Evaluation of Anti-Tumor Potential of Lactobacillus acidophilus ATCC4356 Culture Supernatants in MCF-7 Breast Cancer.

BACKGROUND Anti-cancer activity of some lactic acid bacterial strains is well documented in several literatures. Lactobacillus strains have received considerable attention as a beneficial microbiota. The aim of this study is to evaluate the effects of anti-tumor activities of L. acidophilus ATCC4356 culture supernatants on the MCF-7 human breast cancer cells. MATERIALS AND METHODS Anti-cancer effect of 24h and 48h culture supernatants at various concentrations (1.25, 2.5, 5, 10 and 20 µg/ml) were determined by various in vitro and in vivo assays including MTT, tumor volume measurement as well as 99mTc-MIBI biodistribution in MCF-7 tumor bearing nude mice and histopathology test. For evaluation of the related mechanism of action, quantitative PCR was conducted. RESULTS The 48h culture supernatants at 10 and 20 µg/ml exhibited significant in vitro inhibition of MCF-7 cell proliferation. However, this inhibition was not observed for HUVEC human endothelial normal cells. Q-PCR indicated that treatment by the supernatant led to a significant downregulation of VEGFR ( 0.009 fold) and Bcl-2 ( 0.5 fold) and upregulation of p53 ( 1.3 fold). In vivo study using MCF-7 xenograft mouse models demonstrated reduction in tumor weight and volume by both 24h and 48h supernatants (10 µg/ml and 20 µg/ml) after 15 days. According to the 99mTc-MIBI biodistribution result, treatment of MCF-7 bearing nude mice with both 24h and 48h supernatant (20 µg/ml) led to significant decrease in tumor uptake compared with the control group. CONCLUSION These results suggest that the culture supernatants of L. acidophilus ATCC4356 at suitable concentrations can be considered as a good alternative nutraceutical with promising therapeutic indexes for breast cancer.