Synthesis, Structural Modification, and Antismall Cell Lung Cancer Activity of 3-Arylisoquinolines with Dual Inhibitory Activity on Topoisomerase I and II

To overcome the compensatory effect between Topo I and II, one of the reasons accounting for the resistance of SCLC patients, we are pioneering the use of 3-arylisoquinolines to develop dual inhibitors of Topo I/II for the management of SCLC. A total of 46 new compounds were synthesized. Compounds 3g (IC₅₀ = 1.30 μM for NCI-H446 cells and 1.42 μM for NCI-H1048 cells) and 3x (IC₅₀ = 1.32 μM for NCI-H446 cells and 2.45 μM for NCI-H1048 cells) were selected for detailed pharmacological investigation, due to their outstanding cytotoxicity and dual Topo I and II inhibitory activity. 3g and 3x effectively prevent SCLC cell proliferation, invasion, and migration in vitro, byinducing mitochondrial apoptosis and inhibiting the PI3K/Akt/mTOR pathway. Their in vivo tumor inhibition rate is comparable to etoposide with lower toxicity. These results indicated their potential therapeutic values as dual Topo I and II inhibitors for treating SCLC.