Exosomal miR-19a and IBSP cooperate to induce osteolytic bone metastasis of estrogen receptor-positive breast cancer

Comprehensive analysis of abnormal methylation modification differential expression mRNAs between low-grade and high-grade intervertebral disc degeneration and its correlation with immune cells

BACKGROUND

Intervertebral disc degeneration (IDD) is an important cause of low back pain. The aim of this study is to identify the potential molecular mechanism of abnormal methylation-modified DNA in the progression of IDD, hoping to contribute to the diagnosis and management of IDD.

METHODS

Low-grade IDD (grade I-II) and high-grade IDD (grade III-V) data were downloaded from GSE70362 and GSE129789 datasets. The abnormally methylated modified differentially expressed mRNAs (DEmRNAs) were identified by differential expression analysis (screening criteria were p < .05 and |logFC| > 1) and differential methylation analysis (screening criteria were p < .05 and |δβ| > 0.1). The classification models were constructed, and the receiver operating characteristic analysis was also carried out. In addition, functional enrichment analysis and immune correlation analysis were performed and the miRNAs targeted for the abnormally methylated DEmRNAs were predicted. Finally, expression validation was performed using real-time PCR.

RESULTS

Compared with low-grade IDD, seven abnormal methylation-modified DEmRNAs (AOX1, IBSP, QDPR, ABLIM1, CRISPLD2, ACTC1 and EMILIN1) were identified in high-grade IDD, and the classification models of random forests (RF) and support vector machine (SVM) were constructed. Moreover, seven abnormal methylation-modified DEmRNAs and classification models have high diagnostic accuracy (area under the curve [AUC] > 0.8). We also found that AUC values of single abnormal methylation-modified DEmRNA were all lower than those of RF and SVM classification models. Pearson correlation analysis found that macrophages M2 and EMILIN1 had significant negative correlation, while macrophages M2 and IBSP had significant positive correlation. In addition, four targeted relationship pairs (hsa-miR-4728-5p-QDPR, hsa-miR-4533-ABLIM1, hsa-miR-4728-5p-ABLIM1 and hsa-miR-4534-CRISPLD2) and multiple signalling pathways (for example, PI3K-AKT signalling pathway, osteoclast differentiation and calcium signalling pathway) were also identified that may be involved in the progression of IDD.

CONCLUSION

The identification of abnormal methylation-modified DEmRNAs and the construction of classification models in this study were helpful for the diagnosis and management of IDD progression.

RAC1 inhibition ameliorates IBSP-induced bone metastasis in lung adenocarcinoma

Macrophage-to-osteoclast differentiation (osteoclastogenesis) plays an essential role in tumor osteolytic bone metastasis (BM), while its specific mechanisms remain largely uncertain in lung adenocarcinoma BM. In this study, we demonstrate that integrin-binding sialoprotein (IBSP), which is highly expressed in the cancer cells from bone metastatic and primary lesions of patients with lung adenocarcinoma, can facilitate BM and directly promote macrophage-to-osteoclast differentiation independent of RANKL/M-CSF. In vivo results further suggest that osteolytic BM in lung cancer specifically relies on IBSP-induced macrophage-to-osteoclast differentiation. Mechanistically, IBSP regulates the Rac family small GTPase 1 (Rac1)-NFAT signaling pathway and mediates the forward shift of macrophage-to-osteoclast differentiation, thereby leading to early osteolysis. Moreover, inhibition of Rac1 by EHT-1864 or azathioprine in mice models can remarkably alleviate IBSP-induced BM of lung cancer. Overall, our study suggests that tumor-secreted IBSP promotes BM by inducing macrophage-to-osteoclast differentiation, with potential as an early diagnostic maker for BM, and Rac1 can be the therapeutic target for IBSP-promoted BM in lung cancer.

Exosomal miRNAs: the tumor's trojan horse in selective metastasis

Organs of future metastasis are not passive receivers of circulating tumor cells, but are instead selectively and actively modified by the primary tumor before metastatic spread has even occurred. Tumors orchestrate a pre-metastatic program by conditioning distant organs to create microenvironments that foster the survival and proliferation of tumor cells before their arrival, thereby establishing pre-metastatic niches. Primary tumor-derived exosomes modulate these pre-metastatic niches, generating a permissive environment that facilitates the homing and expansion of tumor cells. Moreover, microRNAs have emerged as a key component of exosomal cargo, serving not only to induce the formation of pre-metastatic niches but also to prime these sites for the arrival and colonization of specific secondary tumor populations. Against this backdrop, this review endeavors to elucidate the impact of tumor-derived exosomal microRNAs on the genesis of their individualized pre-metastatic niches, with a view towards identifying novel means of specifying cancer metastasis and exploiting this phenomenon for cancer immunotherapy.

IBSP Promotes Breast Cancer Bone Metastasis and Proliferation via BMP-SMAD Signaling Pathway

BACKGROUND

Integrin-Binding Sialoprotein (IBSP) has been implicated in tumor progression across various cancers. However, the specific role of IBSP in breast cancer remains underexplored. There is a need to investigate the mechanisms by which IBSP influences breast cancer progression and its potential as a therapeutic target.

AIMS

This study aims to elucidate the role of IBSP in breast cancer, particularly its impact on tumor progression and its relationship with prognosis. We also seek to understand the underlying mechanisms, including the involvement of the BMP-SMAD signaling pathway, and to explore the potential of targeting IBSP for therapeutic interventions.

METHODS AND RESULTS

Overexpression of IBSP in breast cancer cells led to increased migration and invasion, whereas IBSP interference reduced these behaviors, indicating its role in enhancing tumor progression. Differentially expressed genes were significantly enriched in the BMP-SMAD signaling pathway, a critical pathway for osteogenic differentiation. Transcription Factor Binding: Dual luciferase reporter assays demonstrated that SMAD4 specifically binds to the IBSP promoter, establishing a regulatory link between SMAD4 and IBSP expression. Silencing IBSP (si-IBSP) mitigated the effects of SMAD4-induced tumor proliferation, confirming that IBSP acts as a downstream target of SMAD4 in the BMP signaling pathway.

CONCLUSION

Our study reveals that IBSP plays a significant role in breast cancer progression through the BMP-SMAD4 signaling pathway. Targeting IBSP could be a promising therapeutic strategy for breast cancer treatment. Further research into IBSP inhibitors may offer new avenues for improving treatment outcomes and managing breast cancer more effectively.

Impact of Extracellular Matrix-Related Genes on the Tumor Microenvironment and Prognostic Indicators in Esophageal Cancer: A Comprehensive Analytical Study

Esophageal cancer is a major global health challenge with a poor prognosis. Recent studies underscore the extracellular matrix (ECM) role in cancer progression, but the full impact of ECM-related genes on patient outcomes remains unclear. Our study utilized next-generation sequencing and clinical data from esophageal cancer patients provided by The Cancer Genome Atlas, employing the R package in RStudio for computational analysis. This analysis identified significant associations between patient survival and various ECM-related genes, including IBSP, LINGO4, COL26A1, MMP12, KLK4, RTBDN, TENM1, GDF15, and RUNX1. Consequently, we developed a prognostic model to predict patient outcomes, which demonstrated clear survival differences between high-risk and low-risk patient groups. Our comprehensive review encompassed clinical correlations, biological pathways, and variations in immune response among these risk categories. We also constructed a nomogram integrating clinical information with risk assessment. Focusing on the TENM1 gene, we found it significantly impacts immune response, showing a positive correlation with T helper cells, NK cells, and CD8+ T cells, but a negative correlation with neutrophils and Th17 cells. Gene Set Enrichment Analysis revealed enhanced pathways related to pancreatic beta cells, spermatogenesis, apical junctions, and muscle formation in patients with high TENM1 expression. This research provides new insights into the role of ECM genes in esophageal cancer and informs future research directions.

