Small molecule-mediated spatial targeting of mitochondria and the Golgi apparatus in cancer cells.

Cancer remains one of the most dynamic and complex diseases, driven by intricate interplay and cross-talk among various sub-cellular organelles. Among these, mitochondria and the Golgi apparatus (GA) have garnered significant attention due to their critical roles in diverse biological processes-many of which, when dysregulated, contribute to cancer development and progression. Despite this, the mechanistic understanding of mitochondria-GA cross-talk and their location-function relationships remains limited, largely due to the lack of chemical tools for spatial organelle-specific targeting. To bridge this gap, we designed and synthesized a concise library of protonated 3-methoxy-pyrrole-based small molecules featuring a positive charge. Screening this library in HeLa (cervical) and HCT-116 (colon) cancer cells identified a lead molecule, 7f, which self-assembled into nanoparticles and selectively localized to the mitochondria in HeLa cells, followed by mitochondrial impairment and generation of reactive oxygen species (ROS) leading to the induction of apoptosis by downregulating Bcl-2 and Cas-3 and upregulating BAX. Interestingly, a neutral phenylsulfonamide derivative (compound 9) of 7f rapidly localized to the GA within 30 minutes, triggered autophagy through the upregulation of Beclin and LC3-II/I and exhibited cytotoxicity when combined with the autophagy inhibitor chloroquine. These findings highlighted how subtle structural modifications can govern organelle-specific localization. We anticipate that these 3-methoxy-pyrrole-based small molecules represent promising chemical biology tools to dissect the spatial and functional dynamics of mitochondria-GA interplay, with potential implications for targeted cancer therapeutics.