Trifluridine is a thymidylate synthase inhibitor with antiviral and anticancer activities. Trifluridine is phosphorylated intracellularly and competitively inhibits DNA polymerase, and Trifluridine incorporates into viral DNA. Trifluridine improves bioavailability by inhibiting thymidine phosphorylase (TP) and incorporates into tumor DNA. Trifluridine can be used in studies on herpes simplex virus keratoconjunctivitis, acyclovir-resistant HSV infection, and metastatic colorectal cancer and other gastrointestinal tumors[1-4].
In vitro, HT-29, HCT-15 and HCT116 cells were pretreated with 4μM Trifluridine for 24h and then exposed to 8Gy ionizing radiation for 10-12 days. Trifluridine increased radiation dose modification factor, increased intracellular DNA double-strand break levels, elevated RAD51 protein expression, induced apoptotic proteins including cleaved PARP and cleaved caspase-3[5]. HCT116-GFP cells and PBMCs stimulated with anti-CD3 and IL-2 were treated with 3-10μM Trifluridine for 72h. Trifluridine decreased tumor cell viability and increased apoptosis, dose-dependently elevated extracellular ATP and HMGB1, increased IL-2, GM-CSF, IFN-γ and TNF-α secretion. HCT116 cells and PBMCs were treated with 3μM Trifluridine for 12 or 72h. Trifluridine downregulated CCNB1, CDK1 and TOP2A, upregulated TP53I3, CDKN1A and BBC3 in HCT116 cells[6]. Human colorectal cancer cells (HCT116, RKO, HT-29 cells, etc.) were treated with 10nM-1mM Trifluridine for 3 days. Trifluridine decreased cell viability[7].
In vivo, female BALB/C mice received 4T1 cells implanted into the mammary fat pad and were given 75-150mg/kg Trifluridine by gavage daily for 10 days. Trifluridine inhibited implanted triple-negative breast cancer tumor growth, reduced tumor size and weight, and decreased tumor Ki67 and PCNA protein expression[8]. BALB/c nu/nu nude mice bearing intraperitoneal HT-29, HCT116 or MKN45 cells were orally administered 136.7mg/kg/day Trifluridine and 63.9mg/kg/day tipiracil twice daily for 5 days on and 2 days off per week for 6 weeks. Trifluridine prolonged median survival time of tumor-bearing mice. Trifluridine inhibited peritoneal dissemination progression[9]. BALB/c nu/nu nude mice subcutaneously inoculated with DLD-1 or DLD-1/5-FU cells were orally administered 102.1mg/kg/day Trifluridine and 47.9mg/kg/day tipiracil twice daily for 14 days. Trifluridine inhibited tumor growth of DLD-1 and DLD-1/5-FU[10].
References:[1] Okayama T, Yoshisue K, Kuwata K, et al. Involvement of concentrative nucleoside transporter 1 in intestinal absorption of trifluorothymidine, a novel antitumor nucleoside, in rats. J Pharmacol Exp Ther. 2012 Feb;340(2):457-62.
[2] Jia HJ, Zhou M, Vashisth MK, et al. Trifluridine induces HUVECs senescence by inhibiting mTOR-dependent autophagy. Biochem Biophys Res Commun. 2022 Jun 25;610:119-126.
[3] Suzuki N, Nakagawa F, Takechi T. Trifluridine/tipiracil increases survival rates in peritoneal dissemination mouse models of human colorectal and gastric cancer. Oncol Lett. 2017 Jul;14(1):639-646.
[4] Tanaka N, Sakamoto K, Okabe H, et al. Repeated oral dosing of TAS-102 confers high trifluridine incorporation into DNA and sustained antitumor activity in mouse models. Oncol Rep. 2014;32(6):2319-26.
[5] Matsuoka K, Kobunai T, Nukatsuka M, et al. Improved chemoradiation treatment using trifluridine in human colorectal cancer cells in vitro. Biochem Biophys Res Commun. 2017 Dec 2;494(1):249-55.
[6] Selvin T, Fasterius E, Jarvius M, et al. Single-cell transcriptional pharmacodynamics of trifluridine in a tumor-immune model. Sci Rep. 2022 Jul 13;12:11960.
[7] Kataoka Y, Iimori M, Niimi S, et al. Cytotoxicity of trifluridine correlates with the thymidine kinase 1 expression level. Sci Rep. 2019 May 28;9:7964.
[8] Li J, Liu J, Wang R, et al. Trifluridine selectively inhibits cell growth and induces cell apoptosis of triple-negative breast cancer. Am J Cancer Res. 2020 Feb 1;10(2):507-522.
[9] Suzuki N, Nakagawa F, Takechi T. Trifluridine/tipiracil increases survival rates in peritoneal dissemination mouse models of human colorectal and gastric cancer. Oncol Lett. 2017;14(1):639-46.
[10] Suzuki N, Nakagawa F, Matsuoka K, et al. Effect of a novel oral chemotherapeutic agent containing a combination of trifluridine, tipiracil and the novel triple angiokinase inhibitor nintedanib, on human colorectal cancer xenografts. Oncol Rep. 2016;36(6):3123-30.