Restoring Tissue Homeostasis at Metastatic Sites: A Focus on Extracellular Vesicles in Bone Metastasis

Tissue-derived extracellular vesicles in cancer progression: mechanisms, roles, and potential applications

Extracellular vesicles (EVs) are small lipid bilayer-enclosed vesicles that mediate vital cellular communication by transferring cargo between cells. Among these, tissue-derived extracellular vesicles (Ti-EVs) stand out due to their origin from the tissue microenvironment, providing a more accurate reflection of changes in this setting. This unique advantage makes Ti-EVs valuable in investigating the intricate relationship between extracellular vesicles and cancer progression. Despite considerable research efforts exploring the association between Ti-EVs and cancers, a comprehensive clustering or grouping of these studies remains lacking. In this review, we aim to fill this gap by presenting a comprehensive synthesis of the mechanisms underlying Ti-EV generation, release, and transport within cancer tissues. Moreover, we delve into the pivotal roles that Ti-EVs play in cancer progression, shedding light on their potential as diagnostic and therapeutic tools. The review culminates in the construction of a comprehensive functional spectrum of Ti-EVs, providing a valuable reference for future research endeavors. By summarizing the current state of knowledge on Ti-EVs and their significance in tumor biology, this work contributes to a deeper understanding of cancer microenvironment dynamics and opens up avenues for harnessing Ti-EVs in diagnostic and therapeutic applications.

Investigating the Differential Circulating microRNA Expression in Adolescent Females with Severe Idiopathic Scoliosis: A Proof-of-Concept Observational Clinical Study

Adolescent Idiopathic Scoliosis (AIS) is the most common form of three-dimensional spinal disorder in adolescents between the ages of 10 and 18 years of age, most commonly diagnosed in young women when severe disease occurs. Patients with AIS are characterized by abnormal skeletal growth and reduced bone mineral density. The etiology of AIS is thought to be multifactorial, involving both environmental and genetic factors, but to date, it is still unknown. Therefore, it is crucial to further investigate the molecular pathogenesis of AIS and to identify biomarkers useful for predicting curve progression. In this perspective, the relative abundance of a panel of microRNAs (miRNAs) was analyzed in the plasma of 20 AIS patients and 10 healthy controls (HC). The data revealed a significant group of circulating miRNAs dysregulated in AIS patients compared to HC. Further bioinformatic analyses evidenced a more restricted expression of some miRNAs exclusively in severe AIS females. These include some members of the miR-30 family, which are considered promising regulators for treating bone diseases. We demonstrated circulating extracellular vesicles (EVs) from severe AIS females contained miR-30 family members and decreased the osteogenic differentiation of mesenchymal stem cells. Proteomic analysis of EVs highlighted the expression of proteins associated with orthopedic disease. This study provides preliminary evidence of a miRNAs signature potentially associated with severe female AIS and suggests the corresponding vesicular component may affect cellular mechanisms crucial in AIS, opening the scenario for in-depth studies on prognostic differences related to gender and grade.

Signal transduction pathways alter the molecular cargo of extracellular vesicles: implications in regenerative medicine

Extracellular vesicles (EVs) possess regenerative properties and are also considered as future vaccines. All types of cells secrete EVs; however, the amount of EVs secreted by the cells varies under various physiological as well as pathological states. Several articles have reviewed the molecular composition and potential therapeutic applications of EVs. Likewise, the 'sorting signals' associated with specific macromolecules have also been identified, but how the signal transduction pathways prevailing in the parent cells alter the molecular profile of the EVs or the payload they carry has not been sufficiently reviewed. Here, we have specifically discussed the implications of these alterations in the macromolecular cargo of EVs for their therapeutic applications in regenerative medicine.

