results from purified human milk EVs, human and mouse EV-enriched plasma and human paraffin-embedded tissues. Although different RNA isolation protocols and NGS platforms were used in these experiments, all datasets had samples characterized by a marked removal of reads after pre-processing. The extent of read loss between individual samples within a dataset did not correlate with isolated RNA quantity or sequenced base quality. Rather, cDNA electropherograms revealed the presence of a constant peak whose intensity correlated with the degree of read loss and, remarkably, with the percentage of adapter dimers, which were found to be overrepresented sequences in high read-loss samples. The analysis through a QC pipeline, which allowed us to monitor quality parameters in a step-by-step manner, provided compelling evidence that adapter dimer contamination was the main factor causing batch effects. We concluded this study by summarising peer-reviewed published workflows that perform consistently well in avoiding adapter dimer contamination towards a greater likelihood of sequencing success.

Identification of Exo-miRNAs: A Summary of the Efforts in Translational Studies Involving Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) accounts for about 10-15% of all breast cancers (BC) in the US and its diagnosis is associated with poor survival outcomes. A better understanding of the disease etiology is crucial to identify target treatment options to improve patient outcomes. The role of exo-miRNAs in TNBC has been studied for more than two decades. Although some studies have identified exo-miR candidates in TNBC using clinical samples, consensus regarding exo-miR candidates has not been achieved. The purpose of this review is to gather information regarding exo-miR candidates reported in TNBC translational studies along with the techniques used to isolate and validate the potential targets. The techniques suggested in this review are based on the use of commercially available materials for research and clinical laboratories. We expect that the information included in this review can add additional value to the recent efforts in the development of a liquid biopsy to identify TNBC cases and further improve their survival outcomes.

Exosomal miRNAs in the Tumor Microenvironment of Multiple Myeloma

Multiple myeloma (MM) is a malignancy of plasma cells in the bone marrow and is characterized by the clonal proliferation of B-cells producing defective monoclonal immunoglobulins. Despite the latest developments in treatment, drug resistance remains one of the major challenges in the therapy of MM. The crosstalk between MM cells and other components within the bone marrow microenvironment (BME) is the major determinant of disease phenotypes. Exosomes have emerged as the critical drivers of this crosstalk by allowing the delivery of informational cargo comprising multiple components from miniature peptides to nucleic acids. Such material transfers have now been shown to perpetuate drug-resistance development and disease progression in MM. MicroRNAs(miRNAs) specifically play a crucial role in this communication considering their small size that allows them to be readily packed within the exosomes and widespread potency that impacts the developmental trajectory of the disease inside the tumor microenvironment (TME). In this review, we aim to provide an overview of the current understanding of the role of exosomal miRNAs in the epigenetic modifications inside the TME and its pathogenic influence on the developmental phenotypes and prognosis of MM.

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 Exosomes in Pancreatic Ductal Adenocarcinoma Progression and Their Potential as Biomarkers

Pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic malignancy, is an aggressive and lethal cancer with a dismal five-year survival rate. Despite remarkable improvements in cancer therapeutics, the clinical outcome of PDAC patients remains poor due to late diagnosis of the disease. This highlights the importance of early detection, wherein biomarker evaluation including exosomes would be helpful. Exosomes, small extracellular vesicles (sEVs), are cell-secreted entities with diameters ranging from 50 to 150 nm that deliver cellular contents (e.g., proteins, lipids, and nucleic acids) from parent cells to regulate the cellular processes of targeted cells. Recently, an increasing number of studies have reported that exosomes serve as messengers to facilitate stromal-immune crosstalk within the PDAC tumor microenvironment (TME), and their contents are indicative of disease progression. Moreover, evidence suggests that exosomes with specific surface markers are capable of distinguishing patients with PDAC from healthy individuals. Detectable exosomes in bodily fluids (e.g., blood, urine, saliva, and pancreatic juice) are omnipresent and may serve as promising biomarkers for improving early detection and evaluating patient prognosis. In this review, we shed light on the involvement of exosomes and their cargos in processes related to disease progression, including chemoresistance, angiogenesis, invasion, metastasis, and immunomodulation, and their potential as prognostic markers. Furthermore, we highlight feasible clinical applications and the limitations of exosomes in liquid biopsies as tools for early diagnosis as well as disease monitoring. Taking advantage of exosomes to improve diagnostic capacity may provide hope for PDAC patients, although further investigation is urgently needed.

Biosensing chips for cancer diagnosis and treatment: a new wave towards clinical innovation

Recent technological advances in nanoscience and material designing have led to the development of point-of-care devices for biomolecule sensing and cancer diagnosis. In situ and portable sensing devices for bedside, diagnosis can effectively improve the patient’s clinical outcomes and reduce the mortality rate. Detection of exosomal RNAs by immuno-biochip with increased sensitivity and specificity to diagnose cancer has raised the understanding of the tumor microenvironment and many other technology-based biosensing devices hold great promise for clinical innovations to conquer the unbeatable fort of cancer metastasis. Electrochemical biosensors are the most sensitive category of biomolecule detection sensors with significantly low concentrations down to the atomic level. In this sense, this review addresses the recent advances in cancer detection and diagnosis by developing significant biological sensing devices that are believed to have better sensing potential than existing facilities.

