Sugimura N, Li Q, Chu ESH, et al. - Studies have described the depletion of Lactobacillus gallinarum in patients with colorectal cancer (CRC) using faecal shotgun metagenomic sequencing. In this study, the potential antitumorigenic role of L. gallinarum in colorectal tumorigenesis has been investigated.

• Murine models of CRC were used to determine the tumor-suppressive effect of L. gallinarum.

• Cell proliferation, apoptosis and cell cycle distribution were evaluated by culturing CRC cell lines and organoids derived from patients with CRC with L. gallinarum or Escherichia coli MG1655 culture-supernatant.

• Intestinal tumor number and size reduced significantly in correlation with the presence of L. gallinarum vs E. coli MG1655 and phosphate-buffered saline in both male and female murine intestinal tumorigenesis models.

• L. gallinarum produces protective metabolites that can promote apoptosis of CRC cells and thereby protects against intestinal tumorigenesis.