Role of exosomes in prostate cancer bone metastasis

Bone is a preferred metastatic site of prostate cancer (PCa), and most patients with PCa metastases develop osteogenic bone metastasis, which manifests as disturbed bone structure and poor bone quality. However, the underlying mechanisms of PCa bone metastasis remain unclear. In recent years, increasing evidence has implicated extracellular vesicles, especially exosomes, in PCa bone metastasis. Exosomes are 30-150 nm in diameter, enclosing a cargo of biomolecules, such as DNA, RNA, and proteins. Exosomes play a functional role in intercellular communication, modulate the functions of recipient cells, and potentially modulate bone microenvironment changes, thereby influencing the development of PCa bone metastasis. This review summarizes the involvement of exosomes in the imbalance between bone resorption and formation, and establishing a pre-metastatic niche in bone marrow, as well as potential clinical applications of exosomes in therapeutic strategies for treating patients with advanced PCa with bone metastasis.

Pathological tissue formation and degradation biomarkers correlate with patient reported pain outcomes: an explorative study

Background

The lack of disease modifying drugs in Osteoarthritis (OA) may be attributed to the difficulty in robust response based on patient-reported outcomes (PROs) linked to drug mechanism of action. Joint tissue turnover biomarkers are associated with disease progression. A subset of patients has elevated serum levels of CRP metabolite (CRPM). This explorative study investigates the associations between PROs and joint tissue turnover markers in patients with high or low CRPM.

Methods

Serum of 146 knee OA patients of the New York Inflammation cohort and 21 healthy donors were assessed for biomarkers of collagen degradation (C1M, C2M, C3M, C4M), formation (PRO-C1, PRO-C2, PRO-C3, PRO-C4), and CRPM. Mean (SD) age was 62.5 (10.1); BMI, 26.6 (3.6); 62% women; and, 67.6% had symptomatic OA. WOMAC pain, stiffness, function, and total were recorded at baseline and at two-year follow-up. Associations were adjusted for race, sex, age, BMI, and NSAID.

Results

There was no difference in markers between donors and patients. C2M correlated with the WOMAC scores in all CRPM groups. Significant correlations were observed between PROs and PRO-C4, C1M, and C3M in the CRPMhigh group. The best predictive models for improvement were found for function and total with AUCs of 0.74 (p ​< ​0.01) and 0.78 (p ​< ​0.01). The best predictive models for worsening were found for function and total with AUCs of 0.84 (p ​< ​0.01) and 0.80 (p ​< ​0.05).

Conclusion

We hypothesize that collagen markers are prognostic tools for segregating patient populations in clinical trials.

Methodologies to evaluate the radiation-induced changes on extracellular vesicles

The extracellular vesicles (EVs) are carriers that actively transfer functional biomolecules between cells affecting the intercellular communication (Pitt, Kroemer, & Zitvogel, 2016). EV signaling has consequences on the targeted cell behavior impacting multiple processes from health to disease, including cancer (Yates et al., 2022). Radiation treatment (RT) is one of the gold standard and effective treatments for cancer, as curative or palliative (Chandra, Keane, Voncken, & Thomas, 2021). RT induces different release of EVs and their cargo is altered. In addition, the uptake of EVs secreted by irradiated cells is affected. Hence, a deep investigation is required to better understand how RT influence the cell-to-cell communication thought signals shuttle by EVs. Here, detailed methods to study the RT effects on EV size and secretion, EV protein expression, EV uptake will be described. Alterations and adaptions might make the protocols applicable to different cell lines, and with different types of RT and dose exposures.

miR-218-5p-Modified Bone Marrow Mesenchymal Stem Cells Mediate the Healing Effect of EphrinB2-EphB4 Signals on Alveolar Bone Defect

