Amsacrine (synonyms: m-AMSA, acridinyl anisidide) is an antineoplastic agent.

[1] Its planar fused ring system can intercalate into the DNA of tumor cells, thereby altering the major and minor groove proportions.

Amsacrine also expresses topoisomerase inhibitor activity, specifically inhibiting topoisomerase II.

[2] In contrast, the structurally similar o-AMSA differing in the position of the methoxy substituent group on the anilino-ring have little ability to poison topoisomerase II despite its intercalative behavior, suggesting that intercalation of the molecule in itself is insufficient to trap topoisomerase II as a covalent complex on DNA.

[3][4][5] This antineoplastic or immunomodulatory drug article is a stub.