The inhibitory impacts of Lactobacillus rhamnosus GG-derived extracellular vesicles on the growth of hepatic cancer cells

•EVs from probiotic can provoke cytotoxic effects on the cancer cells related to organs out of the gastrointestinal tract.•The apoptotic index (bax/bcl-2 expression ratio) was significantly increased after treating with probiotic EVs.•Probiotic EVs resulted in activation of the apoptosis and cancer cell death.

Bacterial extracellular vesicles (EVs) have come forth into notice as possible important agent to mediate host-pathogen interactions. In this scientific research, the authors have tried to find out the effect of EVs derived from Lactobacillus rhamnosus GG (LDEVs) on the apoptosis induction in HepG2 cell line. The EVs were purified from the conditioned medium of Lactobacillus rhamnosus GG using ultrafiltration and confirmed by transmission electron microscopy (TEM). The HepG2 cells were treated with different concentrations of purified LDEVs and the cytotoxicity and their effects on the expression of bcl-2 and bax genes were assessed by the MTT assay and semi-quantitative RT-PCR, respectively. The MTT assay showed that only 100 μg/ml of LDEVs had a significant cytotoxic effect on cancer cells (p < 0.05). The apoptotic index (bax/bcl2 expression ratio) was significantly increased after treating with 50 and 100 μg/ml LDEVs (p < 0.05). Increased bax/bcl-2 ratio was led to cancer cell death.