Nrf2: A key regulator in chemoradiotherapy resistance of osteosarcoma.

Osteosarcoma (OS), frequently observed in children and adolescents, is one of the most common primary malignant tumors of the bone known to be associated with a high capacity for invasion and metastasis. The incidence of osteosarcoma in children and adolescents is growing annually, although improvements in survival remain limited. With the clinical application of neoadjuvant chemotherapy, chemotherapy combined with limb-preserving surgery has gained momentum as a major intervention. However, certain patients with OS experience treatment failure owing to chemoradiotherapy resistance or metastasis. Nuclear factor E2-related factor 2 (Nrf2), a key antioxidant factor in organisms, plays a crucial role in maintaining cellular physiological homeostasis; however, its overactivation in cancer cells restricts reactive oxygen species production, promotes DNA repair and drug efflux, and ultimately leads to chemoradiotherapy resistance. Recent studies have also identified the functions of Nrf2 beyond its antioxidative function, including the promotion of proliferation, metastasis, and regulation of metabolism. The current review describes the multiple mechanisms of chemoradiotherapy resistance in OS and the substantial role of Nrf2 in the signaling regulatory network to elucidate the function of Nrf2 in promoting OS chemoradiotherapy resistance and formulating relevant therapeutic strategies.