Development of a high-throughput screening platform for identification of functional BACH1 inhibitors reveals...

BACH1 is a transcriptional regulator that modulates various cytoprotective pathways. Among these pathways BACH1 regulates cellular oxidative stress responses by suppressing the expression of cytoprotective genes. Dysregulated BACH1 activity has been implicated in a range of pathologies, including chronic inflammatory diseases, fibrosis, and cancer, making it a promising therapeutic target. However, BACH1 remains an underexploited drug target, with limited pharmacological inhibitors available. We have developed a novel luciferase-based reporter cell line enabling quantitative, high-throughput assessment of BACH1 inhibition. Using this platform, we rigorously screened two small-molecule libraries with 2046 compounds and identified four structurally distinct compounds that robustly inhibit BACH1 function. Notably, these compounds also activate transcription factor NRF2, suggesting the potential for a broader modulation of oxidative stress pathways. Importantly, we demonstrate that commonly used 2D migration assays may fail to detect phenotypes consistent with BACH1 inhibition, resulting in false negatives. In contrast, we establish that 3D invasion assays more robustly capture anti-invasive effects of BACH1 functional inhibition. Using this 3D system, we validate the identified compounds as potent suppressors of lung cancer cell invasion in vitro. This study delivers a novel screening platform for BACH1-targeted drug discovery, and challenges current in vitro standards by establishing 3D invasion assays as a more accurate functional readout for BACH1-targeting compounds. Additionally, it identifies new dual functional BACH1 inhibitors/NRF2 activators, offering novel chemical scaffolds for the development of anti-metastatic therapies and potentially treatments for diseases driven by oxidative stress and inflammation.