LFZ-4-46, a tetrahydroisoquinoline derivative, induces apoptosis and cell cycle arrest via induction of DNA damage and activation of MAPKs pathway in cancer cells

LFZ-4-46, that is [2-hydroxy-1-phenyl-1,5,6,10b-tetrahydropyrazolo(5,1-a) isoquinolin-3(2H)-yl](phenyl) methanone, a tetrahydroisoquinoline derivative with a pyrazolidine moiety, was synthetically prepared. The anti-cancer mechanism of the compound has not been clarified yet. In this study, the anticancer effects and potential mechanisms of LFZ-4-46 on human breast and prostate cancer cells were explored. (a) 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazoliumbromide assay was first performed to detect the effects of LFZ-4-46 on the viability of human cancer cells. (b) Comet assay was utilized to evaluate DNA damage. (c) Cell cycle, apoptosis and mitochondrial membrane potential were detected by flow cytometry. (d) The expression of relative proteins was detected by western blotting assay. LFZ-4-46 significantly inhibited the viability of cancer cells in a time- and dose-dependent manner and had no obviously inhibitory effect on the viability of mammary epithelial MCF-10A cells. Mechanistic studies demonstrated that LFZ-4-46-induced cell apoptosis and cycle arrest were mediated by DNA damage. It caused DNA damage through activating γ-H2AX and breaking DNA strands. Further studies showed that mitogen-activated protein kinasess pathway was involved in these activated several key molecular events. Finally, LFZ-4-46 showed a potent antitumor effect in vivo. These results suggest that LFZ-4-46 may be a potential lead compound for the treatment of breast and prostate cancer.