Abstract

Myoglobin (Mb), traditionally known for its role in oxygen storage and transport in muscle tissue, has recently been identified in various non-muscle tumor cells, suggesting a novel role in cancer biology. This study investigates the expression of Mb in different tumor cell lines and clinical samples, and elucidates its functional significance in the progression of malignancy, particularly focusing on cellular metabolism and redox homeostasis. Using immunohistochemistry, Western blotting, and quantitative PCR, we confirmed Mb expression across a panel of human carcinoma cells. Functional assays, including oxygen consumption rate measurements and reactive oxygen species (ROS) analysis, revealed that Mb expression enhances the cells' ability to cope with hypoxic tumor microenvironments, primarily by acting as an oxygen buffer and a potent ROS scavenger. Furthermore, genetic manipulation of Mb levels demonstrated a correlation between increased Mb expression and altered mitochondrial dynamics, leading to reduced cell proliferation, migration, and invasion in vitro. These findings suggest that Mb expression in tumor cells is a complex, context-dependent phenomenon that may serve as a prognostic marker. The study proposes that Mb's ability to modulate cellular bioenergetics and oxidative stress pathways represents a critical mechanism by which tumor cells adapt to the harsh tumor environment, offering a potential new target for therapeutic intervention in malignancy.