MicroRNAs, Key Regulators in Glioma Progression as Potential Therapeutic Targets for Chinese Medicine

Gliomas are tumors of the primary central nervous system associated with poor prognosis and high mortality. The 5-year survival rate of patients with gliomas received surgery combined with chemotherapy or radiotherapy does not exceed 5%. Although temozolomide is commonly used in the treatment of gliomas, the development of resistance limits its use. MicroRNAs are non-coding RNAs involved in numerous processes of glioma cells, such as proliferation, migration and apoptosis. MicroRNAs regulate cell cycle, PI3K/AKT signal pathway, and target apoptosis-related genes (e.g., BCL6), angiogenesis-related genes (e.g., VEGF) and other related genes to suppress gliomas. Evidence illustrates that microRNAs can regulate the sensitivity of gliomas to temozolomide, cisplatin, and carmustine, thereby enhancing the efficacy of these agents. Moreover, traditional Chinese medicine (e.g., tanshinone IIA, xanthohumol, and curcumin) exert antiglioma effects by regulating the expression of microRNAs, and then microRNAs inhibit gliomas through influencing the process of tumors by targeting certain genes. In this paper, the mechanisms through which microRNAs regulate the sensitivity of gliomas to therapeutic drugs are described, and traditional Chinese medicine that can suppress gliomas through microRNAs are discussed. This review aims to provide new insights into the traditional Chinese medicine treatment of gliomas.

OncomiRs as noncoding RNAs having functions in cancer: Their role in immune suppression and clinical implications

Currently, microRNAs have been established as central players in tumorigenesis, but above all, they have opened an important door for our understanding of immune and tumor cell communication. This dialog is largely due to onco-miR transfer from tumor cells to cells of the tumor microenvironment by exosome. This review outlines recent advances regarding the role of oncomiRs in enhancing cancer and how they modulate the cancer-related immune response in the tumor immune microenvironment.

MicroRNAs (miRNAs) are a type of noncoding RNA that are important posttranscriptional regulators of messenger RNA (mRNA) translation into proteins. By regulating gene expression, miRNAs enhance or inhibit cancer development and participate in several cancer biological processes, including proliferation, invasion metastasis, angiogenesis, chemoresistance and immune escape. Consistent with their widespread effects, miRNAs have been categorized as oncogenes (oncomiRs) or tumor suppressor (TS) miRNAs. MiRNAs that promote tumor growth, called oncomiRs, inhibit messenger RNAs of TS genes and are therefore overexpressed in cancer. In contrast, TS miRNAs inhibit oncogene messenger RNAs and are therefore underexpressed in cancer. Endogenous miRNAs regulate different cellular pathways in all cell types. Therefore, they are not only key modulators in cancer cells but also in the cells constituting their microenvironments. Recently, it was shown that miRNAs are also involved in intercellular communication. Indeed, miRNAs can be transferred from one cell type to another where they regulate targeted gene expression. The primary carriers for the transfer of miRNAs from one cell to another are exosomes. Exosomes are currently considered the primary carriers for communication between the tumor and its surrounding stromal cells to support cancer progression and drive immune suppression. Exosome and miRNAs are seen by many as a hope for developing a new class of targeted therapy. This review outlines recent advances in understanding the role of oncomiRs in enhancing cancer and how they promote its aggressive characteristics and deeply discusses the role of oncomiRs in suppressing the anticancer immune response in its microenvironment. Additionally, further understanding the mechanism of oncomiR-related immune suppression will facilitate the use of miRNAs as biomarkers for impaired antitumor immune function, making them ideal immunotherapy targets.

Novel secretion modification region (SMR) peptide exhibits anti-metastatic properties in human breast cancer cells

Breast cancer is the second leading cause of cancer-related mortality in women worldwide, with nearly 90% attributed to metastatic progression. Exosomes containing epithelial–mesenchymal transition (EMT) ‘programs’ transmit pro-metastatic phenotypes. Our group discovered and developed a novel anti-cancer SMR peptide that antagonizes breast cancer cell exosome release resulting in cell cycle arrest and tumor growth suppression. This study aims to evaluate the anti-metastatic capabilities of the SMR peptide, focusing on exosomes and EMT. Breast cancer cell lines MDA-MB-231 and MCF-7 were treated with the SMRwt peptide, and the following assays were performed: cell wound-healing, migration, invasion. The SMRwt peptide consists of the following amino acid sequence VGFPVAAVGFPVDYKDDDDK and contains the SMR domain (⁶⁶VGFPV⁷⁰) of the HIV-1 Nef protein. Western blot analysis detected epithelial and mesenchymal markers to evaluate EMT progression. Extracellular vesicle type and quantity were assessed through NanoSight analysis. Mortalin and Vimentin knockdown was achieved through antibody targeting and miRNAs. Data gathered demonstrated that the SMR peptide interacts with Mortalin and Vimentin to inhibit pro-EMT exosome release and induce EMT tumor suppressor protein expression. Specifically, SMRwt treatment reduced mesenchymal markers Mortalin and Vimentin expression, while the epithelial marker E-cadherin expression was increased in breast cancer cells and breast cancer-derived exosomes. The SMR peptide specificity was identified as no effect was observed for MCF-10A exosome release or function. Direct Mortalin knockdown paralleled the results of SMR peptide treatment with an effective blockade of breast cancer cell migration. Conversely, the invasion assay differed between breast cancer cell lines with invasion blocked for in MCF-7 but not in MDA-MB-231. These results reinforce the therapeutic value of targeting breast cancer exosome release and reinforce Mortalin and Vimentin as critical regulators and therapeutic targets in breast cancer cell progression, EMT, and metastatic potential. A greater understanding of the SMR peptide mechanism of action will benefit the therapeutic design of anti-metastatic agents.

