Discovery of an orally active and liver-targeted dual prodrug of 5-fluoro-2′-deoxyuridine-5′-monophosphate for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths globally. Hepatic arterial infusion chemotherapy with 5-fluorouracil (5-FU) have been considered; however, it has limited survival benefits because of unbearable toxicity. Hence, a series of 5-fluoro-2′-deoxyuridine-5′-monophosphate (FdUMP) prodrugs was designed and synthesized using ProTide technology. By favorable membrane permeability and bypassing enzymatic activation pathway of 5-FU to FdUMP, DL series of ProTide prodrugs circumvented mechanisms of 5-FU resistance and avoided the generation of associated toxic catabolites, resulting in enhanced anti-HCC efficacy and weak toxicity. Antiproliferative activity of compounds was evaluated in both human HCC cell lines and normal hepatocytes. Further anti-HCC activity was assessed in nude mice xenografted human HepG2, HUH7, or histidine triad nucleotide-binding protein 1 (HINT1) knockdown HUH7 cells orthotopically or subcutaneously. Mechanistic studies involving HINT1-silenced cells and co-administration with HINT1 upregulation by taraxasterol were conducted to validate the mode of action. Compound DL-2 effectively inhibited HCC cell growth but exhibited minimal cytotoxicity toward normal hepatocyte cell lines. DL-2 exhibited anticancer activity through bioactivation into FdUMP by hepatic HINT1. Comparatively, DL-2 weakly inhibited the orthotopic xenograft derived from HINT1-silenced human HUH7 cells. Systemic use of DL-2 did not produce significant toxicity in mice. In conclusion, we discovered an orally active and liver-targeted dual prodrug of FdUMP for the treatment of HCC. DL-2 is a promising drug used as a substitute for hepatic arterial infusion chemotherapy regimen.