Exosome-mediated transduction of mechanical force regulates prostate cancer migration via microRNA

Visualization of Mechanical Force Regulation of Exosome Secretion Using High Time-Spatial Resolution Imaging

Exosomes are small endosome-derived extracellular vesicles that participate in cell-cell communication, particularly in the context of tumorigenesis, and their secretion is influenced by the tumor microenvironment. While previous studies suggest that mechanical forces may enhance exosome release, the direct relationship between these forces and exosome secretion needs to be further characterized. Here, we utilized dual-color CD63 reporter-based high-speed live-cell imaging to visualize how mechanical forces influence exosome release in situ. Through live-cell tracking, we observed the dynamic fusion of multivesicular bodies (MVBs) with the plasma membrane (PM) to release exosomes at the single-vesicle level. More importantly, we directly detected a real-time stimulatory effect of mechanical forces on exosome release, with a bulk release of exosomes occurring under mechanical pressure stimulation. Furthermore, we identified mechanical force-induced actin rearrangement as a crucial determinant of exosome release. Our findings provide direct insights into the role of mechanical forces in exosome release and lay the groundwork for developing potential strategies to target disease-derived exosomes from their source.

Selective Suppression of Integrin-Ligand Binding by Single Molecular Tension Probes Mediates Directional Cell Migration

Cell migration interacting with continuously changing microenvironment, is one of the most essential cellular functions, participating in embryonic development, wound repair, immune response, and cancer metastasis. The migration process is finely tuned by integrin-mediated binding to ligand molecules. Although numerous biochemical pathways orchestrating cell adhesion and motility are identified, how subcellular forces between the cell and extracellular matrix regulate intracellular signaling for cell migration remains unclear. Here, it is showed that a molecular binding force across integrin subunits determines directional migration by regulating tension-dependent focal contact formation and focal adhesion kinase phosphorylation. Molecular binding strength between integrin αvβ3 and fibronectin is precisely manipulated by developing molecular tension probes that control the mechanical tolerance applied to cell-substrate interfaces. This data reveals that integrin-mediated molecular binding force reduction suppresses cell spreading and focal adhesion formation, attenuating the focal adhesion kinase (FAK) phosphorylation that regulates the persistence of cell migration. These results further demonstrate that manipulating subcellular binding forces at the molecular level can recapitulate differential cell migration in response to changes of substrate rigidity that determines the physical condition of extracellular microenvironment. Novel insights is provided into the subcellular mechanics behind global mechanical adaptation of the cell to surrounding tissue environments featuring distinct biophysical signatures.

ECM stiffness affects cargo sorting into MSC-EVs to regulate their secretion and uptake behaviors

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have garnered extensive attention as natural product-based nanomedicines and potential drug delivery vehicles. However, the specific mechanism for regulating MSC-EVs secretion and delivery remains unclear. Here, we demonstrate that extracellular matrix (ECM) stiffness regulates the secretion and delivery of EVs by affecting MSCs' cargo sorting mechanically. Using multi-omics analysis, we found that a decrease in ECM stiffness impeded the sorting of vesicular transport-related proteins and autophagy-related lipids into MSC-EVs, impairing their secretion and subsequent uptake by macrophages. Hence, MSC-EVs with different secretion and uptake behaviors can be produced by changing the stiffness of culture substrates. This study provides new insights into MSC-EV biology and establishes a connection between MSC-EV behaviors and ECM from a biophysical perspective, providing a basis for the rational design of biomedical materials.

Diversity of Intercellular Communication Modes: A Cancer Biology Perspective

From the moment a cell is on the path to malignant transformation, its interaction with other cells from the microenvironment becomes altered. The flow of molecular information is at the heart of the cellular and systemic fate in tumors, and various processes participate in conveying key molecular information from or to certain cancer cells. For instance, the loss of tight junction molecules is part of the signal sent to cancer cells so that they are no longer bound to the primary tumors and are thus free to travel and metastasize. Upon the targeting of a single cell by a therapeutic drug, gap junctions are able to communicate death information to by-standing cells. The discovery of the importance of novel modes of cell-cell communication such as different types of extracellular vesicles or tunneling nanotubes is changing the way scientists look at these processes. However, are they all actively involved in different contexts at the same time or are they recruited to fulfill specific tasks? What does the multiplicity of modes mean for the overall progression of the disease? Here, we extend an open invitation to think about the overall significance of these questions, rather than engage in an elusive attempt at a systematic repertory of the mechanisms at play.

Exosomal DNA: Role in Reflecting Tumor Genetic Heterogeneity, Diagnosis, and Disease Monitoring

Extracellular vesicles (EVs), with exosomes at the forefront, are key in transferring cellular information and assorted biological materials, including nucleic acids. While exosomal RNA has been thoroughly examined, exploration into exosomal DNA (exoDNA)-which is stable and promising for cancer diagnostics-lags behind. This hybrid genetic material, combining contributions from both nuclear and mitochondrial DNA (mtDNA), is rooted in the cytoplasm. The enigmatic process concerning its cytoplasmic encapsulation continues to captivate researchers. Covering the entire genetic landscape, exoDNA encases significant oncogenic alterations in genes like TP53, ALK, and IDH1, which is vital for clinical assessment. This review delves into exosomal origins, the ins and outs of DNA encapsulation, and exoDNA's link to tumor biology, underscoring its superiority to circulating tumor DNA in the biomarker arena for both detection and therapy. Amidst scientific progress, there are complexities in the comprehension and practical application of the exoDNA surface. Reflecting on these nuances, we chart the prospective research terrain and potential pitfalls, forging a path for future inquiry. By illuminating both the known and unknown facets of exoDNA, the objective of this review is to provide guidance to the field of liquid biopsy (LB) while minimizing the occurrence of avoidable blind spots and detours.

Extracellular signals regulate the biogenesis of extracellular vesicles

Extracellular vesicles (EVs) are naturally released membrane vesicles that act as carriers of proteins and RNAs for intercellular communication. With various biomolecules and specific ligands, EV has represented a novel form of information transfer, which possesses extremely outstanding efficiency and specificity compared to the classical signal transduction. In addition, EV has extended the concept of signal transduction to intercellular aspect by working as the collection of extracellular information. Therefore, the functions of EVs have been extensively characterized and EVs exhibit an exciting prospect for clinical applications. However, the biogenesis of EVs and, in particular, the regulation of this process by extracellular signals, which are essential to conduct further studies and support optimal utility, remain unclear. Here, we review the current understanding of the biogenesis of EVs, focus on the regulation of this process by extracellular signals and discuss their therapeutic value.