Cancer Stem Cells and Circulatory Tumor Cells Promote Breast Cancer Metastasis

Breast cancer (BC) is a highly metastatic, pathological cancer that significantly affects women worldwide. The mortality rate of BC is related to its heterogeneity, aggressive phenotype, and metastasis. Recent studies have highlighted that the tumor microenvironment (TME) is critical for the interplay between metastasis mediators in BC. BC stem cells, tumor-derived exosomes, circulatory tumor cells (CTCs), and signaling pathways dynamically remodel the TME and promote metastasis. This review examines the cellular and molecular mechanisms governing the epithelial to mesenchymal transition (EMT) that facilitate metastasis. This review also discusses the role of cancer stem cells (CSCs), tumor-derived exosomes, and CTs in promoting BC metastasis. Furthermore, the review emphasizes major signaling pathways that mediate metastasis in BC. Finally, the interplay among CSCs, exosomes, and CTCs in mediating metastasis have been highlighted. Therefore, understanding the molecular cues that mediate the association of CSCs, exosomes, and CTCs in TME helps to optimize systemic therapy to target metastatic BC.

Exosomal MicroRNA Analyses in Esophageal Squamous Cell Carcinoma Cell Lines

Exosomal miRNAs have been studied in various cancers as minimally invasive biomarkers. This study aimed to investigate the potential of exosomal microRNAs (miRNAs) as biomarkers for esophageal squamous cell carcinoma (ESCC). Exosomes were isolated from cultures of esophageal epithelial cell and ESCC cell lines using ExoDisc, and exosomal miRNAs were detected via miRNA sequencing. Of the differentially expressed 14 miRNAs, the top 2 up-regulated miRNAs (miR-205-5p and miR-429) and top 2 down-regulated miRNAs (miR-375-3p and miR-483-3p) were selected as ESCC target miRNAs. Four selected exosomal miRNAs were validated in the plasma of 20 healthy controls (HCs) and 40 ESCC patients via quantitative reverse transcription-polymerase chain reaction. The expression of plasma exosomal miR-205-5p and miR-429 significantly increased, while that of plasma exosomal miR-375-3p was significantly reduced in ESCC patients compared to that in HCs. At cut-off values of 5.04, 2.564, and 0.136, the sensitivity and specificity for the diagnosis of ESCC were 72.5% and 70.0% for miR-205-5p, 60.0% and 60.0% for miR-429, and 65.0% and 65.0% for miR-375-3p, respectively. Based on the exosomal miRNAs identified in ESCC cell lines, our study demonstrated that plasma exosomal miR-205-5p, miR-429, and miR-375-3p could serve as potential biomarkers for ESCC diagnosis.

MicroRNAs miR-142-5p, miR-150-5p, miR-320a-3p, and miR-4433b-5p in Serum and Tissue: Potential Biomarkers in Sporadic Breast Cancer

Breast cancer (BC) is a heterogeneous disease, and establishing biomarkers is essential to patient management. We previously described that extracellular vesicle–derived miRNAs (EV-miRNAs) miR-142-5p, miR-150-5p, miR-320a, and miR-4433b-5p in serum discriminated BC from control samples, either alone or combined in a panel. Using these previously described markers, we intend to evaluate whether the same markers identified in EVs are also potential biomarkers in tissue and serum. Expression analysis using RT-qPCR was performed using serum of 67 breast cancer patients (BC-S), 19 serum controls (CT), 83 fresh tumor tissues (BC-T), and 29 adjacent nontumor tissue samples (NT). In addition, analysis from The Cancer Genome Atlas (TCGA) data (832 BC-T and 136 NT) was performed. In all comparisons, we found concordant high expression levels of miR-320a and miR-4433b-5p in BC-S compared to CT in both EVs and cell-free miRNAs (cf-miRNAs). Although miR-150-5p and miR-142-5p were not found to be differentially expressed in serum, panels including these miRNAs improved sensitivity and specificity, supporting our previous findings in EVs. Fresh tissue and data from the TCGA database had, in most comparisons, an opposite behavior when compared to serum and EVs: lower levels of all miRNAs in BC-T than those in NT samples. TCGA analyses revealed reduced expression levels of miR-150-5p and miR-320a-3p in BC-T than those in NT samples and the overexpression of miR-142-5p in BC-T, unlike our RT-qPCR results from tissue in the Brazilian cohort. The fresh tissue analysis showed that all miRNAs individually could discriminate between BC-T and NT in the Brazilian cohort, with high sensitivity and sensibility. Furthermore, combining panels showed higher AUC values and improved sensitivity and specificity. In addition, lower levels of miR-320a-3p in serum were associated with poor overall survival in BC Brazilian patients. In summary, we observed that miR-320a and miR-4433b-5p distinguished BC from controls with high specificity and sensibility, regardless of the sample source. In addition, lower levels of miR-150-5p and higher levels of miR-142-5p were statistically significant biomarkers in tissue, according to TCGA. When combined in panels, all combinations could distinguish BC patients from controls. These results highlight a potential application of these miRNAs as BC biomarkers.