Immune mediated support of metastasis: Implication for bone invasion

Bone is a common organ affected by metastasis in various advanced cancers, including lung, breast, prostate, colorectal, and melanoma. Once a patient is diagnosed with bone metastasis, the patient's quality of life and overall survival are significantly reduced owing to a wide range of morbidities and the increasing difficulty of treatment. Many studies have shown that bone metastasis is closely related to bone microenvironment, especially bone immune microenvironment. However, the effects of various immune cells in the bone microenvironment on bone metastasis remain unclear. Here, we described the changes in various immune cells during bone metastasis and discussed their related mechanisms. Osteoblasts, adipocytes, and other non-immune cells closely related to bone metastasis were also included. This review also summarized the existing treatment methods and potential therapeutic targets, and provided insights for future studies of cancer bone metastasis.

The Predictive Value of Blood-Derived Exosomal miRNAs as Biomarkers in Breast Cancer: A Systematic Review

Breast cancer (BC) remains a widespread disease worldwide, despite advances in its detection and treatment. microRNAs (miRNAs) play a significant role in cancer, and their presence within exosomes may confer several advantages in terms of tumor initiation, propagation, immune evasion, and drug resistance compared to freely circulating miRNAs in the blood. The objective of this study was to conduct a systematic review to analyze the role of exosomal miRNAs present in serum or plasma as biomarkers in BC. Bibliographic sources were collected from various databases with no starting date limit until March 2023. The search terms used were related to "breast cancer," "microRNAs," and "exosomes." Following the search, inclusion and exclusion criteria were applied, resulting in a total of 46 articles. Data were extracted from the selected studies and summarized to indicate the miRNAs, type of dysregulation, sample source, number of patients and controls, and clinical relevance of the miRNAs. We carried out an enrichment study of the microRNAs that appeared in at least 3 studies, those that were suitable for selection were miR-16, miR-21 and miR-155. Exosomal miRNAs isolated from blood samples of patients diagnosed with BC could be valuable in the clinical setting. They could provide information about early diagnosis, disease progression, recurrence, treatment response, and metastases. It is crucial to reach a consensus on the specific exosomal miRNAs to detect and the most appropriate type of sample for comprehensive utilization of miRNAs as biomarkers for BC.

Targeting initial tumour-osteoclast spatiotemporal interaction to prevent bone metastasis

Bone is the most common site of metastasis, and although low proliferation and immunoediting at the early stage make existing treatment modalities less effective, the microenvironment-inducing behaviour could be a target for early intervention. Here we report on a spatiotemporal coupling interaction between tumour cells and osteoclasts, and named the tumour-associated osteoclast 'tumasteoclast'-a subtype of osteoclasts in bone metastases induced by tumour-migrasome-mediated cytoplasmic transfer. We subsequently propose an in situ decoupling-killing strategy in which tetracycline-modified nanoliposomes encapsulating sodium bicarbonate and sodium hydrogen phosphate are designed to specifically release high concentrations of hydrogen phosphate ions triggered by tumasteoclasts, which depletes calcium ions and forms calcium-phosphorus crystals. This can inhibit the formation of migrasomes for decoupling and disrupt cell membrane for killing, thereby achieving early prevention of bone metastasis. This study provides a research model for exploring tumour cell behaviour in detail and a proof-of-concept for behaviour-targeting strategy.

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.

Defining tropism and activity of natural and engineered extracellular vesicles

Extracellular vesicles (EVs) have important roles as mediators of cell-to-cell communication, with physiological functions demonstrated in various in vivo models. Despite advances in our understanding of the biological function of EVs and their potential for use as therapeutics, there are limitations to the clinical approaches for which EVs would be effective. A primary determinant of the biodistribution of EVs is the profile of proteins and other factors on the surface of EVs that define the tropism of EVs in vivo. For example, proteins displayed on the surface of EVs can vary in composition by cell source of the EVs and the microenvironment into which EVs are delivered. In addition, interactions between EVs and recipient cells that determine uptake and endosomal escape in recipient cells affect overall systemic biodistribution. In this review, we discuss the contribution of the EV donor cell and the role of the microenvironment in determining EV tropism and thereby determining the uptake and biological activity of EVs.

Macrophage heterogeneity in bone metastasis

Previous studies illustrated that macrophage, a type of innate immune cell, plays critical roles in tumour progression and metastasis. Bone is the most frequent site of metastasis for several cancer types including breast, prostate, and lung. In bone metastasis, osteoclast, a macrophage subset specialized in bone resorption, was heavily investigated in the past. Recent studies illustrated that other macrophage subsets, e.g. monocyte-derived macrophages, and bone resident macrophages, promoted bone metastasis independent of osteoclast function. These novel mechanisms further improved our understanding of macrophage heterogeneity in the context of bone metastasis and illustrated new opportunities for future studies.

Hierarchical False Discovery Rate Control for High-dimensional Survival Analysis with Interactions

With the development of data collection techniques, analysis with a survival response and high-dimensional covariates has become routine. Here we consider an interaction model, which includes a set of low-dimensional covariates, a set of high-dimensional covariates, and their interactions. This model has been motivated by gene-environment (G-E) interaction analysis, where the E variables have a low dimension, and the G variables have a high dimension. For such a model, there has been extensive research on estimation and variable selection. Comparatively, inference studies with a valid false discovery rate (FDR) control have been very limited. The existing high-dimensional inference tools cannot be directly applied to interaction models, as interactions and main effects are not "equal". In this article, for high-dimensional survival analysis with interactions, we model survival using the Accelerated Failure Time (AFT) model and adopt a "weighted least squares + debiased Lasso" approach for estimation and selection. A hierarchical FDR control approach is developed for inference and respect of the "main effects, interactions" hierarchy. The asymptotic distribution properties of the debiased Lasso estimators are rigorously established. Simulation demonstrates the satisfactory performance of the proposed approach, and the analysis of a breast cancer dataset further establishes its practical utility.

The enzymes of serine synthesis pathway in cancer metastasis

Metastasis, the major cause of cancer mortality, requires cancer cells to reprogram their metabolism to adapt to and thrive in different environments, thereby leaving metastatic cells metabolic characteristics different from their parental cells. Mounting research has revealed that the de novo serine synthesis pathway (SSP), a glycolytic branching pathway that consumes glucose carbons for serine makeup and α-ketoglutarate generation and thus supports the proliferation, survival, and motility of cancer cells, is one such reprogrammed metabolic pathway. During different metastatic cascades, the SSP enzyme proteins or their enzymatic activity are both dynamically altered; manipulating their expression or catalytic activity could effectively prevent the progression of cancer metastasis; and the SSP enzymatic proteins could even conduce to metastasis via their nonenzymatic functions. In this article we overview the SSP dynamics during cancer metastasis and put the focuses on the regulatory role of the SSP in metastasis and the underlying mechanisms that mainly involve cellular anabolism/catabolism, redox balance, and epigenetics, aiming to provide a theoretical basis for the development of therapeutic strategies for targeting metastatic lesions.

LSD1 modulates the bone metastasis of breast cancer cells through hnRNPA2B1-mediated sorting of exosomal miRNAs

Bone metastasis is a key contributor to morbidity and mortality of breast cancer patients. We have previously shown that exosomal miRNAs derived from LSD1 knockdown (KD) breast cancer cells inhibit osteoblast differentiation and promote osteoclast differentiation. However, how LSD1 regulates exosomal miRNAs and whether miRNAs promote bone metastasis through the formation of pre-metastatic niches remains unclear. In vivo experiments demonstrates that exosomes derived from LSD1 KD breast cancer cells significantly promoted bone metastasis. To explore the mechanism underlying the effect of LSD1 on exosomes in breast cancer cells, exosomal and cellular miRNAs from control, LSD1 KD, and rescue cells were sequenced. Interestingly, approximately 80% of LSD1-associated miRNAs were downregulated in exosomes from LSD1 KD cells. The consensus sequence UAGGGC, was identified in many miRNAs downregulated in LSD1 KD exosomes. We found that hnRNPA2B1 regulated the exosomal sorting of miR-6881-3p and some other miRNAs. LSD1 deficiency reduced hnRNPA2B1 expression in breast cancer cells by decreasing the level of H3K9me2 demethylation in the promoter region of the hnRNPA2B1 gene. Our study revealed that LSD1 plays a crucial role in the regulation of exosomal sorting of miRNA.

