Osteosarcoma (OS), essentially the most prevalent main malignant bone tumor in youngsters and adolescents, represents a formidable medical problem because of its aggressive conduct and excessive propensity for pulmonary metastasis [1], [2]. Regardless of important developments in multimodal remedy, primarily mixture of neoadjuvant chemotherapy and radical surgical procedure, the challenges associated to chemotherapy resistance, tumor metastasis and recurrence nonetheless must be addressed [3], [4]. The metastatic course of in OS, though originating from mesenchymal tissue, shares convergent hallmarks with carcinomas, significantly the activation of applications akin to epithelial-mesenchymal transition (EMT). EMT endows tumor cells with enhanced migratory capability, invasiveness, and resistance to apoptosis, facilitating their escape from the first website and colonization of distant organs [5], [6], [7]. Due to this fact, unraveling the molecular drivers of EMT and growing methods to disrupt this program are essential for bettering OS outcomes.
Within the quest for novel therapeutic avenues, nanotechnology has emerged as a transformative frontier in oncology [8], [9], [10], [11], [12], [13]. Amongst varied nanomaterials, zinc oxide nanoparticles (ZnO NPs) have garnered substantial consideration owing to their glorious biocompatibility, selective cytotoxicity in direction of most cancers cells, and their designation as Typically Acknowledged as Protected (GRAS) by the U.S. Meals and Drug Administration (FDA) [14], [15]. Nonetheless, little in-depth exploration of therapeutic efficacy and mechanism of ZnO NPs on tumor metastasis, particularly in OS. Our earlier work demonstrated that ZnO NPs selectively inhibited OS cell proliferation and migration by an impact mechanistically linked to the intracellular launch of Zn2+ ions and the following stabilization and upregulation of hypoxia-inducible factor-1α (HIF-1α) [16]. HIF-1α is a grasp transcriptional regulator of the mobile adaptive response to hypoxia, a ubiquitous function of the stable tumor microenvironment. Past its position in glycolysis and angiogenesis, HIF-1α is a potent promoter of metastasis, influencing cell motility, invasion, and EMT [17], [18]. Nonetheless, the exact downstream effectors by means of which ZnO NP-induced HIF-1α exerts its anti-metastatic results in OS stay largely uncharted.
With the deepening understanding of microRNAs (miRNAs) as essential submit‑transcriptional regulators of gene expression, their essential roles in most cancers biology have been broadly acknowledged [19], [20]. Intriguingly, a major subset of miRNA genes harbor hypoxia-response components (HREs) of their promoter areas, rendering them direct transcriptional targets of HIF-1α [21], [22]. Nonetheless, figuring out which particular HIF-1α-regulated miRNAs are functionally answerable for mediating anti-metastatic results from the huge pool of intracellular miRNAs stays a frightening problem. Exosomes, naturally secreted nanovesicles (30–150 nm) of endocytic origin, have lately ascended to middle stage in intercellular communication analysis [23], [24]. Critically, tumor-derived exosomes can horizontally switch oncogenic data (together with miRNAs) to neighboring or distant cells, reprogramming the tumor microenvironment and pre-metastatic niches to favor metastasis [25], [26]. Conversely, this very property will be harnessed for therapeutic functions. Exosomes boast inherent benefits resembling low immunogenicity, excessive biocompatibility, stability in circulation, and an innate skill to cross organic obstacles, making them ideally suited candidates for drug supply and as sources of disease-specific biomarkers [27], [28]. In the meantime, the molecular profile of exosomes, significantly their miRNA content material, gives a concentrated and related snapshot of intracellular regulatory networks, doubtlessly simplifying the identification of key practical miRNAs in comparison with whole-cell evaluation [22], [29].
On this examine, we validate a novel bio-inspired technique utilizing ZnO NP-educated exosomes (termed ZnO‑Exos) secreted by OS cells. These modified ZnO‑Exos, upon internalization by recipient OS cells, ship a therapeutic molecular payload that disrupts the metastatic program by altering intracellular ionic and hypoxic signaling milieu. Via gene sequencing, molecular biology, and practical evaluation, we recognized that exosomal miR‑1287‑5p as a pivotal mediator was clearly upregulated. We additional delineated a whole signaling axis whereby ZnO‑Exos‑derived Zn2+ prompts HIF‑1α, which transcriptionally induces miR‑1287‑5p. This miRNA, in flip, straight targets and represses the mRNA of Snail, a key transcriptional repressor of E‑cadherin and a grasp regulator of EMT. By inhibiting Snail, the ZnO‑Exos‑delivered miR‑1287‑5p restored epithelial traits and blocks the migration and invasion of OS cells. Lastly, in a preclinical OS mannequin, we demonstrated the potent efficacy of ZnO‑Exos in suppressing orthotopic tumor progress and spontaneous lung metastasis with a superb security profile. Based mostly on above all, we display that ZnO NP-educated exosomes successfully reverse the EMT program, restore epithelial markers and cut back metastatic potential towards OS by Zn2+/HIF-1α/miR-1287–5p/Snail signaling axis (Scheme 1).
