3'-C-ethynylcytidine

**Semantic type:** Nucleic Acid, Nucleoside, or Nucleotide|Pharmacologic Substance

**Definition:** A synthetic cytidine nucleoside containing a covalently bound ethynyl group with potential antineoplastic and radiosensitizing activities. 3'-C-ethynylcytidine is metabolized in tumor cells to ethynylcytidine triphosphate (ECTP), which inhibits RNA synthesis by competitive inhibition of RNA polymerases I, II and III; subsequently, RNase L is activated, resulting in apoptosis. RNase L is a potent antiviral and antiproliferative endoribonuclease that cleaves singled stranded RNA, causes 28s rRNA fragmentation, and activates Janus Kinase (JAK), a mitochondrial-dependent apoptosis signaling molecule.

**Synonyms:** - 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine - 3'-C-Ethynylcytidine - ECdy - ECyd - TAS-106 - TAS-106