Lactobacillus Plantarum and its Derived Bacteriocin Exhibits PotentAntitumor Activity against Esophageal Cancer Cells

Esophageal cancer presents a challenge in gastroenterology and traditional chemotherapy and
radiation therapy have less therapeutic activity with severe side effects. Thus, there is need for
effective and safer alternatives. Probiotics, particularly Lactobacillus plantarum (L. plantarum)
and its bacteriocins, might prevent or treat esophageal tumors. We aimed to investigate the use
of L. plantarum and its bacteriocin as esophageal cancer therapy. First, we obtained 100 isolates
of Lactobacillus spp. from dairy product samples. They screened for bacteriocin production and
identified by PCR and gel electrophoresis for 16S ribosomal RNA gene. Bacteriocin was partially
purified and tested against two different pathogens. Both L. plantarum and its bacteriocin were
examined for cytotoxicity in vitro against esophageal cancer cell line (SK-GT4) and normal rat
embryo fibroblast (REF) cells by MTT assay. Apoptosis was determined using an acridine orange
/propidium iodide assay. The results showed that the isolate gives a high bacteriocin production
about (2000AU/ml). In addition to antimicrobial activity, there was significant anticancer
activity. L. plantarum had an IC50 of 51.01 CFU/ml and bacteriocin IC50 of 281.9 AU/ml against
cancer cells. Both showed no cytotoxicity towards normal REF cells. Furthermore, there was a
significant increase in apoptosis induction and in caspase-3 activity in cancer cells treated with
L. plantarum and bacteriocin compared to untreated cells. In conclusion, L. plantarum and its
bacteriocin show potent killing effect against esophageal cancer cells with no effect against
normal cells indicating safety and selectivity with activation of apoptosis via caspase-3 induction
suggesting potential clinical advantage.