Notch signaling in the tumor immune microenvironment of colorectal cancer: mechanisms and therapeutic opportunities.

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide, driven by a complex interplay of genetic, environmental, and immune-related factors. Among the pivotal pathways implicated in CRC tumorigenesis, the Notch signaling pathway is instrumental in governing cell fate decisions, tissue renewal, homeostasis, and immune cell development. As a highly conserved mechanism, Notch signaling not only modulates tumor cell behavior but also shapes the immune landscape within the tumor microenvironment (TME). Aberrant Notch signaling in CRC fosters immune evasion and tumor progression through its effects on the balance and functionality of immune cells, including myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs). Elevated Notch pathway activation correlates with advanced clinicopathological features and poorer clinical outcomes, highlighting its relevance as both a prognostic biomarker and a therapeutic target. Therapeutic approaches aimed at inhibiting the Notch pathway, such as γ-secretase inhibitors (GSIs) or monoclonal antibodies (mAbs) in combination with other therapies, have demonstrated promising efficacy in preclinical and clinical settings. This review examines the impact of Notch signaling on CRC immunity, elucidating its regulatory mechanisms within immune cells and its role in promoting tumor progression. Additionally, this review discusses therapeutic strategies targeting Notch signaling, including GSIs, mAbs, and potential combination therapies designed to overcome resistance and improve patient outcomes. By elucidating the multifaceted role of Notch within the CRC TME, this review underscores its potential as a target for innovative therapeutic strategies.