Cold exposure enhances doxorubicin antitumor efficacy and suppresses oncogenic signalling in a 4T1 mammary tumor mouse model.

BACKGROUND

Cold exposure (CE) is emerging as a sustainable adjunct to cancer therapy by modulating metabolism and immunity. This study evaluated the effect of cold-water swimming alone or combined with Doxorubicin on tumor progression, immune response, and molecular markers in a 4T1 breast cancer mouse model.

METHODS

Female BALB/c mice were allocated into 10 groups, including untreated tumor controls, cold exposure regimens (pre- and/or post-induction), Doxorubicin (Dox) alone, and combined CE + Doxorubicin. Tumor growth was assessed by caliper and ultrasound imaging. Serum cytokines (IL-2, IL-6, TNF-α, IFN-γ) were quantified by ELISA. Gene expression of angiogenesis (VEGF), proliferation (CCND1), invasion (MMP), EMT (CDH1), oncogenes (HER2, MYC), apoptosis (P53, Bax), and STAT3 was analyzed by qPCR. Histology confirmed tissue changes.

RESULTS

CE improved tumor regression without affecting body weight, food intake, or activity. Tumor-free rates were 60 % in CE groups and 70 % in CE + Dox groups versus 0 % in controls. Ultrasound detected early regression and vascular loss in combination groups. CE + Dox synergistically enhanced IL-2 and IFN-γ (up to 102.5 pg/mL) while reducing IL-6 and TNF-α. Gene expression showed marked downregulation of VEGF, HER2, MYC, MMP, CCND1, and STAT3, with preserved CDH1. Combined therapy produced the most favorable molecular and histological profiles.

CONCLUSION

CE, particularly with Dox, enhances antitumor immunity, suppresses angiogenesis and invasion, and reduces inflammation, offering a simple, cost-effective adjunct to chemotherapy. These findings support further investigation of CE as a clinically relevant, non-pharmacologic strategy for breast cancer treatment.