An adverse outcome pathway for DNA adduct formation leading to kidney failure.

An Adverse Outcome Pathway (AOP) is a conceptual framework in toxicology and risk assessment that outlines the series of events from a chemical's molecular interaction to the resulting adverse health effect. This framework offers a structured approach to organizing biological knowledge, making it especially useful for understanding the mechanisms through which chemicals cause harm. Following a comprehensive analysis of the literature, an AOP was elucidated for key events linking DNA adduct formation, caused by compounds such as platinum anticancer drugs, to tubular necrosis, resulting in kidney failure. Currently, cisplatin, carboplatin and oxaliplatin are the three most utilised Pt-based drugs used globally for the treatment of cancer. The hydrolysis of platinum anticancer agents post-cellular uptake yields electrophilic intermediates that covalently bind to nucleophilic sites on DNA to form adducts that represent the molecular initiating event. When DNA repair mechanisms become unbalanced, the nephrotoxic response following the formation of DNA adducts leads to DNA damage and mitochondrial dysfunction. These events promote the generation and release of reaction oxygen species (ROS) to induce oxidative stress, causing cell death and inflammation. Upon detachment from the basement membrane, these compromised cells are subsequently deposited in the tubular lumen. Tubular obstruction and inflammatory responses to proximal tubule insult can lead to secondary toxicity and tubular necrosis, further exacerbating kidney injury and precipitating a progressive decline of renal function, finally resulting in kidney failure.