FOSL1

FOSL1 (FOS-like antigen 1), also known as FRA1, is a member of the AP-1 transcription factor family formed through dimerization with JUN proteins. It regulates cellular processes including proliferation, differentiation, and apoptosis by binding to target gene promoters. FOSL1 modulates extracellular matrix remodeling through MMPs (matrix metalloproteinases) and drives epithelial-mesenchymal transition (EMT) via SNAIL/SLUG activation. Key pathways involving FOSL1 include MAPK/ERK, JNK, and TGF-β signaling. Overexpression of FOSL1 is implicated in tumor progression, metastasis, and therapy resistance across multiple cancers, particularly breast, lung, and colorectal carcinomas. It also contributes to fibrotic diseases and chronic inflammation. While no direct FOSL1-targeted drugs are clinically available, preclinical studies explore inhibitors of upstream regulators (MEK/JNK inhibitors) and gene-silencing approaches. Recent efforts focus on disrupting FOSL1-JUN interactions or its cooperation with β-catenin in Wnt-driven malignancies.