Triterpenoids from quinoa bran exert anti-colorectal cancer effects via oxidative stress-mediated apoptosis and immune reactivation

Abstract

Quinoa (Chenopodium quinoa Willd.) is globally recognized as a “superfood” with superior nutritional value. Quinoa bran, the nutrient-dense outer layer of the grain, is increasingly utilized as a high-value ingredient in the food industry. Epidemiological evidence has linked the consumption of whole grains to a reduced risk of colorectal cancer (CRC). Our previous studies have confirmed that triterpenoids enriched in quinoa bran (QBT) exhibit significant anti-CRC activity, yet the underlying molecular mechanisms remain unclear. In this study, we demonstrate that QBT exerts potent tumor-suppressive effects in vitro and in vivo without inducing toxicity in major murine organs, indicating a favorable safety profile. Mechanistically, QBT acts as an apoptosis inducer by triggering lethal reactive oxygen species (ROS) accumulation in CRC cells, resulting in mitochondrial dysfunction and caspase-dependent apoptosis. Concurrently, QBT functions as an immunosensitizer by activating endoplasmic reticulum stress, thereby converting oxidative cell death into immunogenic cell death (ICD), as evidenced by enhanced calreticulin exposure and the release of ATP and high mobility group box 1 (HMGB1), eliciting a robust “vaccine-like effect”. Consequently, QBT effectively promotes dendritic cell maturation and CD8⁺ T cell infiltration. Collectively, this study reveals that QBT suppresses CRC through a dual mechanism involving direct apoptosis induction and immune activation via ICD. These results support QBT as a promising functional food ingredient for the prevention and adjuvant treatment of CRC.