Synergistic effects of Ω-3 polyunsaturated fatty acid supplementation and programmed cell death protein 1 blockade on tumor growth and immune modulation in a xenograft model of esophageal cancer

Abstract

Esophageal cancer, especially esophageal squamous cell carcinoma (ESCC), remains a significant global health challenge with limited survival rates. This study aimed to elucidate the combined effects of immune-modulating nutrition (IMN) with Ω-3 polyunsaturated fatty acid (PUFA) supplementation and anti-programmed cell death protein 1 (PD-1) treatment on tumor growth and immune responses in a xenograft model of ESCC. A total of 36 C57BL/6 mice were used to construct a xenograft model using the mouse esophageal cancer cell line AKR. Mice were subjected to treatment with anti- PD-1 antibody combined with either Ω-3 PUFA-rich or Ω-3 PUFA-deficient nutrition. Tumor growth, immune markers, cytokine profiles, and metabolic changes were evaluated. The combination of anti-PD-1 and Ω-3 PUFA supplementation significantly inhibited tumor growth more effectively than anti-PD-1 treatment alone. Enhanced expression of immune markers PD-L1 and CD3 was observed in Ω-3 PUFA-fed mice. Additionally, compared with anti-PD-1 therapy and anti-PD-1 plus Ω-3 PUFA-deficient nutrition, Ω-3 PUFAs intensified alterations in key chemokines and cytokines, including elevated IL-12, IFN-γ, and GM-CSF levels, and reduced CXCL12 levels. However, Ω-3 PUFAs did not significantly alter the glycolysis and tryptophan metabolic program induced by anti-PD-1. Our findings indicated the potential synergetic therapeutic benefits of combining anti-PD-1 treatment with Ω-3 PUFA supplementation in ESCC, which offered promising avenue for further research.