miR-143-5p suppresses breast cancer progression by targeting the HIF-1α-related GLUT1 pathway

Breast cancer (BC) is a commonly identified life-threatening type of cancer and a major cause of death among women worldwide. Several microRNAs (miRs), including miR-143-5p, have been reported to be vital for regulating hallmarks of cancer; however, the effect of miR-143-5p on BC requires further exploration. The present study performed bioinformatics analysis on GSE42072 and GSE41922 datasets from the National Center for Biotechnology Information Gene Expression Omnibus (GEO) database to identify miR-143-5p expression patterns. Furthermore, miR-143-5p expression was detected in BC cell lines and tissues via reverse transcription-quantitative PCR. Post-transfection with miR-143-5p mimics, Cell Counting Kit-8, colony formation and Transwell assays were performed to explore the effects of miR-143-5p on BC cell proliferation, colony formation, and migration. The association of miR-143-5p with the hypoxia-inducible factor-1α (HIF-1α)-associated glucose transporter 1 (GLUT1) pathway was explored via western blotting, immunofluorescence and dual-luciferase reporter assay. The present study detected high expression of miR-143-5p in BC tissue of the GSE42072 and serum of the GSE41922 datasets by GEO chip analysis. Additionally, the expression levels of miR-143-5p were decreased in BC tissues compared with those in adjacent healthy tissues, and low miR-143-5p expression was associated with a poorer prognosis and shorter survival time in patients with BC. In vitro, miR-143-5p expression levels were decreased in BC cells, and transfection with miR-143-5p mimics suppressed BC cell proliferation, colony formation, migration. Furthermore, miR-143-5p targeted the HIF-1α-related GLUT1 pathway, and inhibited HIF-1α and GLUT1 expression. Additionally, HIF-1α agonists reversed the miR-143-5p-induced inhibition during tumorigenesis. In conclusion, miR-143-5p exhibited low expression in BC tissues, and suppressed BC cell proliferation, colony formation, migration. Moreover, the antitumor effects of miR-143-5p targeted the HIF-1α-related GLUT1 pathway.

Emerging Concepts on the Role of Extracellular Vesicles and Its Cargo Contents in Glioblastoma-Microglial Crosstalk

Glioblastoma multiforme is the most common, highly aggressive malignant brain tumor which is marked by highest inter- and intra-tumoral heterogeneity. Despite, immunotherapy, and combination therapies developed; the clinical trials often result into large number of failures. Often cancer cells are known to communicate with surrounding cells in tumor microenvironment (TME). Extracellular vesicles (EVs) consisting of diverse cargo mediates this intercellular communication and is believed to modulate the immune function against GBM. Tumor-associated microglia (TAM), though being the resident innate immune cell of CNS, is known to attain pro-tumorigenic M2 phenotype, and this immunomodulation is aided by extracellular vesicle-mediated transfer of oncogenic, immunomodulatory molecules. Besides, oncogenic proteins, long non-coding RNAs (lncRNAs), are believed to carry oncogenic potential, and therefore, understanding the mechanism leading to microglial dysregulation mediated by GBM-derived extracellular vesicle (GDEV) lncRNAs becomes crucial. This review focuses on current understanding of role of GDEV and lncRNA in microglial dysfunction and its potential as a therapeutic target.

Extracellular vesicles extracted from bone marrow mesenchymal stem cells carrying MicroRNA-342-3p inhibit the INHBA/IL13Rα2 axis to suppress the growth and metastasis of breast cancer

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BMSC-EVs carrying miR-342-3p could prevent breast cancer growth and metastasis by downregulating the INHBA/IL13Rα2 axis, highlighting a potential target for anti-cancer treatment for breast cancer.

Increasing focus has come to the role of extracellular vesicles (EVs) in various cancers. Hence, we designed this study to explore the mechanism whereby microRNA-342-3p (miR-342-3p)-containing EVs derived from BMSCs might affect breast cancer. MCF-7 breast cancer cell line was co-incubated with the EVs isolated from rat BMSCs, followed by alteration of miR-342-3p and INHBA expression. Microarray-based analyses predicted a possible regulatory mechanism involving miR-342-3p, INHBA, and IL13Rα2 in breast cancer, which was verified by luciferase reporter, RNA pull-down, and RIP assays. Besides, in order to evaluate the effects of miR-342-3p on the biological features of breast cancer cells in vitro and in vivo, we employed the scratch assay, Transwell assay, CCK-8 assay, and nude mouse tumorigenicity assay. miR-342-3p carried by BMSC-EVs was transferred into breast cancer cells through co-culture, which inhibited the proliferation and metastasis of breast cancer cells in vitro. miR-342-3p downregulated the expression of INHBA, which further repressed the expression of IL13Rα2. Finally, the in vivo experimental results revealed the inhibitory role of miR-342-3p in tumor growth and metastasis in nude mice. To sum up, BMSC-EVs carrying miR-342-3p could prevent breast cancer growth and metastasis by downregulating the INHBA/IL13Rα2 axis, highlighting a potential target for anti-cancer treatment for breast cancer.

