The novel anti-cancer fluoropyrimidine NUC-3373 is a potent inhibitor of thymidylate synthase and an effective DNA-damaging agent

Abstract

Introduction Fluoropyrimidines, principally 5-fluorouracil (5-FU), remain a key component of chemotherapy regimens for multiple cancer types, in particular colorectal and other gastrointestinal malignancies. To overcome key limitations and pharmacologic challenges that hinder the clinical utility of 5-FU, NUC-3373, a phosphoramidate transformation of 5-fluorodeoxyuridine, was designed to improve the efficacy and safety profile as well as the administration challenges associated with 5-FU. Methods Human colorectal cancer cell lines HCT116 and SW480 were treated with sub-IC50 doses of NUC-3373 or 5-FU. Intracellular activation was measured by LC–MS. Western blot was performed to determine binding of the active anti-cancer metabolite FdUMP to thymidylate synthase (TS) and DNA damage. Results We demonstrated that NUC-3373 generates more FdUMP than 5-FU, resulting in a more potent inhibition of TS, DNA misincorporation and subsequent cell cycle arrest and DNA damage in vitro. Unlike 5-FU, the thymineless death induced by NUC-3373 was rescued by the concurrent addition of exogenous thymidine. 5-FU cytotoxicity, however, was only reversed by supplementation with uridine, a treatment used to reduce 5-FU-induced toxicities in the clinic. This is in line with our findings that 5-FU generates FUTP which is incorporated into RNA, a mechanism known to underlie the myelosuppression and gastrointestinal inflammation associated with 5-FU. Conclusion Taken together, these results highlight key differences between NUC-3373 and 5-FU that are driven by the anti-cancer metabolites generated. NUC-3373 is a potent inhibitor of TS that also causes DNA-directed damage. These data support the preliminary clinical evidence that suggest NUC-3373 has a favorable safety profile in patients.

Secondary metabolite profiling using HR-LCMS, antioxidant and anticancer activity of Bacillus cereus PSMS6 methanolic extract: In silico and in vitro study

“…In this regard, the therapeutic index is an important parameter as it includes anticancer activity and eventual toxicity to normal cells. This value is the ratio of the concentration of the extract at which 50 % of cytotoxicity occurred in a normal cell line to that of the test solution at which 50 % of cancer cell death occurred in cancer cell lines [ [52] , [53] ]. According to the American National Cancer Institute (NCI) recommendations, the limit of activity for crude extracts is 50 % inhibition (IC50) of proliferation was less than 30 g/ml following a 24-hour exposure duration [ 54 ].…”

Advances and key focus areas in gastric cancer immunotherapy: A comprehensive scientometric and clinical trial review (1999-2023)

“…Over the past decades, 5-fluorouracil has remained a mainstay in the realm of chemotherapy. Recently, researchers have introduced NUC-3373, which has demonstrated a more favorable safety profile in patients[ 108 ]. A phase I/II clinical trial is currently centered on the use of NUC-3373 in conjunction with other agents in patients with advanced solid tumors, including GC (NCT05714553).…”

Review of Prodrug and Nanodelivery Strategies to Improve the Treatment of Colorectal Cancer with Fluoropyrimidine Drugs

“…NUC-3373 is a phosphoramidite prodrug of FdUMP that enters cells independent of nucleoside transporters and then undergoes metabolism to release FdUMP, bypassing a requirement for enzymatic phosphorylation by thymidine kinase. Strong TS inhibition is detected in cancer cells treated with NUC-3373 and the compound is in phase 1 clinical trials [ 46 ]. NUC-3373 is one example of a “ProTide” strategy in which biologically active nucleosides are delivered with the hydroxyl of the 5′-monophosphate blocked by an aromatic group or an amino acid ester [ 47 ].…”