HTLV-1 infected T cells cause bone loss via small extracellular vesicles

Adult T cell leukemia (ATL), caused by infection with human T cell leukemia virus type 1 (HTLV-1), is often complicated by hypercalcemia and osteolytic lesions. Therefore, we studied the communication between patient-derived ATL cells (ATL-PDX) and HTLV-1 immortalized CD4+ T cell lines (HTLV/T) with osteoclasts and their effects on bone mass in mice. Intratibial inoculation of some HTLV/T lead to a profound local decrease in bone mass similar to marrow-replacing ATL-PDX, despite the fact that few HTLV/T cells persisted in the bone. To study the direct effect of HTLV/T and ATL-PDX on osteoclasts, supernatants were added to murine and human osteoclast precursors. ATL-PDX supernatants from hypercalcemic patients promoted formation of mature osteoclasts, while those from HTLV/T were variably stimulatory, but had largely consistent effects between human and murine cultures. Interestingly, this osteoclastic activity did not correlate with expression of osteoclastogenic cytokine RANKL, suggesting an alternative mechanism. HTLV/T and ATL-PDX produce small extracellular vesicles (sEV), known to facilitate HTLV-1 infection. We hypothesized that these sEV also mediate bone loss by targeting osteoclasts. We isolated sEV from both HTLV/T and ATL-PDX, and found they carried most of the activity found in supernatants. In contrast, sEV from uninfected activated T cells had little effect. Analysis of sEV (both active and inactive) by mass spectrometry and electron microscopy confirmed absence of RANKL and intact virus. Viral proteins Tax and Env were only present in sEV from the active, osteoclast-stimulatory group, along with increased representation of proteins involved in osteoclastogenesis and bone resorption. sEV injected over mouse calvaria in the presence of low dose RANKL caused more osteolysis than RANKL alone. Thus, HTLV-1 infection of T cells can cause release of sEV with strong osteolytic potential, providing a mechanism beyond RANKL production that modifies the bone microenvironment, even in the absence of overt leukemia.

Multiple influence of immune cells in the bone metastatic cancer microenvironment on tumors

Bone is a common organ for solid tumor metastasis. Malignant bone tumor becomes insensitive to systemic therapy after colonization, followed by poor prognosis and high relapse rate. Immune and bone cells in situ constitute a unique immune microenvironment, which plays a crucial role in the context of bone metastasis. This review firstly focuses on lymphatic cells in bone metastatic cancer, including their function in tumor dissemination, invasion, growth and possible cytotoxicity-induced eradication. Subsequently, we examine myeloid cells, namely macrophages, myeloid-derived suppressor cells, dendritic cells, and megakaryocytes, evaluating their interaction with cytotoxic T lymphocytes and contribution to bone metastasis. As important components of skeletal tissue, osteoclasts and osteoblasts derived from bone marrow stromal cells, engaging in 'vicious cycle' accelerate osteolytic bone metastasis. We also explain the concept tumor dormancy and investigate underlying role of immune microenvironment on it. Additionally, a thorough review of emerging treatments for bone metastatic malignancy in clinical research, especially immunotherapy, is presented, indicating current challenges and opportunities in research and development of bone metastasis therapies.

The Role of Breast Cancer Cells in Bone Metastasis: Suitable Seeds for Nourishing Soil

PURPOSE OF REVIEW

The purpose of this review was to describe the characteristics of breast cancer cells prone to developing bone metastasis and determine how they are regulated by the bone microenvironment.

RECENT FINDINGS

The bone is a site of frequent breast cancer metastasis. Bone metastasis accounts for 70% of advanced breast cancer cases and remains incurable. It can lead to skeletal-related events, such as bone fracture and pain, and seriously affect the quality of life of patients. Breast cancer cells escape from the primary lesion and spread to the bone marrow in the early stages. They can then enter the dormant state and restore tumourigenicity after several years to develop overt metastasis. In the last few years, an increasing number of studies have reported on the factors promoting bone metastasis of breast cancer cells, both at the primary and metastatic sites. Identifying factors associated with bone metastasis aids in the early recognition of bone metastasis tendency. How to target these factors and minimize the side effects on the bone remains to be further explored.

The miR-19a/Cylindromatosis Axis Regulates Pituitary Adenoma Bone Invasion by Promoting Osteoclast Differentiation

BACKGROUND

The presence of bone invasion in aggressive pituitary adenoma (PA) was found in our previous study, suggesting that PA cells may be involved in the process of osteoclastogenesis. miR-19a (as a key member of the miR-17-92 cluster) has been reported to activate the nuclear factor-кB (NF-кB) pathway and promote inflammation, which could be involved in the process of the bone invasion of pituitary adenoma.

METHODS

In this work, FISH was applied to detect miR-19a distribution in tissues from patients with PA. A model of bone invasion in PA was established, GH3 cells were transfected with miR-19a mimic, and the grade of osteoclastosis was detected by HE staining. qPCR was performed to determine the expression of miR-19a throughout the course of RANKL-induced osteoclastogenesis. After transfected with a miR-19a mimic, BMMs were treated with RANKL for the indicated time, and the osteoclast marker genes were detected by qPCR and Western Blot. Pit formation and F-actin ring assay were used to evaluate the function of osteoclast. The TargetScan database and GSEA were used to find the potential downstream of miR-19a, which was verified by Co-IP, Western Blot, and EMSA.

RESULTS

Here, we found that miR-19a expression levels were significantly correlated with the bone invasion of PA, both in clinical samples and animal models. The osteoclast formation prior to bone resorption was dramatically enhanced by miR-19, which was mediated by decreased cylindromatosis (CYLD) expression, increasing the K63 ubiquitination of tumor necrosis factor receptor-associated factor 6 (TRAF6). Consequently, miR-19a promotes osteoclastogenesis by the activation of the downstream NF-кB and mitogen-activated protein kinase (MAPK) pathways.

CONCLUSIONS

To summarize, the results of this study indicate that PA-derived miR-19a promotes osteoclastogenesis by inhibiting CYLD expression and enhancing the activation of the NF-кB and MAPK pathways.

Functional evaluation of dendritic cells and extracellular vesicles as immunotherapy for breast cancer

Dendritic cells (DCs) play critical roles in recognizing and presenting antigens to T cells. They secrete dendritic cell-derived extracellular vesicles (DC-sEVs), which could mimic the function of DCs. Therefore, we explore the possibility of using DC-sEVs as a potential personalized vaccine in this study. We compared the efficacy of DCs and DC-sEVs on stimulating the immune system to target breast cancer cells and found that DC-sEVs had significantly more MHC molecules on the surface when compared to the parental DCs. In our in vivo and in vitro testing, Dc-sEVs showed significant advantages over DCs, regarding efficacy, safety, storage, and potential delivery advantages. DC-sEVs were able to suppress the growth of immune-cold breast tumors, while DCs failed to do so. These results indicate the strong potential utility of DC-sEVs as a personalized immunotherapy for breast cancer.

