Fungal Exosome-Like Nanoparticles from Huaier (Trametes robiniophila Murr.) Exhibit Antibreast Cancer Activity.

Breast cancer (BC) is a leading cause of morbidity and mortality among females globally. Despite advances in treatment, the disease remains a significant public health challenge. Recently, exosomes and exosome-like nanoparticles (ELNs) derived from various organisms have emerged as potential therapeutic agents. This study aimed to investigate the effects of Huaier (Trametes robiniophila Murr.)-derived ELNs on the viability and behavior of human BC cells and to explore the underlying mechanisms, including the role of microRNAs (miRNAs). Huaier ELNs were isolated and purified from Huaier through differential ultracentrifugation. In vitro assays, including Cell Counting Kit-8, colony formation, flow cytometry, transwell invasion, and wound healing assays, were used to assess cell viability, migration, and invasion. In vivo, a murine model was employed to study tumor growth. RNA sequencing, miRNA sequencing, quantitative polymerase chain reaction, and dual-luciferase reporter assays were performed to identify the molecular mechanisms, particularly focusing on oncogenic signaling pathways and miRNA involvement. Huaier ELNs significantly suppressed BC cell proliferation, migration, and invasion in vitro. In vivo, they resulted in substantial inhibition of tumor growth. RNA and miRNA sequencing revealed that Huaier ELNs modulated the expression of multiple genes associated with oncogenic pathways, and miRNAs enriched in the ELNs played key roles in a cross-kingdom regulatory mechanism. Huaier-derived ELNs exhibit potential as a therapeutic agent for BC, showing significant antitumor effects both in vitro and in vivo. The study highlighted the involvement of miRNAs in the regulation of oncogenic signaling pathways, offering a new perspective for therapeutic strategies targeting BC.