Liquid biopsy: Exosomal microRNAs as novel diagnostic and prognostic biomarkers in cancer

BACKGROUND

Detecting cancer at an early stage before clinical manifestation could be an effective strategy to decrease cancer mortality. Thus, identifying liquid biopsy biomarkers with high efficacy could be a promising approach for non-invasive diagnosis of cancer.

MAIN TEXT

Liquid biopsies are increasingly used as a supplement to biopsy, as it enables disease progression to be detected months before clinical and radiographic confirmation. Many bodily fluids contain exosomal microRNAs (miRNAs) which could provide a new class of biomarkers for early and minimally invasive cancer diagnosis due to the stability of miRNAs in exosomes. In this review, we mainly focused on the exosomal miRNAs (liquid biopsy) as biomarkers in the diagnosis and prognosis of various cancers.

CONCLUSION

Exosomal miRNAs can be used as diagnostic and prognosis biomarkers that provide unique insights and a more dynamic perspective of the progression and therapeutic responses in various malignancies. Therefore, the development of novel and more sensitive technologies that exploit exosomal miRNAs should be a priority for cancer management.

The Landscape of PDK1 in Breast Cancer

Given that 3-phosphoinositide-dependent kinase 1 (PDK1) plays a crucial role in the malignant biological behaviors of a wide range of cancers, we review the influence of PDK1 in breast cancer (BC). First, we describe the power of PDK1 in cellular behaviors and characterize the interaction networks of PDK1. Then, we establish the roles of PDK1 in carcinogenesis, growth and survival, metastasis, and chemoresistance in BC cells. More importantly, we sort the current preclinical or clinical trials of PDK1-targeted therapy in BC and find that, even though no selective PDK1 inhibitor is currently available for BC therapy, the combination trials of PDK1-targeted therapy and other agents have provided some benefit. Thus, there is increasing anticipation that PDK1-targeted therapy will have its space in future therapeutic approaches related to BC, and we hope the novel approaches of targeted therapy will be conducive to ameliorating the dismal prognosis of BC patients.

Current Understanding of Exosomal MicroRNAs in Glioma Immune Regulation and Therapeutic Responses

Exosomes, the small extracellular vesicles, are released by multiple cell types, including tumor cells, and represent a novel avenue for intercellular communication via transferring diverse biomolecules. Recently, microRNAs (miRNAs) were demonstrated to be enclosed in exosomes and therefore was protected from degradation. Such exosomal miRNAs can be transmitted to recipient cells where they could regulate multiple cancer-associated biological processes. Accumulative evidence suggests that exosomal miRNAs serve essential roles in modifying the glioma immune microenvironment and potentially affecting the malignant behaviors and therapeutic responses. As exosomal miRNAs are detectable in almost all kinds of biofluids and correlated with clinicopathological characteristics of glioma, they might be served as promising biomarkers for gliomas. We reviewed the novel findings regarding the biological functions of exosomal miRNAs during glioma pathogenesis and immune regulation. Furthermore, we elaborated on their potential clinical applications as biomarkers in glioma diagnosis, prognosis and treatment response prediction. Finally, we summarized the accessible databases that can be employed for exosome-associated miRNAs identification and functional exploration of cancers, including glioma.

Blood-Derived Extracellular Vesicle-Associated miR-3182 Detects Non-Small Cell Lung Cancer Patients

Simple Summary

Lung cancer is the leading cause of cancer-related death worldwide as patients are burdened with incredibly poor prognosis. Low survival rates are primarily attributed to lack of early detection and, therefore, timely therapeutic interventions. Late diagnosis is essentially caused by absent and non-specific symptoms, and compounded by inadequate diagnostic tools. We show here that a lung cancer biomarker, based on a simple blood test, might provide promising advantages for diagnostic assessment. Small extracellular vesicles (sEVs) are miniscule messengers that carry cancer biomarkers and are easily detected in the blood. We identify that the abundance of a specific micro-RNA, miR-3182, in these sEVs can be detected in the blood of lung cancer patients but not in controls with benign lung conditions. This demonstrates the potential use of miR-3182 as a biomarker for lung cancer diagnosis.

Abstract

With five-year survival rates as low as 3%, lung cancer is the most common cause of cancer-related mortality worldwide. The severity of the disease at presentation is accredited to the lack of early detection capacities, resulting in the reliance on low-throughput diagnostic measures, such as tissue biopsy and imaging. Interest in the development and use of liquid biopsies has risen, due to non-invasive sample collection, and the depth of information it can provide on a disease. Small extracellular vesicles (sEVs) as viable liquid biopsies are of particular interest due to their potential as cancer biomarkers. To validate the use of sEVs as cancer biomarkers, we characterised cancer sEVs using miRNA sequencing analysis. We found that miRNA-3182 was highly enriched in sEVs derived from the blood of patients with invasive breast carcinoma and NSCLC. The enrichment of sEV miR-3182 was confirmed in oncogenic, transformed lung cells in comparison to isogenic, untransformed lung cells. Most importantly, miR-3182 can successfully distinguish early-stage NSCLC patients from those with benign lung conditions. Therefore, miR-3182 provides potential to be used for the detection of NSCLC in blood samples, which could result in earlier therapy and thus improved outcomes and survival for patients.

