TGF-β Signaling in Cancer: Mechanisms of Progression and Therapeutic Targets

Transforming growth factor-β (TGF-β) is a key protein family member that includes activins, inhibins, and bone morphogenetic proteins (BMPs). It is essential in numerous biological processes, such as chemotaxis, apoptosis, differentiation, growth, and cell migration. TGF-β receptors initiate signaling through two primary pathways: the canonical pathway involving Smad proteins and non-canonical pathways that utilize alternative signaling mechanisms. When TGF-β signaling is disrupted, it has been shown to contribute to the development of various diseases, including cancer. Initially, TGF-β effectively inhibits the cell cycle and promotes apoptosis. However, its role can transition to facilitating tumor growth and metastasis as the disease progresses. Moreover, TGF-β drives cancer progression through epithelial–mesenchymal transition (EMT), modulation of factor expression, and evasion of immune responses. This complexity establishes the need for further research, particularly into pharmacological agents targeting TGF-β, which are emerging as promising therapeutic options. Current clinical and preclinical studies are making significant strides toward mitigating the adverse effects of TGF-β. This underscores the critical importance of understanding its underlying mechanisms to enhance treatment effectiveness and improve survival rates for cancer patients.