Hypoxic Memory Mediates Prolonged Tumor-Intrinsic Type I Interferon Suppression to Promote Breast Cancer Progression

Area of Science:

• Oncology
• Immunology
• Cell Biology

Background:

• Hypoxia, common in solid tumors, drives progression and metastasis, primarily via hypoxia-inducible factors (HIF).
• Understanding long-term hypoxia effects beyond immediate HIF responses is crucial for targeting metastasis.

Purpose of the Study:

• To uncover a hypoxia-induced mechanism with prolonged effects on metastasis.
• To investigate the role of cellular memory in hypoxia-driven tumor progression.

Main Methods:

• Examined hypoxia effects on type I IFN signaling and antigen presentation in breast cancer cell lines.
• Investigated HIF-dependent and independent pathways.
• Assessed the persistence of hypoxia-induced changes and the impact of interventions like IRF3 overexpression and entinostat.

Main Results:

• Hypoxia downregulated type I IFN signaling and antigen presentation in luminal breast cancer cells.
• A durable "hypoxic memory" phenotype was observed, with suppressed IFN/AP persisting post-hypoxia.
• Cells with hypoxic memory showed increased tumorigenesis and metastasis.
• Entinostat erased this memory, restoring IFN targets.

Conclusions:

• Hypoxia establishes a long-lasting cellular memory that suppresses anti-tumor immunity (IFN/AP).
• This memory phenotype enhances breast cancer cell tumorigenesis and metastatic potential.
• Targeting this memory, e.g., with entinostat, may offer strategies against metastasis.