Introduction: lactic acid bacteria as probiotics have seized great attention in adjuvant chemotherapy of different cancer types as well as cervical cancer. To investigate the anti­cancer potential of Iranian novel strains, two local Lactobacillus including acidophilus and paracasei and, mix of them were selected to treat on human cervical cancer cell line compared to normal control cells.
Methods: The cytotoxic effect of Lactobacillus acidophilus and paracasei supernatants and their 1:1 mixture on CaSki and HNCF PI 52 cell lines was analyzed through MTT assay. Apoptotic and anti-metastatic effects of the used supernatants were assessed by gene expression analysis of BAX/BCL2 ratio and CASPASE-3 and, MMP2/MMP9 genes, respectively, through Real-Time reverse transcriptase polymerase chain reaction (RT-PCR).
Results: Significant cytotoxicity was observed in CaSki cells due to the low pH of the supernatants. The increase in the BAX/BCL 2 ratio and consequent up-regulation of CASPASE 3 showed that low pH could induce apoptosis (P<0.001). In addition, expression level of MMP9 was significantly down-regulated in CaSki cells treated with Lactobacillus
acidophilus (P<0.001) and Lactobacillus paracasei (P<0.05) while no significant difference was observed in the MMP2 expression in all the samples compared to control groups.
Conclusion: Although, it requires further confirmation, high apoptotic gene expression indexes can be interpreted as apoptosis induced cancer cells to survive in response to Lactobacillus toxicity. Significant down-regulation of MMP9 gene warrants further comparative analysis on different cervical cancer cells to prove anti-metastatic potentials of local probiotics supernatant.