CA-074 methyl ester (Cathepsin B Inhibitor IV) is a specific inhibitor of Cathepsin B with neuroprotective, anti-cancer, and anti-inflammatory effects.

CA-074Me能够在活体HL-60细胞和血液形态的Trypanosoma brucei brucei中抑制cathepsin L，但在没有硫醇的情况下不抑制cathepsin L。CA-074Me在细胞内酯酶的作用下转化为CA-074，因此能在GSH耗尽的HL-60细胞中抑制cathepsin B。建议在活细胞中选择性地抑制cathepsin B时使用CA-074而不是CA-074Me[1]。在CA074Me处理的成肌细胞中，肌管大小和数量以及诱导的融合相关肌酸磷酸激酶活性和肌球蛋白重链蛋白水平减少了30至50%。这些减少也与剂量相关。CA074Me的微摩尔浓度能够抑制分化成肌细胞中的catB活性[2]。

将CA074Me给药于伦敦APP小鼠，可显著改善记忆缺失，降低大脑中的淀粉样斑块负荷，减少大脑中Aβ40和Aβ42的水平，并且与未经治疗的对照动物相比，减少由β-分泌酶从APP裂解产生的C末端β-分泌酶片段(CTFβ)。在表达有Swe突变的β-分泌酶位点的APP的小鼠（瑞典/伦敦APP小鼠）中，它对这些参数没有影响。在体内通过脑室内给药CA074Me给正常的豚鼠，可以大幅降低大脑中的Aβ水平，并抑制β-分泌酶活性[3]。

After seven days of cell culture and osteoclast generation, the media is removed and washed three times with PBS. BMMs are fixed with a fixing solution supplied by the manufacturer. The cells are incubated at 37°C with a solution containing deionized water, Fast Garnet GBC, Napthol phosphate, Acetate, and Tartrate for 1 h. The staining solution is removed, washed with PBS (3×), and air-dried. TRAP positive cells with three or more nuclei across whole culture area are counted as multinucleated osteoclasts using light microscopy.

HL-60 cells are pre-treated for 24 h with 200 μM BSO followed by 60 min with 1 mM DEM. Thereafter, the cells(1×106/ml) are incubated with 100 μM CA-074 or CA-074Me, in the presence of 1% DMSO, 200 μM BSO and 1 mM DEM at 37°C. Control cultures are treated with 1% DMSO alone or with 100 μM Z-FA-DMK in the presence of 200 μM BSO and 1 mM DEM. Untreated HL-60 cells are incubated with 100 μM CA-074 or CA-074Me, in the presence of 1% DMSO at 37°C. Untreated control cultures are incubated with 1% DMSO alone or with 100 μM Z-FA-DMK. After 2 h incubation, cells are washed three times with PBS/1% glucose and lysed in 100 mM citrate, pH 5.0, 2% Chaps (106 cells/100 μl). Subsequently, the lysate is centrifuged and the clarified supernatant used to assay for proteolytic activity.(Only for Reference)