Design of Nanodrug Delivery Systems for Tumor Bone Metastasis

Tumor metastasis is a complex process that is controlled at the molecular level by numerous cytokines. Primary breast and prostate tumors most commonly metastasize to bone, and the development of increasingly accurate targeted nanocarrier systems has become a research focus for more effective anti-bone metastasis therapy. This review summarizes the molecular mechanisms of bone metastasis and the principles and methods for designing bone-targeted nanocarriers and then provides an in-depth review of bone-targeted nanocarriers for the treatment of bone metastasis in the context of chemotherapy, photothermal therapy, gene therapy, and combination therapy. Furthermore, this review also discusses the treatment of metastatic and primary bone tumors, providing directions for the design of nanodelivery systems and future research.

Decoding the interaction between miR-19a and CBX7 focusing on the implications for tumor suppression in cancer therapy

Cancer is a complex and multifaceted disease characterized by uncontrolled cell growth, genetic alterations, and disruption of normal cellular processes, leading to the formation of malignant tumors with potentially devastating consequences for patients. Molecular research is important in the diagnosis and treatment, one of the molecular mechanisms involved in various cancers is the fluctuation of gene expression. Non-coding RNAs, especially microRNAs, are involved in different stages of cancer. MicroRNAs are small RNA molecules that are naturally produced within cells and bind to the 3'-UTR of target mRNA, repressing gene expression by regulating translation. Overexpression of miR-19a has been reported in human malignancies. Upregulation of miR-19a as a member of the miR-17-92 cluster is key to tumor formation, cell proliferation, survival, invasion, metastasis, and drug resistance. Furthermore. bioinformatics and in vitro data reveal that the miR-19a-3p isoform binds to the 3'UTR of CBX7 and was identified as the miR-19a-3p target gene. CBX7 is known as a tumor suppressor. This review initially describes the regulation of mir-19a in multiple cancers. Accordingly, the roles of miR-19 in affecting its target gene expression CBX7 in carcinoma also be discussed.

Predictive and prognostic biomarkers of bone metastasis in breast cancer: current status and future directions

The most common site of metastasis in breast cancer is the bone, where the balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation is disrupted. This imbalance causes osteolytic bone metastasis in breast cancer, which leads to bone pain, pathological fractures, spinal cord compression, and other skeletal-related events (SREs). These complications reduce patients' quality of life significantly and have a profound impact on prognosis. In this review, we begin by providing a brief overview of the epidemiology of bone metastasis in breast cancer, including current diagnostic tools, treatment approaches, and existing challenges. Then, we will introduce the pathophysiology of breast cancer bone metastasis (BCBM) and the animal models involved in the study of BCBM. We then come to the focus of this paper: a discussion of several biomarkers that have the potential to provide predictive and prognostic value in the context of BCBM-some of which may be particularly compatible with more comprehensive liquid biopsies. Beyond that, we briefly explore the potential of new technologies such as single-cell sequencing and organoid models, which will improve our understanding of tumor heterogeneity and aid in the development of improved biomarkers. The emerging biomarkers discussed hold promise for future clinical application, aiding in the prevention of BCBM, improving the prognosis of patients, and guiding the implementation of personalized medicine.

High expression of integrin-binding sialoprotein (IBSP) is associated with poor prognosis of osteosarcoma

INTRODUCTION

Osteosarcoma is a malignant tumor, accounting for 20% of primary malignant bone tumors worldwide. However, the role of IBSP as a biomarker in osteosarcoma progression has not been studied yet.

METHODS

85 cases of IBSP expression and clinical characteristics were obtained from TARGET database. Through the Kaplan-Meier curve, subgroup analysis, and univariate and multivariate Cox analysis, we further assessed the independent predictive capacity of IBSP expression for overall survival (OS) and relapse-free survival (RFS).

RESULTS

The mRNA expression of IBSP was higher in osteosarcoma than normal tissue (P < 0.0001). IBSP expression grouped by vital status showed statistical differences (P = 0.042). The race (P = 0.0183), vital status (P = 0.0034), and sample type (P = 0.0020) showed significant differences. IBSP expression exhibited satisfied diagnostic ability for osteosarcoma. The univariate and multivariate analysis confirmed that IBSP expression was an independent risk factor for OS (HR = 3.425, 95% CI: 1.604-7.313, P = 0.002) and RFS (HR = 3.377, 95% CI: 1.775-6.424, P < 0.001) in osteosarcoma patients. High IBSP expression was significantly associated with poor OS and RFS (P < 0.0001). The higher IBSP expression was observed in osteosarcoma (P < 0.001), confirmed by the IHC staining. The CCK-8 and colony formation assay showed that IBSP knockdown inhibits cell proliferation while overexpression promotes cell proliferation (P < 0.05).

CONCLUSION

High expression of IBSP was associated with poor OS and RFS. IBSP could serve as a potential biomarker for osteosarcoma, which could aid in early detection and disease monitoring.

The Emerging Roles of Exosomal miRNAs in Breast Cancer Progression and Potential Clinical Applications

Breast cancer remains the leading malignancy in terms of morbidity and mortality today. The tumor microenvironment of breast cancer includes multiple cell types, secreted proteins, and signaling components such as exosomes. Among these, exosomes have a lipid bilayer structure. Exosomes can reflect the biological traits of the parent cell and carry a variety of biologically active components, including proteins, lipids, small molecules, and non-coding RNAs, which include miRNA, lncRNA, and circRNA. MiRNAs are a group of non-coding RNAs of approximately 20-23 nucleotides in length encoded by the genome, triggering silencing and functional repression of target genes. MiRNAs have been shown to play a significant role in the development of cancer owing to their role in the prognosis, pathogenesis, diagnosis, and treatment of cancer. MiRNAs in exosomes can serve as effective mediators of information transfer from parental cells to recipient cells and trigger changes in biological traits such as proliferation, invasion, migration, and drug resistance. These changes can profoundly alter the progression of breast cancer. Therefore, here, we systematically summarize the association of exosomal miRNAs on breast cancer progression, diagnosis, and treatment in the hope of providing novel strategies and directions for subsequent breast cancer treatment.

Exosomal miR-222-3p contributes to castration-resistant prostate cancer by activating mTOR signaling

Despite the clinical benefits of androgen deprivation therapy, most patients with advanced androgen-dependent prostate cancer (ADPC) eventually relapse and progress to lethal androgen-independent prostate cancer (AIPC), also termed castration-resistant prostate cancer (CRPC). MiRNAs can be packaged into exosomes (Exos) and shuttled between cells. However, the roles and mechanisms of exosomal miRNAs involved in CRPC progression have not yet been fully elucidated. Here, we find that miR-222-3p is elevated in AIPC cells, which results in remarkable enhancement of cell proliferation, migration, and invasion ability. Furthermore, Exos released by AIPC cells can be uptaken by ADPC cells, thus acclimating ADPC cells to progressing to more aggressive cell types in vitro and in vivo through exosomal transfer of miR-222-3p. Mechanistically, Exos-miR-222-3p promoted ADPC cells transformed to AIPC-like cells, at least in part, by activating mTOR signaling through targeting MIDN. Our results show that AIPC cells secrete Exos containing miRNA cargo. These cargos can be transferred to ADPC cells through paracrine mechanisms that have a strong impact on cellular functional remodeling. The current work underscores the great therapeutic potential of targeting Exo miRNAs, either as a single agent or combined with androgen receptor pathway inhibitors for CRPC treatment.

