Abstract：In recent years， the tremendous potential of bacterial outer membrane vesicles (OMVs) in anti-tumor therapy has attracted wide attention. To investigate the effect of Salmonella enterica serovar Typhi outer membrane vesicles (S. Typhi-OMVs) on the proliferation of human colorectal cancer cell line HT-29 and the possible mechanism of action， the outer membrane vesicles of different bacteria were extracted by ultracentrifugation. Cell proliferation assay (CCK-8) was performed to detect the effect of each bacterial outer membrane vesicles on HT-29 cell viability. Transcriptome sequencing was used to analyze the changes of gene expression levels in HT-29 cells after S. Typhi-OMVs treatment. The content changes of ferroptosis related markers were detected with the corresponding kits. Quantitative real-time polymerase chain reaction and western blot were applied to detect the changes of mRNA and protein expression of related genes， respectively. The results showed that S. Typhi-OMVs had the most significant inhibitory effect on the proliferation of HT-29 among the six bacterial outer membrane vesicles， and the inhibitory effect showed concentration and time gradient dependence. RNA-seq revealed that ferroptosis may have occurred in HT-29. After S. Typhi-OMVs treatment， intracellular iron deposition occurred， oxidative products increased， and antioxidants decreased， which was consistent with the biochemical characteristics of ferroptosis. SAT1 was the gene with the largest mRNA expression change. The p53-SAT1-ALOX15 is one of the signaling pathways of ferroptosis， and the mRNA and protein expressions of p53， SAT1 and ALOX15 were all increased after S. Typhi-OMVs treatment of HT-29. The above results suggest that S. Typhi-OMVs were able to inhibit the proliferation of colorectal cancer cells HT-29， and the mechanism might be related to the induction of ferroptosis in HT-29 through the p53-SAT1-ALOX15 signaling pathway.
2024, Vol. 58 
