A Three-agent Regimen for Triple Negative Breast Cancer Treatment.

Background: Triple-negative breast cancer (TNBC) has a poor prognosis with current treatment options. Novel therapeutic strategies are urgently needed to enhance treatment outcomes for TNBC.

Objective: This study evaluated the efficacy of a three-agent regimen compared to existing treatment regimens in a TNBC mouse model, and elucidated its potential mechanisms of action.

Methods: The TNBC xenograft tumor mouse model was established using a 4T1 cell line in female BALB/c mice. Mice were treated with the three-agent regimen and other comparative treatments. Tumor volume was monitored to assess the anti-tumor effects. Biochemical and pathological evaluations were conducted to examine the impact of the regimen on anti-tumor immunity, anti- tumor angiogenesis, and tumor cell apoptosis.

Results: The three-agent regimen consisting of SIN+BEV+PAB demonstrated significant anti-tumor efficacy compared to controls, PAB alone, SIN+PAB, and BEV+PAB groups from day 9 of drug administration. The superior anti-tumor effect of SIN+BEV+PAB was primarily attributed to enhanced anti-tumor immunity, evidenced by increased percentages of CD4+ and CD8+ T cells, elevated IFN-γ levels, and decreased percentages of Tregs, reduced levels of TGF-β, IL-6, and IL-10. Additionally, the regimen showed potent anti-angiogenic effects by reducing VEGF expression and micro vessel density (MVD). Furthermore, it promoted tumor cell apoptosis through upregulation of BAX and cleaved caspase3, while downregulating Bcl2.

Conclusion: These findings suggest that the novel three-agent combination of SIN+BEV+PAB may prove beneficial in improving treatment outcomes for patients with TNBC. The development of this regimen, which may be eligible for patent protection, could facilitate its introduction as a new therapeutic option for advanced TNBC in clinical practice.