KGP94 is a selective inhibitor of cathepsin L with an IC50 of 189 nM[1]. KGP94 inhibits migration and invasion of metastatic carcinoma and shows low cytotoxicity (GI50=26.9 µM) against various human cell lines[2].

KGP94 (10 or 20 μM, 24 h) reduces expression of M2 (macrophage) markers (Arginase-1 and CD206) and cells invasion of primary bone marrow-derived macrophages or Raw264.7[3].
KGP94 (25 μM, 24 h) impairs the incasive capacities of both prostate and breat cancer cells by 53% and 88%, respectively[4].KGP94 (25 μM, 24 h) suppresses secreted CTSL activity by 94% and 92% in PC-3ML and MDA-MB-231, repsectively[4].

KGP94 (i.p.; 20 mg/kg; once daily for 3 days) exhibits anti-metastatic and anti-bone resorptive efficacy in a prostate cancer bone metastasis model[5].

[1]. Parker EN, et al. Synthesis and biological evaluation of a water-soluble phosphate prodrug salt and structural analogues of KGP94, a lead inhibitor of cathepsin L. Bioorg Med Chem Lett. 2017 Mar 1. 27(5):1304-1310.
[2]. Munikishore R, et al. An efficient and concise synthesis of a selective small molecule non-peptide inhibitor of cathepsin L: KGP94. Bioorg Chem. 2021 Nov. 116:105317.
[3]. Dykes SS, et al. Cathepsin L secretion by host and neoplastic cells potentiates invasion. Oncotarget. 2019 Sep 17. 10(53):5560-5568.
[4]. Sudhan DR, et al. Cathepsin L inhibition by the small molecule KGP94 suppresses tumor microenvironment enhanced metastasis associated cell functions of prostate and breast cancer cells. Clin Exp Metastasis. 2013 Oct. 30(7):891-902.
[5]. Sudhan DR, et al. Cathepsin L inactivation leads to multimodal inhibition of prostate cancer cell dissemination in a preclinical bone metastasis model. Int J Cancer. 2016 Jun 1;138(11):2665-77.