Bifidobacterium bifidum does not show cell toxicity on leukemic cells of AML patients but induced cell death on K562 cell line

Leukemia is a kind of blood cancer diseases which are generally known as neoplasm. There are two types of blood cancer called acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). This type of leukemia targets plasma cells and prevents the production of antibodies in the body and makes the immune system vulnerable to infections.

Blood samples from 10 people with AML and 10 normal individuals were collected who were defined as the case and control groups, respectively. PBMCs were isolated by Ficoll hypaque and cultured in order to the MTT assay. Then, the cell wall of Bifidobacterium bifidum bacterium was treated in five concentrations on these cells and the MTT test was performed at 24, 48 and 72hrs. Also, K562 leukemia cell was cultured then after; the MTT test was performed in the same protocol. The expression of BAX, Bcl2, β-actin genes were assessed by real-time PCR after 48 and 72hrs of treatment.

 The results of MTT test could not show any significant differences in extracted PBMCs from individuals as compared to control group. But, K562 cell line in treatment with the cell wall of Bifidobacterium bifidum showed a significant cell toxicity effect at 48 and 72hrs versus non-treated K562 cells. BAX gene expression was significantly increased versus β-actin gene control only on K562 cell line, but not on AML derived leukemic cells.

According to the obtained results, Bifidobacterium bifidum, as a probiotic bacterial species, can impact the growth and/or proliferation of cancer cells; however, it could depend on the type of cancer cells.