CA 074

CA 074 is a selective inhibitor of cathepsin B with a K_i value of 2-5 nM. CA 074 is 10000-30000 times more potent against purified rat cathepsin B than against cathepsin H and L^[1]. CA 074 is a synthetic analog of E-64, a natural peptidyl epoxide that irreversibly inhibits most lysosomal cysteine​proteases^[2]. CA 074 cannot cross cell membranes, but its methyl ester form, CA-074 Me (GC15917), can cross cell membranes^[3].

In vitro, CA 074 (10 μM) treatment of HT29, DLD1, and SW480 cells for 2-3 weeks significantly inhibited cell invasion through Matrigel by approximately 45-60% ^[4].

In vivo, CA 074 (10 mg/kg) treated intravenously in mice inoculated with human melanoma cells significantly inhibited tumor growth and the number of lung metastases ^[5]. CA 074 (50 mg/kg) was injected intraperitoneally into 4T1.2 tumor-bearing mice, which significantly inhibited tumor growth, reduced tumor cathepsin B activity, and inhibited lung and bone metastasis^[6]. CA 074 (4 mg/kg) was injected intravenously into rats with focal cerebral ischemia, which significantly reduced the levels of cathepsin B and L and increased the number of eosinophilic (necrotic) and apoptotic neurons in brain tissue^[7].

References:
[1] Towatari T, Nikawa T, Murata M, et al. Novel epoxysuccinyl peptides A selective inhibitor of cathepsin B, in vivo[J]. FEBS letters, 1991, 280(2): 311-315.
[2] Matsumoto K, Mizoue K, Kitamura K, et al. Structural basis of inhibition of cysteine proteases by E‐64 and its derivatives[J]. Peptide Science, 1999, 51(1): 99-107.
[3] Patel N, Nizami S, Song L, et al. CA‐074Me compound inhibits osteoclastogenesis via suppression of the NFATc1 and c‐FOS signaling pathways[J]. Journal of Orthopaedic Research, 2015, 33(10): 1474-1486.
[4] Bian B, Mongrain S, Cagnol S, et al. Cathepsin B promotes colorectal tumorigenesis, cell invasion, and metastasis[J]. Molecular carcinogenesis, 2016, 55(5): 671-687.
[5] Matarrese P, Ascione B, Ciarlo L, et al. Cathepsin B inhibition interferes with metastatic potential of human melanoma: an in vitro and in vivo study[J]. Molecular cancer, 2010, 9: 1-14.
[6] Withana N P, Blum G, Sameni M, et al. Cathepsin B inhibition limits bone metastasis in breast cancer[J]. Cancer research, 2012, 72(5): 1199-1209.
[7] Özkara E, Durmaz R, Özbek Z, et al. The Effect of Ca-074 (Cathepsın B Inhibitor) on Necrotic and Apoptotic Neuronal Cell Death in Model of Cerebral Ischemia[J]. Osmangazi Tıp Dergisi, 2023, 45(5): 781-790.