Antioxidant Activity during Tumor Progression: A Necessity for the Survival of Cancer Cells?

Abstract

Antioxidant defenses encompass a variety of distinct compounds and enzymes that are linked together through their capacity to neutralize and scavenge reactive oxygen species (ROS). While the relationship between ROS and tumorigenesis is clearly complex and context dependent, a number of recent studies have suggested that neutralizing ROS can facilitate tumor progression and metastasis in multiple cancer types through distinct mechanisms. These studies therefore infer that antioxidant activity may be necessary to support the viability and/or the invasive capacity of cancer cells during tumor progression and metastasis. Here, we discuss some of the accumulating evidence suggesting a role for antioxidant activity in facilitating tumor progression.

Keywords: NADPH; Nrf2; antioxidant; extracellular matrix; metastasis; pentose phosphate pathway; reactive oxygen species.

Figure 1

Mechanisms of antioxidant generation during cancer development. A wide variety of endogenous antioxidant pathways exist within cells which mitigate oxidative stress to enhance cell survival. The above pathways are paramount to augment survival in the absence of matrix attachment, tumor progression, and metastatic dissemination. All protein structures were retrieved from the RSCB Protein Data Bank [30] and compounds were retrieved from PubChem Compound.