Researchers have unveiled the intricate molecular mechanisms governing TCF/LEF-mediated transcription in the canonical Wnt pathway, identifying these proteins as promising therapeutic targets for cancer and fibrotic diseases. The review, published in Current Molecular Pharmacology, systematically dissects how four mammalian TCF/LEF paralogs—TCF7, LEF1, TCF7L1, and TCF7L2—achieve functional specificity through modular domain architecture and extensive alternative splicing.
"TCF/LEF proteins function as the final integrators of Wnt signals, converting β-catenin activation into precise transcriptional outputs," explained co-author Yusuke Higuchi from Beckman Research Institute. "Their regulation involves a complex interplay of co-repressors, chromatin remodelers, and post-translational modifications that we've only recently begun to understand in detail."
The study reveals that Wnt enhanceosome components remain pre-assembled in a poised configuration even in the absence of signaling, enabling rapid response upon β-catenin nuclear translocation. Key regulatory mechanisms include TLE co-repressor clearance via UBR5-mediated ubiquitination, context-dependent TCF isoform switching, and phosphorylation by kinases such as TNIK and HIPK2.
Most significantly, the review documents the clinical translation of these findings. The TNIK inhibitor INS018_055, identified through artificial intelligence-driven drug discovery, successfully completed Phase II trials in idiopathic pulmonary fibrosis (IPF), demonstrating reduced lung function decline over 52 weeks. "This represents the first robust clinical validation that targeting TCF/LEF regulatory kinases can safely modulate Wnt signaling in humans," Higuchi noted.
While challenges remain in developing direct TCF/LEF binders due to their intrinsically disordered β-catenin binding domains, emerging PROTAC and AI-designed protein technologies offer new avenues. The study underscores the potential for selective TCF/LEF modulation to treat diverse diseases while avoiding toxicity associated with upstream Wnt inhibition.
