DNA integrity and repair pathways (DDR)

DNA integrity and repair pathways represent the collective cellular machinery responsible for maintaining genomic stability against endogenous and exogenous threats (Nature Reviews Cancer, 2004). When cells are exposed to a combination of etoposide and mitomycin C, they face a dual assault: etoposide stabilizes covalent complexes of topoisomerase II and DNA, leading to double-strand breaks (DSBs) (PubChem CID 36462), while mitomycin C functions as a potent alkylating agent that creates interstrand cross-links (ICLs) (PubChem CID 5746). These lesions require distinct yet overlapping repair systems, including the Fanconi Anemia (FA) pathway, Nucleotide Excision Repair (NER), and Homologous Recombination (HR) (PubMed PMID: 11029558). In a clinical or research context, targeting these pathways with such a combination is often intended to induce catastrophic DNA damage and apoptosis in malignant cells. However, the complexity of these pathways means that resistance can emerge through the upregulation of specific repair proteins, making them a focus for therapeutic modulation and biomarker discovery (StatPearls, 2023).

Other names

DNA damage responseDNA repair mechanismsGenome maintenance pathways

Etoposide acts by inhibiting topoisomerase II, leading to the accumulation of double-strand breaks, while mitomycin C acts as a DNA alkylating agent that forms lethal interstrand cross-links; together, they synergistically overwhelm cellular repair machinery such as homologous recombination and the Fanconi anemia pathway (PubChem CID 36462, 5746).