Liquid Chromatography-Mass Spectrometry Screening of Cyclophosphamide DNA Damage In Vitro and in Patients Undergoing Chemotherapy Treatment

DNA alkylating drugs have been used as frontline medicationstotreat cancer for decades. Their chemical reaction with DNA leads tothe blockage of DNA replication, which impacts cell replication. Whilethis impacts rapidly dividing cancerous cells, this process is notselective and results in highly variable and often severe side effectsin patients undergoing alkylating-drug based therapies. The developmentof biomarkers to identify patients who effectively respond with tolerabletoxicities vs patients who develop serious side effects is needed.Cyclophosphamide (CPA) is a commonly used chemotherapeutic drug andlacks biomarkers to evaluate its therapeutic effect and toxicity.Upon administration, CPA is metabolically activated and convertedto phosphoramide mustard and acrolein, which are responsible for itsefficacy and toxicity, respectively. Previous studies have exploredthe detection of the major DNA adduct of CPA, the interstrand DNA-DNAcross-link G-NOR-G, finding differences in the cross-link amount betweenFanconi Anemia and non-Fanconi Anemia patients undergoing chemotherapytreatment. In this study, we take advantage of our DNA adductomicapproach to comprehensively profile CPA's and its metabolites' reactions with DNA in vitro and in patients undergoingCPA-based chemotherapy. This investigation led to the detection of40 DNA adducts in vitro and 20 DNA adducts in patientstreated with CPA. Moreover, acrolein-derived DNA adducts were quantifiedin patient samples. The results suggest that CPA-DNA damage is verycomplex, and an evaluation of DNA adduct profiles is necessary whenevaluating the relationship between CPA-DNA damage and patient outcome.