Molecular detection of heat-killed probiotic bacteria and study of apoptosis induction on colon cancer HT-29 cell line

Due to the high prevalence of colon cancer in human societies such as Iran, the aim of this study is the molecular identification and assesses cytotoxic effects of heat-killed probiotic bacteria and induced apoptosis in HT-29 cell lines of colon cancer compared with normal cells.
Molecular detection was performed on local probiotic bacteria isolated (TD4) from Tarkhineh dough. Both cell lines HT-29 colon cancer and HEK-293 were affected by 0.01, 0.1, 1, 10, 100, and 1000 µg/ml of heat-killed TD4 isolate for periods of 24, 48, and 72 hours. Cell viability was measured using MTT assay. DNA fragmentation assay was performed after 48 and 72 hours base on the IC50 concentration of heat-killed bacteria.
TD4 isolate was submitteded lactobacillus berevis in GenBank. According to MTT assay, lactobacillus berevis depended on time and dose reduced survival and proliferation of colon cancer of HT-29 cell line, with the highest cytotoxic effect in 1000 µg/ml for 72 hours. At this dose and time, viability was 23% and 50% in HT-29 and HEK-239 cell lines, respectively. DNA fragmentation assay showed apoptosis induction by heat-killed bacteria in the HT-29 cell line.
L.berevis showed cytotoxic effects and induced apoptosis on HT-29 colon cancer cell line while the cytotoxic effect was slight on HEK-239 compared to HT-29. Future studies are still required to confirm these bacteria as a biological anti-cancer product in treatment and prevention.