Background and Aim: Breast cancer is the most common type of cancer in women because it attacks the productive age. Preliminary studies showed that lactic acid bacteria (LAB) strain SR6 from the Bali cattle colon has the potential to act as a superior probiotic. It is also assumed that its bacteriocin structure is specific and has a strong relationship with the specificity of the ligand and its biological activity at a receptor. Therefore, this study aims to assess the use of local LAB strains, which produce bacteriocins as anticancer agents, as well as to identify the bacteria as potent producers molecularly.

Materials and Methods: The study was initiated by cultivating LAB SR6 strain from stock isolates on De Man, Rogosa, and Sharpe (Oxoid, CM 0369, England) broth media. It was then confirmed molecularly through analysis of the 16S ribosomal ribonucleic acid gene. Subsequently, its anticancer activity was tested by assessing the cytotoxic activity in T47D cell culture using the 3-(4, 5 dimetiltiazol-2-yl)-2.5-diphenyl tetrazolium bromide (Invitrogen M6494, US) method.

Results: The results showed that the LAB strain SR6 was identified molecularly as Pediococcus pentosaceus. Furthermore, it had a toxic effect on T47D cells, which was indicated by the number of deaths after treatment with the extracellular protein of the strain, especially at the 50% total cell volume level.

Conclusion: Based on the toxic effect of the strain on human T47D cells, the LAB SR6 isolate, which was identified as P. pentosaceus has the potential to be developed as a good anticancer drug against breast cancer. However, there is a need to carry out an integrated study to fully explore the suitability of bacteriocins as in vivo therapeutics against the disease completely.

Keywords: apoptosis, breast cancer, lactic acid bacteria SR6 strain, necrosis.