Small extracellular vesicles: from mediating cancer cell metastasis to therapeutic value in pancreatic cancer

Pancreatic cancer is a highly malignant tumor and, is extremely difficult to diagnose and treat. Metastasis is one of the critical steps in the development of cancer and uses cell to cell communication to mediate changes in the microenvironment. Small extracellular vesicles (sEVs)-carry proteins, nucleic acids and other bioactive substances, and are important medium for communication between cells. There are two primary steps in sVEs-mediated metastasis: communication between pancreatic cancer cells and their surrounding microenvironment; and the communication between primary tumor cells and distant organ cells in distant organs that promotes angiogenesis, reshaping extracellular matrix, forming immunosuppressive environment and other ways to form appropriate pre-metastasis niche. Here, we explore the mechanism of localization and metastasis of pancreatic cancer and use sEVs as early biomarkers for the detection and treatment of pancreatic cancer. Video Abstract.

DNase I-assisted 2'-O-methyl molecular beacon for amplified detection of tumor exosomal microRNA-21

An end-modified 2'-O-methyl molecular beacon (eMB) with unique nuclease resistance was designed and prepared. The eMB can resist the enzymatic digestion by DNase I, which would otherwise occur upon the hybridization of the eMB with a complementary sequence. As a result, the coupling use of eMBs and DNase I allows highly sensitive detection of miRNA with a limit of detection (LOD) of 2.5 pM. The analytical strategy was further used for detection of tumor exosomal microRNA-21, and down to 0.86 μg mL^-1 A375 exosomes were detected. Overall, the present method can effectively quantify tumor-derived exosomes for cancer diagnosis.

Molecular Mediators of RNA Loading into Extracellular Vesicles

In the last decade, an increasing number of studies have demonstrated that non-coding RNA (ncRNAs) cooperate in the gene regulatory networks with other biomolecules, including coding RNAs, DNAs and proteins. Among them, microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are involved in transcriptional and translation regulation at different levels. Intriguingly, ncRNAs can be packed in vesicles, released in the extracellular space, and finally internalized by receiving cells, thus affecting gene expression also at distance. This review focuses on the mechanisms through which the ncRNAs can be selectively packaged into extracellular vesicles (EVs).

Advances of Exosomal miRNAs in Breast Cancer Progression and Diagnosis

Breast cancer is one of the most commonly diagnosed malignancies and the leading cause of cancer death in women worldwide. Although many factors associated with breast cancer have been identified, the definite etiology of breast cancer is still unclear. In addition, early diagnosis of breast cancer remains challenging. Exosomes are membrane-bound nanovesicles secreted by most types of cells and contain a series of biologically important molecules, such as lipids, proteins, and miRNAs, etc. Emerging evidence shows that exosomes can affect the status of cells by transmitting substances and messages among cells and are involved in various physiological and pathological processes. In breast cancer, exosomes play a significant role in breast tumorigenesis and progression through transfer miRNAs which can be potential biomarkers for early diagnosis of breast cancer. This review discusses the potential utility of exosomal miRNAs in breast cancer progression such as tumorigenesis, metastasis, immune regulation and drug resistance, and further in breast cancer diagnosis.

Roles and mechanisms of exosomal non-coding RNAs in human health and diseases

Exosomes play a role as mediators of cell-to-cell communication, thus exhibiting pleiotropic activities to homeostasis regulation. Exosomal non-coding RNAs (ncRNAs), mainly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are closely related to a variety of biological and functional aspects of human health. When the exosomal ncRNAs undergo tissue-specific changes due to diverse internal or external disorders, they can cause tissue dysfunction, aging, and diseases. In this review, we comprehensively discuss the underlying regulatory mechanisms of exosomes in human diseases. In addition, we explore the current knowledge on the roles of exosomal miRNAs, lncRNAs, and circRNAs in human health and diseases, including cancers, metabolic diseases, neurodegenerative diseases, cardiovascular diseases, autoimmune diseases, and infectious diseases, to determine their potential implication in biomarker identification and therapeutic exploration.

MicroRNAs: Their Role in Metabolism, Tumor Microenvironment, and Therapeutic Implications in Head and Neck Squamous Cell Carcinoma

Simple Summary

Head and neck squamous cell carcinoma (HNSCC), which arises from the oral epithelium, is one of the most common cancers worldwide. Despite excellent diagnosis and treatment improvements, the mortality rate associated with HNSCC is still extremely high. Current data suggest that dysregulation of exosomes and metabolic abnormalities are involved in the initiation and progression of HNSCC. Thus, approaches for targeting exosomes in the tumor microenvironment and metabolic reprogramming pathways represent potential therapeutic strategies. Moreover, some miRNAs are thought to have significant functions in regulating the progression of HNSCC. The present article aims to summarize the current knowledge concerning the important miRNAs in both exosomes and cancer metabolism, as well as discuss future perspectives regarding their future diagnostic potential and treatment recommendations.