Mechanisms of Organ-Specific Metastasis of Breast Cancer

Cancer metastasis, or the development of secondary tumors in distant tissues, accounts for the vast majority of fatalities in patients with breast cancer. Breast cancer cells show a striking proclivity to metastasize to distinct organs, specifically the lung, liver, bone, and brain, where they face unique environmental pressures and a wide variety of tissue-resident cells that together create a strong barrier for tumor survival and growth. As a consequence, successful metastatic colonization is critically dependent on reciprocal cross talk between cancer cells and host cells within the target organ, a relationship that shapes the formation of a tumor-supportive microenvironment. Here, we discuss the mechanisms governing organ-specific metastasis in breast cancer, focusing on the intricate interactions between metastatic cells and specific niche cells within a secondary organ, and the remarkable adaptations of both compartments that cooperatively support cancer growth. More broadly, we aim to provide a framework for the microenvironmental prerequisites within each distinct metastatic site for successful breast cancer metastatic seeding and outgrowth.

Exosomal long noncoding RNA MLETA1 promotes tumor progression and metastasis by regulating the miR-186-5p/EGFR and miR-497-5p/IGF1R axes in non-small cell lung cancer

BACKGROUND

Lung cancer is the most common and deadliest cancer worldwide, and approximately 90% of all lung cancer deaths are caused by tumor metastasis. Tumor-derived exosomes could potentially promote tumor metastasis through the delivery of metastasis-related molecules. However, the function and underlying mechanism of exosomal long noncoding RNA (lncRNA) in lung cancer metastasis remain largely unclear.

METHODS

Cell exosomes were purified from conditioned media by differential ultracentrifugation and observed using transmission electron microscopy, and the size distributions were determined by nanoparticle tracking analysis. Exosomal lncRNA sequencing (lncRNA-seq) was used to identify long noncoding RNAs. Cell migration and invasion were determined by wound-healing assays, two-chamber transwell invasion assays and cell mobility tracking. Mice orthotopically and subcutaneously xenografted with human cancer cells were used to evaluate tumor metastasis in vivo. Western blot, qRT‒PCR, RNA-seq, and dual-luciferase reporter assays were performed to investigate the potential mechanism. The level of exosomal lncRNA in plasma was examined by qRT‒PCR. MS2-tagged RNA affinity purification (MS2-TRAP) assays were performed to verify lncRNA-bound miRNAs.

RESULTS

Exosomes derived from highly metastatic lung cancer cells promoted the migration and invasion of lung cancer cells with low metastatic potential. Using lncRNA-seq, we found that a novel lncRNA, lnc-MLETA1, was upregulated in highly metastatic cells and their secreted exosomes. Overexpression of lnc-MLETA1 augmented cell migration and invasion of lung cancer. Conversely, knockdown of lnc-MLETA1 attenuated the motility and metastasis of lung cancer cells. Interestingly, exosome-transmitted lnc-MLETA1 promoted cell motility and metastasis of lung cancer. Reciprocally, targeting lnc-MLETA1 with an LNA suppressed exosome-induced lung cancer cell motility. Mechanistically, lnc-MLETA1 regulated the expression of EGFR and IGF1R by sponging miR-186-5p and miR-497-5p to facilitate cell motility. The clinical datasets revealed that lnc-MLETA1 is upregulated in tumor tissues and predicts survival in lung cancer patients. Importantly, the levels of exosomal lnc-MLETA1 in plasma were positively correlated with metastasis in lung cancer patients.

CONCLUSIONS

This study identifies lnc-MLETA1 as a critical exosomal lncRNA that mediates crosstalk in lung cancer cells to promote cancer metastasis and may serve as a prognostic biomarker and potential therapeutic target for lung cancer diagnosis and treatment.

Cellular and molecular characteristics of the premetastatic niches

The premetastatic niches (PMN) formed by primary tumor-derived molecules regulate distant organs and tissues to further favor tumor colonization. Targeted PMN therapy may prevent tumor metastasis in the early stages, which is becoming increasingly important. At present, there is a lack of in-depth understanding of the cellular and molecular characteristics of the PMN. Here, we summarize current research advances on the cellular and molecular characteristics of the PMN. We emphasize that PMN intervention is a potential therapeutic strategy for early prevention of tumor metastasis, which provides a promising basis for future research and clinical application.

Artificial intelligence-based radiomics in bone tumors: Technical advances and clinical application

Radiomics is the extraction of predefined mathematic features from medical images for predicting variables of clinical interest. Recent research has demonstrated that radiomics can be processed by artificial intelligence algorithms to reveal complex patterns and trends for diagnosis, and prediction of prognosis and response to treatment modalities in various types of cancer. Artificial intelligence tools can utilize radiological images to solve next-generation issues in clinical decision making. Bone tumors can be classified as primary and secondary (metastatic) tumors. Osteosarcoma, Ewing sarcoma, and chondrosarcoma are the dominating primary tumors of bone. The development of bone tumor model systems and relevant research, and the assessment of novel treatment methods are ongoing to improve clinical outcomes, notably for patients with metastases. Artificial intelligence and radiomics have been utilized in almost full spectrum of clinical care of bone tumors. Radiomics models have achieved excellent performance in the diagnosis and grading of bone tumors. Furthermore, the models enable to predict overall survival, metastases, and recurrence. Radiomics features have exhibited promise in assisting therapeutic planning and evaluation, especially neoadjuvant chemotherapy. This review provides an overview of the evolution and opportunities for artificial intelligence in imaging, with a focus on hand-crafted features and deep learning-based radiomics approaches. We summarize the current application of artificial intelligence-based radiomics both in primary and metastatic bone tumors, and discuss the limitations and future opportunities of artificial intelligence-based radiomics in this field. In the era of personalized medicine, our in-depth understanding of emerging artificial intelligence-based radiomics approaches will bring innovative solutions to bone tumors and achieve clinical application.

The role of non-coding RNAs in extracellular vesicles in breast cancer and their diagnostic implications

Breast Cancer (BC) is the most common form of cancer worldwide, responsible for 25% of cancers in women. Whilst treatment is effective and often curative in early BC, metastatic disease is incurable, highlighting the need for early detection. Currently, early detection relies on invasive procedures, however recent studies have shown extracellular vesicles (EVs) obtained from liquid biopsies may have clinical utility. EVs transport diverse bioactive cargos throughout the body, play major roles in intercellular communication and, importantly, mirror their cell of origin. In cancer cells, EVs alter the behaviour of the tumour microenvironment (TME), forming a bridge of communication between cancerous and non-cancerous cells to alter all aspects of cancer progression, including the formation of a pre-metastatic niche. Through gene regulatory frameworks, non-coding RNAs (ncRNAs) modulate vital molecular and cellular processes and can act as both tumour suppressors and oncogenic drivers in various cancer types. EVs transport and protect ncRNAs, facilitating their use clinically as liquid biopsies for early BC detection. This review summarises current research surrounding ncRNAs and EVs within BC, focusing on their roles in cancer progression through bi-directional communication with the microenvironment and their diagnostic implications. The role of EV ncRNAs in breast cancer. A representation of the different EV ncRNAs involved in tumourigenic processes in breast cancer. Pro-tumourigenic ncRNAs displayed in green and ncRNAs which inhibit oncogenic processes are shown in red.

RNA-binding protein CPSF6 regulates IBSP to affect pyroptosis in gastric cancer

BACKGROUND

Extensive evidence has illustrated the promotive role of integrin binding sialoprotein (IBSP) in the progression of multiple cancers. However, little is known about the functions of IBSP in gastric cancer (GC) progression.

AIM

To investigate the mechanism underlying the regulatory effects of IBSP in GC progression, and the relationship between IBSP and cleavage and polyadenylation factor 6 (CPSF6) in this process.

