ATC Group: L01CB Podophyllotoxin derivatives

The main effect of etoposide appears to be at the late S and early G₂ portion of the cell cycle in mammalian cells. The predominant macromolecular effect of etoposide seems to be the rupture of the double strand by an interaction with DNA-topoisomerase II or by the formation of free radicals. Etoposide has been shown to cause metaphase arrest in chick fibroblasts.

Podophyllotoxin is a metaphase inhibitor in dividing cells binding to at least one binding site on tubulin. Binding prevents tubulin polymerisation required for microtubule assembly. At higher concentrations, podophyllotoxin also inhibits nucleoside transport through the cell membrane.

Teniposide is a phase-specific cytotoxic drug, acting in the late S or early G₂ phase of the cell cycle, thus preventing cells from entering mitosis. Teniposide has a broad spectrum of in vivo antitumor activity against murine tumors, including hematologic malignancies and various solid tumors.