Abstract 2507: Chronic stress promotes tumor progression and metastasis through the tumor microenvironment in triple-negative breast cancer

Abstract Background: Breast cancer is the most common cancer diagnosed in American women. Triple-negative breast cancer (TNBC) is three times more likely to end in death than other breast cancer subtypes and disproportionately affects young African American women. Chronic stress as a risk factor promotes tumor progression, but its role in TNBC progression and metastasis remains elusive. Methods: In this study, mice were implanted with 4T1-luciferase cells in the tibia or the fourth mammary pad of BALB/c mice and NSG mice. After four weeks of restraining inducing chronic stress and (or) β-adrenergic receptor inhibitor treatment, the impact of chronic stress on the progression and metastasis of tumor, tumor microenvironment was assessed. Results: Our results showed that chronic stress facilitated tumor progression and metastasis in both BALB/c mice and NSG TNBC mice models. In contrast, chronic stress reduced the number and function of tumor-infiltrating TCD8+ cells but increased the expression of the β2-adrenergic receptor of TCD8+ cells in the TNBC tumor microenvironment (TME) of BALB/c mice. Interestingly, chronic stress increased the density of neuron fiber in the TME of both BALB/c and NSG TNBC mice. Notably, the treatment of Propranolol (Prop, a β1- and β2-adrenergic receptor inhibitor) significantly decreased the tumor burden and metastasis of both BALB/c mice and NSG TNBC mice model. Accompany by recovering the function and number of TCD8+ cells in the TME of BALB/c mice. Conclusion: Our study indicates that chronic stress promotes TNBC progression and metastasis by regulating the tumor-immune network in the TME. Citation Format: Chao Zhang, Lizhong Wang, Runhua Liu. Chronic stress promotes tumor progression and metastasis through the tumor microenvironment in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2507.