METHODS

The mRNA and protein expression of relevant genes were assessed through real-time quantitative polymerase chain reaction and Western blot, respectively. Cell viability was evaluated by Cell Counting Kit-8 assay. Cell invasion and migration were evaluated by Transwell assay. Pyroptosis was measured by flow cytometry. The binding between CPSF6 and IBSP was confirmed by luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

IBSP exhibited higher expression in GC tissues and cell lines than in normal tissues and cell lines. IBSP knockdown suppressed cell proliferation, migration, and invasion but facilitated pyroptosis. In the exploration of the regulatory mechanism of IBSP, potential RNA binding proteins for IBSP were screened with catRAPID omics v2.0. The RNA-binding protein CPSF6 was selected due to its higher expression in stomach adenocarcinoma. Luciferase reporter and RIP assays revealed that CPSF6 binds to the 3'-untranslated region of IBSP and regulates its expression. Knockdown of CPSF6 inhibited cell proliferation, migration, and invasion but boosted pyroptosis. Through rescue assays, it was uncovered that the retarded GC progression mediated by CPSF6 knockdown was reversed by IBSP overexpression.

CONCLUSION

Our study highlighted the vital role of the CPSF6/IBSP axis in GC, suggesting that IBSP might be an effective bio-target for GC treatment.

In Situ Capturing and Counting Device for the Specific Depletion and Purification of Cancer-Derived Exosomes

From metabolic waste to biological mediators, exosomes have emerged as the key player in a variety of pathological processes, particularly in oncogenesis. The exosome-mediated communication network involves nearly every step of cancer progression, promoting the proliferation and immune escape of cancer cells. Therefore, the removal of cancer-derived exosomes has profound clinical significance. Current methods for exosome separation and enrichment are either for large-scale samples or require complex pretreatment processes, lacking effective methods for trace-volume exosome capture in situ. Herein, we have developed an in situ exosome capturing and counting device based on the antibody-functionalized capillary. Specific antibodies targeting exosome biomarkers were immobilized to the inner wall of the capillary via biotin-streptavidin interaction for direct cancer exosome capturing. Subsequent exosome staining enabled imaging and enumeration. Acceptable linearity and reproducibility were achieved with our device, with the capturing and detective range between 3.3 × 104 and 3.3 × 108 particles, surpassing the nanoparticle tracking analysis by 2 orders of magnitude while requiring merely 30 μL sample. We demonstrated that MCF-7-derived exosomes induced epithelial-mesenchymal transition of epithelial cells MCF-10A, and our method was able to completely or partially reverse the transition by complete depletion or specific depletion of cancer exosomes without any preprocessing. Moreover, both whole exosomes and cancer-specific exosomes alone from mimic blood samples were successfully captured and counted, without obvious non-specific adsorption. In all, our approach realized the in situ depletion and number-counting of cancer-derived exosomes directly from the complex humoral environment, having the potential to provide a comprehensive tumor therapeutic and prognosis evaluation tool by targeted hemodialysis and counting of tumor-derived exosomes.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

Extracellular vesicle-mediated interorgan communication in metabolic diseases

The body partially maintains metabolic homeostasis through interorgan communication between metabolic organs under physiological conditions. This crosstalk is known to be mediated by hormones or metabolites, and has recently been expanding to include extracellular vesicles (EVs). EVs participate in interorgan communication under physiological and pathological conditions by encapsulating various bioactive cargoes, including proteins, metabolites, and nucleic acids. In this review we summarize the latest findings about the metabolic regulation of EV biogenesis, secretion, and components, and highlight the biological role of EV cargoes in interorgan communication in cancer, obesity, diabetes, and cardiovascular disease. We also discuss the potential application of EVs as diagnostic markers, and corresponding therapeutic strategies by EV engineering for both early detection and treatment of metabolic disorders.

Extracellular vesicles and particles as mediators of long-range communication in cancer: connecting biological function to clinical applications

Over the past decade, extracellular vesicles and particles (EVPs) have emerged as critical mediators of intercellular communication, participating in numerous physiological and pathological processes. In the context of cancer, EVPs exert local effects, such as increased invasiveness, motility, and reprogramming of tumor stroma, as well as systemic effects, including pre-metastatic niche formation, determining organotropism, promoting metastasis and altering the homeostasis of various organs and systems, such as the liver, muscle, and circulatory system. This review provides an overview of the critical advances in EVP research during the past decade, highlighting the heterogeneity of EVPs, their roles in intercellular communication, cancer progression, and metastasis. Moreover, the clinical potential of systemic EVPs as useful cancer biomarkers and therapeutic agents is explored. Last but not least, the progress in EVP analysis technologies that have facilitated these discoveries is discussed, which may further propel EVP research in the future.

Deciphering the Functional Status of Breast Cancers through the Analysis of Their Extracellular Vesicles

Breast cancer (BC) accounts for the highest incidence of tumor-related mortality among women worldwide, justifying the growing search for molecular tools for the early diagnosis and follow-up of BC patients under treatment. Circulating extracellular vesicles (EVs) are membranous nanocompartments produced by all human cells, including tumor cells. Since minimally invasive methods collect EVs, which represent reservoirs of signals for cell communication, these particles have attracted the interest of many researchers aiming to improve BC screening and treatment. Here, we analyzed the cargoes of BC-derived EVs, both proteins and nucleic acids, which yielded a comprehensive list of potential markers divided into four distinct categories, namely, (i) modulation of aggressiveness and growth; (ii) preparation of the pre-metastatic niche; (iii) epithelial-to-mesenchymal transition; and (iv) drug resistance phenotype, further classified according to their specificity and sensitivity as vesicular BC biomarkers. We discuss the therapeutic potential of and barriers to the clinical implementation of EV-based tests, including the heterogeneity of EVs and the available technologies for analyzing their content, to present a consistent, reproducible, and affordable set of markers for further evaluation.

CircRNA/lncRNA-miRNA-mRNA network and gene landscape in calcific aortic valve disease

BACKGROUND

Calcific aortic valve disease (CAVD) is a common valve disease with an increasing incidence, but no effective drugs as of yet. With the development of sequencing technology, non-coding RNAs have been found to play roles in many diseases as well as CAVD, but no circRNA/lncRNA-miRNA-mRNA interaction axis has been established. Moreover, valve interstitial cells (VICs) and valvular endothelial cells (VECs) play important roles in CAVD, and CAVD differed between leaflet phenotypes and genders. This work aims to explore the mechanism of circRNA/lncRNA-miRNA-mRNA network in CAVD, and perform subgroup analysis on the important characteristics of CAVD, such as key cells, leaflet phenotypes and genders.

RESULTS

We identified 158 differentially expressed circRNAs (DEcircRNAs), 397 DElncRNAs, 45 DEmiRNAs and 167 DEmRNAs, and constructed a hsa-circ-0073813/hsa-circ-0027587-hsa-miR-525-5p-SPP1/HMOX1/CD28 network in CAVD after qRT-PCR verification. Additionally, 17 differentially expressed genes (DEGs) in VICs, 9 DEGs in VECs, 7 DEGs between different leaflet phenotypes and 24 DEGs between different genders were identified. Enrichment analysis suggested the potentially important pathways in inflammation and fibro-calcification during the pathogenesis of CAVD, and immune cell patterns in CAVD suggest that M0 macrophages and memory B cells memory were significantly increased, and many genes in immune cells were also differently expressed.

CONCLUSIONS

The circRNA/lncRNA-miRNA-mRNA interaction axis constructed in this work and the DEGs identified between different characteristics of CAVD provide a direction for a deeper understanding of CAVD and provide possible diagnostic markers and treatment targets for CAVD in the future.

