Bovine Colostrum-Derived Extracellular Vesicles Impair Cancer Cell Proliferation Through Transcriptional Dysregulation.

Milk-derived extracellular vesicles (EVs) are a promising source of molecules with therapeutic potential. Bovine colostrum is particularly enriched in EVs, which carry cargo of proteins involved in immune regulation, development and cellular signalling. Some studies have explored their role as bioactive anti-cancer agents, however, their mechanistic effects remain underexplored. Here, we show that colostrum-derived EVs (Col-EVs) exert anti-proliferative effects in gastrointestinal cancer models, including cell lines and patient-derived organoids, which is independent of apoptosis induction. Using a multi-modal approach combining proteomics, imaging and functional assays, we demonstrate that Col-EVs induce a reversible growth-arrest state, characterized by widespread transcriptional and RNA-processing dysregulation, chromatin compaction, nuclear reorganization and cytoskeletal remodelling. Proteomic analyses reveal that Col-EV treatment disrupts key components of the transcriptional machinery and cell cycle regulatory pathways, effects that are reversible upon EV withdrawal and can be rescued pharmacologically using an EZH2 inhibitor. Col-EVs enhance the sensitivity of cancer cells as well to DNA-targeting chemotherapies such as 5-fluorouracil, indicating their potential as modulatory adjuvants rather than cytotoxic agents. Overall, our findings reveal that Col-EVs can reversibly suppress cancer cell proliferation by reprogramming transcriptional and nuclear architecture, offering a natural, biocompatible strategy for modulating tumour growth and sensitizing cancer cells to conventional therapies.