Cell-Free Supernatant of L. buchneri Probiotic Bacteria Enhancing Apoptosis Activity in AGS Gastric Cancer Cells

The current study aimed to evaluate the cytotoxic activity and apoptosis induction of cell-free supernatants (CFS) from Lactobacillus buchneri of traditional dairy products on the AGS gastric cancer cell line. Molecular identification of probiotic L. buchneri was carried out using 16S rRNA PCR and sequencing. MTT assay, Annexin V-FITC, qRT-PCR, and cell cycle analysis were conducted to evaluate the induction of apoptosis in AGS-treated cells. The L. buchneri CFS inhibited the proliferation of AGS cancer cells in a dose- and time-dependent manner, which had great anticancer activity at 200 µg/mL after 72 h. Flow cytometry results confirmed the highest rate of apoptosis in cancer cells treated with IC₅₀ concentration of CFS after 72 h. L. buchneri supernatant also triggered the up-regulation of pro-apoptotic genes including BCL2-associated X, caspase 9, and caspase 3 genes. Treatment of cancer cells with CFS at IC₅₀ concentration caused the cell cycle arrest in the sub-G1 phase in a time-dependent manner. This study revealed that L. buchneri obtained from Iranian traditional yogurt may protect the host from gastric cancer by triggering apoptosis in cancer cells. Therefore, L. buchneri supernatant can be employed as a biological anticancer agent in the management and treatment of gastric cancer.