α-pinene effects on the anticancer properties of Lactobacillus acidophilus probiotics against colorectal cancer cells.

[BACKGROUND] Colorectal cancer (CRC) is the third most prevalent cancer and the second leading cause of death globally. Despite numerous studies conducted on various aspects of CRC, challenges remain regarding the most effective prevention and treatment strategies. () is a Gram-positive, nonsporulating bacterium found in the gastrointestinal tract. Certain fermented foods are widely recognized for their probiotic properties. α-pinene is an organic monoterpene found in many aromatic plants such as conifers, eucalyptus, mint, holy basil, amphora, etc. It is known to have antimicrobial, anti-metastatic, anti-apoptotic, and antibiotic properties. This study aimed to explore the impact of long-term adaptation of to α-pinene on the antimicrobial and anticancer properties of its cell-free supernatants (CFS). In the first stage, the inhibitory effects of CFSs of α-pinene treated bacteria (αP-CFS) and untreated bacteria (CFS), on the proliferation and biofilm formation abilities of various pathogenic bacterial species were assessed. Subsequently, using cellular and molecular methods such as MTT, Annexin V/PI staining, cell cycle analysis, colony formation, scratch, and quantitative real time-PCR (qRT-PCR), the anticancer properties of CFSs on HCT-116 cells were investigated.

[RESULTS] Our results indicated that both CFSs inhibited the proliferation and biofilm formation of pathogenic bacteria, and the antimicrobial effect of αP-CFS being significantly greater than that of CFS. In comparison to CFS, HCT-116 treatment by αP-CFSs demonstrated greater suppression in cell proliferation and increased induction of apoptosis. This effect was mediated by modulating apoptotic genes, including , , , and , highlighting the enhanced potency of αP-CFS compared to CFS. Cell cycle analysis indicated that αP-CFS significantly increased cell cycle arrest at the Sub-G1 stage compared to CFS. Colony formation and scratch assays demonstrated that αP-CFS is more effective than CFS in inhibiting colony formation and cell migration. Furthermore, qRT-PCR analysis demonstrated that αP-CFS significantly reduced the expression of and compared to CFS.

[CONCLUSIONS] These findings suggest that the long-term adaptation of to α-pinene enhances the antimicrobial and anticancer properties of its CFS, suggesting this approach as a promising strategy for CRC treatment.