Single-cell sequencing analysis reveals the relationship between tumor microenvironment cells and oxidative stress in breast cancer bone metastases

Bone metastasis (BM) is one of the main manifestations of advanced breast cancer (BC), causing complications such as pathological fractures, which seriously affects the quality of life of patients and even leads to death. In our study, a global single-cell landscape of the tumor microenvironment was constructed using single cell RNA sequencing data from BM. BC cells were found to be reduced in the BM, while mesenchymal stem cells (MSCs), Fibroblasts and other cells were significantly more abundant in the BM. The subpopulations of these cells were further identified, and the pathways, developmental trajectories and transcriptional regulation of different subpopulations were discussed. The results suggest that with the development of BM, BC cells were vulnerable to oxidative damage, showing a high level of oxidative stress, which played a key role in cell apoptosis. Fibroblasts were obviously involved in the biological processes (BPs) related to ossification and bone remodeling, and play an important role in tumor cell inoculation to bone marrow and growth. MSC subpopulations were significantly enriched in a number of BPs associated with bone growth and development and oxidative stress and may serve as key components of BC cells homing and adhesion to the ecological niche of BM. In conclusion, our research results describe the appearance of tumor microenvironment cell subpopulations in breast cancer patients, reveal the important role of some cells in the balance of BM bone remodeling and the imbalance of BM development, and provide potential therapeutic targets for BM.

Extracellular vesicles in the treatment and diagnosis of breast cancer: a status update

Breast cancer is one of the leading causes of cancer-related death in women. Currently, the treatment of breast cancer is limited by the lack of effectively targeted therapy and patients often suffer from higher severity, metastasis, and resistance. Extracellular vesicles (EVs) consist of lipid bilayers that encapsulate a complex cargo, including proteins, nucleic acids, and metabolites. These bioactive cargoes have been found to play crucial roles in breast cancer initiation and progression. Moreover, EV cargoes play pivotal roles in converting mammary cells to carcinogenic cells and metastatic foci by extensively inducing proliferation, angiogenesis, pre-metastatic niche formation, migration, and chemoresistance. The present update review mainly discusses EVs cargoes released from breast cancer cells and tumor-derived EVs in the breast cancer microenvironment, focusing on proliferation, metastasis, chemoresistance, and their clinical potential as effective biomarkers.

Pan-cancer analysis shows that IBSP is a potential prognostic and immunotherapeutic biomarker for multiple cancer types including osteosarcoma

Background

IBSP is a member of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family that plays a vital role in bone formation, renewal and repair. Emerging evidence revealed that IBSP participated in the tumorigenesis and progression in some cancers. However, its significance in tumour prognosis and immunotherapy is still unknown.

Methods

In the current study, we studied the role of IBSP in tumorigenesis, tumor diagnosis, genomic heterogeneity, methylation modifications, immune infiltration, and therapy response in pan-cancer. In addition, we constructed a risk score model to assessed the prognostic classification efficiency of IBSP using the co-expression genes of IBSP in osteosarcoma (OS), and analyzed the expression and role of IBSP in OS through a series of assays in vitro.

Results

IBSP was upregulated in various cancers compared to the paired normal tissues, and it was strongly correlated with the prognosis, pathological stage, diagnostic accuracy, genomic heterogeneity, methylation modification, immune infiltration, immune and checkpoint. Moreover, the predictive model we established in combination with the clinical characteristics of OS patients showed high survival predictive power in these individuals. The assays in vitro showed that IBSP promoted the proliferation, migration and invasion of OS cells, which further confirmed IBSP's role in cancers.

Conclusions

Our research revealed the multifunctionality of IBSP in the tumorigenesis, progression and therapy in various cancers, which demonstrated that IBSP may serve as a potential prognostic biomarker and a novel immunotherapy target in pan-cancer.

Potential biomarkers for the early detection of bone metastases

The clinical manifestations of bone metastases are diversified while many sites remain asymptomatic at early stage. As the early diagnosis method is not perfect and the early symptoms of tumor bone metastasis are not typical, bone metastasis is not easy to be detected. Therefore, the search for bone metastasis-related markers is effective for timely detection of tumor bone metastases and the development of drugs to inhibit bone metastases. As a result, bone metastases can only be diagnosed when symptoms are found, increasing the risk of developing skeletal-related event (SREs), which significantly impairs the patient's quality of life. Therefore, the early diagnosis of bone metastases is of great importance for the treatment and prognosis of cancer patients. Changes of bone metabolism indexes appear earlier in bone metastases, but the traditional biochemical indexes of bone metabolism lack of specificity and could be interfered by many factors, which limits their application in the study of bone metastases. Some new biomarkers of bone metastases have good diagnostic value, such as proteins, ncRNAs, circulating tumor cells (CTCs). Therefore, this study mainly reviewed the initial diagnostic biomarkers of bone metastases which were expected to provide references for the early detection of bone metastases.

Circulating and extracellular vesicle-derived microRNAs as biomarkers in bone-related diseases

MicroRNAs (miRNA) are small non-coding RNA molecules that regulate posttranscriptional gene expression by repressing messengerRNA-targets. MiRNAs are abundant in many cell types and are secreted into extracellular fluids, protected from degradation by packaging in extracellular vesicles. These circulating miRNAs are easily accessible, disease-specific and sensitive to small changes, which makes them ideal biomarkers for diagnostic, prognostic, predictive or monitoring purposes. Specific miRNA signatures can be reflective of disease status and development or indicators of poor treatment response. This is especially important in malignant diseases, as the ease of accessibility of circulating miRNAs circumvents the need for invasive tissue biopsy. In osteogenesis, miRNAs can act either osteo-enhancing or osteo-repressing by targeting key transcription factors and signaling pathways. This review highlights the role of circulating and extracellular vesicle-derived miRNAs as biomarkers in bone-related diseases, with a specific focus on osteoporosis and osteosarcoma. To this end, a comprehensive literature search has been performed. The first part of the review discusses the history and biology of miRNAs, followed by a description of different types of biomarkers and an update of the current knowledge of miRNAs as biomarkers in bone related diseases. Finally, limitations of miRNAs biomarker research and future perspectives will be presented.

miRNAs as potential game-changers in bone diseases: Future medicinal and clinical uses

MicroRNAs (miRNAs), short, highly conserved non-coding RNA, influence gene expression by sequential mechanisms such as mRNA breakdown or translational repression. Many biological processes depend on these regulating substances, thus changes in their expression have an impact on the maintenance of cellular homeostasis and result in the emergence of a variety of diseases. Relevant studies have shown in recent years that miRNAs are involved in many stages of bone development and growth. Additionally, abnormal production of miRNA in bone tissues has been closely associated with the development of numerous bone disorders, such as osteonecrosis, bone cancer, and bone metastases. Many pathological processes, including bone loss, metastasis, the proliferation of osteosarcoma cells, and differentiation of osteoblasts and osteoclasts, are under the control of miRNAs. By bringing together the most up-to-date information on the clinical relevance of miRNAs in such diseases, this study hopes to further the study of the biological features of miRNAs in bone disorders and explore their potential as a therapeutic target.

Secreted microRNAs in bone metastasis

Bone metastasis is a common complication in several solid cancers, including breast, prostate, and lung. In the bone microenvironment, metastatic cancer cells disturb bone homeostasis leading to osteolytic or osteosclerotic lesions. Osteolytic lesions are characterized by an increased osteoclast-mediated bone resorption while osteosclerotic lesions are caused by enhanced activity of osteoblasts and formation of poor-quality bone. A common feature in bone metastasis is the complex interplay between the cancer cells and the cells of the bone microenvironment, which can occur already before the cancer cells enter the distant site. Cancer cells at the primary site can secrete soluble factors and extracellular vesicles to bone to create a "pre-metastatic niche" i.e., prime the microenvironment permissive for cancer cell homing, survival, and growth. Once in the bone, cancer cells secrete factors to activate the osteoclasts or osteoblasts and the so called "vicious cycle of bone metastases". These pathological cell-cell interactions are largely dependent on secreted proteins. However, increasing evidence demonstrates that secreted RNA molecules, in particular small non-coding microRNAs are critical mediators of the crosstalk between bone and cancer cells. This review article discusses the role of secreted miRNAs in bone metastasis development and progression, and their potential as non-invasive biomarkers.

