Putative probiotics decrease cell viability and enhance chemotherapy effectiveness in human cancer cells: role of...

Area of Science:

• Microbiology
• Cancer Biology
• Gastroenterology

Background:

• Probiotics demonstrate potential in preventing colorectal cancer through mechanisms like promoting differentiation and inducing apoptosis.
• Investigating specific probiotic strains and their bioactive compounds is crucial for understanding their anti-cancer effects.

Purpose of the Study:

• To evaluate the ability of ascertained and food-isolated probiotics to inhibit colorectal cancer cell proliferation.
• To investigate the role of secreted metabolites (SCFAs, EPS, extracellular proteins) in the anti-proliferative effects of probiotics.
• To assess the impact of probiotic-derived compounds on chemoresistant cancer cells and their response to doxorubicin.

Main Methods:

• Assessed adherence and proliferation inhibition of HT29 and HT29-dx cells by selected probiotic strains.
• Tested the efficacy of extracellular extracts and butyrate, with or without doxorubicin, on cancer cell viability.
• Analyzed mitochondrial reactive oxygen species (ROS) production and performed comparative phenotypic and secretome analyses.

Main Results:

• Three food-isolated probiotics (L. plantarum S2, L. pentosus S3, L. rhamnosus 14E4) reduced viability in both sensitive and chemoresistant HT-29 cells.
• Extracellular extracts and doxorubicin treatment decreased cancer cell viability, with increased ROS production observed.
• Differences in exopolysaccharide (EPS) content and protein profiles, including phage-tail-like and capsid-like proteins, were noted between effective and non-effective strains.

Conclusions:

• Food-isolated bacteria producing bioactive compounds like butyrate, EPS, and specific proteins can control cancer cell proliferation.
• These findings suggest a potential role for these probiotics and their metabolites in improving chemotherapy response in colorectal cancer.