Leveraging Morphological Profiling for Mechanistic Elucidation of Metal-Based Anticancer Compounds

Development of novel metallotherapeutics poses both significant potential and numerous challenges due to their complex reactivity in physiological systems and the ambiguity of molecular targets. Advances in target-agnostic and phenotypic-based drug profiling approaches have yielded success in anticancer therapeutic development, but their application to the development and discovery of metal-based drug candidates has been limited. This study demonstrates the use of morphological profiling on a diverse library of metal-containing compounds to elucidate mechanisms of action, providing new insights into the activities of established chemotherapeutics and guiding downstream studies of select novel compounds in the absence of predefined molecular targets. The validity of this strategy was established using a subset of clinically approved anticancer therapeutics, where morphological profiling discerned the mechanistic differences among oxaliplatin, cisplatin, carboplatin, and the clinical-stage ruthenium-based compound BOLD-100. Subsequently, a combination of cytotoxicity and selectivity assessments in conjunction with an analysis of morphological profiles of the compound library identified a novel ruthenium 2-(2-pyridyl)benzimidazole-based compound series, which induced changes in the mitochondrial morphology of cancer cells. This association was investigated further, revealing an accompanying increase in levels of mitochondrial reactive oxygen species and a corresponding depolarization of the mitochondrial membrane. This application of morphological profiling will enable the rapid identification of promising metal-containing therapeutics, aiding in rational development strategies and mitigating persistent challenges in metallotherapeutic development.