Hypoxia-mediated changes in bone marrow microenvironment in breast cancer dormancy

Area of Science:

• Oncology
• Stem Cell Biology
• Cancer Metastasis

Background:

• Breast cancer (BC) poses a clinical challenge due to dormant cancer cells (BCCs) in the bone marrow (BM), leading to potential late-stage metastasis.
• Dormant BCCs exhibit characteristics of cancer stem cells (CSCs), supported by the BM niche and its secretome.
• Limited research exists on how the hypoxic BM environment influences BCC dormancy and behavior, particularly concerning age-related differences in oxygen levels.

Purpose of the Study:

• To comprehensively review the influence of the hypoxic bone marrow environment on breast cancer cell dormancy and behavior.
• To explore the role of vascularity within different BM regions on BCC dormancy and CSC characteristics.
• To investigate the impact of hypoxia-inducible factor 1 alpha (HIF1-α) and epigenetic mechanisms on BC progression and treatment resistance in aging BM.

Main Methods:

• Literature review focusing on the interplay between bone marrow vascularity, hypoxia, and breast cancer cell dormancy.
• Analysis of existing data on the role of HIF1-α in regulating gene networks involved in BC cell metabolism, survival, invasion, and angiogenesis.
• Examination of epigenetic mechanisms contributing to hypoxic responses during cancer dormancy in the bone marrow.

Main Results:

• The hypoxic BM niche supports BCC dormancy, promoting CSC phenotypes.
• HIF1-α acts as a key mediator under hypoxia, influencing gene expression related to tumor progression, heterogeneity, and treatment resistance.
• Epigenetic modifications play a role in hypoxic responses during BC dormancy in the BM.

Conclusions:

• The hypoxic BM environment significantly impacts BC cell dormancy, CSC behavior, and therapeutic resistance.
• HIF1-α emerges as a potential therapeutic target for overcoming dormancy and treatment resistance in breast cancer.
• Understanding age-related changes in BM hypoxia and vascularity is crucial for predicting BC outcomes in different age groups.