Abnormally expressed miR-218-5p involves in alveolar bone defect. We intend to investigate whether miR-218-5p-modified bone marrow mesenchymal stem cells (BMSCs) mediates the healing effects of EphrinB2-EphB4 signals on the alveolar bone defect. Fifty germ-free rats (6-month-old) were utilized in this study. The grouping was set up as follows: blank group, model group, miR-218-5p group, EphrinB2-EphB4 antagonist group, and positive control group (10 rats in each group). HE staining was employed to quantify bone resorption lacunae number. And the following indicators were monitored: miR-218-5p expression, differentiation status of osteoblasts, concentrations of TNF-α/IL-10/ IL-8, and EphrinB2 and EphB4 expression. As shown in HE staining, massive infiltration of inflammatory cells was denoted at the alveolar bone defective sites in rats from model group. However, infiltration of inflammatory cells in lesions was moderate in rats from EphrinB2-EphB4 antagonist group and positive control group, which was accompanied by formation of small bone islands. Furthermore, lesser infiltration of inflammatory cells was denoted at the alveolar bone defective sites in rats from the miR-218-5p group, which also exhibited a larger number of newly formed bone trabeculae growing toward the center of lesions. On the 3rd day of culture, absorption lacunae were rare in the model group, while remaining undetectable in other groups. On the 7th day of culture, bone resorption lacunae number in samples from model group was significantly higher in comparison with that in other groups. Meanwhile, it was reduced significantly in miR-218-5p group. However, it was increased in EphrinB2-EphB4 antagonist group and positive control group (P <0.05). An elevation of the intracellular miR-218-5p level was denoted in the modified BMSCs in comparison with those unmodified BMSCs (P < 0.05). In comparison with blank group, other groups exhibited significantly elevated ALP levels, among which model group showed highest level. However, decline of ALP levels was denoted in positive control group, EphrinB2-EphB4 antagonist group and miR-218-5p group, with lowest ALP level in miR-218-5p group (P <0.05). Except blank group, rats in other groups exhibited a significant elevation of TNF-α, IL-10 and IL-8 in the serum, among which those in the model group displayed the most remarkable increase of these cytokines. Rats in miR-218-5p group, EphrinB2-EphB4 antagonist group and positive control group exhibited significantly reduced levels of IL-8, IL-10 and TNF-α in the serum, with miR-218-5p group showing lowest levels (P < 0.05). In comparison with the blank group, other groups showed significantly enhanced protein expression of EphrinB2 and EphB4, among which the model group displayed the most remarkable enrichment of these proteins. In comparison with the model group, samples from the miR-218-5p group, EphrinB2-EphB4 antagonist group and positive control group exhibited significantly weakened expression of EphrinB2 and EphB4, among which the miR-218-5p group displayed the most remarkable decrease of these proteins (P <0.05). miR-218-5p-modified BMSCs can modulate the EphrinB2-EphB4 signal transduction pathway to produce two-way transmission, which included their inhibition of the osteoclast generation and their enhancement of the osteoclast differentiation. In this way, they aided in alleviating inflammatory response in alveolar bone defective lesions, thereby accelerating the healing process of alveolar bone defect. The function of miR-218-5p-modified BMSCs is mainly achieved in the healing process of the alveolar bone defect.

miR-92a-3p encapsulated in bone metastatic mammary tumor cell-derived extracellular vesicles modulates mature osteoclast longevity

Aberrant osteoclast formation and activation are the hallmarks of osteolytic metastasis. Extracellular vesicles (EVs), released from bone metastatic tumor cells, play a pivotal role in the progression of osteolytic lesions. However, the mechanisms through which tumor cell-derived EVs regulate osteoclast differentiation and function have not been fully elucidated. In this study, we found that 4T1 bone metastatic mouse mammary tumor cell-derived EVs (4T1-EVs) are taken up by mouse bone marrow macrophages to facilitate osteoclastogenesis. Furthermore, treatment of mature osteoclasts with 4T1-EVs promoted bone resorption, which was accompanied by enhanced survival of mature osteoclasts through the negative regulation of caspase-3. By comparing the miRNA content in 4T1-EVs with that in 67NR nonmetastatic mouse mammary tumor cell-derived EVs (67NR-EVs), miR-92a-3p was identified as one of the most enriched miRNAs in 4T1-EVs, and its transfer into mature osteoclasts significantly reduced apoptosis. Bioinformatic and Western blot analyses revealed that miR-92a-3p directly targeted phosphatase and tensin homolog (PTEN) in mature osteoclasts, resulting in increased levels of phospho-Akt. Our findings provide novel insights into the EV-mediated regulation of osteoclast survival through the transfer of miR-92a-3p, which enhances mature osteoclast survival via the Akt survival signaling pathway, thus promoting bone resorption.