Abstract

MicroRNAs (miRNAs) are endogenous small non-coding RNA molecules that negatively regulate gene expression by binding to target mRNAs. Deregulated miRNAs can act as either oncogenic miRNAs or tumor suppressor miRNAs in controlling proliferation, differentiation, apoptosis, metastasis, epithelial–mesenchymal transition, and immune responses, which are all involved in the carcinogenesis process of HNSCC. Recent findings have shown that metabolic reprogramming is an important hallmark of cancer, which is necessary for malignant transformation and tumor development. Some reprogrammed metabolisms are believed to be required for HNSCC against an unfavorable tumor microenvironment (TME). The TME is composed of various cell types embedded in the altered extracellular matrix, among which exosomes, secreted by cancer cells, are one of the most important factors. Tumor-derived exosomes reshape the tumor microenvironment and play a crucial role in cell-to-cell communication during HNSCC development. Exosomes encapsulate many biomolecules, including miRNAs, circulate in body fluids, and can transmit intercellular regulatory messages to nearby and distant sites, which indicates that exosomal miRNAs have the potential to become non-invasive biomarkers. This review aims to clarify the functions of diverse miRNAs in HNSCC metabolic reprogramming and tumor-derived exosomes. In addition, it also emphasizes the potential role of miRNA as a biomarker in the diagnosis, prognosis, and treatment of HNSCC cancer.

Fibulin 2 Is Hypermethylated and Suppresses Tumor Cell Proliferation through Inhibition of Cell Adhesion and Extracellular Matrix Genes in Non-Small Cell Lung Cancer

Fibulins (FBLNs), interacting with cell adhesion receptors and extracellular matrix (ECM) components, play multiple roles in ECM structures and tissue functions. Abnormal expression of FBLN2, one of the fibulin family members, contributes to tumor initiation and development. However, the function of FBLN2 in human non-small cell lung cancer (NSCLC) has not yet been elucidated. In this study, we found that FBLN2 was downregulated in 9 out of 11 lung cancer cell lines compared to normal bronchial epithelial cells, which was associated with DNA hypermethylation. Primary lung squamous cell carcinoma expressed significantly more FBLN2 protein compared to adenocarcinoma (p = 0.047). Ectopic expression of FBLN2 led to decreased cell proliferation, migration and invasion, accompanied by inactivated MAPK/ERK and AKT/mTOR pathways, while FBLN2 siRNA knockdown resulted in an opposite biological behaviour in NSCLC cells. Additionally, overexpression of FBLN2 led to dysregulation of cell adhesion molecules, ECM markers and a panel of lysate/exosome-derived-microRNAs, which are involved in cell adhesion and ECM remodelling. Taken together, our data indicate that FBLN2 is methylated and exerts a tumor suppressor function through modulation of MAPK/ERK and AKT pathways and regulation of cell adhesion and ECM genes. Moreover, FBLN2 might be a potential biomarker for the sub-classification of NSCLC.

Exosomal miR-1275 Secreted by Prostate Cancer Cells Modulates Osteoblast Proliferation and Activity by Targeting the SIRT2/RUNX2 Cascade

Prostate cancer (PCa) is one of the most frequently diagnosed malignancies and the second leading cause of cancer mortality among men worldwide. Modulation of osteoblast activity is involved in PCa metastasis, and miR-1275 is also reported to regulate PCa metastasis; however, the association between cancer-derived exosomal miR-1275 and osteoblast activity is unclear. Here, we isolated exosomes from PC3-derived conditioned medium by ultracentrifugation. We found that miR-1275 could be transferred from PCa cells to osteoblasts via exosomes. Exosomal miR-1275 significantly accelerated the proliferation of osteoblasts and the expression levels of osteoblast-specific genes, such as osteocalcin (OCN), type I collagen (COL-1), and osteopontin (OPN). Moreover, exosomal miR-1275 increased the expression of RUNX2, a master modulator of osteoblast activity, by down-regulation of SIRT2, which in turn influenced the growth and activity of osteoblasts. Our findings indicate that PCa-derived exosomal miR-1275 promotes the proliferation and activity of osteoblasts via modulation of SIRT2/Runx2 signaling.

The Immunomodulation Potential of Exosomes in Tumor Microenvironment

Exosomes are lipid bilayer particles that originated from almost all types of cells and play an important role in intercellular communication. Tumor-derived exosomes contain large amounts of noncoding RNA, DNA, and proteins, which can be transferred into recipient cells as functional components in exosomes. These exosomal functional constituents depend on the originating cells, and it has been proved that types and numbers of exosomal components differ in cancer patients and healthy individuals. This review summarizes the role of tumor-derived exosomes in immunomodulation and discusses the application of exosomes in immunotherapy in cancers. Overall, exosomes isolated from cancer cells are turned out to promote immune evasion and interfere with immune responses in tumors through inducing apoptosis of CD8+ T cells, facilitating generation of Tregs, suppressing natural killer (NK) cell cytotoxicity, inhibiting maturation and differentiation of monocyte, and enhancing suppressive function of myeloid-derived suppressor cells (MDSCs). Mechanistically, exosomal functional components play a significant role in the immunomodulation in cancers. Moreover, based on the existing studies, exosomes could potentially serve as therapeutic delivery vehicles, noninvasive biomarkers, and immunotherapeutic vaccines for various types of cancers.

