L-asparaginase from human breast milk Lactobacillus reuteri induces apoptosis using therapeutic targets Caspase-8 and Caspase-9 in breast cancer cell line.

Background: Breast cancer is the most fatal type of cancer in women worldwide. Many chemotherapeutics targeted breast cancer however, they have frightening side effects. One method of controlling cancer cell growth is targeting apoptosis.

Objective: This study aimed to induce apoptosis in breast cancer cells by purifying L-asparaginase from human breast milk Lactobacillus reuteri isolates via inhibition of Caspases 8 and 9.

Methods: The best L. reuteri isolates producing L-asparagine with the highest enzyme activity were identified from human breast milk and chosen for L-asparaginase purification. The MTT cell viability assay used for measure the toxicity of the enzyme. Breast cancer cell line was used to study the effect of the enzyme on the caspase 8 and caspase 9 gene expression.

Results: The MTT cell viability assay showed the inhibition rates ranged between 30% and 80%, of cell death, occurred when 3.125, 6.25, 12.5, 25, 50, and 100 μg/ml of the enzyme used and IC50 was 4.305 μg/ml. The breast cell lines were treated with the enzyme at a concentration of IC50 value. The Cas8 and Cas9 genes expression in L-asparagine treated breast cancer cell line at a concentration of IC50 value were upregulated (the fold of gene expression are 2.071 and 1.197 respectively).

Conclusions: Breast milk L. reuteri L-asparaginase induces apoptosis via Cas8 and Cas9 upregulation in the breast cancer cell line. L. reuteri L-asparaginase treatment may be the hopeful approach for the management of breast cancer. Furthermore, the results may highlight the fact that the presence of L-asparaginase-producing L. reuteri isolates in human breast milk may aid in breast cancer improvement or even prevention.