Exosomes in bone remodeling and breast cancer bone metastasis

Exosomes are endosome-derived microvesicles that carry cell-specific biological cargo, such as proteins, lipids, and noncoding RNAs (ncRNAs). They play a key role in bone remodeling by enabling the maintenance of a balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Recent evidence indicates that exosomes disrupt bone remodeling that occurs during breast cancer (BC) progression. The bone is a preferred site for BC metastasis owing to its abundant osseous reserves. In this review, we aimed to highlight the roles of exosomes derived from bone cells and breast tumor in bone remodeling and BC bone metastasis (BCBM). We also briefly outline the mechanisms of action of ncRNAs and proteins carried by exosomes secreted by bone and BCBM. Furthermore, this review highlights the potential of utilizing exosomes as biomarkers or delivery vehicles for the diagnosis and treatment of BCBM.

Muscle and Bone Defects in Metastatic Disease

PURPOSE OF REVIEW

The present review addresses most recently identified mechanisms implicated in metastasis-induced bone resorption and muscle-wasting syndrome, known as cachexia.

RECENT FINDINGS

Metastatic disease in bone and soft tissues is often associated with skeletal muscle defects. Recent studies have identified a number of secreted molecules and extracellular vesicles that contribute to cancer cell growth and metastasis leading to bone destruction and muscle atrophy. In addition, alterations in muscle microenvironment including dysfunctions in hepatic and mitochondrial metabolism have been implicated in cancer-induced regeneration defect and muscle loss. Moreover, we review novel in vitro and animal models including promising new drug candidates for bone metastases and cancer cachexia. Preservation of bone health could be highly beneficial for maintaining muscle mass and function. Therefore, a better understanding of molecular pathways implicated in bone and muscle crosstalk in metastatic disease may provide new insights and identify new strategies to improve current anticancer therapeutics.

Advancing Treatment of Bone Metastases through Novel Translational Approaches Targeting the Bone Microenvironment

Bone metastases represent a lethal condition that frequently occurs in solid tumors such as prostate, breast, lung, and renal cell carcinomas, and increase the risk of skeletal-related events (SREs) including pain, pathologic fractures, and spinal cord compression. This unique metastatic niche consists of a multicellular complex that cancer cells co-opt to engender bone remodeling, immune suppression, and stromal-mediated therapeutic resistance. This review comprehensively discusses clinical challenges of bone metastases, novel preclinical models of the bone and bone marrow microenviroment, and crucial signaling pathways active in bone homeostasis and metastatic niche. These studies establish the context to summarize the current state of investigational agents targeting BM, and approaches to improve BM-targeting therapies. Finally, we discuss opportunities to advance research in bone and bone marrow microenvironments by increasing complexity of humanized preclinical models and fostering interdisciplinary collaborations to translational research in this challenging metastatic niche.

Immune Modulation of Metastatic Niche Formation in the Bone

Bone metastasis is commonly seen in patients with breast cancer, prostate cancer and lung cancer. Tumor-intrinsic factors and the tumor microenvironment cooperate to affect the formation of bone metastatic niche. Within the bone microenvironment, immune cells have been regarded as a major contributor to metastatic progression. In this review, we describe the dynamic roles of immune cells in regulating metastatic homing, seeding, dormancy, and outgrowth in the bone. We also summarize the diverse functions of immune molecules including chemokines, cytokines, and exosomes in remodeling the bone metastatic niche. Furthermore, we discuss the therapeutic and prognostic potential of these cellular and molecular players in bone metastasis.