Design and synthesis of the novel DNA topoisomerase II inhibitors: Esterification and amination substituted 4′-demethylepipodophyllotoxin derivates exhibiting anti-tumor activity by activating ATM/ATR signaling pathways

• Twelve novel 4′-demethylepipodophyllotoxin derivates had been synthesized.
• The compounds were evaluated for DNA topoisomerase II inhibitory activity.
• Most of compounds exhibited promising in vitro anti-tumor activity, e.g., Compound 1.
• Compound 1 induced BGC 823 apoptosis by activating ATM/ATR signaling pathways.

According to the structure–activity relationship, drug combination principle and bioisosterism, a series of the novel esterification and amination 4′-demethylepipodophyllotoxin derivates were rationally designed in order to discover the potential antitumor prodrug. And then these compounds were tested by the drug-topoisomerase II docking models for virtual screening. Thus, twelve target compounds were screened out and synthesized. Most of compounds exhibited promising in vitro anti-tumor activity, particularly 4-N-tris(hydroxymethyl)metylaminomethane-4-deoxy-4′-demethylepipodophyllotoxin (Compound 1). The anti-tumor activity of Compound 1 against the tumor cell lines BGC-823 (i.e., the IC50 value of 5.35 ± 0.77 μM), HeLa (i.e., the IC50 value of 160.48 ± 14.50 μM), and A549 (i.e., the IC50 value of 13.95 ± 5.41 μM) was significantly improved by 706%, 31% and 900% than that of etoposide (i.e., the IC50 values of 43.74 ± 5.13, 209.90 ± 13.42, and 139.54 ± 7.05 μM), respectively. Moreover, the IC50 value of Compound 1 against the normal human cell line HK-2 (i.e., 16.3 ± 3.77 μM) was 78% lower than that of etoposide (i.e., 9.17 ± 1.58 μM). Compound 1 could diminish the relaxation reaction topoisomerase II DNA decatenation at a concentration of 10 μM and induce BGC-823 apoptosis by breaking DNA double-strand and activating ATM/ATR signaling pathways.

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