K777 

K777 is a potent, orally active and irreversible cysteine protease inhibitor. K777 is also a potent CYP3A4 inhibitor with an IC₅₀ of 60 nM and a selective CCR4 antagonist featuring the potent chemotaxis inhibition. K777 irreversibly inhibits Cruzain, the major cysteine protease of Trypansoma cruzi, and cathepsins B and L. K777 is a broad-spectrum antiviral by targeting cathepsin-mediated cell entry. K777 inhibits SARS-CoV and EBOV pseudovirus entry with IC₅₀ values of 0.68 nM and 0.87 nM, respectively^[1][2][3].

K777 (K11777) can inhibit entry driven by other viral envelope proteins, including HIV-based pseudotypes bearing spikes from coronaviruses (SARS-CoV, HCoV-229E, NL63, MERS-CoV) or glycoproteins from filoviruses (EBOV, SUDV, TAFV, RESTV, BEBOV and MARV).
K777 inhibits SARS-CoV, HCoV-229E, NL63, MERS-CoV, EBOV, SUDV, TAFV, RESTV, BEBOV, MARV and Nipah pseudovirus entry with IC₅₀ values of 0.68 nM, 1.48 nM, 6.78 nM, 46.12 nM, 0.87 nM, 1.14 nM, 2.26 nM, 3.37 nM, 5.91 nM, 1.9 nM and 0.42 nM, respectively.
In contrast, 100 nM K777 does not inhibit infection mediated by envelope glycoproteins from an alphavirus (CHIKV), a rhabdovirus (VSV), a flavivirus (HCV), the retroviruses MLV-A and XMRV or two arenaviruses, Lassa and Junin virus^[1].
K777 alone demonstrates up to ~ 70% inhibition of 229E-S-mediated transduction. Simultaneous treatment with Camostat and K777 increases inhibition to ~ 90%. Similar inhibition patterns are obtained using the human intestinal epithelial cell line Caco-2, which express endogenous TMPRSS2 and cathepsins^[1].
K777 inhibits both CCL17 binding and CCL17-induced chemotaxis in Hut78 cells (IC₅₀ of 57 and 8.9 nM, respectively). The K777-mediated inhibition of chemotaxis is potent even in the presence of a 10-fold higher concentration of CCL17.
K777 induces CCR4 internalization, with a ～50% reduction of cell surface CCR4. K777 does not inhibit CXCR4-induced chemotaxis or internalization and did not bring about Ca²⁺ mobilization by itself^[3].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

K777 (K11777; 35-105 mg/kg; oral administration; twice a day; for 10 days; C57BL/6 IFN-γR-KO mice) treatment rescues mice from otherwise lethal infections^[4] .

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

574.73

C₃₂H₃₈N₄O₄S

233277-99-1

Solid

White to off-white

O=C(N1CCN(C)CC1)N[C@@H](CC2=CC=CC=C2)C(N[C@@H](CCC3=CC=CC=C3)/C=C/S(=O)(C4=CC=CC=C4)=O)=O

Room temperature in continental US; may vary elsewhere.

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month. When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Zhou Y, et al. Protease inhibitors targeting coronavirus and filovirus entry. Antiviral Res. 2015 Apr;116:76-84.  [Content Brief]

  [2]. Jacobsen W, et al. In vitro evaluation of the disposition of A novel cysteine protease inhibitor. Drug Metab Dispos. 2000 Nov;28(11):1343-51.  [Content Brief]

  [3]. Sato T, et al. Internalization of CCR4 and inhibition of chemotaxis by K777, a potent and selective CCR4 antagonist. Pharmacology. 2013;91(5-6):305-13.  [Content Brief]

  [4]. Ndao M, et al. A cysteine protease inhibitor rescues mice from a lethal Cryptosporidium parvum infection. Antimicrob Agents Chemother. 2013 Dec;57(12):6063-73.  [Content Brief]