Probiotic nanovesicles encapsulating baicalin: a strategy to overcome colorectal cancer

Escherichia coli Nissle 1917 (EcN) is a unique probiotic utilized to treat inflammatory bowel disease and irritable bowel syndrome. Outer membrane vesicles (OMVs) from EcN can not only deliver pro-biotic anti-inflammatory molecules to cancer cells to exert anti-rectal cancer effects, but also deliver therapeutic drugs, genes, and other "cargoes" encapsulated in the vesicles to specific cells, making them an ideal vehicle for drug delivery. In this study, we successfully isolated OMVs of probiotic origin and obtained BCN-OMVs by encapsulating baicalin (BCN) in EcN-OMVs. Fluorescence microscopy showed that both fluorescently labeled EcN-OMVs and BCN-OMVs were able to enter HT-29 cells. The results of CCK-8, plate cloning, flow cytometry, and western blotting indicated that the vitality and proliferation of HT-29 cells were sensibly inhibited after treatment with BCN-OMVs. Additionally, apoptosis-related proteins and proteins involved in the NF-κB pathway were also expressed differently. The results above suggest that EcN-OMVs, serving as a bio-nanocarrier of BCN, can effectively address the limitations of BCN, such as poor water solubility and low bioavailability. They also play a significant anti-tumor role by enhancing cancer cell apoptosis, showing promising potential in targeted therapy for colorectal cancer (CRC).