Key Factor Regulating Inflammatory Microenvironment, Metastasis, and Resistance in Breast Cancer: Interleukin-1 Signaling

Breast cancer is one of the top-ranked cancers for incidence and mortality worldwide. The biggest challenges in breast cancer treatment are metastasis and drug resistance, for which work on molecular evaluation, mechanism studies, and screening of therapeutic targets is ongoing. Factors that lead to inflammatory infiltration and immune system suppression in the tumor microenvironment are potential therapeutic targets. Interleukin-1 is known as a proinflammatory and immunostimulatory cytokine, which plays important roles in inflammatory diseases. Recent studies have shown that interleukin-1 cytokines drive the formation and maintenance of an inflammatory/immunosuppressive microenvironment through complex intercellular signal crosstalk and tight intracellular signal transduction, which were found to be potentially involved in the mechanism of metastasis and drug resistance of breast cancer. Some preclinical and clinical treatments or interventions to block the interleukin-1/interleukin-1 receptor system and its up- and downstream signaling cascades have also been proven effective. This study provides an overview of IL-1-mediated signal communication in breast cancer and discusses the potential of IL-1 as a therapeutic target especially for metastatic breast cancer and combination therapy and current problems, aiming at enlightening new ideas in the study of inflammatory cytokines and immune networks in the tumor microenvironment.

Breast invasive ductal carcinoma diagnosis with a three-miRNA panel in serum

Aim: Breast cancer, especially invasive ductal carcinoma (IDC), is the cause of a great clinical burden. miRNA could be considered as a noninvasive biomarkers for IDC diagnosis. Materials & methods: Two hundred and sixty participants (135 IDC patients and 125 healthy controls) were enrolled in a three-cohort study. The expression of 28 miRNAs in serum were detected with quantitative reverse transcription-PCR. Bioinformatic analysis was used for predicting the target genes of three selected miRNAs. Results: The expression level of seven miRNAs (miR-9-5p, miR-34b-3p, miR-1-3p, miR-146a-5p, miR-20a-5p, miR-34a-5p, miR-125b-5p) was discrepant at the validation cohort. Through statistical test, a three-miRNA panel (miR-9-5p, miR-34b-3p, miR-146a-5p) was significant for IDC diagnosis (AUC = 0.880, sensitivity = 86.25%, specificity = 81.25%). Conclusion: The three-miRNA panel in serum could be used as a noninvasive biomarker in the diagnosis of IDC.

Exosomal miR-193b-5p as a regulator of LPS-induced inflammation in dairy cow mammary epithelial cells

Exosomes are a type of extracellular vesicle that act as shuttles, transporting certain genetic information to other cells. MiRNA cargo within exosomes can regulate gene expression at the transcriptional level. The objective of this study was to investigate the exosomal miRNAs that regulate lipopolysaccharide (LPS)-induced inflammation in dairy cow mammary alveolar (Mac-T) cells. We found two exosome miRNAs upregulated and five exosomal miRNAs downregulated, respectively, in the LPS-stimulated Mac-T cells. MiR-193b-5p was upregulated 6.3-fold in the LPS-stimulated cell-derived exosome. Target prediction results showed that nuclear factor kappa B (NF-κB) inhibitor delta (NFKBID), transforming growth factor-beta 1 induced transcript 1 (TGFB1I1), interleukin 22 (IL-22), TNF receptor superfamily member 11b (TNFRSF11B), and Janus kinase 3 (JAK3) might be the main target genes of miR-193b-5p. After treatment of Mac-T cells with the miR-193b-5p mimic, the phosphorylation levels of inhibitor of nuclear factor-kappa Bα (IκBα) and p65 were upregulated, the level of IL-6 mRNA was upregulated, and IL-1β, TNF-α, and TGF-β mRNA levels were downregulated. After treatment of Mac-T cells with miR-193b-5p inhibitor, the phosphorylation levels of IκBα and p65 were downregulated. In summary, these findings provide strong evidence that exosomal miR-193b-5p could be a regulator of LPS-induced inflammation in Mac-T cells and reveal a new role of exosomal miRNAs in regulating dairy cow mastitis.

Integrated Analysis of mRNA-seq and miRNA-seq to Identify c-MYC, YAP1 and miR-3960 as Major Players in the Anticancer Effects of Caffeic Acid Phenethyl Ester in Human Small Cell Lung Cancer Cell Line

BACKGROUND

Caffeic Acid Phenethyl Ester (CAPE), an active extract of propolis, has recently been reported to have broad applications in various cancers. However, the effects of CAPE on Small Cell Lung Cancer (SCLC) are largely unknown. Therefore, the aim of this study was to determine the anti-proliferative effect of CAPE and explore the underlying molecular mechanisms in SCLC cells using high-throughput sequencing and bioinformatics analysis.

METHODS

Small-cell lung cancer H446 cells were treated with CAPE, and cell proliferation and apoptosis were then assessed. Additionally, the regulation mediated by miR-3960 after CAPE treatment was explored and the altered signaling pathways were predicted in a bioinformatics analysis.

RESULTS

CAPE significantly inhibited cell proliferation and induced apoptosis. CAPE decreased the expression of Yes-Associated Protein 1 (YAP1) and cellular myelocytomatosis oncogene (c-MYC) protein. Moreover, the upregulation of miR-3960 by CAPE contributed to CAPE-induced apoptosis. The knockdown of miR-3960 decreased the CAPE-induced apoptosis.

CONCLUSION

We demonstrated the anti-cancer effect of CAPE in human SCLC cells and studied the mechanism by acquiring a comprehensive transcriptome profile of CAPE-treated cells.