This study provides a novel strategy for precision therapy of mCRPC by specifically blocking the proteolytic cleavage of TGFBR1, thereby inhibiting tumor progression while preserving the physiological functions of TGF-β. This offers a direct solution to overcome the toxicity issues associated with current TGF-β-targeted therapies.
Literature Overview
The article titled 'Targeting oncogenic TβRI signaling inhibits androgen-independent prostate cancer growth and metastasis,' published in Signal Transduction and Targeted Therapy, systematically investigates the oncogenic role of aberrant splicing of the TβRI receptor in the TGF-β signaling pathway in metastatic castration-resistant prostate cancer (mCRPC), and develops a specific monoclonal antibody to block this process. By integrating clinical data, cellular models, and animal experiments, the study reveals the central role of the TGFBR1-ADAM17-TβRI-ICD-p300 signaling axis in tumor invasion and metastasis. Furthermore, it demonstrates that this strategy effectively suppresses tumor progression while preserving normal TGF-β physiological functions, offering a highly selective therapeutic approach for mCRPC.Background Knowledge
Metastatic castration-resistant prostate cancer (mCRPC) is the primary cause of prostate cancer mortality, with treatment limited by enhanced tumor invasiveness, metastatic potential, and resistance to existing therapies. TGF-β1 acts as a tumor suppressor in early stages but switches to an oncogenic role in advanced cancers, driving epithelial-mesenchymal transition (EMT), invasion, and immune suppression. However, traditional small-molecule kinase inhibitors targeting TGF-β1 or its receptor TGFBR1 disrupt essential physiological functions in the heart and aorta, leading to severe cardiovascular toxicity that limits clinical application. Therefore, selectively inhibiting the oncogenic signals of TGF-β1 without affecting its homeostatic functions remains a major challenge. This study identifies a key mechanism: in cancer cells, the TGFBR1 receptor is cleaved by the protease ADAM17, generating a nuclear-localizing TβRI-ICD fragment. This fragment binds to the transcriptional co-activator p300, driving expression of EMT-related genes such as SNAI1, forming a positive feedback loop that promotes tumor progression. This non-canonical pathway provides an ideal target for 'precision inhibition of oncogenic signaling.'
Research Methods and Experiments
The study analyzed multiple clinical cohorts (SU2C, RMH) to investigate the relationship between TGFBR1 expression and prognosis in mCRPC patients, validating the positive correlation between TGFBR1 and ADAM17 using RNA-seq data. In vitro, using prostate cancer cell lines such as PC-3U and VCaP, a fully human monoclonal antibody, mAbF11, was developed via phage display technology followed by affinity maturation. This antibody specifically binds to the ADAM17 cleavage site on TGFBR1, blocking the generation of TβRI-ICD. Its inhibitory effect on the non-canonical TGF-β1 signaling pathway was confirmed using co-IP, immunofluorescence, and qRT-PCR. In vivo, a human xenograft mCRPC mouse model was established to evaluate the impact of mAbF11 on primary tumor growth, lymph node metastasis, and EMT markers. Additionally, in situ PLA was used to directly visualize the nuclear complex of TβRI-ICD and p300 in tumor tissues, providing mechanistic evidence. Efficacy and safety were compared head-to-head with the standard chemotherapy agent docetaxel.Key Conclusions and Perspectives
Research Significance and Prospects
This study introduces a new paradigm for drug development—'functional selectivity' in inhibiting TGF-β signaling—by targeting receptor cleavage rather than kinase activity, enabling tumor-specific suppression. This approach could resolve long-standing toxicity challenges and advance next-generation TGF-β pathway inhibitors into clinical trials. For clinical monitoring, co-expression of TGFBR1 and ADAM17 may serve as a predictive biomarker for aggressive progression in mCRPC, guiding personalized therapy. In disease modeling, the study emphasizes the importance of evaluating cardiovascular effects in animal models to more accurately predict clinical safety.
Conclusion
This study uncovers a key mechanism by which proteolytic cleavage of TGFBR1 drives mCRPC progression and develops a high-affinity, fully human antibody, mAbF11, enabling precise blockade of oncogenic signaling. This strategy effectively suppresses tumor growth and metastasis while preserving TGF-β physiological functions and exhibits no significant toxicity, demonstrating a safety advantage over current chemotherapy. From bench to bedside, this discovery offers new therapeutic hope for mCRPC patients, marking a transition from 'broad-spectrum inhibition' to 'precision intervention' in TGF-β-targeted therapies. The pan-cancer potential of this antibody further positions it as a universal therapeutic candidate for multiple aggressive cancers, potentially reshaping the standard of care and serving as a cornerstone for future combination immunotherapies or targeted treatments.
