In Vivo Investigation of Supportive Immunotherapeutic Combination of Bifidobacterium infantis 35624 and Doxorubicin in Murine Breast Cancer.

The aim of the study is to investigate the anti-tumor effect of Bifidobacterium infantis 35624 in a xenograft model in BALB/c mice injected with 4T1 cells as a support for chemotherapeutic treatments of doxorubicin in vivo. The MTT assay was used to determine the cytotoxicity of doxorubicin against cancer cells, and apoptosis was analyzed by using flow cytometry. 4T1 cells (2 × 104 cells/mouse) were injected to BALB/c mice, and mice were fed with/without gavage B. infantis milk (108 CFU/mL) for 14 days and treated with doxorubicin on 5th and 10th days. The weights of the mice were recorded during the study, and the tumor sizes were measured by caliper at the 14th day. CD8 + T cell response was analyzed by using flow cytometer, and the results were compared to control and tumor control groups. The IC50 value for doxorubicin on 4T1 cell lines was determined as 0.053 ± 0.012 µg/mL. The apoptotic effect of doxorubicin at IC50 concentration was determined as 82.3% of cells to late apoptosis, 3.6% of cells to pro-apoptosis, and 6.2% of cells to necrosis. The treatment of doxorubicin, B. infantis milk, and the combination of them inhibited the tumor volumes by 55.50%, 40.69%, and 75.95%, respectively. B. infantis administration significantly enhanced the PHA-induced splenocyte proliferation (P < 0.05). It was shown that IFN-γ was effective in tumor growth and regression of metastasis. Consequently, the combination of B. infantis milk and doxorubicin showed the best anti-tumor effect.

Investigation of the supportive therapy potential of propolis extract and Lactobacillus acidophilus LA-5 milk combination against breast cancer in mice.

Immunotherapy has been applied in cancer treatments for many years as an alternative treatment method to radiotherapy, chemotherapy. It is well known that immunotherapy could suppress tumor formation by modulating the immune system of the host. The aim of the study is to investigate supportive therapy potential of acidophilus milk (AS) and propolis extract (PE) in the mouse xenograft breast cancer model. For this purpose, firstly cytotoxic effect of PE was determined by MTT assay against 4 T1 mouse breast cancer cells. Apoptotic effect of PE analyzed by flow cytometry. The antibacterial activity of PE was determined by the 96-well microplate broth-dilution method on Lactobacillus acidophilus LA-5. Then, Balb/c mice were injected subcutaneously with 4 T1 cells (2x105 cells/mouse) and also mice were given daily oral gavage with PE (66 mg/kg/day) and/or acidophilus milk (108 CFU/mL/mouse/day) for 14 days. The Balb/c mice were weighed throughout the study, and the tumor sizes were measured by caliper at the 14th day. The proliferation of splenocytes which collected spleen from mice was measured by MTT. CD8 + T cell response was analyzed by flow cytometry and results were evaluated in comparison with control and tumor control groups. The IC50 value for PE on 4 T1 cells was determined as 129.25 ± 1.90 µg/mL. The apoptotic effect of PE at IC50 concentration was determined as 3.3% of cells to late-apoptosis, 4.3% of cells to pro-apoptosis and 2.5% of cells to necrosis. The MIC and MBC values for PE on L. acidophilus LA-5 were 5000 ppm. The treatment of PE, AS and the combination of PE and AS were inhibited the tumor volumes by 59.16%, 28.29% and 63.39%, respectively. Acidophilus milk and PE combination significantly enhanced the ConA-, LPS- and PHA-induced splenocyte proliferation (P < 0.05). The acidophilus milk and PE combination were also found to stimulate IFN- γ production. In conclusion, the best anti-tumor effect was obtained by the combination of acidophilus milk and propolis.