Marine natural product-inspired 2-(3,4,5-trimethoxybenzoyl)quinazolin-4(3H)-one derivative CHNQD-01522: A novel anti-hepatocellular carcinoma agent targeting colchicine binding site of microtubule.

Microtubule targeting agents are effective in cancer therapy, but current inhibitors face challenges including systemic toxicity and P-glycoprotein (P-gp) mediated drug resistance, underscoring the need for novel microtubule inhibitors. Quinazolin-4(3H)-one alkaloids, with diverse targets, exhibit significant potential for developing novel anti-cancer agents. Herein, inspired by marine quinazolin-4(3H)-one alkaloid penipanoid C, compounds 1‒55, a series of 2-(3,4,5-trimethoxybenzoyl)quinazolin-4(3H)-one derivatives were synthesized and identified. Among them, CHNQD-01522 (18) exhibited the strongest cytotoxic activity against Huh-7 and HepG2 cell lines with IC50 values of 0.19 and 0.17 μM. Meanwhile, treatment with CHNQD-01522 (18) suppressed tumor cell colony formation, arrested cell cycle in G2/M phases, and induced apoptosis. Mechanistic studies revealed that it is a novel microtubule inhibitor targeting the colchicine binding site, which cannot be transported by P-gp in cancer cells. Encouragingly, CHNQD-01522 (18) showed significant in vivo anti-tumor efficacy in the subcutaneous xenograft tumor model (TID, TGI = 79.09%) with frequency dependence. More importantly, the anti-tumor efficacy was also verified in an orthotopic xenograft tumor model. Furthermore, CHNQD-01522 (18) displayed satisfactory safety profiles in preliminary toxicity studies. Taken together, this study has identified a novel microtubule inhibitor with significant anti-hepatocellular carcinoma (HCC) activity, inherent resistance-avoidance property, and a favorable safety profile, showing promise as an HCC therapeutic.