Extracellular vesicles secreted from bone metastatic renal cell carcinoma promote angiogenesis and endothelial gap formation in bone marrow in a time-dependent manner in a preclinical mouse model

Introduction

Bone is a major metastatic site of renal cell carcinoma (RCC). Recently, it is well recognized that bone metastatic tumor cells remodel bone marrow vasculature. However, the precise mechanism underlying cell-cell communication between bone metastatic RCC and the cells in bone marrow remains unknown. Extracellular vesicles (EVs) reportedly play crucial roles in intercellular communication between metastatic tumor cells and bone marrow. Therefore, we conducted the current study to clarify the histological alteration in vascular endothelium in bone marrow induced by EVs secreted from bone metastatic RCC cells as well as association between angiogenesis in bone marrow and bone metastasis formation.

Materials and methods

We established a bone metastatic RCC cell line (786-O BM) by in vivo selection and observed phenotypic changes in tissues when EVs were intravenously injected into immunodeficient mice. Proteomic analysis was performed to identify the protein cargo of EVs that could contribute to histological changes in bone. Tissue exudative EVs (Te-EVs) from cancer tissues of patients with bone metastatic RCC (BM-EV) and those with locally advanced disease (LA-EV) were compared for in vitro function and protein cargo.

Results

Treatment of mice with EVs from 786-O BM promoted angiogenesis in the bone marrow in a time-dependent manner and increased the gaps of capillary endothelium. 786-O BM EVs also promoted tube formation in vitro. Proteomic analysis of EVs identified aminopeptidase N (APN) as a candidate protein that enhances angiogenesis. APN knockdown in 786-O BM resulted in reduced angiogenesis in vitro and in vivo. When parental 786-O cells were intracardially injected 12 weeks after treatment with786-O BM EVs, more bone metastasis developed compared to those treated with EVs from parental 786-O cells. In patient samples, BM-EVs contained higher APN compared to LA-EV. In addition, BM-EVs promoted tube formation in vitro compared to LA-EVs.

Conclusion

EVs from bone metastatic RCC promote angiogenesis and gap formation in capillary endothelium in bone marrow in a time-dependent manner.

The tumor-immune ecosystem in shaping metastasis

A better understanding of the mechanisms regulating cancer metastasis is critical to develop new therapies and decrease mortality. Emerging evidence suggests that the interactions between tumor cells and the host immune system play important roles in establishing metastasis. Tumor cells are able to recruit immune cells, which in turn promotes tumor cell invasion, intravasation, survival in circulation, extravasation, and colonization in different organs. The tumor-host immunological interactions also generate a premetastatic niche in distant organs which facilitates metastasis. In this review, we summarize the recent findings on how tumor cells and immune cells regulate each other to coevolve and promote the formation of metastases at the major organ sites of metastasis.

Propofol mediates bone metastasis by regulating PC-derived exosomal miR-142-3p

In this study we investigated the role of propofol in mediating prostate cancer (PCa) bone metastasis through regulating exosomal factors derived from PCa. We isolated exosomes from PCa cells and co-cultured them with mesenchymal stem cells (MSCs). PCa-derived exosomes increased calcium deposition of MSCs and upregulated ALPL'Alkaline phosphatase, tissue-nonspecific isozyme) and BGLAP (Bone Gamma-Carboxyglutamate Protein) expression. Propofol treatment reduced alkaline phosphatase (ALP) activity, and ALPL and BGLAP expression that was induced by PCa-derived exosomes in MSCs. miRNAs present in cancer cell-derived exosomes increased osteogenesis in these cells. We evaluated miRNA expression in PCa cells after treatment with propofol, and found that miR-142-3p was upregulated in PCa cells. Furthermore, we transfected MSCs with miR-142-3p mimics or inhibitors and revealed that miR-142-3p mimics reduced calcium deposition and downregulated ALP activity, and ALPL and BGLAP levels, while miR-142-3p inhibitors increased calcium deposition and increased ALP activity, and ALPL and BGLAP levels. Finally, we determined that MSCs co-cultured with PCa-derived exosomes and transfected with miR-142-3p mimic exhibited reduced calcium deposition and lower ALP activity, and expression of ALPL and BGLAP. These data demonstrate that propofol inhibits osteogenic differentiation and mineralization of MSCs induced by PCa-derived exosomes by regulation of miR-142-3p levels.

Potential miRNA Use as a Biomarker: From Breast Cancer Diagnosis to Metastasis

Breast cancer is the most common cancer in women. Despite advances in diagnosis and prognosis, distal metastases occur in these patients in up to 15% of cases within 3 years of diagnosis. The main organs in which BC metastasises are the bones, lungs, liver, and brain. Unfortunately, 90% of metastatic patients will die, making this an incurable disease. Researchers are therefore seeking biomarkers for diagnosis and metastasis in different organs. Optimally, such biomarkers should be easy to detect using, preferably, non-invasive methods, such as using miRNA molecules, which are small molecules of about 22 nt that have as their main function the post-transcriptional regulation of genes. Furthermore, due to their uncomplicated detection and reproducibility in the laboratory, they are a tool of complementary interest for diagnosis, prognosis, and treatment. With this in mind, in this review, we focus on describing the most current studies that propose using miRNA independently as a potential biomarker for the diagnosis and prediction of brain, lung, liver, and bone metastases, as well as to open a window of opportunity to deepen this area of study to eventually use miRNAs molecules in clinical practice for the benefit of BC patients.

MiRNAs and snoRNAs in Bone Metastasis: Functional Roles and Clinical Potential

Bone is a frequent site of metastasis. Bone metastasis is associated with a short-term prognosis in cancer patients, and current treatments aim to slow its growth, but are rarely curative. Thus, revealing molecular mechanisms that explain why metastatic cells are attracted to the bone micro-environment, and how they successfully settle in the bone marrow-taking advantage over bone resident cells-and grow into macro-metastasis, is essential to propose new therapeutic approaches. MicroRNAs and snoRNAs are two classes of small non-coding RNAs that post-transcriptionally regulate gene expression. Recently, microRNAs and snoRNAs have been pointed out as important players in bone metastasis by (i) preparing the pre-metastatic niche, directly and indirectly affecting the activities of osteoclasts and osteoblasts, (ii) promoting metastatic properties within cancer cells, and (iii) acting as mediators within cells to support cancer cell growth in bone. This review aims to highlight the importance of microRNAs and snoRNAs in metastasis, specifically in bone, and how their roles can be linked together. We then discuss how microRNAs and snoRNAs are secreted by cancer cells and be found as extracellular vesicle cargo. Finally, we provide evidence of how microRNAs and snoRNAs can be potential therapeutic targets, at least in pre-clinical settings, and how their detection in liquid biopsies can be a useful diagnostic and/or prognostic biomarker to predict the risk of relapse in cancer patients.

Exosomal miR-1304-3p promotes breast cancer progression in African Americans by activating cancer-associated adipocytes

Breast cancer displays disparities in mortality between African Americans and Caucasian Americans. However, the exact molecular mechanisms remain elusive. Here, we identify miR-1304-3p as the most upregulated microRNA in African American patients. Importantly, its expression significantly correlates with poor progression-free survival in African American patients. Ectopic expression of miR-1304 promotes tumor progression in vivo. Exosomal miR-1304-3p activates cancer-associated adipocytes that release lipids and enhance cancer cell growth. Moreover, we identify the anti-adipogenic gene GATA2 as the target of miR-1304-3p. Notably, a single nucleotide polymorphism (SNP) located in the miR-1304 stem-loop region shows a significant difference in frequencies of the G allele between African and Caucasian American groups, which promotes the maturation of miR-1304-3p. Therefore, our results reveal a mechanism of the disparity in breast cancer progression and suggest a potential utility of miR-1304-3p and the associated SNP as biomarkers for predicting the outcome of African American patients.