TGF-β Receptor Inhibitor SB431542 Enhanced the Sensitivity of Gastric Cancer to 5-Fluorouracil: New Combined Targeted Therapy.

Gastric cancer (GC) continues to be a major cause of cancer-related deaths globally, primarily due to resistance to standard treatments like 5-fluorouracil (5FU). The transforming growth factor-β (TGF-β) signaling pathway is recognized as a key contributor to tumor progression and resistance to therapy. This work investigated the therapeutic potential of targeting TGF-β receptor I (TGFBR1) with the selective inhibitor SB431542 to enhance the effect of 5FU in GC. Analysis of public gene expression datasets revealed that increased levels of TGF-β and TGFBR1 are significantly connected with poor prognosis, particularly in high-grade GC. In vitro experiments using AGS and SNU-1 cell lines demonstrated that co-treatment with SB431542 and 5FU significantly reduced cell viability, making GC cells more sensitive to 5FU. This combination treatment led to a significant activation of caspase-dependent apoptosis, indicating an enhanced pro-apoptotic effect. These findings suggest that TGFBR1 inhibition could provide a strategic approach to reduce the dosage of 5FU, thereby minimizing its severe side effects in gastric cancer patients. Furthermore, these results underscore the potential of TGFBR1 as both a prognostic biomarker and a therapeutic target, warranting further investigation in aggressive forms of gastric cancer.