Metformin Boosts Doxorubicin Efficacy and Increases CD8 + T Cell Frequency in Mouse Breast Cancer

Purpose: Breast cancer is a leading cause of cancer-related deaths among women worldwide. The presence and function of CD8 + T cells in the tumor microenvironment have been associated with better patient outcomes. Drug toxicity has posed a significant challenge to the clinical implementation of chemotherapy-based strategies in cancer treatment.

Methods: In this study, we employed flow cytometry to investigate the potential synergistic immunomodulatory effects on CD8 + T cells in a mouse model of breast cancer by combining metformin, an anti-diabetic medication, with doxorubicin.

Results: Through flow cytometry analysis, we observed that the combination of the two drugs led to an increased percentage of CD8 + T cells compared to either drug alone. The modulation of HIF-1α and  STAT3 gene expression in the combination group further confirmed the efficacy of this approach.

Conclusions: Our findings suggest that combining metformin with doxorubicin can enhance the anticancer activity of doxorubicin and decrease its cytotoxicity in a 4T1 breast cancer mouse model.