Calicheamicins

Calicheamicins are enediyne natural products that bind the DNA minor groove and induce double-strand DNA breaks, making them potent DNA-damaging agents for cancer research^[1]. Mechanistically, their activity supports antibody-drug conjugate design because unconjugated calicheamicin shows non-discriminatory cytotoxicity toward cancer and healthy cells^[2]. In leukemia and lymphoma models, calicheamicin derivatives have been delivered through CD33-targeted gemtuzumab ozogamicin and CD22-targeted inotuzumab ozogamicin, linking DNA cleavage to antigen-directed cytotoxicity^[2][3]. Compared with microtubule-disrupting ADC payload classes such as maytansinoids and auristatins, calicheamicin functions as a DNA-targeting antibiotic payload rather than a tubulin inhibitor^[4]. For experimental applications, linker chemistry and site-specific conjugation directly affect aggregation, circulation stability, and tolerability of calicheamicin ADCs^[5]. Resistance studies further identify DNA damage sensing, TP53, MDM2, and ATM as modulators of calicheamicin sensitivity in acute leukemia cells^[6].