Alborz University

Introduction: Lactococcus lactis bacteria are used as a useful probiotic in treating and preventing cancer and can inhibit the growth of other bacteria by producing bacteriocins. The present study aimed to investigate the effects of probiotic lysate of Lactococcus lactis (+ NIS) on the expression of efflux pump genes of Proteus mirabilis and some anti-apoptotic genes in kidney cancer cell lines.
Methods: After examining and isolating 60 strains of Proteus mirabilis by diagnostic and biochemical tests, a Multiplex PCR reaction was performed to identify the efflux pump genes of Proteus mirabilis. The bacteria were cultured and the supernatant of the nisin-producing microorganism Lactococcus lactis strain (PTCC 1336) was isolated and its activity was examined by plating on agar. By Real-Time PCR reaction, the expression of the acrB gene in the Proteus mirabilis strains treated with supernatant was examined.
Results: The cytotoxicity result of this supernatant for the relative expression of bcl-2 and bax genes in kidney cancer cells was that among the Proteus mirabilis samples, 37 samples had the acrA gene, 59 samples had the acrB gene, and 58 samples had the Urea gene. The results of the MIC test showed inhibition of the growth of Proteus strains at a concentration of 375 μg/ml of the supernatant. The expression of the acrB gene in the treated strains was significantly decreased compared to the control group. According to the analysis of MTT test data, the half-maximal inhibitory concentration (IC50) for this supernatant was calculated to be 202.8 μg/ml after 72 hours.
Conclusion: The results showed a 52.86% decrease in bcl-2 gene expression and a 60.21% increase in bax gene expression in treated cancer cells compared to the control group. Cytotoxicity studies of this study showed that it could suppress the proliferation of renal cell carcinoma (ACHN) cells with an IC50 of 202.8 μg/ml.