The Impact of Senescence-Associated Secretory Phenotype (SASP) on Head and Neck Cancers: From Biology to Therapy.

Cellular senescence is defined as a state of permanent cell cycle arrest, providing a natural barrier against cancer. However, senescent cells are very metabolically active and secrete a complex mixture of bioactive molecules collectively known as the senescence-associated secretory phenotype (SASP), which play a dual role in cancer biology. While the SASP can suppress tumors by facilitating immunosurveillance, it can also promote tumor progression by fostering a pro-inflammatory milieu, stimulating angiogenesis, enhancing invasiveness, and enabling immune evasion. In Head and Neck Cancers (HNCs), a highly heterogeneous group of malignancies, SASP has emerged as a critical player in disease progression and treatment resistance. Persistent DNA damage response (DDR) signaling drives SASP and thereby contributes to the progression of head and neck cancer by modulating the tumour microenvironment. It influences the tumor microenvironment (TME) by facilitating epithelial-to-mesenchymal transition (EMT), promoting cancer stem cell-like properties, and impairing the efficacy of radiotherapy, chemotherapy, and immune checkpoint inhibitors. These effects underscore the need for targeted interventions to regulate SASP activity. This review presents a comprehensive overview of the molecular mechanisms underlying SASP generation and its effects on HNCs. We discuss the dual roles of SASP in tumor suppression and progression, its contribution to therapy resistance, and emerging therapeutic strategies, including novel senolytic and senomorphic drugs. Finally, we highlight key challenges and future directions for translating SASP-targeted therapies into clinical practice, emphasizing the need for biomarker discovery, and a deeper understanding of SASP heterogeneity. By targeting the SASP, there is potential to enhance therapeutic outcomes and improve the management of HNCs.