In vitro screening of Lactiplantibacillus plantarum with probiotic properties and anti-colon cancer potential

Colorectal Cancer (CRC), is a common malignant tumor of the gastrointestinal tract, with a high incidence and mortality rate. Recently, probiotics have received much attention as dietary supplements in the prevention and treatment of chronic diseases. Lactic acid bacteria (LAB) with anti-colon cancer potential were screened from 472 strains derived from fecal and Paocai (a traditional Chinese fermented vegetable) samples. Twenty strains were screened via their anti-colon cancer potential (inhibit the proliferation and migration of colon cancer cells, inhibit Fusobacterium nucleatum, produce short-chain fatty acids (SCFAs), and the probiotic properties (acid and bile salt resistance and adhesion properties)). Three LAB strains were obtained according to the optimal score through principal component analysis, including Lactiplantibacillus plantarum NCU0011098, Lactiplantibacillus plantarum NCUH001084, and Lactiplantibacillus plantarum NCU0011129, which have the favorable antibacterial ability and antioxidant activity. Moreover, these strains can increase the reactive oxygen species (ROS) levels in HT-29 cells. Interestingly, the cell-free supernatant (CFS) of the three strains could up-regulate the pro-apoptotic genes Bax and Bad, and down-regulate the anti-apoptotic genes Bcl-xl. In addition, Cyto-C and Caspase 9 were also upregulated. Therefore, these strains may exert their anti-tumor effects by promoting apoptosis in cancer cells through the mitochondrial apoptosis mechanism. These findings contributed to the efficient screening and utilization of anti-colon cancer LAB.